Detection of cervical intraepithelial neoplasia using impedance spectroscopy: a prospective study.

OBJECTIVE

To compare cervical impedance spectrometry in the cervical epithelium of women with cervical intraepithelial neoplasia (CIN) and normal epithelium.

DESIGN

Prospective observational study.

SETTING

Colposcopy clinic, Jessop Wing, Royal Hallamshire Hospital, Sheffield, UK.

POPULATION

Eighty-seven women referred to colposcopy with a moderate or severely dyskaryotic smear.

METHODS

A pencil probe incorporating four gold electrodes was used to measure an electrical impedance spectrum from cervical epithelium. Colposcopy examinations, including probe positioning, were recorded by video to allow for correlation between results obtained from colposcopic impression, histopathological examination of colposcopically directed punch biopsies and the impedance measurements.

MAIN OUTCOME MEASURES

Cervical impedance derived parameters R, S and C were assessed to see if there was a significant difference in values obtained in CIN and normal squamous epithelium. Analysis was based upon matching the electrical components measured to those identified by cellular modelling as being most sensitive for premalignancy.

RESULTS

From normal epithelium through CIN 1 to CIN 2/3, R decreased by a factor of 4.5, S increased by a factor of 2.5 but C remained unchanged.

CONCLUSIONS

Cervical impedance spectrometry provides a potentially promising screening tool with similar sensitivity and specificity to currently used screening tests, but with the potential advantage of providing instant results. Further work is currently being undertaken to improve the probe in its clinical use.