Program Information
Investigating the Resistance of GS-BSSFP to Motion Artifacts
M Hoff1*, J Andre2 , Q Xiang3 , (1) University of Washington, Seattle, WA, (2) University of Washington, Seattle, Washington, (3) University of British Columbia, Vancouver, British Columbia
Presentations
TU-H-206-5 (Tuesday, August 2, 2016) 4:30 PM - 6:00 PM Room: 206
Purpose: In addition to correcting magnetic field inhomogeneity-induced banding artifacts in balanced steady state free precession (bSSFP) MRI, preliminary in vivo studies indicate that the geometric solution (GS) also mitigates motion artifacts. The purpose here is to investigate the source of motion artifact correction through simulations, to further ascertain GS-bSSFP’s clinical potential.
Methods: Four bSSFP MR images with Δθ = 0°, 90°, 180°, and 270° respective phase cycling and TE/TR = 4.2/2.1ms were 1) acquired in vivo with a 3D axially-oriented sequence on a Philips Ingenia 3T MRI scanner using a flip angle α = 30°, and 180/180/120 matrix size and 1.0/1.0/1.0mm voxel size along frequency/phase/slice directions, and 2) simulated using α = 80°, parameters varied across the field-of-view (T1 relaxation = 200->3000ms, T2 relaxation = 40->3000ms, and field inhomogeneity θ = –π->+π), and added zero-mean Gaussian noise. The GS (the cross-point of lines/spokes connecting alternating phase cycles in the complex plane) and complex sum (CS) were computed pixel-by-pixel. Simulated data noise was reoriented in each associated spoke’s frame of reference in order to derive the noise radiality. Plots were then generated of GS and CS error and deviation as a function of the noise radiality in the original data.
Results: In vivo data indicates that the GS mitigates motion artifacts relative to the CS in the foramen magnum region. Simulated data indicates that the GS has less error in size and deviation than the CS, and this discrepancy grows as noise radiality increases.
Conclusion: The GS shows more accuracy than the CS in all tests executed, especially as phase-cycled image noise radiality increases. This implies that noise-like image artifacts such as those caused by motion and flow are suppressed by the GS, inspiring clinical applications of GS-bSSFP given its additional elimination of banding artifacts.
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