SCCT 2021 Expert Consensus Document on Coronary Computed Tomographic Angiography: A Report of the Society of Cardiovascular Computed Tomography

Artificial intelligence driven plaque characterization and functional assessment from CCTA using OCT-based automation: A prospective study

BACKGROUND

We aimed to develop and validate an Artificial Intelligence (AI) model that leverages CCTA and optical coherence tomography (OCT) images for automated analysis of plaque characteristics and coronary function.

METHODS

A total of 100 patients who underwent invasive coronary angiography, OCT, and CCTA before discharge were included in this study. The data were randomly divided into a training set (80 %) and a test set (20 %). The training set, comprising 21,471 tomography images, was used to train a deep-learning convolutional neural network. Subsequently, the AI model was integrated with flow reserve score calculation software developed by Ruixin Medical.

RESULTS

The results from the test set demonstrated excellent agreement between the AI model and OCT analysis for calcified plaque (McNemar test, p = 0.683), non-calcified plaque (McNemar test, p = 0.752), mixed plaque (McNemar test, p = 1.000), and low-attenuation plaque (McNemar test, p = 1.000). Additionally, there was excellent agreement for deep learning-derived minimum lumen diameter (intraclass correlation coefficient [ICC] 0.91, p < 0.001), mean vessel diameter (ICC 0.88, p < 0.001), and percent diameter stenosis (ICC 0.82, p < 0.001). In diagnosing >50 % coronary stenosis, the diagnostic accuracy of the AI model surpassed that of conventional CCTA (AUC 0.98 vs. 0.76, p = 0.008). When compared with quantitative flow fraction, there was excellent agreement between QFR and AI-derived CT-FFR (ICC 0.745, p < 0.0001).

CONCLUSION

Our AI model effectively provides automated analysis of plaque characteristics from CCTA images, with the analysis results showing strong agreement with OCT findings. Moreover, the CT-FFR automatically analyzed by the AI model exhibits high consistency with QFR derived from coronary angiography.

3D non-contrast whole‑heart coronary MR angiography at 3 T with compressed sensing in elderly patients: Optimization of the acceleration factor

Background

Coronary magnetic resonance angiography (CMRA) is increasingly used in clinical practice, but lengthy scan times can be challenging for elderly patients. This study evaluates the impact of compressed sensing (CS) technology on image quality and diagnostic performance of 3 T CMRA in elderly patients, aiming to identify the optimal acceleration factor.

Methods

We prospectively enrolled elderly individuals who underwent coronary computed tomography angiography (CCTA) from June to November 2023 for non-contrast whole-heart CMRA with CS acceleration factors of 4, 6, or 8. Elderly volunteers rated their experiences with the optimal acceleration factor. Image quality and diagnostic performance were analyzed using a general linear model and the area under the receiver operating characteristic curves (AUC), with CCTA as the reference standard.

Results

Sixty-seven individuals (34 men, mean age 74.3 ± 7.2 years) were enrolled. Scan times significantly decreased from 578.6 ± 131.4 s to 366.1 ± 91.2 s and 261.1 ± 76.5 s for acceleration factors 4, 6, and 8, respectively. Subjective image quality scores, signal-to-noise ratio, and contrast-to-noise ratio were significantly better with CS4 and CS6 than with CS8. Diagnostic performance declined with increasing acceleration, with sensitivities of 92.2 %, 88.0 %, and 72.5 %, and specificities of 94.1 %, 92.6 %, and 85.3 % for CS4, CS6, and CS8, respectively. CS6 was determined to be the optimal acceleration factor. Volunteers reported that CS6 was more acceptable than CS4.

Conclusions

CMRA with CS6 provides rapid scanning while maintaining adequate diagnostic performance, making it a reliable alternative to CCTA for diagnosing coronary artery disease in elderly patients.

Assessment of inter- and intrareader agreement among different stenosis quantification methods in coronary CT angiography

PURPOSE

To assess the inter- and intrareader agreement among different subjective and objective measurement methods to grade coronary artery stenosis in coronary CT angiography (CCTA).

METHODS

In this retrospective study, consecutive patients of a one-year cohort who received a clinically indicated CCTA in 2023 and had a CAD-RADS2.0 score of 3 or 4 were included. Five different radiologists (three subspecialized in cardiac imaging) independently graded the most severe coronary artery stenosis using different measurement methods: visual stenosis grading and objective stenosis grading measuring stenosis diameter and area. Interreader agreement of percentage stenosis were calculated for each measurement method and stratified by the coronary calcium score (CACS) using Krippendorf α. Intrareader assessment was performed for one subspecialized radiologist.

RESULTS

A total of 61 patients were included (mean age, 65 ± 10 years; 18 women). Interreader agreements for percentage stenoses as determined visually and as measured by diameter and area were moderate independent of measurement method (0.42, 0.46, 0.41 for visual, diameter and area percentage stenoses, respectively) and did not depend on subspecialization. Intrareader agreement was moderate to substantial with values of 0.67, 0.57 and 0.53 for visual, diameter and area percentage stenoses. There was a trend towards lower inter- and intrareader agreement for stenoses with high CACS (e.g. for visual grading: 0.44 vs. 0.2 for interreader agreement between non-calcified stenoses (CACS = 0) and calcified stenoses (CACS ≥ 100)).

CONCLUSION

Inter- and intrareader agreement for stenosis quantification in coronary CT angiography was overall moderate and did not differ significantly among visual and objective measurement methods. A trend towards lower agreement was observed for stenoses with higher CACS.

Myocardial extracellular volume fraction with spectral detector computed tomography for risk stratification in non-ischemic heart failure

PURPOSE

To validate the feasibility of using late iodine enhancement (LIE)-derived ECV on iodine density images using spectral detector computed tomography (SDCT; CT-ECV) and to assess the potential of CT-ECV for risk stratification among patients with non-ischemic heart failure (NIHF).

MATERIALS AND METHODS

Forty-five subjects who underwent cardiac SDCT and CMR were included in the validation group to calculate and compare CT-ECV with CMR-ECV to validate CT-ECV feasibility. Another 117 subjects (82 patients with NIHF, 35 controls) who underwent SDCT were included in the experimental group to explore the potential of CT-ECV for risk stratification. ECV was measured via iodine density images and CMR T1 mapping in accordance with American Heart Association 16-segment models.

RESULTS

In the validation group, there was no significant difference between CT-ECV and CMR-ECV (P = 0.293), with an insignificant bias. In the experimental group, CT-ECV in patients with NIHF was significantly higher than in controls (P < 0.05). In 82 patients with NIHF, CT-ECV in HFrEF ( HF with reduced ejection fraction: LVEF ≤ 40%) patients was statistically higher than that of HFmEF (HF with mildly reduced ejection fraction: LVEF 41-49%) and HFpEF (HF with preserved ejection fraction: LVEF ≥ 50%) patients (P < 0.05) and a significant difference among patients with NIHF with varied New York Heart Association classes (all P < 0.05); In addition, Kaplan-Meier survival curves and Log-rank test demonstrated that NIHF patients with CT-ECV ≥ 31.29% had higher probability of MACE than NIHF patients with CT-ECV < 31.29% (P < 0.001).

CONCLUSION

LIE-derived CT-ECV on iodine density images using SDCT is a promising practical alternative to CMR-ECV, with the potential to assist with risk stratification among patients with NIHF.

Rationale and design of the CT-STEMI study (Cardiac Computed Tomography for comprehensive risk stratification of arrhythmic, atherothrombotic and heart failure events following reperfused ST-segment Elevation Myocardial Infarction)

BACKGROUND

ST-segment elevation myocardial infarction (STEMI) remains a major cause of morbidity and mortality, with survivors facing high risk of heart failure, recurrent ischemia, and arrhythmias. Risk stratification traditionally relies on echocardiography, while cardiac magnetic resonance (CMR) is the most effective tool for predicting adverse outcomes. However, its routine use is limited by accessibility, cost, and logistical constraints. Recently, cardiac computed tomography (CCT) has evolved from an angiographic tool to a comprehensive imaging modality capable of assessing wall motion abnormalities and myocadial tissue characteristics.

OBJECTIVES

The CT-STEMI study aims to (1) evaluate the diagnostic accuracy of CCT for myocardial morphofunctional assessment and tissue characterization compared to CMR, (2) determine the prognostic value of CCT-derived features for adverse outcomes, and (3) assess the role of CCT in quantifying atherosclerotic burden in STEMI patients.

METHODS

CT-STEMI (NCT06020209) is a prospective, multicenter observational study enrolling STEMI patients treated with primary PCI within 24 ​h of symptom onset. Each patient undergoes comprehensive CCT (pre-contrast imaging, full R-R interval angiography, and late iodine enhancement) and CMR within 10 days of the acute event, with imaging sequence randomized. Patients will be followed longitudinally for heart failure, arrhythmic events, and recurrent ischemic complications.

SUMMARY

This study aims to validate CCT as a cost-effective, comprehensive imaging modality for post-STEMI risk stratification, with the added benefit of coronary artery evaluation. If successful, CCT could serve as an efficient, one-stop diagnostic tool, enhancing patient outcomes while optimizing healthcare resources.

Optimizing Coronary CT Image Reconstruction With Deep Learning for Improved Quality: A Retrospective Study

OBJECTIVE

To evaluate the impact of deep learning image reconstruction on image quality in CCTA compared with adaptive statistical iterative reconstruction (ASIR).

MATERIALS AND METHODS

CCTA data sets from 100 consecutive patients with suspected CAD were acquired with a Revolution Apex 256-row CT scanner, reconstructed with ASIR-V and DLIR-H, and subsequently analyzed. Image noise, SNR, and CNR in five regions of interest (25 mm) were calculated and t tested. The normality of quantitative variables was assessed using the Shapiro-Wilk test. For non-normally distributed data, the Mann-Whitney U test was applied. The concordance of HU values within specific ROIs was analyzed with Bland-Altman plots. Correlation between ASIR-V and DLIR-H was conducted using the Spearman rank correlation test.Subjective image analysis was conducted using a 5-point scale to evaluate noise level, vascular enhancement smoothness, artifact reduction, and diagnostic confidence. Intraclass correlation (ICC) was used to assess the reliability and consistency of subjective ratings among the reader.

RESULTS

DLIR-H significantly reduced image noise across all ROIs (from 15% to 41%, all P<0.05), compared with ASIR-V. Mean SNR (ASIR-V vs. DLIR-H) were septum=4.3±1.7 versus 6.4±2.2; cavity of the left ventricle=24.3±8.3 versus 36.6±11.7; CNR: septum=8.2±2.5 versus 12.4±3.5; cavity of left ventricle= 28.2±9.1 versus 42.5±13.0. Spearman rank correlation ranged from 0.64 to 0.79 (P<0.05). Bland-Altman analysis showed good agreement between ASIR-V and DLIR-H, with no discernible patterns. Subjectively, DLIR-H significantly outperformed ASIR-V across all evaluated criteria (all P<0.05). ICC values indicated strong agreement among readers, demonstrating excellent reliability for most criteria and good reliability for vascular enhancement smoothness.

