Method and System for Non-Invasive Functional Assessment of Coronary Artery Stenosis

• US 20130246034A1
• Filed: 03/11/2013
• Published: 09/19/2013
• Est. Priority Date: 03/13/2012
• Status: Active Grant

• Current Assignee: Siemens Healthcare GMBH (Siemens AG)
• Original Assignee: Siemens AG, Siemens Corp. (Siemens AG)
• Inventors: Sharma, Puneet, Itu, Lucian Mihai, Kamen, Ali, Georgescu, Bogdan, Zheng, Xudong, Tek, Huseyin, Comaniciu, Dorin, Vega-Higuera, Fernando, Scheuering, Michael, Bernhardt, Dominik
• Granted Patent: US 10,373,700 B2
• Time in Patent Office: Days
• US Class Current: 703/11
• CPC Class Codes: A61B 2576/023 for the heart
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/1128 using image analysis A61B5/1127 takes precedence
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/503 for diagnosis of the heart
• CPC Class Codes: A61B 6/5217 extracting a diagnostic or physiological parameter from medical diagnostic data
• CPC Class Codes: G16B 5/00 ICT specially adapted for modelling or simulations in systems biology, e.g. gene-regulatory networks, protein interaction networks or metabolic networks
• CPC Class Codes: G16H 50/50 for simulation or modelling of medical disorders

Abstract

A method and system for non-invasive assessment of coronary artery stenosis is disclosed. Patient-specific anatomical measurements of the coronary arteries are extracted from medical image data of a patient acquired during rest state. Patient-specific rest state boundary conditions of a model of coronary circulation representing the coronary arteries are calculated based on the patient-specific anatomical measurements and non-invasive clinical measurements of the patient at rest. Patient-specific rest state boundary conditions of the model of coronary circulation representing the coronary arteries are calculated based on the patient-specific anatomical measurements and non-invasive clinical measurements of the patient at rest. Hyperemic blood flow and pressure across at least one stenosis region of the coronary arteries are simulated using the model of coronary circulation and the patient-specific hyperemic boundary conditions. Fractional flow reserve (FFR) is calculated for the at least one stenosis region based on the simulated hyperemic blood flow and pressure.

Claims

1. A method for non-invasive assessment of coronary artery stenosis, comprising:

extracting patient-specific anatomical measurements of the coronary arteries from medical image data of a patient acquired during rest state;

calculating patient-specific rest state boundary conditions of a model of coronary circulation representing the coronary arteries based on the patient-specific anatomical measurements and non-invasive clinical measurements of the patient at rest;

calculating patient-specific hyperemic boundary conditions of the model of coronary circulation based on the rest boundary conditions and a model for simulated hyperemia;

simulating hyperemic blood flow and pressure across at least one stenosis region of at least one coronary artery using the model of coronary circulation and the patient-specific hyperemic boundary conditions; and

calculating fractional flow reserve (FFR) of the at least one stenosis region based on the simulated hyperemic blood flow and pressure.

2. The method of claim 1, wherein the coronary circulation model comprises one-dimensional computational models representing the coronary arteries and aorta of the patient;

3. The method of claim 2, wherein the coronary circulation model further comprises a reduced order semi-empirical stenosis model representing the at least one stenosis region, coupled to the one-dimensional computational model representing the at least one coronary artery.

4. The method of claim 3, wherein the semi-empirical stenosis model calculates a pressure drop across the at least one stenosis region as a sum of a viscous term, a turbulent term, and an inertance term.

5. The method of claim 2, wherein the coronary circulation model further comprises a full-order three-dimensional computational model of the at least one stenosis region, coupled to the one-dimensional computational model representing the at least one coronary artery.

6. The method of claim 2, wherein the coronary circulation model further comprises lumped models representing coronary microvascular beds, each coupled to a termination of a one-dimensional computational model representing coronary artery branch.

7. The method of claim 1, wherein calculating patient-specific rest state boundary conditions of a model of coronary circulation representing the coronary arteries based on the patient-specific anatomical measurements and non-invasive clinical measurements of the patient at rest comprises:

calculating a resting microvascular resistance at the termination of each of the plurality of branches based on the patient-specific anatomical measurements and the non-invasive clinical measurements of the patient at rest.

8. The method of claim 7, wherein calculating patient-specific hyperemic boundary conditions of the model of coronary circulation based on the rest boundary conditions and a model for simulated hyperemia comprises:

calculating the hyperemic microvascular resistance at the termination of each of the plurality of branches based on the calculated resting microvascular resistance.

