Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. WBC Scan Area of Interest A WBC scan has been reported to have variable sensitivity and specificity when performed alone in the evaluation of osteomyelitis [17]. The addition of SPECT/CT has been suggested to increase the accuracy of WBC scan for the diagnosis of osteomyelitis. When a WBC scan is positive on planar images, SPECT/CT can be performed for more accurate localization of infection [15,21].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Variant 4: Suspected osteomyelitis or soft tissue infection with implanted extra-articular surgical hardware. Initial radiographs normal or with findings suggestive of osteomyelitis or soft tissue infection with implanted extra-articular surgical hardware. Next imaging study. For osteomyelitis and soft tissue infection, the body regions covered are ankle, elbow, hip, knee, shoulder, wrist.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. 3-Phase Bone Scan and WBC Scan and Sulfur Colloid Scan Area of Interest There is insufficient evidence to support the use of 3-phase bone scan, WBC scan, and sulfur colloid scan for the evaluation of infection of extra-articular surgical hardware in the absence of known fluid collection or abscess.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. 3-Phase Bone Scan and WBC Scan Area of Interest A 3-phase bone scan has low specificity for infection in the setting of trauma or recent surgery. A WBC scan should be considered in patients with a low suspicion of infection who have positive findings on 3-phase bone scan [21].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. 3-Phase Bone Scan Area of Interest A meta-analysis by Wang et al [17] found that a 3-phase bone scan had sensitivity of 83% but specificity of <50%. In the setting of prior surgery or trauma, the specificity of 3-phase bone scan is likely even lower because osseous remodeling will result in radiotracer uptake [21]. Although studies have shown that SPECT/CT aids in anatomic localization of infection, findings often remain equivocal [19].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Suspected Osteomyelitis, Septic Arthritis


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. There is insufficient evidence to support the use of image-guided aspiration for evaluation of infection of extra- articular surgical hardware in the absence of known fluid collection or abscess.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. CT Area of Interest CT is useful in the evaluation of postsurgical complications including hardware fracture, periprosthetic osteolysis, and fracture nonunion [29]. Osseous changes of osteomyelitis can be visualized with CT, although these findings are often nonspecific, particularly if there has been recent trauma or surgery. CT can be helpful in identifying fluid collections adjacent to bone or surgical hardware that can be targeted for further investigation with percutaneous or surgical drainage. CT may also be useful in the detection of necrotic osseous fragments or sequestra that supply a nidus for chronic infection [21]. IV contrast should be considered because this may allow for better definition of fluid collections or fistulous communication to orthopedic implants [22].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. FDG-PET/CT Area of Interest A systematic review by Govaert et al [21] found that FDG-PET/CT has specificity for posttraumatic osteomyelitis ranging from 76% to 100% and sensitivity ranging from 83% to 100%. However, in the acute setting, inflammation due to fracture or recent surgery may decrease accuracy. A retrospective review by Hartmann et al [30] demonstrated sensitivity of 100% and specificity ranging from 88% to 93%. This study included patients with orthopedic implants and joint replacements. This small study of 33 patients also suggested that FDG-PET was most specific when evaluating infection in the axial skeleton. Wenter et al [22] retrospectively reviewed PET imaging performed in 215 patients for suspected osteomyelitis or implant associated infection and reported sensitivity of 88% and specificity of 76%. Their results also showed no significant decrease in accuracy in patients with orthopedic implants.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. MRI Area of Interest MRI is useful for the evaluation of osteomyelitis or soft tissue infection in the setting of extra-articular surgical hardware. MRI allows for characterization of both bone marrow signal and adjacent soft tissues. Recent advances in metal artifact reduction techniques have improved orthopedic hardware imaging, particularly in the appendicular skeleton [31]. In the setting of posttraumatic osteomyelitis, MRI can be used to determine the degree of osseous and soft tissue involvement. However, caution must be used in the recent postoperative or posttrauma period because bone marrow and soft tissue edema may persist and mimic infection [21]. IV contrast administration is preferred to help evaluate the soft tissues [27,32].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. US Area of Interest US may be used in detection of soft tissue abnormalities such as abscess or fistulous tracts. However, assessment of the underlying bone is typically limited with US findings of osteomyelitis either not visualized or nonspecific [28,33].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. WBC Scan and Sulfur Colloid Scan Area of Interest Combining a sulfur colloid scan with a WBC scan may reduce false positive results from normal WBC accumulation in bone marrow adjacent to orthopedic hardware. No studies were found that specifically investigated accuracy of combined WBC scan and sulfur colloid scan in diagnosing osteomyelitis associated with extra-articular hardware. Because sulfur colloid is a bone marrow imaging technique, there is no added benefit for assessment of soft tissue infection associated with orthopedic hardware. The addition of SPECT/CT hybrid imaging may increase ability to localize infection in cases with orthopedic hardware.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. WBC Scan Area of Interest A systematic review by Govaert et al [21] found that a WBC scan for posttraumatic osteomyelitis had sensitivity ranging from 50% to 100% and specificity ranging from 40% to 97%. The addition of SPECT/CT hybrid imaging may increase ability to localize infection in cases with orthopedic hardware.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Variant 5: Suspected septic arthritis with arthroplasty or other implanted intra-articular surgical hardware. Initial radiographs normal or with findings suggestive of septic arthritis with arthroplasty or other implanted intra-articular surgical hardware. Next imaging study. For septic arthritis, the body regions covered are ankle, elbow, hip, knee, shoulder, wrist.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. 3-Phase Bone Scan and WBC Scan and Sulfur Colloid Scan Area of Interest There is insufficient evidence to support the use of 3-phase bone scan, WBC scan, and sulfur colloid scan for evaluation of suspected septic arthritis.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. 3-Phase Bone Scan and WBC Scan Area of Interest While the literature does not support routine use of 3-phase bone scan and WBC scan for suspected periprosthetic infection, WBC may be performed following a positive bone scan to assess for infection. A 3-phase bone scan can be positive for multiple reasons in the post arthroplasty setting. Trevail et al [34] suggested the addition of WBC scan following a positive arthroplasty is up to 99% specific for infection and 80% sensitive.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. 3-Phase Bone Scan Area of Interest Bone scintigraphy alone has high sensitivity and low specificity in the evaluation of suspected periprosthetic joint infection [35,36]. A negative 3-phase bone scan suggests low probability of periprosthetic infection [34,37].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Image-Guided Aspiration Area of Interest The use of image-guided joint aspiration is supported to evaluate suspected septic arthritis. Depending on the joint, image guidance may be used to access the joint and confirm intra-articular needle positioning in the event of dry tap. Joint aspiration may be performed under fluoroscopy, US, or, less commonly, CT. The decision of imaging modality should be based on operator expertise and comfort because no modality has been proven superior to others. Laboratory analysis should include cultures, Gram stain, and cell count with differential [31,38,39].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. CT Area of Interest CT can be used to evaluate hardware complications including osteolysis adjacent to implanted hardware. The use of metal artifact reduction techniques can improve the detection of joint effusion, soft tissue abscess, and periostitis. CT is also helpful in identifying necrotic bone fragments or sequestra in the setting of chronic osteomyelitis [21,31]. Although IV contrast is not helpful for assessment of osteomyelitis, the addition of IV contrast may aid in the detection of synovial thickening or soft tissue abscesses [11].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. FDG-PET/CT Area of Interest A meta-analysis by Verberne et al [36] showed that there was considerable heterogeneity in the literature regarding the diagnostic criteria for prosthetic joint infection. The authors suggested that radiotracer accumulation around prosthetic head, neck, and distal tip may persist for up to 2 years following implantation, thus limiting evaluation of septic arthritis. Although there seems to be promise for FDG-PET/CT in the evaluation of prosthetic joint infection, the specificity of PET/CT in the diagnosis of septic arthritis remains uncertain because of a lack of clearly defined diagnostic criteria [40].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. MRI Area of Interest Although MRI is susceptible to metallic artifact as a result of indwelling hardware, metal reduction sequences have mitigated this as a limitation. MRI is useful at detection of osseous changes of osteomyelitis with high sensitivity and specificity. MRI findings of synovial enhancement, joint effusion, and T1 hypointense bone marrow signal changes have a high correlation with infection [41]. MRI also provides evaluation of adjacent soft tissues including tendons and muscles that may offer an alternative diagnosis to infection in patients with pain following arthroplasty [42]. MRI is accurate for localization of soft tissue fluid collections that may be targeted for aspiration or surgical drainage. One disadvantage of MRI is that bone marrow signal abnormalities may persist for months following injury or surgery. [21]. IV contrast administration should be considered because this can assist in differentiating abscess from phlegmon [32,43].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. US Area of Interest US may be useful for the detection of synovial thickening or joint effusion. However these are not specific to septic arthritis. US limitations include difficulty imaging deeper structures, deep larger joints (such as the shoulder or hip), an inability to evaluate metal implants, and a lack of sensitivity and specificity to findings such as fistulous tracts, subperiosteal fluid collections, and periosteal thickening [28,33].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. WBC Scan and Sulfur Colloid Scan Area of Interest The addition of a sulfur colloid scan is useful in cases in which results are equivocal for septic loosening or osteomyelitis because leukocytes may accumulate in marrow adjacent to orthopedic implants [36,44]. However, the addition of a sulfur colloid bone marrow scan to a WBC scan does not increase the accuracy for detection of septic arthritis. The addition of SPECT/CT is recommended in positive studies to aid in the differentiation of soft tissue infection from osteomyelitis.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. WBC Scan Area of Interest Systematic reviews by Verberne et al [36] and Van der Bruggen et al [45] both describe significant variability in specificity and sensitivity of WBC scan ability to diagnosis infection of orthopedic implants. This is likely due to


