Detection and characterization of perianal inflammatory disease: accuracy of transperineal combined gray scale and color Doppler sonography.

OBJECTIVE: To evaluate the accuracy of transperineal gray scale and color Doppler sonography for the detection and characterization of perianal inflammatory disease with surgical correlation. METHODS: Eighty-seven patients with suspected perianal inflammatory disorders underwent transperineal gray scale and color Doppler sonography with a linear 4- to 7-MHz transducer that was used to scan the entire perianal region for the detection of suspected inflammatory disorders. Each detected inflammatory disorder was evaluated to determine its morphologic characteristics and extent. Color Doppler sonography was applied to assess the presence of increased vascularity in the perianal region. In comparison with surgical findings, the diagnostic performance of transperineal sonography was assessed by means of receiver operating characteristic analysis for lesion detection and the Spearman rho test for lesion characterization. Logistic regression analysis was used to assess whether increased perineal vascularity was a predictive factor of perianal inflammatory disease. RESULTS: Seventy-seven perianal inflammatory disorders were confirmed in 62 patients. Gray scale sonography achieved a significantly good performance in the detection (area under the curve = 0.86; P < .001) and characterization (r = 0.65; P < .001) of perianal inflammatory disease. For the detection of perianal fistulas and abscesses, sensitivity was 100% for both, and specificity was 100% and 94%, respectively. With the use of color Doppler sonography, the diagnostic confidence increased slightly (area under the curve = 0.89) but significantly (P = .002). Logistic regression analysis identified hypervascularity at the periphery of a perianal lesion as a significant independent predictor of an inflammatory disease. CONCLUSIONS: Combined gray scale and color Doppler sonography enables a high detectability rate and comprehensive characterization of perianal abscesses and fistulas.