Difference In Distance Research Articles

Interobserver variation in tumor delineation of liver metastases using Magnetic Resonance Imaging

Background and purposeMagnetic Resonance Imaging (MRI) guided stereotactic body radiotherapy (SBRT) of liver metastases is an upcoming high-precision non-invasive treatment. Interobserver variation (IOV) in tumor delineation, however, remains a relevant uncertainty for planning target volume (PTV) margins. The aims of this study were to quantify IOV in MRI-based delineation of the gross tumor volume (GTV) of liver metastases and to detect patient-specific factors influencing IOV. Materials and methodsA total of 22 patients with liver metastases from three primary tumor origins were selected (colorectal(8), breast(6), lung(8)). Delineation guidelines and planning MRI-scans were provided to eight radiation oncologists who delineated all GTVs. All delineations were centrally peer reviewed to identify outliers not meeting the guidelines. Analyses were performed both in- and excluding outliers. IOV was quantified as the standard deviation (SD) of the perpendicular distance of each observer’s delineation towards the median delineation. The correlation of IOV with shape regularity, tumor origin and volume was determined. ResultsIncluding all delineations, average IOV was 1.6 mm (range 0.6–3.3 mm). From 160 delineations, in total fourteen single delineations were marked as outliers after peer review. After excluding outliers, the average IOV was 1.3 mm (range 0.6–2.3 mm). There was no significant correlation between IOV and tumor origin or volume. However, there was a significant correlation between IOV and regularity (Spearman’s ρs = -0.66; p = 0.002). ConclusionMRI-based IOV in tumor delineation of liver metastases was 1.3–1.6 mm, from which PTV margins for IOV can be calculated. Tumor regularity and IOV were significantly correlated, potentially allowing for patient-specific margin calculation.

Treatment outcome in refractive accommodative esotropia

Background Accommodative esotropia (ET) usually presents in preschool years. It is often intermittent, and the deviation is typically eliminated by controlling the accommodative effort with optical correction of hypermetropia. Objective The aim of this study was to document the clinical features and to assess the functional outcome in patients with refractive accommodative esotropia (RAE) in terms of amblyopia and binocular vision and to analyze the possible risk factors involving the development of amblyopia. Patients and methods We retrospectively reviewed the records of 60 patients diagnosed with fully accommodative esotropia (FAET). Multiple parameters were reviewed, including age of onset, age of initiation of treatment, initial and final cycloplegic refraction, distance and near deviation with and without glasses, stereoacuity, presence of anisometropia, and change in hyperopia. Results The mean age of onset and age of initiation of treatment were 2.53±1.42 and 2.73±1.25 years, respectively. The mean spherical equivalent refraction at the initial visit was +5.36±1.48 diopters (D) in the right eyes and +5.62±1.43 D in the left eyes. Anisometropia was present in 33.33% of the patients. Fusion was achieved in 90% of the patients, with 38 (63.33%) patients having stereopsis ranging from 40–100 sec/arc and 22 (36.67%) having stereopsis between 100 and 200 sec/arc with the Titmus fly test. Amblyopia was reduced from 50% to 16.67%. Anisometropia was found to be the only statistically significant risk factor for the development of amblyopia (P<0.001). Hypermetropia showed a tendency either to remain stable or to increase over the first seven years of life and then tended to decrease. Conclusion Most of the patients with FAET have an excellent outcome in terms of visual acuity and binocular vision. Amblyopia is common among patients with RAE and the current management strategies resulted in marked reduction in the prevalence of amblyopia.

