256层CT冠脉成像对壁冠状动脉管腔变化的观察与分析

目的探讨256层CT冠脉成像评价心肌桥血管管腔变化的临床应用价值。方法随机抽取我院2010年12月～2012年1月进行冠状动脉CTA检查患者200例作为研究对象,对比剂使用碘海醇65～80ml,流速5.0～5.5ml/s,采用Surestar技术跟踪扫描,阈值150HU;采用多种图像后处理技术:容积重组(VR)、多平面重组(MPR)、曲面重组(CPR)及最大密度投影(MIP),对壁冠状动脉采用45%时相(收缩期)、75%时相(舒张期)进行观察。结果 200例受检者中,心肌桥78例(39%),其中左前降支62例(79.5%),浅表型52例(66.7%),深在型26例(33.3%),浅表型收缩期管腔狭窄15%～20%,平均16.5%,深在型收缩期管腔狭窄40%～70%,平均52%。结论 256层CT冠脉成像能够清晰显示心肌桥形态,通过收缩期和舒张期成像可对壁冠状动脉管腔压缩程度进行评价,为临床提供有价值的血液动力学方面的信息。     

Vieussens 环的 CTA 显示及临床价值

前降支的分支左圆锥支与右冠状动脉右圆锥支互相吻合形成动脉环,称为 Vieussens 环,是左右冠状动脉之间重要的侧支循环[1-2]。由于其走行大部分位于脂肪间隙之间,且管径细小,常规扫描时不能显示。但由于先天原因或在某些病理情况下,Vieussens 环迂曲、增粗,就会显示出来。多排螺旋 CT 尤其是256排 CT 的时间分辨率大大提升,使得冠状动脉成像更加清晰,细节显示较为全面,对 Vieussens 环的显示更加全面、准确[3]。本文回顾性分析15例成人 Vieussens 环的影像学表现,探讨256层螺旋 CT 血管造影(CTA)技术在本病诊断中的价值。为临床尽快选择正确的治疗方案提供较为明确的帮助[4]。     

256层CT血管成像对冠状动脉瘘的诊断价值

目的 探讨256层CT血管成像(CTA)对冠状动脉瘘(CAF)的诊断价值.方法 回顾性分析CAF 18例,对原始图像进行多平面重组(MPR)、曲面重组(CPR)、最大密度投影(MIP)及容积重建(VR)等后处理.结果 18例CAF中冠状动脉分支血管瘘入肺动脉5例;瘘入冠状静脉窦5例;瘘入右心房3例;瘘入左心房3例;瘘入右心室2例.5例冠状动脉 -肺动脉瘘可观察到畸形血管向肺动脉内供血,肺动脉主干内均可见对比剂呈"喷射"或"浓染"征.主肺动脉旁形成丛状或蔓藤状血管网2例.供血动脉区动脉瘤形成3例.结论 256层冠状动脉CTA能准确显示CAF变异血管的解剖细节及血流动力学改变情况,运用多种重建技术能够直观地显示CAF的畸形血管形态.     

256层CTA对下肢动脉不同部位闭塞侧支循环的评价

目的应用256层CT血管成像(CTA)探讨下肢动脉不同部位闭塞侧支循环的特征及临床应用价值。方法对43例下肢动脉闭塞患者临床资料进行回顾性分析,所有病例行下肢动脉CTA检查,利用多种后处理技术观察下肢动脉闭塞的部位,观察相应血管侧支循环形成情况,并与DSA进行比较。结果 43例下肢动脉不同部位闭塞侧支循环途径包括:腹壁动脉(14例)、旋髂浅动脉(14例)、腰动脉(6例)、股深动脉(13例)、膝关节支(16例)、穿支动脉(10例),CTA对其显示率分别为100%、100%、67%、100%、69%、30%;DSA显示率分别为100%、100%、83%、100%、88%、80%。结论 256层CTA能清晰显示下肢动脉不同部位闭塞的侧支循环形成情况,为下肢动脉闭塞症患者治疗方式的选择和预后判断具有肯定的临床应用价值。     

