Influence of Diffusion Time and Gradient Strength on the Estimation of Cell Size in MRI Cytometry

Motivation: To investigate the influence of diffusion time and gradient strength on the estimation of cell size in tumors in MRI cytometry. Goal(s): To find optimal diffusion time range and gradient strength to estimate tumor cell size. Approach: Two animal tumor models (B16 and MC38) were used. Cell size (d) was estimated utilizing VERDICT, IMPULSED and OGSE only methods at maximum gradient strengths. MRI-derived cell size was compared with histology ground truth. Results: VERDICT overestimated cell size compared to IMPULSED and OGSE only methods at gradient strength 65mT/m. Accuracy of cell size estimation increases with gradient strength but should cover broad diffusion time range. Impact: OGSE only and IMPULSED derived mean cell size were comparable at all gradient strengths while VERDICT overestimated the mean cell size at 65mT/m suggesting to include OGSE in estimating tumor cell size.