Heart rate variability during extracorporeal membrane oxygenation and recovery in severe neonatal disease

BACKGROUND: Heart rate variability (HRV) reveals information on the functional state of the autonomic nervous system (ANS) in neonates. During severe illness, heart rate variability is impaired. AIM: This study was initiated to measure the changes in HRV in neonates during extracorporeal membrane oxygenation (ECMO) and recovery from severe respiratory and circulatory failure. Moreover, we compared our data with HRV data of healthy newborns and we investigated the differences in HRV parameters between ECMO-survivors and non-survivors. STUDY DESIGN: This study is of an observational character. We performed short-term recordings of heart rate variability in 14 neonates during ECMO and recovery. We computed time- and frequency-domain HRV parameters. RESULTS: ECMO significantly affects time-domain HRV parameters. Severe neonatal illness causes a significant reduction of all calculated HRV parameters; clinical recovery is accompanied by an increase of HRV. In comparison with normative data of healthy newborns, however, HRV remains impaired. The ECMO-development ratio separated the non-survivors from the survivors during ECMO therapy. CONCLUSIONS: During severe neonatal illness, HRV is impaired. It remains to be clarified whether the impairment of HRV during severe illness can predict the neurological outcome. The ability of the E/D ratio as an HRV parameter to serve as a predictive tool has to be corroborated in larger group of patients.     

特发性全面强直阵挛发作型癫^1H-MRS与DWI的初步研究

目的：分析丘脑、岛叶、基底核区的代谢物和水分子弥散异常在特发性全面强直阵挛发作型癫（PGTCS）发病中的意义。方法：对30例PGTCS患者（PGTCS组）进行发作间期的MRS采集,半定量分析丘脑、岛叶、基底核区的NAA、Cho、Cr;用NHS3量表对病情程度进行量化评分,计算NAA/Cr值、NAA/（Cho＋Cr）值与癫严重程度的相关性;行DWI检查,观测相应兴趣部位的ADC值的变化;设对照组30例与之比较。结果：与对照组比较,PGTCS组双侧丘脑NAA/Cr值、NAA/（Cr＋Cho）值均明显降低（P0.05）,而双侧基底核区、岛叶NAA/Cr值、NAA/（Cr＋Cho）值无明显变化;PGTCS组双侧丘脑NAA/Cr值、NAA/（Cr＋Cho）值与NHS3量表评分呈负相关;PGTCS组双侧丘脑、岛叶、基底核区ADC值均明显高于对照组,具有统计学意义（P0.05）。结论：PGTCS患者丘脑存在神经元丧失及胶质细胞增生,提示丘脑可能为发作间期癫形成的相关脑区,或是长期癫发作的脑损伤区;1H-MRS能较准确地反映PGTCS患者发作造成的脑损伤;DWI能敏感地反映PGTCS癫发作间期存在水分子弥散增加的病理生理改变。     

前列腺癌扩散加权成像与Gleason评分的相关性研究

目的 探讨前列腺癌肿瘤ADC值的变化与病理Gleason评分的关系.方法 对经穿刺活检证实的65例前列腺癌患者行磁共振扩散加权成像检查,b值800 s/mm2.根据病理结果 将前列腺外周带六分区归类为癌区和非癌区,测量每个分区的ADC值,癌区与非癌区之间行ROC分析,并与病理Gleason评分进行对照.结果 65例前列腺癌的癌区和非癌区ADC值分别为(1.19±0.30)×10-3 mm2/s和(1.79±0.34)×10-3 mm2/s,差异有统计学意义(t=17.74,P＜0.01);ROC曲线上临界点取1.44×10-3 m2/s,诊断的敏感性达84.30%,特异性为64.00%.癌区ADC值与Gleason评分呈负相关(r=-0.347,P＜0.01).结论 前列腺癌癌区ADC值与Gleason评分呈负相关;ADC值有可能用于评价前列腺癌的分级和预后.     

味觉刺激弥散加权成像评价正常涎腺功能

目的 探测MR弥散加权成像(DWI)是否能记录味觉刺激时涎腺弥散系数(ADC)值的变化,并观察味觉刺激前后ADC值的变化. 方法 对17名健康志愿者行1.5T MR检查.DWI序列于静息时采集1次,给予含化维生素C片500 mg之后30 s至23 min左右连续采集.由DWI得到刺激前后涎腺的ADC值,采用重复测量方差分析比较刺激前后的差异. 结果静息状态颌下腺ADC值(1.26±0.11)×10~(-3) mm~2/s高于腮腺(1.00±0.09)×10~(-3) mm~2/s(P<0.01).在酸刺激最初的 2 min(0.5～4.5 min)腮腺ADC值[(1.08±0.10)×10~(-3) mm~2/s]显著升高(P<0.01),颌下腺ADC值[(1.27±0.15)×10~(-3) mm~2/s]稍升高(P=0.71);之后的7 min(2.5～8.5 min)腮腺ADC值[(0.09±0.01)×10~(-3) mm~2/s]和颌下腺ADC值[(1.11±0.12)×10~(-3) mm~2/s]明显下降(P<0.01);之后的9 min ADC值逐渐上升,至16 min(10.5～22.5 min)达高峰.腮腺[(1.13±0.09)×10~(-3) mm~2/s]明显高于基线值(P<0.01),颌下腺[(1.34±0.11)×10~(-3) mm~2/s]轻度提高(P=0.02). 结论 DWI可以无创地评价涎腺功能变化,味觉刺激后ADC值显示出三个阶段的变化,可能对早期发现涎腺功能改变起到一定的作用     

