Quantitative measurement of regional lung ventilation using 3He MRI.
A new strategy for a quantitative measurement of regional pulmonary ventilation using hyperpolarized helium-3 (3He) MRI has been developed. The method employs the build-up of the signal intensity after a variable number of (3)He breaths. A mathematical model of the signal dynamics is presented, from which the local ventilation, defined as the fraction of gas exchanged per breath within a given volume, is calculated. The model was used to create ventilation maps of coronal slices of guinea pig lungs. Ventilation values very close to 1 were found in the trachea and the major airways. In the lung parenchyma, regions adjacent to the hilum showed values of 0.6-0.8, whereas 0.2-0.4 was measured in peripheral regions. Monte Carlo simulations were used to investigate the accuracy of the method and its limitations. The simulations revealed that, at presently attainable signal-to-noise ratios, the ventilation parameter can be determined with a relative uncertainty of <5% over a wide range of values.
Deninger
Anselm J
AJ
Amersham Health R&D, Medeon, SE - 205 12 Malmö, Sweden.
Månsson
Sven
S
Petersson
J Stefan
JS
Pettersson
Göran
G
Magnusson
Peter
P
Svensson
Jonas
J
Fridlund
Björn
B
Hansson
Georg
G
Erjefeldt
Ingrid
I
Wollmer
Per
P
Golman
Klaes
K
D000818:Animals; D006168:Guinea Pigs; D006371:Helium; D007091:Image Processing, Computer-Assisted; D007554:Isotopes; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011659:Pulmonary Gas Exchange; D012123:Pulmonary Ventilation / Q000502:physiology; D012680:Sensitivity and Specificity
D007554:Isotopes; D006371:Helium