| 1. |
- Aberg, P., et al.
(författare)
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Assessment of skin lesions and skin cancer using simple electrical impedance indices
- 2003
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Ingår i: Skin research and technology. - : Wiley. - 0909-752X .- 1600-0846. ; 9:3, s. 257-261
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Tidskriftsartikel (refereegranskat)abstract
- Background/aims: Purpose of this investigation was to assess benign pigmented cellular nevus (BEN), basal cell carcinoma (BCC), dermatofibroma (DER), dysplastic nevus (DYS), and seborrheic keratoses (SEB) using in vivo noninvasive electrical impedance technique. Methods: Electrical impedance was measured at 258 BEN, 34 BCC, 17 DER, 35 DYS, and 26 SEB lesions. Controls were measured at healthy skin close to the lesions. The impedance was measured between 1 kHz and 1 MHz at five depth settings. After the impedance measurements the lesions were histopathologically diagnosed. The impedance spectra were parameterized to four indices prior to the statistical analysis of the data. Results: There were significant differences between the lesions and their controls for BEN (P<0.001), BCC (P<0.001), DYS (P<0.01), and SEB(P<0.01). Conclusions: There are clear statistical differences between impedance of common lesions and control skin. With some further developments, the impedance technique can be useful as a diagnostic decision support tool for skin cancer assessment.
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| 2. |
- Aberg, P., et al.
(författare)
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Non-invasive and microinvasive electrical impedance spectra of skin cancer - a comparison between two techniques
- 2005
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Ingår i: Skin research and technology. - 0909-752X .- 1600-0846. ; 11:4, s. 281-286
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Tidskriftsartikel (refereegranskat)abstract
- Background/purpose: Bio-electrical impedance spectra of skin cancer and other lesions can be assessed using both regular non-invasive probes and a novel type of microinvasive electrode system with a surface furnished with tiny spikes that penetrate stratum corneum. The aim of the study was to compare the accuracy of detection for various types of skin cancer using impedance spectra measured with these two different electrode systems in an objective way without optimising the power of discrimination. Methods: Impedance spectra of 99 benign nevi, 28 basal cell carcinomas (BCC), and 13 malignant melanomas (MM) were measured using the two electrode systems. Classification of the lesions was made using Fisher's linear discriminant, and the sensitivities and specificities of the techniques were estimated using cross-validation. Results: The best separation between nevi and BCC was achieved using the regular non-invasive probe (96% sensitivity and 86% specificity), whereas the best separation between nevi and MM was achieved using the microinvasive electrodes (92% sensitivity and 80% specificity). Conclusions: Our results indicate that the choice of electrode system is application dependent.
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| 3. |
- Aberg, P., et al.
(författare)
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Skin cancer identification using multifrequency electrical impedance - A potential screening tool
- 2004
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Ingår i: IEEE Transactions on Biomedical Engineering. - 0018-9294 .- 1558-2531. ; 51:12, s. 2097-2102
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Tidskriftsartikel (refereegranskat)abstract
- Electrical bio-impedance can be used to assess skin cancers and other cutaneous lesions. The aim of this study was to distinguish skin cancer from benign nevi using multifrequency impedance spectra. Electrical impedance spectra of about 100 skin cancers and 511 benign nevi were measured. Impedance of reference skin was measured ipsi-laterally to the lesions. The impedance relation between lesion and reference skin was used to distinguish the cancers from the nevi. It was found that it is possible to separate malignant melanoma from benign nevi with 75% specificity at 100% sensitivity, and to distinguish nonmelanoma skin cancer from benign nevi with 87% specificity at 100% sensitivity. The power of skin cancer detection using electrical impedance is as good as, or better than, conventional visual screening made by general practitioners.
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| 4. |
- Aberg, P., et al.
(författare)
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Variation of skin properties within human forearms demonstrated by non-invasive detection and multi-way analysis
- 2002
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Ingår i: Skin research and technology. - : Wiley. - 0909-752X .- 1600-0846. ; 8:3, s. 194-201
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Tidskriftsartikel (refereegranskat)abstract
- Background: It is known that the properties of human skin vary locally. The purpose of this study was to investigate the properties of human volar forearms even further using advanced non-invasive techniques and numerical methods. Methods: The skin properties of human volar forearms were investigated using measurements of trans epidermal water loss and multifrequency electrical impedance. Eight sites on the forearms of 27 healthy volunteers were measured. The sites were oriented as squares, four sites on both left and right forearm, approximately 40-50 mm apart. Results: Analysis of variance showed significant differences for epidermal water loss (P < 0.01) and the skin impedance (P < 0.001) between the inner and outer sides of the arms. Additionally, parallel factor analysis of the full skin impedance spectra also showed that there are systematic differences between right and left arm (P < 0.01). Conclusions: It is crucial to design skin studies carefully in order to minimise the effects of the local skin properties of human skin.
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| 5. |
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| 6. |
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| 7. |
- Nyström, Josefina, et al.
(författare)
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Combined near-infrared spectroscopy and multifrequency bio-impedance investigation of skin alterations in diabetes patients based on multivariate analyses
- 2003
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Ingår i: Medical and Biological Engineering and Computing. - : Springer. - 0140-0118 .- 1741-0444. ; 41:3, s. 324-329
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Tidskriftsartikel (refereegranskat)abstract
- A group of 34 diabetic men, with different degrees of diabetes complications, including skin changes, were studied by near-infrared (NIR) spectroscopy and total body multi-frequency bio-impedance analyses (MFBIA-body). Skin reflectance spectra were measured with a fibre-optic probe in four locations (sites): hand, arm, leg and foot. As control subjects, a group of 23 healthy males were also measured. A combined multivariate analysis of the two types of spectrum was performed. It was concluded that the NIR method has the potential to detect diabetes-related skin conditions and also that the combination of the two techniques provides a higher potential for classification and discrimination of the skin conditions, with correct classification increasing from 63% to 85%.
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| 8. |
- Sundqvist, Kristina, et al.
(författare)
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Receptor Modeling of PCDD/FS in Sediment of the Sundsvall Bay, Sweden
- 2008
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Ingår i: Organohalogen Compounds. ; 70:1641-4
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Tidskriftsartikel (refereegranskat)abstract
- In the Sundsvall Bay area, located in the southern Bothnian Sea (a sub-basin of the Baltic Sea), industrial history have included a large variety of activities, from small sawmills to large pulp and paper mills as well as chloralkali production. Previously, several sawmills in the area used chlorophenol formulations for wood preservation, and these were contaminated by PCDD/Fs. Chloralkali production using graphite electrodes and bleaching of pulp using chlorine are manufacturing processes also known to have caused PCDD/Fs emissions. A chemical industry has been active in the area since the 1930s and an aluminum smelter was built in 1942. Aluminum production, like many high temperature processes, is known to produce PCDD/Fs.The aim of this study was to investigate the possibility of using receptor modeling for identification and apportioning of the major sources of PCDD/Fs in the Sundsvall Bay. The Sundsvall Bay was chosen as the first study area of this modeling technique along the Swedish coast since there are several possible sources of PCDD/Fs in the area and a relatively large number of sediment samples have been analyzed. Current PCDD/F emissions have been investigated by sampling river water, industrial effluent entering the bay and, in addition, soil from two contaminated sawmill sites.
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