Article
Contrast enhanced ultrasound during brain tumor surgery – on the path to resection control
Kontrastmittelunterstützter Ultraschall bei Hirntumor-Operationen – eine neue Methode der Resektionskontrolle
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Published: | April 11, 2007 |
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Objective: The aim of this study was to adapt ultrasonographic techniques developed for brain perfusion in cerebral ischemia diagnostics into an intraoperative setting during neurosurgical brain tumor resection. It was intended to use tumor perfusion for online navigation and resection control. The aim of this study was to evaluate the feasibility of the method for delineation of the tumor and for resection control in the intraoperative setting.
Methods: During surgery, patients underwent several contrast-enhanced ultrasonographic investigations (Phase Inversion Harmonic Imaging, fitted model function). An endocavity-curved array [6.5EC10, 6.5 MHz] was used. The ultrasound contrast agent Sonovue® (Bracco) was administered intravenously as a bolus injection. During off-line analysis, time-intensity curves as well as perfusion maps were calculated and parameters such as peak intensity were locally extracted to characterize perfusion. At the end of the tumor resection, a final examination was done and compared to postoperative MRI or CT data sets.
Results: Twenty patients (age 18-76, mean 57 years) with brain tumors of different histology (gliomas, metastasis and meningiomas) were investigated with contrast-enhanced ultrasonography during surgery. In two patients no images could be analysed due to technical problems. In 18 cases the contrast enhancement was detectable and tumor identification was possible, 16 tumors could clearly be differentiated from normal brain and surrounding structures. Overall tissue differentiation with contrast agent was superior compared to conventional B-mode ultrasound imaging. In the first 6 patients, the results of the comparison with postoperative radiological examinations showed a good correlation in terms of resection control.
Conclusions: Intraoperative contrast-enhanced ultrasonography enabled visualization of cerebral tumors in high spatial resolution. Especially in displaying tumor borders, this technique could emerge to a low cost solution for intraoperative resection control.