The coronary arteries themselves currently cannot be visualized in routine MRI. There are essentially two ways of detecting myocardial ischemia perfusion disorders).
Perfusion reduction under Adenosine Stress
Similar to scintigraphy under Adenosine or Dipyridamole stress, the myocardium is exposed to a vasodilator (Adenosine). The difference between well and poorly perfused areas are thus enhanced. Compared to nuclear medicine, MRI can offer a significantly better spatial resolution, which for the first time allows subendocardial and transmural defects to be distinguished. We recommend this method to rule out significant CAD in patients with low pretest probability of CAD and to localize ischemia. Recent data shows that cardiac MRI is equivalent, if not superior, to SPECT in terms of diagnostic accuracy. In addition to perfusion deficits per se, fibrosis is also detectable utilizing the same examination. The examination itself lasts approximately 30-45 minutes, the stress itself lasts no longer than 2-3 minutes, making it well tolerable for the patient.
Patient preparation for an Adenosine stress-MRI
Wall motion disorders/contractile function disorders under Dobutamine Stress
Similar to the Dobutamine Stress Echo, the patient is stressed with Dobutamine up to a target heart rate according to standardized protocol. Wall movement is assessed in different image planes at rest and during each individual stress level. With good image quality in the echo, stress MRI and stress echo are comparable, with (more often in everyday life) limited image quality in the echo, MRI is far superior. All the advantages and disadvantages of a stress echo also apply to stress MRI. This method is very specific but less sensitive than other ischemia tests. We perform the Dobutamine stress MRI primarily when there are contraindications in performing an Adenosine stress MRI.