Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. Suspected Pulmonary Embolism Arteriography Pulmonary with Right Heart Catheterization Pulmonary angiography, including right heart catheterization and measurement of pulmonary artery and right heart pressures, is almost never used as a first-line test for PE, although it had historic diagnostic use [17-19] before it was supplanted by CTPA. The overall accuracy of catheter pulmonary angiography is likely to be inferior to CTPA. The role of angiography, when therapy such as pulmonary embolectomy is performed, is not within the scope of this document. This is in keeping with evidence suggesting that advanced imaging is not supported for patients included in Variant 1 [8,12-16].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. MRA Pulmonary Arteries Without and With IV Contrast The literature does not support the use of MR angiography (MRA) pulmonary arteries without and with IV contrast for the evaluation of suspected PE for patients with low to intermediate probability and negative D-dimer [8,12- 16].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. MRA Pulmonary Arteries Without IV Contrast The literature does not support the use of MRA pulmonary arteries without IV contrast for the evaluation of suspected PE for patients with low to intermediate probability and negative D-dimer [8,12-16].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. US Duplex Doppler Lower Extremity The literature does not support the use of ultrasound (US) duplex Doppler lower extremity for the evaluation of suspected PE for patients with low to intermediate probability and negative D-dimer [8,12-16].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. US Echocardiography Transesophageal The literature does not support the use of US echocardiography transesophageal for the evaluation of suspected PE for patients with low to intermediate probability and negative D-dimer [8,12-16].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. US Echocardiography Transthoracic Resting The literature does not support the use of US echocardiography transthoracic resting for the evaluation of suspected PE for patients with low to intermediate probability and negative D-dimer [8,12-16].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. V/Q Scan Lung The literature does not support the use of V/Q scan lung for the evaluation of suspected PE for patients with low to intermediate probability and negative D-dimer [8,12-16].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. CT Chest With IV Contrast There is no relevant literature to support the use of CT chest with IV contrast to assess PE in patients with low or intermediate probability with positive D-dimer. When IV contrast is given during the CT acquisition, the study should be performed as a CTPA.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. CT Chest Without and With IV Contrast There is no relevant literature to support the use of CT chest without and with IV contrast to assess PE in patients with low or intermediate probability with positive D-dimer. When IV contrast is given during the CT acquisition, the study should be performed as a CTPA.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. CT Chest Without IV Contrast There is no relevant literature to support the use of CT chest without IV contrast to assess PE in patients with low or intermediate probability with positive D-dimer.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. CTA Chest With IV Contrast with CTV Lower Extremities Older literature shows that the field of view for CTA can be extended to include the lower extremities so that both the pulmonary arteries and the deep veins of the leg can be imaged during the same imaging session [25,26]. However, this protocol is very rarely used at present, owing to the accuracy of performing US for DVT and the increased burden of contrast and radiation for the associated extended craniocaudal field of view [27].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. MRA Pulmonary Arteries Without IV Contrast Noncontrast MRA sequences alone for PE have been reported but remain investigational [41,43,44]. There is limited relevant literature to support the use of noncontrast MRA for suspected PE, low or intermediate pretest probability with a positive D-dimer.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. US Duplex Doppler Lower Extremity Compression US with Doppler flow studies are used to evaluate for peripheral DVT [45,46] and may be useful for patients who do not have a high likelihood of PE, particularly if the patient has symptoms of extremity DVT. The presence of DVT does not indicate the presence of PE, but it increases the likelihood. A negative extremity US study does not exclude PE, although it significantly decreases its likelihood [47-49].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism

Suspected Pulmonary Embolism PCAs. Suspected Pulmonary Embolism


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. will undergo CTPA to identify a filling defect in the diagnosis of PE [51]. Risk stratification for right ventricular failure when there is a positive CTPA [52-57] is commonly used, but this clinical situation (after a diagnosis of PE) is not within the scope of this document.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. V/Q Scan Lung The use of V/Q scans has considerably diminished with the widespread use of CTPA. Imaging protocols have evolved [10,58,59], and in some cases, perfusion imaging alone can be performed. The high negative predictive value of a normal V/Q scan has been confirmed by several studies, including a large outcome study [60]. Among the weaknesses of V/Q scanning are the high proportion of nondiagnostic results and the inability to provide an alternative diagnosis [1,58]. Abnormal regional lung perfusion may suggest the diagnosis of PE, but it is not specific. Findings require correlation with ventilation studies or other imaging. Investigators have studied single- photon emission CT (SPECT) to improve the sensitivity and specificity of V/Q scintigraphy [61]. The addition of CT to SPECT enables V/Q detection of conditions other than PE (such as radiation therapy induced changes, emphysema, and extrinsic vascular compression from conditions such as neoplasm or mediastinal adenopathy). However, this use remains experimental, and it is not rated as a separate imaging study.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. CT Chest With IV Contrast There is no relevant literature to support the use of other imaging protocols when CTPA is performed for PE. When IV contrast is given during the CT acquisition, the study should be performed as a CTPA.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. CT Chest Without and With IV Contrast There is no relevant literature to support CT chest without and with IV contrast for suspected PE, high pretest probability. When IV contrast is given during the CT acquisition, the study should be performed as a CTPA.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. CT Chest Without IV Contrast There is no relevant literature to support CT chest without IV contrast for suspected PE, high pretest probability.


Suspected Pulmonary Embolism PCAs


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. Arteriography Pulmonary with Right Heart Catheterization Pulmonary angiography, including right heart catheterization and measurement of pulmonary artery and right heart pressures, is almost never used as a first-line test for PE, although it had historic diagnostic use [17-19] before it was supplanted by CTPA. The overall accuracy of catheter pulmonary angiography is likely to be inferior to CTPA. The role of angiography, when therapy such as pulmonary embolectomy is performed, is not within the scope of this document. This invasive procedure has an estimated morbidity and mortality of 3.5% to 6% and 0.2% to 0.5%, respectively [32,33].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. MRA Pulmonary Arteries Without and With IV Contrast MRA can identify emboli in the central and segmental pulmonary arteries [34-37] among patients with low or intermediate probability with positive D-dimer [38]. However, limitations were identified by the PIOPED III trial


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. MRA Pulmonary Arteries Without IV Contrast Noncontrast MRA sequences alone for PE have been reported but remain investigational [43]. There is limited literature to support the use of noncontrast MRA of the pulmonary arteries for the evaluation of PE [24,34].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. US Duplex Doppler Lower Extremity Compression US may be useful for patients who do not have a high likelihood of PE, particularly if the patient has symptoms of extremity DVT. Compression US with Doppler flow studies are used to evaluate for peripheral DVT. US studies include duplex Doppler with leg compression and continuous-wave Doppler [45,46]. The presence of DVT does not indicate the presence of PE, but it increases the likelihood. A negative extremity US study does not exclude PE, although it significantly decreases its likelihood [47-49].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. V/Q Scan Lung The use of V/Q scans has considerably diminished with the widespread use of CTPA. Imaging protocols have evolved [10,58,59], and in some cases, perfusion imaging alone can be performed. The high negative predictive value of a normal V/Q scan has been confirmed by several studies, including a large outcome study [60]. Among the weaknesses of V/Q scanning are the high proportion of nondiagnostic results and the inability to provide alternative diagnosis [1,58]. Abnormal regional lung perfusion may suggest the diagnosis of PE, but it is not specific. Findings require correlation with ventilation studies or other imaging. Investigators have studied SPECT to improve the sensitivity and specificity of V/Q scintigraphy [61]. The addition of CT to SPECT enables V/Q detection of conditions other than PE (such as radiation therapy induced changes, emphysema, and extrinsic vascular compression from conditions such as neoplasm or mediastinal adenopathy). However, this use remains experimental, and it is not rated as a separate imaging study.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. Variant 4: Suspected pulmonary embolism. Pregnant patient. Initial imaging. Pregnancy frequently alters the diagnostic strategy for patients with clinically suspected PE, and thus it is considered as a separate variant. For guidance on pregnant patients, please refer to the Safety Considerations in Pregnant Patients section below.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. Suspected Pulmonary Embolism Radiography Chest Although radiographs are neither sensitive nor specific, the role in pregnancy becomes more relevant when compared to the other variants. The rationale is that an alternative diagnosis may be found, and for patients without clinical evidence of lower extremity DVT, radiography can inform the choice between CTPA and V/Q scanning as a second imaging test.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. CTPA Although the CTPA acquisition may be modified [62-64] for the physiology of pregnancy, CTPA is commonly performed. In a study involving pregnant women with high pretest probability and those with intermediate probability and positive D-dimer followed by negative bilateral lower extremity US who were evaluated with CTPA, the positive rate was 5.7% (19 of 332), and the indeterminate rate was 6.9% (23 of 332) [65].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. CT Chest With IV Contrast When IV contrast is given during the CT acquisition, the study should be performed as a CTPA. There is no relevant literature to support the use of CT chest with IV contrast for suspected PE in a pregnant patient.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. CT Chest Without and With IV Contrast When IV contrast is given during the CT acquisition, the preferred protocol is CTPA. There is no relevant literature to support the use of CT chest without and with IV contrast for suspected PE in a pregnant patient.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. CT Chest Without IV Contrast There is no relevant literature to support the use of CT chest without IV contrast for suspected PE in a pregnant patient.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. CTA Chest With IV Contrast with CTV Lower Extremities Older literature shows that the field of view for CTA can be extended to include the lower extremities so that both the pulmonary arteries and the deep veins of the leg can be imaged during the same imaging session [25,26]. However, this protocol is very rarely used at present, owing to the accuracy of performing US for DVT and the increased burden of contrast and radiation for the associated extended craniocaudal field of view [27].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. CTA Triple Rule Out There is no relevant literature to support the use of CTA triple rule out for suspected PE in a pregnant patient.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. Arteriography Pulmonary with Right Heart Catheterization There is no relevant literature to support diagnostic catheterization for PE in pregnant patients. This invasive procedure has an estimated morbidity and mortality of 3.5% to 6% and 0.2% to 0.5%, respectively [32,33]. If IV contrast is used, CTPA should be performed for diagnosis. The role of catheterization in intervention is not considered in this document.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. MRA Pulmonary Arteries Without and With IV Contrast In general, gadolinium-based contrast agents should be administered with caution to pregnant or potentially pregnant patients [66]. Because there are alternative methods to evaluate for PE in pregnancy that have greater benefit to the patient or fetus when compared with possible but unknown risk of fetal exposure to free gadolinium ions, MRA without and with IV contrast is rarely, if ever, performed.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. MRA Pulmonary Arteries Without IV Contrast Noncontrast MRA sequences alone for PE have been reported but remain investigational [43]. There is limited literature to support the use of noncontrast MRA of the pulmonary arteries for the evaluation of PE, including among pregnant patients [24,34].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. US Duplex Doppler Lower Extremity Compression US has an expanded role in pregnancy when compared with Variants 2 and 3 [45-49]. Pregnant patients with a positive compression US can be initiated on anticoagulation without further imaging. This strategy is particularly appealing for patients with symptoms of lower extremity DVT. Although there is a low false-negative rate of US [67], additional testing may be useful if an initial US does not show DVT.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. Suspected Pulmonary Embolism will undergo CTPA to identify a filling defect in the diagnosis of PE [51]. Risk stratification for right ventricular failure when there is a positive CTPA [52-57] is commonly used, but this clinical situation (after a diagnosis of PE) is not within the scope of this document.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. V/Q Scan Lung Unlike for patients who fall into Variants 2 and 3, V/Q scans are more frequently performed in pregnant patients [3,68,69]. Adjustments in the administered dose of the radiopharmaceutical(s) have been recommended [70,71], and if the perfusion scan is performed first and is normal, the ventilation scan may be avoided [72-74].


