电子束CT的新进展

电子束ＣＴ的新进展戴汝平电子束ＣＴ（ｅｌｅｃｔｒｏｎｂｅａｍｃｏｍｐｕｔｅｄｔｏｍｏｇｒａ－ｐｈｙ，简称ＥＢＣＴ）又称超高速ＣＴ，由美国Ｂｏｙｄ博士于１９８３年发明并应用于临床。ＥＢＣＴ由电子束扫描替代了Ｘ线管与检测器的机械扫描，因而扫描速度提高近百...     

多层螺旋CT在肝脏肿瘤诊断中的应用

自 1973年Ｈｏｕｎｓｆｉｅｌｄ发表第一篇关于ＣＴ的文章至今 ,不到 3 0年的时间里ＣＴ技术已经历了几代更新。 2 0世纪 90年代后期出现并投入使用的多层螺旋ＣＴ(ｍｕｌｔｉ ｄｅｔｅｃｔｏｒｒｏｗｈｅｌｉ ｃａｌＣＴ ,ＭＤＨＣＴ)结合了多排探测器及螺旋容积扫描的优点 ,大大提高了扫描速度和图像质量 ,使一次屏气大范围薄层扫描和一次注药多期扫描成为可能 ,为疾病的诊断提供了更全面、清晰、直观的影像依据。ＭＤＨＣＴ无论在扫描速度、图像质量还是后处理效果均明显优于传统及单层螺旋ＣＴ(ｓｉｎｇｌｅ ｄｅｔｅｃｔｏｒｒｏｗｈｅ…     

电子束CT双期扫描定量评估肝脏增强程度

应用电子束ＣＴ双期扫描定量评估造影剂注射速度和注射方式与肝脏增强的关系。材料和方法：１７３例可疑肝脏病变者（２７～８６岁）分为两个实验组，均行电子束ＣＴ双期扫描。实验一（三组）应用单相注射和双相注射，实验二（四组）应用不同注射速度和不同延迟扫描时间。两组均行平扫和动静脉期扫描，测量各参数值并作统计学分析。结果：单相注射和双相注射时，肝脏增强的各参数值不同；注射速度和延迟扫描时间不同，肝脏增强的各参数值亦不同。平衡期出现的时间与注射方式、注射速度和延迟扫描时间有关。结论：在肝脏双期ＣＴ扫描时，恰当的注射方式、注射速度和延迟扫描时间可增加病灶与肝脏实质间的密度差，有利于提高病灶的检测率。     

电子束CT在心血管系统疾病诊断中的应用

电子束与普通ＣＴ相比，其主要特点是电子枪取代了Ｘ线球管，从而使扫描速度大大加快，时间分辨率的极大提高，使之实现了对心血和病的检查，本文全面介绍了ＥＢＣＴ设备结构及其心血管系统疾病诊断中的最新进展，在此方面显示了较高的应用价值。     

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。     

主动脉不典型夹层的电子束CT诊断

目的 评价电子束CT（EBCT）在主动脉不典型夹层诊断中的临床应用。方法 1994年5月至2000年4月15000例EBCT检查中诊断主动脉夹层263例,其中25例为不典型夹层。男21例,女4例。全部患者均以主诉急性胸痛入院检查。采用Imatron 150-XP型EBCT扫描机,连续容积增强扫描,层厚3mm,扫描时间为0．1s。扫描范围自主动脉弓水平至左右髂动脉分叉处,共140层。结果 不典型夹层EBCT血管造影（EBCTA）：直接征象为:(1)25例主动脉壁均呈半月状或环状增厚,达5－23mm,平均15．3mm,无内膜破裂形成的双腔主动脉征象,CT值50－87HU,累及长度为2．5－49．0cm,平均16．3cm;（2）内膜钙化移位5例;（3）6例治疗后EBCT随访,管壁厚度呈动态变化。间接征象为：（1）主动脉壁增厚溃疡形成7例;（2）动脉粥样硬化性改变12例。上述征象结合临床急性胸痛病史,诊断可以成立。病变累及升主动脉（StanfordA型）6例;仅累及降主动脉（StanfordB型）19例。全部病例临床均采取保守治疗,其中6例EBCT复查,3个月至1年血肿吸收。结论 急诊胸痛鉴别诊断中EBCT对主动脉不典型夹层诊断是一种无创、安全、有效的诊断方法,且便于治疗后随诊观察。     