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Suspected Osteomyelitis, Septic Arthritis variability in scanning technique and criteria used for diagnosis of prosthetic related infection. In a study of 215 patients, Trevail et al [34] reported that a WBC scan had a sensitivity of 80% and a specificity >99%. The addition of SPECT/CT is recommended in positive studies to aid in the differentiation of soft tissue infection from osteomyelitis.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Variant 6: Suspected soft tissue infection. History of puncture wound with possible retained foreign body. Radiographs normal. Next imaging study. For soft tissue infection, the body regions covered are abdomen, neck, ankle, chest, elbow, thigh, foot, forearm, hand, hip, arm, knee, pelvis, shoulder, leg, wrist.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. In patients with puncture wounds, one of the main goals of imaging is to determine the presence or absence of a retained foreign body. Around the foreign body and puncture wound, soft tissue granulomatous reaction occurs and a superimposed soft tissue infection can develop including cellulitis, abscess, myositis, septic arthritis, or sinus tract.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Foreign bodies are either radiodense or radiolucent. Metal, stone, and graphite are radiodense and are detected on radiographs. However, plastic, rubber, and wood are not visible or radiolucent. Glass and ceramic are not always seen on radiographs.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. CT can evaluate for the complications of foreign body infections such as cellulitis, muscle/fascial edema, abscesses, sinus tracts, and vascular or tendon injuries. Vascular injuries or pseudoaneurysms are best evaluated with the administration of IV contrast. However, soft tissue changes associated with foreign bodies, such as peripheral edema, hyperemia, and inflammation, may require a more sensitive modality such as MRI or US. CT can detect bone changes related to foreign bodies including osseous destruction, sclerosis, periosteal reaction, or intraosseous abscess [46,47]. Although CT can detect foreign bodies embedded in bone, CT is not as sensitive as MRI for detecting bone marrow edema.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. MRI Area of Interest On MRI, foreign bodies are usually low signal on all sequences and demonstrate morphology that is not anatomic (ie, linear or polygonal shape). MRI is the most sensitive modality for evaluating the soft tissue and osseous changes of infection; however, it is not sensitive or specific for detecting foreign bodies. Especially if the foreign bodies are small, many may be missed. Because of the granulomatous, inflammatory response to foreign bodies within soft tissues, surrounding fluid signal, edema, peripheral enhancement is a dominant pattern on MRI, which can be used to help localize foreign bodies. MRI with IV contrast can also assess complications of foreign bodies in soft tissues and bone, including cellulitis, fasciitis, abscesses, sinus tracts, osteomyelitis, and vascular or tendon injuries. Compared with US and CT, MRI has a lower sensitivity and inferior spatial resolution for detection of foreign bodies. Radiodense foreign bodies are better visualized on radiography [46].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Metallic foreign bodies and air produce susceptibility artifact, which can limit MRI quality. With metallic objects and MRI, there is a potential for severe soft tissue heating and motion of the foreign body because of the magnetic field. The severity of this risk is dependent on the ferromagnetic properties and location of the metallic foreign body, how long the foreign body has been in place, and the strength of the MRI unit [47]. Therefore, radiographic screening for metallic foreign bodies is recommended before MRI.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. US Area of Interest If a foreign body is not visualized on radiographs, US can be used for further evaluation especially in the acute, emergency setting [46,47]. US has a reported sensitivity of 95% for the detection of foreign bodies [48]. Tantray et al [48] reported out of 120 patients that went to surgery for foreign body exploration, US visualized foreign bodies in 114 patients. Among the 6 patients with negative US, only 1 patient had a foreign body on surgery. In addition, US can further characterize foreign body morphology, depth, and location in relation to adjacent structures like


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Suspected Osteomyelitis, Septic Arthritis vessels, bone, joints, tendons, or nerves. Furthermore, US can provide image guidance for removal of the foreign bodies. US can show the complications of foreign body infections such as cellulitis, myositis, abscesses, sinus tracts, and vascular or tendon injuries [47].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. All foreign bodies are hyperechoic on US with some degree of posterior acoustic shadowing. A rim of hyperechogenicity may surround the foreign body with increased inflammation and vascularity on color Doppler. This can develop within 24 hours, and it is thought to represent soft tissue granulomatous reaction [47]. Although most superficial foreign bodies are visible on US, deeper locations (>4 cm from the skin) are more difficult to detect on US [46]. It is also difficult to visualize foreign bodies if there is air in the adjacent soft tissues, especially deeper and smaller foreign bodies. US cannot detect foreign bodies within bone.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Variant 7: Suspected soft tissue infection. Initial radiographs show soft tissue gas (without puncture wound) or are normal with high clinical suspicion of necrotizing fasciitis. Next imaging study. For soft tissue infection, the body regions covered are abdomen, neck, ankle, chest, elbow, thigh, foot, forearm, hand, hip, arm, knee, pelvis, shoulder, leg, wrist.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. NF is a rare, rapidly progressive soft tissue infection, which is often difficult to treat and requires surgical intervention with a high mortality rate ranging from 29% to 80% [2,49]. A polymicrobial infection composed of both aerobic and anaerobic organisms is typically seen. The infection causes necrosis by microvascular occlusion along the fascial tissues beginning at the superficial fascia along the subcutaneous soft tissues and then progressing into the deeper fascial layers between muscle planes and compartments [49].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. In addition to the clinical findings of NF, laboratory evaluation can be helpful. A scoring system named Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) is often used, which takes into consideration WBC, hemoglobin, blood chemistry values, and C-reactive protein [50]. Although NF is primarily diagnosed clinically, imaging findings can be critical to support the diagnosis, to aid in surgical planning, and to map disease extent and involvement. However, obtaining imaging studies, such as MRI, should not delay appropriate surgical treatment in patients who are severely ill and unstable [49].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. CT Area of Interest The CT findings in NF correlate with the pathophysiology of the infection causing soft tissue inflammation and liquefactive necrosis. Skin thickening, inflammatory subcutaneous fat stranding, and fluid or gas in the superficial or deep fascial planes are the typical CT findings [49,51,52]. In a study evaluating 20 surgically proven cases of NF, Wysoki et al [53] reported that CT demonstrated subcutaneous fat stranding and fascial fluid or thickening in 80%, soft tissue gas in 55%, and abscesses in 35% of cases. Tso et al [52] concluded that although the overall sensitivity of CT in diagnosing NF is 80%, the specificity is low because similar findings may be present in non- NF, cellulitis, pyomyositis, bursitis, and other soft tissue infections.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Compared with radiography, US, and MRI, CT is the most sensitive modality for detection of soft tissue gas [51,52,54]. Fernando et al [54] reported in a meta-analysis of 23 studies that the visualization of soft tissue gas on radiographs had a sensitivity of 49% and a specificity of 94% for the diagnosis of NF. Soft tissue gas on CT was associated with a sensitivity of 89% and a specificity of 93% for diagnosing NF. Gas within fascial planes and fluid collections is an important finding and can be a CT hallmark of NF; however, the absence of soft tissue gas does not exclude NF [2,49,51,52]. Early in the disease process, especially NF infections with more aerobic organisms, and in diabetic patients, soft tissue gas may not be present or detectable by CT [52].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. In the Fernando et al meta-analysis of NF studies, most CT examinations were performed without IV contrast or the type of CT examination was not specified [52,54]. The evaluation of the use of contrast-enhanced imaging in the medical literature is limited [2]. Carbonetti et al [51] performed a retrospective study investigating 36 selected patients who had contrast-enhanced CT imaging performed and concern for NF or other severe soft tissue infection, which included confirmed patients with NF (10 surgically proven patients), non-NF (2 patients), cellulitis (10 patients), soft tissue abscess (7 patients), myositis (5 patients), and gas gangrene (2 patients). This study concluded that CT findings of fascial fluid and thickening and lack of enhancement of the fascia after CT with IV contrast administration were both highly associated with NF. The Carbonetti et al study reported that more patients with surgically proven NF had absence of fascial enhancement compared with those with other musculoskeletal infections, suggesting that the absence of fascial enhancement was specific for NF [55]. Contrast-enhanced CT imaging also improves the assessment for abscess, tissue necrosis, and vascular complications [6,52].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. However, noncontrast CT is highly accurate for detection of NF [2,49,52,54].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Suspected Osteomyelitis, Septic Arthritis


