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Functional MRI of the visual cortex and visual testing in patients with previous optic neuritis
A R Langkilde1, J L Frederiksen, E Rostrup
1Danish Research Centre for Magnetic Resonance, Hvidovre University Hospital, Copenhagen, Norway. annikal@magnet.drcmr.dk
European Journal of Neurology
|May 3, 2002
Summary
Functional magnetic resonance imaging (fMRI) reveals reduced visual cortex activation in patients with optic neuritis (ON). This reduction correlates with visual function tests, suggesting fMRI can assess ON impact and potential cortical reorganization.
Area of Science:
- Neuroscience
- Ophthalmology
- Medical Imaging
Background:
- Optic neuritis (ON) is known to reduce cortical activation in the visual cortex.
- Understanding the extent and cause of this reduction is crucial for patient management.
Purpose of the Study:
- To investigate changes in visual cortical activation (volume and signal intensity) following optic neuritis (ON).
- To correlate fMRI findings with neuroophthalmological test results.
- To assess the utility of fMRI in studying ON, even with severe visual impairment.
Main Methods:
- Functional magnetic resonance imaging (fMRI) with visual stimulation was used.
- Nine patients with previous acute ON and 10 healthy controls were studied.
- Cortical activation volume, BOLD signal increase, and asymmetry were analyzed.
Main Results:
- Patients with ON exhibited reduced visual cortical activation volume and BOLD signal increase compared to controls.
- Greater asymmetry in visual cortex activation was observed in ON patients.
- Activation volume correlated with contrast sensitivity; BOLD signal correlated with contrast sensitivity and visual acuity.
Conclusions:
- fMRI is a valuable tool for studying ON, even in cases of severe visual acuity loss.
- Reduced activation volume may indicate decreased neuronal input.
- Increased asymmetry suggests potential cortical reorganization following neuronal damage.