Our study demonstrated good repeatability and reproducibility for ultrasonic measurements of left cardiac structures in children, showing that values obtained for measurement of these structures in both clinical and epidemiological research projects can be confidently accepted.

The aim of the investigation reported here was to assess the intraobserver and interobserver variability of renal measurements in children. The study comprised 56 paired measurements in 28 children (median age 7.5 years, range 3.0-15.0 years) without renal or ureterovesical anomalies. Intraobserver and interobserver reproducibility was assessed by repeated measurements of the left and right renal length, width, and thickness. Intraclass correlation coefficients (ICCs) with the corresponding 95% confidence interval (CI) were calculated. Bland and Altman plots were computed to assess the agreement of the measurements. Limits of agreement +/- 2 standard deviations (SD) for the mean differences in renal measurements were derived. Intraobserver ICCs ranged from 0.93 (left and right renal width and right renal thickness) to 0.99 (left renal length), and interobserver ICCs ranged from 0.64 (right renal thickness) to 0.90 (right renal length). Limits of agreement in the Bland and Altman plots ranged from -8.0 to 9.2% (intraobserver left renal width) to the widest limit from -18.0 to 19.2% (interobserver left renal length). Overall, this study demonstrated the good reproducibility and agreement of most renal dimensions in children measured by ultrasound (US). Based on these results, we conclude that US is an appropriate measure to assess renal dimensions in both clinical and epidemiological studies.

Subcoronary implantation has a learning curve, resulting in more initial aortic regurgitation and early reoperation compared with root replacement. In both techniques, progression of aortic regurgitation over time is small but accelerated in young adults.