Image Optical Density Research Articles

Psychostimulants prescribed to children for ADHD following distal radius fractures significantly reduce bone density as a function of duration.

Methylphenidate and mixed amphetamine salts (MAS) are psychostimulant medications widely prescribed for various psychiatric disorders. Although these medications are known to adversely impact bone mineral content and density, as well as biomechanical integrity during skeletal development in rats, their effect on bone density in children remains largely unknown. The primary aim of this work was to investigate the effects of methylphenidate and MAS on bone density following distal radius fractures in pediatric populations, and secondarily assess any impact on healing. The retrospective case-control study was designed to assess fracture healing in patients treated with stimulant drugs and matched controls. For the primary outcome, X-rays ( n = 188) were evaluated using an optical density image analysis technique to compare bone density throughout the bone healing process. Results showed that methylphenidate and MAS significantly reduced bone healing by approximately 20% following distal radius fractures in these children. The data also suggested that duration of psychostimulant use played a role in bone healing; the longer the treatment (1-5 years), the lower the bone density was observed (by approximately 52%) as compared to controls (no medication). However, subjects taking these drugs for longer than 5 years did not show a significant difference. Our results suggested that children taking psychostimulants for up to 5 years had slower bone healing following distal radius fractures. Orthopedic surgeons planning elective surgeries should be cognizant of this as a potential issue in recovery after any elective bone procedures and preoperatively optimize bone health as well as counsel patients and their families.

Determination Image Quality on Thorax COVID-19 and Tuberculosis Using Optical Density Image Analysis

Covid-19 is a type of pneumonia disease currently affecting people around the world. Covid-19 and tuberculosis are lung diseases that are dangerous and spread quickly to other humans. Chest radiography is one of the main modalities in the management of suspected COVID-19 and tuberculosis patients as it provides radiological information on lung infections that can be used as diagnostic guidelines and patient care. This study aims to determine the differences in optical density and contrast in Covid-19 and pneumonia tuberculosis cases in order to find the specific characteristics of Covid-19 and tuberculosis. This research processed secondary data from Covid-19 and tuberculosis positive patients using image-J software that can be easily obtained and operated by anyone. After processing, the density and contrast were analyzed, particularly for the lungs. Based on image processing results, the average density for Cnovid-19 radiographs is 1,066, while for Tuberculosis radiograph is 1,519. The average contrast values for Covid-19 and tuberculosis radiographs are 0.37 and 1.03. Thus, it can be concluded that the contrast of the Covid-19 radiograph is lower than the tuberculosis radiograph. The difference in optical density on the tuberculosis and Covid-19 cases is 0.5 as the opacity on the chest radiographs of Covid-19 patients is evenly distributed over the entire lung surface.

Clinical and prognostic effect of MYC protein score in patients with diffuse large B-cell lymphoma in relation to blood group secretor status

Background Lymphoma is the most common blood cancer. Diffuse large B-cell lymphoma (DLBCL) is the most common form of NHL. In Egypt, It represents about 49% of NHL presenting to the National Cancer Institute (NCI), Cairo University. It is an aggressive lymphoma where multiple clinical and laboratory prognostic factors affect its clinical course. Aim The aim of the present study was to determine MYC protein score immunohistochemically and by using image optical density (IOD) in relation to secretor status in patients with DLBCL in order to extrapolate their clinical and prognostic impact. Method Thirty DLBCL patients were enrolled in this study during the period from Oct.1st, 2014 to Oct.1st, 2016 and 15 matched normal subjects as control. The follow up period for the patients was 24 months. A full medical history was taken together with laboratory analyses. Results According to our findings, a high significant relation was found between c-Myc score and IPI (p = 0.009). The mean IOD for Myc expression was statistically and significantly higher in patients with high IPI ((p = 0.001) at a cut off value of 50%) splenomegaly was higher among male patients, lymphocyte/monocyte ratio (LMR) was significantly lower in patients than in the control group and was associated with positive MYC protein expression with high scores (≥50%). Our study also confirmed that secretor status (B +ve) Lewis blood group phenotype carried a better prognosis, a higher overall survival associated and a lower MYC protein score. MYC protein in our patients was significantally correlation to β2M (r= 0.791), LDH (r= 0.697), IPI (r= 0.562) and IOD (r= 0.996). There was a significant negative correlation to Absolute Lymphocytic Count (ALC) (r= - 0.590) and LMR (r= - 0.694). Age, hemoglobin, TLC and platelet count did not show any significantt correlation to MYC protein. Conclusion Expression Determination of MYC scoring and secretor state are highly recommended at the initial evaluation of DLBCL patients.

