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Aim: To assess the feasibility of immediate (IIP), early (EIP) and delayed implant placement (DIP) for single tooth replacement in the premaxilla on the basis of the complete indication area of each approach in routine practice. Materials and Methods: Data from 100 patients (59 women, 41 men, all Caucasians) aged between 19 and 81 years old (mean age 51.71) who had been consecutively treated with a single implant in the premaxilla (13–23) in one private periodontal practice were retrospectively collected. Demographic data, diagnostic information and linear measurements were extracted from patient files and CBCTs. The feasibility of IIP, EIP and DIP was assessed for all cases by both authors, based on the following criteria: availability of apical bone, position of the tooth in relation to the morphology of the alveolar process, buccal bone morphology and presence of midfacial recession. The reasons for not being able to perform an approach, and the viable alternatives for each approach were secondary outcomes. DIP was considered to have been preceded by alveolar ridge preservation (ARP). Results: Ninety‐two patients could be treated by means of IIP, EIP or DIP. In eight patients none of these approaches were possible as they required bone augmentation prior to implant placement. Fifty‐two patients (95% CI: 42%–62%) could by treated with IIP, 58 (95% CI: 48%–67%) with EIP and 88 (95% CI: 80%–93%) with DIP. The feasibility proportions of IIP and EIP were significantly lower than the one of DIP (p < 0.001). All patients who could be treated with IIP could also be treated with EIP or DIP. Lack of apical bone for implant anchorage was the main reason for not being able to perform IIP and EIP. Complete loss of the buccal bone wall and the need for bone augmentation prior to implant placement were the reasons for not being able to perform DIP. Conclusion: From the results of this retrospective CBCT analysis, DIP is nearly always possible in contrast to IIP and EIP. Therefore, and since it is much easier than IIP and EIP, inexperienced clinicians should mainly focus on ARP and DIP in clinical practice deferring IIP and EIP until more surgical skills have been acquired. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to train a 3D U-Net convolutional neural network (CNN) for mandible and lower dentition segmentation from cone-beam computed tomography (CBCT) scans. Methods: In an ambispective cross-sectional design, CBCT scans from two hospitals (2009–2019 and 2021–2022) constituted an internal dataset and external validation set, respectively. Manual segmentation informed CNN training, and evaluations employed Dice similarity coefficient (DSC) for volumetric accuracy. A blinded oral maxillofacial surgeon performed qualitative grading of CBCT scans and object meshes. Statistical analyses included independent t-tests and ANOVA tests to compare DSC across patient subgroups of gender, race, body mass index (BMI), test dataset used, age, and degree of metal artifact. Tests were powered for a minimum detectable difference in DSC of 0.025, with alpha of 0.05 and power level of 0.8. Results: 648 CBCT scans from 490 patients were included in the study. The CNN achieved high accuracy (average DSC: 0.945 internal, 0.940 external). No DSC differences were observed between test set used, gender, BMI, and race. Significant differences in DSC were identified based on age group and the degree of metal artifact. The majority (80%) of object meshes produced by both manual and automatic segmentation were rated as acceptable or higher quality. Conclusion: We developed a model for automatic mandible and lower dentition segmentation from CBCT scans in a demographically diverse cohort including a high degree of metal artifacts. The model demonstrated good accuracy on internal and external test sets, with majority acceptable quality from a clinical grader. [ABSTRACT FROM AUTHOR]

Background Purpose Methods Results Conclusion STereotactic Arrhythmia Radioablation (STAR) is a novel noninvasive method for treating arrythmias in which external beam radiation is directed towards subregions of the heart. Challenges for accurate STAR targeting include small target volumes and relatively large patient motion, which can lead to radiation related patient toxicities. 4D Cone‐beam CT (CBCT) images are used for stereotactic lung treatments to account for respiration‐related patient motion. 4D‐CBCT imaging could similarly be used to account for respiration‐related patient motion in STAR; however, the poor contrast of heart tissue in CBCT makes identifying cardiac substructures in 4D‐CBCT images challenging. If cardiac structures can be identified in pre‐treatment 4D‐CBCT images, then the location of the target volume can be more accurately identified for different phases of the respiration cycle, leading to more accurate targeting and a reduction in patient toxicities.The aim of this simulation study is to investigate the accuracy of different cardiac substructure segmentation methods for 4D‐CBCT images.Repeat 4D‐CT scans from 13 lung cancer patients were obtained from The Cancer Imaging Archive. Synthetic 4D‐CBCT images for each patient were simulated by forward projecting and reconstructing each respiration phase of a chosen “testing” 4D‐CT scan. Eighteen cardiac structures were segmented from each respiration phase image in the testing 4D‐CT using the previously validated platipy toolkit. The platipy segmentations from the testing 4D‐CT were defined as the ground truth segmentations for the synthetic 4D‐CBCT images. Five different 4D‐CBCT cardiac segmentation methods were investigated: 3D Rigid Alignment, 4D Rigid Alignment, Direct CBCT Segmentation, Contour Transformation, and Synthetic CT Segmentation methods. For all methods except the Direct CBCT segmentation method, a separate 4D‐CT (Planning CT) was used to assist in generating 4D‐CBCT segmentations. Segmentation performance was measured using the Dice similarity coefficient (DSC), Hausdorff distance (HD), mean surface distance (MSD), and volume ratio (VR) metrics.The mean ± standard deviation DSC for all cardiac substructures for the 3D Rigid Alignment, 4D Rigid Alignment, Direct CBCT Segmentation, Contour Transformation, and Synthetic CT Segmentation methods were 0.48 ± 0.29, 0.52 ± 0.29, 0.37 ± 0.32, 0.53 ± 0.29, 0.57 ± 0.28, respectively. Similarly, the HD values were 10.9 ± 3.6 , 9.9 ± 2.6 , 17.3 ± 5.3 , 9.9 ± 2.8 , 9.3 ± 3.0 mm, the MSD values were 2.9 ± 0.6 , 2.9 ± 0.6 , 6.3 ± 2.5 , 2.5 ± 0.6 , 2.4 ± 0.8 mm, and the VR Values were 0.81 ± 0.12, 0.78 ± 0.14, 1.10 ± 0.47, 0.72 ± 0.15, 0.98 ± 0.44, respectively. Of the five methods investigated the Synthetic CT segmentation method generated the most accurate segmentations for all calculated segmentation metrics.This simulation study investigates the accuracy of different cardiac substructure segmentation methods for 4D‐CBCT images. Accurate 4D‐CBCT cardiac segmentation will provide more accurate information on the location of cardiac anatomy during STAR treatments which can lead to safer and more effective STAR. As the data and segmentation methods used in this study are all open source, this study provides a useful benchmarking tool to evaluate other CBCT cardiac segmentation methods. [ABSTRACT FROM AUTHOR]

Our purpose was to synthesize evidence in the literature to determine the diagnostic accuracy of cone-beam CT (CBCT) for the detection of intracranial hemorrhage (ICH) and hemorrhage types, including intraparenchymal hemorrhage (IPH), subarachnoid hemorrhage (SAH), and intraventricular hemorrhage (IVH). We performed a meta-analysis following the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. Our protocol was registered with International Prospective Register of Systematic Reviews (PROSPERO-CRD42021261915). Systematic searches were last performed on April 30, 2024, in EMBASE, PubMed, Web-of-Science, Scopus, and Cumulative Index to Nursing and Allied Health Literature databases. Inclusion criteria were (1) studies reporting diagnostic metrics of CBCT for ICH and (2) studies using a reference standard to determine ICH. Exclusion criteria were (1) case reports, abstracts, reviews and (2) studies without patient-level data. Pooled estimates and 95% confidence intervals (CIs) were calculated for diagnostic odds ratios (DORs), sensitivity, and specificity using random-effects and common-effects models. Mixed methods appraisal tool was used to evaluate risk of bias. Seven studies were included in the meta-analysis yielding 466 patients. Mean or median age ranged from 54 to 75 years. Female patients represented 51.4% (222 of 432) in reported studies. Multidetector CT was the reference standard in all studies. DOR, pooled sensitivity, and pooled specificity for ICH were 5.28 (95% CI: 4.11-6.46), 0.88 (95% CI: 0.79-0.97), and 0.99 (95% CI: 0.98-1.0). Pooled sensitivity for IPH, SAH, and IVH was 0.98 (95% CI: 0.95-1.0), 0.82 (95% CI: 0.57-1.0), and 0.78 (95% CI: 0.55-1.0). Pooled specificity for IPH, SAH, and IVH was 0.99 (95% CI: 0.98-1.0), 0.99 (95% CI: 0.97-1.0), and 1.0 (95% CI: 0.98-1.0). CBCT had moderate DOR and high pooled specificity for ICH and hemorrhage types. However, pooled sensitivity varied by hemorrhage type, with the highest sensitivity for IPH, followed by SAH and IVH. [Display omitted] [ABSTRACT FROM AUTHOR]

