Assessment of Myocardial 18F-FDG Uptake at PET/CT in Asymptomatic SARS-CoV-2-vaccinated and Nonvaccinated Patients.

Background Patients who developed myocarditis following SARS-CoV-2 vaccination show abnormalities on cardiac MRI. However, whether myocardial changes occur in asymptomatic individuals following vaccination is not well established. Purpose To assess myocardial 18Fluorine-fluorodeoxyglucose (18F-FDG) uptake on PET/CT in asymptomatic SARS-CoV-2 vaccinated patients compared to nonvaccinated patients. Materials and Methods This retrospective study included patients who underwent 18F-FDG PET/CT for indications unrelated to myocarditis during the period before (11/1/2020 - 2/16/2021) and after (2/17/20121 - 3/31/2022) SARS-CoV-2 vaccines were available. Myocardial and axillary FDG uptake were quantitatively assessed using maximum standardized uptake value (SUVmax). SUVmax values in all patients and in patients stratified by sex (male/female), age (<40, 41-60, >60 years), and time interval between vaccination and PET/CT were compared using Mann-Whitney U test or Kruskal-Wallis test with post ad -hoc Dwass, Steel, Critchlow-Fligner multiple comparison analysis. Results The study included 303 nonvaccinated patients (mean age, 52.9 years ± 14.9 [SD]; 157 females) and 700 vaccinated patients (mean age, 56.8 years ± 13.7 [SD]; 344 females). Vaccinated patients had overall higher myocardial FDG uptake compared to nonvaccinated patients (median SUVmax, 4.8 [IQR: 3.0-8.5] vs median SUVmax, 3.3 [IQR: 2.5-6.2]; P < .0001). Myocardial SUVmax was higher in vaccinated patients regardless of sex (median range, 4.7-4.9 [IQR: 2.9-8.6]) or patient age (median range, 4.7-5.6 [IQR: 2.9-8.6]) compared to corresponding nonvaccinated groups (sex median range, 3.2-3.9 [IQR: 2.4-7.2]; age median range, 3.3-3.3 [IQR: 2.3-6.1]; P range, <.001-.015). Furthermore, increased myocardial FDG uptake was observed in patients imaged 1-30, 31-60, 61-120, and 121-180 days after their second vaccination (median SUVmax range, 4.6-5.1 [IQR: 2.9-8.6]) and increased ipsilateral axillary uptake was observed in patients imaged 1-30, 31-60, 61-120 days after their 2nd vaccination (median SUVmax range, 1.5-2.0 [IQR: 1.2-3.4]) compared to the nonvaccinated patients (P range, <.001-<.001). Conclusion Compared to nonvaccinated patients, asymptomatic patients who received their 2nd vaccination 1-180 days prior to imaging showed increased myocardial FDG uptake on PET/CT. See also the editorial by Bluemke in this issue.

Assessment of Myocardial Mechanics in Acute Rheumatic Fever Using Speckle-Tracking Echocardiography.

BACKGROUND: This study aims to evaluate the role of speckle-tracking echocardiography to identify myocardial deformation in acute rheumatic fever. METHODS: Twenty-seven patients and 27 healthy children were prospectively evaluated. The patient group was divided into 2 subgroups based on echocardiographic findings, with or without carditis. The left ventricular global longitudinal strain and strain rate, left ventricular global circumferential strain and strain rate, and right ventricular global lon-gitudinal strain and strain rate were assessed by speckle-tracking echocardiography. RESULTS: In the acute phase of the disease, all values except the right ventricular global longitudinal strain were found to be significantly below the control group in the patient cohort. No significant difference was found between the patients grouped as carditis and non-carditis in the acute period. Comparison of the acute period with the post-treatment period revealed a significant increase in all strain values of the patients with carditis and significant increases observed in all values except left ventricular global longitudinal strain rate, left ventricular global circumferential strain rate, and right ventricular global longitudinal strain rate values in patients without carditis. Apart from the right ventricular global longitudinal strain rate, which was significantly lower in the non-carditis group compared to the control group, there was no significant difference in strain values between the patient and control groups following treatment. CONCLUSION: In the present study, we found that all patients, including patients in whom no valvular involvement was detected by echocardiography in the acute phase of acute rheumatic fever, had a lower right and left ventricular strain and strain rate measurements and that these findings improved after treatment, suggesting that strain echocardiography may be a helpful diagnostic method, especially in patients without valvular involvement.

