衍射增强成像(DEI)动物实验研究

目的通过动物样品的衍射增强成像(DEI),获得衬度及分辨率,并与常规吸收成像比较,对DEI方法进行分析和评价。方法在北京高能物理研究所同步辐射装置(BSRF)形貌站(4W1A束线)上,取大鼠脏器在摇摆曲线上进行扫描,并与常规吸收像进行比较,通过放大法获得分辨率。结果大鼠的肝脏、肾脏样本的DEI均显示较好的衬度和分辨率,并且扫描位置对图像显示具有较大影响。结论DEI从相位衬度角度进行成像,是一种有望开发运用于临床的先进成像技术。     

衍射增强技术应用于医学成像的实验研究

目的本实验通过各类样品的DEI成像，获得衬度及分辨率，并与常规吸收成像比较，对衍射增强成像（DEI）方法进行分析和评价。方法在北京高能物理研究所同步辐射装置（BSRF）形貌站（4W1A束线）上，取人及动物脏器在摇摆曲线上进行扫描，并与常规吸收像进行比较，通过显微放大法获得分辨率。结果不同组织之间存在不同的衍射增强，DEI均显示较好的衬度和分辨率，图像分辨率达到微米级，并且扫描位置对图像显示具有较大影响。结论DEI从相位衬度角度进行成像，极大地改进了成像质量，理论上来说是安全的，有望运用于临床。     

大鼠肾X线衍射增强成像

目的探讨高衬度成像技术--同步辐射衍射增强成像(DEI)对肾脏成像的可能性.方法在北京同步辐射装置(BSRF)采用X线衍射增强成像法对离体的大鼠肾样品进行成像,成像样品的厚度分别为2 mm和120 μm.成像后的样品进行组织学切片,其结果和DEI结果进行对比分析.结果离体大鼠肾衍射增强成像可清晰显示常规成像方法无法观察到的走向清晰的髓质区直集合管和乳头管,以及常规需经造影处理才可见的小叶间动、静脉,最细可分辨直径为30μm的管道结构.结论同步辐射衍射增强成像法具有早期观察肾脏髓质病变及血管微细病变的潜力,该方法为目前影像学尚不能观察到的生物样品结构的成像提供了一种新的研究手段.     

比较同步辐射衍射增强与同轴技术小鼠肾脏成像

目的 通过评价同步辐射相位衬度成像技术在小鼠肾脏微细结构的成像过程,比较同轴成像技术(IOXI)与衍射增强成像(DEI)的差异,探索相位成像技术的应用价值。方法 在北京同步辐射装置(BSRF)形貌站4W1A和上海光源(SSRF)成像线站BL13W上,分别对小鼠肾脏进行成像,以组织衬度与空间分辨力作为评价指标。结果 肾脏微细结构在IOXI与DEI中均得以显示,尤其是IOXI可显示肾小球。通过显微放大法获得的图像空间分辨力达10 μm。结论 包括IOXI与DEI在内的相位衬度成像技术在软组织及血管结构的显示中均具有较高的应用价值。IOXI由于获得成像信息更多,且光路较为简单、图像可直接获得,在生物医学应用研究中的价值可能更高。     

同步辐射装置(BSRF)上的衍射增强医学成像实验

目的：利用衍射增强成像（DEI）技术成像机制的特异性，进行医学样品的成像研究，并进行分析评价。方法：使用衍射增强成像（DEI）技术对肝、肾样本进行成像，通过显微放大法获得图像分辨率，并对摇摆曲线上的不同位置成像结果进行分析，与病理和常规吸收像图像进行比较。结果：获得的成像具有较高的分辨率、可以显示更多的微细结构，摇摆曲线上的不同位置对成像具有较大的影响。结论：DEI对样品，尤其是弱吸收组织（软组织）显示具有较强的特异性，可望在临床上具有广阔的应用前景。     

64层螺旋CT冠状动脉成像技术及影响图像质量的因素

目的 探讨64层螺旋CT冠状动脉成像质量的影响因素。方法回顾性收集2008年9～11月于我院行64层螺旋CT冠状动脉成像的50例患者的影像资料。由两名医师评价图像质量，两名技师评价扫描协议的制定，共同分析影响冠脉成像质量的因素。结果冠脉成像质量除了和心率有很大关系，与患者呼吸运动、扫描螺距、造影剂用量、峰值时间测定以及扫描协议的关系也非常大。结论在冠脉成像中为了获得满意的图像，必须结合病人的心率、呼吸运动、峰值时间、造影剂的用量，来制定适当的扫描协议。     

