Laser transillumination for diagnosis of rheumatoid arthritis

In this work, the special portable apparatus was constructed for performing the transillumination examination on interphalangeal joints of patients suffering from rheumatoid arthritis. It consisted of He-Ne laser with optics for collimated illumination, special holder for placing the finger (perpendicular to optical axis, dorsal site towards camera), and CCD camera with memory stick. The captured images in JPEG format with 1152x864 resolution were converted into the gray level pictures and analyzed by means of image processing program from OPTIMAS. 35 ill patients and 11 healthy volunteers were examined. The histograms and 35 luminances were calculated. The average function was applied in order to calculate the mean gray level values in images of corresponding fingers of healthy subjects. These values were compared with values calculated for ill persons. We proved that that transillumination images may have a diagnostic value. For RA suffering patients the corresponding transillumination images represented the lower gray level values than the average value of finger of health volunteers. For II finger of left hand 96% images of ill persons have lower gray level and in case of right hand it was 93%. This proves that basing in transillumination one can diagnose with high probability the patient with rheumatoid arthritis.