Coronary Computed Tomography Angiography Studies Research Articles

Discrepancies between Coronary Artery Calcium Score and Coronary Artery Disease Severity in Computed Tomography Angiography Studies.

The aim of this paper is to demonstrate the difference in usefulness of the coronary artery calcium score (CACS) and the full assessment of the severity of coronary artery disease in coronary computed tomography angiography (CCTA) studies. The difference between the population risk of coronary artery disease (CAD) assessed by the CACS and the severity of CAD was demonstrated in images from two CCTA studies. The first image is from a patient with a CACS of 0 and significant coronary artery stenosis. In the native phase of CCTA examination, no calcified changes were detected in the topography of the coronary arteries. In the middle section of the left descending artery (LAD), at the level of the second diagonal branch (Dg2), a large non-calcified atherosclerotic plaque was visible. Mid-LAD stenosis was estimated to be approximately 70%. The second image features a patient with a high CACS but no significant coronary artery stenosis. The calcium score of individual coronary arteries calculated using the Agatston method was as follows: left main (LM) 0, LAD 403, left circumflex (LCx) 207.7, right coronary artery (RCA) 12. CACS was 622.7, representing a significant population risk of significant CAD. In the proximal and middle sections of the LAD, numerous calcified and mixed atherosclerotic plaques with positive remodeling were visible, causing stenosis of 25-50%. Similarly, in the proximal and middle sections of the LCx, numerous calcified and mixed atherosclerotic plaques with positive remodeling were visualized, causing stenoses of 25-50%. Calcified atherosclerotic plaques were found in the RCA, causing stenosis <25%. The entire CCTA image met CAD-RADS 2 (coronary artery disease reporting and data system) criteria. In summary, CACS may be applicable in population-based studies to assess the risk of significant CAD. In the evaluation of individual patients, a comprehensive assessment of CAD severity based on the angiographic phase of the CCTA examination should be used.

NoiseNet, a fully automatic noise assessment tool that can identify non-diagnostic CCTA examinations

Image noise and vascular attenuation are important factors affecting image quality and diagnostic accuracy of coronary computed tomography angiography (CCTA). The aim of this study was to develop an algorithm that automatically performs noise and attenuation measurements in CCTA and to evaluate the ability of the algorithm to identify non-diagnostic examinations. The algorithm, “NoiseNet”, was trained and tested on 244 CCTA studies from the Swedish CArdioPulmonary BioImage Study. The model is a 3D U-Net that automatically segments the aortic root and measures attenuation (Hounsfield Units, HU), noise (standard deviation of HU, HUsd) and signal-to-noise ratio (SNR, HU/HUsd) in the aortic lumen, close to the left coronary ostium. NoiseNet was then applied to 529 CCTA studies previously categorized into three subgroups: fully diagnostic, diagnostic with excluded parts and non-diagnostic. There was excellent correlation between NoiseNet and manual measurements of noise (r = 0.948; p < 0.001) and SNR (r = 0.948; <0.001). There was a significant difference in noise levels between the image quality subgroups: fully diagnostic 33.1 (29.8–37.9); diagnostic with excluded parts 36.1 (31.5–40.3) and non-diagnostic 42.1 (35.2–47.7; p < 0.001). Corresponding values for SNR were 16.1 (14.0–18.0); 14.0 (12.4–16.2) and 11.1 (9.6–14.0; p < 0.001). ROC analysis for prediction of a non-diagnostic study showed an AUC for noise of 0.73 (CI 0.64–0.83) and for SNR of 0.80 (CI 0.71–0.89). In conclusion, NoiseNet can perform noise and SNR measurements with high accuracy. Noise and SNR impact image quality and automatic measurements may be used to identify CCTA studies with low image quality.

Atherosclerosis evaluation and cardiovascular risk estimation using coronary computed tomography angiography.

Clinical risk scores based on traditional risk factors of atherosclerosis correlate imprecisely to an individual's complex pathophysiological predisposition to atherosclerosis and provide limited accuracy for predicting major adverse cardiovascular events (MACE). Over the past two decades, computed tomography scanners and techniques for coronary computed tomography angiography (CCTA) analysis have substantially improved, enabling more precise atherosclerotic plaque quantification and characterization. The accuracy of CCTA for quantifying stenosis and atherosclerosis has been validated in numerous multicentre studies and has shown consistent incremental prognostic value for MACE over the clinical risk spectrum in different populations. Serial CCTA studies have advanced our understanding of vascular biology and atherosclerotic disease progression. The direct disease visualization of CCTA has the potential to be used synergistically with indirect markers of risk to significantly improve prevention of MACE, pending large-scale randomized evaluation.

