Optical Cell Beam Polarizer Purifier
Cell Inlet Valve
Cell Outlet Valve
High Powered Laser Diode Array
Supply Regulator
Flow Meter
Polarized Gas Compatible Regulator
Xe , He , N 2 Mix tu re
He/N 2 Vent
Xe Flow Control Valve
Xe Flow Shut-Off Valve
Inspiration Control Valves
Pressure Transducer
Specimen's Lungs
Supply Regulators
Expiration Control Valve
Flow Restrictors
Valve Automation
1A
2A
3A
4A
5A
1B
2B
3B
4B
5B
Figure 2 Images of rats using standard ventilation (1A-5A) and continuous delivery (1B-5B).
Results and Discussion: For standard versus direct delivery, we achieved resolutions of 0.31×0.31mm2 with SNR of 10-21 versus 1.09×1.09mm2 with SNR of 7.5-15, reflecting a factor of 23 signal difference. Most notably, the direct flow images were acquired in 0.83min using only 0.8ml of Xe, whereas the standard images were acquired using 64ml Xe. The direct-flow images are of sufficient quality to delineate the major airways and observe the shrunken ventilated volume in the fibrotic lungs (3B-5B).
Conclusion: In its current form, this technique is very useful for performing some of the standard pre-scan activities such as localizing, shimming, setting flip angle and frequency, or pulse sequence testing. More interesting, however, is the possibility of concentrating the 129Xe to 100% in real time, gaining a further factor of 100 and enabling high-resolution129Xe imaging beyond the lung to become practical. References 1. M. Haake, A. Pines, J. A. Reimer et al., Journal Of The American Chemical Society 119 (48), 11711-11712 (1997). 2. B. T. Chen, A. C. Brau, and G. A. Johnson, Magnetic Resonance in Medicine 49 (1), 78-88 (2003). Acknowledgments NCRR P41 05959, NHLBI 2R01HL55348, The GEMI fund.
Proc. Intl. Soc. Mag. Reson. Med. 14 (2006)
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