Cardiac Computed Tomography Angiography Research Articles

Comparison between Cardiac CTA and Echocardiography for Assessment of Ventricular Septal Rupture Diameter and Its Effect on Transcatheter Closure.

This study is aimed at comparing cardiac computed tomographic angiography (CTA) with echocardiography in the assessment of ventricular septal perforation diameter. A total of 44 ventricular septal rupture (VSR) patients undertaking transcatheter occlusion were included and randomly divided into the CTA group and echocardiography group with a 1 : 1 ratio. Clinical data, operation-related data, and 30 d follow-up data were collected and analyzed. Incidence of closure failure, occluder displacement, poor occluder molding, and occluder waist diameter shrinkage between the two groups were not statistically different. The mean residual shunt volume in the echocardiography group (4.2 (3.1, 5.9) mm) was significantly higher than that in the CTA group (2.1 (0, 4.0) mm) with a p value of 0.005. However, no significant differences were found in all-cause mortality and incidence of operative complications within 30 days after surgery. Within the CTA group, the correlation was strongest between postoperative occluder diameter and long diameter measured by CTA with a correlation coefficient of 0.799 and p < 0.001, followed by the correlation between postoperative occluder diameter and mean diameter measured by CTA with a correlation coefficient of 0.740 and p < 0.001. The diameter measured by echocardiography was not correlated to postoperative occlude diameter. Assessment of VSR diameter by cardiac CTA is more accurate than by echocardiography.

Regional left ventricle scar detection from routine cardiac computed tomography angiograms using latent space classification

Objectives:The aim of this study is to develop an automated method of regional scar detection on clinically standard computed tomography angiography (CTA) using encoder–decoder networks with latent space classification. Background:Localising scar in cardiac patients can assist in diagnosis and guide interventions. Magnetic resonance imaging (MRI) with late gadolinium enhancement (LGE) is the clinical gold standard for scar imaging; however, it is commonly contraindicated. CTA is an alternative imaging modality that has fewer contraindications and is widely used as a first-line imaging modality of cardiac applications. Methods:A dataset of 79 patients with both clinically indicated MRI LGE and subsequent CTA scans was used to train and validate networks to classify septal and lateral scar presence within short axis left ventricle slices. Two designs of encoder–decoder networks were compared, with one encoding anatomical shape in the latent space. Ground truth was established by segmenting scar in MRI LGE and registering this to the CTA images. Short axis slices were taken from the CTA, which served as the input to the networks. An independent external set of 22 cases (27% the size of the cross-validation set) was used to test the best network. Results:A network classifying lateral scar only achieved an area under ROC curve of 0.75, with a sensitivity of 0.79 and specificity of 0.62 on the independent test set. The results of septal scar classification were poor (AUC < 0.6) for all networks. This was likely due to a high class imbalance. The highest AUC network encoded anatomical shape information in the network latent space, indicating it was important for the successful classification of lateral scar. Conclusions:Automatic lateral wall scar detection can be performed from a routine cardiac CTA with reasonable accuracy, without any scar specific imaging. This requires only a single acquisition in the cardiac cycle. In a clinical setting, this could be useful for pre-procedure planning, especially where MRI is contraindicated. Further work with more septal scar present is warranted to improve the usefulness of this approach.

Normal indexed values of left atrial volume by age and gender in a population of 250 healthy subjects: a CT-study

