[Thalamic metabolism and neurological outcome after traumatic brain injury. A voxel-based morphometric FDG-PET study].
OBJECTIVE
to study the relationship between thalamic metabolism and neurological outcome in patients who had sustained a traumatic brain injury (TBI).


METHODS
nineteen patients who had sustained a severe TBI and ten control subjects were included in this study. Six of the 19 patients had a low level of consciousness (vegetative state or minimally conscious state), while thirteen showed normal consciousness. All patients underwent a PET with 18F-FDG, 459.4 +/- 470.9 days after the TBI. The FDG-PET images were normalized in intensity, with a metabolic template being created from data derived from all subjects. The thalamic trace was generated automatically with a mask of the region of interest in order to evaluate its metabolism. A comparison between the two groups was carried out by a two sample voxel-based T-test, under the General Linear Model (GLM) framework.


RESULTS
patients with low consciousness had lower thalamic metabolism (MNI-Talairach coordinates: 12, -24, 18; T = 4.1) than patients with adequate awareness (14, -28, 6; T = 5.5). Control subjects showed the greatest thalamic metabolism compared to both patients groups. These differences in metabolism were more pronounced in the internal regions of the thalamus.


CONCLUSIONS
the applied method may be a useful ancillary tool to assess neurological outcomes after a TBI, since it permits an objective quantitative assessment of metabolic function for groups of subjects. Our results confirm the vulnerability of the thalamus to suffering the effects of the acceleration-deceleration forces generated during a TBI. It is hypothesized that patients with low thalamic metabolism represent a subset of subjects highly vulnerable to neurological and functional disability after TBI.
Lull
N
N
ITACA Grupo de Informática Biomédica, Instituto ITACA, Universidad Politécnica de Valencia, Valencia, España Universidad CEU Cardenal Herrera, Valencia, España.
Noé
E
E
Lull
J J
JJ
García-Panach
J
J
García-Martí
G
G
Chirivella
J
J
Ferri
J
J
Sopena
R
R
de La Cueva
L
L
Robles
M
M
D000293:Adolescent; D000328:Adult; D001930:Brain Injuries / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D003128:Coma / Q000378:metabolism; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D008297:Male; D018458:Persistent Vegetative State / Q000378:metabolism; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000378:metabolism; D013788:Thalamus / Q000378:metabolism* / Q000473:pathology; D055815:Young Adult
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18