Influence of Fitzpatrick Skin Phototype and Body Mass Index on Non-invasive Optoacoustic Imaging
- Conditions
- Healthy
- Interventions
- Device: Multispectral Optoacoustic Tomography (MSOT)
- Registration Number
- NCT06541496
- Lead Sponsor
- University of Erlangen-Nürnberg Medical School
- Brief Summary
Multispectral Optoacoustic Tomography (MSOT) is a promising imaging technology that utilizes pulsed laser light. While melanin content in the skin has been reported to influence light-based measurements in pulse oximetry and near-infrared spectroscopy, its effects on MSOT are not well understood. This proposed study aims to investigate how different Fitzpatrick skin phenotypes (FSP) and body mass index (BMI) influence muscle perfusion and oxygenation during arterial occlusion and muscle exercise over time. Healthy volunteers with varying skin tones (as defined by FSP) and BMI will be recruited and subjected to leg arterial occlusion and toe raise exercises. They will then be scanned on different body areas (arms and legs) to assess changes in muscle perfusion and oxygenation using MSOT.
- Detailed Description
Melanin, a pigment found in the skin, has been reported to influence light-based measurements such as pulse oximetry or near-infrared spectroscopy (NIRS). Studies have shown measurements overestimation of darker skin tones or in ethnicities assumed to have darker skin tones compared to lighter skin tones. Even though optoacoustic imaging (OAI) has a different depth penetration than NIRS or pulse oximetry, the technology uses pulse laser light to assess tissue.
Multispectral Optoacoustic Tomography (MSOT) imaging is similar to conventional sonography: a transducer is placed on the skin, and instead of sound, energy is applied to the tissue by means of pulsed laser light. This leads to a constant change of minimal expansion and contraction of individual tissue components or molecules. The resulting sound waves can then be detected by the same device. Previous studies have already shown that the quantitative determination of hemoglobin can provide information on inflammatory activities or muscle hemodynamics. MSOT uses laser light between 660 and 1300nm to visualize and quantify different endogenous chromophores, such as hemoglobin, collagen, or melanin. Increase in melanin concentration (e.g. in melanomas or skin tags) has been previously assessed using the technology but never looked at signal at depth. Additionally, differences in body-mass-index (BMI) might influence light penetration, and therefore, the optoacoustic signal at depth. So far, no studies have looked at the influence of increased melanin concentration or subcutaneous fat on quantification of muscle perfusion and oxygenation.
In this first pilot study, the aim is to investigate the influence of different Fitzpatrick skin phenotypes (FSP) and BMI on muscle perfusion and oxygenation during arterial occlusion or muscle exercise and over time. This information is essential for further studies with a more diverse study population.
To gain insights into these differences, healthy volunteers with different skin tone (defined by FSP) and body-mass-index will be recruited and subjected to a leg arterial occlusion and to perform a toe raise exercise. They will then be scanned on different body areas (arm, legs) to assess changes in muscle perfusion and oxygenation by MSOT.
Recruitment & Eligibility
- Status
- RECRUITING
- Sex
- All
- Target Recruitment
- 130
- Signed informed consent
- Pregnancy
- diagnosed diabetes
- diagnosed renal insufficiency
- diagnosed Peripheral arterial disease
- diagnosed muscle associated disease
- tattoos in scan area
- missing consent form
Study & Design
- Study Type
- OBSERVATIONAL
- Study Design
- Not specified
- Arm && Interventions
Group Intervention Description Fitzpatrick 1 Multispectral Optoacoustic Tomography (MSOT) Healthy volunteers with skin type 1. Fitzpatrick 3 Multispectral Optoacoustic Tomography (MSOT) Healthy volunteers with skin type 3. Fitzpatrick 4 Multispectral Optoacoustic Tomography (MSOT) Healthy volunteers with skin type 4. Fitzpatrick 5 Multispectral Optoacoustic Tomography (MSOT) Healthy volunteers with skin type 5. BMI Group 2 Multispectral Optoacoustic Tomography (MSOT) Healthy volunteers with BMI \>18.5 but \<25. Fitzpatrick 2 Multispectral Optoacoustic Tomography (MSOT) Healthy volunteers with skin type 2. Fitzpatrick 6 Multispectral Optoacoustic Tomography (MSOT) Healthy volunteers with skin type 6. BMI Group 3 Multispectral Optoacoustic Tomography (MSOT) Healthy volunteers with BMI \>25. BMI Group 1 Multispectral Optoacoustic Tomography (MSOT) Healthy volunteers with BMI \<18.5.
- Primary Outcome Measures
Name Time Method Quantitative hemoglobin-associated signal (in arbitrary units) immediately before and after intervention (occlusion and exercise) Hemoglobin signal in the measured muscle regions in all different cohorts
- Secondary Outcome Measures
Name Time Method Heart rate (in bpm) immediately before and after intervention (occlusion and exercise) heart rate of the healthy volunteers
Dominant side baseline Participant questionnaire.
Sport frequency baseline Participant questionnaire.
Muscle oxygenation (in arbitrary units) immediately before and after intervention (occlusion and exercise) Oxygenated hemoglobin signal in the measured muscle regions in all different cohorts
Oxygen saturation (in %) immediately before and after intervention (occlusion and exercise) Proportion of oxygenated hemoglobin signal compared with total hemoglobin signal in the measured muscle regions in all different cohorts
Weight (in kg) baseline measured by body scale
Gender: male, female, other baseline Participant questionnaire.
Skin tone based on Fitzpatrick scale examiner-assessment (type 1-6, 1 being the palest, 6 being the darkest) baseline color card as reference
Skin tone based on Fitzpatrick scale self-assessment (type 1-6, 1 being the palest, 6 being the darkest) baseline color card as reference
Blood pressure (in mm Hg) immediately before and after intervention (occlusion and exercise) blood pressure of the healthy volunteers
Age in years baseline Participant questionnaire.
Skin tone based on Fitzpatrick questionnaire self-assessment (type 1-6, 1 being the palest, 6 being the darkest) baseline Participant questionnaire.
Quantitative collagen, lipid, water and melanin signal (in arbitrary units) immediately before and after intervention (occlusion and exercise) Signal in the measured muscle regions and the skin (melanin) in all different cohorts
Information on last physical exercise and caffeine and alcohol consumption baseline Participant questionnaire.
Trial Locations
- Locations (1)
iThera Medical Headquarters
🇩🇪Munich, Bavaria, Germany