Purpose: To describe new techniques for percutaneous biopsy with use of an open-configuration magnetic resonance (MR) imaging system with integrated frameless stereotaxic guidance tools.
Materials and methods: In 28 patients, biopsy was performed in which the image plane was interactively controlled by the position of a hand-held probe attached to the biopsy needle. An icon integrated into the image was used to guide needle advancement in three planes orthogonal to the needle. In vitro measurements of spatial accuracy were also performed.
Results: Diagnostic tissue was retrieved in 25 of 28 patients. The system was most accurate near the isocenter with a maximum measured error of 3.1 mm within a sphere of radius 2.5 cm about the isocenter.
Conclusion: MR-guided biopsy with a frameless stereotaxic technique is safe and accurate. Image feedback is near real time, and the procedure is interactive. These techniques may be used to perform MR-guided biopsies and to place probes for MR-guided therapies.