Apparent Diffusion Coefficient Variabilities of the Optic Nerve in Multiple Sclerosis: Optic nerve head and Intraorbital segment

INTRODUCTION: To investigate the diffusion alterations in the optic nerve head/intraorbital segment in Multiple sclerosis (MS) patients (with or without a history of optic neuritis) in comparison with healthy controls.
METHODS: MS group consisted of 57 patients who had previously been diagnosed with MS. A total of 234 eyes which consisted of 114 eyes of the MS patients and 120 eyes of the healthy controls, were investigated. In 16 of the MS patients had the history of optic neuritis in one eye. The control group was selected from healthy subjects who were matched with MS patients group in terms of gender and age. Echo planar imaging (EPI) sequence was benefitted to attain diffusion-weighted images (DWI). The optic nerve head/intraorbital segment apparent diffusion-coefficient (ADC) values of two groups were compared.
RESULTS: The difference between the optic nerve head/intra-orbital segment ADC values of control group and MS patients was founded statistically considerable (P=0.009, P=0.006, respectively). The difference between the optic nerve head/intra-orbital segment ADC values of MS patients without optic neuritis and control group was also found statistically considerable (P= 0.016, P= 0.026, respectively). It was found that there is a positive correlation between the ADC values and duration of the disease in MS patients (R=0.485/0.428, P<0.01).
DISCUSSION AND CONCLUSION: The ADC values of the optic nerve head/intraorbital segment measured by ocular DWI may have potential for MS patients in the future and this method deserves additional validation in the disease staging and more work to predict patients at risk of optic neuritis.