Highly accelerated vessel-selective arterial spin labelling angiography using sparsity and smoothness constraints

Journal article

Purpose:

To demonstrate that vessel-selectivity in dynamic arterial spin labeling angiography can be achieved without any scan time penalty or noticeable loss of image quality compared to conventional arterial spin labeling angiography.

Methods:

Simulations on a numerical phantom were used to assess whether the increased sparsity of vessel-encoded angiograms compared to non-vessel-encoded angiograms alone can improve reconstruction results in a compressed sensing framework. Further simulations were performed to study whether the difference in relative sparsity between non-selective and vessel-selective dynamic angiograms were sufficient to achieve similar image quality at matched scan times in the presence of noise. Finally, data were acquired from 5 healthy volunteers to validate the technique in vivo. All data, both simulated and in vivo, were sampled in 2D using a golden angle radial trajectory and reconstructed by enforcing image domain sparsity and temporal smoothness on the angiograms in a parallel imaging and compressed sensing framework.

Results:

Relative sparsity was established as a primary factor governing the reconstruction fidelity. Using the proposed reconstruction scheme, differences between vessel-selective and non-selective angiography were negligible compared to the dominant factor of total scan time in both simulations and in vivo experiments at acceleration factors up to R = 34. The reconstruction quality was not heavily dependent on hand-tuning the parameters of the reconstruction.

Conclusion:

The increase in relative sparsity of vessel-selective angiograms compared to nonselective angiograms can be leveraged to achieve higher acceleration without loss of image quality, resulting in the acquisition of vessel-selective information at no scan time cost.

Authors: Schauman, SS; Chiew, M; Okell, TW

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: Magnetic Resonance in Medicine
• Volume: 83
• Issue: 3
• Pages: 892-905
• Publication date: 2019-09-19
• Acceptance date: 2019-08-10
• DOI: 10.1002/mrm.27979
• EISSN: 1522-2594
• ISSN: 0740-3194
• Language: English
• Keywords: dynamic angiography; compressed sensing; vessel-encoded ASL; arterial spin labelling; radial golden angle