Artificial Intelligence in Coronary Computed Tomography Angiography: From Anatomy to Prognosis

Future Trends in CT for Coronary Artery Disease: From Diagnosis to Prevention.

This review focuses on three key noninvasive cardiac imaging modalities-cardiac CT angiography (CTA), MRI, and PET/CT-and summarizes key publications in 2021 relevant to radiologists in clinical practice. Although this review focuses primarily on articles published in Radiology, important studies from other major journals are included to highlight "must-know" articles in the field of cardiovascular imaging. Cardiac CTA has been established as the first-line test for patients with stable chest pain and no known coronary artery disease, and its value remains central to the assessment of surgical or transcatheter aortic valve replacement. Artificial intelligence continues to evolve in a number of applications in cardiovascular disease. In cardiac MRI studies, 2021 has seen an emphasis on nonischemic cardiomyopathies, valvular heart disease, and COVID-19 disease cardiac manifestations and the authors highlight the key articles on these topics. A section featuring the increasing role of cardiac PET/CT in the assessment of cardiac sarcoidosis and prosthetic valves is also provided.

Purpose Although 18F-Fluorodeoxyglucose (18F-FDG) Positron Emission Tomography (PET) with computed tomography (CT) and cardiac computed tomography angiography (CTA) are essential tools in diagnosing prosthetic heart valve (PHV) endocarditis, the normal imaging findings in the first year after PHV implantation on 18F-FDG-PET/CT and CTA have not been studied prospectively. We prospectively assessed the perivalvular FDG uptake at different time points after aortic PHV implantation and assessed the normal imaging findings on CTA. Materials and methods Patients who had undergone uncomplicated aortic PHV implantation were included and underwent 18F-FDG PET/CT and CTA at 5(±1) weeks (group 1), 12(±2) weeks (group 2) or 52(±8) weeks (group 3) after implantation. After a preparatory diet to suppress normal myocardial glucose uptake, FDG uptake in the myocardium as well as around the PHV was scored using the Qualification Visual Score for Hypermetabolism (QVSH) as "none" (< mediastinum), "low" (> mediastinum but < liver), "intermediate" (> liver), or "high" (intense uptake) and quantitative analysis was performed with maximum Standardized Uptake Value (SUVmax) and target to background ratio (SUVratio) on standardized European Association of Nuclear Medicine Research Ltd. (EARL) reconstructions by an experienced nuclear medicine physician. CTA was analysed for image quality, artefacts and stranding of the peri-aortic fat by a cardiac radiologist. Results In total 37 patients (group 1: n = 12, group 2: n = 12, group 3: n = 13) (age 66 ± 8 years) were included. Myocardial FDG uptake was intermediate or less in 29/37 scans (78%). QVSH around the PHV was 8/12(67%) low and 4/12(33%) intermediate in group 1, 7/12(58%) low and 5/12(42%) intermediate in group 2 and 8/13(62%) low and 5/13(38%) intermediate in group 3 (p = 0.91). No scan was scored as "none" or "high". EARL SUVmax was 3.48 ± 0.57, 3.50 ± 0.59 and 3.34 ± 0.55 (mean ± SD, p = 0.77) and EARL SUVratio was 2.00 ± 0.29, 1.96 ± 0.41 and 1.71 ± 0.26 (mean ± SD, p = 0.07) for groups 1, 2 and 3, respectively. One patient in group 3 refused to undergo the additional CTA and one CTA in group 3 could not be analysed for image quality and artefacts due to techniqual difficulties. Overall CTA image quality was "good" or "excellent" with an artefact score of "virtually none" or "mild" in most cases (n = 33, 94%). Stranding of peri-aortic fat was seen in 27/35 (77%) of these patients (group 1: n = 11; group 2: n = 9; group 3: n = 7) with no signs of FDG uptake on PET/CT scan. Conclusion Baseline FDG uptake around aortic PHV at 5, 12 and 52 weeks after implantation is similar and mild in the majority of cases with an overall mean SUVmax and SUVratio of 3.44 ± 0.56 and 1.89 ± 0.34 respectively. CTA revealed baseline post-surgical findings in the first year after PHV implantation.

