An efficient locally affine framework for the smooth registration of anatomical structures

Intra-subject and inter-subject nonlinear registration based on dense transformations requires the setting of many parameters, mainly for regularization. This task is a major issue, as the global quality of the registration will depend on it. Setting these parameters is, however, very hard, and they may have to be tuned for each patient when processing data acquired by different centers or using different protocols. Thus, we present in this article a method to introduce more coherence in the registration by using fewer degrees of freedom than with a dense registration. This is done by registering the images only on user-defined areas, using a set of affine transformations, which are optimized together in a very efficient manner. Our framework also ensures a smooth and coherent transformation thanks to a new regularization of the affine components. Finally, we ensure an invertible transformation thanks to the Log-Euclidean polyaffine framework. This allows us to get a more robust and very efficient registration method, while obtaining good results as explained below.We performed a qualitative and quantitative evaluation of the obtained results on two applications: first on atlas-based brain segmentation, comparing our results with a dense registration algorithm. Then the second application for which our framework is particularly well suited concerns bone registration in the lower-abdomen area. We obtain in this case a better positioning of the femoral heads than with a dense registration. For both applications, we show a significant improvement in computation time, which is crucial for clinical applications.     

鼠曲草对大鼠肺癌形成的抑制作用研究林伟青,林飞, 王海东

目的　观察鼠曲草提取液对3,4-苯并芘大鼠肺内注射诱发肺癌的抑制作用,并初步探讨其机制。方法　将120只ＳＤ大鼠随机分为四组,各30只。经胸壁肺内注射3,4-苯并芘2mg/次,每周1次,共4次诱发肺部肿瘤,对照组正常饮水,高、中、低剂量组分别以高、中、低浓度鼠曲草提取液代水喂食,于半年后处死全部大鼠,取其肺组织标本,观察其成瘤率差别。TUNEL法检测肿瘤细胞调亡情况。RT－PCR法检测大鼠肺癌组织survivin表达。结果　高、中、低浓度组大鼠肺癌成瘤率分别为36.67%(11/30)、43.33%(13/30)、55.17%(16/29),而对照组大鼠肺癌成瘤率为72.41%(21/29)。TUNEL法原位检测发现鼠曲草提取液可显著促进肺癌细胞的调亡,且与浓度相关。大鼠肺癌组织survivin表达显示鼠曲草提取液可显著降低大鼠膀胱癌组织中survivin表达。结论 鼠曲草提取液对大鼠肺癌形成有明显抑制作用。     

遗传算法在医学图像配准技术中的应用

采用遗传算法实现了多模 3D医学图像的仿射配准 ,并针对经典遗传算法后期收敛速度缓慢 ,易陷入局部极值的特点做了相应改进 ,实验结果表明 ,改进后的分阶段编码的遗传算法能加速配准进程 ,该算法对图像配准时间基本恒定 ,有利于临床实际应用     

Prospective correction of affine motion for arbitrary MR sequences on a clinical scanner.

The concept of prospective 3D affine motion correction was generalized, based on the Bloch equations, for signal excitation and sampling using arbitrary MR sequences. The technique was implemented on a clinical MRI scanner for Cartesian, radial, and spiral imaging sequences, as well as for 2D spatially selective RF excitation pulses. A patient-specific motion model steered by real-time navigators was employed to account for the additional degrees of freedom provided by the affine motion model. Different navigator concepts (multiple spatial and temporal navigators, quadratic navigators and other motion sensors) were investigated, with the aim of improving the correlation between navigator information and the motion model. Experiments on moving phantoms are presented to prove the technical feasibility of the approach. In vivo experiments on coronary MRA and renal MRI show the potential of the method for cardiac and abdominal applications hampered by respiratory motion.     

