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

Multislice computed tomography (CT) is an emerging technique for the non-invasive detection of coronary stenoses. While the diagnostic accuracy of 4-slice scanners was limited, 16-slice CT imagers showed promising results due to increased temporal and spatial resolution. These technical advances prompted us to evaluate the diagnostic performance of 64-slice CT coronary angiography in the detection of significant stenoses (defined as ≥ 50% luminal diameter reduction) versus invasive quantitative coronary angiography (QCA). Thirty-five patients with stable angina pectoris underwent CT coronary angiography performed with a 64-slice scanner (gantry rotation time 330 ms, individual detector width 0.6 mm) prior to conventional coronary angiography. Patients with heart rates >70 beats/min received 100 mg metoprolol orally. One hundred millilitres of contrast agent with an iodine concentration of 400 mgl/ml were injected at a rate of 5 ml/s into the antecubital vein. The CT scan was triggered with the bolus tracking technique. The sensitivity, specificity and the positive and negative predictive values of 64-slice CT were 99%, 96%, 78% and 99%, respectively, on a per-segment basis. The values obtained on a per-patient basis were 100%, 90%, 96% and 100%, respectively. When referral to catheterisation is questionable, CT coronary angiography may identify subjects with normal angiograms and consistently decrease the number of unnecessary invasive procedures.     

The Diagnostic Accuracy, Image Quality and Radiation Dose of 64-Slice Dual-Source CT in Daily Practice: a Single Institution's Experience

Objective

We wanted to evaluate the image quality, diagnostic accuracy and radiation exposure of 64-slice dual-source CT (DSCT) coronary angiography according to the heart rate in symptomatic patients during daily clinical practice.

Materials and Methods

We performed a retrospective search for the DSCT coronary angiography reports of 729 consecutive symptomatic patients. For the 131 patients who underwent invasive coronary angiography, the image quality, the diagnostic performance (sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV] for detecting significant stenosis ≥ 50% diameter) and the radiation exposure were evaluated. These values were compared between the groups with differing heart rates (HR): mean HR < 65 or ≥ 65 and HR variability (HRV) < 15 or ≥ 15.

Results

Among the 729 patients, the CT reports showed no stenosis or insignificant coronary artery stenosis in 72%, significant stenosis in 26% and non-diagnostic in 2%. For the 131 patients who underwent invasive coronary angiography, 95% of the patients and 97% of the segments were evaluable, and the overall per-patient/per-segment sensitivity, the perpatient/per-segment specificity, the per-patient/per-segment PPV and the per-patient/per-segment NPV were 100%/90%, 71%/98%, 95%/88% and 100%/97%, respectively. The image quality was better in the HR < 65 group than in the HR ≥ 65 group (p = 0.001), but there was no difference in diagnostic performance between the two groups. The mean effective radiation doses were lower in the HR < 65 or HRV < 15 group (p < 0.0001): 5.5 versus 6.7 mSv for the mean HR groups and 5.3 versus 9.3 mSv for the HRV groups.

Conclusion

Dual-source CT coronary angiography is a highly accurate modality in the clinical setting. Better image quality and a significant radiation reduction are being rendered in the lower HR group.     

Diagnostic accuracy of dual-source computed tomography in the diagnosis of coronary artery disease

