Diffusion-Weighted Magnetic Resonance Imaging Attenuation Factors and Their Selection for Cancer Diagnosis and Monitoring.

Diffusion-weighted imaging (DWI) is based on the detection of water molecule movement in interstitial and intracellular space, and that motion may be restricted in ischemia and in tumors. An early diagnosis and characterization of several cancer related diseases is possible with DWI. Diffusion-weighted images are therefore important for patient management. Knowledge of the technical requirements for DWI, including a suitable selection of b-values for differentiating between perfusion and true diffusion, as well as an understanding of the advantages and limitations of different b-values selections, is necessary to obtain reliable diagnostic results. The aim of this article is to review the fundamentals of the DWI technique, the common protocols used, b-value selection, and DWI's main contribution to neoplasm detection and staging.