多层螺旋CT评价冠状动脉疾病的进展

1998 年推出的 4 层螺旋 CT是 CT发展史上的又一次革命,其时间与空间分辨力的极大提高,在与单层CT相同的时间内可进行更大范围的薄层扫描,同时也使冠状动脉的 CT成像成为可能。2000年推出的8层CT及2002年推出的16层CT,尤其是后者较4层CT进一步提高了时间分辨力(210 ms)和空     

冠状动脉狭窄的多层螺旋CT诊断

目的 旨在评价多层螺旋CT（MDCT）诊断冠状动脉（简称冠脉）狭窄的可行性和准确性。方法 65名患者行冠脉MDCT造影（MDCTA），扫描数据在回顾性心电门控下重建。有32例同时接受选择性冠脉造影（SCA）。分析CT图像质量，并与SCA比较，评价MDCTA诊断50％以上狭窄的准确性。结果 心率70次／min以下患者CT图像质量明显优于心率70次／min以上组（W＝539，P＜0．0001）。32例MDCTA图像与相应SCA比较，MDCTA诊断50％以上狭窄的敏感度、特异率、阴性预测值和准确度分别为95％、80％、89％和90％。结论 MDCT对冠脉能够高质量成像并可较准确诊断冠脉狭窄。     

多层螺旋CT冠状动脉成像的临床应用和进展

临床应用证明多层螺旋CT(MSCT)在心脏成像方面是切实有效的.综述了MSCT冠状动脉造影的检查技术和临床应用进展.MSCT冠状动脉造影可以部分取代导管法冠状动脉造影并作为冠心病诊断和治疗效果随访观察的重要手段.     

多层螺旋CT在肝脏的应用进展

多层螺旋CT具有扫描速度快，可采用较薄的层厚，扫描范围大，同时有较好的纵向分辨力等优点，在肝脏血管解剖的显示及肿瘤的检测等方面发挥了较大的作用。     

多层螺旋CT血管成像技术临床应用进展

随着多层螺旋CT扫描及重组技术的进展，CT血管成像的应用范围也越来越广。对多层螺旋CT血管成像的技术优势、技术特点以及临床研究热点做一综述。     

多层螺旋CT（二）

(接 2 0 0 0年第 3期 194页 )⑥ＣＴ透视 :对确定层位进行连续扫描 ,每偏移 30～ 6 0°使用 36 0°数据重建一幅图像 ,每秒可重建 6～ 12幅图像 ,四层同时显示。用以动态观察介入过程 ,达到确切定位的目的。⑦计算机容积成像 (ｃｏｍｐｕｔｅｄｖｏｌｕｍｅｒａｄｉｏｇｒａｐｈｙ ,ＣＶＲ) :对于已有的断面图像 ,包括冠状、矢状位重组图像 ,选择一定厚度范围的层面重合显示 ,相当于常规Ｘ线的体层摄影效果 ,密度分辨率明显提高。⑧ＣＴ发展预测 :多层ＣＴ的开发目的 ,是增加Ｘ线利用率 ,提高检查速度 (时间 /覆盖范围 )。由于Ｘ线锥形放射…     

多层螺旋CT评估孤立性肺结节的临床进展

多层螺旋CT是目前检验孤立性肺结节最敏感的方法,它能显示肺结节的微细结构,消除或减少常规CT扫描的部分容积效应,从而提高对孤立性肺结节检测的准确性。本文重点综述多层螺旋CT扫描技术、孤立性肺结节形态学评估及其对孤立性肺结节的诊断价值、孤立性肺结节的CT增强扫描来探讨多层螺旋CT评估孤立性肺结节的临床进展。     

肺错构瘤的多层螺旋CT诊断

目的分析肺错构瘤的CT表现,并提高其诊断准确性。方法 31例由病理证实的肺错构瘤患者均经16层螺旋CT胸部平扫与增强扫描。对所有患者肿瘤病灶的部位、形态、大小、数目及强化特征,进行了回顾性总结分析。结果 CT扫描证实,25例(81%)的错构瘤是肺内型,其中包括24例孤立型和1例多发型,4例合并周围型肺癌。另外6例(19%)的错构瘤是支气管腔内型。绝大多数(30/31)患者的肿瘤CT表现是以边缘光滑锐利的圆形或卵圆形、直径小于3 cm的肿块影为特征。此外,还可看到其他或多或少的伴发征象,诸如,规则的圆形或卵圆形结节(58%),不规则形结节(48%),软组织密度结节影(55%),钙化影(35%),以及脂肪密度影(13%)。在对比增强CT像上,所有错构瘤病灶均表现为轻度强化(强化值小于30 HU)。结论除钙化及脂肪密度外,边界清晰及增强后轻度强化是诊断肺内型错构瘤的重要依据。而支气管腔内结节出现钙化或脂肪密度则高度提示支气管腔内型错构瘤。     

