激电法鉴别“干断层”试验

在地壳上,有一半左右的断层不含水或含水微量,成为“干断层”。这类断层用地质分析或电阻率法较难区分,成为基岩区找水的难题。本文简要阐述了激电法鉴别“干断层”的机理、技术方法、资料解释及效果。

地震剖面中走滑断层旋向判断模型——以塔东阿拉干北断层为例

地震剖面解释中尚无走滑断层旋向的直接判别标志,本文提出了一个在地震剖面解释中直接判断走滑断层旋向的模型。该模型假定断层作用前既存的某个地层厚度有变化,则垂直或斜交地层厚度变化方向的走滑断层必定在穿过断层的地震剖面中两盘地层厚度不等。确定了地层厚度变化方向,又测定了剖面中两盘地层厚度,则走滑断层的旋向就可以唯一地确定下来。穿过塔里木盆地东部阿拉干北右行走滑断层的地震剖面资料证实了这一模型的适用性。

黄芩苷对家兔视网膜炎性水肿厚度影响的研究

目的:研究黄芩苷对炎性视网膜水肿的影响。方法:建立炎性视网膜水肿的动物模型,用OCT测量黄芩苷对炎性视网膜水肿过程中视网膜厚度的影响。新西兰白兔15只(30个视网膜)随机分为5组,建立炎性视网膜水肿模型后,组1注射黄芩苷溶液(160mg/L,20mL/kg),2次/d;组2使用黄芩苷溶液(40mg/L,20mL/kg),2次/d;组3使用黄芩苷溶液(10mg/L,20mL/kg),2次/d;组4使用球后注射曲安奈德,给药剂量为20mg(0.5mL)。组5为对照组,被耳缘静脉注射等量BSS。分别在建模后1,2,4,6,10,14,21d用光学相干断层扫描(opitical coherence tomograph,OCT)测量视网膜的平均厚度。结果:与炎性对照组相比,黄芩苷治疗组视网膜厚度明显降低,两组差异具有统计学意义(P<0.01);黄芩苷组与激素组比较,48h内有差别,但差异不显著(t=5.85,4.3;0.001<P<0.01);2d后,两组差异性消失(t<2.447,P>0.05),从统计学角度看两者无差别。结论:黄芩苷能够有效抑制炎性视网膜细胞外水肿,并且与皮质激素具有相同的药效,并且无明显毒副作用。

两种非甾体抗炎药对白内障术后黄斑水肿影响的对比研究

目的比较0.1%溴芬酸钠水合物滴眼液和普拉洛芬滴眼液对白内障超声乳化术后黄斑水肿的影响。方法采用前瞻性临床随机对照试验。将行白内障超声乳化吸除联合人工晶状体植入术的年龄相关性白内障患者随机分为两组,每组118只眼。A组:术前2 d和术后4周应用0.1%溴芬酸钠水合物滴眼液,联合术后2周应用妥布霉素地塞米松滴眼液;B组:术前2 d和术后4周应用普拉洛芬滴眼液,联合术后2周应用妥布霉素地塞米松滴眼液。分别在术前2 d内,术后1 d、1、4、12周测定黄斑中心亚区域平均厚度(CSMT),并计算术后黄斑水肿发生率。结果术前、术后1 d、1周、12周A组与B组CSMT比较,差异均无统计学意义(P>0.05);术后4周A组CSMT为(251.57±6.814)μm,低于B组的(254.40±12.004)μm,差异有统计学意义(P<0.05);术后1 d、1、4、12个月试验组黄斑水肿发生率分别为0、0、0.85%、0.85%,对照组分别为0、0.85%、1.69%、1.69%,术后各时间点两组黄斑水肿发生率比较,差异均无统计学意义(P>0.05)。结论白内障超声乳化术前和术后应用0.1%溴芬酸钠水合物滴眼液或普拉洛芬滴眼液,术后黄斑水肿发生率均较低,前者比后者可能会更大程度地抑制术后黄斑中心亚区域增厚。

