EUS versus magnetic resonance imaging for the diagnosis of focal pancreatic lesion in patients with chronic pancreatitis

Background and Objectives: Distinguishing pancreatic cancer from inflammatory conditions in patients with chronic pancreatitis (CP) is challenging. Contrast-enhanced magnetic resonance imaging (MRI) and EUS are key diagnostic modalities, but their optimal use (alone or in combination) for accurate diagnosis remains unclear. This study aimed to compare the diagnostic efficacy of EUS and contrast-enhanced MRI for focal pancreatic lesions in CP patients. Methods: This single-center retrospective study enrolled CP patients with indeterminate focal pancreatic lesions detected by contrast-enhanced computed tomography. Patients underwent contrast-enhanced MRI, EUS, or both, and were categorized into 3 groups: MRI group, EUS group, and Combination group. Primary diagnoses were based on the reports of imaging or EUS-guided tissue acquisition, while final diagnoses were confirmed by surgical pathology or follow-up. The primary outcome was diagnostic performance. Results: A total of 103 patients were enrolled: 48 in the MRI group, 10 in the EUS group, and 45 in the Combination group. There were no statistically significant differences in diagnostic performance between these 2 independent groups. However, in the paired subgroup analysis, EUS demonstrated significantly higher accuracy than MRI (84.4% vs. 68.9%, P = 0.039). Further comparison revealed no significant difference in sensitivity (50.0% vs. 64.3%, P = 0.500), specificity (100.0% vs. 83.9%, P = 0.063), and accuracy (84.4% vs. 77.8%, P = 0.453) between EUS and the combination diagnosis. Conclusion: EUS was a superior individual diagnostic modality to MRI for evaluating focal pancreatic lesions in CP patients, and MRI did not provide significant additional diagnostic benefit over EUS alone.