Improved estimation of velocity and flow rate using regularized three-point phase-contrast velocimetry

• Published in: Magnetic resonance in medicine 2000-07, Vol.44 (1), p.122-128
• Main Authors: Herment, A., Mousseaux, E., Jolivet, O., DeCesare, A., Frouin, F., Todd-Pokropek, A., Bittoun, J.
• Format: Article
• Language: English
• Subjects: Adult; Algorithms; Aorta - physiology; aortic flow; Biological and medical sciences; Blood Flow Velocity - physiology; Cardiovascular system; Fourier Analysis; Hemorheology; Humans; Image Processing, Computer-Assisted; Investigative techniques, diagnostic techniques (general aspects); Least-Squares Analysis; Linear Models; magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Medical sciences; Middle Aged; Phantoms, Imaging; phase-contrast; Radiodiagnosis. Nmr imagery. Nmr spectrometry; regularization; velocimetry
• ISSN: 0740-3194; 1522-2594
• DOI: 10.1002/1522-2594(200007)44:1<122::AID-MRM18>3.0.CO;2-C

We improved the three‐point phase‐contrast method by regularization of MR velocity data after acquisition of a low velocity‐to‐noise ratio (VNR) velocity image and a high VNR aliased velocity image. The phase unwrapping algorithm is based on the assumed correlation of the velocity of adjacent flow voxels on the low VNR and the unaliased high VNR images. We used Fourier encoding with eight velocity‐encoding gradient steps to obtain reference velocity images of the aorta from five subjects (274 images) and compared them with the phase‐contrast and three‐point phase‐contrast images with and without regularization. The VNR of the regularized velocity image was improved by 9.1 dB and the VNR of the three‐point phase‐contrast velocity image was improved by 0.7 dB with respect to the low first moment velocity image. Corresponding improvements of 9 dB and 3.7 dB were obtained for the estimations of instantaneous flow rate. Magn Reson Med 44:122–128, 2000. © 2000 Wiley‐Liss, Inc.