64排CT肾脏、肾上腺、肾动脉三合一扫描在继发性高血压病因筛查中的应用

目的 探讨64排CT肾脏、肾上腺、肾动脉三合一扫描在继发性高血压病因筛查中的应用价值.方法 利用飞利浦64排螺旋CT进行肾脏、肾上腺、肾动脉三合一扫描增强扫描,69例获得原始横断面图像后,采用容积再现(VR)、最大密度投影(MIP)、多平面重建(MPR)技术处理图像,29例行DSA检查或手术治疗.结果 所有病例CT三合一扫描1次检查均获成功,显示肾上腺疾病25例,肾脏实质性病变9例,肾动脉狭窄35例.结论 64排CT一次检查可实现对肾脏、肾上腺、肾动脉的快速联合排查,是继发性高血压病因的有效筛查手段,具有重要临床应用价值.     

64排螺旋增强扫描对诊断非小细胞肺癌TNM分期的价值分析

目的 探讨64层螺旋CT增强扫描效果与肺癌TNM分期的关系及其临床应用价值.方法 20例病理确认的非小细胞肺癌患者行64排螺旋CT灌注扫描,灌注扫描后1-2周内行肺癌根治术.结果 64排螺旋CT分期诊断I、II、III、Ⅳ的有效率分别为50.0%、80.0%、80.0%和66.7%.II、III的诊断有效率明显高于I、Ⅳ期的诊断有效率(P<0.05).结论 肺癌CT强化扫描诊断的有效率与肺癌TNM分期等癌生物行为存在一定的相关性,但是具体性还需要我们进一步研究.     

CTA冠脉成像的临床应用研究

目的 探讨64排螺旋CT,CTA技术在冠状动脉病变中的临床应用,为临床后续治疗提供依据.方法对32例临床诊断或可疑诊断冠心病的患者做64排螺旋CTA检查,对所有扫描图像采用西门子工作站提供的各种分析软件进行后重建,观察冠状动脉管腔情况并进行分析判定.结果 CTA 成像一次检查可完成冠状动脉的评价,图像清晰,方便、安全.结论 64排螺旋CT可作为冠状动脉血管情况的筛查.     

320排CT动态容积扫描在颞下颌关节疾病中的应用价值

目的探讨320排CT动态容积扫描颞下颌关节(TMJ)在扫描方法、成像质量、临床作用等方面相对于其他影像检查的优势。方法对68例,其中56例口腔科和12例整形外科的患者分别用东芝320排CT和东芝64排螺旋CT进行扫描并进行二、三或四维重建,23例同时进行1.5T MRI检查,对三种检查方法进行质量评估和结果分析。结果 320排四维重建获得的动态电影图像在图像质量、细节显示、时间空间分辨率、立体阅片上均存在较大优势。结论 TMJ的320排CT动态容积模式扫描速度快,成像质量高,无运动伪影,尤其是独特的电影播放方式,有助于临床诊断及治疗方案的制定。     

64排CT在诊断主动脉夹层中应用的临床价值分析

目的 分析64排CT应用于主动脉夹层中的诊断效果,探讨其临床价值.方法 收集35例主动脉夹层患者作为研究对象,所有患者均行CT检查,观察诊断结果.结果 以手术病理结果为标准,64排CT诊断符合率为94.28％,内侧真腔32例,外侧真腔3例.结论 64排CT诊断主动脉夹层,具有无创无痛、可重复检查、准确性高等优势,能够清...     

64排螺旋CT的应用

该文综述了64排螺旋CT具有扫描速度快、扫描层薄、扫描范围广、扫描射线剂量低等优点。多种后处理技术在临床应用,所获得影像清晰。     

支气管三维CT成像技术在小儿支气管扩张中的临床应用

目的:分析支气管三维CT成像技术在小儿支气管扩张中的临床应用。方法:随机选取2015年4月至2017年4月期间在芜湖市第二人民医院门诊就诊的40例支气管扩张小儿患者,均行64排螺旋CT三维成像扫描确诊,分别对囊状、柱状、静脉曲张型及混合型进行分析。结果:40例患者支气管的动脉主干部位均表现有明显的不同程度的扩张及弯曲、迂回,扩张部位累及肺部下方,支气管内供血动脉的分支间存在交叉沟通现象,诊断囊状型6例,柱状型10例,静脉曲张型15例,混合型9例。结论:64排螺旋CT三维成像技术对支气管扩张患者的诊断准确、清楚、全面,且操作简便、无创,值得在临床诊断中进一步推广及应用。     

