P2-10-08: Electrical Impedance Imaging Characteristics of Nodular and Edematous-Infiltrative Forms of Breast Cancer.

Abstract

Abstract Introduction: The purpose of this research is to establish diagnostic criteria of electrical impedance mammography, which are typical for nodular and diffuse forms of breast cancer. Materials and Methods: From 2008 to 2011, we examined 558 patients, 34 of whom had various forms of breast cancer (BC). All the patients were examined with electrical impedance potential mammography utilizing the electrical impedance computer mammograph MEIK, which enables to acquire images of 3-D conductivity distribution layers within mamma's tissues up to 5 cm depth. Group I comprised 27 women suffering from nodular forms of BC. Among them 9 women without clinical signs of the disease were put into subgroup I&a. 19 patients having significant clinical signs, such as edema, inflammation and infiltration, were put into subgroup Ib. Group II included 6 patients with diffuse BC. 102 patients without any mammary gland disease were put into the control group. Both visual and quantitative assessment of electrical impedance mammograms (EIM) was conducted. Result: Distinctions of kind were revealed between EIMs of the abovementioned patient groups. In case of nodular BC both general and local changes were observed in EIMs. General changes include deformation of mamma's contour, hyperimpedance contour and displacement of inner structures. Local changes comprise focal changes of electrical conductivity in form of an- or isoimpedance areas and hyperimpedance contour on the border of the tumor and surrounding tissue. In EIM mammograms of 100% patients belonging to subgroup Ia only local changes of electrical conductivity were detected in a form of animpedance area presented on several scan planes in the location corresponding to the tumor (electrical conductivity index >0.95), while there were no general changes in the image. The size of lesions detected in this group was less than 1 cm. Clinical signs of the decease were always present in group Ib patients. EIMs of these patients revealed both general and various local changes. Visual estimation of images revealed deformation of the mammary gland contour in 50% of the cases, subcutaneous fat infiltration - in 61%, anatomic changes with displacement of internal structures in 78%, perifocal infiltration in 94%. The quantitative analysis established the following: mean electrical conductivity index of a healthy mammary gland, as a rule, exceeded the index of mean electrical conductivity of the affected one; and the index of the mean electrical conductivity of a tumor exceeded the index of mean electrical conductivity of the affected gland almost twofold. EIMs of 100% of the patients with diffuse (edematous-infiltrative) BC revealed typical general changes of electrical conductivity: electrical conductivity of the affected mammary gland is considerably lower than that of the healthy one as well as lower than that of the age norm. This results in the intense dark EIM and significant change of electrical impedance anatomy. Conclusions: The revealed peculiarities of the electrical impedance images during various forms of the infiltrating BC growth correlate with the pathological-physiological phases of the tumor development. The article is illustrated with electrical impedance mammograms (EIMs) and tables. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-10-08.