BACKGROUND Differentiation between glioblastoma and brain metastasis is highly important due to differing medical treatment strategies. While MRI is the modality of choice for the assessment of patients with brain tumors, differentiation between glioblastoma and solitary brain metastasis may be challenging due to their similar appearance on MRI. PURPOSE To differentiate between glioblastoma and brain metastasis subtypes using radiomics analysis based on conventional post-contrast T1 -weighted (T1 W) MRI. STUDY TYPE Retrospective. SUBJECTS Data were acquired from 439 patients: 212 patients with glioblastoma and 227 patients with brain metastasis (breast, lung, and others). FIELD STRENGTH/SEQUENCE Post-contrast 3D T1 W gradient echo images, acquired with 1.5 and 3.0 T MR systems. ASSESSMENT Analysis included image preprocessing, segmentation of tumor area, and features extraction including: patients' clinical information, tumor location, first- and second-order statistical, morphological, wavelet features, and bag-of-features. Following dimension reduction, classification was performed using various machine-learning algorithms including support-vector machine (SVM), k-nearest neighbor, decision trees, and ensemble classifiers. STATISTICAL TESTS For classification, the data were divided into training (80%) and testing datasets (20%). Following optimization of the classifiers, mean sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUC) were calculated. RESULTS For the testing dataset, the best results for differentiation of glioblastoma from brain metastasis were obtained using the SVM classifier with mean accuracy = 0.85, sensitivity = 0.86, specificity = 0.85, and AUC = 0.96. The best classification results between glioblastoma and brain metastasis subtypes were obtained using SVM classifier with mean accuracy = 0.85, 0.89, 0.75, 0.90; sensitivity = 1.00, 0.60, 0.57, 0.11; specificity = 0.76, 0.92, 0.87, 0.99; and AUC = 0.98, 0.81, 0.83, 0.57 for the glioblastoma, breast, lung, and other brain metastases, respectively. DATA CONCLUSION Differentiation between glioblastoma and brain metastasis showed a high success rate based on postcontrast T1 W MRI. Classification between glioblastoma and brain metastasis subtypes may require additional MR sequences with other tissue contrasts. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:519-528.

Differentiation between glioblastoma, brain metastasis and subtypes using radiomics analysis.

Object 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. Methods 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. Results Overall, intraoperative confocal imaging ...

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

The primary purpose of intraoperative pathologist consultation (IC) is to guide immediate surgical management;1 ICs can provide surgeons with important information that may be used to modify or even terminate a surgical procedure. Frozen sections performed during ICs can also be used to establish the nature and extent of a lesion, to determine the status of surgical margins and to confirm that sampling of lesional tissue is sufficient for further investigations.2

Periodic review of the correlation between frozen section diagnosis and final diagnosis is useful for several reasons. It can serve as a measure of an institution’s quality of service.3 Once errors are identified, the potential cause of the frozen section error can be investigated, and measures can be implemented to help prevent similar occurrences. Errors can occur because of diagnostic misinterpretation (i.e., the pathologist may make a false diagnosis or miss the diagnosis on the frozen section slide); the frozen sections may not be taken from lesional tissue; or technical issues, such as tissue section folds or uneven staining, may preclude proper evaluation.1,2,4,5 The impact of frozen section errors on changes to diagnoses can also be investigated, and some studies have categorized these as false-positive or false-negative frozen section diagnoses.1,2,4,5

The accuracy of frozen section diagnosis can be documented by comparing the diagnosis made on the frozen sections to the final diagnosis made on the pathology specimen after review of both the frozen and permanent sections. Given the limited amount of tissue that can be submitted or sampled during frozen section examination, and given the technical quality of frozen sections compared with permanent sections, discrepancies can be expected between frozen section diagnoses and final diagnoses. The literature reports discordance rates between frozen section diagnoses and final diagnoses ranging from 1.4% to 12.9%; about 75% of studies report a discordance rate below 5%, with an overall median of 2.9%.5–30 Whereas most studies have focused on the discordance between frozen section diagnoses and final diagnoses, 1 study reported that errors impacting patient care, defined as frozen section errors that may have affected intraoperative patient management, occurred in 0.1% of the frozen sections performed.5

We report the results of a review of ICs performed in the Hamilton Regional Laboratory Medicine Program (HRLMP) in Hamilton, Ont., and add to the Canadian data. This review was performed by a panel of staff pathologists and senior pathology residents from the HRLMP academic hospitals. We assessed the discordance rate between frozen section diagnoses and final diagnoses, the causes of frozen section errors and the impact of change in diagnosis on patient care.

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Intraoperative pathology consultation: error, cause and impact

Cytology has been shown to be of great value in intraoperative consultations of central nervous system (CNS) pathology. Intraoperative smear cytology provides a rapid and reliable intraoperative diagnosis and guidance to the neurosurgeon during surgical resection and lesion targeting. It also helps the surgeon to monitor and modify the approach at surgery.

The current study was undertaken to assess the accuracy and utility of intraoperative consultations for cytomorphological diagnosis by smear technique and correlate with histopathological diagnosis.

