Mean Gray Scale Values Research Articles

Correlations between [18F]flutemetamol PET and region‐matched postmortem integrated density measures of cyano‐flutemetamol signal in Aβ plaques

AbstractBackgroundThe binding substrates of [18F]flutemetamol and [11C]PiB PET consist of fibrillar amyloid‐β (Aβ) aggregates in morphologically and structurally distinct diffuse plaques (DP) and cored plaques (CP) which are present at different proportions across brain regions in Alzheimer’s disease (AD). To account for this heterogeneity, an unbiased quantitative measure integrating plaque size and density of amyloid‐β (Aβ) fibrils in plaques could help avoid false positive results, improve imaging‐to‐autopsy correlations, and further advance our understanding of pathological substrates for binding of amyloid PET tracers.MethodSixteen subjects underwent [18F]flutemetamol PET imaging in the pivotal Phase III end‐of‐life study (Study GE067‐007 and GE067‐026) and later came to autopsy (mean imaging‐to‐autopsy interval was 111 ± 87.6 days). [18F]flutemetamol SUVRpons values in four neocortical regions were correlated with region‐matched postmortem measures of cyano‐flutemetamol labeling of all plaques, as well as CP and DP separately, using percent area coverage, mean grayscale intensity of fluorescence, or a combination of the two measures referred to as integrated density.ResultIn the analysis of all cyano‐flutemetamol‐labeled plaques, [18F]flutemetamol SUVRpons values were more closely associated with integrated density measures than percent area coverage and mean grayscale values. Similarly, when CP and DP were analyzed separately, the integrated density values showed the closest association with neocortical region‐matched [18F]flutemetamol SUVRpons values. When area coverage of CP and DP were each expressed as a fraction of total plaque area coverage with or without integrating fluorescence intensity values, [18F]flutemetamol SUVRpons values within each region of interest were associated with the DP, but not the CP, area coverage measure.ConclusionThe association of antemortem [18F]flutemetamol PET and region‐matched postmortem integrated density measurements of cyano‐flutemetamol labeled plaques further supports the hypothesis that amyloid PET signal is influenced both by plaque size and Aβ fibril density within DP and CP. Further elucidating the relative contributions of each plaque type to the retention of amyloid PET radioligands could influence how a positive amyloid PET signal is interpreted in relation to postmortem pathology data.

Correlations between [18F]flutemetamol PET and region‐matched postmortem integrated density measures of cyano‐flutemetamol signal in Aβ plaques

AbstractBackgroundThe binding substrates of [18F]flutemetamol and [11C]PiB PET consist of fibrillar amyloid‐ß (Aß) aggregates in morphologically and structurally distinct diffuse plaques (DP) and cored plaques (CP) which are present at different proportions across brain regions in Alzheimer’s disease (AD). To account for this heterogeneity, an unbiased quantitative measure integrating plaque size and density of amyloid‐ß (Aß) fibrils in plaques could help avoid false positive results, improve imaging‐to‐autopsy correlations, and further advance our understanding of pathological substrates for binding of amyloid PET tracers.MethodSixteen subjects underwent [18F]flutemetamol PET imaging in the pivotal Phase III end‐of‐life study (Study GE067‐007 and GE067‐026) and later came to autopsy (mean imaging‐to‐autopsy interval was 111 ± 87.6 days). [18F]flutemetamol SUVRpons values in four neocortical regions were correlated with region‐matched postmortem measures of cyano‐flutemetamol labeling of all plaques, as well as CP and DP separately, using percent area coverage, mean grayscale intensity of fluorescence, or a combination of the two measures referred to as integrated density.ResultIn the analysis of all cyano‐flutemetamol‐labeled plaques, [18F]flutemetamol SUVRpons values were more closely associated with integrated density measures than percent area coverage and mean grayscale values. Similarly, when CP and DP were analyzed separately, the integrated density values showed the closest association with neocortical region‐matched [18F]flutemetamol SUVRpons values. When area coverage of CP and DP were each expressed as a fraction of total plaque area coverage with or without integrating fluorescence intensity values, [18F]flutemetamol SUVRpons values within each region of interest were associated with the DP, but not the CP, area coverage measure.ConclusionThe association of antemortem [18F]flutemetamol PET and region‐matched postmortem integrated density measurements of cyano‐flutemetamol labeled plaques further supports the hypothesis that amyloid PET signal is influenced both by plaque size and Aß fibril density within DP and CP. Further elucidating the relative contributions of each plaque type to the retention of amyloid PET radioligands could influence how a positive amyloid PET signal is interpreted in relation to postmortem pathology data.

