Inexpensive OCT glaucoma assessment tool can track MS activity

Jan. 16, 2008

January 16, 2008, Buffalo, NY--New research by neurologists at the University at Buffalo has shown that optical coherence tomography (OCT) also could be used as a surrogate marker of disease status in multiple sclerosis (MS) and to assess the effectiveness of new and current MS treatments.

Magnetic resonance imaging (MRI) of the brain is the gold standard for monitoring the progression of MS, but it is expensive and comes with limitations, one of which is the inability to assess fully the extent of loss of neurons.

"MRI has advanced our ability to measure tissue injury in MS, but the technology cannot specifically measure changes in axonal integrity," said Bianca Weinstock-Guttman, M.D., the study's corresponding author and associate professor of neurology in the Jacobs Neurological Institute, which is the Department of Neurology in the UB School of Medicine and Biomedical Sciences.

"OCT may be helpful in monitoring disease progression, but also could represent a potential sensitive tool or outcome measure for future trials using neuroprotective therapeutic interventions. It is considered a reliable and objective technique for capturing loss of retinal ganglion cell axons in early glaucoma and in other forms of optic neuropathy." Optic neuropathy (ON) is the initial presenting sign in 20% to 25% of MS patients.

Weinstock-Guttman noted that the retina is unique as a model of neurodegeneration and neuroprotection because it contains no myelin. "This organization is advantageous because changes in the structure of the retinal-nerve-fiber layer principally represent axonal damage, whereas the myelin wrapping around the axons into the optic nerve begins behind the eye. Consequently, the retina can be used to focus on the neuronal and axonal components of MS pathological changes."

The study involved a retrospective review of scans of 30 patients with relapsing-remitting MS (characterized by acute attacks with full or partial recovery) who were seen at the Baird Multiple Sclerosis Center, the clinical section of the JNI. All patients had received OCT, and 18 were analyzed also by MRI. All scans were analyzed at the Buffalo Neuroimaging Analysis Center, also part of UB's JNI.

Results showed that the thickness of the retinal-nerve-fiber layer (RNFL) as assessed by OCT was strongly associated with MRI findings of brain atrophy and lesion volume, according to Weinstock-Guttman. They also found a negative correlation between average RNFL thickness (average of both eyes) and disability, as assessed by the Expanded Disability Status Scale, the gold standard measure used in MS.

"The results demonstrate that OCT can be an excellent patient monitoring technique, because the decrease in RNFL thickness reflects inflammatory and neurodegenerative components of MS," she said. "Further studies are needed to assess and validate OCT measures versus MRI measures and to delineate the role of OCT in patients with relapsing and progressive forms of MS.

Erica Grazioli, M.D., UB clinical instructor of neurology, was first author on the paper. Additional contributors were Robert Zivadinov, M.D., Ph.D., director of the BNAC and UB associate professor of neurology; Norah Lincoff, M.D., UB clinical professor of ophthalmology; Jan Rang Wong; David Hojnacki, M.D., clinical instructor of neurology; Sara Hussein; Jennifer Cox, Ph.D., assistant professor neurology and director of clinical imaging at the BNAC; Murali Ramanathan, Ph.D., UB associate professor of neurology and pharmaceutical sciences, and Monica Baier, Ph.D., from the University of Alabama.