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Increased attenuation of pericoronary adipose tissue (PCAT) around the right coronary artery (RCA) derived from coronary CTA might detect coronary inflammation. We investigated a potential association between RCA PCAT attenuation and serum levels of atherosclerosis-relevant cytokines and MACE (coronary revascularization, myocardial infarction and/or cardiac death).Blood samples of 293 clinically stable individuals (59.0 ​± ​9.8 years, 69% males) were analyzed for atherosclerosis-relevant cytokines including interleukin (IL)-2, IL- 4, IL-6, IL-7, IL-8, IL-10, IL-13, IL-15, IL-17, TNF-a, IP-10, CRP, MCP-1, MIP-1a, Eotaxin and GM-CSF. Subjects also underwent coronary calcium scoring (CCS) followed by CTA. PCAT CT attenuation was measured around the RCA using semi-automated software. Increased RCA PCAT attenuation was defined as PCAT attenuation above the 75th percentile (-73.5 HU). To assess MACE, 232 individuals were followed for a mean duration of 9.6 ​± ​2.1 years.In patients with increased RCA PCAT attenuation the serum levels of MCP-1 were increased (p ​ ​0.01), whereas levels of anti-inflammatory mediators IL-4 and -13 were significantly reduced (each p ​ ​0.05). Adipocytokine MCP-1 (r ​= ​0.23, p ​ ​0.01) and pro-inflammatory mediator IL-7 (r ​= ​0.12, p ​= ​0.04) showed a mild positive correlation with RCA PCAT attenuation, whereas anti-inflammatory mediators Il-4, -10 and -13 correlated inversely (each r-0.12, each p ​ ​0.05). 40/232 patients experienced MACE during follow-up. In multivariable Cox regression analysis increased RCA PCAT attenuation was shown to be an independent predictor of MACE (HR 2.01, p ​= ​0.044).Increased RCA PCAT CT attenuation shows a weak association with serum levels of selected atherosclerosis-relevant inflammatory biomarkers. Increased RCA PCAT attenuation is an independent predictor of MACE and may potentially guide future prevention strategies in stable patients.

Background Studies have observed higher incidence of cardiovascular mortality in South Asians (SA), and lower prevalence in East Asians (EA), compared with Caucasians. These observations are not entirely explained by ethnic differences in cardiovascular risk factors and mechanistic factors such as variations in cardiac anatomy and physiology may play a role. This study compared ethnic differences in CT-assessed left ventricular (LV) mass, coronary anatomy and non-invasive fractional flow reserve (FFRCT). Methods Three-hundred symptomatic patients (age 59 ± 7.9, male 51%) underwent clinically-mandated CT-coronary-angiography (CTA) were matched for age, gender, BMI and diabetes (100 each ethnicity). Assessment of coronary stenosis, luminal dimensions and vessel dominance was performed by independent observers. LV mass, coronary luminal volume and FFRCT were quantified by blinded core-laboratory. A sub-analysis was performed on patients (n = 187) with normal/minimal disease (0–25% stenosis). Results Stenosis severity was comparable across ethnic groups. EA demonstrated less left-dominant circulation (2%) compared with SA (8.2%) and Caucasians (10.1%). SA compared with EA and Caucasians demonstrated smallest indexed LV mass, coronary luminal volumes and dimensions. EA compared with Caucasians had comparable indexed LV mass, coronary luminal dimensions and highest luminal volumes. The latter was driven by higher prevalence of right-dominance including larger and longer right posterior left ventricular artery. FFRCT in the left anterior descending artery (LAD) was lowest in SA (0.87) compared with EA (0.89; P = 0.009) and Caucasians (0.89; P Conclusion This single-centre study identified significant ethnic differences in CT-assessed LV mass, coronary anatomy and LAD FFRCT. These hypotheses generating results may provide a mechanistic explanation for ethnic differences in cardiovascular outcomes and require validation in larger cohorts.

Background An optimal aorto-coronary angiographic projection, characterized by an orthogonal visualization of the proximal coronary artery, is crucial for interventional success. We determined the distribution of optimal C-arm positions and assessed their feasibility by invasive coronary angiography. Methods Orthogonal aorto-coronary ostial angulations were determined in 310 CT data sets. In 100 patients undergoing subsequent invasive angiography, we assessed if the CT-predicted angulations were achievable by the C-arm system. If the predicted projection was not achievable due to mechanical constraints of the C-arm system, the most close, achievable angulation was determined. Patient characteristics were analyzed regarding the distribution of optimal angulations and its feasibility by the C-arm system. Results For the left ostium, CT revealed a mean angulation of LAO 23 ​± ​21°/cranial 25 ​± ​23° (90% of patients with a LAO/cranial angulation, 3% LAO/caudal, 4% RAO/cranial, 3% RAO/caudal) and were achievable by the C-arm system in 87% of patients. For the right ostium, the mean CT-predicted orthogonal angulation was LAO 36 ​± ​37°/cranial 36 ​± ​51° (84% LAO/cranial, 2% LAO/caudal, 14% RAO/caudal) and achievable by the C-arm system in 45% of patients. For the left ostium, a higher body weight was associated with a steeper LAO/cranial angulation being less feasible by the C-arm system due to mechanical constraints. Conclusions Orthogonal aorto-left coronary angulations show a relative narrow distribution predominately in LAO/cranial position whereas a wider range of angulations was found for the right coronary ostium. The feasibility of CT-predicted angulations by the C-arm system is more restricted for the right than the left coronary ostium.

We evaluated the diagnostic accuracy of a novel prototype for on-site determination of CT-based FFR (cFFR) on a standard personal computer (PC) compared to invasively measured FFR in patients with suspected coronary artery disease.A total of 91 vessels in 71 patients (mean age 65 ± 9 years) in whom coronary CT angiography had been performed due to suspicion of coronary artery disease, and who subsequently underwent invasive coronary angiography with FFR measurement were analyzed. For both cFFR and FFR, a threshold of ≤0.80 was used to indicate a hemodynamically relevant stenosis. The mean time needed to calculate cFFR was 12.4 ± 3.4 min. A very close correlation between cFFR and FFR could be shown (r = 0.85; p 0.0001) with Bland-Altman analysis showing moderate agreement between FFR and cFFR with mild systematic overestimation of FFR values in CT (mean difference 0.0049, 95% limits of agreement ±2SD -0.007 to 0.008). Compared to FFR, the sensitivity of cFFR to detect hemodynamically significant lesions was 91% (19/21, 95% CI: 70%-99%), specificity was 96% (67/70, 95% CI: 88%-99%), positive predictive value 86% (95% CI: 65%-97%) and negative predictive value was 97% (95% CI: 90%-100%) with an accuracy of 93%.cFFR obtained using an on-site algorithm implemented on a standard PC shows high diagnostic accuracy to detect lesions causing ischemia as compared to FFR. Importantly, the time needed for analysis is short which may be useful for improving clinical workflow.

