低辐射剂量冠状动脉成像的研究进展

冠状动脉CT成像（CCTA）已成为一种准确率较高的评价冠状动脉解剖形态的无创手段,但是检查产生的高剂量辐射越来越受到人们的普遍关注。如何在尽可能降低辐射剂量的同时保证诊断质量已成为CCTA的研究热点。笔者就该方面近年的研究进展做一综述。     

Coronary plaque imaging by coronary computed tomography angiography

Coronary computed tomography angiography (CTA) has become the useful noninvasive imaging modality alternative to the invasive coronary angiography for detecting coronary artery stenoses in patients with suspected coronary artery disease (CAD). With the development of technical aspects of coronary CTA, clinical practice and research are increasingly shifting toward defining the clinical implication of plaque morphology and patients outcomes by coronary CTA. In this review we discuss the coronary plaque morphology estimated by CTA beyond coronary angiography including the comparison to the currently available other imaging modalities used to examine morphological characteristics of the atherosclerotic plaque. Furthermore, this review underlies the value of a combined assessment of coronary anatomy and myocardial perfusion in patients with CAD, and adds to an increasing body of evidence suggesting an added diagnostic value when combining both modalities. We hope that an integrated, multi-modality imaging approach will become the gold standard for noninvasive evaluation of coronary plaque morphology and outcome data in clinical practice.     

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。     

The Journal of Cardiovascular Computed Tomography year in review - 2018

Since the introduction of ≥64 detector row coronary computed tomography angiography (CCTA) as a noninvasive imaging modality, various clinical trials have established its diagnostic performance and prognostic significance when compared to other anatomic and functional tests for coronary artery disease (CAD). CCTA has been increasingly utilized for a wide range of clinical scenarios, driven by both advances in technology as well as data showing improvement in outcomes. Accumulating evidence has continually refined and supported the central role of CCTA within clinical care, and this year has witnessed continued evolution of the application of CCTA within healthcare and translational research. The purpose of the present review is to summarize the year of the Journal of Cardiovascular Computed Tomography (JCCT), highlighting the evidence base supporting the appropriate application of cardiac computed tomography across numerous clinical domains.     

回顾性心电门控CT在儿童川崎病冠状动脉损伤评估中的应用

目的探讨回顾性心电门控冠状动脉CT血管造影(CCTA)评估川崎病(KD)患儿冠状动脉病变的可行性及成像技术,并与经胸超声心动图(TTE)对比研究。方法回顾性分析2014年1月—2018年7月经临床确诊的32例KD患儿资料[男19例,女13例,年龄2个月～10岁,平均(3.89±3.19)岁],所有患儿均行回顾性心电门控CT及TTE检查,由2名影像科医师独立对CT成像质量、重组时相,冠状动脉病变的数目、位置、大小及危险性分级进行测量和观察,并与TTE结果对比研究;计算所有患儿接受的有效辐射剂量。对两种方法测得的数据进行配对t检验及χ~2检验,一致性分析采用Kappa检验。结果CCTA可评价冠状动脉节段比为93.8%(120/128),共观察到46个冠状动脉瘤、33支瘤样扩张及1支动脉壁钙化,其中7个动脉瘤、5支瘤样扩张及1支动脉壁钙化TTE检查时未发现。两种方法对左右冠状动脉主干直径的测量值及对各节段冠状动脉损伤检出的阳性率的差异均无统计学意义(P0.05)。冠状动脉最优化重组相位位于45%及75%～85%两个相位间。2名放射科医师对所有CCTA影像质量主观评分一致性好(κ=0.87),对KD危险度分级完全一致。32例患儿的有效辐射剂量为(3.22±1.57)mSv。结论回顾性心电门控CCTA检查可以在降低辐射剂量的基础上取得良好的成像效果,能够精确地观察冠状动脉的全程各段及病变程度,对儿童KD的评价及其危险分级具有重要的临床价值。     