肠系膜上动脉多层螺旋CT血管成像研究

目的:探讨多层CT血管成像不同后处理技术显示肠系膜上动脉(SMA)分支的能力.材料和方法:正常上腹部20例用16层CT动脉期追踪扫描,进行图像后处理,得到多平面重建(MPR)、血管外型观察(VS)、最大密度投影(MIP)图像.评价三种方法对SMA的显示情况.结果:中结肠动脉各级分支,显示情况MPR优于MIP或VS.空、回肠动脉1、2、3级分支三种方法显示情况相似,4级分支的显示率MPR＞MIP＞VS,显示程度均差.SMA 4级以上分支MPR显示率超过50%.结论:多层CT血管成像可获得良好的SMA图像.MPR结合VS或MIP能很好地显示SMA的细小分支.     

64层螺旋CT冠状动脉成像图像质量控制研究

目的 探讨CT冠状动脉成像图像质量控制的临床应用.方法 102例患者采用64层螺旋CT心电门控冠状动脉成像,男68例,女34例,心率<65次/min为Ⅰ组,65～75次/min为Ⅱ组,>75次/min为Ⅲ组,每位患者的冠状动脉分为12血管段用于图像质量分析.测量冠状动脉各分支图像无伪影显示率和各分支近段和远段对比噪声比.结果 (1)所有患者总体评估结果显示,94.0%冠状动脉血管段显示无伪影.Ⅰ组冠状动脉分支无伪影显示率98.2%,Ⅱ组冠状动脉分支无伪影显 示率95.3%,Ⅲ组冠状动脉分支无伪影显示率85.0%;(2)所有冠状动脉分支平均对比噪声比为14.7±4.1.结论 64层螺旋CT有高质量的冠状动脉图像,心率影响冠状动脉图像,低心率仍是图像质量保证的关键因素.     

影响16层螺旋CT冠状动脉成像质量技术因素的探讨

目的:探讨16层螺旋CT冠状动脉血管成像技术。方法:272例受检者行16层螺旋CT冠状动脉血管成像检查,采用电影扫描序列,层厚为1.25mm或0.625mm,螺距为0.275:1,对比剂1.5~2ml/kg,注射速率3~4ml/s,采用容积再现(VR)、多平面重建(MPR)、曲面重建(CPR)和仿真内窥镜(VE)进行图像后处理重建,显示冠状动脉主干及其主要分支。结果:心率对图像质量的影响较大(χ2=23.936,P<0.01),心率平稳,心率在55~75次/min,MSCT对冠状动脉主干及主要分支显示率80.3%达到诊断要求,心率大于90次/分时,冠状动脉的主要分支显示不清;重建相位窗在55%、65%和75%之间显示一、二级高质量冠状动脉图像的例数无显著性差异(χ2=1.980,P>0.05),选择重建相位窗为75%可提高工作效率;采用扫描层厚为0.625mm或1.25mm(重建间隔为0.625)所得到的图像质量可满足影像及临床诊断需要(χ2=0.833,P>0.05),选择扫描层厚1.25mm所获得图像的信噪比及移动伪影明显减少;采用3.5ml/s或4ml/s注射速率图像重建后达到一、二级水平的图像质量基本接近(χ2=0.268,P>0.05),使用注射速率为3.5ml/s,显示冠状动脉清晰且受腔静脉伪影少。结论:心率平稳且小于75次/min,使用合适的重建相位窗、对比剂及扫描参数,MSCT可满意显示冠状动脉主干及主要分支,可作为冠状动脉粥样硬化疾患的筛选,对血管搭桥和内支架放置术后复查的评价有较高临床价值。     

64层螺旋CT冠状动脉成像在冠状动脉搭桥术后的应用

目的：探讨64层螺旋CT冠状动脉造影在冠状动脉搭桥术后的应用价值。方法：24例冠状动脉搭桥术后患者在心电门控技术下采用64层螺旋CT行冠状动脉造影扫描,将所得原始数据进行容积再现、最大密度投影、曲面重建和多平面重建等图像后处理,全面观察桥血管及冠脉狭窄情况。结果：24例冠状动脉搭桥术的患者共有38条桥血管,其CTA图像均能清晰显示,其中5支桥血管轻度狭窄,6支桥血管严重狭窄。结论：64层螺旋CTA作为一种无创性的检查,在冠状动脉搭桥术后随访中具有很高的临床应用价值。     

