47 research outputs found

    Glioblastoma surgery imaging—reporting and data system: Standardized reporting of tumor volume, location, and resectability based on automated segmentations

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    Treatment decisions for patients with presumed glioblastoma are based on tumor characteristics available from a preoperative MR scan. Tumor characteristics, including volume, location, and resectability, are often estimated or manually delineated. This process is time consuming and subjective. Hence, comparison across cohorts, trials, or registries are subject to assessment bias. In this study, we propose a standardized Glioblastoma Surgery Imaging Reporting and Data System (GSI-RADS) based on an automated method of tumor segmentation that provides standard reports on tumor features that are potentially relevant for glioblastoma surgery. As clinical validation, we determine the agreement in extracted tumor features between the automated method and the current standard of manual segmentations from routine clinical MR scans before treatment. In an observational consecutive cohort of 1596 adult patients with a first time surgery of a glioblastoma from 13 institutions, we segmented gadolinium-enhanced tumor parts both by a human rater and by an automated algorithm. Tumor features were extracted from segmentations of both methods and compared to assess differences, concordance, and equivalence. The laterality, contralateral infiltration, and the laterality indices were in excellent agreement. The native and normalized tumor volumes had excellent agreement, consistency, and equivalence. Multifocality, but not the number of foci, had good agreement and equivalence. The location profiles of cortical and subcortical structures were in excellent agreement. The expected residual tumor volumes and resectability indices had excellent agreement, consistency, and equivalence. Tumor probability maps were in good agreement. In conclusion, automated segmentations are in excellent agreement with manual segmentations and practically equivalent regarding tumor features that are potentially relevant for neurosurgical purposes. Standard GSI-RADS reports can be generated by open access software

    Glioblastoma Surgery Imaging-Reporting and Data System: Validation and Performance of the Automated Segmentation Task

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    For patients with presumed glioblastoma, essential tumor characteristics are determined from preoperative MR images to optimize the treatment strategy. This procedure is time-consuming and subjective, if performed by crude eyeballing or manually. The standardized GSI-RADS aims to provide neurosurgeons with automatic tumor segmentations to extract tumor features rapidly and objectively. In this study, we improved automatic tumor segmentation and compared the agreement with manual raters, describe the technical details of the different components of GSI-RADS, and determined their speed. Two recent neural network architectures were considered for the segmentation task: nnU-Net and AGU-Net. Two preprocessing schemes were introduced to investigate the tradeoff between performance and processing speed. A summarized description of the tumor feature extraction and standardized reporting process is included. The trained architectures for automatic segmentation and the code for computing the standardized report are distributed as open-source and as open-access software. Validation studies were performed on a dataset of 1594 gadolinium-enhanced T1-weighted MRI volumes from 13 hospitals and 293 T1-weighted MRI volumes from the BraTS challenge. The glioblastoma tumor core segmentation reached a Dice score slightly below 90%, a patientwise F1-score close to 99%, and a 95th percentile Hausdorff distance slightly below 4.0 mm on average with either architecture and the heavy preprocessing scheme. A patient MRI volume can be segmented in less than one minute, and a standardized report can be generated in up to five minutes. The proposed GSI-RADS software showed robust performance on a large collection of MRI volumes from various hospitals and generated results within a reasonable runtime

    Volatile Organic Compounds Emitted by Fungal Associates of Conifer Bark Beetles and their Potential in Bark Beetle Control

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    High level of chromosome 15 aneuploidy in head and neck squamous cell carcinoma lesions identified by FISH analysis: limited value of beta2-microglobulin LOH analysis.

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    Item does not contain fulltextIn cancer research, loss of heterozygosity (LOH), defined by microsatellite markers, is frequently used in the identification of gene loss. Especially, genomic alterations in the human leukocyte antigen (HLA) genes and the beta2-microglobulin (beta2m) gene on chromosome 15 are of interest regarding their function in the immune system. Because LOH analysis detects any allelic imbalance and not just allelic loss, we evaluated the LOH analysis in 11 head and neck squamous cell carcinoma (HNSCC) lesions using fluorescence in situ hybridization (FISH). The 11 tumors were selected out of 53 HNSCC lesions based upon beta2m LOH analysis and beta2m expression. Centromere 1 and 15 FISH were developed to determine the chromosome 15 copy number. Sequence-based mutation analysis of beta2m was conducted on tumors without beta2m expression; no mutations in the coding sequences were found. For five HNSCC lesions with LOH and beta2m expression, centromere 15 FISH indicated gain rather than loss. In the majority of the 11 HNSCC lesions, FISH showed centromere 1 and 15 heterogeneity throughout the tumor. Moreover, FISH indicated a more complex chromosome 1 and 15 distribution than could be concluded from microsatellite LOH analysis. Our results show that microsatellite LOH analysis does not represent the beta2m gene copy number and support the results obtained from comparative genomic hybridization (CGH) studies. Conclusions on genomic alterations in tumors cannot be based on LOH data only but depend on the results of immunohistochemical staining, FISH, and CGH
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