COVID-19 in patients with heart failure: the new and the old epidemic.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has spread in nearly 200 countries in less than 4 months since its first identification; accordingly, the coronavirus disease 2019 (COVID 2019) has affirmed itself as a clinical challenge. The prevalence of pre-existing cardiovascular diseases in patients with COVID19 is high and this dreadful combination dictates poor prognosis along with the higher risk of intensive care mortality. In the setting of chronic heart failure, SARS-CoV-2 can be responsible for myocardial injury and acute decompensation through various mechanisms. Given the clinical and epidemiological complexity of COVID-19, patiens with heart failure may require particular care since the viral infection has been identified, considering an adequate re-evaluation of medical therapy and a careful monitoring during ventilation.

Lung Ultrasound for the Diagnosis and Management of Acute Respiratory Failure.

For critically ill patients with acute respiratory failure (ARF), lung ultrasound (LUS) has emerged as an indispensable tool to facilitate diagnosis and rapid therapeutic management. In ARF, there is now evidence to support the use of LUS to diagnose pneumothorax, acute respiratory distress syndrome, cardiogenic pulmonary edema, pneumonia, and acute pulmonary embolism. In addition, the utility of LUS has expanded in recent years to aid in the ongoing management of critically ill patients with ARF, providing guidance in volume status and fluid administration, titration of positive end-expiratory pressure, and ventilator liberation. The aims of this review are to examine the basic foundational concepts regarding the performance and interpretation of LUS, and to appraise the current literature supporting the use of this technique in the diagnosis and continued management of patients with ARF.

Characterization of edema after cryo and radiofrequency ablations based on serial magnetic resonance imaging.

INTRODUCTION: Radiofrequency (RF) and cryoablation are routinely used to treat arrhythmias, but the extent and time course of edema associated with the two different modalities is unknown. Our goal was to follow the lesion maturation and edema formation after RF and cryoablation using serial magnetic resonance imaging (MRI). METHODS AND RESULTS: Ventricular ablation was performed in a canine model (n = 11) using a cryo or an irrigated RF catheter. T2-weighted (T2w) edema imaging and late gadolinium enhancement (LGE)-MRI were done immediately (0 day: acute), 1 to 2 weeks (subacute), and 8 to 12 weeks (chronic) after ablation. After the final MRI, excised hearts underwent pathological evaluation. As a result, 45 ventricular lesions (cryo group: 20; RF group: 25) were evaluated. Acute LGE volume was not significantly different but acute edema volume in cryo group was significantly smaller (1225.0 ± 263.5 vs 1855.2 ± 520.5 mm3 ; P = 0.01). One week after ablation, edema still existed in both group but was similar in size. Two weeks after ablation there was no edema in either of the groups. In the chronic phase, the lesion volume for cryo and RF in LGE-MRI (296.7 ± 156.4 vs 281.6 ± 140.8 mm3 ; P = 0.73); and pathology (243.3 ± 125.9 vs 214.5 ± 148.6 mm3 ; P = 0.49), as well as depth, was comparable. CONCLUSIONS: When comparing cryo and RF lesions of similar chronic size, acute edema is larger for RF lesions. Edema resolves in both cryo and RF lesions in 1 to 2 weeks.

T2STIR preparation for single-shot cardiovascular magnetic resonance myocardial edema imaging.