Tracheobronchomalacia: evolving role of dynamic multislice helical CT

Paired inspiratory and dynamic expiratory multislice CT imaging is a promising method for diagnosing TBM. A low-dose technique should be considered for the dynamic portion to reduce radiation exposure. Visual and quantitative analysis of the central airways provide a comprehensive assessment by allowing for the accurate diagnosis of TBM, determining its extent, assessing for predisposing conditions, and aiding selection of candidates for stent placement or tracheoplasty procedures. This technique can also be helpful for assessing response of airway dynamics following therapeutic intervention.     

多层螺旋CT肿瘤灌注成像的临床应用价值

目的 重点探讨多层螺旋CT（MSCT）的肿瘤灌注成像方法和临床应用价值.方法 对74例患者的全身不同各部位肿瘤行MSCT灌注成像,在常规CT平扫的基础上确定肿瘤中心部位后进行肿瘤灌注扫描,扫描图像经ADW4.2工作站处理,计算并分析灌注图像和灌注参数,包括血流量、血容量、平均通过时间、表面通透性以及肝脏肿瘤的肝动脉灌注指数.结果 74例患者的灌注成像中,除3例未能捕捉肿瘤中心的灌注图像外,其余71例肿瘤的灌注图像均清晰直观地显示肿瘤的大小和轮廓,并可定量检测肿瘤内部的组织灌注状态,听有肿瘤灌注参数明显变化,肺部肿瘤灌注成像受呼吸运动影响最大.结论 MSCT的肿瘤灌注成像是一种较为准确的定量分析肿瘤血流灌注状态的方法,具有重要的临床应用价值.     

Detection of coronary artery stenoses with multislice helical CT angiography

OBJECTIVES: The authors compared multislice CT angiography and selective angiography for the assessment of coronary artery disease. METHODS: In 28 patients, the presence and degree of coronary artery stenoses were determined in coronary segments prepared with beta-blocker for good image quality with multislice CT. RESULTS: In 187 coronary artery segments, sensitivity, specificity, and negative predictive value for the detection of stenoses >50% with multislice CT angiography were 81%, 90%, and 97%, respectively. The agreement for determining the degree of stenoses with multislice CT angiography and selective coronary angiography was only moderate (kappa = 0.58). CONCLUSIONS: Because of the limited spatial resolution, it is not possible with multislice CT angiography to determine the degree the coronary artery stenoses precisely. However, the high negative predictive value indicates that multislice CT may be a suitable tool to reliably rule out coronary artery disease.     

鼻骨低剂量螺旋CT扫描技术的应用

目的 探讨鼻骨低剂量多层螺旋CT扫描技术的应用价值.方法 将80例鼻骨正常的患者平均分为4组,保持球管电压120 kV不变,分别用常规剂量(125 mAs)和低剂量(75 mAs、50 mAs、25 mAs)进行扫描,扫描时分别记录辐射剂量值.由3名影像医师采用双盲法评价各剂量组的横断面图像及不同算法的重组图像的质量,结果用统计学方法处理.结果 各低剂量组的鼻骨轴位图像质量与常规剂量组相比无显著性差异(P>0.1);各组骨算法重组图像与软组织算法重组图像质量对比有显著性差异(P<0.01);25 mAs组长度剂量乘积(DLP)与常规剂量相比有显著性差异(P<0.01),容积剂量指数(CTDIvol)为常规剂量扫描的20.0%.结论 鼻骨低剂量CT扫描既能保证图像质量,又可大幅度降低病人的辐射剂量.采用软组织算法的VR图像优于骨算法VR图像.     

