Basics of non-invasive angiography contrast-enhanced magnetic resonance angiography

Contrast-enhanced magnetic resonance angiography is a non-invasive imaging modality without catheterization or nephrotoxicity. This is accomplished by using paramagnetic contrast agents in combination with very rapid acquisition sequences. Paramagnetic contrast agent is injected intravenously and image data are collected during the first-pass of contrast agent through the vascular territory of interest. Due to the strong enhancement effect of paramagnetic contrast agents, a small dose injected as an intravenous bolus is sufficient to briefly enhance the entire arterial vascular tree. This allows imaging with a large field-of view that encompasses an extensive region of vascular anatomy. By using a dedicated 3D imaging sequence on scanners with high-performance gradient systems, high-resolution 3D volumes of image data can be acquired in a single breath-hold. This has vastly improved image quality of 3D contrast-enhanced MRA (CE-MRA) exams, particularly in the chest and abdomen. Subsequent postprocessing allows an angiographic display of image data in any desired obliquity. The following part gives an overview and the basic principles of the methods used for CE-MRA.