Nuclear Cardiac Imaging Research Articles

Tracking the pre-clinical progression of transthyretin amyloid cardiomyopathy using artificial intelligence-enabled electrocardiography and echocardiography.

Diagnosing transthyretin amyloid cardiomyopathy (ATTR-CM) requires advanced imaging, precluding large-scale testing for pre-clinical disease. We examined the application of artificial intelligence (AI) to echocardiography (TTE) and electrocardiography (ECG) as a scalable strategy to quantify pre-clinical trends in ATTR-CM. Across age/sex-matched case-control datasets in the Yale-New Haven Health System (YNHHS) we trained deep learning models to identify ATTR-CM-specific signatures on TTE videos and ECG images (area under the curve of 0.93 and 0.91, respectively). We deployed these across all studies of individuals referred for cardiac nuclear amyloid imaging in an independent population at YNHHS and an external population from the Houston Methodist Hospitals (HMH) to define longitudinal trends in AI-defined probabilities for ATTR-CM using age/sex-adjusted linear mixed models, and describe discrimination metrics during the early pre-clinical stage. Among 984 participants referred for cardiac nuclear amyloid imaging at YNHHS (median age 74 years, 44.3% female) and 806 at HMH (69 years, 34.5% female), 112 (11.4%) and 174 (21.6%) tested positive for ATTR-CM, respectively. Across both cohorts and modalities, AI-defined ATTR-CM probabilities derived from 7,423 TTEs and 32,205 ECGs showed significantly faster progression rates in the years before clinical diagnosis in cases versus controls (p time × group interaction ≤0.004). In the one-to-three-year window before cardiac nuclear amyloid imaging sensitivity/specificity metrics were estimated at 86.2%/44.2% [YNHHS] vs 65.7%/65.5% [HMH] for AI-Echo, and 89.8%/40.6% [YNHHS] vs 88.5%/35.1% [HMH] for AI-ECG. We demonstrate that AI tools for echocardiographic videos and ECG images can enable scalable identification of pre-clinical ATTR-CM, flagging individuals who may benefit from risk-modifying therapies.

A Multiscale Spatial Transformer U-Net for Simultaneously Automatic Reorientation and Segmentation of 3-D Nuclear Cardiac Images

A Multiscale Spatial Transformer U-Net for Simultaneously Automatic Reorientation and Segmentation of 3-D Nuclear Cardiac Images

Cardiovascular Imaging, Climate Change, and Environmental Sustainability.

Environmental exposures including poor air quality and extreme temperatures are exacerbated by climate change and are associated with adverse cardiovascular outcomes. Concomitantly, the delivery of health care generates substantial atmospheric greenhouse gas (GHG) emissions contributing to the climate crisis. Therefore, cardiac imaging teams must be aware not only of the adverse cardiovascular health effects of climate change, but also the downstream environmental ramifications of cardiovascular imaging. The purpose of this review is to highlight the impact of climate change on cardiovascular health, discuss the environmental impact of cardiovascular imaging, and describe opportunities to improve environmental sustainability of cardiac MRI, cardiac CT, echocardiography, cardiac nuclear imaging, and invasive cardiovascular imaging. Overarching strategies to improve environmental sustainability in cardiovascular imaging include prioritizing imaging tests with lower GHG emissions when more than one test is appropriate, reducing low-value imaging, and turning equipment off when not in use. Modality-specific opportunities include focused MRI protocols and low-field-strength applications, iodine contrast media recycling programs in cardiac CT, judicious use of US-enhancing agents in echocardiography, improved radiopharmaceutical procurement and waste management in nuclear cardiology, and use of reusable supplies in interventional suites. Finally, future directions and research are highlighted, including life cycle assessments over the lifespan of cardiac imaging equipment and the impact of artificial intelligence tools. Keywords: Heart, Safety, Sustainability, Cardiovascular Imaging Supplemental material is available for this article. © RSNA, 2024.

Cardiac Nuclear Imaging Findings in Atypical Variants of Takotsubo Cardiomyopathy

Background: In addition to the typical form resembling the classical Japanese octopus trap, atypical variants of Takotsubo cardiomyopathy (TTC) sparing the left ventricular apex have emerged over the years. The aim of this systematic review is to provide a comprehensive overview of the cardiac nuclear imaging findings in atypical variants. Methods: This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The literature research was carried out online on the Pubmed, Scopus, Central (Cochrane Library), and Web Of Science databases. Results: A total of 14 articles were ultimately selected. Myocardial perfusion scintigraphy was performed in nine studies, followed by 123I-mIBG scintigraphy, 123I-BMIPP scintigraphy, and 18F-FDG PET. In seven cases, a single cardiac nuclear imaging technique was performed, while in the remaining five and two cases, two and three different imaging modalities were, respectively, used. The most common atypical variant of our selection was the midventricular form, followed by reverse/inverted/basal TTC, with only a single case reported of a focal pattern. Conclusions: As the reason why TTC variants occur is still not clear, a deeper understanding of the current knowledge could be the basis for providing more insights into this fascinating disorder and its uncommon manifestations.

