Coronary calcium score as gatekeeper for 64-slice computed tomography coronary angiography in patients with chest pain: per-segment and per-patient analysis

We sought to investigate the performance of 64-slice CT in symptomatic patients with different coronary calcium scores. Two hundred patients undergoing 64-slice CT coronary angiography for suspected coronary artery disease were enrolled into five groups based on Agatston calcium score using the Mayo Clinic risk stratification: group 1: score 0, group 2: score 1–10, group 3: score 11–100, group 4: score 101–400, and group 5: score > 401. Diagnostic accuracy for the detection of significant (≥50% lumen reduction) coronary artery stenosis was assessed on a per-segment and per-patient base using quantitative coronary angiography as the gold standard. For groups 1 through 5, sensitivity was 97, 96, 91, 90, 92%, and specificity was 99, 98, 96, 88, 90%, respectively, on a per-segment basis. On a per-patient basis, the best diagnostic performance was obtained in group 1 (sensitivity 100% and specificity 100%) and group 5 (sensitivity 95% and specificity 100%). Progressively higher coronary calcium levels affect diagnostic accuracy of CT coronary angiography, decreasing sensitivity and specificity on a per-segment base. On a per-patient base, the best results in terms of diagnostic accuracy were obtained in the populations with very low and very high cardiovascular risk. Authors have no financial conflict of interest. Neither this paper nor any of its content has not been submitted to other journals.     

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.     

16层螺旋CT冠状动脉成像的技术与应用

目的:探讨多层螺旋CT冠状动脉造影(multislice spiral CT coromary angiography,MSCTCA)的成像技术和临床应用价值。方法:37例患者行MSCTCA检查,利用多种方法进行重建,分析影响冠状动脉图像质量的重要因素,MSCTCA对冠状动脉的显示能力,冠状动脉狭窄程度的评价,冠状动脉斑块性质的判断,冠状动脉的解剖变异,并了解桥血管和支架的通畅性。结果:容积再现图像最佳的显示相位窗为75%,左主干、左前降支重建的最佳相位为75%,右冠和左回旋支为50%~70%。MSCTCA能显示的管腔最小径1.5mm。对冠状动脉的解剖变异、冠状动脉狭窄的程度、斑块的性质及桥血管和内支架显示良好。结论:MSCTCA可作为冠心病介入治疗前的筛选,能能评价斑块的性质,在血运重建后的复查中也有很高的应用价值,并能提供冠状动脉其他病变的信息。     

16层螺旋CT冠状动脉成像的临床应用

目的:探讨16层螺旋CT冠状动脉(简称冠脉)成像在冠心病诊断中的临床价值。方法:选取50例临床诊断或可疑冠心病患者行16层螺旋CT冠状动脉造影检查(MSCTCA),先行冠脉钙化积分平扫,然后行冠脉增强扫描,选取一组质量最佳的薄层图像行冠脉三维重建,分析MSCTCA对冠状动脉狭窄性病变的显示能力,并对冠脉支架显示及通畅性进行评价。结果:冠脉钙化积分与其狭窄程度呈正相关,中度以上狭窄的冠脉钙化积分值明显高于轻度狭窄,其间有统计学显著性差异(P<0.001)。MSCTCA对诊断有临床意义的冠脉中度以上狭窄的敏感度、特异度、诊断准确率、阳性预测值、阴性预测值分别约89.6%、93.9%、92.6%、86.7%、95.4%。MSCTCA对冠脉支架显示良好,检出5例9根支架,其中2根支架不通畅,出现支架内再狭窄。结论:16层螺旋CT冠脉成像安全、无创,对评价冠状动脉狭窄、支架开放及通畅性等方面有着较高的临床应用价值,可作为冠心病筛查的有效手段以及介入和手术治疗后的随访手段。     

Usefulness of multislice spiral computed tomography coronary angiography in patients with acute chest pain in the emergency department

Background

Despite reports that multislice spiral computed tomography (MSCT) has high sensitivity and specificity in preselected patient populations, the routine clinical feasibility and utility of MSCT coronary angiography in patients with acute chest pain in the emergency department remains uncertain.

Objectives

We sought to determine whether 16-slice MSCT coronary angiography can provide diagnostically useful images in patients with acute chest pain in the emergency department.

