ntra-operative Indocyanine Green (ICG) Fluorescence Quantification
ntra-operative Indocyanine Green (ICG) Fluorescence Quantification: After a single intravenous bolus of indocyanine green (25 µg/kg), a near-infrared sensor records raw fluorescence intensity from the superior parathyroid gland and the ipsilateral common carotid artery at 60-120 seconds. No images are stored; only peak intensity values are logged to calculate the perfusion ratio R = PTG / CCA. The measurement is observational, adds ≤2 minutes to operative time, and involves no therapeutic intent.
Study summary
This single-center, prospective, three-phase observational cohort quantifies the relationship between indocyanine green (ICG) fluorescence and early parathyroid function. Adult patients scheduled for unilateral thyroid lobectomy with autotransplantation of the ipsilateral inferior parathyroid gland are enrolled. After intravenous ICG 25 µg/kg, peak fluorescence of the superior parathyroid gland and the common carotid artery (CCA) is recorded at 60-120 seconds to calculate the ratio R = PTG/CCA. Serum parathyroid hormone (PTH) is measured 30 minutes post-operatively. A derivation cohort (\~120 patients) generates R-based thresholds for in-situ preservation versus autotransplantation, which are prospectively validated in an independent cohort (60 patients) together with decision-curve analysis of clinical net benefit.
Eligibility
Sex
ALL
Min age
—
Max age
—
Healthy volunteers
No
Inclusion Criteria:
* Scheduled for unilateral thyroid lobectomy plus central (VI-level) lymph-node dissection.
* Intra-operative findings consistent with:
* Complete identification and in-situ preservation of the ipsilateral superior parathyroid gland;
* Complete identification and autotransplantation of the ipsilateral inferior parathyroid gland.
* Serum 25-hydroxy-vitamin D ≥ 30 ng/mL at baseline; patients below this level may be enrolled after standardized vitamin-D and calcium supplementation with re-test confirming ≥ 30 ng/mL.
* Surgery and all postoperative follow-up performed at the study center.
* Able and willing to provide written informed consent.
Exclusion Criteria:
* Prior surgery on the thyroid or parathyroid glands.
* Severe hepatic or renal impairment, or other serious metabolic bone disease.
* Pregnancy or lactation.
* Known hypersensitivity to indocyanine green or iodine-containing compounds.
* Inability or unwillingness to comply with postoperative visits and blood testing.
Primary outcome measure(s)
Parathyroid Gland Fluorescence Intensity — Intra-operative (60 - 120 s post-ICG) Peak fluorescence intensity of the ipsilateral superior parathyroid gland, captured 60 - 120 seconds after a single intravenous bolus of indocyanine green (25 µg/kg).
Common Carotid Artery (CCA) Fluorescence Intensity — Intra-operative (60 - 120 s post-ICG) Peak fluorescence intensity of the ipsilateral common carotid artery recorded in the same 60 - 120 second window; serves as the reference signal for perfusion ratio calculations.
Parathyroid Hormone (PTH) at 30 Minutes post-surgery — 30 minutes after surgery PTH concentration (pg/mL) measured by chemiluminescent assay 30 minutes after skin closure, reflecting immediate functional status of the preserved superior parathyroid gland.
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
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