Quantitative Dynamic Contrast Enhanced Magnetic Resonance Imaging for Evaluation of the Myocardium in Ischaemic Heart Disease

Background: Use of contrast enhanced cardiac magnetic resonance imaging (MRI) for identification of focal pathology (perfusion deficit and scar) is widespread. Quantitative analysis of dynamic contrast enhanced (DCE) MRI data may allow objective assessment of focal and diffuse disease. However it is a complex process and not widely adopted outside the research domain. For accurate quantification temporal variation in relative contrast agent concentration in the myocardium and feeding blood supply must be measured. While MRI signal intensity can be used as a probe of contrast agent concentration its response is non-linear.
Aims: In this thesis non-linearity correction methods for quantitative myocardial DCE-MRI are compared, the feasibility of a novel bookend T1 based correction is tested and the method is used in clinical studies to assess myocardial characteristics in health and ischaemic disease.
Methods: Signal non-linearity correction methods were compared using simulation, phantom experiments and a volunteer study. Methods compared were independent sampling strategies (dual-bolus and dual-sequence), previously proposed model based correction (native T1 or proton density weighted image based) and bookend T1 based correction which is proposed as a method to account for imperfect magnetisation preparation. The feasibility of the bookend T1 method was tested and characteristics of heathy and diseased myocardium were assessed in clinical studies of ischaemia and infarction.
Conclusions: Native T1 based correction has been found to be highly sensitive to imperfect magnetisation preparation, and is thus recommended against. Model based correction using proton density weighted images or bookend T1 data have been found to be more accurate and precise than dual-sampling methods. The clinical studies have demonstrated the feasibility of the bookend T1 based method and have yielded insights into myocardial characteristics in a range of conditions.