A New Approach in Risk Stratification by Coronary CT Angiography.

For a decade, coronary computed tomographic angiography (CCTA) has been used as a promising noninvasive modality for the assessment of coronary artery disease (CAD) as well as cardiovascular risks. CCTA can provide more information incorporating the presence, extent, and severity of CAD; coronary plaque burden; and characteristics that highly correlate with those on invasive coronary angiography. Moreover, recent techniques of CCTA allow assessing hemodynamic significance of CAD. CCTA may be potentially used as a substitute for other invasive or noninvasive modalities. This review summarizes risk stratification by anatomical and hemodynamic information of CAD, coronary plaque characteristics, and burden observed on CCTA

IAEA Atlas of Cardiac PET/CT

This open access book presents a wide portfolio of examples of positron emission tomography coupled with computer tomography (PET/CT) studies in various cardiac conditions in order to provide a rationale for the implementation of this technology in an array of clinical conditions. Cardiovascular diseases are a major contributor to premature morbidity and mortality worldwide. Low- and middle-income countries (LMICs) are particularly affected by cardiovascular diseases (CVDs), with more than 75% of all CVDs deaths occurring in these countries. For this reason, target 3.4 of the United Nations (UN) Sustainable Development Goals (SDGs) agenda aims at a 30% reduction in premature mortality due to non-communicable diseases (NCDs), which include CVDs, by 2030. Among CVDs, ischemic heart disease (IHD) plays an important role and, according to the Institute for Health Metrics and Evaluation (IHME), it was responsible for 15.96% of global deaths in 2017. Between 2000 and 2017, the number of IHD deaths worldwide increased by 0.26% per year. Several imaging tools help to non-invasively diagnose, stratify risk and guide management in cardiac disease. They include nuclear cardiology techniques, using either SPECT (single photon emission computed tomography) or PET/CT. While myocardial imaging with SPECT has been fully embraced by the cardiology community and is widely available worldwide, PET/CT introduction has been slower, due not only to its higher costs, but also to the limited availability of PET/VCT scanners, mostly utilized for oncological applications. This book is an invaluable tool for nuclear medicine physicians, cardiologists and radiologists

Rationale and design of the dual-energy computed tomography for ischemia determination compared to “gold standard” non-invasive and invasive techniques (DECIDE-Gold) : a multicenter international efficacy diagnostic study of rest-stress dual-energy computed tomography angiography with perfusion

Background: Dual-energy CT (DECT) has potential to improve myocardial perfusion for physiologic assessment of coronary artery disease (CAD). Diagnostic performance of rest-stress DECT perfusion (DECTP) is unknown. Objective: DECIDE-Gold is a prospective multicenter study to evaluate the accuracy of DECT to detect hemodynamic (HD) significant CAD, as compared to fractional flow reserve (FFR) as a reference standard. Methods: Eligible participants are subjects with symptoms of CAD referred for invasive coronary angiography (ICA). Participants will undergo DECTP, which will be performed by pharmacological stress, and participants will subsequently proceed to ICA and FFR. HD-significant CAD will be defined as FFR\ua0 64\ua00.80. In those undergoing myocardial stress imaging (MPI) by positron emission tomography (PET), single photon emission computed tomography (SPECT) or cardiac magnetic resonance (CMR) imaging, ischemia will be graded by % ischemic myocardium. Blinded core laboratory interpretation will be performed for CCTA, DECTP, MPI, ICA, and FFR. Results: Primary endpoint is accuracy of DECTP to detect 651 HD-significant stenosis at the subject level when compared to FFR. Secondary and tertiary endpoints are accuracies of combinations of DECTP at the subject and vessel levels compared to FFR and MPI. Conclusion: DECIDE-Gold will determine the performance of DECTP for diagnosing ischemia

Cardiac hybrid imaging

Computed tomography coronary angiography (CTCA) and myocardial perfusion imaging techniques (single photon emission computed tomography, SPECT, or positron emission tomography, PET) are established non-invasive modalities for the diagnosis of coronary artery disease (CAD). Cardiac hybrid imaging consists of the combination (or ‘fusion') of both modalities and allows obtaining complementary morphological (coronary anatomy, stenoses) and functional (myocardial perfusion) information in a single setting. However, hybrid cardiac imaging has also generated controversy with regard to which patients should undergo such integrated examinations for clinical effectiveness and minimization of costs and radiation dose. The feasibility and clinical value of hybrid imaging has been documented in small cohort studies and selected series of patients. Hybrid imaging appears to offer superior diagnostic and prognostic information compared with stand-alone or side-by-side interpretation of data sets. Particularly in patients with multivessel disease, the hybrid approach allows identification of flow-limiting coronary lesions and thereby provides useful information for the planning of revascularization procedures. Furthermore, integration of the detailed anatomical information from CTCA with the high molecular sensitivity of SPECT and PET may be useful to evaluate targeted molecular and cellular abnormalities in the future. While currently still restricted to specialized cardiac centres, the ongoing efforts to reduce radiation exposure and the increasing clinical interest will further pave the way for an increasing use of cardiac hybrid imaging in clinical practic

