Rapid hyperpolarized 3He diffusion MRI of healthy and emphysematous human lungs using an optimized interleaved-spiral pulse sequence.
OBJECTIVE
To develop and validate an interleaved-spiral diffusion pulse sequence capable of hyperpolarized (3)He MR imaging of the whole lung in less than 10 seconds.


METHODS
Hyperpolarized (3)He diffusion measurements were performed in seven healthy volunteers and five patients with emphysema using an interleaved-spiral pulse sequence that provided 11 contiguous 15-mm thick coronal ADC maps, with an in-plane resolution of 3.9 mm, covering the whole lung in 5.5 seconds. The resulting means and SDs of ADC values were compared statistically to those from a gradient-echo pulse sequence with identical resolution and diffusion-weighting gradients that acquired five ADC maps in 10.5 seconds.


RESULTS
High-quality diffusion-weighted interleaved-spiral images covering the whole lung were obtained, and showed no significant susceptibility-induced image degradation compared to corresponding gradient-echo images. On a subject-by-subject basis, the means and SDs of ADC values for the interleaved-spiral technique were not statistically different from those for the gradient-echo technique. The mean ADC values from the two techniques were highly correlated on a section-by-section basis (R = 0.99).


CONCLUSIONS
The interleaved-spiral diffusion pulse sequence permits rapid acquisition of contiguous ADC maps covering the whole lung during a short breath-hold period, and provides ADC values that are statistically equivalent to those from standard gradient-echo techniques.
Center for In-Vivo Hyperpolarized Gas MR Imaging, Department of Radiology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.
Michael
M
Salerno
Talissa A
TA
Altes
James R
JR
Brookeman
Eduard E
EE
de Lange
John P
JP
Mugler
D000328:Adult; D000368:Aged; D003287:Contrast Media; D004646:Emphysema / Q000175:diagnosis*; D005260:Female; D006371:Helium; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008168:Lung / Q000033:anatomy & histology* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical
D003287:Contrast Media; D006371:Helium