DDoS Attack Detection in Cloud Computing Based on Ensemble Feature Selection and Deep Learning

Intrusion Detection System(IDS)in the cloud Computing(CC)environment has received paramount interest over the last few years.Among the latest approaches,Deep Learning(DL)-based IDS methods allow the discovery of attacks with the highest performance.In the CC environment,Distributed Denial of Service(DDoS)attacks are widespread.The cloud services will be rendered unavailable to legitimate end-users as a consequence of the overwhelming network traffic,resulting in financial losses.Although various researchers have proposed many detection techniques,there are possible obstacles in terms of detection performance due to the use of insignificant traffic features.Therefore,in this paper,a hybrid deep learning mode based on hybridizing Convolutional Neural Network(CNN)with Long-Short-Term Memory(LSTM)is used due to its robustness and efficiency in detecting normal and attack traffic.Besides,the ensemble feature selection,mutualization aggregation between Particle Swarm Optimizer(PSO),Grey Wolf Optimizer(PSO),Krill Hird(KH),andWhale Optimization Algorithm(WOA),is used to select the most important features that would influence the detection performance in detecting DDoS attack in CC.A benchmark dataset proposed by the Canadian Institute of Cybersecurity(CIC),called CICIDS 2017 is used to evaluate the proposed IDS.The results revealed that the proposed IDS outperforms the state-of-the-art IDSs,as it achieved 97.9%,98.3%,97.9%,98.1%,respectively.As a result,the proposed IDS achieves the requirements of getting high security,automatic,efficient,and self-decision detection of DDoS attacks.

Clinical and computed tomography features of adult abdominopelvic desmoplastic small round cell tumor

To investigate the clinical and computed tomography(CT)features of desmoplastic small round cell tumor(DSRCT),we retrospectively analyzed the clinical presentations,treatment and outcome,as well as CT manifestations of four cases of DSRCT confirmed by surgery and pathology.The CT manifestations of DSRCT were as follows:(1)multiple soft-tissue masses or diffuse peritoneal thickening in the abdomen and pelvis,with the dominant mass usually located in the pelvic cavity;(2)masses without an apparent organbased primary site;(3)mild to moderate homogeneous or heterogeneous enhancement in solid area on enhanced CT;and(4)secondary manifestations,such as ascites,hepatic metastases,lymphadenopathy,hydronephrosis and hydroureter.The prognosis and overall survival rates were generally poor.Commonly used treatment strategies including aggressive tumor resection,polychemotherapy,and radiotherapy,showed various therapeutic effects.CT of DSRCT shows characteristic features that are helpful in diagnosis.Early discovery and complete resection,coupled with postoperative adjuvant chemotherapy,are important for prognosis of DSRCT.Whole abdominopelvic rather than locoregional radiotherapy is more effective for unresectable DSRCT.

Prediction of microvascular invasion in solitary hepatocellular carcinoma≤5 cm based on computed tomography radiomics

BACKGROUND Liver cancer is one of the most common malignant tumors,and ranks as the fourth leading cause of cancer death worldwide.Microvascular invasion(MVI)is considered one of the most important factors for recurrence and poor prognosis of liver cancer.Thus,accurately identifying MVI before surgery is of great importance in making treatment strategies and predicting the prognosis of patients with hepatocellular carcinoma(HCC).Radiomics as an emerging field,aims to utilize artificial intelligence software to develop methods that may contribute to cancer diagnosis,treatment improvement and evaluation,and better prediction.AIM To investigate the predictive value of computed tomography radiomics for MVI in solitary HCC≤5 cm.METHODS A total of 185 HCC patients,including 122 MVI negative and 63 MVI positive patients,were retrospectively analyzed.All patients were randomly assigned to the training group(n=124)and validation group(n=61).A total of 1351 radiomic features were extracted based on three-dimensional images.The diagnostic performance of the radiomics model was verified in the validation group,and the Delong test was applied to compare the radiomics and MVIrelated imaging features(two-trait predictor of venous invasion and radiogenomic invasion).RESULTS A total of ten radiomics features were finally obtained after screening 1531 features.According to the weighting coefficient that corresponded to the features,the radiomics score(RS)calculation formula was obtained,and the RS score of each patient was calculated.The radiomics model exhibited a better correction and identification ability in the training and validation groups[area under the curve:0.72(95%confidence interval:0.58-0.86)and 0.74(95%confidence interval:0.66-0.83),respectively].Its prediction performance was significantly higher than that of the image features(P<0.05).CONCLUSION Computed tomography radiomics has certain predictive value for MVI in solitary HCC≤5 cm,and the predictive ability is higher than that of image features.

