Feature maps driven no-reference image quality prediction of authentically distorted images

NASA Astrophysics Data System (ADS)

Ghadiyaram, Deepti; Bovik, Alan C.

2015-03-01

Current blind image quality prediction models rely on benchmark databases comprised of singly and synthetically distorted images, thereby learning image features that are only adequate to predict human perceived visual quality on such inauthentic distortions. However, real world images often contain complex mixtures of multiple distortions. Rather than a) discounting the effect of these mixtures of distortions on an image's perceptual quality and considering only the dominant distortion or b) using features that are only proven to be efficient for singly distorted images, we deeply study the natural scene statistics of authentically distorted images, in different color spaces and transform domains. We propose a feature-maps-driven statistical approach which avoids any latent assumptions about the type of distortion(s) contained in an image, and focuses instead on modeling the remarkable consistencies in the scene statistics of real world images in the absence of distortions. We design a deep belief network that takes model-based statistical image features derived from a very large database of authentically distorted images as input and discovers good feature representations by generalizing over different distortion types, mixtures, and severities, which are later used to learn a regressor for quality prediction. We demonstrate the remarkable competence of our features for improving automatic perceptual quality prediction on a benchmark database and on the newly designed LIVE Authentic Image Quality Challenge Database and show that our approach of combining robust statistical features and the deep belief network dramatically outperforms the state-of-the-art.

Dynamic intensity-weighted region of interest imaging for conebeam CT

PubMed Central

Pearson, Erik; Pan, Xiaochuan; Pelizzari, Charles

2017-01-01

BACKGROUND Patient dose from image guidance in radiotherapy is small compared to the treatment dose. However, the imaging beam is untargeted and deposits dose equally in tumor and healthy tissues. It is desirable to minimize imaging dose while maintaining efficacy. OBJECTIVE Image guidance typically does not require full image quality throughout the patient. Dynamic filtration of the kV beam allows local control of CT image noise for high quality around the target volume and lower quality elsewhere, with substantial dose sparing and reduced scatter fluence on the detector. METHODS The dynamic Intensity-Weighted Region of Interest (dIWROI) technique spatially varies beam intensity during acquisition with copper filter collimation. Fluence is reduced by 95% under the filters with the aperture conformed dynamically to the ROI during cone-beam CT scanning. Preprocessing to account for physical effects of the collimator before reconstruction is described. RESULTS Reconstructions show image quality comparable to a standard scan in the ROI, with higher noise and streak artifacts in the outer region but still adequate quality for patient localization. Monte Carlo modeling shows dose reduction by 10–15% in the ROI due to reduced scatter, and up to 75% outside. CONCLUSIONS The presented technique offers a method to reduce imaging dose by accepting increased image noise outside the ROI, while maintaining full image quality inside the ROI. PMID:27257875

Automatic spectral imaging protocol selection and iterative reconstruction in abdominal CT with reduced contrast agent dose: initial experience.

PubMed

Lv, Peijie; Liu, Jie; Chai, Yaru; Yan, Xiaopeng; Gao, Jianbo; Dong, Junqiang

2017-01-01

To evaluate the feasibility, image quality, and radiation dose of automatic spectral imaging protocol selection (ASIS) and adaptive statistical iterative reconstruction (ASIR) with reduced contrast agent dose in abdominal multiphase CT. One hundred and sixty patients were randomly divided into two scan protocols (n = 80 each; protocol A, 120 kVp/450 mgI/kg, filtered back projection algorithm (FBP); protocol B, spectral CT imaging with ASIS and 40 to 70 keV monochromatic images generated per 300 mgI/kg, ASIR algorithm. Quantitative parameters (image noise and contrast-to-noise ratios [CNRs]) and qualitative visual parameters (image noise, small structures, organ enhancement, and overall image quality) were compared. Monochromatic images at 50 keV and 60 keV provided similar or lower image noise, but higher contrast and overall image quality as compared with 120-kVp images. Despite the higher image noise, 40-keV images showed similar overall image quality compared to 120-kVp images. Radiation dose did not differ between the two protocols, while contrast agent dose in protocol B was reduced by 33 %. Application of ASIR and ASIS to monochromatic imaging from 40 to 60 keV allowed contrast agent dose reduction with adequate image quality and without increasing radiation dose compared to 120 kVp with FBP. • Automatic spectral imaging protocol selection provides appropriate scan protocols. • Abdominal CT is feasible using spectral imaging and 300 mgI/kg contrast agent. • 50-keV monochromatic images with 50 % ASIR provide optimal image quality.

Importance of methodology on (99m)technetium dimercapto-succinic acid scintigraphic image quality: imaging pilot study for RIVUR (Randomized Intervention for Children With Vesicoureteral Reflux) multicenter investigation.

PubMed

Ziessman, Harvey A; Majd, Massoud

2009-07-01

We reviewed our experience with (99m)technetium dimercapto-succinic acid scintigraphy obtained during an imaging pilot study for a multicenter investigation (Randomized Intervention for Children With Vesicoureteral Reflux) of the effectiveness of daily antimicrobial prophylaxis for preventing recurrent urinary tract infection and renal scarring. We analyzed imaging methodology and its relation to diagnostic image quality. (99m)Technetium dimercapto-succinic acid imaging guidelines were provided to participating sites. High-resolution planar imaging with parallel hole or pinhole collimation was required. Two core reviewers evaluated all submitted images. Analysis included appropriate views, presence or lack of patient motion, adequate magnification, sufficient counts and diagnostic image quality. Inter-reader agreement was evaluated. We evaluated 70, (99m)technetium dimercapto-succinic acid studies from 14 institutions. Variability was noted in methodology and image quality. Correlation (r value) between dose administered and patient age was 0.780. For parallel hole collimator imaging good correlation was noted between activity administered and counts (r = 0.800). For pinhole imaging the correlation was poor (r = 0.110). A total of 10 studies (17%) were rejected for quality issues of motion, kidney overlap, inadequate magnification, inadequate counts and poor quality images. The submitting institution was informed and provided with recommendations for improving quality, and resubmission of another study was required. Only 4 studies (6%) were judged differently by the 2 reviewers, and the differences were minor. Methodology and image quality for (99m)technetium dimercapto-succinic acid scintigraphy varied more than expected between institutions. The most common reason for poor image quality was inadequate count acquisition with insufficient attention to the tradeoff between administered dose, length of image acquisition, start time of imaging and resulting image quality. Inter-observer core reader agreement was high. The pilot study ensured good diagnostic quality standardized images for the Randomized Intervention for Children With Vesicoureteral Reflux investigation.

Global quality imaging: improvement actions.

PubMed

Lau, Lawrence S; Pérez, Maria R; Applegate, Kimberly E; Rehani, Madan M; Ringertz, Hans G; George, Robert

2011-05-01

Workforce shortage, workload increase, workplace changes, and budget challenges are emerging issues around the world, which could place quality imaging at risk. It is important for imaging stakeholders to collaborate, ensure patient safety, improve the quality of care, and address these issues. There is no single panacea. A range of improvement measures, strategies, and actions are required. Examples of improvement actions supporting the 3 quality measures are described under 5 strategies: conducting research, promoting awareness, providing education and training, strengthening infrastructure, and implementing policies. The challenge is to develop long-term, cost-effective, system-based improvement actions that will bring better outcomes and underpin a sustainable future for quality imaging. In an imaging practice, these actions will result in selecting the right procedure (justification), using the right dose (optimization), and preventing errors along the patient journey. To realize this vision and implement these improvement actions, a range of expertise and adequate resources are required. Stakeholders should collaborate and work together. In today's globalized environment, collaboration is strength and provides synergy to achieve better outcomes and greater success. Copyright © 2011 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Visual quality analysis for images degraded by different types of noise

NASA Astrophysics Data System (ADS)

Ponomarenko, Nikolay N.; Lukin, Vladimir V.; Ieremeyev, Oleg I.; Egiazarian, Karen O.; Astola, Jaakko T.

2013-02-01

Modern visual quality metrics take into account different peculiarities of the Human Visual System (HVS). One of them is described by the Weber-Fechner law and deals with the different sensitivity to distortions in image fragments with different local mean values (intensity, brightness). We analyze how this property can be incorporated into a metric PSNRHVS- M. It is shown that some improvement of its performance can be provided. Then, visual quality of color images corrupted by three types of i.i.d. noise (pure additive, pure multiplicative, and signal dependent, Poisson) is analyzed. Experiments with a group of observers are carried out for distorted color images created on the basis of TID2008 database. Several modern HVS-metrics are considered. It is shown that even the best metrics are unable to assess visual quality of distorted images adequately enough. The reasons for this deal with the observer's attention to certain objects in the test images, i.e., with semantic aspects of vision, which are worth taking into account in design of HVS-metrics.

Fuzzy intelligent quality monitoring model for X-ray image processing.

PubMed

Khalatbari, Azadeh; Jenab, Kouroush

2009-01-01

Today's imaging diagnosis needs to adapt modern techniques of quality engineering to maintain and improve its accuracy and reliability in health care system. One of the main factors that influences diagnostic accuracy of plain film X-ray on detecting pathology is the level of film exposure. If the level of film exposure is not adequate, a normal body structure may be interpretated as pathology and vice versa. This not only influences the patient management but also has an impact on health care cost and patient's quality of life. Therefore, providing an accurate and high quality image is the first step toward an excellent patient management in any health care system. In this paper, we study these techniques and also present a fuzzy intelligent quality monitoring model, which can be used to keep variables from degrading the image quality. The variables derived from chemical activity, cleaning procedures, maintenance, and monitoring may not be sensed, measured, or calculated precisely due to uncertain situations. Therefore, the gamma-level fuzzy Bayesian model for quality monitoring of an image processing is proposed. In order to apply the Bayesian concept, the fuzzy quality characteristics are assumed as fuzzy random variables. Using the fuzzy quality characteristics, the newly developed model calculates the degradation risk for image processing. A numerical example is also presented to demonstrate the application of the model.

Display challenges resulting from the use of wide field of view imaging devices

NASA Astrophysics Data System (ADS)

Petty, Gregory J.; Fulton, Jack; Nicholson, Gail; Seals, Ean

2012-06-01

As focal plane array technologies advance and imagers increase in resolution, display technology must outpace the imaging improvements in order to adequately represent the complete data collection. Typical display devices tend to have an aspect ratio similar to 4:3 or 16:9, however a breed of Wide Field of View (WFOV) imaging devices exist that skew from the norm with aspect ratios as high as 5:1. This particular quality, when coupled with a high spatial resolution, presents a unique challenge for display devices. Standard display devices must choose between resizing the image data to fit the display and displaying the image data in native resolution and truncating potentially important information. The problem compounds when considering the applications; WFOV high-situationalawareness imagers are sought for space-limited military vehicles. Tradeoffs between these issues are assessed to the image quality of the WFOV sensor.

Real-Time Internet Connections: Implications for Surgical Decision Making in Laparoscopy

PubMed Central

Broderick, Timothy J.; Harnett, Brett M.; Doarn, Charles R.; Rodas, Edgar B.; Merrell, Ronald C.

2001-01-01

Objective To determine whether a low-bandwidth Internet connection can provide adequate image quality to support remote real-time surgical consultation. Summary Background Data Telemedicine has been used to support care at a distance through the use of expensive equipment and broadband communication links. In the past, the operating room has been an isolated environment that has been relatively inaccessible for real-time consultation. Recent technological advances have permitted videoconferencing over low-bandwidth, inexpensive Internet connections. If these connections are shown to provide adequate video quality for surgical applications, low-bandwidth telemedicine will open the operating room environment to remote real-time surgical consultation. Methods Surgeons performing a laparoscopic cholecystectomy in Ecuador or the Dominican Republic shared real-time laparoscopic images with a panel of surgeons at the parent university through a dial-up Internet account. The connection permitted video and audio teleconferencing to support real-time consultation as well as the transmission of real-time images and store-and-forward images for observation by the consultant panel. A total of six live consultations were analyzed. In addition, paired local and remote images were “grabbed” from the video feed during these laparoscopic cholecystectomies. Nine of these paired images were then placed into a Web-based tool designed to evaluate the effect of transmission on image quality. Results The authors showed for the first time the ability to identify critical anatomic structures in laparoscopy over a low-bandwidth connection via the Internet. The consultant panel of surgeons correctly remotely identified biliary and arterial anatomy during six laparoscopic cholecystectomies. Within the Web-based questionnaire, 15 surgeons could not blindly distinguish the quality of local and remote laparoscopic images. Conclusions Low-bandwidth, Internet-based telemedicine is inexpensive, effective, and almost ubiquitous. Use of these inexpensive, portable technologies will allow sharing of surgical procedures and decisions regardless of location. Internet telemedicine consistently supported real-time intraoperative consultation in laparoscopic surgery. The implications are broad with respect to quality improvement and diffusion of knowledge as well as for basic consultation. PMID:11505061

Generation of complementary sampled phase-only holograms.

PubMed

Tsang, P W M; Chow, Y T; Poon, T-C

2016-10-03

If an image is uniformly down-sampled into a sparse form and converted into a hologram, the phase component alone will be adequate to reconstruct the image. However, the appearance of the reconstructed image is degraded with numerous empty holes. In this paper, we present a low complexity and non-iterative solution to this problem. Briefly, two phase-only holograms are generated for an image, each based on a different down-sampling lattice. Subsequently, the holograms are displayed alternately at high frame rate. The reconstructed images of the 2 holograms will appear to be a single, densely sampled image with enhance visual quality.

Measurement Invariance of the Appearance Schemas Inventory-Revised and the Body Image Quality of Life Inventory across Age and Gender

ERIC Educational Resources Information Center

Rusticus, Shayna A.; Hubley, Anita M.; Zumbo, Bruno D.

2008-01-01

The majority of body image measures have largely been developed with younger female samples. Before these measures can be applied to men, and to middle-aged and older women, and used to make gender and age comparisons, they must exhibit adequate cross-group measurement invariance. This study examined the age and gender cross-group measurement…

Preclinical imaging characteristics and quantification of Platinum-195m SPECT.

PubMed

Aalbersberg, E A; de Wit-van der Veen, B J; Zwaagstra, O; Codée-van der Schilden, K; Vegt, E; Vogel, Wouter V

2017-08-01

In vivo biodistribution imaging of platinum-based compounds may allow better patient selection for treatment with chemo(radio)therapy. Radiolabeling with Platinum-195m ( 195m Pt) allows SPECT imaging, without altering the chemical structure or biological activity of the compound. We have assessed the feasibility of 195m Pt SPECT imaging in mice, with the aim to determine the image quality and accuracy of quantification for current preclinical imaging equipment. Enriched (>96%) 194 Pt was irradiated in the High Flux Reactor (HFR) in Petten, The Netherlands (NRG). A 0.05 M HCl 195m Pt-solution with a specific activity of 33 MBq/mg was obtained. Image quality was assessed for the NanoSPECT/CT (Bioscan Inc., Washington DC, USA) and U-SPECT + /CT (MILabs BV, Utrecht, the Netherlands) scanners. A radioactivity-filled rod phantom (rod diameter 0.85-1.7 mm) filled with 1 MBq 195m Pt was scanned with different acquisition durations (10-120 min). Four healthy mice were injected intravenously with 3-4 MBq 195m Pt. Mouse images were acquired with the NanoSPECT for 120 min at 0, 2, 4, or 24 h after injection. Organs were delineated to quantify 195m Pt concentrations. Immediately after scanning, the mice were sacrificed, and the platinum concentration was determined in organs using a gamma counter and graphite furnace - atomic absorption spectroscopy (GF-AAS) as reference standards. A 30-min acquisition of the phantom provided visually adequate image quality for both scanners. The smallest visible rods were 0.95 mm in diameter on the NanoSPECT and 0.85 mm in diameter on the U-SPECT + . The image quality in mice was visually adequate. Uptake was seen in the kidneys with excretion to the bladder, and in the liver, blood, and intestine. No uptake was seen in the brain. The Spearman correlation between SPECT and gamma counter was 0.92, between SPECT and GF-AAS it was 0.84, and between GF-AAS and gamma counter it was0.97 (all p < 0.0001). Preclinical 195m Pt SPECT is feasible with acceptable tracer doses and acquisition times, and provides good image quality and accurate signal quantification.

Dose and diagnostic image quality in digital tomosynthesis imaging of facial bones in pediatrics

NASA Astrophysics Data System (ADS)

King, J. M.; Hickling, S.; Elbakri, I. A.; Reed, M.; Wrogemann, J.

2011-03-01

The purpose of this study was to evaluate the use of digital tomosynthesis (DT) for pediatric facial bone imaging. We compared the eye lens dose and diagnostic image quality of DT facial bone exams relative to digital radiography (DR) and computed tomography (CT), and investigated whether we could modify our current DT imaging protocol to reduce patient dose while maintaining sufficient diagnostic image quality. We measured the dose to the eye lens for all three modalities using high-sensitivity thermoluminescent dosimeters (TLDs) and an anthropomorphic skull phantom. To assess the diagnostic image quality of DT compared to the corresponding DR and CT images, we performed an observer study where the visibility of anatomical structures in the DT phantom images were rated on a four-point scale. We then acquired DT images at lower doses and had radiologists indicate whether the visibility of each structure was adequate for diagnostic purposes. For typical facial bone exams, we measured eye lens doses of 0.1-0.4 mGy for DR, 0.3-3.7 mGy for DT, and 26 mGy for CT. In general, facial bone structures were visualized better with DT then DR, and the majority of structures were visualized well enough to avoid the need for CT. DT imaging provides high quality diagnostic images of the facial bones while delivering significantly lower doses to the lens of the eye compared to CT. In addition, we found that by adjusting the imaging parameters, the DT effective dose can be reduced by up to 50% while maintaining sufficient image quality.

Quantitative Analysis of the Effect of Iterative Reconstruction Using a Phantom: Determining the Appropriate Blending Percentage

PubMed Central

Kim, Hyun Gi; Lee, Young Han; Choi, Jin-Young; Park, Mi-Suk; Kim, Myeong-Jin; Kim, Ki Whang

2015-01-01

Purpose To investigate the optimal blending percentage of adaptive statistical iterative reconstruction (ASIR) in a reduced radiation dose while preserving a degree of image quality and texture that is similar to that of standard-dose computed tomography (CT). Materials and Methods The CT performance phantom was scanned with standard and dose reduction protocols including reduced mAs or kVp. Image quality parameters including noise, spatial, and low-contrast resolution, as well as image texture, were quantitatively evaluated after applying various blending percentages of ASIR. The optimal blending percentage of ASIR that preserved image quality and texture compared to standard dose CT was investigated in each radiation dose reduction protocol. Results As the percentage of ASIR increased, noise and spatial-resolution decreased, whereas low-contrast resolution increased. In the texture analysis, an increasing percentage of ASIR resulted in an increase of angular second moment, inverse difference moment, and correlation and in a decrease of contrast and entropy. The 20% and 40% dose reduction protocols with 20% and 40% ASIR blending, respectively, resulted in an optimal quality of images with preservation of the image texture. Conclusion Blending the 40% ASIR to the 40% reduced tube-current product can maximize radiation dose reduction and preserve adequate image quality and texture. PMID:25510772

Facilitation of receptive and productive foreign vocabulary learning using the keyword method: the role of image quality.

PubMed

Beaton, Alan A; Gruneberg, Michael M; Hyde, Christopher; Shufflebottom, Alex; Sykes, Robert N

2005-07-01

Ellis and Beaton (1993a) reported that the keyword method of learning enhanced memory of foreign vocabulary items when receptive learning was measured. However, for productive learning, rote repetition was superior to the keyword method. The first two experiments reported here show that, in comparison with rote repetition, both receptive and productive learning can be enhanced by the keyword method, provided that the quality of the keyword images is adequate. In a third experiment using a subset of words from Ellis and Beaton (1993a), the finding they reported, that for productive learning rote repetition was superior to the keyword method, was reversed. The quality of keyword images will vary from study to study and any generalisation regarding the efficacy of the keyword method must take this into account.

How much image noise can be added in cardiac x-ray imaging without loss in perceived image quality?

NASA Astrophysics Data System (ADS)

Gislason-Lee, Amber J.; Kumcu, Asli; Kengyelics, Stephen M.; Rhodes, Laura A.; Davies, Andrew G.

2015-03-01

Dynamic X-ray imaging systems are used for interventional cardiac procedures to treat coronary heart disease. X-ray settings are controlled automatically by specially-designed X-ray dose control mechanisms whose role is to ensure an adequate level of image quality is maintained with an acceptable radiation dose to the patient. Current commonplace dose control designs quantify image quality by performing a simple technical measurement directly from the image. However, the utility of cardiac X-ray images is in their interpretation by a cardiologist during an interventional procedure, rather than in a technical measurement. With the long term goal of devising a clinically-relevant image quality metric for an intelligent dose control system, we aim to investigate the relationship of image noise with clinical professionals' perception of dynamic image sequences. Computer-generated noise was added, in incremental amounts, to angiograms of five different patients selected to represent the range of adult cardiac patient sizes. A two alternative forced choice staircase experiment was used to determine the amount of noise which can be added to a patient image sequences without changing image quality as perceived by clinical professionals. Twenty-five viewing sessions (five for each patient) were completed by thirteen observers. Results demonstrated scope to increase the noise of cardiac X-ray images by up to 21% +/- 8% before it is noticeable by clinical professionals. This indicates a potential for 21% radiation dose reduction since X-ray image noise and radiation dose are directly related; this would be beneficial to both patients and personnel.

Improvement of ablative margins by the intraoperative use of CEUS-CT/MR image fusion in hepatocellular carcinoma.

PubMed

Li, Kai; Su, Zhong-Zhen; Xu, Er-Jiao; Ju, Jin-Xiu; Meng, Xiao-Chun; Zheng, Rong-Qin

2016-04-18

To assess whether intraoperative use of contrast-enhanced ultrasound (CEUS)-CT/MR image fusion can accurately evaluate ablative margin (AM) and guide supplementary ablation to improve AM after hepatocellular carcinoma (HCC) ablation. Ninety-eight patients with 126 HCCs designated to undergo thermal ablation treatment were enrolled in this prospective study. CEUS-CT/MR image fusion was performed intraoperatively to evaluate whether 5-mm AM was covered by the ablative area. If possible, supplementary ablation was applied at the site of inadequate AM. The CEUS image quality, the time used for CEUS-CT/MR image fusion and the success rate of image fusion were recorded. Local tumor progression (LTP) was observed during follow-up. Clinical factors including AM were examined to identify risk factors for LTP. The success rate of image fusion was 96.2% (126/131), and the duration required for image fusion was 4.9 ± 2.0 (3-13) min. The CEUS image quality was good in 36.1% (53/147) and medium in 63.9% (94/147) of the cases. By supplementary ablation, 21.8% (12/55) of lesions with inadequate AMs became adequate AMs. During follow-up, there were 5 LTPs in lesions with inadequate AMs and 1 LTP in lesions with adequate AMs. Multivariate analysis showed that AM was the only independent risk factor for LTP (hazard ratio, 9.167; 95% confidence interval, 1.070-78.571; p = 0.043). CEUS-CT/MR image fusion is feasible for intraoperative use and can serve as an accurate method to evaluate AMs and guide supplementary ablation to lower inadequate AMs.

New Imaging Strategies Using a Motion-Resistant Liver Sequence in Uncooperative Patients

PubMed Central

Kim, Bong Soo; Lee, Kyung Ryeol; Goh, Myeng Ju

2014-01-01

MR imaging has unique benefits for evaluating the liver because of its high-resolution capability and ability to permit detailed assessment of anatomic lesions. In uncooperative patients, motion artifacts can impair the image quality and lead to the loss of diagnostic information. In this setting, the recent advances in motion-resistant liver MR techniques, including faster imaging protocols (e.g., dual-echo magnetization-prepared rapid-acquisition gradient echo (MP-RAGE), view-sharing technique), the data under-sampling (e.g., gradient recalled echo (GRE) with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA), single-shot echo-train spin-echo (SS-ETSE)), and motion-artifact minimization method (e.g., radial GRE with/without k-space-weighted image contrast (KWIC)), can provide consistent, artifact-free images with adequate image quality and can lead to promising diagnostic performance. Understanding of the different motion-resistant options allows radiologists to adopt the most appropriate technique for their clinical practice and thereby significantly improve patient care. PMID:25243115

Comparing the efficacy and safety between propofol and dexmedetomidine for sedation in claustrophobic adults undergoing magnetic resonance imaging (PADAM trial).

PubMed

Loh, Pui-San; Ariffin, Mohd Azlan; Rai, Vineya; Lai, Lee-Lee; Chan, Lucy; Ramli, Norlisah

2016-11-01

To determine the efficacy of sedation with dexmedetomidine compared to propofol for claustrophobic adults undergoing magnetic resonance imaging (MRI) in our institution. Randomized, prospective, double-blinded study. University-based tertiary referral center. Thirty claustrophobic adults with American Society of Anesthesiologists physical status I and II who were planned for MRI. Patients were randomly assigned to target-controlled infusion propofol or dexmedetomidine loading followed by maintenance dose for procedural sedation. The primary end point was adequate reduction in patient anxiety levels to allow successful completion of the MRI sequence. Both methods of sedation adequately reduced anxiety levels in visual analog scale scores and Spielberger Strait Test Anxiety Inventory (P<.001). Dexmedetomidine required a longer time to achieve anxiolysis, 7.36minutes (SD, 2.59), and required increasing maintenance dose to induce sleep compared to 10.71minutes (SD, 4.63) for propofol. In terms of image quality, 2 patients (16.67%) in the dexmedetomidine group were satisfactory, whereas all with propofol were graded as good to excellent. Adverse effects were seen in patients sedated with dexmedetomidine with number needed to harm 8 for hypotension and 15 for bradycardia compared to none recorded in the propofol arm. There was no significant difference in patient satisfaction scores or home readiness after the MRI. Both dexmedetomidine and propofol can effectively reduce anxiety levels of claustrophobic adults undergoing MRI, but dexmedetomidine takes longer to achieve adequate anxiolysis and sleep and may have an effect on image quality. Hypotension and bradycardia are common adverse effects observed with dexmedetomidine. Copyright © 2016 Elsevier Inc. All rights reserved.

Reevaluation of JPEG image compression to digitalized gastrointestinal endoscopic color images: a pilot study

NASA Astrophysics Data System (ADS)

Kim, Christopher Y.

1999-05-01

Endoscopic images p lay an important role in describing many gastrointestinal (GI) disorders. The field of radiology has been on the leading edge of creating, archiving and transmitting digital images. With the advent of digital videoendoscopy, endoscopists now have the ability to generate images for storage and transmission. X-rays can be compressed 30-40X without appreciable decline in quality. We reported results of a pilot study using JPEG compression of 24-bit color endoscopic images. For that study, the result indicated that adequate compression ratios vary according to the lesion and that images could be compressed to between 31- and 99-fold smaller than the original size without an appreciable decline in quality. The purpose of this study was to expand upon the methodology of the previous sty with an eye towards application for the WWW, a medium which would expand both clinical and educational purposes of color medical imags. The results indicate that endoscopists are able to tolerate very significant compression of endoscopic images without loss of clinical image quality. This finding suggests that even 1 MB color images can be compressed to well under 30KB, which is considered a maximal tolerable image size for downloading on the WWW.

Body image and quality of life in a Spanish population

PubMed Central

Lobera, Ignacio Jáuregui; Ríos, Patricia Bolaños

2011-01-01

Purpose The aim of the current study was to analyze the psychometric properties, factor structure, and internal consistency of the Spanish version of the Body Image Quality of Life Inventory (BIQLI-SP) as well as its test–retest reliability. Further objectives were to analyze different relationships with key dimensions of psychosocial functioning (ie, self-esteem, presence of psychopathological symptoms, eating and body image-related problems, and perceived stress) and to evaluate differences in body image quality of life due to gender. Patients and methods The sample comprised 417 students without any psychiatric history, recruited from the Pablo de Olavide University and the University of Seville. There were 140 men (33.57%) and 277 women (66.43%), and the mean age was 21.62 years (standard deviation = 5.12). After obtaining informed consent from all participants, the following questionnaires were administered: BIQLI, Eating Disorder Inventory-2 (EDI-2), Perceived Stress Questionnaire (PSQ), Self-Esteem Scale (SES), and Symptom Checklist-90-Revised (SCL-90-R). Results The BIQLI-SP shows adequate psychometric properties, and it may be useful to determine the body image quality of life in different physical conditions. A more positive body image quality of life is associated with better self-esteem, better psychological wellbeing, and fewer eating-related dysfunctional attitudes, this being more evident among women. Conclusion The BIQLI-SP may be useful to determine the body image quality of life in different contexts with regard to dermatology, cosmetic and reconstructive surgery, and endocrinology, among others. In these fields of study, a new trend has emerged to assess body image-related quality of life. PMID:21403794

Trabecular bone analysis in CT and X-ray images of the proximal femur for the assessment of local bone quality.

PubMed

Fritscher, Karl; Grunerbl, Agnes; Hanni, Markus; Suhm, Norbert; Hengg, Clemens; Schubert, Rainer

2009-10-01

Currently, conventional X-ray and CT images as well as invasive methods performed during the surgical intervention are used to judge the local quality of a fractured proximal femur. However, these approaches are either dependent on the surgeon's experience or cannot assist diagnostic and planning tasks preoperatively. Therefore, in this work a method for the individual analysis of local bone quality in the proximal femur based on model-based analysis of CT- and X-ray images of femur specimen will be proposed. A combined representation of shape and spatial intensity distribution of an object and different statistical approaches for dimensionality reduction are used to create a statistical appearance model in order to assess the local bone quality in CT and X-ray images. The developed algorithms are tested and evaluated on 28 femur specimen. It will be shown that the tools and algorithms presented herein are highly adequate to automatically and objectively predict bone mineral density values as well as a biomechanical parameter of the bone that can be measured intraoperatively.

Twin robotic x-ray system for 2D radiographic and 3D cone-beam CT imaging

NASA Astrophysics Data System (ADS)

Fieselmann, Andreas; Steinbrener, Jan; Jerebko, Anna K.; Voigt, Johannes M.; Scholz, Rosemarie; Ritschl, Ludwig; Mertelmeier, Thomas

2016-03-01

In this work, we provide an initial characterization of a novel twin robotic X-ray system. This system is equipped with two motor-driven telescopic arms carrying X-ray tube and flat-panel detector, respectively. 2D radiographs and fluoroscopic image sequences can be obtained from different viewing angles. Projection data for 3D cone-beam CT reconstruction can be acquired during simultaneous movement of the arms along dedicated scanning trajectories. We provide an initial evaluation of the 3D image quality based on phantom scans and clinical images. Furthermore, initial evaluation of patient dose is conducted. The results show that the system delivers high image quality for a range of medical applications. In particular, high spatial resolution enables adequate visualization of bone structures. This system allows 3D X-ray scanning of patients in standing and weight-bearing position. It could enable new 2D/3D imaging workflows in musculoskeletal imaging and improve diagnosis of musculoskeletal disorders.

Image quality and artefact generation post-cerebral aneurysm clipping using a 64-row multislice computer tomography angiography (MSCTA) technology: A retrospective study and review of the literature.

PubMed

Zachenhofer, Iris; Cejna, Manfred; Schuster, Antonius; Donat, Markus; Roessler, Karl

2010-06-01

Computed tomography angiography (CTA) is a time and cost saving investigation for postoperative evaluation of clipped cerebral aneurysm patients. A retrospective study was conducted to analyse image quality and artefact generation due to implanted aneurysm clips using a new technology. MSCTA was performed pre- and postoperatively using a Philips Brilliance 64-detector-row CT scanner. Altogether, 32 clipping sites were analysed in 27 patients (11 female and 16 male, mean ages 52a, from 24 to 72 years). Clip number per aneurysm was 2.3 mean (from 1 to 4), 54 clips were made of titanium alloy and 5 of cobalt alloy. Altogether, image quality was rated 1.8 mean, using a scale from 1 (very good) to 5 (unserviceable) and clip artefacts were rated 2.4 mean, using a 5 point rating scale (1 no artefacts, 5 unserviceable due to artefacts). A significant loss of image quality and rise of artefacts was found when using cobalt alloy clips (1.4 versus 4.2 and 2.1 versus 4.0). In 72% of all investigations, an excellent image quality was found. Excluding the cobalt clip group, 85% of scans showed excellent image quality. Artefacts were absent or minimal (grade 1 or 2) in 69% of all investigations and in 81% in the pure titanium clip group. In 64-row MSCTA of good image quality with low artefacts, it was possible to detect small aneurysm remnants of 2mm size in individual patients. By using titanium alloy clips, in our study up to 85% of postoperative CTA images were of excellent quality with absent or minimal artefacts in 81% and seem adequate to detect small aneurysm remnants. Copyright 2010 Elsevier B.V. All rights reserved.

