Tharani, N M (2018) Diffusion weighted imaging as a predictor of visual outcome in acute optic neuritis. Masters thesis, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Madurai.
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Abstract
INTRODUCTION: Optic neuritis is an inflammation of optic nerve. Based on clinical examination it is classified into retrobulbar neuritis, papillitis or neuroretinitis. Etiology is multifactorial. The usual triad of symptoms consist of ipsilateral eye pain, vision loss and dyschromatopsia. Clinical signs include reduced visual acuity, dyschromatopsia, altered contrast sensitivity, afferent pupillary defect, visual field defects, optic disc and retinal changes. 25% - 30% is usually found associated with Multiple sclerosis. MRI remains the imaging modality of choice in diagnosing and in assessing the visual outcome in optic neuritis. More data is provided by Diffusion-weighted and diffusion-tensor imaging on treatment and/or on prognosis. The loss of anisotropy manifested by an increase in the apparent diffusion coefficient or associated with demyelination and/or axonal damage may be more sensitive and/or yield more prognostic information than anatomic imaging findings. The shortcoming of diffusion -weighted and diffusion-tensor imaging of the optic nerves are that it is too time consuming. The main stay of treatment in optic neuritis based on ONTT (Optic Neuritis Treatment Trial) is corticosteroids both intravenous and oral at present, although newer treatment modalities are underway. AIM OF THE STUDY: To determine that Diffusion weighted imaging can be used as a predictor of visual outcome in patients with Acute optic neuritis at a tertiary eye care Centre in Southern India. OBJECTIVES: 1. To detect acute optic neuritis by MRI. 2. To determine that DWI can be used as a predictor of visual outcome in acute optic neuritis. 3. To determine the specificity of Diffusion restriction, contrast enhancement and ADC in detecting acute optic neuritis. METHODOLOGY: It is a hospital based prospective, observational study. 31 eyes of 28 patients with acute optic neuritis who attended the hospital between December 2015 and December November 16 was statistically analysed, with a follow up period of 3 months. RESULTS: Mean age was 34 ±10.27 (SD) years. The mean duration of onset of symptoms was 9.11 days ± 6.95 (SD). 64.3% of the patients were females. Left eye was involved in 15 cases (60%). Defective vision was the main complaint in 31 eyes (100%). RAPD was found in 28 eyes. At baseline presentation optic disc showed disc edema in 70.9% of eyes. Colour vision, brightness sensitivity, red desaturation which were abnormal in a majority of patients showed good improvement in significant number of patients post treatment. Median LogMAR at baseline was 1.32 ± 0.86 which improved to 0.14 ± 0.24. After 3 months after treatment with intravenous and oral steroids as recommended by optic neuritis treatment trial. In Diffusion weighted imaging (DWI) diffusion was restricted in 83.9% eyes, contrast was enhanced in 83.9% eyes, optic nerve diameter was increased in 87%and apparent diffusion coefficient (ADC) was reduced in 83.9% eyes at baseline. These eyes showed good prognosis at 3 months follow up compared to eyes which had no diffusion restriction, no contrast enhancement and increased ADC. CONCLUSION: Diffusion weighted imaging (DWI) adds value in predicting the visual outcome in acute optic neuritis.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Diffusion weighted imaging (DWI) ; Apparent Diffusion Coefficient (ADC) ; optic neuritis. |
| Subjects: | MEDICAL > Ophthalmology |
| Depositing User: | Subramani R |
| Date Deposited: | 14 Jul 2018 20:22 |
| Last Modified: | 14 Jul 2018 20:22 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/8809 |
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