BACKGROUND: Myocardial edema in acute myocardial infarction (AMI) is commonly imaged using dark-blood short tau inversion recovery turbo spin echo (STIR-TSE) cardiovascular magnetic resonance (CMR). The technique is sensitive to cardiac motion and coil sensitivity variation, leading to myocardial signal nonuniformity and impeding reliable depiction of edematous tissues. T2-prepared balanced steady state free precession (T2p-bSSFP) imaging has been proposed, but its contrast is low, and averaging is commonly needed. T2 mapping is useful but requires a long scan time and breathholding. We propose here a single-shot magnetization prepared sequence that increases the contrast between edema and normal myocardium and apply it to myocardial edema imaging. METHODS: A magnetization preparation module (T2STIR) is designed to exploit the simultaneous elevation of T1 and T2 in edema to improve the depiction of edematous myocardium. The module tips magnetization down to the -z axis after T2 preparation. Transverse magnetization is sampled at the fat null point using bSSFP readout and allows for single-shot myocardial edema imaging. The sequence (T2STIR-bSSFP) was studied for its contrast behavior using simulation and phantoms. It was then evaluated on 7 healthy subjects and 7 AMI patients by comparing it to T2p-bSSFP and T2 mapping using the contrast-to-noise ratio (CNR) and the contrast ratio as performance indices. RESULTS: In simulation and phantom studies, T2STIR-bSSFP had improved contrast between edema and normal myocardium compared with the other two edema imaging techniques. In patients, the CNR of T2STIR-bSSFP was higher than T2p-bSSFP (5.9 ± 2.6 vs. 2.8 ± 2.0, P < 0.05) but had no significant difference compared with that of the T2 map (T2 map: 6.6 ± 3.3 vs. 5.9 ± 2.6, P = 0.62). The contrast ratio of T2STIR-bSSFP (2.4 ± 0.8) was higher than that of the T2 map (1.3 ± 0.1, P < 0.01) and T2p-bSSFP (1.4 ± 0.5, P < 0.05). CONCLUSION: T2STIR-bSSFP has improved contrast between edematous and normal myocardium compared with commonly used bSSFP-based edema imaging techniques. T2STIR-bSSFP also differentiates between fat that was robustly suppressed and fluids around the heart. The technique is useful for single-shot edema imaging in AMI patients.

Higher contact force during radiofrequency ablation leads to a much larger increase in edema as compared to chronic lesion size.

INTRODUCTION: Reversible edema is a part of any radiofrequency ablation but its relationship with contact force is unknown. The goal of this study was to characterize through histology and MRI, acute and chronic ablation lesions and reversible edema with contact force. METHODS AND RESULTS: In a canine model (n = 14), chronic ventricular lesions were created with a 3.5-mm tip ThermoCool SmartTouch (Biosense Webster) catheter at 25 W or 40 W for 30 seconds. Repeat ablation was performed after 3 months to create a second set of lesions (acute). Each ablation procedure was followed by in vivo T2-weighted MRI for edema and late-gadolinium enhancement (LGE) MRI for lesion characterization. For chronic lesions, the mean scar volumes at 25 W and 40 W were 77.8 ± 34.5 mm3 (n = 24) and 139.1 ± 69.7 mm3 (n = 12), respectively. The volume of chronic lesions increased (25 W: P < 0.001, 40 W: P < 0.001) with greater contact force. For acute lesions, the mean volumes of the lesion were 286.0 ± 129.8 mm3 (n = 19) and 422.1 ± 113.1 mm3 (n = 16) for 25 W and 40 W, respectively (P < 0.001 compared to chronic scar). On T2-weighted MRI, the acute edema volume was on average 5.6-8.7 times higher than the acute lesion volume and increased with contact force (25 W: P = 0.001, 40 W: P = 0.011). CONCLUSION: With increasing contact force, there is a marginal increase in lesion size but accompanied with a significantly larger edema. The reversible edema that is much larger than the chronic lesion volume may explain some of the chronic procedure failures.

Dynamic changes in injured myocardium, very early after acute myocardial infarction, quantified using T1 mapping cardiovascular magnetic resonance.

BACKGROUND: It has recently been suggested that myocardial oedema follows a bimodal pattern early post ST-segment elevation myocardial infarction (STEMI). Yet, water content, quantified using tissue desiccation, did not return to normal values unlike oedema quantified by cardiovascular magnetic resonance (CMR) imaging. We studied the temporal changes in the extent and intensity of injured myocardium using T1-mapping technique within the first week after STEMI. METHODS: A first group (n = 31) underwent 3 acute 3 T CMR scans (time-point (TP) < 3 h, 24 h and 6 days), including cine, native shortened modified look-locker inversion recovery T1 mapping, T2* mapping and late gadolinium enhancement (LGE). A second group (n = 17) had a single scan at 24 h with an additional T2-weighted sequence to assess the difference in the extent of area-at-risk (AAR) compared to T1-mapping. RESULTS: The mean T1 relaxation time value within the AAR of the first group was reduced after 24 h (P < 0.001 for TP1 vs.TP2) and subsequently increased at 6 days (P = 0.041 for TP2 vs.TP3). However, the extent of AAR quantified using T1-mapping did not follow the same course, and no change was detected between TP1&TP2 (P = 1.0) but was between TP2 &TP3 (P = 0.019). In the second group, the extent of AAR was significantly larger on T1-mapping compared to T2-weighted (42 ± 15% vs. 39 ± 15%, P = 0.025). No change in LGE was detected while microvascular obstruction and intra-myocardial haemorrhage peaked at different time points within the first week of reperfusion. CONCLUSION: The intensity of oedema post-STEMI followed a bimodal pattern; while the extent of AAR did not track the same course. This discrepancy has implications for use of CMR in this context and may explain the previously reported disagreement between oedema quantified by imaging and tissue desiccation.