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. MRI Area of Interest MRI is the modality of choice for detecting superficial or deep fascial fluid or edema [2,49,50,52,56,57]. MRI can recognize small amounts of fluid or edema in the fascia, potentially allowing for earlier diagnosis [54,56]. MRI has the highest reported sensitivity of 93% for the diagnosis of NF because of this detection of fluid signal on T2 fat suppressed or short tau inversion recovery (STIR) sequences [49,52]. Furthermore, the absence of fluid signal along the fascia essentially excludes the diagnosis of NF [2,52,56,57]. However, MRI findings of superficial and deep fascial fluid or edema are not specific for NF and can be seen in other soft tissue infections, such as severe cellulitis and non-NF. If the MRI is negative or with nonspecific findings and there is high clinical suspicion of NF, appropriate surgical treatment should be planned [49]. Also, in stable yet nonimproving patients, obtaining follow- up MRI can be of benefit to assess for progression of necrosis or fascial fluid and edema [49].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Although CT is more sensitive for detecting soft tissue gas, it can be seen as low punctate or curvilinear signal on all MRI sequences (T1-weighted, T2-weighted, STIR) and can be detected with high sensitivity with gradient echo sequences because of blooming artifact and susceptibility artifact. The presence of soft tissue gas is highly associated with NF; however, the absence of soft tissue gas on MRI should not exclude the diagnosis of NF and may be seen in late stages of NF [50,52,56]. Although some degree of fascial thickening, indistinctness of fascial planes, and fluid accumulation can be seen on CT, the MRI high signal intensity appearance of fascial fluid and edema on T2 fat suppression/STIR sequences is far superior for the detection of NF [56]. Yoon et al [50] also compared 2 parameters for diagnosing NF: utilization of the LRINEC score only and when both MRI findings and the LRINEC scores where applied to the diagnostic scenario. When the LRINEC score was used alone, the sensitivity, specificity, positive predictive value, and negative predictive value were 57%, 84%, 77%, and 67%, respectively. Integrating both MRI findings and LRINEC scoring produced values of 77%, 84%, 82%, and 79%, respectively. They concluded that MRI findings improved the overall sensitivity of diagnosing NF.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. There are varying reports regarding the amount of fascial enhancement present based on the stage of necrosis [49,52]. Similar to CT, the assessment of fascial enhancement is controversial. Based upon studies in the MRI literature from >20 years ago, NF fascial enhancement patterns following IV contrast administration are variable with nonenhancement, mixed, and enhancement patterns all reported in the medical literature [2,58]. The presence of fascial enhancement is attributed to increased capillary permeability and IV contrast extravasation. In contrast, the absence of fascial enhancement is attributed to necrosis and microvascular occlusion [2,49,52,58]. In the later stages of NF, focal or diffuse nonenhancement of the fascia may be seen because of necrosis, which can be helpful to differentiate from non-NF [50,52,57]. In general, contrast-enhanced MRI aids in the identification of abscess and areas of necrosis, extent of infection, and delineation of vascular involvement, which can be beneficial in NF [2,49,52].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. However, noncontrast MRI is still an important examination with the highest reported sensitivities to detect soft tissue findings of fascial edema/fluid signal and can detect the known imaging findings of NF to include deep fascial/intermuscular edema, soft tissue gas, and fluid collections [2,49,50,52,56,57].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. US Area of Interest US findings of NF include soft tissue gas, subcutaneous fat edema, and irregular thickening and fluid along superficial and deep fascial planes [52,57,59,60]. A unique benefit to US is the ability to compare the contralateral extremity or other regions of normal tissue. Also, US can evaluate for deep venous thrombosis, provide image guidance for fluid aspiration, use color Doppler, and assess for foreign bodies [52,59]. The US appearance of soft tissue gas is typically an echogenic region or foci along the superficial and/or deep fascia with some degree of incomplete posterior acoustic shadowing. The presence of gas causes the posterior acoustic shadowing, and the changes in echotexture does impede sound penetration which can limit visualization of deeper structures [57]. For NF, this may cause US to have a limited role for the evaluation of the deeper intermuscular fascia especially in larger body habitus patients [52,57]. The subcutaneous fat can be thickened and demonstrate overall increased echogenicity due to fat edema and inflammatory change. Also, the fat lobules can form a cobblestone appearance due to the thickening of subcutaneous fat septa [52,57,59,60]. Although these findings are not specific for NF and


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. can be seen in cellulitis or anasarca, finding irregular thickened fascia and abnormal fluid collections in deeper muscle fascia can help differentiate NF [52,60].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Consistent throughout the US literature is the importance of the detection of fluid accumulation and thickened deep intermuscular fascia for diagnosing NF [52,59-62]. The overall sensitivity of US for the diagnosis of NF varies from 42% to 88%, with a specificity of 70% to 94% [52,59,60]. These variations may be due to the amount of deep fascial thickening and fluid accumulation.


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. There is limited evidence regarding the role of US in the diagnosis of NF [52,57,59,60]. Because CT and MRI are more sensitive modalities for visualizing fluid and fascial thickening, a negative US should not exclude the diagnosis of NF [61]. US has been described useful in diagnosing NF in pediatric patients with thinner, soft tissues causing improved better visualization of the deeper fascial planes [57,61].


Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Suspected Osteomyelitis, Septic Arthritis 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 Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Dysphagia

Dysphagia. Dysphagia affects up to 22% of adults in the primary care setting and is more common in older adults [3,4]. Adults over 65 years of age account for up to two-thirds of all people with dysphagia [3]. Although the aging process is associated with neuromuscular changes, aging itself does not typically cause clinically significant dysphagia. Aging is associated with an increased prevalence of neuromuscular and degenerative disorders that can cause dysphagia; therefore, the presence of dysphagia should prompt evaluation [3,5]. It is also important to recognize that a person may have an asymptomatic swallowing disorder. In one study of 2,000 patients evaluated with videofluoroscopic examinations, 51% of patients were found to aspirate; however, of those who were aspirated, 55% demonstrated silent aspiration with an absent protective cough reflex [6].


Dysphagia

Dysphagia. Reprint requests to: publications@acr.org


Dysphagia

Dysphagia. Pharynx Dynamic and Static Imaging Biphasic examination of the pharynx is performed by acquiring static and dynamic images of the pharynx. Double-contrast and single-contrast images of the pharynx and videofluoroscopy of swallowing are obtained. Pharyngeal function, structure, and motility are also assessed. The structural evaluation of the pharynx is superior to that obtained with a modified barium swallow because fluoroscopic spot images are obtained. Therapeutic maneuvers are not typically performed or assessed in this examination.


Dysphagia

Dysphagia. Biphasic Esophagram A biphasic fluoroscopic evaluation of the esophagus includes single- and double-contrast techniques, including full-column, mucosal relief, and double-contrast views of the esophagus [11]. Esophageal function and motility are evaluated at fluoroscopy. Double-contrast technique provides more mucosal detail compared with the single- contrast technique. However, patient cooperation and mobility are required.


Dysphagia

Dysphagia. Single-Contrast Esophagram A single-contrast esophagram or barium swallow includes full-column distension, mucosal relief views, and fluoroscopic observation of esophageal motility. Single-contrast studies are well suited for elderly, debilitated, obese, and postoperative patients as well as patients who are unable to fully cooperate with the biphasic examination. A single-contrast esophagram may be performed with barium or water-soluble contrast.


Dysphagia

Dysphagia. Discussion of Procedures by Variant Variant 1: Oropharyngeal dysphagia with an attributable cause. Initial imaging. An accurate medical and surgical history from the patient or medical record is helpful to determine the appropriate test to optimally assess the patient. Typical functional and neurologic causes of oropharyngeal dysphagia include recent stroke, worsening dementia, myasthenia gravis, or amyotrophic lateral sclerosis. Many patients with oropharyngeal dysphagia can subjectively localize a sensation of blockage or discomfort in the throat. Patients with oropharyngeal dysphagia typically complain of food sticking in the throat or of a globus sensation with a lump in the throat. Other symptoms of oropharyngeal dysfunction include coughing or choking during swallowing (due to laryngeal penetration or aspiration), a nasal-quality voice or nasal regurgitation (due to soft palate insufficiency), food dribbling from the mouth, and difficulty initiating swallow or chewing (due to an abnormal oral phase of swallowing). It is also important to recognize that abnormalities of the mid or distal esophagus or even the gastric cardia may cause referred dysphagia to the upper chest or pharynx, whereas abnormalities of the pharynx rarely cause referred dysphagia to the lower chest [6]. Therefore, the esophagus and cardia should be evaluated in patients with pharyngeal symptoms, particularly if no abnormalities are found in the pharynx to explain these symptoms [12].


Dysphagia

Dysphagia. Fluoroscopy Pharynx Dynamic and Static Imaging The evaluation of the pharynx with dynamic and static imaging evaluates swallowing function similar to the modified barium swallow. However, this examination typically does not involve a variety of barium consistencies, does not include an evaluation of therapeutic options, and does not evaluate the thoracic esophagus and gastric cardia. Static images aid in evaluation for structural abnormalities of the pharynx.


Dysphagia

Dysphagia. CT Neck and Chest CT is usually not indicated in this clinical scenario because it does not assess oropharyngeal function.


Dysphagia

Dysphagia. Esophageal Transit Nuclear Medicine Scan Scintigraphy is usually not indicated in this clinical scenario because it does not assess the oropharynx.


Dysphagia

Dysphagia. Variant 2: Unexplained oropharyngeal dysphagia. Initial imaging. Patients with unexplained oropharyngeal dysphagia may need a more detailed barium study to determine the cause. Also, because abnormalities of the distal esophagus or gastric cardia can cause referred sensation of dysphagia in the upper chest or pharynx, the esophagus and gastric cardia should be evaluated in patients with pharyngeal symptoms, and a combined radiologic examination of the oral cavity, pharynx, esophagus, and gastric cardia is appropriate for patients with unexplained pharyngeal dysphagia.


Dysphagia

Dysphagia. In patients with unexplained oropharyngeal dysphagia, the combination of videofluoroscopy and static images of the pharynx with an examination of the esophagus has a higher diagnostic value than either videofluoroscopy (such as a modified barium swallow) or static images (such as a biphasic or single-contrast esophagram) alone [17]. If a study is performed using solely static imaging, a biphasic study is preferable to a single-contrast barium swallow because of its superior depiction of mucosal processes.


Dysphagia

Dysphagia. Fluoroscopy Single-Contrast Esophagram Double-contrast technique provides more superior mucosal detail compared with the single-contrast technique. However, patient cooperation and mobility are required and single-contrast technique may be better suited for those patients who are unable to fully cooperate with the biphasic examination, such as elderly, debilitated, and obese patients.


Dysphagia

Dysphagia. Fluoroscopy Barium Swallow Modified A modified barium swallow examination may be of benefit in this setting, particularly if structural abnormalities have been excluded by direct endoscopic visualization. In a study by Madhavan et al [19], a videofluoroscopic


Dysphagia

Dysphagia

Dysphagia. Dysphagia


Dysphagia

Dysphagia. modified barium swallow identified a cause for dysphagia in 76% of patients. Localization of the videofluoroscopic finding to the site of the patients symptoms was accurate in 75% of cases when the finding was structural versus 18% when the finding was physiologic [19].


Dysphagia

Dysphagia. CT Neck and Chest CT is usually not indicated in this clinical scenario as initial imaging because it does not assess oropharyngeal and esophageal mucosa and motility. CT may be helpful in the subsequent evaluation of patients if initial studies are not revealing.


Dysphagia

Dysphagia. Esophageal Transit Nuclear Medicine Scan Nuclear scintigraphy could be used to assess for motility abnormalities or gastroesophageal reflux; however, it is not a substitute for examinations that evaluate the function and structure of the pharynx.


