MR contrast agents: Physical and pharmacologic basics

Abstract

Since approval of the first magnetic resonance (MR) contrast agent was granted in 1988, there has been remarkable growth in the utilization of intravenous gadolinium (Gd)-based agents. Currently it is estimated that nearly half of all MR studies performed are contrast-enhanced. Despite containing a toxic heavy metal, these agents have proven to be not only an effective diagnostic adjunct to non-enhanced MRI, but also remarkably well tolerated and safe. As a result, conventional wisdom has been that MR contrast media are "biologically inert," a notion that is clearly false. Ultimately, it is the radiologist's responsibility to understand the potential adverse effects of Gd-based agents and the special situations in which they are likely to occur; however, the basic pharmacology of contrast agents is generally not included in medical school curricula or formally taught in residency. The purpose of this review is to discuss the mechanism of action of MR contrast agents and relevant aspects of their clinical pharmacology, including effects on the cardiovascular and renal systems, potential laboratory errors, and special situations involving women and children. We also briefly discuss the issue of nephrogenic systemic fibrosis (NSF).

Discrepancies between the fate of myoblast xenograft in mouse leg muscle and NMR label persistency after loading with Gd-DTPA or SPIOs

“…injection, low molecular weight Gd chelates are rapidly eliminated through glomerular filtration, with a blood half-life shorter than 30 min. 25,26 Similarly, lanthanide-based CAs, which are released in the interstitium in the case of labeled cell death, also ought to be rapidly cleared by the kidney. With this class of CA, label recapture by other cells can be expected to be less of a problem than with SPIOs.…”

Gadolinium-Based Contrast Agent Accumulation and Toxicity: An Update

“…2,3 These adverse reactions are more common in patients with history of asthma, allergies, and renal insufficiency and in patients injected at faster rates. 1,4,5 GBCAs had an exceptional safety reputation from 1988 to 2006, to the point that in 2004 and 2005 GBCAs were recommended as a substitute for iodine-based contrast media in patients with renal failure for CT and in interventional studies. [6][7][8][9] In 2006, the association between the administration of GBCAs and the development of nephrogenic systemic fibrosis (NSF) in patients with renal insufficiency was described.…”

Erratum to: Magnetic resonance imaging in patients with meningitis induced hearing loss

“…Furthermore, one might want to consider that the utilisation of gadolinium is not entirely without risk and Fig. 3 Observations of the radiologists extra caution is warranted in very young children (who form a big group amongst cochlear implant candidates) due to their renal immaturity [23].…”