Apparatus for ultrasound flow vector imaging and methods thereof

• US 10,335,113 B2
• Filed: 02/28/2017
• Issued: 07/02/2019
• Est. Priority Date: 11/19/2013
• Status: Active Grant

• Current Assignee: Versitech Limited (Government of Hong Kong Special Administrative Region)
• Original Assignee: Versitech Limited (Government of Hong Kong Special Administrative Region)
• Inventors: Yu, Alfred Cheuk Hang, Yiu, Yat Shun
• Primary Examiner(s): Santos Rodriguez, Joseph M
• Application Number:
  US15/445,582
• Publication Number:
  US 20170215836A1
• Time in Patent Office: 854 Days
• CPC Class Codes: A61B 8/02 Measuring pulse or heart rate
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• CPC Class Codes: A61B 8/0891 for diagnosis of blood vessels
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61B 8/4494 characterised by the arrangement of the transducer elements devices for short-range imaging using particular transducer elements arrangements under G01S15/8909; arrangements of transducers in generation of mechanical vibrations of infrasonic, sonic or ultrasonic frequency B06B1/0607
• CPC Class Codes: A61B 8/461 Displaying means of special interest
• CPC Class Codes: A61B 8/469 for selection of a region of interest
• CPC Class Codes: A61B 8/488 involving Doppler signals
• CPC Class Codes: A61B 8/5207 involving processing of raw data to produce diagnostic data, e.g. for generating an image reconstruction G06T11/00
• CPC Class Codes: A61B 8/5215 involving processing of medical diagnostic data
• CPC Class Codes: A61B 8/5223 for extracting a diagnostic or physiological parameter from medical diagnostic data for algorithms to analyse biomedical images G06T7/0012
• CPC Class Codes: G01S 15/58 Velocity or trajectory determination systems; Sense-of-movement determination systems velocity measurement in imaging systems G01S15/8979
• CPC Class Codes: G01S 15/8915 using a transducer array
• CPC Class Codes: G01S 15/8984 Measuring the velocity vector
• CPC Class Codes: G01S 7/52073 Production of cursor lines, markers or indicia by electronic means
• CPC Class Codes: G01S 7/52085 Details related to the ultrasound signal acquisition, e.g. scan sequences control of medical diagnostic ultrasound devices A61B8/54
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

Apparatus and methods of use are provided for complex flow imaging and analysis that is non-invasive, accurate, and time-resolved. It is particularly useful in imaging of vascular flow with spatiotemporal fluctuations. This apparatus is an ultrasound-based framework called vector projectile imaging (VPI) that can dynamically render complex flow patterns over an imaging view at millisecond time resolution. The VPI apparatus and methods comprise: (i) high-frame-rate broad-view data acquisition (based on steered plane wave firings); (ii) flow vector estimation derived from multi-angle Doppler analysis (coupled with data regularization and least-squares fitting); and (iii) dynamic visualization of color-encoded vector projectiles (with flow speckles displayed as adjunct).

Claims

1. An ultrasound imaging system comprising:

a data acquisition unit, which transmits, via an ultrasonic array transducer, a series of plane waves into a tissue and receives waves reflected from the tissue to obtain beam-formed data frames;

a flow vector estimation unit which estimates flow vectors at pixels of the data frames using data of the data frames; and

a display rendering circuit which displays, on a display, the flow vectors estimated as color coded moving projectiles having varying lengths and colors themselves across the moving projectiles based on velocity magnitudes of one or more flow vectors of the flow vectors corresponding to the moving projectiles, wherein positions of the projectiles are dynamically updated between data frames based on axial lateral velocities of the projectiles representing the corresponding flow vectors across the data frames and one or more inter-frame periods between the data frames to depict movement of the projectiles corresponding to one or more flow patterns in the tissue.

2. The system of claim 1, wherein projectile length of the projectiles are set based on velocity magnitudes at the pixels.

3. The system of claim 1, wherein direction of the projectiles shows flow direction at the pixels.

4. The system of claim 1, wherein the display rendering circuit displaying the flow vectors estimated as moving projectiles comprises:

selecting a set of pixels in a data frame as projectile launch points;

displaying the flow vectors at the set of pixels selected as projectiles;

calculating incremental displacement of the next frame based on the corresponding axial-lateral velocities of the projectiles and the one or more inter-frame periods;

updating positions of projectiles in the next frame based on the displacement calculated; and

displaying projectiles of the next frame at the positions updated.

5. The system of claim 1, wherein a projectile is displayed only if a corresponding pixel position used to estimate one or more flow vectors for the projectile falls within a flow region.

6. The system of claim 1, wherein, when a corresponding pixel position used to estimate one or more flow vectors of a projectile does not fall within a flow region, a new projectile is regenerated at an original projectile launch point where the projectile was first created.

7. The system of claim 1, wherein the display rendering circuit further displays grayscale flow speckles together with the projectiles.

8. An ultrasound imaging method, comprising:

transmitting, via an ultrasonic array transducer, a series of plane waves into a tissue and receiving waves reflected from the tissue to obtain beam-formed data frames;

estimating flow vectors at pixels of the data frames using data of the data frames; and

displaying, on a display, the flow vectors estimated as color coded moving projectiles having varying lengths and colors themselves across the moving projectiles based on velocity magnitudes of one or more flow vectors of the flow vectors corresponding to the moving projectiles, wherein positions of the projectiles are dynamically updated between data frames based on axial lateral velocities of the projectiles representing the corresponding flow vectors across the data frames and one or more inter-frame periods between the data frames to depict movement of the projectiles corresponding to one or more flow patterns in the tissue.

9. The method of claim 8, wherein projectile length of the projectiles are set based on velocity magnitudes at the pixels.

10. The method of claim 8, wherein direction of the projectiles shows flow direction at the pixels.

11. The method of claim 8, wherein displaying the flow vectors estimated as moving projectiles comprises:

selecting a set of pixels in a data frame as projectile launch points;

displaying the flow vectors at the set of pixels selected as projectiles;

calculating incremental displacement of the next frame based on the corresponding axial-lateral velocities of the projectiles and the one or more inter-frame periods;

updating positions of projectiles in the next frame based on the displacement calculated; and

displaying projectiles of the next frame at the positions updated.

12. The method of claim 8, wherein a projectile is displayed only if a corresponding pixel position used to estimate one or more flow vectors of the projectile falls within a flow region.

13. The method of claim 8, wherein, when a corresponding pixel position used to estimate one or more flow vectors of a projectile does not fall within a flow region, a new projectile is regenerated at an original projectile launch point where the projectile was first created.

14. The method of claim 8, further comprising displaying grayscale flow speckles together with the projectiles.