Interpreting the evidence: How accurate is coronary computed tomography angiography?

Coronary CT angiography (CTA) has evolved rapidly into a powerful diagnostic tool. More than 30 accuracy studies have reported accuracy results in >2000 patients. A meta-analysis of 29 studies found per-patient accuracy of 96% sensitivity, 74% specificity, 83% positive predictive value, and 94% negative predictive value. Several clinical studies support the safety and accuracy of coronary CTA for acute chest pain, after inconclusive stress testing, and in preoperative evaluation of patients before cardiac valve surgery. Accuracy studies suffer from selection bias because of the inclusion only of patients previously selected to undergo invasive angiography. This increases the incidence of true disease, raising apparent sensitivity and lowering negative predictive value, although the latter remains high at 94%. CTA has relatively low accuracy for the quantitative assessment of stenosis severity. CTA accuracy studies show high figures for sensitivity and negative predictive value in detection of coronary lesions. CTA less accurately shows lesion severity, and intermediate-grade lesions require physiologic evaluation. Clinical studies support the effectiveness of CTA for exclusion of significant coronary disease.     

Coronary artery bypass graft imaging using ECG-gated multislice computed tomography: comparison with catheter angiography

AIM: To compare the value of multislice computerized tomography (MSCT) in imaging coronary artery bypass grafts (CABGs) by direct quantitative comparison with standard invasive angiography. METHODS: Using MSCT, 50 consecutive patients who had previously undergone CABG surgery and had recently undergone invasive angiography for recurrent angina pectoris, were studied further using MSCT after intravenous injection of non-ionic contrast agent; cardiac imaging was performed during a single breath-hold. Graft anatomy was quantified, using both quantitative coronary angiography (QCA) and MSCT, by different investigators blinded to each other. Reproducibility was quantified using the standard error of the measurement expressed as a percentage in log-transformed values (CV%) and intraclass correlation (ICC). RESULTS: All 150 grafts were imaged using MSCT; only 4 patent grafts were not imaged using selective angiography. Good agreement was achieved between MSCT and QCA on assessment of proximal anastomoses (CV% 25.2, ICC 0.84), mid-vessel luminal diameter (CV% 15.5, ICC 0.91) and aneurysmal dilations (CV% 14.3). Reasonable agreement was reached on assessment of distal anastomoses (CV% 26.7, ICC 0.66) and categorization of distal run-off (ICC 0.73). Good agreement was observed for stenoses of over 50% luminal loss (CV% 8.7, ICC 0.97) but agreement on assessment of less severe lesions was poor (CV% 208.7, ICC 0.51). CONCLUSION: This study demonstrates that CABGs can be quantitatively evaluated using MSCT, and that significant lesions present in all CABG segments can be reliably identified. Agreement between MSCT and QCA for lesions of less than 50% luminal loss was poor.     

前置体型特异性剂量估算值优化CT冠状动脉成像的可行性

目的 探讨前置体型特异性剂量估算值（SSDE）优化CT冠状动脉成像（CCTA）的可行性。方法 回顾性分析2018年3月至2018年5月衢州市人民医院90例行CCTA扫描的患者资料,建立水等效直径（d_w）与体质量指数（BMI）的回归方程,并计算容积CT剂量指数（CTDI_vol）上四分位数。前瞻性收集2018年12月至2019年1月衢州市人民医院行CCTA扫描患者67例,按随机数表法分为对照组（32例）和试验组（35例）。对照组使用固定CTDI_vol设定扫描方案,试验组使用固定SSDE设定扫描方案。两组的目标剂量为90例患者CTDI_vol的上四分位数。评估并比较两组图像质量及辐射剂量。结果 90例患者BMI与d_w正相关（r=0.823,P<0.05）,回归方程为d_w=9.241+0.644×BMI;CTDI_vol的上四分位数为7.92 mGy。对照组和试验组冠状动脉血管段图像质量的优良率分别为94.10%（367/390）和93.93%（402/428）,差异无统计学意义（P> 0.05）;对照组和试验组SNR和CNR的中位数分别为21.08、24.39和17.24、19.94,差异无统计学意义（P> 0.05）。试验组的CTDI_vol、SSDE和女性乳腺辐射剂量（D_bre）分别较对照组降低37.04%、35.77%和37.37%,差异均具有统计学意义（z=-7.041,t=18.479,15.079,P<0.05）。结论 基于前置SSDE设定CCTA方案具有可行性,保证图像质量的同时,可有效降低辐射剂量。     

