Atypical Teratoid Rhabdoid Tumor: two Case Reports and an Analysis of Adult Cases With Implications for Pathophysiology and Treatment

We present the first quantitative analysis of atypical teratoid rhabdoid tumors (ATRT) in adults, including two patients from our own institutions. These are of interest as one occurred during pregnancy and one is a long-term survivor. Our review of pathological findings of 50 reported cases of adult ATRT leads us to propose a solely ectodermal origin for the tumor and that epithelial-mesenchymal transition (EMT) is a defining feature. Thus, the term ATRT may be misleading. Our review of clinical findings shows that ATRT tends to originate in mid-line structures adjacent to the CSF, leading to a high rate of leptomeningeal dissemination. Thus, we hypothesize that residual undifferentiated ectoderm in the circumventricular organs, particularly the pituitary and pineal glands, is the most common origin for these tumors. We note that if growth is not arrested soon after diagnosis, or after the first relapse/progression, death is almost universal. While typically rapidly fatal (as in our first case), long-term remission is possible (as in our second). Significant predictors of prognosis were the extent of resection and the use of chemotherapy. Glial differentiation (GFAP staining) was strongly associated with leptomeningeal metastases (chi-squared p = 0.02) and both predicted markedly worse outcomes. Clinical trials including adults are rare. ATRT is primarily a disease of infancy and radiotherapy is generally avoided in those aged less than 3 years old. Treatment options in adults differ from infants in that cranio-spinal irradiation is a viable adjunct to systemic chemotherapy in the adult population. Given the grave prognosis, this combined approach appears reasonable. As effective chemotherapy is likely to cause myelosuppression, we recommend that stem-cell rescue be available locally

Incidental findings on cerebral MRI in twins: the Older Australian Twins Study

Incidental findings on structural cerebral magnetic resonance imaging (MRI) are common in healthy subjects, and the prevalence increases with age. There is a paucity of data regarding incidental cerebral findings in twins. We examined brain MRI data acquired from community-dwelling older twins to determine the prevalence and concordance of incidental cerebral findings, as well as the associated clinical implications. Participants (n = 400) were drawn from the Older Australian Twins Study. T1-weighted and T2-weighted fluid-attenuated inversion recovery (FLAIR) cerebral MRI scans were systematically reviewed by a trained, blinded clinician. Incidental findings were recorded according to pre-determined categories, and the diagnosis confirmed by an experienced neuroradiologist. Periventricular and deep white matter hyperintensities (WMH) were scored visually. WMH heritability was calculated for those with the twin pair included in the study (n = 320 individuals; monozygotic (MZ) = 92 twin pairs, dizygotic (DZ) = 68 twin pairs). Excluding infarcts and WMH, a total of 47 (11.75%) incidental abnormalities were detected. The most common findings were hyperostosis frontalis interna (8 participants; 2%), meningiomas, (6 participants; 1.5%), and intracranial lipomas (5 participants; 1.25%). Only 3% of participants were referred for follow-up. Four twin pairs, all monozygotic, had lesions concordant with their twin. Periventricular WMH was moderately heritable (0.61, CI 0.43–0.75, p = 7.21E-08) and deep WMH highly heritable (0.80, CI 0.66–0.88, p = 1.76E-13). As in the general population, incidental findings on cerebral MRI in older twins are common, although concordance rates are low. Such findings can alter the clinical outcome of participants, and should be anticipated by researchers when designing trials involving cerebral imaging

Vertebral compression fracture detection using imitation learning, patch based convolutional neural networks and majority voting

