Young Investigator Award Oral Presentations
Click on to view the abstract pdf and click on to view the video presentation.
Monday May 9th
Room 710A  14:00 - 16:00 Moderators:  

14:00 94.   Magnetic Resonance Elastography of Human Lung Parenchyma: Technical development, theoretical modeling and in vivo validation  
Yogesh kannan Mariappan1, Kevin Glaser1, Rolf D Hubmayr2, Armando Manduca1, Richard L Ehman1, and Kiaran P McGee1
1Department of Radiology, Mayo Clinic, Rochester, MN, United States, 2Department of Pulmonary and Critical Care medicine, Mayo Clinic, Rochester, MN, United States

The purpose of this work was to develop magnetic resonance elastography (MRE) for in vivo assessment of human lung. A modified 1H spin echo MRE pulse sequence providing a short TE of 9.4 ms was used to acquire human lung MRE data at the residual volume and the total lung capacity in 10 healthy volunteers. MRE-based density corrected stiffness values at TLC were significantly higher than those at the RV. These data indicate that 1H-based MRE can noninvasively measure the shear stiffness of lung parenchyma in vivo and can differentiate shear stiffnesses at differing respiratory states.

14:20 95.   Hyperpolarized Xenon-129 Gas-Exchange Imaging of Lung Microstructure: Preliminary Results in Subjects with Obstructive Lung Disease 
Isabel Dregely1, John P Mugler III2, Iulian Constantin Ruset3, Talissa A Altes2, Jamie F Mata2, G. Wilson Miller2, Jeffrey Ketel3, Steve Ketel3, Jan Distelbrinck3, F William Hersman1,3, and Kai Ruppert2
1Physics, University of New Hampshire, Durham, NH, United States, 2Radiology, University of Virginia, Charlottesville, Virginia, United States, 3Xemed LLC, Durham, NH, United States

The purpose of this study was to develop and test a method, Multiple exchange time Xenon polarization Transfer Contrast (MXTC) MRI, to non-invasively assess lung microstructure. The dynamic encoding of the xenon gas-exchange contrast permits two parameters to be derived regionally which are related to gas-exchange functionality by characterizing the tissue to alveolar-volume ratio and the alveolar wall thickness. By quantifying simultaneously two lung function parameters, MXTC provides a more comprehensive picture of lung microstructure then existing lung imaging techniques and could become an important non-invasive and quantitative tool to characterize pulmonary disease phenotypes.

14:40 96.   3D+t Biventricular Strain from Tagged Magnetic Resonance Images by Phase-Unwrapped HARP 
Bharath Ambale Venkatesh1, Himanshu Gupta2, Steven G. Lloyd3, Louis Dell' Italia3, and Thomas S. Denney Jr.4
1Electrical and Computer Engineering, Auburn University, Auburn, Alabama, United States, 2University of Alabama at Birmingham, United States, 3University of Alabama at Birmingham, 4Auburn University

Accurate assessment of ventricular function is clinically important. In this abstract, a method for reconstructing three-dimensional biventricular strain over time from unwrapped harmonic phase measurements is validated in normal volunteers and patients. The strain obtained is compared to 3D strain obtained from a feature-based method and 2D strain obtained from harmonic phase strain measurements.

15:00 97.   Multi-Coil Shimming of the Mouse Brain 
Christoph Juchem1, Peter B Brown1, Terence W Nixon1, Scott McIntyre1, Douglas L Rothman1, and Robin A de Graaf1
1MR Research Center, Yale University, New Haven, CT, United States

The magnetic homogenization of the mouse brain with dynamically updated multi-coil fields is presented. The novel MC concept enabled the flexible and accurate generation of complex magnetic field shapes that allowed largely improved magnetic field homogenization of the mouse brain at 9.4 Tesla compared to conventional spherical harmonics shimming. The multi-coil shimming technique paves the way for MR applications of the mouse brain as a whole of parts thereof for which excellent magnetic field homogeneity is a prerequisite.

15:20 98.   Double-PFG MR as a novel means for characterizing microstructures in grey matter 
Noam Shemesh1, Ofer Sadan2, Daniel Offen3, and Yoram Cohen1
1School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel, 2Department of Neurology, Tel-Aviv Medical Center and the Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel, 3Laboratory of Neurosciences, Felsenstein Medical Research Center, Department of Neurology, Rabin Medical center, Israel

Double-Pulsed-Field-Gradient (d-PFG) MR is emerging as a promising methodology for characterizing underlying microstructural features in randomly oriented anisotropic compartments, which are difficult to characterize using conventional diffusion MR methods. Here, d-PFG spectroscopy was performed on isolated pig grey matter (GM). Angular dependencies in the E() plots were observed, indicating the presence of compartment shape and microscopic anisotropies in the grey matter. Angular d-PFG MRI was then performed in the rat brain ex-vivo, showing that different GM regions indeed yield different angular patterns, thus reporting on different underlying microstructures within the GM. Therefore, d-PFG MRI is promising for characterizing GM tissues.

15:40 99.   Low-dimensional-Structure Self-Learning and Thresholding (LOST): Regularization Beyond Compressed Sensing for MRI Reconstruction 
Mehmet Akcakaya1, Tamer Basha1, Beth Goddu1, Lois Goepfert1, Kraig V. Kissinger1, Vahid Tarokh2, Warren J. Manning1, and Reza Nezafat1
1Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, 2School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States

We develop an improved image reconstruction technique for undersampled acquisitions that learns and utilizes the structure of images being reconstructed. The results of our retrospective study with coronary MRI imply that the proposed method achieves higher acceleration rates compared to conventional CS reconstructions. The pilot prospective acquisitions confirm this finding, and additionally show that our method provides superior image quality at higher rates compared to traditional parallel imaging reconstruction.