Method to determine contrast media injection parameters to control signal intensity during magnetic resonance angiography
Injection systems and related methods including an injection device, an operator interface, and modules to determine operational parameters during an MRA imaging procedure. Such parameters may be used to optimize and/or maximize signal intensity during an MRA imaging procedure. The injection system may include a target in-bloodstream contrast agent concentration determination module that determines a target in-bloodstream contrast agent concentration at least partially based on contrast agent type and MRA imager parameters. The injection system may include a contrast agent injection rate determination module that determines a contrast agent injection rate at least partially based on the target in-bloodstream contrast agent concentration, an initial contrast agent concentration, and a cardiac output rate of a patient to be imaged. The injection system may include a diluent injection rate determination module that determines a diluent injection rate at least partially based on the contrast agent injection rate.
1. A method for injecting a contrast agent into a patient to be imaged, comprising:
receiving an indication of a first imaging parameter for a magnetic resonance angiography (MRA) imager to be used in an MRA imaging procedure;
receiving an indication of a cardiac output rate of the patient to be imaged;
receiving an indication of a type of contrast agent to be used in said MRA imaging procedure and an initial concentration of said contrast agent;
determining a target concentration for a contrast agent in the bloodstream of the patient to be imaged, at least in part based on said type of contrast agent and said first imaging parameter;
determining an injection rate for said contrast agent at least in part based on said target concentration, said initial concentration, and said cardiac output rate; and
injecting said contrast agent at said injection rate into the patient.
2. The method of claim 1 , wherein said determining of said target concentration further utilizes a second imaging parameter, wherein said first imaging parameter is a pulse repetition time for said MRA imager, and wherein said second imaging parameter is an imaging delay time for said MRA imager.
3. The method of claim 1 , wherein said determining of said target concentration uses a formula relating contrast agent concentration in said patient to signal intensity received by said MRA imager during said MRA imaging procedure to determine a first level of concentration of said contrast agent where the rate at which the signal intensity changes divided by the rate at which the contrast agent concentration changes equals zero.
4. The method of claim 3 , wherein said first level of concentration is used as said target concentration.
5. The method of claim 1 , wherein said determining said injection rate includes dividing said target concentration by said initial contrast agent concentration to determine a concentration ratio and calculating said injection rate by multiplying said cardiac output rate by said concentration ratio.
6. The method of claim 1 , further including determining a diluent injection rate at least partially based on said contrast agent injection rate.
7. The method of claim 6 , wherein said determining said diluent injection rate includes subtracting said contrast agent injection rate from a standard total injection rate to determine said diluent injection rate.
8. The method of claim 1 , wherein said first imaging parameter is one of a pulse repetition time for said MRA imager, an imaging delay time for said MRA imager, a signal intensity for said MRA imager, or a field strength for said MRA imager.
9. The method of claim 1 , wherein said MRA imaging procedure is a spin-echo imaging sequence.
10. The method of claim 1 , wherein said MRA imaging procedure is a gradient-echo imaging sequence.
11. The method of claim 1 , further including providing an operator interface that receives inputs from an operator.
12. The method of claim 11 , wherein said contrast agent type is received from said operator interface.
13. The method of claim 11 , wherein said initial concentration of said contrast agent is received from said operator interface.
14. The method of claim 11 , wherein said cardiac output rate is received from said operator interface.
15. The method of claim 11 , wherein said first imaging parameter is received from said operator interface.