Vertebral compression fractures often go clinically undetected and consequently untreated, resulting in severe secondary fractures due to osteoporosis, and potentially leading to permanent disability or even death. Automated detection of vertebral compression fractures (VCF) could assist in routine screening and followup of incidentally scanned patients, thereby mitigating secondary fractures later. A novel fully automated method for the detection of VCF in 3D computed tomography (CT) of the chest or abdomen is presented in this work. It starts with 3D localisation of thoracic and lumbar spine regions using deep reinforcement learning (DRL) and imitation learning (IL). Six different 3D bounding boxes are generated by the localisation step, achieving an average Jaccard Index (JI)/ Dice Coefficient (DC) of 74.21%/84.71%, and detection accuracy of 97.16 % using 3 different CNN architectures. The localised region is then split into 2D sagittal slices around the coronal centre. Each slice is further divided into patches, on which convolutional neural networks (CNNs) are trained to detect VCF. Four different CNN architectures, namely 3 layered, 6 layered and transfer learning (TL) using VGG16 and ResNet50, were experimented with. The best performing architecture turned out to be the 6 layered CNN. Aggregation is performed on the VCF detection in the 2D Patches extracted from individual bounding boxes, followed by majority voting to arrive at the final decision on the status of VCF for a given patient. An average three-fold cross validation accuracy of 85.95%, sensitivity of 88.10%, specificity of 84.20% and F1 score of 85.94% were achieved on chest images using 6 layered CNN on chest images from 308 patients. An average five-fold cross validation accuracy of 86.67%, sensitivity of 88.13%, specificity of 85.02% and F1 Score of 87.04% were achieved on abdomen images from 168 patients with the 6 layered CNN

Sensitivity of a linear composite of predictor items to differential item weighting

item weights, composite predictors, equal-weighting,

Atypical Teratoid Rhabdoid Tumor: Two Case Reports and an Analysis of Adult Cases with Implications for Pathophysiology and Treatment

We present the first quantitative analysis of atypical teratoid rhabdoid tumors (ATRT) in adults, including two patients from our own institutions. These are of interest as one occurred during pregnancy and one is a long-term survivor. Our review of pathological findings of 50 reported cases of adult ATRT leads us to propose a solely ectodermal origin for the tumor and that epithelial–mesenchymal transition (EMT) is a defining feature. Thus, the term ATRT may be misleading. Our review of clinical findings shows that ATRT tends to originate in mid-line structures adjacent to the CSF, leading to a high rate of leptomeningeal dissemination. Thus, we hypothesize that residual undifferentiated ectoderm in the circumventricular organs, particularly the pituitary and pineal glands, is the most common origin for these tumors. We note that if growth is not arrested soon after diagnosis, or after the first relapse/progression, death is almost universal. While typically rapidly fatal (as in our first case), long-term remission is possible (as in our second). Significant predictors of prognosis were the extent of resection and the use of chemotherapy. Glial differentiation (GFAP staining) was strongly associated with leptomeningeal metastases (chi-squared p = 0.02) and both predicted markedly worse outcomes. Clinical trials including adults are rare. ATRT is primarily a disease of infancy and radiotherapy is generally avoided in those aged less than 3 years old. Treatment options in adults differ from infants in that cranio-spinal irradiation is a viable adjunct to systemic chemotherapy in the adult population. Given the grave prognosis, this combined approach appears reasonable. As effective chemotherapy is likely to cause myelosuppression, we recommend that stem-cell rescue be available locally

The Ecological Rationality of Simple Group Heuristics: Effects of Group Member Strategies on Decision Accuracy

The notion of ecological rationality implies that the accuracy of a decision strategy depends on features of the information environment in which it is tested. We demonstrate that the performance of a group may be strongly affected by the decision strategies used by its individual members and specify how this effect is moderated by environmental features. Specifically, in a set of simulation studies, we systematically compared four decision strategies used by the individual group members: two linear, compensatory decision strategies and two simple, noncompensatory heuristics. Individual decisions were aggregated by using a majority rule. To assess the ecological rationality of the strategies, we varied (a) the distribution of cue validities, (b) the quantity, and (c) the quality of shared information. Group performance strongly depended on the distribution of cue validities. When validities were linearly distributed, groups using a compensatory strategy achieved the highest accuracy. Conversely, when cue validities followed a J-shaped distribution, groups using a simple lexicographic heuristic performed best. While these effects were robust across different quantities of shared information, the quality of shared information exerted stronger effects on group performance. Consequences for prescriptive theories on group decision making are discussed Copyright Springer 2006compensatory and noncompensatory decision strategies, group decision making, group performance, simple heuristics,