Rationale and design of the CONFIRM2 (Quantitative COroNary CT Angiography Evaluation For Evaluation of Clinical Outcomes: An InteRnational, Multicenter Registry) study

BackgroundIn the last 15 years, large registries and several randomized clinical trials have demonstrated the diagnostic and prognostic value of coronary computed tomography angiography (CCTA). Advances in CT scanner technology and developments of analytic tools now enable accurate quantification of coronary artery disease (CAD), including total coronary plaque volume and low attenuation plaque volume. The primary aim of CONFIRM2, (Quantitative COroNary CT Angiography Evaluation For Evaluation of Clinical Outcomes: An InteRnational, Multicenter Registry) is to perform comprehensive quantification of CCTA findings, including coronary, non-coronary cardiac, non-cardiac vascular, non-cardiac findings, and relate them to clinical variables and cardiovascular clinical outcomes. DesignCONFIRM2 is a multicenter, international observational cohort study designed to evaluate multidimensional associations between quantitative phenotype of cardiovascular disease and future adverse clinical outcomes in subjects undergoing clinically indicated CCTA. The targeted population is heterogenous and includes patients undergoing CCTA for atherosclerotic evaluation, valvular heart disease, congenital heart disease or pre-procedural evaluation. Automated software will be utilized for quantification of coronary plaque, stenosis, vascular morphology and cardiac structures for rapid and reproducible tissue characterization. Up to 30,000 patients will be included from up to 50 international multi-continental clinical CCTA sites and followed for 3–4 years. SummaryCONFIRM2 is one of the largest CCTA studies to establish the clinical value of a multiparametric approach to quantify the phenotype of cardiovascular disease by CCTA using automated imaging solutions.

Coronary computed tomography in emergencies: The importance of the radiologist’s experience

IntroductionIncorporating coronary computed tomography angiography (CTA) in the hospital workup for suspected acute coronary syndrome requires appropriate skills for interpreting this imaging test. Radiologists’ skills can affect the interobserver agreement in evaluating these studies. ObjectiveTo determine the interobserver agreement according to radiologists’ experience in the interpretation of coronary CTA studies done in patients who present at the emergency department with acute chest pain and low-to-intermediate probability of acute coronary syndrome. Materials and methodsWe studied the interobserver agreement in the urgent evaluation of coronary CTA studies in which CAD-RADS was used to register the findings. We created pairs of observers among a total of 8 assessors (4 attending radiologists and 4 radiology residents). We used the kappa coefficient to estimate the overall concordance and the concordance between subgroups according to their experience. ResultsThe agreement was substantial between experienced radiologists and residents (k=0.627; 95%CI: 0.436–0.826) as well as between all the pairs of observers (k=0.661; 95%CI: 0.506–0.823) for all the CAD-RADS together. The degree of agreement within the group of experienced radiologists was greater than that within the group of residents in all the analyses. The agreement was excellent for the overall CAD-RADS (k=0.950; 95% CI: 0.896–1) and for CAD-RADS ≥ 4 (k=1); the agreement was lower for CAD-RADS ≥ 3 (k=0.754; 95% CI: 0.246–1.255). The agreement for the residents for these categories was k=0.623, k=0.596, and k=0.473, respectively. ConclusionThe agreement among attending radiologists regarding the assessment of urgent coronary CTA studies is excellent. The agreement is lower when residents are paired with attending radiologists. These findings should be taken into consideration when implementing coronary CTA in emergency departments and in the organisation of radiological staff for interpreting and reporting this imaging test.