128层CT冠状动脉成像对左心室功能的评价

目的:应用冠状动脉成像原始数据,了解左心室形态变化,评价整体左心室功能。方法:收集90例患者冠状动脉成像原始数据,行MPR,观察左心室形态和各心肌节段的变化,并应用心功能分析软件自动计算出左心室收缩末期容积(ESV)、舒张末期容积(EDV)和射血分数(EF)。根据冠状动脉、左心室形态及整体左心室功能,将所有患者分为对照组、冠心病组、左心室肥厚组及心功能衰竭组,结合各组左心室形态变化,将左心室ESV、EDV和EF进行统计学比较和分析。结果:对照组患者冠状动脉和左心室形态正常;冠心病组左心室壁局限性增厚7例和变薄13例;左心室肥厚组左心室缩小、心室壁增厚;心功能衰竭组心室扩大、室壁普遍变薄。对照组、冠心病组、左心室肥厚组、心功能衰竭组平均EDV和ESV分别为(133.58±14.91)mL、(51.33±11.06)mL;(130.68±11.53)mL、(56.16±8.24)mL;(97.59±8.18)mL、(29.53±4.78)mL;(229.40±50.64)mL、(171.27±60.64)mL。冠心病组与对照组平均EDV和ESV比较,差异无统计学意义,左心室肥厚组及心功能衰竭组与对照组比较,差异均有统计学意义(P0.001)。对照组、冠心病组、左心室肥厚组、心功能衰竭组EF分别为(61.25±5.83)%、(56.37±6.79)%、(68.94±5.36)%和(26.33±8.30)%,差异均有统计学意义。结论:应用冠状动脉成像原始数据,结合冠状动脉及左心室形态改变,无创评价左心室整体功能,实用而可行,可为临床提供更多有价值的信息。     

Dual source computed tomography coronary angiography in new onset cardiomyopathy

AIM:To evaluate safety and utility of coronary computed tomography angiography(CCTA) compared to invasive coronary angiography(ICA) in new cardiomyopathy.METHODS:Eighteen patients(mean age 56.5 years,10 males) who presented for evaluation of new onset heart failure with evidence of systolic dysfunction(ejection fraction < 40%) on echocardiography and recent ICA were prospectively enrolled.Patients with known coronary artery disease,atrial fibrillation,creatinine > 1.5 g/dL,and contraindication to intravenous contrast administration were excluded.CCTA was performed using a dual source 64-slice scanner.Mean heart rate was 75 beats per minute.Stenosis was graded for each coronary segment as:none,mild(< 50%),moderate(50%-70%),severe(> 70%),or non-evaluable.Ischemic cardiomyopathy(ICM) was diagnosed if severe stenosis was present in the left main,proximal left anterior descending artery,or two or more major arteries.RESULTS:Two patients were diagnosed with ICM by ICA.CCTA correctly identified 2 patients with ICM and 16 patients as non-ICM.CCTA successfully evaluated 240/246 coronary segments with an accuracy of 97.5%,sensitivity 70%,specificity 98.7%,positive predictive value of 70%,and negative predictive value of 98.7% for identifying severe stenosis on a per-segment level.CONCLUSION:Dual source 64-slice multi-detector CCTA is a safe,accurate,and non-invasive technique for diagnosing ICM in patients presenting during the acute phase of newly diagnosed cardiomyopathy.     

