Coronary CT angiography with dual source computed tomography in 170 patients

Introduction

In preliminary studies DSCT provides robust image quality over a wide range of heart rates and excludes CAD with high accuracy.The aim of the present study was to evaluate the reproducibility of these results in a large, unselected and consecutive group of patients scheduled for invasive coronary angiography (ICA).

Material and methods

170 patients (124 men, 46 women; mean age: 64 ± 9 years) with known CAD (101 patients) or suspected CAD (69 patients) scheduled for ICA were examined by coronary CTA prior to ICA. All coronary segments were assessed for image quality (1: excellent; 5: non-diagnostic). The presence of significant vessel stenosis (>50%) was calculated using ICA as standard of reference.

Results

A total of 680 vessels were analyzed. Despite of 45 arrythmic patients all analyzed coronary segments were diagnostically evaluable. Mean Agatston score equivalent was 686 (range 0-4950). ICA revealed 364 lesions with ≥50% diameter stenosis. DSCT correctly identified 336 of these lesions. 115 lesions with a diameter stenosis ≤50% were overestimated by DSCT and thus considered as false-positive findings. On a per-segment basis, sensitivity was 92%, specificity 93%, positive predictive value (PPV) was 75% and negative predictive value (NPV) 98%. On a per-vessel basis DSCT revealed a sensitivity of 93%, a specificity of 88%, a PPV of 78% and a NPV of 97%. On a per-patient basis sensitivity was 94%, specificity 79%, PPV 88% and NPV 90%.

Conclusions

Initial results of preliminary studies showing robust image quality and high accuracy in DSCT cardiac imaging could be approved with the present study enclosing a large consecutive population. However severe coronary calcifications and irregular heart rate still remain limiting factors for coronary CTA.Despite improved image quality and high accuracy of coronary DSCT angiography, proof of indication is necessary, due to still remaining limiting factors.     

基于人工智能的冠状动脉CT血管成像检测阻塞性冠状动脉狭窄效能的研究

目的 以有创冠状动脉造影（ICA）为参考标准,探讨人工智能(AI)辅助的冠状动脉CT血管成像（CCTA）诊断阻塞性冠状动脉狭窄的效能。 方法 回顾性收集行CCTA检查并于3个月内行ICA检查的50例疑患冠状动脉疾病（CAD）的病人,男34例,女16例,平均年龄（61.8±8.5）岁。AI软件、不同年资医师（低/中/高年资）及AI+不同年资医师分别对入组病人CCTA影像进行后处理并解读。将ICA和CCTA上冠状动脉管腔狭窄≥50%定义为阻塞性冠状动脉狭窄。采用Agatston积分法测量病人的钙化积分值,并将病人分为低钙化组（钙化积分<100）和高钙化组（钙化积分≥100）。采用独立样本t检验对AI、医师及AI+医师的图像后处理和解读时间进行两两比较。以ICA为参考标准,分析AI在不同研究水平和高/低钙化组的诊断价值,并比较AI、不同年资医师和AI+不同年资医师的诊断敏感度、特异度、阳性预测值、阴性预测值、准确度及受试者操作特征（ROC）曲线下面积（AUC）。采用Pearson卡方检验或Fisher精确概率检验比较组间差异,采用DeLong检验比较AUC。 结果 50例病人共分析195支血管424个节段。AI和AI+医师的平均后处理和解读时间均低于单独医师诊断的时间（均P<0.05）,AI的时间较低/中/高年资医师分别减少了80%、76.8%和75%;AI+低/中/高年资医师较单独医师分别减少了67%、64%、57.9%。在病人、血管及节段水平,AI诊断阻塞性冠状动脉狭窄的敏感度分别为93.7%、83.1%、67.7%,特异度为50.0%、89.0%、91.0%,准确度为92%、86.7%、85.6%,阳性预测值为97.8%、83.1%、69.8%,阴性预测值为25%、89.0%、90.2%,AUC为0.87、0.89、0.83;在血管及节段水平,AI对低钙化组的特异度高于高钙化组（均P<0.05）。在血管水平,AI诊断的AUC值均低于中/高年资医师（均P<0.05）;其余研究水平,AI与其他不同年资医师诊断的AUC值差异均无统计学意义（均P>0.05）。3种研究水平下,AI+低/中/高年资医师诊断的AUC值与单独不同年资医师诊断的AUC值差异均无统计学意义（均P>0.05）。 结论 AI辅助的CCTA诊断阻塞性冠状动脉狭窄具有较好的诊断效能,且明显缩短后处理时间,可能成为临床医师诊断阻塞性冠状动脉狭窄的有效辅助工具。     

