PURPOSE: To investigate the effect of contrast material-enhanced magne
tic resonance (MR) imaging on staging of breast cancer in patients wit
h mammographically or clinically suspected tumor. MATERIALS AND METHOD
S: One hundred seventy-six patients underwent breast MR imaging at 1.5
T before excisional biopsy of a suspicious mammographic or palpable a
bnormality. Diagnostic imaging studies in patients with biopsy-proved
or presumed breast carcinoma were reviewed. RESULTS: Sixty-four patien
ts met the study criteria. MR imaging enabled detection of all 57 inva
sive breast cancers and nine of 15 in situ cancers. In 22 patients (34
%), MR imaging depicted one or more cancers not visible at mammography
, 13 (20%) of which were unsuspected multifocal or diffuse disease. As
a result of the increased sensitivity of MR imaging compared with tha
t of mammography, clinical staging and subsequent treatment were alter
ed in seven patients (11%). CONCLUSION: MR imaging allows detection of
mammographically and clinically occult foci of carcinoma in patients
with suspected breast cancer.