Diagnostic value of 64-slice multi-detector row cardiac CTA in symptomatic patients

Comparison of coronary CT angiography and invasive coronary angiography results

INTRODUCTION

Coronary artery disease (CAD) is a leading cause of death worldwide. Accurate diagnosis and management are critical. Non-invasive imaging, such as coronary computed tomography angiography (CCTA), is vital for early diagnosis and treatment planning. This study evaluates the accuracy of CAD-Reporting and Data System (CAD-RADS) scoring and the compatibility between CCTA and invasive coronary angiography (ICA) in patients suspected of having CAD.

MATERIALS AND METHODS

From January 1, 2022 to January 15, 2024, 214 patients suspected of CAD underwent both CCTA and ICA. CCTA artifacts led to the exclusion of 32 patients and 128 vessels, leaving 586 vessels for analysis. CAD-RADS scoring categorized coronary stenosis. Diagnostic performance was measured by specificity, sensitivity, accuracy, positive and negative predictive value (NPV). Extracardiac findings were analyzed with a wide field of view (FOV) during CCTA.

RESULTS

A total of 214 patients (67.3% male, median age 56) were examined. Hypertension, smoking, calcium score, and high-risk plaques correlated with CCTA and ICA CAD-RADS scores; calcium score also related to hypertension, smoking, diabetes, and dyslipidemia (p < 0.05). CCTA showed a sensitivity of 80.8% and NPV of 90.3% for detecting stenosis of 70% or more; for 50% stenosis, sensitivity was 93.5% and NPV 92.1%. Agreement between CCTA and ICA was excellent in bypass patients; stenosis detection in stented patients had 85.7% sensitivity and 96.2% NPV.

CONCLUSION

This study highlights the importance of CAD-RADS and CCTA in CAD diagnosis and treatment planning. CCTA effectively evaluates stents and grafts, emphasizing the benefits of extracardiac findings and a wide FOV.

Role of DECT in coronary artery disease: a comparative study with ICA and SPECT

PURPOSE

Earlier imaging techniques for coronary artery disease (CAD) focused primarily on either morphological or functional assessment of CAD. However, dual-energy computed tomography (DECT) can be used to assess myocardial blood supply both morphologically and functionally. We aimed to evaluate the diagnostic accuracy of DECT in detecting morphological and functional components of CAD, using invasive coronary angiography (ICA) and single photon emission computed tomography (SPECT) as reference standards.

METHODS

Twenty-five patients with known or suspicious CAD and scheduled for ICA were investigated by DECT and SPECT. DECT was performed during the resting state using retrospective electrocardiography (ECG) gating. CT coronary angiography and perfusion images were generated from the same raw data. All patients were evaluated for significant stenosis (≥50%) on both ICA and DECT coronary angiography, and for myocardial perfusion defects on SPECT and DECT perfusion. Comparison was done between ICA and DECT coronary angiography for detection of significant stenosis and between SPECT and DECT perfusion for detecting myocardial perfusion defects.

RESULTS

Using ICA as reference standard, sensitivity, specificity, and accuracy of DECT coronary angiography in detecting ≥50% stenosis of coronary artery lumen were 81.6%, 97.8%, and 95.0%, respectively, by segment-based analysis and 92.1%, 96.1%, and 93.7%, respectively, by vessel-based analysis. Using SPECT as the reference standard, the sensitivity, specificity, and accuracy of DECT perfusion in detecting myocardial perfusion defects were 70.4%, 86.4%, and 80.6%, respectively, on per-segment analysis and 90.7%, 66.6%, and 84.7%, respectively, on per-territorial basis.

CONCLUSION

DECT accurately detected coronary artery stenosis and myocardial ischemia using ICA and SPECT as reference standards. In the same scan, DECT can accurately provide integrative imaging of coronary artery morphology and myocardial perfusion.

The Impact of the Geometric Characteristics on the Hemodynamics in the Stenotic Coronary Artery

The alterations of the hemodynamics in the coronary arteries, which result from patient-specific geometric significances are complex. The effect of the stenosis on the blood flow alteration had been wildly reported, but the combinational contribution from geometric factors required a comprehensive investigation to provide patient-specific information for diagnosis and assisting in the decision on the further treatment strategies. In the present study, we investigated the correlation between hemodynamic parameters and individual geometric factors in the patient-specific coronary arteries. Computational fluid dynamic simulations were performed on 22 patient-specific 3-dimensional coronary artery models that were reconstructed based on computed tomography angiography images. Our results showed that the increasing severity of the stenosis is associated with the increased maximum wall shear stress at the stenosis region (r = 0.752, P < 0.001). In contrast, the length of the recirculation zone has a moderate association with the curvature of the lesion segment (r = 0.505, P = 0.019) and the length of the lesions (r = 0.527, P = 0.064). Moreover, bifurcation in the coronary arteries is significantly correlated with the occurrence of recirculation, whereas the severity of distal stenosis demonstrated an effect on the alteration of the flow in the upstream bifurcation. These findings could serve as an indication for treatment planning and assist in prognosis evaluation.

A study of coronary artery variants and anomalies observed at a tertiary care armed forces hospital using 64-slice MDCT

BACKGROUND

Isolated coronary artery anomalies are usually clinically silent and mostly detected incidentally during angiography or autopsy. However, few of them may be implicated in cases of sudden cardiac death even in the absence of additional heart abnormalities. Prior knowledge of such variants and anomalies is necessary for planning various interventional procedures. Multiple detector computed tomography coronary angiography has proved a very useful non-invasive modality in this field given its superiority over conventional coronary angiography in providing detailed coronary artery anatomy.

METHODS

A retrospective review of the coronary CT angiography studies was carried out at our center between August 2014 and December 2015 with the purpose of describing the coronary artery variants and anomalies that we came across in our cohort.

RESULTS

In our cohort, about 77% (n=391) of the patients had a right dominant system while left dominant and co-dominant systems were seen in 12% (n=61) and 11% (n=56) respectively. Coronary CT angiography was successful in visualizing smaller branches, such as the conus artery (96.25%, n=489), the sinus node artery (83.07%, n=422), and the septal branches (95.27%, n=484). Coronary anomalies were observed in the 10.04% of our population (n=51). Eleven anomalies of origin and course were found.