频域-OCT在观察高眼压症视网膜神经纤维层及神经节细胞复合体中的应用

目的使用频域相干光断层扫描(SD-OCT)观察高眼压症患者视盘形态学参数、视网膜神经纤维层(RNFL)及黄斑区神经节细胞复合体(GCC)的表现。方法选取52例(96只眼)高眼压患者,按照眼压高低分为两组,与20例(40只眼)正常人进行SD-OCT检查,测量视盘形态学参数、整体平均RNFL厚度(RNFL-Avg)、上方平均RNFL厚度(RNFL-Sup)、下方平均RNFL厚度(RNFL-Inf)、整体平均GCC的厚度(GCC-Avg)、上方平均GCC厚度(GCC-Sup)、下方平均GCC厚度(GCC-Inf),比较两组高眼压症患者与正常对照组之间的差异,并分析高眼压症组RNFL与GCC的相关性。结果两组高眼压症患者与正常对照组比较,视盘各形态学参数(P>0.05)、RNFLAvg(P=0.9017)、RNFL-Sup(P=0.9659)、RNFL-Inf(P=0.7465)、GCC-Avg(P=0.3498)、GCC-Sup(P=0.4203)、GCC-Inf(P=0.3071)均无显著的统计学差异。而RNFL与GCC在整体、上方及下方的厚度均呈明显的正相关(r=0.5631 P=0.001;r=0.5122 P=0.005;r=0.5459 P=0.002)。结论 SD-OCT是一种比较敏感的能够观察到视网膜结构改变的检查方法,对青光眼的早期诊断具有重要的作用。高眼压症患者在眼压明显高于正常的情况下,并无RNFL及GCC的改变,对于高眼压症应该强调严格随诊。

玻璃体切除联合内界膜翻转覆盖治疗特发性黄斑裂孔的临床疗效观察

目的应用玻璃体切除联合内界膜翻转覆盖法治疗特发性黄斑裂孔(IMH),观察术后黄斑裂孔解剖结构及视力的变化情况。方法选取临床确诊IMH患者31例(31只眼),其中男性8例(8只眼),女性23例(23只眼),患者年龄范围:42~82岁,平均(65.68±8.39)岁,行23G玻璃体切除联合内界膜翻转覆盖及注气术。于术后5 d,2周,1、3、6个月进行随访,所有患眼手术前后行最佳矫正视力(BCVA)、裂隙灯,眼底广角眼底照相,频域相干光断层扫描(SD-OCT)检查。观察手术后患者黄斑裂孔愈合率,手术前后BCVA变化情况,黄斑裂孔的愈合类型,翻转覆盖的内界膜与裂孔的位置关系,椭圆体区缺损直径的变化情况。结果术后黄斑裂孔愈合率为100%。手术前后BCVA有显著性差异(t=8.50,P<0.05),术后视力提高。30例裂孔呈"U"型愈合,1例裂孔呈"V"型愈合。29例内界膜瓣完全贴附于视网膜,2例内界膜未完全贴附视网膜并成桥样附着在裂孔正上方。术后椭圆体缺失直径逐渐减小。结论玻璃体切除联合内界膜瓣翻转覆盖术治疗IMH可以取得较高的解剖学复位率和裂孔愈合率,提高视力患者视力,是治疗IMH一种安全有效的手术方法。

Coherence cube enhancement based on local histogram specification

Coherence analysis is a powerful tool in seismic interpretation for imaging geological discontinuities such as faults and fractures. However, subtle faults or fractures of one stratum are difficult to be distinguished on coherence sections （time slices or profiles） due to interferences from adjacent strata, especially these with strong reflectivity. In this paper, we propose a coherence enhancement method which applies local histogram specification （LHS） techniques to enhance subtle faults or fractures in the coherence cubes. Unlike the traditional histogram specification （HS） algorithm, our method processes 3D coherence data without discretization. This method partitions a coherence cube into many sub-blocks and self-adaptively specifies the target distribution in each block based on the whole distribution of the coherence cube. Furthermore, the neighboring blocks are partially overlapped to reduce the edge effect. Applications to real datasets show that the new method enhances the details of subtle faults and fractures noticeably.