Relationship between CMR-derived parameters of ischemia/reperfusion injury and the timing of CMR after reperfused ST-segment elevation myocardial infarction.

BACKGROUND: To investigate the influence of cardiovascular magnetic resonance (CMR) timing after reperfusion on CMR-derived parameters of ischemia/reperfusion (I/R) injury in patients with ST-segment elevation myocardial infarction (STEMI). METHODS: The study included 163 reperfused STEMI patients undergoing CMR during the index hospitalization. Patients were divided according to the time between revascularization and CMR (Trevasc-CMR: Tertile-1 ≤ 43; 43 < Tertile-2 ≤ 93; Tertile-3 > 93 h). T2-mapping derived area-at-risk (AAR) and intramyocardial-hemorrhage (IMH), and late gadolinium enhancement (LGE)-derived infarct size (IS) and microvascular obstruction (MVO) were quantified. T1-mapping was performed before and > 15 min after Gd-based contrast-agent administration yielding extracellular volume (ECV) of infarct. RESULTS: Main factors influencing I/R injury were homogenously balanced across Trevasc-CMR tertiles. T2 values of infarct and remote regions increased with increasing Trevasc-CMR tertiles (infarct: 60.0 ± 4.9 vs 63.5 ± 5.6 vs 64.8 ± 7.5 ms; P < 0.001; remote: 44.3 ± 2.8 vs 46.1 ± 2.8 vs ± 46.1 ± 3.0; P = 0.001). However, T2 value of infarct largely and significantly exceeded that of remote myocardium in each tertile yielding comparable T2-mapping-derived AAR extent throughout Trevasc-CMR tertiles (17 ± 9% vs 19 ± 9% vs 18 ± 8% of LV, respectively, P = 0.385). Similarly, T2-mapping-based IMH detection and quantification were independent of Trevasc-CMR. LGE-derived IS and MVO were not influenced by Trevasc-CMR (IS: 12 ± 9% vs 12 ± 9% vs 14 ± 9% of LV, respectively, P = 0.646). In 68 patients without MVO, T1-mapping based ECV of infarct region was comparable across Trevasc-CMR tertiles (P = 0.470). CONCLUSION: In STEMI patients, T2 values of infarct and remote myocardium increase with increasing CMR time after revascularization. However, these changes do not give rise to substantial variation of T2-mapping-derived AAR size nor of other CMR-based parameters of I/R. TRIAL REGISTRATION: ISRCTN03522116 . Registered 30.4.2018 (retrospectively registered).

Cardiovascular magnetic resonance guided ablation and intra-procedural visualization of evolving radiofrequency lesions in the left ventricle.

BACKGROUND: Radiofrequency (RF) ablation has become a mainstay of treatment for ventricular tachycardia, yet adequate lesion formation remains challenging. This study aims to comprehensively describe the composition and evolution of acute left ventricular (LV) lesions using native-contrast cardiovascular magnetic resonance (CMR) during CMR-guided ablation procedures. METHODS: RF ablation was performed using an actively-tracked CMR-enabled catheter guided into the LV of 12 healthy swine to create 14 RF ablation lesions. T2 maps were acquired immediately post-ablation to visualize myocardial edema at the ablation sites and T1-weighted inversion recovery prepared balanced steady-state free precession (IR-SSFP) imaging was used to visualize the lesions. These sequences were repeated concurrently to assess the physiological response following ablation for up to approximately 3 h. Multi-contrast late enhancement (MCLE) imaging was performed to confirm the final pattern of ablation, which was then validated using gross pathology and histology. RESULTS: Edema at the ablation site was detected in T2 maps acquired as early as 3 min post-ablation. Acute T2-derived edematous regions consistently encompassed the T1-derived lesions, and expanded significantly throughout the 3-h period post-ablation to 1.7 ± 0.2 times their baseline volumes (mean ± SE, estimated using a linear mixed model determined from n = 13 lesions). T1-derived lesions remained approximately stable in volume throughout the same time frame, decreasing to 0.9 ± 0.1 times the baseline volume (mean ± SE, estimated using a linear mixed model, n = 9 lesions). CONCLUSIONS: Combining native T1- and T2-based imaging showed that distinctive regions of ablation injury are reflected by these contrast mechanisms, and these regions evolve separately throughout the time period of an intervention. An integrated description of the T1-derived lesion and T2-derived edema provides a detailed picture of acute lesion composition that would be most clinically useful during an ablation case.

