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2,969 result(s) for "COMPUTERIZED TOMOGRAPHY"
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Implant Restorations
The fourth edition of Implant Restorations: A Step-by-Step Guide provides a wealth of updated and expanded coverage on detailed procedures for restoring dental implants. Focusing on the most common treatment scenarios, it offers concise literature reviews for each chapter and easy-to-follow descriptions of the techniques, along with high-quality clinical photographs demonstrating each step.  Comprehensive throughout, this practical guide begins with introductory information on incorporating implant restorative dentistry in clinical practice. It covers diagnosis and treatment planning and digital dentistry, and addresses advances in cone beam computerized tomography (CBCT), treatment planning software, computer generated surgical guides, rapid prototype printing and impression-less implant restorative treatments, intra-oral scanning, laser sintering, and printing/milling polymer materials. Record-keeping, patient compliance, hygiene regimes, and follow-up are also covered.  * Provides an accessible step-by-step guide to commonly encountered treatment scenarios, describing procedures and techniques in an easy-to-follow, highly illustrated format * Offers new chapters on diagnosis and treatment planning and digital dentistry * Covers advances in cone beam computerized tomography (CBCT), computer generated surgical guides, intra-oral scanning, laser sintering, and more  An excellent and accessible guide on a burgeoning subject in modern dental practice by one of its most experienced clinicians, Implant Restorations: A Step-by-Step Guide, Fourth Edition will appeal to prosthodontists, general dentists, implant surgeons, dental students, dental assistants, hygienists, and dental laboratory technicians.
Diagnostic value of SPECT/CT examinations with particular emphasis on the skeletal system
Hybrid devices are increasingly used in nuclear medicine diagnostics. They enable molecular imaging (single photon emission computerized tomography – SPECT) of pathological changes in the body. It is necessary to refine the parameters of image acquisition and reconstruction, as well as to formulate clinical recommendations for hybrid SPECT/computed tomography (CT) examinations. Therefore, this study aimed to investigate the diagnostic usefulness of SPECT/CT examinations using a hybrid gamma camera, with particular emphasis on skeletal scintigraphy. This work attempts to address this question.
Radiomics model of dual-time 2-18FFDG PET/CT imaging to distinguish between pancreatic ductal adenocarcinoma and autoimmune pancreatitis
Objectives Pancreatic ductal adenocarcinoma (PDAC) and autoimmune pancreatitis (AIP) are diseases with a highly analogous visual presentation that are difficult to distinguish by imaging. The purpose of this research was to create a radiomics-based prediction model using dual-time PET/CT imaging for the noninvasive classification of PDAC and AIP lesions. Methods This retrospective study was performed on 112 patients (48 patients with AIP and 64 patients with PDAC). All cases were confirmed by imaging and clinical follow-up, and/or pathology. A total of 502 radiomics features were extracted from the dual-time PET/CT images to develop a radiomics decision model. An additional 12 maximum intensity projection (MIP) features were also calculated to further improve the radiomics model. The optimal radiomics feature set was selected by support vector machine recursive feature elimination (SVM-RFE), and the final classifier was built using a linear SVM. The performance of the proposed dual-time model was evaluated using nested cross-validation for accuracy, sensitivity, specificity, and area under the curve (AUC). Results The final prediction model was developed from a combination of the SVM-RFE and linear SVM with the required quantitative features. The multimodal and multidimensional features performed well for classification (average AUC: 0.9668, accuracy: 89.91%, sensitivity: 85.31%, specificity: 96.04%). Conclusions The radiomics model based on 2-[ 18 F]fluoro-2-deoxy-D-glucose (2-[ 18 F]FDG) PET/CT dual-time images provided promising performance for discriminating between patients with benign AIP and malignant PDAC lesions, which shows its potential for use as a diagnostic tool for clinical decision-making. Key Points • The clinical symptoms and imaging visual presentations of PDAC and AIP are highly similar, and accurate differentiation of PDAC and AIP lesions is difficult. • Radiomics features provided a potential noninvasive method for differentiation of AIP from PDAC. • The diagnostic performance of the proposed radiomics model indicates its potential to assist doctors in making treatment decisions .
