MRI of the central nervous system in MS patients with and without pain.
BACKGROUND
Central pain (CP) is a common symptom in MS. Multiple theories are present about the mechanism of CP. Previous studies suggested that lesion of the spinothalamic tract is a necessary condition for development of CP. No previous study has in detail evaluated the association between the specific site of demyelinations and the presence of CP in MS.


OBJECTIVE
The study aimed to evaluate the location of plaques in MS patients with CP including a group of MS patients without pain as a reference group.


METHODS
All patients underwent a bedside sensory examination and MRI of the brain and spinal cord. MR imaging was acquired on an 1.5 Tesla MR equipment. A trained neuroradiologist, blinded to pain status, evaluated the MRI.


RESULTS
Thirteen MS patients with CP and 10 MS patients without pain were included. Allodynia and/or dysesthesia were more frequent in pain patients (11/13 vs. 1/10, P<0.01). No difference was found in the number of patients with plaques in spinothalamic tract, dorsal column-medial lemniscus, dorsolateral funiculus, grey substance, thalamus or capsula interna. A non-significantly lower number of pain patients had lesions in thalamo-cortical pathways (8/13 vs. 10/10, P=0.027).


CONCLUSIONS
No association between CP and site of demyelinations was found, although a trend toward a higher prevalence of intact thalamo-cortical pathways was seen in pain patients. CP was associated with allodynia, suggesting central hyperexcitability.
Svendsen
Kristina Bacher
KB
Danish Pain Research Center, University Hospital of Aarhus, Aarhus, Denmark. kristina@akhphd.au.dk
Sørensen
Leif
L
Jensen
Troels Stahelin
TS
Hansen
Hans Jacob
HJ
Bach
Flemming Winther
FW
D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology; D002490:Central Nervous System / Q000473:pathology*; D003430:Cross-Sectional Studies; D003627:Data Interpretation, Statistical; D003711:Demyelinating Diseases / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications* / Q000473:pathology*; D010146:Pain / Q000209:etiology* / Q000473:pathology*; D010147:Pain Measurement; D012678:Sensation Disorders / Q000209:etiology / Q000473:pathology; D013116:Spinal Cord / Q000473:pathology; D013133:Spinothalamic Tracts / Q000473:pathology; D013788:Thalamus / Q000473:pathology