Radiomics Analysis of Pericoronary Adipose Tissue From Baseline Coronary Computed Tomography Angiography Enables Prediction of Coronary Plaque Progression

PURPOSE

The relationship between plaque progression and pericoronary adipose tissue (PCAT) radiomics has not been comprehensively evaluated. We aim to predict plaque progression with PCAT radiomics features and evaluate their incremental value over quantitative plaque characteristics.

PATIENTS AND METHODS

Between January 2009 and December 2020, 500 patients with suspected or known coronary artery disease who underwent serial coronary computed tomography angiography (CCTA) ≥2 years apart were retrospectively analyzed and randomly stratified into a training and testing data set with a ratio of 7:3. Plaque progression was defined with annual change in plaque burden exceeding the median value in the entire cohort. Quantitative plaque characteristics and PCAT radiomics features were extracted from baseline CCTA. Then we built 3 models including quantitative plaque characteristics (model 1), PCAT radiomics features (model 2), and the combined model (model 3) to compare the prediction performance evaluated by area under the curve.

RESULTS

The quantitative plaque characteristics of the training set showed the values of noncalcified plaque volume (NCPV), fibrous plaque volume, lesion length, and PCAT attenuation were larger in the plaque progression group than in the nonprogression group ( P < 0.05 for all). In multivariable logistic analysis, NCPV and PCAT attenuation were independent predictors of coronary plaque progression. PCAT radiomics exhibited significantly superior prediction over quantitative plaque characteristics both in the training (area under the curve: 0.814 vs 0.615, P < 0.001) and testing (0.736 vs 0.594, P = 0.007) data sets.

CONCLUSIONS

NCPV and PCAT attenuation were independent predictors of coronary plaque progression. PCAT radiomics derived from baseline CCTA achieved significantly better prediction than quantitative plaque characteristics.

Relationship between peri-coronary inflammation and coronary vascular function in patients with suspected coronary artery disease

Background

In this study, we aim to investigate the relationship between the attenuation of peri-coronary adipose tissue (PCAT) in patients with suspected coronary artery disease (CAD) and the assessment of coronary vascular functions using coronary flow reserve (CFR).

Methods

We included 364 patients who underwent 13N-NH3 positron emission tomography/computed tomography and coronary computed tomography angiography (CCTA). We determined the relationship between fat attenuation index (FAI), PCAT volume, and other qualitative CT-derived anatomic parameters with CFR.

Results

We detected a decrease in CFR (<2.5) in 206 (57%) patients. At the patient level, those with reduced CFR showed a significantly higher prevalence of diffused atherosclerosis (41% vs. 23%; P < 0.001) and higher FAI (-75.5 HU vs. -77.1 HU; P = 0.014). In patients without obstructive CAD, FAI was significantly higher in those with reduced CFR (-75.5 HU vs. -77.7 HU, P = 0.026). On the vessel level, 1,092 vessels were analyzed, and 642 (59%) exhibited reduced CFR. The vessels with reduced CFR presented a significantly higher prevalence of obstructive CAD (37% vs. 26%; P < 0.001), diffused atherosclerosis (22% vs. 11%; P < 0.001), low-attenuation plaque (6% vs. 3%; P = 0.030), and positive remodeling (7% vs. 2%; P = 0.001). FAI was higher in vessels with reduced CFR (-80.8 HU vs. -81.8 HU; P = 0.045) than in normal CFR. In the patient-level analysis, obstructive CAD, diffused atherosclerosis, and FAI were independently linked with CFR. FAI was still associated with global CFR after adjusting for traditional risk factors (age, hypertension, diabetes, hyperlipidemia, and smoking). FAI remained independently associated with reduced CFR in patients without obstructive CAD.

Conclusions

Coronary perivascular inflammation evaluated by CCTA was independently associated with coronary vascular function. In patients without obstructive CAD, FAI was higher in the presence of reduced CFR. Altogether, FAI can help reveal microcirculatory damage in patients who do not exhibit epicardial artery stenosis.

Lesion-specific pericoronary adipose tissue CT attenuation improves risk prediction of major adverse cardiovascular events in coronary artery disease

OBJECTIVES

To determine whether lesion-specific pericoronary adipose tissue CT attenuation (PCATa) is superior to PCATa around the proximal right coronary artery (PCATa-RCA) and left anterior descending artery (PCATa-LAD) for major adverse cardiovascular events (MACE) prediction in coronary artery disease (CAD).

METHODS

Six hundred and eight CAD patients who underwent coronary CTA from January 2014 to December 2018 were retrospectively included, with clinical risk factors, plaque features, lesion-specific PCATa, PCATa-RCA, and PCATa-LAD collected. MACE was defined as cardiovascular death, non-fatal myocardial infarction, unplanned revascularization, and hospitalization for unstable angina. Four models were established, encapsulating traditional factors (Model A), traditional factors and PCATa-RCA (Model B), traditional factors and PCATa-LAD (Model C), and traditional factors and lesion-specific PCATa (Model D). Prognostic performance was evaluated with C-statistic, area under receiver operator characteristic curve (AUC), and net reclassification index (NRI).

RESULTS

Lesion-specific PCATa was an independent predictor for MACE (adjusted hazard ratio = 1.108, P < .001). The C-statistic increased from 0.750 for model A to 0.762 for model B (P = .078), 0.773 for model C (P = .046), and 0.791 for model D (P = .005). The AUC increased from 0.770 for model A to 0.793 for model B (P = .027), 0.793 for model C (P = .387), and 0.820 for model D (P = .019). Compared with model A, the NRIs for models B, C, and D were 0.243 (-0.323 to 0.792, P = .392), 0.428 (-0.012 to 0.835, P = .048), and 0.708 (0.152-1.016, P = .001), respectively.

CONCLUSIONS

Lesion-specific PCATa improves risk prediction of MACE in CAD, which is better than PCATa-RCA and PCATa-LAD.

ADVANCES IN KNOWLEDGE

Lesion-specific PCATa was superior to PCATa-RCA and PCATa-LAD for MACE prediction.

Hybrid model of CT-fractional flow reserve, pericoronary fat attenuation index and radiomics for predicting the progression of WMH: a dual-center pilot study

Objective

To develop and validate a hybrid model incorporating CT-fractional flow reserve (CT-FFR), pericoronary fat attenuation index (pFAI), and radiomics signatures for predicting progression of white matter hyperintensity (WMH).

