Optic Nerve MRI Signal Alterations in Dural Arteriovenous Fistulae: Correlations With Papilledema and Visual Decline

Visual decline in dural arteriovenous fistulae (DAVF) patients is attributed to venous hypertension, raised intracranial pressure and resultant optic nerve axoplasmic flow stasis. Objective imaging biomarkers for optic nerve involvement are however limited.

To determine whether 3D fluid attenuated inversion recovery (FLAIR) optic nerve signal intensity ratio (SIR) is associated with papilledema and visual deterioration in DAVF patients.

Single-center retrospective observational study.

54 digital subtraction angiography (DSA) confirmed DAVF patients (27 with papilledema; 27 without) with 3D FLAIR MRI, together with 27 matched controls.

3D FLAIR sequence at 3.0 T.

Three blinded neuroradiologists evaluated segmental normalized optic-nerve SIR. The primary outcome was status of papilledema (fundoscopy)/visual deterioration (Snellen's visual acuity charting). Secondary outcomes included segmental optic nerve hyperintensity (measured by SIR and qualitative assessment) and visual response (improved, stable or worsened visual acuity) post-embolization. All patients underwent endovascular embolization with repeat neuro-ophthalmologic evaluation and imaging (short term followup at 1 month and long term at 1 year).

Unpaired t-test, Mann-Whitney U, repeated-measures ANOVA, Receiver Operating Characteristic (ROC) curve; Interobserver agreement with Krippendorff's alpha and intraclass correlation coefficient (ICC); Correlation analysis with Spearman correlation; p value < 0.05 was considered significant.

Optic nerve SIR differed significantly across groups, with highest values in patients with visual decline. The intracanalicular segment was most commonly involved (51.8%). An SIR cutoff of 1.7 showed association of papilledema with visual loss (AUC = 0.725; 95% CI: 0.608-0.858; 48.2% had visual deterioration), yielding 79.2% sensitivity and 63.3% specificity. Follow-up included repeat ophthalmologic evaluation and imaging, with 23.1% patients showing improvement at a mean follow-up of 1.7 ± 1.6 years.

3D FLAIR MRI may detect optic nerve signal changes in DAVF patients, with elevated intracanalicular SIR correlating with papilledema and visual decline.

4.

Stage 5.