MR imaging-guided breast localization system with medial or lateral access.

Area of Science:

• Radiology
• Medical Imaging
• Surgical Navigation

Background:

• Accurate localization of suspicious breast lesions visualized exclusively by magnetic resonance (MR) imaging is crucial for effective biopsy.
• MR-guided needle localization systems aim to improve precision in targeting these lesions.

Purpose of the Study:

• To evaluate the accuracy of an MR-guided needle localization system for biopsy of MR-only lesions.
• To identify factors influencing needle placement error, including lesion and breast characteristics.

Main Methods:

• Utilized prospectively recorded and retrospectively reviewed data from 31 patients undergoing MR-guided needle localization for 35 lesions.
• Calculated needle and wire placement errors (x, y, z planes) before and after correction, correlating them with lesion variables, breast density, and histopathology.
• Employed univariate and multivariate linear regression analyses and paired t-tests for statistical correlation.

Main Results:

• The system demonstrated a mean uncorrected needle placement error of 5.6 mm in the z-plane, improving to 3.2 mm after correction.
• Factors significantly increasing uncorrected error included tissue shift in the z-plane (R=0.7), small lesion size (R=-0.59), and fatty breast density (P=.029).
• 46% of lesions were malignant, and 37% of needles required repositioning for z-plane error.

Conclusions:

• The MR-guided needle localization system is accurate for both medial and lateral approaches.
• Small lesion size, fatty breast density, and z-plane tissue shift are key factors affecting uncorrected needle placement accuracy.