Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. CT Head Although a head CT is acceptable as a means to document brain metastases (FIGO), the formalized consensus of the EOTTD favors MRI over CT in the detection of brain metastases [6]. Because GTN metastases are typically vascular, IV contrast enhancement is necessary to improve lesion detection.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. CT Abdomen and Pelvis CT abdomen and pelvis is useful to exclude disseminated disease in patients with high-risk or recurrent GTN who are being considered for salvage hysterectomy [16] or to evaluate for recurrence of tumors after surgical resection. In the specific context of oligometastatic disease to lung with potential for pulmonary wedge resection, CT abdomen and pelvis has particular utility for exclusion of additional disease sites [16,18]. Because GTN metastases are typically vascular, IV contrast enhancement is necessary to improve lesion detection.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. FDG-PET/CT Skull Base to Mid-Thigh The role of FDG-PET/CT in the evaluation of patients with refractory or recurrent GTN is incompletely defined and evolving, given the uncommon nature of the disease. FDG-PET/CT may help to identify the site of active or occult disease and facilitate planning for surgical resection and potential cure [10,66,67,69,72]. However, the evidence basis is small and retrospective.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Variant 4: Assessment of complications: GTD and GTN. Patients with GTD can present with complications related to invasive mole or metastatic lesions, in large part because of the highly vascular nature of this disease process. Some of these complications can be severe and life- threatening. Hemorrhage is the most common complication and can result from tumor invading the uterus or from other sites of metastatic tumor involvement, including lungs, brain, vagina, and liver [2,16,50,73]. Selective angiographic localization and embolization can be used to identify and treat lesions with active hemorrhage as well as post-treatment sequelae, such as arteriovenous malformation [18]. Hysterectomy may be indicated for severe uterine hemorrhage or rupture [2,18]. Although rare in the United States, patients with invasive mole may present with hemoperitoneum that is due to molar tissue penetrating the full thickness of the myometrium [20]. Finally, adnexal torsion or rupture may occasionally complicate theca lutein cysts, necessitating surgical removal [16]. Imaging evaluation in the setting of suspected GTN complications should be guided by location of clinical signs and symptoms.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. US Pelvis Transabdominal Transvaginal US has improved sensitivity and specificity in the diagnosis of uterine masses and abnormalities when compared to transabdominal US, although given the rarity of this disorder, series comparing both modalities in patients with GTD are lacking [32]. At some institutions, patients with GTN are not evaluated with transvaginal US due to the risk of major bleeding as a consequence of a nondetected vaginal metastasis [37].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. US Duplex Doppler Pelvis GTN can be complicated by uterine vascular malformations such as arteriovenous shunts and pseudoaneurysms, described in up to 15% of cases following complete response to chemotherapy, and best delineated with Doppler US [44]. Although these findings are insignificant if asymptomatic and associated with a normal hCG, such malformations occasionally result in life-threatening vaginal or intraperitoneal hemorrhage [44].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Gestational Trophoblastic Disease Radiography Chest We are unaware of any recent formal assessment regarding the use of chest radiography to assess pulmonary complications in GTN. Lung infarct and secondary pulmonary arterial hypertension associated with trophoblastic tumor thrombus may be appreciated on chest radiography. Likewise, sequelae of endobronchial metastasis such as volume loss or airspace disease and pleural effusions that follow hemorrhage into parenchymal and intravascular metastases could potentially be visible [44,45].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. CT Chest A variety of pulmonary complications may be evaluated using chest CT [44,45], including trophoblastic tumor thrombus, associated lung infarct, and secondary pulmonary arterial hypertension. Unusual manifestations of lung metastases may be perceptible such as an endobronchial lesion with secondary obstruction and volume loss. Airspace disease and pleural effusion may follow hemorrhage into parenchymal and intravascular metastases [44,45]. Because detection of these complications may require opacification of the vessels, IV contrast enhancement is necessary to improve lesion conspicuity, although hemorrhagic complications would be visible on an unenhanced study.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. CT Head Craniotomy with surgical decompression is generally indicated for acute symptomatic treatment of patients with intracranial hemorrhage [16]. CT can be used to identify and localize lesions or to detect signs of increased intracranial pressure and mass effect in patients with acute neurologic symptoms and signs of deterioration. Hemorrhagic complications and structural changes related to mass effect would be visible without IV contrast, although lesion detection would be improved with IV contrast.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. CT Abdomen and Pelvis CT is indicated to detect metastatic disease in the staging of patients with GTN, but can also be used to identify sites of active hemorrhage or other tumor-related complications [74]. Liver metastases can be associated with catastrophic intraperitoneal hemorrhage and may require selective angiographic embolization techniques [16]. Use of CT abdomen and pelvis should be prompted by abdominopelvic location of patient symptoms in context of known GTN. Hemorrhagic complications would be evident without the use of IV contrast. IV contrast may be required to detect individual nonhemorrhagic lesions.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. MRI Head Craniotomy with surgical decompression is generally indicated for acute symptomatic treatment of patients with intracranial hemorrhage [16]. MRI can be used to identify and localize lesions or to detect signs of increased intracranial pressure and mass effect in patients with acute neurologic symptoms and signs of deterioration. Structural changes related to mass effect or signal characteristics associated with hemorrhage would be visible without IV contrast. Detection of individual lesions would be improved with IV contrast.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. MRI Pelvis Although pelvic MRI is considered a problem-solving tool in patients with vaginal bleeding [75], no studies specifically evaluate the use of MRI for GTD-related complications. Tortuous coiled flow voids corresponding to vessels located within the myometrium generally reflect a post-treatment vascular malformation. Complications related to hemorrhage or vascular malformations would be visible without IV contrast, although the detection of individual lesions and structural changes related to complications may be improved with IV contrast.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. FDG-PET/CT Skull Base to Mid-Thigh We are unaware of any evidence that evaluates or supports the role of FDG-PET/CT in assessing complications in patients with GTN.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Gestational Trophoblastic Disease


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch.acr.org/list. The appendix includes the strength of evidence assessment and the final rating round tabulations for each recommendation.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease


Staging and Surveillance of Testicular Cancer. Malignant testicular germ-cell tumors metastasize by either the hematogenous or lymphatic route. Nodal metastases typically follow the testicular lymphatic drainage pathway alongside the testicular veins to regional lymph node groups. Tumors from the left testis will metastasize to the left para-aortic nodal group just below the left renal vein and interaortocaval group, whereas right testicular tumors will metastasize to the paracaval, precaval, and interaortocaval groups. Crossover of lymphatic involvement may occur in either right-sided or left-sided tumors; however, it is unusual to have contralateral metastasis without involvement of the ipsilateral nodes [4]. Further spread to nonregional lymph node groups, including common iliac, internal iliac, and external iliac nodes, or via the thoracic duct to the left supraclavicular nodes and subsequently to the lungs, constitutes distant metastasis [5]. Prior scrotal or inguinal surgery can alter the lymphatic drainage; therefore, external iliac and inguinal lymph nodes are considered regional in that context [6].


Staging and Surveillance of Testicular Cancer. Staging of testicular cancer is based upon determination of extent of disease and follows the tumor, nodes, and metastases (TNM) staging system used by the American Joint Committee on Cancer [5]. TNM staging of testicular cancer is a major factor that determines treatment and prognosis in men with testicular cancer. Imaging is used to assess for expected locations of lymph node involvement and metastatic disease. Most patients with stage IA and IB pure seminoma testicular cancers are cured by orchiectomy [7]. Surveillance is strongly preferred in this group of patients; however, because 15% to 20% of men experience relapse, adjuvant therapy with one or two cycles of single-agent carboplatin or radiotherapy to decrease risk of relapse can be considered in certain high-risk patients [8-11]. Irrespective of management strategy, disease-specific survival approaches 100% [8-11]. In men who relapse while on surveillance in stage I pure seminoma testicular cancer, most relapses occur in the abdominal and pelvic lymph nodes [8-11]. The 2021 National Comprehensive Cancer Network (NCCN) guidelines recommend, apart from physical examination and serum tumor markers, imaging surveillance to detect relapse for 5 years after orchiectomy [8]. In this document, clinical suspicion of tumor relapse indicates abnormal physical examination or serum markers and no clinical suspicion of tumor relapse indicates a normal physical examination and tumor markers. The management strategies and prognosis of men with stage II and higher pure seminoma testicular cancer and nonseminoma testicular cancer, as well as restaging and follow-up approaches, are beyond the scope of this document but have been described in detail by the 2021 NCCN guidelines [8].


Staging and Surveillance of Testicular Cancer. aOttawa Hospital Research Institute and the Department of Radiology, The University of Ottawa, Ottawa, Ontario, Canada. bPanel Chair, University of Chicago, Chicago, Illinois. cPanel Vice-Chair, Duke University Medical Center, Durham, North Carolina. dMemorial Sloan Kettering Cancer Center, New York, New York. eUniversity of Minnesota, Minneapolis, Minnesota. fUrology Clinics of North Texas, Dallas, Texas; American Urological Association. gUniversity of Wisconsin, Madison, Wisconsin. hUPMC, Pittsburgh, Pennsylvania; American Urological Association. iStanford University Medical Center, Stanford, California. jEmory University Hospital, Atlanta, Georgia. kThe Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada, Primary care physician. lNational Institutes of Health, Bethesda, Maryland. mSpecialty Chair, University of Alabama at Birmingham, Birmingham, Alabama.


Staging and Surveillance of Testicular Cancer. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization.


Staging and Surveillance of Testicular Cancer. Reprint requests to: publications@acr.org


Staging and Surveillance of Testicular Cancer. Staging and Surveillance of Testicular Cancer Discussion of Procedures by Variant Variant 1: Initial staging of pure seminoma testicular cancer. Diagnosed by orchiectomy. Bone Scan Whole Body Bone metastases from testicular cancer are uncommon. In one study, bone scan was able to detect metastases to the iliac bones ipsilateral to the testicular tumor before they were detectable by CT [12].


