Prospective respiratory-triggered 64-slice CT pulmonary angiography for detection of pulmonary embolism—a feasibility study in a porcine model

The objective of this study is to investigate the feasibility of prospectively respiratory-triggered CT pulmonary angiography (CTPA) for detection of pulmonary embolism (PE) in a porcine model. A free-breathing respiratory-triggered multislice CTPA (120 kV, 140 mAs_eff, 2.5-mm slice thickness) and two CTPA in breath-hold technique (120 kV, 140 mAs_eff. and 250mAs_eff, 1-mm and 3-mm image reconstruction) were performed in six pigs with pulmonary embolism. Diagnostic accuracy was computed, and differences in detection rates between both techniques were assessed on a per-embolus basis with the Wilcoxon test. Thin-sliced 1-mm images, acquired with 250mAs_eff, served as the standard of reference. Respiratory-triggered CTPA reached high diagnostic accuracy in detection of lobar and segmental PE equal to the results with the breath-hold technique (p > 0.05). For detection of subsegmental emboli, standard breath-hold techniques performed significantly better than respiratory-gated CTPA (sensitivity, 68.3% versus 24.4%; p < 0.05). Free-breathing respiratory-triggered CTPA is feasible for detection of lobar and segmental PE, with diagnostic accuracy equivalent to that of a standard CTPA in breath-hold. Although this technique is not recommended for assessment of emboli in the subsegmental vasculature, prospective respiratory-triggered CTPA may be of added value in patients who cannot hold their breath appropriately for CTPA scanning.     

64层螺旋CT血管成像在肺动脉栓塞中的诊断价值

目的:探讨64层螺旋CT血管成像在诊断肺动脉栓塞中的价值。方法:回顾性分析19例临床确诊为肺动脉栓塞的64层螺旋CT肺动脉成像资料,并用最大密度投影(MIP)、多平面重组(MPR)、容积再现(VR)等方法显示肺动脉。结果:19例患者中,其中左右肺动脉栓塞有8支,叶肺动脉栓塞27支,段及亚段肺动脉栓塞56支。偏心型41支,闭塞型38支,中央型8支,附壁环形型4支。结论:64层螺旋CT肺动脉成像可作为肺动脉栓塞诊断的首选方法。     

64层螺旋CT血管造影对肺动脉栓塞的临床诊断价值

目的探讨64层螺旋CT血管造影对肺动脉栓塞的临床诊断价值。方法 30例患者行肺动脉CTA检查,并采用多平面重建（MPR）对原始数据进行后处理。结果 30例均能显示肺栓塞的部位、范围及局部管腔狭窄程度,CT表现为肺动脉内不规则斑块状、附壁样缺损,周围有或无高密度对比剂包绕。结论 64层螺旋CT血管造影是临床诊断肺动脉栓塞最有效的无创性方法之一。     

64层螺旋CT肺血管造影在肺栓塞诊疗中的应用价值

目的 探讨64层螺旋CT在肺栓塞诊断及治疗中的指导作用。方法 63例患者均行64层螺旋CT肺血管造影(CTPA),并进行多种形式的图像重建结合轴位图像分析。结果 64层螺旋CTPA对63例患者肺动脉各级管腔内的栓子均明确显示,共累及肺动脉303支;图像分析结果伞部显示肺栓塞的直接征象为:主肺动脉和(或)左右肺叶、段、亚段血管腔内充盈缺损和血管阻塞;部分显示肺栓塞的间接征象为:马赛克征、右心房及右心室肥厚及扩张、肺动脉扩张、胸腔积液、肺不张及实变(肺梗死)等。62例患者经溶栓治疗后复查CTPA,其中,栓子完全消失者47例,栓子明显缩小者11例,溶栓治疗效果差者3例,考虑为慢性肺栓塞。结论 64层螺旋CTPA是临床最有效的诊断肺栓塞及溶栓后疗效评价的无创性方法之一。     

64层螺旋CT肺血管造影在肺栓塞诊疗中的应用价值

目的 探讨64层螺旋CT在肺栓塞诊断及治疗中的指导作用.方法 63例患者均行64层螺旋CT肺血管造影(CTPA),并进行多种形式的图像重建结合轴位图像分析.结果 64层螺旋CTPA对63例患者肺动脉各级管腔内的栓子均明确显示,共累及肺动脉303支;图像分析结果伞部显示肺栓塞的直接征象为:主肺动脉和(或)左右肺叶、段、亚段血管腔内充盈缺损和血管阻塞;部分显示肺栓塞的间接征象为:马赛克征、右心房及右心室肥厚及扩张、肺动脉扩张、胸腔积液、肺不张及实变(肺梗死)等.62例患者经溶栓治疗后复查CTPA,其中,栓子完全消失者47例,栓子明显缩小者11例,溶栓治疗效果差者3例,考虑为慢性肺栓塞.结论 64层螺旋CTPA是临床最有效的诊断肺栓塞及溶栓后疗效评价的无创性方法之一.     

