DIAGNOSIS OF NONPALPABLE BREAST-LESIONS B Y DYNAMIC MRI - RESULTS OF A PROSPECTIVE AND MULTICENTRIC TRIAL

Aim: To determine the accuracy of dynamic contrast-enhanced subtractio n MRI to diagnose nonpalpable breast lesions in a prospective multicen ter study. Material and methods: From June to November 1994, 72 patien ts had a surgical biopsy for a nonpalpable breast lesion and a preoper ative dynamic MR after an informed consent was obtained. MR examinatio ns were performed on 0.5, 1 and 1.5T MR unit. Each center underwent dy namic sequences either in spin or gradient echo in T1 weighted images obtained in less than two minutes before and after injetcion of Gadoli nium-DOTA. The presence /absence of contrast enhancement within two mi nutes after injection of Gadolinium were considered as positive/negati ve findings respectively. Results: These 72 women had mammographic (n= 80) or ultrasonographic lesions (n=2). Mammograms showed mass (n=23), asymmetrical density (n=2), architectural distorsion (n=8), clustered microcalcifications (n=47) or was normal (n=2). Dynamic Breast MR imag ing showed early contrast enhancement in 44 malignant lesions (sensiti vity : 89.8%) and 13 benign lesions (specificity : 60.6%). Five intrad uctal carcinoma of comedo (n=1) or non-comedo (n=4) type did not demon strate any early contrast enhancement. Conclusion: This prospective mu lcentric study confirms the high sensitivity of dynamic breast MRI wha tever the type of MR unit or sequences.