电子束CT双期扫描评价肝脏血管瘤

目的 :应用电子束 CT(EBCT)双期扫描技术评价肝脏血管瘤 ,拟期提高 CT诊断血管瘤的特异性和准确性。方法 :经影像学检查怀疑肝脏病变者 32例均行 EBCT动静脉期扫描和病灶延迟扫描。应用 EBCT SS模式 0 .3 s SVS扫描程序 ,静注造影剂10 0～ 15 0 ml,速度为 3.5 ml/ s,动脉期扫描为注射造影剂后 15～ 2 0 s,静脉期为 5 5～ 6 0 s,延迟扫描为注射造影剂后 5～ 15 min。确诊方式为手术 ,穿刺和随访。结果 :EBCT诊断血管瘤 47个 (32例 ) ,直径为 1.0～ 10 cm。 CT表现为 :动脉期呈一致性高密度、实质性增强、低密度 ;静脉期呈一致性高密度、实质性增强和向心性充盈。动脉期门静脉显影 16个。结论 :血管瘤的增强类型与其内部结构相一致 ,双期扫描结合病灶延迟扫描技术可提高诊断血管瘤的准确性 ,特别适于不常见血管瘤     

儿童期肝脏肿瘤的CT诊断

儿童期肝脏肿瘤的ＣＴ诊断李子平，郑可国，许达生笔者搜集１３例经ＣＴ检查并手术病理证实的儿童期肝脏肿瘤进行分析，旨在对其ＣＴ诊断有进一步的认识。临床资料简介患者以腹痛或被发现腹部包块来院检查，体检可发现上腹部包块或肝肿大，余资料见附表。全部病例都作ＣＴ...     

电子束CT对肾脏临床血流灌注研究

目的 探讨电子束CT应用于肾脏血流灌注的价值。材料与方法 应用电子束CT血流序列对40例正常人和20例血流减少性肾病进行检查，分别测量强化高峰时间、CT值上升时间、高峰CT值、CT值增幅和血流灌注量等。结果 血流减少肾脏的强化高峰时间比正常延迟，CT值上升时间延长；血流减少肾脏皮质的CT值增幅和强化程度明显低于正常；正常和异常血流量也有非常显著差别。结论 电子束CT可对血流减少性肾病进行动态观察CT值的变化，判断肾脏血流减少程度，测量肾脏血流灌注量。     

肝脏肿瘤的动态CT扫描

Dynamic CT manifestations in 44 cases of hepatic tumors proved by pathology were reviewed. 30 were hepatoma, 6 metastatic tumor, 7 cavernous hemangioma and 1 adenoma. 50 ml of contrast medium were administered as a bolus injection, and scanning was performed at 15, 25, 60, 120 and 300 sec after injection. The tumor enhancement patterns were divided into 3 types based on time-density curve. Type 1 manifested rapid and prolonged marked tumor enhancement; Type 2 was characterized by a rapid rise followed by a rapid decline in tumor density; In type 3 there was no significant change over time in density of the tumor. All cavernous hemangiomas belonged to type 1. Type 2 and 3 were not specific. Parafocal enhancement which occurred in 83.3% of primary hepatic carcinoma in this article and without false positive cases was considered by the authors to be pathognomonic of hepatoma. Evaluation was also made of dynamic CT in treatment planning of hepatic tumors.     