Territorial patterns of COVID-19 in Iran

Motives: Spatial analysis has become an essential tool in understanding the underlying factors that contribute to the distribution of viral pandemics, diseases, injuries, and mortality patterns. By visualizing geographical data in spatial maps, researchers can identify local distribution patterns and potential drivers behind these patterns. In health and medical sciences, there has been a growing recognition that spatial analysis and mapping techniques are helpful in addressing various challenges related to the allocation of healthcare resource in both urban and rural areas. Aim: The objective of this study was to analyze the spatial distribution pattern of the COVID-19 pandemic and the Index of Proximity Distribution (IPD) across 31 provinces of Iran between February 2019 and February 2023. A two-stage sampling method combining convenience and cluster sampling was used to examine COVID-19 distribution patterns in 31 provinces of Iran between 22 February 2020 and 22 February 2023. COVID-19 and IPD data were collected as part of this panel study. Data were analyzed using t-tests, chi-square tests, and analysis of variance (ANOVA) in SPSS version 28 (α = 0.05). Subsequently, daily COVID-19 infection data for each province in the analyzed period were processed in ArcGIS software, and the spatial distribution pattern of the pandemic in Iran were visualized by point density analysis. Standard distance and standard deviation ellipse techniques were employed to assess the density or dispersion of infected individuals and to determine the spatial distribution pattern of COVID-19 in Iran. A spatial autocorrelation (Moran’s I) analysis was conducted to identify the spatial distribution pattern of COVID-19 in Iran. Additionally, distance-based spatial autocorrelation was used to examine the prevalence of COVID-19 infection across Iranian provinces. In a grouping analysis, 31 Iranian provinces were classified into five groups based on the number of COVID-19 cases, and spatial statistics were used to examine the prevalence of COVID-19 within each group. A hot spot analysis and a standard distance (SD) analysis were conducted to explore spatial correlations in the number of individuals affected by COVID-19 in each province. Results: Based on the Moran index, a random spatial pattern with a Z-Score of 1.485 was identified in March 2019, whereas a clustered distribution of COVID-19 with a Z-Score of 3.039 was determined in February 2023. The distance-based spatial autocorrelation analysis revealed a positive value of the Moran index (0.136627) at a distance of 383.3 kilometers from Tehran, which points to positive spatial autocorrelation and a higher number of COVID-19 cases in nearby regions. Conversely, the Moran index assumed a negative value of 0.040246 at a distance of 726.6 kilometers from Tehran, which suggests that the number of pandemic cases decreased over distance from Tehran. Moreover, based on the results of the hot spot analysis, Tehran province was identified as a hot cluster with a higher prevalence of COVID-19 cases in that region. In contrast, Bushehr province was classified as a cold cluster with a lower prevalence of COVID-19 cases in comparison with the surrounding regions. These findings provide valuable insights into the spatial distribution and clustering of COVID-19 cases in Iran. The shift from a random spatial pattern in 2019 to clustered distribution in 2023 indicates that the pandemic spread rate increased over time. The positive spatial autocorrelation near Tehran highlights the role of proximity and population movement in the transmission of the virus. Furthermore, the identification of hot spots and cold spots in a country can inform targeted interventions and resource allocation to effectively manage and control the pandemic. Overall, this study demonstrates the value of spatial analysis in identifying the spatial distribution patterns and the dynamics of the COVID-19 pandemic in Iran. The integration of spatial analysis techniques with epidemiological data contributes to a better understanding of spatial-temporal patterns, facilitates effective public health responses and resource allocation strategies. These findings contribute to the growing body of knowledge on the spatial epidemiology of COVID-19 and can aid in informing future preparedness and response efforts in Iran and other regions that face similar challenges.

The Effect of Cycloplegia on Ocular Alignment and AC/A Ratio.

The present study sets out to investigate the effect of cyclopentolate-induced cycloplegia on distance and near deviation and the accommodative convergence/accommodation (AC/A) ratio. This prospective study was performed on 30 subjects. The inclusion criteria included a lack of any active ocular pathology and systemic diseases, no history of ocular surgery, and nonuse of various medications. Refraction, near and distance deviation were measured for all subjects, and the same examinations were repeated after the administration of two drops of cyclopentolate 1% to both eyes. The obtained data from 30 subjects, including 19 males, with a mean age of 22.53 1.74 years were analyzed. The mean SD of near deviation in dry and cycloplegic conditions were -6.9 8.1 and +6.4 9.1 prism diopters, respectively, which were statistically significant (P 0.001). Distance deviation in cycloplegic conditions demonstrated an average difference of 0.8 prism diopters, compared to dry conditions (P 0.001). AC/A ratios were 4.7 2.5 and 9.7 3.9 (Δ/D) in non-cycloplegic and cycloplegic conditions, respectively, which was a statistically significant difference (P 0.001). The multiple regression indicated that among all under study variables, refraction (B coefficient: -2.4; P 0.001) and near pre-cycloplegic deviation (B coefficient: 0.56; P 0.001) were significantly associated with post-cycloplegic near deviation. The results of this study indicated that cycloplegia causes a considerable esophoric shift in near deviation and a negligible esophoric shift in distance deviation. As a result, the AC/A ratio demonstrated a significant increase due to unequal changes in near and distance deviation.

