Comparing histopathological and magnetic resonance imaging based mesorectal fascia status in patients with rectal carcinoma.

OBJECTIVE To compare mesorectal fascia status on histopathological findings with MRI based radiological mesorectal fascia status in patients with rectal carcinoma taking histopathology finding as gold standard. STUDY DESIGN Analytical study. PLACE AND DURATION OF STUDY Department of Pathology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, from January 2011 to April 2012. METHODOLOGY Biopsy proven cases of rectal adenocarcinoma undergoing abdominoperineal resection were included in this study. Microscopic examination of slides was done to determine mesorectal fascia status as involved or otherwise without knowing the results of mesorectal fascia status on MRI. Mesorectal fascia status of MRI was determined by a radiologist who was not aware of the histopathological assessment of mesorectal fascia. Mean and standard deviation was calculated for age. Frequency and percentage were calculated for gender and mesorectal fascia status. 2 x 2 table was generated to calculate sensitivity, specificity, positive predictive value and negative predictive values and diagnostic accuracy of MRI for mesorectal fascia involvement taking histopathology as gold standard. RESULTS The sensitivity of MRI to detect mesorectal fascia involvement was 23.07% and specificity was 70.5%. Positive predictive value of MRI was 10% and negative predictive value was 54.54%. Diagnostic accuracy of MRI for mesorectal fascia involvement was calculated as 50%. CONCLUSION MRI findings regarding mesorectal fascia status as involved or otherwise are not helpful when compared with histopathological findings which is the gold standard.