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NCT Number: NCT07347535

Non-invasive MSOT Examination of Muscle Oxygenation in Athletes and PAD Patients

The aim of the study is to present the quantitative differences in oxygenated hemoglobin in different cohorts.

This clinical study evaluates whether there is a correlation between measurements using multispectral optoacoustic tomography and the results of spiroergometry in the context of performance diagnostics.

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Key information

Conditions

PAD - Peripheral Arterial Disease

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Observational

About this study

This study aims to investigate the muscle metabolism of athletes (endurance and strength athletes), PAD patients, and healthy control subjects using non-invasive multispectral optoacoustic tomography as part of interval treadmill spiroergometry. The aim is to take a closer look at changes in oxygen supply and muscle metabolism in the various patient groups during the recovery phase. To this end, the individual groups will perform a performance diagnosis on a treadmill spiroergometer, adapted to their respective estimated physical performance (in the case of PAD patients, taking into account the possibilities given by the disease), which will be carried out in the form of a step test. In addition, MSOT measurements will be taken between the individual steps.

The aim of this study is to use MSOT to visualize and compare the muscle perfusion-in particular the proportion of oxygenated and deoxygenated hemoglobin (Hb)-of the various cohorts, as well as to compare it with the diagnostics and methods commonly used to date and identify any advantages. In the future, this could contribute to a better understanding of muscle perfusion, especially in connection with diseases such as PAD or other muscle lesions in sports medicine.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age ≥ 18 years (adults capable of giving consent)
  • Capacity to consent. The subjects are able to understand the information provided and give their written consent.
  • Belonging to one of the following cohorts:
  • Endurance athletes: at least 3× per week ≥ 60 minutes of intensive endurance training (e.g., running, cycling, swimming)
  • Strength athletes: at least 3× per week ≥ 60 minutes of intensive strength training without additional endurance training
  • Healthy control subjects: less than 2× per week < 30 minutes of physical activity, no known vascular diseases
  • PAD patients: diagnosed peripheral arterial occlusive disease in Fontaine stage I or IIa Women of childbearing age with or without contraception may participate, as there are no risks of harm to the fetus.
  • Consent to pseudonymized data collection and storage in accordance with the GDPR.

Exclusion criteria

  • Age over 75 years
  • Minors (Age < 18)
  • safety concerns on the part of the study physician, e.g., in the case of of: physical, mental or psychiatric illnesses, acute or chronic conditions that could jeopardise safety or data quality
  • Taking medications that could affect physical performance or physiological measurements (e.g., heart rate, oxygen uptake).
  • Pregnancy with known risks or complications (participation is possible in principle, but subject to individual medical review).
  • Refusal to participate or lack of informed consent.

Treatment and study plan

MSOT - Multispectral optoacustic tomography

Diagnostic Test

MSOT is an advanced imaging technology that combines laser-induced ultrasound and light absorption to visualize biological tissues. By detecting ultrasound waves generated from tissue absorption of multispectral light, MSOT provides high-resolution, real-time images with functional and molecular information. One of its use is in biomedical research and clinical applications to study blood oxygenation and tissue composition, making it valuable for areas such as vascular research. In this study, we aim to utilize MSOT to differentiate between venous, arteriovenous and lymphatic malformations.

CPET

Diagnostic Test

Spiroergometry (also called cardiopulmonary exercise testing, CPET) is a diagnostic test that measures how the heart, lungs, and muscles work together during physical activity. While a person performs exercise treadmill the test records breathing gases (oxygen uptake and carbon dioxide output), ventilation, heart rate, and workload.

It provides valuable information about aerobic capacity, endurance, and limitations caused by cardiovascular, pulmonary, or metabolic conditions, making it useful in sports medicine, rehabilitation, and clinical diagnostics.

Primary outcomes

  1. Hemoglobin associated parameters measured via Multispectral optoacoustic Tomography

    Time frame: through study completion, an average of 1 year

    using MSOT

  2. Peak oxygen uptake (VO₂peak): VO₂peak (mL·kg-¹·min-¹)

    Time frame: through study completion, an average of 1 year

    Peak oxygen uptake measured during cardiopulmonary exercise testing (CPET), defined as the highest oxygen uptake achieved during maximal exercise.

  3. Respiratory exchange ratio (RER): RER (VCO₂/VO₂, unitless)

    Time frame: Through study completion, average of 1 year

    Respiratory exchange ratio measured during cardiopulmonary exercise testing (CPET) and calculated as the ratio of carbon dioxide production to oxygen consumption (VCO₂/VO₂).

  4. Minute ventilation: Ventilation (L·min-¹)

    Time frame: Through study completion, average of 1 year

    Minute ventilation measured during cardiopulmonary exercise testing (CPET).

  5. Carbon dioxide production (VCO₂): VCO₂ (mL·min-¹)

    Time frame: Through study completion, average of 1 year

    Carbon dioxide production measured during cardiopulmonary exercise testing (CPET).

  6. Heart rate response to exercise: Heart rate (bpm)

    Time frame: Through study completion, average of 1 year

    Heart rate measured at peak exercise during cardiopulmonary exercise testing (CPET).

  7. Absolute oxygen consumption: VO₂ (mL·min-¹)

    Time frame: Through study completion, average of 1 year

    Oxygen consumption measured during cardiopulmonary exercise testing (CPET).

  8. Anaerobic threshold: HR or workload at AT unit: bpm or km/h

    Time frame: Through study completion, average of 1 year

    Heart rate and workload at anaerobic threshold determined during cardiopulmonary exercise testing (CPET).

  9. Breathing reserve; Percentage (%)

    Time frame: Through study completion (an average of 1 year)

    using CPET Breathing reserve measured during cardiopulmonary exercise testing (CPET) and calculated as the percentage difference between maximal voluntary ventilation and peak exercise ventilation.

  10. Ventilatory equivalent for oxygen (VE/VO₂): Unitless

    Time frame: Through study completion (an average of 1 year)

    Ventilatory equivalent for oxygen measured during cardiopulmonary exercise testing (CPET) and defined as the ratio of minute ventilation to oxygen consumption.

  11. Ventilatory equivalent for carbon dioxide (VE/VCO₂): Unitless

    Time frame: Through study completion (an average of 1 year)

    Ventilatory equivalent for carbon dioxide measured during cardiopulmonary exercise testing (CPET) and defined as the ratio of minute ventilation to carbon dioxide production.

Sponsors and collaborators

Lead sponsor

University Hospital Erlangen

Other

Collaborators

  • PD Dr. med. Ferdinand Knieling, Department of pediatrics, University of Erlangen-Nürnberg

Registry information

Official study title

Non-invasive Assessment of Skeletal Muscle Oxygenation in Athletes and Patients With Peripheral Arterial Disease Using Multispectral Optoacoustic Tomography During Standardized Physical Exercise

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Jan 16, 2026
Registry last updated
Jan 16, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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