Mean Volume Difference Research Articles

Subject-Level Segmentation Precision Weights for Volumetric Studies Involving Label Fusion.

In neuroimaging research, volumetric data contribute valuable information for understanding brain changes during both healthy aging and pathological processes. Extracting these measures from images requires segmenting the regions of interest (ROIs), and many popular methods accomplish this by fusing labels from multiple expert-segmented images called atlases. However, post-segmentation, current practices typically treat each subject's measurement equally without incorporating any information about variation in their segmentation precision. This naïve approach hinders comparing ROI volumes between different samples to identify associations between tissue volume and disease or phenotype. We propose a novel method that estimates the variance of the measured ROI volume for each subject due to the multi-atlas segmentation procedure. We demonstrate in real data that weighting by these estimates markedly improves the power to detect a mean difference in hippocampal volume between controls and subjects with mild cognitive impairment or Alzheimer's disease.

Sleep quality and risk of obstructive sleep apnea among breast cancer survivors with and without lymphedema.

Breast cancer survivors (BCSs) tend to have sleep disturbances such as obstructive sleep apnea (OSA). However, limited evidence exists on the role of breast cancer-related lymphedema (BCRL) in sleep disturbances and OSA. Therefore, this study aimed to investigate the quality of sleep (QoS) and OSA risk among women with and without BCRL. The quality of life (QoL) was evaluated using the SF-12 and EORTC-QLQ C-30 questionnaires, while their sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. The STOP-bang questionnaire (SBQ) was utilized to quantify OSA risk. Sleepiness was assessed using the Epworth Sleepiness Scale (ESS). Also, neck and waist circumference and the excessive volume in the affected limb were measured using a tape measure. The statistical analyses were performed using the SPSS 21.0 software. Seventy-one women with BCRL and 84 BCS without lymphedema were included. The comparison of PSQI, SBQ, ESS, SF-12, and EORTC QLQ-C30 questionnaires exhibited no significant difference between these two groups. The overnight snoring and average neck circumference were significantly higher in the BCRL group than in the control. The BCRL stage significantly correlated with neck circumference and SBQ total score. Additionally, the mean volume difference indicated a significant correlation with the ESS total score and both physical and mental summary components of the SF-12 questionnaire. The prevalence of sleep disturbances among BCSs with and without BCRL is high. Women with advanced stages of BCRL might be at high risk for OSA. Therefore clinical evaluation of BMI, neck circumference, and, snoring overnight should be emphasized among this population.

Validation of SynthSeg segmentation performance on CT using paired MRI from radiotherapy patients

Introduction:Manual segmentation of medical images is labor intensive and especially challenging for images with poor contrast or resolution. The presence of disease exacerbates this further, increasing the need for an automated solution. To this extent, SynthSeg is a robust deep learning model designed for automatic brain segmentation across various contrasts and resolutions. This study validates the SynthSeg robust brain segmentation model on computed tomography (CT), using a multi-center dataset. Methods:An open access dataset of 260 paired CT and magnetic resonance imaging (MRI) from radiotherapy patients treated in 5 centers was collected. Brain segmentations from CT and MRI were obtained with SynthSeg model, a component of the Freesurfer imaging suite. These segmentations were compared and evaluated using Dice scores and Hausdorff 95 distance (HD95), treating MRI-based segmentations as the ground truth. Brain regions that failed to meet performance criteria were excluded based on automated quality control (QC) scores. Results:Dice scores indicate a median overlap of 0.76 (IQR: 0.65-0.83). The mean volume difference is 7.79% (CI: 6.41%–9.18%), with CT segmentations typically smaller than MRI-based. The median HD95 is 2.95 mm (IQR: 1.73-5.39). QC score based thresholding improves median dice by 0.1 and median HD95 by 0.05 mm. Morphological differences related to sex and age, as detected by MRI, were also replicated with CT, with an approximate 17% difference between the CT and MRI results for sex and 10% difference between the results for age. Conclusion:SynthSeg can be utilized for CT-based automatic brain segmentation, but only in applications where precision is not essential. CT performance is lower than MRI based on the integrated QC scores, but low-quality segmentations can be excluded with QC-based thresholding. Additionally, performing CT-based neuroanatomical studies is encouraged, as the results show correlations in sex- and age-based analyses similar to those found with MRI.

Evaluating brain volume segmentation accuracy and reliability of FreeSurfer and Neurophet AQUA at variations in MRI magnetic field strengths.

