Diagnostic accuracy of non-invasive 64-slice CT coronary angiography in patients with stable angina pectoris

A meta-analysis comparing the diagnostic performance of computed tomography-derived fractional flow reserve and coronary computed tomography angiography at different levels of coronary artery calcium score

OBJECTIVES

The impact of coronary calcification on the diagnostic accuracy of computed tomography-derived fractional flow reserve (CT-FFR) and coronary computed tomography angiography (CCTA) remains a crucial consideration. This meta-analysis aims to compare the diagnostic performance of CT-FFR and CCTA at different levels of coronary artery calcium score (CACS).

METHODS AND RESULTS

We searched PubMed, Embase, and the Cochrane Library for relevant articles on CCTA, CT-FFR, and invasive fractional flow reserve (FFR). Ten studies were included to evaluate the diagnostic performance of CT-FFR and CCTA at the per-patient and per-vessel levels in four CACS groups. Invasive FFR was used as the reference standard. Except for the CACS ≥ 400 group, the AUC of CT-FFR was higher than those of CCTA in other subgroups of CACS (in CACS < 100 (per-patient, 0.9 (95% CI 0.87-0.92) vs. 0.32 (95% CI 0.28-0.36); per-vessel, 0.92 (95% CI 0.89-0.94) vs. 0.66 (95% CI 0.62-0.7); both p < 0.001), CACS ≥ 100 (per-patient, 0.86 (95% CI 0.82-0.88) vs. 0.44 (95% CI 0.4-0.48); per-vessel, 0.88 (95% CI 0.85-0.9) vs. 0.51 (95% CI 0.46-0.55); both p < 0.001), and CACS < 400 (per-patient, 0.9 (95% CI 0.87-0.93) vs. 0.74 (95% CI 0.7-0.78), p < 0.001; per-vessel, 0.8 (95% CI 0.76-0.83) vs. 0.74 (95% CI 0.7-0.78); p = 0.02)).

CONCLUSIONS

CT-FFR demonstrates superior diagnostic performance in low CACS groups (CACS < 400) than CCTA in detecting hemodynamic stenoses in patients with coronary artery disease (CAD).

CLINICAL RELEVANCE STATEMENT

Computed tomography-derived fractional flow reserve might be utilized to determine the necessity of invasive coronary angiography in coronary artery disease patients with coronary artery calcium score < 400.

KEY POINTS

• There is a lack of meta-analysis comparing the diagnostic performance of computed tomography-derived fractional flow reserve and coronary computed tomography angiography at different levels of calcification. • Computed tomography-derived fractional flow reserve only has a better diagnostic performance than coronary computed tomography angiography with low amounts of coronary calcium. • For the low coronary artery calcium score group, computed tomography-derived fractional flow reserve might be a good non-invasive method to detect hemodynamic stenoses in coronary artery disease patients.

Positive Predictive Value of Computerized Tomography Coronary Angiography versus Computerized Tomography Fractional Flow Reserve in a Real-world Population

Background

Computed Tomography coronary angiography and fractional flow reserve (CTCA and CT-FFR) are noninvasive diagnostic tools for the detection of flow-limiting coronary artery stenoses. Although their negative predictive values are well established, there is a concern that the high sensitivity of these tests may lead to overestimation of coronary artery disease (CAD) and unnecessary invasive coronary angiography (ICA). We compared the positive predictive value (PPV) of CT-FFR with computerized tomography coronary angiography (CTCA) against the gold standard of ICA in different real-world patient groups.

Methods

A retrospective analysis of 477 patients referred for CTCA or CT-FFR for investigation of possible coronary ischemia. Patients were excluded if the image quality was poor or inconclusive. Patient-based PPV was calculated to detect or rule out significant CAD, defined as more than 70% stenosis on ICA. A sub-analysis of PPV by indication for the scan was also performed. Patients who underwent invasive nonhyperemic pressure wire measurements had their instant wave-free ratio or resting full-cycle ratio compared with their CT-FFR values.

Results

In a patient-based analysis, the overall PPV was 59.3% for CTCA and 76.2% for CT-FFR. This increased to 81.0% and 86.7%, respectively, for patients with stable angina symptoms. In patients with atypical angina symptoms, CT-FFR considerably outperformed CTCA with a PPV of 61.3% vs. 37.5%. There was not a linear relationship between invasive pressure wire measurement and CT-FFR value (r = 0.23, P = 0.265).

Conclusion

The PPV of CTCA and CT-FFR is lower in the real world than in previously published trials, partly due to the heterogeneity of indication for the scan. However, in patients with typical angina symptoms, both are reliable diagnostic tools to determine the presence of clinically significant coronary stenoses. CT-FFR significantly outperforms CTCA in patients with more atypical symptoms and the targeted use of CT-FFR in this group may help to avoid unnecessary invasive procedures.

Computed tomography of coronary artery atherosclerosis: A review

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

Clinical pre-test probability for obstructive coronary artery disease: insights from the European DISCHARGE pilot study

Objectives

To test the accuracy of clinical pre-test probability (PTP) for prediction of obstructive coronary artery disease (CAD) in a pan-European setting.

Methods

Patients with suspected CAD and stable chest pain who were clinically referred for invasive coronary angiography (ICA) or computed tomography (CT) were included by clinical sites participating in the pilot study of the European multi-centre DISCHARGE trial. PTP of CAD was determined using the Diamond-Forrester (D+F) prediction model initially introduced in 1979 and the updated D+F model from 2011. Obstructive coronary artery disease (CAD) was defined by one at least 50% diameter coronary stenosis by both CT and ICA.

Results

In total, 1440 patients (654 female, 786 male) were included at 25 clinical sites from May 2014 until July 2017. Of these patients, 725 underwent CT, while 715 underwent ICA. Both prediction models overestimated the prevalence of obstructive CAD (31.7%, 456 of 1440 patients, PTP: initial D+F 58.9% (28.1–90.6%), updated D+F 47.3% (34.2–59.9%), both p < 0.001), but overestimation of disease prevalence was higher for the initial D+F (p < 0.001). The discriminative ability was higher for the updated D+F 2011 (AUC of 0.73 95% confidence interval [CI] 0.70–0.76 versus AUC of 0.70 CI 0.67–0.73 for the initial D+F; p < 0.001; odds ratio (or) 1.55 CI 1.29–1.86, net reclassification index 0.11 CI 0.05–0.16, p < 0.001).

Conclusions

Clinical PTP calculation using the initial and updated D+F prediction models relevantly overestimates the actual prevalence of obstructive CAD in patients with stable chest pain clinically referred for ICA and CT suggesting that further refinements to improve clinical decision-making are needed.

Trial registration

https://www.clinicaltrials.gov/ct2/show/NCT02400229

Key Points

• Clinical pre-test probability calculation using the initial and updated D+F model overestimates the prevalence of obstructive CAD identified by ICA and CT.

• Overestimation of disease prevalence is higher for the initial D+F compared with the updated D+F.

• Diagnostic accuracy of PTP assessment varies strongly between different clinical sites throughout Europe.

