Compilation of recent publications on tissue dielectric constant (TDC)

Tissue dielectric constant (TDC) is increasingly being recognised as an important tool for lymphoedema assessment and management. The following is a compilation of research, although not exhaustive, on this assessment tool.

Date range: December 2009 to March 2021

General properties

Title: Effects of Local Forearm Skin Heating on Skin Properties.

Authors: Mayrovitz HN.

Publication: Clinical Physiology and Functional Imaging 2020 Vol 40(5) p369-376.

Abstract

This study investigated impacts of local skin heating on skin properties and tested whether skin changes depended on heat-induced hyperaemia. It was reasoned that heat-induced vasodilation impacts accompanying interstitial fluid changes. Forearm skin was locally heated from a baseline of 35°C to 40–42°C in 30 young adults (15 females, 15 males, 24.9 ± 2.1 years) and non-heated in 10 others (5 females, 5 males, 25.2 ± 1.3 years. Skin blood flow (SBF) was continuously measured using a laser Doppler method and skin tissue dielectric constant (TDC), stratum corneum capacitance (SCC) and transepidermal water loss (TEWL) were measured before and after maintained heat for 12 min. TDC values were determined to effective measurement depths of 1.5 mm (TDC15) and 2.5 mm (TDC25). Results showed a large heat-induced hyperaemia, with SBF increasing on average 8.8-fold from its baseline of 35°C. Heating also caused significant increases in TDC, SCC and TEWL that, compared to preheating, increased approximately 1.1-fold, 3.1-fold and 4.5-fold. None of these skin changes correlated with the magnitude of the SBF hyperaemic response. Absence of this correlation may indicate that in young healthy adults, increased capillary filtration due to heat-induced arteriolar vasodilation is rapidly accommodated by postcapillary reabsorption, enhanced lymphatic activity and TEWL processes. An alternate explanation is that heating caused increased red cell oscillations that were detected as part of the laser Doppler increase without representing increased capillary flux. The major determinant of the Increases in TDC, SCC and TEWL is likely a consequence of heat-induced eccrine gland activation. Studies of older persons or those with depressed function are warranted.

Title: Heat‐Related Changes in Skin Tissue Dielectric Constant (TDC)

Authors: Mayrovitz HN, Berdichevskiy G, Lorenzo‐Valido C, Fernandez M.

Publication: Clinical Physiology and Functional Imaging 2020 Vol 40 (5) p369-376.

Abstract

The impact of 20 min of whole-body heating (WBH) on the tissue dielectric constant (TDC) of forearm and hand skin was evaluated in 24 young adults. TDC was measured in triplicate at 300 MHz using an open-ended transmission line method in which the effective measurement depth was about 2 mm. TDC measurements are an effective way to assess and track localized oedema and lymphoedema. The underlying hypothesis was that heat-induced eccrine gland activation would increase TDC values via an increase in fluid within the TDC measurement volume. The goal was to test this concept and to determine the magnitude of the change when environmental temperatures were elevated to near 42°C and to estimate TDC recovery time. The practical aspect of this research is motivated by the fact that patients in whom such measurements are made may arrive at the clinic in various states of sweat gland activation. Thus, knowledge of the effect of such activation on measured TDC values permits better understanding of possible relationships between such activation and TDC values. Results showed that increasing environmental temperature from 23·3 ± 1·6 to 41·5 ± 1·3°C increased forearm and thenar eminence skin temperatures to 37·8 ± 0·5 and 37·9 ± 0·4°C, respectively. These changes were associated with increases in TDC at arm from 30·7 ± 4·6 to 36·3 ± 5·7 (18·2%) and at hand from 34·7 ± 4·9 to 45·1 ± 5·5 (30%). Based on calculated TDC recovery rates, it is concluded that temperature related TDC variability can be minimized using a wait time of at least 15 min after bandage removal prior to TDC measurements in affected limbs.

Title: Skin Tissue Dielectric Constant in Women With High Body Fat Content.

Authors: Mayrovitz HN, Forbes J, Vemuri A, Krolick K, Rubin S.

Publication: Skin Res Technol. 2020 Vol 26(2) p226-233.

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Abstract

Background: Skin tissue dielectric constant (TDC) measurements at a frequency of 300 MHz are used to assess skin properties in many conditions. Impacts of patient obesity on these values are unknown, and its quantitative assessment was the goal of this research.

Materials and methods: Women in a weight loss program (N = 32) had TDC measured on forearm, biceps, neck, jowl, and submental regions along with measurements of total body fat (TBF), water (TBW), intracellular water (ICW), and extracellular water (ECW) via multi-frequency bioimpedance. Group age (mean ± SD) was 40.0 ± 11.6 years (20-70 years) with body mass index (BMI) of 31.8 ± 6.7 Kg/m2 (23.0-49.9 Kg/m2 ). For analysis, subjects were divided into those with BMI < 30 Kg/m2 (subgroup A, n = 16) vs ≥30 Kg/m2 (subgroup B, n = 16).

Results: Tissue dielectric constant at forearm and biceps decreased significantly (P < .001) with increasing depth from 0.5 to 1.5 to 2.5 mm but TDC values and their inter-side ratios did not differ between subgroups A and B at any measured site. Although correlations between TBW, ECW, and ICW were significant (P < .001), there was no dependence of TDC values on any of these parameters. Conclusions: Previously unknown TDC values for obese persons are provided and based on subgroup analyses suggest that skin TDC values in overweight and obese persons are not confounded by variables such as TBW and TBF. Further, since inter-side ratios and their SD’s yielded thresholds for forearm and biceps similar to those established for women with normal BMI, use of these clinical inter-arm TDC ratios now is extended to include a wider BMI range.

Title: Assessment of Skin Properties in Chronic Lymphedema: Measurement of Skin Stiffness, Percentage Water Content, and Transepidermal Water Loss.

Authors: Yu Z, Liu N, Wang L, Chen J, Han L, Sun D.

Publication: Lymphatic Research Biology 2020 Vol 18(3) p212-218.

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Abstract

Background: Lymphedema (LE) is a chronic progressive protein-rich edema of the soft tissues. Measurement of extracellular fluid of the affected limbs is widely used in detecting LE; however, quantification of the skin alterations and early tissue changes in LE lacks approaches.

Methods and Results: Ninety-one patients with LE were assessed. Measurement of transepidermal water loss (TEWL), skin stiffness (SF), and percentage water content (PWC) was assessed on five predetermined skin sites. The value of TEWL, SF, and PWC increased significantly in lymphedematous skin compare with controls, indicating damaged function and texture of the affected skin. Both PWC ratio and SF ratio strongly correlated with LE stage. High correlations were found among instruments assessing tissue fluid.

Conclusions: Assessment of the skin parameters has contributed new information about the functional and structural alterations in chronic lymphedematous skin. Quantification of skin properties changes could be a valuable supplement to diagnosis and evaluation of chronic LE.

Full article available

Title: Minimum Detectable Changes Associated with Tissue Dielectric Constant Measurements as Applicable to Assessing Lymphedema Status.

Authors: Mayrovitz HN, Mikulka A, Woody D.

Publication: Lymphatic Research and Biology 2019 Vol 17(3) p322-328.

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Abstract

Background: Tissue dielectric constant (TDC) measurements are increasingly being used as a tool to help characterize lymphedema features, detect its presence, and assess treatment related changes. Although the underlying physics of this technology has been well described in the literature, there has been little systematic study of in vivo reliability aspects. A central unanswered question is the minimal detectable change (MDC) that, with a given level of confidence, may be ascribed to this technology. Our goal was to address this issue using test-retest measurements from which intraclass correlations coefficients (ICC) and MDC could be estimated.