A new segment method for pulmonary artery and vein.

Accurate differentiation between pulmonary arteries and veins (A/V) holds pivotal importance in the realm of diagnosing and treating pulmonary ailments. This study presents a new approach that leverages grayscale differences between A/V. Distinctions are measured using median and mean grayscale values within the vessel area. Initially, adherent regions are removed based on vessel structure. The trunk regions are segmented using gray level information near the heart region of the lung boundary. Incorrectly segmented vessels are corrected based on connectivity. For distal lung vessels, a similar distance field is established using a graph-cut method. Experimental results show the algorithm's superior segmentation accuracy, achieving 97.26% compared to the CNN-based average accuracy of 91.67%. Error branches are more concentrated, aiding subsequent manual and automatic correction. This demonstrates the algorithm's effective segmentation of pulmonary A/V.

Evaluation of efficacy of simvastatin in bone regeneration following local application in third molar extraction socket: A randomized control trial.

The aim of this study is to study the efficacy of simvastatin in bone regeneration following the local application in third molar extraction sockets. This is a randomized controlled trial done on 50 patients involving 100 third molar teeth extraction sockets. The patients were randomly divided based on the placement of simvastatin. Extraction sockets which were treated with simvastatin were considered study sockets and without simvastatin were considered control sockets. The study socket was assigned for the placement of simvastatin (10 mg) powder along with gelfoam as carrier moistened with normal saline solution and control socket was assigned for the placement of gelfoam moistened with saline. Intraoral periapical radiographs were taken on the 1st, 4th, 8th, and 12th weeks, and mean gray scale values indicating bone density were evaluated for both the groups. Cone-beam computed tomography (CBCT) was taken by the end of the 12th week to further evaluate the osseous regeneration. Patients were compared and evaluated for bone density, pain, and swelling. Pain and swelling were evaluated on postoperative days 1 and 7. The mean gray-level histogram values (bone density) were statistically highly significant in the study group compared to the control group in the 1st, 4th, 8th, and 12th weeks, and CBCT also showed statistically significant difference between the control and study group by the end of the 12th week. The present data suggest that the local application of simvastatin promotes and enhances bone formation in the extraction sockets, which provides a very cost-effective way for faster bone regeneration.

An Echogenic Clot Method for Thrombolysis Monitoring in Thrombotic Stroke Models.

To demonstrate thrombolytic efficacy of a tissue plasminogen activator (tPA)-loaded echogenic liposome (TELIP) formulation in a rabbit thrombotic stroke model (the most relevant animal model for evaluation of directed thrombolytic therapy for ischemic stroke), we sought to develop a means of monitoring thrombus dissolution quantitatively by ultrasound imaging methods. We hypothesized that a gas-free ultrasound contrast agent can be incorporated into blood clots at a concentration that does not affect the tPA-mediated clot dissolution rate, while enabling quantitative assessment of the clot dissolution rate. Clots were formed from a mixture of whole rabbit blood, 1 M calcium chloride, human thrombin and varying amounts of microcrystalline cellulose. Washed clots in tubes were weighed at 30, 60 and 90 minutes after addition of recombinant tPA (rtPA) in porcine plasma (100 μg/ml). Clot echogenicity at each time point was assessed using a Philips HDI 5000 ultrasound system using an L12-5 linear array probe. Recorded Images underwent videodensitometric analysis that converted image reflectivity to mean gray scale values (MGSV). We found that 1.12 mg/ml of microcrystalline cellulose in rabbit blood clots (0.2 ml) provided optimal echogenicity without affecting clot dissolution rates (0.3-0.6 mg/min.) caused by rtPA. The clot dissolution rate measured by videodensitometric analysis of the echogenic clots agreed well with that determined by mass loss measurements (0.28% 0-time value/minute). This method will be important for demonstrating in vivo efficacy with potentially decreased hemorrhagic effects provided by directed tPA vehicles relative to systemic administration of the free thrombolytic.

