Comparison of Quantity of Coronary Atherosclerotic Plaques Detected by Computed Tomography Versus Angiography

Impact of smoking in patients with suspected coronary artery disease in the randomised DISCHARGE trial

OBJECTIVES

To investigate if the effect of cardiac computed tomography (CT) vs. invasive coronary angiography (ICA) on cardiovascular events differs based on smoking status.

MATERIALS AND METHODS

This pre-specified subgroup analysis of the pragmatic, prospective, multicentre, randomised DISCHARGE trial (NCT02400229) involved 3561 patients with suspected coronary artery disease (CAD). The primary endpoint was major adverse cardiovascular events (MACE: cardiovascular death, non-fatal myocardial infarction, or stroke). Secondary endpoints included an expanded MACE composite (MACE, transient ischaemic attack, or major procedure-related complications).

RESULTS

Of 3445 randomised patients with smoking data (mean age 59.1 years + / - 9.7, 1151 men), at 3.5-year follow-up, the effect of CT vs. ICA on MACE was consistent across smoking groups (p for interaction = 0.98). The percutaneous coronary intervention rate was significantly lower with a CT-first strategy in smokers and former smokers (p = 0.01 for both). A CT-first strategy reduced the hazard of major procedure-related complications (HR: 0.21, 95% CI: 0.03, 0.81; p = 0.045) across smoking groups. In current smokers, the expanded MACE composite was lower in the CT- compared to the ICA-first strategy (2.3% (8) vs 6.0% (18), HR: 0.38; 95% CI: 0.17, 0.88). The rate of non-obstructive CAD was significantly higher in all three smoking groups in the CT-first strategy.

CONCLUSION

For patients with stable chest pain referred for ICA, the clinical outcomes of CT were consistent across smoking status. The CT-first approach led to a higher detection rate of non-obstructive CAD and fewer major procedure-related complications in smokers.

CLINICAL RELEVANCE STATEMENT

This pre-specified sub-analysis of the DISCHARGE trial confirms that a CT-first strategy in patients with stable chest pain referred for invasive coronary angiography with an intermediate pre-test probability of coronary artery disease is as effective as and safer than invasive coronary angiography, irrespective of smoking status.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02400229.

KEY POINTS

• No randomised studies have assessed smoking status on CT effectiveness in symptomatic patients referred for invasive coronary angiography. • A CT-first strategy results in comparable adverse events, fewer complications, and increased coronary artery disease detection, irrespective of smoking status. • A CT-first strategy is safe and effective for stable chest pain patients with intermediate pre-test probability for CAD, including never smokers.

HIV indirectly accelerates coronary artery disease by promoting the effects of risk factors: longitudinal observational study

Our objective was to assess whether human immunodeficiency virus (HIV)-infection directly or indirectly promotes the progression of clinical characteristics of coronary artery disease (CAD). 300 African Americans with asymptomatic CAD (210 male; age: 48.0 ± 7.2 years; 226 HIV-infected) who underwent coronary CT angiography at two time points (mean follow-up: 4.0 ± 2.3 years) were randomly selected from 1429 participants of a prospective epidemiological study between May 2004 and August 2015. We calculated Agatston-scores, number of coronary plaques and segment stenosis score (SSS). Linear mixed models were used to assess the effects of HIV-infection, atherosclerotic cardiovascular disease (ASCVD) risk, years of cocaine use on CAD. There was no significant difference in annual progression rates between HIV-infected and—uninfected regarding Agatston-scores (10.8 ± 25.1/year vs. 7.2 ± 17.8/year, p = 0.17), the number of plaques (0.2 ± 0.3/year vs. 0.3 ± 0.5/year, p = 0.11) or SSS (0.5 ± 0.8/year vs. 0.5 ± 1.3/year, p = 0.96). Multivariately, HIV-infection was not associated with Agatston-scores (8.3, CI: [− 37.2–53.7], p = 0.72), the number of coronary plaques (− 0.1, CI: [− 0.5–0.4], p = 0.73) or SSS (− 0.1, CI: [− 1.0–0.8], p = 0.84). ASCVD risk scores and years of cocaine-use significantly increased all CAD outcomes among HIV-infected individuals, but not among HIV-uninfected. Importantly, none of the HIV-medications were associated with any of the CAD outcomes. HIV-infection is not directly associated with CAD and therefore HIV-infected are not destined to have worse CAD profiles. However, HIV-infection may indirectly promote CAD progression as risk factors may have a more prominent role in the acceleration of CAD in these patients.