循证护理对64层螺旋CT冠状动脉成像效果和患者 负性情绪的影响

目的 探讨循证护理对64层螺旋CT冠状动脉成像效果和患者负性情绪的影响.方法 2015年10月至2016年5月选取行64层螺旋CT冠状动脉成像检查的患者120例,根据抽签法将患者分为观察组及对照组,每组60例.对照组检查期间应用常规性护理,观察组检查期间应用循证护理,对比分析两组患者成像质量及检查舒适度的差异.结果 观察组干预后焦虑自评量表(SAS)及抑郁自评量表(SDS)评分均低于对照组(P<0.05).观察组一次性完成检查率、检查依从率、优质图像率及满意率均高于对照组(P<0.05),而CT扫描造影剂渗漏、造影剂不良反应发生率低于对照组(P<0.05).结论 循证护理能有效减轻64层螺旋CT冠状动脉成像患者焦虑、抑郁情绪,降低检查时CT扫描造影剂渗漏及造影剂不良反应率,提高患者检查时依从性,确保成像质量.     

同步辐射微血管成像技术在动物模型中的应用初探

目的:利用同步辐射光源成像技术,探索并建立有效、直观的活体大鼠脑微血管高分辨率动态成像体系。方法:采用体重为300~350 g的SD大鼠,经颈动脉插管,注入2种不同对比剂(碘或硫酸钡对比剂)进行成像,调整成像参数,实现在体及活体观察处于正常生理状态下的大鼠脑部微血管结构,确立成像所需的实验条件。结果:硫酸钡适用于大鼠在体血管的观察,非离子型碘对比剂可用于大鼠活体实时脑血管成像。通过实验,基本确立了大鼠活体成像所需参数;采用时间减影法可降低背景及骨骼等对图像的影响。结论:非离子型碘对比剂适用于活体大鼠脑部微血管成像。同步辐射光源是研究活体实验动物脑微血管结构的高分辨率成像手段,将为有效进行活体动物脑部微血管结构观察提供新的方法和途径。     

64层螺旋CT冠状动脉成像技术的体模实验

目的 采用心脏动态冠脉体模,对影响64层螺旋CT冠状动脉图像质量的因素进行分析.方法 本研究利用心脏动态冠脉体模,在心律整齐的条件下,改变不同的心率;在心律变化的条件下,改变心率波动的范围,采用不同重组算法、图像重组相位窗,评价64层螺旋CT冠状动脉图像质量.结果 图像质量最佳心率为≤70次/分,心率波动≤10次/分,图像质量在R-R间期的75%左右相位(舒张中期)最好.当心率较快时(≥80次/分),在R-R间期45%左右相位能够获得相对好的图像质量.心率较慢而波动小,冠状动脉成像采用segment(单扇区)重组算法,图像质量比较好;而心率快、波动比较大时,冠状动脉成像采用plus(四扇区)重组算法,图像质量比较好.结论 心率、重组算法和图像重组相位窗是影响多层螺旋CT冠脉成像的主要参数,在应用中应适当运用以上的参数,才能获得优质的图像.     

心脏电-机械耦联与双源CT冠状动脉成像最佳成像时间窗

冠状动脉CT成像已成为检测冠状动脉狭窄的一种有效的无创性手段,图像质量是影响其诊断准确性的重要因素。在整个心动周期内,冠状动脉所有节段都有相当大的变化,运动速度也随着心率加快而加快。目前的多排螺旋CT的时间分辨率仍不能满足获取冠状动脉在心动周期内任一瞬间清晰影像的需求。根据心脏电-机械耦联理论,选择不同心率和心律情况下相对低速的心电时相进行数据采集或图像重建,以减少心脏搏动产生的运动伪影。心脏电-机械耦联与冠状动脉成像最佳成像时间窗的选择对于不同心率、心律下冠状动脉CT成像有着重要意义,应用该理论可进一步提高心脏CT图像质量及诊断冠状动脉狭窄的准确性。     

Computed tomography of amyloid plaques in a mouse model of Alzheimer's disease using diffraction enhanced imaging

Our understanding of early development in Alzheimer's disease (AD) is clouded by the scale at which the disease progresses; amyloid beta (Aβ) plaques, a hallmark feature of AD, are small (~ 50 μm) and low contrast in diagnostic clinical imaging techniques. Diffraction enhanced imaging (DEI), a phase contrast x-ray imaging technique, has greater soft tissue contrast than conventional radiography and generates higher resolution images than magnetic resonance microimaging. Thus, in this proof of principle study, DEI in micro-CT mode was performed on the brains of AD-model mice to determine if DEI can visualize Aβ plaques. Results revealed small nodules in the cortex and hippocampus of the brain. Histology confirmed that the features seen in the DEI images of the brain were Aβ plaques. Several anatomical structures, including hippocampal subregions and white matter tracks, were also observed. Thus, DEI has strong promise in early diagnosis of AD, as well as general studies of the mouse brain.     