Electronic supplementary material

The online version of this article (10.1007/s00330-020-07175-z) contains supplementary material, which is available to authorized users.

Decision tree-based diagnosis of coronary artery disease: CART model

BACKGROUND AND OBJECTIVE

As the most common cardiovascular defect, coronary artery disease (CAD), also called ischemic heart disease, is one of the substantial causes of death globally. Several diagnosis approaches such as baseline electrocardiography, echocardiography, magnetic resonance imaging, and coronary angiography are suggested for screening the suspected patients that may suffer from CAD. However, applying such methods may have health side effects and/or expensive costs.

METHODS

As an alternative to the available diagnosis tools/methods, this research involves a decision tree learning algorithm called classification and regression tree (CART) for a simple and reliable diagnosis of CAD. Several CART models are developed based on the recently CAD dataset published in the literature.

RESULTS

Utilizing all the features of the dataset (55 independent parameters), it was found that only 40 independent parameters influence the CAD diagnosis and consequently development of the predictive model. Based on the feature importance obtained from the first CART model, three new CART models are then developed using 18, 10, and 5 selected features. Except for the five-feature CART model, the outcomes of developed CART models demonstrate the maximum achievable accuracy, sensitivity, and specificity for CAD diagnosis (100%), while comparing the predictions with the reported targets. The error analysis reveals that the literature models including sequential minimal optimization (SMO), bagging SMO, Naïve Bayes (NB), artificial neural network (ANN), C4.5, J48, Bagging, and ANN in conjunction with the genetic algorithm (GA) do not outperform the CART methodology in classifying patients as normal or CAD.

CONCLUSIONS

Hence, the robustness of the tree-based algorithm in accurate and fast predictions is confirmed, implying the proposed classification technique can be successfully utilized to develop a coherent decision-making system for the CAD diagnosis.

Emerging techniques in atherosclerosis imaging

Atherosclerosis is a chronic immunomodulated disease that affects multiple vascular beds and results in a significant worldwide disease burden. Conventional imaging modalities focus on the morphological features of atherosclerotic disease such as the degree of stenosis caused by a lesion. Modern CT, MR and positron emission tomography scanners have seen significant improvements in the rapidity of image acquisition and spatial resolution. This has increased the scope for the clinical application of these modalities. Multimodality imaging can improve cardiovascular risk prediction by informing on the constituency and metabolic processes within the vessel wall. Specific disease processes can be targeted using novel biological tracers and "smart" contrast agents. These approaches have the potential to inform clinicians of the metabolic state of atherosclerotic plaque. This review will provide an overview of current imaging techniques for the imaging of atherosclerosis and how various modalities can provide information that enhances the depiction of basic morphology.

Myocardial Perfusion by Coronary Computed Tomography in the Evaluation of Myocardial Ischemia: Simultaneous Stress Protocol with SPECT

BACKGROUND

Functional assessment to rule out myocardial ischemia using coronary computed tomography angiography (CCTA) is extremely important and data on the Brazilian population are still limited.

OBJECTIVE

To assess the diagnostic performance of myocardial perfusion by CCTA in the detection of severe obstructive coronary artery disease (CAD) compared with single-photon emission computerized tomography (SPECT). To analyze the importance of anatomical knowledge to understand the presence of myocardial perfusion defects on SPECT imaging that is not identified on computed tomography (CT) scan.

METHOD

A total of 35 patients were evaluated by a simultaneous pharmacologic stress protocol. Fisher's exact test was used to compare proportions. The patients were grouped according to the presence or absence of significant CAD. The area under the ROC curve was used to identify the diagnostic performance of CCTA and SPECT in perfusion assessment. P < 0.05 values were considered statistically significant.

RESULTS

For detection of obstructive CAD, CT myocardial perfusion analysis yielded an area under the ROC curve of 0.84 [a 95% confidence interval (CI95%): 0.67-0.94, p < 0.001]. SPECT myocardial perfusion imaging, on the other hand, showed an AUC of 0.58 (95% CI 0.40 - 0.74, p < 0.001). In this study, false-positive results with SPECT are described.

CONCLUSION

Myocardial perfusion analysis by CTA displays satisfactory results compared to SPECT in the detection of obstructive CAD. CCTA can rule out false-positive results of SPECT.

Low-Dose Coronary CT Angiography in Patients with Atrial Fibrillation: Comparison of Image Quality and Radiation Exposure with Two Different Approaches

RATIONALE AND OBJECTIVES

To evaluate image quality, coronary interpretability and radiation exposure of coronary CT angiography (CCTA) performed in patients with atrial fibrillation (AF) with the latest scanner generation, comparing two different technical approaches. A new scanner that combines a 0.23 mm spatial resolution, a new generation of iterative reconstruction, fast gantry rotation time and the intracycle motion-correction algorithm to improve the temporal resolution was recently introduced in the clinical field.

MATERIALS AND METHODS

We enrolled 105 consecutive patients with chronic AF who performed CCTA with a whole-heart coverage high-definition CT scanner (16-cm z-axis coverage with 256 detector rows, 0.28 s gantry rotation time). Five of them were excluded for impaired renal function. Patients were randomized between a double acquisition protocol (50 patients, group 1) or a single acquisition protocol (50 patients, group 2). The image quality, coronary segment interpretability and effective dose (ED) of CCTA were assessed.

RESULTS

The mean HR during the scan was 85.6±21 bpm in group 1 vs. 83.7±23 bpm in Group 2, respectively (p < ns). In group 2, overall image quality was high and comparable with that of group 1 (Likert scale =3.2 ± 1.4 vs. 3.3 ± 1.2, p = ns, in group 1 and 2, respectively). Coronary interpretability was high and similar between the two groups (97.5% and 97.1% in group 1 and 2, p = ns, respectively). Mean ED was significantly higher in group 1 than in group 2 (5.3 ± 1.8 mSv vs. 2.7 ± 0.7 mSv, p < 0.001).

CONCLUSION

The novel whole-heart coverage CT scanner allows to perform CCTA with a single-acquisition protocol with high image quality and low radiation exposure in AF patients.

Effect of bolus tracking region-of-interest position within the descending aorta on luminal enhancement of coronary arteries in coronary computed tomography angiography

To compare coronary artery luminal enhancement in coronary computed tomography angiography (CCTA) between ventral and dorsal region-of-interest (ROI) bolus tracking in the descending aorta.The records of 165 consecutive patients who underwent CCTA with non-helical acquisition from July 2017 to March 2018 were retrospectively examined. We performed 320-row CCTA with bolus tracking [scan triggered at 260 HU in the descending aorta] and 133 patients were finally included. ROI was set in the ventral and dorsal halves of the descending aorta in 68 and 65 patients, respectively.Contrast arrival time was significantly shorter in the dorsal group (ventral: 21.8 ± 0.372 s; dorsal: 20.7 ± 0.369; P = .0295). The mean density of the proximal and distal RCA was significantly higher in the ventral group (proximal: ventral, 428.1 ± 6.95 HU; dorsal, 405.5 ± 7.72 HU, P = .0318; distal: ventral, 418.0 ± 9.29 HU; dorsal, 393.2 ± 9.46 HU, P = .0133).Dorsal bolus tracking ROI in the descending thoracic aorta significantly reduced preparation time and RCA CT values.

