Session WOB. There are 6 abstracts in this session.



Session: Hyperpolarization 1, time: 08:30am-08:50am

A Variable Resolution Echo-Planar Imaging Approach for Improved Quantification of Hyperpolarized 13C Metabolism


Jeremy Gordon; Eugene Milshteyn; Robert Bok; Daniel B Vigneron; Peder E. Z. Larson
University of California, San Francisco, CA
Unlike ionizing imaging modalities, the SNR in MRI is proportional to voxel volume, but downsampling or voxel averaging after acquisition only improves SNR by the square root of the voxel volume. To take advantage of this distinction, we use a frequency selective imaging approach to independently excite the hyperpolarized 13C substrate (pyruvate) and downstream metabolites (lactate, alanine, and bicarbonate), allowing us to tailor the spatial resolution for each metabolic product. We show the advantage of this approach in a pre-clinical study of [1-13C]pyruvate metabolism in healthy rat kidneys and in a healthy human volunteer study of cerebral metabolism.

Session: Hyperpolarization 1, time: 08:50am-09:10am

Development of Computational Methods for B1-Corrected Hyperpolarized C-13 MRI Human Studies


Philip Lee1, 2; Hsin-Yu Chen2; Jeremy Gordon2; Peder Larson1, 2; Mark Van Criekinge2; Michael Ohliger2; Duan Xu1, 2; John Kurhanewicz1, 2; Robert Bok2; Pamela Munster3; Daniel Vigneron1, 2
1UCB/UCSF Bioengineering Graduate Group, San Francisco, CA; 2UCSF Departments of Radiology & Biomedical Imaging, San Francisco, CA; 3UCSF Department of Medicine, San Francisco, CA
Hyperpolarized 13C MR spectroscopy allows for quantitative monitoring of metabolites, such as pyruvate and lactate, in tissues. However, 13C transmit/receive coils do not have a homogeneous B1 excitation profile, resulting in a decreasing gradient of flip angles for voxels farther away. In this study, the coil’s excitation profile was used to compute the actual flip angle in each voxel, allowing for a more accurate quantification of the pyruvate to lactate conversion rate (kPL) per voxel. Voxels closer to the coil received a higher flip angle than intended. The findings agree with simulations where over-flip leads to an underestimation of kPL, whereas under-flip leads to overestimation. The correction methods developed in this study can improve quantification of metabolism in human cancer.

Session: Hyperpolarization 1, time: 09:10-09:30

Regional Cardiopulmonary Dynamics with Hyperpolarized 129Xe and Radial Keyhole Image Reconstruction


Peter Niedbalski; Matthew Willmering; Laura L. Walkup; Jason Woods; Zackary Cleveland
Cincinnati Children's Hospital Medical Center, Cincinnati, OH
It difficult to quantify the dynamics of complex systems using hyperpolarized (HP) nuclei, because longitudinal magnetization decay varies heterogeneously due to RF and T1. However, magnetization loss can be quantified regionally, without additional measurements, using radial MRI and keyhole reconstruction. Here we extend 3D radial keyhole to measure regional magnetization decay during HP 129Xe imaging and use these measurements to improve the quantification of pulmonary ventilation, and thus disease severity, in cystic fibrosis patients. Further we apply the approach to image HP 129Xe dissolved in the pulmonary capillary bed. Doing so makes it possible to measure regional cardiogenic oscillations within the capillaries, a phenomenon expected to be sensitive to disease state in fatal disorders, including lung fibrosis and pulmonary hypertension.

Session: Hyperpolarization 1, time: 09:30-09:50

Xenon-129 Hyperpolarised MRI Using A Open Design, Upright,  Clinical Scanner


James Harkin; Robert K. Irwin; Shahideh Safavi; Brett Haywood; Andrew Peters; Ian Hall; Michael J. Barlow
University Of Nottingham, Nottingham, United Kingdom
Using a multinuclear 0.5T Paramed Medical Systems MROpen Upright MRI scanner and  a 129Xe surface coil, Xenon images were obtained and dissolved phase signals acquired in multiple media.  We will present preliminary data of volunteers in both supine and upright positions; highlighting the importance of orientation on lung function.  Hyperpolarised MRI has the potential to revolutionise how chronic respiratory diseases are both diagnosed and monitored. The upright and open design of the scanner makes imaging more comfortable for patients and allows for imaging in later stages of respiratory diseases.  The orientational information highlights the effects of gravity on lung function and mechanics.

Session: Hyperpolarization 1, time: 09:50am-10:10am

First Hyperpolarized [2-13C]Pyruvate NMR Studies of Human Brain Metabolism


Brian T Chung1, 2; Hsin-Yu Chen1; Jeremy Gordon1; Daniele Mammoli1; Renuka Sriram1; Adam Autry1; Lydia Le Page1; Myriam Chaumeil1, 3; Peter Shin1; James Slater1; C.T. Tan4; Chris Suszczynski4; Susan Chang5; Robert Bok1; Sabrina Ronen1, 2; Peder E. Z. Larson1, 2; John Kurhanewicz1, 2; Daniel B Vigneron1, 2
1UCSF Dept of Radiology and Biomedical Imaging, San Francisco, CA; 2UCSF-UCB Graduate Program in Bioengineering, San Francisco, CA; 3UCSF Department of Physical Therapy, San Francisco, CA; 4ISOTEC/MilliporeSigma, Miamisburg, OH; 5UCSF School of Medicine, San Francisco, CA
The goal of this study was to develop methods for the hyperpolarization (HP) and preparation of sterile [2-13C]pyruvate with FDA-IND and IRB approval for first-ever human studies.  We sought to investigate HP [2-13C]pyruvate conversion to [2-13C]lactate and [5-13C]glutamate in the healthy brain in four human volunteers.  Using a 32-channel 13C-headcoil, NMR was acquired following the injection of HP [2-13C]pyruvate, and we were able to detect the dynamic conversion of HP [2-13C]pyruvate to [2-13C]lactate, [5-13C]glutamate and other compounds in the normal brain, demonstrating a significant advance for HP metabolic imaging to diagnose and detect early stage neurodisorders.
 

Session: Hyperpolarization 1, time: 10:10-10:30

Choose Your Own Adventure: Hyperpolarized 129Xe MRI Techniques for Imaging Pediatric Lung Disease


Laura L. Walkup1; Matthew M. Willmering1; Abdullah Bdaiwi1, 2; Christopher Towe1, 3; Zackary I. Cleveland1, 3; Jason C. Woods1, 3
1Cincinnati Children's Hospital Medical Center, Cincinnati, OH; 2Biomedical Engineering, University of Cincinnati, Cincinnati, OH; 3Pediatrics, University of Cincinnati, Cincinnati, OH
Pediatric lung disease can be challenging to assess due to poor patient compliance and poor sensitivity of clinical measures of early disease.  As a non-invasive, ionizing-radiation free modality, hyperpolarized 129Xe MRI offers an alternative to quantify regional lung disease.  Recent translational applications of 129Xe MRI in pediatrics will be discussed.  129Xe ventilation MRI is sensitive to ventilation deficits including in children unable to perform spirometry, and 129Xe restricted-diffusion MRI can quantify alveolar-airspace size without an invasive biopsy. Further, we use gas-exchange 129Xe MRI to assess regional interstitial-barrier thickening and perfusion deficits for the first time in pediatrics.  Due to these unique capabilities, 129Xe gas is a powerhouse contrast agent for pulmonary MRI across a diverse pathophysiological spectrum of lung disease.