Cardiac MRI Stress Perfusion Imaging
Radiology Regional Center is proud to introduce an exciting new diagnostic procedure. Cardiac MRI Stress Perfusion Imaging is now available. This comprehensive exam can evaluate left ventricular function, morphology, viability and perfusion all within a 1 hour period.
When is Cardiac MRI Stress Perfusion indicated?
In 2006, a consensus panel from the American College of Cardiology Foundation noted the following indications as appropriate uses of stress perfusion MRI: evaluating chest pain syndromes in patients who have intermediate probability of coronary artery disease(CAD) and certaining the physiologic signicance of indeterminate coronary lesions . Cardiac MR perfusion imaging is a physiologic test for coronary ischemia, as is stress nuclear imaging. However, unlike nuclear stress imaging, Cardiac MRI Stress imaging provides signicant additional information. Much like echocardiography, Cardiac MR can assess cardiac function, including valvular heart disease. Stress MR as also evaluates myocardial viability similar to Cardiac PET imaging. This is important when coronary revascularization is being considered.
How is CMR Stress testing performed?
The initial cine imaging sequences evaluate left ventricular function. Cardiac MR is actually the gold standard for assessing LV function. This is followed by the stress exam. During this exam, intravenous adenosine (vasodilator) is infused for approximately 2.5 minutes. This infusion is shorter than the typical infusion for nuclear stress imaging, often resulting in fewer side e-ects from the medication. Simultaneously, intravenous contrast is administered and Cardiac MRI Perfusion imaging sequences acquire 4-5 slices of the heart each and every heartbeat. This is followed by a resting perfusion exam and then Delayed Enhancement(DE) imaging of the heart.
How Sensitive is CMR Stress Perfusion/Delayed Enhancement Imaging?
A recent study from Duke University showed CMR stress perfusion/ DE Imaging to have a sensitivity, specicity and accuracy of 89%, 87% and 88% respectively, for detection of coronary stenosis >70%. Why is CMR stress perfusion/DE imaging so sensitive? Unlike stress nuclear imaging, CMR stress testing acquires two dierent sets of images to evaluate for the presence of coronary artery disease. CMR perfusion images test for the presence of inducible ischemia and Delayed enhancement imaging looks for any evidence of acute or chronic myocardial infarction.Compared to nuclear SPECT imaging, DE Imaging has a 60-fold spatial resolution advantage. Nuclear SPECT imaging misses as many as 50% of subendocardial myocardial infarctions that are detected by CMR DE Imaging.
What is the Prognostic Value of CMR Stress Perfusion Imaging?
A recent study notes4 that the 3 year event free survival in a patient with a normal Cardiac MRI Stress Perfusion exam is 99.2%. This compares very favorably with nuclear stress prognostic data. The 3 year event free survival in a patient with an abnormal CMR Stress Perfusion study drops to 83.5%.
Who will interpret the exam?
Once completed, the will be interpreted by a specially trained Cardiac MRI radiologist. Phone consultations will be available as needed.