Abstract 1132P
Background
Conventional histology, being the gold standard in assessment of biological tissues, is known to be invasive, laborious and time-consuming. New methods, which could at least partially eliminate/automate some steps of histological examination, are highly demanded. In this context, we proposed a technique based on optical coherence elastography (OCE) enabling in vivo real-time assessment of tissue structure similar to histological segmentation.
Methods
The study used a home-made multimodal OCT setup to perform quantitative mapping of tissue elasticity by compression elastography principle. The tumor was slightly compressed by the OCT-probe through translucent silicone layer with pre-calibrated stiffness. The produced strains were found by analyzing interframe phase variations. Comparing strains in silicone and tumor, its Young’s modulus was mapped with resolution ∼40-50 μm. Specific modulus ranges for main morphological components of tumor were found by comparing histological and OCE images. 72 Balb/c mice bearing breast cancer 4T1 were divided in 3 equal groups treated by: PBS (control), Bevacizumab (15 mg/kg) and Cisplatin (6 mg/kg). Drugs induce antiangiogenic and cytotoxic actions respectively and different changes in tumor morphology are suggested. At days 5, 7 and 9 post therapy, OCE and histological images (H&E) were obtained. OCE maps were segmented based on specific stiffness ranges and accurately compared with histological segmentation.
Results
OCE revealed post therapeutic morphological components by specific stiffness ranges: viable tumor cells (> 621 kPa); dystrophic tumor cells (411-620 kPa); edema (231-410 kPa) and necrosis (< 230 kPa). OCE-segmented boundaries and areas of morphological components showed high correlation with histology (r ∼ 0.96, p < 0.001). At day 9 (for maximal therapy effect), we found: Bevacizumab-induced edema – 58±11 % (OCE) / 63±3 % (H&E); Cisplatin-induced necrosis – 72±3 % / 71±15 %. In PBS group viable tumor cells prevailed – 78±2 % / 76±9 %.
Conclusions
OCE has proven to be a non-invasive (albeit contact) method enabling in vivo segmentation of morphological tissue components with an accuracy similar to that of conventional histological segmentation. Numerous other experimental / clinical applications can be foreseen.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Russian Science Foundation, grant 18-75-10068.
Disclosure
All authors have declared no conflicts of interest.