Arterial spin tagging perfusion imaging of rat brain: dependency on magnetic field strength.
Magn Reson Imaging
; 18(9): 1109-13, 2000 Nov.
Article
en En
| MEDLINE
| ID: mdl-11118765
Perfusion-weighted imaging (PWI), using the method of arterial spin tagging, is strongly T(1)-dependent. This translates into a high field dependency of the perfusion signal intensity. In order to determine the expected signal improvement at higher magnetic fields we compared perfusion-weighted images in rat brain at 4.7 T and 7 T. Application of PWI to focal ischemia and functional activation of the brain and the use of two different anesthetics allowed the observation of a wide range of flow values. For all these (patho-)physiological conditions switching from 4.7 T to 7 T resulted in a significant increase of mean perfusion signal intensity by a factor of 2.96. The ratio of signal intensities of homotopic regions in the ipsi- and contralateral hemisphere was field-independent. The relative contribution of a) T(1) relaxation time, b) net magnetization, c) the Q-value of the receiver coils and d) the degree of adiabatic inversion to the signal improvement at higher field strength were discussed. It was shown that the main parameters contributing to the higher signal intensity are the lengthening of T(1) and the higher magnetization at the higher magnetic field.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Imagen por Resonancia Magnética
/
Isquemia Encefálica
/
Circulación Cerebrovascular
Límite:
Animals
Idioma:
En
Revista:
Magn Reson Imaging
Año:
2000
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Países Bajos