gms | German Medical Science

Objective: To present our intraoperative low-field magnetic resonance imaging (ioMRI) technique for stereotactic brain biopsy in various intracerebral lesions.

Method: Seventy-eight consecutive patients underwent stereotactic biopsies with the PoleStar N-20/N-30 ioMRI system and data were evaluated retrospectively. Biopsy technique included ioMRI before surgery, followed by insertion of the biopsy cannula in the lesion based on the calculated trajectory. IoMRI confirmed accurate placement before biopsy and after surgery to exclude intraoperative complications. Statistical analysis was performed to compare subgroups using Excel and SPSS statistic software.

Results: In all patients stereotactic biopsy was possible with a mean intraoperative surgery time of 86.2 ± 28.6 minutes and a mean hospital stay of 11.6 ± 4.6 days. In 97.4% (n=76) histology was conclusive representing 58 brain tumors and 18 other pathologies. 5 patients were biopsied before without conclusive diagnosis and all biopsies were conclusive this time. Mean cross-sectional lesion size in MRI T1 with contrast (n=64) was 6.9 ± 5.7 cm² and in lesions without T1 contrast enhancement (n=14) T2 mean cross-sectional lesion size was 5.5 ± 3.9 cm². Mean distance from the cortex surface to the lesion was 3.4 ± 1.2cm. One patient suffered from a postoperative wound dehiscence, neither clinically or radiologically significant hemorrhage after surgery nor intraoperative complications occurred.

Conclusions: Low-field ioMR-guided frameless stereotactic biopsy accurately diagnosed different intracerebral lesions with rare complications for the patient and within an acceptable surgery time and hospital stay. In repeated non-conclusive biopsies in particular, low-field ioMRI offers a technique for arriving at a diagnosis.