scholarly journals Reproducibility of three-dimensional landmarking and Frankfort horizontal plane construction: a comparison of conventional and novel landmarks in presurgical computed tomography scans

2021 ◽  
Author(s):  
Gauthier Dot ◽  
Frederic Rafflenbeul ◽  
Adeline Kerbrat ◽  
Philippe Rouch ◽  
Laurent Gajny ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Ct Scan ◽  
Three Dimensional ◽  
Computed Tomography Scans ◽  
Repeatability And Reproducibility ◽  
Frankfort Horizontal Plane ◽  
Cephalometric Measurements ◽  
Iso 5725 ◽  
Overall Reliability ◽  
3D Landmarks

Objectives To assess manual landmarking repeatability and reproducibility (R&R) of a set of three-dimensional (3D) landmarks and to evaluate R&R of vertical cephalometric measurements using two Frankfort Horizontal (FH) planes as references for horizontal 3D imaging reorientation. Methods Thirty-three landmarks, divided into "conventional", "foraminal" and "dental", were manually located twice by 3 experienced operators on 20 computed tomography (CT) scans of orthognathic surgery patients. R&R of the landmark localization were computed according to the ISO 5725 standard. These landmarks were then used to construct 2 FH planes: a conventional FH plane (orbitale left, porion right and left) and a newly proposed FH plane (midinternal acoustic foramen, orbitale right and left). R&R of vertical cephalometric measurements were computed using these 2 FH planes as horizontal references for CT reorientation. Results Landmarks showing a 95% confidence interval (CI) of repeatability and/or reproducibility > 2mm were found exclusively in the "conventional" landmarks group. Vertical measurements showed excellent R&R (95% CI < 1mm) with either FH plane as horizontal reference. However, the 2 FH planes were not found to be parallel (absolute angular difference of 2.41°, SD 1.27°). The average time needed to landmark one CT scan was 14 ± 3 minutes. Conclusions The "dental" and "foraminal" landmarks tended to be more reliable than the "conventional" landmarks. Despite the poor overall reliability of the landmarks orbitale and porion, the construction of the conventional FH plane using 3 landmarks provided a reliable horizontal reference for 3D craniofacial CT scan reorientation.

scholarly journals Three-Dimensional Cephalometric Landmarking and Frankfort Horizontal Plane Construction: Reproducibility of Conventional and Novel Landmarks

2021 ◽  
Vol 10 (22) ◽  
pp. 5303
Author(s):  
Gauthier Dot ◽  
Frédéric Rafflenbeul ◽  
Adeline Kerbrat ◽  
Philippe Rouch ◽  
Laurent Gajny ◽  
...  
Keyword(s):  
Orthognathic Surgery ◽  
Three Dimensional ◽  
Ct Scans ◽  
Angular Difference ◽  
Dentofacial Deformity ◽  
Repeatability And Reproducibility ◽  
Frankfort Horizontal Plane ◽  
Cephalometric Measurements ◽  
Iso 5725 ◽  
3D Landmarks

In some dentofacial deformity patients, especially patients undergoing surgical orthodontic treatments, Computed Tomography (CT) scans are useful to assess complex asymmetry or to plan orthognathic surgery. This assessment would be made easier for orthodontists and surgeons with a three-dimensional (3D) cephalometric analysis, which would require the localization of landmarks and the construction of reference planes. The objectives of this study were to assess manual landmarking repeatability and reproducibility (R&R) of a set of 3D landmarks and to evaluate R&R of vertical cephalometric measurements using two Frankfort Horizontal (FH) planes as references for horizontal 3D imaging reorientation. Thirty-three landmarks, divided into “conventional”, “foraminal” and “dental”, were manually located twice by three experienced operators on 20 randomly-selected CT scans of orthognathic surgery patients. R&R confidence intervals (CI) of each landmark in the -x, -y and -z directions were computed according to the ISO 5725 standard. These landmarks were then used to construct 2 FH planes: a conventional FH plane (orbitale left, porion right and left) and a newly proposed FH plane (midinternal acoustic foramen, orbitale right and left). R&R of vertical cephalometric measurements were computed using these 2 FH planes as horizontal references for CT reorientation. Landmarks showing a 95% CI of repeatability and/or reproducibility > 2 mm were found exclusively in the “conventional” landmarks group. Vertical measurements showed excellent R&R (95% CI < 1 mm) with either FH plane as horizontal reference. However, the 2 FH planes were not found to be parallel (absolute angular difference of 2.41°, SD 1.27°). Overall, “dental” and “foraminal” landmarks were more reliable than the “conventional” landmarks. Despite the poor reliability of the landmarks orbitale and porion, the construction of the conventional FH plane provided a reliable horizontal reference for 3D craniofacial CT scan reorientation.

