Intravoxel incoherent motion diffusion-weighted imaging of the pancreas: Characterization of benign and malignant pancreatic pathologies

J Magn Reson Imaging. 2017 Jan;45(1):260-269. doi: 10.1002/jmri.25334. Epub 2016 Jun 7.

Abstract

Purpose: To evaluate the diagnostic value of apparent diffusion coefficient (ADC) and intravoxel incoherent motion (IVIM) parameters in differentiating patients with either a normal pancreas (NP), pancreatic ductal adenocarcinoma (PDAC), neuroendocrine tumor (NET), solid pseudopapillary tumor (SPT), acute pancreatitis (AcP), vs. autoimmune pancreatitis (AIP).

Materials and methods: In all, 84 pathologically confirmed pancreatic tumors (60 PDACs, 15 NETs, 9 SPTs), 20 pancreatitis (13 AcPs, 7 AIPs), and 30 NP subjects underwent IVIM diffusion-weighted imaging using 10 b-values (0-900 sec/mm2 ) at 1.5T. The ADC, pure molecular diffusion coefficient (Dslow ), perfusion fraction (f), and perfusion-related diffusion coefficient (Dfast ) were calculated and compared using a Kruskal-Wallis test and post-hoc Dunn procedure. Receiver operating characteristic (ROC) analysis was performed to assess diagnostic performance.

Results: The f and Dfast of the PDAC were significantly lower than that of the NP (f = 0.10 vs. 0.24; Dfast = 42.21 vs. 71.74 × 10-3 mm2 /sec; P < 0.05). In ROC analysis, f showed the best diagnostic performance (area-under-the-curve, 0.919) among all parameters in differentiating PDAC from NP (P ≤ 0.001). The f values of AcP (0.11) and AIP (0.13) and the Dfast values of SPT (20.48 × 10-3 mm2 /sec) and AcP (24.49 × 10-3 mm2 /sec) were significantly lower compared with NP (f = 0.24; Dfast = 71.74 × 10-3 mm2 /sec; P < 0.05). For NET, the f (0.21) was significantly higher than that of PDAC (0.10, P < 0.01).

Conclusion: Perfusion-related parameters f and Dfast are more helpful in characterizing pancreatic diseases than ADC or Dslow . The PDCA, SPT, AcP, and AIP were characterized by reduced f and Dfast values compared with normal pancreas. The f value might help in differentiating between PDAC and NET.

Level of evidence: 3 J. Magn. Reson. Imaging 2017;45:260-269.

Keywords: diffusion-weighted imaging; intravoxel incoherent motion; pancreas; pancreatic neoplasm; pancreatitis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Diagnosis, Differential
  • Diffusion Magnetic Resonance Imaging / methods*
  • Female
  • Humans
  • Image Enhancement / methods
  • Image Interpretation, Computer-Assisted / methods*
  • Imaging, Three-Dimensional / methods*
  • Male
  • Middle Aged
  • Motion
  • Pancreas / diagnostic imaging*
  • Pancreas / pathology
  • Pancreatic Neoplasms / diagnostic imaging*
  • Pancreatic Neoplasms / pathology
  • Pancreatitis / diagnostic imaging*
  • Pancreatitis / pathology
  • Reproducibility of Results
  • Sensitivity and Specificity