1 research outputs found
Magnetic Resonance Imaging of the Neonatal Cardiovascular System : Impact of Patent Ductus Arteriosus
The incidence of premature birth is increasing in absolute number and as a proportion of all births
around the world. Many pathologies seen in this cohort are related to abnormal blood supply. Fetal
and premature cardiovascular systems differ greatly as to maintain adequate blood flow to the
developing organs in the uterine and extra-uterine environments require very different circulations.
Subsequently following preterm birth the immature cardiovascular system undergoes abrupt
adaptations, often resulting in the prolonged patency of the fetal shunt, ductus arteriosus. The
impact of a patent ductus arteriosus (PDA) is poorly understood. However it is thought that large
ductal shunt volumes may result in congestive cardiac failure and systemic hypo-‐perfusion.
Cardiac MRI has contributed greatly to the understanding of many cardiovascular diseases and
congenital defects in paediatric and adult patients. Translating these imaging techniques to assess
the preterm cardiovascular system requires careful optimization due to their condition, size and
significantly increased heart rate. The work presented in this thesis employs multiple functional CMR
techniques to investigate the preterm cardiovascular system in the presence and absence of PDA
and the resultant cardiac function.
A novel technique utilizing PC MRI to quantify PDA shunt volume and its impact on flow distribution
is presented. Despite large shunt volumes, systemic circulation remained within normal range,
although slight reduction is detectable when assessed at group level. Subsequently the impact of
PDA and associated increased work load on left ventricular dimensions and function was then
investigated using SSFP imaging. Results indicated that cardiac function was maintained even in the
presence of large shunt volumes. Finally 4D PC sequences were employed to evaluate pulse wave
velocity and flow regime within the preterm aorta, demonstrating the feasibility of hemodynamic
assessment in this cohort. The findings of these studies provide insight into the impact of PDA. The
reliable measurement and assessment of preterm cardiovascular system provides the potential to
improve the understanding of the development and effects of certain pathologies seen in this
cohort.Open Acces