CONCLUSION

Coronary CT angiography gives us a good understanding of the variations and anomalies of the anatomy of the coronary arteries. This can be of immense help to the clinician planning interventional procedures.

Comparison of 128-Slice Dual Source CT Coronary Angiography with Invasive Coronary Angiography

BACKGROUND

Coronary artery disease (CAD) is one of the leading cause of the morbidity and mortality in India as well as worldwide and last decade has seen a steep rise in incidence of CAD in India. Direct visualization of the coronary arteries by invasive catheterization still represents the cornerstone of the evaluation of CAD. Cardiac imaging is a challenge of 21 (st) century and is being answered by 128 slice dual source CT as it has good temporal resolution, high scanning speed as well as low radiation dose.

AIM

To assess the diagnostic accuracy of 128-slice dual source CT Cardiac Angiography in comparison with Conventional Catheter Cardiac Angiography.

MATERIALS AND METHODS

Forty patients attending the cardiology OPD with complaint of chest pain and suspected of having CAD were evaluated by CT coronary angiography and conventional invasive Catheter coronary angiography and the results were compared. All patients were checked for serum creatinine and ECG before the angiography. Computed Tomography (CT) coronary angiography was done using SIEMENS 128-slice Dual Source Flash Definition CT Scanner under either Retrospective or Prospective mode depending on the heart rate of the patient. Oral/IV beta-blocker were used whenever required.

RESULTS

Coronary arteries were assessed as per 17- segment AHA model. A total of 600/ 609 segments were evaluable in 40 suspected patients on CT coronary angiography, of which 21 were false positives and 8 were false negatives with specificity of 95.12% and sensitivity and positive predictive value of 95.26% & 88.46% respectively.

CONCLUSION

Non-invasive assessment of CAD is now possible with high accuracy on 128-slice dual source CT scanner.

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.

Contrast media volume optimization in high-pitch dual-source CT coronary angiography: feasibility study

To investigate the feasibility of contrast media (CM) volume reduction in dual-source coronary computed tomography angiography high-pitch mode without affecting coronary artery enhancement. Eighty patients were involved in a preliminary experiment with a default injection protocol (60 ml of CM). The age, BMI, test bolus (TB) enhancement peak and the CT values of coronary artery for each patient were recorded and the key factors for determining coronary artery enhancement were investigated. Based on the results of the preliminary experiment, 120 patients were involved in the main experiment with a new injection protocol. For each patient, the CT values and noise of left coronary sinus (LCS), and the distal segment of right coronary artery were measured. In the preliminary experiment, the peak enhancement of TB correlated most strongly with the HU values of coronary artery. Consequently, the new injection protocol was devised to catalog patients into four groups (30, 40, 50 and 60 ml) of CM based on their TB peak enhancement. In the main experiment, the 30 ml CM injection group whose peak attenuation of TB were the highest (30 vs. 40,50,60 ml: 323.0 ± 27.5 vs. 264.2 ± 11.9, 242.1 ± 8.8, 206.2 ± 18.2 HU, p < 0.05), obtained the highest attenuation of LCS (30 vs. 40,50,60 ml: 365.0 ± 41.2 vs. 341.8 ± 40.0, 326.9 ± 34.7, 312.5 ± 38.2 HU p < 0.05). Contrast optimization is feasible in high-pitch DSCT coronary angiography. Certain patients may receive 30 ml of CM without affecting vessel enhancement.

A meta-analysis of 64-section coronary CT angiography findings for predicting 30-day major adverse cardiac events in patients presenting with symptoms suggestive of acute coronary syndrome

RATIONALE AND OBJECTIVES

To determine the accuracy of 64-section coronary computed tomography angiography (CCTA) in predicting 30 day major adverse cardiac events (MACE) for patients presenting with symptoms concerning for acute coronary syndrome (ACS).

MATERIALS AND METHODS

Electronic databases between January 1, 2005, and May, 1, 2011, and reference lists from relevant published research articles were searched. We included studies on adult patients who presented with active symptoms suggestive of ACS, had immediate 64-section CCTA performed and were assessed for MACE at a minimum of 30 days past their initial presentation. Studies had to report or provide sufficient detail to determine sensitivity, specificity, positive predictive value, and negative predictive value in relation to MACE using a 50% diameter stenosis as cutoff criterion for coronary artery disease.

RESULTS

Nine studies were included for a total of 1559 patients studied (42.3% women, mean age 51.9 ± 10.6). Patients ranged from low to intermediate risk for ACS. All had initial inconclusive electrocardiograms and negative cardiac biomarker results. A total of 14.8% of patients had a positive CCTA result. The pooled sensitivity was 93.3% (95% CI 88.3%-96.6%), specificity was 89.9% (95% CI 88.3%-91.3%), positive predictive value was 48.1% (95% CI 42.5%-53.8%), and negative predictive value was 99.3% (95% CI 98.7%-99.6%).

CONCLUSION

Sixty-four section CCTA had a 99.3% negative predictive value in excluding MACE for 30 days after initial symptom presentation in 85.2% of our study population. Although the value of 64-section CCTA is best for identifying patients who can safely be discharged home, it is less useful for patients who have positive results.

Step-and-shoot prospectively ECG-gated vs. retrospectively ECG-gated with tube current modulation coronary CT angiography using 128-slice MDCT patients with chest pain: diagnostic performance and radiation dose

BACKGROUND

With increasing awareness for radiation exposure, the study of diagnostic accuracy of coronary CT angiography (CCTA) with low radiation dose techniques is mandatory to both radiologist and clinician.

PURPOSE

To compare diagnostic performance and effective radiation dose between step-and-shoot prospectively ECG-gated and retrospectively ECG-gated with tube current modulation (TCM) CCTA using 128-slice multidetector computed tomography (MDCT).

MATERIAL AND METHODS

We retrospectively evaluated 60 patients who underwent CCTA with either of two different low-dose techniques using 128-slice MDCT (23 patients for step-and shoot-prospectively ECG-gated and 37 patients for retrospectively ECG-gated with TCM CCTA) followed by conventional coronary angiography. All coronary arteries and all segments thereof, except anatomical variants or small size (< 1.5 mm) ones, were included in analysis.