CAD-RADS may underestimate coronary plaque progression as detected by serial CT angiography

Aims

We wished to assess whether different clinical definitions of coronary artery disease (CAD) [segment stenosis and involvement score (SSS, SIS), Coronary Artery Disease—Reporting and Data System (CAD-RADS)] affect which patients are considered to progress and which risk factors affect progression.

Methods and results

We enrolled 115 subsequent patients (60.1 ± 9.6 years, 27% female) who underwent serial coronary computed tomography angiography (CTA) imaging with >1year between the two examinations. CAD was described using SSS, SIS, and CAD-RADS. Linear mixed models were used to investigate the effects of risk factors on the overall amount of CAD and the effect on annual progression rate of different definitions. Coronary plaque burdens were SSS 4.63 ± 4.06 vs. 5.67 ± 5.10, P < 0.001; SIS 3.43 ± 2.53 vs. 3.89 ± 2.65, P < 0.001; CAD-RADS 0:8.7% vs. 0.0% 1:44.3% vs. 40.9%, 2:34.8% vs. 40.9%, 3:7.0% vs. 9.6% 4:3.5% vs. 6.1% 5:1.7% vs. 2.6%, P < 0.001, at baseline and follow-up, respectively. Overall, 53.0%, 29.6%, and 28.7% of patients progressed over time based on SSS, SIS, and CAD-RADS, respectively. Of the patients who progressed based on SSS, only 54% showed changes in CAD-RADS. Smoking and diabetes increased the annual progression rate of SSS by 0.37/year and 0.38/year, respectively (both P < 0.05). Furthermore, each year increase in age raised SSS by 0.12 [confidence interval (CI) 0.05–0.20, P = 0.001] and SIS 0.10 (CI 0.06–0.15, P < 0.001), while female sex was associated with 2.86 lower SSS (CI −4.52 to −1.20, P < 0.001) and 1.68 SIS values (CI −2.65 to −0.77, P = 0.001).

Conclusion

CAD-RADS could not capture the progression of CAD in almost half of patients with serial CTA. Differences in CAD definitions may lead to significant differences in patients who are considered to progress, and which risk factors are considered to influence progression.

Computed tomography of coronary artery atherosclerosis: A review

Coronary artery atherosclerosis resulting in ischemic cardiac disease is the leading cause of mortality in the United States. In symptomatic patients, invasive diagnostic methods like catheter angiography, intravascular ultrasound, or vascular endoscopy may be used. However, for primary prevention of atherosclerotic coronary artery disease in asymptomatic patients, non-invasive methods are more commonly utilized like stress imaging, single-photon emission computed tomography (SPECT) and coronary artery calcification scoring. Coronary computed tomographic angiography (CCTA) is an excellent diagnostic tool for detection of coronary artery plaque and ability to identify resultant stenoses with an excellent negative predictive value which can potentially result in optimal exclusion of the presence of coronary artery disease. Long term follow up after a negative CCTA has repeatedly demonstrated very low incidence of future adverse coronary events, attesting its predictive value. CCTA based management is associated with improved CAD outcome in stable angina. Coronary CTA is valuable in acute chest pain evaluation in the emergency department helping in better triage. CT perfusion and CT-FFR are both very promising tools for assessment of hemodynamic significance of coronary artery stenosis.

Pericoronary Adipose Tissue Attenuation Is Associated with High-Risk Plaque and Subsequent Acute Coronary Syndrome in Patients with Stable Coronary Artery Disease

BACKGROUND

High-risk plaques (HRP) detected on coronary computed tomography angiography (CTA) confer an increased risk of acute coronary syndrome (ACS). Pericoronary adipose tissue attenuation (PCAT) is a novel biomarker of coronary inflammation. This study aimed to evaluate the association of PCAT with HRP and subsequent ACS development in patients with stable coronary artery disease (CAD).

METHODS

Patients with stable CAD who underwent coronary CTA from 2011 to 2016 and had available outcome data were included. We studied 41 patients with HRP propensity matched to 41 controls without HRP (60 ± 10 years, 67% males). PCAT was assessed using semi-automated software on a per-patient basis in the proximal right coronary artery (PCATRCA) and a per-lesion basis (PCATLesion) around HRP in cases and the highest-grade stenosis lesions in controls.

RESULTS

PCATRCA and PCATLesion were higher in HRP patients than controls (PCATRCA: -80.7 ± 6.50 HU vs. -84.2 ± 8.09 HU, p = 0.03; PCATLesion: -79.6 ± 7.86 HU vs. -84.2 ± 10.3 HU, p = 0.04), and were also higher in men (PCATRCA: -80.5 ± 7.03 HU vs. -86.1 ± 7.08 HU, p < 0.001; PCATLesion: -79.6 ± 9.06 HU vs. -85.2 ± 7.96 HU, p = 0.02). Median time to ACS was 1.9 years, within a median follow-up of 5.3 years. PCATRCA alone was higher in HRP patients who subsequently presented with ACS (-76.8 ± 5.69 HU vs. -82.0 ± 6.32 HU, p = 0.03). In time-dependent analysis, ACS was associated with HRP and PCATRCA.

CONCLUSIONS

PCAT attenuation is increased in stable CAD patients with HRP and is associated with subsequent ACS development. Further investigation is required to determine the clinical implications of these findings.

Usefulness of Coronary Computed Tomographic Angiography to Evaluate Coronary Artery Disease in Radiotherapy-Treated Breast Cancer Survivors

Breast cancer is the most commonly diagnosed cancer in women and radiotherapy is a widely used treatment approach. However, there is an increased risk of coronary artery disease and cardiac death in women treated with radiotherapy. The present study was undertaken to clarify the relation between radiotherapy and coronary disease in women with previous breast irradiation using coronary computed tomographic angiography (CCTA). We conducted a retrospective analysis of women with a history of right or left-sided breast cancer (RBC; LBC) treated with radiotherapy who subsequently underwent CCTA. RBC patients who had reduced radiation doses to the myocardium served as controls. Patients (n = 6,593) with a history of nonmetastatic breast cancer treated with radiotherapy were screened for completion of CCTA; 49 LBC and 45 RBC women were identified. Age and risk factor matched patients with LBC had higher rates of coronary disease compared with RBC patients; left anterior descending (LAD) coronary artery (76% vs 31% [p < 0.001]), left circumflex (33% vs. 6.7% [p = 0.004]), and right coronary artery (37% vs 13% [p = 0.018]). Mean LAD radiation dose and mean heart dose strongly correlated with coronary disease, with a 21% higher incidence of disease in the LAD per Gy for mean LAD dose and a 95% higher incidence of disease in the LAD per Gy for mean heart dose. In conclusion, LBC patients treated with radiotherapy have a significantly higher incidence of coronary disease when compared with a matched group of patients treated for RBC. Radiation doses correlated with the incidence of coronary disease.

Hypermethylation of miR-181b in monocytes is associated with coronary artery disease and promotes M1 polarized phenotype via PIAS1-KLF4 axis

Background

Dysregulated microRNAs are involved in the macrophage polarization and atherosclerotic development. Apart from microRNAs, alteration in DNA methylation is considered as one of the most frequent epigenetic changes. The purpose of the research is to investigate the altered methylation status of miR-181b in the circulating monocytes from patients with coronary artery disease (CAD) and explore the underlying mechanisms.

Methods

We examined the methylation status of miR-181b in purified circulating monocytes from patients with CAD and healthy controls. We then transfected monocytes with miR-181b mimics and determined the role of miR-181b on the phenotypic switch of macrophages and inflammatory response. DNA methylation levels determined by MethyLight PCR and pyrosequencing at the promoter of miR-181b significantly increased in CAD patients. Based on TargetScan database, we identified PIAS1 as the target gene of miR-181b and explored the interaction of miR-181b and PIAS1 by Dual-Luciferase assay, quantitative PCR and immunoblots. We also investigated the role of miR-181b and PIAS1 on macrophage polarization and inflammation.

Results

Hypermethylation at the promoter of miR-181b directly contributed to the decrease of miR-181b activity and expression. Overexpression of miR-181b reduced M1 polarization and facilitated M2 polarization determined by quantitative PCR. While knockdown of PIAS1 induced KLF4 degradation and SUMOylation in monocytes, miR-181b mimics reverse the KLF4 SUMOylation via suppression of PIAS1. Moreover, KLF4 SUMOylation by PIAS1 reversed M1 polarization induced by depletion of miR-181b in monocytes.