Deep Learning Approach for COVID-19 Detection in Computed Tomography Images

With the rapid spread of the coronavirus disease 2019(COVID-19)worldwide,the establishment of an accurate and fast process to diagnose the disease is important.The routine real-time reverse transcription-polymerase chain reaction(rRT-PCR)test that is currently used does not provide such high accuracy or speed in the screening process.Among the good choices for an accurate and fast test to screen COVID-19 are deep learning techniques.In this study,a new convolutional neural network(CNN)framework for COVID-19 detection using computed tomography(CT)images is proposed.The EfficientNet architecture is applied as the backbone structure of the proposed network,in which feature maps with different scales are extracted from the input CT scan images.In addition,atrous convolution at different rates is applied to these multi-scale feature maps to generate denser features,which facilitates in obtaining COVID-19 findings in CT scan images.The proposed framework is also evaluated in this study using a public CT dataset containing 2482 CT scan images from patients of both classes(i.e.,COVID-19 and non-COVID-19).To augment the dataset using additional training examples,adversarial examples generation is performed.The proposed system validates its superiority over the state-of-the-art methods with values exceeding 99.10%in terms of several metrics,such as accuracy,precision,recall,and F1.The proposed system also exhibits good robustness,when it is trained using a small portion of data(20%),with an accuracy of 96.16%.

Same day yttrium-90 radioembolization with single photon emission computed tomography/computed tomography: An opportunity to improve care during the COVID-19 pandemic and beyond

BACKGROUND The coronavirus disease 2019(COVID-19)pandemic has made it more challenging for patients to undergo yttrium-90(Y-90)radioembolization(RE).Same day Y-90 RE provides an opportunity to minimize logistical challenges and infection risk associated with COVID-19,thus improving patient access.AIM To describe the use of same day Y-90 RE with routine single photon emission computed tomography/computed tomography(SPECT/CT)in order to optimize therapy.METHODS All patients were selected for Y-90 RE through a multidisciplinary tumor board,and were screened and tested for COVID-19 infection per institutional protocol.A same day procedure was developed,consisting of angiography,imaging,and Y-90 resin particle delivery.Routine SPECT/CT after technetium-99m macroaggregated albumin(Tc-99m MAA)administration was performed for assessment of arterial supply,personalized dosimetry,and extrahepatic activity.Post-treatment Y-90 bremsstrahlung SPECT/CT was performed for confirmation of particle delivery,by utilization of energy windowing to limit signal from previously administered Tc-99m MAA particles.RESULTS A total of 14 patients underwent same day Y-90 RE between March and June 2020.Mean lung shunt fraction was 6.13%(range 3.5%-13.1%).Y-90 RE was performed for a single lesion in 7 patients,while the remaining 7 patients had treatment of multifocal lesions.The largest lesion measured 8.3 cm.All patients tolerated the procedure well and were discharged the same day.CONCLUSION Same day Y-90 RE with resin-based microspheres is feasible,and provides an opportunity to mitigate infection risk and logistical challenges associated with the COVID-19 pandemic and beyond.We recommend consideration of SPECT/CT,especially among patients with complex malignancies,for the potential to improve outcomes and eligibility of patients to undergo same day Y-90 RE.

