Perfusion Assessment Method and System Based on Bolus Administration

• US 20080228080A1
• Filed: 12/21/2005
• Published: 09/18/2008
• Est. Priority Date: 12/23/2004
• Status: Active Grant

• Current Assignee: Bracco Suisse SA
• Original Assignee: Bracco Suisse SA
• Inventors: Frinking, Peter, Rognin, Nicolas, Arditi, Marcel
• Granted Patent: US 8,496,591 B2
• Time in Patent Office: Days
• US Class Current: 600/458
• 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 8/481 involving the use of contrast agent, e.g. microbubbles introduced into the bloodstream analysis of echo signal exploiting properties of a contrast enhancer in devices for short-range imaging with acoustic waves G01S7/52039

Abstract

A perfusion assessment system is proposed. The system includes means for providing an echo-power signal indicative of a perfusion of a contrast agent in a body-part under analysis, the contrast agent being administered as a bolus and undergoing a significant destruction during a passage of the contrast agent in the body-part, means for associating the echo-power signal to a model function including the product between a bolus function indicative of the passage of the contrast agent without said destruction and a reperfusion function indicative of a reperfusion of the contrast agent in the body part following the destruction corresponding to a substantially constant inflow of the contrast agent, and means for estimating at least one perfusion indicator from the bolus function and/or the reperfusion function.

Claims

1. A perfusion assessment system including:

means for providing an echo-power signal indicative of a perfusion of a contrast agent in a body-part under analysis, the contrast agent being administered as a bolus and undergoing a significant destruction during a passage of the contrast agent in the body-part,

means for associating the echo-power signal to a model function including the product between a bolus function indicative of the passage of the contrast agent without said destruction and a reperfusion function indicative of a reperfusion of the contrast agent in the body part following the destruction corresponding to a substantially constant inflow of the contrast agent, and

means for estimating at least one perfusion indicator from the bolus function and/or the reperfusion function.

2. The system according to claim 1, wherein the reperfusion function has an S-shape, the S-shape including an initial portion with substantially zero first derivatives, a final portion with substantially zero first derivatives, and a central portion between the initial portion and the final portion changing monotonically from a value of the initial portion to a value of the final portion.

3. The system according to claim 2, wherein the means for providing the echo-power signal includes means for processing the echo-power signal to be proportional to a concentration of the contrast agent in the body-part.

4. The system according to claim 2, wherein the reperfusion function is a cumulative lognormal function being represented by a set of fitting parameters, and wherein the means for estimating includes means for deriving the at least one perfusion indicator from the fitting parameters, the at least one perfusion indicator being representative of haemodynamic characteristics of the body-part.

5. The system according to claim 2, wherein the reperfusion function is based on a plurality of elementary reperfusion functions with said S-shape each one for a corresponding value of at least one perfusion parameter, the elementary perfusion functions being weighted according to a probability density distribution of the at least one perfusion parameter, and wherein the means for estimating includes means for calculating at least one shape indicator of the probability density distribution, the at least one shape indicator being representative of morphological characteristics of the body-part.

6. The system according to claim 5, wherein each elementary reperfusion function is a cumulative normal distribution function based on a first predetermined parameter indicative of an echo-power signal measure sensitivity and a second predetermined parameter indicative of a contrast agent destruction extent.

7. The system according to claim 5, wherein the probability density distribution is a lognormal function of the at least one perfusion parameter and the reperfusion function includes the integral of the elementary reperfusion functions multiplied by the lognormal function, the lognormal function being represented by a set of fitting parameters, and wherein the means for calculating includes means for deriving the at least one shape indicator from the fitting parameters.

8. The system according to claim 5, wherein the probability density distribution is represented by a vector of probabilities, the reperfusion function including the summation of the elementary reperfusion functions multiplied by the corresponding probabilities, and wherein the means for calculating includes means for extracting the at least one shape indicator from the vector of probabilities.

9. The system according to claim 1, wherein the bolus function includes the sum of a plurality of elementary bolus functions.

10. The system according to claim 1, wherein the bolus function and each elementary bolus function is a lognormal function.

11. A diagnostic imaging equipment including ultrasound means for acquiring the echo-power signal and the perfusion assessment system according to claim 1.

12. The diagnostic imaging equipment according to claim 11, further including means for detecting the reaching of a maximum of the echo-power signal and means triggering the destruction in response to the detection of the reaching of the maximum.

16. The system according to claim 3, wherein the reperfusion function is a cumulative lognormal function being represented by a set of fitting parameters, and wherein the means for estimating includes means for deriving the at least one perfusion indicator from the fitting parameters, the at least one perfusion indicator being representative of haemodynamic characteristics of the body-part.

17. The system according to claim 3, wherein the reperfusion function is based on a plurality of elementary reperfusion functions with said S-shape each one for a corresponding value of at least one perfusion parameter, the elementary perfusion functions being weighted according to a probability density distribution of the at least one perfusion parameter, and wherein the means for estimating includes means for calculating at least one shape indicator of the probability density distribution, the at least one shape indicator being representative of morphological characteristics of the body-part.

18. The system according to claim 6, wherein the probability density distribution is a lognormal function of the at least one perfusion parameter and the reperfusion function includes the integral of the elementary reperfusion functions multiplied by the lognormal function, the lognormal function being represented by a set of fitting parameters, and wherein the means for calculating includes means for deriving the at least one shape indicator from the fitting parameters.

19. The system according to claim 6, wherein the probability density distribution is represented by a vector of probabilities, the reperfusion function including the summation of the elementary reperfusion functions multiplied by the corresponding probabilities, and wherein the means for calculating includes means for extracting the at least one shape indicator from the vector of probabilities.

20. The system according to claim 2, wherein the bolus function includes the sum of a plurality of elementary bolus functions.

13. A perfusion assessment method including the steps of:

providing an echo-power signal indicative of a perfusion of a contrast agent in a body-part under analysis, the contrast agent being administered as a bolus and undergoing a significant destruction during a passage of the contrast agent in the body-part,

associating the echo-power signal to a model function including the product between a bolus function indicative of the passage of the contrast agent without said destruction and a reperfusion function indicative of a reperfusion of the contrast agent in the body part following the destruction corresponding to a substantially constant inflow of the contrast agent, and

estimating at least one perfusion indicator from the bolus function and/or the reperfusion function.

14. A computer program directly loadable into a working memory of a data processing system for performing the method of claim 13 when the program is run on the system.

15. A program product including a computer readable medium embodying the program of claim 14.