PULMONARY GAS FLOW MEASUREMENT USING [3]HE MRI

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The goals of this protocol are to develop a method of quantifying pulmonary gas flow using inhalation of helium3 and dynamic MRI. This is a developmental study. Volunteers will be imaged by 3HeMRI. 3HeMRI is a radical new method of lung imaging that promises high spatial resolution assessments of lung function that are unavailable by any other technique. With this test the lung airspaces and airways are directly visualized by inhaling the hyperpolarized gas and forming MRI images. Subjects will be instructed to breathe deeply four times and on the final inhalation the 3He will be administered. The investigators believe that the smallest possible volume of inhaled gas, followed by a "chaser" of air, will give the best results. The 3He will not be diluted with nitrogen. The investigators will try doses of 100, 200 and 300 ml of 3He to determine whether the higher signal to noise offered by the greater quantity of gas compensated for the longer bolus. This will be assessed by measuring the signal to noise in calculated flow and volume measurements in the larger vessels. The main focus of the proposal is to develop quantitative methods to analyze the data, based on algorithms designed to evaluate blood flow. The investigators have an approved IND and intend to study 20 normal volunteers. This is a pilot study of what could turn out to be a simple, non-invasive way to examine pulmonary gas flow.