Title : Role of magnetic resonance imaging in local staging of rectal carcinoma
Abstract:
Background: The purpose of this study is to evaluate the role of Magnetic Resonance Imaging in staging rectal carcinoma.
Methods: 27 biopsy proved cases of rectal carcinoma were subjected to pelvic MRI on 3.0T system (Discovery 750w, GE, Milwaukee, Wisconsin, USA). T1W, T2W and DW sequences were done in axial, sagittal and coronal plane (planes defined in reference to tumor). Then 0.01mmol/kg of gadolinium based contrast was injected intravenously and T1W sequences were done in all three planes. Tumor was evaluated for location (distance from anal verge as well as circumferential location), size, morphology, distance from anorectal junction, mucinous/non-mucinous, relation to anterior peritoneum, involvement of adjacent organs, vessels, nerves, lymph nodes, pelvic floor, anal sphincters, mesorectal fascia (MRF) and any metastasis. Tumors were staged and risk assessed based on these. The outcome was compared to surgical histopathological findings, per rectal/colonoscopy findings and follow-up.
Results: Patients ranged from 32-72 year with mean age of 56 years. 13 patients were stage IV, 8 stage III, 6 stage II while there was no case in stage I. 22 patients were in high risk, 4 in intermediate risk and 1 in low-risk category. Out of total 27 patients 24 patients (89%) showed good correlation between MRI findings and final diagnosis (11 correlated with surgical/histopathological findings, 12 corroborated on follow-up while 1 correlated with per-rectal/colonoscopy findings). MRI findings of only 3 out of 27 patients didn’t show correlation with final outcome.
Conclusion: MRI is indispensable for accurate local staging of carcinoma rectum which, in turn, decided further course of treatment.
Key Words: rectal carcinoma, MRI, anal sphincter, staging.