Methods and Results: Forty volunteers (20 females) aged 19-61 years with body mass indices of 14.7-47 kg/m2 and body fat percentages of 12.0%-48.9% were evaluated. Two measurers (M1 and M2) used two different TDC measuring devices (multiprobe and compact) to measure TDC in triplicate sequentially and bilaterally at three locations; anterior forearm, hand palmar mid-thenar eminence, and dorsum mid-web. These measurements were made by each measurer twice constituting test-retest values (T1 and T2). From these measurements ICC2,1 and MDC at 95% confidence were determined for each site and probe for absolute TDC values and for inter-side ratios. MDC values for absolute TDC ranged from 2 to 9 TDC units, and for inter-side ratios ranged from 5.3% to 8.0% depending on site and probe. ICC2,1 values ranged from 0.765 to 0.982.

Conclusions: The MDC values herein documented may be used to provide guidance to aid interpretation of measured TDC changes or differences in a clinical environment.

Full article available

Title: Assessing Upper and Lower Extremities Via Tissue Dielectric Constant: Suitability of Single Versus Multiple Measurements Averaged

Authors: Harvey N. Mayrovitz

Publication: Lymphatic Research and Biology, 2018

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Abstract

Background: Tissue dielectric constant (TDC) measurements as an index of local tissue water are useful in a range of applications most notably to characterize and assess lymphedema. Once a measuring device is applied to skin and a result is obtained in less than 10 seconds, but multiple sites may be required and use of the standard triplicate measurements may be time prohibitive. Thus, this study’s goal was to provide data from which informed judgments could be made as to the impact of making a single measurement to reduce expended clinic time.

Methods and Results: Sixty subjects (30 female) were recruited with an average age (mean–standard deviation) of 30.6–13.4 years. TDC was measured in triplicate bilaterally at forearm, hand palm, lateral calf, medial calf, and foot dorsum. The agreement in absolute TDC values and interside ratios was evaluated for assessments made using only the first TDC measurement, the average of duplicates and the standard triplicate. Results showed that differences between single and multiple measurement averages were anatomical site dependent with the smallest coefficient of variation (2.19%) at the forearm and the largest at the lateral calf (4.59%).

Conclusions: Results suggest that when clinical time is of major concern, useful TDC data may be obtained in upper limbs using single TDC measurements per anatomical site whereas lower extremity skin assessments should be done using at least duplicate and preferably triplicate measurements. However, as with all such time reliability considerations, clinical judgment should be exercised and aided by the various findings of this study.

Full article available

Title: Suitability of Single Tissue Dielectric Constant Measurements to Assess Local Tissue Water in Normal and Lymphedematous Skin.

Authors: Mayrovitz HN, Davey S, Shapiro E. Clinical

Publication: Physiology and Functional Imaging 2009 Vol 29(2) p123–127.

Abstract

Previous reports described the use of average tissue dielectric constant (TDC) measurements to assess local tissue water and its change. Our goal was to determine if a single TDC measurement could be used in place of the average of multiple measurements. The comparison criteria used to test this was the extent to which single and averaged measurements yielded similar TDC values in both normal and lymphedematous tissue. Measurements were made in two groups of women; a control group (n = 20) and a group with unilateral arm lymphedema (n = 10). In the control group, TDC was measured to multiple depths (0·5–5·0 mm) on both ventral forearms and to a depth of 2·5 mm on the lateral thorax on both body sides. In the lymphedematous group, TDC was measured on both ventral forearms to a depth of 2·5 mm. Results showed that the 95% confidence interval for differences between single and averaged TDC values was less than ±1 TDC unit and that the limits of agreement between methods was less than ±2·5 TDC units (±6·5%) for each condition, site and depth measured. This finding suggests that where this level of agreement is acceptable suitable clinical assessments can be made using a single TDC measurement.

Head and neck

Title: An Approach Toward Assessing Head-and-Neck Lymphedema Using Tissue Dielectric Constant Ratios: Method and Normal Reference Values.

Authors: Mayrovitz, Patel, Kavadi, Khan and Bartolone

Publication: Lymphatic Research and Biology 2021 Published Online:2 Feb 2021 https://doi.org/10.1089/lrb.2020.0107

Abstract

Background: There are multiple methods to quantitatively assess limb lymphedema, but quantitative methods to assess external lymphedema in persons with head-and-neck lymphedema are quite limited. Quantification in this difficult condition currently uses multiple time-consuming head, face, and neck metric measurements, the accuracy of which is unclear. Thus, there is an important need for a new approach that is sufficiently convenient yet accurate to quantify head-and-neck lymphedema. The approach adopted was to use tissue dielectric constant (TDC) measurements that depend on tissue water, at neck and a submental area, and normalize these to TDC values at the forearm as a way to develop subject-independent indices.

Methods and Results: TDC was measured in 60 self-reported healthy nonlymphedematous adults (34 female, 18–81 years, 18.5–45.7 Kg/m2) at two neck sites and one arm site bilaterally and at a submental area. Neck-to-arm-index (NAI) and submental-to-arm-index (SAI) ratios were calculated. TDC values (mean ± standard deviation [SD]) for neck, submental, and arm were, respectively, 37.4 ± 6.9, 35.9 ± 7.7, and 30.1 ± 4.6. Mean NAI and SAI values were 1.253 ± 0.222 and 1.214 ± 0.296 respectively. Head-and-neck lymphedema thresholds calculated as mean + 2.5 SD were for NAI and SAI 1.80 and 1.95, respectively.

Conclusions: An approach to help quantify and track head-and-neck lymphedema using TDC neck and/or submental values normalized to a person’s forearm TDC values indicates threshold values between 1.80 and 1.95. These ratios, denoted as NAI and SAI, are suggested for use to detect and track changes in lymphedema status based on a patient’s changing indices associated with lymphedema treatment.

Title: Measuring Head and Neck Lymphedema: The ‘‘ALOHA’’ Trial.

Authors: Purcell A, Nixon J, Fleming J, McCann A and Porceddu S.

Publication: Head and Neck 2016 Vol 38(1) p79-84.

Abstract

Background: There is no clinical assessment available to measure head and neck lymphedema. This study proposes the use of a tape measurement system and the MoistureMeterD (MMD) to evaluate head and neck lymphedema.

Methods: The reliability and validity of these assessments was examined in 20 patients with head and neck lymphedema and 20 matched healthy controls.

Results: Interrater reliability for the MMD and 3 of the 4 tape measurements was excellent (intraclass correlation coefficients [ICCs] >0.90). Intrarater reliability of the MMD was 0.97. The MMD discriminated between patients with head and neck lymphedema and healthy controls, t(19) = 8.97, p < .001, whereas the tape measurements did not. Correlation between MMD score and head and neck lymphedema level ratings was significant (rho = 0.59) indicating convergent validity. Three of the tape measurements were significantly correlated with MMD scores (rho = 0.37-0.38) but not with ratings of head and neck lymphedema. Conclusion: The tape measurement system and MMD show potential as objective measurements of head and neck lymphedema with the exception of 1 tape measurement point.

Breast and torso

Title: Breast Tissue Dielectric Constant as a Potential Breast Edema Assessment Parameter.

Authors: Mayrovitz H, Somarriba, and Weingrad

Publication: Lymphatic Research and Biology 2021 Mar 24. doi: 10.1089/lrb.2020.0137. Online ahead of print.

Abstract

Background: Many methods can quantitatively assess limb lymphedema, but methods to assess breast edema/lymphedema are quite limited. Thus, there is a need for a convenient and accurate way to quantify and track changes in this condition. Herein, breast tissue dielectric constant (TDC) values that depend on tissue water were used to obtain reference TDC values and interbreast TDC ratios.

Methods and Results: TDC was measured in both breasts of 61 women who were about to undergo an ultrasound-guided diagnostic biopsy of a single mass (tumor) in 1 breast. Patient age and body mass index were (mean ± SD) 65.1 ± 11.6 (41-87 years) and 28.9 ± 5.1 (19.1-43.7 kg/m2). TDC was measured at a standardized site (12 o’clock position) with the TDC probe placed with its outer edge at the periphery of the subareolar region. TDC values of healthy breasts versus tumor breasts showed tumor breasts 3% greater (30.4 ± 4.6 vs. 29.5 ± 4.6, p = 0.02). Patients with benign tumors (N = 33) showed no difference between breasts (30.5 ± 4.4 vs. 30.8 ± 4.6 p = 0.434) and had an interbreast TDC ratio (tumor breast/healthy breast) of 1.013 ± 0.077. Patients with malignant tumors (N = 28) had tumor breast values 5% greater (29.8 ± 4.8 vs. 28.4 ± 4.6, p = 0.018) and an interbreast ratio of 1.056 ± 0.117. The overall interbreast ratio (N = 61) was 1.033 ± 0.099.

