Exploring optical coherence tomography imaging depth to differentiate tissues at surgical margins

Area of Science:

• Veterinary Medicine
• Biomedical Imaging
• Surgical Oncology

Background:

• Optical coherence tomography (OCT) offers real-time tissue microstructure visualization.
• Accurate surgical margin assessment is crucial for effective treatment of canine soft tissue sarcoma (STS).

Purpose of the Study:

• To assess OCT image tissue depths (TD) and objective characteristics of different tissues at surgical margins in canine STS.
• To evaluate the utility of OCT for differentiating between sarcoma and adjacent healthy tissues.

Main Methods:

• A single observer analyzed 248 OCT images from 24 dogs with STS, evaluating four tissue types: sarcoma, skeletal muscle, adipose, and fascia.
• ImageJ software was used to measure tissue depths (TD) under normal, Threshold, and Binary conditions.
• Intra-observer variability was assessed by repeating measurements after one week.

Main Results:

• Light penetration (TD) decreased in the order: adipose > skeletal muscle > fascia > sarcoma across all image processing conditions.
• Neovascularization was present in 53.2% of sarcoma images.
• Distinct fascial lines surrounding muscle bundles were observed in 93.5% of skeletal muscle images.

Conclusions:

• Objective differences in OCT imaging characteristics exist between canine STS, skeletal muscle, adipose, and fascia.
• These OCT-based tissue distinctions can enhance observer interpretation and algorithm development for improved surgical margin assessment in canine STS.