A forward-imaging needle-type OCT probe for image guided stereotactic procedures

Abstract

A forward-imaging needle-type optical coherence tomography (OCT) probe with Doppler OCT (DOCT) capability has the potential to solve critical challenges in interventional procedures. A case in point is stereotactic neurosurgery where probes are advanced into the brain based on predetermined coordinates. Laceration of blood vessels in front of the advancing probe is an unavoidable complication with current methods. Moreover, cerebrospinal fluid (CSF) leakage during surgery can shift the brain rendering the predetermined coordinates unreliable. In order to address these challenges, we developed a forward-imaging OCT probe (740 μm O.D.) using a gradient-index (GRIN) rod lens that can provide real-time imaging feedback for avoiding at-risk vessels (8 frames/s with 1024 A-scans per frame for OCT/DOCT dual imaging) and guiding the instrument to specific targets with 12 μm axial resolution (100 frames/s with 160 A-scans per frame for OCT imaging only). The high signal-to-background characteristic of DOCT provides exceptional sensitivity in detecting and quantifying the blood flow within the sheep brain parenchyma in real time. The OCT/DOCT dual imaging also demonstrated its capability to differentiate the vessel type (artery/vein) on rat's femoral vessels. We also demonstrated in ex vivo human brain that the location of the tip of the OCT probe can be inferred from micro-anatomical landmarks in OCT images. These findings demonstrate the suitability of OCT guidance during stereotactic procedures in the brain and its potential for reducing the risk of cerebral hemorrhage.

High-dynamic-range fluorescence laminar optical tomography (HDR-FLOT)

“…The OCT system shown in Fig. 1(B) was described previously [7,[26][27][28]. A wavelength-swept laser centered at 1310 nm with a 100-nm bandwidth was used in this frequency-domain OCT system as a light source [7,26,27].…”

“…The wavelength-swept frequency was 16 kHz and the output power from the laser was approximately 16 mW. About 97% of the laser power was split 50:50 to the sample and the reference arms of a fiber-based Michelson interferometer [7,26,27]. A balanced detector (BD) was used to receive the interference fringes from different depths encoded with different frequencies.…”

Review of intraoperative optical coherence tomography: technology and applications [Invited]

“…In 2011 a probe incorporating galvanometer scanners and GRIN lens-based relays was reported for stereotactic neurosurgery procedures, in which deep-brain tissues are accessed using long cannulas [99]. The needle probe was 0.74 mm in diameter and could be inserted into cannulas to image structures up to 9.5 cm deep into brain tissue.…”

Optical coherence tomography for precision brain imaging, neurosurgical guidance and minimally invasive theranostics

“…For giving an intuitive view of brain tissue, some researchers have designed and manufactured a neurosurgical probe of OCT, including endoscopic, needle-type, hand-held probe, and other kinds of neurosurgical OCT robotic arms (68,(72)(73)(74)(75)(76)(77)(78)(79) intrinsic brain tumors (68). In microsurgery, Kang et al proposed a common-path OCT system with an applicable fiber-optic endoscopic probe (74,76).…”

“…Furthermore, a hand-held forward-viewing probe is useful for neurosurgical imaging and residual tumor detection due to the irregular and limited resection cavity. Liang et al and Sun et al developed a needletype forward-imaging OCT probe, which was fit for minimally invasive tools (77)(78)(79).…”