Optical coherence tomography in detection of dysplasia and cancer of the gastrointestinal tract and bilio-pancreatic ductal system

Optical coherence tomography(OCT) is an optical imaging modality that performs high-resolution,cross-sectional,subsurface tomographic imaging of the microstructure of tissues.The physical principle of OCT is similar to that of B-mode ultrasound imaging,except that it uses infrared light waves rather than acoustic waves.The in vivo resolution is 10-25 times better(about 10 μm) than with high-frequency ultrasound imaging,but the depth of penetration is limited to 1-3 mm,depending upon tissue structure,depth of focus of the probe used,and pressure applied to the tissue surface.In the last decade,OCT technology has evolved from an experimental laboratory tool to a new diagnostic imaging modality with a wide spectrum of clinical applications in medical practice,including the gastrointestinal(GI) tract and pancreatic-biliary ductal system.OCT imaging from the GI tract can be done in humans by using narrow-diameter,catheter-based probes that can be inserted through the accessory channel of either a conventional front-view endoscope,for investigating the epithelial structure of the GI tract,or a side-view endoscope,inside a standard transparent ERCP catheter,for investigating the pancreatico-biliary ductal system.Esophagus and the esophago-gastric junction has been the most widely investigated organ so far;more recently,also duodenum,colon and pancreatico-biliary ductal system have been extensively investigated.OCT imaging of the gastro-intestinal wall structure is characterized by a multiple-layer architecture that permits an accurate evaluation of the mucosa,lamina propria,muscularis mucosae,andpart of the submucosa.The technique may be,therefore,used to identify pre-neoplastic conditions of the GI tract,such as Barrett's epithelium and dysplasia,and evaluate the depth of penetration of early-stage neoplastic lesions.OCT imaging of the pancreatic and biliary ductal system could improve the diagnostic accuracy for ductal epithelial changes and the differential diagnosis between neoplastic and non-neoplastic lesions.

Cervical inlet patch-optical coherence tomography imaging and clinical significance

AIM:To demonstrate the feasibility of optical coherence tomography(OCT)imaging in differentiating cervical inlet patch(CIP)from normal esophagus,Barrett'sesophagus(BE),normal stomach and duodenum. METHODS:This study was conducted at the Veterans Affairs Boston Healthcare System(VABHS).Patients undergoing standard esophagogastroduodenoscopy at VABHS,including one patient with CIP,one representative patient with BE and three representative normal subjects were included.White light video endoscopy was performed and endoscopic 3D-OCT images were obtained in each patient using a prototype OCT system.The OCT imaging probe passes through the working channel of the endoscope to enable simultaneous video endoscopy and 3D-OCT examination of the human gastrointestinal(GI)tract.Standard hematoxylin and eosin(H and E)histology was performed on biopsy or endoscopic mucosal resection specimens in order to compare and validate the 3D-OCT data. RESULTS:CIP was observed from a 68-year old male with gastroesophageal reflux disease.The CIP region appeared as a pink circular lesion in the upper esophagus under white light endoscopy.OCT imaging over the CIP region showed columnar epithelium structure,which clearly contrasted the squamous epithelium structure from adjacent normal esophagus.3D-OCT images obtained from other representative patients demonstrated distinctive patterns of the normal esophagus,BE,normal stomach,and normal duodenum bulb.Microstructures,such as squamous epithelium,lamina propria, muscularis mucosa,muscularis propria,esophageal glands,Barrett's glands,gastric mucosa,gastric glands, and intestinal mucosal villi were clearly observed with OCT and matched with H and E histology.These results demonstrated the feasibility of using OCT to evaluate GI tissue morphology in situ and in real-time. CONCLUSION:We demonstrate in situ evaluation of CIP microstructures using 3D-OCT,which may be a useful tool for future diagnosis and follow-up of patients with CIP.