Improving the diagnostic quality and adequacy of shoulder radiographs in a District General Hospital

PubMed Central

Richards, Bethany; Riley, James; Saithna, Adnan

2016-01-01

A high rate of suboptimal shoulder radiographs was identified during a service evaluation exercise in our orthopaedic outpatient clinics. Inadequate radiographs require a return to the radiology department for further imaging, a resultant increased workload, delays in the clinic, increased radiation for patients, and inconvenience and decreased patient satisfaction. Furthermore, if a sub-optimal radiograph is accepted there is concern that diagnoses may be missed. The aim of this project was to decrease the rate of suboptimal radiographs by delivering a teaching package directed towards quality improvement. Evaluation criteria were set for standard orthopaedic shoulder radiographs (Anterior-posterior, axillary, and Velpeau views). Baseline data collection was performed over three, two-week periods and included all patients attending the shoulder clinic. The percentage of x-rays which were deemed adequate was only 19.4% for anterior-posterior views and 57.9% for axillary views. A comprehensive educational package was delivered to radiographers. This included a formal PowerPoint based teaching session, hands on training with practice using a skeleton, posters with step-by step instructions on how to obtain an adequate image, and PDF aide memoires suitable for viewing on a smartphone. Two subsequent two-week periods of data collection were performed to evaluate the benefit of this intervention. Delivery of focussed training and provision of easily accessible aide memoires to facilitate improved quality of radiographs resulted in a significant (p<0.05) reduction in the rate of inadequate images. There was also a significant decreases in the rate of return to the radiology department for repeat imaging. PMID:27559473

Comparison of pediatric radiation dose and vessel visibility on angiographic systems using piglets as a surrogate: antiscatter grid removal vs. lower detector air kerma settings with a grid — a preclinical investigation

PubMed Central

Racadio, John M.; Abruzzo, Todd A.; Johnson, Neil D.; Patel, Manish N.; Kukreja, Kamlesh U.; den Hartog, Mark. J. H.; Hoornaert, Bart P.A.; Nachabe, Rami A.

2015-01-01

The purpose of this study was to reduce pediatric doses while maintaining or improving image quality scores without removing the grid from X‐ray beam. This study was approved by the Institutional Animal Care and Use Committee. Three piglets (5, 14, and 20 kg) were imaged using six different selectable detector air kerma (Kair) per frame values (100%, 70%, 50%, 35%, 25%, 17.5%) with and without the grid. Number of distal branches visualized with diagnostic confidence relative to the injected vessel defined image quality score. Five pediatric interventional radiologists evaluated all images. Image quality score and piglet Kair were statistically compared using analysis of variance and receiver operating curve analysis to define the preferred dose setting and use of grid for a visibility of 2nd and 3rd order vessel branches. Grid removal reduced both dose to subject and imaging quality by 26%. Third order branches could only be visualized with the grid present; 100% detector Kair was required for smallest pig, while 70% detector Kair was adequate for the two larger pigs. Second order branches could be visualized with grid at 17.5% detector Kair for all three pig sizes. Without the grid, 50%, 35%, and 35% detector Kair were required for smallest to largest pig, respectively. Grid removal reduces both dose and image quality score. Image quality scores can be maintained with less dose to subject with the grid in the beam as opposed to removed. Smaller anatomy requires more dose to the detector to achieve the same image quality score. PACS numbers: 87.53.Bn, 87.57.N‐, 87.57.cj, 87.59.cf, 87.59.Dj PMID:26699297

A systematic review on the quality of measurement techniques for the assessment of burn wound depth or healing potential.

PubMed

Jaspers, Mariëlle E H; van Haasterecht, Ludo; van Zuijlen, Paul P M; Mokkink, Lidwine B

2018-06-22

Reliable and valid assessment of burn wound depth or healing potential is essential to treatment decision-making, to provide a prognosis, and to compare studies evaluating different treatment modalities. The aim of this review was to critically appraise, compare and summarize the quality of relevant measurement properties of techniques that aim to assess burn wound depth or healing potential. A systematic literature search was performed using PubMed, EMBASE and Cochrane Library. Two reviewers independently evaluated the methodological quality of included articles using an adapted version of the Consensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist. A synthesis of evidence was performed to rate the measurement properties for each technique and to draw an overall conclusion on quality of the techniques. Thirty-six articles were included, evaluating various techniques, classified as (1) laser Doppler techniques; (2) thermography or thermal imaging; (3) other measurement techniques. Strong evidence was found for adequate construct validity of laser Doppler imaging (LDI). Moderate evidence was found for adequate construct validity of thermography, videomicroscopy, and spatial frequency domain imaging (SFDI). Only two studies reported on the measurement property reliability. Furthermore, considerable variation was observed among comparator instruments. Considering the evidence available, it appears that LDI is currently the most favorable technique; thereby assessing burn wound healing potential. Additional research is needed into thermography, videomicroscopy, and SFDI to evaluate their full potential. Future studies should focus on reliability and measurement error, and provide a precise description of which construct is aimed to measure. Copyright © 2018 Elsevier Ltd and ISBI. All rights reserved.

Use of a 1.0 Tesla open scanner for evaluation of pediatric and congenital heart disease: a retrospective cohort study.

PubMed

Lu, Jimmy C; Nielsen, James C; Morowitz, Layne; Musani, Muzammil; Ghadimi Mahani, Maryam; Agarwal, Prachi P; Ibrahim, El-Sayed H; Dorfman, Adam L

2015-05-25

Open cardiovascular magnetic resonance (CMR) scanners offer the potential for imaging patients with claustrophobia or large body size, but at a lower 1.0 Tesla magnetic field. This study aimed to evaluate the efficacy of open CMR for evaluation of pediatric and congenital heart disease. This retrospective, cross-sectional study included all patients ≤18 years old or with congenital heart disease who underwent CMR on an open 1.0 Tesla scanner at two centers from 2012-2014. Indications for CMR and clinical questions were extracted from the medical record. Studies were qualitatively graded for image quality and diagnostic utility. In a subset of 25 patients, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were compared to size- and diagnosis-matched patients with CMR on a 1.5 Tesla scanner. A total of 65 patients (median 17.3 years old, 60% male) were included. Congenital heart disease was present in 32 (50%), with tetralogy of Fallot and bicuspid aortic valve the most common diagnoses. Open CMR was used due to scheduling/equipment issues in 51 (80%), claustrophobia in 7 (11%), and patient size in 3 (5%); 4 patients with claustrophobia had failed CMR on a different scanner, but completed the study on open CMR without sedation. All patients had good or excellent image quality on black blood, phase contrast, magnetic resonance angiography, and late gadolinium enhancement imaging. There was below average image quality in 3/63 (5%) patients with cine images, and 4/15 (27%) patients with coronary artery imaging. SNR and CNR were decreased in cine and magnetic resonance angiography images compared to 1.5 Tesla. The clinical question was answered adequately in all but 2 patients; 1 patient with a Fontan had artifact from an embolization coil limiting RV volume analysis, and in 1 patient the right coronary artery origin was not well seen. Open 1.0 Tesla scanners can effectively evaluate pediatric and congenital heart disease, including patients with claustrophobia and larger body size. Despite minor artifacts and differences in SNR and CNR, the majority of clinical questions can be answered adequately, with some limitations with coronary artery imaging. Further evaluation is necessary to optimize protocols and image quality.

Prestack depth migration for complex 2D structure using phase-screen propagators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, P.; Huang, Lian-Jie; Burch, C.

1997-11-01

We present results for the phase-screen propagator method applied to prestack depth migration of the Marmousi synthetic data set. The data were migrated as individual common-shot records and the resulting partial images were superposed to obtain the final complete Image. Tests were performed to determine the minimum number of frequency components required to achieve the best quality image and this in turn provided estimates of the minimum computing time. Running on a single processor SUN SPARC Ultra I, high quality images were obtained in as little as 8.7 CPU hours and adequate images were obtained in as little as 4.4more » CPU hours. Different methods were tested for choosing the reference velocity used for the background phase-shift operation and for defining the slowness perturbation screens. Although the depths of some of the steeply dipping, high-contrast features were shifted slightly the overall image quality was fairly insensitive to the choice of the reference velocity. Our jests show the phase-screen method to be a reliable and fast algorithm for imaging complex geologic structures, at least for complex 2D synthetic data where the velocity model is known.« less

High sensitive fundus autofluorescence imaging combined with speckle-free optical coherence tomography

NASA Astrophysics Data System (ADS)

Stremplewski, Patrycjusz; Komar, Katarzyna; Szkulmowski, Maciej; Motoczyńska, Marta; Wojtkowski, Maciej

2013-03-01

Scattering and fluorescence images provide complementary information about the health condition of the human eye, so getting them in a single measurement, using a single device may significantly improve a quality of diagnosis as it has been already demonstrated in Spectralis (Heidelberg Eng.) OCT instrument. There is still challenge to improve quality of fundus autofluorescence (FAF) images. The biggest obstacle in obtaining in vivo images of sufficient quality is very low fluorescence signal. For eye safety reasons, and because of patient comfort, using highpower fluorescence excitation is not an adequate solution to the low signal problem. In this contribution we show a new detection method in the retinal autofluorescence imaging, which may improve the sensitivity. We used a fast modulated (up to 500 MHz) diode laser of wavelength 473 nm and detected fluorescence in the spectral range 500-680 nm by photomultiplier and lock-in amplifier. Average power of the collimated blue beam on the cornea used for FAF measurements was set to 50 μW, 10 μW, and even 4.5 μW.

An Audit to Evaluate the Image Quality of Magnetic Resonance of Knee at Radiology Department of a Tertiary Care Hospital.

PubMed

Mansoor, Ali; Ramzan, Amaila; Chaudhary, Aamer Nadeem

2017-04-01

light of recommendations of ACR. Aclinical audit. Department of Radiology, Jinnah Hospital, Lahore, from August 2015 to February 2016. Scans of 20 patients who underwent MRI of knee in August 2015 were studied retrospectively to assess the quality of images obtained in the first audit. Based on the findings of this audit, recommendations were made and re audit was done 6 months later in February 2016 to look for improvement in local practice. In the first audit, images were acquired in all the three necessary planes and the sagittal and coronal images had appropriate slice thickness, interslice gap as well as adequate anatomical coverage in all the patients. However, FOV (field of view) was appropriately set in 66% of cases in axial plane, 5% in sagittal plane, and 0% in coronal plane. Also, the anatomical coverage was not upto the mark in axial plane with 13 studies (66%) having adequate superior coverage, and 16 cases (80%) having recommended inferior anatomical coverage. The re audit performed 6 months later showed improvement with 100% compliance to standards. The first audit showed many shortcomings in acquiring of MRI data in patients undergoing knee MRI with FOV requiring a decrease in all planes and anatomical coverage increase in axial plane. These recommendations were made in departmental meetings and re-audit was done after 6 months. This second audit showed 100 % compliance.

Rapid sequence magnetic resonance imaging in the assessment of children with hydrocephalus.

PubMed

O'Neill, Brent R; Pruthi, Sumit; Bains, Harmanjeet; Robison, Ryan; Weir, Keiko; Ojemann, Jeff; Ellenbogen, Richard; Avellino, Anthony; Browd, Samuel R

2013-12-01

Recent reports have shown the utility of rapid-acquisition magnetic resonance imaging (MRI) in the evaluation of children with hydrocephalus. Rapid sequence MRI (RS-MRI) acquires clinically useful images in seconds without exposing children to the risks of ionizing radiation or sedation. We review our experience with RS-MRI in children with shunts. Overall image quality, cost, catheter visualization, motion artifact, and ventricular size were reviewed for all RS-MRI studies obtained at Seattle Children's Hospital during a 2-year period. Image acquisition time was 12-19 seconds, with sessions usually lasting less than 3 minutes. Image quality was very good or excellent in 94% of studies, whereas only one was graded as poor. Significant motion artifact was noted in 7%, whereas 77% had little or no motion artifact. Catheter visualization was good or excellent in 57%, poor in 36%, and misleading in 7%. Small ventricular size was correlated with poor catheter visualization (Spearman's ρ = 0.586; P < 0.00001). RS-MRI imaging cost ∼$650 more than conventional computed tomography (CT). Our study supports that RS-MRI is an adequate substitute that allows reduced use of CT imaging and resultant exposure to ionizing radiation. Catheter position visualization remains suboptimal when ventricles are small, but shunt malfunction can be adequately determined in most cases. The cost is significantly more than CT, but the potential for lifetime reduction in radiation exposure may justify this expense in children. Limitations include the risk of valve malfunction after repeated exposure to high magnetic fields and the need for reprogramming with many types of adjustable valves. Copyright © 2013 Elsevier Inc. All rights reserved.

Incorporating digital imaging into dental hygiene practice.

PubMed

Saxe, M J; West, D J

1997-01-01

The objective of this paper is to describe digital imaging technology: available modalities, scientific imaging process, advantages and limitations, and applications to dental hygiene practice. Advances in technology have created innovative imaging modalities for intraoral radiography that eliminate film as the traditional image receptor. Digital imaging generates instantaneous radiographic images on a display monitor following exposure. Advantages include lower patient exposure per image and elimination of film processing. Digital imaging enhances diagnostic capabilities and, therefore, treatment decisions by the oral healthcare provider. Utilization of digital imaging technology for intraoral radiography will advance the practice of dental hygiene. Although spatial resolution is inferior to conventional film, digital imaging provides adequate resolution to diagnose oral diseases. Dental hygienists must evaluate new technologies in radiography to continue providing quality care while reducing patient exposure to ionizing radiation.

Virtual dissection of Thoropa miliaris tadpole using phase-contrast synchrotron microtomography

NASA Astrophysics Data System (ADS)

Fidalgo, G.; Colaço, M. V.; Nogueira, L. P.; Braz, D.; Silva, H. R.; Colaço, G.; Barroso, R. C.

2018-05-01

In this work, in-line phase-contrast synchrotron microtomography was used in order to study the external and internal morphology of Thoropa miliaris tadpoles. Whole-specimens of T. miliaris in larval stages of development 28, 37 and 42, collected in the municipality of Mangaratiba (Rio de Janeiro, Brazil) were used for the study. The samples were scanned in microtomography beamline (IMX) at the Brazilian Synchrotron Light Laboratory (LNLS). The phase-contrast technique allowed us to obtain high quality images which made possible the structures segmentation on the rendered volume by the Avizo graphic image editing software. The combination of high quality images and segmentation process provides adequate visualization of different organs and soft (liver, notochord, brain, crystalline, cartilages) and hard (elements of the bone skeleton) tissues.

Radiation protection program for early detection of breast cancer in a mammography facility

NASA Astrophysics Data System (ADS)

Villagomez Casimiro, Mariana; Ruiz Trejo, Cesar; Espejo Fonseca, Ruby

2014-11-01

Mammography is the best tool for early detection of Breast Cancer. In this diagnostic radiology modality it is necessary to establish the criteria to ensure the proper use and operation of the equipment used to obtain mammographic images in order to contribute to the safe use of ionizing radiation. The aim of the work was to implement at FUCAM-AC the radiation protection program which must be established for patients and radiation workers according to Mexican standards [1-4]. To achieve this goal, radiation protection and quality control manuals were elaborated [5]. Furthermore, a quality control program (QCP) in the mammography systems (analog/digital), darkroom included, has been implemented. Daily sensitometry, non-variability of the image quality, visualizing artifacts, revision of the equipment mechanical stability, compression force and analysis of repetition studies are some of the QCP routine tests that must be performed by radiological technicians of this institution as a set of actions to ensure the protection of patients. Image quality and patients dose assessment were performed on 4 analog equipment installed in 2 mobile units. In relation to dose assessment, all equipment passed the acceptance criteria (<3 mGy per projection). The image quality test showed that most images (70%)- presented artifacts. A brief summary of the results of quality control tests applied to the equipment and film processor are presented. To maintain an adequate level of quality and safety at FUCAM-AC is necessary that the proposed radiation protection program in this work is applied.

Dedicated dental volumetric and total body multislice computed tomography: a comparison of image quality and radiation dose

NASA Astrophysics Data System (ADS)

Strocchi, Sabina; Colli, Vittoria; Novario, Raffaele; Carrafiello, Gianpaolo; Giorgianni, Andrea; Macchi, Aldo; Fugazzola, Carlo; Conte, Leopoldo

2007-03-01

Aim of this work is to compare the performances of a Xoran Technologies i-CAT Cone Beam CT for dental applications with those of a standard total body multislice CT (Toshiba Aquilion 64 multislice) used for dental examinations. Image quality and doses to patients have been compared for the three main i-CAT protocols, the Toshiba standard protocol and a Toshiba modified protocol. Images of two phantoms have been acquired: a standard CT quality control phantom and an Alderson Rando ® anthropomorphic phantom. Image noise, Signal to Noise Ratio (SNR), Contrast to Noise Ratio (CNR) and geometric accuracy have been considered. Clinical image quality was assessed. Effective dose and doses to main head and neck organs were evaluated by means of thermo-luminescent dosimeters (TLD-100) placed in the anthropomorphic phantom. A Quality Index (QI), defined as the ratio of squared CNR to effective dose, has been evaluated. The evaluated effective doses range from 0.06 mSv (i-CAT 10 s protocol) to 2.37 mSv (Toshiba standard protocol). The Toshiba modified protocol (halved tube current, higher pitch value) imparts lower effective dose (0.99 mSv). The conventional CT device provides lower image noise and better SNR, but clinical effectiveness similar to that of dedicated dental CT (comparable CNR and clinical judgment). Consequently, QI values are much higher for this second CT scanner. No geometric distortion has been observed with both devices. As a conclusion, dental volumetric CT supplies adequate image quality to clinical purposes, at doses that are really lower than those imparted by a conventional CT device.

Evaluation of a cone beam computed tomography geometry for image guided small animal irradiation.

PubMed

Yang, Yidong; Armour, Michael; Wang, Ken Kang-Hsin; Gandhi, Nishant; Iordachita, Iulian; Siewerdsen, Jeffrey; Wong, John

2015-07-07

The conventional imaging geometry for small animal cone beam computed tomography (CBCT) is that a detector panel rotates around the head-to-tail axis of an imaged animal ('tubular' geometry). Another unusual but possible imaging geometry is that the detector panel rotates around the anterior-to-posterior axis of the animal ('pancake' geometry). The small animal radiation research platform developed at Johns Hopkins University employs the pancake geometry where a prone-positioned animal is rotated horizontally between an x-ray source and detector panel. This study is to assess the CBCT image quality in the pancake geometry and investigate potential methods for improvement. We compared CBCT images acquired in the pancake geometry with those acquired in the tubular geometry when the phantom/animal was placed upright simulating the conventional CBCT geometry. Results showed signal-to-noise and contrast-to-noise ratios in the pancake geometry were reduced in comparison to the tubular geometry at the same dose level. But the overall spatial resolution within the transverse plane of the imaged cylinder/animal was better in the pancake geometry. A modest exposure increase to two folds in the pancake geometry can improve image quality to a level close to the tubular geometry. Image quality can also be improved by inclining the animal, which reduces streak artifacts caused by bony structures. The major factor resulting in the inferior image quality in the pancake geometry is the elevated beam attenuation along the long axis of the phantom/animal and consequently increased scatter-to-primary ratio in that orientation. Not withstanding, the image quality in the pancake-geometry CBCT is adequate to support image guided animal positioning, while providing unique advantages of non-coplanar and multiple mice irradiation. This study also provides useful knowledge about the image quality in the two very different imaging geometries, i.e. pancake and tubular geometry, respectively.

Evaluation of a Cone Beam Computed Tomography Geometry for Image Guided Small Animal Irradiation

PubMed Central

Yang, Yidong; Armour, Michael; Wang, Ken Kang-Hsin; Gandhi, Nishant; Iordachita, Iulian; Siewerdsen, Jeffrey; Wong, John

2015-01-01

The conventional imaging geometry for small animal cone beam computed tomography (CBCT) is that a detector panel rotates around the head-to-tail axis of an imaged animal (“tubular” geometry). Another unusual but possible imaging geometry is that the detector panel rotates around the anterior-to-posterior axis of the animal (“pancake” geometry). The small animal radiation research platform (SARRP) developed at Johns Hopkins University employs the pancake geometry where a prone-positioned animal is rotated horizontally between an x-ray source and detector panel. This study is to assess the CBCT image quality in the pancake geometry and investigate potential methods for improvement. We compared CBCT images acquired in the pancake geometry with those acquired in the tubular geometry when the phantom/animal was placed upright simulating the conventional CBCT geometry. Results showed signal-to-noise and contrast-to-noise ratios in the pancake geometry were reduced in comparison to the tubular geometry at the same dose level. But the overall spatial resolution within the transverse plane of the imaged cylinder/animal was better in the pancake geometry. A modest exposure increase to two folds in the pancake geometry can improve image quality to a level close to the tubular geometry. Image quality can also be improved by inclining the animal, which reduces streak artifacts caused by bony structures. The major factor resulting in the inferior image quality in the pancake geometry is the elevated beam attenuation along the long axis of the phantom/animal and consequently increased scatter-to-primary ratio in that orientation. Notwithstanding, the image quality in the pancake-geometry CBCT is adequate to support image guided animal positioning, while providing unique advantages of non-coplanar and multiple mice irradiation. This study also provides useful knowledge about the image quality in the two very different imaging geometries, i.e., pancake and tubular geometry, respectively. PMID:26083659

Pediatric digital chest imaging.

PubMed

Tarver, R D; Cohen, M; Broderick, N J; Conces, D J

1990-01-01

The Philips Computed Radiography system performs well with pediatric portable chest radiographs, handling the throughout of a busy intensive care service 24 hours a day. Images are excellent and routinely provide a conventional (unenhanced) image and an edge-enhanced image. Radiation dose is decreased by the lowered frequency of repeat examinations and the ability of the plates to respond to a much lower dose and still provide an adequate image. The high quality and uniform density of serial PCR portable radiographs greatly enhances diagnostic content of the films. Decreased resolution has not been a problem clinically. Image manipulation and electronic transfer to remote viewing stations appear to be helpful and are currently being evaluated further. The PCR system provides a marked improvement in pediatric portable chest radiology.

Development of a telediagnosis endoscopy system over secure internet.

PubMed

Ohashi, K; Sakamoto, N; Watanabe, M; Mizushima, H; Tanaka, H

2008-01-01

We developed a new telediagnosis system to securely transmit high-quality endoscopic moving images over the Internet in real time. This system would enable collaboration between physicians seeking advice from endoscopists separated by long distances, to facilitate diagnosis. We adapted a new type of digital video streaming system (DVTS) to our teleendoscopic diagnosis system. To investigate its feasibility, we conducted a two-step experiment. A basic experiment was first conducted to transmit endoscopic video images between hospitals using a plain DVTS. After investigating the practical usability, we incorporated a secure and reliable communication function into the system, by equipping DVTS with "TCP2", a new security technology that establishes secure communication in the transport layer. The second experiment involved international transmission of teleendoscopic image between Hawaii and Japan using the improved system. In both the experiments, no serious transmission delay was observed to disturb physicians' communications and, after subjective evaluation by endoscopists, the diagnostic qualities of the images were found to be adequate. Moreover, the second experiment showed that "TCP2-equipped DVTS" successfully executed high-quality secure image transmission over a long distance network. We conclude that DVTS technology would be promising for teleendoscopic diagnosis. It was also shown that a high quality, secure teleendoscopic diagnosis system can be developed by equipping DVTS with TCP2.

An exposure indicator for digital radiography: AAPM Task Group 116 (executive summary).

PubMed

Shepard, S Jeff; Wang, Jihong; Flynn, Michael; Gingold, Eric; Goldman, Lee; Krugh, Kerry; Leong, David L; Mah, Eugene; Ogden, Kent; Peck, Donald; Samei, Ehsan; Wang, Jihong; Willis, Charles E

2009-07-01

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.

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

PubMed Central

Shepard, S. Jeff; Wang, Jihong; Flynn, Michael; Gingold, Eric; Goldman, Lee; Krugh, Kerry; Leong, David L.; Mah, Eugene; Ogden, Kent; Peck, Donald; Samei, Ehsan; Wang, Jihong; Willis, Charles E.

2009-01-01

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. PMID:19673189

Characteristics of the retinal images of the eye optical systems with implanted intraocular lenses

NASA Astrophysics Data System (ADS)

Siedlecki, Damian; Zając, Marek; Nowak, Jerzy

2007-04-01

Cataract, or opacity of crystalline lens in the human eye is one of the most frequent reasons of blindness nowadays. Removing the pathologically altered crystalline lens and replacing it with artificial implantable intraocular lens (IOL) is practically the only therapy in this illness. There exist a wide variety of artificial IOL types on the medical market, differing in their material and design (shape). In this paper six exemplary models of IOL's made of PMMA, acrylic and silicone are considered. The retinal image quality is analyzed numerically on the basis of Liou-Brennan eye model with these IOL's inserted. Chromatic aberration as well as polychromatic Point Spread Function and Modulation Transfer Function are calculated as most adequate image quality measures. The calculations made with Zemax TM software show the importance of chromatic aberration correction.

Web-based video monitoring of CT and MRI procedures

NASA Astrophysics Data System (ADS)

Ratib, Osman M.; Dahlbom, Magdalena; Kho, Hwa T.; Valentino, Daniel J.; McCoy, J. Michael

2000-05-01

A web-based video transmission of images from CT and MRI consoles was implemented in an Intranet environment for real- time monitoring of ongoing procedures. Images captured from the consoles are compressed to video resolution and broadcasted through a web server. When called upon, the attending radiologists can view these live images on any computer within the secured Intranet network. With adequate compression, these images can be displayed simultaneously in different locations at a rate of 2 to 5 images/sec through standard LAN. The quality of the images being insufficient for diagnostic purposes, our users survey showed that they were suitable for supervising a procedure, positioning the imaging slices and for routine quality checking before completion of a study. The system was implemented at UCLA to monitor 9 CTs and 6 MRIs distributed in 4 buildings. This system significantly improved the radiologists productivity by saving precious time spent in trips between reading rooms and examination rooms. It also improved patient throughput by reducing the waiting time for the radiologists to come to check a study before moving the patient from the scanner.

Analysis of the impact of digital watermarking on computer-aided diagnosis in medical imaging.

PubMed

Garcia-Hernandez, Jose Juan; Gomez-Flores, Wilfrido; Rubio-Loyola, Javier

2016-01-01

Medical images (MI) are relevant sources of information for detecting and diagnosing a large number of illnesses and abnormalities. Due to their importance, this study is focused on breast ultrasound (BUS), which is the main adjunct for mammography to detect common breast lesions among women worldwide. On the other hand, aiming to enhance data security, image fidelity, authenticity, and content verification in e-health environments, MI watermarking has been widely used, whose main goal is to embed patient meta-data into MI so that the resulting image keeps its original quality. In this sense, this paper deals with the comparison of two watermarking approaches, namely spread spectrum based on the discrete cosine transform (SS-DCT) and the high-capacity data-hiding (HCDH) algorithm, so that the watermarked BUS images are guaranteed to be adequate for a computer-aided diagnosis (CADx) system, whose two principal outcomes are lesion segmentation and classification. Experimental results show that HCDH algorithm is highly recommended for watermarking medical images, maintaining the image quality and without introducing distortion into the output of CADx. Copyright © 2015 Elsevier Ltd. All rights reserved.

Echocardiographic Image Quality Deteriorates with Age in Children and Young Adults with Duchenne Muscular Dystrophy.

PubMed

Power, Alyssa; Poonja, Sabrina; Disler, Dal; Myers, Kimberley; Patton, David J; Mah, Jean K; Fine, Nowell M; Greenway, Steven C

2017-01-01

Advances in medical care for patients with Duchenne muscular dystrophy (DMD) have resulted in improved survival and an increased prevalence of cardiomyopathy. Serial echocardiographic surveillance is recommended to detect early cardiac dysfunction and initiate medical therapy. Clinical anecdote suggests that echocardiographic quality diminishes over time, impeding accurate assessment of left ventricular systolic function. Furthermore, evidence-based guidelines for the use of cardiac imaging in DMD, including cardiac magnetic resonance imaging (CMR), are limited. The objective of our single-center, retrospective study was to quantify the deterioration in echocardiographic image quality with increasing patient age and identify an age at which CMR should be considered. We retrospectively reviewed and graded the image quality of serial echocardiograms obtained in young patients with DMD. The quality of 16 left ventricular segments in two echocardiographic views was visually graded using a binary scoring system. An endocardial border delineation percentage (EBDP) score was calculated by dividing the number of segments with adequate endocardial delineation in each imaging window by the total number of segments present in that window and multiplying by 100. Linear regression analysis was performed to model the relationship between the EBDP scores and patient age. Fifty-five echocardiograms from 13 patients (mean age 11.6 years, range 3.6-19.9) were systematically reviewed. By 13 years of age, 50% of the echocardiograms were classified as suboptimal with ≥30% of segments inadequately visualized, and by 15 years of age, 78% of studies were suboptimal. Linear regression analysis revealed a negative correlation between patient age and EBDP score ( r  = -2.49, 95% confidence intervals -4.73, -0.25; p  = 0.032), with the score decreasing by 2.5% for each 1 year increase in age. Echocardiographic image quality declines with increasing age in DMD. Alternate imaging modalities may play a role in cases of poor echocardiographic image quality.

Construction of anthropomorphic hybrid, dual-lattice voxel models for optimizing image quality and dose in radiography

NASA Astrophysics Data System (ADS)

Petoussi-Henss, Nina; Becker, Janine; Greiter, Matthias; Schlattl, Helmut; Zankl, Maria; Hoeschen, Christoph

2014-03-01

In radiography there is generally a conflict between the best image quality and the lowest possible patient dose. A proven method of dosimetry is the simulation of radiation transport in virtual human models (i.e. phantoms). However, while the resolution of these voxel models is adequate for most dosimetric purposes, they cannot provide the required organ fine structures necessary for the assessment of the imaging quality. The aim of this work is to develop hybrid/dual-lattice voxel models (called also phantoms) as well as simulation methods by which patient dose and image quality for typical radiographic procedures can be determined. The results will provide a basis to investigate by means of simulations the relationships between patient dose and image quality for various imaging parameters and develop methods for their optimization. A hybrid model, based on NURBS (Non Linear Uniform Rational B-Spline) and PM (Polygon Mesh) surfaces, was constructed from an existing voxel model of a female patient. The organs of the hybrid model can be then scaled and deformed in a non-uniform way i.e. organ by organ; they can be, thus, adapted to patient characteristics without losing their anatomical realism. Furthermore, the left lobe of the lung was substituted by a high resolution lung voxel model, resulting in a dual-lattice geometry model. "Dual lattice" means in this context the combination of voxel models with different resolution. Monte Carlo simulations of radiographic imaging were performed with the code EGS4nrc, modified such as to perform dual lattice transport. Results are presented for a thorax examination.

Radiation protection program for early detection of breast cancer in a mammography facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mariana, Villagomez Casimiro, E-mail: marjim10-66@ciencias.unam.mx, E-mail: cesar@fisica.unam.mx; Cesar, Ruiz Trejo, E-mail: marjim10-66@ciencias.unam.mx, E-mail: cesar@fisica.unam.mx; Ruby, Espejo Fonseca

Mammography is the best tool for early detection of Breast Cancer. In this diagnostic radiology modality it is necessary to establish the criteria to ensure the proper use and operation of the equipment used to obtain mammographic images in order to contribute to the safe use of ionizing radiation. The aim of the work was to implement at FUCAM-AC the radiation protection program which must be established for patients and radiation workers according to Mexican standards [1–4]. To achieve this goal, radiation protection and quality control manuals were elaborated [5]. Furthermore, a quality control program (QCP) in the mammography systemsmore » (analog/digital), darkroom included, has been implemented. Daily sensitometry, non-variability of the image quality, visualizing artifacts, revision of the equipment mechanical stability, compression force and analysis of repetition studies are some of the QCP routine tests that must be performed by radiological technicians of this institution as a set of actions to ensure the protection of patients. Image quality and patients dose assessment were performed on 4 analog equipment installed in 2 mobile units. In relation to dose assessment, all equipment passed the acceptance criteria (<3 mGy per projection). The image quality test showed that most images (70%)– presented artifacts. A brief summary of the results of quality control tests applied to the equipment and film processor are presented. To maintain an adequate level of quality and safety at FUCAM-AC is necessary that the proposed radiation protection program in this work is applied.« less

Image quality stability of whole-body diffusion weighted imaging.

