title: Use of 2D sensitivity encoding for slow-infusion contrast-enhanced isotropic 3-T whole-heart coronary MR angiography.
abstract: OBJECTIVE
  The purpose of this study was to improve the blood-pool signal-to-noise ratio (SNR) and blood-myocardium contrast-to-noise ratio (CNR) of slow-infusion 3-T whole-heart coronary MR angiography (MRA).
  
  
  METHODS
  In 2D sensitivity encoding (SENSE), the number of acquired k-space lines is reduced, allowing less radiofrequency excitation per cardiac cycle and a longer TR. The former can be exploited for signal enhancement with a higher radiofrequency excitation angle, and the latter leads to noise reduction due to lower data-sampling bandwidth. Both effects contribute to SNR gain in coronary MRA when spatial and temporal resolution and acquisition time remain identical. Numeric simulation was performed to select the optimal 2D SENSE pulse sequence parameters and predict the SNR gain. Eleven patients underwent conventional unenhanced and the proposed 2D SENSE contrast-enhanced coronary MRA acquisition. Blood-pool SNR, blood-myocardium CNR, visible vessel length, vessel sharpness, and number of side branches were evaluated.
  
  
  RESULTS
  Consistent with the numeric simulation, using 2D SENSE in contrast-enhanced coronary MRA resulted in significant improvement in aortic blood-pool SNR (unenhanced vs contrast-enhanced, 37.5 ± 14.7 vs 121.3 ± 44.0; p < 0.05) and CNR (14.4 ± 6.9 vs 101.5 ± 40.8; p < 0.05) in the patient sample. A longer length of left anterior descending coronary artery was visualized, but vessel sharpness, coronary artery coverage, and image quality score were not improved with the proposed approach.
  
  
  CONCLUSIONS
  In combination with contrast administration, 2D SENSE was found effective in improving SNR and CNR in 3-T whole-heart coronary MRA. Further investigation of cardiac motion compensation is necessary to exploit the SNR and CNR advantages and to achieve submillimeter spatial resolution.
authors.affiliation: Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Yu
authors.forename: Ingo
authors.initials: I
authors.lastname: Paetsch
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schnackenburg
authors.forename: Eckart
authors.initials: E
authors.lastname: Fleck
authors.forename: Robert G
authors.initials: RG
authors.lastname: Weiss
authors.forename: Matthias
authors.initials: M
authors.lastname: Stuber
authors.forename: Cosima
authors.initials: C
authors.lastname: Jahnke
mesh_terms: D019295:Computational Biology; D003198:Computer Simulation; D003287:Contrast Media / Q000008:administration & dosage; D003327:Coronary Disease / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007262:Infusions, Intravenous; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000008:administration & dosage / Q000031:analogs & derivatives; D008875:Middle Aged; D009942:Organometallic Compounds / Q000008:administration & dosage
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine