Added Value of Diffusion-Weighted Imaging to MRCP in Differentiating Benign from Malignant Biliary Strictures

Background: Differentiating benign from malignant obstructive biliary disorders remains challenging. Magnetic Resonance Cholangiopancreatography (MRCP) is considered the investigation of choice to assess the pancreatobiliary system. This research aimed to evaluate the possible role of adding DWI to MRCP to increase the accuracy of differentiation between benign and malignant obstructive biliary lesions. Methods: We carried out this prospective cross-sectional study on 24 patients who have been enrolled for MRCP evaluation of their biliary tree as they complained of obstructive jaundice with no definite diagnosis by prior investigations. All examinations were performed using a 1.5-T MR scanner with a phased-array body coil. The imaging protocol included conventional sequences and MRCP, followed by diffusion-weighted imaging (DWI). Stricture morphology, signal intensity, as well as diffusion restriction were evaluated, with final diagnosis confirmed by histopathology obtained by ERCP and follow up. Results: Among 24 patients , 13 patients (54.2%) had benign strictures while 11 (45.8%) had malignant strictures. Combining DWI and MRCP enhanced the diagnostic accuracy dramatically by adding functional information to the morphological features of the stricture. MRCP alone showed 75% sensitivity and 75% specificity, DWI demonstrated 81.8% sensitivity and 100% specificity, while the combined MRCP–DWI approach provided the strongest statistical significance (p < 0.001), achieved 90.9% sensitivity, 100% specificity, and an overall accuracy of 95.8%. Conclusion: Combining DWI with MRCP markedly improves the differentiation of benign and malignant biliary strictures compared with either modality alone