Hyperpolarized 129Xe MR Imaging of Alveolar-Capillary Gas Transfer in Human Volunteers
Zackary I. Cleveland^1,2, Gary P. Cofer^1,2, Gregory Metz³, Denise Beaver³, John Nouls^1,2, Sivaram Kaushik^1,2, Monica Kraft³, Jan Wolber⁴, Kevin T. Kelly⁵, H Page McAdams², Bastiaan Driehuys^1,2
1Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States; ²Radiology, Duke University Medical Center, Durham, NC, United States; ³Pulmonary and Critical Care Medicine, Duke University Medical Center, Durham, NC, United States; ⁴GE Healthcare, Amersham, United Kingdom; ⁵Radiation Oncology, Duke University Medical Center, Durham, NC, United States

We demonstrate single breath-hold, 3D MRI of hyperpolarized 129Xe dissolved in the pulmonary tissues of humans. Dissolved 129Xe produces acceptable image quality because magnetization is efficiently replenished by diffusion from the airspaces. While ventilation images (3.0´3.0&´15 mm3 resolution) of healthy volunteers were generally homogeneous, dissolved 129Xe images (12.5´12.5´15 mm3) displayed higher signal intensities in the gravitationally dependent portions slices. Dissolved 129Xe images of COPD patients were also heterogeneous but displayed different, less directional, patterns. These results suggest that dissolved 129Xe MRI is sensitive to the gravity-dependent distribution of pulmonary perfusion and possibly disease related redistributions of pulmonary capillary blood volume.

Simultaneous Imaging of Ventilation Distribution and Gas Exchange in the Human Lung Using Hyperpolarized Xe129 MRI
John P. Mugler, III¹, Talissa A. Altes¹, Iulian C. Ruset^2,3, Isabel M. Dregely², Jaime F. Mata¹, G. Wilson Miller¹, Stephen Ketel³, Jeffrey Ketel³, F William Hersman^2,3, Kai Ruppert^1
1Radiology, University of Virginia, Charlottesville, VA, United States; ²Physics, University of New Hampshire, Durham, NH, United States; ³Xemed, LLC, Durham, NH, United States

This work demonstrates the feasibility of using MRI of hyperpolarized Xe129 to acquire images in a single, short breath-hold period that simultaneously depict ventilation distribution and gas exchange in the human lung with matched spatial resolution.  The method presents new opportunities for quantifying relationships among gas delivery, exchange and transport, and shows significant potential to provide new insights into lung disease.

Mapping of ³He Apparent Diffusion Coefficient Anisotropy at Sub-Millisecond Diffusion Times in Sham-Instilled and Elastase-Instilled Rat Lungs
Xiaojun Xu^1,2, Juan Parra-Robles³, Alexei Ouriadov¹, Giles E. Santyr^1,4
1Imaging Laboratories, Robarts Research Institute, London, Ontario, Canada; ²Department of Physics, University of Western Ontario, London, Ontario, Canada; ³University of Sheffield, Sheffield, United Kingdom; ⁴Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada

³He diffusion in the lungs is restricted by airway and alveoli walls and therefore is highly dependent on lung microstructure. ³He ADC has been shown to be sensitive to changes in terminal airway anatomy, specifically alveolar damage due to emphysema in both humans and animal models.  At the terminal airway, ³He diffusion has been demonstrated to be anisotropic, described by longitudinal diffusion coefficient (D_L) and transverse diffusion coefficient (D_T). The purpose of this work was to measure and compare D_L and D_T maps in sham-instilled and elastase-instilled Wistar rats at two sub-millisecond (360 μs and 800 μs ).

Evaluation of Emphysema Progression in Chronic Obstructive Pulmonary Disease (Copd); 3He 3D Adc Measurements Compared with Ct and Lung Function Test, Preliminary Results
Frederik Hengstenberg^1,2, Torsten Dorniok¹, Sergei Karpuk³, Jørgen Vestbo², Rahim Rizi⁴, Per Åkeson¹, Peter Magnusson¹, Lise Vejby Søgaard^1
1Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; ²Department of Cardiology and Respiratory Medicine, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; ³Institute of Physics, University of Mainz, Mainz, Germany; ⁴Department of Radiology, University of Pennsylvania, PA, United States

There is a need for developing a more sensitive biomarker for monitoring progression of pulmonary emphysema in COPD.  In this study with 20 COPD patients and 5 healthy control subjects the use of the 3He apparent diffusion coefficient (ADC) in assessing progression was investigated in a one year longitudinal study comparing ADC measurements, CT densitometry and lung function tests. In a subgroup of emphysema patients a significant increase of ADC was detected, reflecting disease progression. 

Functional Lung Imaging of Childhood Asthma Using Radial MRI with Hyperpolarized Noble Gas
Sean Fain¹, Rafael O'Halloran², Eric Peterson³, James Holmes^4
1Medical Physics, University of Wisconsin - Madison, Madison, WI, United States; ²Radiology, Stanford University, Stanford, CA, United States; ³Biomedical Engineering, University of Wisconsin - Madison, Madison, WI, United States; ⁴Applied Science Lab, GE Healthcare, Madison, WI, United States

Assessment of lung function in pediatrics poses significant challenges due to variable ability to cooperate with respiratory maneuvers.  Radial dynamic 3D imaging using multi-echo VIPR (ME-VIPR) acquisition with HP He-3 and I-HYPR reconstruction is used in a protocol designed to minimize breath-hold time for whole lung coverage with good isotropic resolution, and sufficient temporal resolution to adapt to the subject's ability to perform respiratory maneuvers. Diffusion-weighted MRI with HP He-3 MRI also provides a means to assess microstructure of the lung parenchyma without ionizing radiation. Preliminary results in 40 pediatric subjects at-risk for asthma are presented.