PubMed

Chen, Yun-bin; Hu, Chun-miao; Zhong, Jing; Sun, Fei

2009-06-01

To assess the reproducibility of whole-body diffusion weighted imaging (WB-DWI) technique in healthy volunteers under normal breathing with background body signal suppression. WB-DWI was performed on 32 healthy volunteers twice within two-week period using short TI inversion-recovery diffusion-weighted echo-planar imaging sequence and built-in body coil. The volunteers were scanned across six stations continuously covering the entire body from the head to the feet under normal breathing. The bone apparent diffusion coefficient (ADC) and exponential ADC (eADC) of regions of interest (ROIs) were measured. We analyzed correlation of the results using paired-t-test to assess the reproducibility of the WB-DWI technique. We were successful in collecting and analyzing data of 64 WB-DWI images. There was no significant difference in bone ADC and eADC of 824 ROIs between the paired observers and paired scans (P>0.05). Most of the images from all stations were of diagnostic quality. The measurements of bone ADC and eADC have good reproducibility. WB-DWI technique under normal breathing with background body signal suppression is adequate.

Qualitative evaluations and comparisons of six night-vision colorization methods

NASA Astrophysics Data System (ADS)

Zheng, Yufeng; Reese, Kristopher; Blasch, Erik; McManamon, Paul

2013-05-01

Current multispectral night vision (NV) colorization techniques can manipulate images to produce colorized images that closely resemble natural scenes. The colorized NV images can enhance human perception by improving observer object classification and reaction times especially for low light conditions. This paper focuses on the qualitative (subjective) evaluations and comparisons of six NV colorization methods. The multispectral images include visible (Red-Green- Blue), near infrared (NIR), and long wave infrared (LWIR) images. The six colorization methods are channel-based color fusion (CBCF), statistic matching (SM), histogram matching (HM), joint-histogram matching (JHM), statistic matching then joint-histogram matching (SM-JHM), and the lookup table (LUT). Four categries of quality measurements are used for the qualitative evaluations, which are contrast, detail, colorfulness, and overall quality. The score of each measurement is rated from 1 to 3 scale to represent low, average, and high quality, respectively. Specifically, high contrast (of rated score 3) means an adequate level of brightness and contrast. The high detail represents high clarity of detailed contents while maintaining low artifacts. The high colorfulness preserves more natural colors (i.e., closely resembles the daylight image). Overall quality is determined from the NV image compared to the reference image. Nine sets of multispectral NV images were used in our experiments. For each set, the six colorized NV images (produced from NIR and LWIR images) are concurrently presented to users along with the reference color (RGB) image (taken at daytime). A total of 67 subjects passed a screening test ("Ishihara Color Blindness Test") and were asked to evaluate the 9-set colorized images. The experimental results showed the quality order of colorization methods from the best to the worst: CBCF < SM < SM-JHM < LUT < JHM < HM. It is anticipated that this work will provide a benchmark for NV colorization and for quantitative evaluation using an objective metric such as objective evaluation index (OEI).

Design of a multimodal fibers optic system for small animal optical imaging.

PubMed

Spinelli, Antonello E; Pagliazzi, Marco; Boschi, Federico

2015-02-01

Small animals optical imaging systems are widely used in pre-clinical research to image in vivo the bio-distribution of light emitting probes using fluorescence or bioluminescence modalities. In this work we presented a set of simulated results of a novel small animal optical imaging module based on a fibers optics matrix, coupled with a position sensitive detector, devoted to acquire bioluminescence and Cerenkov images. Simulations were performed using GEANT 4 code with the GAMOS architecture using the tissue optics plugin. Results showed that it is possible to image a 30 × 30 mm region of interest using a fiber optics array containing 100 optical fibers without compromising the quality of the reconstruction. The number of fibers necessary to cover an adequate portion of a small animal is thus quite modest. This design allows integrating the module with magnetic resonance (MR) in order to acquire optical and MR images at the same time. A detailed model of the mouse anatomy, obtained by segmentation of 3D MRI images, will improve the quality of optical 3D reconstruction. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Image Quality and Radiation Dose for Prospectively Triggered Coronary CT Angiography: 128-Slice Single-Source CT versus First-Generation 64-Slice Dual-Source CT

NASA Astrophysics Data System (ADS)

Gu, Jin; Shi, He-Shui; Han, Ping; Yu, Jie; Ma, Gui-Na; Wu, Sheng

2016-10-01

This study sought to compare the image quality and radiation dose of coronary computed tomography angiography (CCTA) from prospectively triggered 128-slice CT (128-MSCT) versus dual-source 64-slice CT (DSCT). The study was approved by the Medical Ethics Committee at Tongji Medical College of Huazhong University of Science and Technology. Eighty consecutive patients with stable heart rates lower than 70 bpm were enrolled. Forty patients were scanned with 128-MSCT, and the other 40 patients were scanned with DSCT. Two radiologists independently assessed the image quality in segments (diameter >1 mm) according to a three-point scale (1: excellent; 2: moderate; 3: insufficient). The CCTA radiation dose was calculated. Eighty patients with 526 segments in the 128-MSCT group and 544 segments in the DSCT group were evaluated. The image quality 1, 2 and 3 scores were 91.6%, 6.9% and 1.5%, respectively, for the 128-MSCT group and 97.6%, 1.7% and 0.7%, respectively, for the DSCT group, and there was a statistically significant inter-group difference (P ≤ 0.001). The effective doses were 3.0 mSv in the 128-MSCT group and 4.5 mSv in the DSCT group (P ≤ 0.001). Compared with DSCT, CCTA with prospectively triggered 128-MSCT had adequate image quality and a 33.3% lower radiation dose.

Concept of Operations Evaluation for Using Remote-Guidance Ultrasound for Exploration Spaceflight.

PubMed

Hurst, Victor W; Peterson, Sean; Garcia, Kathleen; Ebert, Douglas; Ham, David; Amponsah, David; Dulchavsky, Scott

2015-12-01

Remote-guidance (RG) techniques aboard the International Space Station (ISS) have enabled astronauts to collect diagnostic-level ultrasound (US) images. Exploration-class missions will likely require nonformally trained sonographers to operate with greater autonomy given longer communication delays (> 6 s for missions beyond the Moon) and blackouts. Training requirements for autonomous collection of US images by non-US experts are being determined. Novice US operators were randomly assigned to one of three groups to collect standardized US images while drawing expertise from A) RG only, B) a computer training tool only, or C) both RG and a computer training tool. Images were assessed for quality and examination duration. All operators were given a 10-min standardized generic training session in US scanning. The imaging task included: 1) bone fracture assessment in a phantom and 2) Focused Assessment with Sonography in Trauma (FAST) examination in a healthy volunteer. A human factors questionnaire was also completed. Mean time for group B during FAST was shorter (20.4 vs. 22.7 min) than time for the other groups. Image quality scoring was lower than in groups A or C, but all groups produced images of acceptable diagnostic quality. RG produces US images of higher quality than those produced with only computer-based instruction. Extended communication delays in exploration missions will eliminate the option of real-time guidance, thus requiring autonomous operation. The computer program used appears effective and could be a model for future digital US expertise banks. Terrestrially, it also provides adequate self-training and mentoring mechanisms.

Smart light random memory sprays Retinex: a fast Retinex implementation for high-quality brightness adjustment and color correction.

PubMed

Banić, Nikola; Lončarić, Sven

2015-11-01

Removing the influence of illumination on image colors and adjusting the brightness across the scene are important image enhancement problems. This is achieved by applying adequate color constancy and brightness adjustment methods. One of the earliest models to deal with both of these problems was the Retinex theory. Some of the Retinex implementations tend to give high-quality results by performing local operations, but they are computationally relatively slow. One of the recent Retinex implementations is light random sprays Retinex (LRSR). In this paper, a new method is proposed for brightness adjustment and color correction that overcomes the main disadvantages of LRSR. There are three main contributions of this paper. First, a concept of memory sprays is proposed to reduce the number of LRSR's per-pixel operations to a constant regardless of the parameter values, thereby enabling a fast Retinex-based local image enhancement. Second, an effective remapping of image intensities is proposed that results in significantly higher quality. Third, the problem of LRSR's halo effect is significantly reduced by using an alternative illumination processing method. The proposed method enables a fast Retinex-based image enhancement by processing Retinex paths in a constant number of steps regardless of the path size. Due to the halo effect removal and remapping of the resulting intensities, the method outperforms many of the well-known image enhancement methods in terms of resulting image quality. The results are presented and discussed. It is shown that the proposed method outperforms most of the tested methods in terms of image brightness adjustment, color correction, and computational speed.

A Macintosh-Based Scientific Images Video Analysis System

NASA Technical Reports Server (NTRS)

Groleau, Nicolas; Friedland, Peter (Technical Monitor)

1994-01-01

A set of experiments was designed at MIT's Man-Vehicle Laboratory in order to evaluate the effects of zero gravity on the human orientation system. During many of these experiments, the movements of the eyes are recorded on high quality video cassettes. The images must be analyzed off-line to calculate the position of the eyes at every moment in time. To this aim, I have implemented a simple inexpensive computerized system which measures the angle of rotation of the eye from digitized video images. The system is implemented on a desktop Macintosh computer, processes one play-back frame per second and exhibits adequate levels of accuracy and precision. The system uses LabVIEW, a digital output board, and a video input board to control a VCR, digitize video images, analyze them, and provide a user friendly interface for the various phases of the process. The system uses the Concept Vi LabVIEW library (Graftek's Image, Meudon la Foret, France) for image grabbing and displaying as well as translation to and from LabVIEW arrays. Graftek's software layer drives an Image Grabber board from Neotech (Eastleigh, United Kingdom). A Colour Adapter box from Neotech provides adequate video signal synchronization. The system also requires a LabVIEW driven digital output board (MacADIOS II from GW Instruments, Cambridge, MA) controlling a slightly modified VCR remote control used mainly to advance the video tape frame by frame.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strauss, K; Nachabe, R; Racadio, J

Purpose: To define an alternative to antiscatter grid (ASG) removal in angiographic systems which achieves similar patient dose reduction as ASG removal without degrading image quality during pediatric imaging. Methods: This study was approved by the local institution animal care and use committee (IACUC). Six different digital subtraction angiography settings were evaluated that altered the mAs, (100, 70, 50, 35, 25, 17.5% of reference mAs) with and without ASG. Three pigs of 5, 15, and 20 kg (9, 15, and 17 cm abdominal thickness; smaller than a newborn, average 3 yr old, and average 10 year old human abdomen respectively)more » were imaged using the six dose settings with and without ASG. Image quality was defined as the order of vessel branch that is visible relative to the injected vessel. Five interventional radiologists evaluated all images. Image quality and patient dose were statistically compared using analysis of variance and receiver operating curve (ROC) analysis to define the preferred dose level and use of ASG for a minimum visibility of 2nd or 3rd order branches of vessel visibility. Results: ASG grid removal reduces dose by 26% with reduced image quality. Only with the ASG present can 3rd order branches be visualized; 100% mAs is required for 9 cm pig while 70% mAs is adequate for the larger pigs. 2nd order branches can be visualized with ASG at 17.5% mAs for all three pig sizes. Without the ASG, 50%, 35% and 35% mAs is required for smallest to largest pig. Conclusion: Removing ASG reduces patient dose and image quality. Image quality can be improved with the ASG present while further reducing patient dose if an optimized radiographic technique is used. Rami Nachabe is an employee of Philips Health Care; Keith Strauss is a paid consultant of Philips Health Care.« less

Clinical Feasibility of Free-Breathing Dynamic T1-Weighted Imaging With Gadoxetic Acid-Enhanced Liver Magnetic Resonance Imaging Using a Combination of Variable Density Sampling and Compressed Sensing.

PubMed

Yoon, Jeong Hee; Yu, Mi Hye; Chang, Won; Park, Jin-Young; Nickel, Marcel Dominik; Son, Yohan; Kiefer, Berthold; Lee, Jeong Min

2017-10-01

The purpose of the study was to investigate the clinical feasibility of free-breathing dynamic T1-weighted imaging (T1WI) using Cartesian sampling, compressed sensing, and iterative reconstruction in gadoxetic acid-enhanced liver magnetic resonance imaging (MRI). This retrospective study was approved by our institutional review board, and the requirement for informed consent was waived. A total of 51 patients at high risk of breath-holding failure underwent dynamic T1WI in a free-breathing manner using volumetric interpolated breath-hold (BH) examination with compressed sensing reconstruction (CS-VIBE) and hard gating. Timing, motion artifacts, and image quality were evaluated by 4 radiologists on a 4-point scale. For patients with low image quality scores (<3) on the late arterial phase, respiratory motion-resolved (extradimension [XD]) reconstruction was additionally performed and reviewed in the same manner. In addition, in 68.6% (35/51) patients who had previously undergone liver MRI, image quality and motion artifacts on dynamic phases using CS-VIBE were compared with previous BH-T1WIs. In all patients, adequate arterial-phase timing was obtained at least once. Overall image quality of free-breathing T1WI was 3.30 ± 0.59 on precontrast and 2.68 ± 0.70, 2.93 ± 0.65, and 3.30 ± 0.49 on early arterial, late arterial, and portal venous phases, respectively. In 13 patients with lower than average image quality (<3) on the late arterial phase, motion-resolved reconstructed T1WI (XD-reconstructed CS-VIBE) significantly reduced motion artifacts (P < 0.002-0.021) and improved image quality (P < 0.0001-0.002). In comparison with previous BH-T1WI, CS-VIBE with hard gating or XD reconstruction showed less motion artifacts and better image quality on precontrast, arterial, and portal venous phases (P < 0.0001-0.013). Volumetric interpolated breath-hold examination with compressed sensing has the potential to provide consistent, motion-corrected free-breathing dynamic T1WI for liver MRI in patients at high risk of breath-holding failure.

Effects of silicone expanders and implants on echocardiographic image quality after breast reconstruction.

PubMed

Pignatti, Marco; Mantovani, Francesca; Bertelli, Luca; Barbieri, Andrea; Pacchioni, Lucrezia; Loschi, Pietro; De Santis, Giorgio

2013-08-01

Use of silicone expanders and implants is the most common breast reconstruction technique after mastectomy. Postmastectomy patients often need echocardiographic monitoring of potential cardiotoxicity induced by cancer chemotherapy. The impairment of the echocardiographic acoustic window caused by silicone implants for breast augmentation has been reported. This study investigates whether the echocardiographic image quality was impaired in women reconstructed with silicone expanders and implants. The records of 44 consecutive women who underwent echocardiographic follow-up after breast reconstruction with expanders and implants at the authors' institution from January of 2000 to August of 2012 were reviewed. The population was divided into a study group (left or bilateral breast expanders/implants, n=30) and a control group (right breast expanders/implants, n=14). The impact of breast expanders/implants on echocardiographic image quality was tested (analysis of covariance model). Patients with a breast expander/implant (left or bilateral and right breast expanders/implants) were included. The mean volume of the breast devices was 353.2±125.5 cc. The quality of the echocardiographic images was good or sufficient in the control group; in the study group, it was judged as adequate in only 50 percent of cases (15 patients) and inadequate in the remaining 15 patients (p<0.001). At multivariable analysis, a persistent relationship between device position (left versus right) and image quality (p=0.001) was shown, independent from other factors. Silicone expanders and implants in postmastectomy left breast reconstruction considerably reduce the image quality of echocardiography. This may have important clinical implications, given the need for periodic echocardiographic surveillance before and during chemotherapy. Therapeutic, III.

Fixed-flexion knee radiography using a new positioning device produced highly repeatable measurements of joint space width: ELSA-Brasil Musculoskeletal Study (ELSA-Brasil MSK).

PubMed

Telles, Rosa Weiss; Costa-Silva, Luciana; Machado, Luciana A C; Reis, Rodrigo Citton Padilha Dos; Barreto, Sandhi Maria

To describe the performance of a non-fluoroscopic fixed-flexion PA radiographic protocol with a new positioning device, developed for the assessment of knee osteoarthritis (OA) in Brazilian Longitudinal Study of Adult Health Musculoskeletal Study (ELSA-Brasil MSK). A test-retest design including 19 adults (38 knee images) was conducted. Feasibility of the radiographic protocol was assessed by image quality parameters and presence of radioanatomic alignment according to intermargin distance (IMD) values. Repeatability was assessed for IMD and joint space width (JSW) measured at three different locations. Approximately 90% of knee images presented excellent quality. Frequencies of nearly perfect radioanatomic alignment (IMD ≤1mm) ranged from 29% to 50%, and satisfactory alignment was found in up to 71% and 76% of the images (IMD ≤1.5mm and ≤1.7mm, respectively). Repeatability analyses yielded the following results: IMD [SD of mean difference=1.08; coefficient of variation (%CV)=54.68%; intraclass correlation coefficient (ICC) (95%CI)=0.59 (0.34-0.77)]; JSW [SD of mean difference=0.34-0.61; %CV=4.48%-9.80%; ICC (95%CI)=0.74 (0.55-0.85)-0.94 (0.87-0.97)]. Adequately reproducible measurements of IMD and JSW were found in 68% and 87% of the images, respectively. Despite the difficulty in achieving consistent radioanatomic alignment between subsequent radiographs in terms of IMD, the protocol produced highly repeatable JSW measurements when these were taken at midpoint and 10mm from the medial extremity of the medial tibial plateau. Therefore, measurements of JSW at these locations can be considered adequate for the assessment of knee OA in ELSA-Brasil MSK. Copyright © 2016. Published by Elsevier Editora Ltda.

Are reconstruction filters necessary?

NASA Astrophysics Data System (ADS)

Holst, Gerald C.

2006-05-01

Shannon's sampling theorem (also called the Shannon-Whittaker-Kotel'nikov theorem) was developed for the digitization and reconstruction of sinusoids. Strict adherence is required when frequency preservation is important. Three conditions must be met to satisfy the sampling theorem: (1) The signal must be band-limited, (2) the digitizer must sample the signal at an adequate rate, and (3) a low-pass reconstruction filter must be present. In an imaging system, the signal is band-limited by the optics. For most imaging systems, the signal is not adequately sampled resulting in aliasing. While the aliasing seems excessive mathematically, it does not significantly affect the perceived image. The human visual system detects intensity differences, spatial differences (shapes), and color differences. The eye is less sensitive to frequency effects and therefore sampling artifacts have become quite acceptable. Indeed, we love our television even though it is significantly undersampled. The reconstruction filter, although absolutely essential, is rarely discussed. It converts digital data (which we cannot see) into a viewable analog signal. There are several reconstruction filters: electronic low-pass filters, the display media (monitor, laser printer), and your eye. These are often used in combination to create a perceived continuous image. Each filter modifies the MTF in a unique manner. Therefore image quality and system performance depends upon the reconstruction filter(s) used. The selection depends upon the application.

Infrared imaging results of an excited planar jet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farrington, R.B.

1991-12-01

Planar jets are used for many applications including heating, cooling, and ventilation. Generally such a jet is designed to provide good mixing within an enclosure. In building applications, the jet provides both thermal comfort and adequate indoor air quality. Increased mixing rates may lead to lower short-circuiting of conditioned air, elimination of dead zones within the occupied zone, reduced energy costs, increased occupant comfort, and higher indoor air quality. This paper discusses using an infrared imaging system to show the effect of excitation of a jet on the spread angle and on the jet mixing efficiency. Infrared imaging captures amore » large number of data points in real time (over 50,000 data points per image) providing significant advantages over single-point measurements. We used a screen mesh with a time constant of approximately 0.3 seconds as a target for the infrared camera to detect temperature variations in the jet. The infrared images show increased jet spread due to excitation of the jet. Digital data reduction and analysis show change in jet isotherms and quantify the increased mixing caused by excitation. 17 refs., 20 figs.« less

Reduction of speckle noise from optical coherence tomography images using multi-frame weighted nuclear norm minimization method

NASA Astrophysics Data System (ADS)

Thapa, Damber; Raahemifar, Kaamran; Lakshminarayanan, Vasudevan

2015-12-01

In this paper, we propose a speckle noise reduction method for spectral-domain optical coherence tomography (SD-OCT) images called multi-frame weighted nuclear norm minimization (MWNNM). This method is a direct extension of weighted nuclear norm minimization (WNNM) in the multi-frame framework since an adequately denoised image could not be achieved with single-frame denoising methods. The MWNNM method exploits multiple B-scans collected from a small area of a SD-OCT volumetric image, and then denoises and averages them together to obtain a high signal-to-noise ratio B-scan. The results show that the image quality metrics obtained by denoising and averaging only five nearby B-scans with MWNNM method is considerably better than those of the average image obtained by registering and averaging 40 azimuthally repeated B-scans.

An investigation of automatic exposure control calibration for chest imaging with a computed radiography system.

PubMed

Moore, C S; Wood, T J; Avery, G; Balcam, S; Needler, L; Beavis, A W; Saunderson, J R

2014-05-07

The purpose of this study was to examine the use of three physical image quality metrics in the calibration of an automatic exposure control (AEC) device for chest radiography with a computed radiography (CR) imaging system. The metrics assessed were signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQm), all measured using a uniform chest phantom. Subsequent calibration curves were derived to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated chest images with correct detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated chest images contained clinically realistic projected anatomy and anatomical noise and were scored by experienced image evaluators. Constant DDI and CNR curves do not appear to provide optimized performance across the diagnostic energy range. Conversely, constant eNEQm and SNR do appear to provide optimized performance, with the latter being the preferred calibration metric given as it is easier to measure in practice. Medical physicists may use the SNR image quality metric described here when setting up and optimizing AEC devices for chest radiography CR systems with a degree of confidence that resulting clinical image quality will be adequate for the required clinical task. However, this must be done with close cooperation of expert image evaluators, to ensure appropriate levels of detector air kerma.

An investigation of automatic exposure control calibration for chest imaging with a computed radiography system

NASA Astrophysics Data System (ADS)

Moore, C. S.; Wood, T. J.; Avery, G.; Balcam, S.; Needler, L.; Beavis, A. W.; Saunderson, J. R.

2014-05-01

The purpose of this study was to examine the use of three physical image quality metrics in the calibration of an automatic exposure control (AEC) device for chest radiography with a computed radiography (CR) imaging system. The metrics assessed were signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQm), all measured using a uniform chest phantom. Subsequent calibration curves were derived to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated chest images with correct detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated chest images contained clinically realistic projected anatomy and anatomical noise and were scored by experienced image evaluators. Constant DDI and CNR curves do not appear to provide optimized performance across the diagnostic energy range. Conversely, constant eNEQm and SNR do appear to provide optimized performance, with the latter being the preferred calibration metric given as it is easier to measure in practice. Medical physicists may use the SNR image quality metric described here when setting up and optimizing AEC devices for chest radiography CR systems with a degree of confidence that resulting clinical image quality will be adequate for the required clinical task. However, this must be done with close cooperation of expert image evaluators, to ensure appropriate levels of detector air kerma.

Automatic quality assessment of apical four-chamber echocardiograms using deep convolutional neural networks

NASA Astrophysics Data System (ADS)

Abdi, Amir H.; Luong, Christina; Tsang, Teresa; Allan, Gregory; Nouranian, Saman; Jue, John; Hawley, Dale; Fleming, Sarah; Gin, Ken; Swift, Jody; Rohling, Robert; Abolmaesumi, Purang

2017-02-01

Echocardiography (echo) is the most common test for diagnosis and management of patients with cardiac condi- tions. While most medical imaging modalities benefit from a relatively automated procedure, this is not the case for echo and the quality of the final echo view depends on the competency and experience of the sonographer. It is not uncommon that the sonographer does not have adequate experience to adjust the transducer and acquire a high quality echo, which may further affect the clinical diagnosis. In this work, we aim to aid the operator during image acquisition by automatically assessing the quality of the echo and generating the Automatic Echo Score (AES). This quality assessment method is based on a deep convolutional neural network, trained in an end-to-end fashion on a large dataset of apical four-chamber (A4C) echo images. For this project, an expert car- diologist went through 2,904 A4C images obtained from independent studies and assessed their condition based on a 6-scale grading system. The scores assigned by the expert ranged from 0 to 5. The distribution of scores among the 6 levels were almost uniform. The network was then trained on 80% of the data (2,345 samples). The average absolute error of the trained model in calculating the AES was 0.8 +/- 0:72. The computation time of the GPU implementation of the neural network was estimated at 5 ms per frame, which is sufficient for real-time deployment.

Machine Vision-Based Measurement Systems for Fruit and Vegetable Quality Control in Postharvest.

PubMed

Blasco, José; Munera, Sandra; Aleixos, Nuria; Cubero, Sergio; Molto, Enrique

Individual items of any agricultural commodity are different from each other in terms of colour, shape or size. Furthermore, as they are living thing, they change their quality attributes over time, thereby making the development of accurate automatic inspection machines a challenging task. Machine vision-based systems and new optical technologies make it feasible to create non-destructive control and monitoring tools for quality assessment to ensure adequate accomplishment of food standards. Such systems are much faster than any manual non-destructive examination of fruit and vegetable quality, thus allowing the whole production to be inspected with objective and repeatable criteria. Moreover, current technology makes it possible to inspect the fruit in spectral ranges beyond the sensibility of the human eye, for instance in the ultraviolet and near-infrared regions. Machine vision-based applications require the use of multiple technologies and knowledge, ranging from those related to image acquisition (illumination, cameras, etc.) to the development of algorithms for spectral image analysis. Machine vision-based systems for inspecting fruit and vegetables are targeted towards different purposes, from in-line sorting into commercial categories to the detection of contaminants or the distribution of specific chemical compounds on the product's surface. This chapter summarises the current state of the art in these techniques, starting with systems based on colour images for the inspection of conventional colour, shape or external defects and then goes on to consider recent developments in spectral image analysis for internal quality assessment or contaminant detection.

Deep into the Brain: Artificial Intelligence in Stroke Imaging

PubMed Central

Lee, Eun-Jae; Kim, Yong-Hwan; Kim, Namkug; Kang, Dong-Wha

2017-01-01

Artificial intelligence (AI), a computer system aiming to mimic human intelligence, is gaining increasing interest and is being incorporated into many fields, including medicine. Stroke medicine is one such area of application of AI, for improving the accuracy of diagnosis and the quality of patient care. For stroke management, adequate analysis of stroke imaging is crucial. Recently, AI techniques have been applied to decipher the data from stroke imaging and have demonstrated some promising results. In the very near future, such AI techniques may play a pivotal role in determining the therapeutic methods and predicting the prognosis for stroke patients in an individualized manner. In this review, we offer a glimpse at the use of AI in stroke imaging, specifically focusing on its technical principles, clinical application, and future perspectives. PMID:29037014

A Bayesian Approach for Image Segmentation with Shape Priors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Hang; Yang, Qing; Parvin, Bahram

2008-06-20

Color and texture have been widely used in image segmentation; however, their performance is often hindered by scene ambiguities, overlapping objects, or missingparts. In this paper, we propose an interactive image segmentation approach with shape prior models within a Bayesian framework. Interactive features, through mouse strokes, reduce ambiguities, and the incorporation of shape priors enhances quality of the segmentation where color and/or texture are not solely adequate. The novelties of our approach are in (i) formulating the segmentation problem in a well-de?ned Bayesian framework with multiple shape priors, (ii) ef?ciently estimating parameters of the Bayesian model, and (iii) multi-object segmentationmore » through user-speci?ed priors. We demonstrate the effectiveness of our method on a set of natural and synthetic images.« less

Deep into the Brain: Artificial Intelligence in Stroke Imaging.

PubMed

Lee, Eun-Jae; Kim, Yong-Hwan; Kim, Namkug; Kang, Dong-Wha

2017-09-01

Artificial intelligence (AI), a computer system aiming to mimic human intelligence, is gaining increasing interest and is being incorporated into many fields, including medicine. Stroke medicine is one such area of application of AI, for improving the accuracy of diagnosis and the quality of patient care. For stroke management, adequate analysis of stroke imaging is crucial. Recently, AI techniques have been applied to decipher the data from stroke imaging and have demonstrated some promising results. In the very near future, such AI techniques may play a pivotal role in determining the therapeutic methods and predicting the prognosis for stroke patients in an individualized manner. In this review, we offer a glimpse at the use of AI in stroke imaging, specifically focusing on its technical principles, clinical application, and future perspectives.

Monitoring black-tailed prairie dog colonies with high-resolution satellite imagery

USGS Publications Warehouse

Sidle, John G.; Johnson, D.H.; Euliss, B.R.; Tooze, M.

2002-01-01

The United States Fish and Wildlife Service has determined that the black-tailed prairie dog (Cynomys ludovicianus) warrants listing as a threatened species under the Endangered Species Act. Central to any conservation planning for the black-tailed prairie dog is an appropriate detection and monitoring technique. Because coarse-resolution satellite imagery is not adequate to detect black-tailed prairie dog colonies, we examined the usefulness of recently available high-resolution (1-m) satellite imagery. In 6 purchased scenes of national grasslands, we were easily able to visually detect small and large colonies without using image-processing algorithms. The Ikonos (Space Imaging(tm)) satellite imagery was as adequate as large-scale aerial photography to delineate colonies. Based on the high quality of imagery, we discuss a possible monitoring program for black-tailed prairie dog colonies throughout the Great Plains, using the species' distribution in North Dakota as an example. Monitoring plots could be established and imagery acquired periodically to track the expansion and contraction of colonies.

Why Physics in Medicine?

PubMed

Samei, Ehsan; Grist, Thomas M

2018-05-18

Despite its crucial role in the development of new medical imaging technologies, in clinical practice, physics has primarily been involved in the technical evaluation of technologies. However, this narrow role is no longer adequate. New trajectories in medicine call for a stronger role for physics in the clinic. The movement toward evidence-based, quantitative, and value-based medicine requires physicists to play a more integral role in delivering innovative precision care through the intentional clinical application of physical sciences. There are three aspects of this clinical role: technology assessment based on metrics as they relate to expected clinical performance, optimized use of technologies for patient-centered clinical outcomes, and retrospective analysis of imaging operations to ensure attainment of expectations in terms of quality and variability. These tasks fuel the drive toward high-quality, consistent practice of medical imaging that is patient centered, evidence based, and safe. While this particular article focuses on imaging, this trajectory and paradigm is equally applicable to the multitudes of the applications of physics in medicine. Copyright © 2018 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Optimising μCT imaging of the middle and inner cat ear.

PubMed

Seifert, H; Röher, U; Staszyk, C; Angrisani, N; Dziuba, D; Meyer-Lindenberg, A

2012-04-01

This study's aim was to determine the optimal scan parameters for imaging the middle and inner ear of the cat with micro-computertomography (μCT). Besides, the study set out to assess whether adequate image quality can be obtained to use μCT in diagnostics and research on cat ears. For optimisation, μCT imaging of two cat skull preparations was performed using 36 different scanning protocols. The μCT-scans were evaluated by four experienced experts with regard to the image quality and detail detectability. By compiling a ranking of the results, the best possible scan parameters could be determined. From a third cat's skull, a μCT-scan, using these optimised scan parameters, and a comparative clinical CT-scan were acquired. Afterwards, histological specimens of the ears were produced which were compared to the μCT-images. The comparison shows that the osseous structures are depicted in detail. Although soft tissues cannot be differentiated, the osseous structures serve as valuable spatial orientation of relevant nerves and muscles. Clinical CT can depict many anatomical structures which can also be seen on μCT-images, but these appear a lot less sharp and also less detailed than with μCT. © 2011 Blackwell Verlag GmbH.

Comparison of Flexible Ureterorenoscope Quality of Vision: An In Vitro Study.

PubMed

Talso, Michele; Proietti, Silvia; Emiliani, Esteban; Gallioli, Andrea; Dragos, Laurian; Orosa, Andrea; Servian, Pol; Barreiro, Aaron; Giusti, Guido; Montanari, Emanuele; Somani, Bhaskar; Traxer, Olivier

2018-06-01

Flexible ureterorenoscopy (fURS) is one of the best solutions for treatment of renal calculi <2 cm and for upper urinary tract urothelial carcinoma conservative treatment. An adequate quality of vision is mandatory to help surgeon get better outcomes. No studies have been done, to our knowledge, about what fURS in the market has the best quality of vision. Seven different fURS were used to compare the image quality (Lithovue, Olympus V, Olympus V2, Storz Flex XC-in White Light and in Clara+Chroma mode-Wolf Cobra Vision, Olympus P6, and Storx Flex X2). Two standardized grids to evaluate contrast and image definition and three stones of different composition were filmed in four standardized different scenarios. These videos were shown to 103 subjects (51 urologists and 52 nonurologists) who had to evaluate them with a rating scale from 1 (very bad) to 5 (very good). No difference in terms of scores was observed for sex of the participants. Digital (D) ureterorenoscopes were rated better than fiber optics (FOs) ureterorenoscopes. Overall, Flex XC White Light and XC Clara+Chroma image quality resulted steadily better than other fURS (p < 0.0001). Olympus V generally provided a vision better than Lithovue. Cobra Vision and Olympus V2 had superimposable values that were significantly lower than Lithovue's ones. Olympus P6 and Storz X2 offered a low quality of vision compared to the others. In the medium simulating bleeding, Olympus V and V2 significantly improved their scores of 12% and 8.1%, contrary to rest of the ureterorenoscopes. D ureterorenoscopes have a better image quality than FO ones. The only disposable ureterorenoscope tested was comparable to the majority of other D ureterorenoscopes. The best image quality was provided by Storz D ureterorenoscopes, being Clara Chroma the favorite Spies Mode, according to literature.

