title: Rapid cardiac-output measurement with ungated spiral phase contrast.
abstract: An ungated spiral phase-contrast (USPC) method was used to measure cardiac output (CO) rapidly and conveniently. The USPC method, which was originally designed for small peripheral vessels, was modified to assess CO by measuring flow in the ascending aorta (AA). The modified USPC used a 12-interleaf spiral trajectory to acquire full-image data every 283 ms with 2-mm spatial resolution. The total scan time was 5 s. For comparison, a triggered real-time (TRT) method was used to indirectly calculate CO by measuring left-ventricular (LV) volume. The USPC and TRT measurements from all normal volunteers agreed. In a patient with patent ductus arteriosus (PDA), high CO was measured with USPC, which agreed well with the invasive cardiac-catheterized measurement. In normal volunteers, CO dropped about 20-30% with Valsalva maneuvering, and increased about 100% after exercise. Continuous 28-s cycling between Valsalva maneuvering and free-breathing showed that USPC can temporally resolve physiological CO changes.
authors.affiliation: Magnetic Resonance Systems Research Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California, USA. piquant@mrsrl.stanford.edu
authors.forename: Jong B
authors.initials: JB
authors.lastname: Park
authors.forename: Bob S
authors.initials: BS
authors.lastname: Hu
authors.forename: Steven M
authors.initials: SM
authors.lastname: Conolly
authors.forename: Krishna S
authors.initials: KS
authors.lastname: Nayak
authors.forename: Dwight G
authors.initials: DG
authors.lastname: Nishimura
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D002302:Cardiac Output / Q000502:physiology*; D004374:Ductus Arteriosus, Patent / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D014636:Valsalva Maneuver