High Field Magnetic Resonance Imaging

High field Magnetic Resonance offers unique opportunities for revealing new insight into the relationship between structure and function of the human body.

Our research on high-field Magnetic Resonance (MR) Imaging is conducted from both DTU and Danish Research Centre for Magnetic Resonance (DRCMR) at Copenhagen University Hospital Hvidovre where a 7 tesla MR system is available.

We strive to provide state-of-the-art sequences and protocols, which take full advantage of 7T MR. MR systems operating at fields of 7T or above pose a series of technical challenges for reaching the full potential of the systems:

  • The improved signal-to-noise at 7T allows submillimeter structural and functional image resolution which offers new insights into the understanding of the organization and processes of the body in health and disease. However, a good compensation of subject motion is required to avoid image degradation, which would defeat the purpose of ultra-high resolution imaging. We work on fast image readout approaches and navigator-based correction methods to reduce the effects from motion and the increased physiological noise we unfortunately experience at higher field strength.
  • The higher radiofrequency (RF) at 7T causes strong interactions between the electromagnetic fields and the human body, which makes optimal RF control challenging within the allowed specific absorption rate (SAR) levels using traditional transmit approaches. Our solution is to develop more advanced excitation approaches and to use novel multi-transmit RF technologies available on our state-of-the-art equipment. These new transmit concepts will allow highly improved RF distributions in the human body, and thereby deliver superior image quality at safe SAR levels.
  • Controlling motion and RF requires confinement of inhomogeneities and fluctuations in the main B0 field. We therefore work on advanced shim and dephasing techniques to not only achieve an ideal homogeneous field, but also to take advantage of being able to control the field temporally during the sequences. We exploit this to make novel zoom imaging methods, to exclude unwanted tissue such as fat as well as in advanced RF pulse designs.

Contact

Esben Thade Petersen
Associate Professor
DTU Electrical Engineering
http://www.cmr.elektro.dtu.dk/Research/High-Field-MRI
18 NOVEMBER 2017