Abstract Introduction Left atrial volume (LAV) is predictive of cardiovascular outcomes. Its reference values have been described with 2D-transthoracic echocardiography (TTE) and cardiac MRI but very few data are published regarding cardiac computed tomography angiography (CCTA) values. Recent guidelines have highlighted the role of CT-scan, which is a valuable tool to evaluate cardiac dimensions, by its volumetric approach, with a minimal time acquisition and high reproducibility. Purpose We aimed to provide CCTA normal LAV reference values by age and gender in a population of 250 healthy subjects. Methods We retrospectively included 250 adults (18–74 years) who underwent a retrospectively ECG-gated CCTA in our institution, in order to rule out coronary disease after an episode of chest pain, without any history of cardiac disease or anomaly on the CT-scan. We divided our population in 5 classes of age (&amp;lt;40; 40–49; 50–59; 60–69; ≥70 years) with 1:1 sex ratio. LAV was evaluated at 40% of RR cycle, corresponding to maximal volume, by 2 different methods: semi-automated volumetric approach (3D) and manual area-length (A-L), as recommended for echocardiography and MRI. Results In the overall population, mean LAV was 50.6±12.7 ml/m2 (lower and upper limits 25 and 76 ml/m2 respectively) by 3D method and slightly lower using A-L method (42.8±11.5 ml/m2) (LL and UL 20 and 66 ml/m2 respectively). Normal values were 22–81 ml/m2 (3D) and 17–68 ml/m2 (A-L) in men and 30–70 ml/m2 (3D) and 23–63 ml/m2 (A-L) in women. There was no significant difference across genders, but LAV significantly increased with age by the 2 methods (Table 1). Interobserver agreement was better using 3D than A-L method (Lin's coefficient = 0.89 and 0.67, respectively). Concordance between the 2 methods was good, with overall Pearson's correlation coefficient R = 0.72 (p&amp;lt;0.001) (Figure 1). Conclusion This study is the first to establish normal indexed LAV values by gender and age in a large population of healthy adults with 2 methods, 3D volumetric approach being the most reproducible one. More accurate than TTE and more available than CMR, CCTA may become a reference method to evaluate LAV in various cardiac diseases and normal values definition is thus of importance. Funding Acknowledgement Type of funding sources: None.

Development and validation of non-invasive endothelial shear stress (ESS) estimations of coronary artery haemodynamics using computational modelling

Abstract Background Vascular remodelling is influenced by various biomechanical forces such as endothelial shear stress (ESS) and is associated with development and progression of coronary artery disease (CAD). ESS is the parallel frictional force exerted by blood flow on the endothelial luminal surface of the arterial wall. While ESS may not be the only cause of atherosclerosis, it is postulated that low ESS creates a pro-atherogenic environment and high ESS is athero-protective. Computational fluid dynamics (CFD) is an engineering method used to analyse fluid flow and has been increasingly applied to simulate ESS in cardiovascular research. However, current CFD-derived ESS estimates have never been validated and can display significant variability between research groups. Purpose This study aims to provide a comparative analysis of coronary flow using in-silico modelling of coronary flow and particle image velocimetry (PIV). Methods A proximal left anterior descending (pLAD) coronary phantom model was constructed from a patient who had received same day cardiac computed tomography angiography (CTCA) and invasive coronary haemodynamic (Combowire XT) assessment. Patient-specific coronary flow data was applied to CFD boundary conditions and a mock circulatory loop. CFD was validated using PIV under steady flow in a 4-times-scaled model. Same plane velocity field and flow patterns (at mid-luminal of pLAD) from both in-silico and in-vivo data were compared and analysed. Results Mean velocity contours and magnitude were analysed from CFD and PIV. Patient specific average peak velocity obtained from invasive assessment was 0.21m/s. Patient-specific velocity average from CFD was 0.22m/s. The approximated magnitude difference is 4.7%. Both same-axial average cross-sectional velocity estimated by CFD-pLAD and PIV-pLAD are 0.087m/s. Velocity contours and flow patterns simulated in the CFD were also comparable with the PIV results. Conclusion Simulation data from CFD correlate well with experimental PIV results. This early data allows for a non-invasive approach to determine patient-specific coronary haemodynamics (such as velocity profiling and ESS) and form the basis of personalising cardiovascular risk. Insights from this work may aid future development of a novel tool that incorporates CFD-derived ESS estimates with patient-specific risk factors to better predict rapid CAD progression. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Cardiac Society of Australia and New Zealand Monash Institute of Medical Engineering

A segment-to-segment agreement between findings of Cardiac Computed Tomography Angiography and invasive coronary artery angiography

