European researchers have developed derivatives of gadolinium complexes that are promising candidates for contrast agents in magnetic resonance imaging (MRI).

In MRI scans, contrast agents enhance the differences between signals from various tissues, resulting in clearer images. The latest clinical MRI instruments work in the field range of 3 Tesla and David Parker at the University of Durham, UK and colleagues are designing new complexes with the right properties for these high magnetic fields.

Gadolinium (Gd) complexes have commonly been used as contrast agents since the late 1980s. Parker and colleagues from the UK, Italy and France made a number of Gd complexes and discovered one that gave longer-lasting enhancements to MRI signals than commercial contrast agents. Parker's team used dendrimer technology to couple a Gd complex to sugar-containing groups. 'Preliminary imaging experiments in small animals reveal that the complex is about four times more effective than ProHance, a contrast agent already used in clinical practice,' said Parker. 

Parker suggested that the systems will be suitable for use in vivo; his experiments revealed that the complex is cleared from the blood through the kidneys. Future work will focus on developing analogues in related systems, he said.

Rebecca Lavender