Comparative Evaluation of 68Ga-FAPI and 68Ga-DOTATATE PET/CT and PET/MRI in Thyroid Eye Disease

September 16, 2026 updated by: Xiao Chen, Daping Hospital and the Research Institute of Surgery of the Third Military Medical University

Thyroid eye disease is an autoimmune disorder that can cause inflammation and fibrosis of the extraocular muscles and orbital tissues. Accurate assessment of disease activity is important for treatment planning, but commonly used clinical scores and conventional imaging each have limitations.

This prospective single-center cohort study will evaluate two molecular imaging approaches, gallium-68-labeled fibroblast activation protein inhibitor (68Ga-FAPI) PET/CT and PET/MR and gallium-68 DOTATATE somatostatin receptor PET/CT and PET/MR, in adults with thyroid eye disease and in a control group without thyroid-related or orbital disease. The study will compare visual and quantitative imaging findings, including maximum standardized uptake value and target-to-background ratio in the extraocular muscles, and examine their associations with clinical activity score and extraocular muscle thickness. The study aims to characterize the ability of these imaging methods, separately and in combination, to assess thyroid eye disease activity.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This is a prospective, single-center cohort study planned to enroll approximately 50 adults aged 18 to 75 years. The thyroid eye disease cohort will include approximately 30 participants diagnosed according to European Group on Graves' Orbitopathy criteria. The control cohort will include approximately 20 participants without a history of thyroid-related or orbital disease who undergo clinically indicated FAPI or somatostatin receptor PET imaging for another reason; orbital PET/MR acquisition will be added to the existing examination without additional radiation exposure.

Participants in the thyroid eye disease cohort will undergo 68Ga-FAPI and 68Ga-DOTATATE PET/CT and PET/MR imaging within one week. For each tracer, imaging will begin approximately 50 minutes after intravenous administration of 3 to 5 mCi. PET/CT will include a CT acquisition for attenuation correction and anatomic localization followed by three-dimensional PET acquisition of the head for approximately 5 minutes per bed position. PET/MR will include simultaneous PET acquisition and routine MR sequences, including T1-weighted, T2-weighted, and FLAIR imaging. PET images will be reconstructed using an ordered-subset expectation maximization algorithm and fused with CT or MR images.

Nuclear medicine physicians will evaluate images without access to clinical data. Each eye will be visually classified as positive when any extraocular muscle demonstrates uptake greater than background and negative otherwise. For participant-level analysis, a participant will be considered positive when at least one eye is positive. Quantitative analysis will measure maximum standardized uptake value in the superior, medial, lateral, and inferior rectus muscles. A 1-cm region of interest in occipital soft tissue will be used as background. The target-to-background ratio will be calculated as extraocular muscle SUVmax divided by background SUVmax.

Clinical information collected from electronic medical records will include age, sex, disease duration, clinical diagnosis, treatment plan, and Clinical Activity Score. Imaging measures will be compared between groups and modalities and will be examined for associations with Clinical Activity Score and extraocular muscle thickness. Receiver operating characteristic analysis will be used to evaluate diagnostic accuracy.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
50

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • China
    • Chongqing Municipality
      • Chongqing, Chongqing Municipality, China, 400010

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Participants will be selected from adults evaluated in the Department of Nuclear Medicine at the Army Medical Center of PLA between November 2025 and December 2027. The thyroid eye disease cohort will consist of patients meeting European Group on Graves' Orbitopathy diagnostic criteria. The control cohort will consist of patients without thyroid-related or orbital disease who undergo clinically indicated FAPI or somatostatin receptor PET imaging for another reason.

Description

Inclusion Criteria:

  • For the thyroid eye disease cohort: diagnosis of thyroid eye disease according to European Group on Graves' Orbitopathy criteria.
  • For the thyroid eye disease cohort: scheduled to undergo 68Ga-FAPI PET/CT and PET/MR and 68Ga-DOTATATE PET/CT and PET/MR within one week.
  • For the control cohort: clinically recommended to undergo FAPI or somatostatin receptor PET imaging for another reason, with no history of thyroid-related disease or orbital disease; orbital PET/MR is added to the existing examination without additional radiation exposure.

Exclusion Criteria:

  • Previous bilateral orbital surgery.
  • Treatment with glucocorticoids, monoclonal antibodies, or radiotherapy within the previous month.
  • Inability to remain supine.
  • Contraindication to MRI, including incompatible metallic implants or claustrophobia.
  • Planning pregnancy, currently pregnant, or breastfeeding.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: COHORT
  • Time Perspectives: PROSPECTIVE

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Group 1 Thyroid Eye Disease Cohort

Adults diagnosed with thyroid eye disease according to European Group on Graves' Orbitopathy criteria. Participants undergo 68Ga-FAPI and 68Ga-DOTATATE PET/CT and PET/MR imaging within one week.
Diagnostic test: 68Ga-FAPI PET/CT and PET/MR Imaging

Participants receive 3 to 5 mCi of 68Ga-FAPI intravenously. PET/CT and PET/MR imaging of the head and orbits is performed approximately 50 minutes after injection, with PET acquisition of approximately 5 minutes per bed position. PET/MR includes routine T1-weighted, T2-weighted, and FLAIR sequences. The exact FAPI compound should be added if specified by the radiopharmacy documentation.

