Intraoperative Diagnosis Of Brain Tumors Research Articles

NIMG-54. CONFOCAL FLUORESCENCE ENDOMICROSCOPY: A PROSPECTIVE MULTI-CENTERED, ASSESSOR BLINDED PILOT STUDY FOR THE DIAGNOSIS OF BRAIN TUMORS

Abstract Frozen section analysis remains the gold standard for intraoperative diagnosis during brain tumor surgeries; however, it is associated with extensive time consumption and the potential for freezing artifacts. In recent years, confocal laser endomicroscopy (CLE) has been actively studied as a promising alternative to address these limitations of frozen section analysis. In this prospective, multi-centered, assessor-blinded pilot study, our aim was to evaluate the diagnostic effectiveness of cCeLL - Ex vivo, a second-generation CLE model, compared to frozen section analysis for brain tumor diagnosis. We enrolled a total of 55 patients with newly diagnosed brain tumors between October 2022 and December 2022. Biopsy samples were obtained during surgical resection, and each tissue sample was divided into three smaller samples for permanent section analysis, frozen section analysis, and imaging acquisition using cCeLL - Ex vivo. The efficacy of both frozen section analysis and cCeLL - Ex vivo was assessed by comparing their diagnoses to the results from permanent section analysis. The diagnostic accuracy of cCeLL - Ex vivo was slightly higher than that of frozen section analysis, with accuracies of 89.2% and 86.5%, respectively. Both methods demonstrated a sensitivity of 92.2%. Notably, cCeLL - Ex vivo exhibited a higher specificity of 70% compared to frozen section analysis, which had a specificity of 50%. Additionally, the mean time from sample preparation to diagnosis was significantly shorter in cCeLL - Ex vivo (13 min 17 sec) compared to frozen section analysis (28 min 28 sec). These results indicate the promising potential of cCeLL - Ex vivo as a complementary tool for intraoperative diagnosis of brain tumors. Future studies are expected to provide more evidence regarding the potential clinical utility of CLEs in clinical settings.

Intraoperative diagnosis of brain tumors: comparative characteristics of cytological and histological examination of gliomas

Intraoperative diagnosis of brain tumors: comparative characteristics of cytological and histological examination of gliomas

PATH-45. INTRAEPIGLIOM - RAPID SEQUENCING-BASED DIAGNOSIS OF BRAIN TUMORS

Abstract The intraoperative diagnosis of brain tumors remains a clinical challenge despite recent technological advances. The current clinical practice differentiates non-surgical brain tumors from those preferably treated with cytoreductive surgery employing intraoperative frozen section diagnostics. A detailed molecular diagnosis required for this classification task within the timeframe of a routine neurosurgical procedure is currently unavailable. We have analyzed a clinical cohort of several brain tumor entities using Nanopore long-read sequencing on two Oxford Nanopore Technologies sequencing platforms (MinION, PromethION). Since currently available molecular cancer classifiers such as the DKFZ methylation profiling classifier cannot be readily adapted to real-time sequencing analysis, we implemented a novel algorithm (MethyLYZR) to predict the underlying cancer type. Publicly available Illumina Infinium array data were used to train the classifier to distinguish 91 brain tumor classes. For validation of classification accuracy, we conducted a comprehensive validation strategy. Both nanopore platforms could sequence more than 5,000 pre-selected CpG within less than 20 minutes for most of our samples. When combining an optimized library preparation protocol with the time used for sequencing the minimal number of CpGs needed for classification, we saw sample-to-answer times of less than 1 hour – in many cases within 45 minutes - from receiving a fresh biopsy to a robust cancer type prediction. Comparing actual and predicted diagnoses resulted in a favorable error rate, indicating potentially highly clinical validity. Our real-time based molecular diagnostic algorithm enables, in most cases, a reliable diagnostic call within the timeframe of a typical neuro-oncological surgery. MethyLYZR as a predictive tool may allow us to adjust the surgical strategy and deliver the prognosis to our patients right after surgery, thus allowing for as-of-yet unexplored opportunities for the intraoperative application of individualized therapeutic modalities.

