Evaluation of Malignant Predictive in Pancreatic Intraductal Papillary Mucinous Neoplasm Using Diffusion-weighted Imaging and Apparent Diffusion Coefficient Values: A Comparative Analysis With Histopathology.

Abstract

Objectives: Differentiating benign and malignant intraductal papillary mucinous neoplasms (IPMNs) can facilitate optimal clinical management. However, the current high-risk stigmata (HRS) criteria lack specificity. In this study, we aim to evaluate the diagnostic accuracy of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values, which are reported to improve diagnostic accuracy, for distinguishing benign and malignant IPMNs.

Materials and methods: This study included 50 patients who underwent pancreatic resection for IPMN or intraductal papillary mucinous carcinoma (IPMC) from 2013 to 2023. The benign group comprised intraductal papillary mucinous adenoma, whereas the malignant group included high-grade IPMN and invasive IPMC. Imaging findings were compared with histopathologic results. ADC values were measured using regions of interest (ROIs) on DWI, with 800 s/mm2 b-value. The optimal ADC cutoff value for malignancy prediction was determined by operating characteristic curve analysis.

Results: Diagnostic accuracy of DWI was 85%, outperforming HRS at 64%. The malignant group had significantly lower minimum ADC values in ROIs than the benign group (1780 vs 1,181 mm2/s, P < 0.01). The mean ADC in 2438 mm2/s ROI cutoff value yielded 79% sensitivity, 79% specificity, and 0.761 area under the curve. In addition, the malignant group had significantly large mural nodules and low ADC values (r = -0.43842, P = 0.0033).

Conclusions: DWI and ADC mapping are valuable diagnostic tools for differentiating benign and malignant IPMNs. These modalities can complement existing diagnostic criteria, reduce unnecessary surgeries, and enhance clinical decision-making.