儿童先天性体动脉-肺动脉瘘4例并文献复习

目的总结临床表现为大量咯血的先天性体动脉-肺动脉瘘患儿的临床特点及诊治经验。方法回顾性收集首都医科大学附属北京儿童医院2007年3月至2008年2月诊断为先天性体动脉-肺动脉瘘4例患儿的临床资料,总结其临床表现、胸部X线片、胸部64排CT增强扫描三维容积再现（3D-VR）、数字减影血管造影（DSA）、治疗及随访情况。结果男1例,女3例,最大发病年龄为11岁,最小发病年龄为2个月,主要表现为咯血。1例有杵状指,3例未见特异性体征。胸部X线片检查：3例未见异常,1例示肺间实质浸润。胸部64排CT增强扫描3D-VR检查：1例提示支气管动脉迂曲,但未见异常交通;1例导管栓塞治疗（TCE）后示右侧支气管动脉扩张迂曲,并与肺动脉相通可能性大,考虑支气管动脉-肺动脉瘘;1例提示支气管动脉-肺动脉瘘;1例未见异常。3例DSA提示为支气管动脉-肺动脉瘘,病变部位均位于右下肺,并行TCE。随访至2009年2～5月,1例复发,表现为痰中带血,胸部64排CT增强扫描未见异常,余3例未复发。3例怀疑为遗传性出血性毛细血管扩张症（HHT）,1例考虑为HHT高度危险者。结论体动脉-肺动脉瘘可造成大量咯血。胸部X线片一般无特异性表现,胸部64排CT增强扫描3D-VR可显示病变部位,明确诊断需行DSA。可采用TCE治疗。TCE远期效果应进行长期随访予以明确。     

64排螺旋CT冠脉成像效果与影响因素研究

目的 探讨64排螺旋CT冠脉成像中影响图像质量的各种因素及其影响程度以及评估冠脉狭窄的效果.方法 通过838例临床疑似冠心病患者的6_4排螺旋CT冠脉成像,并以其中218例在1周内进行的常规冠状动脉造影为标准,分析64排螺旋CT冠脉成像在评估冠脉狭窄的灵敏度、准确率、阳性预测值和阴性预测值.结果 心率、心率变化幅度、延迟时间设定、β受体阻滞剂、呼吸频率、屏气合作与否、造影剂注射总量与速度、图像重建时相、冠状动脉钙化、扫描参数、患者年龄性别、机器软硬件性能等是影响64排螺旋CT成像质量的因素.64排螺旋CT冠脉成像评估冠脉狭窄的准确率为95.9%,阳性与阴性预测值分别为92.3%、90.0%.结论 得到了影响64排螺旋CT冠脉成像的各种因素,分析了减少和消除这些因素影响的方法.在评估冠脉狭窄方面,64排螺旋CT冠脉成像基本能满足临床要求. Abstract： Objective To study the various factors that influence image quality of 64-slice spiral CT coronary artery imaging, their impact extent and the assessment effect of coronary artery stonnsis. Methods Through examination of 838 clinical coronary heart disease suspect patients, by 64-slice spiral CT coronary artery imaging, in which, 218 patients were also examined by conventional coronary angiagraphy in a week, we took the conventional coronary angiography as the standard, analyzed the 64-slice spiral CT coronary artery imaging in the assessment of coronary artery stenosis by sensitivity, accuracy, positive predictive value and negative predictive value. Results The factors which affect the image quality of 64-slice spiral CT coronary artery imaging include heart rate, heart rate change range, delay time setting, β-blocker, respiratory rate, breath-holding or not, total amount of contrast medium and the speed of injection, image reconstruction phase, coronary artery calcification, the scan parameters, age and sex of patients, machine     