Re-evaluation of a novel approach for quantitative myocardial oedema detection by analysing tissue inhomogeneity in acute myocarditis using T2-mapping.

OBJECTIVES: To re-evaluate a recently suggested approach of quantifying myocardial oedema and increased tissue inhomogeneity in myocarditis by T2-mapping. METHODS: Cardiac magnetic resonance data of 99 patients with myocarditis were retrospectively analysed. Thirthy healthy volunteers served as controls. T2-mapping data were acquired at 1.5 T using a gradient-spin-echo T2-mapping sequence. T2-maps were segmented according to the 16-segments AHA-model. Segmental T2-values, segmental pixel-standard deviation (SD) and the derived parameters maxT2, maxSD and madSD were analysed and compared to the established Lake Louise criteria (LLC). RESULTS: A re-estimation of logistic regression models revealed that all models containing an SD-parameter were superior to any model containing global myocardial T2. Using a combined cut-off of 1.8 ms for madSD + 68 ms for maxT2 resulted in a diagnostic sensitivity of 75% and specificity of 80% and showed a similar diagnostic performance compared to LLC in receiver-operating-curve analyses. Combining madSD, maxT2 and late gadolinium enhancement (LGE) in a model resulted in a superior diagnostic performance compared to LLC (sensitivity 93%, specificity 83%). CONCLUSIONS: The results show that the novel T2-mapping-derived parameters exhibit an additional diagnostic value over LGE with the inherent potential to overcome the current limitations of T2-mapping. KEY POINTS: • A novel quantitative approach to myocardial oedema imaging in myocarditis was re-evaluated. • The T2-mapping-derived parameters maxT2 and madSD were compared to traditional Lake-Louise criteria. • Using maxT2 and madSD with dedicated cut-offs performs similarly to Lake-Louise criteria. • Adding maxT2 and madSD to LGE results in further increased diagnostic performance. • This novel approach has the potential to overcome the limitations of T2-mapping.

Feature-tracking myocardial strain analysis in acute myocarditis: diagnostic value and association with myocardial oedema.

OBJECTIVES: To investigate the diagnostic value of cardiac magnetic resonance (CMR) feature-tracking (FT) myocardial strain analysis in patients with suspected acute myocarditis and its association with myocardial oedema. METHODS: Forty-eight patients with suspected acute myocarditis and 35 control subjects underwent CMR. FT CMR analysis of systolic longitudinal (LS), circumferential (CS) and radial strain (RS) was performed. Additionally, the protocol allowed for the assessment of T1 and T2 relaxation times. RESULTS: When compared with healthy controls, myocarditis patients demonstrated reduced LS, CS and RS values (LS: -19.5 ± 4.4% vs. -23.6 ± 3.1%, CS: -23.0 ± 5.8% vs. -27.4 ± 3.4%, RS: 28.9 ± 8.5% vs. 32.4 ± 7.4%; P < 0.05, respectively). LS (T1: r = 0.462, P < 0.001; T2: r = 0.436, P < 0.001) and CS (T1: r = 0.429, P < 0.001; T2: r = 0.467, P < 0.001) showed the strongest correlations with T1 and T2 relaxations times. Area under the curve of LS (0.79) was higher compared with those of CS (0.75; P = 0.478) and RS (0.62; P = 0.008). CONCLUSIONS: FT CMR myocardial strain analysis might serve as a new tool for assessment of myocardial dysfunction in the diagnostic work-up of patients suspected of having acute myocarditis. Especially, LS and CS show a sufficient diagnostic performance and were most closely correlated with CMR parameters of myocardial oedema. KEY POINTS: • Myocardial strain measures are considerably reduced in patients with suspected myocarditis. • Myocardial strain measures can sufficiently discriminate between diseased and healthy patients. • Myocardial strain measures show basic associations with the extent of myocardial oedema/inflammation.

