RESUMEN
Clinical outcome after traumatic diffuse axonal injury (DAI) is difficult to predict. In this study, three magnetic resonance imaging (MRI) sequences were used to quantify the anatomical distribution of lesions, to grade DAI according to the Adams grading system, and to evaluate the value of lesion localization in combination with clinical prognostic factors to improve outcome prediction. Thirty patients (mean 31.2 years ±14.3 standard deviation) with severe DAI (Glasgow Motor Score [GMS] <6) examined with MRI within 1 week post-injury were included. Diffusion-weighted (DW), T2*-weighted gradient echo and susceptibility-weighted (SWI) sequences were used. Extended Glasgow outcome score was assessed after 6 months. Number of DW lesions in the thalamus, basal ganglia, and internal capsule and number of SWI lesions in the mesencephalon correlated significantly with outcome in univariate analysis. Age, GMS at admission, GMS at discharge, and low proportion of good monitoring time with cerebral perfusion pressure <60 mm Hg correlated significantly with outcome in univariate analysis. Multivariate analysis revealed an independent relation with poor outcome for age (p = 0.005) and lesions in the mesencephalic region corresponding to substantia nigra and tegmentum on SWI (p = 0.008). We conclude that higher age and lesions in substantia nigra and mesencephalic tegmentum indicate poor long-term outcome in DAI. We propose an extended MRI classification system based on four stages (stage I-hemispheric lesions, stage II-corpus callosum lesions, stage III-brainstem lesions, and stage IV-substantia nigra or mesencephalic tegmentum lesions); all are subdivided by age (≥/<30 years).
Asunto(s)
Hemorragia Cerebral/diagnóstico por imagen , Lesión Axonal Difusa/diagnóstico por imagen , Imagen por Resonancia Magnética/tendencias , Sustancia Negra/diagnóstico por imagen , Tegmento Mesencefálico/diagnóstico por imagen , Adolescente , Adulto , Hemorragia Cerebral/clasificación , Hemorragia Cerebral/epidemiología , Lesión Axonal Difusa/clasificación , Lesión Axonal Difusa/epidemiología , Femenino , Escala de Coma de Glasgow/tendencias , Humanos , Imagen por Resonancia Magnética/clasificación , Masculino , Persona de Mediana Edad , Factores de Tiempo , Tomografía Computarizada por Rayos X/clasificación , Tomografía Computarizada por Rayos X/tendencias , Resultado del Tratamiento , Adulto JovenRESUMEN
The knowledge about the diffuse axonal injury (DAI) as a clinicopathological entity has matured in the last 30 years. It has been defined clinically (immediate and prolonged unconsciousness leading to death or severe disability) and pathologically (the triad of DAI specific changes). In terms of its biomechanics, DAI is occurring as a result of acceleration forces of longer duration and has been fully reproduced experimentally.In the process of diagnosing DAI, the performance of a complete forensic neuropathological examination is essential and the immunohistochemistry method using antibodies against ß-amyloid precursor protein (ß-APP) has been proved to be highly sensitive and specific, selectively targeting the damaged axons.In this review, we are pointing to the significant characteristics of DAI as a distinct clinicopathological entity that can cause severe impairment of the brain function, and in the forensic medicine setting, it can be found as the concrete cause of death. We are discussing not only its pathological feature, its mechanism of occurrence, and the events on a cellular level but also the dilemmas about DAI that still exist in science: (1) regarding the strict criteria for its diagnosis and (2) regarding its biomechanical significance, which can be of a big medicolegal importance.
Asunto(s)
Lesión Axonal Difusa/diagnóstico , Traumatismos Cerrados de la Cabeza/complicaciones , Aceleración , Precursor de Proteína beta-Amiloide/metabolismo , Axones/metabolismo , Biomarcadores/metabolismo , Fenómenos Biomecánicos , Lesión Axonal Difusa/clasificación , Patologia Forense , Humanos , InmunohistoquímicaRESUMEN
Dilemmas and discussions concerning the diffuse axonal injury (DAI) and still existing in forensic medical practice are as it follows: 1. Whether the occurrence of DAI can indicate the type of traumatic event that has caused the head trauma, 2. Whether the presence of axonal damage in cases of hypoxia, ischaemia and other pathological conditions casts a shadow on the post-mortem pathological diagnosis of DAI and totally negates it, or there are certain clues in the findings that can point to the aetiology of the axonal damage. This paper discusses our findings based on neuropathological examination of 60 forensic cases of closed head injury. The neuropathological examination included: a macroscopic examination of the coronal sections and a microscopic examination involving an immunohistochemical method with antibody against ß-amyloid precursor protein. Our findings indicate that DAI, as a clinicopathological entity, is undoubtedly an acceleration-deceleration injury, predominant in road traffic accidents as it is classically outlined, and cases of falling from a considerable height. Our findings point to a certain difference between the features of traumatic and ischaemic axonal damage. In this paper we also investigate the correlation between pathological grades of DAI and the impairment of the brain function before death.
