System for delivery of gaseous imaging contrast agents and methods for using same

1. A system for delivery of a gaseous contrast agent to the lungs of a subject, the system comprising:

a first gas container defining an interior volume configured to contain said gaseous contrast agent, said first gas container having an outlet in fluid communication with said interior volume;

a second gas container defining an interior volume configured to contain oxygen gas, said second gas container having an outlet in fluid communication with said interior volume;

a flow meter having an inlet and an outlet, said inlet of said flow meter being in fluid communication with said outlets of said first and second gas containers such that said flow meter receives a mixture of said gaseous contrast agent and said oxygen gas, said flow meter being configured to produce a first flow signal indicative of the flow rate of said gaseous contrast agent within the flow meter and a second flow signal indicative of the flow rate of said oxygen gas within the flow meter;

a delivery tube defining a central bore and having a first end and an opposed second end, said second end of said delivery tube being configured for coupling to the mouth of said subject;

a first flow control valve positioned between said outlet of said flow meter and said first end of said delivery tube, said flow control valve being positioned in fluid communication with said outlet of said flow meter and said first end of said delivery tube, said flow control valve being configured to provide selective fluid communication between said outlet of said flow meter and said first end of said delivery tube;

a first pressure valve positioned between said outlet of said first gas chamber and said inlet of said flow meter, said first pressure valve being positioned in fluid communication with said outlet of said first gas container and said inlet of said flow meter, said first pressure valve being configured to provide selective fluid communication between said outlet of said first gas container and said inlet of said flow meter;

a second pressure valve positioned between said outlet of said second gas container and said inlet of said flow meter, said second pressure valve being positioned in fluid communication with said outlet of said second gas container and said inlet of said flow meter, said second pressure valve being configured to provide selective fluid communication between said outlet of said second gas container and said inlet of said flow meter,

an imaging device; and

a processor, said processor being positioned in operative communication with said flow meter, said flow control valve, said first and second pressure valves, and said imaging device, wherein said processor is configured to receive said first and second flow signals, wherein said processor is configured to selectively open said flow control valve in response to said first and second flow signals, and wherein said processor is configured to selectively activate said imaging device in response to said first and second flow signals.

2. The system of claim 1 , wherein said processor is configured to determine a monitored flow ratio corresponding to the ratio between the oxygen gas and the gaseous contrast agent within the flow meter, and wherein the processor is configured to compare the monitored flow ratio to a desired flow ratio.

3. The system of claim 1 , wherein said processor is configured to selectively open said first pressure valve such that a selected volume of said gaseous contrast agent enters said inlet of said flow meter, and wherein said processor is configured to selectively open said second pressure valve such that a selected volume of said oxygen gas enters said inlet of said flow meter.

4. The system of claim 3 , wherein said subject has a respiratory cycle, wherein said processor is configured to open said first pressure valve, said second pressure valve, and said flow control valve such that delivery of said mixture of said gaseous contrast agent and said oxygen gas to said delivery tube is synchronized with a selected point in the respiratory cycle of said subject.

5. The system of claim 4 , wherein said processor is configured to synchronize activation of said imaging device with the selected point in the respiratory cycle of said subject.

6. The system of claim 3 , wherein the total volume of said selected volumes of said gaseous contrast agent and said oxygen gas substantially corresponds to a tidal volume of the lungs of the subject.

7. The system of claim 1 , wherein said flow meter comprises a pneumotachometer.

8. The system of claim 1 , wherein said imaging device comprises a magnetic resonance imaging (MRI) machine.

9. The system of claim 1 , further comprising an interface element coupled to said second end of said delivery tube and configured for operative coupling to the mouth of the subject.

10. The system of claim 9 , wherein said interface element comprises a facemask.

11. The system of claim 9 , wherein said interface element comprises a mouthpiece.

12. The system of claim 1 , further comprising a collection container defining an interior space and having an inlet in fluid communication with said first end of said delivery tube, said collection container being configured to receive expired gases from said subject.

13. The system of claim 12 , further comprising a second flow control valve positioned between said first end of said delivery tube and said inlet of said collection container, said second flow control valve being positioned in fluid communication with said first end of said delivery tube and said inlet of said collection container, said flow control valve being configured to provide selective fluid communication between said delivery tube and said inlet of said collection container.

14. The system of claim 13 , wherein said processor is in operative communication with said second flow control valve, wherein said processor is configured to selectively open said second flow control valve, and wherein said processor is configured to synchronize opening of said second flow control valve with expiration by said subject.

15. The system of claim 1 , wherein said first gas container comprises a first reservoir bag, said first reservoir bag defining said outlet and said interior volume of said first gas container, and wherein said second gas container comprises a second reservoir bag, said second reservoir bag defining said outlet and said interior volume of said second gas container.

16. The system of claim 15 , wherein said first gas container further comprises a first chamber, wherein said second gas container further comprises a second chamber, said first chamber being configured to receive at least a portion of said first reservoir bag, said second chamber being configured to receive at least a portion of said second reservoir bag, said first and second chambers defining respective openings, wherein at least a portion of said outlet of said first reservoir bag is received within said opening of said first chamber, and wherein at least a portion of said outlet of said second reservoir bag is received within said opening of said second chamber.

17. The system of claim 16 , wherein the first and second chambers are configured to receive an inert gas, and wherein the processor is configured to selectively adjust the pressure within each respective chamber.