A new class of MRI (magnetic resonance imaging) contrast agents developed by scientists in the UK is promising to deliver clearer images in less time. ‘In any NMR experiment you are chasing sensitivity. We have enhanced the intrinsic ability to observe an MRI probe signal by a factor of 20,’ explains David Parker of Durham University who led the study.
MRI is used in clinical settings to image the inside of the body. It uses strong magnetic fields and radio waves to probe the behaviour of nuclei that possess nuclear spin. Chemical shifts from proton NMR normally fall between 0–12ppm but water and fat resonate at 4.7 and 1.3ppm, respectively, and can overlap with MRI probe signals. Parker’s new probes shunt the spectral window of MRI scans well away from these interfering signals, a concept he describes as ‘moving the goalposts’. The probes consist of lanthanide complexes with a t-butyl group and the distance between the lanthanide and t-butyl group was fixed to optimise the rate of decay of the t-butyl signal as well as move its chemical shift. Data acquisition was possible just a few minutes after administering the probe and the signal from the lanthanide induced relaxation of the nine protons in the t-butyl groups has been shifted by up to 80ppm.
Proton NMR spectra showing the shifted t-butyl resonances in some of the new dysprosium and thulium complexes
Read the full article in Chemistry World»
Read the original journal article in Chemical Science:
Moving the goal posts: enhancing the sensitivity of PARASHIFT proton magnetic resonance imaging and spectroscopy
Peter Harvey, Andrew M. Blamire, J. Ian Wilson, Katie-Louise N. A. Finney, Alexander M. Funk, P. Kanthi Senanayake and David Parker
Chem. Sci., 2013,4, 4251-4258, DOI: 10.1039/C3SC51526E
