scholarly journals A new segmentation algorithm for measuring CBCT images of nasal airway: a pilot study

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6246 ◽  
Author(s):  
Chen Zhang ◽  
Robin Bruggink ◽  
Frank Baan ◽  
Ewald Bronkhorst ◽  
Thomas Maal ◽  
...  

Background Three-dimensional (3D) modeling of the nasal airway space is becoming increasingly important for assessment in breathing disorders. Processing cone beam computed tomography (CBCT) scans of this region is complicated, however, by the intricate anatomy of the sinuses compared to the simpler nasopharynx. A gold standard for these measures also is lacking. Previous work has shown that software programs can vary in accuracy and reproducibility outcomes of these measurements. This study reports the reproducibility and accuracy of an algorithm, airway segmentor (AS), designed for nasal airway space analysis using a 3D printed anthropomorphic nasal airway model. Methods To test reproducibility, two examiners independently used AS to edit and segment 10 nasal airway CBCT scans. The intra- and inter-examiner reproducibility of the nasal airway volume was evaluated using paired t-tests and intraclass correlation coefficients. For accuracy testing, the CBCT data for pairs of nasal cavities were 3D printed to form hollow shell models. The water-equivalent method was used to calculate the inner volume as the gold standard, and the models were then embedded into a dry human skull as a phantom and subjected to CBCT. AS, along with the software programs MIMICS 19.0 and INVIVO 5, was applied to calculate the inner volume of the models from the CBCT scan of the phantom. The accuracy was reported as a percentage of the gold standard. Results The intra-examiner reproducibility was high, and the inter-examiner reproducibility was clinically acceptable. AS and MIMICS presented accurate volume calculations, while INVIVO 5 significantly overestimated the mockup of the nasal airway volume. Conclusion With the aid of a 3D printing technique, the new algorithm AS was found to be a clinically reliable and accurate tool for the segmentation and reconstruction of the nasal airway space.

2019 ◽  
Vol 90 (1) ◽  
pp. 92-99 ◽  
Author(s):  
Maria Eduarda Assad Duarte ◽  
Bruno Frazão Gribel ◽  
Alice Spitz ◽  
Flavia Artese ◽  
José Augusto Mendes Miguel

ABSTRACT Objective To evaluate the reproducibility of digital tray transfer fit on digital indirect bonding by analyzing the differences in bracket positions. Materials and Methods Digital indirect bonding was performed by positioning brackets on digital models superimposed by tomography using Ortho Analyzer (3Shape) software. Thirty-three orthodontists performed indirect bonding on prototyped models of the same malocclusion using prototyped transfer trays for two types of brackets (MiniSprint Roth and BioQuick self-ligating). The models with brackets were scanned using an intraoral scanner (Trios, 3Shape). Superimpositions were made between the digital models obtained after indirect bonding and those from the original virtual setup. To analyze the differences in bracket positions, three planes were examined for each bracket: vertical, horizontal, and angulation. Three orthodontists repeated indirect bonding after 15 days, and Bland-Altman plots and intraclass correlation coefficients were used to evaluate inter- and intraevaluator reproducibility and reliability, respectively. Repeated-measures analysis of variance (ANOVA) was used to analyze the differences between bracket positions, and multivariate ANOVA was used to evaluate the influence of orthodontists' experience on the results. Results Differences between bracket positions were not statistically significant, except mesial-distal discrepancies in the BioQuick group (P = .016). However, differences were not clinically significant (horizontal varied from 0.04 to 0.13 mm; angulation, 0.45° to 2.03°). There was no significant influence of orthodontist experience and years of clinical practice on bracket positions (P = .314 and P = .158). The reproducibility among orthodontists was confirmed. Conclusions The reproducibility of digital indirect bonding was confirmed in terms of bracket positions using three-dimensional printed transfer trays.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pieter-Jan Verhelst ◽  
H. Matthews ◽  
L. Verstraete ◽  
F. Van der Cruyssen ◽  
D. Mulier ◽  
...  