Immediate and Long-Term Radiopacity and Surface Morphology of Hydraulic Calcium Silicate-Based Materials.

The present study aimed to evaluate and compare the radiopacity and surface morphology of AH Plus Bioceramic Sealer (AHPB), Bio-C Sealer (BIOC), Biodentine (BD), BioRoot RCS (BR), Grey-MTAFlow (GMF), White-MTAFlow (WMF), TotalFill BC Sealer (TF), and TotalFill BC Sealer HiFlow (TFHF) at different time moments—30 min, 24 h, and 28 days. Ten specimens of each material were prepared according to the ISO-6876:2012 standard and radiographed next to an aluminum step wedge using a digital sensor. The specimens were stored in a gelatinized Hank’s balanced salt solution at 37 °C between assessments. The mean grayscale values of each specimen were converted into equivalent aluminum thickness by a linear regression model. Characterization of the surface morphology was performed by using a scanning electron microscope at ×4.0k and ×10.0k magnifications. The radiographic analysis revealed that all the tested materials exceeded the ISO-specified limit of 3 mm Al, with the highest radiopacity presented by AHPB and the lowest by BD. None of the tested materials demonstrated considerable variances between the 30 min and the 24 h radiopacity level (p < 0.05), and statistically significant long-term radiopacity changes were exhibited by BR, TFHF, and TF (p > 0.05). All the specimens demonstrated a common feature of limited precipitate formation, with numerous unreacted particles still presented on the surface after 24 h, whereas the particle rearrangement and the deposition of precipitates were clearly observed after 28 days.

Feasibility of anterior temporalis muscle ultrasound for assessing muscle wasting in ICU: a prospective cohort study.

Skeletal muscle ultrasound is a valuable tool for assessing muscle wasting in ICU. Previous studies on skeletal muscle ultrasound in ICU have been performed on lower limb muscles. The current study is formulated to assess the feasibility and reliability of anterior temporalis (AT) muscle ultrasound for measuringmuscle wasting in ICU. In this prospective cohort study in 48 critically ill patients with sepsis, muscle layer thicknesses (MLTs) and mean grayscale (GS) values of anterior temporalis muscles and quadriceps femoris (Q) were measured at baseline and serially till 7days. Correlation was made between baseline and change in MLT and GS values of AT and Q muscle and these parameters were compared between ICU survivors and non survivors. Baseline anterior temporalis MLTs or their longitudinal changes over 7days did not correlate significantly with the corresponding parameters of quadriceps femoris muscles. The baseline GS values of two muscle groups correlated weakly at baseline, but the change in GS over 7days showed no correlation. The baseline MLTs of both muscle groups and their longitudinal change over 7days did not correlate with ICU length of stay. The change in MLT of AT over 7days was significantly greater in ICU non-survivors compared to survivors. Measurement of ultrasonographic muscle layer thickness and grayscale parameters of anterior temporalis muscle did not show good correlation with that of quadriceps muscle.

Evaluation of contrast-enhanced ultrasonography with Sonazoid® in visualization of local anesthetic distribution in rectus sheath block: a prospective, clinical study.

Clear visualization of ultrasound (US) images is crucial for successful US-guided nerve block. However, accurate determination of local anesthetic (LA) distribution from US images remains difficult. Sonazoid®, which comprises perflubutane microbubbles, is used to diagnose hepatic and breast tumors. This study aimed to investigate the visibility of Sonazoid® in perioperative US-guided nerve block. We performed rectus sheath block (RSB) in patients scheduled for laparoscopic abdominal surgery (n = 10). 10mL of a mixture containing equal amounts of 0.75% ropivacaine and iohexol with the addition of Sonazoid® diluted 100-fold was administered. We investigated the correlation and agreement between Sonazoid® and iohexol distributions. The brightness of the solution and tissues was calculated: a grayscale value between 0 (dark) and 255 (bright) was measured in all pixels of the region of interest. Adverse events were also investigated. Sonazoid® was clearly visualized and distinguished from the surrounding tissues both during and after RSB. The spread of Sonazoid® and iohexol was significantly correlated (spearman's ρ = 0.53, p = 0.0004). Bland-Altman analyses revealed significant mean difference between two methods (15.6mm; 95% confidence interval [CI]: 10.6, 20.6; standard deviation (SD) 15.65; p < 0.0001). Limits of agreement were -14.94 to 46.24mm. Sonazoid® significantly increased the mean grayscale values at the posterior rectus sheath (93.7 vs. 201.9, p < 0.0001). There were no complications. Sonazoid diluted 100-fold® was clearly visualized real-time, and the enhancement was sustained and measurable after RSB. Sonazoid® could potentially be used for the contrast agent of US-guided nerve block.