Methods

A total of 226 patients who received coronary computer tomography angiography (CCTA) and brain magnetic resonance imaging from two hospitals were divided into a training set (n = 116), an internal validation set (n = 30), and an external validation set (n = 80). Patients who experienced progression of WMH were identified from subsequent MRI results. We calculated CT-FFR and pFAI from CCTA images using semi-automated software, and segmented the pericoronary adipose tissue (PCAT) and myocardial ROI. A total of 1,073 features were extracted from each ROI, and were then refined by Elastic Net Regression. Firstly, different machine learning algorithms (Logistic Regression [LR], Support Vector Machine [SVM], Random Forest [RF], k-nearest neighbor [KNN] and eXtreme Gradient Gradient Boosting Machine [XGBoost]) were used to evaluate the effectiveness of radiomics signatures for predicting WMH progression. Then, the optimal machine learning algorithm was used to compare the predictive performance of individual and hybrid models based on independent risk factors of WMH progression. Receiver operating characteristic (ROC) curve analysis, calibration and decision curve analysis were used to evaluate predictive performance and clinical value of the different models.

Results

CT-FFR, pFAI, and radiomics signatures were independent predictors of WMH progression. Based on the machine learning algorithms, the PCAT signatures led to slightly better predictions than the myocardial signatures and showed the highest AUC value in the XGBoost algorithm for predicting WMH progression (AUC: 0.731 [95% CI: 0.603-0.838] vs.0.711 [95% CI: 0.584-0.822]). In addition, pFAI provided better predictions than CT-FFR (AUC: 0.762 [95% CI: 0.651-0.863] vs. 0.682 [95% CI: 0.547-0.799]). A hybrid model that combined CT-FFR, pFAI, and two radiomics signatures provided the best predictions of WMH progression [AUC: 0.893 (95%CI: 0.815-0.956)].

Conclusion

pFAI was more effective than CT-FFR, and PCAT signatures were more effective than myocardial signatures in predicting WMH progression. A hybrid model that combines pFAI, CT-FFR, and two radiomics signatures has potential use for identifying WMH progression.

Factors Influencing Functional Coronary Artery Ischemia: A Gender-Specific Predictive Model

Objective

The objective of this study was to explore factors that impact functional coronary artery ischemia (FCAI) and develop a gender-specific prognostic model that could serve as a benchmark for predicting FCAI in clinical practice.

Methods

A cumulative total of 330 patients were enrolled comprising 634 main and branch coronary, consisting of 179 men (359 coronary arteries) and 151 women (275 coronary arteries). Based on the computed tomography-fractional flow reserve (CT-FFR), the coronary arteries of male and female patients were classified into the non-ischemic group (CT-FFR ≥ 0.80) and the ischemic group (CT-FFR < 0.80). We screened for factors related to the CT-FFR values of the coronary arteries in male and female patients and developed corresponding gender-specific models.

Results

In male patients, the correlation between FCAI and several indicators, including white blood cell (WBC) count, left anterior descending artery (LAD) lesions, pericoronary fat attenuation index (FAI), and the degree of coronary artery stenosis, was found to be statistically significant. A predictive model was developed using these factors, yielding an area under the curve (AUC) value of 0.812, with a P value of < 0.001 and a 95% confidence interval (CI) ranging from 0.767 to 0.857. This model demonstrated superior predictive capability compared to any individual indicators mentioned above. Significant correlations with FCAI were observed in female patients for hemoglobin (Hb), systolic blood pressure (SBP), FAI, and the degree of coronary artery stenosis. The predictive model, derived from these factors, exhibited robust performance with an area under the curve (AUC) value of 0.818, a P value of < 0.001, and a 95% confidence interval (CI) ranging from 0.764 to 0.872.

Conclusion

Gender disparities exist in the factors affecting FCAI, underscoring the need for a gender-specific predictive model to enhance the precision of FCAI prediction.

Coronary Inflammation by Computed Tomography Pericoronary Fat Attenuation and Increased Cytokines in Young Male Anabolic Androgenic Steroid Users

BACKGROUND

Anabolic androgenic steroid (AAS) abuse has been associated with coronary artery disease (CAD). Pericoronary fat attenuation (pFA) is a marker of coronary inflammation, which is key in the atherosclerotic process.

OBJECTIVE

To evaluate pFA and inflammatory profile in AAS users.

METHODS

Twenty strength-trained AAS users (AASU), 20 AAS nonusers (AASNU), and 10 sedentary controls (SC) were evaluated. Coronary inflammation was evaluated by mean pericoronary fat attenuation (mPFA) in the right coronary artery (RCA), left anterior descending coronary artery (LAD), and left circumflex (LCx). Interleukin (IL)-1 (IL-1), IL-6, IL-10, and TNF-alpha were evaluated by optical density (OD) in a spectrophotometer with a 450 nm filter. P<0.05 indicated statistical significance.

RESULTS

AASU had higher mPFA in the RCA (-65.87 [70.51-60.70] vs. -78.07 [83.66-72.87] vs.-78.46 [85.41-71.99] Hounsfield Units (HU), respectively, p<0.001) and mPFA in the LAD (-71.47 [76.40-66.61] vs. -79.32 [84.37-74.59] vs. -82.52 [88.44-75.81] HU, respectively, p=0.006) compared with AASNU and SC. mPFA in the LCx was not different between AASU, AASNU, and SC (-72.41 [77.17-70.37] vs. -80.13 [86.22-72.23] vs. -78.29 [80.63-72.29] HU, respectively, p=0.163). AASU compared with AASNU and SC, had higher IL-1, (0.975 [0.847-1.250] vs. 0.437 [0.311-0.565] vs. 0.530 [0.402-0.780] OD, respectively, p=0.002), IL-6 (1.195 [0.947-1.405] vs. 0.427 [0.377-0.577] vs. 0.605 [0.332-0.950] OD, p=0.005) and IL-10 (1.145 [0.920-1.292] vs. 0.477 [0.382-0.591] vs. 0.340 [0.316-0.560] OD, p<0.001). TNF-α was not different between the AASU, AASNU, and SC groups (0.520 [0.250-0.610] vs. 0.377 [0.261-0.548] vs. 0.350 [0.182-430]), respectively.

