title: Pre-procedural assessment of aortic annulus dimensions for transcatheter aortic valve replacement: comparison of a non-contrast 3D MRA protocol with contrast-enhanced cardiac dual-source CT angiography.
abstract: OBJECTIVE
  To evaluate the feasibility of a non-contrast three-dimensional (3D)-FLASH magnetic resonance angiography (MRA) protocol for pre-procedural aortic annulus assessment for transcatheter aortic valve replacement (TAVR) in comparison with cardiac dual-source computed tomography angiography (CTA).
  
  
  RESULTS
  In this prospective study, 69 of 104 consecutive patients (mean age 81.8 ± 5.4 years, 37.7% arrhythmic) with severe aortic stenosis who had undergone pre-TAVR cardiac CTA received a respiratory and ECG-triggered, non-contrast 3D-FLASH MRA at 3 T. Annular area measurements were obtained at mid-diastole for both modalities whereas maximum systolic area was assessed by CTA only. Systolic MRA dimensions were modelled, by adding the relative difference of systolic and diastolic CTA area dimensions as a corrective factor. Hypothetical prosthesis sizing was performed based on systolic CTA, diastolic, and modelled systolic MRA area measurements. MR image quality and degree of annular calcifications were evaluated using 4-point-grading scales. The mean acquisition time was 14 ± 4.2 min. The mean image quality was 3.1 ± 0.9 with only two examinations rated non-diagnostic. The mean degree of calcifications was equal. As assessed by Bland-Altman analysis, there was no relevant systematic difference between area measurements for modelled systolic MRA and systolic CTA [the mean difference -3.1 mm(2) (limits of agreement -44.4 mm(2); 38.2 mm(2))]. Agreement for hypothetical prosthesis sizing was found in 63 of 67 (94%) patients for systolic CTA and modelled systolic MRA.
  
  
  CONCLUSIONS
  The employed non-contrast 3D-FLASH MRA protocol allows for reliable assessment of aortic annulus dimensions and calcifications even in the presence of arrhythmias in an all-comers pre-TAVR population. Implementation of this technique appears legitimate in patients at an increased risk for contrast-induced nephropathy.
authors.affiliation: Department of Cardiology & Angiology II, University Heart Center Freiburg-Bad Krozingen, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Ruile
authors.affiliation: Center for Heart Valve Innovations, University of British Columbia, St Pauls Hospital, Vancouver, Canada.
authors.forename: Philipp
authors.initials: P
authors.lastname: Blanke
authors.affiliation: Department of Radiology, Section of Cardiovascular Radiology, University of Freiburg, Südring 15, Bad Krozingen 79189, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Krauss
authors.affiliation: Department of Cardiology & Angiology II, University Heart Center Freiburg-Bad Krozingen, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Dorfs
authors.affiliation: Institute of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Switzerland.
authors.forename: Bernd
authors.initials: B
authors.lastname: Jung
authors.affiliation: Department of Cardiology & Angiology II, University Heart Center Freiburg-Bad Krozingen, Germany.
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Jander
authors.affiliation: Center for Heart Valve Innovations, University of British Columbia, St Pauls Hospital, Vancouver, Canada.
authors.forename: Jonathon
authors.initials: J
authors.lastname: Leipsic
authors.affiliation: Department of Radiology, Section of Cardiovascular Radiology, University of Freiburg, Südring 15, Bad Krozingen 79189, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Langer
authors.affiliation: Department of Cardiology & Angiology II, University Heart Center Freiburg-Bad Krozingen, Germany.
authors.forename: Franz-Josef
authors.initials: FJ
authors.lastname: Neumann
authors.affiliation: Department of Radiology, Section of Cardiovascular Radiology, University of Freiburg, Südring 15, Bad Krozingen 79189, Germany gregor.pache@universitaets-herzzentrum.de.
authors.forename: Gregor
authors.initials: G
authors.lastname: Pache
mesh_terms: D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000601:surgery; D055424:Cardiac-Gated Imaging Techniques; D000072226:Computed Tomography Angiography; D003287:Contrast Media; D003971:Diastole; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007479:Iopamidol / Q000031:analogs & derivatives; D018810:Magnetic Resonance Angiography; D008297:Male; D011300:Preoperative Care; D011446:Prospective Studies; D013599:Systole; D065467:Transcatheter Aortic Valve Replacement
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol
keywords: TAVI; TAVR; computed tomography; magnetic resonance angiography; transcatheter aortic valve replacement