Pediatric aortic root z-scores (aortic valve, sinus of Valsalva, and ascending aorta) adjusted for height and weight. This multivariable model was developed specifically to minimize z-score bias related to BMI. Particular attention was paid to the statistical design such that resulting z-scores are valid, without residual association to body size and conforming to a normal distribution with a mean of 0 and an SD of 1.

"This should be viewed as a proof of concept that bivariate models may be insufficient as a normalization tool in pediatric echocardiography."