Anwendbarkeit und Stellenwert der stimulierten Raman Histologie in der Epilepsiechirurgie kortikaler Malformationen

Intraoperative SRH is applicable for near real-time tissue analysis of cortical malformations following an adjusted workflow. Core diagnostic elements, i.e. cortical architecture and layering, neuronal orientation and atypical cell types, can be detected. Correlation with standard diagnostic techniques remains essential for future assessment of the diagnostic value of this promising alternative in epilepsy surgery of cortical malformations.

Overall 61 SRH images from cortical samples of 28 patients were analyzed using a Raman imaging system (Invenio Imaging Inc.). N=21 patients underwent tailored, navigation-guided lesionectomy due to intractable epilepsy with and without cortical malformation, for comparison normal access tissue to distant lesions (n=8) was analyzed. The established technique for near real-time SRH so far has been optimized for tissue analysis in tumor surgery using squash preparation. For analysis of cortical integrity or malformation, however, tissue collection and preparation require certain consideration. We advanced the workflow of tissue preparation within the operation tract, slicing cortical samples on a vibratome for immediate label-free SRH analysis. For diagnostic neuropathological correlation, the scanned tissue slice and adjacent samples were H&E-stained and immunolabelled (NeuN, neurofilament H (SMI-32), Calretinin, Parvalbumin, Vimentin, glial fibrillary acidic protein).

Our newly established workflow enables the application of intraoperative, near real-time SRH for the assessment of cortical integrity or malformation. The sliced tissue preparation enables label-free identification of cortical architecture and layering, axonal directionality, the gray-white matter boundary, and atypical cell types. To estimate the diagnostic value of this innovative technique for complementary intraoperative decision-making and classification of pathology, the unconventional H&E-based neuropathological diagnostic of FCD requires further training integrating standard immunolabelling.

Intraoperative SRH is applicable for near real-time tissue analysis of cortical malformations following an adjusted workflow. Core diagnostic elements, i.e. cortical architecture and layering, neuronal orientation and atypical cell types, can be detected. Correlation with standard diagnostic techniques remains essential for future assessment of the diagnostic value of this promising alternative in epilepsy surgery of cortical malformations.