Ultrasound system with iterative high pass filter selection

Abstract

Disclosed herein is the iterative selection of an optimal high pass filter for progressive, ordered filtering of clutter from ultrasound color flow imaging data wherein a criterion for selecting the optimal high pass filter is if a mean frequency of filtered signal data is less than a clutter frequency threshold wherein if the mean frequency is less than the clutter frequency threshold is determined by whether an absolute value of an imaginary part of a first order autocorrelation of the filtered signal data is less than a constant times a real part of the autocorrelation, where the constant is determined by the clutter frequency threshold, wherein a high pass filter input for each iterative selection is the original ultrasound color flow imaging data.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation and claims the priority benefit of U.S. patent application Ser. No. 10 / 825,719 for “Ultrasound Clutter Filtering with Iterative High Pass Filter Selection” filed Apr. 16, 2004 and now U.S. Pat. No. ______, which is a continuation and claims the priority benefit of U.S. patent application Ser. No. 10 / 167,606 for a “System and Method for Adaptive Clutter Filtering in Ultrasound Color Flow Imaging” filed Jun. 11, 2002 and now U.S. Pat. No. 6,733,455, Which is a continuation-in-part and claims the priority benefit of U.S. patent application Ser. No. 10 / 081,542 for a “User Interface for Handheld Imaging Devices” filed Feb. 20, 2002 and now abandoned, which is a continuation-in-part and claims the priority benefit of U.S. patent application Ser. No. 09 / 860,209 for a “Miniaturized Ultrasound Apparatus and Method” filed May 18, 2001 and now U.S. Pat. No. 6,569,102, which is a continuation and claims the priori...

AI Technical Summary

Problems solved by technology

In practice, there are two significant challenges in producing a real-time color flow image.

First, the echoes returning from moving blood are generally very weak, so typically a packet of several or more transmit and receive cycles are needed to detect flow along a particular scan line.

The second practical challenge stems from the fact that the tissue medium, and especially bones and tissue layers that comprise the vessel walls of the insonified blood vessel, often produce very strong reflections that are orders of magnitude larger than the backscattered signals from blood.

Without first removing the clutter, the I / Q data analysis would be dominated by clutter effects and will not reflect the desired flow signal properties.

If the filter cutoff is always set high to reject the highest possible clutter frequencies, then some low flow signals may not be detected well.

If the filter cutoff frequency is always set low, color flashes may result in the image whenever significant clutter power due to tissue motion is present above the cutoff frequency.

Images