256层与64层螺旋CT在透析患者上肢CT血管成像中的对比研究

目的比较256层与64层螺旋 CT 在慢性肾衰竭透析患者上肢 CT 血管成像(CTA)检查中的效果.资料与方法回顾性分析23例上肢动静脉瘘造瘘患者的 CTA 图像,10例行64层螺旋 CT 检查,13例行256层 CT 检查,两组均采用对比剂追踪触发扫描技术.采用多平面重组、最大密度投影、容积成像、曲面重组等技术对扫描数据进行三维重建,比较两组患者的动脉分支级别、血管边缘、静脉干扰评分及瘘口娴熟情况.结果两组总体上均得到了较好的一致性评价;两组对肩部、上臂血管分支级别的显示能力差异无统计学意义(t =-0.96, P>0.05; t =0.19, P>0.05),对前臂、手部分支级别的显示能力差异有统计学意义(t =-3.17, P<0.01; t =-2.74, P<0.05);256层组对肩部、上臂、前臂血管边缘光滑度的显示质量优于64层组(t =-2.40, P<0.05;t =-2.08, P<0.05;t =-2.53, P<0.05);两组各区域静脉干扰评分及瘘口显示情况差异无统计学意义(P>0.05).结论相比于64层螺旋 CT,256层螺旋 CT 在血管、内瘘口、流入流出道的细节显示方面效果更佳.     

CT血管成像结合图像融合技术在肾静脉系统评估中的价值

目的:探讨动脉晚期CT血管成像(CTA)结合图像融合技术在肾静脉系统评估中的价值.方法:46例超声提示肾占位性病变的患者和5例活体供肾者行CT平扫和动脉早期、晚期及实质期三期动态增强扫描.利用动脉晚期的数据进行肾静脉图像重组、动脉早期的数据进行肾动脉图像重组,并将两组图像融合在一起.分析CTA结合图像融合技术对评价肾静脉系统的价值.结果:动脉晚期CTA结合图像融合技术能清楚地显示肾静脉主干的变异,包括环主动脉左肾静脉、腹主动脉后左肾静脉及多条右肾静脉,其显示率分别为15.7%、2.0%和31.4%.且能准确显示肾静脉属支,包括左肾上腺静脉、左性腺静脉、汇入左肾静脉的腰静脉、汇入右肾静脉的右肾上腺静脉及右性腺静脉,其显示率分别为88.2%、88.2%、62.7%、3.9%和2.0%,与利用动脉晚期原始图像结合多平面重组对肾静脉系统的显示情况完全一致.实质期对显示细小属支和交通支有补充作用,对肾静脉的显示明显差于动脉晚期,但两者间差异无显著性意义(P＞0.05).结论:动脉晚期CTA结合图像融合技术不仅能清楚显示肾静脉系统的整体解剖,且能同时显示动静脉系统的解剖信息,在肾脏病变的术前评估中有重要价值.     