The intent of CAD-RADS - Coronary Artery Disease Reporting and Data System is to create a standardized method to communicate findings of coronary CT angiography (coronary CTA) in order to facilitate decision-making regarding further patient management. The suggested CAD-RADS classification is applied on a per-patient basis and represents the highest-grade coronary artery lesion documented by coronary CTA. It ranges from CAD-RADS 0 (Zero) for the complete absence of stenosis and plaque to CAD-RADS 5 for the presence of at least one totally occluded coronary artery and should always be interpreted in conjunction with the impression found in the report. Specific recommendations are provided for further management of patients with stable or acute chest pain based on the CAD-RADS classification. The main goal of CAD-RADS is to standardize reporting of coronary CTA results and to facilitate communication of test results to referring physicians along with suggestions for subsequent patient management. In addition, CAD-RADS will provide a framework of standardization that may benefit education, research, peer-review and quality assurance with the potential to ultimately result in improved quality of care.

This expert consensus statement from the Society of Cardiovascular Computed Tomography (SCCT) provides an evidence synthesis on the use of computed tomography (CT) imaging for diagnosis and risk stratification of coronary artery disease in women. From large patient and population cohorts of asymptomatic women, detection of any coronary artery calcium that identifies females with a 10-year atherosclerotic cardiovascular disease risk of >7.5% may more effectively triage women who may benefit from pharmacologic therapy. In addition to accurate detection of obstructive coronary artery disease (CAD), CT angiography (CTA) identifies nonobstructive atherosclerotic plaque extent and composition which is otherwise not detected by alternative stress testing modalities. Moreover, CTA has superior risk stratification when compared to stress testing in symptomatic women with stable chest pain (or equivalent) symptoms. For the evaluation of symptomatic women both in the emergency department and the outpatient setting, there is abundant evidence from large observational registries and multi-center randomized trials, that CT imaging is an effective procedure. Although radiation doses are far less for CT when compared to nuclear imaging, radiation dose reduction strategies should be applied in all women undergoing CT imaging. Effective and appropriate use of CT imaging can provide the means for improved detection of at-risk women and thereby focus preventive management resulting in long-term risk reduction and improved clinical outcomes.

© 2015 Society of Cardiovascular Computed Tomography. Background: Coronary computed tomography angiography (coronary CTA) can prognosticate outcomes in patients without modifiable risk factors over medium term follow-up. This ability was driven by major adverse cardiovascular events (MACE). Objective: Determine if coronary CTA could discriminate risk of mortality with longer term follow-up. In addition we sought to determine the long-term relationship to MACE. Methods: From 12 centers, 1884 patients undergoing coronary CTA without prior coronary artery disease (CAD) or any modifiable CAD risk factors were identified. The presence of CAD was classified as none (0% stenosis), mild (1% to 49% stenosis) and obstructive (≥50% stenosis severity). The primary endpoint was all-cause mortality and the secondary endpoint was MACE. MACE was defined as the combination of death, nonfatal myocardial infarction, unstable angina, and late target vessel revascularization (>90 days). Results: Mean age was 55.6 ± 14.5 years. At mean 5.6 ± 1.3 years follow-up, 145(7.7%) deaths occurred. All-cause mortality demonstrated a dose-response relationship to the severity and number of coronary vessels exhibiting CAD. Increased mortality was observed for >1 segment non-obstructive CAD (hazard ratio [HR]:1.73; 95% confidence interval [CI]: 1.07-2.79; p = 0.025), obstructive 1&2 vessel CAD (HR: 1.70; 95% CI: 1.08-2.71; p = 0.023) and 3-vessel or left main CAD (HR: 2.87; 95% CI: 1.57-5.23; p = 0.001). Both obstructive CAD (HR: 6.63; 95% CI: 3.91-11.26; p < 0.001) and non-obstructive CAD (HR: 2.20; 95% CI: 1.31-3.67; p = 0.003) predicted MACE with increased hazard associated with increasing CAD severity; 5.60% in no CAD, 13.24% in non-obstructive and 36.28% in obstructive CAD, p < 0.001 for trend. Conclusions: In individuals being assessed for CAD with no modifiable risk factors, all-cause mortality in the long term (>5 years) was predicted by the presence of more than 1 segment of non-obstructive plaque, obstructive 1- or 2-vessel CAD and 3 vessel/left main CAD. Any CAD, whether non-obstructive or obstructive, predicted MACE over the same time period.

The 12th Annual Scientific Meeting of the SCCT, held from July 6 to July 9 in Washington, DC, was one of the largest to date with 724 attendants from 34 countries, 130 invited talks, 4 “Read with the Experts” sessions, 42 oral abstracts presented, 20 rapid fire posters and 164 poster presentations with the abstracts of all of these published in the JCCT. This article summarises the many themes and topics of presentation and discussion in this meeting, and the many technical advances that are likely to impact future clinical practice and feature in future meetings.

We investigated whether epicardial adipose tissue (EAT) volume and density are related to early atherosclerosis, plaque inflammation and major adverse cardiac events (MACE, cardiac death and myocardial infarction) in asymptomatic subjects.EAT volume and density were quantified from non-contrast cardiac CT in 456 asymptomatic individuals (age 60.3 ± 8.3; 68% with CCS0) from the prospective EISNER trial. EAT volume and density were examined in relation to coronary calcium score (CCS), inflammatory biomarkers and MACE.EAT volume was higher and EAT density lower in subjects with coronary calcium compared to subjects without [89 vs 74 cmEAT volume was higher and density lower in subjects with coronary calcium compared to subjects with CCS = 0, with similar EAT volume in CCS100 and CCS≥100. Lower EAT density and increased EAT volume were associated with coronary calcification, serum levels of plaque inflammatory markers and MACE, suggesting that dysfunctional EAT may be linked to early plaque formation and inflammation.

Coronary computed tomography angiography (coronary CTA) provides non-invasive evaluation of the coronary arteries with high precision for the detection of significant coronary artery disease (CAD).To investigate whether irregular heart rhythm including atrial fibrillation and premature beats during data acquisition influences (i) radiation and contrast media exposure, (ii) number of non-evaluable coronary segments and (iii) diagnostic impact of coronary CTA.Twelve tertiary care centers with ≥64 slice CT scanners and ≥5 years of experience with cardiovascular imaging participated in this registry. Between 2009 and 2014, 4339 examinations were analysed in patients who underwent clinically indicated coronary CTA for suspected CAD. Clinical and epidemiologic data were gathered from all patients. In addition, clinical presentation, heart rate and rhythm during the scan, Agatston score, radiation and contrast media exposure and the diagnostic impact of coronary CTA were systematically analysed.Of 4339 patients in total, 260 (6.0%) had irregular heart rhythm, whereas the remaining 4079 (94.0%) had stable sinus rhythm. Patients with irregular heart rhythm were older (63.2 ± 12.5yrs versus 58.6 ± 11.4yrs. p 0.001), exhibited a higher rate of pathologic stress tests before CTA (37.1% versus 26.1%, p 0.01) and higher heart rates during CTA compared to those with sinus rhythm (62.5 ± 11.6bpm versus 58.9 ± 8.5bpm, p 0.001). Both contrast media exposure and radiation exposure were significantly higher in patients with irregular heart rhythm (90 mL (95%CI = 80-110 mL) versus 80 mL (95%CI = 70-90 mL) and 6.2 mSv (95%CI = 2.5-11.7) versus 3.3 mSv (95%CI = 1.7-6.9), p 0.001 for both). Coronary CTA excluded significant CAD less frequently in patients with irregular heart rhythm (32.9% versus 44.8%, p 0.001). This was attributed to the higher rate of examinations with at least one non-diagnostic coronary segment in patients with irregular heart rhythm (10.8% versus 4.6%, p 0.001). Subsequent invasive angiography could be avoided in 47.2% of patients with irregular heart rhythm compared to 52.9% of patients with sinus rhythm (p = NS), whereas downstream stress testing was recommended in 3.2% of patients with irregular heart rhythm versus 4.0% of patients with sinus rhythm (p = NS).A significant number of patients scheduled for coronary CTA have irregular heart rhythm in a real-world clinical setting. In such patients, heart rate during coronary CTA is higher, possibly resulting in (i) higher radiation and contrast agent exposure and (ii) more frequent coronary CTA examinations with at least one non-diagnostic coronary artery segment. However, this does not seem to lead to increased downstream stress testing or subsequent invasive procedures.

