Contrast-enhanced cardiac MRI is superior to non-contrast mapping to predict left ventricular remodeling at 6 months after acute myocardial infarction

OBJECTIVES

Parametric mapping constitutes a novel cardiac magnetic resonance (CMR) technique enabling quantitative assessment of pathologic alterations of left ventricular (LV) myocardium. This study aimed to investigate the clinical utility of mapping techniques with and without contrast agent compared to standard CMR to predict adverse LV remodeling following acute myocardial infarction (AMI).

MATERIALS AND METHODS

A post hoc analysis was performed on sixty-four consecutively enrolled patients (57 ± 12 years, 54 men) with first-time reperfused AMI. Baseline CMR was obtained at 8 ± 5 days post-AMI, and follow-up CMR at 6 ± 1.4 months. T1/T2 mapping, T2-weighted, and late gadolinium enhancement (LGE) acquisitions were performed at baseline and cine imaging was used to determine adverse LV remodeling, defined as end-diastolic volume increase by 20% at 6 months.

RESULTS

A total of 11 (17%) patients developed adverse LV remodeling. At baseline, patients with LV remodeling showed larger edema (30 ± 11 vs. 22 ± 10%LV; p < 0.05), infarct size (24 ± 11 vs. 14 ± 8%LV; p < 0.001), extracellular volume (ECVinfarct; 63 ± 12 vs. 47 ± 11%; p < 0.001), and native T2infarct (95 ± 16 vs. 78 ± 17 ms; p < 0.01). ECVinfarct and infarct size by LGE were the best predictors of LV remodeling with areas under the curve (AUCs) of 0.843 and 0.789, respectively (all p < 0.01). Native T1infarct had the lowest AUC of 0.549 (p = 0.668) and was inferior to edema size by T2-weighted imaging (AUC = 0.720; p < 0.05) and native T2infarct (AUC = 0.766; p < 0.01).

CONCLUSION

In this study, ECVinfarct and infarct size by LGE were the best predictors for the development of LV remodeling within 6 months after AMI, with a better discriminative performance than non-contrast mapping CMR.

CLINICAL RELEVANCE STATEMENT

This study demonstrates the predictive value of contrast-enhanced and non-contrast as well as conventional and novel CMR techniques for the development of LV remodeling following AMI, which might help define precise CMR endpoints in experimental and clinical myocardial infarction trials.

KEY POINTS

• Multiparametric CMR provides insights into left ventricular remodeling at 6 months following an acute myocardial infarction. • Extracellular volume fraction and infarct size are the best predictors for adverse left ventricular remodeling. • Contrast-enhanced T1 mapping has a better predictive performance than non-contrast standard CMR and T1/T2 mapping.

Prognostic Relevance of Ischemic Late Gadolinium Enhancement in Apparently Healthy Endurance Athletes: A Follow-up Study Over 5 years

BACKGROUND

In many cardiac diseases, myocardial scar tissue detected by late gadolinium enhancement (LGE) is a risk factor for cardiac arrhythmia and sudden cardiac death. Previous studies in athletes reported an increased risk for cardiac events in this group of ostensibly healthy subjects. However, the currently available longitudinal studies on this topic included fairly old marathon runners with a mean age of 57 ± 6 years or represent a case-control study in athletes with preexisting ventricular arrhythmia. The purpose of this prospective study was to analyze the prognostic relevance of LGE cardiac magnetic resonance (CMR) in middle-aged endurance athletes without known preexisting cardiac disorders.

METHODS

Three-hundred and twelve apparently healthy athletes were prospectively enrolled. Inclusion criteria were a training for a minimum of 10 h per week and regularly participation in competitions. LGE CMR was obtained at baseline in all athletes and presence of LGE was classified visually according to established criteria as ischemic LGE, major or minor non-ischemic LGE or absent LGE. Follow-up consisted of a standardized questionnaire and an additional phone call in case of incomplete data. An event was defined as fatal myocardial infarction, ventricular tachycardia, ventricular fibrillation or sudden cardiac death (SCD).

RESULTS

Complete follow-up was available for 293/312 athletes (94%) including 145 triathletes, 74 marathon runners and 74 cyclists after a median of 5.6 [quartiles 4,3, 6,4] years. Median age was 44 [35, 50] years at study enrollment. Spiroergometry did not reveal heart rhythm disturbances or significant ECG changes in the study population. LGE CMR revealed myocardial scar/focal fibrosis in 80 of 293 athletes (27%) including 7 athletes (2%) with ischemic subendocardial LGE of the left ventricle (LV), 16 athletes (6%) with major non-ischemic LGE of the LV and 57 athletes (19%) with minor non-ischemic LGE. During follow-up, two athletes experienced SCD. One marathon runner died during a training run and one cyclist died suddenly at rest. Both athletes had ischemic LGE of the LV. The event rate for SCD was 0.7% in the entire study population and 28% in the 7 athletes with ischemic LGE (p < 0.001 compared to athletes without LGE).

CONCLUSIONS

Our findings indicate that athletes with ischemic LGE due to unrecognized myocardial infarction are at increased risk for SCD. Our findings highlight the value of LGE CMR to detect occult ischemic scar in asymptomatic apparently healthy athletes, which is of importance, since current guidelines do not recommend to incorporate routine cardiac imaging in pre-participation screening. Athletes with ischemic myocardial scar should at least consider to refrain from high-level exercise as an individual decision.

Noninvasive evaluation of pulmonary artery stiffness in heart failure patients via cardiovascular magnetic resonance

Heart failure (HF) presents manifestations in both cardiac and vascular abnormalities. Pulmonary hypertension (PH) is prevalent in up 50% of HF patients. While pulmonary arterial hypertension (PAH) is closely associated with pulmonary artery (PA) stiffness, the association of HF caused, post-capillary PH and PA stiffness is unknown. We aimed to assess and compare PA stiffness and blood flow hemodynamics noninvasively across HF entities and control subjects without HF using CMR. We analyzed data of a prospectively conducted study with 74 adults, including 55 patients with HF across the spectrum (20 HF with preserved ejection fraction [HFpEF], 18 HF with mildly-reduced ejection fraction [HFmrEF] and 17 HF with reduced ejection fraction [HFrEF]) as well as 19 control subjects without HF. PA stiffness was defined as reduced vascular compliance, indicated primarily by the relative area change (RAC), altered flow hemodynamics were detected by increased flow velocities, mainly by pulse wave velocity (PWV). Correlations between the variables were explored using correlation and linear regression analysis. PA stiffness was significantly increased in HF patients compared to controls (RAC 30.92 ± 8.47 vs. 50.08 ± 9.08%, p < 0.001). PA blood flow parameters were significantly altered in HF patients (PWV 3.03 ± 0.53 vs. 2.11 ± 0.48, p < 0.001). These results were consistent in all three HF groups (HFrEF, HFmrEF and HFpEF) compared to the control group. Furthermore, PA stiffness was associated with higher NT-proBNP levels and a reduced functional status. PA stiffness can be assessed non-invasively by CMR. PA stiffness is increased in HFrEF, HFmrEF and HFpEF patients when compared to control subjects.Trial registration The study was registered at the German Clinical Trials Register (DRKS, registration number: DRKS00015615).

Long-term cardiotoxicity in germ cell cancer survivors after platinum-based chemotherapy: cardiac MR shows impaired systolic function and tissue alterations

OBJECTIVES

Long-term toxicities of germ cell cancer (GCC) treatment are of particular importance in young men with a life expectancy of several decades after curative treatment. This study aimed to investigate the long-term effects of platinum-based chemotherapy on cardiac function and myocardial tissue in GCC survivors by cardiac magnetic resonance (CMR) imaging.

