1. Diagnostics of vascular reactions triggered by weak allergens using the laser speckle imaging with the long exposure time
Vyacheslav Kalchenko MD, PhD
In Vivo Optical Imaging Unit,
Department of Veterinary Resources
Weizmann Institute of Science, Rehovot, Israel

2. Motivation
An allergy is a hypersensitivity disorder of the immune system.
A variety of tests exist to diagnose allergic conditions.

3. Motivation
Challenge Tests: A very small amount of an allergen is inhaled or taken by mouth.
IgE Skin Tests: A very small amount of certain allergens is put into skin.
Blood Tests: This test involves drawing blood, so results are not available as rapidly as with skin tests.

4. Skin Testing for Allergies
Scratch test
Intradermal test
Patch testing

5. Allergy testing 21th Century
Clinical studies
wikipedia.org
Patch test

6. Patch test Allergy testing 21th Century Clinical studies
Patch test

7. Allergy testing 21th Century
Preclinical studies
Mouse Ear Swelling Test (MEST)

8. Goal
To develop an imaging system for assessment of vascular changes induced by immune reaction (allergens) as well as contact irritants
Preclinical studies

9. Hypothesis - Itching - Redness - Burning - Swelling Histamine
SENSITISATION
Acute INFLAMATION
Contact irritant
Allergen
Trigger
Methyl salicylate h

10. In Vivo Imaging Center
Multiple modalities

11. Hypothesis Acute inflammation (two components):
Alterations in vascular caliber that lead to an increase in blood flow
Structural changes in the microvasculature that permit plasma proteins
and leukocytes to leave the circulation
I. Laser Speckle Imaging (LS) might be used
to asses blood flow alterations
II. Fluorescence Imaging (FI) might be used
to asses plasma proteins extravasation
(VERIFICATION, ONLY FOR PRECLINICAL USE)
Mouse ear model

12. Laser Speckle Imaging LSI
Motion Contrast t
frame
Laser light source
CCD camera
Blood vessel
Kalchenko et al., Laser Physics Letters. V7., Issue

13. Calculation of Laser Speckle (motion) Contrast
frame
EXPOSURE TIME: 50 ms
Where σ is a standard deviation of the CCD intensity counts at pixel (x,y) during n frames. n is the number of frames acquired and <x,y> is the mean value of CCD intensity counts at pixel (x,y) over the n frames
Kalchenko et al., Laser Physics Letters. V7., Issue

14. Setup of LSFI Methyl salicylate PC Workstation CCD camera Fluorescent
microscope
Methyl salicylate
Area of a weak contact irritant application
Laser module
Mouse external ear
Lab mouse

15. Long Exposure Speckle Imaging
Lymphatic vessels
(650 ms)
Blood vessels
(50 ms)
Kalchenko et al., JBO. V17., Issue

16. Extended exposure time
frame
EXPOSURE TIME: 350 ms
Where σ is a standard deviation of the CCD intensity counts at pixel (x,y) during n frames. n is the number of frames acquired and <x,y> is the mean value of CCD intensity counts at pixel (x,y) over the n frames
Kalchenko et al., Laser Physics Letters. V7., Issue

17. Results Long Exposure LS imaging (350 ms) Methyl salicylate (MS)
Before
30 min after MS aplication

18. Results Color coded (PCA) FI imaging of FITC extravasation Principle
Component
Analysis
FITC (Fluorescein isothiocyanate–dextran) was
administrated 30 min after Methyl salicylate application

19. Conclusions
We have developed an imaging approach for assessment of vascular changes induced by contact irritants based on laser speckle imaging with multi-exposure time
Further development is required to test sensitivity of the system to different weak contact allergens

20. Coauthors and collaborators
Dr. Yuri Kuznetsov
Department of Veterinary Resources
Weizmann Institute of Science, Rehovot, Israel
Prof. Alon Harmelin
Department of Veterinary Resources
Weizmann Institute of Science, Rehovot, Israel
Prof. Igor Meglinski
Department of Physics,
University of Otago, Dunedin, New Zealand