AJR:187, September 2006 W275 AJR 2006; 187:W275–W284 0361–803X/06/1873–W275 © American Roentgen Ray Society M E D I C A L I M A G I N G A C E N T U R Y O F M E D I C A L I M A G I N G A C E N T U R Y O F Hoeffel et al. MRI of Rectal Disorders Gastrointestinal Imaging • Pictorial Essay MRI of Rectal Disorders Christine C. Hoeffel 1 Louisa Azizi 1 Najat Mourra 2 Maïté Lewin 1 Lionel Arrivé 1 Jean-Michel Tubiana 1 Hoeffel CC, Azizi L, Mourra N, Lewin M, Arrivé L, Tubiana J-M Keywords: colon, gastrointestinal radiology, MRI DOI:10.2214/AJR.05.0508 Received March 23, 2005; accepted after revision June 7, 2005. 1 Department of Radiology, Université Paris-Descartes Faculté de Medecine Cochin Port-Royal, Hôpital Saint- Antoine, 184 Rue du Faubourg, Saint-Antoine 75571, Paris cedex 12, France. Address correspondence to C. C. Hoeffel (christine.hoeffel@sat.ap-hop-paris.fr). 2 Department of Pathology, Hôpital Saint-Antoine, Saint- Antoine 75571, Paris cedex 12, France. CME This article is available for 1 CME credit. See CME data for this article at http://www.arrs.org/scriptcontent/ajr/ ajrcme/index.cfm for more information. WEB This is a Web exclusive article. OBJECTIVE. The objective of this pictorial essay is to provide a review of the diseases involving the rectal wall with an emphasis on the key clinical and radiologic differentiating features. CONCLUSION. A wide spectrum of disease processes can involve the rectum in adults. MRI is the technique of choice in the definitive diagnosis of these disease conditions, mainly because of its superior tissue contrast differentiation. he rectum is the part of the gas- trointestinal tract in which MRI studies are the most successful. The superb soft-tissue contrast and multiplanar imaging capability of this technique helps in characterizing rectal disor- ders and permits visualizing the perirectal area. MRI has primarily been used to study rectal carcinoma and to assess involvement from tumors of pelvic origin. But MRI has an important role to play in a number of nonneo- plastic rectal diseases in adults, including congenital and developmental diseases, in- flammatory and infectious diseases, vascular diseases, and lesions of endometriosis. Accu- rate diagnosis of these conditions is crucial because it can significantly alter clinical man- agement. The aim of this pictorial essay is to review the diseases involving the rectal wall, highlighting the main clinical or radiologic differentiating features. Congenital and Developmental Lesions Developmental Cysts Developmental cysts mostly occur in mid- dle-aged women. They are asymptomatic in 50% of cases, but patients may present with symptoms resulting from local mass effect or with complications such as infection, bleeding, or malignant degeneration. Enteric cysts, de- fined as cysts partially or completely lined with intestinal mucosa (tailgut cysts and rectal du- plication), are the most frequent. They may im- pinge on the rectum or be intimately attached to the rectal wall. Cystic rectal duplication is rare, representing 5% of all developmental cysts, but is the only cystic lesion defined by continuity or contiguity with the rectum. An enteric cyst typically appears as a well-de- fined, unilocular or multilocular, thin-walled, homogeneous lesion that is hypointense on T1- weighted images and hyperintense on T2- weighted images and nonenhancing. High sig- nal intensity on T1-weighted images is likely to result from mucoid content in a tailgut cyst. The cyst may be thick-walled with surround- ing inflammatory changes [1] (Fig. 1). Diffuse Cavernous Hemangioma This rare, benign vascular malformation consists of an extensive network of vascular lakes involving the entire intestinal wall, which may infiltrate into the surrounding connective tissue. Clinical and radiologic clues include a history of chronic rectal bleeding in young adults, a moderately high T2-weighted signal intensity, a markedly thickened rectosigmoid wall, and high-signal-intensity heterogeneous perirectal fatty tissue with enhancing serpigi- nous structures—small vessels supplying the malformation [2] (Fig. 2). Diffuse cavernous hemangioma may extend to perirectal tissue, including pelvic musculature. Inflammatory and Infectious Conditions Idiopathic inflammatory bowel disease ac- counts for the majority of inflammatory and in- fectious cases. The findings may often be non- specific, and ancillary clinical information usually leads to the most probable diagnosis. When the diagnosis has been established, MRI will be useful to assess the extent and severity of the disease and to identify complications. T Downloaded from www.ajronline.org by 52.73.204.196 on 05/16/22 from IP address 52.73.204.196. Copyright ARRS. For personal use only; all rights reserved