Datensatz

Zusammenfassung

In this project, a spiral fast imaging sequence was implemented on a Bruker Avance MR system. Acquisition and processing schemes were developed to measure the experimental k-space trajectories. Since errors in k-space are reflected as errors in the corresponding image, we used different strategies to measure and calculate corrections for deviation of the experimental k-space trajectory from the theoretical one. Even if the k-space trajectories deviate from the theoretical ones, an experimentally measured trajectory can be incorporated in the spiral reconstruction and a reduction of image artifacts can be obtained.
Trajectories were measured according a method using self-encoding gradients (Takahashi et al., 1995). Necessary corrections were deduced from a quantitative comparison of theoretical and experimental data, which can be used to adjust specific parameters in the MR imaging sequence before spiral image acquisition. The corrections included the assessment of baseline, gradient delay, amplitude and timing mismatch.
The influence and extent of different corrections pre- and post-acquistion on the final spiral image quality still remains to be evaluated. KEYWORDS: MRI; fast imaging; Spiral imaging; k-space trajectory;