Mean Gray Value Research Articles

Combination of 18F-FDG PET/CT and convex probe endobronchial ultrasound elastography for intrathoracic malignant and benign lymph nodes prediction.

BackgroundPositron emission tomography–computed tomography (PET/CT) and convex probe endobronchial ultrasound (CP-EBUS) elastography are important diagnostic methods in predicting intrathoracic lymph nodes (LNs) metastasis, but a joint analysis of the two examinations is still lacking. This study aimed to compare the diagnostic efficiency of the two methods and explore whether the combination can improve the diagnostic efficiency in differentiating intrathoracic benign LNs from malignant LNs.Materials and MethodsLNs examined by EBUS-guided transbronchial needle aspiration (EBUS-TBNA) and PET/CT from March 2018 to June 2019 in Shanghai Chest Hospital were retrospectively analyzed as the model group. Four PET/CT parameters, namely, maximal standardized uptake value mean standardized uptake value (SUVmean), SUVmean, metabolic tumor volume (MTV), and tumor lesion glycolysis (TLG); four quantitative elastography indicators (stiff area ratio, mean hue value, RGB, and mean gray value); and the elastography grading score of targeted LNs were analyzed. A prediction model was constructed subsequently and the dataset from July to November 2019 was used to validate the diagnostic capability of the model.ResultsA total of 154 LNs from 135 patients and 53 LNs from 47 patients were enrolled in the model and validation groups, respectively. Mean hue value and grading score were independent malignancy predictors of elastography, as well as SUVmax and TLG of PET/CT. In model and validation groups, the combination of PET/CT and elastography demonstrated sensitivity, specificity, positive and negative predictive values, and accuracy for malignant LNs diagnosis of 85.87%, 88.71%, 91.86%, 80.88%, and 87.01%, and 94.44%, 76.47%, 89.47%, 86.67%, and 88.68%, respectively. Moreover, elastography had better diagnostic accuracies than PET/CT in both model and validation groups (85.71% vs. 79.22%, 86.79% vs. 75.47%).ConclusionEBUS elastography demonstrated better efficiency than PET/CT and the combination of the two methods had the best diagnostic efficacy in differentiating intrathoracic benign from malignant LNs, which may be helpful for clinical application.

Fabrication of a clavicle phantom for radiography using hydrated lime

Epidemiological studies indicate that clavicle fractures are predominant, particularly in men. Hydrated lime was found to be a suitable substance to mimic the bone composition. It is durable and has a good X-ray image intensity compared with that of a real bone. In contrast, silicone exhibits an X-ray diffraction spectrum similar to that of soft tissues. In this paper, phantoms with different sites of clavicle fractures were fabricated using hydrated lime, for education and quality assurance purposes. Phantoms with different pathologies of the left clavicle were fabricated via a multi-step technique. The clavicle phantoms were broken at different sites, representing most fractures reported in the literature. The clavicle phantom was radiographed along with the real clavicle bone using an X-ray machine (Definium 6000, General electric, 2009) with imaging parameters of 53 kV, 100 mA, and 1.2 mAs. This was performed to compare their structures and densities. The resulting mean grey values were 243.03, 248.97, and 253.53 for the real bone, bone fabricated using hydrated lime, and fabricated bone coated with silicone, respectively. This indicates a contrast of 0.02 between the real and fabricated bones and a contrast of 0.04 between the real and fabricated bones coated with silicone. Similar effective atomic number between bone and lime and low contrast values between the real bone and fabricated phantoms support the possibility of successful fabrication of clavicle phantoms using hydrated lime, for the purposes of education and quality assurance.

