Is your heart beating correctly?: pulmonary vein imaging using magnetic resonance
As long as we are alive is our heart beating normally? Can the interaction of water molecules and magnets be used to visualise heart function? What implications does this have in assessing and treating irregular heartbeats? The most prevalent irregular heartbeat, atrial fibrillation, has been diagnosed in 20 million people worldwide and originates in the left atrium and pulmonary veins of the heart. Improved visualisation of this region, would vastly improve individualised patient care. Magnetic resonance imaging (MRI) utilises hydrogen from water within the body to image internal organs. Hydrogen molecules constantly rotate however, applying magnetic fields and radiofrequency energy can manipulate them to release a signal, which is used to generate images. Short movies are made using cine MRI, showing the pumping movement of the heart that allows blood flow. Acquisition time of cardiac images is limited, as patients must hold their breath to restrict chest motion. Whilst flowing through the lungs hydrogen molecules in blood rotate faster or slower and enter the heart through the pulmonary veins in this off-resonance state. An MRI scanner is not optimised to receive signal from off-resonant hydrogen therefore, dark regions appear in images where the pulmonary veins should be visible. My research aims to overcome this by acquiring multiple image sets, applying the magnetic fields differently in each. Addition of these image sets improved pulmonary vein detection by 60% across nine human subject trials and is proposed with innovations permitting only a 3 second increase in breath-hold. A three-dimensional version of this technique would provide capabilities in modelling patient’s organs for use in surgical planning.
I am a biomedical engineering student in the final year of my MEng program. I was delighted to discover a path of education that would excite, challenge and intertwine my interest in biology, physics and maths as well as implement my creative side. Furthermore, career prospects in helping people and bettering lives through medical innovation sealed the deal. Over the course of my studies I became enthralled by the world of medical imaging, using the fundamental concepts of physics to image anatomy and biological function revolutionised and continues to advance modern healthcare. During the first semester of my fifth year I undertook a research placement at the Magnetic Resonance Research Centre at Yale University in Connecticut. I worked on improving methods of image acquisition and reconstruction for more effective diagnosis and treatment planning. This experience inspired my desire to build a career that bridges research, commercial development and clinical implementation.