Towards universal comparability of pericoronary adipose tissue attenuation: a coronary computed tomography angiography phantom study

ObjectivesDifferent computed tomography (CT) scanners, variations in acquisition protocols, and technical parameters employed for image reconstruction may introduce bias in the analysis of pericoronary adipose tissue (PCAT) attenuation derived from coronary computed tomography angiography (CCTA). Therefore, the aim of this study was to establish the effect of tube voltage, measured as kilovoltage peak (kVp), and iterative reconstruction on PCAT mean attenuation (PCATMA).MethodsTwelve healthy ex vivo porcine hearts were injected with iodine-enriched agar-agar to allow for ex vivo CCTA imaging on a 256-slice CT and a dual-source CT system. Images were acquired at tube voltages of 80, 100, 120, and 140 kVp and reconstructed by using both filtered back projection and iterative reconstruction algorithms. PCATMA was measured semi-automatically on CCTA images in the proximal segment of coronary arteries.ResultsThe tube voltage showed a significant effect on PCATMA measurements on both the 256-slice CT scanner (p < 0.001) and the dual-source CT system (p = 0.013), resulting in higher attenuation values with increasing tube voltage. Similarly, the use of iterative reconstructions was associated with a significant increase of PCATMA (256-slice CT: p < 0.001 and dual-source CT: p = 0.014). Averaged conversion factors to correct PCATMA measurements for tube voltage other than 120 kVp were 1.267, 1.080 and 0.947 for 80, 100, and 140 kVp, respectively.ConclusionPCATMA values are significantly affected by acquisition and reconstruction parameters. The same tube voltage and reconstruction type are recommended when PCAT attenuation is used in multicenter and longitudinal studies.Key Points• The tube voltage used for CCTA acquisition affects pericoronary adipose tissue attenuation, resulting in higher attenuation values of fat with increasing tube voltage.• Conversion factors for pericoronary adipose tissue attenuation values could be used to adjust for differences in attenuation between scans performed at different tube voltages.• In longitudinal CCTA studies employing pericoronary adipose tissue attenuation as imaging endpoint, it is recommended to maintain tube voltage and image reconstruction type constant across serial scans.

Abstract 13686: HEART Score Predicts Coronary Artery Disease on Coronary Computed Tomography Angiography in the Emergency Department Only in Patients With Three or Greater Risk Factors

Introduction: HEART (History, Electrocardiogram, Age, Risk factors, Troponin) Score (HS) predicts MACE in patients presenting to the ED with chest pain. It was validated clinically but not radiologically. Coronary computed tomography angiography (CCTA) in the ED allows for rapid triaging of patients and carries prognostic value. Objective: study relationship between HS and the presence and severity of CAD on CCTA. Methods: In this retrospective cohort, we included patients undergoing CCTA in the ED for acute chest pain between January 2014 to July 2016. HS was calculated and classified as low-risk (score &lt;=3) or high-risk (score &gt;3). A certified specialist reviewed all CCTA studies and determined the presence and severity of CAD. Anatomic CAD was defined by coronary artery calcium score (CACS) &gt;0 or the presence of any stenosis. Obstructive CAD was defined by CACS&gt;100 or coronary stenosis &gt;=50%. Multivariate regression analysis was performed to determine predictors of anatomic and obstructive CAD. We performed interaction analysis between HS and the presence of &gt;=3 traditional CAD risk factors. Results: Of the 927 CCTA performed, 315 (34%) had anatomic CAD, 128 (14%) had obstructive CAD. Mean age was 51 years, 49% were males, mean HS was 2.6, and 71% of the cohort had a low-risk HS. High HS was associated with higher proportions of CAD only in patients who had &gt;=3 traditional CAD risk factors [Fig 1]. Regression and interaction analyses showed that HS was an independent predictor of anatomic and obstructive CAD only in patient with &gt;=3 traditional CAD risk factors [Fig 2]. Conclusion: HS is a predictor of radiographic CAD on CCTA when performed in patients with &gt;=3 traditional risk factors.

Association Between Changes in Perivascular Adipose Tissue Density and Plaque Progression

