These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Monitoring water content of rat lung tissue in vivo using microwave reflectometry.
    Author: Schaefer M, Nowak K, Kherad B, Gross W, Post S, Gebhard MM.
    Journal: Med Biol Eng Comput; 2004 Sep; 42(5):577-80. PubMed ID: 15503956.
    Abstract:
    Measurement of lung water is an important diagnostic means of assessing pulmonary oedema. Water content affects the dielectric spectrum at microwave frequencies, but quantification is still a problem. A new lung tissue model is presented that allows the calculation of water content from dielectric permittivity. The dielectric permittivity of lung tissue was measured by microwave reflectometry using a non-invasive surface probe. During perfusion of rat lungs (n = 22) with blood, injury was induced by interruption of the blood supply for a duration between 0 (control) and 2 h. Water content was assessed from dielectric permittivity using a new mixture formula and was also determined by drying and weighing. The mixture formula allows for the dielectric polarisation of water, dry matter and air in the tissue. A linear correlation was found between total water content determined from dielectric permittivity and that from drying and weighing (y= 1.001x, R2 = 0.8). Lung injury showed an increase in total water content from 80.9 +/- 1.2% (control) to 84.1 +/- 0.9% (p < 0.01). The analysis of dielectric permittivity data at microwave frequencies with the new tissue model is sensitive enough to detect water accumulation produced by lung injury and it can be used to monitor total water content without tissue destruction.
    [Abstract] [Full Text] [Related] [New Search]