Dysphagia

Dysphagia. Variant 3: Retrosternal dysphagia in immunocompetent patients. Initial imaging. Patients with retrosternal dysphagia experience a sensation of blockage or discomfort at any level between the thoracic inlet and the xiphoid process. Because retrosternal dysphagia can be caused by esophageal motility disorders or by structural abnormalities of the esophagus or cardia (ie, esophagitis, rings, strictures, or tumors), a biphasic esophagram is the preferable imaging procedure.


Dysphagia

Dysphagia. Fluoroscopy Biphasic Esophagram The biphasic esophagram permits detection of both structural and functional abnormalities of the esophagus. Structural lesions include esophagitis, strictures, rings, and carcinoma. Functional abnormalities of the esophagus include gastroesophageal reflux and motility disorders.


Dysphagia

Dysphagia. The most important structural lesion is carcinoma of the esophagus or gastroesophageal junction. In one study, biphasic esophagography was found to have 96% sensitivity in diagnosing cancer of the esophagus or esophagogastric junction [20] comparable to the reported sensitivity of endoscopy for diagnosing these lesions. In two other large patient series, endoscopy failed to reveal any cases of esophageal carcinoma that had been missed on the barium studies [21,22]. The findings in these series suggest that endoscopy is not routinely warranted to rule out missed tumors in patients who have normal findings on radiologic examinations.


Dysphagia

Dysphagia. Although double-contrast views best detect mucosal lesions (eg, tumors, esophagitis), prone single-contrast views of patients who continuously drink a low-density barium suspension best detect lower esophageal rings or strictures. Lower esophageal rings are two to three times more likely to be diagnosed on prone single-contrast views than on upright double-contrast views because of inadequate distention of the distal esophagus when the patient is upright [11,23]. In one study, the biphasic esophagram was found to depict about 95% of all lower esophageal rings, whereas endoscopy detected only 76% of these rings [23]. Similarly, biphasic esophagrams have been found to have a sensitivity of about 95% for the detection of peptic strictures, sometimes revealing strictures that are missed with endoscopy [24,25].


Dysphagia

Dysphagia. The biphasic esophagram is also a useful test in patients with esophageal motility disorders causing dysphagia. Videofluoroscopy of discrete swallows of a low-density barium suspension in the prone right antero-oblique position permits detailed assessment of esophageal motility. In various studies, videofluoroscopy has been found to have an overall sensitivity of 80% to 89% and specificity of 79% to 91% for diagnosing esophageal motility disorders (eg, achalasia, diffuse esophageal spasm) compared with esophageal manometry [17,26]. Occasionally, barium studies may even reveal dysmotility not seen at manometry (eg, some patients with the beak-like distal esophageal narrowing of achalasia are found to have complete relaxation of the lower esophageal sphincter on manometry) [27]. Even for those patients with a significant esophageal motility disorder detected on a barium study, manometry may be performed to further elucidate the nature of this motility disorder.


Dysphagia

Dysphagia. Endoscopy performed to evaluate the esophagus for structural abnormalities in patients with dysphagia is a highly accurate test for esophageal cancer when multiple endoscopic biopsy specimens and brushings are obtained. It is also more sensitive than double-contrast esophagography for detecting mild reflux esophagitis or other subtle forms of esophagitis. However, endoscopy is a much more invasive test than the barium study. It is also less sensitive than the barium study for detecting lower esophageal rings or strictures [11,23-25] and does not permit evaluation of esophageal motility disorders. For these reasons, a biphasic esophagram is often recommended as the initial diagnostic test for patients with dysphagia [3,5,28].


Dysphagia

Dysphagia. Dysphagia Fluoroscopy Single-Contrast Esophagram Although the biphasic esophagram provides superior mucosal detail, allowing for earlier detection of subtle lesions, patient cooperation and mobility are required. For debilitated, immobile patients or patients who are limited in their ability to cooperate, a single-contrast esophagram may be necessary.


Dysphagia

Dysphagia. Fluoroscopy Barium Swallow Modified In patients with retrosternal dysphagia, the entire esophagus and the gastric cardia should be assessed. Therefore, the modified barium swallow may not be appropriate.


Dysphagia

Dysphagia. Fluoroscopy Pharynx Dynamic and Static Imaging Dynamic and static imaging of the pharynx may not be appropriate as the only examination performed in a patient with retrosternal dysphagia because the entire esophagus and gastric cardia should be assessed. This study does not evaluate the thoracic esophagus or gastric cardia.


Dysphagia

Dysphagia. CT Neck and Chest CT is not usually indicated as an initial imaging modality in this clinical scenario because it does not assess esophageal mucosa and motility. CT may be helpful in the subsequent evaluation of patients if initial studies are not revealing.


Dysphagia

Dysphagia. Esophageal Transit Nuclear Medicine Scan Specific protocols to assess esophageal emptying may be useful in patients with known or suspected achalasia but does not provide anatomic detail [29,30]. Radionuclide esophageal transit scintigraphy is a simple, noninvasive, and quantitative test of esophageal emptying that can be useful in these patients [3,31,32].


Dysphagia

Dysphagia. Variant 4: Retrosternal dysphagia in immunocompromised patients. Initial imaging. The major consideration in immunocompromised patients with dysphagia or odynophagia (painful swallowing) is infectious esophagitis, most commonly due to Candida albicans or herpes simplex virus. In HIV-positive patients, Candida is most often the cause of esophageal symptoms; cytomegalovirus, herpes simplex, and idiopathic ulcers (also known as HIV ulcers) are the other most common etiologies [33]. HIV-positive patients with esophageal symptoms may be treated empirically with antifungal therapy without first undergoing a diagnostic examination. However, most gastroenterologists prefer that those who have severe symptoms at presentation or persistent symptoms be evaluated by endoscopy. Endoscopy is preferred because of the ability to obtain specimens (eg, histology, cytology, immunostaining, or culture) [3,33]. The endoscopic or radiographic appearance alone usually does not accurately predict diseases other than Candida esophagitis; diagnosis requires specimen acquisition for laboratory study [33,34].


Dysphagia

Dysphagia. Fluoroscopy Biphasic Esophagram Esophagrams are preferred by some as an initial diagnostic study and can be useful in guiding management. A biphasic esophagram is more accurate than single-contrast esophagram for detecting ulcers or plaques associated with infectious esophagitis [35-37]. However, a single-contrast esophagram may be performed if the patient is too sick or debilitated to tolerate a double-contrast examination. Patients with radiographically diagnosed Candida or herpes esophagitis may be treated with antifungal or antiviral agents, respectively, without endoscopic evaluation. Endoscopy is warranted for patients with giant esophageal ulcers to differentiate cytomegalovirus and HIV and begin appropriate therapy [34].


Dysphagia

Dysphagia. Fluoroscopy Single-Contrast Esophagram Although the biphasic esophagram provides superior mucosal detail, allowing for earlier detection of subtle lesions, patient cooperation and mobility are required. For debilitated, immobile patients or patients who are limited in their ability to cooperate, a single-contrast esophagram may be necessary.


Dysphagia

Dysphagia. Fluoroscopy Barium Swallow Modified A modified barium swallow does not evaluate esophageal anatomy and structure. It may not be appropriate because it may fail to reveal the etiology of retrosternal dysphagia. However, it may be useful to evaluate swallowing function in the setting of pharyngeal infection.


Dysphagia

Dysphagia. Fluoroscopy Pharynx Dynamic and Static Imaging Dynamic and static imaging evaluates swallowing and oropharyngeal motility and structure. Performed alone, it may not be appropriate because it may fail to reveal the etiology of retrosternal dysphagia.


Dysphagia

Dysphagia. Dysphagia CT Neck and Chest CT is usually not indicated as an initial imaging modality in this clinical scenario because it does not assess esophageal mucosa and motility. CT may be helpful in the subsequent evaluation of patients if initial studies are not revealing.


Dysphagia

Dysphagia. Esophageal Transit Nuclear Medicine Scan Scintigraphy is usually not indicated in this clinical scenario.


Dysphagia

Dysphagia. Variant 5: Early postoperative dysphagia. Oropharyngeal or retrosternal. Initial imaging. Dysphagia is a common complaint following surgery on the oropharynx, soft tissues of the neck, cervical spine, esophagus, or stomach. Imaging should be tailored to the type and location of surgery (oropharyngeal versus retrosternal) and the time of onset of symptoms following surgery. In the immediate or early postoperative period, fluid collections, anastomotic leaks, perforation, and abscess may be of clinical concern [38].


Dysphagia

Dysphagia. Fluoroscopy Single-Contrast Esophagram A single-contrast esophagram is the study of choice for patients presenting with dysphagia following surgery to the neck, c-spine, esophagus, or stomach [1,39]. When there is a question of leak or fistula, the study is ideally performed by utilizing water-soluble contrast followed by barium if necessary.


Dysphagia

Dysphagia. Esophagrams are highly specific for the detection of leaks but not sensitive. Roh et al [39] showed that the sensitivity of the esophagram in diagnosing a leak was 36% and specificity was 97%. For this reason, a CT examination may be ordered if there is a high clinical suspicion following a negative esophagram. Lantos et al [40] showed that esophagography had a sensitivity of 79%, specificity of 73%, positive predictive value of 73%, and negative predictive value of 79% for detecting leaks, and esophagography and CT combined had a sensitivity of 100%, specificity of 27%, positive predictive value of 56%, and negative predictive value of 100%. The sensitivity of esophagography increased when high-density barium was administered after water-soluble contrast, whereas the sensitivity of CT was the same with and without oral contrast agent. Esophagrams have a slightly lower sensitivity and substantially higher specificity compared with CT for detecting leaks after esophagectomy [41].


Dysphagia

Dysphagia. Fluoroscopy Biphasic Esophagram Biphasic esophagram is not usually indicated when a patient has dysphagia in the immediate postoperative period. Single-contrast technique utilizing water-soluble contrast is preferable because evaluation for postoperative leak is the primary concern.