~(99)Tc~m-NOET门控心肌灌注SPECT评价冠心病的价值

目的 评价~(99)Tc~m-双(N-乙氧基,N-乙基-二硫代氨基甲酸酯)氮化锝(~(99)Tc~m-NOET)静息门控断层心肌灌注显像对冠心病患者的诊断价值.方法 疑诊为冠心病的45例患者注射925 MBq~(99)Tc~m-NOET后1h用SPECT行静息门控心肌灌注显像,获得舒张未期容积(EDV)、收缩未期容积(ESV)、左室射血分数(LVEF)等心功能参数和舒张末期容积灌注、局部射血分数、局部室壁活动和室壁增厚度4个靶心图.所有患者在1周内行冠状动脉造影,将冠状动脉狭窄≥50%定为病变血管.根据冠状动脉造影结果将其分为心肌梗死组、心肌缺血组和对照组三组.结果 ~(99)Tc~m-NOET静息门控SPECT诊断冠心病的灵敏度和特异度分别为68.42%和83.33%.心肌梗死组的心功能参数[EDV=(129.32±9.14)ml,ESV=(80.97±9.49)ml,LVEF=(40.15±3.28)%]与对照组[EDV=(80.91±3.12)ml,ESV=(30.12±1.79)ml,LVEF=(63.51±1.04)%]相比,统计学差异有显著性(EDV:F=22.103,ESV:F=32.277,LVEF:F=42.604,均为P＜0.01),心肌缺血组的心功能参数[(EDV=(70.83±3.46)ml,ESV=(25.13±2.85)ml,LVEF=(65.55±2.62)%]与对照组相比,统计学差异无显著性意义.心肌梗死组左室心肌共分为460个节段,其中209个节段局部灌注、局部射血分数、局部室壁活动和室壁增厚度4个靶心图均异常.局部灌注异常的节段共328个节段.伴有局部射血分数、局部室壁活动和室壁增厚度异常分别有250个、240个和276个节段.局部灌注异常的节段与局部射血分数、局部室壁活动和室壁增厚度异常的节段不完全匹配.结论 ~(99)Tc~m-NOET静息门控心肌灌注显像对冠心病的诊断有较大临床应用价值,所获得的整体心室功能参数在心肌梗死的评价中有优越性,但对心肌缺血的诊断价值不大.心肌梗死中存在有不少的局部灌注与心肌室壁功能异常节段的不匹配,对心肌存活的评价有帮助.     

64层螺旋CT心脏检查对比剂注射方案的优化

目的：探讨64层螺旋CT心脏检查中应用三时相一次扫描获得理想的冠状动脉图像、心脏形态和功能分析的对比剂优化注射方案。方法：将326例患者以不同注射方案随机分成5组：方案A,30例,单期注射,仅团注80～90ml对比剂。方案B30例,双期注射,团注60～80ml对比剂后于第二时相注射30ml生理盐水。方案C、D、E共266例,均行三期注射。其中,方案C 92例;方案D 83例;方案E91例。第一时相团注50～60ml对比剂,第二时相分别以不同比率（方案C 50％,方案D 40％,方案E 30％）注射30～40ml对比剂-生理盐水混合液,第三时相注射30ml生理盐水。分别测量升主动脉根部、同层面胸主动脉、主肺动脉、左心室及右心室的CT值,计算心室腔-心室壁的对比噪声比（CNR）。比较不同对比剂注射方案冠状动脉各级分支显示情况及右心室内对比剂均匀性。结果：CNR左心室各组间差异无统计学意义（P〉0．05）;CNR右心室各组间有显著性差异（P〈0．01）,C组CNR右心室明显高于其他各组（P〈0．01）。左心室、升主动脉根部和降主动脉的平均CT值差异无统计学意义（P〉0．05）;主肺动脉和右心室的平均CT值有显著性差异（P〈0．01）,其中,右心室CT值C组高于其他各组（P〈0．01）。各组在冠状动脉的显示方面无统计学意义（P〉0．05）。右心室的均匀性各组间存在显著性差异（P〈0．01）,C组优于A、B、D组（P〈0．05）,与E组间差别无明显统计学意义（P〉0．05）。结论：应用三时相注射方案,先团注50～60ml对比剂（第一时相）,再以50％的比率注射30～40ml对比剂-生理盐水混合液（第二时相）,随后注射30ml生理盐水（第三时相）,一次扫描不仅可以在清晰显示冠状动脉的同时行心脏形态和功能分析,而且减少了对比剂的用量,可以为临床冠心病的筛查提供相应的综合?     

Non-invasive assessment of coronary artery stent patency with multislice CT: preliminary experience

