Novel Z Scores to Correct Biases Due to Ventricular Volume Indexation to Body Surface Area in Adolescents and Young Adults.

Abstract Background Reference values for cardiac magnetic resonance imaging (cMRI) in children and young adults are scarce. This leads to risk stratification of patients with congenital heart diseases to be based on volumes indexed to body surface area (BSA). We aimed to produce cMRI Z score equations for ventricular volumes in children and young adults and test whether indexing to BSA resulted in an incorrect assessment of ventricular dilatation according to sex, body composition and growth. Methods We retrospectively included 372 subjects aged Results Ventricular volume Z scores were independent from age, sex and anthropometric measurements, while volumes indexed to BSA showed significant residual association with sex and body size. In TOF subjects, indexation overestimated dilatation in growing children and underestimated dilatation in females compared to males, and in overweight compared to lean subjects. Conclusions Indexed ventricular volumes measured with cMRI did not completely adjust for body size and resulted in a differential error in the assessment of ventricular dilatation according to sex and body size. Our proposed Z score equations solved this problem. Future studies should evaluate if ventricular volumes expressed as Z scores have a better prognostic value compared to volumes indexed to BSA.