METHODS

Asymptomatic GCC survivors ≥ 3 years after platinum-based chemotherapy and age-matched healthy controls underwent CMR assessment, including left ventricular (LV) and right ventricular (RV) ejection fraction (EF), strain analysis, late gadolinium enhancement (LGE) imaging, and T1/T2 mapping.

RESULTS

Forty-four survivors (age 44 [interquartile range, IQR 37-52] years; follow-up time 10 [IQR 5-15] years after chemotherapy) and 21 controls were evaluated. LV- and RVEF were lower in GCC survivors compared to controls (LVEF 56 ± 5% vs. 59 ± 5%, p = 0.017; RVEF 50 ± 7% vs. 55 ± 7%, p = 0.008). Seven percent (3/44) of survivors showed reduced LVEF (< 50%), and 41% (18/44) showed borderline LVEF (50-54%). The strain analysis revealed significantly reduced deformation compared to controls (LV global longitudinal strain [GLS] -13 ± 2% vs. -15 ± 1%, p < 0.001; RV GLS -15 ± 4% vs. -19 ± 4%, p = 0.005). Tissue characterization revealed focal myocardial fibrosis in 9 survivors (20%) and lower myocardial native T1 times in survivors compared to controls (1202 ± 25 ms vs. 1226 ± 37 ms, p = 0.016). Attenuated LVEF was observed after two cycles of platinum-based chemotherapy (54 ± 5% vs. 62 ± 5%, p < 0.001).

CONCLUSION

Based on CMR evaluation, combination chemotherapy with cumulative cisplatin ≥ 200 mg/m2 is associated with attenuated biventricular systolic function and myocardial tissue alterations in asymptomatic long-term GCC survivors.

CLINICAL RELEVANCE STATEMENT

Platinum-based chemotherapy is associated with decreased systolic function, non-ischemic focal myocardial scar, and decreased T1 times in asymptomatic long-term germ cell cancer survivors. Clinicians should be particularly aware of the risk of cardiac toxicity after platinum-based chemotherapy.

KEY POINTS

• Platinum-based chemotherapy is associated with attenuation of biventricular systolic function, lower myocardial T1 relaxation times, and non-ischemic late gadolinium enhancement. • Decreased systolic function and non-ischemic late gadolinium enhancement are associated with a cumulative cisplatin dose of  ≥ 200 mg/m2. • Cardiac MRI can help to identify chemotherapy-associated changes in cardiac function and tissue in asymptomatic long-term germ cell cancer survivors.

Left ventricular myocardial strain responding to chronic pressure overload in patients with resistant hypertension evaluated by feature-tracking CMR

OBJECTIVES

The study aimed to investigate the alterations of myocardial deformation responding to long-standing pressure overload and the effects of focal myocardial fibrosis using feature-tracking cardiac magnetic resonance (FT-CMR) in patients with resistant hypertension (RH).

METHODS

Consecutive RH patients were prospectively recruited and underwent CMR at a single institution. FT-CMR analyses based on cine images were applied to measure left ventricular (LV) peak systolic global longitudinal (GLS), radial (GRS), and circumferential strain (GCS). Functional and morphological CMR variables, and late gadolinium enhancement (LGE) imaging were also obtained.

RESULTS

A total of 50 RH patients (63 ± 12 years, 32 men) and 18 normotensive controls (57 ± 8 years, 12 men) were studied. RH patients had a higher average systolic blood pressure than controls (166 ± 21 mmHg vs. 116 ± 8 mmHg, p < 0.001) with the intake of 5 ± 1 antihypertensive drugs. RH patients showed increased LV mass index (78 ± 15 g/m2 vs. 61 ± 9 g/m2, p < 0.001), decreased GLS (- 16 ± 3% vs. - 19 ± 2%, p = 0.001) and GRS (41 ± 12% vs. 48 ± 8%, p = 0.037), and GCS was reduced by trend (- 17 ± 4% vs. - 19 ± 4%, p = 0.078). Twenty-one (42%) RH patients demonstrated a LV focal myocardial fibrosis (LGE +). LGE + RH patients had higher LV mass index (85 ± 14 g/m2 vs. 73 ± 15 g/m2, p = 0.007) and attenuated GRS (37 ± 12% vs. 44 ± 12%, p = 0.048) compared to LGE - RH patients, whereas GLS (p = 0.146) and GCS (p = 0.961) were similar.

CONCLUSION

Attenuation of LV GLS and GRS, and GCS decline by tendency, might be adaptative changes responding to chronic pressure overload. There is a high incidence of focal myocardial fibrosis in RH patients, which is associated with reduced LV GRS.

CLINICAL RELEVANCE STATEMENT

Feature-tracking CMR-derived myocardial strain offers insights into the influence of long-standing pressure overload and of a myocardial fibrotic process on cardiac deformation in patients with resistant hypertension.

KEY POINTS

• Variations of left ventricular strain are attributable to the degree of myocardial impairment in resistant hypertensive patients. • Focal myocardial fibrosis of the left ventricle is associated with attenuated global radial strain. • Feature-tracking CMR provides additional information on the attenuation of myocardial deformation responding to long-standing high blood pressure.

Differentiation of acute non-ST elevation myocardial infarction and acute infarct-like myocarditis by visual pattern analysis: a head-to-head comparison of different cardiac MR techniques

OBJECTIVES

Parametric cardiac magnetic resonance (CMR) techniques have improved the diagnosis of pathologies. However, the primary tool for differentiating non-ST elevation myocardial infarction (NSTEMI) from myocarditis is still a visual assessment of conventional signal-intensity-based images. This study aimed at analyzing the ability of parametric compared to conventional techniques to visually differentiate ischemic from non-ischemic myocardial injury patterns.

METHODS

Twenty NSTEMI patients, twenty infarct-like myocarditis patients, and twenty controls were examined using cine, T2-weighted CMR (T2w) and late gadolinium enhancement (LGE) imaging and T1/T2 mapping on a 1.5 T scanner. CMR images were presented in random order to two experienced fully blinded observers, who had to assign them to three categories by a visual analysis: NSTEMI, myocarditis, or healthy.

RESULTS

The conventional approach (cine, T2w and LGE combined) had the best diagnostic accuracy with 92% (95%CI: 81-97) for NSTEMI and 86% (95%CI: 71-94) for myocarditis. The diagnostic accuracies using T1 maps were 88% (95%CI: 74-95) and 80% (95%CI: 62-91), 84% (95%CI: 67-93) and 74% (95%CI: 54-87) for LGE, and 83% (95%CI: 66-92) and 73% (95%CI: 53-87) for T2w. The accuracies for cine (72% (95%CI: 52-86) and 60% (95%CI: 38-78)) and T2 maps (62% (95%CI: 40-79) and 47% (95%CI: 28-68)) were significantly lower compared to the conventional approach (p < 0.001 and p < 0.0001).

CONCLUSIONS

The conventional approach provided a reliable visual discrimination between NSTEMI, myocarditis, and controls. The diagnostic accuracy of a visual pattern analysis of T1 maps was not significantly inferior, whereas the diagnostic accuracy of T2 maps was not sufficient in this context.

CLINICAL RELEVANCE STATEMENT

The ability of parametric compared to conventional CMR techniques to visually differentiate ischemic from non-ischemic myocardial injury patterns can avoid potentially unnecessary invasive coronary angiography and help to shorten CMR protocols and to reduce the need of gadolinium contrast agents.

KEY POINTS

• A visual differentiation of ischemic from non-ischemic patterns of myocardial injury is reliably achieved by a combination of conventional CMR techniques (cine, T2-weighted and LGE imaging). • There is no significant difference in accuracies between visual pattern analysis on native T1 maps without providing quantitative values and a conventional combined approach for differentiating non-ST elevation myocardial infarction, infarct-like myocarditis, and controls. • T2 maps do not provide a sufficient diagnostic accuracy for visual pattern analysis for differentiating non-ST elevation myocardial infarction, infarct-like myocarditis, and controls.

