Andre M. J. Sprengers¹, Matthan W.A. Caan¹, Aart J. Nederveen¹, Jaap Stoker¹, and Rolf M. Lamerichs^2
1Radiology, Academic Medical Centre, Amsterdam, Netherlands, ²Research, Philips, Eindhoven, Netherlands

This study presents the use of continuously tagged imaging for detailed motion assessment in the entire abdomen during free breathing. MRI in the abdominal area is hampered by low tissue contrast and abundant presence of motion artifacts. Motion suppression is never 100% effective and increases the burden of the protocol. The continuously tagged method provides high spatiotemporal resolution information of the unconstrained motion in the abdomen suitable for both motion correction and diagnostic purposes i.e. motility assessment.

Andre M. J. Sprengers¹, Marije P. van der Paardt¹, Frank Zijta¹, Matthan W.A. Caan¹, Rolf M. Lamerichs^1,2, Aart J. Nederveen¹, and Jaap Stoker^1
1Radiology, Academic Medical Centre, Amsterdam, Netherlands, ²Research, Philips, Eindhoven, Netherlands

Synopsis: This study presents the use of continuously tagged imaging for assessment of bowel motility. The tagging prepulse induces stripe patterns in MR images from which motion information can be extracted if the pattern is deformed by tissue motion. However, tagging was developed for cardiac (periodic motion) and the required determination of the patterns can easily lead to high workloads, a common problem in motility assessment methods. This study presents continuously tagged MR acquisition as a fast, non-invasive method for motility assessment over the entire abdominal area including automated post processing.

John Butler¹, Jodi Miller^1,2, Harry Marshall^1,2, Ally Silavi¹, John Patrick^1,2, William Pavlosky³, Gregor Reid^1,4, Don Taves³, Jamie Gregor⁵, Khaleel Sultan⁵, Deanna Carlsen⁶, Artem Khlebnikov⁶, Denis Guyonnet⁷, Sophie Legrain-Raspaud⁷, Frank S Prato^1,2, R Terry Thompson^1,2, and Robert Z Stodilka^1,2
1Lawson Health Research Institute, London, Ontario, Canada, ²Medical Biophysics, University of Western Ontario, London, Ontario, Canada, ³Nuclear Medicine, St. Joseph's Hospital, London, Ontario, Canada, ⁴Microbiology, University of Western Ontario, London, Ontario, Canada, ⁵Gastroenterology, London Health Sciences Center, London, Ontario, Canada, ⁶The Dannon Company, White Plains, New York, United States, ⁷Danone Research, Palaiseau, Cedex, France

This study uses a single-shot MRI technique to provide a 3D dataset for semi-automatic image segmentation to determine large bowel gas volume. An axial interleaved single shot HASTE breath-hold sequence, acquired in isocenter mode at three table positions was used. Three sets of images were acquired in five subjects on a restricted diet, over a day for two consecutive days. Prior to the last two scans on the 2nd day the subjects were given a lactulose challenge. The total gas volume in the large bowel was calculated using an operator interactive segmentation routine to extract the voxels containing gas. The measured gas volumes were consisted in the same subject in Day 1 and 2, but there was larger inter subject variability in the gas volumes. The lactulose did not have a significant effect on gas volumes.

Conor Meehan¹, Saeed Mirsadraee^1,2, and Paul Finn^1
1Department of Radiological Sciences, University of California Los Angeles, Los Angeles, California, United States, ²Clinical Research Imaging Centre, University of Edinburgh, Edinburgh, United Kingdom

This study evaluates the feasibility of 3.0T MR angiography in evaluation of pre-transplant perdiatric patients. Accuracy of the technique in the evaluation of vascular structures is discussed.

Katrien Vandoorne¹, Tegest Aychek², Hagit Dafni¹, Brian A. Hemmings³, Steffen Jung², and Michal Neeman^1
1Biological Regulation, Weizmann Institute, Rehovot, Israel, ²Immunology, Weizmann Institute, Rehovot, Israel, ³Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland

The etiology of inflammatory bowel disease (IBD), a group of inflammatory conditions of the intestinal tract, remains largely unknown. Akt1, a protein kinase, is a major mediator of angiogenic signaling, acting downstream of vascular endothelial growth factor (VEGF). In this study, we reported significantly decreased permeability (PS) in Akt1 deficient mice using macromolecular DCE-MRI, validated by histology. This decreased permeability of albumine-based contrast agent implies less leakage of plasma proteins and thus, limited disease progression. These results provide direct evidence that Akt1 enhances DSS-induced colitis. MRI proved to provide high sensitivity for in vivo detection of reduced permeability in colitis.

Suryanarayanan Sivaram Kaushik^1,2, Gary P Cofer², Matthew S Freeman^2,3, Zackary I Cleveland², and Bastiaan Driehuys^2
1Biomedical Engineering, Duke University, Durham, NC, United States, ²Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States, ³Medical Physics, Duke University Medical Center, Durham, NC, United States

The ~200 ppm chemical shift difference between gaseous hyperpolarized (HP) 129Xe and HP 129Xe dissolved in the lung tissues (dissolved phase) makes this agent an excellent probe of pulmonary gas exchange processes. Dissolved phase HP 129Xe images have displayed profound evidence of gravity-dependent gas exchange heterogeneity. However, a deeper understanding of lung function, and quantitative analysis of ventilation and gas exchange would benefit from simultaneous imaging of 129Xe in the dissolved and gas-phases. In this work, we demonstrate a method to acquire both the gas and dissolved phase images of 129Xe in a single acquisition, using an interleaved 3D-radial sequence.

John Nouls^1,2, Zackary i Cleveland^1,2, Matthew S Freeman³, Harald E. Moeller⁴, Laurence W Hedlund^1,2, and Bastiaan Driehuys^1,2
1Department of Radiology, Duke University, Durham, NC, United States, ²Center for in vivo Microscopy, Duke University, Durham, NC, United States, ³Medical Physics, Duke University, ⁴Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

We demonstrate that acquiring isotropic, 3D images of the ^{129<\sup>Xe distribution in the rat brain is feasible. The images are obtained by simple inhalation delivery within 5 min. However, the intensity in these images display significant heterogeneity. The presence of this heterogeneity, which was not reported in earlier 2D imaging studies, suggests that the distribution of 129<\sup>Xe in the brain is sensitive to a variety of physiologically and anatomically important factors including perfusion, tissue type, and tissue chemistry.}

Hirohiko Imai¹, Atsuomi Kimura¹, Satoshi Iguchi¹, and Hideaki Fujiwara^1
1Department of Medical Physics and Engineering, Division of Health Sciences, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan

We investigated the feasibility of quantitative assessment of emphysema with a combination of gas-phase (GP) and dissolved-phase (DP) hyperpolarized (HP) ¹²⁹Xe lung MRI in spontaneously breathing mice. GP and DP ¹²⁹Xe were imaged by using ultrashort TE (UTE) sequence. By using these images, the fraction F, which is the ratio of the magnetization of ¹²⁹Xe diffused into septa within 50 ms relative to that of the gas space, was regionally evaluated. The F value was significantly reduced in elastase-induced emphysema model, reflecting the alveolar tissue destruction and the value showed significant correlation with histologically derived surface-to-volume ratio (S/V).

Marcus John Couch^1,2, Alexei V Ouriadov¹, and Giles E Santyr^1,3
1Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, ON, Canada, ²Department of Physics and Astronomy, The University of Western Ontario, London, ON, Canada, ³Department of Medical Biophysics, The University of Western Ontario, London, ON, Canada

In this work, hyperpolarized ³He and ¹²⁹Xe MRI was used to measure regional ventilation in the normal rat lung using the dynamic gas signal from inside the lungs. This method used a variable flip angle approach (FAVOR) to mitigate the effects of RF pulses and relaxation both in the ventilator system and in the rat lung. A theoretical model was used to fit signal enhancement curves on a pixel-by-pixel basis to generate two-dimensional maps of the ventilation parameter, r, which was defined as the fractional refreshment of gas per breath. Ventilation gradients were calculated in the superior/inferior and anterior/posterior directions.

Kai Ruppert¹, Jaime F. Mata¹, Isabel M Dregely², Talissa A Altes¹, G Wilson Miller¹, Stephen Ketel³, Jeff Ketel³, Iulian C Ruset^2,3, F William Hersman^2,3, and John P Mugler III^1
1University of Virginia, Charlottesville, VA, United States, ²University of New Hampshire, Durham, NH, United States, ³Xemed LLC, Durham, NH, United States

Due to the large chemical shift difference between hyperpolarized Xe129 (HXe129) dissolved in lung tissue and in the alveolar air spaces it is feasible to image both compartments simultaneously, appearing side-by-side in the image, by using a suitable imaging bandwidth. The weighting of the dissolved-phase contrast can be shifted from exchange-site dominant to blood-pool dominant through an adjustment of the TR/FA combination of the acquisition. Thereby it is feasible to monitor and quantify the HXe129 gas transport processes throughout the pulmonary and cardiovascular system up to the aortic arch.

