Prospective evaluation of pancreatic tumors: accuracy of MR imaging with MR cholangiopancreatography and MR angiography

PURPOSE: To prospectively assess accuracy of magnetic resonance (MR) imaging, MR cholangiopancreatography (MRCP), and MR angiography in patients suspected of having pancreatic tumors. MATERIALS AND METHODS: Sixty-six patients suspected of having pancreatic tumors underwent MR imaging (unenhanced and contrast material-enhanced MR, MRCP, and contrast-enhanced MR angiography). Two blinded readers prospectively analyzed the images by consensus, and results were correlated with surgery, biopsy, or follow-up findings. Results were tabulated in two-by-two tables. RESULTS: MR assessment of pancreatic lesion status (differentiation of benign vs malignant) resulted in 60 correct diagnoses (accuracy, 91%), and six (10%) false diagnoses. Among histologically proved malignant tumors, MR imaging yielded correct diagnoses in 42 of 44 patients (sensitivity, 95%; 95% CI: 85%, 99%), whereas 18 of 22 patients with benign findings were classified correctly. At MR imaging, findings in four patients with chronic pancreatitis were wrongly categorized as malignant tumors (specificity, 82%; 95% CI: 60%, 95%), and in one patient, a distal common bile duct carcinoma was not detected. In no patient with pancreatic adenocarcinoma was this tumor misdiagnosed as benign. In patients with malignant tumors who underwent resection, local-regional tumor growth and vascular infiltration were accurately classified in 89% and 94%, respectively. MR imaging depicted histologically proved synchronous hepatic metastases in 82%. The positive and negative predictive values for cancer nonresectability were 90% and 83%, respectively, and the accuracy, sensitivity, and specificity were 85%, 69%, and 95%, respectively. CONCLUSION: Unenhanced and contrast-enhanced MR imaging with MRCP and MR angiography offers potential as a noninvasive tool for assessment of patients suspected of having pancreatic tumors.