CONCLUSION

Compared with ASSNU and controls, AASU have higher mPFA and higher systemic inflammatory cytokines profile suggesting that AAS may induce coronary atherosclerosis through coronary and systemic inflammation.

Coronary computed tomography angiography imaging features combined with computed tomography-fractional flow reserve, pericoronary fat attenuation index, and radiomics for the prediction of myocardial ischemia

BACKGROUND

This study aimed to predict myocardial ischemia (MIS) by constructing models with imaging features, CT-fractional flow reserve (CT-FFR), pericoronary fat attenuation index (pFAI), and radiomics based on coronary computed tomography angiography (CCTA).

METHODS AND RESULTS

This study included 96 patients who underwent CCTA and single photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI). According to SPECT-MPI results, there were 72 vessels with MIS in corresponding supply area and 105 vessels with no-MIS. The conventional model [lesion length (LL), MDS (maximum stenosis diameter × 100% / reference vessel diameter), MAS (maximum stenosis area × 100% / reference vessel area) and CT value], radiomics model (radiomics features), and multi-faceted model (all features) were constructed using support vector machine. Conventional and radiomics models showed similar predictive efficacy [AUC: 0.76, CI 0.62-0.90 vs. 0.74, CI 0.61-0.88; p > 0.05]. Adding pFAI to the conventional model showed better predictive efficacy than adding CT-FFR (AUC: 0.88, CI 0.79-0.97 vs. 0.80, CI 0.68-0.92; p < 0.05). Compared with conventional and radiomics model, the multi-faceted model showed the highest predictive efficacy (AUC: 0.92, CI 0.82-0.98, p < 0.05).

CONCLUSION

pFAI is more effective for predicting MIS than CT-FFR. A multi-faceted model combining imaging features, CT-FFR, pFAI, and radiomics is a potential diagnostic tool for MIS.

Relationship between impaired myocardial blood flow by positron emission tomography and low-attenuation plaque burden and pericoronary adipose tissue attenuation from coronary computed tomography: From the prospective PACIFIC trial

BACKGROUND

Positron emission tomography (PET) is the clinical gold standard for quantifying myocardial blood flow (MBF). Pericoronary adipose tissue (PCAT) attenuation may detect vascular inflammation indirectly. We examined the relationship between MBF by PET and plaque burden and PCAT on coronary CT angiography (CCTA).

METHODS

This post hoc analysis of the PACIFIC trial included 208 patients with suspected coronary artery disease (CAD) who underwent [15O]H2O PET and CCTA. Low-attenuation plaque (LAP, < 30HU), non-calcified plaque (NCP), and PCAT attenuation were measured by CCTA.

RESULTS

In 582 vessels, 211 (36.3%) had impaired per-vessel hyperemic MBF (≤ 2.30 mL/min/g). In multivariable analysis, LAP burden was independently and consistently associated with impaired hyperemic MBF (P = 0.016); over NCP burden (P = 0.997). Addition of LAP burden improved predictive performance for impaired hyperemic MBF from a model with CAD severity and calcified plaque burden (P < 0.001). There was no correlation between PCAT attenuation and hyperemic MBF (r = - 0.11), and PCAT attenuation was not associated with impaired hyperemic MBF in univariable or multivariable analysis of all vessels (P > 0.1).

CONCLUSION

In patients with stable CAD, LAP burden was independently associated with impaired hyperemic MBF and a stronger predictor of impaired hyperemic MBF than NCP burden. There was no association between PCAT attenuation and hyperemic MBF.

Computed tomography and nuclear medicine for the assessment of coronary inflammation: clinical applications and perspectives

There is increasing evidence that in patients with atherosclerotic cardiovascular disease (ASCVD) under optimal medical therapy, a persisting dysregulation of the lipid and glucose metabolism, associated with adipose tissue dysfunction and inflammation, predicts a substantial residual risk of disease progression and cardiovascular events. Despite the inflammatory nature of ASCVD, circulating biomarkers such as high-sensitivity C-reactive protein and interleukins may lack specificity for vascular inflammation. As known, dysfunctional epicardial adipose tissue (EAT) and pericoronary adipose tissue (PCAT) produce pro-inflammatory mediators and promote cellular tissue infiltration triggering further pro-inflammatory mechanisms. The consequent tissue modifications determine the attenuation of PCAT as assessed and measured by coronary computed tomography angiography (CCTA). Recently, relevant studies have demonstrated a correlation between EAT and PCAT and obstructive coronary artery disease, inflammatory plaque status and coronary flow reserve (CFR). In parallel, CFR is well recognized as a marker of coronary vasomotor function that incorporates the haemodynamic effects of epicardial, diffuse and small-vessel disease on myocardial tissue perfusion. An inverse relationship between EAT volume and coronary vascular function and the association of PCAT attenuation and impaired CFR have already been reported. Moreover, many studies demonstrated that 18F-FDG PET is able to detect PCAT inflammation in patients with coronary atherosclerosis. Importantly, the perivascular FAI (fat attenuation index) showed incremental value for the prediction of adverse clinical events beyond traditional risk factors and CCTA indices by providing a quantitative measure of coronary inflammation. As an indicator of increased cardiac mortality, it could guide early targeted primary prevention in a wide spectrum of patients. In this review, we summarize the current evidence regarding the clinical applications and perspectives of EAT and PCAT assessment performed by CCTA and the prognostic information derived by nuclear medicine.

Cardiovascular involvement in Erdheim-Chester diseases is associated with myocardial fibrosis and atrial dysfunction

PURPOSE

Erdheim-Chester disease (ECD) is a rare multisystem histiocytosis, whose cardiovascular involvement has not been systematically characterized so far. We aimed to systematically (qualitatively and quantitatively) describe the features of cardiovascular involvement in a large cohort of ECD patients and to evaluate its impact on myocardial fibrosis extension and cardiac function.

MATERIAL AND METHODS

Among 54 patients with biopsy-proven ECD, 29 patients (59 ± 12 years, 79% males) underwent 1.5-T CMR using a standardized protocol for qualitative and quantitative assessment of disease localization, evaluation of atrial and ventricular function, and assessment of non-dense and dense myocardial fibrosis.

