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The authors describe a method for accurate in vivo multislice imaging of the active component of the B1 field which is based on a previously proposed method, which uses the signal intensity ratio of two images measured with different excitation angles, and a repetition time TR 5 > or = 5 T1. The new method essentially reduces repetition and scan time by(More)
The report describes a method of impedance cardiography using an improved estimate of thoracic volume. The formulas and their implementation in hardware and software are explained and new shortband electrodes are described which generate a good homogeneous thoracic field. Examples of stroke volume and cardiac output curves underline the capabilities of the(More)
PURPOSE To demonstrate the technical feasibility and precision of a navigated diffusion-weighted (DW) MR imaging method with interleaved echo-planar imaging and test its diagnostic sensitivity for detection of ischemic stroke. MATERIALS AND METHODS Apparent diffusion coefficient (ADC) measurements were performed in phantoms, and six healthy adult(More)
Finite Element Method (FEM) using 26-node isoparametric finite elements was applied for modeling saddle-shaped head coils used in Magnetic Resonance Imaging (MRI) generating linearly polarized radiofrequency (RF) pulses at 64 MHz. The human head was modeled from MR scans of a volunteer and additional information were taken from Atlas of Sectional Human(More)
A new method and apparatus for non-disruptive blood pressure (BP) recording in the finger based on the vascular unloading technique is introduced. The instrument, in contrast to intermittent set point readjustments of the conventional vascular unloading technique, delivers BP without interruptions, thus refining the Penáz' principle. The method is based on(More)
The analytic solution of the harmonic downward continuation of the scalp potential field in an N-shell heterogeneous, but isotropic, spherical volume conductor model has been derived. The objective of this paper was to investigate the realization of a so-called "high-resolution electroencephalogram (EEG)": by enhancing the poor spatial resolution of EEG(More)
In this paper we present a study of spline surface Laplacian (LP), linear estimation (LE) and analytical deblurring (AD) utilized to improve the spatial resolution of single trial EEG data. AD is a method to reconstruct the potential distribution on the cortical surface. The dependency of AD on the electrode grid size as well as the sensitivity to(More)
The fact that time-varying magnetic fields cause eddy currents in conductive objects is very well known. Switched magnetic gradient fields, used in echo planar imaging, were shown in the past to be able to elicit a stimulation process in peripheral nerves. We report about the distribution and values of induced current densities in the human torso, modeled(More)
  • B Tilg, P Wach
  • 1995
A simulation study on magnetic source imaging within the human brain from a synthetic evoked magnetic field is presented. An inhomogeneous boundary element (BE) head model (cortex cerebrospinal fluid) was built up from real magnetic resonance imaging (MRI) cross-sections. In the forward problem, one or two rotating primary current dipoles (PCDs) are located(More)