Ultrasound Evaluation of Colorectal Malignancy with Contrast Enhanced Computed Tomography as Gold Standard

Background and objectives Colorectal carcinoma is one of the most common consequential cause of death from cancer in the west and is the 6th most common cause of cancer deaths India. These tumors can enlarge with time and then invade the colon consummately. Early detection and treatment is critical. Computed tomographic (CT) is a non-invasive and rapidly evolving investigation that is a potential alternative to conventional flexible colonoscopy for colorectal malignancy screening. However, the lack of CT equipment in the lesser developed places mandates the use of ultrasound for detection of the disease. Prevention and early detection are key factors in controlling and curing colorectal cancer. Indeed, colorectal cancer is the second most preventable cancer, after lung cancer. When the cancer is found early, initial treatment can often lead to an excellent outcome. Today, the average person has about a 1 in 20 chance of developing colorectal cancer during his or her life. Therefore the need to study the usefulness and accuracy of ultrasound (USG) scan in detecting colorectal lesion at the earliest is necessary and validated. Materials and methods Thirty one patients with colorectal malignancies were studied. They were included in the study if they met the inclusion and exclusion criteria. The sex ratio, age distribution was noted, tabulated and charted Results Of the 31 cases with colorectal malignancy studied, it was observed that males aremore commonly affected by colorectal malignancies than women with a ratio of 21. It most commonly affects people in 4th to 6th decade of life. CECT showed most patients presented with irregular heterogeneously enhancingcircumferential wall thickening of the involved bowel (96.8 %), sometimes associatedwith mass (19.4 %). Most of these patients presented with pain abdomen, bleedingper rectum with or without constipation. Ultrasound abdomen shows high sensitivity (87.1 %) in detecting colon wallpathology however, the lesion is the rectum alone, were frequently missed (58 %). Besides, involvement of adjacent viscera was identified by USG in 84 %. USGevaluation of metastatic secondaries had limited results (limitation for pulmonarymetastasis) and therefore staging of themalignancy with ultrasound was found inaccurate. Conclusion Ultrasound of abdomen shows high sensitivity in detecting large bowel malignancies except for lesions involving the rectum. If coupled with transrectal ultrasound or rectosigmoidoscopy, can be very effective tool for screening purposes as it displays high sensitivity and specificity. In low volume centres where CT is not available or not affordable by the patient, USG abdomen coupled with trans-rectal ultrasound (TRUS) can be considered as modality of choice for screening purposes. However, once a lesion is detected, CECT plays a major role in staging and further management.