Quantitative susceptibility-weighted imaging in presence of strong susceptibility sources: Application to hemorrhage

PurposeTo optimize quantitative susceptibility-weighted imaging also known as true susceptibility-weighted imaging (tSWI) for strong susceptibility sources like hemorrhage and compare to standard susceptibility-weighted imaging (SWI) and quantitative susceptibility mapping (QSM). MethodsTen patients with known intracerebral hemorrhage (ICH) were scanned using a 3D SWI sequence. The magnitude and phase images were utilized to compute QSM, tSWI and SWI images. tSWI parameters including the upper threshold for creating susceptibility-weighted masks and the multiplication factor were optimized for hemorrhage depiction. Combined tSWI was also computed with independent optimized parameters for both veins and hemorrhagic regions. tSWI results were compared to SWI and QSM utilizing region-of-interest measurements, Pearson's correlation and Kruskal-Wallis test. ResultsFifteen hemorrhages were found, with mean susceptibility 0.81 ± 0.37 ppm. Unlike SWI which utilizes a phase mask, tSWI uses a mask computed from QSM. In tSWI, the weighted mask required an extended upper threshold far beyond the standard level for more effective visualization of hemorrhage texture. The upper threshold was set to the mean maximum susceptibility in the hemorrhagic region (3.24 ppm) with a multiplication factor of 2. The blooming effect, seen in SWI, was observed to be larger in hemorrhages with higher susceptibility values (r = 0.78, p < 0.001) with reduced blooming on tSWI. On SWI, 4 out of 15 hemorrhages showed phase wrap artifacts in the hemorrhagic region and all patients showed some phase wraps in the air-tissue interface near the auditory and frontal sinuses. These phase wrap artifacts were absent on tSWI. In hemorrhagic regions, a higher correlation was observed between the actual susceptibility values and mean gray value for tSWI (r = −0.93, p < 0.001) than SWI (r = −0.87, p < 0.001). ConclusionIn hemorrhage, tSWI minimizes both blooming effects and phase wrap artifacts observed in SWI. However, unlike SWI, tSWI requires an altered upper threshold for best hemorrhage depiction that greatly differs from the standard value. tSWI can be used as a complementary technique for visualizing hemorrhage along with SWI.

A fluorescence imaging-supported aptasensor for sensitive monitoring of cadmium pollutant in diverse samples: A critical role of metal organic frameworks

Water pollution, as the remarkable environmental remediation issue, is a today worldwide concern. Cadmium ion (Cd2+) as a hazardous water pollutant is seriously detrimental to human health, food safety, and ecological areas. Hence, we successfully designed a simple detection array for monitoring of ultra-low levels of Cd2+ ion by combining the advantages of aptamer as a high sensitive and selective sensing probe and zeolitic imidazolate framework-8 (ZIF-8) as a superior fluorescence quenching inducer. To have a portable and on-site detection assay, the aptamer biosensing array (aptasensor) was designed by using a paper-supported substrate. The basis of the designed paper-supported aptasensor was the specific complexation of Cd2+ with the aptamer strand, adsorption of fluorescein-labeled complementary (FAM-CP) strand on the ZIF-8 surface, and fluorescence quenching of FAM molecule after the leakage of the injected target solution on the sample zone of the paper substrate to the detection part. A linear relationship was obtained between the Mean Gray Value index, as a criterion for the fluorescence quenching, and the Cd2+ concentration in the range of 0.1–120 pM with a detection limit of 0.076 pM. The aptasensor could detect Cd2+ in the diverse real sample, including tap water, milk, coffee, and human blood serum.

Evaluation of three resin cements in the production of cone beam computed tomography artifacts in teeth with fiberglass posts

The present study analyzed the presence of artifacts in endodontically treated teeth restored with fiberglass posts (FP) cemented with different resin cements by means of cone beam computed tomography (CBCT) in order to evaluate the contrast-to-noise ratio (CNR). A total of 60 mandibular premolars were selected to assemble the phantoms in order to simulate a clinical situation. The teeth were allocated to 6 groups, in which G1, G2 and G3 were endodontically treated teeth restored with FP cemented with Nexus 3, Duo-Link, and Allcem Core resin cements, respectively; G4: endodontically treated teeth restored with FP; G5: teeth treated only endodontically; and G6: healthy teeth. Mean gray scale values were analyzed in the axial images of the cervical, middle and apical thirds of the post length. CNR analysis was conducted on all groups except G5 and G6. There was a statistically significant difference in the mean values of the middle third region regarding the groups analyzed (p=0.026). However, artifacts were observed in all studied groups. The statistical difference observed between the cervical and apical thirds when the groups were evaluated together did not characterize the absence of artifacts between the resin cements, even when only the FP was present. Consequently, the choice of a resin cement might be based on ease of handling, better working time, cost-effectiveness, activation modes, substrate conditions, and clinical aspects. In summary, image quality was found to be compromised by artifacts in the presence of FP through CBCT with or without the resin cements in the root canal.