We aimed to compare the accuracy and reliability of two segmentation tools for magnetic resonance (MR) volumetry (FreeSurfer and Neurophet AQUA) at two magnetic field strengths (1.5T and 3T). We included 101 patients for the 1.5T-3T dataset and 112 for the 3T-3T dataset from three hospitals and five open-source datasets. The mean volume difference and average volume difference percentage with the change in magnetic field strength were compared between the methods. The hippocampus volume was larger with FreeSurfer than the Neurophet AQUA. In most brain regions, the Neurophet AQUA yielded a smaller average volume difference percentage (all < 10%) than FreeSurfer (all > 10%). The Neurophet AQUA exhibited more stable connectivity and regularity of the segmented components. Regarding volume, the Neurophet AQUA had effect sizes and ICCs comparable to those of FreeSurfer across the magnetic field strengths. With FreeSurfer, the original volume difference was small, whereas the average volume difference percentage was small with the Neurophet AQUA. Image segmentation took 1h with FreeSurfer and 5min with the Neurophet AQUA. When choosing an automatic segmentation method, the differences in image processing time and volume variability due to changes in the magnetic field strength of these methods should be considered.

Precise ablation zone segmentation on CT images after liver cancer ablation using semi-automatic CNN-based segmentation.

Ablation zone segmentation in contrast-enhanced computed tomography (CECT) images enables the quantitative assessment of treatment success in the ablation of liver lesions. However, fully automatic liver ablation zone segmentation in CT images still remains challenging, such as low accuracy and time-consuming manual refinement of the incorrectregions. Therefore, in this study, we developed a semi-automatic technique to address the remaining drawbacks and improve the accuracy of the liver ablation zone segmentation in the CTimages. Our approach uses a combination of a CNN-based automatic segmentation method and an interactive CNN-based segmentation method. First, automatic segmentation is applied for coarse ablation zone segmentation in the whole CT image. Human experts then visually validate the segmentation results. If there are errors in the coarse segmentation, local corrections can be performed on each slice via an interactive CNN-based segmentation method. The models were trained and the proposed method was evaluated using two internal datasets of post-interventional CECT images ( = 22, = 145; 62 patients in total) and then further tested using an external benchmark dataset ( = 12; 10 patients). To evaluate the accuracy of the proposed approach, we used Dice similarity coefficient (DSC), average symmetric surface distance (ASSD), Hausdorff distance (HD), and volume difference (VD). The quantitative evaluation results show that the proposed approach obtained mean DSC, ASSD, HD, and VD scores of 94.0%, 0.4 mm, 8.4 mm, 0.02, respectively, on the internal dataset, and 87.8%, 0.9 mm, 9.5 mm, and -0.03, respectively, on the benchmark dataset. We also compared the performance of the proposed approach to that of five well-known segmentation methods; the proposed semi-automatic method achieved state-of-the-art performance on ablation segmentation accuracy, and on average, 2 min are required to correct the segmentation. Furthermore, we found that the accuracy of the proposed method on the benchmark dataset is comparable to that of manual segmentation by human experts ( = 0.55, -test). The proposed semi-automatic CNN-based segmentation method can be used to effectively segment the ablation zones, increasing the value of CECT for an assessment of treatment success. For reproducibility, the trained models, source code, and demonstration tool are publicly available at https://github.com/lqanh11/Interactive_AblationZone_Segmentation.

Comparative evaluation of clinical efficacy and volumetric changes in pulpectomized primary molars using hand K-file, ProTaper rotary file, and Kedo-SG blue file: an in-vitro cone beam computed tomography analysis.

The accomplishment of a successful pulpectomy depends on multiple factors that involve targeted removal of the causative irritants and soft and hard tissue debris by mechanical and chemical means. Compare and evaluate the efficacy of canal preparation and volumetric filling using conventional files and two rotary file systems using cone beam computed tomography (CBCT). Thirty freshly extracted human primary second molars were randomly divided into three groups of 10 teeth each. After access opening and working length determination, pre-operative volume analysis was done using CBCT. The canals were then instrumented by either hand K-files, ProTaper rotary files or Kedo-SG Blue rotary files. Post-operative volume analysis was performed using CBCT. All the canals were obturated using Metapex and scanned again using CBCT. Mean values of the pre- and post-operative canal volumes were analyzed using one-way Analysis of Variance (ANOVA). Inter- and intra-group volumetric changes were analyzed statistically using a post hoc test. The mean difference in volume after canal preparation and obturation was the highest in the Kedo-SG Blue group, followed by the ProTaper group and the least in the hand K group (p = 0.001). Inter-group comparison showed statistically significant differences between the hand K group and ProTaper group (p = 0.001), the ProTaper group and Kedo-SG Blue group (p = 0.001), and the hand-K group and Kedo-SG Blue group (p = 0.02). The volume of preparation and obturation was the highest using Kedo-SG Blue, followed by the ProTaper file systems.

