[Digital dynamic telethermography: an aid in the study of vascular reactivity to cold]

Vascular reactivity to cold has been studied on 22 patients by means of digital dynamic thermography. Using an interface the thermographic images are digitized in real time and stocked in the computer. After the cooling (two minutes in water at 10 degrees C) the warming-up is followed by sequential thermographic images. Profiles of thermic evolution are represented for 12 regions of interest (at the level of each finger and two for the back of the hands). Four types of thermic profiles are observed: Type 0: all fingers and back of hands have the same basal temperature. After cooling the warming-up is immediate, synchronic for all fingers and goes on more or less rapidly. Type I: at the basal state all fingers have identical temperature. After cooling, the warming-up starts after a latency period of several minutes, which is identical for all fingers. After it the warming-up is fast and synchronic with a thermic "overshot" phenomenon at the end of the examination. Only the thumbs are warmed-up without a latency period. Type II: a latency period similar that of type I is observed but the following warming-up takes place with variable speeds for each considered finger. Type III: at the basal state the fingers are colder than the back of the hand. Spontaneously, some fingers are warmed only by the influence of the hand vertical position. After cooling, the warming-up takes place with variable speeds and after variable latency periods which are a characteristic of each finger.(ABSTRACT TRUNCATED AT 250 WORDS)