Cardiac magnetic source imaging based on current multipole model

It is widely accepted that the heart current source can be reduced into a current multipole. By adopting three linear inverse methods, the cardiac magnetic imaging is achieved in this article based on the current multipole model expanded to the first order terms. This magnetic imaging is realized in a reconstruction plane in the centre of human heart, where the current dipole array is employed to represent realistic cardiac current distribution. The current multipole as testing source generates magnetic fields in the measuring plane, serving as inputs of cardiac magnetic inverse problem. In the heart-torso model constructed by boundary element method, the current multipole magnetic field distribution is compared with that in the homogeneous infinite space, and also with the single current dipole magnetic field distribution. Then the minimum-norm least-squares （MNLS） method, the optimal weighted pseudoinverse method （OWPIM）, and the optimal constrained linear inverse method （OCLIM） are selected as the algorithms for inverse computation based on current multipole model innovatively, and the imaging effects of these three inverse methods are compared. Besides, two reconstructing parameters, residual and mean residual, are also discussed, and their trends under MNLS, OWPIM and OCLIM each as a function of SNR are obtained and compared.

Investigation of cardiomyopathy using cardiac magnetic resonance imaging part 1:Common phenotypes

Cardiac magnetic resonance imaging(CMRI) has emerged as a useful tertiary imaging tool in the investigation of patients suspected of many different types of cardiomyopathies,CMRI sequences are now of a sufficiently robust quality to enable high spatial and temporal resolution image acquisition.This has led to CMRI becoming an effective non-invasive imaging gold standard for many cardiomyopathies.In this 2-part review,we outline the typical sequences used to image cardiomyopathy,and present the imaging spectrum of cardiomyopathy.Part 1 focuses on the current classification of cardiomyopathy,basic CMRI sequences used in evaluating cardiomyopathy and the imaging spectrum of common phenotypes.

Optimized cardiac magnetic resonance imaging inversion recovery sequence for metal artifact reduction and accurate myocardial scar assessment in patients with cardiac implantable electronic devices

Late gadolinium enhancement(LGE) cardiovascular magnetic resonance(CMR) is the gold standard for imaging myocardial viability.An important application of LGE CMR is the assessment of the location and extent of the myocardial scar in patients with ventricular tachycardia(VT), which allows for more accurate identification of the ablation targets.However, a large percentage of patients with VT have cardiac implantable electronic devices(CIEDs), which is a relative contraindication for cardiac magnetic resonance imaging due to safety and image artifact concerns.Previous studies showed that these patients can be safely scanned on 1.5 T scanners provided that an adequate imaging protocol is adopted.Nevertheless, imaging patients with a CIED result in metal artifacts due to the strong frequency off-resonance effects near the device; therefore, the spins in the surrounding myocardium are not completely inverted, and thus give rise to hyperintensity artifacts.These artifacts obscure the myocardial scar tissue and limit the ability to study the correlation between the myocardial scar structure and the electro-anatomical map during catheter ablation.In this study, we developed a modified inversion recovery technique to alleviate the CIED-induced metal artifacts and improve the diagnostic image quality of LGE images in patients with CIEDs without increasing scan time or requiring additional hardware.The developed technique was tested in phantom experiments and in vivo scans, which showed its capability for suppressing the hyperintensity artifacts without compromising myocardium nulling in the resulting LGE images.

Cardiac functional magnetic resonance imaging at 7T:Image quality optimization and ultra-high field capabilities

BACKGROUND 7T cardiac magnetic resonance imaging(MRI)introduces several advantages,as well as some limitations,compared to lower-field imaging.The capabilities of ultra-high field(UHF)MRI have not been fully exploited in cardiac functional imaging.AIM To optimize 7T cardiac MRI functional imaging without the need for conducting B1 shimming or subject-specific tuning,which improves scan efficiency.In this study,we provide results from phantom and in vivo scans using a multi-channel transceiver modular coil.METHODS We investigated the effects of adding a dielectric pad at different locations next to the imaged region of interest on improving image quality in subjects with different body habitus.We also investigated the effects of adjusting the imaging flip angle in cine and tagging sequences on improving image quality,B1 field homogeneity,signal-to-noise ratio(SNR),blood-myocardium contrast-to-noise ratio(CNR),and tagging persistence throughout the cardiac cycle.RESULTS The results showed the capability of achieving improved image quality with high spatial resolution(0.75 mm×0.75 mm×2 mm),high temporal resolution(20 ms),and increased tagging persistence(for up to 1200 ms cardiac cycle duration)at 7T cardiac MRI after adjusting scan set-up and imaging parameters.Adjusting the imaging flip angle was essential for achieving optimal SNR and myocardium-toblood CNR.Placing a dielectric pad at the anterior left position of the chest resulted in improved B1 homogeneity compared to other positions,especially in subjects with small chest size.CONCLUSION Improved regional and global cardiac functional imaging can be achieved at 7T MRI through simple scan set-up adjustment and imaging parameter optimization,which would allow for more streamlined and efficient UHF cardiac MRI.

