Field Of Nuclear Cardiology Research Articles

Artificial Intelligence Empowered Nuclear Medicine and Molecular Imaging in Cardiology: A State-of-the-Art Review.

Nuclear medicine and molecular imaging plays a significant role in the detection and management of cardiovascular disease (CVD). With recent advancements in computer power and the availability of digital archives, artificial intelligence (AI) is rapidly gaining traction in the field of medical imaging, including nuclear medicine and molecular imaging. However, the complex and time-consuming workflow and interpretation involved in nuclear medicine and molecular imaging, limit their extensive utilization in clinical practice. To address this challenge, AI has emerged as a fundamental tool for enhancing the role of nuclear medicine and molecular imaging. It has shown promising applications in various crucial aspects of nuclear cardiology, such as optimizing imaging protocols, facilitating data processing, aiding in CVD diagnosis, risk classification and prognosis. In this review paper, we will introduce the key concepts of AI and provide an overview of its current progress in the field of nuclear cardiology. In addition, we will discuss future perspectives for AI in this domain.

Hot spot imaging in cardiovascular diseases: an information statement from SNMMI, ASNC, and EANM

This information statement from the Society of Nuclear Medicine and Molecular Imaging, American Society of Nuclear Cardiology, and European Association of Nuclear Medicine describes the performance, interpretation, and reporting of hot spot imaging in nuclear cardiology. The field of nuclear cardiology has historically focused on cold spot imaging for the interpretation of myocardial ischemia and infarction. Hot spot imaging has been an important part of nuclear medicine, particularly for oncology or infection indications, and the use of hot spot imaging in nuclear cardiology continues to expand. This document focuses on image acquisition and processing, methods of quantification, indications, protocols, and reporting of hot spot imaging. Indications discussed include myocardial viability, myocardial inflammation, device or valve infection, large vessel vasculitis, valve calcification and vulnerable plaques, and cardiac amyloidosis. This document contextualizes the foundations of image quantification and highlights reporting in each indication for the cardiac nuclear imager.

Hot Spot Imaging in Cardiovascular Diseases: An Information Statement from SNMMI, ASNC, and EANM.

This information statement from the Society of Nuclear Medicine and Molecular Imaging, American Society of Nuclear Cardiology, and European Association of Nuclear Medicine describes the performance, interpretation, and reporting of hot spot imaging in nuclear cardiology. The field of nuclear cardiology has historically focused on cold spot imaging for the interpretation of myocardial ischemia and infarction. Hot spot imaging has been an important part of nuclear medicine, particularly for oncology or infection indications, and the use of hot spot imaging in nuclear cardiology continues to expand. This document focuses on image acquisition and processing, methods of quantification, indications, protocols, and reporting of hot spot imaging. Indications discussed include myocardial viability, myocardial inflammation, device or valve infection, large vessel vasculitis, valve calcification and vulnerable plaques, and cardiac amyloidosis. This document contextualizes the foundations of image quantification and highlights reporting in each indication for the cardiac nuclear imager.

Inter-reader variability of SPECT MPI readings in low- and middle-income countries: Results from the IAEA-MPI Audit Project (I-MAP)

BackgroundConsistency of results between different readers is an important issue in medical imaging, as it affects portability of results between institutions and may affect patient care. The International Atomic Energy Agency (IAEA) in pursuing its mission of fostering peaceful applications of nuclear technologies has supported several training activities in the field of nuclear cardiology (NC) and SPECT myocardial perfusion imaging (MPI) in particular. The aim of this study was to verify the outcome of those activities through an international clinical audit on MPI where participants were requested to report on studies distributed from a core lab. MethodsThe study was run in two phases: in phase 1, SPECT MPI studies were distributed as raw data and full processing was requested as per local practice. In phase 2, images from studies pre-processed at the core lab were distributed. Data to be reported included summed stress score (SSS); summed rest score (SRS); summed difference score (SDS); left ventricular (LV) ejection fraction (EF) and end- diastolic volume (EDV). Qualitative appraisals included the assessment of perfusion and presence of ischemia, scar or mixed patterns, presence of transient ischemic dilation (TID), and risk for cardiac events (CE). Twenty-four previous trainees from low- and middle-income countries participated (core participants group) and their results were assessed for inter-observer variability in each of the two phases, and for changes between phases. The same evaluations were performed for a group of eleven international experts (experts group). Results were also compared between the groups. ResultsExpert readers showed an excellent level of agreement for all parameters in both phase 1 and 2. For core participants, the concordance of all parameters in phase 1 was rated as good to excellent. Two parameters which were re-evaluated in phase 2, namely SSS and SRS, showed an increased level of concordance, up to excellent in both cases. Reporting of categorical variables by expert readers remained almost unchanged between the two phases, while core participants showed an increase in phase 2. Finally, pooled LVEF values did not show a significant difference between core participants and experts. However, significant differences were found between LVEF values obtained using different software packages for cardiac analysis. ConclusionsIn this study, inter-observer agreement was moderate-to-good for core group readers and good-to-excellent for expert readers. The quality of reporting is affected by the quality of processing. These results confirm the important role of the IAEA training activities in improving imaging in low- and middle-income countries.