PURPOSE: The aim of this study was to evaluate the diagnostic accuracy of dual-source computed tomography (DSCT) with reference to invasive coronary angiography in the diagnosis of coronary artery disease (CAD) on a per-patient as well as on a per-segment basis. MATERIALS AND METHODS: Thirty-five patients with known or suspected CAD underwent both DSCT (Somatom Definition, Siemens Medical Solutions) and quantitative x-ray coronary angiography (QCA). Parameters of CT acquisition were gantry rotation time 0.330 seconds (ie, temporal resolution 83 milliseconds), tube voltage 120 kV, tube current 560 mA with ECG-triggered tube current modulation and full current at 70% of the cardiac cycle for heart rates below 70 beats per minute or full current between 30% and 80% for higher and arrhythmic heart rates. The pitch was also adapted to the heart rate, ranging from 0.2 to 0.43. Volume and flow rate of contrast material (Ultravist 370, Schering AG) were adapted to the patient's body weight. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of DSCT in the detection or exclusion of significant CAD (ie, stenoses >50%) were evaluated on a per-patient and per-segment basis. RESULTS: All 35 CT angiograms were of diagnostic image quality. QCA demonstrated significant CAD in 48% (n = 17) and nonsignificant disease or normal coronary angiograms in 52% (n = 18) of the patients. Sensitivity, specificity, PPV, and NPV of DSCT on a per-patient basis were 100%, 89%, 89%, and 100%, respectively. On a per-segment basis, 473 of 481 coronary artery segments were assessable (98%). QCA demonstrated stenoses >50% in 32 segments (7%), and no disease or nonsignificant disease in 433 segments (93%). For the detection of stenoses >50% on a per-segment basis, DSCT showed a sensitivity, specificity, PPV, and NPV of 88%, 98%, 78%, and 99%, respectively. CONCLUSIONS: The comparison of coronary DSCT with QCA shows a very robust image quality and a high diagnostic accuracy in a patient-based as well as a per-segment analysis. Maximal sensitivity and NPV in the per-patient analysis show the strength of the technique in ruling out significant CAD.     

Significant coronary artery stenosis: comparison on per-patient and per-vessel or per-segment basis at 64-section CT angiography

PURPOSE: To prospectively evaluate the accuracy of 64-section computed tomographic (CT) coronary angiography for assessing significant stenosis on a global and segmental level, by using conventional coronary artery angiography as the reference standard. MATERIALS AND METHODS: This study was HIPAA compliant and had local institutional review board approval. Patients gave informed consent. Patients suspected of having coronary artery disease (CAD) underwent both conventional coronary catheter angiography and contrast material-enhanced retrospectively electrocardiographically gated 64-section multi-detector row CT of the coronary arteries. Two experienced observers analyzed all CT scans for signs of CAD (stenosis of 0%, or=50%) stenosis in CAD with an accuracy of 89%. On a per-segment and per-vessel basis, diagnostic accuracy is still impaired, primarily by limited spatial resolution.     

Diagnostic accuracy of 64-slice computed tomography coronary angiography in patients with low-to-intermediate risk

PURPOSE: Our aim was to evaluate the diagnostic accuracy of 64-slice computed tomography coronary angiography (MSCT-CA) for detecting significant stenosis (>or=50% lumen reduction) in a population of patients at low to intermediate risk. MATERIALS AND METHODS: We studied 72 patients (38 men, 34 women, mean age 53.9+/-8.0 years) with atypical or typical chest pain and stratified in the low-to intermediate risk category. MSCT-CA (Sensation 64 Cardiac, Siemens, Germany) was performed after IV administration of 100 ml of iodinated contrast material (Iomeprol 400 mgI/ml, Bracco, Italy). Two observers, blinded to the results of conventional coronary angiography (CAG), assessed the MSCT-CA scans in consensus. Diagnostic accuracy for detecting significant stenosis was calculated. RESULTS: CAG demonstrated the absence of significant disease in 70.1% of patients (51/72). No patient was excluded from MSCT-CA. There were 37 significant lesions on 1,098 available coronary segments. Sensitivity, specificity and positive and negative predictive value of MSCT-CA for detecting significant coronary artery on a per-segment basis were 100%, 98.6%, 71.2% and 100%, respectively. All patients with at least one significant lesion were correctly identified by MSCT-CA. MSCT-CA scored 15 false positives on a per-segment base, which affected only marginally the per-patient performance (only one false positive). CONCLUSIONS: We concluded that 64-slice CT-CA is a diagnostic modality with high sensitivity and negative predictive value in patients at low to intermediate risk.     

