Fluid flow detection for ultrasound imaging devices, systems, and methods

An ultrasound imaging system, comprising:

• an intravascular imaging catheter comprising:
• a flexible elongate member configured to be positioned within a blood vessel of a patient heart;
• and
• a circumferential ultrasound transducer array coupled to the flexible elongate member, wherein the ultrasound transducer array is configured to obtain first signal data and second signal data associated with different imaging modes;
• and
• a processor configured for communication with the intravascular imaging catheter, and wherein the processor is configured to:
• generate, based on the first signal data, motion data representative of first motion and second motion, wherein the first motion is blood flow motion and the second motion is tissue motion, wherein the motion data comprises a plurality of vectors spatially distributed around the circumferential ultrasound transducer array, wherein each vector of the plurality of vectors comprises a plurality of samples representing a plurality of imaging depths away from the ultrasound transducer array;
• distinguish between the first motion and the second motion, wherein, to perform the distinguishing, the processor is configured to:
• determine, based on the first signal data, a respective average signal level for each imaging depth of the plurality of imaging depths;
• and
• apply the respective average signal level to each sample at a corresponding imaging depth in the plurality of vectors;
• generate structural data based on the second signal data, wherein the structural data represents the blood vessel;
• combine the motion data and the structural data to determine motion pixels and structure pixels forming an intravascular image, wherein the distinguishing and the determination of the motion pixels and structure pixels are distinct from one another;
• and
• output the intravascular image to a display in communication with the processor.