Automated classification of neonatal sleep states using EEG

Objective

To develop a method for automated neonatal sleep state classification based on EEG that can be applied over a wide range of age.

组合式外固定器最佳拆除 时间及有关问题探讨

作者１９９２年６月－１９９４年１２月，用组合式外固定器治疗胫腓骨骨折２４例，治疗过程中应用Ｂ超直方图检测骨愈合，为固定器高速及拆除提供量化指标。固定后６周，Ｂ超直方图值达到健侧５０％－６０％，拆除外固定更换夹板或行走石膏，为骨愈合创造较好力学环境，骨折在１０－１４周愈合，比通常认为需要３－５月更短。     

肺癌放疗后放射性肺炎剂量学相关预测因素的研究进展

放射性肺炎（radiation pneumonitis,RP）是肺癌放射治疗的主要并发症之一,本文现将近年来通过剂量体积直方图（dose-volume histograms,DVH）有关参数评估放射性肺损伤的研究现状并作系统回顾。     

医学图像的边缘检测及特定区域灰度值的跟踪显示方法

利用MATLAB7．0图像处理函数和编程技巧，可展示医学图像的轮廓线、内部组织的边缘线和灰度直方图，对图像选定区域进行自由放大和缩小，利用图像处理工具显示任意区域的灰度值，并能自如测量两点间的距离，可以对图像分割技术中的不同方式进行灵活对比．为临床诊断提供有用的参考。     

不同肺体积确定方法和剂量分割方法对肺剂量体积参数的影响

目的 分析不同肺体积确定方法和不同剂量分割方法对肺剂量体积参数的影响.方法 随机搜集20例肺癌患者,根据病情以瓦里安Eclipse TPS进行三维适形治疗计划设计.以不同CT值范围确定患者肺体积、靶体积(GTV、CTV、PTV)是否从肺体积中减除及不同分割剂量为影响因素,计算肺剂量体积参数受影响的程度.结果 当CT值在-300～ -980至-500～ -980范围变化时,全肺体积减少的中位数为-9.10%,明显高于V30、V20、V10和MLD的中位变化(为-3.18%、-1.13%、0.82%和-0.79%).CT值-400～ -980确定的全肺体积随减除靶体积的增加V30、V20、V10和MLD的变化也加大,其中V30变化最大,V10变化最小.5例PTV体积＜140 cm3(中位PTV体积为78 cm3)患者设置总物理剂量60 Gy,分割剂量由2 Gy增加至10 Gy时,由物理剂量转换为生物等效剂量的V30、V20、V10和MLD逐渐增加(呈正相关),且三者变化相同(增加幅度约为40%).在＞6Gy分割剂量后,MLD变化更大(36%).结论 不同CT值范围勾画并确定肺体积时,对全肺体积影响最大,V30变化有统计学意义(尚不足以左右放疗计划的取舍),V20、V10和MLD的变化无统计学意义.全肺体积减去与之相重叠的靶体积(GTV、CTV、PTV)后,V30的变化最大,而影响最小的是V10.增加分割剂量也明显增加剂量体积参数,而剂量分割方式在3个因素中似乎影响最大(＞10%).     

Reassessment of parameters for applying motor-unit triggered stimuli in peri-stimulus time histograms

We reassessed the response properties of peri-stimulus time histograms (PSTHs) in cases when a test stimulus was triggered by a motor-unit discharge with a constant delay time. In this experiment, single motor unit action potentials were recorded from the right tibialis anterior (TA) muscle of five healthy persons. A test stimulus of the common peroneal nerve with low intensity to activate only Ia afferents of the TA was applied through a bipolar stimulating electrode placed distal to the neck of the fibula. We obtained several PSTHs with various delay times and stimulus intensities in the same recording session for maintaining the background property as the same among the test situations. As a result, we confirmed three characteristics of PSTHs from observed data: (1) given the same delay time (the same background firing properties), a weaker stimulus intensity evokes a lessened effect on PSTHs, naturally; (2) delay time alters the induction balance of direct and indirect effects on PSTHs even if the stimulus intensity is the same because the background firing properties are different; and (3) response probabilities do not correspond directly to stimulus intensities when background firing properties are different; it is possible for a relatively strong intensity stimulus to produce a weaker effect than a weak stimulus. We concluded that comparisons of effects taken at different phases in the control distribution (and also effects taken from different control distributions or different motor units) can be misleading. Therefore, such comparisons should only be made within data obtained from the same phase in the same control distribution of the same motor unit.     

Whole brain apparent diffusion coefficient histogram: a new tool for evaluation of leukoaraiosis

PURPOSE: To test whole brain apparent diffusion coefficient histogram analysis as an alternative approach to visual score for the assessment of leukoaraiosis (LA). MATERIALS and METHODS: T2 and diffusion weighted images were obtained in 15 elderly patients. LA extension was assessed on T2 weighted images by two observers using a semiquantitative visual score. Apparent diffusion coefficient (ADC) maps of the entire brain were generated and, after exclusion of the skull with manual tracing and of the cerebrospinal fluid (CSF) by application of a threshold value, whole brain (WB)-ADC histogram was obtained. Moreover, a brain volume index (BVI) was calculated on ADC maps as (intracranial volume - CSF volume) /intracranial volume. RESULTS: The kappa inter-observer agreement for LA scoring was 0.69. Manual segmentation of the skull showed a mean inter-operator coefficient of variation below 3%. The median value of whole brain ADC histogram directly correlated with LA extension (P = 0.013). Moreover a significant inverse correlation (P = 0.002) was found between WB-ADC median value and BVI. CONCLUSION: WB-ADC histogram is a reproducible alternative tool for assessing LA extension and severity.     

图像的阈值分割及其应用

目的 对被检测物体和背景反差较大的图像进行分割。方法 首先绘出要分割图像的灰度直方图；根据直方图选出适当的阈值；最后利用所选定的阈值对图像进行分割。结果 阈值法能把被检测物体和背景反差较大的图像分割。结论 对于被检测物体和背景反差较大的图像，阈值法是一种简单、有效、可靠的分割方法。     

三维适形放疗对Ⅲ期非小细胞肺癌肺功能影响的初步观察

目的 探讨Ⅲ期非小细胞肺癌三维适形放疗前后肺功能、DVH参数与放射性肺炎发生程度的关系。方法 71例未手术的肺癌患者，男52例，女19例，中位年龄63岁，KPS评分≥80。三维适形放疗前、后1、3个月检查患者肺功能，并观察其放射性肺炎的发生及程度，同时在DVH中得出V20、V30、MLD值。结果 所有患者均完成放疗，剂量为66～70Gy。放射性肺炎发生率为30％，2、3级以上为7％。V20、V20、MLD平均值越大，放射性肺炎程度越高。V20、V30及MLD与CLCO疗前和疗后1、3个月变化及疗后1个月和疗后3个月变化均有相关关系。结论放疗前后肺功能变化、DVH参数和放射性肺炎程度间存在一定相关关系。放疗后1个月与放疗前CLCO数值变化能更好地预测放射性肺炎发生几率；V20、V30、MLD除了与放射性肺炎发生程度相关外，也与放疗前后CLCO、FEV1的变化有关。