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. 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.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism

Suspected Pulmonary Embolism PCAs. Suspected Pulmonary Embolism


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism PCAs. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Suspected Pulmonary Embolism PCAs

Suspected Pulmonary Embolism


Acute Pyelonephritis

Acute Pyelonephritis. Introduction/Background Acute pyelonephritis (APN) is a severe urinary tract infection (UTI) that has the potential to cause sepsis, shock, and death [1]. The annual incidence of APN is 459,000 to 1,128,000 cases in the United States and 10.5 to 25.9 million cases globally [1,2]. The term pyelonephritis implies that there is inflammation of the renal pelvis and kidney. APN often presents with signs and symptoms of both systemic inflammation (eg, fever, chills, and fatigue) and bladder inflammation (eg, urgency, dysuria, and urinary frequency) [1]. There is a surprising lack of consensus regarding diagnostic criteria, and differentiation from infections of the lower urinary tract can be difficult [1]. Clinical presentation of APN can range from mild flank pain with low-grade or no fever to septic shock, and up to 20% of patients lack bladder symptoms. In patients with flank pain or tenderness, without or with voiding symptoms, without or with fever, and with a urinalysis showing pyuria and/or bacteriuria, APN is an appropriate presumptive diagnosis [1]. In this setting, urine cultures yielding >10,000 colony-forming units of a uropathogen per milliliter of urine is the fundamental confirmatory diagnostic test. Positive blood cultures may assist with the diagnosis.


Acute Pyelonephritis

Acute Pyelonephritis. In young healthy women, Escherichia coli accounts for more than 90% of APN cases [1,3]. However, in men, elderly women, and urologically compromised and institutionalized patients, less-virulent E. coli strains, gram- negative bacilli, gram-positive organisms, and candida are also common [1,4]. Risk factors for cystitis predispose to APN and include sexual activity, new sexual partner, spermicide exposure, personal or maternal history of UTIs, genetic predisposition, and diabetes mellitus [1,5]. Fortunately, <3% of cases of cystitis and asymptomatic bacteriuria progress to APN [1,6]. Factors that disrupt urinary flow such as vesicoureteral reflux, congenital urinary tract anomalies, altered bladder function, pregnancy, renal calculi, or mechanical obstruction increase the risk of developing APN [1,7,8].


Acute Pyelonephritis

Acute Pyelonephritis. In the majority of patients, uncomplicated APN is diagnosed clinically and is responsive to treatment with appropriate antibiotics [1]. In patients who are high risk or when treatment is delayed, microabscesses may coalesce to form an acute renal abscess. The renal parenchymal abscess can at times rupture into the perinephric space and lead to development of a perirenal abscess. In other cases, the infection may be confined to an obstructed collecting system causing pyonephrosis, or accumulation of purulent material in the upper urinary collecting system, that often requires decompression for treatment to be successful.


Acute Pyelonephritis

Acute Pyelonephritis. Some patients are at high risk for developing complications from APN. High-risk patients include those with a prior history of pyelonephritis, a lack of response to therapy for lower UTI or for APN, diabetes, anatomic or congenital abnormalities of the urinary system, infections by treatment-resistant organisms, nosocomial infection, urolithiasis, renal obstruction, prior renal surgery, advanced age, and pregnancy; renal transplant recipients; and immunosuppressed or immunocompromised patients [1,8-10]. Pregnant patients and patients with renal transplants on immunosuppression are at elevated risk of severe complications. Imaging studies are often requested to aid with the diagnosis, identify precipitating factors, and differentiate lower UTI from renal parenchymal involvement,


Acute Pyelonephritis

Acute Pyelonephritis. aUniversity of Alabama at Birmingham, Birmingham, Alabama. bPanel Chair, Northwestern University, Chicago, Illinois. cPanel Vice-Chair, UT Southwestern Medical Center, Dallas, Texas. dIndiana University, Indianapolis, Indiana; Committee on Emergency Radiology-GSER. eUT Southwestern Medical Center, Dallas, Texas. fThe University of Texas MD Anderson Cancer Center, Houston, Texas. gUniversity of Washington, Seattle, Washington; American Urological Association. hDuke University Medical Center, Durham, North Carolina. iSwedish Medical Center, Issaquah, Washington; American College of Emergency Physicians. jThomas Jefferson University Hospital, Philadelphia, Pennsylvania. kRoswell Park Cancer Institute, Jacobs School of Medicine and Biomedical Science, Buffalo, New York. lCleveland Clinic, Cleveland, Ohio. mMedical University of South Carolina, Charleston, South Carolina; American Urological Association. nNew York University Langone Medical Center, New York, New York. oRhode Island Hospital/The Warren Alpert Medical School of Brown University, Providence, Rhode Island; Commission on Nuclear Medicine and Molecular Imaging. pUniversity of Alabama at Birmingham Medical Center, Birmingham, Alabama, Primary care physician. qSpecialty Chair, University of Alabama at Birmingham, Birmingham, Alabama.


Acute Pyelonephritis

Acute Pyelonephritis. Reprint requests to: publications@acr.org


Acute Pyelonephritis

Acute Pyelonephritis. Special Imaging Considerations CT urography (CTU) is an imaging study that is tailored to improve visualization of both the upper and lower urinary tracts. There is variability in the specific parameters, but it usually involves unenhanced images followed by intravenous (IV) contrast-enhanced images, including nephrographic and excretory phases acquired at least 5 minutes after contrast injection. Alternatively, a split-bolus technique uses an initial loading dose of IV contrast and then obtains a combined nephrographic-excretory phase after a second IV contrast dose; some sites include the arterial phase. CTU should use thin-slice acquisition. Reconstruction methods commonly include maximum intensity projection or 3-D volume rendering. For the purposes of this document, we make a distinction between CTU and CT abdomen and pelvis without and with IV contrast. CT abdomen and pelvis without and with IV contrast is defined as any protocol not specifically tailored for evaluation of the upper and lower urinary tracts and without both the precontrast and excretory phases.


Acute Pyelonephritis

Acute Pyelonephritis. MR urography (MRU) is also tailored to improve imaging of the urinary system. Unenhanced MRU relies upon heavily T2-weighted imaging of the intrinsic high signal intensity from urine for the evaluation of the urinary tract. IV contrast is administered to provide additional information regarding obstruction, urothelial thickening, focal lesions, and stones. A contrast-enhanced T1-weighted series should include corticomedullary, nephrographic, and excretory phase. Thin-slice acquisition and multiplanar imaging should be obtained. For the purposes of this document, we make a distinction between MRU and MRI abdomen and pelvis without and with IV contrast. MRI abdomen and pelvis without and with IV contrast is defined as any protocol not specifically tailored for evaluation of the upper and lower urinary tracts, without both the precontrast and excretory phases, and without heavily T2- weighted images of the urinary tract.


Acute Pyelonephritis

Acute Pyelonephritis. OR Discussion of Procedures by Variant Variant 1: Suspected acute pyelonephritis. First-time presentation. Uncomplicated patient (eg, no history of pyelonephritis, diabetes, immune compromise, history of stones or renal obstruction, prior renal surgery, advanced age, vesicoureteral reflux, lack of response to therapy, or pregnancy). Initial imaging. CT Abdomen and Pelvis CT of the abdomen and pelvis is not beneficial in the initial imaging evaluation for the first-time presentation of suspected APN in an uncomplicated patient [1,10,14,15]. CT imaging may be useful if symptoms persist for 72 hours [8,10,14,16]. Nearly 95% of patients with uncomplicated pyelonephritis become afebrile within 48 hours after appropriate antibiotic therapy, and nearly 100% become afebrile within 72 hours [8,14].


Acute Pyelonephritis

Acute Pyelonephritis. CT Abdomen CT of the abdomen is not beneficial in the initial imaging evaluation for the first-time presentation of suspected APN in an uncomplicated patient [1,10,14,15].


Acute Pyelonephritis

Acute Pyelonephritis. CTU CTU is not beneficial in the initial imaging evaluation for the first-time presentation of suspected APN in an uncomplicated patient [1,10,14,15].


Acute Pyelonephritis

Acute Pyelonephritis

Acute Pyelonephritis. Acute Pyelonephritis


Acute Pyelonephritis

Acute Pyelonephritis. Fluoroscopy Antegrade Pyelography Antegrade pyelography is not beneficial in the initial imaging evaluation for the first-time presentation of suspected APN in an uncomplicated patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. Fluoroscopy Voiding Cystourethrography Fluoroscopy voiding cystourethrography (VCUG) is not beneficial in the initial imaging evaluation for the first- time presentation of suspected APN in an uncomplicated patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. MRI Abdomen and Pelvis MRI of the abdomen and pelvis is not beneficial in the initial imaging evaluation for the first-time presentation of suspected APN in an uncomplicated patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. MRI Abdomen MRI of the abdomen is not beneficial in the initial imaging evaluation for the first-time presentation of suspected APN in an uncomplicated patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. MRU MRU of the abdomen and pelvis is not beneficial in the initial imaging evaluation for the first-time presentation of suspected APN in an uncomplicated patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. Radiography Abdomen and Pelvis Radiography of the abdomen and pelvis (KUB) is not beneficial in the initial imaging evaluation for the first-time presentation of suspected APN in an uncomplicated patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. Radiography Intravenous Urography Intravenous urography (IVU) is not beneficial in the initial imaging evaluation for the first-time presentation of suspected APN in an uncomplicated patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. US Abdomen Ultrasound (US) of the abdomen is not beneficial in the initial imaging evaluation for the first-time presentation of suspected APN in an uncomplicated patient [15]. In addition, US had inferior accuracy for detection of APN compared with CT [10,17].