Simultaneous Acquisition of 3He Ventilation Images, ADC, T2* and B1 Maps in a Single Scan with Compressed Sensing
Salma Ajraoui¹, Juan Parra-Robles¹, Helen Marshall¹, Martin H. Deppe¹, Steve R. Parnell¹, Jim M. Wild^1
1University of Sheffield, Sheffield, United Kingdom

A novel interleaved sequence is presented in this work that allows acquisition of 3He ventilation, ADC, T2* and B1 maps simultaneously in-vivo. B1 maps were used to corrected the ventilation image for the artifacts due to the B1 inhomogeneities, while Compressed Sensing scheme was used to accelerate the temporal resolution. The sequence was tested in three healthy volunteers and the values of parameters obtained are in accordance with previously published results.

Measurement of Gas Flow and Oxygenation in Small Animal Lungs Using Hyperpolarized Gas
Stephen J. Kadlecek¹, Puttisarn Mongkolwisetwara¹, Kiarash Emami¹, Masaru Ishii², Jianliang Zhu³, Elaine Chia¹, John M. Woodburn¹, Rahim R. Rizi^1
1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States; ²Department of Otolaryngology, Johns Hopkins University, Baltimore, MD, United States; ³Department of Surgery, University of Pennsylvania, Philadelphia, PA, United States

Measurement of pulmonary oxygen concentration in small animals using hyperpolarized gas is shown to be complicated by gas redistribution during the short breath-hold.  This additional complexity can be incorporated into a model which yields information about airway obstruction and is potentially itself of diagnostic value.

Lung MR Imaging with Ultra-Short TE at 3.0T System: Capability for Pulmonary Functional Loss Due to COPD - not available
Yoshiharu Ohno¹, Hisanobu Koyama¹, Keiko Matsumoto¹, Yumiko Onishi¹, Daisuke Takenaka¹, Munebu Nogami¹, Nobukazu Aoyama², Hideaki Kawamitsu², Makoto Obara³, Marc van Cauteren³, Masaya Takahashi⁴, Kazuro Sugimura^1
1Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; ²Radiology, Kobe University Hospital, Kobe, Hyogo, Japan; ³Philips Healthcare, Tokyo, Japan; ⁴Radiology, The University of Texas Southwestern Medical Center, Dallas, TX, United States

Regional T2* measurement can be easier performed by using 3.0 T system than 1.5 T system in routine clinical practice.  We hypothesized that direct T2* measurement in the lung has potential to play a new method for pulmonary functional loss assessment at 3.0 T system.  The purpose of this study was to determine the capability of Lung MR imaging with ultra-short TE (uTE MRI) at 3T MR system for measurement of regional T2* in the lung and pulmonary functional assessment in normal and COPD subjects.

Lung Imaging in the Mouse with SWIFT
Curtis Andrew Corum^1,2, Djaudat Idiyatullin¹, Steen Moeller¹, Ryan Chamberlain¹, Deepali Sachdev^2,3, Michael Garwood^1,2
1Center for Magnetic Resonance Research, Dept. of Radiology, Medical School, University of Minnesota, Minneapolis, MN, United States; ²Masonic Cancer Center, Medical School, University of Minnesota, Minneapolis, MN, United States; ³Department of Medicine, Medical School, University of Minnesota, Minneapolis, MN, United States

Lung and especially lung parenchyma are especially difficult to image with MRI.  T2* times are in the sub-millisecond range and may require specialized hardware and methods to for optimum visualization or quantitative information.  Many lung pathologies such as inflamation (asthma), primary and metastatic neoplasms (cancer) would benefit from more robust and higher SNR methodologies.  SWIFT is a recently developed 3D radial imaging sequence, sensitive to ultra-short T2 and T2* signals.  We demonstrate for the first time, free breathing prospectively gated 1H SWIFT images of the mouse lung.  Lung parenchyma has significant signal and information content while bronchi appear dark.

Dynamic Oxygen-Enhanced MRI in Patients with Pulmonary Arterial Hypertension
Olaf Dietrich¹, Daniel Maxien, Sven Thieme, Maximilian F. Reiser¹, Konstantin Nikolaou
¹Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, LMU Ludwig Maximilian University of Munich, Munich, Germany

Dynamic oxygen-enhanced MRI (O₂-MRI) of the lung was applied in 11 healthy volunteers and in 20 patients with pulmonary arterial hypertension (PAH). Data was evaluated pixelwise by fitting a piecewise exponential model function with 4 parameters (relative enhancement, signal delay, wash-in/out times) to the signal time course. The individual parameter distributions were compared between volunteers and patients. The median values of the determined parameters were similar in both groups, but the ranges (16th to 84th percentile) of relative signal enhancement, signal delay and wash-out time constant were significantly increased in PAH patients.