4Dimensional XStrain Echocardiography: Comprehensive Evaluation of Non-obstructive Hypertrophic Cardiomyopathy- A Case Report and Review of Literature

Hypertrophic cardiomyopathy (HCM) is a relatively common inherited cardiomyopathy, which is occasionally challenging to differentiate from hypertensive heart disease and athletes heart on the basis of morphologic or functional abnormalities alone. Imaging studies provide solution for majority of clinical presentations. Generally, transthoracic echocardiography (TTE) is employed as a first line imaging tool and contrast enhanced echocardiography (CEE), contrast tuned imaging echocardiography (CTIE), cardiac magnetic resonance (CMR), cardiac computed tomography (CCT), cardiac nuclear imaging and speckle tracking echocardiography (STE) are encouraged for either suboptimal studies because of poor visualization of left ventricular (LV) cavity or for comprehensive delineation of the cardiac anatomy, its widespread left and right ventricular involvement, associations and complications. We are reporting a case of 48-year old male presenting to us with atypical chest pain and a history of suspicious solitary episode of syncope. His routine ECG was indicative of left ventricular hypertrophy with strain pattern, and his TTE was substandard and inadequate in the apical four chamber (4CH) and five chamber (5CH) views, hence CTIE was performed without the application of intravenous contrast agents, to produce a remarkable illustration of HCM.
 Keywords: Hypertrophic cardiomyopathy, contrast echocardiography, contrast tuned imaging, speckle tracking echocardiography, 4Dimensional XStrain, Non obstructive HCM

Incidental scan findings in cardiac amyloid scintigraphy

When interpreting amyloid scintigraphy the nuclear cardiology physician should be aware of incidental image findings that may interfere with scan interpretation and may be of potential clinical significance. As for other nuclear cardiac imaging it is important to inspect the entire field of view of the planar and SPECT images. Correlation with the patient’s history and physical examination is crucial in interpretation of these incidental findings.

What Is New in Risk Assessment in Nuclear Cardiology?

Nuclear cardiology techniques allow in-depth evaluation of cardiac patients. A body of literature has established the use of nuclear cardiology. The results obtained with traditional cameras have been reinforced by those obtained with a series of innovations that have revolutionized the field of nuclear cardiology. This article highlights the role of nuclear cardiology in the risk assessment of patients with cardiac disease and sheds light on advancements of nuclear imaging techniques in the cardiovascular field. Patient risk stratification has a key role in modern precision medicine. Nuclear cardiac imaging techniques may quantitatively investigate major disease mechanisms of different cardiac pathologies.

Multimodality Imaging in Arrhythmogenic Left Ventricular Cardiomyopathy

The term arrhythmogenic cardiomyopathy (ACM) describes a large spectrum of myocardial diseases characterized by progressive fibrotic or fibrofatty replacement, which gives the substrate for the occurrence of ventricular tachyarrhythmias and the development of ventricular dysfunction. This condition may exclusively affect the left ventricle, leading to the introduction of the term arrhythmogenic left ventricular cardiomyopathy (ALVC). The clinical features of ALVC are progressive fibrotic replacement with the absence or mild dilation of the LV and the occurrence of ventricular arrhythmias within the left ventricle. In 2019, the diagnostic criteria for the diagnosis of ALVC, based on family history and clinical, electrocardiographic, and imaging features, have been proposed. However, since the significant clinical and imaging overlap with other cardiac diseases, genetic testing with the demonstration of a pathogenic variant in an ACM-related gene is required for diagnostic confirmation. In ALVC, the multimodality imaging approach comprises different imaging techniques, such as echocardiography, cardiac magnetic resonance, and cardiac nuclear imaging. It provides essential information for the diagnosis, differential diagnosis, sudden cardiac death risk stratification, and management purposes. This review aims to elucidate the current role of the different multimodality imaging techniques in patients with ALVC.

