Comparison between conventional CT and grayscale inversion CT images in the assessment of the post-operative spinal orthopaedic implants

AimTo compare the accuracy of the inverted greyscale CT versus the conventional CT in the assessment of post-operative spinal orthopaedic implants and osseous fusion.Methods50 patients who had CT as part of their routine spinal implant follow up were evaluated for the presence of fusion, fracture and loosening with conventional CT and with greyscale inverted CT images. 3 independent observers assessed the images 2 months apart. Diagnostic performance (sensitivity and specificity) of the conventional and greyscale inversion images relative to the reference standard were calculated. Agreement with the reference standard was assessed using Cohen's kappa for conventional and greyscale inversion images.ResultsCorrect classifications increased when using the greyscale inverted CT images for each reader compared to conventional CT images (40–46, 39 to 42 and 41 to 44 (out of 50)). Inverted images demonstrated better agreement with the reference standard than conventional grayscale images for assessment of fusion (kappa of 0.588 for inverted CT versus 0.484 for conventional CT) and loosening (kappa 0.386 for inverted versus 0.293 for conventional). Sensitivity was increased for assessment of fusion and loosening. McNemar's test performed for assessment of sensitivity differences showed statistical significance (p = 0.038 for fusion and p = 0.0313 for loosening).ConclusionGreyscale inversion CT is a useful adjunct which has advantages (improved sensitivity and better agreement) over conventional CT imaging in cases of fusion and loosening of metallic implants following spinal instrumentation. We recommend the use of both the greyscale inversion CT images and conventional CT imaging when assessing post-operative spinal orthopaedic implants.     

从医务人员的证据意识谈举证责任倒置

文章从剖宫产术后伴发腰腿痛病例分析入手，认为举证责任倒置就在我们诊疗工作中，就在我们协调医患关系的过程中。因此需要在临床实践中去感悟举证责任置的深刻含义，从而树立证据意识，做好证据的收集与保存工作，一旦发生诉讼有证为据，并由此提出了“医学证据学”的构想，而医学证据的特点有待进一步深入研究。     

Chloroplast DNA from lettuce and Barnadesia (Asteraceae): structure,gene localization,and characterization of a large inversion

Summary We have cloned into plasmids 17 of 18 lettuce chloroplast DNA SacI fragments covering 96% of the genome. The cloned fragments were used to construct cleavage maps for 10 restriction enzymes for the chloroplast genomes of lettuce (Lactuca sativa) and Barnadesia caryophylla, two distantly related species in the sunflower family (Asteraceae). Both genomes are approximately 151 kb in size and contain a 25 kb inverted repeat. We also mapped the position and orientation of 37 chloroplast DNA genes. The mapping studies reveal that chloroplast DNAs of lettuce and Barnadesia differ by a 22 kb inversion in the large single copy region. Barnadesia has retained the primitive land plant genome arrangement, while the inversion has occurred in a lettuce lineage. The endpoints of the derived lettuce inversion were located by comparison to the well-characterized spinach and tobacco genomes. Both endpoints are located in intergenic spacers within tRNA gene clusters; one cluster being located downstream from the atpA gene and the other upstream from the psbD gene. The endpoint near the atpA gene is very close to one endpoint of a 20 kb inversion in wheat (Howe et al. 1983; Quigley and Weil 1985). Comparison of the restriction site maps gives an estimated sequence divergence of 3.7% for the lettuce and Barnadesia genomes. This value is relatively low compared to previous estimates for other angiosperm groups, suggesting a high degree of sequence conservation in the Asteraceae.     

The inversion effect on gaze perception reflects processing of component information

When faces are turned upside-down they are much more difficult to recognize than other objects. This "face inversion effect" has often been explained in terms of configural processing, which is impaired when faces are rotated away from the upright. Here we report a "gaze inversion effect" and discuss whether it is related to configural face processing of the whole face. Observers reported the gaze locations of photographed upright or inverted faces. When whole faces were presented, we found an inversion effect both for constant errors and observer sensitivity. These results were closely replicated when only the eyes were visible. Together, our findings suggest that gaze processing is largely based on component-based information from the eye region. Processing this information is orientation-sensitive and does not seem to rely on configural processing of the whole face.     

TI VIBE inversion MRI – An alternative to CT for imaging of hip pain

IntroductionMR and CT are excellent complimentary diagnostic modalities for evaluation of hip pain which are often used together along with radiographs. However, CT involves radiation, which is a concern particularly in younger patients. T1VIBE is a 3D gradient echo MR sequence with high intrinsic contrast between the bone and soft tissues with multiplanar capabilities.AimWe performed a study to assess if TIVIBE can be used to complement MR for evaluation of hip pain in young adults and to see if measurements and angles can be calculated using T1VIBE inversion images with similar accuracy to CT scan.Material and methodsA retrospective review of 50 patients aged less than 40 years, who had MR (including TIVIBE) and CT of pelvis was performed. Post surgical patients were excluded. Some important measurements such as Centre edge angle, Tonnis’ angle, anterior acetabular sector angle, posterior acetabular sector angle and acetabular version were independently measured by two readers on T1 VIBE inversion and CT images separately and measurements were compared. One reader performed the measurements again to assess for intra-observer error.ResultsThere was a female predominance (37 F, 13M) with an average age of 27.6 years (range of 17–39). There was no significant difference in the measurements between CT and TI VIBE inversion and there was good intra and interobservor reliability.ConclusionTI VIBE inversion sequence can be used as an alternative to CT with added advantage of alleviating the radiation exposure.     

