Application Of CMR Research Articles

A novel framework with automated horizontal pleiotropy adjustment in mendelian randomization

The presence of horizontal pleiotropy in Mendelian randomization (MR) analysis has long been a concern due to its potential to induce substantial bias. In recent years, many robust MR methods have been proposed to address this by relaxing the ‘no horizontal pleiotropy’ assumption. Here, we propose a novel two-stage framework called CMR, which integrates a conditional analysis of multiple genetic variants to remove pleiotropy induced by linkage disequilibrium, followed by the application of robust MR methods to model the conditional genetic effect estimates. We demonstrate how the conditional analysis can reduce horizontal pleiotropy and improve the performance of existing MR methods. Extensive simulation studies covering a wide range of scenarios of horizontal pleiotropy showcased the superior performance of the proposed CMR framework over the standard MR framework in which marginal genetic effects are modeled. Moreover, the application of CMR in a negative control outcome analysis and investigation into the causal role of body mass index across various diseases highlighted its potential to deliver more reliable results in real-world applications.

Importance of Cardiovascular Magnetic Resonance Applied to Congenital Heart Diseases in Pediatric Age: A Narrative Review.

Congenital heart diseases (CHDs) represent a heterogeneous group of congenital defects, with high prevalence worldwide. Non-invasive imaging is essential to guide medical and surgical planning, to follow the patient over time in the evolution of the disease, and to reveal potential complications of the chosen treatment. The application of cardiac magnetic resonance imaging (CMRI) in this population allows for obtaining detailed information on the defects without the necessity of ionizing radiations. This review emphasizes the central role of CMR in the overall assessment of CHDs, considering also the limitations and challenges of this imaging technique. CMR, with the application of two-dimensional (2D) and tri-dimensional (3D) steady-state free precession (SSFP), permits the obtaining of very detailed and accurate images about the cardiac anatomy, global function, and volumes' chambers, giving essential information in the intervention planning and optimal awareness of the postoperative anatomy. Nevertheless, CMR supplies tissue characterization, identifying the presence of fat, fibrosis, or oedema in the myocardial tissue. Using a contrast agent for angiography sequences or 2D/four-dimensional (4D) flows offers information about the vascular, valvular blood flow, and, in general, the cardiovascular system hemodynamics. Furthermore, 3D SSFP CMR acquisitions allow the identification of coronary artery abnormalities as an alternative to invasive angiography and cardiovascular computed tomography (CCT). However, CMR requires expertise in CHDs, and it can be contraindicated in patients with non-conditional devices. Furthermore, its relatively longer acquisition time and the necessity of breath-holding may limit its use, particularly in children under eight years old, sometimes requiring anesthesia. The purpose of this review is to elucidate the application of CMR during the pediatric age.

Two-center validation of Pilot Tone based cardiac triggering of a comprehensive cardiovascular magnetic resonance examination.

The electrocardiogram (ECG) signal is prone to distortions from gradient and radiofrequency interference and the magnetohydrodynamic effect during cardiovascular magnetic resonance imaging (CMR). Although Pilot Tone Cardiac (PTC) triggering has the potential to overcome these limitations, effectiveness across various CMR techniques has yet to be established. To evaluate the performance of PTC triggering in a comprehensive CMR exam. Fifteen volunteers and 20 patients were recruited at two centers. ECG triggered images were collected for comparison in a subset of sequences. The PTC trigger accuracy was evaluated against ECG in cine acquisitions. Two experienced readers scored image quality in PTC-triggered cine, late gadolinium enhancement (LGE), and T1- and T2-weighted dark-blood turbo spin echo (DB-TSE) images. Quantitative cardiac function, flow, and parametric mapping values obtained using PTC and ECG triggered sequences were compared. Breath-held segmented cine used for trigger timing analysis was collected in 15 volunteers and 14 patients. PTC calibration failed in three volunteers and one patient; ECG trigger recording failed in one patient. Out of 1987 total heartbeats, three mismatched trigger PTC-ECG pairs were found. Image quality scores showed no significant difference between PTC and ECG triggering. There was no significant difference found in quantitative measurements in volunteers. In patients, the only significant difference was found in post-contrast T1 (p = 0.04). ICC showed moderate to excellent agreement in all measurements. PTC performance was equivalent to ECG in terms of triggering consistency, image quality, and quantitative image measurements across multiple CMR applications.