Вплив процесу ламінування на оптичну щільність зображення, надрукованого цифровим друком на картоні

Вплив процесу ламінування на оптичну щільність зображення, надрукованого цифровим друком на картоні

Development and accuracy evaluation of a degree of occlusion visualization system for roller pumps used in cardiopulmonary bypass.

In roller pumps used for cardiopulmonary bypass (CPB), the degree of blockage within the tube resulting from compression of the tube by the rollers, or the degree of occlusion, is closely related to hemolysis, with both tight occlusive and non-occlusive degrees promoting hemolysis. There are as yet no international standards regarding methods of adjusting occlusiveness, and the amount of mechanical stress exerted upon blood remains unknown. To prevent hemolysis during CPB using roller pumps, there is a need to clarify and quantitatively assess the mechanical stress of the occlusiveness of the roller pump. In this study, we have developed a degree of occlusion quantification system which constructs the flow channel shape within an occluded tube from red optical density images, and we have verified the validity of this system. Utilizing a linear actuator, an acrylic roller and raceway, a solution colored with simulated blood powder, and a 3/8-inch vinyl chloride tube, this system uses a camera to capture red optical density images within an occluded tube and constructs the tube flow channel shape using a formula manipulation system. To verify the accuracy of this system, we compared the thickness of a cross-section of the flow channel constructed with the degree of occlusion quantification system with the thickness of a cross-section of silicone cured under the same occlusion conditions. Our experiments indicated that for areas with a small tube gap, this system can construct highly accurate three-dimensional shapes and obtain quantitative indicators assessing the degree of occlusion.

Characterization of mammographic masses based on local photometric attributes

This paper proposes Local Photometric Attributes (LPA) for the characterization of mammographic masses as benign or malignant. LPA measures the local information over the optical density image which suppresses the background region and provides more details about the mass lesion. The evaluation of the proposed approach is conducted by incorporating the mammograms of two benchmark databases—mini-MIAS and DDSM where a ten-fold cross validation technique is employed with different classifiers—Fishers Linear Discriminant Analysis, Random forest, and Support vector machine after filtering the optimal set of features by utilizing stepwise logistic regression method. The best performance achieved by the introduced approach in terms of an area under the receiver operating characteristic (ROC) curve (Az value) and accuracy (Acc) are 0.94 and 86.90%, respectively for the mini-MIAS dataset while the same for the DDSM dataset are 0.89 and 80.76%, respectively. The competitive nature of the proposed scheme is evident by comparing the obtained results with schemes in the state-of-the-arts.

Neutron attenuation analysis of cryogenic propellants

Neutron imaging enables direct visualization of evaporation and condensation of cryogenic propellants in metal containers such as aluminum and stainless steel. CFD models of propellant behaviors inside the large tanks have shown that a thin liquid film is formed along the interior surface, but this had not been verified experimentally. In the present study, neutron imaging is used to study evaporation and condensation rates of liquid methane inside a cylindrical 10 mm, Al 6061 cell. The liquid meniscus is clearly shown, but the spatial resolution is insufficient to directly image thin liquid films that may be on the interior surface. Optical density (neutron attenuation) analysis enables quantitative measurements of these liquid films. An optical density image is formed by removing the background noise and normalizing the liquid image with that of the empty cell. Optical densities are then transformed into a liquid transmission thickness using the Beer-Lambert law. This technique enables measurement of film thicknesses smaller than the spatial resolution of the imaging system. The above graphic shows an optical density image during condensation of methane and the corresponding horizontal scan which suggests that a 11 μm film exists on the wall. The images indicate that methane undergoes film-wise condensation and is perfectly wetting to aluminum. These experiments were conducted at the NIST Center for Neutron Research in the Neutron Imaging Facility and the relevant work is supported by an Early stage Innovations Grant from NASA's Space Technology Research Grants Program (Grant # NNX14AB05G).