Limiting CT radiation dose in children with craniosynostosis: phantom study using model-based iterative reconstruction.

PubMed

Kaasalainen, Touko; Palmu, Kirsi; Lampinen, Anniina; Reijonen, Vappu; Leikola, Junnu; Kivisaari, Riku; Kortesniemi, Mika

2015-09-01

Medical professionals need to exercise particular caution when developing CT scanning protocols for children who require multiple CT studies, such as those with craniosynostosis. To evaluate the utility of ultra-low-dose CT protocols with model-based iterative reconstruction techniques for craniosynostosis imaging. We scanned two pediatric anthropomorphic phantoms with a 64-slice CT scanner using different low-dose protocols for craniosynostosis. We measured organ doses in the head region with metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters. Numerical simulations served to estimate organ and effective doses. We objectively and subjectively evaluated the quality of images produced by adaptive statistical iterative reconstruction (ASiR) 30%, ASiR 50% and Veo (all by GE Healthcare, Waukesha, WI). Image noise and contrast were determined for different tissues. Mean organ dose with the newborn phantom was decreased up to 83% compared to the routine protocol when using ultra-low-dose scanning settings. Similarly, for the 5-year phantom the greatest radiation dose reduction was 88%. The numerical simulations supported the findings with MOSFET measurements. The image quality remained adequate with Veo reconstruction, even at the lowest dose level. Craniosynostosis CT with model-based iterative reconstruction could be performed with a 20-μSv effective dose, corresponding to the radiation exposure of plain skull radiography, without compromising required image quality.

Improving the quality of child anthropometry: Manual anthropometry in the Body Imaging for Nutritional Assessment Study (BINA).

PubMed

Conkle, Joel; Ramakrishnan, Usha; Flores-Ayala, Rafael; Suchdev, Parminder S; Martorell, Reynaldo

2017-01-01

Anthropometric data collected in clinics and surveys are often inaccurate and unreliable due to measurement error. The Body Imaging for Nutritional Assessment Study (BINA) evaluated the ability of 3D imaging to correctly measure stature, head circumference (HC) and arm circumference (MUAC) for children under five years of age. This paper describes the protocol for and the quality of manual anthropometric measurements in BINA, a study conducted in 2016-17 in Atlanta, USA. Quality was evaluated by examining digit preference, biological plausibility of z-scores, z-score standard deviations, and reliability. We calculated z-scores and analyzed plausibility based on the 2006 WHO Child Growth Standards (CGS). For reliability, we calculated intra- and inter-observer Technical Error of Measurement (TEM) and Intraclass Correlation Coefficient (ICC). We found low digit preference; 99.6% of z-scores were biologically plausible, with z-score standard deviations ranging from 0.92 to 1.07. Total TEM was 0.40 for stature, 0.28 for HC, and 0.25 for MUAC in centimeters. ICC ranged from 0.99 to 1.00. The quality of manual measurements in BINA was high and similar to that of the anthropometric data used to develop the WHO CGS. We attributed high quality to vigorous training, motivated and competent field staff, reduction of non-measurement error through the use of technology, and reduction of measurement error through adequate monitoring and supervision. Our anthropometry measurement protocol, which builds on and improves upon the protocol used for the WHO CGS, can be used to improve anthropometric data quality. The discussion illustrates the need to standardize anthropometric data quality assessment, and we conclude that BINA can provide a valuable evaluation of 3D imaging for child anthropometry because there is comparison to gold-standard, manual measurements.

An indicator device for monitoring of room illuminance level in the radiological image viewing environment.

PubMed

Azlan, C A; Ng, K H; Anandan, S; Nizam, M S

2006-09-01

Illuminance level in the softcopy image viewing room is a very important factor to optimize productivity in radiological diagnosis. In today's radiological environment, the illuminance measurements are normally done during the quality control procedure and performed annually. Although the room is equipped with dimmer switches, radiologists are not able to decide the level of illuminance according to the standards. The aim of this study is to develop a simple real-time illuminance detector system to assist the radiologists in deciding an adequate illuminance level during radiological image viewing. The system indicates illuminance in a very simple visual form by using light emitting diodes. By employing the device in the viewing room, illuminance level can be monitored and adjusted effectively.

Contrast enhanced imaging with a stationary digital breast tomosynthesis system

NASA Astrophysics Data System (ADS)

Puett, Connor; Calliste, Jabari; Wu, Gongting; Inscoe, Christina R.; Lee, Yueh Z.; Zhou, Otto; Lu, Jianping

2017-03-01

Digital breast tomosynthesis (DBT) captures some depth information and thereby improves the conspicuity of breast lesions, compared to standard mammography. Using contrast during DBT may also help distinguish malignant from benign sites. However, adequate visualization of the low iodine signal requires a subtraction step to remove background signal and increase lesion contrast. Additionally, attention to factors that limit contrast, including scatter, noise, and artifact, are important during the image acquisition and post-acquisition processing steps. Stationary DBT (sDBT) is an emerging technology that offers a higher spatial and temporal resolution than conventional DBT. This phantom-based study explored contrast-enhanced sDBT (CE sDBT) across a range of clinically-appropriate iodine concentrations, lesion sizes, and breast thicknesses. The protocol included an effective scatter correction method and an iterative reconstruction technique that is unique to the sDBT system. The study demonstrated the ability of this CE sDBT system to collect projection images adequate for both temporal subtraction (TS) and dual-energy subtraction (DES). Additionally, the reconstruction approach preserved the improved contrast-to-noise ratio (CNR) achieved in the subtraction step. Finally, scatter correction increased the iodine signal and CNR of iodine-containing regions in projection views and reconstructed image slices during both TS and DES. These findings support the ongoing study of sDBT as a potentially useful tool for contrast-enhanced breast imaging and also highlight the significant effect that scatter has on image quality during DBT.

Dose, image quality and spine modeling assessment of biplanar EOS micro-dose radiographs for the follow-up of in-brace adolescent idiopathic scoliosis patients.

PubMed

Morel, Baptiste; Moueddeb, Sonia; Blondiaux, Eleonore; Richard, Stephen; Bachy, Manon; Vialle, Raphael; Ducou Le Pointe, Hubert

2018-05-01

The aim of this study was to compare the radiation dose, image quality and 3D spine parameter measurements of EOS low-dose and micro-dose protocols for in-brace adolescent idiopathic scoliosis (AIS) patients. We prospectively included 25 consecutive patients (20 females, 5 males) followed for AIS and undergoing brace treatment. The mean age was 12 years (SD 2 years, range 8-15 years). For each patient, in-brace biplanar EOS radiographs were acquired in a standing position using both the conventional low-dose and micro-dose protocols. Dose area product (DAP) was systematically recorded. Diagnostic image quality was qualitatively assessed by two radiologists for visibility of anatomical structures. The reliability of 3D spine modeling between two operators was quantitatively evaluated for the most clinically relevant 3D radiological parameters using intraclass correlation coefficient (ICC). The mean DAP for the posteroanterior and lateral acquisitions was 300 ± 134 and 433 ± 181 mGy cm 2 for the low-dose radiographs, and 41 ± 19 and 81 ± 39 mGy cm 2 for micro-dose radiographs. Image quality was lower with the micro-dose protocol. The agreement was "good" to "very good" for all measured clinical parameters when comparing the low-dose and micro-dose protocols (ICC > 0.73). The micro-dose protocol substantially reduced the delivered dose (by a factor of 5-7 compared to the low-dose protocol) in braced children with AIS. Although image quality was reduced, the micro-dose protocol proved to be adapted to radiological follow-up, with adequate image quality and reliable clinical measurements. These slides can be retrieved under Electronic Supplementary Material.

Nonenhanced ECG-gated quiescent-interval single shot MRA: image quality and stenosis assessment at 3 tesla compared with contrast-enhanced MRA and digital subtraction angiography.

PubMed

Hansmann, Jan; Morelli, John N; Michaely, Henrik J; Riester, Thomas; Budjan, Johannes; Schoenberg, Stefan O; Attenberger, Ulrike I

2014-06-01

To evaluate the diagnostic accuracy of a nonenhanced electrocardiograph-gated quiescent-interval single shot MR-angiography (QISS-MRA) at 3 Tesla with contrast-enhanced MRA (CE-MRA) and digital subtraction angiography (DSA) serving as reference standard. Following institutional review board approval, 16 consecutive patients with peripheral arterial disease underwent a combined peripheral MRA protocol consisting of a large field-of-view QISS-MRA, continuous table movement MRA, and an additional time-resolved MRA of the calves. DSA correlation was available in eight patients. Image quality and degree of stenosis was assessed. Sensitivity and specificity of QISS-MRA was evaluated with CE-MRA and DSA serving as the standards of reference and compared using the Fisher exact test. With the exception of the calf station, image quality with QISS-MRA was rated statistically significantly less than that of CE-MRA (P < 0.05, P = 0.17, and P = 0.6, respectively). A greater percentage of segments were not accessible with QISS-MRA (19.5-20.1%) in comparison to CE-MRA (10.9%). Relative to DSA, sensitivity for QISS-MRA was high (100% versus 91.2% for CE-MRA, P = 0.24) in the evaluated segments; however, specificity (76.5%) was substantially less than that of CE-MRA (94.6%, P = 0.003). Overall image quality and specificity of QISS-MRA at 3T are diminished relative to CE-MRA. However, when image quality is adequate, QISS-MRA has high sensitivity and, thus, has potential use in patients with contraindications to gadolinium. Copyright © 2013 Wiley Periodicals, Inc.

LANDSAT-4 image data quality analysis for energy related applications. [nuclear power plant sites

NASA Technical Reports Server (NTRS)

Wukelic, G. E. (Principal Investigator)

1983-01-01

No useable LANDSAT 4 TM data were obtained for the Hanford site in the Columbia Plateau region, but TM simulator data for a Virginia Electric Company nuclear power plant was used to test image processing algorithms. Principal component analyses of this data set clearly indicated that thermal plumes in surface waters used for reactor cooling would be discrenible. Image processing and analysis programs were successfully testing using the 7 band Arkansas test scene and preliminary analysis of TM data for the Savanah River Plant shows that current interactive, image enhancement, analysis and integration techniques can be effectively used for LANDSAT 4 data. Thermal band data appear adequate for gross estimates of thermal changes occurring near operating nuclear facilities especially in surface water bodies being used for reactor cooling purposes. Additional image processing software was written and tested which provides for more rapid and effective analysis of the 7 band TM data.

Purgative bowel cleansing combined with simethicone improves capsule endoscopy imaging.

PubMed

Wei, Wei; Ge, Zhi-Zheng; Lu, Hong; Gao, Yun-Jie; Hu, Yun-Biao; Xiao, Shu-Dong

2008-01-01

To evaluate the effects of the various methods of small bowel preparation on the quality of visualization of the small bowel and the gastrointestinal transit time of capsule endoscopy (CE). Ninety patients referred for CE were prospectively randomized to three equal groups according to the preparation used: (a) a control group, in which patients were requested to drink 1 L of clear liquids only, 12 h before the examination; (b) a purgative group, in which patients were requested to ingest 1 L of a polyethylene glycol (PEG)/electrolyte solution only, 12 h before the examination; or (c) a purgative combined with simethicone group (P-S group), in which patients were requested to ingest 1 L of PEG, 12 h before the examination, and 300 mg of simethicone, 20 min before the examination. Effects of the different bowel preparations on the gastric transit time (GTT), small bowel transit time (SBTT), examination completion rate, quality of images of the entire small intestine, and cleansing of the proximal small bowel and distal ileum were evaluated. The number of patients with "adequate" cleansing of the entire small intestine was 17 in the P-S group, 12 in the purgative group, and seven in the control group (P= 0.002). The P-S group had significantly better image quality than the control group (P= 0.001). The P-S group had significantly better image quality for the proximal small bowel (segment A [Seg A]) than the control group (P= 0.0001). Both the P-S group (P= 0.0001) and the purgative group (P= 0.0002) had significantly better image quality for the distal ileum (segment B [Seg B]) than the control group; the P-S group had significantly better image quality than the purgative group as well (P= 0.0121). Gastrointestinal transit time was not different among the three groups, nor was the examination completion rate. Purgative bowel cleansing combined with simethicone before CE improved the quality of imaging of the entire small bowel as well as the visualization of the mucosa in the proximal and distal small intestine.

Motion-Blurred Particle Image Restoration for On-Line Wear Monitoring

PubMed Central

Peng, Yeping; Wu, Tonghai; Wang, Shuo; Kwok, Ngaiming; Peng, Zhongxiao

2015-01-01

On-line images of wear debris contain important information for real-time condition monitoring, and a dynamic imaging technique can eliminate particle overlaps commonly found in static images, for instance, acquired using ferrography. However, dynamic wear debris images captured in a running machine are unavoidably blurred because the particles in lubricant are in motion. Hence, it is difficult to acquire reliable images of wear debris with an adequate resolution for particle feature extraction. In order to obtain sharp wear particle images, an image processing approach is proposed. Blurred particles were firstly separated from the static background by utilizing a background subtraction method. Second, the point spread function was estimated using power cepstrum to determine the blur direction and length. Then, the Wiener filter algorithm was adopted to perform image restoration to improve the image quality. Finally, experiments were conducted with a large number of dynamic particle images to validate the effectiveness of the proposed method and the performance of the approach was also evaluated. This study provides a new practical approach to acquire clear images for on-line wear monitoring. PMID:25856328

Magnetic resonance imaging evaluation of adjacent segments after cervical disc arthroplasty: magnet strength and its effect on image quality. Clinical article.

PubMed

Antosh, Ivan J; DeVine, John G; Carpenter, Clyde T; Woebkenberg, Brian J; Yoest, Stephen M

2010-12-01

Disc arthroplasty is an alternative to fusion following anterior discectomy when treating either cervical radiculopathy or myelopathy. Its theoretical benefits include preservation of the motion segment and the potential prevention of adjacent-segment degeneration. There is a paucity of data regarding the ability to use MR imaging to evaluate the adjacent segments. The purpose of this study was for the authors to introduce open MR imaging as an alternative method in imaging adjacent segments following cervical disc arthroplasty using a Co-Cr implant and to report their preliminary results using this technique. Postoperative cervical MR images were obtained in the first 16 patients in whom the porous coated motion (PCM-V) cervical arthroplasty system was used to treat a single level between C-3 and C-7. Imaging was performed in all 16 patients with a closed 1.5-T unit, and in the final 6 patients it was also performed with an open 0.2-T unit. All images were evaluated by an independent radiologist observer for the ability to visualize the superior endplate, disc space, and inferior endplate at the superior and inferior adjacent levels. Utilizing the 1.5-T magnet to assess the superior adjacent level, the superior endplate, disc space, and inferior endplate could each be visualized less than 50% of the time on sagittal T1- and sagittal and axial T2-weighted images. Similarly, the inferior adjacent level structures were adequately visualized less than 50% of the time, with the exception of slightly improved visualization of the inferior endplate on T1-weighted images (56%). Axial images allowed worse visualization than sagittal images at both the superior and inferior adjacent levels. Utilizing the 0.2-T magnet to assess the superior and inferior adjacent levels, the superior endplate, disc space, and inferior endplate were adequately visualized in 100% of images. Based on the results of this case series, it appears that the strength of the magnet affects the artifact from the Co-Cr endplates. The open 0.2-T MR imaging unit reduces artifact at adjacent levels after cervical disc arthroplasty without a significant reduction in the image quality. Magnetic resonance imaging can be used to evaluate the adjacent segments after disc arthroplasty if magnet strength is addressed, providing another means to assess the long-term efficacy of this novel treatment.

Reduction of the estimated radiation dose and associated patient risk with prospective ECG-gated 256-slice CT coronary angiography

NASA Astrophysics Data System (ADS)

Efstathopoulos, E. P.; Kelekis, N. L.; Pantos, I.; Brountzos, E.; Argentos, S.; Grebáč, J.; Ziaka, D.; Katritsis, D. G.; Seimenis, I.

2009-09-01

Computed tomography (CT) coronary angiography has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but high radiation doses have been reported. Prospective ECG-gating using a 'step-and-shoot' axial scanning protocol has been shown to reduce radiation exposure effectively while maintaining diagnostic accuracy. 256-slice scanners with 80 mm detector coverage have been currently introduced into practice, but their impact on radiation exposure has not been adequately studied. The aim of this study was to assess radiation doses associated with CT coronary angiography using a 256-slice CT scanner. Radiation doses were estimated for 25 patients scanned with either prospective or retrospective ECG-gating. Image quality was assessed objectively in terms of mean CT attenuation at selected regions of interest on axial coronary images and subjectively by coronary segment quality scoring. It was found that radiation doses associated with prospective ECG-gating were significantly lower than retrospective ECG-gating (3.2 ± 0.6 mSv versus 13.4 ± 2.7 mSv). Consequently, the radiogenic fatal cancer risk for the patient is much lower with prospective gating (0.0176% versus 0.0737%). No statistically significant differences in image quality were observed between the two scanning protocols for both objective and subjective quality assessments. Therefore, prospective ECG-gating using a 'step-and-shoot' protocol that covers the cardiac anatomy in two axial acquisitions effectively reduces radiation doses in 256-slice CT coronary angiography without compromising image quality.

The level of detail required in a deformable phantom to accurately perform quality assurance of deformable image registration

NASA Astrophysics Data System (ADS)

Saenz, Daniel L.; Kim, Hojin; Chen, Josephine; Stathakis, Sotirios; Kirby, Neil

2016-09-01

The primary purpose of the study was to determine how detailed deformable image registration (DIR) phantoms need to adequately simulate human anatomy and accurately assess the quality of DIR algorithms. In particular, how many distinct tissues are required in a phantom to simulate complex human anatomy? Pelvis and head-and-neck patient CT images were used for this study as virtual phantoms. Two data sets from each site were analyzed. The virtual phantoms were warped to create two pairs consisting of undeformed and deformed images. Otsu’s method was employed to create additional segmented image pairs of n distinct soft tissue CT number ranges (fat, muscle, etc). A realistic noise image was added to each image. Deformations were applied in MIM Software (MIM) and Velocity deformable multi-pass (DMP) and compared with the known warping. Images with more simulated tissue levels exhibit more contrast, enabling more accurate results. Deformation error (magnitude of the vector difference between known and predicted deformation) was used as a metric to evaluate how many CT number gray levels are needed for a phantom to serve as a realistic patient proxy. Stabilization of the mean deformation error was reached by three soft tissue levels for Velocity DMP and MIM, though MIM exhibited a persisting difference in accuracy between the discrete images and the unprocessed image pair. A minimum detail of three levels allows a realistic patient proxy for use with Velocity and MIM deformation algorithms.

Application of off-line image processing for optimization in chest computed radiography using a low cost system.

PubMed

Muhogora, Wilbroad E; Msaki, Peter; Padovani, Renato

2015-03-08

 The objective of this study was to improve the visibility of anatomical details by applying off-line postimage processing in chest computed radiography (CR). Four spatial domain-based external image processing techniques were developed by using MATLAB software version 7.0.0.19920 (R14) and image processing tools. The developed techniques were implemented to sample images and their visual appearances confirmed by two consultant radiologists to be clinically adequate. The techniques were then applied to 200 chest clinical images and randomized with other 100 images previously processed online. These 300 images were presented to three experienced radiologists for image quality assessment using standard quality criteria. The mean and ranges of the average scores for three radiologists were characterized for each of the developed technique and imaging system. The Mann-Whitney U-test was used to test the difference of details visibility between the images processed using each of the developed techniques and the corresponding images processed using default algorithms. The results show that the visibility of anatomical features improved significantly (0.005 ≤ p ≤ 0.02) with combinations of intensity values adjustment and/or spatial linear filtering techniques for images acquired using 60 ≤ kVp ≤ 70. However, there was no improvement for images acquired using 102 ≤ kVp ≤ 107 (0.127 ≤ p ≤ 0.48). In conclusion, the use of external image processing for optimization can be effective in chest CR, but should be implemented in consultations with the radiologists.

Application of off‐line image processing for optimization in chest computed radiography using a low cost system

PubMed Central

Msaki, Peter; Padovani, Renato

2015-01-01

The objective of this study was to improve the visibility of anatomical details by applying off‐line postimage processing in chest computed radiography (CR). Four spatial domain‐based external image processing techniques were developed by using MATLAB software version 7.0.0.19920 (R14) and image processing tools. The developed techniques were implemented to sample images and their visual appearances confirmed by two consultant radiologists to be clinically adequate. The techniques were then applied to 200 chest clinical images and randomized with other 100 images previously processed online. These 300 images were presented to three experienced radiologists for image quality assessment using standard quality criteria. The mean and ranges of the average scores for three radiologists were characterized for each of the developed technique and imaging system. The Mann‐Whitney U‐test was used to test the difference of details visibility between the images processed using each of the developed techniques and the corresponding images processed using default algorithms. The results show that the visibility of anatomical features improved significantly (0.005≤p≤0.02) with combinations of intensity values adjustment and/or spatial linear filtering techniques for images acquired using 60≤kVp≤70. However, there was no improvement for images acquired using 102≤kVp≤107 (0.127≤p≤0.48). In conclusion, the use of external image processing for optimization can be effective in chest CR, but should be implemented in consultations with the radiologists. PACS number: 87.59.−e, 87.59.−B, 87.59.−bd PMID:26103165

Patient-specific optimisation of administered activity and acquisition times for 18F-FDG PET imaging.

PubMed

Wickham, Fred; McMeekin, Helena; Burniston, Maria; McCool, Daniel; Pencharz, Deborah; Skillen, Annah; Wagner, Thomas

2017-12-01

The purpose of this study is to identify a method for optimising the administered activity and acquisition time for 18 F-FDG PET imaging, yielding images of consistent quality for patients with varying body sizes and compositions, while limiting radiation doses to patients and staff. Patients referred for FDG scans had bioimpedance measurements. They were injected with 3 MBq/kg of 18 F up to 370 MBq and scanned on a Siemens Biograph mCT at 3 or 4 min per bed position. Data were rebinned to simulate 2- and 1-min acquisitions. Subjective assessments of image quality made by an experienced physician were compared with objective measurements based on signal-to-noise ratio and noise equivalent counts (NEC). A target objective measure of image quality was identified. The activity and acquisition time required to achieve this were calculated for each subject. Multiple regression analysis was used to identify expressions for the activity and acquisition time required in terms of easily measurable patient characteristics. One hundred and eleven patients were recruited, and subjective and objective assessments of image quality were compared for 321 full and reduced time scans. NEC-per-metre was identified as the objective measure which best correlated with the subjective assessment (Spearman rank correlation coefficient 0.77) and the best discriminator for images with a subjective assessment of "definitely adequate" (area under the ROC curve 0.94). A target of 37 Mcount/m was identified. Expressions were identified in terms of patient sex, height and weight for the activity and acquisition time required to achieve this target. Including measurements of body composition in these expressions was not useful. Using these expressions would reduce the mean activity administered to this patient group by 66 MBq compared to the current protocol. Expressions have been identified for the activity and acquisition times required to achieve consistent image quality in FDG imaging with reduced patient and staff doses. These expressions might need to be adapted for other systems and reconstruction protocols.

Telepathology in Sweden. A national study including all histopathology and cytology laboratories.

PubMed

Busch, C

1992-12-01

Quality improvement and standardization of diagnosis in histopathology and cytology are important for the future of the discipline. Nominal scale diagnoses dominate the practice and their standardization depends on relevant and reproducibly identifiable criteria as well as on communication of these among pathologists. Telepathology, i.e. the transmission of adequately detailed colour images of microscopic fields over the telephone network is now a realistic possibility. All 30 laboratories for histopathology and cytology in Sweden will have access to Telepathology work stations for at least 8 weeks each during 1992-1993. Two centers will have permanent stations from September 1992. The images will be transmitted over the ISDN network, allowing a compressed image to appear instantaneously. This image is then gradually and imperceptibly decompressed during 15-60 seconds, the time depending on the complexity of the image. A program for consultation and quality testing is being set up, which will be evaluated during 1993. Based on a recognition of the conditions for diagnosis in pathology and cytology indicated above, the Swedish Society of Pathology has initiated a project called "Telepathology in Sweden". It is a joint effort with active participation by Swedish Telecom and the Swedish Planning and Rationalization Institute for the Health and Social Services, Stockholm as well as by Innovativ Vision AB, Linköping, a company providing hard- and software for image analysis, image banks and communication.

A technique of experimental and numerical analysis of influence of defects in the intraocular lens on the retinal image quality

NASA Astrophysics Data System (ADS)

Geniusz, Malwina; ZajÄ c, Marek

2016-09-01

Intraocular lens (IOL) is an artificial lens implanted into the eye in order to restore correct vision after the removal of natural lens cloudy due to cataract. The IOL prolonged stay in the eyeball causes the creation of different changes on the surface and inside the implant mainly in form of small-size local defects such as vacuoles and calcium deposites. Their presence worsens the imaging properties of the eye mainly due to occurence of scattered light thus deteriorating the vision quality of patients after cataract surgery. It is very difficult to study influence the effects of these changes on image quality in real patients. To avoid these difficulties two other possibilities were chosen: the analysis of the image obtained in an optomechanical eye model with artificially aged IOL as well as numerical calculation of the image characteristics while the eye lens is burdened with adequately modeled defects. In experiments the optomechanical model of an eye consisting of a glass "cornea", chamber filled with liquid where the IOL under investigation was inserted and a high resulution CCC detector serving as a "retina" was used. The Modulation Transfer Function (MTF) of such "eye" was evaluated on the basis of image of an edge. Experiments show that there is significant connection between ageing defects and decrease in MTF parameters. Numerical part was performed with a computer programme for optical imaging analysis (OpticStudio Professional, Zemax Professional from Radiant Zemax, LLC). On the basis of Atchison eye model with lens burdened with defects Modulation Transfer Functio was calculated. Particular parameters of defects used in a numerical model were based on own measurements. Numerical simulation also show significant connection between ageing defects and decrease of MTF parameters. With this technique the influence of types, density and distribution of local defect in the IOL on the retinal image quality can be evaluated quickly without the need of performing very difficult and even dangereous experiments on real human patients.

Clinical performance of a free-breathing spatiotemporally accelerated 3-D time-resolved contrast-enhanced pediatric abdominal MR angiography.

PubMed

Zhang, Tao; Yousaf, Ufra; Hsiao, Albert; Cheng, Joseph Y; Alley, Marcus T; Lustig, Michael; Pauly, John M; Vasanawala, Shreyas S

2015-10-01

Pediatric contrast-enhanced MR angiography is often limited by respiration, other patient motion and compromised spatiotemporal resolution. To determine the reliability of a free-breathing spatiotemporally accelerated 3-D time-resolved contrast-enhanced MR angiography method for depicting abdominal arterial anatomy in young children. With IRB approval and informed consent, we retrospectively identified 27 consecutive children (16 males and 11 females; mean age: 3.8 years, range: 14 days to 8.4 years) referred for contrast-enhanced MR angiography at our institution, who had undergone free-breathing spatiotemporally accelerated time-resolved contrast-enhanced MR angiography studies. A radio-frequency-spoiled gradient echo sequence with Cartesian variable density k-space sampling and radial view ordering, intrinsic motion navigation and intermittent fat suppression was developed. Images were reconstructed with soft-gated parallel imaging locally low-rank method to achieve both motion correction and high spatiotemporal resolution. Quality of delineation of 13 abdominal arteries in the reconstructed images was assessed independently by two radiologists on a five-point scale. Ninety-five percent confidence intervals of the proportion of diagnostically adequate cases were calculated. Interobserver agreements were also analyzed. Eleven out of 13 arteries achieved acceptable image quality (mean score range: 3.9-5.0) for both readers. Fair to substantial interobserver agreement was reached on nine arteries. Free-breathing spatiotemporally accelerated 3-D time-resolved contrast-enhanced MR angiography frequently yields diagnostic image quality for most abdominal arteries in young children.

Spectral optical coherence tomography: a novel technique for cornea imaging.

PubMed

Kaluzny, Bartłomiej J; Kaluzy, Bartłomiej J; Kałuzny, Jakub J; Szkulmowska, Anna; Gorczyńska, Iwona; Szkulmowski, Maciej; Bajraszewski, Tomasz; Wojtkowski, Maciej; Targowski, Piotr

2006-09-01

Spectral optical coherence tomography (SOCT) is a new, noninvasive, noncontact, high-resolution technique that provides cross-sectional images of the objects that weakly absorb and scatter light. SOCT, because of very short acquisition time and high sensitivity, is capable of providing tomograms of substantially better quality than the conventional OCT. The aim of this paper is to show the application of the SOCT to cross-sectional imaging of the cornea and its pathologies. Eleven eyes with different corneal pathologies were examined with a slit lamp and the use of a prototype SOCT instrument constructed in the Institute of Physics, Nicolaus Copernicus University, Toruń, Poland. Our SOCT system provides high-resolution (4 microm axial, 10 microm transversal) tomograms composed of 3000-5000 A-scans with an acquisition time of 120-200 ms. The quality of the images is adequate for detailed cross-sectional evaluation of various corneal pathologies. Objective assessment of the localization, size, shape, and light-scattering properties of the changed tissue is possible. Corneal and epithelial thickness and the depth and width of lesions can be estimated. SOCT technique allows acquiring clinically valuable cross-sectional optical biopsy of the cornea and its pathologies.

PET motion correction in context of integrated PET/MR: Current techniques, limitations, and future projections.

PubMed

Gillman, Ashley; Smith, Jye; Thomas, Paul; Rose, Stephen; Dowson, Nicholas

2017-12-01

Patient motion is an important consideration in modern PET image reconstruction. Advances in PET technology mean motion has an increasingly important influence on resulting image quality. Motion-induced artifacts can have adverse effects on clinical outcomes, including missed diagnoses and oversized radiotherapy treatment volumes. This review aims to summarize the wide variety of motion correction techniques available in PET and combined PET/CT and PET/MR, with a focus on the latter. A general framework for the motion correction of PET images is presented, consisting of acquisition, modeling, and correction stages. Methods for measuring, modeling, and correcting motion and associated artifacts, both in literature and commercially available, are presented, and their relative merits are contrasted. Identified limitations of current methods include modeling of aperiodic and/or unpredictable motion, attaining adequate temporal resolution for motion correction in dynamic kinetic modeling acquisitions, and maintaining availability of the MR in PET/MR scans for diagnostic acquisitions. Finally, avenues for future investigation are discussed, with a focus on improvements that could improve PET image quality, and that are practical in the clinical environment. © 2017 American Association of Physicists in Medicine.

Accuracy, image quality, and radiation dose of prospectively ECG-triggered high-pitch dual-source CT angiography in infants and children with complex coarctation of the aorta.

PubMed

Xu, Jian; Zhao, Hongliang; Wang, Xiaoying; Bai, Yuxiang; Liu, Liwen; Liu, Ying; Wei, Mengqi; Li, Jian; Zheng, Minwen

2014-10-01

To evaluate the diagnostic accuracy, image quality, and radiation dose of prospective electrocardiogram (ECG)-triggered high-pitch dual-source computed tomography (DSCT) in infants and young children with complex coarctation of the aorta (CoA). Forty pediatric patients aged < 4 years with suspected CoA underwent prospective ECG-triggered high-pitch DSCT angiography and transthoracic echocardiography (TTE). Surgery and/or conventional cardiac angiography (CCA) were performed in all patients. The diagnostic accuracy of DSCT angiography and TTE was compared to the surgical and/or CCA findings. The causes of misdiagnosis and miss were analyzed, and the advantages and limitation of both imaging modalities were evaluated. Image quality of DSCT was evaluated, and effective radiation dose was calculated. The sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy of DSCT in evaluation of complex CoA were 92.37%, 98.51%, 97.32%, 93.57%, and 96.25%, respectively. There was a significant difference in the accuracy between DSCT and TTE (χ² = 9.9, P＜.05). For a total of 80 extracardiac anomalies, the sensitivity (98.8%, 79/80) of DSCT was greater than that of TTE (62.5%; 50 of 80). On the contrary, for 38 cardiac anomalies, the sensitivity (78.9%, 30 of 38) of DSCT was lesser than that of TTE (100%; 38 of 38). The mean score of image quality was 4.27 ± 0.73. The mean effective radiation dose was 0.20 ± 0.09 mSv. Prospective ECG-triggered high-pitch DSCT may be a clinical feasible modality in the evaluation of pediatric patients with complex CoA, providing adequate image quality, high diagnostic accuracy, and low radiation dose. Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.

