Functional alterations of V1 cortex in patients with primary open angle glaucoma using functional MRI retinotopic mapping / 中华放射学杂志

ABSTRACT

Objective To evaluate the functional changes of visual cortex (V1) in patients with primary open angle glaucoma (POAG) by fMRI retinotopic mapping technology. Methods Fifteen POAG patients and 15 healthy volunteers underwent stimulations with fMRI retinotopic mapping stimulus and contrast-reversing checkerboard patterns stimulus on a Siemens Trio 3.0 T MRI whole-body scanner for functional data collection. Comparisons of V1 fMRI responses between the glaucomatous eyes and the healthy eyes of the patients were carried out using paired samples t-test, while independent samples t-test was used to compare V1 fMRI responses and activations between the healthy eyes of patients and the age-, gender- and side- matched eyes of normal people. Differences of V1 cortical functions and visual functions were analyzed by linear correlation analysis when the glaucomatous and the healthy eyes were simulated individually. Results (1) V1 fMRI responses of the individually stimulated glaucomatous eyes[(1.24±0.72)%]were weaker than those of the healthy eyes[(2.18±0.93)%](t=4.757,P<0.01). Comparisons of V1 fMRI responses between the glaucomatous eyes and matched eyes of normal people, as well as between the healthy eyes of patients and the matched eyes of normal people, were performed respectively the responses in the glaucomatous eyes[(1.24±0.72)%]were weaker than those in the matched eyes of normal people[(2.01±0.65)%](t=-3.011,P<0.01). There was no statistical difference of the responses between the healthy eyes from patients[(2.18±0.93)%]and the matched eyes of normal people[(1.95±0.75)%](t=0.742,P＞0.05). (2) Differences of V1 cortical functions were negatively correlated with those of visual functions in the individually stimulated glaucomatous and healthy eyes (r=-0.887, P<0.01). (3) The activated area indexes of V1 cortexes in the healthy eyes from patients (0.72±0.12) were lower than those in the matched eyes of normal people (0.85±0.09) (t=-3.801, P<0.01). Conclusion Cortical function impairment was in accordance with visual function impairment in glaucoma. Located and quantified measurement with fMRI retinotopic mapping was a useful method for clinical follow-up and evaluation of functional alteration of glaucomatous visual cortex, and a potentially useful means of studying trans-synaptic degeneration of visual pathways of in vivo glaucoma.