Detection and Monitoring of Acute Myocarditis Applying Quantitative Cardiovascular Magnetic Resonance

Abstract

Background— Cardiovascular magnetic resonance based on the Lake Louise Criteria is used to make the diagnosis of acute myocarditis. Novel quantitative parametric mapping techniques promise to overcome some of its limitations. We aimed to evaluate quantitative cardiovascular magnetic resonance to detect and monitor acute myocarditis. Methods and Results— Eighteen patients with clinical diagnosis of acute myocarditis (25 years [23–38 years]; 78% males) were prospectively enrolled and repeatedly underwent cardiovascular magnetic resonance at 1.5 T seven days (5–10 days) after symptom onset (FU0), after 5 weeks (FU1), and after 6 months (FU2). Eighteen age- and sex-matched healthy subjects served as controls. Cardiovascular magnetic resonance included imaging of edema, hyperemia, necrosis, and fibrosis using semiquantitative T2-weighted spin echo, T2 mapping, and T1 mapping before and 3 and 10 minutes after gadobutrol administration. Extracellular volume for diffuse and late gadolinium enhancement for focal fibrosis were assessed. Compared with controls, patients had significantly higher global T2 times at FU0 (55.1 ms [53.3–57.2 ms] versus 50.2 ms [49.2–52.0 ms]; P <0.001) and at FU1 (52.0 ms [52.0–53.2 ms]; P =0.007), which normalized at FU2 (50.9 ms [49.6–53.3 ms]; P =0.323). Global native T1 times in patients were elevated acutely (1004 ms [988–1048 ms] versus 975 ms [957–1004 ms]; P =0.002) and remained elevated throughout the follow-up (FU1: 998 ms [990–1027 ms]; P =0.014; FU2: 1000 ms [972–1027 ms]; P =0.044). Global extracellular volume fraction was statistically not different between patients and controls ( P =0.057). 77.8% (14/18) of patients had focal late gadolinium enhancement. T2 ratio was significantly elevated in patients with myocarditis at FU0 (2.2 [2.0–2.3] versus 1.6 [1.5–1.7]; P <0.001). The difference decreased during follow-up (FU1: 1.9 [1.7–1.9]; P =0.001 and FU2: 1.7 [1.7–1.8]; P =0.053). The diagnostic accuracy to discriminate between patients with acute myocarditis and healthy controls was 86% for T2>52 ms, 78% for native T1>981 ms, 74% for extracellular volume fraction >0.24, and 100% for T2 ratio >1.9. Conclusions— Although both T2 and T1 mapping reliably detected acute myocarditis, only T2 mapping discriminated between acute and healed stages, underlining the incremental value of T2 mapping.

Porous medium 3D flow simulation of contrast media washout in cardiac MRI reflects myocardial injury

“…The left ventricular ejection fraction and the end diastolic volume of the left ventricle were not significantly different in the acute patients compared with controls, as we have studied infarct‐type myocarditis. This suggests that the stroke volume (SV) was not on the lower range.…”

“…For the comparison of simulation to patient data, we applied the model in a recently published patient cohort . In this study of n = 18 patients with myocarditis, as defined in Ref 28, underwent 2 CMR examinations at 1.5 T. First, in the acute state of the disease (called “acute”) and after 6 months, a follow‐up examination was undertaken in the chronic state (called “healed”).…”

“…Early gadolinium enhancement was introduced first for CMR in myocarditis, and is commonly used on top of T 2 ‐weighted edema imaging to characterize the stage of disease . The imaging technique of late gadolinium enhancement as well as early gadolinium enhancement are strongly T 1 weighted and therefore will be extended with quantitative T 1 mapping . Furthermore, the early and late CM washout in the tissue of interest may be extended by a time series of images to capture the whole washout process and to decipher the CM washout kinetics.…”

The Prognostic Role of T1 Mapping Sequences: Can T1 Mapping Parameters Have a Role in Risk Stratification?

“…Regarding this question, Luetkens et al [52] reported that there was a significant and consistent decrease in all inflammatory CMR parameters over the course of the disease (p<0.01 for all parameters). Myocardial T1 and T2 relaxation times-indicative of myocardial edema-were the only single parameters showing significant differences between myocarditis patients and control subjects at the 5.5±1.3-week follow-up (native T1: 986.5±44.4 vs. 965.1± www.e-cvia.org 201 [53] reported that although both T2 and T1 mapping reliably detected acute myocarditis, only T2 mapping discriminated between acute and healed stages, underlining the incremental value of T2 mapping.…”

Myocarditis in Athletes Is a Challenge

“…T2 weighted imaging, T1 -and T2 mapping techniques LLC are now often complemented by novel CMR techniques such as native T1 and T2 mapping as well as extracellular volume fraction (ECV) measurement to provide a higher sensitivity and specificity (46,47). Native T1 mapping values are affected by both edema and extracellular expansion and is therefore able to detect myocarditis at various stages, whereas T2 mapping evaluates free water content that is normally present in the acute phase of myocarditis and then gradually normalizes over months -this is relevant for cardiac caregivers evaluating the course of myocarditis as it is the only technique that can adequately discriminate between myocarditis and noninflammatory cardiomyopathies in patients with symptoms lasting longer than 2 weeks (48,49). A recent meta-analysis by Pan et al (48) comparing the diagnostic performance of ECV, native T1 mapping and T2 mapping versus LLC for detection of acute myocarditis including 17 studies and 1308 subjects, has shown that only native T1 mapping had A c c e p t e d m a n u s c r i p t significantly better sensitivity than LLC, while other parameters had comparable diagnostic performance to LLC and provided distinct advantages for evaluating myocarditis.…”