|Lung Structure & Function|
Young Investigator Award Finalist: Hyperpolarized 3He
Diffusion MRI at Two Time Scales During a Single Breath Hold: Assessment
of the Lung Microstructure in Asthmatics with Comparison to Healthy and
Chengbo Wang1, Talissa A. Altes1, 2, John P. Mugler, III2, G. Wilson Miller2, Kai Ruppert1, 2, Jaime F. Mata2, Gordon D. Cates, Jr2, Larry Borish2, Eduard E. de Lange2
1Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 2University of Virginia, Charlottesville, Virginia , USA
Co-registered short-time-scale and long-time-scale hyperpolarized 3He ADC maps were collected in 14 healthy, 14 asthma and 9 COPD subjects. Compared to the healthy group, the short-time-scale and long-time-scale mean ADC was increased by 9% and 27% (p=0.038 and 0.005) in asthmatics, respectively, and 71% and 117% (p=0.002 and p<0.001) in subjects with COPD, respectively. Regional changes on long-time-scale ADC maps were more conspicuous and more extensive than on short-time-scale ADC maps. Thus, diffusion abnormalities are present in asthmatics, and the long-time-scale ADC appears to have an increased regional sensitivity to these abnormalities.
In Vivo Lung Morphometry Identifies Detail
Changes of Lung Microstructure with Emphysema Progression
Dmitriy A. Yablonskiy1, Alex L. Sukstanskii1, Jason C. Woods, Andrew J. Bierhals1, Yulin V. Chang, Richard E. Jacob, Mark S. Conradi, David S. Gierada1
1Mallinckrodt Institute of Radiology, St. Louis, Missouri, USA
Numerous measurements of hyperpolarized 3He gas ADC in human lungs indicated substantial changes between healthy and emphysematous lungs. Herein we use the in vivo lung morphometry technique, based on MRI measurement of diffusion of hyperpolarized 3He gas, to identify changes in lung microstructure with emphysema progression. We demonstrate that at the initial stages of emphysema, walls separating alveoli belonging to the same acinar airways are getting destroyed by the disease without substantial effect on inter-airway walls. This follows by destruction of inter-airway walls. We conclude that the In vivo lung morphometry allows non-invasive monitoring emphysema progression at the alveolar level.
|16:32||395.||Self-Calibrated Voxel-Wise Assessment of
Ventilation During Respiration Using Dynamic Hyperpolarized 3He MRI
Davide Santoro1, Abram Voorhees2, Vinay Pai1, Igor Kamenetskiy1, Jean Reid1, Glyn Johnson1
1New York University School of Medicine, New York, USA; 2Siemens Medical Solutions, Inc., Malvern, USA
In this work, a novel method for tracking regional lung motion is applied to provide the local air volume and volumetric flow rate on a voxel scale. The method is based on motion-tracking of the lungs over a series of real-time, hyperpolarized 3He images.
Determination of Alveolar Oxygen Partial Pressure in Rat
Lung Using Spin-Spin Relaxation Times of 3He and 129Xe at Low Magnetic
Ryan Kraayvanger1, 2, Chris Bidinosti3, William Dominguez-Viqueria1, 2, Juan Parra-Robles2, Matthew Fox1, 2, Wilfred Lam2, Giles Santyr, 12
1University of Western Ontario, London, Canada; 2Robarts Research Institute, London, Canada; 3University of Winnipeg, Winnipeg, Canada
Quantitative assessment of alveolar oxygen partial pressure (pAO2) in the lung has the potential to become a remarkably useful tool in the diagnosis and monitoring of respiratory disease. It has been demonstrated that pAO2 can be measured using the spin-spin relaxation time, T2, of 3He at very low magnetic field strengths with the Carr-Purcell-Meiboom-Gill (CPMG) sequence. We present relaxivity relationships for oxygen’s effect on 3He and 129Xe spin-spin relaxation, in vivo T2 measurements in rat lung, and test the assertion that T2=T1 in the limit of rapid CPMG pulse rates at low magnetic field strength.
Detection of Perfusion-Induced Susceptibility Effect
in the Lung by Hyperpolarized 3He MRI: A Co-Registration with Partial
Pressure of Oxygen
Jiangsheng Yu1, Michelle Law1, Kiarash Emami1, Sheeva Rajaei1, Masaru Ishii, 12, Stephen Kadlecek1, Vahid Vadhat1, John MacDuffie Woodburn1, Richard A. Guyer1, Hans Hyonchang Kim1, Warren Gefter1, Rahim R. Rizi1
1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Johns Hopkins University, Baltimore, Maryland, USA
Hyperpolarized 3He MRI has focused primarily on structural and functional aspects of the airspaces. In this work, we present a double-echo acquisition technique for measuring perfusion-induced susceptibility effect. This technique allows automatic co-registration of lung perfusion and ventilation images. In the in-vivo animal experiment, a normal Yorkshire pig (~20kg) was injected with 10mL gadolinium to modify the magnetic susceptibility difference between the lung airway and capillary bed. A susceptibility measurement was performed 10 minutes after the Gd injection. The average phase change caused by this susceptibility difference enhancement (Gd injection) was 57 degrees; while the global mean values of pO2 and R were not affected by the Gd injection.
