High-field phase-contrast magnetic resonance imaging (PC-MRI) enables quantification of ventricular output, although measurements may be affected by anesthesia-related variables. The present study investigated the influence of recumbency and airway pressure on cardiac index derived from 3.0T two-dimensional PC-MRI in dogs. Six clinically asymptomatic client-owned dogs underwent PC-MRI at the aortic valve (AV) and pulmonic valve (PV). Imaging was performed under zero end-expiratory pressure (ZEEP) in three positions: supine (dorsal recumbency; DR), right lateral recumbency (RLR), and left lateral recumbency (LLR). The DR acquisition was repeated during a CPAP 10 condition, defined as sustained airway pressure of 10cmH₂O during brief apnea for PC-MRI acquisition. Left ventricular cardiac index (LV CI), right ventricular cardiac index (RV CI), and the RV/LV CI ratio were compared across these conditions. Differences were assessed using repeated-measures and paired analyses, and complementary estimation metrics were reported; nominal P<0.05 was considered significant. Under ZEEP, RV CI in both lateral recumbencies was approximately 14–15% higher than in DR, whereas LV CI showed smaller directional increases. In DR, LV CI and RV CI showed non-significant directional decreases of approximately 7–10% under CPAP 10 compared with ZEEP. These preliminary findings suggest that recumbency and airway-pressure conditions may contribute to measurable within-dog variation in PC-MRI–derived ventricular cardiac indices in anesthetized dogs, supporting the need for standardized acquisition conditions in future studies.

To Cite This Article: Lee C, Lee K and Yoon H, 2026. Position and airway pressure dependent right and left ventricular flow with 3.0t cardiac mri in dogs. Pak Vet J, 46(6): 1516-1524. http://dx.doi.org/10.29261/pakvetj/2026.143