System for the noninvasive determination of tracer concentration in blood

• US 8,617,072 B2
• Filed: 05/20/2005
• Issued: 12/31/2013
• Est. Priority Date: 05/28/2004
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Peligrad, Dragos-Nicolae, Spies, Lothar, Paulus, Timo
• Primary Examiner(s): Matthews, Christine
• Assistant Examiner(s): Reddy, Sunita
• Application Number:
  US11/569,437
• Publication Number:
  US 20110060205A1
• Time in Patent Office: 3,147 Days
• Field of Search: 600/368, 600500-504, 600/407, 600/425, 600431-435, 600/420, 600/458, 702/25, 328/128, 328/133, 328/134
• US Class Current: 600/368
• CPC Class Codes: G16H 10/40 for data related to laboratory analysis, e.g. patient specimen analysis
• CPC Class Codes: G16H 30/40 for processing medical images, e.g. editing

Abstract

The invention relates to a general composite compartmental model and a compartmental analysis procedure to extract non-invasively the concentration (C_p) of the imaging agent in plasma (301), in metabolites (304, 504) and in blood elements (303) (like red cells, platelets, plasma protein etc.) from time signal curves measured within a reference tissue region (200). This is made possible by deploying an injection function (S_INJ(t)) as input which models the amount of imaging agent administered to the patient as a function of time. The invention allows the presentation of the plasma input function to the medical practitioner without the need for invasively drawing blood samples.

Claims

1. A method for evaluating image data that represent concentration of an imaging agent in a body volume, the method comprising:

determining an injection function (S_INJ(t)) that models an injection of the imaging agent into a reference region as a function of time;

determining a concentration of free imaging agent in plasma (C_P) in the reference region;

determining a time signal in the reference region via convolution and summing using the injection function, the concentration of the free imaging agent in plasma, impulse response functions of blood elements (G_B) and metabolites (G_MB) within a blood volume fraction (V_B) of a blood subsystem in the reference region, partial volume fractions of the blood elements (G_B) and the metabolites (G_MB), respectively, within the blood subsystem, impulse response functions of tissue (G_T) and metabolites (G_MT) within a tissue volume fraction (V_T) of a reference tissue subsystem in the reference region, and a partial volume fraction of the metabolites (G_MT) within the reference tissue subsystem, determining the time signal being executed by a processor; and

estimating a distribution of the imaging agent in blood of a patient using the time signal,

wherein the injection function is expressed as a volume flow of the imaging agent through one of a syringe and an infusion system into a vein of the patient.

2. The method of claim 1, further comprising:

evaluating a compartment model of the reference region, the reference region comprising the blood subsystem and the reference tissue subsystem.

3. The method of claim 2, wherein the compartment model comprises compartments for metabolites of the imaging agent in the blood subsystem and the reference tissue subsystem.

4. The method of claim 2, wherein the compartment model comprises compartments for binding of the imaging agent in the blood subsystem and the reference tissue subsystem with binding sites.

5. The method of claim 2, wherein evaluating the compartment model comprises evaluating a target region, in which the imaging agent is specifically bound, based on information obtained from the reference region.

6. The method of claim 2, wherein evaluating the compartment model comprises calculating errors associated with the evaluation of the image data based on different compartment models.

7. The method of claim 2, wherein evaluating the compartment model comprises displaying evaluation results.

8. An examination apparatus, comprising

an imaging system configured to generate image data of the body volume;

and

a data processing system configured to perform the method according to claim 1.

9. The examination apparatus of claim 8, wherein the imaging system comprises one of a PET, SPECT, CT, MR or US system.

10. The method of claim 1, wherein the tissue volume fraction comprises interstitial and intracellular volume fractions.

11. A non-transitory computer readable medium that stores programming code, executable by a computer, for evaluating image data that represent concentration of at least one imaging agent in a body volume, the computer readable medium comprising:

injection determining code for determining an (S_INJ(t)) injection function that models an injection of the imaging agent into a reference region as a function of time;

free imaging agent concentration determining code for determining a concentration of free imaging agent in plasma (C_P) in the reference region;

time signal determining code for determining a time signal in the reference region via convolution and summing using the injection function, the concentration of the free imaging agent in plasma, impulse response functions of blood elements (G_B) and metabolites (G_MB) within a blood volume fraction (V_B) of a blood subsystem in the reference region, partial volume fractions of the blood elements (G_B) and the metabolites (G_MB), respectively, within the blood subsystem, impulse response functions of tissue (G_T) and metabolites (G_MT) within a tissue volume fraction (V_B) of a reference tissue subsystem in the reference region, and a partial volume fraction of the metabolites (G_MT) within the reference tissue subsystem; and

estimating code for estimating a distribution of the imaging agent in blood of a patient using the time signal,

wherein the injection function is expressed as a volume flow of the imaging agent through one of a syringe and an infusion system into a vein of the patient.

12. The non-transitory computer readable medium of claim 11, further comprising:

evaluating code for evaluating a compartment model of the reference region, the reference region comprising the blood subsystem and the reference tissue subsystem.

13. The non-transitory computer readable medium of claim 12, wherein the compartment model comprises compartments for metabolites of the imaging agent in the blood subsystem and the reference tissue subsystem.

14. The non-transitory computer readable medium of claim 12, wherein the compartment model comprises compartments for binding of the imaging agent in the blood subsystem and the reference tissue subsystem with binding sites.

15. The non-transitory computer readable medium of claim 12, wherein the evaluating code comprises target region code for evaluating a target region, in which the imaging agent is specifically bound, based on information obtained from the reference region.

16. The non-transitory computer readable medium of claim 12, wherein the evaluating code comprises error code for calculating errors associated with the evaluation of the image data based on different compartment models.

17. The non-transitory computer readable medium of claim 12, further comprising display code for displaying evaluation results.

18. The non-transitory computer readable medium of claim 11, wherein the tissue volume fraction comprises interstitial and intracellular volume fractions.