256层螺旋CT低剂量冠状动脉成像研究

目的：评价256层CT前瞻性心电门控冠状动脉成像的图像质量与辐射剂量,并与回顾性心电门控对照分析。方法 共200例患者纳入研究。100例行前瞻性心电门控的患者分为2组：(1)心率≤70次/min( bpm )50例,数据采集时间窗设在心动周期的75％期相（A组）;(2)心率＞70 bpm 50例,数据采集时间窗设在心动周期的45％期相,包含5％宽容度（B组）。另外100例行回顾性心电门控的患者亦分为2组：(3)心率≤70 bpm 50例,最大管电流输出设在75％期相（C组）;(4)心率＞ 70 bpm 50例,最大管电流输出设在45％与75％期相（D组）。所有患者由数字表法随机分组。采用4分法半定量分析冠状动脉节段及整体评分。采用Mann-Whitney U检验比较组间图像质量,采用t检验比较组间的辐射剂量;并对100例前瞻性心电门控检查者冠状动脉图像质量与平均心率进行ROC分析及相关分析。结果 在共2338个冠状动脉节段中,图像质量优秀或良好（评分1或2分）者A组中达到96.5％( 585/606),B组为77.7％(445/573),C组为96.1％( 548/570),D组为85.7％ (505/589),冠状动脉节段图像质量A组与C组比较差异无统计学意义（Z＝ -1.351,P＞0.05）;B组和D组差异有统计学意义（Z＝-2.236,P＜0.05）。前瞻性心电门控检查ROC分析及相关分析显示,平均心率与冠状动脉图像质量密切相关(r＝0.577,P＜0.01),平均心率78 bpm可做为满足诊断图像的最高临界点心率（ROC曲线下面积为0.827,P＜0.05）。A组[(2.6±0.5)mSv]相对C组[(10.6 ±2.3) mSy]平均辐射剂量减少75％,B组[(4.0 ±0.7) mSy]相对D组[ (13.0±1.4) mSy]平均辐射剂量减少69％。结论 256层CT低剂量前瞻性心电门控成像可获得与回顾性心电门控相似的满足诊断需要的图像质量,并可应用于高心率检查者。     

CT-SYNTAX评分在复杂冠状动脉疾病心肌血运重建决策中的应用进展

复杂冠状动脉疾病（CAD）心肌血运重建治疗策略的选择是临床医师关注的问题,基于有创冠状动脉造影（ICA）的SYNTAX评分是当前重要的临床指导依据。随着冠状动脉CT血管成像（CCTA）的普及,基于CCTA的SYNTAX评分（CT-SYNTAX）成为研究热点。基于CCTA的血流储备分数（FFR_CT）可提供CAD的功能学信息,实现了CT-SYNTAX评分从解剖学向功能学的提升。就CT-SYNTAX评分在复杂CAD病人治疗策略中应用的研究进展予以综述。     

The expanding role of left ventricular functional assessment using gated myocardial perfusion SPECT: the supporting actor is stealing the scene

Background Gating of single-photon emission computed tomography (SPECT) has significantly improved the reliability and diagnostic accuracy of myocardial perfusion imaging. The functional parameters derived from this technique, mainly left ventricular volumes and ejection fraction, have been demonstrated to be accurate and reproducible. They are able to increase the detection of severe and extensive coronary artery disease and show a significant incremental prognostic power over perfusion abnormalities. Therefore, the importance given to gated SPECT functional data has progressively grown. Discussion This circumstance has further expanded the indications for myocardial perfusion imaging and strengthened its position among the different imaging modalities. Moreover, several studies show that the evaluation of ventricular function may have a leading part in justifying the execution of perfusion scintigraphy in various clinical conditions. Aim Aim of this review is to describe this evolution of gated SPECT functional assessment from a supporting rank with respect to perfusion, to a main actor position in the field of cardiac imaging.     