Quantification of both the area-at-risk and acute myocardial infarct size in ST-segment elevation myocardial infarction using T1-mapping.

BACKGROUND: A comprehensive cardiovascular magnetic resonance (CMR) in reperfused ST-segment myocardial infarction (STEMI) patients can be challenging to perform and can be time-consuming. We aimed to investigate whether native T1-mapping can accurately delineate the edema-based area-at-risk (AAR) and post-contrast T1-mapping and synthetic late gadolinium (LGE) images can quantify MI size at 1.5 T. Conventional LGE imaging and T2-mapping could then be omitted, thereby shortening the scan duration. METHODS: Twenty-eight STEMI patients underwent a CMR scan at 1.5 T, 3 ± 1 days following primary percutaneous coronary intervention. The AAR was quantified using both native T1 and T2-mapping. MI size was quantified using conventional LGE, post-contrast T1-mapping and synthetic magnitude-reconstructed inversion recovery (MagIR) LGE and synthetic phase-sensitive inversion recovery (PSIR) LGE, derived from the post-contrast T1 maps. RESULTS: Native T1-mapping performed as well as T2-mapping in delineating the AAR (41.6 ± 11.9% of the left ventricle [% LV] versus 41.7 ± 12.2% LV, P = 0.72; R2 0.97; ICC 0.986 (0.969-0.993); bias -0.1 ± 4.2% LV). There were excellent correlation and inter-method agreement with no bias, between MI size by conventional LGE, synthetic MagIR LGE (bias 0.2 ± 2.2%LV, P = 0.35), synthetic PSIR LGE (bias 0.4 ± 2.2% LV, P = 0.060) and post-contrast T1-mapping (bias 0.3 ± 1.8% LV, P = 0.10). The mean scan duration was 58 ± 4 min. Not performing T2 mapping (6 ± 1 min) and conventional LGE (10 ± 1 min) would shorten the CMR study by 15-20 min. CONCLUSIONS: T1-mapping can accurately quantify both the edema-based AAR (using native T1 maps) and acute MI size (using post-contrast T1 maps) in STEMI patients without major cardiovascular risk factors. This approach would shorten the duration of a comprehensive CMR study without significantly compromising on data acquisition and would obviate the need to perform T2 maps and LGE imaging.

Synthetic hematocrit derived from the longitudinal relaxation of blood can lead to clinically significant errors in measurement of extracellular volume fraction in pediatric and young adult patients.

BACKGROUND: Extracellular volume fraction (ECV) is altered in pathological cardiac remodeling and predicts death and arrhythmia. ECV can be quantified using cardiovascular magnetic resonance (CMR) T1 mapping but calculation requires a measured hematocrit (Hct). The longitudinal relaxation of blood has been used in adults to generate a synthetic Hct (estimate of true Hct) but has not been validated in pediatric populations. METHODS: One hundred fourteen children and young adults underwent a total of 163 CMRs with T1 mapping. The majority of subjects had a measured Hct the same day (N = 146). Native and post-contrast T1 were determined in blood pool, septum, and free wall of mid-LV, avoiding areas of late gadolinium enhancement. Synthetic Hct and ECV were calculated and intraclass correlation coefficient (ICC) and linear regression were used to compare measured and synthetic values. RESULTS: The mean age was 16.4 ± 6.4 years and mean left ventricular ejection fraction was 59% ± 9%. The mean measured Hct was 41.8 ± 3.0% compared to the mean synthetic Hct of 43.2% ± 2.9% (p < 0.001, ICC 0.46 [0.27, 0.52]) with the previously published model and 41.8% ± 1.4% (p < 0.001, ICC 0.28 [0.13, 0. 42]) with the locally-derived model. Mean measured mid-free wall ECV was 30.5% ± 4.8% and mean synthetic mid-free wall ECV of local model was 29.7% ± 4.6% (p < 0.001, ICC 0.93 [0.91, 0.95]). Correlations were not affected by heart rate and did not significantly differ in subpopulation analysis. While the ICC was strong, differences between measured and synthetic ECV ranged from -8.4% to 4.3% in the septum and -12.6% to 15.8% in the free wall. Using our laboratory's normal cut-off of 28.5%, 59 patients (37%) were miscategorized (53 false negatives, 6 false positives) with published model ECV. The local model had 37 miscategorizations (20 false negatives, 17 false positives), significantly fewer but still a substantial number (23%). CONCLUSIONS: Our data suggest that use of synthetic Hct for the calculation of ECV results in miscategorization of individual patients. This difference may be less significant once synthetic ECV is calculated and averaged over a large research cohort, making it potentially useful as a research tool. However, we recommend formal measurement of Hct in children and young adults for clinical CMRs.