A Hybrid Algorithm Based on PSO and GA for Feature Selection

One of the main problems of machine learning and data mining is to develop a basic model with a few features,to reduce the algorithms involved in classification’s computational complexity.In this paper,the collection of features has an essential importance in the classification process to be able minimize computational time,which decreases data size and increases the precision and effectiveness of specific machine learning activities.Due to its superiority to conventional optimization methods,several metaheuristics have been used to resolve FS issues.This is why hybrid metaheuristics help increase the search and convergence rate of the critical algorithms.A modern hybrid selection algorithm combining the two algorithms;the genetic algorithm(GA)and the Particle Swarm Optimization(PSO)to enhance search capabilities is developed in this paper.The efficacy of our proposed method is illustrated in a series of simulation phases,using the UCI learning array as a benchmark dataset.

Advances in computed tomography and magnetic resonance imaging of hepatocellular carcinoma

Hepatocellular carcinoma(HCC)is the most common primary liver cancer.Imaging is important for establishing a diagnosis of HCC and early diagnosis is imperative as several potentially curative treatments are available when HCC is small.Hepatocarcinogenesis occurs in a stepwise manner on a background of chronic liver disease or cirrhosis wherein multiple genes are altered resulting in a range of cirrhosisassociated nodules.This progression is related to increased cellularity,neovascularity and size of the nodule.An understanding of the stepwise progression may aid in early diagnosis.Dynamic and multiphase contrast-enhanced computed tomography and magnetic resonance imaging still form the cornerstone in the diagnosis of HCC.An overview of the current diagnostic standards of HCC in accordance to the more common practicing guidelines and their differences will be reviewed.Ancillary features contribute to diagnostic confidence and has been incorporated into the more recent Liver Imaging Reporting and Data System.The use of hepatocyte-specific contrast agents is increasing and gradually changing the standard of diagnosis of HCC;the most significant benefit being the lack of uptake in the hepatocyte phase in the earlier stages of HCC progression.An outline of supplementary techniques in the imaging of HCC will also be reviewed.

秸秆还田下土壤孔隙演化及其对溶质穿透特征的影响机理分析

为揭示秸秆粉碎还田后,不同腐解进程下土壤孔隙演化及其对水分和溶质穿透特征的影响机理,设置不同秸秆还田量(0、5、10、15 t/hm^(2))和还田时间(0、30、60 d)处理,采用CT断层扫描技术,视觉量化了土壤孔隙结构特征演变,并基于溶质穿透试验,分析了水分-溶质迁移优先流规律。结果表明,秸秆还田引起土壤孔隙/喉道特征变化,抑制水分-溶质迁移过程,田间持水率和土壤含水率上升,溶质穿透变慢,优先流现象减少,土壤水肥有效持留;随秸秆腐解至60 d,孔隙/喉道特征改变,优先流开始发育,但土壤水肥持留能力增强。秸秆还田5、10、15 t/hm^(2)初期,和CK组相比大孔隙体积占比分别减少7%、14%、50%,连通孔隙减少11%、39%、66%,表层含水率增加1%、3%、6%。腐解60 d后,和0 d相比大孔隙体积占比分别增加331%、200%、357%,连通孔隙增加33%、84%、195%,表层含水率增加6%、5%、5%,完全穿透试样所需溶质减少55%、76%、67%。基于Green-Ampt模型和指数衰减模型估算了不同秸秆初始投入量在不同腐解时间下的导水特征,发现饱和导水率在秸秆还田后减小,且随秸秆腐解增大。研究可为控制大孔隙流和无效灌溉提供依据,进一步为秸秆科学还田提供实践指导。

