Arm skin water assessed via 300 MHz tissue dielectric constant (TDC) - - PowerPoint PPT Presentation

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Arm skin water assessed via 300 MHz tissue dielectric constant (TDC) - - PowerPoint PPT Presentation

Mar 13, 2024 183 likes •360 views

Arm skin water assessed via 300 MHz tissue dielectric constant (TDC) measurements: Dependence on total body water, fat and arm muscle mass R. Desfor and H.N. Mayrovitz mayrovit@nova.edu Nova Southeastern University Background Skin TDC values

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Arm skin water assessed via 300 MHz tissue dielectric constant (TDC) measurements: Dependence on total body water, fat and arm muscle mass

  • R. Desfor and H.N. Mayrovitz

mayrovit@nova.edu Nova Southeastern University

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Background

  • Skin TDC values depend on free and bound

water in the tissue

  • TDC values have been used to help detect

lymphedema associated with breast cancer treatment and to evaluate other edematous conditions

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Unilateral lymphedema

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Unilateral lymphedema

  • When only one arm is affected, we have a

normal arm to use as a control

  • These TDC arm ratios can be used to screen

patients who may be at risk for developing lymphedema

  • TDC arm ratios are not helpful for bilateral

cases

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Bilateral lymphadema

  • How do we evaluate a patient

without a “control” limb?

We must use absolute TDC values

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What parameters are quantifiably linked to TDC values?

  • We believe that tissue water likely varies with

total body fat and water

  • Until now, there has been no systemic

determination of possible TDC dependencies

  • n percentages of total body water (TBW%),

total body fat (FAT%), arm muscle mass (MM)

  • r percentage arm fat (FATARM%)
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Methods

SUBJECTS:

  • 30 male and 30 female adult seated subjects
  • Age 28.0 ± 9.8 years
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Measurements:

  • Bilateral anterior forearm and bicep TDC

measurements to depths of 1.5 and 2.5 mm below the epidermis to determine tissue water

MoistureMeterD: Small 1.5 mm probe Medium 2.5 mm probe

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Ironman Innerscan Bioimpedance Scale used to determine TBW%, MM%, FAT% and FATARM%

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TBW% vs. FAT%

20 30 40 50 60 70 80 10 20 30 40 50 60 70 80

FAT% TBW% TBW% = ‐0.643(FAT%) + 70.5 N = 65 R = 0.984

Results

Inverse relationship between TBW% and FAT%, as expected

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Results

  • TDC values at forearm and biceps are most

strongly positively correlated to MM% at forearm and bicep and are significantly negatively correlated to FATARM%.

  • TDC values are positively correlated with

TBW% and negatively correlated to FAT%

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Results

  • Strongest correlations were for forearm 1.5

mm depth TDC values yielding linear regression equations:

  • TDC= 0.465 (TBW%) + 7.94 (r=0.700)
  • TDC= ‐0.319(FAT%) + 41.2 (r=0.736)
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Forearm TDC AT 1.5 mm Depth

20 25 30 35 40 45 20 30 40 50 60 70 80

TBW% TDC

TDC = 0.471(TBW%) + 10.3 N = 65 R = 0.661

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Forearm TDC AT 1.5 mm Depth

20 25 30 35 40 45 10 20 30 40 50 60 70 80

FAT% TDC

TDC = ‐0.286(FAT%) + 40.1 N = 65 R = 0.693

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Conclusions

When absolute TDC values are needed, our findings provide a basis to individualize TDC reference values using a patient’s body habitus, including their TBW% and FAT%

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Questions?