This thesis contains the results of imaging of adult zebrafish by using different MR approaches. We present the first high resolution mMR images of adult zebrafish. To achieve high spatial... Show moreThis thesis contains the results of imaging of adult zebrafish by using different MR approaches. We present the first high resolution mMR images of adult zebrafish. To achieve high spatial resolution we used a magnetic field of 9.4T, in combination with strong magnetic field gradients (1000 mT/m) and specialized radio frequency coils. To support imaging of living fish, we designed a special flow-through setup for continuous flow of aerated water to support living zebrafish inside the magnet. Clear morphological proton images were obtained by T2-weighted RARE sequences revealing many anatomical details in the entire intact zebrafish in vivo. We successfully implemented MRS at 9.4T and obtained for the first time detailed composition of zebrafish brain in vivo. Our results in this thesis suggest that zebrafish brain has similar metabolite profile as the human brain, which proves that zebrafish is a go od model organism to study human brain disorders. This thesis demonstrates also the application of high resolution mMRI methods to track spontaneous tumors in stable transgenic zebrafish models expressing a RAS oncoprotein and lacking P53 (mitf:Ras::mitf:GFP X p53-/-). Tumors were successfully visualized at different locations in live zebrafish. Show less
The aim of this thesis was to explore the relation between visceral obesity and the accompanying metabolic disturbances, systemic inflammation and the atherosclerotic process. A newly developed... Show moreThe aim of this thesis was to explore the relation between visceral obesity and the accompanying metabolic disturbances, systemic inflammation and the atherosclerotic process. A newly developed magnetic resonance vessel wall imaging technique was implemented in phenotyping patients and as a therapeutic endpoint in a randomised controlled setting. A three step approach was chosen for this purpose. First, the magnetic resonance black blood vessel wall imaging technique at the magnetic field strength of 3 Tesla was developed and validated. Secondly, phenotyping of viscerally obese subjects was performed with special attention for the role of systemic inflammation and atherosclerosis. Finally, in the setting of a randomised controlled trial, the impact of reducing visceral obesity and systemic inflammation with lifestyle intervention and rosiglitazone treatment (PPARg agonist) on the progression of atherosclerosis was assessed. Show less
The main objective of the current thesis is to assess aortic wall elasticity and aortic dimensions and their impact on aortic valve competence and LV function in patients with a bicuspid aortic... Show moreThe main objective of the current thesis is to assess aortic wall elasticity and aortic dimensions and their impact on aortic valve competence and LV function in patients with a bicuspid aortic valve, transposition of the great arteries, tetralogy of Fallot and patients after the Ross procedure, with the use of MRI. In addition, MRI was also used to test whether a similar interaction is present between pulmonary artery dynamics and the right ventricle in the above mentioned entities. Chapter 2 reviews the 5 most common entities of inherited connective tissue disorders and classical congenital heart disease with intrinsic aortic wall abnormalities, with description of the potential role of MRI in their evaluation and management. Chapter 3 describes in vivo validation, as well as testing of reproducibility of aortic pulse wave velocity as assessed with MRI, as indicator of aortic elasticity. Chapter 4 studies aortic elasticity, aortic valve competence and LV function in non-stenotic bicuspid aortic valve patients. Chapters 5 and 6 describe aortic elasticity, aortic valve competence and LV function, and the results of pulmonary flow dynamics in relationship with right ventricular function in patients after the arterial switch operation, respectively. Chapter 7 addresses aortic dimensions and elasticity in conjunction with aortic valve and LV function in patients with repaired tetralogy of Fallot after pulmonary valve replacement. Chapter 8 describes the outcome of patients who have previously undergone the Ross procedure in our institution for a dysfunctioning aortic valve. Chapter 9 studies aortic elasticity, aortic valve competence and LV function in patients after the Ross procedure. Finally, Chapter 10 describes the results of pulmonary flow dynamics in relationship with right ventricular function in patients after the Ross procedure. In Chapter 11 all studies presented in this thesis are summarized and future directions are discussed. Show less