肺动脉栓塞的64层螺旋CT血管成像技术分析

目的 从技术上探讨64层螺旋CT肺动脉造影对肺栓塞的诊断的价值.方法 对62例临床疑诊肺栓塞的患者行64排螺旋CT肺动脉造影检查,采用最大密度投影(MIP)、多平面重建(MPR)、曲面重建(CPR)、容积漫游(VR)及仿真内窥镜等后处理技术,分析所获得的相关CT资料.结果 64排多层螺旋CT肺动脉造影可较准确、清晰、全面地显示24例累及肺动脉及其分支共152处栓子的位置、形态、范围和程度.结论 64排多层螺旋CT肺动脉造影是肺栓塞及时准确无创的诊断方法,是临床诊断肺栓塞的首选筛查办法,对肺动脉栓塞的诊断具有明显的技术优势.     

自动管电流调制技术在头颈部CTA中的应用

目的探讨头颈部CT血管成像(CTA)扫描中Z轴自动管电流调制技术(ATCM)对图像质量、辐射剂量的影响。方法86例头颈部CT增强血管成像的病例,采用常规扫描成像(固定管电流)和Z轴ATCM成像各43例。常规成像组中男性27例,女性16例;年龄39～70岁,平均年龄50岁。ATCM组中男性24例,女性19例;年龄41～72岁,平均年龄53岁。由2位有经验的影像专业人员分别评价图像质量,比较单次扫描的CT剂量加权指数(CTDIvol)、剂量长度乘积(DLP)。结果在扫描范围、扫描参数(kV、mAs、p、TH等)、造影剂注射速率、注射部位完全相同的情况下,两种扫描方法的成像质量比较差异无统计学意义(P>0.05);采用Z轴ATCM的DLP是常规扫描成像法的0.74倍。结论采用Z轴ATCM能明显降低总曝光量和累计DLP,有效降低患者的辐射剂量。     

A comprehensive study on the relationship between the image quality and imaging dose in low-dose cone beam CT

While compressed sensing (CS)-based algorithms have been developed for the low-dose cone beam CT (CBCT) reconstruction, a clear understanding of the relationship between the image quality and imaging dose at low-dose levels is needed. In this paper, we qualitatively investigate this subject in a comprehensive manner with extensive experimental and simulation studies. The basic idea is to plot both the image quality and imaging dose together as functions of the number of projections and mAs per projection over the whole clinically relevant range. On this basis, a clear understanding of the tradeoff between the image quality and imaging dose can be achieved and optimal low-dose CBCT scan protocols can be developed to maximize the dose reduction while minimizing the image quality loss for various imaging tasks in image-guided radiation therapy (IGRT). Main findings of this work include (1) under the CS-based reconstruction framework, image quality has little degradation over a large range of dose variation. Image quality degradation becomes evident when the imaging dose (approximated with the x-ray tube load) is decreased below 100 total mAs. An imaging dose lower than 40 total mAs leads to a dramatic image degradation, and thus should be used cautiously. Optimal low-dose CBCT scan protocols likely fall in the dose range of 40-100 total mAs, depending on the specific IGRT applications. (2) Among different scan protocols at a constant low-dose level, the super sparse-view reconstruction with the projection number less than 50 is the most challenging case, even with strong regularization. Better image quality can be acquired with low mAs protocols. (3) The optimal scan protocol is the combination of a medium number of projections and a medium level of mAs/view. This is more evident when the dose is around 72.8 total mAs or below and when the ROI is a low-contrast or high-resolution object. Based on our results, the optimal number of projections is around 90 to 120. (4) The clinically acceptable lowest imaging dose level is task dependent. In our study, 72.8 mAs is a safe dose level for visualizing low-contrast objects, while 12.2 total mAs is sufficient for detecting high-contrast objects of diameter greater than 3 mm.     