Squash Smear Technique in Rapid Intraoperative Diagnosis of Brain Tumors

The role of rapid intraoperative diagnosis is crucial to neurosurgeons to not only define surgical approach, but also to ensure that minimum injury is caused to normal structures surrounding the lesion. Intraoperative cytology has been shown to be an important diagnostic modality. Squash smears are gaining popularity with increasing use of stereotactic biopsies which give limited tissue yield. The study was designed to assess the accuracy of intraoperative squash smear in the rapid intraoperative diagnosis of brain tumors. 100 consecutive cases of CNS tumors in which the tissue was removed at craniotomy or burr-hole biopsy were studied. The age range of the cases varied from 1 to 80 years. The diagnostic accuracy of squash smears was found to be 91%. In all the cases, clinicoradiological correlation was done with smear diagnosis. Smears were stained with 1% toluidine blue/H&E. In all the cases, results were compared with the paraffin section prepared from tissue remaining after the squash smears were made. Immunohistochemistry/Immunocytochemistry was done as needed.

Evaluation of Intraoperative Cytological Smears for Diagnosis of Brain Tumors with Special Reference to Immunohistochemistry.

Context:Brain tumors are heterogeneous group of benign and malignant tumors of glial, meningeal, neuronal, embryonal, and lymphoid origin. Rapid intraoperative diagnosis of the nature of the tumor helps the surgeon to plan the extent of surgery and modify it accordingly.Aims:(1) To establish the validity and reliability of squash cytology in the intraoperative diagnosis of brain tumors. (2) To correlate with histopathological report and immunohistochemistry (IHC) profile.Settings and Design:Prospective, observational study.Subjects and Methods:prospective, observational study was conducted in the Department of Pathology in collaboration with the Department of Neurosurgery of a tertiary care hospital. One hundred and seven patients with symptomatic or radiologically detected brain tumors were included in the study. Intraoperative squash smears were stained with hematoxylin and eosin and rapid papanicolaou stain. Cytological diagnosis was recorded and communicated to the surgeon. Cytological findings were corroborated with histological findings subsequently. GFAP, Ki-67, and ER-PR IHC were used as additional markers.Statistical Analysis Used:Software used in statistical analysis of our study was MedCalc version 11.6 (Mariakerke, Belgium: MedCalc Software 2011).Results:A total of 107 cases were included in the study. Meningioma was the most common lesion. Overall sensitivity in our study to diagnose benign and malignant tumors was 94.7% and the specificity is 97.6% with positive and negative predictive value of 94.7% and 97.6%, respectively. Diagnostic accuracy was highest in pituitary adenoma.Conclusions:The combination of meticulous evaluation of clinical, radiological, and cytological findings helps in accurate and rapid diagnosis of brain tumors.

Rapid immunohistochemistry based on alternating current electric field for intraoperative diagnosis of brain tumors.

Rapid immunohistochemistry (R-IHC) can contribute to the intraoperative diagnosis of central nervous system (CNS) tumors. We have recently developed a new IHC method based on an alternating current electric field to facilitate the antigen-antibody reaction. To ensure the requirement of R-IHC for intraoperative diagnosis, 183 cases of CNS tumors were reviewed regarding the accuracy rate of diagnosis without R-IHC. The diagnostic accuracy was 90.7 % (166/183 cases) [corrected] in which definitive diagnoses were not provided in 17 cases because of the failure of glioma grading and differential diagnosis of lymphoma and glioma. To establish the clinicopathological application, R-IHC for frozen specimens was compared with standard IHC for permanent specimens. 33 gliomas were analyzed, and the Ki-67/MIB-1 indices of frozen specimens by R-IHC were consistent with the grade and statistically correlated with those of permanent specimens. Thus, R-IHC provided supportive information to determine the grade of glioma. For discrimination between glioma and lymphoma, R-IHC was able to provide clear results of CD20 and Ki-67/MIB-1 in four frozen specimens of CNS lymphoma as well as standard IHC. We conclude that the R-IHC for frozen specimens can provide important information for intraoperative diagnosis of CNS tumors.

