Achieva r 3

MRI was done with a whole‐body 1.5 Tesla MR scanner Achieva R 3.2.2.0 using a five‐element cardiac phased‐array coil (Philips Medical System, Best, Netherlands). Anatomy of the aorta was acquired by a navigator‐triggered 3D WH MRI sequence in end diastole. The sequence parameters were: field of view (FOV) 212 × 212 × 121 mm, matrix size 320 × 320, 76 slices, acquired voxel 0.66 × 0.66 × 3.2 mm, reconstructed voxel 0.66 × 0.66 × 1.6 mm, repetition time (TR) 4.0 ms, echo time (TE) 2.0 ms, flip angle (FA) 90 °, and number of signal averages 3. The scan time was ∼8 min.
The 4D flow MRI of thorax was performed using an anisotropic 4D segmented k‐space phase contrast gradient echo sequence with retrospective electrocardiographic gating but without navigator gating of respiratory motion to minimize acquisition time. The sequence parameters were: FOV 180 × 216 × 75 mm, matrix size 100 × 128, 30 slices, acquired voxel 2.5 × 2.5 × 2.5 mm, reconstructed voxel 1.7 × 1.7 × 2.5 mm, TR 3.5 ms, TE 2.2 ms, FA 5 °, 25 reconstructed cardiac phases, velocity encoding 4.0 m/s, and number of signal averages 1. Scan time varied between 9 and 14 min, depending on the size of the patient's chest. The high velocity encoding in all three directions was used to avoid phase wraps in the presence of stenosis forming complex 3D flow.