Breath-hold single-dose gadolinium-enhanced three-dimensional MR aortography: Usefulness of a timing examination and MR power injector

PURPOSE: To determine the usefulness of a timing examination performed with 1 mL gadopentetate dimeglumine administered with a magnetic resonance (MR) power injector at single-dose three-dimensional (3D) MR aortography. MATERIALS AND METHODS: 3D fast imaging with steady-state precession (repetition time [msec]/echo time [msec] = 5.0/2.0, with 50° flip angle) was performed in 30 patients after administration of 0.1 mmol/kg gadopentetate dimeglumine. In 15 inpatients, a power injector was used and a timing examination was performed (experimental group). In 15 outpatients, manual injection was used and a timing examination was not performed (control group). In the timing examination, 1 mL gadopentetate dimeglumine was followed with 15 mL saline, both at 2 mL/sec, during axial turbo fast low- angle shot imaging (11/4.2/300 [inversion time {msec}], with a 15° flip angle); one image was obtained every 2 seconds for 60 seconds. Aortic signal- to-noise ratios (S/Ns) and contrast-to-noise ratios (C/Ns) were determined on images obtained in the two groups. RESULTS: In the timing examinations, aortic S/N increased significantly (902% ± 517 [P < .001]) and was sufficient to help determine the timing of arterial enhancement. Findings on experimental images were superior to those on control images (S/N, 29.8 vs 20.5 [P = .003]; C/N, 23.8 vs 12.8 [P < .001], respectively). The time to perform procedures and calculations at the timing examination added a mean of 4.5 minutes to each examination. CONCLUSION: The combined use of a power injector and a timing examination improved S/Ns and C/Ns at breath-hold single-dose gadolinium-enhanced 3D MR aortography.