The Role of Clinical Cardiac Magnetic Resonance Imaging in China:Current Status and the Future

Cardiac magnetic resonance(CMR)imaging plays an important role in the diagnosis and management of cardiovascular diseases.The state-of-the-art CMR imaging has many advantages in cardiac imaging,including excellent spatial and temporal resolution,unrestricted imaging fi eld,no exposure to ionizing radiation,excellent tissue contrast,and unique myocardial tissue characterization.Clinical CMR imaging is used during the cardiovascular diagnostic workup in the United States and some European countries.Use of CMR imaging is emerging in hospitals in China and has a promising future.This review briefl y describes the real-world clinical application of CMR imaging in China and discuss obstacles for its future development.

Role of cardiac magnetic resonance imaging in the diagnosis and management of COVID-19 related myocarditis: Clinical and imaging considerations

There is a growing evidence of cardiovascular complications in coronavirusdisease 2019 (COVID-19) patients. As evidence accumulated of COVID-19 mediatedinflammatory effects on the myocardium, substantial attention has beendirected towards cardiovascular imaging modalities that facilitate this diagnosis.Cardiac magnetic resonance imaging (CMRI) is the gold standard for thedetection of structural and functional myocardial alterations and its role inidentifying patients with COVID-19 mediated cardiac injury is growing. Despiteits utility in the diagnosis of myocardial injury in this population, CMRI’s impacton patient management is still evolving. This review provides a framework for theuse of CMRI in diagnosis and management of COVID-19 patients from theperspective of a cardiologist. We review the role of CMRI in the management ofboth the acutely and remotely COVID-19 infected patient. We discuss patientselection for this imaging modality;T1, T2, and late gadolinium enhancementimaging techniques;and previously described CMRI findings in other cardiomyopathieswith potential implications in COVID-19 recovered patients.

Cardiac Amyloidosis: The Role of Magnetic Resonance Imaging

Amyloidosis, an infiltrative disease characterized by deposition of high molecular weight insoluble protein has a low detection rate and poor prognosis with congestive heart failure being the most common cause of death. Although definitive diagnosis is based on endomyocardial biopsy, this is rarely performed due to procedural risk and sampling error. Traditional non-invasive imaging, such as transthoracic echocardiography (TTE) and electrocardiogram (ECG) lacks sensitivity detecting the disease in its early stages. This case report demonstrates the utility of cardiac Magnetic Resonance Imaging in addition to traditional imaging modalities in this often clinically challenging problem.

Effects of Weight Loss on Pericardial Fat and Left Ventricular Mass Assessed with Cardiac Magnetic Resonance Imaging in Morbid Obesity

Background: Obesity is a risk factor for cardiovascular disease and mortality. Significant weight loss has beneficial effects on left ventricular structure, in particular on regression of left ventricular hypertrophy (LVH). We therefore evaluated the consequences of significant weight loss on left ventricular morphology, hemodynamics and pericardial fat. Methods: We performed volumetric cardiac magnetic resonance (CMR) imaging before and after significant weight loss due to laparoscopic adjustable gastric banding (LAGB). CMR was used to measure cardiac mass, volume and function, as well as to quantify pericardial fat. Results: Eleven patients (age 40.5 ± 10 yrs, body mass index 42.5 ± 3.9 kg/m2) underwent CMR imaging before and a median 15.4 months after gastric banding. The BMI declined by 9.3 ± 3.3 kg/m2 (p Discussion: Significant weight loss in obesity is accompanied by a marked regression of LVH, with no apparent change in cardiac volume or function. The local effect of a diminished amount of pericardiac fat tissue may be more important than absolute weight loss with respect to the regression of LVH in obesity.

