Detection of acute myocarditis using T1 and T2 mapping cardiovascular magnetic resonance: A systematic review and meta‐analysis

Cho

et al. 2022

Sci Rep

To evaluate variations in pre-contrast (preT1) and post-contrast (postT1) myocardial T1 values and extracellular volume fraction (ECV) according to left ventricular (LV) segments and to find correlations between them and cardiovascular risk factors. The 233 asymptomatic subjects (210 men, 23 women; aged 54.1 ± 6.0 years) underwent cardiac magnetic resonance imaging with preT1 and postT1 mapping on a 1.5-T scanner. T1 values and ECVs were evaluated according to LV segments, age, sex, and estimated glomerular filtration rate (eGFR). Based on the presence of hypertension (HTN) and diabetes mellitus (DM), subjects were subdivided into the control, HTN, DM, and HTN and DM (HTN-DM) groups. T1 values and ECV showed significant differences between septal and lateral segments at the mid-ventricular and basal levels (p ≤ 0.003). In subgroup analysis, the HTN-DM group showed a significantly higher ECV (0.260 ± 0.023) than the control (0.240 ± 0.021, p = 0.011) and HTN (0.241 ± 0.024, p = 0.041) groups. Overall postT1 and ECV of the LV had significant correlation with eGFR (r = 0.19, p = 0.038 for postT1; r = − 0.23, p = 0.011 for ECV). Septal segments show higher preT1 and ECV but lower postT1 than lateral segments at the mid-ventricular and basal levels. ECV is significantly affected by HTN, DM, and eGFR, even in asymptomatic subjects.

Section: Discussionmentioning

confidence: 99%

T1 values and extracellular volume fraction in asymptomatic subjects: variations in left ventricular segments and correlation with cardiovascular risk factors

Cho

et al. 2022

Sci Rep

“…T1 and T2 CMR mapping of increased extracellular volume offers a comparably high diagnostic level for detection and accurate quantification of edema and fibrosis, seen in different stages of acute myocarditis. However, pathologies with similar presentation, previous myocardial damage or presence of chronic myocarditis can cause misdiagnosing with isolated use of CMR, as specificity reportedly declines in patients with a subsequent EMB performed [ 8 , 9 , 10 , 11 ]. Still, there is a good correlation between CMR and EMB findings, with up to 78% overall accuracy when updated Lake Louise criteria are applied [ 4 , 12 , 13 ].…”

Section: Resultsmentioning

confidence: 99%

Role of Endomyocardial Biopsy in Diagnostics of Myocarditis

et al. 2022

Endomyocardial biopsy as the cornerstone of diagnostics has been re-evaluated throughout the years, leaving unanswered questions on the precedence of it. The reported incidence of myocarditis has increased during the pandemic of coronavirus disease 2019 (COVID-19), reinforcing discussions on appropriate diagnostics of myocarditis. By analysis of evidence-based literature published within the last demi-decade, we aimed to summarize the most recent information in order to evaluate the current role of endomyocardial biopsy in diagnostics and management of myocarditis. For the most part, research published over the last five years showed ongoing uncertainty regarding the use, informativeness, safety and necessity of performing a biopsy. Special circumstances, such as fulminant clinical course or failure to respond to empirical treatment, were reconfirmed as justified indications, with a growing applicability of non-invasive diagnostic approaches for most other cases. We concluded that endomyocardial biopsy, if performed properly and with adjunct diagnostic methods, holds a critical role for treatment correction in specific histological subtypes of myocarditis and for differential diagnosis between immune-mediated myocarditis and secondary infections due to immunosuppressive treatment. A high level of possible misdiagnosing was detected, indicating the need to review terminology used to describe findings of myocardial inflammation that did not meet Dallas criteria.

“…In myocarditis, T1 mapping demonstrated highest sensitivity for cardiac injury while edema-sensitive T2 mapping can be used to differentiate acute from healing myocarditis. 29 After MI, T1/T2 mapping or late gadolinium enhancement (LGE) are used for quanti cation of the ischemic scar and the area at risk. 30 In our model we allowed for reperfusion after 40 minutes of MI.…”

Section: Discussionmentioning

confidence: 99%

Interventional real-time molecular MRI allows diagnostic targeting of early myocardial injury in a pig model of ischemia and reperfusion

Heidt,

Reiss,

Thielmann

et al. 2024

Preprint

Introduction: Inflammation is a hallmark of post-ischemic myocardial injury. Expression of P-selectin by platelets and activated endothelial cells drives recruitment of immune cells to the deprived area and may serve as an early indicator of tissue injury. Due to its high soft tissue contrast, magnetic resonance imaging (MRI) is used for myocardial tissue characterization. Molecular imaging further allows for functional assessment using target-specific contrast agents. In this study, we assessed ischemic cardiac lesions non-invasively within the first hours after ischemia/reperfusion (I/R) in a porcine model using standard and advanced MRI techniques as well as molecular imaging targeting the cell adhesion molecule P-selectin. Methods: For molecular imaging, a monoclonal P-selectin antibody was functionalized with microparticles of iron oxide (MPIO). Specific binding to the target was confirmed by in vitro flow chamber using activated platelets as well as endothelial cells. In vivo, we used a closed-chest model of I/R of the circumflex artery in juvenile farm pigs by balloon-occlusion for 40 minutes, and real time MRI-guided coronary injection of MPIO-based contrast agents. 3T MRI was performed 2–4 hours after reperfusion, and lesions were characterized using injury (T1 mapping, LGE), edema (T2 mapping) and iron (T2* mapping) sensitive MRI. Results: Within the first hours after I/R, we detected increased inflammatory activity by means of higher numbers of innate immune cells in the blood. We found T1 mapping to be most sensitive for tissue injury, while no changes were detectable in edema-sensitive T2 mapping this early. Intriguingly, P-selectin MPIO contrast agent selectively enhanced the ischemic area in iron sensitive T2* mapping 4 hours after I/R which was confirmed histologically, while late gadolinium enhancement was always absent. Conclusion: By using real time MRI-guided coronary intervention, molecular MRI using P-selectin MPIO allows for sensitive detection of early myocardial inflammation after I/R beyond the capabilities of traditional edema sensitive imaging.