Comparison of squash smears and frozen sections versus paraffin sections in the intra-operative diagnosis of central nervous system lesions

Background: Utility of squash cytology is well established in the intra-operative diagnosis of brain tumors, thereby guiding the neurosurgeon in the surgical management. A comparative study between squash smears, frozen sections and paraffin sections was done with an aim to study the diagnostic accuracy as well as limitations of these techniques. The present study was also undertaken to evaluate the discordant cases in intraoperative consultation of central nervous system (CNS) lesions. Methods: A total of 221 neurosurgical specimens were received in the Department of Pathology over three years duration, of which intra-operative consultation was requested in 110 cases. Both frozen and squash preparation was performed on all cases and stained with hematoxylin and eosin. An intra-operative diagnosis was made after examination of the squash smears and frozen section slides. The diagnosis given on squash smears and frozen section were then compared with final diagnosis given on paraffin-embedded sections. Immunohistochemistry was performed in a few diagnostically challenging cases. Results: This study compares the diagnostic accuracy of squash smears and frozen sections from 110 surgical specimens. The 110 cases included thirty six astrocytomas (32.7%), twenty four meningiomas (21.8%), twelve schwannomas (10.9%), two hematolymphoid tumors (1.8%), eight medulloblastomas (7.3%), three oligodendrogliomas (2.7%), four pituitary adenomas (3.6%), four ependymomas (3.6%), four metastatic tumors (3.6%), one paraganglioma (0.9%), two pineal parenchymal tumors (1.8%) and ten infections (9.1%). The accuracy of squash smears was 93.6%, and when combined with frozen sections the accuracy increased to 97.3%. Conclusion: Squash smears are simple, rapid, economical and very effective tool in the diagnosis of brain tumors. However, in few matrix rich/fibrous tumors like meningiomas and schwannomas, frozen sections are more useful. Hence, overall the combined use of squash smear and frozen section study increases the intra-operative diagnostic accuracy of CNS lesions.

Dye‐Enhanced Multimodal Confocal Imaging as a Novel Approach to Intraoperative Diagnosis of Brain Tumors

Intraoperative diagnosis plays an important role in accurate sampling of brain tumors, limiting the number of biopsies required and improving the distinction between brain and tumor. The goal of this study was to evaluate dye-enhanced multimodal confocal imaging for discriminating gliomas from nonglial brain tumors and from normal brain tissue for diagnostic use. We investigated a total of 37 samples including glioma (13), meningioma (7), metastatic tumors (9) and normal brain removed for nontumoral indications (8). Tissue was stained in 0.05 mg/mL aqueous solution of methylene blue (MB) for 2-5 minutes and multimodal confocal images were acquired using a custom-built microscope. After imaging, tissue was formalin fixed and paraffin embedded for standard neuropathologic evaluation. Thirteen pathologists provided diagnoses based on the multimodal confocal images. The investigated tumor types exhibited distinctive and complimentary characteristics in both the reflectance and fluorescence responses. Images showed distinct morphological features similar to standard histology. Pathologists were able to distinguish gliomas from normal brain tissue and nonglial brain tumors, and to render diagnoses from the images in a manner comparable to haematoxylin and eosin (H&E) slides. These results confirm the feasibility of multimodal confocal imaging for intravital intraoperative diagnosis.

