耐高压注射型PICC导管在CT增强扫描中的应用价值

【摘要】目的：探讨耐高压注射型PICC导管在CT增强扫描中的应用价值。方法：选取行CT增强扫描并已置入耐高压注射型PICC导管和静脉留置针的322例患者，将其中使用耐高压注射型PICC通路行CT增强扫描的242例患者纳入观察组，选择静脉留置针行CT增强扫描的80例患者纳入对照组。结果：观察组护理不良事件的总发生率（4.1%）低于对照组（13.8%），差异有统计学意义（P=0.003）。观察组从进入检查室到开展CT检查耗时、CT检查结束后处理通路耗时、合计耗时分别为（3.31±0.66）min、（4.05±0.76）min、（7.36±1.01）min，对照组分别为（5.56±0.86）min、（7.79±0.68）min、（13.35±1.05）min，两组差异均有统计学意义（P值均＜0.05）。结论：应用耐高压注射型PICC导管作为CT增强扫描注射对比剂的静脉通路，可减少反复穿刺给患者带来的痛苦，降低护理不良事件的发生风险，值得临床推广应用。     

应用高压注射器注射CT对比剂时血管外渗的频率和处理

皮下外渗被认为是对比剂注射的并发症 ,外渗可造成局部皮肤小红斑肿胀和广泛的组织坏死。螺旋ＣＴ的广泛使用 ,高压注射器注射对比剂日渐增多 ,在造影时注射速度快、观察时间短 ,另外年老体弱和肿瘤化疗的患者 ,血管弹性差或有损伤更易造成对比剂外渗。1　材料与方法　　收集 1999年 6月～ 1999年 11月 1732例患者使用高压注射器以 1.0～ 3.5ｍｌ/ｓ速率注射碘对比剂的情况。ＣＴ机为ＥｌｓｃｉｎｔＴｗｉｎ ,静脉造影剂有离子型高渗造影剂 ,6 5 %安其格那芬和非离子低渗造影剂 ,其中 130 1人应用安其格纳芬 ,431人应用优维显。所注对比剂在…     

胃CT检查的口服对比剂对照研究

目的：通过４种对比剂的对照研究，选择胃ＣＴ检查理想口服对比剂。材料与方法：对１００例ＣＴ检查者（正常４５例，异常５５例）进行了４种对比剂（水、脂肪、空气、阳性造影剂）的对照研究。结果：研究表明，阳性对比剂对胃壁和病变的显示不满意，而水和脂类均为胃的理想口服对比剂，前者经济、有效、简便、无副作用，乐于为患者接受。结论：根据我们的长期临床应用和实验经验，水作为胃的口服对比剂，值得临床推广。     

多发伤螺旋CT增强检查中对比剂应用及安全管理

目的探讨多发伤螺旋CT增强检查中碘对比剂应用及安全性管理。方法回顾性分析2009年1月～2010年3月行螺旋CT增强检查的134例多发伤患者,男性106例,女性28例;年龄2～82岁,平均42.5岁。道路交通伤55例,刀刺伤15例,坠落伤39例,砸伤25例。对比剂主要采用欧乃派克(350mgI/ml)、优维显(370mgI/ml)、三代显(350mgI/ml),用量1.5～2ml/kg,注入速度3.0～4.0ml/s。制定多发伤CT增强检查流程,观察检查过程中生命体征及其他不良反应。结果螺旋CT增强扫描新发现血管等损伤59例次;5例注射对比剂时心率、呼吸加快,但血压稳定,129例无明显生命体征改变;未见恶心、呕吐、皮疹等不良反应症状。2例因躁动配合困难,镇静后行螺旋CT增强检查,导致检查时间延长之外,132例在8～10分钟之内顺利完成检查。结论多发伤螺旋CT增强检查有助于发现血管及实质性脏器损伤,以上3种对比剂安全、有效。     

高压快速CT增强中的注意问题

随着现代医学影像技术日新月异的发展，多排螺旋CT的开展利用，高压快速注射对比剂给诊断带来了越来越多的价值。怎样才能使高压快速增强扫描提供更准确更有效的信息呢？现分析如下。     

小剂量对比剂胸部CT增强检查

目的 评价小剂量对比剂在胸部CT增强检查中的可行性.方法 抽取104例胸部CT增强检查,常规剂量与小剂量法进行对比分析.结果 46例小剂量胸部CT增强效果较满意,与常规剂量无显著区别.结论 如无高压注射器,小剂量胸部增强可以作为一种常规增强方法.     

