Karlsson P; Department of Medical Sciences: Clinical Physiology, Uppsala University, Uppsala, Sweden.
Strand R; Kullberg J; DMichaëlsson K; DeAhlström H; Division of Radiology, Lind L; Malinovschi A;
Scientific reports [Sci Rep] 2024 Sep 16; Vol. 14 (1), pp. 21633.
Date of Electronic Publication: 2024 Sep 16.
A cardiopulmonary exercise test (CPET) is a test assessing an individual’s physiological response during exercise. Results may be affected by body composition, which is best evaluated through imaging techniques like magnetic resonance imaging (MRI). The aim of this study was to assess relationships between body composition and indices obtained from CPET. A total of 234 participants (112 female), all aged 50 years, underwent CPETs and whole-body MRI scans (> 1 million voxels). Voxel-wise statistical analysis of tissue volume and fat content was carried out with a method called Imiomics and related to the CPET indices peak oxygen consumption (V̇O 2peak ), V̇O 2peak scaled by body weight (V̇O 2kg ) and by total lean mass (V̇O 2lean ), ventilatory efficiency (V̇E/V̇CO 2 -slope), work efficiency (ΔV̇O 2 /ΔWR) and peak exercise respiratory exchange ratio (RERpeak). V̇O 2peak showed the highest positive correlation with volume of skeletal muscle. V̇O 2kg negatively correlated with tissue volume in subcutaneous fat, particularly gluteal fat. RERpeak negatively correlated with tissue volume in skeletal muscle, subcutaneous fat, visceral fat and liver. Some associations differed between sexes: in females ΔV̇O 2 /ΔWR correlated positively with tissue volume of subcutaneous fat and V̇E/V̇CO 2 -slope with tissue volume of visceral fat, and, in males, V̇O 2peak correlated positively to lung volume. In conclusion, voxel-based Imiomics provided detailed insights into how CPET indices were related to the tissue volume and fat content of different body structures.