Increasingly, interventional thoracic workflows utilize cone-beam CT (CBCT) to improve navigational and diagnostic yield. Here, we investigate the feasibility of implementing free-breathing 4D respiratory CBCT for motion mitigated imaging in patients unable to perform a breath-hold or without suspending mechanical ventilation during thoracic interventions. Circular 4D respiratory CBCT imaging trajectories were implemented on a clinical robotic CBCT system using additional real-time control hardware. The circular trajectories consisted of 1 × 360° circle at 0° tilt with fixed gantry velocities of 2°/s, 10°/s, and 20°/s. The imaging target was an in-house developed anthropomorphic breathing thorax phantom with deformable lungs and 3D-printed imaging targets. The phantom was programmed to reproduce 3 patient-measured breathing traces. Following image acquisition, projections were retrospectively binned into ten respiratory phases and reconstructed using filtered back projection, model-based, and iterative motion compensated algorithms. A conventional circular acquisition on the system of the free-breathing phantom was used as comparator. Edge Response Width (ERW) of the imaging target boundaries and Contrast-to-Noise Ratio (CNR) were used for image quality quantification. All acquisitions across all traces considered displayed visual evidence of motion blurring, and this was reflected in the quantitative measurements. Additionally, all the 4D respiratory acquisitions displayed a lower contrast compared to the conventional acquisitions for all three traces considered. Overall, the current implementation of 4D respiratory CBCT explored in this study with various gantry velocities combined with motion compensated algorithms improved image sharpness for the slower gantry rotations considered (2°/s and 10°/s) compared to conventional acquisitions over a variety of patient traces. [ABSTRACT FROM AUTHOR]

Purpose: Cone-beam CT in the interventional suite could be an alternative to CT to shorten door-to-thrombectomy time. However, image quality in cone-beam CT is limited by artifacts and poor differentiation between gray and white matter. This study compared non-contrast brain dual-layer cone-beam CT in the interventional suite to reference standard CT in stroke patients. Methods: A prospective single-center study enrolled consecutive participants with ischemic or hemorrhagic stroke. The hemorrhage detection accuracy, per-region ASPECTS accuracy and subjective image quality (Likert scales for gray-white matter differentiation, structure perception and artifacts) were assessed by three neuroradiologists blinded to clinical data on dual-layer cone-beam CT 75 keV monoenergetic images compared to CT. Objective image quality was assessed by region-of-interest metrics. Non-inferiority for hemorrhage detection and ASPECTS accuracy was determined by the exact binomial test with a one-sided lower performance boundary prospectively set to 80% (98.75% CI). Results: 27 participants were included (74 years ± 9; 19 female) in the hyperacute or acute stroke phase. One reader missed a small bleeding, but all hemorrhages were detected in the majority analysis (100% accuracy, CI lower boundary 86%, p = 0.002). ASPECTS majority analysis showed 90% accuracy (CI lower boundary 85%, p < 0.001). Sensitivity was 66% (individual readers 67%, 69%, and 76%), specificity was 97% (97%, 96%, 89%). Subjective and objective image quality were inferior to CT. Conclusion: In a small single-center cohort, dual-layer cone-beam CT showed non-inferior hemorrhage detection and ASPECTS accuracy to CT. Despite inferior image quality, the technique may be useful for stroke evaluation in the interventional suite. Trial Registration Number: NCT04571099 (clinicaltrials.gov). Prospectively registered 2020-09-04. [ABSTRACT FROM AUTHOR]

BACKGROUND: With the development and progress in the field of stomatology, oral implant technology has gradually become the mainstream alternative to traditional dentures. In recent years, the maturity of various bone increment techniques and the continuous development of the oral digital field have expanded the indications of dental implantation, and the success rate of implantation surgery is also increasing. However, it has become a difficult problem for some clinicians to use cone-beam computed tomography (CBCT) to accurately measure the residual alveolar ridge bone mass before implantation and to make a suitable implantation plan. OBJECTIVE: To measure the residual alveolar ridge bone mass in the proposed implant area of the mandibular first molar using the CBCT. METHODS: In a retrospective study design, the CBCT images of 205 patients with mandibular first molar loss were included to measure the height and width of the residual alveolar ridge in the proposed implant area of the mandibular first molar. The residual alveolar ridges were divided into four categories: I, II, III and IV (Class II, III, and IV residual alveolar ridge defined as insufficient bone). Statistical analyses were conducted in terms of frequency distribution of residual alveolar ridge height, width, and morphology of the mandibular first molar, differences in residual alveolar ridge height and alveolar ridge crest width of the mandibular first molar in patients of different sexes, correlation of the residual alveolar ridge height with the crest width and bottom width of the residual alveolar ridge, as well as correlation of age with the width and height of the residual alveolar ridge crest. RESULTS AND CONCLUSION: (1) The average height of the residual alveolar ridge in the proposed implant area of the mandibular first molar was (12.14±2.96) mm, of which 43.41% (89/205) were less than 12 mm. The average width of the residual alveolar ridge in the proposed implant area of the mandibular first molar was (6.80±1.65) mm, of which 26.34% (54/205) were less than 6 mm. (2) The height of the residual alveolar ridge of the mandibular first molar was higher in males than in females, with no significant difference (P > 0.05), and the width of the residual alveolar ridge of the mandibular first molar was significantly wider in males than in females (P < 0.01). (3) The height of the residual alveolar ridge was negatively correlated with the top and bottom width of the residual alveolar ridge (P < 0.01). Age showed a positive correlation with the residual alveolar ridge width (P < 0.05) and no significant correlation with the residual alveolar ridge height (P > 0.05). (4) The residual alveolar ridge of class I accounted for 58.05% (119/205), class II accounted for 9.27% (19/205), class III accounted for 20.49% (42/205), and class IV accounted for 12.19% (25/205), most of which were class III with insufficient remaining alveolar ridge bone mass. Clinicians need to individualize and design the optimal implantation plan based on the type of residual alveolar ridge. [ABSTRACT FROM AUTHOR]

Objective To explore the influence of apical dense bone islands on tooth movement during orthodontic treatment and its complications, and to provide a reference for orthodontic clinical treatment. Methods This study obtained approval from the hospital ethics committee. A retrospective analysis was conducted on 33 patients with apical dense bone islands who received full-mouth fixed orthodontic treatment in the Orthodontics Department of Huizhou Stomatological Hospital from 2018 to 2022. Cone-beam CT (CBCT) was used to determine the location, distribution, and wrapping severity of the apical dense bone islands before treatment. The number of loose teeth located in the apical dense bone islands and the degree of external apical root resorption in the apical area of teeth were analyzed before treatment, immediately after treatment, and 12 months after treatment. Results There were 33 orthodontic patients (aged 11 to 42 years, with an average age of 16.7 years and a median age of 15 years) included in this study, including 12 males (36.4%) and 21 females (63.6%). All apical dense bone islands involved a single tooth located in the mandible, mainly in the premolar-molar area. No gender differences were present in the location of the dense bone islands (P>0.05). The apical dense bone islands were mildly wrapped in 23 cases (69.7%), moderately wrapped in 10 cases (30.3%), and severely wrapped in no cases. No difficulty in tooth movement or incomplete closure of extraction space was found in the apical dense bone islands with different degrees of wrapping during orthodontic treatment. For teeth located in apical dense bone islands, 1 patient (3.0%) had loose teeth before treatment, 6 patients (18.2%) had loose teeth after treatment, and 2 patients (6.1%) had loose teeth 12 months after treatment. The number of patients with grade I loose teeth increased after treatment and 12 months after treatment. There was a statistically significant difference in the number of loose teeth before and after treatment (PP>0.05), and no statistically significant difference in the number of loose teeth after treatment and 12 months after treatment (P>0.05). After treatment, apical dense bone islands showed mild resorption in 26 cases (78.8%), moderate resorption in 7 cases (21.2%), and severe resorption in no cases. The apical dense bone islands showed mild resorption in 25 cases (75.8%), moderate resorption in 8 cases (24.2%), and severe resorption in no cases 12 months after treatment. For the severity of root resorption, there was a statistically significant difference between before and after treatment (PPP>0.05). Conclusion Apical dense bone islands were not found to affect tooth movement during orthodontic treatment. After orthodontic treatment, the number of loose teeth increased and mild-to-moderate tooth external apical root resorption occurred, which may be a potential risk of external apical root resorption. Thus, it is recommended to pay close attention during the orthodontic process.