Detection of significant coronary artery stenosis with 64-section MDCT angiography

PURPOSE: To prospectively evaluate the diagnostic performance of 64-section multidetector computed tomography (MDCT) to detect significant coronary artery stenosis using conventional coronary angiography (CCA) as the reference standard. MATERIALS AND METHODS: Institutional Review Board approval and informed consent were obtained. In this prospective study, 80 patients (61 male, 19 female, mean age 56) were examined. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) were calculated. McNemar test was used to search for the significant difference between 64-section MDCT angiography and CCA to detect stenosis. Also, kappa index (kappa) for the agreement between MDCT angiography and CCA was calculated. RESULTS: The sensitivity, specificity, positive (PPV) and negative predictive values (NPV) for detecting significant stenosis were 96%, 98%, 91%, 99%, respectively. The sensitivity, specificity, PPV and NPV for classification of patients with or without CAD were 100% for all. McNemar test demonstrated no significant difference between 64-section MDCT angiography and CCA. Also, kappa index (kappa) indicated excellent agreement. CONCLUSION: Sixty-four section MDCT angiography is an effective diagnostic tool for the detection of significant coronary artery stenosis. Especially, the potential to differentiate patients with and without CAD may provide MDCT an important role in the prevention of unnecessary invasive diagnostic procedures.     

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。     

320排动态容积CT冠状动脉成像诊断冠心病的初步应用

目的探讨320排动态容积CT冠状动脉成像(CTA)诊断冠心病的准确性。方法 2010年3月至2010年9月对临床拟诊为冠心病的82例患者先后行冠状动脉CTA及冠状动脉造影(ICA)检查,并以ICA为金标准,评估320排CTA诊断冠状动脉狭窄≥50%及≥70%的敏感度、特异度、阳性预测值及阴性预测值。结果 CTA成像质量4分71例(86.6%),平均心率为67次/min;3分10例(12.2%),平均心率为74次/min;2分1例(1.2%),心率为83次/min;1分0例,全部病例均无阶梯伪影。CTA发现174个狭窄≥50%的节段,ICA发现144个以ICA为金标准,320排CTA诊断狭窄≥50%的敏感度、特异度、阳性预测值及阴性预测值分别为93.1%、96.0%、77.0%和99.0%。CTA发现40个狭窄≥70%的节段,ICA发现40个。以ICA为金标准,320排CTA诊断狭窄≥70%的敏感度、特异度、阳性预测值及阴性预测值分别为100%、95.6%、45.5%和100%。结论 320排CTA图像质量好,诊断冠心病准确可靠。     

64排螺旋CT冠脉成像在冠心病诊断中的应用

目的 评价64排螺旋CT冠状动脉(冠脉)成像(CTA)在冠心病诊断中的应用价值.方法 以选择性冠脉造影(SCA)结果为金标准,采用64排螺旋CT对68例疑诊冠心病患者的冠脉主干及主要分支272节段进行重建和分析,评价其诊断冠心病的灵敏度和特异度.结果 CTA能够清晰显示冠脉主干及其分支狭窄、钙化、开口起源异常及桥血管病变,CTA发现钙化病变52节段,SCA仅发现钙化病变35节段.CTA诊断冠脉病变的灵敏度96.33%,特异度98.16%,阳性预测值97.22%,阴性预测值97.56%.其中对左主干、左前降支病变及＞75%的病变灵敏度最高,分别达到100%和94.4%.结论 CTA对冠脉狭窄病变、桥血管、开口畸形、支架管腔均显影良好,对冠心病诊断有较高的准确性,对钙化病变诊断率优于冠脉造影,可以作为冠心病高危人群无创性筛选检查及冠脉支架术后随访手段.     

