Application of wavelet transform and bio-impedance technique in gastric motility
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Abstract

AIM：To investigate the method of extracting gastric motility information with wavelet transform and bio-impedance technique.

METHODS： The experiment was carried out in the Institute of Biomedical Engineering, Chongqing University of Posts and Telecommunications between July and October in 2006.①Twenty-four male volunteers aged 20－21 years were examined normal in gastric motility and were adopted in this experiment. Gastric emptying detection was performed with four probe method in bio-impedance technique after the testees were fasted for 8 hours and then drank 400 mL purified water (37 ℃).②The wavelet transform was addressed to deal with the noised body surface bio-impedance signal, in which the dbN was used to decompose the signal into multi-resolution analysis and reconstruct it on selected ones. Gastric impedance signal was obtained by eliminating the respiration impedance and blood impedance.

RESULT: All of the 24 subjects completed the test and entered the result analysis. The base impedance characteristic held the line before drinking, and stepped up after drinking, then decreased quickly, at last slow-moving stepped down. The half time of gastric empting was (8.78±1.76) minutes. The frequency scope of gastric impedance by reconstructing with the wavelet transform was ranged 2－4 counts per minute. The smooth surface was beneficial for the removal of respiration and blood impedance signal.

CONCLUSION:①Though the gastric impedance is influenced by many factors, such as gastric secretion and components of test meal, there is a corresponding relation between impedance curve and gastric perfusion by selecting non-nutrient and low-electrical conductivity solid, which provides a non-invasive method to investigate surface gastric emptying function in clinic.②Because of the identical frequency consistency of gastric impedance reconstructed by wavelet transform and gastric motility, we can use the mechanical feature to analyze and evaluate the function of gastric motility, and avoid the inaccurate judgment to the gastric function disorder through surface electrogastrography.

Wang W, Li ZY, Ren CS.Application of wavelet transform and bio-impedance technique in gastric motility information.Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu 2007;11(13):2434-2436(China)
[www.zglckf.com/zglckf/ejournal/upfiles/07-13/13k-2434(ps).pdf]

摘要
目的：探索基于小波变换和阻抗技术提取胃动力信息的方法。
方法：实验于2006－07/10在重庆邮电大学生物医学信息工程研究所实验室完成。①选择胃动力正常的男性志愿者24名（年龄20～21岁），空腹8 h后喝纯净水400 mL（水温37 ℃），利用阻抗技术的四电极法进行胃排空检测。②运用小波变换方法结合Daubechies小波系对体表阻抗信号进行多分辨分析和重构，滤除呼吸阻抗和血流阻抗，进而获得胃阻抗信号。
结果：24名被试均完成测试进入结果分析。被试具有喝水前基础阻抗不变，喝水后阻抗升高，然后快速下降再缓慢下降的特点，400 mL纯净水的半排空时间为（8.78±1.76） min。利用小波变换对体表阻抗信号重构后获得的信号频率范围在2～4次/ min，表面光滑，有效去除了呼吸阻抗和血流阻抗信号。
结论：①尽管胃阻抗受到胃酸分泌、试餐成分等多种因素的影响，但选用电导率低的无营养液体仍可获得阻抗曲线和胃容积变化的对应关系，为胃排空功能研究提供一种新的体表无创检测途径。②利用小波变换重构的阻抗信号频率与健康人胃蠕动节律一致，可以对胃蠕动功能从机械特性角度进行分析和评价，从而避免了胃电信号不能准确判断胃蠕动等机械活动失常所引起的胃动力紊乱。
关键词：小波变换；生物阻抗；胃动力；胃排空

王伟，李章勇，任超世.小波变换和阻抗技术在胃动力研究中的应用[J].中国组织工程研究与临床康复，2007，11(13):2434-2436
[www.zglckf.com/zglckf/ejournal/upfiles/07-13/13k-2434(ps).pdf]