Coronary artery disease (CAD) and aortic stenosis share pathophysiological mechanisms and risk factors. We evaluated the clinical utility of coronary computed tomography angiography (CTA) to identify CAD and revascularization requirement in patients with severe aortic stenosis considered for transcatheter aortic valve replacement (TAVR).Consecutive patients without known CAD underwent calcium scoring, CTA and invasive coronary angiography (ICA). A second-generation dual-source CT scanner was used. ICA-quantitative coronary angiography (QCA) served as reference standard. CAD was reported using a lenient threshold of ≥50% and a stricter threshold of ≥70% diameter reduction. Findings of ≥70% diameter reduction and of high-risk CAD were used to predict revascularization.The study included 140 patients [68 males; 82.3 (7.7) years]. CAD defined by the 50% threshold on ICA was found in 58/140 (41%) patients. CAD by the 70% threshold was found in 23/140 (16%) patients. High-risk CAD was found in 16/140 (11%) patients. CTA and ICA had similar odd-ratios of 3.22 (1.26-8.23) and 4.62 (1.64-13.05), respectively, in predicting revascularization. Forty-two/140 (30%) patients had400 Agatston calcium score, 98/140 (70%) patients had ≥400 calcium score. The diagnostic performance of CTA in the low calcium score group was better than the high calcium score group (AUC 0.81 vs. 0.63).CTA remained questionable to rule-out CAD as gatekeeper to ICA in TAVR candidates who had severe coronary calcifications. In patients with less severe coronary calcifications, accounting for 30% of participants in this study, CTA may play a clinical role.

Background Fractional flow reserve (FFR) is the standard of reference for assessing the hemodynamic significance of coronary stenoses in patients with stable coronary artery disease. Noninvasive FFR derived from coronary CT angiography (FFR CT ) is a promising new noninvasive method for assessing the physiologic significance of epicardial stenoses. The reproducibility of FFR CT has not yet been established. Objective The aim of this study was to evaluate the variation of repeated analyses of FFR CT per se and in the context of the reproducibility of repeated FFR measurements. Methods Coronary CT angiography and invasive coronary angiography with repeated FFR measurements were performed in 28 patients (58 vessels) with suspected stable coronary artery disease. Based on the coronary CT angiography data set, FFR CT analyses were performed twice by 2 independent blinded analysts. Results In 12 of 58 (21%) vessels FFR was ≤0.80. The standard deviation for the difference between first and second FFR CT analyses was 0.034 vs 0.033 for FFR repeated measurements ( P = .722). Limits of agreement were −0.06 to 0.08 for FFR CT and −0.07 to 0.06 for FFR. The coefficient of variation of FFR CT (CV FFRct ) was 3.4% (95% confidence interval [CI], 1.4%–4.6%) vs 2.7% (95% CI, 1.8%–3.3%) for FFR. In vessels with mean FFR ranging between 0.70 and 0.90 (n = 25), the difference between the first and second FFR CT analyses was 0.035 and FFR repeated measurements was 0.043 ( P = .357), whereas CV FFRct was 3.3% (95% CI, 1.5%–4.3%) and coefficient of variation for FFR was 3.6% (95% CI, 2.3%–4.6%). Conclusions The reproducibility of both repeated FFR CT analyses and repeated FFR measurements is high.

Dual-source CT offers accurate depiction of cardiac structures in children with congenital heart disease. For cardiac CT, optimal enhancement of the cardiovascular structures is essential. There is considerable controversy about the administration of contrast medium (CM) in infants and small children, with either a power injector or a manual (hand) injection.The aim of this study was to compare image quality with power injection of CM (study group) and manual injection (control group).Thirty-four patients (study group, 6.8 ± 9.6 months and control group, 4.6 ± 8.9 months, nonrandomized) underwent dual-source CT angiography of the chest using a prospective electrocardiography-triggered high-pitch spiral mode (pitch, 3.4; 80 kV). In the study group (17 patients), a power injector was used, and in the control group (17 patients, historical group), manual CM injection had been performed. To assess image quality, both subjective and objective parameters were evaluated independently by 2 experienced radiologists.Subjective overall image quality, signal-to-noise ratio, and contrast-to-noise ratio were significantly higher using power injection compared with manual injection (P.05). However, depiction of cardiovascular structures did not differ significantly between both groups in all evaluated regions except the superior vena cava and the coronary arteries.In infants and small children with congenital heart disease, both manual and power injector protocols allowed for diagnostic imaging of cardiac and extracardiac structures. However, image quality and vascular attenuation were superior using a power injector.

Background The diagnostic performance of multidetector row CT to detect coronary artery stenosis has been evaluated in numerous single-center studies, with only limited data from large cohorts with low-to-intermediate likelihood of coronary disease and in multicenter trials. The Multicenter Evaluation of Coronary Dual-Source CT Angiography in Patients with Intermediate Risk of Coronary Artery Stenoses (MEDIC) trial determines the accuracy of dual-source CT (DSCT) to identify persons with at least 1 coronary artery stenosis among patients with low-to-intermediate pretest likelihood of disease. Methods The MEDIC trial was designed as a prospective, multicenter, international trial to evaluate the diagnostic performance of DSCT for the detection of coronary artery stenosis compared with invasive coronary angiography. The study includes 8 sites in Germany, India, Mexico, the United States, and Denmark. The study population comprises patients referred for a diagnostic coronary angiogram because of suspected coronary artery disease with an intermediate pretest likelihood as determined by sex, age, and symptoms. All evaluations are performed by blinded core laboratory readers. Results The primary outcome of the MEDIC trial is the accuracy of DSCT to identify the presence of coronary artery stenoses with a luminal diameter narrowing of 50% or more on a per-vessel basis. Secondary outcome parameters include per-patient and per-segment diagnostic accuracy for 50% stenoses and accuracy to identify stenoses of 70% or more. Furthermore, secondary outcome parameters include the influence of heart rate, Agatston score, body weight, body mass index, image quality, and diagnostic confidence on the accuracy to detect coronary artery stenoses >50% on a per-vessel basis. Conclusion The results of the MEDIC trial will assess the clinical utility of coronary CT angiography in the evaluation of patients with intermediate pretest likelihood of coronary artery disease.

