Abstract
Introduction: For successful transcatheter aortic valve implantation (TAVI) correct sizing of the aortic annulus and left ventricular outflow tract in aortic valve stenosis is crucial. With multislice computed tomography (MSCT) 3D volume data sets of the aorta could be acquired in high spatial resolution, but the comorbid patients are exposed to nephrotoxic contrast agents leading to kidney injury in many cases. Hypothesis: The purpose of this study was to establish a useful method for sizing for TAVI without the use of contrast media. With MSCT serving as a the reference standard, we compared measurements of a non-contrast 3D steady-state free-precession (SSFP) magnetic resonance (MRI) for correct annulus sizing and decision for valve size. Methods: We examined 52 patients previous to TAVI with MSCT using a 256-MSCT and a 1.5 Tesla whole-body MRI scanner, respectively. MRI examination included a 3D SSFP sequence covering the entire ascending aorta. The 3D images of both imaging modalities were reconstructed for correct orthogonal view of the aortic annulus using a dedicated software (3mensio, Pie Medical Imaging, The Netherlands). Minimal and maximal annulus diameters, annulus perimeters, and areas of both imaging modalities were analyzed by two blinded and experienced readers in consensus. Virtual decision for valve size (Edwards Sapien 3) was based on the median of these diameters. Results: Mean age of the study cohort was 82.2±4.9 years, 32 (61.5%) were female. Log EuroScore was 25.2±4.8%. Mean annulus perimeter measured by MSCT was 76.7±6.9 mm, by MRI 76.5±6.7 mm (r=0.93, p<0.0001). MSCT yielded a mean annulus area of 545.2±49.0 mm2 with good correlation to MRI, which resulted in a mean area of 543.5±47.0 mm2 (r=0.92, p<0.0001). Decision for Sapien 3 valve size showed good correlation between MSCT and MRI (r=0.94, p<0.0001). Conclusions: In conclusion, non-contrast 3D SSFP MRI shows good correlation to MSCT in the assessment of the aortic annulus and valve sizing for TAVI. The non-contrast MRI approach might be a reasonable alternative for aortic root sizing before TAVI without the use of nephrotoxic contrast agents, especially in patients with reduced kidney function.
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