Retinal and optic nerve magnetic resonance diffusion-weighted imaging in acute non-arteritic central retinal artery occlusion

Abstract

Objectives: Diffusion weighted imaging hyperintensity (DWI-H) has been described in the retina and optic nerve during acute central retinal artery occlusion (CRAO). We aimed to determine whether DWI-H can be accurately identified on standard brain magnetic resonance imaging (MRI) in non-arteritic CRAO patients at two tertiary academic centers.

Materials and methods: Retrospective cross-sectional study that included all consecutive adult patients with confirmed acute non-arteritic CRAO and brain MRI performed within 14 days of CRAO. At each center, two neuroradiologists masked to patient clinical data reviewed each MRI for DWI-H in the retina and optic nerve, first independently then together. Statistical analysis for inter-rater reliability and correlation with clinical data was performed.

Results: We included 204 patients [mean age 67.9±14.6 years; 47.5% females; median time from CRAO to MRI 1 day (IQR 1-4.3); 1.5 T in 127/204 (62.3%) and 3.0 T in 77/204 (37.7%)]. Inter-rater reliability varied between centers (κ = 0.27 vs. κ = 0.65) and was better for retinal DWI-H. Miss and error rates significantly differed between neuroradiologists at each center. After consensus review, DWI-H was identified in 87/204 (42.6%) patients [miss rate 117/204 (57.4%) and error rate 11/87 (12.6%)]. Significantly more patients without DWI-H had good visual acuity at follow-up (p = 0.038).

Conclusions: In this real-world case series, differences in agreement and interpretation accuracy among neuroradiologists limited the role of DWI-H in diagnosing acute CRAO on standard MRI. DWI-H was identified in 42.6% of patients and was more accurately detected in the retina than in the optic nerve. Further studies are needed with standardized novel MRI protocols.

Keywords: Brain MRI; CRAO; DWI; Optic nerve; Retina.

Figure 1.

Flow diagram for patient selection at two tertiary centers. Abbreviation: CRAO, central retinal artery occlusion; MRI, magnetic resonance imaging; DWI, diffusion-weighted imaging.

Figure 2.

Axial DWI for 4 separate patients showing hyperintensity (white arrows) correctly identified in the retina (A) and optic nerve (B). Hyperintensity correctly identified in both the retina and optic nerve (C) with inset image showing corresponding ADC hypointensity in the optic nerve (dashed circle). Hyperintensity correctly identified in the retina but incorrectly identified in the optic nerve (arrowhead) (D). Days between CRAO onset and MR-DWI are listed for each scan. Abbreviation: DWI, diffusion-weighted imaging; ADC, apparent diffusion coefficient; CRAO, central retinal artery occlusion; MR, magnetic resonance.