The use of optical coherence tomography to enhance surgical margin assessment for canine mast cell tumors

Experiment 1: Objective: To document the appearance of artifacts created by commonly encountered surgical conditions and instrumentation on optical coherence tomography (OCT) and compare these findings with histopathology. Study design: Ex vivo study Animals: 5 canine cadavers Methods: Skin, subcutaneous fat, skeletal muscle, and fascia samples were obtained from fresh canine cadavers. Blood pooling, hemostatic crushing, scalpel blade cut, monopolar electrosurgery, bipolar vessel sealing device and ultrasonic energy surgical artifacts were induced on each tissue type. Each specimen was interrogated with OCT and subsequently histologically processed. Results: The majority of surgical instrumentation used for tumor excision created a high-scattering region with local architectural disruption. Blood pooling was visible as a high- scattering layer overlying tissue with normal architecture. Only the scalpel blade created a focal, low-scattering area representing a sharply demarcated cut within the tissue distinct from the appearance of other instrumentation. Conclusion: Common surgical instruments and conditions encountered during tumor excision produced high-scattering OCT artifacts in tissues commonly seen at surgical margins (SM). Clinical Significance: The clinical value of OCT hinges upon the ability of personnel to interpret this novel imaging and recognize artifacts. Defining and describing the appearance of common surgical artifacts provides a foundation to create image libraries with known histological and OCT interpretation, ultimately improving the diagnostic accuracy of OCT for assessment of SMs. Experiment 2: Objectives: To develop a training set in which normal and abnormal histological features are compared with optical coherency tomography (OCT) images from the surgical margins (SM) of excised mast cell tumors (MCTs). Secondly, to determine the feasibility and utility of OCT imaging to direct pathological sectioning of resected MCTs. Study design: Prospective, ex vivo study Animals: 15 dogs with 22 MCTs Methods: MCTs were excised, and a specific trimming/sectioning plan determined for each specimen. For the first objective, regions of interest (ROI) were imaged with OCT and compared to standard histopathology to define the normal and neoplastic features of tissues comprising the excised SM. For the second, regions suspicious for neoplastic disease were inked, imaged with OCT, and compared with standard and tangential trimming histopathologic diagnoses. Completeness of resection and agreement between OCT and histopathologic evaluation of MCT SM was determined. Results: Skeletal muscle appeared dense and high-scattering with a striated appearance. Adipose tissue was low-scattering with a honeycombed appearance. Fascia created a linear and discrete high-scattering band. MCT was characterized by a dense, disorganized, and high scattering appearance with a lack of microstructural architecture. Forty-six percent of MCTs were completely excised and 54% removed with incomplete SM. OCT agreed with standard histopathology in 69% cases and displayed disagreement in the remaining 31%. Of the cases that disagreed, 75% showed OCT incomplete and histologically complete SM. Conclusion: OCT can be used to characterize different tissue types comprising the SM of resected MCTs. This information can then be used to identify areas of incomplete tumor resection and help guide subsequent pathologic evaluation. Clinical Significance: Standard histopathological processing can be complimented by OCT to screen fresh tissue specimens and guide targeted sections for SM assessment of MCT. Future studies are warranted to determine the diagnostic accuracy of OCT guided histopathologic sectioning and its utility as a preliminary screening tool.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

VMS-Veterinary Clinical Medcne

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2020

Author dc:creator

• Cocca, Christina Julia

Contributors dc:contributor

• Fan, Timothy
• Selmic, Laura
• Selting, Kimberly
• Vieson, Miranda

• Canine
• mast cell tumor
• optical coherence tomography
• surgical margin
• tissue trimming
• surgical artifact
• histopathologic sectioning

Statement dc:rights

• Copyright 2019 Christina Cocca

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/106333

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/106333