Retrospective Breathing Motion Compensation for MRI with Continuously Moving Table

Breathing motion causes severe artifacts in Magnetic Resonance Imaging (MRI), which are usually avoided using either breath-holding during the acquisition or gating or triggering techniques while the patient is breathing freely. In MRI with continuously moving table the patient is moved through the magnet during the data acquisition, thereby allowing for time efficient coverage of arbitrary large body regions. Due to the continuous table motion standard breathing motion compensation techniques are not applicable here. In this work a retrospective compensation technique for abdominal breathing motion in moving table MRI is proposed, which reconstructs artifact free images from data acquired during free breathing. For each slice position multiple motion consistent snapshots of arbitrary breathing states are acquired and subsequently combined consistently using a combination of rigid and deformable slice-to-volume registration. Typical breathing motion induced artifacts such as ghosting, blurring or misalignments of organs occurring if data from different breathing states is inconsistently combined are avoided. The proposed method significantly extends a previous approach which aimed only at the suppression of ghosting artifacts in MRI with continuously moving table.