Alveolar Bone Segmentation in Intraoral Ultrasonographs with Machine Learning.

The use of intraoral ultrasound imaging has received great attention recently due to the benefits of being a portable and low-cost imaging solution for initial and continuing care that is noninvasive and free of ionizing radiation. Alveolar bone is an important structure in the periodontal apparatus to support the tooth. Accurate assessment of alveolar bone level is essential for periodontal diagnosis. However, interpretation of alveolar bone structure in ultrasound images is a challenge for clinicians. This work is aimed at automatically segmenting alveolar bone and locating the alveolar crest via a machine learning (ML) approach for intraoral ultrasound images. Three convolutional neural network-based ML methods were trained, validated, and tested with 700, 200, and 200 images, respectively. To improve the robustness of the ML algorithms, a data augmentation approach was introduced, where 2100 additional images were synthesized through vertical and horizontal shifting as well as horizontal flipping during the training process. Quantitative evaluations of 200 images, as compared with an expert clinician, showed that the best ML approach yielded an average Dice score of 85.3%, sensitivity of 88.5%, and specificity of 99.8%, and identified the alveolar crest with a mean difference of 0.20 mm and excellent reliability (intraclass correlation coefficient ≥0.98) in less than a second. This work demonstrated the potential use of ML to assist general dentists and specialists in the visualization of alveolar bone in ultrasound images.

Topical contrast agents to improve soft-tissue contrast in the upper airway using cone beam CT: a pilot study.

The purpose of this study is to explore the topical use of radiographic contrast agents to enhance soft-tissue contrast on cone beam CT (CBCT) images. Different barium sulphate concentrations were first tested using an airway phantom. Different methods of barium sulphate application (nasal drops, syringe, spray and sinus wash) were then tested on four volunteers, and nebulized iodine was tested in one volunteer. CBCT images were performed and then assessed subjectively by two examiners for contrast agent uniformity and lack of streak artefact. 25.0% barium sulphate presented adequate viscosity and radiodensity. Barium sulphate administered via nasal drops and sprays showed non-uniform collection at the nostrils, along the inferior and/or middle nasal meatuses and posterior nasal choana. The syringe and sinus wash showed similar results with larger volumes collecting in the naso-oropharynx. Nebulized iodine failed to distribute into the nasal cavity and scarcely collected at the nostrils. All methods of nasal application failed to adequately reach or uniformly coat the nasal cavity beyond the inferior nasal meatuses. The key factors to consider for optimum topical radiographic contrast in the nasal airway are particle size, flow velocity and radio-opacity.

An in vitro study on the deposition of micrometer-sized particles in the extrathoracic airways of adults during tidal oral breathing.

Deposition of particles in the aerodynamic diameter range of 0.5-6.7 µm was measured in nine replicas of the extrathoracic airways of adults with four sinusoidal patterns and oral breathing. The four chosen breathing patterns are typical of those occurring during natural resting breathing and during nebulization therapy. Additionally, deposition of micrometer-sized particles in the "Alberta Idealized Adult Throat," which was previously found useful in simulating the average deposition of particles during inhalation of constant flow rates, was measured during inhalation of the four sinusoidal patterns in this study. To reduce intersubject scatter in developing predictive correlations, the non-dimensional Reynolds (Re) and Stokes (Stk) numbers are used with the square root of the average cross sectional area of the oral airways as the characteristic diameter being found to reduce intersubject variability to the highest extent. Our best fit to the deposition data is given by η = [1 - 1/(1.51 x 10(5)(Stk(3.03)Re(0.25)) + 1)] x 100. Moreover, the "Alberta Idealized Adult Throat" is found to mimic average deposition, given in past in vivo studies, in the upper airways of adults during natural tidal breathing.

Morphinome--proteome of the nervous system after morphine treatment.

Proteome is a natural consequence of the post-genome era when the HUGO project (Human Genome Organization) has almost been completed. Here, a specifically aimed proteome in drug dependence--morphinome, is described, including tasks, strategies and pitfalls of the methodology.

Gene expressions of ubiquitin and hsp70 following focal ischaemia in rat brain.

Expression of genes coding for ubiquitin and heatshock protein (hsp) 70 were examined by in situ hybridization using a rat model with permanent occlusion of the distal middle cerebral artery (MCA). Only polyubiquitin (UbC) mRNA increased markedly following ischaemia in the central zone of the MCA territory of the neocortex. UbC gene expression reached the maximum level 4 h post-occlusion and remained elevated at 24 h. UbC expression was retarded slightly compared with that of the hsp70 gene. UbB and Ub-S30 were expressed at almost similar levels in both the ischaemic and non-ischaemic hemispheres. These results indicated that UbC probably has the most stress-inducible characteristics among the three ubiquitin genes.

Ubiquitin gene expression following transient forebrain ischemia.

Ubiquitin gene expression following transient forebrain ischemia in the rat was analyzed by three probes which were specific for UbC, UbB and UbS30 mRNA. According to the in situ hybridization studies, each type of ubiquitin gene expression decreased at 30 min of reperfusion following 20 min of forebrain ischemia, thereafter increased, and then reached a peak at 4-6 h, both in the cortex and hippocampus. These changes returned to the control level after 24-48 h of recirculation. Among the three ubiquitin transcripts, changes in UbC expression were more marked in the hippocampus, and persistent expression of UbC transcripts in the CA1 and CA3 regions was observed at 24 h of reperfusion. With dot-blot analysis, significant increases in the UbC transcripts were noted at 4 h of reperfusion in the hippocampus, and at 6 h in the cortex following 20 min of ischemia. These results suggest that changes in UbC expression might be a good indicator of ischemic stress.

Nucleotide sequence and expression of the rat polyubiquitin mRNA.

Two polyubiquitin clones have been isolated from a rat brain cDNA library. Clone 22B1 contained four repetitive ubiquitin in tandem. Clone 19A2 coded ten complete repetitive ubiquitin followed by the first 20 amino acids of the previous repetitive ubiquitin and a distinct peptide. These clones were rat homologues for human UbB and UbC gene families, respectively. 1.2 kb UbB transcript, as well as 2.8 kb and 3.2 kb UbC transcripts, were widely expressed in the various rat tissues.