螺旋CT多期增强扫描对肝脏炎性假瘤的诊断

肝脏炎性假瘤 (ｉｎｆｌａｍｍａｔｏｒｙｐｓｅｕｄｏｔｕｍｏｒｏｆｌｉｖｅｒ ,ＩＰＬ)少见 ,195 3年由Ｐａｃｋ首次报道 ,目前国内外文献不多。随着影像技术的发展 ,特别是螺旋ＣＴ的应用 ,对ＩＰＬ的诊断符合率日益提高。本文就ＣＴ螺旋多期增强扫描对ＩＰＬ的诊断及鉴别诊断进行综述。1　病因病理ＩＰＬ的病因目前尚不十分清楚 ,可能与感染有关。细菌通过胆管或门静脉侵入肝脏 ,在肝实质内形成混合有胆管上皮、肝细胞或伴静脉内膜炎的急性渗出性病灶 ,逐步纤维化形成炎性假瘤[1～ 3 ] ,所以ＩＰＬ与结石引起的胆汁淤积 ,复发化脓性胆…     

多层面CT在肝移植受体术前评估中的应用

目的:探讨多层面CT在肝移植受体术前评估中的应用价值.材料和方法:我们总结分析了自2003年11月至2004年8月52例接受多层面CT检查的晚期肝病患者.采用薄层动态增强扫描,横断面图像 CT血管造影技术,评估肝脏实质病变及血管变异情况.结果:其中接受肝移植手术26例,其中有6例肝动脉变异,与术前判断完全吻合.5例门脉癌栓形成及5例血栓形成中各有1例误诊.结论:多层面CT是一种快捷、无创、价廉的检查手段,可为肝移植受体术前评估提供详尽且准确的解剖及病变信息.     

常规CT肝脏增强扫描出现灌注异常1例报告

男 ,5 2岁。因右胸痛伴咳嗽 1年余 ,气喘 2月加重 1ｄ而入院。患者 1年前无明显诱因出现右胸痛呈间歇性钝痛 ,无放射 ,伴咳嗽 ,偶咳白色泡沫痰 ,痰中带血丝 ,无畏寒发热及胸闷气促。曾于外院行纤维支气管镜检查发现右肺中叶肺癌 ,病理示 :“小细胞未分化癌”。胸片示 :右侧胸腔积液 ,右中叶肺不张 ,考虑右肺癌。Ｂ超 :右侧胸腔积液 ,胰腺肿物 ,怀疑肝转移。ＣＴ检查 :使用美国ＧＥ公司Ｓｙｔｅｃ 40 0 0型ＣＴ机 ,采用 10ｍｍ层厚 ,间距 10ｍｍ ,扫描时间为 1.8ｓ ,人工肘静脉注入欧乃派克 5 0ｍｌ行肝脏增强扫描。注射造影剂后 6 0ｓ左右扫…     

Quantitative Evaluation of Liver Function with MRI Using Gd-EOB-DTPA

Objective

Gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) is a newly developed MR contrast agent. After intravenous injection, Gd-EOB-DTPA is gradually taken up by the hepatocytes and eventually excreted via the biliary pathway without any change to its chemical structure. Because of these characteristics, it can be used as a tracer for quantitative liver function testing. The purpose of this study is to develop a noninvasive method of quantitation of the hepatic function using Gd-EOB-DTPA through the deconvolution analysis.

Materials and Methods

Adult New Zealand white rabbits (n = 10, average body weight = 3.5 kg) were used in the present study. Hepatic injury was induced to by the intragastric administration of carbon tetrachloride (CCl4) three times a week for three weeks. Liver enzyme (aspartate aminotransferase, AST; alanine aminotransferase, ALT) levels and the plasma indocyanine green (ICG) retention rate 15 minutes after an intravenous injection of ICG (ICG R15), was checked before and after the three-week administration of CCl4. At the end of experimental period, an observer "blinded" to the treatment given the rabbits performed the histological examination. MRI studies were performed before and after the three-week administration of CCl4 on a 1.5 T scanner using a human extremity coil. After intravenous bolus injection of Gd-EOB-DTPA (0.3 mL of Gd-EOB-DTPA freshly prepared in 2.7 mL of normal saline) through the ear vein, the 250 axial single level dynamic MR images were obtained using a fast low angle shot (FLASH, TR/TE = 11/4.2 msec, flip angle = 15, acquisition time 1 second, slice thickness = 5 mm, matrix = 128×128, field of view = 120 mm) sequence with 1.5 sec time intervals. The time-intensity curves were obtained at the abdominal aorta and the liver parenchyma that was devoid of blood vessels. Deconvolution analysis of the aortic (input function) and hepatic parenchymal (output function) time-intensity curves was performed with a modified Fourier transform technique to calculate the hepatic extraction fraction (HEF). The presence and type of hepatic injury were determined by the histopathologic examination and statistical analysis of the changes of the hepatic enzyme levels, the ICG R15 and Gd-EOB-DTPA HEF values between the time before and after CCl4 administration with Wicoxon signed rank test. Correlation between the Gd-EOB-DTPA HEF and the change of the ICG R15 were analyzed with Pearson''s correlation coefficient.