PURPOSE: To evaluate the diagnostic accuracy of multislice computed tomography coronary angiography (MSCT-CA) in the detection of in-stent restenosis. MATERIALS AND METHODS: Forty-two patients (33 male, 9 female, mean age 58+/-8 years) previously subjected to percutaneous implantation of coronary stent with suspected in-stent restenosis, underwent a 16-row MSCT (Sensation 16, Siemens) examination. The average time between stent implantation and MSCT-CA was 7.4+/-5.3 months. The following scan parameters were used: collimation 16x0.75 mm, rotation time 0.42 s, feed 3.0 mm/rot., kV 120, mAs 500. After administration of iodinated contrast material (Iomeprol 400 mgI/ml, 100 ml at 4 ml/s) and bolus chaser (40 ml of saline at 4 ml/s) the scan was completed in <20 s. All segments with a stent were assessed by two observers in consensus and were graded according to the following scheme: patent stent, in-stent intimal hyperplasia (IIH) (lumen reduction <50%), in-stent restenosis (ISR) (=/>50%), in-stent occlusion (ISO) (100%). Consensus reading was compared with coronary angiography. RESULTS: Forty-seven stents were assessed (16 in the right coronary artery; 4 in the left main; 22 in the left anterior descending; 5 in the circumflex). In 7 (17%) stents there was ISR (3) or ISO (4), and in 4 (10%) stents there was IIH. The sensitivity and negative predictive values for the detection of ISO were 80% and 98%, respectively, while for the detection of ISR+ISO they were 50% and 89%, respectively. CONCLUSIONS: Although the results are encouraging, the follow-up of stent patency with MSCT-CA does not show a diagnostic accuracy suitable for clinical implementation.     

前瞻性心电门控多期相重建在儿童冠状动脉CT检查中的应用

目的:探讨前瞻性心电门控多期相重建技术在儿童冠状动脉CT成像中的应用。方法:回顾性选取2017年6月-2018年5月在本院行冠状动脉CTA检查且心率为100~120次/分的60例患儿作为对照组,采用回顾性心电门控多相位扫描技术,重建40%、45%、50%、70%、75%和80%R-R间期的6组图像,选取其中冠状动脉成像质量主观评分最高的期相。前瞻性选取2018年6月-2019年5月在本院行冠状动脉CTA检查且心率为100~120次/分的60例2~4岁患儿作为实验组,采用前瞻性心电门控多期相重建技术,重建40%、45%和50%R-R间期的三组图像,选取其中冠状动脉成像质量主观评分最高的期相。两组患儿采用相同的扫描参数、对比剂用量和注射方式。对比两组中CT扫描的辐射剂量和冠状动脉血管成像质量。结果:实验组中冠状动脉40%、45%和50%R-R间期重建图像的主观评分分别为4.02±0.70、4.88±0.33和4.07±0.73,对照组中冠状动脉40%~80%R-R间期重建图像的主观评分依次为2.33±1.50、4.90±0.52、2.30±1.38、2.30±1.38、1.30±0.62和1.18±0.47;两组中最佳期相均为45%R-R间期,这2个期相的冠状动脉重建图像的主观评分之间的差异无统计学意义(P>0.05)。CTA扫描的有效辐射剂量,实验组为(0.42±0.07)mGy,对照组为(2.87±0.48)mGy,实验组较对照组降低85%,差异有统计学意义(P<0.05)。两组中对比剂用量,实验组为(19.24±5.12)mL,对照组为(18.75±4.26)mL,差异无统计学意义(P>0.05)。结论:前瞻性心电门控多期相重建技术可应用于儿童冠状动脉CT成像,在不影响冠状动脉成像质量的条件下,可显著降低患儿接受的辐射剂量。     

Use of saline chaser in the intravenous administration of contrast material in non-invasive coronary angiography with 16-row multislice Computed Tomography

PURPOSE: To investigate the impact of saline bolus chaser in coronary angiography with a 16-row multislice CT (16-MSCT) scanner. MATERIALS AND METHODS: 32 patients were divided in two groups for contrast material (cm) administration: group 1 (140 ml at 4 ml/s), and group 2 (100 ml at 4 ml/s followed by 40 ml of saline chaser at 4 ml/s). All patients underwent ECG-gated coronary angiography with a 16-MSCT scanner. The attenuation at the origin coronary vessels was assessed. Three regions of interest were drawn throughout the data-set: ascending aorta (ROI1); descending aorta (ROI2); pulmonary artery (ROI3). The attenuation in the superior vena cava was recorded (ROI4). The average attenuation and the slope were calculated in each ROI. RESULTS: The average attenuation in the coronary vessels was not significantly different in the two groups. The attenuation value in the superior vena cava was significantly inferior in group 2. CONCLUSIONS: 16-row MSCT coronary angiography with bolus chaser allows optimal vessel enhancement with a lower dose of cm and a lower enhancement of the superior vena cava and the right heart.     