RESULTS

In per-segment analysis, sensitivity, specificity, positive predictive value, and negative predictive value were 91/96%, 95/94%, 75/73%, and 98/99% for step-and-shoot prospectively ECG-gated and retrospectively ECG gated with TCM CCTA, respectively, relative to conventional coronary angiography. Effective radiation dose were 1.75 ± 0.83 mSv, 4.91 ± 1.71 mSv in the step-and-shoot prospectively ECG-gated and retrospectively ECG-gated with TCM CCTA groups, respectively.

CONCLUSION

The two low-radiation dose CCTA techniques using 128-slice MDCT yields comparable diagnostic performance for coronary artery disease in symptomatic patients with low heart rates.

Radiation exposure to patients in a multicenter coronary angiography trial (CORE 64)

OBJECTIVE

The objective of this study was to assess the exposure of patients to radiation for the cardiac CT acquisition protocol of the multicenter Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography (CORE 64) trial.

MATERIALS AND METHODS

An algorithm for patient dose assessment with Monte Carlo dosimetry was developed for the Aquilion 64-MDCT scanner. During the CORE 64 study, different acquisition protocols were used depending on patient size and sex; therefore, six patient models were constructed representing three men and three women in the categories of small, normal size, and obese. Organ dose and effective dose resulting from the cardiac CT protocol were assessed for these six patient models.

RESULTS

The average effective dose for coronary CT angiography (CTA) calculated according to Report 103 of the International Commission on Radiological Protection (ICRP) is 19 mSv (range, 16-26 mSv). The average effective dose for the whole cardiac CT protocol including CT scanograms, bolus tracking, and calcium scoring is slightly higher-22 mSv (range, 18-30 mSv). An average conversion factor for the calculation of effective dose from dose-length product of 0.030 mSv/mGy · cm was derived for coronary CTA.

CONCLUSION

The current methods of assessing patient dose are not well suited for cardiac CT acquisitions, and published effective dose values tend to underestimate effective dose. The effective dose of cardiac CT is approximately 25% higher when assessed according to the preferred ICRP Report 103 compared with ICRP Report 60. Underestimation of effective dose by 43% or 53% occurs in coronary CTA according to ICRP Report 103 when a conversion factor (E / DLP, where E is effective dose and DLP is dose-length product) for general chest CT of 0.017 or 0.014 mSv/mGy · cm, respectively, is used instead of 0.030 mSv/mGy · cm.

Accuracy of coronary artery stenosis detection with CT versus conventional coronary angiography compared with composite findings from both tests as an enhanced reference standard

OBJECTIVE

To prospectively compare the accuracy of coronary CT angiography (CCTA) and conventional coronary angiography (CCA) for stenosis detection using composite findings from both tests as an enhanced reference standard.

METHODS

One hundred thirteen patients underwent CCTA and CCA. Per-segment and per-patient accuracy of CCTA compared with initial CCA interpretation were determined. Angiographers were then unblinded to the CCTA results and re-evaluation of the CCA studies was performed with knowledge of CCTA findings, which was used as an enhanced reference standard to compare the diagnostic accuracy of CCTA versus CCA.

RESULTS

When using the enhanced reference standard instead of initial CCA interpretation, CCTA accuracy for identifying segments (patients) with ≥50% stenosis increased from 97.7% (96.5%) to 98.1% (98.2%), sensitivity from 90.5% (100%) to 90.8% (100%), and specificity from 98.4% (94.3%) to 98.9% (97.1%). CCTA identified six segments and two patients with stenoses ≥50% missed on initial CCA interpretation. Compared with the enhanced reference standard the accuracies of CCTA and of initial CCA interpretation were not different (p = 0.87).

CONCLUSION

CCTA compares favourably with CCA for stenosis detection. Use of a composite reference standard combining findings from both tests can control for the effect of false-negative CCA results when evaluating the accuracy of CCTA.

The diagnostic performance of multi-slice coronary computed tomographic angiography: a systematic review

BACKGROUND

The use of coronary computed tomographic angiography (CCTA) for evaluation of patients with suspected coronary artery disease (CAD) is growing rapidly, yet questions remain regarding its diagnostic accuracy and its impact on clinical decision-making and patient outcomes.

METHODS

A systematic literature review was conducted to identify studies examining (a) CCTA's diagnostic accuracy; and (b) the impact of CCTA on clinical decision-making and/or patient outcomes. Diagnostic accuracy estimates were limited to patient-based analyses of occlusion; outcome studies were eligible for inclusion if they involved patients at low-to-intermediate risk of CAD. Pooled accuracy estimates were derived using bivariate random effects models; non-diagnostic CCTA results were conservatively assumed to be false positives.

RESULTS

A total of 42 diagnostic accuracy studies and 11 patient outcome studies were identified. The pooled mean sensitivity for CCTA in primary analyses was 98% (95% CI: 96%, 99%); specificity was 85% (81%, 89%). A small number of outcome studies set primarily in the emergency department found triage of low-risk patients using CCTA produced no serious adverse outcomes and was time-saving relative to standard triage care. Outcome studies in the outpatient setting were limited to four case series that did not directly compare patient care or outcomes with those of contemporaneous patients evaluated without CCTA.

CONCLUSIONS

CCTA appears to have high diagnostic accuracy in patients with suspected CAD, but its potential impact on clinical decision-making and patient outcomes is less well-understood, particularly in non-emergent settings.

Step-and-shoot prospectively ECG-gated versus retrospectively ECG-gated with tube current modulation coronary CT angiography using the 128-slice MDCT: comparison of image quality and radiation dose

BACKGROUND

Little is known regarding image quality and the required radiation dose for step-and-shoot and retrospective coronary computed tomography angiography (CCTA) with tube current modulation (TCM) in 128-slice multidetector CT (MDCT) coronary angiography.

PURPOSE

To compare image quality and radiation dose in patients who underwent 128-slice MDCT by the step-and-shoot method with those in patients who underwent 128-slice MDCT with retrospective CCTA with TCM.

