Exercise cardiac magnetic resonance imaging across the lifespan

Exercise cardiac magnetic resonance imaging (cMRI) offers several advantages over contemporary stress imaging approaches, including improved spatial resolution, free of ionizing radiation. With exercise cMRI becoming increasingly popular, more work is needed to better understand the hemodynamic response across the lifespan.

To compare the cMRI response to exercise across the lifespan.

To accomplish this purpose, we leveraged data from several ongoing imaging studies in which healthy control participants completed exercise cMRI across at least two discrete workloads, ranging in intensity from mild to moderate. Imaging was performed using either a 1.5T or 3T Phillips MRI scanner. Exercise was performed using an MR compatible ergometer (Cardio Step, Ergospect GmbH, Innsbruck, Austria). Volumetric data were measured from a stack of short axis images spanning the length of the left ventricle from base to apex.

Exercise cardiac magnetic resonance images were available from 48 participants, ranging in age from 10 to 81 years. On average, end-diastolic volume remained unchanged with exercise (73±14 vs. 75±15 vs. 74±14 mL, rest vs. mild vs moderate, p = 0.107), while end-systolic volume was reduced (27±7 vs. 25±7 vs. 23±6 mL, p = <.001), resulting in a modest increase in stroke volume (46±9 vs. 50±10 vs. 51±10 mL, p = <.001). To evaluate the influence of age, we compared the youngest participants (n = 13, 10-30 yrs) against the oldest participants (n = 18, 65-81yrs). As illustrated in Figure 1, while baseline volumes differed significantly with age, the relative response to exercise was similar between groups. Likewise, to evaluate the influence of sex, we compared male (n = 21) versus female (n = 27) participants. As illustrated in panels D-F, ventricular volumes were greater in men compared with women, but the exercise relative responses were similar.

Taken together, these data add to a growing body of literature highlighting the feasibility of exercise cardiac magnetic resonance imaging across the lifespan, and begin to define the normative response for future clinical comparison.