Hemorrhage promotes inflammation and myocardial damage following acute myocardial infarction: insights from a novel preclinical model and cardiovascular magnetic resonance.

BACKGROUND: Myocardial hemorrhage is a frequent complication following reperfusion in acute myocardial infarction and is predictive of adverse outcomes. However, it remains unsettled whether hemorrhage is simply a marker of a severe initial ischemic insult or directly contributes to downstream myocardial damage. Our objective was to evaluate the contribution of hemorrhage towards inflammation, microvascular obstruction and infarct size in a novel porcine model of hemorrhagic myocardial infarction using cardiovascular magnetic resonance (CMR). METHODS: Myocardial hemorrhage was induced via direct intracoronary injection of collagenase in a novel porcine model of ischemic injury. Animals (N = 27) were subjected to coronary balloon occlusion followed by reperfusion and divided into three groups (N = 9/group): 8 min ischemia with collagenase (+HEM); 45 min infarction with saline (I-HEM); and 45 min infarction with collagenase (I+HEM). Comprehensive CMR was performed on a 3 T scanner at baseline and 24 h post-intervention. Cardiac function was quantified by cine imaging, edema/inflammation by T2 mapping, hemorrhage by T2* mapping and infarct/microvascular obstruction size by gadolinium enhancement. Animals were subsequently sacrificed and explanted hearts underwent histopathological assessment for ischemic damage and inflammation. RESULTS: At 24 h, the +HEM group induced only hemorrhage, the I-HEM group resulted in a non-hemorrhagic infarction, and the I+HEM group resulted in infarction and hemorrhage. Notably, the I+HEM group demonstrated greater hemorrhage and edema, larger infarct size and higher incidence of microvascular obstruction. Interestingly, hemorrhage alone (+HEM) also resulted in an observable inflammatory response, similar to that arising from a mild ischemic insult (I-HEM). CMR findings were in good agreement with histological staining patterns. CONCLUSIONS: Hemorrhage is not simply a bystander, but an active modulator of tissue response, including inflammation and microvascular and myocardial damage beyond the initial ischemic insult. A mechanistic understanding of the pathophysiology of reperfusion hemorrhage will potentially aid better management of high-risk patients who are prone to adverse long-term outcomes.

Assessment of edema using STIR+ via 3D cardiovascular magnetic resonance imaging in patients with suspected myocarditis.

OBJECTIVE: To evaluate three-dimensional T2-weighted fast spin echo triple inversion recovery sequences (STIR+) for the diagnosis of myocardial edema in patients with suspected early myocarditis after respiratory or gastrointestinal tract viral infection and at follow-up. MATERIALS AND METHODS: We prospectively examined 28 patients with suspected myocarditis and 37 controls matched for gender and age. An ECG-triggered STIR+ was used to cover the entire left ventricle in short-axis images with 10-mm slice thickness and no interslice gap. The global signal intensity ratio (heart muscle in relation to skeletal muscle) was calculated (global STIR+ ratio) to evaluate edema. All patients had repeat examinations at follow-up (mean interval 4.9 months, 1-12 months). RESULTS: The mean global STIR+ ratio was 2.15 ± 0.4 in the initial examination of patients as compared to 1.78 ± 0.3 in controls (p < 0.0001) and 1.89 ± 0.3 in patients at follow-up (p = 0.0001 vs. first visit). Left ventricular ejection fraction did not differ between patients and controls at baseline and at follow-up. CONCLUSION: We could identify a significantly higher global STIR+ ratio in patients with suspected myocarditis compared to controls, and a dynamic change during follow-up. The global STIR+ ratio may, therefore, be useful for the diagnosis of myocarditis and should be further explored.

Signal decay mapping of myocardial edema using dual-contrast fast spin-echo MRI.

