Exploiting sparsity to accelerate noncontrast MR angiography in the context of parallel imaging
Article first published online: 29 AUG 2011
Copyright © 2011 Wiley Periodicals, Inc.
Magnetic Resonance in Medicine
Volume 67, Issue 5, pages 1391–1400, May 2012
How to Cite
Storey, P., Otazo, R., Lim, R. P., Kim, S., Fleysher, L., Oesingmann, N., Lee, V. S. and Sodickson, D. K. (2012), Exploiting sparsity to accelerate noncontrast MR angiography in the context of parallel imaging. Magn Reson Med, 67: 1391–1400. doi: 10.1002/mrm.23132
- Issue published online: 6 APR 2012
- Article first published online: 29 AUG 2011
- Manuscript Accepted: 11 JUL 2011
- Manuscript Revised: 16 JUN 2011
- Manuscript Received: 31 JAN 2011
- NIH. Grant Numbers: R01 HL092439, R01 EB000447
- noncontrast MR angiography;
- parallel imaging;
Noncontrast techniques for peripheral MR angiography are receiving renewed interest because of safety concerns about the use of gadolinium in patients with renal insufficiency. One class of techniques involves subtraction of dark-blood images acquired during fast systolic flow from bright-blood images obtained during slow diastolic flow. The goal of this work was to determine whether the inherent sparsity of the difference images could be exploited to achieve greater acceleration without loss of image quality in the context of generalized autocalibrating partially parallel acquisition (GRAPPA). It is shown that noise amplification at high acceleration factors can be reduced by performing subtraction on the raw data, before calculation of the GRAPPA weights, rather than on the final magnitude images. Use of the difference data to calculate the GRAPPA weights decreases the geometry factor (g-factor), because the difference data represent a sparse image set. This demonstrates an inherent property of GRAPPA and does not require the use of compressed sensing. Application of this approach to highly accelerated data from healthy volunteers resulted in similar depiction of large arteries to that obtained with low acceleration and standard reconstruction. However, visualization of very small vessels and arterial branches was compromised. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.