Genome-wide gene expression responses to experimental manipulation of Saccharomyces cerevisiae repressor activator protein 1 (Rap1) expression level

Precise regulation of transcription in gene expression is critical for all aspects of normal organism form, fitness, and function and even minor alterations in the level, location, and timing of gene expression can result in phenotypic variation within and between species including evolutionary innovations and human disease states. Eukaryotic transcription is regulated by a complex interplay of multiple factors working both at a physical and molecular levels influencing this process. In Saccharomyces cerevisiae, the TF with the greatest number of putative regulatory targets is the essential gene Repressor Activator Protein 1 (RAP1). While much is known about the roles of Rap1 in gene regulation and numerous cellular processes, the response of Rap1 target genes to systematic titration of RAP1 expression level remains unknown. To fill this knowledge gap, we used a strain with a tetracycline-titratable promoter replacing wild-type regulatory sequences of RAP1 to systematically reduce the expression level of RAP1 and followed this with RNA sequencing (RNA-seq) to measure genome-wide gene expression responses. Previous research indicated that Rap1 plays a significant regulatory role in particular groups of genes including telomere-proximal genes, homothallic mating (HM) loci, glycolytic genes, DNA repair genes, and ribosomal protein genes; therefore, we focused our analyses on these groups and downstream targets to determine how they respond to reductions in RAP1 expression level. Overall, despite being known as both an activator and as a repressor of its target genes, we found that Rap1 acts as an activator for more target genes than as a repressor. Additionally, we found that Rap1 functions as an activator of ribosomal protein genes and a repressor of the silent mating locus genes consistent with predictions from the literature. Unexpectedly, we found that Rap1 functions as a repressor of glycolytic enzyme genes contrary to prior reports of it having the opposite effect. We also compared the expression of RAP1 to five different genes related to DNA repair pathway and found that decreasing RAP1 downregulated four of those five genes. Finally, we found no effect of RAP1 depletion on telomere-proximal genes despite its functioning to silence telomeric repeat-containing RNAs. Together our results enrich our understanding of this important transcriptional regulator. The graphical abstract is provided as a supplementary fig. (S-Fig 1).

[Routine computed tomography body composition analysis-experience in intensive care patients]

The assessment of the nutritional status of patients in the intensive care unit is recommended in current guidelines and should include the assessment of muscle status. A suitable method is the analysis of routine computed tomography (CT) scans, which are frequently performed in critically ill patients. With the help of special software, individual CT slices are processed and various parameters such as muscle area, muscle density or even the percentage of adipose tissue are displayed and quantified. It has been shown that cross-sectional acquisition of skeletal muscle in the lumbar spine correlates very well with total body muscle. There are defined, albeit population-based, cut-off values that can be used to establish diagnosis of sarcopenia. Monitoring of individualized nutritional therapy can be accomplished by assessment of repetitive CT examinations. The steadily growing body of data confirms that the method can make a valuable contribution to the assessment of body composition in intensive care medicine. Most of the currently available software requires time-consuming processing of the CT. Automated programs, which are now occasionally available and eliminate the need for most manual processing, may make the method even more attractive in the future. Ultimately, the risk of intensive transport to the CT or radiation exposure may be only justified for medical indications. Nevertheless, whenever CT is available for medical reasons, it should also be exploited for composition analysis.

3 Tesla magnetic resonance imaging in patients with cardiac implantable electronic devices: a single centre experience

AIMS

Three Tesla (T) magnetic resonance imaging (MRI) provides critical imaging information for many conditions. Owing to potential interactions of the magnetic field, it is largely withheld from patients with cardiac implantable electronic devices (CIEDs). Therefore, we assessed the safety of 3T MRI in patients with '3T MRI-conditional' and 'non-3T MRI-conditional' CIEDs.

METHODS AND RESULTS

We performed a retrospective single-centre analysis of clinically indicated 3T MRI examinations in patients with conventional pacemakers, cardiac resynchronization devices, and implanted defibrillators from April 2020 to May 2022. All CIEDs were interrogated and programmed before and after scanning. Adverse events included all-cause death, arrhythmias, loss of capture, inappropriate anti-tachycardia therapies, electrical reset, and lead or generator failure during or shortly after MRI. Changes in signal amplitude and lead impedance were systematically assessed. Statistics included median and interquartile range. A total of 132 MRI examinations were performed on a 3T scanner in 97 patients. Thirty-five examinations were performed in patients with 'non-3T MRI-conditional' CIEDs. Twenty-six scans were performed in pacemaker-dependent patients. No adverse events occurred during or shortly after MRI. P-wave or R-wave reductions ≥ 50 and ≥ 25%, respectively, were noted after three (2.3%) scans, all in patients with '3T MRI-conditional' CIEDs. Pacing and shock impedance changed by ± 30% in one case (0.7%). Battery voltage and stimulation thresholds did not relevantly change after MRI.

CONCLUSION

Pending verification in independent series, our data suggest that clinically indicated MRI scans at 3T field strength should not be withheld from patients with cardiac pacemakers or defibrillators.

[Cardiooncology-usefulness of cardiac MRI : Inflammation, fibrosis, outcome]

BACKGROUND

With rapidly increasing survival chances of cancer patients, the potential side effects of cancer therapeutics are increasingly relevant and a potentially lifelong issue. If cardiotoxic effects are not detected at a reversible stage, this might result in irreversible heart failure.

OBJECTIVES

This article will portray the current state of knowledge on the use of cardiac magnetic resonance imaging (cardiac MRI) in the field of cardio-oncology. The aim is to provide an overview of the advantages of cardiac MRI to determine myocardial function and analyze inflammatory or fibrotic myocardial changes.

MATERIALS AND METHODS

Current studies on this topic were collected and evaluated. Expert recommendations from various position papers were reviewed and summarized. Lastly, an MRI protocol to assess potential cardiotoxic effects of cancer therapeutics was discussed.

RESULTS

Up to 20% of patients are reported to suffer from cancer therapeutics-related cardiac dysfunction (CTRCD). Especially those with cardiovascular risk factors should receive pre- and posttherapeutic monitoring of heart function. Cardiac MRI is currently suggested as an imaging tool to analyze myocardial function if echocardiographic assessment is insufficient. However, cardiac MRI is also an excellent method for additional tissue analysis.

CONCLUSION

Current consensus statements recommend cardiac MRI as optional in cases where echocardiography image quality is not adequate. Nevertheless, patients with reduced heart function on echocardiography might benefit from early assessment of inflammatory or fibrotic changes due to CTRCD using cardiac MRI.

3 Tesla magnetic resonance imaging in patients with cardiac electronic implantable devices: a single center experience

Background

Cardiac magnetic resonance imaging (MRI), a key method guiding medical diagnosis and therapy, is increasingly performed at 3 Tesla (T) field strength. Growing evidence suggests a relatively safe conductance of 1.5 T MRI in patients with cardiac implantable electronic devices (CIEDs), leading to conditional certification of some CIEDs for MRI. However, data on the safety of MRI imaging at 3 T in patients with CIEDs are scarce.

Purpose

We analysed the safety of clinically indicated 3 T MRI in patients with “3T MRI-conditional” and “3 T MRI-non-conditional” CIEDs.

Methods

We performed a retrospective single-center analysis of consecutive patients with CIEDs labelled by the manufacturer as “MRI non-conditional”, “1.5 T MRI-conditional” and “3 T MRI-conditional”. Patients underwent clinically indicated 3 T MRI of different thoracic and non-thoracic body regions from April 2020 to February 2022. Devices were interrogated and programmed appropriately before and after scanning. Statistics included median and interquartile range. Measurements of device and lead function and integrity before and after scanning were assessed. Adverse events included all-cause death, arrhythmias, loss of capture, inappropriate anti-tachycardia therapies, electrical reset and lead or generator failure during or shortly after MRI scan.

