Non-contrast-enhanced magnetic resonance angiography is equal to contrast-enhanced multislice computed tomography for correct aortic sizing before transcatheter aortic valve implantation

Correct sizing of the aortic annulus in aortic valve stenosis is crucial for successful transcatheter aortic valve implantation (TAVI). Multislice computed tomography (MSCT) seems to be most promising imaging modality for this pre-interventional diagnostic work-up, but has the disadvantage of exposing mostly co-morbid patients to iodine and nephrotoxic contrast agents. To establish a useful sizing method for TAVI without the use of contrast media, we compared measurements of a non-contrast magnetic resonance imaging (MRI) technique with MSCT serving as the reference standard. Fifty-two patients who underwent TAVI were previously examined with MSCT and MRI, respectively. MRI examination included a 3D steady-state free-precession sequence covering the entire ascending aorta. Perimeter and area of the aortic root were analyzed by two blinded readers in consensus using a dedicated software. Decisions for Sapien 3 valve size of both imaging modalities were compared using the mean derived annulus diameter. Mean age of the study cohort was 82.2 +/- A 4.9 years, log EuroScore was 25.2 +/- A 4.8 %. Mean aortic annulus perimeter as measured by MSCT was 76.7 +/- A 6.9 mm. MRI yielded a mean perimeter of 76.5 +/- A 6.7 mm with a good correlation coefficient (r = 0.93, p < 0.0001). Decision for valve size showed good correlation between both imaging modalities (r = 0.94, p < 0.0001). In conclusion, non-contrast MRI shows good correlation to MSCT in the assessment of the aortic annulus and valve sizing. This non-contrast technique might be a reasonable alternative for aortic root sizing before TAVI without the use of nephrotoxic contrast agents, especially in patients with severely reduced kidney function.