Optical coherence tomography in the diagnosis and treatment of neurological disorders

Abstract

Optical contrast is often the limiting factor in the imaging of live biological tissue. Studies were conducted in postmortem human brain to identify clinical applications where the structures of interest possess high intrinsic optical contrast and where the real-time, high-resolution imaging capabilities of optical coherence tomography (OCT) may be critical. Myelinated fiber tracts and blood vessels are two structures with high optical contrast. The ability to image these two structures in real time may improve the efficacy and safety of a neurosurgical procedure to treat Parkinson's disease called deep brain stimulation (DBS). OCT was evaluated as a potential optical guidance system for DBS in 25 human brains. The results suggest that catheter-based OCT has the resolution and contrast necessary for DBS targeting. The results also demonstrate the ability of OCT to detect blood vessels with high sensitivity, suggesting a possible means to avoid their laceration during DBS. Other microscopic structures in the human brain with high optical contrast are pathological vacuoles associated with transmissible spongiform encephalopathy (TSE). TSE include diseases such as Mad Cow disease and Creutzfeldt-Jakob disease (CJD) in humans. OCT performed on the brain from a woman who died of CJD was able to detect clearly the pathological vacuoles.

Fiber Lenses for Ultra-Small Probes Used in Optical Coherent Tomography

“…For the GRIN fiber lens, the range For GRIN fiber lens, a beam profile of 15 m spot size and 1mm working distance was reported [19], although no detailed GRIN fiber and lens structure description in the paper. The 15 m spot size only could provide less than 0.3 mm depth of field in their OCT system.…”

“…In addition, a beam director can be easily attached to the fiber lenses by the fusion-splice of a polished fiber spacer for GRIN fiber lens and direct polish on the lens surface for ball fiber lens. Swanson [19], and Li et. al.…”

Optical coherence tomography as a potential readout in clinical trials

“…While the most extensive studies have been performed in MS, OCT validation as a biomarker for neurodegeneration is ongoing in each of these conditions. Alternative applications of this technology in neurologic disease have been studied in vitro, including the utilizing of an OCT probe to better position electrical leads during deep brain stimulator placement, while utilizing OCT has been recently studied to help diagnose CreutzfeldtJacob disease in vivo [Jafri et al 2005].…”

Concurrent multiscale imaging with magnetic resonance imaging and optical coherence tomography

“…3,12 However, the resolution and the contrast of MRI are not high enough to detect certain target nuclei in basal ganglia. 13 On the other hand, OCT can locate these nuclei in human brain ex vivo 14 and rat brain in vivo. 15 We place a slab of frozen human brain tissue containing basal ganglia in a gelatin holder filled with saline at room temperature and wait until it is completely thawed.…”