RESULTS

The right atrioventricular (AV) groove was the most commonly affected cardiac site (76%) followed by the right atrial walls (63%), thoracic aorta (59%), and superior vena cava (38%). Right AV groove involvement, encasing the right ventricular artery, was associated with non-dense myocardial fibrosis in the infero-septal (20/26 patients) and the inferior (14/26 patients) mid-basal left ventricular (LV) wall. In two patients with right AV groove localization, LGE revealed myocardial infarction in the same myocardial segments. Three out of five patients with left AV groove involvement had non-dense LGE on the lateral LV mid-basal wall. Bulky right atrial pseudomass was associated with atrial dysfunction and superior and inferior vena cava stenosis.

CONCLUSIONS

In ECD patients, AV groove localization is associated with LV wall fibrosis in the downstream coronary territories, suggesting hemodynamic alterations due to coronary encasement. Conversely, atrial pseudomass ECD localizations impact on atrial contractility causing atrial dysfunction and are associated with atrio-caval junction stenosis.

Pericoronary Adipose Tissue Attenuation in Patients With Acute Coronary Syndrome Versus Stable Coronary Artery Disease

BACKGROUND

Pericoronary adipose tissue (PCAT) attenuation has been associated with coronary inflammation and can be evaluated with coronary computed tomography angiography. The aims of this study were to compare the PCAT attenuation across precursors of culprit and nonculprit lesions of patients with acute coronary syndrome versus stable coronary artery disease (CAD).

METHODS

In this case-control study, patients with suspected CAD who underwent coronary computed tomography angiography were included. Patients who developed an acute coronary syndrome within 2 years after the coronary computed tomography angiography scan were identified, and patients with stable CAD (defined as any coronary plaque ≥30% luminal diameter stenosis) were 1:2 propensity score matched for age, sex, and cardiac risk factors. The mean PCAT attenuation was analyzed at lesion level and compared between precursors of culprit lesions, nonculprit lesions, and stable coronary plaques.

RESULTS

In total, 198 patients (age 62±10 years, 65% male) were selected, including 66 patients who developed an acute coronary syndrome and 132 propensity matched patients with stable CAD. Overall, 765 coronary lesions were analyzed (culprit lesion precursors: n=66; nonculprit lesion precursors: n=207; and stable lesions: n=492). Culprit lesion precursors had larger total plaque volume, fibro-fatty plaque volume, and low-attenuation plaque volume compared to nonculprit and stable lesions. The mean PCAT attenuation was significantly higher across culprit lesion precursors compared to nonculprit and stable lesions (-63.8±9.7 Hounsfield units versus -68.8±10.6 Hounsfield units versus -69.6±10.6 Hounsfield units, respectively; P<0.001), whereas the mean PCAT attenuation around nonculprit and stable lesions was not significantly different (P=0.99).

CONCLUSIONS

The mean PCAT attenuation is significantly increased across culprit lesion precursors in patients with acute coronary syndrome, compared to nonculprit lesions of these patients and to lesions of patients with stable CAD, which may suggest a higher intensity of inflammation. PCAT attenuation on coronary computed tomography angiography may be a novel marker to identify high-risk plaques.

Computed Tomography-derived Characterization of Pericoronary, Epicardial, and Paracardial Adipose Tissue and Its Association With Myocardial Ischemia as Assessed by Computed Fractional Flow Reserve

BACKGROUND

Increased pericoronary adipose tissue (PCAT) attenuation derived from coronary computed tomography (CT) angiography (CTA) relates to coronary inflammation and cardiac mortality. We aimed to investigate the association between CT-derived characterization of different cardiac fat compartments and myocardial ischemia as assessed by computed fractional flow reserve (FFRCT).

METHODS

In all, 133 patients (median 64 y, 74% male) with coronary artery disease (CAD) underwent CTA including FFRCT measurement followed by invasive FFR assessment (FFRINVASIVE). CT attenuation and volume of PCAT were quantified around the proximal right coronary artery (RCA), left anterior descending artery (LAD), and left circumflex artery (LCX). Epicardial adipose tissue (EAT) and paracardial adipose tissue (PAT; all intrathoracic adipose tissue outside the pericardium) were quantified in noncontrast cardiac CT datasets.

RESULTS

Median FFRCT was 0.86 [0.79, 0.91] and median FFRINVASIVE was 0.87 [0.81, 0.93]. Subjects with the presence of myocardial ischemia (n=26) defined by an FFRCT-threshold of ≤0.75 showed significantly higher RCA PCAT attenuation than individuals without myocardial ischemia (n=107) (-75.1±10.8 vs. -81.1±10.6 HU, P=0.011). In multivariable analysis adjusted for age, body mass index, sex and risk factors, increased RCA PCAT attenuation remained a significant predictor of myocardial ischemia. Between individuals with myocardial ischemia compared with individuals without myocardial ischemia, there was no significant difference in the volume and CT attenuation of EAT and PAT or in the PCAT volume of RCA, LAD, and LCX.

CONCLUSIONS

Increased RCA PCAT attenuation is associated with the presence of myocardial ischemia as assessed by FFR, while PCAT volume, EAT, and PAT are not.

Pericoronary fat attenuation index-a new imaging biomarker and its diagnostic and prognostic utility: a systematic review and meta-analysis

Pericoronary fat attenuation index (FAI) on coronary computed tomography angiography imaging has been proposed as a novel marker of coronary vascular inflammation with prognostic value for major cardiovascular events. To date, there is no systematic review of the published literature and no meta-analysed data of previously published results. We performed a systematic review and meta-analysis according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. We systematically explored published literature in MEDLINE (PubMed) before 20 January 2022 for studies assessing FAI in both diagnostic and prognostic clinical settings in patients with or without cardiovascular disease. The primary outcome was the mean difference in FAI attenuation between stable and unstable coronary plaques. The secondary outcome was the hazard ratio (HR) of high FAI values for future cardiovascular events. We calculated I2 to test heterogeneity. We used random-effects modelling for the meta-analyses to assess the primary and secondary outcomes. This study is registered with PROSPERO (CRD42021229491). In total, 20 studies referred in a total of 7797 patients were included in this systematic review, while nine studies were used for the meta-analysis. FAI was significantly higher in unstable compared with stable plaques with a mean difference of 4.50 Hounsfield units [95% confidence interval (CI): 1.10-7.89, I2 = 88%] among 902 patients. Higher pericoronary FAI values offered incremental prognostic value for major adverse cardiovascular events (MACEs) in studies with prospective follow-up (HR = 3.29, 95% CI: 1.88-5.76, I2 = 75%) among 6335 patients. Pericoronary FAI seems to be a promising imaging biomarker that can be used for the detection of coronary inflammation, possibly to discriminate between stable and unstable plaques, and inform on the prognosis for future MACE. Further validation of these findings and exploration of the cost-effectiveness of the method before implementation in clinical practice are needed.