Dysphagia

Dysphagia. Fluoroscopy Barium Swallow Modified When oropharyngeal dysphagia occurs postoperatively and there is a high index of suspicion for swallowing dysfunction, a modified barium swallow is the study of choice, especially if leak has been excluded clinically or with imaging.


Dysphagia

Dysphagia. In the immediate postoperative period, if a leak or perforation is of clinical concern, a single-contrast esophagram with water-soluble contrast may be more appropriate because it is better suited to evaluate postoperative structural abnormalities. However, a modified swallow performed with water-soluble contrast material has been shown to be effective in the diagnosis of leakage [41]. In this study there were no adverse events associated with aspiration of iohexol as water-soluble contrast material [41]. A modified barium swallow examination does not evaluate the entire esophagus. It is not appropriate for postoperative retrosternal dysphagia because it does not evaluate the retrosternal anatomy.


Dysphagia

Dysphagia. Fluoroscopy Pharynx Dynamic and Static Imaging Pharynx dynamic and static imaging is usually not appropriate because it is a double-contrast barium evaluation of the pharynx alone. A single-contrast esophagram with water-soluble contrast possibly followed with barium is more appropriate to evaluate for postoperative leak or fistula in a patient who has had surgery in the neck and is complaining of oropharyngeal dysphagia [42]. Furthermore, this study does not evaluate the thoracic esophagus and gastric cardia. Alone, pharynx dynamic and static imaging is not appropriate for postoperative retrosternal dysphagia because it does not evaluate the retrosternal anatomy but may be useful combined with esophageal evaluation.


Dysphagia

Dysphagia. CT Neck and Chest For oropharyngeal and retropharyngeal dysphagia, CT of the neck and chest with intravenous (IV) contrast is


Dysphagia

Dysphagia

Dysphagia. Dysphagia


Dysphagia

Dysphagia. indicated when there is concern of early postoperative complications, such as leak, fluid collection, abscess, or hematoma [40,43]. CT has a slightly higher sensitivity and substantially lower specificity than esophagography for detecting clinically relevant leaks after esophagectomy [40,43]. The use of CT as the initial imaging test in these patients can lead to earlier diagnosis and treatment of leaks missed on esophagography. In many patients, both CT and esophagrams are performed especially when the clinical concern is high. Lantos et al [40] showed that esophagography had a sensitivity of 79%, specificity of 73%, positive predictive value of 73%, and negative predictive value of 79% for detecting leaks, whereas CT had a sensitivity of 86%, specificity of 33%, positive predictive value of 55%, and negative predictive value of 71%; esophagography and CT combined had a sensitivity of 100%, specificity of 27%, positive predictive value of 56%, and negative predictive value of 100%.


Dysphagia

Dysphagia. CT may be useful to assess the position of surgical hardware or complication related to surgical hardware with respect to the oropharynx and airway. Oral contrast administered immediately before the examination may be a helpful adjunct to facilitate interpretation of esophageal integrity and anatomy, though one study showed the use of oral contrast did not change the sensitivity of CT for detection of leaks [40].


Dysphagia

Dysphagia. CT scan with IV contrast better defines the anatomic structures of the neck and chest compared to CT without IV contrast because normal soft-tissue and blood vessel enhancement are better delineated from postoperative fluid collections, such as hematomas and abscesses.


Dysphagia

Dysphagia. Obtaining a CT scan with and without IV contrast offers little additional benefit compared to a CT with IV contrast alone.


Dysphagia


Dysphagia

Dysphagia. Variant 6: Delayed (greater than 1 month) postoperative development of dysphagia. Oropharyngeal or retrosternal. Initial imaging. Dysphagia occurring weeks or months following surgery may be due to dysmotility, gastroesophageal reflux, or structural abnormalities, such as anastomotic strictures, diverticula, or recurrent disease [38]. The incidence of dysphagia after laryngectomy is reported to occur in up to 72% of patients [44], and aspiration occurs in 65% of patients [45]. In addition to patients who have undergone operations to the oropharynx, larynx, and esophagus, operative procedures on the cervical spine may also cause dysphagia and significant disability. In the latter group of patients, dysphagia may be caused by structural abnormalities (displaced surgical hardware or bone graft) or functional abnormalities resulting in aspiration or penetration [1]. Patients following esophageal and gastric surgery can also experience dysphagia related to many potential complications.


Dysphagia

Dysphagia. Fluoroscopy Pharynx Dynamic and Static Imaging Pharynx dynamic and static imaging is usually not appropriate because it is a double-contrast barium evaluation of the pharynx alone. A single-contrast esophagram with water-soluble contrast possibly followed with barium is more appropriate to evaluate for postoperative leak or fistula in a patient who has had surgery in the neck and is complaining of oropharyngeal dysphagia [42]. Furthermore, this study does not evaluate the thoracic esophagus


Dysphagia

Dysphagia. and gastric cardia. Alone, pharynx dynamic and static imaging is not appropriate for postoperative retrosternal dysphagia because it does not evaluate the retrosternal anatomy but may be useful combined with esophageal evaluation.


Dysphagia

Dysphagia. 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.


Dysphagia

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


Lower Extremity Arterial Revascularization Post Therapy Imaging. Over the past several decades, a paradigm shift away from surgical treatment and toward endovascular therapy for PAD has occurred, with many now advocating surgical treatments only after one or more failed endovascular revascularization attempts. The BASIL trial demonstrated that patients with critical limb ischemia (CLI) presenting with rest pain, ulceration, and gangrene of the leg due to infrainguinal disease had similar amputation- free survival and quality-of-life outcomes whether they were randomized to a surgery-first or angioplasty-first treatment strategy. Furthermore, first-year costs associated with bypass surgery were about one-third higher than those associated with angioplasty [5]. The long-term outcomes following surgical and endovascular therapy in the setting of CLI are the subject of the ongoing BEST-CLI trial, which has an estimated primary endpoint completion date in December 2018.


Lower Extremity Arterial Revascularization Post Therapy Imaging. Whether endovascular or surgical revascularization is used, restenosis is a pervasive issue. As target lesion restenosis and adjacent segment disease typically precede frank occlusion and CLI, surveillance has been advocated for many years in the setting of bypass, and there is increasing evidence to support its use following angioplasty and stenting. Additionally, there has been a steady increase in the investigative tools available to the vascular specialist to diagnose and stratify lesions in the lower extremity arteries. Because of the plethora of testing options available, it can be difficult for physicians to determine the most appropriate test to obtain in the setting of recurrent symptoms after therapy.


Lower Extremity Arterial Revascularization Post Therapy Imaging. Overview of Imaging Modalities Noninvasive Hemodynamic Testing Noninvasive testing (NIVT), both before and after intervention, has been used for decades as a first-line investigatory tool in the diagnosis and categorization of PAD. It is widely available and provides a large amount of information at low cost without the use of ionizing radiation [6]. NIVT can consist of one or more of the following components: the ABI, segmental pressure measurements (SPMs), pulse-volume recordings (PVRs), photoplethysmography (PPG), and transcutaneous oxygen pressure measurement (TcPO2).


Lower Extremity Arterial Revascularization Post Therapy Imaging. aResearch Author, University of Michigan Health System, Ann Arbor, Michigan. bPrincipal Author and Panel Vice-chair, University of Michigan Health System, Ann Arbor, Michigan. cPanel Chair, UT Southwestern Medical Center, Dallas, Texas. dScripps Green Hospital, La Jolla, California; Society for Vascular Surgery. eNorthwestern Medicine, Chicago, Illinois. fUniversity of Wisconsin, Madison, Wisconsin. gMassachusetts General Hospital, Boston, Massachusetts. hCleveland Clinic Heart and Vascular Institute, Cleveland, Ohio; American College of Cardiology. iMayo Clinic, Rochester, Minnesota. jUniversity of Michigan Health System, Ann Arbor, Michigan. kUniversity of California San Diego, San Diego, California. lUniversity of Virginia Health System, Charlottesville, Virginia. mLoyola University Medical Center, Maywood, Illinois. nColumbia University Medical Center, New York, New York. oUT Southwestern Medical Center, Dallas, Texas. pSpecialty Chair, Ottawa Hospital Research Institute and the Department of Radiology, The University of Ottawa, Ottawa, Ontario, Canada.


Lower Extremity Arterial Revascularization Post Therapy Imaging. 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.


Lower Extremity Arterial Revascularization Post Therapy Imaging. Reprint requests to: publications@acr.org


Lower Extremity Arterial Revascularization Post Therapy Imaging. PVRs provide a qualitative (rather than quantitative) measurement of limb perfusion. PVRs are created by inflating pneumoplethysmography cuffs to a specified pressure at predetermined levels on each limb. Each cuff measures the miniscule change in the volume of the limb under the cuff with each pulse, creating a tracing of volume versus time. The resultant waveforms can be compared to determine segmental disease, providing insight into the quality of arterial blood flow at each station simultaneously. PVRs are also useful in patients with noncompressible vessels, as this modality relies on limb volume change rather than the pressure required impeding flow through the vessel being interrogated.


Lower Extremity Arterial Revascularization Post Therapy Imaging. PPG involves the detection of a transmitted infrared signal through each of the digits. The degree of transmitted signal varies depending on blood volume within the digit, blood vessel wall movement, and the orientation of red blood cells [12]. PPG is useful for detection of disease below the knee as well as disease isolated to the forefoot and digits. As such, it has been demonstrated to be a complementary test to ABI, which has limited use in these segments.


Lower Extremity Arterial Revascularization Post Therapy Imaging. TcPO2 measurement allows the determination of the oxygen tension within tissue. An improvement in the TcPO2 value postintervention compared with preintervention has been validated as an excellent marker of tissue reperfusion [13]. TcPO2 values >40 mmHg in the area surrounding the ulcer or amputation site are considered predictive of successful healing. This test is not limited by noncompressible vessels, and, in patients without pedal Doppler signals, it is one of the few NIVTs that is helpful [14]. The test is limited by its availability in the office setting, patient resistance to avoiding smoking and caffeine prior to the test, as well as the time and cost constraints associated with providing the temperature-controlled environment required to standardize the test.


