DWI findings of autoimmune pancreatitis: comparison between symptomatic and asymptomatic patients

Area of Science:

• Radiology
• Gastroenterology
• Medical Imaging

Background:

• Autoimmune pancreatitis (AIP) is a chronic inflammatory condition requiring timely diagnosis and treatment.
• Differentiating symptomatic from asymptomatic AIP is crucial for initiating steroid therapy.
• Current diagnostic methods may not always provide objective markers for symptom severity.

Purpose of the Study:

• To compare magnetic resonance imaging (MRI) findings, including diffusion-weighted imaging (DWI), between symptomatic and asymptomatic AIP patients.
• To evaluate the potential of DWI as an objective biomarker for identifying symptomatic AIP, indicating the need for steroid therapy.

Main Methods:

• Retrospective analysis of MRI scans from 37 AIP patients (19 symptomatic, 18 asymptomatic).
• Assessment of specific MRI features including parenchymal enlargement, main pancreatic duct narrowing, T1WI hypointensity, capsule-like rim, extrapancreatic lesions, and DWI hyperintensity.
• Comparison of findings using logistic regression and calculation of apparent diffusion coefficient (ADC) values.

Main Results:

• Hyperintensity on DWI was significantly associated with AIP symptoms (odds ratio = 28.2, P = 0.003).
• ADC values were significantly lower in symptomatic AIP patients compared to asymptomatic ones (0.94 ± 0.17 vs. 1.16 ± 0.16 × 10⁻³ mm²/s, P < 0.001).
• Receiver operating characteristic analysis for ADC values showed 68.4% sensitivity, 83.3% specificity, and an AUC of 0.74 for differentiating symptomatic from asymptomatic AIP.

Conclusions:

• Diffusion-weighted imaging (DWI) signal intensity and ADC values correlate well with active AIP symptoms.
• DWI shows promise as an objective biomarker for determining the indication for steroid therapy in AIP patients.