The role of cardiac nuclear imaging of women with suspected coronary artery disease: data from Latvian cardiac SPECT registry

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Cardiac imaging is a leading method in the diagnosis and treatment of ischemic heart disease. As the prognostic value of exercise stress tests for women is relatively low, ESC Guidelines suggest more accurate imaging method. Myocardial perfusion imaging with SPECT is one of the most commonly performed non-invasive cardiac imaging tests evaluating myocardial viability, assessing prognosis and estimating the efficacy of therapy. Purpose To determine the role for cardiac nuclear imaging for women with suspected coronary artery disease (CAD) in Latvia and to analyze prescribed further diagnostic approaches to establish the diagnosis and appropriate treatment. Methods For women included in Latvian cardiac SPECT registry the cardiac SPECT was performed in single University Hospital from 2018 till 2021. The patients were divided into 2 groups: normal myocardial perfusion and true myocardial perfusion defect, defined as area of ischemia ≥ 10% of the left ventricle myocardium. Patients with perfusion defect were analyzed according to prescribed further diagnostic test or treatment option. Results 700 women with suspected CAD were analyzed. True myocardial perfusion defect was detected in 120 patients (17.1%). As further diagnostic approach in 29 (24.2%) cases cardiac computed tomography angiography (CTA) was performed; the invasive coronary angiography (ICA) - in 76 (63.3%) cases and percutaneous coronary intervention (PCI) in 15 (12.5%) cases was suggested. Analyzing results of all performed CTAs’, stenosis in main coronary arteries were not found (100%) and CAD was excluded. Of all performed ICA, in 41 (53.9%) women atherosclerosis in main coronary arteries was not observed and microvascular angina as a primary diagnosis was assessed. In 17 (22.3%) patients the significant stenosis in main coronary arteries was present and PCI was performed, of whom 10 (58.5%) women were primarily diagnosed. 1 patient (1.3%) underwent coronary artery bypass surgery (CBP). In 9 (11.8%) patients significant stenosis was not detected and they were discharged on optimal medical treatment (OMT). In all these 9 patients the CAD was already known before the SPECT. From all suggested PCIs’: 8 women underwent PCI (53.3 %), 1 – CBP (6.6%) and 6 (40%) patients continued OMT. Conclusion Based on Latvian cardiac SPECT registry data, myocardial perfusion imaging with cardiac SPECT is valuable and is highly recommended for the diagnostics of women with known or suspected CAD. Despite the low availability of cardiac SPECT in Latvia, the registry shows the importance of nuclear diagnostics for such a difficult to diagnose group as women.

Multimodality Imaging in Cardiomyopathies with Hypertrophic Phenotypes.

Multimodality imaging is a comprehensive strategy to investigate left ventricular hypertrophy (LVH), providing morphologic, functional, and often clinical information to clinicians. Hypertrophic cardiomyopathy (HCM) is defined by an increased LV wall thickness not only explainable by abnormal loading conditions. In the context of HCM, multimodality imaging, by different imaging techniques, such as echocardiography, cardiac magnetic resonance, cardiac computer tomography, and cardiac nuclear imaging, provides essential information for diagnosis, sudden cardiac death stratification, and management. Furthermore, it is essential to uncover the specific cause of HCM, such as Fabry disease and cardiac amyloidosis, which can benefit of specific treatments. This review aims to elucidate the current role of multimodality imaging in adult patients with HCM.

Artificial Intelligence Advances in the World of Cardiovascular Imaging

The tremendous advances in digital information and communication technology have entered everything from our daily lives to the most intricate aspects of medical and surgical care. These advances are seen in electronic and mobile health and allow many new applications to further improve and make the diagnoses of patient diseases and conditions more precise. In the area of digital radiology with respect to diagnostics, the use of advanced imaging tools and techniques is now at the center of evaluation and treatment. Digital acquisition and analysis are central to diagnostic capabilities, especially in the field of cardiovascular imaging. Furthermore, the introduction of artificial intelligence (AI) into the world of digital cardiovascular imaging greatly broadens the capabilities of the field both with respect to advancement as well as with respect to complete and accurate diagnosis of cardiovascular conditions. The application of AI in recognition, diagnostics, protocol automation, and quality control for the analysis of cardiovascular imaging modalities such as echocardiography, nuclear cardiac imaging, cardiovascular computed tomography, cardiovascular magnetic resonance imaging, and other imaging, is a major advance that is improving rapidly and continuously. We document the innovations in the field of cardiovascular imaging that have been brought about by the acceptance and implementation of AI in relation to healthcare professionals and patients in the cardiovascular field.

Nuclear Cardiac Imaging in the Interventional Suite.

