乳腺对比增强能谱X线摄影的研究现状北大核心

对比增强能谱X线摄影(contrast enhancement spectral mammography, CESM)是在普通X线检查的基础上结合血管造影剂进行检查的一种新技术,是通过注射造影剂有效消除组织重叠对病灶的遮盖,实现对肿块真实形态显示,并提供血供信息。目前临床上对CESM进行了一系列的研究,本文就CESM成像原理、对乳腺癌的诊断、应用前景几个方面进行综述。     

双源CT多定量参数对胃癌的诊断价值及与HER2的相关性

目的:探讨门脉期双源CT多个定量参数与胃腺癌病理分化程度及HER2的相关性。方法: 回顾性分析2018年7月至2019年4月间于陕西省人民医院行双源CT双能量扫描的48例经胃镜活检(21例)或手术病理证实（27例）的胃腺癌及30例正常胃的影像学资料，其中27例HER2指标明确，通过西门子第二代双源CT扫描获得静脉期双能量图像，利用syngo.via软件获得曲线斜率、门脉期碘浓度、标准化碘浓度；将患者分为胃腺癌与正常胃壁组，高、中、低分化胃腺癌组，HER2阳性组（+，++，+++）与HER2阴性组（-）。统计学方法采用Kappa一致性检验、ROC曲线法、两独立样本t检验及方差分析。结果:活检与术后病理结果具有较强的一致性（Kappa系数为0.701），两者无明显差异；胃腺癌与正常胃壁两组间能谱曲线斜率（1.35±0.24、2.19±0.71）及标准化碘浓度（0.31±0.079、0.54±0.157）均具有统计学意义（P<0.05），曲线下面积分别为0.992、0.919；低分化、中分化及高分化胃腺癌能谱曲线斜率值（3.07±0.67，2.63±0.57，2.01±0.39）组间及组内差异均具有统计学意义（P<0.05），低分化、中分化及高分化胃腺癌门脉期标准化碘浓度(0.60±0.167，0.52±0.089，0.36±0.039)组间差异具有统计学意义（P<0.05），中分化组与低分化组差异无统计学意义（P>0.05），高分化组与中、低分化组均具有统计学差异（P<0.05）。HER2阳性组与阴性组的能谱曲线斜率及标准化碘浓度值无统计学差异（P>0.05）。结论:能谱曲线斜率及门脉期标准化碘浓度值有助于对胃腺癌进行诊断并推测病理分化程度；双源CT定量参数与免疫组化指标HER2无相关性。     

Practical uses of contrast‐enhanced spectral mammography in daily work: A pictorial review

Contrast‐enhanced spectral mammography (CESM) has a number of uses including the work‐up of inconclusive findings on mammography, assessment of breast symptoms, cancer staging, evaluation of response to neoadjuvant chemotherapy and recently as an alternative to magnetic resonance imaging (MRI) in high‐risk screening. CESM can be swiftly incorporated into the workflow of busy breast clinics. We share our experiences with CESM at a large breast assessment centre in Western Australia.     

GE宝石能谱CT故障分析

简要介绍了GE宝石能谱CT(Discovery CT750 HD)的技术特点,详细阐述了日常使用中出现的间歇性停机、无法进行Fastcal(快速空气校正)以及扫描中断和gantry(扫描架)自动复位3例故障的维修过程,为医院维修人员维修类似故障提供了参考。最后总结了医疗设备常见故障及主要故障原因,提出了快速排查CT故障的方法,并建议在日常使用中及时保养维护以降低设备故障率。     

Changes in electroencephalographic power and bicoherence spectra according to depth of dexmedetomidine sedation in patients undergoing spinal anesthesia