Methods

Ninety-eight patients in the emergency department (41 men, 57 women; mean age ± SD, 48.1 ± 11.9 y) with acute chest pain underwent MSCT coronary angiography. Coronary calcium (Agatston) scoring was performed, followed by contrast-enhanced MSCT. Images were evaluated for mean image quality (MIQ) and for degree of stenosis. These data were correlated with body mass index (BMI; in kg/m²), heart rate, beat-to-beat variation, and calcium score to assess their influence on image quality.

Results

The 28 patients (29%) with nondiagnostic MIQs had significantly higher BMIs (mean ± SD, 32.9 ± 9.1 vs 28.9 ± 6.7; P < 0.05) and heart rates (mean ± SD, 71.0 ± 11.9 beats/min vs 65.6 ± 9.9 beats/min; P < 0.05) than patients with diagnostic MIQs. Forty-five patients (46%) had at least 1 nondiagnostic coronary segment. These patients had significantly higher heart rates (mean ± SD, 70.5 ± 10.3 vs 64.1 ± 13.7; P < 0.05) than patients with only diagnostic-quality scans. Image quality correlated inversely and strongly with BMI and heart rate.

Conclusions

Sixteen-slice MSCT coronary angiography cannot routinely provide diagnostically useful images in patients with acute chest pain in the emergency department.     

前瞻性心电门控双源CT冠状动脉成像在高心率患者中应用的可行性研究

目的 探讨心率不低于91次/分(bpm)患者回顾性心电门控双源CT(DSCT)冠状动脉成像R-R间期的最佳重建时相,从扫描时相选择的角度分析前瞻性心电门控(简称前门控)应用的可行性.方法 分析232例行回顾性心电门控DSCT冠状动脉成像患者(体质量指数23～25 kg/m2,心率≥91 bpm)的图像,根据扫描过程中患者屏气时心电监控记录到的心率将其分为3组(A～C组),A组83例,心率91～95 bpm,B组68例,心率96～100 bpm,C组81例,心率≥101 bpm.每隔3%重建1个时相,分别由2名医师独立对横断面图像、薄层MIP、CPR、VRT图像质量采用5分法进行综合评估,按照15段分段法,选出每个节段的R-R间期的最佳重建时相及范围.采用Kappa检验,评价2名医师对冠状动脉图像评分的一致性.结果 232例患者中,可评价冠状动脉节段共3343个,其图像最佳重建时相范围集中在81%～61%和51%～31%.3组冠状动脉节段与之相对应的节段数百分比:A组(91～95 bpm,83例的1183个节段)分别为5.49%、94.51%;B组(96-100 bpm,68例986个节段)分别为0.20%、99.80%;C组(≥101 bpm,81例1174个节段)分别为0.17%、99.83%.232例患者的3343个冠状动脉节段中3274个节段(97.94%)最佳重建时相范围集中在以41%为中心的51%～31%R-R间期范围内.2名医师对232例患者的3343个冠状动脉节段图像质量的评分结果得到了较高的一致性(Kappa值=0.883,P<0.05).结论 具有稳定的窦性心律,且屏气时平均心率≥91 bpm患者,冠状动脉节段的最佳重建时相集中于以R-R间期41%为中心的51%～31%,从扫描时相选择的角度考虑,可以对稳定高心率(≥91 bpm)患者行前门控横断面扫描,并且预设41%为曝光时间窗,成功把握较大.     

64层螺旋CT在冠状动脉疾病诊断中的价值

目的 评价64层螺旋CT冠状动脉成像（64SCTCA）在诊断冠状动脉疾病的临床价值。方法 搜集100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（CCA）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 所有病例可用于评估的920支冠状动脉中，共显示病变370支，其中348支得到CCA证实；22支64SCTCA诊断狭窄而CCA显示正常，另外有10例CCA确诊存在的病变而在64SCTCA上未能显示，得出64SCTCA诊断冠状动脉病变的敏感性为97．2％，特异性为96．0％，阳性预测值为94．0％，阴性预测值为98．1％。经配对χ^2检验，P=0．052，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。在显示病变程度上，64SCTCA评估与CCA完全一致者311支，准确性86．8％。在64SCTCA结果中，共有59支病变在程度上的评价与CCA结果不符合。结论 64SCTCA在显示冠状动脉病变时，具有较高的敏感性和特异性，并且对于病变程度的评估也比较准确，适合用于临床怀疑冠心病的患者CCA前的筛选检查。     

Influence of convolution filtering on coronary plaque attenuation values: observations in an ex vivo model of multislice computed tomography coronary angiography