Quantitative cardiac MRI parameters for assessment of myocarditis in children and adolescents: a systematic review and meta-analysis.

AIM: To evaluate the role of quantitative cardiac magnetic resonance imaging (CMRI) parameters in myocarditis, including acute and chronic myocarditis (AM and CM), for children and adolescents. MATERIALS AND METHODS: PRISMA principles were followed. PubMed, EMBASE, Web of Science, Cochrane Library, and grey literature were searched. The Newcastle-Ottawa Scale (NOS) and the Agency for Healthcare Research and Quality (AHRQ) checklist were utilised for quality assessment. Quantitative CMRI parameters were extracted and a meta-analysis was performed in comparison with healthy controls. The overall effect size was measured as the weighted mean difference (WMD). RESULTS: Ten quantitative CMRI parameters of seven studies were analysed. Compared with the control group, the myocarditis group reported longer native T1 relaxation time (WMD=54.00, 95% confidence interval [CI]: 33.21,74.79, p<0.001), longer T2 relaxation time (WMD=2.13, 95% CI: 0.98, 3.28, p<0.001), increased extracellular volume (ECV; WMD=3.13, 95% CI: 1.34,4.91, p=0.001), elevated early gadolinium enhancement (EGE) ratio (WMD=1.47, 95% CI: 0.65,2.28, p<0.001), and increased T2-weighted ratio (WMD=0.43, 95% CI: 0.21,0.64, p<0.001). The AM group had longer native T1 relaxation times (WMD=72.02, 95% CI: 32.78,111.27, p<0.001), increased T2-weighted ratios (WMD=0.52, 95% CI: 0.21,0.84 p=0.001), and impaired left ventricular ejection fractions (LVEF; WMD=-5.84, 95% CI: -9.69, -1.99, p=0.003). Impaired LVEF (WMD=-2.24, 95% CI: -3.32, -1.17, p<0.001) was observed in the CM group. CONCLUSION: Statistical differences can be observed in some CMRI parameters between patients with myocarditis and healthy controls; however, apart from native T1 mapping, there were no large differences in other parameters between two groups, which may reveal the limited benefit of CMRI in assessing myocarditis in children and adolescents.

Contrast-enhanced cine MR sequences in the assessment of myocardial hyperemia in acute myocarditis: can they help? A feasibility study.

The study was designed to assess the accuracy of contrast-enhanced balanced steady-state free precession (cine-SSFP) CMR imaging sequences to exhibit myocardial hyperemia in acute myocarditis, which has for a long time been investigated in some centers using early gadolinium enhancement (EGE) sequence. Contrast-enhanced cine-SSFP (CESSFP) sequences were compared to precontrast cine-SSFP sequences to calculate the early cine-contrast enhancement in 36 consecutive patients with acute myocarditis and 36 controls matched for age and gender. Four-chamber views images were obtained in each subject before and after gadolinium injection. Absolute and relative left ventricular myocardial enhancement of the overall myocardium, then separately of the lateral wall and interventricular septum was analyzed in telediastole. Myocarditis patients displayed higher cine-SSFP absolute enhancement than controls (overall left ventricular myocardium 2.38 ± 0.33 vs 1.84 ± 0.31; lateral wall 2.45 ± 0.35 vs 1.83 ± 0.32; and septum 2.26 ± 0.29 vs 1.82 ± 0.29, p < 0.0001 for all). Less significant differences were observed for the relative enhancement (p < 0.05 for all). Using ROC curves, the optimal threshold value of absolute enhancement to diagnose acute myocarditis was 2.05 (sensitivity: 86%; specificity: 81%). Given the simplicity of use, contrast-enhanced cine-SSFP sequences should be used as an additional diagnostic tool to detect hyperemia in acute myocarditis patients.

Assessment of Cardiac, Vascular, and Pulmonary Pathobiology In Vivo During Acute COVID-19.

