Etiological classification of seizures in pediatric age group (6-12years) – MRI study

Background: A seizure is an occurrence of signs or symptoms due to abnormal excessive orsynchronous neuronal activity in the brain. The present study aims to study the etiological factorsand clinical profile for new-onset seizures in children aged 6-12 years and to determine thefrequency of Magnetic resonance imaging (MRI) abnormalities in the pediatrics age group with new-onset unprovoked seizure and those with inadequately investigated longstanding epilepsy andclassify the etiology based on the MRI findings. Methods: A prospective study involving a total of 50patients was recruited aged between 6 to 12 years. All of them underwent neuro-imaging with MRI.Uncooperative patients were imaged following sedation and monitoring by the anesthetist. Allchildren aged 6-12 years who presented with new-onset seizures were included. All MR images wereobtained at a 3-mm section thickness except magnetization-prepared rapid gradient-echo images,which are obtained at a 1.8-mm section thickness. Results: Of the 50 patients 28 presented withgeneralized tonic-clonic seizures, 12 with simple partial seizures, 10 with complex partial seizures.Generalized seizures were a more common presentation than partial seizures in children 6-12 yearsof age. Conclusion: With the positivity of the MRI in the new-onset seizure in children between 6-12 years in our study gives an important aspect of the essential factor of imaging in pediatric new-onset seizures.

Is it possible to estimate volume of bone defects formed on dry sheep mandibles more practically by secondarily reconstructing section thickness of cone beam computed tomography images?

Objectives: The purpose of this study was to evaluate the effect of section thickness on volume estimations of bone defects scanned using cone beam computed tomography (CBCT). Methods: 25 bone defects were prepared on sheep mandibles and scanned using a KaVo 3D eXam (KaVo Dental, Biberach, Germany) CBCT device. Section thickness of images were reconstructed at 0.25, 0.5, and 0.75 mm to estimate the volume of these defects using the semiautomatic segmentation method. The volume averages obtained using microcomputed tomography and Archimedes’ method served as reference values. The estimated volumes at each section thickness were compared with the actual volumes using the Friedman test. The accuracy of volume estimation was determined by the percentage error with respect to the reference values, and the mean absolute error (MAE) was calculated. Results: Volumetric values of bone defects obtained with CBCT at section thicknesses up to 0.5 mm were compatible with the actual volumes (p > 0.05). The percentage errors at section thicknesses of 0.25, 0.5, and 0.75 mm were −5.4%, −7.3%, and −13.1%, respectively. The mean absolute errors were 13.6 mm3, 15.7 mm3, and 18.2 mm3, respectively. Conclusions: The section thickness values of CBCT images can be increased to a reasonable level to obtain accurate volume estimation results and save time. The semiautomatic segmentation method can be used reliably for volume estimations of bone defects.

The Influence of Cross-Section Thickness on Diameter at Breast Height Estimation from Point Cloud

Circle-fitting methods are commonly used to estimate diameter at breast height (DBH) of trees from horizontal cross-section of point clouds. In this paper, we addressed the problem of cross-section thickness optimization regarding DBH estimation bias and accuracy. DBH of 121 European beeches (Fagus sylvatica L.) and 43 Sessile oaks (Quercus petraea (Matt.) Liebl.) was estimated from cross-sections with thicknesses ranging from 1 to 100 cm. The impact of cross-section thickness on the bias, standard error, and accuracy of DBH estimation was statistically significant. However, the biases, standard errors, and accuracies of DBH estimation were not significantly different among 1–10-cm cross-sections, except for oak DBH estimation accuracy from an 8-cm cross-section. DBH estimations from 10–100-cm cross-sections were considerably different. These results provide insight to the influence of cross-section thickness on DBH estimation by circle-fitting methods, which is beneficial for point cloud data acquisition planning and processing. The optimal setting of cross-section thickness facilitates point cloud processing and DBH estimation by circle-fitting algorithms.