Zackary I Cleveland¹, Harald E Moller^1,2, Laurence W Hedlund¹, John Nouls¹, Matthew Freeman^1,3, Yi Qi¹, and Bastiaan Driehuys^1
1Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States, ²Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ³Graduate Program in Medical Physics, Duke University, Durham, United States

We demonstrate that 3D images of both ventilation and pulmonary perfusion can be acquired in rats using hyperpolarized 129Xe. To generate the perfusion images, 129Xe was infused into the blood using an extracorporeal circuit containing a hydrophobic membrane based, gas exchange module. The spatial resolution of these perfusion images (2×2×2 mm3) is similar to that obtained from conventional nuclear imaging modalities, but can be acquired with a five-fold advantage in temporal resolution. Thus, 129Xe MRI can be used to rapidly assess the distribution of ventilation and perfusion and will be useful in investigating animal models of acute lung disease.

Jaime Mata¹, Kai Ruppert¹, Peter Sylvester¹, Isabel Dregely², Talissa Altes¹, Iulian Ruset², William Hersman², Grady Miller¹, steve Ketel², Jeff Ketel², and John Mugler III^1
1Radiology, University of Virginia, Charlottesville, Virginia, United States, ²Xemed, LLC, Durham, NH, United States

Using hyperpolarized Xe-129 gas and Chemical Shift Imaging, we directly calculate images reflecting the amount of Xe-129 in the airspaces, and dissolved in the lung tissue, Red Blood Cells (RBC), and other compartments, thus obtaining detailed spatial information regarding how Xe-129 is distributed in those different compartments and providing regional information about lung physiology.

Mathieu Boudreau^1,2, Xiaojun Xu³, William Dominguez-Viqueira⁴, and Giles Santyr^1,5
1Imaging Research Laboratories, John. P. Robarts Research Institute, London, Ontario, Canada, ²Dept. of Physics and Astronomy, University of Western Ontario, London, Ontario, Canada,³University of Sheffield, Sheffield, United Kingdom, ⁴Imaging Research, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada, ⁵Dept. of Medical Biophysics, University of Western Ontario, London, Ontario, Canada

The apparent diffusion coefficient (ADC) of hyperpolarized noble gases has been demonstrated to behave anisotropically in the lung. In this work, we investigate hyperpolarized ¹²⁹Xe gas ADC anisotropy in vivo at 74 mT in an elastase-instilled rat model of emphysema. The effect of diffusion time (6 and 100 ms) on ¹²⁹Xe anisotropic ADC was quantified using the Yablonskiy model in sham instilled and elastase-instilled rats. The largest change in D_L was observed at 100 ms (13% increase for the elastase compared to the sham rats), and for D_T at 6 ms a 25% increase was observed.

Alexei V Ouriadov¹, Matthew Fox^1,2, Lanette Friesen-Waldner³, Charles McKenzie^3,4, and Giles Santyr^3,5
1Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada, ²The Department of Physics, The University of Western Ontario, ³The Department of Medical Biophysics, The University of Western Ontario, ⁴Biomedical Engineering Program, The University of Western Ontario, ⁵Robarts Research Institute, The University of Western Ontario

MR imaging using hyperpolarized 129Xe provides non-invasive approach for probing lung structure and function. In addition to this 129Xe is able to diffuse across the blood-gas barrier giving rise to CS in compartments such as tissue/RBC. So measurements of ventilation(V), perfusion(Q) and diffusing capacity of xenon(DXe) are possible. In order to obtain simultaneous V, Q and DXe maps we propose to use modified Dixon method called IDEAL. The preliminary results obtained from the rat lung demonstrate the feasibility of using IDEAL for simultaneous hyperpolarized 129Xe imaging of the gas signal and the signal from the tissue/RBC compartments in the lung.

Sean Alexander Lourette¹, Allen W Che², Jason C Woods^1,2, and Mark S Conradi^1,2
1Physics, Washington University, St. Louis, Missouri, United States, ²Radiology, Washington University, St. Louis, Missouri, United States

To reduce the cost of hyperpolarized ³He MR experiments, used for measuring restricted diffusion, ventilation uniformity, and oxygen distribution in lungs, ³He should be recaptured and purified for reuse in future experiments. A device has been constructed that collects exhaled gas into flexible bags, using activated carbon to remove N₂, O₂, and other exhaled contaminants from the³He by means of physical adsorption at 77 K. The purified ³He is cryogenically recompressed, mixed with nitrogen buffer gas, and used to refill Rb-glass cells for hyperpolarization.

Jan Henrik Ardenkjaer-Larsen¹, Haukur Johannesson¹, Jan Wolber², Nick Kuzma³, and Rahim Rizi^3
1GE Healthcare, Broendby, Denmark, ²GE Healthcare, United Kingdom, ³University of Pennsylvania, United States

It is demonstrated that the dissolution-DNP method is capeable of producing Xenon gas with high polarization in the gas phase. The maximum obtained solid state 129Xe polarization was 23%. The method would allow for high production rates of Xenon gas with high polarization.

Steven Richard Parnell¹, Martin H Deppe¹, Juan Parra-Robles¹, and Jim M Wild^1
1Academic Radiology, University of Sheffield, Sheffield, South Yorkshire, United Kingdom

A high power narrow line width external cavity diode laser is investigated for rubidium spin exchange optical pumping of 129Xe. This tunable photon source has a constant line width, independent of operating power or wavelength within a 1 nm tuning range. When using this laser, an increase in the 129Xe nuclear polarisation is observed when optically pumping at a lower wavelength than the measured Rb absorption. The exact detuning from the absorption for the highest polarisation is dependent upon the gas density. Furthermore, at high power and/or high Rb density, a reduction of the polarisation occurs at the optimum wavelength as previously reported in SEOP studies of 3He which is consistent with high absorption close to the cell front face. These results are encouraging for moderate high throughput polarisation of 129Xe in the mid pressure range.

F. W. Hersman^1,2, Jan H Distelbrink², Jeff Ketel², David Watt², Stephen Ketel², Walter Porter², Steve Bryn², Aaron Hope², and Iulian Constantin Ruset^2
1Department of Physics, University of New Hampshire, Durham, NH, United States, ²Xemed LLC, Durham, NH, United States

Hyperpolarized gases xenon-129 and helium-3 are novel imaging agents for pulmonary functional MRI that are in investigational use in clinical research. Producing these gases with spin-exchange optical pumping (SEOP) requires high power laser sources spectrally narrowed at 795nm. We present a new implementation of optical elements incorporated in an external cavity spectrally-locked diode laser system and report measurements confirming production of 1.5 kilowatt laser power with spectral width of less than 0.2nm at 795nm central wavelength and angular divergence less than 0.1mr (fast axis) X 5mr (slow axis).

Puttisarn Mongkolwisetwara¹, Evguenia Borissova Arguiri², Kiarash Emami¹, Yi Xin¹, Nicholas N. Kuzma¹, Stephen J. Kadlecek¹, Yinan Xu¹, Harilla Profka¹, Melpo Christofidou-Solomidou², Milton D Rossman², Masaru Ishii³, and Rahim R. Rizi^4
1Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States, ²Pulmonary Division, University of Pennsylvania, Philadelphia, Pennsylvania, United States, ³Otolaryngology–Head & Neck Surgery, Johns Hopkins University, Baltimore, Maryland, United States, ⁴Radiology, University of Pennsylvania, Philadelphia, Pennsylvania

Idiopathic Pulmonary Fibrosis (IPF) is a relatively rare and most debilitating disease due to the fact that it is a progressive disorder whose pathogenesis is still unknown. Therefore, determining the causes of IPF and finding a probe to monitor potential treatments are essential goals of this study. The pulmonary function measurement by 3He MRI is a sensitive tool in assessing lung microstructure and function. Significant changes in all parameters of alveolar partial pressure, ADC, and fractional ventilation confirm that we can employ 3He MRI to gauge microstructure (ADC changes), lung function (Fractional Ventilation) and deficient in O2 uptake in alveolar walls (PaO2).

Yi Xin¹, Kiarash Emami¹, Stephen J. Kadlecek¹, Puttisarn Mongkolwisetwara¹, Nicholas N. Kuzma¹, Harilla Profka¹, Yinan Xu¹, Hooman Hamedani¹, Benjamin M. Pullinger¹, Rajat K. Ghosh¹, Jennia N. Rajaei¹, Stephen Pickup¹, Masaru Ishii², and Rahim R. Rizi^1
1Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States, ²Otolaryngology–Head & Neck Surgery, Johns Hopkins University, Baltimore, Maryland, United States

We present measurements of lung microstructure using ³He Apparent Diffusion Coefficient (ADC) and Ventilation in smoked mice. After six months of smoke exposure, the smoke-exposed group has significantly larger ADC values, while the ventilation maps are visually and quantitatively unchanged. We conclude that this smoked mice model more closely resembles the disease model in human emphysematous rather than human chronic bronchitic disease.

Amy Barulic¹, Kiarash Emami², Yi Xin¹, Puttisarn Mongkolwisetwara¹, Harilla Profka¹, Nicholas N. Kuzma¹, Jeanine M. D'Armiento³, Takayuki Shiomi⁴, Stephen J. Kadlecek¹, Yinan Xu¹, Hooman Hamedani¹, Benjamin Michael Pullinger¹, Rajat Ghosh¹, Jennia Rajaei¹, Stephen Pickup¹, Masaru Ishii⁵, and Rahim R. Rizi^1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Radiology, University of Pennsylvania, PA, Pennsylvania, United States, ³Departments of Medicine and Surgery, Columbia University, New York, NY, United States, ⁴Department of Molecular Medicine, Columbia University, New York, NY, United States, ⁵Otolaryngology–Head & Neck Surgery, Johns Hopkins University, Baltimore, MD, United States

Hyperpolarized ³He gas MRI was used to assess the SFRP1 knockout mice lung microstructure. SFRP1 knockout mice demonstrated a significant increase in the overall ³He apparent diffusion coefficient value compared to their naïve counterparts. Results suggest that this technique can serve as a sensitive and non-invasive in vivo imaging tool for longitudinal studies of development and repair response in pulmonary cells, as well as for the study of lung embryogenesis and monitoring the progression of therapeutic interventions for various lung pathologies.