Effect of a calcium deblooming algorithm on accuracy of coronary computed tomography angiography

BackgroundCoronary artery calcification is a significant contributor to reduced accuracy of coronary computed tomographic angiography (CTA) in the assessment of coronary artery disease severity. The aim of the current study is to assess the impact of a prototype calcium deblooming algorithm on the diagnostic accuracy of CTA.Methods40 patients referred for invasive catheter angiography underwent CTA and invasive catheter angiography. The CTA were reconstructed using a standard soft tissue kernel (CTA_STAND) and a deblooming algorithm (CTA_DEBLOOM). CTA studies were read with and without the deblooming algorithm blinded to the invasive coronary angiogram findings. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value for the detection of stenosis ≥50% or ≥70% were evaluated using quantitative coronary angiography as the reference standard. Image quality was assessed using a 5-point scale, and the presence of image artifact recorded.ResultsAll studies were diagnostic with 548 segments available for evaluation. Image score was 3.64 ± 0.72 with CTA_DEBLOOM, versus 3.56 ± 0.72 with CTA_STAND (p = 0.38). CTA_DEBLOOM had significantly less calcium blooming artifact than CTA_STAND (12.5% vs. 47.5%, p = 0.001). Based on a 50% stenosis threshold for defining significant disease, the Sensitivity/Specificity/PPV/NPV/Accuracy were 65.9/84.9/27.6/96.6/83.4 for CTA_DEBLOOM and 75.0/81.9/26.6/97.4/81.4 for CTA_STAND using a ≥50% threshold. CTA_DEBLOOM specificity was significantly higher than CTA_STAND (84.9% vs. 81.5%, p = 0.03), with no difference between the algorithms in sensitivity (p = 0.22), or accuracy (p = 0.15). These results remained unchanged when a stenosis threshold of ≥70% was used. Interobserver agreement was fair with both techniques (CTA_DEBLOOM k = 0.38, CTA_STAND k = 0.37).ConclusionIn this proof of concept study, coronary calcification deblooming using a prototype post-processing algorithm is feasible and reduces calcium blooming with an improvement of the specificity of the CTA exam.     

冠状动脉CT血管成像和运动平板试验对冠心病患者的诊断比较

目的:评价冠状动脉CT血管成像(CCTA)和运动平板试验(TET)对冠心病的诊断价值。方法:以常规冠状动脉造影(CAG)为诊断冠心病(冠脉狭窄≥50%)的"金标准",对同期先后行TET、CCTA和CAG 3种检查的75例疑似冠心病患者进行回顾性分析,将其TET和CCTA的结果与CAG进行比较。结果:TET和CCTA诊断冠心病的敏感度分别为45.2%和90.5%,特异度为69.7%和93.9%,阳性预测值为65.5%和95.0%,阴性预测值为50.0%和88.6%,准确率为56.0%和92.0%,P<0.01。在冠状动脉血管水平CCTA对右冠状动脉、左主干、前降支、回旋支狭窄诊断的准确率分别为86.7%、100.0%、88.0%和76.0%。冠心病患者中TET诊断阳性率与病变血管支数呈正相关(r=0.440,P=0.004);冠心病患者TET诊断结果阳性与阴性仅与血管狭窄程度≥75%狭窄的节段数目有统计学差异(P=0.016)。结论:CCTA诊断冠心病较TET有更高的诊断准确性和较低的诊断假阳性和假阴性,对有症状的疑诊冠心病患者CCTA的诊断具有更重要作用。     

Coronary manifestations of Kawasaki Disease in computed tomography coronary angiography

Coronary arteritis in Kawasaki disease can lead to serious complications such myocardial infarction and sudden death. The identification of coronary manifestations with a method that is minimally invasive and of low radiation exposure is therefore important in paediatric patients with Kawasaki disease. Coronary CT angiography can be an attractive alternative to invasive coronary angiography. This paper describes imaging techniques for coronary CT angiography in pediatric patients and demonstrates the spectrum of cardiovascular manifestations in patients with Kawasaki disease.     

