Diffusion-Weighted Magnetic Resonance Imaging of the Pancreas Diagnostic Benefit From an Intravoxel Incoherent Motion Model-Based 3 b-Value Analysis

Objectives The objective of this study was to evaluate the diagnostic benefit of an intravoxel incoherent motion (IVIM) model-based characterization of pancreatic masses from diffusion-weighted imaging (DWI) with 3 b values. Materials and Methods This retrospective study had an approval from the institutional review board, and informed patient consent was waived. The 1.5-T DWI data of 42 patients with or without pancreatic disease, acquired by a respiratory-gated spin-echo echo-planar imaging sequence with 3 b values (0, 50, 800 s/mm(2)), were retrospectively analyzed. The IVIM-related parameters D, which is the apparent diffusion coefficient [ADC(50,800)], and f, as well as ADC(0,50), and conventional ADC(0,800) were calculated voxelwise. Regions of interest were analyzed in pancreatic adenocarcinomas (CAs, n = 12), neuroendocrine pancreatic tumors (NETs, n = 9), and chronic pancreatitis (CPs, n = 11), not affected tissue of each pathologic group, and in the head, body, and tail of the healthy pancreas (n = 10). Results By ADC(0,800) and D, CAs could hardly be distinguished from neuroendocrine pancreatic tumors and chronic pancreatitis. However, CAs revealed very low ADC(0,50) and f values, which differed significantly from all other groups. In the healthy pancreas, ADC(0,800) and D values were significantly higher for the head than for the body and tail, but no significant differences were found for ADC(0,50) and f. Conclusions The determination of IVIM-based microcirculation-sensitive parameter maps from DWI with 3 b values significantly improved the discrimination of CAs from NETs, CPs, and the healthy tissue.