Flip angle considerations in (3)helium-MRI.
3Helium-MRI ((3)He-MRI) can be used for analysis of lung function, e. g. dynamic imaging of ventilation and gas diffusion within the lung, assessment of intrapulmonary oxygen concentrations and their time course. During imaging, the irreversible signal loss due to depolarizing radio frequency excitations can be described using the flip angle (FA) alpha. This parameter has to be quantified in order to account for it during quantitative assessment of the (3)helium signal intensity and its temporal development. This technical report reviews two different methods to determine alpha. Limitations and possible error sources of each method are discussed.
Markstaller
K
K
Department of Anaesthesiology, Johannes Gutenberg-University Mainz, Langenbeckstr 1, 55131 Mainz, Germany. klm@mail.uni-mainz.de
Eberle
B
B
Schreiber
W G
WG
Weiler
N
N
Thelen
M
M
Kauczor
H U
HU
D003198:Computer Simulation; D006371:Helium; D006801:Humans; D007554:Isotopes; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010100:Oxygen / Q000032:analysis; D012129:Respiratory Function Tests / Q000379:methods*; D013990:Tidal Volume
D007554:Isotopes; D006371:Helium; D010100:Oxygen