New Hope in Brain Glioma Surgery: The Role of Intraoperative Ultrasound. A Review

Abstract

Maximal safe resection represents the gold standard for surgery of malignant brain tumors. As regards gross-total resection, accurate localization and precise delineation of the tumor margins are required. Intraoperative diagnostic imaging (Intra-Operative Magnetic Resonance-IOMR, Intra-Operative Computed Tomography-IOCT, Intra-Operative Ultrasound-IOUS) and dyes (fluorescence) have become relevant in brain tumor surgery, allowing for a more radical and safer tumor resection. IOUS guidance for brain tumor surgery is accurate in distinguishing tumor from normal parenchyma, and it allows a real-time intraoperative visualization. We aim to evaluate the role of IOUS in gliomas surgery and to outline specific strategies to maximize its efficacy. We performed a literature research through the Pubmed database by selecting each article which was focused on the use of IOUS in brain tumor surgery, and in particular in glioma surgery, published in the last 15 years (from 2003 to 2018). We selected 39 papers concerning the use of IOUS in brain tumor surgery, including gliomas. IOUS exerts a notable attraction due to its low cost, minimal interruption of the operational flow, and lack of radiation exposure. Our literature review shows that increasing the use of ultrasound in brain tumors allows more radical resections, thus giving rise to increases in survival.

Intraoperative MRI-guided Resection in Pediatric Brain Tumor Surgery: A Meta-analysis of Extent of Resection and Safety Outcomes

“…In particular, in benign histopathologic entities such as pilocytic astrocytoma, complete removal can be curative. 4 Established tools to achieve high rates of gross total resection (GTR) in glioma surgery are intraoperative ultrasound, 5 intraoperative magnetic resonance imaging (iMRI), [6][7][8] and 5-aminolevulinic acid (5-ALA). 9 In the typical pediatric histopathologic entities, poorer results of 5-ALA are reported.…”

Brain Mapping-Aided SupraTotal Resection (SpTR) of Brain Tumors: The Role of Brain Connectivity

“…iMRI with integrated functional neuronavigation is commonly used to achieve better visualization of residual tumor volume and to reassess neuronavigation during surgical manipulation to overcome brain shift ( 60 , 67 ). As an adjunct, IOUS with our without contrast enhancement (CEUS) is a valuable tools to distinguish tumoral tissue from normal brain parenchyma; notably, IOUS is more accessible than iMRI and it immediately allows a real-time visualization of tumoral tissue during surgical manipulation ( 68 ). As regards fluorescent dyes, 5-ALA is specifically accumulated by glioma cells and it is enlightened by intraoperative source of blue-light ( 10 , 52 , 53 , 69 ).…”

Focused Ultrasound in Neuroscience. State of the Art and Future Perspectives

“…From the interaction between ultrasound beams and cells, four main physical phenomena occur reflection, refraction, diffusion, absorption. In the last few decades, many studies showed how ultrasounds could be used not only for clinical or intraoperative diagnostic purposes also for therapeutics [ 1 ].…”