Long-range diffusion of hyperpolarized 3He in explanted normal and emphysematous human lungs via magnetization tagging.
J Appl Physiol (1985)
; 99(5): 1992-7, 2005 Nov.
Article
en En
| MEDLINE
| ID: mdl-16024528
ABSTRACT
Long-range diffusivity of hyperpolarized 3He gas was measured from the decay rate of sinusoidally modulated longitudinal nuclear magnetization in three normal donor and nine severely emphysematous explanted human lungs. This (long-range) diffusivity, which we call Dsec, is measured over seconds and centimeters and is approximately 10 times smaller in healthy lungs (0.022 cm2/s) than the more traditionally measured Dmsec, which is measured over milliseconds and submillimeters. The increased restriction of Dsec reflects the complex, tortuous paths required to navigate long distances through the maze of branching peripheral airways. In emphysematous lungs, Dsec is substantially increased, with some regions showing nearly the unrestricted value of the self-diffusion coefficient (0.88 cm2/s for dilute 3He in air, a 40-fold increase). This suggests the presence of large collateral pathways opened by alveolar destruction that bypass the airways proper. This destruction was confirmed by comparison with histology in seven lungs and by removal of trapped gas via holes in the pleural surface in five lungs.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Imagen por Resonancia Magnética
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Enfisema
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Helio
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Isótopos
Límite:
Humans
Idioma:
En
Revista:
J Appl Physiol (1985)
Asunto de la revista:
FISIOLOGIA
Año:
2005
Tipo del documento:
Article
País de afiliación:
Estados Unidos