Non-invasive 16-row multislice CT coronary angiography: usefulness of saline chaser

The aim of this study was to investigate the usefulness of saline chaser in 16-row multislice CT (16-MSCT) coronary angiography. Forty-two patients were divided into two groups for contrast material (CM) administration: group 1 (140 ml at 4 ml/s) and group 2 (100 ml at 4 ml/s followed by 40 ml of saline chaser at 4 ml/s). All patients underwent retrospectively ECG-gated 16-MSCT coronary angiography. The attenuation at the origin coronary vessels was assessed. Three regions of interest (ROIs) were drawn throughout the data set: (a) ascending aorta (ROI 1); (b) descending aorta (ROI 2); and (c) pulmonary artery (ROI 3). The attenuation in the superior vena cava was recorded (ROI 4). The average attenuation and the slope were calculated in each ROI and differences were assessed with a Students t test. The average attenuation in the coronary vessels was not significantly different in the two groups. The average attenuations in ROI 1 were 325 and 327 HU, in ROI 2 were 328 and 329 HU and in ROI 3 were 357 and 320 HU, for groups 1 and 2, respectively (p>0.05). The slopes in ROI 1 were –0.2 and 1.1, in ROI 2 were 2.8 and 2.1 (p>0.05) and in ROI3 were 3.9 and –9.0 (p<0.05), for groups 1 and 2, respectively. The average attenuations in ROI 4 were 927 and 643 HU (p<0.05), for groups 1 and 2, respectively. One hundred milliliters of CM with 40 ml of saline chaser provides the same attenuation as 140 ml of CM (35% less) with decreased hyper-attenuation in the superior vena cava.     

Diagnostic accuracy of 16-row multislice CT angiography in the evaluation of coronary segments

PURPOSE: To evaluate the diagnostic accuracy of 16-row multislice spiral computed tomography coronary angiography (16-MSCT-CA) for the non-invasive assessment of significant coronary artery stenosis. MATERIALS AND METHODS: We enrolled 40 patients (36 male, aged 59+/-11 yrs) with suspected obstructive coronary artery disease and a heart rate <65 bpm during the scan. The 16-MSCT-CA (Sensation 16, Siemens, Forchheim, Germany) was performed with electrocardiographically-gated technique after the intravenous administration of 100 ml of iodinated contrast material followed by a saline bolus chaser. The scan parameters were: collimation 16 x 0.75 mm, rotation time 0.42 s, feed/rot. 3 mm (pitch 0.25), 120 kVp, 500 mAs. All coronary segments = or >2 mm in diameter were evaluated by two independent observers for the presence of significant coronary artery stenosis (= or >50%). Consensus reading was compared to quantitative coronary angiography. RESULTS: The average heart rate was 55+/-6 bpm. Of the 428 segments of = or >2.0 mm diameter 92 were significantly diseased. Without exclusion of any branches (428), the sensitivity, specificity, positive, and negative predictive values to identify = or >50% obstructed segments were 95.7% (88/92), 95.8% (322/336), 86.3% (88/102), and 98.8% (322/326), respectively. No occluded left main, left anterior descending, circumflex or right coronary artery segments remained undetected. CONCLUSIONS: 16-MSCT-CA in a selected low-heart-rate patient population provides high diagnostic accuracy in the evaluation of significant coronary artery stenosis.     

16-MDCT coronary angiography versus invasive coronary angiography in acute chest pain syndrome: a blinded prospective study

