Introduction: Contrast-enhanced ultrasound (CEUS) is a dynamic and continuous imaging modality that offers a real-time, direct view of vascularization, flow distribution patterns of different types of lesions. Thanks to second-generation ultrasound-contrast agents, CEUS has become a well-established, live-imaging technique for many organs, but it has never been extensively used for brain imaging, mainly because of bone shielding to ultrasounds. To date, the reported use of intraoperative-CEUS imaging in neurosurgical procedures is very limited. Aim of the study is to provide the first dynamic and continuous intraoperative-CEUS evaluation of different brain lesions. Aim of the study is to provide the first dynamic and continuous intraoperative-CEUS evaluation of different brain lesions.

Methods: All patients included in the study underwent surgery for intracranial tumor with ultrasound guidance. CEUS imaging was obtained before resection of the lesion after microbubble contrast-agent intra-venous injection, using low-acoustic-power contrast-specific modes. A semi-quantitative offline inter-observer analisys had been performed in order to evaluate lesion visualization with CEUS and perfusion characteristics: afferent/efferent blood vessels, timing for wash-in and wash-out. All data were compared both to pre-op MRI and histopathology.

Results: Between December 2010 and December 2012, 58 patients underwent intraoperative-CEUS imaging while being operated on for different brain lesions. In all cases it was possible to visualize the lesion with CEUS. Main findings were: glioblastomas and metastasis: rapid arterious phase (5') with rapid wash out. Low grade glioma: slow arterious phase (10') with persistent parechymal phase, late wash-out. Meningiomas: rapid arterious phase (5-10') with persistent enhancement. All results are summarized in figure 1 and table 1. No adverse effects were observed.

Conclusions: Our study is the first extensive implementation of intraoperative-CEUS in neurosurgery, providing a dynamic and continuous real-time imaging of different brain lesions, through a direct visualization of the lesion, vascularisation pattern, flow distribution of different types of brain lesions.

Patient Care: Intraoperative-CEUS appears to be a fast, safe, dynamic, real-time, economic tool, which will possibly provide further insight in the pathology of brain lesions.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) understand CEUS imaging 2) evaluate its different features in brain tumor visualization 3) discuss CEUS role in tumor resection

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