OPTICAL CLEARING OF HUMAN SKIN FOR THE ENHANCEMENT OF OPTICAL IMAGING OF PROXIMAL INTERPHALANGEAL JOINTS

Ekaterina A. Kolesnikova1, Aleksandr S.Kolesnikov1, Urszula Zabarylo2,

Olaf Minet2, Elina A. Genina1, Alexey N. Bashkatov1,

Valery V. Tuchin1,3,4

1Saratov State University, 2Medizinische Physik und Optische Diagnostik,

Charité – Universitätsmedizin Berlin, 3Institute of Precision Mechanics and

Control RAS, 4Optoelectronics and Measurement Techniques Laboratory

e-mail: ekaterina.a.kolesnikova@mail.ru

Saratov State UniversityDepartment of Optics

and Biophotonics

Saratov Fall Meeting 2013

Motivation

The transillumination optical imaging is a prospective technique for the diagnosis of rheumatoid arthritis in humans.

But the relatively low contrast and poor spatial resolution of the result images limits the usage of the technique for the finding of differences between healthy and pathology joints.

Goal of the study is to enhance the technique by reduction of skin light scattering at using of optical clearing method

Saratov State UniversityDepartment of Optics

and Biophotonics

Saratov Fall Meeting 2013

Materials and methods

Experimental setup

Fig. 1. The exterior of the experiment (left image) and the transillumination system with 3 laser diodes (right image).

Saratov State UniversityDepartment of Optics

and Biophotonics

Saratov Fall Meeting 2013

illuminating LEDs(670, 820, and 904 nm)

monochromatic digital CCD camera of an 8 bit dynamic range and variable exposure time

finger

The beam of the laser diodes was focused upon a spot diameter of ≤1 mm on the finger surface

Using laser diodes of a fixed power, the exposure time depends on the diameter of the finger and the manifestation of rheumatoid arthritis

Materials and methodsTested specimens

The experiments were carried out in vivo with human skin. Female (25 years) participated in the experiments. Proximal interphalangeal (PIP) joints of index finger (1.6 cm) and middle finger (1.8 cm) were investigated The scattered light images obtained by transillumination were taken from the PIP joints of index finger and middle finger to study the possibility of optical clearing application in optical diagnosis of rheumatoid arthritis

Optical clearing agents

Dehydrated glycerol and hand cream with urea (5%) were used as OCAs.

Refractive indices of glycerol are: 1.469 at 670 nm 1.466 at 820 nm 1.465 at 904 nm

Saratov State UniversityDepartment of Optics

and Biophotonics

Saratov Fall Meeting 2013

Materials and methodsContrast calculationContrast was calculated in region of interest (ROI) near the middle of the finger joint (fig.2) with special software designed in LabView programming environment

Fig. 2. An image of ROI for the contrast calculation (blue rectangle)

Saratov State UniversityDepartment of Optics

and Biophotonics

Saratov Fall Meeting 2013

ResultsSaratov State University

Department of Optics and Biophotonics

Saratov Fall Meeting 2013

Fig. 3. An image of finger joint under the action of glycerol in a transmission mode: left image – before agent application, right image – 60 min after agent application.

Wavelength is 670 nm.

ResultsSaratov State University

Department of Optics and Biophotonics

Saratov Fall Meeting 2013

Fig. 4. An image of finger joint under the action of glycerol in a transmission mode: left image – before agent application, right image – 60 min after agent application.

Wavelength is 820 nm.

ResultsSaratov State University

Department of Optics and Biophotonics

Saratov Fall Meeting 2013

Fig. 5. An image of finger joint under the action of glycerol in a transmission mode: left image – before agent application, right image – 60 min after agent application.

Wavelength is 904 nm.

ResultsSaratov State University

Department of Optics and Biophotonics

Saratov Fall Meeting 2013

Fig. 6. An image of finger joint under the action of hand cream in a transmission mode: left image – before agent application, right image – 60 min after agent application.

Wavelength is 670 nm.

ResultsSaratov State University

Department of Optics and Biophotonics

Saratov Fall Meeting 2013

Fig. 7. An image of finger joint under the action of hand cream in a transmission mode: left image – before agent application, right image – 60 min after agent application.

Wavelength is 820 nm.

ResultsSaratov State University

Department of Optics and Biophotonics

Saratov Fall Meeting 2013

Fig. 8. An image of finger joint under the action of hand cream in a transmission mode: left image – before agent application, right image – 60 min after agent application.

Wavelength is 904 nm.

ResultsSaratov State University

Department of Optics and Biophotonics

Saratov Fall Meeting 2013

Table 1. Contrast in a ROI near the middle of the joint for the case of glycerol topical application

Time, min 670 nm 820 nm 904 nm

0 0.348 0.397 0.409

5 0.324 0.449 0.495

15 0.304 0.446 0.426

30 0.389 0.528 0.544

60 0.367 0.442 0.535

ResultsSaratov State University

Department of Optics and Biophotonics

Saratov Fall Meeting 2013

Table 2. Contrast in a ROI near the middle of the joint for the case of hand cream with 5% urea application

Time, min 670 nm 820 nm 904 nm

0 0.505 0.465 0.530

5 0.518 0.503 0.542

15 0.505 0.525 0.596

30 0.412 0.439 0.490

60 0.471 0.414 0.458

SummarySaratov State University

Department of Optics and Biophotonics

Saratov Fall Meeting 2013

Thus, our results shows that glycerol and hand cream with

5% urea allow obtaining of more distinct image of finger

joint.

In that way we may conclude that investigated OCAs at

topical applications to skin can be effectively used as

enhancer for the technique for the finding of differences

between healthy and pathology joints in transillumination

mode.

AcknowledgementsSaratov State University

Department of Optics and Biophotonics

Saratov Fall Meeting 2013

This research was supported by:

Grant of President of RF NSH-1177.2012.2

FiDiPro, TEKES Program (40111/11), Finland

RF State contracts № 14.512.11.0022 and 14.B37.21.0728

Thanks for your attention!