胸部螺旋CT扫描的质量控制

螺旋CT采用滑环技术使扫描及成像速度加快,扫描范围增加,图像质量提高,在硬件支持下的图像后处理软件对于多方位的显示解剖结构,病理变化增加了丰富内容,有利于提高影像诊断水平,为临床提供了全方位的可靠图像。螺旋CT图像处理的质量受控于整个容积数据采集方式,技术条件和成像方法。本主要介绍胸部螺旋CT的基本原理、技术、方法,以达到对图像质量的控制。     

动态CT增强对结节样肺癌与结节样肺炎的鉴别诊断价值

目的研究动态CT增强扫描对结节样肺癌与结节样肺炎的定性价值。方法随机选择83例SPN患者,先行薄层（3．0-5．0mm）平扫,再静脉注射对比剂（优维显）100mL后,对选定的结节中心行动态CT增强扫描,测量其增强前后的CT值,并对其中47例行三维表面重建。结果肺炎性结节以重度强化为主,净增值〉60HU,动态曲线呈持续上升型;肺癌性结节以轻。中度强化为主,净增值为20-60HU,动态曲线呈缓慢持续升高型;三维重建成像显示：恶性结节以Ⅰ、Ⅱ型血管异常为主;良性结节以Ⅳ型血管异常为主。结论动态CT增强扫描中追加三维重建对孤立结节的鉴别诊断有较高价值。     

多层螺旋CT心血管参数评价急性肺栓塞严重性

目的:研究多层螺旋CT心血管参数评价急性肺栓塞(APE)严重性的价值。方法:APE患者分为严重APE组(28例)和非严重APE组(47例)两组。根据CT肺动脉内栓子阻塞部位和程度计算CT阻塞指数;测量右室短轴最大径、左室短轴最大径、右室与左室短轴最大径比、右室壁厚、主肺动脉直径及上腔静脉直径;观察室间隔是否左突。评价严重APE组和非严重APE组之间的CT心血管参数的差异是否有统计学意义。结果:严重APE组与非严重组的CT心血管参数有统计学差异(P<0.05)的指标包括:阻塞指数、右室短轴最大径、左室短轴最大径、右室与左室短轴最大径比、右室壁厚、主肺动脉直径及室间隔位置。结论:综合分析APE患者的CT心血管参数变化,有助于判断APE患者的严重性。     

CT肺动脉阻塞指数与血气分析值评价急性肺栓塞严重性的研究

目的研究CT阻塞指数与血气分析评价急性肺栓塞(APE)严重性的价值。方法接受CTPA和动脉血气分析检查并且无基础心肺疾病的APE患者共59例。利用肺动脉CT阻塞指数评价肺动脉栓子阻塞程度与范围。动脉血气分析包括PaCO2、PaO2、SaO2及P(A-a)O2。严重APE组和非严重APE组患者之间的CT阻塞指数、动脉血气分析指标之间的统计学差异用t检验评价。阻塞指数与动脉血气分析指标之间的相关性使用Spearman相关系数评价。结果严重APE组患者的PaCO2、PaO2及SaO2明显低于非严重APE组患者(P<0.01),而P(A-a)O2明显高于非严重APE患者(P<0.01)。阻塞指数分别与PaCO2、PaO2、SaO2及P(A-a)O2的相关性有统计学意义(P<0.01)。结论综合分析APE患者的肺动脉阻塞指数、血气分析指标有利于评价APE患者的严重性。     

