Signal alteration in the optic nerve head on 3D T2 magnetic resonance imaging: A potential new radiologic imaging sign of glaucomatous optic neuropathy

Abstract

Purpose : Magnetic resonance imaging shows T2 hypointense continuity in the sclera, choroid and lamina cribrosa in healthy subjects. The purpose of the study is to investigate if signal alteration in the optic nerve head on 3D T2-weighted head MRI is associated with glaucomatous optic neuropathy.

Methods : This study included 39 patients with open-angle glaucoma and 31 age-matched healthy volunteers. All subjects underwent 3D 1-mm isovoxel T2-weighted head MR imaging. Peripapillary retinal nerve fiber layer (pRNFL) thickness and optic nerve head parameters including the optic disc area, rim area, cup-to-disc ratio, and cup volume were measured by Cirrus high-definition optical coherence tomography (OCT). Two experimenters blind to subject data reviewed the MR image for the signal alteration in the optic nerve head. If present, they graded the sign as mild or prominent. The prevalence of signal alteration on MR imaging was compared between the two groups. Peripapillary retinal nerve fiber layer (RNFL) thickness and optic nerve head parameters with OCT were compared between subjects with or without the signal alteration.

Results : Signal alteration on 3D T2 MRI was present in 33 of 39 patients with glaucoma (84.6%), and 6 of 31 healthy subjects (19.4%) (p<0.001). The eyes with prominent signal alteration on MRI had thinner average RNFL thickness (71.0 ±17.0 µm vs 92.5 ± 12.1µm) and larger cup volume (0.65±0.34 mm³ vs 0.27±0.37mm³) than the eyes without it (P<0.001, all). Average RNFL thickness (85.2 ± 15.00 µm) and cup volume (0.36 ± 0.25 mm³) between the eyes with mild signal alteration and without it were not statistically different. Disc area was not significantly different among eyes with signal alteration and without it (control eyes: 2.02±0.48 mm², eyes with prominent signal alteration: 2.09±0.45 mm², eyes with mild grade signal alteration: 1.90±0.34mm²).

Conclusions : Signal alteration in the optic nerve head on 3DT2 MRI was more common in open-angle glaucoma than in age-matched healthy control.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

A representative case with unilateral uveitic glaucoma (Left eye). White arrow indicated the signal alteration in left optic nerve head on 3D T2 MRI.