This review presents the current state of imaging approaches that enable real-time molecular imaging in the interventional suite and discusses the potential future use of integrated nuclear imaging and fluoroscopy for intraprocedural guidance in the evaluation and treatment of both cardiovascular and oncological diseases. Although there are no commercially available real-time hybrid nuclear imaging devices that are approved for use in the interventional suite, prototype open gantry hybrid nuclear imaging and x-ray c-arm imaging systems and theranostic catheter for location radiotracer detection are currently undergoing development and testing by multiple groups. The integration of physiological and molecular targeted nuclear imaging for real-time delivery of targeted theranostics in the interventional laboratory may enable more personalized care for a wide variety of cardiovascular procedures and improve patient outcomes.

Editorial V1 N1

The birth of a new journal is usually a cause for singular rejoicing and anticipation. On this occasion, however, the moment is steeped in melancholy with the recent passing of Professor Avijit Lahiri, the journal’s founder. He lived life to the full. Avijit touched countless friends and colleagues with his support, kindness and mentorship. At the same time, he was a pioneer in cardiodiabetes, an excellent clinician and an outstanding academic mind. In short, he was a trailblazer. His accomplishments are too numerous to list but ranged from playing the key role in the development of nuclear cardiac imaging as well as being a Founder President of the International Congress of Nuclear Cardiology to the creation of the British Cardiac Research Trust. He introduced cardiac CT to the UK and contributed to practice-changing guideline committees on cardiac imaging in diabetes.

A myocardial extraction method using deep learning for 99mTc myocardial perfusion SPECT images: A basic study to reduce the effects of extra-myocardial activity

AimThe purpose of this study was to automatically extract myocardial regions from transaxial single-photon emission computed tomography (SPECT) images using deep learning to reduce the effects of extracardiac activity, which has been problematic in cardiac nuclear imaging. Method: Myocardial region extraction was performed using two deep neural network architectures, U-Net and U-Net ++, and 694 myocardial SPECT images manually labeled with myocardial regions were used as the training data. In addition, a multi-slice input method was introduced during the learning session while taking the relationships to adjacent slices into account. Accuracy was assessed using Dice coefficients at both the slice and pixel levels, and the most effective number of input slices was determined. Results: The Dice coefficient was 0.918 at the pixel level, and there were no false positives at the slice level using U-Net++ with 9 input slices. Conclusion: The proposed system based on U-Net++ with multi-slice input provided highly accurate myocardial region extraction and reduced the effects of extracardiac activity in myocardial SPECT images.

State-of-the-art modalities in cardio-oncology: insight from a nuclear medicine approach.

Cancer and cardiovascular disease are the most significant causes of morbidity and mortality worldwide. Although the cancer survival rate has increased due to improved treatment approaches, especially targeted therapy, some side effects such as cardiotoxicity decrease the efficiency of the clinical outcome. Radiation therapy and chemotherapy have a long-established history of potential cardiotoxic effects. A new multi-disciplinary and translational field known as cardio-oncology has been developed for the identification, prevention, and treatment of cardiovascular dysfunctions associated with cancer treatment approaches. One of the important tools for detecting and monitoring cardiotoxic effects is non-invasive nuclear cardiac imaging techniques. Cardiac nuclear imaging modalities especially recent findings positron emission tomography (PET) tracers have a quintessential role in the early detection of cardiovascular disorders. Moreover, comprehensive studies are required to investigate novel nuclear medicine treatment approaches such as peptide receptor radionuclide therapy (PRRT), fibroblast activation protein (FAP), and chemokine receptor (CXCR) targeting probes for possible cardiac side effects that play important roles in the treatment of malignancies.

Personalized ischemia diagnostics in chronic coronary syndrome

Myocardial ischemia is triggered by amismatch between the oxygen supply and demand of the myocardial tissue. The most common cause is coronary artery disease; however, not every coronary stenosis is hemodynamically relevant and leads to myocardial ischemia. The guidelines recommend noninvasive ischemia diagnostics prior to invasive treatment in patients with chronic coronary syndrome. Cardiac computed tomography, stress echocardiography, nuclear cardiological procedures (positron emission tomography and single photon emission computed tomography) and cardiac magnetic resonance imaging are the main diagnostic tools for this purpose and are incorporated into the clinical routine. This article provides a review of the indications, the relative advantages and disadvantages of the respective methods and their utilization in routine clinical practice.

Artificial intelligence in personalized cardiovascular medicine and cardiovascular imaging.