Validation of a Novel Microfluidic Platform by Imaging Diet Uptake in Zebrafish (Danio rerio) Larvae.

Jesse Orell*, Dakota Parnell*, Chandler Russell*, and James Walters, Ph. D*. *Dept of Applied Science and Mathematics, Bluefield State College, Bluefield, WV, 24701. Validation of a Novel Microfluidic Platform by Imaging Diet Uptake in Zebrafish (Danio rerio) Larvae. &#x0D; A functional microfluidic imaging platform allows the study of several conditions such as the effect of diets on metabolism/digestion, drug interactions, and effects of gene mutations on metabolic processes. Extended durations of in vivo larval zebrafish microscopy are lacking, especially in regard to metabolism. We aim to extend the duration of in vivo larval zebrafish microscopy by using a novel microfluidic imaging platform capable of exchanging fluid (entry and exit flow), supplying oxygen, and supplying diets/drugs. Zebrafish (Danio rerio) serve as good research models for microscopy and disease related research. Zebrafish are optically transparent in larval stages and share 70% of genes with humans and 84% of which shared genes are known to be disease related. We first describe the optimal feed time to compare free feeding larval dietary consumption to larvae fed in the microfluidic platform, we imaged seven days post-fertilization (DPF) larvae fed at 1-, 3-, 5-, 7-, and 9-hour durations (10 larvae/timepoint, 3 replicates) with a Zeiss Discovery V8 microscope. We used a diet of 5% egg yolk spiked with Fluosphere polystyrene beads (580/605)™ to track the amount of diet consumed. We found the 5-hour timepoint was the best one to measure because fluorescent mean gray value quantified by NIH ImageJ had minor variation, and all larvae had fed. Future experiments will determine if seven DPF larvae will consume food equally in the microfluidic imaging platform environment. If seven DPF larvae feed equally in the microfluidic imaging platform it suggests an improved environment for imaging zebrafish larvae.

Nuclear morphometry and chromatin texture changes in hepatocellular carcinoma samples may predict outcomes of\xa0liver transplanted patients

BackgroundNuclear changes are typical in the carcinogenesis of hepatocellular carcinoma (HCC). Morphometry and chromatin texture analysis are quantitative methods for their quantification. In this study, we analyzed nuclear morphometry and chromatin texture parameters in samples of hepatocellular carcinoma from liver transplant patients and their associations with clinicopathologic variables.MethodsSamples of HCC and adjacent tissue from 34 individuals were collected in tissue microarray blocks. Stained slides were microphotographed using an optical microscope and nuclear parameters analyzed in ImageJ (FracLac plug-in). ROC curve analysis was used to find accurate cut-offs for differentiation of neoplastic and non-neoplastic cells. The inter-rater agreement was also evaluated.ResultsNuclear morphometric and textural differences were observed between the samples of HCC and adjacent tissue of liver transplant patients. Lower mean gray value (p = 0.034) and Feret diameter (p = 0.024) were associated with higher Model for End-Stage Liver Disease (MELD) scores. Nuclei with larger area (p = 0.014) and larger Feret diameter (p = 0.035) were associated with lower survival. Lower aspect ratio was associated with HCC recurrence after the transplant (p = 0.048). The cut-off of 1.13 μm (p = < 0.001) for aspect ratio and cut-off of 21.15 μm (p = 0.038) for perimeter were established for the differentiation of neoplastic and non-neoplastic cells. The morphometric analysis was reproducible to area, circularity, Feret diameter, mean gray value and aspect ratio between observers (p = < 0.001).ConclusionsNuclear morphometric differences between the HCC and the adjacent tissue samples were associated with prognostic variables (MELD scores, recurrence and survival) and may predict liver transplant patients’ outcomes.