Background Acute COVID-19-related myocardial, pulmonary, and vascular pathology and how these relate to each other remain unclear. To our knowledge, no studies have used complementary imaging techniques, including molecular imaging, to elucidate this. We used multimodality imaging and biochemical sampling in vivo to identify the pathobiology of acute COVID-19. Specifically, we investigated the presence of myocardial inflammation and its association with coronary artery disease, systemic vasculitis, and pneumonitis. Methods and Results Consecutive patients presenting with acute COVID-19 were prospectively recruited during hospital admission in this cross-sectional study. Imaging involved computed tomography coronary angiography (identified coronary disease), cardiac 2-deoxy-2-[fluorine-18]fluoro-D-glucose positron emission tomography/computed tomography (identified vascular, cardiac, and pulmonary inflammatory cell infiltration), and cardiac magnetic resonance (identified myocardial disease) alongside biomarker sampling. Of 33 patients (median age 51 years, 94% men), 24 (73%) had respiratory symptoms, with the remainder having nonspecific viral symptoms. A total of 9 patients (35%, n=9/25) had cardiac magnetic resonance-defined myocarditis. Of these patients, 53% (n=5/8) had myocardial inflammatory cell infiltration. A total of 2 patients (5%) had elevated troponin levels. Cardiac troponin concentrations were not significantly higher in patients with and without myocarditis (8.4 ng/L [interquartile range, IQR: 4.0-55.3] versus 3.5 ng/L [IQR: 2.5-5.5]; P=0.07) or myocardial cell infiltration (4.4 ng/L [IQR: 3.4-8.3] versus 3.5 ng/L [IQR: 2.8-7.2]; P=0.89). No patients had obstructive coronary artery disease or vasculitis. Pulmonary inflammation and consolidation (percentage of total lung volume) was 17% (IQR: 5%-31%) and 11% (IQR: 7%-18%), respectively. Neither were associated with the presence of myocarditis. Conclusions Myocarditis was present in a third patients with acute COVID-19, and the majority had inflammatory cell infiltration. Pneumonitis was ubiquitous, but this inflammation was not associated with myocarditis. The mechanism of cardiac pathology is nonischemic and not attributable to a vasculitic process. Registration URL: https://www.isrctn.com; Unique identifier: ISRCTN12154994.

Magnetic Resonance Imaging in Pediatric Myocarditis: Trends and Associations With Cost and Outcome.

BACKGROUND: Cardiac magnetic resonance (CMR) provides tissue characterization and structural and functional data. CMR has high sensitivity and specificity for myocarditis in adults and children. The relationship between pediatric CMR use, cost, and clinical outcome has not been studied. OBJECTIVES: This work aims to describe temporal trends in CMR imaging for pediatric myocarditis and examine associations between CMR use, hospital cost, and outcomes. METHODS: A retrospective cohort study of all inpatients <21 years of age with a diagnosis of myocarditis reported to the Pediatric Health Information System (2004-2019) was performed. Trends in CMR use were examined. A propensity-matched subcohort using center and patient level variables was used to assess whether outcomes differed by CMR use. RESULTS: A total of 4,195 children with myocarditis from 47 hospitals were identified. The median age was 11.5 years (IQR: 1.5-16.0 years) and 2,617 (62%) were male. CMR was used in 23% and mortality occurred in 6%. CMR use during hospitalization increased from 2% in 2004 to 37% in 2019 (odds ratio [OR]: 1.19 [95% CI: 1.17-1.21]). After propensity score matching, CMR use was associated with higher median cost (+$5,340 [95% CI: +$1,739 to +$9,936]) and similar median length of stay (0 days [95% CI: -1 to +1 days]). Using quantile regression, CMR was associated with lower 90th percentile cost (-$77,200 [95% CI: -$127,373 to -$31,339]). More children receiving CMR were discharged alive in the first 30 days after admission (OR: 1.89 days [95% CI: 1.28-2.29]). Within the propensity matched cohort, <10 of 790 CMR recipients died compared to 42 of 790 in the non-CMR group. CONCLUSIONS: CMR use in children with myocarditis has increased over the past 15 years. CMR use is associated with higher cost of hospitalization and similar length of stay for most children but lower cost among the sickest children. CMR use in specific patients may improve clinical outcomes at a lower cost.