Conclusion: Breast TDC values from nonedematous breasts provide the basis for calculating potential edematous/lymphedematous threshold values based on the measured means +2.5 standard deviation (SD). Accordingly, a TDC threshold value of 41 and an interbreast ratio of 1.28 were determined. These parameters have potential applicability for early detection in at-risk patients and those suspected of having breast edema/lymphedema.

Title: Assessing Breast Lymphoedema Following Breast Cancer Treatment Using Indocyanine Green Lymphography.

Authors: Heydon‑White A, Suami H, Boyages J, Koelmeyer L, Peeble K.

Publication: Breast Cancer Research and Treatment 2020 Vol 181(3) p635-644.

Abstract

Purpose: Breast lymphoedema is a largely unrecognised survivorship issue for women following breast cancer treatment. While a few objective methods have previously been applied to assess breast lymphoedema, none are capable of imaging breast lymphatics or identifying lymphatic morphological changes indicative of breast lymphoedema. The purpose of this study was to determine if indocyanine green (ICG) lymphography, a validated assessment technique in breast cancer-related lymphoedema), can visualise breast lymphatics and identify breast lymphoedema. Additionally, ICG lymphography was utilised to investigate lymphatic drainage pathways of the affected breast following breast-conserving therapy.

Methods: Twenty female participants (10 breast lymphoedema and 10 healthy controls) were recruited for this pilot study. All underwent a medical history, physical breast assessment, tissue dielectric constant measures of breast water content, and ICG lymphography.

Results: ICG lymphography identified lymphatic morphological changes in all breast lymphoedema participants (dermal backflow patterns = 10, collateral lymphatic drainage = 9) and none in the control group. The dominant lymphatic drainage pathway to the ipsilateral axilla was observed in all control participants but in only four breast lymphoedema participants. Collateral drainage pathways in the breast lymphoedema group were to: parasternal (6/10); contralateral axilla (4/10); intercostal (3/10); and clavicular (2/10) regions.

Conclusion: These findings suggest ICG lymphography, through the identification of morphological lymphatic changes, is a potential qualitative objective assessment technique for breast lymphoedema. Furthermore, in this group of breast lymphoedema patients it identified changes to the normal drainage pathway of the breast. Understanding these changes will have implications for clinical management.

Title: Tissue Dielectric Constant Measures in Women With and Without Clinical Trunk Lymphedema Following Breast Cancer Surgery: A 78-Week Longitudinal Study.

Authors: Koehler LA; Mayrovitz HN.

Publication: Physical Therapy, ISSN: 1538-6724, 2020

Abstract

Objective: Following breast cancer surgery with lymph node removal, women are at risk of developing lymphedema in the upper extremity or trunk. Currently, trunk lymphedema diagnosis relies on a clinical assessment because no quantifiable standard method exists. Tissue dielectric constant (TDC) values are quantifiable measures of localized skin tissue water and may be able to detect trunk lymphedema. The goal of this study was to (1) compare parameters derived from TDC measurements with those derived from clinically accepted criteria for trunk lymphedema in women following breast cancer surgery and (2) explore the potential utility of TDC to detect trunk lymphedema early in its progression.

Methods: This prospective longitudinal study, a secondary analysis from a larger study, observed women with and without clinically determined truncal lymphedema following breast cancer surgery. TDC was measured on the lateral trunk wall at post-surgery weeks 2, 4, 12, and 78 in women who had surgical breast cancer treatment with lymph node removal. Clinical assessment for trunk lymphedema was determined at 78 weeks by a lymphedema expert. Comparison of TDC measurements in women with and without clinical trunk lymphedema was analyzed.

Results: Clinical assessment identified trunk lymphedema in 15 out of 32 women at 78 weeks. These women had TDC ratios statistically higher than women without truncal lymphedema.

Conclusion: The overall findings indicate that TDC has the ability to quantify trunk lymphedema and might be valuable in early detection.

Impact: TDC may be a beneficial tool in the early detection of breast cancer-related trunk lymphedema, which could trigger intervention.

Lay Summary: A new device may help recognize trunk lymphedema in patients with breast cancer so they could receive appropriate treatment.

Title: Tissue Dielectric Constant Ratios as a Method to Characterize Truncal Lymphedema.

Authors: Mayrovitz HN and Weingrad DN.

Publication: Lymphology 2018 Vol 51: 125-131.

Abstract

Truncal lymphedema is one possible complication of breast cancer treatment. It affects many women and is diagnosed based on symptoms and clinical assessment. Because changes occur late in the process, it is useful to have a quantitative assessment that is applied earlier to detect more subtle changes and quantitively assess treatment progress. Our goal was to describe a possible method to accomplish this via measurements of tissue dielectric constant (TDC). TDC was measured at lateral thorax, anterior forearm, and biceps in 120 women awaiting surgery for breast cancer. Inter-side TDC ratios were defined as values measured on the at-risk (cancer-side) lateral thorax divided by TDC values measured on contralateral thorax, forearm, and biceps. These ratios, designated as thorax-thorax, thorax-forearm, and thorax- biceps were (mean ± SD) 1.017 ± 0.121, 1.138 ± 0.223, and 1.263 ± 0.255 respectively. Corresponding truncal lymphedema thresholds were determined by adding 2.5SD to each mean yielding thresholds of 1.32, 1.70 and 1.90. For these thresholds, 99.4% of patients would have inter-side ratios less than the threshold value. Thus, from assessments in a non-lymphedematous patient-group a set of reference threshold-ratios are now available against which patients surgically treated for breast cancer may be prospectively compared.

Full article available

Title: Breast Oedema Following Free Flap Breast Reconstruction.

Authors: Greenhowe J, Stephen C, McClymont L, Munnoch DA.

Publication: The Breast 2017 Vol 34 p73-76.

Abstract

Objectives: Breast oedema causes significant morbidity and is historically difficult to quantify. The aim of this study was to identify changes in breast tissue water content from pre-operative levels in the native breast to post-operative levels in mastectomy skin flaps and free flaps in the reconstructed breast.

Materials and methods: One hundred patients undergoing unilateral mastectomy and immediate free flap breast reconstruction were examined pre-operatively and at three post-operative appointments. A validated moisture meter was used to record dermal water percentages of each breast quadrant and areola in both breasts pre-operatively, then four quadrants of both breasts plus the unaffected areola and free flap at each post-operative review.

Results and conclusion: Native skin of the reconstructed breast showed significant, persistent increase in MWC from 45.6% ± 0.5% to 72.8% ± 0.9% at 1st follow up (p < 0.001), decreasing only to 67.6% ± 0.8% by 3rd follow up. There was a marked difference (p < 0.001) in the mean water content (MWC) of the initial free flap (39.7% ± 0.6%) compared to 61.8% ± 1.7% at 1st follow up, then 55.1% ± 1.4% at 2nd and 53.7% ± 1.3% at 3rd follow ups. The unaffected breast showed a small but significant increase in MWC of all quadrants at subsequent follow up (greatest difference 3.1% at 1st follow up). This patient group demonstrates significant, persistent oedema of the reconstructed breast, which can be monitored using a non-invasive moisture meter. [/av_toggle] [/av_toggle_container] [av_hr class='default' height='50' shadow='no-shadow' position='center' custom_border='av-border-thin' custom_width='50px' custom_border_color='' custom_margin_top='30px' custom_margin_bottom='30px' icon_select='yes' custom_icon_color='' icon='ue808' av-desktop-hide='' av-medium-hide='' av-small-hide='' av-mini-hide=''] [av_textblock size='' font_color='' color='' av-medium-font-size='' av-small-font-size='' av-mini-font-size='' admin_preview_bg=''] Title: Two-Year Follow-Up of Temporal Changes of Breast Edema After Breast Cancer Treatment With Surgery And Radiation Evaluated By Tissue Dielectric Constant.

