Assesment of cardiac volumes in children with congenital heart disease using a 3D dual cardiac phase technique and a new segmentation tool
Journal of Cardiovascular Magnetic Resonance volume 12, Article number: P2 (2010)
For children with complex congenital heart disease (CHD), the decision regarding univentricular or biventricular surgical repair may depend on accurate ventricular volume assessment. We have previously shown that three-dimensional (3d) whole-heart imaging acquired during end-systole and end-diastole (dual-phase) during one free-breathing MRI examination, when combined with semi-automatic analysis, may be more reproducible in calculating ventricular volumes than standard techniques (Uribe et al, 2008). We describe here, for the first time, use of 3d dual-phase imaging in children with complex CHD.
To show 3d dual-phase imaging is feasible in children with complex CHD despite high heart rates.
The dual-phase sequence was used alongside standard 2d multi-slice cine in ten children with complex CHD (table 1). Analysis required a new semi-automatic segmentation tool which incorporates multiplanar reformatting and volume rendering to identify ventricular boundaries (ViewForum, Philips Healthcare, Figure 1). Two observers independently assessed end-diastolic and end-systolic ventricular volumes using both standard 2d cine with manual segmentation and new 3d dual-phase with semi-automatic segmentation. If applicable, stroke volumes obtained were compared to phase contrast results. Bland-Altman was used to assess agreement and Pearson's coefficient for correlation.
The mean age was 3 yrs (range 3 months-9 yrs) and heart rate range was 58-139 bpm. Volumetric analysis was feasible in all cases. Inter- and Intra-observer variability was similar for both methods. For 2d cine, acquired resolution was 1.8 mm × 1.8 mm; slice thickness 5 to 6 mm & temporal resolution 30 ms (20-40 phases). For 3d dual-phase, acquired resolution was 1.3 mm isotropic & temporal resolution 60 ms (2 phases). Bland-Altman (Figure 2A (systole), 2B (diastole)) showed excellent agreement between standard 2d cine and 3d dual-phase analyses (also, correlation 0.96(systole) and 0.93(diastole)). Similarly, Bland Altman for phase contrast stroke volume showed slightly better agreement with 3d dual-phase (Figure 2C) than with standard 2d cine (Figure 2D) (correlation 0.90 and 0.88 respectively).
Standard ventricular analysis involves manual segmentation of cross-sectional cine images acquired over several breath-holds. This can have problems with slice misalignment. Furthermore, lack of isotropic resolution (by using thick slices which move during the cardiac cycle) makes definition of atrio-ventricular & ventriculo-arterial boundaries difficult. Therefore, acquisition and segmentation relies on operator experience. We believe that 3d dual-phase imaging with semi-automatic analysis overcomes these issues. This study demonstrates that 3d dual-phase imaging can successfully be performed even in very young children with complex CHD. Reliable and valid volumetric analysis was possible using the new semi-automatic segmentation technique.
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Hussain, T., Bellsham-Revell, H., Uribe, S. et al. Assesment of cardiac volumes in children with congenital heart disease using a 3D dual cardiac phase technique and a new segmentation tool. J Cardiovasc Magn Reson 12 (Suppl 1), P2 (2010). https://doi.org/10.1186/1532-429X-12-S1-P2