MATERIAL AND METHODS

CCTA obtained with 128-slice MDCT was retrospectively evaluated in 160 patients. Two independent reviewers separately scored the subjective image quality of the coronary artery segments (1, excellent; 4, poor) for step-and-shoot (68, mean heart rate [HR]: 59.3 ± 6.8) and retrospective CCTA with TCM (77, mean HR: 59.1 ± 9.8). Interobserver variability was calculated. Effective radiation doses of both scan techniques were calculated with dose-length product.

RESULTS

There was good agreement for quality scores of coronary artery segment images between the independent reviewers (κ = 0.72). The number of coronary artery segments that could not be evaluated was 2.85% (27 of 947) in the step-and-shoot and 1.87% (20 of 1071) in retrospective CCTA with TCM. Image quality scores were not significantly different (P > .05). Mean patient radiation dose was 63% lower for step-and-shoot (1.94 ± 0.70 mSv) than for retrospective CCTA with TCM (4.51 ± 1.18 mSv) (P < 0.0001). For patients who underwent step-and-shoot or retrospective CCTA with TCM, an average HR of 63.5 beats per minute was identified as the threshold for the prediction of non-diagnostic image quality for both protocols. There were no significant differences in the image quality of both methods between obese (body mass index [BMI] ≥ 25) and non-obese patients (BMI < 25), but radiation doses were higher in the obesity group than in the non-obesity group for both methods.

CONCLUSION

Both step-and-shoot and retrospective CCTA with TCM using 128-slice MDCT had similar subjective image quality scores, but step-and-shoot required a lower radiation dose than retrospective CCTA with TCM.

What is the optimal number of readers needed to achieve high diagnostic accuracy in coronary computed tomographic angiography? A comparison of alternate reader combinations

BACKGROUND

Coronary computed tomographic angiography (CCTA) possesses high accuracy to detect coronary artery disease (CAD), although studies have reported differences in diagnostic performance. Prior trials used different numbers of interpreters, and the optimal number to detect CAD is unknown.

OBJECTIVE

We compared the diagnostic performance of 1, 2, 3, and 5 randomly selected interpreters for CCTA.

METHODS

We evaluated 50 patients randomly selected from 2 multicenter studies with both 64-detector CCTA and invasive quantitative coronary angiography (QCA). Five blinded, experienced readers independently interpreted CCTA and assessed for obstructive CAD (≥ 50% stenosis) and high-risk CAD (left main, proximal left anterior descending, or 3-vessel stenoses). A core laboratory performed QCA. For each patient, different random combinations of readers were selected; the accuracy of 1, 2, and 5 readers was compared with 3 readers.

RESULTS

Obstructive and high-risk CAD were observed in 20 of 50 (40%) and 6 of 50 (12%) patients, respectively. With combinations of 1, 2, 3, or 5 readers, there was a range of per-patient diagnostic performance (sensitivity, 100% each; specificity, 67%-90%; accuracy, 80%-94%; P = NS), per-segment diagnostic performance (sensitivity, 67%-83%; specificity, 87%-93%; accuracy, 87%-92%; P < .001 for 1 vs 3 and 2 vs 3 readers), and detection of high-risk CAD (sensitivity, 83%-100%; specificity, 73%-80%; accuracy, 76%-82%; P = NS). The highest diagnostic accuracy was observed with 3 readers for each comparison.

CONCLUSION

The diagnostic performance of CCTA to detect obstructive or high-risk CAD is generally high irrespective of the number of readers. Consensus interpretation by ≥ 3 readers provides the highest diagnostic accuracy.

Computed tomographic coronary angiography in patients with surgically treated type A aortic dissection: preliminary results

Acute type A aortic dissection is a serious emergency with a mortality rate of up to 40% within the first 24 h when left untreated. Surgical therapy needs to be initiated promptly. Due to this urgent situation, preoperative evaluation of the coronary arteries is not routinely performed in these patients. The aim of this study was to evaluate the accuracy of 64-slice computed tomography angiography (CTA) for postoperative coronary artery assessment in these patients. Ten consecutive patients with two or more cardiovascular risk factors were prospectively enrolled. Patients had type A aortic dissection treated surgically with a supracoronary graft of the ascending aorta. Performance of CTA to exclude significant stenosis (>50% lumen narrowing) and/or coronary artery dissection was compared with quantitative coronary angiography. A total of 147 segments were evaluated. Three segments (2%) were excluded from analysis. CTA correctly assessed one of three significant stenoses in three patients and correctly excluded coronary artery disease (CAD) in six of ten patients. One patient was rated false positive. Overall accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CT for identifying coronary artery disease by segment was 98%, 33%, 99%, 50%, and 99%, respectively (P<0.05). By patient, it was 70%, 33%, 86%, 50%, and 75%, respectively. No coronary artery dissection was found. Noninvasive CTA may be a viable alternative to conventional angiography for postoperative coronary artery evaluation in patients with surgically treated type A aortic dissection and cardiovascular risk factors. An NPV of 99% should allow for reliable exclusion of CAD. Further studies with higher patient numbers are warranted.

Does clinical pretest probability influence image quality and diagnostic accuracy in dual-source coronary CT angiography?

RATIONALE AND OBJECTIVES

To prospectively evaluate the influence of the clinical pretest probability assessed by the Morise score onto image quality and diagnostic accuracy in coronary dual-source computed tomography angiography (DSCTA).

MATERIALS AND METHODS

In 61 patients, DSCTA and invasive coronary angiography were performed. Subjective image quality and accuracy for stenosis detection (>50%) of DSCTA with invasive coronary angiography as gold standard were evaluated. The influence of pretest probability onto image quality and accuracy was assessed by logistic regression and chi-square testing. Correlations of image quality and accuracy with the Morise score were determined using linear regression.

RESULTS

Thirty-eight patients were categorized into the high, 21 into the intermediate, and 2 into the low probability group. Accuracies for the detection of significant stenoses were 0.94, 0.97, and 1.00, respectively. Logistic regressions and chi-square tests showed statistically significant correlations between Morise score and image quality (P < .0001 and P < .001) and accuracy (P = .0049 and P = .027). Linear regression revealed a cutoff Morise score for a good image quality of 16 and a cutoff for a barely diagnostic image quality beyond the upper Morise scale.

CONCLUSION

Pretest probability is a weak predictor of image quality and diagnostic accuracy in coronary DSCTA. A sufficient image quality for diagnostic images can be reached with all pretest probabilities. Therefore, coronary DSCTA might be suitable also for patients with a high pretest probability.