Background: Assessment the depth of dexmedetomidine sedation using electroencephalographic (EEG) features can improve the quality of procedural sedation. Previous volunteer studies of dexmedetomidine-induced EEG changes need to be validated, and changes in bicoherence spectra during dexmedetomidine sedation has not been revealed yet. We aimed to investigate the dexmedetomidine-induced EEG change using power spectral and bicoherence analyses in the clinical setting.Patients and Methods: Thirty-six patients undergoing orthopedic surgery under spinal anesthesia were enrolled in this study. Dexmedetomidine sedation was conducted by the stepwise increase in target effect site concentration (Ce) while assessing sedation levels. Bispectral index (BIS) and frontal electroencephalography were recorded continuously, and the performance of BIS and changes in power and bicoherence spectra were analyzed with the data from the F3 electrode.Results: The prediction probability values for detecting different sedation levels were 0.847, 0.841, and 0.844 in BIS, 95% spectral edge frequency, and dexmedetomidine Ce, respectively. As the depth of sedation increased, δ power increased, but high β and γ power decreased significantly (P <0.001). α and spindle power increased significantly under light and moderate sedation (P <0.001 in light vs baseline and deep sedation; P = 0.002 and P <0.001 in moderate sedation vs baseline and deep sedation, respectively). The bicoherence peaks of the δ and α-spindle regions along the diagonal line of the bicoherence matrix emerged during moderate and deep sedation. Peak bicoherence in the δ area showed sedation-dependent increases (29.93%±7.38%, 36.72%±9.70%, 44.88%±12.90%; light, moderate, and deep sedation; P = 0.008 and P <0.001 in light sedation vs moderate and deep sedation, respectively; P = 0.007 in moderate sedation vs deep sedation), whereas peak bicoherence in the α-spindle area did not change (22.92%±4.90%, 24.72%±4.96%, and 26.96%±8.42%, respectively; P=0.053).Conclusions: The increase of δ power and the decrease of high-frequency power were associated with the gradual deepening of dexmedetomidine sedation. The δ bicoherence peak increased with increasing sedation level and can serve as an indicator reflecting dexmedetomidine sedation levels.     

Optimal spatial field control for controlled release

Most distributed parameter control problems involve manipulation within the spatial domain. Such problems arise in a variety of applications including epidemiology, tissue engineering, and cancer treatment. This paper proposes an approach to solve a state‐constrained spatial field control problem that is motivated by a biomedical application. In particular, the considered manipulation over a spatial field is described by partial differential equations (PDEs) with spatial frequency constraints. The proposed optimization algorithm for tracking a reference spatial field combines three‐dimensional Fourier series, which are truncated to satisfy the spatial frequency constraints, with exploitation of structural characteristics of the PDEs. The computational efficiency and performance of the optimization algorithm are demonstrated in a numerical example. In the example, the spatial tracking error is shown to be almost entirely due to the limitation on the spatial frequency of the manipulated field. The numerical results suggest that the proposed optimal control approach has promise for controlling the release of macromolecules in tissue engineering applications.     

Bioreplicated visual features of nanofabricated buprestid beetle decoys evoke stereotypical male mating flights