Quantitative Assessment of Late Gadolinium Enhancement and Edema at Cardiac Magnetic Resonance in Low-Risk Myocarditis Patients.

In this study, we aimed to quantify LGE and edema at short-tau inversion recovery sequences on cardiac magnetic resonance (CMR) in patients with myocarditis. We retrospectively evaluated CMR examinations performed during the acute phase and at follow-up. Forty-seven patients were eligible for retrospective LGE assessment, and, among them, twenty-five patients were eligible for edema evaluation. Both groups were paired with age- and sex-matched controls. The median left ventricle LGE was 6.4% (interquartile range 5.0−9.2%) at the acute phase, 4.4% (3.3−7.2%) at follow-up, and 4.3% (3.0−5.3%) in controls, the acute phase being higher than both follow-up and controls (p < 0.001 for both), while follow-up and controls did not differ (p = 0.139). An optimal threshold of 5.0% was obtained for LGE with 87% sensitivity and 48% specificity; the positive likelihood ratio (LR) was 1.67, and the negative LR was 0.27. Edema was 12.8% (9.4−18.1%) at the acute phase, 7.3% (5.5−8.8%) at follow-up, and 6.7% (5.6−8.6%) in controls, the acute phase being higher than both follow-up and controls (both p < 0.001), while follow-up and controls did not differ (p = 0.900). An optimal threshold of 9.5% was obtained for edema with a sensitivity of 76% and a specificity of 88%; the positive LR was 6.33, and the negative LR was 0.27. LGE and edema thresholds are useful in cases of suspected mild myocarditis.

High-Spatial-Resolution 3D Whole-Heart MRI T2 Mapping for Assessment of Myocarditis.

Background Clinical guidelines recommend the use of established T2 mapping sequences to detect and quantify myocarditis and edema, but T2 mapping is performed in two dimensions with limited coverage and repetitive breath holds. Purpose To assess the reproducibility of an accelerated free-breathing three-dimensional (3D) whole-heart T2 MRI mapping sequence in phantoms and participants without a history of cardiac disease and to investigate its clinical performance in participants with suspected myocarditis. Materials and Methods Eight participants (three women, mean age, 31 years ± 4 [standard deviation]; cohort 1) without a history of cardiac disease and 25 participants (nine women, mean age, 45 years ± 17; cohort 2) with clinically suspected myocarditis underwent accelerated free-breathing 3D whole-heart T2 mapping with 100% respiratory scanning efficiency at 1.5 T. The participants were enrolled from November 2018 to August 2020. Three repeated scans were performed on 2 separate days in cohort 1. Segmental variations in T2 relaxation times of the left ventricular myocardium were assessed, and intrasession and intersession reproducibility were measured. In cohort 2, segmental myocardial T2 values, detection of focal inflammation, and map quality were compared with those obtained from clinical breath-hold two-dimensional (2D) T2 mapping. Statistical differences were assessed using the nonparametric Mann-Whitney and Kruskal-Wallis tests, whereas the paired Wilcoxon signed-rank test was used to assess subjective scores. Results Whole-heart T2 maps were acquired in a mean time of 6 minutes 53 seconds ± 1 minute 5 seconds at 1.5 mm3 resolution. Breath-hold 2D and free-breathing 3D T2 mapping had similar intrasession (mean T2 change of 3.2% and 2.3% for 2D and 3D, respectively) and intersession (4.8% and 4.9%, respectively) reproducibility. The two T2 mapping sequences showed similar map quality (P = .23, cohort 2). Abnormal myocardial segments were identified with confidence (score 3) in 14 of 25 participants (56%) with 3D T2 mapping and only in 10 of 25 participants (40%) with 2D T2 mapping. Conclusion High-spatial-resolution three-dimensional (3D) whole-heart T2 mapping shows high intrasession and intersession reproducibility and helps provide T2 myocardial characterization in agreement with clinical two-dimensional reference, while enabling 3D assessment of focal disease with higher confidence. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Friedrich in this issue.

The Role of 18FDG PET/CT in the Assessment of Endocarditis, Myocarditis and Pericarditis.