Efficacy of Automatic 3D Segmentation of the Upper Airway in CBCT or CT Scans via Artificial Intelligence Versus Manual Segmentation by Human Experts: A Systematic Review and Meta‐Analysis
Objectives 3D segmentation of the upper airway is crucial for dental and medical practices. However, it is a difficult and daunting task. Like almost all other areas, AI can theoretically help in airway segmentation. Nevertheless, AI's efficacy remains unknown. This meta‐analysis investigated this matter for the first time. Material and Methods ‎Various search engines/databases/articles were searched for articles published until April 25, 2025. All English‐language articles on the use of AI for upper airway evaluations based on CBCT or CT scans were included in the study. The desired population was considered studies assessing the upper airway. Intervention was the use of any tool of AI such as deep learning and machine learning for image analysis. The comparator was the manual analysis of CBCT or CT scans by human. The outcome was the analysis of upper airway on CBCT or CT images. The recorded and analyzed effect sizes were: accuracies, precisions, dice similarity scores, total volume differences, intersection over union (IoU), recall, or any other parameters relevant to segmentation. A meta‐analysis was conducted for each of the mentioned parameters if adequate data were available. The outcome was the analysis of upper airway on CBCT or CT images (PROSPERO: CRD42024508004). Results Eleven studies were included, with 6 studies included in meta‐analyses. Most studies had a low risk of bias in most aspects. The qualitative part of review showed promising results for AI segmentation. Four of the effects sizes were meta‐analyzed: Precision,‎ dice similarity score, intersection over union, ‎ and recall were all above 90%.‎ Total volume difference was small but significantly above zero. Sensitivity analyses showed robustness of all meta‐analysis results. Publication bias was insignificant. Conclusions The results showed promising AI efficacies in 3D segmentation of the upper airway in CBCTs. However, much more studies are needed before decisive conclusions.
Fluorodeoxyglucose positron emission tomography-computerized tomography scan in LGI A1-positive limbic encephalitis and concordance with MRI in a known case of carcinoma breast
The limbic encephalitis is an autoimmune disorder which characterized by inflammation of the brain with rapidly progressing dementia either due to paraneoplastic or nonparaneoplastic etiology which requires definitive neurological and whole-body evaluation. We describe both clinical and nuclear medicine imaging and radiological findings in a case of limbic encephalitis using positron emission tomography and magnetic resonance imaging.
Appropriateness criteria of FDG PET/CT in oncology
Abstract 18Fluorine-2-fluoro-2-Deoxy-d-glucose (18 F-FDG) positron emission tomography/computerized tomography (PET/CT) is a well-established functional imaging method widely used in oncology. In this article, we have incorporated the various indications for18 FDG PET/CT in oncology based on available evidence and current guidelines. Growing body of evidence for use of18 FDG PET/CT in select tumors is also discussed. This article attempts to give the reader an overview of the appropriateness of using18 F-FDG PET/CT in various malignancies.
Downregulated GPR30 expression in the epileptogenic foci of female patients with focal cortical dysplasia type IIb and tuberous sclerosis complex is correlated with 18F‐FDG PET‐CT values
Focal cortical dysplasia type IIb (FCDIIb) and tuberous sclerosis complex (TSC) are typical causes of developmental delay and refractory epilepsy. G‐protein‐coupled receptor 30 (GPR30) is a specific estrogen receptor that is critical in neurodevelopment, neuroinflammation, and neuronal excitability, suggesting that it plays a potential role in the epilepsy of patients with FCDIIb and TSC. Therefore, we investigated the role of GPR30 in patients with FCDIIb and TSC. We found that the expression of GPR30 and its downstream protein kinase A (PKA) pathway were decreased and negatively correlated with seizure frequency in female patients with FCDIIb and TSC, but not in male patients. GPR30 was widely distributed in neurons, astrocytes, and microglia, and its downregulation was especially notable in microglia. The GPR30 agonist G‐1 increased the expression of PKA and p‐PKA in cultured cortical neurons, and the GPR30 antagonist G‐15 exhibited the opposite effects of G‐1. The NF‐κB signaling pathway was also activated in the specimens of female patients with FCDIIb and TSC, and was regulated by G‐1 and G‐15 in cultured cortical neurons. We also found that GPR30 regulated cortical neuronal excitability by altering the frequency of spontaneous excitatory postsynaptic currents and the expression of NR2A/B. Further, the relationship between GPR30 and glycometabolism was evaluated by analyzing the correlations between GPR30 and 18F‐FDG PET‐CT values (standardized uptake values, SUVs). Positive correlations between GPR30 and SUVs were found in female patients, but not in male patients. Intriguingly, GPR30 expression and SUVs were significantly decreased in the epileptogenic tubers of female TSC patients, and ROC curves indicated that SUVs could predict the localization of epileptogenic tubers. Taken together, our results suggest a potential protective effect of GPR30 in the epileptogenesis of female patients with FCDIIb and TSC.
Extrapancreatic insulinoma
Abstract A 38-year-old female presented with recurrent episodes of hypoglycemia for 5 years. On 72-h fast test, critical sample biochemistry was suggestive of endogenous hyperinsulinemic hypoglycemia. Both constrast-enhanced computed tomography and 68 Ga-DOTATATE positron emission tomography/computerized tomography (PET/CT) revealed no pancreatic lesion but showed a jejunal lesion suggestive of neuroendocrine tumor (NET) but not confirmatory of insulinoma. 68 Ga-Exendin-4 PET/CT showed intense uptake in the proximal jejunum, and this being a specific scan for insulinoma, confirmed it as an ectopic insulinoma. The patient attained normoglycemia after excision of this NET confirming it to be a case of ectopic insulinoma located in the jejunum. Although most insulinomas are located in the pancreas, rarely ectopic cases have been described in the spleen, perisplenic tissue, duodenohepatic ligament, adjacent to the ligament of Treitz, duodenum, and the jejunum. Functional scanning with 68 Ga-Exendin-4 PET/CT scan aids the localization of ectopic insulinoma.
