Studienarbeiten

Numerical flow phantoms play an important role for the development and comparison of imaging techniques. In order to be able to assess performance and robustness of such methods it is necessary to have data with known reference values, which is often not possible in-vitro or in-vivo.

Flow measurements using MRI offer the possibility to assess blood flow non-invasively with a high spatial and temporal resolution. However, measurements in the larger blood vessels are affected by motion due to respiration and the contraction of the heart itself. Techniques to compensate for motion include breathholding, gating and retrospective motion correction. A quantitative comparison of such methods proves difficult in-vivo, as the data cannot be acquired in the same scan and the true values are not known.

For the simulation of cardiac and respiratory motion, a realistic phantom based on 4D CT data was adopted. As CT does not provide functional information, blood flow has to be simulated using Computational Fluid Dynamics (CFD).

It is the objective of this project to extend the existing XCAT phantom to include fluid flow in the larger blood vessels. To this end, CFD simulations will be employed to obtain realistic flow fields in the aorta and the arteries in the neck and subsequently incorporated in the model. Undersampled data acqusition will be simulated to assess flow field errors as a function of undersampling rate and based signal-to-noise ratio.