European researchers have shown that heart imagers can have their MRI and their patients on exercise bikes—pedaling harder and harder—too.

Johan Heiberg, PhD, and colleagues at Aarhus University Hospital in Denmark acquired real-time, high-quality MR images of the aorta at increasingly intense exercise levels from 40 patients using an MRI-compatible ergometer bike mounted on the scanner table, their feet strapped to the pedals.

Half the patients had previously been operated on for ventricular septal defect; the other 20 were healthy volunteers.

All completed the exercise protocol, topping out at a mean maximum cardiac output of 13.7 ± 3.7 liters per minute and a heart rate of 150 ± 16 beats per minute, the authors report.

Fewer than 1 percent of the scans had to be discarded due to poor image quality.

Publishing their findings online in Clinical Imaging, the authors conclude that gradually increasing patients’ exercise intensity from rest to heavy exertion is feasible using phase-contrast real-time MRI combined with an MRI-specific bicycling device.

(For images of the exercise equipment they used, click here.)

Heiberg and colleagues write that their study “strengthens stress MRI as a technique for radiologists or cardiologists to discover cardiovascular disease that is not apparent at rest, and with the ability to assess cardiac output at numerous stages from rest to high exercise levels.”

They suggest their bike-based methodology has the potential to become a widely accepted, albeit alternative, means of assessing cardiac output.