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.

Collagen deposition correlates with loss of E-cadherin and increased p63 expression in dysplastic conditions of oral submucous fibrosis

This paper focuses on the status of epithelial markers, E-cadherin, and p63 in the backdrop of an abnormal amount of collagen in the sub-mucosa of dysplastic and non-dysplastic grades of OSF. Histologically confirmed OSF and normal oral mucosa samples were procured. Samples were stained by Van Gieson's stain (VG) and immunohistochemistry. The captured images were analyzed by ImageJ software to quantify their grayscale intensities. There was a gradual increase in the intensity of VG stain from normal to non-dysplastic and dysplastic OSF and the differences in their mean grayscale values were found to be significant (p < 0.00001). The intensity of E-cadherin was found to be the highest in non-dysplastic conditions and lowest in dysplastic conditions. The intensity difference of E-cadherin between normal and non-dysplastic OSF was found to be significant (p < 0.00001). The grayscale scale intensity values for p63 in whole epithelium depicted significant differences between normal and diseased conditions but for its intensity, in basal cells, significant differences were found between non-dysplastic and other classes of tissues. There was a positive correlation observed between VG and p63 staining intensity. The diseased oral epithelium demonstrated greater deposition of sub-epithelial collagen fibers along with subsequent loss of E-cadherin and an increased p63 expression.

Does the quality of residual alveolar bone apical to a periodontal lesion beneath the maxillary sinus play a vital role in preventing the extension of periodontal disease to maxillary sinus? A CBCT-assisted retrospective study.

The mucous membrane of the maxillary sinus is sensitivis susceptible to infection or inflammation adjacent to it, which may contribute to mucous membrane thickening (MMT). Residual alveolar bone quality (RABQ) is considered a quality of the remaining bone apical to periodontal defect adjoining to the floor of the maxillary sinus. The current study aimed to analyze the minimum RABQ to prevent the extension of periodontal pathology from reaching maxillary sinus using cone-beam computed tomography (CBCT). In this retrospective observational study, 240 sinus exposure CBCT records of 146 patients were evaluated. Patients with at least one sinus exposure were included. RABQ and MMT were calculated using CBCT inbuilt tools. RABQ was divided into four groups based on gray scale values (GSV). Statistical analysis was performed using one way ANOVA and independent sample t-tests. Correlation was completed applying Pearson's correlation coefficient. A significant difference (p< 0.05) was observed between the MMT values of the four RABQ groups. Inverse correlation was observed between mean MMT and GSV values. Mean MMT was higher than pathological MMT range (> 2mm), with significant differences in groups A and B, where mean GSV values are less than 500. Mean GSV greater than 500 in groups C and D show non-pathological MMT. Prevalence of MMT is 91.4% if GSV is < 500 and 7.5% if GSV is > 500. Our study suggests that MMT is present if RABQ has GSV values < 500. Maxillary sinusitis and its etiology from periodontal pathology can be excluded based on RABQ adjoining periodontal lesion. Early detection and prompt treatment along with appropriate regenerative protocols can be performed to increase the RABQ. Further microbiological investigation is required to support the present results.

