scholarly journals The advantages of radial trajectories for vessel-selective dynamic angiography with arterial spin labeling

2019 ◽  
Author(s):  
Eleanor S. K. Berry ◽  
Peter Jezzard ◽  
Thomas W. Okell
Keyword(s):  
Arterial Spin Labeling ◽  
Parallel Imaging ◽  
Spin Labeling ◽  
Dynamic Imaging ◽  
Calibration Data ◽  
Time Resolved ◽  
High Acceleration Factor ◽  
High Acceleration ◽  
Snr Efficiency ◽  
Rule Out

AbstractObjectTo demonstrate the advantages of radial k-space trajectories over conventional Cartesian approaches for accelerating the acquisition of vessel-selective arterial spin labeling (ASL) dynamic angiograms, which are conventionally time-consuming to acquire.Materials and MethodsVessel-encoded pseudocontinuous ASL was combined with time-resolved balanced steady-state free precession (bSSFP) and spoiled gradient echo (SPGR) readouts to obtain dynamic vessel-selective angiograms arising from the four main brain-feeding arteries. Dynamic 2D protocols with acquisition times of one minute or less were achieved through radial undersampling or a Cartesian parallel imaging approach. For whole-brain dynamic 3D imaging, magnetic field inhomogeneity and the high acceleration factors required rule out the use of bSSFP and Cartesian trajectories, so the feasibility of acquiring 3D radial SPGR angiograms was tested.ResultsThe improved SNR efficiency of bSSFP over SPGR was confirmed for 2D dynamic imaging. Radial trajectories had considerable advantages over a Cartesian approach, including a factor of two improvement in the measured SNR (p<0.00001, N=6), improved distal vessel delineation and the lack of a need for calibration data. The 3D radial approach produced good quality angiograms with negligible artifacts despite the high acceleration factor (R=13).ConclusionRadial trajectories outperform conventional Cartesian techniques for accelerated vessel-selective ASL dynamic angiography.

scholarly journals Partial volume correction of brain perfusion estimates using the inherent signal data of time-resolved arterial spin labeling

2014 ◽  
Vol 27 (9) ◽  
pp. 1112-1122 ◽  
Author(s):  
André Ahlgren ◽  
Ronnie Wirestam ◽  
Esben Thade Petersen ◽  
Freddy Ståhlberg ◽  
Linda Knutsson
Keyword(s):  
Arterial Spin Labeling ◽  
Brain Perfusion ◽  
Spin Labeling ◽  
Partial Volume Correction ◽  
Time Resolved ◽  
Partial Volume ◽  
Volume Correction

scholarly journals Highly Accelerated Vessel-Selective Arterial Spin Labelling Angiography using Sparsity and Smoothness Constraints

2019 ◽  
Author(s):  
Sophie Schauman ◽  
Mark Chiew ◽  
Thomas W. Okell
Keyword(s):  
Image Quality ◽  
Compressed Sensing ◽  
Arterial Spin Labeling ◽  
Parallel Imaging ◽  
Spin Labeling ◽  
Dominant Factor ◽  
Image Domain ◽  
In Vivo Experiments ◽  
Scan Time

AbstractPurposeTo demonstrate that vessel-selectivity in 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.MethodsSimulations 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 both image domain sparsity and temporal smoothness on the angiograms in a parallel imaging and compressed sensing framework.ResultsRelative 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.ConclusionThe increase in relative sparsity of vessel-selective angiograms compared to non-selective 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.

scholarly journals Time-resolved Vessel-selective Digital Subtraction MR Angiography of the Cerebral Vasculature with Arterial Spin Labeling

Radiology ◽  
2010 ◽  
Vol 257 (2) ◽  
pp. 507-515 ◽  
Author(s):  
P. M. Robson ◽  
W. Dai ◽  
A. Shankaranarayanan ◽  
N. M. Rofsky ◽  
D. C. Alsop
Keyword(s):  
Arterial Spin Labeling ◽  
Mr Angiography ◽  
Spin Labeling ◽  
Digital Subtraction ◽  
Cerebral Vasculature ◽  
Time Resolved

3D time-resolved vessel-selective angiography based on pseudo-continuous arterial spin labeling

2015 ◽  
Vol 33 (6) ◽  
pp. 840-846 ◽  
Author(s):  
Thomas Lindner ◽  
Ulf Jensen-Kondering ◽  
Matthias J.P. van Osch ◽  
Olav Jansen ◽  
Michael Helle
Keyword(s):  
Arterial Spin Labeling ◽  
Spin Labeling ◽  
Selective Angiography ◽  
Time Resolved ◽  
Continuous Arterial Spin Labeling

scholarly journals Time-Resolved High-Resolution Angiography Combining Arterial Spin Labeling and Time-of-Flight Imaging

2020 ◽  
Author(s):  
Thomas Lindner ◽  
Olav Jansen ◽  
Michael Helle
Keyword(s):  
Magnetic Resonance ◽  
High Resolution ◽  
Spatial Resolution ◽  
Arterial Spin Labeling ◽  
Time Of Flight ◽  
Spin Labeling ◽  
Arterial System ◽  
Venous Flow ◽  
Time Resolved ◽  
Time Of Flight Imaging

Abstract A strategy to combine two non-contrast-enhanced magnetic resonance angiography techniques is presented. It is based on arterial spin-labeled magnetic resonance imaging to visualize the arterial system at different time points to obtain information about hemodynamic properties in conjunction with a high-resolution time-of-flight angiography acquisition. The temporal information obtained by arterial spin labeling (ASL) is combined with the highly spatial resolved time-of-flight image to obtain information about blood flow. Extracting the information of ASL and time-of-flight-imaging leads to images with high spatial resolution which also give information about the temporal course of blood through the intracerebral vasculature. Furthermore, owing to the properties of ASL, visible venous flow in the time-of-flight images can be suppressed. The behavior of vascular filling (i.e. signal changes in the ASL) is investigated and used for further interpretation of the data. Furthermore, the ASL data were down-sampled to find a minimally needed spatial resolution to combine both image types. Up to 1.6 mm isotropic resolution still showed satisfying results rated by two independent readers. In conclusion, a combination of these two different vascular imaging modalities allows to obtain highly spatial and time-resolved images.

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