Contrast-enhanced magnetic resonance angiography (CE-MRA) with standard extracellular contrast material is well established
for vascular imaging. Recently, the first blood pool contrast agent (BPA) has become clinically available. This paper reviews
characteristics and classification of BPA as well as first clinical experience in various vascular territories. BPAs comprise
gadolinium-based compounds, synthetic compounds, and ultrasmall superparamagnetic iron-oxide (USPIO) particles. Such BPAs
are retained in blood with a prolonged time-window of enhancement as compared to extracellular gadolinium chelates. Promising
results from USPIO at first-pass and steady-state angiography have been published, but no USPIO is approved yet. Gadofosveset
is the first clinically approved BPA. After bolus injection, gadofosveset binds noncovalently to serum-albumine, thus enhancing
relaxivity. First published results from carotid, coronary, renal, and peripheral angiography are encouraging; particularly
helpful is prolonged enhancement during steady state. More BPAs have been clinically evaluated, but no approval has been granted.
Bolus-injectable BPAs allow for first-pass CE-MRA similar to standard extracellular contrast media, but with higher relaxivity,
allowing lower doses and reduced injection rates. An additional feature of BPA is the steady-state phase with a broad time
window enabling high-resolution angiography or double-gated angiography of coronary arteries to compensate for the complex
motion pattern.
Keywords Magnetic resonance angiography - Blood pool contrast media - Gadolinium chelates - Ultrasmall iron oxide particles