[Diagnostic test for detection of cervical lymph node metastasis from oral squamous cell carcinoma via infrared thermal imaging].

objectiveTo evaluate the diagnostic performance of a non-invasive, non-radiating, economical and convenient infrared thermal imaging in the detection of oral squamous cell carcinoma (OSCC) cervical lymph node metastasis, and evaluate its applicability via parallel test and series test.

methodsThis study was a prospective clinical study which passed the ethical review by the Biomedical Ethics Committee, Hospital of Stomatology, Peking University, and had been submitted for clinical trial registration. Totally 74 OSCC patients who were to undergo a neck dissection were included in this study. The inclusion criteria were patients who: (1) were pathologically diagnosed as malignant tumors and planned to undergo surgical treatment including neck dissection; (2) agreed to participate in this study. The exclusion criteria were those who: (1) had undergone surgeries at head and neck previously; (2) with a history of systemic tumor adjuvant therapies such as radiotherapy or chemotherapy etc; (3) were unwilling or unable to cooperate. Basal information as well as clinical examination results were collected, such as physical examination and contradictive enhanced CT. Besides, infrared thermal imaging was done ahead of surgery. Analysis of the diagnostic power of infrared thermal imaging followed the principles of diagnostic test. The positive signs of infrared thermal imaging were: (1) asymmetric thermographic pattern including vascular pattern in ROI; (2) thickening image of unilateral facial artery/vein, submental artery/vein or external carotid artery; (3) surface temperature of ROI raised over 1 °C compared with the opposite side; (4) changes of neck profile with abnormal temperature pattern. The gold standard of this diagnostic test was pathology diagnosis of cervical lymph nodes.

resultsThe sensitivity of infrared thermal imaging was 75.0%, while the specificity was 69.0%, accuracy was 71.6%, positive predictive value was 64.9% and negative predictive value was 78.4%. The sensitivity of parallel test which stood for the combination of infrared thermal imaging and conventional clinical examinations was 87.9% while the specificity of series test was 97.6%.

conclusionInfrared thermal imaging is a promising non-invasive, non-radiating and economical tool in the detection of cervical lymph node metastasis from OSCC when combined with conventional pre-operative examination.