Cardiovascular MR imaging includes the complete anatomical display of the heart with CINE imaging of all phases of the heartbeat. Ultrafast techniques make breath hold three-dimensional coverage of the heart in different cardiac axes feasible. Cardiac MRI provides reliable anatomical and functional assessment of the heart and evaluation of myocardial viability and coronary artery disease by a noninvasive diagnostic imaging technique.
Cardiovascular MRI offers potential advantages over radioisotopic techniques because it provides superior spatial resolution, does not use ionizing radiation, has no imaging orientations constraints and contrast resolution better than echocardiography. It also offers direct visualization and characterization of atherosclerotic plaques and diseased vessel walls and surrounding tissues in cardiovascular research.
MRI perfusion approaches measure the alteration of regional myocardial magnetic properties after the intravenous injection of contrast agents and assess the extent of injury after a myocardial infarction and the presence of myocardial viability with a technique based on late enhancement. Extracellular MRI contrast agents, like Gd-DTPA, accumulate only in irreversibly damaged myocardium after a time period of at least 10 minutes.
This type of patients may also have an implanted cardiac stent, bypass or a cardiac pacemaker and special caution should be observed on the MRI safety and the contraindications. While a number of coronary stents have been tested and reported to be MRI compatible, coronary stents must be assessed on an individual basis, with the medical team weighing the risks and benefits of the MRI procedure.

Cardiac MRI overview:

Cardiovascular MRI has become one of the most effective noninvasive imaging techniques for almost all groups of heart and vascular disease.

A chelate is a heterocyclic chemical compound whose molecules consist of a metal ion attached by coordinate bonds to at least two nonmetal ions. The parent organic compound is known as a chelating agent - for example, DTPA (diethylenetriaminepentaacetic acid) used in contrast agents. Chelates are used in analytical chemistry, in agriculture as carriers of essential trace metals, in water softening, and to remove an excess of iron, which may build up to toxic levels in the body. Metalloproteins may influence the performance of enzymes or provide a mechanism for the storage of iron in the spleen and plasma of the human body.
Paramagnetic metal ions such as gadolinium improve the MRI signal, but the toxicity of these uncomplexed metal ions makes the use of a chelate to bind the metal ion essential. The chelated metal ion could be safely excreted.

DAB-Am64-(1B4M-Gd)64 is a new macromolecular MRI contrast agent for the diagnosis of liver micro-metastasis, consisting of a polypropylenimine diaminobutane (DAB) dendrimer conjugated with a bifunctional DTPA derivative complexing Gd(III).

Short name: Dy-DOTA-4AmCE, central moiety: Dy2+, contrast effect: T2*enhanced
Dy-DOTA-4AmCE, a macrocyclic complex is characterized by a very slow water exchange, a complex compared with several Dy-DTPA derivatives known for their efficacy as T2 contrast agents at high magnetic fields.

Short name: Gd-BOPTA, generic name: Gadobenate dimeglumine
A paramagnetic MRI contrast agent (small molecular weight Gd-chelate) with 0.5 and 0.25 molar concentration.
The albumin-mediated relaxation enhancement may result in advantages for Gd-BOPTA over Gd-DTPA and other gadolinium agents in poorly vascularized, small, or lesions with low enhancement and in tumors with high concentrations of albumin. The substance is excreted partly by the kidneys (75-90%), partly by the biliary system (10-25%). The uptake in the liver is about 5% in humans. It is bolus injectable.

See Contrast Agents and MultiHance®.