Impact of Sex and Cardiovascular Risk Factors on Myocardial T1, Extracellular Volume Fraction, and T2 at 3 Tesla: Results From the Population-Based, Hamburg City Health Study

Abstract

Background: Reliable reference intervals are crucial for clinical application of myocardial T1 and T2 mapping cardiovascular magnetic resonance imaging. This study evaluated the impact of sex and cardiovascular risk factors on myocardial T1, extracellular volume fraction (ECV), and T2 at 3T in the population-based HCHS (Hamburg City Health Study). Methods: The final study sample consisted of 1576 consecutive HCHS participants between 46 and 78 years without prevalent heart disease, including 1020 (67.3%) participants with hypertension and 110 (7.5%) with diabetes. T1 and T2 mapping were performed on a 3T scanner using 5b(3b)3b modified Look-Locker inversion recovery and T2 prepared, fast-low-angle shot sequence, respectively. Stepwise regression analyses were performed to identify variables with an independent impact on T1, ECV, and T2. Reference intervals were defined as the interval between the 2.5% and 97.5% quantiles. Results: Sex was the major independent influencing factor of myocardial native T1, ECV, and T2. Female patients had significantly higher upper limits of reference intervals for native T1 (1112–1261 versus 1079–1241 ms), ECV (23%–33% versus 22%–32%), and T2 (36–46 versus 35–45 ms) compared with male patients (all P <0.001). Cardiovascular risk factors, such as diabetes and hypertension, did not systematically affect native T1. There was an independent association of T2 by hypertension and, to a lesser degree, by left ventricular mass, heart rate (all P <0.001), and body mass index ( P =0.001). Conclusions: Sex needs to be considered as the major, independent influencing factor for clinical application of myocardial T1, ECV, and T2 measurements. Consequently, sex-specific reference intervals should be used in clinical routine. Our findings suggest that there is no need for specific reference intervals for myocardial T1 and ECV measurements in individuals with cardiovascular risk factors. However, hypertension should be considered as an additional factor for clinical application of T2 measurements. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03934957.

Cardiovascular Magnetic Resonance Tissue Characterization by T1 and T2 Mapping: A Moving Target in Need of Stable References

“…Furthermore, some of the more recent cardiovascular risk scores include inflammatory markers like CRP (C-reactive protein) which increases their prognostic value. Cavus et al 3 do not report any association with inflammatory markers, although myocardial fibrosis quantified by T1 and ECV have been linked to systemic inflammation markers like CRP. 8 In MESA, investigators found native T1 to be slightly elevated in participants treated for diabetes, and ECV was higher in smokers.…”

“…More than 80% of the studies included in the metaanalysis had groups of healthy controls with 50 or fewer subjects, with a median of 20 subjects for studies at 3 Tesla. The study by Cavus et al 3 with 1576 participants all scanned at 3 Tesla, provides, therefore, valuable data for T1 and T2 reference ranges for a much larger cohort.…”

“…4 Establishing reference ranges has in the past been challenging as noted in a recent meta-analysis of native T1 mapping in healthy individuals 5 which concluded that the “relatively high degree of heterogeneity may preclude the derivation of a normal range for native T1.” More than 80% of the studies included in the meta-analysis had groups of healthy controls with 50 or fewer subjects, with a median of 20 subjects for studies at 3 Tesla. The study by Cavus et al 3 with 1576 participants all scanned at 3 Tesla, provides, therefore, valuable data for T1 and T2 reference ranges for a much larger cohort.…”

“…T2 mapping has been somewhat neglected compared to T1 mapping and was not included in the MESA imaging protocol or mentioned in a previously published report about the UK Biobank CMR imaging protocol. 9 The CMR community now has at its disposal good techniques for T2 mapping and Cavus et al 3 provide an encouraging first example in a population-based study of individuals without overt cardiovascular disease. In the HCHS, native T2, but not T1 and ECV, was significantly different between the subgroups with and without cardiovascular risk factors.…”

“…In the current issue of Circulation: Cardiovascular Imaging , Cavus et al 3 report on reference ranges for the native myocardial relaxation times T1 and T2 and on the effects of sex and cardiovascular risk factors on T1 and T2 in 1576 HCHS participants imaged with CMR at 3 Tesla field strength. Native T1 and T2 (ie, the T1 and T2 relaxation times measured without any gadolinium contrast) depend on the magnetic field strength at which a CMR scanner operates, but also on the pulse sequence techniques being used, including their parameter settings.…”