Medical doppler ultrasound system for locating and tracking blood flow

Abstract

Systems and methods for processing echo signals in a Doppler ultrasound system from a region of interest. An ultrasound beam is electronically steered to deliver ultrasound to and receive echo signals from a plurality of sample locations in the region of interest. The echo signals for each sample location are processed to extract Doppler shift signals and Doppler shift data representing the Doppler shift signals are generated. The Doppler shift data accumulated for the sample locations can be used to detect the presence of blood flow in the region of interest, and identify the location in the region of interest at which the presence of blood flow is detected. The blood flow can be tracked by updating the location of the detected blood flow in the region of interest. The blood flow can be further monitored by combining the locating and tracking functionality with an m-mode ultrasound image.

What is claimed is: 
     
         1 . A Doppler ultrasound system, comprising:
 a probe having a multi-element transducer including a plurality of transducer elements;   a transmitter circuit operably coupled to the transducer elements of the transducer and configured to generate respective drive signals for driving the transducer elements to deliver an ultrasound beam;   a receiver circuit operably coupled to the transducer elements of the transducer and configured to receive echo signals detected by the respective transducer elements and generate in response thereto echo data representing the echo signals; and   a processor operably coupled to the transmitter and receiver circuits and configured to control the transmit circuit in generating drive signals for the transducer elements and configured to process the echo data from the receiver circuit and extract therefrom Doppler shift signals represented by Doppler shift data, the processor further configured to process the Doppler shift data to locate blood flow in a region of interest and automatically calculate data representing a vector identifying the location of the blood flow in the region of interest.   
     
     
         2 . The Doppler ultrasound system of  claim 1  wherein the processor comprises a processor further configured to control the transmitter circuit to deliver ultrasound to the location of the blood flow in the region of interest in accordance with the vector, to receive echo signals from the location of the blood flow in the region of interest in accordance with the vector, and process the data from the receiver circuit to extract Doppler shift signals and generate Doppler shift data therefrom for the blood flow in the region of interest. 
     
     
         3 . The Doppler ultrasound system of  claim 1  wherein the processor comprises a processor further configured to control the transmitter circuit to deliver ultrasound to a plurality of sample locations over a region of interest, each location having a beam axis associated therewith, at least two different planes are defined in which two or more of the beam axes lie, the processor further configured to process the data from the receiver circuit to extract Doppler shift signals, generate Doppler shift data therefrom for each of the sample locations, and determine from the Doppler shift data for the sample locations the presence of blood flow in the region of interest. 
     
     
         4 . The Doppler ultrasound system of  claim 1  wherein the transmitter circuit comprises a plurality of transmit circuits, each transmit circuit operably coupled to a respective one of the transducer elements and configured to generate a drive signal for driving the respective transducer element. 
     
     
         5 . The Doppler ultrasound system of  claim 1  wherein the processor configured to locate blood flow in the region of interest comprises a processor configured to control the transmitter circuit to deliver ultrasound to a plurality of sample locations over the region of interest, the sample locations arranged spatially across a surface having a lateral extent in two-dimensions relative to a normal axis extending from the multi-element transducer, the processor further configured to process the data from the receiver circuit to extract Doppler shift signals and generate Doppler shift data therefrom for each of the sample locations, and configured to determine from the Doppler shift data accumulated for the sample locations the presence of blood flow in the region of interest. 
     
     
         6 . The Doppler ultrasound system of  claim 5  wherein the processor determines from the Doppler shift data accumulated for the sample locations the presence of blood flow in the region of interest by determining the power of the Doppler signals and identifying a location corresponding to a maximum calculated power in the region of interest. 
     
     
         7 . The Doppler ultrasound system of  claim 6  wherein the processor is further configured to calculate the power of the Doppler signals for the sample locations from the Doppler shift data by:
 constructing a covariance matrix for each of the sample locations; 
 calculating a respective ray defining a direction for each of the sample locations; 
 calculating a minimum variance power spectrum from the covariance matrix and the respective rays of each sample location; 
 determine a maximum calculated power from the minimum variance power spectrum to identify the location of blood flow in the region of interest. 
 
     
     
         8 . A Doppler ultrasound system, comprising:
 a probe having a multi-element transducer including a plurality of transducer elements;   a transmitter circuit operably coupled to the transducer elements of the transducer and configured to generate respective drive signals for driving the transducer elements to deliver an ultrasound beam;   a receiver circuit operably coupled to the transducer elements of the transducer and configured to receive echo signals detected by the respective transducer elements and generate in response thereto echo data representing the echo signals; and   a processor operably coupled to the transmitter and receiver circuits and configured to control the transmit circuit in generating drive signals for the transducer elements and configured to process the echo data from the receiver circuit and extract therefrom Doppler shift signals represented by Doppler shift data, the processor further configured to process the Doppler shift data to locate blood flow in a region of interest and automatically calculate data for identifying the location of the blood flow in the region of interest.   
     
     
         9 . The Doppler ultrasound system of  claim 8  wherein the processor is further configured to calculate data for displaying the location of the blood flow in a lateral display. 
     
     
         10 . The Doppler ultrasound system of  claim 8  wherein the processor is configured to control the transmitter circuit to scan the ultrasound beam over the region of interest over a compound-mode virtual surface. 
     
     
         11 . The Doppler ultrasound system of  claim 8  wherein the processor is configured to control the transmitter circuit to scan the ultrasound beam over the region of interest and automatically calculate data for identifying the location of the blood flow in the region of interest from the echo data. 
     
     
         12 . The Doppler ultrasound system of  claim 8  wherein the processor is configured to control the transmitter circuit to deliver the ultrasound beam to a plurality of sample location over the region of interest, wherein the region of interest has a lateral extent in two-dimensions relative to the probe and there are at least two different planes that are defined which have two or more beam axes lying in the respective plane. 
     
     
         13 . The Doppler ultrasound system of  claim 8  wherein the receiver circuit comprises a plurality of receive circuits, each receive circuit operably coupled to a respective one of the transducer elements and configured to receive the echo signals detected by the respective transducer element and generate in response thereto echo data representing the respective echo signal. 
     
     
         14 . The Doppler ultrasound system of  claim 13  wherein each receive circuit comprises:
 an amplifier configured to bandpass filter and amplify the respective echo signal in generating an output signal; and 
 an analog-to-digital converter circuit coupled to the amplifier and configured to digitize the output signal from the amplifier and generate digital echo data representing the output signal.