scholarly journals Studying Primate Carpal Kinematics in Three Dimensions Using a Computed-Tomography-Based Markerless Registration Method

2010 ◽  
Vol 293 (4) ◽  
pp. 692-709 ◽  
Author(s):  
Caley M. Orr ◽  
Evan L. Leventhal ◽  
Spencer F. Chivers ◽  
Mary W. Marzke ◽  
Scott W. Wolfe ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Three Dimensions ◽  
Registration Method ◽  
Carpal Kinematics

Development and Validation of a Computed Tomography-Based Methodology to Measure Carpal Kinematics

2005 ◽  
Vol 127 (3) ◽  
pp. 541-548 ◽  
Author(s):  
Jamie Pfaeffle ◽  
Brad Blankenhorn ◽  
Kathryne Stabile ◽  
Joseph Imbriglia ◽  
Robert Goitz ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Distal Radius ◽  
Three Dimensions ◽  
Surface Matching ◽  
Helical Axis ◽  
Wrist Flexion ◽  
Commercial Software ◽  
Flexion Extension ◽  
Surface Models ◽  
Carpal Kinematics

Motion of the wrist bones is complicated and difficult to measure. Noninvasive measurement of carpal kinematics using medical images has become popular. This technique is difficult and most investigators employ custom software. The objective of this paper is to describe a validated methodology for measuring carpal kinematics from computed tomography (CT) scans using commercial software. Four cadaveric wrists were CT imaged in neutral, full flexion, and full extension. A registration block was attached to the distal radius and used to align the data sets from each position. From the CT data, triangulated surface models of the radius, lunate, and capitate bones were generated using commercial software. The surface models from each wrist position were read into engineering design software that was used to calculate the centroid (position) and principal mass moments of inertia (orientation) of (1) the capitate and lunate relative to the fixed radius and (2) the capitate relative to the lunate. These data were used to calculate the helical axis kinematics for the motions from neutral to extension and neutral to flexion. The kinematics were plotted in three dimensions using a data visualization software package. The accuracy of the method was quantified in a separate set of experiments in which an isolated capitate bone was subjected to two different known rotation/translation motions for ten trials each. For comparison to in vivo techniques, the error in distal radius surface matching was determined using the block technique as a gold standard. The motion that the lunate and capitate underwent was half that of the overall wrist flexion-extension range of motion. Individually, the capitate relative to the lunate and the lunate relative to the radius generally flexed or extended about 30 deg, while the entire wrist (capitate relative to radius) typically flexed or extended about 60 deg. Helical axis translations were small, ranging from 0.6 mm to 1.8 mm across all motions. The accuracy of the method was found to be within 1.4 mm and 0.5 deg (95% confidence intervals). The mean error in distal radius surface matching was 2.4 mm and 1.2 deg compared to the use of a registration block. Carpal kinematics measured using the described methodology were accurate, reproducible, and similar to findings of previous investigators. The use of commercially available software should broaden the access of researchers interested in measuring carpal kinematics using medical imaging.

scholarly journals Cone-beam computed tomography evaluation on the condylar displacement following sagittal split ramus osteotomy in asymmetric setback patients: Comparison between conventional approach and surgery-first approach

2017 ◽  
Vol 87 (5) ◽  
pp. 733-738 ◽  
Author(s):  
Min-Hee Oh ◽  
Hyeon-Shik Hwang ◽  
Kyung-Min Lee ◽  
Jin-Hyoung Cho
Keyword(s):  
Computed Tomography ◽  
Correlation Analysis ◽  
Cone Beam Computed Tomography ◽  
Facial Asymmetry ◽  
Three Dimensions ◽  
Conventional Group ◽  
Cone Beam ◽  
Sagittal Split Ramus Osteotomy ◽  
Surgery First ◽  
Condylar Displacement

ABSTRACT Objective: To compare the condylar displacement following sagittal split ramus osteotomy (SSRO) in asymmetric setback patients between the conventional approach and surgery-first approach and to determine whether the condylar displacement is affected by asymmetric setback in SSRO patients. Materials and Methods: This was a retrospective study. The subjects consisted of patients with facial asymmetry who underwent SSRO and had cone-beam computed tomography taken before and 1 month after surgery. They were allocated into the conventional (n = 18) and surgery-first (SF) groups (n = 20). Descriptive, independent t-tests and Pearson correlation analysis were computed. Results: The amount of condylar displacement in x-, y-, and z-directions and Euclidean distance showed no statistically significant differences between the conventional and SF groups. Comparing the postoperative condylar position with the preoperative position, the condylar displacement occurred in posterior (P < .05) and downward (P < .05) directions in both groups except on the deviated side in the conventional group. The condylar displacement occurred in a posterior (P < .05) direction on the deviated side of the conventional group. However, the condylar displacement in three dimensions showed no statistically significant differences between the two groups. In the correlation analysis, the condylar displacement in both the deviated and contralateral sides showed no significant correlation with asymmetric setback in either group. Conclusion: The condylar displacement in three dimensions and the distance of condylar displacement in SSRO patients with facial asymmetry showed no significant difference between conventional and SF groups. Condylar displacement was not associated with asymmetric setback.