Kiarash Emami¹, Jennia N. Rajaei¹, Yi Xin¹, Puttisarn Mongkolwisetwara¹, Harilla Profka¹, Stephen J. Kadlecek¹, Hooman Hamedani¹, Yinan Xu¹, Amy Barulic¹, Stephen Pickup¹, Nicholas N. Kuzma¹, Blerina Ducka², Angela Haczku², Masaru Ishii³, and Rahim R. Rizi^1
1Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States, ²Pulmonary & Critical Care Division, University of Pennsylvania Medical Center, Philadelphia, PA, United States,³Otolaryngology–Head & Neck Surgery, Johns Hopkins University, Baltimore, Maryland, United States

Regional measurements of fractional ventilation provide a sensitive and noninvasive tool for studying physiological changes which occur within the asthmatic lung. Evidence shows a statistically significant decline in regional ventilation for the asthmatic cohort compared to that of the naïve and control cohorts, while ADC values did not exhibit a similar decline, indicating that airway remodeling which contributes to lower ventilation is a result of asthmatic responses. Results indicate that hyperpolarized gas MRI and the quantitative measurements obtained from it may yield promising advances in early detection and diagnosis of asthma.

Wei Wang^1,2, Nguyet M. Nguyen³, Dmitriy A. Yablonskiy^1,2, Alexander L. Sukstanskii², Emir Osmanagic², Richard A. Pierce³, Mark S. Conradi^1,2, and Jason C. Woods^1,2
1Physics, Washington University in St. Louis, St. Louis, MO, United States, ²Radiology, Washington University in St. Louis, St. Louis, MO, United States, ³Internal Medicine, Washington University in St. Louis, St. Louis, MO, United States

Quantitative measurement of lung microstructure is of great significance in assessment of pulmonary disease, particularly in the earliest stages. Our MRI-based 3He lung morphometry technique was previously developed and validated for human lungs, and was recently extended to ex-vivo mouse lungs. The technique yields accurate, quantitative information about the microstructure and geometry of acinar airways. In this study the 3He lung morphometry technique is successfully implemented for in-vivo studies of mice. Results indicate excellent agreement between in-vivo morphometry via 3He MRI and microscopic morphometry after sacrifice. This opens up new avenues for application of the technique as a precise, noninvasive, in-vivo biomarker of changes in lung microstructure, within various mouse models of lung disease.

Laura Carrero-Gonzalez^1,2, Thomas Kaulisch¹, Jesus Ruiz-Cabello^2,3, Jose Manuel Perez-Sanchez⁴, German Peces-Barba⁵, Detlef Stiller¹, and Ignacio Rodriguez^2,3
1Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Baden-Württemberg, Germany, ²Universidad Complutense de Madrid, Madrid, Spain, ³CIBER de Enfermedades Respiratorias, Madrid, Spain, ⁴Unité de Recherche en Résonance Magnétique Médicale (UMR 8081), Univ.Paris-Sud, CNRS, Orsay, France, ⁵Fundación Jiménez-Díaz, Madrid, Spain

Apparent diffusion coefficient (ADC) of HP-gases is a parameter that reflects changes in lung microstructure but it depends on many physiological and experimental variables. The application of a positive end expiratory pressure (PEEP) causes an increase of the residual volume. If incoming and residual gases do not have similar diffusion coefficient, the obtained ADC values will be affected. A proposed single breath-hold protocol uses 4He-O2 for ventilation and HP3He-N2 for imaging. Both gas mixtures have a very similar diffusion coefficient. ADCs obtained from the proposed strategy show to be independent of PEEP, thus minimizing the effect of the different residual volumes.

Adam J Hajari^1,2, Alex L Sukstanskii², Dmitriy A Yablonskiy^1,2, Richard A Pierce³, Gaetan Deslee⁴, and Jason C Woods^1,2
1Physics, Washington University, St. Louis, MO, United States, ²Radiology, Washington University, St. Louis, MO, United States, ³Internal Medicine, Washington University, St. Louis, MO, United States, ⁴Service de Pneumologie, INSERM U903, Reims, France

In this study we have measured alveolar and acinar duct sizes at physiologically relevant volumes in six normal excised canine lungs using a ³He lung morphometry technique optimized for measurements of canine sized airways. Our results imply that during a significant decrease in lung volume (from TLC to 63% of TLC), the acinar duct radius decreases by 17% while the alveolar depth increases by 9%. The ³He morphometry results are in good agreement with histology measurements of the same parameters from the same lungs.

Laura Carrero-Gonzalez^1,2, Thomas Kaulisch¹, Jesus Ruiz-Cabello^2,3, Detlef Stiller¹, and Ignacio Rodriguez^2,3
1Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Baden-Württemberg, Germany, ²Universidad Complutense de Madrid, Madrid, Spain, ³CIBER de Enfermedades Respiratorias, Madrid, Spain

Apparent diffusion coefficient (ADC) reflects changes in lung microstructure and it is used as a detector of lung diseases. Instillation of elastase in the lung produces emphysema, which is characterized by higher airspaces, higher compliance and higher residual volume compared to healthy tissue. It has been proved the feasibility of instilling elastase in only one lung using the other lung of the rat as an internal control. ADC values from elastase-treated and healthy lungs showed significant differences at the end of the expiration, but not during a full-inspiration breath-hold (23mbar). A special ventilation protocol reduces the effect on the ADC due to the different diffusivity of mixtures with either different gases composition or different gases concentration.

Maurizio F. Cereda¹, Kiarash Emami², Stephen J. Kadlecek², Yi Xin², Puttisarn Mongkolwisetwara², Harilla Profka², Amy Barulic², Stephen Pickup², Nicholas N. Kuzma², Masaru Ishii³, Hooman Hamedani², Benjamin M Pullinger², Rajat Ghosh², Jennia Rajaei², Clifford S. Deutschman¹, and Rahim R. Rizi^2
1Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania, United States, ²Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States,³Otolaryngology–Head & Neck Surgery, Johns Hopkins University, Baltimore, Maryland, United States

Atelectasis, often caused by a mechanical ventilator, promotes lung injury, whose mechanisms are not fully understood. Understanding these underlying mechanisms requires simultaneous measurements of ventilated air space and alveolar size, which can be achieved through the use of hyperpolarized gas MRI technology. Additionally, this technique can show how alveolar recruitment maneuvers reestablish a normal pattern of airspace inflation.

Puttisarn Mongkolwisetwara¹, Kiarash Emami¹, Hooman Hamedani¹, Harilla Profka¹, Yi Xin¹, Yinan Xu¹, Nicholas N. Kuzma¹, Stephen J. Kadlecek¹, Masaru Ishii², and Rahim R. Rizi^1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Otolaryngology–Head & Neck Surgery, Johns Hopkins University, Baltimore, MD, United States

An observable change in alveolar partial pressure of oxygen between controlled and elastase-induced mice shows that our measurement of alveolar partial pressure of oxygen by ³He MRI is sensitive enough to differentiate between diseased and normal animals. This confirms that we can utilize ³He's ability to interact with excessive oxygen partial pressure due to the damaged alveolar walls of elastate-induced mice. Likewise, the decrease in fractional ventilation and the increase in mean linear intercept in diseased mice by 14.29% and 34.66% verifies the abnormality in the lung function stemming from the disease.

John Nouls^1,2, Erin Potts³, W Michael Foster³, and Bastiaan Driehuys^1,2
1Department of Radiology, Duke University, Durham, NC, United States, ²Center for in vivo Microscopy, Duke University, Durham, NC, United States, ³Department of Pulmonary and Critical Care Medicine, Duke University

Ambient ozone (O₃) is a major environmental air pollutant, which significantly impacts public health and exacerbates disease in subjects with asthma and chronic obstructive pulmonary disease. While much is known about the deleterious effect of O₃ on global lung function, much less is understood about its effects regionally. To this end hyperpolarized gas MRI has been proposed as an ideal means to address this gap. Here, we demonstrate high-resolution 3D ³He and ¹H MRI in ozone-exposed C57BL/6 mice reveals striking regional ventilation impairment and bronchial narrowing.

Zackary I Cleveland¹, S Sivaram Kaushik^1,2, Gary P Cofer¹, John Nouls¹, Monica Kraft³, Jan Wolber⁴, H Page McAdams⁵, and Bastiaan Driehuys^1
1Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States, ²Department of Biomedical Engineering, Duke University, Durham, NC, United States, ³Department of Medicine, Duke University Medical Center, Durham, NC, United States, ⁴GE Healthcare, Amersham, United Kingdom, ⁵Department of Radiology, Duke University Medical Center, Durham, NC, United States

We investigate the signal intensity distribution in dissolved 129Xe images from healthy subjects and subjects with chronic obstructive pulmonary disease (COPD). In addition to gravity-dependent SNR gradients, images from healthy subjects display significant isogravitational heterogeneity as measured by the coefficient of variation (CV). Differences in SNR and CV are observed between the left and right lungs. Left-right differences are absent in ventilation images, suggesting tissue compression by the heart alters the signal distribution in the left lung. Gravitational and left-right differences are reduced or absent in subjects with COPD, indicating dissolved 129Xe is sensitive to disease-associated changes in lung physiology.