64层螺旋CT肺动脉造影在诊断肺栓塞中的应用

<正>肺动脉栓塞(pulmonary embolism,PE),简称肺栓塞,是由于内源性或外源性栓子堵塞肺动脉,引起肺循环障碍的临床和病理生理综合征,其中发生肺出血或坏死者称为肺梗死。栓子包括内源性栓子和外源性栓子,如血栓栓子、脂肪栓子、羊水栓子及     

64层螺旋CT肺动脉造影在肺动脉栓塞诊断中的应用

目的 探讨64层螺旋CT肺动脉造影(CT pulmonary angiography,CTPA)对肺动脉栓塞(pulmonary embolism,PE)的诊断价值.方法 回顾分析24例肺动脉栓塞患者的64层螺旋CT增强图像,将原始图像复制到EBW4.0工作站,对肺动脉主干及分支进行多平面重建(MPR),最大密度投影(MIP)及容积重建(VR)分析.结果 24例患者中,共检出了76处肺动脉及其分支的栓子.其中,左、右肺动脉主干14处(右主干10处、左主干4处),肺叶动脉24处,肺段动脉26处,亚肺段动脉12处.CT表现为肺动脉主干或分支内混合性、附壁性、中心性充盈缺损,可分为完全性或部分性.结论 64层CTPA具有准确、高效、无创等优点,可直观、立体地观察到肺动脉血栓的大小、分布、范围及类型,是临床诊断及观察疗效的首选方法,有望成为肺动脉栓塞检查的“金标准”.     

64层CT血管成像与肺通气灌注显像诊断肺栓塞的对比研究

目的:通过比较两种无创影像检查为临床诊断肺栓塞提供有指导意义检查方法。方法:64层螺旋CT肺动脉成像和肺通气/灌注显像图像依据相同的诊断标准进行独立的分析。V/Q显像和多层螺旋CT肺动脉成像两种检查方法的判定结果进行相关分析,两者准确性、符合性及不确定性诊断比率的差异采用2检验进行比较。结果:180例患者中CTPA和V/Q显像诊断PE的敏感性、特异性、符合率分别为90.5%对83.8%,91.5%对85.0%,91.1%对84.4%。CTPA和V/Q显像诊断PE的κ值分别为0.680,0.648。结论:疑诊肺栓塞病例中两者皆可作为确诊及排除疑诊肺栓塞病例的检查方法。     

64层CT肺动脉造影对肺栓塞诊断及治疗后复查的应用研究

目的:探讨64层CT肺动脉造影(CTPA)对肺栓塞的诊断效果及治疗后复查的价值。方法:对32例肺动脉栓塞的患者采用64层CT行CTPA检查,并进行多平面重建(MPR)、最大密度投影及容积重建处理。患者复查采用相同CT检查及后处理重建。结果:32例患者中15例有下肢静脉栓塞、4例有恶性肿瘤、3例有近期手术病史,2例有近期外伤史。CTPA对肺动脉主干、左右肺动脉及叶、段、亚段动脉显示良好,32例患者中显示受累肺动脉221支,其直接征象为肺动脉血管内充盈缺损,间接征象包括肺梗死实变、肺野少血征、胸腔积液等。肺栓塞治疗后复查有24例患者1月内肺动脉栓子消失或明显吸收缩小(占75%);6例患者吸收不明显(占18.7%);2例死亡。结论:64层CT能清楚地显示肺栓塞的形态、部位及其它间接征象,并能有效监测治疗效果,为临床提供有益帮助。     

