Stimulated echo induced misestimate on diffusion tensor indices and its remedies
Chuang T, Huang T, Lin Y, Chung H, Wu M, Ko C, Tsai S, Chao T
National Taiwan University
The dual spin-echo technique with twice-refocused gradient provides diffusion tensor images (DTI) immune to eddy-current effects. The resulting estimates of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA), however, were found to be inconsistent with values obtained from conventional DTI. In this work we showed that the measurement errors could originate from the formation of stimulated echo superimposed on the second spin echo, but only in b = 0 images rather than the diffusion-weighted images, leading to over-estimation of ADC and under-estimation of FA. Remedies include appropriate design of crusher gradients or an intentional shift of the echo time.