Relationship between cross-sectional plane and corresponding morphology in an immiscible alloy powder with core-deviated structure

Immiscible alloy powders with core/shell structure have recently garnered considerable interest due to their excellent industrial performance. However, a frequently observed yet often overlooked feature is the presence of core-deviated structure in various cross-sectional planes of the powder. To date, limited research has been conducted on this structure and its origin, leaving the formation mechanism unclear. Gaining a comprehensive understanding of this mechanism is crucial for advancements in powder materials research. In this study, we first analyzed the solidification microstructures of Fe-68 wt.%Sn alloy powders, followed by a numerical analysis of airflow and internal temperature fields within a powder during the free-falling process. Our findings revealed that the average airflow velocity on the windward side is faster than that on the leeward side, causing the highest temperature point within the powder to shift towards the leeward side over time. This phenomenon is fundamentally linked to the formation of the core-deviated structure. Furthermore, we explored the relationship between cross-sectional planes and potential microstructures, demonstrating that the final observed structures are strongly influenced by the position and orientation of the cross-sectional plane. Additionally, the core deviation distance was theoretically predicted and found to be consistent with experimental results in Fe-68 wt.%Sn powders. This research provides valuable insights into the actual solidification process of immiscible alloy powders and contributes to the development of specialized structural materials.

The learning curve of a dynamic navigation system used in endodontic apical surgery

Background/purposeQuantitative in vitro research was conducted on the learning process of a dynamic navigation system. This study provides guidance for the promotion and application of dynamic navigation technology in the endodontic apical surgery field. Materials and methodsStandardized models were designed and 3D printed to form the approach operation of endodontic apical surgery. 6 clinicians with no experience in dynamic navigation performed the operation. The distance deviation tolerance was set as 0.6 mm, and the angle deviation tolerance was set as 5°. Fifteen mm deep approach operation was completed using dynamic navigation. Each operator performed 10 consecutive exercises on the models. The positioning deviation and operation time of each operator for each practice were recorded. Based on this, the learning curve of the dynamic navigation of every operator was mapped. The learning difficulty of dynamic navigation was evaluated. ResultsThe learning curves of all operators reached a stable level after the 7th practice, which can ensure that the distance and angle deviations are maintained within the deviation tolerances (0.6 mm, 5°). ConclusionOperators with no experience in dynamic navigation technology need practice to master dynamic navigation operations. For this navigation system, operators with no operational experience can master dynamic navigation operations after 7 exercises.

Effect of a calibration aid and the intraoral scanner on the registration of a partially edentulous maxilla: An in vitro study

Precise data are a prerequisite for accurately fitting restorations. Therefore, intraoral scanners have to be reliable. Data on differences between the same model of intraoral scanning systems are lacking. This in vitro study evaluated differences in the scanning accuracy of a partially edentulous maxilla between combinations of new intraoral scanners of a single model from the same manufacturer (Primescan; Dentsply Sirona) and several calibration aids. The in vitro reference model simulated a maxilla with 6 prepared teeth for a complete arch fixed partial denture. Five precision ceramic balls were used to detect dimensional deviation between the reference model and the scan. Distances were divided into 4 categories, from short distances between 2 neighboring precision balls to the cross-arch distance with the scan path comprising all 5 balls. For each combination of 4 new intraoral scanners and their respective calibration aids, 12 model registrations were generated. The data were statistically analyzed using ANOVA (α=.05). Distance deviations increased with increasing scan path length and were significantly affected by the covariates "scanner" (P≤.023) and, for 3 of 4 distance categories, the "calibration aid" (short, medium, and long distances: P≤.013). For short and medium distances, acceptable scanning results were achieved for all test groups. The largest deviation was 539µm for the cross-arch distance. Scanning accuracy depends on the scanner and the calibration aid used, in particular, for spans exceeding a single quadrant.

Clinical characteristics of acute acquired concomitant esotropia before and after the COVID-19 pandemic: a retrospective analysis.

This study aimed to observe the clinical characteristics of acute acquired concomitant esotropia (AACE) patients in recent five years and to examine the changes in the proportion of AACE cases before and after the COVID-19 pandemic. A retrospective study included 148 patients who underwent strabismus correction surgery for AACE between January 1, 2017, and December 31, 2021. The study analyzed the changing proportion of AACE cases before and after the COVID-19 pandemic and analyzed its clinical characteristics. Abnormalities in the worth 4 dot examination (both distance and near) were present in 134 cases (90.54%) before surgery, while 140 cases (94.59%) showed normal results after surgery. Near stereoacuity was present in 135 cases (91.22%). The near and distance deviations were (55.01 ± 18.77) PD and (57.30 ± 17.64) PD, respectively, and there was no significant difference between the two (p = 0.279). There were significant differences in the ratio of refractive status among different age groups (p < 0.001), while no statistically significant difference was observed in the ratio of refractive status for near deviation (p = 0.085) or distance deviation (p = 0.116). The proportion of AACE cases after the COVID-19 pandemic was significantly higher than that before the COVID-19 pandemic (p = 0.042). There was no statistically significant difference in the clinical characteristics between the two groups (p > 0.05). Myopia is the most common refractive status in AACE. More than half of patients had occupations that involved long hours of close work. The proportion of AACE cases increased significantly after the COVID-19 pandemic.