Acute Pyelonephritis

Acute Pyelonephritis. US Color Doppler Kidneys and Bladder Retroperitoneal US color doppler of the kidneys, bladder, and retroperitoneum is not beneficial in the initial imaging evaluation for the first-time presentation of suspected APN in an uncomplicated patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. Variant 2 : Suspected acute pyelonephritis. Complicated patient (eg, recurrent pyelonephritis, diabetes, immune compromise, adv anced ag e, vesicoureteral reflux, or lack of response to initial therapy). Initial imaging. The goal of imaging in a complicated patient with suspected APN is to identify the presence or absence of APN and identify associated complications. Patients with a history of renal calculi are separately discussed in variant 3. CT Abdomen and Pelvis There is widespread agreement that CT of the abdomen and pelvis with IV contrast is a useful study to diagnose APN in a complicated patient without a prior history of stone disease [1,8,14-21]. CT imaging should include the pelvis for multiple reasons. For example, unsuspected urolithiasis can be in the distal ureters or urinary bladder, congenital abnormalities of the distal ureters and abnormal insertion sites can be identified, and abnormalities of the urinary bladder can be detected, among other potential sources of APN.


Acute Pyelonephritis

Acute Pyelonephritis. Contrast-enhanced CT can be used to detect signs of APN including focal or multifocal decreased parenchymal enhancement, complications of APN including a renal or perirenal abscess or emphysematous pyelonephritis, and underlying problems including hydronephrosis, obstructing stones, or congenital abnormalities [1,8,14,17-19]. In a retrospective study of patients with suspected APN that underwent both unenhanced and contrast-enhanced CT (n = 183), contrast-enhanced CT detected parenchymal inv olvement in 62.5% of patients, whereas unenhanced CT detected parenchymal involvement in only 1.4% of cases, and 4.6% of patients had renal abscesses that were missed on unenhanced CT and on ly detected on contrast-e nhanced CT [19] . Furthermore, un enhanced CT missed the


Acute Pyelonephritis

Acute Pyelonephritis


Acute Pyelonephritis

Acute Pyelonephritis. diagnosis of acute extrarenal conditions including cholecystitis (n = 1), liver abscess (n = 1), and appendicitis (n =1), which were all subsequently diagnosed with contrast-enhanced CT [19].


Acute Pyelonephritis

Acute Pyelonephritis. In the absence of a history of renal stones, the benefit of performing unenhanced CT in combination with contrast- enhanced CT is negligible in a complicated patient with suspected APN. In a small retrospective study of adult patients with clinical and laboratory suspicion of APN who all underwent triphasic abdominal CT (n = 100), the accuracy of the nephrographic phase among 2 readers for diagnosis of APN was 90% to 92% and for diagnosis of urolithiasis was 96% to 99% [22]. There was no significant difference in the accuracy of the triphasic abdominal CT relative to the nephrographic phase only [22].


Acute Pyelonephritis

Acute Pyelonephritis. In a prospective nonrandomized data collection study of patients with a final diagnosis of APN (n = 827), the detection rate of APN was 84.4% (445/527) by abdominal CT and only 40% (72/180) by abdominal US [10]. Although the detection rate of urolithiasis and hydronephrosis were similar by abdominal CT and abdominal US, the rate of detection of renal abscess was 4.0% (21/527) by abdominal CT and only 1.1% (2/180) by US [10].


Acute Pyelonephritis

Acute Pyelonephritis. US, CT, and MRI can show evidence of chronic pyelonephritis, including renal scarring, atrophy and cortical thinning, hypertrophy of residual normal tissue, and renal asymmetry [1,8,14,15,17,19,20]. Advantages of abdominal CT and US over abdominal MRI may include superior detection of urolithiasis, and CT may be superior to US and MRI in detection of gas in emphysematous pyelonephritis [1,14,15,18].


Acute Pyelonephritis

Acute Pyelonephritis. Contrast-enhanced CT of the abdomen and pelvis is supported in high-risk or complicated patients if initial treatment is unresponsive or symptoms worsen [1,2,8,10,15,17-19]. In general, contrast-enhanced CT of the abdomen and pelvis should be delayed 72 hours after initiation of therapy [1,8,14-21].


Acute Pyelonephritis

Acute Pyelonephritis. CT Abdomen CT of the abdomen with IV contrast has high accuracy for the diagnosis of APN in a complicated patient but does not allow for a comprehensive assessment of the entire genitourinary tract [1,8,14-21]. CT imaging should include the pelvis to detect potential pelvic abnormalities including urolithiasis in the distal ureters or urinary bladder, congenital abnormalities of the distal ureters and abnormal insertion sites, and abnormalities of the urinary bladder, among other potential sources of APN.


Acute Pyelonephritis

Acute Pyelonephritis. CTU CTU There is insufficient evidence to support the use of CTU for detection of suspected APN in the complicated patient. There is variability in CTU imaging technique. The added benefit of an excretory phase from any CTU image acquisition protocol is likely negligible with respect to detection and characterization of APN in a complicated patient.


Acute Pyelonephritis

Acute Pyelonephritis. DMSA Renal Scan According to the literature, renal scintigraphy, specifically Tc-99m DMSA scan, is not beneficial for the diagnosis of APN in adults. In contrast, renal scintigraphy is useful in the pediatric population where there is difficulty in differentiating lower UTI from APN [23]. However, differentiation of lower UTI from APN is less problematic in adults, and pediatric vesicoureteral reflux often resolves in adulthood. Furthermore, in a small prospective study of adult patients with UTIs who underwent both contrast-enhanced CT and DMSA (n = 36), CT had higher accuracy in diagnosis of APN [24].


Acute Pyelonephritis

Acute Pyelonephritis. Fluoroscopy Antegrade Pyelography Antegrade pyelography is not beneficial in the imaging evaluation for suspected APN in a complicated adult patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. Fluoroscopy Voiding Cystourethrography VCUG is commonly used to identify vesicoureteral reflux but is not beneficial in the acute setting. VCUG is usually performed after resolution of acute symptoms to assess for an underlying anatomic or congenital cause, particularly in children with recurrent febrile UTIs [25]. Adult women with predisposing factors suspicious for vesicoureteral reflux may also benefit from VCUG [26]. However, VCUG is likely of limited benefit in the acute setting.


Acute Pyelonephritis

Acute Pyelonephritis. MRI Abdomen and Pelvis MRI of the abdomen without or with IV contrast may be useful for detecting and characterizing congenital anomalies of the kidneys, and imaging of the pelvis could improve detection of congenital abnormalities of the distal ureters and abnormalities of the urinary bladder. In general, MRI of the pelvis is usually not combined with MRI of the abdomen unless an MRU is being performed. Diffusion-weighted imaging (DWI) [20] and contrast-


Acute Pyelonephritis

Acute Pyelonephritis

Acute Pyelonephritis. Acute Pyelonephritis


Acute Pyelonephritis

Acute Pyelonephritis. enhanced MRI have similar benefits in detecting renal abnormalities [27]. Studies in adults have shown that DWI can be useful in the diagnosis of uncomplicated pyelonephritis [28-30]. APN, renal abscesses, and pyonephrosis have lower apparent diffusion coefficient (ADC) values than normal renal cortical parenchyma [28]. As such, DWI and ADC provide a viable alternative to contrast-enhanced MRI or CT [30].


Acute Pyelonephritis

Acute Pyelonephritis. Disadvantages of MRI includes relatively poor accuracy for detection of urolithiasis and relatively reduced ability to detect gas in emphysematous py elonephritis [31,32] . Similar to CT, MRI does not provide benefit early in uncomplicated cases [8,14].


Acute Pyelonephritis

Acute Pyelonephritis. MRI Abdomen MRI of the abdomen has high accuracy for the diagnosis of APN in a complicated patient but does not allow for a comprehensive assessment of the entire genitourinary tract. Failure to include the pelvis could lead to a missed opportunity to detect urolithiasis in the distal ureters or urinary bladder, congenital abnormalities of the distal ureters and abnormal ureteral insertion sites, and abnormalities of the urinary bladder, among other potential sources of APN.


Acute Pyelonephritis

Acute Pyelonephritis. MRU The excretory phase of MRU does not confer additional benefit with respect to detection and characterization of APN in a complicated patient. Studies comparing MRU with DMSA renal scintigraphy for the detection of pyelonephritis and renal scaring have shown that MRU without and with IV contrast is at least equivalent or superior to DMSA for this specific purpose [33-35]. No studies of MRU without IV contrast were identified in the literature.


Acute Pyelonephritis

Acute Pyelonephritis. Radiography Abdomen and Pelvis Radiography of the abdomen and pelvis (KUB) is not beneficial in the imaging evaluation for suspected APN in a complicated adult patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. Radiography Intravenous Urography IVU is not beneficial in the imaging evaluation for suspected APN in a complicated adult patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. US Abdomen Although US of the abdomen has similar accuracy to CT for detection of urolithiasis and hydronephrosis, the main disadvantages of US compared with CT are a lower rate of detection of APN and renal abscess, but it can be performed portably and without IV contrast [10,36-38]. Of note, the sensitivity for detection of acute complicated pyelonephritis and for detection of a renal abscess is higher with contrast-enhanced US relative to unenhanced US [37,38]. In one small retrospective study of adults with APN (n = 100), the accuracy of contrast-enhanced US for detection of APN approached that of contrast-enhanced CT [39].


Acute Pyelonephritis

Acute Pyelonephritis. US Color Doppler Kidneys and Bladder Retroperitoneal US including color Doppler has been shown to increase sensitivity for detection of APN beyond grayscale US [40]. US with power Doppler has been shown to have sensitivities and specificities that approach 90% in children with APN [41,42] and may have similar results in adults.


Acute Pyelonephritis

Acute Pyelonephritis. Although US has similar accuracy to CT for detection of urolithiasis and hydronephrosis, the main disadvantages of US compared with CT are a lower rate of detection of APN and renal abscess [10,36-38]. Of note, the sensitivity for detection of acute complicated pyelonep hritis and for detection of a renal abscess is higher with contrast- enhanced US relative to unenhanced US [37,38].


Acute Pyelonephritis

Acute Pyelonephritis. Variant 3: Suspected acute pyelonephritis. History of renal stones or renal obstruction. Initial imaging. CT Abdomen and Pelvis Renal stones or renal obstruction can be a source of APN [1,8,11,15,18,19]. CT of the abdomen and pelvis is highly sensitive for detection of stones and hydronephrosis [8,11]. Furthermore, CT is a useful imaging study to diagnose APN if symptoms persist or worsen after 72 hours have passed [1,8,14-21]. CT imaging should include the pelvis to identify stones in the distal ureters or urinary bladder, congenital abnormalities of the distal ureters, and abnormalities of the urinary bladder, among other potential sources of APN.