Lower Extremity Arterial Revascularization Post Therapy Imaging. US Peripheral duplex ultrasound (DUS) imaging, which consists of grayscale 2-D imaging, color Doppler, and spectral waveform analysis, has been a mainstay of vascular imaging for decades. This technology is widely available, portable, does not require contrast agents, and can be used in the angiography suite or operating room. DUS has been validated as a screening tool [15], a first-line study for clinically suspected PAD [16], and as a tool to plan the approach for both endovascular and surgical intervention [17]. In most situations, it is complimentary to NIVT, such as the ABI [18]. US has a high sensitivity for the detection of patent tibial arteries but is less accurate in detecting complete occlusions, particularly in the peroneal artery [19]. DUS has also been used to quantify the firmness of occlusions to determine the degree of chronicity to some success [20].


Lower Extremity Arterial Revascularization Post Therapy Imaging. Lower Extremity Arterial Revascularization correlate well with symptom recurrence [26]. When planning interventions, the anticipated intervention based on US alone was unchanged after angiogram in femoropopliteal and iliac lesions in >80% of patients, but only 59% in lesions below the knee [27]. In critical limbs, close surveillance shows significant improvement in limb salvage rates over clinical follow-up alone [28].


Lower Extremity Arterial Revascularization Post Therapy Imaging. Unfortunately, of all the noninvasive imaging techniques, US is also the most operator dependent and time consuming [29]. The DIPAD trial, which evaluates the cost-benefit ratio of DUS compared with computed tomography angiography (CTA) and contrast-enhanced magnetic resonance angiography (CE-MRA), showed that although the initial cost of US is lower, this does not take into account the time-related expense and operator experience required to produce satisfactory imaging. Additionally, practitioner confidence in the results is often lower than with the more advanced techniques, leading to a greater number of follow-up studies prior to intervention [30].


Lower Extremity Arterial Revascularization Post Therapy Imaging. CTA Modern CTA has been demonstrated to be comparable to the gold standard (catheter-based angiography) for the detection of hemodynamically significant stenoses (>50%) with sensitivity, specificity, and accuracy of 99%, 98%, and 98%, respectively [31]. Refinements in CT protocols have also compared favorably to MRA with no statistically significant difference between the two modalities in the evaluation of claudication or CLI [32]. Arterial opacification is significantly improved by using high-density compact contrast boluses, which is rapidly becoming the standard of care with equivalent iodine dose to previous standard bolus technique [33].


Lower Extremity Arterial Revascularization Post Therapy Imaging. Potential drawbacks of CTA include the exposure to ionizing radiation and the use of iodinated contrast, which presents the potential for allergic reaction or contrast-induced nephropathy, particularly in those patients who already possess some degree of renal impairment. Metallic streak artifact is often problematic in patients with postsurgical changes or implanted hardware. Additionally, in extremely obese patients, the signal-to-noise ratio becomes somewhat prohibitive. Evaluation of densely calcified vessels can be difficult with CTA because of the similar density between plaque and contrast and the blooming artifact created by the former, leading to overestimation of the degree of stenosis in many cases, as well as the inability to determine patency in stented vessels. Because of the density of calcified plaque in relation to the relatively small lumen of the tibial vessels, CTA has traditionally suffered in the infrageniculate distribution [34].


Lower Extremity Arterial Revascularization Post Therapy Imaging. Multiple studies have now validated dual-energy CTA as a practical and effective method for subtraction of calcified plaque and soft tissues, allowing for simultaneous creation of conventional CTA data sets and angiogram-like composite images of the vasculature alone. These subtraction images have been demonstrated to be nearly equivalent in diagnostic accuracy to those of conventional angiograms, with similar or less radiation using newer protocols [35]. This technique has been improved at some institutions by subtracting the extravascular tissues in multiple segments rather than the entire study at once [36]. Relatively recent advances in CTA technology include the use of dynamic (time-resolved) imaging of the tibial arteries [37], selective ultra- low-dose intra-arterial contrast-enhanced CTA [38], and CO2-enhanced high-pitch CTA [39], all of which show promise in certain circumstances.


Lower Extremity Arterial Revascularization Post Therapy Imaging. MRA MRA has been used for many years in patients with PAD for both treatment planning and assessment of procedural success. Continued evolution of this technology and imaging protocols has improved image quality and increased the potential applications. Most MRA protocols provide both source images with excellent soft- tissue differentiation and subtracted images demonstrating the vasculature in 2-D and 3-D representations similar to those provided during conventional angiography.


Lower Extremity Arterial Revascularization Post Therapy Imaging. In the current era, the accuracy of CTA and CE-MRA for the detection of hemodynamically significant PAD has become essentially equivalent, with an edge for CTA in the aortoiliac segment and for MRA in the infrageniculate distribution [32]. In diabetics, MRA is considered particularly helpful for runoff evaluation because of its superior ability to detect flow in small, calcified vessels, approaching the sensitivity of digital subtraction angiography (DSA) [40].


Lower Extremity Arterial Revascularization Post Therapy Imaging. Lower Extremity Arterial Revascularization


Lower Extremity Arterial Revascularization Post Therapy Imaging. at which each segment is optimally opacified [42]. This technique increases sensitivity, specificity, and accuracy for PAD in all segments of the lower extremity arteries, but most importantly below the knee [43,44]. Time- resolved imaging of the whole limb has also been reported [45]. MRA provides imaging quality similar to DSA for the evaluation of lower extremity bypass conduits [46,47]. It also allows for excellent evaluation of previously angioplastied segments and has a high specificity for in-stent patency; however, sensitivity for occlusion is still poor because of blooming artifact, particularly in stainless steel stents [48]. Newer generation nitinol stents are less affected by this limitation.


Lower Extremity Arterial Revascularization Post Therapy Imaging. There are several important limitations of MRA. Patients with most types of defibrillators, spinal cord stimulators, intracerebral shunts, cochlear implants, and other devices are excluded, as are patients affected by claustrophobia that is not overcome by sedation. Open-field 1.0T MRA has been used for claustrophobic patients, with imaging quality approaching that of DSA above the knee; however, below the knee, the technology is still quite limited [49]. It takes longer to acquire images with MRA than with CTA, and the studies themselves are considerably more expensive. However, with MRA, patients are not exposed to ionizing radiation, and the risk of nephrotoxicity from gadolinium-based contrast is considerably less than that of iodinated contrast agents.


Lower Extremity Arterial Revascularization Post Therapy Imaging. For a time, CE-MRA was considered an alternative to CTA in patients with renal impairment; however, since the association between renal failure and nephrogenic systemic fibrosis after gadolinium administration was discovered, it fell out of favor [50]. This led to copious research of noncontrast MRA. Time-of-flight imaging is one such method, which, with current technology, provides images with equivalent accuracy to CE-MRA for popliteal and runoff assessment, but still lags behind in the aortoiliac and femoral segments [51,52]. It is less expensive than CE-MRA, and has been proposed as a potential PAD screening test [53]. Quiescent-interval single-shot MRA and flow-spoiled fresh-blood imaging are newer techniques, which may show promise in combination with conventional time-of-flight techniques [54-56]. Quiescent-interval single-shot currently provides similar imaging quality and diagnostic accuracy to CE-MRA in runoff vessels of diabetics, suggesting that perhaps a combination of noncontrast MRA techniques may provide equivalent whole-body vascular imaging to those provided by CE-MRA [57].


Lower Extremity Arterial Revascularization Post Therapy Imaging. Many newer techniques in MRA show excellent promise in certain circumstances. Perfusion imaging using arterial spin labeling has been used to quantify arterial flow in the thigh and calf musculature, which has been shown to have equal or greater sensitivity for PAD compared with ABI, independent of the amount of preimaging exercise time [58,59]. Arterial peak flow velocity measurements can be obtained using phase-contrast techniques, comparing well to those obtained using spectral Doppler [60,61]. The vessel wall itself can be evaluated using blood-suppression, allowing for quantification and characterization of plaque and restenosis [62]. Continuous table movement MRA is a newer method that promises similar imaging quality to conventional multi-station MRA, with 30% faster imaging acquisition [63].


Lower Extremity Arterial Revascularization Post Therapy Imaging. Arteriography DSA is the reference standard to which CTA and MRA are compared. DSA can localize and quantify obstructive lesions, permits physiological evaluation by the determination of pressure gradients, and allows for intervention at the time of diagnosis. In high-acuity settings, such as a thrombosed bypass graft, where immediate catheter-based intervention is likely to be indicated, direct referral to catheter angiography is a valid option. However, DSA is an invasive technique with a small but definite risk in every patient. Access-site hematoma, arterial dissection, thrombosis, and limb loss are known complications that can result from the procedure and occur in up to 2.0% of patients in this population [64]. These occur less frequently with increasing operator experience. For this document, it is assumed the procedure is performed and interpreted by an expert. Serious systemic complications are also possible, with increased risk in patients with severe widespread vascular disease, diabetes, renal insufficiency, or other contraindications to the use of iodinated contrast media. Carbon dioxide angiography may be of value in these patients. In light of the risk of nephrogenic systemic fibrosis in patients with severe renal disease, gadolinium chelates serve a very limited role as DSA contrast agents. Although DSA remains the gold standard for diagnosing PAD at the time of intervention, it generally plays no role in the surveillance of arterial segments previously treated with endovascular methods and in grafts without clinical evidence of malfunction.