Abstract Introduction Increasing prevalence of ischaemic heart disease (IHD) requires reliable, convenient, and non-invasive screening methods for detection of IHD in early phases. Currently cardiac computed tomography angiography (CCTA) for evaluation for anatomy and in some cases, physiology using non-invasive methods are the method of choice low to moderate IHD patients. Unfortunately, sometimes it seems, that results of CCTA disagree with invasive coronary artery angiography (ICA) results. There was no systemic analysis of segment-to-segment stenosis significance comparison between these two methods (CCTA vs ICA). Therefore, this study aimed to investigate segment-to-segment coronary artery stenosis significance agreement between CCTA, and ICA was performed. Methods In total, 100 patients who underwent CCTA and a diagnostic ICA between June 2021 and December 2021 were prospectively included into this single centre study. For all patients CCTA were performed and for who's with indication for treatment by CCTA, ICA was performed. For all included patients both CCTA and ICA were performed. For coronary artery evaluation 15-segment scheme were chosen in both CCTA and ICA. Coronary arteries were evaluated as follows: right coronary artery (RCA) was divided into 4 segments (S1-S4), left main (S5), left anterior descending (LAD) (S6, S7, S8), first and second diagonals (S9 and S10) and left circumflex (LCx) (S11, S13) and its marginal branches (S12, S14, S15). Segment-to-segment evaluation was performed. The statistical analysis was performed using SPSS 28.0.1.0 statistical analyses package. The chosen level of significance was p&amp;lt;0.05. Results RCA showed following results: S1 (r=−0.02, p=0.87), S2 (r=0.38, p&amp;lt;0.001), S3 (r=0.09, p=0.38) S4 (r=0.30, p=0.002). In LM weak positive correlation was found S5 (r=0.21, p=0.04). In LAD and its diagonal branches following results were found: S6 (r=0.30, p=0.002), S7 (r=0,15, p=0.14), S8 (r=0.28, p=0.004), S9 (r=−0.05, p=0.66), S10 (r=−0.04, p=0.64). Analysis of LCx and its marginal branches revealed S11 (r=0.23, p=0.02), S12 (r=0.22, p=0.03), S13 (r=0.19, p=0.06), S14 (r=0.06, p=0.57), and S15 (r=0.27, p=0.008). Negative non-significant correlations were found in proximal RCA and diagonal branches. That means that in those segments CCTA found more significant lesions, than it was found during ICA. Other segments showed weak positive correlations. The greatest correlations were found in very proximal parts of LAD and LCx. Conclusions The greatest correlations were found in very proximal parts of LAD and LCx in addition to middle RCA segment. Nevertheless, all these correlations were weak. This study failed to show relaible agreement between CCTA and ICA. Funding Acknowledgement Type of funding sources: None.

Hypoattenuated leaflet thickening is associated with silent brain injury

Abstract Background The association between hypoattenuated leaflet thickening (HALT) following transcatheter aortic valve implantation (TAVI) and stroke remains contradictory. Whether HALT carries an increased risk of subclinical brain injury (SBI) has not been investigated. Purpose We investigated whether HALT is associated with SBI on MRI. Furthermore, we assessed whether post-TAVR SBI impacts the patients' cognition and outcome. Methods 153 patients undergoing TAVR were prospectively enrolled. Brain MRI was performed shortly post-TAVR and 6 months (6M) later to assess the occurrence of acute silent cerebral ischaemic lesions (SCIL) and chronic white matter hyperintensities (WMH). HALT was screened by cardiac CT angiography 6M post-TAVR. Neurocognitive evaluation was performed before, shortly after and 6M following TAVR. Results At 6M, 115 patients had diagnostic CTA and 10 had HALT. HALT status, baseline and follow-up MRIs were available in 91 cases. At 6M, new SCIL was evident in 16%, new WMH in 66%. New WMH was more frequent (100% vs 62%; p=0.047) with higher median volume (319 vs 50 mm3; p=0.039) among HALT-patients. In uni- and multivariate analysis, HALT was associated with new WMH volume (beta: 0.72; 95% CI: 0.2–1.39; p=0.009). The patients' cognitive trajectory from pre-TAVR to 6M showed significant association with the 6M SCIL volume (beta: −4.69; 95% CI: −9.13 to −027; p=0.038), but was not related to the presence or volume of new WMH. During a 3.1-year follow-up neither HALT, nor the related WMH burden was related with increased mortality (HALT HR: 0.86, 95% CI: 0,202–3,687; p=0.84; new WMH HR: 1.09; 95% CI: 0,701–1,680; p=0.71). Conclusions 6M post-TAVR, HALT was linked with greater WMH burden, but did not carry an increased risk of cognitive decline or mortality over a 3.1-year follow-up. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): János Bolyai Scholarship of the Hungarian Academy of Sciences

