Performance Of Coronary Computed Tomography Angiography Research Articles

SECT and DECT coronarography

Coronary artery disease is an atherosclerotic disease of the coronary arteries with consequent development of ischemic heart disease and is one of the leading causes of death in developed and developing countries. The “golden” standard in the diagnosis of coronary disease is invasive coronarography, but with the development of coronary CT angiography, a sub-millimetre precise assessment of the anatomy of coronary arteries and heart has been made possible. While in the earlier stages, SECT devices were used for the needs of coronary CT angiography with synchronization with the ECG, the development of DECT devices enabled a significant rise in the performance of coronary CT angiography in the form of a better assessment of anatomy and stenoses of the coronary arteries caused by plaque, the possibility of assessing heart perfusion, obtaining an image with a minimal amount of artifacts, a smaller amount of applied iodine contrast agent, better characterization of the atherosclerotic plaque and its components, and all of the above with a lower radiation dose for the patient. While most of the conducted research speaks in favour of DECT devices versus SECT devices, the issue of inadequate utilization of the numerous possibilities of DECT devices in everyday clinical practice remains. The DECT technique can be implemented in several ways, depending on the structure of the DECT device (on the number of radiation sources, the structure/arrangement of detectors, or the use of filters), but the question of which type of DECT technique/device to use depends on the disadvantages and advantages of individual devices as well as on the final goal of diagnostic procedures.

Prognostic value of coronary CT angiography derived fractional flow reserve in patients with myocardial infarction

Abstract Funding Acknowledgements Type of funding sources: None. Introduction We sought to analyze whether invasive fractional flow reserve (FFRi) values of non-infarction related (non-IRA) lesions change over time in ST Elevation Myocardial Infarction (STEMI) patients and to evaluate the diagnostic performance of coronary CT angiography derived FFR (FFRCT) close to the index event for defining follow-up FFRi. Methods We prospectively enrolled 38 multi-vessel STEMI patients (mean age 61.6±9 years, mean body mass index 28.8±4.8 kg/m2, 23.1 % female) who underwent non-IRA baseline and follow-up FFRi measurement and during the 10-day period after the index event FFRCT measurement. Follow-up FFRi was performed in 45–60 days after the index event and staged percutaneous coronary intervention (PCI) was carried out if FFRi was ≤0.8 at follow-up. Results Mean FFRi values showed significant difference between baseline and follow-up (0.83±0.11 vs. 0.80±0.13 p = 0.04, respectively). Mean FFR-CT was 0.79±0.14. Stronger correlation and smaller mean bias was found between FFR-CT and follow-up FFRi (ρ=0.86, p<0.001, bias: 0.01) as compared with baseline FFRi (ρ=0.68, p<0.001, bias: 0.04). The overall accuracy was 94.7% with 100.0% sensitivity and 90.0% specificity for identifying lesions ≤0.8 on follow-up FFRi. Accuracy, sensitivity and specificity were 81.5%, 93.3% 73.9%, respectively for identifying lesions on baseline FFRi using FFR-CT. Conclusion Non-invasive assessment of FFR at hospital discharge after the acute event lead to a better diagnostic performance for the identification of hemodynamically relevant non-IRA lesions as compared with baseline FFRi. FFRCT might improve decision making by selecting the patients for staged PCI in patients with multi-vessel STEMI.

Incidental Coronary Artery Disease on Routine CT Coronary Angiography –An evidence-based approach

Atherosclerotic coronary artery disease is the leading cause of high morbidity and mortality across the globe [1]. Coronary CT angiography has emerged as a highly accurate non-invasive diagnostic modality for the diagnosis of atherosclerotic coronary artery disease [2]. Coronary CT angiography should be considered as an alternative to stress imaging technique for ruling out atherosclerotic coronary artery disease in patients with the lower range of intermediate pre-test probability for atherosclerotic stable coronary artery disease. However, coronary CT angiography is not recommended as a screening test in asymptomatic individuals without clinical suspicion of coronary artery disease. CT Coronary angiography has been performed routinely before many of the cardiac and non-cardiac procedures like TAVI, atrial fibrillation ablation prior to the organ transplantation. Many a times, advised by Family Physician or patients themselves for a routine screening for atherosclerotic coronary artery disease undergo CT coronary angiography. When incidental atherosclerotic coronary artery disease is found in such patients who do not have any typical or atypical symptom suggestive of coronary artery disease then question arises how to approach this patient as far as the risk estimation for future adverse cardiovascular event and prognostication is concerned. It also becomes imperative to decide the line of management for this patient. To answer these two pertinent questions, we need to understand the behavior and natural history of atherosclerosis & performance of CT coronary angiography in diagnosis and in predicting the prognosis of atherosclerotic disease.