High pericoronary adipose tissue attenuation on computed tomography angiography predicts cardiovascular events in patients with type 2 diabetes mellitus: post-hoc analysis from a prospective cohort study

Background

Pericoronary adipose tissue (PCAT) attenuation on coronary computed tomography angiography (CTA) is a non-invasive biomarker for pericoronary inflammation. We aimed to investigate the prognostic value of PCAT attenuation in patients with type 2 diabetes mellitus (T2DM).

Methods

We included 333 T2DM patients (mean age, 66 years; male patients, 211; mean body mass index, 25 kg/m²) who underwent clinically indicated coronary CTA and examined their CT findings, coronary artery calcium score, pericardial fat volume, stenosis (> 50% luminal narrowing), high-risk plaque features of low-attenuation plaque and/or positive remodelling and/or spotty calcification, and PCAT attenuation. We assessed PCAT attenuation in Hounsfield units (HU) of proximal 40-mm segments of the left anterior descending artery (LAD) and right coronary artery (RCA). Cardiovascular events were defined as cardiac death, hospitalisation for acute coronary syndrome, late coronary revascularisation, and hospitalisation for heart failure.

Results

During a median follow-up of 4.0 years, we observed 31 cardiovascular events. LAD-PCAT attenuation was significantly higher in patients with cardiovascular events than in those without (− 68.5 ± 6.5 HU vs − 70.8 ± 6.1 HU, p = 0.045), whereas RCA-PCAT attenuation was not (p = 0.089). High LAD-PCAT attenuation (> − 70.7 HU; median value) was significantly associated with cardiovascular events in a model that included adverse CTA findings, such as significant stenosis and/or high-risk plaque (hazard ratio; 2.69, 95% confidence interval; 1.17–0.20, p = 0.020). After adding LAD-PCAT attenuation to the adverse CTA findings, the C-statistic and global chi-square values increased significantly from 0.65 to 0.70 (p = 0.037) and 10.9–15.0 (p = 0.043), respectively.

Conclusions

In T2DM patients undergoing clinically indicated coronary CTA, high LAD-PCAT attenuation could significantly predict cardiovascular events. This suggests that assessing LAD-PCAT attenuation can help physicians identify high-risk T2DM patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01478-9.

Influence of Different Segmentations on the Diagnostic Performance of Pericoronary Adipose Tissue

Objective

To investigate the influence of different segmentations on the diagnostic performance of pericoronary adipose tissue (PCAT) CT attenuation and radiomics features for the prediction of ischemic coronary artery stenosis.

Methods

From June 2016 to December 2018, 108 patients with 135 vessels were retrospectively analyzed in the present study. Vessel-based PCAT was segmented along the 40 mm-long proximal segments of three major epicardial coronary arteries, while lesion-based PCAT was defined around coronary lesions. CT attenuation and radiomics features derived from two segmentations were calculated and extracted. The diagnostic performance of PCAT CT attenuation or radiomics models in predicting ischemic coronary stenosis were also compared between vessel-based and lesion-based segmentations.

Results

The mean PCAT CT attenuation was −75.7 ± 9.1 HU and −76.1 ± 8.1 HU (p = 0.395) for lesion-based and vessel-based segmentations, respectively. A strong correlation was found between vessel-based and lesion-based PCAT CT attenuation for all cohort and subgroup analyses (all p < 0.01). A good agreement for all cohort and subgroup analyses was also detected between two segmentations. The diagnostic performance was comparable between vessel-based and lesion based PCAT CT attenuation in predicting ischemic stenosis. The radiomics features of PCAT based on vessel or lesion segmentation can both adequately identify the ischemic stenosis. However, no significant difference was detected between the two segmentations.

Conclusions

The quantitative evaluation of PCAT can be reliably measured both from vessel-based and lesion-based segmentation. Furthermore, the radiomics analysis of PCAT may potentially help predict hemodynamically significant coronary artery stenosis.

Epicardial and periaortic fat characteristics in ischemic stroke: Relationship with stroke etiology and calcification burden

PURPOSE

We explored epicardial (EAT) and periaortic (PAT) adipose tissue characteristics in patients with acute ischemic stroke (AIS), and the relationship with stroke etiology, calcification burden, and inflammation.

METHOD

We included a retrospective cohort of consecutive patients admitted with AIS between 2015 and 2020 who underwent a chest computed tomography. We calculated volumes and attenuation of EAT and PAT, and coronary artery (CAC), and thoracic aortic (TAC) calcification. Admission's neutrophil/lymphocyte ratio (NLR) was recorded. Stroke severity was assessed using the National Institute of Health Stroke Scale (NIHSS), and patients were discriminated between cardioembolic (CE), non-CE, and embolic strokes of uncertain source (ESUS).

RESULTS

A total of 182 patients were included. EAT (non-CE 127.4 ± 47.1 cm3; CE 133.3 ± 56.7 cm3; ESUS 121.6 ± 63.5 cm3, p > 0.05) and PAT (non-CE 37.4 ± 18.6 cm3; CE 40.4 ± 17.2 cm3; ESUS 34.5 ± 14.1 cm3, p > 0.05) volumes were similar between stroke etiologies. Patients with CE stroke had higher PAT attenuation (PAT = non-CE -84.4 ± 7.0 HU; CE -78.1 ± 9.9 HU; ESUS -82.3 ± 9.3 HU, p < 0.001). Using multiple linear regression, albeit weak, we found a significant relationship between NLR and PAT attenuation [Beta 0.24; (95% CI 0.04-0.51), p < 0.05). Despite similar volume, PAT attenuation was higher (p < 0.01) among demised patients.

CONCLUSION

In this study, we identified higher periaortic fat attenuation, despite similar fat volume, in patients with CE stroke.