Reduced artifacts and improved diagnostic value of 640-slice computed tomography in patients with cardiac pacemakers

Objective

The aim of this study was to compare the feasibility of 640-slice with 64-slice computed tomography (CT) coronary angiography for diagnosing coronary lesions in patients with pacemakers.

Methods

Forty-five and 50 patients with pacemakers and with suspected or known coronary artery disease underwent 64-slice (64 group) and 640-slice (640 group) CT scans, respectively. All segments of the vessels were evaluated according to the 15-segment model recommended by the American Heart Association.

Results

The incidence of moderate or severe artifacts was significantly lower (7.27% vs. 32.17%) and the diagnosable rate for coronary lesions was higher (98.91% vs. 94.19%) in the 640 compared with the 64 group. In the 64 group, the incidence of artifacts in patients with a heart rate >65 bpm (20.98%) was higher than in those with a heart rate <65 bpm (15.67%), although the difference was not significant, while the incidence of artifacts was significantly higher in patients with heart arrhythmia (21.40%) compared with in those with normal heart rhythm (15.09%).

Conclusions

Among patients with pacemakers and a higher heart rate or heart arrhythmia, 640-slice CT may be more effective than 64-slice CT for diagnosing coronary lesions, by reducing moderate and severe artifacts.

Computed tomography coronary angiography in patients without known coronary artery disease can demonstrate possible non-cardiovascular causes of non-acute retrosternal chest pain

OBJECTIVES

To assess the computed tomography coronary angiography (CTCA) accuracy for demonstrating possible non-cardiovascular causes of non-acute retrosternal chest pain in patients without known coronary artery disease (CAD) and to correlate CTCA results with the patient management and relief from pain.

METHODS

This prospective observational study was approved by the ethical committee. Consecutive patients suffering non-acute chest pain who underwent CTCA and with not known CAD were enrolled and classified as having coronary diseases (CD) or extracardiac diseases (ECD). Association between age, sex, body mass index (BMI), cardiovascular risk factors, and type of chest pain with CD or ECD was estimated. Correlation between BMI classes and each risk factor was also calculated.

RESULTS

A total of 106 patients (60 males; age 62 ± 14 years [mean ± standard deviation]; mean BMI 27) were enrolled. Hypertension was found in 71/106 (67%); smoking was significantly more frequent among males (p = 0.003) and hypercholesterolemia among females (p = 0.017); hypertension and hypercholesterolemia significantly correlated with age, and hypertension also with BMI. Pain was atypical in 70/106 (66%) patients. The kind of pain did not correlate with disease or gender. CTCA showed possible causes of chest pain in 69/106 (65%) patients; 32/69 (47%) having only CD, 23/69 (33%) only ECD, and 14/69 (20%) both CD and ECD. Prevalence was: hiatal hernia 35/106 (33%); significant CAD 24/106 (23%); myocardial bridging 22/106 (21%). At follow-up of 94/106 (89%) patients, 71/94 (76%) were pain-free, 14/17 (82%) significant CAD had been treated, and only one patient with non-significant CAD was treated after CTCA.

CONCLUSION

CTCA suggested possible causes of non-acute pain in 65% of patients.

MAIN MESSAGES

• CTCA can either rule in or rule out possible causes of chest pain alternative to CAD. • Clinically relevant findings were detected in 65% of patients with non-acute chest pain. • Non-cardiovascular diseases potentially explained symptoms in 35% of patients.

Accuracy and clinical outcomes of coronary CT angiography for patients with suspected coronary artery disease: a single-centre study in Singapore

INTRODUCTION

This study aimed to assess the accuracy and outcomes of coronary computed tomography angiography (CCTA) performed in a regional hospital in Singapore.

METHODS

The Changi General Hospital CCTA database was retrospectively analysed over a 24-month period. Electronic hospital records, catheter coronary angiography (CCA) and CCTA electronic databases were used to gather data on major adverse cardiovascular events (MACE) and CCA results. CCTA findings were deemed positive if coronary artery stenosis ≥ 50% was reported or if the stenosis was classified as moderate or severe. CCA findings were considered positive if coronary artery stenosis ≥ 50% was reported.

RESULTS

The database query returned 679 patients who had undergone CCTA for the evaluation of suspected coronary artery disease. Of the 101 patients in the per-patient accuracy analysis group, there were six true negatives, one false negative, 81 true positives and 13 false positives, resulting in a negative predictive value of 85.7% and positive predictive value of 86.2%. The mean age of the study sample was 53 ± 13 years and 255 (37.6%) patients were female. Mean duration of patient follow-up was 360 days. Of the 513 negative CCTA patients, none developed MACE during the follow-up period, and of the 164 positive CCTA patients, 19 (11.6%) developed MACE (p < 0.001).

CONCLUSION

Analysis of CCTA studies suggested accuracy and outcomes that were consistent with published clinical data. There was a one-year MACE-free warranty period following negative CCTA findings.

Impact of Calcium Score on Agreement Between Multidetector Computed Tomography and Invasive Coronary Angiography

INTRODUCTION AND OBJECTIVES

Multidetector computed tomography (MDCT) has been demonstrated as a feasible alternative to invasive coronary angiography (ICA). However, contradictory results have been reported regarding the effect of coronary artery calcium score (CS) on the diagnostic accuracy of MDCT. Our aim was to assess the agreement of MDCT and ICA and to evaluate the influence of CS on this agreement.

METHODS

We enrolled 266 consecutive patients who underwent evaluation with 64-slice MDCT and ICA. Standard CS software tools were used to calculate the Agatston score. Stenosis was qualitatively classified as mild, moderate, or severe by 1 blinded observer and the results were compared with those of ICA, which was used as the gold standard.

RESULTS

The mean age of the patients was 65.4 ± 11.2 years, and 188 patients (70.3%) were men. A total of 484 segments with coronary stenosis ≥ mild were qualitatively evaluated and quantified with MDCT. Noninvasive measurements were concordant with ICA in 402 stenoses (83.05%; Kappa, 0.684), with no significant differences between vessels and with no statistically significant influence of CS on this agreement (OR, 0.93; 95%CI, 0.76-1.09; P = .21). Multidetector computed tomography had high sensitivity, specificity, positive predictive value, and negative predictive value on a per-segment, per-vessel, and per-patient basis.

CONCLUSIONS

Non-ICA using MDCT showed good agreement with ICA in the qualitative quantification coronary stenosis and CS had no significant impact on this agreement.