Authors: Johansson K, Lahtinen T, Bjork-Eriksson T, Darkeh SE.

Publication: 2015 European Journal of Lymphology and Related Problems 27(73):15-21.
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Abstract


Background: Breast edema is reported as a common complaint after breast conserving surgery and radiotherapy (RT). Measurements of local water in skin and upper subcutis with tissue dielectric constant (TDC) technique have the potential to detect breast edema in patients after breast cancer treatment.

Objective: The purpose of the present study was to examine development of edema in breast, axilla and upper arm in women treated with breast conserving surgery and RT during a 2-year follow-up.

Method: Sixty-five patients have been included and measured at 10 time-points (before RT, three time-points during RT, 2 and 4 weeks after RT and then 3, 6, 12 and 24 months after RT). Breast edema was measured by tissue water content in skin and upper subcutis at both sides with MoistureMeterD. TDC, directly proportional to tissue water content to the effective depth of 2.5 mm, was evaluated. Definition of breast edema was determined as a TDC ratio ≥ 1.40 between the treated and healthy breast.

Results: The TDC measurements demonstrated breast edema already before RT. The mean TDC ratios at three weeks of RT and at 3- and 6-months post-RT were exceeding the edema threshold limit (i.e. TDC ratio ≥1.40). The largest proportions of patients exceeding the edema threshold limit were found at three- and six-month post-RT (63%) and the smallest proportions at two years post-RT (28%). Concerning axillary dissection or sentinel node biopsy, no statistically significant differences were found between the groups at any of the 10 different measurement time-points.

Conclusion: Cancer treatment related edema in the breast is very frequent at three to six months after RT but decreases at one to two years after RT. Differences in the surgical procedure are unlikely to change the incidence of breast edema during a two-year follow-up period.

Full article available

Title: Breast Oedema Following Breast Conserving Surgery and Radiotherapy.

Authors: Johansson, K, Lahtinen T and Bjork-Eriksson T.

Publication: 2014 European Journal of Lymphology and Related Problems 25(70):1-5.

Abstract

Introduction: Breast edema following cancer treatment is very rarely documented. The aim of this study was to investigate tissue water content in skin and upper subcutis in women treated for breast cancer with breast conserving surgery and radiotherapy (RT) to the breast and compare the changes with the healthy breast.

Material and methods: One hundred eighteen patients were measured prior to, during and 2 and 4 weeks after end of RT. Local edema in the four quadrants of both breasts was measured with MoistereMeterD (Delfin Technologies Ltd, Finland). A parameter, tissue dielectric constant (TDC), directly proportional to tissue water content to the effective depth of 2.5 mm, was calculated. Breast edema was defined as a TDC ratio exceeding 1.40 (mean + 2S0) between the irradiated and healthy breast.

Results: Difference in TDC ratio (p <0.001) between the operated and healthy breast was found at each measurement time-point. The incidence of breast edema was 31.4% before start of the RT treatment, increasing during RT and was 62.6% at 4 weeks after completion of RT. The mean pre-RT TDC ratio 1.30 ± 0.29 increased during the first week of therapy to 1.43 ± 0.33 and stayed elevated through the observation period (p <0.001). Pre-RT patients with scar in quadrant 4 showed higher TDC ratio (p 0.02) (n = 71, ThC ratio 1.36 ± 0.31) than patients with no scar tissue in quadrant 4 (n = 46, a TDC ratio 1.20 ± 0.23). Conclusion: The healthy breast can act as a control to provide a ratio between the breasts. Based on the evaluation of the mean TDC ratio, the incidence of breast edema was found to be high (>30%). The TDC values illustrating edema in the operated breast were higher compared to the healthy breast at all measurement time-points, also pre-RT, suggesting a high influence of surgery on breast edema, However, axillary surgery did not seem to increase breast edema more than sentinel lymph node biopsy. It was also shown that patients with scar in the fourth quadrant are more likely to have a higher TDC ratio. The higher weekly doses in the hypofractionated RT seem to induce more edema than conventional fractionation

Full article available

Lower limb

Title: Possible Applications of Normative Lower to Upper Limb Ratios Of Tissue Dielectric Constant To Lower Extremity Edema.

Authors: Mayrovitz HN, Alvarex A, Labra M, Mikulka A, Woody D.

Publication: International Angiology 2019 Vol 38 (1) p70-75.

Abstract

Background Lower extremity edema occurs in many conditions including congestive heart failure, lymphedema, diabetes-related, kidney and liver disease, chronic venous insufficiency with venous hypertension. Clinical edema assessment methods are often subjective and variable. Our goals were to introduce a simple noninvasive measurement procedure potentially useful to characterize lower extremity edema by providing normative values from which edema thresholds might emerge.

Methods Tissue dielectric constant (TDC) values, as indices of skin-to-fat tissue water, were measured on foot dorsum, lower medial leg and anterior forearm of 88 adults (44 female) with ages ranging from 19-77 years with BMI ranging from 18.3-40.6 kg/m2. From these direct measurements lower-to-upper extremity TDC ratios (foot/arm and leg/arm) were determined for each gender. Possible edema threshold ratios were calculated as the mean lower-to-upper ratio to which was added two standard deviations of the overall ratio thereby providing initial thresholds for future testing.

Results Results showed that at each anatomical site absolute TDC values for males significantly exceed those of females (P<0.001). Male vs. female TDC values were 33.0±5.4 vs. 27.7±4.0 for the forearm, 34.8±6.5 vs. 27.5±4.6 for the leg, and 32.5±6.5 vs. 28.7±5.1 for the foot. In contrast, the foot/arm and leg/arm ratios were similar between genders ranging 0.990±0.144 to 1.063±0.170. Corresponding lower extremity to upper extremity threshold ratios ranged from 1.278 for foot/arm to 1.403 for leg/arm. The composite ratios considering both gender ration (N.=88) yielded a composite threshold foot/arm ratio of 1.387 and a leg/arm threshold ratio of 1.324.

Conclusions This assessment method together with the normative ratios and calculated thresholds may aid in rapid detection of lower extremity edema in patients and possibly as a way to quantitatively track changes in edema status with time or treatment. However, the suitability of these thresholds is subject to future validation in persons with clearly defined lower extremity edema for which this report’s findings serve as an initial quantitative starting point.

Full article available

Title: Assessing Lower Extremity Lymphedema Using Upper and Lower Tissue Dielectric Constant Ratios: Method and Normal Reference Values.

Authors: Mayrovitz, HN.

Publication: Lymphatic Research and Biology 2019 Vol 17(4) p316-321.

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Abstract

Background: Lower extremity swelling accompanies many conditions, including gynecological surgery and chronic venous dysfunction. Some clinical and quantitative assessment methods exist, but other ways to rapidly assess early lymphedema and track changes are needed. Our goal was to use lower to upper extremity intraside tissue dielectric constant (TDC) ratios with the specific aim of providing normal reference values potentially useful as a comparison measure against which persons at risk for lower extremity lymphedema might be evaluated.

Methods and Results: TDC ratios (calf/forearm, foot/forearm) were measured in 44 young (25.1 ± 2.2 years) and 60 mature (60.1 ± 11.5 years) volunteers equally divided by gender. Foot/forearm and calf/forearm ratios did not differ between genders. For mature, values measured on dominant sides were 1.050 ± 0.151 and 1.013 ± 0.162, respectively. Lymphedema threshold ratios, calculated as the mean ratio plus twice their respective standard deviations, were for calf/forearm and foot/forearm 1.352 and 1.337, respectively. As an initial test of the thresholds, they were compared to TDC ratios determined in six patients with lower extremity edema due to congestive heart failure.

Conclusion: Based on these findings, it is proposed that a calf/forearm TDC ratio that exceeds 1.35 is suggestive of lower extremity lymphedema and that the calf/forearm ratio could be used to track temporal changes and therapy-related improvements. The test of these conclusions requires future research in which these intraside TDC ratios and thresholds are evaluated in patients with lower extremity lymphedema and venous-related edema. This work provides the reference values for such comparisons to be systematically done.

