Magnetic Resonance Spectroscopy in Autonomic Failure

Study Overview
=================
Brief Summary
-----------------
This research study will be conducted in patients with primary autonomic failure, a disabling condition that is associated with low blood pressure upon standing. These patients are also not able to control for changes in their blood pressure due to a loss of cardiovascular reflexes that are mediated within the brain. The purpose of this study is to determine whether magnetic resonance spectroscopy (MRS), a non-invasive imaging technique, can measure levels of chemicals (neurotransmitters) in the dorsal medulla, a brain area important for control of cardiovascular function, in autonomic failure patients. Importantly, this study will determine whether there are differences in brain chemicals between patients with peripheral versus central origins of their autonomic failure. The hypothesis is that the neurotransmitter profile in the medulla will be intact in patients with peripheral autonomic failure compared to those with central impairment. Overall, this study will provide insight into understanding the mechanisms involved in autonomic failure and will determine whether a single session of MRS imaging can improve the ability to make an accurate diagnosis in these patients. This would lessen the need for more extensive and invasive clinical testing.

Official Title
-----------------
Proton Magnetic Resonance Spectroscopy in Primary Autonomic Failure

Conditions
-----------------
Pure Autonomic Failure, Multiple System Atrophy

Intervention / Treatment
-----------------
* Procedure: Magnetic Resonance Spectroscopy Imaging


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients with primary autonomic failure who are already participating in the approved Vanderbilt study Evaluation and Treatment of Autonomic Failure Males and females of all races between 18 and 80 years of age Able and willing to provide informed consent Exclusion Criteria: Pregnant women Patients with diagnosed Parkinson's Disease or secondary forms of autonomic failure Patients with severe claustrophobia Patients taking medications known to affect brain neurotransmitter levels [e.g., anti-depressants, barbiturates, benzodiazepines, gabapentin, namenda, sinemet] Patients with implanted medical devices [e.g., pacemakers, metal clips, cochlear implants, orthopedic hardware], lead-based tattoos or pieces of metal close to or in an important organ High-risk patients [e.g., heart failure, symptomatic coronary artery disease, liver impairment, history of stroke or myocardial infarction] Inability to give or withdraw informed consent Other factors which in the investigator's opinion would prevent the subject from completing the protocol including significant abnormalities in clinical, mental, or laboratory testing

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Pure Autonomic Failure<br>Pure autonomic failure is a type of primary autonomic failure characterized by peripheral autonomic nervous system impairment. | Procedure: Magnetic Resonance Spectroscopy Imaging<br>* Proton magnetic resonance spectroscopy [1H-MRS] is an emerging imaging tool that allows for non-invasive assessment of brain neurochemistry in human subjects. This technique allows for in vivo quantification of the concentration of neurotransmitters and metabolites in discrete brain regions through detection of hydrogen nuclei in these molecules. Autonomic failure patients will undergo a single imaging session lasting 30 to 90 minutes (0.5-1.5 hours) in the Vanderbilt Human Imaging Institute.<br>* Other names: MRS;|
| Multiple System Atrophy<br>Multiple system atrophy is a type of primary autonomic failure characterized by central autonomic nervous system impairment. | Procedure: Magnetic Resonance Spectroscopy Imaging<br>* Proton magnetic resonance spectroscopy [1H-MRS] is an emerging imaging tool that allows for non-invasive assessment of brain neurochemistry in human subjects. This technique allows for in vivo quantification of the concentration of neurotransmitters and metabolites in discrete brain regions through detection of hydrogen nuclei in these molecules. Autonomic failure patients will undergo a single imaging session lasting 30 to 90 minutes (0.5-1.5 hours) in the Vanderbilt Human Imaging Institute.<br>* Other names: MRS;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| N-Acetylaspartate Levels | Differences in levels of N-acetylaspartate in the dorsal medulla of pure autonomic failure versus multiple system atrophy patients using single session imaging. | 0.5-1.5 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Myoinositol Levels | Differences in levels of myoinositol in the dorsal medulla pure autonomic failure versus multiple system atrophy patients. | 0.5-1.5 hours | 
| GABA Levels | Differences in levels of the neurotransmitter GABA in the dorsal medulla of pure autonomic failure versus multiple system atrophy patients. | 0.5-1.5 hours | 
| Creatinine Levels | Differences in levels of creatinine-containing compounds in the dorsal medulla of pure autonomic failure versus multiple system atrophy patients. | 0.5-1.5 Hours | 
| Choline Levels | Differences in levels of choline-containing compounds in the dorsal medulla of pure autonomic failure versus multiple system atrophy patients. | 0.5-1.5 Hours | 
| Glutamate Levels | Differences in levels of glutamate in the dorsal medulla of pure autonomic failure versus multiple system atrophy patients. | 0.5-1.5 Hours | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
autonomic failure, mangenetic resonance, neurochemistry, neurotransmitter, glutamate