Acute Pyelonephritis

Acute Pyelonephritis. Both unenhanced and contrast-enhanced CT are able to detect urolithiasis, perinephric fluid, renal swelling, and hydronephrosis [1,8,14,17-19]. However, contrast-e nhanced CT has been shown to improve detection of APN parenchymal changes, a renal abscess, and extrarenal acute conditions that may clinical present as suspicious for APN [19]. Of note, unenhanced CT has higher sensitivity than contrast-enhanced CT for detection of small renal calculi.


Acute Pyelonephritis

Acute Pyelonephritis


Acute Pyelonephritis

Acute Pyelonephritis. In a prospective nonrandomized data collection study of patients with a final diagnosis of APN (n = 827), the detection rate of APN was 84.4% (445/527) by abdominal CT and only 40% (72/180) by abdominal US [10]. Although the detection rate of urolithiasis and hydronephrosis were similar by abdominal CT and abdominal US, the rate of detection of renal abscess was 4.0% (21/527) by abdominal CT and only 1.1% (2/180) by US [10].


Acute Pyelonephritis

Acute Pyelonephritis. CT and US have similar detection rates for renal stones and hydronephrosis. Advantages of abdominal CT and US over abdominal MRI may include superior detection of small urothelial stones [1,14,15,18].


Acute Pyelonephritis

Acute Pyelonephritis. In a small retrospective study of adult patients with clinical and laboratory suspicion of APN who all underwent triphasic abdominal CT (n = 100), the accuracy of the nephrographic phase among 2 readers for diagnosis of APN was 90% to 92% and for diagnosis of urolithiasis was 96% to 99% [22]. There was no significant difference in the accuracy of the triphasic abdominal CT relative to nephrographic phase alone [22]. Thereby, detection of urothelial stones is similar with unenhanced and contrast-enhanced CT.


Acute Pyelonephritis

Acute Pyelonephritis. CT Abdomen CT of the abdomen without IV contrast has high accuracy for detection or renal stones, and CT of the abdomen with IV contrast has high accuracy for the diagnosis of APN. However, CT of the abdomen alone does not allow for a comprehensive assessment of the entire genitourinary tract [1,8,14-21]. CT imaging should include the pelvis to detect potential pelvic abnormalities including urolithiasis in the distal ureters or urinary bladder, congenital abnormalities of the distal ureters and abnormal insertion sites, and abnormalities of the urinary bladder, among other potential sources of APN.


Acute Pyelonephritis

Acute Pyelonephritis. CTU CTU There is insufficient evidence to support the use of CTU for detection of suspected APN in the complicated patient. There is variability in the CTU imaging technique. The added benefit of an excretory phase from any CTU image acquisition protocol is likely negligible with respect to detection and characterization of APN in a complicated patient.


Acute Pyelonephritis

Acute Pyelonephritis. DMSA Renal Scan CT may have higher accuracy than DMSA renal scintigraphy for detection of APN and certainly has higher accuracy for detection of stones, which cannot be directly visualized by renal scintigraphy [24].


Acute Pyelonephritis

Acute Pyelonephritis. Fluoroscopy Antegrade Pyelography Antegrade pyelography is not beneficial in the imaging evaluation for suspected APN in a patient with a history of renal stones or renal obstruction [15].


Acute Pyelonephritis

Acute Pyelonephritis. Fluoroscopy Voiding Cystourethrography VCUG is not beneficial in the imaging evaluation for suspected APN in a patient with a history of renal stones or renal obstruction [15].


Acute Pyelonephritis

Acute Pyelonephritis. MRI Abdomen and Pelvis MRI of the abdomen and pelvis can be useful for detecting APN, scarring, congenital anomalies of the kidneys, renal abscesses, hydronephrosis, and pyonephrosis [28-30], and imaging of the pelvis could improve detection of stones in the distal ureters or urinary bladder, congenital abnormalities of the distal ureters, and abnormalities of the urinary bladder, among other potential sources of APN. However, MRI has poor accuracy for the detection of small urothelial calculi [31,32]. Other disadvantages of MRI includes its relatively reduced ability to detect gas in emphysematous pyelonephritis [31,32]. Similar to CT, MRI is not beneficial early in uncomplicated cases [8,14].


Acute Pyelonephritis

Acute Pyelonephritis. MRI Abdomen MRI of the abdomen has high accuracy for the diagnosis of APN in a complicated patient but does not allow for a comprehensive assessment of the entire genitourinary tract. Failure to include the pelvis could lead to a missed opportunity to detect urolithiasis in the distal ureters or urinary bladder, congenital abnormalities of the distal ureters and abnormal ureteral insertion sites, and abnormalities of the urinary bladder, among other potential sources of APN.


Acute Pyelonephritis

Acute Pyelonephritis. MRI has poor accuracy for the detection of small urothelial calculi. Another disadvantage of MRI includes its relatively reduced ability to detect gas in emphysematous pyelonephritis [31,32].


Acute Pyelonephritis

Acute Pyelonephritis. MRU The excretory phase of MRU does not confer additional benefit with respect to detection and characterization of APN in a complicated patient. Furthermore, MRU has poor accuracy for the detection of small urothelial calculi


Acute Pyelonephritis

Acute Pyelonephritis

Acute Pyelonephritis. Acute Pyelonephritis


Acute Pyelonephritis

Acute Pyelonephritis. [31,32]. In a small prospective study comparing CTU with MRU in adult patients referred from the emergency department for evaluation of renal colic or hematuria (n = 70), all cases of urinary stones were detected by CTU (100%) versus 79% of cases detected by MRU [43]. Another disadvantage of MRU includes its relatively reduced ability to detect gas in emphysematous pyelonephritis [31,32].


Acute Pyelonephritis

Acute Pyelonephritis. Radiography Abdomen and Pelvis Radiography of the abdomen and pelvis (KUB) has limited utility in the imaging evaluation for suspected APN in a patient with a history of renal stones or renal obstruction [15]. Although radiography of the abdomen and pelvis could detect large calculi, it cannot detect APN.


Acute Pyelonephritis

Acute Pyelonephritis. Radiography Intravenous Urography IVU is not beneficial in the imaging evaluation for suspected APN in a patient with a history of renal stones or renal obstruction [15].


Acute Pyelonephritis

Acute Pyelonephritis. US Abdomen US of the kidneys has nearly 100% sensitivity for detection of large stones (>5 mm) and hydronephrosis, although the accuracy for detection of small stones (<3 mm) is poor [44,45].


Acute Pyelonephritis

Acute Pyelonephritis. Some disadvantages of US compared with CT are a lower rate of detection of APN and renal abscess [10,36-38]. Of note, the sensitivity for detection of acute complicated pyelonephritis and for detection of a renal abscess is higher with contrast-enhanced US relative to unenhanced US [37,38]. In one small retrospective study of adults with APN (n = 100), the accuracy of contrast-enhanced US for detection o f APN approached that of contrast- enhanced CT [39].


Acute Pyelonephritis

Acute Pyelonephritis. US Color Doppler Kidneys and Bladder Retroperitoneal US of the kidneys has nearly 100% sensitivity for detection of large stones (>5 mm) and hydronephrosis, although the accuracy for detection of small stones (<3 mm) is poor [44,45]. Use of color Doppler has been shown to increase sensitivity for detection of APN in adults and children [40-42]. Inclusion of the bladder could identify other abnormalities contributing to APN. A disadvantage of US compared with CT is a lower rate of detection of APN and renal abscess [10,36-38].


Acute Pyelonephritis

Acute Pyelonephritis. Variant 4: Suspected acute pyelonephritis. Pregnant patient with no other complications (eg, no history of diabetes, immune compromise, history of stones or renal obstruction, prior renal surgery, vesicoureteral reflux, or lack of response to therapy). Initial imaging. CT Abdomen and Pelvis There is no current literature specific to the use of CT of the abdomen and pelvis in the evaluation of suspected APN in pregnant patients. CT imaging of the abdomen and pelvis is not supported as the initial imaging in pregnant patients. The main disadvantage of using CT of the abdomen and pelvis in a pregnant patient is the risk of ionizing radiation to the embryo or fetus and the mother, particularly for the pelvic portion of the examination [46].


Acute Pyelonephritis

Acute Pyelonephritis. CT Abdomen There is no current literature to support the use of CT of the abdomen in the evaluation of suspected APN in pregnant patients. CT imaging of the abdomen does not allow for detection of pelvic abnormalities including urolithiasis in the distal ureters or urinary bladder, congenital abnormalities of the distal ureters and abnormal insertion sites, and abnormalities of the urinary bladder, among other potential sources of APN.


Acute Pyelonephritis

Acute Pyelonephritis. CTU CTU There is no current literature to support the use of CTU in the evaluation of suspected APN in pregnant patients. There is variability in CTU imaging technique. The added benefit of an excretory phase from any CTU image acquisition protocol is likely negligible with respect to the detection and characterization of APN in a pregnant patient. A CTU protocol that does not include unenhanced imaging and that uses a split bolus to achieve a mixed nephrographic and excretory phase could mask the presence of urolithiasis.


Acute Pyelonephritis

Acute Pyelonephritis. DMSA Renal Scan DMSA renal scintigraphy is not beneficial in the imaging evaluation for suspected APN in a pregnant patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. Fluoroscopy Antegrade Pyelography Antegrade pyelography is not beneficial in the imaging evaluation for suspected APN in a pregnant patient [15].


Acute Pyelonephritis

Acute Pyelonephritis


Acute Pyelonephritis

Acute Pyelonephritis. Fluoroscopy Voiding Cystourethrography VCUG is not beneficial in the imaging evaluation for suspected APN in a pregnant patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. MRI Abdomen and Pelvis There is no current literature specific to the use of MRI of the abdomen and pelvis in the evaluation of suspected APN in pregnant patients. MRI of the abdomen and pelvis is generally safe in pregnant patients and may be useful in certain situations. MRI does do not expose the embryo, or fetus, or pregnant mother to ionizing radiation and can be useful for detecting APN, scarring, congenital anomalies of the kidneys, renal abscesses, hydronephrosis, and pyonephrosis [28-30]. Although there are no known adverse effects to human fetuses and no known cases of nephrogenic systemic fibrosis linked to the use of clinical doses of gadolinium-based contrast agents (GBCAs) in pregnant patients, GBCAs should only be used if the indication is considered critical and the potential benefits justify the potential unknown risk to the fetus [47].


