1.5t cmr scanner

CMR was performed on a Philips 1.5T CMR scanner (Achieva, Phillips Healthcare, Best, The Netherlands). Prior to contrast injection, ECG-triggered navigator-gated, fat-saturated, T2W 2D black blood fast spin echo imaging was performed in a stack of axial images covering the LA. Image parameters included: 300 mm FOV, 192×192 matrix (1.5×1.5 mm² zero-filled to 0.6×0.6 in-plane resolution), 5 mm slice thickness, 33 echo train length, echo spacing 5.4 ms, 90° flip, TE = 60 ms, 1 average, 15 slices with no gaps, imaging in diastole. Coil-sensitivity correction was used on the T2W images. LGE imaging was performed ∼20 minutes after the injection of 0.2 mmol/kg Gd-DTPA (N = 6; Magnevist, Bayer Healthcare, Leverkusen, Germany; or 0.2 mmol/kg Gd-BOPTA (N = 1; MultiHance; Bracco, Princeton, NJ). The LGE sequence was an ECG-triggered navigator-gated 3D inversion recovery gradient echo sequence with fat saturation. Imaging parameters included: 320 mm FOV, 224×224 matrix, 4 mm slice thickness (spatial resolution 1.4×1.4×4 mm zero-filled to 0.6×0.6×2 mm³), TR/TE/θ = 5.3 ms/2.1 ms/25°, centric acquisition, with 100–150 ms acquisition window in diastole. The inversion time was set to null LV myocardium, using a Look-Locker sequence [32] .

All subjects were planned for CMR at rest in supine position and during end-expiratory breath hold. A 1.5 T CMR scanner was used for all studies (Philips Achieva, Best, The Netherlands). Steady state free precession cine CMR images were acquired in three long-axis planes and in short-axis stacks covering the whole heart. Imaging parameters for cine CMR were typically: retrospective ECG triggering with acquired temporal resolution of 47 ms reconstructed to 30 time phases per cardiac cycle, repetition time 3 ms, echo time 1.4 ms, flip angle 60°, slice thickness of 8 mm with no slice gap. Breath-holds were typically 10 s. Flow velocity mapping was acquired using a retrospectively ECG triggered fast-field echo velocity encoded sequence, acquired as separate acquisitions in the ascending aorta and the pulmonary trunk during free breathing. Imaging parameters were typically: repetition time 10 ms, echo time 5 ms, flip angle 15°, and slice thickness 8 mm, acquired in-plane resolution 2.4 × 2.4 mm reconstructed to 1.3 × 1.3 mm, number of acquisitions 1, no parallel imaging and a velocity encoding gradient (VENC) of 200 cm/s. The flow sequence had an acquired temporal resolution of 20 ms during the cardiac cycle reconstructed to 35 phases per heart cycle and a typical scan time of 2 min.