Performance evaluation of the Trans-PET® BioCaliburn® LH system: a large FOV small-animal PET system

NASA Astrophysics Data System (ADS)

Wang, Luyao; Zhu, Jun; Liang, Xiao; Niu, Ming; Wu, Xiaoke; Kao, Chien-Min; Kim, Heejong; Xie, Qingguo

2015-01-01

The Trans-PET® BioCaliburn® LH is a commercial positron emission tomography (PET) system for animal imaging. The system offers a large transaxial field-of-view (FOV) of 13.0 cm to allow imaging of multiple rodents or larger animals. This paper evaluates and reports the performance characteristics of this system. Methods: in this paper, the system was evaluated for its spatial resolutions, sensitivity, scatter fraction, count rate performance and image quality in accordance with the National Electrical Manufacturers Association (NEMA) NU-4 2008 specification with modifications. Phantoms and animals not specified in the NEMA specification were also scanned to provide further demonstration of its imaging capability. Results: the spatial resolution is 1.0 mm at the center. When using a 350-650 keV energy window and a 5 ns coincidence time window, the sensitivity at the center is 2.04%. The noise equivalent count-rate curve reaches a peak value of 62 kcps at 28 MBq for the mouse-sized phantom and a peak value of 25 kcps at 31 MBq for the rat-sized phantom. The scatter fractions are 8.4% and 17.7% for the mouse- and rat-sized phantoms, respectively. The uniformity and recovery coefficients measured by using the NEMA image-quality phantom both indicate good imaging performance, even though the reconstruction algorithm provided by the vendor does not implement all desired corrections. The Derenzo-phantom images show that the system can resolve 1.0 mm diameter rods. Animal studies demonstrate the capabilities of the system in dynamic imaging and to image multiple rodents. Conclusion: the Trans-PET® BioCaliburn® LH system offers high spatial resolution, a large transaixal FOV and adequate sensitivity. It produces animal images of good quality and supports dynamic imaging. The system is an attractive imaging technology for preclinical research.

Computer program CDCID: an automated quality control program using CDC update

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singer, G.L.; Aguilar, F.

1984-04-01

A computer program, CDCID, has been developed in coordination with a quality control program to provide a highly automated method of documenting changes to computer codes at EG and G Idaho, Inc. The method uses the standard CDC UPDATE program in such a manner that updates and their associated documentation are easily made and retrieved in various formats. The method allows each card image of a source program to point to the document which describes it, who created the card, and when it was created. The method described is applicable to the quality control of computer programs in general. Themore » computer program described is executable only on CDC computing systems, but the program could be modified and applied to any computing system with an adequate updating program.« less

The subxiphoid view cannot replace the apical view for transthoracic echocardiographic assessment of hemodynamic status

PubMed Central

2013-01-01

Introduction This prospective study aimed to assess whether use of the subxiphoid acoustic window in transthoracic echocardiography (TTE) can be an accurate alternative in the absence of an apical view to assess hemodynamic parameters. Methods This prospective study took place in a teaching hospital medical ICU. Over a 4-month period, TTE was performed in patients admitted for more than 24 hours. Two operators rated the quality of parasternal, apical, and subxiphoid acoustic windows as Excellent, Good, Acceptable, Poor, or No image. In the subpopulation presenting adequate (rated as acceptable or higher) apical and subxiphoid views, we compared the left ventricular ejection fraction (LVEF), the ratio between right and left ventricular end-diastolic areas (RVEDA/LVEDA), the ratio between early and late mitral inflow on pulsed Doppler (E/A ratio), the aortic velocity time integral (Ao VTI), and the ratio between early mitral inflow and displacement of the mitral annulus on tissue Doppler imaging (E/Ea ratio). Results An adequate apical view was obtained in 80%, and an adequate subxiphoid view was obtained in 63% of the 107 patients included. Only 5% of patients presented an adequate subxiphoid view without an adequate apical view. In the subpopulation of patients with adequate apical and subxiphoid windows (n = 65), LVEF, E/A, and RVEDA/LVEDA were comparable on both views, and were strongly correlated (r > 0.80) with acceptable biases and precision. However, the Ao VTI and the E/Ea ratio were lower on the subxiphoid view than on the apical view (18 ± 5 versus 16 ± 5 cm and 9.6 ± 4.6 versus 7.6 ± 4 cm, respectively, P = 0.001 for both). Conclusions An adequate TTE subxiphoid window was obtained in fewer than two thirds of ICU patients. In addition to the classic indication for the subxiphoid window to study the vena cava and pericardium, this view can be used to study right and left ventricular morphology and function, but does not provide accurate hemodynamic Doppler information. ICU echocardiographers should therefore record both apical and subxiphoid views to assess comprehensively the cardiac function and hemodynamic status. PMID:24004960

Abdominal CT with model-based iterative reconstruction (MBIR): initial results of a prospective trial comparing ultralow-dose with standard-dose imaging.

PubMed

Pickhardt, Perry J; Lubner, Meghan G; Kim, David H; Tang, Jie; Ruma, Julie A; del Rio, Alejandro Muñoz; Chen, Guang-Hong

2012-12-01

The purpose of this study was to report preliminary results of an ongoing prospective trial of ultralow-dose abdominal MDCT. Imaging with standard-dose contrast-enhanced (n = 21) and unenhanced (n = 24) clinical abdominal MDCT protocols was immediately followed by ultralow-dose imaging of a matched series of 45 consecutively registered adults (mean age, 57.9 years; mean body mass index, 28.5). The ultralow-dose images were reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), and model-based iterative reconstruction (MBIR). Standard-dose series were reconstructed with FBP (reference standard). Image noise was measured at multiple predefined sites. Two blinded abdominal radiologists interpreted randomly presented ultralow-dose images for multilevel subjective image quality (5-point scale) and depiction of organ-based focal lesions. Mean dose reduction relative to the standard series was 74% (median, 78%; range, 57-88%; mean effective dose, 1.90 mSv). Mean multiorgan image noise for low-dose MBIR was 14.7 ± 2.6 HU, significantly lower than standard-dose FBP (28.9 ± 9.9 HU), low-dose FBP (59.2 ± 23.3 HU), and ASIR (45.6 ± 14.1 HU) (p < 0.001). The mean subjective image quality score for low-dose MBIR (3.0 ± 0.5) was significantly higher than for low-dose FBP (1.6 ± 0.7) and ASIR (1.8 ± 0.7) (p < 0.001). Readers identified 213 focal noncalcific lesions with standard-dose FBP. Pooled lesion detection was higher for low-dose MBIR (79.3% [169/213]) compared with low-dose FBP (66.2% [141/213]) and ASIR (62.0% [132/213]) (p < 0.05). MBIR shows great potential for substantially reducing radiation doses at routine abdominal CT. Both FBP and ASIR are limited in this regard owing to reduced image quality and diagnostic capability. Further investigation is needed to determine the optimal dose level for MBIR that maintains adequate diagnostic performance. In general, objective and subjective image quality measurements do not necessarily correlate with diagnostic performance at ultralow-dose CT.

Reduced administered activity, reduced acquisition time, and preserved image quality for the new CZT camera.

PubMed

Oddstig, Jenny; Hedeer, Fredrik; Jögi, Jonas; Carlsson, Marcus; Hindorf, Cecilia; Engblom, Henrik

2013-02-01

For a 1-day myocardial perfusion SPECT (MPS) the recommendations for administered activity stated in the EANM guidelines results in an effective dose of up to 16 mSv per patient. Recently, a gamma camera system, based on cadmium zinc telluride (CZT) technology, was introduced. This technique has the potential to reduce the effective dose and scan time compared to the conventional NaI gamma camera. The aim of this study was to investigate if the effective dose can be reduced with a preserved image quality using CZT technology in MPS. In total, 150 patients were included in the study. All underwent a 1-day (99m)Tc-tetrofosmin stress-rest protocol and were divided into three subgroups (n = 50 in each group) with 4, 3, and 2.5 MBq/kg body weight of administered activity in the stress examination, respectively. The acquisition time was increased in proportion to the decrease in administered activity. All examinations were analyzed for image quality by visual grading on a 4-point scale (1 = poor, 2 = adequate, 3 = good, 4 = excellent), by two expert readers. The total effective dose (stress + rest) decreased from 9.3 to 5.8 mSv comparing 4 to 2.5 MBq/kg body weight. For the patients undergoing stress examination only (35%) the effective dose, administrating 2.5 MBq/kg, was 1.4 mSv. The image acquisition times for 2.5 MBq/kg body weight were 475 and 300 seconds (stress and rest) compared to 900 seconds for each when using conventional MPS. The average image quality was 3.7 ± 0.5, 3.8 ± 0.5, and 3.8 ± 0.4 for the stress images and 3.5 ± 0.6, 3.6 ± 0.6, and 3.5 ± 0.6 for the rest images and showed no statistically significant difference (P = .62) among the 4, 3, and 2.5 MBq/kg groups. The new CZT technology can be used to considerably decrease the effective dose and acquisition time for MPS with preserved high image quality.

In Vivo Small Animal Imaging using Micro-CT and Digital Subtraction Angiography

PubMed Central

Badea, C.T.; Drangova, M.; Holdsworth, D.W.; Johnson, G.A.

2009-01-01

Small animal imaging has a critical role in phenotyping, drug discovery, and in providing a basic understanding of mechanisms of disease. Translating imaging methods from humans to small animals is not an easy task. The purpose of this work is to review in vivo X-ray based small animal imaging, with a focus on in vivo micro-computed tomography (micro-CT) and digital subtraction angiography (DSA). We present the principles, technologies, image quality parameters and types of applications. We show that both methods can be used not only to provide morphological, but also functional information, such as cardiac function estimation or perfusion. Compared to other modalities, x-ray based imaging is usually regarded as being able to provide higher throughput at lower cost and adequate resolution. The limitations are usually associated with the relatively poor contrast mechanisms and potential radiation damage due to ionizing radiation, although the use of contrast agents and careful design of studies can address these limitations. We hope that the information will effectively address how x-ray based imaging can be exploited for successful in vivo preclinical imaging. PMID:18758005

Creation and Validation of a Simulator for Neonatal Brain Ultrasonography: A Pilot Study.

PubMed

Tsai, Andy; Barnewolt, Carol E; Prahbu, Sanjay P; Yonekura, Reimi; Hosmer, Andrew; Schulz, Noah E; Weinstock, Peter H

2017-01-01

Historically, skills training in performing brain ultrasonography has been limited to hours of scanning infants for lack of adequate synthetic models or alternatives. The aim of this study was to create a simulator and determine its utility as an educational tool in teaching the skills that can be used in performing brain ultrasonography on infants. A brain ultrasonography simulator was created using a combination of multi-modality imaging, three-dimensional printing, material and acoustic engineering, and sculpting and molding. Radiology residents participated prior to their pediatric rotation. The study included (1) an initial questionnaire and resident creation of three coronal images using the simulator; (2) brain ultrasonography lecture; (3) hands-on simulator practice; and (4) a follow-up questionnaire and re-creation of the same three coronal images on the simulator. A blinded radiologist scored the quality of the pre- and post-training images using metrics including symmetry of the images and inclusion of predetermined landmarks. Wilcoxon rank-sum test was used to compare pre- and post-training questionnaire rankings and image quality scores. Ten residents participated in the study. Analysis of pre- and post-training rankings showed improvements in technical knowledge and confidence, and reduction in anxiety in performing brain ultrasonography. Objective measures of image quality likewise improved. Mean reported value score for simulator training was high across participants who reported perceived improvements in scanning skills and enjoyment from simulator use, with interest in additional practice on the simulator and recommendations for its use. This pilot study supports the use of a simulator in teaching radiology residents the skills that can be used to perform brain ultrasonography. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Steer-PROP: a GRASE-PROPELLER sequence with interecho steering gradient pulses.

PubMed

Srinivasan, Girish; Rangwala, Novena; Zhou, Xiaohong Joe

2018-05-01

This study demonstrates a novel PROPELLER (periodically rotated overlapping parallel lines with enhanced reconstruction) pulse sequence, termed Steer-PROP, based on gradient and spin echo (GRASE), to reduce the imaging times and address phase errors inherent to GRASE. The study also illustrates the feasibility of using Steer-PROP as an alternative to single-shot echo planar imaging (SS-EPI) to produce distortion-free diffusion images in all imaging planes. Steer-PROP uses a series of blip gradient pulses to produce N (N = 3-5) adjacent k-space blades in each repetition time, where N is the number of gradient echoes in a GRASE sequence. This sampling strategy enables a phase correction algorithm to systematically address the GRASE phase errors as well as the motion-induced phase inconsistency. Steer-PROP was evaluated on phantoms and healthy human subjects at both 1.5T and 3.0T for T 2 - and diffusion-weighted imaging. Steer-PROP produced similar image quality as conventional PROPELLER based on fast spin echo (FSE), while taking only a fraction (e.g., 1/3) of the scan time. The robustness against motion in Steer-PROP was comparable to that of FSE-based PROPELLER. Using Steer-PROP, high quality and distortion-free diffusion images were obtained from human subjects in all imaging planes, demonstrating a considerable advantage over SS-EPI. The proposed Steer-PROP sequence can substantially reduce the scan times compared with FSE-based PROPELLER while achieving adequate image quality. The novel k-space sampling strategy in Steer-PROP not only enables an integrated phase correction method that addresses various sources of phase errors, but also minimizes the echo spacing compared with alternative sampling strategies. Steer-PROP can also be a viable alternative to SS-EPI to decrease image distortion in all imaging planes. Magn Reson Med 79:2533-2541, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Breast MRI at 7 Tesla with a bilateral coil and robust fat suppression.

PubMed

Brown, Ryan; Storey, Pippa; Geppert, Christian; McGorty, KellyAnne; Klautau Leite, Ana Paula; Babb, James; Sodickson, Daniel K; Wiggins, Graham C; Moy, Linda

2014-03-01

To develop a bilateral coil and fat suppressed T1-weighted sequence for 7 Tesla (T) breast MRI. A dual-solenoid coil and three-dimensional (3D) T1w gradient echo sequence with B1+ insensitive fat suppression (FS) were developed. T1w FS image quality was characterized through image uniformity and fat-water contrast measurements in 11 subjects. Signal-to-noise ratio (SNR) and flip angle maps were acquired to assess the coil performance. Bilateral contrast-enhanced and unilateral high resolution (0.6 mm isotropic, 6.5 min acquisition time) imaging highlighted the 7T SNR advantage. Reliable and effective FS and high image quality was observed in all subjects at 7T, indicating that the custom coil and pulse sequence were insensitive to high-field obstacles such as variable tissue loading. 7T and 3T image uniformity was similar (P=0.24), indicating adequate 7T B1+ uniformity. High 7T SNR and fat-water contrast enabled 0.6 mm isotropic imaging and visualization of a high level of fibroglandular tissue detail. 7T T1w FS bilateral breast imaging is feasible with a custom radiofrequency (RF) coil and pulse sequence. Similar image uniformity was achieved at 7T and 3T, despite different RF field behavior and variable coil-tissue interaction due to anatomic differences that might be expected to alter magnetic field patterns. Copyright © 2013 Wiley Periodicals, Inc.

Breast MRI at 7 Tesla with a Bilateral Coil and Robust Fat Suppression

PubMed Central

Brown, Ryan; Storey, Pippa; Geppert, Christian; McGorty, KellyAnne; Leite, Ana Paula Klautau; Babb, James; Sodickson, Daniel K.; Wiggins, Graham C.; Moy, Linda

2013-01-01

Purpose To develop a bilateral coil and optimized fat suppressed T1-weighted sequence for 7T breast MRI. Materials and Methods A dual-solenoid coil and 3D T1w gradient echo sequence with B1+ insensitive fat suppression (FS) were developed for 7T. T1w FS image quality was characterized through image uniformity and fat/water contrast measurements in 11 subjects. Signal-to-noise ratio (SNR) and flip angle maps were acquired to assess the coil performance. Bilateral contrast-enhanced and unilateral high resolution (0.6 mm isotropic, 6.5 min acquisition time) imaging highlighted the 7 T SNR advantage. Results Reliable and effective FS and high image quality was observed in all subjects at 7T, indicating that the custom coil and pulse sequence were insensitive to high-field obstacles such as variable tissue loading. 7T and 3T T1w FS image uniformity was similar (P=0.24), indicating adequate 7T B1+ uniformity. High 7T SNR and fat/water contrast enabled 0.6 mm isotropic imaging and visualization of a high level of fibroglandular tissue detail. Conclusion 7T T1w FS bilateral breast imaging is feasible with a custom RF coil and pulse sequence. Similar image uniformity was achieved at 7T and 3T, despite different RF field behavior and variable coil-tissue interaction due to anatomic differences that might be expected to alter magnetic field patterns. PMID:24123517

76 FR 68373 - Proposed Revision to Vintage Date Requirements

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-04

... foreign, while still ensuring that consumers are provided with adequate information as to the identity and... labels provide the consumer with adequate information as to the identity and quality of the product. The... mandate to ensure that consumers have adequate information about the quality and identity of the product...

Quality of Informal Care Is Multidimensional

PubMed Central

Christie, Juliette; Smith, G. Rush; Williamson, Gail M.; Lance, Charles. E.; Shovali, Tamar E.; Silva, Luciana

2010-01-01

Purpose To demonstrate that assessing quality of informal care involves more than merely determining whether care recipient needs for assistance with activities of daily living (ADLs) are satisfied on a routine basis. Potentially harmful behavior (PHB), adequate care, and exemplary care (EC) are conceptually distinct dimensions of quality of care. We investigated the extent to which these three dimensions also are empirically distinguishable. Design 237 care recipients completed the quality of care measures, and their caregivers completed psychosocial measures of depressed affect, life events, cognitive status, and perceived pre-illness relationship quality. Results Confirmatory factor analyses indicated that PHB, adequate care, and EC are empirically distinct factors. Although PHB was moderately related to EC, adequate care was not associated with PHB and was only slightly related to EC. Psychosocial variables were not related to adequate care but were differentially associated with PHB and EC, providing further evidence for the distinction between the measures of quality of care used in this study. Conclusions Assessing quality of informal care is a complex endeavor. ADL assistance can be adequate in the presence of PHB and/or the absence of EC. Declines in EC may signal increases in PHB, independent of adequacy of care. These findings produce a brief, portable, and more comprehensive instrument for assessing quality of informal care. PMID:19469607

MO-FG-CAMPUS-JeP2-02: Audiovisual Biofeedback Guided Respiratory-Gated MRI: An Investigation of Tumor Definition and Scan Time for Lung Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, D; Pollock, S; Keall, P

Purpose: Breathing consistency variations can cause respiratory-related motion blurring and artifacts and increase in MRI scan time due to inadequate respiratory-gating and discarding of breathing cycles. In a previous study the concept of audiovisual biofeedback (AV) guided respiratory-gated MRI was tested with healthy volunteers and it demonstrated image quality improvement on anatomical structures and scan time reduction. This study tests the applicability of AV-guided respiratorygated MRI for lung cancer in a prospective patient study. Methods: Image quality and scan time were investigated in thirteen lung cancer patients who underwent two 3T MRI sessions. In the first MRI session (pre-treatment), respiratory-gatedmore » MR images with free breathing (FB) and AV were acquired at inhalation and exhalation. An RF navigator placed on the liver dome was employed for the respiratory-gated MRI. This was repeated in the second MRI session (mid-treatment). Lung tumors were delineated on each dataset. FB and AV were compared in terms of (1) tumor definition assessed by lung tumor contours and (2) intra-patient scan time variation using the total image acquisition time of inhalation and exhalation datasets from the first and second MRI sessions across 13 lung cancer patients. Results: Compared to FB AV-guided respiratory-gated MRI improved image quality for contouring tumors with sharper boundaries and less blurring resulted in the improvement of tumor definition. Compared to FB the variation of intra-patient scan time with AV was reduced by 48% (p<0.001) from 54 s to 28 s. Conclusion: This study demonstrated that AV-guided respiratorygated MRI improved the quality of tumor images and fixed tumor definition for lung cancer. These results suggest that audiovisual biofeedback breathing guidance has the potential to control breathing for adequate respiratory-gating for lung cancer imaging and radiotherapy.« less

Fully automated motion correction in first-pass myocardial perfusion MR image sequences.

PubMed

Milles, Julien; van der Geest, Rob J; Jerosch-Herold, Michael; Reiber, Johan H C; Lelieveldt, Boudewijn P F

2008-11-01

This paper presents a novel method for registration of cardiac perfusion magnetic resonance imaging (MRI). The presented method is capable of automatically registering perfusion data, using independent component analysis (ICA) to extract physiologically relevant features together with their time-intensity behavior. A time-varying reference image mimicking intensity changes in the data of interest is computed based on the results of that ICA. This reference image is used in a two-pass registration framework. Qualitative and quantitative validation of the method is carried out using 46 clinical quality, short-axis, perfusion MR datasets comprising 100 images each. Despite varying image quality and motion patterns in the evaluation set, validation of the method showed a reduction of the average right ventricle (LV) motion from 1.26+/-0.87 to 0.64+/-0.46 pixels. Time-intensity curves are also improved after registration with an average error reduced from 2.65+/-7.89% to 0.87+/-3.88% between registered data and manual gold standard. Comparison of clinically relevant parameters computed using registered data and the manual gold standard show a good agreement. Additional tests with a simulated free-breathing protocol showed robustness against considerable deviations from a standard breathing protocol. We conclude that this fully automatic ICA-based method shows an accuracy, a robustness and a computation speed adequate for use in a clinical environment.

Improving the quality of child anthropometry: Manual anthropometry in the Body Imaging for Nutritional Assessment Study (BINA)

PubMed Central

2017-01-01

Anthropometric data collected in clinics and surveys are often inaccurate and unreliable due to measurement error. The Body Imaging for Nutritional Assessment Study (BINA) evaluated the ability of 3D imaging to correctly measure stature, head circumference (HC) and arm circumference (MUAC) for children under five years of age. This paper describes the protocol for and the quality of manual anthropometric measurements in BINA, a study conducted in 2016–17 in Atlanta, USA. Quality was evaluated by examining digit preference, biological plausibility of z-scores, z-score standard deviations, and reliability. We calculated z-scores and analyzed plausibility based on the 2006 WHO Child Growth Standards (CGS). For reliability, we calculated intra- and inter-observer Technical Error of Measurement (TEM) and Intraclass Correlation Coefficient (ICC). We found low digit preference; 99.6% of z-scores were biologically plausible, with z-score standard deviations ranging from 0.92 to 1.07. Total TEM was 0.40 for stature, 0.28 for HC, and 0.25 for MUAC in centimeters. ICC ranged from 0.99 to 1.00. The quality of manual measurements in BINA was high and similar to that of the anthropometric data used to develop the WHO CGS. We attributed high quality to vigorous training, motivated and competent field staff, reduction of non-measurement error through the use of technology, and reduction of measurement error through adequate monitoring and supervision. Our anthropometry measurement protocol, which builds on and improves upon the protocol used for the WHO CGS, can be used to improve anthropometric data quality. The discussion illustrates the need to standardize anthropometric data quality assessment, and we conclude that BINA can provide a valuable evaluation of 3D imaging for child anthropometry because there is comparison to gold-standard, manual measurements. PMID:29240796

The applied research of MRI with ASSET-EPI-FLAIR combined with 3D TOF MRA sequences in the assessment of patients with acute cerebral infarction.

PubMed

Lin, Zhichao; Guo, Zexiong; Qiu, Lin; Yang, Wanyoug; Lin, Mingxia

2016-12-01

Background To extend the time window for thrombolysis, reducing the time for diagnosis and detection of acute cerebral infarction seems to be warranted. Purpose To evaluate the feasibility of implementing an array spatial sensitivity technique (ASSET)-echo-planar imaging (EPI)-fluid attenuated inversion recovery (FLAIR) (AE-FLAIR) sequence into an acute cerebral infarction magnetic resonance (MR) evaluation protocol, and to assess the diagnostic value of AE-FLAIR combined with three-dimensional time-of-flight MR angiography (3D TOF MRA). Material and Methods A total of 100 patients (68 men, 32 women; age range, 44-82 years) with acute cerebral infarction, including 50 consecutive uncooperative and 50 cooperative patients, were evaluated with T1-weighted (T1W) imaging, T2-weighted (T2W) imaging, FLAIR, diffusion-weighted imaging (DWI), 3D TOF, EPI-FLAIR, and AE-FLAIR. Conventional FLAIR, EPI-FLAIR, and AE-FLAIR were assessed by two observers independently for image quality. The optimized group (AE-FLAIR and 3D TOF) and the control group (T1W imaging, T2W imaging, conventional FLAIR, DWI, and 3D TOF) were compared for evaluation time and diagnostic accuracy. Results One hundred and twenty-five lesions were detected and images having adequate diagnostic image quality were in 73% of conventional FLAIR, 62% of EPI-FLAIR, and 89% of AE-FLAIR. The detection time was 12 ± 1 min with 76% accuracy and 4 ± 0.5 min with 100% accuracy in the control and the optimized groups, respectively. Inter-observer agreements of κ = 0.78 and κ = 0.81 were for the optimized group and control group, respectively. Conclusion With reduced acquisition time and better image quality, AE-FLAIR combined with 3D TOF may be used as a rapid diagnosis tool in patients with acute cerebral infarction, especially in uncooperative patients.

SU-F-I-47: Optimizing Protocols for Image Quality and Dose in Abdominal CT of Large Patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, L; Yester, M

Purpose: Newer CT scanners are able to use scout views to adjust mA throughout the scan in order to achieve a given noise level. However, given constraints of radiologist preferences for kVp and rotation time, it may not be possible to achieve an acceptable noise level for large patients. A study was initiated to determine for which patients kVp and/or rotation time should be changed in order to achieve acceptable image quality. Methods: Patient scans were reviewed on two new Emergency Department scanners (Philips iCT) to identify patients over a large range of sizes. These iCTs were set with amore » limit of 500 mA to safeguard against a failure that might cause a CT scan to be (incorrectly) obtained at too-high mA. Scout views of these scans were assessed for both AP and LAT patient width and AP and LAT standard deviation in an ROI over the liver. Effective diameter and product of the scout standard deviations over the liver were both studied as possible metrics for identifying patients who would need kVp and/or rotation time changed. The mA used for the liver in the CT was compared to these metrics for those patients whose CT scans showed acceptable image quality. Results: Both effective diameter and product of the scout standard deviations over the liver result in similar predictions for which patients will require the kVp and/or rotation time to be changed to achieve an optimal combination of image quality and dose. Conclusion: Two mechanisms for CT technologists to determine based on scout characteristics what kVp, mA limit, and rotation time to use when DoseRight with our physicians’ preferred kVp and rotation time will not yield adequate image quality are described.« less

Advanced CT acquisition protocol with a third-generation dual-source CT scanner and iterative reconstruction technique for comprehensive prosthetic heart valve assessment.

PubMed

Faure, Marguerite E; Swart, Laurens E; Dijkshoorn, Marcel L; Bekkers, Jos A; van Straten, Marcel; Nieman, Koen; Parizel, Paul M; Krestin, Gabriel P; Budde, Ricardo P J

2018-05-01

Multidetector CT (MDCT) is a valuable tool for functional prosthetic heart valve (PHV) assessment. However, radiation exposure remains a concern. We assessed a novel CT-acquisition protocol for comprehensive PHV evaluation at limited dose. Patients with a PHV were scanned using a third-generation dual-source CT scanner (DSCT) and iterative reconstruction technique (IR). Three acquisitions were obtained: a non-enhanced scan; a contrast-enhanced, ECG-triggered, arterial CT angiography (CTA) scan with reconstructions at each 5 % of the R-R interval; and a delayed high-pitch CTA of the entire chest. Image quality was scored on a five-point scale. Radiation dose was obtained from the reported CT dose index (CTDI) and dose length product (DLP). We analysed 43 CT examinations. Mean image quality score was 4.1±1.4, 4.7±0.5 and 4.2±0.6 for the non-contrast-enhanced, arterial and delayed acquisitions, respectively, with a total mean image quality of 4.3±0.7. Mean image quality for leaflet motion was 3.9±1.4. Mean DLP was 28.2±17.1, 457.3±168.6 and 68.5±47.2 mGy.cm for the non-contrast-enhanced (n=40), arterial (n=43) and delayed acquisition (n=43), respectively. The mean total DLP was 569±208 mGy.cm and mean total radiation dose was 8.3±3.0 mSv (n=43). Comprehensive assessment of PHVs is possible using DSCT and IR at moderate radiation dose. • Prosthetic heart valve dysfunction is a potentially life-threatening condition. • Dual-source CT can adequately assess valve leaflet motion and anatomy. • We assessed a comprehensive protocol with three acquisitions for PHV evaluation. • This protocol is associated with good image quality and limited dose.

Clinical performance of a free-breathing spatiotemporally accelerated 3-D time-resolved contrast-enhanced pediatric abdominal MR angiography

PubMed Central

Yousaf, Ufra; Hsiao, Albert; Cheng, Joseph Y.; Alley, Marcus T.; Lustig, Michael; Pauly, John M.; Vasanawala, Shreyas S.

2015-01-01

Background Pediatric contrast-enhanced MR angiography is often limited by respiration, other patient motion and compromised spatiotemporal resolution. Objective To determine the reliability of a free-breathing spatiotemporally accelerated 3-D time-resolved contrast enhanced MR angiography method for depicting abdominal arterial anatomy in young children. Materials and methods With IRB approval and informed consent, we retrospectively identified 27 consecutive children (16 males and 11 females; mean age: 3.8 years, range: 14 days to 8.4 years) referred for contrast enhanced MR angiography at our institution, who had undergone free-breathing spatiotemporally accelerated time-resolved contrast enhanced MR angiography studies. An radio-frequency-spoiled gradient echo sequence with Cartesian variable density k-space sampling and radial view ordering, intrinsic motion navigation and intermittent fat suppression was developed. Images were reconstructed with soft-gated parallel imaging locally low-rank method to achieve both motion correction and high spatiotemporal resolution. Quality of delineation of 13 abdominal arteries in the reconstructed images was assessed independently by two radiologists on a five-point scale. Ninety-five percent confidence intervals of the proportion of diagnostically adequate cases were calculated. Interobserver agreements were also analyzed. Results Eleven out of 13 arteries achieved acceptable image quality (mean score range: 3.9–5.0) for both readers. Fair to substantial interobserver agreement was reached on nine arteries. Conclusion Free-breathing spatiotemporally accelerated 3-D time-resolved contrast enhanced MR angiography frequently yields diagnostic image quality for most abdominal arteries for pediatric contrast enhanced MR angiography. PMID:26040509

Extreme Tele-Echocardiography: Methodology for Remote Guidance of In-Flight Echocardiography Aboard the International Space Station

NASA Technical Reports Server (NTRS)

Martin, David S.; Borowski, Allan; Bungo, Michael W.; Gladding, Patrick; Greenberg, Neil; Hamilton, Doug; Levine, Benjamin D.; Lee, Stuart M.; Norwood, Kelly; Platts, Steven H.;

Reference-free ground truth metric for metal artifact evaluation in CT images.

PubMed

Kratz, Bärbel; Ens, Svitlana; Müller, Jan; Buzug, Thorsten M

2011-07-01

In computed tomography (CT), metal objects in the region of interest introduce data inconsistencies during acquisition. Reconstructing these data results in an image with star shaped artifacts induced by the metal inconsistencies. To enhance image quality, the influence of the metal objects can be reduced by different metal artifact reduction (MAR) strategies. For an adequate evaluation of new MAR approaches a ground truth reference data set is needed. In technical evaluations, where phantoms can be measured with and without metal inserts, ground truth data can easily be obtained by a second reference data acquisition. Obviously, this is not possible for clinical data. Here, an alternative evaluation method is presented without the need of an additionally acquired reference data set. The proposed metric is based on an inherent ground truth for metal artifacts as well as MAR methods comparison, where no reference information in terms of a second acquisition is needed. The method is based on the forward projection of a reconstructed image, which is compared to the actually measured projection data. The new evaluation technique is performed on phantom and on clinical CT data with and without MAR. The metric results are then compared with methods using a reference data set as well as an expert-based classification. It is shown that the new approach is an adequate quantification technique for artifact strength in reconstructed metal or MAR CT images. The presented method works solely on the original projection data itself, which yields some advantages compared to distance measures in image domain using two data sets. Beside this, no parameters have to be manually chosen. The new metric is a useful evaluation alternative when no reference data are available.

Broadband Phase Retrieval for Image-Based Wavefront Sensing

NASA Technical Reports Server (NTRS)

Dean, Bruce H.

