Influence of injection rate in determining the development of artifacts during the acquisition of dynamic arterial phase in Gd-EOB-DTPA MRI studies

Objective: To assess whether different Gd-EOB-DTPA injection rates could influence the development of artifacts during the arterial phase of liver MRI studies. Materials and methods: All Gd-EOB-DTPA liver MRI studies performed for different clinical indications at a single tertiary referral center were retrospectively evaluated. Each examination was acquired on a 1.5T scanner with T1 In- and Out-of-Phase, T2 with and without fat-saturation, DWI, and 3D-T1 fat-sat dynamic sequences. Patients were divided into two groups according to the injection rate (1ml/s and 1.5ml/s). A single radiologist recorded the presence or absence of artifacts during different acquisition phases, respectively: (1) all examination; (2) only during the arterial phase; (3) only during the portal-venous phase; (4) both in arterial and portal-venous phases. From a total of 748 MRI studies performed, 229 were excluded due to the presence of artifacts during the entire examination. The remaining 519 MRI studies were divided into two groups according to the injection rate. Results: The first group (flow rate = 1ml/s) was composed by 312 (60.1%) patients and the second group (flow rate = 1.5ml/s) by 207 (39.9%) patients. In the first group, 2 (0.6%) patients showed artifacts in all dynamic sequences; 13 (4%) only in the arterial phase, 16 (5%) only in the portal-venous phase, and 38 (12%) both in arterial and portal-venous phases; a total of 243 (78%) showed no artifacts. In the second group, 3 (1.5%) patients had artifacts in all dynamic sequences, 82 (40%) only in the arterial phase, 20 (10%) only in the portal-venous phase, and 53 (25%) both in arterial and portal-venous phases; a total of 49 (23.5%) showed no artifacts. A significant difference between the two groups regarding the absence of artifacts in all examination and the presence of artifacts only during the arterial phase was found (p < 0.001). Conclusion: The development of artifacts during the arterial phase of Gd-EOB-DTPA liver MRI studies could be related to the injection rate and its reduction may help to decrease the incidence of artifacts.