Native myocardial T1 and ECV with age and gender developing normal reference ranges - a 94 healthy volunteer study

Background Measurement of native T1 and extracellular volume fraction (ECV) allow quantification of diffuse myocardial fibrosis. Normal references ranges are not definitively established. The concept of increasing fibrosis with age is widely held, despite a lack of supportive evidence from tissue studies some of which say the opposite (Olivetti 1991) or point to other age changes eg myocardial lipofuschin or haemosiderin accumulation. Whether the ECV increases with age is unclear The MESA study found a small ECV increase with age (R 0.021, p = 0.012, Lima JACC 2013) but used measurement rather than mapping, whilst others (Ugander, Schelbert) found increases but with small populations or with significant comorbidities. Using state-of-the-art mapping, we sought to determine whether T1 and ECV increase with age both to understand the aging biology and as a step towards developing normal reference ranges.

Native myocardial T1 and ECV with age and gender developing normal reference rangesa 94 healthy volunteer study Stefania Rosmini 1* , Heerajnarain Bulluck 1 , Thomas A Treibel 1 , Amna Abdel-Gadir 1 , Anish N Bhuva 1 , Veronica Culotta 1 , Ahmed Merghani 2 , Viviana Maestrini 3 , Anna S Herrey 1 , Peter Kellman 4 , Charlotte Manisty 1 , James Moon 1 From 19th Annual SCMR Scientific Sessions Los Angeles, CA, USA. 27-30 January 2016 Background Measurement of native T1 and extracellular volume fraction (ECV) allow quantification of diffuse myocardial fibrosis. Normal references ranges are not definitively established. The concept of increasing fibrosis with age is widely held, despite a lack of supportive evidence from tissue studies -some of which say the opposite (Olivetti 1991) or point to other age changes eg myocardial lipofuschin or haemosiderin accumulation.
Whether the ECV increases with age is unclear -The MESA study found a small ECV increase with age (R 2 0.021, p = 0.012, Lima JACC 2013) but used measurement rather than mapping, whilst others (Ugander, Schelbert) found increases but with small populations or with significant comorbidities. Using state-of-the-art mapping, we sought to determine whether T1 and ECV increase with age -both to understand the aging biology and as a step towards developing normal reference ranges.
Manual epi-and endocardial contours were drawn using CVI42 (Calgary, Canada). Every effort was made to avoid confounders, with blood partial voluming being a particular concern. We therefore initially assessed the effect of different degrees of endo-and epicardial border erosion and showed that using values >10% conferred no added value, therefore 10% was used for all studies.

Results
Mean age was 50 ± 14, range 20-76 years, male 52%, with no gender difference in age ( Figure 1B). Heart rate decreased slightly with age (R 2 0.075, coeff. -0.273, p = 0.008) but there was no relationship between age and other influences on blood T1 (hematocrit, iron and HDL cholesterol).
Overall mean myocardial T1 and ECV were 1025 ± 38 ms and 27.4 ± 2.8 by MOLLI and 957 ± 30 ms and 28.4 ± 3 ms by ShMOLLI, with higher values in females than males for both ( Figure 1B) Native myocardial T1 reduced slightly with age (R 2 0.131, p < 0.0001 by MOLLI, Figure 2A, and R 2 0.042, p 0.048 by ShMOLLI) -on average by 11 ms/decade by MOLLI and 8 ms/decade by ShMOLLI.