Vonk Noordegraaf A, Kunst P W, Janse A, Smulders R A, Heethaar R M, Postmus P E, Faes T J, de Vries P M
Department of Pulmonary Medicine, University Hospital Vrije Universitait, Amsterdam, The Netherlands.
Med Biol Eng Comput. 1997 Mar;35(2):107-12. doi: 10.1007/BF02534139.
The Sheffield electrical impedance tomography; (EIT) system produces images of changes in the distribution of resistivity within tissue. The paper reports on the application of electrical impedance tomography in monitoring volume changes in the limb during venous occlusion. The aim of the study is to assess the feasibility, reproducibility and validity of calf blood flow measurements by EIT. In 14 healthy volunteers calf blood flow is compared, as determined in a calf segment by strain-gauge plethysmography (SGP), with the impedance changes measured by EIT during rest and post-ischaemic hyperaemia. The measurements are repeated to assess reproducibility. The reproducibility for the EIT, assessed from the repeated measurements and expressed as a reproducibility coefficient, is 0.88 during rest and 0.89 during hyperaemia. The reproducibility coefficient for SGP data is 0.83 at rest and 0.67 during hyperaemia. Flow measurements, assessed by means of two methods, correlate well at rest (r = 0.89), but only moderately during hyperaemia (r = 0.51). The correlation coefficient for the pooled flow measurements is 0.98. It is concluded that EIT is a valid and reliable method for assessing blood flow in the limb. Possible applications of EIT in localising fluid changes are discussed.
谢菲尔德电阻抗断层成像（EIT）系统可生成组织内电阻率分布变化的图像。本文报道了电阻抗断层成像在监测静脉阻塞期间肢体体积变化中的应用。本研究的目的是评估通过EIT测量小腿血流量的可行性、可重复性和有效性。在14名健康志愿者中，将通过应变片体积描记法（SGP）测定的小腿节段血流量，与EIT在静息和缺血后充血期间测量的阻抗变化进行比较。重复测量以评估可重复性。根据重复测量评估的EIT可重复性，以可重复性系数表示，静息时为0.88，充血时为0.89。SGP数据的可重复性系数在静息时为0.83，充血时为0.67。通过两种方法评估的血流量测量值在静息时相关性良好（r = 0.89），但在充血时仅为中等程度相关（r = 0.51）。合并血流量测量值的相关系数为0.98。结论是，EIT是评估肢体血流量的一种有效且可靠的方法。还讨论了EIT在定位液体变化方面的可能应用。