scholarly journals Assessment of dehiscence and fenestration in children and adolescents using cone beam computed tomography

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Aslıhan Akbulut ◽  
Beyza Ballı Akgöl ◽  
Kaan Orhan ◽  
Merve Bayram
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Primary Teeth ◽  
Three Dimensions ◽  
Cone Beam ◽  
Permanent Teeth ◽  
Type I ◽  
Chi Square ◽  
Children And Adolescent ◽  
Adolescent Patients

Objectives: To define the prevalence of dehiscence and fenestration and classify them in terms of the localization of fenestrations in a random sampled group of children and adolescent patients using cone-beam computed tomography (CBCT).Methods:  CBCT performed at the Department of Oral and Maxillofacial Radiology of patients referred by the paediatric dentistry clinic were included in this retrospective study. Image evaluations were performed by dentomaxillofacial radiologist (AA, asst. prof.), and these images were examined in three dimensions of the axial, coronal, and sagittal planes. Intraexaminer agreement for the evaluations were found acceptable. The presence/absence of dehiscence and/or fenestration, fenestration’s classification type, and localization of defects were recorded. Moreover, the presence/absence of periapical lesion in related root with dehiscence and fenestration was noted. For statistical analysis, The Chi-Square test, Fisher Freeman Halton Test, and Yates' Continuity of Correction were used.Results: 3061 roots in 1801 teeth of 120 cases were analyzed. The mean age was 9.97±2.22 years. Dehiscence was detected in 261(8.5%) roots of 161(8.9%) teeth, and fenestration was detected 63(2%) roots of 36(2%) teeth. The most common fenestration type was Type I, followed by Type II and IV. Dehiscence was observed more frequently in primary teeth than permanent teeth, and the difference was statistically significant (p:0.000). Dehiscence and fenestration incidence in maxillary teeth was significantly higher than in the mandibular teeth (pdehiscence:0.000, pfenestration:0.004). Apical lesions were observed more in primary teeth than permanent teeth for both defects.Conclusions: This study concludes that alveolar dehiscence and fenestrations are more common in primary teeth than permanent teeth. Moreover, these defects were detected more for the teeth in the maxilla. Concerning endodontic and orthodontic therapies in maxilla, use of CBCT is useful in determining the region's anatomical structure accurately in suspected cases of child and adolescent patients.

scholarly journals Gold Exploration in Two and Three Dimensions: Improved and Correlative Insights from Microscopy and X-Ray Computed Tomography

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 476
Author(s):  
Joshua Chisambi ◽  
Bjorn von der Heyden ◽  
Muofhe Tshibalanganda ◽  
Stephan Le Roux
Keyword(s):  
Computed Tomography ◽  
Spatial Distribution ◽  
Gold Mineralization ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Low Grade ◽  
X Ray ◽  
3D Space ◽  
X Ray Computed ◽  
2D And 3D

In this contribution, we highlight a correlative approach in which three-dimensional structural/positional data are combined with two dimensional chemical and mineralogical data to understand a complex orogenic gold mineralization system; we use the Kirk Range (southern Malawi) as a case study. Three dimensional structures and semi-quantitative mineral distributions were evaluated using X-ray Computed Tomography (XCT) and this was augmented with textural, mineralogical and chemical imaging using Scanning Electron Microscopy (SEM) and optical microscopy as well as fire assay. Our results detail the utility of the correlative approach both for quantifying gold concentrations in core samples (which is often nuggety and may thus be misrepresented by quarter- or half-core assays), and for understanding the spatial distribution of gold and associated structures and microstructures in 3D space. This approach overlays complementary datasets from 2D and 3D analytical protocols, thereby allowing a better and more comprehensive understanding on the distribution and structures controlling gold mineralization. Combining 3D XCT analyses with conventional 2D microscopies derive the full value out of a given exploration drilling program and it provides an excellent tool for understanding gold mineralization. Understanding the spatial distribution of gold and associated structures and microstructures in 3D space holds vast potential for exploration practitioners, especially if the correlative approach can be automated and if the resultant spatially-constrained microstructural information can be fed directly into commercially available geological modelling software. The extra layers of information provided by using correlative 2D and 3D microscopies offer an exciting new tool to enhance and optimize mineral exploration workflows, given that modern exploration efforts are targeting increasingly complex and low-grade ore deposits.