Required confirmation: the protocol does not identify the specific FAPI compound, such as FAPI-04.

Diagnostic test: 68Ga-DOTATATE PET/CT and PET/MR Imaging

Participants receive 3 to 5 mCi of 68Ga-DOTATATE intravenously. PET/CT and PET/MR imaging of the head and orbits is performed approximately 50 minutes after injection, with PET acquisition of approximately 5 minutes per bed position. PET/MR includes routine T1-weighted, T2-weighted, and FLAIR sequences.
Group 2 Control Cohort

Adults without a history of thyroid-related or orbital disease who undergo clinically indicated FAPI or somatostatin receptor PET imaging for another reason. Orbital PET/MR acquisition is added to the existing examination without additional radiation exposure.
Diagnostic test: 68Ga-FAPI PET/CT and PET/MR Imaging

Participants receive 3 to 5 mCi of 68Ga-FAPI intravenously. PET/CT and PET/MR imaging of the head and orbits is performed approximately 50 minutes after injection, with PET acquisition of approximately 5 minutes per bed position. PET/MR includes routine T1-weighted, T2-weighted, and FLAIR sequences. The exact FAPI compound should be added if specified by the radiopharmacy documentation.

Required confirmation: the protocol does not identify the specific FAPI compound, such as FAPI-04.

Diagnostic test: 68Ga-DOTATATE PET/CT and PET/MR Imaging

Participants receive 3 to 5 mCi of 68Ga-DOTATATE intravenously. PET/CT and PET/MR imaging of the head and orbits is performed approximately 50 minutes after injection, with PET acquisition of approximately 5 minutes per bed position. PET/MR includes routine T1-weighted, T2-weighted, and FLAIR sequences.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Extraocular Muscle SUVmax on 68Ga-FAPI and 68Ga-DOTATATE PET Imaging
Time Frame: At each imaging examination performed within the protocol-defined 1-week imaging period

Maximum standardized uptake value will be measured separately in the superior, medial, lateral, and inferior rectus muscles on PET/CT and PET/MR images for each tracer. Values will be summarized by tracer, imaging platform, eye, and participant group.
At each imaging examination performed within the protocol-defined 1-week imaging period
Extraocular Muscle Target-to-Background Ratio on 68Ga-FAPI and 68Ga-DOTATATE PET Imaging
Time Frame: At each imaging examination performed within the protocol-defined 1-week imaging period

For each extraocular muscle, target-to-background ratio will be calculated as extraocular muscle SUVmax divided by background SUVmax measured using a 1-cm region of interest in occipital soft tissue. Values will be summarized by tracer, imaging platform, eye, and participant group.
At each imaging examination performed within the protocol-defined 1-week imaging period

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Diagnostic Accuracy for Thyroid Eye Disease Activity
Time Frame: At completion of imaging and clinical activity assessment within the protocol-defined 1-week period

Receiver operating characteristic curves will be used to estimate the area under the curve for quantitative 68Ga-FAPI and 68Ga-DOTATATE PET/CT and PET/MR measures in relation to clinically defined thyroid eye disease activity.

Required confirmation: specify the reference standard and exact Clinical Activity Score threshold used to define active disease before submission.
At completion of imaging and clinical activity assessment within the protocol-defined 1-week period
Association Between PET Uptake Measures and Clinical Activity Score
Time Frame: At completion of imaging and Clinical Activity Score assessment within the protocol-defined 1-week period

Pearson correlation coefficients will be used to assess associations of extraocular muscle SUVmax and target-to-background ratio with Clinical Activity Score.
At completion of imaging and Clinical Activity Score assessment within the protocol-defined 1-week period
Association Between PET Uptake Measures and Extraocular Muscle Thickness
Time Frame: At each imaging examination performed within the protocol-defined 1-week imaging period

Pearson correlation coefficients will be used to assess associations of extraocular muscle SUVmax and target-to-background ratio with extraocular muscle thickness measured on anatomic imaging.

Required confirmation: specify the sequence, measurement plane, muscle-specific rule, and unit for extraocular muscle thickness.
At each imaging examination performed within the protocol-defined 1-week imaging period

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Visual Positivity of Extraocular Muscle Uptake
Time Frame: At each imaging examination performed within the protocol-defined 1-week imaging period

Each eye will be classified as positive when any extraocular muscle demonstrates 68Ga-FAPI or 68Ga-DOTATATE uptake greater than background and negative otherwise. At participant level, a participant will be classified as positive when at least one eye is positive. Positivity will be compared between imaging approaches using categorical analyses.
At each imaging examination performed within the protocol-defined 1-week imaging period

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Daping Hospital and the Research Institute of Surgery of the Third Military Medical University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 14, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 16, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 16, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 23, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 23, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 16, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2025480

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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