Abstract PO5-22-03: Influence of the surgical clip concerning the dose and volume of irradiated surrounding tissues including lung and heart in the planning of radiotherapy boost with conservative breast surgery with and without oncoplasty

Abstract Introduction: Patients with the highest risk of breast cancer undergoing conservative surgery receive an additional boost dose of radiotherapy in the tumor bed during treatment planning, which is known to bring benefits in local control. Objectives: To evaluate the influence of the surgical clip concerning the volume of surrounding tissues irradiated during radiotherapy, in patients submitted to conservative breast surgery with and without oncoplasty. Materials/Methods. The analyzed variables were defined as: the volume of the boost (V100 Boost) and breast tissue (V100 Breast) that received 100% of the prescribed dose during the radiotherapy planning and the volume of the heart (V40 Heart) and lung (V40 Lung) that received 40% of the prescribed dose during the boost phase in patients undergoing treatment with breast conservation. The variables were compared about the insertion or not of the surgical clip and the influence of oncoplastic surgery on the volume of irradiated tissues of the breast, boost, heart and lung during radiotherapy planning. Student's t-test (95%CI; p&amp;lt; 0.05) was used to compare mean volumes as a function of the presence or not of surgical clips and oncoplastic surgery. Results: Retrospective study included 183 women with breast cancer who underwent treatment with conservative breast surgery and radiotherapy of the whole breast, followed by sequential boost, between January 2011 and January 2021. Boost, breast, heart, and lung volumes were evaluated during planning for conformational radiotherapy. The results showed a significant difference between the average boost volumes when the patient was clipped. The average boost volume that received 100% of the prescribed dose was V100 Boost=244.22cm³ (SD±158) in the absence of the clip. In the presence of 1 or 2 clips, this average was V100 Boost= 94.87cm³ (SD±37) and with 3 or more clips it was V100 Boost= 96.99cm³ (SD±39) (p&amp;lt; 0.001). There was also a significant difference in mean breast volumes that received 100% of the prescribed dose. In the absence of the clip, the V100 Breast=373.16 cm³ (SD±222) and when 1 or 2 clips were present, the V100 Breast=235.28 cm³ (SD±125) (p=0.01). The analyzes of the mean volumes of the heart (V40 Heart) and lung (V40 Lung) that received 40% of the prescribed boost dose were not statistically significant, regardless of the presence and number of clips. For the oncoplasty group, there was no statistical difference between the means of boost, breast, heart and lung volumes. Conclusion: The presence of the surgical clip reduced the volume of the boost and the breast that received 100% of the dose in the radiotherapy planning. The volume of the boost (V100 Boost), which received 100% of the dose prescribed during radiotherapy planning, was smaller in patients with a surgical clip, as was the volume of irradiated breast tissue (V100 Breast) in clipped patients. The volume of irradiated tissue in the heart (V40 Heart) and lung (V40 Lung) that received 40% of the prescribed dose during the boost phase in radiotherapy planning did not suffer statistical differences in insertion or not of the surgical clip. Oncoplastic surgery and the presence of surgical clips did not influence the volumes of irradiated boost, breast, heart and lung tissues during the radiotherapy planning of patients undergoing conservative surgical treatment of the breast. Table: Means of boost, breast, heart and lung irradiated volumes according to the presence or absence of clips and oncoplastic surgery Table. Means of boost, breast, heart and lung irradiated volumes according to the presence or absence of clips and oncoplasty surgery Variable (cm3) Clip p valor Oncoplasty p valor With Without With Without Means Means Means Means V100% Boost 94 244 &amp;lt; 0,001 102 118 0,906 V100% Breast 235 373 0,01 271 272 0,816 V40% Heart 1,10 4,52 0,33 1,96 1,39 0,903 V40% Lung 56,66 56,10 0,93 51,63 52,53 0,796 Citation Format: Nilceana Freitas, Priscila Watanabe, Jean Paiva, Carolina Bezerril, Marcelo Valentim, Thais Gontijo, Flavia Araujo, Ruffo Freitas-Junior. Influence of the surgical clip concerning the dose and volume of irradiated surrounding tissues including lung and heart in the planning of radiotherapy boost with conservative breast surgery with and without oncoplasty [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-22-03.

Presurgical Virtual Planning and Intraoperative Navigation with 3D-Preformed Mesh: A New Protocol for Primary Orbital Fracture Reconstruction.