Acute Pyelonephritis

Acute Pyelonephritis. MRI of the abdomen can be useful for detecting APN, scarring, congenital anomalies of the kidneys, renal abscesses, hydronephrosis, and pyonephrosis [28-30]. DWI [20] and contrast-enhanced MRI have similar benefits in detecting renal abnormalities [27] . Stud ies in adults have shown that DWI can be useful in the diagnosis of pyelonephritis [28-30]. APN, renal abscesses, and pyonephrosis have lower ADC values than normal renal cortical parenchyma [28]. Inclusion of the pelvis could improve detection of abnormalities of the lower urinary tract.


Acute Pyelonephritis

Acute Pyelonephritis. MRI may allow for a limited evaluation of the embryo or fetus. However, traditional MRI examinations do n ot provide a comprehensive assessment of the urinary collecting systems [8,31,32]. The main disadvantages of MRI are poor accuracy for the detection of small urothelial calculi and reduced accuracy for detection of emphysematous pyelonephritis, [31,32].


Acute Pyelonephritis

Acute Pyelonephritis. MRI Abdomen There is no current literature specific to the use of MRI of the abdomen in the evaluation of suspected APN in pregnant patients. MRI of the abdomen does not allow for detection of pelvic abnormalities including urolithiasis in the distal ureters or urinary bladder, congenital abnormalities of the distal ureters and abnormal insertion sites, and abnormalities of the urinary bladder, among other potential sources of APN. MRI of the abdomen is generally safe in pregnant patients and may be useful in certain situations [28-30]. Although there are no known adverse effects to human fetuses and no known cases of nephrogenic systemic fibrosis linked to the use of clinical doses of GBCAs in pregnant patients, GBCAs should only be used if the indication is considered critical and the potential benefits justify the potential unknown risk to the fetus [47].


Acute Pyelonephritis

Acute Pyelonephritis. MRI of the abdomen may allow for a limited evaluation of the embryo or fetus, although most fetuses would not be included in the field of view. The main disadvantages of MRI are poor accuracy for the detection of small urothelial calculi and reduced accuracy for detection of emphysematous pyelonephritis [31,32].


Acute Pyelonephritis

Acute Pyelonephritis. MRU There is no current literature specific to the use of MRU without IV contrast in the evaluation of suspected APN in pregnant patients. The excretory phase of MRU does not confer additional benefit with respect to detection and characterization of APN in a pregnant patient.


Acute Pyelonephritis

Acute Pyelonephritis. Radiography Abdomen and Pelvis Radiography of the abdomen and pelvis is not beneficial in the imaging evaluation for suspected APN in a pregnant patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. Radiography Intravenous Urography IVU is not beneficial in the imaging evaluation for suspected APN in a pregnant patient [15].


Acute Pyelonephritis

Acute Pyelonephritis. US Abdomen There is no current literature specific to the use of US of the abdomen in the evaluation of suspected APN in pregnant patients. Pregnancy increases the risk of complications from APN, although poor obstetrical outcomes are rare [48]. US of the abdomen may be used to detect complications of APN. US of the abdomen is safe in pregnancy and is rapid and portable and does not require the use of contrast material [8]. US is often used as a screening examination in pregnancy, is sensitive and specific test for diagnosing hydronephrosis, and does not expose the patient or fetus to ionizing radiation [49,50].


Acute Pyelonephritis

Acute Pyelonephritis

Acute Pyelonephritis. Acute Pyelonephritis


Acute Pyelonephritis

Acute Pyelonephritis. Physiologic hydronephrosis of pregnancy occurs in >80% of pregnant patients in the second and third trimester; therefore, hydronephrosis alone is not a reliable sign of APN in pregnant patients [51]. Furthermore, US has a low detection rate of APN and renal abscess [10,36-38].


Acute Pyelonephritis

Acute Pyelonephritis. US Color Doppler Kidneys and Bladder Retroperitoneal There is no current literature specific to the use of US color Doppler of the kidneys, bladder, and retroperitoneum in the evaluation of suspected APN in pregnant patients. US of the kidney, ureters, and bladder is safe in pregnancy, is rapid and portable, and does not require the use of contrast material [8]. US is often used as a screening examination in pregnancy, is sensitive and specific test for diagnosing hydronephrosis, and does not expose the patient or fetus to ionizing radiation [49,50]. Use of color Doppler has been shown to increase sensitivity for detection of APN compared to US with grayscale imaging [40-42].


Acute Pyelonephritis

Acute Pyelonephritis. Physiologic hydronephrosis of pregnancy occurs in >80% of pregnant patients in the second and third trimester; therefore, hydronephrosis alone is not a reliable sign of APN in pregnant patients [51]. Furthermore, US has a lower detection rate of APN and renal abscess than CT [10,36-38].


Acute Pyelonephritis

Acute Pyelonephritis. Variant 5: Suspected acute pyelonephritis. History of pelvic renal transplant with native kidneys in situ and no other complications (eg, no history of pyelonephritis, diabetes, history of stones or renal obstruction, prior renal surgery, advanced age, vesicoureteral reflux, lack of response to therapy, or pregnancy). Initial imaging. Some local practice patterns do not routinely give IV contrast agents to patients with renal transplants. For this variant, we assumed there are no contraindications to IV contrast agents.


Acute Pyelonephritis

Acute Pyelonephritis. CT Abdomen and Pelvis There is no current literature specific to the use of CT of the abdomen and pelvis in the evaluation of suspected APN in a patient with a pelvic renal transplant and native kidneys in situ. CT of the abdomen and pelvis would include imaging of the native and transplant kidneys, and CT with IV contrast is highly accurate for the diagnose APN in a complicated patient, particularly if symptoms persist or worsen after 72 hours have passed [1,8,14-21].


Acute Pyelonephritis

Acute Pyelonephritis. Both unenhanced and contrast-enhanced CT are able to detect urolithiasis, perinephric fluid, renal swelling, and hydronephrosis [1,8,14,17-19]. Contrast-enhanced CT has been shown to improve detection of APN parenchymal changes, a renal abscess, and extrarenal acute conditions that may clinically present as suspicious for APN. CT imaging of the pelvis can detect potential pelvic abnormalities including urolithiasis in the distal ureters or urinary bladder, congenital abnormalities of the distal ureters and abnormal insertion sites, and abnormalities of the urinary bladder, among other potential sources of APN. Of note, unenhanced CT has higher sensitivity than contrast- enhanced CT for detection of small renal calculi.


Acute Pyelonephritis

Acute Pyelonephritis. CT Abdomen There is no current literature to support the use of CT of the abdomen in the evaluation of suspected APN in a patient with a pelvic renal transplant and native kidneys in situ. APN of a renal allograft is more common than APN of the native kidneys, and renal transplant recipients are at high risk for complications from a variety of factors, including immunosuppression [52]. CT of the abdomen would not include complete imaging of the pelvic transplant kidney(s), which might miss important pathology in the transplant kidney [1,8,14-21].


Acute Pyelonephritis

Acute Pyelonephritis. CTU CTU There is limited information on the benefit of CTU for detection of suspected APN in a patient with a pelvic renal transplant and native kidneys in situ. The added benefit of an excretory phase from any CTU image acquisition protocol is likely negligible with respect to detection and characterization of APN in this patient cohort.


Acute Pyelonephritis

Acute Pyelonephritis. DMSA Renal Scan DMSA renal scintigraphy is not beneficial in the imaging evaluation for suspected APN in a patient with a pelvic renal transplant and native kidneys in situ [15].


Acute Pyelonephritis

Acute Pyelonephritis. Fluoroscopy Antegrade Pyelography Antegrade pyelography is not beneficial in the imaging evaluation for suspected APN in a patient with a pelvic renal transplant and native kidneys in situ [15].


Acute Pyelonephritis

Acute Pyelonephritis. Fluoroscopy Voiding Cystourethrography VCUG is not beneficial in the imaging evaluation for suspected APN in a patient with a pelvic renal transplant and native kidneys in situ [15].


Acute Pyelonephritis

Acute Pyelonephritis


Acute Pyelonephritis

Acute Pyelonephritis. MRI Abdomen and Pelvis There is limited literature on the use of MRI of the abdomen and pelvis in the evaluation of suspected APN in a patient with a pelvic renal transplant and native kidneys in situ. APN is rare in native kidneys. However, APN of a renal allograft is more common, and renal transplant recipients are at high risk for complications from a variety of factors, including immunosuppression [52].


Acute Pyelonephritis

Acute Pyelonephritis. In a p rospective study of renal transplant recipients with suspected APN (n = 5 6), contrast-enhanced MRI was positive in 66% (37/56) of patients [53] . In a small retrospective study of 24 kidney transplant recipients who underwent MRI without IV contrast and had clinical suspicion of APN, 9 2% (22/24) of patients had positive findings on MRI, specifically on DWI and ADC images [54].


Acute Pyelonephritis

Acute Pyelonephritis. Studies in ad ult patients without renal transplants hav e shown that DWI can be useful in the diagnosis of uncomplicated pyelonephritis [28-30]. APN, renal abscesses, and pyonephrosis have lower ADC values than normal renal cortical parenchyma [28]. As such, DWI and ADC provide a viable alternative to contrast-enhanced MRI or CT [30].


Acute Pyelonephritis

Acute Pyelonephritis. The main disadvantages of MRI of the abdomen and pelvis are poor accuracy for the detection of small urothelial calculi and reduced accuracy for detection of emphysematous pyelonephritis, [31,32].


Acute Pyelonephritis

Acute Pyelonephritis. MRI Abdomen There is limited literature on the use of MRI of the abdomen in the evaluation of suspected APN in a patient with a pelvic renal transplant and native kidneys in situ. APN is rare in native kidneys, and abdominal imaging would not include complete imaging of the pelvic transplant kidney(s), which would likely miss important pathology in the transplant kidney [1,8,14-21].


Acute Pyelonephritis

Acute Pyelonephritis. MRI Pelvis There is limited literature on the use of MRI of the pelvis in the evaluation of suspected APN in a patient with a pelvic renal transplant and native kidneys in situ. Pelvic MRI alone would not include evaluation of the native kidneys. MRI of the abdomen and pelvis would be more comprehensive for identification of the source of the APN.


Acute Pyelonephritis

Acute Pyelonephritis. MRU There is no current literature specific to the use of MRU in the evaluation of suspected APN in patients with a pelvic renal transplant and native kidneys in situ. The excretory phase of MRU does not confer additional benefit with respect to detection and characterization of APN in a pregnant patient.


Acute Pyelonephritis

Acute Pyelonephritis. Radiography Abdomen and Pelvis Radiography of the abdomen and pelvis is not beneficial in the imaging evaluation for suspected APN in a patient with a pelvic renal transplant and native kidneys in situ [15].


