A systematic review of the effectiveness and the diagnostic accuracy of intraoperative ultrasound in the resection of low-grade gliomas.

Objective: This systematic review aims to evaluate the effectiveness of intraoperative ultrasound (iUS) in achieving gross total resections (GTR) and identifying tumor remnants in low-grade glioma (LGG) surgeries.

Methods: A search of Medline, Cochrane, and Scopus databases until 8th August 2024 was performed to retrieve relevant studies, while reference lists were also scanned. Studies were selected based on predetermined inclusion and exclusion criteria, and their methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool.

Results: Thirteen studies were included: 1 prospective randomized controlled trial, 10 prospective studies and 2 retrospective studies. Of these, five studies had a high risk of bias, and eight had significant concerns regarding applicability. One study provided only mean volumes of tumor remnants, while the remaining 12 studies included a total of 352 patients. Eight studies used 2D B-mode iUS, and five used 3D navigated iUS. There was considerable variability in iUS characteristics, reference methods, and outcome measures. Linear array iUS generally demonstrated superior characteristics, and 3D iUS showed promising potential. Sensitivity ranged from 21.05% to 100%, and GTR percentages varied from 10.71% to 100%, while specificity ranged from 66.67% to 100%. Data on remnant volumes were available from only three studies.

Conclusions: From the available literature no safe assumptions on neither the diagnostic accuracy nor the efficacy of iUS in LGG resections can be made.