The evolving view of coronary artery calcium and cardiovascular disease risk

Calcification of the coronary artery is a complex pathophysiologic process that is intimately associated with atherosclerosis. Extensive investigation has demonstrated the value of identifying and quantifying coronary artery calcium (CAC) in atherosclerotic cardiovascular disease (CVD) prognostication. However, over the last several years, an increasing body of evidence has suggested that CAC has underappreciated aspects that modulate, and at times attenuate, future CVD risk. The most commonly used measure of CAC, the Agatston unit, effectively models both higher density and higher area of CAC as risk factors for future CVD events. Recent findings from the Multi-Ethnic Study of Atherosclerosis (MESA) have challenged this assumption, demonstrating that higher density of CAC is protective for coronary heart disease and CVD events. Statins may be associated with an increase in CAC, an unexpected finding given their clear benefits in the prevention and treatment of CVD. Studies utilizing intracoronary ultrasound and coronary computed tomography angiography have demonstrated that calcified atherosclerotic plaque-as compared with noncalcified or sparsely calcified plaque-is associated with fewer CVD events. These studies lend support to the often-asserted (but as yet unvalidated) view that calcification may play a role in plaque stabilization. Furthermore, vascular calcification, though a surrogate for atherosclerotic plaque burden, may also possess identifiable aspects that can refine CVD risk assessment.

Computed tomography coronary angiography is the way forward for evaluation of children with Kawasaki disease

Kawasaki disease (KD) is an acute idiopathic vasculitis affecting infants and children. Coronary artery abnormalities and myocarditis are the major cardiovascular complications of KD. Coronary artery abnormalities develop in 15–25% of untreated KD. Two-dimensional transthoracic echocardiography has hitherto been considered the modality of choice for evaluation of children with KD. There are, however, several limitations inherent to echocardiography - including limited evaluation of distal vessels, left circumflex artery and poor acoustic window in growing children. Catheter angiography is the gold standard for evaluation of coronary artery abnormalities in older children and adults; however it also has inherent limitations - including complications related to its invasive nature, higher radiation exposure, and inability to evaluate intramural abnormalities. Thus serial invasive coronary angiography studies are not feasible in children. There have been major advances in computed tomography (CT) coronary imaging so that it is now possible to delineate the coronary artery anatomy with higher temporal resolution and motion-free images at all heart rates with acceptable radiation exposure. There is, however, a paucity of literature with regard to the use of this technique in children with KD. In this review, we discuss the application of computed tomography coronary angiography (CTCA) in children with KD with special reference to strategies aimed at reducing the effective radiation dose.

Computed Tomography Coronary Angiography for Evaluation of Children With Kawasaki Disease

OBJECTIVE

We sought to assess the feasibility of computed tomography coronary angiography (CTCA) on a 128-slice, dual source scanner in children with acute and convalescent phase Kawasaki disease (KD).

MATERIALS AND METHODS

A prospective study of 49 children with KD (12 at presentation and 37 in the convalescent phase) was conducted between November 2013 and April 2015. CTCA was performed with either prospective (n = 37) or retrospective (n = 12) electrocardiographic gating. A radiologist blinded to clinical profile and echocardiogram evaluated each scan.

RESULTS

Median age (36 boys and 13 girls) was 7 years. Median dose-length product value and median effective CT radiation dose was 32mGycm (interquartile range [IQR]: 21-74) and 0.54 miliSieverts (mSv) (IQR: 0.77-3.2) for all scans, and 27mGycm (IQR: 18.5-33.75) and 0.48mSv (IQR: 0.18-1.17) for prospectively triggered scans (n = 37). Fourteen subjects (30 coronary segments) showed abnormalities by CTCA including aneurysms (n = 27) and stenoses (n = 3). In the acute phase (n = 12), aneurysms were detected in 5 children (18 segments).

CONCLUSION

CTCA allows comprehensive evaluation of coronary arteries in children with KD.

The influence of cardiac function on coronary arterial enhancement at coronary computed tomography angiography: A cross-sectional study

Background:

The purpose of this study was to evaluate the influence of ejection fraction (EF) on peak aortic time (PAT) and peak aortic enhancement (PAE) during coronary computed tomography angiography (CTA).

Materials and Methods:

One-hundred and twenty patients (64 men, 56 women) underwent measurement of coronary CTA with a measurement of EF within 3 months of coronary CTA. Pearson's correlation coefficient analysis was used to investigate the relationships between EF, PAT and PAE, and peak attenuation of all coronary arteries.

Results:

The range of EF was (25%–70%) (mean: 55 ± 7.7). The range of PAT and PAE of ascending aorta on bolus test was 13–31 s (mean: 19.3 ± 2) and 153–435 HU (mean: 235 ± 40.6), respectively. Mean peak attenuation of ascending aorta, right coronary artery, left coronary artery, left circumflex artery, and left anterior descending were (561 ± 119), (476 ± 109), (505 ± 108), (467 ± 113), and (473 ± 104), respectively. There was a negative correlation between EF and PAT (r = −0.266, P = 0.003); however, there was no significant correlation between EF and PAE (r = −0.027, P = 0.767). In addition, there was no significant correlation between EF and the peak attenuation of coronary arteries.

Conclusion:

PAT was related to EF, but there was no relationship between PAE and EF. One of the explanation is that the left ventricular EF used for our study was assessed with echocardiography which is used roughly estimation of EF with interval of 5%–10% and may cause confounding results.

Coronary Computed Tomography Angiography: Patient-related factors determining image quality using a second-generation 320-slice CT scanner

PURPOSE

To investigate the diagnostic confidence of Coronary Computed Tomography Angiography (CCTA) and the effect of patient-related factors on CCTA image quality using a second-generation 320-slice scanner.

METHODS AND RESULTS

200 consecutive patients (mean age 60±12years; 109 men) prospectively underwent CCTA. The mean body mass index (BMI) was 27.1±4.9kg/m(2); the median heart rate (HR) was 60.0 (interquartile range (IQR), 53.9-66.1) beats per minute (bpm). The median segment's diameter was 2.8 (IQR, 2.2-3.4) mm. For each coronary segment ≥1.5mm in diameter, two readers scored: diameter narrowing as < or ≥50%, overall diagnostic confidence and motion-related image quality, with interobserver agreement kappa-values of 0.89, 0.91 and 0.61 respectively. Seventy-nine of the 2505 evaluated segments (3.2%) had non-diagnostic image quality because of coronary calcifications (66/79; 83.5%), stent- (6/79; 7.5%), pacemaker- (2/79; 2.5%) or motion-related artifacts (5/79; 6.5%). The effect of patient-related factors on motion-related image quality was investigated by multinomial logistic regression in 181 patients with calcium score (IQR, 0-446.5). Increasing coronary diameter was the most improving image quality factor (odds ratio (OR), 1.8637; p<0.001), marginally followed by lower HR (OR, 0.9547; p<0.001) and calcium score (OR, 0.9997; p=0.04). Gender (p=0.70), age (p=0.24) and BMI (p=0.45) did not affect image quality.

CONCLUSION

Using a second-generation 320-slice scanner, CCTA diagnostic confidence is predominantly affected by coronary calcifications, whereas motion-related image quality is non-diagnostic only in exceptional cases and mainly influenced by the coronary diameter. For future developments, our study findings therefore suggest greater requirements concerning spatial resolution and calcium-related artifact removal than concerning temporal resolution, especially to improve diagnostic confidence in patient groups with smaller coronary diameters.