Correlation between myocardial infarction activity assessed by cardiac magnetic resonance imaging and the evolution of cardiac function after PCI

Objective:To investigate the correlation of cardiac magnetic resonance imaging(MRI)in the assessment of myocardial activity in patients with myocardial infarction and the outcome of cardiac function after PCI.Methods:30 patients with myocardial infarction(MI)who had complete clinical and imaging data from July 2016 to December 2018 after PCI were analyzed retrospectively.MR and echocardiogram were performed before and 6 months after PCI,and the parameters related to left ventricular function were measured by post-processing software of MRI workstation.The left ventricular transmural degree of CMR late gadolinium enhancement was compared with the left ventricular wall motion degree of 6-month echocardiography as a standard to judge the viable myocardium.Result:There were 193 left ventricular segmental abnormalities in 30 cases,including 121 viable myocardium and 72 non viable myocardium in CMR-LGE before operation.Six months after PCI,echocardiography showed that 125 of 193 abnormal segments of left ventricle detected by CMR-LGE before PCI were viable myocardium and 68 were non viable myocaridium.The sensitivity and specificity of CMR-LGE to determinate of viable myocardium were 92.0%and 91.1%respectively.The larger the non-viable myocardial area of the left ventricular wall,the worse the recovery of wall motion ability,and there was a negative correlation between them(r=0.416,P<0.05).The first-pass perfusion time in CMR-LEG region was significantly longer than that in normal myocardial region(4.85(+)1.51)s and(3.79(+)1.73)s,respectively.The difference was statistically significant(t=5.191,P<0.05).Conclusion:MRI can evaluate the myocardial activity of myocardial infarction,reflect the range of viable myocardium,and provide imaging basis for clinical treatment and prognosis.

Cardiac involvement in hydrocarbon inhalant toxicity--role of cardiac magnetic resonance imaging:A case report

BACKGROUND We report a patient who was diagnosed with toxic myopericarditis secondary to hydrocarbon abuse using cardiac magnetic resonance imaging(CMR).CASE SUMMARY A 25-year-old male presented to emergency department with chest pain for 3 d.Patient also reported sniffing hydrocarbon containing inhalant for the last 1 year.Labs showed elevated troponin and electrocardiography was suggestive of acute pericarditis.Echocardiogram showed left ventricular(LV)ejection fraction(EF)of 40%.Given patient’s troponin elevation and reduced EF,cardiac catheterization was performed which showed normal coronaries.CMR was performed for myocardial infarction with non-obstructive coronary arteries evaluation.CMR showed borderline LV function with edema in mid and apical LV suggestive of myocarditis.CONCLUSION CMR can be used to diagnose toxic myopericarditis secondary to hydrocarbon abuse.

Role of cardiac magnetic resonance imaging in troponinemia syndromes

Cardiac magnetic resonance imaging(MRI)is an evolving technology,proving to be a highly accurate tool for quantitative assessment.Most recently,it has been increasingly used in the diagnostic and prognostic evaluation of conditions involving an elevation in troponin or troponinemia.Although an elevation in troponin is a nonspecific marker of myocardial tissue damage,it is a frequently ordered investigation leaving many patients without a specific diagnosis.Fortunately,the advent of newer cardiac MRI protocols can provide additional information.In this review,we discuss several conditions associated with an elevation in troponin such as myocardial infarction,myocarditis,Takotsubo cardiomyopathy,coronavirus disease 2019 related cardiac dysfunction and athlete’s heart syndrome.

Impact of cardiac magnet resonance imaging on management of ventricular septal rupture after acute myocardial infarction

A 74-year-old man was admitted to the cardiac catheterization laboratory with acute myocardial infarction. After successful angioplasty and stent implantation into the right coronary artery, he developed cardiogenic shock the following day. Echocardiography showed ventricular septal rupture. Cardiac magnet resonance imaging (MRI) was performed on the critically ill patient and provided detailed information on size and localization of the ruptured septum by the use of fast MRI sequences. Moreover, the MRI revealed that the ventricular septal rupture was within the myocardial infarction area, which was substantially larger than the rupture. As the patient's condition worsened, he was intubated and had intra-aortic balloon pump implanted, and extracorporeal membrane oxygenation was initiated. During the following days, the patient's situation improved, and surgical correction of the ventricular septal defect could successfully be performed. To the best of our knowledge, this case report is the first description of postinfarction ventricular septal rupture by the use of cardiac MRI in an intensive care patient with cardiogenic shock and subsequent successful surgical repair.