9. The method of claim 8, wherein calculating a resting microvascular resistance at the termination of each of the plurality of branches based on the patient-specific anatomical measurements and the non-invasive clinical measurements of the patient at rest comprises:

calculating a mean arterial pressure (MAP) based on a heart rate, a systolic blood pressure, and a diastolic blood pressure of the patient;

calculating a resting myocardial perfusion based on the heart rate and the systolic blood pressure of the patient;

calculating a total resting coronary flow based on the resting myocardial perfusion and a mass of the left ventricle of the patient; and

calculating the resting microvascular resistance at the termination of each of the plurality of branches based on the MAP and the total resting coronary flow.

10. The method of claim 9, wherein the mass of the left ventricle is estimated from the medical image data of the patient.

11. The method of claim 8, wherein calculating the hyperemic microvascular resistance at the termination of each of the plurality of branches based on the calculated resting microvascular resistance comprises:

determining a patient-specific total coronary resistance index (TCRI) based on the non-invasive clinical measurements of the patient; and

calculating the hyperemic microvascular resistance at the termination of each of the plurality of branches based on the calculated hyperemic microvascular resistance and the patient-specific TCRI.

12. The method of claim 11, wherein determining a patient-specific total coronary resistance index (TCRI) based on the non-invasive clinical measurements of the patient comprises:

calculating a resting average peak velocity based on a heart rate and a systolic blood pressure of the patient;

calculating a CFVR value for each branch of the coronary arteries based on an age of the patient; and

calculating the TCRI for each branch based on the CFVR value and an estimated resting mean arterial pressure (MAP).

13. The method of claim 11, wherein determining a patient-specific total coronary resistance index (TCRI) based on the non-invasive clinical measurements of the patient comprises:

calculating the TCRI based on a heart rate of the patient.

14. The method of claim 1, wherein calculating fractional flow reserve (FFR) of the at least one stenosis region based on the simulated hyperemic blood flow and pressure comprises:

calculating the FFR of the at least one stenosis region as a ratio of a mean simulated hyperemic pressure distal to the at least one stenosis and a mean simulated hyperemic aortic pressure over a cardiac cycle.

15. An apparatus for non-invasive assessment of coronary artery stenosis, comprising:

means for extracting patient-specific anatomical measurements of the coronary arteries from medical image data of a patient acquired during rest state;

means for calculating patient-specific rest state boundary conditions of a model of coronary circulation representing the coronary arteries based on the patient-specific anatomical measurements and non-invasive clinical measurements of the patient at rest;

means for calculating patient-specific hyperemic boundary conditions of the model of coronary circulation based on the rest boundary conditions and a model for simulated hyperemia;

means for simulating hyperemic blood flow and pressure across at least one stenosis region of at least one coronary artery using the model of coronary circulation and the patient-specific hyperemic boundary conditions; and

means for calculating fractional flow reserve (FFR) of the at least one stenosis region based on the simulated hyperemic blood flow and pressure.

16. The apparatus of claim 15, wherein the coronary circulation model comprises one-dimensional computational models representing the coronary arteries and aorta of the patient;

17. The apparatus of claim 15, wherein the means for calculating patient-specific rest state boundary conditions of a model of coronary circulation representing the coronary arteries based on the patient-specific anatomical measurements and non-invasive clinical measurements of the patient at rest comprises:

means for calculating a resting microvascular resistance at the termination of each of the plurality of branches based on the patient-specific anatomical measurements and the non-invasive clinical measurements of the patient at rest.

18. The apparatus of claim 17, wherein the means for calculating patient-specific hyperemic boundary conditions of the model of coronary circulation based on the rest boundary conditions and a model for simulated hyperemia comprises:

means for calculating the hyperemic microvascular resistance at the termination of each of the plurality of branches based on the calculated resting microvascular resistance.

19. The apparatus of claim 18, wherein the means for calculating a resting microvascular resistance at the termination of each of the plurality of branches based on the patient-specific anatomical measurements and the non-invasive clinical measurements of the patient at rest comprises:

means for calculating a mean arterial pressure (MAP) based on a heart rate, a systolic blood pressure, and a diastolic blood pressure of the patient;

means for calculating a resting myocardial perfusion based on the heart rate and the systolic blood pressure of the patient;

means for calculating a total resting coronary flow based on the resting myocardial perfusion and a mass of the left ventricle of the patient; and

means for calculating the resting microvascular resistance at the termination of each of the plurality of branches based on the MAP and the total resting coronary flow.

20. The apparatus of claim 18, wherein the means for calculating the hyperemic microvascular resistance at the termination of each of the plurality of branches based on the calculated resting microvascular resistance comprises:

means for determining a patient-specific total coronary resistance index (TCRI) based on the non-invasive clinical measurements of the patient; and

means for calculating the hyperemic microvascular resistance at the termination of each of the plurality of branches based on the calculated hyperemic microvascular resistance and the patient-specific TCRI.

