Marcus J. Couch^1,2, Matthew S. Fox^3,4, Chris Viel^1,2, Gowtham Gajawada^1,2, Tao Li², and Mitchell S. Albert^1,2
1Lakehead University, Thunder Bay, Ontario, Canada, ²Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada, ³Robarts Research Institute, London, Ontario, Canada, ⁴Department of Medical Biophysics, Western University, London, Ontario, Canada

¹⁹F MR imaging was performed in a rat model of pulmonary inflammation using SF₆. Fractional ventilation maps and ventilation gradients were compared between controls and rats that were instilled with lipopolysaccharide. Ventilation gradients calculated from control rats showed the expected gravitational relationship, while ventilation gradients calculated from LPS-instilled rats showed the opposite trend. Inflammation may disrupt the expected gradient in lung compliance, and elevated alveolar wall thicknesses in LPS-instilled rats were confirmed by histology. Overall, ¹⁹F MRI may be able to detect the presence of inflammation using a simple and inexpensive approach that can potentially be translated to humans.

Flavio Carinci^1,2, Cord Meyer², Felix A. Breuer¹, and Peter M. Jakob^1,2
1Research Center Magnetic Resonance Bavaria (MRB), Würzburg, Bayern, Germany, ²Department of Experimental Physics 5, University of Würzburg, Würzburg, Bayern, Germany

Susceptibility differences at air/tissue interfaces in the lung result in a broad NMR spectral line. The line broadening provides a quantitative fingerprint for lung inflation and may be used to diagnose air trapping or ventilation defects. Quantification of the line broadening of the lung has been previously proposed, using an asymmetric spin-echo (ASE) sequence. In this work, a fast technique based on a HASTE sequence with ASE preparation is presented. Quantification of the line broadening of the human lung in-vivo is feasible in a single breath-hold and may be suitable for clinical studies on patients with lung diseases. The results obtained in the lung parenchyma (about 1.5ppm) are in very good agreement with the ones predicted by numerical simulations.

Andrea Bianchi¹, Sandrine Dufort^2,3, Pierre-Yves Fortin^1,4, François Lux⁵, Gerard Raffard¹, Nawal Tassali¹, Olivier Tillement⁵, Jean-Luc Coll², and Yannick Crémillieux^1
1Centre de Résonance Magnétique des Systèmes Biologiques, University of Bordeaux, Bordeaux, Bordeaux, France, ²IAB-INSERM U823, University Joseph Fourier, Grenoble, France, ³Nano-H, Saint Quentin – Fallavier, France, ⁴Institut de Bio-Imagerie (IBIO) CNRS/UMS 3428, University of Bordeaux, Bordeaux, France, ⁵ILM UMR 5306, University Lyon 1, Lyon, France

Lung cancer is the leading cause of cancer deaths worldwide. MRI can play a major role being a noninvasive imaging technique, characterized by good soft tissue contrast, high spatial resolution, and absence of ionizing radiation. We propose here an in vivo MRI longitudinal study of lung adenocarcinoma detection in tumor-bearing immunodeficient mice without the use of contrast agents. Free-breathing Ultra-short Echo Time (UTE) MRI acquisitions were compared to standard gradient echo lung MR images using both respiratory-gated and free-breathing protocols. The results were validated against Bioluminescence Imaging (BLI) and histology.

Yoshiharu Ohno^1,2, Shinichiro Seki³, Hisanobu Koyama³, Aiming Lu⁴, Masao Yui⁵, Mitsue Miyazaki⁴, Katsusuke Kyotani⁶, Yoshiko Ueno³, Takeshi Yoshikawa^1,2, Sumiaki Matsumoto^1,2, and Kazuro Sugimura^3
1Advanced Biomedical Imaging Research, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan, ²Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan, ³Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan, ⁴Toshiba Medical Research Institute USA, IL, United States, ⁵Toshiba Medical Systems Corporation, Tochigi, Japan, ⁶Center for Radiology and Radiation Oncology, Kobe University Hospital, KObe, Hyogo, Japan

Pulmonary 3D MR imaging with ultra-short TE (UTE-MRI) has been suggested as having the potential for demonstration of lung structures and functions. However, to the best of our knowledge, no direct comparison of capability for radiological finding assessment has been made between UTE-MRI at 3T system and thin-section CT (TS-CT) in patients with various pulmonary diseases. We hypothesized that UTE-MRI has a potential to evaluate radiological findings as well as TS-CT. The purpose of this study was directly compare the capability of UTE-MRI for evaluation of radiological findings with TS-CT in patients with various pulmonary diseases.

Åsmund Kjørstad¹, Marta Tibiletti², Andrea Bianchi³, Michael Neumaier³, Andrea Vögtle³, Thomas Kaulisch³, Frank G. Zöllner¹, Lothar R. Schad¹, Volker Rasche², and Detlef Stiller^3
1Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany, ²Core Facility Small Animal MRI, Ulm University, Ulm, Germany, ³Target Discovery Research, In-vivo imaging laboratory, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany

Using the 1H MRI signal difference in the lung parenchyma at inspiration and expiration during normal breathing is a promising method for assessing lung function. However, due to the difficulties of self-gating in rodents no animal studies have so far been performed using this method. For the first time we demonstrate here the feasibility of the method in small animals by evaluating the lung function in rats with emphysema using a self-gating golden angle 2D UTE sequence and a thorax-optimized phased-array coil.

