S.N. Erne

Publications of S.N. Erne

• Open magnetic and electric graphic analysis

  Authors: H.-P. Muller, I. Decesaris, M. Demelis, L. Marzetti, A. Pasquarelli, S.N. Erne, A.C. Ludolph, J. Kassubek

  Engineering in Medicine and Biology Magazine, IEEE. 06/2005;

  In this article, a novel analysis technique, open magnetic and electric graphic analysis (OMEGA), is described and is applied to combine MEG and fMRI measurements in a motor task. The study wasIn this article, a novel analysis technique, open magnetic and electric graphic analysis (OMEGA), is described and is applied to combine MEG and fMRI measurements in a motor task. The study was intended to demonstrate how, within OMEGA, the localization of brain activation can be complemented by integrated analysis of human multimodal functional (MEG, fMRI) and anatomical (MRI) measurements. The OMEGA software provides an analysis platform for user-independent, fast, and reproducible multimodal analysis in one single software environment. The implementation of OMEGA allows the analyst to receive comprehensive MEG/fMRI results in a matter of minutes after the measurements have been completed. With OMEGA, the clinical researcher gets comprehensive information in a quick and standardized approach about the sites and the time course of neurological activation, which is useful for clinical applications and diagnostics.

• An AC magnetizing field biosusceptometer using a SQUID based sensor with additional compensation module

  Authors: S. Della Penna, C. Del Gratta, F. Cianflone, S.N. Erne, C. Granata, A. Pentiricci, V. Pizzella, M. Russo, G.L. Romani

  Applied Superconductivity, IEEE Transactions on. 07/2003;

  We present a new SQUID based susceptometer for liver iron concentration (LIC) assessment. The instrument is operated with an inhomogeneous AC magnetizing field. The susceptometer is based on 7We present a new SQUID based susceptometer for liver iron concentration (LIC) assessment. The instrument is operated with an inhomogeneous AC magnetizing field. The susceptometer is based on 7 channels, each consisting of a sensing unit and of an additional unit for the compensation of the applied field residual and its variation. Each unit is a second order gradiometer and is coupled to a dc SQUID with a parallel washer configuration. The compensation module output is digitally processed and coupled to the sensing gradiometer by means of an additional feedback path. The estimation of LIC is based on a numerical model of the subject's torso obtained from the segmentation of ultrasound images.

• New methods in fMRI analysis

  Authors: H.-P. Muller, E. Kraft, A. Ludolph, S.N. Erne

  Engineering in Medicine and Biology Magazine, IEEE. 10/2002;

  Hierarchical cluster analysis improves signal-to-noise ratio compared to standard techniques. In this work we present a new approach for improving the SNR in fMRI. The special implementation of theHierarchical cluster analysis improves signal-to-noise ratio compared to standard techniques. In this work we present a new approach for improving the SNR in fMRI. The special implementation of the voxel-based motion-correction algorithms allows for very fast and precise correction of head movements in the frame of the selected model. The hierarchical cluster analysis has proven to be a useful tool for the increase of the SNR of the functional results. As these tools and established deterministic and statistical functional analysis tools are implemented in one software platform (FAMIS), direct comparison between the results becomes feasible. As each analysis result can be obtained within seconds and the user can switch between the display for the different results, direct comparison between the methods can be performed. Deterministic analysis leads to an activation concept that is independent from the noise level, and vice versa the statistical analysis leads to an activation concept where the activation is intended as deviation from noise and in such way the activation becomes related to the noise level. The deterministic methods exclude true positive results with increasing noise, and the statistical methods include false positive results with increasing noise. Nevertheless, the decision regarding which of the methods should be the method of choice for fMRI analysis is not the subject of this work.

• High-resolution ECG analysis platform with enhanced resolution

  Authors: D.E. Ritscher, S.N. Erne, H.G. Kammrath, V. Hombach, M. Hoher

  Computers in Cardiology 1997; 10/1997

  A need was seen for a platform to provide a common starting basis for numerous analyses, so that these results could be meaningfully compared. Since the effectiveness of many algorithms is dependentA need was seen for a platform to provide a common starting basis for numerous analyses, so that these results could be meaningfully compared. Since the effectiveness of many algorithms is dependent on the start point of the analysis, a system was developed to ensure robust, consistent and exact base parameter estimation. This system is the core of numerous analysis studies in the department of cardiology. It first calculates and stores basic parameters needed for subsequent analyses. The most important parameter is the beat alignment point, since degradation of this trigger reduces the resolution of these analyses. Improvements to trigger estimation are described. Two features are particularly important to further analyses: 1. All analysis is based on these stored core parameters, making it possible to validly compare results front, for example, a spectral analysis with a time-domain analysis. 2. Detailed control of an analysis is possible, including specifying which beats are included in the analysis

• Magnetocardiography and exercise testing: data acquisition and data processing

  Authors: K. Brockmeier, S. Comani, S.N. Erne, C. De Gratta, S. Di Luzio, A. Pasquarelli, G.L. Romani

  Computers in Cardiology 1991, Proceedings.; 10/1991

  Sixteen healthy male subjects underwent magnetocardiography during physical exercise. A specific signal averaging technique was developed because the quality of the magnetic signals exceeded that ofSixteen healthy male subjects underwent magnetocardiography during physical exercise. A specific signal averaging technique was developed because the quality of the magnetic signals exceeded that of the electrocardiographic signals, particularly regarding baseline shifting. Significant ST segment displacements of the magnetic signal were found during exercise at a heart rate of 120 bpm ( p <0.001). No significant ST segment changes were found in the electrocardiographic map, which consisted of an array of 16 precordial electrodes, simultaneously recorded. The hypothesis that junctional ST segment displacements can be detected earlier with the magnetocardiogram is discussed

• The geomagnetic field: a factor in cellular interactions? I. Magnetism and Schwann cell-axon interaction in the peripheral nerves of the newborn rat.