基于机器学习的妊娠期糖尿病智能预测系统设计与实现

为帮助有效识别患有妊娠期糖尿病的孕妇,提前干预治疗,降低其潜在风险,设计并开发了妊娠期糖尿病智能预测系统。首先,在对比10种机器学习模型的基础上对临床数据集进行数据归一化和特征筛选,减少模型计算复杂度和一些使模型不稳定的特征;其次,使用Stacking算法对10种不同的机器学习模型进行集成,分别搭建2个集成模型Stacking1和Stacking2,比较集成模型的性能;最后,基于PyQt5设计妊娠期糖尿病智能预测系统,预测孕妇患妊娠期糖尿病的风险,并给出建议。结果表明:使用10个机器学习模型以及2个集成模型对GDM进行预测,发现GBDT的预测结果高于其他机器学习模型,集成模型Stacking2将多个异质学习器相结合表现出较高的准确性和可靠性,且评价指标Accuracy、Precision、Recall、AUC分别为0.900 9、0.901 2、0.900 7、0.900 7,均高于同类模型。智能预测系统能有效预测妊娠期糖尿病的风险,能够及早发现易患病人群,并提供妊娠期糖尿病的科普知识,从而加强对易患病人群的健康管理,降低妊娠期糖尿病发生的风险。

菌阴活动性肺结核的多层螺旋CT影像学特征及诊断模型构建

目的 分析菌阴活动性肺结核的多层螺旋CT(MSCT)影像学特征,并构建诊断模型。方法 选择2020年1月~2023年1月本院收治的肺部疾病患者1016例,按照临床诊断分为菌阴肺结核组(n=478)、非结核肺病组(n=538,其中肺癌200例、肺炎338例),均行MSCT检查,分析两组MSCT影像学特征,以Logistic回归分析明确菌阴活动性肺结核的诊断相关征象,构建菌阴活动性肺结核诊断模型,以ROC曲线下面积评估模型诊断效能。结果 两组间的树芽征、小叶中心结节、空洞、钙化、分叶征等MSCT征象差异有统计学意义(P<0.05)。Logistic回归分析结果显示树芽征、小叶中心结节、空洞是菌阴活动性肺结核的独立危险因素(P<0.05)。根据Logistic回归获得联合诊断模型方程式:Log(P)=-1.256+1.455×树芽征+0.982×小叶中心结节+1.023×空洞,该模型曲线下面积为0.825,诊断敏感度、特异性分别为93.94%、70.97%。结论 以MSCT影像学特征构建的菌阴活动性肺结核诊断模型具有较高诊断价值,可为临床诊疗菌阴活动性肺结核提供可靠依据。

Features of primary pancreatic lymphoma:A bi-institutional review with an emphasis on typical and atypical imaging features

BACKGROUND Primary pancreatic lymphoma(PPL)is a rare neoplasm.Being able to distinguish it from other pancreatic malignancies such as pancreatic ductal adenocarcinoma(PDAC)is important for appropriate management.Unlike PDAC,PPL is highly sensitive to chemotherapy and usually does not require surgery.Therefore,being able to identify PPL preoperatively will not only direct physicians towards the correct avenue of treatment,it will also avoid unnecessary surgical intervention.AIM To evaluate the typical and atypical multi-phasic computed tomography(CT)imaging features of PPL.METHODS A retrospective review was conducted of the clinical,radiological,and pathological records of all subjects with pathologically proven PPL who presented to our institutions between January 2000 and December 2020.Institutional review board approval was obtained for this investigation.The collected data were analyzed for subject demographics,clinical presentation,laboratory values,CT imaging features,and the treatment received.Presence of all CT imaging findings including size,site,morphology and imaging characteristics of PPL such as the presence or absence of nodal,vascular and ductal involvement in these subjects were recorded.Only those subjects who had a pre-treatment multiphasic CT of the abdomen were included in the study.RESULTS Twenty-nine cases of PPL were diagnosed between January 2000 and December 2020(mean age 66 years;13 males/16 females).All twenty-nine subjects were symptomatic but only 4 of the 29 subjects(14%)had B symptoms.Obstructive jaundice occurred in 24%of subjects.Elevated lactate dehydrogenase was seen in 81%of cases,whereas elevated cancer antigen 19-9 levels were present in only 10%of cases for which levels were recorded.The vast majority(90%)of tumors involved the pancreatic head and uncinate process.Mean tumor size was 7.8 cm(range,4.0-13.8 cm).PPL presented homogenous hypoenhancement on CT in 72%of cases.Small volume peripancreatic lymphadenopathy was seen in 28%of subjects.Tumors demonstrated encasement of superior mesenteric vessels in 69%of cases but vascular stenosis or occlusion only manifested in 5 out of the twentynine individuals(17%).Mild pancreatic duct dilatation was also infrequent and seen in only 17%of cases,whereas common bile duct(CBD)dilation was seen in 41%of subjects.Necrosis occurred in 10%of cases.Size did not impact the prevalence of pancreatic and CBD dilation,necrosis,or mesenteric root infiltration(P=0.525,P=0.294,P=0.543,and P=0.097,respectively).Pancreatic atrophy was not present in any of the subjects.CONCLUSION PPL is an uncommon diagnosis best made preoperatively to avoid unnecessary surgery and ensure adequate treatment.In addition to the typical CT findings of PPL,such as homogeneous hypoenhancement,absence of vascular stenosis and occlusion despite encasement,and peripancreatic lymphadenopathy,this study highlighted many less typical findings,including small volume necrosis and pancreatic and bile duct dilation.

