Measurement of aortic and pulmonary flow with MRI at rest and during physical exercise

Purpose: Our aim was to assess the feasibility of measuring great vessel flow during submaximal exercise using MR now mapping. Method: In 16 healthy volunteers, MR measurements of great vessel flow were obtained at rest and during two levels of submaximal physical exercise using an MR-compatible bicycle ergometer. Results: Great vessel flow showed good correlation at rest and during exercise (r = 0.9, p < 0.0005). Significant increase in heart rate was observed during exercise. Aortic flow volume increased from 64 +/- 13 ml/beat at rest to 71 +/- 11 ml/beat at 50 W (p < 0.0005) to 79 +/- 13 ml/beat at 100 W (p < 0.0005). Pulmonary flow volume increased from 63 +/- 14 ml/beat at rest to 70 +/- 13 ml/beat at 50 W (p < 0.005) to 76 +/- 12 ml/beat at 100 W (p = NS). Conclusion: Quantification of great vessel flow can be performed safely in healthy volunteers using MR flow measurements during submaximal physical exercise. These measurements may be used to study hemodynamic abnormalities in patients with cardiac disease.