Thermal Imaging of the Tongue Surface as a Predictive Method in the Diagnosis of Type 2 Diabetes Mellitus

Abstract

Over the past 20 years, the high prevalence of diabetes has become a global public health problem.

Background: The objective of this study was to develop a non-invasive screening method for diabetes which will enable the detection of the disease at an early stage.

Methods: This study included 63 adult patients of both sexes: 30 patients with type 2 diabetes (t2DM) and 33 healthy volunteers. The temperature distribution on the tongue's dorsum and apex surface was studied in patients after a mouth-cooling procedure had been introduced. The study used an FLIR T540 thermal imaging camera. An analysis of the correlation between the ∆T values of the tongue dorsum and apex and the glycated hemoglobin (HbA1c) level was performed.

Results: The median of the average dorsum temperature measured 10 min after mouth rinsing was almost 0.8 [°C] lower than for healthy individuals. Also, studies showed a positive average correlation with a Pearson coefficient of r = 0.46 between the HbA1c level and the ∆T of the tongue dorsum.

Conclusions: Tongue temperature measured using the IRT showed a correlation with standard biochemical parameters; it may also differentiate patients and constitute a specific screening method for patients with t2DM.

Keywords: dynamic infrared thermal image; glycated hemoglobin level; imaging method; tongue; tongue temperature; type 2 diabetes mellitus.

Figure 1

Thermal images of a representative patient (from the diabetes group) obtained 2 and 10 min after mouth rinsing.

Figure 2

Thermal images of a representative healthy volunteer (from the control group) obtained 2 and 10 min after mouth rinsing.

Figure 3

Mean temperature difference in tongue dorsum between control (C) and study groups (D—diabetes), obtained 10 min after rinsing the mouth with water.

Figure 4

Temperature difference of tongue dorsum for control (C) and study groups (D—diabetes) obtained between 2 and 10 min after rinsing the mouth with water.

Figure 5

Correlations (r = 0.46) between the glycated hemoglobin (HbA1c) concentration and the difference in the tongue dorsum temperature between 2 and 10 min after rinsing the mouth.

Figure 6

Correlations between the glycated hemoglobin (HbA1c) concentration and the difference in tongue apex temperature between 2 and 10 min after rinsing the mouth.

Figure 7

Temperature difference of tongue dorsum for patient group, characterized and divided according to HbA1c level, assuming L < 7% and H ≥ 7%, obtained between 2 and 10 min after rinsing mouth with water.

Figure 8

Temperature difference of tongue apex for patient group, characterized and divided according to HbA1c level, assuming L < 7% and H ≥ 7%, obtained between 2 and 10 min after rinsing mouth with water.