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

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

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.

Study Overview

• Status: Not yet recruiting
• Conditions: PAD - Peripheral Arterial Disease
• Intervention / Treatment: Diagnostic test: MSOT - Multispectral optoacustic tomography; Diagnostic test: CPET

Detailed Description

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.

• Study Type: Observational
• Enrollment (Estimated): 60

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

The study will include adult participants aged 18 to 75 years, representing different levels of physical activity and vascular health status. A total of approximately 60 participants will be recruited, divided into six cohorts of about ten individuals each.

Cohort Description:

• Young endurance athletes (≥ 3 times per week, ≥ 60 minutes per session) Examples: running, cycling, swimming
• Young strength athletes (≥ 3 times per week, ≥ 60 minutes) No additional endurance training
• Young healthy controls Less than 2 times per week and < 30 minutes of physical activity No known vascular or muscular diseases
• Patients with peripheral arterial disease (PAD) Diagnosed with PAD, Fontaine stage I, IIa or IIb
• Older inactive controls Age above 55 years, no regular physical activity, no pAVK
• Patients with PAD (Fontaine stage I, IIa or IIb, who participate in structured walking training

Description

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.

Study Plan

How is the study designed?

Number of groups / cohorts

6

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
PAD - peripheral artery disease; Patients with PAD	Diagnostic test: MSOT - Multispectral optoacustic tomography; 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.; Diagnostic test: CPET; 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.
Triathletes; very fit subjects, who do triathlon	Diagnostic test: MSOT - Multispectral optoacustic tomography; 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.; Diagnostic test: CPET; 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.
Strength athletes; Strength athletes and bodybuilders	Diagnostic test: MSOT - Multispectral optoacustic tomography; 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.; Diagnostic test: CPET; 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.
young, unathletic group; Young, healthy and unathletic subjects between 18 - 40 years	Diagnostic test: MSOT - Multispectral optoacustic tomography; 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.; Diagnostic test: CPET; 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.
older, unathletic group; older, unathletic and healthy subjects between 55 - 75 years	Diagnostic test: MSOT - Multispectral optoacustic tomography; 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.; Diagnostic test: CPET; 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.
training PAD Patients	Diagnostic test: MSOT - Multispectral optoacustic tomography; 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.; Diagnostic test: CPET; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hemoglobin associated parameters measured via Multispectral optoacoustic Tomography	using MSOT	through study completion, an average of 1 year
Peak oxygen uptake (VO₂peak): VO₂peak (mL·kg-¹·min-¹)	Peak oxygen uptake measured during cardiopulmonary exercise testing (CPET), defined as the highest oxygen uptake achieved during maximal exercise.	through study completion, an average of 1 year
Respiratory exchange ratio (RER): RER (VCO₂/VO₂, unitless)	Respiratory exchange ratio measured during cardiopulmonary exercise testing (CPET) and calculated as the ratio of carbon dioxide production to oxygen consumption (VCO₂/VO₂).	Through study completion, average of 1 year
Minute ventilation: Ventilation (L·min-¹)	Minute ventilation measured during cardiopulmonary exercise testing (CPET).	Through study completion, average of 1 year
Carbon dioxide production (VCO₂): VCO₂ (mL·min-¹)	Carbon dioxide production measured during cardiopulmonary exercise testing (CPET).	Through study completion, average of 1 year
Heart rate response to exercise: Heart rate (bpm)	Heart rate measured at peak exercise during cardiopulmonary exercise testing (CPET).	Through study completion, average of 1 year
Absolute oxygen consumption: VO₂ (mL·min-¹)	Oxygen consumption measured during cardiopulmonary exercise testing (CPET).	Through study completion, average of 1 year
Anaerobic threshold: HR or workload at AT unit: bpm or km/h	Heart rate and workload at anaerobic threshold determined during cardiopulmonary exercise testing (CPET).	Through study completion, average of 1 year
Breathing reserve; Percentage (%)	using CPET Breathing reserve measured during cardiopulmonary exercise testing (CPET) and calculated as the percentage difference between maximal voluntary ventilation and peak exercise ventilation.	Through study completion (an average of 1 year)
Ventilatory equivalent for oxygen (VE/VO₂): Unitless	Ventilatory equivalent for oxygen measured during cardiopulmonary exercise testing (CPET) and defined as the ratio of minute ventilation to oxygen consumption.	Through study completion (an average of 1 year)
Ventilatory equivalent for carbon dioxide (VE/VCO₂): Unitless	Ventilatory equivalent for carbon dioxide measured during cardiopulmonary exercise testing (CPET) and defined as the ratio of minute ventilation to carbon dioxide production.	Through study completion (an average of 1 year)

Collaborators and Investigators

• Sponsor: University Hospital Erlangen
• Collaborators: PD Dr. med. Ferdinand Knieling, Department of pediatrics, University of Erlangen-Nürnberg

Study record dates

Study Major Dates

• Study Start (Estimated): January 1, 2026
• Primary Completion (Estimated): March 1, 2026
• Study Completion (Estimated): August 1, 2026

Study Registration Dates

• First Submitted: December 11, 2025
• First Submitted That Met QC Criteria: January 14, 2026
• First Posted (Estimated): January 16, 2026

Study Record Updates

• Last Update Posted (Estimated): January 16, 2026
• Last Update Submitted That Met QC Criteria: January 14, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: PAD; MSOT; Spiroergometry
• Other Study ID Numbers: MSOT_SPO2RT

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No