AbstractAutomatic craniomaxillofacial (CMF) three dimensional (3D) dense phenotyping promises quantification of the complete CMF shape compared to the limiting use of sparse landmarks in classical phenotyping. This study assesses the accuracy and reliability of this new approach on the human mandible. Classic and automatic phenotyping techniques were applied on 30 unaltered and 20 operated human mandibles. Seven observers indicated 26 anatomical landmarks on each mandible three times. All mandibles were subjected to three rounds of automatic phenotyping using Meshmonk. The toolbox performed non-rigid surface registration of a template mandibular mesh consisting of 17,415 quasi landmarks on each target mandible and the quasi landmarks corresponding to the 26 anatomical locations of interest were identified. Repeated-measures reliability was assessed using root mean square (RMS) distances of repeated landmark indications to their centroid. Automatic phenotyping showed very low RMS distances confirming excellent repeated-measures reliability. The average Euclidean distance between manual and corresponding automatic landmarks was 1.40 mm for the unaltered and 1.76 mm for the operated sample. Centroid sizes from the automatic and manual shape configurations were highly similar with intraclass correlation coefficients (ICC) of > 0.99. Reproducibility coefficients for centroid size were < 2 mm, accounting for < 1% of the total variability of the centroid size of the mandibles in this sample. ICC’s for the multivariate set of 325 interlandmark distances were all > 0.90 indicating again high similarity between shapes quantified by classic or automatic phenotyping. Combined, these findings established high accuracy and repeated-measures reliability of the automatic approach. 3D dense CMF phenotyping of the human mandible using the Meshmonk toolbox introduces a novel improvement in quantifying CMF shape.


2019 ◽  
Vol 90 (3) ◽  
pp. 397-404 ◽  
Author(s):  
Zhuoxing Xiao ◽  
Zijin Liu ◽  
Yan Gu

ABSTRACT Objective To evaluate three-dimensional (3D) accuracy and reliability of nonradiographic dentofacial images integrated with a two-step method. Methods 3D facial images, cone-beam computed tomography (CBCT) images and digital maxillary dental casts were obtained from 20 pre-orthodontic subjects. Digital dental casts were integrated into 3D facial images using a two-step method based on the anterior tooth area. 3D coordinate values of five dental landmarks were identified in both dentofacial images and CBCT images. The accuracy of the integration method was assessed with paired t-tests between dentofacial images and CBCT-based reference standards. Intraclass correlation coefficients (ICCs) were assessed for the reliability of dentofacial images and CBCT-based images. Analysis of variance and Kruskal-Wallis tests evaluated the accuracy of the method in different dimensions. Results There was no statistical difference between dentofacial images and CBCT reference standards in both translational and rotational dimensions (P &gt; .05). Translational mean absolute errors for full dentitions were within 0.42 mm and ICCs were over 0.998 in x, y, and z directions. Rotational mean absolute errors for full dentitions were within 0.92° and ICCs over 0.734 in pitch, yaw, and roll orientations. Integration errors were significantly greater in the first molar, z-translation, and pitch rotation (P &lt; .05). Conclusions Integrating 3D dentofacial images with the two-step method is precise and acceptable for clinical diagnostics and scientific purposes. Errors were greater in the molar region, z-translation, and pitch rotation.