Staging and Surveillance of Testicular Cancer. CT Abdomen and Pelvis CT is the reference standard imaging test used for assessing the retroperitoneum for the presence of metastatic lymphadenopathy. CT is rapid, reproducible, and provides excellent imaging assessment of the para-aortic and paracaval regions [13-15]. Challenges related to CT are that many young men have little retroperitoneal fat, which may be an impediment for readers interpreting the study, and that CT cannot detect metastatic disease in lymph nodes of normal size. Additionally, inflammatory lymph nodes cannot be differentiated from those that are enlarged from metastases [16].


Staging and Surveillance of Testicular Cancer. Lymph nodes >1 cm in short axis are highly suspicious for metastatic disease, particularly if they are located in the hilar regions of the kidney or in the para-aortic or caval areas (eg, testicular cancer landing zones). Various studies have established the accuracy of CT in detecting metastatic retroperitoneal lymph nodes from testicular cancer, which ranges from 73% to 97%, sensitivity ranges from 65% to 96%, and specificity from 81% to 100% [7,17-22]. Data also indicate that the accuracy of CT declines in patients with limited disease (eg, stage N1 and stage N2) and also if the upper limit of normal lymph node size is lowered [15,17,21]. Of note, most of these studies are relatively old and were performed using single-slice CT; however, limited newer data suggest similar accuracy using multi- slice CT compared with single-slice CT [23].


Staging and Surveillance of Testicular Cancer. It is important to recognize that a significant percentage of metastatic lymph nodes will be <1 cm, up to 60% in one series [24]. For this reason, some authors suggest using a cut-off value of 0.7 cm to 0.8 cm in testicular cancer at the expense of reduced specificity [24,25]. These cut-off values are for the short-axis measurement when assessing the likelihood of nodal disease (N0 versus N1 disease); however, when assessing the nodal burden, the lymph nodes should be measured in long axis (eg, N1 versus N2 and N3 disease) [6,25]. Two studies have also evaluated the value of nodal craniocaudal length or volume as risk factors for recurrence in testicular cancer [26,27]. Another study comparing lymph node measurements performed by expert radiologists, other observers, and a semiautomated process showed excellent correlation between measurements, indicating that the task of actually measuring lymph nodes, which can be time consuming and tedious, could potentially be delegated or automated in the future [28].


Staging and Surveillance of Testicular Cancer. The use of iodinated intravenous (IV) contrast media, as well as oral contrast media, may aid in detection of retroperitoneal lymph nodes, clarifying the adjacent normal anatomic structures including blood vessels and the duodenum [29].


Staging and Surveillance of Testicular Cancer. CT Chest Although CT is more sensitive than radiography for detecting recurrent disease in the chest [30,31], this added sensitivity is offset by lower specificity and a higher false positive detection rate for abnormalities that are not related to testicular cancer metastases [32]. Chest CT is recommended during initial staging if chest radiograph is abnormal or when abdominal CT is abnormal [8]. Detection of mediastinal and hilar lymph nodes may be aided by the use of iodinated IV contrast media [33].


Staging and Surveillance of Testicular Cancer. FDG-PET/CT Whole Body Fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET has been used for staging and restaging patients with testicular cancer, but its incremental value in staging patients compared with CT or MRI has yet to be defined. For initial staging, PET may be slightly more sensitive than CT [34-39], but it is not recommended by the NCCN [40].


Staging and Surveillance of Testicular Cancer. MRI Abdomen and Pelvis MRI has also been studied for staging and surveillance of testicular cancer, to identify metastatic retroperitoneal lymphadenopathy [41-46]. Limited evidence from single-institution studies indicates comparable efficacy to CT for detection of retroperitoneal lymphadenopathy, notably without the need for gadolinium-based contrast agents (GBCAs) [41,43].


Staging and Surveillance of Testicular Cancer. A limitation of the literature regarding MRI for detection of metastatic retroperitoneal lymphadenopathy is that the studies are older and do not incorporate diffusion-weighted imaging (DWI). DWI can substantially improve identification of lymph nodes; however, it is still limited by significant overlap between benign and malignant


Staging and Surveillance of Testicular Cancer. Staging and Surveillance of Testicular Cancer lymph nodes [6]. A study published in 2020 showed comparable accuracy between MRI, which included DWI and omitted GBCAs, and CT for detection of metastatic retroperitoneal lymph nodes in testicular germ-cell tumors [47].


Staging and Surveillance of Testicular Cancer. MRI Head MRI of the head, without and with GBCAs, is recommended during the initial staging of testicular cancer if the patient is symptomatic or has high-risk features (eg, human chorionic gonadotropin [hCG] >5000 IU/L or extensive lung metastases) [8-11].


Staging and Surveillance of Testicular Cancer. Radiography Chest Studies have shown that chest radiography is beneficial in pure seminoma testicular cancer during the initial staging of testicular cancer to assess for the presence of pulmonary metastases [48,49]. Chest CT is recommended during initial staging if chest radiograph or abdominal CT is abnormal [8].


Staging and Surveillance of Testicular Cancer. US Abdomen and Retroperitoneum Ultrasound (US) of the abdomen and retroperitoneum to detect retroperitoneal lymph node metastases is less accurate and reproducible than CT, MRI, or PET/CT [50].


Staging and Surveillance of Testicular Cancer. US Scrotum Scrotal US is frequently used and should always be the initial imaging modality in assessing patients with scrotal masses. Scrotal US should always be performed during the initial workup of a scrotal mass before orchiectomy to localize the tumor, plan surgery, and clear the contralateral testicle of disease [40]. After initial triage and orchiectomy, scrotal US does not have a role in the initial staging or restaging of men with testicular cancer diagnosis established by orchiectomy unless there is concern for contralateral tumor or equivocal clinical examination [8].


Staging and Surveillance of Testicular Cancer. Variant 2: Initial staging of nonseminoma testicular cancer. Diagnosed by orchiectomy. Bone Scan Whole Body Bone metastases from testicular cancer are uncommon. In one study, bone scan was able to detect metastases to the iliac bones ipsilateral to the testicular tumor before they were detectable by CT [12].


Staging and Surveillance of Testicular Cancer. The use of iodinated IV contrast media, as well as oral contrast media, may aid in detection of retroperitoneal lymph nodes, clarifying the adjacent normal anatomic structures including blood vessels and the duodenum [29].


Staging and Surveillance of Testicular Cancer. Staging and Surveillance of Testicular Cancer CT Chest Although CT is more sensitive than radiography for detecting recurrent disease in the chest [30,31], this added sensitivity is offset by lower specificity and a higher false positive detection rate for abnormalities that are not metastatic [32].


Staging and Surveillance of Testicular Cancer. For nonseminoma testicular cancer, a slight advantage for chest CT has been noted compared with chest radiography [48,51], and chest CT is recommended during the initial staging of nonseminoma testicular cancer by the NCCN and European Association of Urology guidelines [8,9]. Detection of mediastinal and hilar lymph nodes may be aided by the use of iodinated IV contrast media [33].


Staging and Surveillance of Testicular Cancer. FDG-PET/CT Whole Body FDG-PET has been used for staging and restaging patients with testicular cancer, but its incremental value in staging patients compared with CT or MRI has yet to be defined. For initial staging, PET may be slightly more sensitive than CT [34-39], but it is not recommended by the NCCN [40].


Staging and Surveillance of Testicular Cancer. MRI Abdomen and Pelvis MRI has also been studied for staging and surveillance of testicular cancer to identify metastatic retroperitoneal lymphadenopathy [41-46]. Limited evidence from single-institution studies indicates comparable efficacy to CT for detection of retroperitoneal lymphadenopathy, notably without the need for GBCAs [41,43].


Staging and Surveillance of Testicular Cancer. A limitation of the literature regarding MRI for detection of metastatic retroperitoneal lymphadenopathy is that the studies are older and do not incorporate DWI. DWI can substantially improve identification of lymph nodes; however, it is still limited by significant overlap between benign and malignant lymph nodes [6]. A study published in 2020 showed comparable accuracy between MRI, which included DWI and omitted GBCAs, and CT for detection of metastatic retroperitoneal lymph nodes in testicular germ-cell tumors [47].


Staging and Surveillance of Testicular Cancer. MRI Head MRI of the head, without and with GBCAs, is recommended during the initial staging of testicular cancer if the patient is symptomatic or has high-risk features (eg, hCG >5000 IU/L, extensive lung metastases, choriocarcinoma, nonpulmonary visceral metastases, or alpha-fetoprotein [AFP] >10,000 ng/mL) [8-11].


Staging and Surveillance of Testicular Cancer. Radiography Chest Studies have shown that chest radiography is beneficial during the initial staging of testicular cancer, assessing for pulmonary metastases [48,49]. For nonseminoma testicular cancer, a slight advantage for chest CT has been noted compared with chest radiography [48,51], and chest CT is useful during the initial staging of nonseminoma testicular cancer by the NCCN and European Association of Urology guidelines [8,9].


Staging and Surveillance of Testicular Cancer. US Abdomen and Retroperitoneum US of the abdomen and retroperitoneum to detect retroperitoneal lymph node metastases is less accurate and reproducible than CT, MRI, or PET/CT [50].


Staging and Surveillance of Testicular Cancer. Variant 3: Surveillance of stage IA and IB pure seminoma testicular cancer. Diagnosed by orchiectomy. No clinical suspicion of recurrence. Bone Scan Whole Body Bone metastases from testicular cancer are uncommon. In one study, bone scan was able to detect metastases to the iliac bones ipsilateral to the testicular tumor before they were detectable by CT [12].


Staging and Surveillance of Testicular Cancer. Staging and Surveillance of Testicular Cancer CT Abdomen and Pelvis CT is the reference standard imaging test used for assessing the retroperitoneum for the presence of metastatic lymphadenopathy. CT is rapid, reproducible, and provides excellent imaging assessment of the para-aortic and paracaval regions [13-15]. Challenges related to CT are that many young men have little retroperitoneal fat, which may be an impediment for readers interpreting the study, and that CT cannot detect metastatic disease in lymph nodes of normal size. Additionally, inflammatory lymph nodes cannot be differentiated from those that are enlarged from metastases [16].


