The use of electrical impedance tomography to the differential diagnosis of pathological mammographic/sonographic findings.

Our study involved 870 eligible women with suspected pathological breast lesion discovered by mammography (MMG) or ultrasound examination (USG) which were recommended to pass histological examination to verify the diagnosis. All patients included in our study were divided into two age groups: the 1st group - patients older than 40 years (total of 724 patients) , the 2nd group - patients younger than 40 years (total of 146 patients). The purpose of our study was to analyze the possibilities of electrical impedance tomography (EIT) implementation to the differential diagnosis of pathologic lesions of the breast either solely, or in a combination with MMG/USG. The following results were obtained: in the 1st group the average specificity of MMG was 79.5%; when added EIT the average specificity decreased to 72.8%. The sensitivity of MMG, by contrast, increased from 87.8% when using it as an independent method to 94.5% when added EIT. In the 2nd group the average specificity of USG was 90.2%; when added EIT the average specificity decreased to 86.4%. Similarly, as in the 1st group the sensitivity of USG increased from 86.7% when using it as an independent method to 93.3% when added EIT.Analysis of false-negative results of electrical impedance tomography depending on the stage of the process has shown that as the earlier stage of the disease and as the smaller is the dimensions of the tumor, the higher is the number of false-negative results. In addition, we observed the dependence of the false-negative results of the tumor grade. The results of our study show that the use of EIT in addition to MMG/USG can improve the sensitivity of these methods and to increase the rate of early detection of breast cancer with minimal economic costs and highly qualified staff time expenditures.

Utilisation of electrical impedance tomography in breast cancer diagnosis.

BACKGROUNDS: Breast cancer presents a serious medical and social problem worldwide. Early detection is key to effective breast cancer treatment. Therefore, scientists are consistently looking for new diagnostic techniques that would be more efficient, easy to use and safe for the patient. The main task of this study was to evaluate the feasibility of a novel low-cost non-invasive technique called electrical impedance tomography (EIT) and to determine whether EIT can qualitatively supplement the existing traditional imaging techniques in the process of breast cancer diagnostics. PATIENTS AND METHODS: Randomly selected patients with mammographic and/or sonographic abnormalities were involved into the study. In total, 808 patients aged 18-94 (mean 54) years participated in the survey. Exclusion criteria involved previous breast surgery, breast core biopsy or fine needle aspiration within the last 1 and 3 months, respectively. Furthermore, patients with implanted electrically powered devices (cardioverter, pacemaker) and patients previously treated by chemo-radiotherapy were also excluded. The EIT examination was performed using the electrical impedance computer mammograph MEIK developed by the Institute of Radio Engineering and Electronics, Russian Academy of Sciences. RESULTS: The following results were obtained: sensitivity of EIT was 87%, X-ray mammography (MMG) 89% and ultrasonography (USG) 91%; specificity of EIT was 85%, MMG 91% and USG 84%. Negative predictive value (NPV) of all three modalities showed nearly equal values, with slight advantage of the USG. MMG had the highest positive predictive (PPV) value (83%), EIT had the lowest (63%). Sensitivity increased to 96% and 98%, respectively, when combinations EIT+MMG and EIT+USG were used. The specificity increased to 79% for EIT+MMG and 71% for EIT+USG. EIT+MMG and EIT+USG NPV remained the same. PPV was 65% and 58%, respectively for the EIT+MMG and EIT+USG combination. CONCLUSION: Our study findings are comparable to those of other similar studies. Although the EIT is a promising method and deserves close attention of specialists, it cannot replace MMG and/or USG examination as it does not provide information on structural changes to the breast. It can, however, provide very useful additional information about metabolic processes in the body. But in order to show its full potential some improvements should be held.