title: Dynamic exercise imaging with an MR-compatible stationary cycle within the general electric open magnet.
abstract: 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.
authors.affiliation: Department of Mechanical Engineering, Stanford University, California, USA.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Cheng
authors.forename: Douglas F
authors.initials: DF
authors.lastname: Schwandt
authors.forename: Eric L
authors.initials: EL
authors.lastname: Topp
authors.forename: James H
authors.initials: JH
authors.lastname: Anderson
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Herfkens
authors.forename: Charles A
authors.initials: CA
authors.lastname: Taylor
mesh_terms: 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