BackgroundThe association between the change in vessel inflammation, as quantified by perivascular adipose tissue (PVAT) density, and the progression of coronary atherosclerosis remains to be determined. ObjectivesThe purpose of this study was to explore the association between the change in PVAT density and the progression of total and compositional plaque volume (PV). MethodsPatients were selected from a prospective multinational registry. Patients who underwent serial coronary computed tomography angiography studies with ≥2-year intervals and were scanned with the same tube voltage at baseline and follow-up were included. Total and compositional PV and PVAT density at baseline and follow-up were quantitatively analyzed for every lesion. Multivariate linear regression models using cluster analyses were constructed. ResultsA total of 1,476 lesions were identified from 474 enrolled patients (mean age 61.2 ± 9.3 years; 65.0% men). The mean PVAT density was −74.1 ± 11.5 HU, and total PV was 48.1 ± 83.5 mm3 (19.2 ± 44.8 mm3 of calcified PV and 28.9 ± 51.0 mm3 of noncalcified PV). On multivariate analysis (adjusted for clinical risk factors, medication use, change in lipid levels, total PV at baseline, luminal HU attenuation, location of lesions, and tube voltage), the increase in PVAT density was positively associated with the progression of total PV (estimate = 0.275 [95% CI: 0.004-0.545]; P = 0.047), driven by the association with fibrous PV (estimate = 0.245 [95% CI: 0.070-0.420]; P = 0.006). Calcified PV progression was not associated with the increase in PVAT density (P > 0.050). ConclusionsIncrease in vessel inflammation represented by PVAT density is independently associated with the progression of the lipid component of coronary atherosclerotic plaques. (Progression of AtheRosclerotic PlAque DetermIned by Computed TomoGraphic Angiography Imaging [PARADIGM]; NCT02803411)

Coronary artery calcium score to predict coronary CT angiography interpretability. An old problem revisited

Abstract Introduction Clinical guidelines recommend against the use of coronary computed tomography angiography (CCTA) in patients with heavy calcification due to interpretability concerns, but no specific approach or threshold is provided. Recently, alternative methods have been proposed as more reliable predictors of CCTA interpretability than the classic coronary artery calcium score (CACS). The purpose this study was to compare the performance of different measures of coronary calcification as predictors of CCTA interpretability. Methods We conducted a retrospective analysis of consecutive patients undergoing CACS and CCTA between 2018 and 2020. The key exclusion criteria were known coronary artery disease, CACS of zero, and presence of non-assessable coronary lesions for reasons other than calcification (movement/gating artifacts or vessel diameter &amp;lt;2mm). CCTA studies were considered non-interpretable if the main reader considered one or more coronary lesions non-assessable due to calcification. Three different measures of coronary calcification were compared using ROC curve analysis: 1) total CACS; 2) CACS-to-lesion ratio (total CACS divided by the number of calcified plaques); and 3) calcium score of the most calcified plaque. Decision-tree analysis was performed to identify the algorithm that best predicts CCTA interpretability. Results A total of 432 patients (191 women, mean age 64±11 years) were included. Overall, 31 patients (7.2%) had a non-interpretable CCTA due to calcification. Patients with non-interpretable CCTA had higher CACS (median 589 vs. 50 AU, p&amp;lt;0.001), higher CACS-to-lesion ratio (median 43 vs. 14 AU/lesion, p&amp;lt;0.001), and higher score of the most calcified plaque (median 445 vs. 43 AU, p&amp;lt;0.001). Among the 3 methods, CACS showed the highest discriminative power to predict a non-interpretable CCTA (C-statistic 0.93, 95% CI 0.89–0.95, p&amp;lt;0.001) – Figure 1. Decision-tree analysis identified a single-variable algorithm (CACS value ≤515 AU) as the best discriminator of CCTA interpretability: 396 of the 409 patients (97%) with CACS ≤515 AU had an interpretable CCTA, whereas only 5 of the 23 patients (22%) with CACS &amp;gt;515 AU had an interpretable test, yielding a total of 96% correct predictions. Conclusions The recently proposed and more complex measures of coronary calcification seem unable to outperform total CACS as a predictor of CCTA interpretability. A simple CACS cutoff-value around 500 AU remains the best discriminator for this purpose. Funding Acknowledgement Type of funding sources: None. Figure 1

Tomografía computarizada coronaria en urgencias: importancia de la experiencia del radiólogo