Results

One hundred twenty-eight 3 T MRI scans were performed in 94 patients (mean age 72±16 years, 36.2% female). 3T MRI scans were performed in patients with “non-MRI-conditional” devices (n=9), “1.5 T MRI-conditional” devices (n=22), and “3 T MRI-conditional” devices (n=97). Patients were pacemaker-dependent in 24 MRI scans. After MRI, lead impedance had changed by 100 Ohms or more in seven cases (4 atrial and 3 right ventricular leads). P-wave (−25%) reduction was noted in one, R-wave (−50%) reduction in two cases. Right atrial and ventricular threshold exceeded the limit of 0,5V in one case each only in “3 T MRI-conditional” devices. No clinically relevant adverse events occurred.

Conclusion

3 T MRI was safely conducted in patients with “3 T MRI-conditional” and “non-MRI conditional” CIEDs in our single-center study. Pending verification in independent series, our data suggest that clinically indicated 3T MRI scans should not be withheld from patients with cardiac pacemakers or defibrillators.

Funding Acknowledgement

Type of funding sources: None.

Brief Research Report: Quantitative Analysis of Potential Coronary Microvascular Disease in Suspected Long-COVID Syndrome

Background

Case series have reported persistent cardiopulmonary symptoms, often termed long-COVID or post-COVID syndrome, in more than half of patients recovering from Coronavirus Disease 19 (COVID-19). Recently, alterations in microvascular perfusion have been proposed as a possible pathomechanism in long-COVID syndrome. We examined whether microvascular perfusion, measured by quantitative stress perfusion cardiac magnetic resonance (CMR), is impaired in patients with persistent cardiac symptoms post-COVID-19.

Methods

Our population consisted of 33 patients post-COVID-19 examined in Berlin and London, 11 (33%) of which complained of persistent chest pain and 13 (39%) of dyspnea. The scan protocol included standard cardiac imaging and dual-sequence quantitative stress perfusion. Standard parameters were compared to 17 healthy controls from our institution. Quantitative perfusion was compared to published values of healthy controls.

Results

The stress myocardial blood flow (MBF) was significantly lower [31.8 ± 5.1 vs. 37.8 ± 6.0 (μl/g/beat), P < 0.001] and the T2 relaxation time was significantly higher (46.2 ± 3.6 vs. 42.7 ± 2.8 ms, P = 0.002) post-COVID-19 compared to healthy controls. Stress MBF and T1 and T2 relaxation times were not correlated to the COVID-19 severity (Spearman r = −0.302, −0.070, and −0.297, respectively) or the presence of symptoms. The stress MBF showed a U-shaped relation to time from PCR to CMR, no correlation to T1 relaxation time, and a negative correlation to T2 relaxation time (Pearson r = −0.446, P = 0.029).

Conclusion

While we found a significantly reduced microvascular perfusion post-COVID-19 compared to healthy controls, this reduction was not related to symptoms or COVID-19 severity.

COVID-19 vs. Classical Myocarditis Associated Myocardial Injury Evaluated by Cardiac Magnetic Resonance and Endomyocardial Biopsy

Background: Despite the ongoing global pandemic, the impact of COVID-19 on cardiac structure and function is still not completely understood. Myocarditis is a rare but potentially serious complication of other viral infections with variable recovery, and is, in some cases, associated with long-term cardiac remodeling and functional impairment.

Aim: To assess myocardial injury in patients who recently recovered from an acute SARS-CoV-2 infection with advanced cardiac magnetic resonance imaging (CMR) and endomyocardial biopsy (EMB).

Methods: In total, 32 patients with persistent cardiac symptoms after a COVID-19 infection, 22 patients with acute classic myocarditis not related to COVID-19, and 16 healthy volunteers were included in this study and underwent a comprehensive baseline CMR scan. Of these, 10 patients post COVID-19 and 13 with non-COVID-19 myocarditis underwent a follow-up scan. In 10 of the post-COVID-19 and 15 of the non-COVID-19 patients with myocarditis endomyocardial biopsy (EMB) with histological, immunohistological, and molecular analysis was performed.

Results: In total, 10 (31%) patients with COVID-19 showed evidence of myocardial injury, eight (25%) presented with myocardial oedema, eight (25%) exhibited global or regional systolic left ventricular (LV) dysfunction, and nine (28%) exhibited impaired right ventricular (RV) function. However, only three (9%) of COVID-19 patients fulfilled updated CMR–Lake Louise criteria (LLC) for acute myocarditis. Regarding EMB, none of the COVID-19 patients but 87% of the non-COVID-19 patients with myocarditis presented histological findings in keeping with acute or chronic inflammation. COVID-19 patients with severe disease on the WHO scale presented with reduced biventricular longitudinal function, increased RV mass, and longer native T1 times compared with those with only mild or moderate disease.

Conclusions: In our cohort, CMR and EMB findings revealed that SARS-CoV-2 infection was associated with relatively mild but variable cardiac involvement. More symptomatic COVID-19 patients and those with higher clinical care demands were more likely to exhibit chronic inflammation and impaired cardiac function compared to patients with milder forms of the disease.

Loxapine in patient with clozapine-resistant psychosis

Clozapine is recognized as the drug of choice for treatment-refractory schizophrenia, but use may be limited because of strict monitoring requirements and adverse effects including severe neutropenia, seizures, and myocarditis. Loxapine is a first-generation antipsychotic with similarities to clozapine in both structure and receptor binding. This case describes a 57-year-old male with a history of severe paranoid schizophrenia despite treatment with clozapine and other psychotropic agents, who experienced clinical improvement after a cross titration from clozapine to loxapine. Loxapine may be a reasonable alternative in patients with treatment-refractory schizophrenia who do not tolerate or respond to clozapine.

Multi-parametric assessment of left ventricular hypertrophy using late gadolinium enhancement, T1 mapping and strain-encoded cardiovascular magnetic resonance

AIM

To evaluate the ability of single heartbeat fast-strain encoded (SENC) cardiovascular magnetic resonance (CMR) derived myocardial strain to discriminate between different forms of left ventricular (LV) hypertrophy (LVH).

METHODS

314 patients (228 with hypertensive heart disease (HHD), 45 with hypertrophic cardiomyopathy (HCM), 41 with amyloidosis, 22 competitive athletes, and 33 healthy controls) were systematically analysed. LV ejection fraction (LVEF), LV mass index and interventricular septal (IVS) thickness, T1 mapping and atypical late gadolinium enhancement (LGE) were assessed. In addition, the percentage of LV myocardial segments with strain ≤ - 17% (%normal myocardium) was determined.

RESULTS

Patients with amyloidosis and HCM exhibited the highest IVS thickness (17.4 ± 3.3 mm and 17.4 ± 6 mm, respectively, p < 0.05 vs. all other groups), whereas patients with amyloidosis showed the highest LV mass index (95.1 ± 20.1 g/m2, p < 0.05 vs all others) and lower LVEF compared to controls (50.5 ± 9.8% vs 59.2 ± 5.5%, p < 0.05). Analysing subjects with mild to moderate hypertrophy (IVS 11-15 mm), %normal myocardium exhibited excellent and high precision, respectively for the differentiation between athletes vs. HCM (sensitivity and specificity = 100%, Area under the curve; AUC%normalmyocardium = 1.0, 95%CI = 0.85-1.0) and athletes vs. HHD (sensitivity = 83%, specificity = 75%, AUC%normalmyocardium = 0.85, 95%CI = 0.78-0.90). Combining %normal myocardial strain with atypical LGE provided high accuracy also for the differentiation of HHD vs. HCM (sensitivity = 82%, specificity = 100%, AUCcombination = 0.92, 95%CI = 0.88-0.95) and HCM vs. amyloidosis (sensitivity = 83%, specificity = 100%, AUCcombination = 0.83, 95%CI = 0.60-0.96).