In transcatheter aortic valve replacement, prosthesis oversizing is essential to prevent paravalvular regurgitation. However, the estimated extent of oversizing strongly depends on the measurement used for annular sizing.The aim was to investigate the influence of geometrical parameters for calculation of relative oversizing in transcatheter aortic valve replacement, reported as percentage in relation to the native annulus size, to standardize reporting.Electrocardiogram-gated cardiac dual-source CT data of 130 consecutive patients with severe aortic stenosis (mean age, 81 ± 8 years; 56 men; mean aortic valve area, 0.67 ± 0.18 cm2) were included. Aortic annulus dimensions were quantified by means of planimetry that yielded area and perimeter at the level of the basal attachment points of the aortic cusps during systole. Area- and perimeter-derived diameters were calculated as DA = 2 × √(A/π) and DP = P/π. Hypothetical prosthesis sizing was based on DA (23-mm prosthesis for 19-22 mm; 26-mm prosthesis for 22-25 mm; 29-mm prosthesis for 25-28 mm). Relative oversizing for hypothetical prosthesis selection was calculated as percentage in relation to the native annulus size.Mean annulus area was 492.12 ± 94.9 mm2 and mean perimeter was 80.1 ± 7.6 mm. DP was significantly larger than DA (25.5 ± 2.4 mm vs 24.9 ± 2.4 mm; P.001). Mean maximum diameter was 28.1 ± 3.0 mm and mean minimal diameter was 22.8 ± 2.4 mm. Calculated eccentricity index [EI = 1 - minimal diameter/maximum diameter)] was 0.19 ± 0.06. Difference between DP and DA correlated significantly with EI (r = 0.67; P.001). Relative oversizing was 10.2% ± 3.8% and 21.6% ± 8.4% by DA and area, and 7.8% ± 3.9% by both DP and perimeter.For planimetric assessment of aortic annulus dimensions with CT, the percentage oversizing calculated strongly depends on the geometrical variable used for quantifying annular dimensions. Standardized nomenclature seems warranted for comparison of future studies.

Recently developed automated algorithms use the topogram and the corresponding attenuation information before coronary CT angiography (CTA) to allow for an individualized anatomic-based selection of tube current (mAs) and voltage (kV).The value of these algorithms in reducing the associated radiation exposure was evaluated.One hundred patients underwent coronary CTA with dual-source CT with prospectively electrocardiogram-triggered axial data acquisition. In all patients, tube parameters (current and voltage) were suggested by both an experienced investigator according to the patient's body mass index (BMI; calculated as weight divided by height squared; kg/m(2)) and by an automated software according to attenuation values of the initial topogram. The first 50 consecutive patients (group 1) underwent coronary CTA with dual-source CT with tube parameters suggested by the experienced investigator (BMI-based tube parameters), whereas in another 50 consecutive patients (group 2) CT data acquisition was performed with tube settings of the automated software. Subsequently, subjective image quality (4-point rating score from 0 = nondiagnostic to 3 = excellent image quality), image noise (SD of CT number within the aortic root), as well as signal- and contrast-to-noise ratios and mean effective radiation doses, were compared between both groups.Both groups showed comparable image quality parameters (group 1 vs 2: noise, 28.1 ± 6.0 HU vs 29.9 ± 5.4 HU, P = .12; signal-to-noise ratio, 16.4 ± 3.9 vs 16.8 ± 4.1, P = .54; contrast-to-noise ratio, 18.6 ± 4.1 vs 19.2 ± 4.3, P = .49; 4-point rating score, 2.8 ± 0.3 vs 2.9 ± 0.3, P = .81). Tube voltage, current, and mean effective radiation dose for groups 1 and 2 were 111 ± 12 kV and 108 ± 12 kV (P = .18), 361 ± 32 mAs and 320 ± 48 mAs (P.001), and 2.3 mSv (25th; 75th percentile, 1.5; 2.8 mSv) and 1.4 mSv (25th; 75th percentile, 1.1; 1.9 mSv) (P.001), respectively.Automated attenuation-based selections of individualized tube parameters are superior to BMI-based selections with expert oversight and show a potential for reduction of radiation exposure in coronary CTA, and image quality is maintained.

Different iterative reconstruction (IR) techniques compensate increased noise from lower tube current-time product settings, yet the differences between IR settings remain unclear.Aim of this study was to test whether different IR settings have a clinically relevant influence on image quality and on the diagnostic accuracy of low-dose CT angiography in patients with a stent.Forty-two patients with 73 coronary stents were prospectively enrolled. Data were acquired with dual-source CT, and images were reconstructed with standard filtered back projection (FBP) and raw data-based IR with different settings (I3, I4, I5). Quantitative parameters, including CT-attenuation, noise, signal-to-noise ratio, contrast-to-noise ratio, as well as the presence of in-stent stenosis50% were determined. All patients had invasive angiography as reference standard.Mean effective dose was 0.32 ± 0.02 mSv. Image noise decreased significantly compared with FBP (I3 = 29%; I4 = 38% and I5 = 45%), whereas signal-to-noise and contrast-to-noise ratios increased significantly (all IR settings P.01). Subjective image quality was superior with all IR settings (P.01). FBP sensitivity, specificity, positive predictive value, and negative predictive value were 83%, 71%, 36%, and 96% per stent compared with 100%, 76%, 44%, and 100%, respectively, in IR reconstructions independent of the IR setting applied.In low-dose coronary CT angiography, higher IR settings significantly improved subjective and objective image quality but had no effect on accuracy.

