Laser Speckle Contrast Imaging Data Research Articles

Association of Speckle-Based Blood Flow Measurements and Fluorescein Angiography in Infants with Retinopathy of Prematurity

PurposeTo determine the correlation between blood flow metrics measured by intravenous fluorescein angiography (IVFA) and blood flow velocity index (BFVi) obtained by laser speckle contrast imaging (LSCI) in infants with retinopathy of prematurity (ROP). DesignProspective comparative pilot study. SubjectsSeven eyes from seven subjects with ROP. MethodsUnilateral LSCI and IVFA data was obtained from each subject in the neonatal intensive care unit (NICU). Five LSCI-based metrics and five IVFA-based metrics were extracted from images to quantify blood flow patterns in the same region of interest. Correlation between LSCI-based and IVFA-based blood flow metrics was compared between two subgroups of ROP severity: moderate ROP (defined as stage ≤2 without Plus disease) and severe ROP (defined as stage ≥3 or Plus disease). Main Outcome MeasuresPearson and Kendall’s Rank correlation coefficients between IVFA and LSCI metrics; Student’s t test p values comparing LSCI metrics between “severe” and “moderate” ROP groups. ResultsPearson’s correlations between IVFA and LSCI included arterial-venous transit time (AVTT) and peak BFVi (r = -0.917, p = 0.004), AVTT and dip BFVi (r = -0.920, p = 0.003), AVTT and mean BFVi (r = -0.927, p = 0.003), and AVTT and volumetric rise index (r = -0.779, p = 0.039). Kendall’s Rank correlation between AVTT and dBFVi was r = -0.619 (p = 0.051). Peak BFVi was higher in severe ROP than in moderate ROP (8.4 ± 0.6 and 4.4 ± 1.8 respectively, p = 0.0045 using 2-sample t-test with pooled variance, and p = 0.0952 using Wilcoxon rank-sum test). ConclusionCorrelation was found between blood flow metrics obtained by IVFA and noninvasive LSCI techniques. We demonstrate the feasibility of obtaining quantitative metrics using LSCI in infants with ROP in this pilot study, but further investigation is needed to evaluate its potential use in clinical assessment of ROP severity.

Choosing a polarisation configuration for dynamic light scattering and laser speckle contrast imaging.

Laser speckle contrast imaging (LSCI) is applied in various biomedical applications for full-field characterization of blood flow and tissue perfusion. The accuracy of the contrast interpretation and its conversion to the blood flow index depends on specific parameters of the optical system and scattering media. One such parameter is the polarisation of detected light, which is often adjusted to minimize specular reflections and image artefacts. The polarisation's effect on the detected light scattering dynamics and, therefore, the accuracy of LSCI data interpretation requires more detailed investigation. In this study, we used LSCI and Dynamic Light Scattering Imaging to evaluate the effects of the detected light polarisation when imaging perfusion in the mouse cortex. We found that cross-polarisation results in a shorter decorrelation time constant, a higher coherence degree and stronger dynamic scattering compared to the parallel-polarisation or no-polariser configurations. These results support the cross-polarisation configuration as the most optimal for brain cortex imaging and suggest against direct or calibrated comparisons between the contrast recordings made with different polarisation configurations.

In vivo laser speckle contrast imaging of 4-aminopyridine- or pentylenetetrazole-induced seizures.

Clinical and preclinical studies on epileptic seizures are closely linked to the study of neurovascular coupling. Obtaining reliable information about cerebral blood flow (CBF) in the area of epileptic activity through minimally invasive techniques is crucial for research in this field. In our studies, we used laser speckle contrast imaging (LSCI) to gather information about the local blood circulation in the area of epileptic activity. We used two models of epileptic seizures: one based on 4-aminopyridine (4-AP) and another based on pentylenetetrazole (PTZ). We verified the duration of an epileptic seizure using electrocorticography (ECoG). We applied the antiepileptic drug topiramate (TPM) to both models, but its effect was different in each case. However, in both models, TPM had an effect on neurovascular coupling in the area of epileptic activity, as shown by both LSCI and ECoG data. We demonstrated that TPM significantly reduced the amplitude of 4-AP-induced epileptic seizures (4-AP+TPM: 0.61 ± 0.13 mV vs 4-AP: 1.08 ± 0.19 mV; p < 0.05), and it also reduced gamma power in ECoG in PTZ-induced epileptic seizures (PTZ+TPM: 38.5% ± 11.9% of the peak value vs PTZ: 59.2% ± 3.0% of peak value; p < 0.05). We also captured the pattern of CBF changes during focal epileptic seizures induced by 4-AP. Our data confirm that the system of simultaneous cortical LSCI and registration of ECoG makes it possible to evaluate the effectiveness of pharmacological agents in various types of epileptic seizures in in vivo models and provides spatial and temporal information on the process of ictogenesis.

