Rapid passive MR catheter visualization for endovascular therapy using nonsymmetric truncated k-space sampling strategies
- 作者：Haidong Peng ; Jonathan N. Draper ; Richard Frayne
- 关键词：Endovascular MR ; Passive visualization and tracking ; Nonsymmetric truncated k-space data ; Zero filling ; Projection-onto-convex sets
- 刊名：Magnetic Resonance Imaging
- 出版年：2008
- 期刊代码：188_0730725x
- 类别：med
- 出版时间：April 2008
- 卷：26
- 期：3
- 页码：293-303
- 文件大小：1352 K
摘要
Passive catheter tracking guidance by MRI is a promising approach for endovascular therapy that may have several clinical advantages over the more frequently employed active MR approaches. However, real-time MR passive tracking is problematic because it is difficult to have an image update rate >1 Hz and preserve adequate spatial and image contrast resolution. One solution for improving real-time temporal performance is the use of nonsymmetric truncated k-space sampling strategies, which acquire only a fraction of the data in both the readout and phase-encoding directions. This article investigated these acquisition strategies in combination with using (a) multicycle projection dephaser (mcPD) gradients for background suppression and (b) the projection-onto-convex sets (POCS) algorithm to reconstruct the images. The use of mcPD gradients allowed the data sampling strategies to exploit the k-space energy structure of the catheter, and POCS allowed reconstruction of high-quality MR images that were suitable for real-time passive catheter tracking and demonstrated improved geometric representations of catheter width and tip position compared to zero filling. The use of nonsymmetric truncated k-space reduced the total acquisition time.