Is the Volume of the Caudate Nuclei Associated With Area of Secondary Hyperalgesia?

Study Overview
=================
Brief Summary
-----------------
The purpose of this prospective study is to investigate the degree of association between the volume of important pain-relevant structures in the brain and the size of the areas of secondary hyperalgesia.

Detailed Description
-----------------
The healthy study participants will be included from the cohort of a previous study (NCT02527395) where areas of secondary hyperalgesia, heat pain detection thresholds, pain during 1 min. thermal stimulation and test results from the Pain Catastrophizing Scale and the Hospital Anxiety and Depression Score will be retrieved. The study consists of 1 study day. The study day will be conducted at a maximum of 2 months and a minimum of 2 weeks after the completion of the previous study (NCT02527395).The results of the previous study (NCT02527395) will be blinded until all participants have completed the study day. All study participants will complete a MRI-scan of the brain. The MRI scans will be performed with a Siemens MAGNETOM Verio 3 tesla, with b17 software, and a 32-channel head coil. The MRI-scan sequence is as follows: 3D Localiser 3D T1 weighted iso AX Diffusion tensor imaging AX Epi resting state fMRI AX Gre field map AX Epi ASL AX T2-weighted blade AX T2-weighted flair AX T2-weighted* Gre Total MRI-scan time is estimated to approximately 40 minutes.

Official Title
-----------------
Is the Volume of the Caudate Nuclei Associated With Area of Secondary Hyperalgesia? - A Study of Healthy Volunteers

Conditions
-----------------
Pain, Secondary Hyperalgesia, Healthy Volunteers, Magnetic Resonance Imaging

Intervention / Treatment
-----------------
* Device: MRI-scan


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age >18 years and <35 years Speak and understand Danish Male sex Study participants who have understood and signed the informed consent No prescription medicine during the last 30 days. Have participated and completed the study with the identifier: NCT02527395. Exclusion Criteria: Study participants that cannot cooperate to the test. Study participants who have a weekly intake of >21 units of alcohol, or a have consumed >3 units of alcohol within 24 hours before experimental day. Study participants with a substance abuse, assessed by the investigator. Study participants, who have consumed analgesics less than 3 days before experimental day. Study participants, who have consumed antihistamines less than 48 hours before experimental day. Study participants, who have consumed antidepressant medication during the last 30 days before experimental day. Study participants with chronic pain. Study participants with neurological illnesses. Study participants with psychiatric diagnoses. Study participants with a Body Mass Index of >30 kg/m2 or <18 kg/m2 Study participants with Contraindications to MRI Study participants that decline information regarding potential pathological findings in relation to the MRI. Study participants that have any kind of trauma resulting in pain and administration of analgesics in the period between experimental pain testing and MRI-scan. Study participant that experience a head trauma in the period between the experimental pain testing and the MRI-scan.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
-----------------
Male

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

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

Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: MRI-scan<br>All study participants will complete a MRI-scan of the brain | Device: MRI-scan<br>* Magnetic resonance imaging scan of the brain<br>|

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Volume of the caudate nuclei, evaluated by mm3, and size of the area of secondary hyperalgesia following brief thermal sensitization, evaluated by cm2. | To investigate how close the volume of Caudate nucleus of the right and left hemisphere is associated with the size of the area of secondary hyperalgesia induced by Brief Thermal Sensitization. | 40 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Volume of cortical and subcortical areas, evaluated by mm3, and size of the area of secondary hyperalgesia following brief thermal sensitization, evaluated by cm2. | To investigate the association between cortical and subcortical brain areas relevant for pain processing and the area of secondary hyperalgesia (Primary somatosensory cortex, anterior and mid Cingulate cortex, Basal ganglia (Putamen, Accumbens nucleus, and Globus pallidus), Insula, and the Cerebellum. | 40 minutes | 
| White matter microstructure, evaluated by tract based spatial statistics, and size of the area area of secondary hyperalgesia, evaluated by cm2 | By Diffusion Tensor Imaging to investigate the association between area of secondary hyperalgesia and white matter microstructure using tract based spatial statistics (TBSS). | 40 minutes | 
| White matter microstructure, evaluated by tract based spatial statistics, and size of the area area of secondary hyperalgesia, evaluated by cm2 | By Diffusion Tensor Imaging to conduct white-matter tractography to determine the connections between cortical and subcortical brain areas relevant for pain processing (Primary somatosensory cortex, anterior and mid Cingulate cortex, Basal ganglia (Putamen, Accumbens nucleus, and Globus pallidus), Insula, and the Cerebellum) | 40 minutes | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Pain, Secondary hyperalgesia, Healthy volunteers, Magnetic Resonance Imaging