• The Journal of the Korean dental association
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• v.56 no.10
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• pp.538-547
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• 2018

ITK-SNAP (http://www.itksnap.org) and 3D Slicer (CMFreg extension module; www.slicer.org) are open-source softwares which can be used for superimposition of cone-beam CT images. For superimposition, segmentation of bone is done with ITK-SNAP, and then voxel based superimposition of CBCT images can be performed using 3D Slicer. 3D Slicer has various visualization modules which are not provided in common commercial programs. 'Models' module is used to visualize two overlapping three-dimensional images, and this allows various visualizations by changing view mode and color of the model. In addition, differences between two CBCT images can be represented in a color map using 'ShapePopulationViewer' module. This report introduces how to superimpose and visualize CBCT images using ITK-SNAP and 3D Slicer, and the usefulness and limitations of both softwares will be discussed in comparison with commercial softwares.

• Archives of Craniofacial Surgery
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• v.20 no.6
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• pp.361-369
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• 2019

Background: Trauma is one of the most common causes of enophthalmos, and post-traumatic enophthalmos primarily results from an increased volume of the bony orbit. We achieved good long-term results by simultaneously using an anatomical absorbable implant and iliac bone graft to correct post-traumatic enophthalmos. Methods: From January 2012 to December 2016, we performed operations on seven patients with post-traumatic enophthalmos. In all seven cases, reduction surgery for the initial trauma was performed at our hospital. Hertel exophthalmometry, clinical photography, three-dimensional computed tomography (3D-CT), and orbital volume measurements using software to calculate the specific volume captured on 3D-CT (ITK-SNAP, Insight Toolkit-SNAP) were performed preoperatively and postoperatively. Results: Patients were evaluated based on exophthalmometry, clinical photographs, 3D-CT, and orbital volume measured by the ITK-SNAP program at 5 days and 1 year postoperatively, and all factors improved significantly compared with the preoperative baseline. Complications such as hematoma or extraocular muscle limitation were absent, and the corrected orbital volume was well maintained at the 1-year follow-up visit. Conclusion: We present a method to correct enophthalmos by reconstructing the orbital wall using an anatomical absorbable implant and a simultaneous autologous iliac bone graft. All cases showed satisfactory results for enophthalmos correction. We suggest this method as a good option for the correction of post-traumatic enophthalmos.

• Imaging Science in Dentistry
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• v.52 no.4
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• pp.399-408
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• 2022

Purpose: The purpose of this study was to compare volume measurements obtained using 2 image software packages on Digital Imaging and Communications in Medicine (DICOM) images acquired from 1 multidetector computed tomography and 5 cone-beam computed tomography devices, using different protocols for physical volume measurements. Materials and Methods: Four pieces of bovine leg were prepared. Marrow was removed from 3 pieces, leaving cortical bone exposed. The resulting space of 1 piece was filled with water, another was filled with propylene glycol, and the third was left unfilled. The marrow in the fourth sample was left fully intact. Volume measurements were obtained after importing DICOM images into the Dolphin Imaging 11.95 and ITK-SNAP software programs. Data were analyzed using 3-way analysis of variance with a generalized linear model to determine the effects of voxel size, software, and content on percentage mean volume differences between tomographic protocols. A significance level of 0.05 was used. Results: The intraclass correlation coefficients for intraobserver and interobserver reliability were, respectively, 0.915 and 0.764 for the Dolphin software and 0.894 and 0.766 for the ITK-SNAP software. Three sources of statistically significant variation were identified: the interaction between software and content (P=0.001), the main effect of content (P=0.014), and the main effect of software (P=0.001). Voxel size was not associated with statistically significant differences in volume measurements. Conclusion: Both content and software influenced the accuracy of volume measurements, especially when the content had gray values similar to those of the adjacent tissues.

• Korean Journal of Computational Design and Engineering
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• v.17 no.6
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• pp.436-442
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• 2012

Traumatic loading during car accidents or sports activities can lead to cervical spinal cord injury. Experiments in spinal cord injury research are mainly carried out on rabbit or rat. Finite element models that include the rat cervical spinal cord and adjacent soft tissues should be developed for efficient studies of mechanisms of spinal cord injury. Images of a rat were obtained from high resolution MRI scanner. Polygonal surfaces were extracted structure by structure from the MRI data using the ITK-SNAP volume segmentation software. These surfaces were converted to Non-uniform Rational B-spline surfaces by the INUS Rapidform rapid prototyping software. Rapidform was also used to generate a thin shell surface model for the dura mater which sheathes the spinal cord. Altair's Hypermesh pre-processor was used to generate finite element meshes for each structure. These processes in this study can be utilized in modeling of other biomedical tissues and can be one of examples for reverse engineering on biomechanics.