  Authors: K Shibib, M Brock, G Gosztonyi, S N Erne, H D Hahlbohm, G Schoknecht

  Neurological research. 01/1988; 9(4):225-35.

  Axonal ensheathment and myelination, one form of axon-sheath cell interaction, was studied under normal earth magnetism, in the absence of terrestrial magnetic field, and under a 5 G (0.0005 T)Axonal ensheathment and myelination, one form of axon-sheath cell interaction, was studied under normal earth magnetism, in the absence of terrestrial magnetic field, and under a 5 G (0.0005 T) magnetic field. Results indicate that the geomagnetic field is necessary for the fundamental biological activity of axonal ensheathment and myelination. The exact mechanism of action remains obscure.

• Study of P-R Segment Using Magnetocardiographic Measurement

  Authors: Y. Uchikawa, M Kotani, S. N. Erne

  Magnetics in Japan, IEEE Translation Journal on. 10/1987; 2(9):851-852.

  Magnetocardiographic measurement and analysis of P-R segments were studied using a SQUID fluxmeter in a PTB high performance magnetically shielded room. It was found that auricle depolarization andMagnetocardiographic measurement and analysis of P-R segments were studied using a SQUID fluxmeter in a PTB high performance magnetically shielded room. It was found that auricle depolarization and repolarization processes could be clearly distinguished by the difference in polarity on the equivalent magnetic field distribution, and the equivalent potential difference distribution maps. This confirmed that performing analysis of PR segments makes a valuable contribution to research on cardiomagnetism.

• Theory of rf‐biased superconducting quantum interference device for nonhysteretic regime

  Authors: S. N. Erne, H.‐D. Hahlbohm, H. Lubbig

  Journal of Applied Physics. 01/1977;

  The SQUID response ϕ (ϕ e ) is studied analytically for the nonhysteretic regime, 2πL s I c ≪ϕ 0 , and low‐frequency excitation, ω?10⁸ s^-1. The influence of the weak‐linkThe SQUID response ϕ (ϕ e ) is studied analytically for the nonhysteretic regime, 2πL s I c ≪ϕ 0 , and low‐frequency excitation, ω?10⁸ s^-1. The influence of the weak‐link parameters on the voltage at the tank circuit is demonstrated. The calculations including the cos(2πϕ/ϕ 0 ) term are compared with the experimental results of Nisenoff and Wolf.

• Designing Multichannel Sensor Arrays for Biomagnetism

  Authors: S.N. Erne, J. Edrich

  Engineering in Medicine and Biology Society, 1992. Vol.14. Proceedings of the Annual International Conference of the IEEE;

  Not Available

• Tissue segmentation of MRI of the head by means of a Kohonen map

  Authors: S. Congorto, S.D. Penna, S.N. Erne

  Engineering in Medicine and Biology Society, 1996. Bridging Disciplines for Biomedicine. Proceedings of the 18th Annual International Conference of the IEEE;

  The authors developed a new method in order to automatically segment magnetic resonance images (MRIs) of the head. The main tissues, such as scalp, brain and skull, are recognised. The method isThe authors developed a new method in order to automatically segment magnetic resonance images (MRIs) of the head. The main tissues, such as scalp, brain and skull, are recognised. The method is based on a Kohonen self organising feature map which performs a cluster of the image areas into three main classes. The network, after being trained, is successfully operated on the test set. The network performances do not depend on the MRI apparatus producing the images set. The network classes are properly matched and processed in order to obtain slices containing the desired tissues. The proposed method has been developed in the frame of a project for the 3-dimensional reconstruction of selected surfaces

• The clinical magnetocardiographer in Ulm

  Authors: S.N. Erne, K. Torquati, S. Della Penna, A. Pasquarelli, C. Granata, R. Rossi

  Engineering in Medicine and Biology Society, 1998. Proceedings of the 20th Annual International Conference of the IEEE;

  We present a magnetocardiographic system developed in the framework of an international cooperation and installed at the University of Ulm. The system design is conceived for clinical and routineWe present a magnetocardiographic system developed in the framework of an international cooperation and installed at the University of Ulm. The system design is conceived for clinical and routine use. The main sensor consists of a hexagonal 55 channels planar system with dc SQUID magnetometers contained in a low noise dewar. Nineteen reference channels are used to form software gradiometers. The patient handling setup and the dewar support are designed to easily allow the positioning procedure and the interaction with the patient. The sensor is operated in a high quality magnetically shielded room made of three soft magnetic metal layers and an external aluminum layer. The low frequency performances can be enhanced by means of an active compensation technique. A set of biopreamplifiers for 128 channels BSPM measurements is included. The data acquisition system allows to perform MCG and BSPM measurement simultaneously with sampling frequencies up to 10 kHz. All basic preprocessing, bandpass filtering, decimation and noise compensation are performed on the fly using an array of DSPs. The data analysis session provides both time domain approach and source identification approach. Direct integration of the results with CT or MRI data is also available