Traditional Posters: Body Imaging
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| Mirko I. Hrovat1, Iga Muradian2, Eric Frederick3, James P. Butler4, Hiroto Hatabu2, Samuel Patz2
1Mirtech, Inc., Brockton, MA, United States; 2Radiology, Brigham and Women's Hospital, Boston, MA, United States; 3Dept. of Physics, University of Masachusetts at Lowell, Lowell, MA, United States; 4Harvard School of Public Health, Boston, MA, United States A theoretical model is presented to understand the XTC experiment with hyperpolarized 129Xe for arbitrary flip angle. The model is flexible in that different dissolved state diffusion models may be incorporated. The model also illustrates fundamental differences between CSSR and XTC experiments. It is clear that no single exchange time value dominates the time evolution of the XTC signal. It is demonstrated that the XTC90 experiment (employing 90° flips instead of 180°) should generate results similar to CSSR experiments. 2557. Lung Inflation State Dominates Over Intrapulmonary PO2 Regarding T2* of 3He in Human Lungs Martin H. Deppe1, Salma Ajraoui1, Helen Marshall1, Jim M. Wild1 1Academic Radiology, University of Sheffield, Sheffield, Yorkshire, United Kingdom This work investigates the influence of O2 on the T2* of hyperpolarized 3He in human lungs. To separate the effect of O2 from the known lung inflation dependence, T2* maps were obtained at expiration and full inspiration, both at baseline breathing air and after 4 min of pure O2. It is found that the effect of lung inflation dominates over any potential O2 effect, which is proposed to be due to a combination of motional narrowing and the fact that 3He is distributed over the whole alveolus, while 1H spins are confined to the interfaces, where susceptibility gradients are strongest. 2558. Motion-Corrected PO2 Mapping in Human Lungs Using Hyperpolarized Xe-129 MRI G. Wilson Miller1, John P. Mugler III1, Talissa A. Altes1, Isabel Dregely2, Iulian Ruset3, Steve Ketel3, Jeff Ketel3, William F. Hersman2,3, Kai Ruppert1 1Radiology, University of Virginia, Charlottesville, VA, United States; 2Physics, University of New Hampshire, Durham, NH; 3Xemed LLC, Durham, NH Lung pO2 mapping using hyperpolarized Xe-129 was performed in 6 healthy volunteers and 4 disease patients. An image registration algorithm was used to correct for subject motion during the breath hold acquisition. 2559. An Integrated Small-Animal Ventilator and Recycling System for Small-Animal Hyperpolarized Gas MRI John C. Nouls1, Manuel Fanarjian2, Bastiaan Driehuys1,3 1Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States; 2Biomedical Engineering, Duke University, Durham, NC, United States; 3Radiology, Duke University Medical Center We present a constant-volume small-animal ventilator that offers precise control of gas delivery, permits high-resolution hyperpolarized gas imaging, and captures the exhaled mixture containing 3He or 129Xe for recycling. The captured gas is compressed by a piston and stored in a cylinder to be sent for re-purification. The same ventilator can ventilate different small animals, simply by changing flow constrictors. The ventilator is inexpensive to duplicate and only uses off-the shelf components. By recapturing exhaled gas, it alleviates some of the costs associated with HP gas imaging. 2560. Hyperpolarized Noble Gas MR Imaging SNR Comparison Between 73.5 MT and 3 T in Rat Lung Yüklə 458,11 Kb. Dostları ilə paylaş:
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