腕关节多层螺旋CT扫描参数、图像质量和辐射剂量的关系

目的 研究尸体标本腕关节多层螺旋CT （MSCT）扫描参数、图像质量和辐射剂量的相互关系。 方法 腕关节尸体标本共4例,依次编为1~4号。扫描机型为Siemens Somatom Sensation16 螺旋CT扫描仪。每例尸体标本共进行11组扫描,第1~11组扫描采用的电流和电压依次为：1.80mAs、80kV;2.80mAs、100kV;3.80mAs、120kV;4.100mAs、80kV;5.100mAs、100kV;6.100mAs、120kV;7.120mAs、80kV;8.120mAs、100kV;9.120mAs、120kV;10.100mAs、100kV;11.100mAs、100kV。第1～11组均采用16×0.75mm准直器。第1～9组采用的螺距均为0.55,第10组和第11组扫描采用的螺距分别为1.0和1.5。3号标本加1组高电压、高电流扫描：140kV、300mAs。以上扫描球管旋转1周均为0.5s。扫描完成后重建1.0mm层厚、0.5mm间距薄层图像并传至Siemens多功能后处理工作站（MMWP）进行冠状位重组。比较不同扫描参数时的辐射剂量及冠状位重组图像质量。 结果 腕关节标本在不同扫描条件下重组的冠状位图像质量无明显差异。辐射剂量与电流的改变呈直线正相关;辐射剂量与电压的改变呈曲线正相关;辐射剂量与螺距的改变无明显相互关系。 结论 辐射剂量与各种扫描参数的关系各不相同,扫描参数、图像质量和辐射剂量的相互关系对临床工作有指导意义。     

图像域迭代重建算法对腹部CT平扫图像质量和辐射剂量的影响

目的:探讨图像域迭代重建算法对腹部CT平扫图像质量及辐射剂量的影响。 方法:以辽阳市中心医院2017年1月~2018年4月行腹部CT平扫的150例患者为研究对象,依据就诊先后顺序随机将其分为观察组与对照组,各75例。均行自动毫安控制技术扫描,管电压均为130 kV。观察组预设图像质量参考毫安秒150 mAs,行图像域迭代重建算法重建;对照组预设图像质量参考毫安秒250 mAs,行滤波反投影重组。通过CT值、图像噪声SD、图像信噪比、对比噪声比评价两组图像客观质量,并行图像质量主观评价,记录两组CT剂量容积指数。 结果:观察组肝脏、脾脏的图像噪声SD均显著低于对照组,图像信噪比均显著高于对照组,差异有统计学意义（P<0.05）;CT值、对比噪声比、主观整体质量评分两组比较差异均无统计学意义（P>0.05）;观察组CT剂量容积指数为（10.02±2.85） mGy,显著低于对照组的（15.68±4.36） mGy,差异有统计学意义（P<0.05）。 结论:图像域迭代重建算法不仅能保证腹部CT平扫图像质量,而且能有效减少辐射剂量。     

A comparison between low-dose and standard-dose non-contrasted multidetector CT scanning of the paranasal sinuses

Purpose

To compare the image quality of the low-dose to the standard-dose protocol of MDCT scanning of the paranasal sinuses, based on subjective assessment and determine the radiation doses to the eyes and thyroid gland and dose reduction between these two protocols.

Materials and Methods

31 adult patients were scanned. Prior to scanning, thermoluminescent dosimeters (TLDs) were placed at 4 sites: outer canthus of right eye, outer canthus of left eye, inner canthus and anterior neck (thyroid gland). Every patient was scanned twice using the standard-dose protocol (100mAs) followed by the low-dose protocol (40mAs). The images were reviewed by 3 radiologists. Wilcoxon test was used as the test of significance for the image quality assessments. The paired sample t-test was used as the test of significance for the analysis of the radiation doses measured by the TLDs.

Results

Of the 30 patients selected for analysis, this study showed no significant difference in the scores for the diagnostic image quality and the anatomical structures assessments between the two protocols. The average calculated mean entrance surface doses and standard deviation for the standard-dose and low-dose protocols were 12.40±1.39 mGy and 5.53±0.82 mGy respectively to the lens and 1.03±0.55 mGy and 0.63±0.53 mGy respectively to the thyroid gland.