Forty-slice spiral computed tomography of the coronary arteries: assessment of image quality and diagnostic accuracy in a non-selected patient population

PURPOSE: To investigate prospectively the image quality and diagnostic accuracy of 40-slice computed tomography (CT) for the detection of hemodynamically significant coronary artery disease (CAD) in a non-selected, consecutive patient cohort. MATERIAL AND METHODS: Forty consecutive patients (28 men, 12 women) underwent both 40-slice CT and conventional invasive coronary angiography (ICA) within 10+/-7 days. The results of both methods were compared on a per-segment and per-patient basis, using ICA as the standard of reference. RESULTS: According to ICA, significant CAD was present in 30/40 patients (75%). Of a total of 545 segments, 43 segments (7.9%) could not be sufficiently evaluated by CT due to motion artifacts in 15 segments (34.9%), small vessel size and suboptimal contrast enhancement in 14 segments (32.6%), severe calcification in 10 segments (23.3%), and opacified adjacent structures such as cardiac veins in four segments (9.3%). Segment-based analysis for detection of significant stenosis >50% yielded an overall sensitivity, specificity, positive predictive value, and negative predictive value of 87%, 99%, 98%, and 95%, respectively. Restricting the assessment to clinically relevant proximal coronary segments led to an increase in sensitivity to 96%, specificity to 99%, and negative predictive value to 99%. Patient-based analysis demonstrated a high negative predictive value (91%) of CT for excluding significant CAD, even when all segments were included in the analysis. CONCLUSION: In a non-selected patient population with a high prevalence of CAD, 40-slice CT demonstrates high diagnostic accuracy in the assessment of significant CAD per patient and per segment.     

Italian multicenter, prospective study to evaluate the negative predictive value of 16- and 64-slice MDCT imaging in patients scheduled for coronary angiography (NIMISCAD-Non Invasive Multicenter Italian Study for Coronary Artery Disease)

This was a prospective, multicenter study designed to evaluate the utility of MDCT in the diagnosis of coronary artery disease (CAD) in patients scheduled for elective coronary angiography (CA) using different MDCT systems from different manufacturers. Twenty national sites prospectively enrolled 367 patients between July 2004 and June 2006. Computed tomography (CT) was performed using a standardized/optimized scan protocol for each type of MDCT system (≥16 slices) and compared with quantitative CA performed within 2 weeks of MDCT. A total of 284 patients (81%) were studied by 16-slice MDCT systems, while 66 patients (19%) by 64-slice MDCT scanners. The primary analysis was on-site/off-site evaluation of the negative predictive value (NPV) on a per-patient basis. Secondary analyses included on-site evaluation on a per-artery and per-segment basis. On-site evaluation included 327 patients (CAD prevalence 58%). NPV, positive predictive value (PPV), sensitivity, specificity, and diagnostic accuracy (DA) were 0.91 (95% CI 0.85–0.95), 0.91 (95% CI 0.86–0.95), 0.94 (95% CI 0.89–0.97), 0.88 (95% CI 0.81–0.93), and 0.91 (95% CI 0.88–0.94), respectively. Off-site analysis included 295 patients (CAD prevalence 56%). NPV, PPV, sensitivity, specificity, and DA were 0.73 (95% CI 0.65–0.79), 0.93 (95% CI 0.87–0.97), 0.73 (95% CI 0.65–0.79), 0.93 (95% CI 0.87–0.97), and 0.82 (95% CI 0.77–0.86), respectively. The results of this study demonstrate the utility of MDCT in excluding significant CAD even when conducted by centers with varying degrees of expertise and using different MDCT machines.     

Influence of heart rate on diagnostic accuracy and image quality of 16-slice CT coronary angiography: comparison of multisegment and halfscan reconstruction approaches

