However, the overall diagnostic performance for CT enterography is excellent. When an endoscopic standard is utilized, sensitivity for CD ranges from 75% to 90%, with a specificity of >90% [24-27]. Compared with other imaging modalities, CT enterography represents an optimal option for most patients [21,27-31]. The diagnosis of acute inflammation is made through visualization of thickened small bowel with mural stratification as well as extraenteric processes including engorged vasa recti/vasculature and surrounding inflammatory stranding [25,26,32-34]. Because CT enterography is a cross-sectional imaging modality, assessment for alternative diagnoses, as well for the possible complications of CD including obstruction, abscess, and fistula, can be made [28,35-37]. With its intrinsic high spatial resolution and reproducible quality, state-of-the-art CT enterography represents one of the main imaging methods for initial diagnosis of small-bowel CD. At many United States medical centers and practices, a combination of CT enterography and ileocolonoscopy has been advocated as the diagnostic algorithm of choice at initial presentation [38]. Ileocolonoscopy can assess for colonic and distal ileal involvement and permits biopsies. The addition of CT enterography allows for assessment of the entire small bowel, including the distal ileum, and is helpful in establishing a CD diagnosis in cases in which the terminal ileum and colon are not involved or when intramural disease is predominant, which may not be apparent at endoscopy. For this variant in which the patient does not have an established diagnosis for CD and other entities remain in the differential, the cross-sectional/global nature of this CT-based modality allows potential diagnosis of an entity mimicking a CD presentation and adds to the utility of CT enterography. Ultimately, the decision to select CT enterography versus a standard CT abdomen and pelvis examination is dependent on the acuity and severity of presentation.
Crohn Disease. However, the overall diagnostic performance for CT enterography is excellent. When an endoscopic standard is utilized, sensitivity for CD ranges from 75% to 90%, with a specificity of >90% [24-27]. Compared with other imaging modalities, CT enterography represents an optimal option for most patients [21,27-31]. The diagnosis of acute inflammation is made through visualization of thickened small bowel with mural stratification as well as extraenteric processes including engorged vasa recti/vasculature and surrounding inflammatory stranding [25,26,32-34]. Because CT enterography is a cross-sectional imaging modality, assessment for alternative diagnoses, as well for the possible complications of CD including obstruction, abscess, and fistula, can be made [28,35-37]. With its intrinsic high spatial resolution and reproducible quality, state-of-the-art CT enterography represents one of the main imaging methods for initial diagnosis of small-bowel CD. At many United States medical centers and practices, a combination of CT enterography and ileocolonoscopy has been advocated as the diagnostic algorithm of choice at initial presentation [38]. Ileocolonoscopy can assess for colonic and distal ileal involvement and permits biopsies. The addition of CT enterography allows for assessment of the entire small bowel, including the distal ileum, and is helpful in establishing a CD diagnosis in cases in which the terminal ileum and colon are not involved or when intramural disease is predominant, which may not be apparent at endoscopy. For this variant in which the patient does not have an established diagnosis for CD and other entities remain in the differential, the cross-sectional/global nature of this CT-based modality allows potential diagnosis of an entity mimicking a CD presentation and adds to the utility of CT enterography. Ultimately, the decision to select CT enterography versus a standard CT abdomen and pelvis examination is dependent on the acuity and severity of presentation.