人脑桥内部的动脉供应和毛细血管构筑

采用血管灌注和透明切片,在立体解剖显微镜下对30例脑桥内部动脉的分群,经行分支和供应范围进行了观察。并应用图像分析系统测算了脑桥内部主要神经核团和纤维束的毛细血管密度。脑桥内部前正中群有三组长动脉,分别由脚间窝下端,基底沟中部和盲孔处穿入,这些动脉在向脑桥被盖部经行和分布的过程中,可形成多级直角分支,使之呈“垂柳状”外观。脑桥内部的毛细血管构筑,在透明切片上,可显示出神经结构的轮廓。其中上橄榄核的毛细血管密度最高,小脑上脚的毛细血管密度最低。     

不同形状界面对界面射流的影响──彩色多普勒与激光荧光染料方法的研究

本文通过应用彩色多普勒及激光荧光染料显示射流方法研究了不同形状界面对射流的影响。结果表明对照组及平坦界面射流时，彩色多普勒与激光荧光染料两种方法无显著差异；在弯曲界面条件下，彩色多普勒射流小于激光荧光染料射流（Ｐ＜０．０１～０．０００１）。彩色多普勒研究表明不同形状界面射流大小分别与每搏容量相关好（ｒ＝０．８３～０．９９），但射流大小明显不同。凹形界面射流面积最小，平坦及凸形界面射流面积也小于对照组。研究提示不同形状界面可以导致界面射流不同程度地减小，并且彩色多普勒也不易对弯曲界面的射流完全成像。在临床上应用彩色多普勒对返流定量时，需考虑上述影响。     

Flow karyotypes and chromosomal DNA contents of genus Triticum species and rye (Secale cereale)

The flow cytometry and chromosome imaging method were jointly used for analyzing genome content and chromosomal DNA content of hexaploid wheat (AABBDD), hexaploid triticale (AABBRR), tetraploid wheat (AABB), and AA, BB, DD genome donors and RR genome rye. Their genome sizes were 34.4 pg, 40.9 pg, 26.2 pg, 12.1 pg, 13.7 pg, 10.5 pg, and 16.9 pg, respectively. The 2C nuclear DNA content of BB genome donor with 13.7 pg was the highest value among the other genome donors, AA or DD. The genome content of tetraploid wheat, unlike hexaploid wheat or hexaploid triticale, was larger than the sum of the genomes of AA and BB genome donors. The DNA content of each chromosome ranged from 1.22 pg in DD genome donor to 2.61 pg in rye. Each chromosome peak was divided into three to four groups. Only one chromosome was included in the highest chromosomal DNA peak in hexaploid wheat, tetraploid wheat, DD genome donor and rye but two chromosomes in AA, BB genome donors, and hexaploid triticale. Correlation between 2C nuclear DNA content and chromosome density volume was the highest value compared with the other chromosomal parameters of chromosome area, or chromosome length.     

PQ系列CT机的数据采集和图像重建系统原理

本文介绍了数据采集系统、图像重建和显示系统的具体组成及完成的相应功能.     

翼管的多层螺旋CT影像解剖学研究

目的探讨正常翼管在多层螺旋CT(MSCT)及其重组图像上的影像解剖学特点和临床应用价值。方法对60例健康成年人和40例颌面部外伤病人(病变未波及翼管)进行MSCT颌面部轴位薄层螺旋扫描后,进行后处理重建,包括多平面重组(MPR)和容积显示(VR),并对三维图像进行旋转、切割及测量。结果翼管的形态、走行及其周围毗邻结构可在MSCT轴位扫描图像、MPR及VR三维切割图像中得到全面、清晰、立体直观的显示。结论多层螺旋CT二维及三维重建图像相结合可清晰、立体直观的认识翼管及其周围邻近骨性结构。     

Classification of spatiotemporal hemodynamics from brain perfusion MR images using expectation-maximization estimation with finite mixture of multivariate gaussian distributions.

