SONOGRAPHIC APPEARANCE OF BENIGN AND MALIGNANT CONDITIONS OF THE COLON

OBJECTIVE. The objective of this study was to compare the sonographic appearance of different abnormalities of the colon to evaluate the rol e of sonography in their differential diagnosis. MATERIALS AND METHODS . We retrospectively reviewed videotaped sonographic examinations of 9 9 patients with proven diagnoses that included diverticulitis (n = 35) , malignancy (n = 20), Crohn's disease (n = 16), pseudomembranous coli tis (n = 14), ischemic colitis (n = 9), and ulcerative colitis (n = 5) , Data were collected with regard to gut features, including the site of colonic involvement, associated small-bowel involvement, length of diseased segment, stratification, luminal contents, pneumatosis, and d iverticula. Perigut features evaluated included abnormal fat, abscess, fistula, and ascites. RESULTS. On sonography, the following features were statistically significant (p < .05). Involvement of the small bow el was more common in patients with Crohn's disease than in the remain der of the study population (44% versus 1%). Left-sided colonic diseas e (91% versus 38%), diverticula (91% versus 3%), and perigut findings (91% versus 57%), including abnormal fat (83% versus 39%) and abscess (34% versus 8%), were features that indicated diverticulitis. Malignan t conditions were more common in patients with a greater wall thicknes s (mean, 26.2 mm versus 10.2 mm), asymmetric involvement (85% versus 3 9%), loss of stratification (85% versus 20%), absence of perigut findi ngs (65% versus 22%), and involvement of a short diseased segment (70% versus 16%). Involvement of the entire colon (50% versus 2%), luminal contents (64% versus 28%), and ascites (64% versus 26%) were features suggesting pseudomembranous colitis. CONCLUSION. Although the sonogra phic appearances of abnormalities of the colon overlap, some sonograph ic features are helpful in the differential diagnosis of colonic abnor malities.