Longitudinal changes in myocardial T1 and T2 relaxation times related to diffuse myocardial fibrosis in aortic stenosis; before and after aortic valve replacement

Sofia Kvernby; Mattias Rönnerfalk; Marcel Warntjes; Carl-Johan Carlhäll; Eva Nylander; Jan Engvall; Éva Tamás; Tino Ebbers

doi:10.1002/jmri.25980

Longitudinal changes in myocardial T₁ and T₂ relaxation times related to diffuse myocardial fibrosis in aortic stenosis; before and after aortic valve replacement

J Magn Reson Imaging. 2018 Feb 23. doi: 10.1002/jmri.25980. Online ahead of print.

Authors

Sofia Kvernby^{1

2}, Mattias Rönnerfalk³, Marcel Warntjes^{2

4

5}, Carl-Johan Carlhäll^{2

6}, Eva Nylander⁶, Jan Engvall^{2

6}, Éva Tamás^{2

3}, Tino Ebbers^{2

4}

Affiliations

¹ Department of Radiation Physics and Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
² Center for Medical Image Science and Visualization (CMIV), Linköping University, Sweden.
³ Department of Cardiothoracic and Vascular Surgery and Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
⁴ Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
⁵ SyntheticMR AB, Linköping, Sweden.
⁶ Department of Clinical Physiology and Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.

PMID: 29473982
DOI: 10.1002/jmri.25980

Abstract

Background: Diffuse myocardial fibrosis is associated with adverse outcomes, although detection and quantification is challenging. Cardiac MR relaxation times mapping represents a promising imaging biomarker for diffuse myocardial fibrosis.

Purpose: To investigate whether relaxation times can detect longitudinal changes in myocardial tissue composition associated with diffuse fibrosis in patients with severe aortic stenosis (AS) before and after aortic valve replacement (AVR).

Study type: Prospective longitudinal study.

Population/subjects/phantom/specimen/animal model: Fifteen patients with severe AS.

Field strength/sequence: 3T / 3(3)3(3)5-MOLLI, T₂ -GraSE, and 3D-QALAS.

Assessment: Patients underwent MR examinations at three timepoints: before AVR, as well as 3 and 12 months after AVR. Data from each patient was analyzed in 16 myocardial segments.

Statistical tests: The segment-wise T₁ and T₂ data were analyzed over time after surgery using linear mixed models for repeated measures analysis.

Results: The results showed that T₁ relaxation times were significantly (P < 0.05) shorter 3 and 12 months postoperative than preoperative and that the T₂ relaxation times were significantly (P < 0.05) longer 3 and 12 months postoperative than preoperative for both 3D and 2D mapping methods. No significant changes were seen between 3 and 12 months postoperative for any of the methods (P = 0.06/0.19 for T₁ with 3D-QALAS/MOLLI and P = 0.09/0.25 for T₂ with 3D-QALAS/GraSE).

Data conclusion: We demonstrated that changes in myocardial relaxation times and thus tissue characteristics can be observed within 3 months after AVR surgery. The significant changes in relaxation times from preoperative examinations to the follow-up may be interpreted as a reduction of interstitial fibrosis in the left ventricular wall.

Level of evidence: 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018.

Keywords: aortic stenosis; aortic valve replacement; fibrosis; longitudinal study; relaxation times mapping; remodeling.