Young Investigator Award Presentations

Monday 12 May 2014

Peng Cao^1,2, Shu-Juan J. Fan^1,2, Anna M. Wang^1,2, Victor B. Xie^1,2, Zhongwei Qiao^1,2, Gary M. Brittenham³, and Ed X. Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong, China, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China, ³Departments of Pediatrics and Medicine, Columbia University College of Physicians and Surgeons, New York, NY, United States

Intramyocellular lipid (IMCL) droplets are dynamic organelles whose morphology reflects their vital roles in lipid synthesis, utilization and storage in muscle energy metabolism. To develop non-invasive means to measure droplet microstructure in vivo, we investigated the molecular diffusion behavior of IMCL with diffusion MR spectroscopy. Our results demonstrate the feasibility of MR diffusion characterization of IMCL droplet microstructure and provide evidence of the sensitivity of this method to metabolic alterations. The use of diffusion MR methodology in vivo promises to provide new biophysical insights in the investigation of droplet dynamics and lipid metabolism in both animal models and human subjects. The diffusion MR results may help contribute to an improved understanding and diagnosis of obesity, diabetes and other metabolic disorders.

Clarissa Zimmerman Cooley^1,2, Jason P. Stockmann^1,3, Brandon D. Armstrong^1,3, Mathieu Sarracanie^1,3, Michael H. Lev^4,5, Matthew S. Rosen^1,3, and Lawrence L. Wald^1,5
1A. A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, United States, ²Dept. of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, ³Dept. of Physics, Harvard University, Cambridge, MA, United States, ⁴Dept. of Radiology, Massachusetts General Hospital, Boston, MA, United States, ⁵Harvard Medical School, Boston, MA, United States

As the premiere modality for brain imaging, MRI could find wider applicability if lightweight, portable systems were available for siting in unconventional locations. We construct and validate a truly portable (<100kg) and silent proof-of-concept scanner which replaces conventional gradient encoding with a rotating lightweight low-field magnet. When rotated about the object, the inhomogeneous field pattern is used to create generalized projections which encode the iteratively reconstructed 2D image. The system is validated with experimental images of 2D test phantoms. This new scanner architecture demonstrates the potential for portability by simultaneously relaxing the magnet homogeneity criteria and eliminating the gradient coil.

Hisham Z. Bajwa¹, Lois Do¹, Mohammed Suhail¹, Steve W. Hetts¹, Mark W. Wilson¹, and Maythem Saeed^1
1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, United States

Our study was aimed at providing direct evidence that mechanical obstruction of microvessels in the coronary vasculature inhibits myocardial infarct resorption and enhances LV remodeling using MRI and then confirming these findings with histopathology. We found that persistent microvascular obstruction after 3 days was larger on average and more frequently found in animals that underwent LAD occlusion/microemboli delivery/reperfusion than animals that were only subjected to occlusion/reperfusion. The greater microvascular obstruction in the former was associated with less infarct resorption, a greater degree of increase in LV mass and more pronounced decline in LV ejection fraction.

Thomas Christen¹, Hesamoddin Jahanian¹, Wendy Wei Ni¹, Deqiang Qiu¹, Michael E Moseley¹, and Greg Zaharchuk^1
1Department of Radiology, Stanford University, Stanford, California, United States

In this work, we investigated if delays in resting-state spontaneous fluctuations of the BOLD (sfBOLD) signal can be used to create maps similar to time-to-maximum of the residue function (Tmax) in Moyamoya patients and to determine whether these delays affect the results of brain connectivity mapping.

R Reeve Ingle¹, Holden H. Wu², Nii Okai Addy¹, Jieying Luo¹, Joseph Y. Cheng¹, Phillip C. Yang³, Bob S Hu^1,4, and Dwight G Nishimura^1
1Electrical Engineering, Stanford University, Stanford, California, United States, ²Radiological Sciences, UCLA, California, United States, ³Cardiovascular Medicine, Stanford University, Stanford, California, United States, ⁴Palo Alto Medical Foundation, Palo Alto, California, United States

A nonrigid autofocus motion correction technique is presented for coronary magnetic resonance angiography (CMRA) using a free-breathing 3D cones non-Cartesian sequence. Translational motion measurements from 2D or 3D image navigators are used to derive a set of candidate motion trajectories. A bank of motion-compensated CMRA images is generated using these candidate trajectories, and a focusing metric is used to reconstruct the final image by selecting the best-focused pixels. The proposed technique is shown to improve the depiction of coronary arteries in volunteer and patient studies.