Accuracy of automated software-guided detection of significant coronary artery stenosis by CT angiography: comparison with invasive catheterisation

Purpose

True automated detection of coronary artery stenoses might be useful whenever expert evaluation is not available, or as a “second reader” to enhance diagnostic confidence. We evaluated the accuracy of a PC-based stenosis detection tool alone and combined with expert interpretation.

Methods

One hundred coronary CT angiography datasets were evaluated with the automated software alone, by manual interpretation (axial images, multiplanar reformations and maximum intensity projections in free double-oblique planes), and by expert interpretation aware of the automated findings. Stenoses ≥?50 % were noted per-vessel and per-patient, and compared with invasive angiography.

Results

Automated post-processing was successful in 90 % of patients (88 % of vessels). When excluding uninterpretable datasets, per-patient sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 89 %, 79 %, 74 % and 92 % (per-vessel: 82 %, 85 %, 48 % and 96 %). All 100 datasets were evaluable by expert interpretation. Per-patient sensitivity, specificity, PPV and NPV were 95 %, 95 %, 93 % and 97 % (per-vessel: 89 %,98 %, 88 % and 98 %). Knowing the results of automated interpretation did not improve the performance of expert readers.

Conclusion

Automated off-line post-processing of coronary CT angiography shows adequate sensitivity, but relatively low specificity in coronary stenosis detection. It does not increase accuracy of expert interpretation. Failure of post-processing in 10 % of all patients necessitates additional manual image work-up.

Key Points

? Coronary CT angiography is increasingly used for detection of coronary artery stenosis ? Computer assisted diagnosis might facilitate and speed up interpretation ? Performance in properly segmented cases compared favourably with manual image interpretation ? However, automated segmentation failed in about 10 % of cases ? Manual reading is still mandatory; computer assisted diagnosis can provide a useful second read     

双源CT“双低”成像在冠状动脉桥血管的初步研究

目的：评价双源C T“双低”成像在冠状动脉桥血管检查的可行性和有效性。方法连续入组38例冠状动脉搭桥术后患者。冠状动脉CT血管造影（CCTA）采用前瞻性心电触发序列扫描、低管电压结合迭代算法,采用等渗低浓度碘对比剂碘克沙醇（270mgI／ml）。其中20例患者进行了有创冠状动脉造影（CAG ）检查。两位评价者评价桥血管的CTA图像质量和是否存在显著狭窄（≥50％）和闭塞,以CAG为参照标准,评价CCTA诊断桥血管显著狭窄和闭塞的敏感性、特异性、阳性预测值（PPV）和阴性预测值（NPV）。结果38例患者共评价76支桥血管,按照分段,评价387段桥血管,可诊断的血管段达到99．5％（385／387）。20例造影患者中以CAG为参照标准,CCTA诊断桥血管显著狭窄的敏感性、特异性、PPV和NPV分别为100％（4／4）、97．6％（40／41）、80．0％（4／5）和100％（40／40）。CCTA准确诊断了9支闭塞的桥血管。结论双源CT“双低”扫描方案对于桥血管检查具有可行性,该扫描方案可以显著降低辐射剂量和对比剂的碘负荷而保证诊断所需图像质量。对桥血管显著狭窄和闭塞的诊断准确性较高。     

16-detector row computed tomographic coronary angiography in patients undergoing evaluation for aortic valve replacement: comparison with catheter angiography