Determination of radiation dose from patients undergoing Tc-99m Sestamibi nuclear cardiac imaging

To date, myocardial perfusion (MP) has been utilized to assess the adequacy of blood flow to the myocardium in order to determine the ischemic heart diseases. With the advent of SPECT/CT, MP became the most common investigation in the field of nuclear cardiology with more accuracy and details. Thallium-201 and Technetium-99m (Tc-99m) have been early used in cardiac nuclear imaging. Half-life of Tc-99m is 6 h, and its energy is 140 keV, while the half-life of Tl-201 is as longer as 73 h, its X-ray energies range between 69 and 81 kV in addition to gamma rays of 135 keV and 167 keV. The purpose of the present study was to explore the radiation dose rates emitted from the patients following Tc-99m sestamibi injection. To achieve that, the radiation emanated to the environment was measured at different distances from patients and various time intervals for 20 patients using GM counter. The mean radioactivity administered to the patients was 391.1 MBq (10.6 mCi), with a range between 276.8 MBq to maximum of 515.4 MBq. Radiation dose rate was found 9.07 μSv h−1 at 1 m distance from the patient’s chest level after 7.6 min, then decayed to 7.93 μSv h−1 after 36.5 min, and 7.83 μSv h−1 later to 66.4 min. It was concluded that 1 m distance from the patients sounds sensibly adequate to maintain the occupational dose within the safe limit following Tc-99m sestamibi injection, while verification of public dose rate ≤ 1 μSv h−1 at 1 m distance from the patient prolongs to 14 h following Tc-99m injection.

Nuclear Cardiology: Are We Using the Right Protocols and Tracers the Right Way?

The field of nuclear cardiology has changed considerably over recent years, with greater attention paid to safety and radiation protection issues. The wider usage of technetium-99m (Tc-99m)-labeled radiopharmaceuticals for single-photon emission computed tomography (SPECT) imaging using gamma cameras has contributed to better quality studies and lower radiation exposure to patients. Increased availability of tracers and scanners for positron emission tomography (PET) will help further improve the quality of studies and quantify myocardial blood flow and myocardial flow reserve, thus enhancing the contribution of non-invasive imaging to the management of coronary artery disease. The introduction of new instrumentation such as solid state cameras and new software will help reduce further radiation exposure to patients undergoing nuclear cardiology studies. Results from recent studies, focused on assessing the relationship between best practices and radiation risk, provide useful insights on simple measures to improve the safety of nuclear cardiology studies without compromising the quality of results.

Cardiovascular molecular imaging: Expanding the paradigms and parameters

Cardiovascular molecular imaging: Expanding the paradigms and parameters

Improving Nuclear Cardiology Practice

In the past few years there have been a number of procedural and technical advances in the field of Nuclear Cardiology which have helped modernize the field. Competing diagnostic modalities, concerns over medical radiation exposure, and rising health care expenditure have all played a role in fostering these new innovations. This article attempts to concisely review easily implemented improvements in stress protocols, upgrades in imaging hardware and software, and suggestions for the rational utilization of available resources which if implemented, can greatly improve nuclear cardiology practice.

