Dynamic scan‐plane tracking using MR position monitoring

Abstract

An MR-based method for tracking subject motion is presented. The technique identifies subject motion from the three-dimensional positions of three small samples attached to the subject in a fixed, triangular configuration. The updated positions of these samples relative to their initial positions determine a rigid body transformation. Applied to the MRI scan prescription via adaptive feedback controls, this transformation yields an updated MRI scan plane that tracks the prescribed imaging section as the subject moves. The scan-plane tracking procedure is demonstrated experimentally for two-dimensional imaging of a standard imaging phantom and the head of a human subject. Sets of images were acquired sequentially, with motion (translations and/or rotations) introduced between image frames. The scan-plane tracking system provides well registered image slices of the same section, adaptively compensating for the subject motion.

SimPACE: Generating simulated motion corrupted BOLD data with synthetic-navigated acquisition for the development and evaluation of SLOMOCO: A new, highly effective slicewise motion correction

“…Volumetric correction for BOLD MRI was initially done in the early days of fMRI by adapting Roger Woods’ automated image registration (AIR) algorithm, originally developed for PET functional imaging studies(Woods et al, 1992). BOLD-specific methods, which were initially described nearly 20 years ago(Friston et al, 1995; Hajnal et al, 1994; Hajnal et al, 1995), have since undergone rapid development(Ardekani et al, 2001; Cox and Jesmanowicz, 1999; Derbyshire et al, 1998; Lee et al, 1998; Thesen et al, 2000), and have been implemented comparably(Ardekani et al, 2001; Morgan et al, 2007; Morgan et al, 2001; Oakes et al, 2005) across common MRI analysis packages(Cox, 1996; http://www.fil.ion.ucl.ac.uk/spm, ; Smith et al, 2004). These methods all rely on using small displacement approximations to produce an analytic solution (unlike the AIR method, which is an iterative, generalized method).…”

Real-Time Estimation of 3-D Needle Shape and Deflection for MRI-Guided Interventions

“…Methods in active tracking of devices in MRI environments [6], [11], [18], [37] are increasingly fast and accurate, yet these techniques, as reviewed in [7], have limitations in regard to line-of-sight, heating, sensitive tuning, complex calibration, and expense. Passive tracking methods [8] rely on observing the device and patient’s anatomy together with the use of bulky stereotactic frames or external fiducials [13], [21].…”

System for MR Image–guided Prostate Interventions: Canine Study

“…Three fiducial microcoils, each connected to a separate receiver channel, were integrated within the transrectal needle guide. To determine the position and orientation of these coils, we obtained 12 one-dimensional dodecahedrally spaced MR signal readouts (5.0/2.3 [repetition time msec/echo time msec], bandwidth of ±64 kHz, 1° flip angle, 40-cm field of view, 256 readout points), allowing for coil localization, as described previously (20,21). MR signal acquisition for coil localization took approximately 60 milliseconds.…”