A modality-independent approach to spatial normalization of tomographic images of the human brain

A modality-independent approch for interactive spatial normalization of tomographic images of the human brain is described and its performance evaluated. Spatial normalization is accomplished using a nine-parameter affine transformation to interactively align and adjust the shape of a subject brain to the reference brain detailed in the 1988 atlas of Talairach et al. A user-friendly software application was developed using the X-windows Motif environment to guide the user through this process. This software supports data types from a wide variety of tomographic imagers and produces output in spatially concise formats. The parameters used for spatial alignment and shape normalization are presented and methods to apply them discussed. Where normalization parameters cannot be obtained directly from the image, as with positron emission tomography (PET), methods for estimating them are given. Evaluation of a new four-landmark method to fit the AC-PC line in 16 magnetic resonance imaging (MRI) studies indicated an average difference assessed as the distance between the true and fitted AC-PC line at four locations of 0.82 mm when using a 2-D weighted fit. The same landmarks were evaluated using lower spatial resolution PET-like images simulated from the 16 MRI studies. The difference between the PET and MR image volumes following alignment was minimal, with mean rotational differences of less than 0.2 deg and mean translational differences of generally less than 2 mm. Spatial normalization is illustrated for single photon emission computed tomography (SPECT), X-ray computed tomography (CT), PET, and MR image volumes. Modality-independent spatial normalization can be consistently and reliably performed with the methods and software presented. © 1995 Wiley-Liss, Inc.     

鼠曲草提取物对COPD模型大鼠气道炎症的抑制作用及对NF-κB通路的影响

目的:研究鼠曲草提取物对慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)模型大鼠气道炎症的影响及作用机制。方法:大鼠随机分为正常组,模型组,鼠曲草提取物低、中、高剂量组(0.75,1.5,3g·kg^-1)和地塞米松组(阳性对照药,27mg·kg^-1),每组9只。除正常组外,其余各组大鼠采用香烟烟熏联合气管内滴注脂多糖建立COPD大鼠模型。造模15d后,各给药组大鼠灌胃相应药物,正常组和模型组大鼠灌胃等体积0.9%氯化钠溶液,每日1次,连续14d。末次给药后,检测各组大鼠肺功能;HE染色观察肺组织病理学变化;酶联免疫法检测肺泡灌洗液、血清中IL-6、IL-8、IL-17、IL-1β、TNF-α、TGF-β含量;RT-PCR法检测右肺组织中NF-κB mRNA的相对表达量;Western blot法检测右肺组织中NF-κB、IKKβ、IκBα及其p-IκBα蛋白的相对表达量。结果:不同剂量的鼠曲草提取物干预后,均可显著提高大鼠肺功能参数FEV0.3、FVC、FEV0.3/FVC,明显降低肺泡灌洗液中IL-8、IL-17、TNF-α及血清中IL-1β、IL-6、IL-8、IL-17、TNF-α、TGF-β含量,改善大鼠肺组织病理变化,同时显著降低p-IκB、IKK蛋白及NF-κB mRNA和蛋白相对表达量。结论:鼠曲草能够改善COPD模型大鼠的肺功能,减轻肺组织病理损伤,抑制炎症反应,其作用可能与抑制NF-κB信号通路有关。     

鼠曲草对大鼠膀胱癌形成的抑制作用研究

目的:观察鼠曲草提取液对N-甲基亚硝基脲(MNU)诱发膀胱肿瘤的抑制作用,并初步探讨其机制。方法:将120只SD大鼠按照随机数字表法分为对照组、高、中、低剂量组4组,每组30只。经膀胱内灌注MNU(1 mg/次,1次/2周,共4次)诱发膀胱肿瘤,对照组正常饮水,高、中、低剂量组分别以高、中、低剂量鼠曲草提取液代水喂食,于第12周处死全部大鼠,取其膀胱组织标本,观察其成瘤率。TUNEL法检测肿瘤细胞调亡情况,反转录聚合酶链反应(RT-PCR)法检测大鼠膀胱癌组织存活蛋白(Survivin)表达。结果：高、中、低剂量组大鼠膀胱癌成瘤率分别为60%(18/30)、75.86%(22/29)、86.21%(25/29),而对照组大鼠膀胱癌成瘤率为100%(28/28)。TUNEL法原位检测发现鼠曲草提取液可显著促进膀胱癌细胞的调亡,且与剂量相关;大鼠膀胱癌组织Survivin表达显示鼠曲草提取液可显著降低大鼠膀胱癌组织中Survivin表达。结论：鼠曲草提取液对大鼠膀胱癌形成有明显抑制作用。     