CONCLUSION

Fast-SENC derived myocardial strain is a valuable tool for differentiating between athletes vs. HCM and athletes vs. HHD. Combining strain and LGE data is useful for differentiating between HHD vs. HCM and HCM vs. cardiac amyloidosis.

Traveling Volunteers: A Multi-Vendor, Multi-Center Study on Reproducibility and Comparability of 4D Flow Derived Aortic Hemodynamics in Cardiovascular Magnetic Resonance

BACKGROUND

Implementation of four-dimensional flow magnetic resonance (4D Flow MR) in clinical routine requires awareness of confounders.

PURPOSE

To investigate inter-vendor comparability of 4D Flow MR derived aortic hemodynamic parameters, assess scan-rescan repeatability, and intra- and interobserver reproducibility.

STUDY TYPE

Prospective multicenter study.

POPULATION

Fifteen healthy volunteers (age 24.5 ± 5.3 years, 8 females).

FIELD STRENGTH/SEQUENCE

3 T, vendor-provided and clinically used 4D Flow MR sequences of each site.

ASSESSMENT

Forward flow volume, peak velocity, average, and maximum wall shear stress (WSS) were assessed via nine planes (P1-P9) throughout the thoracic aorta by a single observer (AD, 2 years of experience). Inter-vendor comparability as well as scan-rescan, intra- and interobserver reproducibility were examined.

STATISTICAL TESTS

Equivalence was tested setting the 95% confidence interval of intraobserver and scan-rescan difference as the limit of clinical acceptable disagreement. Intraclass correlation coefficient (ICC) and Bland-Altman plots were used for scan-rescan reproducibility and intra- and interobserver agreement. A P-value <0.05 was considered statistically significant. ICCs ≥ 0.75 indicated strong correlation (>0.9: excellent, 0.75-0.9: good).

RESULTS

Ten volunteers finished the complete study successfully. 4D flow derived hemodynamic parameters between scanners of three different vendors are not equivalent exceeding the equivalence range. P3-P9 differed significantly between all three scanners for forward flow (59.1 ± 13.1 mL vs. 68.1 ± 12.0 mL vs. 55.4 ± 13.1 mL), maximum WSS (1842.0 ± 190.5 mPa vs. 1969.5 ± 398.7 mPa vs. 1500.6 ± 247.2 mPa), average WSS (1400.0 ± 149.3 mPa vs. 1322.6 ± 211.8 mPa vs. 1142.0 ± 198.5 mPa), and peak velocity between scanners I vs. III (114.7 ± 12.6 cm/s vs. 101.3 ± 15.6 cm/s). Overall, the plane location at the sinotubular junction (P1) presented most inter-vendor stability (forward: 78.5 ± 15.1 mL vs. 80.3 ± 15.4 mL vs. 79.5 ± 19.9 mL [P = 0.368]; peak: 126.4 ± 16.7 cm/s vs. 119.7 ± 13.6 cm/s vs. 111.2 ± 22.6 cm/s [P = 0.097]). Scan-rescan reproducibility and intra- and interobserver variability were good to excellent (ICC ≥ 0.8) with best agreement for forward flow (ICC ≥ 0.98).

DATA CONCLUSION

The clinical protocol used at three different sites led to differences in hemodynamic parameters assessed by 4D flow.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY STAGE: 2.

Fast Strain-Encoded Cardiac Magnetic Resonance for Diagnostic Classification and Risk Stratification of Heart Failure Patients

OBJECTIVES

The purpose of this study was to compare the ability of fast-strain encoded magnetic resonance (fast-SENC) cardiac magnetic resonance (CMR) to classify and risk stratify all-comer patients with different stages of chronic heart failure (Stages of heart failure A to D) based on American College of Cardiology/American Heart Association guidelines with standard clinical and CMR imaging data.

BACKGROUND

Heart failure is a major cause of morbidity and mortality, resulting in millions of deaths and hospitalizations annually.

METHODS

The study population consisted of 1,169 consecutive patients between September 2017 and February 2019 who underwent CMR for clinical reasons, and 61 healthy volunteers. In addition, clinical follow-up was performed in Stages A and B patients after 1.9 ± 0.4 years. Wall motion score and late gadolinium enhancement score indexes, left ventricular (LV) ejection fraction, and global circumferential and longitudinal strain based on fast-SENC acquisitions, were calculated in all subjects. The percentage of myocardial segments with strain ≤-17% (% normal myocardium) was determined in all subjects.

RESULTS

LV ejection fraction, global circumferential and longitudinal strain, and % normal myocardium significantly decreased with increasing heart failure stages (p < 0.001 for all by analysis of variance). By multivariable analysis, % normal myocardium remained an independent predictor of heart failure stages, exhibiting closer association than LV ejection fraction (rpartial = 0.76 vs. rpartial = 0.30; p < 0.001). Importantly, 149 of 399 (37%) with Stage A were reclassified to Stage B, that is, as having subclinical LV dysfunction based on % normal myocardium <80%. Such patients exhibited significantly higher rates of all-cause mortality and hospital stay due to heart failure during follow-up, compared with patients with % normal myocardium ≥80% (chi-square = 6.9; p = 0.03).

CONCLUSIONS

The % normal myocardium, determined by fast-SENC, enables improved identification of asymptomatic patients with subclinical LV dysfunction compared with LV ejection fraction and risk stratification of patients with so far asymptomatic heart failure. The identification of such presumably healthy patients at high risk for heart failure-related outcomes may bear important medical implications.

Left and right ventricular strain using fast strain-encoded cardiovascular magnetic resonance for the diagnostic classification of patients with chronic non-ischemic heart failure due to dilated, hypertrophic cardiomyopathy or cardiac amyloidosis

AIMS

To compare the ability of left ventricular (LV) and right ventricular (RV) strain measured by fast-strain encoded cardiovascular magnetic resonance (CMR) (fast-SENC) with LV- and RV-ejection fraction for the diagnostic classification of patients with different stages of chronic heart failure (stages A-D based on American College of Cardiology/American Heart Association guidelines) due to non-ischemic cardiomyopathies.

METHODS

Our study population consisted of 276 consecutive patients who underwent CMR for clinical reasons, and 19 healthy subjects. Wall motion score index and non-infarct related late gadolinium enhancement (LGE), LV ejection fraction (LVEF) and RV ejection fraction (RVEF) and global LV- and RV-longitudinal (GLS) and circumferential strain (GCS) based on fast-SENC acquisitions, were calculated in all subjects. The percentage of LV and RV myocardial segments with strain ≤ - 17% (%normal LV and RV myocardium) was determined in all subjects.

RESULTS

LVEF and RVEF, LV-GLS, LV-GCS, RV-GLS, RV-GCS and %normal LV- and RV myocardium depressed with increasing heart failure stage (p < 0.001 for all by ANOVA). By multivariable analysis, %normal LV and RV myocardium exhibited closer associations to heart failure stages than LVEF and RVEF (r_partial = 0.79 versus r_partial = 0.21 for %normal LV myocardium versus LVEF and r_partial = 0.64 versus r_partial = 0.20 for %normal RV myocardium versus RVEF, respectively). Furthermore, %normal LV and RV myocardium exhibited incremental value for the identification of patients (i) with subclinical myocardial dysfunction and (ii) with symptomatic heart failure, surpassing that provided by LVEF and RVEF (ΔAUC = 0.22 for LVEF and ΔAUC = 0.19 for RVEF with subclinical dysfunction, and ΔAUC = 0.19 for LVEF and ΔAUC = 0.22 for RVEF with symptomatic heart failure, respectively, p < 0.001 for all). %normal LV myocardium reclassified 11 of 31 (35%) patients judged as having no structural heart disease by clinical and imaging data to stage B, i.e., subclinical LV-dysfunction.