Diagnosing coronary artery disease with hybrid PET/CT: It takes two to tango

The noninvasive diagnosis of coronary artery disease (CAD) is a challenging task. Although a large armamentarium of imaging modalities is available to evaluate the functional consequences of the extent and severity of CAD, cardiac perfusion positron emission tomography (PET) is considered the gold standard for this purpose. Alternatively, noninvasive anatomical imaging of coronary atherosclerosis with coronary computed tomography angiography (CCTA) has recently been successfully implemented in clinical practice. Although each of these diagnostic approaches has its own merits and caveats, functional and morphological imaging techniques provide fundamentally different insights into the disease process and should be considered to be complementary rather than overlapping. Hybrid imaging with PET/CT offers the possibility to evaluate both aspects nearly simultaneously, and studies have demonstrated that such a comprehensive assessment results in superior diagnostic accuracy, better prognostication, and helps in guiding clinical patient management. The aim of this review is to discuss the value of stand-alone CCTA and PET in CAD, and to summarize the available data on the surplus value of hybrid PET/CT including its strengths and limitations.     

Comprehensive morphologic and functional imaging of heart transplant patients: first experience with dynamic perfusion CT

Objectives

We aimed to assess the diagnostic performance of a combined protocol with coronary computed tomography angiography (CCTA) and stress CT perfusion imaging (CTP) in heart transplant patients for comprehensive morphological and functional imaging.

Methods

In this prospective study, 13 patients undergoing routine follow-up 8±6 years after heart transplantation underwent CCTA and dynamic adenosine stress CTP using a third-generation dual-source CT scanner, cardiac magnetic resonance (MR) adenosine stress perfusion imaging at 1.5 T, and catheter coronary angiography. In CCTA stenoses >50% luminal diameter narrowing were noted. Myocardial perfusion deficits were documented in CTP and MR. Quantitative myocardial blood flow (MBF) was calculated with CTP. Left ventricular ejection fraction was determined on cardiac MR cine images. Radiation doses of CT were determined.

Results

One of the 13 patients had to be excluded because of severe motion artifacts. CCTA identified three patients with stenosis >50%, which were confirmed with catheter coronary angiography. CTP showed four patients with stress-induced myocardial hypoperfusion, which were confirmed by MR stress perfusion imaging. Quantitative analysis of global MBF showed lower mean values as compared to known reference values (MBF under stress 125.5 ± 34.5 ml/100 ml/min). Average left ventricular ejection fraction was preserved (56 ± 5%).

Conclusions

In heart transplant patients, a comprehensive CT protocol for the assessment of morphology and function including CCTA and CTP showed good concordance to results from MR perfusion imaging and catheter coronary angiography.

Key Points

? Stress CT perfusion imaging enables the detection of myocardial ischemia ? CT myocardial perfusion imaging can be combined with coronary computed tomography angiography ? Combining perfusion and coronary CT imaging is accurate in heart transplant patients ? CT myocardial perfusion imaging can be performed at a reasonable radiation dose

     

低剂量冠状动脉CTA在高心率及心律失常病人中的研究现状

随着医学影像技术的不断发展,冠状动脉CT血管成像（CTA）已成为临床上筛选冠心病的重要检查方法,并广泛应用于临床。高心率以及心律失常以往一直被视为该项检查的瓶颈,随着多层螺旋CT的快速发展,两者不再成为冠状动脉CT检查的禁忌证,而且在降低辐射剂量的同时也能获得良好的影像质量。就冠状动脉CTA低剂量扫描在高心率及心律失常病人中的应用现状及最新进展予以综述。     

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。     

Pre-procedural planning of coronary revascularization by cardiac computed tomography: An expert consensus document of the Society of Cardiovascular Computed Tomography

