[Parelectric spectroscopy for noninvasive diagnosis of laryngeal tissue]

Under the influence of an external electrical field, every biological tissue displays characteristic parelectric properties that can be recorded by radiofrequency spectroscopy in a noninvasive contact mode. Parelectric spectroscopy was investigated for its utility as a complementary noninvasive diagnostic procedure in examinations of the larynx, in particular in terms of its ability to differentiate tissue properties. Parelectric spectroscopy was performed in 10 patients submitted to surgical ablation of vocal cord neoplasia under local or insufflation anaesthesia. Measurements were obtained in the area of the neoplasia, and in macroscopically normal tissue in the corresponding vocal cord. In all cases, intra-individual comparison with normal vocal cord tissue revealed lower dipole density and reduced mobility of the affected vocal cord. In addition, the difference between normal and pathological tissue in terms of the parelectric parameters increased with age. The absolute values of dipolar density and mobility revealed no tendency to correlate with different kinds of vocal cord neoplasia. Parelectric spectroscopy may be a useful additional diagnostic tool for monitoring the course of epithelial changes in the larynx.