64层螺旋CT胸部低剂量扫描方案优选的多中心研究

目的 比较自动曝光控制技术(AEC)与管电流恒定技术(CCC)2种不同低剂量MSCT扫描方案对胸部CT图像质量的影响,探讨更加合理的肺低剂量扫描参数方案.方法 采用前瞻性多中心研究方法,研究对象为7所医院就诊的280例行胸部低剂量MSCT检查的受检者,设定管电流(mA)为研究变量,方法一为AEC技术,下设噪声标准差值(SD)为25(A1)及30(A2)各1组,并设定管电流上限为80 mA,下限为10 mA;方法二为CCC技术,下设40 mA(C1)及50 mA(C2)各1组;共4组,采用同一机型64层MSCT行胸部低剂量扪描.2名放射科医师应用双肓法阅片,比较2种不同扫描技术的曝光剂量、SD值,横断面、MPR的图像质量以及体质量指数(BMI)对图像质量的影响.曝光剂量及SD比较行方差分析及t检验;图像质量比较行Mann-Whitney检验;医师对图像诊断一致性检验行Kappa分析.结果 剂量长度乘积(DLP)AEC组较CCC组明显降低[(82.62±40.31)和(110.81±18.21)mGy·cm,F=56.88,P＜0.01].AEC技术中A2组DLP较A1组低[(72.77±36.68)和(92.46±41.61)mGy·cm],差异无统计学意义(t=0.82,P＞0.05).前者SD值在肺窗[(41.50±9.58)和(40.86±7.03)HU]及纵隔窗[(41.19±7.83)和(40.92±9.89)HU]均略高于后者,差异无统计学意义(F肺窗=0.835、1.910,P值均＞0.05).横断面图像质量AEC组肺窗得分除右下肺静脉水平[(4.92±0.25)和(4.93±0.17)分]、[左膈顶上缘水平(4.91±0.27)和(4.93±0.22)分]较CCC组略低外,AEC组得分均较CCC组略高[头臂静脉上缘(4.49±0.56)和(4.38±0.64)分;主动脉弓上缘(4.86±0.23)和(4.81±0.32)分;右肺上叶支气管开口(4.87±0.27)和(4.84±0.22)分;右肺中叶支气管开口(4.90±0.25)和(4.88±0.21)分],差异无统计学意义(F=0.076～1.748,P值均＞0.05);纵隔窗得分除头臂静脉上缘水平AEC组较CCC组高[(2.57±0.77)和(2.46±0.59)分],且差异有统计学意义(F=8.459,P=0.047)外,余各层面AEC组得分均较CCC组略低[(主动脉弓上缘(3.36±0.63)和(3.45±0.60)分;右肺上叶支气管开口(3.94±0.56)和(3.95±0.51)分;右肺中叶支气管开口(3.80±0.58)和(3.87±0.50)分;右下肺静脉(3.72±0.56)和(3.78±0.53)分;左膈顶上方(3.58±0.63)和(3.68 ±0.56)分],但差异均无统计学意义(F=0.083～3.380,P值均＞0.05).MPR图像质量肺窗及纵隔窗观察均略好于CCC组(Z肺窗=-2.358,Z纵隔窗=-1.330,P值均＞0.05).偏瘦、正常或偏重人群组,A1组肺窗及纵隔窗图像质量均优于A2组,差异无统计学意义(偏瘦:Z肺窗=0.000、Z纵隔窗=0.000;正常:Z肺窗=-0.062、Z纵隔窗=-0.746;偏重:Z肺窗=-1.177、Z纵隔窗=-1.715;P值均＞0.05),但在偏重人群纵隔窗图像质量A1组更好于A2组(Z=-1.715,P=0.144).结论 AEC组总曝光剂量明显低于CCC组,而AEC组的图像质量及SD值无论在肺窗或纵隔窗均与CCC组无明显差异,故建议在胸部低剂量筛查方案选择中应用AEC技术,对偏胖者宜采用SD=25方案,对正常及偏瘦者宜采用SD=30方案.

Abstract：

Objective To compare the image quality of chest low dose CT (LDCT) using automatic exposure control (AEC) and constant current control (CCC) and explore a more reasonable scanning protocol. Methods Two hundred and eighty participants were examined with 64 CT scanner at 7 centers in China. All were divided into 4 groups. Two groups underwent LDCT using AEC with standard deviation set at 25 (A1) and 30 (A2) respectively and the tube current ranged from 10 mA to 80 mA. The other two groups underwent LDCT using CCC with tube current set at 40 mA (C1) and 50 mA (C2) respectively. The axial and MPR images were evaluated by two radiologists who were blinded to the scanning protocols.The radiation dose, noise and the image quality of the 4 groups were compared and analyzed statistically.Differences of radiation dose and noise among groups were determined with variance analysis and t test,image quality with Mann-Whitney test and the consistency of diagnosis with Kappa test. Results There was a significant lower DLP in AEC group than in CCC group [(82.62±40.31)vs ( 110.81±18.21) mGy·cm (F =56. 88 ,P ＜ 0. 01 )], whereas no significant difference was observed between group A2 and group A1 0. 05]. The noisy of AEC group was higher than that of CCC group both on lung window(41.50±9.58 vs 40.86±7.03) and mediastinum window (41.19±7.83 vs 40.92±9.89), but there was no significant difference( Flung =0.835, P=0.476, Fmediastinum =1.910, P=0.128).The quality score of axial image in AEC group was higher than that in CCC group (superior margin of the brachiocephalic vein level: 4.49±0.56 vs4.38±0.64,superior margin of the aortic arch: 4.86±0.23 vs 4.81±0.32,the right superior lobar bronchus Level:4.87±0.27 vs 4. 84 ± 0. 22, the right middle lobar bronchus Level: 4.90±0.25 vs 4.88±0.21) except on the right inferior pulmonary vein level(4. 92 ±0. 25 vs 4. 93 ±0. 17) and superior margin of the left diaphragmatic dome level (4. 91±0.27 vs 4.93±0.22) on lung window, but no significant differences (F=0.076-1.748, P＞0.05) were observed. A significant higher score in AEC group was observed on mediastinum window compared with CCC group on superior margin of brachiocephalic vein level (2.57±0.77 vs 2. 46 ± 0. 59, F = 8. 459, P ＜ 0. 05 ), however, the score of AEC group was lower than that of CCC group on other levels without significant differences (superior margin of the aortic arch:3.36 ±0. 63 vs 3.45 ±0. 60,the right superior lobar bronchus level: 3.94 ±0. 56 vs 3. 95 ±0. 51 ,the right middle lobar bronchus Level: 3.80 ±0. 58 vs 3. 87 ±0. 50,the right inferior pulmonary vein level: 3.72 ±0. 56 vs 3.78 ±0. 53, superior margin of the left diaphragmatic dome level: 3.58 ± 0.63 vs 3.68±0.56,F=0.083-3.380,P ＞ 0.05 ). The MPR image quality of AEC group was better than that of CCC group both on lung window and mediastinum window (Zlung =-2.258, Zmedlastinum=-1.330, P＞0.05). For all participants including the underweighted group, the normal group and the overweighted group, the image quality of A1 group was better than that of A2 group without significant differences (the underweighted group: Zlung=0.000, P=1.000, Zmedastinum= 0.000, P=1.000;the normal group: Zlung =-0.062, P=0.950, Zmediastinum =-0.746, P = 0.456; the overweighted group: Zlung = - 1.177, P = 0.239,Zmediastinum =-1.715, P=0.144) both on lung and mediastinum windows, and for the higher BMI participants, a better image quality was obtained in A1 group than in A2 group on the mediastinum window (Z = -1. 715, P = 0. 144). Conclusions The total radiation exposure dose of AEC group is significantly lower than that of CCC group, but no statistical significant differences are observed between both groups in image quality and noise level. The AEC technique is highly recommended in thoracic LDCT scan for screening program, and the SD25 ( SD value = 25) scan protocol is suggested for higher BMI population while the SD30 (SD value = 30) scan protocol for lower BMI population.     