Full article available

Title: Tissue Dielectric Constant and Circumference Measurement in the Follow-Up of Treatment-Related Changes in Lower-Limb Lymphedema.

Authors: Tugral, Viren, Bakar.

Publication: International Angiology 2018 Vol 37(1) p26-31.

Abstract

Background: Lymphedema of lower limbs is a chronic condition that requires life-long management. Therapeutic effect of complex decongestive physiotherapy (CDP) is most often followed by circumference measurements (CM). However, the CM measurements are not specific to interstitial tissue fluid and have problems in sensitivity and objectivity. The aim of present study was to evaluate the therapeutic effect of CDP with a new tissue water specific measurement technique, in patients with lower limb lymphedema (LLL).

Methods: A total of 17 patients with unilateral LLL (11 primary, 6 secondary lymphedema) were recruited in this study. CDP was applied for 5 days a week for 4 weeks. CM measurement of both limbs was performed at nine sites along limb by tape measure. Percentage skin water content (PWC) of thigh, calf and ankle was measured in affected lymphedema limb and contralateral limb with MoistureMeterD Compact (MMDC) device. Inter-limb PWC ratio was calculated by dividing affected side’s PWC value with PWC of contralateral limb. Patients were asked to fullfill the Lymph Quality of Life Questionnaire.

Results: Significant reduction of circumference after CDP was detected at all nine measurement sites along lower limb (P<0.01). PWC measurements showed a significant decrease of skin tissue water at thigh, calf and ankle measurement sites after CDP (P<0.001). Inter-limb PWC ratios demonstrated significant reduction of edema between affected and contraletral limbs post-treatment (P<0.003). CDP also increased the quality of life (P=0.006). Conclusions: CM and PWC measurements reflected a positive effect of CDP in patients with LLL. Both absolute PWC values and inter-limb PWC ratios were meaningful tools to follow the effect of therapautic intervention. Compared with CM measurements the TDC technique offered easier, quicker, objective and more practical measurements for routine assessments of LLL.

Full article available

Title: Can Tissue Dielectric Constant Measurement Aid in Differentiating Lymphoedema from Lipoedema in Women With Swollen Legs?

Authors: Birkballe S, Jensen MR, Noerregaard S, Gottrup F, Karlsmark T

Publication: Br J Dermatol. 2014 Vol 170(1) p96-102.

Abstract

Background Distinguishing lymphoedema from lipoedema in women with swollen legs can be difficult. Local tissue water content can be quantified using tissue dielectric constant (TDC) measurements.

Objectives To examine whether TDC measurements can differentiate untreated lower extremity lymphoedema from lipoedema, and to test interobserver agreement.

Methods Thirty-nine women participated in the study; 10 patients with lipoedema (LipP), nine patients with untreated lymphoedema (U-LP), 10 patients with lymphoedema treated with compression bandaging for ≥ 4 weeks (T-LP) and 10 healthy controls. All subjects were measured at three predefined sites (foot, ankle and lower leg). All groups except U-LP were measured by three blinded investigators. Using a handheld device, a 300-MHz electromagnetic wave is transmitted into the skin via a 2·5-mm depth probe. TDC calculated from the reflected wave is directly proportional to tissue water content ranging from 1 (vacuum) to 78·5 (pure water).

Results Mean ± SD TDC values for U-LP were 48·8 ± 5·2. TDC values of T-LP, LipP and controls were 34·0 ± 6·6, 29·5 ± 6·2 and 32·3 ± 5·7, respectively. U-LP had significantly higher TDC values in all measurement sites compared with all other groups (P < 0·001). A cut-off value of 40 for ankle and lower-leg measurements correctly differentiated all U-LP from LipP and controls. Intraclass correlation coefficients were 0·94 for the ankle and the lower leg and 0·63 for the foot. Conclusions TDC values of U-LP were significantly higher than those of T-LP, LipP and controls and may aid in differentiating lymphoedema from lipoedema. Interobserver agreement was high in ankle and lower-leg measurements but low in foot measurements.

Title: Validity and Interobserver Agreement of Lower Extremity Local Tissue Water Measurements in Healthy Women Using Tissue Dielectric Constant.

Authors: Jensen MR, Birkballe S, Nørregaard S, Karlsmark T.

Publication: Clinical Physiology & Functional Imaging 2012 Vol 32 (4) p317.

Abstract

Background: Tissue dielectric constant (TDC) measurement may become an important tool in the clinical evaluation of chronic lower extremity swelling in women; however, several factors are known to influence TDC measurements, and comparative data on healthy lower extremities are few.

Methods: Thirty-four healthy women volunteered. Age, BMI, moisturizer use and hair removal were registered. Three blinded investigators performed TDC measurements in a randomized sequence on clearly marked locations on the foot, the ankle and the lower leg. The effective measuring depth was 2.5 mm.

Results: The mean TDC was 37.8 ± 5.5 (mean ± SD) on the foot, 29.0 ± 3.1 on the ankle and 30.5 ± 3.9 on the lower leg. TDC was highly dependent on measuring site (P<0.001) but did not vary significantly between investigators (P=0.127). Neither age, BMI, hair removal nor moisturizer use had any significant effect on the lower leg TDC. Intraclass correlation coefficients were 0.77 for the foot, 0.94 for the ankle and 0.94 for the lower leg. Conclusion: The TDC on the foot was significantly higher compared with ankle and lower leg values. Foot measurements should be interpreted cautiously because of questionable interobserver agreement. The interobserver agreement was high on lower leg and ankle measurements. Neither age, BMI, hair removal nor moisturizer use had any significant on effect on the lower leg TDC. TDC values of 35.2 for the ankle and 38.3 for the lower leg are suggested as upper normal reference limits in women.

Upper Limb

Title: Tissue Dielectric Constant Measures in Women With and Without Clinical Trunk Lymphedema Following Breast Cancer Surgery: A 78-Week Longitudinal Study

Authors: Koehler LA; Mayrovitz HN.

Publication: Physical Therapy 2020 Vol 100(8) p1384-1392.

Abstract

Objective: Following breast cancer surgery with lymph node removal, women are at risk of developing lymphedema in the upper extremity or trunk. Currently, trunk lymphedema diagnosis relies on a clinical assessment because no quantifiable standard method exists. Tissue dielectric constant (TDC) values are quantifiable measures of localized skin tissue water and may be able to detect trunk lymphedema. The goal of this study was to (1) compare parameters derived from TDC measurements with those derived from clinically accepted criteria for trunk lymphedema in women following breast cancer surgery and (2) explore the potential utility of TDC to detect trunk lymphedema early in its progression.

Methods: This prospective longitudinal study, a secondary analysis from a larger study, observed women with and without clinically determined truncal lymphedema following breast cancer surgery. TDC was measured on the lateral trunk wall at post-surgery weeks 2, 4, 12, and 78 in women who had surgical breast cancer treatment with lymph node removal. Clinical assessment for trunk lymphedema was determined at 78 weeks by a lymphedema expert. Comparison of TDC measurements in women with and without clinical trunk lymphedema was analyzed.

Results: Clinical assessment identified trunk lymphedema in 15 out of 32 women at 78 weeks. These women had TDC ratios statistically higher than women without truncal lymphedema.

Conclusion: The overall findings indicate that TDC has the ability to quantify trunk lymphedema and might be valuable in early detection. Impact: TDC may be a beneficial tool in the early detection of breast cancer related trunk lymphedema which could trigger intervention.

Full article available

Title: Reliability of the MoistureMeterD Compact Device and the Pitting Test to Evaluate Local Tissue Water in Subjects with Breast Cancer-Related Lymphedema.

Authors: De Vrieze T, Gebruers N, Nevelsteen I, De Groef A, Tjalma W, Thomis S, Dams L, Van der Gucht E, Penen F, Devoogdt N.

Publication: Lymphatic Research Biology 2020 Vol 18 (2) p116-128.