Attenuation variability (measured in Hounsfield Units, HU) of human coronary plaques using multislice computed tomography (MSCT) was evaluated in an ex vivo model with increasing convolution kernels. MSCT was performed in seven ex vivo left coronary arteries sunk into oil followingthe instillation of saline (1/∞) and a 1/50 solution of contrast material (400 mgI/ml iomeprol). Scan parameters were: slices/collimation, 16/0.75 mm; rotation time, 375 ms. Four convolution kernels were used: b30f-smooth, b36f-medium smooth, b46f-medium and b60f-sharp. An experienced radiologist scored for the presence of plaques and measured the attenuation in lumen, calcified and noncalcified plaques and the surrounding oil. The results were compared by the ANOVA test and correlated with Pearson’s test. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The mean attenuation values were significantly different between the four filters (p < 0.0001) in each structure with both solutions. After clustering for the filter, all of the noncalcified plaque values (20.8 ± 39.1, 14.2 ± 35.8, 14.0 ± 32.0, 3.2 ± 32.4 HU with saline; 74.7 ± 66.6, 68.2 ± 63.3, 66.3 ± 66.5, 48.5 ± 60.0 HU in contrast solution) were significantly different, with the exception of the pair b36f–b46f, for which a moderate-high correlation was generally found. Improved SNRs and CNRs were achieved by b30f and b46f. The use of different convolution filters significantly modifief the attenuation values, while sharper filtering increased the calcified plaque attenuation and reduced the noncalcified plaque attenuation.     

Prevalence of myocardial bridging detected with 64-slice multidetector coronary computed tomography angiography in asymptomatic adults

Objective

Myocardial bridging is a congenital condition in which a segment of an epicardial artery has an intramural course within the myocardium. The aim of the present study was to evaluate the prevalence of myocardial bridging and the ability of 64-slice coronary computed tomography angiography to identify myocardial bridging in asymptomatic adults.

Methods

One hundred sixty-nine consecutive asymptomatic subjects underwent 64-row multidetector computed tomography (MDCT) of the coronary arteries. Two experienced CT radiologists identified myocardial bridging >1 mm in thickness, by consensus. We examined the frequency of myocardial bridging and evaluated the length, thickness, and coronary wall lesions.

Results

Myocardial bridges were found in 28 (17%) of 165 subjects. Twenty-one subjects (75%) had 1 bridge and 7 subjects (25%) had 2, for a total of 35 myocardial bridges. Twenty-one bridges (60%) were located in the left anterior descending, 8.5% in the diagonal branch, and 2.8% in the circumflex arteries. The segment beneath the myocardial bridge was always free of coronary wall plaques, but the arterial segment proximal to it had significant coronary wall plaques in 24 cases (68.6%).

Conclusion

We found that the incidence of myocardial bridging in asymptomatic adults is 7%, which is in agreement with some pathologic studies in the literature. Our study shows that MDCT of the coronary arteries is a reliable and noninvasive technique, which can accurately locate the site of myocardial bridging, and measure its thickness, course, and length.     

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.     

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。     

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。     

16层螺旋CT冠状动脉成像:毫秒相位重建法的应用

目的:探讨毫秒相位重建法在16层螺旋CT冠状动脉成像中的应用价值。方法:对18例利用常规百分比相位重建法重建冠状动脉CT图像失败或不理想的患者,使用毫秒级重建方法进行成像,探讨毫秒相位重建法应用的价值。结果:在显示冠状动脉血管节段总数上和能够达到诊断要求的血管节段的显示率方面,毫秒相位重建的方法均明显优于百分比相位重建,两者具有统计学意义(P<0.05)。结论:毫秒重建法可用于常规百分比相位选择法重建效果达不到诊断要求情况下的一种很有效的辅助措施。     

加注生理盐水对16层螺旋CT冠状动脉成像作用的探讨

目的:探讨加注生理盐水对16层螺旋CT冠状动脉成像的作用。方法:60例患者被随机分成两组,1组:注入对比剂欧乃派克120ml;2组:注入对比剂欧乃派克100ml及生理盐水40ml。所有患者均行16层螺旋CT冠状动脉增强扫描,分别测量左、右冠状动脉开口层面升主动脉、肺动脉及上腔静脉的CT值,测量左冠状动脉主干、左前降支、左回旋支及右冠状动脉的CT值,并用统计学软件SPSS分析。结果:升主动脉CT值1组显著低于2组,上腔静脉CT值1组显著高于2组。肺动脉CT值在左、右冠状动脉开口层面1组均高于2组,但差异在右冠状动脉开口层面有显著性意义,在左冠状动脉开口层面无显著性意义。各支冠状动脉CT值1组均显著低于2组。结论:加注生理盐水可以节省对比剂,降低上腔静脉及右心的密度,增加升主动脉的密度,便于更好地显示冠状动脉。     