FFR CT诊断冠心病的初步应用体会

目的初步探究基于CT血管成像的无创血流储备分数（FFR_CT）与传统有创血流储备分数（FFR）相比在冠心病病人心肌缺血诊断方面的应用价值。方法纳入2017年2月-12月于我院接受冠状动脉CT血管成像（CCTA）检查且后续1周内完成冠状动脉造影（ICA）及FFR检查的可疑或确诊冠心病的病人20例,其中男13例,女7例,平均年龄（64.72±8.01）岁。对病人CCTA影像采用简化一维cFFR软件进行FFR_CT值测定,以有创性FFR结果作为金标准,分析比较FFR_CT对冠心病病人心肌缺血诊断的敏感度、特异度、阳性预测值、阴性预测值、准确度。绘制受试者操作特征（ROC）曲线,比较FFR_CT与CCTA的诊断准确性。采用Pearson相关性检验及Bland-Altman方法比较FFR_CT与FFR的诊断相关性及一致性。结果以病变为分析单位,FFR_CT与CCTA诊断敏感度、特异度、阳性预测值、阴性预测值、准确度分别为93.5%、86.2%、87.9%、92.6%、90.0%及83.9%、79.3%、82.1%、81.2%、81.7%。FFR_CT和CCTA的ROC曲线下面积分别为0.960及0.892。FFR_CT与FFR诊断一致性及相关性良好（r=0.973,P<0.001）。结论FFR_CT对于冠心病病人心肌缺血诊断具有良好的临床应用价值。     

多层螺旋CT无创性冠状动脉造影图像质量分析及冠状动脉病变评价

目的分析多层螺旋CT无创性冠状动脉造影图像质量的主要影响因素,以正确评价冠状动脉病变。方法64例患者行多层螺旋CT冠状动脉造影检查,用回顾性心电门控选择最佳相位窗,并分别以容积再现（VR）、最大密度投影（MIP）、曲面重建（CPR）等后处理技术将冠状动脉分为15个节段进行分析。结果显示血管直径大于2mm的冠状动脉节段共960个,能满足影像学评价的节段共884个（92．08％）;不能满足影像学评价的节段共76个（7．92％）;64例中的58例（90．63％）冠状动脉CTA图像质量均为2级或1级,其余6例（9．37％）冠状动脉CTA图像质量为3级,共发现冠状动脉存在中、重度狭窄者44例（占68．75％）,其中单支病变28例,双支病变16例;另发现冠状动脉存在轻度狭窄者16例（占25．00％）,其中单支病变8例,双支病变8例;冠状动脉未见明确狭窄者4例（6．25％）。结论高质量的MSCT无创性冠状动脉造影对冠状动脉病变有较高的诊断价值。     

动态容积320排冠状动脉CT血管成像诊断冠状动脉疾病的意义

目的：研究320排动态容积冠状动脉CT成像（CCTA）诊断冠状动脉疾病（CAD）的可行性。方法：5961例临床诊断CAD的患者进行CCTA检查,其中186例接受常规X线冠状动脉造影术（CAG）,对照分析其检查结果。1490例接受CCTA检查的健康查体者作为对照。结果：成像质量均在I～III级,无呼吸伪影图像。在186例CAD患者中,CCTA诊断冠状动脉狭窄（狭窄度≥50％）的敏感性为96．72％,特异性98．95％,阳性预测值95．16％,阴性预测值99．30％,准确度98．56％。结论：320排动态容积CT冠状动脉成像图像清晰,对诊断CAD具有重要的临床价值。     

64层螺旋CT冠状动脉成像临床应用评价

目的:评价64层螺旋CT冠状动脉成像(64SCTCA)的图像质量和在诊断冠状动脉疾病的临床价值。方法:搜集35例患者64SCTCA的完整资料,并以近期实施的选择性X线冠状动脉成像(SCA)结果为金标准进行对比,对64SCTCA显示的冠状动脉主支及主要分支情况进行分级评估。结果:35例病例可用于评估的冠状动脉共计368支,成功率达95.6%。其中SCA共显示74个节段冠脉有中、重度狭窄(≥50%)。MSCTCA诊断中重度狭窄的敏感性为86.5%,特异性为97.3%,阳性预测值88.9%,阴性预测值96.6%。经配对χ2检验,P>0.05,证明两种检查方法在发现冠状动脉病变方面差异无统计学意义。结论:64层螺旋CT冠状动脉成像是一种无创、快速的成像方法,对诊断冠状动脉≥50%狭窄有较高的敏感性和特异性,适合用于临床怀疑冠心病的患者SCA前的筛选检查。     