多层螺旋CT在肋间后动脉显示中的价值

目的评价多层螺旋CT(MSCT)对肋间后动脉显示的价值。方法回顾性分析26例胸部正常者的16层螺旋CT增强扫描图像,结合横断面及最大密度投影(MIP)、容积再现(VR)重组图像,测量观察各支肋间后动脉的起点及走行规律。结果肋间后动脉总显示率为93.38%(437/468支),左、右两侧显示率分别为92.31%(216/234支)和94.44%(221/234支)。77.31%(167/216支)左侧肋间后动脉起于胸主动脉后壁,右侧肋间后动脉起点分别位于胸主动脉后壁、右后壁和右壁,且自上而下渐由右壁向后壁移行。各肋间后动脉起点处内径自上而下略有增粗(0.162～0.208cm),左右两侧差异无统计学意义(P>0.05)。肋间后动脉进入肋沟处与棘突连线及同侧横突的平均垂直距离分别为(7.43±1.18)cm和(4.41±1.15)cm。结论应用MSCT增强扫描可以清晰显示肋间后动脉的起始及走行等解剖结构。     

多层螺旋CT在原发性输尿管癌中的应用

目的:探讨多层螺旋CT在原发性输尿管癌诊断中的价值。方法:搜集7例经手术病理证实的原发性输尿管癌的资料,分析其CT特点。结果:CT增强轴位扫描及MPR/CPR重建能够清楚地显示病变大小、形态、范围及其与周围组织地关系。结论:多层螺旋CT容积扫描及MPR/CPR重建能较好显示病变,使病变定位、定性诊断更加准确,为临床手术治疗提供帮助。     

Paddle-wheel multislice helical CT display of pulmonary vessels and other lung structures

The authors have now instituted the paddle-wheel method of CT reconstruction imaging of the lungs as a routine supplement to the standard axial multislice helical CT pulmonary angiography images for pulmonary embolism, and are exploring its role in other diseases. This unique way of viewing lung structures adds a new dimension to pulmonary imaging. Large-scale comparison studies of the traditional and the proposed paddle-wheel CT display method are necessary to quantitate their relative clinical effectiveness in the evaluation of the pulmonary vasculature, airways, and lungs.     

Primary radiation outside the imaged volume of a multislice helical CT scan

Multislice helical CT scanning has advantages of speed and X-ray tube loading, making it possible to image larger volumes in a single exposure. Our aim is to investigate dose implications for short scans from the additional X-ray tube rotations required to reconstruct a given volume in helical scanning. To this end a multislice scanner was compared with a single slice scanner. Two independent methods were used. The first was based on optical density measurements taken from a film exposed free-in-air as it moves with the CT bed along the scan axis. The second used measurements from a pencil ionization chamber supported free-in-air at the centre of the CT aperture for the duration of both a long scan and a short scan. This method assumes the same excess primary radiation at the extremes of both scans and the measurements are incorporated into two simultaneous equations. The dose-length product outside the imaged volume has been compared with the dose-length product inside the imaged volume using both methods. For 4 x 5 mm multislice collimation with a 360 degrees interpolation and a pitch of 0.875, the film and simultaneous equations methods show an excess dose-length product at the extremes of the scan volume equivalent to 3.3 cm and 3.5 cm extra scan length, respectively. This represents a large percentage of a short scan and is substantially greater than for a helical scan using the single slice scanner with 5 mm collimation, a 360 degrees interpolation and a pitch of 1. The latter showed an excess dose-length product at the extremes which was equivalent to 0.35 cm scan length by the film method and 0.25 cm using simultaneous equations. Taking the abdominal protocols recommended by the respective manufacturers, however, the multislice scanner could cover a 45 cm scan length in a single exposure, while the single slice scanner needed six exposures to image the same volume. With the multislice scanner set at 4 x 2.5 mm collimation, 360 degrees interpolation and a pitch of 0.875, the dose-length product outside the volume of interest was equivalent to 1.9 cm scan length by the first method and 1.8 cm using the second method. With 4 x 1 mm collimation it was equivalent to 1.0 cm using both methods. Changing the interpolation algorithm from 360 degrees to 180 degrees had no effect on the additional equivalent scan length while doubling the pitch resulted in a 25% increase. We conclude from this study that with the multislice scanner, the axial mode is to be preferred for short CT scans such as those used in patient biopsies and drainage. For paediatric helical scans shorter than 13 cm, dose length product is reduced by using 4 x 2.5 mm rather than 4 x 5 mm collimation. For longer scans, however, the increased CT dose index associated with narrower collimation in the multislice mode offsets the dose reduction at the extremes.