Cerebral Vascular Reserve in Small Vessel Disease and Alzheimers Disease

Study Overview
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Brief Summary
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Alzheimers disease and cerebral small vessel disease have a considerably overlap in patients and have common risk factors. The diseases are difficult to separate in individual patients and we hypothesize that a reduced cerebral vascular reserve may be a measurement of small vessel disease independent of Alzheimers disease. Patients with presumed Alzheimers disease (n=20), cerebral small vessel disease (n=20) and healthy age-matched subjects (n=15) are examined with quantitative [15O]H2O positron emission tomography (PET) for measurements of brain perfusion before and after diamox infusion that dilates cerebral vessels. Additional [15O]H2O PET scans of the heart allows for a non-invasive input function so the cerebral vascular reserve can be measured quantitatively.

Detailed Description
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Alzheimers disease and cerebral small vessel disease are increasingly common in the elderly population and constitute around 90% of new dementia cases in Denmark. The diseases have a considerably overlap in patients and have common risk factors. The cause of dementia can be difficult to separate in individual patients but a reduced cerebral vascular reserve may be a measurement of small vessel disease independent of Alzheimers disease. We hypothesized that patient with small vessel disease have reduced increase in brain perfusion after medical brain vessel dilatation. While Alzheimer patients may have reduced perfusion in rest but normal increase after medical brain vessel dilatation as compared to healthy subjects. Patients with presumed Alzheimers disease (n=20), cerebral small vessel disease (n=20) and healthy age-matched subjects (n=15) are examined with quantitative [15O]H2O PET for measurements of brain perfusion before and after diamox infusion that dilates cerebral vessels. Additional [15O]H2O PET scans of the heart allows for a non-invasive input function so the cerebral vascular reserve can be measured quantitatively.

Official Title
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Cerebral Vascular Reserve in Small Vessel Disease and Alzheimers Disease

Conditions
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Alzheimer Disease, Dementia, Vascular

Intervention / Treatment
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* Diagnostic Test: Cerebral [15O]H2O PET before and after diamox infusion


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: presumed Alzheimer's Disease (group 1) diagnosed with small vessel disease of the brain by MRI and presumed cognitive dysfunction (group 2) Exclusion Criteria: major claustrophobia major psychiatric diseases other major somatic diseases allergy to diamox

Ages Eligible for Study
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Minimum Age: 60 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Alzheimer Disease<br>patients with presumed Alzheimer disease and no known vascular, psychiatric or other major diseases age > 60 years | Diagnostic Test: Cerebral [15O]H2O PET before and after diamox infusion<br>* Cerebral [15O]H2O PET before and after diamox infusion<br>|
| Small vessel disease<br>patients diagnosed with small vessel disease of the brain by MRI and presumed cognitive dysfunction and no other known psychiatric or other major diseases. age > 60 years | Diagnostic Test: Cerebral [15O]H2O PET before and after diamox infusion<br>* Cerebral [15O]H2O PET before and after diamox infusion<br>|
| Healthy subjects<br>Age-matched subjects with no known vascular, psychiatric or other major diseases. age > 60 years | Diagnostic Test: Cerebral [15O]H2O PET before and after diamox infusion<br>* Cerebral [15O]H2O PET before and after diamox infusion<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vascular reserve perfusion | Brain perfusion after diamox infusion (mL / min / 100 g tissue) | 20 min after diamox infusion | 
| Vascular reserve change | Change in Brain perfusion after diamox infusion (mL / min / 100 g tissue and %) compared to before diamox infusion | 20 min after diamox infusion | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Positron-Emission Tomography, Perfusion