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Background The aim of this retrospective study was to highlight the role of adding DWI to the conventional MRCP in differentiating benign and malignant obstructive biliary pathologies. MRCP is a non-invasive modality for investigating the morphological features of the pancreaticobiliary system. It can provide indirect evidence of a malignant lesion, such as irregularity of the inner border and abrupt stenosis, with shouldering of the edge suggesting cholangiocarcinoma, while a short segment with regular margin and symmetric narrowing suggests a benign cause. Although these findings are highly sensitive, they are not specific. DWI can complement morphological information obtained by conventional MRCP by providing additional functional information concerning the alteration of tissue cellularity due to pathological processes. Results The overall accuracy of the diagnosis, sensitivity, and specificity of the conventional MRCP in differentiation between the benign and malignant biliary structures was significantly increased by combing it with the DWI. Conclusions Adding DWI to conventional MRCP significantly improved the diagnostic accuracy regarding the characterization of differentiating benign and malignant biliary strictures.

Background: Multidetector CT is the mainstay for radiologic evaluation of pancreatic pathology. Still, imaging of focal pancreatic lesions using MDCT is faced by a number of challenges that are related to the limited contrast between the lesion and surrounding parenchyma, such as detecting early-stage pancreatic cancer and subtle features of cystic lesions that point to malignancy. Dual-layer CT is the first dual-energy CT machine based on separation of high-and low-energy photons at the detector level. If improved contrast between the lesions and normal pancreatic parenchyma could be achieved on CT images, we may expect enhanced CT detection of pancreatic lesions. The purpose of this study was to evaluate whether virtual monoenergetic reconstructions generated using contrast-enhanced dual-layer CT could improve detectability of hypoattenuating focal pancreatic lesions compared to conventional polyenergetic reconstructions. Results: Fifty-four lesions were identified and verified by histopathology or follow-up CT, MRCP, and/or EUS along with clinical data. Across the virtual monoenergetic spectrum, 40 KeV images had the highest contrast-to-noise and signal-to-noise ratios (p < 0.001, p < 0.001) and were significantly higher than conventional images (p < 0.001). Subjective scores for lesion visibility at low kiloelectron volt monoenergetic (40 and 50 KeV) images greatly exceeded conventional images (p < 0.001). Conclusion: Low kiloelectron volt monoenergetic reconstructions of contrast-enhanced dual-layer CT significantly improve detectability of hypoattenuating focal pancreatic lesions compared to conventional polyenergetic reconstructions.