Thermography screening of thyroid gland: how to distinguish health from pathology
This research is organized to investigate if the thermal gradient (Tgrad) (difference between temperature maximum and minimum in the region of interest over thyroid gland on neck thermogramm) could be a marker of normal/ abnormal thyroid function and, if so, find out the cut-off value and check it screening validity. Materials and methods. Thermography examination was performed using a TVS-300 med (S-Petersburg, Russia) thermal imaging camera with a resolution of384 * 288 pixels and sensitivity was grad calculated. Totally 1025 pts with different tthyroid pathology (group 1: female 944, age 15-90 (55,4±15,8), male 81, age 14-86 (53,6±18,8)), and 395 healthy persons (group 2: male 324 age 17-26 (21,8±4,4), female 71 age 16-70т (34,6±12,7)) were investigated. To check the quality of the model another 314 persons (18 male and 296 female) were studied in screening mode. Results. Calculated Tgrad value was 1,65±0,53оС, Ме 1,53(1,24; 1,90) and 0,98±0,23°С, Me 1,01(0,82; 1,15) for group 1 and 2 accordingly. By mean of binary logistic regression analysis we found good correlation between T grad value and presence/absence of thyroid pathology: significance level р2 =838,84, df=1, β0 = 9,984, β = -9,033. Area under curve in ROC analysis was 0,922 (95 % CI 0,908; 0,935), рgrad was 1,21оС for maximal sensitivity (79,8 %) and specificity (83,3 %). In screening evaluation, according to optimal cut-off value 1,2 °C for Tgrad, 82,2 % of cases were classified correctly: true-positive and true-negative results were achieved in 258 from 314 pts. Conclusion. Thermography test, based on Tgrad value calculation, could help to distinguish persons with normal and abnormal function of thyroid gland..