IVIM and Non-Gaussian DWI of the Breast

Intravoxel incoherent motion (IVIM) and non-Gaussian analysis of diffusion-weighted imaging (DWI) data can provide detailed information on tissue microstructure and microvasculature beyond that measured by apparent diffusion coefficient (ADC). In terms of signal intensity on DWI, the attenuation in vivo is not monoexponential at low b values (≤200 s/mm2) or high b values (at least ≥1000–1500 s/mm2). The DWI signal at low b values is sensitive to blood microcirculation (IVIM) in vivo, and the deviation of the signal from Gaussian diffusion at high b values is termed a non-Gaussian DWI effect and relates to tissue microstructural complexity. Due to the limitations of the monoexponential model (ADC), several studies investigated IVIM and non-Gaussian DWI models and their utility in breast cancer diagnosis. The chapter will review the current status of applications of IVIM and non-Gaussian DWI of the breast. Acquisition protocols for IVIM and non-Gaussian diffusion will be presented, as well as processing approaches, separately or for IVIM and non-Gaussian DWI in combination.