The purpose of this study is to determine whether performing MRI of the breast will improve breast cancer management by reducing the number of biopsies and in case of malignancy allowing one-stage surgical excision of the tumor.

Each year 7000 women present with nonpalpable suspicious breast lesions on mammography in the Netherlands. In the usual care situation, these lesions are detected by mammography and ultrasonography and pathologically characterized by analysis of large core needle biopsy material. In case of malignancy, these lesions are surgically removed. First, a wire is placed in the breast with the tip of the wire within 1 cm of the tumor and then the surgeon follows the wire and removes the lesion. Unfortunately about 25% of women require more that one surgical procedure to remove all tumorous tissue. This is caused by incorrect presurgical diagnosis of the extent and invasiveness of the disease (multifocality, multicentricity, lymph node involvement). We hypothesize that MR mammography will improve presurgical diagnosis and differentiation of lesions and thereby decrease the number of invasive surgical procedures (primary outcome) and number of invasive biopsies (secondary outcome).

Inclusion Criteria:

• patients with a nonpalpable, mammographically suspicious breast lesion (BI-RADS 3, 4 or 5)
• referred for large core needle biopsy
• 18 to 75 years

Exclusion Criteria:

• previous breast surgery or radiation therapy of the breast less than 9 months before MR mammography
• pregnant or lactating
• claustrophobia or adiposity ( > 130 kg)
• general contraindications for MRI
• unable to maintain prone position for one hour
• medically unstable patients