Effect of cabergoline alginate nanocomposite on the transgenic Drosophila melanogaster model of Parkinson’s disease

Parkinson’s disease (PD) is a common neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra of the midbrain. Dopamine agonists help the patients with PD by reversing the dopamine depletion and related motor deficits. In the present work, cabergoline, a potent ergot dopamine agonist, was given in the form of cabergoline alginate nanocomposite (CANC) to the PD model flies to study its effects on climbing ability, activity pattern, life span, lipid peroxidation, glutathione (GSH) content, glutathione-S-transferase (GST) activity, dopamine content, protein carbonyl content, mean gray-scale values, and caspase-3 and caspase-9 activities. Cabergoline alginate nanocomposite was synthesized by adding the cabergoline solution in the warm aqueous solution of sodium alginate; The synthesized CANC was characterized using fourier transform (FTIR) infrared spectroscopy, transmission electron microscopy (TEM), and UV–Visible spectroscopic techniques. The synthesized CANC having the final doses of 1, 2, and 3 μM was supplemented with diet and the flies were allowed to feed on it for 24 days. Cabergoline alginate nanocomposite significantly increases climbing ability, reduces lipid peroxidation, GST activity, protein carbonyl content, caspase 3/9 activity, mean gray-scale values, and increases the GSH as well as dopamine content in a dose-dependent manner. The results of this study suggest that CANC is potent in delaying and reducing the symptoms of PD.

Abstract 334: An Echogenic Clot Method for Thrombolysis Monitoring of Directed Lytics in Thrombotic Stroke

Background: We have previously demonstrated thrombolytic efficacy of tissue plasminogen activator (tPA)-loaded echogenic liposomes (TELIP), a directed therapeutic construct that features exposed tPA fibrin-binding sites, in a rabbit abdominal aorta thrombosis model. The most relevant animal model for evaluation of directed thrombolytic therapy for ischemic stroke is the rabbit thrombotic stroke model previously used to validate recombinant tPA (rtPA; Alteplase). The ability to precisely monitor tPA-mediated thrombus dissolution in vivo is important for quantitative assessment of directed TELIP efficacy. Hypothesis: A gas-free ultrasound contrast agent can be incorporated into blood clots at a concentration that does not affect the tPA-mediated clot dissolution rate, while enabling quantitative assessment of the clot dissolution rate. Methods: In 1.5-ml Eppendorf tubes, 0.2-ml clots were formed from a mixture of whole rabbit blood, 1 M calcium chloride, human thrombin and various amounts of microcrystalline cellulose. At 0-time, 50 μg rtPA in 0.5 ml porcine plasma was added to each tube. Washed clots in tubes were weighed with an analytical balance at 30, 60 and 90 minutes. Clot echogenicity at each time point was assessed with a Philips HDI 5000 ultrasound system using an L12-5 linear array probe positioned laterally to tubes placed in an anechoic chamber. Recorded Images were subjected to videodensitometric analysis that converted image reflectivity to mean gray scale values (MGSV). Results: We found that 1.12 mg/ml of microcrystalline cellulose in rabbit blood clots (0.2 ml) provided optimal echogenicity without affecting the clot dissolution rates (0.3-0.6 mg/min.) caused by 100 μg/ml of rtPA. The clot dissolution rate measured by videodensitometric analysis of serial sonograms of the echogenic clots agreed well with that determined by mass loss measurements (0.28% 0-time value/minute). Conclusions: We have developed a method for monitoring rtPA-mediated clot mass loss by ultrasound imaging techniques and validated it in vitro. This method will be important for demonstrating the enhanced efficacy and decreased hemorrhagic effects provided by directed tPA vehicles relative to systemic administration of the free thrombolytic.

Ultrasound estimates of muscle quality in older adults: reliability and comparison of Photoshop and ImageJ for the grayscale analysis of muscle echogenicity.