Acute Pyelonephritis

Acute Pyelonephritis. Radiography Intravenous Urography IVU is not beneficial in the imaging evaluation for suspected APN in a patient with a pelvic renal transplant and native kidneys in situ [15].


Acute Pyelonephritis

Acute Pyelonephritis. US Abdomen APN is rare in native kidneys. Because an US of the abdomen would not include complete imaging of the pelvic transplant kidney(s), the examination is not likely to diagnose APN [1,8,14-21].


Acute Pyelonephritis

Acute Pyelonephritis. US Color Doppler Kidneys and Bladder Retroperitoneal APN is most commonly an issue with the transplant kidney. Because US Doppler of the kidneys, bladder, and retroperitoneum does not include imaging of the pelvic transplant kidney(s), the examination is not likely to diagnose APN.


Acute Pyelonephritis

Acute Pyelonephritis. US Duplex Doppler Kidney Transplant Renal transplant US includes grayscale and color doppler imaging and is commonly used to assess transplant dysfunction. According to the American Institute of Ultrasound in Medicine, renal transplant US is the recommended imaging examination to evaluate for suspected APN of a renal transplant. Renal transplant US has high resolution and high sensitivity for detection of renal transplant hydronephrosis, calculi, vascular abnormalities, and a renal or perirenal abscess.


Acute Pyelonephritis

Acute Pyelonephritis. In a prospective study of renal transplant recipients with suspected APN (n = 56) using contrast-enhanced MRI served as the reference standard that was positive in 66% (37/56), the contrast-enhanced US was positive in 63%


Acute Pyelonephritis

Acute Pyelonephritis

Acute Pyelonephritis. Acute Pyelonephritis


Acute Pyelonephritis

Acute Pyelonephritis. (35/56) of patients, with a reported sensitivity of 95%, a specificity of 100%, and a diagnostic accuracy of 96% [53].


Acute Pyelonephritis

Acute Pyelonephritis. 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.


Acute Pyelonephritis

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


Acute Pyelonephritis

Acute Pyelonephritis


Blunt Chest Trauma Suspected Cardiac Injury. aUniversity of Michigan Health System, Ann Arbor, Michigan. bPanel Chair, Duke University Medical Center, Durham, North Carolina. cPanel Chair, University of Chicago, Chicago, Illinois. dPanel Vice-Chair, Massachusetts General Hospital, Boston, Massachusetts. ePanel Vice-Chair, University of Kansas Medical Center, Kansas City, Kansas. fUniversity of Louisville School of Medicine, Louisville, Kentucky. gStanford University Medical Center, Stanford, California; The Society of Thoracic Surgeons. hUniversity of Southern California, Los Angeles, California. iThe University of Chicago Medical Center, Chicago, Illinois; American College of Physicians. jKaiser Permanente, Los Angeles, California. kVancouver General Hospital, Vancouver, British Columbia, Canada. lUniversity of Washington, Seattle, Washington. mUniversity of California San Diego, San Diego, California. nHarvard Medical School, Boston, Massachusetts. oNaval Medical Center Portsmouth, Portsmouth, Virginia. pMassachusetts General Hospital, Boston, Massachusetts. qStritch School of Medicine Loyola University Chicago, Maywood, Illinois; Society for Cardiovascular Magnetic Resonance. rDuke University School of Medicine, Durham, North Carolina; The Society of Thoracic Surgeons. sUniversity of Virginia Health Center, Charlottesville, Virginia; Society of Cardiovascular Computed Tomography. tWisconsin Heart Hospital, Milwaukee, Wisconsin; Nuclear cardiology expert. uDenver Health MC/UPI, Denver, Colorado; American College of Emergency Physicians. vSpecialty Chair, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin. wSpecialty Chair, UT Southwestern Medical Center, Dallas, Texas.


Blunt Chest Trauma Suspected Cardiac Injury. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through society representation on expert panels. Participation by representatives from collaborating societies on the expert panel does not necessarily imply individual or society endorsement of the final document.


Blunt Chest Trauma Suspected Cardiac Injury. Reprint requests to: publications@acr.org


Blunt Chest Trauma Suspected Cardiac Injury. 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.


Blunt Chest Trauma Suspected Cardiac Injury. CTA can also be performed with or without ECG gating. The ECG gating is usually prospective and allows for better assessment of cardiac injuries as well as concomitant aortic injuries in patients with blunt chest trauma and concomitant cardiac injuries.


Blunt Chest Trauma Suspected Cardiac Injury. The role of focused assessment with sonography for trauma (FAST) (or extended-FAST or chest abdominal-FAST in evaluating chest injury) is primarily one of triage; a positive FAST and signs of hemodynamic instability may lead to immediate surgical intervention rather than CT [14,15]. Ultrasound (US) may be able to diagnose certain thoracic and abdominal injuries, but it is an insufficient test to fully exclude injuries to these areas because it has a relatively lower specificity compared with CT [16]. Hemodynamic instability and findings such as abnormal ECG and increased level of high-sensitivity troponin in hemodynamically stable patients should raise the suspicion of cardiac injuries, and these patients should undergo rapid cardiac assessment by echocardiography [7,10].


Blunt Chest Trauma Suspected Cardiac Injury. An initial FAST examination can detect pericardial effusion and wall motion abnormality. Hall et al [11] analyzed the cardiac component of the FAST examination in hypotensive (systolic blood pressure <90 mm Hg) and normotensive trauma patients. The authors concluded that performing echocardiography in hypotensive blunt trauma patients is effective in evaluating myocardial rupture with limited evaluation of the right ventricle, valvular injuries such as valvular or perivalvular regurgitation, hemopericardium, tamponade, pneumopericardium, and myocardial infarction. The authors have also stressed that a cardiac FAST examination may not be an effective use of resources for normotensive blunt trauma patients.


Blunt Chest Trauma Suspected Cardiac Injury. In general, hemodynamically stable patients should be either monitored or evaluated by cardiac imaging if the abnormal ECG findings persist or cardiac troponin levels are rising [7]. Patients with normal ECG and cardiac troponin levels are usually considered low probability for cardiac blunt trauma and therefore can be safely discharged [7,18,19].


Blunt Chest Trauma Suspected Cardiac Injury. CT chest has been accepted as an imaging modality of choice in patients with blunt chest trauma [20-23]. The superior spatial resolution combined with the ability of contrast enhancement to display the anatomic structures and 3-D reconstructions allows for accurate assessment of cardiovascular anatomy and the associated detection of pathology. Ideally, CT chest in patients with suspected cardiac injuries as part of the blunt trauma evaluation should be performed with intravenous (IV) contrast. However, in some instances, CT chest could be performed either without or with and without IV contrast, as described in the CT chest sections below.


Blunt Chest Trauma Suspected Cardiac Injury. CT Chest Without IV Contrast In patients with suspected cardiac injury, CT chest studies without IV contrast can easily identify hemothorax or hemopericardium from pleural and pericardial effusion by measuring the attenuation within the pleural or pericardial space. CT chest without IV contrast can also accurately detect sternal fractures by evaluating the sagittal and 3-D reconstructions. Even though a sternal fracture in the setting of trauma is considered a benign condition, myocardial contusion and myocardial concussion leading to malignant ventricular arrhythmias can be encountered with this finding only if there are ECG changes and cardiac troponin levels are rising. It is difficult to predict which patients with a sternal fracture will develop cardiac complications. In a cohort of 54 patients with a suspected sternal fracture by emergency physicians in a multicenter descriptive retrospective study, only 72% of the patients had ECG performed at baseline, 33% had follow-up ECG, and 30% had troponin I assessment; in this group, 6% of the patients were diagnosed with arrhythmias and myocardial contusion. The authors also showed that only 38 (70%) of the patients with suspected sternal fractures were confirmed by imaging [24]. This study shows the importance of diagnosing sternal fractures in conjunction with ECG monitoring and troponin assessment to evaluate cardiac


Blunt Chest Trauma Suspected Cardiac Injury. Blunt Chest Trauma-Suspected Cardiac Injury injury in the setting of blunt trauma. However, it is noteworthy that echocardiography is not recommended in isolated sternal fractures in the presence of a normal ECG and cardiac troponins to evaluate for myocardial contusion [25]. The use of CT chest without IV contrast is of paramount importance in patients with prior chest surgery or retained metal fragments for accurate diagnosis of cardiac trauma and concomitant vascular injuries.


Blunt Chest Trauma Suspected Cardiac Injury. CT Chest Without and With IV Contrast CT chest with and without IV contrast is the most effective routine imaging modality for detecting thoracic injuries caused by blunt trauma. It accurately detects hemorrhage within the chest followed by identification of concomitant cardiovascular injuries as a source of bleeding.


Blunt Chest Trauma Suspected Cardiac Injury. CT Heart Function and Morphology ECG-gated cardiac CT with IV contrast can be used in the trauma setting to evaluate the cardiac structure and can detect cardiac chamber rupture and pericardial rupture [35]. A case report has described various entities such as rupture of the right ventricle with contained contrast extravasation [36], left atrial appendage tear, rupture of the atria at the junction with pulmonary veins, and inferior vena cava. The existing literature focuses on clinical decision scores along with a chest radiograph, ECG, and troponin assessment [37] as a screening algorithm to triage patients in whom cardiac CT has the potential to guide life-saving interventions. Cardiac CT has been demonstrated to be highly accurate for the detection of cardiac structural abnormalities in the nontrauma setting.


Blunt Chest Trauma Suspected Cardiac Injury. A case report described the right ventricular pseudoaneurysm following an MVA diagnosed with cardiac CT and missed with echocardiography [36]. Another case report described contrast extravasation from the apical portion of the right ventricle into the pericardial space compatible with contained ventricular rupture in addition to multiple chest injuries detected at CT [38]. Other case reports have described the ability of contrast-enhanced CT chest to detect enhancement defects in the myocardium suggestive of myocardial infarction in the setting of trauma. These findings triggered further imaging and subsequent intervention [21] to treat coronary artery dissection following blunt trauma [39]. In addition, another case report described a patient with a hemothorax caused by a left atrial appendage rupture, pleuropericardial tear, and cardiac herniation through the pericardium [40]. Moreover, case reports have described the ability of CT chest with IV contrast to detect enhancement defect in the myocardium suggestive of myocardial infarction and ventricular septal defect in the setting of trauma that triggered further imaging and intervention [6,21,41].