Objective To investigate the differences in the morphological structure and spatial position of the temporomandibular joint among patients with different sagittal skeletal patterns. Methods A total of 68 young adults with malocclusion were enrolled and allocated into skeletal Class Ⅰ group, skeletal Class Ⅱ group and skeletal Class Ⅲ group according to sagittal skeletal patterns. InVivo 5 software was used to reconstruct the cone-beam CT images of all patients, and 17 research items related to condyle, glenoid fossa and articular eminence were measured and analyzed. Results There was no significant difference in the morphological structure and spatial position of bilateral temporomandibular joints in patients regardless of sagittal skeletal patterns(P

Purpose: To provide detailed reports on radiation doses during transarterial chemoembolization (TACE) in the cone-beam computed tomography (CBCT) era and to identify the associated factors. Methods: This retrospective study included 385 consecutive patients who underwent initial conventional TACE for hepatocellular carcinoma (HCC) between January 2016 and December 2017. In most cases, CBCT was performed at the common hepatic artery or celiac axis to confirm the location of the tumor and the three-dimensional hepatic artery anatomy. Superselective TACE was performed for all technically feasible cases. Information on total dose area product (DAP), total cumulative air kerma (CAK), fluoroscopy time, and DAP and CAK of each digital subtraction angiography (DSA) and CBCT scan was recorded. Multiple linear regression analysis was performed to identify the factors associated with increased DAP during TACE. Results: The mean values of total DAP and CAK were 165.2 ± 81.2 (Gy·cm²) and 837.1 ± 571.0 (mGy), respectively. The mean fluoroscopy time was 19.1 ± 10.3 min. The mean DAP caused by fluoroscopy, DSA, and CBCT was 51.8 ± 43.9, 28.0 ± 24.1, and 83.9 ± 42.1 Gy·cm², respectively. Male sex, a high body mass index, largest tumor size > 3 cm, presence of aberrant right and left hepatic arteries, and superselective TACE were identified as independent predictors of increased total DAP during TACE. Conclusion: We were able to provide detailed reports on radiation doses during TACE and associated factors. [ABSTRACT FROM AUTHOR]

Copyright of China Journal of Oral & Maxillofacial Surgery is the property of Shanghai Jiao Tong University, College of Stomatology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: To create and evaluate prediction models of local tumor recurrence after successful conventional transcatheter arterial chemoembolization (c-TACE) via radiomics analysis of lipiodol deposition using cone-beam computed tomography (CBCT) images obtained at the completion of TACE. Materials and Methods: A total of 103 hepatocellular carcinoma nodules in 71 patients, who achieved a complete response (CR) based on the modified Response Evaluation Criteria in Solid Tumors 1 month after TACE, were categorized into two groups: prolonged CR and recurrence groups. Three types of areas were segmented on CBCT: whole segment (WS), tumor segment (TS), and peritumor segment (PS). From each segment, 105 radiomic features were extracted. The nodules were randomly divided into training and test datasets at a ratio of 7:3. Following feature reduction for each segment, three models (clinical, radiomics, and clinical–radiomics models) were developed to predict recurrence based on logistic regression. Results: The clinical–radiomics model of WS showed the best performance, with the area under the curve values of 0.853 (95% confidence interval: 0.765–0.941) in training and 0.752 (0.580–0.924) in test dataset. In the analysis of radiomic feature importance of all models, among all radiomic features, glcm_MaximumProbability, shape_MeshVolume and shape_MajorAxisLength had negative coefficients. In contrast, shape_SurfaceVolumeRatio, shape_Elongation, glszm_SizeZoneNonUniformityNormalized, and gldm_GrayLevelNonUniformity had positive coefficients. Conclusion: In this study, a machine-learning model based on cone-beam CT images obtained at the completion of c-TACE was able to predict local tumor recurrence after successful c-TACE. Nonuniform lipiodol deposition and irregular shapes may increase the likelihood of recurrence. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the feasibility of an open‐source, semi‐automated, and reproducible vertex placement tool to improve the efficiency of lattice radiotherapy (LRT) planning. We used polymer gel dosimetry with a Cone Beam CT (CBCT) readout to commission this LRT technique. Material and methods: We generated a volumetric modulated arc therapy (VMAT)‐based LRT plan on a 2 L NIPAM polymer gel dosimeter using our Eclipse Acuros version 15.6 AcurosXB beam model, and also recalculated the plan with a pre‐clinical Acuros v18.0 dose calculation algorithm with the enhanced leaf modelling (ELM). With the assistance of the MAAS‐SFRThelper software, a lattice vertex diameter of 1.5 cm and center‐to‐center spacing of 3 cm were used to place the spheres in a hexagonal, closed packed structure. The verification plan included four gantry arcs with 15°, 345°, 75°, 105° collimator angles. The spheres were prescribed 20 Gy to 50% of their combined volume. The 6 MV Flattening Filter Free beam energy was used to deliver the verification plan. The dosimetric accuracy of the LRT delivery was evaluated with 1D dose profiles, 2D isodose maps, and a 3D global gamma analysis. Results: Qualitative comparisons between the 1D dose profiles of the Eclipse plan and measured gel showed good consistency at the prescription dose mark. The average diameter measured 13.3 ± 0.2 mm (gel for v15.6), 12.6 mm (v15.6 plan), 13.1 ± 0.2 mm (gel for v18.0), and 12.3 mm (v18.0 plan). 3D gamma analysis showed that all gamma pass percent were > 95% except at 1% and 2% at the 1 mm distance to agreement criteria. Conclusion: This study presents a novel application of gel dosimetry in verifying the dosimetric accuracy of LRT, achieving excellent 3D gamma results. The treatment planning was facilitated by publicly available software that automatically placed the vertices for consistency and efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Prevention & Treatment For Stomatological Diseases is the property of Journal of Prevention & Treatment For Stomatological Diseases Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: The objective of this study was to enhance the visibility of soft tissues on cone-beam computed tomography (CBCT) using a CycleGAN network trained on CT images. Methods: Training and evaluation of the CycleGAN were conducted using CT and CBCT images collected from Aichi Gakuin University (α facility) and Osaka Dental University (β facility). Synthesized images (sCBCT) output by the CycleGAN network were evaluated by comparing them with the original images (oCBCT) and CT images, and assessments were made using histogram analysis and human scoring of soft-tissue anatomical structures and cystic lesions. Results: The histogram analysis showed that on sCBCT, soft-tissue anatomical structures showed significant shifts in voxel intensity toward values resembling those on CT, with the mean values for all structures approaching those of CT and the specialists' visibility scores being significantly increased. However, improvement in the visibility of cystic lesions was limited. Conclusions: Image synthesis using CycleGAN significantly improved the visibility of soft tissue on CBCT, with this improvement being particularly notable from the submandibular region to the floor of the mouth. Although the effect on the visibility of cystic lesions was limited, there is potential for further improvement through refinement of the training method. [ABSTRACT FROM AUTHOR]

Introduction: Dental implants are the most popular alternative to rehabilitation of missing teeth and oro-facial structures. The outcome of such procedures depends on various factors and most-importantly on the osseo-integation with the surrounding bone. The evaluation needs better visualization and evaluation using CBCT anaylsis and determination of HU, using an appropriate software. Materials and Methods: This prospective cohort study was conducted at a tertiary level teaching hospital. A total of 129 cases were considered for the study after applying the laid down inclusion and exclusion criteria. Implant placement was done by single operator for placement of the endosteal implant (AB implant system Inc). All implants were placed using a minimum insertion torque of 25 Ncm as assessed by the physio-dispenser (NSK). The HU numbers were obtained at specified areas after immediate and 24 weeks post-operative period. The cases were divided into Augmented cases (Group I) and non-augmented cases (Group II). The augmented cases utilised Novabone putty bone graft. Results: The study showed homogenous distribution of skewness and kurtosis in both the groups. The initial increase in augmented cases was due to increased radio-opacity of the graft. The HU values reached to near normal in both groups with no significant difference. The statistical test needed to analyze equality of variances, Levene's test was considered to ascertain the level of significance. Although the variance of subjects in group I is significantly different from that of group II, the test concludes that equal variances are not assumed. This prompts us to reject the null hypothesis at hand. Conclusion: The use of augmentation as in this case with a bone putty show no significant improvement in improved bone quality at accelerated time. The study may need to be further augmented with research. [ABSTRACT FROM AUTHOR]

