CT angiography after coronary artery bypass graft surgery

CT angiography is an emerging technique for the noninvasive assessment of coronary artery disease. The diagnostic performance of different generation CT scanners has been investigated for the detection of significant stenosis (≥ 50% lumen diameter reduction) in patients after coronary artery bypass surgery (CABG). The temporal and spatial resolution of CT scanners are important determinants for reliable evaluation of bypass grafts and native coronary arteries. Important drawbacks of 64-slice CT angiography remain the evaluation of severely calcified native coronary segments and distal graft anastomosis site. Future developments in the latest CT scanners head toward the use of wider detectors and improved coverage, which may be relevant in post-CABG patients. Despite technical advances, the role of CT angiography in the follow-up of patients after bypass surgery has not yet been established.     

40层螺旋CT对冠状动脉成像与冠状动脉造影的对比研究

目的 研究40层螺旋CT冠状动脉成像对冠状动脉疾病的诊断价值.方法 搜集79例可疑或已确诊为冠心病的患者进行40层螺旋CT扫描和常规冠状动脉造影,然后对2种检查方法的结果进行对比分析.结果 79例患者共有711个冠状动脉节段,其中675个（94.94%）可用于评价,结果显示40层螺旋CT诊断冠状动脉病变的敏感性为88.04%,特异性为91.08%,阳性预测值为77.47%,阴性预测值为93.56%.对冠状动脉〉50%狭窄的检出准确率为90.66%.结论 40层螺旋CT对冠心病的诊断及病变程度的评估具有较高的准确性、特异性和敏感性,可用于冠心病的初步筛选.     

64排螺旋CT冠状动脉造影与传统冠状动脉造影的对照研究

目的探讨64排螺旋CT冠状动脉造影（computed tomography coronary angiography, CTCA）,,对冠状动脉疾病的诊断价值。方法56例确诊或怀疑为冠心病的患者均行64排螺旋CT冠状动脉成像和传统冠状动脉造影（conventional coro-nary angiography,CCA）检查,并以CCA的诊断结果作为金标准,采用美国心脏协会冠状动脉改良分段法,分析共825个冠状动脉节段CTCA图像质量及其对冠状动脉狭窄的显示情况,得出CTCA诊断有意义病变（冠状动脉狭窄≥50％）fl＇,J正确性,并分析影响CTCA图像质量的主要因素。结果798个冠状动脉节段图像可以满足诊断要求,12个节段中因运动伪影或15个节段管壁严重钙化无法对血管腔进行评估。64排螺旋CT冠状动脉成像诊断≥50％狭窄总的敏感性、特异性、阳性预测值、阴性预测值、准确性分别为88．1％、97．8％、89．9％、97．4％和96％。影响图像质量主要因素为快心率、严重钙化。结论64排螺旋CT冠状动脉成像图像质量高,对冠状动脉疾病的诊断十分准确,可作为一种简便易行、安全可靠的无创性筛查冠心病的有效方法。     

The Prognostic Value of Coronary CT Angiography

Coronary CT angiography has gained increasingly widespread acceptance as a highly accurate method for the diagnosis of coronary artery disease. Beyond its usefulness as a diagnostic test to identify coronary artery stenoses in appropriately selected patients, multiple studies have consistently demonstrated that the extent and severity of coronary atherosclerosis visualized using coronary CT angiography conveys robust prognostic information. The majority of studies to date examining clinical outcomes following coronary CT angiography have documented coronary artery disease either as the presence of any coronary plaque or through the number of vessels with ≥50% (obstructive) stenosis. In the future, advanced, semi-quantitative measures of coronary atherosclerotic disease burden, plaque morphology, and composition may provide additional prognostic information. It is imperative that patients undergoing coronary CT angiography and their providers understand the prognostic information inherent to modern coronary CT angiography so that the maximal yield may be realized. Herein, we review the currently available prognostic studies of coronary CT angiography.     

