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ST: Strahlen- und Medizinphysik

ST 4: MR - Bildgebung

ST 4.4: Talk

Monday, March 13, 2006, 17:40–17:50, D

Radial Magnetic Resonance Imaging of the Human Lung — •Falko Lohberger, Michael Amann, and Lothar R. Schad — Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, 69120 Heidelberg

In magnetic resonance imaging radial k-space sampling schemes provide very short echo times down to the submillisecond range. Furthermore, radial acquisition techniques are relatively motion insensitive due to central k-space averaging effects. Additionally, short readout times are feasible in radial MRI allowing the acquisition of a set of slices covering the whole lung volume within a single breathhold. In this work, a 2D radial gradient echo technique with angular undersampling was optimized for lung imaging on a 1.5T whole-body MR scanner. On-line data reconstruction was implemented. The k-space readout pattern consisted of a conventional 2D slice encoding and a radial in-plane readout with angular undersampling: P=384 angular projections by S=192 radial samples which resulted in k-space oversampling in the central region and undersampling in the periphery. It is shown that radial sampling increases image quality due to reduced motion artifacts. An echo time of TE=0.57ms provided by the radial sequence yields substantially improved visibility of lung parenchyma and sub-segmental vessels compared to the Cartesian sampling with a four times larger echo time of TE=2.54ms for the same resolution.