Coronary CT angiography (CCTA) demonstrated high diagnostic accuracy for detecting coronary artery disease (CAD) and a key role in the management of patients with low-to-intermediate pretest likelihood of CAD. However, the clinical information provided by this noninvasive method is still regarded insufficient in patients with diffuse and complex CAD and for planning percutaneous coronary intervention (PCI) and surgical revascularization procedures. On the other hand, technology advancements have recently shown to improve CCTA diagnostic accuracy in patients with diffuse and calcific stenoses. Moreover, stress CT myocardial perfusion imaging (CT-MPI) and fractional flow reserve derived from CCTA (CT-FFR) have been introduced in clinical practice as new tools for evaluating the functional relevance of coronary stenoses, with the possibility to overcome the main CCTA drawback, i.e. anatomical assessment only. The potential value of CCTA to plan and guide interventional procedures lies in the wide range of information it can provide: a) detailed evaluation of plaque extension, volume and composition; b) prediction of procedural success of CTO PCI using scores derived from CCTA; c) identification of coronary lesions requiring additional techniques (e.g., atherectomy and lithotripsy) to improve stent implantation success by assessing calcium score and calcific plaque distribution; d) assessment of CCTA-derived Syntax Score and Syntax Score II, which allows to select the mode of revascularization (PCI or CABG) in patients with complex and multivessel CAD.The aim of this Consensus Document is to review and discuss the available data supporting the role of CCTA, CT-FFR and stress CT-MPI in the preprocedural and possibly intraprocedural planning and guidance of myocardial revascularization interventions.     

胸痛影像学评估的前瞻性多中心研究及进展

胸痛评估的前瞻性多中心影像学研究（PROMISE）始于2010年,该研究分析症状稳定的疑似冠心病病人首选冠状动脉CT血管成像（CCTA）进行解剖学检查或首选无创性功能学检查,旨在探究病人临床结局的差异。PROMISE研究了CCTA、功能学检查及冠状动脉钙化积分和CT血流储备分数等无创性检查方法对疑似冠心病的稳定性胸痛病人的预后价值,并探讨了生物标志物、年龄、性别、代谢性疾病对稳定性胸痛病人的影响。此外,PROMISE开发并验证了风险分层模型和个体化选择检查方法的工具。PROMISE对CCTA和功能学检查的应用产生了很大的影响,为疑似冠心病病人无创检查方法的选择提供了重要循证依据。     

CT血管造影在诊断功能相关性冠状动脉狭窄中的应用

目的以 SPECT 心肌灌注显像(MPI)为参考,评价 CT 血管造影检测功能相关性冠状动脉狭窄(FRCS)的诊断效能.资料与方法2005-11~2011-03在天津医科大学心血管病临床学院同期(30d 内)行冠状动脉 CT血管造影(CCTA)和 MPI 的504例可疑或确诊冠状动脉疾病患者,以 CCTA冠状动脉狭窄≥50%并伴有相应血管支配区域 MPI 灌注缺损作为诊断 FRCS的参考标准.以病例或血管为观察对象,分别计算 CCTA 冠状动脉狭窄≥50%或≥75%时检测 FRCS 的诊断效能.结果以病例为观察对象,CCTA 冠状动脉狭窄≥50%或≥75%检测 FRCS 的灵敏度、特异性、阳性预测值和阴性,预测值分别为67.2%和35.8%、84.7%和97.3%、40.2%和66.7%、94.4%和90.8%,差异均有统计学意义(P<0.05);以血管为观察对象,CCTA 冠状动脉狭窄≥50%或≥75%检测 FRCS 的灵敏度、特异性、阳性预测值和阴性预测值分别为70.2%和33.7%、95.4%和99.0%、42.9%和60.0%、98.5%和97.0%,差异均有统计学意义(P<0.05).结论 CCTA 具有较佳的排除 FRCS 的能力.当冠脉狭窄≥50%时,CCTA 虽然对 FRCS 检测灵敏度较高,但其阳性预测值相对较差.当冠脉狭窄≥75%时,CCTA 检测 FRCS 的阳性预测值有一定的提高.     

