Electrical impedance spectroscopy based biopsy needle for prostate cancer diagnosis and staging.

摘要

Diagnostic confirmation of prostate cancer is based on biopsy findings. In a standard 12-core prostate biopsy protocol, conventional biopsy needles sample only 0.95% (~0.228cm3) of a typical 24cm3 prostate gland. The primary objective of this study is to enhance the sensitivity of a standard biopsy protocol by gauging electrical properties of tissue in tandem with tissue core extraction for histopathology analysis. A conventional biopsy (Bx) needle was instrumented with an electrical impedance spectroscopy (EIS) sensor to interrogate the tissue volume surrounding the needle tip. The EIS-Bx device was evaluated in a series of saline bath and ex-vivo porcine experiments. It was found to sense an average volume of 0.286cm3 of tissue around the needle tip.;EIS measurements were recorded from 36 ex-vivo human prostates using the device and the extracted biopsy cores were histologically assessed. The magnitude of mean cancer resistivity was significantly higher than the benign tissues at all frequencies ranging from 100 Hz to 1 MHz (p < 0.05). Receiver operating characteristic (ROC) curves showed that the calibrated resistance rhoR (real component of complex resistivity) at 251 kHz was optimal for discriminating cancer from benign tissues. This parameter had 85.5% specificity (SP) and 56.7% sensitivity (SN). Similarly, 794 kHz is the optimal frequency for using calibrated reactance rhox (imaginary component of complex resistivity) to discriminate cancer from benign tissues. This parameter had 71.2% SP at 63.7% SN.;Spectral impedance parameters based (rhoinfinity, Deltarho , fc, alpha) representing tissue behavior were extracted by fitting the recorded EIS spectra into a single dispersion Cole-Cole model. The mean of parameter values were found to be greater for cancer tissues than benign tissues. rhoinfinity and fc provided the high contrast (p-values 1.93x10--5 and 9.56x10--5 respectively).;These results suggest that the electrical property sensing biopsy needle has potential of diagnosing cancer and improving biopsy sensitivity by detecting cancers that might be missed by the more systematic biopsy approach currently employed.