The International Workshop on Osteoarthritis Imaging Knee MRI Segmentation Challenge: A Multi-Institute Evaluation and Analysis Framework on a Standardized Dataset

Purpose: To organize a knee MRI segmentation challenge for characterizing the semantic and clinical efficacy of automatic segmentation methods relevant for monitoring osteoarthritis progression. Methods: A dataset partition consisting of 3D knee MRI from 88 subjects at two timepoints with ground-truth articular (femoral, tibial, patellar) cartilage and meniscus segmentations was standardized. Challenge submissions and a majority-vote ensemble were evaluated using Dice score, average symmetric surface distance, volumetric overlap error, and coefficient of variation on a hold-out test set. Similarities in network segmentations were evaluated using pairwise Dice correlations. Articular cartilage thickness was computed per-scan and longitudinally. Correlation between thickness error and segmentation metrics was measured using Pearson's coefficient. Two empirical upper bounds for ensemble performance were computed using combinations of model outputs that consolidated true positives and true negatives. Results: Six teams (T1-T6) submitted entries for the challenge. No significant differences were observed across all segmentation metrics for all tissues (p=1.0) among the four top-performing networks (T2, T3, T4, T6). Dice correlations between network pairs were high (>0.85). Per-scan thickness errors were negligible among T1-T4 (p=0.99) and longitudinal changes showed minimal bias (<0.03mm). Low correlations (<0.41) were observed between segmentation metrics and thickness error. The majority-vote ensemble was comparable to top performing networks (p=1.0). Empirical upper bound performances were similar for both combinations (p=1.0). Conclusion: Diverse networks learned to segment the knee similarly where high segmentation accuracy did not correlate to cartilage thickness accuracy. Voting ensembles did not outperform individual networks but may help regularize individual models.Comment: Submitted to Radiology: Artificial Intelligence; Fixed typo

A Comprehensive Study of the Electrostatic Discharge Sensitivity and Chargeability of Tris(carbohydrazide)zinc Perchlorate

Abstract: Most primary explosives are non-conductors, easily accumulate charge when contacting with and separating from other materials, and are sensitive to electrostatic discharge (ESD). In order to reduce the number of accidents caused by ESD initiation of primary explosives, studies on their electrostatic hazards are necessary. This work presents comprehensive experimental results of electrostatic discharge sensitivity and chargeability of tris(carbohydrazide)zinc perchlorate (ZnCP) under different conditions. The influences of the testing conditions, of devices, particle size, ambient temperature and relative humidity on the electrostatic discharge sensitivity and chargeability have been investigated in detail, and the quantitative regression equations obtained

CD90 and CD24 Co-Expression Is Associated with Pancreatic Intraepithelial Neoplasias.

Thy-1 (CD90) has been shown to be a potential marker for several different types of cancer. However, reports on CD90 expression in pancreatic intraepithelial neoplasia (PanIN) lesions are still limited where PanINs are the most important precursor lesion of pancreatic ductal adenocarcinoma (PDAC). Herein, we investigate candidate markers for PanIN lesions by examining the distribution and trend of CD90 and CD24 expression as well as their co-expression in various stages of PanINs. Thirty cases of PanINs, which were confirmed histopathologically and clinically, were used to evaluate protein expression of CD90 and CD24 by immunofluoresence double staining. CD90 was found to be mainly expressed in stroma around lesion ducts while not observed in acini and islets in PanINs. CD90 also showed increased expression in PanIN III compared to PanIN III. CD24 was mainly present in the cytoplasm and membrane of pancreatic ductal epithelia, especially in the apical epithelium of the duct. CD24 had higher expression in PanIN III compared with PanIN IIIIII or PanIN III. CD90 was expressed around CD24 sites, but there was little overlap between cells that expressed each of these proteins. A correlation analysis showed that these two proteins have a moderate relationship with PanIN stages respectively. These results suggest that co-expression of CD90 and CD24 may have an important role in the development and progression of PanINs, which is also conducive to early detection and treatment of PDAC

Representative images of CD90 (green) with CD45(red) both in PanIN III and PanIN III.

<p>Nuclei visualization was shown by staining DAPI (blue). CD45 was negative in PanINs. Scale bars = 100 μm.</p

Expression of CD24 (red) in normal and various PanIN tissues.

<p>Nuclei visualization was shown by staining DAPI (blue). CD24 presented weak or negative expression in acinar cells, and no staining was observed in pancreatic ductal epithelium in the normal goup. CD24 was mainly present in the cytoplasm and membrane of the pancreatic ductal epithelium, especially in the apical epithelium of the duct (arrow). Scale bars = 100 μm.</p

Three PanIN hispathological grades (HE).

<p>A:normal pancreas; B:PanIN III, minimal cytological atypia (arrow); C:PanIN III, nuclear polarity disappears, moderate cytological atypia (arrow); D: PanIN III, nuclear atypia hyperplasia, papillary or micro papillary morphology (arrow). Scale bars = 100 μm.</p

Comparison of staining score of CD90 and CD24 expression between PanIN and normal pancreas.

<p>A: CD90 expression; B: CD24 expression. *means <i>P</i><0.05;**means <i>P</i><0.01.</p

Co-expression of CD90 (green) and CD24(red) in PanIN.

<p>Nuclei visualization was shown by staining DAPI (blue). CD90 mainly presented in stromal cells, however, CD24 expressed in cytoplasm and membrane of pancreatic ductal epithelium. There was little overlap in all stages. Scale bars = 100 μm.</p