Medical thermal imaging procedure for HAVS assessment

Introduction: Hand Arm Vibration Syndrome (HAVS) is an occupational condition that affects subjects exposed to vibrating tools at the workplace and needs an accurate quantitative and objective diagnostic test to aid clinicians in the judgment of the degree of injury and adequate treatment. An objective assessing method is needed to provide a permanent evidence record of the degree of injury. In case of chronic or permanent injury an objective measure to specify an appropriate compensation is required. Methodology: Medical thermal imaging was used to monitor the hands exposed to an objective mechanical provocation test involving vertical vibration, for 2 minutes at 31.5Hz and 36 mm/s². This test was followed by a thermal provocation challenge (CST) of the hand for a period of 1 minute at 20°C. Images were taken during the whole procedure. In order to assess the peripheral temperature changes of the dorsal hand, a computational model was developed and the images were standardized and analyzed. Results: It was possible to discriminate between controls and patients (p<;0.05) and to identify through medical thermal imaging the affected fingers and their temperature changes, assessing objectively the stage of the injury. Conclusion: The proposed methodology is objective and repeatable, providing important physiological information of the evolutionary stage of HAVS. Medical thermal imaging is advised as a complementary diagnostic method, providing permanent evidence of the condition in support to medical history in medico-legal liabilities.