title: Non-invasive and microinvasive electrical impedance spectra of skin cancer - a comparison between two techniques.
abstract: OBJECTIVE
  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.
authors.affiliation: Division of Medical Engineering, Karolinska Institutet, Huddinge, Sweden. peter.aberg@labmed.ki.se
authors.forename: Peter
authors.initials: P
authors.lastname: Aberg
authors.forename: Paul
authors.initials: P
authors.lastname: Geladi
authors.forename: Ingrid
authors.initials: I
authors.lastname: Nicander
authors.forename: Johan
authors.initials: J
authors.lastname: Hansson
authors.forename: Ulf
authors.initials: U
authors.lastname: Holmgren
authors.forename: Stig
authors.initials: S
authors.lastname: Ollmar
mesh_terms: D002280:Basal Cell Carcinoma / Q000175:diagnosis* / Q000503:physiopathology; D003937:Diagnosis, Differential; D017097:Electric Impedance; D006801:Humans; D008545:Melanoma / Q000175:diagnosis* / Q000503:physiopathology; D009506:Nevus / Q000175:diagnosis* / Q000503:physiopathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000503:physiopathology; D013057:Spectrum Analysis / Q000379:methods*