Novel Imaging Approaches for the Detection of Hemodynamically Significant Coronary Artery Disease: Quantitative Flow Ratio and Artificial Intelligence-Based Ischemia Algorithm

ABSTRACT In coronary artery disease (CAD), the decision on revascularization is based on the hemodynamic significance of stenoses. However, this cannot directly be determined from the first-line anatomical imaging methods coronary computed tomography angiography (CCTA) in chronic coronary syndrome (CCS) or invasive coronary angiography (ICA) in acute coronary syndrome (ACS). The aim of this thesis was to investigate the prognostic value of two novel approaches to determine functionally significant CAD according to impaired invasive fractional flow reserve (FFR) directly from CCTA in CCS and ICA in ACS. Quantitative flow ratio (QFR) is a novel computational fluid dynamic-based technique to estimate the presence of impaired FFR from biplane ICA. In this study, QFR from untreated non-culprit lesions showed incremental 5-year prognostic value for major adverse cardiac events among ST-elevation myocardial infarction patients undergoing angiography-guided complete revascularization. However, non-culprit QFR did not independently predict non-target-vessel related events prior to planned staged percutaneous coronary intervention (PCI) in ACS patients, and the study does not provide conceptual evidence that QFR could be useful to refine the timing of staged PCI on top of clinical judgement. AI-QCTischemia is an artificial intelligence-based method to predict the probability of an impaired invasive FFR using 37 morphological features from CCTA. Among symptomatic patients with suspected CAD undergoing CCTA, AI-QCTischemia showed incremental prognostic value for the composite of death, myocardial infarction, or unstable angina pectoris throughout a median of 7 years follow-up. This risk stratification pertained especially to patients with no/non-obstructive disease. Patients with obstructive disease on CCTA were referred for downstream myocardial perfusion imaging with positron emission tomography (PET), and among those, AI-QCTischemia showed incremental risk stratification among patients with normal PET perfusion, but not among those with abnormal PET perfusion. KEYWORDS: coronary artery disease, quantitative flow ratio, coronary computed tomography angiography, artificial intelligence, prognosisTIIVISTELMÄ Sepelvaltimotaudissa revaskularisaatiopäätös perustuu hemodynaamisesti merkittävän ahtauman osoitukseen. Tätä ei voida kuitenkaan suoraan määrittää kaikilla kuvantamismenetelmillä, kuten sepelvaltimoiden tietokonetomografialla (TT) kroonisessa sepelvaltimo-oireyhtymässä tai kajoavalla angiografialla akuutissa sepelvaltimotautikohtauksessa. Tämän väitöskirjan tavoitteena oli tutkia kahden uuden sepelvaltimoahtauman hemodynaamisen merkityksen arvioimiseen käytettävän menetelmän ennusteellista arvoa: kajoavaan angiografiaan pohjautuva menetelmä akuutissa sepelvaltimotautikohtauksessa ja TT:aan pohjautuva menetelmä kroonisessa sepelvaltimo-oireyhtymässä. Kvantitatiivinen virtaussuhde (KVS) on uusi laskennalliseen virtausdynamiikkaan perustuva menetelmä, jolla kajoavaan painevaijerimittaukseen perustuvaa sydänlihas-iskemiaa pyritään arvioimaan suoraan tavanomaisista angiografiakuvista. Ei-revaskularisoidun non-culprit-ahtauman KVS:n määrityksellä osoitettiin ennusteellista lisäarvoa 5 vuoden sydän- ja verisuonitautitapahtumien suhteen ST-nousuinfarkti-potilailla, joille oli tehty angiografiaohjattu täydellinen revaskularisaatio. Non-culprit-ahtauman KVS ei kuitenkaan ennustanut kyseiseen suoneen liittyviä tapahtumia ennen suunniteltua viivästettyä non-culprit-ahtauman perkutaanista sepelvaltimotoimenpidettä, joten tämän tutkimuksen perusteella KVS ei vaikuta hyödylliseltä menetelmältä viivästetyn sepelvaltimotoimenpiteen ajoituksen optimoimiseksi. AI-QCTischemia on tekoälyyn perustuva menetelmä, jolla arvioidaan kajoavaan painevaijerimittaukseen perustuvan sydänlihasiskemian todennäköisyyttä käyttäen 37 morfologista sepelvaltimoiden TT:aan pohjautuvaa muuttujaa. Oireisilla potilailla, joille tehtiin TT-tutkimus sepelvaltimotaudin epäilyn vuoksi, AI-QCTischemia tarjosi ennusteellista lisäarvoa yhdistelmätapahtumalle (kuolema, sydäninfarkti tai epävakaa angina pectoris) 7 vuoden seurannan aikana. Tämä riskiluokittelu koski erityisesti potilaita, joilla ei todettu ahtauttavaa sepelvaltimotautia TT:ssa. Potilaat, joilla todettiin TT:n perusteella ahtauttava sepelvaltimotauti, ohjattiin sydänlihasperfuusion kuvantamiseen positroniemissiotomografialla (PET). Tässä joukossa AI-QCTischemia antoi ennusteellista lisätietoa potilailla, joilla oli normaali sydänlihasperfuusio, mutta ei niillä, joilla perfuusio oli alentunut. AVAINSANAT: sepelvaltimotauti, kvantitatiivinen virtaussuhde, tietokonetomografia, tekoäly, ennust

