Evolution of hippocampal CA-1 diffusion lesions in transient global amnesia.
Ann Neurol
; 62(5): 475-80, 2007 Nov.
Article
em En
| MEDLINE
| ID: mdl-17702037
ABSTRACT
OBJECTIVE:
Selective focal MR-Signal (diffusion-) changes in the CA-1 sector of the hippocampus have been described in transient global amnesia (TGA), but the pathophysiological substrate of these lesions is largely unknown. As several imaging and epidemiological findings point to a vascular origin an analysis of the temporal evolution of the hippocampal apparent diffusion coefficient (ADC) changes may offer new understanding of the pathomechanisms of TGA.METHODS:
The time course of the ADC of hippocampal DWI lesions in TGA patients was studied using serial 3 T high-resolution MR-imaging within 1-10 days as well as 4-6 months after TGA. ADC values from 76 MR-studies were analyzed and expressed as ratio ADC (rADC) in reference to the unaffected hemisphere.RESULTS:
Twenty-nine patients with TGA showed 34 DWI lesions with corresponding T2 lesions in the CA-1 sector of the hippocampal cornu ammonis within a time window of 24-72 h after onset. Ratio ADC decreased below 1.0 (0.66 +/- 0.08) 24 h after the acute TGA episode and did show a further significant decrease to 0.57 +/- 0.1 after 3 days (p < 0.05). After 72 h, rADC increased and normalized around day 10 with rADC values of 1.0 (p < 0.05).INTERPRETATION:
The temporal evolution of the rADC in hippocampal signal changes in TGA shows a time course previously described for ischemic lesions in human stroke patients. This might imply a vascular origin of diffusion changes leading to a transient perturbation of memory relevant circuits in the hippocampus.
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Base de dados:
MEDLINE
Assunto principal:
Amnésia Global Transitória
/
Imagem de Difusão por Ressonância Magnética
/
Hipocampo
Limite:
Adult
/
Aged
/
Humans
/
Middle aged
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article