Conclusions

Hypermethylation of miR-181b induces M1 polarization and promotes atherosclerosis through activation of PIAS1 and KLF4 SUMOylation in macrophages.

Plasmonic Copper Sulfide Nanoparticles Enable Dark Contrast in Optical Coherence Tomography

Optical coherence tomography (OCT) is an imaging technique affording noninvasive optical biopsies. Like for other imaging techniques, the use of dedicated contrast agents helps better discerning biological features of interest during the clinical practice. Although bright OCT contrast agents have been developed, no dark counterpart has been proposed yet. Herein, plasmonic copper sulfide nanoparticles as the first OCT dark contrast agents working in the second optical transparency window are reported. These nanoparticles virtually possess no light scattering capabilities at the OCT working wavelength (≈1300 nm); thus, they exclusively absorb the probing light, which in turn results in dark contrast. The small size of the nanoparticles and the absence of apparent cytotoxicity support the amenability of this system to biomedical applications. Importantly, in the pursuit of systems apt to yield OCT dark contrast, a library of copper sulfide nanoparticles featuring plasmonic resonances spanning the three optical transparency windows is prepared, thus highlighting the versatility and potential of these systems in light-controlled biomedical applications.

Undiagnosed coronary artery disease in long-term type 1 diabetes. The Dialong study

AIMS

We studied the total prevalence of obstructive coronary artery disease (CAD), undiagnosed CAD and absent CAD in persons with ≥45-year duration of type 1 diabetes (T1D) versus controls, and associations with mean HbA_1c, LDL-cholesterol and blood pressure over 2-3 decades.

METHODS

We included 76% (n = 103) of all persons with T1D diagnosed ≤1970 attending a diabetes center and 63 controls without diabetes. We collected 20-30 years of HbA_1c, LDL-cholesterol and blood pressure measurements. Participants without previously diagnosed coronary heart disease (CHD) underwent Computed Tomography Coronary Angiography (CTCA). Undiagnosed obstructive CAD was defined as any coronary stenosis >50% on CTCA, absent CAD as no detected plaque, and total obstructive CAD as either obstructive CAD on CTCA or previous CHD diagnosis.

RESULTS

The prevalence of undiagnosed, absent and obstructive CAD was 24% (21/88), 16% (14/88) and 35% (36/103) in T1D versus 10% (6/60), 50% (30/60) and 14% (9/63) in controls (all p < 0.05). Mean HbA_1c was associated with undiagnosed obstructive CAD (OR 2.30 95% C.I. 1.13-4.69), while mean LDL-cholesterol was inversely associated with absent CAD (0.12, 0.04-0.43).

CONCLUSIONS

The prevalence of undiagnosed obstructive CAD was high (24%) in this cohort of long-term survivors with T1D. Mean LDL-cholesterol and HbA_1c were associated with CAD.

Coronary Artery Disease-Reporting and Data System (CAD-RADS): strengths and limitations

A new standardised reporting system was introduced recently for coronary computed tomography (CT) angiography interpretation called CAD-RADS (Coronary Artery Disease-Reporting and Data System). Like any other new reporting platform, CAD-RADS has both advantages and disadvantages. Consistency in reporting, better clarity of communication, and more streamlined clinical recommendations are the major strengths of CAD-RADS. It has many limitations such as misinterpretation of CT angiography findings inherent to any CT angiography examination and unique disadvantages like misclassification of abnormalities, potential to misguide the referring physicians by suggesting management based on a single score. In addition, CAD-RADS does not include the details on location and extent of disease in the coronary arteries, coronary anomalies and other cardiac and extra cardiac findings.

