Can abbreviated MRI replace standard protocols in IPMN surveillance? A retrospective comparative study

With the advancements in imaging technologies and the widespread use of magnetic resonance imaging (MRI), the detection rates of pancreatic cystic lesions (PCLs) have significantly increased. While most of these lesions are benign, branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) pose a potential risk for malignant transformation, necessitating regular clinical and radiological follow-up. However, conventional MRI protocols are time-consuming and resource-intensive, prompting the need for shorter, cost-effective alternatives without compromising diagnostic accuracy. This study aims to evaluate the diagnostic performance and clinical feasibility of abbreviated MRI (A-MRI) protocols for BD-IPMN surveillance compared to standard MRI (S-MRI).

This was a single-center, retrospective study including patients with BD-IPMN who underwent follow-up MRI between January 2022 and December 2024. Three MRI protocols were analyzed: (1) S-MRI, comprising T2-weighted imaging, dynamic contrast-enhanced (DCE) T1-weighted imaging, 3D MR cholangiopancreatography (MRCP), and diffusion-weighted imaging (DWI); (2) A-MRI protocol 1 (A-MRI-1), including MRCP and T2-weighted sequences; and (3) A-MRI protocol 2 (A-MRI-2), incorporating MRCP, T2-weighted, and DWI sequences. The images were evaluated for lesion size progression (≥ 5 mm in 2 years), mural nodules, cyst wall thickening, main pancreatic duct dilation, and parenchymal atrophy. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for A-MRI protocols in detecting degeneration signs.

A total of 124 patients (mean age: 64 years, 55.6% female) and 124 lesions were analyzed. The detection rates of key degeneration markers were similar between S-MRI and A-MRI protocols, except for contrast-enhanced mural nodules, which were not identifiable with A-MRI due to the lack of DCE sequences. The overall sensitivity, specificity, PPV, and NPV for A-MRI in detecting BD-IPMN degeneration markers were 100%, 98.3%, 71.4%, and 100%, respectively. A-MRI protocols demonstrated a comparable diagnostic performance to S-MRI while significantly reducing scan time (from ~ 40-50 min to 7-12 min). However, false-positive mural nodule detection was higher with A-MRI, potentially leading to unnecessary follow-up imaging. The addition of DWI in A-MRI-2 did not provide a significant diagnostic advantage over A-MRI-1.

A-MRI is a viable alternative for BD-IPMN follow-up, offering substantial reductions in imaging duration and costs while maintaining high diagnostic accuracy. However, the absence of DCE sequences may lead to false-positive mural nodule detection, necessitating further evaluation in selected cases.