ClinicalTrials.gov record NCT04246437

[18F]F-DOPA Imaging in Patients With Autonomic Failure

Record copied from ClinicalTrials.gov: Oct 10, 2026AI summaries generated: Sep 7, 2026

[18F]F-DOPA Imaging in Patients With Autonomic Failure

StatusRecruitingThe study is currently enrolling participants. Only the study team can say whether a particular person can join.
Study typeInterventionalA study in which researchers assign participants to one or more interventions, such as a drug, procedure, device, behavioural programme or other approach, to measure their effects.
PhasePhase 1An early-stage study, usually small, mainly to check safety, side effects and how much of a treatment can be given. Whether it works is not the main question yet.
Healthy volunteersAcceptedPeople who do not have the condition being studied who are allowed to take part. Some studies include both people with the condition and healthy volunteers; others may enrol only healthy volunteers.
Age18 years old and older
SexAll
LocationUnited States
AI summaryWhat this study is about, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

This Phase 1 interventional study uses [18F]F-DOPA PET scans to measure presynaptic dopamine production in people with autonomic failure (including Pure Autonomic Failure) and related synucleinopathies, plus healthy adults. Participants receive oral carbidopa and entacapone before a single [18F]F-DOPA PET scan with serial imaging for about 95 minutes. The study compares tracer uptake in brain regions such as the substantia nigra, locus coeruleus, and brainstem.

What it is studying. The study tests whether [18F]F-DOPA PET imaging can detect differences in presynaptic dopamine production in key brain regions across people with Pure Autonomic Failure, Parkinson disease, Multiple System Atrophy, Dementia with Lewy Bodies, and healthy adults, and whether those patterns relate to conversion from peripheral to central nervous system disease.

What the researchers hope to learn. To identify patterns of dopamine production in the substantia nigra, locus coeruleus, and brainstem that differ between Pure Autonomic Failure, Parkinson disease, Multiple System Atrophy, and Dementia with Lewy Bodies; and to evaluate whether [18F]F-DOPA uptake could serve as a biomarker to predict conversion from peripheral autonomic disease to central synucleinopathies.

What this study is about

The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.

Alpha-synucleinopathies refer to age-related neurodegenerative and dementing disorders, characterized by the accumulation of alpha-synuclein in neurons and/or glia. The anatomical location of alpha-synuclein inclusions (Lewy Bodies) and the pattern of progressive neuronal death (e.g. caudal to rostral brainstem) give rise to distinct neurological phenotypes, including Parkinson's disease (PD), Multiple System Atrophy (MSA), Dementia with Lewy Bodies (DLB). Common to these disorders are the involvement of the central and peripheral autonomic nervous system, where Pure Autonomic Failure (PAF) is thought (a) to be restricted to the peripheral autonomic system, and (b) a clinical risk factor for the development of a central synucleinopathy, and (c) an ideal model to assess biomarkers that predict phenoconversion to PD, MSA, or DLB. Such biomarkers would aid in clinical trial inclusion criteria to ensure assessments of disease- modifying strategies to, delay, or halt, the neurodegenerative process. One of these biomarkers may be related to the neurotransmitter dopamine (DA) and related changes in the substantia nigra (SN) and brainstem. [18F]F-DOPA is a radiolabeled substrate for aromatic amino acid decarboxylase (AAADC), an enzyme involved in the production of dopamine. Use of this radiolabeled substrate in positron emission tomography (PET) may provide insight to changes in monoamine production and how they relate to specific phenoconversions in PAF patients. Overall, this study aims to identify changes in dopamine production in key regions including the SN, locus coeruleus, and brainstem to distinguish between patients with PD, MSA, and DLB, which may provide vital information to predict conversion from peripheral to central nervous system disease.

Interventions being studied

Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.

Drug
  • [18F]FDOPA
  • Carbidopa 200mg oral dose
  • Entacapone 400mg oral dose

Eligibility

The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.