16排螺旋CT血管造影在肺动脉栓塞诊断中的应用

目的探讨16排螺旋CT血管造影（MSCTA）在肺动脉栓塞（PE）诊断中的临床应用价值。方法8例临床疑诊PE患者行MSCTA检查,并将薄层数据行多平面重组（MPR）与容积重建（VR）。结果CT诊断PE8例,共35处肺动脉栓子,其中,段及段以上栓子26处,亚段及以下栓子9处。栓子显示为部分性充盈缺损,附壁性充盈缺损,中心性充盈缺损以及完全性充盈缺损。结论MSCTA能直观地显示肺动脉各级栓子的部位和形态,对临床治疗方案的选择及疗效评价有较高的应用价值。     

64-Slice multidetector row CT angiography of the abdomen: comparison of low versus high concentration iodinated contrast media in a porcine model

Objective

In this study we aimed to assess the image quality and degree of vascular enhancement using low-concentration contrast media (LCCM) (300 mg I ml^–1) and high-concentration contrast media (HCCM) (370 mg I ml^–1) on 64-slice multidetector row CT (MDCT) abdominal CT angiography (CTA). In addition, we aimed to study the feasibility of using HCCM with a reduced total iodine dose.

Methods

CTA of the abdomen on a 64-slice MDCT was performed on 15 anaesthetised pigs. Study pigs were divided into three groups of five each based on the iodine concentration and dose received: Group A (LCCM; 300 mg I ml^–1), Group B (HCCM; 370 mg I ml^–1) and Group C HCCM with 20% less iodine dose. The total iodine injected was kept constant (600 mg kg^–1) in Groups A and B. Qualitative and quantitative analyses were performed to study and compare each group for image quality, visibility of the branch order of the superior mesenteric artery (SMA), artefacts, degree of enhancement in the aorta and main stem arteries and uniformity of enhancement in the aorta. Groups were compared using the analysis of variance test.

Results

The image quality of 64-slice MDCT angiography was excellent with a mean score of 4.63 and confident visualisation of the third to fifth order branches of the SMA in all groups. Group B demonstrated superior vascular enhancement, as compared with Groups A and C (p≤0.05). Uniform aortic enhancement was achieved with the use of LCCM and HCCM with 20% less iodine dose.

Conclusion

64-slice MDCT angiography of the abdomen was of excellent quality. HCCM improves contrast enhancement and overall CTA image quality and allows the iodine dose to be reduced.CT angiography (CTA) has rapidly emerged as a non-invasive imaging modality of choice to evaluate vasculature and vascular conditions in the abdomen [1-4]. Multidetector row CT (MDCT) has played a crucial role in the widespread acceptance of CTA as a non-invasive alternative to catheter angiography. Technical advances with the addition of more detector rows have significantly improved the spatial resolution and scanning speed of MDCT. CTA is evolving to adapt to these changes in MDCT technology. A marked reduction in scan duration with the newer 64-slice MDCT requires optimisation of scan timing to catch the bolus of enhancement for vascular and multiphasic organ imaging. Therefore, contrast administration strategies and scanning protocols need to be optimised either by increasing the rate of contrast injection or through the use of contrast media (CM) with a higher iodine concentration to adapt to a shorter scan duration. Increasing the rate of CM injection is limited, as it requires a relatively large-bore intravenous cannula for injection and could potentially increase the risk of extravasation [5]. By contrast, increasing the iodine concentration in CM not only improves contrast enhancement by increasing iodine flux, but could also help to reduce the volume of CM; the use of reduced volumes is highly desirable to match the shorter acquisition times on 16-slice and higher MDCT [6]. Use of high-concentration CM (HCCM) has been shown to provide superior vascular enhancement as compared with low-concentration CM (LCCM) on either 4- or 16-slice MDCT [7-11].In this study, we assessed the performance of abdominal CTA on 64-slice MDCT and compared the degree of enhancement and image quality using LCCM (300 mg I ml^–1) with HCCM (370 mg I ml^–1) in a porcine model. In addition, the potential of reducing the contrast volume or total iodine dose with the use of HCCM for CTA was assessed and compared with a regular dose of LCCM and HCCM.     

