TQA数据趋势与TomoTherapy输出稳定性的联系

目的:探讨TomoTherapy QualityAssurance（TQA）数据趋势与螺旋断层放疗（Helical Tomotherapy，HT）系统输出的 联系。方法:回顾性分析了本院HT系统近3年内TQA各个模块的参数和数据趋势，探讨其与HT系统的静态输出剂量和 输出能量（D20/D10）变化的相关性。结果:楔形阶梯静态模块的z轴偏移参数与HT的静态输出剂量的相关性最强（r=0.883, P<0.01）。基本剂量测定模块的出口检测器平整度值对能量变化最敏感（r=0.902），其次是楔形阶梯静态模块的能量差异 （r=0.897）和楔形阶梯螺旋模块的能量差异（r=0.852），灵敏度分别为2.3×10-4、3.1×10-4和5.7×10-4。结论:TQA有助于用户 追踪HT输出剂量和能量变化，及早进行必要的机器维护或剂量校准。     

Mandibular fracture not shown by axial computed tomography: Benefit of computed reformation

A 36-year-old man was brought to the emergency department after being assaulted. A mandible series showed a nondisplaced fracture through the angle of the mandible extending through the left third molar tooth. Axial slices from a nonhelical computed tomographic (CT) examination of the head as well as a helical CT examination of the mandible failed to demonstrate the fracture. The fracture was well shown, however, on sagittal CT reformations. Although CT is generally regarded as more sensitive than plain radiography for the detection of fractures, fractures may be overlooked by CT if examination in only one plane is performed.     

Focused helical appendiceal computed tomography: Technique and interpretation

This article reviews a focused helical appendiceal computed tomographic technique and discusses an approach to appendiceal computed tomographic interpretation.     

Tau immunoreactivity and SDS solubility of two populations of paired helical filaments that differ in morphology

To further understand the processes that lead to the formation of neurofibrillary tangles from paired helical filaments (PHF) in Alzheimer brains, we studied two morphologically distinct fractions of PHF separated on sucrose density gradient. In a fraction with mostly short and non-aggregated PHF, the majority of filaments could be solubilized in SDS. In a fraction containing primarily PHF aggregated into clusters or bundles, sometimes resembling neurofibrillary tangles, filaments were less soluble in SDS. Immunogold labelling with a panel of tau-immunoreactive antibodies demonstrated that N-terminal epitopes of tau were preserved in the short filaments, but were reduced or absent in aggregated filaments. In contrast, C-terminal epitopes were present in both fractions. Furthermore, the accessibility of the microtubule-binding domain to immunolabelling was markedly impaired in short and non-aggregated filaments compared to aggregated filaments. These results are consistent with proteolytic degradation of the N-terminal epitopes and preservation of the C-terminal epitopes and the microtubule-binding domain of tau in the aggregated filaments. Partial proteolysis may be involved in the generation of aggregated PHF in neurofibrillary tangles.     

螺旋CT多平面重建对寰枢椎改良后路经关节螺钉内固定的意义

目的通过对正常人螺旋CT多平面重建检查，并对其行后路经关节螺钉内固定技术相关形态学参数的测量，为临床提供患者个体化手术相关信息。方法对60例正常人进行寰椎的螺旋CT检查，获取相关参数并进行分析。采用枢椎下关节突正中为进钉点模拟寰枢椎后路经关节螺钉内固定术，在螺旋CT重建上获得轴面和矢状面的正确倾斜角度。C2峡部高度和宽度，理想的螺钉长度，理想的螺钉矢状面和轴面倾斜度，以及理想的螺钉路径与椎动脉沟之问距离。结果C2峡部高度为（8．02±1．92）mm，峡部宽度（6．05±1．32）mm，理想的螺钉长度为（41．22±4．48）mm，螺钉矢状面倾斜度为53．87°±5．61°，与内向成角（14．81°±2．81°）。10侧（8％）峡部狭窄（宽度或高度小于5mm），测量其椎动脉沟与理想螺钉途径之间距离，有12例（10％）小于2．5mm，因此总共有22侧（18％）存在潜在椎动脉损伤风险。结论术前对每个患者行CT检查十分必要，能充分地了解个体的解剖结构，提高手术的安全性。     

Solubility of neurofibrillary tangles and ultrastructure of paired helical filaments in sodium dodecylsulphate

Summary Temporal cortex from 14 cases of Alzheimer-type dementia and 6 cases of Down's syndrome, all selected for severe Alzheimer pathology, was homogenised in distilled water, NaOH, or sodium dodecylsulphate (SDS) containing 0.1% -mercaptoethanol. The homogenates were stained with Congo red, and the neurofibrillary tangles and plaque cores were counted under crossed-polarisation microscopy. The number of tangles and plaque cores in the water-treated extracts was not related to age, sex, postmortem interval or duration of dementia. The number of tangles after extraction in SDS or NaOH, as a percentage of tangles in water-treated extracts, was 57±25 (mean±SD) for 1% SDS, 43±17 for 5% SDS and 37±22 for 0.2 M NaOH. Plaque cores were essentially insoluble in all three agents. The percentage of tangles insoluble in 1% SDS did not correlated with age or post-mortem interval but decreased with increasing duration of dementia. Enhanced tangle solubility with increasing duration of dementia suggests that the nature of tangles changes with time; one possibility is that this reflects transformation of intracellular to extracellular tangles. Paired helical filament (PHF) length and the number of repeats per PHF were measured in electron micrographs of PHF prepared with and without treatment by 1% SDS. There was no significant multimodality of PHF length to suggest that PHF broke at regular intervals. The mean repeat length (PHF length/number of repeats) was greater for PHF isolated in the presence of 1% SDS than in its absence, showing that SDS affects ultrastructure by untwisting PHF. An untwisting process may also occur in vivo producing the straight filaments found, together with PHF, in tangles and neurites.Supported by Miss E. Buchan (to the MRC Brain Metabolism Unit) and the British Foundation for Age Research and the Wellcome Trust (to P. A. M. Eagles). S. Hussey was in receipt of an MRC Partnership Award.     

