gms | German Medical Science

Objective: For robotic guided manipulation in soft tissue an adequate optical sensor is required. In ophthalmology optical coherence tomography (OCT) is a well established non-contact diagnostic tool for examination of surfaces. It was also possible to visualise brain tumors in animal studies and in human ex vivo samples. In our present study we systematically evaluated the diagnostic value of OCT when used ex vivo in different kinds of intracranial tumor tissue compared to healthy brain tissue.

Method: In accordance with the vote of the local ethics committee we examined ex vivo human tumor tissue samples from 10 patients. All samples were analysed with OCT (Thorlabs CALLISTO Spectral Domain OCT) directly after removal, then after paraffin embedding and finally directly in sections after H&E staining. Histopathological evaluation was performed and compared with OCT images. Two investigators blinded to the results of each other stated the degree of match between the two imaging modalities as perfect, moderate, minimal.

Results: The histopathological diagnosis of the samples was: glioblastoma multiforme n=3, astrocytoma n=1, cerebral metastasis (pulmonary cancer) n=1, meningeoma (WHO grade I) n=2, meningeoma (grade II) n=1. The morphological comparison focused on tissue structure all OCT samples were stated as perfect match with the histological sections in all ten cases. Both the direct OCT images, the probe after paraffin embedding and the one after staining allowed the detailed detection of structural differences between the different tissues.

Conclusions: In ex vivo analyses OCT is a reliable method for the scanning of brain and tumor tissue. As a non-contact method the integration in neurosurgical equipment is technically possible. Despite of these promising results further investigations with different tissue samples and regarding the integration into the work flow of tumor resection are necessary.