Magnetic resonance imaging (MRI) has been used as an adjunct to breast imaging for over 20 years. It has gained increasing popularity for the diagnosis and staging of selected cases of breast cancer, which cannot be obtained with clinical examination and conventional imaging alone. The aim of this study was to identify cases where clinical management was altered by MRI findings.

All breast MRI examinations between April 2006 and March 2009 were identified from the Radiology Information System database (n = 183). Examinations for breast implant integrity assessment were excluded. The final number of patients in the study was 152. Mean age at presentation was 55 years; age range 19 to 89 years. The indications for imaging were: lobular carcinoma (n = 29, 19.1%); dense breasts (n = 16, 10.5%); axillary lymph node metastases with no breast primary (n = 13, 8.6%); Paget's disease (n = 2, 1.3%) and problem solving, including clinical/imaging discrepancy (n = 92, 60.5%).

The use of MRI for breast imaging changed the clinical management or intended surgical procedure in 74 (48.7%) patients. Of these, 52 (70.2%) had an alternative surgical procedure and 22 (29.7%) avoided an invasive biopsy. Four (2.6%) patients underwent an unnecessary invasive procedure due to MRI. MRI was most useful in the categories of problem solving (aiding diagnosis and staging of breast diseases) and in Paget's disease of the nipple (57 of 92 and 2 of 2 patients, respectively).

The use of MRI positively impacts on the clinical management of patients with breast cancer, and adds further evidence to support the use of such a modality in selected patients.