Coronary MR angiography

Coronary MR angiography (coronary MRA) is a developing approach to imaging the coronary arteries.

Advantages of coronary MRA include avoidance of the intravenous iodinated contrast and ionizing radiation used in coronary CT angiography and conventional angiography.

A disadvantage of coronary MRA has been a problem with low signal-to-noise ratio when trying to image a small vessel with free breathing sequences. Current techniques also typically involve long scan times since ECG-gated and respiratory-gated acquisition is necessary to avoid motion blurring.

Technique

• 1.5 T: coronary MRA typically relies on SSFP sequences (gadolinium contrast not necessary for this sequence).
• 3 T: coronary MRA typically relies on gradient echo (GRE) sequences with a double dose of IV contrast agent.
• fat-saturation techniques (such as STIR or SPIR) are necessary to suppress epicardial fat surrounding the coronary arteries
• a T2W magnetization preparation pulse suppresses myocardial signal and venous blood signal in the epicardial veins

Future directions

3 T GRE contrast-enhanced whole heart coronary MRA sensitivity (94%) and specificity (82%) approaches that of 64-slice coronary CTA, but data about its prognostic ability has not yet been developed.

Siehe auch:

• Cardiac CT