同步辐射类同轴技术应用于肾脏成像的实验研究

目的 应用同步辐射光源的相干性,进行肾脏组织的类同轴成像研究,旨在评价相位衬度成像技术在软组织成像方面的意义.方法 在北京同步辐射装置形貌站4W1A束线上,取经过4%甲醛溶液固定后的人体肾脏组织样品,置于类同轴光路的样品架上进行成像,以空间分辨率和组织衬度作为评价标准.结果 在样品与成像板距离Z为150 mm时获得的肾脏成像,具有较高的组织衬度,包括肾小囊在内的结构均能较好显示,通过显微放大法获得的空间分辨率达到30 μm.结论 类同轴技术能较好显示肾脏的微细解剖结构,对于以轻元素为主的脏器成像有较好的应用价值.     

Diffraction-enhanced Synchrotron Imaging of Bovine Ovaries Ex Vivo

ObjectivesThe objective of this study was to test the hypothesis that diffraction-enhanced imaging (DEI), a synchrotron x-ray imaging technique, would provide greater contrast for evaluating bovine ovaries compared with conventional diagnostic ultrasonography.Materials and MethodsBovine ovaries were evaluated ex vivo as follows: fresh without radiographic arterial contrast (n = 2), fresh with contrast (n = 1), preserved in 10% formalin without contrast (n = 2), and preserved with contrast (n = 1). Each ovary was imaged with DEI and subsequently with ultrasonography and histology. The ability to visualize and differentiate preantral and antral follicles, corpora lutea (CL), and cumulus oocyte complexes (COCs) were compared using DEI, ultrasonography, and histology. The diameter of follicles and CL were measured and compared using ultrasonography, DEI, and histology. The diameter of the smallest follicle detected was reported using each of the three imaging methods. The number of antral follicles (antral follicle count ≥2 mm) was compared between ultrasonography and DEI.ResultsDEI enabled the detection of 71% of follicles and 67% of CL that were detected ultrasonographically. However, DEI did not allow the detection of COCs and cell layers of the follicle wall that were visualized histologically. Luteal tissues were not easily distinguished using DEI, and DEI was inferior for differentiating follicles and CL compared with ultrasonography. The mean follicle diameter was similar between DEI (4.00 ± 0.35 mm, fresh with contrast; 9.62 ± 2.43 mm, fresh without contrast) and ultrasonography (3.85 ± 0.28 mm, fresh with contrast; 8.97 ± 2.60 mm, fresh without contrast) (P > .05). However, the mean follicle diameter was greater using both DEI (4.00 ± 0.35 mm) and ultrasonography (3.85 ± 0.28 mm) compared with histology (2.21 ± 0.38 mm; P = .01, fresh ovaries with contrast). The mean CL diameter was similar between DEI (11.64 ± 1.67 mm), ultrasonography (9.34 ± 0.35 mm), and histology (9.59 ± 0.36 mm) (P > .05). The mean diameter of the smallest follicle detected was similar between DEI (3.06 ± 0.45 mm) and ultrasonography (2.95 ± 0.74 mm); both DEI and ultrasonographic measurements were greater than histology (0.39 ± 0.04 mm, P < .0001). The mean antral follicle count was similar between ultrasonography (6.50 ± 0.71 mm, fresh with no contrast; 6.50 ± 2.50 mm, preserved with no contrast) and DEI (4.50 ± 0.50 mm, fresh with no contrast; 6.50 ± 0.50 mm, preserved with no contrast) (P > .05).ConclusionsThe contrast resolution of antral follicles, CL, and COCs in bovine ovaries was inferior using DEI compared with ultrasonography and histology. Alternative synchrotron techniques, such as phase-contrast computed tomography and DEI computed tomography, may prove more effective than DEI for imaging ovaries ex vivo.     