2007-01-01

A focus-diverse phase-retrieval algorithm has been shown to perform adequately for the purpose of image-based wavefront sensing when (1) broadband light (typically spanning the visible spectrum) is used in forming the images by use of an optical system under test and (2) the assumption of monochromaticity is applied to the broadband image data. Heretofore, it had been assumed that in order to obtain adequate performance, it is necessary to use narrowband or monochromatic light. Some background information, including definitions of terms and a brief description of pertinent aspects of image-based phase retrieval, is prerequisite to a meaningful summary of the present development. Phase retrieval is a general term used in optics to denote estimation of optical imperfections or aberrations of an optical system under test. The term image-based wavefront sensing refers to a general class of algorithms that recover optical phase information, and phase-retrieval algorithms constitute a subset of this class. In phase retrieval, one utilizes the measured response of the optical system under test to produce a phase estimate. The optical response of the system is defined as the image of a point-source object, which could be a star or a laboratory point source. The phase-retrieval problem is characterized as image-based in the sense that a charge-coupled-device camera, preferably of scientific imaging quality, is used to collect image data where the optical system would normally form an image. In a variant of phase retrieval, denoted phase-diverse phase retrieval [which can include focus-diverse phase retrieval (in which various defocus planes are used)], an additional known aberration (or an equivalent diversity function) is superimposed as an aid in estimating unknown aberrations by use of an image-based wavefront-sensing algorithm. Image-based phase-retrieval differs from such other wavefront-sensing methods, such as interferometry, shearing interferometry, curvature wavefront sensing, and Shack-Hartmann sensing, all of which entail disadvantages in comparison with image-based methods. The main disadvantages of these non-image based methods are complexity of test equipment and the need for a wavefront reference.

Preliminary evaluation of a high-resolution workstation for diagnostic interpretation of portable radiographs

NASA Astrophysics Data System (ADS)

Honeyman-Buck, Janice C.; Huda, Walter; Palmer, Carole K.; Frost, Meryll M.; Moser, Robert; Staab, Edward V.

1995-04-01

A cost effectiveness study on the feasibility of using computed radiography (CR) instead of screen-film methods for portable radiographs indicates that we could only justify CR if film were eliminated. Before purchasing CR equipment, we needed to evaluate the use of softcopy to replace film for routine clinical use. The evaluation had to cover image quality, human factors, and efficiency measures. Screen-film radiographs were digitized and used to simulate CR in two studies. The first study evaluated the quality of digitized images and the workstation user interface. Twenty-one radiographs were selected at random from scopes in the radiology department, were digitized, and transferred to a megascan workstation. Five radiologists were asked to assess the quality of the images and the ease of operation of the workstation while an observer recorded their comments and scores. The second study evaluated the feasibility of using the workstation in a clinical environment. Four radiologists read adult and pediatric portable images in film and softcopy format. Reports were evaluated for differences and timing statistics were kept. The results of the first study indicate that image quality may be acceptable for diagnostic purposes and suggests some changes in the user interface. Newborn infant images were the least acceptable in softcopy, largely due to magnification artifacts introduced when viewing very small images. The evaluation was based on a digitizer as a simulator for a CR unit and the digitizer did not exhibit the same resolution characteristics as CR. Films that were unacceptable from the digitizer are expected to be acceptable with CR. The results of the second study indicated that the high resolution diagnostic workstation could be used in a clinical setting, and that the diagnostic readings were not significantly different between film and softcopy displays. The results also indicated that, depending on the radiologist and the type of images, more time was required to read from the workstation and that the increased time was spent using window/level and magnification/roam functions. This preliminary study suggests that the high resolution workstation developed at the University of Florida has adequate quality and functionality to be used for diagnostic interpretation of portable radiographs if given high resolution images. However, further investigation is indicated before we eliminate film in a CR environment.

A fast 4D cone beam CT reconstruction method based on the OSC-TV algorithm.

PubMed

Mascolo-Fortin, Julia; Matenine, Dmitri; Archambault, Louis; Després, Philippe

2018-01-01

Four-dimensional cone beam computed tomography allows for temporally resolved imaging with useful applications in radiotherapy, but raises particular challenges in terms of image quality and computation time. The purpose of this work is to develop a fast and accurate 4D algorithm by adapting a GPU-accelerated ordered subsets convex algorithm (OSC), combined with the total variation minimization regularization technique (TV). Different initialization schemes were studied to adapt the OSC-TV algorithm to 4D reconstruction: each respiratory phase was initialized either with a 3D reconstruction or a blank image. Reconstruction algorithms were tested on a dynamic numerical phantom and on a clinical dataset. 4D iterations were implemented for a cluster of 8 GPUs. All developed methods allowed for an adequate visualization of the respiratory movement and compared favorably to the McKinnon-Bates and adaptive steepest descent projection onto convex sets algorithms, while the 4D reconstructions initialized from a prior 3D reconstruction led to better overall image quality. The most suitable adaptation of OSC-TV to 4D CBCT was found to be a combination of a prior FDK reconstruction and a 4D OSC-TV reconstruction with a reconstruction time of 4.5 minutes. This relatively short reconstruction time could facilitate a clinical use.

Handheld ultrasound array imaging device

NASA Astrophysics Data System (ADS)

Hwang, Juin-Jet; Quistgaard, Jens

1999-06-01

A handheld ultrasound imaging device, one that weighs less than five pounds, has been developed for diagnosing trauma in the combat battlefield as well as a variety of commercial mobile diagnostic applications. This handheld device consists of four component ASICs, each is designed using the state of the art microelectronics technologies. These ASICs are integrated with a convex array transducer to allow high quality imaging of soft tissues and blood flow in real time. The device is designed to be battery driven or ac powered with built-in image storage and cineloop playback capability. Design methodologies of a handheld device are fundamentally different to those of a cart-based system. As system architecture, signal and image processing algorithm as well as image control circuit and software in this device is deigned suitably for large-scale integration, the image performance of this device is designed to be adequate to the intent applications. To elongate the battery life, low power design rules and power management circuits are incorporated in the design of each component ASIC. The performance of the prototype device is currently being evaluated for various applications such as a primary image screening tool, fetal imaging in Obstetrics, foreign object detection and wound assessment for emergency care, etc.

Fat-constrained 18F-FDG PET reconstruction using Dixon MR imaging and the origin ensemble algorithm

NASA Astrophysics Data System (ADS)

Wülker, Christian; Heinzer, Susanne; Börnert, Peter; Renisch, Steffen; Prevrhal, Sven

2015-03-01

Combined PET/MR imaging allows to incorporate the high-resolution anatomical information delivered by MRI into the PET reconstruction algorithm for improvement of PET accuracy beyond standard corrections. We used the working hypothesis that glucose uptake in adipose tissue is low. Thus, our aim was to shift 18F-FDG PET signal into image regions with a low fat content. Dixon MR imaging can be used to generate fat-only images via the water/fat chemical shift difference. On the other hand, the Origin Ensemble (OE) algorithm, a novel Markov chain Monte Carlo method, allows to reconstruct PET data without the use of forward- and back projection operations. By adequate modifications to the Markov chain transition kernel, it is possible to include anatomical a priori knowledge into the OE algorithm. In this work, we used the OE algorithm to reconstruct PET data of a modified IEC/NEMA Body Phantom simulating body water/fat composition. Reconstruction was performed 1) natively, 2) informed with the Dixon MR fat image to down-weight 18F-FDG signal in fatty tissue compartments in favor of adjacent regions, and 3) informed with the fat image to up-weight 18F-FDG signal in fatty tissue compartments, for control purposes. Image intensity profiles confirmed the visibly improved contrast and reduced partial volume effect at water/fat interfaces. We observed a 17+/-2% increased SNR of hot lesions surrounded by fat, while image quality was almost completely retained in fat-free image regions. An additional in vivo experiment proved the applicability of the presented technique in practice, and again verified the beneficial impact of fat-constrained OE reconstruction on PET image quality.

Salivary calculus diagnosis with 3-dimensional cone-beam computed tomography.

PubMed

Dreiseidler, Timo; Ritter, Lutz; Rothamel, Daniel; Neugebauer, Jörg; Scheer, Martin; Mischkowski, Robert A

2010-07-01

The objective of this study was to evaluate cone-beam CT (CBCT) diagnoses of sialoliths in the major salivary glands. Twenty-nine CBCT images containing salivary calculi were retrospectively evaluated for image quality and artifact influence. Additionally, the reproducibility of calculus measurement and the differences between CBCT measurements and ultrasonography (US) and histomorphometry (HM) measurements were determined. Diagnostic sensitivity and specificity calculations were based on the observations of 3 masked clinicians, who reviewed a total of 58 CBCT volumes. Salivary calculi were sufficiently visualized in all patients. Metal artifacts were detected in images of 7 patients, and movement artifacts in 2. CBCT calculi measurements were highly reproducible, with mean differences of less than 350 microm. Mean CBCT measurements of calculi diameters differed from mean US measurements by approximately 500 microm and differed from mean HM measurements by approximately 1 mm. For calculus diagnoses, the mean sensitivity and specificity were both 98.85%. Although poor image qualities and artifacts can reduce diagnostic information, salivary calculi can be evaluated adequately with CBCT. CBCT measurements of calculi are highly reproducible and differ little from measurements made with US and HM. Diagnostic sensitivity and specificity levels with CBCT are as high as or higher than those obtained with other diagnostic methods. Because of its high diagnostic-information-to-radiation-dose ratio, CBCT is the preferable imaging modality for salivary calculus diagnosis. Copyright (c) 2010 Mosby, Inc. All rights reserved.

Virtual microscopy in virtual tumor banking.

PubMed

Isabelle, M; Teodorovic, I; Oosterhuis, J W; Riegman, P H J; Passioukov, A; Lejeune, S; Therasse, P; Dinjens, W N M; Lam, K H; Oomen, M H A; Spatz, A; Ratcliffe, C; Knox, K; Mager, R; Kerr, D; Pezzella, F; Van Damme, B; Van de Vijver, M; Van Boven, H; Morente, M M; Alonso, S; Kerjaschki, D; Pammer, J; López-Guerrero, J A; Llombart-Bosch, A; Carbone, A; Gloghini, A; Van Veen, E B

2006-01-01

Many systems have already been designed and successfully used for sharing histology images over large distances, without transfer of the original glass slides. Rapid evolution was seen when digital images could be transferred over the Internet. Nowadays, sophisticated virtual microscope systems can be acquired, with the capability to quickly scan large batches of glass slides at high magnification and compress and store the large images on disc, which subsequently can be consulted through the Internet. The images are stored on an image server, which can give simple, easy to transfer pictures to the user specifying a certain magnification on any position in the scan. This offers new opportunities in histology review, overcoming the necessity of the dynamic telepathology systems to have compatible software systems and microscopes and in addition, an adequate connection of sufficient bandwidth. Consulting the images now only requires an Internet connection and a computer with a high quality monitor. A system of complete pathology review supporting biorepositories is described, based on the implementation of this technique in the European Human Frozen Tumor Tissue Bank (TuBaFrost).

TuBaFrost 6: virtual microscopy in virtual tumour banking.

PubMed

Teodorovic, I; Isabelle, M; Carbone, A; Passioukov, A; Lejeune, S; Jaminé, D; Therasse, P; Gloghini, A; Dinjens, W N M; Lam, K H; Oomen, M H A; Spatz, A; Ratcliffe, C; Knox, K; Mager, R; Kerr, D; Pezzella, F; van Damme, B; van de Vijver, M; van Boven, H; Morente, M M; Alonso, S; Kerjaschki, D; Pammer, J; Lopez-Guerrero, J A; Llombart Bosch, A; van Veen, E-B; Oosterhuis, J W; Riegman, P H J

2006-12-01

Many systems have already been designed and successfully used for sharing histology images over large distances, without transfer of the original glass slides. Rapid evolution was seen when digital images could be transferred over the Internet. Nowadays, sophisticated Virtual Microscope systems can be acquired, with the capability to quickly scan large batches of glass slides at high magnification and compress and store the large images on disc, which subsequently can be consulted through the Internet. The images are stored on an image server, which can give simple, easy to transfer pictures to the user specifying a certain magnification on any position in the scan. This offers new opportunities in histology review, overcoming the necessity of the dynamic telepathology systems to have compatible software systems and microscopes and in addition, an adequate connection of sufficient bandwidth. Consulting the images now only requires an Internet connection and a computer with a high quality monitor. A system of complete pathology review supporting bio-repositories is described, based on the implementation of this technique in the European Human Frozen Tumor Tissue Bank (TuBaFrost).

Very low-dose adult whole-body tumor imaging with F-18 FDG PET/CT

NASA Astrophysics Data System (ADS)

Krol, Andrzej; Naveed, Muhammad; McGrath, Mary; Lisi, Michele; Lavalley, Cathy; Feiglin, David

2015-03-01

The aim of this study was to evaluate if effective radiation dose due to PET component in adult whole-body tumor imaging with time-of-flight F-18 FDG PET/CT could be significantly reduced. We retrospectively analyzed data for 10 patients with the body mass index ranging from 25 to 50. We simulated F-18 FDG dose reduction to 25% of the ACR recommended dose via reconstruction of simulated shorter acquisition time per bed position scans from the acquired list data. F-18 FDG whole-body scans were reconstructed using time-of-flight OSEM algorithm and advanced system modeling. Two groups of images were obtained: group A with a standard dose of F-18 FDG and standard reconstruction parameters and group B with simulated 25% dose and modified reconstruction parameters, respectively. Three nuclear medicine physicians blinded to the simulated activity independently reviewed the images and compared diagnostic quality of images. Based on the input from the physicians, we selected optimal modified reconstruction parameters for group B. In so obtained images, all the lesions observed in the group A were visible in the group B. The tumor SUV values were different in the group A, as compared to group B, respectively. However, no significant differences were reported in the final interpretation of the images from A and B groups. In conclusion, for a small number of patients, we have demonstrated that F-18 FDG dose reduction to 25% of the ACR recommended dose, accompanied by appropriate modification of the reconstruction parameters provided adequate diagnostic quality of PET images acquired on time-of-flight PET/CT.

Photography in Dermatologic Surgery: Selection of an Appropriate Camera Type for a Particular Clinical Application.

PubMed

Chen, Brian R; Poon, Emily; Alam, Murad

2017-08-01

Photographs are an essential tool for the documentation and sharing of findings in dermatologic surgery, and various camera types are available. To evaluate the currently available camera types in view of the special functional needs of procedural dermatologists. Mobile phone, point and shoot, digital single-lens reflex (DSLR), digital medium format, and 3-dimensional cameras were compared in terms of their usefulness for dermatologic surgeons. For each camera type, the image quality, as well as the other practical benefits and limitations, were evaluated with reference to a set of ideal camera characteristics. Based on these assessments, recommendations were made regarding the specific clinical circumstances in which each camera type would likely be most useful. Mobile photography may be adequate when ease of use, availability, and accessibility are prioritized. Point and shoot cameras and DSLR cameras provide sufficient resolution for a range of clinical circumstances, while providing the added benefit of portability. Digital medium format cameras offer the highest image quality, with accurate color rendition and greater color depth. Three-dimensional imaging may be optimal for the definition of skin contour. The selection of an optimal camera depends on the context in which it will be used.

CT and MRI slice separation evaluation by LabView developed software.

PubMed

Acri, Giuseppe; Testagrossa, Barbara; Sestito, Angela; Bonanno, Lilla; Vermiglio, Giuseppe

2018-02-01

The efficient use of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) equipment necessitates establishing adequate quality-control (QC) procedures. In particular, the accuracy of slice separation, during multislices acquisition, requires scan exploration of phantoms containing test objects. To simplify such procedures, a novel phantom and a computerised LabView-based procedure have been devised, enabling determination the midpoint of full width at half maximum (FWHM) in real time while the distance from the profile midpoint of two progressive images is evaluated and measured. The results were compared with those obtained by processing the same phantom images with commercial software. To validate the proposed methodology the Fisher test was conducted on the resulting data sets. In all cases, there was no statistically significant variation between the commercial procedure and the LabView one, which can be used on any CT and MRI diagnostic devices. Copyright © 2017. Published by Elsevier GmbH.

Acoustic imaging and mirage effects with high transmittance in a periodically perforated metal slab

NASA Astrophysics Data System (ADS)

Zhao, Sheng-Dong; Wang, Yue-Sheng; Zhang, Chuanzeng

2016-11-01

In this paper, we present a high-quality superlens to focus acoustic waves using a periodically perforated metallic structure which is made of zinc and immersed in water. By changing a geometrical parameter gradually, a kind of gradient-index phononic crystal lens is designed to attain the mirage effects. The acoustic waves can propagate along an arc-shaped trajectory which is precisely controlled by the angle and frequency of the incident waves. The negative refraction imaging effect depends delicately on the transmittance of the solid structure. The acoustic impedance matching between the solid and the liquid proposed in this article, which is determined by the effective density and group velocity of the unit-cell, is significant for overcoming the inefficiency problem of acoustic devices. This study focuses on how to obtain the high transmittance imaging and mirage effects based on the adequate material selection and geometrical design.

Seismic imaging of post-glacial sediments - test study before Spitsbergen expedition

NASA Astrophysics Data System (ADS)

Szalas, Joanna; Grzyb, Jaroslaw; Majdanski, Mariusz

2017-04-01

This work presents results of the analysis of reflection seismic data acquired from testing area in central Poland. For this experiment we used total number of 147 vertical component seismic stations (DATA-CUBE and Reftek "Texan") with accelerated weight drop (PEG-40). The profile was 350 metres long. It is a part of pilot study for future research project on Spitsbergen. The purpose of the study is to recognise the characteristics of seismic response of post-glacial sediments in order to design the most adequate survey acquisition parameters and processing sequence for data from Spitsbergen. Multiple tests and comparisons have been performed to obtain the best possible quality of seismic image. In this research we examine the influence of receiver interval size, front mute application and surface wave attenuation attempts. Although seismic imaging is the main technique we are planning to support this analysis with additional data from traveltime tomography, MASW and other a priori information.

Detection of infragenual arterial disease using noncontrast-enhanced MR angiography in patients with diabetes

PubMed Central

Liu, Xin; Zhang, Na; Fan, Zhaoyang; Feng, Fei; Yang, Qi; Zheng, Hairong; Liu, Pengcheng; Li, Debiao

2013-01-01

Purpose To evaluate the diagnostic performance of a newly developed noncontrast-enhanced MR angiography (NCE-MRA) technique using flow-sensitive dephasing (FSD) prepared steady-state free precession (SSFP) for detecting calf arterial disease in patients with diabetes. Materials and Methods Forty-five patients with diabetes who underwent routine CE-MRA of lower extremities were recruited for NCE-MRA at the calf on a 1.5T MR system. Image quality evaluated on a four-point scale and diagnostic performance for detecting more than 50% arterial stenosis were statistically analyzed, using CE-MRA as the standard of reference. Results A total of 264 calf arterial segments were obtained in the 45 patients with 88 legs. The percentage of diagnostic arterial segments was all 98% for NCE- and CE-MRA. The image quality, SNR, CNR was 3.3, 177, 138 and 3.5, 103, 99 for NCE-MRA and CE-MRA respectively. The average sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of NCE-MRA were 97%, 96%, 90%, 99%, and 96%, respectively on a per-segment basis and 90%, 84%, 82%, 91%, and 87%, respectively on a per-patients basis. Conclusion The NCE-MRA technique demonstrates adequate image quality in the delineation of calf arteries and consistent diagnostic performance for detecting significant stenosis with CE-MRA in patients with diabetes. PMID:24925770

Remote clinical assessment of gastrointestinal endoscopy (tele-endoscopy): an initial experience.

PubMed Central

Kim, C. Y.; Etemad, B.; Glenn, T. F.; Mackey, H. A.; Viator, G. E.; Wallace, M. B.; Mokhashi, M. S.; Cotton, P. B.; Hawes, R. H.

2000-01-01

BACKGROUND: Gastrointestinal (GI) endoscopy is an effective tool to screen for cancers of the digestive tract. However, access to endoscopy is limited in many parts of South Carolina. This trial is a part of a prospective multi-part study for remote cancer screening in coastal South Carolina. This pilot study was to evaluate the quality of tele-endoscopy for cancer screening. METHODS: 10 patients scheduled for endoscopic procedures were observed simultaneously by the endoscopist and a remote observer connected over a 512 kbps ISDN line. Findings by both were compared for concordance on malignant or premalignant lesions. RESULTS: The image quality was adequate to support remote diagnosis of GI cancer and abnormal lesions by an experienced observer. However, assessment of the esophagogastric junction for Barrett's esophagus was equivocal. CONCLUSIONS: Overall, our tele-endoscopy setup shows great promise for remote supervision or observation of endoscopic procedures done by nurse endoscopists. Tele-endoscopy is both adequate and feasible for diagnosis of most gastrointestinal lesions. Subtle lesions still may be missed in our current setup. However, improvements are being made in our setup to address the problem with resolution prior to further evaluation. PMID:11079918

[Development of a Text-Data Based Learning Tool That Integrates Image Processing and Displaying].

PubMed

Shinohara, Hiroyuki; Hashimoto, Takeyuki

2015-01-01

We developed a text-data based learning tool that integrates image processing and displaying by Excel. Knowledge required for programing this tool is limited to using absolute, relative, and composite cell references and learning approximately 20 mathematical functions available in Excel. The new tool is capable of resolution translation, geometric transformation, spatial-filter processing, Radon transform, Fourier transform, convolutions, correlations, deconvolutions, wavelet transform, mutual information, and simulation of proton density-, T1-, and T2-weighted MR images. The processed images of 128 x 128 pixels or 256 x 256 pixels are observed directly within Excel worksheets without using any particular image display software. The results of image processing using this tool were compared with those using C language and the new tool was judged to have sufficient accuracy to be practically useful. The images displayed on Excel worksheets were compared with images using binary-data display software. This comparison indicated that the image quality of the Excel worksheets was nearly equal to the latter in visual impressions. Since image processing is performed by using text-data, the process is visible and facilitates making contrasts by using mathematical equations within the program. We concluded that the newly developed tool is adequate as a computer-assisted learning tool for use in medical image processing.

Comparison of fluoro and cine coronary angiography: balancing acceptable outcomes with a reduction in radiation dose.

PubMed

Olcay, Ayhan; Guler, Ekrem; Karaca, Ibrahim Oguz; Omaygenc, Mehmet Onur; Kizilirmak, Filiz; Olgun, Erkam; Yenipinar, Esra; Cakmak, Huseyin Altug; Duman, Dursun

2015-04-01

Use of last fluoro hold (LFH) mode in fluoroscopy, which enables the last live image to be saved and displayed, could reduce radiation during percutaneous coronary intervention when compared with cine mode. No previous study compared coronary angiography radiation doses and image quality between LFH and conventional cine mode techniques. We compared cumulative dose-area product (DAP), cumulative air kerma, fluoroscopy time, contrast use, interobserver variability of visual assessment between LFH angiography, and conventional cine angiography techniques. Forty-six patients were prospectively enrolled into the LFH group and 82 patients into the cine angiography group according to operator decision. Mean cumulative DAP was higher in the cine group vs the LFH group (50058.98 ± 53542.71 mGy•cm² vs 11349.2 ± 8796.46 mGy•cm²; P<.001). Mean fluoroscopy times were higher in the cine group vs the LFH group (3.87 ± 5.08 minutes vs 1.66 ± 1.51 minutes; P<.01). Mean contrast use was higher in the cine group vs the LFH group (112.07 ± 43.79 cc vs 88.15 ± 23.84 cc; P<.001). Mean value of Crombach's alpha was not statistically different between visual estimates of three operators between cine and LFH angiography groups (0.66680 ± 0.19309 vs 0.54193 ± 0.31046; P=.20). Radiation doses, contrast use, and fluoroscopy times are lower in fluoroscopic LFH angiography vs cine angiography. Interclass variability of visual stenosis estimation between three operators was not different between cine and LFH groups. Fluoroscopic LFH images conventionally have inferior diagnostic quality when compared with cine coronary angiography, but with new angiographic systems with improved LFH image quality, these images may be adequate for diagnostic coronary angiography.

High-frequency transducers for point-of-care ultrasound applications: what is the optimal frequency range?

PubMed

Adhikari, Srikar

2014-06-01

To compare images obtained using two linear transducers with a different range of frequencies, and to determine if there is a significant difference in the quality of images between the two transducers for medical decision-making. This was a single-blinded, cross-sectional study at an academic medical center. Twenty-five emergency medicine clinical scenarios with ultrasound images (using both 10-5 and 14-5 MHz transducers) covering a variety of point-of-care ultrasound applications were presented to four emergency physician sonographers. They were blinded to the study hypothesis and type of the transducer used to obtain the images. On a scale of 1-10, the mean image quality rating for 10-5 MHz transducer was 7.09 (95 % CI 6.73-7.45) and 6.49 (95 % CI 5.99-6.99) for 14-5 MHz transducer. In the majority of cases (84 %, 95 % CI 75.7-92.3 %), sonographers indicated that images obtained with a 10-5 MHz transducer were satisfactory for medical decision-making. They preferred images obtained with a 10-5 MHz transducer over 14-5 MHz transducer in 39 % (95 % CI 30-50 %) of cases. The images obtained with a 14-5 MHz transducer were preferred over 10-5 MHz transducer in only 16 % (95 % CI 7.7-24.3 %) of the cases. The 14-5 MHz transducer has a slight advantage over 10-5 MHz transducer for ocular, upper airway, and musculoskeletal (tendon) ultrasound applications. A 10-5 MHz linear transducer is adequate to obtain images that can be used for medical decision-making for a variety of point-of-care ultrasound applications.

New Capabilities With Dry Silver Recording Materials

NASA Astrophysics Data System (ADS)

Morgan, David A.

1987-04-01

Dry Silver technology was discovered at 3M and introduced into various imaging applications in the mid-sixties. In the early 1980's, quality films and papers with extended spectral responses, greater dynamic ranges, and improved sensitivity and edge acuity were introduced into sophisticated imaging systems. These products also have improved shelf life at elevated storage temperatures, and improved print stability. At the present time, 3M is developing a full-color dry silver product. This product has the same rapid-access, easy-to-use characteristics as the black and white dry silver recording materials. It has high resolution, long gray scale, and adequate sensitivity for CRT's and other electronically addressable exposure devices. The product can be processed in the same processors used for the black and white dry silver products.

Three Software Tools for Viewing Sectional Planes, Volume Models, and Surface Models of a Cadaver Hand.

PubMed

Chung, Beom Sun; Chung, Min Suk; Shin, Byeong Seok; Kwon, Koojoo

2018-02-19

The hand anatomy, including the complicated hand muscles, can be grasped by using computer-assisted learning tools with high quality two-dimensional images and three-dimensional models. The purpose of this study was to present up-to-date software tools that promote learning of stereoscopic morphology of the hand. On the basis of horizontal sectioned images and outlined images of a male cadaver, vertical planes, volume models, and surface models were elaborated. Software to browse pairs of the sectioned and outlined images in orthogonal planes and software to peel and rotate the volume models, as well as a portable document format (PDF) file to select and rotate the surface models, were produced. All of the software tools were downloadable free of charge and usable off-line. The three types of tools for viewing multiple aspects of the hand could be adequately employed according to individual needs. These new tools involving the realistic images of a cadaver and the diverse functions are expected to improve comprehensive knowledge of the hand shape. © 2018 The Korean Academy of Medical Sciences.

Three Software Tools for Viewing Sectional Planes, Volume Models, and Surface Models of a Cadaver Hand

PubMed Central

2018-01-01

Background The hand anatomy, including the complicated hand muscles, can be grasped by using computer-assisted learning tools with high quality two-dimensional images and three-dimensional models. The purpose of this study was to present up-to-date software tools that promote learning of stereoscopic morphology of the hand. Methods On the basis of horizontal sectioned images and outlined images of a male cadaver, vertical planes, volume models, and surface models were elaborated. Software to browse pairs of the sectioned and outlined images in orthogonal planes and software to peel and rotate the volume models, as well as a portable document format (PDF) file to select and rotate the surface models, were produced. Results All of the software tools were downloadable free of charge and usable off-line. The three types of tools for viewing multiple aspects of the hand could be adequately employed according to individual needs. Conclusion These new tools involving the realistic images of a cadaver and the diverse functions are expected to improve comprehensive knowledge of the hand shape. PMID:29441756

iPhone 4s and iPhone 5s Imaging of the Eye.

PubMed

Jalil, Maaz; Ferenczy, Sandor R; Shields, Carol L

2017-01-01

To evaluate the technical feasibility of a consumer-grade cellular iPhone camera as an ocular imaging device compared to existing ophthalmic imaging equipment for documentation purposes. A comparison of iPhone 4s and 5s images was made with external facial images (macrophotography) using Nikon cameras, slit-lamp images (microphotography) using Zeiss photo slit-lamp camera, and fundus images (fundus photography) using RetCam II. In an analysis of six consecutive patients with ophthalmic conditions, both iPhones achieved documentation of external findings (macrophotography) using standard camera modality, tap to focus, and built-in flash. Both iPhones achieved documentation of anterior segment findings (microphotography) during slit-lamp examination through oculars. Both iPhones achieved fundus imaging using standard video modality with continuous iPhone illumination through an ophthalmic lens. Comparison to standard ophthalmic cameras, macrophotography and microphotography were excellent. In comparison to RetCam fundus photography, iPhone fundus photography revealed smaller field and was technically more difficult to obtain, but the quality was nearly similar to RetCam. iPhone versions 4s and 5s can provide excellent ophthalmic macrophotography and microphotography and adequate fundus photography. We believe that iPhone imaging could be most useful in settings where expensive, complicated, and cumbersome imaging equipment is unavailable.

Comparative imaging study in ultrasound, MRI, CT, and DSA using a multimodality renal artery phantom

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, Deirdre M.; Fagan, Andrew J.; Moran, Carmel M.

2011-02-15

Purpose: A range of anatomically realistic multimodality renal artery phantoms consisting of vessels with varying degrees of stenosis was developed and evaluated using four imaging techniques currently used to detect renal artery stenosis (RAS). The spatial resolution required to visualize vascular geometry and the velocity detection performance required to adequately characterize blood flow in patients suffering from RAS are currently ill-defined, with the result that no one imaging modality has emerged as a gold standard technique for screening for this disease. Methods: The phantoms, which contained a range of stenosis values (0%, 30%, 50%, 70%, and 85%), were designed formore » use with ultrasound, magnetic resonance imaging, x-ray computed tomography, and x-ray digital subtraction angiography. The construction materials used were optimized with respect to their ultrasonic speed of sound and attenuation coefficient, MR relaxometry (T{sub 1},T{sub 2}) properties, and Hounsfield number/x-ray attenuation coefficient, with a design capable of tolerating high-pressure pulsatile flow. Fiducial targets, incorporated into the phantoms to allow for registration of images among modalities, were chosen to minimize geometric distortions. Results: High quality distortion-free images of the phantoms with good contrast between vessel lumen, fiducial markers, and background tissue to visualize all stenoses were obtained with each modality. Quantitative assessments of the grade of stenosis revealed significant discrepancies between modalities, with each underestimating the stenosis severity for the higher-stenosed phantoms (70% and 85%) by up to 14%, with the greatest discrepancy attributable to DSA. Conclusions: The design and construction of a range of anatomically realistic renal artery phantoms containing varying degrees of stenosis is described. Images obtained using the main four diagnostic techniques used to detect RAS were free from artifacts and exhibited adequate contrast to allow for quantitative measurements of the degree of stenosis in each phantom. Such multimodality phantoms may prove useful in evaluating current and emerging US, MRI, CT, and DSA technology.« less

Remote assessment of acne: the use of acne grading tools to evaluate digital skin images.

PubMed

Bergman, Hagit; Tsai, Kenneth Y; Seo, Su-Jean; Kvedar, Joseph C; Watson, Alice J

2009-06-01

Digital imaging of dermatology patients is a novel approach to remote data collection. A number of assessment tools have been developed to grade acne severity and to track clinical progress over time. Although these tools have been validated when used in a face-to-face setting, their efficacy and reliability when used to assess digital images have not been examined. The main purpose of this study was to determine whether specific assessment tools designed to grade acne during face-to-face visits can be applied to the evaluation of digital images. The secondary purpose was to ascertain whether images obtained by subjects are of adequate quality to allow such assessments to be made. Three hundred (300) digital images of patients with mild to moderate facial inflammatory acne from an ongoing randomized-controlled study were included in this analysis. These images were obtained from 20 patients and consisted of sets of 3 images taken over time. Of these images, 120 images were captured by subjects themselves and 180 were taken by study staff. Subjects were asked to retake their photographs if the initial images were deemed of poor quality by study staff. Images were evaluated by two dermatologists-in-training using validated acne assessment measures: Total Inflammatory Lesion Count, Leeds technique, and the Investigator's Global Assessment. Reliability of raters was evaluated using correlation coefficients and kappa statistics. Of the different acne assessment measures tested, the inter-rater reliability was highest for the total inflammatory lesion count (r = 0.871), but low for the Leeds technique (kappa = 0.381) and global assessment (kappa = 0.3119). Raters were able to evaluate over 89% of all images using each type of acne assessment measure despite the fact that images obtained by study staff were of higher quality than those obtained by patients (p < 0.001). Several existing clinical assessment measures can be used to evaluate digital images obtained from subjects with inflammatory acne lesions. The level of inter-rater agreement is highly variable across assessment measures, and we found the Total Inflammatory Lesion Count to be the most reliable. This measure could be used to allow a dermatologist to remotely track a patient's progress over time.

