Is the breast ADC category system a useful addition to BI-RADS?

Excerpt

Diffusion-weighted imaging (DWI) is a non-invasive imaging technique that can provide information about tissue microstructure and function through visualization of the diffusion displacement of water molecules in biological tissues. DWI was first introduced in brain imaging in the mid-1980s and is now a mainstay of cancer imaging throughout the body, including the breast. Many papers have shown that malignant tumors exhibit lower apparent diffusion coefficient (ADC) values (enhanced signal intensity on DWI) than benign lesions, mainly because of increased cellularity [1]. By providing both qualitative and quantitative information, DWI can aid in the diagnosis and characterization of breast lesions and the monitoring of response to therapy. Several models have been devised for quantitative evaluation, with the ADC being the simplest yet most robust marker. The ADC is derived from an approximate calculation of the diffusion signal assuming that the diffusion signal decays linearly (in a log plot). Since the ADC can be calculated from only two b-values (which quantify the degree of diffusion weighting in the images), it is easy to calculate, and it takes only a few minutes to acquire the necessary images. The ADC has become widely used in the evaluation of breast lesions, along with dynamic contrast-enhanced MRI. Numerous studies have shown the utility of ADC values for differentiating malignant breast lesions from benign lesions or normal breast tissue, and for classifying breast cancer [1]. …