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Your search keyword '"Yunn-Jy Chen"' showing total 2 results
Start Over Author "Yunn-Jy Chen" Publisher biomed central
2 results on '"Yunn-Jy Chen"'

1. Comparison of measurements of mandible growth using cone beam computed tomography and its synthesized cephalograms

Author

Yunn-Jy Chen, Mu-Hsiung Chen, Jia-Da Li, Tung-Wu Lu, Cheng-Chung Lin, and Hsien-Shu Lin

Subjects
Cone beam computed tomography, Swine, Radiography, Biomedical Engineering, Dentistry, Mandible, Mandible growth, Annual growth %, Biomaterials, Bone model, Imaging, Three-Dimensional, Image Processing, Computer-Assisted, Animals, Radiology, Nuclear Medicine and imaging, Mathematics, Radiological and Ultrasound Technology, business.industry, Research, Treatment process, CBCT, General Medicine, Gold standard (test), Cone-Beam Computed Tomography, Models, Theoretical, Cephalograms, Miniature pigs, Radiographic Image Enhancement, Models, Animal, Swine, Miniature, business, Cephalogram
Abstract

Background The current study aimed to compare the measurements of the mandible morphology using 3D cone beam computed tomography (CBCT) images with those using 2D CBCT-synthesized cephalograms; to quantify errors in measurements based on 2D synthesized cephalograms; and to clarify the effects such errors have on the description of the mandibular growth. Methods Mandibles of six miniature pigs were scanned monthly using CBCT over 12 months and the data were used to reconstruct the 3D bone models. Five anatomical landmarks were identified on each bone model, and the inter-marker distances and monthly distance changes were calculated and taken as the gold standard. Synthetic 2D cephalograms were also generated for each bone model using a digitally reconstructed radiography (DRR)-generation method. Errors in cephalogram measurements were determined as the differences between the calculated variables in cephalograms and the gold standard. The variations between cephalograms and the gold standard were also compared using paired t-tests. Results While the inter-marker distance increases varied among the marker pairs, all marker pairs increased their inter-marker distances gradually every month, reaching 50% of the total annual increases during the fourth and fifth months, and then slowing down in the subsequent months. The 2D measurements significantly underestimated most of the inter-marker distances throughout the monitoring period, in most of the monthly inter-marker distance changes during the first four months, and in the total growth (p

Published
2014

2. Test-retest reliability of mandibular morphology measurements on cone-beam computed tomography-synthesized cephalograms with random head positioning errors.

Author

Hsien-Shu Lin, Yunn-Jy Chen, Hsuan-Lun Lu, Tung-Wu Lu, Chien-Chih Chen, Lin, Hsien-Shu, Chen, Yunn-Jy, Lu, Hsuan-Lun, Lu, Tung-Wu, and Chen, Chien-Chih

Subjects
*MANDIBLE, *CONE beam computed tomography, *CEPHALOMETRY, *RADIOGRAPHY, *BIOMEDICAL engineering, *COMPUTED tomography, *HEAD, *DIGITAL image processing, *MEDICAL errors, *ANATOMY, RESEARCH evaluation
Abstract

Background: Cephalometric radiography has been used for orthodontic and surgical treatment planning and assessment, and for quantifying mandibular growth. However, it remains unclear how head positioning errors and the level of examiner experience affect the reliability of such morphometric measurements. The current study aimed to bridge the gap by determining the intra-, inter-rater, and inter-session reliability of measurements of mandibular morphology with random head positioning errors as measured by a junior and a senior dentist.Methods: Cone-beam computed tomography data of twelve mandibles were obtained with each rotated randomly away from the neutral position within the range of +3 and -3° along each of the anatomical axes to simulate six imaging trials. A synthetic cephalogram for each trial was obtained via a digitally reconstructed radiography (DRR) technique and eleven landmarks for twelve morphological parameters on the cephalogram were identified manually six times by a junior and a senior dentist. The procedure was repeated on another day within 5 days. Test-retest reliability was assessed in terms of an intra-class correlation coefficient (ICC) using a two-way mixed-effects model.Results: Good to very good intra-rater (senior: ICC > 0.92; junior: ICC > 0.78), inter-rater (ICC > 0.70 for most parameters) and inter-session reliability (senior: ICC > 0.84; junior: ICC > 0.62) were found. Bland & Altman plots of inter-rater comparisons show that there were systematical biases between the examiners on most parameters, except for the distance between Gonion and Pogonion.Conclusions: The current results suggest that good to very good intra-rater, inter-rater and inter-session reliability can be achieved for most parameters with randomized head positioning errors; higher inter-session reliability can be achieved by more experienced examiners; and that long-term monitoring of mandibular growth based on cephalographic measurements should be made by the same more experienced examiner. The current DRR-based approach can be used to evaluate individual factors that affect the morphological measurements. [ABSTRACT FROM AUTHOR]

Published
2017
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