Staging and Surveillance of Testicular Cancer. Lymph nodes >1 cm in short axis are highly suspicious for metastatic disease, particularly if they are located in the hilar regions of the kidney or in the para-aortic or caval areas (eg, testicular cancer landing zones). Various studies have established the accuracy of CT in detecting metastatic retroperitoneal lymph nodes from testicular cancer, which ranges from 73% to 97%, sensitivity ranges from 65% to 96%, and specificity from 81% to 100% [7,17-22]. Data also indicate that the accuracy of CT declines in patients with limited disease (eg, stage N1 and stage N2) and also if the upper limit of normal lymph node size is lowered [15,17,21]. Of note, most of these studies are relatively old and were performed using single-slice CT; however, limited newer data suggest similar accuracy using multi- slice CT compared with single-slice CT [23].


Staging and Surveillance of Testicular Cancer. It is important to recognize that a significant percentage of metastatic lymph nodes will be <1 cm, up to 60% in one series [24]. For this reason, some authors suggest using a cut-off value of 0.7 cm to 0.8 cm in testicular cancer at the expense of reduced specificity [24,25]. These cut-off values are for the short-axis measurement when assessing the likelihood of nodal disease (N0 versus N1 disease); however, when assessing the nodal burden the lymph nodes should be measured in long axis (eg, N1 versus N2 and N3 disease) [6,25]. Two studies have also evaluated the value of nodal craniocaudal length or volume as risk factors for recurrence in testicular cancer [26,27]. Another study comparing lymph node measurements performed by expert radiologists, other observers, and a semiautomated process showed excellent correlation between measurements, indicating that the task of actually measuring lymph nodes, which can be time consuming and tedious, could potentially be delegated or automated in the future [28].


Staging and Surveillance of Testicular Cancer. Surveillance is strongly preferred for patients with stage I pure seminoma testicular cancer [8-11]. Surveillance protocols no longer include chest CT [30] and may eliminate pelvic CT, except in cases in which the pelvis is deemed high risk [53-55]. The number and frequency schedule of follow-up CT examinations of the abdomen and pelvis is variable [56]. Most recently, the 2021 NCCN guidelines recommends different intensity of follow-up for stage I pure seminoma testicular cancer and nonseminoma testicular cancer, which also depends on the presence or absence of risk factors for metastatic disease [8].


Staging and Surveillance of Testicular Cancer. CT Chest Although CT is more sensitive than radiography for detecting recurrent disease in the chest [30,31], this added sensitivity is offset by lower specificity and a higher false positive detection rate for abnormalities that are not metastatic [32]. Detection of mediastinal and hilar lymph nodes may be aided by the use of iodinated IV contrast media [33].


Staging and Surveillance of Testicular Cancer. Several studies indicate that chest radiography is sufficient when compared with CT for follow-up of stage I seminomas [30,32,49,54], and the NCCN advise CT chest only be performed if the patient is symptomatic [40].


Staging and Surveillance of Testicular Cancer. FDG-PET/CT Whole Body FDG-PET has been used for staging and restaging patients with testicular cancer, but its incremental value in staging patients compared with CT or MRI has yet to be defined. For initial staging, PET may be slightly more sensitive than CT [34-39]. The use of PET for surveillance of stage 1A and 1B pure seminoma is not well studied.


Staging and Surveillance of Testicular Cancer. A limitation of the literature regarding MRI for detection of metastatic retroperitoneal lymphadenopathy is that the studies are older and do not incorporate DWI. DWI can substantially improve identification of lymph nodes; however, it is still limited by significant overlap between benign and malignant lymph nodes [6]. A study published


Staging and Surveillance of Testicular Cancer. Staging and Surveillance of Testicular Cancer in 2020 showed comparable accuracy between MRI, which included DWI and omitted GBCAs, and CT for detection of metastatic retroperitoneal lymph nodes in testicular germ-cell tumors [47].


Staging and Surveillance of Testicular Cancer. MRI Head MRI of the head is not recommended during the surveillance of pure seminoma testicular cancer unless the patient is symptomatic.


Staging and Surveillance of Testicular Cancer. Radiography Chest In pure seminoma testicular cancer under surveillance, studies have shown that lung relapses are rarely detected by chest radiography alone, with most relapses detected by abnormal serum markers or abdominal and pelvic CT scan [57-59], calling into question the value of chest radiography in surveillance of stage I pure seminoma testicular cancer. The 2021 NCCN guidelines, however, do provide an option for chest radiography for stage I pure seminoma testicular cancer patients undergoing surveillance if clinically indicated [8].


Staging and Surveillance of Testicular Cancer. US Scrotum Scrotal US does not have a role in the restaging of men with testicular cancer diagnosis established by orchiectomy unless there is concern for contralateral tumor or equivocal clinical examination [8]. Scrotal US should always be performed during the initial workup of a scrotal mass before orchiectomy to localize the tumor, plan surgery, and clear the contralateral testicle of disease [40]. After initial triage and orchiectomy, scrotal US does not have a role in the initial staging or restaging of men with testicular cancer diagnosis established by orchiectomy unless there is concern for contralateral tumor or equivocal clinical examination [8].


Staging and Surveillance of Testicular Cancer. Variant 4: Surveillance of stage IA and IB nonseminoma testicular cancer. Diagnosed by orchiectomy. No clinical suspicion of recurrence. Bone Scan Whole Body Bone metastases from testicular cancer are uncommon. In one study, bone scan was able to detect metastases to the iliac bones ipsilateral to the testicular tumor before they were detectable by CT [12].


Staging and Surveillance of Testicular Cancer. CT Abdomen and Pelvis CT is the reference standard imaging test used for assessing the retroperitoneum for the presence of metastatic lymphadenopathy. CT is rapid, reproducible, and provides excellent imaging assessment of the para-aortic and paracaval regions [13-15]. Challenges related to CT are that many young men have little retroperitoneal fat, which may be an impediment for readers interpreting the study, and that CT cannot detect metastatic disease in lymph nodes of normal size. Additionally, inflammatory lymph nodes cannot be differentiated from those that are enlarged from metastases [16].


Staging and Surveillance of Testicular Cancer. It is important to recognize that a significant percentage of metastatic lymph nodes will be <1 cm, up to 60% in one series [24]. For this reason, some authors suggest using a cut-off value of 0.7 cm to 0.8 cm in testicular cancer at the expense of reduced specificity [24,25]. These cut-off values are for the short-axis measurement when assessing the likelihood of nodal disease (N0 versus N1 disease); however, when assessing the nodal burden, the lymph nodes should be measured in long axis (eg, N1 versus N2 and N3 disease) [6,25]. Two studies have also evaluated the value of nodal craniocaudal length or volume as risk factors for recurrence in testicular cancer [26,27]. Another study comparing lymph node measurements performed by expert radiologists, other observers, and a semiautomated process showed excellent correlation between measurements, indicating that the task of actually measuring lymph nodes, which can be time consuming and tedious, could potentially be delegated or automated in the future [28].


Staging and Surveillance of Testicular Cancer. Staging and Surveillance of Testicular Cancer The use of iodinated IV contrast media, as well as oral contrast media, may aid in detection of retroperitoneal lymph nodes, clarifying the adjacent normal anatomic structures including blood vessels and the duodenum [29].


Staging and Surveillance of Testicular Cancer. Surveillance protocols no longer include chest CT [30] and may eliminate pelvic CT, except in cases in which the pelvis is deemed high risk [53-55]. The number and frequency schedule of follow-up CT examinations of the abdomen and pelvis is variable [56]. Most recently, the 2021 NCCN guidelines recommends different intensity of follow-up for stage I pure seminoma testicular cancer and nonseminoma testicular cancer, which also depends on the presence or absence of risk factors for metastatic disease [8].


Staging and Surveillance of Testicular Cancer. CT Chest Although CT is more sensitive than radiography for detecting recurrent disease in the chest [30,31], this added sensitivity is offset by lower specificity and a higher false positive detection rate for abnormalities that are not metastatic [32]. Detection of mediastinal and hilar lymph nodes may be aided by the use of iodinated IV contrast media [33]. In patients with thoracic symptoms, the NCCN advises the use of CT chest for follow-up of patients with nonseminoma undergoing surveillance [8].


Staging and Surveillance of Testicular Cancer. FDG-PET/CT Whole Body FDG-PET has been used for staging and restaging patients with testicular cancer, but its incremental value in staging patients compared with CT or MRI has yet to be defined. For initial staging, PET may be slightly more sensitive than CT [34-39].


Staging and Surveillance of Testicular Cancer. MRI Abdomen and Pelvis MRI has also been studied for staging and surveillance of testicular cancer to identify metastatic retroperitoneal lymphadenopathy [41-46]. Limited evidence from single-institution studies indicates comparable efficacy to CT for detection of retroperitoneal lymphadenopathy, notably without the need for GBCAs [41,43].


Staging and Surveillance of Testicular Cancer. A limitation of the literature regarding MRI for detection of metastatic retroperitoneal lymphadenopathy is that the studies are older and do not incorporate DWI. DWI can substantially improve identification of lymph nodes; however, it is still limited by significant overlap between benign and malignant lymph nodes [6]. A study published in 2020 showed comparable accuracy between MRI, which included DWI and omitted GBCAs, and CT for detection of metastatic retroperitoneal lymph nodes in testicular germ-cell tumors [47].


Staging and Surveillance of Testicular Cancer. Radiography Chest The 2021 NCCN guidelines recommend chest radiography for surveillance of Stage I nonseminoma testicular cancer [8].


Staging and Surveillance of Testicular Cancer. US Abdomen and Retroperitoneum US of the abdomen and retroperitoneum to detect retroperitoneal lymph node metastases is less accurate and reproducible than CT, MRI, or PET/CT [50].