Effect of heart rate on the diagnostic accuracy of 256-slice computed tomography angiography in the detection of coronary artery stenosis: ROC curve analysis

The aim of the present study was to investigate the effect of heart rate (HR) on the diagnostic accuracy of 256-slice computed tomography angiography (CTA) in the detection of coronary artery stenosis. Coronary imaging was performed using a Philips 256-slice spiral CT, and receiver operating characteristic (ROC) curve analysis was conducted to evaluate the diagnostic value of 256-slice CTA in coronary artery stenosis. The HR of the research subjects in the study was within a certain range (39-107 bpm). One hundred patients suspected of coronary heart disease underwent 256-slice CTA examination. The cases were divided into three groups: Low HR (HR <75 bpm), moderate HR (75≤ HR <90 bpm) and high HR (HR ≥90 bpm). For the three groups, two observers independently assessed the image quality for all coronary segments on a four-point ordinal scale. An image quality of grades 1-3 was considered diagnostic, while grade 4 was non-diagnostic. A total of 97.76% of the images were diagnostic in the low-HR group, 96.86% in the moderate-HR group and 95.80% in the high-HR group. According to the ROC curve analysis, the specificity of CTA in diagnosing coronary artery stenosis was 98.40, 96.00 and 97.60% in the low-, moderate- and high-HR groups, respectively. In conclusion, 256-slice coronary CTA can be used to clearly show the main segments of the coronary artery and to effectively diagnose coronary artery stenosis. Within the range of HRs investigated, HR was found to have no significant effect on the diagnostic accuracy of 256-slice coronary CTA for coronary artery stenosis.

The Essentials of Cardiac Computerized Tomography

Cardiac computerized tomography (CT) has evolved from a research tool to an important diagnostic investigation in cardiology, and is now recommended in European, US, and UK guidelines. This review is designed to give the reader an overview of the current state of cardiac CT. The role of cardiac CT is multifaceted, and includes risk stratification, disease detection, coronary plaque quantification, defining congenital heart disease, planning for structural intervention, and, more recently, assessment of ischemia. This paper addresses basic principles as well as newer evidence.

Prospectively ECG-Triggered Sequential Dual-Source Coronary CT Angiography in Patients with Atrial Fibrillation: Influence of Heart Rate on Image Quality and Evaluation of Diagnostic Accuracy

Objectives

To evaluate the effects of mean heart rate (HR) and heart rate variation (HRV) on image quality and diagnostic accuracy of prospectively ECG-triggered sequential dual-source coronary CT angiography (CCTA) in patients with atrial fibrillation (AF).

Methods

Eighty-five patients (49 women, 36 men; mean age 62.1±9.5 years) with persistent AF underwent prospectively ECG-triggered sequential second-generation dual-source CCTA. Tube current and voltage were adjusted according to body mass index (BMI) and iterative reconstruction was used. Image quality of coronary segments (four-point scale) and presence of significant stenosis (>50%) were evaluated. Diagnostic accuracy was analyzed in 30 of the 85 patients who underwent additional invasive coronary angiography (ICA).

Results

Only 8 of 1102 (0.7%) segments demonstrated poor image quality. No significant impact on image quality was found for mean HR (94.9±21.8 bpm; r=0.034, p=0.758; F=0.413, p=0.663) or HRV (67.5±22.8 bpm; r=0.097, p=0.377; F=0.111, p=0.895). On per-segment analysis, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 89.7% (26/29), 99.4% (355/357), 92.9% (26/28), and 99.2% (355/358), respectively, with excellent correlation (kappa=0.91) with ICA. Mean effective dose was 3.3±1.0 mSv.

Conclusions

Prospectively ECG-triggered sequential dual-source CCTA provides diagnostic image quality and good diagnostic accuracy for detection of coronary stenosis in AF patients without significant influence by HR or HRV.

Male Gender and Arterial Hypertension are Plaque Predictors at Coronary Computed Tomography Angiography

BACKGROUND

Systemic Arterial Hypertension (SAH) is one of the main risk factors for Coronary Artery Disease (CAD), in addition to male gender. Differences in coronary artery lesions between hypertensive and normotensive individuals of both genders at the Coronary Computed Tomography Angiography (CCTA) have not been clearly determined.

OBJECTIVE

To Investigate the calcium score (CS), CAD extent and characteristics of coronary plaques at CCTA in men and women with and without SAH.

METHODS

Prospective cross-sectional study of 509 patients undergoing CCTA for CAD diagnosis and risk stratification, from November 2011 to December 2012, at Instituto de Cardiologia Dante Pazzanese. Individuals were stratified according to gender and subdivided according to the presence (HT +) or absence (HT-) of SAH.

RESULTS

HT+ women were older (62.3 ± 10.2 vs 57.8 ± 12.8, p = 0.01). As for the assessment of CAD extent, the HT+ individuals of both genders had significant CAD, although multivessel disease is more frequent in HT + men. The regression analysis for significant CAD showed that age and male gender were the determinant factors of multivessel disease and CS ≥ 100. Plaque type analysis showed that SAH was a predictive risk factor for partially calcified plaques (OR = 3.9).

CONCLUSION

Hypertensive men had multivessel disease more often than women. Male gender was a determinant factor of significant CAD, multivessel disease, CS ≥ 100 and calcified and partially calcified plaques, whereas SAH was predictive of partially calcified plaques.

Korean guidelines for the appropriate use of cardiac CT

The development of cardiac CT has provided a non-invasive alternative to echocardiography, exercise electrocardiogram, and invasive angiography and cardiac CT continues to develop at an exponential speed even now. The appropriate use of cardiac CT may lead to improvements in the medical performances of physicians and can reduce medical costs which eventually contribute to better public health. However, until now, there has been no guideline regarding the appropriate use of cardiac CT in Korea. We intend to provide guidelines for the appropriate use of cardiac CT in heart diseases based on scientific data. The purpose of this guideline is to assist clinicians and other health professionals in the use of cardiac CT for diagnosis and treatment of heart diseases, especially in patients at high risk or suspected of heart disease.

Multi-Detector Coronary CT Imaging for the Identification of Coronary Artery Stenoses in a "Real-World" Population

BACKGROUND

Multi-detector computed tomography (CT) has emerged as a modality for the non-invasive assessment of coronary artery disease (CAD). Prior studies have selected patients for evaluation and have excluded many of the “real-world” patients commonly encountered in daily practice. We compared 64-detector-CT (64-CT) to conventional coronary angiography (CA) to investigate the accuracy of 64-CT in determining significant coronary stenoses in a “real-world” clinical population.

METHODS

A total of 1,818 consecutive patients referred for 64-CT were evaluated. CT angiography was performed using the GE LightSpeed VCT (GE^® Healthcare). Forty-one patients in whom 64-CT results prompted CA investigation were further evaluated, and results of the two diagnostic modalities were compared.

RESULTS

A total of 164 coronary arteries and 410 coronary segments were evaluated in 41 patients (30 men, 11 women, age 39–85 years) who were identified by 64-CT to have significant coronary stenoses and who thereafter underwent CA. The overall per-vessel sensitivity, specificity, positive predictive value, negative predictive value, and accuracy at the 50% stenosis level were 86%, 84%, 65%, 95%, and 85%, respectively, and 77%, 93%, 61%, 97%, and 91%, respectively, in the per-segment analysis at the 50% stenosis level.

