Contrast-enhanced MR imaging of breast lesions and effect on treatment.

PURPOSE: To assess the value of local staging with preoperative magnetic resonance imaging (MRI) in patients with suspect breast lesions and the effect on therapeutic approach. MATERIALS AND METHODS: Two hundred and four consecutive women with suspect breast lesions on clinical examination (CE) and/or mammography (MX) and/or ultrasound (US) underwent preoperative contrast-enhanced MRI. Detection of multifocal, multicentric and bilateral breast cancer by all three imaging modalities was evaluated. Results of preoperative breast MRI were discussed with the treating surgeons. The type of therapeutic change after preoperative MRI was marked on a questionnaire (none, additional fine needle aspiration, core biopsy, open biopsy, wider excision, mastectomy) and considered 'necessary' or 'unnecessary' using final histopathological results as gold standard. RESULTS: In 170 patients, breast cancer was diagnosed. MRI detected 96% of multifocal disease and 95% of multicentric disease, whereas MX depicted 37 and 18%, and US 41 and 9% of them, respectively. All bilateral breast cancers were seen on MRI; both MX and US detected 56%. Findings of more extensive disease and unsuspected multiple breast cancer foci identified on MRI only, changed the therapeutic approach correctly in 30.6% of breast cancer patients. Nine unnecessary wider excisions and three unnecessary FNA/core biopsies were performed because MRI overestimated the number or size of malignant lesions. CONCLUSION: Preoperative breast MRI is an important adjunct to conventional imaging in the loco-regional staging of breast cancer and a useful tool in treatment planning.

Preoperative breast MRI in patients with invasive lobular breast cancer.

To investigate the use of MRI in preoperative characterization of invasive lobular breast cancer (ILC) and in detection of multifocal/multicentric disease. We retrospectively reviewed T1-weighted FLASH 3D precontrast and postcontrast MR images together with subtraction images of 26 women with histopathologically proven invasive lobular cancer. Two experienced radiologists described tumor patterns of ILC independently. MR findings of unifocal, multifocal, single quadrant and multiquadrant disease were correlated with results of other imaging techniques and compared with histopathological findings as gold standard. Most ILC presented on MRI as a single spiculated/irregular, inhomogeneous mass (pattern 1, n=12) or as a dominant lesion surrounded by multiple small enhancing foci (pattern 2, n=8). Multiple small enhancing foci with interconnecting enhancing strands (pattern 3) and an architectural distortion (pattern 4) were both described in three cases. There was one case of a focal area of inhomogeneous enhancement (pattern 5) and one normal MR examination (pattern 6). Unifocal and multifocal lesions were identified on MRI in four patients with normal conventional imaging. In nine women, multiple additional lesions or more extensive multiquadrant disease were correctly identified only on MRI. MRI may play an important role in the evaluation of patients with ILC, which is often difficult to diagnose on clinical examination and conventional imaging and more likely occur in multiple sites and in both breasts. However, false-negative MR findings do occur in a small percentage of ILC.

Breast MR imaging in a patient with unilateral axillary lymphadenopathy and unknown primary malignancy.

Bilateral invasive breast cancers were detected on MR imaging in a patient with left unilateral axillary lymphadenopathy and normal findings at physical examination, mammography, and ultrasound of both breasts. One spiculated and a second ill-defined enhancing lesion in the left breast as well as a superficial circumscribed lesion in the right breast were proven to be invasive malignancies. In patients with isolated axillary lymph nodes and occult primary malignancy, breast MRI can identify or exclude the breast as primary site, which proves the superiority and diagnostic benefit of this imaging method and also its contribution to the therapeutic approach.