Endocarditis, myocarditis and pericarditis are a heterogeneous group of phenotypic syndromes where the culprit area of inflammation is the heart. Inflammation may be determined by an infective agent, toxins, drugs or an activated immune system. Clinical manifestations can be subtle and diagnosis remains a challenge for cardiologists, requiring high level of suspicion and advanced multimodal cardiac imaging to avoid life-threatening consequences. The purpose of this review is to report the recent advances of PET/CT imaging with 18FDG in helping the management of patients affected by inflammatory heart disease. Two independent reviewers searched in PubMed articles published before or in June 2019 and final decisions on the inclusion of references were done in consensus with a third reviewer. At the end of the selection process 23/206 articles on "cardiac inflammation"; 26/235 articles on "endocarditis", "prosthetic heart valve", "pacemaker", "implantable cardiac device"; 7/103 articles on "myocarditis"; 13/330 articles on sarcoidosis" and 2/19 articles on "pericarditis" were included. Compared with the conventional methods, molecular imaging has the advantage to non-invasively and directly trace the inflammatory process, and to identify earlier the presence and the extent of intra-cardiac and extra-cardiac involvement, to enable quantification of disease activity, guide therapeutic interventions, and monitor treatment success.

Tissue-tracking in the assessment of late gadolinium enhancement in myocarditis and myocardial infarction.

PURPOSE: To test the diagnostic performance of cardiovascular magnetic resonance (CMR) tissue-tracking (TT) to detect the presence of late gadolinium enhancement (LGE) in patients with a diagnosis of myocardial infarction (MI) or myocarditis (MYO), preserved left ventricular ejection fraction (LVEF) and no visual regional wall motion abnormalities (RWMA). METHODS: We selected consecutive CMR studies of 50 MI, 50 MYO and 96 controls. Receiving operating characteristic (ROC) curve and net reclassification index (NRI) analyses were used to assess the predictive ability and the incremental diagnostic yield of 2D and 3D TT-derived strain parameters for the detection of LGE and to measure the best cut-off values of strain parameters. RESULTS: Overall, cases showed significantly reduced 2D global longitudinal strain (2D-GLS) values compared with controls (-20.1 ± 3.1% vs -21.6 ± 2.7%; p = 0.0008). 2D-GLS was also significantly reduced in MYO patients compared with healthy controls (-19.7 ± 2.9% vs -21.9 ± 2.4%; p = 0.0001). 3D global radial strain (3D-GRS) was significantly reduced in MI patients compared with controls with risk factors (34.3 ± 11.8% vs 40.3 ± 12.5%, p = 0.024) Overall, 2D-GLS yielded good diagnostic accuracy for the detection of LGE in the MYO subgroup (AUROC 0.79; NRI (95% CI) = 0.6 (0.3, 1.02) p = 0.0004), with incremental predictive value beyond risk factors and LV function parameters (p for AUROC difference = 0.048). In the MI subgroup, 2D-GRS (AUROC 0.81; NRI (95% CI) = 0.56 (0.17, 0.95) p = 0.004), 3D-GRS (AUROC 0.82; NRI (95% CI) = 0.57 (0.17, 0.97) p = 0.006) and 3D global circumferential strain (3D-GCS) (AUROC 0.81; NRI (95% CI) = 0.62 (0.22, 1.01) p = 0.002) emerged as potential markers of disease. The best cut-off for 2D-GLS was -21.1%, for 2D- and 3D-GRS were 39.1% and 37.7%, respectively, and for 3D-GCS was -16.4%. CONCLUSIONS: At CMR-tissue tracking analysis, 2D-GLS was a significant predictor of LGE in patients with myocarditis but preserved LVEF and no visual RWMA. Both 2D- and 3D-GRS and 2D-GCS yielded good diagnostic accuracy for LGE detection in patients with previous MI but preserved LVEF and no visual RWMA.

High inter- and intra-observer agreement in mapping sequences compared to classical Lake Louise Criteria assessment of myocarditis by inexperienced observers.