儿童结缔组织病相关间质性肺病临床特点及治疗转归分析

目的 分析儿童结缔组织病相关间质性肺病(CTD-ILD)临床资料,提高对儿童CTD-ILD的认识。方法 回顾性分析2012年1月至2021年12月53例CTD-ILD住院患儿临床资料,包括临床表现、胸部HRCT、肺功能、治疗及转归等。结果 53例CTD-ILD患儿中,23例诊断CTD的同时经HRCT评估诊断为ILD,4例以ILD起病,26例CTD诊断ILD的时间跨度为15天~7年余。呼吸系统常见的症状为咳嗽(47.2%)、气促(28.3%)和啰音(26.4%),但有21例患儿无呼吸道症状,依据HRCT诊断ILD。胸部HRCT显示斑片影(64.2%)、条絮/条片影(55.6%)、条索影(37.7%)、网格/蜂窝影(24.5%)、囊状低密度影(24.5%)、磨玻璃影(22.6%)等。肺功能异常以弥散功能下降(46.5%)、限制性通气功能障碍(39.5%)和小气道功能障碍(32.6%)为主。经糖皮质激素、免疫抑制剂、生物制剂治疗后,48例患儿临床症状有好转。胸部HRCT:20例有好转,21例无明显变化,6例进展;肺功能:17例有好转,11例无明显变化,3例进展,8例正常。结论 儿童CTD-ILD临床症状缺乏特异性,胸部HRCT及肺功能检查有助于早期发现肺部病变,需积极完善检查并定期随访;治疗方案主要是糖皮质激素联合免疫抑制剂和/或生物制剂,但生物制剂在儿童中的应用需进一步研究。

