Neuropathological interpretation of stimulated Raman histology images of brain and spine tumors: part B

Abstract

Intraoperative histopathological examinations are routinely performed to provide neurosurgeons with information about the entity of tumor tissue. Here, we quantified the neuropathological interpretability of stimulated Raman histology (SRH) acquired using a Raman laser imaging system in a routine clinical setting without any specialized training or prior experience. Stimulated Raman scattering microscopy was performed on 117 samples of pathological tissue from 73 cases of brain and spine tumor surgeries. A board-certified neuropathologist — novice in the interpretation of SRH — assessed image quality by scoring subjective tumor infiltration and stated a diagnosis based on the SRH images. The diagnostic accuracy was determined by comparison to frozen hematoxylin–eosin (H&E)-stained sections and the ground truth defined as the definitive neuropathological diagnosis. The overall SRH imaging quality was rated high with the detection of tumor cells classified as inconclusive in only 4.2% of all images. The accuracy of neuropathological diagnosis based on SRH images was 87.7% and was non-inferior to the current standard of fast frozen H&E-stained sections (87.3 vs. 88.9%, p = 0.783). We found a substantial diagnostic correlation between SRH-based neuropathological diagnosis and H&E-stained frozen sections (κ = 0.8). The interpretability of intraoperative SRH imaging was demonstrated to be equivalent to the current standard method of H&E-stained frozen sections. Further research using this label-free innovative alternative vs. conventional staining is required to determine to which extent SRH-based intraoperative decision-making can be streamlined in order to facilitate the advancement of surgical neurooncology.

Toward digital histopathological assessment in surgery for central nervous system tumors using stimulated Raman histology

“…Similarly, Straehle et al described good neuropathological interpretability of SRH images for approximately 96% of cases included in a cohort of different CNS tumors. 4 According to neuropathological judgment, a histopathological diagnosis could be made for 92 of 94 (98%) cases on the basis of the SRH images in our study; in contrast, a histopathological diagnosis could not be obtained in 2 of our SRH images. Interestingly, both SRH images were acquired during resection of a lesion with a final histopathological diagnosis of cavernoma based on H&E images.…”

“…In the literature, the study by Straehle et al reported a diagnostic accuracy of 100% for SRH used to diagnose LGG and, interestingly, cerebral or spinal metastases. 4 However, the authors found a lower diagnostic accuracy of 88.9% for SRH when used to diagnose HGG and meningiomas (90.9%). 4 According to our data and the findings reported in the literature, the SRH technique is capable of visualizing the histopathological characteristics of suspected CNS tumors during surgery with an image quality comparable to that of conventional H&E images, which is generally accessible days after surgery during routine neuropathological workup.…”

“…The tissue samples (approximately 5 mm 3 ) were positioned on a custom slide and scanned with the SRH imaging system (NIO Laser Imaging System, Invenio Imaging Inc.), as described previously. 3,4 After approximately 3 minutes, digital histopathological images were available for further histopathological assessment without any staining procedure. After SRH analysis, all scanned tissue samples were transferred to the neuropathology department for histopathological workup.…”

“…3 Recent studies showed promising first results regarding the feasibility and diagnostic accuracy of SRH, which provides histopathological features comparable to those of conventional frozen sections with H&E stainings. [3][4][5][6] The scanning process takes approximately 3 minutes to provide digital images, and the SRH images are rapidly produced and digitally accessible online for histopathological assessment by neuropathologists. 3 Another major advantage is that the unprocessed scanned tumor samples can still be applied for conventional neuropathological workup after SRH investigation.…”

Advances, technological innovations, and future prospects in stereotactic brain biopsies

“…During the first experiments, they had to improve process optimization regarding the tissue treatment; nevertheless, it was easily implemented in the surgical workflow in a “plug-and-play” manner [ 44 ]. In a second study, the same team quantified the neuropathological interpretability in a routine clinical setting without specialized training [ 61 ]. They tested the device on 117 samples of pathological tissue from 73 patients and a neuropathologist assessed image quality by scoring subjective tumor infiltration and stated a diagnosis based on the SRH images.…”