ROLE OF MAGNETIC RESONANCE IMAGING IN LOCAL STAGING OF RECTAL CANCER

Abstract

Rectal cancer is one of the most common causes of cancer cases all over the world. Its highest incidence is found in industrialized developed countries and its lowest incidence is found in developing countries. Our study included 20 patients with preoperatively diagnosed rectal cancer and the mean age was 48.05 (ranges from 26 to 74 years). All patients have been subjected to pelvic MRI assessment performed on 1.5T magnet with pelvic phased array coil and rectal gel administration. The MRI protocol was T1W in axial plane, T2W in axial, coronal and sagittal planes, T1W postcontrast fat saturation in axial, coronal and sagittal planes and DW-MRI. All cases have undergone surgery and their specimens were sent for histopathological assessment. We found that the MRI results of 19 out of 20 patients were correct when compared with the histopathological results in different T stages (i.e. accuracy was 95%). Regarding the differentiation of T2/T3 tumors, the sensitivity, specificity, PPV, NPV and accuracy were 85.70%, 100%, 100%, 85.70% and 92.30%, respectively. Regarding the differentiation of T3/T4 tumors, the sensitivity, specificity, PPV, NPV and accuracy were 100%, 100%, 100%, 100% and 100%, respectively. Regarding N staging, we found that the MRI results of 18 out of 20 patients were correct when compared with histopathological results in different N stages (i.e. accuracy was 90%). In the evaluation of mesorectal fat invasion in comparison with histopathological examination, we found that the MRI accuracy was 100%. In the evaluation of MRF invasion in comparison with histopathological examination results, we found that the MRI accuracy was 100%. In the evaluation of the CRM status in comparison with histopathological examination results, we found that the values of sensitivity, specificity, PPV, NPV and accuracy were 100%, 100%, 100%, 100% and 100%, respectively.