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Abstract

Background: Local tissue water in patients with breast cancer-related lymphedema (BCRL) can be assessed by measurement of the tissue dielectric constant using the MoistureMeterD Compact® (MMDC) device, or by performing the pitting test. Although these assessment methods are commonly used in clinical practice, literature shows a lack of research on their clinimetric properties. Therefore, the aim of this study was to investigate reliability of both methods, in assessing the upper limb in BCRL.

Methods and Results: Thirty women with BCRL were enrolled. Local tissue water was evaluated at nine reference points on the upper limb and trunk, using both methods. To determine intra- and inter-rater reliability of the MMDC device (using the absolute percentages of water content [PWC%] and interarm PWC% ratios based on single and multiple measures), intraclass correlation coefficients (ICCs), and standard errors of the measurement were calculated. To determine intra- and inter-rater agreement of the pitting test, Cohen’s kappa coefficients were calculated as well as percentages of agreement. MMDC measurements yielded moderate to very strong intra- (ICC 0.648-0.947) and inter-rater (ICC 0.606-0.941) reliability, depending on the measurement location on the edematous limb. The pitting test showed a very strong intrarater agreement at nearly all defined points, but a weak inter-rater agreement, especially at the medial elbow and the breast.

Conclusion: This study supports the MMDC device and pitting test as being useful tools in the clinical evaluation of BCRL. However, further research into the concurrent validity of both tools is warranted.

Title: Palpation of Increased Skin and Subcutaneous Thickness, Tissue Dielectric Constant, and Water Displacement Method for Diagnosis of Early Mild Arm Lymphedema.

Authors: Karlsson K, Nilsson-Wikmar L, Brogardh C, Johansson K.

Publication: Lymphatic Research Biology 2020 Vol 18(3) p219-225

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Abstract

Background: Early diagnosis of mild lymphedema and treatment are important to prevent its progress. The tissue dielectric constant (TDC), measuring local tissue water in the skin and upper subcutis, has neither been related to the water displacement method (WDM) nor been used to diagnose mild arm lymphedema in patients at risk. Our aims were to evaluate TDC and WDM in combination with palpation, examine the association between TDC and WDM measurements, and compare lymphedema-related factors.

Methods and Results: Seventy-two women treated for breast cancer were diagnosed with mild arm lymphedema using skin palpation in combination with TDC from fixed measurement sites (threshold ratio for upper arm ≥1.45 and forearm ≥1.3) and/or WDM (lymphedema relative volume [LRV]: ≥5% to ≤8%). Results revealed that 32 (45%) women were diagnosed by TDC only, 19 (26%) by WDM only, and 21 (29%) by both TDC and WDM. TDC ratios exceeding the threshold were most frequently identified on the medial site of the arm, proximal and distal to the antecubital fossa. TDC and WDM were negatively associated; LRV (r = −0.545, p < 0.001). The women diagnosed by TDC only were diagnosed earlier after surgery (p = 0.003) and had a lower LRV (1.3%) than those diagnosed by WDM only (6.3%) or both TDC and WDM (6.2%; p < 0.001). Conclusions: TDC and WDM can be used together for early diagnosis of arm lymphedema, but TDC is the most valid method, determining the diagnosis earlier after surgery and at a lower arm volume than WDM.

Full article available

Title: Factors Affecting Interpreting of Tissue Dielectric Constant (TDC) in Assessing Breast Cancer Treatment Related Lymphedema (BCRL).

Authors: Mayrovitz HN, Arzanova E, Somarriba S, Eisa S.

Publication: Lymphology 2019 Vol 52 p92-102.

Abstract

Tissue dielectric constant (TDC) measurements are increasingly used as quantitative adjunctive tools to detect and assess lymphedema. Various factors affect measured TDC values that may impact clinical interpretations. Our goal was to investigate possible impacts of: 1) anterior vs. medial arm measures, 2) total body water (TBW%) and arm fat percentages (AF%), 3) measurement depth, and 4) skin firmness. In 40 healthy women (24.5±2.5 years), TDC was measured bilaterally on anterior forearm to 0.5, 1.5, 2.5, and 5.0 mm depths using a multiprobe device and on anterior and medial aspects using a compact device. TBW% and AF% were measured at 50KHz and skin firmness measured by skin indentation force (SIF). Results showed: 1) No statistically significant difference in TDC values between anterior and medial arm, 2) a moderate direct correlation between TDC and TBW% (r=0.512, p=0.001), 3) an inverse correlation between TDC and AF% (r= -0.494, p<0.001) with correlations greatest at the deepest depth, and 4) a slight but statistically significant inverse correlation between TDC and SIF (r= -0.354, p=0.001). TDC values with compact vs. multiprobe were within 6% of each other with interarm (dominant/nondominant) ratios not significantly different. The findings provide a framework to help interpret TDC values among divergent conditions. [/av_toggle] [/av_toggle_container] [av_promobox button='yes' label='View PDF' link='manually,https://lymphoedemaeducation.com.au/wp-content/uploads/2021/07/12-Factors-affecting-Interpreting-of-Tissue-Dielectric-Constant.pdf' link_target='_blank' color='theme-color' custom_bg='#444444' custom_font='#ffffff' size='large' icon_select='no' icon='ue800' font='entypo-fontello' box_color='' box_custom_font='#ffffff' box_custom_bg='#444444' box_custom_border='#333333' admin_preview_bg=''] Full article available [/av_promobox] [av_hr class='default' height='50' shadow='no-shadow' position='center' custom_border='av-border-thin' custom_width='50px' custom_border_color='' custom_margin_top='30px' custom_margin_bottom='30px' icon_select='yes' custom_icon_color='' icon='ue808' av-desktop-hide='' av-medium-hide='' av-small-hide='' av-mini-hide=''] [av_textblock size='' font_color='' color='' av-medium-font-size='' av-small-font-size='' av-mini-font-size='' admin_preview_bg=''] Title: Impact of Body Fat and Obesity on Tissue Dielectric Constant (TDC) as a Method to Assess Breast Cancer Treatment Related Lymphedema (BCRL).

Authors: Mayrovitz H.

Publication: Lymphology 2019 Vol 52 p18-24.
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Abstract


Obesity is linked to the risk of breast cancer and treatment-related lymphedema (BCRL). Thus, knowledge of how obesity, or more specifically total body fat percentage (TBF) and body mass index (BMI), affect measurements that are used to detect or track lymphedema is clinically important. Tissue dielectric constant (TDC) is one measure used to help characterize lymphedema features, detect its presence, and assess treatment-related changes. The goal of this research was to determine the extent to which TDC values depend on TBF and BMI. TDC was measured on both forearms (2.5mm depth) in 250 women (18-72 years) along with TBF (impedance, 50KHz). TBF was 12.2%- 54.4% (median=29.3%) and BMI was 14.7Kg/m2-44.3 Kg/m2 (median=22.6 Kg/m2). TDC values and interarm ratios were compared between subgroups that had TBF and BMI values in lower vs. upper quartiles. Subjects in the upper quartile had slightly lower TDC values (1.3 TDC units, p <0.01) that was at most a 5% differential. Contrastingly, TDC interarm ratios were not dependent on TBF or BMI levels. These findings suggest that when tracking lymphedema changes using the TDC method, treatment-related or temporal changes in a woman's TBF or BMI are unlikely to significantly impact TDC values or their interarm ratios. [/av_toggle] [/av_toggle_container] [av_promobox button='yes' label='View PDF' link='manually,https://lymphoedemaeducation.com.au/wp-content/uploads/2021/07/13-Impact-of-Body-Fat-and-Obesity-on-Tissue-Dielectric-Constant.pdf' link_target='_blank' color='theme-color' custom_bg='#444444' custom_font='#ffffff' size='large' icon_select='no' icon='ue800' font='entypo-fontello' box_color='' box_custom_font='#ffffff' box_custom_bg='#444444' box_custom_border='#333333' admin_preview_bg=''] Full article available [/av_promobox] [av_hr class='default' height='50' shadow='no-shadow' position='center' custom_border='av-border-thin' custom_width='50px' custom_border_color='' custom_margin_top='30px' custom_margin_bottom='30px' icon_select='yes' custom_icon_color='' icon='ue808' av-desktop-hide='' av-medium-hide='' av-small-hide='' av-mini-hide=''] [av_textblock size='' font_color='' color='' av-medium-font-size='' av-small-font-size='' av-mini-font-size='' admin_preview_bg=''] Title: Reference Values for Assessing Localized Hand Lymphedema Using Inter-Hand Tissue Dielectric Constant Ratios

Authors: Mayrovitz HN, Arzanova E, Somarriba S, Eisa S.