• Imaging Science in Dentistry
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• v.43 no.3
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• pp.163-169
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• 2013

Purpose: Tonsilloliths are calcifications found in the crypts of the palatal tonsils and can be detected on routine panoramic examinations. This study was performed to highlight the benefits of cone-beam computed tomography (CBCT) in the diagnosis of tonsilloliths appearing bilaterally on panoramic radiographs. Materials and Methods: The sample group consisted of 7 patients who had bilateral radiopaque lesions at the area of the ascending ramus on panoramic radiographs. CBCT images for every patient were obtained from both sides of the jaw to determine the exact locations of the lesions and to rule out other calcifications. The calcifications were evaluated on the CBCT images using Ez3D2009 software. Additionally, the obtained images in DICOM format were transferred to ITK SNAP 2.4.0 pc software for semiautomatic segmentation. Segmentation was performed using contrast differences between the soft tissues and calcifications on grayscale images, and the volume in mm3 of the segmented three dimensional models were obtained. Results: CBCT scans revealed that what appeared on panoramic radiographs as bilateral images were in fact unilateral lesions in 2 cases. The total volume of the calcifications ranged from 7.92 to $302.5mm^3$. The patients with bilaterally multiple and large calcifications were found to be symptomatic. Conclusion: The cases provided the evidence that tonsilloliths should be considered in the differential diagnosis of radiopaque masses involving the mandibular ramus, and they highlight the need for a CBCT scan to differentiate pseudo- or ghost images from true bilateral pathologies.

• Imaging Science in Dentistry
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• v.45 no.1
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• pp.1-5
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• 2015

Purpose: Lateral pterygoid muscle (LPM) plays an important role in jaw movement and has been implicated in Temporomandibular disorders (TMDs). Migraine has been described as a common symptom in patients with TMDs and may be related to muscle hyperactivity. This study aimed to compare LPM volume in individuals with and without migraine, using segmentation of the LPM in magnetic resonance (MR) imaging of the TMJ. Materials and Methods: Twenty patients with migraine and 20 volunteers without migraine underwent a clinical examination of the TMJ, according to the Research Diagnostic Criteria for TMDs. MR imaging was performed and the LPM was segmented using the ITK-SNAP 1.4.1 software, which calculates the volume of each segmented structure in voxels per cubic millimeter. The chi-squared test and the Fisher's exact test were used to relate the TMD variables obtained from the MR images and clinical examinations to the presence of migraine. Logistic binary regression was used to determine the importance of each factor for predicting the presence of a migraine headache. Results: Patients with TMDs and migraine tended to have hypertrophy of the LPM (58.7%). In addition, abnormal mandibular movements (61.2%) and disc displacement (70.0%) were found to be the most common signs in patients with TMDs and migraine. Conclusion: In patients with TMDs and simultaneous migraine, the LPM tends to be hypertrophic. LPM segmentation on MR imaging may be an alternative method to study this muscle in such patients because the hypertrophic LPM is not always palpable.

• The korean journal of orthodontics
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• v.50 no.2
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• pp.86-97
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• 2020

Objective: To propose a three-dimensional (3D) method for evaluating temporomandibular joint (TMJ) changes during Twin-block treatment. Methods: Seventeen patients with Class II division 1 malocclusion treated using Twin-block and nine untreated patients with a similar malocclusion were included in this research. We collected their cone beam computed tomography (CBCT) data from before and 8 months after treatment. Segmentations were constructed using ITK-SNAP. Condylar volume and superficial area were measured using 3D Slicer. The 3D landmarks were identified on CBCT images by using Dolphin software to assess the condylar positional relationship. 3D models of the mandible and glenoid fossa of the patients were constructed and registered via voxel-based superimposition using 3D Slicer. Thereafter, skeletal changes could be visualized using 3DMeshMetric in any direction of the superimposition on a color-coded map. All the superimpositions were measured using the same scale on the distance color-coded map, in which red color represents overgrowth and blue color represents resorption. Results: Significant differences were observed in condylar volume, superficial area, and condylar position in both groups after 8 months. Compared with the control group (CG), the Twin-block group exhibited more obvious condyle-fossa modifications and joint positional changes. Moreover, on the color-coded map, more obvious condyle-fossa modifications could be observed in the posterior and superior directions in the Twin-block group than in the CG. Conclusions: We successfully established a 3D method for measuring and evaluating TMJ changes caused by Twin-block treatment. The treatment produced a larger condylar size and caused condylar positional changes.