AIM: To evaluate the diagnostic accuracy of 16-detector row computed tomography (CT) in assessing haemodynamically significant coronary artery stenoses in patients under evaluation for aortic stenosis pre-aortic valve replacement. SUBJECTS AND METHODS: Forty consecutive patients under evaluation for severe aortic stenosis and listed for cardiac catheterization before potential aortic valve replacement underwent coronary artery calcium (CAC) scoring and retrospective electrocardiogram (ECG)-gated multi-detector row computed tomographic coronary angiography (MDCTA) using a GE Lightspeed 16-detector row CT within 1 month of invasive coronary angiography (ICA) for comparative purposes. All 13 major coronary artery segments of the American Heart Association model were evaluated for the presence of > or =50% stenosis and compared to the reference standard. Data were analysed on a segment-by-segment basis and also in "whole patient" terms. RESULTS: A total of 412/450 segments from 35 patients were suitable for analysis. The overall accuracy of MDCTA for detection of segments with > or =50% stenosis was high, with a sensitivity of 81.3%, specificity 95.0%, positive predictive value (PPV) 57.8%, and negative predictive value (NPV) 98.4%. On a "whole-patient" basis, 100% (19/19) of patients with significant coronary disease were correctly identified and there were no false-negatives. Excluding patients with CAC >1000 from the analysis improved the accuracy of MDCTA to: sensitivity 90%, specificity 98.1%, PPV 60%, NPV 99.7%. CONCLUSION: Non-invasive 16-detector row MDCTA accurately excludes significant coronary disease in patients with severe aortic stenosis undergoing evaluation before aortic valve replacement and in whom ICA can therefore be avoided. Its segment-by-segment accuracy is improved further if CAC>1000 is used as a gatekeeper to MDCTA.     

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.     

CT ​Evaluation ​by ​Artificial ​Intelligence ​for ​Atherosclerosis,Stenosis and Vascular ​Morphology ​(CLARIFY): ​A ​Multi-center,international study

BackgroundAtherosclerosis evaluation by coronary computed tomography angiography (CCTA) is promising for coronary artery disease (CAD) risk stratification, but time consuming and requires high expertise. Artificial Intelligence (AI) applied to CCTA for comprehensive CAD assessment may overcome these limitations. We hypothesized AI aided analysis allows for rapid, accurate evaluation of vessel morphology and stenosis.MethodsThis was a multi-site study of 232 patients undergoing CCTA. Studies were analyzed by FDA-cleared software service that performs AI-driven coronary artery segmentation and labeling, lumen and vessel wall determination, plaque quantification and characterization with comparison to ground truth of consensus by three L3 readers. CCTAs were analyzed for: % maximal diameter stenosis, plaque volume and composition, presence of high-risk plaque and Coronary Artery Disease Reporting & Data System (CAD-RADS) category.ResultsAI performance was excellent for accuracy, sensitivity, specificity, positive predictive value and negative predictive value as follows: >70% stenosis: 99.7%, 90.9%, 99.8%, 93.3%, 99.9%, respectively; >50% stenosis: 94.8%, 80.0%, 97.0, 80.0%, 97.0%, respectively. Bland-Altman plots depict agreement between expert reader and AI determined maximal diameter stenosis for per-vessel (mean difference −0.8%; 95% CI 13.8% to −15.3%) and per-patient (mean difference −2.3%; 95% CI 15.8% to −20.4%). L3 and AI agreed within one CAD-RADS category in 228/232 (98.3%) exams per-patient and 923/924 (99.9%) vessels on a per-vessel basis. There was a wide range of atherosclerosis in the coronary artery territories assessed by AI when stratified by CAD-RADS distribution.ConclusionsAI-aided approach to CCTA interpretation determines coronary stenosis and CAD-RADS category in close agreement with consensus of L3 expert readers. There was a wide range of atherosclerosis identified through AI.     

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.     

