Arguably the biggest gap preventing progress in treating chronic pulmonary diseases is the lack of a sufficiently sensitive, comprehensive, and non-invasive means to evaluate lung function. Until this gap is filled, patients will receive medications that don't work for them, and development of new therapies will remain expensive, slow, and largely unsuccessful. The long-term goal of our research, therefore, is to develop and implement a means to image all relevant aspects of cardiopulmonary function and structure, non-invasively and longitudinally. Our approach uses hyperpolarized (HP) 129Xe MRI to image ventilation, microstructure, and gas exchange. The objective of this application is to optimize our recently demonstrated capability to image regional gas exchange by 129Xe MRI in human subjects, to use the optimized method to measure and understand resting perfusion heterogeneity, and to demonstrate the sensitivity of this imaging approach to detect changes regional lung function much earlier than currently possible. The central hypothesis is that regional gas exchange is the most sensitive marker of early changes in pulmonary function compared to available means. The rationale for the proposed research is that developing a method that can non-invasively evaluate regional gas exchange will dramatically accelerate research in pulmonary medicine by providing a more sensitive and specific measurement that can be used repeatedly. Thus, the proposed research is relevant to that part of the NIH Mission that pertains to improving health by developing and accelerating the application of biomedical technologies. Guided by strong preliminary data, the central hypothesis will be tested by pursuing three Specific Aims: 1) Optimize 3D blood-selective 129Xe gas exchange MRI 2) Establish image reproducibility as a function of time, posture, and cardiac output, and 3) Image the temporal evolution of regional gas exchange during radiation therapy. Completion of these aims will establish the utility, sensitivity and limitations of this new method compared to gold standards, while positioning it as a sensitive biomarker for research in pulmonary medicine.
The first aim i s expected to improve the current gas exchange image resolution 8-fold, add specificity for fibrosis, and establish the key MR physics governing the acquisition.
The second aim will uncover the key determinants of the resting heterogeneity of 129Xe gas exchange already observed in preliminary studies and establish their reproducibility.
The final aim brings these technical and developmental insights together to test the hypothesis that 129Xe MRI will detect alterations in gas exchange earlier than currently available means. The proposed approach is innovative because it exploits the unique properties of HP 129Xe MRI and an innovative acquisition to image lungs'most fundamental function - gas exchange. The proposed research is significant because the imaging method being developed is expected to provide a long-sought window on gas transfer into the pulmonary microcirculation as a harbinger of changing disease status.

Public Health Relevance

The proposed studies will optimize and test a non-invasive imaging technique to evaluate the gas exchange in the lung on a regional basis. Such images could greatly enhance the sensitivity for detecting early lung disease and allow earlier determination of whether a particular therapy is improving a patient's lung function. The proposed research has relevance to public health because new tools for non-invasively evaluating lung function will not only improve patient outcomes, but will accelerate research to develop better therapies.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL105643-04
Application #
8588346
Study Section
Medical Imaging Study Section (MEDI)
Program Officer
Gan, Weiniu
Project Start
2011-02-01
Project End
2015-11-30
Budget Start
2013-12-01
Budget End
2014-11-30
Support Year
4
Fiscal Year
2014
Total Cost
$348,533
Indirect Cost
$123,533
Name
Duke University
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
He, Mu; Kaushik, S Sivaram; Robertson, Scott H et al. (2014) Extending semiautomatic ventilation defect analysis for hyperpolarized (129)Xe ventilation MRI. Acad Radiol 21:1530-41
Freeman, M S; Emami, K; Driehuys, B (2014) Characterizing and modeling the efficiency limits in large-scale production of hyperpolarized (129)Xe. Phys Rev A 90:023406
Kaushik, S Sivaram; Freeman, Matthew S; Yoon, Suk W et al. (2014) Measuring diffusion limitation with a perfusion-limited gas--hyperpolarized 129Xe gas-transfer spectroscopy in patients with idiopathic pulmonary fibrosis. J Appl Physiol (1985) 117:577-85
Cleveland, Zackary I; Virgincar, Rohan S; Qi, Yi et al. (2014) 3D MRI of impaired hyperpolarized 129Xe uptake in a rat model of pulmonary fibrosis. NMR Biomed 27:1502-14
Kaushik, S Sivaram; Freeman, Matthew S; Cleveland, Zackary I et al. (2013) Probing the regional distribution of pulmonary gas exchange through single-breath gas- and dissolved-phase 129Xe MR imaging. J Appl Physiol (1985) 115:850-60
Freeman, Matthew S; Cleveland, Zackary I; Qi, Yi et al. (2013) Enabling hyperpolarized (129) Xe MR spectroscopy and imaging of pulmonary gas transfer to the red blood cells in transgenic mice expressing human hemoglobin. Magn Reson Med 70:1192-9
Driehuys, Bastiaan; Martinez-Jimenez, Santiago; Cleveland, Zackary I et al. (2012) Chronic obstructive pulmonary disease: safety and tolerability of hyperpolarized 129Xe MR imaging in healthy volunteers and patients. Radiology 262:279-89