ACCURACY OF COMPUTED TOMOGRAPHY IN CHARACTERISATION OF COLORECTAL LESIONS AS BENIGN OR MALIGNANT AND IN PRE-OP STAGING OF COLORECTAL CARCINOMA WITH HISTOPATHOLOGICAL CORRELATION

Objective-To determine the accuracy of Multi Detector CT in characterizing colorectal lesions as benign or malignant - and its correlation with histopathology by studying bowel wall characteristics. - Methods 55 patients referred to the Department of Radiodiagnosis at a tertiary care centre in Trivandrum for contrast CT abdomen who had abnormal bowel wall thickening on CT. Lesions are classied on CT as benign or malignant based on bowel wall characteristics of wall thickening and staging is done in case of colorectal carcinoma. The ndings are then compared with the histopathological diagnosis. Results- Overall, CT had a sensitivity of 94.9%, specicity of 93.8%, Positive Predictive Value of 97.4% and a Negative Predictive Value of 88.2% in the diagnosis of malignant lesions. Accuracy of CT in diagnosing malignant lesions is 94.5%. Positive likelihood ratio is 15.2. and negative likelihood ratio is 0.05.CT is an excellent modality for tumour (T) staging in colorectal malignancy, as per our study, K=0.806 (excellent agreement).CT, though not highly accurate, can be used for lymph nodal (N) staging in colorectal malignancy, as per our study, K= 0.213 (fair agreement). Conclusion- Due to its high sensitivity and specicity, MDCT is an excellent modality in the diagnosis and differentiation of benign and malignant lesions of the colon and rectum,.It offers early detection of colorectal malignancy, provides staging of malignancies, helps in detection of metastasis, thereby aiding in the choice of treatment strategy. CT is an excellent modality for tumour (T) staging in colorectal malignancy, as per our study, K=0.806 (excellent agreement).