Comparison of cine cardiac magnetic resonance and echocardiography derived diameters of the aortic root in a large population-based cohort

Transthoracic echocardiography (TTE) and cine cardiac magnetic resonance imaging (CMR) are established imaging methods of the aortic root. We aimed to evaluate the comparability of measurements in TTE and standard cine CMR sequences of the aortic root. Our study included 741 subjects (mean age 63.5 ± 8 years, 43.7% female) from the Hamburg City Health Study (HCHS). Subjects underwent CMR and TTE. Aortic root measurements were performed at the level of the aortic annulus (AoAn), sinus of Valsalva (SoV), and sinotubular junction (STJ) by standard cine CMR in left ventricular long axis and left ventricular outflow tract view. Measurements were performed applying the leading-edge to leading-edge (LL) convention and inner-edge to inner-edge (II) convention in TTE and the II convention in CMR. Inter correlation coefficients (ICCs) demonstrated high inter- and intraobserver reproducibility for CMR and TTE measurements of SoV and STJ (ICCs 0.9–0.98) and moderate reproducibility for AoAn (ICCs 0.68–0.91). CMR measurements of SoV and STJ showed strong agreement with TTE: while correlations were comparable (r = 0.75–0.85) bias was lower with TTE II (bias − 0.1 to − 0.74) versus TTE LL measurements (mean bias − 1.49 to − 2.58 mm). The agreement for AoAn was fair (r = 0.51–0.57) with variable bias (mean bias 0.39–3.9). Standard cine CMR and TTE derived aortic root measurements are reproducible and comparable with higher agreement for TTE II instead of LL measurements. These results support an interchangeable application of TTE and standard CMR for screening of aortic root diseases thereby possibly reducing redundant multimodality imaging.

Bi-ventricular assessment with cardiovascular magnetic resonance at 5 Tesla: A pilot study.

BackgroundCardiovascular magnetic resonance (CMR) imaging at ultra-high fields (UHF) such as 7T has encountered many challenges such as faster T relaxation, stronger B0 and B1+ field inhomogeneities and additional safety concerns due to increased specific absorption rate (SAR) and peripheral nervous stimulation (PNS). Recently, a new line of 5T whole body MRI system has become available, and this study aims at evaluating the performance and benefits of this new UHF system for CMR imaging.MethodsGradient echo (GRE) CINE imaging was performed on healthy volunteers at both 5 and 3T, and was compared to balanced steady-state-free-procession (bSSFP) CINE imaging at 3T as reference. Higher spatial resolution GRE CINE scans were additionally performed at 5T. All scans at both fields were performed with ECG-gating and breath-holding. Image quality was blindly evaluated by two radiologists, and the cardiac functional parameters (e.g., EDV/ESV/mass/EF) of the left and right ventricles were measured for statistical analyses using the Wilcoxon signed-rank test and Bland-Altman analysis.ResultsCompared to 3T GRE CINE imaging, 5T GRE CINE imaging achieved comparable or improved image quality with significantly superior SNR and CNR, and it has also demonstrated excellent capability for high resolution (1.0 × 1.0 × 6.0 mm3) imaging. Functional assessments from 5T GRE CINE images were highly similar with the 3T bSSFP CINE reference.ConclusionsThis pilot study has presented the initial evaluation of CMR CINE imaging at 5T UHF, which yielded superior image quality and accurate functional quantification when compared to 3T counterparts. Along with reliable ECG gating, the new 5T UHF system has the potential to achieve well-balanced performance for CMR applications.

The Role of Cardiovascular Magnetic Resonance Imaging in the Evaluation of Hypertrophic Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disorder, affecting 1 out of 500 adults globally. It is a widely heterogeneous disorder characterized by a range of phenotypic expressions, and is most often identified by non-invasive imaging that includes echocardiography and cardiovascular magnetic resonance imaging (CMR). Within the last two decades, cardiac magnetic resonance imaging (MRI) has emerged as the defining tool for the characterization and prognostication of cardiomyopathies. With a higher image quality, spatial resolution, and the identification of morphological variants of HCM, CMR has become the gold standard imaging modality in the assessment of HCM. Moreover, it has been crucial in its management, as well as adding prognostic information that clinical history nor other imaging modalities may not provide. This literature review addresses the role and current applications of CMR, its capacity in evaluating HCM, and its limitations.