1879例成人非先天性心脏病患者双源CT检出的冠状动脉起源异常24例分析

目的：评价双源CT（DSCT）在成人非先天性心脏病患者冠状动脉起源异常检出中的价值。方法：回顾性分析2008年9月,2009年2月期间进行了DSCF冠状动脉检查的资料,总结成人非先天性心脏病患者冠状动脉起源异常的检出率。结果：1881例进行冠状动脉检查的患者中,共有1879例患者为非先天性心脏病患者,共检出了24例冠状动脉起源异常,检出率为1．3％。其中15例为右冠状动脉起源异常（12例起自左冠状窦,3例为高位起源）,8例为左冠状动脉起源异常（3例起自无冠状窦,回旋支起自左冠状窦、高位开口、回旋支起自右冠状动脉、左冠状动脉起自右冠状窦、单一冠状动脉各1例）,1例为左右冠状动脉均起源异常（均为高位开口）。结论：本组成人非先天性心脏病患者冠状动脉起源异常的检出率为1．3％。DSCT可很好地显示冠状动脉起源异常和走行,为临床决策提供重要信息。     

Assessment of coronary artery stent patency and restenosis using 64-slice computed tomography

RATIONALE AND OBJECTIVES: Restenosis remains a major limitation of coronary catheter-based stent placement. Therefore, a reliable noninvasive diagnostic method for the evaluation of stented coronary arteries would be highly desirable. Our aim was to evaluate the diagnostic accuracy of high-resolution 64-slice computed tomography (64SCT) in a pilot study for the assessment of the lumen of coronary artery stents. MATERIALS AND METHODS: Twenty-five patients underwent 64SCT of the coronary arteries and quantitative x-ray coronary angiography (QCA) after coronary artery stent placement. 64SCT coronary angiography was performed with the following parameters: spatial resolution = 0.4 x 0.4 x 0.4 mm; temporal resolution = 83-165 milliseconds; contrast agent = 80 mL at a flow rate of 5 mL/second; retrospective electrocardiogram gating. The 64SCT scans were evaluated for image quality and for the presence of significant in-stent and peri-stent (proximal and distal) stenoses. Determinations were made of the sensitivity, specificity, diagnostic accuracy, and positive and negative predictive values (PPV and NPV) of 64SCT for the detection or exclusion of stenoses. RESULTS: A total of 46 stents were evaluated, of which 45 (98%) were of diagnostic image quality. Significant in-stent restenosis or occlusion was detected on QCA in 8/45 cases (>/=50% stenosis = 6; occlusion = 2). The sensitivity, specificity, accuracy, PPV, and NPV of 64SCT for the detection of significant in-stent disease was 75%, 92%, 89%, 67%, and 94%, respectively. Both occluded coronary artery stents were correctly identified. The sensitivity, specificity, and accuracy values of 64SCT for the detection of significant proximal peri-stent stenoses were 75%, 95%, and 93%, respectively, whereas the values for detection of significant distal peri-stent stenoses were 67%, 85%, and 84%, respectively. CONCLUSION: The high spatial and temporal resolution of 64SCT may permit improved assessment of stent occlusion and peri-stent disease, although detection of in-stent stenosis remains difficult.     

Role of 320-slice multislice computed tomography coronary angiography in the assessment of coronary artery stenosis

Objective

To evaluate the effectiveness of the multislice CT coronary angiography, as a non-invasive imaging tool in assessment of coronary artery stenosis.

Patients and methods

The study included 50 patients who were referred for MSCT coronary angiography followed by catheter coronary angiography. Patients with previous coronary bypass grafts and those with coronary stents were excluded. History of contrast allergy, renal impairment and severe chest conditions were exclusion criteria. The coronary angiographic CT studies were performed using a 320 CT scanner. The catheter coronary angiographic studies were performed via femoral arterial puncture. The results of CT angiography were compared with the gold standard catheter angiography.

Results

The positive predictive value and negative predictive value of MSCT coronary angiography in detection of coronary artery stenosis were 94% and 100%, respectively.

Conclusion

In conclusion, MSCT coronary angiography is a very helpful and rapid non-invasive coronary imaging modality that was able to detect and grade coronary artery stenosis better than other noninvasive examinations used to detect CAD, such as exercise stress testing. Due to its very high negative predictive value, it may eliminate the need for invasive coronary procedures in the presence of normal coronary imaging.     