CONCLUSION

64-CT is an accurate imaging tool that allows a non-invasive assessment of significant CAD with a high diagnostic accuracy in a “real-world” population of patients. The sensitivity and specificity that we noted are not as high as those in prior reports, but we evaluated a population of patients that is typically encountered in clinical practice and therefore see more “real-world” results.

A randomized, double-blind, placebo-controlled, phase III study of the short-acting β1-adrenergic receptor blocker landiolol hydrochloride for coronary computed tomography angiography in Japanese patients with suspected ischemic cardiac disease

Objectives and Background

The objective of this study was to investigate the image quality-improving and heart rate-lowering effects of landiolol hydrochloride (a short-acting β₁-adrenergic receptor blocker) on coronary computed tomography angiography (CCTA). During CCTA, β-adrenergic receptor blockers have been commonly used to lower heart rate and improve image quality.

Methods

A total of 258 subjects suspected of having ischemic cardiac disease and requiring CCTA were randomized to either a landiolol hydrochloride 0.125 mg/kg group or placebo group to study the efficacy and safety of landiolol hydrochloride in a multicenter, double-blind, randomized parallel study. The primary endpoint was the diagnosable proportion (proportion of subjects whose coronary stenosis was diagnosable).

Results

The diagnosable proportions about the reconstruction images at mid-diastole were 68.2 and 38.2 % in the landiolol hydrochloride and placebo group, respectively, indicating significant superiority of landiolol hydrochloride over placebo (p < 0.0001). The diagnosable proportions about the optimal reconstruction images were 81.4 and 54.2 % in the landiolol hydrochloride and placebo group, respectively, indicating significant superiority of landiolol hydrochloride over placebo (p < 0.0001). The mean heart rate-lowering effect was first observed soon after administration of landiolol hydrochloride, was most marked at 3–5 min, and disappeared 30 min after completion of administration. The mean heart rate-lowering proportion at that time was −19.1 ± 8.1 % and −5.9 ± 9.7 % in the landiolol hydrochloride and placebo groups, respectively, showing a significantly higher proportion in the landiolol hydrochloride group.

Conclusions

Landiolol hydrochloride was confirmed to significantly and rapidly lower heart rate after intravenous injection, suggesting that it is a safe and useful agent for improving the image quality of CCTA.

Diagnostic accuracy of contrast-enhanced ultrasound for renal cell carcinoma: a meta-analysis

This meta-analysis aimed to identify the accuracy of contrast-enhanced ultrasonography (CEUS) for the diagnosis of renal cell carcinoma (RCC). We searched PubMed, Web of Science, Google Scholar, Cochrane Library, CISCOM, CINAHL, EBSCO, and CBM databases from inception through August 1, 2013 without language restrictions. Meta-analysis was conducted using STATA version 12.0 and Meta-Disc version 1.4 softwares. We calculated the summary statistics for sensitivity (Sen), specificity (Spe), positive and negative likelihood ratio (LR+/LR-), diagnostic odds ratio (DOR), and receiver operating characteristic (SROC) curve. Eleven studies that met all inclusion criteria were included in this meta-analysis. A total of 567 RCC patients and 313 patients with benign renal tumors were assessed. All renal lesions were histologically confirmed after CEUS. The pooled Sen was 0.88 (95 %CI = 0.85 ∼ 0.90); the pooled Spe was 0.80 (95 %CI = 0.75 ∼ 0.85). The pooled LR+ was 4.30 (95 %CI = 2.65 ∼ 6.99); the pooled negative LR- was 0.11 (95 %CI = 0.05 ∼ 0.22). The pooled DOR of CEUS in the diagnosis of RCC was 46.97 (95 % CI = 16.72 ∼ 131.97). The area under the SROC curve was 0.922 (standard error [SE] = 0.039). We found no evidence for publication bias (t = -1.00, P = 0.342). Our meta-analysis indicates that CEUS may have high diagnostic accuracy in differential diagnosis between benign and malignant renal tumors. Thus, CEUS may be a good tool for the diagnosis of RCC.

Single dose ivabradine versus intravenous metoprolol for heart rate reduction before coronary computed tomography angiography (CCTA) in patients receiving long-term calcium channel-blocker therapy

BACKGROUND

In patients with contraindication for beta-blockers who are also under long-term calcium channel-blocker therapy for any reason, ivabradine may be used as an alternative treatment to achieve the target heart rate.

PURPOSE

To assess whether single dose oral ivabradine in patients referred for coronary computed tomography angiography (CCTA) is safe and can significantly decrease heart rate compared to intravenous (i.v.) metoprolol in patients receiving long-term calcium channel-blocker therapy.

MATERIAL AND METHODS

One-hundred and twenty patients who were under calcium channel-blocker therapy referred for CCTA were randomized to premedication with single dose (15 mg) ivabradine (n = 63) or i.v. metoprolol (5-10 mg) (n = 62). Hearth rate (HR) was assessed at admission (HR1), prescan (HR2), and during CCTA scan (HR3) for all patients. Blood pressure (BP) was measured before medication (BP1) and immediately before CCTA scan (BP2).

RESULTS

Although the HR averages of two groups were not significantly different before medication (HRIv1 = 80 ± 7 bpm vs. HRβ1 = 81 ± 7 bpm; P = 0.42), significant HR reduction was observed in the ivabradine group (HRIv3 = 62 ± 7 bpm) when compared to the metoprolol group (HRβ3 = 66 ± 6 bpm; P = 0.001). Decreases in HR forivabradine (18 ± 6 bpm) was significantly higher than for metoprolol (15 ± 4 bpm; P = 0.003) without relevant side-effects. Ivabradine showed no significant effect on either systolic BP or diastolic BP (siBPIv1, 139 ± 10; siBPIv2, 138 ± 10; P = 0.260; diBPIv1, 81 ± 7; diBPIv2, 81 ± 6; P = 0.59). Nevertheless, metoprolol group demonstrated significant reduction in both SiBP and DiBP (siBPβ1, 136 ± 11; siBPβ2 130 ± 11; P < 0.001; diBPβ1, 81 ± 6; diBPβ2, 78 ± 6; P < 0.001).

CONCLUSION

Single dose ivabradine is safe and significantly more effective than i.v. metoprolol in decreasing HR in patients under calcium channel-blocker therapy.

Dual-source CT versus single-source 64-section CT angiography for coronary artery disease: A meta-analysis

AIM

To perform a meta-analysis to compare the diagnostic performance of single-source 64-section computed tomography (CT) versus dual-source CT angiography for diagnosis of coronary artery disease (CAD).

MATERIALS AND METHODS

The Cochrane Library, MEDLINE, and EMBASE were searched for relevant original papers. Inclusion criteria were (1) significant CAD defined as ≥50% reduction in luminal diameter by invasive coronary angiography as reference standard; (2) single-source 64-section CT or dual-source CT was used; (3) results were reported in absolute numbers of true-positive, false-positive, true-negative, and false-negative results or sufficiently detailed data for deriving these numbers were presented. A random-effects model was used for the meta-analysis.

