Quantitative evaluation of an automatic segmentation method for 3D reconstruction of intervertebral scoliotic disks from MR images

Background: For some scoliotic patients the spinal instrumentation is inevitable. Among these patients, those with stiff curvature will need thoracoscopic disk resection. The removal of the intervertebral disk with only thoracoscopic images is a tedious and challenging task for the surgeon. With computer aided surgery and 3D visualisation of the interverterbral disk during surgery, surgeons will have access to additional information such as the remaining disk tissue or the distance of surgical tools from critical anatomical structures like the aorta or spinal canal. We hypothesized that automatically extracting 3D information of the intervertebral disk from MR images would aid the surgeons to evaluate the remaining disk and would add a security factor to the patient during thoracoscopic disk resection.Methods: This paper presents a quantitative evaluation of an automatic segmentation method for 3D reconstruction of intervertebral scoliotic disks from MR images. The automatic segmentation method is based on the watershed technique and morphological operators. The 3D Dice Similarity Coefficient (DSC) is the main statistical metric used to validate the automatically detected preoperative disk volumes. The automatic detections of intervertebral disks of real clinical MR images are compared to manual segmentation done by clinicians.Results: Results show that depending on the type of MR acquisition sequence, the 3D DSC can be as high as 0.79 (+/- 0.04). These 3D results are also supported by a 2D quantitative evaluation as well as by robustness and variability evaluations. The mean discrepancy (in 2D) between the manual and automatic segmentations for regions around the spinal canal is of 1.8 (+/- 0.8) mm. The robustness study shows that among the five factors evaluated, only the type of MRI acquisition sequence can affect the segmentation results. Finally, the variability of the automatic segmentation method is lower than the variability associated with manual segmentation performed by different physicians.Conclusions: This comprehensive evaluation of the automatic segmentation and 3D reconstruction of intervertebral disks shows that the proposed technique used with specific MRI acquisition protocol can detect intervertebral disk of scoliotic patient. The newly developed technique is promising for clinical context and can eventually help surgeons during thoracoscopic intervertebral disk resection

When COVID-19 met families living in armed-conflict zones: the importance of maternal trauma and child self-regulation

The COVID-19 outbreak began in Israel at the end of February 2020, and on March 17, 2020, a general lockdown was announced. Families were instructed to stay at home and schools and non-essential businesses were closed. Aiming to understand how families who were already living in areas of high exposure to armed conflict would be affected by another external stressful condition, data were collected before and after the outbreak. Mothers and children (aged 10–45 months) were recruited from areas with high (n = 40) and low (n = 78) exposure to armed conflict. Mothers reported on their posttraumatic stress symptoms (PTSS) and on their child's effortful control tendencies prior to the outbreak. Toward the end of the first lockdown, mothers were interviewed regarding adverse effects of the outbreak on their family. No group differences were found for maternal perceptions of adverse effects of COVID-19. However, a moderation model was revealed, indicating that maternal PTSS as well as child effortful control predicted adverse effects of COVID-19 only in the high-exposure group. Results are discussed considering cumulative stress and risk factors

Syncopation creates the sensation of groove in synthesized music examples

In order to better understand the musical properties which elicit an increased sensation of wanting to move when listening to music groove we investigate the effect of adding syncopation to simple piano melodies, under the hypothesis that syncopation is correlated to groove. Across two experiments we examine listeners' experience of groove to synthesized musical stimuli covering a range of syncopation levels and densities of musical events, according to formal rules implemented by a computer algorithm that shifts musical events from strong to weak metrical positions. Results indicate that moderate levels of syncopation lead to significantly higher groove ratings than melodies without any syncopation or with maximum possible syncopation. A comparison between the various transformations and the way they were rated shows that there is no simple relation between syncopation magnitude and groove

Langerhans Cell Histiocytosis With Vertebral Involvement Diagnosed and Treated Over the Last 15 Years in a Single Canadian Pediatric Academic Institution.

We report 11 children with vertebral lesion of Langerhans cell histiocytosis (LCH) diagnosed and treated between 2000 and 2015. Vertebral lesions were usually present at LCH diagnosis. No child developed neurological symptoms. Among 29 vertebral lesions, only 2 were unstable. Chemotherapy was used in all children but 3. A LCH recurrence was observed in 6 patients, involving vertebrae in 4 cases. All children were disease-free at their last follow-up. Sequelae were more often radiologic than clinical. Since potential recurrences and incomplete bone regeneration exist, discussion about optimal treatment and long-term follow-up of vertebral lesions are essential

The role of children in the spread of COVID-19: Using household data from Bnei Brak, Israel, to estimate the relative susceptibility and infectivity of children.

One of the significant unanswered questions about COVID-19 epidemiology relates to the role of children in transmission. This study uses data on infections within households in order to estimate the susceptibility and infectivity of children compared to those of adults. The data were collected from households in the city of Bnei Brak, Israel, in which all household members were tested for COVID-19 using PCR (637 households, average household size of 5.3). In addition, serological tests were performed on a subset of the individuals in the study. Inspection of the PCR data shows that children are less likely to be tested positive compared to adults (25% of children positive over all households, 44% of adults positive over all households, excluding index cases), and the chance of being positive increases with age. Analysis of joint PCR/serological data shows that there is under-detection of infections in the PCR testing, which is more substantial in children. However, the differences in detection rates are not sufficient to account for the differences in PCR positive rates in the two age groups. To estimate relative transmission parameters, we employ a discrete stochastic model of the spread of infection within a household, allowing for susceptibility and infectivity parameters to differ among children and adults. The model is fitted to the household data using a simulated maximum likelihood approach. To adjust parameter estimates for under-detection of infections in the PCR results, we employ a multiple imputation procedure using estimates of under-detection in children and adults, based on the available serological data. We estimate that the susceptibility of children (under 20 years old) is 43% (95% CI: [31%, 55%]) of the susceptibility of adults. The infectivity of children was estimated to be 63% (95% CI: [37%, 88%]) relative to that of adults