Background Coronary Allograft Vasculopathy (CAV) is the leading cause of late death for children after heart transplantation. It often presents late due to lack of ischaemic symptoms from the denervated allograft and it is difficult to detect using conventional angiography. A non-invasive diagnostic tool would be invaluable for the early detection and therefore, prevention of disease. MRI has the potential to achieve this by imaging coronary lumen, vessel wall and central vascular stiffness in a child-friendly free-breathing protocol lasting thirty minutes. Methods A three-dimensional steady-state-free-precession [3D SSFP) imaging sequence for coronary artery lumen imaging was optimised for its use in children. Patient based studies were performed to show the clinical potential for this approach. Furthermore, contrast-enhanced inversion-prepared coronary vessel wall imaging was investigated for its ability to detect intimal disease in CAV, using intravascular ultrasound to validate the findings. Finally, MRI was used to study the potential of aortic screening for rapid assessment of CAV.Results MRI coronary artery lumen imaging is feasible in children and reference values are provided. Contrast-enhanced vessel wall imaging has 91% accuracy in the detection of significant CAV. Further improvements in the technique can be achieved using high-field MRI (3.0 Tesla) or sublingual nitroglycerin. Central aortic stiffness is increased in children after heart transplantation and a relationship between this and CAV is demonstrated. Conclusions Coronary artery lumen and vessel wall MRI can be used to follow up children after heart transplantation. Non-invasive follow-up can be more frequent and has the potential to allow early prevention. From this research, there are wider implications for congenital heart disease, Kawasaki disease and cardiovascular atherosclerosis imaging.
|Date of Award
|1 May 2013
|Gerald Greil (Supervisor) & Rene Botnar (Supervisor)