DYNAMIC CONTRAST-ENHANCED MAGNETIC-RESONANCE-IMAGING OF THE BREAST COMBINED WITH PHARMACOKINETIC ANALYSIS OF GADOLINIUM-DTPA UPTAKE IN THE DIAGNOSIS OF LOCAL RECURRENCE OF EARLY-STAGE BREAST-CARCINOMA

RATIONALE AND OBJECTIVES. This study was designed to assess the effica cy of dynamic contrast-enhanced magnetic resonance imaging (MRI) of th e breast combined with pharmacokinetic analysis of gadolinium (Gd)-DTP A uptake in the diagnosis of local recurrence of early stage breast ca rcinoma. METHODS. Fifty women treated with breast-conserving surgery a nd radiotherapy underwent breast MRI, Dynamic magnetic resonance data obtained at four preselected slice locations were analyzed to examine Gd-DTPA uptake based on a pharmacokinetic model using three parameters : wash-in rate, wash-out rate, and amplitude of uptake, Synthetic imag es were produced from the above parameters and their derivatives-maxim um uptake and reciprocal of half the time to maximum, For each region of interest (ROI), median parameter values were calculated, The mean p ixel signal intensity of each ROI was plotted against time, and an enh ancement index was determined. RESULTS. Sixty ROIs were selected: 49 l esions were benign, and 11, malignant, Significant differences between benign and malignant lesions were found for the enhancement index (P < 0.0001), maximum uptake (P < 0.0001), amplitude of uptake (P < 0.000 1), wash-in rate (P = 0.03), wash-out rate (P = 0.01), acid the recipr ocal of half the time to maximum (P = 0.0005), The respective sensitiv ities and specificities were as follows: for the enhancement index, 1. 00 and 0.96; for maximum uptake, 1,00 and 0.96; for amplitude of uptak e, 0.91 and 0.94; for washin rate 0.82 and 0.47; for wash-out rate 0.9 1 and 0.59; and for the reciprocal of half the time to maximum, 1.00 a nd 0.51. CONCLUSIONS. Dynamic scanning proved essential for the detect ion and differential diagnosis of local tumor recurrence, Pharmacokine tic analysis of Gd-DTPA uptake can be used to produce parametric image s that retain the spatial resolution of the original images while prov iding additional information about lesion permeability and vascularity , and helping to avoid the observer variability associated with ROI an alysis.