Non-invasive diagnosis of in stent stenosis by stress 99m technetium tetrofosmin myocardial perfusion imaging

Background The aim of this study was to assess the accuracy of stress 99m technetium tetrofosmin myocardial perfusion imaging for the diagnosis of in stent stenosis (ISS).Methods We studied 72 patients who underwent exercise or dobutamine stress 99m technetium tetrofosmin imaging, 0.9±0.5 years after percutaneous coronary interventions in which stents were deployed. Coronary angiography was performed within 3 months of the stress test. ISS was defined as ≥50% stenosis in a coronary segment with previous stenting. Significant coronary artery disease (CAD) was defined as ≥50% stenosis within or outside the stented coronary segment.Results The stent was deployed in 1 coronary artery in 52 patients, and in 2 coronary arteries in 20 patients (a total of 92 detected in 42 (58%) patients (51 stents). Reversible perfusion abnormalities were present in 34 of patients with ISS (sensitivity=81%, CI 70–94). Regional sensitivity for diagnosis of stenosis per stent was 76% (CI 65–88), specificity was 83% (CI 71–94) and accuracy was 79% (CI 69–85). Reversible perfusion abnormalities were detected in ≥2 vascular distributions in 15 of 22 patients with multi-vessel CAD and in 5 of 50 patients without (sensitivity for identifying multivessel CAD=68%, CI 50–89; specificity=90%, CI 82–98; and accuracy=83%, CI 75–90).Conclusion Stress 99m technetium tetrofosmin myocardial perfusion imaging is a useful non-invasive technique for the diagnosis of in stent stenosis and extent of CAD in patients with previous percutanenous coronary artery interventions.     

Comparison of dual-source ct coronary angiography and conventional coronary angiography for detecting coronary artery disease

To evaluate the diagnostic accuracy of dual-source CT coronary angiography for detecting coronary artery stenosis. From February 2008 to January 2009, dual-source CT coronary CT angiography (DSCT-CCTA) and conventional coronary angiography (CAG) were both performed in 84 patients who had either clinical symptoms or a high risk of coronary artery disease. The diagnostic accuracy of DSCT-CCTA was evaluated by comparing it with that of CAG, which was regarded as the gold standard for making the diagnosis of coronary artery disease. Occlusion or stenosis of various degrees was revealed by DSCT-CCTA in 244 segments of 84 patients. Compared to CAG, segment-based sensitivity, specificity, positive predictive value and negative predictive value of DSCT-CCTA were 97.4, 97.8, 92.2 and 100%, respectively. The diagnostic accuracy of DSCT-CCTA for the detection of coronary artery stenosis was 96.5%. The paired χ2 tests revealed no significant difference between DSCT-CCTA and CAG for making the diagnosis of coronary artery disease (P = 0.076). The diagnostic performance of DSCT-CCTA is generally as accurate as that of CAG. Thus, DSCT-CCTA is a reliable non-invasive method for detecting coronary artery stenosis.     

应用全模型迭代重建技术的低剂量冠脉CTA在疑似冠心病患者中诊断价值的初步研究

目的:评估应用全模型迭代重建(IMR)技术的低剂量冠脉CTA显示冠状动脉的图像质量及其对疑似冠心病患者冠脉狭窄的诊断价值。方法:回顾分析我院疑似冠心病并接受冠脉CTA及冠状动脉造影(CAG)检查的患者80例。采用4分法对冠脉各主支进行主观质量评分。以CAG显示冠脉管腔直径缩小超过50%为阳性标准,分别在冠脉节段、主支水平分析冠脉CTA诊断冠脉狭窄的灵敏度、特异度、阳性预测值(PPV)、阴性预测值(NPV)及准确度,将患者按Agaston积分分成两组(A组<400,B组≥400),比较两组间诊断效能的差异。结果:在节段水平上,98.1%的冠脉图像质量合格,冠脉CTA诊断冠脉狭窄的灵敏度、特异度、PPV、NPV及准确度分别为93.2%、98.0%、91.3%、98.4%、97.1%;在主支水平上,96.6%的冠脉图像质量合格,冠脉CTA诊断冠脉狭窄的灵敏度、特异度、PPV、NPV及准确度分别为84.6%、93.0%、88.9%、90.1%、89.6%;A、B两组之间在特异度、PPV和准确度上存在显著差异(99.2%&91.8%,95.7%&84.2%,97.9%&93.7%,P<0.05)。结论:应用IMR技术的低剂量冠脉CTA检查可获得满意的图像质量,对冠脉狭窄具有较高的诊断准确性,但对严重钙化的血管节段的诊断尚有局限性。     

