title: Contrast-enhanced specific absorption rate-efficient 3D cardiac cine with respiratory-triggered radiofrequency gating.
abstract: OBJECTIVE
  To investigate the use of radiofrequency (RF) gating in conjunction with a paramagnetic contrast agent to reduce the specific absorption rate (SAR) and increase the blood-myocardium contrast in balanced steady-state free precession (bSSFP) 3D cardiac cine.
  
  
  METHODS
  RF gating was implemented by synchronizing the RF-excitation with an external respiratory sensor (bellows), which could additionally be used for respiratory gating. For reference, respiratory-gated 3D cine images were acquired without RF gating. Free-breathing 3D cine images were acquired in eight healthy subjects before and after contrast injection (Gd-BOPTA) and compared to breath-hold 2D cine.
  
  
  RESULTS
  RF-gated 3D cine reduced the SAR by nearly 40% without introducing significant artifacts while providing left ventricle (LV) measurements similar to those obtained with 2D cine. The contrast-to-noise ratio (CNR) was significantly higher for 3D cine compared to 2D cine, both before and after contrast injection; however, no statistically significant CNR increase was observed for the postcontrast 3D cine compared to the precontrast acquisitions.
  
  
  CONCLUSIONS
  Respiratory-triggered RF gating significantly reduces SAR in 3D cine acquisitions, which may enable a more widespread clinical use of 3D cine. Furthermore, CNR of 3D bSSFP cine is higher than of 2D and administration of Gd-BOPTA does not improve the CNR of 3D cine.
authors.affiliation: Cardiovascular Division, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA. markus.henningsson@kcl.ac.uk
authors.forename: Markus
authors.initials: M
authors.lastname: Henningsson
authors.forename: Raymond H
authors.initials: RH
authors.lastname: Chan
authors.forename: Beth
authors.initials: B
authors.lastname: Goddu
authors.forename: Lois A
authors.initials: LA
authors.lastname: Goepfert
authors.forename: Reza
authors.initials: R
authors.lastname: Razavi
authors.forename: Rene M
authors.initials: RM
authors.lastname: Botnar
authors.forename: Tobias
authors.initials: T
authors.lastname: Schaeffter
authors.forename: Reza
authors.initials: R
authors.lastname: Nezafat
mesh_terms: D000328:Adult; D016477:Artifacts; D003287:Contrast Media / Q000008:administration & dosage*; D003971:Diastole / Q000502:physiology; D005240:Feasibility Studies; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008536:Meglumine / Q000031:analogs & derivatives*; D009942:Organometallic Compounds; D011846:Radio Waves; D012016:Reference Values; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D013599:Systole / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine