Assessment Of Coronary Plaques Research Articles

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

Abstract Background Characterization of atherosclerotic plaque features by coronary computed tomography angiography (CCTA) carries profound prognostic value. Previous studies indicate that coronary plaque burden and certain plaque features are associated to lesion-specific ischemia by invasive fractional flow reserve (FFR). However, the existing literature is limited by small sample sizes, and provide inconsistent results. Purpose We performed a meta-analysis in order to delineate further the potential association between coronary plaque phenotype by CCTA and FFR. Methods A comprehensive systematic literature review and meta-analysis was conducted. PubMed and Embase databases were searched for studies that investigated the association between coronary plaque characteristics and FFR between January 2010 and August 2023. Study search, evaluation, and data extraction were performed independently by two researchers. Weighted mean difference (WMD) method for WMD was used for comparison of pooled per-lesion plaque parameters and presence of specific plaque features against presence of lesion-specific ischemia (FFR ≤0.80). Lesions with stenosis severity of 25-90% were included. Extracted data from eligible studies were analysed using random effects model for WMD and to estimate odds ratios (OR) with 95% confidence intervals (CI). Results A total of 12 studies were deemed eligible with 1,318 patients and available data on 1,915 coronary lesions. Of these, 626 lesions caused ischemia. Significantly greater total plaque volume (TPV) and non-calcified plaque volume (NCPV) occurred in lesions with abnormal FFR compared to normal FFR (WMD 83.0 mm3, 95% CI: 44.27; 121.81, p<0.001; WMD 83.63 mm3, 95% CI: 55.0; 112.24, p <0.001, respectively). Similar findings were observed for aggregate plaque volume (%APV) and plaque burden (%PB) with WMD 9.18, 95% CI: 6.08; 12.28, p<0.001; WMD 8.83, 95% CI: 4.32; 14.24, p=0.001, respectively. Napkin ring-sign and spotty calcification appeared more frequent in ischemia-causing lesions compared to those with FFR >0.80 (OR 4.25, 95% CI: 1.39; 13.00, p=0.011; OR 1.92, 95% CI: 1.33; 2.75, p=0.001, respectively). A summary of the meta-analysis findings regarding the association between plaque burden and plaque characteristics and FFR is provided in Figure 1 and 2. Conclusion CCTA-derived TPV and NCPV as well as %APV, %PB and the presence of napkin-ring sign and spotty calcification are associated with presence of lesion-specific ischemia. Coronary plaque assessment from CCTA images provide improved discrimination of lesion-specific ischaemia.

Impact of ultra-high-resolution on cardiac CT assessment of coronary artery stenoses, plaque burden/composition, and pericoronary adipose tissue attenuation

Abstract Background Conventional coronary computed tomography angiography (CCTA) overestimates stenoses within stents and calcified arteries due to "blooming" artifacts. Ultra-high-resolution coronary CT (UHR-CT) may overcome this limitation because of higher spatial resolution. Purpose To investigate differences in coronary arterial lumen volume, stenosis severity, and plaque composition, between CCTA and UHRCT in patients with stents and/or high coronary calcium scores. Methods As part of a prospective pilot study, 14 patients referred for invasive coronary angiography for evaluation of obstructive CAD underwent UHRCT (Canon Precision, 160 x 0.25mm slices) prior to catheterization. Images of identical cardiac phases were reconstructed in two badges for comparison: 1) Ultra-high resolution using a 1,024 x 1,024 matrix, 0.25 mm, and 2) conventional resolution with a 524 x 524 matrix, 0.5 mm. All images were reconstructed using iterative reconstruction algorithm (AIDR 3D) and a sharp kernel (FC05). For the left main and three coronary arteries, an automated contour analysis using a dedicated software (QAngioCT RE 3.2, Medis, Netherlands) was performed to compare conventional CCTA vs. UHR-CT resolution images across common vascular and plaque metrics, including lumen and vessel volume, plaque burden/volume, plaque composition based upon predefined fixed intensity cut-off values of CT attenuation, minimal and maximal plaque thickness, pericoronary adipose tissue attenuation (PCAT), minimal lumen area and diameter, and diameter stenosis. All lumen and vessel contours were generated by the software, without manual editing. The segment model proposed by the SCCT was used as reference and the lesions classified as greater than 25% stenosis by visual assessment were recorded. The quality of the images was subjectively assessed using a 5-point Likert scale. Vessel segments with scores 1 (severe artifacts) and 2 (pronounced artifacts) were not included in the analysis. Results The mean patient age was 68.5 years (±6.8), 2 were female (14.3%), 6 patients had stents (11 stented segments) and the mean Agatston score was 947.6 (±449) among the 8 non-stented patients. A total of 56 vessels, 133 segments, and 57 lesions were analyzed. Eight segments (6%) were excluded from the analysis due to poor quality. Results on a per segment and per lesion basis were summarized in the table. The mean PCAT value was significantly lower for the UHRCT images compared to NR reconstruction in both segment (p<0.001) and lesion based (p=0.002) analyses. Plaque differentiation varied by UHRCT resulted in a lower fibrous plaque volumes but higher necrotic (low attenuation) plaque volumes. Conclusions Ultra-high-resolution CT image analysis results in significantly different coronary artery plaque volume and PCAT assessment vs. conventional resolution CCTA. These findings have implications for evaluating high-risk plaque features and perivascular inflammation in patients.Table 1

Prospective deep learning-based quantitative assessment of coronary plaque by computed tomography angiography compared with intravascular ultrasound: the REVEALPLAQUE study.

Coronary computed tomography angiography provides non-invasive assessment of coronary stenosis severity and flow impairment. Automated artificial intelligence (AI) analysis may assist in precise quantification and characterization of coronary atherosclerosis, enabling patient-specific risk determination and management strategies. This multicentre international study compared an automated deep learning-based method for segmenting coronary atherosclerosis in coronary computed tomography angiography (CCTA) against the reference standard of intravascular ultrasound (IVUS). The study included clinically stable patients with known coronary artery disease from 15 centres in the USA and Japan. An AI-enabled plaque analysis was utilized to quantify and characterize total plaque (TPV), vessel, lumen, calcified plaque (CP), non-calcified plaque (NCP), and low-attenuation plaque (LAP) volumes derived from CCTA and compared with IVUS measurements in a blinded, core laboratory-adjudicated fashion. In 237 patients, 432 lesions were assessed; mean lesion length was 24.5 mm, and mean IVUS-TPV was 186.0 mm3. AI-enabled plaque analysis on CCTA showed strong correlation and high accuracy when compared with IVUS; correlation coefficient, slope, and Y intercept for TPV were 0.91, 0.99, and 1.87, respectively; for CP volume 0.91, 1.05, and 5.32, respectively; and for NCP volume 0.87, 0.98, and 15.24, respectively. Bland-Altman analysis demonstrated strong agreement with little bias for these measurements. AI-enabled CCTA quantification and characterization of atherosclerosis demonstrated strong agreement with IVUS reference standard measurements. This tool may prove effective for accurate evaluation of coronary atherosclerotic burden and cardiovascular risk assessment.

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).

Reproducibility of artificial intelligence-enabled plaque measurements between systolic and diastolic phases from coronary computed tomography angiography.

Current coronary CT angiography (CTA) guidelines suggest both end-systolic and mid-diastolic phases of the cardiac cycle can be used for CTA image acquisition. However, whether differences in the phase of the cardiac cycle influence coronary plaque measurements is not known. We aim to explore the potential impact of cardiac phases on quantitative plaque assessment. We enrolled 39 consecutive patients (23 male, age 66.2 ± 11.5 years) who underwent CTA with dual-source CT with visually evident coronary atherosclerosis and with good image quality. End-systolic and mid- to late-diastolic phase images were reconstructed from the same CTA scan. Quantitative plaque and stenosis were analyzed in both systolic and diastolic images using artificial intelligence (AI)-enabled plaque analysis software (Autoplaque). Overall, 186 lesions from 39 patients were analyzed. There were excellent agreement and correlation between systolic and diastolic images for all plaque volume measurements (Lin's concordance coefficient ranging from 0.97 to 0.99; R ranging from 0.96 to 0.98). There were no substantial intrascan differences per patient between systolic and diastolic phases (p > 0.05 for all) for total (1017.1 ± 712.9 mm3 vs. 1014.7 ± 696.2 mm3), non-calcified (861.5 ± 553.7 mm3 vs. 856.5 ± 528.7 mm3), calcified (155.7 ± 229.3 mm3 vs. 158.2 ± 232.4 mm3), and low-density non-calcified plaque volume (151.4 ± 106.1 mm3 vs. 151.5 ± 101.5 mm3) and diameter stenosis (42.5 ± 18.4% vs 41.3 ± 15.1%). Excellentagreement and no substantial differences were observed in AI-enabled quantitative plaque measurements on CTA in systolic and diastolic images. Following further validation, standardized plaque measurements can be performed from CTA in systolic or diastolic cardiac phase. Quantitative plaque assessment using artificial intelligence-enabled plaque analysis software can provide standardized plaque quantification, regardless of cardiac phase. • The impact of different cardiac phases on coronary plaque measurements is unknown. • Plaque analysis using artificial intelligence-enabled software on systolic and diastolic CT angiography images shows excellent agreement. • Quantitative coronary artery plaque assessment can be performed regardless of cardiac phase.

