Aortic annular dimensions by non-contrast MRI using k–t accelerated 3D cine b-SSFP in pre-procedural assessment for transcatheter aortic valve implantation: a technical feasibility study

To evaluate k–t accelerated 3D cine b-SSFP (balanced steady state free precession) as magnetic resonance imaging (MRI) technique for aortic annular area measurement in transcatheter aortic valve replacement (TAVR) planning compared to computed tomography angiography (CTA) and other non-contrast MRI sequences with reduced imaging time and without contrast administration. 6 volunteers and 7 TAVR candidates were prospectively enrolled. The volunteers underwent an MRI while TAVR candidates underwent an MRI and CTA. The following non-contrast MRI sequences were obtained at the level of the aortic root: 2D cine b-SSFP [GRAPPA (GeneRalized Autocalibrating Partially Parallel Acquisitions), R = 2], 3D cine b-SSFP [GRAPPA R = 2], navigator triggered 3D b-SSFP MRA [GRAPPA, R = 2] and k–t accelerated 3D cine b-SSFP [PEAK GRAPPA, R = 5]. Qualitative analysis and aortic annular area measurements in systole and diastole were obtained. k–t accelerated 3D cine b-SSFP provided image quality that is acceptable for confident diagnosis with very good interrater agreement. There was no statistically significant difference in aortic annular measurements between k–t accelerated 3D cine b-SSFP and CTA or other MRI sequences (p > 0.05). Bland–Altman analysis showed no systemic difference of annular area measurements between k–t accelerated 3D cine b-SSFP and each of the other techniques. There was excellent inter-rater agreement on aortic annular area measurements during systolic (ICC = 0.976, p < 0.001) and diastolic (ICC = 0.971, p < 0.001) phases using k–t accelerated 3D cine b-SSFP. K–t accelerated 3D cine b-SSFP is a promising alternative for the assessment of annular sizing in pre-TAVR evaluation while offering a reasonable combination of imaging parameters during one breath-hold.