Multislice computed tomography coronary angiography in patients admitted with a suspected acute coronary syndrome

Objectives The aim of this prospective clinical study was to assess the accuracy and clinical relevance of multislice computed tomography coronary angiography (MSCTCA) in patients presenting with acute chest pain. Background Multislice computed tomography coronary angiography has shown ability to detect accurately coronary artery disease (CAD) in selected elective patient groups. Methods One hundred and twenty patients presenting with acute chest pain (<24 h) underwent MSCTCA (Siemens Sensation 16) before a scheduled inpatient conventional coronary angiogram (CCA). Exclusion criteria included patients with STEMI, non-sinus rhythm, contraindication to β blockers and renal impairment. Blinded visual assessment of MSCTCA to detect CAD was performed on an 11-segment model. The accuracy of MSCTCA was compared to CCA to detect significant stenoses (≥50%). Results One hundred and thirteen patients underwent both investigations. The prevalence of significant CAD was 74%. 1,243 native segments were assessed by MSCTCA. The overall ability of MSCTCA to detect the presence of ≥1 significant stenosis in all native segments had a sensitivity of 92% (95%CI 83–97%), specificity of 55% (95%CI 35–74%), positive predictive value of 86% (95%CI 76–93%) and negative predictive value of 70% (95%CI 47–87%). 22% of all segments (mostly distal) were non-analyzable. Coronary calcification was a major cause of false positivity. Conclusion In a prospective study of unselected patients presenting with acute chest pain, the diagnostic accuracy of 16-slice CT coronary angiography was moderate and less than reported from studies in elective patients. The clinical relevance of this technology to screen patients with acute chest pain is limited.

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Condensed Abstract Multislice CT coronary angiography (MSCTCA) and conventional coronary angiography (CCA) were used to assess 120 patients presenting with acute chest pain. MSCTCA was compared to CCA to detect significant stenoses (≥50%). In 113 directly comparable patients MSCTCA had a sensitivity of 92% (95%CI 83–97%) and specificity of 55% (95%CI 35–74%) to detect the presence of ≥1 significant stenosis in all native segments. In this patient cohort with a high prevalence of coronary disease and coronary calcification, the accuracy and clinical relevance of 16 slice MSCTCA to screen and risk stratify patients with acute chest pain is limited.

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多层螺旋CT冠状动脉造影的成像技术及临床应用价值

目的:分析多层螺旋CT冠状动脉造影的成像技术及价值。方法:将2018年1月-2019年1月期间我院收治的100例疑似冠心病患者作为研究对象,患者均给予冠状动脉造影检查和多层螺旋CT(MSCT)检查,对比两种检查方式的效果。结果:(1)对比两种诊断方式准确率:冠状动脉造影检查结果显示100例患者均为冠心病,诊断准确率为100%,MSCT结果显示98例患者为冠心病,诊断准确率为98%,组间数据无统计学意义(P>0.05);(2)多层螺旋CT显示情况分析:对于冠状动脉1~3级分支MSCT均能够清晰显示,但在4级冠状动脉分支显示效果较差。结论:MSCT能够清晰显示冠状动脉1~3级和4级部分分支,对冠心病患者具有较高的诊断准确率,使用价值高,值得推广。     

Diagnostic value of coronary CT angiography with prospective ECG-gating in the diagnosis of coronary artery disease: a systematic review and meta-analysis

