Quantitative MRI of the brain is an attractive and challenging undertaking that aims to extract physical parameters from native MRI images. Quantitative assessment of cerebral tissue changes present the advantage of being unbiased compared to the more traditional non-quantitative description. Second, the quantitative approach is well-suited to statistical modelling, and systematic image analysis approaches such as the construction of brain atlases. Finally, the tissue intrinsic images produced from quantitative imaging techniques offer new possibilities in longitudinal as well as cross-sectional studies.
Proton MRI is sensitive to the distribution and the mobility of the water molecules in tissue and is also strongly influenced by the chemical environment, such as the presence of paramagnetic substances. The measured distribution of water relates almost directly to the water content of the tissue, that is, the number of water molecules per unit volume of tissue. On the other hand, the mobility of the molecules and the chemical environment give rise to two tissue specific relaxation times, the longitudinal (T1) and transversal (T2) relaxation times.
Our group focuses on the measurement of the tissue relaxation parameters T1 and T2 as well as water content. To achieve this aim, appropriate MRI sequences must be developed and / or adapted in order to provide efficient and accurate methods that might routinely be applicable in the clinic. Therefore, projects are placed at the interface between basic MR physics, software development and the application of developed methods in the context of clinical studies and/or routine diagnosis. Based on cooperations with the University Hospital Aachen and the Heinrich Heine University of Duesseldorf, the quantitative imaging methods invented in Jülich are applied in neuroscientific research and have already produced novel results. Current studies focus on the quantitative imaging of brain oedema in patients with liver cirrhosis and hepatic encephalopathy, brain water content dialysis patients, and the quantitative imaging of MS lesions.