Recent advances in nanoscale bioreplication processes present the potential for novel basic and applied research into organismal behavioral processes. Insect behavior potentially could be affected by physical features existing at the nanoscale level. We used nano-bioreplicated visual decoys of female emerald ash borer beetles (Agrilus planipennis) to evoke stereotypical mate-finding behavior, whereby males fly to and alight on the decoys as they would on real females. Using an industrially scalable nanomolding process, we replicated and evaluated the importance of two features of the outer cuticular surface of the beetle’s wings: structural interference coloration of the elytra by multilayering of the epicuticle and fine-scale surface features consisting of spicules and spines that scatter light into intense strands. Two types of decoys that lacked one or both of these elements were fabricated, one type nano-bioreplicated and the other 3D-printed with no bioreplicated surface nanostructural elements. Both types were colored with green paint. The light-scattering properties of the nano-bioreplicated surfaces were verified by shining a white laser on the decoys in a dark room and projecting the scattering pattern onto a white surface. Regardless of the coloration mechanism, the nano-bioreplicated decoys evoked the complete attraction and landing sequence of Agrilus males. In contrast, males made brief flying approaches toward the decoys without nanostructured features, but diverted away before alighting on them. The nano-bioreplicated decoys were also electroconductive, a feature used on traps such that beetles alighting onto them were stunned, killed, and collected.Biomimicry of insect visual communication signals has received much recent attention, with growing interest in nanofabrication processes that result in artificially produced structural colors (1) such as those emanating from the ridges on butterfly wing scales (2). The fidelity of the nanoreplication of visual signals with communication value to such organisms has been underexplored, however. Visually induced behavior in arthropods often integrates color and edge-motion detection, with interactions often involving a variety of biotic and abiotic entities, making it difficult to reproduce experimentally (3).Bioreplication of visual signaling structures might be manipulated so as to provide insight into the mechanisms of such signaling processes; however, all currently known examples of bioreplicated nanostructures that have been created to affect behavior involve unicellular movements across particular textured environments (4–7), rather than directed to evoke responses of specialized sensory organs of more complex multicellular organisms. Bioreplicated structures emitting behaviorally effective visual cues also may be useful for such practical purposes as the monitoring and detection of pest species, but the communication efficacy of the bioreplica needs to be validated under field conditions using naturally occurring (i.e., wild) populations.In contrast, biomimicry of chemical signals, such as insect pheromones, has been a burgeoning field for more than half a century. Synthetically reproduced pheromones have been successfully applied under field conditions to manipulate insect behavior for invasive species pest detection, population monitoring of endemic species, and disruption of mating. Thousands of studies have described the essential components of nanoscale levels (nanograms) of semiochemical signals that trigger behavioral responses, such as upwind flight for mating (8), alarm responses (9), and trail following (10). Furthermore, neurophysiological techniques have elucidated how these signals are transduced by peripheral sensory organs (11) and integrated into odor sensations in the higher processing centers of the insect brain (12). In the realm of applied science, these insights have led to trapping protocols for pest population detection, attract-and-kill protocols, and mating disruption (13). Visually attractive features of trapping technologies generally have not been approached with such rigor, however, and are usually optimized by simple manipulations of trap colors without efforts to understand the underlying mechanisms of visual attraction.In an effort to initiate such an approach to manipulation of visual signaling systems, we used an industrially scalable nano-bioreplication technique (14) to produce high-fidelity replicas of the structural features of the cuticle of the hard wing covers (elytra) of an invasive buprestid beetle pest, the emerald ash borer (Agrilus planipennis). This species is a tree-killing pest of Asian origin whose visual signal is emitted by the elytra of a female at rest on an ash leaf in direct sunlight, which triggers attraction of flying males that are patrolling the canopy. Male responses unfold as rapid flights toward the females from heights of up to 2 m, usually terminating with the males alighting directly on the females and attempting to copulate (15). This “paratrooper” descent behavior by flying A. planipennis males in the field can be repeatedly evoked by affixing dead A. planipennis females to ash leaves (15, 16). Furthermore, various other potentially invasive European and North American tree-feeding Agrilus species have been observed performing similar stereotypical inflight descents onto dead beetle decoys affixed to the leaves of preferred host trees (17, 18). Such approaches are often seen to congeneric, heterospecific targets. One such species, the two-spotted oak borer, Agrilus biguttatus, that is similar in size and habits to A. planipennis is known to kill oak trees within its native range in Europe (19), particularly after drought (20) or defoliation events (21).The base colors of many metallic-colored beetles, including buprestid beetles (Fig. 1A), are known to be structurally produced by the repeated alternation of cuticle layers (Fig. 1D) with different refractive indices (22, 23). This periodically multilayered assemblage functions as a quarter-wave Bragg stack reflector in a particular spectral regime (2) and is thus highly effective for creating a color of narrow specificity in sunlight, unlike many naturally occurring pigments. The reflected light is also affected by regular fine-scale topographic features of the surface, including thousands of sharp spicules each emitting green to yellow colors, which are further scattered by numerous spines (Fig. 1 B and C). Many of the physical attributes of the A. planipennis cuticle that produce its attractive visual signal have been replicated by a process that involves the stamping of a polymer quarter-wave Bragg stack reflector with a set of dies cast from the actual elytra of a female A. planipennis (Fig. 2) (14).Open in a separate windowFig. 1.Structural color and surface topography of A. planipennis wings. (A) Optical microscopy showing a dorsal view of the beetle elytron. (B) Higher-magnification optical microscopy showing spines and cilia. (C) Scanning electron micrograph showing a higher-resolution image of the surface topography. (D) Transmission electron micrograph of a cross-section of an elytron, showing four alternating layers of differing refractive indices. (C and D are reprinted with permission from ref. 14.)Open in a separate windowFig. 2.Nano-bioreplicated decoy characteristics. (A) Optical microscopy of the nickel die. (B) Scanning electron micrograph of a nickel die used for bioreplication, showing a similar structure as the A. planipennis surface (Fig. 1), but without the cilia. (C) Optical microscopy of the dorsal view of a nano-bioreplicated A. planipennis decoy that reproduces the surface structure of the beetle and is colored by metallic paint. (A and B are reprinted with permission from ref. 14.)Here we report on direct field observations of A. planipennis and A. biguttatus male behavior toward natural beetle decoys versus three types of synthetic decoys with varying degrees of verisimilitude with respect to the fidelity of bioreplication. These synthetic decoys included: (i) a bioreplicated decoy created by a nanomolding process and colored with a polymer functioning as a Bragg reflector; (ii) another bioreplicated decoy created by a nanomolding process and colored with a metallic green paint; and (iii) a 3D-printed decoy consisting of a smooth polymer surface without a nanomolded bioreplicated surface structure, also colored with green metallic paint. We investigated whether the nanomolding process could create light-scattering patterns similar to those of real decoys by observing light emissions resulting from the application of a white laser to the surfaces of real and synthetic decoys in a dark room. We hypothesized that a sufficient degree of verisimilitude with respect to color and fine-scale topological features of the elytra could be achieved through the bioreplication process to elicit inflight mating approaches and landings similar to those evoked by real beetles. We also incorporated the bioreplicated decoys into a trapping system in which the electroconductive properties of the decoy are used to electrocute male beetles when they approach and alight on the decoys.