Diffusion Tensor Imaging Evaluations Of Visual Pathways In Multiple Sclerosis Patients With Acute And Chronic Optic Neuritis (P2.290)

OBJECTIVE: We aim to investigate Diffusion tensor imaging(DTI)evaluations of visual pathways in patients with acute and chronic optic neuritis(ON) and assessing to superiority to other evaluation techniques. BACKGROUND:The current application of DTI in ON and multiple sclerosis(MS) shows that the method has enhanced our understanding of their pathophysiology. DESIGN/METHODS:We performed diffusion tensor imaging (DTI) in 26 patients and 13 healthy controls. The patients have acute episode of ON in 17 eyes,chronic ON in 20 eyes and 15 unaffected eyes. In all participants visual afferent system was evaluated with neuro-opthalmological examinations, optical coherence tomography(OCT),visual evoked potential(VEP),orbital and cranial MRI. RESULTS:Fractional anisotropy(FA) in optic nerve were lower in patients with acute ON(0.501±0.098)(p<0.05) and chronic ON(0.476±0.08)(p<0,05) than controls(0.601±0.076).Mean diffusivity(MD) in patients with acute (121.45±23.82) and chronic ON(120.97±18.60) were lower compared to unaffected eyes of patients(108.46±16.31)and controls (92.55±11.68 p<0.05). Retinal nerve fiber layer thickness(RNLFT),P100 amplitude and latency and visual acuity(VA) were significantly different between groups(P <0.01).Eyes with abnormal orbital MRI findings have statistically significant decrease in FA (p< 0.05),increase in MD(p<0.01),prolonged P100 latency(p <0.01) and decrease P100 amplitude(p<0.05),decrease in RNLFT(p<0,05) and VA.MD measured in optic chiasm was increased in patient group(p<0.05). FA and MD measured in optic tract was significantly different (p<0,05) between groups.In the correlation analysis; FA in optic nerves were correlated with P100 latency and RNLFT(p<0.05) in acute ON. MD were correlated with RNLFT,VA(p<0.05) and P100 latency.RNLFT was correlated with VA in acute ON. FA values were correlated with MD values and VA(p<0.05). MD were correlated with P100 amplitude and VA in chronic ON(p<0.05). CONCLUSIONS:Briefly,the abnormalities of MD and FA in DTI for the optic nerve were more severe compared to chiasm and optic tract. Our results suggested that DTI derived measurements correlate with visual disability and tissue injury and therefore they are important both from a clinical point of view and understanding of pathological processes. Study Supported by:This study was supported by TUBITAK (The scientific and technological research council of Turkey). Disclosure: Dr. Keskin has nothing to disclose. Dr. Idiman has nothing to disclose. Dr. Ozkan has nothing to disclose. Dr. Ada has nothing to disclose. Dr. Saatci has nothing to disclose. Dr. Idiman has nothing to disclose.