纯牛奶作为口服低密度对比剂在腹部螺旋CT增强扫描中的应用

为防止静脉注射造影剂时引起胃肠道痉挛出现恶心 ,呕吐 ,国内医院常规为空腹状态下行增强CT扫描 ,但因胃肠道空虚状态下的收缩性而产生的“假瘤征” ,影响腹部占位及淋巴结的判断 ,寻找一种合适的口服低密度对比剂 ,使其应用于腹部CT增强扫描 ,产生良好的胃肠道充盈 ,提高对腹部病变诊断及分期的准确率。1　材料和方法选择 2 0 0 0 0 4～ 2 0 0 1 0 7的 40例CT平扫诊断为腹部肿瘤的患者 ,年龄 2 9～ 76岁 ,平均 47岁。其中男 2 9例 ,女 11例。增强扫描前 40～ 60min口服 40 0～ 60 0ml纯牛奶 ,在扫描前 1min再口服 2 0 0～ 40 0ml纯年奶…     

静脉内对比剂增强CT检查时等渗与低渗碘对比剂对肾功能影响的研究

目的明确接受静脉内对比剂增强CT检查的高危病人，应用等渗对比剂相对于低渗对比剂对肾功能[血浆肌酐（SCr）与肾小球滤过率（GFR）]的影响。方法研究符合HIPAA要求，由医学伦理委员会批准并有知情同意书。117例（男83例，女34例；年龄18～86岁，平均64．3岁）肾功能低下的病人接受了对比剂增强CT检查，使用等渗碘克沙醇（n=61）或低渗的碘普罗胺（n=56）。CT检查后3d内检测SCr的增高与GFR的下降，并在30d与90d后随访，记录病人的结果。SCr增高标准：≥0．5mg／dL（44．2umol／L，25％）或≥1．0mg／dL（88．4umol／L，50％）；GFR下降标准：≥5mL／min。     

心脏CT检查时对比剂注射方案的优化

多层螺旋CT（MSCT）的间世拓展了CT在心脏检查中的应用范围,新一代MSCT尤其是64层以上的螺旋CT,因其良好的时间分辨力、空间分辨力及密度分辨力,得到了临床医生的广泛认可。冠状动脉CT血管成像（CCTA）对冠状动脉疾病的诊断,其阴性预测值可达到98％～99％,与传统冠状动脉造影相比,MSCT对冠心病的筛查、斑块及组成成分的观察、斑块危险度的预测、     

Multi-slice CT contrast enhancement regimens

Historically, the development of progressively faster Computed Tomography (CT) technology has dictated a recurrent need to re-examine intravenous contrast agent enhancement regimens. The most recently introduced development, the very fast, multi-slice helical/spiral systems, have raised the same issue yet again. It is possible, exploiting the technology to its maximum potential as regards speed, to perform an examination many times faster (depending on the number of detector rings from 4 to 64) even than with earlier single slice spiral instruments. In order to optimise image quality, such maximal speed gains will not usually be sought but, nevertheless, imaging time will generally be substantially reduced. It is natural that the question of a possible need to modify contrast agent enhancement protocols designed for an earlier generation of slower machines should again be considered. Using as a basis known contrast agent pharmacokinetics and results of modelling techniques, the matter is tackled in this paper.     

Multi-detector row CT of the head and neck: comparison of different volumes of contrast material with and without a saline chaser

Introduction The aim of this study was to determine the effect of different volumes of contrast material with and without a saline chaser on tissue enhancement in multidetector row CT (MDCT) of the head and neck.Methods In a blind prospective fashion, 120 patients were randomized into the following four groups: group 1, 80 ml contrast material administered at a flow rate of 2.0 ml/s; group 2, 80 ml followed by 40 ml saline at 2.0 ml/s; group 3, 60 ml at 1.5 ml/s; and group 4, 60 ml followed by 30 ml saline at 1.5 ml/s. The attenuation values of the carotid artery, internal jugular vein, and muscle were measured at an interval of 1.5 s in each patient. The degree of perivenous artifacts was subjectively assessed.Results Mean attenuation values in the carotid artery and internal jugular vein were significantly higher in groups 1 and 2 than in groups 3 and 4. The width of the diagnostic window (both carotid and jugular enhancement >150 HU) were significantly longer in groups 1 and 2 than in groups 3 and 4. The addition of a saline chaser did not result in improved vascular enhancement or a wider diagnostic window, but reduced perivenous artifacts, compared with using contrast material alone.Conclusion Reduction of contrast material from 80 to 60 ml results in insufficient enhancement of neck vessels. In addition, the benefit of a saline chaser technique is not obvious except for its ability to reduce perivenous artifacts.     

