title: Intraoperative guidance in parathyroid surgery using near-infrared fluorescence imaging and low-dose Methylene Blue.
abstract: BACKGROUND
  Identification of diseased and normal parathyroid glands during parathyroid surgery can be challenging. The aim of this study was to assess whether near-infrared (NIR) fluorescence imaging using administration of a low-dose Methylene Blue (MB) at the start of the operation could provide optical guidance during parathyroid surgery and assist in the detection of parathyroid adenomas.
  
  
  METHODS
  Patients diagnosed with primary hyperparathyroidism planned for parathyroidectomy were included. Patients received 0.5 mg/kg MB intravenously directly after start of anesthesia. During the operation, NIR fluorescence imaging was performed to identify parathyroid adenomas. Imaging results were compared with a previous published feasibility study in which 12 patients received MB after intraoperative identification of the adenoma.
  
  
  RESULTS
  A total of 13 patients were included in the current study. In 10 of 12 patients with a histologically proven adenoma, the adenoma was fluorescent. Mean signal to background ratio was 3.1 ± 2.8. Mean diameter of the resected lesions was 17 ± 9 mm (range 5-28 mm). Adenomas could be identified up to 145 minutes after administration, which was the longest timespan until resection. Interestingly, in 3 patients, a total of 6 normal parathyroid glands (median diameter 2.5 mm) with a signal to background ratio of 1.8 ± 0.4 were identified using NIR fluorescence imaging.
  
  
  CONCLUSIONS
  Early administration of low-dose MB provided guidance during parathyroidectomy by identifying both parathyroid adenomas and normal parathyroid glands. In patients in whom difficult identification of the parathyroid adenoma is expected or when normal glands have to be identified, the administration of MB may improve surgical outcome.
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Quirijn R J G
authors.initials: QR
authors.lastname: Tummers
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Abbey
authors.initials: A
authors.lastname: Schepers
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Jaap F
authors.initials: JF
authors.lastname: Hamming
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Kievit
authors.affiliation: Department of Medicine, Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Boston, MA; Department of Radiology, Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Boston, MA; Curadel, LLC, Worcester, MA.
authors.forename: John V
authors.initials: JV
authors.lastname: Frangioni
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Cornelis J H
authors.initials: CJ
authors.lastname: van de Velde
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, the Netherlands. Electronic address: a.l.vahrmeijer@lumc.nl.
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Vahrmeijer
mesh_terms: D000236:Adenoma / Q000175:diagnosis* / Q000601:surgery; D000328:Adult; D000368:Aged; D004396:Coloring Agents / Q000008:administration & dosage; D004334:Drug Administration Schedule; D005260:Female; D005453:Fluorescence; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000150:complications / Q000473:pathology / Q000601:surgery; D008297:Male; D008751:Methylene Blue / Q000008:administration & dosage*; D008875:Middle Aged; D061848:Optical Imaging; D010282:Parathyroid Neoplasms / Q000175:diagnosis* / Q000601:surgery; D016105:Parathyroidectomy; D011300:Preoperative Care; D019265:Spectroscopy, Near-Infrared; D055815:Young Adult
chemical_list: D004396:Coloring Agents; D008751:Methylene Blue