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Late gadolinium enhancement (LGE) and T1 mapping allow infarction and fibrosis to be identified for characterizing cardiomyopathy and assessing viability. [8] Magnetic resonance angiography may be performed with or without contrast medium and is used to assess congenital or acquired abnormalities of the coronary arteries and great vessels. [9]
Cardiac magnetic resonance imaging perfusion (cardiac MRI perfusion, CMRI perfusion), also known as stress CMR perfusion, [1] is a clinical magnetic resonance imaging test performed on patients with known or suspected coronary artery disease to determine if there are perfusion defects in the myocardium of the left ventricle that are caused by narrowing of one or more of the coronary arteries.
As a free solubilized aqueous ion, gadolinium(III) is highly toxic, but the chelated compounds are generally regarded as safe for individuals without kidney disease. Free Gd 3+ has a median lethal dose of 0.34 mmol/kg (IV, mouse) [ 27 ] or 100–200 mg/kg, but the LD50 is increased by a factor of 31 times [ 28 ] when Gd 3+ is chelated.
Additional benefits from cardiac MRI include the ability to detect scar within the heart using late gadolinium enhancement, and identify other abnormalities of the heart muscle itself such as infiltration with iron or amyloid protein. [11] Disadvantages of MRI include lengthy protocols and the potential for claustrophobia.
Steady-state free precession (SSFP) imaging is a magnetic resonance imaging (MRI) sequence which uses steady states of magnetizations. In general, SSFP MRI sequences are based on a (low flip angle) gradient echo MRI sequence with a short repetition time which in its generic form has been described as the FLASH MRI technique. While spoiled ...
MRI without contrast agents is the imaging mode of choice for pre-surgical, in-utero diagnosis and evaluation of fetal tumors, primarily teratomas, facilitating open fetal surgery, other fetal interventions, and planning for procedures (such as the EXIT procedure) to safely deliver and treat babies whose defects would otherwise be fatal.
The contrast agents used for DCE-MRI are often gadolinium based. Interaction with the gadolinium (Gd) contrast agent (commonly a gadolinium ion chelate) causes the relaxation time of water protons to decrease, and therefore images acquired after gadolinium injection display higher signal in T1-weighted images indicating the present of the agent.
A contrast agent (or contrast medium) is a substance used to increase the contrast of structures or fluids within the body in medical imaging. [1] Contrast agents absorb or alter external electromagnetism or ultrasound, which is different from radiopharmaceuticals, which emit radiation themselves.