Comment on “Analysis of the diastolic function by myocardial perfusion gated SPECT after coronary revascularization in acute myocardial infarction”

We read with great interest the manuscript entitled “Analisis de la function diastolica mediante gated-SPECT de perfusion miocardica tras revascularizacion coronaria en el infarto agudo de miocardio” [Analysis of the diastolic function by myocardial perfusion gated SPECT after coronary revascularization in acute myocardial infarction] by Romero-Farina et al. in the first issue of 2013 of Rev Esp Med Nucl Imagen.1 They should be congratulated for the article which is drawing attention to the important field of nuclear cardiology. With the present communication, we would like to contribute a technical detail regarding this issue. Authors analyzed the diastolic function by myocardial perfusion gated SPECT after coronary revascularization in acute myocardial infarction. Significant improvement in diastolic function has been reported mainly associated to the amount of salvage myocardium afterpercutaneous coronary revascularization inpatientwith acute myocardial infarction. They acquired the gated SPECT images by dividing the R–R interval to 8 frames and the results of the time to peak filling rate (TTPF) and peak filling rate (PFR) was obtained by the software using this data. It has been recommended that

Tomographic Imaging Methods and Gated Technique in Nuclear Cardiology: A Review on Current Status and Future Developments

Cardiac applications of SPECT or PET imaging and Gated technique have a wide area of use in the field of nuclear cardiology. Throughout the last decade, rapid technological developments have occurred, and additional contributions to the patient administration and the cost-effectiveness of these radionuclide imaging methods have been shown. Regarding single or hybride cardiac imaging, including SPECT and PET methods with or without ECG-gated technique in field of nuclear cardiology with an extensive review, this article presents the current status in the technical background of nuclear tomographic imaging and in the areas of clinical practice, and intends to predict future developments on related patent forms.

The origins and early years of the American Society of Nuclear Cardiology

In 1971 and 1973, Drs Strauss and Zaret published the seminal descriptions of stress radionuclide myocardial perfusion imaging and of ECG-gated blood pool imaging, marking the beginning of what we know now as nuclear cardiology. In the later years (1975-1980), radionuclide cardiac imaging emerged as a distinct entity within the field of nuclear medicine. The publication by Dr Gould on pharmacologic stress perfusion imaging was also pivotal for the development of this field. Of relevance for later developments, it was predominantly cardiologists who investigated and introduced the use of nuclear medicine techniques for clinical imaging of the heart. At the national meetings of the American College of Cardiology (ACC) and the American Heart Association (AHA), an increasing number of scientific sessions were devoted to clinical applications of radionuclide cardiac imaging. However, the daylong symposium on cardiovascular imaging at the annual meeting of the Society of Nuclear Medicine (SNM) became the most important annual educational and scientific event for those involved in nuclear cardiac imaging. The increasing interest in Nuclear Cardiology led to the formation of the Cardiovascular (CV) Council of the SNM on November 12, 1985. Dr Elias Botvinick was the founder and the first president, who was joined by a small core group of mainly cardiologists. Subsequent presidents were all prominent investigators in the field of nuclear cardiology, and many of them were cardiologists (Table 1). With 1,012 members, the CV Council became the most dynamic and largest council of the SNM. Thirty-six percent of the members were nuclear physicians, 32% cardiologists, 22% technologists, and 10% representatives of industry. Nevertheless, cardiologists were the predominant forces within the CV Council with regard to educational and research activities. After several years of very successful and wellattended cardiovascular imaging symposia, many cardiac imaging investigators felt that nuclear cardiology should expand as a field on its own and become more widely inclusive to those physicians who were becoming interested in this area of medicine. Early attempts to develop this concept within the SNM were not very successful. The leadership of the SNM exercised their official power to limit the operation of the CV Council as a mainly educational activity for its own nuclear medicine community and obviously had no desire to initiate a separate and potentially independent professional society within its own ranks. To many of the members of the CV Council, it became increasingly clear that a more effective and likely independent representation might be needed to advance the field. It was also recognized that such an effort should include clear guidelines for clinical training and practice that would lead to more consistent quality of nuclear cardiology services. The lack of such standards and the perception that there was wide variation in the field of nuclear cardiology practice was felt to significantly harm its credibility.

The frontiers of nuclear cardiology research

The frontiers of nuclear cardiology research

Atlas of Nuclear Cardiology: Imaging Companion to Braunwald’s Heart DiseaseAmi E. Iskandrian, MD, MACC, FASNC, FAHA, and Ernest V. Garcia, PhD, FASNC, FAHA, eds 453 pages. Philadelphia, PA: Elsevier Saunders; 2012. $179.00. ISBN: 978-1-4160-6134-2

