Quiescent-inflow single-shot magnetic resonance angiography using a highly undersampled radial k-space trajectory

We hypothesized that high undersampling factors could be used in conjunction with radial quiescent-inflow single-shot magnetic resonance angiography (MRA) to accelerate the data acquisition and enable multislice acquisitions.

Seven subjects were imaged on a 1.5 T MRI system. For multislice quiescent-inflow single-shot MRA, the venous saturation radiofrequency pulse, in-plane saturation radiofrequency pulse, and quiescent interval were applied only once before the first slice.

The mean (standard deviation) measurements for the intra-arterial signal-to-noise ratio were as follows: Cartesian 1 slice-29.3 (5.5); radial 1 slice, 92 views-22.3 (3.6); radial 1 slice, 46 views-18.5 (2.0); radial 2 slices, 46 views-18.3 (3.2); and radial 3 slices, 32 views-21.7 (3.9), normalized for pixel size to 15.8. Horizontal striping was present with multislice radial quiescent-inflow single-shot MRA (especially with the three-slice acquisition) due to variable T1 relaxation between the concurrently acquired slices, but the image quality remained diagnostic. Vascular pathology in patients with peripheral arterial disease was well shown by all techniques.

Very high undersampling factors in excess of 18 have been demonstrated for nonenhanced MRA using a radial quiescent-inflow single-shot technique, enabling the acquisition of two to three slices per cardiac cycle. Scan time for a complete peripheral MRA could be shortened to 2 min or less.