Blunt Chest Trauma Suspected Cardiac Injury. CTA Chest Although this document excludes the discussion of vascular injuries, CTA chest without and with IV contrast is useful in a patient with blunt chest trauma and suspected cardiac injury. This is because CT chest can identify the extent of cardiac injury as well as other concomitant injuries in the chest and, most importantly, can be used for surgical planning.


Blunt Chest Trauma Suspected Cardiac Injury. Blunt Chest Trauma-Suspected Cardiac Injury CTA Coronary Arteries Coronary CTA evaluates for potential posttraumatic coronary arterial dissection or occlusion resulting in myocardial infarction. There are limited data on the coronary CTA in patients with suspected myocardial infarction in the trauma setting. A case report has described various entities such as intramural hematomas or atypical dissection of the coronary artery [42] and enhancement defects in the myocardium suggestive of myocardial infarction in the setting of trauma. These findings triggered further imaging and subsequent intervention [21] to treat coronary artery dissection following blunt trauma [39]. Several case reports have described the use of coronary angiography as a diagnostic and therapeutic modality [40,43-46] to not only detect coronary artery dissection and thrombosis in patients with ECG abnormalities, or increased serum troponin level, but also treat with angioplasty or coronary artery stent placement. More recently, high-sensitivity cardiac troponins have become the mainstays in an emergency evaluation [7].


Blunt Chest Trauma Suspected Cardiac Injury. FDG-PET/CT Heart Cardiac fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT may be used to assess myocardial function, perfusion, and viability in the trauma setting.[37,47]. There are no data regarding the use of FDG-PET/CT heart in the setting of blunt chest trauma and suspected cardiac injury.


Blunt Chest Trauma Suspected Cardiac Injury. MRI Heart Function and Morphology There are no data regarding the use of MRI heart in the setting of blunt chest trauma and suspected cardiac injury. A few case reports describe the use of cardiac MR (CMR) in detecting viable myocardium using late gadolinium enhancement because of myocardial infarction in trauma patients [41,46] and a case report describing a heart herniation [48]. CMR is also useful for detecting cardiac injuries, particularly right ventricular injury and pericardial injury, quantifying valvular regurgitation, and detecting typical or atypical aortic dissection in patients. In many instances, the CMR protocol may be shortened to address the clinical question; however, it is still a longer examination than a CT scan. However, CMR may be helpful in selected patients with suspected cardiac trauma and equivocal echo findings.


Blunt Chest Trauma Suspected Cardiac Injury. MRI Heart With Function and Inotropic Stress There is no relevant literature regarding the use of CMR with function and inotropic stress in a hemodynamically stable patient with blunt trauma to evaluate suspected cardiac injuries.


Blunt Chest Trauma Suspected Cardiac Injury. MRI Heart With Function and Vasodilator Stress Perfusion There is no relevant literature regarding the use of CMR with function and inotropic stress in a hemodynamically stable patient with blunt trauma to evaluate suspected cardiac injuries.


Blunt Chest Trauma Suspected Cardiac Injury. Radiography Chest In any trauma setting, chest radiography is the first imaging modality to identify indirect findings that infer cardiac or pericardial injuries. However, the role of chest radiography in blunt cardiac trauma is often limited in quality because of motion artifacts and overlying devices and garments. Longitudinal prospective studies examining the diagnostic yield of imaging in a blunt cardiac trauma have not been possible because identification of indirect findings that infer cardiac injury are rare and often missed and are mainly discussed in case reports. Chest radiography alone has limited ability to detect traumatic cardiac injuries.


Blunt Chest Trauma Suspected Cardiac Injury. SPECT/CT MPI Rest and Stress Single-photon emission computed tomography (SPECT) may be used to assess myocardial function, perfusion, and viability in the trauma setting. The literature for use of SPECT is contradictory. In a prospective study involving 125 patients that evaluated the use of T1-201 thallous chloride SPECT in blunt chest trauma [49], the authors found that 11 out of 75 patients who screened positive and 3 out of 48 patients who screened negative developed serious arrhythmias such as premature ventricular beats and atrial fibrillation. They concluded that SPECT is useful to evaluate myocardial contusion in patients with blunt chest trauma. A meta-analysis study showed that radionuclide results did not correlate with cardiac complications whereas ECG abnormalities and cardiac troponins did in patients with blunt chest trauma [37]. This could be explained by the fact that SPECT better detects left ventricular abnormalities than right ventricular abnormalities, which are more common in blunt cardiac trauma.


Blunt Chest Trauma Suspected Cardiac Injury. SPECT/CT MPI Rest Only There is no relevant literature regarding the use of SPECT/CT MPI rest only to evaluate suspected cardiac injuries.


Blunt Chest Trauma Suspected Cardiac Injury. Blunt Chest Trauma-Suspected Cardiac Injury US Echocardiography Transesophageal Transesophageal echocardiography (TEE) can be used in the trauma setting; however, it is often time limited because of the hemodynamic instability of the patients, need for sedation, and concern about esophageal injury. TEE is of value when the TTE findings are equivocal and aortic injury is suspected [50]. In a prospective study of 105 patients with severe blunt chest trauma, 20 patients underwent TEE because of suboptimal TTE findings, 9 of whom were diagnosed with a myocardial contusion and 5 with acute aortic injury [50]. TEE is also useful in evaluating right heart and tricuspid valve [51]. There is no evidence to support the use of TEE in the trauma setting for isolated cardiac injury.


Blunt Chest Trauma Suspected Cardiac Injury. Valvular injuries are also rare but have been reported in the literature. Aortic and mitral valves are the most commonly affected, followed by tricuspid and pulmonic valves, because the mural pressure is higher on the left side of the heart [54]. Valvular injuries can present as perivalvular leak, dehiscence because of papillary muscle or chordae tendineae rupture, tearing of valve leaflets, or papillary muscle contusion leading to necrosis. Aortic and pulmonic valves are vulnerable to injury during early diastole and atrioventricular valves are prone to injury during early systole when the intraventricular pressure is increased [7]. All valvular injuries present with signs and symptoms of regurgitation, therefore, it is prudent to perform echocardiography and assess the severity of regurgitation to guide further management with surgical repair in severe cases. Several case reports describe posttraumatic severe mitral regurgitation requiring surgical repair following MVAs [55-57].


Blunt Chest Trauma Suspected Cardiac Injury. A few case reports have described the use of echocardiography for diagnosing wall motion abnormality in the setting of myocardial infarction and coronary artery dissection after blunt chest trauma, especially when myocardial contusion mimics myocardial infarction with elevated cardiac troponins [42,58]. Prompt identification of wall motion abnormality in coronary artery distribution following blunt chest trauma is important for the identification and treatment of coronary artery dissection. Additionally, when a wall motion abnormality is present in the absence of elevated high-sensitivity cardiac troponins, a diagnosis of myocardial concussion can be made. Myocardial concussion does not cause myocardial anatomic injuries that lead to necrosis and elevated high-sensitivity cardiac troponins but instead stretches the cell membrane, leading to activation of ion channels through mechanical- electrical coupling that trigger ventricular arrhythmias [59]. In summary, TTE is the first-line imaging modality used in evaluation of blunt cardiac trauma in patients with abnormal ECG and elevated cardiac troponins.


Blunt Chest Trauma Suspected Cardiac Injury. US Echocardiography Transthoracic Stress There is no relevant literature regarding the use of TTE stress in suspected myocardial infarction in the trauma setting.


Blunt Chest Trauma Suspected Cardiac Injury. Variant 2: Suspected cardiac injury following blunt trauma, hemodynamically unstable patient. Hemodynamically unstable patients are defined as persistent hypotension (systolic blood pressure <90 mm Hg or mean blood pressure <65 mm Hg) despite fluid resuscitation [17]. Hemodynamically unstable patients with ECG changes and elevated cardiac troponins worrisome for cardiac trauma are usually managed with advanced cardiac life support followed by echocardiography evaluation [7]. On the contrary, hemodynamically unstable patients with normal ECG and cardiac troponins are usually admitted for monitoring and echocardiography is only indicated for unstable patients with rising troponin levels [7].


Blunt Chest Trauma Suspected Cardiac Injury. Blunt Chest Trauma-Suspected Cardiac Injury CT Chest CT chest plays a complementary role in defining the extent of blunt cardiac trauma and is typically reserved for surgical planning in patients with ongoing symptoms and unclear clinical etiology [7]. For this purpose, CT in a hemodynamically unstable patient with blunt trauma is useful despite the lack of relevant literature to support this statement.


Blunt Chest Trauma Suspected Cardiac Injury. CT Heart Function and Morphology CT heart in a hemodynamically unstable patient with blunt trauma and possible cardiac injury is useful in clinically indicated scenarios despite the lack of direct evidence.


Blunt Chest Trauma Suspected Cardiac Injury. CTA Chest The use of CTA chest is helpful in a hemodynamically unstable patient with blunt trauma and possible cardiac injury if clinically indicated to define the extent of blunt chest trauma and identify concomitant thoracic injuries; it is also helpful for surgical planning. However, there is no relevant literature to support the use of CTA chest in a hemodynamically unstable patient with blunt trauma and possible cardiac injury.


Blunt Chest Trauma Suspected Cardiac Injury. CTA Coronary Arteries The lack of evidence does not support the use of CTA coronary in a hemodynamically unstable patient with blunt trauma and possible cardiac injury, but it could be done if clinically indicated.


Blunt Chest Trauma Suspected Cardiac Injury. FDG-PET/CT Heart There is no relevant literature to support the use of FDG-PET/CT in a hemodynamically unstable patient with blunt trauma and possible cardiac injury.


Blunt Chest Trauma Suspected Cardiac Injury. MRI Heart Function and Morphology There is no relevant literature to support the use of CMR function and morphology in a hemodynamically unstable patient with blunt trauma and possible cardiac injury.


Blunt Chest Trauma Suspected Cardiac Injury. MRI Heart With Function and Inotropic Stress There is no relevant literature regarding the use of CMR stress in a hemodynamically unstable patient with blunt trauma and possible cardiac injury.


Blunt Chest Trauma Suspected Cardiac Injury. MRI Heart With Function and Vasodilator Stress Perfusion There is no relevant literature regarding the use of CMR stress in a hemodynamically unstable patient with blunt trauma and possible cardiac injury.


