Gradient performance-constrained optimization of OGSE time-dependent diffusion MRI for tissue microstructure imaging

Motivation: OGSE diffusion MRI (OGSE-dMRI) has been shown to differentiate tumor cellular density and thus improve tumor grading and post-treatment evaluation. Imaging protocol to maximize the differentiation is desired. Goal(s): A framework to optimize OGSE-dMRI protocol. Approach: Maximum b-values at different OGSE frequencies and echo times were generated based on gradient performance. ADC(f)/ADC(0 Hz) estimated from a tumor signal model was calculated. Receiver operating characteristic of differentiating cellular density was analyzed and the optimized protocol was obtained at maximum area-under-the-curve. Results: Higher area-under-the-curve was achieved at high OGSE frequency, high b-value, and short echo time using high-performance gradient MRI system. Impact: Radiologists, MR physicists, and engineers who need optimized imaging protocol of OGSE time-dependent diffusion MRI to assess tumor microstructure and improve clinical diagnosis of tumor grading and evaluation of treatment effectiveness.