- Poster presentation
- Open Access
Dynamic MRI of the fetal myocardium
© Roy et al; licensee BioMed Central Ltd. 2012
- Published: 1 February 2012
- Congenital Heart Disease
- Fetal Heart
- Chamber View
- Cardiac Gating
- Atrioventricular Groove
Fetal cardiovascular MRI has been hampered by the lack of a reliable cardiac gating signal. A recently proposed solution to this problem is metric optimized gating (MOG) [1–3]. Here, we demonstrate the ability of MOG to acquire images of the fetal myocardium without conventional cardiac gating. Our work is motivated by the need for high-resolution dynamic imaging in the assessment of fetal congenital heart disease .
Fetal scans were performed using a 1.5T Avanto MRI system (Siemens, Germany). Scan lengths were kept as short as possible to avoid artifact from fetal movement (~ 5-10 seconds/slice). Data were acquired using a conventional cine pulse sequence triggered by a synthetic cardiac gating signal. The period of this trigger was constant, and chosen to be longer than the expected duration of the fetal cardiac cycle. This ensured that each line of k-space was acquired for every cardiac phase. Data were then retrospectively sorted and reconstructed using hypothetical cardiac triggers. The positions of these triggers were iteratively adjusted according to the MOG method until a metric for image quality (entropy) was optimized [1, 2, 5].
Using MOG, MRI of the human fetal myocardium was possible despite the absence of conventional cardiac gating. We were able to identify moving structures of interest during radial (Figure 1) and longitudinal (Figure 2) contraction, thus capturing normal fetal myocardial motion and permitting assessment of cardiac function. Furthermore, visualization of these results as movie loops provided the location of several features of interest that would not be visible without synchronization to the underlying fetal cardiac cycle.
Christopher Roy was supported through a studentship in part by the Ontario Opportunity Trust Fund - Hospital for Sick Children Foundation Student Scholarship Program and a Canadian Graduate Scholarship from the Natural Sciences and Engineering Research Council of Canada.
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