Event-synchronous cancellation of the heart interference in biomedical signals.

A two-pass adaptive filtering algorithm is proposed for cancellation of recurrent interferences such as the heart interference in biomedical signals. In the first pass, an average waveform in one period of the interference is estimated by event-synchronous (QRS-synchronous) averaging of the corrupted signal. In a second pass, an adaptive Schur recursive least squares (RLS) lattice filter is used to cancel the interference by using the event synchronously repeated estimated average waveform of the interference as an artificial reference signal.

[Roentgen image of the trachea in the supine position in substernal struma: a further possibility in avoiding radioiodine diagnosis].

It is recommended in substernal struma in the X-ray picture of the trachea prior to the X-ray picture in sitting position to make an X-ray picture in lying position, when the substernal part of the struma is not unequivocally to be seen in the 99mTc scintigram. Thus in many cases the discrepancy may be clarified and the radioiodine diagnostics be avoided.