title: Intraoperative Near-Infrared Optical Imaging Can Localize Gadolinium-Enhancing Gliomas During Surgery.
abstract: Although real-time localization of gliomas has improved with intraoperative image guidance systems, these tools are limited by brain shift, surgical cavity deformation, and expense.
  
  
  
  To propose a novel method to perform near-infrared (NIR) imaging during glioma resections based on preclinical and clinical investigations, in order to localize tumors and to potentially identify residual disease.
  
  
  
  Fifteen patients were identified and administered a Food and Drug Administration-approved, NIR contrast agent (Second Window indocyanine green [ICG], 5 mg/kg) before surgical resection. An NIR camera was utilized to localize the tumor before resection and to visualize surgical margins following resection. Neuropathology and magnetic resonance imaging data were used to assess the accuracy and precision of NIR fluorescence in identifying tumor tissue.
  
  
  
  NIR visualization of 15 gliomas (10 glioblastoma multiforme, 1 anaplastic astrocytoma, 2 low-grade astrocytoma, 1 juvenile pilocytic astrocytoma, and 1 ganglioglioma) was performed 22.7 hours (mean) after intravenous injection of ICG. During surgery, 12 of 15 tumors were visualized with the NIR camera. The mean signal-to-background ratio was 9.5 ± 0.8 and fluorescence was noted through the dura to a maximum parenchymal depth of 13 mm. The best predictor of positive fluorescence was enhancement on T1-weighted imaging; this correlated with signal-to-background ratio (P = .03). Nonenhancing tumors did not demonstrate NIR fluorescence. Using pathology as the gold standard, the technique demonstrated a sensitivity of 98% and specificity of 45% to identify tumor in gadolinium-enhancing specimens (n = 71).
  
  
  
  With the use of Second Window ICG, gadolinium-enhancing tumors can be localized through brain parenchyma intraoperatively. Its utility for margin detection is promising but limited by lower specificity.
  
  
  
  5-ALA, 5-aminolevulinic acidEPR, enhanced permeability and retentionFDA, Food and Drug AdministrationGBM, glioblastomaICG, indocyanine greenNIR, near-infraredNPV, negative predictive valuePPV, positive predictive valueROC, receiver operating characteristicROI, region of interestSBR, signal-to-background ratioWHO, World Health Organization.
authors.affiliation: *Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania; ‡Department of Pathology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania; §Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania; ¶Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: John Y K
authors.initials: JY
authors.lastname: Lee
authors.forename: Jayesh P
authors.initials: JP
authors.lastname: Thawani
authors.forename: John
authors.initials: J
authors.lastname: Pierce
authors.forename: Ryan
authors.initials: R
authors.lastname: Zeh
authors.forename: Maria
authors.initials: M
authors.lastname: Martinez-Lage
authors.forename: Michelle
authors.initials: M
authors.lastname: Chanin
authors.forename: Ollin
authors.initials: O
authors.lastname: Venegas
authors.forename: Sarah
authors.initials: S
authors.lastname: Nims
authors.forename: Kim
authors.initials: K
authors.lastname: Learned
authors.forename: Jane
authors.initials: J
authors.lastname: Keating
authors.forename: Sunil
authors.initials: S
authors.lastname: Singhal
mesh_terms: D000328:Adult; D000622:Aminolevulinic Acid; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D004396:Coloring Agents; D003287:Contrast Media; D005260:Female; D005453:Fluorescence; D005682:Gadolinium; D018303:Ganglioglioma / Q000473:pathology; D005910:Glioma / Q000000981:diagnostic imaging* / Q000601:surgery*; D006801:Humans; D007208:Indocyanine Green; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D061848:Optical Imaging; D019265:Spectroscopy, Near-Infrared
chemical_list: D004396:Coloring Agents; D003287:Contrast Media; D000622:Aminolevulinic Acid; D005682:Gadolinium; D007208:Indocyanine Green