Artifacts-reduced 2D cine SSFP with flow compensation for myocardial BOLD imaging
© Zhou et al; licensee BioMed Central Ltd. 2010
Published: 21 January 2010
Robust image quality is critical for reliable detection and evaluation of myocardial oxygenation changes with blood-oxygen-level-dependent (BOLD) imaging. Recently, balanced SSFP methods have been employed to overcome image quality limitations associated with myocardial BOLD methods. However, the long TRs required for BOLD contrast, can lead to unwanted flow/motion artifacts, ultimately compromising image quality.
To minimize flow/motion artifacts in cardiac phase-resolved SSFP BOLD imaging.
Six dogs were studied in a 1.5 T scanner using first-order flow/motion-compensated SSFP method over the whole left ventricle. Basal, mid-ventricular, and apical images were acquired in cine mode with three different approaches: (A) TR = 3.5 ms (conventional); (B) TR = 6.2 ms (without compensation); and (C) TR = 6.2 ms (with flow/motion compensation). Three experts used (i) Ghost artifacts (GA), an impression of artifacts observed within the image; and (ii) myocardial inhomogeneity (MI), a measure of the signal homogeneity within the left-ventricular myocardium, to evaluate myocardial signal characteristics. One-way ANOVA was performed to ascertain whether there were any differences in the indices with various approaches.
Preliminary myocardial BOLD studies were performed on animals (n = 2) with controllable LCX stenosis to evaluate the benefits of flow compensation. Studies were performed under rest and adenosine stress in the absence or presence of severe (80-90%) stenosis. Other scan parameters were: matrix = 126 × 192; FOV = 157.5 mm × 240 mm; slice-thickness = 5 mm; TE = 3.1 ms; and flip-angle = 70°.
First-order flow/motion compensation strategy employed in this study provides significant improvement in image quality compared to the standard cine BOLD-SSFP MRI. The method proposed here may enable a more reliable means for evaluating BOLD signal changes over the entire cardiac cycle.
This article is published under license to BioMed Central Ltd.