64MDCT冠状动脉成像在冠心病诊断中的应用价值

目的探讨64层螺旋CT冠状动脉成像在冠心病诊断中的应用价值。方法随机选择我院2010年10月～2011年12月46例由于胸痛、胸闷就诊的患者,分别给予64层螺旋CT冠状动脉成像与选择性冠状动脉造影,以选择性冠状动脉造影检查的结果为“金标准”,分析64层螺旋CT冠状动脉成像在冠心病诊断中的敏感性、特异性及准确率。结果MDCTCA共检查节段586个,直径在1．5mm以上有504个,检出狭窄程度≥50％的28例,漏诊1例,误诊2例。与冠状动脉造影检查结果相比,64层螺旋CT冠状动脉成像检查的敏感性为96．3％（26／27例）,特异性为89．5％（17／19例）,准确性为93．5％（43／46例）,阳性预测值为92．9％（26／28）,阴性预测值为94．4％（17／18）,差异无统计学意义（P〉0．05）。结论64层螺旋CTCA具有无创、安全、经济且操作简便的优点,对冠状动脉病变诊断具有良好的敏感度和特异性,是一种可广泛应用于冠心病的筛选和诊断的检查方法。     

CCTA技术对冠状动脉狭窄及其钙化斑块的评估

冠状动脉CT血管成像（CCTA）是一种可无创检测冠状动脉粥样硬化性疾病的成像手段,已成为临床筛查及诊断冠心病的首要检查方法。但对于钙化严重的冠状动脉节段,CCTA的特异性及阳性预测值偏低,可导致病人过度治疗,因此限制了CCTA的临床应用。综述钙化斑块伪影对CCTA的影响,并就CCTA对冠状动脉狭窄准确评估的相关技术进展进行分析,以利于临床诊断中提高CCTA对冠状动脉狭窄率的评估。     

256层CT诊断冠状动脉狭窄与CCA对照分析

目的:评价256层CT诊断冠状动脉狭窄的价值,并与常规冠状动脉造影(CCA)对照分析.方法:80例行256层CT冠状动脉造影(CCTA)及CCA检查者纳入研究.半定量分析CCTA诊断冠状动脉狭窄程度,并以CCA结果为参考标准.评估256层CT诊断冠状动脉狭窄的敏感度、特异度、阳性预测值、阴性预测值和准确性.同时分析25...     

多层螺旋CT和三维屏气MR冠状动脉成像的对比研究

目的比较16层螺旋CT（16 multi-detector CT,16-MDCT）冠状动脉血管造影（CTA）和三维屏气冠状动脉MR血管造影（MRA）的图像质量以及诊断冠状动脉显著性狭窄（＞50%）的准确性.方法40例疑有冠心病患者在3 d内均行冠状动脉CTA和MRA检查,其中31例患者在2周内行冠状动脉造影检查.将冠状动脉分成9个节段（右冠状动脉近、中、远段,左冠状动脉主干,前降支近、中、远段和旋支近、远段）,由2名影像科医生共同对各个节段的图像质量按0～4级评分,比较CTA和MRA上各个节段的图像质量.以冠状动脉造影为标准,计算并比较CTA和MRA诊断31例冠状动脉显著性狭窄（＞50%）各项准确性指标.结果CTA在右冠状动脉中段的图像质量低于MRA,右冠状动脉近段二者无区别,其他节段均优于MRA.冠状动脉造影显示31例患者共有43个节段狭窄＞50%,CTA和MRA分别正确诊断出36和27个,其敏感性、特异性、阳性预测值和阴性预测值分别为83%、84%、49%、97%和63%、90%、55%、93%.结论除右冠状动脉中段,CTA大部分节段的图像质量优于MRA.CTA诊断冠状动脉显著性狭窄的敏感性高于MRA,但特异性低于MRA.冠状动脉CTA和MRA均表现了较高的阴性预测值,对排除冠状动脉狭窄具有临床价值.     

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。     

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。     

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.     

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.