2024 Consensus Statement on Coronary Stenosis and Plaque Evaluation in CT Angiography From the Asian Society of Cardiovascular Imaging-Practical Tutorial (ASCI-PT).

The Asian Society of Cardiovascular Imaging-Practical Tutorial (ASCI-PT) is an instructional initiative of the ASCI School designed to enhance educational standards. In 2021, the ASCI-PT was convened with the goal of formulating a consensus statement on the assessment of coronary stenosis and coronary plaque using coronary CT angiography (CCTA). Nineteen experts from four countries conducted thorough reviews of current guidelines and deliberated on eight key issues to refine the process and improve the clarity of reporting CCTA findings. The experts engaged in both online and on-site sessions to establish a unified agreement. This document presents a summary of the ASCI-PT 2021 deliberations and offers a comprehensive consensus statement on the evaluation of coronary stenosis and coronary plaque in CCTA.

Abstract 14972: Association Between CEC Measured by Immobilized Liposome-Bound Gel Beads Method and the Size of Lipid-Rich Coronary Artery Plaque

Introduction/Background: High-density lipoprotein (HDL) exerts cholesterol efflux capacity (CEC), and it ameliorates cardiovascular disease (CVD). CEC had been expected as a surrogate biomarker in addition to HDL cholesterol (HDL-C), which has been found not always to reflect the CVD risk. However, the procedures of the conventional CEC assays were too complex to be introduced into clinical practice because of cell-based assay. Given this situation, we invented novel cell-free CEC assay named immobilized liposome-bound gel beads (ILG) method. ILG method utilizes liposomes which contain fluorescence labeled cholesterol instead of lipid loaded foam cells, and has advantage of simplicity of procedure and accuracy. Reserch Question/Hypothesis: Does ILG method show some associations between CEC and HDL subclass, and also reflect the condition of coronary artery plaque? Goals/Aim: We aim to demonstrate CEC by ILG method has clinical significance for assessment of the CVD risk. Methods/Approach: Patients who underwent diagnostic catheterization or percutaneous coronary intervention were enrolled, and 61 patients were examined through CEC analysis by ILG method and assessment of coronary artery plaque by optical coherence tomography (OCT) imaging. Large lipid-rich plaque was defined as a lipid plaque with a lipid arc ≥180°and lipid length ≥5 mm. Serum HDL subclass was analyzed by enzymatic assay (Denka). We defined the ratio apolipoprotein E(apoE)-containing HDL-C to HDL-C as %apoE, and we also calculated the value of HDL 3 -C/HDL 2 -C, and classified HDL 3 - or HDL 2 -rich group. Results/Data: HDL-C was positively associated with %apoE, and CEC of apoE-rich patients was higher than that of apoE-poor patients. This correlation was maintained after classified based on size of HDL. CEC and %apoE in patients with large lipid-rich plaque were significantly lower than in those in without. In contrast, there was no significant difference in HDL-C and LDL-C. Conclusion: In present study, ILG method showed that apoE has some influence on CEC, and CEC was inversely correlated with size of lipid-rich plaque. These results implied that ILG method, suitable CEC assay for clinical site, might be useful to assess the CVD risk.

