Projects at the Danish Research Centre for Magnetic Resonance

Transcription

1 Projects at the Danish Research Centre for Magnetic Resonance Five projects involving Magnetic Resonance Imaging (MRI) Hvidovre Hospital Example: [1-13C]Pyruvate signal enhanced by ~50,000x!

2 Magnetic Resonance Imaging, MRI Flexible diagnostic and research tool Multidisciplinary! MR technicians, Radiologist, Physicists, Engineers, Neurologists, Psychiatrists, Physicians, Psychologists, (Human) Biologists, Humanists, Computer Scientists, Linguists, Chemists, Complex image analysis methods/computer power

3 Magnetic Resonance Imaging, MRI Nuclei in body are aligned so the patient becomes magnetic. Radiowaves are used to make the magnetic needle swing. Radiowave signals from oscillating dipoles are detected.

4 MR projects BSc/MSc-project: Probing water molecules transported across cell membranes using diffusion MRI Supervisors: DTU : Lars G. Hanson DRCMR : Tim Dyrby, Lise Vejby Søgaard, Henrik Lundell

5 Probing water molecules transported across cell membranes using diffusion MRI Diffusion MRI Measures the random motion of water molecules along a specific direction in tissue. Tissue microstructure Across axons Different kind of microstructural restrictions exist 10 µm Along axons Molecules that are: Inside Axons (blue) Outside (green) Cross membrane (red)

6 Probing water molecules transported across cell membranes using diffusion MRI To day, using a conventional PGSE (pulse gradient spin echo) sequence all compartments are SUMMED to the measured signal. Cell permeability? + + PGSE Small signal Complex model Yes, but noisy The aim using a double- PGSE can we then FILTER away i.e. the outside compartment (green)? + d-pgse Max. signal Simple model Yes - possible

7 MR projects MSc-project: Maturational changes in hippocampus shape in children and adolescents Supervisors: DTU : Rasmus Larsen DRCMR : Arnold Skimminge, William Baaré

8 Maturational changes in hippocampus shape in children and adolescents Learning, Memory Spatial navigation Stress Emotional functioning Neurogenesis Hippocampal subfields mapped onto the hippocampal surface Ballmaier et al, Am J Psychiatry 2008 Hippocampus Hjernens Udvikling hos Børn og Unge Age

9 MR projects Bsc/MSc-project: EEG measured during MRI: Validation of a new acquisition method Supervisors: DTU : Lars Hanson DRCMR : Kristoffer Madsen, Christian G. Hanson

10 EEG measured during MRI: Validation of a new acquisition method fmri for functional mapping: Bold-Dependent-Oxygen-Level-Dependent signal (BOLD) Intensity variations over time reflect activity: Deoxy-haemoglobin is paramagnetic (decreases the MR signal). Hence BOLD is a very indirect measure of activity, with good spatial resolution but with low temporal resolution (second). fmri can only tell where activity is, if we know when it occurs (unrelated signal changes dominate). Simultaneous EEG can help, but there are technical challenges

11 EEG measured during MRI: Validation of a new acquisition method EEG corrupted by MRI Noise from field changes and pulse New method for simultaneous EEG and fmri acquisition patented at DRCMR: The scanner is used to record both. Scanner noise reduced by orders of magnitude. Other advantages: Data handling, price, perfect sync. Needed: Further development and validation. Magstripe MRI principle

12 MR projects Bsc/MSc-project: Design and testing of bench top NMR spectrometer Supervisors: GE Healthcare : Jan Henrik Ardenkjær-Larsen KU/DTU : Lars Hanson

13 BSc/MSc-project: Using MR-scanning to image macro-molecules in theimaging: brain. Metabolic Hyperpolarized C13 Example: [1-13C]Pyruvate signal enhanced by ~50,000x! The hyperpolarized molecule is injected into an animal and metabolized into products that are imaged Project: Design and testing of bench top NMR spectrometer - Build detection coils (1-10 MHz) - Build preamp - Develop software

14 MR projects Bsc-project: Design of capacitive helium level sensor and control loop Supervisors: GE Healthcare : Jan Henrik Ardenkjær-Larsen KU/DTU : Lars Hanson

15 Project: Design of capaci-ve helium level sensor and control loop. Construct and implement a liquid helium sensor to regulate the level of helium in cryostat. Allen-Bradley resistors