CMR T1 reactivity in healthy adult hearts: A Systematic Review and Meta-Analysis

Bingquan Wang¹Xiaoyi Deng^1*Hongyu Gu¹LingLing Kong¹Luo Song²

• ¹Aoyang Hospital Affiliated to Jiangsu University, Jiangsu, China
• ²Geriatric Hospital of Nanjing Medical University, Jiangsu, China

Abstract: Background: Cardiac stress T1-mapping is an advanced magnetic resonance imaging technique that enables the detection of myocardial ischemia and coronary microvascular dysfunction without the need for gadolinium-based contrast agents (GBCAs). This review seeks to synthesize reported mean ΔT1 values from studies involving healthy adults, establish an approximate range of myocardial T1 reactivity in this population, and explore factors underlying the heterogeneity observed across different studies. Methods: PubMed, Web of Science, and Cochrane Central were searched for studies reporting myocardial T1 reactivity in healthy adult participants. The search strategy included terms such as: "Stress T1 'AND' Mapping" OR "Stress T1 'AND' Cardiovascular magnetic resonance" OR "Stress T1 'AND' CMR" OR "T1 reactivity 'AND' Cardiovascular magnetic resonance" OR "T1 reactivity 'AND' CMR." Use the Joanna Briggs Institute (JBI) quantitative critical appraisal tools for documentation quality assessment. The average value is summarized using the random effect model, and heterogeneity was assessed by using the inconsistency factor (I2). A sensitivity analysis of the incorporated research was carried out using a one-by-one exclusion method. Subgroup analysis and regression analysis were used to determine the causes of heterogeneity. Results: This systematic review of T1 reactivity included 10 articles (11 study groups), with 226 participants (mean age, 52.21 years; 56.19% men [127 of 226] ). The pooled mean of ΔT1 was 6.22%(95% confidence interval [CI] : 5.60,6.84). I2 was 89.07%. The mean ΔT1 was 5.42%(95% CI:4.77, 6.07) at modified Look Locker Inversion recovery (MOLLI) and 6.82% (95% CI:5.98,7.66) at shortened modified Look Locker inversion recovery (SHMOLLI). There was substantial heterogeneity in both pools (I2= 80.16% and I2= 83.89% at MOLLI and SHMOLLI, respectively). There is a statistically significant statistical difference in ΔT1 between MOLLI and SHMOLLI (p = 0.01). Pooled meta-regression analyses of all health study cohorts revealed age as an significantly associated with ΔT1 value variations (p=0.038). Conclusions: This analysis summarizes the pooled means and CI of T1 reactivity in healthy CMR T1 reactivity in healthy adult hearts: A Systematic Review and Meta-Analysis adult participants. Significant heterogeneity was observed, highlighting the need to standardize cardiac MRI protocols and to investigate factors influencing T1 reactivity.