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Coronary MR angiography

Coronary MR angiography is a promising technique for coronary artery imaging in 3D, as it is non-invasive, non-irradiating and does not necessarily require injecting a contrast agent.
However numerous technical difficulties need to be overcome, and no validated method or sequence exists to date.
Therefore we will focus on the constraints involved in coronary MR angiography techniques, and the solutions currently available.

Technical challenges

The coronary vascular system is small in caliber and sinuous, relatively spread out in space, with the presence of pericardial fat on contact. Coronary MR angiography thus has to establish a compromise between acquisition time, spatial resolution, ratio of contrast versus noise and the correction of cardiac and respiratory motion.

State of the art

	Speed	Cardiac motion	Respiratory motion	Spatial resolution	Contrast	Signal/Noise
High field						Incr.
Parallel acquisition	Incr.
Segmented / spiral k-space filling	Incr.
Real time imaging	Incr.	X	X	Decr.
Target study of coronary axis routes	Incr.
Global 3D study of the entire heart	Decr.			Incr.		Incr.
Cardiac synchro in mid-diastole	Decr.	X
Breath-hold			X
Echo navigator	Decr.		X
Gradient echo with balanced gradients	Incr.				Incr.
Contrast agents with vascular remanence					X
Dark blood imaging					X
T₂ pre-impulsion					Incr.
Fat Saturation					Incr.

Potential clinical applications

Coronary stenosis
Coronary bypass
Imaging of plaque and the artery walls

Summary

Optimizing cardiac MRI

Cardiac MRI sequences

Coronary MR angiography

Technical challenges

State of the art

Potential clinical applications