Synchronized multiple image tomographic cardiography

摘要

A scan converter storage surface is divided into image spaces corresponding to different points in the heart cycle. Ultrasound echoes from heart structures are plotted in the image spaces by means of special x, y sweeps which are offset to the image spaces by timing circuitry. Separate delay and spacing counters allow the first image to be stored at one interval after detection of the ECG R-wave and successive images to be stored at a another uniform interval. An ECG trace is stored in the first image space with cursors indicating the selected image timing. The scan converter is read out to a TV display. During image build-up, the read and write modes alternate. If desired, the TV sweeps to the scan converter may be attenuated and offset to display a single stored image. Images displayed in sequence provide animation. A self test circuit substitutes a fake ECG and writes bars in the scan converter image spaces using TV sweeps for the scan sweeps. The timing circuitry for the normal images gates the video for the bars. All of the timing for the system is derived from a TV composite sync signal and the patient's ECG current.