title: Intraoperative near-infrared autofluorescence imaging of parathyroid glands.
abstract: To identify parathyroid glands intraoperatively by exposing their autofluorescence using near-infrared light.
  
  
  
  Fluorescence imaging was carried out during minimally invasive and open parathyroid and thyroid surgery. After identification, the parathyroid glands as well as the surrounding tissue were exposed to near-infrared (NIR) light with a wavelength of 690-770 nm using a modified Karl Storz near-infrared/indocyanine green (NIR/ICG) endoscopic system. Parathyroid tissue was expected to show near-infrared autofluorescence, captured in the blue channel of the camera. Whenever possible the visual identification of parathyroid tissue was confirmed histologically.
  
  
  
  In preliminary investigations, using the original NIR/ICG endoscopic system we noticed considerable interference of light in the blue channel overlying the autofluorescence. Therefore, we modified the light source by interposing additional filters. In a second series, we investigated 35 parathyroid glands from 25 patients. Twenty-seven glands were identified correctly based on NIR autofluorescence. Regarding the extent of autofluorescence, there were no noticeable differences between parathyroid adenomas, hyperplasia and normal parathyroid glands. In contrast, thyroid tissue, lymph nodes and adipose tissue revealed no substantial autofluorescence.
  
  
  
  Parathyroid tissue is characterized by showing autofluorescence in the near-infrared spectrum. This effect can be used to distinguish parathyroid glands from other cervical tissue entities.
authors.affiliation: Department of Surgery, Ludwig Maximilians University Munich, Innenstadt Medical Campus, Nussbaumstrasse 20, 80336, Munich, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Ladurner
authors.affiliation: Department of Surgery, Ludwig Maximilians University Munich, Innenstadt Medical Campus, Nussbaumstrasse 20, 80336, Munich, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Sommerey
authors.affiliation: Department of Surgery, Ludwig Maximilians University Munich, Innenstadt Medical Campus, Nussbaumstrasse 20, 80336, Munich, Germany.
authors.forename: Nora Al
authors.initials: NA
authors.lastname: Arabi
authors.affiliation: Department of Surgery, Ludwig Maximilians University Munich, Innenstadt Medical Campus, Nussbaumstrasse 20, 80336, Munich, Germany. Klaus.Hallfeldt@med.uni-muenchen.de.
authors.forename: Klaus K J
authors.initials: KKJ
authors.lastname: Hallfeldt
authors.affiliation: Laser-Research Laboratory, LIFE-Center, Ludwig Maximilians University Munich, Grosshadern Medical Campus, Feodor-Lynen-Str. 19, 81377, Munich, Germany.
authors.forename: Herbert
authors.initials: H
authors.lastname: Stepp
authors.affiliation: Department of Obstetrics and Gynecology, Ludwig Maximilians University Munich, Grosshadern Medical Campus, Marchioninistr. 15, 81377, Munich, Germany.
authors.forename: Julia K S
authors.initials: JKS
authors.lastname: Gallwas
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging* / Q000601:surgery; D004724:Endoscopy; D005453:Fluorescence; D006801:Humans; D007208:Indocyanine Green; D007430:Intraoperative Care; D008198:Lymph Nodes; D061848:Optical Imaging / Q000379:methods*; D010280:Parathyroid Glands / Q000000981:diagnostic imaging* / Q000601:surgery; D010282:Parathyroid Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D011446:Prospective Studies; D013961:Thyroid Gland / Q000601:surgery*
chemical_list: D007208:Indocyanine Green
keywords: Autofluorescence; Near-infrared light; Parathyroid glands; Parathyroidectomy