Martin H. Deppe¹, Salma Ajraoui¹, and Jim M. Wild^1
1Academic Unit of Radiology, University of Sheffield, Sheffield, South Yorkshire, United Kingdom

Auto-calibration is essential in Parallel Imaging of the human lung using hyperpolarized noble gases due to limitations of breath-hold reproducibility and gas consumption, resulting in a scan time overhead due to the acquisition of auto-calibration lines. This work presents results on Parallel Imaging of hyperpolarized 3He in human lungs using the SPIRiT reconstruction method, showing that this approach maintains image quality better for high net acceleration factors than the commonly used GRAPPA method. As SPIRiT is an iterative optimization method, the inclusion of random sampling and L1-penalization (Compressed Sensing) is straightforward.

Stanley John Kruger¹, David Niles¹, Grace Parraga², Sean Fain¹, Bernard Dardzinski³, Marcella Ruddy³, Amy Harman³, Stephen Choy², Scott Nagle⁴, Christopher Francois⁴, David G McCormack², and Nizar Jarjour^5
1Medical Physics, University of Wisconsin, Madison, WI, United States, ²Robarts Imaging Institution, University of Western Ontario, London, ON, Canada, ³Merck Research Labs, West Point, PA, United States, ⁴Radiology, University of Wisconsin, Madison, WI, United States, ⁵Medicine and Public Health, University of Wisconsin, Madison, WI, United States

A double blind therapy trial using He-3 MRI was conducted to evaluate efficacy for exercise induced bronchoconstriction (EIB) using images of ventilation. To track regional changes in defect volume as an endpoint for treatment effect, He-3 MRI was performed at three separate visits at baseline, exercise challenge and 45 min. after challenge in 13 subjects with EIB. Drug was given at 1 of the visits, and placebo at the remaining visits. Results show decreases in ventilation volume at exercise challenge compared to baseline, with treatment reducing this effect. Both decrease in ventilation volume and treatment effect showed preferential regional behavior.

David Joseph Niles¹, Stanley J Kruger¹, Grace Parraga^2,3, Bernard Dardzinski⁴, Marcella Ruddy⁴, Nizar N Jarjour⁵, David G McCormack⁶, Amy Harman⁴, and Sean B Fain^1,7
1Medical Physics, University of Wisconsin, Madison, WI, United States, ²Imaging Research Laboratories, Robarts Research Institute, University of Western Ontario, London, ON, Canada,³Medical Biophysics, University of Western Ontario, London, ON, Canada, ⁴Merck Research Laboratories, West Point, PA, United States, ⁵Pediatrics, University of Wisconsin, Madison, WI, United States, ⁶Division of Respirology, Department of Medicine, University of Western Ontario, London, ON, Canada, ⁷Radiology, University of Wisconsin, Madison, WI, United States

Hyperpolarized helium-3 magnetic resonance imaging (HPHe MRI) is a promising tool for evaluating regional ventilation in obstructive lung disorders; however, its reliability has not been thoroughly established. This study evaluates the reliability of HPHe MRI between exams on separate days and the inter-reader reliability of exams analyzed independently by two blinded readers. Reliability was quantified using the intraclass correlation coefficient (ICC) and a Bland-Altman analysis. Between-day ICC values for four image-based measurements were at least 0.61 and inter-reader ICC values were at least 0.91. These results indicate that HPHe MRI is robust between separate exams and independent evaluators.

Miranda Kirby^1,2, Roya Etemad-Rezai³, David G McCormack⁴, and Grace Parraga^1,5
1Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada, ²Medical Biophysics, The University of Western Ontario, London, Ontario, Canada, ³Department of Medical Imaging, The University of Western Ontario, London, Ontario, Canada, ⁴Division of Respirology, Department of Medicine, The University of Western Ontario, London, Ontario, Canada,⁵Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada

The objective of this study was to evaluate short-acting bronchodilator effects in fourteen subjects with chronic obstructive pulmonary disease (COPD) using hyperpolarized helium-3 (³He) magnetic resonance imaging (MRI), spirometry, and plethysmography before and after administration of salbutamol. ³He MRI ventilation segmentation was performed using a semi-automated k-means clustering algorithm and ³He ADC was calculated using diffusion-weighted imaging. ³He MRI detected significant reductions in ³He clusters that contained no or diminished MR signal (p<.0001) and significant improvements in ³He ventilation clusters (p<.05), but no changes in ³He ADC post-salbutamol (p=.56), indicating that regional distribution of ventilation improves in COPD patients post-bronchodilator.

Sarah Svenningsen^1,2, Miranda Kirby^1,2, Hassaan Ahmed^1,2, Nigel Paterson³, and Grace Parraga^1,4
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, ⁴Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada

With the recent rapid development of a wider array of cystic fibrosis (CF) treatment options there is an urgent requirement for precise, practical and sensitive clinical endpoint measures that can be used to determine treatment response and CF disease progression over time. With the generation of a semi-automated method for the determination of pulmonary ventilation in CF, the short-term (7+/- 2 days) precision and specificity of hyperpolarized ³He MRI measurements was evaluated. We were able to conclude that the semi-automated method provides superior precision for the detection of significant changes in pulmonary function over short periods of time.

Stephen Costella^1,2, Andrew Wheatley¹, David McCormack³, and Grace Parraga^1,2
1Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada, ²Graduate Program in Biomedical Engineering, University of Western Ontario, London, Ontario, Canada,³Medicine, Division of Respirology, University of Western Ontario, London, Ontario, Canada

Pulmonary functional imaging using helium-3 (3He) magnetic resonance imaging (MRI) has provided us with a way to quantitatively evaluate the spatial and temporal functional changes in a variety of respiratory conditions, including asthma. We quantitatively evaluated ventilation defect size and number at baseline, PC20 and after recovery and compared these values with spirometry. Our results suggest that mean defect size is the dominant mechanism for the changes in FEV1 that occur at PC20 as compared to defect count. This provides important new information on the mechanisms involved in asthma exacerbations and insights on prophylaxis to avoid exacerbations.

Ahsan Samiee¹, Stephen J. Kadlecek², Kiarash Emami², Yinan Xu², Hooman Hamedani³, Yi Xin², Puttisarn Mongkolwisetwara², Nicholas N. Kuzma², Per Åkeson⁴, Peter Magnusson⁵, Lise Vejby Søgaard⁵, Sandra Diaz⁶, Wilson Miller⁷, Milton D. Rossman⁸, Masaru Ishii⁹, and Rahim R. Rizi^2
1Mechanical and Aerospace Engineering, University of California, San Diego, San Diego, CA, United States, ²Radiology, University of Pennsylvania, Philadelphia, PA, United States, ³Radiology, University of Pennsylvania, Philadelphia, Philadelphia, United States, ⁴Danish Research Centre for Magnetic Resonance, Hvidovre Hospital, Hvidovre, Denmark, ⁵Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, ⁶Department of Clinical Sciences, Malmö University Hospital, Malmö, Sweden, ⁷Department of Radiology, University of Virginia, Charlottesville, Virginia, United States, ⁸Pulmonary, Allergy & Critical Care Division, University of Pennsylvania, Philadelphia, PA, United States, ⁹Otolaryngology–Head & Neck Surgery, Johns Hopkins University, Baltimore, MD, United States

Early diagnosis of emphysema is not a possibility with standard clinical tests. Noting the heterogeneity of the disease, CT and increasingly MRI-based imaging techniques have been proposed for this purpose, including measurements of Apparent Diffusion Coefficient (ADC) of respiratory gas. It has been shown that the mean ADC is fairly reproducible marker, which can clearly differentiate emphysematous lungs from healthy lungs. This approach can undesirably mask regional distribution and heterogeneity of abnormalities. This work presents a scalar metric sensitive to regional distributions of gas diffusion in airways while retaining as much of the heterogeneity information as possible.

Martin Heiner Deppe¹, Xiaojun Peggy Xu¹, Steven R. Parnell¹, and Jim M. Wild^1
1Academic Unit of Radiology, University of Sheffield, Sheffield, South Yorkshire, United Kingdom

Inert gas washout is a parameter well-known in lung physiology, but is typically measured only globally at the mouth, hence not containing any information on regional differences. Here we present a method capable of imaging the washout of inert gas from human lungs directly, using hyperpolarized 3He MRI. The resulting data can be analyzed to show the local washout rates for different regions of interest (such as for a traditional core/peel pattern) or on a pixel-by-pixel basis. The method is potentially able to provide important information on diseased lung regions in obstructive lung diseases.

