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

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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.