- Meeting abstract
- Open Access
110 Myofiber developmental plasticity in fetal hearts delineated with diffusion tensor MRI
© Zhang et al; licensee BioMed Central Ltd. 2008
- Published: 22 October 2008
- Apparent Diffusion Coefficient
- Diffusion Tensor Image
- Fetal Heart
- Gestation Period
- Adult Heart
Myocardial fiber structure is a critical determinant of cardiac function. Previous studies have shown that the right ventricle workload is greater in the gestational period than that after birth. We hypothesized that myofiber structure in developing heart would differ from that of the adult heart. The objective of this study was to quantify myocardial fiber structure in fetal pig hearts at 60 day gestation period, which is equivalent to 150 days in human, with the use of diffusion tensor MRI (DTI) and to compare that with our previous result in adult hearts.
Fetal pigs (n = 6) at 60 day gestation period preserved in formalin were purchased from Nebraska Scientific, Omaha, NE. Hearts were excised and fixed in 10% formalin solution. Before MR scanning, each heart was rinsed by phosphate buffered saline (PBS) and kept in PBS for 24 hours. DTI of fetal pig heart was performed on an 11.74 T Varian INOVA MR system using a 3 cm birdcage coil. Diffusion tensor images were acquired using a multi-slice diffusion-weighted spin-echo pulse sequence with the following parameters: TR, 2 s; TE, 33 ms; δ, 5 ms, Δ, 20 ms; b-value, 0 and 1063 s/mm2; direction of applied diffusion-weighting gradients, 7; slice thickness, 0.5 mm; and in-plane resolution, 156 × 156 μm. Myofiber orientation in each voxel was estimated as the direction exhibiting maximal apparent diffusion coefficient of water. Reconstructed myofiber orientations were projected onto the short-axis plane of the heart to illustrate the orientations of myocardial fibers. These measured fiber orientations were compared with our previous analogous results in adult rat hearts to characterize the difference in myofiber structures between fetal and adult hearts (n = 11).
Myocardial fiber structure in fetal hearts differed from that in adult hearts and reflected a balanced contribution to both the left ventricle and the right ventricle. After maturation, these fibers tracked almost exclusively to the left ventricle and lost their contribution to right ventricular architecture. These marked structural rearrangements reflect the plasticity of myocardial fiber development in response to programmed alterations in contractile function that occur after birth.
This article is published under license to BioMed Central Ltd.