Smartphone-Based Rigid Endoscopy Device with Hemodynamic Response Imaging and Laser Speckle Contrast Imaging.

Modern smartphones have been employed as key elements in point-of-care (POC) devices due to remarkable advances in their form factor, computing, and display performances. Recently, we reported a combination of the smartphone with a handheld endoscope using laser speckle contrast imaging (LSCI), suggesting potential for functional POC endoscopy. Here, we extended our work to develop a smartphone-combined multifunctional handheld endoscope using dual-wavelength LSCI. Dual-wavelength LSCI is used to monitor the changes in dynamic blood flow as well as changes in the concentration of oxygenated (HbO2), deoxygenated (Hbr), and total hemoglobin (HbT). The smartphone in the device performs fast acquisition and computation of the raw LSCI data to map the blood perfusion parameters. The flow imaging performance of the proposed device was tested with a tissue-like flow phantom, exhibiting a speckle flow index map representing the blood perfusion. Furthermore, the device was employed to assess the blood perfusion status from an exteriorized intestine model of rat in vivo during and after local ischemia, showing that blood flow and HbO2 gradually decreased in the ischemic region whereas hyperemia and excess increases in HbO2 were observed in the same region right after reperfusion. The results indicate that the combination of LSCI with smartphone endoscopy delivers a valuable platform for better understanding of the functional hemodynamic changes in the vasculatures of the internal organs, which may benefit POC testing for diagnosis and treatment of vascular diseases.

Semi-Automatic Tracking of Laser Speckle Contrast Images of Microcirculation in Diabetic Foot Ulcers

Foot ulcers are a severe complication of diabetes mellitus. Assessment of the vascular status of diabetic foot ulcers with Laser Speckle Contrast Imaging (LSCI) is a promising approach for diagnosis and prognosis. However, manual assessment during analysis of LSCI limits clinical applicability. Our aim was to develop and validate a fast and robust tracking algorithm for semi-automatic analysis of LSCI data. The feet of 33 participants with diabetic foot ulcers were recorded with LSCI, including at baseline, during the Post-Occlusive Reactive Hyperemia (PORH) test, and during the Buerger’s test. Different regions of interest (ROIs) were used to measure microcirculation in different areas of the foot. A tracking algorithm was developed in MATLAB to reposition the ROIs in the LSCI scans. Manual- and algorithm-tracking of all recordings were compared by calculating the Intraclass Correlation Coefficient (ICC). The algorithm was faster in comparison with the manual approach (90 s vs. 15 min). Agreement between manual- and algorithm-tracking was good to excellent during baseline (ICC = 0.896–0.984; p < 0.001), the PORH test (ICC = 0.790–0.960; p < 0.001), and the Buerger’s test (ICC = 0.851–0.978; p < 0.001), resulting in a tracking algorithm that delivers assessment of LSCI in diabetic foot ulcers with results comparable to a labor-intensive manual approach, but with a 10-fold workload reduction.

Local Heating Mediated Vasodilation Increased 48 Hours After Remote Ischemic Preconditioning

IntroductionRemote ischemic preconditioning (RIPC), induced by brief periods of blood flow occlusion to a limb followed by reperfusion, protects distant tissues from ischemia‐reperfusion (IR) injury. A single bout of RIPC confers a delayed window of protection that begins 24 hrs after RIPC and last for 2–3 days; however, whether this timeline also applies to the microvasculature is unclear. We hypothesize that the hyperemic response to local heating will increase after a single bout of RIPC.MethodsSixteen healthy, young adults (7M, 9F) underwent a single session of RIPC, which consisted of four periods of inflating an arm cuff to 200mmHg for five min interspersed with five min of reperfusion. Laser speckle contrast imaging (LSCI) was used to measure the hyperemia response to local skin heating (Tsk = 42°C) at five time points; before treatment, and 24, 48, 72, and 168 hrs post‐RIPC. LSCI data are expressed as cutaneous vascular conductance (CVC = LSCI flux/mean arterial pressure).ResultsCompared to pre‐RIPC (1.58 ± 0.09 flux · mmHg−1), the vasodilation response to local heating was increased only at the 48‐hr post‐RIPC time point (24 hrs: 1.59 ± 0.10, 48 hrs: 1.69 ± 0.10, 72 hrs: 1.54 ± 0.13, 160 hrs: 1.53 ± 0.11 flux · mmHg−1).ConclusionThese results indicate that the modest increase in local‐mediation dilation exhibited a delayed response that peaked 48 hrs following a single RIPC bout. This suggests that a single bout of RIPC may have a protective effect on the microvasculature.Support or Funding InformationNASA – Iowa Space Consortium Grant