OBJECTIVE: The purpose of our study was to prospectively evaluate the usefulness of CT coronary angiography versus invasive coronary angiography for the detection of clinically significant coronary artery disease in patients hospitalized for acute chest pain syndrome. SUBJECTS AND METHODS: Sixty-six consecutive patients (52 men and 14 women; average age, 57 +/- 11 [SD] years) who were hospitalized for acute chest pain syndrome underwent CT coronary angiography and invasive coronary angiography within an average time interval of 4 days. ECG-gated CT coronary angiography was performed with a 16-MDCT scanner (0.42-sec rotation time, 16 x 0.75 mm detector collimation). Beta-blockers were not administered routinely, and thus the average heart rate was 71 +/- 11 beats per minute. CT coronary angiographic images were evaluated concurrently by two radiologists, who were blinded to invasive coronary angiography results, for stenoses having a diameter of 50% or more, using a 15-segment classification, including all segments 2 mm or more in diameter. The consensus interpretation was compared with results of invasive coronary angiography. RESULTS: CT coronary angiography was technically successful in 59 patients (89%). After exclusion of 20 (3.1%) of 649 coronary segments, which were classified as nonevaluable by CT coronary angiography, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CT coronary angiography for identifying significant coronary artery disease in the remaining 629 coronary segments were 80% (68/85), 89% (482/544), 52% (68/130), 97% (482/499), and 87% (550/629), respectively. The overall accuracy for the main vessels (left main, left anterior descending, left circumflex, and right coronary arteries) was 93%, 88%, 86%, and 86%, respectively. CONCLUSION: CT coronary angiography using a 16-MDCT scanner enables accurate noninvasive detection of significant coronary artery disease in patients hospitalized for acute chest pain syndrome. Furthermore, relative high sensitivity and specificity of CT coronary angiography can be achieved without pharmacologic manipulation of patient heart rates.     

Diagnostic accuracy of 64-slice CT in the assessment of coronary stents

PURPOSE: The purpose of this study was to assess the diagnostic accuracy of 64-slice computed tomography (64-CT) coronary angiography in the detection of coronary in-stent restenosis. MATERIALS AND METHODS: Ninety-five patients (72 men and 23 women, mean age 58+/-8 years) with previous percutaneous coronary intervention with stenting and suspected restenosis underwent 64-CT (Sensation 64, Siemens). The mean time between stent deployment and 64-CT was 6.1+/-4.2 months. The scan parameters were: slices 32 x 2, individual detector width 0.6 mm, rotation time 0.33 s, feed 3.84 mm/rotation, 120 kV, 900 mAs. After the intravenous administration of iodinated contrast material (Iomeprol 400 mgI/ml, Iomeron, Bracco) and a bolus chaser (40 ml of saline), the scan was completed in <12 s. All coronary segments with a stent were assessed on 64-CT by two observers in consensus and judged as: patent, with intimal hyperplasia (lumen reduction of <50%), with in-stent restenosis (> or =50%), or with in-stent occlusion (100%). The consensus reading was compared with conventional coronary angiography. RESULTS: Four patients were excluded because of insufficient image quality. In the remaining 91, we assessed 102 stents (31 RCA; 10 LM; 54 LAD; 7 CX). In 14 (13.7%) stents, in-stent restenosis (n=8) or in-stent occlusion (n=6) was found. Intimal hyperplasia was detected in 11 (10.8%) stents. The sensitivity and negative predictive value of 64-CT for in-stent occlusion were 100% and 100%, respectively, whereas for all stenoses, >50% they were 92.9% and 98.7%, respectively. CONCLUSIONS: We found that 64-CT has a high diagnostic accuracy for the detection of in-stent restenosis in a selected patient population.     

Comparison of monophasic vs biphasic administration of contrast material in non-invasive coronary angiography using a 16-row multislice Computed Tomography

PURPOSE: To compare two different techniques for the administration of the bolus of contrast material (cm) in coronary angiography with multislice CT (MSCT) scanner. MATERIALS AND METHODS: Thirty consecutive patients were divided into two groups. In group 1 contrast material was administered with the monophasic protocol (140 ml of cm at 4 ml/s). In group 2 contrast material was administered with the biphasic protocol (70 ml of cm at 4 ml/s and 70 ml at 3 ml/s). The angiographic scan was performed in both groups with a 16-row MSCT scanner. Three regions of interest were drawn in each scan throughout the data-set in order to measure attenuation: 1) ascending aorta (ROI1); 2) descending aorta (ROI2); 3) pulmonary artery (ROI3). Attenuation was also assessed at the origin of the main coronary arteries. RESULTS: No significant differences of the attenuation values were observed at the origin of the coronary arteries (p>0.05). The attenuation profile of the monophasic protocol showed higher and longer attenuation values than the biphasic protocol. CONCLUSIONS. The biphasic administration of contrast material does not supply significant advantages on the enhancement of the great vessels and the coronary arteries in 16-row MSCT coronary angiography.