Ami E. Iskandrian, MD, MACC, FASNC, FAHA, and Ernest V. Garcia, PhD, FASNC, FAHA, eds 453 pages. Philadelphia, PA: Elsevier Saunders; 2012. $179.00. ISBN: 978-1-4160-6134-2 The main purpose of an atlas devoted to a cardiac imaging technology is to teach using clinical images from real patients with accompanying text of a didactic nature. For an imaging technology, a comprehensive and well-illustrated atlas is a welcome contribution to teaching the principles and fine points of image analysis, diagnostic interpretation, and reporting. In this outstanding Atlas of Nuclear Cardiology , Iskandrian and Garcia and the other contributing authors successfully achieve the major goals of highly effective teaching via use of clinical images and accompanying text. The text of each chapter starts with a pertinent background section and ends with a Comments paragraph and Selected Readings, comprising references as current as 2011. This volume is intended to serve as a companion to Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine . It contains high-quality radionuclide images related to typical clinical cases encountered in cardiology. The color scale employed for the perfusion images, which ranges from yellow to orange to blue, is excellent and is the standard for the field. All of the contributors are well-recognized experts in the field of nuclear cardiology and provide the reader with a compendium of all major clinical applications of radionuclide imaging. A positive feature of each chapter is the bulleted list of Key Points. These are set right after the title of the chapter and serve to guide the reader to the main teaching points …

Imagerie: scintigraphie myocardique ou IRM ?

Hybrid imaging devices including PET/CT and SPECT/CT have seen a great success in clinical routine, especially in the field of oncology. With the recent advent of PET/MRI scanners, expectations that PET/MRI would replicate that success were accordingly high. The combination of molecular imaging with a variety of very specific PET tracers and the high spatial resolution of MRI are expected to result in increased diagnostic accuracy or even in the creation of additional demands for hybrid imaging. However, as these systems have entered the market just recently, experience in the field of nuclear cardiology is limited and some applications still need to be validated. Owing to the profound technical differences between CT and MRI, which influences not only the estimation of the photon attenuation but also causes marked differences in the workflow, particularly in cardiovascular studies (such as the need for special personnel training and interaction between nuclear medicine specialists, radiologists, and physicists), the “familiarization phase” with this new technique also seems to be extended. However, the approach to study various conditions such as perfusion, viability, and atherosclerosis in a single imaging examination session using PET and MRI offers advantages. Although MRI allows for a detailed morphologic characterization of the studied tissue, PET adds the information on functional biological markers that are not (or at least not fully) measurable by MRI. Thus, this combined imaging approach will prove valuable in distinct cardiac diseases (such as myocarditis and cardiac sarcoidosis) and will offer vast research opportunities.

Myocardial perfusion single photon computed tomography: An Atlas

The purpose of this Teaching Atlas is to provide the reader with both image recognition and an understanding of the basis for myocardial perfusion single photon computed tomography (SPECT) images interpretation. The objective is to present a wide variety of myocardial perfusion cases, both relevant and to some extent in-depth, to be used by nuclear cardiologist/nuclear medicine physicians as well as trainees in cardiology, radiology and nuclear medicine. In recent years, the field of nuclear cardiology has made major advances in both radiopharmaceuticals and instrumentation. Attenuation correction techniques have and will continue to improve the diagnostic accuracy of myocardial perfusion SPECT. Several attenuation correction aspects are included in this Atlas.

The emerging role of the selective A2A agonist in pharmacologic stress testing

Since its inception almost 50 years ago, the technique of myocardial perfusion imaging has evolved substantially. From pyrophosphate to Tl-201 to technetium-based radiotracers, from static planar imaging to gated SPECT with attenuation correction, the field of nuclear cardiology has matured with these significant technical advances. Similarly, the use of pharmacologic stressors as an alternative to exercise has also been in a state of evolution, from dipyridamole and dobutamine to adenosine, to a novel agent recently approved and available for use. This review will highlight recent developments in pharmacologic stress myocardial perfusion imaging focusing on the clinical application of the selective adenosine A2A receptor agonists.

Positron emission tomography myocardial perfusion imaging for the detection of atherosclerosis

Clinically indicated radionuclide myocardial perfusion imaging most often is performed using single photon emission CT (SPECT). Its major strengths include an extensive knowledge base attesting to its diagnostic accuracy and ability to stratify risk of short-term events, and the wide availability of instrumentation. However, it is not accurate for detecting subclinical coronary artery disease (CAD), it can seriously underestimate CAD extent, and it performs better in patients who are able to exercise. Myocardial perfusion positron emission tomography (PET) is an option that is being increasingly used for more challenging patients, especially those who need to be stressed pharmacologically. The current evidence base is small, with most work concentrated on exploring how PET data may expand the field of nuclear cardiology, rather than comparing it with SPECT. A few capabilities unique to PET include potential of routine quantitation of myocardial blood flow, assessment of peak stress rather than post-stress left ventricular function, and superior compensation for scattered counts.

