AUTHOR=Ram Ann S. , Matuszewska Kathy , McKenna Charly , Petrik Jim , Oblak Michelle L. 

TITLE=Validation of a semi-quantitative scoring system and workflow for analysis of fluorescence quantification in companion animals

JOURNAL=Frontiers in Veterinary Science

VOLUME=11

YEAR=2024

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2024.1392504

DOI=10.3389/fvets.2024.1392504

ISSN=2297-1769

ABSTRACT=<sec id="sec1"><title>Significance</title><p>Many commercially available near-infrared (NIR) fluorescence imaging systems lack algorithms for real-time quantifiable fluorescence data. Creation of a workflow for clinical assessment and <italic>post hoc</italic> analysis may provide clinical researchers with a method for intraoperative fluorescence quantification to improve objective outcome measures.</p></sec><sec id="sec2"><title>Aim</title><p>Scoring systems and verified image analysis are employed to determine the amount and intensity of fluorescence within surgical specimens both intra and postoperatively.</p></sec><sec id="sec3"><title>Approach</title><p>Lymph nodes from canine cancer patients were obtained during lymph node extirpation following peritumoral injection of indocyanine green (ICG). First, a semi-quantitative assessment of surface fluorescence was evaluated. Images obtained with a NIR exoscope were analysed to determine fluorescence thresholds and measure fluorescence amount and intensity.</p></sec><sec id="sec4"><title>Results</title><p><italic>Post hoc</italic> fluorescence quantification (threshold of Hue = 165–180, Intensity = 30–255) displayed strong agreement with semi-quantitative scoring (<italic>k</italic> = 0.9734, <italic>p</italic> &lt; 0.0001). Fluorescence intensity with either threshold of 35–255 or 45–255 were significant predictors of fluorescence and had high sensitivity and specificity (<italic>p</italic> &lt; 0.05). Fluorescence intensity and quantification had a strong association (<italic>p</italic> &lt; 0.001).</p></sec><sec id="sec5"><title>Conclusion</title><p>The validation of the semi-quantitative scoring system by image analysis provides a method for objective <italic>in situ</italic> observation of tissue fluorescence. The utilization of thresholding for ICG fluorescence intensity allows <italic>post hoc</italic> quantification of fluorescence when not built into the imaging system.</p></sec>