title: Indocyanine green fluorescence angiography for quantitative evaluation of in situ parathyroid gland perfusion and function after total thyroidectomy.
abstract: Because the fluorescent light intensity on an indocyanine green fluorescence angiography reflects the blood perfusion within a focused area, the fluorescent light intensity in the remaining in situ parathyroid glands may predict postoperative hypocalcemia risk after total thyroidectomy.
  
  
  
  Seventy patients underwent intraoperative indocyanine green fluorescence angiography after total thyroidectomy. Any parathyroid glands with a vascular pedicle was left in situ while any parathyroid glands without pedicle or inadvertently removed was autotransplanted. After total thyroidectomy, an intravenous 2.5 mg indocyanine green fluorescence angiography was given and real-time fluorescent images of the thyroid bed were recorded using the SPY imaging system (Novadaq, Ontario, Canada). The fluorescent light intensity of each indocyanine green fluorescence angiography as well as the average and greatest fluorescent light intensity in each patient were calculated. Postoperative hypocalcemia was defined as adjusted calcium <2.00 mmol/L within 24 hours.
  
  
  
  The fluorescent light intensity between discolored and normal-looking indocyanine green fluorescence angiographies was similar (P = .479). No patients with a greatest fluorescent light intensity >150% developed postoperative hypocalcemia while 9 (81.8%) patients with a greatest fluorescent light intensity ≤150% did. Similarly, no patients with an average fluorescent light intensity >109% developed PH while 9 (30%) with an average fluorescent light intensity ≤109% did. The greatest fluorescent light intensity was more predictive than day-0 postoperative hypocalcemia (P = .027) and % PTH drop day-0 to 1 (P < .001).
  
  
  
  Indocyanine green fluorescence angiography is a promising operative adjunct in determining residual parathyroid glands function and predicting postoperative hypocalcemia risk after total thyroidectomy.
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China. Electronic address: blang@hku.hk.
authors.forename: Brian Hung-Hin
authors.initials: BH
authors.lastname: Lang
authors.affiliation: Department of Family Medicine and Primary Care, University of Hong Kong, 3/F Ap Lei Chau Clinic, Ap Lei Chau, Hong Kong SAR, China.
authors.forename: Carlos K H
authors.initials: CK
authors.lastname: Wong
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Hing Tsun
authors.initials: HT
authors.lastname: Hung
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Kai Pun
authors.initials: KP
authors.lastname: Wong
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Ka Lun
authors.initials: KL
authors.lastname: Mak
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Kin Bun
authors.initials: KB
authors.lastname: Au
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005069:Evaluation Studies as Topic; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D005500:Follow-Up Studies; D006801:Humans; D006980:Hyperthyroidism / Q000175:diagnosis / Q000601:surgery; D006996:Hypocalcemia / Q000517:prevention & control; D007011:Hypoparathyroidism / Q000175:diagnosis / Q000517:prevention & control*; D007208:Indocyanine Green; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D010280:Parathyroid Glands / Q000000981:diagnostic imaging*; D061214:Patient Safety / Q000706:statistics & numerical data; D011182:Postoperative Care / Q000379:methods; D011237:Predictive Value of Tests; D013965:Thyroidectomy / Q000009:adverse effects / Q000379:methods*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D007208:Indocyanine Green