The clinical magnetocardiographer in Ulm

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 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.