Does transient arterial-phase respiratory-motion-related artifact impact on diagnostic performance? An intra-patient comparison of extracellular gadolinium versus gadoxetic acid.

OBJECTIVE To compare the frequency of transient arterial-phase respiratory-motion-related artifacts in liver MRI after extracellular gadolinium and gadoxetic acid injection, and to determine the impact of these artifacts on the detection of focal areas of enhancement on arterial-phase images. MATERIALS AND METHODS Intra-patient comparison of 82 cirrhotic patients who prospectively underwent liver MR with extracellular gadolinium and with gadoxetic acid within 1 month. Two readers independently assessed the quality of dynamic T1-weighted MR images (pre-contrast, arterial, and portal-venous phases), rating respiratory-motion-related artifacts on four-point scale (0 [none]-3 [non-diagnostic]). We dichotomized these assessments, which were compared using McNemar's test, defining transient arterial-phase respiratory-motion-related artifacts as a study with a pre-contrast score < 2 and arterial-phase score ≥ 2. Readers also recorded whether at least one focal area of enhancement ≥ 10 mm on arterial phase was present. RESULTS The quality of arterial-phase images was worse when obtained after gadoxetic acid than after extracellular gadolinium (p < 0.01), and transient arterial-phase respiratory-motion-related artifacts were more common after gadoxetic acid than after extracellular gadolinium (p < 0.02). At least one area of arterial-phase enhancement ≥ 10 mm was detected more often after extracellular gadolinium than after gadoxetic acid. We observed significant differences on the comparison of the distributions of the presence of arterial-phase artifacts against the presence of arterial-phase enhancement ≥ 10 mm between the two contrast agents (p < 0.0001). CONCLUSION In cirrhotic patients, transient arterial-phase respiratory-motion-related artifacts are more common after gadoxetic acid than after extracellular gadolinium. Worse detection of arterial-phase enhancement on gadoxetic acid is only partly due to these artifacts. KEY POINTS • In a patient-by-patient analysis, the quality of arterial-phase liver MR images was significantly worse with gadoxetic acid than with extracellular gadolinium. • The frequency of transient arterial-phase artifacts was significantly higher after gadoxetic acid injection than after extracellular gadolinium injection. • Differences in the detection of areas of arterial-phase enhancement between MRI studies done with extracellular gadolinium and those done with gadoxetic acid might not be related only to image quality.