Background. Quantitative diagnostic ultrasound imaging has been proposed as a method of estimating muscle quality using measures of echogenicity. The Rectangular Marquee Tool (RMT) and the Free Hand Tool (FHT) are two types of editing features used in Photoshop and ImageJ for determining a region of interest (ROI) within an ultrasound image. The primary objective of this study is to determine the intrarater and interrater reliability of Photoshop and ImageJ for the estimate of muscle tissue echogenicity in older adults via grayscale histogram analysis. The secondary objective is to compare the mean grayscale values obtained using both the RMT and FHT methods across both image analysis platforms.Methods. This cross-sectional observational study features 18 community-dwelling men (age = 61.5 ± 2.32 years). Longitudinal views of the rectus femoris were captured using B-mode ultrasound. The ROI for each scan was selected by 2 examiners using the RMT and FHT methods from each software program. Their reliability is assessed using intraclass correlation coefficients (ICCs) and the standard error of the measurement (SEM). Measurement agreement for these values is depicted using Bland-Altman plots. A paired t-test is used to determine mean differences in echogenicity expressed as grayscale values using the RMT and FHT methods to select the post-image acquisition ROI. The degree of association among ROI selection methods and image analysis platforms is analyzed using the coefficient of determination (R2).Results. The raters demonstrated excellent intrarater and interrater reliability using the RMT and FHT methods across both platforms (lower bound 95% CI ICC = .97–.99, p < .001). Mean differences between the echogenicity estimates obtained with the RMT and FHT methods was .87 grayscale levels (95% CI [.54–1.21], p < .0001) using data obtained with both programs. The SEM for Photoshop was .97 and 1.05 grayscale levels when using the RMT and FHT ROI selection methods, respectively. Comparatively, the SEM values were .72 and .81 grayscale levels, respectively, when using the RMT and FHT ROI selection methods in ImageJ. Uniform coefficients of determination (R2 = .96–.99, p < .001) indicate strong positive associations among the grayscale histogram analysis measurement conditions independent of the ROI selection methods and imaging platform.Conclusion. Our method for evaluating muscle echogenicity demonstrated a high degree of intrarater and interrater reliability using both the RMT and FHT methods across 2 common image analysis platforms. The minimal measurement error exhibited by the examiners demonstrates that the ROI selection methods used with Photoshop and ImageJ are suitable for the post-acquisition image analysis of tissue echogenicity in older adults.

Analysis by means of cone-beam computed tomography, bone density and X-ray beam attenuation of rabbit mandibles subjected to low-level laser therapy during distraction osteogenesis

&lt;p&gt;&lt;strong&gt;&lt;em&gt;Objectives: &lt;/em&gt;&lt;/strong&gt;&lt;em&gt;To assess by means of cone-beam computed tomography (CBCT) the relative bone density of newly formed bone in rabbit mandibles treated with low-level laser therapy (LLLT) during distraction osteogenesis (DO). &lt;/em&gt;&lt;strong&gt;&lt;em&gt;Methods: &lt;/em&gt;&lt;/strong&gt;&lt;em&gt;Seven rabbits underwent surgical osteotomy and immediate installation of a distractor on the mandible (right side). DO was performed for 10 days, and LLLT (aluminum-gallium-arsenide [AlGaAs] infrared laser, λ 830 nm, 40 mW) was applied during distractor activation (days 4-10). Three rabbits were euthanized at the end of the activation period (day 10, group A), and four at the end of the maturation period (day 20, group B). Quality and quantity of newly formed bone in the distracted area were measured on grayscale images using adjacente untreated areas as controls. Two CBCT images were acquired for each animal (before and after removal of soft tissue) to evaluate the influence of the soft tissue on X-ray beam attenuation. &lt;/em&gt;&lt;strong&gt;&lt;em&gt;Results: &lt;/em&gt;&lt;/strong&gt;&lt;em&gt;Mean grayscale values in the distracted area were higher in group B rabbits (140.47 vs. 102.55 in group A), indicating greater bone maturation in a short period. Absence of soft tissues during CBCT scanning was associated with higher grayscale values, indicative of less X-ray beam attenuation. &lt;/em&gt;&lt;strong&gt;&lt;em&gt;Conclusions: &lt;/em&gt;&lt;/strong&gt;&lt;em&gt;It is possible to measure differences in bone density in areas subjected to DO on CBCT scans, providing an objective assessment useful for monitoring bone quality during the repair process.&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt; &lt;/em&gt;&lt;/p&gt;

Skin substitute-assisted repair shows reduced dermal fibrosis in acute human wounds validated simultaneously by histology and optical coherence tomography.