Helen Marshall¹, Martin H Deppe¹, Juan Parra Robles¹, Steve R Parnell¹, Rob H Ireland¹, David Capener¹, Sue Hillis¹, Smitha Rajaram¹, Catherine Billings², David A Lipson³, Rod Lawson², and Jim M Wild^1
1Academic Radiology, University of Sheffield, Sheffield, South Yorkshire, United Kingdom, ²Respiratory Medicine, University of Sheffield, Sheffield, South Yorkshire, United Kingdom,³GlaxoSmithKline, King of Prussia, PA, United States

The combination of ³He ventilation and dynamic contrast enhanced (DCE) ¹H perfusion was investigated as a means to assess the matching of ventilation and perfusion (V/Q) in chronic obstructive pulmonary disease (COPD). ³He ventilation, ¹H DCE perfusion and anatomical ¹H images were acquired from four COPD patients at 1.5T. Ventilated and perfused tissue volumes were calculated as a percentage of total lung volume. Regions of ventilation and perfusion were generally well matched but some areas of V/Q mismatch were also detected. These methods visualise regional V/Q distributions well, and may provide a means of quantitative therapy response evaluation in COPD.

Kun Qing¹, Grady Wilson Miller^2,3, Talissa Altes², Jaime F. Horta Coelho Mata², Eduard E. De Lange², William A. Tobias³, Gordon D. Cates³, James R. Brookeman², and John Philip Mugler^1,2
1Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, ²Radiology, University of Virginia, ³Physics, University of Virginia

Use of an SLR pulse for phase-based transmitter calibration is predicted to provide more accurate results than those from hard or Fermi pulses, especially for a range of off-resonance values and relatively low peak B1. For transmitter calibration prior to hyperpolarized He3 lung imaging, this approach showed good agreement with an established amplitude-based method. In contrast to the amplitude-based method, the phase-based method uses only a small fraction of the available hyperpolarized magnetization and requires less than 100 ms, and thus could be prepended to a lung-imaging pulse sequence, obviating the need for a dedicated calibration.

Jim M Wild¹, Martin H Deppe¹, Salma Ajraoui¹, Helen Marshall¹, Graham Norquay¹, Titus Lanz², Matthias Behr², Francesco Padormo³, Juan Parra-Robles¹, and Sebastian Kozerke^4
1University of Sheffield, Sheffield, Yorkshire, United Kingdom, ²Rapid Biomedical, ³Imperial College, United Kingdom, ⁴Imaging Sciences, Kings College London

Hyperpolarised gas MRI is highly sensitive to RF flip angle (FA) and B1+ homogeneity, thus accurate knowledge of the delivered flip angle and a spatially homogeneous B1+ field are both highly desirable. Chest birdcage coils have been developed for both 3He and 129Xe lung MRI at 1.5T providing homogenous B1+ fields over the lung FOV. In 1H multi-transmit coil imaging of the abdomen at 3T, modulation of the delivered B1+ has been reported as a function of breathing cycle. In this work the effect of lung inflation upon the B1+ field delivered by two 3He chest birdcage coils was investigated at 1.5T and 3T.

Mathieu Sarracanie¹, Denis Grebenkov², Soule Coulibaly¹, Andrew Martin³, Kyle Hill⁴, Jose Manuel Perez-Sanchez¹, Redouane Fodil⁵, Lionel Martin¹, Emmanuel Durand¹, Georges Caillibotte³, Daniel Isabey⁵, Luc Darrasse¹, Jacques Bittoun¹, and Xavier Maitre^1
1IR4M (UMR8081), Univ Paris-Sud, CNRS, Orsay, France, ²Laboratoire de Physique de la Matiere Condensee (UMR7643), Ecole Polytechnique, CNRS, Palaiseau, France, ³Centre de Recherche Claude Delorme (CRCD), Air Liquide, Les Loges-en-Josas, France, ⁴Radiology Research Group, Oxford MRI Centre, Oxford University, Oxford, United Kingdom, ⁵Biomecanique Cellulaire et Respiratoire (U955), IMRB, Inserm, Creteil, France

One of the key challenges in the study of health-related aerosols is predicting and monitoring sites of particle deposition in the airways. Recent work in MRI has shed light on techniques to quantify magnetic particles in living bodies by the measurement of associated static magnetic field variations. Dealing with lung MRI, hyperpolarized helium-3 may be used to compensate for the lack of signal in the airways, so as to allow assessment of pulmonary function and morphology. In the present work, aerosol deposition in a mouth-throat phantom measured using helium-3 MRI was correlated with computational fluid dynamics simulations and gamma scintigraphy.

Niels Buhl^1,2, and Sune Nørhøj Jespersen^2
1Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark, ²Center of Functionally Integrative Neuroscience, Aarhus University Hospital, Aarhus, Denmark

We present an analytical treatment of long time scale diffusion weighted MRI of the human lung. Diffusion in the airways of the lung is modeled as diffusion on a network of connected line segments, with the relative position of each line segment given by the symmetric branching geometry. Within this model we are able to average the time dependent diffusion coefficient over all airways of the acinar region. The theory is in good agreement with published 3He long time scale measurements, provided the latter may be treated as roughly satisfying the Gaussian phase approximation.

Juan Parra-Robles¹, Steven R Parnell¹, Salma Ajraoui¹, Xiaojun Xu¹, and Jim M Wild^1
1Academic Radiology, University of Sheffield, Sheffield, South Yorkshire, United Kingdom

Due to their different diffusivities , ³ and ¹²⁹Xe are sensitive to different length scales of acinar structure. In this work, we investigate short-range ¹²⁹Xe diffusion in a model of acinar airways using finite element computer simulations. The results suggest that ¹²⁹Xe short range diffusion experiments may be more sensitive to alveolar structure than ³He, while being less sensitive to branching effects. This may simplify the development of ¹²⁹Xe-based MR lung morphometry techniques, which could be based on a two compartment model.

Juan Parra-Robles¹, Steven R Parnell¹, Salma Ajraoui¹, Xiaojun Xu¹, and Jim M Wild^1
1Academic Radiology, University of Sheffield, Sheffield, South Yorkshire, United Kingdom

In this work, we use finite element simulations of diffusion in a model of branching alveolar ducts to investigate in detail the effects of acinar branching structure on short-range ³He diffusion measurements. The obtained results indicate that branching effects have significant influence in ³He diffusivity, even at short diffusion times. The cylinder model theory do not account for significant dependences upon diffusion time, branching geometry and airway length; and further development and validation is required.

Kai Ruppert¹, Ching-Ling Teng¹, Isabel M Dregely², Jaime F. Mata¹, Talissa A Altes¹, G Wilson Miller¹, and John P Mugler III^1
1University of Virginia, Charlottesville, VA, United States, ²University of New Hampshire, Durham, NH, United States

Over the years Xenon polarization Transfer Contrast (XTC) MRI has been implemented in several different variants that conceptually all measure the same quantities. Expanding on recent work by Hrovat et al we investigated how specific XTC MRI sequence implementations and violations of the underlying model assumptions affect the measured quantities using numerical simulations. We found that the delay time between consecutive contrast-generating RF pulse pairs should be held constant and the flip angle should be at least 120° to minimize measurement errors.

Yogesh kannan Mariappan¹, Arunark Kolipaka¹, Rolf D Hubmayr², Richard L Ehman¹, Phillip Araoz¹, and Kiaran P McGee^1
1Department of Radiology, Mayo Clinic, Rochester, MN, United States, ²Department of Pulmonary and Critical Care medicine, Mayo Clinic, Rochester, MN, United States

Magnetic Resonance Elastography (MRE) is being investigated for the quantification of lung parenchymal mechanical properties. Previous small animal experiments using invasive drivers have indicated that ¹H based MRE can quantitate lung shear modulus. This technique was extended to an in situ porcine model with a noninvasive driver placed on the chest wall and was tested to measure the change in stiffness as a function of airway opening pressure (P_ao) in 10 adult pigs. Shear stiffness increased with increasing P_ao, in agreement with theory. It is concluded that in an in situ porcine lung, ¹H MRE can quantitate shear stiffness as a function of P_ao.

Oliviero Gobbo¹, Magdalena Zurek², Frederic Tewes¹, Carsten Ehrhardt¹, and Yannick Crémillieux^2
1School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, Dublin 2, Ireland, ²University of Lyon, CREATIS-LRMN, Lyon, France

A new approach for T1-enhancemened rat lung MR imaging, was evaluated. This technique uses a manganese-based contrast agent combined with a very short echo-time radial MRI. Different concentrations of a contrast agent were investigated. A significant signal intensity enhancement was observed in the MnCl2-instilled lung versus control animals. The manganese can be use as an efficient contrast agent for lung MRI.

Laura Schreiber¹, Maxim Terekhov¹, Uschi Wolf², Alexander Scholz¹, Julien Rivoire¹, Rainer Köbrich³, Janet Friedrich¹, Florian Meise¹, Sergej Karpuk⁴, Lars Krenkel⁵, and Claus Wagner^5
1Section of Medical Physics, Johannes Gutenberg University Medical Center, Mainz, Germany, ²Department of Radiology, Johannes Gutenberg University Medical Center, Mainz, Germany,³Maquet GmbH, Rastatt, Germany, ⁴Institute of Physics, Mainz University, Mainz, Germany, ⁵Institute of Aerodynamics and Flow Technology, German Aerospace Center, Göttingen, Germany

MRI during HFOV provides insight into slow and rapid gas transfer processes in the lung. Gas transfer processes are less effective at 10 Hz than at 5 Hz. Results of measurements with hyperpolarized 3He and C4F8 gas give similar results. Differences between the physical characteristics (e.g., density, viscosity, diffusion coefficient) of the contrast gases 3He and C4F8, when compared with those of the respiratory gases O2 and CO2, need to be considered in the interopretation of the results. In conclusion, contrast gas based MRI is a new tool to visualize and analyze intrapulmonary gas transport processes during artifical ventilation.