Evidence and Applicability of Stress Cardiovascular Magnetic Resonance in Detecting Coronary Artery Disease: State of the Art.

Cardiovascular magnetic resonance is increasingly used in clinical practice, as it has emerged over the years as an invaluable imaging technique for diagnosis and prognosis, with clear-cut applications in managing patients with both ischemic and non-ischemic heart disease. In this review, we focus on the evidence and clinical application of stress CMR in coronary artery disease from diagnosis to prognosis.

Cardiac magnetic resonance imaging: insights into developmental programming and its consequences for aging.

Cardiovascular diseases (CVD) are important consequences of adverse perinatal conditions such as fetal hypoxia and maternal malnutrition. Cardiac magnetic resonance imaging (CMR) can produce a wealth of physiological information related to the development of the heart. This review outlines the current state of CMR technologies and describes the physiological biomarkers that can be measured. These phenotypes include impaired ventricular and atrial function, maladaptive ventricular remodeling, and the proliferation of myocardial steatosis and fibrosis. The discussion outlines the applications of CMR to understanding the developmental pathways leading to impaired cardiac function. The use of CMR, both in animal models of developmental programming and in human studies, is described. Specific examples are given in a baboon model of intrauterine growth restriction (IUGR). CMR offers great potential as a tool for understanding the sequence of dysfunctional adaptations of developmental origin that can affect the human cardiovascular system.

Letter to the editor: is it time for imaging to level with pathology?

CMR provides pathology-like insights of myocardial abnormality, such as hyperemia, edema, necrosis and fibrosis, which is in-vivo, non-invasive and real-time. Hence, it is most likely to become one alternative tool for mimicking pathology, so-called pathologicalized imaging due to its extraordinary tissue characteristics. This article aims to call for a wider clinical application of CMR with more attention on its tissue characterization value.

Contemporary Application of Cardiovascular Magnetic Resonance Imaging.

Cardiovascular magnetic resonance imaging (CMR) is a comprehensive and versatile diagnostic and prognostic imaging modality that plays an increasingly important role in management of patients with cardiovascular disease. In this review, we discuss CMR applications in nonischemic cardiomyopathy, ischemic heart disease, arrhythmias, right ventricular diseases, and valvular heart disease. We emphasize the quantitative nature of CMR in current practice, from volumes, function, myocardial strain analysis, and late gadolinium enhancement to parametric mapping, including T1, T2, and T2* relaxation times and extracellular volume fraction assessment.

Improvement of electromagnetic properties at room temperature in La0.625Ca0.375-Sr MnO3:Ag0.2 (x = 0.09–0.15) ceramics by Sr doping

Abstract In this study, facile sol-gel method was used to prepare La0.625Ca0.375-xSrxMnO3:Ag0.2 (LCSMO:Ag0.2, x = 0.09–0.15) polycrystalline ceramics. X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) indicated an increase in grain size of LCSMO:Ag0.2 ceramics with orthorhombic structure as a function of x. Four-probe resistivity temperature system was employed to characterize electrical and magnetic properties of all prepared specimens. Temperature coefficient of resistivity (TCR) and magnetoresistance (MR) yielded room temperature maxima of 4.9% K−1 at 299.2 K and 17.5% at 299.1 K. The enhancement in TCR and MR was mainly attributed to Jahn-Teller (JT) distortion and double exchange (DE) effect. X-ray photoemission spectroscopy (XPS) and inductively coupled plasma-optical emission spectrometer (ICP-OES) all confirmed the existence of silver in metallic forms and the increase of Sr content. On the other hand, satellite peaks in low-temperature range of resistivity-temperature (ρ-T) curves gradually weakened as Sr-doped amount increased. The fitting of ρ-T curves in low-temperature region revealed that gradual vanishing of satellite peak may be due to presence of Sr, able of inhibiting various types of interactions: electron-electron, electron-phonon, and Kondo-like spin-dependent scattering. Overall, room temperature TCR and MR were both optimized by Sr doping, providing further understanding of CMR mechanism and application of manganite materials in electromagnetic equipment under room temperature.

