An observational study in Thyroid Surgery, sponsored by Fujian Medical University. Recruiting at 2 sites in China. Per ClinicalTrials.gov, last updated 2025-07-15.
Sponsored by Fujian Medical University · Observational
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.
Post-thyroidectomy hypocalcemia, reported in 5-30 % of cases, is largely attributable to inaccurate assessment of parathyroid perfusion. Conventional intra-operative judgment-based on gland color, capillary bleeding and pulsation-is subjective and non-quantitative. Near-infrared fluorescence imaging with indocyanine green (ICG) allows real-time visualization of tissue perfusion, yet no widely accepted quantitative threshold exists to guide in-situ preservation versus autotransplantation of parathyroid glands.
The PT-ICG study addresses this gap through:
Target population: Patients undergoing unilateral thyroid lobectomy with planned autotransplantation of the ipsilateral inferior parathyroid gland, isolating evaluation to the superior gland.
Pilot phase (n=30): Optimization confirmed an ICG dose of 25 µg/kg and a 60-120 s acquisition window, with the common carotid artery (CCA) providing a stable reference; well-perfused glands exhibited R values \~0.8-3.0.
Derivation phase (n≈120): The relationship between R and 30-min postoperative PTH is modeled; ROC analysis and the Youden index yield R_low and R_high thresholds, internally validated with bootstrap resampling.
Validation phase (n=60): Prospective application of thresholds documents surgeon decisions, postoperative PTH, and hypocalcemia incidence; predictive performance (AUC, sensitivity, specificity) and net clinical benefit (decision-curve analysis) of the R-based strategy are compared with standard clinical judgment.
Sample size and statistics: With an anticipated correlation r≈0.45, α=0.05 (two-sided) and 90 % power, ≥110 patients are required; allowing 10 % attrition, 120-130 will be enrolled.
Data management and safety: REDCap will support double data entry and monitoring; ICG-related adverse events will be recorded; the study adheres to GCP and the Declaration of Helsinki and has received ethics committee approval.
By establishing actionable ICG fluorescence thresholds and a decision algorithm, the study seeks to provide a quantitative tool for real-time intra-operative perfusion assessment, potentially reducing hypocalcemia and informing future multicenter trials.
full SAP available upon request / will be posted as separate document.
98 studies on the registry are indexed under Hypocalcemia; 16 are open to participants now.
This study's planned enrollment of 210 is above the median of 123 across 29 observational studies indexed under Hypocalcemia.
Browse Hypocalcemia studies →Fujian Medical University is the lead sponsor of 148 studies on the registry; 52 are open to participants now.
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Consecutive adult patients undergoing unilateral thyroid lobectomy with planned autotransplantation of the ipsilateral inferior parathyroid gland at a single tertiary endocrine-surgery center; recruitment limited to cases in which the superior parathyroid gland can be preserved in situ and evaluated intra-operatively with indocyanine-green fluorescence quantification.
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Exclusion Criteria:
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An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The model-development cohort consisted of 500 consecutive patients drawn from the Thyroid Surgery Department database of Fujian Medical University Union Hospital (Fuzhou, China)
Diagnostic Test: ntra-operative Indocyanine Green (ICG) Fluorescence Quantification
The external validation cohort comprised 300 patients
Diagnostic Test: 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.
Parathyroid Gland Fluorescence Intensity
Peak fluorescence intensity of the ipsilateral superior parathyroid gland, captured 60 - 120 seconds after a single intravenous bolus of indocyanine green (25 µg/kg).
Time frame: Intra-operative (60 - 120 s post-ICG)
Common Carotid Artery (CCA) Fluorescence Intensity
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.
Time frame: Intra-operative (60 - 120 s post-ICG)
Parathyroid Hormone (PTH) at 30 Minutes post-surgery
PTH concentration (pg/mL) measured by chemiluminescent assay 30 minutes after skin closure, reflecting immediate functional status of the preserved superior parathyroid gland.
Time frame: 30 minutes after surgery
Administered ICG Dose
Total dose of indocyanine green (µg/kg) delivered during the procedure.
Time frame: Intra-operative (time of injection)
PTH at 6 Hours
PTH concentration measured 6 hours after surgery.
Time frame: 6 hours post-surgery
PTH at 2 Weeks
PTH concentration measured 14 ± 2 days after surgery.
Time frame: 2 weeks post-surgery
Plan to share: Undecided
No publications or documents are linked to this record.
Started May 2025 (actual). Primary completion is estimated for Nov 2025, 6 months after the start.
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