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Figures for the article ”MoistureMeterD and…” Tapani Lahtinen.

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Presentation on theme: "Figures for the article ”MoistureMeterD and…” Tapani Lahtinen."— Presentation transcript:

1 Figures for the article ”MoistureMeterD and…” Tapani Lahtinen

2 Lymphedema: Where is tissue swelling? 1. Edema according to surface area = 1.16 (16%) 2. Edema according to circumference= 1.08 (8%) 3. Edema in muscle mass= 1.07 (7%) 4. Edema in subcutaneous fat= 1.36(36%) 5. Edema in skin (not seen here)  Measure superficially! Preclinical and early lymphedema: Skin MoistureMeterD measurement Fig. 1

3 Fig. 2 Multiprobe MoistureMeterD MoistureMeterD Compact

4 Concept of Free and Bound (or Motionally restricted) Water in Tissue Proteins and macromolecules with high surface charge Two or three layers of tightly bound water molecules Free water molecules In human skin 50- 60% of tissue water is bound! Fig. 3

5 MoistureMeterD devices – Operation principle High-frequency electromagnetic field (300 MHz) is induced in tissue EM field penetration is dependent on the probe size A part of EM energy is absorbed by tissue water From the reflected wave information the tissue dielectric constant (TDC) is calculated Tissue dielectric constant is directly proportional to tissue water content Fig. 4

6 Calibration of the dielectric measurement with mixtures simulating water and solid components in the skin Five different mixtures measured with the MoistureMeter D (percentage water volume content, V%) V =0 % (pure ethanol, DC = 22) V =25% V =50% V =80% V =100% (pure water, DC = 78) (1)A water component with a high dielectric constant DC (2)A solid component with a low dielectric constant DC (ethanol) Model: water ethanol mixtures Fig. 5

7 Validation of the dielectric measurements During hemodialysis treatment where interstitial fluid was removed the TDC of skin and subcutis was measured: TDC From: Nuutinen J., Ikäheimo R. and Lahtinen T. Validation of a new dielectric device to assess changes of tissue water in skin and subcutaneous fat Physiol. Meas. 25: 447-454, 2004 Fig. 6

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