Inclusion criteria

  • Patients with a diagnosis if pure autonomic failure
  • Patients with autonomic failure and possible PD, MSA, or DLB
  • Healthy adults aged 18 and above
  • Clinical exam confirming clinical designation

Exclusion criteria

  • Subjects who have any type of bioimplant activated by mechanical, electronic, or magnetic means (e.g., cochlear implants, pacemakers, neurostimulators, biostimulators, electronic infusion pumps, etc.), because such devices may be displaced or malfunction.
  • Subjects who have any type of ferromagnetic bioimplant that could potentially be displaced.
  • Subjects who have cerebral aneurysm clips.
  • Subjects who may have shrapnel imbedded in their bodies (such as from war wounds), metal workers and machinists (potential for metallic fragments in or near the eyes).
  • Subjects who are pregnant, because the effects of high field MRI on fetuses are not yet known.
  • Minors (younger than 18 years)
  • Also excluded are subjects incapable of giving informed written consent:
  • Subjects who cannot adhere to the experimental protocols for any reason, or have an inability to communicate with the researcher.
  • Subjects who have limited mental ability to give informed consent, mentally retarded, altered mental status, mental disability, confusion, or psychiatric disorders.
  • Prisoners

Study description and what participation involves

The registry record has no detailed description beyond the summary above.

AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

After screening and a confirming clinical exam, participants receive oral carbidopa 200 mg and entacapone 400 mg about 30 minutes before imaging. You will be given an injection of about 6–8 mCi of [18F]F‑DOPA and undergo serial PET brain scans starting with the injection and continuing for approximately 95 minutes. The visit requires lying still in the scanner during imaging; the registry does not list other procedures.

How the study is structured. Interventional Phase 1, single-group, open-label study. All participants receive oral carbidopa and entacapone about 30 minutes before a slow intravenous bolus of [18F]F-DOPA, then undergo serial PET imaging for roughly 95 minutes to measure tracer uptake in targeted brain regions.

Questions you could ask

These questions are suggestions for a conversation with the study team or your own clinician, not advice.

  • This is an early-phase study, mainly about safety and dose. What is already known about this treatment?
  • The listed sites are in United States. Is any of them reachable for me, and does the study help with travel?
  • Which of the eligibility criteria would need to be checked with tests before I could join?

More on multiple system atrophy

Clinical trials76 trials listed for multiple system atrophyEvery trial the registry lists for multiple system atrophy, with recruitment status, phase and sites, updated from ClinicalTrials.gov.See all trials →Research updatesWhat changed in multiple system atrophy researchLatest monthly update: September 2026. Includes: Tube feeding. New research summarized each month in plain language, with links to every source paper.Read the latest update →

Important dates

Study start
Feb 4, 2020
Primary completion
Feb 1, 2027 (estimated)
Study completion
Feb 1, 2027 (estimated)
Target enrollment
40 participants (estimated)
Last updated on registry
Mar 16, 2026
Data verified
Oct 10, 2026

Sponsor and research team

The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.

Lead sponsor
Daniel Claassen

Central study contact

If you're interested in participating, the central contact can answer general questions about the study — including eligibility requirements and how to find a recruiting site near you. Actual eligibility is determined by the site's medical team.

Participating sites (1)

  • Vanderbilt University Medical CenterRecruiting

    Nashville, Tennessee, 37212 · United States

Terms used on this page · explanations by MedicalUpdates.ai

biomarkers
Something measurable in the body, such as a blood test result or an imaging finding, that indicates how a condition or treatment is behaving.
inclusion criteria
The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
positron emission tomography
A scan in which a small amount of a radioactive tracer is injected so that activity in tissues can be seen. Often combined with a CT or MRI scan.
MRI
A scan that uses magnets and radio waves, not X-rays, to make detailed pictures of the inside of the body. Some implants and metal objects mean a person cannot have one.
informed consent
The process of explaining a study, including its risks and what participation involves, so that a person can decide freely whether to take part. Consent is usually documented in writing, and a participant can choose to leave the study later.
Exclusion Criteria
The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.

The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.

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