Optimal acquisition scheme for flow‐compensated intravoxel incoherent motion diffusion‐weighted imaging in the abdomen: An accurate and precise clinically feasible protocol

PURPOSE: Flow‐compensated (FC) diffusion‐weighted MRI (DWI) for intravoxel‐incoherent motion (IVIM) modeling allows for a more detailed description of tissue microvasculature than conventional IVIM. The long acquisition time of current FC‐IVIM protocols, however, has prohibited clinical application. Therefore, we developed an optimized abdominal FC‐IVIM acquisition with a clinically feasible scan time. METHODS: Precision and accuracy of the FC‐IVIM parameters were assessed by fitting the FC‐IVIM model to signal decay curves, simulated for different acquisition schemes. Diffusion‐weighted acquisitions were added subsequently to the protocol, where we chose the combination of b‐value, diffusion time and gradient profile (FC or bipolar) that resulted in the largest improvement to its accuracy and precision. The resulting two optimized FC‐IVIM protocols with 25 and 50 acquisitions (FC‐IVIM(opt25) and FC‐IVIM(opt50)), together with a complementary acquisition consisting of 50 diffusion‐weighting (FC‐IVIM(comp)), were acquired in repeated abdominal free‐breathing FC‐IVIM imaging of seven healthy volunteers. Intersession and intrasession within‐subject coefficient of variation of the FC‐IVIM parameters were compared for the liver, spleen, and kidneys. RESULTS: Simulations showed that the performance of FC‐IVIM improved in tissue with larger perfusion fraction and signal‐to‐noise ratio. The scan time of the FC‐IVIM(opt25) and FC‐IVIM(opt50) protocols were 8 and 16 min. The best in vivo performance was seen in FC‐IVIM(opt50). The intersession within‐subject coefficients of variation of FC‐IVIM(opt50) were 11.6%, 16.3%, 65.5%, and 36.0% for FC‐IVIM model parameters diffusivity, perfusion fraction, characteristic time and blood flow velocity, respectively. CONCLUSIONS: We have optimized the FC‐IVIM protocol, allowing for clinically feasible scan times (8‐16 min).