Publication: Lymphatic Research and Biology 2018 16(5) Vol 16(5) p442-444
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Abstract


Background: Early detection and tracking of breast cancer treatment-related lymphedema have been helped by quantitative assessment methods and parameters, including bioelectrical impedance spectroscopy and tissue dielectric constant (TDC). Such measurements are evaluated with respect to interarm differences or ratios that (when exceeding specified thresholds) are suggestive of lymphedema. Specific threshold ratios depend on the assessment method and have been reported for arms. However, there is far less information available on thresholds to assess lymphedema that manifests in at-risk hands and essentially nothing known about TDC ratios in healthy hands. Such information is essential to establish reference values from which lymphedema threshold TDC values may be estimated. The specific aim of this research was to determine such interhand TDC ratios applicable to both young and mature women.

Methods and results: A total of 70 women (35 under 30 years of age, YOUNG, and 35 over 50 years of age, MATURE) participated after signing an approved institutional review board informed consent. TDC values of the hand dorsum web were measured bilaterally in triplicate with participants in a supine resting position. Results showed MATURE TDC values to be about 15% less than YOUNG (p < 0.01) on dominant and nondominant hands, but no statistical difference in dominant/nondominant interarm ratios (1.026 ± 0.100). Conclusions: Based on this data set’s overall mean and two standard deviation value, an age-independent interhand TDC threshold ratio of 1.23 emerges as potentially useful for lymphedema detection. This is a good initial start threshold that is usable in future clinical and research assessments.

Title: Role of Handedness on Forearm Skin Tissue Dielectric Constant (TDC) in Relation to Detection of Early-Stage Breast Cancer-Related Lymphedema.

Authors: Mayrovitz HN, Fasen M, Spagna P, Wong J.

Publication: Clinical Physiology and Functional Imaging 2018 Vol 38, p670-675.

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Abstract

Skin tissue dielectric constant (TDC) measurements help assess local skin water to detect incipient early-stage lymphedema subsequent to breast cancer treatment-related lymphedema. However, presurgery measurements are not always obtained and assessments for evolving lymphedema are only made after surgery. Thus, subsequent TDC assessments may be biased in an unknown way dependent on a patient’s handedness in relation to the at-risk arm. We investigated this issue by comparing TDC values in dominant and non-dominant volar forearms of 31 left-handed women and 31 right-handed women (age range 24–84 years). Body fat and water percentages were assessed by bioimpedance at 50 KHz. Results showed that TDC values of dominant versus non-dominant arms did not significantly differ for left-handers or for right-handers. There was also no statistically significant difference in absolute TDC values between left- and right-handers or a statistically significant difference in dominant-to-non-dominant arm ratios between left- and right-handers. For the composite data set (N = 62), TDC values for dominant and non-dominant arms were, respectively, 30·0 ± 4·6 and 29·6 ± 4·2 and the dominant-to-non-dominant arm TDC ratio for combined left- and right-handers was 1·015 ± 0·075. These results suggest that handedness is not a major factor when assessing lymphedema status in women who have previously been treated for breast cancer but for whom pretreatment TDCvalues have not been obtained. Moreover, these results suggest that threshold ratios of incipient subclinical unilateral lymphedema based on interarm TDC ratios apply independent of a patient’s handedness for the site and tissue depths herein measured.

Full article available

Title: Skin Indentation Firmness and Tissue Dielectric Constant Assessed in Face, Neck, and Arm Skin of Young Healthy Women.

Authors: Mayrovitz HN, Corbitt K, Grammenos A, Abello A, Mammino J.

Publication: Skin research and technology: official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI) [Skin Res Technol], ISSN: 1600-0846, 2017 Feb; Vol. 23 (1) p 112-120.

Abstract

Purpose: Our goal was to test the hypothesis that skin firmness correlates with skin hydration.

Methods: Dermal water was assessed by tissue dielectric constant (TDC) at 0.5 mm (TDC0.5 ) and 2.5 mm (TDC2.5 ) depths on four face sites and two arm sites of 35 women (25.0 ± 1.6 years). Firmness was determined by force (mN) to indent skin to 0.3 mm (F0.3 ) and 1.3 mm (F1.3 ).

Results: F0.3 was similar among face sites (avg = 16.2 ± 7.2 mN) but F1.3 varied (avg = 32.5 ± 4.1 mN). TDC2.5 was similar among face sites (avg = 37.7 ± 4.2) but TDC0.5 varied (avg = 36.2 ± 4.8). F1.3 of arm sites was similar (avg = 60.2 ± 18.6 mN) and both greater than F1.3 of neck (28.3 ± 7.1 mN) and face. Regression analysis showed a near-zero correlation between forces and TDC at all sites.

Conclusion: The near-zero correlation may be due to low skin interstitial hydraulic resistance to mobile water movement in healthy young skin. If true, then conditions in which dermal hydraulic conductance is reduced as in lymphedematous, diabetic, or aged skin are more likely show the hypothesized relationship. Our findings provide normalized reference values and suggest that such persons are an important population to study to test for a possible skin water-indentation force relationship and its utilization for early diagnosis.

Title: Age-Related Differences in Tissue Dielectric Constant Values of Female Forearm Skin Measured Noninvasively At 300 Mhz.

Authors: Mayrovitz HN, Singh A, Akolkar S.

Publication: Skin research and technology: official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI) [Skin Res Technol], ISSN: 1600-0846, 2016 May; Vol. 22 (2) p 189-95.

Abstract

Background/purpose: We hypothesized that reported age-related shifts in skin water from less-to-more mobile states would result in increased skin tissue dielectric constant (TDC) values as TDC values depend strongly on water content and state. One aim was to test this hypothesis. Further, as skin-to-fat TDC values are used as a tool for edema and lymphedema assessment, a second aim was to establish reference values suitable for young and older women.

Methods: TDC was measured bilaterally on volar forearm skin in young (20-40 years) and older (≥60 years) women. There were four groups with 50, 50, 100, and 50 subjects per age group measured to depths of 0.5, 1.5, 2.5, and 5.0 mm, respectively.

Results: For each age group, TDC values decreased with increasing depth (P < 0.001). TDC values at 0.5 and 1.5 mm were greater for older women (P < 0.001). At 2.5 mm, there was no age-group difference (P = 0.108). At 5.0 mm the direction of the difference reversed with older TDC values less than the younger (P < 0.001). Conclusion: Results are consistent with age-related shifts in water state from less-to-more mobile and explain depth-dependence differences between age groups. Data also give age-related TDC reference values for assessing local edematous or lymphedematous states.

Full article available

Title: Assessing Localized Skin-to-Fat Water in Arms of Women with Breast Cancer via Tissue Dielectric Constant Measurements in Pre-Surgery Patients.

Authors: Mayrovitz HN, Weingrad DN, Lopez L.

Publication: Ann Surg Oncol. 2015 May;22(5) p1483-9.

Abstract

Background: Skin-to-fat tissue dielectric constant (TDC) values at 300 MHz largely depend on tissue water and provide a rapid way to assess skin water by touching skin with a probe for approximately 10 s. This method has been used to investigate lymphedema features accompanying breast cancer (BC), but relationships between TDC and nodes removed, or symptoms is unclear. Our goals were: (1) to compare TDC values in BC patients prior to surgery (group A) and in patients who had BC-related surgery (group B) to determine if TDC of group B were related to nodes removed and reported symptoms and (2) to develop tentative lymphedema-detection thresholds.

