Native T₁ reference values for nonischemic cardiomyopathies and populations with increased cardiovascular risk: A systematic review and meta‐analysis

Abstract

BackgroundAlthough cardiac MR and T1 mapping are increasingly used to diagnose diffuse fibrosis based cardiac diseases, studies reporting T1 values in healthy and diseased myocardium, particular in nonischemic cardiomyopathies (NICM) and populations with increased cardiovascular risk, seem contradictory.PurposeTo determine the range of native myocardial T1 value ranges in patients with NICM and populations with increased cardiovascular risk.Study TypeSystemic review and meta‐analysis.PopulationPatients with NICM, including hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM), and patients with myocarditis (MC), iron overload, amyloidosis, Fabry disease, and populations with hypertension (HT), diabetes mellitus (DM), and obesity.Field Strength/Sequence(Shortened) modified Look–Locker inversion‐recovery MR sequence at 1.5 or 3T.AssessmentPubMed and Embase were searched following the PRISMA guidelines.Statistical TestsThe summary of standard mean difference (SMD) between the diseased and a healthy control populations was generated using a random‐effects model in combination with meta‐regression analysis.ResultsThe SMD for HCM, DCM, and MC patients were significantly increased (1.41, 1.48, and 1.96, respectively, P < 0.01) compared with healthy controls. The SMD for HT patients with and without left‐ventricle hypertrophy (LVH) together was significantly increased (0.19, P = 0.04), while for HT patients without LVH the SMD was zero (0.03, P = 0.52). The number of studies on amyloidosis, iron overload, Fabry disease, and HT patients with LVH did not meet the requirement to perform a meta‐analysis. However, most studies reported a significantly increased T1 for amyloidosis and HT patients with LVH and a significant decreased T1 for iron overload and Fabry disease patients.Data ConclusionsNative T1 mapping by using an (Sh)MOLLI sequence can potentially assess myocardial changes in HCM, DCM, MC, iron overload, amyloidosis, and Fabry disease compared to controls. In addition, it can help to diagnose left‐ventricular remodeling in HT patients. Level of Evidence: 2 Technical Efficacy: Stage 3J. Magn. Reson. Imaging 2018;47:891–912.

Cardiovascular magnetic resonance native T2 and T2* quantitative values for cardiomyopathies and heart transplantations: a systematic review and meta-analysis

“…Based on these limited available studies no conclusion can be drawn on the clinical relevance of T 2 and T 2 * mapping. More research could enable to determine the clinical applicability of these mapping techniques, while T 1 mapping has already shown to be promising in distinguishing hypertension related LVH and HCM [21,206]. Furthermore, as the incidence of cardiomyopathies is related to obesity and T2DM [8] it is important to determine whether these high cardiovascular risk factors cause myocardial tissue adaptation and if these are distinguishable with quantitative techniques.…”

“…In line with this, the European Society of Cardiology recently described a shifting standards from the assessment of LGE towards the use of T 1 and T 2 mapping in their latest position statement [20]. The clinical utility of T 1 mapping has already been acknowledged and included in some guidelines [8,13,21,22]. In addition, other guidelines also advocate to include T 2 and T 2 * mapping instead of T 2 -weighted imaging [20,[22][23][24].…”

Tissue characterisation and myocardial mechanics using cardiac MRI in children with hypertrophic cardiomyopathy

“…However, native T1 mapping detects abnormalities of both the extracellular matrix and the myocytes, while partition coefficient and synthetic extracellular volume are more specific for extracellular matrix expansion. 22 We hypothesise that the increased native T1 times are primarily reflecting underlying structural abnormalities in the myocytes, not the extracellular matrix. Indeed, a study by Swaboda et al used multivariable modelling in adult hypertrophic cardiomyopathy patients to demonstrate a correlation between native T1 and myocardial mechanics but not extracellular volume fraction, suggesting that the structural abnormalities resulting in impaired function were cellular.…”

“…Indeed, a study by Swaboda et al used multivariable modelling in adult hypertrophic cardiomyopathy patients to demonstrate a correlation between native T1 and myocardial mechanics but not extracellular volume fraction, suggesting that the structural abnormalities resulting in impaired function were cellular. 22 Previous studies in adult hypertrophic cardiomyopathy have demonstrated a statistically significant difference in native T1 between hypertrophic cardiomyopathy and controls. 23 Indeed, some reports have suggested that native T1 can be used to distinguish between patients with and without hypertrophic cardiomyopathy.…”

Kidney transplantation is associated with reduced myocardial fibrosis. A cardiovascular magnetic resonance study with native T1 mapping

“…The native T1 strong correlates with histological myocardial fibrosis in patients with aortic stenosis [21]. In 2018, a meta-analysis established the reference values of native T1 for nonischemic cardiomyopathies and populations with increased cardiovascular risk [22]. Different types of tissue will have their own normal ranges of values, and a significant departure from the normal range is thought to differentiate between normal and abnormal myocardium.…”