180例孕中期胎儿羊水细胞染色体倒位的细胞遗传学分析

目的研究孕中期胎儿羊水染色体倒位与孕妇临床诊断之间的关系。方法通过对孕妇行羊膜腔穿刺,抽取羊水进行羊水细胞遗传学检查。胎儿染色体异常者需对父母进行外周血染色体检查。结果本实验室10364例羊水。共发现染色体倒位180例,其中9号染色体到位159例,占倒位总数的88．9％（159／180）,10例Y染色体倒位,占倒位总数的5．6％（10／180）,其余的倒位还涉及1、2、3、4、7、11、14、15、16、20号常染色体。结论不同的临床指针都有可能是胎儿染色体倒位。     

FLAIR血管高信号征在大脑中动脉供血区急性脑梗死中的临床价值

目的探讨磁共振液体衰减反转恢复(FLAIR)序列高信号血管征(HVS)在评估大脑中动脉供血区急性脑梗死患者病情严重程度及预后中的应用价值。方法回顾性分析大脑中动脉供血区急性脑梗死的患者共52例。根据T2 FLAIR图像上血管高信号征是否存在分为有血管高信号征组和无血管高信号组。比较两组患者弥散序列(DWI)上梗死体积大小、入院时及治疗10天后NIHSS评分、早期神经功能恢复情况及基本临床资料。结果大脑中动脉供血区急性缺血性脑梗死患者52例中无远端HVS组35例(67%)和远端HVS组17例(33%)中,梗死体积大小分别为(89.74±28.82)和(73.15±26.37),入院时NIHSS评分分别为16(6~27)分及10(2~21)分,入院10天NIHSS评分分别为13(6-26)和8(0~19)分,无远端HVS组与远端HVS组差异存在统计学意义(P<0.05)。梗死侧大脑中动脉狭窄程度分为轻度狭窄、明显狭窄、闭塞,HVS组的发生率分别为19例(42%)、11例(73%),16例(89%)。HVS组中大脑中动脉严重狭窄或闭塞者27例,占HVS阳性组77%,血管高信号征阴性组中大脑中动脉严重狭窄或闭塞者5例,占HVS阴性组29%,两组之间存在显著差异(P<0.05)。结论 T2 FLAIR序列HVS是大脑中动脉供血区急性脑缺血性梗死重要的影像学征象。有远端HVS的患者急性梗死灶体积较小,NIHSS评分较低,临床预后较好。责任血管狭窄程度越严重,HVS的出现率越高。大脑中动脉区HVS联合MRA有利于临床评估脑梗死的病变范围、血管病变的大致位置、血管的狭窄程度,可指导临床进行早期干预,改善患者的预后。     

MCI患者早期面孔知觉加工N170效应与翻转效应

目的探讨轻度认知障碍患者早期面孔知觉加工过程中N170效应与N170翻转效应。方法采用配伍组设计从潍坊潍柴社区退休职工中选取受试对象,刺激程序使用stim2软件编写,采用美国Neuroscan公司脑电信号采集记录仪记录脑电后进行离线分析并用SPSS18.0进行统计学分析。结果①MCI组与对照组均产生了明显的颞枕区分布的面孔特异性成分N170,且MCI组非靶刺激诱发的N170波幅比对照组降低(P<0.001),潜伏期延长(P<0.05)。②MCI组和正常老年人均产生N170效应(Nd170)以及N170翻转效应。结论 MCI患者存在早期面孔知觉加工障碍,可能发生在面孔基本分类水平,而结构信息的早期加工尚保持正常。     

时间-空间相关成像技术的反转模式在胎儿心血管成像中的应用进展

随着三维及四维超声技术的迅速发展,时间-空间相关成像技术(STIC)已成为研究胎儿心脏的一种相对成熟的技术,其多种成像模式可提供更多结构及血流的相关信息,为临床诊断提供依据。STIC技术的反转模式可更清晰、准确地呈现心室腔和血管腔的立体结构。本文就其在胎儿心血管系统中的研究进展进行综述。     

Linear Wavefield Optimization Using a Modified Source

Recorded seismic data are sensitive to the Earth's elastic properties, and thus, they carry information of such properties in their waveforms. The sensitivity of such waveforms to the properties is nonlinear causing all kinds of difficulties to the inversion of such properties. Inverting directly for the components forming the wave equation, which includes the wave equation operator (or its perturbation), and the wavefield, as independent parameters enhances the convexity of the inverse problem. The optimization in this case is provided by an objective function that maximizes the data fitting and the wave equation fidelity, simultaneously. To enhance the practicality and efficiency of the optimization, I recast the velocity perturbations as secondary sources in a modified source function, and invert for the wavefield and the modified source function, as independent parameters. The optimization in this case corresponds to a linear problem. The inverted functions can be used directly to extract the velocity perturbation. Unlike gradient methods, this optimization problem is free of the Born approximation limitations in the update, including single scattering and cross talk that may arise for example in the case of multi sources. These specific features are shown for a simple synthetic example, as well as the Marmousi model.