[The clinical relevance of FDG-PET imaging in severe traumatic brain injuries]. / Relevancia clínica de la FDG-PET en los traumatismos craneoencefálicos graves.

AIM: To evaluate the usefulness of positron emission tomography (PET) as a predictor of long-term disability after a severe traumatic brain injury (TBI). PATIENTS AND METHODS: Fifty-six patients who had sustained a severe TBI were assessed with a broad battery of cognitive and functional scales at baseline and 6-months after inclusion in a multidisciplinary rehabilitation program. All patients underwent a FDG-PET at baseline. A physician blind to clinical data performed a semiquantitative analysis (normal vs altered) of functional neuroimaging (PET), including four cortical and three subcortical areas. The total number of lesions (cortical, subcortical and total) was correlated to the intensity of the TBI and to clinical data at admission and at follow-up. RESULTS: All patients showed changes in cerebral metabolism, being the thalamus the area most frequently affected. The degree of cerebral hypometabolism showed a significant correlation with TBI severity, functional disability, global outcome and cognitive impairment not only at baseline but also at follow-up. CONCLUSIONS: According to our results, FDG-PET may be a useful tool when studying brain dysfunction after severe TBI. FDG-PET findings correlate with the TBI severity, and with the level of patients' disability, as well as with the degree of memory and intelligence impairment. However, clinical variables related to the severity of the TBI, still are the best predictors of functional outcome after TBI.

Relevancia clínica de la FDG-PET en los traumatismos craneoencefálicos graves / The clinical relevance of FDG-PET imaging in severe traumatic brain injuries

Resumen. Objetivo. Demostrar la utilidad de la tomografía por emisión de positrones (PET) como predictor de la discapacidad a largo plazo tras un traumatismo craneoencefálico (TCE). Pacientes y métodos. Se evaluó neuropsicológica y funcionalmente a 56 pacientes que habían sufrido un TCE grave al inicio y aproximadamente seis meses después de su inclusión en un programa de rehabilitación multidisciplinar. A todos los pacientes se les realizó una tomografía por emisión de positrones con fluordeoxiglucosa al inicio del tratamiento. De forma ciega, se determinó la presencia o ausencia de alteraciones en cuatro áreas corticales y tres subcorticales, y se determinaron tres índices cualitativos de metabolismo cerebral (cortical, subcortical y total). Los índices de metabolismo se correlacionaron con las variables relacionadas con la gravedad del traumatismo, y con la situación cognitiva y funcional de los pacientes en el momento de realizar la PET y al finalizar el programa de rehabilitación. Resultados. Todos los pacientes mostraron alteraciones en el metabolismo cerebral, y el tálamo fue el área más frecuentemente afectada. La intensidad del hipometabolismo cerebral se correlacionó significativamente con la gravedad del TCE y con la alteración cognitiva y funcional tanto al inicio como al final del tratamiento. Conclusiones. Las técnicas de neuroimagen funcional presentan una excelente sensibilidad para detectar alteraciones tras un TCE, además de ofrecer una buena correlación anatomoclínica. No obstante, las variables relacionadas con la gravedad del TCE, siguen siendo las mejores predictoras de la discapacidad resultante tras un TCE (AU)

Summary. Aim. To evaluate the usefulness of positron emission tomography (PET) as a predictor of long-term disability after a severe traumatic brain injury (TBI). Patients and methods. Fifty-six patients who had sustained a severe TBI were assessed with a broad battery of cognitive and functional scales at baseline and 6-months after inclusion in a multidisciplinary rehabilitation program. All patients underwent a FDG-PET at baseline. A physician blind to clinical data performed a semiquantitative analysis (normal vs altered) of functional neuroimaging (PET), including four cortical and three subcortical areas. The total number of lesions (cortical, subcortical and total) was correlated to the intensity of the TBI and to clinical data at admission and at follow-up. Results. All patients showed changes in cerebral metabolism, being the thalamus the area most frequently affected. The degree of cerebral hypometabolism showed a significant correlation with TBI severity, functional disability, global outcome and cognitive impairment not only at baseline but also at follow-up. Conclusions. According to our results, FDG-PET may be a useful tool when studying brain dysfunction after severe TBI. FDG-PET findings correlate with the TBI severity, and with the level of patients’ disability, as well as with the degree of memory and intelligence impairment. However, clinical variables related to the severity of the TBI, still are the best predictors of functional outcome after TBI (AU)