Efficacy of pre-scan beta-blockade and impact of heart rate on image quality in patients undergoing coronary multidetector computed tomography angiography

OBJECTIVE: While beta-blockers are routinely administered to patients prior to coronary computed tomography angiography (CTA), their effectiveness is unknown. We therefore assessed the efficacy of beta-blockade with regards to heart rate (HR) control and image quality in an unselected patient cohort. METHODS: We studied 150 consecutive patients (104 men/46 female; mean age, 56+/-13 years) referred for coronary CTA. Intravenous metoprolol (5-20mg) was administered to patients with a HR >65 beats per minute (bpm). The goal HR was defined as an average HR <65 bpm without a single measurement above 68 bpm. RESULTS: Overall, 45% (68/150) of patients met the HR criteria for beta-blocker administration of which 76% (52/68) received metoprolol (mean dose 12+/-10mg). Of the 52 patients who received beta-blocker versus the 98 who did not, 18 (35%) versus 62 (64%) patients achieved the goal HR, respectively. All patients who achieved the target HR had an evaluable CTA while five patients who did not achieve the target HR had at least one non-evaluable coronary artery due to motion artifact. There was also a significant reduction in any motion artifact among those who achieved the goal HR as compared to those who did not (p=0.001). Logistic regression revealed an increase in the odds of stair step artifact of 11.6% (95% CI: 2.4% decrease, 27.5% increase) per 1 bpm increase in the standard deviation of scan HR. CONCLUSION: Overall, efficacy of beta-blocker administration to reach target HR is limited. Improvements in CT scanner temporal resolution are mandatory to achieve consistently high image quality independent of HR and beta-blocker administration.     

Radiation dose estimates in dual-source computed tomography coronary angiography

The purpose of this study was to quantify radiation dose parameters of dual-source CT coronary angiography. Eighty patients underwent contrast-enhanced, retrospectively ECG-gated dual-source CT coronary angiography with heart rate-adapted ECG pulsing using two algorithms: In 40 patients, the tube current was reduced to 20% (A_min1) of the normal tube current (A_max) outside the pulsing window; in 40 patients tube current was reduced to 4% (A_min2) of A_max. Mean CTDI_vol in the A_min1 group was 45.1 ± 3.6 mGy; the mean CTDI_vol in the A_min2 group was 39.1 ± 3.2 mGy, with CTDI_vol in the A_min2 group being significantly reduced when compared to the A_min1 group (P < 0.001). A significant negative correlation was found between CTDI_vol and heart rate in group A_min1 (r = −0.82, P < 0.001), whereas no correlation was found between CTDI_vol and heart rate in group A_min2 (r = −0.066). Using the conversion coefficient for the chest, dual-source CT coronary angiography resulted in an estimated mean effective dose of 8.8 mSv in the A_min1 group and 7.8 mSv in the A_min2. Radiation exposure of dual-source CT coronary angiography using an ECG-pulsing protocol reducing the tube current to 20% significantly decreases with increasing heart rates, despite using wider pulsing windows at higher heart rates. When using a protocol with reduced tube current of 4%, the radiation dose is significantly lower, irrespective of the heart rate.     

16排40层螺旋CT冠状动脉血管造影的应用技术探讨简

目的：探讨16排40层螺旋CT冠状动脉血管造影的应用技术。方法使用东芝公司16排螺旋CT进行冠状动脉血管成像检查,采用多平面重建（MPR）、最大密度投影（MIP）、曲面重建（CPR）和容积再现技术（VR）进行图像后处理,可清晰显示冠状动脉主干及主要分支。结果心率平稳为53~66次/min,冠状动脉节段图像质量可准确地显示冠状动脉通畅情况及管壁病变。心率＞68次/min时,冠状动脉的主要分支显示不规整。结论16排CT冠状动脉成像可比较准确诊断冠状动脉病变,具有较高的临床应用价值。     

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.     

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.