FV 3 Cytoskeletal analysis in sensory nerve fibre endings show a decrease of neurofilaments in high aggressive spinal Amyotrophic lateral sclerosis

Introduction: Amyotrophic lateral sclerosis (ALS) is a multisystemic, neurodegenerative disease, which is characterized by distal axonopathy and motor neuron loss and thereby leads to muscular weakness and death during 3-5 years after symptom onset due to respiratory failure. Neurofilaments are well-established biomarkers in ALS as they show increased levels in CSF compared to healthy controls as an expression of axonal damage and predict disease aggressiveness (by using the D50 progression model) and survival in ALS [1]. Together with their posttranslational modifications, neurofilaments and microtubules are critical components in cytoskeletal pathology of motor neuron diseases. Also, there are several ALS-related genes known to directly affect cytoskeletal dynamics, like TUBA4A, KIF5A or DCTNI1, which can interfere axon stability and axonal transport. In this study, we investigate the cytoskeleton in sensory nerve fiber endings of ALS patients to get a closer look in axonal pathology in ALS. Material and Methods: We performed skin biopsies of the proximal and distal leg in ALS and healthy controls. Those were immunostained for microtubules (ßIII-tubulin), neurofilaments (phosphorylated/non-phosphorylated neurofilaments – pNfH/npNfH) and actin and the individual fibres were analyzed for mean grey value intensity and axonal caliber in confocal images of the dermis. Additionally, we added electron microscopy (EM) of the biopsies to evaluate accumulation of cytoskeleton components or disorders in organelle transport. By using the D50 progression modell, based on functional loss in ALSFRS-R score, we also included the individual disease course and evaluate disease aggressiveness and disease accumulation for each ALS patients. Results: Our preliminary results show that ALS patients have an increase of mean grey value intensities for neurofilaments, ßIII-tubulin and actin compared to healthy controls. In subgroup analysis of ALS, compared by disease onset and disease aggressiveness, we see a trend for decrease in high aggressive spinal and bulbar ALS vs. low aggressive spinal ALS. Also, EM shows organelle transport disorders like mitochondrial accumulation in sensory nerve fibre endings in some cases of ALS. Conclusion: Analysis of skin biopsies may provide a simple tool to study axonal pathology in ALS and may be useful to predict disease aggressiveness as neurofilaments in sensory nerve fibre endings show a decrease in high aggressive spinal ALS. Further, we want to take a closer look to posttranslational modifications of microtubules, investigate the length dependence (proximal vs. distal), add longitudinal analysis and also correlate the results with clinical data and biomarkers, eg. neurofilaments in serum and CSF.

Automated recognition and analysis of head thrashes behavior in C. elegans

BackgroundLocomotive behaviors are a rapid evaluation indicator reflecting whether the nervous system of worms is damaged, and has been proved to be sensitive to chemical toxicity. In many toxicological studies, C. elegans head thrashes is a key indicator of locomotive behaviors to measure the vitality of worms. In previous studies, the number of head thrashes was manually counted, which is time-consuming and labor-intensive.ResultsThis paper presents an automatic recognition and counting method for head thrashes behavior of worms from experimental videos. First, the image processing algorithm is designed for worm morphology features calculation, mean gray values of head and tail are used to locate the head of worm accurately. Next, the worm skeleton is extracted and divided into equal parts. The angle formulas are used to calculate the bending angle of the head of worm. Finally, the number of head thrashes is counted according to the bending angle of the head in each frame. The robustness of the proposed algorithm is evaluated by comparing the counting results of the manual counting. It is proved that the proposed algorithm can recognize the occurrence of head thrashes of C. elegans of different strains. In addition, the difference of the head thrashes behavior of different worm strains is analyzed, it is proved that the relationship between worm head thrashes behavior and lifespan.ConclusionsA new method is proposed to automatically count the number of head thrashes of worms. This algorithm makes it possible to count the number of head thrashes from the worm videos collected by the automatic tracking system. The proposed algorithm will play an important role in toxicological research and worm vitality research. The code is freely available at https://github.com/hthana/HTC.