The role of epicardial and pericoronary adipose tissue in cardiometabolic disease

Epicardial adipose tissue (EAT) is a metabolically active fat depot which modulates coronary arterial function. The measurement of EAT volume and attenuation from non-contrast cardiac computed tomography (CT) provides valuable information on cardiometabolic risk. Pericoronary adipose tissue (PCAT), a subset of EAT which directly surrounds the coronary vessels, may function as a sensor of coronary inflammation. PCAT attenuation on coronary CT angiography associates with coronary plaque morphology, stages of coronary artery disease, and risk of future cardiac events. Quantification of EAT and PCAT has incremental and complementary prognostic value over and above current risk assessment tools. This review covers the biological role of EAT in healthy and dysfunctional states, and CT-based assessment of EAT and PCAT towards the development of clinically meaningful imaging biomarkers.

Multimodality imaging in acute myocarditis.

The diagnosis of acute myocarditis often involves several noninvasive techniques that can provide information regarding volumes, ejection fraction, and tissue characterization. In particular, echocardiography is extremely helpful for the evaluation of biventricular volumes, strain and ejection fraction. Cardiac magnetic resonance, beyond biventricular volumes, strain, and ejection fraction allows to characterize myocardial tissue providing information regarding edema, hyperemia, and fibrosis. Contemporary cardiac computed tomography angiography (CCTA) can not only be extremely important for the assessment of coronary arteries, pulmonary arteries and aorta but also tissue characterization using CCTA can be an additional tool that can explain chest pain with a diagnosis of myocarditis.

Subclinical leaflet thrombosis after transcatheter aortic valve implantation is associated with silent brain injury on brain magnetic resonance imaging.

Whether hypoattenuated leaflet thickening (HALT) following transcatheter aortic valve implantation (TAVI) carries a risk of subclinical brain injury (SBI) is unknown. We investigated whether HALT is associated with SBI detected on magnetic resonance imaging (MRI), and whether post-TAVI SBI impacts the patients' cognition and outcome. We prospectively enrolled 153 patients (age: 78.1 ± 6.3 years; female 44%) who underwent TAVI. Brain MRI was performed shortly post-TAVI and 6 months later to assess the occurrence of acute silent cerebral ischaemic lesions (SCIL) and chronic white matter hyperintensities (WMH). HALT was screened by cardiac computed tomography (CT) angiography (CTA) 6 months post-TAVI. Neurocognitive evaluation was performed before, shortly after and 6 months following TAVI. At 6 months, 115 patients had diagnostic CTA and 10 had HALT. HALT status, baseline, and follow-up MRIs were available in 91 cases. At 6 months, new SCIL was evident in 16%, new WMH in 66%. New WMH was more frequent (100 vs. 62%; P = 0.047) with higher median volume (319 vs. 50 mm3; P = 0.039) among HALT-patients. In uni- and multivariate analysis, HALT was associated with new WMH volume (beta: 0.72; 95%CI: 0.2-1.39; P = 0.009). The patients' cognitive trajectory from pre-TAVI to 6 months showed significant association with the 6-month SCIL volume (beta: -4.69; 95%CI: -9.13 to 0.27; P = 0.038), but was not related to the presence or volume of new WMH. During a 3.1-year follow-up, neither HALT [hazard ratio (HR): 0.86; 95%CI: 0.202-3.687; P = 0.84], nor the related WMH burden (HR: 1.09; 95%CI: 0.701-1.680; P = 0.71) was related with increased mortality. At 6 months post-TAVI, HALT was linked with greater WMH burden, but did not carry an increased risk of cognitive decline or mortality over a 3.1-year follow-up (NCT02826200).