Comparison of coronary CT angiography-based and invasive coronary angiography-based quantitative flow ratio for functional assessment of coronary stenosis: A multicenter retrospective analysis

BackgroundThe aim of this study was to evaluate the diagnostic performance of coronary CT angiography (CTA)-based quantitative flow ratio (QFR), namely CT-QFR, and compare it with invasive coronary angiography (ICA)-based Murray law QFR (μQFR), using fractional flow reserve (FFR) as the reference standard. MethodsPatients who underwent coronary CTA, ICA and pressure wire-based FFR assessment within two months were retrospectively analyzed. CT-QFR and μQFR were computed in blinded fashion and compared with FFR, all applying the same cut-off value of ≤0.80 to identify hemodynamically significant stenosis. ResultsPaired comparison between CT-QFR and μQFR was performed in 191 vessels from 167 patients. Average FFR was 0.81 ​± ​0.10 and 42.4% vessels had an FFR ≤0.80. CT-QFR had a slightly lower correlation with FFR compared with μQFR, although statistically non-significant (r ​= ​0.87 versus 0.90, p ​= ​0.110). The vessel-level diagnostic performance of CT-QFR was slightly lower but without statistical significance than μQFR (AUC ​= ​0.94 versus 0.97, difference: −0.03 [95%CI: −0.00-0.06], p ​= ​0.095), and substantially higher than diameter stenosis by CTA (AUC difference: 0.17 [95%CI: −0.10-0.23], p ​< ​0.001). The patient-level diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio for CT-QFR to identify FFR value ​≤ ​0.80 was 88%, 90%, 86%, 86%, 91%, 6.59 and 0.12, respectively. The diagnostic accuracy of CT-QFR was 84% in extensively calcified lesions, while in vessels with no or less calcification, CT-QFR showed a comparable diagnostic accuracy with μQFR (91% versus 92%, p ​= ​0.595). Intra- and inter-observer variability in CT-QFR analysis was −0.00 ​± ​0.04 and 0.00 ​± ​0.04, respectively. ConclusionsPerformance in diagnosis of hemodynamically significant coronary stenosis by CT-QFR was slightly lower but without statistical significance than μQFR, and substantially higher than CTA-derived diameter stenosis. Extensively calcified lesions reduced the diagnostic accuracy of CT-QFR.

Diagnostic Performance of CT-Derived Fractional Flow Reserve in Australian Patients Referred for Invasive Coronary Angiography

Non-invasive computed tomography (CT)-derived fractional flow reserve (FFRCT) is computed from standard coronary CT angiography (CTA) datasets and provides accurate vessel-specific ischaemia assessment of coronary artery disease (CAD). To date, the technique and its diagnostic performance has not been verified in the Australian clinical context. The aim of this study was to describe and compare the diagnostic performance of FFRCT and CTA for the detection of vessel-specific ischaemia as determined by invasive fractional flow reserve (FFR) in the Australian patient population. One-hundred-and-nine patients (219 vessels) referred for clinically mandated invasive angiography were retrospectively assessed. Each patient underwent research mandated CTA and FFRCT within 3 months of invasive angiography and invasive FFR assessment. Independent core laboratory assessments were made to determine visual CTA stenosis, FFRCT and invasive FFR values. FFRCT values were matched with the corresponding invasive FFR measurement taken at the given wire position. Visual CTA stenosis ≥50%, FFRCT values ≤0.8 and invasive FFR values ≤0.8 were considered significant for ischaemia. Per vessel accuracy, sensitivity, specificity, positive predictive value and negative predictive value of FFRCT were 80.4%, 80.0%, 80.6%, 64.9% and 90.0% respectively. Corresponding values for CTA were 75.1%, 87.1%, 69.2%, 58.1% and 91.7% respectively. In receiver operating characteristic curve analysis, FFRCT demonstrated superior area under the curve (AUC) compared with CTA in both per vessel (0.87 vs 0.77, p=0.004) and per patient analysis (0.86 vs 0.74, p=0.011). Per vessel AUC of combined CTA and FFRCT was superior to CTA alone (0.89 vs 0.77, p<0.0001). In this cohort of Australian patients, the diagnostic performance of FFRCT was found to be comparable to existing international literature, with demonstrated improvement in performance compared with CTA alone for the detection of vessel-specific ischaemia.

Impact of machine-learning-based coronary computed tomography angiography-derived fractional flow reserve on decision-making in patients with severe aortic stenosis undergoing transcatheter aortic valve replacement.

