64层螺旋CT对使用正常剂量与低剂量造影剂肺动脉CTA的效果分析

目的:探讨64层螺旋CT对使用正常剂量与低剂量造影剂肺动脉CT血管成像(CT angiography,CTA)的效果。方法:选取2020年5月-2022年4月在深圳市宝安区松岗人民医院接受检查的58例疑诊为肺动脉栓塞的患者为研究对象,按照随机数字表法分成对照组(n=34)与研究组(n=24),均使用Siemens 64层螺旋CT自动扫描法,对照组采用常规剂量造影剂法(60~80 mL碘佛醇),研究组则运用低剂量造影剂法(20~30 mL碘佛醇),对比两组CT扫描结果。结果:研究组主肺动脉干、左肺动脉、右肺动脉、左肺静脉干、右肺静脉干强化CT值均低于对照组,但差异不显著(P> 0.05);两组图像噪声比、对比噪声比、信噪比比较差异无统计学意义(P> 0.05);研究组图像的增强质量优秀率高于对照组但差异不显著(P>0.05);研究组不良反应发生率(4.17%)显著低于对照组(23.53%)(P<0.05)。结论:64层螺旋CT使用低剂量造影剂肺动脉CTA成像效果与正常剂量造影剂成像效果相差无几,可满足临床诊断需求,且不良反应少,值得推广。

Imaging diagnosis of colorectal liver metastases

Rapid advances in imaging technology have improved the detection, characterization and staging of colorectal liver metastases. Multi-modality imaging approach is usually the more useful in diagnosis colorectal liver metastases. It is well established that hepatic resection improves the long-term prognosis of many patients with liver metastases. However, incomplete resection does not prolong survival, so knowledge of the exact extent of intra-hepatic disease is crucially important in determining patient management and outcome. The diagnosis of liver metastases relies first and totally on imaging to decide which patients may be surgical candidates. This review will discuss the imaging options and their appropriate indications. Imaging and evaluating of colorectal liver metastases （CRLM） have been performed with contrast-enhanced ultrasound, multidetector computed tomography, magnetic resonance imaging （MRI） with extra-cellular contrast media and liver-specific contrast media MRI, and positron emission tomography/computed tomography. This review

Value of contrast-enhanced ultrasound in diagnosis of focal liver lesions

Objective： By observing the pattern of the focal liver lesions （FLL） in different phases by real time contrast-enhanced ultrasound （CEUS）, compared to enhanced CT, investigate the value of CEUS in diagnosing focal liver lesions. Meth. ods： 35 patients with unconfirmed focal liver lesions were studied by contrast agent SonoVue and Technos DU 8 produced by Esaote company. Results： Among the 14 cases of hepatocellular carcinoma （HCC）, 10 were typical, presented with early artery enhancement and immediate wash-out. The enhancement patterns of 6 livers metastasis were diverse, including peripheral or entire degree enhancement. The wash-out time in malignant tumors was eadier than other focal liver lesions （P 〈 0.05）, appeared as hypoechoic in the portal phase or parenchyma phase. The 6 cases of hemangioma were enhanced centripetally nodular in artery phase and washed out after several minutes. The patterns of different lesions were similar compared to contrast-enhanced CT, without significant statistic differences. Conclusion： The contrast enhanced ultrasound technique can significantly improved the value of diagnosing focal liver lesions.

Ultraviolet/ozone and oxygen plasma treatments for improving the contact of carbon nanotube thin film transistors

Carbon nanotube thin film transistor （CNT-TFF） is an emerging technology for future macroelectronics, such as chemical and biological sensors, optical detectors, and the backplane driving circuits for flat panel displays. The mostly reported fabrication method of CNT-TFT is a lift-off based photolithography process. In such fabrication process, photoresist （PR） residue contaminates the interface of tube-metal contact and deteriorates the device performance. In this paper, ultraviolet ozone （UVO） and oxygen plasma treat- ments were employed to remove the PR contamination. Through our well-designed experiments, the UVO treatment is confirmed an effective way of cleaning contamination at the tube-metal interface, while oxygen plasma treatment is too reactive and hard to control, which is not appropriate for CNT-TFTs. It is determined that 2-6 rain UVO treatment is the preferred window, and the best optimized treatment time is 4 rain, which leads to 15% enhancement of device performance.

Dendrimer-based magnetic resonance imaging agents for brain cancer

Brain cancer is one of the most lethal and difficult-to-treat cancers because of its physical location and biological barriers. The mainstay of brain cancer treatment is surgical resection, which demands precise imaging for tumor localization and delineation. Thanks to advances in bioimaging, brain cancer can be detected earlier and resected more reliably. Magnetic resonance imaging（MRI） is the most common and preferred method to delineate brain cancer, and a contrast agent is often required to enhance imaging contrast.Dendrimers, a special family of synthetic macromolecules,constitute a particularly appealing platform for constructing MRI contrast agents by virtue of their well-defined three-dimensional structure, tunable nanosize and abundant surface terminals, which allow the accommodation of high payloads and numerous functionalities. Tuning the dendrimer size,branching and surface composition in conjunction with conjugation of MRI functionalities and targeting moieties can alter the relaxivity for MRI, overcome the blood-brain barrier and enhance tumor-specific targeting, hence improving the imaging quality and safety profile for precise and accurate imaging of brain tumors. This short review highlights the recent progress, opportunities and challenges in developing dendrimer-based MRI contrast agents for brain tumor imaging.

Radiographic and clinical analysis of cementless acetabular fixation in total hip arthroplasty

Objective： To investigate the factors affecting the fixation, loosening and therapeutic effect of cementless acetabular prosthesis through following up the patients with total hip arthroplasty clinically and radiographically. Methods： From February 1998 to May 1999, 139 patients （148 hips） underwent total hip arthroplasty with cementless acetabular prosthesis in our department. In this study, the clinical therapeutic effect and the anteroposterior radiographs of the pelvis and anteroposterior and lateral radiographs of the hips of 109 patients （116 hips） made before operation, at 1 week operation and annually 3, 6, and 12 months after thereafter were analyzed retrospectively. The clinical therapeutic effects were evaluated with Harris hip score. Radiographs were used to observe the position of prostheses and the bone changes around the implant, and to measure the wearing speed and direction of the acetabular cup. All evaluations were made by an independent examiner who did not participate in the operation. The patients were followed up for 5-6 years. Results- The mean Harris score was 44 points （ range, 10-70 points ） before operation, but it increased to 92.4 points （ range, 80-100 points） at the latest review after operation, which was significantly higher than that before operation （P 〈 0.05 ）. No acetabular component was revised because of infection or aseptic loosening. And no acetabular component migrated. There was no revision of fixed acetabular component because of pelvic osteolysis secondary to polyethylene wear. The mean linear wear rate was 0.15 mm per year. All the acetabular prostheses were classified as stable on the radiographs. Conclusions ： In terms of fixation, total hip arthroplasty with cementlcss acetabular components was successful. Although there is no aseptic loosening and a low incidence of osteolysis at the latest follow-up evaluation, polyethylene wear cannot be avoided and can lead to expansile osteolysis near the cups. This kind of osteolysis usually had no obvious clinical symptoms but it can be diagnosed early on radiographs. So radiographical follow-up for cementless acetabular components is very important.