RESULTS

Fifty-one papers including 3966 patients who underwent single-source 64-section CT and 2047 patients who underwent dual-source CT at a per-patient level were pooled. The diagnostic values of single-source 64-section CT versus dual-source CT were 97% versus 97% for sensitivity (p = 0.386), 78% versus 86% for specificity (p < 0.001), 90% versus 85% for positive predictive value (PPV; p < 0.001), 93% versus 97% for negative predictive value (NPV; p = 0.001), 6.8 versus 6.5 for positive likelihood ratio (p = 0.018), 0.04 versus 0.04 for negative likelihood ratio (p = 0.625), and 191.59 versus 207.37 for diagnostic odds ratio (p = 0.043), respectively.

CONCLUSION

Dual-source CT and single-source 64-section CT have similar negative likelihood ratios and, therefore, there was no significant difference in their utility to rule out CAD in intermediate-risk patients. However, compared to single-source 64-section CT, dual-source CT has significantly higher specificity, so that CT-based decisions for subsequent coronary catheter angiography are more accurate.

The diagnostic performance of coronary artery angiography with 64-MSCT and post 64-MSCT: systematic review and meta-analysis

PURPOSE

To comprehensively investigate the diagnostic performance of coronary artery angiography with 64-MDCT and post 64-MDCT.

MATERIALS AND METHODS

PubMed was searched for all published studies that evaluated coronary arteries with 64-MDCT and post 64-MDCT. The clinical diagnostic role was evaluated by applying the likelihood ratios (LRs) to calculate the post-test probability based on Bayes' theorem.

RESULTS

91 studies that met our inclusion criteria were ultimately included in the analysis. The pooled positive and negative LRs at patient level were 8.91 (95% CI, 7.53, 10.54) and 0.02 (CI, 0.01, 0.03), respectively. For studies that did not claim that non-evaluable segments were included, the pooled positive and negative LRs were 11.16 (CI, 8.90, 14.00) and 0.01 (CI, 0.01, 0.03), respectively. For studies including uninterruptable results, the diagnostic performance decreased, with the pooled positive LR 7.40 (CI, 6.00, 9.13) and negative LR 0.02 (CI, 0.01, 0.03). The areas under the summary ROC curve were 0.98 (CI, 0.97 to 0.99) for 64-MDCT and 0.96 (CI, 0.94 to 0.98) for post 64-MDCT, respectively. For references explicitly stating that the non-assessable segments were included during analysis, a post-test probability of negative results >95% and a positive post-test probability <95% could be obtained for patients with a pre-test probability of <73% for coronary artery disease (CAD). On the other hand, when the pre-test probability of CAD was >73%, the diagnostic role was reversed, with a positive post-test probability of CAD >95% and a negative post-test probability of CAD <95%.

CONCLUSION

The diagnostic performance of post 64-MDCT does not increase as compared with 64-MDCT. CTA, overall, is a test of exclusion for patients with a pre-test probability of CAD<73%, while for patients with a pre-test probability of CAD>73%, CTA is a test used to confirm the presence of CAD.

Multidetector-row computed tomography for noninvasive coronary imaging

Computed tomography (CT) permits cross-sectional imaging of the heart. Temporal and spatial resolutions of the technique have been insufficient to cover the heart without motion artefacts until the recent advent of multidetector systems with more than 16 detector rows. The modality is now suited for noninvasive imaging of the coronary arteries, producing detailed morphologic images of the entire coronary tree with upto 0.4 mm of spatial resolution, within a single short breath-hold duration. CT imaging goes beyond the delineation of the coronary lumen as provided by selective invasive angiography; the plaque burden of the coronary artery wall can be visualized directly, utilizing soft-tissue contrast and a high sensitivity even for the small calcifications that are present in hard plaque formations. Therefore, CT combines elements of catheterization angiography for lumen imaging and of intravascular ultrasound imaging for coronary wall imaging. However current CT technology is not yet able to compete with the temporal or spatial resolution of catheterization angiography nor does it provide the detailed spatial or contrast resolution of intravascular ultrasound imaging. At present, its use is therefore restricted to complementing the invasive modalities in appropriate indications. Although CT entails significantly less risk than the invasive procedures, the risks of radiation dose exposure and contrast agent application are not negligible. In the foreseeable future, if the current rate of technological advancement continues, CT may replace the invasive modalities in routine care for diagnostic purposes.

Advances in the noninvasive evaluation of coronary artery disease with multislice computed tomography

Current noninvasive detection of coronary artery disease (CAD) is based on the demonstration of ischemia using stress-rest imaging, which is an indirect way of identifying CAD by demonstration of the hemodynamic consequences, rather than direct visualization of the obstructive lesions in the coronary arteries. Multislice computed tomography (MSCT) has recently emerged as an extremely rapidly developing noninvasive imaging modality, which allows anatomical imaging of the coronary arteries or noninvasive coronary angiography. In addition, total plaque burden, plaque morphology and (to some extent) plaque constitution can be assessed by MSCT. The technique also provides information on resting left ventricular systolic function, and possibly resting perfusion. Ideally, stress function and perfusion should also be evaluated, since this would allow detection of ischemia and would complete the picture of CAD. However, this is not routinely performed, since sequential acquisitions are associated with high radiation doses and thus pose a limitation for cardiovascular applications of MSCT. It is anticipated that, with a reduction in radiation, MSCT may become an important player in the diagnostic and prognostic work-up of patients with known or suspected CAD.

256-slice CT coronary angiography: in vivo dosimetry and technique optimization

PURPOSE

This study was undertaken to compare the different acquisition protocols available in a last-generation multislice computed tomography scanner used for cardiovascular studies, with particular attention to dosimetric aspects.

MATERIALS AND METHODS

Our study compared prospective and retrospective electrocardiographic-gating techniques for cardiac imaging. For each patient, we performed in vivo dose measurements, using Gafchromic film. We compared the effective dose values estimated from the experimental measurements and the dose data reported on the CT console. Image quality was also assessed.

RESULTS

Prospective acquisition allows for major dose savings compared to retrospective acquisition (mean effective dose, 4.5 mSv with prospective acquisition versus 27.5 mSv with retrospective acquisition). The agreement between the experimental and software-based dose estimates was excellent and showed below 10% of variation of the measured dose.

CONCLUSION

In patients with regular rhythm and a heart rate lower than 75 bpm, the prospective acquisition technique ensures adequate diagnostic results and allows for significant patient dose savings.

Myocardial bridging analysis by coronary computed tomographic angiography in a Saudi population

AIM: To assess the incidence, location, morphology and clinical association of myocardial bridging in a Saudi population using coronary computed tomographic angiography (CCTA).

METHODS: A total of 350 CCTA of Saudi patients were included in this study (236 men, 114 women) with a mean age of 56.3 years. All patients were examined for appropriateness criteria of CCTA indications (typical chest pain, recent onset cardiomyopathy, left bundle branch block, etc.). The scans were retrospectively reviewed for the presence of myocardial bridging and any other pathological association.