CONCLUSIONS

In patients with non-ischemic cardiomyopathy, %normal LV and RV myocardium, by fast-SENC, enables improved identification of asymptomatic patients with subclinical LV-dysfunction. This technique may be useful for the early identification of such presumably healthy subjects at risk for heart failure and for monitoring LV and RV deformation during pharmacologic interventions in future studies.

Left and right ventricular strain using fast strain-encoded cardiovascular magnetic resonance for the diagnostic classification of patients with chronic non-ischemic heart failure due to dilated, hypertrophic cardiomyopathy or cardiac amyloidosis

AIMS

To compare the ability of left ventricular (LV) and right ventricular (RV) strain measured by fast-strain encoded cardiovascular magnetic resonance (CMR) (fast-SENC) with LV- and RV-ejection fraction for the diagnostic classification of patients with different stages of chronic heart failure (stages A-D based on American College of Cardiology/American Heart Association guidelines) due to non-ischemic cardiomyopathies.

METHODS

Our study population consisted of 276 consecutive patients who underwent CMR for clinical reasons, and 19 healthy subjects. Wall motion score index and non-infarct related late gadolinium enhancement (LGE), LV ejection fraction (LVEF) and RV ejection fraction (RVEF) and global LV- and RV-longitudinal (GLS) and circumferential strain (GCS) based on fast-SENC acquisitions, were calculated in all subjects. The percentage of LV and RV myocardial segments with strain ≤ - 17% (%normal LV and RV myocardium) was determined in all subjects.

RESULTS

LVEF and RVEF, LV-GLS, LV-GCS, RV-GLS, RV-GCS and %normal LV- and RV myocardium depressed with increasing heart failure stage (p < 0.001 for all by ANOVA). By multivariable analysis, %normal LV and RV myocardium exhibited closer associations to heart failure stages than LVEF and RVEF (rpartial = 0.79 versus rpartial = 0.21 for %normal LV myocardium versus LVEF and rpartial = 0.64 versus rpartial = 0.20 for %normal RV myocardium versus RVEF, respectively). Furthermore, %normal LV and RV myocardium exhibited incremental value for the identification of patients (i) with subclinical myocardial dysfunction and (ii) with symptomatic heart failure, surpassing that provided by LVEF and RVEF (ΔAUC = 0.22 for LVEF and ΔAUC = 0.19 for RVEF with subclinical dysfunction, and ΔAUC = 0.19 for LVEF and ΔAUC = 0.22 for RVEF with symptomatic heart failure, respectively, p < 0.001 for all). %normal LV myocardium reclassified 11 of 31 (35%) patients judged as having no structural heart disease by clinical and imaging data to stage B, i.e., subclinical LV-dysfunction.

CONCLUSIONS

In patients with non-ischemic cardiomyopathy, %normal LV and RV myocardium, by fast-SENC, enables improved identification of asymptomatic patients with subclinical LV-dysfunction. This technique may be useful for the early identification of such presumably healthy subjects at risk for heart failure and for monitoring LV and RV deformation during pharmacologic interventions in future studies.

Cardiovascular magnetic resonance deformation imaging: method comparison and considerations regarding reproducibility

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): German Centre for Cardiovascular Research

Purpose

Myocardial Feature-Tracking (FT) deformation imaging is superior for risk-stratification compared to volumetric approaches. Since there is no clear recommendation regarding FT post-processing, we compared different FT-strain analyses with reference standard techniques, including tagging and strain encoded (SENC) magnetic resonance imaging.

Methods

FT software from 4 different vendors (TomTec/Medis/Circle(CVI)/Neosoft), tagging (Segment), and fastSENC (MyoStrain) were used to determine left ventricular global circumferential and longitudinal strains (GCS/GLS) in 12 healthy volunteers and 12 heart failure patients. Variability and agreements were assessed using intraclass correlation coefficients for absolute agreement (ICCa) and consistency (ICCc) as well as pearson correlation coefficients.

Results

For FT-GCS, consistency was excellent comparing different FT-vendors (ICCc = 0.84-0.97, r = 0.86-0.95) and compared to fSENC (ICCc = 0.78-0.89, r = 0.73-0.81). FT-GCS consistency was excellent compared to tagging (ICCc = 0.79-0.85, r = 0.74-0.77) except for TomTec (ICCc = 0.68, r = 0.72). Absolute FT-GCS agreements between FT-vendors were highest for CVI and Medis (ICCa = 0.96) and lowest for TomTec and Neosoft (ICCa = 0.32). Similarly, absolute FT-GCS agreements were excellent for CVI and Medis compared to both tagging and fSENC (ICCa = 0.84-0.88), good to excellent for Neosoft (ICCa = 0.77 and 0.64) and lowest for TomTec (ICCa = 0.41 and 0.47).

For FT-GLS, consistency was excellent (ICCc≥0.86, r≥0.76). Absolute agreements between FT-vendors were excellent (ICCa = 0.91-0.93) or good to excellent for TomTec (ICCa = 0.69-0.85). Absolute agreements (ICCa) were good (CVI 0.70, Medis 0.60) and fair (TomTec 0.41, Neosoft 0.59) compared to tagging but excellent compared to fSENC (ICCa = 0.77-0.90).

Conclusion

Although absolute agreements differ depending on deformation assessment approaches, consistency and correlation are consistently high irrespective of the method chosen, thus indicating reliable strain assessment. Further standardisation and introduction of uniform references is warranted for routine clinical implementation.

Performance of different myocardial tissue tracking algorithms and acquisition-based strain imaging to characterise myocardial pathology

Background

Myocardial deformation imaging is superior in risk-stratification compared to volumetric approaches. Myocardial Feature-Tracking (FT) allows easy post-processing of routinely acquired cine images. Since there is no clear recommendation regarding FT post-processing we sought to compare different FT-strains with reference standard techniques including tagging and strain encoded (SENC) magnetic resonance imaging.

Methods

CMR-FT software from 4 different vendors (TomTec, Medis, Circle, Neosoft), CMR tagging (Segment) and fastSENC (MyoStrain) were used to determine left ventricular (LV) global longitudinal and circumferential strains (GLS and GCS) in 12 healthy volunteers and 12 heart failure patients. Variability and agreements were assessed using intraclass correlation coefficients, coefficients of variation and Bland Altman plots.

Results

Compared to tagging, FT-based strain was software independently significantly higher except for GCS using Medis (p=0.178). Compared to fSENC, mean-differences of GLS were smaller within a range of ±1.5%. For GCS this only applied to CVI and Medis (&lt;1.5%) but not TomTec (&gt;7%) or Neosoft (&gt;4%). Absolute agreements comparing FT to tagging were best for CVI (GLS ICC0.70) and Medis (GCS ICC0.85). Compared to fSENC agreement of GLS was generally excellent (ICC&gt;0.77), but only CVI and Medis revealed excellent agreement for GCS (ICC0.88 and 0.85). Consistency and correlation of GLS were software independently high compared with tagging and fSENC (ICC&gt;0.86, r&gt;0.76) while being lower for GCS (ICC&gt;0.68, r&gt;0.72).

Conclusion

Although agreement differs between deformation assessment approaches, consistency and correlation are high irrespective of the method chosen, thus indicating reliable strain assessment. Further standardisation and introduction of uniform references is warranted for clinical routine implementation.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): DZHK - German Centre for Cardiovascular Research

Head-to-head comparison of cardiovascular MR feature tracking cine versus acquisition-based deformation strain imaging using myocardial tagging and strain encoding

PURPOSE

Myocardial feature-tracking (FT) deformation imaging is superior for risk stratification compared with volumetric approaches. Because there is no clear recommendation regarding FT postprocessing, we compared different FT-strain analyses with reference standard techniques, including tagging and strain-encoded (SENC) MRI.