Improving Performance of Breast Cancer Risk Prediction by Incorporating Optical Density Image Feature Analysis: An Assessment

The purpose of this study is to improve accuracy of near-term breast cancer risk prediction by applying a new mammographic image conversion method combined with a two-stage artificial neural network (ANN)-based classification scheme. The dataset included 168 negative mammography screening cases. In developing and testing our new risk model, we first converted the original grayscale value (GV)-based mammographic images into optical density (OD)-based images. For each case, our computer-aided scheme then computed two types of image features representing bilateral asymmetry and the maximum of the image features computed from GV and OD images, respectively. A two-stage classification scheme consisting of three ANNs was developed. The first stage included two ANNs trained using features computed separately from GV and OD images of 138 cases. The second stage included another ANN to fuse the prediction scores produced by two ANNs in the first stage. The risk prediction performance was tested using the rest 30 cases. With the two-stage classification scheme, the computed area under the receiver operating characteristic curve (AUC) was 0.816 ± 0.071, which was significantly higher than the AUC values of 0.669 ± 0.099 and 0.646 ± 0.099 achieved using two ANNs trained using GV features and OD features, respectively (P < .05). This study demonstrated that applying an OD image conversion method can acquire new complimentary information to those acquired from the original images. As a result, fusion image features computed from these two types of images yielded significantly higher performance in near-term breast cancer risk prediction.

Optical density changes in ultrasonographic images of the endometrium and corpus luteum in pregnant and cyclic cows

Optical density image (ODI) analysis, based on the intensity of pixels in digital images, is commonly used in orthopedic medicine. This study was conducted to quantify endometrial and luteal changes in early pregnant and cyclic cows by ODI analysis. Twenty healthy primiparous Simmental cows on days 80?120 postpartum were subjected to ultrasonography and ODI analysis on the days of estrus (day 0) and metestrus (day 4) as well as 12, 15, 18, and 21 days after insemination. The ODI values of pregnant (P) and nonpregnant (NP) cows were compared using two-way ANOVA. The P cows tended to have greater endometrial OD values than NP cows (772.2 vs. 740.5, P < 0.08), but their luteal OD values were similar (596.0 ± 24). Both endometrial and luteal OD values varied over time in different patterns in P and NP cows in relation to gestational events until confirmation. In conclusion, preliminary data, especially endometrial OD values on day 15 relative to insemination, could have prognostic merit for a very early detection or confirmation of pregnancy. ODI analysis can be incorporated into ultrasonographic examination. However, more comprehensive experiments are needed to assure the prognostic value of ODI analysis.

Radiochromic film thickness correction with convergent cone- beam optical CT scanner

A cone-beam optical computed tomography (CT) scanner was modified by replacing the diffuse planar yellow light emitting diode (LED) source with violet and red LEDs and a large Fresnel lens. The narrow band sources provided transmission images of radiochromic EBT2 film at 420 and 633 nm, with air as a reference. The dose image was not detectable with the violet source. This demonstrated spectral independence of the two images. Assuming attenuation at 420 nm was dominated by absorption from yellow dye in the active film layer allowed a relative thickness image to be calculated. By scaling the 633 nm optical density image for relative thickness, non-uniformities in the recorded dose distribution due to film thickness variations, were removed.

