Functional Magnetic Resonace Imaging In Patients With Optic Neuritis

Objective To establish the role of cortical neuroplasticity changes in examinations of patients with optic neuritis by using functional magnetic resonance imaging(fMRI).We compare the the results of the fMRI imaging,the central 15 degree visual field examination and pattern-visual evoked potential(P-VEP) to investigate the diagnosis and other informations of optic neuritis by fMRI.Subjects and Methods Subjects:Seventeen patients with optic neuritis seen from 2008.3 to 2009.3 in Huashan Hospital of fudan university.Methods:static visual field perimetry with Octopus101 perimeter, pattern-visual evoked potential,fMRI and visual tests were performed. Visual tests:visual acuity,pupillary light reflex and fundus of eye. P-VEP:We tested every patient's both eye by using RETI-port_gamma eye electrophysiology program,and the visual stimuli subtended a field of view of about 12×16 square degrees.The latency and amplitude of P100 wave was quantitatively analyzed,fMRI:Visual stimuli:The stimuli subtended a field of view of about 12 degrees,consisted of high contrast, drifting checkerboards.Two types of stimuli were used:the annular ring, either contracting or expanding,was used to map eccentricity and the rotating wedge,either clockwise or counterclockwise,was used to map the polar angle.MRI parameters:GE signa VH/i 3.0T scanner.Functional data: GRE-EPI sequence,20 slices lying perpendicular to the caicarine sulcus. Anatomical data was obtained using 3D-SPGR sequence to acquire high resolution.Functional data was presented to the inflated surface and subsequently analyzed by SPM5 software.Results Occipital cortex,inferior temporalgyrus,and postparietalgynus angularis were activated in patients of optic neuritis.The most of the activated areas were lacated around the fissure of occipital cortex.To parts of the patients,both the activated voxel number and the average signal intensity in stimulation of affected eye were lower than those in stimulation of unaffected eye.The mean degect of central 15 degree of visual field and the number of activated voxels in cortex was inverse correlation.The amplitude of P100 wave and the number of activated voxels in cortex were positive correlation.The area of activated voxels in cortex was manifest dilatation in parts of the patient,and their clinical history promote bad prognosis.Conclusion fMRI of visual activation reliable reflects the cerebral consequences of acute optic neuritis,it might provide clinically relevant information in diagnosis and appraisal the prognosis of optic neuritis.