Hui Dai PhD, Abstract Co-Author: Nothing to Disclose

Xing Deng, Abstract Co-Author: Nothing to Disclose

Yonggang Li MD, Abstract Co-Author: Nothing to Disclose

John Nicholas Morelli MD, Presenter: Nothing to Disclose

Fei Ai MD, Abstract Co-Author: Nothing to Disclose

Liang Guo, Abstract Co-Author: Nothing to Disclose

Chengyuan Wang, Abstract Co-Author: Nothing to Disclose

To prospectively investigate dorsal visual pathway neurodegeneration in patients with primary open-angle glaucoma (POAG) utilizing 3T diffusion tensor imaging (DTI) and to explore whether DTI parameters correlate with disease severity.

The study was approved by the institutional review board. 24 patients with known POAG and 24 age-matched healthy volunteers were examined. All subject underwent imaging on a 3T MR system utilizing a DT sequence(TR/TE 13000/68.9 msec, slice thickness 2 mm without interslice gaps, matrix 128×128, field of view 240 mm2, number of signal averages (NEX) 2, maximal b value 800 sec/mm2 along 30 directions, scan time 13′39〞)and a BRAVO sequence to provide a structural view for DTI (TR/TE/TI 6.8/3.5/380 msec, slice thickness 1 mm without interslice gaps, matrix 256×256, field of view 240 mm2, NEX 1, bandwidth 42 Hz, flip angle 15°, scan time 2′43〞). All the original data were processed by tract-based spatial statistical(TBSS) analysis, a part of FMRIB soft library(FSL). Mean diffusivity (MD) and fractional anisotropy (FA) maps of dorsal visual pathway in the POAG patients were compared with the healthy controls and the correlation between the POAG group and the clinical stages were also valued.

The dorsal visual pathway of patients with glaucoma, as compared with control subjects, had significantly higher MD of POAG group((1.24±0.41）×10-3 mm2/sec versus control group （1.11±0.31）×10-3 mm2/sec, p<10-3))and significantly lower FA(mean value of POAG group 0.46±0.13 versus control group 0.56±0.10, p<10-3). The mean MD values for the dorsal visual pathway were positively correlated with glaucoma stages (r=0.597，p<10-3) while the mean FA values were negatively correlated with glaucoma stages (r=-0.793，p<10-3).

Glaucoma is a neurologic degenerative disease that affects dorsal visual pathway. Our finding that the value of DTI parameters (MD and FA ) in the dorsal visual pathway correlate with glaucoma severity suggests that these parameters could serve as complementary indicators of disease severity.

Based on the findings, TBSS would be a potential assistant method in diagnosis of glaucoma and may provide a new biomarker of early stage of the disease.

Dai, H, Deng, X, Li, Y, Morelli, J, Ai, F, Guo, L, Wang, C, Dorsal Visual Pathway Neurodegeneration in Patients with Primary Open Angle Glaucoma: In Vivo Analysis with 3 T Diffusion-Tensor MR Imaging.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11004238.html