Ablavar

Whatever happened to Ablavar? 
Ablavar (gadofosveset)
Ablavar® (gadofosveset), the most recently approved gadolinium-based MR contrast in the US, was withdrawn as a product in 2017 by its manufacturer due to poor sales. Ablavar® had been designed specifically for vascular imaging.  As seen in the structural diagram right, Ablavar® is a derivative of Gd-DTPA with a diphenyl-cyclohexyl-phosphate group attached to the ligand. This moiety resulted in appreciable (80-90%) reversible bonding to plasma proteins (principally albumin) when injected into the blood, allowing it to be confined intravascularly for several hours. As only a relatively small amount reached the extracellular spaces, Ablavar® could not be used interchangeably with other nonspecific gadolinium-contrast agents (to detect blood-brain barrier breakdown, for example). Following IV injection, two sets of images were typically acquired -- a first-pass arterial phase and later steady-state phase showing distribution through the entire vascular system (arteries and veins). ​
Ablavar (gadofosveset)
Ablavar® "first pass" arterial phase
Ablavar (gadofosveset)
Ablavar® "steady state" phase
Because no purely intravascular gadolinium-based MR contrast agent is currently available, some centers are performing contrast-enhanced MRA with the "off-label" use of ferumoxytol, an iron colloid solution approved for treatment of anemia. 

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References
     Rapp JH, Wolff SD, Quinn SF, et al. Aortoiliac occlusive disease in patients with known or suspected peripheral vascular disease: safety and efficacy of gadofosveset-enhanced MR angiography—multicenter comparative phase III study. Radiology 2005; 236:71-78
Related Questions
     So many gadolinium contrast agents are now available. What are the differences among them?  
     I've heard about using the iron supplement Ferumoxytol as an MR contrast agent. What is it and how does it work?