Olaf Dietrich¹, Sven F. Thieme², Daniel Maxien², Konstantin Nikolaou², Stefan O. Schoenberg³, Maximilian F. Reiser^1,2, and Christian Fink^3
1Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, Ludwig Maximilian University of Munich, Munich, Germany, ²Department of Clinical Radiology, Ludwig Maximilian University of Munich, Munich, Germany, ³Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Mannheim, Germany

The feasibility of oxygen-enhanced lung MRI (O₂-MRI) at 3 Tesla was assessed and compared to 1.5 Tesla. 13 volunteers underwent O₂-MRI at 1.5 and 3 Tesla. The mean relative signal enhancement due to oxygen inhalation was 13% (± 5.6%) at 1.5 T and 9.0% (± 8.0%) at 3 T. The regional coefficient of variation was significantly higher at 3 T due to a considerably less homogeneous signal-enhancement distribution. The SNR showed a trend to slightly higher values at 3 T. Oxygen-enhanced pulmonary MRI is feasible at 3 Tesla; however, the signal enhancement is more heterogeneous and slightly lower than at 1.5 T.

Ding Xia¹, Elan J. Grossman^1,2, Ke Zhang¹, Jian Xu³, Kenneth I Berger⁴, Roberta M Goldring⁴, Alexandra Stabile⁴, Larry Daugherty⁵, Kellyanne McGorty¹, and Qun Chen^1
1Center for Biomedical Imaging, Department of Radiology, NYU School of Medicine, New York, New York, United States, ²Department of Physiology and Neuroscience, NYU School of Medicine, New York, New York, United States, ³Siemens Medical Solutions, Malvern, Pennsylvania, United States, ⁴Department of Medicine, NYU School of Medicine, New York, New York, United States,⁵Dept of Radiology, University of Pennsylvania, Philadelphia, PA, United States

When airway abnormalities are localized only to the distal airways clinical-pathologic correlation between patient illness and lung disease has been difficult to establish. The current study establishes differences in regional lung measurements for patients with known or suspected distal airway dysfunction from controls based on a tissue tracking MRI technique and optical flow method. Our results show that while additional improvement in both data acquisition and data analysis are still required to make the current approach robust, the potential of using tissue tracking MRI for early detection of distal airway appears to be significant.

Stefan Weick¹, Philipp Ehses², Martin Blaimer², Felix A Breuer², and Peter M Jakob^1,2
1Experimental Physics 5, University of Wuerzburg, Wuerzburg, Bavaria, Germany, ²Research Center for Magnetic Resonance Bavaria (MRB), Wuerzburg, Germany

In this work, the human lung was examined under free breathing conditions using the k-space center signal for retrospective respiratory self-gating. The partition and phase encoding of a 3D FLASH sequence were played out in a quasi-random order. The quasi-random sampling results in improved ghost artifact reduction and leads to a very uniformly distribution of missing lines in k-space enabling successful iterative GRAPPA reconstruction. It is shown that the combination of retrospective self-gating with quasi-random sampling is a more robust strategy than the combination with conventional sampling allowing for better image quality in shorter scan time.

Samuel Patz¹, and James P. Butler^1,2
1Radiology, Brigham and Women's Hospital, Boston, MA, United States, ²Environmental Health, Harvard School of Publich Health, Boston, MA, United States

Fourier Decomposition proton MRI for the lung is a promising method that measures proton density changes synchronous with ventilation and heart rate, producing images related to “ventilation” and “perfusion”. There is, however, an additional degree of freedom insofar as blood and tissue volume change independently during ventilation; this has not been considered. Here we analyze the effect of a change in both regional gas volume as well as regional blood volume from a ventilation-only maneuver. We also describe a method to separate the two effects and show this can be used to increase the diagnostic utility of the method.

Grzegorz Bauman¹, and Sebastian Kozerke^2,3
1Division of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany, ²Division of Imaging Sciences, King's College London, London, United Kingdom, ³Institute for Biomedical Engineering, University and ETH Zurich, Switzerland

As a consequence of the recent shortage of ³He gas for lung imaging studies, alternative methods for the assessment of pulmonary function have received much attention. A very promising approach utilizes time-resolved ultra-short echo time data acquisitions of the native proton signal using a balanced steady-state free-precession (bSSFP) sequence with subsequent image registration and Fourier decomposition to construct perfusion and ventilation-weighted images. The objective of this work is to study the feasibility of k-t undersampling in conjunction with thek-t PCA reconstruction framework for accelerating dynamic bSSFP image acquisition of the lung.

Olaf Dietrich¹, Michael Ingrisch¹, Michael Peller¹, Konstantin Nikolaou², and Maximilian F. Reiser^1,2
1Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, Ludwig Maximilian University of Munich, Munich, Germany, ²Department of Clinical Radiology, Ludwig Maximilian University of Munich, Munich, Germany

Several different block paradigms with different numbers of blocks (of oxygen and room air administration) and different block durations have been used in oxygen-enhanced MRI (O₂-MRI) of the lung. The purpose of this study was to compare different block paradigms in simulations based on parameters taken from measurements in 11 volunteers to find the optimal design for the evaluation of dynamic O₂-MRI data, i.e. for pixelwise fitting of the signal enhancement and the wash-in/out times. Optimal results were obtained with 15 baseline scans (breathing air), followed by 50 scans breathing pure oxygen and by 15 final scans breathing air.

Chris James Rose^1,2, Penny Louise Hubbard^1,2, Caleb Roberts^1,2, Simon S Young³, Josephine H Naish^1,2, and Geoffrey J Parker^1,2
1The University of Manchester Biomedical Imaging Institute, The University of Manchester, Manchester, Greater Manchester, United Kingdom, ²Manchester Academic Health Science Centre, The University of Manchester, Manchester, Greater Manchester, United Kingdom, ³AstraZeneca R&D Charnwood, Loughborough, Leicestershire, United Kingdom

Voxel-wise measurements of ventilation-to-perfusion ratio (V/Q) in the lung can be made using oxygen-enhanced MRI (OE-MRI). Patients are dynamically imaged as they switch from breathing medical air to an elevated concentration of oxygen. The change in partial pressure of oxygen over time is modelled in terms of three parameters, v, q, and λ_B. We consider fitting this model to data and study the topology of the sum of squared differences (SSD) function. We demonstrate a valley in the SSD function of optimal v and q values satisfying v/q=V/Q, and show that v andq should not be interpreted independently.

Magdalena Zurek¹, Laurent Boyer², Philippe Caramelle², Jorge Boczkowski², and Yannick Crémillieux^1
1University of Lyon, CREATIS-LRMN, Lyon, France, ²INSERM U955, Paris, France

Tissue density losses and microstructural changes of the lung parenchyma present in emphysema disease can affect both, the MR image intensity and T2* values. Using an ultra-short echo-time (UTE) sequence, signal intensity and T2* changes were track in emphysema disease progression along an 8-weeks longitudinal study in elastase-challenged mice. The MR findings were confirmed by histology. The MR results are in good agreement with published CT observations and with predictions from a physical model. This technique is readily suitable for routine drug testing in experimental MR lung research of emphysema and can be transferred to human studies.

Hooman Hamedani¹, Kiarash Emami¹, Stephen J. Kadlecek¹, Yinan Xu¹, Yi Xin¹, Puttisarn Mongkolwisetwara¹, Amy Barulic¹, Nicholas N. Kuzma¹, Peter Magnusson², Lise Vejby Søgaard², Sandra Diaz³, Per Åkeson², Milton D. Rossman⁴, Masaru Ishii⁵, G. Wilson Miller⁶, and Rahim R. Rizi^1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark,³Department of Clinical Sciences, Malmö University Hospital, Malmö, Sweden, ⁴Pulmonary, Allergy & Critical Care Division, University of Pennsylvania, Philadelphia, PA, United States,⁵Otolaryngology–Head & Neck Surgery, Johns Hopkins University, Baltimore, MD, United States, ⁶Radiology, University of Virginia, Charlottesville, Virginia, United States

We have performed a reproducibility assessment for a newly improved high-resolution scheme for alveolar oxygen tension. Our results show that this P_AO₂ measurement by the HP ³He MRI is a reasonable approximation of the physiological P_AO₂ and is also reproducible.

Hooman Hamedani¹, Kiarash Emami¹, Stephen J. Kadlecek¹, Yinan Xu¹, Yi Xin¹, Amy Barulic¹, Puttisarn Mongkolwisetwara¹, Nicholas N. Kuzma¹, Peter Magnusson², Lise Vejby Søgaard², Sandra Diaz³, Per Åkeson², G. Wilson Miller⁴, Milton D. Rossman⁵, G. Wilson Miller⁶, and Rahim R. Rizi^1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark,³Department of Clinical Sciences, Malmö University Hospital, Malmö, Sweden, ⁴Radiology, University of Virginia, Charlottesville, VA, United States, ⁵Pulmonary, Allergy & Critical Care Division, University of Pennsylvania, Philadelphia, PA, United States, ⁶Department of Radiology, University of Virginia School of Medicine, Charlottesville, VA

A new higher-resolution multi-slice scheme for measuring regional partial pressure of oxygen in the lungs via HP ³He MRI is presented. This new scheme is based on eliminating the delay time needed to differentiate the effects of oxygen and RF pulses, instead making use of two interleaved back-to-back acquisitions for each slice. The resulting P_AO₂ errors are decreased by a factor of ~3 in this new scheme.