IntroductionIncorporating coronary computed tomography angiography (CTA) in the hospital workup for suspected acute coronary syndrome requires appropriate skills for interpreting this imaging test. Radiologists’ skills can affect the interobserver agreement in evaluating these studies. ObjectiveTo determine the interobserver agreement according to radiologists’ experience in the interpretation of coronary CTA studies done in patients who present at the emergency department with acute chest pain and low-to-intermediate probability of acute coronary syndrome. Materials and methodsWe studied the interobserver agreement in the urgent evaluation of coronary CTA studies in which CAD-RADS was used to register the findings. We created pairs of observers among a total of 8 assessors (4 attending radiologists and 4 radiology residents). We used the kappa coefficient to estimate the overall concordance and the concordance between subgroups according to their experience. ResultsThe agreement was substantial between experienced radiologists and residents (k = 0.627; 95%CI: 0.436 – 0.826) as well as between all the pairs of observers (k=0.661; 95%CI: 0.506 – 0.823) for all the CAD-RADS together. The degree of agreement within the group of experienced radiologists was greater than that within the group of residents in all the analyses. The agreement was excellent for the overall CAD-RADS (k=0.950; 95% CI: 0.896 – 1) and for CAD-RADS ≥ 4 (k=1); the agreement was lower for CAD-RADS ≥ 3 (k = 0.754; 95% CI: 0.246 – 1.255). The agreement for the residents for these categories was k= 0.623, k=0.596, and k=0.473, respectively. ConclusionThe agreement among attending radiologists regarding the assessment of urgent coronary CTA studies is excellent. The agreement is lower when residents are paired with attending radiologists. These findings should be taken into consideration when implementing coronary CTA in emergency departments and in the organization of radiological staff for interpreting and reporting this imaging test.

Appropriateness of inpatient stress testing: Implications for development of clinical decision support mechanisms and future criteria

BackgroundAn upcoming national mandate will require consultation of appropriate use criteria (AUC) through a clinical decision support mechanism (CDSM) for advanced imaging. We aimed to evaluate our current ability to ascertain test appropriateness. MethodsWe prospectively collected data on 288 consecutive stress tests and coronary computed tomography angiography studies for medical inpatients. Study appropriateness was determined independently by two physicians using the 2013 Multimodality AUC. ResultsThe median age of the study population was 66 years [interquartile range (IQR) 56, 75], 40.8% were female, and 52.8% had a history of coronary artery disease. Review of the electronic health record (EHR) alone was sufficient to deem appropriateness for 87.2% of cases. The most common reason it was insufficient was inability to determine if the patient could exercise (59.5%). After reviewing the EHR and pilot CDSM data together, appropriateness could be determined for 95.8% of the cases. The most common reason appropriateness could not be determined was that the exam indication was not addressed by an AUC criterion (83.3%). ConclusionIn preparing for the mandate, it will be important for future CDSM to obtain information on the patient’s ability to exercise and for future AUC to include additional indications that are not currently addressed.

Coronary artery calcium score to predict coronary CT angiography interpretability: an old problem revisited

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Clinical guidelines recommend against the use of coronary computed tomography angiography (CCTA) in patients with heavy calcification due to interpretability concerns, but no specific approach or threshold is provided. Recently, alternative methods have been proposed as more reliable predictors of CCTA interpretability than the classic coronary artery calcium score (CACS). The purpose this study was to compare the performance of different measures of coronary calcification as predictors of CCTA interpretability. Methods We conducted a retrospective analysis of consecutive patients undergoing CACS and CCTA between 2018 and 2020. The key exclusion criteria were known coronary artery disease, CACS of zero, and presence of non-assessable coronary lesions for reasons other than calcification (movement/gating artifacts or vessel diameter &amp;lt; 2mm). CCTA studies were considered non-interpretable if the main reader considered one or more coronary lesions non-assessable due to calcification. Three different measures of coronary calcification were compared using ROC curve analysis: 1) total CACS; 2) CACS-to-lesion ratio (total CACS divided by the number of calcified plaques); and 3) calcium score of the most calcified plaque. Decision-tree analysis was performed to identify the algorithm that best predicts CCTA interpretability. Results A total of 432 patients (191 women, mean age 64 ± 11 years) were included. Overall, 31 patients (7.2%) had a non-interpretable CCTA due to calcification. Patients with non-interpretable CCTA had higher CACS (median 589 vs. 50 AU, p &amp;lt; 0.001), higher CACS-to-lesion ratio (median 43 vs. 14 AU/lesion, p &amp;lt; 0.001), and higher score of the most calcified plaque (median 445 vs. 43 AU, p &amp;lt; 0.001). Among the 3 methods, CACS showed the highest discriminative power to predict a non-interpretable CCTA (C-statistic 0.93, 95%CI 0.89-0.95, p &amp;lt; 0.001) - Figure. Decision-tree analysis identified a single-variable algorithm (CACS value ≤ 515 AU) as the best discriminator of CCTA interpretability: 396 of the 409 patients (97%) with CACS ≤ 515 AU had an interpretable CCTA, whereas only 5 of the 23 patients (22%) with CACS &amp;gt; 515 AU had an interpretable test, yielding a total of 96% correct predictions. Conclusions The recently proposed and more complex measures of coronary calcification seem unable to outperform total CACS as a predictor of CCTA interpretability. A simple CACS cutoff-value around 500 AU remains the best discriminator for this purpose.