CAD-RADS - a new clinical decision support tool for coronary computed tomography angiography

Coronary computed tomography angiography (CTA) has been established as an accurate method to non-invasively assess coronary artery disease (CAD). The proposed 'Coronary Artery Disease Reporting and Data System' (CAD-RADS) may enable standardised reporting of the broad spectrum of coronary CTA findings related to the presence, extent and composition of coronary atherosclerosis. The CAD-RADS classification is a comprehensive tool for summarising findings on a per-patient-basis dependent on the highest-grade coronary artery lesion, ranging from CAD-RADS 0 (absence of CAD) to CAD-RADS 5 (total occlusion of a coronary artery). In addition, it provides suggestions for clinical management for each classification, including further testing and therapeutic options. Despite some limitations, CAD-RADS may facilitate improved communication between imagers and patient caregivers. As such, CAD-RADS may enable a more efficient use of coronary CTA leading to more accurate utilisation of invasive coronary angiograms. Furthermore, widespread use of CAD-RADS may facilitate registry-based research of diagnostic and prognostic aspects of CTA.

KEY POINTS

• CAD-RADS is a tool for standardising coronary CTA reports. • CAD-RADS includes clinical treatment recommendations based on CTA findings. • CAD-RADS has the potential to reduce variability of CTA reports.

Experience With an On-Site Coronary Computed Tomography-Derived Fractional Flow Reserve Algorithm for the Assessment of Intermediate Coronary Stenoses

Fractional flow reserve (FFR) derived from coronary computed tomography angiography (CTA) is a new technique for the diagnosis of ischemic coronary artery stenoses. The aim of this prospective study was to evaluate the diagnostic performance of a novel on-site computed tomography-based fractional flow reserve algorithm (CT-FFR) compared with invasive FFR as the gold standard, and to determine whether its diagnostic performance is affected by interobserver variations in lumen segmentation. We enrolled 44 consecutive patients (64.6 ± 8.9 years, 34% female) with 60 coronary atherosclerotic lesions who underwent coronary CTA and invasive coronary angiography in 2 centers. An FFR value ≤0.8 was considered significant. Coronary CTA scans were evaluated by 2 expert readers, who manually adjusted the semiautomated coronary lumen segmentations for effective diameter stenosis (EDS) assessment and on-site CT-FFR simulation. The mean CT-FFR value was 0.77 ± 0.15, whereas the mean EDS was 43.6 ± 16.9%. The sensitivity, specificity, positive predictive value, and negative predictive value of CT-FFR versus EDS with a cutoff of 50% were the following: 91%, 72%, 63%, and 93% versus 52%, 87%, 69%, and 77%, respectively. The on-site CT-FFR demonstrated significantly better diagnostic performance compared with EDS (area under the curve 0.89 vs 0.74, respectively, p <0.001). The CT-FFR areas under the curve of the 2 readers did not show any significant difference (0.89 vs 0.88, p = 0.74). In conclusion, on-site CT-FFR simulation is feasible and has better diagnostic performance than anatomic stenosis assessment. Furthermore, the diagnostic performance of the on-site CT-FFR simulation algorithm does not depend on the readers' semiautomated lumen segmentation adjustments.

The risk of coronary artery disease estimated non-invasively in patients with essential hypertension environmentally exposed to cigarette smoke

BACKGROUND

The relationship between environmental exposure of non-smokers to cigarette smoke and the coronary artery calcium scores has not been sufficiently documented. The aim of the study was to identify the relationship between environmental exposure to cigarette smoke and the risk of coronary artery disease (CAD) estimated non-invasively through measurement of coronary artery calcium score by computed tomography in patients with essential hypertension.

MATERIAL AND METHODS

The study was conducted on 67 patients with essential hypertension, non-smokers environmentally exposed to cigarette smoke (group A) and on 67 patients with essential hypertension, non-smokers not exposed to cigarette smoke (group B), selected using the case to case. Environmental exposure to cigarette smoke was evaluated using a questionnaire. The risk of development of coronary artery disease was estimated non-invasively through measurement of coronary artery calcium score (CACS) by computed tomography.

RESULTS

Group A was characterised by significantly higher CACS and left anterior descending (LADCS) calcium scores than group B. Compared to group B, group A had significantly higher percentage of patients with significant risk of CAD estimated on the basis of CACS values, and significantly lower percentage of patients with practically no risk of CAD estimated with the same method. Advanced age, peripheral artery diseases and environmental exposure to cigarette smoke are independent risk factors associated with increased CACS and LADCS values. In addition, higher BMI and hypercholesterolemia are independent risk factors for increased values of LADCS.

CONCLUSIONS

In patients with essential hypertension environmental exposure to cigarette smoke may result in elevated risk of coronary artery disease estimated non-invasively through measurement of coronary artery calcium score by computed tomography.