This pilot study aims to evaluate the feasibility and effectiveness of computer-assisted surgery protocol with 3D-preformed orbital titanium mesh (3D-POTM), using presurgical virtual planning and intraoperative navigation in primary inferomedial orbital fracture reconstruction. Between March 2021 and March 2023, perioperative data of patients undergoing surgery for unilateral inferomedial orbital fracture treated with 3D-POTM were analyzed. Presurgical virtual planning with a Standard Triangle Language file of preformed mesh was conducted using the mirrored unaffected contralateral side as a reference, and intraoperative navigation was used. The reconstruction accuracy was determined by: correspondence between postoperative reconstruction mesh position with presurgical virtual planning and difference among the reconstructed and the unaffected orbital volume. Pre- and postoperative diplopia and enophthalmos were assessed. Twenty-six patients were included. Isolated orbital floor fracture was reported in 14 (53.8%) patients, meanwhile medial wall and floor one in 12 (46.1%) cases. The mean difference between final plate position and ideal digital plan was 0.692 mm (95% CI: 0.601-0.783). The mean volume difference between reconstructed and unaffected orbit was 1.02 mL (95% CI: 0.451-1.589). Preoperative diplopia was settled out in all cases and enophthalmos in 19 (76.2%) of 21 patients. The proposed protocol is an adaptable and reliable workflow for the early treatment of inferomedial orbital fractures. It enables precise preoperative planning and intraoperative procedures, mitigating pitfalls and complications, and delivering excellent reconstruction, all while maintaining reasonable costs and commitment times.

Volumetric Analysis of Various Pediatric Rotary Files in the Preparation of Primary Root Canals Using Cone-beam Computed Tomography.

This study was planned to evaluate and compare the cleaning efficacy of three pediatric rotary files with the standard Protaper adult file system in primary teeth using cone-beam computed tomography (CBCT). A total of 40 extracted deciduous second molars, with palatal/mesial roots having at least two-thirds of root length and an intact furcation area, were distributed randomly among four groups, with each group containing 10 teeth. Canal preparation of group I (Pro AF Baby Gold), group II (Kedo SG Blue), group III (Prime Pedo), and group IV (Protaper) was done. Pre- and postoperative CBCT images were taken. The volumetric changes of the root canals were assessed and subjected to statistical analysis using Statistical Package for the Social Sciences (SPSS) version 16 and R Studio 3.1.1. Volumetric changes within the groups were analyzed using paired t-tests and between the groups using analysis of variance (ANOVA). The comparison of mean volume difference between groups using ANOVA was statistically significant with F = 4.467, p = 0.002. A Tukey post hoc test revealed that group IV was statistically significant compared with groups I (p = 0.033) and III (p = 0.008) but was not statistically significant with group II (p = 0.170). There was no statistically significant difference in volumetric changes within the three pediatric rotary file systems. Protaper removed more dentin than all the pediatric rotary files, but it was not statistically significant over Kedo SG Blue. Among the pediatric rotary files, Kedo SG Blue removed more dentin than Pro AF Baby Gold and Prime Pedo, but they were not statistically significant. Nainer Chidambaram JV, Jayaprakash J, Arangannal P. Volumetric Analysis of Various Pediatric Rotary Files in the Preparation of Primary Root Canals Using Cone-beam Computed Tomography. Int J Clin Pediatr Dent 2024;17(1):15-20.

Automatic thoracic aorta calcium quantification using deep learning in non-contrast ECG-gated CT images

Thoracic aorta calcium (TAC) can be assessed from cardiac computed tomography (CT) studies to improve cardiovascular risk prediction. The aim of this study was to develop a fully automatic system to detect TAC and to evaluate its performance for classifying the patients into four TAC risk categories. The method started by segmenting the thoracic aorta, combining three UNets trained with axial, sagittal and coronal CT images. Afterwards, the surrounding lesion candidates were classified using three combined convolutional neural networks (CNNs) trained with orthogonal patches. Image datasets included 1190 non-enhanced ECG-gated cardiac CT studies from a cohort of cardiovascular patients (age 57 ± 9 years, 80% men, 65% TAC > 0). In the test set (N = 119), the combination of UNets was able to successfully segment the thoracic aorta with a mean volume difference of 0.3 ± 11.7 ml (<6%) and a median Dice coefficient of 0.947. The combined CNNs accurately classified the lesion candidates and 87% of the patients (N = 104) were accurately placed in their corresponding risk categories (Kappa = 0.826, ICC = 0.9915). TAC measurement can be estimated automatically from cardiac CT images using UNets to isolate the thoracic aorta and CNNs to classify calcified lesions.