Parallel Spectral-Domain Optical Coherence Tomography for Non-Scattering Object Imaging

The parallel spectral-domain optical coherence tomography（PSDOCT） is described for highspeed optical coherence tomography（OCT） without lateral scanning. In this setup, the self-elimination of auto-correlation（AC） interference algorithm was used for eradicating the AC interference and ghost images. However, when performed in free space OCT, this algorithm still generated a weak DC component. The algorithm was improved by adding the background intensity part to compensate for the mutual interference between object and reference arms. The results demonstrate that the DC component can be eradicated. Compared with conventional QCT and complex Fourier-domain optical coherence to- mography, the advantages of PSDOCT with the improved algorithm in free space are that it has no moving parts to generate consecutive phase shift, the structure of the object can be reconstructed immediately and automatically, and the speed is approximately 16 times faster than those of the other two in the same case.

Vessel healings after stenting with different polymers in STEMI patients

Background Different stems implantation in ST-segmem elevation myocardial infarction （STEMI） patients may influence the long term prognosis by affecting vessel healings after stenting. The aim of this study was to evaluate the vessel healings after implantation of drug elming stems （DES） with biodegradable or durable polymer or of bare-metal stems （BMS） in patients with ache STEMI. Methods This study included 50 patients, who underwem follow up angiogram and optical coherence tomography （OCT） assessment about one year after percutaneous coronary intervemion （PCI） for STEMI. According to the initial stems types, these patients were classified to durable （n = 19） or biodegradable polymer sirolimus-eluting stems （n = 15）, or BMS （n = 16） groups. The conditions of stem struts coverage and malapposi- tion were analyzed with OCT technique. Results A total of 9003 struts were analyzed： 3299, 3202 and 2502 from durable or biodegradable polymer DES, or BMS, respectively. Strut coverage rate （89.0%, 94.9% and 99.3%, respectively）, malapposition presence （1.7%, 0.03% and 0 of struts, respectively） and average intimal thickness over struts （76 ± 12 μm, 161 ± 30 μm and 292 ± 29 μm, respectively） were significantly differem among different stent groups （all P 〈 0.001）. Conclusions Vessel healing status in STEMI patients is superior after implantation of biodegradable polymer DES than durable polymer DES, while both are inferior to BMS.

Research on Characteristics of Focal Rupture of the Zhangbei-Shangyi Earthquake by Means of Deformation Field Obtained by Spaceborne D-INSAR

In the last ten years, the D_InSAR (Differential Interferometric Synthetic Aperture Radar) technique has proved very useful; it has been a new space observation technique with great potential. Investigating seismic focus rupture information using D_InSAR is a scientific issue to which more attention is being paid. In this paper, the basic theory of seismic focus dislocation models is discussed briefly. Based on a map of the interferometric deformation field of the Zhangbei_Shangyi earthquake from Jan.10, 1998, and applying the seismic focus dislocation model within elastic half_space medium; some geometrical and kinematical characteristics of the main seismic fault are deduced. Results were as follows: the seismic break surface of the Zhangbei_Shangyi earthquake is left_slip and thrust fault, striking in SEE_NWW 272°with dip angle 46°; rupture direction is unilateral faulting from SEE to NWW; length of rupture zone is 9km, width is 8km, and depth is 8km, the displacement vector of three directions are 290mm, 560mm and 0mm.

Intraretinal layer segmentation and parameter measurement in optic nerve head region through energy function of spatial-gradient continuity constraint

For the diagnosis of glaucoma,optical coherence tomography(OCT)is a noninvasive imaging technique for the assessment of retinal layers.To accurately segment intraretinal layers in an optic nerve head(ONH)region,we proposed an automatic method for the segmentation of three intraretinal layers in eye OCT scans centered on ONH.The internal limiting membrane,inner segment and outer segment,Bruch’s membrane surfaces under vascular shadows,and interaction of multiple high-reflectivity regions in the OCT image can be accurately segmented through this method.Then,we constructed a novel spatial-gradient continuity constraint,termed spatial-gradient continuity constraint,for the correction of discontinuity between adjacent image segmentation results.In our experiment,we randomly selected 20 B-scans,each annotated three retinal layers by experts.Signed distance errors of?0.80μm obtained through this method are lower than those obtained through the state-of-art method(?1.43μm).Meanwhile,the segmentation results can be used as bases for the diagnosis of glaucoma.