SU‐E‐CAMPUS‐T‐06: Radiochromic Film Analysis Based On Principal Components

Purpose:An algorithm to convert the color image of scanned EBT2 radiochromic film [Ashland, Covington KY] into a dose map was developed based upon a principal component analysis. The sensitive layer of the EBT2 film is colored so that the background streaks arising from variations in thickness and scanning imperfections may be distinguished by color from the dose in the exposed film.Methods:Doses of 0, 0.94, 1.9, 3.8, 7.8, 16, 32 and 64 Gy were delivered to radiochromic films by contact with a calibrated Sr‐90/Y‐90 source. They were digitized by a transparency scanner. Optical density images were calculated and analyzed by the method of principal components. The eigenimages of the 0.94 Gy film contained predominantly noise, predominantly background streaking, and background streaking plus the source, respectively, in order from the smallest to the largest eigenvalue. Weighting the second and third eigenimages by −0.574 and 0.819 respectively and summing them plus the constant 0.012 yielded a processed optical density image with negligible background streaking. This same weighted sum was transformed to the red, green and blue space of the scanned images and applied to all of the doses. The curve of processed density in the middle of the source versus applied dose was fit by a twophase association curve. A film was sandwiched between two polystyrene blocks and exposed edge‐on to a different Y‐90 source. This measurement was modeled with the GATE simulation toolkit [Version 6.2, OpenGATE Collaboration], and the on‐axis depth‐dose curves were compared.Results:The transformation defined using the principal component analysis of the 0.94 Gy film minimized streaking in the backgrounds of all of the films. The depth‐dose curves from the film measurement and simulation are indistinguishable.Conclusion:This algorithm accurately converts EBT2 film images to dose images while reducing noise and minimizing background streaking.Supported by a sponsored research agreement from IsoTherapeutics Group, LLC.

The DNA chromatin condensation expressed by the image optical density of chromosomes and heterochromatin in proliferating single human leukemic granulocytic progenitors

Summary The appearance of heterochromatin is generally accepted as a useful tool for the evaluation of the cell state including pathology; however, information on the heterochromatin DNA condensation state expressed by the image optical density in interphase nuclear regions and mitotic chromosomes with silent genes is very limited. Since human proliferating myeloblasts are a very convenient model, they were studied in the bone marrow of leukemic patients and established cell cultures using computer assisted image densitometry at the single cell level after heterochromatin visualization by a simple but sensitive cytochemical procedure for demonstration of DNA. As was expected, a high DNA image optical density was noted in central heterochromatin regions in contrast to the nuclear periphery at the nuclear envelope. Similarly, a high nuclear DNA image optical density was also expressed in mitotic chromosomes. Thus the possibility exists that the large heterochromatin DNA condensation expressed by the large image optical density in central nuclear regions, as in mitotic chromosomes, is related to silent gene locations. The similar width of mitotic chromosomes and chromatin fibrils in the heterochromatin regions in the interphase nuclei supports that explanation. The chromatin DNA fibrils in the central heterochromatin nuclear regions of interphase cells might just represent masked silent chromosomal segments. Such a conclusion is in harmony with “classical” cytology in the first part of the last century, which suggests the chromosome continuity from the mitotic division to the interphase where each chromatin region (“Kernbezirk”) actually represents a chromosomal territory.

Hard-Field THz Tomography

We report on hard-field tomography measurements in the THz spectral range and subsequent image reconstruction of a phantom subject. At THz wavelengths, the traditional hard-field tomography approach to measure attenuation is hindered by a substantial diffusely scattered component. Consequently, we work in optical density image contrast, as opposed to material density typical in high-energy hard-field modalities, such as X-ray CT. The hard-field component of the signal is extracted with a spatial filter, efficiently suppressing the soft-field contributions from the imaged subject. Using time-domain THz spectroscopy, line integrals of the real part of the refractive index are taken, by measuring the delay of the THz pulse across the subject at 12 angles and 0.5 mm steps in the transversal direction for each angle. The delay values are calculated from the location of the first peak in the integrated time-domain waveforms. This is justified by the physics of THz generation with ultrashort pulses in a biased-gap antenna and is shown to be superior to existing alternatives. The resulting tomography projections provide evidence for the hard-field character of the line integrals. The quality of the reconstructed image is interpreted and discussed, together with some limitations and future avenues.

