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T. Yamamoto, K. Yamada, T. Nishimura, S. Kinoshita; Prognostic Value of Diffusion Tensor Imaging in Acute Optic Neuritis . Invest. Ophthalmol. Vis. Sci. 2005;46(13):639.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Diffusion tensor imaging (DTI) enables observation of the intrinsic directionality of water diffusion in vivo, which may provide a more direct way of investigating events occurring in optic neuritis at microscopic level than can be obtained with conventional MR imaging techniques. This is achieved through the measurement of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA). The purpose of this pilot study was to determine whether measuring these parameters in patients with acute optic neuritis, provided insight regarding the mechanisms of neuronal damage, and could improve prediction of the patients’ visual prognosis. Methods: Subjects were 4 consecutive patients with their first episode of unilateral acute optic neuritis. The patients were examined twice, within a week and again 3 months after the onset of visual symptoms, by means of best visual acuity and DTI parameters. DTI data was obtained using a 1.5–Tesla whole–body scanner (Gyroscan Intera, Philips Medical Systems), and transferred to an off–line workstation for image analysis. Two regions of interest (ROI) of 2 mm diameter were placed in the orbital part of the bilateral optic nerves on coronal brain section, and then ADC and FA ratio (affected/fellow eye) were calculated. Results: The lesions were classified into two subgroups regarding Snellen visual acuity of the 3–month follow–up (>20/25, cases #1–3; no light perception, case #4). In cases #1–3, ADC ratio was (1.47±0.14) at the initial examination, and (1.19±0.08) at the 3–month follow–up; in case #4, ADC ratio was (0.97) and (1.06), respectively. All cases showed similar decrease in FA ratio (0.59±0.08) at the initial examination. At the 3–month follow–up, FA ratio was (0.90±0.13) in cases #1–3; (0.61) in case 4. Conclusions:In this small series, it has been implied that DTI may be able to give information that predicts the prognosis about the visual recovery in optic neuritis: Eyes with high ADC in acute optic neuritis had a good prognosis for visual recovery, while almost unchanged ADC led to poor visual recovery. Eyes with good prognosis showed restoration of the decreased FA at 3–month follow–up. Our data may warrant further clinical investigation in this field.
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