Identification of unexpected nonatherosclerotic cardiovascular disease with coronary CT angiography

OBJECTIVES

The aim of this study was to assess, in a general cardiology cohort screened for obstructive coronary artery disease (CAD), the effectiveness and frequency with which multidetector computed tomography (MDCT) angiography unexpectedly imaged and identified other nonatherosclerotic cardiovascular diseases.

BACKGROUND

MDCT angiography is a novel imaging strategy employed primarily to diagnose CAD that, in the course of these studies, can also potentially identify other important but previously unrecognized cardiovascular abnormalities.

METHODS

Consecutive 64-slice MDCT angiography studies were obtained in 4,543 patients with suspected atherosclerotic CAD at the Minneapolis Heart Institute, over a 29-month period (2005 to 2007).

RESULTS

Nonatherosclerotic-related cardiovascular abnormalities judged to be of potential clinical relevance were identified in 201 patients (4.4%). In 50 of these patients (1.1% of 4,543) the abnormality was previously unrecognized despite other imaging studies performed in 40%. Most common among the 50 patients were: congenital coronary artery anomalies (38%; largely right coronary artery from the left aortic sinus); ascending aortic aneurysms > or = 45 mm (22%); hypertrophic cardiomyopathy with apical left ventricular (LV) wall thickening (14%); valvular heart diseases (8%), congenital heart diseases, including ventricular septal defect (6%); pulmonary embolus (6%); as well as LV noncompaction, left atrial myxoma, and LV apical aneurysm (2% each). As a consequence of MDCT angiography findings, new management strategies were instituted in 15 of 50 patients (30%), including surgical correction of coronary artery anomalies of wrong sinus origin, ascending aneurysm graft repair, thrombolytic therapy for pulmonary embolism, and myxoma resection.

CONCLUSIONS

Approximately 1% of patients undergoing MDCT angiography for suspicion of CAD proved to have otherwise unsuspected, but clinically relevant, cardiovascular abnormalities unrelated to coronary atherosclerosis. Almost one-third of these patients had cardiovascular diseases with major clinical implications for subsequent therapy. These findings underscore the value of MDCT angiography and the importance of careful assessment of scans for the recognition of a variety of cardiovascular abnormalities.

Transitioning from 16-slice to 64-slice multidetector computed tomography for the assessment of coronary artery disease: are we really making progress?

BACKGROUND

Multidetector computed tomography (MDCT) has demonstrated promise in the noninvasive evaluation of coronary artery disease.

OBJECTIVE

To systematically review the literature regarding the improved diagnostic accuracy of 64-slice MDCT.

METHODS

An EMBASE, OVID, PubMed and Cochrane Library database search was performed using the key words 'computed tomography' matched with the terms 'coronary artery' or 'coronary angiography' to identify English-language articles examining MDCT cardiac imaging. Studies that compared 16-slice or 64-slice MDCT with catheter-based coronary angiography for the detection of coronary artery disease in nonrevascularized, poststent and post-coronary artery bypass graft patients were included. Data were pooled to obtain a weighted sensitivity, specificity and diagnostic accuracy for MDCT. Negative and positive predictive values, and likelihood ratios were calculated based on sensitivity and specificity.

RESULTS

Currently, 15 studies involving 1008 patients have examined the efficacy of 64-slice MDCT in the assessment of coronary artery stenosis (more than 50% luminal narrowing). In these studies, 64-slice MDCT has demonstrated a sensitivity (89%), specificity (96%) and diagnostic accuracy (95%) similar to that of 16-slice MDCT. However, 64-slice MDCT was able to assess 5% more coronary artery segments than 16-slice MDCT. In revascularized patients, MDCT can accurately assess both bypass graft occlusion and stenosis. The 64-slice MDCT is also capable of adequately detecting in-stent restenosis. Improvements in spatial and temporal resolution with 64-slice technology have decreased the occurrence of high attenuation and motion artefacts that plagued the previous generation of MDCT scanners.

CONCLUSION

MDCT offers an accurate assessment of the coronary arteries, stented arteries and bypass grafts. The improved accuracy and safety of MDCT may reduce the need for catheter-based coronary angiography.

128-detector-row computed tomography coronary angiography evaluating coronary artery disease: who avoids cardiac catheterization?

PURPOSE

To evaluate the prevalence of significant coronary artery disease (CAD) and nondiagnostic studies in patients referred for clinically indicated coronary angiography performed by 128 multidetector computed tomography (MDCT).

METHODS

We examined patients referred for coronary computed tomography (CT) angiography for the presence of CAD. The analysis included 438 studies classified as normal, with nonsignificant CAD, with significant CAD, or nondiagnostic.

RESULTS

Of the 438 cases evaluated, 121 (27.6%) cases were reported as normal, 184 (42%) were classified as nonsignificant CAD, 92 (21%) as significant CAD, and 41 (9.3%) were inconclusive. Therefore, 69.7% of the study population most probably did not require conventional coronary angiography.

CONCLUSION

Among patients referred for computed tomography angiography (CTA) for appropriate indications, 69.6% had either normal coronary arteries or nonobstructive disease. Given the high negative predictive value of coronary CTA, these patients most likely would not require invasive coronary angiography. Selective cardiac CTA may substantially decrease unnecessary diagnostic cardiac catheterizations.

[Diagnostic accuracy of 64 row multidetector computed tomography for coronary artery disease assessment]

Due to technical advances, multidetector computed tomography (MDCT) allows evaluation of the coronary arteries and could in specific clinical indications provide a minimally invasive alternative to coronary angiography (CA). Recent technical advances combined with the availability of 64 row MDCT have significantly improved the evaluation of the native coronary arteries. However limitations remain for the evaluation of bypass grafts and stents. In this paper, we present a review the current literature on the diagnostic accuracy of 64 row MDCT in the assessment of coronary artery disease, and discuss the clinical implications and proposed indications of coronary CTA.

64-Channel cardiac computed tomography: intraobserver and interobserver variability (part 1): coronary angiography

OBJECTIVES

To assess intraobserver and interobserver variation in computed tomography coronary angiography (CTA) in 3 patient cohorts at very low, low-to-intermediate, and intermediate-to-high likelihood of coronary artery disease (CAD).