Effective radiation dose from a single coronary artery calcification CT scan can range from 0.8 to 10.5 mSv, depending on the protocol. Reducing the effective radiation dose to reasonable levels without affecting diagnostic image quality can result in substantial dose reduction in CT.We prospectively compared tube voltages of 120 and 100 kV in a low-dose CT acquisition protocol for measuring coronary artery calcified plaque with prospectively electrocardiogram (ECG)-triggered high-pitch spiral acquisition.In 150 consecutive patients, measurement of coronary artery calcified plaque was performed with prospectively ECG-triggered high-pitch spiral acquisition. Imaging was first done with tube voltage of 120 kV voltage and subsequently repeated with 100 kV and otherwise unchanged parameters. CT was performed with a dual-source CT system with 280 milliseconds of rotation time, 2 × 128 slices, pitch of 3.4, triggered at 60% of the R-R interval. Tube current for both protocols was set at 80 mAs. With the use of a medium sharp reconstruction kernel (Siemens B35f), cross-sectional images were reconstructed with 3.0-mm slice thickness and 1.5-mm increment. Agatston scores were determined per patient for both scan settings by 2 independent readers with the use of a standard threshold of 130 HU for calcium detection. In addition, the Agatston score was calculated with a previously proposed threshold of 147 HU for 100-kV acquisitions.Mean image noise was 20 ± 5 and 27 ± 7 for 120 and 100 kV, respectively (P0.0001). Mean dose length product was 24 ± 6 cm · cGy for the 120-kV protocol and 14 ± 4 cm · cGy for the 100-kV protocol, corresponding to average estimated effective doses of 0.3 and 0.2 mSv (P0.0001). Five patients were excluded from the analysis. In the remaining 145 patients, using the standard tube voltage of 120 kV, any coronary calcium was detected in 76 identical patients by both observers. In 75 of these patients, calcium was also identified by both observers in 100-kV data sets, whereas 1 patient was scored negative by 1 reader and was assigned an Agatston score of 0.7 (threshold, 130 HU) and 0.2 (threshold, 147 HU) by the other. Interobserver disagreement for assigning a patient a zero Agatston score was the same for both scan settings (each 4 patients). The mean Agatston scores for 120-kV and 100-kV (threshold, 147 HU) scans were 105 ± 245 (range, 0-1865) and 116 ± 261 (range, 0-1917), respectively (P0.0001). Bland-Altman analysis indicated a systematic overestimation of the Agatston score with tube voltage of 100 kV and threshold of 147 HU (mean difference, 11; 95% limits of agreement, 62 to -40). Similar results were observed for coronary calcium volume scores.High-pitch spiral acquisition allows coronary calcium scoring with effective doses below 0.5 mSv. The use of 100-kV tube voltage further reduces effective radiation dose compared with the standard of 120 kV; however, it leads to significant overestimation of the Agatston score when the standard threshold of 130 HU is used. Adjusting the threshold to 147 HU leads to a better agreement compared with standard 120 kV protocols yet with a remaining systematic bias toward overestimation of the Agatston score. For high-pitch spiral acquisition mode, effective radiation dose reduction when using a 100-kV setting is minimal compared with the standard 120-kV setting and may be considered nonsignificant in a clinical setting.

Background Recent guidelines for the workup of patients with chest pain and suspected coronary artery disease include coronary computed tomography angiography (CTA). However, its diagnostic value may be limited in patients with severe coronary calcification. Objective We investigated the relationship between the extent of coronary calcium and the ability of coronary CTA to rule out significant stenoses in a series of consecutive patients with suspected coronary artery disease. Methods 2614 consecutive patients with suspected coronary artery disease in whom coronary calcium scoring and coronary CTA had been performed by Dual Source CT were analyzed. The ability of coronary CTA to rule out coronary artery stenoses (fully evaluable coronary arteries and absence of any luminal stenosis >75%) was analyzed relative to the coronary calcium score. Results The median coronary calcium score was 12, with calcium present in 60.5% of all patients. Coronary CTA ruled out stenoses in 82% of patients, while in 18% of patients at least one stenosis was found or could not be excluded. The threshold above which coronary CTA permitted to rule out stenoses in less than 50% of patients was an “Agatston Score” of 287. This threshold was significantly lower for male patients (213 vs. 330), for patients with a heart rate >65 beats/min (157 vs. 317) and for patients with a body mass index ≥25 kg/m 2 (208 vs. 392). The evaluability of coronary arteries decreased with increasing amounts of calcium and differed significantly between heart rates ≤65 beats/min and >65 beats/min (p Conclusion In the largest patient series evaluated so far, we identified an “Agatston Score” of 287 to represent a threshold above which coronary CTA permits to rule out coronary artery stenoses in less than 50% of cases.

Coronary computed tomography angiography (CTA) plays an important role in the identification of coronary artery disease in low- to intermediate-risk patients. Even with a "restrictive" field of view, coronary CTA data sets will include visualization of structures adjacent to the heart, including the thoracic great vessels, pericardium, mediastinum, lungs, and bones. CT images enable detailed assessment of these structures, at times identifying a potential noncoronary cause of the patient's presenting symptom. The reported incidence of extracardiac findings on coronary CTA is as high as 53%–67%. Complete evaluation of the examination requires scrutiny of the soft tissues, lung tissues, and bones, both in the chest and adjacent abdomen. It is important to adjust the CT window display settings at various stages of the interpretation process to evaluate all potential extracardiac disease. Although in-depth radiology training would be required to correctly identify and interpret all anomalies, this article serves as an overview and guide to evaluation of the extracardiac structures included on a coronary CTA examination. Correct interpretation of extracardiac findings is critical because a false positive interpretation can lead to unnecessary testing and treatment that can be as harmful as a false negative interpretation. Most importantly, if the cardiac findings do not explain the patient's symptoms, an alternative cause should be specifically sought to appropriately manage the patient.

Background Coronary CT angiography allows visualization of the coronary arteries. However, motion artifact can impair delineation of the coronary artery lumen and detection of coronary artery stenoses. Objective We investigated the influence of heart rate and the segment of the cardiac cycle during which images are reconstructed on the occurrence of motion artifacts. Methods We evaluated coronary CT angiography datasets obtained by 64-slice dual-source CT in 100 consecutive patients. Data were reconstructed at 13 time instants during the cardiac cycle and evaluated for the presence of motion artifact. Results Mean heart rate was 66±14 beats/min. Overall, 98 of 100 patients had evaluable datasets. For heart rates ≤60 beats/min, optimal image quality was uniformly found during late diastole (100% of cases with evaluable image quality during a time window between 65% and 75% of the cardiac cycle). With increasing heart rates, images reconstructed during late systole more frequently provided best image quality. However, image reconstruction could not be restricted to a systolic time period. To achieve evaluable image quality in 95% of cases, data acquired between 25% and 75% of the cardiac cycle had to be available for patients with heart rates >60 beats/min. Conclusion Dual-source CT provides high image quality across a wide range of heart rates. Although data acquisition may be limited to diastole for patients with heart rates ≤60 beats/min, the availability of data acquired both during systole and diastole is necessary for patients with higher heart rates.

As populations in Western civilizations are aging, the prevalence of degenerative aortic valve stenosis is increasing. CT imaging provides information on aortic valve pathology in many ways: In nonenhanced scans, aortic valve calcification can be quantified accurately, which helps to understand the pathogenesis and progression of aortic sclerosis and stenosis. After contrast injection, CT allows excellent visualization of aortic valve structure and, through measurement of the aortic valve area, is capable to serve as a "backup method" for the assessment of aortic valve stenosis, especially if other imaging methods are difficult to interpret. Importantly, CT tends to overestimate aortic valve opening areas in comparison to transthoracic echocardiography, which relies on the continuity equation for quantifying aortic stenosis, based on flow velocities and the estimated area of the left ventricular outflow tract. It has recently been shown that the oval rather than round shape of the left ventricular outflow tract is the most likely factor behind this systematic difference between functional compared with anatomic assessment of aortic valve stenosis. In fact, the ability to provide superbly accurate anatomic imaging of the aortic valve and entire aortic root makes CT a uniquely useful tool for the planning of transcatheter aortic valve implantation. Hence, CT imaging spans a wide range of applications in aortic valve disease, from basic research to diagnosis and treatment planning. This review aims to summarize the current state of the art concerning imaging of the aortic valve by CT and the potential clinical applications.

