Comparison of soft tissue handling protocols for identifying optical properties and morphology

Sample handling is an important consideration when aiming for replicating in vivo conditions ex vivo for the sake of validating imaging protocols and identifying biomarkers of disease. We tested five different handling methods: snap frozen in isopentane, directly frozen at -80°C, slowly frozen in a cryobox with and without cryopreservation media, and formalin fixed. The samples were imaged using optical coherence tomography (OCT) for qualitative and quantitative validation based on morphological features and optical properties. All handling methods were compared to fresh tissue samples using OCT-derived optical properties and morphological features. The results indicate a significant difference in the optical attenuation coefficient as well as morphological differences between the five different methods and support the hypothesis that proper sample handling is crucial for obtaining translatable results.