Multimodality Imaging of Sudden Cardiac Death and Acute Complications in Acute Coronary Syndrome.

Sudden cardiac death (SCD) is a potentially fatal event usually caused by a cardiac arrhythmia, which is often the result of coronary artery disease (CAD). Up to 80% of patients suffering from SCD have concomitant CAD. Arrhythmic complications may occur in patients with acute coronary syndrome (ACS) before admission, during revascularization procedures, and in hospital intensive care monitoring. In addition, about 20% of patients who survive cardiac arrest develop a transmural myocardial infarction (MI). Prevention of ACS can be evaluated in selected patients using cardiac computed tomography angiography (CCTA), while diagnosis can be depicted using electrocardiography (ECG), and complications can be evaluated with cardiac magnetic resonance (CMR) and echocardiography. CCTA can evaluate plaque, burden of disease, stenosis, and adverse plaque characteristics, in patients with chest pain. ECG and echocardiography are the first-line tests for ACS and are affordable and useful for diagnosis. CMR can evaluate function and the presence of complications after ACS, such as development of ventricular thrombus and presence of myocardial tissue characterization abnormalities that can be the substrate of ventricular arrhythmias.

Usefulness of a novel sizing chart for left atrial appendage occlusion with the Amplatzer Amulet.

The present article aims to compare a novel sizing chart based on both maximum and minimum diameters (novel MATRIX) with the current sizing recommendationinstructions for use(IFU) based on the maximum diameter. Current IFUwith the Amulet device are still based on the maximum left atrial appendage (LAA) diameter, which might lead to inappropriate oversizing, especially in elliptic appendages. This was a retrospective analysis of patients undergoing LAA occlusion in two high-volume centers. Two hundred patients were included (100 patients with baseline cardiac computed tomography angiography[CCTA] and 100 with baseline 2D and 3D-transesophageal echocardiography[TEE]). The degree of concordance between the predicted device size recommendation and the actual device selection was the primary outcome. The novel MATRIX showed a higher level of concordance between the predicted and implanted device size, regardless of imaging modalities. CCTA showed the strongest, and 2D-TEE the weakest concordance between the predicted and implanted device for both MATRIX and IFU charts. The percentage of patients in whom the disagreement among the predicted and implanted device represented &gt;1 size was higher when using the IFU chart. In elliptical LAA anatomies, the differences favoring the use of MATRIX compared to the IFU in terms of predicted/implanted agreement were higher. Finally, no significant differences in clinical or imaging endpoints were observed between the two different sizing charts. Incorporating both the LAA maximum and minimum diameters, as opposed to just maximum diameter, appears to improve sizing accuracy. The proposed MATRIX sizing chart offered a higher level of concordance between predicted and implanted device compared to the current IFU.

Relationship between Coronary Arterial Geometry and the Presence and Extend of Atherosclerotic Plaque Burden: A Review Discussing Methodology and Findings in the Era of Cardiac Computed Tomography Angiography.

Coronary artery disease (CAD) represents a modern pandemic associated with significant morbidity and mortality. The multi-faceted pathogenesis of this entity has long been investigated, highlighting the contribution of systemic factors such as hyperlipidemia and hypertension. Nevertheless, recent research has drawn attention to the importance of geometrical features of coronary vasculature on the complexity and vulnerability of coronary atherosclerosis. Various parameters have been investigated so far, including vessel-length, coronary artery volume index, cross-sectional area, curvature, and tortuosity, using primarily invasive coronary angiography (ICA) and recently non-invasive cardiac computed tomography angiography (CCTA). It is clear that there is correlation between geometrical parameters and both the haemodynamic alterations augmenting the atherosclerosis-prone environment and the extent of plaque burden. The purpose of this review is to discuss the currently available literature regarding this issue and propose a potential non-invasive imaging biomarker, the geometric risk score, which could be of importance to allow the early detection of individuals at increased risk of developing CAD.

