Magnetic resonance measurement of diffusion in the abdomen.

Diffusion-weighted (DW) magnetic resonance imaging is an emerging noninvasive technique increasing its spectrum of use in the abdomen. Diffusion-weighted imaging has been used as add-on to routine abdominal protocol because it may potentially substitute contrast-enhanced imaging in cases under risk of nephrogenic systemic fibrosis. The apparent diffusion coefficient (ADC) images calculated from DW images enable qualitative and quantitative evaluations of tissue water mobility and functional environment because of changes in intracellular, extracellular, and intravascular tissue compartments. This article presents the basic physics of the ADC measurement, the techniques for performing ADC measurements of the liver and the pancreas, and the clinical applications of DW imaging.