Combined laser Doppler and laser speckle imaging for real-time blood flow measurements

2006 ◽  
Author(s):  
Alexandre Serov ◽  
Theo Lasser
Keyword(s):  
Blood Flow ◽  
Real Time ◽  
Laser Speckle ◽  
Laser Doppler ◽  
Laser Speckle Imaging ◽  
Speckle Imaging ◽  
Flow Measurements ◽  
Blood Flow Measurements

Dilated Residual Learning With Skip Connections for Real-Time Denoising of Laser Speckle Imaging of Blood Flow in a Log-Transformed Domain

2020 ◽  
Vol 39 (5) ◽  
pp. 1582-1593
Author(s):  
Weimin Cheng ◽  
Jinling Lu ◽  
Xuan Zhu ◽  
Jiachi Hong ◽  
Xiaohu Liu ◽  
...  
Keyword(s):  
Blood Flow ◽  
Real Time ◽  
Laser Speckle ◽  
Laser Speckle Imaging ◽  
Speckle Imaging ◽  
Residual Learning

scholarly journals Laser Speckle Imaging Allows Real-Time Intraoperative Blood Flow Assessment During Neurosurgical Procedures

2013 ◽  
Vol 33 (7) ◽  
pp. 1000-1007 ◽  
Author(s):  
Nils Hecht ◽  
Johannes Woitzik ◽  
Susanne König ◽  
Peter Horn ◽  
Peter Vajkoczy
Keyword(s):  
Blood Flow ◽  
Real Time ◽  
Bypass Graft ◽  
Laser Speckle ◽  
Neurosurgical Procedures ◽  
Laser Speckle Imaging ◽  
Speckle Imaging ◽  
Intracranial Surgery ◽  
Hemodynamic Compromise ◽  
Real Time Visualization

Currently, there is no adequate technique for intraoperative monitoring of cerebral blood flow (CBF). To evaluate laser speckle imaging (LSI) for assessment of relative CBF, LSI was performed in 30 patients who underwent direct surgical revascularization for treatment of arteriosclerotic cerebrovascular disease (ACVD), Moyamoya disease (MMD), or giant aneurysms, and in 8 control patients who underwent intracranial surgery for reasons other than hemodynamic compromise. The applicability and sensitivity of LSI was investigated through baseline perfusion and CO2 reactivity testing. The dynamics of LSI were assessed during bypass test occlusion and flow initiation procedures. Laser speckle imaging permitted robust (pseudo-) quantitative assessment of relative microcirculatory flow and standard bypass grafting resulted in significantly higher postoperative baseline perfusion values in ACVD and MMD. The applicability and sensitivity of LSI was shown by a significantly reduced CO2 reactivity in ACVD (9.6 ± 9%) and MMD (8.5 ± 8%) compared with control (31.2 ± 5%; P < 0.0001). In high- and intermediate-flow bypass patients, LSI was characterized by a dynamic real-time response to acute perfusion changes and ultimately confirmed a sufficient flow substitution through the bypass graft. Thus, LSI can be used for sensitive and continuous, non-invasive real-time visualization and measurement of relative cortical CBF in excellent spatial-temporal resolution.

scholarly journals Infarct prediction by intraoperative laser speckle imaging in patients with malignant hemispheric stroke

2015 ◽  
Vol 36 (6) ◽  
pp. 1022-1032 ◽  
Author(s):  
Nils Hecht ◽  
Marc-Michael Müller ◽  
Nora Sandow ◽  
Alexandra Pinczolits ◽  
Peter Vajkoczy ◽  
...  
Keyword(s):  
Blood Flow ◽  
Human Brain ◽  
Real Time ◽  
Three Dimensional ◽  
Laser Speckle ◽  
Laser Speckle Imaging ◽  
Speckle Imaging ◽  
Hemispheric Stroke ◽  
Postoperative Mri ◽  
Cortical Ischemia

Currently, a reliable method for real-time prediction of ischemia in the human brain is not available. Here, we took a first step towards validating non-invasive intraoperative laser speckle imaging (iLSI) for prediction of infarction in 22 patients undergoing decompressive surgery for treatment of malignant hemispheric stroke. During surgery, cortical perfusion was visualized and recorded in real-time with iLSI. The true morphological infarct extension within the iLSI imaging field was superimposed onto the iLSI blood flow maps according to a postoperative MRI (16 h [95% CI: 13, 19] after surgery) with three-dimensional magnetization-prepared rapid gradient-echo and diffusion-weighted imaging reconstruction. Based on the frequency distribution of iLSI perfusion values within the infarcted and non-infarcted territories, probability curves and perfusion thresholds of normalized cerebral blood flow predictive of eventual infarction or non-infarction were calculated. Intraoperative LSI predicted and excluded cortical ischemia with 95% probability at normalized perfusion levels below 40% and above 110%, respectively, which represented 73% of the entire cortical surface area. Together, our results suggest that iLSI is valid for (pseudo-) quantitative assessment of blood flow in the human brain and may be used to identify tissue at risk for infarction at a given time-point in the course of ischemic stroke.

Hybrid blood flow probe for simultaneous H2 clearance and laser-Doppler velocimetry

1987 ◽  
Vol 253 (4) ◽  
pp. G573-G581 ◽  
Author(s):  
G. R. DiResta ◽  
J. W. Kiel ◽  
G. L. Riedel ◽  
P. Kaplan ◽  
A. P. Shepherd
Keyword(s):  
Blood Flow ◽  
Laser Doppler Velocimetry ◽  
Regional Blood Flow ◽  
Laser Doppler ◽  
Doppler Velocimetry ◽  
Flow Probe ◽  
Flow Measurements ◽  
Blood Flow Measurements ◽  
Light Guides ◽  
The Relationship

To perform two independent regional blood flow measurements in tissue volumes of similar dimensions, we designed a hybrid blood flow probe capable of measuring regional perfusion by both laser-Doppler velocimetry (LDV) and H2 clearance. The probe consisted of two fiber-optic light guides to conduct light between the surface of tissue of interest and a laser-Doppler blood flowmeter. Also contained within the probe were a platinum 25-microns H2-sensing electrode and a 125-microns H2-generating electrode. The probe can thus be used to measure local perfusion with H2 clearance. The H2 can either be inhaled or can be generated electrochemically at the locus of interest. Evaluation of the probe in the canine gastric mucosa indicated 1) that the relationship between mucosal flow measurements made simultaneously with H2 clearance and LDV was highly significant and linear and 2) that H2 clearance could potentially be used to calibrate the laser-Doppler blood flowmeter in absolute units. The methods of constructing the flow probes are discussed in detail.

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