Predesigned chimeric deep inferior epigastric perforator and inguinal lymph node flap for combined breast and lymphedema reconstruction: A comprehensive algorithmic approach

The combined use of a deep inferior epigastric perforator (DIEP) flap coupled with vascularized inguinal lymph nodes (VILNs) for simultaneous breast and lymphedema reconstruction has already been well established, and promising results have been reported. However, a standardized approach for the planning and shaping of this combined flap is still lacking. We aimed to propose a comprehensive algorithmic approach for delayed unilateral breast and lymphedema reconstruction using a predesigned abdominal flap associated with inguinal lymph node transfer. We present in detail the preoperative measurements and surgical technique of the chimeric flap, which combines a predesigned DIEP template and a preselected inguinal lymph node flap, based on the preoperative computed tomography angiography and SPEC-CT findings, respectively; four different flap types are described according to the location of the pedicles of the two flap components. Our results of a series of 34 consecutive female patients with unilateral mastectomy and arm lymphedema, who underwent this combined predesigned reconstructive procedure, are retrospectively analyzed and reported. We recorded a high survival rate of the chimeric flaps in our series, with only one case of partial ischemic loss of a DIEP skin island. In the majority of our patients, the pedicles of the combined flaps were located in opposite positions. After a mean 35-month follow-up, we recorded a 47% mean volume difference reduction of the lymphedematous compared to the unaffected arm; no donor-site lymphedema was documented. Self-evaluation questionnaires showed high patient satisfaction rates regarding breast reconstruction. This algorithmic approach provides standardized guidance for accurate design and transfer of the DIEP-VILN chimeric flap while achieving highly satisfactory outcomes for both breast and lymphedema reconstruction.

3-D Contrast-Enhanced Fusion Ultrasound for Accurate Volume Assessment of Vessel Lumen and Plaque in Carotid Artery Disease as Compared With Computed Tomography Angiography

ObjectiveThree-dimensional contrast-enhanced fusion ultrasound (3D-CEFUS) of atherosclerotic carotid arteries provides spatial visualisation of the vessel lumen, creating a lumenography. As in 3D computed tomography angiography (3D-CTA), 3D-CEFUS outlines the contrast-filled lumen. Plaque and vessel contours are distinguished in 3D-CEFUS, allowing plaque volume quantification as a valid estimate of carotid plaque burden. 3D-CEFUS is unproven in inter-modality studies, vindicating the assessment of 3D-CEFUS applicability and comparing 3D-CEFUS and 3D-CTA lumenography as a proof-of-concept study. MethodsUsing an ultrasound system with magnetic tracking, a linear array transducer, and SonoVue contrast agent generated 3D-CEFUS acquisitions by spatial stitching of serial 2D images. From 3D-CEFUS and 3D-CTA imaging, the atherosclerotic carotid arteries were reconstructed with lumenography in an offline software programme for lumen and plaque volume quantification. Bland-Altman analysis was used for inter-image-modality agreement. ResultsThe study included 39 carotid arteries. Mean lumen and plaque volume in 3D-CEFUS were 0.63 cm3 (SD 0.26) and 0.62 cm3 (SD 0.26), respectively. Lumen volume differences between 3D-CEFUS and 3D-CTA were non-significant, with mean difference of 0.01 cm3 (SD 0.02, p = .26) and limits of agreement range (LoA-range) of ±0.11 cm3. Mean plaque volume difference was -0.12 cm3 (SD 0.19, p = .006) with LoA-range of ±0.39 cm3. ConclusionStrong agreement in lumenography between 3D-CEFUS and 3D-CTA was found. The inter-image-modality difference in plaque volumes was substantial due to challenging vessel wall definition in 3D-CTA. 3D-CEFUS is viable in quantifying carotid plaque volume burden and can potentially monitor plaque development over time.

Comparative evaluation of volumetric changes between two pediatric rotary files (Kedo-S plus, Kedo-SG blue) and manual files (hand K-files) during canal preparation of primary mandibular molars: an in-vitro nano-CT analysis.

Pediatric endodontics has become popular due to advancements in cleaning, shaping and irrigation systems, resulting in faster and effective removal of infected pulp, saving time, and creating a pathogen-free environment. The patented rotary file system, Kedo-S, designed for primary teeth, introduced a single file generation for efficient pulp therapy. However, there are currently no studies assessing canal preparation in primary mandibular molars using nano-CT (computed Tomography). To evaluate the volumetric changes of two recently introduced pediatric rotary file systems in comparison with conventional hand file systems in primary mandibular molar using an ultra-high resolution nano-CT. This in-vitro study was performed in extracted primary mandibular molar based on certain inclusion and exclusion criteria. Samples were prepared and working length was determined before the pre-operative scan using a high resolution nano-CT device (SkyScan 2214, Bruker, Kontich, Belgium). A single well-experienced pediatric dentist prepared the canals using three file systems: Kedo-S plus, Kedo-SG blue and Hand K-files. A post-operative scan was performed similar to pre-operative scan. Image reconstruction was performed with NRecon software for 3D volumetric visualization and analysis of the root canals. Kedo-SG blue file systems had the highest mean difference in the canal volume (8.85%). Hand K-files had the least difference at (1.24%) of canal volume. Kedo-S plus file system had a mean canal volume difference (6.14%) which is closer to hand K-files. Rotary file systems resulted in a significant enlargement of canals compared to hand files.