The collection of large, heterogeneous electronic datasets and imaging from patients with cardiovascular disease (CVD) has lent itself to the use of sophisticated analysis using artificial intelligence (AI). AI techniques such as machine learning (ML) are able to identify relationships between data points by linking input to output variables using a combination of different functions, such as neural networks. In cardiovascular medicine, this is especially pertinent for classification, diagnosis, risk prediction and treatment guidance. Common cardiovascular data sources from patients include genomic data, cardiovascular imaging, wearable sensors and electronic health records (EHR). Leveraging AI in analysing such data points: (I) for clinicians: more accurate and streamlined image interpretation and diagnosis; (II) for health systems: improved workflow and reductions in medical errors; (III) for patients: promoting health with further education and promoting primary and secondary cardiovascular health prevention. This review addresses the need for AI in cardiovascular medicine by reviewing recent literature in different cardiovascular imaging modalities: electrocardiography, echocardiography, cardiac computed tomography, cardiac nuclear imaging, and cardiac magnetic resonance (CMR) imaging as well as the role of EHR. This review aims to conceptulise these studies in relation to their clinical applications, potential limitations and future opportunities and directions.

Nuclear Imaging for the Assessment of Cardiotoxicity from Chemotherapeutic Agents in Oncologic Disease.

In this review, we summarize the major known cardiac toxicities of common chemotherapeutic agents and the role of nuclear cardiac imaging for the surveillance and assessment of cancer therapeutics-related cardiac dysfunction in routine clinical practice. Cardiotoxicity from chemotherapy causes a significant mortality and limits potentially life-saving treatment in cancer patients. Close monitoring of cardiac function during chemotherapy is an accepted method for reducing these adverse effects especially in patients with cancer therapeutics-related cardiac dysfunction. Nuclear imaging is a sensitive, specific, and highly reproducible modality for assessment of cardiac function. Nuclear imaging techniques including equilibrium radio nucleotide angiography, myocardial perfusion imaging, and novel experimental molecular imaging are the various objective tools available in addition to conventional echocardiography and cardiac magnetic resonance imaging in the surveillance, assessment, and follow-up of cancer therapeutics-related cardiac dysfunction.

The role of myocardial innervation imaging in different clinical scenarios: an expert document of the European Association of Cardiovascular Imaging and Cardiovascular Committee of the European Association of Nuclear Medicine.

Cardiac sympathetic activity plays a key role in supporting cardiac function in both health and disease conditions, and nuclear cardiac imaging has always represented the only way for the non-invasive evaluation of the functional integrity of cardiac sympathetic terminals, mainly through the use of radiopharmaceuticals that are analogues of norepinephrine and, in particular, with the use of 123I-mIBG imaging. This technique demonstrates the presence of cardiac sympathetic dysfunction in different cardiac pathologies, linking the severity of sympathetic nervous system impairment to adverse patient's prognosis. This article will outline the state-of-the-art of cardiac 123I-mIBG imaging and define the value and clinical applications in the different fields of cardiovascular diseases.

Recent Trends and Potential Drivers of Non-invasive Cardiovascular Imaging Use in the United States of America and England.

Background: Non-invasive Cardiovascular imaging (NICI), including cardiovascular magnetic resonance (CMR) imaging provides important information to guide the management of patients with cardiovascular conditions. Current rates of NICI use and potential policy determinants in the United States of America (US) and England remain unexplored.Methods: We compared NICI activity in the US (Medicare fee-for-service, 2011–2015) and England (National Health Service, 2012–2016). We reviewed recommendations related to CMR from Clinical Practice Guidelines, Appropriate Use Criteria (AUC), and Choosing Wisely. We then categorized recommendations according to whether CMR was the only recommended NICI technique (substitutable indications). Reimbursement policies in both settings were systematically collated and reviewed using publicly available information.Results: The 2015 rate of NICI activity in the US was 3.1 times higher than in England (31,055 vs. 9,916 per 100,000 beneficiaries). The proportion of CMR of all NICI was small in both jurisdictions, but nuclear cardiac imaging was more frequent in the US in absolute and relative terms. American and European CPGs were similar, both in terms of number of recommendations and proportions of indications where CMR was not the only recommended NICI technique (substitutable indications). Reimbursement schemes for NICI activity differed for physicians and hospitals between the two settings.Conclusions: Fee-for-service physician compensation in the US for NICI may contribute to higher NICI activity compared to England where physicians are salaried. Reimbursement arrangements for the performance of the test may contribute to the higher proportion of nuclear cardiac imaging out of the total NICI activity. Differences in CPG recommendations appear not to explain the variation in NICI activity between the US and England.