A retrospective study of 326 cases of CNS intraoperative consultations was performed. Smears were prepared from the biopsy samples sent in isotonic saline for immediate processing and stained by the Haematoxylin and Eosin method. The cytomorphological features were noted and correlated with final histopathological diagnosis.

Concordance between the intraoperative diagnosis and the final diagnosis was seen in 83.7% of cases. We demonstrated >95% accuracy for glioblastomas and >89% accuracy for mennigiomas and schwannomas. A reduction of diagnostic accuracy was seen in oligodendrogliomas (60%) and anaplastic oligodendrogliomas (57.2%).

Smear technique is a fairly accurate, relatively safe, rapid, simple, easily reproducible, and cost effective tool to diagnose brain tumors. Smear cytology is of great value in intraoperative consultation of CNS pathology. Diagn. Cytopathol. 2011. © 2010 Wiley Periodicals, Inc.

Intraoperative squash cytology of central nervous system lesions: a single center study of 326 cases.

Context: Intraoperative cytology and frozen section play an important role in the diagnosis of neurosurgical specimens. There are limitations in both these procedures but understanding the errors and pitfalls may help in increasing the diagnostic yield. Aims: To find the diagnostic accuracy of intraoperative cytology and frozen section for central and peripheral nervous system (PNS) lesions and analyze the errors, pitfalls, and limitations in these procedures. Settings and Design: Eighty cases were included in this prospective study in a span of 1.5 years. Materials and Methods: The crush preparations and the frozen sections were stained with hematoxylin and eosin method. The diagnosis of crush smears and the frozen sections were compared with the diagnosis in the paraffin section, which was considered as the gold standard. Statistical Analyses Used: Diagnostic accuracy, sensitivity, and specificity. Results: The diagnostic accuracy of crush smears was 91.25% with a sensitivity of 95.5% and specificity of 100%. In the frozen sections, the overall diagnostic accuracy was 95%, sensitivity was 96.8%, and specificity was 100%. The categories of pitfalls noted in this study were categorization of spindle cell lesions, differentiation of oligodendroglioma from astrocytoma in frozen sections, differentiation of coagulative tumor necrosis of glioblastoma multiforme (GBM) from the caseous necrosis of tuberculosis, grading of gliomas in frozen section, and differentiation of the normal granular cells of the cerebellum from the lymphocytes in cytological smears. Conclusions: Crush smear and frozen section are complimentary procedures. When both are used together, the diagnostic yield is substantially increased.

Errors, limitations, and pitfalls in the diagnosis of central and peripheral nervous system lesions in intraoperative cytology and frozen sections.

Background: Intraoperative consultation for neurosurgical specimens can be difficult at times, despite the use of both frozen section and squash preparation. Various factors influence the diagnostic accuracy of these procedures. This study was conducted to evaluate reasons for discordant case results in neurosurgical intraoperative consultations and make a comparative analysis of these two commonly used methods to identify the possible pitfalls, errors, and limitations. Materials and Methods: All the neurosurgical cases received in the Department of Pathology for intraoperative consultation over a period of 3 years were studied retrospectively. The slides of frozen sections and squash preparation were retrieved and the diagnosis was compared with the final diagnosis given on paraffin-embedded sections. Results and Observations: A total of 6% of the cases were found to be discordant; these included angiomatous meningioma, Non-Hodgkins lymphoma, metastatic renal cell carcinoma, cerebellopontine angle fibrous meningioma, and craniopharyngioma. Highly vascular lesions, unavailability of squash preparation in a few cases and technical errors like thick smears, excessively crushed specimen, freezing, and cautery induced and crushing artifacts contributed to misdiagnosis. Conclusion: The discrepant cases need to be reviewed regularly by pathologists to familiarize themselves with the morphological changes and artifacts. The knowledge of possible errors could minimize misinterpretation and help in providing a more conclusive opinion to the operating surgeon.

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Challenges in neurosurgical intraoperative consultation.

Fungal infection is a major health concern as the clinical features are not very distinctive. Lack of rapid diagnostic techniques results in delay in diagnosis, which may even culminate in a fatal outcome. The fact that many pathogenic fungal organisms autofluoresce in hematoxylin and eosin (H and E)-stained sections under ultraviolet illumination led us to evaluate the role of autofluorescence as a rapid screening technique for fungal infections. The aim of the present study was to assess the value of autofluorescence as a screening method for detecting fungi on tissue sections and to compare the results of autofluorescence with conventional histochemical stains for fungi. Hematoxylin and eosin-stained slides of mycotic lesions were examined under fluorescent microscope and the findings were compared with results of Gomori's methenamine silver and periodic acid-Schiff stains. We found fungal autofluorescence in 63 out of 64 cases studied, with a sensitivity of 97.8% and specificity of 100% in comparison with fungal stains. This was statistically significant (P < 0.05). We conclude that autofluorescence can be used as a rapid screening method for identification of fungi in tissue sections as it does not require any other specialized staining procedure.

Ehtesham

Papers

Challenges in neurosurgical intraoperative consultation.

Autofluorescence: a screening test for mycotic infection in tissues.