To validate a novel semi-automatic segmentation algorithm for MR-derived volume and function measurements by comparing it with the standard method of manual contour tracing. The new algorithms excludes papillary muscles and trabeculae from the blood pool, while the manual approach includes these objects in the blood pool. An epicardial contour served as input for both methods. Multiphase 2D steady-state free precession short axis images were acquired in 12 subjects with normal heart function and in a dynamic anthropomorphic heart phantom on a 1.5 T MR system. In the heart phantom, manually and semi-automatically measured cardiac parameters were compared to the true end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF). In the subjects, the semi-automatic method was compared to manual contouring in terms of difference in measured EDV, ESV, EF and myocardial volume (MV). For all measures, intra- and inter-observer agreement was determined. In the heart phantom, EDV and ESV were underestimated for both the semi-automatic. As the papillary muscles were excluded from the blood pool with the semi-automatic method, EDV and ESV were approximately 20 ml lower in the patients, whereas EF was approximately 16 % higher. Intra- and inter-observer agreement was overall improved with the semi-automatic method compared to the manual method. Correlation between manual and semi-automatic measurements was high (EDV: R = 0.99, ESV: R = 0.96; EF: R = 0.80, MV: R = 0.99). The semi-automatic method could exclude endoluminal muscular structures from the blood volume with significantly improved intra- and inter-observer variabilities in cardiac function measurements compared to the conventional, manual method, which includes endoluminal structures in the blood volume.

The objective of this study was to assess the impact of right ventricular (RV) trabeculae and papillary muscles on measured volumes and function assessed by cardiovascular magnetic resonance imaging in patients with repaired tetralogy of Fallot. Sixty-five patients with repaired tetralogy of Fallot underwent routine cardiovascular magnetic resonance imaging. Endocardial and epicardial contours were drawn manually and included trabeculae and papillary muscles in the blood volume. Semi-automatic threshold-based segmentation software excluded these structures. Both methods were compared in terms of end-diastolic, end-systolic and stroke volume, ejection fraction and mass. Observer agreement was determined for all measures. Exclusion of trabeculae and papillary muscle in the RV blood volume decreased measured RV end-diastolic volume by 15 % (from 140 ± 35 to 120 ± 32 ml/m(2)) compared to inclusion, end-systolic volume by 21 % (from 74 ± 23 to 59 ± 20 ml/m(2)), stroke volume by 9 % (from 66 ± 16 to 60 ± 16 ml/m(2)) and relatively increased ejection fraction by 7 % (from 48 ± 7 to 51 ± 8 %) and end-diastolic mass by 79 % (from 28 ± 7 to 51 ± 10 g/m(2)), p < .01. Excluding trabeculae and papillary muscle resulted in an improved interobserver agreement of RV mass compared to including these structures (coefficient of agreement of 87 versus 78 %, p < .01). Trabeculae and papillary muscle significantly affect measured RV volumes, function and mass. Semi-automatic threshold-based segmentation software can reliably exclude trabeculae and papillary muscles from the RV blood volume.

Compared with previous literature on acquired valvar disease, we found a higher incidence of valve-related complications in patients with congenital heart disease that was unrelated to prosthesis material. Our data suggest that PPM may have a negative effect on the event-free interval.