Optimal scanning protocols of 64-slice CT angiography in coronary artery stents: An in vitro phantom study

Purpose

The purpose of the study was to investigate the optimal scanning protocol of 64-slice CT angiography for assessment of coronary artery stents based on a phantom study.

Materials and methods

Coronary stents with a diameter of 2.5 mm was implanted in thin plastic tubes with an inner diameter of 3.0 mm to simulate a coronary artery. The tubes were filled with iodinated contrast medium diluted to 178 HU, closed at both ends and positioned in a plastic container filled with vegetable oil (−70 to −100 HU). A series of scans were performed with a 64-slice CT scanner with the following protocols: section thickness: 0.67 mm, 1.0 mm, 1.5 mm, 2.0 mm, pitch value: 0.2, 0.3, 0.5 and reconstruction interval of 50% overlap of the section thickness. 2D axial and multiplanar reformatted images were generated to assess the visibility of stent lumen, while virtual intravascular endoscopy (VIE) was reconstructed to evaluate the artery wall and stent surface.

Results

Our results showed that a scanning protocol of 1.0 mm slice thickness with a pitch of 0.3 produced acceptable images with best demonstration of the intrastent lumen and stent surface with minimal image noise or artifacts. In contrast, submillimeter scans with 0.67 mm resulted in moderate artifacts which affected visualization of the coronary lumen, in addition to the increased noise. When the section thickness increased to 1.5 mm and 2.0 mm, visualization of the artery wall and stent surface was compromised, although the intrastent lumen was still visible.

Conclusion

Our in vitro study suggested that a scanning protocol of 1.0 mm section thickness with pitch of 0.3 is the optimal protocol for evaluation of coronary artery stents as it allows generation of acceptable images with better visualization of stent lumen, stent surface and coronary artery wall.     

Tear Fluid Protein Changes in Dry Eye Syndrome Associated with Rheumatoid Arthritis: A Proteomic Approach

Purpose

Sjögren syndrome (SS) secondary to rheumatoid arthritis (RA) affects lacrimal and salivary glands, and therefore dry eye syndrome (DES) is more prevalent in patients with RA. This study used a proteomic approach to identify potential biomarkers in tear of DES secondary to RA (DES-RA).

Characterization of an artificial valve flow using the numerical dye washout visualization technique: application to the monoleaflet valve with purged flow

Until today, no ideal heart valve prosthesis for the replacement of a diseased natural valve or for use in ventricular assist devices exists. Valves still cause thromboembolic complications originating from thrombus formations in the valve's stagnant zones. Optimization of valve design involves avoiding stagnation zones and zones of high shear stresses. This requires detailed flow field investigations. Usually, the regions which are more prone to thrombus formation can be estimated using a dye washout experiment. The method allows an assessment of regions with a high or low residence time that may in turn predict regions with a corresponding thrombus risk. This successful experimental method was simulated using numerical methods with a combination of the computational fluid dynamics program FLUENT (Fluent Inc., Lebanon, NH, USA) and of the visualization tool AMIRA (TGS Inc., San Diego, CA, USA). The numerical dye washout visualization was applied to four monoleaflet valves with varying valve housing geometries. The results show a significant difference in the washout processes of the examined valves. The dye washout was characterized by a time course of the gray value averaged over a defined region of interest. Finally, these curves were quantified by a half dye time. The half dye time in the best optimized valve was only 0.2753 s. The same time in the original valve was 0.6834 s. This study shows that the proposed numerical method of dye washout visualization can be used as an additional tool of the flow characterization in artificial organs.     

Integrating segmentation methods from the Insight Toolkit into a visualization application

The Insight Toolkit (ITK) initiative from the National Library of Medicine has provided a suite of state-of-the-art segmentation and registration algorithms ideally suited to volume visualization and analysis. A volume visualization application that effectively utilizes these algorithms provides many benefits: it allows access to ITK functionality for non-programmers, it creates a vehicle for sharing and comparing segmentation techniques, and it serves as a visual debugger for algorithm developers. This paper describes the integration of image processing functionalities provided by the ITK into VolView, a visualization application for high performance volume rendering. A free version of this visualization application is publicly available and is available in the online version of this paper. The process for developing ITK plugins for VolView according to the publicly available API is described in detail, and an application of ITK VolView plugins to the segmentation of Abdominal Aortic Aneurysms (AAAs) is presented. The source code of the ITK plugins is also publicly available and it is included in the online version.     