The lower the heart rate the better image quality in multislice computed tomography (MSCT) coronary angiography. We prospectively assessed the influence of heart rate on per-patient diagnostic accuracy and image quality of MSCT coronary angiography and compared adaptive multisegment and standard halfscan reconstruction. A consecutive cohort of 126 patients scheduled to undergo conventional coronary angiography was examined with 16-slice CT. For all heart rate groups, per-patient diagnostic accuracy was significantly higher for multisegment than halfscan reconstruction with values of 95 vs. 79% (p < 0.05, <65 bpm, 38 patients), 85 vs. 66% (p < 0.05, 65–74 bpm, 47 patients), and 78% vs. 41% (p < 0.001, >74 bpm, 41 patients). Differences in diagnostic accuracy between adjacent heart rate groups were only significant for halfscan reconstruction for the comparison between the 65–74 and >74 bpm group (p < 0.05). The vessel lengths free of motion artifacts were significantly longer with multisegment reconstruction in all heart rate groups and for all coronary arteries (p < 0.005). For noninvasive MSCT coronary angiography, both per-patient diagnostic accuracy and image quality decline with increasing heart rate, and multisegment reconstruction at high heart rates yields similar results as standard halfscan reconstruction at low heart rates.     

平均心率、心率变异性和钙化负荷对双源CT冠状动脉成像诊断准确性的影响

目的 与常规冠状动脉造影(CAG)对照,评价双源CT冠状动脉血管成像(CTCA)诊断冠状动脉狭窄性病变的准确性以及平均心率、心率变异性和钙化负荷对CTCA诊断准确性的影响.资料与方法 2006年12月至2008年9月,113例患者同时进行了CTCA与CAG.以CAG为参照,评价CTCA诊断≥50%和>75%冠状动脉狭窄性病变的准确性.按心率、心率变异性和钙化积分将患者分组,评价不同亚组CTCA的诊断准确性,对敏感性和特异性数据进行χ~2检验.结果 以患者为分析单位,CTCA诊断≥50%和>75%冠状动脉狭窄性病变的敏感性和特异性分别为94%、93.3%;88.5%、96.2%;以血管为分析单位,CTCA诊断≥50%和>75%冠状动脉狭窄性病变的敏感性和特异性分别为90.0%、98.0%;84.8%、98.5%;而以节段为分析单位,CTCA诊断≥50%和>75%冠状动脉狭窄性病变的敏感性和特异性分别为89.9%、99.5%;83.0%、99.7%.平均心率对CTCA诊断冠状动脉狭窄无明显影响,而心率变异性和钙化积分对CTCA诊断冠状动脉狭窄有影响.结论 无论是以患者、血管还是节段为分析单位,CTCA在诊断冠状动脉狭窄方面均有较高的敏感性和特异性,平均心率对CTCA诊断冠状动脉狭窄的准确性无明显影响,而心率变异性和钙化积分对CTCA诊断冠状动脉狭窄的准确性有影响.     

Impact of coronary calcium score on diagnostic accuracy of multislice computed tomography coronary angiography for detection of coronary artery disease

Background  The impact of the coronary calcium score on the diagnostic accuracy of multislice computed tomography (MSCT) to detect obstructive coronary stenoses remains controversial. Methods and Results  We examined 41 patients (mean Agatston score, 340 ± 530 [range, 0–2546]) with coronary artery disease with 16-slice MSCT and 60 patients (mean Agatston score, 446 ± 877 [range, 0–6264]) with 64-slice MSCT. MSCT scans were analyzed with invasive coronary angiography (CA) as the standard of reference. Lesions with luminal narrowing of 50% or greater were considered obstructive. In total, 9% and 2% of uninterpretable segments were excluded from analysis in patients examined with 16- and 64-slice MSCT, respectively. On a segment basis, the percentage of false-negative segments in the groups with Agatston scores of 0 to 100, 101 to 400, and greater than 400 with 16-slice MSCT were 0%, 5.3%, and 2.9% (P ± .0005), respectively; other comparisons of false-positive and false-negative segments were not significant. The sensitivity and specificity on a vessel and patient basis with 16- and 64-slice MSCT were not significantly different in different calcium score groups. Conclusions  A slight impact of coronary calcium was observed on the diagnostic accuracy of 16-slice MSCT CA on a segment basis, with no significant impact on a vessel and patient basis. No significant impact of coronary calcium was observed on the diagnostic accuracy of 64-slice MSCT CA on a segment, vessel, or patient basis. G.P. is financially supported by the Training Fellowship of the European Society of Cardiology and the Huygens Scholarship, The Netherlands. J.D.S. is financially supported by the Netherlands Heart Foundation, The Hague, The Netherlands (grant No. 2002B105).     

