Oral squamous cell carcinoma diagnosis with time and frequency domain features from optical coherence tomography A-scan signals

Optical coherence tomography (OCT) is extremely useful in the screening and detection of oral cancers. But various challenges, such as its subjectivity, operator dependence in interpretation, and lack of quantitative outcomes, have been delaying its adoption in clinical decision-making. The objective of this research is to quantify various A-scan features embedded in the OCT signal through advanced signal processing techniques and machine learning algorithms. Ex vivo imaging of oral tissues (normal mucosa, carcinoma in situ, well-differentiated, and poorly differentiated oral squamous cell carcinoma) was conducted using a spectral domain optical coherence tomography system. Our A-scan dataset consisted of representative 1D signals obtained from different regions of the tissue bed. A set of 12 time- and 8 frequency-domain features were computed on each A-scan, and ten machine learning models were evaluated for binary and multi-label classification. LightGBM achieved the highest performance in both binary (accuracy: 0.8847, F1: 0.8878, AUC: 0.9539) and multi-label classification (accuracy: 0.8248, F1: 0.8201, AUC: 0.964). LightGBM was selected as the final model based on its superior and consistent performance across both classification paradigms. Our proof-of-concept feasibility study demonstrates good accuracy for differentiating oral mucosal tissues, highlighting the biomarker signature of A-scans.