Fig 1.
Positioning of the patient in the iMRI-scanner and setup of coils.
The head of the patient with mounted frame and localizers is placed into the lower half of the 4-channel send/receive coil (double arrow). Due to the fact that the standard head coil (upper and lower part) does not accommodate the whole package, a flexible coil is used as upper half (black single arrow). This coil assembly was tested extensively prior to commissioning of the iMRI and yields good signal-to-noise ratios.
Fig 2.
Setup of anesthesia equipment in the iMRI scanner.
The MR-capable ventilator (Dräger Fabius MRI, Drägerwerke, Lübeck, Germany) is positioned outside the 30 mT area (dark line) while the monitoring hardware has to be kept outside the 20 mT area (light yellow line).
Table 1.
Demographics of subjects in both study cohorts.
Table 2.
Location of biopsy targets.
Fig 3.
Procedure duration stratified by imaging modality.
The duration of the procedures (time spent in the stereotactic frame) was significantly influenced by the imaging modality used to acquire the stereotactic dataset (One-way ANOVA, p < .000). Post-hoc testing (LSD-Bonferroni) showed significant differences between each individual imaging modality with exception of the CT/MRI pair. Procedures performed with intraoperative CT (iCT) required the least amount of time (median 110 min) followed by iMRI-based biopsies in second place (median 120 min). Imaging performed outside the OR (CT and MRI) considerably increased overall procedure time.
Table 3.
Postoperative imaging, hematoma and neurologic status in the iMRI cohort.
Table 4.
Postoperative imaging, hematoma and neurologic status in the control cohort.
Table 5.
Summary of complications.