WTP8.9 3D volume assessment as an objective tool in breast asymmetry management

Abstract Background The normal symmetrical appearance of the breast is a vital. It can be psychologically distressing to patients and affects their body perception when these differences are obvious. The goal of breast surgeons is minimising these differences to make them more acceptable to patients. Methods This study was done on 20 females seeking breast asymmetry correction. Age ranged from 18 to 45 years (mean age: 30.4). All patients had volumetric breast assessment using a (3D) imaging system (3D LifeViz®, Quantificare system). The first 10 patients were chosen randomly for breast (MRI) volumetry to confirm the results of the 3D system. The patients were managed with different single-stage surgical procedures depending upon the objective assessment of the volume difference between their breasts. Results Breast volume assessment using the 3D camera was done in all 20 patients pre-operatively 30 and postoperatively. The preoperative mean volume difference was 159.45 cm3, and the postoperative mean difference was 16.75 cm3, with an overall reduction in mean volume difference of 89.5%. Breast MRI volumetry was done for 10 randomly chosen patients to confirm the results and ranged between 3 and 12 cm3 (average 7.1 cm3) on the right and 0 and 15 cm3 (average 6.3 cm3) on the left. Comparing the 3D camera and MRI in assessing breast volume difference showed that the difference ranged between 1 and 5 cm3 with an average of 2.4 cm3, which was not statistically significant. Conclusion The 3D technology is useful objective tool to augment the surgeons’ experience. It helped to achieve an 84.57% reduction in volume difference in managing asymmetry with single-stage procedure.

A comparative evaluation of mechanical wear of adhesives used for bonded retainers that underwent brushing for 1hour under 36mm of linear action, using computer-aided 3D scan-an in vitro study.

The aim of the present study was to comparatively evaluate the mechanical wear of adhesives used in bonded retainers. Eighty mandibular acrylic teeth were included in the study that were divided into 4 different groups based upon the composite used. Each acrylic tooth was bonded with a retainer wire and composite of their respective group (Heliosit, Restofill, Tetric-N-flow, and Filtek Z350 XT). These bonded acrylic teeth were subjected to 3D scan in order to evaluate the volume and surface area of the composite. The 3D scans were recorded using MEDIT 3D scanner. After evaluating, the samples were subjected to brushing with the aid of a custom-made brushing simulator using a toothbrush with soft bristles and toothpaste slurry. The samples were subjected to 1hr of brushing. These samples were again subjected to 3D scans to evaluate (post-test volume and surface area) and underwent statistical analysis. The results showed the Heliosit group exhibited the highest mean volume (1.76mm3) and surface area (4.81mm2) difference between the pre-test and post-test values whereas the least mean volume difference (1.10mm3) and surface area difference (3.21mm2) were seen in the Tetric-N-flow group. All the four composites underwent change in the mean surface area and volume after being subjected to brushing, suggesting that the composites routinely used for bonding fixed bonded lingual retainers are subjected to changes due to abrasion. The Heliosit group, which showed least filler loading among the 4 composites, exhibited least resistance to wear, whereas the Tetric-N-flow group which had highest filler loading among the composites exhibited highest resistance to wear. The most crucial phase during orthodontic treatment is the retention phase. This phase is responsible for the long-term results of the treatment. The retainers that are placed in the oral cavity are subjected to changes due to oral environment, chemical changes, and mechanical changes. These changes have a direct effect on the retainers, which tend to alter their properties. Thus, the effects of these changes are to be studied thoroughly.

Three-dimensional ultrasound to investigate synovitis in first carpometacarpal osteoarthritis: A feasibility study.