Staging and Surveillance of Testicular Cancer. Staging and Surveillance of Testicular Cancer Variant 5: Surveillance of stage IA and IB pure seminoma and nonseminoma testicular cancer. Diagnosed by orchiectomy. Suspected recurrence. Bone Scan Whole Body Bone metastases from testicular cancer are uncommon. In one study, bone scan was able to detect metastases to the iliac bones ipsilateral to the testicular tumor before they were detectable by CT [12].


Staging and Surveillance of Testicular Cancer. Lymph nodes >1 cm in short axis are highly suspicious for metastatic disease, particularly if they are located in the hilar regions of the kidney or in the para-aortic or caval areas (eg, testicular cancer landing zones). Various studies have established the accuracy of CT in detecting metastatic retroperitoneal lymph nodes from testicular cancer, which ranges from 73% to 97%, sensitivity ranges from 65% to 96%, and specificity from 81% to 100% [7,17-22]. Data also indicates that the accuracy of CT declines in patients with limited disease (eg, stage N1 and stage N2) and also if the upper limit of normal lymph node size is lowered [15,17,21]. Of note, most of these studies are relatively old and were performed using single-slice CT; however, limited newer data suggest similar accuracy using multi- slice CT compared with single-slice CT [23].


Staging and Surveillance of Testicular Cancer. The use of iodinated IV contrast media, as well as oral contrast media, may aid in detection of retroperitoneal lymph nodes, clarifying the adjacent normal anatomic structures including blood vessels and the duodenum [29].


Staging and Surveillance of Testicular Cancer. The number and frequency schedule of follow-up CT examinations of the abdomen and pelvis is variable [56]. Most recently, the 2021 NCCN guidelines recommends different intensity of follow-up for stage I pure seminoma testicular cancer and nonseminoma testicular cancer, which also depends on the presence or absence of risk factors for metastatic disease [8].


Staging and Surveillance of Testicular Cancer. CT Chest Although CT is more sensitive than radiography for detecting recurrent disease in the chest [30,31], this added sensitivity is offset by lower specificity and a higher false positive detection rate for abnormalities that are not metastatic [32]. Detection of mediastinal and hilar lymph nodes may be aided by the use of iodinated IV contrast media [33].


Staging and Surveillance of Testicular Cancer. Several studies indicate that chest radiography is sufficient when compared with CT for follow-up of stage I pure seminoma testicular cancers [30,32,49,54]. However, the 2021 NCCN guidelines advise the use of chest CT in both patients with Stage I pure seminoma or nonseminoma testicular cancer with thoracic symptoms [8].


Staging and Surveillance of Testicular Cancer. Staging and Surveillance of Testicular Cancer MRI Abdomen and Pelvis MRI has also been studied for staging and surveillance of testicular cancer to identify metastatic retroperitoneal lymphadenopathy [41-46]. Limited evidence from single-institution studies indicates comparable efficacy to CT for detection of retroperitoneal lymphadenopathy, notably without the need for GBCAs [41,43].


Staging and Surveillance of Testicular Cancer. A limitation of the literature regarding MRI for detection of metastatic retroperitoneal lymphadenopathy is that the studies are older and do not incorporate DWI. DWI can substantially improve identification of lymph nodes; however, it is still limited by significant overlap between benign and malignant lymph nodes [6]. A study published in 2020 showed comparable accuracy between MRI, which included DWI and omitted GBCAs, and CT for detection of metastatic retroperitoneal lymph nodes in testicular germ cell tumors [47].


Staging and Surveillance of Testicular Cancer. MRI Head MRI of the head is not recommended during the surveillance of pure seminoma testicular cancer unless the patient is symptomatic.


Staging and Surveillance of Testicular Cancer. Radiography Chest In pure seminoma testicular cancer under surveillance, studies have shown that lung relapses are rarely detected by chest radiography alone, with most relapses detected by abnormal serum markers or abdominal and pelvic CT scan [57-59], calling into question the value of chest radiography in surveillance of stage I pure seminoma testicular cancer. The 2021 NCCN guidelines recommend chest radiography for stage I pure seminoma testicular cancer patients undergoing surveillance as clinically indicated [8]. Chest radiography is recommended by the 2021 NCCN guidelines for stage I nonseminoma; in patients with thoracic symptoms, CT Chest is advised [8].


Staging and Surveillance of Testicular Cancer. Staging and Surveillance of Testicular Cancer Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch.acr.org/list. The appendix includes the strength of evidence assessment and the final rating round tabulations for each recommendation.


Staging and Surveillance of Testicular Cancer. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Staging and Surveillance of Testicular Cancer. Appropriateness Category Names and Definitions Relative Radiation Level Information Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, a relative radiation level (RRL) indication has been included for each imaging examination. The RRLs are based on effective dose, which is a radiation dose quantity that is used to estimate population total radiation risk associated with an imaging procedure. Patients in the pediatric age group are at inherently higher risk from exposure, because of both organ sensitivity and longer life expectancy (relevant to the long latency that appears to accompany radiation exposure). For these reasons, the RRL dose estimate ranges for pediatric examinations are lower as compared with those specified for adults (see Table below). Additional


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Introduction/Background Pneumonia is one of the most common acute infections and the single greatest infectious cause of death in children worldwide, accounting for 16% of all deaths in children under 5 years of age [1,2]. Properly recognizing, diagnosing, and treating pneumonia and its complications are of vital importance. Pneumonia can be defined clinically as the presence of fever and/or acute respiratory symptoms [3-5]. However, the clinical symptoms often lack sensitivity and specificity for the diagnosis of pneumonia [5]. Imaging plays a limited role in uncomplicated pneumonia and is primarily reserved for diagnosis of pneumonia in more severe presentations, including significant respiratory distress, hypoxemia, failed antibiotic therapy, or for suspected complications [3,6]. Resolution of radiographic findings may lag behind the clinical presentation [3,7], and imaging is not specific for the causative organism [6].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Community-acquired pneumonia in children is defined as the presence of signs and symptoms of pneumonia in a previously healthy child caused by an infection acquired outside of the hospital [3].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Hospital-acquired pneumonia is most commonly defined as pneumonia that develops after 48 hours of hospitalization that was not present at the time of admission [10]. Hospital-acquired pneumonia is the second most common nosocomial infection after bloodstream infections, and the most common of all infections acquired in intensive care units [10]. Ventilator-associated pneumonia is a subset of hospital-acquired pneumonia that occurs in mechanically ventilated children and can affect up to 12% of ventilated children [11]. A diagnosis of hospital- acquired pneumonia is based upon a new or progressive lung infiltrate along with clinical evidence that the infiltrate is of infectious origin, which includes the new onset of fever, purulent sputum, and leukocytosis [10].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. The frequency of complicated pneumonia is rising [6,12]. Pleural effusion or empyema, pneumothorax, lung abscess, bronchopleural fistula, and necrotizing pneumonia are rare complications of community-acquired pneumonia with an incidence rate above 13% in children hospitalized with pneumonia [9,13,14]. It is estimated that


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Reprint requests to: publications@acr.org


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Pneumonia in the Immunocompetent Child 1% of children with community-acquired pneumonia develop pleural effusions and effusions that are seen in 13% to 28% of hospitalized children [9,13,14]. Parapneumonic effusions often resolve with antibiotic therapy, but large effusions and empyemas may require percutaneous aspiration, fibrinolytics, surgical drainage, or thoracoscopy [4,15-18]. Bronchopleural fistula develops as a complication of pneumonia if lung necrosis extends to the pleura. Bronchopleural fistula is associated with higher morbidity [17,19] and can be diagnosed clinically by seeing air bubbles in the chest tube drainage [19].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Recurrent pneumonia is defined as at least two episodes of pneumonia in 1 year, or three episodes ever, with radiographic clearing of parenchymal opacities between episodes. Recurrent pneumonia occurs in 7.7% to 9% of children with community-acquired pneumonia [20]. Recurrent pneumonia can be nonlocalized (different location) or localized (same location). In the immunocompetent child, the differential considerations for nonlocalized pneumonia includes aspiration, asthma, bronchiectasis, underlying pulmonary parenchymal damage (eg, history of bronchopulmonary dysplasia), and mucociliary deficiency [13,21]. The role of imaging is to identify any underlying anatomic lung abnormality such as bronchiectasis. In the immunocompetent child, the main differential for localized recurrent pneumonia is localized airway narrowing from intrinsic (eg, foreign body) or extrinsic cause (eg, mass, lymphadenopathy), focal bronchiectasis, underlying congenital lung abnormality (eg, congenital pulmonary airway malformation and sequestrations), underlying pulmonary parenchymal damage (eg, with history of bronchopulmonary dysplasia), and aspiration [13,21].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. All elements are essential: 1) timing, 2) reconstructions/reformats, and 3) 3-D renderings. Standard CTs with contrast also include timing issues and recons/reformats. Only in CTA; however, is 3-D rendering a required element. This corresponds to the definitions that the CMS has applied to the Current Procedural Terminology codes.


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Discussion of Procedures by Variant Variant 1: Child. 3 months of age and older. Immunocompetent. Suspected uncomplicated community- acquired pneumonia in a well-appearing child who does not require hospitalization. Initial imaging. Radiography Chest Chest radiographs cannot reliably distinguish viral from bacterial community-acquired pneumonia and do not reliably distinguish among the various possible bacterial pathogens [4]. Chest radiographs performed in children with suspected acute lower respiratory tract infection lead to increased use of antibiotics in a clinic or emergency department setting; however, they have not been shown to affect hospitalization rates [23]. Some of the studies in this Cochran review have minor methodological flaws; however, this is the largest available systematic review and meta-analysis [23]. Therefore, the British Thoracic Society, the Pediatric Infectious Diseases Society, and the Infectious Diseases Society of America guidelines do not recommend routine radiographs for management of uncomplicated community-acquired pneumonia in nonhospitalized patients [3,4,24].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. CT Chest There is no relevant literature to support the use of CT as the initial imaging study in this clinical scenario.


