Correlation between electrical conductivity and apparent diffusion coefficient in breast cancer: effect of necrosis on magnetic resonance imaging

Objectives: To investigate the correlation between conductivity and ADC in invasive ductal carcinoma according to the presence of necrosis on MRI. Methods: Eighty-one women with invasive ductal carcinoma ≥1 cm on T2-weighted fast spin echo sequence of preoperative MRI were included. Phase-based MR electric properties tomography was used to reconstruct conductivity. Mean ADC was measured. Necrosis was defined as an area with very high T2 signal intensity. The relationship between conductivity and ADC was examined using Spearman’s correlation coefficient (r). Multiple linear regression analysis was performed to identify factors associated with conductivity or ADC. Results: In the total group, conductivity showed negative correlation with ADC (r = –0.357, p = 0.001). This correlation was maintained in the subgroup without necrosis (n = 53, r = –0.455, p = 0.001), but not in the subgroup with necrosis (n = 28, r = –0.080, p = 0.687). The correlation between the two parameters was different according to necrosis (r = -0.455 vs -0.080, p = 0.047). HER2 enriched subtype was independently associated with conductivity (p = 0.029). Necrosis on MRI was independently associated with ADC (p = 0.027). Conclusions: Conductivity shows negative correlation with ADC that is abolished by the presence of necrosis on MRI. Key Points: • Electric conductivity showed negative correlation with ADC • However, the correlation was abolished by the presence of necrosis on MRI • HER2-enriched subtype was independently associated with conductivity • Necrosis on MRI was independently associated with ADC.