Validation of a New Method for 2D Fusion Imaging Registration in a System Prepared Only for 3D

2020 ◽  
Vol 27 (3) ◽  
pp. 468-472
Author(s):  
Andreas Edsfeldt ◽  
Björn Sonesson ◽  
Helena Rosén ◽  
Marcelo H. Petri ◽  
Kiattisak Hongku ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Radiation Exposure ◽  
Imaging System ◽  
Endovascular Aneurysm Repair ◽  
Fusion Imaging ◽  
Operating Table ◽  
3D Registration ◽  
Registration Method ◽  
Dose Area Product ◽  
Single Frame

Purpose: To validate a new 2D-3D registration method of fusion imaging during aortic repair in a system prepared only for 3D-3D registration and to compare radiation doses and accuracy. Materials and Methods: The study involved 189 patients, including 94 patients (median age 70 years; 85 men) who underwent abdominal endovascular aneurysm repair (EVAR) with 2D-3D fusion on an Artis zee imaging system and 95 EVAR patients (median age 70 years; 81 men) from a prior study who had 3D-3D registration done using cone beam computed tomography (CBCT). For the 2D-3D registration, an offline CBCT of the empty operating table was imported into the intraoperative dataset and superimposed on the preoperative computed tomography angiogram (CTA). Then 2 intraoperative single-frame 2D images of the skeleton were aligned with the patient’s skeleton on the preoperative CTA to complete the registration process. A digital subtraction angiogram was done to correct any misalignment of the aortic CTA volume. Values are given as the median [interquartile range (IQR) Q1, Q3]. Results: The 2D-3D registration had an accuracy of 4.0 mm (IQR 3.0, 5.0) after bone matching compared with the final correction with DSA (78% within 5 mm). By applying the 2D-3D protocol the radiation exposure (dose area product) from the registration of the fusion image was significantly reduced compared with the 3D-3D registration [1.12 Gy∙cm2 (IQR 0.41, 2.14) vs 43.4 Gy∙cm2 (IQR 37.1, 49.0), respectively; p<0.001). Conclusion: The new 2D-3D registration protocol based on 2 single-frame images avoids an intraoperative CBCT and can be used for fusion imaging registration in a system originally designed for 3D-3D only. This 2D-3D registration protocol is accurate and leads to a significant reduction in radiation exposure.

Dose accumulation with deformable image registration method using helical tomotherapy images for prostate cancer

2019 ◽  
Vol 19 (1) ◽  
pp. 25-29
Author(s):  
Warit Thongsuk ◽  
Imjai Chitapanarux ◽  
Somsak Wanwilairat ◽  
Wannapha Nobnop
Keyword(s):  
Prostate Cancer ◽  
Computed Tomography ◽  
Image Registration ◽  
Cancer Patients ◽  
Helical Tomotherapy ◽  
Deformable Image Registration ◽  
High Dose ◽  
Registration Method ◽  
Dose Accumulation ◽  
Dose Volume

AbstractPurpose:To evaluate changes of accumulated doses from an initial plan in each fraction by deformable image registration (DIR) with daily megavoltage computed tomography (MVCT) images from helical tomotherapy for prostate cancer patients.Materials and methods:The MVCT images of five prostate cancer patients were acquired by using a helical tomotherapy unit before the daily treatment fraction began. All images data were exported to DIR procedures by MIM software, in which the planned kilovoltage computed tomography (kVCT) images were acting as the source images with the daily MVCT acquired as the target images for registration. The automatic deformed structure was used to access the volume variation and daily dose accumulation to each structure. All dose-volume parameters were compared to the initial planned dose.Results:The actual median doses of the planning target volume (PTV) received 70 Gy and 50.4 Gy were decreased at the end of the treatment with an average 1·0 ± 0·67% and 2·1 ± 1·54%, respectively. As regards organs at risk (OARs), the bladder and rectum dose-volume parameters tended to increase from the initial plan. The high-dose regions of the bladder and rectum, however, were decreased from the initial plan at the end of the treatment.Conclusions:The daily actual dose differs from the initial planned dose. The accumulated dose of target tends to be lower than the initial plan, but tends to be higher than the initial plan for the OARs. Therefore, inter-fractional anatomic changes should be considered by the DIR methods, which would be useful as clinically informative and beneficial for adaptive treatment strategies.

scholarly journals CBCT-Aided Microscopic and Ultrasonic Treatment for Upper or Middle Thirds Calcified Root Canals

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Ying-Ming Yang ◽  
Bin Guo ◽  
Li-Yang Guo ◽  
Yan Yang ◽  
Xiao Hong ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Great Risk ◽  
Ultrasonic Treatment ◽  
Root Canal ◽  
Three Dimensions ◽  
Cone Beam ◽  
Operating Microscope ◽  
Limited Information ◽  
Root Canals ◽  
Upper Third

Root canal calcification is considered a great challenge during root canal treatment. Although the application of ultrasonic instruments and dental operating microscope (DOM) has advantages, dealing with calcified root canals still suffers a great risk of failure because of limited information about the location, length, and direction of obliteration on periapical radiographs. In this work, a cone-beam computed tomography- (CBCT-) aided method aimed at solving complicated calcified root canals in which conventional approaches could not work was proposed. Thirteen teeth with sixteen calcified canals (12 calcified in the upper third, 4 calcified in the middle third), which cannot be negotiated with conventional methods, were treated with the aid of CBCT. The location of calcification and depth of instrumentation and operating direction were calculated and assessed in three dimensions with ultrasonic instruments under DOM. In all thirteen teeth, canals with upper and middle thirds calcification were treated successfully. Finally, a guideline was proposed to help achieve consistent apical patency in calcified canals.

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