Introduction: Current stereotactic brain biopsy techniques have limitations, including the lack of real-time imaging to assess trajectory and targeting, dependence on intraoperative pathology consultation to verify lesional tissue and the need for a skin incision. We describe a novel brain biopsy device that addresses these shortcomings through the integration of intraoperative magnetic resonance (MR)-Imaging (iMRI) with a frameless percutaneous stereotactic frame.
Methods: Clinical, imaging and histologic data in the largest case series to date of 20 consecutive patients who underwent brain biopsy using a real-time MR-imaging stereotactic brain biopsy system were analyzed. All patients selected for the procedure had small (< 1.5 cm) targets and/or targets near or within eloquent structures (e.g. thalamus, adjacent to major vascular structure).
Results: Mean age was 45.8 years (range, 29 to 60 years). Real-time MR-imaging permitted concurrent display of biopsy cannula trajectory and tip during placement to target (Figure 1). Mean target depth of biopsied lesions was 71.3 mm (range, 60.4 mm to 80.4 mm). Targeting accuracy analysis revealed a mean radial error of 1.3 mm (±1.1 mm; S.D.), mean depth error of 0.7 mm (±0.3 mm; S.D.) and a mean absolute tip error of 1.5 mm (±1.1 mm; S.D.) (Figure 2). There was no correlation between target depth and absolute tip error (Pearson product-moment correlation coefficient [r= 0.22]). All biopsy cannulae were placed to target with a single penetration and resulted in a diagnostic specimen in all cases.
Conclusions: The ability to place a biopsy cannula under real-time MR-imaging guidance allowed for on-the-fly alterations of cannula trajectory and/or cannula tip placement. Intraoperative MR-imaging confirmed acquisition of lesional tissue, precluding the need for intraoperative pathology consultation. Real-time imaging during MR-guided brain biopsy provides precise safe and accurate targeting of brain lesions, and is especially recommended for lesions near eloquent structures.
Patient Care: Application of this technology to stereotactic brain biopsy could eliminate misdiagnosis secondary to faulty targeting, provide real-time adaptability for needle trajectory, confirm accurate biopsy cannula position and provide immediate imaging of complications.
Learning Objectives: To assess the feasibility, accuracy and safety of real-time magnetic resonance (MR)-imaging-compatible frameless stereotactic brain biopsy