METHODS

One hundred thirty-three patients underwent 64-channel CTA. Coronary arteries were analyzed by 2 experienced blinded observers and reported as having 0%, 1% to 29%, 30% to 49%, 50% to 69%, 70% to 99%, or 100% stenosis. Intraobserver and interobserver agreement was calculated at cohort level and combined.

RESULTS

Overall intraobserver and interobserver agreement was good (kappa = 0.74 and kappa = 0.78, respectively). Segmental agreement for stenoses 50% or greater and 70% or greater was greater than 96%. Disagreements were more likely in the presence of noneccentric calcification for both intraobserver (odds ratio = 0.45 and 0.22) and interobserver (odds ratio = 0.40 and 0.10) measurements.

CONCLUSIONS

Interobserver and intraobserver variability for the detection of coronary stenoses on CTA is good and justifies routine clinical use. The presence of noneccentric calcium and mixed plaque morphology are important causes of disagreement.

Radiation dose in a "triple rule-out" coronary CT angiography protocol of emergency department patients using 64-MDCT: the impact of ECG-based tube current modulation on age, sex, and body mass index

OBJECTIVE

"Triple rule-out" coronary CT angiography (CTA) using 64-MDCT technology is a new approach for evaluating emergency department patients presenting with symptoms suggestive of acute coronary syndrome (ACS). Our objective was to evaluate the reduction in effective radiation dose through the use of tube current modulation in patients who underwent a triple rule-out coronary CTA evaluation and to document how effective radiation dose was impacted by patient age, sex, and body mass index (BMI).

MATERIALS AND METHODS

A retrospective analysis of triple rule-out coronary CTA examinations performed on a 64-MDCT scanner was ordered on a prospective cohort of 267 consecutive low- to moderate-risk emergency department patients with suspected ACS from a single university hospital between October 2006 and March 2008. Tube current modulation was generally used in patients with heart rates below 65 beats per minute during the second half of the study period as a way to reduce radiation exposure. We calculated effective radiation exposure using actual patient coronary CTA scanning parameters by age, sex, and BMI.

RESULTS

Among the 172 patients evaluated without tube current modulation, effective dose averaged (+/- SD) 18.0 +/- 5.6 mSv (range, 9.9-31.3 mSv). Of the 95 patients who underwent CTA examination with tube current modulation, effective dose was significantly lower at 8.75 +/- 2.64 mSv (range, 5.4-16.6 mSv; p < 0.0001) and image quality was better (p < 0.0001) as compared with examinations without tube current modulation. There were no significant radiation differences by patient age, but tube current modulation decreased radiation exposure by at least half. Among the studies in which tube current modulation was not used, women received less radiation than men (17.0 vs 19.5 mSv, respectively; p < 0.001). For the studies with tube current modulation, there were no radiation differences by sex. Obese patients received significantly more radiation than overweight and normal-weight patients in the non-tube current modulation groups (20.9 mSv vs 15.0 and 14.9 mSv, respectively; p < 0.0001) and in the tube current modulation groups (10.3 mSv vs 7.6 and 7.1 mSv, p < 0.0001).

CONCLUSION

The overall effective radiation dose for triple rule-out coronary CTA was reduced by more than 50% with ECG-based tube current modulation without loss of image quality. Tube current modulation should be used for triple rule-out coronary CTA examinations whenever possible.

Evaluation of a "triple rule-out" coronary CT angiography protocol: use of 64-Section CT in low-to-moderate risk emergency department patients suspected of having acute coronary syndrome

PURPOSE

To determine whether coronary computed tomographic (CT) angiography "triple rule-out" evaluation of emergency department (ED) patients presenting with symptoms suggestive of acute coronary syndrome (ACS) can help identify a subset of patients who can be discharged without adverse clinical outcomes within 30 days.

MATERIALS AND METHODS

This protocol was approved by the university institutional review board. Each patient provided written informed consent prior to inclusion. Coronary CT angiography was performed in 201 consecutive low-to-moderate risk ACS patients. A triple rule-out protocol was used to evaluate for coronary disease, pulmonary embolism, aortic dissection, and other thoracic disease. Four patients were excluded because of technical problems. The remaining subjects underwent a 30-day follow-up.

RESULTS

A disease process other than coronary atherosclerosis that explained the presenting symptoms was diagnosed in 22 (11%) of 197 patients. Clinically important noncoronary diagnoses that did not explain patient symptoms were identified in 27 (14%) of 197 additional patients. With respect to coronary artery disease, 10 patients had severe disease (>70% stenosis), 12 had moderate disease (50%-70% stenosis), 46 had mild disease (up to 50% stenosis), and 129 had no disease. No further diagnostic testing was performed in 133 (76%) of 175 of patients with no to mild coronary disease. At 30-day follow-up, the negative predictive value of coronary CT angiography with no more than mild disease was 99.4%. There were no adverse outcomes at 30 days.

CONCLUSION

Triple rule-out coronary CT angiography evaluation of low-to-moderate risk ACS patients presenting to the ED provided a noncoronary diagnosis that explained the presenting complaint in 11% of patients, suggested the presence of significant moderate-to-severe coronary disease in 11% (22 of 197) of patients, and precluded additional diagnostic cardiac testing in the majority of patients with no adverse outcomes at 30-day follow-up.

64-slice CT for diagnosis of coronary artery disease: a systematic review

PURPOSE

The purpose of this systematic review was to assess the accuracy of 64-slice CT coronary angiography for the diagnosis of coronary artery disease.

METHODS

We attempted to identify all published trials in all languages that used 64-slice CT to diagnose coronary artery disease. Results of 64-slice CT coronary angiography were compared with invasive coronary angiography or intravascular ultrasound.

RESULTS

Sensitivity of 64-slice CT for significant (> or =50%) stenosis, based on pooled data from all studies, was > or =90% in patient-based evaluations, named vessels, segments, and coronary artery bypass grafts, except the left circumflex (sensitivity 88%), distal segments (80%), and stents (88%). Specificity was 88% in patient-based evaluations, and > or =90% at individual sites. Positive predictive values for patient-based evaluations, left main coronary artery, and coronary artery bypass grafts ranged from 91% to 93%, but elsewhere ranged from 69% to 84%. Negative predictive values were 96% to 100%. Positive likelihood ratios for patient-based evaluations were 8.0 and, at specific sites, were > or =9.7. Negative likelihood ratios, except for distal segments, were <0.1.