^(18)F-FDG PET/CT代谢参数联合临床病理特征对晚期结直肠癌患者KRAS基因突变的评估价值

目的探讨^(18)F-氟代脱氧葡萄糖(^(18)F-FDG)PET/CT代谢参数联合临床病理特征对晚期结直肠癌患者鼠类肉瘤病毒癌基因(KRAS)基因突变的评估价值。方法回顾性分析64例晚期结直肠癌患者的临床资料。所有患者在治疗前均接受^(18)F-FDG PET/CT检查。分析最大标准化摄取值(SUV_(max))、不同阈值下的代谢肿瘤体积(MTV)和病变总糖酵解(TLG)、临床病理特征与患者KRAS基因突变状态之间的关系。通过多因素Logistic回归模型分析与患者KRAS基因突变相关的因素。采用受试者工作特征曲线分析^(18)F-FDG PET/CT代谢参数、临床病理特征及二者联合评估患者KRAS基因突变的效能。基于^(18)F-FDG PET/CT代谢参数和临床病理特征构建列线图模型。结果单因素和多因素Logistic回归分析结果显示,SUV_(max)≥19.55、MTV50%≥7.95、肿瘤组织中/高分化与患者KRAS基因突变有关。SUV_(max)、MTV50%和肿瘤组织分化程度评估患者KRAS基因突变的曲线下面积(AUC)分别为0.653、0.625和0.621,三者联合评估的AUC为0.800,均高于单个指标的AUC(P<0.05)。基于SUV_(max)、MTV50%和肿瘤组织分化程度构建的列线图模型的一致性指数为0.800,校准曲线与参考线基本拟合。结论^(18)F-FDG PET/CT的代谢参数SUV_(max)、MTV50%与晚期结直肠癌患者KRAS基因突变密切相关,联合肿瘤组织分化程度所构建的列线图模型对患者KRAS基因突变具有较高的评估价值。

基于CAD-RADS的高危斑块特征联合CT-FFR对冠状动脉临界病变预后的预测价值

目的:研究基于冠状动脉疾病报告和数据系统(coronary artery disease-reporting and data system,CAD-RADS)的高危斑块特征联合CT血流储备分数(fractional flow reserve derived from CT,CT-FFR)对冠状动脉病临界病变患者预后的临床应用价值。方法:在CAD-RADS结构式报告基础上,前瞻性研究冠状动脉CT血管造影(coronary artery CT angiography,CCTA)影像资料和临床资料,共301例临界病变患者纳入研究,影像观察指标包括CAD-RADS≥3、钙化积分≥100、斑块易损性特征、高危斑块、长病变、CT-FFR≤0.8,观察指标的组合包括CAD-RADS≥3 V、CAD-RADS≥3 V且CT-FFR≤0.8。研究终点为预后不良,包括主要不良心血管事件(major adverse cardiovascular events,MACE)及计划外有创冠状动脉造影(invasive coronary angiography,ICA)、血运重建手术,研究样本分为预后良好组和预后不良组。通过统计不同组间数据的差异,评价CAD-RADS高危斑块联合CT-FFR对临界病变患者预后的临床价值。结果:年龄、钙化积分、CAD-RADS类别、斑块易损性特征、高危斑块、长病变、CT-FFR在预后良好组和预后不良组间的差异有统计学意义(P<0.05);CAD-RADS类别、高危斑块、CT-FFR是冠状动脉临界病变预后的独立预测因子(P<0.05);CT-FFR≤0.8在CAD-RADS≥3组、钙化积分≥100组、不同斑块易损性特征组、高危斑块组、长病变组中发生率差异均有统计学意义(均P<0.05);观察指标组合(CAD-RADS≥3 V且CT-FFR≤0.8)预测预后不良的特异性、准确性和阳性预测值分别为97.2%、85.7%、88.7%,AUC为0.795(95%CI:0.731~0.858)。结论:基于CAD-RADS的高危斑块特征联合CT-FFR能有效预测MACE及计划外ICA、血运重建手术,指导临床针对性干预与治疗。

