Self-Navigated Multi-Contrast And Quantitative Whole Heart 3D Magnetic Resonance Imaging

Cardiovascular disease (CVD) remains the leading single cause of death worldwide despite improvements in prevention and advances in diagnosis and treatment. The two major causes for CVD death are sudden coronary atherothrombosis due to plaque rupture and subsequent thrombus formation and heart failure following myocardial infarction (MI) due to adverse myocardial remodeling and subsequent infarct expansion. Detection of coronary atherosclerosis and prediction of adverse myocardial remodeling remain challenging with current imaging techniques. While x-ray coronary angiography is the gold standard for the detection of coronary stenosis it has limited value for the detection and characterization of coronary plaque. Multislice computed tomography (MSCT) is an excellent non-invasive alternative for the detection of coronary stenosis and has some ability to visualize and characterize coronary plaque but its diagnostic use is limited to patients without coronary calcification. Positron electron tomography (PET) has good diagnostic sensitivity for myocardial perfusion and viability assessment and recently also has been shown to have potential for coronary plaque visualization but suffers from low spatial resolution and radiation exposure and is not widely available. Echocardiography is the clinical gold standard for the assessment of left ventricular function and wall motion abnormalities. It is cheap and easy to use but is heavily operator dependent. Due to the above limitations there is a need for the development of an alternative and non-invasive imaging test that allows for comprehensive cardiac assessment without the above restrictions.

Magnetic resonance imaging (MRI) is considered the gold standard for the assessment of cardiac anatomy, left ventricular (LF) function (CINE-MRI), myocardial viability (LGE-MRI) and perfusion (MR-perfusion) due to its excellent soft tissue contrast, high spatial resolution and lack of ionizing radiation according to a Society for Magnetic Resonance (SCMR) expert consensus statement. Recent clinical research studies also have demonstrated its usefulness for quantitative myocardial tissue characterization (T1 and T2 relaxation time mapping) and its ability to differentiate between healthy and diseased tissue. However, a key limitation of the current MRI acquisition scheme is that all imaging sequences (e.g. CINE, LGE, T1 and T2 mapping, coronary MR angiography (MRA), etc.) are acquired sequentially, in different geometric orientations, at different breath-hold positions or using time inefficient navigator gating methods. This imposes several challenges: (1) radiographers need high expertise to perform the complex examination, (2) patients have to perform multiple (>30) breathholds which can be very challenging in sick patients, (3) the duration of the examination is long leading to high operational costs and (4) data fusion is difficult because of the different breathhold positions, scan geometries and non-isotropic spatial resolution. We hypothesize that image based respiratory self-navigation combined with image acceleration techniques will address the above challenges and allow improving the reliability and image quality of free-breathing (no breathholds) three-dimensional (3D) multi-contrast quantitative whole heart cardiac MRI. The proposed approach will enable non-invasive comprehensive cardiac examination with improved patient experience, higher diagnostic yield and improved cost effectiveness thereby improving the treatment and outcome of cardiovascular disease as outlined by the NHS white paper.

Our goal is to maximise the impact of our work through dissemination of our ideas and results to the academic and clinical communities and potential industrial partners. The scientific methodology results from this research will be output as research publications in high-impact journals in the field of medical imaging and cardiology. Target journals will include Magnetic Resonance in Medicine, Circulation and Radiology. Dissemination will also take place through presentations at the major international academic conferences, especially the International Society for Magnetic Resonance in Medicine (ISMRM) and the Society for Cardiovascular Magnetic Resonance (SCMR).

A large amount of phantom and in-vivo cardiac MR data will be generated during the lifetime of this grant. We will protect any resulting intellectual property in consultation with KCL Enterprises. After the studies are published in scientific journals, and after they are patented if patenting is a viable option, this data will be made publicly available for research use. After completion of the project we also plan to share the developed software with other MR researchers and clinicians interested in our methods in order to validate the developed imaging methods at other medical centres and/or to further improve the methodology. Moreover, we will work closely with the manufactures to develop works in progress packages that can be easily shared with other universities or medical centres and that will also allow rapid translation of the developed methods into commercial products of the vendors. This will facilitate wider spread clinical use of this research and enhance the clinical impact of this research. The Division has a Master Research Agreement both with Philips and Siemens providing access to acquisition and reconstruction source code. Philips is currently funding, through our new EPSRC Centre for Doctoral Training (CDT) in Medical Imaging at KCL/Imperial College, one PhD student working on motion corrected 3D T1 mapping under the supervision of the PI, which is relevant to this project. Throughout the project we will post blogs about our latest results on the Division's blog (https://kingsimaging.wordpress.com/) to reach a larger community and to make our research results more accessible to a larger community. In addition, we will participate in the "Pint of Science" 3-day annual festival and present our research results in pubs around London to engage with local communities. We also plan to present to the Public and Patient Involvement Cardiovascular group at Guy's and St Thomas' Hospital to provide updates and receive patient feedback (http://www.guysandstthomasbrc.nihr.ac.uk/PatientsPublic/Getinvolved/Haveyoursay/Cardiovascular.aspx).