AIM: To investigate the observer agreement for the assessment of chronic myocarditis by native T1 and T2 relaxation times, post-contrast T1 relaxation time, and extracellular volume (ECV) fraction, compared to Lake Louise Criteria: oedema ratio (OR) and early gadolinium enhancement ratio (EGEr). MATERIALS AND METHODS: Data were collected retrospectively on 71 consecutive patients who underwent cardiac magnetic resonance imaging as part of a complete diagnostic work-up according to current guidelines for suspected myocarditis. Thirteen cases were excluded due to previous myocardial infarction or technical issues. To test for intra- and interobserver agreement, the determination of the myocardial native T1 and T2 relaxation times, post-contrast T1 relaxation time, ECV, OR and EGEr was undertaken by two medical school graduates after comprehensive training. Bland-Altman analysis and intraclass correlation coefficient (ICC) were assessed. RESULTS: The final analysis included 27 patients with chronic myocarditis, 21 patients with dilated cardiomyopathy and/or hypertensive heart disease, and 10 patients with unremarkable investigations in the control group. Excellent interobserver agreement was obtained for native T1 and T2 relaxation times, post-contrast T1 relaxation time and ECV, with ICC of 0.982/0.977/0.991/0.994, p < 0.001. Interobserver agreement was lower for OR and EGEr, with ICC of 0.841 and 0.818, p < 0.001, respectively. Mapping parameters (cut-off values: T1 1,070 ms, T2 54 ms, ECV 30%) yield good performance in the diagnosis of chronic myocarditis with the best sensitivity/specificity/accuracy of 93%/80%/88% for ECV, followed by 70%/80%/74% for T2, and 52%/88%/69% for T1. CONCLUSIONS: mapping parameters show excellent agreement between observers in the assessment of myocarditis.

Recent Advances in T1 and T2 Mapping in the Assessment of Fulminant Myocarditis by Cardiac Magnetic Resonance.

PURPOSE OF REVIEW: This review was undertaken to summarise recent data relating to T1 and T2 relaxation times in the assessment of myocarditis using cardiac MRI, and the effect new studies have had on the established diagnostic criteria, leading to recently proposed revised criteria for the cardiac MRI assessment of myocarditis. RECENT FINDINGS: In 2018, updates to the 2009 Lake Louise Criteria (LLC) were proposed, based on studies showing improved accuracy of T1 mapping techniques over T1 signal intensity ratio-based imaging, although for the detection of myocardial oedema either T2-weighted images or increased T2 relaxation times can be used. Non-ischaemic distribution of scar on late gadolinium-enhanced (LGE) T1-weighted imaging remains in the newly revised criteria, which, although can have low sensitivity due to fibrosis presenting diffusely or due to CMR being performed early in the disease process before scar formation, remains in the LLC due to its high specificity. Early gadolinium enhancement has been removed from the LLC, as T1 quantification has higher diagnostic accuracy for the detection of myocardial injury. In the CMR assessment of myocarditis, T1 and T2 quantifications are now recommended over T1- and T2-weighted imaging. Late gadolinium enhancement in a non-ischaemic pattern remains in the updated criteria, whereas early gadolinium enhancement has been superseded by T1 quantification.

Impact of baseline calibration on semiquantitative assessment of myocardial perfusion reserve by adenosine stress MRI.

In this study, we sought to investigate the impact of baseline calibration, which is used in quantitative cardiac MRI perfusion analysis to correct for surface coil inhomogeneity and noise, on myocardial perfusion reserve index (MPRI) and its contribution to previously reported paradoxical low MPRI < 1.0 in patients with unobstructed coronary arteries. Semiquantitative perfusion analysis was performed in 20 patients with unobstructed coronary arteries undergoing stress/rest perfusion CMR and in ten patients undergoing paired rest perfusion CMR. The following baseline calibration settings were compared: (1) baseline division, (2) baseline subtraction and (3) no baseline calibration. In uncalibrated analysis, we observed ~ 20% segmental dispersion of signal intensity (SI)-over-time curves. Both baseline subtraction and baseline division reduced relative dispersion of t0-SI (p < 0.001), but only baseline division corrected for dispersion of peak-SI and maximum upslope also (p < 0.001). In the assessment of perfusion indices, however, baseline division resulted in paradoxical low MPRI (1.01 ± 0.23 vs. 1.63 ± 0.38, p < 0.001) and rest perfusion index (RPI 0.54 ± 0.07 vs. 0.94 ± 0.12, p < 0.001), respectively. This was due to a reversed ratio of blood-pool and myocardial baseline-SI before the second perfusion study caused by circulating contrast agent from the first injection. In conclusion, baseline division reliably corrects for inhomogeneity of the surface coil sensitivity profile facilitating comparisons of regional myocardial perfusion during hyperemia or at rest. However, in the assessment of MPRI, baseline division can lead to paradoxical low results (even MPRI < 1.0 in patients with unobstructed coronary arteries) potentially mimicking severely impaired perfusion reserve. Thus, in the assessment of MPRI we propose to waive baseline calibration.

