Fig. 2.

Ex vivo fluorescence molecular imaging analyses. A Using the standard fluorescence analysis, H&E segmentation of SNIP and uninvolved tissue are superimposed on the fluorescence image of the corresponding FFPE block. This method renders one value of both SNIP (blue ROI) and uninvolved tissue (orange ROI) per FFPE block, in which variability in fluorescence intensity is undesirably averaged. B In the fluorescence grid analysis, a 25 × 25 pixel grid is rendered on the fluorescence image. Using H&E segmentation as a reference, each square is scored as SNIP or uninvolved tissue, excluding squares that do not completely comprise tissue. Mean fluorescence intensity is calculated per square, resulting in multiple data points that demonstrate variability in signal. Abbreviations: FFPE, formalin-fixed, paraffin-embedded; SNIP, sinonasal inverted papilloma; TBR, target-to-background ratio