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Magnetic resonance is an exceptionally powerful and versatile measurement technique. The basic structure of a magnetic resonance experiment has remained largely unchanged for almost 50 years, being mainly restricted to the qualitative probing of only a limited set of the properties that can in principle be accessed by this technique. Here we introduce an(More)
PURPOSE To evaluate an augmented reality (AR) system in combination with a 1.5-T closed-bore magnetic resonance (MR) imager as a navigation tool for needle biopsies. MATERIALS AND METHODS The experimental protocol had institutional animal care and use committee approval. Seventy biopsies were performed in phantoms by using 20 tube targets, each with a(More)
PURPOSE To determine whether consistent regions of activity could be observed in the lumbar spinal cord of single subjects with spin-echo functional MRI (fMRI) if several repeated experiments were performed within a single imaging session. MATERIALS AND METHODS Repeated fMRI experiments of the human lumbar spinal cord were performed at 1.5 T with a(More)
We investigated the feasibility of using echo-shifted fast low-angle shot (FLASH) for temperature-monitored thermo-therapeutic procedures in a 0.2 T interventional magnetic resonance (MR) scanner. Based on the proton resonance frequency shift technique, modified echo-shifted FLASH has sufficiently high signal-to-noise ratio to provide accurate temperature(More)
PURPOSE Our goal was to determine whether functional MRI on a standard 1.5 T system can localize activation during a visual vigilance sustained attention task and whether this corresponds to results described in a PET investigation of a similar task. METHOD Sixteen volunteers were studied on a 1.5 T system using a gradient echo technique. A single axial(More)
OBJECTIVE This study examined the contribution and interdependence of multiple imaging parameters in clinical imaging sequences to aid practicing radiologists in minimizing artifacts during MR imaging of the spine after implantation of titanium pedicle screws. MATERIALS AND METHODS A lumbar spine specimen with titanium pedicle screws implanted in the(More)
Clinical requirements for interventional MRI (I-MRI) monitoring of needle placement or thermal ablation demand rapid (near-real-time) image acquisition rates, high spatial resolution, and T2 weighting. Experimental analysis performed earlier suggests that many sequences used for either rapid scanning or T2 weighting at high fields fail to meet both the(More)
A technique has been developed that significantly improves the image resolution and reduces motion artifacts in conventional two-dimensional Fourier transform and three-dimensional Fourier transform magnetic resonance imaging sequences. Modifications on the gradient waveforms completely refocus the transverse magnetization at the echo time, regardless of(More)