Structured Illumination Microscopy and a Quantitative Image Analysis for the Detection of Positive Margins in a Pre-Clinical Genetically Engineered Mouse Model of Sarcoma.
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Intraoperative assessment of surgical margins is critical to ensuring residual tumor does not remain in a patient. Previously, we developed a fluorescence structured illumination microscope (SIM) system with a single-shot field of view (FOV) of 2.1 × 1.6 mm (3.4 mm2) and sub-cellular resolution (4.4 μm). The goal of this study was to test the utility of this technology for the detection of residual disease in a genetically engineered mouse model of sarcoma. Primary soft tissue sarcomas were generated in the hindlimb and after the tumor was surgically removed, the relevant margin was stained with acridine orange (AO), a vital stain that brightly stains cell nuclei and fibrous tissues. The tissues were imaged with the SIM system with the primary goal of visualizing fluorescent features from tumor nuclei. Given the heterogeneity of the background tissue (presence of adipose tissue and muscle), an algorithm known as maximally stable extremal regions (MSER) was optimized and applied to the images to specifically segment nuclear features. A logistic regression model was used to classify a tissue site as positive or negative by calculating area fraction and shape of the segmented features that were present and the resulting receiver operator curve (ROC) was generated by varying the probability threshold. Based on the ROC curves, the model was able to classify tumor and normal tissue with 77% sensitivity and 81% specificity (Youden's index). For an unbiased measure of the model performance, it was applied to a separate validation dataset that resulted in 73% sensitivity and 80% specificity. When this approach was applied to representative whole margins, for a tumor probability threshold of 50%, only 1.2% of all regions from the negative margin exceeded this threshold, while over 14.8% of all regions from the positive margin exceeded this threshold.
Published Version (Please cite this version)10.1371/journal.pone.0147006
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Associate Professor of Pathology
I am active in translational research involving gastrointestinal/hepatobiliary pathology [specifically transplant related pathology (GVHD and rejection) and carcinogenesis of the pancreas] and bone and soft tissue malignancies [imaging techniques for intraoperative margin assessment].
Barbara Levine University Professor
My clinical interests are the multi-modality care of patients with bone and soft tissue sarcomas and developing new sarcoma therapies. My laboratory interests include utilizing mouse models of cancer to study cancer and radiation biology in order to develop new cancer therapies in the pre-clinical setting.
Robert W. Carr, Jr., Professor of Biomedical Engineering
Dr. Ramanujam is the Robert W. Carr Professor of Biomedical Engineering, and also a faculty member in the Global Health Institute and Dept. Pharmacology and Cell Biology at Duke University. She is an innovator, educator and entrepreneur and her mission is to develop and leverage technology to have the most wide reaching impact in women’s health. She directs the center for Global Women’s Health Technologies (GWHT), a partnership between the Pratt School of Engineering and the Duke
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