Purpose
We hypothesized that high undersampling factors could be used in conjunction with radial Quiescent-Inflow Single-Shot (QISS) MRA in order to accelerate the data acquisition and enable multi-slice acquisitions.
Methods
Seven subjects were imaged on a 1.5T MRI system. For multi-slice QISS MRA, the venous saturation RF pulse, in-plane saturation RF pulse, and QI were applied only once prior to the first slice.
Results
The mean (standard deviation) measurements for the intra-arterial signal-to-noise ratio were: 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); Radial 3 slices, 32 views - 21.7(3.9), normalized for pixel size to 15.8. Horizontal striping was present with multi-slice radial QISS MRA (especially with the 3-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.
Conclusion
Very high undersampling factors in excess of 18 have been demonstrated for nonenhanced MRA using a radial QISS technique, enabling the acquisition of 2 to 3 slices per cardiac cycle. Scan time for a complete peripheral MRA could be shortened to 2 minutes or less.
With modern cross-sectional imaging techniques, cystic lesions are very common and usually incidental findings, especially if small. However, when cysts enlarge, become infected, bleed, or undergo torsion, they can be symptomatic, and percutaneous drainage can be effective in the management. When cysts recur after aspiration, which is often the case for hepatic and renal cysts, cyst sclerosis or surgical unroofing may be required. This article describes the indications for and technical aspects of percutaneous sclerotherapy of cystic lesions of multiple organ systems.
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