642 The Use of Laser Speckle Contrast Imaging in Assessing Depth and Progression of Burn Wounds

Abstract Introduction The ability of laser speckle contrast imaging (LSCI) to provide real-time images of blood flow makes this modality appealing in the assessment of burn wounds, particularly for clinicians making treatment decisions based on burn wound depth and presumed progression. Here we present 2 preclinical studies that used LSCI to assess wound progress, both immediately and months after injury. Methods LSCI images were taken 10-40cm away from the wound and captured with a 1388x1038-pixel CCD camera. In the first study, LSCI images were captured prior to and immediately following creation of superficial partial-thickness (SPTB, 10s), deep partial-thickness (DPTB, 15s), and full-thickness burns (FTB, 20s), and on post-burn day (PBD) 1, 2, and 3. In the second study, LSCI images were obtained before and after DPTB creation and on PBD 7, 14, 21, 28, 60, 90, and 120. Results 92 wounds from 9 swine were included. Speckle data was normalized to control sites and converted to percentages ([speckle wound/speckle control] x 100), producing speckle percentage of control (SPOC) which quantifies the relative decrease or increase in speckle output (vascularity). SPOC was significantly decreased for all burn times on PBD 0, 1, and 2. By PBD 3, only DPTB and FTB remained diminished (p=0.028 and p=0.005, respectively), and FTB SPOC was significantly less than the SPTB (p=0.015). In the second study, SPOC showed an increase post-debridement on PBD 7, noted as post-debridement day (PDD) 0. SPOC continued to increase significantly to a peak at PDD 7 (p&amp;lt; 0.0001) and remained elevated until PDD 28. By PDD 60, SPOC was no longer significantly increased. Conclusions LSCI is a reliable method for analyzing burn depth and wound progression in the preclinical setting. LSCI data shows an immediate decrease in vascularity at all burn depths immediately following burn creation, followed by a peak in vascularity on PDD 7, with a trend back to normal by PDD 60. Applicability of Research to Practice The correlation of wound bed vascularity based on LSCI to known data on burn depth and progression suggests that LSCI could be a useful measurement tool in the clinical setting for the provider determining wound viability.

Data compression and improved registration for laser speckle contrast imaging of rodent brains.

Single-frame blood flow maps from laser speckle contrast imaging (LSCI) contain high spatiotemporal variation that obscures high spatial-frequency vascular features, making precise image registration for signal amplification challenging. In this work, novel bivariate standardized moment filters (BSMFs) were used to provide stable measures of vessel edge location, permitting more robust LSCI registration. Relatedly, BSMFs enabled the stable reconstruction of vessel edges from sparsely distributed blood flow map outliers, which were found to retain most of the temporal dynamics. Consequently, data discarding and BSMF-based reconstruction enable efficient real-time quantitative LSCI data compression. Smaller LSCI-kernels produced log-normal blood flow distributions, enhancing sparse-to-dense inference.

Multiscale Poincaré plot analysis of time series from laser speckle contrast imaging data

The monitoring of microvascular blood flow is of importance for research and clinical purposes because, for some pathologies as diabetes, the microcirculation may be affected long before organ dysfunctions are diagnosed. Laser speckle contrast imaging (LSCI) is gaining an increased interest to monitor microvascular blood flow (peripheral cardiovascular data). However, in spite of this and by opposition to central cardiovascular data as electrocardiograms, very few studies have been conducted on the analysis of LSCI through scales. We therefore propose to process LSCI data with a multiscale approach relying on Poincare plots. For this purpose, we first study multiscale Poincare (MSP) plots of simulated signals (synthetic white and 1/f noise time series). Then, MSP plots of LSCI time series recorded in 24 healthy volunteers are generated and analyzed. Furthermore, this analysis on real-life data is also conducted to study the role played by age on the results. Thus, the subjects were divided into two age groups: 13 young subjects (mean age = 23.8 ± 3.2 years old) and 11 elderly subjects (mean age = 56.9 ± 6.7 years old). Our results show properties that may reveal a weak fractal structure for LSCI data. Moreover, we find no statistical difference (p ≥ 0.05) for the descriptors of MSP plots between the two age groups. MSP plots may become a simple-to-implement visualization tool to provide new insights into biomedical data across scales.