Methods: Arm volumes and TDC values of at-risk and contralateral forearms and biceps were determined in 103 women awaiting surgery for BC and 104 women who had BC-related surgery 26.3 ± 17.5 months prior to evaluation. Inter-arm ratios (at-risk/contralateral) were determined and patients answered questions about lymphedema-related symptoms.

Results: Inter-arm TDC ratios for group A forearm and biceps were respectively 1.003 ± 0.096 and 1.012 ± 0.143. Group B forearm ratios were significantly greater, and among group B patients who reported at least one symptom there was a significant correlation between TDC ratios and symptom burden and nodes removed.

Conclusions: Inter-arm TDC ratios are significantly related to symptoms and nodes removed. Ratios increase with increasing symptom score and might be used to detect pre-clinical unilateral lymphedema using TDC ratio thresholds of 1.30 for forearm and 1.45 for biceps. Threshold confirmation awaits targeted prospective studies but can serve as guideposts to provide quantitative and easily done tracking assessments during follow-up visits.

Full article available

Title: Patterns of Temporal Changes in Tissue Dielectric Constant as Indices of Localized Skin Water Changes in Women Treated for Breast Cancer: A Pilot Study.

Authors: Mayrovitz HN, Weingrad DN, Lopez L.

Publication: Lymphatic Research and Biology 2015 Volume 13(1) p20-32.

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Abstract

Background: Our goal was to characterize temporal patterns of skin Tissue Dielectric Constant (TDC) as a foundation for possible TDC use to detect and quantify lymphedema. Although limb volumes and bioimpedance analysis (BIA) are used for this purpose, potential TDC-method advantages are that it can be done in about 10 seconds at any body site to depths from 0.5 to 5.0 mm below the epidermis.

Methods and results: TDC at forearm, biceps, axilla, and lateral thorax, and BIA values and arm volumes were measured in 80 women with breast cancer prior to surgery and in decreasing numbers at 3, 6-, 12-, 18-, and 24-months post-surgery. Results show that TDC values, reflecting water content in the measurement volume, vary by site and depth but that at-risk/contralateral side ratio (A/C) is relatively independent of site and depth and is the preferred TDC parameter to detect tissue water changes over time in unilateral conditions. Among sites measured, lateral thorax, followed by forearm, appears most useful for TDC measurements with axilla least useful. Pre-surgery TDC inter-side values and A/C ratios showed no significant inter-side differences, suggesting that breast cancer presence per se did not alter tissue water status in this patient population. Sequential changes in TDC A/C ratios detected a greater number of patients who had inter-arm ratio increases exceeding 10% than were detected using BIA ratios. This may indicate a greater sensitivity to localized tissue water changes with the TDC-method.

Conclusions: TDC is a technically viable and potentially useful method to track skin water changes in persons treated for breast cancer.

Title: Experimental and Analytical Comparisons of Tissue Dielectric Constant (TDC) and Bioimpedance Spectroscopy (BIS) in Assessment of Early Arm Lymphedema in Breast Cancer Patients after Axillary Surgery and Radiotherapy.

Authors: Lahtinen T, Seppala J, Tuomas Viren T, Johansson K.

Publication: Lymphatic Research and Biology 2015 Volume 13(3) p176-185.

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Abstract

Background: Early diagnosis of breast cancer treatment-related lymphedema (BCRL) is of great importance for longstanding treatment results. Tissue dielectric constant (TDC) and bioimpedance spectroscopy (BIS) both have a potential for early diagnosis but have not been compared.

Methods and results: One hundred women, treated for breast cancer with breast surgery, axillary dissection, and radiotherapy, were examined within one year after breast cancer treatment, as part of the follow-up procedure. Affected/at-risk and contralateral arms were measured with the TDC technique specific to localized skin water content and the BIS technique assessing arm extracellular fluid (ECF). Thirty-eight patients were clinically diagnosed for lymphedema (38.0%). The sensitivity and specificity for the TDC method were 65.8% and 83.9%, and for BIS method 42.1% and 93.5%, (p < 0.001 and NS), respectively. Of all lymphedema, 18.4% were detected only by TDC and 2.6% by BIS. Affected arm to contralateral arm TDC ratios for upper arm and forearm, 1.56 ± 0.49 and 1.28 ± 0.33, demonstrating the localized feature of the TDC measurements were significantly greater than the BIS arm ratio 1.12 ± 0.12 (both p < 0.001). Conclusions: Discrepancies between TDC and BIS techniques in assessing lymphedema are related to different measurement techniques and assessed tissue water components. Independently of selected technique-specific threshold limit, the TDC technique was more sensitive than the BIS technique in the early assessment of BCRL and demonstrated that nearly 20% of early lymphedema are only superficially localized. The results further supported the complementary role of TDC and arm volume measurements as a highly diagnostic method for early lymphedema.

Title: Tissue Dielectric Constant (TDC) Measurements as a Means of Characterizing Localized Tissue Water in Arms of Women With and Without Breast Cancer Treatment Related Lymphedema.

Authors: Mayrovitz HN, Weingrad DN, Davey S.

Publication: Lymphology 2014 Vol 47 p142-150.


Abstract


Quantitative measurements to detect lymphedema early in persons at-risk for breast cancer (BC) treatment-related lymphedema (BCRL) can aid clinical evaluations. Since BCRL may be initially manifest in skin and subcutis, the earliest changes might best be detected via local tissue water (LTW)measurements that are specifically sensitive to such changes. Tissue dielectric constant (TDC) measurements, which are sensitive to skin-to-fat tissue water, may be useful for this purpose. TDC differences between lymphedema to us and non-lymphedema to us tissue has not been fully characterized. Thus, we measured TDC values (2.5 mm depth) in forearms of three groups of women (N=80/group): 1) healthy with no BC (NOBC), 2) with BC but prior to surgery, and 3) with unilateral lymphedema (LE). TDC values for all arms except LE affected arms were not significantly different ranging between 24.8 ± 3.3 to 26.8 ±4.9 and were significantly less (p<0.001) as compared to 42.9 ± 8.2 for LE affected arms. Arm TDC ratios, dominant/non-dominant or NOBC, were 1.001 ± 0.050 and at-risk/contralateral for BC were 0.998 ± 0.082 with both significantly less (p<0.001) than LE group affected/control arm ratios (1.663 ±0.321). These results show that BC per se does not significantly change arm LTW and that the presence of BCRL does not significantly change LTW of non-affected arms. Further, based on 3 standard deviations of measured arm ratios, our data demonstrates that an at-risk arm/contralateral arm TDC ratio of 1.2and above could be a possible threshold to detect pre-clinical lymphedema. Further prospective measurement trial are needed to confirm this value. [/av_toggle] [/av_toggle_container] [av_promobox button='yes' label='View PDF' link='manually,https://lymphoedemaeducation.com.au/wp-content/uploads/2021/07/17-characterizing-localized-tissue-water-in-arms-of-women-bcl.pdf' link_target='_blank' color='theme-color' custom_bg='#444444' custom_font='#ffffff' size='large' icon_select='no' icon='ue800' font='entypo-fontello' box_color='' box_custom_font='#ffffff' box_custom_bg='#444444' box_custom_border='#333333' admin_preview_bg=''] Full article available [/av_promobox] [av_hr class='invisible' height='50' shadow='no-shadow' position='center' custom_border='av-border-thin' custom_width='50px' custom_border_color='' custom_margin_top='30px' custom_margin_bottom='30px' icon_select='yes' custom_icon_color='' icon='ue808' font='entypo-fontello' admin_preview_bg=''] [/av_one_full][av_one_full first min_height='' vertical_alignment='' space='' custom_margin='' margin='0px' padding='0px' border='' border_color='' radius='0px' background_color='' src='' background_position='top left' background_repeat='no-repeat' animation='' mobile_breaking='' mobile_display=''] [av_hr class='invisible' height='50' shadow='no-shadow' position='center' custom_border='av-border-thin' custom_width='50px' custom_border_color='' custom_margin_top='30px' custom_margin_bottom='30px' icon_select='yes' custom_icon_color='' icon='ue808' font='entypo-fontello' admin_preview_bg=''] [/av_one_full]