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Abstract
Introduction Diffuse correlation spectroscopy (DCS) is a noninvasive optical technique that enables continuous measurements of blood flow in various organs, including the brain. DCS measures blood flow from temporal fluctuations in intensity of diffusely reflected light that has interacted with moving red blood cells within the tissue. We present our initial experience on the use of DCS in conjunction with acute neuroendovascular interventions for ischemic stroke and discuss potential rational for utilization and clinical relevance of DCS-generated data.
Methods The DCS instrument comprises of long coherence length lasers and single photon counting detectors, which are connected to the measurement site on the patient via inert fiber optic probes. Once consent for participation was obtained, the probes were applied, and experimental data, clinical and imaging data were collected prospectively. Cerebral blood flow (CBF) optical measurements were collected from probes applied to the temporal and frontal regions matching the standard locations for transtemporal (MCA territory) and transorbital (ACA territory) acoustic windows for insonation. Baseline and follow-up demographic, imaging and clinical data, stroke severity on admission and during hospitalization was recorded prospectively per study protocol.
Results The device was successfully applied in 12 subjects. There were no safety concerns or interference with the standard angiography suite or intensive care unit workflow. In 3 cases, subsequent DCS data processing revealed that contact probe recordings were compromised due to lead malfunction, making these data non-diagnostic. 7 cases were selected for final analysis and interpretation. Depending on type of the case, either continuous recordings (10-15 minutes in length) or intermittent recordings (60-120 seconds in length) were obtained from bilateral temporal and/or frontal regions. DCS measurements with photon count rates greater than 30 KHz had sufficient signal-to-noise to resolve blood flow pulsatility. We found an association between angiographic changes in cerebral reperfusion (established partial or complete reperfusion in stroke thrombectomy cases; temporary flow arrest during carotid artery stenting) observed intraprocedurally with CBF measurements. Limitations of the current technology included sensitivity to the interrogated tissue volume under the probe and the effect of local changes in tissue optical properties on the accuracy of CBF estimates.
Conclusions We showed the feasibility of this non-invasive approach in providing continuous measurement of regional CBF brain tissue properties. In the future, implementations of more robust DCS instruments such as our recently developed pathlength-resolved DCS device could alleviate the limitations of the current DCS technology discovered during this study.
Disclosures M. Mokin: 1; C; NIH NINDS. 2; C; Cerenovus, Medtronic. 4; C; Bendit Technologies, Borvo medical, BrainQ, Endostream, Serenity medical, Synchron, Sim&Cure, QAS.AI, Quantanosis.AI. S. Thanki: None. P. Mohammad: None. S. Sheehy: None. K. Jones: None. I. Peto: None. W. Guerrero: None. K. Vakharia: None. W. Burgin: None. A. Parthasarathy: 1; C; NIH NINDS.