Positional Trueness with Different Titanium Base Bonding Techniques for Single Implant Crowns: In Vitro Evaluation of Model-Free Workflow Versus Additively Manufactured Models.

To compare the positional trueness of implant-crown bonding to titanium bases (Ti-bases) using different bonding protocols. A nonprecious alloy model with a single implant at the mandibular right first molar site was digitized, then a single implant crown was designed. The crown was milled, adhesively cemented on a Ti-base, and screw-retained on the implant in the master model to obtain a reference scan. Forty PMMA implant crowns were subtractively manufactured and allocated to one of four study groups (n = 10 crowns per group) based on the bonding protocol on Ti-bases: Group 1 = modelfree bonding; Group 2 = bonding on the master model (control); Group 3 = bonding on a model from an industrial-grade 3D printer (Prodways); Group 4 = bonding on a model from a conventional 3D printer (Asiga). To assess the positional trueness of crowns, the scans of crowns when on the model were superimposed over the reference scan. Median distance and angular deviations were analyzed using Kruskal-Wallis and Mann- Whitney tests (α = .05). Mesial and distal contacts of crowns were assessed by two independent clinicians. The control group (Group 2) resulted in the smallest distance deviations (0.30 ± 0.03 mm) compared to model-free (0.35 ± 0.02 mm; P = .002; Group 1) and conventional 3D printer (0.37 ± 0.01 mm; P = .001; Group 4) workflows. Buccolingual (P = .002) and mesiodistal (P = .01) angular deviations were higher in the conventional 3D printer group than in the control group (P = .002). Proximal contact assessments did not show any differences among groups. While bonding crowns to Ti-bases on a master model created with an industrial-grade 3D printer resulted in the highest positional trueness, model-free workflows had a similar positional trueness to those manufactured with a conventional 3D printer.

Fabrication Trueness, Intaglio Surface Adaptation, and Marginal Integrity of Resin-Based Onlay Restorations Fabricated by Additive and Subtractive Manufacturing.

To evaluate the fabrication trueness, intaglio surface adaptation, and marginal integrity of resin-based onlay restorations made via additive manufacturing (AM) or subtractive manufacturing (SM). An onlay restoration was designed (DentalCAD Galway 3.0) and saved as an STL file to generate a design STL file (DO-STL). Using this design, 45 onlays were fabricated either with AM (3D-printed resin for definitive [AM-D; Tera Harz TC-80DP] and interim [AM-I; Freeprint temp] restorations) or SM (composite resin, Tetric CAD) technologies. Onlays were scanned with an intraoral scanner (CEREC Primescan SW 5.2), and the scans were saved as test STL files (TO-STLs). For trueness evaluation, TO-STLs were superimposed over the DO-STL, and root mean square (RMS) values of overall and intaglio surfaces were measured (Geomagic Control X). For the intaglio surface adaptation and marginal integrity, a triple-scan protocol was performed. Kolmogorov-Smirnov, one-way ANOVA, and post-hoc Tukey honestly significant difference tests were used to analyze data (α = .05). RMS values of intaglio and overall surfaces, intaglio adaptation, and marginal integrity varied among test groups (P < .001). AM-D had the greatest overall surface RMS (P < .001), while SM had the greatest intaglio surface RMS (P < .001). SM had the highest average distance deviations for intaglio surface adaptation and marginal integrity, whereas AM-D had the lowest (P < .001). AM-D onlays showed lower overall trueness than AM-I onlays and SM definitive onlays. However, AM-D onlays presented high intaglio surface trueness, intaglio surface adaptation, and marginal integrity.

