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Cardiac magnetic resonance imaging.
Also known as cardiac MRI, is a medical imaging technology for non-invasive assessment of the function and structure of the cardiovascular system.
CMRI sequences are adapted for cardiac imaging by using ECG gating and high temporal resolution protocols.
CMRI is complementary to other imaging techniques, such as echocardiography, cardiac CT, and nuclear medicine.
Applications include assessment of myocardial ischemia and viability, cardiomyopathies, myocarditis, iron overload, vascular diseases, and congenital heart disease.
Cardiac MRI in cases of clinically suspected myocarditis should be performed within 2 to 3 weeks after initial presentation and is useful for its diagnostic sensitivity and for assessment and follow up to monitor the evolution of the disease.
It is valuable for diagnosis and surgical approach in complex congenital heart disease.
It can detect and characterize myocardial ischemia due to disease affecting the epicardial vessels and microvasculature.
Cardiac MRI is the gold standard for noninvasive assessment of LV volumes and LVEF because if it’s high accuracy and reproducibility.
Gadolinium enhancement and T1 mapping allow infarction and fibrosis to be identified for characterizing cardiomyopathy and assessing myocyte viability.
Can be used to assess congenital or acquired abnormalities of the coronary arteries and great vessels.
It avoids ionizing radiation.
Gadolinium based contrast medium is frequently used in CMR and has been associated with nephrogenic systemic fibrosis.
Intra-cranial deposition of gadolinium has been demonstrated..
Imaging of the cardiovascular system is usually performed with cardiac gating using an adaptation of conventional ECG techniques.
T1-weighted sequences are used to visualize anatomy and detect the presence of intra-myocardial fat, and to quantify diffuse myocardial fibrosis.
T2-weighted imaging is primarily used to detect myocardial edema which may be seen in acute myocarditis or infarction.
Phase-contrast imaging is used to assess valve disease and quantify shunts.
Contrast medium is given intravenously to assess myocardial perfusion.
It can provide information about the nature of congenital hearts defects without using x-rays or being invasive.
In congenital heart disease it is typically used with other diagnostic techniques.
Use of CMRI: when echocardiography cannot provide sufficient diagnostic information, as an alternative to diagnostic cardiac catheterization which involve risks including x-ray radiation exposure, to obtain diagnostic information for which CMR offers unique advantages such as blood flow measurement or identification of cardiac masses, and when clinical assessment and other diagnostic tests are inconsistent.
Conditions in which CMRI is often used include: tetralogy of Fallot, transposition of the great arteries, coarctation of the aorta, single ventricle heart disease, abnormalities of the pulmonary veins, atrial septal defect, connective tissue diseases such as Marfan syndrome, vascular rings, abnormal origins of the coronary arteries, and cardiac tumors.