Region 9: California Adequate Letter (1/22/2018)

EPA Pesticide Factsheets

This December 19, 2017 letter form EPA, finding adequate certain motor vehicle emissions budgets for the 2006 fine particulate matter (PM2.5) National Ambient Air Quality Standars in the Final 2016 Air Quality Managemnet Plan for the South Coast area (2016

Patient dose, gray level and exposure index with a computed radiography system

NASA Astrophysics Data System (ADS)

Silva, T. R.; Yoshimura, E. M.

2014-02-01

Computed radiography (CR) is gradually replacing conventional screen-film system in Brazil. To assess image quality, manufactures provide the calculation of an exposure index through the acquisition software of the CR system. The objective of this study is to verify if the CR image can be used as an evaluator of patient absorbed dose too, through a relationship between the entrance skin dose and the exposure index or the gray level values obtained in the image. The CR system used for this study (Agfa model 30-X with NX acquisition software) calculates an exposure index called Log of the Median (lgM), related to the absorbed dose to the IP. The lgM value depends on the average gray level (called Scan Average Level (SAL)) of the segmented pixel value histogram of the whole image. A Rando male phantom was used to simulate a human body (chest and head), and was irradiated with an X-ray equipment, using usual radiologic techniques for chest exams. Thermoluminescent dosimeters (LiF, TLD100) were used to evaluate entrance skin dose and exit dose. The results showed a logarithm relation between entrance dose and SAL in the image center, regardless of the beam filtration. The exposure index varies linearly with the entrance dose, but the angular coefficient is beam quality dependent. We conclude that, with an adequate calibration, the CR system can be used to evaluate the patient absorbed dose.

A dataset describing brooding in three species of South African brittle stars, comprising seven high-resolution, micro X-ray computed tomography scans.

PubMed

Landschoff, Jannes; Du Plessis, Anton; Griffiths, Charles L

2015-01-01

Brooding brittle stars have a special mode of reproduction whereby they retain their eggs and juveniles inside respiratory body sacs called bursae. In the past, studying this phenomenon required disturbance of the sample by dissecting the adult. This caused irreversible damage and made the sample unsuitable for future studies. Micro X-ray computed tomography (μCT) is a promising technique, not only to visualise juveniles inside the bursae, but also to keep the sample intact and make the dataset of the scan available for future reference. Seven μCT scans of five freshly fixed (70 % ethanol) individuals, representing three differently sized brittle star species, provided adequate image quality to determine the numbers, sizes and postures of internally brooded young, as well as anatomy and morphology of adults. No staining agents were necessary to achieve high-resolution, high-contrast images, which permitted visualisations of both calcified and soft tissue. The raw data (projection and reconstruction images) are publicly available for download from GigaDB. Brittle stars of all sizes are suitable candidates for μCT imaging. This explicitly adds a new technique to the suite of tools available for studying the development of internally brooded young. The purpose of applying the technique was to visualise juveniles inside the adult, but because of the universally good quality of the dataset, the images can also be used for anatomical or comparative morphology-related studies of adult structures.

Randomized Clinical Trial of Virtual Reality Simulation Training for Transvaginal Gynecologic Ultrasound Skills.

PubMed

Chao, Coline; Chalouhi, Gihad E; Bouhanna, Philippe; Ville, Yves; Dommergues, Marc

2015-09-01

To compare the impact of virtual reality simulation training and theoretical teaching on the ability of inexperienced trainees to produce adequate virtual transvaginal ultrasound images. We conducted a randomized controlled trial with parallel groups. Participants included inexperienced residents starting a training program in Paris. The intervention consisted of 40 minutes of virtual reality simulation training using a haptic transvaginal simulator versus 40 minutes of conventional teaching including a conference with slides and videos and answers to the students' questions. The outcome was a 19-point image quality score calculated from a set of 4 images (sagittal and coronal views of the uterus and left and right ovaries) produced by trainees immediately after the intervention, using the same simulator on which a new virtual patient had been uploaded. Experts assessed the outcome on stored images, presented in a random order, 2 months after the trial was completed. They were blinded to group assignment. The hypothesis was an improved outcome in the intervention group. Randomization was 1 to 1. The mean score was significantly greater in the simulation group (n = 16; mean score, 12; SEM, 0.8) than the control group (n = 18; mean score, 9; SEM, 1.0; P= .0302). The quality of virtual vaginal images produced by inexperienced trainees was greater immediately after a single virtual reality simulation training session than after a single theoretical teaching session. © 2015 by the American Institute of Ultrasound in Medicine.

Measurement of luminance noise and chromaticity noise of LCDs with a colorimeter and a color camera

NASA Astrophysics Data System (ADS)

Roehrig, H.; Dallas, W. J.; Krupinski, E. A.; Redford, Gary R.

2007-09-01

This communication focuses on physical evaluation of image quality of displays for applications in medical imaging. In particular we were interested in luminance noise as well as chromaticity noise of LCDs. Luminance noise has been encountered in the study of monochrome LCDs for some time, but chromaticity noise is a new type of noise which has been encountered first when monochrome and color LCDs were compared in an ROC study. In this present study one color and one monochrome 3 M-pixel LCDs were studied. Both were DICOM calibrated with equal dynamic range. We used a Konica Minolta Chroma Meter CS-200 as well as a Foveon color camera to estimate luminance and chrominance variations of the displays. We also used a simulation experiment to estimate luminance noise. The measurements with the colorimeter were consistent. The measurements with the Foveon color camera were very preliminary as color cameras had never been used for image quality measurements. However they were extremely promising. The measurements with the colorimeter and the simulation results showed that the luminance and chromaticity noise of the color LCD were larger than that of the monochrome LCD. Under the condition that an adequate calibration method and image QA/QC program for color displays are available, we expect color LCDs may be ready for radiology in very near future.

A risk index for pediatric patients undergoing diagnostic imaging with 99mTc-dimercaptosuccinic acid that accounts for body habitus

NASA Astrophysics Data System (ADS)

O'Reilly, Shannon E.; Plyku, Donika; Sgouros, George; Fahey, Frederic H.; Treves, S. Ted; Frey, Eric C.; Bolch, Wesley E.

2016-03-01

Published guidelines for administered activity to pediatric patients undergoing diagnostic nuclear medicine imaging are currently obtained through expert consensus of the minimum values as a function of body weight as required to yield diagnostic quality images. We have previously shown that consideration of body habitus is also important in obtaining diagnostic quality images at the lowest administered activity. The objective of this study was to create a series of computational phantoms that realistically portray the anatomy of the pediatric patient population which can be used to develop and validate techniques to minimize radiation dose while maintaining adequate image quality. To achieve this objective, we have defined an imaging risk index that may be used in future studies to develop pediatric patient dosing guidelines. A population of 48 hybrid phantoms consisting of non-uniform B-spline surfaces and polygon meshes was generated. The representative ages included the newborn, 1 year, 5 year, 10 year and 15 year male and female. For each age, the phantoms were modeled at their 10th, 50th, and 90th height percentile each at a constant 50th weight percentile. To test the impact of kidney size, the newborn phantoms were modeled with the following three kidney volumes:  -15%, average, and  +15%. To illustrate the impact of different morphologies on dose optimization, we calculated the effective dose for each phantom using weight-based 99mTc-DMSA activity administration. For a given patient weight, body habitus had a considerable effect on effective dose. Substantial variations were observed in the risk index between the 10th and 90th percentile height phantoms from the 50th percentile phantoms for a given age, with the greatest difference being 18%. There was a dependence found between kidney size and risk of radiation induced kidney cancer, with the highest risk indices observed in newborns with the smallest kidneys. Overall, the phantoms and techniques in this study can be used to provide data to refine dosing guidelines for pediatric nuclear imaging studies while taking into account the effects on both radiation dose and image quality. This work was supported by:R01 EB013558 with the National Institute for Biomedical Imaging and Bioengineering (NIBIB).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chu, William, E-mail: William.Chu@sunnybrook.ca; Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario; Staruch, Robert M.

Purpose: To evaluate the feasibility of magnetic resonance–guided high-intensity focused ultrasound (MR-HIFU) mild hyperthermia in deep tissue targets for enhancing radiation therapy and chemotherapy in the context of recurrent rectal cancer. A preclinical study was performed to evaluate the safety and performance of MR-HIFU mild hyperthermia. A prospective imaging study was performed in volunteers with rectal cancer to evaluate MR thermometry quality near the rectum and accessibility of rectal tumors using MR-HIFU. Methods and Materials: Mild hyperthermia was performed in pig thigh (9 sonications, 6 pigs) using a clinical MR-HIFU system. Targets near the rectal wall and deep thigh weremore » evaluated. Thermal maps obtained in 6 planes every 3.2 seconds were used to control sonications in 18-mm diameter treatment regions at temperatures of 42°C to 42.5°C for 10 to 60 minutes. Volunteer imaging-only studies to assess the quality of MR thermometry (without heating) were approved by the institutional research ethics board. Anatomic and MR thermometry images were acquired in consenting volunteers with rectal cancer. In 3 of 6 study participants, rectal filling with saline was used to reduce motion-related MR thermometry artifacts near the tumor. Results: In pigs, mean target temperature matched the desired hyperthermia temperature within 0.2°C; temporal standard deviation ≤0.5°C. With optimized control thresholds, no undesired tissue damage was observed. In human volunteers, MR temperature measurements had adequate precision and stability, especially when rectal filling was used to reduce bowel motion. Conclusions: In pigs, MR-HIFU can safely deliver mild hyperthermia (41°C-43°C) to a targeted volume for 30 minutes. In humans, careful patient selection and preparation will enable adequate targeting for recurrent rectal cancers and sufficient MR temperature mapping stability to control mild hyperthermia. These results enable human trials of MR-HIFU hyperthermia.« less

Q-controlled amplitude modulation atomic force microscopy in liquids: An analysis

NASA Astrophysics Data System (ADS)

Hölscher, H.; Schwarz, U. D.

2006-08-01

An analysis of amplitude modulation atomic force microscopy in liquids is presented with respect to the application of the Q-Control technique. The equation of motion is solved by numerical and analytic methods with and without Q-Control in the presence of a simple model interaction force adequate for many liquid environments. In addition, the authors give an explicit analytical formula for the tip-sample indentation showing that higher Q factors reduce the tip-sample force. It is found that Q-Control suppresses unwanted deformations of the sample surface, leading to the enhanced image quality reported in several experimental studies.

Finite Element-Based Mechanical Assessment of Bone Quality on the Basis of In Vivo Images.

PubMed

Pahr, Dieter H; Zysset, Philippe K

2016-12-01

Beyond bone mineral density (BMD), bone quality designates the mechanical integrity of bone tissue. In vivo images based on X-ray attenuation, such as CT reconstructions, provide size, shape, and local BMD distribution and may be exploited as input for finite element analysis (FEA) to assess bone fragility. Further key input parameters of FEA are the material properties of bone tissue. This review discusses the main determinants of bone mechanical properties and emphasizes the added value, as well as the important assumptions underlying finite element analysis. Bone tissue is a sophisticated, multiscale composite material that undergoes remodeling but exhibits a rather narrow band of tissue mineralization. Mechanically, bone tissue behaves elastically under physiologic loads and yields by cracking beyond critical strain levels. Through adequate cell-orchestrated modeling, trabecular bone tunes its mechanical properties by volume fraction and fabric. With proper calibration, these mechanical properties may be incorporated in quantitative CT-based finite element analysis that has been validated extensively with ex vivo experiments and has been applied increasingly in clinical trials to assess treatment efficacy against osteoporosis.

Evaluation of Angioarchitectural Features of Unruptured Brain Arteriovenous Malformation by Susceptibility Weighted Image (SWI).

PubMed

Wu, Chun-Xue; Ma, Li; Chen, Xu-Zhu; Chen, Xiao-Lin; Chen, Yu; Zhao, Yuan-Li; Hess, Christopher; Kim, Helen; Jin, Heng-Wei; Ma, Jun

2018-05-30

A precise assessment of angioarchitectural characteristics using non-invasive imaging is helpful for serial follow-up and weighting risk of natural history in uruptured brain arteriovenous malformation (bAVM). This study aimed to test the hypothesis that susceptibility weighted image (SWI) would provide an accurate evaluation of angioarchitectural features of unruptured bAVM.. A total of 81 consecutive patients with unruptured bAVM were examined. Image quality of SWI for the assessment of bAVM angioarchitectural features were determined by a five-point scale. The accuracy of SWI for detection of angioarchitectural features was evaluated using DSA as a standard reference. And further compared among unruptured bAVMs with or without silent intralesional microhemorrhage on SWI to examine the potential confounding effect of microhemorrhage on image analysis. All lesions were identified on SWI. Image quality of SWI was judged to be at least adequate for diagnosis (range, 3-5) in all patients by both readers. Using DSA as reference standard, the area under receiver operating curve (AUC) of detection of deep or posterior fossa location, exclusively deep venous drainage, venous ectasia, venous varices and the presence of associated aneurysm on SWI was 1, 0.93, 0.94, 0.95, and 0.83, respectively. Silent intralesional microhemorrhage were detected in 39 patients (48.15%) on SWI and no significant difference (P > 0.05) was found in angioarchitectural features between cases with and without silent microhemorrhage. SWI might be a non-invasive alternative technique for angiogram in the angioarchitectural assessment of unruptured bAVM. Copyright © 2018. Published by Elsevier Inc.

PKU-PET-II: A novel SiPM-based PET imaging system for small animals

NASA Astrophysics Data System (ADS)

Xie, Zhaoheng; Li, Suying; Zhou, Kun; Vuletic, Ivan; Meng, Xiangxi; Zhu, Sihao; Xu, Huan; Yang, Kun; Xu, Baixuan; Zhang, Jinming; Ren, Qiushi

2018-01-01

The objective of this study was to introduce, describe, and validate the performance of a novel preclinical silicon photomultiplier (SiPM)-based PET system (PKU-PET-II). Briefly, the detector assembly consisted of cerium-doped lutetium-yttrium oxyorthosilicate (LYSO) crystals, with dimensions of 2 ×2 ×15 mm3, that offered a 60 mm transaxial field of view (FOV) and 32 mm axial FOV, respectively. The compact front-end electronics readout and digital controller implemented architecture in the FPGA were noteworthy improvements in PKU-PET-II over its predecessor (PKU-PET-I). Based on the National Electrical Manufacturers Association (NEMA) NU 04-2008 standards, the design of the PKU-PET-II system was validated by a phantom experiment. The results presented spatial resolution (evaluated as full width at half maximum) with a system range from 1.68 ±0.07 to 2.31 ±0.03 mm at the FOV center and from 1.43 ±0.02 to 2.10 ±0.10 mm at the 1/4th axial FOV, respectively. The system's absolute sensitivity at the center position was 1.35% with the coincidence window of 6 ns and energy window of 300-700 keV. In addition, the NEMA image quality phantom and an animal study results validated the system imaging performance in preclinical imaging application. In conclusion, this SiPM-based, small-animal PET system (PKU-PET-II) provided higher-resolution, adequate sensitivity, and excellent image quality and has potential as a useful tool for real-time imaging of disease progression and development in vivo.

Tomotherapy as a tool in image-guided radiation therapy (IGRT): current clinical experience and outcomes

PubMed Central

Yartsev, S; Kron, T; Van Dyk, J

2007-01-01

Modern radiotherapy is characterised by a better target definition through medical imaging accompanied by significantly improved radiation delivery methods, most notably Intensity-Modulate Radiation Therapy (IMRT). However, the treatment can only be as accurate as the positioning of patients for their daily radiotherapy fraction. It is in this context that a number of imaging modalities - ranging from ultrasound to on-board kilovoltage imaging and computed tomography (CT) - have found their way into the treatment room where they verify accurate patient positioning prior to or even during delivery of radiation. Helical tomotherapy (HT) combines IMRT delivery with in-built image guidance using megavoltage CT scanning. This paper discusses the initial experience of different centres with IGRT using HT illustrated by a number of clinical examples from the installation in London in Ontario, Canada, one of the world’s first HT sites. We found that HT allows the delivery of highly conformal radiation dose distributions combined with adequate daily image acquisition. An important feature of this unit is its seamless integration, which also includes a customised inverse treatment planning system and a quality assurance module for individual patients. PMID:21614258

Quality of radiotherapy reporting in randomized controlled trials of prostate cancer.

PubMed

Soon, Yu Yang; Chen, Desiree; Tan, Teng Hwee; Tey, Jeremy

2018-06-07

Good radiotherapy reporting in clinical trials of prostate radiotherapy is important because it will allow accurate reproducibility of radiotherapy treatment and minimize treatment variations that can affect patient outcomes. The aim of our study is to assess the quality of prostate radiotherapy (RT) treatment reporting in randomized controlled trials in prostate cancer. We searched MEDLINE for randomized trials of prostate cancer, published from 1996 to 2016 and included prostate RT as one of the intervention arms. We assessed if the investigators reported the ten criteria adequately in the trial reports: RT dose prescription method; RT dose-planning procedures; organs at risk (OAR) dose constraints; target volume definition, simulation procedures; treatment verification procedures; total RT dose; fractionation schedule; conduct of quality assurance (QA) as well as presence or absence of deviations in RT treatment planning and delivery. We performed multivariate logistic regression to determine the factors that may influence the quality of reporting. We found 59 eligible trials. There was significant variability in the quality of reporting. Target volume definition, total RT dose and fractionation schedule were reported adequately in 97% of included trials. OAR constraints, simulation procedures and presence or absence of deviations in RT treatment planning and delivery were reported adequately in 30% of included trials. Twenty-four trials (40%) reported seven criteria or more adequately. Multivariable logistic analysis showed that trials that published their quality assurance results and cooperative group trials were more likely to have adequate quality in reporting in at least seven criteria. There is significant variability in the quality of reporting on prostate radiotherapy treatment in randomized trials of prostate cancer. We need to have consensus guidelines to standardize the reporting of radiotherapy treatment in randomized trials.

Methodological reporting of randomized clinical trials in respiratory research in 2010.

PubMed

Lu, Yi; Yao, Qiuju; Gu, Jie; Shen, Ce

2013-09-01

Although randomized controlled trials (RCTs) are considered the highest level of evidence, they are also subject to bias, due to a lack of adequately reported randomization, and therefore the reporting should be as explicit as possible for readers to determine the significance of the contents. We evaluated the methodological quality of RCTs in respiratory research in high ranking clinical journals, published in 2010. We assessed the methodological quality, including generation of the allocation sequence, allocation concealment, double-blinding, sample-size calculation, intention-to-treat analysis, flow diagrams, number of medical centers involved, diseases, funding sources, types of interventions, trial registration, number of times the papers have been cited, journal impact factor, journal type, and journal endorsement of the CONSORT (Consolidated Standards of Reporting Trials) rules, in RCTs published in 12 top ranking clinical respiratory journals and 5 top ranking general medical journals. We included 176 trials, of which 93 (53%) reported adequate generation of the allocation sequence, 66 (38%) reported adequate allocation concealment, 79 (45%) were double-blind, 123 (70%) reported adequate sample-size calculation, 88 (50%) reported intention-to-treat analysis, and 122 (69%) included a flow diagram. Multivariate logistic regression analysis revealed that journal impact factor ≥ 5 was the only variable that significantly influenced adequate allocation sequence generation. Trial registration and journal impact factor ≥ 5 significantly influenced adequate allocation concealment. Medical interventions, trial registration, and journal endorsement of the CONSORT statement influenced adequate double-blinding. Publication in one of the general medical journal influenced adequate sample-size calculation. The methodological quality of RCTs in respiratory research needs improvement. Stricter enforcement of the CONSORT statement should enhance the quality of RCTs.

Deformable Surface Accommodating Intraocular Lens: Second Generation Prototype Design Methodology and Testing.

PubMed

McCafferty, Sean J; Schwiegerling, Jim T

2015-04-01

Present an analysis methodology for developing and evaluating accommodating intraocular lenses incorporating a deformable interface. The next generation design of extruded gel interface intraocular lens is presented. A prototype based upon similar previously in vivo proven design was tested with measurements of actuation force, lens power, interface contour, optical transfer function, and visual Strehl ratio. Prototype verified mathematical models were used to optimize optical and mechanical design parameters to maximize the image quality and minimize the required force to accommodate. The prototype lens produced adequate image quality with the available physiologic accommodating force. The iterative mathematical modeling based upon the prototype yielded maximized optical and mechanical performance through maximum allowable gel thickness to extrusion diameter ratio, maximum feasible refractive index change at the interface, and minimum gel material properties in Poisson's ratio and Young's modulus. The design prototype performed well. It operated within the physiologic constraints of the human eye including the force available for full accommodative amplitude using the eye's natural focusing feedback, while maintaining image quality in the space available. The parameters that optimized optical and mechanical performance were delineated as those, which minimize both asphericity and actuation pressure. The design parameters outlined herein can be used as a template to maximize the performance of a deformable interface intraocular lens. The article combines a multidisciplinary basic science approach from biomechanics, optical science, and ophthalmology to optimize an intraocular lens design suitable for preliminary animal trials.

The almost-invisible perineurioma.

PubMed

Restrepo, Carlos E; Amrami, Kimberly K; Howe, Benjamin M; Dyck, P James B; Mauermann, Michelle L; Spinner, Robert J

2015-09-01

Intraneural perineurioma is a rare, benign slow-growing lesion arising from the perineurial cells that surrounds the peripheral nerve fibers. Typically it presents during childhood and young adulthood as a motor mononeuropathy. MRI plays an essential role in the diagnosis and localization of the lesion, which appears as a fusiform enlargement of the nerve fascicles that enhances intensely with gadolinium. Despite the typical clinical and radiological features, intraneural perineurioma remains largely underdiagnosed because of the lack of familiarity with this entity, but also as a result of technical limitations with conventional MRI that is typically performed as a screening test over a large field of view and without contrast sequences. The purpose of this article is to present the pitfalls and pearls learned from years of experience in the diagnosis and management of this relatively rare condition. Clinical suspicion and detailed neurological examination followed by high-quality electrophysiological studies (EPS) must lead to an adequate preimaging localization of the lesion and narrowing of the imaging area. The use of high-resolution (3-T) MRI combined with gadolinium administration will allow adequate visualization of the internal anatomy of the nerve and help in differentiating other causes of neuropathy. In cases where the lesion is not recognized but clinical suspicion is high, possible errors must be assessed, including the EPS localization, area of imaging, MRI resolution, and slice thickness.

How does c-view image quality compare with conventional 2D FFDM?

PubMed

Nelson, Jeffrey S; Wells, Jered R; Baker, Jay A; Samei, Ehsan

2016-05-01

The FDA approved the use of digital breast tomosynthesis (DBT) in 2011 as an adjunct to 2D full field digital mammography (FFDM) with the constraint that all DBT acquisitions must be paired with a 2D image to assure adequate interpretative information is provided. Recently manufacturers have developed methods to provide a synthesized 2D image generated from the DBT data with the hope of sparing patients the radiation exposure from the FFDM acquisition. While this much needed alternative effectively reduces the total radiation burden, differences in image quality must also be considered. The goal of this study was to compare the intrinsic image quality of synthesized 2D c-view and 2D FFDM images in terms of resolution, contrast, and noise. Two phantoms were utilized in this study: the American College of Radiology mammography accreditation phantom (ACR phantom) and a novel 3D printed anthropomorphic breast phantom. Both phantoms were imaged using a Hologic Selenia Dimensions 3D system. Analysis of the ACR phantom includes both visual inspection and objective automated analysis using in-house software. Analysis of the 3D anthropomorphic phantom includes visual assessment of resolution and Fourier analysis of the noise. Using ACR-defined scoring criteria for the ACR phantom, the FFDM images scored statistically higher than c-view according to both the average observer and automated scores. In addition, between 50% and 70% of c-view images failed to meet the nominal minimum ACR accreditation requirements-primarily due to fiber breaks. Software analysis demonstrated that c-view provided enhanced visualization of medium and large microcalcification objects; however, the benefits diminished for smaller high contrast objects and all low contrast objects. Visual analysis of the anthropomorphic phantom showed a measureable loss of resolution in the c-view image (11 lp/mm FFDM, 5 lp/mm c-view) and loss in detection of small microcalcification objects. Spectral analysis of the anthropomorphic phantom showed higher total noise magnitude in the FFDM image compared with c-view. Whereas the FFDM image contained approximately white noise texture, the c-view image exhibited marked noise reduction at midfrequency and high frequency with far less noise suppression at low frequencies resulting in a mottled noise appearance. Their analysis demonstrates many instances where the c-view image quality differs from FFDM. Compared to FFDM, c-view offers a better depiction of objects of certain size and contrast, but provides poorer overall resolution and noise properties. Based on these findings, the utilization of c-view images in the clinical setting requires careful consideration, especially if considering the discontinuation of FFDM imaging. Not explicitly explored in this study is how the combination of DBT + c-view performs relative to DBT + FFDM or FFDM alone.

Design Information for Emergency Operations Centers.

DTIC Science & Technology

1983-06-01

STC 40-45 4. Visual privacy. Sound Reflectances: 5. Electrical survey. Ceiling: NRC 50 6. Adequate lighting. Floor: NRC 25 7. Adequate thermal comfort . 4...ceiling to 7. Adequate thermal comfort . reduce noise. 8. Image appropriate for authority 4. 60-in.-high minimum wall panels. given. 5. 110-V outlets as...tions. 5. Electrical supply. 2. 9-ft minimum for open plan office 6. Adequate lighting, schemes. 7. Adequate thermal comfort . 3. Enclosing walls: STC 40

Frequency band justifications for passive sensors, 1 to 10 GHz. [for monitoring earth resources and the environment

NASA Technical Reports Server (NTRS)

1976-01-01

Remote sensor systems operating in the microwave region of the frequency spectrum provide information unobtainable with basic imaging techniques such as photography, television, or multispectral imaging. The frequency allocation requirements for passive microwave sensors used in the earth exploration satellite and space research services are presented for: (1) agriculture, forestry, and range resources; (2) land use survey and mapping: (3) water resources; (4) weather and climate; (5) environmental quality; and (6) marine resources, estuarine and oceans. Because measurements are required simultaneously in multiple frequency bands to adequately determine values of some phenomena, the relationships between frequency bands are discussed. The various measurement accuracies, dynamic range, resolutions and frequency needs are examined. A band-by-band summary of requirements, unique aspects, and sharing analyses of the required frequency bands is included.

Battling fire and ice: remote guidance ultrasound to diagnose injury on the International Space Station and the ice rink.

PubMed

Kwon, David; Bouffard, J Antonio; van Holsbeeck, Marnix; Sargsyan, Asot E; Hamilton, Douglas R; Melton, Shannon L; Dulchavsky, Scott A

2007-03-01

National Aeronautical and Space and Administration (NASA) researchers have optimized training methods that allow minimally trained, non-physician operators to obtain diagnostic ultrasound (US) images for medical diagnosis including musculoskeletal injury. We hypothesize that these techniques could be expanded to non-expert operators including National Hockey League (NHL) and Olympic athletic trainers to diagnose musculoskeletal injuries in athletes. NHL and Olympic athletic trainers received a brief course on musculoskeletal US. Remote guidance musculoskeletal examinations were conducted by athletic trainers, consisting of hockey groin hernia, knee, ankle, elbow, or shoulder evaluations. US images were transmitted to remote experts for interpretation. Groin, knee, ankle, elbow, or shoulder images were obtained on 32 athletes; all real-time US video stream and still capture images were considered adequate for diagnostic interpretation. This experience suggests that US can be expanded for use in locations without a high level of on-site expertise. A non-physician with minimal training can perform complex, diagnostic-quality examinations when directed by a remote-based expert.

Practical low-cost visual communication using binary images for deaf sign language.

PubMed

Manoranjan, M D; Robinson, J A

2000-03-01

Deaf sign language transmitted by video requires a temporal resolution of 8 to 10 frames/s for effective communication. Conventional videoconferencing applications, when operated over low bandwidth telephone lines, provide very low temporal resolution of pictures, of the order of less than a frame per second, resulting in jerky movement of objects. This paper presents a practical solution for sign language communication, offering adequate temporal resolution of images using moving binary sketches or cartoons, implemented on standard personal computer hardware with low-cost cameras and communicating over telephone lines. To extract cartoon points an efficient feature extraction algorithm adaptive to the global statistics of the image is proposed. To improve the subjective quality of the binary images, irreversible preprocessing techniques, such as isolated point removal and predictive filtering, are used. A simple, efficient and fast recursive temporal prefiltering scheme, using histograms of successive frames, reduces the additive and multiplicative noise from low-cost cameras. An efficient three-dimensional (3-D) compression scheme codes the binary sketches. Subjective tests performed on the system confirm that it can be used for sign language communication over telephone lines.

Multimodality Imaging in Cardiooncology

PubMed Central

Pizzino, Fausto; Vizzari, Giampiero; Qamar, Rubina; Bomzer, Charles; Carerj, Scipione; Khandheria, Bijoy K.

2015-01-01

Cardiotoxicity represents a rising problem influencing prognosis and quality of life of chemotherapy-treated patients. Anthracyclines and trastuzumab are the drugs most commonly associated with development of a cardiotoxic effect. Heart failure, myocardial ischemia, hypertension, myocarditis, and thrombosis are typical manifestation of cardiotoxicity by chemotherapeutic agents. Diagnosis and monitoring of cardiac side-effects of cancer treatment is of paramount importance. Echocardiography and nuclear medicine methods are widely used in clinical practice and left ventricular ejection fraction is the most important parameter to asses myocardial damage secondary to chemotherapy. However, left ventricular ejection decrease is a delayed phenomenon, occurring after a long stage of silent myocardial damage that classic imaging methods are not able to detect. New imaging techniques including three-dimensional echocardiography, speckle tracking echocardiography, and cardiac magnetic resonance have demonstrated high sensitivity in detecting the earliest alteration of left ventricular function associated with future development of chemotherapy-induced cardiomyopathy. Early diagnosis of cardiac involvement in cancer patients can allow for timely and adequate treatment management and the introduction of cardioprotective strategies. PMID:26300915

Comparative evaluation of image quality among different detector configurations using area detector computed tomography.

PubMed

Miura, Yohei; Ichikawa, Katsuhiro; Fujimura, Ichiro; Hara, Takanori; Hoshino, Takashi; Niwa, Shinji; Funahashi, Masao

2018-03-01

The 320-detector row computed tomography (CT) system, i.e., the area detector CT (ADCT), can perform helical scanning with detector configurations of 4-, 16-, 32-, 64-, 80-, 100-, and 160-detector rows for routine CT examinations. This phantom study aimed to compare the quality of images obtained using helical scan mode with different detector configurations. The image quality was measured using modulation transfer function (MTF) and noise power spectrum (NPS). The system performance function (SP), based on the pre-whitening theorem, was calculated as MTF 2 /NPS, and compared between configurations. Five detector configurations, i.e., 0.5 × 16 mm (16 row), 0.5 × 64 mm (64 row), 0.5 × 80 mm (80 row), 0.5 × 100 mm (100 row), and 0.5 × 160 mm (160 row), were compared using a constant volume CT dose index (CTDI vol ) of 25 mGy, simulating the scan of an adult abdomen, and with a constant effective mAs value. The MTF was measured using the wire method, and the NPS was measured from images of a 20-cm diameter phantom with uniform content. The SP of 80-row configuration was the best, for the constant CTDI vol , followed by the 64-, 160-, 16-, and 100-row configurations. The decrease in the rate of the 100- and 160-row configurations from the 80-row configuration was approximately 30%. For the constant effective mAs, the SPs of the 100-row and 160-row configurations were significantly lower, compared with the other three detector configurations. The 80- and 64-row configurations were adequate in cases that required dose efficiency rather than scan speed.

iPhone 4s and iPhone 5s Imaging of the Eye

PubMed Central

Jalil, Maaz; Ferenczy, Sandor R.; Shields, Carol L.

