Prognosis in patients with glioblastomas (the most aggressive high-grade glioma) remains unfavourable. Tools for improving brain tumor surgery, in particular for gliomas, are increasing. There seems to be an agreement that achieving extensive resections, when done safely without jeopardizing neurological function, improves survival.

Ultrasound is currently used as a tool for providing 2D or 3D images for the purpose of tumor localization and resection control. For the use in resection control the resection cavity is filled with saline to provide acoustic coupling between the ultrasound transducer and tissue. However, attenuation of acoustic waves is very low in saline compared to the brain and this difference in attenuation is the cause of artifacts that may severely degrade the ultrasound images. Such artifacts are seen as high-intensity signal at the resection cavity wall and beyond, potentially masking small tumor remnants and generally making the interpretation of images more difficult.

This research group has developed an acoustic fluid intended for use in the resection cavity instead of saline. Tests in laboratory measurements have shown that the fluid reduces artifacts and has the potential to enhance ultrasound image quality in brain tumor surgery. The investigators expect that the acoustic fluid will make it easier to detect small tumor remnants near the end of an operation, thus increasing success of glioma surgery. The purpose of this study is to test the fluid during surgery for histopathologically proven glioblastoma to assess safety and efficacy.

Inclusion Criteria:

• A glioblastoma is suspected when there is a solitary brain tumour with ring-like contrast enhancement and oedema with no recent history (last 3 years) of primary tumour elsewhere
• In cases where histopathology is not known from previous biopsy or resection (i.e. diagnosis is suspected based on MRI findings and not from previous surgery) a tissue sample for frozen section is necessary. The fluid will only be used in cases where glioblastoma is suggested from this preliminary histopathological assessment.

Exclusion Criteria:

• Intended biopsy only (meaning: cases not suitable for resection)
• Other entities than glioblastoma is suspected
• Allergy to diary products and marine products
• Hypersensitvity to egg protein
• Hypersensitivity to soya or peanut protein
• Hypersensitvity to glycerol