Rapid quantitation of cardiovascular flow using slice-selective fourier velocity encoding with spiral readouts.
Accurate flow visualization and quantitation is important for the assessment of many cardiovascular conditions such as valvular stenosis and regurgitation. Phase contrast based methods experience partial volume artifacts when flow is highly localized, complex and/or turbulent. Fourier velocity encoding (FVE) avoids such problems by resolving the full velocity distribution within each voxel. This work proposes the use of slice selective FVE with spiral readouts to acquire fully localized velocity distributions in a short breath-hold. Scan-plane prescription is performed using classic protocols, and an automatic algorithm is used for in-plane localization of the flow. Time and spatially-resolved aortic valve velocity distributions with 26-msec temporal resolution and 25 cm/sec velocity resolution over a 600 cm/sec field-of-view were acquired in a 12-heartbeat breath-hold. In carotid studies, scan time was extended to achieve higher spatial resolution. The method was demonstrated in healthy volunteers and patients, and the results compared qualitatively well with Doppler ultrasound. Acquisition time could be reduced to 7 heartbeats (a 42% reduction) using partial Fourier reconstruction along the velocity dimension.
Carvalho
Joao L A
JL
Magnetic Resonance Engineering Laboratory, Department of Electrical Engineering-Systems, University of Southern California, Los Angeles, California, USA. jcarvalh@usc.edu
Nayak
Krishna S
KS
D000465:Algorithms; D001024:Aortic Valve Stenosis / Q000503:physiopathology*; D016477:Artifacts; D001783:Blood Flow Velocity / Q000502:physiology*; D017536:Carotid Artery, Common / Q000502:physiology*; D015150:Echocardiography, Doppler; D005583:Fourier Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*