2013 ◽  
Vol 93 (7) ◽  
pp. 967-974 ◽  
Author(s):  
Olaf Verschuren ◽  
Maremka Zwinkels ◽  
Marjolijn Ketelaar ◽  
Femke Reijnders-van Son ◽  
Tim Takken

BackgroundFor children with cerebral palsy (CP) who are able to walk or run, the 10-m shuttle run test is currently the test of choice to assess cardiorespiratory fitness. This test, however, has not yet been examined in wheelchair-using youth with CP.ObjectiveThe purpose of this study was to investigate the test-retest reproducibility and validity of the 10-m shuttle ride test (SRiT) in youth with CP.DesignRepeated measurements of the SRiT were obtained.MethodsTwenty-three individuals with spastic CP (18 boys, 5 girls; mean age=13.3 years, SD=3.6 years) using a manual wheelchair for at least part of the day participated in this study. During the study, all participants performed one graded arm exercise test (GAET) and 2 identical SRiTs within 2 weeks. Peak oxygen uptake (V̇o2peak), peak heart rate (HRpeak), and respiratory exchange ratio (RER) were recorded. Intraclass correlation coefficients (2,1), the smallest detectable difference, and the limits of agreement (LOA) were calculated. The association between the results of the SRiT and GAET was tested using Pearson correlation coefficients.ResultsIntraclass correlation coefficients (.99, 95% confidence interval=.98–1.00) for all variables indicated highly acceptable reproducibility. The LOA analysis revealed satisfactory levels of agreement. The SRiT variables demonstrated strong, significant positive correlations for V̇o2peak values obtained during the SRiT and the GAET (r=.84, P&lt;.01).LimitationsAlthough the GAET is considered the gold standard, the cardiorespiratory demand during the GAET was significantly lower compared with during the SRiT. Future studies should determine whether the GAET can still be accepted as the gold standard for upper-extremity exercise.ConclusionsThe SRiT is a reproducible and valid test for measuring cardiorespiratory fitness in youth with spastic CP who self-propel a manual wheelchair.


2001 ◽  
Vol 21 (10) ◽  
pp. 1146-1150 ◽  
Author(s):  
Jussi Hirvonen ◽  
Kjell Någren ◽  
Jaana Kajander ◽  
Jarmo Hietala

[11C]SCH 23390 is a standard ligand for positron emission tomography (PET) studies on striatal dopamine D1 receptors. Its usefulness for cortical D1 receptor quantification in human PET studies has been questioned but has not been addressed previously. The authors tested the reproducibility of [11C]SCH 23390 binding potential (BP) in cortical areas in five healthy volunteers using three-dimensional PET. Measurement of D1 receptor BP was reproducible in basal ganglia, as well as in all cortical areas studied (intraclass correlation coefficients between 0.81 and 0.92). The absolute variability in cortical areas was 9.21% ± 0.07%. The reproducibility of cortical D1 receptor BP measurement with [11C]SCH 23390 is equal to that observed with a more recent D1 -ligand, [11C]NNC 112. [11C]NNC 112 produces slightly higher specific-to-nonspecific binding ratios but has markedly slower kinetics resulting in a need for a longer scan time. These aspects should be considered when designing studies on the cortical D1 -like receptors.


2006 ◽  
Vol 43 (2) ◽  
pp. 129-137 ◽  
Author(s):  
Emeka Nkenke ◽  
Bernhard Lehner ◽  
Manuel Kramer ◽  
Gerd Haeusler ◽  
Stefanie Benz ◽  
...  

Objective To assess measurement errors of a novel technique for the three-dimensional determination of the degree of facial symmetry in patients suffering from unilateral cleft lip and palate malformations. Design Technical report, reliability study. Setting Cleft Lip and Palate Center of the University of Erlangen-Nuremberg, Erlangen, Germany. Patients The three-dimensional facial surface data of five 10-year-old unilateral cleft lip and palate patients were subjected to the analysis. Distances, angles, surface areas, and volumes were assessed twice. Main Outcome Measures Calculations were made for method error, intraclass correlation coefficient, and repeatability of the measurements of distances, angles, surface areas, and volumes. Results The method errors were less than 1 mm for distances and less than 1.5° for angles. The intraclass correlation coefficients showed values greater than .90 for all parameters. The repeatability values were comparable for cleft and noncleft sides. Conclusion The small method errors, high intraclass correlation coefficients, and comparable repeatability values for cleft and noncleft sides reveal that the new technique is appropriate for clinical use.


