Location also affects diagnosis in which higher sensitivities for terminal ileal involvement are seen compared with more proximal small bowel [87]. False-positive diagnoses of abscesses are more likely at US [97]. Radiography Abdomen Radiographs of the abdomen are limited in the evaluation of an acute flare or complication of CD. The ability to directly visualize bowel pathology is limited, and evidence for CD is instead inferred indirectly. There is little role for radiographs if the patient is not acutely ill. Radiographs may be useful in severely ill presenting patients for presence of bowel perforation or evidence for obstruction. Crohn Disease Fluoroscopy Small-Bowel Follow-Through and Fluoroscopic Enteroclysis Historically, fluoroscopic contrast examinations of the gastrointestinal tract have been the primary imaging methods of choice in the evaluation of CD. SBFT (with or without per oral pneumocolon) and enteroclysis can be used to evaluate the small bowel for evidence of thickening and active disease [50,79]. In addition, internal fistulas can be detected [80], although other extramural complications, such as abscess formation are only indirectly visualized, which leads to decreased detection [27]. It has become evident; however, with the emergence of specialized cross- sectional imaging modalities, that the performance of contrast fluoroscopy is not as accurate for active disease compared with these other examinations [18,42,46,81,82]. Both SBFT and enteroclysis are hampered by their 2-D perspective, whereby pathology can be obscured because of overlapping bowel loops [18,82,83]. On the other hand, the real-time assessment for a fixed versus pliable nature of a segment of bowel can provide important ancillary information. Depending on institutional and surgeon preference, there may be a role in delineating the preoperative anatomy for the surgeon, although there has been a marked decline in fluoroscopic use over recent years.
Crohn Disease. Location also affects diagnosis in which higher sensitivities for terminal ileal involvement are seen compared with more proximal small bowel [87]. False-positive diagnoses of abscesses are more likely at US [97]. Radiography Abdomen Radiographs of the abdomen are limited in the evaluation of an acute flare or complication of CD. The ability to directly visualize bowel pathology is limited, and evidence for CD is instead inferred indirectly. There is little role for radiographs if the patient is not acutely ill. Radiographs may be useful in severely ill presenting patients for presence of bowel perforation or evidence for obstruction. Crohn Disease Fluoroscopy Small-Bowel Follow-Through and Fluoroscopic Enteroclysis Historically, fluoroscopic contrast examinations of the gastrointestinal tract have been the primary imaging methods of choice in the evaluation of CD. SBFT (with or without per oral pneumocolon) and enteroclysis can be used to evaluate the small bowel for evidence of thickening and active disease [50,79]. In addition, internal fistulas can be detected [80], although other extramural complications, such as abscess formation are only indirectly visualized, which leads to decreased detection [27]. It has become evident; however, with the emergence of specialized cross- sectional imaging modalities, that the performance of contrast fluoroscopy is not as accurate for active disease compared with these other examinations [18,42,46,81,82]. Both SBFT and enteroclysis are hampered by their 2-D perspective, whereby pathology can be obscured because of overlapping bowel loops [18,82,83]. On the other hand, the real-time assessment for a fixed versus pliable nature of a segment of bowel can provide important ancillary information. Depending on institutional and surgeon preference, there may be a role in delineating the preoperative anatomy for the surgeon, although there has been a marked decline in fluoroscopic use over recent years.