Optical coherence tomography and Raman spectroscopy for ex vivo characterization of canine skin and subcutaneous tumors: preliminary results

Abstract

Cancer is one of the leading causes of companion animal mortality. Up to 30% of all canine and feline tumors appear on or directly under the skin. To date, only a limited number of studies applied biophotonics techniques for optical characterization and detection of tumors in pets. In this work, we acquired ex vivo optical coherence tomography (OCT) images and Raman spectra of native skin and the most common canine and feline skin and subcutaneous tumors; lipomas, mast cell tumors, and soft tissues sarcomas. Lipomas exhibited the most distinctive tissue morphology (i.e., honeycomb structure) and biochemistry (lipid-related Raman peaks of 1063, 1301, and 1652 cm-1). Moreover, lipomas had significantly higher values of coefficient of variation (CV) retrieved from OCT images. On the other hand, all other tissues exhibited signal-dense and highly scattering OCT images. Despite the similar Raman spectra, we detected the malignant tumors with the sensitivity and specificity of 100% and 88.2%, respectively. Additionally, malignant tumor types were distinguished with an accuracy of 78.6%. Our results showed the potential of OCT and Raman techniques for ex vivo optical characterization of common canine and feline tumors and native skin.