Method for rapid MRI needle tracking

✍ Scribed by Eyal Kochavi; Dorith Goldsher; Haim Azhari

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 377 KB
• Volume: 51
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.20065

✦ Synopsis

Abstract

A new method for MRI needle tracking within a given two‐dimensional (2D) image slice is presented. The method is based on k‐space investigation of the difference image between the current dynamic frame and a reference frame. Using only a few central k‐lines of the difference image and a nonlinear optimization procedure, one can resolve the parameters that define the 2D sinc function that best characterizes the needle in k‐space. The spatial location and orientation of the needle are determined from these parameters. Rapid needle tracking is obtained by repeated acquisitions of the same set of several central k‐lines (as in a “keyhole” protocol) and repeated computation of these parameters. The calculated needle tip is depicted on the reference image by means of a graphic overlay. The procedure was tested in computer simulations and in actual MRI scans (the computations were done offline). It was demonstrated that six k‐lines out of 128 usually suffice to locate the needle. The refresh rate of the needle location depends on the time required to sample the subset of k‐lines, calculate the current needle location, and refresh the reference image. Magn Reson Med 51:1083–1087, 2004. © 2004 Wiley‐Liss, Inc.