Myocardial native T1 mapping and correlations with clinical and CMR parameters in patients with systemic sclerosis
Authors: Meloni A , Gargani L , Bruni C , Cavallaro C , Gobbo M , D"angelo G , Martini N , Grigioni F , Sinagra G , Mavrogeni S , Matucci-Cerinic M , Pepe A 
Published: February 2021

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
Systemic sclerosis (SSc) is a connective tissue disease characterized by diffuse vascular lesions and fibrosis, also affecting the heart. Cardiovascular magnetic resonance (CMR) can detect replacement myocardial fibrosis by late gadolinium enhancement (LGE) and interstitial myocardial fibrosis/edema by T1 mapping techniques.

Purpose
To evaluate the prevalence of cardiac involvement by native T1 mapping and its correlation with clinical and CMR parameters in SSc patients.

Methods
Fifty-one consecutive SSc patients (mean age 51.8 ± 13.7 years, 42 females) and 51 healthy subjects matched for age and sex underwent clinical, bio-humoral assessment, and CMR at 1.5T (Signa Artist, GE Healthcare ). The imaging protocol included: cine, T1 mapping by MOLLI, T2 mapping by multi-echo fast-spin-echo sequence, LGE, and STIR T2-weighted sequences. Native T1 and T2 values were assessed in all 16 myocardial segments and the global value was the mean.
Results. Global native T1 values were significantly higher in SSc patients than in healthy subjects (1076.4 ± 50.7 vs 1033.3 ± 31.9 ms; P &lt; 0.0001).
As in healthy subjects, in patients native T1 values were significantly lower in males than in females (1033.4 ± 38.3 vs 1085.6 ± 48.6 ms; P = 0.004) and inversely correlated with age (R=-0415; P = 0.002).
Twenty-three (45.1%) patients had an increased global heart T1 value (&gt;1060 ms in males and &gt;1085 ms in females). Of them, 14 patients (60.9 %) showed positive LGE. Frequency of cardiovascular risk factors, indices of disease activity and chronicity, biochemical parameters, and cardio-active therapy were comparable between patients with normal and elevated T1. Compared to patients with normal T1 value, patients with elevated T1 had significantly higher left ventricular (LV) end-diastolic volume index (76.8 ± 13.3 vs 69.2 ± 11.8, P = 0.050), LV stroke volume index (49.7 ± 6.4 vs 44.4 ± 6.9 ml/m2; P = 0.010), LV cardiac output (3.6 ± 0.5 vs 3.0 ± 0.6 l/min /m2; P &lt; 0.0001), and global heart T2 values (60.1 ± 3.6 vs 55.7 ± 3.1 ms; P &lt; 0.0001).
Replacement myocardial fibrosis was detected in 24 (47.1%) patients and they showed significantly higher global heart native T1 values (Figure 1A).
Positive T2-weighted images for myocardial oedema were found in 5 (9.8%) patients, all with increased global heart native T1 value. Patients with oedema had significantly higher native global heart T1 values (Figure 1B).

Conclusion
Elevated native T1 values measured by CMR are frequent in SSc patients and they are associated with inflammation, replacement fibrosis, and increased LV dimension. CMR T1 mapping seems to be a sensitive parameter to include in the routine clinical assessment of SSc patients for detecting earlier pejorative cardiac involvement, although prospective data are recommended.
Abstract Figure.