Correlation between Body Mass Index and Radiation Dose in Patients Undergoing Coronary Computed Tomography Angiography

ABSTRACT Background: Radiation dose is an important factor in performing a coronary Computed Tomography Angiography (CTA). Objective: To assess the correlation between Body Mass Index (BMI) and radiation dose in patients receiving a Coronary CTA. Methods: All retrospectively EKG gated coronary CTA studies using a 64 slice CT in patients above 18 years old, during a one-year time period were included in the study. The data was obtained by a query of the PACS system. Sixteen of the total 75 subjects were excluded due to lack of BMI or Dose length product (DLP) data or the CTA deviated from standard protocol. Seven of these patients were specifically excluded by using an x-ray tube voltage other than the standard 120 kVp. For the remaining 52 subjects, correlation and linear regression statistical analysis was used to analyze the relationship between BMI and DLP. Pearson correlation coefficient was calculated using Microsoft Excel. Results: There was a weak correlation between the BMI and DLP with a coefficient of determination value of 0.0217. Conclusion: When appropriate criteria exist for obtaining a coronary CTA, a high BMI should not deter ordering based only on high radiation dose concerns since correlation between BMI and DLP is weak.

Clinical significance of incidental findings on coronary CT angiography: Insights from a randomized controlled trial

BackgroundThe effect of incidental findings from coronary computed tomography angiography (CCTA) on management has not been rigorously investigated. This study uses a control group to explore this relationship. MethodsAnalysis of data from a randomized controlled trial of acute chest pain patients admitted to telemetry was performed. Patients were randomized to undergo either CCTA (n = 200) or radionuclide myocardial perfusion imaging (MPI) (n = 200). Incidental findings were determined from imaging reports. Records were reviewed to determine subsequent management and imaging during and after hospitalization. Comparisons were performed using Fischer’s exact tests. Results386 incidental findings were found among 187 CCTA studies. No extra-cardiac incidental findings were noted in the MPI arm, which served as an effective control group. There were significantly more non-coronary medical workups during admission in the CCTA group compared to the MPI group [20% (39) vs. 12% (23), P = 0.038]. CCTA patients underwent significantly more resting echocardiography during the inpatient workup compared to the MPI group [38% (75) vs. 18% (55), P = 0.042]. CCTA patients underwent significantly more non-contrast chest CT exams in the year following admission compared to MPI patients [14% (27) vs. 7% (13) P = 0.029]. ConclusionsIncidental findings on inpatient CCTAs performed for chest pain have a significant impact on treatment and imaging during and following hospital admission.

Diagnostic accuracy of early computed tomographic coronary angiography to detect coronary artery disease after out-of-hospital circulatory arrest

AimTo test the diagnostic accuracy of ECG-gated coronary computed tomography angiography (CCTA) to detect coronary artery disease (CAD) among survivors of out-of-hospital circulatory arrest (OHCA). MethodsWe prospectively studied head-to-pelvis computed tomography (CT) scanning (<6 h from hospital arrival) in OHCA survivors. This sub-study tested the primary outcome of CCTA diagnostic accuracy to identify obstructive CAD (≥50% stenosis) compared to clinically-ordered invasive coronary angiography. Patients were not optimized with beta receptor blockade or nitroglycerin. Secondary analyses included CCTA accuracy for CAD in major coronary arteries, obstructive disease at ≥70% stenosis threshold, and where non-evaluable CCTA segments were considered either obstructive or non-obstructive. ResultsOf the 104 enrolled OHCA survivors, 28 (27%) received both CT and invasive angiography in this sub study. All CCTA studies were evaluable although 49/346 (14%) individual coronary segments were unevaluable, primarily due to being too small to evaluate (65%). Patient-level diagnostic accuracy for the ≥50% stenosis threshold was high at 0.93 (95% CI 0.77–0.98) with a specificity of 1.0 (95% CI 0.8–1.0), sensitivity of 0.85 (95%CI 0.58–0.96), negative predictive value of 0.88 (95% CI 0.66–0.97) and positive predictive value of 1.0 (0.74–1.0). When non-evaluable segments were considered obstructive, the sensitivity rose to 0.92 (95% CI 0.67–0.99) with lower specificity of 0.27 (95% CI 0.11–0.52). ConclusionEarly CCTA of OHCA survivors has high diagnostic accuracy to detect obstructive coronary artery disease. However, the number of non-diagnostic coronary segments is high suggesting further CCTA refinement is needed, such as the pre-CCTA use of nitroglycerin. Clinical Trial RegistrationNCT03111043 https://clinicaltrials.gov/ct2/show/record/NCT03111043

