TRADITIONAL POSTER - ismrm

2540. Exact Results for Diffusion Weighted MR on Branched Structures
Niels Buhl 1,2 , Sune Jespersen 2
1 Physics and Astronomy, University of Aarhus, Aarhus, Denmark; 2 CFIN, University of Aarhus, Aarhus, Denmark
Poster Sessions
Diffusion-weighted MRI (DWI) employing long diffusion times can provide information on connectivity and topology in branching systems. We present an
exact result for the diffusion propagator on a large class of metric networks (graphs), and subsequently derive an analytical expression for the signal
attenuation in a PGSE diffusion experiment. We apply these results to a simple acinar model and demonstrate the sensitivity of DWI to an increasing number
of collateral pathways.
2541. Long-Time-Scale Hyperpolarized 3 He and 129 Xe Diffusion in Human Lungs: Experimental
Measurements and Computer Simulation
Chengbo Wang 1 , Talissa A. Altes 1 , John P. Mugler, III 1,2 , Eduard E. de Lange 1 , Kai Ruppert 1 , William F.
Hersman 3,4 , Isabel M. Dregely 3 , Iulian Ruset, 3,4 , Stephen Ketel 4 , Sylvia Verbanck 5
1 Radiology, University of Virginia, Charlottesville, VA, United States; 2 Biomedical Engineering, University of Virginia,
Charlottesville, VA, United States; 3 Physics, University of New Hampshire, Durham, NH, United States; 4 Xemed LLC, Durham, NH,
United States; 5 Respiratory Division, University Hospital UZ Brussel, Brussels, Belgium
Long-time-scale 3He and 129Xe diffusion was measured in human lungs and was found to strongly depend on the diffusion times. The computer simulation
agreed well with experimental measurements using only the intra-acinar structure, suggesting that long-time-scale ADC was dominated by intra-acinar
structure in the lung. The importance of the intra-acinar structure and collateral channels may vary with varying parameters such as tag wavelength. Intraand
interacinar collateral channels can lead to considerable relative ADC increases, suggesting that noble gas diffusion may be sensitive to mild degree of
collateral channels which may occur in early smoking related lung disease.
2542. Imaging Morphometric Changes in the Human Pulmonary Acinus in Vivo Via 3 He Diffusion MRI
Adam J. Hajari 1,2 , James D. Quirk 2 , Dmitriy A. Yablonskiy, 12 , Alex L. Sukstanskii 2 , Mark S. Conradi 1,2 ,
Jason C. Woods, 12
1 Physics, Washington University, St. Louis, MO, United States; 2 Radiology, Washington University, St. Louis, MO, United States
3 He diffusion MRI is used to study in-vivo morphological changes at the alveolar level in human lungs. We employ a 6 b-value diffusion pulse sequence for
imaging at three different levels of inspiration. An established mathematical model relating signal attenuation from the diffusion gradients to alveolar
geometry is fit voxel-by-voxel to the diffusion images to determine average alveolar depth and alveolar duct radii at each of the three lung volumes. On
average a 50% increase in lung volume led to a 9% increase in average alveolar duct radius and a 22% decrease in average alveolar depth.
2543. Measurement of the Diffusion of Hyperpolarized 129 Xe in Human Lungs Over Short and Long Time
Scales During One Breath Hold
Chengbo Wang 1 , John P. Mugler, III 1,2 , Eduard E. de Lange 1 , Kai Ruppert 1 , William F. Hersman 3,4 , Isabel
M. Dregely 3 , Iulian Ruset, 3,4 , Stephen Ketel 4 , Talissa A. Altes 1
1 Radiology, University of Virginia, Charlottesville, VA, United States; 2 Biomedical Engineering, University of Virginia,
Charlottesville, VA, United States; 3 Physics, University of New Hampshire, Durham, NH, United States; 4 Xemed LLC, Durham, NH,
United States
Regional ADC maps of hyperpolarized 129Xe in human lungs measured over both short and long time scales and with identical spatial registration during a
single breath hold were acquired in 5 human subjects. Measured 129Xe ADC values were about 10% of the corresponding previously reported 3He ADC
values for both time scales, similar to the expected difference of 16% due to the differences in diffusivity of the gases. The current SNR of 129Xe MRI is
sufficient for diffusion MRI, and 129Xe diffusion MRI has been performed in healthy subjects and subjects with lung disease.
2544. Relationship Between Lung Function and Lung Structure in Smokers as Measured by Hyperpolarized
Helium-3 MRI
Chengbo Wang 1 , Talissa A. Altes 1 , John P. Mugler, III 1,2 , Eduard E. de Lange 1 , Robert M. Strieter 3 , Yun M.
Shim 3,4
1 Radiology, University of Virginia, Charlottesville, VA, United States; 2 Biomedical Engineering, University of Virginia,
Charlottesville, VA, United States; 3 Medicine, University of Virginia, Charlottesville, VA, United States; 4 Pulmonary and Critical
Care, University of Virginia, Charlottesville, VA, United States
Short-time-scale (STS) and long-time-scale (LTS) helium-3 ADC values were measured in the lungs of smokers and found to be moderately correlated with
%predFEV1, but poorly correlated with exercise stress testing, possibly because non-respiratory factors may significantly affect exercise capacity. STS
helium-3 ADC values did not correlate with %DLCO while LTS ADC values were moderately correlated with %DLCO. These results support an association
between lung microstructural alterations caused by cigarette smoking and functional changes in FEV1 and %DLCO, and suggest that LTS ADC is more
sensitive than STS ADC in detecting early pulmonary injury.
2545. Hyperpolarized 129 Xe Diffusion MRI of the Lungs in Healthy Subjects and Chronic Obstructive
Pulmonary Disease Patients
Suryanarayanan Sivaram Kaushik 1 , Zackary I. Cleveland 1 , Gary P. Cofer 1 , Gregory Metz 2 , Denise
Beaver 2 , John Nouls 1 , Monica Kraft 3 , Jan Wolber 4 , H Page McAdams 2 , Bastiaan Driehuys 1
1 Center for In-Vivo Microscopy, Duke University Medical Center, Durham, NC, United States; 2 Radiology, Duke University Medical
Center, Durham, NC, United States; 3 Pulmonary and Critical Care Medicine, Duke University Medical Center, Durham, NC, United
States; 4 GE Healthcare, Amersham, United Kingdom
Apparent diffusion coefficient (ADC) MRI using hyperpolarized 3He has been established as a radiation free alternative to Computerized Tomography in
evaluating pulmonary microstructure, but its use is limited in biomedical research applications due to its high cost and low availability. Recently, the success