The value of complete remission according to positron emission tomography prior to autologous stem cell transplantation in lymphoma: a population-based study showing improved outcome
Background Chimeric antigen-receptor T-cell and bispecific antibody therapies will likely necessitate a reconsideration of the role of autologous stem-cell transplantation (ASCT) in lymphoma. Patients who are likely to profit from ASCT need to be better identified. Methods Here, we investigated the value of positron emission tomography/computerized tomography (PET/CT) before ASCT. All 521 patients transplanted for lymphoma 1994–2019 at Karolinska (497 conditioned with BEAM) were included. Results Outcome improved over three calendar periods 1994–2004, 2005–2014, 2015–2019 (2-year overall survival [OS]: 66, 73, 83%; P  = 0.018). Non-relapse mortality (NRM) at 100 days over the three periods were 9.8, 3.9, 2.9%, respectively. The OS improvement between 1994 and 2004 and 2005–2014 was due to lower NRM ( P  = 0.027), but the large OS advance from 2015 was not accompanied by a significant reduction in NRM ( P  = 0.6). The fraction of PET/CT as pre-ASCT assessment also increased over time: 1994–2004, 2%; 2005–2014, 24%; 2015–2019, 60% ( P  < 0.00005). Complete responses (PET/CT-CR) were observed in 77% and metabolically active partial responses (PET/CT-PR) in 23%. PET/CT-CR was a predictor for survival in the entire population ( P  = 0.0003), also in the subpopulations of aggressive B-cell ( P  = 0.004) and peripheral T-cell ( P  = 0.024) lymphomas. Two-year OS and progression-free survival (OS/PFS) for patients in PET/CT-CR were in relapsed/refractory aggressive B-cell lymphoma 87%/75% and peripheral T-cell lymphoma 91%/78%. The corresponding figures in PET/CT-PR were 43%/44 and 33%/33%. Patients with solitary PET/CT-positive lesions showed acceptable outcome with ASCT followed by local irradiation (2-year OS/PFS 80%/60%). CT was less discriminative: 2-year OS/PFS: CT-CR, 76%/66%; CT-PR, 62%/51%. Outcome was inferior after BEAC compared with BEAM conditioning. Conclusions We conclude that the improved outcome reflects better, PET/CT-informed, identification of patients who should proceed to ASCT. The excellent survival of patients in PET/CT-CR indicates that ASCT should remain part of standard therapy for lymphoma.
The characteristics of chest HRCT and pulmonary function tests in lung‐onset primary sjogren's syndrome
Introduction Interstitial lung disease (ILD) can manifest before the diagnosis of primary Sjögren's syndrome (pSS), however, the underlying mechanisms remain unclear. The aim of this study is to investigate the characteristics of lung‐onset pSS using chest high‐resolution computerized tomography (HRCT) and pulmonary function tests (PFTs). Methods The data of 102 patients with pSS‐ILD were retrospectively analyzed. The patients were divided into two groups: lung‐onset group and the nonlung‐onset group. The chest HRCT, PFTs, and clinical and laboratory data were evaluated and compared. Results Among the 102 patients with pSS‐ILD, 59 (57.8%) were lung‐onset and 43 (42.2%) were nonlung‐onset. Chest HRCT in the lung‐onset group showed higher percentage of usual interstitial pneumonia and nonspecific interstitial pneumonia, the difference did not reach statistical significance. The total HRCT score was higher in the lung‐onset group, compared with the nonlung‐onset group (2 [2, 3], vs. 2 [1, 2], p = .014). Total lung capacity (TLC) (%pred) [(75.4 ± 16.2) versus (82.8 ± 19.4), p = .049] and forced vital capacity (FVC) (%pred) [(82.2 ± 19.9) versus (91.6 ± 28.3), p = .050] were significantly lower in the lung‐onset group, compared with the nonlung‐onset group. Residual volume (RV)/TLC (%) significantly increased more than 40% in the lung‐onset group (p = .015). Restricted ventilation disorder, small airway obstruction and reduced diffusing capacity of the lung for carbon monoxide/alveolar volume (%Pred) were more common in the lung‐onset group (p = .038, p = .050, and p = .050, respectively). Correlation analysis showed that HRCT score was positively correlated with the interval between the onset of pulmonary symptoms and the diagnosis of ILD, serum CA125, and serum CEA. TCL (%pred), VC (%pred), FVC (%pred) were negatively correlated with serum CA125. Conclusion Lung‐onset is common in pSS patients with more severe lung function impairments. Serum biomarkers, such CA125, CEA, and ALB, were associated with the severity of lung damage. Lung‐onset is common in primary Sjögren's syndrome patients, and these patients present with more severe lung function impairments. Serum biomarkers, such CA125, CEA, and ALB were associated with the degree of lung damage.