2016 ◽  
Vol 86 (6) ◽  
pp. 1004-1009 ◽  
Author(s):  
Asli Baysal ◽  
Ahmet Oguz Sahan ◽  
Mehmet Ali Ozturk ◽  
Tancan Uysal

ABSTRACT Objective: To evaluate the intraexaminer repeatability and interexaminer reproducibility of soft tissue landmarks on three-dimensional (3-D) stereophogrammetric images. Materials and Methods: Thirty-four stereophotogrammetric images were taken and 19 soft tissue points were identified. The images were obtained using the 3-DMD Face (3-DMD TM Ltd, Atlanta, Ga) system. Two examiners marked 34 images manually with a mouse-driven cursor 4 weeks apart. Intraexaminer marking differences were calculated and classified as &lt;0.5 mm, 0.5–1 mm, and &gt;1 mm. Intraclass correlation coefficients were calculated for intraexaminer reliability. A paired-samples t-test was used to evaluate the difference between the examiners. Interexaminer reproducibility was evaluated by kappa analysis. Statistical significance was set at P &lt; .05. Results: Only one landmark (labiale superior) had an intraexaminer marking difference less than 0.5 mm. Existing landmarks had an intraexaminer difference less than 1 mm, but higher than 0.5 mm. The intraclass correlation coefficients (ICCs) indicated good intraexaminer repeatability for both observers. The ICC range for examiners 1 and 2 was 0.986–1.000 and 0.990–1.000, respectively. Kappa scores showed good interexaminer agreement, especially on the z-axis. Conclusions: Except labiale superior, the soft tissue landmarks used in this study were shown to have moderate reproducibility, but the difference between the landmarks was less than 1 mm, and they had clinically acceptable reproducibility.


2019 ◽  
Vol 6 ◽  
pp. 205435811989269
Author(s):  
Tharshika Thangarasa ◽  
Dana Foisy ◽  
Julie Leidecker ◽  
Daniel J. Corsi ◽  
Hilary Meggison ◽  
...  

Background: Patients treated with peritoneal dialysis (PD) are at increased risk of developing mechanical complications such as dialysate leaks and hernias thought to be partially related to an increase in intra-abdominal pressure (IAP) secondary to dialysate in the abdomen. However, measurement of IAP requires specialized equipment that is not readily available in the home dialysis unit. Objectives: To develop a reliable method of measuring IAP in PD patients that could be easily used in the home dialysis unit. We hypothesized that the handheld Stryker pressure monitor would be suitable for this purpose via connection to the PD catheter. Design: Cross-sectional. Setting: Tertiary Care Hospital, Ottawa, Ontario, Canada. Patients: Patients who were having a PD catheter inserted via laparoscopic surgery at The Ottawa Hospital were recruited for the study. Measurements: With the patients at end-expiration, the IAP measured with the Stryker monitor connected to the PD catheter was compared with the insufflator pressures of 15, 10, and 5 mm Hg. Methods: Bland-Altman plots were constructed and intraclass correlation coefficients were calculated for each pressure. Results: Twelve patients participated in the study: 9 men and 3 women. They were on average 53 ± 15 years old and 81 ± 13.4 kg. Two patients had to be excluded from the analysis due to difficulties zeroing the Stryker pressure monitor at the time of surgery. There were also rapid fluctuations in the insufflator pressure recording, creating additional challenges in comparing the 2 measurements at end-expiration. The 95% limits of agreement for the Bland-Altman plots ranged from 7.9 (@15 mm Hg) to 12.2 (@10 mm Hg). The intraclass correlation coefficients for reliability of the individual measurements ranged from 0.015 (10 mm Hg) to 0.634 (15 mm Hg). Limitations: Small sample size and lack of a gold standard comparator may have affected our results. Conclusions: In our study, we used the operating room insufflator as the gold standard for measuring IAP. By Bland-Altman plots and intraclass correlation coefficients, the pressure values obtained with the Stryker pressure monitor were not a reliable estimate of insufflator IAP especially at lower pressures. Further studies are needed to identify an ideal tool for measurement of IAP to guide PD management.


