System and method for robust flow measurements in vessels

1 . An apparatus for flow measurements in a vessel, comprising a processor configured to:

obtain a first ultrasound signal and a second ultrasound signal from an ultrasound transducer of an interventional device, wherein the ultrasound transducer is positioned at a location within the vessel and generates a plurality of ultrasound pulses,

wherein the first ultrasound signal is associated to ultrasound echoes that reflect from a first location (z 1 ) within the vessel in response to the plurality of ultrasound pulses, and the second ultrasound signal is associated to ultrasound echoes that reflect from a second location (z 2 ) within the vessel in response to the plurality of ultrasound pulses, wherein the first location and the second location are separate from the location of the ultrasound transducer,

wherein a first distance interval is between the first location and the location of the ultrasound transducer, and a second distance interval is between the second location and the location of the ultrasound transducer,

wherein the first distance interval and the second distance interval are spatially aligned along an ultrasound transmission and/or reception axis of the ultrasound transducer;

determine a first flow parameter at the first location based on the first ultrasound signal, and a second flow parameter at the second location based on the second ultrasound signal;

determine a composite flow parameter based on the first flow parameter and the second flow parameter; and

output, to a user interface, the composite flow parameter.

2 . The apparatus of claim 1 , wherein the first distance interval second distance interval are adjacent distance intervals along the ultrasound transmission and/or reception axis of the ultrasound transducer.

3 . The apparatus of claim 1 , wherein the first and second distance interval partially overlap.

4 . The apparatus of claim 1 , wherein the first flow parameter and the second flow parameter individually comprise at least one of a Doppler magnitude spectrum, a Doppler power spectrum, an instantaneous peak velocity, and an average peak velocity.

5 . The apparatus of claim 1 , wherein the processor is configured to determine the composite flow parameter based on a first weighting factor applied to the first flow parameter and a second weighting factor applied to the second flow parameter.

6 . The apparatus of claim 5 , wherein the first and second weighting factors are ascertained automatically by the processor.

7 . The apparatus of claim 6 , wherein the weighting factors are ascertained based on correlation among the Doppler magnitude spectra for the respective distance intervals, preferably based on optimization by using minimum variance of the combined Doppler magnitude spectrum over the distance intervals.

8 . The apparatus of claim 6 , wherein the weighting factors are ascertained based on the gradient of the Doppler magnitude spectra for the respective distance intervals.

9 . The apparatus of claim 6 , wherein the processor is configured to receive position and/or orientation information of the ultrasound transducer with respect to an anatomy of the vessel for which the flow measurement is performed, wherein the position and/or orientation information defines the ultrasound transmission and/or reception axis of the ultrasound transducer, and

wherein the processor is further configured to ascertain the first and second weighting factors based on the position and/or orientation information.

10 . The apparatus of claim 1 , wherein processor is configured to determine the composite flow parameter based on an average of Doppler magnitude spectra after scaling individual ones of the Doppler magnitude spectra for the first distance interval and the second distance interval such that noise floor values over the first distance interval and the second distance interval are brought to substantially equal values.

11 . The apparatus of claim 1 , wherein determining the composite flow parameter includes (i) determining a geometric mean of the first flow parameter and the second flow parameter, and/or (ii) determining an average of the first flow parameter and the second flow parameter.

12 . A system for flow measurements in a vessel, comprising:

a processor configured to:

obtain a first ultrasound signal and a second ultrasound signal from an ultrasound transducer of an interventional device, wherein the ultrasound transducer is positioned at a location within the vessel and generates a plurality of ultrasound pulses, wherein the first ultrasound signal is associated to ultrasound echoes that reflect from a first location (z 1 ) in response to the plurality of ultrasound pulses, and the second ultrasound signal is associated to ultrasound echoes reflect from a second location (z 2 ) in response to the plurality of ultrasound pulses, wherein the first location and the second location are separate from the location of the ultrasound transducer,

wherein a first distance interval is between the first location and the location of the ultrasound transducer, and a second distance interval is between the second location and the location of the ultrasound transducer,

wherein the first distance interval and the second distance interval are spatially aligned along an ultrasound transmission and/or reception axis of the ultrasound transducer;

ascertain a first flow parameter at the first location based on the first ultrasound signal, and a second flow parameter at the second location based on the second ultrasound signal;

ascertain a composite flow parameter based on the first flow parameter and the second flow parameter; and

output, to a user interface, the composite flow parameter;

the interventional device including the ultrasound transducer on a distal portion of the interventional device; and

the user interface for outputting the composite flow parameter.

13 . A method of flow measurement in a vessel, comprising:

obtaining a first ultrasound signal and a second ultrasound signal from an ultrasound transducer of an interventional device, wherein the ultrasound transducer is positioned at a location within the vessel and generates a plurality of ultrasound pulses,

wherein the first ultrasound signal is associated to ultrasound echoes that reflect from a first location (z 1 ) within the vessel in response to the plurality of ultrasound pulses, and the second ultrasound signal is associated to ultrasound echoes that reflect from a second location (z 2 ) within the vessel in response to the plurality of ultrasound pulses, wherein the first location and the second location are separate from the location of the ultrasound transducer,

wherein a first distance interval is between the first location and the location of the ultrasound transducer, and a second distance interval is between the second location and the location of the ultrasound transducer,

wherein the first distance interval and the second distance interval are spatially aligned along an ultrasound transmission and/or reception axis of the ultrasound transducer;

determining a first flow parameter at the first location and a second flow parameter at the second location based on the first and second ultrasound signals, respectively;

determining a composite flow parameter based on the first flow parameter and the second flow parameter; and

outputting, to a user interface, the composite flow parameter.