320层容积CT无心率(律)控制的冠状动脉血管成像在冠心病高危人群中的初步应用

目的 探讨在无心率(律)控制条件下,320层容积CT冠状动脉血管成像(VCTA)诊断冠心病高危人群冠状动脉狭窄的准确性.方法 对30例有冠心病高危因素的患者,以冠状动脉导管造影(ICA)为金标准,评价VCTA诊断冠状动脉节段狭窄率≥50%的敏感度、特异度、阳性预测值(PPV)、阴性预测值(NPV)及Youden指数;同时采用卡方检验分析心率快慢及钙化程度对2种检查方法诊断一致率的影响.结果 30例患者平均心率(73.7±15.4)次/min(bpm),420个可分析节段的平均Agatston钙化积分中位数为45.6分(OR=181).心率＜70和≥70 bpm分别显示242和169段,诊断一致率差异无统计学意义(P＞0.05);Agatston钙化积分≥100分的图像质量和诊断一致率低于Agatston钙化积分＜100分的节段,但VCTA与ICA结果仍具有良好吻合性(P＞0.05).结论 在无心率(律)控制情况下,VCTA对冠心病高危人群的冠状动脉狭窄诊断具有很高的准确性.     

64层螺旋CT冠状动脉成像与冠状动脉造影的对比研究

目的评价64层螺旋CT冠状动脉成像诊断冠状动脉狭窄的准确性。方法 50例患者先后进行64层螺旋CT冠状动脉成像和冠状动脉造影检查,以冠状动脉造影为诊断冠状动脉疾病的"金标准",比较CT冠状动脉成像的符合率,评价64层螺旋CT冠状动脉成像诊断冠心病的准确性。结果 64层螺旋CT冠状动脉成像评价冠状动脉狭窄程度大于或等于50%的敏感性为98.6%,诊断狭窄程度小于50%的敏感性为87.0%,诊断冠状动脉狭窄的特异性为92.5%,阴性预测值为97.7%。结论 64层螺旋CT冠脉成像诊断冠状动脉狭窄有很高的准确率。     

256层螺旋CT冠状动脉成像“双低”扫描的临床应用

目的：探讨256层螺旋CT低管电压、低对比剂用量（“双低”）扫描在冠状动脉疾病诊断中的应用价值。方法52例临床疑诊冠状动脉疾病于本院行256层螺旋CT前瞻性心电门控冠状动脉成像双低扫描（管电压80kV ,对比剂用量0．8ml/kg）的患者资料（A组）,均采用迭代重建算法iDose 5进行图像重建;50例行64层螺旋CT常规冠状动脉成像的患者资料作为对照组（B组）,两组患者均行传统冠状动脉血管造影（CCG ）检查。2名有经验的放射科医师按照15段分段法采用4级图像质量评分法评价两组患者的冠状动脉图像质量,并记录对比剂用量及辐射剂量,以CCG为准,评估两组冠状动脉C T成像的诊断准确率。结果所有患者均成功完成256层CT及64层CT 冠状动脉成像。A组患者共显示冠状动脉677节段,以CCG为标准,敏感度为94．5％,特异度为97．4％,阳性预测值为92．7％,阴性预测值为98．0％,诊断准确率为96．6％。B组冠脉成像患者共显示冠状动脉631节段,敏感度为89．1％,特异度为96．4％,阳性预测值为89．9％,阴性预测值为96．1％,诊断准确率为94．5％。两组患者的平均对比剂用量分别为56．8ml和82．2ml ,辐射剂量分别为1．46mSv和8．37mSv。结论256层螺旋CT低管电压冠脉成像技术结合低对比剂用量及迭代重建算法可实现冠状动脉成像的“双低”扫描,与CAG对比有很好的一致性。     

Diagnostic value of multislice computed tomography angiography in coronary artery disease: a meta-analysis