To perform a systematic review and meta-analysis of the diagnostic value of prospective ECG-gating coronary CT angiography in the diagnosis of coronary artery disease. A search of biomedical databases for English literature was performed to identify studies investigating the diagnostic value of 64- or more slice CT angiography with use of prospective ECG-gating in the diagnosis of coronary artery disease. Sensitivity, specificity, positive and negative predictive value estimates pooled across studies were tested using a fixed effects model. Fourteen studies met selection criteria for inclusion in the analysis. Pooled estimates and 95% confidence interval (CI) of sensitivity, specificity, positive and negative predictive value of prospective ECG-gating coronary CT angiography for diagnosis of significant coronary stenosis were 99% (95% CI: 98, 100%), 91% (95% CI: 88, 94%), 94% (95% CI: 91, 96%) and 99% (95% CI: 97, 100%), according to the patient-based assessment. The mean values of sensitivity, specificity, positive and negative predictive value of prospective ECG-gating coronary CT angiography were 95% (95% CI: 93, 96%), 95% (95% CI: 93, 95%), 88% (95% CI: 86, 90%), and 98% (95% CI: 97, 98%), according to vessel-based assessment; 92% (95% CI: 90, 93%), 97% (95% CI: 97, 98%), 84% (95% CI: 82, 86%), 99% (95% CI: 99, 99%), according to segment-based assessment, respectively. The mean effective dose was 3.3 mSv (95% CI: 2.3, 4.1 mSv) for the prospective ECG-gating coronary CT angiography. This analysis shows that for a predominantly male population with a high disease prevalence the use of coronary CT angiography with prospective ECG gating allows for a reduced radiation exposure without a sacrifice in diagnostic efficacy.     

64层螺旋CT诊断冠状动脉病变的临床价值

目的：通过对64排螺旋CT（MSCT）冠状动脉造影与选择性冠状动脉造影检测冠状动脉病变（冠状动脉狭窄≥50%）的对比分析,探讨64层螺旋CT评估冠状动脉病变诊断的准确性。方法：回顾性收集2007年12月～2008年10月于我院同期接受64层螺旋CT冠状动脉成像和常规经皮冠脉造影的112位冠心病患者的影像资料,以常规冠脉造影为参考标准,对2种检查方法的结果进行对比分析,评估64层螺旋CT冠脉造影对冠状动脉病变诊断的准确性。结果：按常规冠脉造影计算,112例患者共发现374处病变用于评价,MSCT造影检测冠脉病变总的准确性为90.6%,假阳性率和假阴性率分别为4.3%和5.1%;其中MSCT检测为假阴性均发生在左回旋支和右冠远段,假阳性均为冠状动脉伴有钙化。结论：64排螺CT冠状动脉造影检测冠状动脉病变诊断的准确性较高,但血管解剖和冠状动脉钙化可能会影响其对冠状动脉病变的评价和检测。     

Economic Considerations for Coronary CT Angiography

In recent years, coronary CT angiography (CCTA) has emerged has a noninvasive anatomic imaging modality that demonstrates high diagnostic performance to detect and exclude high-grade coronary artery stenosis. Proponents of CCTA have advocated its use as an effective alternative to functional stress imaging, while critics have maintained that the benefits of CCTA use remain unproven and may promote unnecessary “layering” of imaging studies on top of conventional stress testing. In this review, we consider the clinical and economic data related to CCTA to date, and suggest future studies that may clarify the role of CCTA in daily clinical evaluation of patients with suspected or known coronary artery disease.     

钙化对冠脉疾病64层螺旋CT诊断的影响研究

目的：评价64层螺旋CT（64SCT）在冠心病诊断中的应用价值及钙化积分对其检测的影响。方法：对72例疑似或确诊的冠心病患者进行64层螺旋CT检查,同期行选择性冠状动脉造影（ICA）。对两种方法评价冠状动脉结果进行对照研究。结果：72例冠状动脉造影可评估率为97．3％。与ICA对照分析,评价冠状动脉狭窄的敏感性、特异性、准确率、阳性预测值、阴性预测值分别为97．77％,93．74％,94．85％,85．60％和99．10％。钙化积分按节段分组低至高分组,敏感性分别为98．99％,98．61％,94．44％;特异性为95．51％,93．66％,90．78％。结论：64层螺旋CT成像可作为无创检查诊断的可靠方法,钙化积分越高则诊断的敏感性及特异性越低。     

