Effects of repetition time and field strength on diffusion indices of brain white matter / 中国医学影像技术

ABSTRACT

Objective To observe whether repetition time (TR) and field strengths have effects on diffusion indices of brain white matter. Methods Seven rhesuses underwent diffusion tensor MR imaging (DT-MRI) with a series of TRs (from 500 to 6000 ms) at 1.5T and 3.0T MR scanners, respectively. The mean diffusivity (MD), fractional anisotropy (FA), primary (λ1) and transverse eigenvalues (λ2, 3) were measured in region of interest (ROI) at the posterior limb of internal capsule. Pearson correlation analysis and two-way ANOVA were performed. Results None of the diffusion indices was correlated with TR (P＞0.05) when SNR was high enough (SNR>35). FA was significantly higher and the MD and λ2, 3 were significantly lower at 3.0T than those at 1.5T (P＜0.001). No significant difference of λ1 was found between the two field strengths (P＞0.05). Conclusion Field strength may influence diffusion quantification, but not for TR, which should be considered in multi-center studies.