CONCLUSION

Negative 64-slice CT reliably excluded significant coronary disease. However, the data suggest that stenoses shown on 64-slice CT require confirmation. Combining the results of 64-slice CT with a pre-CT clinical probability assessment would strengthen the diagnosis. Due to the risk of radiation-induced cancer, patients should be selected carefully for this test, and scan protocols should be optimized to minimize risk.

Direct comparison of whole-heart navigator-gated magnetic resonance coronary angiography and 40- and 64-slice multidetector row computed tomography to detect the coronary artery stenosis in patients scheduled for conventional coronary angiography

BACKGROUND

Both whole-heart magnetic resonance coronary angiography (WH-MRCA) and multidetector computed tomography (MDCT) have been proposed for the noninvasive identification of the coronary stenosis. The authors sought to directly compare the diagnostic accuracy of these noninvasive imaging techniques using the invasive quantitative coronary angiography as a reference standard.

METHODS AND RESULTS

Seventy-seven consecutive patients (56 men, 61+/-14 years) prospectively underwent WH-MRCA and 40- or 64-slice MDCT before the quantitative coronary angiography. Diagnostic accuracy of WH-MRCA and MDCT for the visual identification of >50% diameter stenosis in segments of >1.5 mm size was compared using the quantitative coronary angiography as a reference. According to the quantitative coronary angiography, 49 of 992 coronary segments >1.5 mm diameter had >50% diameter stenosis. MDCT had a higher success rate (100% versus 88%, P<0.001) and enabled identification of more segments (963 versus 726, P<0.001) than did WH-MRCA. On a per-segment basis, WH-MRCA had similar sensitivity (47/49 or 96% versus 48/49 or 98%, P=0.9) but significantly lower specificity (644/943 or 68% versus 863/943 or 92%, P<0.001) and accuracy (691/992 or 70% versus 911/992 or 92%, P<0.001) for the detection of >50% diameter stenosis than did MDCT. On a per-patient basis, the sensitivity was similar (17/17 or 100% versus 16/17 or 94%, P=0.9), but specificity (43/60 or 72% versus 53/60 or 88%, P=0.024) and diagnostic accuracy (60/77 or 78%, versus 69/77 or 90%, P=0.044) of WH-MRCA for the detection of >50% diameter stenosis were significantly lower than of MDCT.

CONCLUSIONS

Because of the higher success rate and higher number of interpretable segments, 40- or 64-slice MDCT performs better than WH-MRCA.

Sixty-four-slice computed tomography of the coronary arteries: cost-effectiveness analysis of patients presenting to the emergency department with low-risk chest pain

OBJECTIVES

The aim was to use a computer model to estimate the cost-effectiveness of 64-slice multidetector computed tomography (MDCT) of the coronary arteries in the emergency department (ED) compared to an observation unit (OU) stay plus stress electrocardiogram (ECG) or stress echocardiography for the evaluation of low-risk chest pain patients presenting to the ED.

METHODS

A decision analytic model was developed to compare health outcomes and costs that result from three different risk stratification strategies for low-risk chest pain patients in the ED: stress ECG testing after OU care, stress echocardiography after OU care, and MDCT with no OU care. Three patient populations were modeled with the prevalence of symptomatic coronary artery disease (CAD) being very low risk, 2%; low risk, 6% (base case); and moderate risk, 10%. Outcomes were measured as quality-adjusted life years (QALYs). Incremental cost-effectiveness ratios (ICERs), the ratio of change in costs of one test over another to the change in QALY, were calculated for comparisons between each strategy. Sensitivity analyses were conducted to test the robustness of the results to assumptions regarding the characteristics of the risk stratification strategies, costs, utility weights, and likelihood of events.

RESULTS

In the base case, the mean (+/- standard deviation [SD]) costs and QALYs for each risk stratification strategy were MDCT arm $2,684 (+/- $1,773 to $4,418) and 24.69 (+/- 24.54 to 24.76) QALYs, stress echocardiography arm $3,265 (+/- $2,383 to $4,836) and 24.63 (+/- 24.28 to 24.74) QALYs, and stress ECG arm $3,461 (+/- $2,533 to $4,996) and 24.59 (+/- 24.21 to 24.75) QALYs. The MDCT dominated (less costly and more effective) both OU plus stress echocardiography and OU plus stress ECG. This resulted in an ICER where the MDCT arm dominated the stress echocardiography arm (95% confidence interval [CI] = dominant to $29,738) and where MDCT dominated the ECG arm (95% CI = dominant to $7,332). The MDCT risk stratification arm also dominated stress echocardiography and stress ECG in the 2 and 10% prevalence scenarios, which demonstrated the same ICER trends as the 6% prevalence CAD base case. The thresholds where the MDCT arm remained a cost-saving strategy compared to the other risk stratification strategies were cost of MDCT, < $2,097; cost of OU care, > $1,092; prevalence of CAD, < 70%; MDCT specificity, > 65%; and a MDCT indeterminate rate, < 30%.

CONCLUSIONS

In this computer-based model analysis, the MDCT risk stratification strategy is less costly and more effective than both OU-based stress echocardiography and stress ECG risk stratification strategies in chest pain patients presenting to the ED with low to moderate prevalence of CAD.

Coronary revascularization treatment based on dual-source computed tomography

Therapy advice based on dual-source computed tomography (DSCT) in comparison with coronary angiography (CAG) was investigated and the results evaluated after 1-year follow-up. Thirty-three consecutive patients (mean age 61.9 years) underwent DSCT and CAG and were evaluated independently. In an expert reading (the “gold standard”), CAG and DSCT examinations were evaluated simultaneously by an experienced radiologist and cardiologist. Based on the presence of significant stenosis and current guidelines, therapy advice was given by all readers blinded from the results of other readings and clinical information. Patients were treated based on a multidisciplinary team evaluation including all clinical information. In comparison with the gold standard, CAG had a higher specificity (91%) and positive predictive value (PPV) (95%) compared with DSCT (82% and 91%, respectively). DSCT had a higher sensitivity (96%) and negative predictive value (NPV) (89%) compared with CAG (91% and 83%, respectively). The DSCT-based therapy advice did not lead to any patient being denied the revascularization they needed according to the multidisciplinary team evaluation. During follow-up, two patients needed additional revascularization. The high NPV for DSCT for revascularization assessment indicates that DSCT could be safely used to select patients benefiting from medical therapy only.

