Postural orientation and equilibrium processes associated with increased postural sway in autism spectrum disorder (ASD)

Background: Increased postural sway has been repeatedly documented in children with autism spectrum disorder (ASD). Characterizing the control processes underlying this deficit, including postural orientation and equilibrium, may provide key insights into neurophysiological mechanisms associated with ASD. Postural orientation refers to children’s ability to actively align their trunk and head with respect to their base of support, while postural equilibrium is an active process whereby children coordinate ankle dorsi-/plantar-flexion and hip abduction/adduction movements to stabilize their upper body. Dynamic engagement of each of these control processes is important for maintaining postural stability, though neither postural orientation nor equilibrium has been studied in ASD. Methods: Twenty-two children with ASD and 21 age and performance IQ-matched typically developing (TD) controls completed three standing tests. During static stance, participants were instructed to stand as still as possible. During dynamic stances, participants swayed at a comfortable speed and magnitude in either anterior-posterior (AP) or mediolateral (ML) directions. The center of pressure (COP) standard deviation and trajectory length were examined to determine if children with ASD showed increased postural sway. Postural orientation was assessed using a novel virtual time-to-contact (VTC) approach that characterized spatiotemporal dimensions of children’s postural sway (i.e., body alignment) relative to their postural limitation boundary, defined as the maximum extent to which each child could sway in each direction. Postural equilibrium was quantified by evaluating the amount of shared or mutual information of COP time series measured along the AP and ML directions. Results: Consistent with prior studies, children with ASD showed increased postural sway during both static and dynamic stances relative to TD children. In regard to postural orientation processes, children with ASD demonstrated reduced spatial perception of their postural limitation boundary towards target directions and reduced time to correct this error during dynamic postural sways but not during static stance. Regarding postural equilibrium, they showed a compromised ability to decouple ankle dorsi-/plantar-flexion and hip abduction/adduction processes during dynamic stances. Conclusions: These results suggest that deficits in both postural orientation and equilibrium processes contribute to reduced postural stability in ASD. Specifically, increased postural sway in ASD appears to reflect patients’ impaired perception of their body movement relative to their own postural limitation boundary as well as a reduced ability to decouple distinct ankle and hip movements to align their body during standing. Our findings that deficits in postural orientation and equilibrium are more pronounced during dynamic compared to static stances suggests that the increased demands of everyday activities in which children must dynamically shift their COP involve more severe postural control deficits in ASD relative to static stance conditions that often are studied. Systematic assessment of dynamic postural control processes in ASD may provide important insights into new treatment targets and neurodevelopmental mechanisms

Longitudinal composite 3D faces and facial growth trends in children 6–11 years of age using 3D cephalometric surface imaging

Background Normative craniofacial anthropometry provides clinically important reference values used in the treatment of craniofacial conditions. Few objective datasets of normative data exist for children. Aim To establish normative data regarding craniofacial morphology changes with growth in children. Subjects and methods 3D surface images of the same group of healthy children aged 6 − 11 years old recruited from a Dallas school were taken annually between the years 2015 − 2020. Composite 3D cephalometric faces were created for boys and girls of each age. General and craniofacial anthropometric measurements were compared. Results Seven hundred ninety one individual stereophotogrammetric acquisitions were used (400 boys, 391 girls) taken from 180 children. Linear facial, orbital, nasal, and oral anthropometric measurements revealed a consistent increase in magnitude with age. Composite 3D face comparisons revealed prominent vertical and anteroposterior growth trends in the lower and upper facial regions. Conclusion This study presents a longitudinal 3D control dataset of the same group of children over a 6-year period that can serve as reference norms for facial growth values and trends in children aged 6–11 years. The composite 3D normative faces are available for clinical and research purposes upon request, which may be interrogated and measured according to user need and preference

A noninvasive tumor oxygenation imaging strategy using magnetic resonance imaging of endogenous blood and tissue water

Purpose: To present a novel imaging strategy for noninvasive measurement of tumor oxygenation using MR imaging of endogenous blood and tissue water. Theory and Methods: The proposed approach for oxygen partial pressure (pO 2 ) estimation is based on intravoxel incoherent motion diffusion MRI and the dependence of the blood R 2 relaxation rate on the inter-echo spacing measured using a multiple spin-echo Carr-Purcell-Meiboom-Gill sequence and weak-field diffusion model. The accuracy of the approach was validated by comparison with 19 F MRI oximetry. Results: The results in eight rats at 4.7 T showed that tumors have longer T 1 (1980 6 186 ms) and T 2 (59 6 9 ms) relaxation times, heterogeneous blood volume fraction (0.23 6

Viable and necrotic tumor assessment from whole slide images of osteosarcoma using machine-learning and deep-learning models.

