Hyperpolarized 3He NMR lineshape measurements in the live guinea pig lung.
Spatially localized lineshapes of hyperpolarized (HP) 3He in guinea pig lungs have been measured in vivo. Three different axial slice locations, each containing different compositions of airway sizes and orientations, were studied. Gas peaks from major bronchi (2 ppm) and alveoli (-2 ppm) were distinguished. The gas phase spectra show structural features that are a result of frequency shifts caused by bulk magnetic susceptibility. For a given slice, the spectral lineshapes reflect the airway composition within the slice location, according to theory. The peak assignments given here also agree with previous studies done by Wagshul et al. with HP 129Xe. At each of the slice locations, data were acquired during two phases of the breathing cycle, resulting in a relative frequency shift of approximately 0.3 ppm in the superior slices. Spectra obtained over a number of breaths show the dynamics of the gas buildup in the lung and provide further evidence supporting the peak assignments.
Chen
X J
XJ
Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina 27710, USA.
Chawla
M S
MS
Cofer
G P
GP
Hedlund
L W
LW
Möller
H E
HE
Johnson
G A
GA
D000818:Animals; D006168:Guinea Pigs; D006371:Helium; D007554:Isotopes; D008168:Lung / Q000033:anatomy & histology*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011659:Pulmonary Gas Exchange; D012016:Reference Values; D015656:Respiratory Mechanics; D012680:Sensitivity and Specificity
D007554:Isotopes; D006371:Helium