Conclusion

The reduction of mAs from 100 to 40 resulted in a significant reduction of the radiation doses to the lens and thyroid gland by 55.4% and 38.8% respectively without causing any significant effect to the diagnostic image quality and assessment of the anatomical structures.     

不同剂量对比剂在64排螺旋CT脑动脉成像中的比较研究

目的比较64排螺旋CT脑动脉成像(CTA)检查中不同剂量对比剂脑动脉显影质量,探讨在保证图像质量的前提下,使用合适的对比剂剂量。方法怀疑或已知颅内血管性病变患者183例,其中男性97例,女性86例;年龄41~75岁,平均年龄56岁。行脑CTA,对比剂为碘普罗胺(370 mg I/m L)。按对比剂注射量分成3组,A组50 m L者64例,B组70 m L者60例,C组90 m L者59例。注射对比剂之后用相同流速0.9%氯化钠溶液30 m L冲刷,对比剂流速4.5 m L/s。测量左右侧颈内动脉、大脑前动脉A2段、大脑中动脉M2段、大脑后动脉P2段和基底动脉、大脑大静脉、上矢状窦、优势乙状窦,共12处CT值;图像质量由2名高年资放射诊断医生依据动脉内对比剂充盈、动脉轮廓、静脉显影、诊断可靠性情况按5分制评分。结果 3组患者年龄、性别、心率及体质量指数差异无统计学意义(P0.05)。183例患者检查均成功,3组间图像质量评分差异无统计学意义(P0.05);A组右侧A2段、上矢状窦、乙状窦强化较B组和C组低,差异有统计学意义(t=-2.365,P=0.033;t=-2.576,P=0.021;t=-2.782,P=0.019;t=-3.014,P=0.006);其余血管CT值差异无统计学意义(P0.05)。图像质量上B组和C组动脉轮廓显示较A组好,但是A组静脉显影较B和C组更少。结论 64排螺旋脑CTA中使用对比剂50 m L(370 mg I/m L)不影响图像质量,还可减少对比剂使用的不良反应,并减轻患者经济负担。     

常规头部CT螺旋扫描与轴扫描模式的影像质量对照

目的通过头部CT螺旋扫描和轴扫描两种不同扫描模式的影像质量对照,探讨常规头部CT采用螺旋扫描模式取代轴扫描模式的可行性。方法 40例患者,其中男性24例,女性16例;年龄18～74岁,平均年龄46岁。分别接受头部CT螺旋扫描和轴扫描两种不同模式扫描,轴扫描参数:140kV、170mA用于颅底部;120kV、150mA用于颅脑部,每周2s。螺旋扫描参数:120kV,150mA,每周0.6s。扫描剂量直接取自设备剂量指示值(CTDI和DLP)。影像质量分别由2位专家采用双盲法,对头部CT的颅底、脑灰-白质层面及全部影像逐层进行CT值测量评估。结果常规头部CT螺旋扫描模式较轴扫描模式可有效去除颅底部伪影,并能减少扫描时间和扫描剂量(轴扫描模式与螺旋扫描模式对比,CTDI 55.43 mGy/37.80 mGy;DLP 662.10 mGy.cm/498.28 mGy.cm;扫描时间12.0 s/7.2 s)(P<0.001)。结论常规头部CT螺旋扫描模式的影像质量完全可与轴扫描模式相媲美,并可取代轴扫描模式。同时常规头部CT螺旋扫描模式还具有可减少扫描时间和辐射剂量,并可进行影像的二维和三维后处理,有利于提高微小病灶正确诊断率的优越性。     

Multi-detector row CT scanning in Paleoanthropology at various tube current settings and scanning mode

