title: Nonenhanced free-breathing ECG-gated steady-state free precession 3D MR angiography of the renal arteries: comparison between 1.5 T and 3 T.
abstract: OBJECTIVE
  The purpose of our study was to compare the image quality of free-breathing ECG-gated nonenhanced steady-state free precession (SSFP) MR angiography of renal arteries at 1.5 T and 3 T.
  
  
  METHODS
  Twenty volunteers (11 men, nine women; mean age, 23.2 +/- 2.3 years) without a history of renovascular disease participated in the study. Nonenhanced SSFP MR angiography was performed on all subjects at both 1.5 T and 3 T with a maximum interval of 2 weeks between the imaging sessions. The subjective image quality of axial and coronal maximum-intensity-projection reconstructions of four segments (1, abdominal aorta and ostium of renal artery; 2, main renal artery; 3, segmental branches outside renal parenchyma; 4, segmental branches inside renal parenchyma) was evaluated independently by two radiologists using a 4-point scale (4, excellent; 1, nondiagnostic). Relative signal-to-noise ratio, contrast-to-noise ratio, and maximum visible vessel length of the right and left renal arteries also were determined.
  
  
  RESULTS
  No significant difference in image quality at 1.5 T and 3 T was found for segments 1 and 2. The mean image quality for segments 3 and 4 was significantly greater at 3 T (3.88 +/- 0.32, 3.17 +/- 0.70) than at 1.5 T (3.32 +/- 0.73, 2.09 +/- 0.81) (p < 0.001). At 3 T, the maximal vessel length of the right (9.85 +/- 0.82 cm) and left (8.3 +/- 0.79 cm) renal arteries was significantly greater than at 1.5 T (8.94 +/- 1.38 cm and 7.58 +/- 1.18 cm, respectively).
  
  
  CONCLUSIONS
  Performing nonenhanced SSFP MR angiography at 3 T significantly improves visualization of peripheral renal arterial segments in healthy subjects as compared to 1.5 T.
authors.affiliation: Department of Radiology, University Hospital Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany.
authors.forename: Rotem Shlomo
authors.initials: RS
authors.lastname: Lanzman
authors.forename: Patric
authors.initials: P
authors.lastname: Kröpil
authors.forename: Peter
authors.initials: P
authors.lastname: Schmitt
authors.forename: Sonja-Marie
authors.initials: SM
authors.lastname: Freitag
authors.forename: Adrian
authors.initials: A
authors.lastname: Ringelstein
authors.forename: Hans Jörg
authors.initials: HJ
authors.lastname: Wittsack
authors.forename: Dirk
authors.initials: D
authors.lastname: Blondin
mesh_terms: D004562:Electrocardiography; D006801:Humans; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D012077:Renal Artery / Q000033:anatomy & histology*; D018709:Statistics, Nonparametric; D055815:Young Adult