Impact of the number of diffusion gradient directions on measuring values in diffusion tensor imaging / 中国医学影像技术

ABSTRACT

Objective To assess the impact of different number of diffusion gradient directions (NDGD) of diffusion tensor imaging (DTI) on dispersion degree of fractional anisotropy (FA) values and signal-to-noise ratio (SNR) for adult brain tissues. Methods Eight healthy volunteers underwent DTI with 7 NDGD respectively, and the associated FA maps were obtained. Four region of interest (ROI) (genu and splenial of corpus callosum, genu and posterior limb of internal capsule) were chosen in white matter of FA maps, FA values and the corresponding SNRs of the ROIs were computed and analyzed with NDGD increasing. Results FA values within all ROIs did not change remarkably with NDGD increasing. Variance of FA value within two ROIs with high gray value (genu and splenial of corpus callosum) fluctuated randomly and SNR increased slightly, while variance of FA value within the ROIs with low gray value (genu and posterior limb of internal capsule) diminished significantly with NDGD increasing. Conclusion In clinical applications of DTI, an optimum NDGD for DTI data acquisition should be selected according to the ROIs in human brain to be inspected.