Investigating 3He diffusion NMR in the lungs using finite difference simulations and in vivo PGSE experiments.
Finite difference simulations have been used to model (3)He gas diffusion in simulated lung tissue. The technique has the advantage that a wide range of structural models and diffusion-sensitizing gradient waveforms can be investigated, for which analytical methods would otherwise be virtually impossible. Results from simulations and in vivo pulsed-gradient-spin-echo (PGSE) experiments show that the apparent diffusion coefficient (ADC) is a function of diffusion time and gradient strength, and suggests diffusion is locally anisotropic. The simulations have been compared to recent work on an analytical model that characterizes lung tissue as a series of independent cylinders. The results presented may have clinical implications for (3)He ADC measurements in assessing lung diseases such as chronic-obstructive-pulmonary-disease.
Academic Unit of Radiology, The University of Sheffield, Royal Hallamshire Hospital, Glossop Road, Sheffield S10 2JF, England, UK. s.fichele@sheffield.ac.uk
Stanislao
S
Fichele
Martyn N J
MN
Paley
Neil
N
Woodhouse
Paul D
PD
Griffiths
Edwin J R
EJ
van Beek
Jim M
JM
Wild
D000328:Adult; D000465:Algorithms; D003198:Computer Simulation; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006371:Helium / Q000493:pharmacokinetics*; D006801:Humans; D007554:Isotopes / Q000493:pharmacokinetics; D008168:Lung / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D009716:Numerical Analysis, Computer-Assisted; D011659:Pulmonary Gas Exchange; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012907:Smoking / Q000378:metabolism
D007554:Isotopes; D019275:Radiopharmaceuticals; D006371:Helium