MRI is an excellent imaging modality for the evaluation of inflammatory disease of the rectum or IPAA. Using IV contrast material enhances the ability to diagnose inflammation, adding the findings of mucosal hyperenhancement to other findings such as wall thickening, submucosal edema seen on T2-weighted sequences, and mucosal ulceration. Additional findings, such as perirectal and perianal fistula and abscess, can also be seen. In a study of 58 patients with CD who had MRI and colonoscopy, several MRI features correlated with endoscopic diagnosis of proctitis, including wall thickness, submucosal fat, increased perimural signal intensity on T2-weighted sequences, increased perimural enhancement, creeping fat, and mesorectal lymph node size [54]. In another study of 9 patients, MRI had sensitivity and specificity of 100% for pouchitis as validated by pathology, using the criteria of increased wall thickness and enhancement [55]. Radiography Pelvis Radiography is not useful in this clinical scenario because it cannot assess inflammation of the rectum or ileoanal pouch. There is no relevant literature to support the use of radiography in the evaluation of suspected proctitis or pouchitis. US Pelvis Various US techniques (transabdominal, transperineal, transvaginal, and endorectal) can be used to assess the rectum or IPAA. In one study using endorectal US to evaluate radiation proctitis as compared with colonoscopy, endorectal US had sensitivity of 86.4%, specificity of 66.7%, PPV of 76.0%, NPV of 80.0%, and overall accuracy of 77.5% in differentiating mild from severe radiation proctitis by using blurred rectal wall stratification and wall vascularity [56]. There is no relevant recent literature regarding the use of US in the evaluation of suspected pouchitis. WBC Scan Abdomen and Pelvis In 1990, Thoeni et al [57] published a retrospective study of 55 patients who underwent total colectomy and IPAA.
Anorectal Disease. MRI is an excellent imaging modality for the evaluation of inflammatory disease of the rectum or IPAA. Using IV contrast material enhances the ability to diagnose inflammation, adding the findings of mucosal hyperenhancement to other findings such as wall thickening, submucosal edema seen on T2-weighted sequences, and mucosal ulceration. Additional findings, such as perirectal and perianal fistula and abscess, can also be seen. In a study of 58 patients with CD who had MRI and colonoscopy, several MRI features correlated with endoscopic diagnosis of proctitis, including wall thickness, submucosal fat, increased perimural signal intensity on T2-weighted sequences, increased perimural enhancement, creeping fat, and mesorectal lymph node size [54]. In another study of 9 patients, MRI had sensitivity and specificity of 100% for pouchitis as validated by pathology, using the criteria of increased wall thickness and enhancement [55]. Radiography Pelvis Radiography is not useful in this clinical scenario because it cannot assess inflammation of the rectum or ileoanal pouch. There is no relevant literature to support the use of radiography in the evaluation of suspected proctitis or pouchitis. US Pelvis Various US techniques (transabdominal, transperineal, transvaginal, and endorectal) can be used to assess the rectum or IPAA. In one study using endorectal US to evaluate radiation proctitis as compared with colonoscopy, endorectal US had sensitivity of 86.4%, specificity of 66.7%, PPV of 76.0%, NPV of 80.0%, and overall accuracy of 77.5% in differentiating mild from severe radiation proctitis by using blurred rectal wall stratification and wall vascularity [56]. There is no relevant recent literature regarding the use of US in the evaluation of suspected pouchitis. WBC Scan Abdomen and Pelvis In 1990, Thoeni et al [57] published a retrospective study of 55 patients who underwent total colectomy and IPAA.