Development of MRI scan methods to image inhaled fluorocarbon gases as biomarkers of lung structure and function.

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The aim of this project is to develop new magnetic resonance imaging (MRI) methods to measure lung functional and structural properties. We will image the distribution within the lung of perfluoropropane - an inert, inhalable gas that can be visualised with 19F-MRI: an MRI scan that detects the fluorine nuclei within inhaled perfluoropropane gas. We will implement and test new MRI scanner hardware and scan acquisition methods to improve the image quality of lung scans made with this method, and use accelerate scan methods to improve scan tolerability for patients with respiratory disorders. Whilst there are methods to assess lung structural and functional properties in current clinical practice, these either lack spatial information (and so don't detect subtle localised changes associated with early respiratory disease) or use ionising radiation that carries a risk to the patient. MRI offers a safely repeatable and radiation-free imaging method and our approach to lung imaging permits quantitative measurement of lung ventilation properties than is sensitive to respiratory disease.The novel healthcare technologies developed in this project will underpin the downstream use of lung 19F-MRI clinical research and clinical practice.Project objectivesThe key objectives of this study are to measure the impact of MRI acceleration methods on 19F-MRI measures of lung ventilation properties, and to employ accelerated 19F-MRI methods in the development of lung functional and structural measurements than can ultimately be applied in clinical research and clinical practice. We hypothesise that a combination of advanced acceleration techniques can deliver a marked improvement in scan resolution and reduced scan duration, which in turn can improve ability to quantify ventilation defects in patients with respiratory disease and deliver better and more patient-friendly scan methods (such as free-breathing rather than breath-held scanning).MRI scan acceleration methods are well established for conventional clinical MRI scanning. Acceleration methods such as parallel imaging and compressed sensing are available as products from all major MRI scanner manufacturers, however their use in multinuclear MRI (such as 19F-MRI of inhaled perfluoropropane) is not widespread or easily implemented on a standard clinical scanner. We recognise that existing lung 19F-MRI methods have not yet fully exploited the capabilities provided by scan acceleration methods, and we see scope for significant improvement of image quality for lung 19F-MRI beyond the current state of the art. Our studies will use lung-mimicking test objects and studies of healthy volunteers to test new MRI scanner sensor (RF coil) hardware and scanner software (MRI pulse sequences). We will combine parallel imaging and compresses sensing to produce more detailed (higher resolution) 3D images of lung ventilation properties and advance from static lung images to dynamic (movie) 3D images that show the wash-in and wash-out of our tracer gases throughout the lungs. The new imaging technologies developed in this project will then be positioned for immediate use in clinical research studies that assess the progression of respiratory diseases, and that assess the effects of therapeutic strategies (e.g. novel drug treatments) on lung function, and the imaging methods have potential for development towards the ultimate goal of use in clinical practice for respiratory disease diagnosis and monitoring.