Skin substitutes are heterogeneous biomaterials designed to accelerate wound healing through provision of replacement extracellular matrix. Despite growing evidence for their use in chronic wounds, the role of skin substitutes in acute wound management and their influence on fibrogenesis remains unclear. Skin substitute characteristics including biocompatibility, porosity, and elasticity strongly influence cellular behavior during wound healing. Thus, we hypothesize that structural and biomechanical variation between biomaterials may induce differential scar formation after cutaneous injury. The following human prospective cohort study was designed to investigate this premise. Four 5-mm full thickness punch biopsies were harvested from 50 volunteers. In all cases, site 1 healed by secondary intention, site 2 was treated with collagen-GAG scaffold (CG), and decellularised dermis (DCD) was applied to site 3 while tissue extracted from site 4 was replaced (autograft). Healing tissue was assessed weekly with optical coherence tomography (OCT), before being excised on days 7, 14, 21, or 28 depending on study group allocation for later histological and immunohistochemical evaluation. Extracted RNA was used in microarray analysis and polymerase chain reaction of highlighted genes. Autograft treatment resulted in minimal fibrosis confirmed immunohistochemically and with OCT through significantly lower collagen I levels (p = 0.047 and 0.03) and reduced mean grayscale values (p = 0.038 and 0.015), respectively. DCD developed intermediate scar formation with partial rete ridge reformation and reduced fasiculonodular fibrosis. It was uniquely associated with late up-regulation of matrix metalloproteinases 1 and 3, oncostatin M, and interleukin-10 (p = 0.007, 0.04, 0.019, 0.019). Regenerated dermis was significantly thicker in DCD and autografts 28 days post-injury compared with control and CG samples (p = 0.003 and < 0.0001). In conclusion, variable fibrotic outcomes were observed in skin substitute-treated wounds with reduced scarring in autograft and DCD samples compared with controls. OCT enabled concurrent assessment of wound morphology and quantification of dermal fibrosis.

The Effect of Milk or its Combination with Tea and 0.2% NaF on Dental Enamel Demineralization Analyzed by Micro Computed Tomography

Fluoride and calcium play an important role in the prevention of dental caries, promoting the inhibition of demineralization and the increase of remineralization. Objective: To investigate the effects of milk with/without the combination of tea and 0.2% NaF on enamel demineralization using micro-computed tomography (micro- CT). Methods: The coronal parts of 40 extracted sound premolars were prepared as tooth blocks. An unvarnished occlusal surface window was created for each tooth by covering the occlusal surface with a 3x5 mm2 sticker and painting all other surfaces with an acid-resistant varnish. These blocks were randomly allocated into four groups that were immersed in remineralizing solutions for 26 minutes: Group A, milk; Group B, milk and tea; Group C, milk and 0.2% NaF; and Group D, deionized water (control). Results: After 3 days of immersion in a buffered demineralization solution at pH 4.4, micro-CT scans were taken. The mean grayscale values and the standard deviations are: 98.1 ± 24.0; 90.8 ± 9.1; 92.6 ± 21.4; 81.1 ± 20.3, respectively. The mean grayscale values were significantly different among the four groups (p<0.05), except between groups A and B and between groups A and C. Conclusion: Topical application with milk alone showed a higher protective effect against demineralization compared to the synergic application of milk and tea and milk and 0.2% NaF.

Nitric oxide improves molecular imaging of inflammatory atheroma using targeted echogenic immunoliposomes