Dedicated breast CT is an imaging modality that provides true 3D imaging of the breast with many advantages over current conventional breast imaging modalities. The addition of intravascular contrast increases the sensitivity of breast CT substantially. As such, there are immediate potential applications in the clinical workflow. These include using breast CT to replace much of the traditional diagnostic workup when faced with indeterminate breast lesions. Contrast-enhanced breast CT may be appropriate as a supplemental screening tool for women at high risk of breast cancer, similar to breast MRI. In addition, emerging studies are demonstrating the utility of breast CT in neoadjuvant chemotherapy tumor response monitoring as well as planning for surgical treatment options. While short exam times and fully 3D imaging in a noncompressed position are advantages of this modality, limited coverage of chest wall/axilla due to prone positioning and use of ionizing radiation are drawbacks. To date, several studies have reported on the performance characteristics of this promising modality. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to evaluate the anatomy of the pterygomaxillary region and the position of the descending palatine artery using CBCT sections. Methods: In this analytical cross-sectional study, an evaluation of CBCT scans from 280 patients was undertaken. Axial sections of these images were utilized to determine the thickness, width, and location of the descending palatine artery, as well as the length of the pterygoid plates within the pterygomaxillary region. Convenient sampling was employed to gather these CBCT scans. Results: The mean anterior length was higher in men (41.1 ± 5.6 vs.39.8 ± 6.2) (both with P<0.05). The mean length of lateral plate was 12.07 ± 2.2 and 11.1 ± 2.5 mm in men and women, respectively on the right side (P=0.001) and it is significantly higher in men (12.5 ± 4.7 vs. 11.1 ± 2.5) on the left side (P=0.002). The mean length of the medial plate in men and women was nearly similar and significant on the left side (P=0.005). The thickness of the trigomaxillary region and the nerigoid appendage were not significantly different in men and women and both sides. It has been determined that the distance between the descending palatine canal and the priform rim is longer in females on both sides. Conclusion: The intricate morphology of the pterygomaxillary region can harbor anatomical variations that increase the risk of specific complications during Le Fort I osteotomy. To mitigate these potential risks, pre-operative imaging with CBCT is crucial for scrutinizing the pterygomaxillary region. [ABSTRACT FROM AUTHOR]

Objective. The TOol for PArticle Simulation (TOPAS) is a Geant4-based Monte Carlo software application that has been used for both research and clinical studies in medical physics. So far, most users of TOPAS have focused on radiotherapy-related studies, such as modeling radiation therapy delivery systems or patient dose calculation. Here, we present the first set of TOPAS extensions to make it easier for TOPAS users to model medical imaging systems.Approach. We used the extension system of TOPAS to implement pre-built, user-configurable geometry components such as detectors (e.g. flat-panel and multi-planar detectors) for various imaging modalities and pre-built, user-configurable scorers for medical imaging systems (e.g. digitizer chain).Main results. We developed a flexible set of extensions that can be adapted to solve research questions for a variety of imaging modalities. We then utilized these extensions to model specific examples of cone-beam CT (CBCT), positron emission tomography (PET), and prompt gamma (PG) systems. The first of these new geometry components, the FlatImager, was used to model example CBCT and PG systems. Detected signals were accumulated in each detector pixel to obtain the intensity of x-rays penetrating objects or prompt gammas from proton-nuclear interaction. The second of these new geometry components, the RingImager, was used to model an example PET system. Positron-electron annihilation signals were recorded in crystals of the RingImager and coincidences were detected. The simulated data were processed using corresponding post-processing algorithms for each modality and obtained results in good agreement with the expected true signals or experimental measurement.Significance. The newly developed extension is a first step to making it easier for TOPAS users to build and simulate medical imaging systems. Together with existing TOPAS tools, this extension can help integrate medical imaging systems with radiotherapy simulations for image-guided radiotherapy.

Medication-related osteonecrosis of the jaw (MRONJ) is an adverse reaction caused by the use of antiresorptive antiangiogenic medication. The most commonly affected areas are posterior regions of mandible and maxilla. However, a simultaneous occurrence in both jaws is rarely observed. We present an interesting case of MRONJ affecting both jaws. A 47-year-old female presented with pain and swelling in the left posterior region of the mandible. The patient’s medical history was significant for breast cancer with ongoing bisphosphonate therapy. Cone-beam computerized tomography (CBCT) confirmed the presence of an extraction socket at the site of complaint. There was evidence of a diffuse sclerotic bone reaction in the maxillary posterior region bilaterally. The mandible showed presence of diffuse sclerotic bone only in the left para-symphysis and posterior region in addition to association with a periosteal bone reaction in the left para-symphysis region. Considering these findings and a history of exposure to bisphosphonate medication, the final diagnosis was conclusive of MRONJ. Management was aimed at suppressing the symptoms of pain and infection. The present case study reinforces the importance of correlating clinical and radiographic findings. Early diagnosis of MRONJ may lead to a more conservative treatment approach, greatly improving the patient’s prognosis. [ABSTRACT FROM AUTHOR]

Many scenarios in dental clinical diagnosis and treatment require the segmentation and identification of a specific tooth or the entire dentition in cone‐beam computed tomography (CBCT) images. However, traditional segmentation methods struggle to ensure accuracy. In recent years, there has been significant progress in segmentation algorithms based on deep learning, garnering considerable attention. Inspired by models from present neuro networks such as UCTransNet and DC‐Unet, this study proposes an MRCM‐UCTransNet for accurate three‐dimensional tooth segmentation from cone‐beam CT images. To enhance feature extraction while preserving the multi‐head attention mechanism, a multi‐scale residual convolution module (MRCM) is integrated into the UCTransNet architecture. This modification addresses the limitations of traditional segmentation methods and aims to improve accuracy in tooth segmentation from CBCT images. Comparative experiments indicate that, in the situation with a specific image size and small data volume, the proposed method exhibits certain advantages in segmentation accuracy and precision. Compared to traditional Unet approaches, MRCM‐UCTransNet's dice accuracy is improved by 7%, while its sensitivity is improved by about 10%. These findings highlight the efficacy of the proposed approach, particularly in scenarios with specific image size constraints and limited data availability. The proposed MRCM‐UCTransNet algorithm integrates the latest architectural advancements in the Unet model which achieves effective segmentation of six types of teeth within the tooth. It was proved to be efficient for image segmentation on small datasets, requiring less training time and fewer parameters. [ABSTRACT FROM AUTHOR]

Purpose: Intraoperative cone-beam CT imaging enables 3D validation of implant positioning and fracture reduction for orthopedic and trauma surgeries. However, the emergence of metal artifacts, especially in the vicinity of metallic objects, severely degrades the clinical value of the imaging modality. In previous works, metal artifact avoidance (MAA) methods have been shown to reduce metal artifacts by adapting the scanning trajectory. Yet, these methods fail to translate to clinical practice due to remaining methodological constraints and missing workflow integration. Methods: In this work, we propose a method to compute the spatial distribution and calibrated strengths of expected artifacts for a given tilted circular trajectory. By visualizing this as an overlay changing with the C-Arm's tilt, we enable the clinician to interactively choose an optimal trajectory while factoring in the procedural context and clinical task. We then evaluate this method in a realistic human cadaver study and compare the achieved image quality to acquisitions optimized using global metrics. Results: We assess the effectiveness of the compared methods by evaluation of image quality gradings of depicted pedicle screws. We find that both global metrics as well as the proposed visualization of artifact distribution enable a drastic improvement compared to standard non-tilted scans. Furthermore, the novel interactive visualization yields a significant improvement in subjective image quality compared to the state-of-the-art global metrics. Additionally we show that by formulating an imaging task, the proposed method allows to selectively optimize image quality and avoid artifacts in the region of interest. Conclusion: We propose a method to spatially resolve predicted artifacts and provide a calibrated measure for artifact strength grading. This interactive MAA method proved practical and effective in reducing metal artifacts in the conducted cadaver study. We believe this study serves as a crucial step toward clinical application of an MAA system to improve image quality and enhance the clinical validation of implant placement. [ABSTRACT FROM AUTHOR]

BACKGROUND: Traditional lateral cephalometric radiographs always suffer from some problems, such as magnification distortion, left and right overlap inconsistency and so on, while the cone-beam CT can truly display the three-dimensional structure of the craniofacial region. Performing three-dimensional reconstruction of cone-beam CT and then transforming the cone-beam CT in the selected area into the two-dimensional image can make the overlap between the left and right sides consistent and reduce the influence of surrounding tissue structures. OBJECTIVE: To explore the consistency of quantitative analysis of cervical vertebral bone age between two kinds of cone-beam CT transformed twodimensional images with different integrated thicknesses and traditional lateral cephalometric radiographs. METHODS: The cone-beam CT and lateral cephalometric radiograph data of 118 adolescent orthodontic patients were collected. Firstly, the cone-beam CT image was reconstructed in 3D imaging software. After reconstruction, two types of cone-beam CT images with different integrated thicknesses were selected in the sagittal interface and transformed into two-dimensional images, which were named ICB-1 and ICB-2, respectively. The Zhibeiyun system was used to measure and calculate the angle between the concave base of the second cervical vertebra and the lower edge of the vertebral body (@2), the ratio of the third cervical spine to the posterior height (AH3/PH3), the ratio of height to width of the fourth cervical spine (H4/W4) in lateral cephalometric radiograph, ICB-1, ICB-2 and the cervical vertebral bone age. After an interval of two weeks, 20 adolescents were randomly selected to repeat the above measurements. The intraclass correlation coefficient (ICC) method was used to evaluate the repeatability of the three images in measuring cervical bone age. Paired t-test was used to analyze the consistency of cervical bone age measurements between the three images. The Kappa test was used to analyze the consistency of cervical vertebral bone age staging assessment between the three images. RESULTS AND CONCLUSION: (1) ICC of AH3/PH3 in the lateral cephalometric radiograph group was < 0.9, and the ICC of other measurement items in each group was > 0.9. (2) Paired t-test results showed that there were statistical differences in AH3/PH3 and H4/W4 between the ICB-1 group and lateral cephalometric radiograph group and between the ICB-1 group and ICB-2 group (P < 0.05), and there were no statistically significant differences in the other items between the three groups (P > 0.05). (3) The Kappa test results showed that the Kappa coefficients of the two groups were all more than 0.8 according to the staging of cervical vertebral bone age in three groups (P < 0.001). (4) It is indicated that the repeatability of ICB-1 and ICB-2 in the measurement of cervical vertebral bone age is better than that of lateral cephalometric radiographs. Lateral cephalometric radiographs, ICB-1 and ICB-2 have good consistency in the measurement of cervical vertebral bone age, but considering the integrity of cervical vertebra structure, ICB-2 is more suitable for quantitative analysis of cervical vertebral bone age than ICB-1. [ABSTRACT FROM AUTHOR]

