In Vivo Imaging of the Olfactory Epithelium Using Confocal Laser Endomicroscopy

August 31, 2026 updated by: Ryan.E.Little, Dartmouth-Hitchcock Medical Center

In Vivo Imaging of Olfactory Epithelium in Humans With Olfactory Impairment Using Confocal Laser Endomicroscopy

This research is being done to better characterize the part of the nose that helps people smell. Currently, the only ways to study smell loss mostly rely on how people report it, rather than being able to see the underlying structures directly. In this study, the team will use a special microscope (Confocal Laser Endomicroscopy (CLE)), originally developed for brain tissue, to look at the part of the nose that helps to detects smell. The study team hopes to identify the tiny structures in that area and see how they might be different in people who have smell loss compared to those who do not. Participation in the study includes completing a smell test (Sniffin' Sticks Extended test), a cognitive screening test, and two questionnaires.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not 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

Aim 1: Evaluate the feasibility of in vivo CLE imaging of the olfactory cleft and nasal turbinate and determine whether CLE features correlate with validated psychophysical olfactory testing and patient-reported quality-of-life measures.

The study team will obtain preoperative Sniffin' Sticks threshold-discrimination-identification (TDI) scores and questionnaires in 36 surgical patients recruited from NH and VT, followed by intraoperative CLE imaging after intravenous fluorescein. CLE images will be assessed for epithelial features such as neuronal loss, epithelial thinning, basement membrane irregularity, and inflammatory changes.

Aim 2: Compare in vivo CLE imaging features with histopathologic findings from superior turbinate tissue, when available, to identify candidate in vivo imaging biomarkers. When routine surgery includes removal of superior turbinate tissue, CLE images will be paired with histopathology to assess concordance in features such as neuronal density, sustentacular cell integrity, and inflammation.

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.
Interventional

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.
36

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Early Phase 1

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 Contact Backup

Study Locations

  • United States
    • New Hampshire
      • Lebanon, New Hampshire, United States, 03755
        • Dartmouth-Hitchcock Medical Center

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Study Population

Adults undergoing endoscopic sinus or endonasal skull base surgery while under general anesthesia where the nasal turbinate is accessible at Dartmouth Hitchcock Medical Center.

Description

Inclusion Criteria:

  • Adults aged ≥18 years
  • Undergoing endoscopic sinus or endonasal skull base surgery while under - general anesthesia where the nasal turbinate is accessible
  • Able to complete study questionnaires and psychophysical smell testing
  • Able to provide informed consent.

Exclusion Criteria:

  • Known allergy or hypersensitivity to fluorescein
  • Pregnancy
  • Medical instability precluding participation
  • Severe anatomic obstruction preventing safe access to the olfactory cleft and nasal turbinate
  • Any other safety concern identified by the investigator

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

  • Primary Purpose: Diagnostic
  • Allocation: Non-Randomized
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
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.
Other: Target Group (Patients with Olfactory Complaints)
Patients who have olfactory complaints and are undergoing endoscopic sinus or endonasal skull base surgery while under general anesthesia where the nasal turbinate is accessible, per their standard of care.
Device: CONVIVO system
Approximately 2-5 minutes following administration of FNa in situ imaging will be performed by the participating surgeon ensuring proper technique. Prior to entering the surgical field, the probe will be covered in a disposable sterile sheath that is manufactured with quality assurance for this purpose. The probe will gently be held against the tissue interface while imaging occurs. Following image acquisition, a pathologist present in the operating room, will review and capture each image.
Drug: Fluorescein injection, USP 10%
Sodium fluorescein will be administered intravenously or topically (applied directly to nasal mucosa) at doses of 5-10 mg/kg (not exceeding 20 mg/kg cumulative). Administration will be performed by the anesthesia team in the operating room.
Other Names:
  • AK-FLUOR
  • FNa
Other: Control Group
Controls will consist of surgical patients without subjective olfactory complaints and with expected normal psychophysical testing. Patients who are already undergoing endoscopic sinus or endonasal skull base surgery while under general anesthesia where the nasal turbinate is accessible, per their standard of care.
Device: CONVIVO system
Approximately 2-5 minutes following administration of FNa in situ imaging will be performed by the participating surgeon ensuring proper technique. Prior to entering the surgical field, the probe will be covered in a disposable sterile sheath that is manufactured with quality assurance for this purpose. The probe will gently be held against the tissue interface while imaging occurs. Following image acquisition, a pathologist present in the operating room, will review and capture each image.
Drug: Fluorescein injection, USP 10%
Sodium fluorescein will be administered intravenously or topically (applied directly to nasal mucosa) at doses of 5-10 mg/kg (not exceeding 20 mg/kg cumulative). Administration will be performed by the anesthesia team in the operating room.
Other Names:
  • AK-FLUOR
  • FNa

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
Evaluate the feasibility of in vivo CLE imaging of the olfactory cleft and nasal turbinate and determine whether CLE features correlate with validated psychophysical olfactory testing and patient-reported quality-of-life measures.
Time Frame: On day of Surgery, Day 0
(1) High feasibility (≥85% interpretable images); (2) identifiable CLE signatures associated with OD severity; (3) significant correlations between CLE features, TDI scores, and symptom burden.
On day of Surgery, Day 0

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
Compare in vivo CLE imaging features with histopathologic findings from superior turbinate tissue, when available, to identify candidate in vivo imaging biomarkers.
Time Frame: On day of Surgery, Day 0

When routine surgery includes removal of superior turbinate tissue, CLE images will be paired with histopathology to assess concordance in features such as neuronal density, sustentacular cell integrity, and inflammation.

Expected Outcomes: Identification of CLE features corresponding to gold-standard histopathology, generating preliminary in vivo imaging biomarkers.
On day of Surgery, Day 0

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.
Dartmouth-Hitchcock Medical Center

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Center for Advancing Translational Sciences (NCATS)

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.
April 28, 2026

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.
April 30, 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.
July 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).
April 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.
April 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.
April 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 2, 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.
August 31, 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.
August 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.
  • STUDY02003356
  • UM1TR004772 (U.S. NIH Grant/Contract)

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

Yes

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

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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