Measurement of brain temperature with magnetic resonance spectroscopy in acute ischemic stroke.
OBJECTIVE
Pyrexia is associated with poor outcome after stroke, but the temperature changes in the brain after stroke are poorly understood. We used magnetic resonance spectroscopic imaging (water-to-N-acetylaspartate frequency shift) to measure cerebral temperature noninvasively in stroke patients.


METHODS
We performed magnetic resonance diffusion, perfusion (diffusion- and perfusion-weighted imaging), and magnetic resonance spectroscopic imaging, compared temperatures in tissues as defined by the diffusion-weighted imaging appearance (definitely abnormal, possibly abnormal and immediately adjacent normal-appearing brain, and normal brain), and tested associations with lesion and patient characteristics.


RESULTS
Among 40 patients, temperature was higher in possibly abnormal (37.63 degrees C) than in definitely abnormal tissue (37.30 degrees C; p < 0.001) or in normal-appearing brain (ipsilateral, 37.16 degrees C; contralateral, 37.22 degrees C; both p < 0.001). Ischemic lesion temperature increased before normal brain temperature. Higher temperatures occurred in lesions that were large, had diffusion/perfusion-weighted imaging mismatch, had reduced cerebral blood flow, and in clinically severe strokes. Only 1 of 25 patients with ischemic lesion temperature greater than 37.5 degrees C was pyrexial.


CONCLUSIONS
Temperature is elevated in acutely ischemic brain. More work is required to determine whether raised temperature results from ischemic metabolic reactions, impaired heat exchange from reduced cerebral blood flow, or early inflammatory cell activity (or a combination of these), but magnetic resonance spectroscopic imaging could be used in studies of temperature after brain injury and to monitor interventions.
Karaszewski
Bartosz
B
Department of Neurology of Adults, Medical University of Gdansk, Gdansk, Poland.
Wardlaw
Joanna M
JM
Marshall
Ian
I
Cvoro
Vera
V
Wartolowska
Karolina
K
Haga
Kristin
K
Armitage
Paul A
PA
Bastin
Mark E
ME
Dennis
Martin S
MS
D000368:Aged; D000369:Aged, 80 and over; D001831:Body Temperature / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D002545:Brain Ischemia / Q000150:complications; D002560:Cerebrovascular Circulation / Q000502:physiology; D003627:Data Interpretation, Statistical; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D020521:Stroke / Q000209:etiology / Q000503:physiopathology*