Differentiation between ductal carcinoma in situ and mastopathy using dynamic contrast-enhanced magnetic resonance imaging and a model of contrast enhancement.

The purpose of this study was to retrospectively evaluate the feasibility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to differentiate between ductal carcinoma in situ (DCIS) and mastopathy by analyzing their time-intensity curves (TICs) using the two-compartment pharmacokinetic model with an assumption of instantaneous injection of contrast medium (TCPM). After the pre-contrast MRI was performed using a 1.5 T MRI system, DCE-MRI was performed four times after the intravenous administration of contrast medium. We set the volumes of interest (VOIs) on the tumor and normal mammary gland, and obtained the TICs in these VOIs. We calculated the following parameters by fitting these TICs to the equation derived from TCPM; the initial slope of the TIC (Slopeini), the area under the TIC (AUC), the time to peak enhancement (TTP) and the peak enhancement (PeakE). We calculated these parameters in both the lesion and normal mammary gland and the ratios of the parameters in the lesion to those in the normal gland (rSlopeini, rAUC, rTTP and rPeakE). There were significant differences in Slopeini (P=0.009), PeakE (P=0.019), rSlopeini (P=0.010), and rTTP (P=0.005) between DCIS and mastopathy. The areas under the receiver operating characteristic curve for Slopeini, PeakE, rSlopeini, and rTTP were 0.67±0.06 (P=0.009), 0.65±0.06 (P=0.019), 0.67±0.06 (P=0.01), and 0.68±0.06 (P=0.005), respectively. In conclusion, our results suggest that analysis of TICs obtained by DCE-MRI using TCPM appears to be useful for differentiating between DCIS and mastopathy.