Predicting haemodynamic significance of coronary stenosis with radiomics-based pericoronary adipose tissue characteristics

AIM

To investigate the diagnostic performance of the radiomics features of pericoronary adipose tissue (PCAT) in determining haemodynamically significant coronary artery stenosis as evaluated by fractional flow reserve (FFR).

MATERIALS AND METHODS

A total of 92 patients with clinically suspected coronary artery disease who underwent coronary computed tomography (CT) angiography (CCTA), invasive coronary angiography (ICA), and FFR examination within 1 month were included retrospectively, and 121 lesions were randomly assigned to the training and testing set. Based on manual segmentation of PCAT, 1,116 radiomics features were computed. After radiomics robustness assessment and feature selection, radiomics models were established using the different machine-learning algorithms. The area under the receiver operating characteristic (ROC) curve (AUC) and net reclassification index (NRI) were analysed to compare the discrimination and reclassification abilities of radiomics models.

RESULTS

Two radiomics features were selected after exclusions, and both were significantly higher in coronary arteries with FFR ≤0.8 than those with FFR >0.8. ROC analysis showed that the combination of CCTA and decision tree radiomics model achieved significantly higher diagnostic performance (AUC: 0.812) than CCTA alone (AUC: 0.599, p=0.015). Furthermore, the NRI of the combined model was 0.820 and 0.775 in the training and testing sets, respectively, suggesting the radiomics features of PCAT had were effective in classifying the haemodynamic significance of coronary stenosis.

CONCLUSIONS

Adding PCAT radiomics features to CCTA enabled identification of haemodynamically significant coronary artery stenosis.

The year 2020 in the European Heart Journal - Cardiovascular Imaging: part I

The European Heart Journal - Cardiovascular Imaging was launched in 2012 and has during these 9 years become one of the leading multimodality cardiovascular imaging journals. The journal is currently ranked as number 20 among all cardiovascular journals. Our journal is well established as one of the top cardiovascular journals and is the most important cardiovascular imaging journal in Europe. The most important studies published in our Journal in 2020 will be highlighted in two reports. Part I of the review will focus on studies about myocardial function and risk prediction, myocardial ischaemia, and emerging techniques in cardiovascular imaging, while Part II will focus on valvular heart disease, heart failure, cardiomyopathies, and congenital heart disease.

Human coronary inflammation by computed tomography: Relationship with coronary microvascular dysfunction

Background A new imaging metric using coronary computed tomography angiography (CCTA), addressing the peri-coronary adipose tissue (PCAT) computed tomography (CT) attenuation, has been clinically validated. This method provides information regarding coronary inflammation. It is unclear how coronary inflammation affects microvascular function. The non-invasive evaluation of coronary flow velocity reserve is widely used in clinical practice using Doppler measurement on the left anterior descending coronary artery (CFVR-lad) during stress-echocardiography (SE). We hypothesize that coronary inflammation affects CFVR-lad and, in the absence of overt CAD, they are significantly correlated. Methods We evaluated the relationship between coronary inflammation (by PCAT CT attenuation) and coronary microvascular function (by CFVR-lad) in subjects with no or non-obstructive (diameter stenosis <70%) coronary artery disease (CAD). Results Two-hundred and two subjects were enrolled in the study. The relationship between PCAT CT attenuation and CFVR-lad show a significant inverse relationship in the entire group of subjects enrolled in the study (r = -0.32, p < 0.001). Correlation between PCAT CT attenuation and CFVR-lad was significant in subjects with no or mild CAD-lad, while this was not the case in subjects with intermediate CAD-lad. The R and R² were respectively -0.40, -0.16 in subjects without CAD (p < 0.001) and - 0.35 and - 0.12 in subjects with mild CAD-lad (p = 0.001). Conclusions The main finding of the current study is the independent relationship between coronary microvascular function, by Doppler CFVR-lad during SE, in subjects without severely obstructive CAD in the left anterior descending coronary artery, and the level of local coronary inflammation, by PCAT attenuation measurement on CCTA.

The Emerging Role of CT-Based Imaging in Adipose Tissue and Coronary Inflammation

A large body of evidence arising from recent randomized clinical trials demonstrate the association of vascular inflammatory mediators with coronary artery disease (CAD). Vascular inflammation localized in the coronary arteries leads to an increased risk of CAD-related events, and produces unique biological alterations to local cardiac adipose tissue depots. Coronary computed tomography angiography (CTA) provides a means of mapping inflammatory changes to both epicardial adipose tissue (EAT) and pericoronary adipose tissue (PCAT) as independent markers of coronary risk. Radiodensity or attenuation of PCAT on coronary CTA, notably, provides indirect quantification of coronary inflammation and is emerging as a promising non-invasive imaging implement. An increasing number of observational studies have shown robust associations between PCAT attenuation and major coronary events, including acute coronary syndrome, and 'vulnerable' atherosclerotic plaque phenotypes that are associated with an increased risk of the said events. This review outlines the biological characteristics of both EAT and PCAT and provides an overview of the current literature on PCAT attenuation as a surrogate marker of coronary inflammation.

Prognostic Value of RCA Pericoronary Adipose Tissue CT-Attenuation Beyond High-Risk Plaques, Plaque Volume, and Ischemia

OBJECTIVES

This study was designed to assess the prognostic value of pericoronary adipose tissue computed tomography attenuation (PCATa) beyond quantitative coronary computed tomography angiography (CCTA)-derived plaque volume and positron emission tomography (PET) determined ischemia.

BACKGROUND

Inflammation plays a crucial role in atherosclerosis. PCATa has been shown to assess coronary-specific inflammation and is of prognostic value in patients with suspected coronary artery disease (CAD).

METHODS

A total of 539 patients who underwent CCTA and [¹⁵O]H₂O PET perfusion imaging because of suspected CAD were included. Imaging assessment included coronary artery calcium score (CACS), presence of obstructive CAD (≥50% stenosis) and high-risk plaques (HRPs), total plaque volume (TPV), calcified/noncalcified plaque volume (CPV/NCPV), PCATa, and myocardial ischemia. The endpoint was a composite of death and nonfatal myocardial infarction. Prognostic thresholds were determined for quantitative CCTA variables.

