Electrical impedance-based biopsy for prostate cancer detection

Abstract

Currently biopsy is considered the gold standard for diagnosis of prostate cancer in humans, although it samples only 19mm 3 volume of prostate, corresponding to 0.95% of a 50cm 3 prostate gland for a regular 12-core biopsy procedure. The aim of this study was to increase the sampling volume by incorporating electrical impedance spectroscopy (EIS) into the standard biopsy needle. Electrical impedance can act as a reliable biomarker for distinguishing malignant from benign tissues in human prostate. The EIS biopsy needle allows tip of the needle to act as sensor to measure the electrical impedance of the tissue core extracted. The sensitivity of the prototype device was evaluated in a series of saline bath experiments. We demonstrated that EIS biopsy needle senses 286.92 mm 3 of volume of the tissue on either side of the needle trajectory for each core, adding up to 2 X 12 X 286.92 = 6886.08 mm 3 or 13.8% of tissue's volume. Thus, measuring electrical properties in addition to core extraction is expected to enhance the sensitivity and specificity of the device. A few experiments have been conducted on ex vivo porcine samples to envisage EIS biopsy needle's ability in distinguishing two different kinds of tissues.

Incorporating a biopsy needle as an electrode in transrectal electrical impedance imaging

“…An insulating polyimide sheath (Miniature Polyimide Tubing, 0.810 mm ID, 0.861 mm OD, Part Number: SWPT-0319-30) was applied onto the surface of the needle (0.643 mm OD × 254 mm, Myco Medical, Reli Chiba Point Needles, CHE22G101) leaving only the tip of the needle (2 – 3 mm) uncovered [12]. The other end of the needle was connected to the TREIT data acquisition system (Fig.…”

Use of Bioelectric Impedance Analysis (BIA) as a new method to detect prostate cancer

“…The electrodes placement was done to create a restricted electric field in the prostate area and get more reliable results in terms of sensitivity as demonstrated by other authors. [7,8,11,12]. The novel probe was conceived to test the prostate tissue directly and consists of an electrode placement over a single rubber finger glove tip wearable over the rubber gloves normally used to detect prostate abnormalities.…”

“…Previous studies on BIA revealed enthusiastic results mainly in patients with aggressive cancers [5][6][7]. Studies conducted in the setting of prostate cancer in particular, were limited by the applicability of proper probes on the prostate gland surface and by the anatomic deep site in which the prostate is placed inside the pelvic bone girdle [8]. With the aim to reduce previous limitations in the applications of BIA test, we tested the performance of a novel endorectal probe in a series of consecutive patient candidate to prostate biopsy for suspicious prostate cancer.…”

Electrical impedance spectroscopy for prostate cancer diagnosis

“…The EISBx has radial and axial sensitivities of ~4mm and ~3mm, respectively [9]; because the probe was inserted sufficiently deep into the prostate (>4 mm), the saline solution surrounding the tissue did not have a significant influence on the measurements. The extracted biopsy sample is microtomed, stained with H&E, and microscopically evaluated by a pathologist to determine if benign or malignant cells are present in tissue core (Figure 3).…”

“…We have developed an electrical impedance spectroscopy (EIS) sensing biopsy (Bx) needle to record bipolar impedance measurements in tandem with tissue core extraction. We have demonstrated that this type of data has the potential to distinguish normal from abnormal tissue across a larger fraction of prostate volume than that sampled during conventional biopsy procedure [8] [9]. We present our most recent analysis of a 27 patient cohort evaluating how well these electrical properties discriminate cancer from non-cancer tissues in the prostate.…”