A Comparative Evaluation of the Radiopacity of Contemporary Restorative CAD/CAM Blocks Using Digital Radiography Based on the Impact of Material Composition

Purpose The main purpose of this study was to assess the radiopacity of contemporary restorative computer-aided design (CAD)/computer-aided manufacturing (CAM) materials and the impact of material composition as measured by energy-dispersive X-ray spectrophotometry (EDX) on radiopacity. Materials and Methods Ten specimens of six CAD/CAM materials with 1 mm thickness were produced and then digitally radiographed with an aluminum (Al) step-wedge (SW) and 1 mm thick tooth slice. The specimen mean gray values (MGVs) were recorded in pixels and compared to an Al-SW, dentin, and enamel of equal thickness. For the elementary analysis of the composition of the materials, EDX was performed. Results The recorded MGVs ranged between 21.20 ± 4.94 and 238.5 ± 13.61 pixels. Materials were sorted according to the MGVs descendingly, Prettau, Vita Suprinity, Vita Enamic, Shofu, Pekkton, and BioHPP. Prettau and Vita Suprinity had significantly higher MGV than dentin and 1 mm thick Al. In comparison, Vita Enamic had a slightly higher value than dentin and 1 mm thick Al. Although Pekkton and BioHPP had MGV significantly lower than dentin and 1 mm thick Al, Shofu had a significantly lower value than dentin and nonsignificantly lower than 1 mm thick Al (p < 0.05). According to EDX analysis, the examined materials contained several components in varying quantities of radiopacity. Conclusions The radiopacity of only three studied materials exceeded the International Organization for Standardization's minimum standards (ISO).

Comparing Radiopacity of Nanohybrid Composite and Giomers: An In Vitro Study

Aim: The aim of this study was to evaluate and compare the radiopacity of three different composite resins; one nanohybrid and two giomers.&#x0D; Material and Methods:&#x0D; For evaluation of radiopacity of composites, ten specimens of each material [(3 groups) (total 30) (n=10] with thicknesses of 2 mm were prepared and radiographed alongside aluminum step wedge and human enamel and dentin. Occlusal radiograph was taken and mean gray values of the test materials were measured using Image J software. Then a conversion was performed to establish the radiopacity of the test materials, in millimeters of equivalent Aluminum (Al). Data were analyzed using one‑way analysis of variance and Scheffe’s Post Hoc tests (P &lt; 0.05).&#x0D; Results: &#x0D; The radiopacity values varied among the restorative materials (p &lt; 0.05) with the highest for Filtek followed by Beautifil Injectable, Beautifil 2, enamel and dentin.&#x0D; &#x0D; Conclusion: &#x0D; All materials tested had radiopacity values greater than dentin and had sufficient radiopacity to meet International Organization for Standardization 4049 standard.&#x0D; &#x0D; Key Words: Radiopacity, aluminum stepwedge, composites, opacifing-fillers.

Treatment responses for branch retinal vein occlusion predicted by semi-automated fluorescein angiography quantification

BackgroundsBranch retinal vein occlusion (BRVO) is one of the most important causes of visual loss in retinal vascular diseases. The aim of this study is to predict the treatment response of anti-vascular endothelial growth factor (anti-VEGF) therapy in BRVO using semi-automated quantified fluorescein angiography (FA) features.MethodsThis retrospective case-control study enrolled patients with BRVO who are receiving anti-VEGF therapy and have been followed up for > 1 year. Those receiving < 5 anti-VEGF injections in the first year were classified as the responsive group, while those receiving ≥5 injections were the refractory group. The FA images were subjected to semi-automated pre-processing. Fluorescein leakages at the 5-min image were represented by mean gray value over parafoveal and perifoveal regions. FA leakages and central retinal thickness (CRT) on optical coherence tomography (OCT) were used for predicting the treatment response and compared using area under receiver operating characteristic curve (AUC).ResultsEighty-nine patients (56 males, 33 females, mean age 62.5 ± 10.9 years) with BRVO were enrolled. Of the 89 eyes, 47 (53%) were in the responsive group and 42 (47%) were in the refractory group. The refractory group had a significantly higher number of anti-VEGF injections in the first year (5.9 ± 1.6 versus 2.4 ± 1.2, p < 0.001) when compared with that of the responsive group. It had thicker pre-treatment CRT (p = 0.011), post-treatment best CRT (p < 0.001) and CRT at 1-year (p < 0.001). It also had a higher mean gray value over the parafoveal (p < 0.001) and the perifoveal (p < 0.001) regions. The mean gray value over perifoveal (AUC 0.846) and parafovel (AUC 0.818) had significantly larger AUC than that of the pre-treatment OCT (AUC 0.653; p = 0.005 and p = 0.016, respectively) when predicting treatment response.ConclusionThe refractory group had a more severe fluorescein leakage over the parafoveal and the perifoveal regions than the responsive group had. Semi-automated quantified FA leakage can be used as a biomarker for the prediction of anti-VEGF treatment response in macular edema due to BRVO.