Web-Based Support for Fracture Healing Evaluation and Monitoring

The lack of a universal system for fracture healing progress evaluation recommended by evidence-based orthopedics is mentioned in current literature. Radiographs and the observation of clinical signs and symptoms remain standard practice for the assessment of fracture healing progress. The general aim of this study was to show the main functionalities of the Web-based telediagnostic tools designed to improve fracture healing assessment follow-up and to present a study of fracture healing assessment based on collected study group of long bone fracture cases. The originally designed Web-based system was used to assess remotely fracture healing in 40 complete radiographic sets (211 radiographs) randomly selected from a database. Digital radiographic images and clinical data were stored in the database and then subjected to detailed analysis. Descriptive classifications, scorings, and radiographic image optical density analysis measurements were used for a series of cases. Curves on the graph, drawn from the consecutive follow-up measurements of fracture gap optical density, can slope down regularly in normal healing cases or remain irregular and disorganized in delayed unions. An association between optical density values, callus index, and descriptive scoring variables was found for normal healing based on results received from Web-based telediagnostic system. The development of Web-based telediagnostic applications have the potential to improve fracture qualitative and quantitative evaluation and monitoring for the improvement of the quality of fracture care. The results imply the feasibility of Web-based fracture healing assessment telediagnostic applications over the Internet.

An exposure indicator for digital radiography: AAPM Task Group 116 (Executive Summary)

Digital radiographic imaging systems, such as those using photostimulable storage phosphor, amorphous selenium, amorphous silicon, CCD, and MOSFET technology, can produce adequate image quality over a much broader range of exposure levels than that of screen/film imaging systems. In screen/film imaging, the final image brightness and contrast are indicative of over- and underexposure. In digital imaging, brightness and contrast are often determined entirely by digital postprocessing of the acquired image data. Overexposure and underexposures are not readily recognizable. As a result, patient dose has a tendency to gradually increase over time after a department converts from screen/film-based imaging to digital radiographic imaging. The purpose of this report is to recommend a standard indicator which reflects the radiation exposure that is incident on a detector after every exposure event and that reflects the noise levels present in the image data. The intent is to facilitate the production of consistent, high quality digital radiographic images at acceptable patient doses. This should be based not on image optical density or brightness but on feedback regarding the detector exposure provided and actively monitored by the imaging system. A standard beam calibration condition is recommended that is based on RQA5 but uses filtration materials that are commonly available and simple to use. Recommendations on clinical implementation of the indices to control image quality and patient dose are derived from historical tolerance limits and presented as guidelines.

Three-dimensional mapping of non-complex specimens by image processing and optical density evaluation of digitised radiographs

Digital radiography has been studied extensively for thickness measurement in recent years. This has resulted in enhanced image quality and improved overall evaluation. In this research, an innovative numerical method was used for image enhancement and radiographic interpretation through the use of MATLAB software. Film digitising was carried out by a scanner. Thickness profiles of specimens were extracted from the optical density of radiographs by a numerical method. Therefore, digital imaging and optical density measurements were combined to evaluate the thickness profile of samples. Results were used to create a three-dimensional mapping of the non-complex specimens for further investigation. Then the volumetric information could be used for the evaluation of various defects, such as corrosion, erosion and pitting. The most important challenge in the calculations was measuring the exact effective atomic attenuation coefficient for the samples. For this purpose, some reference blocks were designed, fabricated and used. In addition to practical experiments, Monte Carlo simulation was carried out for accurate assessment of the developed method. Although results show a high correlation between real and calculated values for plates, insulated and non-insulated pipes, this method cannot be used for the volumetric rendering of samples with a complex geometry. Ordinary computerised tomography has to be used for complex specimens.