320排动态容积CT灌注成像在肝硬化中临床应用研究

目的 研究320排动态容积CT在肝硬化患者灌注成像的作用以及临床上应用效果.方法 选取50例肝硬化患者及44例肝脏正常者就诊同时行肝脏320排动态容积CT灌注扫描并对结果进行比较分析.结果 肝硬化患者的肝脏曲线和正常肝脏的时间-密度曲线基本一致.肝硬化患者经灌注后左右叶参数无显著性差异.肝硬化患者的肝容积变化与HAP、HPP、HBF等肝脏血流灌注参数有关.结论 通过时肝脏灌注成像的方法可以对全肝血流灌注参数进行测量.肝硬化的程度可由肝脏血流灌注参数反应.     

64层螺旋CT与超声心动图在先天性心脏病诊断中的对比研究

目的 探讨64层螺旋CT(64-SCT)与经胸超声心动图(TTE)两种检查方法在先心病诊断中的价值.方法 收集2007年9月～2009年3月在本院经手术证实的先心病病例54例,所有患者术前均同时行64-SCT和TTE检查,以手术为金标准,评价两种检查方法的诊断准确率.结果 54例共证实畸形176处,64-SCT诊断准确率为98.3%,TTE诊断准确率为90.3%.TTE漏误诊主要为心外大血管畸形(15/18).在诊断心内畸形及心脏-大血管连接畸形方面两者无显著性差异.结论 64-SCT和超声心动图在先心病诊断中各有优势和不足,联合应用两种检查方法有助于提高复杂先心病的诊断准确率.     

200例外伤性硬膜下血肿CT诊断的分析

２００例外伤性硬膜下血肿ＣＴ诊断的分析哈尔滨医科大学第一临床医学院ＣＴ室（１５０００１）李淑艳，肖喜刚，田莉，魏庆堂庆安县医院放射线科孙继梅外伤性硬膜下血肿是颅脑损伤最常见的一种类型，死亡率较高，及时正确的诊断和治疗可降低死亡率，而ＣＴ是准确诊断该类...     

多层螺旋CT在髋臼骨折急救中的应用

髋臼骨折属严重而复杂的急性创伤,术前正确诊断和分型尤为重要。笔者通过对2 4例髋臼骨折患者MSCT图像分析,探讨其在髋臼骨折中的应用价值。1　资料与方法1.1　一般资料　对2 4例髋臼骨折患者分别摄骨盆平片和行MSCT容积扫描。其中男18例,女6例,年龄2 6～6 8岁,平均39.4岁。右髋臼骨折13例,左髋臼骨折10例,双侧骨折1例。15例手术治疗。1.2　扫描方法　使用东芝Aquilion多层螺旋CT机,扫描范围自髂骨体至坐骨结节,层厚2mm×4 ,螺距3.5 ,重建间隔1mm。应用多平面重建(MPR)和容积重建(SVR)、表面遮蔽重建(SSD)、电子分离技术重建图像。2…