title: Four-dimensional flow-sensitive MRI of the thoracic aorta: 12- versus 32-channel coil arrays.
abstract: OBJECTIVE
  To evaluate the performance of four-dimensional (4D) flow-sensitive MRI in the thoracic aorta using 12- and 32-channel coils and parallel imaging.
  
  
  METHODS
  4D flow-sensitive MRI was performed in the thoracic aorta of 11 healthy volunteers at 3 Tesla (T) using different coils and parallel imaging (GRAPPA) accelerations (R): (i) 12-channel coil, R = 2; (ii) 12-channel coil, R = 3; (iii) 32-channel coil, R = 3. The quantitative analysis included SNR, residual velocity divergence and length and curvature of traces (streamlines and pathlines) as used for 3D flow visualization. In addition, semi-quantitative image grading was performed to assess quality of phase-contrast angiography and 3D flow visualization.
  
  
  RESULTS
  Parallel imaging with an acceleration factor R = 3 allowed to save 19.5 ± 5% measurement time compared with R = 2 (14.2 ± 2.4 min). Acquisition using 12 channels with R = 2 and 32 channels with R = 3 produced data with significantly (P < 0.05) higher quality compared with 12 channels and R = 3. There was no significant difference between 12 channels with R = 2 and 32 channels with R = 3 but for the depiction of supra-aortic branches where the 32-channel coil proved superior.
  
  
  CONCLUSIONS
  Using 32-channel coils is beneficial for 4D flow-sensitive MRI of the thoracic aorta and can allow for a reduction of total scan time while maintaining overall image quality.
authors: Department of Radiology, Xuanwu Hospital of Capital Medical University, Beijing, China.
authors: Aurélien F
authors: AF
authors: Stalder
authors: Zhiyuan
authors: Z
authors: Dong
authors: Qi
authors: Q
authors: Yang
authors: Jelena
authors: J
authors: Bock
authors: Jürgen
authors: J
authors: Hennig
authors: Michael
authors: M
authors: Markl
authors: Kuncheng
authors: K
authors: Li
mesh_terms: D000328:Adult; D000465:Algorithms; D001013:Aorta, Thoracic / Q000473:pathology*; D001783:Blood Flow Velocity; D002319:Cardiovascular System / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D015203:Reproducibility of Results