PURPOSE: To perform a meta-analysis of the diagnostic value of multislice CT (MSCT) angiography in the detection of coronary artery disease (CAD) when compared to conventional coronary angiography. MATERIALS AND METHODS: A search of PubMed and MEDLINE databases for English literature was performed. Only studies with at least 10 patients comparing MSCT angiography with conventional coronary angiography in the detection of CAD were included. Diagnostic value of MSCT angiography compared to coronary angiography was compared and analyzed at segment-, vessel- and patient-based assessment. RESULTS: 47 studies (67 comparisons) met the criteria and were included in our study. Pooled overall sensitivity, specificity and 95% confidence interval for MSCT angiography in the detection of CAD were 83% (79%, 89%), 93% (91%, 96%) at segment-based analysis; 90% (87%, 94%), 87% (80%, 93%) at vessel-based analysis; and 91% (88%, 95%), 86% (81%, 92%) at patient-based analysis, respectively. Diagnostic accuracy of MSCT angiography in evaluating assessable segments was significantly improved with 64-slice scanners when compared to that with 4- and 16-slice scanners (p<0.05). CONCLUSION: Our meta-analysis showed that MSCT angiography has potential diagnostic accuracy in the detection of CAD. Diagnostic performance of MSCT angiography has been significantly improved with the latest 64-slice CT, with resultant high qualitative and quantitative diagnostic accuracy. 16-slice CT was limited in spatial resolution which makes it difficult to perform quantitative assessment of coronary artery stenoses.     

Diagnostic accuracy of 64 multislice CT angiography in the assessment of coronary in-stent restenosis: A meta-analysis

Purpose

The aim of this study was to perform a meta-analysis of the diagnostic accuracy of 64-slice CT angiography for the detection of coronary in-stent restenosis in patients treated with coronary stents when compared to conventional coronary angiography.

Materials and methods

A search of PUBMED/MEDLINE, ProQuest and Cochrane library databases for English literature was performed. Only studies comparing 64-slice CT angiography with conventional coronary angiography for the detection of coronary in-stent restenosis (more than 50% stenosis) were included for analysis. Sensitivity and specificity estimates pooled across studies were tested using a fixed effects model.

Results

Fourteen studies met selection criteria for inclusion in the analysis. The mean value of assessable stents was 89%. Prevalence of in-stent restenosis following coronary stenting was 20% among these studies. Pooled estimates of the sensitivity and specificity of overall 64-slice CT angiography for the detection of coronary in-stent restenosis was 90% (95% CI: 86%, 94%) and 91% (95% CI: 90%, 93%), respectively, based on the evaluation of assessable stents. Diagnostic value of 64-slice CT angiography was found to decrease significantly when the analysis was performed with inclusion of nonassessable segments in five studies, with pooled sensitivity and specificity being 79% (95% CI: 68%, 88%) and 81% (95% CI: 77%, 84%). Stent diameter is the main factor affecting the diagnostic value of 64-slice CT angiography.

Conclusion

Our results showed that 64-slice CT angiography has high diagnostic value (both sensitivity and specificity) for detection of coronary in-stent restenosis based on assessable segments when compared to conventional coronary angiography.     

Rationale and design of the ViCTORY (Validation of an Intracycle CT Motion CORrection Algorithm for Diagnostic AccuracY) trial