To evaluate feasibility and diagnostic performance of coronary CT angiography (CCTA)-derived fractional flow reserve (CT-FFR) for detection of significant coronary artery disease (CAD) and decision-making in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR) to potentially avoid additional pre-TAVR invasive coronary angiography (ICA). Consecutive patients with severe AS (n = 95, 78.6 ± 8.8 years, 53% female) undergoing pre-procedural TAVR-CT followed by ICA with quantitative coronary angiography were retrospectively analyzed. CCTA datasets were evaluated using CAD Reporting and Data System (CAD-RADS) classification. CT-FFR measurements were computed using an on-site machine-learning algorithm. A combined algorithm was developed for decision-making to determine if ICA is needed based on pre-TAVR CCTA: [1] all patients with CAD-RADS ≥ 4 are referred for ICA; [2] patients with CAD-RADS 2 and 3 are evaluated utilizing CT-FFR and sent to ICA if CT-FFR ≤ 0.80; [3] patients with CAD-RADS < 2 or CAD-RADS 2-3 and normal CT-FFR are not referred for ICA. Twelve patients (13%) had significant CAD (≥ 70% stenosis) on ICA and were treated with PCI. Twenty-eight patients (30%) showed CT-FFR ≤ 0.80 and 24 (86%) of those were reported to have a maximum stenosis ≥ 50% during ICA. Using the proposed algorithm, significant CAD could be identified with a sensitivity, specificity, and positive and negative predictive value of 100%, 78%, 40%, and 100%, respectively, potentially decreasing the number of necessary ICAs by 65 (68%). Combination of CT-FFR and CAD-RADS is able to identify significant CAD pre-TAVR and bears potential to significantly reduce the number of needed ICAs. • Coronary CT angiography-derived fractional flow reserve (CT-FFR) using machine learning together with the CAD Reporting and Data System (CAD-RADS) classification safely identifies significant coronary artery disease based on quantitative coronary angiography in patients prior to transcatheter aortic valve replacement. • The combination of CT-FFR and CAD-RADS enables decision-making and bears the potential to significantly reduce the number of needed invasive coronary angiographies.

Diagnostic Performance of CT FFR With a New Parameter Optimized Computational Fluid Dynamics Algorithm From the CT-FFR-CHINA Trial: Characteristic Analysis of Gray Zone Lesions and Misdiagnosed Lesions.

To assess the diagnostic performance of fractional flow reserve (FFR) derived from coronary computed tomography angiography (CTA) (CT-FFR) obtained by a new computational fluid dynamics (CFD) algorithm to detect ischemia, using FFR as a reference, and analyze the characteristics of “gray zone” and misdiagnosed lesions. This prospective multicenter clinical trial (NCT03692936, https://clinicaltrials.gov/) analyzed 317 patients with coronary stenosis between 30 and 90% in 366 vessels from five centers undergoing CTA and FFR between November 2018 and March 2020. CT-FFR were obtained from a CFD algorithm (Heartcentury Co., Ltd., Beijing, China). Diagnostic performance of CT-FFR and CTA in detecting ischemia was assessed. Coronary atherosclerosis characteristics of gray zone and misdiagnosed lesions were analyzed. Per-vessel sensitivity, specificity and accuracy for CT-FFR and CTA were 89.9, 87.8, 88.8% and 89.3, 35.5, 60.4%, respectively. Accuracy of CT-FFR was 80.0% in gray zone lesions. In gray zone lesions, lumen area and diameter were significantly larger than lesions with FFR < 0.76 (both p < 0.001), lesion length, non-calcified and calcified plaque volume were all significantly higher than non-ischemic lesions (all p < 0.05). In gray zone lesions, Agatston score (OR = 1.009, p = 0.044) was the risk factor of false negative results of CT-FFR. In non-ischemia lesions, coronary stenosis >50% (OR = 2.684, p = 0.03) was the risk factor of false positive results. Lumen area (OR = 0.567, p = 0.02) and diameter (OR = 0.296, p = 0.03) had a significant negative effect on the risk of false positive results of CT-FFR. In conclusion, CT-FFR based on the new parameter-optimized CFD model provides better diagnostic performance for lesion-specific ischemia than CTA. For gray zone lesions, stenosis degree was less than those with FFR < 0.76, and plaque load was heavier than non-ischemic lesions.

Update for the Performance of CT Coronary Angiography - Evidence-Based Application and Technical Guidance According to Current Consensus Guidelines and Practical Advice from the Clinical Routine.