The assessment of treatment outcomes in patients with acute viral myocarditis by speckle tracking and tissue Doppler methods.

OBJECTIVES: The aim was to evaluate the role of tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE), to identify myocardial dysfunction, and to evaluate myocardial segmental deformation in acute viral myocarditis. METHODS: Twenty-one patients and twelve healthy children were studied prospectively. The TDI and STE were performed before and after treatment. The myocardial velocities (Sm , Em , and Am ) and time intervals (isovolumic contraction, isovolumic relaxation, and ejection times [ET]) at interventricular septum (IVS), left, and right ventricular basal segments were examined by TDI. The left ventricular global longitudinal strain (LVGLS) and strain rate (LVGLSR), left ventricular global circumferential strain (LVGCS) and strain rate (LVGCSR), and right ventricular global longitudinal strain (RVGLS) and strain rate (RVGLSR) were examined by STE. RESULTS: Sm and Em at IVS and at LV, ET at IVS, ET at RV, ET at LV were significantly lower in patients before treatment than controls. LVGLS, LVGLSR, LVGCS, LVGCSR, RVGLS, RVGLSR were significantly decreased in patients before treatment than controls. There was significant improvement for LVGLS, LVGLSR, LVGCS, LVGCSR, and RVGLS in patients after treatment. Sm , Em , and Am at LV were significantly lower in patients before treatment than in patients after treatment. In spite of improvements, Sm , Em , and ET at IVS, LVGLS, LVGLSR, LVGCS, LVGCSR were significantly lower in patients after treatment than controls. CONCLUSIONS: The TDI and STE were useful methods for detection of early myocardial dysfunction and evaluation of treatment outcomes in acute viral myocarditis.

Assessment of Myocarditis: Cardiac MR, PET/CT, or PET/MR?

PURPOSE OF REVIEW: Diagnosis of myocarditis is challenging given its variable clinical manifestations and non-specific laboratory findings. Cardiac magnetic resonance (MR) is currently the preferred imaging modality for the diagnosis of myocarditis. 18F-fluoro-deoxy-glucose (FDG) positron emission tomography/computed tomography (PET/CT), as a functional imaging tool, has a potential role in the assessment of myocarditis by detecting the underlying myocardial inflammatory activity. Data are accumulating that simultaneous cardiac PET/MR may have complementary and incremental values for the evaluation of myocarditis compared to PET/CT or cardiac MR alone. The article aims to summarize the findings in the literature and discuss future directions of cardiac PET/MR for myocarditis. RECENT FINDINGS: The Lake Louis Criteria (CLL) of cardiac MR is widely used for the diagnosis of myocarditis. It has an overall acceptable sensitivity of 67% and specificity of 91% for acute myocarditis but does not have the same accuracy for chronic myocarditis. FDG PET/CT is capable of assessing myocarditis by providing metabolic information of inflammation as increased myocardial FDG uptake. In addition to reduced radiation exposure, FDG PET performed on a hybrid PET/MR may detect more myocarditis than FDG PET/CT, because of the delayed PET acquisition time on PET/MR. Case-based observations and small clinical studies of FDG PET/MR have shown that FDG PET findings as abnormally increased myocardial uptake correlate well with the cardiac MR biomarkers. FDG PET findings may add complementary and incremental values to cardiac MR by improving the sensitivity of cardiac MR for mild or borderline myocarditis, and increasing specificity for chronic myocarditis. Preliminary data from retrospective and case-based observational studies have suggested the complementary and incremental values of simultaneous cardiac FDG PET/MR for evaluation of myocarditis, compared to PET/CT or MR alone. Well-designed studies are needed to confirm the findings and to assess the value of cardiac PET/MR for clinical management and more importantly patient's outcome in both acute and chronic myocarditis.