Cardiac CT angiography in current practice: An American society for preventive cardiology clinical practice statement✰

<i>Circulation</i> Editors’ Picks

Cardiac CT Angiography (CTA) and Nuclear Myocardial Perfusion Imaging (MPI)—A Comparison in Detecting Significant Coronary Artery Disease

Background Lifestyle and diet modification are the forefront in the management of coronary artery disease (CAD), however, there is no data whether they may stop progression of atheroslcerosis. Some coronary plaque characteristics are known to increase the risk of future cardiovascular events independently of coronary stenosis severity. These plaques are characterized by the presence of lipids and necrotic elements, and can be identified with coronary computed tomography angiography (CTA). Purpose To study the effect of intensive dietary intervention on changes in atherosclerotic plaque volume and composition. Methods We enrolled 89 patients (41% women, mean age 60±7.7 years) with nonobstructive coronary lesions (&amp;lt;70% stenosis) identified by CTA (2x192-multislice scanner, temporal resolution 66 ms), qualified to medical treatment. All participants were subjected to optimal medical therapy (OMT). Patients were randomised (1:1) to either A) OMT with regular follow-up (after 1, 3, 6, 9 and 12 months) by a dietitian to stick to Dietary Approaches to Stop Hypertension (DASH) model, or B) routine management, ie. OMT alone. CTA was repeated in all patients after the mean time of 66.9±13.7 weeks. An experienced observer blinded to the allocated treatment group and other clinical data evaluated all of the scans. The outcome was change in total plaque volume, percent plaque volume and plaque composition, assessed with a dedicated software system. Based on tissue attenuation ranges in Hounsfield units (HU), the following components of atheroma were distinguished: dense calcium (&amp;gt;351 HU), fibrous plaque (151 to 350 HU), and fibrofatty plaque plus necrotic core (−100 to 150 HU), regarded as the vulnerable plaque component. Results Total plaque volume did not change significantly in any group (p=0.41; Figure 1A). Percent atheroma volume increased in the control arm vs. no significant change in the experimental arm, with no significant intergroup difference (p=0.79; Figure 1B). Vulnerable plaque component decreased in both subgroups, by 52.9±82.2 mm3 in the experimental vs. 20.8±58.5 mm3 in the control arm, and there was a significant difference in the reductions between the groups (p=0.04; Figure 1C). Fibrous plaque volume and dense calcium volume did not change significantly in any group (+9.5±117.8 mm3 in the experimental vs. +7.6±92.1 mm3 in the control arm, p=0.93, and +33±68.9 mm3 vs. +30.2±52.5 mm3, p=0.78, respectively). Conclusions Intensive diet intervention atop OMT can stop the progression of atherosclerosis and lead to a significant reduction in vulnerable plaque component compared to OMT alone. Figure 1 Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): Institute of Cardiology in Warsaw, Poland

Background The effectiveness of aspirin (ASA) for primary prevention of major adverse cardiovascular events (MACE) in persons who smoke tobacco remains unclear, particularly among patients who underwent cardiac computed tomography angiography (CCTA) and coronary artery calcium scoring (CACS) due to suspected chronic coronary syndrome. Purpose To evaluate the risk of MACE and bleeding events across predefined CACS categories in relation to ASA use and smoking status. Methods A registry-based study of adult individuals (≥18 years of age) who underwent CCTA and CACS measurement from 2008-2022. Individuals were stratified by baseline ASA use (yes/no), CACS category (0, 1–99, 100–399, 400–999, ≥1000) and smoking status (current or prior versus no). Main exclusion criteria: history of acute coronary syndrome, coronary interventions, stroke, or treatment with ASA, anticoagulants, or P2Y12 inhibitors. The effectiveness endpoint was MACE, a composite of: death from any cause, non-fatal acute coronary syndrome, or non-fatal stroke, or revascularization. The safety endpoint was major bleeding requiring hospitalization. Follow-up began at 180 days after CCTA and ended upon event, emigration, death (for bleeding endpoint), or 2 years of follow-up, whichever came first. Absolute risks and risk differences (ASA vs no ASA) of the effectiveness and safety endpoints were computed using average treatment effect modelling with multivariable Cox regression analysis standardised to the distributions of age, sex and selected comorbidities. Results Of 65,519 included patients, 44.8% were non-smokers (25.7% used ASA), 55.2% were smokers (32.6% used ASA). Among non-smokers in lower CACS categories, no significant difference in the standardized absolute risk of MACE was observed between ASA users and non-users (all P for risk difference ≥0.05, Figure 1). ASA use was associated with a numerically lower absolute risk of MACE in patients with CACS 400-999 and ≥1000 (for 400-999: 3.5% [2.2% ; 4.7%] vs 4.6% [2.9% ; 6.3%] and for ≥1000: 4.8% [95% CI 2.8%; 6.7%] vs. 5.8% [95% CI 3.3%; 8.3%]), P=0.48. Bleeding risk did not differ significantly between ASA vs. no ASA (Figure 1). Among smokers, ASA use was not associated with a significant reduction in MACE risk across all CACS categories (all P for risk difference &amp;gt;0.05) In the CACS group ≥1000, event rates were similar between ASA users and non-users (8.8% [95% CI 6.8% ; 10.8%] vs. 8.0% [95% CI 5.8% ; 10.3%], P=0.58). Bleeding risks in the smoking group were generally higher with ASA use across all CACS levels, except for those with CACS ≥1000. In general, smokers had numerically higher MACE and bleeding risks than non-smokers (Figure 1). Conclusion ASA use for primary prevention was not associated with reduced risk of MACE across CACS categories or with a significant impact on bleeding risk in smokers and non-smokers undergoing CCTA. These findings suggest that ASA may have limited preventive effects in this population.Figure 1