鼻咽癌颅底骨转移瘤SPECT/CT影像特征变化及诊断价值分析

目的分析单光子发射计算机体层成像CT(SPECT/CT)在诊断鼻咽癌(NPC)颅底骨转移瘤中的应用价值。方法选取2019年1月-2021年6月期间于我院拟接受手术治疗的60例NPC患者,全部患者术前均接受SPECT/CT及核磁共振成像(MRI)检查,以随访作为“金标准”,对比分析患者SPECT/CT、MRI检查影像特征以及SPECT/CT、MRI检查对NPC颅底骨转移的诊断结果和诊断效能。结果经SPECT/CT检查评估NPC的准确度、灵敏度、特异度、阳性预测值、阴性预测值分别为81.66%、86.04%、70.58%、88.09%、66.66%,经MRI检查准确度、灵敏度、特异度、阳性预测值、阴性预测值分别为63.33%、67.44%、52.94%、78.37%、39.13%(P<0.05);经SPECT/CT检查评估NPC颅底骨转移的准确度、灵敏度、特异度、阳性预测值、阴性预测值分别为76.66%、73.60%、81.81%、87.50%、64.28%,经MRI检查准确度、灵敏度、特异度、阳性预测值、阴性预测值分别为56.66%、50.00%、68.18%、73.07%、44.11%(P<0.05)。结论SPECT/CT在NPC颅底骨转移瘤中有较高的诊断价值,临床在放射治疗前参照SPECT/CT影像特征,可全面掌握病灶情况,提高诊断的准确率。

HRCT在不同级别肺黏液表皮样癌中的鉴别诊断价值

目的:探讨高分辨率CT(HRCT)在不同级别肺黏液表皮样癌(PMEC)中的鉴别诊断价值。方法:回顾性分析2010年1月—2022年12月南京市胸科医院收治的30例PMEC患者的资料。患者术前均行HRCT平扫和增强检查,基于术后病理分为低级别组(n=16)、高级别组(n=14),分析比较两组病灶位置、大小、是否钙化、强化程度及伴随征象等影像特征。结果:PMEC患者年龄多为50~60岁,其中女性患者多见,占67%,肿块最大径及左右肺分布在低级别组和高级别组中差异无统计学意义(P>0.05)。30例PMEC患者8例(8/30)为周围型,22例为中央型(22/30),且左右两肺的分布无差别;肿块边界清晰,无分叶共19例,其中低级别组PMEC共12例;PEMC中密度均匀者13例,多见于低级别PMEC;平扫CT值50~60 HU,增强扫描呈轻度强化15例,且中-重度强化多见于高级别PMEC;伴瘤内钙化者共11例,其中低级别组6例,高级别5例。淋巴结转移、胸腔积液、胸膜牵拉凹陷在两组间差异无统计学意义(P>0.05)。结论:PMEC可见于老年患者,常表现为管腔内或中央型肿块,伴钙化或阻塞性改变;相对于高级别PMEC,低级别PMEC多表现为边缘光滑、密度均匀、轻度强化的结节。

Endoscopic classification and pathological features of primary intestinal lymphangiectasia

BACKGROUND The appearance of the intestinal mucosa during endoscopy varies among patients with primary intestinal lymphangiectasia(PIL).AIM To classify the endoscopic features of the intestinal mucosa in PIL under endoscopy,combine the patients’imaging and pathological characteristics of the patients,and explain their causes.METHODS We retrospectively analyzed the endoscopic images of 123 patients with PIL who were treated at the hospital between January 1,2007 and December 31,2018.We compared and analyzed all endoscopic images,classified them into four types according to the endoscopic features of the intestinal mucosa,and analyzed the post-lymphographic computed tomography(PLCT)and pathological characteristics of each type.RESULTS According to the endoscopic features of PIL in 123 patients observed during endoscopy,they were classified into four types:nodular-type,granular-type,vesicular-type,and edematous-type.PLCT showed diffuse thickening of the small intestinal wall,and no contrast agent was seen in the small intestinal wall and mesentery in the patients with nodular and granular types.Contrast agent was scattered in the small intestinal wall and mesentery in the patients with vesicular and edematous types.Analysis of the small intestinal mucosal pathology revealed that nodular-type and granulartype lymphangiectasia involved the small intestine mucosa in four layers,whereas ectasia of the vesicular-and edematous-type lymphatic vessels largely involved the lamina propria mucosae,submucosae,and muscular layers.CONCLUSION Endoscopic classification,combined with the patients’clinical manifestations and pathological examination results,is significant and very useful to clinicians when scoping patients with suspected PIL.