CONCLUSIONS

DLIR-H significantly improved CCTA image quality compared with ASIR-V, which contributes to a more accurate diagnosis in patients with suspected CAD.

Deep learning reconstruction algorithm and high-concentration contrast medium: feasibility of a double-low protocol in coronary computed tomography angiography

OBJECTIVE

To evaluate radiation dose and image quality of a double-low CCTA protocol reconstructed utilizing high-strength deep learning image reconstructions (DLIR-H) compared to standard adaptive statistical iterative reconstruction (ASiR-V) protocol in non-obese patients.

MATERIALS AND METHODS

From June to October 2022, consecutive patients, undergoing clinically indicated CCTA, with BMI < 30 kg/m2 were prospectively included and randomly assigned into three groups: group A (100 kVp, ASiR-V 50%, iodine delivery rate [IDR] = 1.8 g/s), group B (80 kVp, DLIR-H, IDR = 1.4 g/s), and group C (80 kVp, DLIR-H, IDR = 1.2 g/s). High-concentration contrast medium was administered. Image quality analysis was evaluated by two radiologists. Radiation and contrast dose, and objective and subjective image quality were compared across the three groups.

RESULTS

The final population consisted of 255 patients (64 ± 10 years, 161 men), 85 per group. Group B yielded 42% radiation dose reduction (2.36 ± 0.9 mSv) compared to group A (4.07 ± 1.2 mSv; p < 0.001) and achieved a higher signal-to-noise ratio (30.5 ± 11.5), contrast-to-noise-ratio (27.8 ± 11), and subjective image quality (Likert scale score: 4, interquartile range: 3-4) compared to group A and group C (all p ≤ 0.001). Contrast medium dose in group C (44.8 ± 4.4 mL) was lower than group A (57.7 ± 6.2 mL) and B (50.4 ± 4.3 mL), all the comparisons were statistically different (all p < 0.001).

CONCLUSION

DLIR-H combined with 80-kVp CCTA with an IDR 1.4 significantly reduces radiation and contrast medium exposure while improving image quality compared to conventional 100-kVp with 1.8 IDR protocol in non-obese patients.

CLINICAL RELEVANCE STATEMENT

Low radiation and low contrast medium dose coronary CT angiography protocol is feasible with high-strength deep learning reconstruction and high-concentration contrast medium without compromising image quality.

KEY POINTS

Minimizing the radiation and contrast medium dose while maintaining CT image quality is highly desirable. High-strength deep learning iterative reconstruction protocol yielded 42% radiation dose reduction compared to conventional protocol. "Double-low" coronary CTA is feasible with high-strength deep learning reconstruction without compromising image quality in non-obese patients.

Selecting the optimal candidates for percutaneous mitral valvuloplasty using multi-modality imaging

AIMS

This study compared echocardiography (echo) and cardiac computed tomography (CT) in measuring the Wilkins score and evaluated the potential added benefit of CT in predicting immediate percutaneous mitral valvuloplasty (PMV) outcomes in rheumatic mitral stenosis (MS) patients deemed eligible for PMV by echo.

METHODS AND RESULTS

From a multicentre registry of 3,140 patients with at least moderate MS, we included 96 patients (age 56.4 ± 11.5 years, 81% female) eligible for PMV based on echo Wilkins score (≤9) who underwent PMV and had measurable CT and echo images. We compared Wilkins scores from both modalities and analysed their relationship with unsuccessful procedural outcomes, defined as sub-optimal post-procedural mitral valve area (<1.5 cm2) or newly developed mitral regurgitation Grade ≥III. The mean CT score was higher than the echo score (8.0 ± 2.4 vs. 7.3 ± 1.2 points, P = 0.005). Procedural success was achieved in 65 (67.7%) patients. Unsuccessful results occurred in 31 patients, primarily in intermediate echo score (7-9 points) group. Among patients with intermediate echo scores, 90% had high CT scores (≥9), which were associated with significantly higher rates of unsuccessful PMV compared with lower CT scores (61.1 vs. 18.9%, P < 0.001).

CONCLUSION

CT-derived Wilkins scores were higher than echo-derived scores, with the most significant discrepancy in the intermediate echo score group. CT identified a subgroup of patients at higher risk for unsuccessful PMV among those with intermediate echo-based feasibility. Patients with intermediate echo-based PMV feasibility may benefit from CT-based reclassification, potentially improving patient selection and procedural outcomes.

Influence of plaque characteristics by coronary computed tomography angiography on lesion-specific ischemia: a systematic review and meta-analysis

OBJECTIVES

To evaluate the association between plaque characteristics and burden by coronary computed tomography angiography (CCTA) and ischemia determined by invasively measured fractional flow reserve (FFR), and whether the addition of plaque characteristics improves ischemia discrimination beyond coronary stenosis alone.

METHODS

A systematic literature review and meta-analysis of studies from PubMed, EMBASE, and the Cochrane Library databases, published between January 2005 and October 2024 were conducted to assess the relationship between quantitative and qualitative coronary plaque characteristics and invasive FFR. Pooled analyses were performed using weighted mean difference for plaque volumes with 95% confidence intervals and odds ratios for qualitative plaque findings.

RESULTS

A total of 29 studies involving 4416 patients (mean age 63 ± 9 years and 71% male) with predominantly stable coronary artery disease were included. Data on 3923 lesions and 3520 vessels were pooled. Total plaque, non-calcified plaque, and percent aggregate plaque volumes, as well as percent plaque burden, were inversely associated with FFR at both per-lesion and per-vessel levels (all, p-values < 0.05). The presence of high-risk plaque characteristics, including low-attenuation plaque, napkin-ring sign, and spotty calcification, were more frequently observed in lesions and vessels with FFR ≤ 0.80 (all, p-values < 0.05). Among plaque volumes, the percent aggregate plaque volume consistently improved ischemia discrimination independently of stenosis.

CONCLUSION

CCTA-derived quantification of plaque volumes and identification of high-risk plaque characteristics are associated with ischemia and significantly enhance discrimination of ischemia-causing lesions independently of coronary stenosis severity.

KEY POINTS

Question Plaque characteristics have been suggested as the missing link between coronary artery stenosis severity and ischemia. Findings High-risk plaque characteristics and larger coronary plaque volumes are associated with ischemia (FFR ≤ 0.80). Clinical relevance The addition of CCTA-derived plaque assessment improved the discrimination of ischemia compared with stenosis evaluation alone. Combining coronary stenosis and plaque assessment may improve the non-invasive assessment of patients with coronary artery disease and gatekeeping to the catheterization laboratory.

Predictors of Diagnostic Inaccuracy of Detecting Coronary Artery Stenosis by Preprocedural CT Angiography in Patients Prior to Transcatheter Aortic Valve Implantation

Background: The diagnostic performance of preprocedural CT angiography in detecting coronary artery disease (CAD) in patients scheduled for transcatheter aortic valve implantation (TAVI) has been reported. However, data on predictors of diagnostic inaccuracy are sparse. We sought to investigate clinical characteristics and imaging criteria that predict the inaccurate assessment of coronary artery stenosis based on pre-TAVI-CT. Methods: The patient- and vessel-level analysis of all CT datasets from 192 patients (mean age 82.1 ± 4.8 years; 63.5% female) without known CAD or severe renal dysfunction was performed retrospectively in a blinded fashion. Significant CAD was defined as a CAD-RADS™ 2.0 category ≥ 4 by CT. Invasive coronary angiography (ICA) served as the reference standard for relevant CAD (≥70% luminal diameter stenosis or fractional flow reserve ≤ 0.80). Pertinent clinical characteristics and imaging criteria of all true-positive (n = 71), false-positive (n = 30), false-negative (n = 4), and true-negative patient-level CT diagnoses (n = 87) for relevant stenosis according to ICA were assessed. Results: In the univariate per-patient analysis, the following parameters yielded discriminative power (p < 0.10) regarding inaccurate CAD assessment by pre-TAVI-CT: age, atrial fibrillation, scanner generation, and image quality. Factors independently associated with CT diagnostic inaccuracy were determined using multivariable logistic regression analysis: a younger age (odds ratio [OR] 0.87; 95% confidence interval [CI] 0.80 to 0.94; p < 0.01) and insufficient CT image quality (OR 0.6; CI 0.41 to 0.89; p < 0.01). Conclusions: Our results demonstrate younger age and poor CT image quality to predict less accurate CAD assessments by pre-TAVI-CT in comparison with ICA. Knowledge of these predictors may aid in more efficient coronary artery interpretations based on pre-TAVI-CT.

Successful pharmaco-mechanical treatment of a subtotally occluded venous bypass graft in a patient presenting with acute coronary syndrome: a case report and review of the current literature on the role of local thrombolysis

Coronary artery bypass grafting (CABG) is a common and effective treatment for patients with complex coronary artery disease. This case report discusses a 75-year-old male patient who presented with angina and shortness of breath due to thrombus formation in a venous graft 20 years after CABG. Initial diagnostics indicated non-ST-elevation myocardial infarction, leading to immediate intervention. Cardiac catheterization revealed thrombus in the vein graft to the large first diagonal branch, necessitating percutaneous coronary intervention. Despite initial efforts, thrombus aspiration and further catheter advancement were unsuccessful. A combination of balloon angioplasty, stent implantation, and intra-arterial thrombolysis with recombinant tissue plasminogen activator (rt-PA) was employed, resulting in significant thrombus reduction and improved coronary flow. Follow-up coronary CT angiography (CCTA) confirmed complete thrombus resolution and patent graft. The patient was discharged with dual antiplatelet therapy and showed favorable outcomes. This case emphasizes the challenges of managing thrombotic complications in venous bypass grafts and highlights the effectiveness of a multifaceted interventional approach combined with CCTA for non-invasive patient follow-up and assessment of treatment success. Furthermore, a review of the current literature on the role of local thrombolysis for occluded coronary artery bypass grafts is provided.

Early Structural Cardiovascular Disease, HIV, and Tuberculosis in East Africa (ASANTE): Cross-sectional study protocol for a multimodal cardiac imaging study in Nairobi, Kenya

Introduction

Persons living with HIV (PLWH) have an augmented risk of cardiovascular disease, including atherosclerosis and myocardial dysfunction, despite effective viral suppression with antiretroviral therapy (ART). Despite the majority of PLWH residing in sub-Saharan Africa, there are limited reports from the region on structural cardiovascular changes due to this residual risk.