Acute and sub-acute toxicities of hydroalcoholic extract of Allium affine aerial parts in rats

Objective:To assess the potential toxicity of hydroalcoholic extract of Allium affine(A.affine)aerial parts after acute and sub-acute administration in female and male Wistar rats.Methods:For acute toxicity assay,animals orally received the limit test dose of 2000 mg/kg of A.affine extract and were observed for 2 weeks.For sub-acute toxicity study,rats were orally treated with 125,250,and 500 mg/kg/day of the extract over 28 days,and hematological,biochemical,and histological evaluations were then conducted.Results:All rats were alive with normal body weight gain over 14 days,with LD50˃2000 mg/kg.No abnormality in body weight changes but significant increases in the relative weight of spleen and lung were detected after administration of the highest dose of extract for 28 days in sub-acute assay.Hematological analysis showed prominent elevations in total white blood cells in male rats and neutrophils count in female rats after exposure to 500 mg/kg of A.affine extract.In biochemical evaluations,significant increases in serum creatinine level(female rats,250 and 500 mg/kg)and in aspartate aminotransferase(male and female rate,500 mg/kg)and alanine aminotransferase(male,250 and 500 mg/kg and female,500 mg/kg)activities,however,notable decreases in serum blood glucose(male rats,125 and 500 mg/kg),triglycerides(male rats,500 mg/kg and female rates,250 mg/kg),and low-density lipoprotein cholesterol levels(male,250 mg/kg)were found.Histological examinations presented slight portal inflammation in liver tissue,moderate pneumocyte hyperplasia,congestion and peri-bronchial inflammation in lung tissue,and mild histiocytosis and lymphoid follicular activation in spleen tissue after exposure to 500 mg/kg of A.affine extract in male and female animals.Conclusions:The present investigation reveals the safety of A.affine extract at doses of lower than 250 mg/kg in rats and monitoring of lung,spleen,and liver functions is suggested during excessive and prolonged uses.     

高效液相色谱法测定秋鼠麴草中总黄酮的含量

目的建立秋鼠麴草提取物中总黄酮含量高效液相色谱的测定方法。方法选择乙醇浓度、料液比和提取时间这3个因素进行正交试验,初步优选出常规热回流法提取总黄酮的最佳工艺。色谱柱为HypersilODS2 C18柱（250 mm×4.6 mm,5μm）;流动相为甲醇∶水=33∶67;紫外检测波长为359 nm;流速1.0 ml/min;柱温35℃;以芦丁为对照计算总黄酮含量;进样量10μl。结果最优的总黄酮提取条件为：60%乙醇溶液、料液比为1∶35、提取时间为60 min。芦丁在0.013 2～0.105 6 mg/ml范围内线性良好,样品平均回收率为98.98%,相对标准偏差（RSD）为1.86%。结论利用高效液相色谱法测定秋鼠麴草热回流提取物中总黄酮含量的方法回收率高、精密度好、重复性好,能为药材鼠麴草的质量评价和控制提供可行方法。     

X线头影测量中标志点的自动识别

目的：对X线头影测量分析中标志点实现自动识别。方法：在自动定点过程中，对于不同的标志点采用不同的方法。选择合适的模板匹配方法应用于头影图像，可以确定孤立标志点。对于依附于边缘的标志点采用边缘检测的方法。首先对标准图像的特征边缘利用仿射变换确定被测图像特征边缘的初始位置。然后采用基于仿射变换的模板匹配方法，将模板匹配和仿射变换结合起来，调整图像的初始边缘。最后采用跟踪虫技术对边缘作进一步的修正。根据提取的边缘曲线的特征和标志点的几何特性能够确定依附于边缘的标志点。结果：避免了由于头影图像中有些目标在不同图像中的位置存在差异或形变而不能识别目标的缺陷，能更准确地判断 目标。结论：该技术能较好的确定X线头影图像中常用的测量标志点。