Bi-dimensional variational mode decomposition of laser speckle contrast imaging data: A clinical approach to critical limb ischemia?

The number of patients suffering from peripheral arterial occlusive disease (PAOD) is growing worldwide. PAOD corresponds to an impairment of perfusion in the distal portion of some arteries that can generate critical limb ischemia. For some patients, the pathology leads to the necessity of amputation. PAOD may be diagnosed and studied with transcutaneous oxygen (tcpO2) measurements. However, the tcpO2 technique is a contact technique: probes have to be positioned on the limb, which may be impossible in case of ulcers and can lead to infection risks. We therefore herein propose to study if the laser speckle contrast imaging (LSCI) technique, an optical contactless technique, could be of interest in studying limb ischemia. For this purpose, tcpO2 and LSCI data were recorded in 48 persons suffering or not from PAOD (different levels of criticality). The LSCI data were then processed with the recently introduced bi-dimensional variational mode decomposition (2D–VMD). 2D–VMD leads to band-limited intrinsic mode functions (LSCI 2D–BLIMFs in our case). From these LSCI 2D–BLIMFs, we propose a new index. Our results show that this index and the tcpO2 values have a Pearson's r correlation coefficient of −0.401. Moreover, the Bland-Altman graph shows that the LSCI 2D–BLIMFs-based index and the tcpO2 values are consistent. LSCI might therefore be of interest for a contactless study of limb ischemia.

Bidimensional unconstrained optimization approach to EMD: An algorithm revealing skin perfusion alterations in pseudoxanthoma elasticum patients

Background and Objective: Pseudoxanthoma elasticum (PXE) is an inherited and systemic metabolic disorder that affects the skin, leading among other things to a peau d’orange appearance. Unfortunately, PXE is still poorly understood and there is no existing therapy to treat the disease. Because the skin is the first organ to be affected in PXE, we propose herein a study of skin microvascular perfusion. By means of this analysis, our goal is to increase knowledge of PXE. Methods: For this purpose, microvascular data from patients suffering from PXE and from healthy control subjects were recorded using the laser speckle contrast imaging (LSCI) modality. These data were processed using the recent 2D version of the unconstrained optimization approach to empirical mode decomposition (UOA-EMD). Our work therefore corresponds to the first time this algorithm has been applied to biomedical data. Results: Our study shows that the 2D-UOA-EMD is able to reveal spatial patterns on local textures of LSCI data. Moreover, these spatial patterns differ between PXE patients and control subjects. Quantification measure of these spatial patterns reveals statistical significant differences between PXE and control subjects, in the neck (p=0.0004) and in the back (p=0.0052). Conclusions: For the first time, alterations in microvascular perfusion in PXE patients have been revealed. Our findings open new avenues for our understanding of pathophysiologic skin changes in PXE.

Combined effects of scattering and absorption on laser speckle contrast imaging.

Several variables may affect the local contrast values in laser speckle contrast imaging (LSCI), irrespective of relative motion. It has been suggested that the optical properties of the moving fluid and surrounding tissues can affect LSCI values. However, a detailed study of this has yet to be presented. In this work, we examined the combined effects of the reduced scattering and absorption coefficients on LSCI. This study employs fluid phantoms with different optical properties that were developed to mimic whole blood with varying hematocrit levels. These flow phantoms were imaged with an LSCI system developed for this study. The only variable parameter was the optical properties of the flowing fluid. A negative linear relationship was seen between the changes in contrast and changes in reduced scattering coefficient, absorption coefficient, and total attenuation coefficient. The change in contrast observed due to an increase in the scattering coefficient was greater than what was observed with an increase in the absorption coefficient. The results indicate that optical properties affect contrast values and that they should be considered in the interpretation of LSCI data.