Abstract 17494: The Incremental Risk Prediction of Cardiac CTA-Derived Quantitative Atherosclerosis in the International Advance Registry

Background: We sought to assess the incremental prognostic utility of AI-enabled quantitative coronary plaque assessment (AI-QCPA) beyond stenosis severity and FFR CT , for the prediction of late revascularization and MACE in the large prospective international ADVANCE registry. Methods: 4737 participants were submitted for AI-QCPA evaluation. Total plaque volume (TPV), calcified plaque volume (CPV), non-calcified plaque volume (NCPV), and low attenuated plaque volume (LAPV) were quantified. In addition, total percent plaque volume (TPAV) and its components were calculated (PV/Vessel Volume * 100). Demographics, stenosis severity, lowest FFR CT , and Delta FFR CT were also recorded. To explore the relationship between plaque measures and MACE (death, myocardial infarction, and unplanned hospitalization leading to revascularization) and late revascularization (>90 days) we performed Kaplan Meier event free outcomes analyses following adjustments for stenosis severity, FFR CT and Delta FFR CT . Results: AI-QCPA was available in 4430 subjects. Mean (SD) TPV was 542.4 ± 522.5 mm 3 . Optimal cutpoints of plaque metrics were predictive of MACE and/or late revascularization when adjusted-TPV (HR- 1.45 CI- 1.06-1.98; P=0.02); CPV (HR- 1.65 CI- 1.21- 2.26; p=0.002); NCPV (HR 1.43 CI- 1.02-1.99; P=0.04) and LAPV (HR- 2.23 CI 1.62-3.07; P=0.03 . Stronger risk prediction was achieved by plaque measures adjusted for vessel volume: TPAV (HR 1.92 CI 1.40- 2.64 P<0.001). This incremental risk discrimination of quantitative plaque measures remained significant as a predictor of MACE alone- TPV- (HR 1.84 CI 1.02- 3.29 P=0.04) TPAV (HR 3.33 CI- 1.85- 6.02 P<0.0001) (Figure 1). Conclusions: In this large prospective international registry, AI-QCPA provided incremental risk discrimination for MACE and late revascularization beyond stenosis severity and FFR CT .

Prognostic value of plaque volume combined with CT fractional flow reserve in patients with suspected coronary artery disease

To investigate the prognostic value of quantitative plaque volume on coronary computed tomography (CT) angiography (CTA) combined with CT fractional flow reserve (CT-FFR) for major adverse cardiac events (MACE) in suspected coronary artery disease (CAD) patients. Patients who underwent coronary CTA with clinically suspected CAD were enrolled retrospectively in this study. Patients' baseline, Framingham Risk Score (FRS), coronary CTA plaque assessment, and CT-FFR were analysed retrospectively. Study outcomes included rehospitalisation and MACE (ST-segment elevation myocardial infarction, unstable angina, or non-ST-segment elevation myocardial infarction, revascularisation, and cardiac death). There were 251 patients in the study, with a follow-up period of 1-6.58 years. Mean age was 61.16±10.45 years and 146 (58%) patients were male. Higher CT-adapted Leaman score and quantitative plaque volume were found in patients with FRS >0.2 regardless of categorical or continuous variables. Coronary scores, quantitative plaque parameters, and CT-FFR were associated with MACE and rehospitalisation in univariate analysis. In model 1, CT-FFR was associated with MACE in multivariate Cox analysis when adjusted for FRS and CT-adapted Leaman score. Quantitative plaque parameters including calcified plaque volume, fibro-fatty plaque volume, low-attenuation plaque volume, non-calcified plaque volume, and total plaque volume were significantly associated with MACE and improved overall prognostic performance in a model adjusted for CT-FFR. Additional quantitative plaque volume and CT-FFR further improve the predictive incremental value based on risk factor scores for prognostic prediction in patients. Adding quantitative plaque volume combined with CT-FFR analysis to anatomical and clinical assessment will be further beneficial to predict patients' prognosis of MACE.

Changes in coronary plaque component volumes comparing different virtual monoenergetic images using photon-counting computed tomography