A Case for Academic Teleradiology.

A Case for Academic Teleradiology.

Diagnosis and demonstration of single coronary artery by multidetector CT angiography: series of two cases

BackgroundSingle coronary artery (SCA) is a rare anomaly, usually diagnosed incidentally during coronary artery angiogram. Individuals with this anomaly mostly remain asymptomatic while some present with symptoms such as chest pain, dyspnoea and even sudden death. The origin and the proximal course of anomalous coronary artery are the main prognostic factors. Several classification systems have been proposed based on the site of origin and anatomical distribution of anomalous artery. Coronary computed tomography angiography has become the reference method for such an assessment noninvasively. Herein, we report a series of two cases of SCA diagnosed on CT angiography. In one case it was single left coronary artery associated with other congenital cardiac anomalies, whereas in other it was single right coronary artery and was an isolated anomaly.Case presentationOur first case was of a 19-year-old female who presented with chest pain and dyspnoea. Transthoracic Echocardiography (TTE) features were suggestive of Tetralogy of Fallot (TOF) with infective endocarditis. Cardiac CT angiography revealed the presence of a large SCA arising from left aortic sinus with absence of normal origin of right coronary artery (RCA). This artery was dividing into and supplying different coronary arterial territories with pre-pulmonic course of RCA. The patient underwent Aortic valve replacement with pulmonary Commissurotomy and improved in post-operative period. Our second case was of a 50-year-old man with complaints of breathlessness and normal ECG and Echocardiography examination findings. Coronary CT angiography revealed the presence of SCA arising from right aortic sinus and supplying the territories of both RCA and Left coronary artery (LCA). The patient was managed conservatively with emphasis on aggressive control of risk factors.ConclusionsSCA is a rare anomaly and may lead to catastrophic life threatening complications. The accurate delineation of the origin and course of the anomalous vessel is of paramount importance while planning surgical intervention. Management usually involves a multi-disciplinary approach with cardiologists and cardiac surgeons aiming for deciding an individual plan based on presentation and anatomy of each case.

Coronary CT Value in Quantitative Assessment of Intermediate Stenosis.

Background and Objectives: Cardiac computed tomography angiography (CCTA) is an excellent non-invasive imaging tool to evaluate coronary arteries and exclude coronary artery disease (CAD). Managing intermediate coronary artery stenosis with negative or inconclusive functional tests is still a challenge. A regular stenosis evaluation together with high-risk plaque features, using semi-automated programs, are becoming promising tools. This case–control study was designed to evaluate the intermediate lesion features’ impact on CAD outcomes, using a semi-automated CCTA atherosclerotic plaque analysis program. Materials and Methods: We performed a single-center, prospective cohort study. A total of 133 patients with low to intermediate risk of CAD, older than 18 years with no previous history of CAD and good quality CCTA images were included in the study, and 194 intermediate stenosis (CAD-RADS 3) were analyzed. For more detailed morphological analysis, we used semi-automated CCTA-dedicated software. Enrolled patients were prospectively followed-up for 2 years. Results: Agatston score was significantly higher in the major adverse cardiovascular events (MACE) group (p = 0.025). Obstruction site analysis showed a significantly lower coronary artery remodeling index (RI) among patients with MACE (p = 0.037); nonetheless RI was negative in both groups. Plaque consistency analysis showed significantly bigger necrotic core area in the MACE group (p = 0.049). In addition, unadjusted multivariate analysis confirmed Agatston score and RI as significant MACE predictors. Conclusions: The Agatston score showes the total area of calcium deposits and higher values are linked to MACE. Higher plaque content of necrotic component is also associated with MACE. Additionally, negatively remodeled plaques are linked to MACE and could be a sign of advanced CAD. The Agatston score and RI are significant in risk stratification for the development of MACE.

