1.5 achieva

CMR was performed on a 1.5 Tesla scanner (Philips 1.5 Achieva or Integra). Standard cine acquisitions included a short-axis stack (30 phases, 7 mm thickness with 3 mm gap) for RV and left ventricle (LV) volume and function. Thereafter, a single mid-ventricle short-axis plane Look-Locker sequence was prescribed 3 cm apically from the atrioventricular valves viewed in 4 chamber view (8 mm thickness, 16 – 21 phases, TR/TE 8/2.5 ms, temporal resolution 40 ms). The Look-Locker method allowed for analysis of each phase to provide better scrutiny of avoiding trabecular pooling and makes no assumptions about interphase registration. Following gadolinium contrast administration (0.15 mmol/kg), the sequence was repeated at 3, 7, and 15 minutes post injection. To allow for full relaxation between inversion pulses, the expected heart rate was set to 20 – 30 bpm on the scanner, and the repetition time for inversion was set to ~4 seconds for pre-contrast T₁ measurements and ~2 seconds post-contrast accounting for shorter T₁ times. The inversion time increments in the Look-Locker read-out were approximately 120 ms for pre-contrast and 90 ms for post-contrast sequences, changed by adjustment of the segmentation factor. Late gadolinium enhancement imaging followed the final Look-Locker acquisition.