The ability to cluster different perfusion compartments in the brain is critical for analyzing brain perfusion. This study presents a method based on a mixture of multivariate Gaussians (MoMG) and the expectation-maximization (EM) algorithm to dissect various perfusion compartments from dynamic susceptibility contrast (DSC) MR images so that each compartment comprises pixels of similar signal-time curves. This EM-based method provides an objective way to 1) delineate an area to serve as the in-plane arterial input function (AIF) of the feeding artery for adjacent tissues to better quantify the relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), and mean transit time (MTT); 2) demarcate regions with abnormal perfusion derangement to facilitate diagnosis; and 3) obtain parametric maps with supplementary information, such as temporal scenarios and recirculation of contrast agent. Results from normal subjects show that perfusion cascade manifests (in order of appearance) the arteries, gray matter (GM), white matter (WM), veins and sinuses, and choroid plexus mixed with cerebrospinal fluid (CSF). The averaged rCBV, rCBF, and MTT ratios between GM and WM are in good agreement with those in the literature. Results from a patient with cerebral arteriovenous malformation (CAVM) showed distinct spatiotemporal characteristics between perfusion patterns, which allowed differentiation between pathological and nonpathological areas.     

Primary diffuse leptomeningeal gliomatosis followed with serial magnetic resonance images

We report a case of primary diffuse leptomeningeal gliomatosis (PDLG) followed up with serial magnetic resonance images (MRI). A 45‐year‐old man manifested with bilateral abducens nerve palsy and meningisms. Repeated MRI revealed diffuse leptomeningeal enhancement throughout the central nervous system without intra‐axial mass accompanied with the dilatation of ventricles and focally enlarged cerebral sulci. Brain biopsies showed a leptomeningeal gliomatosis. The MRI findings described here would contribute to the diagnosis of PDLG among other common diseases diffusely spreading along the leptomeningeal structures.     

TIA磁共振弥散加权成像异常的相关因素分析

目的探讨短暂性脑缺血发作(TIA)磁共振弥散加权成像(DWI)异常的相关因素。方法对2006年1月～2006年12月临床诊断为TIA的住院患者45例进行回顾性分析,比较DWI异常组和正常组的临床特征,并采用Logistic回归分析判定与DWI异常有关的独立因素。结果DWI异常14例(31%);多元回归分析提示TIA症状持续时间≥1h(OR=2.5,95%CI:1.3～8.6)和症状表现为失语伴运动障碍(OR=8.9,95%CI:2.1～36.5)与DWI异常独立相关。结论TIA患者DWI异常与TIA症状持续时间和症状表现为失语伴运动障碍有关。     

棉织布与无纺布尘埃粒子数及抗渗液性能比较研究

目的比较棉织布与无纺布制作的手术衣和手术洞巾等在手术铺巾时空气中的尘埃粒子数及术中抗渗液性能，为有效控制外科切口感染和预防医患交叉感染提供参考。方法将棉织布与无纺布制作的手术布类各备15包，包内内容均相同，经灭菌处理。应用尘埃粒子计数仪测定两组铺巾时、铺巾后及收巾时空气中的尘埃粒子数，同时在手术过程中观察其抗渗液性能。结果无纺布组在铺巾时、铺巾后及收巾时产生的尘埃粒子数显著少于棉织布组（P〈0．05，P〈0．01）；其抗渗液率为100％，而棉织布组为0。结论无纺布抗渗液性能优，可减少手术环境中的尘埃粒子数，从而控制外科切口感染；其阻隔防护效能对患者和医护人员具有双重保护作用。     

Image size magnification and power and dilation factors for optical instruments in general

Traditional treatments of spectacle magnification for distant objects consider only stigmatic spectacle lenses and they compare the retinal image size in a refractively fully compensated eye with the image size in the uncompensated eye. Spectacle magnification is expressed as a product of two factors, the power and shape factors of the lens. The power factor depends on the position of the entrance pupil of the eye. For an eye with an astigmatic cornea, however, the position of the entrance pupil is not well defined. Thus, the traditional approach to spectacle magnification does not generalize properly to allow for astigmatism. Within the constraints of linear optics and subject to the restriction that the eye's iris remains the aperture stop, this paper provides a complete, unified and exact treatment for optical instruments in general. It compares retinal image size in a generalized sense (including image shape and orientation) for any instrument in front of an eye with that of the eye alone irrespective of whether the instrument compensates or not. The approach does not make use of the concept of the entrance pupil at all and it allows for astigmatism and for non-alignment of refracting elements in the instrument and in the eye. The concept of spectacle magnification generalizes to the concept of instrument size magnification. Instrument size magnification can be expressed as the product of two matrix factors one of which can be interpreted as a power factor (as back-vertex power) and the other factor for which the name dilation factor is more appropriate in general. The general treatment is then applied to a number of special cases including afocal instruments, spectacle lenses (including obliquely crossing thick bitoric lenses), contact lenses, stigmatic systems and stigmatic eyes. In the case of spectacle lenses, the dilation factor reduces to the usual shape factor.