Laser Speckle Imaging of Cerebral Blood Flow

Richards, Lisa; Towle, Erica L.; Fox, Douglas J.; Dunn, Andrew K.

doi:10.1007/978-1-4614-4978-2_5

Cited by 4 publications

(5 citation statements)

References 42 publications

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“…The ability of the technique to measure flow velocities with high sensitivity has been confirmed by comparison to both Laser Doppler measurements [24], time of flight measurements in vivo [23], and in microfluidic systems in-vitro [25]. A number of review papers in the last few years outline the breadth of applications enabled by the technique in cortical blood flow imaging in healthy and damaged tissue [26][27][28][29].…”

Section: Introductionmentioning

confidence: 92%

Evaluation of laser speckle contrast imaging as an intrinsic method to monitor blood brain barrier integrity

Dufour¹,

Atchia²,

Gad³

et al. 2013

Biomed. Opt. Express

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The integrity of the blood brain barrier (BBB) can contribute to the development of many brain disorders. We evaluate laser speckle contrast imaging (LSCI) as an intrinsic modality for monitoring BBB disruptions through simultaneous fluorescence and LSCI with vertical cavity surface emitting lasers (VCSELs). We demonstrated that drug-induced BBB opening was associated with a relative change of the arterial and venous blood velocities. Cross-sectional flow velocity ratio (veins/arteries) decreased significantly in rats treated with BBB-opening drugs, ≤0.81 of initial values.

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Section: Introductionmentioning

confidence: 92%

Evaluation of laser speckle contrast imaging as an intrinsic method to monitor blood brain barrier integrity

Dufour¹,

Atchia²,

Gad³

et al. 2013

Biomed. Opt. Express

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“…[21][22][23][24][31][32][33] As LSCI gains popularity and clinical investigations increase, it is important to assess the impact of physiological motion and investigate methods to compensate for these artifacts. Because LSCI is inherently sensitive to motion, the recorded images are impacted by both pulsatile flow and tissue deformation from the cardiac cycle and respiration.…”

Section: Discussionmentioning

confidence: 99%

“…To account for blood flow changes that occur during the cardiac cycle, an ad hoc ECG filter [31][32][33] was implemented to reduce fluctuations in recorded τ c values. Briefly, the actual time of each image was determined from the recorded camera exposure signal and the actual time of each heartbeat was determined from the ECG waveform.…”

Section: Cardiac Filteringmentioning

confidence: 99%

Intraoperative laser speckle contrast imaging with retrospective motion correction for quantitative assessment of cerebral blood flow

et al. 2014

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Abstract. Although multiple intraoperative cerebral blood flow (CBF) monitoring techniques are currently available, a quantitative method that allows for continuous monitoring and that can be easily integrated into the surgical workflow is still needed. Laser speckle contrast imaging (LSCI) is an optical imaging technique with a high spatiotemporal resolution that has been recently demonstrated as feasible and effective for intraoperative monitoring of CBF during neurosurgical procedures. This study demonstrates the impact of retrospective motion correction on the quantitative analysis of intraoperatively acquired LSCI images. LSCI images were acquired through a surgical microscope during brain tumor resection procedures from 10 patients under baseline conditions and after a cortical stimulation in three of those patients. The patient's electrocardiogram (ECG) was recorded during acquisition for postprocess correction of pulsatile artifacts. Automatic image registration was retrospectively performed to correct for tissue motion artifacts, and the performance of rigid and nonrigid transformations was compared. In baseline cases, the original images had 25% AE 27% noise across 16 regions of interest (ROIs). ECG filtering moderately reduced the noise to 20% AE 21%, while image registration resulted in a further noise reduction of 15% AE 4%. Combined ECG filtering and image registration significantly reduced the noise to 6.2% AE 2.6% (p < 0.05). Using the combined motion correction, accuracy and sensitivity to small changes in CBF were improved in cortical stimulation cases. There was also excellent agreement between rigid and nonrigid registration methods (15/16 ROIs with <3% difference). Results from this study demonstrate the importance of motion correction for improved visualization of CBF changes in clinical LSCI images. © The Authors.Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…7 Registered images were selected from the same 0.2-s normalized time window of the cardiac cycle to synchronize with the heartbeat and minimize pulsatile variation across exposure times. 6,7,19 Fifty images spanning multiple heartbeats were averaged for each exposure time to reduce noise for the computation of MESI ICT maps. A sub-set of recorded images (20–30 s, 1400–2000 frames) from each exposure time was used for analysis on select regions of interest (ROIs), which were cardiac filtered similar to previous work.…”

Section: Methodsmentioning

confidence: 99%

“…A sub-set of recorded images (20–30 s, 1400–2000 frames) from each exposure time was used for analysis on select regions of interest (ROIs), which were cardiac filtered similar to previous work. 6,7,19 ICT values were computed and displayed as summary values, since each exposure corresponded to different time points. For the single-exposure LSCI recording during tissue cautery in case 8, ROI data were cardiac filtered, smoothed using a 0.5-s moving average filter, and displayed as a time course.…”

Section: Methodsmentioning

confidence: 99%

Intraoperative multi-exposure speckle imaging of cerebral blood flow

Richards

Kazmi

Olin

et al. 2017

J Cereb Blood Flow Metab

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Multiple studies have demonstrated that laser speckle contrast imaging (LSCI) has high potential to be a valuable cerebral blood flow monitoring technique during neurosurgery. However, the quantitative accuracy and sensitivity of LSCI is limited, and highly dependent on the exposure time. An extension to LSCI called multi-exposure speckle imaging (MESI) overcomes these limitations, and was evaluated intraoperatively in patients undergoing brain tumor resection. This clinical study ( n = 8) recorded multiple exposure times from the same cortical tissue area spanning 0.5-20 ms, and evaluated images individually as single-exposure LSCI and jointly using the MESI model. This study demonstrated that the MESI estimates provided the broadest flow sensitivity for sampling the flow magnitude in the human brain, closely followed by the shorter exposure times. Conservation of flow analysis on vascular bifurcations was used to validate physiological accuracy, with highly conserved flow estimates (<10%) from both MESI and 1 ms LSCI ( n = 14 branches). The MESI model had high goodness-of-fit with proper image calibration and acquisition, and was used to monitor blood flow changes after tissue cautery. Results from this study demonstrate that intraoperative MESI can be performed with high quantitative accuracy and sensitivity for cerebral blood flow monitoring.

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Laser Speckle Imaging of Cerebral Blood Flow

Cited by 4 publications

References 42 publications

Evaluation of laser speckle contrast imaging as an intrinsic method to monitor blood brain barrier integrity

Evaluation of laser speckle contrast imaging as an intrinsic method to monitor blood brain barrier integrity

Intraoperative laser speckle contrast imaging with retrospective motion correction for quantitative assessment of cerebral blood flow

Intraoperative multi-exposure speckle imaging of cerebral blood flow

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