Visualization of perfusion changes with laser speckle contrast imaging using the method of motion history image

Laser speckle contrast imaging (LSCI) is a real-time imaging modality reflecting microvascular perfusion. We report on the application of the motion history image (MHI) method on LSCI data obtained from the two hemispheres of a mouse. Through the generation of a single image, MHI stresses the microvascular perfusion changes. Our experimental results performed during a pinprick-triggered spreading depolarization demonstrate the effectiveness of MHI: MHI allows the visualization of perfusion changes without loss of resolution and definition. Moreover, MHI provides close results to the ones given by the generalized differences (GD) algorithm. However, MHI has the advantage of giving information on the temporal evolution of the perfusion variations, which GD does not.

Multi-dimensional complete ensemble empirical mode decomposition with adaptive noise applied to laser speckle contrast images.

Laser speckle contrast imaging (LSCI) is a noninvasive full-field optical technique which allows analyzing the dynamics of microvascular blood flow. LSCI has attracted attention because it is able to image blood flow in different kinds of tissue with high spatial and temporal resolutions. Additionally, it is simple and necessitates low-cost devices. However, the physiological information that can be extracted directly from the images is not completely determined yet. In this work, a novel multi-dimensional complete ensemble empirical mode decomposition with adaptive noise (MCEEMDAN) is introduced and applied in LSCI data recorded in three physiological conditions (rest, vascular occlusion and post-occlusive reactive hyperaemia). MCEEMDAN relies on the improved complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and our algorithm is specifically designed to analyze multi-dimensional data (such as images). Over the recent multi-dimensional ensemble empirical mode decomposition (MEEMD), MCEEMDAN has the advantage of leading to an exact reconstruction of the original data. The results show that MCEEMDAN leads to intrinsic mode functions and residue that reveal hidden patterns in LSCI data. Moreover, these patterns differ with physiological states. MCEEMDAN appears as a promising way to extract features in LSCI data for an improvement of the image understanding.

Analysis of laser speckle contrast images variability using a novel empirical mode decomposition: comparison of results with laser Doppler flowmetry signals variability.

Laser Doppler flowmetry (LDF) and laser speckle contrast imaging (LSCI) have emerged as noninvasive optical modalities to monitor microvascular blood flow. Many studies proposed to extract physiological information from LDF by analyzing signals variability. By opposition, such analyses for LSCI data have not been conducted yet. We propose to analyze LSCI variability using a novel data-driven method: the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN). CEEMDAN is suitable for nonlinear and nonstationary data and leads to intrinsic mode functions (IMFs). It is based on the ensemble empirical mode decomposition (EEMD) which relies on empirical mode decomposition (EMD). In our work the average frequencies of LSCI IMFs given by CEEMDAN are compared with the ones given by EMD and EEMD. Moreover, LDF signals acquired simultaneously to LSCI data are also processed with CEEMDAN, EMD and EEMD. We show that the average frequencies of IMFs given by CEEMDAN depend on the signal-to-noise ratio (SNR) used in the computation but, for a given SNR, the average frequencies found for LSCI are close to the ones obtained for LDF. By opposition, EEMD leads to IMFs with frequencies that do not vary much when the SNR level is higher than a threshold. The new CEEMDAN algorithm has the advantage of achieving a complete decomposition with no error in the reconstruction but our study suggests that further work is needed to gain knowledge in the adjustment of the added noise level. CEEMDAN, EMD and EEMD are data-driven methods that can provide a better knowledge of LSCI.

Linguistic Analysis of Laser Speckle Contrast Images Recorded at Rest and During Biological Zero: Comparison With Laser Doppler Flowmetry Data

Laser speckle contrast imaging (LSCI) is a newly commercialized imaging modality to monitor microvascular blood flow. Contrary to the well-known laser Doppler flowmetry (LDF), LSCI has the advantage of giving a full-field image of surface blood flow using simple instrumentation. However, laser speckle contrast images are not fully understood yet and their link with LDF signals still has to be studied. To quantify the similarity between LSCI and LDF symbolic sequences, we propose to use, for the first time, the index adapted from linguistic analysis and information theory proposed by Yang For this purpose, LSCI and LDF data were recorded simultaneously on the forearm of healthy subjects, at rest and during a vascular occlusion (biological zero). We show that there are different dynamical patterns for LSCI and LDF data, and the distances between these patterns differ through the space scales explored. Moreover, our results suggest that these different dynamical patterns could be linked to blood flow. The quantitative metric used herein therefore provides new information on LSCI and brings knowledge on links between LSCI and LDF.

Blood Perfusion Values of Laser Speckle Contrast Imaging and Laser Doppler Flowmetry: Is a Direct Comparison Possible?