21. A non-transitory computer readable medium storing computer program instructions for non-invasive assessment of coronary artery stenosis, the computer program instructions when executed by a processor cause the processor to perform operations comprising:

extracting patient-specific anatomical measurements of the coronary arteries from medical image data of a patient acquired during rest state;

calculating patient-specific rest state boundary conditions of a model of coronary circulation representing the coronary arteries based on the patient-specific anatomical measurements and non-invasive clinical measurements of the patient at rest;

calculating patient-specific hyperemic boundary conditions of the model of coronary circulation based on the rest boundary conditions and a model for simulated hyperemia;

simulating hyperemic blood flow and pressure across at least one stenosis region of at least one coronary artery using the model of coronary circulation and the patient-specific hyperemic boundary conditions; and

calculating fractional flow reserve (FFR) of the at least one stenosis region based on the simulated hyperemic blood flow and pressure.

22. The non-transitory computer readable medium of claim 21, wherein the coronary circulation model comprises one-dimensional computational models representing the coronary arteries and aorta of the patient;

23. The non-transitory computer readable medium of claim 21, wherein calculating patient-specific rest state boundary conditions of a model of coronary circulation representing the coronary arteries based on the patient-specific anatomical measurements and non-invasive clinical measurements of the patient at rest comprises:

calculating a resting microvascular resistance at the termination of each of the plurality of branches based on the patient-specific anatomical measurements and the non-invasive clinical measurements of the patient at rest.

24. The non-transitory computer readable medium of claim 23, wherein calculating patient-specific hyperemic boundary conditions of the model of coronary circulation based on the rest boundary conditions and a model for simulated hyperemia comprises:

calculating the hyperemic microvascular resistance at the termination of each of the plurality of branches based on the calculated resting microvascular resistance.

25. The non-transitory computer readable medium of claim 24, wherein calculating a resting microvascular resistance at the termination of each of the plurality of branches based on the patient-specific anatomical measurements and the non-invasive clinical measurements of the patient at rest comprises:

calculating a mean arterial pressure (MAP) based on a heart rate, a systolic blood pressure, and a diastolic blood pressure of the patient;

calculating a resting myocardial perfusion based on the heart rate and the systolic blood pressure of the patient;

calculating a total resting coronary flow based on the resting myocardial perfusion and a mass of the left ventricle of the patient; and

calculating the resting microvascular resistance at the termination of each of the plurality of branches based on the MAP and the total resting coronary flow.

26. The non-transitory computer readable medium of claim 24, wherein calculating the hyperemic microvascular resistance at the termination of each of the plurality of branches based on the calculated resting microvascular resistance comprises:

determining a patient-specific total coronary resistance index (TCRI) based on the non-invasive clinical measurements of the patient; and

calculating the hyperemic microvascular resistance at the termination of each of the plurality of branches based on the calculated hyperemic microvascular resistance and the patient-specific TCRI.

27. The non-transitory computer readable medium of claim 26, wherein determining a patient-specific total coronary resistance index (TCRI) based on the non-invasive clinical measurements of the patient comprises:

calculating a resting average peak velocity based on a heart rate and a systolic blood pressure of the patient;

calculating a CFVR value for each branch of the coronary arteries based on an age of the patient; and

calculating the TCRI for each branch based on the CFVR value and an estimated resting mean arterial pressure (MAP).

28. The non-transitory computer readable medium of claim 26, wherein determining a patient-specific total coronary resistance index (TCRI) based on the non-invasive clinical measurements of the patient comprises:

calculating the TCRI based on a heart rate of the patient.

29. The non-transitory computer readable medium of claim 21, wherein calculating fractional flow reserve (FFR) of the at least one stenosis region based on the simulated hyperemic blood flow and pressure comprises:

calculating the FFR of the at least one stenosis region as a ratio of a mean simulated hyperemic pressure distal to the at least one stenosis and a mean simulated hyperemic aortic pressure over a cardiac cycle.

30. A method for non-invasive assessment of coronary artery stenosis, comprising:

extracting patient-specific anatomical measurements of the coronary arteries from medical image data of a patient acquired during hyperemia state;

calculating patient-specific hyperemic boundary conditions of a model of coronary circulation representing the coronary arteries based on the patient-specific anatomical measurements and non-invasive clinical measurements of the patient at hyperemia;

simulating hyperemic blood flow and pressure across at least one stenosis region of at least one coronary artery using the model of coronary circulation and the patient-specific hyperemic boundary conditions; and

calculating fractional flow reserve (FFR) of the at least one stenosis region based on the simulated hyperemic blood flow and pressure.