Background: The clinical application of cardiovascular magnetic resonance (CMR) T 2 and T 2 * mapping is currently limited as ranges for healthy and cardiac diseases are poorly defined. In this meta-analysis we aimed to determine the weighted mean of T 2 and T 2 * mapping values in patients with myocardial infarction (MI), heart transplantation, non-ischemic cardiomyopathies (NICM) and hypertension, and the standardized mean difference (SMD) of each population with healthy controls. Additionally, the variation of mapping outcomes between studies was investigated. Methods: The PRISMA guidelines were followed after literature searches on PubMed and Embase. Studies reporting CMR T 2 or T 2 * values measured in patients were included. The SMD was calculated using a random effects model and a meta-regression analysis was performed for populations with sufficient published data. Results: One hundred fifty-four studies, including 13,804 patient and 4392 control measurements, were included. T 2 values were higher in patients with MI, heart transplantation, sarcoidosis, systemic lupus erythematosus, amyloidosis, hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM) and myocarditis (

CARDIAC IMAGINGC ardiovascular diseases are often associated with a disruption of the oxygen demand and supply equilibrium, which can lead to functional impairments and heart failure (1). There are numerous methods to diagnose myocardial ischemia by using surrogate markers (2), but these techniques often need contrast agents, vasodilators, or radiation, and do not directly reflect the ischemic response (3).Cardiac MRI can be used to assess myocardial oxygenation by using the blood oxygen level-dependent (BOLD) effect (4). Both T2-and T2*-weighted imaging and mapping approaches (5-7) have been used as cardiac BOLD MRI techniques to help identify coronary artery disease without the use of exogenous contrast agent (8-11). Breath-hold interventions are recognized to trigger a cardiac BOLD response (8,(11)(12)(13), causing an increase in vascular CO 2 levels and myocardial vasodilation within 15 seconds ( 14), which results in an increase of myocardial T2 and T2*. In addition to depicting coronary artery disease, it has been hypothesized that cardiac BOLD MRI may be able to depict microvascular dysfunction in conditions such as hypertension (1,15) because of expected differences in vascular response ( 16). Depiction of these relatively subtle differences by using current BOLD MRI techniques is challenging, but several approaches have been developed to

PurposeTo evaluate if a fully-automatic deep learning method for myocardial strain analysis based on magnetic resonance imaging (MRI) cine images can detect asymptomatic dysfunction in young adults with cardiac risk factors.MethodsAn automated workflow termed DeepStrain was implemented using two U-Net models for segmentation and motion tracking. DeepStrain was trained and tested using short-axis cine-MRI images from healthy subjects and patients with cardiac disease. Subsequently, subjects aged 18–45 years were prospectively recruited and classified among age- and gender-matched groups: risk factor group (RFG) 1 including overweight without hypertension or type 2 diabetes; RFG2 including hypertension without type 2 diabetes, regardless of overweight; RFG3 including type 2 diabetes, regardless of overweight or hypertension. Subjects underwent cardiac short-axis cine-MRI image acquisition. Differences in DeepStrain-based left ventricular global circumferential and radial strain and strain rate among groups were evaluated.ResultsThe cohort consisted of 119 participants: 30 controls, 39 in RFG1, 30 in RFG2, and 20 in RFG3. Despite comparable (>0.05) left-ventricular mass, volumes, and ejection fraction, all groups (RFG1, RFG2, RFG3) showed signs of asymptomatic left ventricular diastolic and systolic dysfunction, evidenced by lower circumferential early-diastolic strain rate (<0.05, <0.001, <0.01), and lower septal circumferential end-systolic strain (<0.001, <0.05, <0.001) compared with controls. Multivariate linear regression showed that body surface area correlated negatively with all strain measures (<0.01), and mean arterial pressure correlated negatively with early-diastolic strain rate (<0.01).ConclusionDeepStrain fully-automatically provided evidence of asymptomatic left ventricular diastolic and systolic dysfunction in asymptomatic young adults with overweight, hypertension, and type 2 diabetes risk factors.