Correlation between tympanometry volume and three-dimensional computed tomography mastoid volumetry in tympanoplasty candidates

2021 ◽  
pp. 1-5
Author(s):  
L Epprecht ◽  
L Qingsong ◽  
N Stenz ◽  
S Hashimi ◽  
T Linder
Keyword(s):  
Computed Tomography ◽  
Tympanic Membrane ◽  
Cell Volume ◽  
Radiation Injury ◽  
Three Dimensional ◽  
Non Invasive ◽  
Tympanic Membrane Perforations ◽  
Computed Tomography Scans ◽  
Air Cells ◽  
Mastoid Air Cells

Abstract Objective Ventilation of the middle ear and mastoid air cells is believed to play an important role in the pathogenesis of chronic ear disease. Traditionally, ventilation is assessed by computed tomography. However, this exposes patients to cumulative radiation injury. In cases with a perforation in the tympanic membrane, tympanometry potentially presents a non-invasive alternative to measure the ventilated middle-ear and mastoid air cell volume. This study hypothesised that total tympanometry volume correlates with ventilated middle-ear and mastoid air cell volume. Method Total tympanometry volume was compared with ventilated middle-ear and mastoid air cell volume on computed tomography scans in 20 tympanic membrane perforations. Results There was a high correlation between tympanometry and computed tomography volumes (r = 0.78; p < 0.001). A tympanometry volume more than 2 ml predicted good ventilation on computed tomography. Conclusion These results may help reduce the need for pre-operative computed tomography in uncomplicated cases with tympanic membrane perforations.

Incidence of persistent metopic suture in Australia: findings from 1034 three-dimensional computed tomography scans

2021 ◽  
Author(s):  
Sarut Chaisrisawadisuk ◽  
Sarah Constantine ◽  
Nicolene Lottering ◽  
Mark H. Moore ◽  
Peter J. Anderson
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Computed Tomography Scans ◽  
Metopic Suture

scholarly journals Repeatability and reproducibility of landmarks--a three-dimensional computed tomography study

2011 ◽  
Vol 34 (3) ◽  
pp. 276-286 ◽  
Author(s):  
I. Titiz ◽  
M. Laubinger ◽  
T. Keller ◽  
K. Hertrich ◽  
U. Hirschfelder
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Repeatability And Reproducibility

A volumetric three-dimensional evaluation of invasiveness of an endoscopic and microscopic approach for transmeatal visualisation of the middle ear

2021 ◽  
pp. 1-5
Author(s):  
A H A Baazil ◽  
J G G Dobbe ◽  
E van Spronsen ◽  
F A Ebbens ◽  
F G Dikkers ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Middle Ear ◽  
Three Dimensional ◽  
Endoscopic Approach ◽  
Microscopic Approach ◽  
Significant Difference ◽  
Computed Tomography Scans ◽  
The Difference ◽  
Group 2 ◽  
Group 1

Abstract Objective This study aimed to compare the necessary scutum defect for transmeatal visualisation of middle-ear landmarks between an endoscopic and microscopic approach. Method Human cadaveric heads were used. In group 1, middle-ear landmarks were visualised by endoscope (group 1 endoscopic approach) and subsequently by microscope (group 1 microscopic approach following endoscopy). In group 2, landmarks were visualised solely microscopically (group 2 microscopic approach). The amount of resected bone was evaluated via computed tomography scans. Results In the group 1 endoscopic approach, a median of 6.84 mm3 bone was resected. No statistically significant difference (Mann–Whitney U test, p = 0.163, U = 49.000) was found between the group 1 microscopic approach following endoscopy (median 17.84 mm3) and the group 2 microscopic approach (median 20.08 mm3), so these were combined. The difference between the group 1 endoscopic approach and the group 1 microscopic approach following endoscopy plus group 2 microscopic approach (median 18.16 mm3) was statistically significant (Mann–Whitney U test, p < 0.001, U = 18.000). Conclusion This study showed that endoscopic transmeatal visualisation of middle-ear landmarks preserves more of the bony scutum than a microscopic transmeatal approach.

scholarly journals Three-dimensional (3D) Models Based on Pre-operative Computed Tomography Scans to Personalize the Planned Liver Surgery in Complex Cases

HPB ◽  
2021 ◽  
Vol 23 ◽  
pp. S860-S861
Author(s):  
L. Alaimo ◽  
F. Bagante ◽  
A. Ruzzenente ◽  
M. De Bellis ◽  
S. Conci ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Liver Surgery ◽  
Three Dimensional ◽  
3D Models ◽  
Computed Tomography Scans ◽  
Complex Cases

The Hyoid Bone in Malay Infants with Cleft Lip and Palate

2006 ◽  
Vol 43 (5) ◽  
pp. 532-538 ◽  
Author(s):  
Zainul A. Rajion ◽  
Grant C. Townsend ◽  
David J. Netherway ◽  
Peter J. Anderson ◽  
Toby Hughes ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Cervical Spine ◽  
Software Package ◽  
Hyoid Bone ◽  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Three Dimensional ◽  
Cross Sectional ◽  
Computed Tomography Scans ◽  
Age Range

