Ringdown Suppression for a Sonothrombolysis Catheter Using Principal Component Analysing Filtering

Therapeutic ultrasound catheters emit high pressure, low frequency, long cycle waveforms that are poorly suited for imaging. However, in the context of sonothrombolysis treatment, it would be advantageous for these catheters to perform real-time, in situ, treatment monitoring. An impediment to this goal is the ringdown artifact that extends for several microseconds in the pulse-echo RF data and obscures the signal derived from nearby tissue structures and the thrombus. In this study, we present preliminary results of a principal-component based filter that separates ringdown from tissue-derived signals and permits the analysis of a decorrelation-based metric of clot erosion. The method is demonstrated using an EkoSonic therapeutic ultrasound catheter in an in vitro blood clot dissolution model.