The effects of sublingual nitroglycerin administration in coronary computed tomography angiography

PurposeThe purpose of our study was to compare coronary luminal diameters in patients undergoing coronary computed tomography angiography (CCTA) performed with different sublingual nitroglycerin (NTG) spray regimens. Materials and methodsWe retrospectively reviewed CCTA studies performed in two historical groups (Group 1, single dose nitroglycerin 2 min prior to CCTA, and Group 2, single dose 10 min prior), and a current protocol group (Group 3, single dose at 2 and 10 min prior). Thirty patients were evaluated per group. Two blinded readers measured coronary luminal diameters with comparison of diameter measurements. A third blinded reader assessed image quality of coronary artery segments. ResultsSignificant group-level differences in median luminal diameters were identified. Higher median diameters (95% CI) across all segments of 0.40 mm (0.20, 0.60) for Group 2 versus 1 and 0.50 mm (0.30, 0.70) for Group 3 versus 1 were recorded (both P < 0.001). No significant differences in median luminal diameters were found between Groups 2 and 3. No significant differences in image quality were found among the groups apart from higher image quality for the distal LAD for both Groups 2 and 3 compared to Group 1. ConclusionSublingual nitroglycerin spray administered as a single dose at 10 minute dilates coronary arteries more than when only administered at 2 min prior to CCTA. Combined two doses at 10 and 2 min prior to CCTA do not yield further dilatation of coronary arteries.

Reference values for mid-diastolic right ventricular volume in population referred for cardiac computed tomography: An additional diagnostic value to cardiac computed tomography

BackgroundWhile an assessment of the right ventricular (RV) size remains challenging, the entire RV is can be imaged on coronary computed tomography angiography (CCTA) studies. With prospective ECG-triggering, the RV end diastolic volume (RVEDV) cannot be measured; however, the RV mid-diastolic volume (RVMDV) can still be measured accurately from routine CCTA data sets. The objective of this study is to establish normal reference values for RVMDV. MethodsRight ventricular mid-diastolic volumes were measured in 4855 consecutive patients undergoing prospectively ECG-triggered coronary CTA. All patients with known cardiac or pulmonary disease (coronary artery disease, myocardial infarction, revascularization, heart failure, pulmonary hypertension, congenital heart disease, valvular heart disease, atrial fibrillation, implantable cardiac defibrillator implantation, cardiac transplant, or cardiac surgery) or smoking history (3313 patients) were excluded. Results1542 patients were analyzed (mean age 56.4 ± 11.1 years, mean BSA 1.96 ± 0.26 and 47% male). The mean RVMDV for men and women was 168.6 ± 37.6 mL and 117.6 ± 26.4 mL, respectively. Mean BSA-indexed RVMDV was 80.0 ± 15.3 mL/m2 and 64.1 ± 12.2 mL/m2 for men and women, respectively. The presence of hypertension and diabetes did not have an impact on these values. RVMDV and BSA-indexed RVMDV were lower in women and in older individuals. ConclusionNormal reference ranges for RVMDV were established using prospectively ECG-triggered coronary CTA studies. This data can be used to identify patients with abnormal RV volumes and potentially RV dysfunction, adding incremental diagnostic value to routine CCTA studies.

Incidental Non-cardiac Findings in Coronary Computed Tomography Angiography: Is it Worth Reporting?

