Thermography as a predictor of the more involved side in bilateral carotid disease: case history

Contact thermography using liquid crystals provides a simple, inexpensive method of evaluating carotid disease. It does not duplicate information provided by other noninvasive methods, because, whereas Dopplers give an indication of flow and degree of stenosis in the artery, thermography measures the actual hypoperfusion as demonstrated by diminished temperature in areas of the forehead supplied by branches of the ophthalmic artery. A 74-year-old man presented with bilateral carotid distribution TIAs. Carotid Dopplers and angiography revealed 99% occlusion of both internal carotid arteries. Contact thermography showed diminished temperature in the right supraorbital artery territory. The patient subsequently underwent carotid endarterectomy. Following induction of anesthesia but prior to carotid clamping, the patient became transiently hypotensive. Intraoperative EEG monitoring showed marked attenuation of the background rhythm on the right with preservation of background on the left. Normal rhythm was quickly restored with pharmacologic restoration of the blood pressure. This case illustrates the usefulness of thermography, which predicted the hemisphere in jeopardy when Dopplers and angiography showed equal bilateral disease.