RESULTS

During a median follow-up of 5.0 (interquartile range: 4.7 to 5.0) years, 33 events occurred. CACS >59 Agatston units, obstructive CAD, HRPs, TPV >220 mm³, CPV >110 mm³, NCPV >85 mm³, and myocardial ischemia were associated with shorter time to the endpoint with unadjusted hazard ratios (HRs) of 4.17 (95% confidence interval [CI]: 1.80 to 9.64), 4.88 (95% CI: 1.88 to 12.65), 3.41 (95% CI: 1.72 to 6.75), 7.91 (95% CI: 3.05 to 20.49), 5.82 (95% CI: 2.40 to 14.10), 8.07 (95% CI: 3.33 to 19.55), and 4.25 (95% CI: 1.84 to 9.78), respectively (p < 0.05 for all). Right coronary artery (RCA) PCATa above scanner specific thresholds was associated with worse prognosis (unadjusted HR: 2.84; 95% CI: 1.44 to 5.63; p = 0.003), whereas left anterior descending artery and circumflex artery PCATa were not related to outcome. RCA PCATa above scanner specific thresholds retained is prognostic value adjusted for imaging variables and clinical characteristics associated with the endpoint (adjusted HR: 2.45; 95% CI: 1.23 to 4.93; p = 0.011).

CONCLUSIONS

Parameters associated with atherosclerotic burden and ischemia were more strongly associated with outcome than RCA PCATa. Nonetheless, RCA PCATa was of prognostic value beyond clinical characteristics, CACS, obstructive CAD, HRPs, TPV, CPV, NCPV, and ischemia.

Imaging of the Pericoronary Adipose Tissue (PCAT) Using Cardiac Computed Tomography: Modern Clinical Implications

Modern coronary computed tomography angiography (CTA) is the gold standard to visualize the epicardial adipose tissue (EAT) and pericoronary adipose tissue (PCAT). The EAT is a metabolic active fat depot enclosed by the visceral pericardium and surrounds the coronary arteries. In disease states with increased EAT volume and dysfunctional adipocytes, EAT secretes an increased amount of adipocytokines and the resulting imbalance of proinflammatory and anti-inflammatory mediators potentially causes atherogenic effects on the coronary vessel wall in a paracrine way ("outside-to-inside" signaling). These EAT-induced atherogenic effects are reported to increase the risk for the development of coronary artery disease, myocardial ischemia, high-risk plaque features, and future major adverse cardiac events. Coronary inflammation plays a key role in the development and progression of coronary artery disease; however, its noninvasive detection remains challenging. In future, this clinical dilemma might be changed by the CTA-derived analysis of the PCAT. On the basis of the concept of an "inside-to-outside" signaling between the inflamed coronary vessel wall and the surrounding PCAT recent evidence demonstrates that PCAT computed tomography attenuation especially around the right coronary artery derived from routine CTA is a promising imaging biomarker and "sensor" to noninvasively detect coronary inflammation. This review summarizes the biological and technical principles of CTA-derived PCAT analysis and highlights its clinical implications to improve modern cardiovascular prevention strategies.

Pericoronary adipose tissue CT attenuation and volume: Diagnostic performance for hemodynamically significant stenosis in patients with suspected coronary artery disease

OBJECTIVES

The aim of this study was to investigate the diagnostic abilities of both pericoronary adipose tissue (PCAT) CT attenuation and volume for the predication hemodynamic significance of coronary artery stenosis as evaluated by fractional flow reserve (FFR).

METHODS

Patients with ≥ 30 % in at least 1 major epicardial coronary artery were retrospectively included. Furthermore, all eligible patients underwent coronary computed tomography angiography (CCTA) and invasive coronary angiography (ICA) as well as FFR within 1 month. PCAT CT attenuation and volume around ischemic and non-ischemic coronary stenosis were measured and compared. The diagnostic accuracy of PCAT CT attenuation and volume for the identification of hemodynamically significant stenosis was determined against the reference standard of FFR ≤ 0.80.

RESULTS

A total of 61 patients (mean age, 57.8 years ± 11.8) with 77 vessels were included. Average PCAT CT attenuation of all vessels was -70.3 ± 7.4 HU. PCAT CT attenuation in coronary arteries with hemodynamically significant stenosis (FFR ≤ 0.80) (-65.6 ± 5.9 HU) was significantly higher than those with FFR > 0.80 (-75.3 ± 5.4 HU; p = 0.000). There was a strong correlation between FFR and PCAT CT attenuation (r = 0.64, p < 0.001). However, no significant difference in PCAT volume was observed between FFR ≤ 0.8 (5.0 ± 3.5 cm³) and FFR > 0.80 (5.5 ± 3.7 cm³, p = 0.511). The diagnostic accuracy was significantly higher in the combination of CCTA and PCAT CT attenuation compared with CCTA alone (area under the curve: 0.869 vs. 0.569, p < 0.001).

CONCLUSIONS

PCAT CT attenuation but not volume was related to the hemodynamic significance of coronary artery stenosis. For the patients with suspected coronary artery disease, after adding of PCAT CT attenuation to CCTA, the diagnostic ability for the identification of ischemic coronary stenosis was significantly improved.

Clinical Significance of Increased Computed Tomography Attenuation of Periaortic Adipose Tissue in Patients With Abdominal Aortic Aneurysms

BACKGROUND

Recent imaging studies reported an association between vascular inflammation and progression of abdominal aortic aneurysm (AAA). This study investigated the clinical significance of periaortic adipose tissue inflammation derived from multidetector computed tomography angiography (MDCTA).Methods and Results:Patients with asymptomatic AAA (n=77) who underwent an index and >6 months follow-up MDCTA examinations were retrospectively investigated. MDCTA analysis included AAA diameter and the periaortic adipose tissue attenuation index (PAAI). The PAAI was defined as the mean CT attenuation value within a predefined range from -190 to -30 Hounsfield units of adipose tissue surrounding the AAA. The growth rate of the AAA was calculated as the change in diameter. AAA progression (AP) was defined as an AAA growth rate ≥5 mm/year. Univariate and multivariate logistic regression analysis were performed to determine the predictors of AP. AP was observed in 19 patients (24.7%), the median baseline AAA diameter was 38.9 mm (interquartile range [IQR] 32.7-42.9 mm), and the median growth rate was 3.1 mm/year (IQR 1.5-4.9 mm/year). Baseline AAA diameter (odds ratio [OR] 1.16; 95% confidence interval [CI] 1.05-1.28; P=0.001) and PAAI (OR 1.12; 95% CI 1.05-1.20; P=0.004) were independent predictors of AP.