Statin Therapy Inhibits Remyelination in the Central Nervous System

Remyelination of lesions in the central nervous system contributes to neural repair following clinical relapses in multiple sclerosis. Remyelination is initiated by recruitment and differentiation of oligodendrocyte progenitor cells (OPCs) into myelinating oligodendrocytes. Simvastatin, a blood-brain barrier-permeable statin in multiple sclerosis clinical trials, has been shown to impact the in vitro processes that have been implicated in remyelination. Animals were fed a cuprizone-supplemented diet for 6 weeks to induce localized demyelination in the corpus callosum; subsequent return to normal diet for 3 weeks stimulated remyelination. Simvastatin was injected intraperitoneally during the period of coincident demyelination and OPC maturation (weeks 4 to 6), throughout the entire period of OPC responses (weeks 4 to 9), or during the remyelination-only phase (weeks 7 to 9). Simvastatin treatment (weeks 4 to 6) caused a decrease in myelin load and both Olig2(strong) and Nkx2.2(strong) OPC numbers. Simvastatin treatment (weeks 4 to 9 and 7 to 9) caused a decrease in myelin load, which was correlated with a reduction in Nkx2.2(strong) OPCs and an increase in Olig2(strong) cells, suggesting that OPCs were maintained in an immature state (Olig2(strong)/Nkx2.2(weak)). NogoA+ oligodendrocyte numbers were decreased during all simvastatin treatment regimens. Our findings suggest that simvastatin inhibits central nervous system remyelination by blocking progenitor differentiation, indicating the need to monitor effects of systemic immunotherapies that can access the central nervous system on brain tissue-repair processes.

Cyclical and Dose-Dependent Responses of Adult Human Mature Oligodendrocytes to Fingolimod

Fingolimod is a sphingosine-1-phosphate (S1P) analogue that has been used in clinical trials as a systemic immunomodulatory therapy for multiple sclerosis. Fingolimod readily accesses the central nervous system, raising the issue of its direct effects on neural cells. We assessed the effects of active fingolimod on dissociated cultures of mature, myelin-producing oligodendrocytes (OLGs) derived from adult human brain. Human OLGs express S1P receptor transcripts in relative abundance of S1P5>S1P3>S1P1, with undetectable levels of S1P4. Low doses of fingolimod (100 pmol/L to 1 nmol/L) induced initial membrane elaboration (2 days), subsequent retraction (4 days), and recurrence of extension with prolonged treatment (8 days). Higher doses (10 nmol/L to 1 mumol/L) caused the opposite modulation of membrane dynamics. Retraction was rescued by co-treatment with the S1P3/S1P5 pathway antagonist, suramin, and was associated with RhoA-mediated cytoskeletal signaling. Membrane elaboration was mimicked using the S1P1 agonist SEW2871. Fingolimod rescued human OLGs from serum and glucose deprivation-induced apoptosis, which was reversed with suramin co-treatment and mimicked using an S1P5 agonist. High doses of fingolimod induced an initial down-regulation of S1P5 mRNA levels relative to control (4 hours), subsequent up-regulation (2 days), and recurrent down-regulation (8 days). S1P1 mRNA levels were inversely regulated compared with S1P5. These results indicate that fingolimod modulates maturity- and species-specific OLG membrane dynamics and survival responses that are directly relevant for myelin integrity.

A simple imaging method for biomass determination

An inexpensive and fast method based on images taken during growth of bacterial cells on multi-well plates was developed for biomass quantification. A correlation of 85% between the results obtained by image analysis and optical density measurements was obtained. This simple method allows the assessment of growth with highly aggregated cell cultures and the rapid screening of a large number of carbon sources.

Optimization of standard patient radiographic images for chest, skull and pelvis exams in conventional x-ray equipment

Optimized radiographic techniques for clinical images of chest, skull and pelvis using conventional single-phase, three-phase and high-frequency x-ray units for a standard patient have been developed. Optimization of image contrast and optical density was obtained by using a homogeneous phantom (PEP) and an Anderson Rando anthropomorphic phantom. Image quality was evaluated by nine radiologists in independent analyses, leading to the choice of the optimized technique. A course of action to implement and validate these techniques in other radiographic systems has also been introduced. A realistic-analytic phantom (RAP) was constructed to certify the validation process. The optimized radiographic technique was implemented in the routine of our home hospital radiodiagnostic routine, enabling a reduction in patient doses around 25, 14 and 72%, respectively, for chest, skull and pelvis exams when compared with the previously used techniques. In addition, a corresponding reduction in the x-ray tube load of 68, 14 and 62% for the respective mentioned exams has been observed. In conclusion, implemented optimal techniques can lead to a reduction in the rate of film rejection, thus contributing to a better risk–benefit relationship for the patient and cost–benefit for the radiodiagnostic facility.