Initial evaluation of coronary images from 320-detector row computed tomography

PURPOSE

To evaluate image quality and contrast opacification from coronary images acquired from 320-detector row computed tomography (CT). Patient dose is estimated for prospective and retrospective ECG-gating; initial correlation between 320-slice CT and coronary catheterization is illustrated.

METHODS

Retrospective image evaluation from forty consecutive patients included subjective assessment of image quality and contrast opacification (80 ml iopamidol 370 mg I/ml followed by 40 ml saline). Region of interest opacification measurements at the ostium and at 2.5 mm diameter were used to determine the gradient of contrast opacification (defined as the proximal minus distal HU measurements) in coronary arteries imaged in a single heartbeat. Estimated effective dose was compared for prospective versus retrospective ECG-gating, two body mass index categories (30 kg/m(2) cutoff), and single versus two heartbeat acquisition. When available, CT findings were correlated with those from coronary catheterization.

RESULTS

Over 89% of arterial segments (15 segment model) had excellent image quality. The most common reason for image degradation was cardiac motion. One segment in one patient was considered unevaluable. Contrast opacification was almost universally considered excellent. The mean Hounsfield units (HU) was greater than 350; the coronary contrast opacification gradient was 30-50 HU. Patient doses were greater for retrospective ECG-gating, larger patients, and those imaged with two heartbeats. For the most common (n=25) protocol (120 kV, 400 mA, prospective ECG-gating, 60-100% phase window, 16 cm craniocaudal coverage, single heartbeat), the mean dose was 6.8+/-1.4 mSv. All CT findings were confirmed in the four patients who underwent coronary catheterization.

CONCLUSION

Initial 320-detector row coronary CT images have consistently excellent quality and iodinated contrast opacification. These patients were scanned with conservative protocols with respect to iodine load, prospective ECG-gating phase window, and craniocaudal coverage. Future work will focus on lowering contrast and radiation dose while maintaining image quality.

Prevalence of anatomical variants and coronary anomalies in 543 consecutive patients studied with 64-slice CT coronary angiography

The aim of our study was to assess the prevalence of variants and anomalies of the coronary artery tree in patients who underwent 64-slice computed tomography coronary angiography (CT-CA) for suspected or known coronary artery disease. A total of 543 patients (389 male, mean age 60.5 ± 10.9) were reviewed for coronary artery variants and anomalies including post-processing tools. The majority of segments were identified according to the American Heart Association scheme. The coronary dominance pattern results were: right, 86.6%; left, 9.2%; balanced, 4.2%. The left main coronary artery had a mean length of 112 ± 55 mm. The intermediate branch was present in the 21.9%. A variable number of diagonals (one, 25%; two, 49.7%; more than two, 24%; none, 1.3%) and marginals (one, 35.2%; two, 46.2%; more than two, 18%; none, 0.6%) was visualized. Furthermore, CT-CA may visualize smaller branches such as the conus branch artery (98%), the sinus node artery (91.6%), and the septal branches (93%). Single or associated coronary anomalies occurred in 18.4% of the patients, with the following distribution: 43 anomalies of origin and course, 68 intrinsic anomalies (59 myocardial bridging, nine aneurisms), three fistulas. In conclusion, 64-slice CT-CA provides optimal visualization of the variable and complex anatomy of coronary arteries because of the improved isotropic spatial resolution and flexible post-processing tool.

[Multidetector computed tomography coronarography: preliminary experience in real life settings]

Multidetector computed tomography coronarography (MDCT) is a promising tool, offering non invasive anatomic evaluation of coronary arteries. We relate in this article our impressions after our first two years experience.

METHODS

Retrospective study of the 328 patients who underwent MDCT examination between January 2005 and December 2006 at our community hospital. Per patient comparative analysis of the anatomical findings versus percutaneous angiography (PCA) in 61 cases.

RESULTS

Out of 328 patients 61 (18.5%) underwent PCA. In these patients we found a sensibility, specificity, positive predictive value and negative predictive value of 100%, 54%, 59% and 100% for MDCT. The main factor responsible for inconclusive vessel analysis was excessive calcification.

CONCLUSION

In routine use, MDCT enables one to rule out significant stenosis non invasively, with high sensitivity in an unselected patient population.

Measurement of coronary calcium scores by electron beam computed tomography or exercise testing as initial diagnostic tool in low-risk patients with suspected coronary artery disease

We determined the efficiency of a screening protocol based on coronary calcium scores (CCS) compared with exercise testing in patients with suspected coronary artery disease (CAD), a normal ECG and troponin levels. Three-hundred-and-four patients were enrolled in a screening protocol including CCS by electron beam computed tomography (Agatston score), and exercise testing. Decision-making was based on CCS. When CCS>or=400, coronary angiography (CAG) was recommended. When CCS<10, patients were discharged. Exercise tests were graded as positive, negative or nondiagnostic. The combined endpoint was defined as coronary event or obstructive CAD at CAG. During 12+/-4 months, CCS>or=400, 10-399 and <10 were found in 42, 103 and 159 patients and the combined endpoint occurred in 24 (57%), 14 (14%) and 0 patients (0%), respectively. In 22 patients (7%), myocardial perfusion scintigraphy was performed instead of exercise testing due to the inability to perform an exercise test. A positive, nondiagnostic and negative exercise test result was found in 37, 76 and 191 patients, and the combined endpoint occurred in 11 (30%), 15 (20%) and 12 patients (6%), respectively. Receiver-operator characteristics analysis showed that the area under the curve of 0.89 (95% CI: 0.85-0.93) for CCS was superior to 0.69 (95% CI: 0.61-0.78) for exercise testing (P<0.0001). In conclusion, measurement of CCS is an appropriate initial screening test in a well-defined low-risk population with suspected CAD.