多层螺旋CT冠状动脉成像的应用研究

目的探讨16层CT冠状动脉成像的应用价值.方法 146例患者行16层CT冠状动脉成像,评价图像质量及狭窄程度.其中33例行常规冠状动脉造影作对照.结果 1 262节段能满足管腔评价,270个节段不能满足管腔的评价.常规造影显示正常或轻度狭窄、中度狭窄的节段,CT有89.6%的节段与其分级一致;显示重度狭窄的节段,CT有90.9%的节段与其分级一致.结论 16层CT冠状动脉成像是一种无创、简便优良的检查方法,显示有临床意义的冠状动脉狭窄(>50%)的准确性很高,对桥血管及冠脉支架术后复查具有优良价值.     

Subtraction Coronary CT Angiography for the Evaluation of Severely Calcified Lesions Using a 320-Detector Row Scanner

One of the major challenges in coronary computed tomography (CT) is the presence of severe calcification, which may interfere with the assessment of lesions and may reduce diagnostic accuracy. However, such calcifications may potentially be eliminated by subtracting precontrast CT image data from contrast-enhanced coronary CT angiography data. Such examinations require perfect alignment and can be performed in two ways: 1) the “single breath-hold method,” in which both precontrast and postcontrast CT data are acquired during a breath-hold, and 2) the “two breath-hold method,” in which the calcium scoring data are used as the precontrast CT data. Misregistration artifacts must be corrected manually based on visual assessment, which results in long image processing times. Although a number of challenges remain to be overcome, subtraction coronary CT angiography might improve the diagnostic accuracy of coronary CT angiography in patients with severe calcification in the future.     

Diagnostic accuracy of 320-row computed tomography as compared with invasive coronary angiography in unselected, consecutive patients with suspected coronary artery disease

Noninvasive coronary angiography with multislice computed tomography (CT) scanners is feasible with high sensitivity and negative predictive value. The radiation exposure associated with this technique, however, is high and concerns in the widespread use of CT have arisen. We evaluated the diagnostic accuracy of coronary angiography using 320-row CT, which avoids exposure-intensive overscanning and overranging. We prospectively studied 118 unselected consecutive patients with suspected coronary artery disease (CAD) referred for invasive coronary angiography (ICA). All patients had 320-row CT within 1 week of ICA, which, together with quantitative analysis, served as the reference standard. Of the 65 out of 118 patients who were diagnosed as having CAD by ICA, 64 (98 %) were correctly identified at 320-row CT. Noteworthy, 320-row CT correctly detected CAD in 3 patients with atrial fibrillation and ruled out the disease in the other 8 patients. From 151 significant coronary stenoses detected on ICA, 137 (91 %) were correctly identified with 320-row CT. In the per-patient analysis, sensitivity and specificity of 320-row CT were 98 and 91 %, respectively. In the per-vessel analysis, sensitivity and specificity of 320-row CT were 93 and 95 %, respectively. In the per segment analysis, sensitivity and specificity of 320-row CT were 91 and 99 %, respectively. Diameter stenosis determined with the use of CT showed good correlation with ICA (P < 0.001, R = 0.81) without significant underestimation or overestimation (?3.1 ± 24.4 %; P = 0.08). Comparison of CT with ICA revealed a significantly smaller effective radiation dose (3.1 ± 2.3 vs. 6.5 ± 4.2 mSv; P < 0.05) and amount of contrast agent required (99 ± 51 vs. 65 ± 42 ml, P < 0.05) for 320 row CT. The present study in an unselected population including patients with atrial fibrillation demonstrates that 320-row CT may significantly reduce the radiation dose and amount of contrast agent required compared with ICA while maintaining a very high diagnostic accuracy.     