Yinan Xu¹, Hooman Hamedani¹, Kiarash Emami¹, Stephen J. Kadlecek¹, Yi Xin¹, Puttisarn Mongkolwisetwara¹, Amy Barulic¹, Nicholas N. Kuzma¹, Per Åkeson², Peter Magnusson³, Lise Vejby Søgaard³, Sandra Diaz⁴, Milton D. Rossman⁵, Wilson Miller⁶, Masaru Ishii⁷, and Rahim R. Rizi^1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Danish Research Centre for Magnetic Resonance, Hvidovre Hospital, Hvidovre, Denmark, ³Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, ⁴Department of Clinical Sciences, Malmö University Hospital, Malmö, Sweden, ⁵Pulmonary, Allergy & Critical Care Division, University of Pennsylvania, Philadelphia, PA, United States, ⁶Department of Radiology, University of Virginia, Charlottesville, Virginia, United States, ⁷Otolaryngology–Head & Neck Surgery, Johns Hopkins University, Baltimore, MD, United States

New method for quantifying the lung heterogeneity from the HP 3He MRI measurements of alveolar partial oxygen pressure pO2 is tested in this human study. The method allows us to differentiate healthy smokers and COPD patients from non-smokers based on the difference in their lung homogeneity.

Iga Muradyan¹, Mirko Hrovat², Mikayel Dabaghyan³, James Butler⁴, Hiroto Hatabu³, and Samuel Patz^3
1Brigham and Women's Hospital, Boston, MA, United States, ²Mirtech, Inc., ³Brigham and Women’s Hospital, ⁴Harvard School of Public Health

Breathing is accompanied with alveolar shape changes: at lower lung volumes alveoli are more spherical, while at higher lung volumes they assume more polyhedral shape. Such changes can affect the field homogeneity in the tissue due to air-tissue susceptibility difference. We hypothesized that lung volume will affect pulmonary T2* and measured it at 3 lung volumes: near RV, FRC and TLC. The signal behavior with TE suggested that T2* does not follow mono-exponential function and more sophisticated model is necessary for proper T2* estimation. The lung data suggests a small increase of T2* with lung volume.

Michael Völker¹, Felix Breuer¹, Philipp Ehses¹, Simon Michael Triphan¹, Martin Blaimer¹, and Peter Michael Jakob^1,2
1Research Center for Magnetic Resonance Bavaria (MRB), Würzburg, Bavaria, Germany, ²Department of Experimental Physics 5, University of Würzburg, Germany

A strategy for fast T2 relaxometry of the human lung is presented. Using radial TSE data acquisition, artifact-free separation of different T2 contrasts is possible by means of a novel iterative reconstruction technique based on Principal Component Analysis (PCA). It is shown that multislice T2 maps can be obtained in one single breathhold of 12s.

Wei-Min Tseng¹, Teng-Yi Huang¹, Yi-Ru Lin², and Ming-Ting Wu^3
1Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, ²Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, ³Department of Radiology, Kaohsiung Veterans General Hospital, Kao-Hsiung, Taiwan

This study attempts to accelerate pixel-by-pixel non-linear fitting with modern parallel computation on graphic processing units. Levenberg-Marquardt algorithm was implemented into GPU-based toolbox compatible to MATLAB environment. The time-intensity curve of each pixel is distributed to each thread of parallel computation. The four-GPU system can compute up to 960 curve-fitting in parallel. The toolbox was tested with a 7-slice pulmonary DCE perfusion dataset to reconstruct the pulmonary blood volume maps. The proposed GPU-fitting toolbox reduced the total computation time from ~20 minutes to ~0.5 minute.

Frank G Zoellner¹, Katrin Zahn², Thomas Schaible³, Stefan O Schoenberg⁴, Lothar R Schad¹, and K W Neff^4
1Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany, ²Dept. of Pediatric Surgery, University Medical Center Mannheim, Heidelberg University, Mannheim, ³Dept. of Pediatrics, University Medical Center Mannheim, Heidelberg University, Mannheim, ⁴Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany

In congenital diaphragmatic hernia (CDH), lung hypoplasia and secondary pulmonary hypertension are the major causes of death. To the best of our knowledge, quantitative perfusion imaging of the lung in CDH has not been utilized so far. Here, we investigated whether DCE-MRI of the lung in survivors after CDH-repair at 3.0T is feasible. Ipsilateral lung hypoplasia with reduced perfusion is reflected by significant lower rPBF values (34.3±18 ml/100ml/min) compared to the contralateral lung (89.7±27 ml/100ml/min). In conclusion, DCE-MRI of the lung in CDH can help characterizing lung hypoplasia initially and in long-term follow-up of children after CDH-repair.

Jens Vogel-Claussen^1,2, Jan Skrok², Monda Shehata², David A Bluemke³, Reda Girgis², and Paul M Hassoun^2
1Tübingen University, Tübingen, BW, Germany, ²Johns Hopkins University, Baltimore, MD, United States, ³National Institutes of Health

Predictors of survival in patients with pulmonary arterial hypertension (PAH) include right ventricular (RV) cardiac index (RVCI), mean pulmonary arterial pressure (mPAP), and pulmonary vascular resistance (PVR). Our hypothesis was that first-pass contrast bolus kinetics, such as cardiopulmonary transit time (PTT), left ventricular (LV) full-width-half-maximum (FWHM), and LV time-to-peak are related to these parameters. In our MRI study we showed that in patients with known or suspected PAH, first-pass bolus kinetics are closely related to pulmonary hemodynamics and RV dysfunction. Right-to-left-ventricular PTT is predicted by RV cardiac function and biventricular remodeling; time-to-peak and FWHM are associated with pulmonary vascular resistance.

Martin R Prince^1,2, Honglei Zhang¹, Zhitong Zou¹, Ronale B Staron², and Paula W Brill^1
1Radiology, Weill Cornell Medical College, New York, NY, United States, ²Radiology, Columbia College of Physicians and Surgeons, New York, NY, United States

GBCA adverse events reported in 94 patients over 10 years were analyzed to determine their incidence. Immediate AE rates were 0.2, 0.5, 1.2 and 3.3 per 1,000 injections for gadodiamide, gadopentetate dimeglumine, gadobenate dimeglumine and gadoteridol. Gadobenate dimeglumine had more severe reactions (3 arrests, one of whom died). Abdominal MRI had the highest rates of AE, 0.013% compared to brain (0.0045%) or spine (0.0034%). From 2004 to 2009 FDA received reports on 40 GBCA US deaths unrelated to NSF with an incidence of < 1 death per million (40 deaths/51 million GBCA administrations) indicating GBCA are extraordinarily safe.

Elise Eva Saddleton¹, Anne Laumann², Dennis P. West², Steven M. Belknap³, Brenda Schmitz¹, Beatrice J. Edwards³, Nicole Papariello², Michael I. Abecassis⁴, and Frank H. Miller^1
1Radiology, Northwestern University, Chicago, IL, United States, ²Dermatology, Northwestern University, Chicago, IL, United States, ³Medicine, Northwestern University, Chicago, IL, United States, ⁴Transplant Surgery, Northwestern University, Chicago, IL, United States

The FDA’s 2007 warning describing the risk of nephrogenic systemic fibrosis (NSF) with gadolinium administration in patients with acute renal insufficiency of any severity due to hepatorenal syndrome or in the perioperative liver transplantation period poses a significant problem for practitioners who routinely use magnetic resonance imaging (MRI) to evaluate liver transplant patients. The warning appears to have been based on a few patients who received gadodiamide. We evaluated the use of gadolinium-based contrast agents (GBCAs) and the presence of NSF in a large liver transplant center. We hypothesized no increased risk of NSF in the perioperative liver transplant period beyond that associated with severe renal disease.

Gianpaolo Pirovano¹, Cindy Schultz², John R Parker², Miles A Kirchin³, and Alberto Spinazzi^1
1Worldwide Medical Affairs, Bracco Diagnostics Inc., Princeton, NJ, United States, ²Medical Communications, Bracco Diagnostics Inc., Princeton, NJ, United States, ³Medical Communications, Bracco Imaging, Milan, Italy

Following a comprehensive literature search, 133 articles were identified, reporting 705 unique cases of NSF from 19 countries. 605 cases (85.8%) were biopsy-proven. Most cases involved patients with Stage 4 or 5 CKD, although in 14 cases the patient suffered from acute renal failure. Patients receiving only Omniscan or Magnevist accounted for 93.3% of reported NSF cases. The most commonly administered gadolinium doses were 0.2-0.29 mmol/kg. In most cases, symptoms appeared 1-3 months after the last administration of gadolinium contrast. Importantly, no cases with an onset after 2007 were identified, suggesting changes in practice patterns have largely eliminated this disease.

