Accuracy of artificial bone defects measurements on two cone beam computed tomography scanners. A comparative study

Introduction: Several CBCT systems are currently on the market variable in their image quality and ability to visualize anatomic structures. Those systems differ from each other in detector design, patient scanning settings, and data reconstruction parameters. Moreover, other scanning and reconstruction factors including scan field of view (FOV), voxel size and the number of basis projections used for reconstruction have significant influence on image quality in CBCT. The aim of this study is to compare two CBCT systems regarding their linear measurements accuracy. Materials and methods: Eighteen bone defects were created in one dry skull by using a round diamond bur mounted on a high speed hand piece. The defects were fully injected with polyvinyl siloxane impression. The skull was scanned using Planmeca ProMax 3D (Planmeca, Helsinki, Finland) and i-CAT next generation (Imaging Sciences international, Hatfield, PA, USA). Images were uploaded to a third party software (On Demand, Cyber med Inc. South Korea) for applying the measurements. Several measurements of each rubber impression material were done using the measurement tool on the cross sectional images in order to determine the maximum diameter. Then the impression material was removed carefully from the mandible by a dental probe and all the rubber balls were measured with a digital caliber to determine the actual maximum diameter (gold standard). Numerical collected data were explored for normality by checking the data distribution. Results: The results of the present study showed that the overall measurements by Planmeca showed statistically significantly higher mean measurement than the standard reference while i-CAT measurements showed nonstatistically significant difference from the standard reference at all areas and also regarding the overall measurement. Regarding the overall error measurement and error percentage; Planmeca showed statistically significantly higher mean error and error percentage than I-CAT. Conclusion: CBCT is highly accurate and reproducible in linear measurements in the axial and coronal image planes and in different areas of the maxillofacial region. According to the findings of the present study I-CAT is recommended when the purpose of the CBCT scan is to measure linear distances. This will result in lower patient radiation dose and faster scan time

VALIDITY OF CONE BEAM COMPUTED TOMOGRAPHY VOXEL DENSITY VALUES: A REVIEW.

Introduction: voxel density value in CBCT is used regularly in many clinical aspects such as virtual implant planning. Many researchers studied factors affecting it and their significance. Most of the results obtained are contradicting and /or inconclusive. Objectives: to compile papers inquiring effect factors affecting voxel grey values and their significance. Methodology: internet search was done on two databases using MeSH terms. Resulting studies went through two level screening according to predetermined inclusion and exclusion criteria. Results: A total of 27 studies were included. Total number of factors, which were tested in the included papers, were eighteen. Conclusion:Significantly affecting factors are (FOV, mA, Objects position inside the FOV, Objects exo-mass, kVp, time between exposure, number of basis, adjacent air to the ROI).Insignificantly affecting factors are (exposure parameters, software, exposure dose, presence of teeth, presence of metallic post in or out the FOV). Inconclusive factors are (Machines model, voxel size, objects mass, receptor type, exposure time). Grey levels in CBCT which is known by Hounsfield Unit of CBCT is not reliable nor repeatable

Detection of simulated vertical root fractures; which is better multi-detector computed tomography or cone beam computed tomography?

Objectives: Multi-detector computed tomography (MDCT) and cone beam computed tomography (CBCT) were compared regarding their ability to detect vertical root fractures. Methods: Sixty four extracted posterior teeth were included in this study. Using a diamond disc, thirty six teeth were cut vertically to simulate a VRF. Twenty eight teeth were used as control. Fractured and non-fractured teeth were randomly positioned in 4 skulls and mandibles. Scanning was performed first on a 16 slice Siemens MDCT, then by i-CAT Next Generation CBCT. Two observers assessed the multiplanar images for vertical root fractures using a 3-point scale. The first observer repeated the assessment after 1 week. Later, the 2 observers re-assessed the images together to reach a consensus score. Results: CBCT showed higher sensitivity, accuracy as well as negative predictive value compared to MDCT. The mean area under the curve was 0.917 for MDCT and 0.972 for CBCT. The difference in diagnostic accuracy between the 2 modalities was statistically significant P = .036. Inter-observer agreement was 0.971 for MDCT and 0.994 for CBCT, whereas intra-observer agreement was 0.981 for MDCT and 0.985 for CBCT. Conclusion: Using the specified scanners at the specified exposure parameters, the diagnostic accuracy of CBCT in detecting vertical root fractures was significantly higher than MDCT. Keywords: Multi-detector computed tomography, Cone-beam computed tomography, Root fractur

Accuracy of Diffusion Weighted Magnetic Resonance Imaging in Differentiation between Malignant and Non-malignant Maxillofacial Lesions

Objectives: to evaluate the signal characteristics of Diffusion Weighted Magnetic Resonance Imaging (DWMRI) of maxillofacial intraosseous lesions and their corresponding apparent diffusion coefficient (ADC) values and assess their ability to differentiate between malignant and non-malignant lesions. Methods: This study included 17 patients (10 males and 7 females) selected from the outpatients’ clinic of Oral Surgery Department, Faculty of Dentistry, Ain-shams University. They were examined by MRI machine; Philips 1.5 Tesla Achieva, Netherlands using DWMRI, T1 and T2 sequences and ADC values were measured. Results: There was a statistically significant difference between T1 signal distributions among patients with benign and malignant lesions (P-value = 0.027, Effect size = 0.685). Benign lesions showed higher prevalence of low and high signals while malignant lesions showed higher prevalence of intermediate signal. There was a statistically significant difference between T2 signal distributions among patients with benign and malignant lesions (P-value = 0.029, Effect size = 0.609). Benign lesions showed higher prevalence of high signal while malignant lesions showed higher prevalence of intermediate signal. ROC curve analysis showed a cut-off value of (≤ 1 ´10-3 mm2) with diagnostic accuracy of 94.1%, a sensitivity of 100% and specificity of 91.7% indicating that ADC values less than or equal to 1 ´10-3 mm2 indicate malignant lesion and values greater than 1 ´10-3 mm2 indicate benign lesion (P-value Conclusion: DWMRI is highly accurate in the differentiation between benign and malignant intraosseous lesions of the jaws

Corrosion inhibition of mild steel in 1 M HCl by pyrazolone-sulfonamide hybrids: synthesis, characterization, and evaluation

Abstract Carbon steel is widely used in the petroleum industry for pipelines, storage tanks, and equipment due to its mechanical properties, and strength. However, challenges such as environmental conditions and corrosive materials can affect its lifespan and require maintenance and repair. This work aimed to prepare pyrazalone-sulfonamide hybrids, and confirmed by mass spectra, FTIR, 1H-NMR, and 13C-NMR. These compounds were examined as mild steel corrosion inhibitors in 1 M HCl solutions at 298–323 K using the gravimetric technique, electrochemical measurements, scanning electronic microscope analysis, and quantum chemical calculations. The values of inhibitory efficiency identified by electrochemical and non-electrochemical techniques exhibit good agreement. At various temperatures and in the 50 to 500 ppm concentration range. During the adsorption process, these substances connect to the Langmuir adsorption isotherm. Some adsorption isotherm and kinetic parameters have been developed and discussed. The metal surface had a thin inhibitory protective layer, according to investigations using energy dispersive X-ray spectroscopy (EDX) and scanning electron microscope (SEM). These findings demonstrated the potential of pyrazolone-sulfonamide as effective organic corrosion inhibitors for carbon steel

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)