Added value of Diffusion Weighted Imaging (DWI) and Magnetic Resonance Cholangiopancreatography (MRCP) to Computed Tomography (CT) in differentiating benign and malignant biliary tree strictures

Background Biliary strictures represent a major diagnostic challenge owing to the broad overlap between benign inflammatory conditions and malignant obstructive lesions. Accurate preoperative characterization is essential to guide management decisions, prevent unnecessary invasive interventions, and optimize patient outcomes. Although multidetector computed tomography (MDCT) remains a widely available first-line imaging modality, its specificity in distinguishing benign from malignant strictures is limited. Magnetic resonance cholangiopancreatography (MRCP) and diffusion-weighted imaging (DWI) provide complementary anatomical and functional information and have the potential to significantly improve diagnostic performance. Objective To determine the added diagnostic value of MRCP and DWI when combined with MDCT for differentiating benign from malignant biliary strictures, using histopathology as the reference standard. Methods This prospective study included patients presenting with biliary obstruction who underwent MDCT followed by MRCP and DWI prior to obtaining histopathological confirmation. Imaging features, including stricture morphology, length, wall characteristics, and apparent diffusion coefficient (ADC) values, were systematically evaluated. Diagnostic accuracy metrics—sensitivity, specificity, and overall accuracy—were compared between MDCT alone and the combined CT–MRCP–DWI approach. Results Malignant strictures were characterized by significantly lower ADC values and greater morphological irregularity compared with benign strictures. MDCT alone demonstrated moderate accuracy in differentiating stricture etiology, whereas the addition of MRCP and DWI substantially improved diagnostic performance, increasing sensitivity, specificity, and overall accuracy. The combined protocol provided superior delineation of the level and extent of biliary involvement and enhanced confidence in determining the underlying cause of obstruction. Conclusion The integration of MRCP and DWI with MDCT markedly improves the diagnostic accuracy for differentiating benign from malignant biliary strictures. This multiparametric imaging strategy enhances anatomical visualization, adds functional tissue characterization, and should be incorporated into routine assessment of indeterminate biliary strictures to support optimal clinical decision-making.