Inverse association between hyperthymic affective temperament and coronary atherosclerosis: A coronary computed tomography angiography study

OBJECTIVE

A bidirectional relationship exists between psychiatric disorders and cardiovascular diseases, however less is known with regards to personality traits. Accumulating data suggest that affective temperaments are both associated with psychiatric and somatic diseases. The aim of our study was to evaluate the associations between different affective temperaments and the presence of coronary atherosclerosis.

METHODS

200 consecutive patients referred to coronary computed tomography angiography (CCTA) due to suspected coronary artery disease (CAD) were included in our study. Medical history and demographic parameters were recorded and all patients completed the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego Autoquestionnaire (TEMPS-A) and the Beck Depression Inventory (BDI). The presence of coronary artery disease was evaluated based on the CCTA images.

RESULTS

39 patients were free of any coronary atherosclerosis (CCTA-) and 161 had coronary atherosclerosis (CCTA+). Hyperthymic affective temperament score was higher in CCTA- subjects as compared to CCTA+ (13.1±3.0 vs 11.5±4.6, p=0.010, respectively). Hyperthymic affective temperament score showed a significant independent, inverse relationship with coronary atherosclerosis (OR: 0.91 CI: 0.82-0.99, p=0.04).

CONCLUSION

Our results suggest that hyperthymic affective temperament is independently associated with the absence of CAD. It requires further research to delineate the mechanism mediating the effect of hyperthymia on better coronary artery health and establishing potential biochemical or behavioral factors, both of which could be exploited for prevention and treatment purposes. But it is plausible, that the evaluation of affective temperaments have importance both in relation with psychiatric and cardiovascular disorders.

Image Quality of Prospectively ECG-Triggered Coronary CT Angiography in Heart Transplant Recipients

OBJECTIVE

Cardiac allograft vasculopathy (CAV) is among the top causes of death 1 year after heart transplantation (HTx). Coronary CT angiography (CTA) is a potential alternative to invasive imaging in the diagnosis of CAV. However, the higher heart rate (HR) of HTx recipients prompts the use of retrospective ECG-gating, which is associated with higher radiation dose, a major concern in this patient population. Therefore, we sought to evaluate the feasibility and image quality of low-radiation-dose prospectively ECG-triggered coronary CTA in HTx recipients.

MATERIALS AND METHODS

In total, 1270 coronary segments were evaluated in 50 HTx recipients and 50 matched control subjects who did not undergo HTx. The control subjects were selected from our clinical database and were matched for age, sex, body mass index, HR, and coronary dominance. Scans were performed using 256-MDCT with prospective ECG-triggering. The degree of motion artifacts was evaluated on a per-segment basis on a 4-point Likert-type scale.

RESULTS

The median HR was 74.0 beats/min (interquartile range [IQR], 67.8-79.3 beats/min) in the HTx group and 73.0 beats/min (IQR, 68.5-80.0 beats/min) in the matched control group (p = 0.58). In the HTx group, more segments had diagnostic image quality compared with the control group (624/662 [94.3%] vs 504/608 [82.9%]; p < 0.001). The mean effective radiation dose was low in both groups (3.7 mSv [IQR, 2.4-4.3 mSv] in the HTx group vs 4.3 mSv [IQR, 2.6-4.3 mSv] in the control group; p = 0.24).

CONCLUSION

Prospectively ECG-triggered coronary CTA examinations of HTx recipients yielded diagnostic image quality with low radiation dose. Coronary CTA is a promising noninvasive alternative to routine catheterization during follow-up of HTx recipients to diagnose CAV.