Synovitis is one of the defining characteristics of osteoarthritis (OA) in the carpometacarpal (CMC1) joint of the thumb. Quantitative characterization of synovial volume is important for furthering our understanding of CMC1 OA disease progression, treatment response, and monitoring strategies. In previous studies, three-dimensional ultrasound (3-D US) has demonstrated the feasibility of being a point-of-care system for monitoring knee OA. However, 3-D US has not been tested on the smaller joints of the hand, which presents unique physiological and imaging challenges. To develop and validate a novel application of 3-D US to monitor soft-tissue characteristics of OA in a CMC1 OA patient population compared to the current gold standard, magnetic resonance imaging (MRI). A motorized submerged transducer moving assembly was designed for this device specifically for imaging the joints of the hands and wrist. The device used a linear 3-D scanning approach, where a 14L5 2-D transducer was translated over the region of interest. Two imaging phantoms were used to test the linear and volumetric measurement accuracy of the 3-D US device. To evaluate the accuracy of the reconstructed 3-D US geometry, a multilayer monofilament string-grid phantom (10mm square grid) was scanned. To validate the volumetric measurement capabilities of the system, a simulated synovial tissue phantom with an embedded synovial effusion was fabricated and imaged. Ten CMC1 OA patients were imaged by our 3-D US and a 3.0 T MRI system to compare synovial volumes. The synovial volumes were manually segmented by two raters on the 2D slices of the 3D US reconstruction and MR images, to assess the accuracy and precision of the device for determining synovial tissue volumes. The Standard Error of Measurement and Minimal Detectable Change was used to assess the precision and sensitivity of the volume measurements. Paired sample t-tests were used to assess statistical significance. Additionally, rater reliability was assessed using Intra-Class Correlation (ICC) coefficients. The largest percent difference observed between the known physical volume of synovial extrusion in the phantom and the volume measured by our 3D US was 1.1% (p-value=0.03). The mean volume difference between the 3-D US and the gold standard MRI was 1.78% (p-value=0.48). The 3-D US synovial tissue volume measurements had a Standard Error Measurement (SEm ) of 11.21mm3 and a Minimal Detectible Change (MDC) of 31.06mm3 , while the MRI synovial tissue volume measurements had an SEM of 16.82mm3 and an MDC of 46.63mm3 . Excellent inter- and intra-rater reliability (ICCs=0.94-0.99) observed across all imaging modalities and raters. Our results indicate the feasibility of applying 3-D US technology to provide accurate and precise CMC1 synovial tissue volume measurements, similar to MRI volume measurements. Lower MDC and SEm values for 3-D US volume measurements indicate that it is a precise measurement tool to assess synovial volume and that it is sensitive to variation between volume segmentations. The application of this imaging technique to monitor OA pathogenesis and treatment response over time at the patient's bedside should be thoroughly investigated in future studies.

Hinge craniotomy versus standard decompressive hemicraniectomy: an experimental preclinical comparative study.

Decompressive craniectomy (DC) is the most common surgical procedure to manage increased intracranial pressure (ICP). Hinge craniotomy (HC), which consists of fixing the bone operculum with a pivot, is an alternative method conceived to avoid some DC-related complications; nonetheless, it is debated whether it can provide enough volume expansion. In this study, we aimed to analyze the volume and ICP obtained with HC using an experimental cadaver-based preclinical model and compare the results to baseline and DC. Baseline conditions, HC, and DC were compared on both sides of five anatomical specimens. Volume and ICP values were measured with a custom-made system. Local polynomial regression was used to investigate volume differences. The area of the bone opercula resulting from measurements was 115.55 cm2; the mean supratentorial volume was 955 mL. HC led to intermediate results compared to baseline and DC. At an ICP of 50 mmHg, HC offers 130 mL extra space but 172 mL less than a DC. Based on local polynomial regression, the mean volume difference between HC and the standard craniotomy was 10%; 14% between DC and HC; both are higher than the volume of brain herniation reported in the literature in the clinical setting. The volume leading to an ICP of 50 mmHg at baseline was less than the volume needed to reach an ICP of 20 mmHg after HC (10.05% and 14.95% from baseline, respectively). These data confirm the efficacy of HC in providing sufficient volume expansion. HC is a valid intermediate alternative in case of potentially evolutionary lesions and non-massive edema, especially in developing countries.

Anatomic risk factors for arthroscopic Bankart repair failure: A case-control study comparing failure and non-failure groups in an Asian population

IntroductionPost-arthroscopic Bankart repair failure/re-dislocation rates are influenced by several risk factors, including anatomic defects. There is limited evidence on the role of anatomic defects, especially for Hill-Sachs size in on-track lesions. This study aimed to assess glenoid bone loss, Hill-Sachs lesion and labral tear size and evaluate their contribution to post-operative instability after a primary repair. Material and methodsAcross 169 patients with on-track Bankart lesions who underwent primary arthroscopic Bankart repair from 2010 to 2015, this study matched 14 failure with 14 non-failure cases based on age/gender. Patient demographics, pre-operative radiological parameters (including size of glenoid bone loss and Hill-Sachs lesion) and labral tear size were compared between the failure and non-failure groups. ResultAll patients were male with a mean age of 21.01 ± 4.97. Significantly greater glenoid bone loss (p = 0.024) and labral tear size (p = 0.039) were found in the failure group. However, there was no significant difference in mean volume of Hill-Sachs lesion between the two groups (p = 0.739). ConclusionExtensive glenoid bone loss and labral tears are risk factors for post-arthroscopic Bankart failure. However, the size of Hill-Sachs lesion is not a risk factor for failure, in a specific group of on-track Hill-Sachs lesions. Level of evidenceRetrospective Study, Level IV.

