Cardiovascular Applications of Magnetic Resonance Imaging

Abstract

Cardiovascular diseases are the leading cause of death in the Netherlands. By the year 2030 it will be the leading cause of death in all parts of the world, including third world countries. Therefore, it is essential to improve diagnostic tools and continue research into the development of these diseases. Two themes are addressed in this thesis: magnetic resonance imaging (MRI) of atherosclerosis and cardiac imaging in heart failure and myocardial infarcts. In the first part of this thesis research has been focused on the evaluation of new MRI contrast agents in mice to identify atherosclerotic lesions which are at risk to cause serious events. The dangerous, rupture-prone atherosclerotic plaques can cause heart attacks or strokes. When these rupture-prone atherosclerotic plaques are located and identified in an early phase patients can be treated earlier and events might be prevented. In an additional study we worked at the identification of different components which are present in atherosclerotic plaques in the carotid arteries in humans. With the 7 Tesla MRI scanner it is possible to image the brain and atherosclerotic plaque in a high resolution. Hopefully, this 7 Tesla MRI scanner can be used to identify rupture-prone atherosclerotic lesions in carotid arteries without the need of contrast agents. In the second part of this thesis research was performed in mice which suffered from a myocardial infarction or diastolic heart failure. First a new method was evaluated to perform cardiac function measurements with MRI in small rodents. This self-gating method makes the need for ECG-electrodes obsolete and therefore gives more reliable and faster results. Cardiac function assessment in mice is used to determine effectiveness of new medications and could lead to new or improved treatments in patients in the future. In a different study we studied heart failure, diastolic failure in diabetic mice. Patients suffering from diabetes can develop disturbed ventricular filling patterns, diastolic heart failure. Diastolic heart failure may lead to systolic heart failure and pulmonary edema, however in the early phase no clinical symptoms are present. The early detection of diastolic heart failure is essential to start treatment early on and prevent further deterioration of cardiac function. The study showed that in diabetic mice early detection of diastolic failure was possible with a high temporal resolution MRI scan, even before the mice developed systolic heart failure and cardiac hypertrophy.