Nathan White1, Anders M. Dale2
1University of California, San Diego, La Jolla, CA, United States; 2Radiology and Neurosciences, University of California, San Diego, La Jolla, CA, United States
The apparent restricted water signal, derived from restriction spectrum imaging (RSI) data, provides improved conspicuity and delineation of high-grade brain tumors and reduced sensitivity to edema compared with traditional ADC. However, the biological origin of the restricted water signal remains poorly understood. In this study, we use Monte Carlo simulations to evaluate the specific role of the nuclear volume fraction and cell diameter on RSI signal contrast. The results suggest that the nuclear volume fraction is an important cellular characteristic for both RSI and ADC contrast, that may explain in part the lack of apparent restriction in low-grade tumors.