Clinical decision support systems for brain tumor characterization using advanced magnetic resonance imaging techniques

In recent years, advanced magnetic resonance imaging(MRI) techniques, such as magnetic resonance spec-troscopy, diffusion weighted imaging, diffusion tensor imaging and perfusion weighted imaging have been used in order to resolve demanding diagnostic prob-lems such as brain tumor characterization and grading, as these techniques offer a more detailed and non-invasive evaluation of the area under study. In the last decade a great effort has been made to import and utilize intelligent systems in the so-called clinical deci-sion support systems(CDSS) for automatic processing, classification, evaluation and representation of MRI data in order for advanced MRI techniques to become a part of the clinical routine, since the amount of data from the aforementioned techniques has gradually inticle is two-fold. The first is to review and evaluate the progress that has been made towards the utilization of CDSS based on data from advanced MRI techniques. The second is to analyze and propose the future work that has to be done, based on the existing problems and challenges, especially taking into account the new imaging techniques and parameters that can be intro-duced into intelligent systems to significantly improve their diagnostic specificity and clinical application.

Long term evolution of magnetic resonance imaging characteristics in a case of atypical left lateral wall hypertrophic cardiomyopathy

We are reporting a long-time magnetic resonance imaging(MRI) follow-up in a rare case of cardiac left lateral wall hypertrophy. Hypertrophic cardiomyopathy(HCM) is the most common genetic cardiovascular disorder and a significant cause of sudden cardiac death. Cardiac magnetic resonance(CMR) imaging can be a valuable tool for assessment of detailed information on size,localization,and tissue characteristics of hypertrophied myocardium. However,there is still little knowledge of long-term evolution of HCM as visualized by magnetic resonance imaging. Recently,our group reported a case of left lateral wall HCM as a rare variant of the more common forms,such as septal HCM,or apical HCM. As we now retrieved an old cardiac MRI acquired in this patient more than 20 years ago,we are able to provide the thrilling experience of an ultra-long MRI followup presentation in this rare case of left lateral wall hypertrophy. Furthermore,this case outlines the tremendous improvements in imaging quality within the last two decades of CMR imaging.

A Rare Case of Concordant Atrioventricular Connection to L-Looped Ventricles in Situs Solitus:4-Dimensional Magnetic Resonance Imaging and 3D Printing

An infant male presented with the rare anatomy consisting of situs solitus,concordant atrioventricular connections to L-looped ventricles,double outlet right ventricle(DORV),and hypoplastic aortic arch.6 months after neonatal aortic arch repair,the morphologic right ventricle function deteriorated,and surgical evaluation was undertaken to determine if either biventricular repair with a systemic morphologic left ventricle or right ventricular exclusion was possible.After initial echocardiography,magnetic resonance imaging(MRI)was used to create detailed axial and 4-dimensional(4D)images and 3-dimensional(3D)printed models.The detailed anatomy of this rare,complex case and its use in pre-surgical planning is presented.

Forward and inverse problem for cardiac magnetic field and electric potential using two boundary element methods

This paper discusses the forward and inverse problem for cardiac magnetic fields and electric potentials. A torso-heart model established by boundary element method （BEM） is used for studying the distributions of cardiac magnetic fields and electric potentials. Because node-to-node and triangle-to-triangle BEM can lead to discrepant field distributions, their properties and influences are compared. Then based on constructed torso-heart model and supposed current source functional model-current dipole array, the magnetic and electric imaging by optimal constrained linear inverse method are applied at the same time. Through figure and reconstructing parameter comparison, though the magnetic current dipole array imaging possesses better reconstructing effect, however node-to-node BEM and triangleto-triangle BEM make little difference to magnetic and electric imaging.

Cardiac involvement in disseminated diffuse large B-cell lymphoma,successful management with chemotherapy dose reduction guided by cardiac imaging: A case report and review of literature