Pathological estimation of tumor necrosis after chemotherapy is essential for patients with osteosarcoma. This study reports the first fully automated tool to assess viable and necrotic tumor in osteosarcoma, employing advances in histopathology digitization and automated learning. We selected 40 digitized whole slide images representing the heterogeneity of osteosarcoma and chemotherapy response. With the goal of labeling the diverse regions of the digitized tissue into viable tumor, necrotic tumor, and non-tumor, we trained 13 machine-learning models and selected the top performing one (a Support Vector Machine) based on reported accuracy. We also developed a deep-learning architecture and trained it on the same data set. We computed the receiver-operator characteristic for discrimination of non-tumor from tumor followed by conditional discrimination of necrotic from viable tumor and found our models performing exceptionally well. We then used the trained models to identify regions of interest on image-tiles generated from test whole slide images. The classification output is visualized as a tumor-prediction map, displaying the extent of viable and necrotic tumor in the slide image. Thus, we lay the foundation for a complete tumor assessment pipeline from original histology images to tumor-prediction map generation. The proposed pipeline can also be adopted for other types of tumor

Comparative Volume Analysis of Alveolar Defects by 3D Simulation

A precise volumetric assessment of maxillary alveolar defects in patients with cleft lip and palate can reduce donor site morbidity or allow accurate preparation of bone substitutes in future applications. However, there is a lack of agreement regarding the optimal volumetric technique to adopt. This study measured the alveolar bone defects by using two cone-beam computed tomography (CBCT)-based surgical simulation methods. Presurgical CBCT scans from 32 patients with unilateral or bilateral clefts undergoing alveolar bone graft surgery were analyzed. Two hands-on CBCT-based volumetric measurement methods were compared: the 3D real-scale printed model-based surgical method and the virtual surgical method. Different densities of CBCT were compared. Intra- and inter-examiner reliability was assessed. For patients with unilateral clefts, the average alveolar defect volumes were 1.09 ± 0.24 and 1.09 ± 0.25 mL (p > 0.05) for 3D printing- and virtual-based models, respectively; for patients with bilateral clefts, they were 2.05 ± 0.22 and 2.02 ± 0.27 mL (p > 0.05), respectively. Bland–Altman analysis revealed that the methods were equivalent for unilateral and bilateral alveolar cleft defect assessment. No significant differences or linear relationships were observed between adjacent different densities of CBCT for model production to obtain the measured volumes. Intra- and inter-examiner reliability was moderate to good (intraclass correlation coefficient (ICC) > 0.6) for all measurements. This study revealed that the volume of unilateral and bilateral alveolar cleft defects can be equally quantified by 3D-printed and virtual surgical simulation methods and provides alveolar defect-specific volumes which can serve as a reference for planning and execution of alveolar bone graft surgery

Dual ¹⁹F/¹H MR Gene Reporter Molecules for <i>in Vivo</i> Detection of β-Galactosidase

Increased emphasis on personalized medicine and novel therapies requires the development of noninvasive strategies for assessing biochemistry <i>in vivo</i>. The detection of enzyme activity and gene expression <i>in vivo</i> is potentially important for the characterization of diseases and gene therapy. Magnetic resonance imaging (MRI) is a particularly promising tool, since it is noninvasive and has no associated radioactivity, yet penetrates deep tissue. We now demonstrate a novel class of dual ¹H/¹⁹F nuclear magnetic resonance (NMR) <i>lacZ</i> gene reporter molecule to specifically reveal enzyme activity in human tumor xenografts growing in mice. We report the design, synthesis, and characterization of six novel molecules and evaluation of the most effective reporter in mice <i>in vivo</i>. Substrates show a single ¹⁹F NMR signal and exposure to β-galactosidase induces a large ¹⁹F NMR chemical shift response. In the presence of ferric ions, the liberated aglycone generates intense proton MRI T₂ contrast. The dual modality approach allows both the detection of substrate and the imaging of product enhancing the confidence in enzyme detection