【作者】 张琦；

【导师】 谭长连；

【作者基本信息】 中南大学 ， 影像医学与核医学， 2010， 硕士

【摘要】 目的探讨双能量CT血管成像(dual-energy computed tomography angiography,DE-CTA)技术检测颅内动脉瘤的方法,并评估其诊断价值。材料和方法收集2009年3月至2010年4月在长治医学院附属和平医院临床拟诊为颅内动脉瘤并经过DE-CTA检查的患者54例,其中男23例,女31例,年龄从15岁～72岁,平均年龄48.2±15.7岁。54例患者均经过数字减影血管造影(digtal subtraction angiography,DSA)检查,发现颅内动脉瘤患者42例,手术证实9例。临床表现：以突发性头痛为首发症状31例,伴恶心呕吐9例；昏迷11例；以头晕为首发症状7例；长期间断头痛2-6个月者3例；视力下降、上睑下垂2例；34例患者并发蛛网膜下腔出血(subarachnoid hemorrhage,SAH),3例曾患SAH；脑内血肿形成3例。本组病例起病至DE-CTA检查时间为3小时～6个月不等。DSA在DE-CTA检查后一周内进行。采用双源CT(德国Siemens公司Somatom Difinition)患者仰卧位,下颌内收,固定头部,扫描定位像,并在定位像上选定扫描范围,从主动脉弓至颅顶,进行双能量增强CTA扫描模式。应用Ulrich Missouri(德国)高压注射器,经手背静脉以4.2ml／s团注碘普罗胺(370mgI／m1)85ml,并以相同速率追加30ml生理盐水。通过团注示踪方式智能触发扫描,跟踪点定于主动脉弓部,触发阈值为110Hu,延时4s开始自动扫描,扫描时间6s左右。扫描参数：两个球管电压分别是140kV和80kV,有效电流分别是49mAs和200mAs,准直器宽度64x0.6mm,矩阵512x512,自动重组层厚0.6mm,间隔0.3mm,螺距0.65,球管环周时间0.33s,视野219mm,总的扫描时间(延时时间与实际扫描时间之和)10.13s。由两名有经验的主治或以上医师在工作站(syngo CT 2008G)上调入所获得的140KV、80KV以及140KV和80KV两种能量混合的3组扫描数据,进行图像后处理重建,图像后处理方式包括：容积再现(volume rendering,VR)、最大密度投影(maximun intensity projection,MIP)、多平面重建(multiplanar reconstruction,MPR)、曲面重建(curved planar reconstruction,CPR)。再比较不同后处理重建方法对颅内动脉瘤及其与载瘤动脉的关系以及动脉瘤周骨性标志的显示能力；以DSA和手术结果为金标准,评价DE-CTA诊断颅内动脉瘤的敏感性及特异性；分析DE-CTA与DSA定量检测动脉瘤的相关性。结果1.采用双能量增强CTA扫描模式,54例患者均依据140KV、80KV以及140KV和80KV的混合组数据进行图像后处理,并获得满意的各种双能量CTA重建图像,包括去骨成像。2.以患者为分析单位,双能量CTA诊断颅内动脉瘤的敏感性是93.0%,特异性是100%；以动脉瘤个数为分析单位,诊断敏感性是91.8%,特异性是100%。3.双能量CTA定量测定动脉瘤与DSA有很好的相关性(分别是r=0.962、0.970、0.859；P值均<0.01)；两种方法差异无统计学意义(t=1.721、1.993、1.915；P值均>0.05)。4.VR、MP.MPR/CPR对颅内动脉瘤、载瘤动脉及动脉瘤定量测量的显示差异无统计学意义(P值均>0.05)；VR与MPR/CPR对瘤周骨性标志的显示有明显差异(P<0.01)；MIP对骨性标志不显示。结论1.双能量CTA诊断颅内动脉瘤的敏感性和特异性高,并且对动脉瘤定量测量与DSA结果具有很高的相关性,只需一次增强扫描,就可以同时获得各种双能量CTA重建图像,包括能量减影去骨的图像,是一种无创、快速、成功率高的有效检测动脉瘤的影像学方法。2.VR重建方法能够充分显示瘤周骨性解剖标志；VR、MIP、MPR／CPR重建方法都能很好显示颅内动脉瘤及其与载瘤动脉的关系。更多还原