BackgroundCoronary CT angiography (CTA) has emerged as an effective noninvasive method for direct visualization of the coronary arteries, with high diagnostic performance compared with invasive coronary angiography (ICA). However, coronary CTA is prone to artifacts, including coronary motion, which may reduce its diagnostic performance. Intracycle motion compensation algorithms (MCAs) from a combination of software and hardware techniques now allow for correction of coronary motion, but the diagnostic performance of MCAs compared with traditional coronary CTA reconstruction methods remains unexplored.MethodsViCTORY (Validation of an Intracycle CT Motion CORrection Algorithm for Diagnostic AccuracY) is a prospective international multicenter trial of 218 patients which is designed to evaluate the performance of MCAs for the diagnosis of anatomically obstructive coronary artery disease (CAD) compared with an ICA reference standard, on a per-patient, per-vessel, and per-segment basis. Patients enrolled into ViCTORY will undergo investigational coronary CTA and clinically indicated ICA and will not receive heart rate-lowering medications before coronary CTA. Coronary CTA images will be reconstructed by conventional standard methods as well as by MCAs. Blinded core laboratory interpretation will be performed for coronary CTA and ICA in an intent-to-diagnose fashion.ResultsThe primary end point of ViCTORY is the per-patient diagnostic accuracy of MCAs for the diagnosis of anatomically obstructive CAD compared with ICA. Secondary end points will include other per-patient, per-vessel, and per-segment diagnostic performance characteristics, including accuracy, sensitivity, specificity, positive predictive value, and negative predictive value. Other key secondary end points will include diagnostic interpretability, image quality, the upper heart rate threshold of utility of MCAs, and the additive value of MCAs to traditionally reconstructed coronary CTA.ConclusionViCTORY will determine whether MCAs improve the diagnosis of obstructive CAD in patients undergoing coronary CTA who are not receiving heart rate-lowering medications.     

64-slice computed tomography coronary angiography: diagnostic accuracy in the real world

PURPOSE: This study was done to evaluate the diagnostic accuracy of 64-slice computed tomography coronary angiography (CTCA) for the detection of significant coronary artery stenosis in the real clinical world. MATERIALS AND METHOD: From the CTCA database of our institution, we enrolled 145 patients (92 men, 52 women, mean age 63.4 +/- 10.2 years) with suspected coronary artery disease. All patients presented with atypical or typical chest pain and underwent CTCA and conventional coronary angiography (CA). For the CTCA scan (Sensation 64, Siemens, Germany), we administered an IV bolus of 100 ml of iodinated contrast material (Iomeprol 400 mgI/ml, Bracco, Italy). The CTCA and CA reports used to evaluate diagnostic accuracy adopted > or =50% and > or =70%, respectively, as thresholds for significant stenosis. RESULT: Eleven patients were excluded from the analysis because of the nondiagnostic quality of CTCA. The prevalence of disease demonstrated at CA was 63% (84/134). Sensitivity, specificity and positive and negative predictive values for CTCA on a per-segment, per-vessel, and per-patient basis were 75.6%, 85.1%, 97.6%; 86.9%, 81.8%, 58.0%; 48.2%, 68.1%, 79.6%; and 95.7%, 92.3%, 93.5%, respectively. Only two out of 134 eligible patients were false negative. Heart rate did not significantly influence diagnostic accuracy, whereas the absence or minimal presence of coronary calcification improved diagnostic accuracy. The positive and negative likelihood ratios at the per-patient level were 2.32 and 0.041, respectively. CONCLUSION: CTCA in the real clinical world shows a diagnostic performance lower than reported in previous validation studies. The excellent negative predictive value and negative likelihood ratio make CTCA a noninvasive gold standard for exclusion of significant coronary artery disease.     

Diagnostic accuracy of 64-slice computed tomography coronary angiography in a large population of patients without revascularisation: registry data in NSTEMI acute coronary syndrome and influence of gender and risk factors

Purpose

This study sought to evaluate the diagnostic accuracy of computed tomography coronary angiography (CTCA) for detecting significant coronary artery stenosis (??50% lumen reduction) compared with conventional coronary angiography (CAG) in non-ST-elevation myocardial infarction-acute coronary syndrome (NSTEMI-ACS) and in subgroups selected by gender and number of risk factors (RF).

Materials and methods

We selected from a population of 1,500 patients in a multicentre registry with NSTEMI-ACS who had undergone CTCA and CAG, (n=237; 187 men, mean age 63±10 years). Diagnostic accuracy and likelihood ratios (LR) of CTCA were assessed against CAG in the total population and subgroups (men, women: 0 RF = absence of RF, 1?C2 RF = presence of one or two RF, >2 RF = presence of more than two RF).