Lower Extremity Arterial Revascularization Post Therapy Imaging. Discussion of Procedures by Variant Variant 1: Previous infrainguinal endovascular therapy or bypass. Asymptomatic. Surveillance. The most important indicator of restenosis or occlusion in the setting of previous revascularization is recurrence of symptoms. There is limited data to suggest that treatment of asymptomatic patients after endovascular therapy


Lower Extremity Arterial Revascularization Post Therapy Imaging. Lower Extremity Arterial Revascularization provides any long-term benefit [65]. As such, patients presenting to the clinic for follow-up of previous endovascular therapy or bypass for PAD should be evaluated for symptoms of claudication and rest pain, and should be examined closely for evidence of lower extremity ulceration or gangrene. ABI should be determined at each follow-up visit in all previously treated patients with PAD [66]. PVRs can provide insight into subtle changes in arterial flow quality between segments, often preceding detectable anatomic changes on other modalities; however, they are fraught with reader subjectivity, poor patient cooperation, and baseline abnormalities in poor cardiac output [9]. A recent paper has also called into question whether they provide any benefit over ABIs and SPMs alone [67].


Lower Extremity Arterial Revascularization Post Therapy Imaging. MRA Although both CE-MRA and nonenhanced MRA have been proposed as potential screening tests for PAD, particularly in patients in whom NIVT is limited (ie, diabetics) and time constraints remain prohibitive [77], there is no convincing evidence in the literature arguing for the use of CE-MRA or nonenhanced MRA for surveillance of previously treated PAD, either with endovascular or surgical methods. False positives suggesting recurrent disease in asymptomatic patients could lead to unnecessary procedures.


Lower Extremity Arterial Revascularization Post Therapy Imaging. CTA Because of availability, the use of ionizing radiation and the risks inherent to iodinated contrast, CTA is not recommended for routine follow-up of asymptomatic patients with nonaneurysmal PAD.


Lower Extremity Arterial Revascularization Post Therapy Imaging. Arteriography As an invasive test, lower extremity arteriography is completely inappropriate for surveillance of asymptomatic patients. There is no evidence to support its use in this setting.


Lower Extremity Arterial Revascularization Post Therapy Imaging. Lower Extremity Arterial Revascularization US DUS has a very high correlation with clinical deterioration after both endovascular therapy and bypass for lower-extremity PAD [26]. Following angioplasty, DUS has been validated as accurate for determining the specific levels of hemodynamically significant disease, although it often underestimates the extent of disease beyond the first significant stenosis. The aortoiliac segment can be evaluated in some patients, although obesity and bowel gas artifact are a pervasive problem. In combination with spectral Doppler, inflow disease can often be excluded and can guide the interventional approach (ie, retrograde contralateral versus antegrade ipsilateral access). Duplex is valuable in the determination of flow within and beyond stented and stent-grafted segments, and is slightly less limited than CTA and MRA, particularly in smaller-caliber stents [22]. The identification and treatment of symptomatic restenosis associated with a previously treated segment has been shown to provide improved long-term outcomes and patency in both endovascular and surgical patients [79]. In many cases, patients can proceed directly to intervention with Duplex arterial mapping alone [16,17]. In the setting of bypass, Duplex can determine whether the graft is patent, threatened, or occluded, and often can identify specific segments of disease to guide either endovascular repair or surgical revision.


Lower Extremity Arterial Revascularization Post Therapy Imaging. Although nonenhanced MRA can provide imaging quality and diagnostic confidence levels similar to that from CE-MRA, protocols and image quality vary significantly between institutions. Additionally, the lack of time- resolved imaging limits evaluation in the infrageniculate segment. Its use is generally reserved for patients who require evaluation of suspected aortoiliac and femoropopliteal lesions in the setting of renal insufficiency. The use of this modality is likely to evolve over the next decade given the vast amount of research in this area over the past few years.


Lower Extremity Arterial Revascularization Post Therapy Imaging. CTA In the era of modern CTA, vascular imaging quality is similar to that of DSA, albeit with a modest limitation in the infrageniculate distribution due to contrast-timing issues and the frequency of tibial calcification. Through the acquisition of isotropic voxels on new scanners, images can be reconstructed in any plane, including curved planar reformats along the lumen of the vessel [80]. Particularly suited for aortoiliac and femoropopliteal evaluation, CTA is an excellent choice for the evaluation of claudicants, in which tibial disease is both less frequently present and less frequently treated. Similar to MRA, it is best suited in combination with tests providing data on the hemodynamic significance of identified lesions (NIVT and DUS).


Lower Extremity Arterial Revascularization Post Therapy Imaging. Arteriography Given the similar sensitivity and specificity of MRA and CTA compared with DSA, this invasive modality is generally reserved for immediate pretreatment evaluation of PAD and is rarely used solely for diagnostic purposes. The ability to acquire pressure measurements can help determine whether a previously identified stenosis is truly hemodynamically significant, which can sometimes be difficult to determine with NIVT and DUS in the setting of multilevel disease. It is occasionally used to determine surgical targets for infrageniculate bypass in patients with densely calcified runoff vessels who are deemed to be poor endovascular candidates, although noninvasive cross-sectional imaging has essentially replaced angiography for this indication as well.


Lower Extremity Arterial Revascularization Post Therapy Imaging. Lower Extremity Arterial Revascularization Variant 3: Previous infrainguinal endovascular therapy or bypass, presenting with cold, painful extremity and diminished pulses (acute limb ischemia). Initial imaging. Physical examination is critical in suspected acute limb ischemia/threatened limb, which is, at its core, a clinical diagnosis. The temperature and appearance of the limb, absence of palpable pulses or arterial signals by Doppler, loss of sensation, and decreased or absent strength in the affected extremity all provide insight into the urgency of the event. There is little evidence regarding the use of imaging in the setting of a threatened limb, and no tests should be performed that would significantly delay therapy in a patient with impending limb loss. Patients with severe ischemia, as indicated by motor loss or severe sensory deficits (Rutherford class IIb or III), should likely proceed directly to definitive therapy, usually surgical thromboembolectomy or bypass [81]. Although a full spectrum of NIVT may be too time consuming in an acutely threatened limb, the determination of the ABI and SPM can assist in the determination of both the etiology of the symptoms and can also guide the level of necessary intervention.


Lower Extremity Arterial Revascularization Post Therapy Imaging. US DUS may provide the ability to determine whether the patient has an acute event associated with a previously treated segment or not. Brief evaluation of the venous system can also exclude other potential causes for acute lower extremity ischemia, such as phlegmasia cerulea dolens. Limited US evaluation for the evaluation of bilateral common femoral patency, the determination of inflow quality, and the patency of lower extremity bypass conduits can help guide expeditious treatment. Given portability and ubiquity in the hospital system, this can potentially be performed by physicians in the emergency department to triage patients to appropriate vascular specialists [82]. For this document, it is assumed the procedure is performed and interpreted by an expert. There is increasing focus on training vascular specialists to perform point-of-care DUS to quickly determine the etiology and extent of limb ischemia during the initial consultation [83]. This is particularly true for bypass conduits, which are generally located superficially and easily assessed sonographically. However, these tests should not delay definitive therapy if it is immediately available.


Lower Extremity Arterial Revascularization Post Therapy Imaging. Arteriography Immediately threatened limbs (Rutherford class IIb and early presentations of class III) require rapid definitive therapy, and generally should proceed directly to emergency thromboembolectomy to prevent limb loss [84]. In the setting of viable or marginally threatened limbs (Rutherford class I or IIa), immediate arteriography for the evaluation of anatomic relationships between diseased segments is the preferred procedure [85]. Angiography provides detailed and accurate information regarding the etiology and extent of the insult that has caused acute limb ischemia and may allow a catheter-based treatment in some patients [86]. This can allow patients to be appropriately triaged to either surgery or endovascular therapy, the latter of which may involve thrombolysis or percutaneous thrombectomy, angioplasty, stenting, etc. If performed without prior NIVT or US, there is the potential for longer procedure times, increased contrast use and possibly multiple access sites to provide definitive therapy.


Lower Extremity Arterial Revascularization Post Therapy Imaging. CTA In patients with acute limb ischemia and viable or marginally threatened limbs, CTA may be considered for preprocedural evaluation given its near-equivalent accuracy compared to diagnostic angiography [36]. CTA is a rapid modality that can provide insight into the precise location of vessel occlusion, and in some centers it is supplanting arteriography as the test of choice prior to intervention [87]. It is particularly useful in patients who present with bilateral symptoms where inflow disease is suspected. However, its use should not delay definitive therapy. Additionally, the use of iodinated contrast agent for this modality can limit the ability to provide subsequent angiographic therapy because of the risk of contrast-induced nephropathy [88].


Lower Extremity Arterial Revascularization Post Therapy Imaging. Similar to CE-MRA, nonenhanced MRA is time consuming and should only be used in patients with renal insufficiency where the determination between endovascular and surgical therapy remains obscure.


Lower Extremity Arterial Revascularization Post Therapy Imaging. Although there are references that report on studies with design limitations, 28 well-designed or good-quality studies provide good evidence.


Lower Extremity Arterial Revascularization Post Therapy Imaging. Supporting Documents For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Rib Fractures

Rib Fractures. Introduction/Background Rib fracture is the most common thoracic injury and is present in 10% of all traumatic injuries and in almost 40% of patients who sustain severe nonpenetrating trauma [1,2]. Rib fractures typically affect the fifth through ninth ribs. This may be due to the fact that the shoulder girdle affords relative protection to the upper ribs, and the lower ribs are relatively mobile and may deflect before fracturing [1].


Rib Fractures

Rib Fractures. Although rib fractures can produce significant morbidity, the diagnosis of associated complications (such as pneumothorax, hemothorax, pulmonary contusion, atelectasis, flail chest, cardiovascular injury, and injuries to solid and hollow abdominal organs) is arguably more important as these complications are likely to have the most significant clinical impact [1,2]. When isolated, rib fractures have a relatively low morbidity and mortality [2,3].


Rib Fractures

Rib Fractures. Treatment of rib fractures is generally aimed at pain control and avoidance of respiratory distress and intubation, but the presence of multiple rib fractures, underlying organ injury, or in an elderly patient especially, may warrant transfer from a community hospital to tertiary care center [2,4-6].