Results

Histopathologic examination showed findings that were compatible with hepatic fibrosis caused by chronic liver injury. The initial blood biochemical studies before the administration of carbon tetrachloride showed that the mean AST and ALT levels were 39.8±5.2 IU/L and 59.1±11.7 IU/L, respectively. The AST and ALT levels increased to 138.4±50.5 IU and 172.0±71.6 IU/L, respectively, after the three week administration of CCl4. The ALT and AST levels were significantly increased after the three weeks of CCl4 administration (p = 0.018). The ICG R15 values were 4.47±2.08% and 19.43±3.98% before and after three-week administration of CCl4, respectively. The ICG R15 values were significantly increased after hepatic injury (p = 0.018). After normalizing the HEF as 100% in each rabbit before CCl4 administration, the deconvoluted curve after CCl4 administration revealed less hepatocyte extraction efficiency with a mean value of 77.7±3.6. There was a significant correlation between the HEF and changes of the ICG R15 by the Pearson correlation coefficient assessment (correlation coefficient = -0.965, p = 0.000).

Conclusion

The Gd-EOB-DTPA HEF could be calculated from deconvolution analysis of aortic and hepatic parenchymal time-intensity curves obtained by dynamic MRI. The Gd-EOB-DTPA HEF was well correlated with changes of the ICG R15, which is the most common parameter used in the quantitative estimation of the hepatic function. The Gd-EOB-DTPA HEF is a direct, noninvasive technique for the quantitative evaluation of liver function. It could be a promising alternative for the determination of noninvasive hepatic function in those patients with liver disease.     

肝硬化患者16层螺旋CT肝内门静脉成像延迟时间的优化

目的探讨优化肝硬化患者16层螺旋CT肝内门静脉成像时间。方法70例正常人与65例肝硬化患者(Child A级30例,Child B级18例,Child C级17例)分别先采用Testbolus技术测定主动脉、门静脉及肝脏实质时间密度曲线,测定主动脉、门静脉及肝实质强化峰值时间;分别记录主动脉、门静脉及肝实质强化峰值时间及CT值。统计处理采用SPSS11.0统计软件包。结果正常人主动脉强化峰值时间与肝硬化患者主动脉强化峰值时间差值之间并无统计学差异(P=0.072),二者主动脉强化峰值之差值间也无统计学差异(P=0.14)。肝硬化患者平均门静脉峰值时间(42.2 s)明显长于正常人(34.5 s,P<0.05)。肝硬化患者门静脉强化峰值(49.9 HU)明显低于正常人(58.0 HU,P<0.05)。正常人与肝硬化患者肝实质强化峰值时间分别为53.9 s和62.5 s(P<0.05),而二者肝实质强化峰值分别为26.6 HU和24.5 HU(P<0.05)。Child B、C级肝硬化患者平均门静脉强化峰值时间(43.8 s)稍长于Child A级肝硬化患者(40.5 s),但二者之间并无统计学差异(P=0.163)。结论在注射速度相同(5 ml/s)的情况下肝硬化患者门静脉强化时间(42.3 s)明显长于正常人(34.4 s),Child B、C级肝硬化患者门静脉强化峰值时间(43.9 s)稍长于Child A级肝硬化患者(40.5 s),但二者之间并无统计学差异。     