BACKGROUND Secondary cardiac involvement by lymphoma has received limited attention in the medical literature, despite its grave prognosis. Although chemotherapy improves patients' survival, a subgroup of treated patients dies suddenly due to myocardial rupture following chemotherapy initiation. Reducing the initial chemotherapy dose with dose escalation to standard doses may be effective in minimizing this risk but the data are limited. We report on the successful management of a patient with disseminated diffuse large B-cell lymphoma(DLBCL) involving the heart using such approach.CASE SUMMARY An 18-year-old male presented to our hospital with six months history of progressive dyspnea, orthopnea and cough. On physical examination, the patient was found to have a plethoric and mildly edematous face, fixed elevation of the right internal jugular vein, suggestive of superior vena cava obstruction, and a pelvic mass. Investigations during admission including a thoracoabdominal computed tomography(CT) scan with CT guided biopsy of the pelvic mass,echocardiography and cardiac magnetic resonance imaging led to the diagnosis of disseminated DLBCL with cardiac involvement. The patients were successfully treated with chemotherapy dose reduction followed by dose escalation to standard doses, under the guidance of cardiac imaging. The patient completed chemotherapy and underwent a successful bone marrow transplant. He is currently in remission and has a normal left ventricular function.CONCLUSION Imaging-guided chemotherapy dosing may minimize the risk of myocardial rupture in cardiac lymphoma. Data are limited. Management should be individualized.

Multi-modality imaging of cardiac amyloidosis: Contemporary update

Cardiac amyloidosis is a heterogeneous and challenging diagnostic disease with poor prognosis that is now being altered by introduction of new therapies.Echocardiography remains the first-line imaging tool, and when disease is suspected on echocardiography, cardiac magnetic resonance imaging and nuclear imaging play critical roles in the non-invasive diagnosis and evaluation of cardiac amyloidosis. Advances in multi-modality cardiac imaging allowing earlier diagnosis and initiation of novel therapies have significantly improved the outcomes in these patients. Cardiac imaging also plays important roles in the risk stratification of patients presenting with cardiac amyloidosis. In the current review, we provide a clinical and imaging focused update, and importantly outline the imaging protocols, diagnostic and prognostic utility of multimodality cardiac imaging in the assessment of cardiac amyloidosis.

Fabry Disease: Update, Focusing on Heart Disease by Multimodal Imaging

Fabry disease (FD) is a rare X-linked lysosomal accumulation disorder caused by a deficiency in the enzyme alpha-galactosidase A (Gal A), resulting in excessive storage of glycosphingolipids, particularly globotriaosylceramide (Gb3). This leads to cellular dysfunction in various organs, with cardiovascular compromise being the major cause of morbidity and mortality. This study aimed to provide a comprehensive overview of FD focusing on its genetic, epidemiological, clinical, diagnostic, and therapeutic aspects. This study explored the genetic mutations associated with FD, its epidemiology, clinical phenotypes, cardiac manifestations, diagnostic approaches, and current treatment options. Background: FD is caused by mutations in GLA on the X chromosome, with over 1000 identified variants. Neonatal screening and specific studies have shown an increased incidence of FD. The clinical presentation varies between classic and late phenotypes, with cardiac involvement being a major concern, particularly in late-onset FD. Purpose: This study aimed to summarize the current knowledge on FD, emphasizing cardiac involvement, diagnostic modalities, and treatment options. Methods: A literature review of relevant studies on FD, including genetics, epidemiology, clinical presentation, diagnostic methods, and treatment options, was conducted. Results: Cardiac manifestations of FD included left ventricular hypertrophy (LVH), heart failure, arrhythmias, and sudden death. Diagnostic approaches such as electrocardiography, echocardiography, and cardiac magnetic resonance imaging play crucial roles in the early detection and monitoring of cardiac involvement. Enzyme replacement therapy (ERT) and emerging treatments have shown promise in managing FD, although challenges remain. Conclusions: FD remains a challenging condition in cardiology, with under-diagnosis being a concern. Early detection and specific therapy are essential to improve patient outcomes. Echocardiography and cardiac MRI are valuable tools for diagnosis and follow-up. Despite the advances in treatment, accessibility remains an issue. More research is needed to deepen our understanding of FD and to improve therapeutic strategies.

Diagnostic and prognostic value of cardiac imaging in amyloidosis

Amyloidosis is an infiltrative disease caused by extracellular protein deposition that has accumulated a lot of scientific production in recent years.Different types of amyloidosis can affect the heart.Transthyretin amyloidosis and light chain amyloidosis are the two most common types of cardiac amyloidosis.These entities have a poor prognosis,so accurate diagnostic techniques are imperative for determining an early therapeutic approach.Recent advances in cardiac imaging and diagnostic strategies show that these tools are safe and can avoid the use of invasive diagnostic techniques to histological confirmation,such as endomyocardial biopsy.We performed a review on the diagnostic and prognostic implications of different cardiac imaging techniques in cardiac amyloidosis.We mainly focus on reviewing echocardiography,cardiac magnetic resonance,computed tomography and nuclear imaging techniques and the different safety measurements that can be done with each of them.