Clinical and imaging features of desmoid tumors of the extremities

BACKGROUND Desmoid fibroma is a rare soft tissue tumor originating from the aponeurosis,fascia,and muscle,and it is also known as aponeurotic fibroma,invasive fibroma,or ligamentous fibroma.AIM To investigate the clinical and imaging features of desmoid tumors of the extremities.METHODS Thirteen patients with desmoid fibroma of the extremities admitted to our hospital from October 2016 to March 2021 were included.All patients underwent computed tomography(CT),magnetic resonance imaging(MRI),and pathological examination of the lesion.Data on the diameter and distribution of the lesion,the relationship between the lesion morphology and surrounding structures,MRI and CT findings,and pathological features were statistically analyzed.RESULTS The lesion diameter ranged from 1.7 to 8.9 cm,with an average of 5.35±2.39 cm.All lesions were located in the deep muscular space,with the left and right forearm each accounting for 23.08%of cases.Among the 13 patients with desmoid fibroma of the extremities,the lesions were"patchy"in 1 case,irregular in 10,and quasi-round in 2.The boundary between the lesion and surrounding soft tissue was blurred in 10 cases,and the focus infiltrated along the tissue space and invaded the adjacent structures.Furthermore,the edge of the lesion showed"beard-like"infiltration in 2 cases;bone resorption and damage were found in 8,and bending of the bone was present in 2;the boundary of the focus was clear in 1.According to the MRI examination,the lesions were larger than 5 cm(61.54%),round or fusiform in shape(84.62%),had an unclear boundary(76.92%),showed uniform signal(69.23%),inhomogeneous enhancement(84.62%),and"root"or"claw"infiltration(69.23%).Neurovascular tract invasion was present in 30.77%of cases.CT examination showed that the desmoid tumors had slightly a lower density(69.23%),higher enhancement(61.54%),and unclear boundary(84.62%);a CT value<50 Hu was present in 53.85%of lesions,and the enhancement was uneven in 53.85%of cases.Microscopically,fibroblasts and myofibroblasts were arranged in strands and bundles,without obvious atypia but with occasional karyotyping;cells were surrounded by collagen tissue.There were disparities in the proportion of collagen tissue in different regions,with abundant collagen tissue and few tumor cells in some areas,similar to the structure of aponeuroses or ligaments,and tumor cells invading the surrounding tissues.CONCLUSION Desmoid tumors of the extremities have certain imaging features on CT and MRI.The two imaging techniques can be combined to improve the diagnostic accuracy,achieve a comprehensive diagnosis of the disease in the clinical practice,and reduce the risk of missed diagnosis or misdiagnosis.In addition,their use can ensure timely diagnosis and treatment.

增材制造多孔结构的冲击性能研究

多孔结构由于具有较好的比强度、能量吸收等特点,已经广泛运用于航空航天装置、生物医疗器械等方面。而多孔结构的力学性能在很大程度上取决于其结构单元的变形机制,因此充分了解多孔结构在受到冲击载荷过程中的结构演化是至关重要的。本文利用3DVoronoi技术设计了80%与90%孔隙率的十四面体(Octa)结构,通过选择性激光熔化(SLM)成形技术制备了两种孔隙率下铝合金多孔结构的样品,并进行了落锤冲击试验,以探究在受到冲击载荷下不同孔隙率多孔结构的能量吸收情况,在有限元模拟中通过X射线透射电脑断层成像(XCT)重建多孔结构的几何模型,以探索多孔结构的实际变形机制和孔隙破裂的机理。研究结果表明,多孔结构的能量吸收随孔隙率的增加而减小,高孔隙率的多孔结构更容易在较弱的位置形成多个局部密实区,同时单胞壁的弯曲与屈服一般是发生在孔隙的坍塌期间,而变形往往是通过形成几个狭窄的塌陷带进行传播。本文对Octa结构受到冲击载荷的变形机理有了全新的认识,这对多孔结构的抗冲击设计和能量吸收评估具有重要意义。