Accuracy of conventional impressions and digital scans for implant-supported fixed prostheses in maxillary free-ended partial edentulism: An in vitro study

ObjectivesTo evaluate the accuracy of conventional polyether impressions and digital scans produced by five intra-oral scanners (IOSs) in maxillary free-ended partial edentulism for long-span implant-supported prostheses. MethodsThis in vitro study involved the impression of a maxillary model with free-end partial edentulism, in which six implants were placed before digitization using a desktop scanner to generate a digital reference model. Conventional impressions (Impregum Penta Soft, 3M) and digital scans with five IOSs (Trios 3 and 4, 3Shape; Primescan, Dentsply-Sirona; CS 3600, Carestream Dental; and i-500, Medit) were obtained. Conventional impressions were digitized using the same desktop scanner. Each digital STL file of conventional or digital impressions was superimposed over the reference STL file to enable comparison. Trueness was assessed by calculating angles and distance deviations. For precision, dispersions of values around their means were also measured. ResultsThe mean distance deviation was significantly higher for conventional impressions (454.24 ± 334.70 µm) than for IOSs (ranging from 160.98 ± 204.48 µm to 255.56 ± 395.89 µm) (p < 0.001). The mean angular deviation was high with conventional impressions (1.82 ± 1.51°), intermediate with CS 3600 (1.38 ± 1.42°), Primescan (1.37 ± 2.54°) and Trios 4 (1.30 ± 0.64°) scanners, and lower with I500 (0.97 ± 0.75°) and Trios 3 (1.01 ± 0.85°) scanners (p < 0.001).The dispersion of distance values around their means was lowest with Trios 3 and i-500, followed by CS3600, Primescan, and Trios 4, respectively, and higher for conventional impressions (p < 0.001). The dispersion of angular values was smallest with i-500, Trios 3, and Trios 4 compared with other groups and was highest with Primescan (p < 0.001). ConclusionsWithin the limits of the current study, Trios 3 scanner exhibited the highest accuracy, followed by i-500, Trios 4, CS 3600, Primescan, and conventional impressions respectively. IOSs might be reliable for the fabrication of an implant-supported prosthesis. In vivo studies are required to confirm these findings. Clinical significancePassive adaptation of the implant-supported framework is a challenge when rehabilitating patients with maxillary free-end partial edentulism. While Conventional impressions remain a reliable and validated technique, but IOSs demonstrated higher accuracy, suitable for the fabrication of long-span implant-supported prostheses in partially edentulous arch.

Effect of refractive errors on the results of botulinum neurotoxin administration in patients with infantile esotropia.

To investigate the effect of refractive errors on the results of patients followed up with infantile esotropia (IE) and treated with botulinum neurotoxin (BNT) injection. The files of patients with IE who presented to the ophthalmology pediatric ophthalmology unit and underwent BNT injection into both medial rectus muscles between 2019 and 2021 were reviewed retrospectively. Sixty eyes of 30 patients were included in the study. Patients with additional systemic or ocular diseases and those with a history of ocular surgery were excluded. Distance and near deviations were measured (with the prism cover test or Krimsky method) before and at the first, third, and sixth months after BNT injection. In Group 1 (n = 20) with a spherical equivalent of + 2.0 diopters (D) or less, the mean near and distance deviation value was both 36.8 ± 12.7 prism diopter (PD) before injection. In Group 2 (n = 10) with a spherical equivalent of above + 2.0 D, the near deviation was measured as 35.0 ± 7.1 PD and distance deviation as 31.8 ± 7.9. At six months after BNT injection, the near and distance deviation values were 20.6 ± 12.3 and 20.6 ± 11.6 PD, respectively in Group 1 and 10.1 ± 10.3 and 8.8 ± 10.8 PD, respectively in Group 2. The change in deviation did not statistically significantly differ between the groups (p > 0.05), but the distance and near deviation values were lower in Group 2 at sixth months after BNT injection. BNT injection is a preferred method in IE. Higher hypermetropic values seem to increase the success of BNT injection.

Augmented Surgical Treatment in Patient with Partially Accomodative Esotropia

Introduction : Esotropia is a disorder of the position of the eyeball when the eye deviates inward. Surgical treatment is indicated when the eyes are not aligned with the glasses. We report a case of augmented surgical treatment in a partially accommodative esotropia patient.&#x0D; Case Illustration : A 18-year-old girl comes to the hospital with vision loss in both eyes since 1 year prior admission. Ocular alignment sinne correction was 300 (Figure 1) and cum correction was 150. Prism alternate cover test (PACT) showed deviation in sinne correction distance 60?BO dan near 50?BO, and deviation in cum correction distance 40?BO dan near 35?BO. Surgical formula with augmented surgery was (60?BO + 40?BO)/2 equal to 50?BO. Patient was diagnosed with Compositus Hypermetropia ODS + Partially Accommodative Esotropia. Patient underwent bilateral medial rectus recess surgery of 6 mm. Ophthalmology examination after 1 and 2.5 month surgery showed ocular alignment without spectacles showed microtropia and with spectacles showed orthotropia (Figure 2, 3a and 3b).&#x0D; Discussion : Various approaches can improve outcomes, including using different surgical formulas. Augmented surgery are the mean of deviation with and without surgery as the final deviation surgical formula.&#x0D; Conclusion : The amount of surgery in strabismus was based on the size of preoperative deviation. Augmented surgical treatment can be one of the choices to determine preoperative deviation in an esotropia patient.