Methods and analysis

The Early Structural Cardiovascular Disease, HIV, and Tuberculosis (ASANTE) cross-sectional study will be conducted in a public hospital in Nairobi, Kenya. It will enroll 400 participants (50% female, 50% PLWH) to undergo comprehensive cardiovascular phenotyping using multimodal imaging (coronary CT angiography [CCTA], echocardiography) and banking of biological samples (whole blood, peripheral blood mononuclear cells, serum, and urine). We will define the prevalence of subclinical coronary atherosclerosis by coronary CT angiography (CCTA) and subclinical myocardial dysfunction by transthoracic echocardiography, and evaluate both traditional and non-traditional risk factors, including endemic infections such as latent tuberculosis. This study will contribute important data on phenotypes of and risk factors for HIV-associated cardiovascular disease in this under-studied region.

Ethics and dissemination

Ethical approval for the ASANTE study was granted by the University of Nairobi-Kenyatta National Hospital Ethical Review Committee, Nairobi, Kenya. Results will be submitted for publication in peer-reviewed journals.

Automated proximal coronary artery calcium identification using artificial intelligence: advancing cardiovascular risk assessment

AIMS

Identification of proximal coronary artery calcium (CAC) may improve prediction of major adverse cardiac events (MACE) beyond the CAC score, particularly in patients with low CAC burden. We investigated whether the proximal CAC can be detected on gated cardiac CT and whether it provides prognostic significance with artificial intelligence (AI).

METHODS AND RESULTS

A total of 2016 asymptomatic adults with baseline CAC CT scans from a single site were followed up for MACE for 14 years. An AI algorithm to classify CAC into proximal or not was created using expert annotations of total and proximal CAC and AI-derived cardiac structures. The algorithm was evaluated for prognostic significance on AI-derived CAC segmentation. In 303 subjects with expert annotations, the classification of proximal vs. non-proximal CAC reached an area under receiver operating curve of 0.93 [95% confidence interval (CI) 0.91-0.95]. For prognostic evaluation, in an additional 588 subjects with mild AI-derived CAC scores (CAC score 1-99), the AI proximal involvement was associated with worse MACE-free survival (P = 0.008) and higher risk of MACE when adjusting for CAC score alone [hazard ratio (HR) 2.28, 95% CI 1.16-4.48, P = 0.02] or CAC score and clinical risk factors (HR 2.12, 95% CI 1.03-4.36, P = 0.04).

CONCLUSION

The AI algorithm could identify proximal CAC on CAC CT. The proximal location had modest prognostic significance in subjects with mild CAC scores. The AI identification of proximal CAC can be integrated into automatic CAC scoring and improves the risk prediction of CAC CT.

Real-world application of CCTA with CT-FFR for coronary assessment pre-TAVI: the CT2TAVI study

This study aims to evaluate the implementation of concomitant CAD assessment on pre-TAVI (transcatheter aortic valve implantation) planning CTA (CT angiography) aided by CT-FFR (CT-fractional flow reserve) [The CT2TAVI protocol] and investigates the incremental value of CT-FFR to coronary CT angiography (CCTA) alone in the evaluation of patients undergoing CT2TAVI. This is a prospective observational real-world cohort study at an academic health system on consecutive patients who underwent CTA for TAVI planning from 1/2021 to 6/2022. This represented a transition period in our health system, from not formally reporting CAD on pre-TAVI planning CTA (Group A) to routinely reporting CAD on pre-TAVI CTA (Group B; CT2TAVI protocol). All CTAs were retrospective ECG-gated using a dual source 192 slice CT scanner without nitrate or intravenous beta blocker premedication. We assessed downstream ICA and revascularization pre-TAVI and clinical outcomes 30 days and 1 year post-TAVI in both groups. 307 patients were included with 199 patients in Group A and 108 patients in Group B. In Group B, ICA was performed pre-TAVI in only 40.7% of patients. The use of CT-FFR, which was primarily aimed at identifying hemodynamically significant proximal vessel disease, helped avoid downstream invasive testing for 60.5% (23/38) of patients who were deemed to have obstructive proximal vessel disease using CCTA alone or had one or more uninterpretable proximal segments using CCTA. All-cause mortality, cardiovascular mortality, myocardial infarction and need for revascularization at 1-year post-TAVI were comparable between groups with a higher trend toward heart failure hospitalizations in Group A. Routine ICA can safely be deferred pre-TAVI, with the CT2TAVI strategy using modern CT scanners aided by CT-FFR analysis.

Coronary CTA and CT-FFR in trans-catheter aortic valve implantation candidates: a systematic review and meta-analysis

OBJECTIVES

Screening for obstructive coronary artery disease (CAD) with coronary computed tomography angiography (CCTA) could prevent unnecessary invasive coronary angiography (ICA) procedures during work-up for trans-catheter aortic valve implantation (TAVI). CT-derived fractional flow reserve (CT-FFR) improves CCTA accuracy in chest pain patients. However, its reliability in the TAVI population is unknown. This systematic review and meta-analysis assesses CCTA and CT-FFR in TAVI candidates.

METHODS

PubMed, Embase and Web of Science were searched for studies regarding CCTA and/or CT-FFR in TAVI candidates. Primary endpoint was correct identification and rule-out of obstructive CAD. Results were pooled in a meta-analysis.

RESULTS

Thirty-four articles were part of the meta-analysis, reporting results for CCTA and CT-FFR in 7235 and 1269 patients, respectively. Reference standard was mostly anatomical severity of CAD. At patient level, pooled CCTA sensitivity was 94.0% and specificity 72.4%. CT-FFR sensitivity was 93.2% and specificity 70.3% with substantial variation between studies. However, in studies that compared both, CT-FFR performed better than CCTA. Sensitivity of CCTA versus CT-FFR was 74.9% versus 83.9%, and specificity was 65.5% versus 89.8%.

CONCLUSIONS

Negative CCTA accurately rules out CAD in the TAVI population. CCTA could lead to significant reduction in pre-TAVI ICA, but false positives remain high. Diagnostic accuracy of CT-FFR was comparable to that of CCTA in our meta-analyses, but in studies performing a direct comparison, CT-FFR performed better than CCTA. However, as most studies were small and used CT-FFR software exclusively available for research, a large study on CT-FFR in TAVI work-up using commercially available CT-FFR software would be appropriate before considering routine implementation.

KEY POINTS

Question Coronary artery disease (CAD) screening with invasive coronary angiography before trans-catheter aortic valve implantation (TAVI) is often retrospectively unnecessary, revealing no obstructive CAD. Findings Coronary CTA ruled out CAD in approximately half of TAVI candidates. CT-derived fractional flow reserve (CT-FFR) performed similarly overall but better than coronary CTA in direct comparison. Clinical relevance Addition of coronary CTA to TAVI planning-CT to screen for obstructive CAD could reduce negative invasive coronary angiographies in TAVI work-up. CT-FFR could reduce false-positive coronary CTA results, improving its gatekeeper function in this population, but more data is necessary.

Training and Verification Requirements for Interpretation of Cardiac CT and MRI: AJR Expert Panel Narrative Review

The use of cardiac CT and MRI is rapidly expanding based on strong evidence from large international trials. The number of physicians competent to interpret cardiac CT and MRI may be unable to keep pace with the increasing demand. Societies and organizations have prescribed training requirements for interpreting cardiac CT and MRI, with recent updates focusing on the increased breadth of competency that is now required due to ongoing imaging advances. In this AJR Expert Panel Narrative Review, we discuss several aspects of cardiac CT and MRI training, focusing on topics that are uncertain or not addressed in existing society statements and guidelines, including determination of competency in different practice types in real-world settings and the impact of artificial intelligence on training and education. The article is intended to guide updates in professional society training requirements and also inform institutional verification processes.

Diagnostic performance of CCTA and CTP imaging for clinically suspected in-stent restenosis: A meta-analysis

AIMS

The objective of this study is to conduct a meta-analysis to assess the diagnostic performance of Coronary Computed Tomography Angiography (CCTA) and a hybrid approach that incorporates Computed Tomography Perfusion (CTP) in addition to CCTA (CCTA ​+ ​CTP) for the detection of in-stent restenosis (ISR), as defined by angiography.

METHODS

A comprehensive search of articles identified 18,513 studies. After removing duplicates, title/abstract screening, and full-text review, 17 CCTA and 3 CCTA ​+ ​CTP studies were included. Only studies using ≥64-slices multidetector computed tomography (CT) were considered eligible.

RESULTS

The per-patient ISR prevalence was 43 ​%, with 92 ​% of stents fully interpretable with CCTA. Meta-analysis exhibited a per-stent CCTA (n ​= ​2674) sensitivity of 90 ​% (95 ​% CI; 84-94 ​%), specificity of 89 ​% (95 ​% CI; 86-92 ​%), positive likelihood ratio of 7.17 (95 ​% CI; 5.24-9.61), negative likelihood ratio of 0.17 (95 ​% CI; 0.10-0.25), and diagnostic odds ratio of 45.7 (95 ​% CI; 22.71-82.43). Additional sensitivity analyses revealed no influence of stent diameter or strut thickness on the diagnostic yield of CCTA. The per-stent diagnostic performance of CCTA ​+ ​CTP (n ​= ​752) did not show differences compared to CCTA.

CONCLUSIONS

With currently utilized scanners, CCTA and CCTA ​+ ​CTP demonstrated high diagnostic performance for in-stent restenosis evaluation. Consequently, a history of previous stent implantation should not be an argument to preclude using these methods in clinically suspected patients.

Evaluation of the clinical value of CCTA as the preferred screening method in patients with chronic coronary syndrome

BACKGROUND

The advantages and disadvantages of direct invasive coronary angiography (ICA) and coronary computed tomographic angiography (CCTA) + ICA were compared in patients with suspected chronic coronary syndrome (CCS) who presented with angina symptoms or who had nonangina chest pain with abnormal electrocardiogram results.

METHODS

A total of 1200 patients who met the inclusion criteria at TEDA International Cardiovascular Hospital from January 2021 to December 2022 were randomly divided into two groups at a 1:1 ratio: the CCTA + ICA strategy (CCTA group) and the direct ICA strategy (ICA group). The baseline data were collected. All patients in the CCTA group underwent CCTA examination first. If these results showed positive obstructive coronary artery disease (CAD), then typical angina with coronary artery stenosis ranging from 50 to 70% or vascular segments could not be analysed due to severe calcification, so ICA was further performed for definitive diagnosis, and the ICA results were taken as the final diagnosis. All patients in the ICA group underwent ICA examination directly. Demographic data, cardiovascular risk factors, biochemical criteria, chest pain classification, coronary vessel lesion severity and drug use were compared between the two groups. All patients were followed for 1 year after discharge to observe major adverse cardiovascular events (MACE). The differences in unnecessary ICA rates, 1-year MACE rates, allergic reactions to contrast agents and hospitalization costs between the two groups were analysed. On the basis of the baseline clinical data of patients included in this study, a risk prediction model for obstructive CAD was established by logistic regression.

