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BACKGROUND: Scholars at home and abroad consider New Zealand rabbits to be an ideal model animal because of the similar anatomical morphology of the lumbar spine to that of the human lumbar spine. There is a lack of systematic comparison of different ways to establish rabbit intervertebral disc degeneration models under X-ray guidance. OBJECTIVE: To establish a rabbit model of lumbar disc degeneration using X-ray guided acupuncture, end-plate injection and combined method, and to compare the modeling effects of these three methods. METHODS: Eighteen 6-month-old New Zealand white rabbits were randomly selected and divided into four groups: acupuncture group, endplate injection group, combined group and blank control group. In the acupuncture group, three consecutive segments of the intervertebral discs (L2/3, L3/4, L4/5) were needled and modeled; in the endplate injection group, 50 μL of anhydrous ethanol was injected at a single point on the endplates of the three consecutive segmental discs; in the combined group, three consecutive segmental intervertebral discs were needled and injected with 50 μL of anhydrous ethanol at four azimuthal points on the endplates of the corresponding segmental discs; and the blank control group received no interventions. X-ray examination was performed to measure the disc height index at 2, 4, and 8 weeks after surgery. The intervertebral disc tissues were then taken for anatomical observation and pathological examination. RESULTS AND CONCLUSION: (1) Anatomical examination showed that fibrous annulus rupture, nucleus pulposus degeneration, and total disc structure disorder were the main manifestation in the acupuncture group, endplate injection group, and combined group, respectively. (2) X-ray examination showed that the disc height index showed the most obvious reduction in the acupuncture group at 2 weeks after operation, significant reductions in the endplate injection group at 2 and 4 weeks after operation, and significant reductions in the combined group at 2, 4, and 8 weeks after operation. (3) Pathological examination showed that the fibrous ring structure was damaged and the inner annulus fibrosus protruded inward in the acupuncture group; endplate fissure, disordered arrangement and nucleus loss were observed in the endplate injection group; total disc structure disorder with the nucleus pulposus losing water and shrinking and no obvious border with the broken annulus fibrosus was found in the combined group. To conclude, acupuncture, endplate injection and the modified endplate injection method can establish the rabbit intervertebral disc degeneration model. Compared with the single method, the modified endplate injection method can greatly accelerate and aggravate the degeneration of the intervertebral disc, and can effectively shorten the experiment period. [ABSTRACT FROM AUTHOR]

Introduction: The primary aim was to develop convolutional neural network (CNN)‐based artificial intelligence (AI) models for pneumothorax classification and segmentation for automated chest X‐ray (CXR) triaging. A secondary aim was to perform interpretability analysis on the best‐performing candidate model to determine whether the model's predictions were susceptible to bias or confounding. Method: A CANDID‐PTX dataset, that included 19,237 anonymized and manually labelled CXRs, was used for training and testing candidate models for pneumothorax classification and segmentation. Evaluation metrics for classification performance included Area under the receiver operating characteristic curve (AUC‐ROC), sensitivity and specificity, whilst segmentation performance was measured using mean Dice and true‐positive (TP)‐Dice coefficients. Interpretability analysis was performed using Grad‐CAM heatmaps. Finally, the best‐performing model was implemented for a triage simulation. Results: The best‐performing model demonstrated a sensitivity of 0.93, specificity of 0.95 and AUC‐ROC of 0.94 in identifying the presence of pneumothorax. A TP‐Dice coefficient of 0.69 is given for segmentation performance. In triage simulation, mean reporting delay for pneumothorax‐containing CXRs is reduced from 9.8 ± 2 days to 1.0 ± 0.5 days (P‐value < 0.001 at 5% significance level), with sensitivity 0.95 and specificity of 0.95 given for the classification performance. Finally, interpretability analysis demonstrated models employed logic understandable to radiologists, with negligible bias or confounding in predictions. Conclusion: AI models can automate pneumothorax detection with clinically acceptable accuracy, and potentially reduce reporting delays for urgent findings when implemented as triaging tools. [ABSTRACT FROM AUTHOR]

Objectives: To examine the utility of clinical findings, laboratory markers and X-ray radiographs (X-ray) in the assessment of children presenting with an acute non-traumatic limp. Methods: A retrospective review of all children who received hip X-rays over a 2 year period in the Children's Emergency Department, Starship Children's Hospital, Auckland, New Zealand. Children were identified from the radiology database and clinical notes reviewed. Children aged 0–12 years old were included if the limp was acute (less than 2 weeks of duration) with no history of trauma. X-rays were reported by a consultant paediatric radiologist. Univariate and multivariate analysis was performed to determine predictors of osteomyelitis and septic arthritis. Receiver operator curves were used to assess the optimum cut-off points for C reactive protein (CRP), erythrocyte sedimentation rate (ESR) and white cell count (WCC). Results: A total of 350 patients were enrolled. There were 21 (6%) abnormal X-rays . Fever, non-weight bearing, raised white cell count, raised erythrocyte sedimentation rate and raised CRP were all associated with increased risk of septic hip or osteomyelitis. The optimum inflammatory marker cut-off was a CRP of 12 with a sensitivity of 87% and specificity of 91%. Conclusion: In acute non-traumatic limp, X-rays of the hips diagnose slipped upper femoral epiphysis, as such they should be routinely used from the age of 9 years upwards. Below this age they are of little value. Inflammatory markers have utility in risk-stratifying children and selecting a group in whom to proceed with definitive tests to exclude osteomyelitis or septic hip. Children with a short history and minimal symptoms can be managed with appropriate follow up and no investigations. [ABSTRACT FROM AUTHOR]

The New Zealand School Dental Service provides dental care for children 2½-13 yr of age, without using routine diagnostic radiographs. This study investigated the pattern of dental X-ray exposure in groups of New Zealand children. One group consisted of 100 children who had all treatment before the age of 13 years with the School Dental Service. The other group consisted of 82 children who were treated in the University of Otago School of Dentistry paedodontic programme. Children in both groups turned 13 years of age between 1977 and 1982. From age 13 years these children were cared for by contracting dentists. Radiographic histories were recorded from School of Dentistry charts, and from the area Principal Dental Officer. Cumulative radiation doses were calculated. Surfaces restored at age 13 were noted from Department of Health records. Results show that by age 13 children enrolled in the School of Dentistry paedodontic programme received a mean cumulative skin dose of 23.03 mSv. Thyroid dose was 0.242 mSv. Children treated in the School Dental Service received a mean cumulative skin dose of 1.01 mSv and a thyroid dose of 0.006 mSv. Cumulative radiation dose for both groups was low. There was no significant difference in the mean number of restorations placed at age 13 years despite an extremely low level of diagnostic radiography in the School Dental Service group. [ABSTRACT FROM AUTHOR]