Deep learning for automatic detection of cephalometric landmarks on lateral cephalometric radiographs using the Mask Region-based Convolutional Neural Network: a pilot study

ObjectiveWe examined the effectiveness and feasibility of the Mask Region-based Convolutional Neural Network (Mask R-CNN) for automatic detection of cephalometric landmarks on lateral cephalometric radiographs (LCRs). Study DesignIn total, 400 LCRs, each with 19 manually identified landmarks, were collected. Of this total, 320 images were randomly selected as the training dataset for Mask R-CNN, and the remaining 80 images were used for testing the automatic detection of the 19 cephalometric landmarks, for a total of 1520 landmarks. Detection rate, average error, and detection accuracy rate were calculated to assess Mask R-CNN performance. ResultsOf the 1520 landmarks, 1494 were detected, for a detection rate of 98.29%. The average error, or linear deviation distance between the detected points and the originally marked points of each detected landmark, ranged from 0.56 to 9.51 mm, with an average of 2.19 mm. For detection accuracy rate, 649 landmarks (43.44%) had a linear deviation distance less than 1mm, 1020 (68.27%) less than 2mm, and 1281 (85.74%) less than 4mm in deviation from the manually marked point. The average detection time was 1.48 seconds per image. ConclusionsDeep learning Mask R-CNN shows promise in enhancing cephalometric analysis by automating landmark detection on LCRs, addressing the limitations of manual analysis and demonstrating effectiveness and feasibility.

Novel complete-arch pillar system (CAPS) to register implant position and maxillomandibular relationship in one single visit

ObjectivesThis article presents a novel complete-arch pillar system (CAPS) to register implant position and maxillomandibular relationship in one single visit for implant-supported fixed complete dental prostheses (IFCDPs). Material and MethodsThe novel system presents a 3-unit toolset comprising intraoral scan bodies (ISBs), lateral pillar attachments (LPAs) and occlusal pillar attachments (OPAs). A 2-stage single visit workflow by an intraoral scanner (Trios 5) was introduced. The first stage “Screw-Scan-Done” was used to describe complete-arch intraoral implant scanning using LPAs. The second stage “Screw-Occlude-Done” involved virtual occlusal recording using OPAs. Two patients with one single edentulous arch were selected for this study. In the first patient, 6 bone level implants (Bone Level Tapered, Straumann) were placed in the edentulous maxilla at positions 12, 14, 16, 22, 24 and 26. In the second patient, 4 bone level implants (NobelActive CC, Nobel Biocare) were placed in the edentulous mandible at positions 32, 35, 42 and 45. A CAD-CAM procedure was initiated with the acquired IOS data to fabricate an interim IFCDP at the same day. Periapical radiographs were obtained of the implant-prosthetic connection of the definitive IFCDPs to verify the passive fit. Metrology software (Geomagic Qualify, 3D Systems – Matlab, Mathworks) was used to assess the implant analogs position in the 3D-printed casts used for fabricating the definitive IFCDPs. A quantitative occlusal relationship analysis was performed with IOS. ResultsRadiographic examination revealed no gaps at implant-prosthetic connection of the definitive IFCDPs. The 3D-printed casts showed an overall average distance deviation within the clinically acceptable range of errors of 150 µm. Quantitative occlusal relationship analysis with IOS showed well-distributed contacts. ConclusionWithin the limitations of this study, the following conclusions can be drawn:(1) A 3-unit toolset with ISBs, LPAs and OPAs allows to register the implant position and maxillomandibular relationship in one single visit;(2) the 2-stage clinical workflow with the CAPS system facilitates the IOS data acquisition for fabrication of an interim IFCDP at the same day;(3) a passive fit was demonstrated for the interim and the definitive IFCDPs. Clinical significanceThe CAPS system can help clinicians to register the implant position and the maxillomandibular relationship in one single visit for the fabrication of an IFCDP.