RESULTS

(1) There were 592 patients in the CCTA group and 594 patients in the ICA group. The percentage of unnecessary ICA procedures was 7.5% in the CCTA group and 55.2% in the ICA group (P < 0.001), which was a decrease of 86.4%. (2) Eighteen patients in the CCTA group were readmitted for severe angina, 4 of whom underwent unplanned percutaneous coronary intervention (PCI). Eight patients in the ICA group were readmitted for severe angina, 2 of whom underwent unplanned PCI. There were no cardiac deaths, nonfatal myocardial infarctions or strokes in either group over the 1-year follow-up. There was no statistically significant difference in the rate of MACE-free survival between the two groups (97.0% vs. 98.7%, log-rankχ²=1.996, P = 0.158). (3) Allergic reactions to contrast agent were observed in 28 patients in the CCTA group and 16 in the ICA group (P = 0.190). (4) The median hospitalization cost in the CCTA group was $1259.54, and that in the ICA group was $1399.41, which was a significant difference (P < 0.001) and a decrease of 9.99%. (5) Based on the combination of the logistic regression forward selection method and backward elimination method, variables with P < 0.05, including creatinine, age, physical activity-induced symptoms, hyperlipidaemia, diabetes and smoking history, were selected from the baseline data of patients to predict obstructive CAD. The above variables were used to establish a risk prediction model for obstructive CAD. The area under the ROC curve (AUC) of this model was 0.721, indicating good predictive ability.

CONCLUSION

In patients with suspected CCS, including typical angina, atypical angina and nonangina chest pain with abnormal electrocardiogram results, the use of CCTA as a first-line diagnostic test can reduce the unnecessary incidence of ICA and hospitalization costs without increasing the incidence of MACE. A risk prediction model of obstructive CAD was established on the basis of the baseline data of the patients enrolled in this study, providing a clinical basis for the decision to use CCTA or ICA. Patients with a low probability of obstructive CAD can be given priority for CCTA, whereas patients with a high probability can be given priority for ICA.

Clinical utility of coronary CT angiography to guide PCI: a survey among P4 investigators

BACKGROUND

Coronary CT Angiography (CTA) is increasingly being used to plan percutaneous coronary intervention (PCI), offering detailed pre-procedural anatomical and physiological insights. The Precise Procedural and PCI Plan (P4) study evaluates the efficacy of CT- versus intravascular ultrasound-guided PCI. The aim of this study was to assess the utility of various CT-guided PCI tools and strategies as perceived by experienced operators within the context of the P4 study.

METHODS

A cross-sectional survey was conducted among 25 operators who participate in the P4 trial from multiple international centers. Participants were asked to evaluate the utility of pre-procedural CTA planning, physiological information with virtual PCI, and online guidance. The survey included multiple-choice, Likert scale, and ranking questions.

RESULTS

Most respondents valued pre-procedural planning highly (average score 2.83/3), particularly for the assessment of plaque composition and calcium characterization. Plaque composition evaluation, including calcium analysis, was ranked as the most valued factor, with an average usefulness score of 6.13/7. Calcium arc information was rated as the most useful component of calcium analysis (4/5 rating). The survey highlighted the importance of myocardial mass at risk assessment in bifurcation PCI and pointed to the anticipation of calcium density as a key future aspect of CT-guided PCI procedures.

CONCLUSIONS

The integration of CT-guided PCI promises to refine procedural planning and to pave the way for a new standard of care in patients with stable CAD.

Influence of virtual monoenergetic reconstructions on coronary CT angiography-based fractional flow reserve with photon-counting detector CT: intra-individual comparison with energy-integrating detector CT

OBJECTIVES

This study aimed to assess the impact of the photon-counting detector (PCD)-CT-based virtual monoenergetic image (VMI) reconstruction keV levels on CT-based fractional flow reserve (CT-FFR), compared to the energy-integrating detector (EID)-CT.

METHODS

Patients undergoing clinically indicated coronary CT angiography (CCTA) on an EID-CT were prospectively enrolled for a research CCTA on a PCD-CT within 30 days. PCD-CT datasets were reconstructed at VMI levels of 45, 55, 70, and 90 keV. CT-FFR was obtained semiautomatically using an on-site machine learning algorithm by two readers. CT-FFR ≤ 0.80 was considered hemodynamically significant.

RESULTS

A total of 20 patients (63.3 ± 8.8 years; 13 men (65%) were included. Median CT-FFR values in the per-vessel analysis for PCD-CT scans were 0.86 (0.81-0.92) for 45 keV, 0.87 (0.80-0.93) for 55 keV, 0.85 (0.79-0.92) for 70 keV and 0.82 (0.76-0.89) for 90 keV, and 0.86 (0.71-0.93) for EID-CT. Comparison among different VMIs showed significant differences only for 45 vs. 90 keV (p < 0.001), and 55 vs. 90 keV (p < 0.001). No significant differences were found in the pairwise comparison between any VMI and EID-CT (all p > 0.05). PCD-CT at 70 keV showed the highest correlation (r = 0.83, p < 0.001), agreement (ICC: 0.90 (0.84-0.94)), and the lowest bias (mean bias -0.01; limits of agreement, 0.84/0.94) when compared to EID-CT.

CONCLUSION

VMI reconstructions showed significant influence on CT-FFR values only at the extreme levels of the spectrum, while no significant differences were found in comparison with EID-CT. VMI at 70 keV demonstrates the highest correlation and agreement, with the lowest bias compared to EID-CT.

CRITICAL RELEVANCE STATEMENT

Evidence on novel spectral photon-counting detector (PCD)-CT's impact on CT-fractional flow reserve (FFR) is limited; our results demonstrate the feasibility of CT-FFR using PCD-CT, showing no significant differences between various virtual monoenergetic images and energy-integrating detector (EID)-CT values KEY POINTS: The impact of spectral photon-counting detector (PCD)-CT on CT-derived fractional flow reserve (CT-FFR) is unclear. Spectral PCD-CT-based CT-FFR is feasible, differing only at extreme virtual monoenergetic image levels. CT-FFR from PCD-CT at 70 keV showed the strongest correlation with energy-integrating detector-CT.

Diagnostic Performance and Clinical Impact of Photon-Counting Detector Computed Tomography in Coronary Artery Disease

BACKGROUND

Photon-counting detector-computed tomography (PCD-CT) has emerged as a promising technology, offering improved spatial resolution.

OBJECTIVES

This study aimed to evaluate the clinical impact and diagnostic performance of PCD-CT vs conventional energy-integrating detector computed tomography (EID-CT) for obstructive coronary artery disease (CAD).

METHODS

From 2022 to 2023, we retrospectively identified 7,833 consecutive patients who underwent clinically indicated coronary computed tomography angiography (CCTA) at a single center, with either PCD-CT (n = 3,876; NAEOTOM Alpha [Siemens Healthineers]) or EID-CT (n = 3,957; Revolution Apex 256 [GE HealthCare] or Aquilion ONE ViSION 320 [Canon Medical Systems]) scanners. Subsequent invasive coronary angiography (ICA) and percutaneous or surgical revascularization were performed as part of routine clinical care. Among those referred for ICA after coronary CTA, the presence of obstructive CAD in each vessel was determined by coronary CTA (severe stenosis on visual assessment per the Coronary Artery Disease Reporting and Data System) and ICA (≥50% diameter stenosis on quantitative coronary angiography) in a blinded fashion. The diagnostic performance of EID-CT and PCD-CT was compared by using quantitative coronary angiography as the reference standard.

RESULTS

Patients who underwent PCD-CT were less frequently referred to subsequent ICA than those undergoing EID-CT (9.9% vs 13.1%; P < 0.001). Among those who underwent ICA, revascularization was more frequently performed in the PCD-CT group than in the EID-CT group (43.4% vs 35.5%; P = 0.02). In the vessel-level analysis (n = 1,686), specificity (98.0% vs 93.0%; P < 0.001), positive predictive value (83.3% vs 63.0%; P = 0.002), and diagnostic accuracy (97.2% vs 92.8%; P < 0.001) were improved by PCD-CT. Sensitivity (90.9% vs 90.7%; P = 0.95) and negative predictive value (98.9% vs 98.7%; P = 0.83) for obstructive CAD were similar between the PCD-CT and EID-CT groups, respectively.

CONCLUSIONS

PCD-CT exhibited excellent diagnostic performance for detecting obstructive CAD. Compared with patients undergoing conventional EID-CT, fewer patients were referred to ICA after PCD-CT, but those referred were more likely to undergo revascularization.

Prognostic value of coronary plaque composition in symptomatic patients with obstructive coronary artery disease

OBJECTIVES

To determine whether plaque composition analysis defined by cardiac CT can provide incremental prognostic value above coronary artery disease (CAD) burden markers in symptomatic patients with obstructive CAD.

MATERIALS AND METHODS

Between 2009 and 2019, a multicentric registry included all consecutive symptomatic patients with obstructive CAD (at least one ≥ 50% stenosis on CCTA) and was followed for major adverse cardiovascular (MACE) defined by cardiovascular death or nonfatal myocardial infarction. Each coronary segment was scored visually for both the degree of stenosis and composition of plaque, which were classified as non-calcified, mixed, or calcified. To assess the prognostic value of each CCTA findings, different multivariable Cox regression models were used: model 1: clinical (traditional risk factors); model 2: model 1 + CAD burden (number of proximal segments with stenosis ≥ 50% + number of vessels with obstructive CAD); and model 3: model 2 + plaques feature (number of segments with non-calcified plaque).

RESULTS

Of 2312 patients (mean age 70 ± 12 years, 46% men), 319 experienced a MACE (13.8%) (median follow-up: 6.7 years (5.9-9.1)). The number of proximal segments with ≥ 50% stenosis, the number of vessels with obstructive CAD, and the number of segments with non-calcified plaque were all independently associated with MACEs (all p < 0.001). The addition of plaque composition analysis (model 3) showed the best improvement in model discrimination and reclassification (C-statistic improvement = 0.03; net reclassification improvement = 28.6%; integrative discrimination index = 5.4%, all p < 0.001).

CONCLUSIONS

In this population, the analysis of coronary plaque composition had an incremental prognostic value to predict MACEs above a model combining traditional risk factors and CAD burden.

KEY POINTS

Question Several coronary computed tomography angiography (CCTA) studies have shown the potential interest of plaque composition analysis, which can be further evaluated. Findings In symptomatic patients with obstructive coronary artery disease (CAD), plaque composition analysis had an incremental prognostic value above a model combining traditional risk factors and CAD burden. Clinical relevance In symptomatic patients with obstructive CAD, plaque composition analysis using CCTA has a strong incremental prognostic value above a model combining traditional risk factors and CAD burden, thus translating into a more accurate long-term major adverse cardiovascular event prediction.