Computerized histogram analysis of the canine placenta during normal pregnancy

In this study, the aim was to evaluate digitalized images obtained via B-mode sonography (USG) during different stages of pregnancy and to assess features of the canine placenta, typical for the different gestational periods. For this purpose, ultrasound pictures were digitalized and a computerized histogram analysis performed. Finally, 151 USG images were obtained from 37 healthy, pregnant dogs of different breeds, aged 4.4 ± 1.8 years, between days 17 and 62 of gestation, and 755 Regions of Interest (ROI) within these images were evaluated. Five ROI per picture were situated in the ventral and dorsal uterus/placenta (early stages) or exclusively the placenta (later stages). The data were grouped into GI: gestational day 17–25, GII: gestational day 26–40, GIII: gestational day 41–50 and GIV: gestational day 51–62.The mean grey value (MGV), standard deviation of grayscale value (StdDGV), minimum grey value (MinGV), maximum grey value (MaxGV), Modal/Mode grey value (ModGV), median grey value (MedGV), homogeneity (Angular Second Moment, ASM), contrast (CONT), correlation (COR), regional homogeneity (Inverse Difference Moment, IDM) and the entropy (ENT) parameters in the Region of Interest (ROI) were calculated.In the course of pregnancy, the grey value parameters, CONT and the local homogeneity (IDM) changed characteristically. The MGV increased between days 17 and 40 (p < 0.0001) and decreased towards late gestation (GIV, p < 0.0001). In parallel, the ModGV, MedGV and MaxGV values changed significantly (p < 0.0001). Similarly, CONT value significantly increased between implantation (GI) and later gestational periods, together with the increasing grayscale variation, probably indicating the massive increase in vascularisation during mid-gestation. This is supported by the fact that local homogeneity (IDM) was highest during implantation and decreased towards late pregnancy (p < 0.01). There was no difference between groups in terms of ASM, COR and ENT (p > 0.05). We conclude that some of the parameters evaluated by computational analysis increased or decreased with the progression of pregnancy, and correlated with the gestational period of bitches. Further studies will reveal whether this technique can contribute to early diagnosis of placental alterations.

Comparative radiopacity of pediatric dental restorative materials

Background/Aim: Radiopacity of dental restorative materials is significant to detect secondary caries, overhangs, and voids. This study aimed to evaluate whether radiopacity of dental restorative materials used in pediatric dentistry was sufficient. Material and Methods: Specimens of 2 mm thickness and 4 mm diameter were prepared in the plastic molds. Six composite materials, one compomer material, and one conventional glass ionomer cement were used and three specimens of each material were prepared. Three radiographs were taken from dental restorative materials and aluminum step wedge. Digital images obtained were recorded. Mean gray values of the dental restorative materials and aluminum step wedge were measured on digital radiographs. Results: All composite resins displayed higher radiopacity values than an equal thickness of 2 mm Al. Posterior composite (201.62±1.99 MGV) showed higher radiopacity value than the anterior composite (86.19 ±1.45 MGV). There was no significant difference in radiopacity values of different shades of the same composite. There was no significant difference in radiopacity values between glass ionomer cement and compomer. Glass ionomer cement showed higher radiopacity value (8.11 mm Al) than anterior composite (5.31 mm Al). Conclusions: Radiopacity values of dental materials used in this study were sufficient. Both resin materials and the glass ionomer cement had sufficient radiopacity values. Posterior composite showed the highest radiopacity value. Radiopacity values were not affected by different shades.

STATISTICAL MODELING OF GLANDULARITY FROM MAMMOGRAPHY IMAGES.