胸内髓外造血组织增生的CT诊断

目的:探讨胸内髓外造血组织增生(EMH)的CT表现,提高其正确诊断率。方法:回顾性分析5例EMH的胸部CT资料,分析病变的特点。结果:胸内EMH的CT表现为两侧脊柱旁沟、肋骨旁对称或不对称分布的稍高密度软组织肿块影,病变边缘光滑,密度均匀,相邻椎体骨小梁增粗,肋骨膨大、髓腔增宽,皮质变薄。增强扫描明显均匀强化。结论:胸内EMH具有特征性的CT表现,结合病史可作出正确诊断。     

Multidetector CT (64 Slices) of the liver: examination techniques

Sixty-four-row MDCT, although developed primarily for cardiac imaging, has the potential to have a great impact on liver imaging as well. Liver-imaging protocols with sub-millimeter collimation improve longitudinal spatial resolution, making the acquired dataset a real isotropic volume perfectly designed for optimal three-dimensional rendering and accurate organ and lesion volumetry. The 64-row detector array offers a wide volumetric coverage (up to 40 mm), suitable not only for shortening scanning time and improving spatial resolution, but also for including a large volume per single rotation, particularly useful for accurate CT perfusion studies. In order to take full benefit from the enormous performance offered by new 64-row MDCT scanners, imaging protocols need to be redesigned. Due to the extremely short scanning window, contrast agent injection should be performed at high flow rate and followed by saline bolus chaser; the use of highly concentrated contrast media might be useful. Timing should be accurately calculated either by a test bolus or, better, by using an automatic bolus-detection technique. Radiation exposure is kept under control, using automatic device-modulating dose delivery according to the patient’s anatomy. Finally, the evaluation of acquired volumetric datasets needs the extensive use of a dedicated workstation, with software with sophisticated rendering capabilities.     

A molecular CT blood pool contrast agent

RATIONALE AND OBJECTIVES: A molecular-based computed tomographic (CT) contrast agent with prolonged vascular residence time is needed for vascular and tumor imaging. No particulate agents have reached clinical practice due to nonspecific macrophage activation. The authors' objective was to synthesize a water-soluble macromolecular agent. MATERIALS AND METHODS: Dysprosium-DTPA-dextran was synthesized through activation of the hydroxyl units of dextran PM40 with allylbromine and subsequent reaction with amino ethanethiol to produce amino-terminated leashes. These leashes were then coupled to DTPA by means of the mixed anhydride method. Complexation of dysprosium by DTPA-dextran was achieved in an acidic solution of 0.2 M dysprosium chloride. One rabbit with a VX2 tumor was imaged with [Dy]DTPA-dextran (0.5 mL, 3.1 g, 1.15 mmol of dysprosium per kilogram). Transaxial scans were acquired through the liver and tumor for 45 minutes. A second healthy rabbit was imaged with Optiray-320 (6.0 mL, 5.0 mmol of iodine per kilogram) at 1-minute intervals for 10 minutes and again at 20 minutes. RESULTS: Each dextran PM40 molecule (diameter, 8.8 nm) contained 95 [Dy]DTPA groups, increasing its average molecular weight from 40,500 to 101,537 g/mol. The baseline-corrected inferior vena cava (IVC) enhancement for [Dy]DTPA-dextran decreased, with an 8-minute half-time during the first 15 minutes followed by a nearly zero slope for the rest of the observation period. The IVC remained brighter than liver throughout the observation period. The solid portion of the tumor was enhanced by 5-10 CT numbers, rendering areas of necrosis more apparent. The baseline-corrected IVC curve for Optiray-320 also demonstrated two phases, with half-times of 2.5 and 45 minutes. The IVC became less dense than liver within 5-8 minutes. CONCLUSION: [Dy]DTPA-dextran is water soluble and can be synthesized without intermolecular cross-linking to carry a high load of dysprosium. It provides blood pool enhancement characteristics with a long intravascular dwell time.     

Meta-analysis: serum creatinine changes following contrast enhanced CT imaging

Purpose

Contrast induced nephropathy (CIN) is defined as a decrease in renal function following administration of contrast media. The aim of this meta-analysis was to asses the overall risk of CIN, chronic loss of kidney function and the need for renal replacement therapy (RRT) after intravenous contrast enhanced CT-scan. Secondly, we aimed to identify subgroups at increased risk for CIN.

