Intraoperative power Doppler ultrasonography with a contrast-enhancing agent for intracranial tumors

Object. The goal of this study was to evaluate intraoperative power Doppler ultrasonography when used with a contrast-enhancing agent for operations on intracranial tumors. Methods. Forty intracranial tumors were examined using power Doppler ultrasonography with a galactose microparticle-based ultrasonographic contrast-enhancing agent during operations on the brain. The tumors included 37 intracranial neoplasms (14 gliomas, six meningiomas, three hemangioblastomas, two malignant lymphomas, three other primary neoplasms, nine metastatic tumors, and three nonneoplastic lesions). All patients also underwent computerized tomography and magnetic resonance imaging, and all but three of the patients underwent digital subtraction (DS) angiography. Before injection of the ultrasonographic contrast agent, intra- and peritumoral power Doppler flow signals were detected in 32 of the intracranial tumors. After the injection, the signals were enhanced in blood vessels around the tumors and in the tumor parenchyma in 36 tumors. The duration of contrast enhancement continued for 70 to 365 seconds (mean 251.8 +/- 69 seconds) after the injection. Among the tumors, hemangioblastomas displayed particularly strong contrast enhancement. In these intracranial tumors, the echo signals obtained using contrast-enhanced power Doppler ultrasonography correlated with DS angiographic staining. Power Doppler ultrasonograms with the appropriate contrast agent provided better data on the precise real-time position of the tumors and their relationship to adjacent vessels than Ultrasonograms obtained before the injection of the contrast agent. Conclusions. Intraoperative power Doppler ultrasonography performed using a contrast-enhancing agent can facilitate intraoperative real-time navigation and assessment of the intratumoral vasculature and peritumoral vessels, particularly for tumors having abundant vessels such as hemangioblastomas.