Impact Of Clinical And Lesion Characteristics On The Results Of Mr-Guided Wire Localizations Of The Breast Using An Open 1.0-T Mri System

Purpose: Preoperative magnetic resonance (MR)-guided wire localizations are warranted in patients with suspicious focal breast lesions on MR mammographic findings without equivalent in x-ray mammography and ultrasonography. The study was performed to assess the impact of clinical parameters, tumor size, and target localization on the procedural characteristics in magnetic resonance imaging (MRI)-guided wire localizations of breast lesions using an open 1.0-T open MR system.Material and Methods: The clinical, radiological, and histological characteristics of all 347 patients and all 394 interventional procedures performed in a 6-year interval were extracted from the clinical files. Two board-certified senior radiologists evaluated the impact of target localization and the size on the interventional results in the available 302 image data sets. Patient characteristics, lesion characteristics, and interventional results were statistically correlated in subgroup analyses.Results: A total of 387 of the 394 MR-guided wire localizations (98.2%) were technically successful. In 7 cases (2.3%), the intervention was aborted because the suspicious finding of the diagnostic MR mammography could not be visualized during the intervention. Minor complications occurred in 13 interventions (3.3%). The histological workup of the operative specimen showed benign results in 226 of the 394 interventions (57.4%) and malignant findings in 154 wire localizations (39.1%). The mean (SD) length of the interventional procedure time defined as the time interval between the start of the first and of the last MRI sequence as documented in the electronic MRI data sets was 24.6 (8.4) minutes. Patient age, medical history, and the anticipated risk for developing breast cancer and a simultaneous known carcinoma did not affect the technical success and complication rates and the interventional procedure time. A total of 60 targets (19.5%) were located in the retromamillary zone, 89 targets (28.9%) in the peripheral zone, and 1 target (0.3%) near the chest wall. The maximum diameter was 1 to 5 mm in 64 lesions (21.2%), 6 to 10 mm in 136 lesions (45.0%), 11 to 15 mm in 56 lesions (18.6%), and 16 mm or greater in 46 lesions (15.2%). A total of 23 of the 100 histologically proven invasive carcinomas had a maximum MRI diameter of 1 to 5 mm (23.0%) and 38 (38.0%) of 6 to 10 mm.Conclusions: Magnetic resonance-guided wire localizations of suspicious breast lesions using an open high-field MR system are a clinically safe and feasible method even in small target lesions and anatomical regions that are usually considered difficult to access.