Morphological imaging and CT histogram analysis to differentiate pancreatic neuroendocrine tumor grade 3 from neuroendocrine carcinoma

PurposeTo compare morphological imaging features and CT texture histogram parameters between grade 3 pancreatic neuroendocrine tumors (G3-NET) and neuroendocrine carcinomas (NEC).Materials and methodsPatients with pathologically proven G3-NET and NEC, according to the 2017 World Health Organization classification who had CT and MRI examinations between 2006-2017 were retrospectively included. CT and MRI examinations were reviewed by two radiologists in consensus and analyzed with respect to tumor size, enhancement patterns, hemorrhagic content, liver metastases and lymphadenopathies. Texture histogram analysis of tumors was performed on arterial and portal phase CT images. images. Morphological imaging features and CT texture histogram parameters of G3-NETs and NECs were compared.ResultsThirty-seven patients (21 men, 16 women; mean age, 56 ± 13 [SD] years [range: 28-82 years]) with 37 tumors (mean diameter, 60 ± 46 [SD] mm) were included (CT available for all, MRI for 16/37, 43%). Twenty-three patients (23/37; 62%) had NEC and 14 patients (14/37; 38%) had G3-NET. NECs were larger than G3-NETs (mean, 70 ± 51 [SD] mm [range: 18 - 196 mm] vs. 42 ± 24 [SD] mm [range: 8 - 94 mm], respectively; P = 0.039), with more tumor necrosis (75% vs. 33%, respectively; P = 0.030) and lower attenuation on precontrast (30 ± 4 [SD] HU [range: 25-39 HU] vs. 37 ± 6 [SD] [range: 25-45 HU], respectively; P = 0.002) and on portal venous phase CT images (75 ± 18 [SD] HU [range: 43 - 108 HU] vs. 92 ± 19 [SD] HU [range: 46 - 117 HU], respectively; P = 0.014). Hemorrhagic content on MRI was only observed in NEC (P = 0.007). The mean ADC value was lower in NEC ([1.1 ± 0.1 (SD)] × 10⁻³ mm²/s [range: (0.91 - 1.3) × 10⁻³ mm²/s] vs. [1.4 ± 0.2 (SD)] × 10⁻³ mm²/s [range: (1.1 - 1.6) × 10⁻³ mm²/s]; P = 0.005). CT histogram analysis showed that NEC were more heterogeneous on portal venous phase images (Entropy-0: 4.7 ± 0.2 [SD] [range: 4.2-5.1] vs. 4.5 ± 0.4 [SD] [range: 3.7-4.9]; P = 0.023).ConclusionPancreatic NECs are larger, more frequently hypoattenuating and more heterogeneous with hemorrhagic content than G3-NET on CT and MRI.     

Classification and cyclic fatigue evaluation of new kinematics for endodontic instruments

This study evaluated the effect of new motions of the motor TriAuto ZX2 on the cyclic fatigue of endodontic instruments. Vortex Blue 35.06 instruments were divided into four groups (n = 10) and tested for fatigue in a curved artificial canal (90° and 2 mm radius) using the following motions: continuous rotation (CR), Optimum Torque Reverse (OTR) set at 180° and the Optimum Glide Path (OGP), which was tested at 90° and 240°. The time to fracture (TTF) and the lengths of the fractured fragments were recorded. The mean TTF was significantly different among the groups (anova , P < 0.05): OGP 90° (213.39 ± 27.45), OTR 180° (121.24 ± 17.03), OGP 240° (45.24 ± 5.61) and CR (8.43 ± 1.27). Weibull analysis confirmed the shortest life expectancy for CR and the longest survival for OGP at 90°. The resistance to fatigue was affected by motions and pre‐set angles. The proprietary movements that are currently available for endodontic instruments were classified according to their kinematics.     

Shaping ability of the M4 handpiece and Safety Hedstrom Files in simulated root canals

The aim of this study was to assess the shaping ability of the M4 reciprocating handpiece and Safety Hedstrom files in simulated canals. A total of 40 simulated canals of various angles and positions of curvature were prepared with an M4 handpiece using Safety Hedstrom files oriented with the ground, flattened surface towards the inner aspect of the curve. A standard regimen was adopted throughout. Pre- and post-operative longitudinal images of the canals were taken with a video camera and stored and manipulated in a computer with image analysis software. The presence of canal aberrations and the amount and location of resin material removed as a result of preparation were determined from composite images of superimposed pre- and post-operative views. Preparation time varied significantly (P<0.001) between the canal types; overall, 20° canals were prepared more quickly than 40° canals. Zips and elbows were observed in 16 out of the 40 canals with most (11) being created in 40° specimens. Ledges were found in 19 canals and perforations in only 1. There were no significant differences between canal shapes for these aberrations. Excessive removal of material from the inner aspect of the canal at the curve to create a danger zone was found in 20 canals, but only in those with 40° curves. Significant differences in total canal width between the canal types were seen at the zips (P<0.05), elbows (P<0.05) and danger zones (P<0.001). Transportation at the danger zones varied significantly (P<0.001) between canal types. Under the conditions of this study, the M4 handpiece and Safety Hedstrom files created hour-glass preparations in a substantial proportion of canals. In reality, the Safety Hedstrom file with its one flattened surface was ineffective at reducing removal of material along the inner aspect of canal curves in severely curved specimens and clearly has the potential to create strip perforations in teeth.     