CONCLUSIONS

PAAI was an independent and significant predictor of AP, supporting the notion that local adipose tissue inflammation may contribute to aortic remodeling.

Advanced measurements of coronary calcium scores: how does it affect current clinical practice?

Coronary artery calcium (CAC) scoring has emerged as a marker of the burden of atheromatous disease and has been included in scoring systems. The practice of myocardial revascularization, considering percutaneous procedures or surgical strategies, is dramatically changing over years and the prognostic significance of CAC scoring is gradually being conceived. In this interdisciplinary scenario, vessel specific calcium scoring, mapping of coronary calcification and its integration with functional assessment of coronary artery disease might change the future decisions in the catheterization lab and operative theaters. This article summarizes CAC evaluation techniques and its implications in clinical practice.

Focal pericoronary adipose tissue attenuation is related to plaque presence, plaque type, and stenosis severity in coronary CTA

Objectives

To investigate the association of pericoronary adipose tissue mean attenuation (PCAT_MA) with coronary artery disease (CAD) characteristics on coronary computed tomography angiography (CCTA).

Methods

We retrospectively investigated 165 symptomatic patients who underwent third-generation dual-source CCTA at 70kVp: 93 with and 72 without CAD (204 arteries with plaque, 291 without plaque). CCTA was evaluated for presence and characteristics of CAD per artery. PCAT_MA was measured proximally and across the most severe stenosis. Patient-level, proximal PCAT_MA was defined as the mean of the proximal PCAT_MA of the three main coronary arteries. Analyses were performed on patient and vessel level.

Results

Mean proximal PCAT_MA was −96.2 ± 7.1 HU and −95.6 ± 7.8HU for patients with and without CAD (p = 0.644). In arteries with plaque, proximal and lesion-specific PCAT_MA was similar (−96.1 ± 9.6 HU, −95.9 ± 11.2 HU, p = 0.608). Lesion-specific PCAT_MA of arteries with plaque (−94.7 HU) differed from proximal PCAT_MA of arteries without plaque (−97.2 HU, p = 0.015). Minimal stenosis showed higher lesion-specific PCAT_MA (−94.0 HU) than severe stenosis (−98.5 HU, p = 0.030). Lesion-specific PCAT_MA of non-calcified, mixed, and calcified plaque was −96.5 HU, −94.6 HU, and −89.9 HU (p = 0.004). Vessel-based total plaque, lipid-rich necrotic core, and calcified plaque burden showed a very weak to moderate correlation with proximal PCAT_MA.

Conclusions

Lesion-specific PCAT_MA was higher in arteries with plaque than proximal PCAT_MA in arteries without plaque. Lesion-specific PCAT_MA was higher in non-calcified and mixed plaques compared to calcified plaques, and in minimal stenosis compared to severe; proximal PCAT_MA did not show these relationships. This suggests that lesion-specific PCAT_MA is related to plaque development and vulnerability.

Key Points

• In symptomatic patients undergoing CCTA at 70 kVp, PCAT_MAwas higher in coronary arteries with plaque than those without plaque.

• PCAT_MAwas higher for non-calcified and mixed plaques compared to calcified plaques, and for minimal stenosis compared to severe stenosis.

• In contrast to PCAT_MAmeasurement of the proximal vessels, lesion-specific PCAT_MAshowed clear relationships with plaque presence and stenosis degree.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-07882-1.

Exploring the Role of Epicardial Adipose Tissue in Coronary Artery Disease From the Difference of Gene Expression

Objectives

Epicardial adipose tissue (EAT) is closely adjacent to the coronary arteries and myocardium, its role as an endocrine organ to affect the pathophysiological processes of the coronary arteries and myocardium has been increasingly recognized. However, the specific gene expression profiles of EAT in coronary artery disease (CAD) has not been well characterized. Our aim was to investigate the role of EAT in CAD at the gene level.

Methods

Here, we compared the histological and gene expression difference of EAT between CAD and non-CAD. We investigated the gene expression profiles in the EAT of patients with CAD through the high-throughput RNA sequencing. We performed bioinformatics analysis such as functional enrichment analysis and protein-protein interaction network construction to obtain and verify the hub differentially expressed genes (DEGs) in the EAT of CAD.

Results

Our results showed that the size of epicardial adipocytes in the CAD group was larger than in the control group. Our findings on the EAT gene expression profiles of CAD showed a total of 747 DEGs (fold change >2, p value <0.05). The enrichment analysis of DEGs showed that more pro-inflammatory and immunological genes and pathways were involved in CAD. Ten hub DEGs (GNG3, MCHR1, BDKRB1, MCHR2, CXCL8, CXCR5, CCR8, CCL4L1, TAS2R10, and TAS2R41) were identified.

Conclusion

Epicardial adipose tissue in CAD shows unique gene expression profiles and may act as key regulators in the CAD pathological process.

From CT to artificial intelligence for complex assessment of plaque-associated risk

The recent technological developments in the field of cardiac imaging have established coronary computed tomography angiography (CCTA) as a first-line diagnostic tool in patients with suspected coronary artery disease (CAD). CCTA offers robust information on the overall coronary circulation and luminal stenosis, also providing the ability to assess the composition, morphology, and vulnerability of atherosclerotic plaques. In addition, the perivascular adipose tissue (PVAT) has recently emerged as a marker of increased cardiovascular risk. The addition of PVAT quantification to standard CCTA imaging may provide the ability to extract information on local inflammation, for an individualized approach in coronary risk stratification. The development of image post-processing tools over the past several years allowed CCTA to provide a significant amount of data that can be incorporated into machine learning (ML) applications. ML algorithms that use radiomic features extracted from CCTA are still at an early stage. However, the recent development of artificial intelligence will probably bring major changes in the way we integrate clinical, biological, and imaging information, for a complex risk stratification and individualized therapeutic decision making in patients with CAD. This review aims to present the current evidence on the complex role of CCTA in the detection and quantification of vulnerable plaques and the associated coronary inflammation, also describing the most recent developments in the radiomics-based machine learning approach for complex assessment of plaque-associated risk.