The purpose of this study was to determine the optimal tube current setting and scanning mode for hominid fossil skull scanning, using multi-detector row computed tomography (CT). Four fossil skulls (La Ferrassie 1, Abri Pataud 1, CroMagnon 2 and Cro-Magnon 3) were examined by using the CT scanner LightSpeed 16 (General Electric Medical Systems) with varying dose per section (160, 250, and 300 mAs) and scanning mode (helical and conventional). Image quality of two-dimensional (2D) multiplanar reconstructions, three-dimensional (3D) reconstructions and native images was assessed by four reviewers using a four-point grading scale. An ANOVA (analysis of variance) model was used to compare the mean score for each sequence and the overall mean score according to the levels of the scanning parameters. Compared with helical CT (mean score=12.03), the conventional technique showed sustained poor image quality (mean score=4.17). With the helical mode, we observed a better image quality at 300 mAs than at 160 in the 3D sequences (P=0.03). Whereas in native images, a reduction in the effective tube current induced no degradation in image quality (P=0.05). Our study suggests a standardized protocol for fossil scanning with a 16×0.625 detector configuration, a 10 mm beam collimation, a 0.562:1 acquisition mode, a 0.625/0.4 mm slice thickness/reconstruction interval, a pitch of 5.62, 120 kV and 300 mAs especially when a 3D study is required.     

Evaluation of radiation dose and image quality following changes to tube potential (kVp) in conventional paediatric chest radiography

Purpose

A study of radiation dose and image quality following changes to the tube potential (kVp) in paediatric chest radiography.

Materials and Method

A total of 109 patients ranging from 1 month to 15 years were included in two phases of the study. Phase 1 investigated the range of entrance surface air kerma (ESAK) values received from patients exposed to the existing exposure factors. In the second phase, new exposure factors using recommended values of tube potential (kVp) with reduced mAs were used. ESAK values were measured using thermoluminescent dosemeters (TLDs). Image quality in both phases was evaluated using image quality criteria proposed by the Council of the European Communities (CEC). Results of both techniques were analysed for any differences.

Results

The overall mean ESAK before the changes was 0.22 mGy (range: 0.05-0.43) Following changes in tube potential, the overall mean reduced to 0.15 mGy (range: 0.03-0.38), a significant reduction by 34%. The interquartile range was reduced from 45% to 40%. However, doses to those below a year in age still remained high. Assessment of image quality was found to have no significant differences as far as the two techniques used were concerned. However, higher image scores were achieved using higher kVps.

Conclusion

Significant dose reduction was achieved through appropriate changes in tube potential and reduction of mAs without any loss in image quality.     

多排螺旋CT低剂量扫描高分辨率重建在新型冠状病毒肺炎筛查中的应用

目的:探讨多排螺旋CT（MDCT）低剂量扫描高分辨率重建在新型冠状病毒肺炎（COVID-19）筛查中的应用价值。方法:选取2020年2月1日~3月1日间就诊的66例疑似COVID-19肺炎患者作为研究对象,将66例患者随机平均分为2组,分别实施胸部常规剂量CT扫描（n=33, 120 kV, 300 mAs）和胸部低剂量CT扫描（n=33,100 kV,70 mAs）,其中常规剂量组采用512×512矩阵,低剂量组采用1 024×1 024矩阵。同时对胸部低剂量组用4种不同权重的迭代算法进行处理（30%、50%、70%、90%）,对比两种检查模式的辐射剂量和图像质量。结果:低剂量组的有效辐射剂量为（1.81±0.14） mSV,与常规剂量组（6.83±0.68） mSV相比降低73.5%（P<0.05）;采用1 024大矩阵、90%权重迭代算法的低剂量组图像的CNR、SNR均略低于采用512常规矩阵、90%权重迭代算法的常规剂量组,但差异无统计学意义（SNR:5.11±0.75 vs 5.38±0.41,CNR:5.37±0.33 vs 5.44±0.51, P>0.05）;低剂量组患者的肺窗、纵膈窗图像质量主观评分低于常规剂量组,但差异无统计学意义（肺窗:3.30±0.72 vs 3.39±0.78;纵膈窗:3.15±0.90 vs 3.36±0.82, P>0.05）。结论:使用MDCT进行胸部低剂量扫描,同时采用高分辨率重建技术及90%权重迭代算法可用于COVID-19肺炎筛查,可在保证图像质量的前提下显著降低患者所受辐射剂量。