Multichannel transmission and ultra high field enhance spatial resolution
Since last year, significant improvements in image resolution from 7-Tesla ultra high field magnetic resonance (UHF MR) scanners have been achieved by replacing the multichannel radio frequency (RF) system of four coils with 16 coils. Compared to MR systems in clinical use (1.5 and 3-T scanners with their common body coil) the current multi-channel#transmission in 7-T increases the image resolution by factor five. ‘It’s like transforming a 10 megapixels camera into one with 50 megapixels,’ explained Prof Thoralf Niendorf, one of the event-organisers and head of the Berlin Ultra High Field Facility (B.U.F.F.) at the MDC, where he and his team are currently working on a 32 coil-system.
Imaging the ‘forgotten’ right ventricle
In combination with the MR stethoscope, an acoustic cardiac triggering device (presented at last year‘s meeting) the enhanced resolution of multichannel system will provide improved imaging of the heart. Prof. Jeannette Schulz- Menger, co-organiser of the meeting and cardiologist at the Charité University Medicine and the Helios Clinic, presented the first images of the right ventricle of hitherto unachieved quality – elusive due to sensitivity and spatial resolution constraints present at lower field strength.
The brain: Columns and layers
For a long time, brain studies at 7-T studied only small regions in great detail. ‘Now technical developments have made it possible to examine the whole brain with a high image quality and very high spatial resolution’, allowing the examination of ‘activation patterns at the spatial level of the building blocks of computational architecture: the cortical layers and columns’, explained Professor David G Norris, from the Donders Centre for Cognitive Neuro-imaging at Radboud University in Nijmegen, The Netherlands, during his talk. This development promises better understanding of psychiatric diseases, explained Professor Kamil Ugurbil, from the Centre for Magnetic Resonance Research (CMRR), University of Minnesota.
Exciting possibilities in UHF MR research were outlined by Professor Daniel K Sodickson, from New York University, USA. ‘Research will involve extracting unique information that currently resides in what are now seen as UHF artefacts – namely the distortions of electromagnetic fields and hence of MR images caused by the presence of tissue.’
Molecular MR imaging
A new topic during the conference was molecular MR imaging, enabling imaging on a cellular and even sub-cellular, i.e. microscopic scale. Proton imaging is no longer the ‘one and only’, as Prof Niendorf explained in an interview. ‘We promote the so called heteronuclear imaging, using fluorine atoms, for example, but also sodium, carbon or phosphor nuclei.’ A recent result, from an independent research group, set up in late summer of 2010 at the MDC,
and led by molecular biologist Sonia Waiczies, was able to detect and neatly portray the lymphatic system of mice with the help of injected fluorine-marked cells. Even sentinel lymph nodes could be distinctly identified, which will certainly be of great use for future early-stage cancer diagnosis.
Event organisers: Prof Thoralf Niendorf from the B.U.F.F. at the MDC, Bernd Ittermann from the PTB, a national metrology institute provided scientific and technical services, and Prof Jeannette Schulz-Menger, Cardiologist from the Charité, University Medicine and Helios Clinic.