Value of DW-MRI ADC quantification of colonic wall lesions in differentiation of inflammatory bowel disease and colorectal carcinoma

The purpose of our study was to assess the efficiency of diffusion-weighted magnetic resonance imaging (DW-MRI) and the quantification of apparent diffusion coefficient (ADC) values in differentiating colorectal carcinoma from colonic inflammatory bowel disease (IBD) in cases with isolated colonic wall lesions and uncertain clinical and radiologic diagnostic criteria. The study comprised 58 patients with segmental or focal isolated colonic wall thickening. All lacked satisfactory clinical-radiological findings for etiology determination. The mean ADC values of the thickened colonic walls were retrospectively compared with final histopathologic diagnoses. Receiver operating characteristic (ROC) curve analysis was used to determine the ADC cutoff value for differentiation. Mean ADC value in the colorectal carcinoma group was significantly lower than that in the IBD group: n = 27, 1.02 +/- A 0.26 x 10(-3) mm(2)/s; and n = 31, 1.53 +/- A 0.19 x 10(-3) mm(2)/s, respectively (P < 0.001). Cutoff ADC value for differentiating colorectal carcinoma from IBD was calculated as 1.39 x 10(-3) mm(2)/s, with 83.9 % sensitivity and 85.2 % specificity. ADC measurement of the involved colonic wall segments with DW-MRI has the potential to differentiate isolated colonic IBD from colorectal carcinoma in cases in which clinical-radiologic findings are insufficient for a definitive diagnosis.