Quantitative 3-T diffusion tensor imaging in detecting optic nerve degeneration in patients with glaucoma: association with retinal nerve fiber layer thickness and clinical severity.
BACKGROUND
To investigate the association of quantitative 3-T diffusion tensor imaging (DTI) with retinal nerve fiber layer (RNFL) thickness measured by optical coherence tomography (OCT) and clinical severity in detecting optic nerve degeneration in patients with primary closed-angle glaucoma.


METHODS
Twenty three patients (42 eyes; 9 men, 14 women) with primary closed-angle glaucoma and 20 healthy controls were enrolled in this study. Both DTI and OCT were performed on the optic nerves of all subjects. The mean diffusivity (MD), fractional anisotropy (FA), and eigenvalue maps were obtained for quantitative analysis. RNFL thickness and quantitative electrophysiology were also performed on all subjects. The association of quantitative DTI with RNFL thickness and glaucoma stage was analyzed.


RESULTS
Compared with control nerves, the FA, λ[parallel], and λ[perpendicular] values, and RNFL thickness in affected nerves decreased, while MD increased in patients with primary glaucoma (p < 0.05). There was a significant correlation between FA, MD, λ[parallel], and λ[perpendicular] and the mean RNFL thickness (P < 0.01). The mean FA and λ[perpendicular] values derived with DT MR imaging correlated well with glaucoma stage (P < 0.05), but the mean MD and λ[parallel] values did not correlate with glaucoma stage (P > 0.05).


CONCLUSIONS
DTI measurement could detect abnormality of the optic nerve in patients with glaucoma and may serve as a biomarker of disease severity.
Department of Radiology, Henan Provincial People's Hospital & the People's Hospital of Zhengzhou University, 7 Weiwu Rd., Zhengzhou, Henan 450003, China.
Mei-Yun
MY
Wang
Ke
K
Wu
Jun-Min
JM
Xu
Jianping
J
Dai
Wei
W
Qin
Jiangang
J
Liu
Jie
J
Tian
Dapeng
D
Shi
D000328:Adult; D000368:Aged; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000150:complications* / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009900:Optic Nerve / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000150:complications* / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013223:Statistics as Topic