Single- and multiparameter magnetic resonance imaging for diagnosing and severity grading of chronic pancreatitis.

Abstract

The study aimed to determine the performance of advanced magnetic resonance imaging (MRI), including a multiparametric MRI-index, for diagnosing and severity grading of chronic pancreatitis (CP) at various functional stages with focus on detection of CP with preserved pancreatic function. Fifty-four CP patients and 35 healthy controls underwent MRI including assessment of pancreatic volume, main pancreatic duct (MPD) diameter, T1 relaxation time, magnetic resonance elastography (MRE) derived stiffness, and intravoxel incoherent motion (IVIM) diffusion-weighted imaging. Patients were categorized into three subgroups: Preserved pancreatic function (n = 14), partial pancreatic insufficiency (exocrine insufficiency or diabetes, n = 25), and complete pancreatic insufficiency (exocrine insufficiency and diabetes, n = 15). A multiparametric MRI-index was based on ordinal logistic regression analysis. Diagnostic performances of MRI parameters for diagnosing CP at different functional stages were determined using receiver operating characteristic (ROC) analysis. All MRI parameters differed across CP subgroups and healthy controls (all P < 0.001), except for IVIM. T1 relaxation time (ROC area under the curve (ROC-AUC) 0.82), MRE (ROC-AUC 0.88), and MRI-index (ROC-AUC 0.86) showed the highest performance for detecting patients with preserved pancreatic function (early CP) vs. healthy controls. For detecting preserved pancreatic function vs. partial insufficiency, pancreatic volume, MRI-index, and T1 relaxation time performed best (all ROC-AUC > 0.75), with the MRI-index tending to outperform MRE (ROC-AUC 0.77 vs. 0.63; P = 0.10). Quantitative assessments of T1 relaxation time and MRE-derived stiffness seem promising for diagnosing CP at different functional stages and may together with multiparametric MRI-index be used for early identification, staging and monitoring of CP.