The contrast of MR images is principally determined by the parameters of an MR acquisition (sequence parameters) and by intrinsic tissue characteristics such as proton density, longitudinal (T1) and transversal (T2) relaxation times. Quantitative MRI provides information on these intrinsic tissue parameters using so-called mapping techniques. These yield highly valuable diagnostic information independent of external parameters (vendor of MR scanner, sequence parameters, etc.).

The main challenge of mapping techniques is the long acquisition time, which makes them difficult to apply in standard clinical practice. Novel data acquisition and image reconstruction methods can overcome this problem.

The majority of quantitative MRI techniques record multiple images with different acquisition parameters. After image reconstruction, a signal model is fitted to the images on a pixel-by-pixel basis in order to obtain the quantitative tissue parameters.

During image reconstruction, model-based reconstruction approaches utilise information about the behaviour of magnetisation over time (e.g. T1-recovery after an inversion pulse) as prior knowledge. This additional information allows for a more accurate reconstruction and directly yields quantitative tissue parameters. In addition, this technique facilitates more flexible and efficient data acquisition.

In cardiac MRI, T1-mapping is commonly used to assess the viability of the myocardium. A wide range of different diseases such as myocardial infarction and fibrosis lead to changes in the T1-times of the myocardium and can therefore be detected and diagnosed. Faster and more accurate mapping approaches hold the promise of an earlier and more precise diagnosis leading to improved treatment outcomes.

The main challenge of the majority of cardiac MRI techniques is physiological motion of the heart due to breathing and the heart beat. To overcome this problem, we are working on novel approaches for motion-compensated image reconstruction to achieve an accurate assessment of quantitative tissue parameters independent of any physiological motion.

This development of novel techniques is being carried out in close collaboration with Prof. Dr. Jeanette Schulz-Menger, head of the MRI group at the “Experimental and Clinical Research Center“ (ECRC) at Charité Berlin.