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): BV was supported by the ÚNKP-22-3-II-SE New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund. Introduction Photon-counting CT (PCCT) allows virtual monoenergetic images (VMIs) which may aid more precise assessment of coronary plaques. We aimed to analyze how plaque component volumes change on different VMIs. Methods Coronary CT angiography images were acquired using a dual-source PCCT and VMIs were reconstructed between 40–180 keV in 10 keV increments. Polychromatic images at 120 kVp (T3D) were also reconstructed and used as reference. Quantitative image quality analysis was performed on all reconstructed images. Quantitative plaque assessment was performed on T3D images and segmentation masks were copied to all VMI images. Calcified plaque (CP; >350 Hounsfield units, HU), non-calcified plaque (NCP; 30–350HU) and low-attenuation NCP (LAP; −100-30HU) volumes were calculated. Results We analyzed 51 plaques from 51 patients (67% male, mean age 65±12 years). Average attenuation and contrast-to-noise ratio (CNR) decreased significantly with increasing keV levels, with similar values observed between T3D and 70 keV images (299±209 vs 303±225 HU, p = 0.15 for mean HU; 15.5±3.7 vs. 15.8±3.5, p = 0.32 for CNR). Mean NCP volume was comparable between T3D and 100–180 keV reconstructions. There was a graded decrease in mean CP volume, with a significant difference between all VMI images and T3D (p<0.05). LAP volume increased with increasing VMI energy levels and all VMI images showed a significant difference compared to T3D, except for 50 keV (28.0±30.8 mm3 and 28.6±30.1 mm3, respectively, p = 0.63). Conclusion Fixed threshold settings result in significantly different plaque volumes when using VMIs as compared to T3D images. Normalization protocols are needed to have comparable results between future studies.

Clinical quantitative coronary artery stenosis and coronary atherosclerosis imaging: a Consensus Statement from the Quantitative Cardiovascular Imaging Study Group.

The detection and characterization of coronary artery stenosis and atherosclerosis using imaging tools are key for clinical decision-making in patients with known or suspected coronary artery disease. In this regard, imaging-based quantification can be improved by choosing the most appropriate imaging modality for diagnosis, treatment and procedural planning. In this Consensus Statement, we provide clinical consensus recommendations on the optimal use of different imaging techniques in various patient populations and describe the advances in imaging technology. Clinical consensus recommendations on the appropriateness of each imaging technique for direct coronary artery visualization were derived through a three-step, real-time Delphi process that took place before, during and after the Second International Quantitative Cardiovascular Imaging Meeting in September 2022. According to the Delphi survey answers, CT is the method of choice to rule out obstructive stenosis in patients with an intermediate pre-test probability of coronary artery disease and enables quantitative assessment of coronary plaque with respect to dimensions, composition, location and related risk of future cardiovascular events, whereas MRI facilitates the visualization of coronary plaque and can be used in experienced centres as a radiation-free, second-line option for non-invasive coronary angiography. PET has the greatest potential for quantifying inflammation in coronary plaque but SPECT currently has a limited role in clinical coronary artery stenosis and atherosclerosis imaging. Invasive coronary angiography is the reference standard for stenosis assessment but cannot characterize coronary plaques. Finally, intravascular ultrasonography and optical coherence tomography are the most important invasive imaging modalities for the identification of plaques at high risk of rupture. The recommendations made in this Consensus Statement will help clinicians to choose the most appropriate imaging modality on the basis of the specific clinical scenario, individual patient characteristics and the availability of each imaging modality.

Endothelial shear stress computed from coronary computed tomography angiography: A direct comparison to intravascular ultrasound

IntroductionIntravascular ultrasound (IVUS) studies have shown that biomechanical variables, particularly endothelial shear stress (ESS), add synergistic prognostic insight when combined with anatomic high-risk plaque features. Non-invasive risk assessment of coronary plaques with coronary computed tomography angiography (CCTA) would be helpful to enable broad population risk-screening. AimTo compare the accuracy of ESS computation of local ESS metrics by CCTA vs IVUS imaging. MethodsWe analyzed 59 patients from a registry of patients who underwent both IVUS and CCTA for suspected CAD. CCTA images were acquired using either a 64- or 256-slice scanner. Lumen, vessel, and plaque areas were segmented from both IVUS and CCTA (59 arteries, 686 3-mm segments). Images were co-registered and used to generate a 3-D arterial reconstruction, and local ESS distribution was assessed by computational fluid dynamics (CFD) and reported in consecutive 3-mm segments. ResultsAnatomical plaque characteristics (vessel, lumen, plaque area and minimal luminal area [MLA] per artery) were correlated when measured with IVUS and CCTA: 12.7 ​± ​4.3 vs 10.7 ​± ​4.5 ​mm2, r ​= ​0.63; 6.8 ​± ​2.7 vs 5.6 ​± ​2.7 ​mm2, r ​= ​0.43; 5.9 ​± ​2.9 vs 5.1 ​± ​3.2 ​mm2, r ​= ​0.52; 4.5 ​± ​1.3 vs 4.1 ​± ​1.5 ​mm2, r ​= ​0.67 respectively. ESS metrics of local minimal, maximal, and average ESS were also moderately correlated when measured with IVUS and CCTA (2.0 ​± ​1.4 vs 2.5 ​± ​2.6 ​Pa, r ​= ​0.28; 3.3 ​± ​1.6 vs 4.2 ​± ​3.6 ​Pa, r ​= ​0.42; 2.6 ​± ​1.5 vs 3.3 ​± ​3.0 ​Pa, r ​= ​0.35, respectively). CCTA-based computation accurately identified the spatial localization of local ESS heterogeneity compared to IVUS, with Bland-Altman analyses indicating that the absolute ESS differences between the two CCTA methods were pathobiologically minor. ConclusionLocal ESS evaluation by CCTA is possible and similar to IVUS; and is useful for identifying local flow patterns that are relevant to plaque development, progression, and destabilization.

