1. Contrast-to-Noise Ratio (CNR) to quantify the reduction in noise (Time Frame - During ultrasound guided brain tumour resection): To show that ultrasound images obtained when using SonoClear ACF are less influenced by image artefacts compared to images obtained when using routinely used saline solution measuring the contrast-to-noise ratio (CNR) in the images.
2. Surgeons Image Rating (SIR) to assess the image quality (Time Frame - During ultrasound guided brain tumour resection): Quality assessment of the images is done by the core-lab in a blinded manner using the Surgeon Image Rating (SIR) scale, a 1-10 rating scale to score the quality of the image according to 3 questions at different time points during the operation. First timepoint being after craniotomy (no fluids involved). The second time point is when some tumour is left in the bottom of the deeper part of the resection cavity (approximately 80% of tumour removed), and the third time point being when the surgeon deems resection of the tumour to be completed.
3. Adverse events up to 30 days post procedure (Time Frame - safety data are collected up to 30 days post procedure): The primary safety hypothesis is to prove the primary safety event rate is less than 10%. A primary safety event is defined as any core lab determined major MRI finding when post-operative MRI is compared to pre-operative MRI that was found by the DMC to be serious and probably or definitely related to the study device OR any DMC determined serious adverse event that is probably or definitely related to the study device that occurs within 30 days of the procedure. Success is demonstrated by observing 0 of these events out of 37 subjects exposed to SonoClear ACF. This is equivalent to a two-sided p-value less 0.05 for the alternative hypothesis that the primary safety event rate in subjects undergoing tumor resection using ACF is less than 10%.