Laser speckle imaging for early detection of microbial colony forming units

In this study, an optical contactless laser speckle imaging technique for the early identification of bacterial colony-forming units was tested. The aim of this work is to compare the laser speckle imaging method for the early assessment of microbial activity with standard visual inspection under white light illumination. In presented research, the growth of Vibrio natriegens bacterial colonies on the solid medium was observed and analyzed. Both – visual examination under white light illumination and laser speckle correlation analysis were performed. Based on various experiments and comparisons with the theoretical Gompertz model, colony radius growth curves were obtained. It was shown that the Gompertz model can be used to describe both types of analysis. A comparison of the two methods shows that laser speckle contrast imaging, combined with signal processing, can detect colony growth earlier than standard CFU counting method under white light illumination.     

Double-clad fiber with a tapered end for confocal endomicroscopy

We present a double-clad fiber coupler (DCFC) for use in confocal endomicroscopy to reduce speckle contrast, increase signal collection while preserving optical sectioning. The DCFC is made by incorporating a double-clad tapered fiber (DCTF) to a fused-tapered DCFC for achromatic transmission (from 1265 nm to 1325 nm) of > 95% illumination light trough the single mode (SM) core and collection of > 40% diffuse light through inner cladding modes. Its potential for confocal endomicroscopy is demonstrated in a spectrally-encoded imaging setup which shows a 3 times reduction in speckle contrast as well as 5.5 × increase in signal collection compared to imaging with a SM fiber.     

Contrast-Enhanced Intravascular Ultrasound Pulse Sequences for Bandwidth-Limited Transducers

We demonstrate two methods for vasa vasorum imaging using contrast-enhanced intravascular ultrasound, which can be performed using commercial catheters. Plaque neovascularization was recognized as an independent marker of coronary artery plaque vulnerability. IVUS-based methods to image the microvessels available to date require high bandwidth (−6 dB relative frequency bandwidth >70%), which are not routinely available commercially. We explored the potential of ultraharmonic imaging and chirp reversal imaging for vasa vasorum imaging. In vitro recordings were performed on a tissue-mimicking phantom using a commercial ultrasound contrast agent and a transducer with a center frequency of 34 MHz and a −6 dB relative bandwidth of 56%. Acoustic peak pressures <500 kPa were used. A tissue-mimicking phantom with channels down to 200 μm in diameter was successfully imaged by the two contrast detection sequences while the smallest channel stayed invisible in conventional intravascular ultrasound images. Ultraharmonic imaging provided the best contrast agent detection.     

心肌声学造影视频法与射频法定量分析方法比较研究

目的　比较超声组织定征视频法与射频法在心肌声学造影定量分析中的应用价值。方法　 8只开胸犬 ,经静脉滴注全氟显进行谐波触发显像 ,分别采用DFY型超声图像定量分析诊断仪和声学密度定量 (AD)技术获得心肌声学造影感兴趣区回声强度 (EI)和背向散射积分 (IBS)值 ,并绘制时间 强度曲线 (TIC)。结果　心肌缺血后 ,峰值回声强度 (PEI)、峰值背向散射积分值 (PIBS)降低 ,P值均 <0 .0 5 ;而达PEI及PIBS所需时间 (PT)延长 ,P值均 <0 .0 1。冠脉闭塞后 ,PEI及PIBS显著降低 ,P值均 <0 .0 1。结论　超声组织定征视频法与射频法均能用于心肌声学造影的定量分析 ,两者均能区分缺血与梗塞心肌。     

组织速度成像技术对冠心病左室壁收缩运动异常的评价

目的探讨组织速度成像(TVI)评价冠状动脉粥样硬化性心脏病(冠心病)患者左室壁收缩运动异常的临床意义,比较TVI中定量组织速度成像(QTVI)、应变率成像(SRI)、组织追踪成像(TTI)和组织同步成像(TSI)之间对于评价左室壁收缩运动异常的敏感性差异。方法对正常组健康人群及冠心病组的病例应用TVI采集心尖四腔切面、心尖两腔切面、心尖左室长轴切面的后间隔、下壁、前壁及前间隔图像,获得QTVI、TSI的速度-时间曲线图,TTI的位移-时间曲线图及SRI的应变率曲线图,测量左室11个节段收缩期的峰值速度(Vp)、峰值位移(D)及最大应变率(SR)并进行定量分析。结果以正常组各节段各项指标为标准,冠心病组各节段的各项指标较对照组明显减低。冠心病组共208个节段,QTVI、SRI、TTI、TSI对异常节段的检出比例分别为56.73%、60.58%、67.79%、50.48%。结论TVI技术能有效地定量评价冠心病的左室壁收缩运动异常,其中尤以TTI对评价左室壁收缩运动异常最为敏感。