Managing Successional Stage Heterogeneity to Maximize Landscape-Wide Biodiversity of Aquatic Vegetation in Ditch Networks.

The presence of a high diversity of different successional stages in a landscape may help to conserve and promote landscape-wide biodiversity. A strategy to achieve this is using Cyclic Rejuvenation through Management (CRM), an approach employed in a variety of different ecosystems. CRM periodically resets the successional stages in a landscape. For aquatic systems this constitutes vegetation removal and dredging. For this approach to be useful (a) successional stages are required to be different in community composition and (b) these differences need to be caused by true replacement of species between stages. While potentially valid, these assumptions are not generally tested prior to application of CMR. In this study we test these assumptions to explore the usefulness of managing on successional stage heterogeneity for maximizing landscape-wide aquatic plant diversity. We carried out vegetation surveys in the ditch networks of 21 polder landscapes in Netherlands, each containing 24 ditch reaches. Using a clustering approach combined with insight from literature on vegetation succession in these systems we assigned our sampled communities to defined successional stages. After partitioning landscape diversity into its alpha and beta components, we quantified the relative importance of replacement among successional stages. Next, through scenario analyses based on simulations we studied the effects of reducing successional stage heterogeneity on landscape-wide biodiversity. Results showed that differences in community composition among successional stages were a potentially important factor contributing to landscape diversity. Early successional stages were characterized by higher replacement of species compared to late successional stages. In a scenario of gradual decrease of heterogeneity through the systematic loss of the earliest successional stages we found 20% of the species richness in a polder was lost, pointing toward the importance of maintaining early successional stages in a polder. This makes a compelling case for application of CRM within agricultural drainage ditch landscapes to maximize regional aquatic plant diversity. While applied to drainage ditch systems, our data-driven approach is broadly applicable to other systems and may help in providing first indications of the potential of the CRM approach. We argue that CRM may maintain and promote regional biodiversity without compromising the hydrological function of the systems.

Postmortem cardiac magnetic resonance in sudden cardiac death.

Postmortem imaging is increasingly used in forensic practice as good complementary tool to conventional autopsy investigations. Over the last decade, postmortem cardiac magnetic resonance (PMCMR) imaging was introduced in forensic investigations of natural deaths related to cardiovascular diseases, which represent the most common causes of death in developed countries. Postmortem CMR application has yielded interesting results in ischemic myocardium injury investigations and in visualizing other pathological findings in the heart. This review presents the actual state of postmortem imaging for cardiovascular pathologies in cases of sudden cardiac death (SCD), taking into consideration both the advantages and limitations of PMCMR application.

Clinical applications of intra-cardiac four-dimensional flow cardiovascular magnetic resonance: A systematic review

BackgroundFour-dimensional flow cardiovascular magnetic resonance (4D flow CMR) is an emerging non-invasive imaging technology used to visualise and quantify intra-cardiac blood flow. The aim of this systematic review is to assess the literature on the current clinical applications of intra-cardiac 4D flow CMR. MethodsA systematic review was conducted to evaluate the literature on the intra-cardiac clinical applications of 4D flow CMR. Structured searches were carried out on Medline, EMBASE and the Cochrane Library in October 2016. A modified Critical Skills Appraisal Programme (CASP) tool was used to objectively assess and score the included studies. Studies were categorised as ‘highly clinically applicable’ for scores of 67–100%, ‘potentially clinically applicable’ for 34–66% and ‘less clinically applicable’ for 0–33%. ResultsOf the 1608 articles screened, 44 studies met eligibility for systematic review. The included literature consisted of 22 (50%) mechanistic studies, 18 (40.9%) pilot studies and 4 (9.1%) diagnostic studies. Based on the modified CASP tool, 27 (62%) studies were ‘highly clinically applicable’, 9 (20%) were ‘potentially clinically applicable’ and 8 (18%) were ‘less clinically applicable’. ConclusionsThere are many proposed methods for using 4D flow CMR to quantify intra-cardiac flow. The evidence base is mainly mechanistic, featuring single-centred designs. Larger, multi-centre studies are required to validate the proposed techniques and investigate the clinical advantages that 4D flow CMR offers over standard practices.PROSPERO=CRD42016051438.

