Detection of Biventricular Volume Increase in Overweight and Obese Individuals Using a Novel Index of the "Standard Human"-A Single-Center, Non-Contrast-Enhanced Cardiac CT Study.

Background/Objectives: Biventricular volume (BVV) can be measured from non-contrast-enhanced CT images in patients undergoing coronary artery calcium (CAC) scoring. BVV correlates with left ventricular mass and may predict mortality risk in type 2 diabetes mellitus patients. This study examines the relationships among body size, age, and BVV using the Standard Human Index (SHI), which combines height and bodyprint (BP = k × height - body surface area, h-BSA; k = 1 for females, 1.1 for males). We hypothesize that this novel indexing method enhances the discrimination of increased BVV in overweight and obese patients and assesses the relevance of age in interpreting BVV changes. Methods: We analyzed CT data from 2466 patients (1606 women, 860 men; mean age 64 ± 11 years) referred for CAC scoring. Fatless BVV was measured semi-automatically, and we compared raw BVV values and BVV normalized for height, body surface area (BSA), and the SHI across sex, age, and body mass index (BMI) categories. Results: BVV was significantly higher in males (414 ± 97 mL) than females (297 ± 66 mL) (p < 0.001). BVV decreased non-linearly with age, stabilizing in older patients. Normal-weight males had higher BVV than females (p < 0.001). Normalization for height, BSA, and the SHI indicated that BSA did not effectively distinguish BVV changes in overweight and obese patients. Conclusions: The proposed index effectively diagnosed BVV increases in overweight individuals, while BSA indexing may be misleading. The age dependence of BVV challenges the validity of standards based on younger populations for detecting ventricular enlargement in older adults.