gms | German Medical Science

Objective: Neuronavigation is widely used in neurosurgical procedures, providing a low target registration error depending on the type of registration. However, surgical progress is associated with a decrease in accuracy caused by brain shift. This issue can be addressed by intraoperative live imaging. Here, we demonstrate the impact of navigated intraoperative 3D ultrasound (i3D US) in glioma surgery, comprising its ability of brain shift compensation and resection control.

Methods: 19 patients underwent glioma surgery utilizing intraoperative computed tomography (iCT)-based registration. The target registration error (TRE) was calculated. At least two navigated i3D US datasets were acquired with a co-registered high-resolution probe (frequency: 5 – 13 MHz; contact surface: 10 x 29 mm) before dural opening and after tumor resection, and additionally if necessary. Initial brain shift was demonstrated in live imaging.

Results: The mean ± standard deviation (SD) TRE was 0.90 ± 0.15 mm, demonstrating an excellent registration accuracy. Brain deformation could be visualized in live imaging. Patient age was 51.2 ± 18.8 years (mean ± SD). Mean tumor volume was 29.2 ± 35.3 cm3 in preoperative MRI vs. 28.6 ± 36.2 cm3 in pre-resectional US, which did not significantly differ (p = 0.4431, paired t-test). In 9 cases of intentional subtotal resection a tumor volume of 6.7 ± 11.2 cm3 was detected in post-resectional navigated i3D US. In 4 (21.1 %) cases of intended gross total resection post-resectional ultrasound demonstrated tumor remnants of a mean volume of 0.20 ± 0.05 cm3, resulting in an expansion of the resection extent.

Conclusion: Being widely available, cost and time efficient, navigated i3D US supplements multimodal neuronavigational setups with live imaging, providing information on brain deformation and tumor resection extent in glioma surgery.