Preoperative local staging of rectal cancer with endorectal MR imaging Comparison with histopathologic findings Oguz Akin a, *, Gurel Nessar b , Ahmet Muhtesem Agildere b , Gulden Aydog c a Department of Radiology, School of Medicine, Baskent University, Fevzi Cakmak Cad., 10. Sok., No:45, Bahcelievler, 06490 Ankara. Turkey b Department of Gastroenterological Surgery, Turkiye Yuksek Ihtisas Egitim ve Arastirma Hastanesi, Sy ´hhiye, Ankara. Turkey c Department of Pathology, Turkiye Yuksek Ihtisas Egitim ve Arastirma Hastanesi, Sy ´hhiye, Ankara. Turkey Received 20 September 2003 Abstract The purpose of this prospective study was to assess the accuracy of endorectal MR imaging in the preoperative local staging of rectal cancers. In 20 cases, we correlated endorectal MR imaging findings with postoperative histopathologic staging according to TNM classification. The accuracy of endorectal MR for determining the T stage of rectal cancer was 85%. The sensitivity and specificity for detecting lymph node metastases were 90.9% and 55.5%, respectively. D 2004 Elsevier Inc. All rights reserved. Keywords: Rectal cancer; MR Imaging; Colorectal carcinoma 1. Introduction Colorectal carcinoma is the most common cancer of the gastrointestinal tract and the second most common cause of cancer-related death in the United States [1,2]. Radical surgery remains the treatment of choice for resectable rectal cancers; however, in recent years, there has been consider- able interest in less extensive surgical methods and preop- erative radiation treatment. The goals of local surgery are preservation of the anal sphincter, low morbidity, low hospital costs, and better quality of life for the patient. In order to select the most appropriate treatment for each case, the preoperative work-up must determine the regional spread of the tumor through the rectal wall and the nodal status [3–6]. The introduction of the endorectal coil has greatly improved the resolution in MR imaging. Endorectal coils allow higher signal to noise ratio with a smaller field of view compared to body coils. Therefore, with this tech- nique, precise identification of the layers of the rectal wall is possible. Our purpose in this study was to assess the effectiveness of endorectal MR imaging for local staging of rectal cancer before surgery. Using the endorectal surface coil MR imaging technique preoperatively, we observed for tumor infiltration of the rectal wall layers, adjacent organ invasion, and lymph node involvement. This assessment was compared with findings on histopathologic examination of surgical specimens. 2. Materials and methods 2.1. Patients and study design IRB approval and informed consents from the patients were obtained for this prospective study. From December 1999 to August 2001, 23 patients with rectal cancer were preoperatively evaluated with endorectal MR imaging. All the subjects had been diagnosed with rectal adenocarcinoma based on colonoscopic biopsy between 1 and 3 weeks before MR imaging. We were able to obtain images adequate for local staging in 21 of the 23 cases. In one patient, the endo- rectal coil was not placed appropriately due to stiff oblit- eration of the rectal lumen by the tumor. In the other case with unsatisfactory images, the neoplasm extended beyond the scope of the endorectal coil. One patient whose endo- rectal MR images were satisfactory for local staging refused surgery. These three patients were excluded from the study. 0899-7071/04/$ – see front matter D 2004 Elsevier Inc. All rights reserved. doi:10.1016/S0899-7071(03)00314-0 * Corresponding author. 1233 York Avenue, 15-Q, New York, NY 10021, USA. E-mail address: akinoguzdr@yahoo.com (O. Akin). Journal of Clinical Imaging 28 (2004) 432 – 438