Multidimensional and Multiparametric Quantitative Cardiac MRI from Continuous Free-Breathing Acquisition

Cardiovascular disease (CVD) is the leading single cause of morbidity and mortality in the Western world, causing over 65.000 deaths every year in England. Improving the treatment and outcome of cardiovascular disease is one of the main priorities of the National Health Service (NHS) and a reduction of 25% in mortality associated to cardiovascular disease by the year 2025 is one of the major challenges proposed by the United Nations. Magnetic Resonance Imaging (MRI) is a very promising non-invasive tool for early risk assessment, guidance of therapy and treatment monitoring of CVD. MRI has been shown to provide exquisite depiction of cardiac anatomy and is considered the gold standard to assess ventricular volumes and function. More recently, quantitative mapping of magnetic relaxation properties (known as e.g. T1 and T2 relaxation times) have been developed to standardise the quantitative measurement of myocardial tissue properties, enabling non-invasive characterisation and differentiation of diseased and healthy tissue. Clinical research studies have shown the potential of parametric mapping techniques for quantification of diffuse myocardial fibrosis (T1 map) and the assessment of myocardial oedema and inflammation (T2 map). Thus, MR parameter mapping offer the promise of early disease detection and monitoring over time or in response to therapy, changing the MR paradigm from visualisation to quantification.

The limitation of the current MRI scheme is that all these images (e.g. cardiac anatomy, function, T1 map and T2 map) are acquired sequentially, usually with different resolution, different geometric orientations and at different breath-hold positions. This scheme requires patient cooperation as acquisitions are usually performed under multiple breath holds, requires experienced radiographers to plan and perform the different acquisitions, and results in long scan times. Moreover patients are usually unable to hold their breath at the same respiratory position. Thus images acquired at different breath-holds cannot be directly fused thereby affecting diagnosis, accuracy and reproducibility of cardiac MRI.

The method proposed in this project will overcome these problems by allowing the simultaneous acquisition of MR images with multiple parameters (e.g. cardiac anatomy, function, T1 map and T2 map), throughout the whole cardiac and respiratory cycles, from a single free-breathing acquisition. Thus providing anatomic and functional information simultaneously with quantitative information of multiple tissue parameters for an efficient (single scan, shorter and predictable scan time), accurate, simplified (less planning required and more comfortable for the patients) and comprehensive assessment of cardiovascular disease.

The beneficiaries of this research will be patients with cardiovascular disease (CVD), who will benefit from an efficient, accurate and more comfortable non-invasive diagnostic test. Secondary beneficiaries will be clinicians involved in the diagnosis and treatment of CVD. Complementary and co-registered information provided by both qualitative and quantitative cardiac MR images will enable more reliable diagnosis. In the long term this project will also help reducing NHS healthcare costs by a) reducing planning and scan times, therefore decreasing the exam cost per patient; and b) improving hospital discharge rates by providing more accurate diagnosis. Moreover the technology developed in this project may also have an impact on other applications such as abdominal and liver imaging where accurate quantification and respiratory motion are known major challenges. Through commercialisation, the research will be of benefit to the imaging manufacturers and subsequently to the healthcare system by improving patient management through improved treatment outcome and reduced healthcare costs on a national and international level.

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. Results of the proposed research will be also presented to the Cardiovascular Patient and Public Involvement group at St Thomas' Hospital as well as to the general public in engagement activities such as Pint of Science and Healthcare Science Week. Throughout the project we will also 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. A large amount of phantom and in-vivo data will be generated during the lifetime of the grant. 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. Moreover the data and reconstruction codes generated during the lifetime of the grant will be used in different teaching, and networking activities. At the completion of this project we plan to work closely together with industrial partners to transfer the developed methodology into their product software to allow wide spread clinical use of this research.