Improving Ultrasound Images in Brain Tumour Surgery With the Use of an Acoustic Coupling Fluid Mimicking Brain Tissue: a Phase II Technical and Safety Study

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 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. The artificial signal enhancement can potentially mask small tumor remnants and is generally making the interpretation of images more difficult.

This research group has developed an acoustic coupling 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. Three different concentrations of the acoustic coupling fluid have been tested in a phase 1 study that included 15 patients with glioblastoma. The concentration that provided the optimal ultrasound images, from qualitative and quantitative inspection, is used in the current phase II study. This study is a randomized controlled trial aiming to include 82 patients with glial brain tumours. Its purpose is to test the fluid during surgery of glial brain tumours to further investigate safety and efficacy.