Coronary CT angiography (cCTA) is a class 1 recommendation in the current guidelines by the European Society of Cardiology (ESC) for excluding significant coronary artery stenosis. To achieve optimal image quality at a low radiation dose, the imaging physician may choose different acquisition modes. Therefore, the consensus guidelines by the Society of Cardiovascular Computed Tomography (SCCT) provide helpful guidance for this procedure. The article provides practical recommendations for the application and acquisition of cCTA based on the current literature and our own experience. According to current ESC guidelines, cCTA is recommended in symptomatic patients with a low or intermediate clinical likelihood for coronary artery disease. We recommend premedication with beta blockers and nitrates prior to CT acquisition under certain conditions even with the latest CT scanner generations. The most current CT scanners offer three possible scan modes for cCTA acquisition. Heart rate is the main factor for selecting the scan mode. Other factors may be coronary calcifications and body mass index (BMI). · CCTA is a valid method to exclude coronary artery disease in patients with a low to intermediate clinical likelihood.. · Even with the latest generation CT scanners, premedication with beta blockers and nitrates can improve image quality at low radiation exposure.. · Current CT scanners usually provide retrospective ECG gating and prospective ECG triggering. Dual-source scanners additionally provide a "high pitch" scan mode to scan the whole heart during one heartbeat, which may also be achieved using single-source scanners with broad detectors in some cases.. · Besides the available scanner technology, the choice of scan mode primarily depends on heart rate and heart rate variability (e. g., arrhythmia).. · Soschynski M, Hagar MT, Taron J et al. Update for the Performance of CT Coronary Angiography. Fortschr Röntgenstr 2022; 194: 613 - 624.

The Atherosclerotic Profile of a Young Symptomatic Population between 19 and 49 Years: Coronary Computed Tomography Angiography or Coronary Artery Calcium Score?

(1) Background: Whether coronary computed tomography angiography (CTA) or the coronary artery calcium score (CACS) should be used for diagnosis of coronary heart disease, is an open debate. The aim of our study was to compare the atherosclerotic profile by coronary CTA in a young symptomatic high-risk population (age, 19–49 years) in comparison with the coronary artery calcium score (CACS). (2) Methods: 1137 symptomatic high-risk patients between 19–49 years (mean age, 42.4 y) who underwent coronary CTA and CACS were stratified into six age groups. CTA-analysis included stenosis severity and high-risk-plaque criteria (3) Results: Atherosclerosis was more often detected based on CTA than based on CACS (45 vs. 27%; p < 0.001), 50% stenosis in 13.6% and high-risk plaque in 17.7%. Prevalence of atherosclerosis was low and not different between CACS and CTA in the youngest age groups (19–30 y: 5.2 and 6.4% and 30–35 y: 10.6 and 16%). In patients older than >35 years, the rate of atherosclerosis based on CTA increased (p = 0.004, OR: 2.8, 95%CI:1.45–5.89); and was higher by CTA as compared to CACS (34.9 vs. 16.7%; p < 0.001), with a superior performance of CTA. In patients older than 35 years, stenosis severity (p = 0.002) and >50% stenosis increased from 2.6 to 12.5% (p < 0.001). High-risk plaque prevalence increased from 6.4 to 26.5%. The distribution of high-risk plaque between CACS 0 and >0.1 AU was similar among all age groups, with an increasing proportion in CACS > 0.1 AU with age. A total of 24.9% of CACS 0 patients had coronary artery disease based on CTA, 4.4% > 50% stenosis and 11.5% had high-risk plaque. (4) Conclusions: In a symptomatic young high-risk population older than 35 years, CTA performed superior than CACS. In patients aged 19–35 years, the rate of atherosclerosis was similar and low based on both modalities. CACS 0 did not rule out coronary artery disease in a young high-risk population.

Combined cCTA and TAVR Planning for Ruling Out Significant CAD: Added Value of ML-Based CT-FFR

ObjectivesThe purpose of this study was to analyze the ability of machine-learning (ML)-based computed tomography (CT)-derived fractional flow reserve (CT-FFR) to further improve the diagnostic performance of coronary CT angiography (cCTA) for ruling out significant coronary artery disease (CAD) during pre-transcatheter aortic valve replacement (TAVR) evaluation in patients with a high pre-test probability for CAD. BackgroundCAD is a frequent comorbidity in patients undergoing TAVR. Current guidelines recommend its assessment before TAVR. If significant CAD can be excluded on cCTA, invasive coronary angiography (ICA) may be avoided. Although cCTA is a very sensitive test, it is limited by relatively low specificity and positive predictive value, particularly in high-risk patients. MethodsOverall, 460 patients (age 79.6 ± 7.4 years) undergoing pre-TAVR CT were included and examined with an electrocardiogram-gated CT scan of the heart and high-pitch scan of the vascular access route. Images were evaluated for significant CAD. Patients routinely underwent ICA (388/460), which was omitted at the discretion of the local Heart Team if CAD could be effectively ruled out on cCTA (72/460). CT examinations in which CAD could not be ruled out (CAD+) (n = 272) underwent additional ML-based CT-FFR. ResultsML-based CT-FFR was successfully performed in 79.4% (216/272) of all CAD+ patients and correctly reclassified 17 patients as CAD negative. CT-FFR was not feasible in 20.6% because of reduced image quality (37/56) or anatomic variants (19/56). Sensitivity, specificity, positive predictive value, and negative predictive value were 94.9%, 52.0%, 52.2%, and 94.9%, respectively. The additional evaluation with ML-based CT-FFR increased accuracy by Δ+3.4% (CAD+: Δ+6.0%) and raised the total number of examinations negative for CAD to 43.9% (202/460). ConclusionsML-based CT-FFR may further improve the diagnostic performance of cCTA by correctly reclassifying a considerable proportion of patients with morphological signs of obstructive CAD on cCTA during pre-TAVR evaluation. Thereby, CT-FFR has the potential to further reduce the need for ICA in this challenging elderly group of patients before TAVR.

