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Whole-tumor histogram and texture features of the ADC and fractional anisotropy maps are useful for predicting the -mutation and 1p/19q-codeletion status in World Health Organization grade II gliomas.

BACKGROUND AND PURPOSE: Isocitrate dehydrogenase (IDH) wild-type lower-grade gliomas (histologic grades II and III) with epidermal growth factor receptor (EGFR) amplification or telomerase reverse transcriptase (TERT) promoter mutation are reported to behave similar to glioblastoma. We aimed to evaluate whether MR imaging features could identify a subset of IDH wild-type lower-grade gliomas that carry molecular features of glioblastoma. MATERIALS AND METHODS:In this multi-institutional retrospective study, pathologically confirmed IDH wild-type lower-grade gliomas from 2 tertiary institutions and The Cancer Genome Atlas constituted the training set (institution 1 and The Cancer Genome Atlas, 64 patients) and the independent test set (institution 2, 57 patients). Preoperative MRIs were analyzed using the Visually AcceSAble Rembrandt Images and radiomics. The molecular glioblastoma status was determined on the basis of the presence of EGFR amplification and TERT promoter mutation. Molecular glioblastoma was present in 73.4% and 56.1% in the training and test sets, respectively. Models using clinical, Visually AcceSAble Rembrandt Images, and radiomic features were built to predict the molecular glioblastoma status in the training set; then they were validated in the test set. RESULTS:In the test set, a model using both Visually AcceSAble Rembrandt Images and radiomic features showed superior predictive performance (area under the curve ¼ 0.854) than that with only clinical features or Visually AcceSAble Rembrandt Images (areas under the curve ¼ 0.514 and 0.648, respectively; P , . 001, both). When both Visually AcceSAble Rembrandt Images and radiomics were added to clinical features, the predictive performance significantly increased (areas under the curve ¼ 0.514 versus 0.863, P , .001).CONCLUSIONS: MR imaging features integrated with machine learning classifiers may predict a subset of IDH wild-type lowergrade gliomas that carry molecular features of glioblastoma.ABBREVIATIONS: AUC ¼ area under the receiver operating characteristic curve; cIMPACT-NOW ¼ Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy; GBM ¼ glioblastoma; LASSO ¼ least absolute shrinkage and selection operator; RFE ¼ recursive feature elimination; SVM ¼ support vector machine; TCGA ¼ The Cancer Genome Atlas; VASARI ¼ Visually AcceSAble Rembrandt Images; WHO ¼ World Health Organization A mutation in the isocitrate dehydrogenase (IDH) gene is a major classifier that leads to the stratification of gliomas with significantly different survival rates among the lower-grade gliomas (World Health Organization [WHO] grades II and III) as well as glioblastomas (GBMs). 1-4 IDH wild-type tumors, which account for ,30% of the histologic grade II and III gliomas, show worse prognoses than those with the IDH mutation. 1,5,6 Previous studies have reported heterogeneous clinical outcomes among the IDH wild-type lower-grade gliomas according to a variable combination of genetic profiles. [7][8][9] Recently, the Consortium to Inform Molec...

Based on the facts that AZ31 magnesium alloy can be blow formed just like superplastic aluminum alloys and that most superplastic alloys fail by cavitation, the present study was undertaken to investigate the cavitation behavior of a fine-grained AZ31 sheet during blow forming at the elevated temperature. Other points of interest included the much lower strain rate and temperature dependencies of the magnesium alloy compared with conventional superplastic alloys. It was also aimed to find if cavitation in the AZ31 alloy can be suppressed by hydrostatic pressure, as is the case in most superplastic alloys. Interestingly, the application of hydrostatic pressure did not increase the blow formability of AZ31 sheet, even though it reduced the degree of cavitation. A possible reason for this behavior is discussed.