Objectives:The objectives of this study were to estimate the prevalence and significance of incidental non-cardiac findings (INCFs) in coronary computed tomography angiography (CCTA) using a dual-source multidetector computed tomography.Materials and Methods:Retrospective review of all CCTA studies performed over a time period for various indications was included in the study. After exclusions, CCTA of 1713 patients was evaluated by two experienced cardiac radiologists for non-cardiac abnormalities in the full field-of-view limited contrast chest series. The scans were acquired from the level of the carina to just below the diaphragm. INCFs were classified into three categories: Significant, indeterminate, and insignificant findings based on their clinical impact and availability of prior imaging and clinical details.Results:The study cohort consisted of 1123 males (mean age of 58 years) and 590 females (mean age of 64 years). INCFs were seen in 600 patients of 1713 patients. A total of 812 INCFs (47.5%) were found in 1713 patients. Of those, 568 (70%) were considered insignificant, 205 (25.2%) indeterminate, and 39 significant findings (4.9%). The prevalence of significant findings was 2.3%. Among the 39 significant findings, after correlating with clinical details and other imaging, nine were really significant findings (0.5%) and out of this, four turned out to be cancers (0.2%).Conclusion:Large number of INCFs can be found in CCTA with majority of them being insignificant or of minimal clinical impact. Although the proportion of significant findings is small and may not be cost beneficial, it is prudent to evaluate all the available data and to make appropriate classification of INCFs which can help in further management.

Diagnostic accuracy of 3D deep-learning-based fully automated estimation of patient-level minimum fractional flow reserve from coronary computed tomography angiography.

Although deep-learning algorithms have been used to compute fractional flow reserve (FFR) from coronary computed tomography angiography (CCTA), no study has achieved 'fully automated' (i.e. free from human input) FFR calculation using deep-learning algorithms. The purpose of the study was to evaluate the accuracy of a fully automated 3D deep-learning model for estimating minimum FFR from CCTA data, with invasive FFR as the reference standard. This retrospective study of 1052 patients included 131 patients whose CCTA studies showed 30-90% stenosis and underwent invasive FFR (abnormal FFR observed in 72/131, 55%), and 921 patients who underwent clinically indicated CCTA without invasive FFR. We designed a fully automated 3D deep-learning model that inputs CCTA data and outputs minimum FFR without requiring human input. The model comprised a series of deep-learning algorithms: a conditional generative adversarial network, a 3D convolutional ladder network, and two independent neural networks with integrated virtual adversarial training. We used Monte Carlo cross-validation to evaluate the accuracy of the model for estimating FFR, with invasive FFR as the reference standard. The deep-learning FFR achieved area under the receiver-operating characteristic curve of 0.78 for detection of abnormal FFR; and was significantly higher than for visually determined CCTA >50% stenosis (area under the curve = 0.56). The deep-learning FFR model achieved 76% accuracy for detecting abnormal FFR, with sensitivity of 85% (79-89%) and specificity of 63% (54-70%). The 3D deep-learning model, which performs fully automatic estimation of minimum FFR from cardiac CT data, achieved 76% accuracy in detecting abnormal FFR.

Relationship between changes in pericoronary adipose tissue attenuation and coronary plaque burden quantified from coronary computed tomography angiography

Increased attenuation of pericoronary adipose tissue (PCAT) around the proximal right coronary artery (RCA) from coronary computed tomography angiography (CTA) has been shown to be associated with coronary inflammation and improved prediction of cardiac death over plaque features. Our aim was to investigate whether PCAT CT attenuation is related to progression of coronary plaque burden. We analysed CTA studies of 111 stable patients (age 59.2 ± 9.8 years, 77% male) who underwent sequential CTA (3.4 ± 1.6 years between scans) with identical acquisition protocols. Total plaque (TP), calcified plaque (CP), non-calcified plaque (NCP), and low-density non-calcified plaque (LD-NCP) volumes and corresponding burden (plaque volume × 100%/vessel volume) were quantified using semi-automated software. PCAT CT attenuation (HU) was measured around the proximal RCA, the most standardized method for PCAT analysis. Patients with an increase in NCP burden (n = 51) showed an increase in PCAT attenuation, whereas patients with a decrease in NCP burden (n = 60) showed a decrease {4.4 [95% confidence interval (CI) 2.6-6.2] vs. -2.78 (95% CI -4.6 to -1.0) HU, P < 0.0001}. Changes in PCAT attenuation correlated with changes in the burden of NCP (r = 0.55, P < 0.001) and LD-NCP (r = 0.24, P = 0.01); but not CP burden (P = 0.3). Increased baseline PCAT attenuation ≥-75 HU was independently associated with increase in NCP (odds ratio 3.07, 95% CI 1.4-7.0; P < 0.008) and TP burden on follow-up CTA. PCAT attenuation measured from routine CTA is related to the progression of NCP and TP burden. This imaging biomarker may help to identify patients at increased risk of high-risk plaque progression and allow monitoring of beneficial changes from medical therapy.