RESUMEN
OBJECTIVE: This study compared cortical and sub-cortical volumes between patients with complicated (i.e. presence of intracranial abnormality on the day-of-injury CT) and uncomplicated (i.e. absence of intracranial abnormality) mild traumatic brain injury (MTBI) 4 weeks post-injury. The study hypothesized regionally decreased brain volumes and reduced cortical thickness in patients with complicated MTBIs compared with uncomplicated MTBI. METHODS: This study was part of a larger 2 years cohort study on MTBI. Baseline clinical and magnetic resonance imaging (MRI) data were compared for those with complicated and uncomplicated MTBI. It identified 168 patients with MTBI (90 uncomplicated and 78 complicated), aged 16-65 years. 3T MRI-system (Signa HDxt, GE Medical Systems, Milwaukee, WI) and cortical reconstruction and volumetric segmentation by FreeSurfer software have been used. RESULTS: No significant differences between uncomplicated and complicated MTBIs were found in neuroanatomic volumes and cortical thickness after controlling for age, gender and education. The complicated MTBI group showed larger ventricles compared with the uncomplicated group, but this effect diluted when adjusting for potential confounders. CONCLUSION: The study findings suggest that the classification of complicated and uncomplicated MTBI may be too broad to differentiate volumetric and morphometric effects of injury in the early post-injury phase.
Asunto(s)
Conmoción Encefálica/diagnóstico por imagen , Encéfalo/diagnóstico por imagen , Imagen por Resonancia Magnética , Adolescente , Adulto , Anciano , Estudios de Cohortes , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Análisis de Regresión , Tomógrafos Computarizados por Rayos X , Adulto JovenRESUMEN
The sharpness expressed as the full-width at half-maximum of the line spread function (LSF) was derived for different CT scanners and reconstruction kernels. The LSFs were calculated from images of a 0.28 mm tungsten bead and successfully fitted to cumulative Gaussians by means of probit plots. The corresponding image noise was measured in a homogeneous material. The investigation showed that the noise increases strongly for small improvements in sharpness. The method was reproducible and insensitive to small positional shifts of the phantom.