Three-dimensional visualization and quantification of the benzodiazepine receptor population within a living human brain using PET and MRI

Positron emission tomography (PET) in combination with receptor-selective high-affinity radioligands allows the characterization of neuroreceptor distributions in the living human brain. Thus far, the visualization and quantification of receptors with PET have been limited to series of two-dimensional (2D) image planes of the anatomic receptor distribution. The development of high-resolution PET has increased the number of planes to approximately 50, supplying an excessive amount of image information from a single experiment. The inherent limitations of 2D techniques make them insufficient to apprehend and efficiently analyze this cumbersome amount of data. In the present communication we describe procedures to visualize and quantify in three dimensions (3D) the total image information from the compound set of 47 2D planes of a PET experiment using commercially available software. Three-dimensional computer graphic and volume rendering techniques were used to analyze and display the results. For the experimental application the benzodiazepine (BZ) antagonist [^t1C]flumazenil was used as radioligand to visualize the BZ receptor (BZR) population in the brain of a healthy human subject. Three-dimensional images of the radioligand binding receptor population were displayed with regard to volume and form in relation to the corresponding anatomic structures in the brain reconstructed from MR images. The volume-rendering technique allowed the inspection of PET signals representing BZR populations in the interior of the hemisphere as viewed from the medial projection. Thresholding and seeding techniques were used to define volumes and quantities. Using the PET data and volume rendering, the total amount of cerebral BZRs (N_Cerebrum) and the apparent volume they take into account (V^app _BZR, Cerebrum) could be calculated for the first time using an automated procedure. The cerebrum of the healthy subject contained 17.6 nmol of BZRs in a voulume of approximately 1.25 L. The principles and application of the technical development described offer new dimensions to clinical neuroscience and should be practically useful for automated quantitative determination of neuroreceptor number in brain regions of patients with neuropsychiatric disorders and in relation to drug treatment.     

Spatio-temporal display of event-related potential data in three dimensions

Summary A technique for visualizing event-related potential data which preserves both spatial and temporal dimensions is presented. This technique can be implemented by several different types of software and may be useful when spatio-temporal information is of critical importance in a data set. It is especially useful for comparing spatio-temporal differences between experimental conditions.This project was generously supported by a grant from the Olfactory Research Fund. The author wishes to thank Dr. R. Kriz for his suggestions concerning opacity modulation in this visualization technique.     

纳米乳经皮渗透的可视化定量分析研究

目的:考察并分析纳米乳的经皮渗透能力。方法:制备含荧光示踪剂OB的纳米乳并对其粒径大小、分布和形态进行分析;另制备含OB的酊剂、肉豆蔻酸异丙酯(IPM)以及辛酸癸酸聚乙二醇甘油酯/聚甘油脂肪酸酯(Labrasol/Plurol Oleique)溶液作为对照;激光共聚焦显微镜可视化定量分析各种制剂在活体大鼠皮肤的透皮路径及透皮性差异。结果:OB纳米乳平均粒径为65.4nm,粒径分布介于39.9~102.7nm,呈大小不均的球形分布体系;透皮2h后,纳米乳在真皮浅层中的荧光强度分别是酊剂、IPM和Labrasol/Plurol Oleique溶液的1.94、2.68、4.93倍。结论:纳米乳具有良好的透皮性,有望成为新型透皮给药制剂。     

手太阴肺经在虚拟人体上的可视化研究

目的:显示手太阴肺经在虚拟人上的体表循行路线。方法:通过定义腧穴为控制点,并适当插值,合成骨架曲线,实现面绘制,重建经脉管状模型。结果:重建后的经脉模型视觉效果好,并可以显示手太阴肺经循行路线上不同层次的解剖结构。结论:初步实现了手太阴肺经在虚拟人体上的可视化显示,为构筑经络研究平台提供了数据载体。     

Global research production in neonatal abstinence syndrome: A bibliometric analysis

BACKGROUNDRecently, neonatal abstinence syndrome (NAS) emerged as a significant global concern with a dramatic increase in healthcare expenditures. The incidence of the NAS has increased notably in the past decade and emergence as a global public health problem. AIMTo evaluate the development and trend of global NAS research from 1958 to 2019 by bibliometric analysis.METHODSAnalyzed aspects included publication output per year, language, document types, journals, countries/territories, h-index, authors, and top research priorities. The VOSviewer was used to determine the top research priorities, and trends, and to present bibliometric networks concerning various dimensions, such as co-authorship, authors, and countries. RESULTSA total of 1738 articles were retrieved in the Scopus database from 1958 to 2019. It was found that the great majority of the total NAS documents (n = 1295) were original articles followed by reviews (n = 268) and letters (n = 48). The most productive countries in the NAS field were the United States (n = 833), Canada (n = 112), the United Kingdom (n = 111), and Germany (n = 77). Treatment and hospital outcomes in NAS, evidence-based nurse-driven interventions for the care of newborns with NAS, and a systematic reviews and network meta-analysis for therapeutic approaches of NAS were found in recent years (after 2010), compared with terms such as pathophysiology, mechanisms of NAS, and signs and symptoms in the early years.CONCLUSIONTreatment and pediatric outcomes and the effectiveness of pharmacological treatment may be frontiers in the NAS field, and continued efforts from researchers are needed in those topics.