Applications of cardiac magnetic resonance imaging in sickle cell disease

Cardiac magnetic resonance imaging (CMR) has evolved from an effective research tool to a non-invasive clinical modality with versatile applications. The accuracy of volume measurements and functional assessment and the ability to identify unique myocardial tissue characteristics non-invasively are the primary advantages of CMR. The use of CMR in sickle cell disease (SCD) has been limited clinically to myocardial iron assessment. The use of other CMR applications to characterize the cardiac pathology in SCD is slowly emerging but remains limited to research level. In this review, we discuss some of the applications of CMR in studying cardiovascular diseases and its potential uses in SCD for research and clinical purposes.

016 Uspio-enhanced CMR comprehensive methodological investigation and application in acute MI

Introduction Quantification of active myocardial inflammation may improve diagnosis, guide management and provide trial end-points for novel therapies. Ultrasmall particles of iron oxide (USPIO) are phagocytosed by activated leukocytes and USPIO-enhanced CMR is increasingly used to assess tissue inflammation. We aimed to; 1. Compare T2* imaging with T1 mapping, which is proposed as an alternative for ‘native’ cardiac iron measurement; 2. Determine whether imaging at a single time point post-USPIO is sufficient to detect active accumulation in tissue; 3. Determine whether USPIO signal from infarct and remote zones in acute myocardial infarction (MI) reflects active myocardial accumulation or passive ‘wash-through’ in oedematous myocardium. Methods Four healthy volunteers and six patients with acute MI underwent 1.5T CMR, including T1 and T2* mapping, before and at multiple time points following 4 mg/kg ferumoxytol. Results Normalised T2* of spleen, an organ with high active leukocyte activity, dropped post-USPIO and remained low over the study period (Figure 1), with no correlation seen between spleen T2* and blood T1 (rho=−0.43, p=0.875). In comparison, T1 recovery in spleen correlated strongly with T1 recovery in blood (rho=0.924, p In MI, absolute T2* values dropped and remained significantly lower in infarcted (15 vs 27ms, p Conclusions 0T2* is sensitive to active tissue accumulation of USPIO, likely because T2* reflects field gradients, such as those generated by compartmentalised (phagocytosed) USPIO. T1, which is due to short range dipolar interactions that reduce as USPIOs wash-out, simply tracks passive wash-through. T1 is therefore less suitable for detecting active leukocytes. Measuring T2* at a single time point post-USPIO is insufficient to determine tissue accumulation from passive wash-through. USPIO signal from infarct and remote zones in acute MI appears to genuinely reflect active myocardial accumulation, presumably due to phagocytosis by activated leukocytes.

National judges as gatekeepers to the CMR Convention

One of the great realizations of CMR lies in the fact that it provides uniform rules for contracts for carriage of goods by road. This doesn't mean however that the Convention unified the entire field of road transport logistics, as the scope of application of CMR is restricted by 10 conditions. Despite the great importance of the demarcation of the scope of application, the Convention doesn't provide any guidance as to the interpretation of these conditions. Albeit VCLT requires a treaty autonomous interpretation of the Convention, with this, the Convention gives a wide discretionary margin to individual judges. As a result, judges tend to take into account national law rules to decide upon the applicability and even turn to desirability arguments. With ongoing evolutions in logistics this discretionary margin can even further increase. Literature on VCLT permits an evolutionary evolution of Conventions, in so far the Convention itself implicitly or explicitly permits such interpretation. VCLT itself doesn't give any guidelines of such evolutionary interpretation. With this, individual judges first need to decide whether the Convention was intended to allow for an evolutionary interpretation and later they need to decide what such interpretation would mean for the applicability of the Convention. Unless a new mechanism to safeguard the uniform interpretation of article 1 can be developed, the uniformity brought by CMR is thus at risk to disappear in the future due to the absence of a uniform determination of the scope of application in national case law.

Imaging of patients with implanted devices and arrhythmia

Expanding implantable cardioverter-defibrillator (ICD) indications and significant morbidity and mortality reduction benefits have resulted in a large number of routine ICD implants with appropriate ICD shocks for ventricular arrhythmias. The side-effects and lack of long-term efficacy of antiarrhythmics have made ventricular tachycardia (VT) ablation an increasingly attractive treatment option. Although cardiac magnetic resonance imaging (CMR) is considered the gold standard technique for imaging of myocardial fibrosis to diagnose and guide VT ablation targets in patients with cardiac arrhythmia, safety concerns and significant artifacts from the devices significantly limit the application of CMR. We discuss how to decrease artifact from cardiac devices and the role of a modified inversion pulse late gadolinium enhancement (LGE) CMR sequence as a useful tool in this setting, and we review techniques, safety protocols and limitations from the perspective of our institution’s experience.