Magdalena Zurek¹, Louise Sladen², Edvin Johansson¹, Sonya Jackson³, Gaell Mayer³, and Paul D Hockings^2
1PHB, Imaging, AstraZeneca R&D, Mölndal, Sweden, ²Drug Safety and Metabolism, AstraZeneca R&D, Mölndal, Sweden, ³RIA, Bioscience, AstraZeneca R&D, Mölndal, Sweden

An oxygen-enhanced MRI protocol that permits quantification of spatially matched ventilation and oxygen uptake was implemented and applied to assess the relationships between lung parenchyma density, oxygen delivery and uptake in a mouse model of elastase-induced lung emphysema. All parameters could be derived based on parameters obtained from an inversion-recovery experiment. Although no differences in global enhancement were detected between the groups, pixel-level analysis revealed differences between control and treated mice that depended on tissue density (damage). Significantly, treated animals showed larger variations in oxygen uptake suggesting the ability of the lung’s functional reserve to compensate for the non-performing regions.

Dante Capaldi^1,2, Nanxi Zha¹, Damien Pike^1,2, Khadija Sheikh^1,2, David G McCormack³, and Grace Parraga^1,2
1Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada, ²Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada, ³Division of Respirology, Department of Medicine, The University of Western Ontario, London, Ontario, Canada

We compared hyperpolarized MRI ventilation and CT-derived parametric-response-mapping (PRM) measurements – surrogate measurements of small airways disease, in 40 COPD patients. In mild COPD, there were fewer, smaller ventilation defects, negligible category II (small airways disease) and no category III voxels (emphysema). Severe COPD was reflected by a greater number and volume of ventilation defects and a greater number of category III (emphysema) voxels. MRI VDP was significantly correlated with category II CT voxels in mild but not moderate-severe COPD supporting the use of CT-derived PRM measurements of gas trapping related to small airway remodeling in mild but not moderate-severe COPD.

Rohan S Virgincar¹, Scott H Robertson², Simone Degan^3,4, Matthew S Freeman², Mu He⁵, and Bastiaan Driehuys^4
1Biomedical Engineering, Duke University, Durham, North Carolina, United States, ²Medical Physics Graduate Program, Duke University, Durham, North Carolina, United States, ³Center for Molecular and Biomolecular Imaging, Duke University, Durham, North Carolina, United States, ⁴Radiology, Duke University Medical Center, Durham, North Carolina, United States, ⁵Electrical and Computer Engineering, Duke University, Durham, North Carolina, United States

We present high-resolution and high-SNR isotropic ¹²⁹Xe gas- and dissolved-phase MR imaging in mice to study lung cancer progression longitudinally. This was enabled by an optimized 3D radial image acquisition with 20% ¹²⁹Xe polarization. Animals were scanned up to 3 times before being sacrificed for histology. ¹²⁹Xe images showed significant impairment of ventilation and gas-exchange 4-6 weeks post tumor instillation that closely matched tumor distribution on ¹H MRI. This non-invasive imaging capability is now well suited to study the progression of a variety of lung disorders and therapy response.

Wei Zha¹, Stanley J Kruger¹, Robert V Cadman¹, David Mummy², David J Niles¹, Scott K Nagle^1,3, and Sean B Fain^1,3
1Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States, ²Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, United States, ³Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States

A recent study proposed K-means-based defect segmentation (“Kirby method”) and evaluated its performance on 15 subjects. In our study, 83 asthma and 8 cystic fibrosis subjects underwent spirometry and hyperpolarized helium-3 MRI. The percent ventilation defect (%VD) was determined using manual segmentation and semi-automatically with the Kirby method and an improved adaptive K-means approach. The adaptive K-means approach corrected for B1 inhomogeneity, excluded pulmonary vasculature and determined defects adaptively. The %VD measured using either manual segmentation or this improved K-means-based approach was correlated with the spirometric measures, whereas correlation was not observed with the Kirby method.

Neil James Stewart¹, Graham Norquay¹, Paul David Griffiths¹, and Jim Michael Wild^1
1Academic Unit of Radiology, University of Sheffield, Sheffield, South Yorkshire, United Kingdom

Diagnostic quality lung ventilation imaging with naturally-abundant hyperpolarized xenon gas has been demonstrated in healthy normal subjects and a healthy smoker at 1.5 T and 3 T for the first time. A 3D steady-state free precession sequence was optimized for maximal ¹²⁹Xe image SNR via numerical simulations. SNRs of 25 - 40 were routinely achieved for a voxel size 4.2 x 4.2 x 8/10 mm³, with ~ 30% improvement at 3 T versus 1.5 T. Image quality was comparable to that obtained with 400 mL enriched xenon and 200 mL ³He, and was sufficient for identification of minor ventilation defects.