An Investigation Into Dielectric Testing for the Evaluation and Characterisation of Breast Tissue Using a Novel Time-Domain Bioimpedance Tool

Zedsen Limited has manufactured a TD-BIS scanner, which can measure electrical properties of different human tissue types. The equipment consists of two operational parts: a Charging Cradle and a Sensor Head. The Sensor Head is used to perform measurements on a client's breast. The Charging Cradle is used to charge and hold the Sensor Head between and after measurements, as well as to enable data transfer. A computerised system runs the TD-BIS scanner's associated Application (App) will guide the clinical user on completing the breast scan to ensure complete data collection.

The TD-BIS scanner capable of measuring electrical properties of breast tissue. A preliminary study in the UK evidenced the TD-BIS scanner's ability to identify lesions from healthy breast tissue based on differences in tissue electrical properties. In the proof-of-concept study, the TD-BIS scanner was able to identify invasive lesion, in situ lesions and benign breast changes (including cysts, AIDEP and fibroadenoma) ranging in size from as small as 0.5cm3 to larger than 1.5cm3. Further, the accuracy of lesion detection was impaired in breasts with higher density (BI-RAD scores C and D) . The proposed study aims to further investigate and validate previous results by utilising the TD-BIS scanner on a larger, more diverse cohort of patients and while exploring the effects of breast density on lesion detection.

Breast density is the amount of fibroglandular tissue compared with the amount of fatty tissue in the breast . Breast density if currently classified using a mammogram (MMG) according to the 4-point BI-RADS breast density category: A, entirely fatty; B, scattered areas of fibroglandular density; C, heterogeneously dense; D, extremely dense. Higher breast density (BI-RADS category of C or D) is a known risk factor for breast cancer .

MMG is the gold standard imaging modality used in breast cancer screening and diagnosis . While it contributes to increased survival rates of breast cancer patients through early detection, it has many limitations including exposure to ionising radiation, patient discomfort, and most notably, a decreased sensitivity in dense breasts. Just under half of all women, particularly those who are younger, pre- or perimenopausal or women of colour; have more dense breasts. Other imaging modalities such as Magnetic Resonance Imaging (MRI) and ultrasound are less affected by breast density but are limited by other factors such as accessibility, costs, semi-quantitative results and high false positive rates.

Dielectric imaging is emerging as a promising technique for breast cancer detection. As a principle it uses differences in electric properties called capacitance, specifically permittivity and conductivity, which measure any materials ability to store of move energy. There are cellular differences between breast tissue types (no-lesion, benign or malignant lesions) which has been shown to have an impact on the bioelectric properties. There is some evidence to suggest that this way of imaging a breast may also overcome some of the MMG limitations of detecting breast tissue types, within dense breasts. But these systems still require specialist equipment within hospitals.

Further, the existing method used to evaluate tumour response to neoadjuvant chemotherapy, is subjective. The response evaluation criteria in solid tumours (RECIST) 1.1 is the standard method used. It requires an experienced radiologist to choose the target lesions and measure changes in tumour size before and after treatment. The methods is limited due to inherent variability and errors in reported related to clinical efficacy, as well as only capturing size differences with no way to capture the change in tumour microstructure that occurs with effective treatment.

The prototype TD-BIS scanner was shown to capture the bioelectric signal of various types of breast tissue types in the first-in-human study. The prototype device has been refined in collaboration with clinical users and the proposed study will now invite a larger population of women who are attending a breast health clinic to be scanned with the TD-BIS scanner in addition to their standard of care breast health clinic appointment. Clinicians and patients will be blinded to the TD-BIS scanner outputs, and their clinical findings and results will be used as the ground truth.

The aim of the study is to determine the feasibility of using the improved TD-BIS scanner to identify the electrical properties of various breast tissues types. It will also be evaluated for its ability to classify breast density, differentiate lesion type, and the safety and tolerability of the device in a UK clinical population.