METHODS

Feature-tracking software from four different vendors (TomTec, Medis, Circle [CVI], and Neosoft), tagging (Segment), and fastSENC (MyoStrain) were used to determine left ventricular global circumferential strains (GCS) and longitudinal strains (GLS) in 12 healthy volunteers and 12 patients with heart failure. Variability and agreements were assessed using intraclass correlation coefficients for absolute agreement (ICCa) and consistency (ICCc) as well as Pearson correlation coefficients.

RESULTS

For FT-GCS, consistency was excellent comparing different FT vendors (ICCc = 0.84-0.97, r = 0.86-0.95) and in comparison to fast SENC (ICCc = 0.78-0.89, r = 0.73-0.81). FT-GCS consistency was excellent compared with tagging (ICCc = 0.79-0.85, r = 0.74-0.77) except for TomTec (ICCc = 0.68, r = 0.72). Absolute FT-GCS agreements among FT vendors were highest for CVI and Medis (ICCa = 0.96) and lowest for TomTec and Neosoft (ICCa = 0.32). Similarly, absolute FT-GCS agreements were excellent for CVI and Medis compared with both tagging and fast SENC (ICCa = 0.84-0.88), good to excellent for Neosoft (ICCa = 0.77 and 0.64), and lowest for TomTec (ICCa = 0.41 and 0.47). For FT-GLS, consistency was excellent (ICCc ≥ 0.86, r ≥ 0.76). Absolute agreements among FT vendors were excellent (ICCa = 0.91-0.93) or good to excellent for TomTec (ICCa = 0.69-0.85). Absolute agreements (ICCa) were good (CVI 0.70, Medis 0.60) and fair (TomTec 0.41, Neosoft 0.59) compared with tagging, but excellent compared with fast SENC (ICCa = 0.77-0.90).

CONCLUSION

Although absolute agreements differ depending on deformation assessment approaches, consistency and correlation are consistently high regardless of the method chosen, thus indicating reliable strain assessment. Further standardisation and introduction of uniform references is warranted for routine clinical implementation.

Myocardial strain analysis of the right ventricle: comparison of different cardiovascular magnetic resonance and echocardiographic techniques

BACKGROUND

Right ventricular (RV) strain is a useful predictor of prognosis in various cardiovascular diseases, including those traditionally believed to impact only the left ventricle. We aimed to determine inter-modality and inter-technique agreement in RV longitudinal strain (LS) measurements between currently available cardiovascular magnetic resonance (CMR) and echocardiographic techniques, as well as their reproducibility and the impact of layer-specific strain measurements.

METHODS

RV-LS was determined in 62 patients using 2D speckle tracking echocardiography (STE, Epsilon) and two CMR techniques: feature tracking (FT) and strain-encoding (SENC), and in 17 healthy subjects using FT and SENC only. Measurements included global and free-wall LS (GLS, FWLS). Inter-technique agreement was assessed using linear regression and Bland-Altman analysis. Reproducibility was quantified using intraclass correlation (ICC) and coefficients of variation (CoV).

RESULTS

We found similar moderate agreement between both CMR techniques and STE in patients: r = 0.57-0.63 for SENC; r = 0.50-0.62 for FT. The correlation between SENC and STE was better for GLS (r = 0.63) than for FWLS (r = 0.57). Conversely, the correlation between FT and STE was higher for FWLS (r = 0.60-0.62) than GLS (r = 0.50-0.54). FT-midmyocardial strain correlated better with SENC and STE than FT-subendocardial strain. The agreement between SENC and FT was fair (r = 0.36-0.41, bias: - 6.4 to - 10.4%) in the entire study group. All techniques except FT showed excellent reproducibility (ICC: 0.62-0.96, CoV: 0.04-0.30).

CONCLUSIONS

We found only moderate inter-modality agreement with STE in RV-LS for both FT and SENC and poor agreement when comparing between the CMR techniques. Different modalities and techniques should not be used interchangeably to determine and monitor RV strain.

A multi-vendor, multi-center study on reproducibility and comparability of fast strain-encoded cardiovascular magnetic resonance imaging

Myocardial strain is a convenient parameter to quantify left ventricular (LV) function. Fast strain-encoding (fSENC) enables the acquisition of cardiovascular magnetic resonance images for strain-measurement within a few heartbeats during free-breathing. It is necessary to analyze inter-vendor agreement of techniques to determine strain, such as fSENC, in order to compare existing studies and plan multi-center studies. Therefore, the aim of this study was to investigate inter-vendor agreement and test-retest reproducibility of fSENC for three major MRI-vendors. fSENC-images were acquired three times in the same group of 15 healthy volunteers using 3 Tesla scanners from three different vendors: at the German Heart Institute Berlin, the Charité University Medicine Berlin-Campus Buch and the Theresien-Hospital Mannheim. Volunteers were scanned using the same imaging protocol composed of two fSENC-acquisitions, a 15-min break and another two fSENC-acquisitions. LV global longitudinal and circumferential strain (GLS, GCS) were analyzed by a trained observer (Myostrain 5.0, Myocardial Solutions) and for nine volunteers repeatedly by another observer. Inter-vendor agreement was determined using Bland-Altman analysis. Test-retest reproducibility and intra- and inter-observer reproducibility were analyzed using intraclass correlation coefficient (ICC) and coefficients of variation (CoV). Inter-vendor agreement between all three sites was good for GLS and GCS, with biases of 0.01–1.88%. Test-retest reproducibility of scans before and after the break was high, shown by ICC- and CoV values of 0.63–0.97 and 3–9% for GLS and 0.69–0.82 and 4–7% for GCS, respectively. Intra- and inter-observer reproducibility were excellent for both parameters (ICC of 0.77–0.99, CoV of 2–5%). This trial demonstrates good inter-vendor agreement and test–retest reproducibility of GLS and GCS measurements, acquired at three different scanners from three different vendors using fSENC. The results indicate that it is necessary to account for a possible bias (< 2%) when comparing strain measurements of different scanners. Technical differences between scanners, which impact inter-vendor agreement, should be further analyzed and minimized.

DRKS Registration Number: 00013253.

Universal Trial Number (UTN): U1111-1207-5874.

Comparison of feature tracking, fast-SENC, and myocardial tagging for global and segmental left ventricular strain

AIMS

A multitude of cardiac magnetic resonance (CMR) techniques are used for myocardial strain assessment; however, studies comparing them are limited. We sought to compare global longitudinal (GLS), circumferential (GCS), segmental longitudinal (SLS), and segmental circumferential (SCS) strain values, as well as reproducibility between CMR feature tracking (FT), tagging (TAG), and fast-strain-encoded (fast-SENC) CMR techniques.