The increasing use of coronary computed tomographyangiography(CCTA)requirestheestablishmentofstandardsmeant to ensure reliable practice methods and qualityoutcomes.TheSocietyofCardiovascularComputedTomog-raphy Guidelines Committeewas formed to develop recom-mendations for acquiring, interpreting, and reporting thesestudies in a standardized fashion. Indications and contrain-dicationsforspecificservicesorproceduresarenotincludedin the scope of these documents. These recommendationswere produced as an educational tool for practitioners toimprove the diagnostic care of patients, in the interest ofdevelopingsystematicstandardsofpracticeforCCTAbasedon the best available data or broad expert consensus. Due tothe highly variable nature of individual medical cases, anapproachtointerpretationorreportingthatdiffersfromtheseguidelinesmayrepresentanappropriatevariationbasedonalegitimate assessment of an individual patient’s needs.The Society of Cardiovascular Computed TomographyGuidelinesCommitteemakeseveryefforttoavoidanyactualorpotentialconflictsofinterestthatmightariseasaresultofan outside relationship or a personal interest of a member ofthe Guidelines Committee or either of its Writing Groups.Specifically, all members of the Guidelines Committee andof both Writing Groups are asked to provide disclosurestatementsofallsuchrelationshipsthatmightbeperceivedasrealorpotentialconflictsofinterestrelevanttothedocumenttopic. The relationships with industry information for Com-mittee members and Writing Group members are published

Background Multidetector computed tomography (MDCT) has recently emerged as a potential noninvasive alternative for high-resolution imaging of coronary arteries. Objective In this study, we evaluated 64-slice MDCT for detection, quantification, and characterization of atherosclerotic plaque burden in nonculprit lesions. Methods Data from 11 patients who underwent both MDCT and intravascular ultrasound (IVUS) for suspected coronary artery disease were collected, and a total of 17 coronary segments and 122 cross-sectional slices were analyzed by MDCT and IVUS. Coronary segments on MDCT were coregistered to IVUS, and each obtained slice was scored by 2 blinded observers for presence and type of plaque. Quantitative measurements included cross-sectional vessel area, lumen area, wall area, plaque volume, and plaque burden. Mean and standard deviation of Hounsfield units (HUs) were recorded for plaque when present. Results Overall sensitivity for plaque detection was 95.0%, and specificity, positive predictive value, negative predictive value were 88.7%, 89.1%, and 94.8%, respectively. Spearman's correlation coefficients were 0.85, 0.75, 0.70, 0.89, and 0.54 for cross-sectional vessel area, lumen area, wall area, plaque volume, and plaque burden, respectively. The interobserver variability for plaque burden and plaque volume measurements between readers on 64-MDCT was high at 32.7% and 30.4%, respectively. Combined noncalcified plaque had a mean MDCT density significantly different from that of calcified plaque. Soft and fibrous plaques were not able to be distinguished based on their HU values. Conclusion Sixty-four–slice MDCT had good correlation with IVUS but with high interobserver variability. Plaque characterization remains a challenge with present MDCT technology.

The recent evolution of multidetector computed tomography (CT) technology has substantially improved the ability of CT to visualize the heart and coronary arteries. After injection of contrast agent, relatively reliable imaging of the coronary arteries can be achieved, even though some restrictions are caused because the spatial and temporal resolutions are still somewhat limited. Several studies have shown that stenoses of the native coronary arteries can be detected with high sensitivity and specificity if image quality is adequate. More challenging situations include imaging of patients with stents and bypass grafts. Several clinical applications have been defined as “appropriate” and include the use of CT angiography in patients who have symptoms but who cannot exercise or who have an uninterpretable stress test result, or in patients with acute chest pain of intermediate likelihood for coronary artery disease but lack of electrocardiographic changes or myocardial enzyme elevations. It can be expected that further improvement of CT technology will help to more firmly establish the clinical role of CT coronary angiography and to explore further applications of this technique.

Epicardial adipose tissue (EAT) volume is associated with plaque formation and cardiovascular event risk, its density may reflect tissue composition and metabolic activity.Global and regional associations between EAT volume and density, ischemia and coronary calcium were investigated using a novel automatic quantitative measurement software.71 patients with an intermediate pre-test probability for coronary artery disease and inducible ischemia by SPECT were matched to two same-gender controls (total of 213 patients, 90% male, age 60 ± 10 years). Non-contrast CT for assessment of EAT volume, density (in Hounsfield Unit [HU]) and coronary calcium score (CCS) was performed.Global EAT volume was significantly increased in ischemic patients compared to controls (96 ± 49 vs. 82 ± 36 cm(3), p = 0.04), density showed no significant difference (-75.6 ± 4.3 vs. -75.1 ± 4.1HU, p = 0.63). EAT volume and density differed significantly between coronary territories (LAD: 37 ± 18 cm(3), -77.8 ± 4.5HU; LCx: 16 ± 9 cm(3), -73.9 ± 4.1HU; RCA: 36 ± 17 cm(3), -71.7 ± 4.8HU, p 0.001). For regional ischemia, only LCx territory showed a significantly higher EAT volume (18 ± 8 vs. 16 ± 9 cm(3), p = 0.048). Multivariable logistic regression revealed a significant association with ischemia for EAT volume (OR 2.09 (1.0; 4.3), p = 0.049) and CCS (OR 1.43 (1.1; 1.9), p = 0.006). EAT volume significantly improved discrimination of ischemia over CCS (Integrated Discrimination Improvement: 3.5%, 95%CI: 1.1-6.1%, p = 0.004). Hypertension was the only risk factor significantly influencing EAT volume and density (98 ± 48 vs. 78 ± 31 cm(3), p = 0.002, -76.0 ± 4.1 vs. -74.5 ± 4.1 HU, p = 0.01).EAT volume is associated with myocardial ischemia and improves the discriminative power for independent ischemia prediction over CCS. In hypertensive patients, EAT is characterized by lower density and higher volumes.

Background When coronary calcium scoring is performed in patients with suspected coronary artery disease, a separate noncontrast scan is acquired before contrast-enhanced coronary CT angiography (CTA). Objective Our aim was to develop and validate an automated method for calculating the coronary calcium score (CCS) from coronary CTA. Methods We analyzed coronary CTA and noncontrast CT data sets of 84 patients (Agatston score >0). The CCS on noncontrast CT was measured using commercial methods. Coronary calcium volume was measured on coronary CTA using an automated standardized method with scan-specific calcium thresholds. Data sets were split into derivation (n = 40) and validation groups (n = 44). To calculate the CCS on coronary CTA, a conversion factor between calcium scores measured in noncontrast CT and the calcium volume measured on coronary CTA was derived by linear regression. Results In the validation group, the median calculated CCS derived from CTA was 277 and 244 on noncontrast images ( P = .12). This CCS showed an excellent correlation with the CCS from noncontrast images (Pearson, r = 0.95). In the validation group, 39 of 44 patients (88.6%) were classified into the same standard category (1–10, 11–100, 101–400, or >400) with an excellent agreement (weighted κ of 0.87). Conclusion CCSs can be accurately measured from contrast-enhanced coronary CTA by using an automated, standardized method, obviating the need for a noncontrast scan.

