Purpose
Magnetic resonance imaging (MRI) can detect clinically and mammographically occult breast lesions. Several techniques have been developed to allow localization and selective tissue sampling of these lesions. In this study we report the results of MRI-guided needle localization of suspicious breast lesions by using a freehand technique in a 0.5-T open magnet.
Material and methods
Preoperative MRI-guided single needle localization was performed in 220 patients with 304 breast lesions at our hospital between January 1997 and July 2004. All localization procedures were performed in an open 0.5-T Signa-SP imager, with the patient in prone position by using a phased array breast coil. In all patients MRI compatible hookwires were placed in a non-compressed breast by using a freehand technique. MRI findings were correlated with pathology and follow-up
Results
MRI-guided needle localization was performed for a single lesion in 150 patients, for two lesions in 56 patients, and for three lesions in 14 patients. Histopathologic analysis of these 304 lesions showed 104 (34%) malignant lesions, 51 (17%) high risk lesions, and 149 (49%) benign lesions. The overall lesion size ranged from 2.0-65.0mm (mean 11.2mm). No direct complications occurred. Follow-up MRI in 54 patients showed that 2 (3.7%) lesions were missed by surgical biopsy.
Conclusion
MRI-guided freehand needle localization is simple and accurate, the detection rate of malignant lesions (34%) is in accordance with the results of mammographically or US-guided needle localizations. An advantage of the freehand technique compared to grid localization is the ability to localize lesions in the anterior breast, the axillary region and near the chest wall.