This study presents a methodology for estimation of breast glandularity, which is an important factor to assess radiological risk in mammography patients. The investigation took place in an institution located at department of Antioquia-Colombia, where 200 patients participated. The models were obtained using partial least squares regression, where Dance's model was used as reference; parameters of mammography images, equipment and patient were used as predicting variables (kV, mAs, patient's weight, breast area and mean gray value of breast images). Coefficients of correlation equal to 89 and 88 were obtained for training and validation respectively in mediolateral oblique (MLO) and 84 and 89 for craniocaudal (CC). These models were used to estimate the mean glandular dose for all patients and later to obtain the institutional reference levels, 0.87 and 0.96mGy for CC and MLO, respectively, following the recommendations of the ICRP publication No. 135. This study suggests that glandularity could be estimated with few parameters from equipment and patient.

Comparative evaluation of radiographic density of different endodontic material

The purpose of this study was to evaluate and compare the densities of four different brands of root canal sealers using three different intraoral imaging receptors. Four different root canal sealers used were – AH Plus (Dentsply Germany, Resin based), Epiphany (Pentron USA, Resin based), U/P (Sultan Healthcare, Zinc oxide eugenol based) and Apexit (Ivoclar / Vivadent, Calcium hydroxide based). The sealers were mixed according to manufacturer instructions and six specimens of each material were fabricated. All the specimens were imaged using three different intraoral #2 sized imaging receptors-D and E speed film and storage phosphor plates. D and E speed films were digitized and stored in JPEG format. All the images were exported into the Image J software (rsb.info.nih.gov/ij/) and the mean grey values and integrated density of each material was calculated from four random areas of each image and averaged. Mixed model ANOVA was performed. Pair wise comparison of mean grey values between the three imaging receptors and integral densities recorded by the receptors showed high statistical significance for all the four different root canal sealers. Results showed that the four different types of root canal sealers showed different optical densities on all the three receptors. The purpose of this study is to evaluate and compare the optical densities of four different brands of root canal sealers using three different intraoral imaging receptors.

Revisiting dynamic range and image enhancement ability of contemporary digital radiographic systems.

To assess the dynamic range and enhancement ability of radiographs acquired with contemporary digital systems. Five repeated periapical radiographs of human mandibles with an aluminium step-wedge were acquired using two sensor-based and three photostimulable phosphor plate-based systems and an X-ray unit at ten exposure times 0.020, 0.032, 0.063, 0.080, 0.100, 0.200, 0.320, 0.400, 0.500, and 0.630 s. All images had their brightness and contrast enhanced by two experienced oral and maxillofacial radiologists in consensus and were exported as both the original and enhanced file formats. Mean grey values were obtained from the aluminium steps and tabulated with their corresponding thicknesses for each exposure time, digital radiographic system, and file format. Images with saturated steps were excluded and the mean grey values from the remaining images were averaged to assess image brightness and the angular coefficient of the linear trendlines was generated from the relationship between mean grey values and their corresponding aluminium thicknesses to assess image contrast. Brightness and contrast values were compared using two-way ANOVA with post-hoc Tukey (α = 0.05). Photostimulable phosphor plate-based digital radiographic systems had a broader dynamic range. Longer exposure times produced original images with lower brightness and variable contrast (p < 0.05). Subjective enhancement significantly increased or reduced brightness and/or contrast in some systems (p < 0.05). Contemporary digital radiographic systems present different dynamic ranges and exposure-related brightness and contrast. Image enhancement may be a valuable tool at slightly suboptimal exposure times.

Robust Multi-TE ASL-Based Blood-Brain Barrier Integrity Measurements.

