Active Versus Passive Infrared Thermography for Skin Cancer Detection: A Diagnostic Accuracy Study

Area of Science:

• Medical Imaging
• Dermatology
• Oncology

Background:

• Infrared thermography is a non-invasive method for detecting physiological changes in skin cancer.
• Its diagnostic accuracy for skin cancer requires further characterization.
• This study compares active and passive infrared thermography for distinguishing benign from malignant skin lesions.

Purpose of the Study:

• To compare the diagnostic performance of active (cooling-induced) and passive infrared thermography.
• To evaluate their effectiveness in differentiating benign from malignant skin lesions.
• To assess the utility of thermal contrast and temperature differentials for skin cancer diagnosis.

Main Methods:

• A clinical study involving 64 participants and 100 skin lesions (68 analyzed for accuracy).
• Acquisition of long-wave infrared images using passive and active (post-cooling) thermography.
• Histopathology served as the gold standard for diagnosis, with analysis of thermal contrast and temperature differentials (ΔT).

Main Results:

• Active thermography demonstrated superior diagnostic performance (91.1% sensitivity, 75.0% specificity) compared to passive thermography (17.9% sensitivity, 100% specificity).
• Malignant lesions exhibited significantly higher ΔT values, particularly during active thermal recovery.
• Receiver Operating Characteristic (ROC) analysis confirmed active thermography's superiority (AUC = 0.871) over passive imaging (AUC = 0.650).

Conclusions:

• Active infrared thermography enhances thermal contrast, significantly improving diagnostic sensitivity over passive imaging.
• This low-cost, non-invasive technique is a promising complementary tool for skin cancer triage.
• Active thermography is particularly valuable in resource-limited settings with restricted access to dermatological evaluation.