Background Impaired myocardial flow reserve (MFR) is a marker of coronary vascular dysfunction with prognostic significance. Objectives We aimed to investigate the relationship between epicardial fat volume (EFV) measured from noncontrast CT and impaired MFR derived from rest-stress Rb-82 positron emission tomography (PET). Methods We retrospectively studied 85 consecutive patients without known coronary artery disease who underwent rest-stress Rb-82 myocardial PET/CT and were subsequently referred for invasive coronary angiography. EFV was computed from noncontrast CT by validated software and indexed to body surface area (EFVi, cm 3 /m 2 ). Global stress and rest MFR were automatically derived from PET. Patient age, sex, cardiovascular risk factors, coronary calcium score (CCS), and EFVi were combined by boosted ensemble machine learning algorithm into a novel composite risk score, using 10-fold cross-validation, to predict impaired global MFR (MFR ≤2.0) by PET. Results Patients with impaired MFR (44 of 85; 52%) were older (71 vs 65 years; P = .03) and had higher frequency of CCS (≥400; P = .02) with significantly higher EFVi (63.1 ± 20.4 vs 51.3 ± 14.1 cm 3 /m 2 ; P = .003). On multivariate logistic regression (with age, sex, number of risk factors, CCS, and EFVi), EFVi was the only independent predictor of impaired MFR (odds ratio, 7.39; P = .02). The machine learning composite risk score significantly improved risk reclassification of impaired MFR compared to CCS or EFVi alone (integrated discrimination improvement = 0.19; P = .007 and IDI = 0.22; P = .002, respectively). Conclusions Increased EFVi and composite risk score combining EFVi and CCS significantly improve identification of impaired global MFR by PET.

Pericoronary adipose tissue (PCAT) can promote atherosclerosis. Metabolically active and inactive PCAT may display different CT densities. However, CT density could be influenced by partial volume effects and image interpolation.To investigate whether PCAT density values in CT displays differences that are larger than those attributable to interpolation and partial volume effects, which would manifest themselves through the relationship between PCAT density and distance from the contrast-enhanced coronary lumen.PCAT density analysis was performed (417 non-atherosclerotic segments, 63 patients) using dual-source CT with a threshold-based measurement method. Changes in PCAT density values depending on distance from the contrast-enhanced coronary lumen and the influence of cardiovascular risk profile were analyzed.Mean PCAT density was -78.1 ± 5.6 HU. PCAT density decreased from proximal to distal segments in the LAD (-78.0 ± 7.3 vs. -82.4 ± 7.7 HU; p 0.001). PCAT density was higher close to the lumen compared to more peripheral locations (-76.0 ± 6.7 vs. -78.5 ± 5.4 HU; p 0.001). Decreasing PCAT density was significantly associated with higher epicardial adipose tissue (EAT) volume and body mass index. There was a trend of lower PCAT values with a family history of coronary artery disease.CT-measured attenuation of PCAT is influenced by EAT volume and body mass index. A decrease of PCAT attenuation with increasing distance from the vessel and from proximal to distal segments may suggest variations in CT density of PCAT due to partial volume effects and image interpolation rather than solely due to differences in tissue composition or metabolic activity.

Low tube voltage reduces radiation exposure in coronary CT angiography (CTA). Using 70 kVp tube potential has so far not been possible because CT systems were unable to provide sufficiently high tube current with low voltage.We evaluated feasibility, image quality (IQ), and radiation dose of coronary CTA using a third-generation dual-source CT system capable of producing 450 mAs tube current at 70 kVp tube voltage.Coronary CTA was performed in 26 consecutive patients with suspected coronary artery disease, selected for body weight100 kg and heart rate60 beats/min. High-pitch spiral acquisition was used. Filtered back projection (FBP) and iterative reconstruction (IR) algorithms were applied. IQ was assessed using a 4-point rating scale (1 = excellent, 4 = nondiagnostic) and objective parameters.Mean age was 62 ± 9 years (46% males; mean body mass index, 27.7 ± 3.8 kg/m(2); mean heart rate, 54 ± 5 beats/min). Mean dose-length product was 20.6 ± 1.9 mGy × cm; mean estimated effective radiation dose was 0.3 ± 0.03 mSv. Diagnostic IQ was found in 365 of 367 (FBP) and 366 of 367 (IR) segments (P nonsignificant). IQ was rated "excellent" in 53% (FBP) and 86% (IR) segments (P = .001) and "nondiagnostic" in 2 (FBP) and 1 segment (IR) (P nonsignificant). Mean IQ score was lesser in FBP vs IR (1.5 ± 0.4 vs 1.1 ± 0.2; P.001). Image noise was lower in IR vs FBP (60 ± 10 HU vs 74 ± 8 HU; P.001).In patients100 kg and with a regular heart rate60 beats/min, third-generation dual-source CT using high-pitch spiral acquisition and 70 kVp tube voltage is feasible and provides both robust IQ and very low radiation exposure.

Background Multidetector CT (MDCT) is performed to evaluate patients before transcatheter aortic valve replacement (TAVR). MDCT can uncover relevant nonvascular incidental findings. The use of venous phase imaging (VPI) in MDCT before TAVR has not been evaluated. Objective To evaluate the incidence of nonvascular findings in MDCT before TAVR with effect on the TAVR procedure and the value of VPI in this setting. Methods Sixty-four-slice MDCT angiography with VPI (100 mL contrast agent with 370-mg iopromide per mL) in 76 patients was retrospectively evaluated by 2 readers. Nonvascular findings were separately assessed on arterial and venous phase images and categorized in consensus as nonsignificant (no effect on TAVR), intermediate (further workup or surveillance necessary, no effect on TAVR), or significant (effect on TAVR). Radiation dose was recorded as dose-length product (DLP) and effective dose was calculated. Results A total of 169 findings were detected, of which 155 (91.7%) were nonsignificant, 13 (7.7%) were intermediate, and 1 (0.6%) was significant. TAVR was canceled in 1 patient (1.3%) because of suspected pancreatic cancer. No significant finding was seen on VPI only. Mean total DLP was 1137.9 mGy·cm (16.07 mSv) and the proportional mean DLP of VPI was 403 mGy·cm (6.85 mSv). Conclusion The incidence of nonvascular significant findings in MDCT before TAVR is low and VPI in our series did not add value. However, it may be considered in selected patients.

An 82-year-old patient developed right heart failure in the days after surgical aortic valve replacement. Coronary CT angiography showed a high-grade stenosis of the mid-right coronary artery. Adjacent suture material seen on noncontrast CT suggested that the lesion was related to surgical closure of the right atrial cannulation site. Invasive angiography confirmed the stenosis, and percutaneous intervention was successfully performed.