Effects of adenosine A2A receptor low affinity agonist Regadenoson in patients with obstructive pulmonary disease, at risk for adenosine-induced bronchoconstriction mediated via A2B and/or A3 adenosine receptors.

The pharmaceutical Regadenoson (Lexiscan TM ) Produced by Astellas Inc. Is currently in use as a pharmacological stress agent for myocardial perfusion imaging within the field of Nuclear Cardiology. Regadenoson is a selective A 2A adenosine receptor agonist, and also has a low affinity for adenosine receptors which cause bronchoconstriction in patients with reactive airways mediated via A 2B and A3 adenosine receptors. In a study of 42 patients with mild to moderate asthma and/or moderate to severe COPD who had a positive adenosine monophosphate test, Regadenoson proved to be relatively safe and well tolerated by most patients (90%). 8 Regadenoson is a low affinity agonist (Ki H 1.3 µM) for the A2A adenosine receptor, with at least 10-fold lower affinity for the A1 adenosine receptor (Ki > 16.5 µM), and weak, if any, affinity for the A2B and A3 adenosine receptors. 2,9 Activation of the A2A adenosine receptor by regadenoson produces coronary vasodilation 8 and increases coronary blood flow (CBF). It

Clinical Myocardial Perfusion PET/CT

The field of nuclear cardiology is witnessing growing interest in the use of cardiac PET for the evaluation of patients with coronary artery disease (CAD). The available evidence suggests that myocardial perfusion PET provides an accurate means for diagnosing obstructive CAD, which appears superior to SPECT especially in the obese and in those undergoing pharmacologic stress. The ability to record changes in left ventricular function from rest to peak stress and to quantify myocardial perfusion (in mL/min/g of tissue) provides an added advantage over SPECT for evaluating multivessel CAD. There is growing and consistent evidence that gated myocardial perfusion PET also provides clinically useful risk stratification. Although the introduction of hybrid PET/CT technology offers the exciting possibility of assessing the extent of anatomic CAD (CT coronary angiography) and its functional consequences (ischemic burden) in the same setting, there are technical challenges in the implementation of CT-based transmission imaging for attenuation correction. Nonetheless, this integrated platform for assessing anatomy and biology offers a great potential for translating advances in molecularly targeted imaging into humans.

Coronary Artery Disease

Early and accurate diagnostic testing is a critical factor in the detection and optimal management of coronary artery disease (CAD); thus, noninvasive cardiac imaging has become a central tool for CAD evaluation. Currently, tests used for evaluating CAD include conventional resting and stress electrocardiogram, echocardiography, and myocardial perfusion imaging--the most widely used imaging test for evaluation of suspected myocardial ischemia. Emerging techniques for noninvasive assessment of myocardial perfusion and coronary angiography include cardiac computed tomography, cardiac magnetic resonance imaging, and positron emission tomography. The distinctive pathophysiology of atherosclerosis can be used together with imaging techniques to diagnose and assess risk for CAD. Imaging modalities for cardiac risk stratification include a diverse array of tools, such as noninvasive tests that visualize presymptomatic atherosclerosis to sophisticated radionuclide protocols that identify myocardial viability. Of the noninvasive imaging tests, gated SPECT is the most accurate method for risk stratification of CAD. Myocardial perfusion imaging with SPECT has improved accuracy and image quality such that a shift from diagnostic to prognostic use has occurred. Radionuclide myocardial perfusion imaging has played an important role in CAD evaluation since the introduction of thallium-201 (Tl-201) in the 1970s. Although Tl-201 has high sensitivity, specificity, and reproducibility, it also has physical properties that limit its use and affect image quality. Currently, Tc-99m tetrofosmin and sestamibi are the most commonly used agents for a variety of resting and stress protocols, both have similar diagnostic accuracy profiles. The field of nuclear cardiology has grown steadily over the past few decades, as more practitioners recognize its clinical applications and value in managing cardiovascular disease. There is abroad spectrum of noninvasive and invasive testing available for the diagnosis and management of patients with cardiovascular disease. Advances in computer technology have made sophisticated devices, such as the gated SPECT, a routine part of cardiology.