Apparatus and method for detecting blood flow in intravascular ultrasonic imaging

An ultrasonic imaging system for constructing an image of a region within a vasculature indicative of blood flowing within the region, the ultrasonic imaging system comprising:

• a probe assembly including an ultrasound transducer assembly communicatively coupled to an image processing control unit for causing the ultrasound transducer assembly to repeat a plurality of times to obtain a set of echo waveforms:
• emitting an ultrasonic waveform from within a lumen of the vasculature, the ultrasonic waveform propagating through the region within the vasculature,
• sensing echoes of the emitted ultrasonic waveform arising from reflections of the ultrasonic waveform from tissue and blood within the region, and
• converting the sensed echoes of the emitted ultrasonic waveform into an echo waveform;
• an echo waveform processing unit, communicatively coupled to the image processing control unit, for receiving and combining the set of echo waveforms, in accordance with control signals transmitted by the image processing control unit, to form a modified echo waveform indicating areas within the region occupied by relatively dynamic features including flowing blood, the portions of the set of echo waveforms arising from relatively static features in the region, including tissue, being substantially attenuated in the modified echo waveform;
• and
• an ultrasound image processor for constructing a first image of the region of the vasculature from the modified echo waveform, the first image primarily representing relatively dynamic features in the region.