【Abstract】 ObjectiveTo explore the methods of dual-energy computed tomography angiography(DE-CTA) in the detection of intracranial aneurysms.To evaluate the value of dual-energy computed tomography angiography in the diagnosis of intracranial aneurysms.Materials and MethodsBetween April 2009 and April 2010,54 patients from the Heping Hospital of changzhi medical college were enrolled in this project. The patients included 31 females and 23 males ranging in age from 15 to 72 years,with an mean age of 48.2±15.7 years.All the patients were underwent CTA with dual-source CT and digital subtraction angiography (DSA).9 patients were performed operation.42 patients with intracranial aneurysms were detected by both digital subtraction angiography (DSA).The clinical manifestation:31 patients had initially presented with abrupt headache,9 patients with nausea and vomit,11 patients with coma, 7 patients with vertigo,2 with vision degression,3 patients with chronic intermittent headache from 2 to 6 months.34 patients accopaning with subarachnoid hemorrhage(SAH),3 patients with SAH history.3 patients with intracranial haematoma.The patients were individually scanned from 3 hours to 6 months since falled ill.All cases were performed DSA within 1 week after DE-CTA.The patients were scanned by using DE-CTA with DSCT(Somatom Definition,Siemens Medical Systems,Germany).Patients were examined in supine position with submaxilla adducting,and head were fixed.Firstly,the site-specific image was obtained,and the scan range was selected in different orientations.Then enhanced DE-CTA mode was performed.The volume of nonionic iodinated contrast medium(Iopromide, Ultravist,370mgI/ml,Schering)were injected in opisthenar vein with a power injector(Ulrich Missouri, Ulrich Medical,Germany)at a rate of 4.2ml/s for a total of 85 milliliters,and 30 milliliters of saline flush was applied to maintain a compact bolus.Scan delay was adapted by using a bolus-tracking technique.Individual contrast timing was based on bolus tracking options of the scanner(CARE Bolus).Aortic arch was selected as Premonitioring,and the threshold was 110Hu.Scanning was started after a 4-second delay.The scan range included aortic arch up to the vertex. Scanning time was about 6s.The scanning parameters:Tube voltages were set to 140kV and 80kV for both tubes,effective current were adjusted to 49mA and 200mA,with 64×0.6mm acquisition slice width,with a 512×512 matrix.A reconstruction slice of 0.6mm,interval of 0.3mm. Gantry rotation time was 0.33s,pitch 0.65 adapted to the head.Extended field of view was 219mm.The total of scanning time was 10.13s.The data of 3 groups were transferred to a workstation(syngo CT 2008G)and automatically reconstructed,individually 140KV,80KV and composite ampho-data.The reconstruted images were processed into Volume Rendering(VR),Maximun Intensity Projection(MIP), Multiplanar Reconstruction(MPR),Curved Planar Reconstruction(CPR )for Visualizating intractanial aneurysms.Two radiologists interpreted CTA images to detect intracranial aneurysms and compared the effect of visualization between different reconstruction methods.If an aneurysm was detected,the relationship between the aneurysms predefined vessel locations for the presence of an aneurysm,and osseous surrounding structures were observed. Several morphologic characteristics were evaluated:the aneurysm maximal diameter(D) and neck(N) were measured. The diagnostic sensitivity and specificity of aneurysms were evalued compared with DSA and the finding of operations.The difference and correlation of the quantitative determination of aneurysms were compared between DE-CTA and DSA.Results1.Using enhanced DE-CTA mode,the scanned data of 54 patients were processed into reconstruction.Individually the data was 140KV,80KV and composite ampho-data.All kinds of excellent DE-CTA reconstructed imagings were gained including excellent bone elimination imagings.2.Using DSA and the finding of operations as the standard of reference,sensitivity and specificity of DE-CTA to detect intracranial aneurysms were 93.0% and 100% on a per-patient basis,91.8% and 100% on a per-aneurysm basis.3.Excellent correlation was found between DSA and DE-CTA in the quantitative diagnosis of intracranial aneurysms(r= 0.962,0.970,0.859,P<0.01)on the long,short axis and size of neck.There was no statistical difference between DE-CTA and DSA(t= 1.721,1.993,1.915,P>0.05).4.There was no statistical difference between the 4 processing methods of DE-CTA for visualizating intracranial aneurysms and adjacent structures(P>0.05).There were statistical difference between VR and MPR/CPR for visualizating osseous surrounding structures(P<0.01). The osseous surrounding structures could not displaied by using MIP.Conclusions1.There were higher diagnostic sensitivity and specificity for intracranial aneurysms by using DE-CTA technique. Excellent correlation was found between DSA and DE-CTA in the quantitative diagnosis of intracranial aneurysms.All kinds of excellent DE-CTA reconstructed imagings were gained simultaneously by using a single contrast-enhanced DE-CTA.The excellent bone elimination imagings were gained on energy subtraction principal basis.As an noninvasive and volant method,a single contrast-enhanced DE-CTA has higher achievement ratio for diagnosing intracranial aneurysms.2.The methods of VR were more integrative for visualizating osseous surrounding structures compared with the others.The methods of VR,MIP,MPR/CPR were excellent for visualizating aneurysmas and relationship between the aneurysms predefined vessel locations for the presence of an aneurysm.更多还原