In vivo intraoperative confocal microscopy for real-time histopathological imaging of brain tumors

Frozen-section analysis is the current standard for the intraoperative diagnosis of brain tumors. Intraoperative confocal microscopy is an emerging technology with the potential to visualize tumor histopathological features and cell morphology in real time. The authors report their findings using this new intraoperative technology in vivo with sodium fluorescein contrast during the course of 50 microsurgical tumor resections. Eighty-eight regions were visualized with confocal microscopy, and corresponding biopsy samples were examined with routine neuropathological analysis. The tumors studied included meningiomas, schwannomas, gliomas of various grades, and a hemangioblastoma. The confocal microscopic features of each tumor and of various artifacts inherent to the technology were documented. A pathologist working in a blinded fashion reviewed a subset of the images in a further evaluation of the usefulness of the device as a diagnostic tool. Overall, intraoperative confocal imaging correlated surprisingly well with corresponding traditional histological findings, including the identification of many pathognomonic cytoarchitectural features of various brain tumors. In the blinded study, 26 (92.9%) of 28 lesions were diagnosed correctly. Further study will be necessary for better definition of the role of intraoperative confocal microscopy as a routine adjunct for intraoperative brain tumor diagnosis.

Fluorescence Lifetime Spectroscopy and Imaging in Neurosurgery.

Clinical outcome of patients diagnosed with primary brain tumor has been correlated with the extent of surgical resection. In treating this disease, the neurosurgeon must balance between an aggressive, radical resection and minimizing the loss of healthy, functionally significant brain tissue. Numerous intra-operative methodologies and technological approaches have been explored as a means to improve the accuracy of surgical resection. This paper presents an overview of current conventional techniques and new emerging technologies with potential to impact the area of image-guided surgery of brain tumors. Emphasis is placed on techniques based on endogenous fluorescence lifetime contrast and their potential for intraoperative diagnosis of brain tumors.

Receptor-targeted quantum dots: fluorescent probes for brain tumor diagnosis

The intraoperative diagnosis of brain tumors and the timely evaluation of biomarkers that can guide therapy are hindered by the paucity of rapid adjunctive studies. This study evaluates the feasibility and specificity of using quantum dot-labeled antibodies for rapid visualization of epidermal growth factor receptor (EGFR) expression in human brain tumor cells and in surgical frozen section slides of glioma tissue. Streptavidin-coated quantum dots (QDs) were conjugated to anti-EGFR antibodies and incubated with target cultured tumor cells and tissues. The experiments were conducted first in human glioma tumor cell lines with elevated levels of EGFR expression (SKMG-3, U87) and then in frozen tissue sections of glioblastoma multiforme and of oligodendroglioma. The bioconjugated QDs used in the study were found to bind selectively to brain tumor cells expressing EGFR. QD complexed quickly to the cell membrane (less than 15 min), and binding was highly specific and depended on the expression level of EGFR on the cell membrane. Tissue experiments showed that only tumor specimens expressing EGFR were labeled in less than 30 min by QD complexes. These findings demonstrate that QD-labeled antibodies can provide a quick and accurate method for characterizing the presence or absence of a specific predictive biomarker.

Smear technique in the intra-operative brain tumor diagnosis: Its advantages and limitations

The role of intra-operative pathological diagnosis increases along with a development of minimally invasive neurosurgery, especially stereotactic and endoscopic techniques. The authors present their own experience with the cytological method and evaluate its usefulness in intra-operative diagnosis of brain tumors. Brain tumor biopsy specimens obtained during craniotomy from 217 patients were examined. The cytological preparations (smears) were stained with 1 % toluidin blue and/or with May-Grunwald-Giemsa stain. In 199 cases (92%) the cytological diagnosis was consistent with the histopathological one. A 99% sensitivity and 69% specificity were obtained. The histogenesis of gliomas was correctly established in 90% and their grade in 73% of cases. The most frequent diagnostic errors were: undergrading of gliomas (20), incorrect assessment of their histogenesis (10), diagnosis of low grade astrocytoma in a case of gliosis (3) and diagnosis of glioblastoma multi forme instead of metastatic carcinoma (2 cases). The most important advantages of cytological examination are rapidity, simplicity and relatively high diagnostic efficacy. Even very tiny specimens, especially of soft consistency are suitable for this technique, which is extremely important in operations of brain tumors localized in functionally important brain areas. In the authors' opinion this method still merits wider popularization in neurosurgical centers. [Neurol Res 1999; 21: 121-124]