Plaque imaging with CT-a comprehensive review on coronary CT angiography based risk assessment

CT based technologies have evolved considerably in recent years. Coronary CT angiography (CTA) provides robust assessment of coronary artery disease (CAD). Early coronary CTA imaging-as a gate-keeper of invasive angiography-has focused on the presence of obstructive stenosis. Coronary CTA is currently the only non-invasive imaging modality for the evaluation of non-obstructive CAD, which has been shown to contribute to adverse cardiac events. Importantly, improved spatial resolution of CT scanners and novel image reconstruction algorithms enable the quantification and characterization of atherosclerotic plaques. State-of-the-art CT imaging can therefore reliably assess the extent of CAD and differentiate between various plaque features. Recent studies have demonstrated the incremental prognostic value of adverse plaque features over luminal stenosis. Comprehensive coronary plaque assessment holds potential to significantly improve individual risk assessment incorporating adverse plaque characteristics, the extent and severity of atherosclerotic plaque burden. As a result, several coronary CTA based composite risk scores have been proposed recently to determine patients at high risk for adverse events. Coronary CTA became a promising modality for the evaluation of functional significance of coronary lesions using CT derived fractional flow reserve (FFR-CT) and/or rest/dynamic myocardial CT perfusion. This could lead to substantial reduction in unnecessary invasive catheterization procedures and provide information on ischemic burden of CAD. Discordance between the degree of stenosis and ischemia has been recognized in clinical landmark trials using invasive FFR. Both lesion stenosis and composition are possibly related to myocardial ischemia. The evaluation of lesion-specific ischemia using combined functional and morphological plaque information could ultimately improve the diagnostic performance of CTA and thus patient care. In this review we aimed to summarize current evidence on comprehensive coronary artery plaque assessment using coronary CTA.

Prospectively ECG-triggered high-pitch coronary CT angiography at 70 kVp with 30mL contrast agent: An intraindividual comparison with sequential scanning at 120 kVp with 60mL contrast agent

PURPOSE

To investigate image quality, radiation dose, and diagnostic efficiency of prospectively ECG-triggered high-pitch coronary CT angiography (CCTA) at 70 kVp with 30mL contrast agent intra-individually compared with routine CCTA protocol.

MATERIALS AND METHODS

One hundred and thirty eight patients with suspected coronary artery disease, body mass index (BMI)≤25kg/m² and heart rate (HR)≤70 beats per minute (bpm) underwent prospectively ECG-triggered high-pitch CCTA at 70 kVp and 30mL contrast agent (protocol A) and prospectively ECG-triggered sequential scanning at 120 kVp and 60mL contrast medium (protocol B). Objective and subjective image quality, radiation doses, and diagnostic accuracy were evaluated and compared between the two protocols.

RESULTS

Higher CT attenuation, higher noise, lower signal-to-noise ratios (SNRs) and lower contrast-to-noise ratios (CNRs) were found in protocol A than in protocol B (P<0.001). However, image quality of protocol A were diagnostic. In patients with BMI<23kg/m² or HR<60bpm, subjective image quality scores of some coronary arteries in protocol A were not significantly different from protocol B (P>0.05). Effective dose in protocol A has reduced by 96.7% compared with protocol B (P<0.001). No significant differences were found for diagnostic accuracy between the two protocols on a per-segment (P=0.513), per-vessel (P=0.317) and per-patient (P=0.125) basis.

CONCLUSIONS

Prospectively ECG-triggered high-pitch CCTA at 70kVp with 30mL contrast agent can reduce radiation dose but maintain image quality and high diagnostic accuracy in a selected, non-obese population.

Difference of coronary stenosis severity between systolic and diastolic phases in quantitative CT angiography

BACKGROUND

To compare the difference of coronary diameter stenosis by quantitative analysis of CT angiography (QCT) in the systolic (QCT-S) and diastolic phase (QCT-D) of the cardiac cycle, with invasive catheter angiography (QCA) as reference standard.

METHODS

A total of 109 patients (57.5 ± 10.6 years, 78.9% male) with suspected coronary artery disease (CAD) who underwent both CT angiography and invasive catheter angiography were retrospectively included in this study. Coronary diameter stenoses in systolic and diastolic coronary CTA reconstructions were compared with QCA.

RESULTS

Mean time interval between CT angiography and invasive angiography was 17.4 ± 4.4 days. QCT-D overestimated coronary diameter stenosis by 5.7%-8.5% while QCT-S overestimated coronary diameter stenosis by 9.4%-11.9% (p < 0.05). In calcified lesions, QCT-D overestimated coronary diameter stenosis by 13.2 ± 4.3%, while QCT-S overestimated by stenosis by 16.6 ± 4.3% (p < 0.05).

CONCLUSIONS

Coronary diameter stenosis was overestimated by QCT-D as well as QCT-S, respectively, when compared with QCA. Overestimation was more pronounced in calcified lesions.