Contrast-enhanced Multispectral Optoacoustic Tomography for Functional Assessment of the Gastrointestinal Transit

Study Overview
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Brief Summary
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This clinical trial aims to characterize a novel method of imaging the gastrointestinal tract in healthy subjects. The method is using laser-light and soundwaves and it is performed in a similar manner as conventional ultrasound. It is radiation-free and non-invasive. Participants will ingest food mixed with the clinically-registered dye Indocyanine green. Researchers will measure the signal of the dye over different segments of the gastrointestinal tract, visualizing gastrointestinal transit.

Detailed Description
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This clinical trial aims to assess gastrointestinal transit by using contrast-enhanced multispectral optoacoustic tomography (MSOT). MSOT is able to visualize not only endogenous chromophores like hemoglobin but also exogenous chromophores such as Indocyanine green (ICG). Healthy subjects will ingest three different standardized meals, all of which are mixed with ICG. By measuring the signal intensity of ICG during gastrointestinal transit, gut motility can be assessed non-invasive and radiation free. The goal is to compare transit times for different standardized meals, which are liquid, mushy, and solid.

Official Title
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Contrast-enhanced Multispectral Optoacoustic Tomography for Functional Assessment of the Gastrointestinal Transit

Conditions
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Gastrointestinal Motility

Intervention / Treatment
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* Diagnostic Test: Contrast-enhanced multispectral optoacoustic tomography


Participation Criteria
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Eligibility Criteria
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Inclusion criteria Age over 18 years Written informed consent Exclusion Criteria: General: Pregnancy Breastfeeding mothers Tattoo in the area of the examination Subcutaneous fat tissue over 3 cm Chronic or acute diseases of the gastrointestinal tract or symptoms suggesting such a disease Acute diseases requiring treatment Lack of written consent ICG related: Known hypersensitivity to ICG, sodium iodide or iodine. Hyperthyroidism, focal or diffuse thyroid autonomy. Timely close treatment to check thyroid function with ingestion of radioactive iodine (within two weeks before or after the study) Impaired renal function Taking the following medications: Beta blockers, anticonvulsants, cyclopropane, bisulfite compounds, haloperidol, heroin, meperidine, metamizole, methadone, morphine, nitrofurantoin, opium alkaloids, phenobarbital, phenylbutazone, probenecid, rifamycin, any injection containing sodium bisulfite

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Subjects will ingest three different standardized meals called breakfast 1, breakfast 2, and breakfast 3. They will ingest one meal per day, there is a minimum of 48 hours between measurement days. Every subject will ingest every meal.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Breakfast 1<br>Breakfast 1 is composed of 500 ml of water, mixed with 50 mg of ICG | Diagnostic Test: Contrast-enhanced multispectral optoacoustic tomography<br>* Ingestion of ICG-labeled food and 10 measurements with MSOT, 1 before ingestion of food, 8 afterwards, each after 60 minutes, 1 measurement 24 hours after ingestion<br>|
| Experimental: Breakfast 2<br>Breakfast 2 is composed of 200ml of yoghurt, mixed with 50 mg of ICG | Diagnostic Test: Contrast-enhanced multispectral optoacoustic tomography<br>* Ingestion of ICG-labeled food and 10 measurements with MSOT, 1 before ingestion of food, 8 afterwards, each after 60 minutes, 1 measurement 24 hours after ingestion<br>|
| Experimental: Breakfast 3<br>Breakfast 3 is composed of two slices white toast, two fried eggs and 30 g of jam, mixed with 50 mg of ICG | Diagnostic Test: Contrast-enhanced multispectral optoacoustic tomography<br>* Ingestion of ICG-labeled food and 10 measurements with MSOT, 1 before ingestion of food, 8 afterwards, each after 60 minutes, 1 measurement 24 hours after ingestion<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Transit-times of different segments of the gastrointestinal tract | Transit-times of the gastrointestinal passage | 2 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Signal-intensity of ICG | Measured with MSOT in arbitrary units | 2 days |