• Imaging Science in Dentistry
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• v.52 no.1
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• pp.103-108
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• 2022

Purpose: Disc displacement can cause resorption of the head of the condyle and affect its volume. This study analysed the volume of normal condyles and those with disc displacement with reduction (DDR) in cone-beam computed tomography (CBCT) scans from the Indonesian population. Materials and Methods: This study analysed 56 condyles (26 normal and 30 with DDR) from patients who visited the Oral and Maxillofacial Radiology Unit after being referred from the Prosthodontics Unit at Dental Hospital Universitas Padjadjaran from December 2020 to February 2021. Samples were divided into 2 groups (normal and DDR left and right-side condyles) based on the DC/TMD Axis 1 form through the clinical examination results. Both sample groups were exposed to CBCT radiation. The CBCT imaging results in the Digital Imaging and Communications in Medicine format were exported to the open-source ITK-SNAP format to determine condyle volume. Volumetric data from the cortical and trabecular areas of the right or left side condyles were arranged by sex. The independent t-test was used to determine the significance of differences with IBM SPSS version 21.0. Intra- and inter-observer reliability and validity were tested before determining the volume of the condyles. Results: Normal condyles and DDR condyles showed significant differences in volume (P<0.05). Significant differences were also seen in cortical (P=0.0007) and trabecular (P=0.0045) volumes. There was a significant difference in condylar volume based on sex. Conclusion: The normal condyle volume was significantly different from the DDR condyle volume in both sexes.

• Imaging Science in Dentistry
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• v.53 no.3
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• pp.221-227
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• 2023

Purpose: This study was performed to develop a linear regression model using the pulp-to-tooth volume ratio (PTVR) ratio of the maxillary canine, assessed through cone-beam computed tomography (CBCT) images, to predict chronological age (CA) in Indonesian adults. Materials and Methods: A sample of 99 maxillary canines was collected from patients between 20 and 49.99 years old. These samples were obtained from CBCT scans taken at the Universitas Padjadjaran Dental Hospital in Indonesia between 2018 and 2022. Pulp volume (PV) and tooth volume (TV) were measured using ITK-SNAP, while PTVR was calculated from the PV/TV ratio. Using RStudio, a linear regression was performed to predict CA using PTVR. Additionally, correlation and observer agreement were assessed. Results: The PTVR method demonstrated excellent reproducibility, and a significant correlation was found between the PTVR of the maxillary canine and CA(r= -0.74, P<0.01). The linear regression analysis showed an R² of 0.58, a root mean square error of 5.85, and a mean absolute error of 4.31. Conclusion: Linear regression using the PTVR can be effectively applied to predict CA in Indonesian adults between 20 and 49.99 years of age. As models of this type can be population-specific, recalibration for each population is encouraged. Additionally, future research should explore the use of other teeth, such as molars.

• The korean journal of orthodontics
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• v.53 no.2
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• pp.67-76
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• 2023

Objective: Morphometric and morphological evaluation of the mandibular condyle in adults and to identify its correlation with skeletal malocclusion patterns. Methods: Cone-beam computed tomography scans of 135 adult patients were used in this study and classified into groups according to four criteria: (1) sex (male and female); (2) sagittal skeletal discrepancy (Class I, Class II, and Class III); (3) vertical skeletal discrepancy (hyperdivergent, normodivergent, and hypodivergent); and age (group 1 ≤ 20 years, 21 ≤ group 2 < 30, and group 3 ≥ 30 years). The morphometrical variables were mandibular condyle height and width, and the morphological variable was the mandibular condyle shape in coronal and sagittal sections. Three-dimensional standard tessellation language files were created using itk-snap (open-source software), and measurements were performed using Meshmixer (open-source software). Results: The mandibular condyle height was significantly greater (p < 0.05) in patients with class III malocclusion than in those with class I or II malocclusion; the mandibular condyle width was not significantly different among different sexes, age groups, and sagittal and vertical malocclusions. There were no statistical associations between various mandibular condyle shapes and the sexes, age groups, and skeletal malocclusions. Conclusions: The condylar height was greatest in patients with class III malocclusion. The condylar height and width were greater among males than in females. The mandibular condyle shapes observed in sagittal and coronal sections did not affect the skeletal malocclusion patterns.