Valeria Righi^1,2, Melissa Starkey³, Jianxin He³, George Dai², Vitaliano Tugnoli⁴, Laurence G. Rahme³, Ronald G. Tompkins⁵, and Aria A. Tzika^1,2
1Department of Surgery, NMR Surgical Laboratory, MGH and Shriners Burn Institute, Harvard Medical School, Boston, MA, United States, ²Department of Radiology, Athinoula A. Martinos Center of Biomedical Imaging, Boston, MA, United States, ³Department of Surgery, Molecular Surgery Laboratory, MGH and Shriners Burn Institute, Harvard Medical School, Boston, MA, United States,⁴Departement of Biochemistry, University of Bologna, Bologna, Bologna, Italy, ⁵Department of Surgery, MGH and Shriners Burn Institute, Harvard Medical School, Boston, MA, United States

We demonstrated the feasibility to monitor inhibition of infection in a clinically relevant mouse model of infection after burn. Our results show that our novel compound M50 attenuates the signals coming from macrophages that accumulate at the infection site and thus support the compound’s anti-infective action. These results may have direct implications in the longitudinal monitoring of infection, and open perspectives for testing our novel anti-virulence compounds.

Jihong Sun^1,2, Weiliang Zheng¹, Hong Yuan³, Tao Wu¹, Xiaoming Yang^1,2, and Shizheng Zhang^1
1Radiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China, People's Republic of, ²Radiology, University of Washington School of Medicine, Seattle, WA, United States,³College of Pharmaceutical Science, Zhejiang University, Hangzhou, Zhejiang, China, People's Republic of

The aim of this study was to develop a novel nanoparticle-based magnetic resonance (MR) colonography technique, which enabled us to generate contrast-enhanced MRI of the colonic walls via transrectal administration of colonic-absorbable, Gd-DTPA-loaded solid lipid nanoparticles (SLNs). In vivo MRI demonstrated bright enhancement of colonic walls with decreased T1 relaxation times in all mice treated by transrectal infusions of Gd-SLNs, which was confirmed by subsequent histologic correlation. This study establishes the ¡°proofs-of-principle¡± of a new imaging technique ©¤ nanoparticle-based MR colonography.

Kiterie Maud Faller¹, Craig A Lygate¹, Stefan Neubauer¹, and Jurgen E Schneider^1
1Cardiovascular medicine, University of Oxford, Oxford, Oxfordshire, United Kingdom

Creatine has a protective effect against ischemia in tissues with high energy demand such as the brain or the heart. ¹H-MRS is the only technique available to measure creatine non-invasively. As the metabolism of creatine is organ-specific, spectra from different organs need to be acquired to get a general view of creatine metabolism in the mouse. We showed that creatine can be measured within a single anaesthesia in three different organs (brain, cardiac and skeletal muscles) with a simple set-up and with a good accuracy. This allows us to perform longitudinal studies in mice with global changes in creatine levels.

Yunjung Lee¹, Hyungjoon Noh¹, Keunhyung Kang¹, Ok-Hee Kim¹, Byung-Chul Oh¹, and Hyeonjin Kim^2
1Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon, Korea, Republic of, ²Radiology, Seoul National University Hospital, Seoul, Korea, Republic of

Liver fibrosis was characterized in CCl4-treated rats by using both 1H- and 31P-MRS, and the potential diagnostic efficacy of the technique was evaluated. The differentiation between the three animal groups of control, F1-2 and F3-4 in this study was achieved only if the combination of the 1H- and 31P-MRS measures was used. Therefore, our study demonstrates the advantage and feasibility of using both 1H- and 31P-MRS techniques in the assessment of liver fibrosis in vivo.

Toshihiro Furuta^1,2, Masayuki Yamaguchi¹, Ryutaro Nakagami^1,3, Masaaki Akahane², Manabu Minami⁴, Kuni Ohtomo², and Hirofumi Fujii^1
1Functional Imaging Division, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Japan, ²Department of Radiology, The University of Tokyo Hospital, Tokyo, Japan, ³Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan, ⁴Department of Radiology, Tsukuba University Hospital, Tsukuba, Japan

We propose a new technique for the detection of liver damage based on the impaired exocytotic activity of Kupffer cells (KCs) using SPIO-enhanced MRI, in which SPIO was administered in advance of the liver damage. Our hypothesis is that if KCs are labeled with SPIO prior to liver damage, the exocytotic activity of KCs could be evaluated by the delayed recovery of hepatic signals suppressed by SPIO on T₂^*-weighted MRI. Our preliminary data using an animal model, in which KCs were damaged by the administration of gadolinium chloride, supported our hypothesis.

Andrew G. Taylor¹, Kayvan Keshari¹, Robert Bok¹, Subramaniam Sukumar¹, Aliya Qayyum¹, and John Kurhanewicz^1
1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States

Non-Alcoholic Fatty Liver Disease (NAFLD) is a very common cause of chronic liver disease, however understanding of metabolic abnormalities and prognostic indicators in NAFLD is limited. In vivo studies of hepatic metabolism in a mouse model of NAFLD were performed at 600MHz using copolarized [1-13C]-pyruvate and 13C-urea. An interleaved fat- and water-sensitive sequence, used to monitor disease progression, correlated well with extent of steatosis on subsequent histology. No significant change in hepatic pyruvate metabolism was identified in NAFLD mice relative to control, consistent with published work suggesting hypermetabolism in this model results from increased lipid flux through β-oxidation.

Mike Notohamiprodjo¹, Michael Pedersen², Christian Glaser^3,4, Andreas D Helck³, Klaus-Peter Lodemann⁵, Bente Jespersen⁶, Michael Fischereder⁷, Maximilian F Reiser³, and Steven P Sourbron^8
1Department of Clinical Radiology, University Hospitals Munich, Munich, Bavaria, Germany, ²MR Research Centre, Aarhus University Hospital, ³Department of Clinical Radiology, University Hospitals Munich, ⁴Department of Radiology, NYU Langone Medical Center, ⁵Bracco Imaging Germany, ⁶Department of Nephrology, Aarhus University Hospital, ⁷Department of Nephrology, University Hospitals Munich, ⁸Division of Medical Physics, University of Leeds

Protein binding of MR contrast agents may cause a systematic error in perfusion- and filtration parameters measured with MR-Renography. The purpose of this study was to measure the magnitude of this error using a dual-agent protocol in a pig model. The findings of the performed experiments show that perfusion parameters of both agents are comparable, whereas GFR is underestimated with Gd-BOPTA due to the dependence of relaxivity on protein content. Hence GFR cannot be measured with protein-bound contrast agents, but the proposed dual-agent protocol may produce new functional indices measuring protein filtration.

Muhammad E Haque¹, Tammy Franklin¹, Ujala Bokhary¹, Liby Mathew², Anthony Chang³, Tipu Puri², and Pottumarthi V Prasad^1,4
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, ²Nephrology, University of Chicago, Chicago, IL, ³Pathology, University of Chicago, Chicago, IL, ⁴Radiology, University of Chicago, Chicago, IL, United States

Current clinical markers to assess the severity of chronic kidney disease (CKD) and its progression are limited and inadequate. It is highly desirable to develop new non-invasive markers that could reliably monitor the progression of disease over time. Renal hypoxia and fibrosis are two known hallmarks of CKD. Here we have used a reversible unilateral ureteral obstruction model in mice to evaluate BOLD and diffusion MRI measurements to monitor progression of CKD We also evaluated genetic variability between two strains of mice. These methods may prove valuable in better understanding the natural progression of CKD and in evaluating novel interventions.

Andreas Pohlmann¹, Lajos Marko^2,3, Babette Wagenhaus¹, Uwe Hoff⁴, Erdmann Seeliger⁵, Dominik N Mueller^2,3, and Thoralf Niendorf^1
1Berlin Ultrahigh Field Facility, Max Delbrueck Center for Molecular Medicine, Berlin, Germany, ²Max Delbrueck Center for Molecular Medicine, Berlin, Germany, ³Experimental and Clinical Research Center, Charité University Medicine, Berlin, Germany, ⁴Clinic for Nephrology, Charité University Medicine, Berlin, Germany, ⁵Institute of Vegetative Physiology, Charité University Medicine, Berlin, Germany

Renal medullary hypoperfusion and hypoxia play a key role in acute kidney injury (AKI). Established methods to assess renal hemodynamics and oxygenation in vivo are limited to short time periods and/or probing only small regions. MRI allows assessing tissue oxygenation and oedema for the entire kidneys, repeatedly. We demonstrated the feasibility of characterizing alterations in renal hemodynamics and oxygenation under (patho)physiological conditions such as renal ischemia/reperfusion injury (I-R). Kidneys that underwent I-R showed strong changes of contrast (T2w) in the cortex and medulla. T2*-mapping showed equally dramatic changes quantitatively.

Amir Moussavi¹, Martin Uecker¹, Tilman Johannes Sumpf¹, Roland Tammer^1,2, Jens Frahm¹, and Susann Boretius^1
1Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut fuer biophysikalische Chemie, Goettingen, Germany, ²DFG Research Center for Molecular Biology of the Brain (CMPB), Goettingen, Germany

To avoid the necessity of respiratory gating, abdominal MRI of the mouse requires short acquisition times. The combination of highly undersampled radial FLASH with a nonlinear inverse image reconstruction algorithm allowed for movies with a temporal resolution of 70 ms per image. Accordingly, dynamic contrast-enhanced studies of the mouse kidney could be performed at high spatial and temporal resolution. Moreover, the approach facilitated the simultaneous coverage of both kidneys by multiple sections.