Myocardial ischemia detection with single-phase CT perfusion in symptomatic patients using high-pitch helical image acquisition technique

Coronary CT angiography (CCTA) suffers from a reduced diagnostic accuracy in patients with heavily calcified coronary arteries or prior myocardial revascularisation due to artefacts caused by calcifications and stent material. CT myocardial perfusion imaging (CTMPI) yields high potential for the detection of myocardial ischemia and might help to overcome the above mentioned limitations. We analysed CT single-phase perfusion using high-pitch helical image acquisition technique in patients with prior myocardial revascularisation. Thirty-six patients with an indication for invasive coronary angiography (28 with coronary stents, 2 with coronary artery bypass grafts and 6 with both) were included in this prospective study at two study sites. All patients were examined on a 2nd generation dual-source CT system. Stress CT images were obtained using a prospectively ECG-triggered single-phase high-pitch helical image acquisition technique. During stress the tracer for myocardial perfusion (MP) SPECT imaging was administered. Rest CT images were acquired using prospectively ECG-triggered sequential CT. MP-SPECT imaging and invasive coronary angiography served as standard of reference. In this heavily diseased patient cohort CCTA alone showed a low overall diagnostic accuracy for detection of hemodynamically relevant coronary artery stenosis of only 31% on a per-patient base and 60% on a per-vessel base. Combining CCTA and CTMPI allowed for a significantly higher overall diagnostic accuracy of 78% on a per-patient base and 92% on a per-vessel base (p?<?0.001). Mean radiation dose for stress CT scans was 0.9 mSv, mean radiation dose for rest CT scans was 5.0 mSv. In symptomatic patients with known coronary artery disease and prior myocardial revascularization combining CCTA and CTMPI showed significantly higher diagnostic accuracy in detection of hemodynamically significant coronary artery stenosis when compared to CCTA alone.     

Responsible Use of Computed Tomography in the Evaluation of Coronary Artery Disease and Chest Pain

Many options are available to clinicians for the noninvasive evaluation of the cardiovascular system and patient concerns about chest discomfort. Cardiac computed tomography (CT) is a rapidly advancing field of noninvasive imaging. Computed tomography incorporates coronary artery calcium scoring, coronary angiography, ventricular functional analysis, and information about noncardiac thoracic anatomy. We searched the PubMed database and Google from inception to September 2009 for resources on the accuracy, risk, and predictive capacity of coronary artery calcium scoring and CT coronary angiography and have reviewed them herein. Cardiac CT provides diagnostic information comparable to echocardiography, nuclear myocardial perfusion imaging, positron emission tomography, and magnetic resonance imaging. A cardiac CT study can be completed in minutes. In patients with a nondiagnostic stress test result, cardiac CT can preclude the need for invasive angiography. Prognostic information portends excellent outcomes in patients with normal study results. Use of cardiac CT can reduce health care costs and length of emergency department stays for patients with chest pain. Cardiac CT examination provides clinically relevant information at a radiation dose similar to well-established technologies, such as nuclear myocardial perfusion imaging. Advances in technique can reduce radiation dose by 90%. With appropriate patient selection, cardiac CT can accurately diagnose heart disease, markedly decrease health care costs, and reliably predict clinical outcomes.CAC = coronary artery calcium; CAD = coronary artery disease; CT = computed tomography; CTA = coronary computed tomographic angiography; EBCT = electron beam CT; ED = emergency department; ICA = invasive coronary angiography; MDCT = multidetector helical CT; MI = myocardial infarction; MPI = myocardial perfusion imaging; NPV = negative predictive value; PPV = positive predictive valueCardiac computed tomography (CT) is a rapidly evolving technology for the noninvasive evaluation of the cardiovascular system. Numerous potential roles for cardiac CT have been developed recently, such as investigating anomalous coronary arteries, evaluating for pulmonary vein stenoses, and preparing for repeated coronary artery bypass grafting. However, the indication of most interest to the public and physicians is evaluating patients for native vessel coronary artery disease (CAD) using coronary artery calcium (CAC) scoring and coronary computed tomographic angiography (CTA).We searched the PubMed database and Google, from inception to September 2009, for keywords coronary artery calcium, coronary CT angiography, and radiation risk to identify information sources of interest. We also searched references in other review articles. From Google, we selected publications from trusted sources, such as the Food and Drug Administration and the National Academy of Sciences. From PubMed, we selected articles about test performance characteristics based on the quality of their methods, preferentially using randomized controlled trial data. We selected articles about clinical outcomes from randomized trials when available and from large cohorts as secondary sources. The purpose of this review is to summarize the recent data regarding accuracy, sensitivity, and specificity of CTA and the responsible use of cardiac CT.     

