Monitoring microvascular perfusion variations with laser speckle contrast imaging using a view-based temporal template method

PURPOSE

Laser speckle contrast imaging (LSCI) continues to gain an increased interest in clinical and research studies to monitor microvascular perfusion. Due to its high spatial and temporal resolutions, LSCI may lead to a large amount of data. The analysis of such data, as well as the determination of the regions where the perfusion varies, can become a lengthy and tedious task. We propose here to analyze if a view-based temporal template method, the motion history image (MHI) algorithm, may be of use in detecting the perfusion variations locations.

METHODS

LSCI data recorded during three different kinds of perfusion variations are considered: (i) cerebral blood flow during spreading depolarization (SD) in a mouse; (ii) cerebral blood flow during SD in a rat; (iii) cerebral blood flow during cardiac arrest in a rat. Each of these recordings was processed with MHI.

RESULTS

We show that, for the three pathophysiological situations, MHI identifies the area in which perfusion evolves with time. The results are more easily obtained compared with a visual inspection of all of the frames constituting the recordings. MHI also has the advantage of relying on a rather simple algorithm.

CONCLUSIONS

MHI can be tested in clinical and research studies to aid the user in perfusion analyses.

Online fast Biospeckle monitoring of drug action in Trypanosoma cruzi parasites by motion history image

This paper reports on the application of the motion history image (MHI) method on dynamic laser speckle processing as a result of a specific drug action on Trypanosoma cruzi parasites. The MHI procedure is based on human action recognition, and unlike other methods which use a sequence consisting of several frames for recognition, this method uses only an MHI per action sequence for recognition. MHI method avoids the complexity as well as the large computation in sequence matching-based methods and detects a change in the speckle pattern. Experimental results of MHI on real-time monitoring of activity (motility) under the influence of the drug demonstrate the effectiveness of the proposed method. The MHI showed an online result without loss of resolution and definition if we compare with routine LASCA method. The obtained results highlight the advantage of the MHI analysis over traditional qualitative image intensity-based methods and demonstrate the potential of measuring the activity of parasites via dynamic laser speckle analysis. The data was further numerically analyzed in the time domain, and the results presented the ability of the technique to monitor the action of the drug, particularly Epirubicin (100 μg/ml).

Real time and online dynamic speckle assessment of growing bacteria using the method of motion history image

This paper reports the application of the motion history image (MHI) method for biospeckle processing of a bacterial growth. The method avoids the complexity as well as the large computation in sequence-matching-based methods and detects whether the speckle structure has changed or not. Encouraging experimental results on the real-time evolution of the growing bacteria during 12 h demonstrate the effectiveness of the proposed method. The MHI presented an online result without loss of resolution and definition. In turn, the MHI also presented the ability to provide a close answer to the traditional offline method of generalized differences.