Age- and Sex-specific Reference Ranges for Cardiac Function and Structure in Germany: Cardiovascular Magnetic Resonance Imaging (CMR) in the German National Cohort (NAKO)

AO_SCPLOWBSTRACTC_SCPLOWO_ST_ABSIntroductionC_ST_ABSCardiovascular magnetic resonance (CMR) is the reference standard for quantifying cardiac structure and function, yet widely applicable population-based reference values remain limited. We derived age- and sex-specific reference ranges for ventricular volumes, mass, and function using data from the population-based German National Cohort (NAKO). MethodsShort-axis balanced steady-state free precession cine images from 3T CMR of 29,908 participants were analyzed using a validated deep learning segmentation pipeline with systematic quality control. From these, we defined a main reference cohort free of cardiovascular disease (CVD), and a healthy subcohort additionally free of cardiovascular risk factors. Standard left (LV) and right ventricular (RV) measures were quantified and indexed. Reference intervals (5th-95th percentiles) were modeled using additive models and quantile regression to capture non-linear age trends, stratified by sex, with formal testing for age-sex interactions. ResultsThe CVD-free reference cohort included 24,371 participants (mean age 43.8{+/-}12.2 years; age range 20-72 years, 44.7% women). LV and RV end-diastolic and end-systolic volumes declined with age, whereas LV ejection fraction remained stable and RV ejection fraction increased modestly. Sex differences were consistent across metrics and all major parameters demonstrated significant age-sex interactions; differences were most pronounced at younger ages and attenuated in later life. The healthy subcohort (n=5,550) showed similar structural and functional profiles, without clinically relevant deviations from the main reference cohort. ConclusionsThis study provides age- and sex-specific CMR reference ranges derived from a large, uniformly imaged national cohort. These data offer a population-based normative framework for clinical CMR interpretation and future research on sex-specific cardiac remodeling and healthy aging.