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Rapid imaging of hyperpolarized gas using EPI
B Saam1, D A Yablonskiy, D S Gierada
1Department of Physics, Washington University, St. Louis, Missouri, USA.
Magnetic Resonance in Medicine
|September 1, 1999
Summary
This study demonstrates that rapid, repetitive magnetic resonance imaging (MRI) of hyperpolarized helium-3 (HP-He-3) gas in the human lung is feasible. The technique provides real-time visualization of ventilation, offering a new tool for respiratory research.
Area of Science:
- Medical Imaging
- Pulmonary Medicine
- Magnetic Resonance Imaging
Background:
- Hyperpolarized (HP) gases, such as helium-3 (He-3), enable novel Magnetic Resonance Imaging (MRI) applications.
- Echo-planar imaging (EPI) allows for rapid image acquisition, crucial for dynamic physiological processes.
Purpose of the Study:
- To investigate the feasibility of rapid, repetitive MRI of HP-He-3 gas in the human lung.
- To develop and implement an EPI pulse sequence for real-time lung ventilation imaging.
Main Methods:
- Theoretical investigation and experimental demonstration of rapid repetitive EPI for HP-He-3 lung MRI.
- Development of a coarse-grid (32 x 64) EPI pulse sequence.
- Imaging of healthy volunteers during rebreathing of an HP-He-3/N(2) gas mixture, acquiring 3 axial slices every 0.12 seconds.
Main Results:
- Demonstrated feasibility of rapid, repetitive HP-He-3 lung MRI using low flip angles.
- Achieved real-time visualization of lung ventilation during a 36-second rebreathing period.
- Images showed good quality with detectable changes in gas density related to respiratory physiology.
Conclusions:
- Rapid repetitive EPI of HP-He-3 gas is a viable technique for real-time lung ventilation imaging.
- The developed imaging method provides insights into respiratory physiology.
- Further optimization may reduce mild artifacts observed in the images.