Materials and methods

A literature search in Pubmed, Medline, Embase and Cochrane databases was performed. Data extraction was carried out independently by two reviewers. Meta-analysis and meta-regression were performed using an exact likelihood approach.

Results

Forty studies evaluating the incidence of CIN after CT were included. The pooled incidence of CIN was 6.4% (95% CI 5.0–8.1). The risk of RRT after CIN was low, 0.06% (95% CI 0.01–0.4). The decline in renal function persisted in 1.1% of patients (95% CI 0.6–2.1%). Patients with chronic kidney disease (odds ratio 2.26, p < 0.001) or diabetes mellitus (odds ratio 3.10, p < 0.001) were at increased risk for the development of CIN.

Conclusion

CIN occurred in 6% of patients after contrast enhanced CT. In 1% of all patients undergoing contrast enhanced CT the decline in renal function persisted.     

Multidetector CT angiography using a dual-head power injector and bolus tracking for the diagnosis of aortic aneurysms at reduced contrast material dosage

RATIONALE AND OBJECTIVES: To establish the utility of multidetector computed tomography (CT) angiography using dual-head power injector in the diagnosis of aortic diseases. METHODS: In a prospective study, 151 patients with aortic diseases were examined by four-detector CT. Scanning was performed using bolus tracking technique. In all patients nonionic contrast was injected at the rate of 1.5 mL/sec. One hundred one patients were examined with dual-head power injector using 0.6 mL/kg contrast flushed by 30 mL of saline solution (group D). Fifty patients were examined with single-head power injector using 1.0 mL/kg contrast only (group S). We evaluated CT values at descending aorta, upper abdominal aorta, abdominal aortic bifurcation, and bilateral common femoral arteries. RESULTS: There were no statistically significant difference of CT values at descending aorta, upper abdominal aorta, abdominal aortic bifurcation, and right common femoral artery. At left common femoral artery, CT values in group D were higher than those in group S with statistically difference (P < .05). In group D, about 40% dose reduction was achieved without reducing image qualities. CONCLUSION: Multidetector CT angiography using dual-head power injector was valuable for the contrast dose reduction of aortic diseases.     

Evaluation of the nephrotoxicity of iodixanol in patients with predisposing factors to contrast medium induced nephropathy referred for contrast enhanced computed tomography

To determine the risk of developing contrast induced nephropathy (CIN) in intermediate-risk patients receiving iodixanol, an iso-osmolar, dimeric non-ionic contrast agent, for CT in a clinical setting.     

Medial axis reformation: a new visualization method for CT angiography

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate a new method (medial axis reformation [MAR]) for visualizing three-dimensional vascular data at electron-beam computed tomographic (CT) angiography. MATERIALS AND METHODS: MAR was performed automatically with a personal computer-based workstation. After the region of interest was edited, voxels were divided into groups according to their path lengths. Centroids of groups were connected to form the medial axis. Then, the medial axis was refined with multiscale medial response. Bifurcations were also detected and refined. Finally, curved sections were generated through the branches and laid out onto a single image by using a splitting method. The authors performed MAR during electron-beam CT angiography of coronary arteries, common carotid arteries, and iliac arteries. RESULTS: MAR displayed curved sections of branched vessels on one image, cut through the axis of vessels to show the vessel diameter objectively, and allowed the viewing direction to be altered arbitrarily. CONCLUSION: Results of preliminary applications demonstrate that MAR is a valuable new visualization method for CT angiography.     

Effect of contrast injection protocol with dose tailored to patient weight and fixed injection duration on aortic and hepatic enhancement at multidetector-row helical CT

The aim of this study was to investigate the effect of a contrast material injection protocol with dose and injection rate of contrast material tailored to patient weight (dose tailored to patient weight and fixed injection duration). Hepatic helical CT was performed in 92 patients with chronic liver damage with a dose of 1.4 ml (518 mgI) at a rate of 0.056 ml/s per kilogram body weight of Iopamidol 370. Attenuation values of liver and aorta were measured for calculation of maximum aortic and hepatic enhancement, time to maximum hepatic enhancement, and end of hepatic arterial phase. Correlation coefficients between the injection rate and the four parameters were r=0.008, 0.057, 0.167, and 0.036, and there were no statistically significant correlations between the injection rates and the four parameters. In our injection protocol, uniform temporal scan window may be achieved and the injection rate can be reduced in lighter patients without reducing the degree of enhancement in the aorta and the liver.