Prognostic value of left ventricular mass measured on coronary computed tomography angiography

BACKGROUND

Left ventricular (LV) mass is a well-established prognostic indicator for cardiovascular risk. Measurement of LV mass on coronary computed tomography angiography (CCTA) is considered optional. We aimed to assess for associations between LV mass measured on CCTA with all-cause mortality (ACM) risk and to determine age- and sex-specific distributions.

METHODS

We evaluated patients without known coronary artery disease (CAD) who underwent CCTA at a single center. We assessed age- and sex-specific distributions (10th, 25th, 50th, 75th, and 90th percentiles) of LV mass index. ACM, the primary endpoint, was recorded over a median period of 5.1 [interquartile range: 1.4-8.4] years. The association between LV mass and mortality risk was assessed using multivariable Cox models adjusted for age, sex, medical history, coronary artery calcium (CAC) score and CCTA stenosis.

RESULTS

4187 patients (mean age: 61.9 ​± ​11.7, 63 ​% male) were included. Male sex, African American ethnicity, Hypertension, CAC>400, and smoking were independent predictors of increased LV mass index. During the median 5.1 years of study follow, 265 (6.3 ​%) deaths occurred. Increased LV mass index percentiles were associated with increased risk of ACM. The addition of LV mass index percentiles improved discrimination and reclassification for mortality prediction over a model with age, sex, conventional risk factors, CAC score and CCTA stenosis severity (X2 improvement: 22.68, NRI: 28 ​%, both p ​< ​0.001).

CONCLUSION

In a large sample of patients without known CAD who underwent CCTA, increased LV mass index provided independent and incremental prognostic value for all-cause mortality. Assessment of LV mass by CCTA, considering age and gender distribution, can be utilized clinically to identify patients with high myocardial mass.

Diagnostic performance of fully automatic coronary CT angiography-based quantitative flow ratio

BACKGROUND

Murray-law based quantitative flow ratio, namely μFR, was recently validated to compute fractional flow reserve (FFR) from coronary angiographic images in the cath lab. Recently, the μFR algorithm was applied to coronary computed tomography angiography (CCTA) and a semi-automated computed μFR (CT-μFR) showed good accuracy in identifying flow-limiting coronary lesions prior to referral of patients to the cath lab. We aimed to evaluate the diagnostic accuracy of an artificial intelligence-powered method for fully automatic CCTA reconstruction and CT-μFR computation, using cath lab physiology as reference standard.

METHODS

This was a post-hoc blinded analysis of the prospective CAREER trial (NCT04665817). Patients who underwent CCTA, coronary angiography including FFR within 30 days were included. Cath lab physiology standard for determining hemodynamically significant coronary stenosis was defined as FFR≤0.80, or μFR≤0.80 when FFR was not available.

RESULTS

Automatic CCTA reconstruction and CT-μFR computation was successfully achieved in 657 vessels from 242 patients. CT-μFR showed good correlation (r ​= ​0.62, p ​< ​0.001) and agreement (mean difference ​= ​-0.01 ​± ​0.10, p ​< ​0.001) with cath lab physiology standard. Patient-level diagnostic accuracy for CT-μFR to identify patients with hemodynamically significant stenosis was 83.0 ​% (95%CI: 78.3%-87.8 ​%), with sensitivity, specificity, positive and negative predictive value, positive and negative likelihood ratio of 84.2 ​%, 81.9 ​%, 82.1 ​%, 84.0 ​%, 4.7 and 0.2, respectively. Average analysis time for CT-μFR was 1.60 ​± ​0.34 ​min per patient.

CONCLUSION

The fully automatic CT-μFR yielded high feasibility and good diagnostic performance in identifying patients with hemodynamically significant stenosis prior to referral of patients to the cath lab.

CT myocardial perfusion and FFR-CT for the assessment of coronary artery disease

CT coronary angiography is the most reliable non-invasive imaging technique for ruling out coronary artery disease. However, its specificity is not high. Thus, when coronary stenosis of uncertain functional significance is detected, the recommendation is to perform complementary imaging tests to assess myocardial ischemia. CT myocardial perfusion imaging and CT fractional flow reserve provide added diagnostic accuracy and prognostic value to CT coronary angiography, by increasing its predictive value and facilitating therapeutic decision-making.

Patient Management Following Percutaneous Coronary Intervention

Percutaneous coronary intervention (PCI) is a mainstay procedure for the treatment of coronary artery disease. PCI techniques have evolved considerably since the advent of PCI in 1978, and with this evolution in techniques has come changes in the best practices for patient management following PCI. The objective of this review is to provide a comprehensive overview of key considerations in patient management following PCI. The long-term management of patients post-PCI should follow 3 main principles: 1) lifestyle modification and reduction of risk factors; 2) implementation of secondary prevention therapies; and 3) timely detection of restenosis. Best practices in achieving these principles include promotion of smoking cessation, regular physical activity, and a healthy diet, as well as blood pressure, diabetes mellitus, lipid, and weight management; prescription of secondary prevention therapies balancing ischemic and bleeding risk; and avoidance of routine surveillance for restenosis.

Cardiac biomarkers and CT coronary angiography for the assessment of coronary heart disease

Over the last 30 years, the widespread use of cardiac biomarkers has transformed the diagnostic evaluation of patients with coronary heart disease. Cardiac troponin is integral to the definition of acute myocardial infarction. High-sensitivity cardiac troponin (hs-cTn) assays can improve risk stratification to facilitate both the rapid rule out of myocardial infarction and prediction of future cardiovascular events. Numerous circulating biomarkers representing different pathological pathways improve prediction of atherosclerotic cardiovascular disease (ACVD) and coronary artery disease (CAD). In parallel, coronary computed tomography angiography (CCTA) has become the most widely used imaging modality for the evaluation of patients with possible angina. CCTA now allows for the quantification of coronary calcification, atherosclerotic plaque volume and different plaque characteristics, enabling the identification high-risk features and inflammation. In the future, the use of CCTA is likely to extend to risk stratification for the prevention of ACVD. As such, how to integrate these diagnostic and prognostic circulating and imaging biomarkers is a topic of considerable interest. This review aims to describe current status and future possibilities for the integration of CCTA and cardiac biomarker testing to improve the identification and treatment of individuals with coronary heart disease and heightened cardiovascular risk.

Extracellular Volume by Computed Tomography Is Useful for Prediction of Prognosis in Dilated Cardiomyopathy Cases with Heart Failure with Reduced Ejection Fraction

OBJECTIVE

Cardiac computed tomography (CT) helps screen coronary artery stenosis in cases with dilated cardiomyopathy (DCM). Extracellular volume fraction (ECV) analysis has recently been eligible for CT.

METHOD

We evaluated the impact of ECV on the CT to predict the prognosis in DCM patients with heart failure with reduced ejection fraction (HFrEF).

PATIENTS OR MATERIALS

We analyzed 101 consecutive DCM cases with HFrEF who underwent cardiac CT. All the patients had a lower left ventricular (LV) ejection fraction (LVEF) of less than 40%. We evaluated the effect of ECV to predict the patients' prognosis. Cardiovascular death, hospitalization due to heart failure, and fatal arrhythmic events were included in the major adverse cardiac events (MACE).

RESULTS

MACE occurred in 27 cases (27%). The patients with MACE (27 cases) had an increased ECV on the LVM on the CT (37.2 ± 6.7 vs. 32.2 ± 3.6%, p = 0.0008) compared to the others (74 cases). Based on the receiver operating characteristics curve analysis, the best cutoff value of the ECV on the LVM to predict the MACE was 32.3%. The patients with ECV ≥ 32.3% had significantly higher MACE based on the Kaplan-Meier analysis. The ECV on the LVM was a significant marker to predict MACE based on the univariate Cox proportional hazard model (hazard ratio of 8.00, 95% confidence interval 1.88-33.97, p = 0.0048).

CONCLUSIONS

ECV by CT is helpful to predict MACE in cases with DCM and HFrEF.

Cardiac CT, MRI, and PET in 2023: Exploration of Key Articles across Imaging and Multidisciplinary Journals

In this review, the authors examine recent advancements in noninvasive cardiac imaging, focusing on cardiac CT, MRI, and PET, reviewing key publications from imaging and multidisciplinary journals from 2023. The authors discuss the increasing adoption of photon-counting CT and its applications in coronary and structural imaging, and explore various aspects of plaque and functional assessment, emphasizing their clinical implications. Radiation exposure analysis from the SCOT-HEART (Scottish Computed Tomography of the Heart) trial is also discussed. The authors highlight the integration of artificial intelligence applications in cardiac imaging. Three-year follow-up data from the ADVANCE Registry are described, showcasing the potential of using artificial intelligence to improve diagnostic accuracy and patient outcomes in cardiovascular care. The authors explore the latest studies evaluating different cardiomyopathies using cardiac MRI. Radiologists' growing understanding of the brain-heart axis is presented through discussion of several studies. The authors also discuss the prognostic advantages of MRI over PET in patients with cardiac sarcoidosis. Finally, the authors outline society statements and guidelines from 2023 that are pertinent to cardiac imaging, offering a comprehensive review of current trends and applications in noninvasive imaging modalities.

Relationship Between Severity of Ischemia and Coronary Artery Disease for Different Stress Test Modalities in the ISCHEMIA Trial

BACKGROUND

The relationship between the extent and severity of stress-induced ischemia and the extent and severity of anatomic coronary artery disease (CAD) in patients with obstructive CAD is multifactorial and includes the intensity of stress achieved, type of testing used, presence and extent of prior infarction, collateral blood flow, plaque characteristics, microvascular disease, coronary vasomotor tone, and genetic factors. Among chronic coronary disease participants with site-determined moderate or severe ischemia, we investigated associations between ischemia severity on stress testing and the extent of CAD on coronary computed tomography angiography.

METHODS

Clinically indicated stress testing included nuclear imaging, echocardiography, cardiac magnetic resonance imaging, or nonimaging exercise tolerance test. Among those with preserved renal function who underwent coronary computed tomography angiography, we examined relationships between ischemia and CAD by coronary computed tomography angiography, overall, and by stress test modality, regardless of subsequent randomization. Core laboratories categorized ischemia as severe, moderate, mild, or none, while the extent and severity of anatomic CAD were categorized based on the modified Duke prognostic index.

RESULTS

Among 3601 participants with interpretable stress tests and coronary computed tomography angiography, ischemia severity was weakly associated with CAD extent/severity (r=0.27), with modest variability in strength of association by modality: nuclear (n=1532; r=0.40), echocardiography (n=827; r=0.15), cardiac magnetic resonance imaging (n=108; r=0.31), and exercise tolerance test (n=1134; r=0.18). The extent of infarction on nuclear imaging and echocardiography was weakly associated with CAD extent/severity.