PURPOSE: To introduce a dual-contrast fast spin-echo (dcFSE) sequence for signal decay mapping of myocardial edema. MATERIALS AND METHODS: After consultation with the Institutional Review Board, 22 acute myocardial infarction (MI) patients were examined with magnetic resonance imaging (MRI) at 1.5T 2 days after revascularization. Edema was evaluated in 16 myocardial segments with an exponential fit for signal decay time (SDT) in dcFSE mapping and T2 signal intensity ratio for single-contrast FSE. Myocardial viability was evaluated in late gadolinium enhancement (LGE). A control group of 10 volunteers was examined for edema imaging. SDT was compared in segment groups: 1) with LGE in MI, 2) penumbra, 3) remote from LGE, 4) controls. Groups 1/3 and 3/4 were tested on difference. Three phantoms providing similar T2 but different T1 relaxation times (low, intermediate, high) were examined with dcFSE and multicontrast spin echo sequence as a reference. RESULTS: The SDT/T2 ratio for segment groups was 1) 82msec/1.7 in segments with LGE; 2) 65msec/1.6 for penumbra, 3) 62msec/1.7 for remote segments, and 4) 50msec/1.6 in controls. In dcFSE group 1/3 (P < 0.0001) and in group 3/4 (P = 0.0002) SDT was significantly different. In single-contrast FSE the T2 ratio was not significantly different for both tests: 1/3 P = 0.1889; 3/4 P = 0.8879. T2 -overestimation of dcFSE was 23% in low, 29% in intermediate, and 35% in highly T1 contaminated phantoms. CONCLUSION: dcFSE signal decay edema mapping is feasible in volunteers and patients. DcFSE SDT is superior to T2 ratio for detection of high-grade and diffuse myocardial edema. J. Magn. Reson. Imaging 2016;44:186-193.

Impacts of nicorandil on infarct myocardium in comparison with nitrate: assessed by cardiac magnetic resonance imaging.

In this pilot study, we compared the infarct and edema size in acute myocardial infarction (MI) patients treated by nicorandil with those treated by nitrate, using cardiac magnetic resonance (CMR) imaging. Fifty-two acute MI patients who underwent emergency percutaneous coronary intervention (PCI) were enrolled, and were assigned to receive nicorandil or nitrate at random just before reperfusion. For the assessment of infarct and edema areas, short-axis delayed enhancement (DE) and T2-weight (T2w) CMR images were acquired 6.1 ± 2.4 days after the onset of MI. A significant correlation was observed between the peak creatinine kinase (CK) level and the infarct size on DE CMR (r = 0.62, p < 0.05), as well as the edema size on T2w CMR (r = 0.70, p < 0.05) in patients treated by nicorandil (28 patients). A similar correlation was seen between the peak CK level and the infarct size on DE CMR (r = 0.84, p < 0.05), as well as the edema size on T2w CMR (r = 0.84, p < 0.05) in patients treated by nitrate (24 patients). The maximum CK level was significantly lower in patients treated by nicorandil rather than nitrate (1991 ± 1402, 2785 ± 2121 IU/L, respectively, p = 0.03). Both the edema size on T2w CMR and the infarct size on DE CMR were significantly smaller in patients treated by nicorandil rather than nitrate (17.7 ± 9.9, 21.9 ± 13.7 %; p = 0.03, 10.3 ± 6.0, 12.7 ± 6.9 %, p = 0.03, respectively). The presence and amount of microvascular obstruction were significantly smaller in patients treated by nicorandil rather than nitrate (39.2, 64.7 %; p = 0.03; 2.2 ± 1.3, 3.4 ± 1.5 cm(2); p = 0.02, respectively). Using CMR imaging, we demonstrated that the complementary use of intravenously and intracoronary administered nicorandil during PCI favorably acts more on the damaged myocardium after MI than nitrate. We need a further powered prospective study on the use of nicorandil.

Cardiac Magnetic Resonance Studies in a Large Animal Model That Simulates the Cardiac Abnormalities of Human Septic Shock.