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Pneumonia in the Immunocompetent Child MRI Chest There is no relevant literature to support the use of MRI as the initial imaging study in this clinical scenario.


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Variant 2: Child. 3 months of age and older. Immunocompetent. Community-acquired pneumonia that does not respond to initial outpatient treatment or requires hospital admission. Initial imaging. Radiography Chest Radiographs can be used to document the presence, size, and character of parenchymal infiltrates as well as to identify complications of pneumonia that may lead to interventions beyond antimicrobial agents and supportive medical therapy [3,24]. Frontal and lateral views of the chest are appropriate when evaluating for pneumonia in children with significant respiratory distress, hypoxemia, and failed antibiotic therapy, as suggested by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America [3,24,30]. Chest radiographs should be performed in select patients with prolonged fever and cough even in the absence of tachypnea or respiratory distress [3].


Pneumonia in the Immunocompetent Child


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. MRI Chest There is no relevant literature to support the use of MRI as the initial imaging study in this clinical scenario.


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Variant 3: Child. 3 months of age and older. Immunocompetent. Suspected hospital-acquired pneumonia. Initial imaging. Radiography Chest Findings of new or progressive lung opacity support the diagnosis of hospital-acquired pneumonia in the appropriate clinical circumstances [10]. However, a new lung opacity in an inpatient with fever, leukocytosis, or leukopenia and purulent secretions is neither highly sensitive nor specific for hospital-acquired pneumonia [10,11].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. US Chest There is no relevant literature to support the use of US as the initial imaging study in this clinical scenario.


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Variant 4: Child. Immunocompetent. Pneumonia complicated by suspected moderate or parapneumonic effusion by chest radiograph. Next imaging study. Radiography Chest Decubitus View Decubitus radiographs may be helpful to distinguish free-flowing pleural effusions from loculated collections [31]. However, radiographs can neither identify the type of fluid present nor be used to visualize the internal characteristics of the fluid [32]. In a study of adult patients, radiographs had a sensitivity of 39% and specificity of 85% compared with CT for presence of an effusion [33].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. CT Chest There is limited evidence that a noncontrast chest CT is useful in this clinical scenario. Even with intravenous (IV) contrast, it may be difficult to distinguish consolidated lung from visceral pleural enhancement [34]. Contrast- enhanced CT can also be used to quantify the amount of pleural fluid and can also demonstrate pleural thickening


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Pneumonia in the Immunocompetent Child and enhancement that is suggestive of empyema. CT has limited ability to characterize the internal characteristics of parapneumonic effusions (eg, fibrin strands, septations, and complex fluid) [31,34-37].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. US Chest US is the gold standard imaging for quantifying the size and identifying the internal characteristics of a pleural effusion. In a study of adult patients, US had a sensitivity of 92% and specificity of 93% compared with CT for presence of an effusion [33]. US can also be used to guide drainage of pleural fluid and complicated parapneumonic effusions [16,26,34,38]. US is superior to chest CT for effusion characterization (eg, fibrin strands, septations, and complex fluid) [31,34-36,39].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Variant 5: Child. Immunocompetent. Pneumonia complicated by suspected bronchopleural fistula by chest radiograph. Next imaging study. CT Chest CT chest without IV contrast can detect bronchopleural fistulae [45]. A direct sign on CT of a bronchopleural fistula is a fistulous tract between the bronchus or lung and pleural space. An indirect sign of a bronchopleural fistula is the presence of air bubbles beneath the bronchial stump or suspected fistula [45].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. CT chest with IV contrast can show the same findings as CT chest without IV contrast [45]. Additionally, CT chest with IV contrast can show important findings, such as necrotizing pneumonia, pulmonary abscess, and empyema that may be the underlying cause of the bronchopleural fistula [13,19,35,46-48]. There is no evidence directly comparing CT chest without IV contrast and CT chest with IV contrast in diagnosis of bronchopleural fistula.


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. MRI Chest There is no relevant literature supporting the use of MRI as the initial imaging study in this clinical scenario.


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Variant 6: Child. Immunocompetent. Pneumonia complicated by suspected lung abscess by chest radiograph. Next imaging study. CT Chest In the context of diagnosing necrotizing pneumonia or pulmonary abscess, contrast-enhanced CT is considered the gold standard for imaging [13,19,35,46,47]. CT chest with IV contrast can also differentiate between parenchymal and pleural processes [31]. There is no literature supporting the use of noncontrast CT in the evaluation of pulmonary abscess.


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. US Chest There is no literature that investigates the diagnostic accuracy of US in the setting of lung abscess. However, there is some literature that evaluates the effectiveness of US for differentiating between lung abscess and empyema, which is the main imaging mimic. This imaging differentiation is important because treatment for these conditions is often different, with abscess often treated with antibiotics and empyema often requiring drainage and antibiotics. In a reported series of 50 and 64 patients with lung abscesses, US was 94% to 96% sensitive and 96% to 100% specific for differentiating between lung abscess and empyema [49-51].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. MRI Chest There is limited evidence that MRI has similar sensitivity for abscess compared with CT [40-42]. There are some practical considerations for MRI as an initial imaging modality because clinically unstable patients can be difficult to manage in the MRI environment. If MRI is performed, IV contrast is recommended for the evaluation of lung


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Pneumonia in the Immunocompetent Child abscess [41]. Additionally, certain pediatric-aged patients typically require sedation, and sedation can result in atelectasis, which can make pleural effusion characterization more challenging.


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Variant 7: Child. 3 months of age and older. Immunocompetent. Recurrent nonlocalized pneumonia by chest radiograph. Next imaging study. CT Chest A noncontrast chest CT can be used to evaluate for an underlying pulmonary disease, such as postinfectious bronchiectasis, bronchopulmonary dysplasia, and findings such as bullae or bronchiectasis that may indicate a mucociliary deficiency [52]. There is no relevant literature regarding the use of contrast-enhanced CT in this clinical scenario.


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. US Chest There is no relevant literature regarding the use of US as the initial imaging study in this clinical scenario.


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. MRI Chest There is little evidence for MRI as a screening modality for causes of recurrent localized pneumonia, but it can be used to grade known or suspected disease. In one prospective study with 50 patients with noncystic fibrosis lung disease, MRI was equivalent to CT for grading central bronchiectasis and pulmonary consolidation but performed worse than CT for peripheral lung findings and for diagnosing emphysema and bullae [53]. There is no relevant literature regarding the use of contrast-enhanced MRI in this clinical scenario.


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Variant 8: Child. 3 months of age and older. Immunocompetent. Recurrent localized pneumonia by chest radiograph. Next imaging study. CT Chest CT chest without IV contrast can be used to diagnose anatomical abnormalities in the immunocompetent patient that could predispose children to recurrent localized infections, such as congenital lobar overinflation [54] or foreign bodies that could cause recurrent postobstructive pneumonia [13]. CT chest without IV contrast can also be used to evaluate underlying pulmonary disease like bronchopulmonary dysplasia [52].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Similar to CT chest without IV contrast, CT chest with IV contrast can be used to diagnose anatomical abnormalities in the immunocompetent patient that could predispose children to recurrent localized infections like congenital lobar overinflation [54], foreign bodies that could cause recurrent postobstructive pneumonia [13], and underlying pulmonary disease like bronchopulmonary dysplasia [52]. CT chest with IV contrast provides benefit over CT chest without IV contrast for diagnosing conditions such as bronchial tumors, congenital pulmonary airway malformation [54-58], pulmonary sequestration [21,54,55,59-63], and bronchopulmonary foregut malformations [54,55].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. CTA Chest CTA chest with IV contrast is especially helpful for presurgical planning, identifying feeding and draining vessels in patients with suspected pulmonary sequestration, and assessing for a vascular ring that may lead to tracheal narrowing [59,63]. In most cases, CTA of the chest with IV contrast is preferred over CT chest with IV contrast.


Pneumonia in the Immunocompetent Child


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. MRI Chest There is little evidence for MRI as a screening modality for causes of recurrent localized pneumonia, but it can be used to grade known or suspected disease. In one small prospective study, MRI was equivalent to CT for grading central bronchiectasis and pulmonary consolidations but performed worse than CT for peripheral lung findings and for diagnosing emphysema and bullae [53].


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. Pneumonia in the Immunocompetent Child Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch.acr.org/list. The appendix includes the strength of evidence assessment and rating round tabulations for each recommendation.


Pneumonia in the Immunocompetent Child

Pneumonia in the Immunocompetent Child. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Hematuria Child

Hematuria Child. Introduction/Background Hematuria is the presence of red blood cells in the urine, either visible to the eye (macroscopic hematuria) or as viewed under the microscope (microscopic hematuria). Detecting blood in the urine of a child may cause alarm to patients, parents, and physicians.


Hematuria Child

Hematuria Child. The next step is a thorough evaluation of the urine. Tea-colored urine and hematuria accompanied by proteinuria (>2+ by dip stick), red blood cell casts, and deformed red blood cells (best seen with phase contrast microscopy) suggest a glomerular source of hematuria (eg, glomerulonephritis) [6]. The presence of white cells and microorganisms within the urine clearly indicate the possibility of a urinary tract infection, which will direct care and imaging by a different set of criteria. Evaluation for hypercalciuria (such as a spot urine calcium/creatinine ratio) and a urine culture may be indicated. When concern for chronic kidney disease exists, basic laboratory metabolic screening in the initial evaluation should include blood urea nitrogen test, a serum creatinine test, and complete blood count with platelets. If suggested by the initial clinical workup, more advanced medical assessment for various causes of glomerulonephritis and vasculitis should be performed, and an audiogram and slit lamp examinations should be performed if there is suspicion for Alport syndrome [7-13].