Brain Shift during Staged Deep Brain Stimulation for Movement Disorders

Introduction: Deep brain stimulation (DBS) is a routine neurosurgical procedure utilized to treat various movement disorders including Parkinson’s disease (PD), essential tremor (ET), and dystonia. Treatment efficacy is dependent on stereotactic accuracy of lead placement into the deep brain target of interest. However, brain shift attributed to pneumocephalus can introduce unpredictable inaccuracies during DBS lead placement. This study aimed to determine whether intracranial air is associated with brain shift in patients undergoing staged DBS surgery. Methods: We retrospectively evaluated 46 patients who underwent staged DBS surgery for PD, ET, and dystonia. Due to the staged nature of DBS surgery at our institution, the first electrode placement is used as a concrete fiducial marker for movement in the target location. Postoperative computed tomography (CT) images after the first electrode implantation, as well as preoperative, and postoperative CT images after the second electrode implantation were collected. Images were analyzed in stereotactic targeting software (BrainLab); intracranial air was manually segmented, and electrode shift was measured in the x, y, and z plane, as well as a Euclidian distance on each set of merged CT scans. A Pearson correlation analysis was used to determine the relationship between intracranial air and brain shift, and student’s t test was used to compare means between patients with and without radiographic evidence of intracranial air. Results: Thirty-six patients had pneumocephalus after the first electrode implantation, while 35 had pneumocephalus after the second electrode implantation. Accumulation of intracranial air following the first electrode implantation (4.49 ± 6.05 cm³) was significantly correlated with brain shift along the y axis (0.04 ± 0.35 mm; r (34) = 0.36; p = 0.03), as well as the Euclidean distance of deviation (0.57 ± 0.33 mm; r (34) = 0.33; p = 0.05) indicating statistically significant shift on the ipsilateral side. However, there was no significant correlation between intracranial air and brain shift following the second electrode implantation, suggesting contralateral shift is minimal. Furthermore, there was no significant difference in brain shift between patients with and without radiographic evidence of intracranial air following both electrode implantation surgeries. Conclusion: Despite observing volumes as high as 22.0 cm³ in patients with radiographic evidence of pneumocephalus, there was no significant difference in brain shift when compared to patients without pneumocephalus. Furthermore, the mean magnitude of brain shift was <1.0 mm regardless of whether pneumocephalus was presenting, suggesting that intracranial air accumulation may not produce clinical significant brain shift in our patients.

Factors Associated with Surgical Outcomes after Bilateral Lateral Rectus Recession in Children with Intermittent Exotropia

Backgroud: To analyze the factors associated with surgical outcomes after bilateral rectus recession (BLR) in children with intermittent exotropia (IXT). Methods: A retrospective study was performed on 125 patients who had all received preoperative patch treatment with a ≥1 year follow-up. The surgical outcomes were grouped as success (esodeviation ≤5 PD to exodeviation ≤10 PD) or failure (esodeviation &gt;5 PD or exodeviation &gt;10 PD) according to the angle of deviation at 1 year postoperatively. The patients’ magnitude of exodeviation, near and distant stereoacuity, and 3-mo patch responses were assessed. The factors associated with the surgical outcomes were determined using univariate and multivariate analyses. Results: Of the 125 patients, 102 (81.6%) and 23 (18.4%) were assigned to the success and failure groups, respectively. According to the univariate analysis, the absence of anisometropia, a smaller preoperative near exodeviation, a better near stereopsis, a smaller magnitude of deviation on day 1 postoperatively, and response to patching were significantly associated with surgical success for IXT after 1 year. In the multivariate analysis, distant esotropic deviation on day 1 postoperatively and response to patching were the factors affecting successful surgical outcomes. Conclusions: Esotropic distant deviation on day 1 postoperatively is a prognostic factor for favorable surgical outcomes. Preoperative patching could be a factor influencing surgical success in children with IXT.

Factors Predictive of Surgical Success in Medial Rectus Resection/Advancement for Consecutive Exotropia

