gms | German Medical Science

Objective: Image-guided resection of intracranial lesions has become well established in most neurosurgical centers. Intraoperative MRI (ioMRI) and conventional low frequency intraoperative ultrasound (lfioUS) are the most commonly used intraoperative imaging modalities. The impact of high-frequency intraoperative ultrasound (hfioUS), even though highly beneficial in peripheral nerve surgery has not been assessed so far. The aim of the study was to evaluate sensitivity and accuracy of hfioUS based on a histopathological assessment in comparison to lfioUS and ioMRI.

Method: We provide the first report of an integration of hfioUS into a neuronavigation system and describe the typical technique for applying the registered hfioUS probe intracranially. After microsurgical gross total resection, we assessed the accuracy and sensitivity for detecting residual tumor by using hfioUS, lfioUS or ioMRI. Correlations of imaging results and histopathological findings in navigated biopsies from the resection cavity were evaluated. 19 histopathological specimens in 10 patients were assessed.

Results: Image quality of hfioUS exceeded lfioUS and showed higher resolution than ioMRI. In three cases pathological remnants could only be detected using hfioUS. hfioUS showed the highest sensitivity for detection of residual tumor tissue intraoperatively. Accuracy to detect pathological tissue was 74% with ioMRI, 50% with lfioUS and 95% with hfioUS.

Conclusions: Navigated hfioUS can be used as a safe and precise tool for intracranial image-guided resection control. The accuracy and sensitivity of the hfioUS clearly exceeds a modern lfioUS commonly used for intracranial procedures.The level of tissue detail, accuracy and sensitivity for tumor detection using hfioUS is higher than with ioMRI.