title: Single breathhold noncontrast thoracic MRA using highly accelerated parallel imaging with a 32-element coil array.
abstract: OBJECTIVE
  To evaluate the feasibility of performing single breathhold three-dimensional (3D) thoracic noncontrast MR angiography (NC-MRA) using highly accelerated parallel imaging.
  
  
  METHODS
  We developed a single breathhold NC MRA pulse sequence using balanced steady state free precession (SSFP) readout and highly accelerated parallel imaging. In 17 subjects, highly accelerated noncontrast MRA was compared against electrocardiogram-triggered contrast-enhanced MRA. Anonymized images were randomized for blinded review by two independent readers for image quality, artifact severity in eight defined vessel segments and aortic dimensions in six standard sites. NC-MRA and CE-MRA were compared in terms of these measures using paired sample t- and Wilcoxon tests.
  
  
  RESULTS
  The overall image quality (3.21 ± 0.68 for NC-MRA versus 3.12 ± 0.71 for CE-MRA) and artifact (2.87 ± 1.01 for NC-MRA versus 2.92 ± 0.87 for CE-MRA) scores were not significantly different, but there were significant differences for the great vessel and coronary artery origins. NC-MRA demonstrated significantly lower aortic diameter measurements compared with CE-MRA; however, this difference was not considered clinically relevant (>3 mm difference) for less than 12% of segments, most commonly at the sinotubular junction. Mean total scan time was significantly lower for NC-MRA compared with CE-MRA (18.2 ± 6.0 s versus 28.1 ± 5.4 s, respectively; P < 0.05).
  
  
  CONCLUSIONS
  Single breathhold NC-MRA is feasible and can be a useful alternative for evaluation and follow-up of thoracic aortic diseases.
authors.affiliation: Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA. jian.xu.sz@gmail.com
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.forename: Kelly Anne
authors.initials: KA
authors.lastname: McGorty
authors.forename: Ruth P
authors.initials: RP
authors.lastname: Lim
authors.forename: Mary
authors.initials: M
authors.lastname: Bruno
authors.forename: James S
authors.initials: JS
authors.lastname: Babb
authors.forename: Monvadi B
authors.initials: MB
authors.lastname: Srichai
authors.forename: Daniel
authors.initials: D
authors.lastname: Kim
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Sodickson
mesh_terms: D000328:Adult; D000368:Aged; D001011:Aorta / Q000033:anatomy & histology*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D018810:Magnetic Resonance Angiography / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D015656:Respiratory Mechanics; D012680:Sensitivity and Specificity; D013909:Thorax / Q000033:anatomy & histology* / Q000098:blood supply*; D014159:Transducers; D055815:Young Adult