Extending the range of diffusion times for regional measurement of the 3He ADC in human lungs.
A stimulated-echo-based technique was developed to measure the regional apparent diffusion coefficient (ADC) of hyperpolarized 3He during a single breathhold for diffusion times of 25 ms or greater. Compared to previous methods, a substantially shorter minimum diffusion time was achieved by decoupling diffusion sensitization from image acquisition. A hyperpolarized-gas phantom was used to validate the method, which was then tested in four healthy subjects in whom regional ADC maps were acquired with diffusion times of 50, 200, and 1500 ms and a tag wavelength of 5 or 10 mm. ADC values from healthy subjects were in good agreement with reported literature values and decreased with increasing diffusion time. Mean ADC values were approximately 0.07, 0.03, and 0.015 cm2/s for diffusion times of 50, 200, and 1500 ms, respectively. ADC maps were generally homogeneous, with similar mean values when measured with the same parameters in different subjects.
Wang
Chengbo
C
Center for In-vivo Hyperpolarized Gas MR Imaging, Department of Radiology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.
Miller
G Wilson
GW
Altes
Talissa A
TA
de Lange
Eduard E
EE
Cates
Gordon D
GD
Mata
Jaime F
JF
Brookeman
James R
JR
Mugler
John P
JP
D001249:Asthma / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006371:Helium; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007554:Isotopes; D008168:Lung / Q000033:anatomy & histology*; D008297:Male; D019047:Phantoms, Imaging
D007554:Isotopes; D006371:Helium