Imaging of lung ventilation and respiratory dynamics in a single ventilation cycle using hyperpolarized He-3 MRI.
OBJECTIVE
To image respiratory dynamics and three-dimensional (3D) ventilation during inhalation, breath-hold, and exhalation for evaluation of obstructive lung disease using a single dose of hyperpolarized (HP) He-3 during MRI.


METHODS
A single 2D-3D projections inside Z encoding (PRIZE)-2D acquisition was performed that consisted of a rapid 2D radial acquisition phase during inhalation of the HP He-3, a 3D acquisition phase during a breath-hold interval, and finally the same 2D radial acquisition during a forced exhalation maneuver followed by tidal breathing. The 3D PRIZE acquisition was comprised of radial sampling in the coronal plane and Fourier encoding in the patient's anterior-posterior direction. Nine patients with mild/moderate to severe asthma were studied (two individuals were studied twice) using this technique.


RESULTS
Breath-hold and dynamic imaging results showed physiological abnormalities and were compared with results from standard spirometry, body plethysmography, and computed tomography (CT). Dynamic images depicted regions of differential gas clearance and trapping observed during and after forced exhalation that were corroborated as regions of air trapping on CT imaging.


CONCLUSIONS
The 2D-3D PRIZE-2D acquisition allowed for 3D depiction of ventilation during a breath-hold, as well as detection of gas trapping. Imaging results were confirmed with spirometry, body plethysmography, and CT.
Holmes
James H
JH
Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Korosec
Frank R
FR
Du
Jiang
J
O'Halloran
Rafael L
RL
Sorkness
Ronald L
RL
Grist
Thomas M
TM
Kuhlman
Janet E
JE
Fain
Sean B
SB
D000388:Air; D001249:Asthma / Q000473:pathology; D003287:Contrast Media / Q000494:pharmacology; D005583:Fourier Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional; D008168:Lung / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012119:Respiration; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods
D003287:Contrast Media