Thomas Grafendorfer

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A 16-channel receive-only, closely fitted array coil is described and tested in vivo for bilateral breast imaging at 3 T. The primary purpose of this coil is to provide high signal-to-noise ratio and parallel imaging acceleration in two directions for breast MRI. Circular coil elements (7.5-cm diameter) were placed on a closed "cup-shaped" platform, and(More)
PURPOSE To deploy clinically, a combined parallel imaging compressed sensing method with coil compression that achieves a rapid image reconstruction, and assess its clinical performance in contrast-enhanced abdominal pediatric MRI. MATERIALS AND METHODS With Institutional Review Board approval and informed patient consent/assent, 29 consecutive pediatric(More)
We describe the electronics for controlling the independently pulsed polarizing coil in a prepolarized magnetic resonance imaging (PMRI) system and demonstrate performance with free induction decay measurements and in vivo imaging experiments. A PMRI scanner retains all the benefits of acquiring MRI data at low field, but with the higher signal of the(More)
Introduction Prepolarized MRI (PMRI) [1,2] is an inexpensive MRI architecture that uses a mid-field copper wire magnet (B p) for longitudinal magnetization growth and a low-field magnet (B 0) for spatial encoding and data acquisition, as shown in Fig. 1. This setup offers the SNR of mid-field imaging combined with the benefits of low-field imaging, which(More)
Prepolarized MRI (PMRI) with pulsed electromagnets has the potential to produce diagnostic quality 0.5- to 1.0-T images with significantly reduced cost, susceptibility artifacts, specific absorption rate, and gradient noise. In PMRI, the main magnetic field cycles between a high field (B(p)) to polarize the sample and a homogeneous, low field (B(0)) for(More)
PURPOSE To design, construct, and validate a semiflexible 64-channel receive-only phased array for pediatric body MRI at 3T. METHODS A 64-channel receive-only phased array was developed and constructed. The designed flexible coil can easily conform to different patient sizes with nonoverlapping coil elements in the transverse plane. It can cover a field(More)
Q-spoiling is the process of decoupling an MRI receive coil to protect the equipment and patient. Conventionally, Q-spoiling is performed using a PIN diode switch that draws significant current. In this work, a Q-spoiling technique using a depletion-mode Gallium Nitride HEMT device was developed for coil detuning at both 1.5 T and 3 T MRI. The circuits with(More)
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