Research focus
The electrical conductivity of the brain may be used for diagnostic purposes, and to improve the accuracy of different biomedical imaging techniques, i.e. transcranial current stimulation, transcranial magnetic stimulation, electroencephalography, and magnetoencephalography source localization.
Magnetic Resonance Electrical Impedance Tomography (MREIT) is an emerging imaging modality, which may reconstruct the current flow and electrical conductivity inside brain. In MREIT, external electrical current is injected to the brain and this current causes small magnetic field changes inside the brain. The sensitivity of MREIT directly scales with the signal-to-noise ratio of MR image and the sensitivity of the employed MR sequences in measuring the small magnetic field changes, caused by the weak injected currents. Up to now, different MRI pulse sequences, such as gradient echo, spin echo, echo-planar imaging etc., have been used in MREIT. However, the sensitivity of MREIT is still not enough for in-vivo human brain MREIT.
The PhD project aims directly at the main challenge in MREIT, namely to strongly boost up the sensitivity and to optimize the MR sequences to realize in-vivo human brain MREIT. The project will systematically explore the sensitivity of alternative and currently used MR sequences, namely multi-echo spin echo, steady-state free precession free-induction decay, and balanced steady state free precession (bSSFP). The current induced magnetic field will be measured with the newly developed approach, and will then be compared with simulation results, which are based on realistic volume conductor models and Finite Element methods, as already developed. This will be used to achieve the second project goal, namely to directly validate the head modeling approaches by means of MREIT measurements.
The project is carried out from both DTU Electrical Engineering and Danish Research Center for Magnetic Resonance at Copenhagen University Hospital Hvidovre, providing access to scanners. It also involves development of hardware, eg. electronics for real-time processing of signals acquired during MRI.
Scientific output
Find Cihan's publications at DTU's online research database ORBIT.
Funding
The project is funded by Lundbeck Foundation.
Supervisors
Associate Professor Axel Thielscher and Associate Professor Lars G. Hanson.
Project period
September 2014 - August 2017.