Study of normal-tension glaucoma based on OCTA and VBM-DARTEL analysis

Area of Science:

• Ophthalmology
• Neuroimaging
• Medical Imaging Analysis

Background:

• Normal-tension glaucoma (NTG) is a progressive optic neuropathy characterized by visual field defects and optic disc damage without elevated intraocular pressure.
• Early detection and monitoring of NTG are crucial for preventing irreversible vision loss.
• Current diagnostic methods may have limitations in detecting subtle structural and functional changes in the early stages of NTG.

Purpose of the Study:

• To evaluate the diagnostic value of optical coherence tomography angiography (OCTA) and voxel-based morphometry with diffeomorphic anatomical registration through exponentiated lie algebra (VBM-DARTEL) in normal-tension glaucoma (NTG).
• To investigate the correlation between OCTA-derived vascular density and VBM-DARTEL-derived brain parenchyma changes in NTG patients.
• To assess the potential of these non-invasive imaging techniques for early diagnosis and monitoring of NTG.

Main Methods:

• A comparative study involving 30 NTG patients and 30 age-, sex-, and education-matched healthy controls.
• Optical coherence tomography angiography (OCTA) was used to measure peripapillary vascular density.
• 3.0 T MRI scans were acquired and processed using VBM-DARTEL to analyze brain structure differences, followed by correlation analysis between imaging parameters.

Main Results:

• Significantly decreased peripapillary vascular density was observed in NTG patients compared to controls, correlating with disease progression.
• VBM-DARTEL analysis revealed reduced volumes in specific brain regions (e.g., middle frontal gyrus, superior frontal gyrus, precuneus, angular gyrus, middle occipital gyrus) and increased volume in the anterior central gyrus in NTG patients.
• The area under the receiver operating characteristic curve for predicting NTG based on brain parenchyma volume differences exceeded 0.7. Brain parenchyma reduction positively correlated with vascular density, while the anterior central gyrus showed a negative correlation.

Conclusions:

• OCTA and VBM-DARTEL are valuable non-invasive tools for detecting structural and functional changes in NTG.
• These techniques provide significant diagnostic imaging support, particularly in the early stages of NTG.
• The combined application of OCTA and VBM-DARTEL holds promise for improved diagnosis and follow-up management of normal-tension glaucoma.