Accuracy of coronary computed tomography angiography vs intravascular ultrasound for evaluation of vessel area

BackgroundWe evaluated the accuracy of commonly used thresholds for vessel area evaluation on coronary CT angiography (CTA) and assessed ability of CTA to image the adventitial border.MethodsWe evaluated 137 paired (coronary CTA and intravascular ultrasound [IVUS]) coronary artery cross-sections in 30 patients. CTA analysis included measurements of external vessel border area defined at Hounsfield unit (HU) thresholds of 0 (presumed adventitia), 50, and 70 (presumed external elastic membrane [EEM]). IVUS analysis included measurements of lumen, EEM, and outer border of the highly echogenic area adjacent to EEM (presumed adventitia area).ResultsHigh correlation was found between CTA and IVUS measurements for EEM areas (R² = 0.65, P < .001 and R² = 0.60, P < .001 for CTA thresholds of 50 and 70 HU, respectively). CTA and IVUS measurements of adventitia areas were significantly correlated (R² = 0.74; P < .001), with no significant difference between the 2 methods (20.2 ± 6.4 mm² vs 19.8 ± 6.4 mm², respectively; P = .278). Cross-sectional coronary lumen radiodensity on CTA images and plaque burden measured on IVUS significantly affected the accuracy of CTA in assessment of the EEM area but not the presumed adventitial area.ConclusionsWe have demonstrated that use of a 50-HU threshold for vessel area determination by CTA led to its significant overestimation, whereas 70-HU threshold was close to that of EEM on IVUS. CTA may accurately delineate the coronary adventitial border by using a 0-HU threshold.     

评价迭代重建法与滤过反投影法在冠状动脉CTA检查中的价值

目的：对行冠状动脉CTA检查的患者原始数据应用低剂量自适应迭代重建技术（AIDR ）与滤过反投影法（FBP ）两种方法的图像进行比较,旨在了解迭代重建算法的图像质量及其临床应用价值。方法：26例临床疑似稳定性心绞痛患者采用320排CT行冠状动脉CTA检查。利用AIDR 重建的常规X线剂量方案扫描,对采集得到的原始数据分别用AIDR和FBP两种方法进行图像重建。测量升主动脉开口、右冠状动脉近段、左冠状动脉主干、右冠状动脉中段、左前降支近段及左回旋支近段的CT值、背景SD并计算分析SNR、CNR值。比较两者的图像质量。结果：26例患者都在一次心动周期完成冠状动脉检查。在血管各节段测得的平均CT值差异无统计学意义（P＞0．05）,背景SD值的差异有统计学意义（P＜0．001）,计算得到的SNR、CNR差异有统计学意义（P＜0．001）。两组图像质量的主观评分差异有统计学意义,AIDR （3．73±0．49）、FBP（3．59±0．61）（P＜0．01）。结论：应用AIDR重建法的图像质量优于FBP 重建法,迭代重建技术可明显降低图像噪声,改善影像质量并具有降低辐射剂量的作用。     

Influence of intracoronary attenuation on coronary plaque measurements using multislice computed tomography: observations in an ex vivo model of coronary computed tomography angiography

Assessment of attenuation (measured in Hounsfield units, HU) of human coronary plaques was performed using multislice computed tomography (MSCT) in an ex vivo model. In three ex vivo specimens of left coronary arteries in oil, MSCT was performed after intracoronary injection of four solutions of contrast material (400 mgI/ml iomeprol). The four solutions were diluted as follows: 1/, 1/200, 1/80, and 1/20. All scans were performed with the following parameters: slices/collimation 16/0.75 mm, rotation time 375 ms. Each specimen was scored for the presence of atherosclerotic plaques. In each plaque the attenuation was measured in four regions of interest for lumen, plaque (non-calcified thickening of the vessel wall), calcium, and surrounding (oil surrounding the vessel). The results were compared with a one-way analysis of variance test and were correlated with Pearsons test. There were no significant differences in the attenuation of calcium and oil in the four solutions. The mean attenuation in the four solutions for lumen (35±10, 91±7, 246±18, 511±89 HU) and plaque (22±22, 50±26, 107±36, 152±67 HU) was significantly different between each decreasing dilution (p<0.001). The mean attenuation of lumen and plaque of coronary plaques showed high correlation, while the values were significantly different (r=0.73; p<0.001). Intracoronary attenuation modifies significantly the attenuation of plaques assessed with MSCT.