MICCAI 2013 - LNCS 8149-8151

Self-gated Radial MRI for Respiratory Motion Compensation on Hybrid PET/MR Systems

Robert Grimm¹, Sebastian Fürst², Isabel Dregely², Christoph Forman¹, Jana Maria Hutter¹, Sibylle I. Ziegler², Stephan Nekolla², Berthold Kiefer³, Markus Schwaiger², Joachim Hornegger¹, and Tobias Block⁴

¹Pattern Recognition Lab, FAU Erlangen, Erlangen, Germany

²Department of Nuclear Medicine, TU Munich, Munich, Germany

³Siemens Healthcare MR, Erlangen, Germany

⁴Department of Radiology, NYU Langone Medical Center, New York City, NY, USA

Abstract. Accurate localization and uptake quantification of lesions in the chest and abdomen using PET imaging is challenging due to the respiratory motion during the exam. The advent of hybrid PET/MR systems offers new ways to compensate for respiratory motion without exposing the patient to additional radiation. The use of self-gated reconstructions of a 3D radial stack-of-stars GRE acquisition is proposed to derive a high-resolution MRI motion model. The self-gating signal is used to perform respiratory binning of the simultaneously acquired PET raw data. Matching -maps are generated for every bin, and post-reconstruction registration is performed in order to obtain a motion-compensated PET volume from the individual gates. The proposed method is demonstrated in-vivo for three clinical patients. Motion-corrected reconstructions are compared against ungated and gated PET reconstructions. In all cases, motion-induced blurring of lesions in the liver and lung was substantially reduced, without compromising SNR as it is the case for gated reconstructions.

LNCS 8151, p. 17 ff.

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