Results

The prevalence of obstructive disease was 53%. In the per-patient analysis, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CTCA were 100% (men 100%; women 100%; 0 RF 100%; 1?C2 RF 100%; >2 RF 100%), 95% (men 98%; women 50%; 0 RF NA% (NA, not assessable); 1?C2 RF 96%; >2 RF 96%), 95% (men 98%; women 91%; 0 RF 91%; 1?C2 RF 96%; >2 RF 96%), 100% (men 100%; women 100%; 0 RF NV%; 1?C2 RF 100%; >2 RF 100%), respectively. The per-segment analysis showed a reduction in PPV (ranging between 56% and 67%). The per-patient LR+ ranged between 18 and 27, whereas LR-were always 0. We observed no significant differences in diagnostic accuracy between subgroups.

Conclusions

CTCA is a reliable diagnostic modality with high sensitivity and NPV in NSTEMI-ACS patients who are not candidates for early revascularisation, regardless of gender and number of risk factors.     

Influence of intra-coronary enhancement on diagnostic accuracy with 64-slice CT coronary angiography

We assessed the effect of intra-coronary attenuation on diagnostic accuracy using 64-slice computed tomography coronary angiography (CT-CA). We enrolled 170 patients with suspected coronary artery disease who underwent conventional coronary angiography (CA) and 64-slice CT-CA (100 ml of Iomeprol 400 mg I/ml at 4 ml/s). The study population was divided into two groups (85 patients each based on median attenuation of 326 HU) based on mean arterial attenuation; group 1 with low attenuation and group 2 with high attenuation. Diagnostic accuracy for the detection of significant coronary artery stenosis was determined for both groups using CA as reference standard. Overall, 163 significant stenoses were detected in 1,030 assessable coronary artery segments in group 1 compared with 160 significant stenoses in 1,020 assessable segments in group 2. The average intra-coronary attenuation was significantly (P < 0.05) higher for group 2 (388 ± 46 HU) compared with group 1 (291 ± 33 HU). The corresponding sensitivity and specificity values for detection of significant coronary artery stenosis were higher for group 2 (96.3% and 97.6%, respectively) than for group 1 (82.8% and 93.2%, respectively) and were more marked in distal coronary segments than in proximal segments. Higher intra-coronary attenuation on CT-CA results in greater diagnostic accuracy for detection of coronary artery stenosis.     

The accuracy of coronary CT angiography in patients with coronary calcium score above 1000 Agatston Units: Comparison with quantitative coronary angiography

BackgroundHigh amounts of coronary artery calcium (CAC) pose challenges in interpretation of coronary CT angiography (CCTA). The accuracy of stenosis assessment by CCTA in patients with very extensive CAC is uncertain.MethodsRetrospective study was performed including patients who underwent clinically directed CCTA with CAC score >1000 and invasive coronary angiography within 90 days. Segmental stenosis on CCTA was graded by visual inspection with two-observer consensus using categories of 0%, 1–24%, 25–49%, 50–69%, 70–99%, 100% stenosis, or uninterpretable. Blinded quantitative coronary angiography (QCA) was performed on all segments with stenosis ≥25% by CCTA. The primary outcome was vessel-based agreement between CCTA and QCA, using significant stenosis defined by diameter stenosis ≥70%. Secondary analyses on a per-patient basis and inclusive of uninterpretable segments were performed.Results726 segments with stenosis ≥25% in 346 vessels within 119 patients were analyzed. Median coronary calcium score was 1616 (1221–2118). CCTA identification of QCA-based stenosis resulted in a per-vessel sensitivity of 79%, specificity of 75%, positive predictive value (PPV) of 45%, negative predictive value (NPV) of 93%, and accuracy 76% (68 false positive and 15 false negative). Per-patient analysis had sensitivity 94%, specificity 55%, PPV 63%, NPV 92%, and accuracy 72% (30 false-positive and 3 false-negative). Inclusion of uninterpretable segments had variable effect on sensitivity and specificity, depending on whether they are considered as significant or non-significant stenosis.ConclusionsIn patients with very extensive CAC (>1000 Agatston units), CCTA retained a negative predictive value ​> ​90% to identify lack of significant stenosis on a per-vessel and per-patient level, but frequently overestimated stenosis.