Quantitative Analysis of MCh Induced Ventilation
Changes in Mouse Lungs in a Time Series
Nilesh Navnitlal Mistry1, 2, Bastiaan Driehuys2, Boma Fubara2, William M. Foster2, Erin N. Potts2, Ben Chen3, Deborah M. Slipetz3, G. Allan Johnson2
1Duke University, Durham, North Carolina, USA; 2Duke University Medical Center, Durham, North Carolina, USA; 3Merck Frosst Center for Therapeutic Research, Montreal, Canada
Recent high-resolution 3He MRI in mouse models of asthma have provided an opportunity to understand airway biology by depicting regional ventilation changes, and airway narrowing and closure. To maximize the value of 3He MRI, it is important to quantify these ventilation changes visible in the images. In this work, we describe a post-processing scheme to quantify regional ventilation changes before and after MCh challenge; and show that it is sensitive to both changes in airway caliber and subtle regional alterations in ventilation.
ENaC-Mediated Effects Assessed by Proton
MRI in a Rat Model of Hypertonic Saline-Induced Hydration of Airways
François-Xavier Blé1, 2, Stefan Zurbruegg1, Steve Collingwood3, Henry Danahay3, Nicolau Beckmann1
1Novartis Institutes for BioMedical Research, Basel, Switzerland; 2University Louis Pasteur-Strasbourg-1, Illkirch, France; 3Novartis Institutes for BioMedical Research, Horsham, UK
Nebulized hypertonic saline (HS) provides benefit to cystic fibrosis patients. Since the effects of HS are transient, administration of epithelial sodium channel (ENaC) blockers prior to HS is being pursued as strategy to improve the duration of action of HS. Using MRI we followed the fluid dynamics in the lungs of spontaneously breathing rats treated with compounds that interacted with ENaC, administered before HS. As a non-invasive readout of global fluid dynamics in the whole lung in situ, MRI provides complementary information to that obtained using in vitro or ex vivo models currently supporting ENaC-related drug investigations.
Multi-Center Study for Clinical Stage Classification
of Smoking-Related COPD: Oxygen-Enhanced MRI vs. Quantitatively Assessed
Yoshiharu Ohno1, Tae Iwasawa2, Joom Beom Seo3, Hisanobu Koyama1, Hiroshi Takahashi2, Yeon-Mok Oh3, Yoshihiro Nishimura4, Kazuro Sugimura1
1Kobe University Graduate School of Medicine, Kobe, Japan; 2Kanagawa Cardiovascular and Respiratory Center, Yokohama, Japan; 3University of Ulsan College of Medicine, Seoul, Republic of Korea; 4Kobe University Graduate School of Mediciine, Kobe, Japan
O2-enhanced MRI as well as hyperpolarized noble gas MR imaging have been proposed as useful procedures for evaluation of morphological changes or regional pulmonary functional changes. However, the literature shows no publications dealing with prospective and direct comparison of the capability of quantitatively assessed CT (quantitative CT) and of O2-enhanced MRI for smoking-related functional loss assessment and clinical stage classification of smoking-related COPD. The purpose of the multi-center trial conducted for this purpose was to prospectively and directly compare the efficacy of O2-enhanced MRI and quantitative CT for smoking-related pulmonary functional loss assessment and clinical stage classification of smoking-related COPD.
Increased Pulmonary Capillary Permeability in Smokers
as Measured by DCE-MRI
Josephine Helen Naish1, Deirdre M. McGrath1, Charles E. Hutchinson1, Lars E. Olsson2, John C. Waterton, 13, Chris J. Taylor1, Geoff J. Parker1
1University of Manchester, Manchester, UK; 2AstraZeneca, Mölndal, Sweden; 3AstraZeneca, Macclesfield, UK
In this study we demonstrate the feasibility of measuring regional pulmonary vascular endothelial permeability using DCE-MRI. By acquiring and modelling an extended dynamic time series we observe significantly increased vascular permeability in a group of smokers compared with a group of non-smokers. This observation is consistent with the presence of smoking-induced inflammation.