Dynamic exercise imaging with an MR-compatible stationary cycle within the general electric open magnet.
Many cases of muscular ischemia do not manifest without increased metabolic demand. Hence, diagnosis of intermittent claudication often requires inducing physiologic challenge, such as by exercise. Cine phase-contrast MRI can concurrently acquire cross-sectional vascular anatomy and through-plane blood velocities, enabling blood flow rate quantification. An MR-compatible stationary cycle was designed, constructed, and tested for flow quantification in large arteries during lower-limb exercise in a General Electric Signa SP 0.5 T open magnet. The cycle demonstrated smooth cycling during image acquisition, has freewheeling capability, is adjustable for subject size and strength, and can quantify workload. A healthy 59-year-old male was imaged at the supraceliac and infrarenal levels of the abdominal aorta at rest and during exercise. An exercise workload of 47.9 W was achieved. His heart rate increased from 52 to 78 bpm, supraceliac flow increased from 1.7 to 3.7 L/min, and infrarenal flow increased from 0.4 to 3.2 L/min from rest to exercise.
Cheng
Christopher P
CP
Department of Mechanical Engineering, Stanford University, California, USA.
Schwandt
Douglas F
DF
Topp
Eric L
EL
Anderson
James H
JH
Herfkens
Robert J
RJ
Taylor
Charles A
CA
D001012:Aorta, Abdominal / Q000502:physiology*; D001783:Blood Flow Velocity; D004867:Equipment Design; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D012016:Reference Values