Serial Diffusion Tensor Imaging of the Optic Radiations after Acute Optic Neuritis

Scott C Kolbe; Anneke van der Walt; Helmut Butzkueven; Alexander Klistorner; Gary F Egan; Trevor J Kilpatrick

doi:10.1155/2016/2764538

Serial Diffusion Tensor Imaging of the Optic Radiations after Acute Optic Neuritis

J Ophthalmol. 2016:2016:2764538. doi: 10.1155/2016/2764538. Epub 2016 Jul 31.

Authors

Scott C Kolbe¹, Anneke van der Walt², Helmut Butzkueven³, Alexander Klistorner⁴, Gary F Egan⁵, Trevor J Kilpatrick⁶

Affiliations

¹ Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC 3010, Australia; Florey Institute of Neuroscience and Mental Health, Parkville, VIC 3010, Australia.
² Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC 3010, Australia; Department of Neurology, Royal Melbourne Hospital, Parkville, VIC 3052, Australia.
³ Department of Neurology, Royal Melbourne Hospital, Parkville, VIC 3052, Australia; Department of Medicine, University of Melbourne, Parkville, VIC 3010, Australia.
⁴ Save Sight Institute, University of Sydney, Sydney, NSW 2000, Australia.
⁵ Monash Biomedical Imaging, Monash University, Clayton, VIC 3800, Australia.
⁶ Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC 3010, Australia; Florey Institute of Neuroscience and Mental Health, Parkville, VIC 3010, Australia; Department of Neurology, Royal Melbourne Hospital, Parkville, VIC 3052, Australia.

Abstract

Previous studies have reported diffusion tensor imaging (DTI) changes within the optic radiations of patients after optic neuritis (ON). We aimed to study optic radiation DTI changes over 12 months following acute ON and to study correlations between DTI parameters and damage to the optic nerve and primary visual cortex (V1). We measured DTI parameters [fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD)] from the optic radiations of 38 acute ON patients at presentation and 6 and 12 months after acute ON. In addition, we measured retinal nerve fibre layer thickness, visual evoked potential amplitude, optic radiation lesion load, and V1 thickness. At baseline, FA was reduced and RD and MD were increased compared to control. Over 12 months, FA reduced in patients at an average rate of -2.6% per annum (control = -0.51%; p = 0.006). Change in FA, RD, and MD correlated with V1 thinning over 12 months (FA: R = 0.450, p = 0.006; RD: R = -0.428, p = 0.009; MD: R = -0.365, p = 0.029). In patients with no optic radiation lesions, AD significantly correlated with RNFL thinning at 12 months (R = 0.489, p = 0.039). In conclusion, DTI can detect optic radiation changes over 12 months following acute ON that correlate with optic nerve and V1 damage.