Method of and apparatus for predicting computed tomography contrast enhancement with feedback
First Claim
1. A method of determining a set of parameters for an injection protocol for scanning a tissue in a patient using computed tomography, the patient having a plurality of patient specific parameters, wherein the tissue to be scanned is enhanced with an intravascularly injected contrast agent, comprising the steps of:
- generating a tissue enhancement function comprising a tissue enhancement level for the tissue to be scanned as a function of an elapsed time after injection based on the patient specific parameters and a specified injection protocol; and
determining the set of injection protocol parameters for an optimum scan based on the predicted tissue enhancement function.
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Abstract
A method and apparatus are disclosed for predicting prior to injection an organ specific contrast enhancement in a patient for a preselected contrast injection protocol for pre-determining a computed tomography scan. The invention is preferably implemented in a computer program which creates a mathematical model of human cardiovascular physiology in a hypothetical patient with a specific body habitus subjected to the pre-selected contrast injection protocol. The predicted contrast enhancement is then displayed for operator approval and may be then used to control a CT scanner or contrast injector system, to perform the injection and scan with the pre-selected injection protocol and scan parameters. The mathematical model includes models of organs and vessels using differential equations to describe mass transport of contrast agent through the cardiovascular system. Also disclosed are a method and apparatus for predicting optimum injection protocol for contrast agent by analyzing the predicted enhancement levels and updating the injection protocol until acceptable enhancement levels are predicted as well as a method and apparatus for determining an optimum scan interval when enhancement levels are predicted to exceed a threshold level for a time period greater than the scan duration. Further disclosed is a method and apparatus for monitoring a region of interest in the patient different from the region to be scanned after injection to calibrate the mathematical model and more accurately predict enhancement levels in the tissue to be scanned and calculate the optimum scan parameters.
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Citations
38 Claims
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1. A method of determining a set of parameters for an injection protocol for scanning a tissue in a patient using computed tomography, the patient having a plurality of patient specific parameters, wherein the tissue to be scanned is enhanced with an intravascularly injected contrast agent, comprising the steps of:
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generating a tissue enhancement function comprising a tissue enhancement level for the tissue to be scanned as a function of an elapsed time after injection based on the patient specific parameters and a specified injection protocol; and determining the set of injection protocol parameters for an optimum scan based on the predicted tissue enhancement function. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A contrast injector system comprising:
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a contrast injector; a computer having a memory connected to said contrast injector for controlling its operation; and a computer program in said computer memory, said computer program having means for predicting a structure specific CT enhancement level in a patient having a specific patient habitus based on a specified injection protocol. - View Dependent Claims (18, 19, 20, 21)
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22. A computed tomography system for scanning a tissue in a patient, the patient having a plurality of patient specific parameters, wherein the tissue to be scanned is enhanced with an intravascularly injected contrast agent, the system comprising:
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a computed tomography machine; an injector system in communication with the computed tomography machine; a computer having a memory, the computer in communication with both the injector system and the computed tomography machine for coordinating their operation; and a computer program in the computer memory, the computer program having means for predicting prior to injecting the contrast agent a tissue enhancement level for the tissue based on the patient specific parameters and a selected injection protocol. - View Dependent Claims (23, 24, 25, 26)
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27. A computer being programmed for predicting a structure specific CT enhancement level in a patient for a given patient habitus and a specific contrast injection protocol comprising:
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a computer having a memory; a computer program in said memory, the program having means for accepting patient specific information and contrast specific information which affect physiological parameters of contrast enhancement and means for computing and outputting structure specific enhancement levels as a function of an elapsed time after injection. - View Dependent Claims (28, 29, 30)
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31. A method for determining an injection protocol for injecting a contrast agent into a patient for enhancing a tissue desired to be scanned with computed tomography, the method comprising the steps of:
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generating a plurality of predicted tissue enhancement functions based on different patient parameters; and selecting one of said predicted tissue enhancement functions as being close to expected based upon feedback from a low dose scan of a region of interest. - View Dependent Claims (32, 33, 34, 37)
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35. A method for determining an injection protocol for injecting a contrast agent into a patient for enhancing a tissue desired to be scanned with computed tomography, the method comprising the steps of:
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generating a predicted tissue enhancement function; selecting a threshold level; and adjusting the injection protocol until the tissue enhancement function remains greater than the threshold level for a time period at least equal to a desired scan duration. - View Dependent Claims (36, 38)
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Specification