智能期相选择重组在高心率儿童冠状动脉CTA中的应用

目的 评估智能期相（SP）选择重组技术用于高心率儿童冠状动脉CT血管成像（CCTA）的可行性及影像质量。方法 收集2018年1月-4月拟诊为川崎病冠状动脉瘤或冠状动脉起源发育异常要求行CCTA检查的患儿28例（冠状动脉血管及其分支共420支）,其中男13例,女15例,平均年龄（4.4±3.0）岁,平均心率（99.2±18.0）次/min。采用GE Revolution 256层宽体CT行CCTA检查,对扫描原始数据分别采用SP选择技术（SP组）和手动期相选择技术（MP组）对影像重组。重组影像由2位放射医师采用美国心脏协会推荐的冠状动脉15分段法进行评分,评分采用4分制。采用配对t检验比较MP组和SP组重组影像中冠状动脉及其分支的主观评分。2位评分者之间的一致性采用Kappa检验分析。结果 CCTA共显示386支冠状动脉血管及其分支,其中S10节段有15例患儿显示,S14节段有24例显示,S15节段有11例显示,其余血管节段在28例中全部显示。2位医师影像评分一致性中等（κ=0.62）。重组影像主观评分均满足诊断要求,其中MP组对S3、S9、S14段的评分高于SP组（P<0.05）,其余各段评分差异无统计学意义（P>0.05）。28例患儿中SP 与MP的重组期相诊断一致率为85.7%（24/28）。结论 使用SP选择重组技术对高心率儿童行CCTA检查可以获得满足诊断的影像质量,同时可以节省时间提高工作效率。     

Cardiac CT: coronary arteries and beyond

Multi-detector-row computed tomography (MDCT) has emerged as a rapidly developing method for non-invasive imaging of the heart. An understanding of ECG synchronization, contrast material administration, patient preparation and image post-processing is needed to optimize image quality. The basic technical principles and essentials of these technical basics are described here. Correctly applied cardiac MDCT allows imaging of the coronary arteries including coronary anatomy and stenosis detection. The same is true for evaluation of coronary artery bypass grafts and, to some extent, coronary artery stents. While quantification of total calcified plaque burden has been long established, coronary MDCT allows assessing plaque morphology and constitution. Recent approaches go beyond the coronaries and include evaluation of left ventricular function at rest and myocardial viability. In combination with experimental approaches for assessing aortic valve function and myocardial perfusion imaging, cardiac MDCT offers the potential for a comprehensive examination of the heart using a single breath-hold examination.     

State of the art of coronary computed tomography angiography

ObjectivesThe aim of this paper is to evaluate contrast media (CM) bolus geometry and opacification patterns in the coronary arteries with particular focus on patient, scanner and safety considerations during coronary computed tomography angiography (CCTA).Key findingsThe rapid evolution of computed tomography (CT) technology has seen this imaging modality challenge conventional coronary angiography in the evaluation of coronary artery disease. Increases in spatial and temporal resolutions have enabled CCTA to become the modality of choice when evaluating the coronary vascular tree as an alternative in the diagnostic algorithm for acute chest pain. However, these new technologic improvements in scanner technology have imposed new challenges for the optimisation of CM delivery and image acquisition strategies.ConclusionUnderstanding basic CM-imaging principles is essential for designing optimal injection protocols according to each specific clinical scenario, independently of scanner technology.Implications for practiceWith rapid advances in CT scanner technology including faster scan acquisitions, the risk of poor opacification of coronary vasculature increases significantly. Therefore, awareness of CM delivery protocols is paramount to consistently provide optimal image quality at a low radiation dose.     

人工智能在心血管CT成像中的新进展

随着计算机技术的进步与影像设备性能的大幅提升,人工智能（AI）已成为医学研究的热点。目前,AI在心血管CT成像领域也已广泛应用,可以用于冠状动脉CT血管成像（CCTA）影像质量的优化、心血管组织自动分割、自动计算冠状动脉钙化积分（CACS）、实现冠状动脉狭窄的自动化识别与检测,此外还可以识别心肌缺血、预测心血管事件等。介绍常用的AI技术及其相关的术语,综述当前AI在心血管CT成像中的应用现状,并分析AI应用的局限和未来的展望。     

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.