Spectrum of morphological appearance of amyloid deposits in Alzheimer's disease

Summary Immunocytochemical staining with monoclonal antibodies to the -protein on tissue sections which have been pretreated with formic acid is not only a very specific but also a highly sensitive method for the detection of amyloid deposits in the brains of Alzheimer's disease victims. We report here a spectrum of morphological appearance of the brain amyloid deposits which are one of the main histopathological correlates of this disorder. Deposits of the -protein are not only found in the well-known lesions [congophilic angiopathy and senile (neuritic) plaques] but are also seen under various morphological forms for which the word plaques does not appear an appropriate term: amyloid fibrils are found as large areas of diffuse infiltration of the neuropil, as ribbon-like infiltration in the subpial layer of the cerebral cortex, as granular deposits in the white matter, as diffuse deposits in the molecular layer of the cerebellum and the basal ganglia and as star-shaped deposits in the cerebellar Purkinje cell layer. The morphology of these deposits seems to depend on the cyto-and fibroarchitectonics of the brain region in which they are found, on the amount of amyloid deposited, and also on the type of staining technique used. It is only under specific circumstances that the deposition of amyloid in the neuropil is accompanied by the formation of paired helical filaments in nerve cell processes and their parent perikarya. In conclusion, our studies suggest that the extent of brain amyloidosis in Alzheimer's disease is much wider than so far appreciated.Supported in part by grants 5-AGO-4220-05 and 5-HD-22634-02 from the National Institutes of Heath     

Altered structural proteins in plaques and tangles: What do they tell us about the biology of Alzheimer''s disease?

The progressive dysfunction and loss of neurons in Alzheimer's disease (AD) is accompanied by marked structural changes in innumerable neuronal cell bodies and neurites, particularly in limbic and association cortices. Qualitatively indistinguishable neuronal lesions occur in much smaller numbers during normal aging. Highly insoluble paired helical filaments (PHF) and antigenically related straight filaments accumulate in perikaryal tangles and the neurites of neuritic plaques. In addition, PHF antibodies reveal the presence of PHF antigens in many individual cortical neurites not clustered into discrete plaques. Recent studies in several laboratories indicate that altered forms of the microtubule-associated phosphoprotein, tau, are important constituents of PHF. Other neuronal cytoskeletal proteins, particularly microtuble-associated protein 2 and neurofilament, have also been associated with PHF. In contrast, the extracellular amyloid filaments found in the centers of many neuritic plaques and in cortical and meningeal vessels appear to be composed of hydrophobic low molecular weight protein(s) distinct from PHF. A major question for further study regards the cellular origin and role of microvascular amyloid in the degeneration of neurites of multiple neurotransmitter specificities in AD cortex. The widespread neuritic and perikaryal alterations in brain tissue are likely to represent, at least in part, the morphological substrate of cortical dysfunction in AD.     

原发性巨块型肝癌螺旋CT多期增强扫描的临床价值

目的：分析巨块型肝癌螺旋CT多期增强扫描的表现,评价其诊断价值。方法：应用螺旋CT对48例经临床手术或病理结果证实的巨块型肝细胞癌病人分别行肝区平扫、增强后全肝双期或三期螺旋扫描,观察和分析瘤灶及肝内转移性子灶的多期动态增强扫描的CT征象。结果：（1）肝动脉期肿瘤实质出现密度高于肝实质的肿瘤血管和瘤区强化,门静脉期其密度迅速降低,至平衡期为低密度。（2）肿瘤边缘于肝动脉期和门静脉期均可见环行强化。（3）转移性子灶仅在肝动脉期明显强化,门脉期全瘤密度迅速降至等密度;（4）门静脉受累表现为肝内分支的边缘侵蚀、破坏、中断,或为不规则的充盈缺损。结论：多期螺旋CT增强扫描能显示肝癌“快进快出”的增强特点,明确肿瘤的供血特征和门脉受累情况,检出伴发的肝内转移性子灶,为明确诊断和指导治疗提供了可靠的影像依据。     

螺旋CT双期增强扫描对肝脏占位性病变的诊断价值

目的 探讨螺旋CT双期扫描对肝脏占位性病变的诊断价值。方法 对98例肝内占位性病变的病人进行螺旋CT双期增强扫描。结果 98例病人中肝癌48例,肝转移瘤19例,肝血管瘤31例。结论 螺旋CT扫描速度快,在动脉期和门静脉期分别完成全肝扫描,弥补了一般动态扫描的缺点,对肝内病灶的检出和定性有重要价值。