RESULTS: Myocardial bridging was found in 89 of 350 (22.5%) patients. Most of the intramuscular segments were of the superficial type and found in the mid left anterior descending (LAD) (24.6%), followed by distal LAD (3.7%), diagonal branches (2%), ramus intermedius artery (1.4%) and obtuse marginal artery (0.8%). No myocardial bridging was detected in the right coronary or circumflex arteries. No significant differences were found between males and females (P = 0.14). Coronary artery atherosclerosis was found in 51 of 89 (57.3%) patients with MB. Atherosclerotic plaques were not detected in the intramuscular or distal segment of bridging arteries. Dynamic compression was observed in 35 (94.5%) patients with full encasement. No evidence of myocardial hypoperfusion was found in the territories supplied by the bridging arteries.

CONCLUSION: CCTA is excellent in analyzing myocardial bridging in a Saudi population and the results are comparable to other populations. However, finding the real incidence may need a large multicenter study.

Predictors of inaccurate coronary arterial stenosis assessment by CT angiography

OBJECTIVES

This study sought to investigate the clinical and imaging characteristics associated with diagnostic inaccuracy of computed tomography angiography (CTA) for detecting obstructive coronary artery disease (CAD) defined by quantitative coronary angiography (QCA).

BACKGROUND

Although diagnostic performance metrics of CTA have been reported, there are sparse data on predictors of diagnostic inaccuracy by CTA.

METHODS

The clinical characteristics of 291 patients (mean age: 59 ± 10 years; female: 25.8%) enrolled in the multicenter CorE-64 (Coronary Artery Evaluation Using 64-Row Multi-detector Computed Tomography Angiography) study were examined. Pre-defined CTA segment-level characteristics of all true-positive (N = 237), false-positive (N = 115), false-negative (FN) (N = 159), and a random subset of true-negative segments (N = 511) for ≥50% stenosis with QCA as the reference standard were blindly abstracted in a central core laboratory. Factors independently associated with corresponding levels of CTA diagnostic inaccuracies on a patient level and coronary artery segment level were determined using multivariable logistic regression models and generalized estimating equations, respectively.

RESULTS

An Agatston calcium score of ≥1 per patient (odds ratio [OR]: 5.2; 95% confidence interval [CI]: 1.1 to 24.6) and the presence of within-segment calcification (OR: 10.2; 95% CI: 5.2 to 19.8) predicted false-positive diagnoses. Conversely, absence of within-segment calcification was an independent predictor of an FN diagnosis (OR: 2.0; 95% CI: 1.2 to 3.5). Prior percutaneous revascularization was independently associated with patient-level misdiagnosis of obstructive CAD (OR: 4.2; 95% CI: 1.6 to 11.2). Specific segment characteristics on CTA, notably segment tortuosity (OR: 3.5; 95% CI: 2.4 to 5.1), smaller luminal caliber (OR: 0.48; 95% CI: 0.36 to 0.63 per 1-mm increment), and juxta-arterial vein conspicuity (OR: 2.1; 95% CI: 1.4 to 3.2), were independently associated with segment-level misdiagnoses. Attaining greater intraluminal contrast enhancement independently lowered the risk of an FN diagnosis (OR: 0.96; 95% CI: 0.94 to 0.99 per 10-Hounsfield unit increment).

CONCLUSIONS

We identified clinical and readily discernible imaging characteristics on CTA predicting inaccurate CTA diagnosis of obstructive CAD defined by QCA. Knowledge and appropriate considerations of these features may improve the diagnostic accuracy in clinical CTA interpretation. (Diagnostic Accuracy of Multi-Detector Spiral Computed Tomography Angiography Using 64 Detectors [CORE-64]; NCT00738218).

Physiologic assessment of coronary artery disease by cardiac computed tomography

Coronary artery disease (CAD) remains the leading cause of death and morbidity worldwide. To date, diagnostic evaluation of patients with suspected CAD has relied upon the use of physiologic non-invasive testing by stress electrocardiography, echocardiography, myocardial perfusion imaging (MPI) and magnetic resonance imaging. Indeed, the importance of physiologic evaluation of CAD has been highlighted by large-scale randomized trials that demonstrate the propitious benefit of an integrated anatomic-physiologic evaluation method by performing lesion-specific ischemia assessment by fractional flow reserve (FFR)-widely considered the "gold" standard for ischemia assessment-at the time of invasive angiography. Coronary CT angiography (CCTA) has emerged as an attractive non-invasive test for anatomic illustration of the coronary arteries and atherosclerotic plaque. In a series of prospective multicenter trials, CCTA has been proven as having high diagnostic performance for stenosis detection as compared to invasive angiography. Nevertheless, CCTA evaluation of obstructive stenoses is prone to overestimation of severity and further, detection of stenoses by CCTA does not reliably determine the hemodynamic significance of the visualized lesions. Recently, a series of technological innovations have advanced the possibility of CCTA to enable physiologic evaluation of CAD, thereby creating the potential of this test to provide an integrated anatomic-physiologic assessment of CAD. These advances include rest-stress MPI by CCTA as well as the use of computational fluid dynamics to non-invasively calculate FFR from a typically acquired CCTA. The purpose of this review is to summarize the most recent data addressing these 2 physiologic methods of CAD evaluation by CCTA.

Multidetector computed tomography for coronary stents imaging: high-voltage (140-kVp) prospective ECG-triggered versus standard-voltage (120-kVp) retrospective ECG-gated helical scanning

OBJECTIVE

To compare prospective electrocardiogram (ECG)-triggered high-voltage coronary computed tomography (CT) angiography (CTA; 140-kVp P-cCTA) with retrospective ECG-gated standard-voltage cCTA (120-kVp R-cCTA), in patients with coronary stents.

METHODS

Fifty-two patients with coronary stents were studied with 64-slice multidetector scanner. Ninety-three stents were analyzed: 55 with 140-kVp P-cCTA and 38 with 120-kVp R-cCTA. Image quality (IQ), diagnostic confidence (DC), in-stent assessable lumen, artificial narrowing, and effective radiation dose were compared between techniques.

RESULTS

Image quality and DC were significantly better for the 140-kVp P-cCTA in comparison with the 120-kVp R-cCTA (IQ, 1.1 ± 0.36 vs 1.7 ± 0.60, respectively; P < 0.00001. Diagnostic confidence: 1.1 ± 0.29 vs 1.5 ± 0.65 respectively; P < 0.0001). In-stent assessable lumen and artificial narrowing were comparable between the techniques. Effective dose was lower for the 140-kVp P-cCTA (6.7 ± 2.07 mSv vs 15.8 ± 6.89 mSv; P < 0.0001).

CONCLUSIONS

High voltage combined with axial prospective ECG-triggered scan improved IQ and DC in stent cCTA imaging but failed to improve the diameter of in-stent assessable lumen and to reduce the artificial narrowing compared with the 120-kVp R-cCTA. Effective dose was 60% lower for the 140-kVp P-cCTA.