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This randomized crossover study aims to validate measurements of renal perfusion in healthy males with PET/CT, using 15-oxygen labeled water as tracer, against the validated multiparametric MRI technique.
The study will determine:
Measuring tissue perfusion with PET/CT using 15-oxygen labeled water is routinely used as a non-invasive tool to examine cerebral and myocardial perfusion. With a 100% tissue extraction, 15-oxygen labeled water is gold standard.
The aim of the present study is to validate renal perfusion measurements with PET/CT using 15-oxygen labeled water as tracer against the validated multiparametric MRI technique.
Once validated the imaging technique will be beneficial in examining vascular damage in the kidneys caused by different renal diseases.
This is a randomized, crossover study where each participant will participate in 1 study day.
Ten healthy male participants in the age group 20-60 years are screened and randomized, and expected to complete the present study. Informed consent is obtained before the screening meeting.
All participants consume a controlled diet with fixed salt intake corresponding to a daily intake of 50-70 mmol + 2 mmol/kg sodium for 4 days before the experiment. On the fourth day, 24-hour urine collection will be performed. Throughout the 4 day period, water intake will be ad libitum and physical activity will not be allowed.
Each participant will undergo both PET/CT and MRI separated by around 1.5 hour.
Total renal blood flow and regional renal perfusion are measured repeatedly altogether 5 times with both PET/CT and MRI. Renal oxygenation and oxygen extraction are measured repeatedly 5 times as well, using MRI. The 5 measurements consist of 2 at baseline (rest), 2 during isometric exercise (handgrip) and 1 during recovery (rest).
Isometric muscle exercise is conducted by squeezing a handgrip coupled to a dynamometer. This increases sympathetic nervous activity, leading to preglomerular vasoconstriction.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Group randomized to begin with MRI | Other | Group is randomized to begin with MRI and have PET/CT performed later on the same day |
|
| Group randomized to begin with PET/CT | Other | Group is randomized to begin with PET/CT and have MRI performed later on the same day |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| MRI | Procedure | MRI will be performed |
|
| Measure | Description | Time Frame |
|---|---|---|
| Coefficient of variation on total blood flow and regional renal perfusion measurements at rest and during isometric muscle exercise, measured by PET/CT with 15-Oxygen labeled water and MRI | No metric unit | Each participant's study day during the span of the study (approximately 5 months) |
| Total blood flow at rest and during isometric muscle exercise measured by PET/CT with 15-Oxygen labeled water and MRI | Volume of blood pr unit time, ml/min | Each participant's study day during the span of the study (approximately 5 months) |
| Regional renal perfusion at rest and during isometric muscle exercise measured by PET/CT with 15-Oxygen labeled water and MRI | Volume of blood pr unit time pr unit tissue mass, ml/min/g | Each participant's study day during the span of the study (approximately 5 months) |
| Regional renal oxygenation at rest and during isometric muscle exercise using MRI | Percentage, fraction | Each participant's study day during the span of the study (approximately 5 months) |
| Regional renal extraction of oxygen at rest and during isometric muscle exercise using MRI | Percentage, fraction | Each participant's study day during the span of the study (approximately 5 months) |
| Coefficient of variation on regional renal oxygenation and extraction of oxygen measurements at rest and isometric muscle exercise using MRI | No metric unit | Each participant's study day during the span of the study (approximately 5 months) |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Peter Sørensen, MD | Contact | +4530516279 | peter.soerensen@regionh.dk | |
| Ali Asmar, MD, PhD | Contact | ali.asmar@regionh.dk |
| Name | Affiliation | Role |
|---|---|---|
| Ali Asmar, MD, PhD | Bispebjerg Hospital, Department of Clinical Physiology and Nuclear Medicine | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Bispebjerg Hospital, Department of Clinical Physiology & Nuclear Medicine | Recruiting | Copenhagen | Capital Region | 2400 | Denmark |
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Each participant will undergo intervention, which is PET/CT, and control, which is MRI. Each participant will have both intervention and control performed the same day in randomized order.
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| PET/CT | Procedure | PET/CT will be performed |
|