Evidence of Background-Gradient Effects in GRE-based 3He Diffusion MRI
Mugler III J, Mata J, Altes T, Miller G, Brookeman J, de Lange E, Tobias W, Cates Jr. G
University of Virginia
Since 3He diffusion MRI commonly uses GRE-based methods, and because the lung by nature contains countless air-tissue interfaces, which lead to a very inhomogeneous magnetic environment, it is reasonable to expect that susceptibility-induced background gradients may influence 3He ADC measurements. For GRE-based diffusion acquisitions that use a pair of bipolar gradient waveforms with an intervening time delay for diffusion sensitization, we observed an increase in the measured ADC with an increase in the time delay and, in a subject with COPD that exhibited a wide range of ADC values, we observed that this increase is inversely correlated with ADC value.