Laser Doppler flowmetry (LDF) and laser speckle contrast imaging (LSCI) allow the monitoring of microvascular blood perfusion. The relationship between the measurements obtained by these two techniques remains unclear. In the present contribution, we demonstrate, experimentally and theoretically, that skin blood flow measurements obtained by LDF and LSCI techniques cannot be compared directly even after "classical" normalization procedure. This technical problem is generated by the nonlinear relationship existing between LDF and LSCI flow data. The experiments have been performed on five healthy voluntary subjects (forearm) by using repeated ischemia/reperfusion cycles to induce the necessary skin blood flow changes. LDF and LSCI data were simultaneously acquired on the same region of interest. Considering the importance of this problem from the clinical point of view, it is concluded that the definition of new corrected algorithms for LSCI is probably a mandatory step that must be taken into account if LDF and LSCI blood flow have to be compared.

Skin perfusion evaluation between laser speckle contrast imaging and laser Doppler flowmetry

In the biomedical field, laser Doppler flowmetry (LDF) and laser speckle contrast imaging (LSCI) are two optical techniques aiming at monitoring – non-invasively – the microvascular blood perfusion. LDF has been used for nearly 40 years whereas LSCI is a recent technique that overcomes some drawbacks of LDF. Both LDF and LSCI give perfusion assessments in arbitrary units. However, the possible relationship existing between perfusions given by LDF and by LSCI over large blood flow values has not been completely studied yet. We therefore herein evaluate the relationship between the LDF and LSCI perfusion values across a broad range of skin blood flows. For this purpose, LDF and LSCI data were acquired simultaneously on the forearm of 12 healthy subjects, at rest, during different durations of vascular occlusion and during reactive hyperemia. For the range of skin blood flows studied, the power function fits the data better than the linear function: powers for individual subjects go from 1.2 to 1.7 and the power is close to 1.3 when all the subjects are studied together. We thus suggest distinguishing perfusion values given by the two optical systems.

Laser speckle contrast imaging: Multifractal analysis of data recorded in healthy subjects

The monitoring of microvascular blood flow can now be performed with laser speckle contrast imaging (LSCI), a new noninvasive laser-based technique. LSCI images have good spatial and temporal resolutions. Nevertheless, from now, few processing of these data have been performed to have a better knowledge on their properties. We herein propose a multifractal analysis of LSCI data recorded in the forearm of healthy subjects, based on the method from Halsey et al., one of the popular methods using the box-counting technique. In laser speckle contrast image time sequences, we studied time evolution of pixel values, as well as time evolution of pixel values averaged in regions of interest (ROI) of different sizes. The results are compared with the ones obtained with single-point laser Doppler flowmetry (LDF) signals recorded simultaneously to LSCI images. Our work shows that, for the range of scales studied and with the method from Halsey et al., time evolution of pixel values present narrow multifractal spectra, reminding the ones of monofractal data. However, we observe that when LSCI pixel values are averaged in ROI large enough and followed with time, the multifractal spectra become larger and closer to the ones of LDF signals. Single pixels from laser speckle contrast images may not possess the same multifractal properties as LDF signals. These findings could now be compared with the ones obtained with other ranges of scales and with data recorded from pathological subjects.

Multiscale Entropy Study of Medical Laser Speckle Contrast Images

Laser speckle contrast imaging (LSCI) is a noninvasive full-field optical imaging technique that gives a 2-D microcirculatory blood flow map of tissue. Due to novelty of commercial laser speckle contrast imagers, image processing of LSCI data is new. By opposition, the numerous signal processing works of laser Doppler flowmetry (LDF) data-that give a 1-D view of microvascular blood flow-have led to interesting physiological information. Recently, analysis of multiscale entropy (MSE) of LDF signals has been proposed. A nonmonotonic evolution of MSE with two distinctive scales-probably dominated by the cardiac activity-has been reported. We herein analyze MSE of LSCI data. We compare LSCI results with the ones of LDF signals obtained during the same experiment. We show that when time evolution of LSCI single pixels is studied, MSE presents a monotonic decreasing pattern, similar to the one of Gaussian white noises. By opposition, when the mean of LSCI pixel values is computed in a region of interest (ROI) and followed with time, MSE pattern becomes close to the one of LDF data, for ROI large enough. LSCI is gaining increased interest for blood flow monitoring. The physiological implications of our results require future study.