CONCLUSIONS

Overall, ischemia severity on stress testing showed weak to moderate associations with the anatomic extent of CAD in this cohort with moderate or severe ischemia on local interpretation and controlled symptoms.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01471522.

Scarpa Matuck B, Yang W, Qin L, Yan F, Lima JAC, Arbab-Zadeh A, Wolfe S. Prognostic Value of Coronary CT Angiography-Derived Quantitative Flow Ratio in Suspected Coronary Artery Disease

Background The prognostic value of coronary CT angiography (CTA)-derived quantitative flow ratio (CT-QFR) remains unknown. Purpose To determine the prognostic value of CT-QFR in predicting the long-term outcomes of patients with suspected coronary artery disease (CAD) in comparison with invasive coronary angiography (ICA)/SPECT and to determine the influence of prior percutaneous coronary intervention (PCI) on the prognostic value of CT-QFR. Materials and Methods In this secondary analysis of the prospective international CORE320 study, 379 participants who underwent coronary CTA and SPECT within 60 days before ICA between November 2009 and July 2011 were included for follow-up. The coronary CTA images were analyzed to determine CT-QFR. The primary outcome was major adverse cardiovascular events (MACEs) in the 5-year follow-up. Kaplan-Meier curves, multivariable Cox regression models adjusted for clinical variables, and areas under the receiver operating characteristic curves (AUCs) were used to assess and compare the predictive ability of CT-QFR and ICA/SPECT. Results CT-QFR computation and 5-year follow-up data were available for 310 participants (median age, 62 years), of whom 205 (66%) were male. CT-QFR (hazard ratio, 1.9 [95% CI: 1.0, 3.5]; P = .04) and prior myocardial infarction (hazard ratio, 2.5 [95% CI: 1.5, 4.0]; P < .001) were independent predictors of MACE occurrence in the 5-year follow-up. MACE-free survival rates were similar in participants with normal CT-QFR and ICA/SPECT (82% vs 80%; P = .45) and in participants with abnormal CT-QFR and ICA/SPECT findings (60% vs 57%; P = .40). In participants with prior PCI, CT-QFR had a lower AUC in predicting MACEs than in participants without prior PCI (0.44 vs 0.70; P < .001). Conclusion CT-QFR was an independent predictor of MACEs in the 5-year follow-up in participants with suspected CAD and showed similar 5-year prognostic value to ICA/SPECT; however, prior PCI affected CT-QFR ability to predict MACEs. Clinical trial registration no. NCT00934037 © RSNA, 2024 Supplemental material is available for this article.

Diagnostic Performance of AI-enabled Plaque Quantification from Coronary CT Angiography Compared with Intravascular Ultrasound

Purpose To assess the diagnostic performance of a coronary CT angiography (CCTA) artificial intelligence (AI)-enabled tool (AI-QCPA; HeartFlow) to quantify plaque volume, as compared with intravascular US (IVUS). Materials and Methods A retrospective subanalysis of a single-center prospective registry study was conducted in participants with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention of the culprit vessel. Participants with greater than 50% stenosis in nonculprit vessels underwent CCTA, invasive coronary angiography, and IVUS of nonculprit lesion(s) between 2 and 40 days after primary percutaneous coronary intervention. Comparisons of plaque volumes obtained using AI-QCPA (HeartFlow) and IVUS were assessed using Spearman rank correlation (ρ) and Bland-Altman analysis. Results Thirty-three participants (mean age, 59.1 years ± 8.8 [SD]; 27 [82%] male and six [18%] female participants) and 67 vessels were included for analysis. There was strong agreement between AI-QCPA and IVUS in vessel (ρ = 0.94) and lumen volumes (ρ = 0.97). High agreement between AI-QCPA and IVUS was also found for total plaque volume (ρ = 0.92), noncalcified plaque (ρ = 0.91), and calcified plaque (ρ = 0.87). Bland-Altman analysis demonstrated AI-QCPA underestimated total plaque volume (-9.4 mm3) and calcified plaque (-11.4 mm3) and overestimated for noncalcified plaque (2.0 mm3) when compared with IVUS. Conclusion An AI-enabled automated plaque quantification tool for CCTA had high agreement with IVUS for quantifying plaque volume and characterizing plaque. Keywords: Coronary Plaque, Intravascular US, Coronary CT Angiography, Artificial Intelligence Supplemental material is available for this article. ClinicalTrials.gov registration no. NCT02926755 © RSNA, 2024.

Diagnostic Accuracy of Dynamic Stress Myocardial CT Perfusion Compared with Invasive Physiology in Patients with Stents: The Advantage 2 Study

Background The detection of in-stent restenosis (ISR) with coronary CT angiography (CCTA) is challenging, but CT perfusion (CTP) has demonstrated improved diagnostic accuracy over CCTA in patients with stents. However, there are limited data on the performance of dynamic CTP, which allows noninvasive adjudication of regional myocardial blood flow. Purpose To compare the diagnostic performance of regadenoson-stress dynamic CTP with that of CCTA, using fractional flow reserve (FFR) and the index of microvascular resistance (IMR) as reference standards for epicardial coronary circulation and coronary microcirculation, respectively. Materials and Methods Between January 2021 and June 2022, this prospective study enrolled patients with stents with indication for invasive coronary angiography due to suspicion of ISR or coronary artery disease progression. Participants underwent dynamic stress myocardial CTP and rest CTP plus CCTA. A wide coverage (z-axis coverage, 16 cm) and fast (gantry rotation time, 0.28 second) scanner was used. During invasive coronary angiography, FFR and IMR were obtained. The diagnostic rate (number of interpretable territories divided by number of evaluated territories) and accuracy of CCTA and CTP were evaluated in a territory-based analysis and compared with FFR and IMR (primary end points of the study). Results The study included 156 consecutive patients (136 men [87%]; mean age, 63.1 years ± 8.2 [SD]) with 504 stents. The diagnostic rate was higher for CTP than for CCTA (98.7% [789 of 799 territories] vs 95.6% [764 of 799 territories], P < .001). With use of FFR as the reference standard, sensitivity, specificity, and diagnostic accuracy were higher for CTP than for CCTA (89.0%, 82.8%, and 84.7%, respectively, vs 60.0%, 61.9%, and 61.5%; P < .001). With use of IMR as the reference standard, sensitivity, specificity, and diagnostic accuracy were higher with CTP than with CCTA (76.5%, 85.9%, and 82.9%, respectively, vs 48.2%, 63.5%, and 59.3%; P < .01). The mean effective dose of stress CTP plus CCTA was 10.4 mSv ± 2.7. Conclusion In patients with coronary stents, dynamic CTP improves the diagnostic performance of CCTA in the detection of territory-based ischemia. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Williams in this issue.

Computed tomography and coronary artery calcium score for screening of coronary artery disease and cardiovascular risk management in asymptomatic individuals

Several risk prediction models exist to predict atherosclerotic cardiovascular disease in asymptomatic individuals, but systematic reviews have generally found these models to be of limited utility. The coronary artery calcium score (CACS) offers an improvement in risk prediction, yet its role remains contentious. Notably, its negative predictive value has a high ability to rule out clinically relevant atherosclerotic cardiovascular disease. Nonetheless, CACS 0 does not permanently reclassify to a lower cardiovascular risk and periodic reassessment every 5 to 10 years remains necessary. Conversely, elevated CACS (> 100 or > 75th percentile adjusted for age, sex and ethnicity) can reclassify intermediate-risk individuals to a high risk, benefiting from preventive medication. The forthcoming update to the Dutch cardiovascular risk management guideline intends to re-position CACS for cardiovascular risk assessment as such in asymptomatic individuals. Beyond CACS as a single number, several guidelines recommend coronary CT angiography (CCTA), which provides additional information about luminal stenosis and (high-risk) plaque composition, as the first choice of test in symptomatic patients and high-risk patients. Ongoing randomised studies will have to determine the value of atherosclerosis evaluation with CCTA for primary prevention in asymptomatic individuals.

Real-world evidence study on the impact of SPECT MPI, PET MPI, cCTA and stress echocardiography on downstream healthcare utilisation in patients with coronary artery disease in the US

BACKGROUND

Coronary artery disease (CAD) is associated with a large clinical and economic burden. However, consensus on the optimal approach to CAD diagnosis is lacking. This study sought to compare downstream healthcare resource utilisation following different cardiac imaging modalities, to inform test selection for CAD diagnosis.

METHODS

Claims and electronic health records data from the Decision Resources Group Real-World Evidence US Data Repository were analysed for 2.5 million US patients who underwent single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI), positron emission tomography myocardial perfusion imaging (PET MPI), coronary computed tomography angiography (cCTA), or stress echocardiography between January 2016 and March 2018. Patients were stratified into nine cohorts based on suspected or existing CAD diagnosis, pre-test risk, and prior events or interventions. Downstream healthcare utilisation, including additional diagnostic imaging, coronary angiography, and cardiac-related health system encounters, was compared by cohort and index imaging modality.

RESULTS

Among patients with suspected CAD diagnosed within 3 months of the index test, PET MPI was associated with lower downstream utilisation; 25-37% of patients who underwent PET MPI required additional downstream healthcare resources compared with 40-49% of patients who received SPECT MPI, 35-41% of patients who underwent cCTA, and 44-47% of patients who received stress echocardiography. Patients who underwent PET MPI experienced fewer acute cardiac events (5.3-9.4%) and generally had lower rates of healthcare encounters (0.8-4.1%) and invasive coronary angiography (ICA, 15.4-24.2%) than those who underwent other modalities. SPECT MPI was associated with more downstream ICA (31.3-38.2%) and a higher rate of cardiac events (9.5-13.2%) compared with PET MPI (5.3-9.4%) and cCTA (6.9-9.9%). Across all cohorts, additional diagnostic imaging was 1.6 to 4.7 times more frequent with cCTA compared with PET MPI.

CONCLUSION

Choice of imaging modality for CAD diagnosis impacts downstream healthcare utilisation. PET MPI was associated with lower utilisation across multiple metrics compared with other imaging modalities studied.

Intra-Atrial Right Coronary Artery: A Condition Revealed by Coronary CT Scan

Coronary artery anomalies are rare and may involve the coronary origin, course, or termination. Most are benign; however, some can lead to myocardial damage, sudden death, or potential hazards during interventional or surgical procedures. The advancement of imaging studies has led to an increase in their diagnosis. Coronary computed tomography angiography (CCTA) especially has characterized new anomalies that were previously anecdotal. This is the case of the intra-atrial course of the right coronary artery. The present is a brief review about this rare congenital anomaly.

