PL01.5.A Towards modernizing intraoperative histopathological assessment in brain and spinal tumors - Comparison of the novel Stimulated Raman Histology with conventional H&E staining
Authors: Wadiura L I , Kiesel B , Roetzer-Pejrimovsky T , Mischkulnig M , Vogel C , Hainfellner J A , Woehrer A , Roessler K , Widhalm G 
Published: September 2022

Abstract

Background
By intraoperative analysis of fresh frozen sections, neuropathologists provide important information of different brain and spinal tumors to the neurosurgeon during surgery. This facilitates characterization of these tumors intraoperatively to optimize the surgical strategy and patient management. However, preparation and staining are time consuming using conventional techniques of intraoperative fresh frozen section. Stimulated Raman Histology (SRH) was introduced as novel technique providing high-resolution digital images of unprocessed tissue samples directly in the operating room comparable to conventional histopathological images. Additionally, SRH images are fast and easily accessible by neuropathologists. Recently, first data showed promising results on the accuracy and feasibility of SRH in comparison to conventional H&E staining.

Material and Methods
In a time period of 4 months, patients with different brain or spinal tumors who underwent neurosurgical resection or open/stereotactic biopsy at the Dept. of Neurosurgery, Medical University Vienna were included in this study. Tumor tissue samples were collected intraoperatively whenever safely possible for analysis with SRH. Subsequently, unprocessed tissue samples were scanned by SRH, and intraoperative histopathological images were created directly in the operating room within a few minutes. All collected tissue samples were then sent for routine neuropathological workup. In an overall analysis, SRH images and H&E staining of all patients were analyzed separately by two board certified neuropathologists. Information on age, localization and suspected diagnosis was provided in each case in order to simulate the situation of intraoperative fresh frozen section. In a next step the technical feasibility and diagnostic accuracy of SRH was calculated.

Results
In this study, tissue samples of 95 patients who underwent neurosurgical resection or open/stereotactic biopsy of different brain and spinal tumors were collected intraoperatively and analyzed by SRH. In total, 31 gliomas, 30 meningiomas, 19 metastases, 7 neurinomas and 8 rare tumors were analyzed. In the present study the use of SRH was technically feasible in all cases and could be easily integrated in the neurosurgical workflow to provide rapid digital histopathological images for the analyzing neuropathologists. According to our data, SRH provided high diagnostic accuracy (&gt;95%) in the investigated different brain and spinal tumors.

Conclusion
Based on our preliminary data the technical use of SRH is feasible and showed a high rate of diagnostic accuracy in a large series of different brain and spinal tumors. By using this promising technique, we intend to modernize intraoperative histopathological assessment by providing rapid digital images of brain and spinal tumors to optimize the management of these patients.