Does Coronary Plaque Morphology Matter Beyond Plaque Burden?

Imaging of adverse coronary plaque features by coronary computed tomography angiography (CCTA) has advanced greatly and at a fast pace. We aim to describe the evolution, present and future in plaque analysis, and its value in comparison to plaque burden. Recently, it has been demonstrated that in addition to plaque burden, quantitative and qualitative assessment of coronary plaque by CCTA can improve the prediction of future major adverse cardiovascular events in diverse coronary artery disease scenarios. The detection of high-risk non-obstructive coronary plaque can lead to higher use of preventive medical therapies such as statins and aspirin, help identify culprit plaque, and differentiate between myocardial infarction types. Even more, over traditional plaque burden, plaque analysis including pericoronary inflammation can potentially be useful tools for tracking disease progression and response to medical therapy. The identification of the higher risk phenotypes with plaque burden, plaque characteristics, or ideally both can allow the allocation of targeted therapies and potentially monitor response. Further observational data are now required to investigate these key issues in diverse populations, followed by rigorous randomized controlled trials.

Current Applications and New Perspectives in Optical Coherence Tomography (OCT) Coronary Atherosclerotic Plaque Assessment: From PCI Optimization to Pharmacological Treatment Guidance

Since its ability to precisely characterized atherosclerotic plaque phenotypes, to tailor stent implantation, as well as to guide both complex percutaneous coronary interventions (PCI) and invasive diagnostic work-ups (e.g., spontaneous coronary dissections or myocardial infarction with non-obstructive arteries), the adoption of optical coherence tomography (OCT) was raised in the past decades in order to provide complementary information to the traditional angiography and to overcome its limitations. However, the impact of OCT on daily clinical practice is currently modest, firstly because of the lack of both standardized algorithms of PCI guidance and data from prospective clinical trials. Therefore, the aim of our narrative review is to provide a comprehensive overview of the basic OCT interpretation, to summarize the evidence supporting the OCT guidance procedures and applications, to discuss its current limitations, and to highlight the knowledge gaps that need to be filled with more robust evidence.

Anatomical validation of automatic respiratory motion correction for coronary 18F-sodium fluoride positron emission tomography by expert measurements from four-dimensional computed tomography.

Respiratory motion correction is of importance in studies of coronary plaques employing 18 F-NaF; however, the validation of motion correction techniques mainly relies on indirect measures such as test-retest repeatability assessments. In this study, we aim to compare and, thus, validate the respiratory motion vector fields obtained from the positron emission tomography (PET) images directly to the respiratory motion observed during four-dimensional cine-computed tomography (CT) by an expert observer. To investigate the accuracy of the motion correction employed in a software (FusionQuant) used for evaluation of 18 F-NaF PET studies by comparing the respiratory motion of the coronary plaques observed in PET to the respiratory motion observed in 4D cine-CT images. This study included 23 patients who undertook thoracic PET scans for the assessment of coronary plaques using 18 F-sodium fluoride (18 F-NaF). All patients underwent a 5-s cine-CT (4D-CT), a coronary CT angiography (CTA), and 18 F-NaF PET. The 4D-CT and PET scan were reconstructed into 10 phases. Respiratory motion was estimated for the non-contrast visible coronary plaques using diffeomorphic registrations (PET) and compared to respiratory motion observed on 4D-CT. We report the PET motion vector fields obtained in the three principal axes in addition to the 3D motion. Statistical differences were examined using paired t-tests. Signal-to-noise ratios (SNR) are reported for the single-phase images (end-expiratory phase) and for the motion-corrected image-series (employing the motion vector fields extracted during the diffeomorphic registrations). In total, 19 coronary plaques were identified in 16 patients. No statistical differences were observed for the maximum respiratory motion observed in x, y, and the 3D motion fields (magnitude and direction) between the CT and PET (X direction: 4D CT=2.5±1.5mm, PET=2.4±3.2mm; Y direction: 4D CT=2.3±1.9mm, PET=0.7±2.9mm, 3D motion: 4D CT=6.6±3.1mm, PET=5.7±2.6mm, all p≥0.05). Significant differences in respiratory motion were observed in the systems' Z direction: 4D CT=4.9±3.4mm, PET=2.3±3.2mm, p=0.04. Significantly improved SNR is reported for the motion corrected images compared to the end-expiratory phase images (end-expiratory phase=6.8±4.8, motion corrected=12.2±4.5, p=0.001). Similar respiratory motion was observed in two directions and 3D for coronary plaques on 4D CT as detected by automatic respiratory motion correction of coronary PET using FusionQuant. The respiratory motion correction technique significantly improved the SNR in the images.