We evaluated the accuracy of commonly used thresholds for vessel area evaluation on coronary CT angiography (CTA) and assessed ability of CTA to image the adventitial border.We evaluated 137 paired (coronary CTA and intravascular ultrasound [IVUS]) coronary artery cross-sections in 30 patients. CTA analysis included measurements of external vessel border area defined at Hounsfield unit (HU) thresholds of 0 (presumed adventitia), 50, and 70 (presumed external elastic membrane [EEM]). IVUS analysis included measurements of lumen, EEM, and outer border of the highly echogenic area adjacent to EEM (presumed adventitia area).High correlation was found between CTA and IVUS measurements for EEM areas (R(2) = 0.65, P.001 and R(2) = 0.60, P.001 for CTA thresholds of 50 and 70 HU, respectively). CTA and IVUS measurements of adventitia areas were significantly correlated (R(2) = 0.74; P.001), with no significant difference between the 2 methods (20.2 ± 6.4 mm(2) vs 19.8 ± 6.4 mm(2), respectively; P = .278). Cross-sectional coronary lumen radiodensity on CTA images and plaque burden measured on IVUS significantly affected the accuracy of CTA in assessment of the EEM area but not the presumed adventitial area.We have demonstrated that use of a 50-HU threshold for vessel area determination by CTA led to its significant overestimation, whereas 70-HU threshold was close to that of EEM on IVUS. CTA may accurately delineate the coronary adventitial border by using a 0-HU threshold.

Coronary CTA allows characterization of non-calcified and calcified plaque and identification of high-risk plaque features.We aimed to quantitatively characterize and compare coronary plaque burden from CTA in patients with a first acute coronary syndrome (ACS) and controls with stable coronary artery disease.We retrospectively analyzed consecutive patients with non-ST-segment elevation myocardial infarction (NSTEMI) or unstable angina with a first ACS, who underwent CTA as part of their initial workup before invasive coronary angiography and age- and gender-matched controls with stable chest pain; controls also underwent CTA with subsequent invasive angiography (total n = 28). Culprit arteries were identified in ACS patients. Coronary arteries were analyzed by automated software to quantify calcified plaque (CP), noncalcified plaque (NCP), and low-density NCP (LD-NCP, attenuation30 Hounsfield units) volumes, and corresponding burden (plaque volume × 100%/vessel volume), stenosis, remodeling index, contrast density difference (maximum percent difference in attenuation/cross-sectional area from proximal cross-section), and plaque length.ACS patients had fewer lesions (median, 1), with higher total NCP and LD-NCP burdens (NCP: 57.4% vs 41.5%; LD-NCP: 12.5% vs 8%; P ≤ .04), higher maximal stenoses (85.6% vs 53.0%; P = .003) and contrast density differences (46.1 vs 16.3%; P.006). Per-patient CP burden was not different between ACS and controls. NCP and LD-NCP plaque burden was higher in culprit vs nonculprit arteries (NCP: 57.8% vs 9.5%; LD-NCP: 8.4% vs 0.6%; P ≤ .0003); CP was not significantly different. Culprit arteries had increased plaque lengths, remodeling indices, stenoses, and contrast density differences (46.1% vs 10.9%; P ≤ .001).Noninvasive quantitative coronary artery analysis identified several differences for ACS, both on per-patient and per-vessel basis, including increased NCP, LD-NCP burden, and contrast density difference.

Introduction Coronary CT angiography (CTA) is an established noninvasive method for visualization of coronary artery disease. However, coronary CTA lacks physiological information; thus, it does not permit differentiation of ischemia-causing lesions. Recent advances in computational fluid dynamic techniques applied to standard coronary CTA images allow for computation of fractional flow reserve (FFR), a measure of lesion-specific ischemia. The diagnostic performance of computed FFR (FFR CT ) compared with invasively measured FFR is not yet fully established. Methods/Design HeartFlowNXT (HeartFlow analysis of coronary blood flow using coronary CT angiography: NeXt sTeps) is a prospective, international, multicenter study designed to evaluate the diagnostic performance of FFR CT for the detection and exclusion of flow-limiting obstructive coronary stenoses, as defined by invasively measured FFR as the reference standard. FFR values ≤0.80 will be considered to be ischemia causing. All subjects (N = 270; 10 investigative sites) will undergo coronary CTA (single- or dual-source CT scanners with a minimum of 64 slices) and invasive coronary angiography with FFR. Patients with insufficient quality of coronary CTA will be excluded. Blinded core laboratory interpretation will be performed for FFR CT , invasive coronary angiography, and FFR. Stenosis severity by coronary CTA will be evaluated by the investigative site in addition to a blinded core laboratory interpretation. The primary objective of the study is to determine the diagnostic performance of FFR CT compared with coronary CTA alone to noninvasively determine the presence of hemodynamically significant coronary lesions. The secondary end point comprises assessment of diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of FFR CT .

Computed tomography (CT) plays an important role in the workup of patients who are candidates for implantation of a catheter-based aortic valve, a procedure referred to as transcatheter aortic valve implantation (TAVI) or transcatheter aortic valve replacement (TAVR). Contrast-enhanced CT imaging provides information on the suitability of the peripheral access vessels to accommodate the relatively large sheaths necessary to introduce the prosthesis. CT imaging also provides accurate dimensions of the ascending aorta, aortic root, and aortic annulus which are of importance for prosthesis sizing, and initial data indicate that compared with echocardiographic sizing, CT-based sizing of the prosthesis may lead to better results for postprocedural aortic valve regurgitation. Finally, CT permits one to predict appropriate fluoroscopic projections which are oriented orthogonal to the aortic valve plane. This consensus document provides recommendations about the use of CT imaging in patients scheduled for TAVR/TAVI, including data acquisition, interpretation, and reporting.

In transcatheter aortic valve implantation (TAVI), optimal selection of fluoroscopic projections that permit orthogonal visualization of the aortic valve plane is important but may be difficult to achieve.We developed and validated a simple method to predict suitable fluoroscopic projections on the basis of cardiac CT datasets.In 75 consecutive patients that underwent TAVI, angulations in which a 35-mm thick maximum intensity projection would render all aortic valve calcium into 1 plane were determined by manual interaction with contrast-enhanced dual-source CT datasets. TAVI operators used the predicted angulation for the first aortic angiogram and performed additional aortic angiograms if no satisfactory view of the aortic valve plane was obtained. Predicted angulations were compared with the angulation used for valve implantation. Radiation exposure and contrast use was compared between patients with accurate prediction of fluoroscopic angulations by CT and patients in whom CT failed to predict a suitable view.The mean difference between the predicted angulation according to CT and the angulation used for implantation was 3 ± 6 degrees. CT predicted a suitable angulation (5-degree deviation) in 63 of 75 cases (84%). The mean number of aortic angiograms acquired in patients with correct prediction (1.02 ± 0.1) was significantly lower than in patients with incorrect prediction of the implantation angle by CT (3.0 ± 1.7; P0.001). Contrast agent required for the entire TAVI procedure was lower in patients with correct prediction (72 ± 36 mL vs 106 ± 39 mL; P = 0.001).CT permits prediction of suitable angulations for TAVI in most cases.