Why do purely intraductal cancers enhance on breast MR images?

On the basis of the results of the animal study performed by Jansen et al and clinical observations, there is compelling evidence to suggest that the imaging phenotype of a ductal carcinoma in situ (DCIS) lesion (its detectability at mammography and MR imaging, specifically the presence or absence of calcifications on mammograms and the presence or absence of calcifications and the degree of their enhancement on MR images) conveys important biologic information that will be useful when guiding DCIS treatment.