Effect of acute intravenous beta-blocker administration on myocardial blood flow during same-day hybrid CCTA/PET imaging

This study aimed to evaluate the impact of acute intravenous beta-blocker administration on myocardial blood flow (MBF) during same-day hybrid coronary computed tomography angiography (CCTA) and 13N-ammonia positron emission tomography (PET) myocardial perfusion imaging (MPI). Previous research on the discontinuation of oral beta-blockers before MPI has shown mixed results, with no studies yet exploring the acute intravenous administration in the context of same-day hybrid imaging. This retrospective study included patients with suspected chronic coronary syndromes undergoing same-day hybrid CCTA/13N-ammonia PET MPI. Exclusion criteria comprised coronary artery stenosis ≥ 50% or regional perfusion abnormalities on PET, and baseline oral beta-blocker medication. Intravenous metoprolol (up to 30 mg) was administered as needed for heart rate control before CCTA. MBF measurements were obtained at rest (rMBF) and during stress (sMBF), and myocardial flow reserve (MFR) was calculated. After excluding 281 patients, 154 were eligible for propensity-score matching, resulting in 108 patients divided into two equal groups based on beta-blocker administration. The groups showed no significant differences in baseline characteristics. Among those who received beta-blockers, there was a significant decrease in sMBF (2.21 [IQR 1.72-2.78] versus 2.46 [2.08-2.99] ml∙min-1∙g-1, p = 0.027) and MFR (3.46 [2.70-4.05] versus 3.79 [3.22-4.46], p = 0.030), respectively, compared to those who did not receive beta-blockers. In contrast, rMBF remained unaffected (0.65 [0.54-0.78] versus 0.64 [0.55-0.76] ml∙min-1∙g-1, p = 0.931). Acute intravenous beta-blocker administration significantly impacts MBF, leading to a slight reduction in sMBF and MFR. In contrast, rMBF appears unaffected, suggesting that beta-blockers primarily affect the coronary capacity to respond to vasodilators.

Non-Invasive Assessment of Coronary Microvascular Dysfunction Using Vascular Deformation-Based Flow Estimation

OBJECTIVE

Non-invasive computation of the index of microcirculatory resistance from coronary computed tomography angiography (CTA), referred to as IMR[Formula: see text], is a promising approach for quantitative assessment of coronary microvascular dysfunction (CMD). However, the computation of IMR[Formula: see text] remains an important unresolved problem due to its high requirement for the accuracy of coronary blood flow. Existing CTA-based methods for estimating coronary blood flow rely on physiological assumption models to indirectly identify, which leads to inadequate personalization of total and vessel-specific flow.

METHODS

To overcome this challenge, we propose a vascular deformation-based flow estimation (VDFE) model to directly estimate coronary blood flow for reliable IMR[Formula: see text] computation. Specifically, we extract the vascular deformation of each vascular segment from multi-phase CTA. The concept of inverse problem solving is applied to implicitly derive coronary blood flow based on the physical constraint relationship between blood flow and vascular deformation. The vascular deformation constraints imposed on each segment within the vascular structure ensure sufficient individualization of coronary blood flow.

RESULTS

Experimental studies on 106 vessels collected from 89 subjects demonstrate the validity of our VDFE, achieving an IMR[Formula: see text] accuracy of 82.08 %. The coronary blood flow estimated by VDFE has better reliability than the other four existing methods.

CONCLUSION

Our proposed VDFE is an effective approach to non-invasively compute IMR[Formula: see text] with excellent diagnostic performance.

SIGNIFICANCE

The VDFE has the potential to serve as a safe, effective, and cost-effective clinical tool for guiding CMD clinical treatment and assessing prognosis.

ESR Essentials: imaging in stable chest pain - practice recommendations by ESCR

Stable chest pain is a common symptom with multiple potential causes. Non-invasive imaging has an important role in diagnosis and guiding management through the assessment of coronary stenoses, atherosclerotic plaque, myocardial ischaemia or infarction, and cardiac function. Computed tomography (CT) provides the anatomical evaluation of coronary artery disease (CAD) with the assessment of stenosis, plaque type and plaque burden, with additional functional information available from CT fractional flow reserve (FFR) or CT myocardial perfusion imaging. Stress magnetic resonance imaging, nuclear stress myocardial perfusion imaging, and stress echocardiography can assess myocardial ischaemia and other cardiac functional parameters. Coronary CT angiography can be used as a first-line test for many patients with stable chest pain, particularly those with low to intermediate pre-test probability. Functional testing may be considered for patients with known CAD, where the clinical significance is uncertain based on anatomical testing, or in patients with high pre-test probability. This practice recommendations document can be used to guide the selection of non-invasive imaging for patients with stable chest pain and provides brief recommendations on how to perform and report these diagnostic tests. KEY POINTS: The selection of non-invasive imaging tests for patients with stable chest pain should be based on symptoms, pre-test probability, and previous history. Coronary CT angiography can be used as a first-line test for many patients with stable chest pain, particularly those with low to intermediate pre-test probability. Functional testing can be considered for patients with known CAD, where the clinical significance of CAD is uncertain based on anatomical testing, or in patients with high pre-test probability. KEY RECOMMENDATIONS: Non-invasive imaging is an important part of the assessment of patients with stable chest pain. The selection of non-invasive imaging test should be based on symptoms, pre-test probability, and previous history. (Level of evidence: High). Coronary CT angiography can be used as a first line test for many patients with stable chest pain, particularly those with low to intermediate pre-test probability. CT provides information on stenoses, plaque type, plaque volume, and if required functional information with CT fractional flow reserve or CT perfusion. (Level of evidence: High). Functional testing can be considered for patients with known CAD, where the clinical significance of CAD is uncertain based on anatomical testing, or in patients with high pre-test probability. Stress MRI, SPECT, PET, and echocardiography can provide information on myocardial ischemia, along with cardiac functional and other information. (Level of evidence: Medium).

Patient-Specific Numerical Simulations of Coronary Artery Hemodynamics and Biomechanics: A Pathway to Clinical Use

PURPOSE

Numerical models that simulate the behaviors of the coronary arteries have been greatly improved by the addition of fluid-structure interaction (FSI) methods. Although computationally demanding, FSI models account for the movement of the arterial wall and more adequately describe the biomechanical conditions at and within the arterial wall. This offers greater physiological relevance over Computational Fluid Dynamics (CFD) models, which assume the walls do not move or deform. Numerical simulations of patient-specific cases have been greatly bolstered by the use of imaging modalities such as Computed Tomography Angiography (CTA), Magnetic Resonance Imaging (MRI), Optical Coherence Tomography (OCT), and Intravascular Ultrasound (IVUS) to reconstruct accurate 2D and 3D representations of artery geometries. The goal of this study was to conduct a comprehensive review on CFD and FSI models on coronary arteries, and evaluate their translational potential.

METHODS

This paper reviewed recent work on patient-specific numerical simulations of coronary arteries that describe the biomechanical conditions associated with atherosclerosis using CFD and FSI models. Imaging modality for geometry collection and clinical applications were also discussed.

RESULTS

Numerical models using CFD and FSI approaches are commonly used to study biomechanics within the vasculature. At high temporal and spatial resolution (compared to most cardiac imaging modalities), these numerical models can generate large amount of biomechanics data.

CONCLUSIONS

Physiologically relevant FSI models can more accurately describe atherosclerosis pathogenesis, and help to translate biomechanical assessment to clinical evaluation.

Intra-individual comparison of epicardial adipose tissue characteristics on coronary CT angiography between photon-counting detector and energy-integrating detector CT systems

PURPOSE

To explore the potential differences in epicardial adipose tissue (EAT) volume and attenuation measurements between photon-counting detector (PCD) and energy-integrating detector (EID)-CT systems.

METHODS

Fifty patients (mean age 69 ± 8 years, 41 male [82 %]) were prospectively enrolled for a research coronary CT angiography (CCTA) on a PCD-CT within 30 days after clinical EID-based CCTA. EID-CT acquisitions were reconstructed using a Bv40 kernel at 0.6 mm slice thickness. The PCD-CT acquisition was reconstructed at a down-sampled resolution (0.6 mm, Bv40; [PCD-DS]) and at ultra-high resolutions (PCD-UHR) with a 0.2 mm slice thickness and Bv40, Bv48, and Bv64 kernels. EAT segmentation was performed semi-automatically at about 1 cm intervals and interpolated to cover the whole epicardium within a threshold of -190 to -30 HU. A subgroup analysis was performed based on quartile groups created from EID-CT data and PCD-UHRBv48 data. Differences were measured using repeated-measures ANOVA and the Friedman test. Correlations were tested using Pearson's and Spearman's rho, and agreement using Bland-Altman plots.

RESULTS

EAT volumes significantly differed between some reconstructions (e.g.

EID-CT

138 ml [IQR 100, 188]; PCD-DS: 147 ml [110, 206]; P<0.001). Overall, correlations between PCD-UHR and EID-CT EAT volumes were excellent, e.g. PCD-UHRBv48: r: 0.976 (95 % CI: 0.958, 0.987); P<0.001; with good agreement (mean bias: -9.5 ml; limits of agreement [LoA]: -40.6, 21.6). On the other hand, correlations regarding EAT attenuation was moderate, e.g. PCD-UHRBV48: r: 0.655 (95 % CI: 0.461, 0.790); P<0.001; mean bias: 6.5 HU; LoA: -2.0, 15.0.

CONCLUSION

EAT attenuation and volume measurements demonstrated different absolute values between PCD-UHR, PCD-DS as well as EID-CT reconstructions, but showed similar tendencies on an intra-individual level. New protocols and threshold ranges need to be developed to allow comparison between PCD-CT and EID-CT data.

Association between Pericoronary Fat Attenuation Index Values and Plaque Composition Volume Fraction Measured by Coronary Computed Tomography Angiography

RATIONALE AND OBJECTIVES

The pericoronary fat attenuation index (FAI) values around plaques may reveal the relationship between periplaque vascular inflammation and different plaque component volume fractions. We aimed to evaluate the potential associations between periplaque FAI values and plaque component volume fractions.

MATERIALS AND METHODS

496 patients (1078 lesions) with coronary artery disease, who underwent computed tomography angiography (CCTA) between September 2022 and August 2023, were analyzed retrospectively. Each lesion was characterized and the plaque component volume fractions and periplaque FAI values were measured. Multiple linear regression, weighted quantile sum (WQS) regression, and quantile g-computation (Qgcomp) were used to explore the relationship between plaque component volume fractions and the risk of elevated periplaque FAI values.

RESULTS

After adjusting for clinical characteristics, multiple linear regression identified that lipid components volume fraction (β = 0.162, P < 0.001) were independent risk factors for elevated periplaque FAI values whereas calcified components volume fraction (β = -0.066, P = 0.025) were independent protective factors. The WQS regression models indicated an increase in the overall confounding effect of the adjusted lipid indices and plaque composition volume fraction on the risk of elevated periplaque FAI values (P = 0.004). Qgcomp analysis indicated lipid component volume fraction and calcified component volume fraction was positively and negatively correlated with elevated plaque FAI values, respectively (all P < 0.05).