METHODS AND RESULTS

Eighteen subjects (11 healthy volunteers and seven patients with heart failure) underwent two CMR scans (1.5T, Philips) with identical parameters. Global and segmental strain values were measured using FT (Medis), TAG (Medviso), and fast-SENC (Myocardial Solutions). Friedman's test, linear regression, Pearson's correlation coefficient, and Bland-Altman analyses were used to assess differences and correlation in measured GLS and GCS between the techniques. Two-way mixed intra-class correlation coefficient (ICC), coefficient of variance (COV), and Bland-Altman analysis were used for reproducibility assessment. All techniques correlated closely for GLS (Pearson's r: 0.86-0.92) and GCS (Pearson's r: 0.85-0.94). Intra-observer and inter-observer reproducibility was excellent in all techniques for both GLS (ICC 0.92-0.99, CoV 2.6-10.1%) and GCS (ICC 0.89-0.99, CoV 4.3-10.1%). Inter-study reproducibility was similar for all techniques for GLS (ICC 0.91-0.96, CoV 9.1-10.8%) and GCS (ICC 0.95-0.97, CoV 7.6-10.4%). Combined segmental intra-observer reproducibility was good in all techniques for SLS (ICC 0.914-0.953, CoV 12.35-24.73%) and SCS (ICC 0.885-0.978, CoV 10.76-19.66%). Combined inter-study SLS reproducibility was the worst in FT (ICC 0.329, CoV 42.99%), while fast-SENC performed the best (ICC 0.844, CoV 21.92%). TAG had the best reproducibility for combined inter-study SCS (ICC 0.902, CoV 19.08%), while FT performed the worst (ICC 0.766, CoV 32.35%). Bland-Altman analysis revealed considerable inter-technique biases for GLS (FT vs. fast-SENC 3.71%; FT vs. TAG 8.35%; and TAG vs. fast-SENC 4.54%) and GCS (FT vs. fast-SENC 2.15%; FT vs. TAG 6.92%; and TAG vs. fast-SENC 2.15%). Limits of agreement for GLS ranged from ±3.1 (TAG vs. fast-SENC) to ±4.85 (FT vs. TAG) for GLS and ±2.98 (TAG vs. fast-SENC) to ±5.85 (FT vs. TAG) for GCS.

CONCLUSIONS

We found significant differences in measured GLS and GCS between FT, TAG, and fast-SENC. Global strain reproducibility was excellent for all techniques. Acquisition-based techniques had better reproducibility than FT for segmental strain.

Assessment of Global Longitudinal and Circumferential Strain Using Computed Tomography Feature Tracking: Intra-Individual Comparison with CMR Feature Tracking and Myocardial Tagging in Patients with Severe Aortic Stenosis

In this study, we used a single commercially available software solution to assess global longitudinal (GLS) and global circumferential strain (GCS) using cardiac computed tomography (CT) and cardiac magnetic resonance (CMR) feature tracking (FT). We compared agreement and reproducibility between these two methods and the reference standard, CMR tagging (TAG). Twenty-seven patients with severe aortic stenosis underwent CMR and cardiac CT examinations. FT analysis was performed using Medis suite version 3.0 (Leiden, The Netherlands) software. Segment (Medviso) software was used for GCS assessment from tagged images. There was a trend towards the underestimation of GLS by CT-FT when compared to CMR-FT (19.4 ± 5.04 vs. 22.40 ± 5.69, respectively; p = 0.065). GCS values between TAG, CT-FT, and CMR-FT were similar (p = 0.233). CMR-FT and CT-FT correlated closely for GLS (r = 0.686, p < 0.001) and GCS (r = 0.707, p < 0.001), while both of these methods correlated moderately with TAG for GCS (r = 0.479, p < 0.001 for CMR-FT vs. TAG; r = 0.548 for CT-FT vs. TAG). Intraobserver and interobserver agreement was excellent in all techniques. Our findings show that, in elderly patients with severe aortic stenosis (AS), the FT algorithm performs equally well in CMR and cardiac CT datasets for the assessment of GLS and GCS, both in terms of reproducibility and agreement with the gold standard, TAG.

Renal Outcomes of Liver Transplantation Recipients Receiving Standard Immunosuppression and Early Renal Sparing Immunosuppression: A Retrospective Single Center Study

New-onset stage 4-5 chronic kidney disease (CKD) after liver transplantation (LT) is associated with high morbidity, mortality, and economic burden. In 2010, we instituted an early renal sparing immunosuppression (RSI) protocol for LT recipients with severe renal dysfunction (pre-LT dialysis/estimated glomerular filtration rate (eGFR)<30mL/min/1.73 m2 or post-LT acute kidney injury) consisting of 2 doses of basiliximab for induction and delaying tacrolimus to post-LT day 4-7. We examined the effect of early RSI on post-LT renal outcomes.

METHODS

Data on all adults who had LT between January 1, 2010, and December 12, 2014 were collected. We calculated the renal risk index (RRI) score for each LT recipient (https://rri.med.umich.edu). Primary outcome was new-onset post-LT stage 4-5 CKD.

RESULTS

Of 214 LT recipients, 121 (57%) received early RSI and 93 (43%) received standard immunosuppression. Cumulative incidence of new-onset stage 4-5 CKD was higher in early RSI compared with standard immunosuppression (P = 0.03). Female sex and RRI score were the significant risk factors for development of post-LT stage CKD in the entire study cohort as well as the LT recipients with RRI ≥ sixth decile (high-risk group).

CONCLUSIONS

Delaying tacrolimus initiation combined with basiliximab induction did not have a durable effect on long-term renal outcomes in high-risk LT recipients. Further studies are needed to identify the effective strategies to preserve renal function by targeting patients at high risk for CKD progression.

Echocardiography and cardiovascular magnetic resonance based evaluation of myocardial strain and relationship with late gadolinium enhancement

OBJECTIVES

We sought to: (1) determine the agreement in cardiovascular magnetic resonance (CMR) and speckle tracking echocardiography (STE) derived strain measurements, (2) compare their reproducibility, (3) determine which approach is best related to CMR late gadolinium enhancement (LGE).

BACKGROUND

While STE-derived strain is routinely used to assess left ventricular (LV) function, CMR strain measurements are not yet standardized. Strain can be measured using dedicated pulse sequences (strain-encoding, SENC), or post-processing of cine images (feature tracking, FT). It is unclear whether these measurements are interchangeable, and whether strain can be used as an alternative to LGE.

METHODS

Fifty patients underwent 2D echocardiography and 1.5 T CMR. Global longitudinal strain (GLS) was measured by STE (Epsilon), FT (NeoSoft) and SENC (Myocardial Solutions) and circumferential strain (GCS) by FT and SENC.

RESULTS

GLS showed good inter-modality agreement (r-values: 0.71-0.75), small biases (< 1%) but considerable limits of agreement (- 7 to 8%). The agreement between the CMR techniques was better for GLS than GCS (r = 0.81 vs 0.67; smaller bias). Repeated measurements showed low intra- and inter-observer variability for both GLS and GCS (intraclass correlations 0.86-0.99; coefficients of variation 3-13%). LGE was present in 22 (44%) of patients. Both SENC- and FT-derived GLS and GCS were associated with LGE, while STE-GLS was not. Irrespective of CMR technique, this association was stronger for GCS (AUC 0.77-0.78) than GLS (AUC 0.67-0.72) and STE-GLS (AUC = 0.58).

CONCLUSION

There is good inter-technique agreement in strain measurements, which were highly reproducible, irrespective of modality or analysis technique. GCS may better reflect the presence of underlying LGE than GLS.

Strain-encoded cardiac magnetic resonance imaging: a new approach for fast estimation of left ventricular function

Background

Recently introduced fast strain-encoded (SENC) cardiac magnetic resonance (CMR) imaging (fast-SENC) provides real-time acquisition of myocardial performance in a single heartbeat. We aimed to test the ability and accuracy of real-time strain-encoded CMR imaging to estimate left ventricular volumes, ejection fraction and mass.

Methods

Thirty-five subjects (12 healthy volunteers and 23 patients with known or suspected coronary artery disease) were investigated. All study participants were imaged at 1.5 Tesla MRI scanner (Achieva, Philips) using an advanced CMR study protocol which included conventional cine and fast-SENC imaging. A newly developed real-time free-breathing SENC imaging technique based on the acquisition of two images with different frequency modulation was employed.

Results

All parameters were successfully derived from fast-SENC images with total study time of 105 s (a 15 s scan time and a 90 s post-processing time). There was no significant difference between fast-SENC and cine imaging in the estimation of LV volumes and EF, whereas fast-SENC underestimated LV end-diastolic mass by 7%.

Conclusion

The single heartbeat fast-SENC technique can be used as a good alternative to cine imaging for the precise calculation of LV volumes and ejection fraction while the technique significantly underestimates LV end-diastolic mass.