To reveal the adding value of diffusionweighted Magnetic Resonance Imaging (MRI) in the detection and differential diagnosis of the colorectal cancer, comparing the results of Apparent Diffusion Coefficient (ADC) value with histopathological studies. Aim of Study: The aim of the study was to determine the effectiveness of MRI in the diagnosis of colorectal cancers and to reveal the adding value of DWI in the detection and differential diagnosis of the colorectal cancer, comparing the results of

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... ADC value with histopathological studies. Material and Methods: Fifteen patients with suspected colorectal cancers clinically, endoscopically or by CT and US images were included in this study. All cases have been evaluated with 1.5 MR scanner. In addition to the conventional sequences (T2-axial, sagittal and coronal weighted images (WI), axial T2 STIR, T1 WI and a Diffusion-Weighted Images (DWI) with 4 different b-values (0, 400, 600 and 1000s/mm 2 and ADC maps were obtained then the results have been compared to histopathological diagnosis. Results : All cases of malignant colorectal cancer showed high signal (restricted diffusion) on DWI. Receiver Operating Curve (ROC) analysis of ADC values yielded an Area Under Curve (AUC) of 0.912, setting a threshold ADC value of <1.1 X 10 -3 mm 2 /sec yielded a sensitivity of 82.8% and specificity of 100% in detecting the malignant colorectal masses. Conclusion: DWI with high b-values and ADC value is a feasible method and has the potential to be effective in detection of colorectal cancer.