Non-Invasive Modalities in the Assessment of Vulnerable Coronary Atherosclerotic Plaques.

Coronary atherosclerosis is a complex, multistep process that may lead to critical complications upon progression, revolving around plaque disruption through either rupture or erosion. Several high-risk features are associated with plaque vulnerability and may add incremental prognostic information. Although invasive imaging modalities such as optical coherence tomography or intravascular ultrasound are considered to be the gold standard in the assessment of vulnerable coronary atherosclerotic plaques (VCAPs), contemporary evidence suggests a potential role for non-invasive methods in this context. Biomarkers associated with deleterious pathophysiologic pathways, including inflammation and extracellular matrix degradation, have been correlated with VCAP characteristics and adverse prognosis. However, coronary computed tomography (CT) angiography has been the most extensively investigated technique, significantly correlating with invasive method-derived VCAP features. The estimation of perivascular fat attenuation as well as radiomic-based approaches represent additional concepts that may add incremental information. Cardiac magnetic resonance imaging (MRI) has also been evaluated in clinical studies, with promising results through the various image sequences that have been tested. As far as nuclear cardiology is concerned, the implementation of positron emission tomography in the VCAP assessment currently faces several limitations with the myocardial uptake of the radiotracer in cases of fluorodeoxyglucose use, as well as with motion correction. Moreover, the search for the ideal radiotracer and the most adequate combination (CT or MRI) is still ongoing. With a look to the future, the possible combination of imaging and circulating inflammatory and extracellular matrix degradation biomarkers in diagnostic and prognostic algorithms may represent the essential next step for the assessment of high-risk individuals.

466 Coronary Artery Plaque Assessment In Inflammatory Bowel Disease

Introduction: Inflammatory bowel diseases (IBD), ulcerative colitis (UC) and Crohn’s disease (CD), are associated with increased risk for atherosclerotic cardiovascular disease (ASCVD). The nature of coronary plaque by CT angiogram (CTA) can predict future ASCVD event. No prior study has assessed CTA in IBD. We aimed to characterize coronary plaque and ASCVD risk in IBD patients by CTA.

Longitudinal Quantitative Assessment of Coronary Atherosclerotic Plaque Burden Related to Serum Hemoglobin Levels

Despite a potential role of hemoglobin in atherosclerosis, data on coronary plaque volume changes (PVC) related to serum hemoglobin levels are limited. The authors sought to evaluate coronary atherosclerotic plaque burden changes related to serum hemoglobin levels using serial coronary computed tomographic angiography (CCTA). A total of 830 subjects (age 61 ± 10 years, 51.9% male) who underwent serial CCTA were analyzed. The median interscan period was 3.2 (IQR: 2.5-4.4) years. Quantitative assessment of coronary plaques was performed at both scans. All participants were stratified into 4 groups based on the quartile of baseline hemoglobin levels. Annualized total PVC (mm3/year) was defined as total PVC divided by the interscan period. Baseline total plaque volume (mm3) was not different among all groups (group I [lowest]: 34.1 [IQR: 0.0-127.4] vs group II: 28.8 [IQR: 0.0-123.0] vs group III: 49.9 [IQR: 5.6-135.0] vs group IV [highest]: 34.3 [IQR: 0.0-130.7]; P=0.235). During follow-up, serum hemoglobin level changes (Δ hemoglobin; per 1 g/dL) was related to annualized total PVC (β =-0.114) in overall participants (P< 0.05). After adjusting for age, sex, traditional risk factors, baseline hemoglobin and creatinine levels, baseline total plaque volume, and the use of aspirin, beta-blocker, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker, and statin, Δ hemoglobin significantly affected annualized total PVC in only the composite of groups I and II (β =-2.401; P=0.004). Serial CCTA findings suggest that Δ hemoglobin has an independent effect on coronary atherosclerosis. This effect might be influenced by baseline hemoglobin levels. (Progression of Atherosclerotic Plaque Determined by Computed Tomographic Angiography Imaging [PARADIGM]; NCT02803411).