To investigate the shape of right auricule on 256-slice computed tomography (CT). Five hundred people (250 men, age range 16-84years) who had cardiac multidetector CT angiography were recruited in this study. All patients had normal sinus rhythm with normal blood pressure (<140/90mmHg for systolic/diastolic pressure). The morphology of the right auricule was studied and compared after reconstruction of the raw images. All patients successfully had cardiac CT angiography (100%), and the right auricule morphology was divided into five types and nine subtypes, including Type I of triangular shape (Ia and Ib), Type II of M shape (IIa and IIb), Type III of L shape (IIIa and IIIb), Type IV of reverse L shape (IVa and IVb), and Type V of balanced shape. The most common type of right auricule is Type IV (28.4%) followed by Type II (24.0%), whereas the least common is Type V (11.0%). Type Ia was present significantly (P<0.0001) more frequently in females than in males, whereas Type IIa significantly (P=0.042) more frequently in males than females. No other significant (P>0.05) sex difference existed in the constitution ratio of the types. The normal angle was greater in Type Ib than in Ia. The greater the normal angle in Type I, the greater the deviation of the right auricule tip towards the left. A good understanding of the right auricule anatomical morphology can better guide atrial pacing, radiofrequency ablation and other surgical procedures while preventing possible intra-procedural complications.

Previous research showed a significant difference in the presence of subclinical coronary artery disease (CAD) on cardiac CT angiography (CTA) between patients with idiopathic paroxysmal atrial fibrillation (iAF) versus a matched sinus rhythm population (iSR). Here we present 5-year follow-up data and the consequences of subclinical CAD on baseline CTA on the development of cardiovascular disease in iAF. In 99 iAF patients (who underwent CTA as part of work-up for pulmonary vein isolation) and 221 matched iSR controls (who underwent CTA for CAD assessment), the incidence of hypertension, diabetes and major cardiovascular events (MACCE) during follow-up was obtained. Multivariable Cox regression analysis was used to reveal predictors of incident cardiovascular disease in the iAF group. During a follow-up of 68±11 months, over one third of patients developed cardiovascular disease, with no difference between iAF and iSR (log-rank p=0.56), and comparable low rates of MACCE (4.0% vs 5.0%,p=0.71). Within the iAF group, age (HR1.12(1.03-1.20);p=0.006), left atrial diameter (HR1.16(1.03-1.31);p=0.01), Segment Involvement Score (total number of coronary segments with atherosclerotic plaque; HR1.43(1.09-1.89);p=0.01) and the number of calcified plaques on CTA (HR0.53(0.30-0.92);p=0.01) were independent predictors of incident cardiovascular disease. Subclinical coronary disease on CTA may be useful to identify the subset of patients with iAF that harbour concealed cardiovascular risk factors and need intensive clinical follow-up to ensure timely initiation of appropriate therapy once CV disease develops, including anticoagulation and vascular prophylactic therapy.

Bailout intravenous esmolol for heart rate control in cardiac computed tomography angiography

Impact of a Reduced Tube Voltage on CT Angiography and Radiation Dose: Results of the PROTECTION I Study

Association of ischemic stroke to coronary artery disease using computed tomography coronary angiography

