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Heart 99:932-937 doi:10.1136/heartjnl-2012-303052
  • Cardiovascular imaging
  • Original article

Human non-contrast T1 values and correlation with histology in diffuse fibrosis

Open Access
  1. Saul G Myerson1
  1. 1Department of Cardiovascular Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, UK
  2. 2Heart Hospital Imaging Centre, Institute of Cardiovascular Science, University College London, London, UK
  3. 3Oxford Heart Centre, John Radcliffe Hospital, Oxford, UK
  1. Correspondence to Dr Saul G Myerson, Department of Cardiovascular Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, Level 0, Headley Way, Oxford OX3 9DU, UK; saul.myerson{at}cardiov.ox.ac.uk
  • Received 1 October 2012
  • Revised 27 November 2012
  • Accepted 11 December 2012
  • Published Online First 24 January 2013

Abstract

Background Aortic stenosis (AS) leads to diffuse fibrosis in the myocardium, which is linked to adverse outcome. Myocardial T1 values change with tissue composition.

Objective To test the hypothesis that our recently developed non-contrast cardiac magnetic resonance (CMR) T1 mapping sequence could identify myocardial fibrosis without contrast agent.

Design, setting and patients A prospective CMR non-contrast T1 mapping study of 109 patients with moderate and severe AS and 33 age- and gender-matched controls.

Methods CMR at 1.5 T, including non-contrast T1 mapping using a shortened modified Look–Locker inversion recovery sequence, was carried out. Biopsy samples for histological assessment of collagen volume fraction (CVF%) were obtained in 19 patients undergoing aortic valve replacement.

Results There was a significant correlation between T1 values and CVF% (r=0.65, p=0.002). Mean T1 values were significantly longer in all groups with severe AS (972±33 ms in severe asymptomatic, 1014±38 ms in severe symptomatic) than in normal controls (944±16 ms) (p<0.05). The strongest associations with T1 values were for aortic valve area (r=−0.40, p=0.001) and left ventricular mass index (LVMI) (r=0.36, p=0.008), and these were the only independent predictors on multivariate analysis.

Conclusions Non-contrast T1 values are increased in patients with severe AS and further increase in symptomatic compared with asymptomatic patients. T1 values lengthened with greater LVMI and correlated with the degree of biopsy-quantified fibrosis. This may provide a useful clinical assessment of diffuse myocardial fibrosis in the future.

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