Rib Fractures

Rib Fractures. Radiography Chest In combination with the physical examination, a standard posteroanterior (PA) chest radiograph should be the initial diagnostic test for detection of rib fractures. Despite the low sensitivity of the chest radiograph, which may miss 50% of rib fractures [2], studies suggest that failure to detect fractures does not necessarily alter patient management or outcome in uncomplicated cases. A review of 271 patients who presented to a community hospital emergency department after minor trauma showed no difference in treatment (use of pain medications, etc) between patients who did and did not have rib fractures diagnosed on physical examination or radiographs [3]. In a study of 552 patients who had blunt chest trauma and resultant rib fracture (diagnosed on clinical or radiographic grounds), 93% of affected patients ultimately resumed daily activities without significant disability [2]. The chest radiograph may detect complications that are more important than the rib fractures themselves, such as pneumothorax, hemothorax, flail chest, or contusion [1,2]. Although a flail chest can usually be diagnosed at physical examination, it is conceivable that in a heavy patient a flail chest could be missed by clinical examination, but a chest radiograph almost always shows the displaced fragments.


Rib Fractures

Rib Fractures. Dual-energy chest radiography with bone subtraction imaging has failed to show improved detection when


Rib Fractures

Rib Fractures. aPanel Vice-Chair, University of California San Francisco, San Francisco, California. bPanel Chair, Vanderbilt University Medical Center, Nashville, Tennessee. cCharles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida. dSouthern Illinois University School of Medicine, Springfield, Illinois; Society of Thoracic Surgeons. eUniversity of Iowa, Iowa City, Iowa; Society of Thoracic Surgeons. fMayo Clinic, Rochester, Minnesota. gUniversity of Michigan Medical Center, Ann Arbor, Michigan. hUniversity of Iowa Hospitals and Clinics, Iowa City, Iowa. iVanderbilt University Medical Center, Nashville, Tennessee; American College of Chest Physicians. jRadiology Imaging Associates, Englewood, Colorado. kUniversity of Texas Health Science Center at San Antonio, San Antonio, Texas. lJohn H. Stroger, Jr. Hospital of Cook County, Chicago, Illinois; American College of Physicians. mNational Institutes of Health, Bethesda, Maryland. nUniversity of Texas MD Anderson Cancer Center, Houston, Texas. oSpecialty Chair, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.


Rib Fractures

Rib Fractures. Reprint requests to: publications@acr.org


Rib Fractures

Rib Fractures. Rib Fractures compared with standard radiographs. A review of 39 patients with a total of 204 rib fractures showed no statistically significant difference in sensitivity, specificity, or level of confidence between standard images and dual-energy subtraction images [9].


Rib Fractures

Rib Fractures. Radiography Rib Views While still performed in many practices, rib detail radiograph series rarely add additional information to the PA film that would change treatment as has been shown in two retrospective studies. In a review of 422 patients presenting to a university-affiliated emergency department for suspected rib fracture, Shuaib et al [10] found that rib series resulted in a change of management in only one patient (0.23%). Moreover, these authors found that, compared to standard PA radiographs, rib series negatively impacted patient care by prolonging report turnaround time [10].


Rib Fractures

Rib Fractures. Hoffstetter et al [11] retrospectively reviewed 609 patients that underwent rib series in the emergency department and found that while diagnosing a higher number of rib fractures as compared to PA radiographs alone, there was no statistically significant difference in the number of patients who received medical treatment. If rib series are to be performed, Park et al [12] showed that interpreting images with both conventional grayscale and inverted grayscale views may improve detection of rib fractures, although this study did not assess if the improved detection had an effect on outcomes.


Rib Fractures

Rib Fractures. CT Chest The increased sensitivity of CT for the detection of rib fractures does not necessarily alter the management or clinical outcomes of patients without associated injuries. Kea et al [13] reported that CT detected rib fractures in 66 of 589 patients (11%) who had initial chest radiographs interpreted as normal at a level I trauma center, but none of the rib fractures were considered of major clinical significance.


Rib Fractures

Rib Fractures. The presence and number of rib fractures, and the degree of displacement of the fractures, may carry prognostic significance. Thus, detection of rib fractures by CT may be indicated under certain circumstances (especially if severe injury is suspected). Bugaev et al [14] retrospectively reviewed 245 patients that presented to a level 1 trauma center for a number of rib fractures and degree of displacement. They found that the number of rib fractures and the degree of fracture fragment displacement accurately predicted subsequent opioid requirements.


Rib Fractures

Rib Fractures. Patients with rib fractures from a high-energy mechanism or with a high clinical suspicion of intrathoracic or intra-abdominal injury may warrant further evaluation with contrast-enhanced CT, whereas a low-energy injury or normal physical examination may obviate further testing. Dubinsky and Low [17] studied 69 patients with nonthreatening trauma (stable vital signs with no evidence of cardiac injury, solid or hollow viscus rupture, or fractures associated with significant blood loss) and found that neither rib studies nor chest radiographs were of clinical benefit in this scenario, but they concluded that clinical evidence of a complicated injury, such as pneumothorax, hemothorax, or flail chest, may warrant further evaluation.


Rib Fractures

Rib Fractures. Similarly, Schurink et al [18] studied patients with lower rib fractures (ribs 7 through 12) and found that the negative predictive value of a negative physical examination for abdominal injury that is due to low-energy impact was 100%, but in patients with multiple injuries, lower rib fractures were associated with abdominal organ injury in 67% of patients. Matthes et al [19] found no association between right-sided lower rib fractures in 55


Rib Fractures

Rib Fractures. Rib Fractures trauma patients with hepatic injury when matched with 55 trauma patients without hepatic injury (there was a slight negative association of hepatic laceration with left-sided fractures) but ultimately concluded that the absence of rib fractures could not rule out hepatic injury. Thus, in patients with multiple injuries and lower rib fractures, contrast-enhanced CT might be indicated even in the setting of a normal clinical examination.


Rib Fractures

Rib Fractures. Several studies have demonstrated a high prevalence of radiographically detected rib fractures in patients with aortic injury, although the positive predictive value is low. In a large prospective multicenter trial involving 50 trauma centers in North America, Fabian et al [20] reported multiple rib fractures in 46% of 274 patients with blunt aortic injury. Mirvis et al [21] found fractures of ribs 1 through 4 in 18% of 41 patients with traumatic aortic injury proved by angiography but with a positive predictive value of only about 21%. Lee et al [22] studied 548 patients who underwent angiography to evaluate for aortic injury and concluded that rib fractures were the only type of thoracic skeletal injury that had a higher incidence in patients with aortic injury (58%) versus those without aortic injury (43%), but the positive predictive value was only 14.8%. This has also been shown at autopsy, where Williams et al [23] retrospectively reviewed 530 motor vehicle fatalities. In 90 victims, 105 aortic injuries were found, and 78% had multiple rib fractures, including 42% with fractures of the first rib.


Rib Fractures

Rib Fractures. In contrast, there is some evidence that rib fractures detected with CT (given the increased sensitivity) may not be associated with an increased risk of aortic injury. A review of 185 patients with rib fractures detected on spine CT found no association between presence of first-rib or second-rib fracture and the incidence of aortic injury on subsequent CT [24]; however, ribs 3 through 12 were not assessed. Increased likelihood of injury to the adjacent subclavian and innominate vessels has been reported with displaced first-rib and second-rib fractures, but this injury can usually be suspected on clinical grounds or from a chest radiograph [25].


Rib Fractures

Rib Fractures. US Chest Several articles have noted that ultrasound (US) can detect fractures not seen on conventional radiographs [26- 28]. Griffith et al [28] compared US and radiography (chest radiography plus one oblique rib radiograph) in 50 patients and found that radiographs detected only 8 of 83 (10%) sonographically detected rib fractures and were positive in only 6 of the 39 patients who had demonstrated fractures. In this study, US allowed evaluation of the costochondral junction, the costal cartilage, and the ribs and was able to show nondisplaced fractures.


Rib Fractures

Rib Fractures. Kara et al [26] found rib fractures in 40.5% of 37 patients with minor blunt chest trauma and negative radiographs by using US; osseous fractures were more common in the elderly, and duration of pain was significantly longer in these patients compared to those with chondral injuries [26-28]. However, Hurley et al [29] found US to be only marginally superior to conventional radiographs, and its routine use was not indicated because of the lengthy time of the examination, averaging 13 minutes in this series, and patient discomfort from the pressure of the US probe, particularly since identification of the fracture was unlikely to impact patient care.


Rib Fractures

Rib Fractures. Bone Scan Whole Body Nuclear medicine bone scans are sensitive but not specific for detection of rib fracture [30]. Bone scans are most commonly used for detection of osseous involvement in systemic processes (eg, metastatic disease) and may result in false-positive diagnosis of malignancy in a patient with rib fractures, although the pattern of tracer uptake can often help differentiate the two processes [30]. Bone scans have limited use in distinguishing acute and subacute or chronic rib fractures as they will usually be positive within 24 hours after an injury, but the return to normal can be slow (79% by 1 year, 93% by 2 years, and 100% in 3 years) [31]. Furthermore, patients with known malignancy and benign rib fractures may exhibit false-positive findings on PET using the tracer fluorine- 18-2-fluoro-2-deoxy-D- glucose (FDG) studies performed 17 days to 8 weeks after injury [32].


Rib Fractures

Rib Fractures. Variant 2: Suspected rib fractures after cardiopulmonary resuscitation (CPR). Initial imaging. Radiography Chest Multiple studies [33-35] have shown that rib fractures are under-reported on radiography performed following cardiopulmonary resuscitation (CPR). In a retrospective analysis of 40 patients who survived CPR, Kim et al [33] reported that CT detected rib fractures in 26 patients (65%); whereas, anteroposterior chest radiography detected fractures in only 10 of the patients. Lederer et al [34] found that radiography detected only 14% of rib fractures compared to autopsy in 19 patients.


Rib Fractures

Rib Fractures. Rib fractures from CPR are more commonly anterior, on the left side, and are more numerous in the elderly [34]. The diagnosis of such fractures in CPR survivors may be important since approximately half of CPR survivors with rib fractures experience complications, and the presence of rib fractures in these patients may impair