Standard Diffusion-weighted MRI for the Diagnosis of Central Retinal Artery Occlusion

L A Danyel,G Bohner,F Connolly,E Siebert

doi:10.1007/s00062-020-00955-6

Abstract

PurposeTo evaluate diffusion abnormalities of the retina and optic nerve in patients with central retinal artery occlusion (CRAO) using standard stroke diffusion-weighted magnetic resonance imaging (DWI).MethodsIn this case-control study, DWI scans of patients with nonarteritic CRAO were retrospectively assessed for acute ischemia of the retina and optic nerve. Two neuroradiologists, blinded for patient diagnosis, randomly evaluated DWI of CRAO patients and controls (a collective of stroke and transient ischemic attack [TIA] patients) for restrictions of the retina and optic nerve. We calculated statistical quality criteria and analyzed inter-rater reliability using unweighted Kappa statistics.Results20 CRAO patients (60,6 ± 17 years) and 20 controls (60,7 ± 17 years) were included in the study. Sensitivity, specificity, positive and negative predictive values for retinal DWI restrictions were 75%/80%/79%/76% (reader 1) and 75%/100%/100%/80% (reader 2), respectively. Unweighted Kappa was κ = 0,70 (95% CI 0,48‑0,92), indicating “substantial” interrater reliability. In comparison, sensitivity, specificity, PPV and NPV (positive and negative predictive values) for restrictions of the optic nerve in CRAO were 55%/70%/65%/61% (reader 1) and 25%/100%/100%/57% (reader 2). Inter-rater reliability was “fair” with unweighted Kappa κ = 0,32 (95% CI 0,09‑0,56).ConclusionsRetinal diffusion restrictions were present in a majority of CRAO patients and detectable with reasonable sensitivity, high specificity and substantial inter-rater reliability. Further studies are necessary to study time dependency of retinal diffusion restrictions, improve image quality and investigate the reliability of retinal DWI to discern CRAO from other causes of acute loss of vision.

Highlights

Nonarteritic central retinal artery occlusion (NA-CRAO) is a medical emergency characterized by a sudden onset of painless, monocular amaurosis due to retinal ischemia
Retinal findings included (1) a thin line of hypersignal along the inner aspect of the globe forming a U-shape and extending from the optic nerve head bilaterally up to or beyond the ora serrata, (2) a diffusion-weighted imaging (DWI) hypersignal on either side of the optic nerve head nasally or temporally along the inner aspect of the globe, in most cases not extending to the ora serrata or (3) a mild regional hypersignal of the inner aspect of the globe with a mildly thickened depiction in comparison to the remaining parts of the globe. In this preliminary retrospective case-control study retinal diffusion abnormalities can be seen in the majority of patients with CRAO on standard brain DWI
Using standard stroke DWI magnetic resonance imaging (MRI) at 1.5T or 3 T, we found retinal DWI restrictions in 75% of the CRAO patients from our cohort

Summary

Introduction

Nonarteritic central retinal artery occlusion (NA-CRAO) is a medical emergency characterized by a sudden onset of painless, monocular amaurosis due to retinal ischemia. CRAO is mainly caused by emboli originating from large artery atherosclerosis [3,4,5] or car-. As the risk of recurrent cardiovascular events, including stroke, is elevated and dependent on CRAO etiology, a thorough diagnostic work-up is required [15,16,17,18]. Brain magnetic resonance imaging (MRI) is increasingly performed in CRAO patients. Acute ischemic lesions are found in approximately 25% of CRAO patients [19, 21, 22]. To the best of our knowledge, no systematic MRI studies related to distinctive retinal features in CRAO have been published [26, 27]

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