| Zusammenfassung |
Magnetic resonance imaging is a non-invasive imaging modality for the diagnosis of cardiovascular diseases. A broad range of
diagnostic parameters can be obtained within a single examination, including information about morphology, physiology and tissue
viability. Currently, qualitative contrast-enhanced imaging is the gold standard for the detection of myocardial pathologies by visual
assessment. In such qualitative approaches healthy myocardium has to be present in the image to have a contrast between healthy
myocardium and pathological areas. Therefore, only focal myocardial defects can be accurately diagnosed. Recently, it has been
shown that T1-relaxation times can be used to characterize myocardial pathologies even if they are not localized but affect the
entire myocardium (diffuse disease). Furthermore, T1 serves as a tissue specific quantitative diagnostic parameter which ensures
comparability of different scans and allow for multi-centre studies and monitoring of disease progression or treatment response
even over a long period of time. T1 mapping relies on the acquisition of a number of qualitative T1-weighted images to
encodetherecoveryoflongitudinalmagnetization, resultinginlongacquisitiontimes. However, a cardiac examination consists of multiple
scans in order to obtain all information needed for diagnostics, such as cardiac function, leaving little room for additional scan time.
This hinders itsapplicationinclinicalpractice. Therefore,fastandrobust T1 mappingtechniqueshavetobe developed, without prolonging
examination time or loss in accuracy or precision. Furthermore, cardiac T1 mapping is very challenging because of cardiac and
respiratory motion. In this thesis, a multiparametric magnetic resonance imaging technique was developed to increase the efficiency
of data acquisition. Using this approach, accurate T1 maps and functional images were obtained simultaneously without
prolongation of the scan time. HighresolutionT1 mappingwasrealizedbyadvancedmodel-basedimagereconstructionthatutilizes prior
knowledge of T1 recovery to obtain accurate T1 estimation. By integration of cardiac motion correction techniques based on the
reconstructed functional images, the scan duration was reduced by 50%, while precision of T1 mapping was increased. The
presented techniques were evaluated in phantoms and feasibility was shown in healthy volunteers and in patients. The imaging
approaches proposed in this thesis have been demonstrated to hold great promise for simultaneous imaging of multiple clinically
relevant parameters by efficient data sampling and advanced image reconstruction methods. The multiparametric approach could
be important for future directions in cardiovascular magnetic resonance imaging, because the fast and contrast-free examination
allows for quantitative imaging in a short examination time. |
