Table 1.
Pertinent results of abdominal ultrasonography (US), abdominal CT angiography, surgical findings (including both visible light and NIR), and surgical procedures with World Health Organization TNM stage based on histology results for each dog. [17] Pancreatic mass locations: L (left lobe with further location not specified), LD (distal left lobe), LP (proximal left lobe), B (body), R (right lobe with further location not specified), RP (proximal right lobe), RD (distal right lobe).
Table 2.
ImageJ analysis results of fluorescence intensity and IHC results of relevant excised tissues for each dog. The ratio of IHC positivity (IHCr) between pancreatic mass and adjacent non-neoplastic pancreas has also been provided for each dog. When multiple IHC slides were available for a given tissue type, the average positivity for the tissue type in the dog was recorded. Histologic evidence of metastasis within the sample is denoted (M). All findings (including fluorescence intensity and standard deviation) are averages of measurements performed in triplicate for each tissue type. Gain settings are reported for each recording. All provided measurements were obtained from in situ images unless otherwise noted.
Fig 1.
Intraoperative image with visible light alone (A), NIR alone (B), and an overlay of NIR findings on visible light (C) of the right pancreatic lobe from Dog 4 (the same dog with IHC depicted in Fig 4).
All tissues aside from the pancreas and mesoduodenum have been covered with laparotomy sponges. This dog had a small pancreatic nodule (denoted by white arrows) that was not definitively identified upon initial visualization or palpation of the pancreas but was identified following application of NIR imaging due to a focal region of enhanced fluorescence intensity relative to the surrounding pancreas.
Fig 2.
Intraoperative images with visible light alone (A and D), NIR alone (B and E), and an overlay of NIR findings on visible light (C and F) of the pancreatic mass from Dog 3 (A, B, and C) and Dog 2 (D, E, and F), respectively.
The blue arrow points to the pancreatic mass, and the yellow arrow points to the adjacent grossly normal pancreas. The green arrow in Dog 2 images points to a colonic lymph node. In images B, C, E, and F, enhanced fluorescence of the pancreatic tumor relative to grossly normal adjacent pancreas is evident as is generalized background fluorescence of the adjacent gastrointestinal tissues (Dogs 3 and 2) and colonic lymph node (Dog 2). Dogs 3 and 2 had the greatest and lowest TBRs, respectively, such that these images depict representative intraoperative findings of the range of fluorescence discrepancy between pancreatic tumors and the adjacent pancreas in dogs of this study.
Fig 3.
Images of the partial pancreatectomy sample in Dog 5.
A) Ex vivo image of left partial pancreatectomy in visible light; the margins of excision have been marked with ink (yellow), and the margins of enhanced fluorescence intensity have been marked with suture. B) Ex vivo image of left partial pancreatectomy with NIR overlay on visible light, demonstrating the suture placement relative to fluorescence. C) Formalin-fixed paraffin embedded slide (0.5x) stained with hematoxylin/eosin of the pancreatic lesion, which has been trimmed through the suture sites peripherally; the scale bar represents 4 mm. Neoplastic cells extend to within less than 1 mm of the capsular connective tissue in the sutured sites. (Sutures were removed prior to sectioning.).
Fig 4.
Pancreatic tumor and surrounding non-neoplastic pancreas in Dog 4.
Top panel: Formalin-fixed paraffin embedded slide (0.9x) stained with cathepsin B antibody for IHC analysis; the scale bar represents 2 mm. Bottom panel: A close-up image captured at the junction of tumor and normal pancreas shows significantly higher levels of cathepsin B immunoreactivity in the neoplastic tissue; the scale bar represents 100 μm.