Congratulations to Chia-Pin Liang From the University of Maryland a Winner of a 2012 Student Travel Grant Award
Stereotactic procedures that require insertion of needle-based instruments into the brain serve important roles in a variety of neurosurgical interventions such as biopsy, catheterization, and electrode placement. The laceration of blood vessels in the path of the advancing needle can result in stroke and even death and is perhaps the most worried complication. Also, the brain may shift during surgery because of cerebrospinal fluid (CSF) leakage so that the intended target is no longer positioned at the pre-operatively (MRI or CT) determined coordinates. A forward-imaging OCT probe that can detect the at-risk blood vessels, provide micro-anatomical images, and fit into current surgical instruments (I.D. ~1mm) has great potential to overcome these limitations. Although many forward-imaging OCT probes have been demonstrated, developing an effective imaging probe with needle-like geometry (O.D. < 1 mm), forward-imaging capability, and Doppler OCT (DOCT) capability to detect blood vessels is still an unmet challenge. In this study, we demonstrate that a GRIN-rod-lens (O.D. = 0.5 mm) design can fulfill these requirements. The stationary GRIN-rod-lens provides sensitive vessel detection via DOCT with 41 dB velocity dynamic range (VDR) and ±17 um/s velocity resolution. The forward-imaging OCT needle probe also provide real-time (100 frames/s in OCT mode, 8 frame/s in OCT/DOCT dual mode), high resolution (13 um) and high-sensitivity (>90 dB) imaging guidance for neurosurgery. The effectiveness and robustness of the system were demonstrated in in vivo sheep brains, in vivo rat femoral vessels, and ex vivo human brains.