title: Spiral magnetic resonance coronary angiography--direct comparison of 1.5 Tesla vs. 3 Tesla.
abstract: BACKGROUND
  MR coronary angiography (MRCA) has been demonstrated successfully at 3 Tesla (T). However, the advantages remain unclear. No systematic comparison of MRCA between 1.5 T and 3 T has been performed. Therefore, anatomic coverage, image quality, signal-to-noise ratio (SNR), contrast-to-noise ration (CNR), and susceptibility artifacts were compared in 23 subjects.
  
  
  RESULTS
  Identical real-time (RT) and high-resolution (HR) sequences were implemented on the GE 1.5 T (Signa Twinspeed) and 3.0 T (Signa VH/i) whole body systems (GE, Milwaukee, WI). Both scanners were equipped with high-performance gradient systems capable of 40 mT/m peak amplitude and 150 mT/m/ms slew rate. Real-time localization of the coronary arteries was followed by a cardiac-gated, breath-hold HR sequence. Twenty-three subjects were recruited consecutively and underwent both 3 T and 1.5 T MRCA within one week. Coronary coverage based on the number of coronary segments visualized, image quality using a grading scale, SNR, CNR, and presence of susceptibility artifacts were analyzed. A significant improvement in SNR (47%), CNR (30%), and image quality were seen in 3 T. However, a significant increase in susceptibility artifacts was also noted.
  
  
  CONCLUSIONS
  MRCA at 3 T significantly improves SNR, CNR, and image quality at the expense of susceptibility artifacts. Further optimization of the imaging parameters at 3 T may facilitate clinical implementation of MRCA.
authors.affiliation: Department of Medicine, Division of Cardiovascular Medicine, Stanford University, Stanford, California 94305-5233, USA. pyang@cvmed.stanford.edu
authors.forename: Phillip C
authors.initials: PC
authors.lastname: Yang
authors.forename: Patricia
authors.initials: P
authors.lastname: Nguyen
authors.forename: Ann
authors.initials: A
authors.lastname: Shimakawa
authors.forename: Jean
authors.initials: J
authors.lastname: Brittain
authors.forename: John
authors.initials: J
authors.lastname: Pauly
authors.forename: Dwight
authors.initials: D
authors.lastname: Nishimura
authors.forename: Bob
authors.initials: B
authors.lastname: Hu
authors.forename: Michael
authors.initials: M
authors.lastname: McConnell
mesh_terms: D000328:Adult; D000368:Aged; D016477:Artifacts; D002140:California; D003199:Computer Systems; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000175:diagnosis; D003331:Coronary Vessels / Q000033:anatomy & histology / Q000473:pathology; D004198:Disease Susceptibility; D005260:Female; D006801:Humans; D007089:Image Enhancement; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged