Infrared thermography in the diagnosis of Raynaud's phenomenon in vibration-induced white finger.

BACKGROUND

Frequent use of vibrating tools over several years may lead to a neurovascular disturbance of finger circulation with the development of typical Raynaud's phenomenon, attacks being triggered by vibration and/or cold exposure. The condition is recognized as an occupational disease and known as vibration-induced white finger (VWF). Aim of the present study was to evaluate the usefulness of infrared thermography (IRT) with a cold provocation test in the diagnosis of Raynaud's phenomenon in VWF.

PATIENTS AND METHODS

24 patients with the diagnosis of VWF, previously established by other methods, were compared with 12 matched control subjects. We carried out IRT-measurements simultaneously on both hands before, directly after and 5, 10, 15, 20, and 30 mins following a 3 min exposure of both hands to a waterbath of 12 degrees C. The results of temperature measurements of all fingers were analyzed and the time to complete rewarming of all fingers was recorded.

RESULTS

The basal thermograms did not differ between both groups, whereas the mean finger temperatures after cold exposure were significantly lower in VWF-patients compared to controls, with a considerable individual overlap between both groups. Therefore, determination of absolute finger temperature reveals not to be a useful diagnostic tool in individual cases, but might be helpful for pharmacological studies (group-analysis). In contrast to absolute finger temperatures, the parameter of rewarming time after cold exposure revealed to be diagnostic on an individual basis: a complete rewarming after 15 min indicates a normal vascular reactivity and an incomplete rewarming 30 min following the cold provocation points to an impaired vascular reactivity due to VWF.

CONCLUSIONS

IRT revealed to be a useful tool in the diagnosis of Raynaud's phenomenon in VWF, and provides a sufficient documentation suitable for further follow-up examination.