Coronary Angiography

In the intervening 10 years tremendous advances in the field of cardiac computed tomography have occurred. We now can legitimately claim that computed tomography angiography (CTA) of the coronary arteries is available. In the evaluation of patients with suspected coronary artery disease (CAD), many guidelines today consider CTA an alternative to stress testing. The use of CTA in primary prevention patients is more controversial in considering diagnostic test interpretation in populations with a low prevalence to disease. However the nuclear technique most frequently used by cardiologists is myocardial perfusion imaging (MPI). The combination of a nuclear camera with CTA allows for the attainment of coronary anatomic, cardiac function and MPI from one piece of equipment. PET/SPECT cameras can now assess perfusion, function, and metabolism. Assessing cardiac viability is now fairly routine with these enhancements to cardiac imaging. This issue is full of important information that every cardiologist needs to now

Advances in Cardiac Computed Tomography

Coronary cardiac computed tomography (CCTA) has seen rapid improvements in technology including hardware and postprocessing techniques that have contributed to its rapid growth and enabled it to remain in the forefront on diagnostic imaging. Important technological advances include wider detectors for greater coverage with less gantry rotation times, dual-source computed tomography (CT) with improved temporal resolution, dual-energy CT where simultaneous imaging at different energies to increase the contrast difference between different tissues enhances diagnostic accuracy, and emergence of spectral CT to enhance atherosclerotic imaging through nanoparticle technology. Software advances include iterative reconstruction methodologies to reduce noise and radiation doses, plaque imaging and quantification tools to assess plaque morphology and stenosis severity. Processing advances using computational fluid dynamics now enables the determination of fractional flow reserve (FFR). Another important advancement in CCTA physiologic imaging is CCTA perfusion imaging to detect ischemia and compares favorably with myocardial perfusion imaging and coronary angiographic stenosis. Finally, large registry studies and single-center studies have now been published assessing the incremental value of coronary calcium score, CT plaque severity of disease and have demonstrated that the CCTA carries strong prognostic value over and above traditional risk assessment in predicting adverse outcomes

IAEA Atlas of Cardiac PET/CT

This open access book presents a wide portfolio of examples of positron emission tomography coupled with computer tomography (PET/CT) studies in various cardiac conditions in order to provide a rationale for the implementation of this technology in an array of clinical conditions. Cardiovascular diseases are a major contributor to premature morbidity and mortality worldwide. Low- and middle-income countries (LMICs) are particularly affected by cardiovascular diseases (CVDs), with more than 75% of all CVDs deaths occurring in these countries. For this reason, target 3.4 of the United Nations (UN) Sustainable Development Goals (SDGs) agenda aims at a 30% reduction in premature mortality due to non-communicable diseases (NCDs), which include CVDs, by 2030. Among CVDs, ischemic heart disease (IHD) plays an important role and, according to the Institute for Health Metrics and Evaluation (IHME), it was responsible for 15.96% of global deaths in 2017. Between 2000 and 2017, the number of IHD deaths worldwide increased by 0.26% per year. Several imaging tools help to non-invasively diagnose, stratify risk and guide management in cardiac disease. They include nuclear cardiology techniques, using either SPECT (single photon emission computed tomography) or PET/CT. While myocardial imaging with SPECT has been fully embraced by the cardiology community and is widely available worldwide, PET/CT introduction has been slower, due not only to its higher costs, but also to the limited availability of PET/VCT scanners, mostly utilized for oncological applications. This book is an invaluable tool for nuclear medicine physicians, cardiologists and radiologists