Bilateral Macular Lesions Following Electrical Injury

HIGH-VOLTAGE electrical injuries can result in a variety of ocular complications. Cataract and macular edema are the most common injuries.Other injuries include punctate keratopathy,uveitis,macular hole,subretinal macular haemorrhage,and choroidal atrophy.We report a case that optical coherence tomography （OCT） and multifocal electro- retinogram （mfERG） clearly demonstrated the bilateral macular lesions following electrical injury, while the fundus examination was nearly normal.

Thrombosis of celiacomesenteric trunk:Report of a case

Here we present the case of a 79-year-old woman who complained of acute abdominal pain,vomiting and diarrhoea.Laboratory exams demonstrated a severe metabolic imbalance.Abdominal X-rays showed bowel overdistension and pneumatosis of the stomach wall.Abdominal tomography revealed infarction of the stomach,duodenum and small bowel due to thrombosis of the celiacomesenteric trunk.Exploratory laparotomy revealed ischemia of the liver,spleen infarction and necrosis of the gastro-intestinal tube(from the stomach up to the first third of the transverse colon).No further surgical procedures were performed.The patient died the following day.To our knowledge,this is the first reported case about severe gastro-intestinal ischemia due to thrombosis of the celiacomesenteric trunk,a rare anatomic variation of the gastrointestinal vascularisation.

Spectral Domain Optical Coherence Tomography of Vogt-Koyanagi-Harada Disease: Novel Findings and New Insights into the Pathogenesis

Objective To provide novel spectral domain optical coherence tomography (SD OCT) findings of Vogt-Koyanagi-Harada (VKH) disease as well as new insights into the pathogenesis of this disease. Methods Detailed SD OCT and fluorescein angiography (FA) findings of 18 consecutive VKH patients (11 women and 7 men) from December 2007 to April 2009 who were in acute uveitic stage at presentation were reviewed. All the patients had been followed up for at least 6 months with reevaluation(s) of SD OCT performed in 10 patients. Results Intraretinal cysts were found to be located in various layers of the outer retina. In addition to the photoreceptor layer, they could also be found between the outer plexiform layer and the outer nuclear layer, or spanning the external limiting membrane. On FA, intraretinal cysts could be hypofluorescent, normofluorescent, or hyperfluorescent. Some intraretinal cysts had a characteristic FA pattern, in which a small round hypofluorescent area was surrounded by a ring of hyperfluorescence (donut-shaped dye pooling). Subretinal fibrinoid deposit appeared in acute uveitic stage in two severe VKH patients and seemed to develop from subretinal exudates and evolved into typical subretinal fibrosis. Gradual transfiguration/migration and progressive proliferation/pigmentation of the subretinal fibrinoid deposit/subretinal fibrosis was observed in one patient. Conclusions Intraretinal cysts could form in various layers of the outer retina and may result from extension of choroidal inflammation. Subretinal fibrosis may develop from subretinal exudates in VKH patients and may cause substantial visual impairment.

Optical coherence tomography and Doppler optical coherence tomography in the gastrointestinal tract

Optical coherence tomography(OCT) is a noninvasive,high-resolution,high-potential imaging method that has recently been introduced into medical investigations.A growing number of studies have used this technique in the field of gastroenterology in order to assist classical analyses.Lately,3D-imaging and Doppler capabilities have been developed in different configurations,which make this type of investigation more attractive.This paper reviews the principles and characteristics of OCT and Doppler-OCT in connection with analyses of the detection of normal and pathological structures,and with the possibility to investigate angiogenesis in the gastrointestinal tract.