64-slice multidetector coronary CT angiography: in vitro evaluation of 68 different stents

The purpose of this study was to test a large sample of different coronary artery stents using four image reconstruction approaches with respect to lumen visualization, lumen attenuation, and image noise in 64-slice multidetector-row computed tomography (MDCT) in vitro and to provide a catalogue of currently used coronary artery stents when imaged with state-of the-art MDCT. We examined 68 different coronary artery stents (57 stainless steel, four cobalt-chromium, one cobalt-alloy, two nitinol, four tantalum) in a coronary artery phantom (vessel diameter 3 mm, intravascular attenuation 250 HU, extravascular density −70). Stents were imaged in axial orientation with standard parameters: 32x0.6 collimation, pitch 0.24, 680 mAs, 120 kV, rotation time 0.37 s. Four different image reconstructions were obtained with varying convolution kernels and section thicknesses: (1) soft, 0.6 mm, (2) soft, 0.75, (3) medium soft, 0.6, and (4) stent-optimized sharp, 0.6. To evaluate visualization characteristics of of the stent, the lumen diameter, intraluminal density and noise were measured. The high-resolution kernel offered significantly better average lumen visualization (57% ±10%) and more realistic lumen attenuation (222 HU ±66 HU) at the expense of increased noise (15.3 HU ±3.7 HU) compared with the soft and medium-soft CT angiography (CTA) protocol (p<0.001 for all). Stents with a lumen visibility of more than 66% were: Arthos pico, Driver, Flex, Nexus2, S7, Tenax complete, Vision (all 67%), Symbiot, Teneo (70%), and Radius (73%). Only ten stents showed a lumen visibility of less than 50%. Stent lumen visibility largely varies depending on the stent type. Even with the improved spatial resolution of 64-slice CT, a stent-optimized kernel remains beneficial for stent visualization when compared with the standard medium-soft CTA protocol. Using 64-slice CT and high-resolution kernel, the majority of stent products show a lumen visibility of more than 50% of the stent diameter.     

64排VCT增强扫描在肺动脉栓塞中的诊断价值

目的:探讨64排容积CT(VCT)增强扫描在肺动脉栓塞诊断中的价值。方法:搜集17例经64排VCT增强扫描确诊的肺动脉栓塞患者的影像资料,所有病例均行多平面重组(MPR)、曲面重组(CPR)、三维容积成像(VRT)及最大密度投影(MIP)等后处理,对血栓的形态、部位、表现形式以及其它相关改变进行归类分析。结果:17例共累及肺动脉及其分支87处,其CT表现直接征象:中心性充盈缺损(轨道征)9处、偏心性或附壁性充盈缺损26处、完全阻塞性充盈缺损(血管截断征)13处;间接征象:肺动脉增宽7例、局限性肺纹理稀疏和肺灌注不均(马塞克征)14例、肺梗死6例、胸腔积液6例、心包积液4例。结论:64排VCT增强扫描是一种安全、快捷、有效的诊断肺栓塞的无创性检查手段,其检出率高,可作为肺栓塞的首选检查方法。     

64-detector volume CT angiography in diagnosis of pulmonary embolism

目的:探讨64排容积CT(VCT)增强扫描在肺动脉栓塞诊断中的价值.方法:搜集17例经64排VCT增强扫描确诊的肺动脉栓塞患者的影像资料,所有病例均行多平面重组(MPR)、曲面重组(CPR)、三维容积成像(VRT)及最大密度投影(MIP)等后处理,对血栓的形态、部位、表现形式以及其它相关改变进行归类分析.结果:17例共累及肺动脉及其分支87处,其CT表现直接征象:中心性充盈缺损(轨道征)9处、偏心性或附壁性充盈缺损26处、完全阻塞性充盈缺损(血管截断征)13处;间接征象:肺动脉增宽7例、局限性肺纹理稀疏和肺灌注不均(马塞克征)14例、肺梗死6例、胸腔积液6例、心包积液4例.结论:64排VCT增强扫描是一种安全、快捷、有效的诊断肺栓塞的无创性检查手段,其检出率高,可作为肺栓塞的首选检查方法.     

