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

Area of Science:

• Cardiovascular Physiology
• Exercise Science
• Medical Imaging

Background:

• Conventional cardiopulmonary exercise testing (CPET) assesses exercise capacity.
• Understanding the physiological determinants of peak oxygen consumption (VO2) is crucial, especially in cardiac disease.
• Integrating magnetic resonance imaging (MRI) with CPET offers potential for enhanced physiological assessment.

Purpose of the Study:

• To evaluate the feasibility and acceptability of MRI-augmented cardiopulmonary exercise testing (MR-CPET) in healthy adults.
• To determine the correlation between peak exercise values obtained from conventional CPET and MR-CPET.
• To investigate the relationship between peak oxygen consumption (VO2) and both peak cardiac output (CO) and peak oxygen extraction (ΔcO2) during MR-CPET.

Main Methods:

• Seventeen healthy adults underwent both conventional CPET and MR-CPET using MR-compatible equipment.
• Continuous aortic flow was measured using a validated UNFOLD-SENSE spiral phase contrast magnetic resonance (PCMR) sequence.
• Peak VO2, VCO2, VE, CO, and ΔcO2 were analyzed and compared between the two testing modalities.

Main Results:

• Fifteen of 17 participants completed MR-CPET, indicating good feasibility, with acceptable, though slightly lower, participant satisfaction compared to conventional CPET.
• Strong correlations were observed between conventional and MR-CPET for peak VO2 (r=0.94), VCO2 (r=0.87), and VE (r=0.88).
• Peak CO and ΔcO2 were identified as independent predictors of peak VO2 in both MR-CPET and conventional CPET.

Conclusions:

• MR-CPET is a feasible and acceptable method for assessing exercise physiology in healthy adults.
• MR-CPET provides strong correlations with conventional CPET for key exercise parameters.
• This technique allows for the differentiation of cardiac output and oxygen extraction contributions to peak VO2 variations, offering insights into reduced exercise capacity in conditions like cardiac disease.