Motivation: Fat signal suppression is essential for breast DWI as the very low diffusion coefficient of fat tends to decrease ADC values. STIR is a popular method, but signal suppression/attenuation is not specific to fat. Goal(s): To show how ADC values obtained with STIR DWI may be biased toward tissue components with long T1s. Approach: Results were obtained from simulations and data acquired in a dedicated breast DWI phantom made of vials with water and various concentration of PVP. Results: ADC values obtained with STIR fat suppression may be over/under estimated depending on the T1 and ADC profile within tissues. Impact: Fat suppression is essential for DWI. Among techniques STIR leads to low SNR and ADC misestimation depending on the tissues T1/ADC content, as STIR signal attenuation is not specific to fat. Other methods should be preferred, such as SPAIR.

Effect of tissues T1 content on the ADC values obtained with breast DWI using STIR fat-suppression