ObjectiveThis study aimed to demonstrate whether pretreatment with nitric oxide (NO) loaded into echogenic immunoliposomes (ELIP) plus ultrasound, applied before injection of molecularly targeted ELIP can promote penetration of the targeted contrast agent and improve visualization of atheroma components. MethodsELIP were prepared using the pressurization-freeze method. Atherosclerosis was induced in Yucatan miniswine by balloon denudation and a hyperlipidemic diet. The animals were randomized to receive anti-intercellular adhesion molecule-1 (ICAM-1) ELIP or immunoglobulin (IgG)-ELIP, and were subdivided to receive pretreatment with standard ELIP plus ultrasound, NO-loaded ELIP, or NO-loaded ELIP plus ultrasound. Intravascular ultrasound (IVUS) data were collected before and after treatment. ResultsPretreatment with standard ELIP plus ultrasound or NO-loaded ELIP without ultrasound resulted in 9.2 ± 0.7% and 9.2 ± 0.8% increase in mean gray scale values, respectively, compared to baseline (p < 0.001 vs. control). Pretreatment with NO-loaded ELIP plus ultrasound activation resulted in a further increase in highlighting with a change in mean gray scale value to 14.7 ± 1.0% compared to baseline (p < 0.001 vs. control). These differences were best appreciated when acoustic backscatter data values (RF signal) were used [22.7 ± 2.0% and 22.4 ± 2.2% increase in RF signals for pretreatment with standard ELIP plus ultrasound and NO-loaded ELIP without ultrasound respectively (p < 0.001 vs. control), and 40.0 ± 2.9% increase in RF signal for pretreatment with NO-loaded ELIP plus ultrasound (p < 0.001 vs. control)]. ConclusionNO-loaded ELIP plus ultrasound activation can facilitate anti-ICAM-1 conjugated ELIP delivery to inflammatory components in the arterial wall. This NO pretreatment strategy has potential to improve targeted molecular imaging of atheroma for eventual true tailored and personalized management of cardiovascular diseases.

Pulse duration dependence of cavitation emissions and loss of echogenicity from ultrasound contrast agents insonified by Doppler pulses

Careful determination of stable and inertial cavitation thresholds of UCAs exposed to pulsed ultrasound is required for their safe use in diagnostic and therapeutic applications. Echogenic liposomes and Definity® were diluted in porcine plasma and pumped through a physiological flow phantom. UCAs were insonified with pulsed Doppler ultrasound at three pulse durations (3.33 µs, 5.83 µs and 8.33 µs) over a range of peak rarefactional pressure amplitudes (0.06-1.9 MPa). A 10-MHz focused passive cavitation detector (PCD) was used to record cavitation emissions. PCD signals and B-mode images of UCAs and degassed water were acquired during insonation. Thresholds of stable and inertial cavitation, and loss of echogenicity were determined by piecewise linear fits of the cavitation powers and mean gray scale values, respectively. The stable cavitation thresholds were found to be lower than the inertial cavitation thresholds at each pulse duration setting. The thresholds of loss of echogenicity and stable and inertial cavitation were found to be dependent on pulse duration. The relationship between loss of echogenicity and cavitation emissions will be discussed in the context of using onscreen echogenicity to indirectly monitor cavitation during ultrasound-mediated therapy with UCAs. [Supported by NIH R01 HL059586.]

SU‐D‐301‐05: Angular Dependency of the Slice Sensitivity Profile in Tomographic Breast Imaging

Purpose: To study the effect of angular acquisition on the slice sensitivity profile (SSP) in tomographic breast imaging, for both breast CT and tomosynthesis. Methods: Brass disks (0.025 mm thick) ranging in diameter from 2.5–20 mm were placed within mammography phantoms of varying thicknesses (3–6 cm). The disks were imaged using a prototype digital tomosynthesis system (Selenia Dimensions, Hologic Corporation, Bedford, Ma). The tomosynthesis system acquires images over an angular acquisition range of 15‐degrees. The same brass disks were used to measure the SSP in breast CT, using a 14cm‐diameter cylindrical polyethylene phantom. The bCT angular range spanned from 15 to 360‐degrees. A subset of the projection images were reconstructed with a filtered back projection algorithm to simulate limited‐angle acquisition. The SSP was determined by measuring the mean gray‐scale (GS) in the tomographic images along the z axis of the scan corresponding to the disk position. Normalized profiles of the background‐corrected mean GS values were generated as a function of the distance away from the detector. The full‐width at half maximum (FWHM) GS intensity was determined. Results: As the angular acquisition range increases, the SSP narrows and results in a smaller FWHM value. The FWHM values of the SSP for the smallest disk at (2.5 mm‐diameter) were 8.6 mm, 4.2 mm, and 0.8 mm for 15, 40, and 180 degrees, respectively. Conclusions: Limited angle tomography results in a broadening of the SSP, inversely proportional to the angular range of acquisition. The SSP approaches a minimum as the angular coverage exceeds 180 degrees.One author receives funding from Hologic (Bedford, Mass).