64层螺旋CT低剂量扫描诊断外伤性肋骨骨折

目的：探讨64层螺旋CT低剂量扫描诊断外伤性肋骨骨折的价值。方法：随机选择临床疑诊外伤性骨折患者68例,知情同意后分别行胸部CT常规剂量和低剂量扫描,图像行0.625mm薄层重建与曲面重建,由两组医师采用双盲法对图像质量及骨折情况进行分析统计,评价低剂量扫描对于肋骨骨折的诊断价值;同时对两组的CT检查辐射剂量进行对照研究。结果：常规剂量与低剂量扫描方法分别诊断肋骨骨折286处和281处,其诊断符合率为98.25%。两组扫描模式对肋骨显示的图像质量差异无统计学意义（P〉0.05）。常规剂量扫描模式的加权容积CT剂量指数（CTDIvol）为（13.46±1.13）mGy,低剂量扫描模式CTDIvol为（5.42±0.76）mGy,低剂量扫描模式较常规剂量扫描模式的CTDIvol值下降了59.7%。结论：64层螺旋CT低剂量扫描模式可用于外伤性肋骨骨折的临床诊断,具有与常规剂量扫描同等的诊断价值。     

骶骨损伤改良CT扫描法及临床价值

骶骨骨折是脊柱损伤中的常见类型 ,传统X线摄影及CT常规扫描法对无明显移位的轻微骨折检出率较低。我们经过多次实践对常规CT扫描进行了改进 ,现介绍如下。1　方法受检者仰卧位 ,足先进 ,腰部垫高约 10～ 15cm。先扫Scout定位片 ,根据骶骨轴线与水平线夹角大小 ,扫描架向头侧倾     

64层螺旋CT多参数扫描评价急性缺血性脑卒中的研究

目的 探讨多参数CT合理的扫描及后处理技术即PBV在评价缺血性脑卒中的应用价值.方法 72例0～9 h发病患者,分别行CT平扫及CTA检查.使用三维Neuro PBV软件处理CTA图像获得全脑血流灌注图(PBV),以PBV结果指导CT灌注(CTP)扫描.CT检查完毕后6 h内行MR检查.分别计算梗塞灶数目同时测量CTP、PBV与DWI图像梗塞体积.比较多参数CT扫描与MR梗塞灶的数目及梗塞体积.结果 入选患者中,多参数CT与MR发现病灶的数目分别为102、110个;二者之间的Kappa分析结果为0.78.CTP、PBV与MR检测体积配对t检验结果分别为t=7.249,P>0.05;t=11.390,P>0.05.结论 CT多参数扫描较为全面地反映脑缺血病灶的范围及血管情况,在早期诊断脑缺血中具有重要价值.     

胸部CT平扫在诊断贫血中的价值

目的　分析胸部CT平扫图像中心室腔密度CT值与血红蛋白 (Hb)含量间的关系及左心室密度减低与贫血的相关性 ,探讨胸部CT平扫在诊断贫血中的价值。资料与方法　回顾性分析 2 4例贫血患者胸部CT平扫图像 ,与 2 4例非贫血对照组进行比较研究 ,测量其左心室及室间隔CT值 ,结合 72h内临床检查Hb含量及红细胞数 ,进行统计学分析。结果　心室腔CT值与Hb含量及红细胞数间均具有明显正相关性 ,相关系数分别为 0 .6 5 98和0 .5 715 (P值均 <0 .0 1) ;贫血组心室腔CT值低于正常组 ,其差异具有显著统计学意义 (t =4 .2 5 5 ,P =0 .0 0 1,<0 .0 1) ,室隔差值明显高于非贫血组 ,其差异具有统计学意义 (t=2 .90 8,P =0 .0 0 2 ,<0 .0 1) ,贫血组中肉眼不能区分室间隔形态者 (A组 )Hb含量明显高于肉眼可以明确分辨室间隔及左心室形态者 (B组 ) (t =2 .82 2 ,P <0 .0 1)。结论　胸部CT平扫左心室密度减低 ,肉眼可以区分室间隔及左心室形态和密度差均可以大致判断贫血存在与否 ,并可以大致确定贫血者Hb含量的范围     

Rounded Atelectasis. Evaluation With (18)PET Scan

Rounded atelectasis is a well recognized, benign cause of a pulmonary mass. While its radiographic features have been well characterized in the radiologic literature, they are not pathognomonic and patients are commonly biopsied. Positron emission tomography (PET) has become a powerful tool to distinguish between benign and malignant disease in the thorax. We present the CT and PET imaging features of three cases of biopsy proven rounded atelectasis.