Magnetic resonance diffusion tensor imaging for optic nerves and optic radiation in blind patients / 中华眼底病杂志

ABSTRACT

Objective To observe the characteristics of magnetic resonance diffusion tensor imaging (MR-DTI)for optic nerves and optic radiation in blind patients. Methods The optic nerves and optic radiation of 20 blind patients (blind group) and 20 controls (control group) were scanned by MR-DTI.Fractional anisotropy (FA) and directional encoded color (DEC) maps were acquired through postprocessing with the aid of volume-one 1. 72 software. The signal intensity of optic nerves and optic radiation were then observed. The FA, mean diffusivity (MD), λ∥ and λ⊥ value of bilateral optic nerves and optic radiation in two groups were measured in the DEC maps. Results While the high signal intensity was found in bilateral optic nerves in FA and DEC maps in control group, the signal decreased markedly in the blind group. The FA and λ∥ value of optic nerves in the blind group were declined obviously compared to that in the control group. The difference was statistically significant (t= 16. 294, 14. 660;P=0. 000). The MD and λ⊥ value of optic nerves in the blind group were increased obviously compared to that in the control group, the difference was also statistically significant (t=8. 096, 8. 538;P = 0. 000). The high signal intensity was found in bilateral optic radiation in FA and DEC maps in both the blind and control groups. There were no statistic differences in FA and MD value in bilateral optic radiation between the blind and control groups (Leftt=1.456,1.811;P = 0. 152,0.076. Rightt = 0. 779,0. 073;P = 0. 440,0. 942). Conclusion A low signal intensity of bilateral optic nerves and a high signal intensity of bilateral optic radiation were found in blind patients.