BACKGROUND: Septic shock is associated with increases in end-diastolic volume (EDV) and decreases in ejection fraction that reverse within 10 days. Nonsurvivors do not develop EDV increases. The mechanism is unknown. METHODS AND RESULTS: Purpose-bred beagles (n=33) were randomized to receive intrabronchial Staphylococcus aureus or saline. Over 96 hours, cardiac magnetic resonance imaging and echocardiograms were performed. Tissue was obtained at 66 hours. From 0 to 96 hours after bacterial challenge, septic animals versus controls had significantly increased left ventricular wall edema (6%) and wall thinning with loss of mass (15%). On histology, the major finding was nonocclusive microvascular injury with edema in myocytes, the interstitium, and endothelial cells. Edema was associated with significant worsening of biventricular ejection fractions, ventricular-arterial coupling, and circumferential strain. Early during sepsis, (0-24 hours), the EDV decreased; significantly more in nonsurvivors (ie, greater diastolic dysfunction). From 24 to 48 hours, septic animals' biventricular chamber sizes increased; in survivors significantly greater than baseline and nonsurvivors, whose EDVs were not different from baseline. Preload, afterload, or heart rate differences did not explain these differential changes. CONCLUSIONS: The cardiac dysfunction of sepsis is associated with wall edema. In nonsurvivors, at 0 to 24 hours, sepsis induces a more severe diastolic dysfunction, further decreasing chamber size. The loss of left ventricular mass with wall thinning in septic survivors may, in part, explain the EDV increases from 24 to 48 hours because of a potentially reparative process removing damaged wall tissue. Septic cardiomyopathy is most consistent with a nonocclusive microvascular injury resulting in edema causing reversible systolic and diastolic dysfunction with more severe diastolic dysfunction being associated with a decreased EDV and death.

Takotsubo cardiomyopathy mimicking an apical hypertrophic cardiomyopathy.

A 45-years old woman presented for dyspnea and cardiac chest pain. ECG showed deep T-wave inversion while CMR showed normal ejection fraction, hypertrophy and systolic obliteration of the apex suggesting apical HCM. Myocardial oedema was noted at the apex. Complete regression of hypertrophy and myocardial edema was observed after 2 months, and a final diagnosis of subacute Takotsubo was made.

Diagnostic performance of unenhanced electrocardiogram-gated cardiac CT for detecting myocardial edema.

To assess the diagnostic performance of unenhanced electrocardiogram (ECG)-gated cardiac computed tomography (CT) for detecting myocardial edema, using MRI T2 mapping as the reference standard. This retrospective study protocol was approved by our institutional review board, which waived the requirement for written informed consent. Between December 2017 to February 2019, consecutive patients who had undergone T2 mapping for myocardial tissue characterization were identified. We excluded patients who did not undergo unenhanced ECG-gated cardiac CT within 3 months from MRI T2 mapping or who had poor CT image quality. All patients underwent unenhanced ECG-gated cardiac CT with an axial scan using a third-generation, 320 × 0.5 mm detector-row CT unit. Two radiologists together drew regions of interest (ROIs) in the interventricular septum on the unenhanced ECG-gated cardiac CT images. Using T2 mapping as the reference standard, the diagnostic performance of unenhanced cardiac CT for detecting myocardial edema was evaluated by using the area under the receiver operating characteristic curve with sensitivity and specificity. Youden index was used to find an optimal sensitivity-specificity cutoff point. A cardiovascular radiologist independently performed the measurements, and interobserver reliability was assessed using intraclass correlation coefficients for CT value measurements. A P value of <.05 was considered statistically significant. We included 257 patients who had undergone MRI T2 mapping. Of the 257 patients, 35 patients underwent unenhanced ECG-gated cardiac CT. One patient was excluded from the study because of poor CT image quality. Finally, 34 patients (23 men; age 64.7 ±â€…14.6 years) comprised our study group. Using T2 mapping, we identified myocardial edema in 19 patients. Mean CT and T2 values for 34 patients were 46.3 ±â€…2.7 Hounsfield unit and 49.0 ±â€…4.9 ms, respectively. Mean CT values moderately correlated with mean T2 values (Rho = -0.41; P < .05). Mean CT values provided a sensitivity of 63.2% and a specificity of 93.3% for detecting myocardial edema, with a cutoff value of ≤45.0 Hounsfield unit (area under the receiver operating characteristic curve = 0.77; P < .01). Inter-observer reproducibility in measuring mean CT values was excellent (intraclass correlation coefficient = 0.93; [95% confidence interval: 0.86, 0.96]). Myocardial edema could be detected by CT value of myocardium in unenhanced ECG-gated cardiac CT.