Multiple echo-time arterial spin labelling (multi-TE ASL) offers estimation of blood–tissue exchange dynamics by probing the T2 relaxation of the labelled spins. In this study, we provide a recipe for robust assessment of exchange time (Texch) as a proxy measure of blood–brain barrier (BBB) integrity based on a test-retest analysis. This includes a novel scan protocol and an extension of the two-compartment model with an “intra-voxel transit time” (ITT) to address tissue transit effects. With the extended model, we intend to separate the underlying two distinct mechanisms of tissue transit and exchange. The performance of the extended model in comparison with the two-compartment model was evaluated in simulations. Multi-TE ASL sequence with two different bolus durations was used to acquire in vivo data (n = 10). Cerebral blood flow (CBF), arterial transit time (ATT) and Texch were fitted with the two models, and mean grey matter values were compared. Additionally, the extended model also extracted ITT parameter. The test-retest reliability of Texch was assessed for intra-session, inter-session and inter-visit pairs of measurements. Intra-class correlation coefficient (ICC) and within-subject coefficient of variance (CoV) for grey matter were computed to assess the precision of the method. Mean grey matter Texch and ITT values were found to be 227.9 ± 37.9 ms and 310.3 ± 52.9 ms, respectively. Texch estimated by the extended model was 32.6 ± 5.9% lower than the two-compartment model. A significant ICC was observed for all three measures of Texch reliability (P < 0.05). Texch intra-session CoV, inter-session CoV and inter-visit CoV were found to be 6.6%, 7.9%, and 8.4%, respectively. With the described improvements addressing intra-voxel transit effects, multi-TE ASL shows good reproducibility as a non-invasive measure of BBB permeability. These findings offer an encouraging step forward to apply this potential BBB permeability biomarker in clinical research.

Beç Tavuklarında (Numida meleagris) Sayısal Görüntü Analizi ve Matematiksel Formüller Kullanılarak Yumurta Kalite Özelliklerinin Belirlenmesi

A total of 200 Guinea fowl (Numidae meleagris) eggs were obtained from guinea fowl flock at the age of 42 weeks of age, which are breeding at an altitude of 1240 m in the Wild Animals Breeding Station affiliated to Ministry of Forest and Water Affairs in Yozgat/Turkey. Eggs were taken at a resolution of 72 pixels per inch and 5184 × 3456 pixels in size, with the individual egg weights. Average Projection area (16,07 cm2), Perimeter (15,82 cm), Circularity (0,81), Height (5,17 cm), Width (4,04 cm), Mean grey value (82,82), Semi axis (2,02 cm), First long half height (2,96 cm), Second short half height (2,20 cm) values were determined by numerical image analysis. Mean Elongation (1,28), Shape Index (78,27) were calculated over the obtained data. Surface area (55,43 cm2), Height (5,16 cm), Width (3,77 cm), Elongation (1,37), Shape Index (73,01), Volume (40,14 cm3), Surface / Volume ratio (1,38), Shell weight (3,17 g), Shell thickness (0,28 mm), pore numbers (6666,25; 5132,39; 5011,12), pore density (120,32; 92,56; 90,31), Yellow ratio (14,85), Yellow Weight (5,95 g), Albumen Weight (30,75), Albumen ratio (77,21) parameters have been calculated using individual egg weights. Eggs were divided into 3 groups as 90 in terms of gray value, eggs 79 in terms of shape index, and 43 in terms of weight. The effects on the properties were investigated. As a result, it is thought that the data obtained can be used in scientific studies.

Automated characterisation of glaciomarine sediments using X-ray computed laminography

This study investigates the potential of a new high-resolution, non-destructive, X-ray imaging technique for the Quaternary Sciences – computed laminography (CL). Greyscale properties are systematically extracted from digital X-radiographic CL images of cored glaciomarine sediments to analyse and characterise sediments at pixel-scale resolution (<0.1 mm). We show how this can be achieved manually, and also with an easy-to-use, automated statistical tool which we have devised specifically for use in glaciomarine sediments. This Sediment Characteristics tool, in the form of a plugin for the freely available FIJI/ImageJ programme, extracts mean or median X-ray grey values (GV) – a proxy for sediment density; and associated standard deviation (SD) – a proxy for sediment heterogeneity – at sub-mm resolution, across the width of sediment core CL images. We demonstrate how these properties (GV and SD) can be directly used to characterise sediment properties and in particular to quantify the abundance of gravel clasts, or ice-rafted debris, in cored glaciomarine sediments. The tool’s effectiveness is compared with other, more traditional, X-radiographic methods for counting ice-rafted gravel clasts in glaciomarine sediment. We propose that the CL output and Sediment Characteristics tool also have the potential to quantitatively analyse other 3-dimensional structures, such as cyclic lamination (varve) geometry; deformation structures; bioturbation and void space (porosity). Finally, we present the raw code, allowing open-access, transparency and reproducibility in other formats.