Is the Volume of the Caudate Nuclei Associated With Area of Secondary Hyperalgesia? - Protocol for a 3-Tesla MRI Study of Healthy Volunteers.
BACKGROUND
Experience and development of pain may be influenced by a number of physiological, psychological, and psychosocial factors. In a previous study we found differences in neuronal activation to noxious stimulation, and microstructural neuroanatomical differences, when comparing healthy volunteers with differences in size of the area of secondary hyperalgesia following a standardized burn injury.


OBJECTIVE
We aim to investigate the degree of association between the volume of pain-relevant structures in the brain and the size of the area of secondary hyperalgesia following brief thermal sensitization.


METHODS
The study consists of one experimental day, in which whole-brain magnetic resonance imaging (MRI) scans will be conducted including T1-weighed three-dimensional anatomy scan, diffusion tensor imaging, and resting state functional MRI. Before the experimental day, all included participants will undergo experimental pain testing in a parallel study (Clinicaltrials.gov Identifier: NCT02527395). Results from this experimental pain testing, as well as the size of the area of secondary hyperalgesia from the included participants, will be extracted from this parallel study.


RESULTS
The association between the volume of pain-relevant structures in the brain and the area of secondary hyperalgesia will be investigated by linear regression of the estimated best linear unbiased predictors on the individual volumes of the pain relevant brain structures.


CONCLUSIONS
We plan to investigate the association between experimental pain testing parameters and the volume, connectivity, and resting state activity of pain-relevant structures in the brain. These results may improve our knowledge of the mechanisms responsible for the development of acute and chronic pain.


BACKGROUND
Danish Research Ethics Committee (identifier: H-15010473). Danish Data Protection Agency (identifier: RH-2015-149). Clinicaltrials.gov NCT02567318; http://clinicaltrials.gov/ct2/show/NCT02567318 (Archived by WebCite at http://www.webcitation.org/6i4OtP0Oi).
Department of Anaesthesiology, 4231, Centre of head and orthopaedics, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark. morten.sejer.hansen@regionh.dk.
Morten Sejer
http://orcid.org/0000-0002-1568-3831
MS
Hansen
Mohammad Sohail
http://orcid.org/0000-0002-3759-2674
MS
Asghar
Jørn
http://orcid.org/0000-0001-7778-1771
J
Wetterslev
Christian Bressen
http://orcid.org/0000-0003-0261-616X
CB
Pipper
Johan
http://orcid.org/0000-0003-1620-7527
J
Johan Mårtensson
Lino
http://orcid.org/0000-0002-5840-1160
L
Becerra
Anders
http://orcid.org/0000-0003-1325-9049
A
Christensen
Janus Damm
http://orcid.org/0000-0003-3066-3908
JD
Nybing
Inger
http://orcid.org/0000-0002-8110-8931
I
Havsteen
Mikael
http://orcid.org/0000-0002-8774-6563
M
Boesen
Jørgen Berg
http://orcid.org/0000-0002-5913-456X
JB
Dahl
Anaesthesiology; Central sensitization; Hyperalgesia; Magnetic resonance imaging; Pain; Physiology; Quantitative sensory testing