Hematuria Child

Hematuria Child. Isolated hematuria (nonpainful, nontraumatic) Painful hematuria


Hematuria Child

Hematuria Child. In children with post-traumatic macroscopic hematuria, the role of imaging is to identify any evidence and the extent of renal or urinary tract injury. In other children, imaging has a role in identifying the cause of hematuria and to assess the size of the kidneys as an indicator of the chronicity of the renal disease and also as an assessment


Hematuria Child

Hematuria Child. Reprint requests to: publications@acr.org


Hematuria Child

Hematuria Child. Discussion of Procedures by Variant Isolated Hematuria (nonpainful, nontraumatic) Asymptomatic microscopic hematuria (usually defined as five or more red blood cells per high-powered field in either 2 or 3 of 3 consecutive urine specimens [16]) is a common entity, with an incidence estimated to be 0.25% to 1.0% in children 6 to 15 years of age [3-5,7-9,11,14,15].


Hematuria Child

Hematuria Child. CT Computed tomography (CT) is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria without proteinuria.


Hematuria Child

Hematuria Child. US US is generally not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria without proteinuria.


Hematuria Child

Hematuria Child. Microscopic hematuria is sometimes associated with hypercalciuria [19] and hyperuricosuria, and some authors advocate renal US to evaluate for renal calculi in these patients [14,20], although others have found little value in this technique [3]. In cases of persistent unexplained microhematuria, US may be used to evaluate for occult anatomic abnormalities (cystic renal disease, nutcracker syndrome, congenital anomalies, etc), although the yield of these examinations is low [7-9,11,14,21]. Isolated microscopic hematuria is very rarely the presenting scenario of Wilms tumor [3].


Hematuria Child

Hematuria Child. IVU Intravenous urography (IVU) is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria without proteinuria [14,21].


Hematuria Child

Hematuria Child. MRI Magnetic resonance imaging (MRI) is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria without proteinuria.


Hematuria Child

Hematuria Child. VCUG VCUG is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria without proteinuria.


Hematuria Child

Hematuria Child. Voiding Urosonography Voiding urosonography is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria without proteinuria.


Hematuria Child

Hematuria Child. Radiography Radiography (abdomen and pelvis [KUB]) is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria without proteinuria.


Hematuria Child

Hematuria Child. Variant 2: Child. Isolated microscopic hematuria (nonpainful, nontraumatic) with proteinuria. Initial imaging. While protein and blood in the urine can be harmless in some children, patients with both microscopic hematuria and leakage of protein into the urine (with or without hypertension and edema) are more likely to have glomerular renal disease and eventually develop progressive chronic kidney disease [22]. Imaging findings are usually not specific for any underlying pathology.


Hematuria Child

Hematuria Child. US Kasap et al [23] showed that glomerulonephritis is a frequent cause of increased renal cortical echogenicity in childhood. The kidneys also may be enlarged in the setting of acute glomerulonephritis. In long-standing glomerular kidney disease, the kidneys may become atrophic with altered corticomedullary differentiation. Finally, US can help assess the feasibility of percutaneous kidney biopsy and aid in preprocedural planning.


Hematuria Child

Hematuria Child. CT CT is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria with proteinuria.


Hematuria Child

Hematuria Child. IVU IVU is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria with proteinuria.


Hematuria Child

Hematuria Child. MRI MRI is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria with proteinuria.


Hematuria Child

Hematuria Child. Radiography Radiography (KUB) is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria with proteinuria.


Hematuria Child

Hematuria Child. VCUG VCUG is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria with proteinuria.


Hematuria Child

Hematuria Child. Voiding Urosonography Voiding urosonography is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria with proteinuria.


Hematuria Child

Hematuria Child. IVU IVU urography is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria with proteinuria.


Hematuria Child

Hematuria Child. Arteriography Arteriography is not appropriate in the initial evaluation of isolated nonpainful, nontraumatic hematuria with proteinuria.


Hematuria Child

Hematuria Child. Variant 3: Child. Isolated macroscopic hematuria (nonpainful, nontraumatic). Initial imaging. Isolated asymptomatic macroscopic hematuria is usually due to benign processes such as hypercalcuria and IgA nephropathy [4,19,24-26]. Imaging has a role to exclude nephrolithiasis, underlying urologic abnormalities, and rarely renal or bladder tumors.


Hematuria Child

Hematuria Child. Voiding Urosonography While voiding urosonography is usually not indicated in the evaluation of isolated macroscopic hematuria, and there is a paucity of literature to support its use, it is likely that voiding urosonography also can be used to assess for causes of hematuria that may be detected by VCUG.


Hematuria Child

Hematuria Child. CT CT is generally not indicated as a first-line test for isolated macroscopic hematuria. However, contrast-enhanced CT has a role in evaluation of renal mass diagnosed by US, and it may be considered in children with recurrent macroscopic hematuria with negative US and extensive clinical workup in the rare setting of suspected left renal vein obstruction (ie, nutcracker syndrome) [33]. Unenhanced CT may also be used to evaluate for suspected asymptomatic nephrolithiasis as a cause of hematuria in the setting of a negative US.


Hematuria Child

Hematuria Child. IVU Because the incidence of upper urinary tract urothelial neoplasia is extremely rare in children, IVU is not indicated in the initial evaluation of isolated macroscopic hematuria [14,34].


Hematuria Child

Hematuria Child. MRI MR is generally not indicated as the first-line test for isolated macroscopic hematuria. In the cases of suspected renal mass or nutcracker syndrome, MRI may be of value for further diagnosis [25,27-29,33,35-41].


Hematuria Child

Hematuria Child. Arteriography/Venography Arteriography and venography have no role in the initial evaluation of isolated macroscopic hematuria.


Hematuria Child

Hematuria Child. Radiography Radiography (KUB) is generally not appropriate in the initial evaluation of isolated nonpainful, nontraumatic isolated macroscopic hematuria. Radiography may have a limited role for detecting suspected asymptomatic nephrolithiasis as a cause of hematuria.


Hematuria Child

Hematuria Child. Variant 4: Child. Painful hematuria (nontraumatic). Suspected urolithiasis. Initial imaging. In the patient with abdominal pain and hematuria, the principal differential diagnosis is urolithiasis, although tumor and ureteropelvic junction (UPJ) obstruction should also be included. In young patients with genitourinary tract stone disease, the presenting symptoms may not be as classic as in adults, which in turn leads to uncertainty about the best imaging approach [42]. Interestingly, a number of pediatric patients with urolithiasis do not have hematuria [43]. While the incidence of pediatric stone disease is considerably lower than in adults, it is still commonly seen in busy pediatric practices [44]. Affected children may have a family history of nephrolithiasis or predisposing inborn metabolic disease [45,46]. While the literature provides general suggestions and guidelines, universal agreement regarding the imaging procedure of choice in suspected urolithiasis has not been reached.


Hematuria Child

Hematuria Child. CT CT There is good evidence in adults that CT is the most accurate imaging modality in the identification of stones and the quantification of stone burden, with sensitivity and specificity both well above 90% [44,47-55]. With proper techniques and newer image iterative reconstruction algorithms, the CT dose can be very low and lowered to less than that of a traditional IVU [44,56,57]. Limitations of radiography (eg, small stone size, obscuration of stones by bowel contents) and US (eg, small stone size, obscuration of a portion of the kidney by bowel gas, poor sonographic window) in children do not impair CT evaluation. CT may be particularly useful in the setting of painful hematuria, a negative kidney and bladder US examination, and high clinical suspicion for urolithiasis, particularly if detection would impact treatment.


Hematuria Child

Hematuria Child. US US of the kidneys and bladder has limited sensitivity in detection of renal and ureteral stones. Palmer et al [49] reported that US found 75% of all urinary tract stones, although US found only 38% of stones within the ureter. Similarly, Oner et al [48] showed that US correctly found stones in 78% of patients, although it only found 25% of ureteral stones.


Hematuria Child

Hematuria Child. The same study by Masch et al [63] showed that US has a sensitivity of only 31% for renal stone detection if an echogenic focus, posterior acoustic shadowing, and twinkling artifact are all required findings to make a diagnosis. US is still recommended by some as a first-line screening test and, if positive, can then direct patient management [48,49,64], with the caveat that a negative US does not exclude stone disease [49].


Hematuria Child

Hematuria Child. Radiography Levine et al [47] in a study of 178 adult and pediatric patients found radiographs had a 59% sensitivity for stone detection.


Hematuria Child

Hematuria Child. IVU IVU is seldom indicated in children as an initial examination, although a limited study may provide information about stone position, degree of urinary tract obstruction, and movement after initial diagnosis.


Hematuria Child

Hematuria Child. MRI MRI is not appropriate in the initial evaluation of painful hematuria and suspected urolithiasis.


Hematuria Child

Hematuria Child. VCUG VCUG is not appropriate in the initial evaluation of painful hematuria and suspected urolithiasis.


Hematuria Child

Hematuria Child. Voiding Urosonography Voiding urosonography is not appropriate in the initial evaluation of painful hematuria and suspected urolithiasis.


Hematuria Child

Hematuria Child. Arteriography Renal arteriography is not appropriate in the evaluation of painful hematuria and suspected urolithiasis.


Hematuria Child

Hematuria Child. 8 If the abdominal and pelvic CT is used as the criterion standard for identifying urologic trauma in children, the microscopic urinalysis has moderate discriminatory power to predict urologic injury [77].


Hematuria Child

Hematuria Child. Patients with gross hematuria and pelvic fractures are at high risk for bladder rupture [81,82]. The conventional fluoroscopic cystogram requires moving the patient to another imaging suite. There is evidence that CT cystography (ie, CT of the pelvis performed after retrograde distention of the urinary bladder with iodinated contrast material) is an accurate method of evaluation, with the advantage that the patient need not be moved from the CT scanner [81-83]. Images are to be obtained with a contrast-filled bladder and may be obtained after drainage, although one study in adults suggests that postvoid images may be unnecessary [81]. Multiplanar reformatted images may help in diagnosis [84].


Hematuria Child

Hematuria Child. Retrograde Urethrography Patients with blood at the urethral meatus, especially if associated with pelvic fractures or straddle injury, are at risk for urethral injury and disruption. These patients should undergo retrograde urethrography prior to bladder catheter placement [76] and may warrant a cystogram to exclude concomitant bladder injury.