前置胎盘伴胎盘植入的磁共振诊断价值

目的 探讨磁共振成像对前置胎盘伴胎盘植入的诊断价值。 方法 回顾性分析笔者医院34例因前置胎盘伴阴道流血入院孕妇,均行磁共振T₂WI和DWI扫描,结果经手术及病理证实。测量植入与非植入性胎盘组织的表观弥散系数(ADC),分析T₂WI、DWI序列及两者联合诊断胎盘植入的价值。 结果 34例中,胎盘植入18例。植入性胎盘中植入与非植入部位及非植入性胎盘组织ADC值差异有统计学意义(P值分别为0.000、0.032)。T₂WI和DWI序列及两者联合诊断胎盘植入的敏感度、特异性分别为83.3%、87.5%,66.7%、62.5%和94.0%、63.0%。 结论 DWI对胎盘植入定性及定量诊断有一定参考价值。磁共振T₂WI联合DWI序列可提高诊断胎盘植入的敏感度,减少漏诊率,增加诊断信息。     

超声背散射系数评价松质骨状况的可行性研究

目的研究超声背散射信号及其背散射系数（backscatter coefficient,BSC）评价松质骨状况的可行性。方法首先建立了一种蜂窝状的松质骨理论模型,然后将BSC与频率的理论关系和牛胫骨松质骨实验结果进行了比较;最后实验分析了BSC与松质骨表观密度的关系。结果松质骨中超声BSC随入射频率的增加而非线性的增加,理论模型和实验结果是一致的。随松质骨表观密度的增大,BSC增大。结论在用超声评价松质骨状况时,背散射信号具有重要作用,其BSC可用于评价松质骨状况。     

Reproducibility of visual assessment on mammographic density

Background High mammographic density was an independent risk factor for breast cancer and has a higher associated risk than most other known risk factors. The reproducibility remains a major issue in assessment of breast parenchymal patterns. Misclassification of mammographic pattern can lead to significant underestimation of risk estimates. The purpose of this study was to assess the inter-rater and intra-rater reliability based on visual subjective mammographic density measurements. Method Three density measures, Wolfe parenchymal pattern, Boyd classification scale, and a percentage of densities in total breast, were investigated. The study included 101 women who were participants of the International Breast Cancer Intervention Study I (IBIS I) for up to 7 years. Seven sets of mammograms were collected for each woman. Left breast mediolateral oblique films were digitized, and the scanned images were independently reviewed by two readers. These images were reassessed by one reader after a year. The agreements of measures were evaluated by Kappa statistics (Wolfe and Boyd scale) and intraclass correlation coefficient (percentage densities). Results For the inter-rater agreement, Weighted Kappa for Wolfe scale was 0.89 (P < 0.0001) and for Boyd scale was 0.84 (P < 0.0001). The intraclass correlation coefficient was 0.94 for percentage densities. For the intra-rater agreement, Weighted Kappa for Wolfe scale was 0.87 (P < 0.0001) and for Boyd scale was 0.86 (P < 0.0001). The intraclass correlation coefficient was 0.96 for percentage densities. Conclusion The study concludes that both visual qualitative and quantitative measurements on mammographic density are highly reproducible in the breast cancer research studies if appropriate training is provided. The method is appropriate for risk assessment in a prevention trial.     

组织模体比对X射线中心轴剂量特性的研究

目的：提出一种用于描述高能X射线中心轴剂量特性的数学模型,并且给出一种用于计算临床组织模体比（TPR）表的方法。方法：分别对6,18和24MV X射线的实测TPR数据与深度和照射野之间的关系进行二阶指数线性回归分析,推导出描述TPR值随深度和照射野变化的数学模型,通过对模型的计算结果与实测数据之间的误差分别来评价模型精度,并给出确定模型参数所需的最少实测数据。结果：只需TPR数据即可确定由5个参数构成的二阶指数模型,其参数均与辐射质指数线性相关,对应6,18和24MV X射线,使用该模型计算的TPR数据表与实测表的误差分别在1．5％,1．2％,和1．1％之内,并可同时求得描述原射线中心轴剂量特性的2个主要指标：衰减系数（μ）和硬化系数（η）。结论:该模型建立了一种从有限实测数据得出临床TPR数据表的有效方法,可用于对X射线中心轴剂量特性的数学描述。     

肾代谢系统的仿真研究

对复杂的肾代谢系统进行简化,并建立其数学模型。在此模型上借助MATLAB软件,对不同的肾功能的代谢过程进行仿真,模拟肾的代谢过程,探讨其规律,据此对复杂肾代谢系统给出合理的解释。