医学影像存储的色彩模式和文件格式的比较

本文介绍了不同的影像色彩模式和影像文件常见存储格式的特点及其在应用上的优缺点，分析了影像色彩模式、文件存储的格式与影像质量、用途的关系。     

两种后牙根管预备方法的临床效果比较

目的 :评估 2种后牙根管预备方法的临床效果。方法 :采用机用镍钛扩大锉 (ProFile)和手用不锈钢扩大锉 (K file)扩大后牙根管 ,并对 2组病例术后疼痛以及充填情况加以比较。结果 :发现机用镍钛扩大锉扩大后牙根管 ,具有去除根管感染物质彻底 ,根管形态保持良好 ,速度快 ,术后疼痛率较低的优点 ,但易出现断针。而手用不锈钢扩大锉扩大后牙根管速度较慢 ,术后疼痛率略高 ,但不易出现断针 ,操作上容易掌握。结论 :2种后牙根管方法都有优缺点 ,可结合起来使用。     

Automated Recognition of Lateral from PA Chest Radiographs: Saving Seconds in a PACS Environment

Images acquired in a two-view digital chest examination are frequently not electronically distinguishable. As a result the lateral and posterioanterio (PA) images are often improperly positioned on a PACS work station. A series of 1998 chest radiographs (999 lateral, 999 PA or AP) were used to develop a neural network classifier. The images were down-sampled to 16 × 16 matrices, and a feed-forward neural network was trained and tested using the leave-one-out method. Using five nodes in the hidden layer, the neural network correctly identified 987 of the 999 test cases (98.8%) (average of six runs). The simple architecture and speed of this technique suggests that it would be a useful addition to PACS work station software. The accumulated time saved by correctly positioning the lateral and PA chest images on the work station monitors in accordance with each radiologists hanging protocols was estimated to be about 1 week of radiologist time per year.     

基于PACS的MRI影像多媒体教学与报告系统的研究

目的：开发基于医院影像归档和通讯系统（picture archiving and communication system，PACS）环境的MRI（磁共振显像）影像多媒体教学与报告系统。方法：医院PACS系统符合DICOM3.0标准，采用1000M光纤主干网，100M交换到桌面；在临床医生浏览工作站安装多媒体教学系统，在诊断工作站安装教学系统与报告系统；科学内容按部位分类，以树枝模式管理。教学字资料来源于具有一定权威的教科书、专及期刊。图像资料来源于各部位经病理及临床证实的病例，直接从PACS系统提取，经标注说明后，以件形式存放于PACS图像服务器硬盘。结果：MRI辅助影响教学系统能够实时调阅最合适病种的MRI征象、临床特点、病理、鉴别诊断、典型图像及注释、正常断面解剖等，供教学、诊断和报告参考。结论：PACS环境下MRI辅助影像学系统，能满足临床医生和低年资影像诊断医生对MRI影像知识进一步继续医学教育的需求，能为影像诊断医生提供教学及科研工具，提高MR室工作质量和工作效率。     

Transition from Film to Electronic Media in the First-Year Medical School Gross Anatomy Lab

For the benefit of the first-year gross anatomy students, we digitized and published on a Web site images that had been collected over a 30-year period. We provided a CD-ROM (compact disk, read-only media) containing the image set in higher quality format to students and faculty. We supplemented basic images with hot topics such as CT angiography, virtual colonography, computer-aided diagnosis, and 3D post-processing. Full motion video and moving JPEG (Joint Photo Expert Group) animations were integrated into the atlas. On the post course questionnaire medical students reported that the images on CD-ROM were helpful during the course and for review prior to examinations. Faculty and medical students used the CD-ROM for problem-based learning sections and facilitator training. The images were clear and easily projected during review sessions and were useful for the small group sessions, where they served as examples of normal anatomy.     

PACS诊断工作站匹配小型DSA在介入治疗中的应用

目的 探讨PACS诊断工作站与小型DSA匹配在介入治疗中的应用价值。方法 PACS诊断工作站通过视频采集一转换方式采集岛津公司的WHA-50N／S小型DSA的PH-DSA方式获得的视频图像，使用DIGOM 3．0国际标准。对采用该系统检查治疗的67例图像资料进行分析，评价该工作站的使用效能。结果 将PACS诊断工作站与小型DSA相接后，将原来的PH-DSA视频图像转变为10～25帧／S的数字DSA图像，可上传输至PACS，达到资料共享。提高了图像后处理的功能。应用该系统获得的数字图像能够保持原设备的清晰程度，无明显失真，可以显示1～2mm的3～4级血管。结论采用小型DSA与PACS诊断工作站相匹配，可以为介入治疗的开展提供可靠的保障。     

医学影像存储与传输系统存储模式的探讨

目的 探讨医学影像存储与传输系统中的存储介质、结构，提高图像存储容量及调用速度。方法PACS采用三级（在线、近线、离线）存储结构；利用硬盘、多服务器磁盘阵列、磁带库等作为存储介质，支持影像数据的短期存储管理和长期存储管理；采用冗余存储技术和镜像存储方式；提供定时自动备份和数字迁移功能。结果成功地实现了医学图像在网络中的存储、备份及调用。结论PACS中的三级存储模式大大提高了图像的存储容量及调用速度，提高了工作效率。