ABSTRACT
The study was conducted to evaluate the role of MDCT colonography in diagnosis of cob-rectal neoplasms compared to conventional colonoscopy. Fifty patients were included in the present study 28 males and 22 females with age ranged from 2 1-75 years old. Patients were presented with variable-size large bowel masses examined by MDCT colonography and conventional colonoscopy. Twenty three-cases were diagnosed by CT colonography as colonic malignancy, 18 cases diagnosed by colonoscopy as colorectal benign polyps "8 polyps measured less than 5mm, 6polyps from 5-10mm and 4 more than 10mm", those were correlated with findings of CT colonography which revealed only 12 benign polyps with size ranged from 6mm to more than 10 mm. The other 9 cases proved to be extra colonic metastases. MDCT colonography allows more definitive evaluation of the different cob-rectal and extra-colonic masses as it is anon-invasive modality. It has a higher sensitivity for detecting a clinically suspected colonic neoplastic mass. The conventional colonoscopy may still have an advantage of detecting very small and superficial mucosal lesions and taking biopsy from the suspected superficial areas