Role of MRI at 1- and 3-Month Follow-up in Predicting the Likelihood of Tumor Recurrence Following Percutaneous Cryoablation of Renal Tumors.

To evaluate whether ablation volume difference relatively to tumoral volume, minimal distance between ablation area and necrotic tumor, or apparent diffusion coefficient (ADC) within the ablation area, measured on 1- and 3-month follow-up MRI following cryoablation of renal tumors, are associated with tumor recurrence. 136 renal tumors were retrospectively identified. Patients, tumor characteristics and follow-up MRI (1-, 3-, 6-month, and thereafter annually) were collected. Uni- and multivariate analyses were performed to assess the association between the investigated parameters and tumor recurrence. Over the follow-up period (27.7 ± 21.9months), 13 recurrences were identified at 20.5 ± 19.4months. At 1- and 3-month, the mean volume difference between the ablation zone and the tumor volume were + 577.5 ± 511.3% vs + 251.4 ± 209.8% (p = 0.003), and + 268.8 ± 291.1% vs + 103.8 ± 94.6% (p = 0.023) in patients without and with tumorrecurrence, respectively. At 1- and 3-month, the minimum distance between the necrotic tumor and the edge of the ablation area was 3.4 ± 2.5 vs 1.8 ± 1.9mm (p = 0.019), and 2.4 ± 2.3 vs 1.4 ± 1.8mm (p = 0.13) in patients without and with tumorrecurrence, respectively. Analysis of ADC values was not associated with tumor recurrence. After performing the multivariate analysis, only volume difference of the ablation area compared to tumor volume was associated with absence of tumor recurrence at 1- (OR = 14.1; p = 0.001) and 3-month (OR = 8.2; p = 0.01). Evaluation of volume difference between the ablation area and tumor volume on early (≤ 3months) MRI follow-up identifies patients at risk of tumor recurrence.

FINITE ELEMENT BIOMECHANICAL MODELING OF PAROTID GLAND MORPHING IN PATIENTS UNDERGOING RADIOTHERAPY FOR HEAD AND NECK TUMORS

Patients treated with radiation therapy (RT) for head and neck cancer are exposed during the course of several weeks of treatment (6–7 weeks) to several physiological processes that can induce inter-fraction deformation of the parotid salivary glands (PGs). Gland morphing tends to make them move towards the high dose region of the dose distribution. As a consequence, parotids may be irradiated more than initially planned, leading to increased toxicity. We implemented a biomechanical model of the parotid morphing process that can serve as the basis to optimize adaptive RT protocols, leading to further reductions of dose to these structures. Raystation[Formula: see text] hybrid deformation algorithms and 3DSlicer[Formula: see text] tools were employed to obtain a mesh representation of PG anatomy and deformation from CT-series of eight patients treated with highly modulated radiotherapy (Tomotherapy[Formula: see text]). The biomechanical model was computationally implemented with the finite element software COMSOL[Formula: see text] multiphysics. Gland tissue was modeled as a linear elastic material with a Poisson ratio of 0.49 and a density value of 1 g/cm3. A radial force field was introduced to mimic parotid shrinkage due to radiation exposure. Fixed constraints were placed taking into account the anatomical barrier effect of parotid-surrounding structures (mandible) during the shrinkage process. The implemented biomechanical model was able to predict PG morphing with a mean volume difference of 1.36% [0.9–2.0] % between real and modeled deformed anatomy for the first half of treatment and 1.5% [0.8–2.1]% for the second half of treatment. Prediction of geometric overlap of observed versus simulated geometry as quantified using DICE was acceptable for the first half of the treatment but still unsatisfactory for the second half. Adding model components taking into account other elements that define PG morphing (facial geometry changes due to general weight loss and — in patients with significant macroscopic tumor load - local tumor volume loss) may accurately predict parotid morphing and thus permit further optimization of frequency and timing of off-line ART protocols in patients undergoing radiotherapy for head and neck cancer. This may result in a further reduction of treatment toxicity and these approaches are becoming even more important as the use of particle therapy with its increased dosimetric sensitivity towards geometric changes of the patient is slowly increasing.