Published online Oct 28, 2015. doi: 10.4329/wjr.v7.i10.319
Peer-review started: January 28, 2015
First decision: April 14, 2015
Revised: April 27, 2015
Accepted: August 25, 2015
Article in press: August 28, 2015
Published online: October 28, 2015
Processing time: 271 Days and 6.8 Hours
Magnetic resonance imaging (MRI) is a reliable and accurate imaging method for the evaluation of patients with pancreatic ductal adenocarcinoma (PDAC). Diffusion-weighted imaging (DWI) is a relatively recent technological improvement that expanded MRI capabilities, having brought functional aspects into conventional morphologic MRI evaluation. DWI can depict the random diffusion of water molecules within tissues (the so-called Brownian motions). Modifications of water diffusion induced by different factors acting on the extracellular and intracellular spaces, as increased cell density, edema, fibrosis, or altered functionality of cell membranes, can be detected using this MR sequence. The intravoxel incoherent motion (IVIM) model is an advanced DWI technique that consent a separate quantitative evaluation of all the microscopic random motions that contribute to DWI, which are essentially represented by molecular diffusion and blood microcirculation (perfusion). Technological improvements have made possible the routine use of DWI during abdominal MRI study. Several authors have reported that the addition of DWI sequence can be of value for the evaluation of patients with PDAC, especially improving the staging; nevertheless, it is still unclear whether and how DWI could be helpful for identification, characterization, prognostic stratification and follow-up during treatment. The aim of this paper is to review up-to-date literature data regarding the applications of DWI and IVIM to PDACs.
Core tip: Diffusion-weighted imaging (DWI) plays an important role for the identification of pancreatic adenocarcinoma, even if small in size, thus allowing early diagnosis. The intravoxel incoherent motion model is a promising DWI technique for the characterization of this tumor, with potential usefulness for the differentiation from mass-forming pancreatitis. Thanks to its high negative prognostic value, DWI should be used to assess the presence of liver metastases in patients with pancreatic adenocarcinoma.