Imaging technique looks beneath the surface	May 2009

By Colette Pilkus

The emerging technology of optical coherence tomography, or OCT, is being put to use in the diagnosis of a variety of central nervous system diseases. An optical signal acquisition and processing method, OCT allows researchers to take high-quality, micrometer-resolution, three-dimensional images from within biological tissue.

OCT is gaining traction in the medical community because of its ability to provide tissue morphology imagery at a higher resolution than other imaging modalities such as MRI or ultrasound. Benefits of OCT include real-time sub-surface images at near-microscopic resolution, instant, direct imaging of tissue morphology, no preparation of the tissue sample, and no ionizing radiation. OCT also has the advantage of repeated imaging over a period of time to monitor the progression of a disease or response to therapy.

Sanofi-Aventis has been employing the technology in the company’s study of nerispirdine on visual function in patients with multiple sclerosis. The study’s objective is to evaluate the effect of nerispirdine 50 milligrams or 400 milligrams on latency of visual evoked potentials P100 in optic nerves. OCT is being used for defining etiologic relationships and for assessing the effect of treatment of age-related eye disease versus the multiple sclerosis-related vision impairment.

“[OCT] is an incredible tool for examination of patients and scientific follow-up on treatment results and monitoring of disease progression or regression,” says Artur Wamil, clinical research director of neurology at Sanofi-Aventis (sanofi-aventis.com).

In the future, OCT may be studied to guide excisional biopsy to reduce false negatives and improve imaging sensitivity. There is interest in using the technique to guide surgical interventional procedures such as stent placement. OCT has also shown promise in intravascular imaging to examine plaque in coronary arteries.