Digital signal processing aids cholesterol plaque detection

We describe four new methods for detection of cholesterol plaque deposits inside arteries, using digital signal processing. These methods have been tested on a number of patients. The results obtained are presented and discussed. An ultrasonic beam is directed towards the examined artery. Signal features obtained from the Doppler signal reflected from the bloodstream contain information about the character of turbulences caused by cholesterol deposits inside the artery. These features can thus provide information about the size, shape, and position of stenosis. Features in both the time and frequency domains were utilized, such as the LPC cepstrum, the exponential time-frequency distribution, the energy waveform and the wavelet transform