PHARMACOKINETIC ANALYSIS OF GD-DTPA ENHANCEMENT IN DYNAMIC 3-DIMENSIONAL MRI OF BREAST-LESIONS

The purpose of this study was to demonstrate that dynamic MRI covering both breasts can provide sensitivity for tumor detection as well as s pecificity and sensitivity for differentiation of tumor malignancy, Th ree-dimensional gradient echo scans were used covering both breasts. B efore Gd-DTPA bolus injection, two scans were obtained with different flip angles, and after injection, a dynamic series followed. Thirty-tw o patients were scanned according to this protocol. From these scans, in addition to enhancement, the value of T1 before injection was obtai ned, This was used to estimate the concentration of Gd-DTPA as well as the pharmacokinetic parameters governing its time course, Signal enha ncement in three-dimensional dynamic scanning was shown to be a sensit ive basis for detection of tumors. In our series, all but two mammogra phically suspicious lesions did enhance, and in three cases, additiona l enhancing lesions were found, two of which were in the contralateral breast, The parameter most suited for classification of breast lesion s into benign or malignant was shown to be the pharmacokinetically def ined permeability kappa(31), which, for that test, gave a sensitivity of 92% and a specificity of 70%. Our three-dimensional dynamic MRI dat a are sensitive for detection of mammographically occult breast tumors and specific for classification of these as benign or malignant.