Abstract 12360: Cardiac Magnetic Resonance T1 Mapping for the Assessment of Diffuse Myocardial Fibrosi
Introduction: Myocardial fibrosis is a histological hallmark of heart failure and an independent predictor of adverse outcome. Late gadolinium enhancement (LGE) by cardiac magnetic resonance (CMR) is a standard noninvasive tool for the identification of focal fibrosis. Diffuse fibrosis, however, cannot be quantified by LGE. Recently it was shown that diffuse myocardial fibrosis is strongly related to post-contrast longitudinal relaxation (T1) time. The aim of our study was to assess diffuse myocardial fibrosis by CMR T1 mapping in patients with serum NT-proBNP levels > 125 pg/ml and preserved left ventricular ejection fraction (EF≥50%).
Methods: 37 patients and three healthy controls with normal NT-proBNP were prospectively assessed. CMR studies included the assessment of cardiac function and dimensions by cine sequences. Myocardial T1 mapping was performed 10 minutes after gadolinium bolus using an inversion recovery sequence.
Results: NT-proBNP levels ranged from 131 to 3952 pg/ml (mean 717 ± 899 pg/ml). Areas with LGE indicating local fibrosis in 5 patients were excluded from T1 analysis. Post-contrast T1 was significantly related to NT-proBNP levels (R= -0.67, p<0.0001), EF of left (R=0.36, p=0.022) and right ventricle (R=0.41, p<0.01), and left atrial diameter (R= -0.36, p=0.022). In patients with NT-proBNP levels >400 pg/ml mean T1 was significantly shorter than in patients with NT-proBNP <400 pg/ml (374.6 ± 51.1 vs. 404.6 ± 34.4 ms, p=0.042) and controls (509.4 ± 46.5 ms, p<0.001). Furthermore, T1 was strongly related to degree of diastolic dysfunction by echocardiography (p=0.008) but independent of age, heart rate and renal function.
Conclusion: Post-contrast T1 is highly correlated with NT-proBNP, degree of diastolic dysfunction and cardiac function. Our data suggest that T1 mapping is a promising tool for the assessment of diffuse myocardial fibrosis. Its prognostic impact in heart failure patients remains to be determined.
- © 2011 by American Heart Association, Inc.