CONCLUSIONS

Periplaque FAI values quantified by CCTA were strongly correlated with lipid and calcification component volume fractions.

Ultra-high-resolution CT vs. invasive angiography for detecting hemodynamically significant coronary artery disease: Rationale and methods of the CORE-PRECISION multicenter study

BACKGROUND

Direct coronary arterial evaluation via computed tomography (CT) angiography is the most accurate noninvasive test for the diagnosis of coronary artery disease (CAD). However, diagnostic accuracy is limited in the setting of severe coronary calcification or stents. Ultra-high-resolution CT (UHR-CT) may overcome this limitation, but no rigorous study has tested this hypothesis.

METHODS

The CORE-PRECISION is an international, multicenter, prospective diagnostic accuracy study testing the non-inferiority of UHR-CT compared to invasive coronary angiography (ICA) for identifying patients with hemodynamically significant CAD. The study will enroll 150 patients with history of CAD, defined as prior documentation of lumen obstruction, stenting, or a calcium score ≥400, who will undergo UHR-CT before clinically prompted ICA. Assessment of hemodynamically significant CAD by UHR-CT and ICA will follow clinical standards. The reference standard will be the quantitative flow ratio (QFR) with <0.8 defined as abnormal. All data will be analyzed in independent core laboratories.

RESULTS

The primary outcome will be the comparative diagnostic accuracy of UHR-CT vs. ICA for detecting hemodynamically significant CAD on a patient level. Secondary analyses will focus on vessel level diagnostic accuracy, quantitative stenosis analysis, automated contour detection, in-depth plaque analysis, and others.

CONCLUSION

CORE-PRECISION aims to investigate if UHR-CT is non-inferior to ICA for detecting hemodynamically significant CAD in high-risk patients, including those with severe coronary calcification or stents. We anticipate this study to provide valuable insights into the utility of UHR-CT in this challenging population and for its potential to establish a new standard for CAD assessment.

Optimizing Coronary Computed Tomography Angiography Using a Novel Deep Learning-Based Algorithm

Coronary computed tomography angiography (CCTA) is an essential part of the diagnosis of chronic coronary syndrome (CCS) in patients with low-to-intermediate pre-test probability. The minimum technical requirement is 64-row multidetector CT (64-MDCT), which is still frequently used, although it is prone to motion artifacts because of its limited temporal resolution and z-coverage. In this study, we evaluate the potential of a deep-learning-based motion correction algorithm (MCA) to eliminate these motion artifacts. 124 64-MDCT-acquired CCTA examinations with at least minor motion artifacts were included. Images were reconstructed using a conventional reconstruction algorithm (CA) and a MCA. Image quality (IQ), according to a 5-point Likert score, was evaluated per-segment, per-artery, and per-patient and was correlated with potentially disturbing factors (heart rate (HR), intra-cycle HR changes, BMI, age, and sex). Comparison was done by Wilcoxon-Signed-Rank test, and correlation by Spearman's Rho. Per-patient, insufficient IQ decreased by 5.26%, and sufficient IQ increased by 9.66% with MCA. Per-artery, insufficient IQ of the right coronary artery (RCA) decreased by 18.18%, and sufficient IQ increased by 27.27%. Per-segment, insufficient IQ in segments 1 and 2 decreased by 11.51% and 24.78%, respectively, and sufficient IQ increased by 10.62% and 18.58%, respectively. Total artifacts per-artery decreased in the RCA from 3.11 ± 1.65 to 2.26 ± 1.52. HR dependence of RCA IQ decreased to intermediate correlation in images with MCA reconstruction. The applied MCA improves the IQ of 64-MDCT-acquired images and reduces the influence of HR on IQ, increasing 64-MDCT validity in the diagnosis of CCS.

Enhancing diagnostic performance and image quality in coronary CT angiography: Impact of SnapShot Freeze 2 algorithm across varied heart rates in stent patients

PURPOSE

To investigate the enhancement of image quality achieved through the utilization of SnapShot Freeze 2 (SSF2), a comparison was made against the results obtained from the original SnapShot Freeze algorithm (SSF) and standard motion correction (STND) in stent patients undergoing coronary CT angiography (CCTA) across the entire range of heart rates.

MATERIALS AND METHODS

A total of 118 patients who underwent CCTA, were retrospectively included in this study. Images of these patients were reconstructed using three different algorithms: SSF2, SSF, and STND. Objective assessments include signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), diameters of stents and artifact index (AI). The image quality was subjectively evaluated by two readers.

RESULTS

Compared with SSF and STND, SSF2 had similar or even higher quality in the parameters (AI, SNR, CNR, inner diameters) of coronary artery, stent, myocardium, MV (mitral valve), TV (tricuspid valve), AV (aorta valve), and PV (pulmonary valve), and aortic root (AO). Besides the above structures, SSF2 also demonstrated comparable or even higher subjective scores in atrial septum (AS), ventricular septum (VS), and pulmonary artery root (PA). Furthermore, the enhancement in image quality with SSF2 was significantly greater in the high heart rate group compared to the low heart rate group. Moreover, the improvement in both high and low heart rate groups was better in the SSF2 group compared to the SSF and STND group. Besides, when using the three algorithms, an effect of heart rate variability on stent image quality was not detected.

CONCLUSION

Compared to SSF and STND, SSF2 can enhance the image quality of whole-heart structures and mitigate artifacts of coronary stents. Furthermore, SSF2 has demonstrated a significant improvement in the image quality for patients with a heart rate equal to or higher than 85 bpm.

Diagnostic Modalities in Heart Failure: A Narrative Review

Heart failure (HF) can present acutely or progress over time. It can lead to morbidity and mortality affecting 6.5 million Americans over the age of 20. The HF type is described according to the ejection fraction classification, defined as the percentage of blood volume that exits the left ventricle after myocardial contraction, undergoing ejection into the circulation, also called stroke volume, and is proportional to the ejection fraction. Cardiac catheterization is an invasive procedure to evaluate coronary artery disease leading to HF. Several biomarkers are being studied that could lead to early detection of HF and better symptom management. Testing for various biomarkers in the patient's blood is instrumental in confirming the diagnosis and elucidating the etiology of HF. There are various biomarkers elevated in response to increased myocardial stress and volume overload, including B-type natriuretic peptide (BNP) and its N-terminal prohormone BNP. We explored online libraries such as PubMed, Google Scholar, and Cochrane to find relevant articles. Our narrative review aims to extensively shed light on diagnostic modalities and novel techniques for diagnosing HF.

Efficacy of Diagnostic Testing of Suspected Coronary Artery Disease: A Contemporary Review

BACKGROUND

Coronary artery disease (CAD) is a highly prevalent condition which can lead to myocardial ischemia as well as acute coronary syndrome. Early diagnosis of CAD can improve patient outcomes through guiding risk factor modification and treatment modalities.

SUMMARY

Testing for CAD comes with increased cost and risk; therefore, physicians must determine which patients require testing, and what testing modality will offer the most useful data to diagnose patients with CAD. Patients should have an initial risk stratification for pretest probability of CAD based on symptoms and available clinical data. Patients with a pretest probability less than 5% should receive no further testing, while patients with a high pretest probability should be considered for direct invasive coronary angiography. In patients with a pretest probability between 5 and 15%, coronary artery calcium score and or exercise electrocardiogram can be obtained to further risk stratify patients to low-risk versus intermediate-high-risk. Intermediate-high-risk patients should be tested with coronary computed tomography angiography (preferred) versus positron emission tomography or single photon emission computed tomography based on their individual patient characteristics and institutional availability.

KEY MESSAGES

This comprehensive review aimed to describe the available CAD testing modalities, detail their risks and benefits, and propose when each should be considered in the evaluation of a patient with suspected CAD.

BACKGROUND

Coronary artery disease (CAD) is a highly prevalent condition which can lead to myocardial ischemia as well as acute coronary syndrome. Early diagnosis of CAD can improve patient outcomes through guiding risk factor modification and treatment modalities.

SUMMARY

Testing for CAD comes with increased cost and risk; therefore, physicians must determine which patients require testing, and what testing modality will offer the most useful data to diagnose patients with CAD. Patients should have an initial risk stratification for pretest probability of CAD based on symptoms and available clinical data. Patients with a pretest probability less than 5% should receive no further testing, while patients with a high pretest probability should be considered for direct invasive coronary angiography. In patients with a pretest probability between 5 and 15%, coronary artery calcium score and or exercise electrocardiogram can be obtained to further risk stratify patients to low-risk versus intermediate-high-risk. Intermediate-high-risk patients should be tested with coronary computed tomography angiography (preferred) versus positron emission tomography or single photon emission computed tomography based on their individual patient characteristics and institutional availability.

KEY MESSAGES

This comprehensive review aimed to describe the available CAD testing modalities, detail their risks and benefits, and propose when each should be considered in the evaluation of a patient with suspected CAD.

Non-ST-elevation acute coronary syndromes with previous coronary artery bypass grafting: a meta-analysis of invasive vs. conservative management

BACKGROUND AND AIMS

A routine invasive strategy is recommended in the management of higher risk patients with non-ST-elevation acute coronary syndromes (NSTE-ACSs). However, patients with previous coronary artery bypass graft (CABG) surgery were excluded from key trials that informed these guidelines. Thus, the benefit of a routine invasive strategy is less certain in this specific subgroup.

METHODS

A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted. A comprehensive search was performed of PubMed, EMBASE, Cochrane, and ClinicalTrials.gov. Eligible studies were RCTs of routine invasive vs. a conservative or selective invasive strategy in patients presenting with NSTE-ACS that included patients with previous CABG. Summary data were collected from the authors of each trial if not previously published. Outcomes assessed were all-cause mortality, cardiac mortality, myocardial infarction, and cardiac-related hospitalization. Using a random-effects model, risk ratios (RRs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Summary data were obtained from 11 RCTs, including previously unpublished subgroup outcomes of nine trials, comprising 897 patients with previous CABG (477 routine invasive, 420 conservative/selective invasive) followed up for a weighted mean of 2.0 (range 0.5-10) years. A routine invasive strategy did not reduce all-cause mortality (RR 1.12, 95% CI 0.97-1.29), cardiac mortality (RR 1.05, 95% CI 0.70-1.58), myocardial infarction (RR 0.90, 95% CI 0.65-1.23), or cardiac-related hospitalization (RR 1.05, 95% CI 0.78-1.40).

CONCLUSIONS

This is the first meta-analysis assessing the effect of a routine invasive strategy in patients with prior CABG who present with NSTE-ACS. The results confirm the under-representation of this patient group in RCTs of invasive management in NSTE-ACS and suggest that there is no benefit to a routine invasive strategy compared to a conservative approach with regard to major adverse cardiac events. These findings should be validated in an adequately powered RCT.