Blunt Chest Trauma Suspected Cardiac Injury. Radiography Chest Bedside anteroposterior (AP) chest radiographs are commonly used as a first-line imaging modality in the evaluation of blunt thoracic trauma at most level I trauma centers in the United States, especially in hemodynamically unstable patients [26,60]. AP chest radiographs have limited ability to identify the direct findings of blunt cardiac injuries such as cardiac rupture, coronary artery dissection, pericardial tear, and valvular injuries. However, radiographs have the potential to identify indirect findings that infer cardiac or pericardial injuries. These indirect findings include hemothorax, widened mediastinum, enlarged cardiomediastinal silhouette, abnormal cardiac silhouette contour, changing cardiac position after tube thoracotomy, pneumopericardium, and displaced rib fractures, especially between the third and ninth ribs. These findings coupled with the appropriate clinical presentation should trigger a further evaluation of potential life-threatening cardiac and pericardial injuries [61-63]. Attention should be paid in patients with cardiac implantable electronic devices for possible device header fracture, lead fracture, or lead migration [64]. A case report of chest trauma that resulted in device malfunction showed an abnormal angulation between the device header and the body of the generator on a lateral chest radiograph [65].


Blunt Chest Trauma Suspected Cardiac Injury. Although an AP chest radiograph is the first-line imaging in trauma patients, it is often limited in quality because of motion artifacts and overlying devices and garments. The evaluation of the mediastinum is also limited with only an AP projection image. Several studies have evaluated the diagnostic yield of the chest radiograph in the assessment of blunt thoracic injuries and have shown the value of using chest radiographs, especially when coupled with abdominal CT, chest CT, or a clinical decision score [23,66-73]. AP chest radiograph has a lower diagnostic yield for occult blunt traumatic injuries than chest CT, missing 80% of cases of hemothorax and 50% of vertebral and rib fractures compared with CT [68,69,72,73]. Hemothorax or hemopericardium can result from cardiac rupture and pericardial tamponade; sternal fracture can result in cardiac contusion or even rupture. Overall, chest radiography alone has limited ability to detect traumatic cardiac injuries.


Blunt Chest Trauma Suspected Cardiac Injury. Blunt Chest Trauma-Suspected Cardiac Injury SPECT/CT MPI Rest and Stress There is no relevant literature regarding the use of Tc-99m SPECT/CT MPI rest and stress in a hemodynamically unstable patient with blunt trauma and possible cardiac injury.


Blunt Chest Trauma Suspected Cardiac Injury. SPECT/CT MPI Rest Only There is no relevant literature regarding the use of Tc-99m SPECT/CT MPI rest only in a hemodynamically unstable patient with blunt trauma and possible cardiac injury.


Blunt Chest Trauma Suspected Cardiac Injury. US Echocardiography Transesophageal TEE is more sensitive than TTE and is often recommended when TTE is not diagnostic and the suspicion of cardiac causes remains high. Even though there is no relevant literature regarding the use of TEE rest in a hemodynamically unstable patient with blunt trauma and possible cardiac injury, TEE rest is useful if clinically indicated.


Blunt Chest Trauma Suspected Cardiac Injury. US Echocardiography Transthoracic Resting TTE resting is a first-line imaging modality in the evaluation of suspected cardiac trauma in the setting of blunt chest trauma. TTE can easily assess the biventricular systolic function, pericardial effusion with suspected tamponade, myocardial rupture, wall motion abnormality, septal injuries, and valvular injuries in the setting of blunt chest trauma. The diagnostic yield of TTE is greater in patients who present with chest pain, abnormal ECG findings, rising troponin values, new arrhythmia, or clinical heart failure. Hemodynamically unstable patients with normal ECG and cardiac troponins should be monitored and TTE should be performed if the cardiac troponins are rising or if there is a new onset of arrhythmia or abnormal ECG changes.


Blunt Chest Trauma Suspected Cardiac Injury. US Echocardiography Transthoracic Stress There is no relevant literature regarding the use of TTE stress in a hemodynamically unstable patient with blunt trauma and possible cardiac injury.


Blunt Chest Trauma Suspected Cardiac Injury. 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.


Blunt Chest Trauma Suspected Cardiac Injury. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Blunt Chest Trauma Suspected Cardiac Injury. Blunt Chest Trauma-Suspected Cardiac Injury


Altered Mental Status Coma Delirium and Psychosis. Introduction/Background Altered mental status (AMS) and coma are terms used to describe disorders of arousal and content of consciousness. AMS may account for up to 4% to 10% of chief complaints in the emergency department (ED) setting and is a common accompanying symptom for other presentations [1,2]. AMS is not a diagnosis but rather a term for symptoms of acute or chronic disordered mentation [1], including confusion, disorientation, lethargy, drowsiness, somnolence, unresponsiveness, agitation, altered behavior, inattention, hallucinations, delusions, and psychosis [3,4]. Some of the most common disorders associated with AMS are underlying medical conditions, substance use, and mental disorders [5]. Validated assessment scales, such as the Richmond Agitation Sedation Scale and Glasgow Coma Scale, may be employed to objectively quantify the severity of symptoms [3,4]. The cause of AMS in patients across all age groups remains undiagnosed in slightly >5% of cases. Overall mortality in patients with AMS is approximately 8.1% and is significantly higher in elderly patients [4].


Altered Mental Status Coma Delirium and Psychosis. Two studies found that older patients presenting to the ED with the nonspecific chief complaint of AMS are likely to have delirium [6]. Delirium is a defined and diagnosable medical condition under Diagnostic and Statistical Manual of Mental Disorders, Fifth edition, which includes inattention as a cardinal feature, may fluctuate over the course of day with lucid intervals, and may present with subtle disturbances in consciousness compared with other forms of acute AMS, making detection more difficult and thus easy to miss [3,6]. Delirium is considered a medical emergency. Early detection and accurate diagnosis are extremely important because mortality in patients may be twice as high if the diagnosis of delirium is missed [7]. Up to 10% to 31% of patients may have delirium at admission, and it may develop in up to 56% of admitted patients [8], particularly following surgery or in the intensive care unit [8]. Delirium is commonly precipitated by 1 or more underlying cause, including another medical condition, intoxication, or withdrawal [9]. Management is based on treatment of the underlying cause, control of symptoms with nonpharmacological approaches, medication when deemed appropriate, and effective aftercare planning [3,6,10]. The economic impact of delirium in the United States is profound, with total costs estimated at $38 to $152 billion each year [11].


Altered Mental Status Coma Delirium and Psychosis. New onset psychosis is often listed as a separate subgroup under the AMS category. Delusions and hallucinations are 2 cardinal features of psychotic symptomatology. Additional symptoms may include disorganized speech or thought, disorganized or abnormal motor behavior including catatonia or agitation, and negative symptoms such as diminished expression of emotions [9]. In contrast with other presentations of AMS, awareness and level of consciousness in patients with psychosis are frequently intact [12]. If the psychotic symptoms are related to an underlying psychiatric disorder, such as schizophrenia, bipolar disorder, schizoaffective disorder, or depression with psychotic features, it is termed primary psychosis. Secondary causes of psychosis are thought to be directly related to drug/alcohol use, withdrawal, or an underlying medical cause [1,2] and are not better explained by delirium [9]. Medical conditions that may present with psychotic symptoms include endocrine disorders, autoimmune diseases, neoplasms and paraneoplastic processes, neurologic disorders, infections, genetic or


Altered Mental Status Coma Delirium and Psychosis. aStanford University School of Medicine, Stanford, California. bPanel Chair, Uniformed Services University, Bethesda, Maryland. cPanel Vice-Chair, Columbia University Medical Center, New York, New York. dClinica Family Health, Lafayette, Colorado; American Academy of Family Physicians. eUniversity of Virginia Health System, Charlottesville, Virginia. fUniversity of Michigan, Ann Arbor, Michigan; Commission on Nuclear Medicine and Molecular Imaging. gMontefiore Medical Center, Bronx, New York. hSan Antonio Military Medical Center, San Antonio, Texas; American Academy of Neurology. iUniversity of Washington, Seattle, Washington and University of British Columbia, Vancouver, British Columbia, Canada. jInova Fairfax Hospital, Falls Church, Virginia; American Psychiatric Association. kWeill Cornell Medical College, New York, New York. lThe University of Tennessee Health Science Center, Memphis, Tennessee; Society of General Internal Medicine. mUniversity of Chicago, Chicago, Illinois. nBrigham & Women's Hospital, Boston, Massachusetts; Committee on Emergency Radiology-GSER. oCedars-Sinai, Los Angeles, California; American Geriatrics Society. pNaval Medical Center Portsmouth, Portsmouth, Virginia. qUniversity of Colorado School of Medicine, Aurora, Colorado. rUniversity of Cincinnati Medical Center, Cincinnati, Ohio. sSpecialty Chair, University of Iowa Hospitals and Clinics, Iowa City, Iowa.


Altered Mental Status Coma Delirium and Psychosis. 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.


Altered Mental Status Coma Delirium and Psychosis. Reprint requests to: publications@acr.org


Altered Mental Status Coma Delirium and Psychosis. Altered Mental Status, Coma, Delirium, and Psychosis metabolic disorders, nutritional deficiencies, and drug-related intoxication, withdrawal, side effects, and toxicity. For secondary causes of psychosis, treatment is aimed at the underlying medical cause and control of the psychotic symptoms [12]. Treatment of primary causes of psychosis involves pharmacologic management with antipsychotic medications, psychological therapy, and psychosocial interventions [13].


Altered Mental Status Coma Delirium and Psychosis. This article focuses on the appropriateness of neuroimaging in adult patients presenting with AMS changes including new onset delirium or new onset psychosis. In these cases, imaging is often expedited for initial stabilization and to exclude an intracranial process requiring intervention. The diagnosis of delirium in the ED setting can be missed by inadequate screening [3,14], although ED physicians are moderately accurate at establishing the correct clinical diagnosis for the cause of AMS within the first 20 minutes of the patient encounter [15]. The complete evaluation for underlying causes, such as chest radiography to assess for pneumonia, electrocardiogram to assess for myocardial ischemia, electroencephalography for suspected convulsive or nonconvulsive seizure, and lumbar puncture to assess for central nervous system infection, is beyond the scope of this article [3,7].


Altered Mental Status Coma Delirium and Psychosis. OR Discussion of Procedures by Variant Variant 1: Adult. Altered mental status. Suspected intracranial pathology or focal neurologic deficit. Initial imaging. Identifying patients with AMS or delirium secondary to acute intracranial pathology is extremely important to guide management and ensure early appropriate triage. This variant encompasses a select group of patients presenting with acute mental status changes at a relatively higher risk of acute intracranial pathology.


Altered Mental Status Coma Delirium and Psychosis. The yield of neuroimaging studies in patients with AMS is low. A recent meta-analysis of 25 studies including a total of 79,201 patients with atraumatic AMS showed that 94% had undergone a head CT examination, with relevant abnormal findings in only 11% [24]. In a large study of more than 708,145 adult ED encounters, 58,783 CT head


Altered Mental Status Coma Delirium and Psychosis. Altered Mental Status, Coma, Delirium, and Psychosis