PURPOSE: To evaluate the performance of four-dimensional (4D) flow-sensitive MRI in the thoracic aorta using 12- and 32-channel coils and parallel imaging. MATERIALS AND 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. CONCLUSION: 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.
PURPOSE: To evaluate the performance of four-dimensional (4D) flow-sensitive MRI in the thoracic aorta using 12- and 32-channel coils and parallel imaging. MATERIALS AND 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. CONCLUSION: 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: Marcus R Makowski; Andrea J Wiethoff; Hans U Ebersberger; René M Botnar; Reza Razavi; Tobias Schaeffter; Gerald F Greil Journal: Int J Cardiovasc Imaging Date: 2014-11-11 Impact factor: 2.357
Authors: Tao Zhang; Thomas Grafendorfer; Joseph Y Cheng; Peigang Ning; Bob Rainey; Mark Giancola; Sarah Ortman; Fraser J Robb; Paul D Calderon; Brian A Hargreaves; Michael Lustig; Greig C Scott; John M Pauly; Shreyas S Vasanawala Journal: Magn Reson Med Date: 2015-09-29 Impact factor: 4.668