2 Clinical application of cardiovascular magnetic resonance in patients with MR-conditional devices: safety, feasibility and clinical impact

Background Implanted cardiac devices were previously considered unsuitable for CMR. With the development of MR-conditional devices, access to CMR has increased, despite concerns regarding image quality and diagnostic accuracy. We aimed to assess the clinical application of CMR in patients wearing MR-conditional devices. Materials and methods We retrospectively enrolled patients wearing MR-conditional devices undergoing a comprehensive CMR protocol (cine, early and late gadolinium enhancement, LGE) in a 1.5T scanner (June 2012–November 2015). Every sequence was analysed by two independent observers and scored according to the effect of artefacts on image quality and interpretation (no, minor and major artefacts). Inter-observer agreement was assessed per sequence and as overall judgement on scan quality and interpretation. Clinical impact of CMR was defined as a change in diagnosis and in management. All devices were interrogated before and after CMR. View this table: Abstract 2 Table 1 Cohen’s kappa for inter-observer agreement on image quality and interpretation per sequence and as overall judgement Results We enrolled 46 consecutive patients (28 male, mean age 56 ± 16 years) wearing MR-conditional pacemaker (22, 48%) and implantable loop recorder (24, 52%). All CMR scans were successfully completed and diagnostic: minor artefacts were recorded in 17 scans (37%), major artefacts in 7 (15%), and no artefacts in 22 (48%). Additional FLASH sequences were performed in 9 patients (20%) to overcome artefacts. Inter-observer agreement on image quality and interpretation was moderate, both overall (kappa 0.454, p < 0.0001) and per sequence, with the exception of long-axis LGE sequences, for which it was fair (kappa 0.284, p = 0.005) ([Table 1][1]). Cine sequences were most affected by artefacts, mainly in the mid-apical left ventricular anterior wall and anteroseptum ([Figure 1][2]). No change in device parameters was reported after the scan. CMR had a clinical impact in 26 patients (57%), determining a change in diagnosis in 16 (35%), in management in 5 (11%) and a change in both in 5 patients (11%). Conclusion With dedicated protocols and under strict monitoring of cardiac devices, CMR is safe and feasible in patients wearing MR-conditional devices, and it also has major clinical impact. ![Abstract 2 Figure 1][3] Abstract 2 Figure 1 Left ventricular segmental analysis to assess artefacts interference. Sixteen-segment model showing that artefacts mostly affect the mid-apical left ventricular anterior and anteroseptal walls, on cine and post-contrast sequences, respectively [1]: #T1 [2]: #F1 [3]: pending:yes

THE POSSIBILITIES OF INSTALLING ELECTRONIC CMR WAYBILL IN ROAD TRANSPORT SECTOR / ELEKTRONINIO CMR VAŽTARAŠČIO DIEGIMO GALIMYBĖS KELIŲ TRANSPORTO SEKTORIUJE

In the article opportunities of changing paper CMR waybill into electronic are analysed, whereas the paper CMR waybill does not guarantee operational information exchange between participants of logistics chain components in road transport. Due to this reason use ofelectronic CMR waybill becomes more and more important. According to researches done by article authors, the article submitted the limitations of paper CMR waybill, benefits of electronic CMR waybill, concept model of implementing electronic CMR waybill and application possibilities of supply chain components. Straipsnyje nagrinėjamos popierinio CMR važtaraščio galimybės keisti jį į elektroninį CMR važtaraštį, nes popierinis jau nebeužtikrina operatyvių informacijos mainų tarp vežimo dalyvių kelių transporte. Naudoti elektroninį važtaraštį tampa vis aktualiau. Remiantis atliktų tyrimų rezultatais straipsnyje pateikiami pagrindiniai popierinio CMR važtaraščio trūkumai, įvardijami elektroninio važtaraščio privalumai, elektroninio CMR važtaraščio realizavimo koncepcinis modelis ir jo taikymo galimybės visiems vežimo dalyviams.