Abstract 11490: Coronary Computed Tomography Angiography with Fractional Flow Reserve Outperforms Single-Photon Emission Tomography Myocardial Perfusion Imaging in the Observation Unit

Introduction: Coronary Computed Tomography Angiography (CCTA) and SPECT myocardial perfusion imaging (SPECT-MPI) are equally safe in evaluating patients presenting to the emergency department with acute chest pain. However, no study has compared the use of CCTA with Fractional Flow Reserve (FFR-CT) to SPECT-MPI in a chest pain observation unit (OU). We compared the performance of CCTA (with FFR-CT as needed) to SPECT-MPI for change in coronary artery disease (CAD) specific treatment (statins, antianginals, antiplatelets, and coronary revascularization) as well its impact on length of hospital stay (LOS). Methods: In 2020, our institution implemented an algorithm-based protocol in the OU to select patients appropriate for CCTA with explicit guidelines for management based on the results. We performed a retrospective analysis of 105 patients (52 SPECT-MPI patients from the period prior to initiation of the OU CCTA protocol who met criteria for CCTA, and 53 CCTA patients after CCTA protocol initiation). We performed two-tailed t-tests and chi-squared analyses to compare changes in treatment and LOS in both groups. Results: Patients in the CCTA group were younger (61 vs. 67 years, p=0.007), but there were no significant differences in CAD risk factors amongst the two groups. CCTA led to significant increase in statin, antianginal, and antiplatelet therapies, cardiac catheterization and revascularization within 6 months. There was no increase in LOS. Finally, CCTA did not increase acute kidney injury at follow up (Table 1). Conclusion: CCTA with FFR-CT significantly improved patient care by increasing appropriate preventative CAD treatment compared to SPECT-MPI while increasing the rate of revascularization without compromising length of stay or kidney function. In conclusion, protocol-based use of CCTA with FFR-CT is a more effective tool when compared to SPECT-MPI for chest pain patients admitted to the OU.

The atherosclerosis profile by coronary CTA compared to the coronary artery calcium score (CACS) in a young symptomatic high-risk population between 19 and 49 years

Abstract Background Whether the coronary artery calcium score (CACS) or coronary CTA should be used in young high-risk adults for screening of coronary artery disease (CAD), is an open debate and data sparse. Aims To evaluate the coronary atherosclerosis profile by coronary computed tomography angiography (CTA) in a young symptomatic high-risk population (age, 19–49 years) in comparison with the coronary artery calcium score (CACS). Methods and results 1137 symptomatic high-risk patients between 19–49 years (mean 42.4y; 33.2%females) with suspected CAD who underwent CTA and CACS were assigned into 6 age groups (19–30; 31–35; 36–40; 41–45; 46–47; 48–49y).CTA-analysis included stenosis severity (CADRADS) and high-risk-plaque (“HRP”) criteria. Atherosclerosis was more often detected by CTA than by CACS (45% vs. 27%; p&amp;lt;0.001), &amp;gt;50% stenosis in 13.6% and HRP in 17.7%. Prevalence of atherosclerosis was low and not different between CACS and CTA in the youngest (19–30y:5.2% and 6.4%; 30–35y:10.6% and 16%). Above &amp;gt;35 years, atherosclerosis detection by CTA increased (p=0.004, OR: 2.8, 95% CI: 1.45–5.89); and was higher by CTA as compared to CACS (34.9% vs 16.7%; p&amp;lt;0.001). CTA outperformed CACS among all higher age groups &amp;gt;35 years, with an increasing gap towards a superior performance of CTA along with age: Above 35 years, stenosis severity (CADRADS) (p=0.002) and &amp;gt;50% stenosis increased from 2.6% to 12.5% (p&amp;lt;0.001). The rate of HRP increased linearly with age from 6.4% to 26.5%.The distribution of HRP into CACS0 and CACS&amp;gt;0.1AU was similar among all age groups (CACS 0:45.1% had HRP), with an increasing proportion of HRP in CACS&amp;gt;0.1AU with age. 24.9% of CACS 0 patients had CAD by CTA, 4.4% &amp;gt;50% stenosis and 11.5% HRP. Conclusion Above 35 years of age, CTA outperforms CACS with an increasing power. Between 19 and 35 years, CACS 0 does not reliably rule out CAD and high-risk-plaque; hence for “noRISK100%safety”, CTA is superior.(#eachlifematters) Funding Acknowledgement Type of funding sources: None. 30 YOM diabetic, CACS 0 and HRP by CTAAtherosclerosis vs age: CACS vs CTA

Incremental improvement of diagnostic performance of coronary CT angiography for the assessment of coronary stenosis in the presence of calcium using a dual-layer spectral detector CT: validation by invasive coronary angiography.

