Critical evaluation of the use of thermography in the investigation of scintigraphically cold thyroid nodules.

One hundred and fifty-five cases of scintigraphically "cold" thyroid nodules were examined telethermographically to determine their thermal gradient. All nodules hyperthermic greater than or equal to 1.5 degrees C were successively removed, as were those (regardless of the thermal gradient) present in men, those in women younger than 21 years and older than 45 years of age, and those clinically suspect, the latter regardless of age or sex of the patient. Of 95 operated cases, 79 proved to be benign or nontumoral nodules, and 16 were carcinomas at histology. Hyperthermia greater than or equal to 1.5 degrees C had been present in 43% of the benign cases and in only 25% of the carcinomas. Out of ten cases were hyperthermia greater than or equal to 2 degrees C, none was a carcinoma. A malignancy was found in 26% of 23 normothermic cases, 17.6% of 34 slightly hyperthermic cases, and only 10.5% of 38 markedly hyperthermic (greater than or equal to 1.5 degrees C) cases. There was no evident correlation between the thermal gradient and the clinical diameter of the thyroid nodule. Our study affirms that thermography is not reliable when used to select cold thyroid nodules for surgical removal.