Background The AI-based CariHeart Risk calculator has been developed using cardiac CT angiography (CCTA) assessment of the peri-coronary artery inflammation (FAI) and conventional cardiovascular risk factors to predict 8 years fatal and non-fatal cardiovascular events. As one of the 5 chosen Hospitals in the United Kingdom we have performed and interim analysis to assess the impact of the proposed new chest pain pathway on the risk stratification of patients referred for suspected angina to the Rapid Access Chest Pain Clinic (RACPC). Objective We set out to investigate the interaction (risk stratification predictive power) between the degree of coronary artery disease (CAD), the FAI risk score and the AI-based CariHeart Risk score. Methods 135 consecutive patients referred to the RACPC are part of this analysis. 2 patients had no contrast CCTA images at patient request and were excluded. Risk stratification was defined as no or mild CAD (&amp;lt;50% stenosis), moderate, (50-69% stenosis), severe (&amp;gt;70% stenosis) based on the degree or coronary artery luminal stenosis, low FAI score defined less then 50 percentile for any coronary artery, intermediate FAI score defined 50-75 percentile for LAD/RCA or 50-90 percentile for LCX, and high FAI score defined &amp;gt;75 percentile for LAD/RCA and &amp;gt;90 percentile for LCX. Low AI- CariHeart risk score was defined &amp;lt;1% 8 years CV mortality, intermediate risk 1-5% CV mortality, and high risk if &amp;gt;5% CV mortality. Results We found that patients with No or mild atherosclerotic CAD had a low FAI score in 4/114 (3.5%), intermediate score in 16/114 (14%), and high score in 94/114 (82%), (p&amp;lt;0.00001). Low CariHeart risk score was found in 4 (3.6%), intermediate risk score in 47 (41%), and high-risk score in 63 (55%) (p&amp;lt;0.0001). In No-or mild CAD patients the FAI score identified larger number of patients then CariHeart risk score as high risk 82% vs 55%, p&amp;lt;0.0001. However, merging the intermediate and high FAI score patients and compare it with the merged intermediate and high CariHeart risk score patients the two scores identified the same proportion of patients 97%. The 13 patients with moderate CAD on CCTA, low FAI score was found in none, intermediate score in 38%, and high score in 62%, (p=0.025). Low CariHeart risk score was found in none, intermediate risk score in 8%, and high-risk score in 92%, (p&amp;lt;0.007). High FAI score was found in all 3 cases whereas high CariHeart score in 2 cases and intermediate in 1 with severe CAD on CCTA. Conclusion The AI-based new chest pain pathway utilising CCTA images has identified higher proportion of at-risk patients particularly those with non-obstructive CAD. FAI score and CariHeart risk score seems to perform similarly in the aggregate intermediate and high-risk groups. To assess the value of the NP on real world outcome and the effect of new and conventional cardiovascular preventative therapy is warranted.

Background:Identifying cardioembolic sources in patients with acute ischemic stroke is important for the choice of secondary prevention strategies. We prospectively investigated the yield of admission (spectral) nongated cardiac computed tomography angiography (CTA) to detect cardioembolic sources in stroke.Methods:Participants of the ENCLOSE study (Improved Prediction of Recurrent Stroke and Detection of Small Volume Stroke) with transient ischemic attack or acute ischemic stroke with assessable nongated head-to-heart CTA at the University Medical Center Utrecht were included between June 2017 and March 2022. The presence of cardiac thrombus on cardiac CTA was based on a Likert scale and dichotomized into certainly or probably absent versus possibly, probably, or certainly present. The diagnostic certainty of cardiac thrombus was evaluated again on spectral computed tomography reconstructions. The likelihood of a cardioembolic source was determined post hoc by an expert panel in patients with cardiac thrombus on CTA. Parametric and nonparametric tests were used to compare the outcome groups.Results:Forty four (12%) of 370 included patients had a cardiac thrombus on admission CTA: 35 (9%) in the left atrial appendage and 14 (4%) in the left ventricle. Patients with cardiac thrombus had more severe strokes (median National Institutes of Health Stroke Scale score, 10 versus 4; P=0.006), had higher clot burden (median clot burden score, 9 versus 10; P=0.004), and underwent endovascular treatment more often (43% versus 20%; P<0.001) than patients without cardiac thrombus. Left atrial appendage thrombus was present in 28% and 6% of the patients with and without atrial fibrillation, respectively (P<0.001). The diagnostic certainty for left atrial appendage thrombus was higher for spectral iodine maps compared with the conventional CTA (P<0.001). The presence of cardiac thrombus on CTA increased the likelihood of a cardioembolic source according to the expert panel (P<0.001).Conclusions:Extending the stroke CTA to cover the heart increases the chance of detecting cardiac thrombi and helps to identify cardioembolic sources in the acute stage of ischemic stroke with more certainty. Spectral iodine maps provide additional value for detecting left atrial appendage thrombus.Registration:URL: https://www.clinicaltrials.gov; Unique identifier: NCT04019483.