Hematuria Child

Hematuria Child. Radiography In general, radiography is not appropriate in the initial evaluation of traumatic macroscopic hematuria. Radiographs of the pelvis may reveal pelvic fractures and, in the setting of macroscopic hematuria, raise the possibility of bladder or urethral injury.


Hematuria Child

Hematuria Child. VCUG VCUG is not appropriate for the initial evaluation of traumatic macroscopic hematuria. If there is concern for urethral injury, dedicated retrograde urethrography is a more appropriate initial imaging test. If there is concern for bladder injury, dedicated CT cystography is a more appropriate initial imaging test.


Hematuria Child

Hematuria Child. Voiding Urosonography Voiding urosonography is not appropriate for the initial evaluation of traumatic macroscopic hematuria. If there is concern for urethral injury, dedicated retrograde urethrography is a more appropriate initial imaging test. If there is concern for bladder injury, dedicated CT cystography is a more appropriate initial imaging test.


Hematuria Child

Hematuria Child. Arteriography Arteriography is not appropriate in the initial evaluation of traumatic macroscopic hematuria. In the setting of hemodynamic instability and renal or pelvic artery extravasation detected by CT, arteriography may be used to guide endovascular embolization. Arteriography may also be used to guide the treatment of CT-detected post- traumatic pseudoaneurysms and arteriovenous fistulas [91,92].


Hematuria Child

Hematuria Child. MRI MRI is not appropriate in the initial evaluation of traumatic macroscopic hematuria.


Hematuria Child

Hematuria Child. CT (including CT cystography) Unlike in adults, no firm consensus has been reached on the best guidelines for imaging in pediatric blunt abdominopelvic trauma and microscopic hematuria [71,79]. For adult patients with isolated microscopic hematuria without coexistent injury, there is evidence that renal imaging with CT is unlikely to disclose clinically significant findings [67,70-72]. However, the evidence for that in children is limited. A study by Nguyen and Das [71] found that 12 of 32 (37.5%) with grades 2 to 5 renal injuries did not have macroscopic hematuria; 8 had microscopic hematuria, and 4 had normal urinalyses. Thus, the authors concluded that significant renal injuries can be encountered in the setting of microscopic hematuria, and the decision to perform CT should be based on history and mechanism of injury and not urinalysis alone. Children with congenital renal abnormalities (eg, UPJ obstruction), multiorgan injury, history of deceleration injury, localized flank pain, and ecchymosis should undergo CT imaging to evaluate for renal injury, even when gross hematuria is not present. Renal injury without macroscopic hematuria can also be found in a child with falling hemoglobin or a hemodynamic instability [70,72]. Microscopic hematuria has also been combined with other clinical variables to create prediction rules for identifying children with intra-abdominal injuries following blunt abdominal trauma [95].


Hematuria Child

Hematuria Child. Patients with hematuria, even microscopic, in the setting of pelvic fractures are at risk for bladder injury. Dedicated CT cystography is an accurate method of evaluation of bladder injury [81-83].


Hematuria Child

Hematuria Child. US There is little evidence to support the use of US in the initial evaluation of traumatic microscopic hematuria. That said, renal US may be considered in cases of pediatric renal trauma that might otherwise not be imaged with CT because of low levels of hematuria to provide a screening tool for the occult vascular injury, pre-existing congenital anomaly, or the unusual major renal injury without significant hematuria.


Hematuria Child

Hematuria Child. Arteriography Renal arteriography is not appropriate in the initial evaluation of traumatic microscopic hematuria.


Hematuria Child

Hematuria Child. Radiography Radiography (KUB) is not appropriate in the initial evaluation of traumatic microscopic hematuria.


Hematuria Child

Hematuria Child. VCUG VCUG is not appropriate in the initial evaluation of traumatic microscopic hematuria. If there is concern for urethral injury, dedicated retrograde urethrography is a more appropriate initial imaging test. If there is concern for bladder injury, dedicated CT cystography is a more appropriate initial imaging test.


Hematuria Child

Hematuria Child. Voiding Urosonography Voiding urosonography is not appropriate in the initial evaluation of traumatic microscopic hematuria. If there is concern for urethral injury, dedicated retrograde urethrography is a more appropriate initial imaging test. If there is concern for bladder injury, dedicated CT cystography is a more appropriate initial imaging test.


Hematuria Child

Hematuria Child. Retrograde urethrography Retrograde urethrography is not appropriate in the initial evaluation of traumatic microscopic hematuria, unless there is high clinical suspicion for urethral injury (eg, pelvic fractures or known straddle injury).


Hematuria Child

Hematuria Child. IVU IVU is not appropriate in the initial evaluation of traumatic microscopic hematuria.


Hematuria Child

Hematuria Child. MRI MRI is not appropriate in the initial evaluation of traumatic microscopic hematuria.


Hematuria Child

Hematuria Child. Although there are references that report on studies with design limitations, 8 well-designed or good-quality studies provide good evidence.


Hematuria Child

Hematuria Child. Appropriateness Category Names and Definitions Relative Radiation Level Information Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, a relative radiation level (RRL) indication has been included for each imaging examination. The RRLs are based on effective dose, which is a radiation dose quantity that is used to estimate


Hematuria Child

Hematuria Child. Supporting Documents For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Introduction/Background Although the true prevalence of mediastinal masses is not known, a 0.9% prevalence of anterior or prevascular mediastinal masses was found among the 2,571 chest CTs of the 51% female cohort of the Framingham Heart Study, with a mean age of 59 years [1]. A 0.73% prevalence of prevascular mediastinal nodules was found on the chest CTs of a 63% male cohort (n = 56,358 participants), with a mean age of 52 years undergoing baseline low- dose chest CT for routine health surveillance [2]. A higher 4% prevalence of mediastinal masses was found on 589 CT pulmonary angiograms in a 63% female cohort with a mean age of 53 years [3]. On baseline lung cancer screening in the Early Lung Cancer Action Project, a 0.77% mediastinal mass prevalence was found in a cohort of 9,263 patients that was 51% female and had a median age of 65 years [4].


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. The classic imaging approach to mediastinal mass evaluation found on radiography has generally entailed a step- wise progression from chest radiography to CT [12-15] to diagnostic intervention when needed [16,17], with or without an intervening PET/CT. However, more recent recognition of the long-literature-supported ability of MRI to characterize tissue and add diagnostic specificity [18-23], prevent unnecessary biopsy and surgery [24-26], and modify and guide the approach to biopsy and surgery [27] has moved MRI into a valued position in terms of workup and triage of these lesions [28-33].


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization.


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Reprint requests to: publications@acr.org


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Imaging of Mediastinal Masses


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. OR Discussion of Procedures by Variant Variant 1: Clinically suspected mediastinal mass. Initial imaging. CT Chest Cross-sectional imaging can more definitively localize a lesion to a mediastinal compartment than chest radiography. Further tissue characterization of mediastinal masses beyond chest radiography is achievable by CT which can demonstrate and distinguish not only calcium and macroscopic fat but also water attenuation fluid, permitting noninvasive diagnosis of many mature teratomas [40]. Pre- and postcontrast conventional CT or dual- energy CT can show enhancing cellular components of lesions [41,42]; however, the soft-tissue contrast of CT is sometimes insufficient. For example, benign hyperattenuating thymic cysts on CT can be misinterpreted as thymomas, leading to unnecessary thymectomy [24]. Not infrequently, a mediastinal lesion is indeterminate by CT and requires further workup.


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. CT is superior to chest radiography for detection of invasion of the mass across tissue planes, secondary to its higher contrast resolution. Invasion of adjacent large blood vessels and the chest wall is important to identify, as it is associated with a higher probability of incomplete surgical resection of primary malignant mediastinal masses [43]. In addition, it can direct surgery when still planned and, in other cases, direct toward other forms of clinical management, including neoadjuvant chemotherapy and radiation therapy. As a supplement to static assessment of tissue plane transgression, which can be difficult, dynamic CT [44] during free-breathing or cinematic cardiac gating can be performed to assess movement of the mass relative to adjacent structures and confirm or exclude adherence of the mass to adjacent structures; however, dynamic MRI during free-breathing can accomplish the same task [45- 48]. MRI remains superior to CT for detection of invasion of the mass across tissue planes, including the chest wall and diaphragm, and involvement of neurovascular structures, secondary to its higher soft-tissue contrast [49-52].


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. FDG-PET/CT Skull Base to Mid-Thigh Fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT offers that of conventional CT in the initial assessment of mediastinal masses [53], with the exception of its use for primary mediastinal lymphoma staging and surveillance and detection of metastatic lymphadenopathy, the latter of which is not within the scope of this topic. With regard to prevascular mediastinal masses, a negative FDG-PET/CT has been shown to be helpful in excluding malignancy; however, a positive FDG-PET/CT has little value for discrimination between benign and malignant lesions [53]. The frequent FDG-PET/CT avidity of normal and hyperplastic thymus [54] is a confounder in FDG-PET/CT assessment of the prevascular mediastinum. Benign


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Imaging of Mediastinal Masses thymic cysts can also be FDG-PET/CT-avid [42]. Combined use of FDG-PET/CT and dynamic contrast-enhanced (DCE) MRI has been shown to be helpful to distinguish prevascular mediastinal solid tumors from one another [55]. Higher standardized uptake values (SUVs) on FDG-PET/CT are more frequently found in high-risk thymoma, thymic carcinoma, and lymphoma than in low-risk thymoma [55-57].


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Cross-sectional imaging by MRI remains superior to CT for detection of invasion of the mass across tissue planes, including the chest wall and diaphragm, and involvement of neurovascular structures, secondary to its higher soft- tissue contrast [48-52]. As a supplement to static assessment of tissue plane transgression, dynamic MRI [45-48] during free-breathing or cinematic cardiac gating can be performed to assess movement of the mass relative to adjacent structures, confirm or exclude adherence of the mass to adjacent structures, and observe diaphragmatic motion in real time [80-84]; paradoxical motion or lack of motion can indicate phrenic nerve involvement by the mediastinal mass, without the need to perform a subsequent fluoroscopic sniff test.