Assessment of Device Neoendothelialization With Cardiac Computed Tomography Angiography After Transcatheter Closure of Atrial Septal Defect.

Background:Although the transcatheter closure of atrial septal defect was established as the treatment of choice several decades ago, the process of device neoendothelialization (NE) in humans is not well understood. We aimed to measure the extent of device NE using cardiac computed tomography angiography and analyze its risk factors.Methods:Between January 2005 and February 2021, we retrospectively reviewed 164 devices of 112 patients on cardiac computed tomography angiography. We investigated device shape, contrast opacification within the device that differentiated device NE, and device-related thrombosis or vegetation. Risk factor analysis for major adverse cardiovascular events and incomplete NE according to the postprocedural period was performed.Results:Seventy patients (62.5%) were women, with a median (range) age at the time of device closure of 44.5 (0.6–79.2) years. The mean (±SD) defect size was 16.6 (±7.8) mm, and patients were followed for 35.9±33.9 months. After 6 months of device implantation, 35% of the devices (42/120) had incomplete NE. The intensity of intradevice opacification shifted from complete to partial or nonopacification over time (P<0.001), and a similar pattern was observed in the shunt flow (P<0.001). The bulkiness of devices also decreased in proportion to the postprocedural period (P<0.001). Risk analysis revealed device diameter (hazard ratio, 1.18 [95% CI, 1.04–1.27]; P<0.001) as the only significant factor of incomplete NE and major adverse events.Conclusions:Incomplete NE of atrial septal defect devices was identified on cardiac computed tomography angiography in significant numbers after 6 months of the procedure. The device diameter was related to incomplete NE and major adverse events. Further prospective and multicenter studies are warranted to validate this new assessment of device NE.

401 Deepheartct: A Fully Automatic Hybrid Structure Segmentation Framework Based On Atlas, Reverse Ranking, And Convolutional Neural Network For Computed Tomography Angiography

Introduction: Cardiac computed tomography angiography (CTA) opens new opportunities on image analysis for diagnosing cardiovascular disease. Manual delineation remains the main method to quantify different chambers on CTA images. Deep learning (DL) methods have shown great promise in medical image analysis. However, DL requires large and high-quality training labels which are often limited due to its labor intensive nature. We aim to develop a fully automatic artificial intelligence system based on an optimal computer-labeled dataset for accurate CTA segmentation.

415 Canary In A Coal Mine In NSTEMI? AI-QCT Evaluation Of Atherosclerosis And 2-year Outcomes After CCTA

Introduction: Intermediate-term outcomes of cardiac computed tomography angiography (CCTA) in low to intermediate risk acute coronary syndromes (ACS) is uncertain. There is scarce data on associated plaque findings of atherosclerosis imaging-quantitative computed tomography (AI-QCT) guided by artificial intelligence in these patients

402 Artificial Intelligence Based CT Quantification Of Left Ventricular Mass

Introduction: Left ventricular (LV) mass is a well-established predictor of major adverse cardiovascular events. Cardiac magnetic resonance is the gold-standard for LV mass measurement, however cardiac computed tomography angiography (CCTA) is an equally accepted modality and has been shown to have prognostic value. In this study, we aimed to develop, validate, and test a fully automated artificial intelligence based system capable of quantifying LV mass on CCTA.

460 Comparison Between Cardiac Magnetic Resonance Imaging And Cardiac Computed Tomography For Quantification Of Myocardial Extracellular Volume Fraction: A Meta-analysis

Introduction: Extracellular volume (ECV) is a quantitative measure of extracellular compartment expansion, and an increase in ECV is a marker of myocardial fibrosis. While cardiac magnetic resonance (CMR) is considered the standard imaging tool for ECV quantification, cardiac CT angiography (CTA) has also been used for ECV quantification. The aim of this meta-analysis is to evaluate the correlation and agreement in the quantification of myocardial ECV by CTA and CMR.