16层螺旋CT肺动脉造影对肺栓塞诊断的临床价值

目的:探讨16层螺旋CT肺血管造影术(MSCTPA)诊断肺动脉栓塞的临床价值。方法:对临床拟诊肺栓塞的46例患者行MSCTPA检查及后重建技术,后重建方法包括容积再现(VR)、多平面重建(MPR)、最大密度投影(MIP)。结果:46例共发现栓子698个,其中肺动脉主干4个,左右肺动脉41个,叶动脉114个,段及亚段动脉539个。直接征象:①)血管截断征,表现为肺动脉管腔完全闭塞;②轨道征,表现为腔内充盈缺损位于血管中央,周围有对比剂环绕;③偏心性充盈缺损,表现为管腔内不规则充盈缺损偏向管壁一侧,边缘欠光整;④附壁性充盈缺损。间接征象:①肺窗观察见局限性的血管纹理稀疏,呈"马赛克征";②肺梗死,表现为肺外围以胸膜为基底的楔形或条状实变影;③胸腔积液、肺动脉高压、右心室肥大以及心包积液等。结论:MSCTPA能对肺动脉栓塞作出准确诊断,是无创、快速、安全、敏感的检查方法,并可追踪复查,评估治疗效果。     

64层螺旋CT血管成像技术对肺动静脉瘘的诊断价值

目的 探讨64层螺旋CT血管成像技术对肺动静脉瘘的诊断价值。方法 对12例临床怀疑肺动静脉瘘的患者行CT血管成像检查。对所有扫描图像行容积再现（VR）、最大密度投影（MIP）以及冠状多平面重组（MPR）。结果 12例患者均确诊为肺动静脉瘘，7例为单发，5例为多发，共发现20处肺动静脉瘘，除漏诊1例合并位于近心位置的3处肺动静脉直接交通外，其余病变均诊断正确且无遗漏。结论 64层螺旋CT血管成像技术可以无创地诊断肺动静脉瘘，为治疗方案的制定及术后随访提供依据。     

肺栓塞患者64层螺旋CT检查的精心护理

目的确定精心护理在肺动脉栓塞患者接受64层螺旋CT检查或复查中的临床意义。方法2005年12月至2009年1月在我院临床确诊或疑诊肺动脉栓塞85例患者（分别为40例和45例）于64层螺旋CT检杏或复查（包括肺动脉造影和深静脉造影）前后，均得到精心护理。结果造影术前与术中的护理保证了本组患者中肺动脉造影和深静脉造影的成功进行，而术后护理有效地预防和控制了源自上述检查的并发症。结论精心护理在肺动脉栓塞患者的CT检查中，始终起着保驾护航作用。     

16层螺旋CT血管造影在肺动脉栓塞诊断中的价值

肺动脉栓塞(pulmonary embolism,PE)是内源性或外源性栓子阻塞肺动脉及其分支引起的肺循环障碍的临床病理生理综合征,并发肺出血或坏死者称为肺梗死[1]。PE是一种常见的心血管疾病,它具有发病率高,临床表现缺乏特异性,易漏诊及误诊,未经治疗者死亡率高的特点,达20%~30%,及时诊断治疗者死亡率可降至2%~8%[2]。近年来,尤其是多层螺旋CT血管造影(MSCTA)等先进技术的应用使PE的及时诊断成为可能,本文报告23例PE的MSCTPA表现如下。1材料与方法1.1临床材料本组23例中,男14例,女9例,年龄14~82岁,平均61岁。其中10例有下肢深静脉血栓,4例有…     

Pulmonary embolism: comparison of gadolinium-enhanced MR angiography with contrast-enhanced spiral CT in a porcine model

RATIONALE AND OBJECTIVES: The purpose of this study was to compare gadolinium-enhanced magnetic resonance (MR) angiography with contrast material-enhanced computed tomography (CT) for the detection of small (4-5-mm) pulmonary emboli (PE), with a methacrylate cast of the porcine pulmonary vasculature used as the diagnostic standard. MATERIALS AND METHODS: In 15 anesthetized juvenile pigs, colored methacrylate beads (5.2 and 3.8 mm diameter-the size of segmental and subsegmental emboli in humans) were injected via the left external jugular vein. After embolization, MR angiographic and CT images were obtained. The pigs were killed, and the pulmonary arterial tree was cast in clear methacrylate, allowing direct visualization of emboli. Three readers reviewed CT and MR angiographic images independently and in random order. RESULTS: Forty-nine separate embolic sites were included in the statistical analysis. The mean sensitivity (and 95% confidence intervals) for CT and MR angiography, respectively, were 76% (68%-82%) and 82% (75%-88%) (P > .05); the mean positive predictive values, 92% (85%-96%) and 94% (88%-97%) (P > .05). In this porcine model, PE were usually seen as parenchymal perfusion defects (98%) with MR angiography and as occlusive emboli (100%) with CT. CONCLUSION: MR angiography is as sensitive as CT for the detection of small PE in a porcine model.