- Workshop presentation
- Open Access
Simultaneous wall and blood-flow phase-contrast imaging using a single low VENC
© Liu et al; licensee BioMed Central Ltd. 2012
Published: 1 February 2012
The aim of this study is to investigate the feasibility of extracting motion information from a single scan with one low VENC, followed by robust phase unwrapping, for characterizing both intra-ventricular flow and myocardial motion.
Intra-ventricular blood flow and regional myocardial motion are two key components used in assessing cardiac function. Both can be quantified using phase contrast MRI, but typically require two imaging sequences to be acquired - one with a high velocity encoding value (VENC) and one with a low VENC, selected to optimize velocity sensitivity while avoiding aliasing. In an effort to obtain velocity information from both ventricular blood and myocardial motion in one acquisition, dual-VENC techniques (Buchenberg, ISMRM 2011) have been proposed and evaluated.
MR imaging was performed on a 3.0-T whole-body scanner (MR 750, GE Medical Systems). Phase-contrast images with through-plane velocity-encoding were acquired in the short-axis plane with a retrospectively triggered 2D fast cine phase contrast pulse sequence (segmented k-space gradient-echo; TR/TE, 7.3/4.4 ms; flip angle 15 degree, slice thickness 8 mm) with first-order flow compensation in all dimensions to minimize artifacts from flow and motion. Three VENCs - 75, 20 and 10 cm/s - were used and the images acquired with VENC = 75 cm/s were used as a reference. The acquisition time (per VENC) was about 15 seconds, enabling acquisition within a single breath-hold. Thirty images were reconstructed per cardiac cycle.
All images were analyzed off-line using algorithms developed using MATLAB. Phase unwrapping of the velocity data was achieved using an algorithm developed in our lab, which uses an orthogonal recursive approach to remove streaks that result following conventional 2D phase unwrapping.
The results suggest that single low-VENC (>= 20 cm/s) acquisitions can be successfully used to measure intra-ventricular flow and wall motion simultaneously.
This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.