DEVICE AND METHOD FOR DETERMINING ACTUAL TISSUE LAYER BOUNDARIES OF A BODY

• US 20130289409A1
• Filed: 12/27/2011
• Published: 10/31/2013
• Est. Priority Date: 01/05/2011
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Jeanne, Vincent, Shan, Caifeng, Maeueler, Sebastian
• Granted Patent: US 9,579,079 B2
• Time in Patent Office: Days
• US Class Current: 600/449
• CPC Class Codes: A61B 5/4872 Body fat
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61B 8/0858 involving measuring tissue layers, e.g. skin, interfaces
• CPC Class Codes: A61B 8/4254 using sensors mounted on the probe
• CPC Class Codes: A61B 8/46 Ultrasonic, sonic or infrasonic diagnostic devices with special arrangements for interfacing with the operator or the patient
• CPC Class Codes: G06T 7/0012 Biomedical image inspection

Abstract

The present invention relates to a device (8) for determining tissue layer boundaries of a body (14), comprising a probe (10) for acquiring (S12) two or more ultrasound images (36) at adjacent positions of a surface (12) of the body (14), a converter (44) for converting (S14) said ultrasound images (36) separately to depth signals (46), wherein a depth signal (46) is obtained by summing intensities of one of said ultrasound images (36) along a line (66) of substantially constant depth in the body (14), a detector (48) for detecting (S16) a set of candidate tissue layer boundaries (50) for an ultrasound image (36) by thresholding the depth signal (46) obtained for said ultrasound image (36), a selection means (52) for selecting (S18) from a set of candidate tissue layer boundaries (50) a nearest candidate tissue layer boundary (54) that is nearest to the surface (12) of the body (14), and a processing means (56) for determining (S20) an actual tissue layer boundary (58) from the nearest candidate tissue layer boundaries (54) obtained for various ultrasound images (36).

Claims

1. Processor for determining actual tissue layer boundaries of a body, from two or more ultrasound images acquired at adjacent positions of a surface of the body comprising

a converter for converting said ultrasound images separately to depth signals, wherein a depth signal is obtained by summing intensities of one of said ultrasound images along a line of substantially constant depth in the body,

a detector for detecting a set of candidate tissue layer boundaries for an ultrasound image by thresholding the depth signal obtained for said ultrasound image,

a selection means for selecting from a set of candidate tissue layer boundaries a nearest candidate tissue layer boundary that is nearest to the surface of the body, and

a processing means for determining an actual tissue layer boundary from the nearest candidate tissue layer boundaries obtained for the two or more ultrasound images.

2. Processor according to claim 1, wherein the selection means is adapted to select the nearest candidate tissue layer boundary only from among those candidate tissue layer boundaries that have a tissue boundary width exceeding a minimum tissue boundary width.

3. Processer according to claim 1, wherein said tissue layer boundaries are depth values and said means for determining an actual tissue layer boundary is based on averaging said nearest candidate tissue layer boundaries selected for various ultrasound images.

4. Processor according to claim 1, wherein said tissue layer boundaries are depth values and said means for determining an actual tissue layer boundary determines the actual tissue layer boundary based on the relative frequency of different nearest candidate tissue layer boundaries chosen for various ultrasound images, particularly by using the nearest candidate tissue layer boundary that occurs most frequently.

5. Processor according to claim 1, wherein said detector detects a set of candidate tissue layer boundaries for an ultrasound image by thresholding a weighted sum of said depth signal and a derivative of said depth signal.

6. Device according to claim 1, wherein said probe is adapted for acquiring said two or more ultrasound images at subsequent time points, further comprising a visual tracking means for tracking tissue layer boundaries over images acquired at subsequent time points, wherein said visual tracking means is adapted to estimate a refined actual tissue layer boundary.

7. Device for estimating a person'"'"'s fat- and/or fat-free mass, comprising a device for determining tissue layer boundaries of a body according to claim 1 and a body fat estimator for estimating the total fat- and/or fat-free mass values based on several actual tissue layer boundaries (58) that were determined at different places of the body.

8. Device according to claim 7, wherein the body fat estimator estimates the total body fat and/or fat-free mass values using a formula that involves a weighted sum of predetermined constants, an age of the patient, a sum of actual tissue layer boundaries, a square of the sum of actual tissue layer boundaries, and/or a logarithm of the sum of actual tissue layer boundaries.

9. Device according to claim 7, further comprising a user interface for providing a user with instructions to place the probe at certain locations on the body.

10. Device according to claim 7, further comprising a means for detecting movement of the probe, in particular movement of the probe that is tangential to the surface of said body, for determining the relative positions of the acquired ultrasound images.

11. Device according to claim 10, further comprising a means for comparing properties of said detected movement with properties of an expected movement.

16. Device for determining actual tissue layer boundaries of a body, comprising

a probe for acquiring two or more ultrasound images at adjacent positions of a surface of the body and

a processor according to claim 1 for processing said two or more ultrasound images to determine an actual tissue layer boundary of the body.

12. Method for determining actual tissue layer boundaries of a body from two or more ultrasound images acquired at adjacent positions of a surface of the body, comprising the steps of

converting said ultrasound images separately to depth signals, wherein a depth signal is obtained by summing intensities of one of said ultrasound images along lines of substantially equal depth in the body,

detecting a set of candidate tissue layer boundaries for an ultrasound image by thresholding the depth signal obtained for said ultrasound image,

selecting from a set of candidate tissue layer boundaries a nearest candidate tissue layer boundary that is nearest to the surface of the body, and

determining an actual tissue layer boundary from the nearest candidate tissue layer boundaries obtained for various ultrasound images.

13. Method for estimating fat- and/or fat-free mass values, comprising the steps of

determining actual tissue layer boundaries according to the method of claim 12 at several positions of the body, and

estimating the total body fat value based on said several actual tissue layer boundaries.

14. Computer program comprising program code means for causing a computer to carry out the steps of the method as claimed in claim 12 when said computer program is carried out on the computer.

15. (canceled)