Objective: To compare morphological and positional variations of the hyoid bone in unoperated infants with cleft lip and palate (CL/P) with those in noncleft infants. Design: Retrospective, cross sectional. Patients and Methods: Three-dimensional computed tomography scans were obtained from 29 unoperated CL/P infants of Malay origin aged between 0 and 12 months and from 12 noncleft infants in the same age range. Observations were made and measurements were obtained with a software package developed at the Australian Craniofacial Unit. The sizes of the hyoid bones and the position of the hyoid body and epiglottis in relation to the cervical spine were measured. Anatomical anomalies of the hyoid and prevalence of aspiration pneumonia were also documented. Results: The hyoid bones and epiglottis were found to be located more inferiorly in CL/P infants compared with the noncleft infants. Also, 17% (5/29) of the CL/P infants had nonossified hyoid bodies. Conclusion: The results suggest that there are differences in the location and genesis of the hyoid bone in infants with CL/P that warrant further investigation.

scholarly journals Efficacy of a hydrogel spacer in three-dimensional conformal radiation therapy for prostate cancer

2020 ◽  
Vol 50 (3) ◽  
pp. 303-309 ◽  
Author(s):  
Mami Ogita ◽  
Hideomi Yamashita ◽  
Subaru Sawayanagi ◽  
Wataru Takahashi ◽  
Keiichi Nakagawa
Keyword(s):  
Prostate Cancer ◽  
Computed Tomography ◽  
High Risk ◽  
Seminal Vesicle ◽  
Three Dimensional ◽  
Conformal Radiotherapy ◽  
Computed Tomography Scans ◽  
Before And After ◽  
Three Dimensional Conformal Radiotherapy ◽  
Dose Constraints

Abstract Objectives We aimed to compare the dose constraints fulfillment rate of the three-dimensional conformal radiotherapy treatment plan before and after a hydrogel spacer insertion. Methods The planning computed tomography scans of 39 patients who received stereotactic body radiotherapy for prostate cancer were used. All patients inserted a hydrogel spacer and underwent computed tomography scans before and after spacer insertion. The three-dimensional conformal radiotherapy plans according to NCCN classification, low-, intermediate- and high-risk, were made for each patient. Clinical target volume included prostate and seminal vesicle 2 cm for high risk, prostate and seminal vesicle 1 cm for intermediate risk and prostate only for low risk. Three-dimensional conformal radiotherapy including a seven-field conformal technique with 76 Gy in 38 fractions. Dose constraints for rectum and bladder were V70 Gy ≤ 15%, V65 Gy ≤ 30% and V40 Gy ≤ 60%. Results Among 39 patients, 35 (90%), 19 (49%) and 13 (33%) and 38 (97%), 38 (97%) and 34 (87%) patients before and after the spacer insertion fulfilled rectum dose constraints for low-, intermediate- and high-risk plans, respectively. A hydrogel spacer significantly reduced rectum dose and improved the rectum dose constraints fulfillment rate in intermediate (P &lt; 0.01) and high (P &lt; 0.01), but no difference was found in low-risk plan (P = 0.25). On multivariate analysis, spacer use was associated with the higher rectum dose constraints fulfillment rate. Conclusions A hydrogel spacer reduced rectum dose and improved the dose constraints fulfillment rate in three-dimensional conformal radiotherapy plan. Although IMRT is the standard treatment, 3D-CRT using a hydrogel spacer may be a treatment option.

scholarly journals The correlation between the teardrop angle and anterior lunate facet displacement in plating distal radial fractures

2019 ◽  
Vol 44 (5) ◽  
pp. 462-467 ◽  
Author(s):  
Teun Teunis ◽  
Sjoerd Meijer ◽  
Jesse Jupiter ◽  
Daniel Rikli ◽  
Keyword(s):  
Computed Tomography ◽  
Surface Area ◽  
Plate Fixation ◽  
Three Dimensional ◽  
Anterior Plate ◽  
Distal Radial Fractures ◽  
Computed Tomography Scans ◽  
Before And After ◽  
Anterior Plating ◽  
Three Dimensional Models

This study aimed to determine the association of teardrop angle and anteroposterior distance with anterior lunate facet displacement and articular congruity before and after anterior plating of distal radial fractures. We included 36 patients with complete intra-articular distal radial fractures with separate anterior lunate facet fragments. On radiographs we determined the teardrop angle and anteroposterior distance. On digital three-dimensional models we measured proximal-distal, anteroposterior and ulnoradial anterior lunate facet displacement, and we outlined the gap surface area. Preoperatively, teardrop angle was highly associated with the extent of anterior lunate facet displacement. Increased anteroposterior distance was mainly associated with articular incongruity after anterior plate fixation. This information may reduce the need of preoperative computed tomography scans in fractures with a normal tear drop angle. This is particularly useful in low-resource settings.

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