K-space filter effect in three-dimensional contrast MR angiography

Abstract

Purpose: In three-dimensional (3-D) contrast MR angiography, temporal misregistration between the data acquisition period and the arrival of the contrast agent in the target vessels is thought to degrade the quality of the reconstructed images. The purpose of this study was to demonstrate and investigate this effect in phantom experiments.

Material and Methods: MR images of a phantom tube were evaluated with flowing materials of water or Gd-DTPA solution by changing from water to Gd-DTPA solution halfway through the data acquisition period.

Results: While no signal could be acquired with a stream of water in the tube, a clear signal was obtained with a flow of Gd-DTPA solution. Blurring and ghost artifacts surrounding the tube along the phase-encoding direction were observed when the flowing material was changed from water to Gd-DTPA solution halfway through the data acquisition period.

Conclusion: K-space filter effect occurs during 3-D contrast MR angiography owing to the transient passage of the contrast agent, and this effect causes spatial artifacts in the reconstructed images.