Spatially resolved measurements of hyperpolarized gas properties in the lung in vivo. Part II: T *(2).
The transverse relaxation time, T *(2), of hyperpolarized (HP) gas in the lung in vivo is an important parameter for pulse sequence optimization and image contrast. We obtained T *(2) maps of HP (3)He and (129)Xe in guinea pig lungs (n = 17) and in human lungs. Eight different sets of (3)He guinea pig studies were acquired, with variation of slice selection, tidal volume, and oxygen level. For example, for a (3)He tidal volume of 3 cm(3) and no slice selection, the average T *(2) in the trachea was 14.7 ms and 8.0 ms in the intrapulmonary airspaces. The equivalent (129)Xe experiment yielded an average T *(2) of 40.8 ms in the trachea and 18.5 ms in the intrapulmonary airspaces. The average (3)He T *(2) in the human intrapulmonary airspaces was 9.4 ms. The relaxation behavior was predicted by treating the lung as a porous medium, resulting in good agreement between estimated and measured T *(2) values in the intrapulmonary airspaces. Magn Reson Med 42:729-737, 1999.
Chen
X J
XJ
Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina 27710, USA.
Möller
H E
HE
Chawla
M S
MS
Cofer
G P
GP
Driehuys
B
B
Hedlund
L W
LW
MacFall
J R
JR
Johnson
G A
GA
D000818:Animals; D006168:Guinea Pigs; D006371:Helium; D006801:Humans; D007554:Isotopes; D008168:Lung / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011653:Pulmonary Diffusing Capacity; D014132:Trachea / Q000033:anatomy & histology; D014979:Xenon Isotopes
D007554:Isotopes; D014979:Xenon Isotopes; D006371:Helium