Rapid passive MR catheter visualization for endovascular therapy using nonsymmetric truncated k-space sampling strategies.
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.
Peng
Haidong
H
Department of Radiology, University of Calgary, Calgary, Alberta, Canada.
Draper
Jonathan N
JN
Frayne
Richard
R
D000465:Algorithms; D000818:Animals; D002406:Catheterization, Peripheral / Q000295:instrumentation*; D003198:Computer Simulation; D004285:Dogs; D005240:Feasibility Studies; D005263:Femoral Artery; D007089:Image Enhancement; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*