Prognostic value of epicardial adipose tissue volume in combination with coronary plaque and flow assessment for the prediction of major adverse cardiac events

PurposeThe purpose of this study was to determine whether EAT volume in combination with coronary CT angiography (CCTA)-derived plaque quantification and CT-derived fractional flow reserve (CT-FFR) has prognostic implication with major adverse cardiac events (MACE). MethodsPatients (n = 117, 58 ± 10 years, 61% male) who had previously undergone invasive coronary angiography (ICA) and CCTA were retrospectively analyzed. Follow-up was performed to record MACE. EAT volume and plaque measures were derived from non-contrast and contrast-enhanced CT images using a semi-automatic software approach, while CT-FFR was calculated using a machine-learning algorithm. The diagnostic performance to identify MACE was evaluated using univariable and multivariable Cox proportional hazards analysis and concordance (C)-indices. ResultsDuring a median follow-up period of 40.4 months, 19 events were registered. EAT volume, CCTA ≥ 50% stenosis, and CT-FFR were significantly different in patients developing MACE (all p < 0.05). The following parameters were predictors of MACE in adjusted multivariable Cox regression analysis (hazard ratio [HR]): EAT volume (HR 2.21, p = 0.023), indexed EAT volume (HR 2.03, p = 0.035), and CCTA ≥ 50% (HR 1.05, p = 0.048). A model including Morise score, CCTA ≥ 50% stenosis, and EAT volume showed significantly improved C-index to Morise score alone (AUC 0.83 vs. 0.66, p = 0.004). ConclusionsFacing limitations in conventional cardiovascular risk scoring models, this observational study demonstrates that the prediction performance of our proposed method achieves a significant improvement in prognostic ability, especially when compared to models such as Morise score alone or its combination with CCTA and CT-FFR.

Abstract 13620: Comparison of Endothelial Shear Stress (ESS) Computation Utilizing Non-Invasive Coronary Computed Tomography Angiography (CCTA) vs Invasive Intravascular Ultrasound (IVUS) Imaging

Introduction: Risk-stratification of individual coronary plaques is an important goal to detect high-risk plaques likely to progress/destabilize, which could inform preemptive intervention to prevent adverse cardiac events. IVUS imaging, the current gold standard to assess plaque risk, has shown that biomechanical variables, particularly local ESS, contributes critical synergistic prognostic insight when combined with anatomic high-risk plaque features. Non-invasive risk assessment of coronary plaques with CCTA would be invaluable to enable broad population risk screening, but it is unknown whether CCTA, which has less spatial resolution than IVUS, can adequately measure the critical local biomechanical and anatomic variables. Aim: To compare the accuracy of ESS computation of local ESS metrics by non-invasive CCTA vs invasive IVUS imaging. Methods: We analyzed 30 arteries (22 LAD, 4 LCx,4 RCA) from 30 patients selected from a registry of patients who underwent both IVUS and CCTA of the same artery for suspected CAD. CCTA images were acquired using a CCTA with either 64 or 256 detector rows. We segmented lumen, vessel, and plaque areas with both IVUS (manual segmentation) and CCTA (AI based software; Cleerly Inc, NY). Co-registration of IVUS and CCTA Images was performed using fiduciary anatomic landmarks. Images from IVUS and CCTA were used to generate a 3-D arterial reconstruction, and local ESS distribution was assessed by computational fluid dynamics and reported in consecutive 3-mm segments. Results: Table Conclusion: Compared to IVUS values, 256-slice is more accurate than 64-slice CCTA to measure lumen and vessel areas, but computation of detailed local ESS (average, low and high) is similar by both CCTA methods. Local ESS evaluation using non-invasive CCTA is feasible and comparable to invasive gold standard IVUS and is suitable to characterize the local flow patterns that play an important role in plaque development, progression, and destabilization