Cerebral blood volume mapping can characterize hemodynamic changes within brain tissue, particularly after stroke. This study aims to quantify blood volume changes in the perihematomal parenchyma and pericavity parenchyma after minimally invasive intracerebral hemorrhage evacuation (MIS for ICH). Thirty-two patients underwent MIS for ICH with pre- and post-operative CT imaging and intraoperative perfusion imaging (DynaCT PBV Neuro, Artis Q, Siemens). The pre-operative and post-operative CT scans were segmented using ITK-SNAP software to calculate hematoma volumes and to delineate the pericavity tissue. Helical CT segmentations were registered to cone beam CT data using elastix software. Mean blood volumes were computed inside subvolumes by dilating the segmentations at increasing distances from the lesion. Pre-operative perihematomal blood volumes and post-operative pericavity blood volumes (PBV) were compared. In 27 patients with complete imaging, post-operative PBV significantly increased within the 6-mm pericavity region after MIS for ICH. The mean relative PBV increased by 21.6 and 9.1% at 3 mm and 6 mm, respectively (P = 0.001 and 0.016, respectively). At the 9-mm pericavity region, there was a 2.83% increase in mean relative PBV, though no longer statistically significant. PBV analysis demonstrated a significant increase in pericavity cerebral blood volume after minimally invasive ICH evacuation to a distance of 6 mm from the border of the lesion. [ABSTRACT FROM AUTHOR]

ObjectiveTo measure the palatal soft tissue thickness and cortical bone density to determine safe regions for the placement of orthodontic mini-implants and to examine the influence of sex and age on soft tissue thickness and cortical bone density.Materials and methodsCone-beam computed tomography images of 42 patients (22 males and 20 females), including 21 adults and 21 adolescents, were examined in this study. The palatal soft tissue thickness and cortical bone density were measured at the coronal planes between the premolars (P4–5), between the second premolars and first molars (P5–6), and between the first molars and second molars (P6–7).ResultsThe thickness of the soft tissue revealed similar coronal planes, but the bone density varied. The mean thickness was 3.8 mm at 0°–60° and 1.5 mm at 60°–90°. P4–5 had the highest bone density (>600 HU), decreasing toward P6–7 (

Background and Purpose: Poor image quality of cone-beam computed tomography (CBCT) images can hinder proton dose calculation to assess the influence of anatomy changes. The aim of this study was to evaluate image quality and proton dose calculation accuracy of synthetic CTs generated from CBCT using unsupervised 3D deep-learning networks. Materials and methods: A total of 102 head-and-neck cancer patients were used to train (N=82) and test (N=20) i) a cycle-consistent generative adversarial network, ii) a contrastive unpaired translation, and iii) a fusion of the two (CycleCUT). For patients in the test set, a repeat CT was deformably registered to a same-day CBCT to create a ground-truth CT for comparison. The proton plan was re-calculated on the ground-truth CT and synthetic CTs. The image quality of the synthetic CTs was evaluated using peak signal-to-noise ratio, structural similarity index measure, mean error, and mean absolute error (MAE). Proton dose calculation accuracy was assessed through 3D gamma analysis and dose-volume-histogram parameters. Results: All synthetic CTs accurately preserved the CBCT anatomy (verified by visual inspection) while improving the image quality. The CycleCUT network had slightly improved image quality compared to the other networks (MAE in body: 53 Hounsfield units (HU) vs. 54/55 HU). All networks had similar proton dose calculation accuracy with gamma passing rate above 97%. Conclusions: All three evaluated networks generated synthetic CT images with dose distributions comparable to those of conventional fan-beam CT. The synthetic CT generation was fast, making all networks feasible for adaptive proton therapy.

Abstract Cone‐beam computed tomography (CBCT) system can provide real‐time 3D images and fluoroscopy images of the region of interest during the operation. Some systems can even offer augmented fluoroscopy and puncture guidance. The use of CBCT for interventional pulmonary procedures has grown significantly in recent years, and numerous clinical studies have confirmed the technology's efficacy and safety in the diagnosis, localization, and treatment of pulmonary nodules. In order to optimize and standardize the technical specifications of CBCT and guide its application in clinical practice, the consensus statement has been organized and written in a collaborative effort by the Professional Committee on Interventional Pulmonology of China Association for Promotion of Health Science and Technology.

Purpose: This study aimed to assess the margin for the planning target volume (PTV) using the Van Herk formula. We then validated the proposed margin by real-time magnetic resonance imaging (MRI). Methods: An analysis of cone-beam computed tomography (CBCT) data from early glottic cancer patients was performed to evaluate organ motion. Deformed clinical target volumes (CTV) after rigid registration were acquired using the Velocity program (Varian Medical Systems, Palo Alto, CA, USA). Systematic (Σ) and random errors (σ) were evaluated. The margin for the PTV was defined as 2.5 Σ + 0.7 σ according to the Van Herk formula. To validate this margin, we accrued healthy volunteers. Sagittal real-time cine MRI was conducted using the ViewRay system (ViewRay Inc., Oakwood Village, OH, USA). Within the obtained sagittal images, the vocal cord was delineated. The movement of the vocal cord was summed up and considered as the internal target volume (ITV). We then assessed the degree of overlap between the ITV and the PTV (vocal cord plus margins) by calculating the volume overlap ratio, represented as (ITV∩PTV)/ITV. Results: CBCTs of 17 early glottic patients were analyzed. Σ and σ were 0.55 and 0.57 for left–right (LR), 0.70 and 0.60 for anterior–posterior (AP), and 1.84 and 1.04 for superior–inferior (SI), respectively. The calculated margin was 1.8 mm (LR), 2.2 mm (AP), and 5.3 mm (SI). Four healthy volunteers participated for validation. A margin of 3 mm (AP) and 5 mm (SI) was applied to the vocal cord as the PTV. The average volume overlap ratio between ITV and PTV was 0.92 (range 0.85–0.99) without swallowing and 0.77 (range 0.70–0.88) with swallowing. Conclusion: By evaluating organ motion by using CBCT, the margin was 1.8 (LR), 2.2 (AP), and 5.3 mm (SI). The margin acquired using CBCT fitted well in real-time cine MRI. Given that swallowing during radiotherapy can result in a substantial displacement, it is crucial to consider strategies aimed at minimizing swallowing and related motion. [ABSTRACT FROM AUTHOR]

Objective. The aim of this study was to reconstruct volumetric computed tomography (CT) images in real-time from ultra-sparse two-dimensional x-ray projections, facilitating easier navigation and positioning during image-guided radiation therapy. Approach. Our approach leverages a voxel-sapce-searching Transformer model to overcome the limitations of conventional CT reconstruction techniques, which require extensive x-ray projections and lead to high radiation doses and equipment constraints. Main results. The proposed XTransCT algorithm demonstrated superior performance in terms of image quality, structural accuracy, and generalizability across different datasets, including a hospital set of 50 patients, the large-scale public LIDC-IDRI dataset, and the LNDb dataset for cross-validation. Notably, the algorithm achieved an approximately 300% improvement in reconstruction speed, with a rate of 44 ms per 3D image reconstruction compared to former 3D convolution-based methods. Significance. The XTransCT architecture has the potential to impact clinical practice by providing high-quality CT images faster and with substantially reduced radiation exposure for patients. The model's generalizability suggests it has the potential applicable in various healthcare settings. [ABSTRACT FROM AUTHOR]

