Relationship between the degree of abdominal wall movement and the image quality of contrast-enhanced MRI: semi-quantitative study especially focused on the occurrence of transient severe motion artifact.

ABSTRACT

PURPOSE: To reveal the relationship between abdominal movement and artifact, and to reveal if the transient artifact in arterial phase is caused by transient abdominal movement (TAM) in contrast-enhanced (CE) MRI. MATERIALS AND METHODS: 325 CE-MRI series (206 with EOB and 119 with EGCM) were included. The abdominal movement was classified into three groups by respiratory bellows waveform (= bellows grade, BG 1-3), and MR image quality (= artifact score, AS) was graded 1-5 for the precontrast, arterial and portal venous phase, respectively. The relationship between the BG and AS was evaluated. The occurrence of transient artifact in arterial phase was compared to the degree of TAM. RESULTS: In the acquisitions with BG3, all images showed AS of > 2, while no images had AS of > 4 in the acquisitions with BG1. Numbers of transient artifact in the arterial phase with no-abdominal movement (NAM), mild-TAM, severe-TAM were 0 of 120, 4 of 27, 7 of 8 in EOB and 0 of 91, 1 of 4, 0 of 0 in EGCM, respectively. CONCLUSION: Image quality is highly correlated with abdominal movement. Moreover, artifact in arterial phase was not observed in NAM, which indicated abdominal movement is the direct cause of artifact.