To investigate value of spectral reconstructions for the quantification of coronary stenosis in the presence of calcified or partially calcified plaques using a dual-layer spectral detector CT (SDCT). Seventy-two consecutive patients were retrospectively enrolled. Conventional 120 kVp images, eight virtual monoenergetic images (VMI) (70 to 140 keV), the effective atomic number (Z effective) and iodine no water images were reconstructed. Invasive coronary angiography was used as the reference standard. Parallel and serial testing were used to assess the incremental diagnostic value of Z effective and iodine no water images to the best VMI series. 122 coronary lesions of 72 patients (49 men and 23 women; 63.7 ± 10.2 years) were enrolled in analysis. Reconstruction at 100 keV yielded optimal diagnostic performance, the sensitivity, specificity, PPV, NPV and diagnostic accuracy to identify stenosis ≥ 50% or ≥ 70% were 84%, 70%, 80%, 76%, 79% and 78%, 98%, 93%, 91%, 92%, respectively. A serial combination (100 keV VMI followed by Z effective images) resulted in an improved specificity (from 70 to 80%) with a moderate loss of sensitivity (81% from 84%) in identifying ≥ 50% stenosis (P = 0.021). For patients with high Agatston score, this combination could further reduce false positive cases and improve diagnostic accuracy. 100 keV VMI provide optimal diagnostic performance for the detection of coronary stenosis in the presence of calcified or partially calcified plaques using a dual-layer SDCT, with further improvements obtained with the combined use of Z effective images.

Functional assessment of coronary plaques using CT based hemodynamic simulations: Current status, technical principles and clinical value

AbstractIn recent years, coronary computed tomography angiography (CCTA) has emerged as an accurate and safe non-invasive imaging modality in terms of detecting and excluding coronary artery disease (CAD). In the latest European Society of Cardiology Guidelines CCTA received Class I recommendation for the evaluation of patients with stable chest pain with low to intermediate clinical likelihood of CAD. Despite its high negative predictive value, the diagnostic performance of CCTA is limited by the relatively low specificity, especially in patients with heavily calcified lesions. The discrepancy between the degree of stenosis and ischemia is well established based on both invasive and non-invasive tests. The rapid evolution of computational flow dynamics has allowed the simulation of CCTA derived fractional flow reserve (FFR-CT), which improves specificity by combining anatomic and functional information regarding coronary atherosclerosis. FFR-CT has been extensively validated against invasively measured FFR as the reference standard. Due to recent technological advancements FFR-CT values can also be calculated locally, without offsite processing. Wall shear stress (WSS) and axial plaque stress (APS) are additional key hemodynamic elements of atherosclerotic plaque characteristics, which can also be measured using CCTA images. Current evidence suggests that WSS and APS are important hemodynamic features of adverse coronary plaques. CCTA based hemodynamic calculations could therefore improve prognostication and the management of patients with stable CAD.

Influence of heart rate and coronary artery calcification on image quality and diagnostic performance of coronary CT angiography: comparison between 96-row detector dual source CT and 256-row multidetector CT.

CT-derived fractional flow reserve (FFRCT) and diagnostic accuracy rely on good image quality during coronary CT angiography (CCTA). To investigate whether heart rate (HR) and coronary artery calcium (CAC) score decrease image quality and diagnostic performance of two advanced CT scanners including 96-row detector dual source CT (DSCT) and 256-row multidetector CT (MDCT). First, 79 patients who underwent CCTA (42 with DSCT and 37 with MDCT) and invasive coronary angiography (ICA) are enrolled. Next, coronary segments with excellent image quality are evaluated and the percentage is calculated. Then, diagnostic accuracy in detecting significant diameter stenosis is presented with ICA as the reference standard. Compared with the DSCT, the percentage of coronary segments with excellent image quality is lower (P = 0.010) while diagnostic accuracy on per-segment level is improved (P = 0.037) using MDCT. CAC score≥400 is the only independent factor influencing the percentage of coronary segments with excellent image quality [odds ratio (OR): DSCT, 3.096 and MDCT, 1.982] and segmental diagnostic accuracy (OR: DSCT, 2.630 and MDCT, 2.336) for both scanners. HR≥70 bpm (OR: 5.506) is the independent factor influencing the percentage of coronary segments with excellent image quality with MDCT. During CCTA, CAC score≥400 still decreases the proportion of coronary segments with excellent image quality and diagnostic accuracy with advanced CT scanners. HR≥70 bpm is another factor causing image quality decreasing with MDCT.