The Feldkamp, Davis and Kress algorithm is a computationally efficient reconstruction method for three-dimensional cone-beam computed tomography. However, it suffers from severe artefacts when the number of projections is insufficient. Although recent deep learning–based methods have succeeded in reconstructing such sparse-view projections, it is still challenging to reconstruct a large 3D volume efficiently because of heavy memory consumption and difficulty in obtaining sufficient training data. Therefore, we propose a deep learning method to overcome these drawbacks. Our method consecutively reconstructs short bars in 3D CT volume using the intensities of pixels on the moving trajectory projected on the detector of these bars. Then, we feed such pixel intensities into a neural network and train it to simulate the filtering and back-projection processes of the FDK algorithm. Since the reconstruction volume is separated into bars, the neural network can be used with only a small amount of memory. Furthermore, the network can be trained sufficiently with only a few training samples because plenty of bar data can be extracted even from a single CT image. We experimentally demonstrate that our approach works efficiently for both simulated and actual sparse-view CBCT data using training data extracted from only a single CT image. [ABSTRACT FROM AUTHOR]

Background: Cone‐beam CT (CBCT) has been extensively employed in industrial and medical applications, such as image‐guided radiotherapy and diagnostic imaging, with a growing demand for quantitative imaging using CBCT. However, conventional CBCT can be easily compromised by scatter and beam hardening artifacts, and the entanglement of scatter and spectral effects introduces additional complexity. Purpose: The intertwined scatter and spectral effects within CBCT pose significant challenges to the quantitative performance of spectral imaging. In this work, we present the first attempt to develop a stationary spectral modulator with flying focal spot (SMFFS) technology as a promising, low‐cost approach to accurately solving the x‐ray scattering problem and physically enabling spectral imaging in a unified framework, and with no significant misalignment in data sampling of spectral projections. Methods: To deal with the intertwined scatter‐spectral challenge, we propose a novel scatter‐decoupled material decomposition (SDMD) method for SMFFS, which consists of four steps in total, including (1) spatial resolution‐preserved and noise‐suppressed multi‐energy "residual" projection generation free from scatter, based on a hypothesis of scatter similarity; (2) first‐pass material decomposition from the generated multi‐energy residual projections in non‐penumbra regions, with a structure similarity constraint to overcome the increased noise and penumbra effect; (3) scatter estimation for complete data; and (4) second‐pass material decomposition for complete data by using a multi‐material spectral correction method. Monte Carlo simulations of a pure‐water cylinder phantom with different focal spot deflections are conducted to validate the scatter similarity hypothesis. Both numerical simulations using a clinical abdominal CT dataset, and physics experiments on a tabletop CBCT system using a Gammex multi‐energy CT phantom and an anthropomorphic chest phantom, are carried out to demonstrate the feasibility of CBCT spectral imaging with SMFFS and our proposed SDMD method. Results: Monte Carlo simulations show that focal spot deflections within a range of 2 mm share quite similar scatter distributions overall. Numerical simulations demonstrate that SMFFS with SDMD method can achieve better material decomposition and CT number accuracy with fewer artifacts. In physics experiments, for the Gammex phantom, the average error of the mean values (ERMSEROI$E^{\text{ROI}}_{\text{RMSE}}$) in selected regions of interest (ROIs) of virtual monochromatic image (VMI) at 70 keV is 8 HU in SMFFS cone‐beam (CB) scan, and 19 and 210 HU in sequential 80/120 kVp (dual kVp, DKV) CB scan with and without scatter correction, respectively. For the chest phantom, the ERMSEROI$E^{\text{ROI}}_{\text{RMSE}}$ in selected ROIs of VMIs is 12 HU for SMFFS CB scan, and 15 and 438 HU for sequential 80/140 kVp CB scan with and without scatter correction, respectively. Also, the non‐uniformity among selected regions of the chest phantom is 14 HU for SMFFS CB scan, and 59 and 184 HU for the DKV CB scan with and without a traditional scatter correction method, respectively. Conclusions: We propose a SDMD method for CBCT with SMFFS. Our preliminary results show that SMFFS can enable spectral imaging with simultaneous scatter correction for CBCT and effectively improve its quantitative imaging performance. [ABSTRACT FROM AUTHOR]

Background: Recent studies have shown a clear relationship between absorbed dose and tumor response to treatment after hepatic radioembolization. These findings help to create more personalized treatment planning and dosimetry. However, crucial to this goal is the ability to predict the dose distribution prior to treatment. The microsphere distribution is ultimately determined by (i) the hepatic vasculature and the resulting blood flow dynamics and (ii) the catheter position. Purpose: To show that pretreatment, intra‐procedural imaging of blood flow patterns, as quantified by catheter‐directed intra‐arterial contrast enhancement, correlate with posttreatment microsphere accumulation and, consequently, absorbed dose. Materials and methods: Patients who participated in a clinical trial (NCT01177007) and for whom both a pretreatment dual‐phase contrast‐enhanced cone‐beam CT (CBCT) and a posttreatment 90Y PET/CT scan were available were included in this retrospective study. Tumors and perfused volumes were manually delineated on the CBCT by an experienced radiologist. The mean, sum, and standard deviation of the voxels in each volume were recorded. The delineations were transferred to the PET‐based absorbed dose maps by coregistration of the corresponding CTs. Linear multiple regression was used to correlate pretreatment CBCT enhancement to posttreatment 90Y PET/CT‐based absorbed dose in each region. Leave‐one‐out cross‐validation and Bland–Altman analyses were performed on the predicted versus measured absorbed doses. Results: Nine patients, with a total of 23 tumors were included. All presented with hepatocellular carcinoma (HCC). Visually, all patients had a clear correspondence between CBCT enhancement and absorbed dose. The correlation between CBCT enhancement and posttherapy absorbed tumor dose based was strong (R2 = 0.91), and moderate for the non‐tumor liver tissue (R2 = 0.61). Limits of agreement were approximately ±55 Gray for tumor tissue. Conclusion: There is a linear relationship between pretreatment blood dynamics in HCC tumors and posttreatment absorbed dose, which, if shown to be generalizable, allows for pretreatment tumor absorbed dose prediction. [ABSTRACT FROM AUTHOR]

BACKGROUND: The application of miniscrew in adolescents is increasing day by day, but at present, there are few studies on bone mass in the external oblique line of the mandible in adolescents at home and abroad, and there is no systematic study on bone mass in the external oblique line of the mandible in adolescents in different growth and development periods. OBJECTIVE: To measure the bone mass in the external oblique line of the mandible in adolescents with different cervical vertebral bone ages using a conebeam CT and to investigate the difference of bone mass in the external oblique line of the mandible in adolescents with different cervical vertebral bone ages and the correlation between bone mass in this area and the cervical vertebral bone age. METHODS: The cone-beam CT data of 105 adolescent patients before orthodontic treatment were collected and divided into CS3 group (n=24), CS4 group (n=26), CS5 group (n=29) and CS6 group (n=26) using the cervical vertebral maturation method. The adolescent mandibular buccal shelf was reconstructed by Mimics Medical 21.0 software. The width of buccal bone at 6 and 11 mm under the cemento-enamel junction and the bone height at 4 and 5 mm buccal to the cemento-enamel junction of right mandibular first and second molars were measured. The measured data were statistically analyzed. The measurement was made on four planes: plane 1 is the plane where the proximal mesial root of the mandibular right first molar is located; plane 2 is the plane where the distal mesial root of the mandibular right first molar is located; plane 3 is the plane where the proximal mesial root of the mandibular right second molar is located; and plane 4 is the plane where the distal mesial root of the mandibular right second molar is located. RESULTS AND CONCLUSION: In each group, the bone width on the buccal side of the external oblique line increased gradually from the first molar proximally to the second molar distally in adolescents, and the width of buccal bone at 6 and 11 mm under the cemento-enamel junction showed significant difference among different layers (P < 0.05). The bone width of buccal bone at 11 mm under the cemento-enamel junction was greater than that at 6 mm. The bone height on the buccal side of the external oblique line increased gradually from the first molar proximally to the second molar distally in all four groups, and the bone height at 4 and 5 mm buccal to the cemento-enamel junction showed significant differences at different layers (P < 0.05). The bone height at 4 mm buccal to the cemento-enamel junction was greater than that at 5 mm. On the fourth plane, the bone width at 11 mm buccal to the cemento-enamel junction was smaller in the CS3, CS4, and CS5 groups than in the CS6 group (P < 0.05). On the third plane, the bone heights at 4 mm and 5 mm buccal to the cementoenamel junction were smaller in the CS3 and CS4 groups than in the CS6 group (P < 0.05). On the fourth plane, the bone height at 5 mm buccal to the cementoenamel junction was smaller in the CS3 and CS4 groups than in the CS6 group (P < 0.05). On the fourth plane, the bone height at 4 mm buccal to the cementoenamel junction was smaller in the CS3 group than in the CS6 group (P < 0.05). Spearman correlation analysis showed that there was no correlation between bone mass and the cervical vertebral bone age, except that there was a weak correlation between bone mass at some measurement sites and cervical vertebral bone age. To conclude, the bone mass in the external oblique area of the mandible in adolescents does not change significantly with the increase of cervical vertebral bone age. The buccal side of the mesial root and distal root of the mandibular second molar in the external oblique area of CS3-CS6 adolescents meets the requirement of bone mass for miniscrew implantation, which is a site available for miniscrew implantation. [ABSTRACT FROM AUTHOR]