Background and Objective: Consecutive exotropia after unilateral or bilateral medial rectus recession is a common clinical problem. One surgical intervention to address the misalignment involves isolating and reattaching healthy muscle to the globe. The purpose of this study was determining factors indicative of surgical success in medial rectus resection and advancement with non-adjustable sutures for consecutive exotropia.&#x0D; Methods: Through retrospective chart review, 118 patients were identified to have consecutive exotropia using billing codes from June 2016 to October 2020 at Indiana University Health. 60 of these patients who maintained adequate follow-up either underwent the above intervention (n = 49) or underwent resection only (n = 11). Exclusion criteria included lack of medial rectus procedure or poor postoperative documentation. Patient demographics and data were gathered, including preoperative and intraoperative measurements, final postoperative deviation, and whether additional surgeries were necessary. Chi-squared and two-sample t-tests were performed to analyze the effect of each parameter on surgical success, defined as distance deviation ≤ 10 prism diopters of esotropia or exotropia at final postoperative visit.&#x0D; Results: Smaller total intraoperative adjustment–resection plus advancement–was significantly associated with surgical success (p = 0.044). Additionally, smaller preoperative deviations were significantly associated with patients who underwent unilateral surgery (p = 0.0093 near and 0.0021 distance).&#x0D; Conclusion: Patients with smaller preoperative deviations tended to have better outcomes, and those patients tended to have unilateral surgery. It is unclear whether a smaller deviation might have led surgeons to select unilateral medial rectus surgery or if the smaller deviation itself is a predictor of success. Relatively limited time of follow-up is a limitation in this study, as there is well-documented postoperative drift of increasing exotropia over time. A larger cohort or randomized controlled trial may provide additional insight that could increase the percentage of successful outcomes with a single surgery.

Application of modified fusion convergence index in intermittent exotropia

Objective: To investigate a modified fusional convergence parameter-total convergence amplitude/distance angle and its relationship with exotropia control, stereoacuity, and other visual functions in intermittent exotropia. Methods: The cross-sectional study included children diagnosed with intermittent exotropia at the First Affiliated Hospital of Nanjing Medical University from August 2020 to June 2021. A modification was made by combining total convergence amplitude using synoptophore and distance angle at distance using prism bars to calculate total convergence amplitude/distance angle. Exotropia control at distance and near measured by Office-based Scale for Assessing Control was classified as good control (scale 0-1) and poor control (scale 2-5). Statistical analysis was performed using Spearman correlation analysis, Mann-Whitney U test, Fisher's exact test, χ2 test, logistic regression analysis, and mediation effect analysis. Results: The study included 212 patients, of which 105 (49.5%) were male and 107 (50.5%) were female. The median (interquartile range) age was 9.0 (8.0, 10.0) years. Of 211 cases, 201 (94.8%) had binocular fusional function, while 11 cases (5.2%) did not have binocular fusional function. Among patients with binocular fusional function, inverse correlation was observed between total convergence amplitude and exotropia control scores for both distance (r=-0.427, P<0.001) and near (r=-0.194, P=0.006). Total convergence amplitude/distance angle was an independent predictive factor for exotropia control at distance (OR=0.195; 95%CI, 0.060-0.630; P=0.006) and near (OR=0.252; 95%CI, 0.085-0.746; P=0.013). Stereoacuity at distance (OR=3.110; 95%CI, 1.311-7.379; P=0.010) and near (OR=2.780; 95%CI, 1.401-5.517; P=0.003) were also factors associated with distance exotropia control. Mediation analysis revealed that stereoacuity was not a mediating factor between the ratio and distance control (distance: P=0.066; near: P=0.181). In patients with ratio≥1.5 °/PD, all the 15 patients demonstrated good control. On the contrary, patients with ratio<1.5 °/PD showed worse exotropia control (distance: P=0.001; near: P=0.040) and larger angles of deviation (distance: P<0.001; near: P<0.001). Conclusion: The modified fusional ratio, total convergence amplitude/distance angle, combining synoptophore and prism bars, could be used to evaluate the severity of intermittent exotropia. A higher ratio may be associated with poorer exotropia control. Though it may also be associated with distance exotropia control, stereoacuity is not the mediating factor between the modified ratio and distance exotropia control.

A robust circle detector with regionalized radius aid

The detection of circles in geometric shapes is highly valued in computer vision and pattern recognition. Conventionally, the least-squares fitting is sensitive to occlusion or noise and prone to false circles. Therefore, this paper proposes a novel algorithm for robust circle detection using the least-squares fitting method combined with regionalized radius aid on the arc and chord lengths. To reduce edge noise impact, we present an edge pruning method to prune non-curve edge branch ports. Furthermore, we extract arcs based on the inflection points and sharp corners of the approximate line segment. Next, curves that belong to the arcs obtain circle parameters according to the regionalized radius aided the least-squares method. Then, valid circles are obtained by considering two distance deviations to verify the candidate circles. Finally, valid arcs that belong to the same circle are combined and refitted, wherein the most representative arc is used as the basis for the refitting of all arcs. All experiments are conducted on real images from four publicly diverse datasets (one of them is the one we built). The detection results are compared with those of representative state-of-the-art algorithms, and the proposed algorithm has several advantages based on the comparison results: more robust to noise, effective rejection of false circles, and better performance.