2020 ◽  
pp. 193229682097465
Author(s):  
Joel Willem Johan Lasschuit ◽  
Jill Featherston ◽  
Katherine Thuy Trang Tonks

Background: In an era of increasing technology and telehealth utilization, three-dimensional (3D) wound cameras promise reliable, rapid, and touch-free ulceration measurements. However, reliability data for commercially available devices in the diabetes foot service setting is lacking. We aimed to evaluate the reliability of diabetes-related foot ulceration measurement using a 3D wound camera in comparison to the routinely used ruler and probe. Method: Participants were prospectively recruited from a tertiary interdisciplinary diabetes foot service. Ulcerations were measured at each visit by two blinded observers, first by ruler and probe, and then using a 3D wound camera twice. Reliability was evaluated using intraclass correlation coefficients (ICC). Measurement methods were compared by Pearson correlation. Results: Sixty-three ulcerations affecting 38 participants were measured over 122 visits. Interobserver reliability of ruler measurement was excellent for estimated area (ICC 0.98, 95% CI 0.97-0.98) and depth (ICC 0.93, 95% CI 0.90-0.95). Intraobserver and interobserver reliability of the 3D wound camera area was excellent (ICC 0.96, 95%CI 0.95-0.97 and 0.97 95% CI 0.96-0.98, respectively). Depth was unrecordable in over half of 3D wound camera measurements, and reliability was inferior to probe measurement. Area correlation between methods was good ( R = 0.88 and 0.94 per observer); however, depth correlation was poor ( R = 0.49 and 0.65). Conclusions: 3D wound cameras offer practical advantages over ruler-based measurement. In diabetes-related foot ulceration, the reliability and comparability of area measurement was excellent across both methods, although depth was more reliably obtained by the probe. These limitations, together with cost, are important considerations if implementing this technology in diabetes foot care.


2019 ◽  
Vol 3 ◽  
pp. 247154921882498 ◽  
Author(s):  
Peter N Chalmers ◽  
Thomas Suter ◽  
Matthijs Jacxsens ◽  
Yue Zhang ◽  
Chong Zhang ◽  
...  

Introduction The purposes of this study were to determine (1) whether glenoid inclination (GI) could be accurately measured on plain radiographs as compared to a gold-standard 3-dimensional (3D) measure and (2) whether GI could be reliably measured on plain radiographs. Materials and Methods Digitally reconstructed radiographs (DRRs) were made from 3D computed tomography reconstructions of 68 normal cadaver scapulae. DRRs were made in a variety of viewing angles. Inclination was measured on these DRRs. These measurements were also made using a gold-standard 3D method. Measurements were made by 2 orthopedic surgeons and 1 surgeon twice, to calculate interrater and intrarater intraclass correlation coefficients (ICCs). Results The gold-standard 3D β was 83 ± 5° (72°–98°). On neutral plain radiographs, the mean ± standard deviation 2D β angle was 80 ± 6° (range, 66°–99°). With regard to accuracy, the 2D β angle was significantly different from the 3D β angle, with the 2D β underestimating the 3D β by 5° (95% confidence intervals −1 to 12). With regard to reliability, interrater ICCs for 2D β with a neutral viewing angle was 0.79. Two-dimensional β varied widely with viewing angle from 0.24 to 0.88. Interrater ICCs for the 3D method was 0.83 (0.60–0.92). Intrarater ICCs for all 3 techniques were high (>0.91). Conclusions Two-dimensional radiographic GI measurement is not accurate, as it underestimates the 3D value by an average of 5° when compared to the gold-standard 3D measurement. GI 2D measurement reliability varies with viewing angle on plain radiographs and thus to accurately and reliably measure inclination 3D imaging is necessary.


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