Purpose: The present study is based on evidence indicating a potential correlation between cone-beam CT (CBCT) measurements of tumor size, shape, and the stage of locally advanced rectal cancer. To further investigate this relationship, the study quantitatively assesses the correlation between positioning CT (pCT) and CBCT in the radiomics features of these cancers, and examines their potential for substitution. Methods: In this study, 103 patients diagnosed with locally advanced rectal cancer and undergoing neoadjuvant chemoradiotherapy were selected as participants. Their CBCT and pCT images were used to divide the participants into two groups: a training set and a validation set, with a 7:3 ratio. An improved conventional 3D-RUNet (CLA-UNet) deep learning model was trained on the training set data and then applied to the validation set. The DSC, HD95 and ASSD were calculated for quantitative evaluation purposes. Then, radiomics features were extracted from 30 patients of the test set. Results: The experiments demonstrate that, the modified model achieves an average DSC score 0.792 for pCT and 0.672 for CBCT scans. 1037 features were extracted from each patient's CBCT and pCT images, 73 image features were found to have R values greater than 0.9, including three features related to the staging and prognosis of rectal cancer. Conclusion: In this study, we proposed an automatic, fast, and consistent method for rectal cancer GTV segmentation for pCT and CBCT scans. The findings of radiomic results indicate that CBCT images have significant research value in the field of radiomics. [ABSTRACT FROM AUTHOR]

Introduction: The investigation of peripheral pulmonary lesions (PPLs) can be challenging. Several bronchoscopic modalities have been developed to reach and biopsy PPL but the level of adoption of these techniques by interventional pulmonologists (IPs) is unknown. This international survey was conducted to describe current practices in PPL investigation among IP. Methods: This survey was sent to all members of the World Association for Bronchology and Interventional Pulmonology, Canadian Thoracic Society Procedures Assembly, AABIP, and the Groupe d'Endoscopie Thoracique et Interventionnel Francophone. The survey was composed of 48 questions and three clinical cases to establish a portrait of modalities used to investigate and treat PPL by IP around the world. Results: Three hundred and twelve IP responded to the survey. Most of them practice in Europe (n = 122), North America (n = 97), and Asia (n = 49). Half of responders perform more than 100 endoscopic procedures for PPL annually. General anesthesia and conscious sedation are used in similar proportions (53% and 47%, respectively). Rapid on site evaluation (ROSE) is used when sampling PPL by 42%. Radial EBUS (69%), fluoroscopy (55%), and electromagnetic navigation (27%) are the most widely used techniques. Most IP combine techniques (89%). Robotic bronchoscopy (15%) and cone-beam CT (8%) are almost exclusively used in the USA where, respectively, 60% and 37% of respondents reported using these modalities. Ten percent of IP currently had access to endoscopic treatment modalities for PPL. However, half of the remaining IP plan to acquire an endoscopic treatment modality in the next 2 years. Conclusion: Available techniques and practices worldwide vary significantly regarding PPL investigation and treatment. [ABSTRACT FROM AUTHOR]

Background: Dual‐energy (DE) detection of bone marrow edema (BME) would be a valuable new diagnostic capability for the emerging orthopedic cone‐beam computed tomography (CBCT) systems. However, this imaging task is inherently challenging because of the narrow energy separation between water (edematous fluid) and fat (health yellow marrow), requiring precise artifact correction and dedicated material decomposition approaches. Purpose: We investigate the feasibility of BME assessment using kV‐switching DE CBCT with a comprehensive CBCT artifact correction framework and a two‐stage projection‐ and image‐domain three‐material decomposition algorithm. Methods: DE CBCT projections of quantitative BME phantoms (water containers 100–165 mm in size with inserts presenting various degrees of edema) and an animal cadaver model of BME were acquired on a CBCT test bench emulating the standard wrist imaging configuration of a Multitom Rax twin robotic x‐ray system. The slow kV‐switching scan protocol involved a 60 kV low energy (LE) beam and a 120 kV high energy (HE) beam switched every 0.5° over a 200° angular span. The DE CBCT data preprocessing and artifact correction framework consisted of (i) projection interpolation onto matched LE and HE projections views, (ii) lag and glare deconvolutions, and (iii) efficient Monte Carlo (MC)‐based scatter correction. Virtual non‐calcium (VNCa) images for BME detection were then generated by projection‐domain decomposition into an Aluminium (Al) and polyethylene basis set (to remove beam hardening) followed by three‐material image‐domain decomposition into water, Ca, and fat. Feasibility of BME detection was quantified in terms of VNCa image contrast and receiver operating characteristic (ROC) curves. Robustness to object size, position in the field of view (FOV) and beam collimation (varied 20–160 mm) was investigated. Results: The MC‐based scatter correction delivered > 69% reduction of cupping artifacts for moderate to wide collimations (> 80 mm beam width), which was essential to achieve accurate DE material decomposition. In a forearm‐sized object, a 20% increase in water concentration (edema) of a trabecular bone‐mimicking mixture presented as ∼15 HU VNCa contrast using 80–160 mm beam collimations. The variability with respect to object position in the FOV was modest (< 15% coefficient of variation). The areas under the ROC curve were > 0.9. A femur‐sized object presented a somewhat more challenging task, resulting in increased sensitivity to object positioning at 160 mm collimation. In animal cadaver specimens, areas of VNCa enhancement consistent with BME were observed in DE CBCT images in regions of MRI‐confirmed edema. Conclusion: Our results indicate that the proposed artifact correction and material decomposition pipeline can overcome the challenges of scatter and limited spectral separation to achieve relatively accurate and sensitive BME detection in DE CBCT. This study provides an important baseline for clinical translation of musculoskeletal DE CBCT to quantitative, point‐of‐care bone health assessment. [ABSTRACT FROM AUTHOR]

Cone‐beam computed tomography (CBCT) system can provide real‐time 3D images and fluoroscopy images of the region of interest during the operation. Some systems can even offer augmented fluoroscopy and puncture guidance. The use of CBCT for interventional pulmonary procedures has grown significantly in recent years, and numerous clinical studies have confirmed the technology's efficacy and safety in the diagnosis, localization, and treatment of pulmonary nodules. In order to optimize and standardize the technical specifications of CBCT and guide its application in clinical practice, the consensus statement has been organized and written in a collaborative effort by the Professional Committee on Interventional Pulmonology of China Association for Promotion of Health Science and Technology. [ABSTRACT FROM AUTHOR]

Background and Purpose: There has been limited literature regarding the bridging veins (BVs) of the medulla oblongata around the foramen magnum (FM). The present study aims to analyze the normal angioarchitecture of the BVs around the FM using slab MIP images of three-dimensional (3D) angiography. Methods: We collected 3D angiography data of posterior fossa veins and analyzed the BVs around the FM using slab MIP images. We analyzed the course, outlet, and number of BVs around the FM. We also examined the detection rate and mean diameter of each BV. Results: Of 57 patients, 55 patients (96%) had any BV. The median number of BVs was two (range: 0–5). The BVs originate from the perimedullary veins and run anterolaterally to join the anterior condylar vein (ACV), inferior petrosal sinus, sigmoid sinus, or jugular bulb, inferolaterally to join the suboccipital cavernous sinus (SCS), laterally or posterolaterally to join the marginal sinus (MS), and posteriorly to join the MS or occipital sinus. We classified BVs into five subtypes according to the draining location: ACV, jugular foramen (JF), MS, SCS, and cerebellomedullary cistern (CMC). ACV, JF, MS, SCS, and CMC BVs were detected in 11 (19%), 18 (32%), 32 (56%), 20 (35%), and 16 (28%) patients, respectively. The mean diameter of the BVs other than CMC was 0.6 mm, and that of CMC BV was 0.8 mm. Conclusion: Using venous data from 3D angiography, we detected FM BVs in most cases, and the BVs were connected in various directions. [ABSTRACT FROM AUTHOR]

Background and purpose: Despite the superior dose conformity of proton therapy, the dose distribution is sensitive to daily anatomical changes, which can affect treatment accuracy. This study evaluated the dose recalculation accuracy of two synthetic computed tomography (sCT) generation algorithms in a commercial treatment planning system. Materials and methods: The evaluation was conducted for head-and-neck, thorax-and-abdomen, and pelvis sites treated with proton therapy. Thirty patients with two cone-beam computed tomography (CBCT) scans each were selected. The sCT images were generated from CBCT scans using two algorithms, Corrected CBCT (corrCBCT) and Virtual CT (vCT). Dose recalculations were performed based on these images for comparison with “ground truth” deformed CTs. Results: The choice of algorithm influenced dose recalculation accuracy, particularly in high dose regions. For head-and-neck cases, the corrCBCT method showed closer agreement with the “ground truth”, while for thorax-and-abdomen and pelvis cases, the vCT algorithm yielded better results (mean percentage dose discrepancy of 0.6 %, 1.3 % and 0.5 % for the three sites, respectively, in the high dose region). Head-and-neck and pelvis cases exhibited excellent agreement in high dose regions (2 %/2 mm gamma passing rate >98 %), while thorax-and-abdomen cases exhibited the largest differences, suggesting caution in sCT algorithm usage for this site. Significant systematic differences were observed in the clinical target volume and organ-at-risk doses in head-and-neck and pelvis cases, highlighting the importance of using the correct algorithm. Conclusions: This study provided treatment site-specific recommendations for sCT algorithm selection in proton therapy. The findings offered insights for proton beam centers implementing adaptive radiotherapy workflows.

