Alterations of the optic pathway between unilateral and bilateral optic nerve damage in multiple sclerosis as revealed by the combined use of advanced diffusion kurtosis imaging and visual evoked potentials.
We investigated changes in the optic tract and optic radiation in patients with multiple sclerosis (MS) by comparing unilateral and bilateral optic nerve damage assessed based on visual evoked potentials (VEPs) using advanced diffusion MR metrics.



In 21 MS patients, diffusion MRI was performed. Maps of fractional anisotropy, apparent diffusion coefficient (ADC), and mean kurtosis (MK) were computed. On the basis of the P100 latency in VEPs, the MS patients were divided into three groups: bilateral (n=7), unilateral (n=7), and no abnormality (n=7). Their optic tracts and optic radiations were analyzed with diffusion MRI-based fiber tracking. We also investigated the correlations between diffusion parameters and VEPs (n=21).



In the optic tract, the diffusion changes in each of the three groups showed step-like changes. The diffusion changes in the optic radiations of the unilateral group were similar to those in the normal VEP group. Only the bilateral group showed significantly higher ADC and lower MK relative to the other two groups (P<0.05, Steel-Dwass multiple-comparison test). A significant positive correlation between VEP latency and ADC and a significant negative correlation between VEP latency and MK were observed (P<0.01, Spearman's correction).



We first evaluated the relationship between VEPs and DKI and concluded that the lateral geniculate nucleus may compensate for unilateral damage in the pre-geniculate optic pathway via neural plasticity.
Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan. Electronic address: mrk.ysd@gmail.com.
Mariko Yoshida
MY
Takemura
Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
Masaaki
M
Hori
Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan.
Kazumasa
K
Yokoyama
Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
Nozomi
N
Hamasaki
Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
Michimasa
M
Suzuki
Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
Koji
K
Kamagata
Division of Radiology, and Biomedical Engineering, Graduate School of Medicine, The University of Tokyo.
Kouhei
K
Kamiya
Philips Electronics Japan, Tokyo, Japan.
Yuriko
Y
Suzuki
Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
Shinsuke
S
Kyogoku
Medical Imaging Laboratory, Graduate School of Information Sciences, Hiroshima City University.
Yoshitaka
Y
Masutani
Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan.
Nobutaka
N
Hattori
Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
Shigeki
S
Aoki
D000328:Adult; D016880:Anisotropy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005074:Evoked Potentials, Visual; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000000981:diagnostic imaging*; D009412:Nerve Fibers / Q000473:pathology; D009900:Optic Nerve / Q000000981:diagnostic imaging*; D065866:Optic Tract / Q000000981:diagnostic imaging*; D012720:Severity of Illness Index
Bilateral and unilateral optic nerve damage; Diffusional kurtosis imaging; Multiple sclerosis; Tractography; Visual evoked potentials