Asunto(s)
Lesión Axonal Difusa/patología , Traumatismos Cerrados de la Cabeza/mortalidad , Accidentes por Caídas/mortalidad , Accidentes de Tránsito/mortalidad , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Precursor de Proteína beta-Amiloide/metabolismo , Encéfalo/metabolismo , Encéfalo/patología , Niño , Coma/epidemiología , Lesión Axonal Difusa/clasificación , Femenino , Patologia Forense , Escala de Coma de Glasgow , Humanos , Inmunohistoquímica , Puntaje de Gravedad del Traumatismo , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
Traumatic brain injury (TBI) is the most common cause of death and disability in young people. The functional outcome in patients with TBI cannot be explained by focal pathology alone, and diffuse axonal injury (DAI) is considered a major contributor to the neurocognitive deficits experienced by this group. The aim of the present study was to investigate whether diffusion tensor imaging (DTI) offers additional information as to the extent of damage not visualized with standard magnetic resonance imaging (MRI) in patients with severe TBI. Nine chronic male TBI patients and 11 matched healthy controls were recruited. Results of the voxel-based analysis of fractional anisotropy (FA) maps and apparent diffusion coefficient (ADC) maps revealed significant differences in anisotropy in major white matter tracts, including the corpus callosum (CC), internal and external capsule, superior and inferior longitudinal fascicles, and the fornix in the TBI group. The FA and ADC measurements offered superior sensitivity compared to conventional MRI diagnosis of DAI. Region-of-interest (ROI) analyses confirmed these results in the investigated regions. The findings of this study support the hypothesis that severe TBI is accompanied by DAI. The DTI changes were more prominent on the right side that contained the focal pathology in most of the patients and accurately reflected differences in both hemispheres. In conclusion, DTI holds great promise as a diagnostic tool to identify and quantify the degree of white matter injury in TBI patients.
Asunto(s)
Lesiones Encefálicas/diagnóstico , Encéfalo/patología , Lesión Axonal Difusa/diagnóstico , Imagen de Difusión por Resonancia Magnética/métodos , Adulto , Síntomas Afectivos/diagnóstico , Síntomas Afectivos/etiología , Síntomas Afectivos/patología , Anisotropía , Axones/patología , Encéfalo/fisiopatología , Lesiones Encefálicas/clasificación , Lesiones Encefálicas/fisiopatología , Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/etiología , Trastornos del Conocimiento/patología , Cuerpo Calloso/patología , Cuerpo Calloso/fisiopatología , Lesión Axonal Difusa/clasificación , Lesión Axonal Difusa/fisiopatología , Diagnóstico Precoz , Lateralidad Funcional/fisiología , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Masculino , Fibras Nerviosas Mielínicas/patología , Vías Nerviosas/patología , Vías Nerviosas/fisiopatología , Valor Predictivo de las PruebasRESUMEN
BACKGROUND AND PURPOSE: Multiple biomarkers are used to quantify the severity of traumatic brain injury (TBI) and to predict outcome. Few are satisfactory. CT and conventional MR imaging underestimate injury and correlate poorly with outcome. New MR imaging techniques, including diffusion tensor imaging (DTI), can provide information about brain ultrastructure by quantifying isotropic and anisotropic water diffusion. Our objective was to determine if changes in anisotropic diffusion in TBI correlate with acute Glasgow coma scale (GCS) and/or Rankin scores at discharge. METHODS: Twenty patients (15 male, five Female; mean age, 31 years) were evaluated. Apparent diffusion coefficients (ADCs) and fractional anisotropy (FA) values were measured at multiple locations and correlated with clinical scores. Results were compared with those of 15 healthy control subjects. RESULTS: ADC values were significantly reduced within the splenium (Delta18%, P =.001). FA values were significantly reduced in the internal capsule (Delta14%; P <.001) and splenium (Delta16%; P =.002). FA values were significantly correlated with GCS (r = 0.65-0.74; P <.001) and Rankin (r = 0.68-0.71; P <.001) scores for the internal capsule and splenium. The correlation between FA and clinical markers was better than for the corresponding ADC values. No correlation was found between ADC of the internal capsule and GCS/Rankin scores. CONCLUSION: DTI reveals changes in the white matter that are correlated with both acute GCS and Rankin scores at discharge. DTI may be a valuable biomarker for the severity of tissue injury and a predictor for outcome.