PurposeTo describe the technique and document utility of adjunctive cone-beam CT (CBCT) in patients undergoing bronchial artery embolization (BAE) or chemoinfusion (BAC).Materials and methodsBetween August 2010 and February 2021, 26 patients (62 bronchial arteries) were evaluated with CBCT in addition to the usual digital subtraction angiography (DSA) during BAE or BAC. 19 patients (43 arteries) underwent BAE for hemoptysis; 7 patients (19 arteries) had BAC for palliation of lung malignancy. Retrospective review of procedural reports and the archived DSA and CBCT images was assessed for (1) whether CBCT findings added unique diagnostic information prior to treatment of target arteries compared to DSA alone; and (2) whether these unique CBCT findings led to modification of embolization or chemoinfusion technique.ResultsIn 61 of 62 (98%) interrogated bronchial arteries, CBCT provided additional unique diagnostic information over planar DSA, primarily cross-sectional assessment of the spinal canal for spinal arteries. In 46/62 (74%) of the bronchial arteries the unique information did not lead to a change in therapeutic technique. In 15 bronchial arteries (24%), the added information from CBCT led to change in embolization and/or chemoinfusion technique. Embolization of one small unrecognized spinal artery branch (1.6%), which was missed intra-procedurally but retrospectively seen on CBCT led to transient spinal cord ischemia.ConclusionsThese results suggest that adjunctive use of CBCT technique may improve diagnostic confidence from information provided by DSA in nearly all cases of BAE and BAC leading to improved therapeutic targeting or change in technique of embolization or chemoinfusion.

Abstract Background Cone-beam computed tomography (CBCT) has been introduced for breast-specimen imaging to identify a free resection margin of abnormal tissues in breast conservation. As well-known, typical micro CT consumes long acquisition and computation times. One simple solution to reduce the acquisition scan time is to decrease of the number of projections, but this method generates streak artifacts on breast specimen images. Furthermore, the presence of a metallic-needle marker on a breast specimen causes metal artifacts that are prominently visible in the images. In this work, we propose a deep learning-based approach for suppressing both streak and metal artifacts in CBCT. Methods In this work, sinogram datasets acquired from CBCT and a small number of projections containing metal objects were used. The sinogram was first modified by removing metal objects and up sampling in the angular direction. Then, the modified sinogram was initialized by linear interpolation and synthesized by a modified neural network model based on a U-Net structure. To obtain the reconstructed images, the synthesized sinogram was reconstructed using the traditional filtered backprojection (FBP) approach. The remaining residual artifacts on the images were further handled by another neural network model, ResU-Net. The corresponding denoised image was combined with the extracted metal objects in the same data positions to produce the final results. Results The image quality of the reconstructed images from the proposed method was improved better than the images from the conventional FBP, iterative reconstruction (IR), sinogram with linear interpolation, denoise with ResU-Net, sinogram with U-Net. The proposed method yielded 3.6 times higher contrast-to-noise ratio, 1.3 times higher peak signal-to-noise ratio, and 1.4 times higher structural similarity index (SSIM) than the traditional technique. Soft tissues around the marker on the images showed good improvement, and the mainly severe artifacts on the images were significantly reduced and regulated by the proposed. method. Conclusions Our proposed method performs well reducing streak and metal artifacts in the CBCT reconstructed images, thus improving the overall breast specimen images. This would be beneficial for clinical use.

PURPOSETo compare tumor perfusion on cone-beam computed tomography (CBCT) after hepatic artery infusion port implantation with the tumor response to hepatic arterial infusion chemotherapy (HAIC) in patients with hepatocellular carcinoma (HCC).METHODSThis retrospective study was conducted in patients with advanced HCC treated with HAIC from 2015 to 2020. We performed CBCT with contrast injection via a port on the day following implantation. We classified tumor perfusion on CBCT into three groups: hyperperfusion, isoperfusion, and hypoperfusion. We also evaluated tumor response to HAIC on follow-up images using RECIST 1.1 and compared it with tumor perfusion on CBCT.RESULTSThis study included 206 tumors in 193 patients (mean: 60.5 years) with HCC. There were 100 hyperperfusion tumors (48.5%), 92 isoperfusion tumors (44.7%), and 14 hypoperfusion tumors (6.8%). The tumor response to HAIC included 10 tumors with a complete response (CR) (4.9%), 66 tumors with a partial response (32%), 60 tumors with stable disease (29.1%), and 70 tumors with progressive disease (34%). Hyperperfusion tumors had a 65% objective response rate (ORR) and a 92% disease control rate (DCR). Isoperfusion tumors had a 12% ORR and a 46.8% DCR, while hypoperfusion tumors had a 0% ORR and a 7.1% DCR. A CR was shown only in hyperperfusion tumors. The ORR and DCR of the three groups were different, with statistical significance (P < 0.001).CONCLUSIONHyperperfusion tumors on CBCT showed a better tumor response to HAIC, with a 65% ORR in patients with HCC. Tumor perfusion on CBCT after implantation of the hepatic arterial infusion port was associated with the tumor response to HAIC.

Abstract Introduction The ability to capture more anatomical detail in cone‐beam computed tomography (CBCT) imaging compared to kilovoltage (kV) and megavoltage (MV) imaging, has seen a documented shift towards CBCT image verification and staff adopting more extensive image analysis processes. The timeframe associated with assessing online CBCT images, termed the online decision analysis time, if drawn out, can affect treatment efficiency and accuracy. This study aimed to determine the current CBCT online decision analysis time at Radiation Oncology Princess Alexandra Ipswich Road (ROPAIR) and investigate the influence of isocentre shift magnitude and treatment site considerations on this timeframe. Methods This retrospective clinical audit collected treatment parameters from 202 CBCT images over 2 treatment days. The online decision analysis time was calculated by subtracting the image acquisition timestamp from the image verification shift application timestamp. The quantitative data were analysed using mean, standard deviation, and range in the following categories: all CBCTs, CBCTs grouped by isocentre shift magnitude and CBCTs grouped by treatment site. Content analysis was performed on staff comments made during image analysis. Results The average online decision analysis time was 2:37 ± 1:28 min. On average approximately, head and neck, spine and extremity treatment sites measured 1 min, pelvis, breast, and chest measured 2–3 min with abdomen measuring 4 min. Common categories reported in staff comments included anatomical changes, repositioning, and organs at risk size. Conclusion The results provide baseline online decision analysis times. Further refinement is required to determine if the image match method, treatment site considerations, and rotational discrepancies influence this timeframe.

Objectives: This study aims to investigate the use of sodium iodide (NaI), dimethyl sulfoxide (DMSO), ethyl alcohol, and ethyl acetate as cone-beam CT (CBCT) contrast agents for diagnosing cracked teeth. The optimal delay time for detecting the number of crack lines beyond the dentino-enamel junction (Nd), the number of cracks extending from the occlusal surface to the pulp cavity (Np), and the depth of the crack lines was explored. Methods: 14 human extracted cracked teeth were collected, 12 were used for enhanced scanning, and 2 were used for exploring the characteristic of crack lines. The teeth were scanned in 3 CBCT enhanced scanning (ES) modes: ES1 using meglumine diatrizoate (MD); ES2 using NaI and DMSO, ES3 using NaI, DMSO, ethyl alcohol and ethyl acetate. Three delay times (15mins, 30mins, and 60mins) were set for scanning. Nd, Np, and depth of crack lines were evaluated. Results: There were totally 24 crack lines on 12 cracked teeth. Nd was 10 in ES1 at 60mins, 24 in ES2 at 60mins and 24 in ES3 at 15mins. Np was 1 in ES1 at 60mins, 10 in ES2 at 60mins and 21 in ES3 at 60mins, and there were significantly different among them (p