RV mass measurement at end-systole: Improved accuracy, Reproducibility, and reduced segmentation time

Multicentre reference values for cardiac magnetic resonance imaging derived ventricular size and function for children aged 0-18 years

Aims

Cardiovascular magnetic resonance (CMR) imaging is an important tool in the assessment of paediatric cardiac disease. Reported reference values of ventricular volumes and masses in the paediatric population are based on small cohorts and several methodologic differences between studies exist. We sought to create steady-state free precession (SSFP) CMR reference values for biventricular volumes and mass by combining data of previously published studies and re-analysing these data in a standardized manner.

Methods and results

A total of 141 healthy children (68 boys) from three European centres underwent cine-SSFP CMR imaging. Cardiac structures were manually contoured for end-diastolic and end-systolic phases in the short-axis orientation according to current standardized CMR post-processing guidelines. Volumes and masses were derived from these contours. Age-related reference curves were constructed using the lambda mu sigma method. Median age was 12.7 years (range 0.6–18.5). We report biventricular volumes and masses, unindexed and indexed for body surface area, stratified by age groups. In general, boys had approximately 15% higher biventricular volumes and masses compared with girls. Only in children aged <6 years old no gender differences could be observed. Left ventricle ejection fraction was slightly higher in boys in this study population (median 67% vs. 65%, P = 0.016). Age-related reference curves showed non-linear relations between age and cardiac parameters.

Conclusion

We report volumetric SSFP CMR imaging reference values for children aged 0–18 years old in a relatively large multi-centre cohort. These references can be used in the follow-up of paediatric cardiac disease and for research purposes.

Improved Workflow for Quantification of Right Ventricular Volumes Using Free-Breathing Motion Corrected Cine Imaging

Cardiac MR traditionally requires breath-holding for cine imaging. Younger or less stable patients benefit from free-breathing during cardiac MR but current free-breathing cine images can be spatially blurred. Motion corrected re-binning (MOC) is a novel approach that acquires and then reformats real-time images over multiple cardiac cycles with high spatial resolution. The technique was previously limited by reconstruction time but distributed computing has reduced these times. Using this technique, left ventricular volumetry has compared favorably to breath-held balanced steady-state free precession cine imaging (BH), the current gold-standard, however, right ventricular volumetry validation remains incomplete, limiting the applicability of MOC in clinical practice. Fifty subjects underwent cardiac MR for evaluation of right ventricular size and function by end-diastolic (EDV) and end-systolic (ESV) volumetry. Measurements using MOC were compared to those using BH. Pearson correlation coefficients and Bland-Altman plots tested agreement across techniques. Total scan plus reconstruction times were tested for significant differences using paired t-test. Volumes obtained by MOC compared favorably to BH (R = 0.9911 for EDV, 0.9690 for ESV). Combined acquisition and reconstruction time (previously reported) were reduced 37% for MOC, requiring a mean of 5.2 min compared to 8.2 min for BH (p < 0.0001). Right ventricular volumetry compares favorably to BH using MOC image reconstruction, but is obtained in a fraction of the time. Combined with previous validation of its use for the left ventricle, this novel method now offers an alternative imaging approach in appropriate clinical settings.