Diagnostic Performance Of Coronary Ct Angiography Compared To Invasive Coronary Angiography In A Large Academic Practice

Introduction: Coronary CT angiography (CCTA) is increasingly used to assess coronary artery disease (CAD) and triage patients for invasive coronary angiography (ICA). Literature shows high negative predictive value, sensitivity, and accuracy of CCTA to detect stenosis using ICA as a gold standard, however analyses are usually done post-hoc with multi-reader agreement in a core lab setting and on a lower risk population. Data on CCTA performance compared to ICA in live clinical practice or with high risk patients are relatively sparse.

P7 The impact of coronary calcification on diagnostic performance of workstation CT derived fractional flow reserve - a multicentre experience

Abstract Background On-site workstation based computed tomography derived fractional flow reserve (CT-FFR) is an emerging method to assess the vessel specific ischaemia in coronary artery disease (CAD). The impact of coronary calcification on its diagnostic performance is unknown. Purpose To evaluate the impact of coronary calcification on the diagnostic performance of reduced-order CT-FFR at detecting vessel specific ischaemia. Methods This is a retrospective pooled analysis of 141 patients with suspected CAD enrolled from 3 global centres who underwent CT-coronary angiography (CTA), onsite CT-FFR and invasive FFR. Coronary calcification was assessed by Agatston score (AS). The diagnostic performance of CT-FFR (≤0.8) and CTA (≥50%) in evaluation of vessel specific ischaemia (FFR ≤ 0.8) was assessed across AS quartiles (Q1-4). A comparison of diagnostic performance of the low to mid AS (Q1 to Q3) versus high AS (Q4) was performed. Results Mean age and median AS was 65.8 ± 9.9 and 327.3 (interquartile range = 78.5 – 798.1). Diagnostic accuracy, sensitivity and specificity of CT-FFR for low-mid AS (0-798) and high AS (799-4019) were 77.4% vs 82.9%; 78.9% vs 94.7%; 68.8% vs 76.5% respectively with no statistical difference between the two groups. The AUC for ischaemia of CT-FFR in low to mid AS was comparable with AUC in the high AS (0.76 [95% CI: 0.66-0.86] vs 0.84 [0.69-0.99]; P = 0.397). The AUC for ischemia for CT-FFR in both low to mid AS and high AS was significantly higher than for CTA (0.76 [0.66-0.86] vs 0.57 [0.50-0.64]; P = 0.003 and 0.84 [0.69-0.99] vs 0.48 [0.38-0.57]; P &amp;lt; 0.001 respectively). Conclusion On-site workstation CT-FFR demonstrated consistently high diagnostic performance in patients with high AS. Its diagnostic performance was superior when compared with significant stenosis assessment on CTA across all spectrum of Agatston scores.

False-Negative Low Tube Voltage Coronary CT Angiography: High Intravascular Attenuation at Coronary CT Angiography Can Mask Calcified Plaques.

To determine the impact of low tube voltage coronary CT angiography on detection of subclinical atherosclerosis. Retrospective sampling of an emergency department coronary CT angiography registry was performed. All patients in the registry underwent a noncontrast coronary artery calcium (CAC) scoring scan at 120 kV before coronary CT angiography. The study sample (n = 264) constituted patients with subclinical atherosclerosis (Coronary Artery Disease Reporting and Data System™ [CAD-RADS] 1 or 2) randomly mixed one-to-one with patients without atherosclerosis (CAD-RADS 0). The patients with coronary CT angiography performed at 70-90 kV were considered the low tube voltage group (n = 159) and patients with coronary CT angiography performed at 100-120 kV were considered the standard tube voltage group (n = 105). The number of coronary plaques and overall CAD-RADS classification (per patient) were evaluated twice: initially, by reading coronary CT angiography alone, and then, by coronary CT angiography in combination with a CAC scan. Considering the combined reading (CT angiography plus CAC scan) as the reference standard, the performance of coronary CT angiography alone was assessed for plaque detection and appropriate CAD-RADS (per patient) classification. The comparisons were made between the low tube voltage and standard tube voltage groups by using a Fisher exact test and χ2 test for proportions and a Mann-Whitney test and Kruskal-Wallis test for means. In total, 455 plaques were identified in 118 patients (70 of 159 patients in the low tube voltage group; 48 of 105 in the standard tube voltage group). When reading coronary CT angiographic images alone, 97 of 455 (21%) plaques were missed that led to an incorrect CAD-RADS classification in 16 of 264 (6%) studies (interpreted as CAD-RADS 0 instead of CAD-RADS 1 or 2). Missed plaques were significantly more frequent in the low tube voltage group versus the standard tube voltage group (41% [85 of 206] vs 5% [12 of 249], respectively; P < .001). Incorrect CAD-RADS classification was also seen more commonly in the low tube voltage group (8.8% [14 of 159] vs 2% [two of 105]; P = .01), typically at low plaque burden (median CAC score, 1; range, 1-4). Calcified plaques that appeared isodense to luminal contrast material attenuation were seen more frequently in the low tube voltage group compared with the standard tube voltage group (20% [32 of 159] vs 7.6% [eight of 105], respectively; P = .005). Coronary artery plaques may be missed at low tube voltage coronary CT angiographic examination performed without a concomitant CAC scan.© RSNA, 2019Supplemental material is available for this article.See also the commentary by Truong in this issue.

