Comparative study between ultrasound biomicroscopy and histopathology of diversion colitis on rats

An ultrasound biomicroscopic image system, using a 50 MHz PVDF transducer (f-number = 1.5, focal distance = 4.4 mm, -6 dB bandwidth of 31.2 MHz), was employed as a complementary method to improve the diagnosis and to characterize the course and severity of diversion colitis. Nine SPF Wistar rats, Rattus norvegicus (Berkenhout, 1769), were randomly distributed into groups I- Control, II and III-Hartmann´s colostomy. Tissue samples comprised the distal colon (n=3) for group I and the excluded segment excised 8 weeks in group II (n=3) and 25 weeks in group III (n=3), after colostomy. UBM images of each sample, in rectangular fragments of 5times5 mm, were obtained. Mucosa, lamina propria, submucosa and muscular layers were identified in the UBM images and morphologically correlated with the histology of the samples from group I. UMB images from group II revealed morphologically preserved muscle layer and enlarged lamina propria and submucosa (due to an edema associated with leukocyte infiltration of the lamina propria). Extensive mucosa atrophy was found in group III. The morphological results found in ultrasound images for groups I, II and III are similar to those obtained by histological examinations.