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Radiography Chest When there is a clinically suspected mediastinal mass, it is reasonable to perform a chest radiograph as an initial imaging step. Chest radiography can help localize a mass to a specific mediastinal compartment and thereby narrow the differential diagnosis [85-88]. It can also show any associated pleural, lung, and bone findings to some extent. Chest radiography offers limited assistance regarding tissue characterization of mediastinal masses, with the exception of its occasional demonstration of calcium within a lesion.


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. US Chest There is little relevant literature to support the use of ultrasound (US) in the initial evaluation of a clinically suspected mediastinal mass. Because of the limited transthoracic sonographic window, US would not be useful to screen for a clinically suspected mediastinal mass. Transthoracic US can be used to evaluate mediastinal masses, when accessible to the sonographic window, delineating their size, location, cystic versus solid nature, relationship to important vascular structures, and vascularity, with some diagnostic potential [89]. Endoscopic US can similarly evaluate mediastinal masses when encompassed in the sonographic window [90]. The tissue characterization capability of US is inferior to MRI but not to CT.


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Image-Guided Transthoracic Needle Biopsy Image-guided transthoracic needle biopsy is not a form of initial imaging.


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Variant 2: Indeterminate mediastinal mass on radiography. Next imaging study. CT Chest Cross-sectional imaging, by its very nature, can more definitively localize a lesion to a mediastinal compartment than chest radiography. Further tissue characterization of mediastinal masses beyond chest radiography is achievable by CT, which can demonstrate and distinguish not only calcium and macroscopic fat but also water attenuation fluid, thus permitting noninvasive diagnosis of many mature teratomas [40]. Pre- and postcontrast


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. conventional CT or dual-energy CT can show enhancing, cellular components of lesions [41,42]; however, the soft- tissue contrast of CT is sometimes insufficient. For example, benign hyperattenuating thymic cysts on CT can be misinterpreted as thymomas, leading to unnecessary thymectomy [24]. Not infrequently, a mediastinal lesion is indeterminate by CT and requires further workup.


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. CT is superior to chest radiography for detection of invasion of the mass across tissue planes, secondary to its higher contrast resolution. Invasion of adjacent large blood vessels and the chest wall is important to identify, as it is associated with a higher probability of incomplete surgical resection of primary malignant mediastinal masses [43]. In addition, it can direct surgery when still planned, and in other cases, direct toward other forms of clinical management, including neoadjuvant chemotherapy and radiation therapy. As a supplement to static assessment of tissue plane transgression, which can be difficult, dynamic CT [44] during free-breathing or cinematic cardiac gating can be performed to assess movement of the mass relative to adjacent structures and to confirm or exclude adherence of the mass to adjacent structures; however, dynamic MRI during free-breathing can accomplish the same task [45- 48]. MRI remains superior to CT for detection of invasion of the mass across tissue planes, including the chest wall and diaphragm, and involvement of neurovascular structures, secondary to its higher soft-tissue contrast [49-52].


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT offers limited additional value beyond that of conventional CT in the assessment of mediastinal masses [53], with the exception of its use for primary mediastinal lymphoma staging and surveillance and detection of metastatic lymphadenopathy, the latter of which is not within the scope of this topic. FDG-PET/CT has become the standard for staging and assessment of treatment response for lymphomas that are FDG-PET-avid at baseline or at the time recurrence [91-97]. A caveat is that although a negative surveillance FDG-PET/CT is reassuring of a good outcome, a positive FDG-PET/CT can be misleading, as it does not always implicate residual or recurrent lymphoma [96,98]. CT and MRI can be used for surveillance of lymphadenopathy when the metabolic activity of the lymphadenopathy is not of interest and when allowed within a clinical protocol. With regard to prevascular mediastinal masses, a negative FDG-PET/CT has been shown to be helpful in excluding malignancy; however, a positive FDG-PET/CT has little value for discrimination between benign and malignant lesions [53]. The frequent FDG-PET/CT avidity of normal and hyperplastic thymus [54] is a confounder in FDG-PET/CT assessment of the prevascular mediastinum. Benign thymic cysts can also be FDG-PET/CT-avid [42]. Combined use of FDG-PET/CT and DCE MRI has been shown to be helpful to distinguish prevascular mediastinal solid tumors from one another [55]. Higher SUVs on FDG-PET/CT are more frequently found in high-risk thymoma, thymic carcinoma, and lymphoma than in low-risk thymoma [55-57]. FDG-PET/CT appears to be more sensitive than CT alone for detection of mediastinal recurrence of thymoma [99].


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Cross-sectional imaging by MRI remains superior to CT for detection of invasion of the mass across tissue planes, including the chest wall and diaphragm, and involvement of neurovascular structures, secondary to its higher soft-


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. tissue contrast [48-52]. As a supplement to static assessment of tissue plane transgression, dynamic MRI [45-48] during free-breathing or cinematic cardiac gating can be performed to assess movement of the mass relative to adjacent structures, confirm or exclude adherence of the mass to adjacent structures, and observe diaphragmatic motion in real time [80-84]; paradoxical motion or lack of motion can indicate phrenic nerve involvement by the mediastinal mass, without the need to perform a subsequent fluoroscopic sniff test.


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. US Chest Unless a mediastinal mass found on chest radiography is deemed fully accessible by transthoracic US, there is little relevant literature to support its use as the next step. Transthoracic US can be used to evaluate mediastinal masses, when accessible to the sonographic window, delineating their size, location, cystic versus solid nature, relationship to important vascular structures, and vascularity, with some diagnostic potential [89]. Endoscopic US can similarly evaluate mediastinal masses when encompassed in the sonographic window [90]. The tissue characterization capability of US is inferior to MRI but not to CT.


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Image-Guided Transthoracic Needle Biopsy Image-guided transthoracic needle biopsy would seldom be performed without a preceding cross-sectional imaging study.


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Variant 3: Indeterminate mediastinal mass on CT. Next imaging study. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT offers limited additional value beyond that of conventional CT in the assessment of mediastinal masses [53], with the exception of its use for primary mediastinal lymphoma staging and surveillance and detection of metastatic lymphadenopathy, the latter of which is not within the scope of this topic. FDG-PET/CT has become the standard for staging and assessment of treatment response for lymphomas that are FDG-PET-avid at baseline or at the time recurrence [91-97]. A caveat is that although a negative surveillance FDG-PET/CT is reassuring of a good outcome, a positive FDG-PET/CT can be misleading, as it does not always implicate residual or recurrent lymphoma [96,98]. CT and MRI can be used for surveillance of lymphadenopathy, when the metabolic activity of the lymphadenopathy is not of interest and when allowed within a clinical protocol. With regard to prevascular mediastinal masses, a negative FDG-PET/CT has been shown to be helpful in excluding malignancy; however, a positive FDG-PET/CT has little value for discrimination between benign and malignant lesions [53]. The frequent FDG-PET/CT avidity of normal and hyperplastic thymus [54] is a confounder in FDG-PET/CT assessment of the prevascular mediastinum. Benign thymic cysts can also be FDG-PET/CT-avid [42]. Combined use of FDG-PET/CT and DCE MRI has been shown to be helpful to distinguish prevascular mediastinal solid tumors from one another [55]. Higher SUVs on FDG-PET/CT are more frequently found in high-risk thymoma, thymic carcinoma, and lymphoma than in low-risk thymoma [55-57]. FDG-PET/CT appears to be more sensitive than CT alone for detection of mediastinal recurrence of thymoma [99].


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Imaging of Mediastinal Masses


Imaging of Mediastinal Masses


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. US Chest There is little relevant literature to support US of an indeterminate mediastinal mass on CT. Transthoracic US can be used to evaluate mediastinal masses when accessible to the sonographic window, delineating their size, location, cystic versus solid nature, relationship to important vascular structures, and vascularity, with some diagnostic potential [89]. Endoscopic US can similarly evaluate mediastinal masses when encompassed in the sonographic window [90]. The tissue characterization capability of US is inferior to MRI but not to CT.


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Image-Guided Transthoracic Needle Biopsy CT-guided percutaneous needle and core biopsy of accessible mediastinal masses has been shown to be safe and to have a good diagnostic yield, with core biopsy more effective than fine-needle aspiration. Biopsy was more frequently diagnostic for TETs than for lymphoma [101-104]. A retrospective study of 293 consecutive CT-guided mediastinal biopsies performed in 285 patients showed an overall diagnostic yield of 87% for mediastinal masses with a mean size of 5.3 cm and 57% for residual masses at the site of treated lymphoma [101]. Another retrospective study of 52 patients reported a 77% diagnostic yield for needle biopsy of mediastinal masses with a mean size of 6.9 cm [102]. When the distinction of TETs from lymphoma cannot be definitively made by imaging, image-guided biopsy has a role. PET/CT guidance for biopsy reportedly yields no diagnostic advantage [104]. When the lesion is visible within the sonographic window, transthoracic US-guided biopsy of mediastinal masses is also feasible, with color Doppler and contrast-enhanced sonographic techniques providing additional value [105-108] and with core biopsy more effective than fine-needle aspiration. Endoscopic biopsy of mediastinal masses is also feasible and effective, although not in the purview of this topic [109]. DWI MR may be helpful in directing CT-guided biopsy toward sites of higher cellularity and diagnostic yield [110], as may DCE MRI with postprocessed subtraction. MR- guided percutaneous needle biopsy has also been shown to be safe and diagnostically accurate [111].


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Radiography Chest After cross-sectional imaging has been performed for mediastinal mass evaluation, there is seldom a role for chest radiography.


Imaging of Mediastinal Masses

Imaging of Mediastinal Masses. Variant 4: Indeterminate mediastinal mass on FDG-PET/CT. Next imaging study. CT Chest After FDG-PET/CT has been performed for mediastinal mass evaluation, there is seldom a role for chest CT.