Near Infrared Autofluorescence Imaging in Minimally-Invasive Video-Assisted Parathyroidectomy (NIRAF MIVAP Study) (NIRAF MIVAP)

Assessing the Feasibility of Near Infrared Autofluorescence Imaging in Minimally-Invasive Video-Assisted Parathyroidectomy and the Autofluorescence Signature of Parathyroid Adenomas

The role of near-infrared autofluorescence (NIRAF)-imaging as an adjunct in thyroid surgery is well established. However, its diagnostic role in hyperparathyroidism surgery is yet to be defined due to the lack of consensus regarding the autofluorescence (AF) pattern of pathological parathyroid glands. Furthermore, its utility via a direct minimal access has not been assessed.

To assess the AF pattern of parathyroid adenomas (PAs) utilizing NIRAF-imaging in minimally invasive video-assisted parathyroidectomy (MIVAP).

The clinical records of patients who underwent MIVAP for hyperparathyroidism between February and October 2024 were retrospectively reviewed. The primary endpoint was to assess the AF pattern of PAs. Secondary endpoints included the feasibility of applying NIRAF imaging in MIVAP and whether certain AF patterns of PAs correlated with cell type, size, and/or location. Furthermore, operative-time and cost implications were assessed.

Study Overview

• Status: Completed
• Conditions: Primary Hyperparathyroidism Due to Adenoma
• Intervention / Treatment: Procedure: parathyroidectomy

Detailed Description

Native fluorescence or autofluorescence (AF) is defined as the emission of light by a naturally occurring fluorophore, on excitation by incident light of a specific wavelength. Accordingly, fluorescence produced by an endogenous fluorophore differs from that resulting from the application of a synthetic fluorescent marker and is, therefore, considered "contrast-free fluorescence." Maximal AF from both thyroid and parathyroid tissue occurs at the near-infrared spectrum (820-830 nm wavelength) with parathyroid tissue maximal emission intensity being 2-20 times greater than that of thyroid tissue and lasts at least for one hour in vivo. This is probably attributed to that the fluorophore assumed to be responsible for thyroid and parathyroid tissue AF is the calcium-sensing receptor that is present in parafollicular cells (C-cells), but to a much higher extent in parathyroid tissue. This allows for PTGs to be visualized as bright spots on a background of low fluorescence (thyroid gland). The fact that AF persists for at least an hour even after gland devascularization or unintentional resection, implies that NIRAF cannot confirm PTG viability. Viability depends on adequate tissue perfusion. This in turn requires assessing tissue vascularity using AF from a synthetic fluorescent marker such as indocyanine green (ICG); the concept of contrast-enhanced AF rather than contrast-free AF.

The property of AF in a tissue depends on the concentration of the endogenous fluorophore and whether it is affected by a pathological process. Hence, its application in clinical practice allowing it to serve as an optical biopsy (a point detection tool that provides real-time, non-invasive diagnostic information without physically exciting tissue). This might explain why unlike normal parathyroid tissue, parathyroid adenomas (PAs) demonstrate a heterogenous pattern of AF. Demarchi et al. reported that most PAs in their study appeared significantly less autofluorescent than the rim of compressed normal parathyroid tissue (at the periphery of a PA) that appeared as bright cap. This was referred to as cap AF. Nevertheless, no noticeable differences in the pattern of AF between adenomatous, hyperplastic, and normal PTGs were observed by others.

Minimally invasive video-assisted parathyroidectomy (MIVAP) is one of the most popular targeted parathyroid procedures performed for primary hyperparathyroidism. It has been demonstrated that the advantages offered by MIVAP enables it to overcome the limitations of other targeted parathyroid procedures. Allowing for full neck exploration and/or performing a concomitant thyroid procedure without the need to convert to a standard cervicotomy.

The objective of this study was to assess the feasibility of applying NIRAF-imaging via a limited direct access and the potential patterns of AF (AF signature) of PAs on contrast-free NIRAF-based imaging, and whether specific patterns of AF correlated with factors intrinsic to PAs such as the dominant cell type of a PA, its size and/or location. The additional operative time, and cost conferred using this technology were also evaluated

• Study Type: Observational
• Enrollment (Actual): 24

Contacts and Locations

Study Locations

• Jordan
  • Zarqa, Jordan
    • the Hashemite Univesity

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

patients with parathyroid adenoma undergoing surgery and age >18 years old

Description

Inclusion Criteria:

• patients diagnosed with parathyroid adenoma undergoing surgery

Exclusion Criteria:

• patients <18 years old

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
patterns of autofluorescence in parathyroid adenomas	during surgery

Secondary Outcome Measures

Outcome Measure	Time Frame
specific autofluorescence patterns correlated with the dominant cell type of a parathyroid adenoma	during surgery
specific autofluorescence patterns correlated with adenoma size	during surgery
specific autofluorescence patterns correlated with adenoma location	during surgery

Collaborators and Investigators

• Sponsor: Aristotle University Of Thessaloniki
• Collaborators: The Hashemite University

Study record dates

Study Major Dates

• Study Start (Actual): September 20, 2024
• Primary Completion (Actual): October 15, 2024
• Study Completion (Actual): October 20, 2024

Study Registration Dates

• First Submitted: November 3, 2024
• First Submitted That Met QC Criteria: January 13, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 13, 2025
• Last Verified: November 1, 2024

More Information

Terms related to this study

• Keywords: primary hyperparathyroidism; near-infrared autofluorescence; parathyroid adenoma; minimally invasive parathyroidectomy
• Additional Relevant MeSH Terms: Endocrine System Diseases; Neoplasms; Neoplasms by Histologic Type; Neoplasms, Glandular and Epithelial; Parathyroid Diseases; Hyperparathyroidism; Hyperparathyroidism, Primary; Adenoma
• Other Study ID Numbers: NIRAF MIVAP study

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No