Optical molecular imaging for detection of Barrett's-associated neoplasia

Recent advancements in the endoscopic imaging of Barrett's esophagus can be used to probe a wide range of optical properties that are altered with neoplastic progression.This review summarizes relevant changes in optical properties as well as imaging approaches that measures those changes.Wide-field imaging approaches include narrow-band imaging that measures changes in light scattering and absorption,and autofluorescence imaging that measure changes in endogenous fluorophores.High-resolution imaging approaches include optical coherence tomography,endocytoscopy,confocal microendoscopy,and high-resolution microendoscopy.These technologies,some coupled with an appropriate contrast agent,can measure differences in glandular morphology,nuclear morphology,or vascular alterations associated with neoplasia.Advances in targeted contrast agents are further discussed.Studies that have explored these technologies are highlighted;as are the advantages and limitations of each.

Identification of the layered morphology of the esophageal wall by optical coherence tomography

AIM： To assess each layer of the optical coherence tomography （OCT） image of the esophageal wall with reference to the histological structure, METHODS： Resected specimens of fresh pig esophagus was used as a model for the esophageal wall. We injected cyanoacrylate adhesive into the specimens to create a marker, and scanned them using a miniature OCT probe. The localization of these markers was assessed in the OCT images. Then we compared the OCT-imaged morphology with the corresponding histological section, guided by the cyanoacrylate adhesive markers. We prepared a second set of experiments using nylon sutures as markers. RESULTS： The OCT image of the esophageal specimen has a clear five-layered morphology. First, it consisted of a relatively less reflective layer; second, a more reflective layer; third, a less reflective layer; fourth, a more reflective layer; and fifth, a less reflective layer. Comparing the OCT images with marked histological sections showed that the first layer corresponded to stratified squamous epithelium; the second to lamina propria; the third to muscularis mucosa; fourth, submucosa; and fifth, muscularis propria with deeper structures of the esophageal wa CONCLUSION： We demonstrated that the OCT image of the normal esophageal wall showed a five- layered morphology, which corresponds to histological esophageal wall components.

Optical coherence tomography in measuring retinal nerve fiber layer thickness in normal subjects and patients with open-angle glaucoma

Objectives To investigate image characteristics and thickness of the retinal nerve fiber layer (RNFL) in normal and glaucomatous eyes using optical coherence tomography (OCT), and analyze the relationship between RNFL thickness and visual field index.Methods Eighty-three normal persons (150 eyes) and 83 patients with primary open angle glaucoma (POAG, 149 eyes) underwent OCT examinations with 3.4 mm diameter circle scan to calculate the RNFL thickness. Statistical analysis was used to compare differences in RNFL thickness in quadrants and means between the normal and glaucomatous groups and the different stages of POAG. Linear correlation and regression analysis were used to show the correlation between RNFL thickness and visual field index of 115 eyes in glaucomatous patients. Reproducibility, sensitivity and specificity of RNFL measurements using OCT were evaluated.Results RNFL thickness measured by OCT in normal subjects was thicker in superior and inferior, less in temporal, and thinnest in nasal quadrants. The curve showed double peaks. RNFL of glaucomatous patients showed local thinning or defect, diffuse thinning, or both. The mean RNFL thicknesses of the normal group in the temporal, superior, nasal and infeior quadrants were 90.1 ± 10.8 lμm, 140.4 ± 10.5μm, 85.2 ± 14.0 μm, and 140.4 + 9.7 μm, respectively with a mean of 114.2 ± 6.0 μm. The numbers for the glaucomatous group were respectively 56.0 ± 31.0 μm, 81.0 ± 36.3 μm, 47.1 ± 27.5 μm, and 73.4 ±38.4 μm for the four quadrants, with a mean of 64.6 ± 28.8 μm. There was a significant difference in RNFL thickness between the normal and glaucomatous groups (P ＜ 0.000), and the three stages (early,developing and late) of glaucornatous groups (P ＜ 0.000). There was a close negative relationship between RNFL thickness and visual field index ( r = - 0.796, P ＜ 0.0001 ). The sensitivity and specificity of RNFL thickness in POAG measured using OCT were 93.3％ and 92.0％, respectively.Conclusions OCT can quantitatively measure RNFL thickness differences between normal persons and glaucomatous patients. RNFL thickness gradually decreases while visual field defect increases with the development of POAG.