Steady state perfusion methods
Methods for assessing ischemic coronary artery disease are provided. The methods include administering a contrast agent that binds to a serum protein component to an animal and obtaining an MR image of the animal's myocardium during a period when the animal is experiencing hyperemia.
1 . An MR method of assessing the presence or absence of ischemic coronary artery disease comprising:
a) administering intravenously to an animal a MR contrast agent which noncovalently binds to a serum protein component; and
b) obtaining at least one MRI scan of said animal's myocardium during a period when said animal is experiencing a hyperemic response, provided that said at least one hyperemic MRI scan occurs at a time period when said contrast agent is in steady-state equilibrium in the blood of said animal.
2 . The method of claim 1 , wherein said at least one hyperemic MRI scan is obtained at least 3 minutes after said intravenous administration of said contrast agent.
3 . The method of claim 1 , further comprising obtaining at least one MRI scan of said animal's myocardium during a period of rest of said animal, provided that said at least one rest MRI scan occurs at a time period when said contrast agent is in steady-state equilibrium in the blood of said animal.
4 . The method of claim 1 , wherein said serum protein component is HSA.
5 . The method of claim 1 , wherein said contrast agent is MS-325.
6 . The method of claim 1 , wherein about 0.01 to about 0.2 mmol/kg of said contrast agent is injected.
7 . The method of claim 1 , wherein said hyperemic response is obtained by administering a pharmacologic stress agent to said animal.
8 . The method of claim 7 , wherein said pharmacologic stress agent is an A 2A agonist.
9 . The method of claim 7 , wherein said pharmacologic stress agent is selected from adenosine, dipyridamole, and dobutamine.
10 . The method of claim 1 wherein the hyperemic response is produced by physical stress.
11 . The method of claim 10 , wherein said physical stress is the result of exercise utilizing a bicycle or a treadmill device.
12 . The method of claim 3 , further comprising comparing the at least one rest MRI scan to the at least one hyperemic MRI scan.
13 . The method of claim 1 , further comprising obtaining at least one MRI scan of a coronary artery of said animal at any time after step a).
14 . The method of claim 1 , further comprising determining the degree or severity of ischemic coronary artery disease.
15 . The method of claim 7 , wherein an antidote to the pharmacologic stress agent is administered to end the hyperemic response.
16 . The method of claim 15 , wherein at least one MRI rest scan of said animal's myocardium is obtained after said administration of said antidote, wherein a hyperemic response in said animal is re-attained upon administration of a second dose of a pharmacologic stress agent, and wherein at least one MRI scan of said animal's myocardium is obtained during said second period of hyperemic response.
17 . An MR method of assessing the presence or absence of ischemic coronary artery disease comprising:
a) administering intravenously to an animal a MR contrast agent which is not covalently bound to a serum protein component; and
b) obtaining at least one MRI scan of said animal's myocardium during a period when said animal is experiencing a hyperemic response, provided that said at least one hyperemic MRI scan occurs at a time period when said contrast agent is in steady-state equilibrium in the blood of said animal.