P6171Role of myocardial mass for identifying FFR-verified ischemia and determining therapeutic strategy

Abstract Background Conventional noninvasive approach using coronary CT angiography (CTA) focusing on only coronary artery lesions remains mismatch in identifying functional ischemia and determining indication for coronary revascularization. Purpose We aimed to assess the usefulness of CT-verified myocardial mass for identifying FFR-verified myocardial ischemia and determining the indication of coronary revascularization after FFR examination. Methods We examined 244 vessels with intermediate stenoses (50 to 90% stenosis visually on CTA) in 216 patients (mean age 69.2±9.2, 166 men) who underwent both coronary CTA and invasive FFR. In addition to coronary stenosis severity and plaque characteristics on visual, minimal lumen diameter (MLD), minimal lumen area (MLA), plaque volume, the entire myocardial volume of the target vessel (MTV) and that exposed to ischemia (FFR ≤0.80) (myocardial volume of ischemia: MVI) were evaluated. Additionally, therapeutic strategy after FFR was recorded. Results Of 244 vessels, myocardial ischemia (FFR ≤0.80) was shown in 99 (40.6%). MTV was larger in the patients with FFR-verified ischemia than those without (53.3±19.2 vs. 41.5±21.6, P&lt;0.001); MLA, plaque burden (PB) and percentage of aggregated plaque volume (%APV) were also associated with ischemia. The area under the curves (AUCs) of MLA, PB, %APV, and MTV were 0.69, 0.67, 0.64, and 0.71, respectively. Addition of MTV to a model with coronary stenosis on visual, MLA, PB, and %APV improved C-index (from 0.72 to 0.79, P&lt;0.01), net reclassification improvement (NRI) (0.71, P&lt;0.01), and integrated discrimination improvement (IDI) (0.10, P&lt;0.01). Of 99 vessels with FFR ≤0.80, MVI was larger in the vessels with early revascularization after FFR than those without (38.8 vs. 29.1, P=0.01). Conclusions The measurement of myocardial mass improves the diagnostic performance of coronary CTA for the identification of coronary arteries with FFR-verified ischemia. Furthermore, it is associated with therapeutic strategy for the diseased vessels after FFR examination.

CT Perfusion Versus Coronary CT Angiography in Patients With Suspected In-Stent Restenosis or CAD Progression

ObjectivesThe goal of this study was to assess the diagnostic performance of coronary computed tomography angiography (CTA) alone, adenosine-stress myocardial perfusion assessed by computed tomography (CTP) alone, and coronary CTA + CTP by using a 16-cm Z-axis coverage scanner versus invasive coronary angiography (ICA) and fractional flow reserve (FFR) as the clinical standard. BackgroundDiagnostic performance of coronary CTA for in-stent restenosis detection is still challenging. Recently, CTP showed additional diagnostic power over coronary CTA in patients with suspected coronary artery disease. However, few data are available on CTP performance in patients with previous stent implantation. MethodsConsecutive stable patients with previous coronary stenting referred for ICA were enrolled. All patients underwent stress myocardial CTP and rest CTP + coronary CTA. Invasive FFR was performed during ICA when clinically indicated. The diagnostic rate and diagnostic accuracy of coronary CTA, CTP, and coronary CTA + CTP were evaluated in stent-, territory-, and patient-based analyses. ResultsIn the 150 enrolled patients (132 men; mean age 65.1 ± 9.1 years), the CTP diagnostic rate was significantly higher than that of coronary CTA in all analyses (territory based [96.7% vs. 91.1%; p < 0.0001] and patient based [96% vs. 68%; p < 0.0001]). When ICA was used as gold standard, CTP diagnostic accuracy was significantly higher than that of coronary CTA in all analyses (territory based [92.1% vs. 85.5%, p < 0.03] and patient based [86.7% vs. 76.7%, p < 0.03]). The concordant coronary CTA + CTP assessment exhibited the highest diagnostic accuracy values versus ICA (95.8% in the territory-based analysis). The diagnostic accuracy of CTP was significantly higher than that of coronary CTA (75% vs. 30.5%; p < 0.001). The radiation exposure of coronary CTA + CTP was 4.15 ± 1.5 mSv. ConclusionsIn patients with coronary stents, CTP significantly improved the diagnostic rate and accuracy of coronary CTA alone compared with both ICA and invasive FFR as gold standard.