Maxim Vilensky, Saratov State University, Russia Oxana V. Semyachkina-Glushkovskaya, Saratov State University, Russia

Denis A. Alexandrov, Saratov State Medical University, Russia

Valery V. Tuchin, Saratov State University, Russia; Institute of Precision Mechanics and Control, Russian Academy of Sciences,

RAS, Russia; University of Oulu, Finland

Polina A. Timoshina, Saratov State University, Russia Viktor A. Kuleshov, Saratov State Medical University, Russia

Igor A. Semyachkin-Glushkovsky, Saratov State University, Russia

MONITORING OF MICROCIRCULATION BY FULL FIELD SPECKLE-CORRELATION TECHNIQUE IN ANIMAL STUDY

2

Outlines The results of experimental study of full field laser

speckle imaging in application to cortex and pancreas microcirculation monitoring of laboratory rats at stress-induced stroke, modeled hemorrhagic pancreatitis and impact of exogenous agents are presented

The results of phantom study and nail fold capillary blood flow monitoring are also presented

Analysis and computing of speckle images

M

m

N

nkk nmIMNI

1 1

,1

M

m

N

nkkkI InmIMN

1 1

2,1

cg exp2

vKс

kkIk IV The contrast of speckle-modulated images

The intensity of the speckle field

Correlation function of strength fluctuation of scattering light

Correlation time of strength fluctuation

Standard deviation of intensity

(1)

(2)

(3)

(4)

(5)

Investigated objects

2 – Capillary bundle with scatters flow

1 - Rats microcirculation

monitoring 3 – human nail bed microcirculation

Cortex microcirculation monitoringCortex microcirculation monitoring

Experimental setup

Schematic diagram of experimental setup:1. He–Ne laser GN 5P with the wavelength 633 nm; 2. Optical fiber; 3. Detector (CMOS camera Basler A602f) (in the speckle imaging regime); 4.

Lens tube of the microscope with microscopic objective (LOMO, 10x) and 8 element LED-illuminator (central wavelength ~530 nm); 5. Object of study (in the microscopy regime)

Speckles contrast data fluctuation via blood flow changes

1. Mean contrast values for rats one day after the stress exposure;

2. Mean contrast values for rats immediately after action;

3. Mean contrast values for healthy animals.

Pancreas microcirculation monitoring

The pancreas capillary blood flow studied at different states of the experimental animal

Contrast variations of time-averaged speckles caused by pancreas blood flow velocity reperfusion changes

The pancreas capillary blood flow studied by digital image microscopy at different states of the experimental animal

The pancreas capillary blood flow studied by digital image microscopy at different states of the experimental animal at

reperfusion

Phantom particles flow visualisation

Speed-contrast relation ship

Speed-contrast relationship for scatters flow;Tube diameter 3 mm (left curves) & 50 mm (right curve)

0 100 200 300 400 5000,0

0,1

0,2

0,3

0,4

<V>

v, m/sec

Nail fold speckle images

Speckle contrast variations due to vessels overcomression

Contrast

Time, sec

Summary

Contrast of time-averaged speckles, used as a diagnostic parameter, characterized by a rather high sensitivity to changes in blood microcirculation in superficial layers of the internals caused by pathological changes or external factors

The experimental study of the blood flow velocity dynamics under conditions of stroke in laboratory rats demonstrates high efficiency of the developed instrument and algorithm for data acquisition and processing, implementing the method of full ｭ field speckle ｭ imaging, in monitoring of the blood microcirculation state in the brain cortex, affected by pathological changes or action of agents

Monitoring of blood flow during the pancreatitis showed a good correlation between data obtained from speckle-correlometry monitoring and dynamic microscopic imaging studies. No significant changes in blood flow existing after prolonged ischemia (10, 15 min), probably indicate the appearance of the irreversible disorders of pancreas blood flow regulatory mechanism. In contrast, after 5 min of ischemia, there are significant changes of blood flow velocity.

Acknowledgments

The research has been made possible by program: FiDiPro TEKES (40111/11) and grants: RFBR #11-02-00560-а, #224014; PHOTONICS4LIFE of FP7-ICT-2007-2; Projects: #1.4.09, #2.1.1/4989 and #2.2.1.1/2950 of RF Ministry of Education and Science; RF Governmental contracts: 02.740.11.0879, 14.B37.21.0563, 11.519.11.2035