Assessment of nonarteritic anterior ischemic optic neuropathy with intravoxel incoherent motion diffusion-weighted imaging using readout-segmented echo-planar imaging, parallel imaging, and 2D navigator-based reacquisition

Abstract

Purpose: To determine the feasibility of intravoxel incoherent motion (IVIM) for characterizing perfusion properties and its potential diagnostic utility for nonarteritic anterior ischemic optic neuropathy (NAION). IVIM diffusion-weighted imaging is a promising technique that can measure perfusion and diffusion characteristics simultaneously in a noninvasive manner. Materials and Methods: Orbital IVIM in a 3.0T scanner was performed on 33 patients with NAION and 15 controls using readout-segmented echo-planar imaging, parallel imaging, and 2D navigator-based reacquisition (RESOLVE-IVIM). Both visual field (VF) and visual acuity (VA) examinations were performed in 19 of the patients. The vascular volume fraction (f), diffusion coefficient (D), and pseudodiffusion coefficient (D*) were calculated for quantitative analysis. Additionally, correlation analyses of IVIM parameters with visual function were also performed. Results: Affected optic nerves showed significantly lower f values than both unaffected contralateral nerves of the patients and nerves of the controls (P < 0.0001), and no significant difference for f was found between unaffected contralateral nerves and nerves of the controls (P = 0.1602). In addition, D and D* values showed no significant differences among the three groups (P = 0.0979, 0.0600, 0.6136 for D and 0.1779, 0.6253, 0.4743 for D*). Correlation analysis only demonstrated significant correlations between f values and the mean deviation of the visual field (r = 0.576, P = 0.0051). Conclusion: RESOLVE-IVIM measurement may reflect the perfusion abnormality and visual function impairment in NAION patients, demonstrating its potential application for the diagnosis and clinical evaluation of NAION. Level of Evidence: 1. Technical Efficacy: Stage 3. J. Magn. Reson. Imaging 2017;46:1760–1766.