Intraoperative contrast-enhanced ultrasound-assisted resection of brain tumors: a systematic review and meta-analysis

Given the critical importance of optimizing the extent of resection (EoR) in brain tumor surgery, intraoperative imaging techniques continue to evolve, enhancing tumor localization and margin delineation to enable maximal safe resection. Among these, intraoperative contrast-enhanced ultrasound (iCEUS) has recently been introduced into neurosurgical practice, with emerging evidence supporting its role in improving EoR. This systematic review and meta-analysis aim to evaluate the impact of iCEUS on the EoR in intracranial tumor surgery.

The literature was searched for studies on iCEUS use in intracranial tumor resection. The primary endpoints were the gross total resection (GTR) rate among iCEUS patients and its comparison with non-iCEUS patients. The secondary endpoint was the ultrasound contrast agent (UCA)-related adverse events (AEs). Subgroup analyses were performed for all gliomas and specifically for high-grade gliomas (HGG).

Five studies with 193 patients, including 106 (54.1%) undergoing iCEUS-assisted resection, were analyzed. The GTR rate in iCEUS-assisted cases was 81.13% (95% CI: 70.41%-91.84%; I² = 51%), significantly higher than in non-iCEUS cases (OR: 5.37; 95% CI: 2.41-11.97; I² = 0%). Among patients with gliomas (all grades), the GTR rate was 76.12% (95% CI: 58.82%-93.84%; I² = 61%), while in the HGG subgroup, it reached 79.26% (95% CI: 61.39%-97.13%; I² = 37%). No UCA-related AEs were reported.

iCEUS is a valuable intraoperative imaging tool with the potential to improve GTR rates in brain tumor surgery. Further research, particularly randomized controlled trials, is needed to clarify its impact on resection and survival outcomes across tumor types and to establish its comparative effectiveness against other intraoperative imaging modalities.