Influence of histopathological factors on dynamic MR mammography.

Aim: To assess the histopathological background of enhancement mechanisms i n dynamic MR mammography studies. Methods: The dynamic MR mammography (MRM) examinations were done with a 1.5T MR imager (Magnetom Vision, Siemens) us ing a double breast coil and a coronal FLASH-3D sequence. Enhancement data were acquired during 9 minutes post contrast medium injection (Gd-DTPA, 0.2 mmol/kg). Acquisition time was 87 sec/slab. Early enhancement at the first post contrast measurement (E-1) and slope of wash-out (SE2-L) were calcula ted. In immunohistology, proliferation was assessed by the monoclonal antib ody Ki 67, capillaries were stained by a CD 31 antibody. Of a total of 48 o perated patients, 58 lesions and 46 surrounding tissues were evaluated. Res ults: Cellularity, capillary density and proliferation showed statistically significant correlations with E-1 (p < 0.01). In multiple regression analy sis, E-1 was significantly associated only with high cellularity (p = 0.002 ) and the combination of high cellularity and high microvessel density (p = 0.002); a negative slope of wash out was significantly associated only wit h malignant histology (p = 0.027). Conclusions: Our findings indicate a dir ect influence of cellularity and microvessel density on early enhancement. The expression of the proliferation marker Ki 67 was not an independent pre dictor for contrast enhancement.