cardiovascular disorders
Cardiac Imaging Tests
Magnetic Resonance Imaging (MRI) in Cardiac Diagnosis
 Magnetic Resonance Imaging None after injecting a paramagnetic contrast agent (gadolinium-diethylenetriamine pentaacetic acid [Gd-DTPA]) produces higher resolution of myocardial perfusion patterns than does radionuclide imaging. MRI is generally considered the most accurate and reliable measure of ventricular volumes as well as ejection fraction. However, patients with impaired renal function can develop Disadvantages of MRI , a potentially life-threatening disorder, after use of gadolinium contrast. Contrast agents are being developed that are safe to use in patients with impaired renal function. or by using a contrast agent (eg, Gd-DTPA, which is excluded from cells with intact membranes). MRI discriminates myocardial scar from inflammation with edema. In patients with Marfan Syndrome , MRI measurements of ascending aorta dilation are more accurate than echocardiographic measurements. MRI is increasingly being used in the evaluation of nonischemic cardiomyopathies such as Magnetic resonance angiography(MRA), after injection of a gadolinium contrast agent, is used to assess blood volumes of interest (eg, blood vessels in the chest or abdomen); all blood flow can be assessed simultaneously. MRA can be used to detect aneurysms, stenosis, or occlusions in the carotid, coronary, renal, or peripheral arteries. (MRV) can be used as an alternative to ultrasonography to detect Diagnosis ; however, MRV is less well studied and more expensive than ultrasonography. 