MR augmented cardiopulmonary exercise testing-a novel approach to assessing cardiovascular function

Barber, Nathaniel J; Ako, Emmanuel
O; Kowalik, Grzegorz T; Steeden, Jennifer A; Pandya, Bejal; Muthurangu,

Physiological Measurement, May 2015, Vol. 36 Issue: Number 5
pN85-N94, 10p

Abstract: The purposes of this study were: (1) to
evaluate feasibility and acceptability of MRI augmented cardiopulmonary
exercise testing (MR-CPET) in healthy adults and (2) to test whether
peak values obtained at conventional and MR-CPET correlate and to
demonstrate variation in peak oxygen consumption (VO2) relates to both
peak cardiac output (CO) and peak oxygen extraction (DcO2).

Seventeen  healthy adults underwent CPET and MR-CPET using an MR compatible
ergometer and CPET system customised for MR use. Continuous aortic flow
measurement used a validated UNFOLD-SENSE spiral phase contrast
magnetic resonance (PCMR) sequence.Fifteen of 17 volunteers completed
exercise; exclusions were due to claustrophobia and inability to
effectively master exercise technique. Measures of acceptability were
lower but still satisfactory for MR-CPET.There were strong correlations
between conventional and MR-CPET for peak VO2 (r = 0.94, p < 0.001);
VCO2 (r = 0.87, p < 0.001) and VE (r = 0.88, p < 0.001).Multiple linear
regression analysis demonstrated peak CO and DcO2 were independent
predictors of peak VO2 measured during MR-CPET (b = 0.73 and 0.38 p <
0.0001) and conventional CPET (b = 0.78, 0.28 p < 0.0001).MR-CPET is
feasible, acceptable and demonstrates physiology not apparent with
conventional CPET.
MR-CPET allows differentiation of the contributions
of CO and DcO2 to variation in peak VO2. We believe that this will be
useful in understanding the origin of reduced exercise capacity in
cardiac disease.