Quantitative MRI evaluation of glaucomatous changes in the visual pathway

PLoS One. 2018 Jul 9;13(7):e0197027. doi: 10.1371/journal.pone.0197027. eCollection 2018.

Abstract

Background: The aims of this study were to investigate glaucomatous morphological changes quantitatively in the visual cortex of the brain with voxel-based morphometry (VBM), a normalizing MRI technique, and to clarify the relationship between glaucomatous damage and regional changes in the visual cortex of patients with open-angle glaucoma (OAG).

Methods: Thirty-one patients with OAG (age: 55.9 ± 10.7, male: female = 9: 22) and 20 age-matched controls (age: 54.9 ± 9.8, male: female = 10: 10) were included in this study. The cross-sectional area (CSA) of the optic nerve was manually measured with T2-weighed MRI. Images of the visual cortex were acquired with T1-weighed 3D magnetization-prepared rapid acquisition with gradient echo (MPRAGE) sequencing, and the normalized regional visual cortex volume, i.e., gray matter density (GMD), in Brodmann areas (BA) 17, 18, and 19, was calculated with a normalizing technique based on statistic parametric mapping 8 (SPM8) analysis. We compared the regional GMD of the visual cortex in the control subjects and OAG patients. Spearman's rank correlation analysis was used to determine the relationship between optic nerve CSA and GMD in BA 17, 18, and 19.

Results: We found that the normal and OAG patients differed significantly in optic nerve CSA (p < 0.001) and visual cortex GMD in BA 17 (p = 0.030), BA 18 (p = 0.003), and BA 19 (p = 0.005). In addition, we found a significant correlation between optic nerve CSA and visual cortex GMD in BA 19 (r = 0.33, p = 0.023), but not in BA 17 (r = 0.17, p = 0.237) or BA 18 (r = 0.24, p = 0.099).

Conclusion: Quantitative MRI parametric evaluation of GMD can detect glaucoma-associated anatomical atrophy of the visual cortex in BA 17, 18, and 19. Furthermore, GMD in BA 19 was significantly correlated to the damage level of the optic nerve, as well as the retina, in patients with OAG. This is the first demonstration of an association between the cortex of the brain responsible for higher-order visual function and glaucoma severity. Evaluation of the visual cortex with MRI is thus a very promising potential method for objective examination in OAG.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cross-Sectional Studies
  • Female
  • Glaucoma, Open-Angle / diagnostic imaging*
  • Glaucoma, Open-Angle / pathology
  • Gray Matter / diagnostic imaging*
  • Gray Matter / pathology
  • Humans
  • Magnetic Resonance Imaging / methods*
  • Male
  • Middle Aged
  • Optic Nerve / diagnostic imaging*
  • Optic Nerve / pathology
  • Prospective Studies
  • Visual Cortex / diagnostic imaging*
  • Visual Cortex / pathology

Grants and funding

This paper was supported in part by a Japan Science and Technology Agency grant from the Japan Society for the Promotion of Science KAKENHI Grants-in-Aid for Scientific Research (B) (T.N. 17H04349) and for Exploratory Research (T.N. 16K15730), and by the Japan Science and Technology Agency Center for Revitalization Promotion and KAKENHI Grant-in-Aid for young scientists (B) (K.O. 17K16957) and Public Trust Suda Memorial Fund for Glaucoma Research. This work was supported by a Young Investigator Grant of Tohoku University Hospital (Y.T.); ST grant from the Japan Society for the Promotion of Science KAKENHI Grants-in-Aid Young Investigator (B) (Y.T. 26860971); and TUMUG Support Project (Project to Promote Gender Equality and Female Researchers) of Tohoku University (Y.T.).