Assessment of the presence and extent of coronary collateralization by coronary computed tomographic angiography in patients with total occlusions

Coronary computed tomography angiography (CTA) may be helpful to manage patients with chronic coronary occlusions. The aim of this study was to determine the sensitivity and specificity of CTA to detect the presence and extent of coronary collaterals as compared to invasive coronary angiography (ICA). We retrospectively evaluated 26 patients who underwent both coronary CTA and ICA within 3 weeks and demonstrated a total coronary occlusion (TIMI grade 0) in one of the major coronary arteries. CTA was performed using a 64-slice multidetector CT. The presence, and extent of collateralization was assessed by two blinded observers using the Rentrop classification for ICA. CTA accurately identified the presence and location of all 26 total occlusions. The presence of any collaterals was accurately detected in 21/23 patients [sensitivity 91% (CI: 71–98%)] and the absence in three patients [specificity 100% (CI: 29%–100%)]. The sensitivity of coronary CTA to identify patients with collateralization increased from 91 to 94% (CI: 71–99%) and 100% (CI: 59–100%) for collaterals Rentrop grade 2 and 3 in ICA, respectively. Coronary CTA accurately detects the presence of any coronary collateralization in patients with total occlusions. Although CT technology is currently limited in the assessment of individual collaterals and smaller vessels, it may be helpful in the management of patients with total occlusions.     

Influence of coronary calcification on the diagnostic accuracy of 64-slice computed tomography coronary angiography: a systematic review and meta-analysis

To determine via meta-analysis the diagnostic accuracy of 64-slice computed tomography coronary angiography (CTA) for assessment of significant obstructive coronary artery stenosis at different coronary artery calcium score (CACS) levels. Data of 12,053 versus 5,890 segments, 906 versus 758 arteries and 1,120 versus 514 patients in low versus high CACS subgroups from 19 eligible studies were compared. The per-patient prevalence of coronary artery disease was 48% versus 68%, respectively. Subgroups were stratified by different CACS thresholds ranging from 100 to 400. Meta-analyses of per-patient data comparing overall low versus high CACS subgroups resulted in a sensitivity of 97.5 (95.5–99)% versus 97 (94.5–98.5)%, specificity of 85 (82–88)% versus 66.5 (58–74.5)%, diagnostic odds ratio of 153 (81–290) versus 40 (20–83), positive predictive value of 85 (82–87)% versus 86 (84–88)%, negative predictive value of 97.5 (95–99)% versus 91 (88–94)% and overall accuracy of 91% versus 89% with 95% confidence interval, respectively. The drop in specificity was significant (P = 0.035), while the sensitivity and overall accuracy were insignificantly changed (P > 0.05). Meta-analyses of independent subgroups at CACS levels ≤10 and ≤100 demonstrated high specificities of 90 (94–100)% and 88.5 (81–91.5)%, whereas at CACS levels ≥400 the specificity declined significantly to 42 (28–56)% but with consistently retained high sensitivity of 97.5 (94–99)%. The specificity of CTA decreases with increasing CACS, while the sensitivity remains high independent of that. The suggested CACS thresholds are arbitrary and do not necessarily warrant cancelling angiography. Diagnostic studies are needed to explore whether a specific CACS threshold may serve as a pre-angiographic gatekeeper to prevent likely equivocal angiographies.