2017-01-01

Background/Aims To evaluate the technical feasibility of a consumer-grade cellular iPhone camera as an ocular imaging device compared to existing ophthalmic imaging equipment for documentation purposes. Methods A comparison of iPhone 4s and 5s images was made with external facial images (macrophotography) using Nikon cameras, slit-lamp images (microphotography) using Zeiss photo slit-lamp camera, and fundus images (fundus photography) using RetCam II. Results In an analysis of six consecutive patients with ophthalmic conditions, both iPhones achieved documentation of external findings (macrophotography) using standard camera modality, tap to focus, and built-in flash. Both iPhones achieved documentation of anterior segment findings (microphotography) during slit-lamp examination through oculars. Both iPhones achieved fundus imaging using standard video modality with continuous iPhone illumination through an ophthalmic lens. Comparison to standard ophthalmic cameras, macrophotography and microphotography were excellent. In comparison to RetCam fundus photography, iPhone fundus photography revealed smaller field and was technically more difficult to obtain, but the quality was nearly similar to RetCam. Conclusions iPhone versions 4s and 5s can provide excellent ophthalmic macrophotography and microphotography and adequate fundus photography. We believe that iPhone imaging could be most useful in settings where expensive, complicated, and cumbersome imaging equipment is unavailable. PMID:28275604

Evaluation and Referral of Diabetic Eye Disease in the Endocrinology and Primary Care Office Settings.

PubMed

Silva, Fabiana Q; Adhi, Mehreen; Wai, Karen M; Olansky, Leann; Lansang, M Cecilia; Singh, Rishi P

2016-10-01

The purpose of this study was to identify whether endocrinologists and primary care physicians (PCP) adequately screen for ophthalmic symptoms/signs within office visits and provide timely ophthalmology referrals in patients with diabetes. Patients between the ages of 18 years and 80 years with diabetes who underwent an office visit with an endocrinologist or a PCP between January 1, 2014, and December 31, 2014, were identified. Demographics, ophthalmic assessments, and referral information were collected. A total of 1,250 patient records were reviewed. Providers asked about ophthalmic symptoms/signs in 95.5% and 71% of endocrinology and primary care office encounters, respectively (P < .0001). Past and/or future ophthalmology appointments were verified in 86.1% and 49.7% of patients during endocrinology and PCP visits, respectively (P < .0001). Ophthalmic complications from diabetes are not adequately screened, especially within the primary care setting, and further quality improvement measures may improve adherence to recommended screening protocols. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:930-934.]. Copyright 2016, SLACK Incorporated.

Nonprofit to for-profit conversions by hospitals, health insurers, and health plans.

PubMed Central

Needleman, J

1999-01-01

Conversion of hospitals, health insurers, and health plans from nonprofit to for-profit ownership has become a focus of national debate. The author examines why nonprofit ownership has been dominant in the US health system and assesses the strength of the argument that nonprofits provide community benefits that would be threatened by for-profit conversion. The author concludes that many of the specific community benefits offered by nonprofits, such as care for the poor, could be maintained or replaced by adequate funding of public programs and that quality and fairness in treatment can be better assured through clear standards of care and adequate monitoring systems. As health care becomes increasingly commercialized, the most difficult parts of nonprofits' historic mission to preserve are the community orientation, leadership role, and innovation that nonprofit hospitals and health plans have provided out of their commitment to a community beyond those to whom they sell services. Images p109-a p110-a p115-a p116-a PMID:10199712

SU-E-J-38: Improved DRR Image Quality Using Polyetheretherketone (PEEK) Fiducial in Image Guided Radiotherapy (IGRT)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, S; Jacob, R; Popple, R

Purpose Fiducial-based imaging is often used in IGRT. Traditional gold fiducial marker often has substantial reconstruction artifacts. These artifacts Result in poor image quality of DRR for online kV-to-DRR matching. This study evaluated the image quality of PEEK in DRR in static and moving phantom. Methods CT scan of the Gold and PEEK fiducial (both 1×3 mm) was acquired in a 22 cm cylindrical phantom filled with water. Image artifacts was evaluated with maximum CT value deviated from water due to artifacts; volume of artifacts in 10×10 cm in the center slice; maximum length of streak artifacts from the fiducial.more » DRR resolution were measured using FWHM and FWTM. 4DCT of PEEK fiducial was acquired with the phantom moving sinusoidally in superior-inferior direction. Motion artifacts were assessed for various 4D phase angles. Results The maximum CT value deviation was −174 for Gold and −24 for PEEK. The volume of artifacts in a 10x10 cm 3 mm slice was 0.369 for Gold and 0.074 cm3 for PEEK. The maximum length of streak artifact was 80mm for Gold and 7 mm for PEEK. PEEK in DRR, FWHM was close to actual (1.0 mm for Gold and 1.1 mm for PEEK). FWTM was 1.8 mm for Gold and 1.3 mm for PEEK in DRR. Barrel motion artifact of PEEK fiducial was noticeable for free-breathing scan. The apparent PEEK length due to residual motion was in close agreement with the calculated length (13 mm for 30–70 phase, 10 mm in 40–60 phase). Conclusion Streak artifacts on planning CT associated with use of gold fiducial can be significantly reduced by PEEK fiducial, while having adequate kV image contrast. DRR image resolution at FWTM was improved from 1.8 mm to 1.3 mm. Because of this improvement, we have been routinely use PEEK for liver IGRT.« less

Commissioning and quality assurance of an integrated system for patient positioning and setup verification in particle therapy.

PubMed

Pella, A; Riboldi, M; Tagaste, B; Bianculli, D; Desplanques, M; Fontana, G; Cerveri, P; Seregni, M; Fattori, G; Orecchia, R; Baroni, G

2014-08-01

In an increasing number of clinical indications, radiotherapy with accelerated particles shows relevant advantages when compared with high energy X-ray irradiation. However, due to the finite range of ions, particle therapy can be severely compromised by setup errors and geometric uncertainties. The purpose of this work is to describe the commissioning and the design of the quality assurance procedures for patient positioning and setup verification systems at the Italian National Center for Oncological Hadrontherapy (CNAO). The accuracy of systems installed in CNAO and devoted to patient positioning and setup verification have been assessed using a laser tracking device. The accuracy in calibration and image based setup verification relying on in room X-ray imaging system was also quantified. Quality assurance tests to check the integration among all patient setup systems were designed, and records of daily QA tests since the start of clinical operation (2011) are presented. The overall accuracy of the patient positioning system and the patient verification system motion was proved to be below 0.5 mm under all the examined conditions, with median values below the 0.3 mm threshold. Image based registration in phantom studies exhibited sub-millimetric accuracy in setup verification at both cranial and extra-cranial sites. The calibration residuals of the OTS were found consistent with the expectations, with peak values below 0.3 mm. Quality assurance tests, daily performed before clinical operation, confirm adequate integration and sub-millimetric setup accuracy. Robotic patient positioning was successfully integrated with optical tracking and stereoscopic X-ray verification for patient setup in particle therapy. Sub-millimetric setup accuracy was achieved and consistently verified in daily clinical operation.

Concept of a selective tumour therapy and its evaluation by near-infrared fluorescence imaging and flat-panel volume computed tomography in mice.

PubMed

Alves, Frauke; Dullin, Christian; Napp, Joanna; Missbach-Guentner, Jeannine; Jannasch, Katharina; Mathejczyk, Julia; Pardo, Luis A; Stühmer, Walter; Tietze, Lutz-F

2009-05-01

Conventional chemotherapy of cancer has its limitations, especially in advanced and disseminated disease and suffers from lack of specificity. This results in a poor therapeutic index and considerable toxicity to normal organs. Therefore, many efforts are made to develop novel therapeutic tools against cancer with the aim of selectively targeting the drug to the tumour site. Drug delivery strategies fundamentally rely on the identification of good-quality biomarkers, allowing unequivocal discrimination between cancer and healthy tissue. At present, antibodies or antibody fragments have clearly proven their value as carrier molecules specific for a tumour-associated molecular marker. This present review draws attention to the use of near-infrared fluorescence (NIRF) imaging to investigate binding specificity and kinetics of carrier molecules such as monoclonal antibodies. In addition, flat-panel volume computed tomography (fpVCT) will be presented to monitor anatomical structures in tumour mouse models over time in a non-invasive manner. Each imaging device sheds light on a different aspect; functional imaging is applied to optimise the dose schedule and the concept of selective tumour therapies, whereas anatomical imaging assesses preclinically the efficacy of novel tumour therapies. Both imaging techniques in combination allow the visualisation of functional information obtained by NIRF imaging within an adequate anatomic framework.

Organoleptic damage classification of potatoes with the use of image analysis in production process

NASA Astrophysics Data System (ADS)

Przybył, K.; Zaborowicz, M.; Koszela, K.; Boniecki, P.; Mueller, W.; Raba, B.; Lewicki, A.

2014-04-01

In the agro-food sector security it is required the safety of a healthy food. Therefore, the farms are inspected by the quality standards of production in all sectors of production. Farms must meet the requirements dictated by the legal regulations in force in the European Union. Currently, manufacturers are seeking to make their food products have become unbeatable. This gives you the chance to form their own brand on the market. In addition, they use technologies that can increase the scale of production. Moreover, in the manufacturing process they tend to maintain a high level of quality of their products. Potatoes may be included in this group of agricultural products. Potatoes have become one of the major and popular edible plants. Globally, potatoes are used for consumption at 60%, Poland 40%. This is due to primarily advantages, consumer and nutritional qualities. Potatoes are easy to digest. Medium sized potato bigger than 60 mm in diameter contains only about 60 calories and very little fat. Moreover, it is the source of many vitamins such as vitamin C, vitamin B1, vitamin B2, vitamin E, etc. [1]. The parameters of quality consumer form, called organoleptic sensory properties, are evaluated by means of sensory organs by using the point method. The most important are: flavor, flesh color, darkening of the tuber flesh when raw and after cooking. In the production process it is important to adequate, relevant and accurate preparing potatoes for use and sale. Evaluation of the quality of potatoes is determined on the basis of organoleptic quality standards for potatoes. Therefore, there is a need to automate this process. To do this, use the appropriate tools, image analysis and classification models using artificial neural networks that will help assess the quality of potatoes [2, 3, 4].

Reduced bone mineral density is not associated with significantly reduced bone quality in men and women practicing long-term calorie restriction with adequate nutrition.

PubMed

Villareal, Dennis T; Kotyk, John J; Armamento-Villareal, Reina C; Kenguva, Venkata; Seaman, Pamela; Shahar, Allon; Wald, Michael J; Kleerekoper, Michael; Fontana, Luigi

2011-02-01

Calorie restriction (CR) reduces bone quantity but not bone quality in rodents. Nothing is known regarding the long-term effects of CR with adequate intake of vitamin and minerals on bone quantity and quality in middle-aged lean individuals. In this study, we evaluated body composition, bone mineral density (BMD), and serum markers of bone turnover and inflammation in 32 volunteers who had been eating a CR diet (approximately 35% less calories than controls) for an average of 6.8 ± 5.2 years (mean age 52.7 ± 10.3 years) and 32 age- and sex-matched sedentary controls eating Western diets (WD). In a subgroup of 10 CR and 10 WD volunteers, we also measured trabecular bone (TB) microarchitecture of the distal radius using high-resolution magnetic resonance imaging. We found that the CR volunteers had significantly lower body mass index than the WD volunteers (18.9 ± 1.2 vs. 26.5 ± 2.2 kg m(-2) ; P = 0.0001). BMD of the lumbar spine (0.870 ± 0.11 vs. 1.138 ± 0.12 g cm(-2) , P = 0.0001) and hip (0.806 ± 0.12 vs. 1.047 ± 0.12 g cm(-2) , P = 0.0001) was also lower in the CR than in the WD group. Serum C-terminal telopeptide and bone-specific alkaline phosphatase concentration were similar between groups, while serum C-reactive protein (0.19 ± 0.26 vs. 1.46 ± 1.56 mg L(-1) , P = 0.0001) was lower in the CR group. Trabecular bone microarchitecture parameters such as the erosion index (0.916 ± 0.087 vs. 0.877 ± 0.088; P = 0.739) and surface-to-curve ratio (10.3 ± 1.4 vs. 12.1 ± 2.1, P = 0.440) were not significantly different between groups. These findings suggest that markedly reduced BMD is not associated with significantly reduced bone quality in middle-aged men and women practicing long-term calorie restriction with adequate nutrition.

Implementation of Size-Dependent Local Diagnostic Reference Levels for CT Angiography.

PubMed

Boere, Hub; Eijsvoogel, Nienke G; Sailer, Anna M; Wildberger, Joachim E; de Haan, Michiel W; Das, Marco; Jeukens, Cecile R L P N

2018-05-01

Diagnostic reference levels (DRLs) are established for standard-sized patients; however, patient dose in CT depends on patient size. The purpose of this study was to introduce a method for setting size-dependent local diagnostic reference levels (LDRLs) and to evaluate these LDRLs in comparison with size-independent LDRLs and with respect to image quality. One hundred eighty-four aortic CT angiography (CTA) examinations performed on either a second-generation or third-generation dual-source CT scanner were included; we refer to the second-generation dual-source CT scanner as "CT1" and the third-generation dual-source CT scanner as "CT2." The volume CT dose index (CTDI vol ) and patient diameter (i.e., the water-equivalent diameter) were retrieved by dose-monitoring software. Size-dependent DRLs based on a linear regression of the CTDI vol versus patient size were set by scanner type. Size-independent DRLs were set by the 5th and 95th percentiles of the CTDI vol values. Objective image quality was assessed using the signal-to-noise ratio (SNR), and subjective image quality was assessed using a 4-point Likert scale. The CTDI vol depended on patient size and scanner type (R 2 = 0.72 and 0.78, respectively; slope = 0.05 and 0.02 mGy/mm; p < 0.001). Of the outliers identified by size-independent DRLs, 30% (CT1) and 67% (CT2) were adequately dosed when considering patient size. Alternatively, 30% (CT1) and 70% (CT2) of the outliers found with size-dependent DRLs were not identified using size-independent DRLs. A negative correlation was found between SNR and CTDI vol (R 2 = 0.36 for CT1 and 0.45 for CT2). However, all outliers had a subjective image quality score of sufficient or better. We introduce a method for setting size-dependent LDRLs in CTA. Size-dependent LDRLs are relevant for assessing the appropriateness of the radiation dose for an individual patient on a specific CT scanner.

A Protocol to Preserve the Integrity of Stable Fly (Diptera: Muscidae) DNA for Long Distance Shipment

USDA-ARS?s Scientific Manuscript database

Population genetic studies on a global scale may be hampered by the ability to acquire quality samples from distant countries. Preservation methods must be adequate to prevent the samples from decay during shipping, so an adequate quantity of quality DNA can be extracted for analysis, and materials...

The Relationship between Adequate Yearly Progress and the Quality of Professional Development

ERIC Educational Resources Information Center

Wolff, Lori A.; McClelland, Susan S.; Stewart, Stephanie E.

2010-01-01

Based on publicly available data, the study examined the relationship between adequate yearly progress status and teachers' perceptions of the quality of their professional development. The sample included responses of 5,558 teachers who completed the questionnaire in the 2005-2006 school year. Results of the statistical analysis show a…

Scalable splitting algorithms for big-data interferometric imaging in the SKA era

NASA Astrophysics Data System (ADS)

Onose, Alexandru; Carrillo, Rafael E.; Repetti, Audrey; McEwen, Jason D.; Thiran, Jean-Philippe; Pesquet, Jean-Christophe; Wiaux, Yves

2016-11-01

In the context of next-generation radio telescopes, like the Square Kilometre Array (SKA), the efficient processing of large-scale data sets is extremely important. Convex optimization tasks under the compressive sensing framework have recently emerged and provide both enhanced image reconstruction quality and scalability to increasingly larger data sets. We focus herein mainly on scalability and propose two new convex optimization algorithmic structures able to solve the convex optimization tasks arising in radio-interferometric imaging. They rely on proximal splitting and forward-backward iterations and can be seen, by analogy, with the CLEAN major-minor cycle, as running sophisticated CLEAN-like iterations in parallel in multiple data, prior, and image spaces. Both methods support any convex regularization function, in particular, the well-studied ℓ1 priors promoting image sparsity in an adequate domain. Tailored for big-data, they employ parallel and distributed computations to achieve scalability, in terms of memory and computational requirements. One of them also exploits randomization, over data blocks at each iteration, offering further flexibility. We present simulation results showing the feasibility of the proposed methods as well as their advantages compared to state-of-the-art algorithmic solvers. Our MATLAB code is available online on GitHub.

Reciprocal effects among changes in weight, body image, and other psychological factors during behavioral obesity treatment: a mediation analysis.

PubMed

Palmeira, António L; Markland, David A; Silva, Marlene N; Branco, Teresa L; Martins, Sandra C; Minderico, Cláudia S; Vieira, Paulo N; Barata, José T; Serpa, Sidónio O; Sardinha, Luis B; Teixeira, Pedro J

2009-02-09

Changes in body image and subjective well-being variables (e.g. self-esteem) are often reported as outcomes of obesity treatment. However, they may, in turn, also influence behavioral adherence and success in weight loss. The present study examined associations among obesity treatment-related variables, i.e., change in weight, quality of life, body image, and subjective well-being, exploring their role as both mediators and outcomes, during a behavioral obesity treatment. Participants (BMI = 31.1 +/- 4.1 kg/m2; age = 38.4 +/- 6.7 y) were 144 women who attended a 12-month obesity treatment program and a comparison group (n = 49), who received a general health education program. The intervention included regular group meetings promoting lasting behavior changes in physical activity and dietary intake. Body image, quality of life, subjective well-being, and body weight were measured at baseline and treatment's end. Mediation was tested by multiple regression and a resampling approach to measure indirect effects. Treatment group assignment was the independent variable while changes in weight and in psychosocial variables were analyzed alternatively as mediators and as dependent variables. At 12 months, the intervention group had greater weight loss (-5.6 +/- 6.8% vs. -1.2 +/- 4.6%, p < .001) and larger decreases in body size dissatisfaction (effect size of 1.08 vs. .41, p < .001) than the comparison group. Significant improvements were observed in both groups for all other psychosocial variables (effect sizes ranging from .31-.75, p < .05). Mediation analysis showed that changes in body image and body weight were concurrently mediators and outcomes of treatment, suggesting reciprocal influences. Weight loss partially mediated the effect of treatment on quality of life and on self-esteem but the reciprocal effect was not observed. Changes in weight and body image may reciprocally affect each other during the course of behavioral obesity treatment. No evidence of reciprocal relationships was found for the other models under analysis; however, weight changes partially explained the effects of treatment on quality of life and self-esteem. Weight and psychosocial changes co-occur during treatment and will probably influence each other dynamically, in ways not yet adequately understood. Results from this study support the inclusion of intervention contents aimed at improving body image in weight management programs.

Contralateral decubitus positioning enhances computed tomographic angiographic evaluation of pulmonary vasculature in a patient with a pulmonary arteriovenous malformation.

PubMed

Tafti, Bashir Akhavan; Berenji, Gholam R; Santiago, Silverio; Barack, Bruce M

2012-11-01

Computed tomographic pulmonary angiography has become the diagnostic procedure of choice in patients suspected of having a pulmonary embolus. However, intrapulmonary shunting of blood in a variety of pathologic conditions can cause suboptimal opacification of the pulmonary arterial circulation and result in a suboptimal or even nondiagnostic study. Radiologists should be aware of these conditions and be familiar with positioning techniques to minimize such shunting. We report a patient suspected of having pulmonary embolism, in whom a preexisting unilateral arteriovenous malformation prevented adequate evaluation of the pulmonary circulation. Positioning the patient in the contralateral decubitus position significantly enhanced image quality.

Recognizable-image selection for fingerprint recognition with a mobile-device camera.

PubMed

Lee, Dongjae; Choi, Kyoungtaek; Choi, Heeseung; Kim, Jaihie

2008-02-01

This paper proposes a recognizable-image selection algorithm for fingerprint-verification systems that use a camera embedded in a mobile device. A recognizable image is defined as the fingerprint image which includes the characteristics that are sufficiently discriminating an individual from other people. While general camera systems obtain focused images by using various gradient measures to estimate high-frequency components, mobile cameras cannot acquire recognizable images in the same way because the obtained images may not be adequate for fingerprint recognition, even if they are properly focused. A recognizable image has to meet the following two conditions: First, valid region in the recognizable image should be large enough compared with other nonrecognizable images. Here, a valid region is a well-focused part, and ridges in the region are clearly distinguishable from valleys. In order to select valid regions, this paper proposes a new focus-measurement algorithm using the secondary partial derivatives and a quality estimation utilizing the coherence and symmetry of gradient distribution. Second, rolling and pitching degrees of a finger measured from the camera plane should be within some limit for a recognizable image. The position of a core point and the contour of a finger are used to estimate the degrees of rolling and pitching. Experimental results show that our proposed method selects valid regions and estimates the degrees of rolling and pitching properly. In addition, fingerprint-verification performance is improved by detecting the recognizable images.

Atlas-based head modeling and spatial normalization for high-density diffuse optical tomography: in vivo validation against fMRI.

PubMed

Ferradal, Silvina L; Eggebrecht, Adam T; Hassanpour, Mahlega; Snyder, Abraham Z; Culver, Joseph P

2014-01-15

Diffuse optical imaging (DOI) is increasingly becoming a valuable neuroimaging tool when fMRI is precluded. Recent developments in high-density diffuse optical tomography (HD-DOT) overcome previous limitations of sparse DOI systems, providing improved image quality and brain specificity. These improvements in instrumentation prompt the need for advancements in both i) realistic forward light modeling for accurate HD-DOT image reconstruction, and ii) spatial normalization for voxel-wise comparisons across subjects. Individualized forward light models derived from subject-specific anatomical images provide the optimal inverse solutions, but such modeling may not be feasible in all situations. In the absence of subject-specific anatomical images, atlas-based head models registered to the subject's head using cranial fiducials provide an alternative solution. In addition, a standard atlas is attractive because it defines a common coordinate space in which to compare results across subjects. The question therefore arises as to whether atlas-based forward light modeling ensures adequate HD-DOT image quality at the individual and group level. Herein, we demonstrate the feasibility of using atlas-based forward light modeling and spatial normalization methods. Both techniques are validated using subject-matched HD-DOT and fMRI data sets for visual evoked responses measured in five healthy adult subjects. HD-DOT reconstructions obtained with the registered atlas anatomy (i.e. atlas DOT) had an average localization error of 2.7mm relative to reconstructions obtained with the subject-specific anatomical images (i.e. subject-MRI DOT), and 6.6mm relative to fMRI data. At the group level, the localization error of atlas DOT reconstruction was 4.2mm relative to subject-MRI DOT reconstruction, and 6.1mm relative to fMRI. These results show that atlas-based image reconstruction provides a viable approach to individual head modeling for HD-DOT when anatomical imaging is not available. Copyright © 2013. Published by Elsevier Inc.

Testing a dual-modality system that combines full-field digital mammography and automated breast ultrasound

PubMed Central

Vaughan, Christopher L; Douglas, Tania S; Said-Hartley, Qonita; Baasch, Roland V; Boonzaier, James A; Goemans, Brian C; Harverson, John; Mingay, Michael W; Omar, Shuaib; Smith, Raphael V; Venter, Nielen C; Wilson, Heidi S

2015-01-01

Purpose The aim of this study was to test a novel dual-modality imaging system that combines full-field digital mammography (FFDM) and automated breast ultrasound (ABUS) in a single platform. Our Aceso system, named after the Greek goddess of healing, was specifically designed for the early detection of cancer in women with dense breast tissue. Materials and Methods Aceso was first tested using two industry standards: a CDMAM phantom as endorsed by EUREF was used to assess the FFDM images; and the CIRS 040GSE ultrasound phantom was imaged to evaluate the quality of the ABUS images. In addition, 58 women participated in a clinical trial: 51 were healthy volunteers aged between 40 and 65, while 7 were patients referred by the breast clinic, 6 of whom had biopsy-proven breast cancer. Results The CDMAM tests showed that the FFDM results were “acceptable” but fell short of “achievable” which was attributed to the low dose used. The ABUS images had good depth penetration (80 mm) and adequate axial resolution (0.5 mm) but the lateral resolution of 2 mm was judged to be too coarse. In a 42-year old volunteer with extremely dense breast tissue, the ABUS modality detected a lesion (a benign cyst) that was mammographically occult in the FFDM image. For a 73-year old patient with fatty breasts, a malignant lesion was successfully detected and co-registered in the FFDM and ABUS images. On average, each woman spent less than 11 minutes in the acquisition room. Conclusions While there is room for improvement in the quality of both the FFDM and ABUS images, Aceso has demonstrated its ability to acquire clinically meaningful images for a range of women with varying breast densities and therefore has potential as a screening device. PMID:27133694

Inadequate pelvic radiographs: implications of not getting it right the first time.

PubMed

Parker, S; Nagra, N S; Kulkarni, K; Pegrum, J; Barry, S; Hughes, R; Ghani, Y

2017-09-01

Introduction Pelvic radiography is a frequent investigation. European guidelines aim to ensure appropriate use and adequate quality. When initial images are inadequate, repeat radiographs are often required, which may have significant patient safety and economic implications. Objectives The study aimed to assess the adequacy of pelvic imaging across three orthopaedic centres, to identify causes for inadequate imaging and to establish the cost of inadequate imaging from financial and patient safety perspectives. Methods Pelvic radiographs were identified on Picture Archiving and Communication System software at three UK hospitals. Radiographs were assessed against European guidelines and indications for repeat imaging were analysed. Results A total of 1,531 sequential pelvic radiographs were reviewed. The mean age of patients was 60 years (range 5 months to 101 years). Of this total, 51.9% of images were suboptimal, with no significant difference across the three hospitals (P > 0.05). Hospital 3 repeated radiographs in 6.3% of cases, compare with 18.1% and 19.7% at hospitals 1 and 2, respectively (P > 0.05). Hospital 3 identified pathology missed on the initial radiograph in 1% of cases, compared with 5.4% and 5.5% at hospitals 1 and 2, respectively (P > 0.05). Out-of-hours imaging is associated with a higher rate of suboptimal quality (69.1%) compared with normal working hours (51.3%; P = 0.006). Adequacy rates vary with age (χ 2 = 43.62, P < 0.001). Risk of having a suboptimal radiograph increases above the age of 60-years (χ 2 = 4.45, P < 0.05). The annual cost of repeat radiographs was £56,200 per hospital. Discussion and conclusion High rates of pelvic radiograph inadequacy can lead to missed pathology and the requirement for repeat imaging, which has significant patient safety and financial implications. Risk factors for inadequate radiographs include older patients and those having out-of-hours imaging.

Comparison of Epson scanner quality for radiochromic film evaluation

PubMed Central

Alnawaf, Hani; Yu, Peter K.N.

2012-01-01

Epson Desktop scanners have been quoted as devices which match the characteristics required for the evaluation of radiation dose exposure by radiochromic films. Specifically, models such as the 10000XL have been used successfully for image analysis and are recommended by ISP for dosimetry purposes. This note investigates and compares the scanner characteristics of three Epson desktop scanner models including the Epson 10000XL, V700, and V330. Both of the latter are substantially cheaper models capable of A4 scanning. As the price variation between the V330 and the 10000XL is 20‐fold (based on Australian recommended retail price), cost savings by using the cheaper scanners may be warranted based on results. By a direct comparison of scanner uniformity and reproducibility we can evaluate the accuracy of these scanners for radiochromic film dosimetry. Results have shown that all three scanners can produce adequate scanner uniformity and reproducibility, with the inexpensive V330 producing a standard deviation variation across its landscape direction of 0.7% and 1.2% in the portrait direction (reflection mode). This is compared to the V700 in reflection mode of 0.25% and 0.5% for landscape and portrait directions, respectively, and 0.5% and 0.8% for the 10000XL. In transmission mode, the V700 is comparable in reproducibility to the 10000XL for portrait and landscape mode, whilst the V330 is only capable of scanning in the landscape direction and produces a standard deviation in this direction of 1.0% compared to 0.6% (V700) and 0.25% (10000XL). Results have shown that the V700 and 10000XL are comparable scanners in quality and accuracy with the 10000XL obviously capable of imaging over an A3 area as opposed to an A4 area for the V700. The V330 scanner produced slightly lower accuracy and quality with uncertainties approximately twice as much as the other scanners. However, the results show that the V330 is still an adequate scanner and could be used for radiation dosimetry purposes. As such, if budgetary requirements are limited, the V700 scanner would be the recommended option at a price eight times cheaper than the 10000XL; however, the V330 produces adequate results at a price which is 2.5 times cheaper again. This may be a consideration for smaller institutions or individuals working with radiochromic film dosimetry. PACS number: 87.55.Qr; 87.56.Fc PMID:22955661

Comparison of Epson scanner quality for radiochromic film evaluation.

PubMed

Alnawaf, Hani; Yu, Peter K N; Butson, Martin

2012-09-06

Epson Desktop scanners have been quoted as devices which match the characteristics required for the evaluation of radiation dose exposure by radiochromic films. Specifically, models such as the 10000XL have been used successfully for image analysis and are recommended by ISP for dosimetry purposes. This note investigates and compares the scanner characteristics of three Epson desktop scanner models including the Epson 10000XL, V700, and V330. Both of the latter are substantially cheaper models capable of A4 scanning. As the price variation between the V330 and the 10000XL is 20-fold (based on Australian recommended retail price), cost savings by using the cheaper scanners may be warranted based on results. By a direct comparison of scanner uniformity and reproducibility we can evaluate the accuracy of these scanners for radiochromic film dosimetry. Results have shown that all three scanners can produce adequate scanner uniformity and reproducibility, with the inexpensive V330 producing a standard deviation variation across its landscape direction of 0.7% and 1.2% in the portrait direction (reflection mode). This is compared to the V700 in reflection mode of 0.25% and 0.5% for landscape and portrait directions, respectively, and 0.5% and 0.8% for the 10000XL. In transmission mode, the V700 is comparable in reproducibility to the 10000XL for portrait and landscape mode, whilst the V330 is only capable of scanning in the landscape direction and produces a standard deviation in this direction of 1.0% compared to 0.6% (V700) and 0.25% (10000XL). Results have shown that the V700 and 10000XL are comparable scanners in quality and accuracy with the 10000XL obviously capable of imaging over an A3 area as opposed to an A4 area for the V700. The V330 scanner produced slightly lower accuracy and quality with uncertainties approximately twice as much as the other scanners. However, the results show that the V330 is still an adequate scanner and could be used for radiation dosimetry purposes. As such, if budgetary requirements are limited, the V700 scanner would be the recommended option at a price eight times cheaper than the 10000XL; however, the V330 produces adequate results at a price which is 2.5 times cheaper again. This may be a consideration for smaller institutions or individuals working with radiochromic film dosimetry.

Automated calibration of the Suomi National Polar-Orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) reflective solar bands

NASA Astrophysics Data System (ADS)

Rausch, Kameron; Houchin, Scott; Cardema, Jason; Moy, Gabriel; Haas, Evan; De Luccia, Frank J.

2013-12-01

National Polar-Orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) reflective bands are currently calibrated via weekly updates to look-up tables (LUTs) utilized by operational ground processing in the Joint Polar Satellite System Interface Data Processing Segment (IDPS). The parameters in these LUTs must be predicted ahead 2 weeks and cannot adequately track the dynamically varying response characteristics of the instrument. As a result, spurious "predict-ahead" calibration errors of the order of 0.1% or greater are routinely introduced into the calibrated reflectances and radiances produced by IDPS in sensor data records (SDRs). Spurious calibration errors of this magnitude adversely impact the quality of downstream environmental data records (EDRs) derived from VIIRS SDRs such as Ocean Color/Chlorophyll and cause increased striping and band-to-band radiometric calibration uncertainty of SDR products. A novel algorithm that fully automates reflective band calibration has been developed for implementation in IDPS in late 2013. Automating the reflective solar band (RSB) calibration is extremely challenging and represents a significant advancement over the manner in which RSB calibration has traditionally been performed in heritage instruments such as the Moderate Resolution Imaging Spectroradiometer. The automated algorithm applies calibration data almost immediately after their acquisition by the instrument from views of space and on-onboard calibration sources, thereby eliminating the predict-ahead errors associated with the current offline calibration process. This new algorithm, when implemented, will significantly improve the quality of VIIRS reflective band SDRs and consequently the quality of EDRs produced from these SDRs.

3D models mapping optimization through an integrated parameterization approach: cases studies from Ravenna

NASA Astrophysics Data System (ADS)

Cipriani, L.; Fantini, F.; Bertacchi, S.

2014-06-01

Image-based modelling tools based on SfM algorithms gained great popularity since several software houses provided applications able to achieve 3D textured models easily and automatically. The aim of this paper is to point out the importance of controlling models parameterization process, considering that automatic solutions included in these modelling tools can produce poor results in terms of texture utilization. In order to achieve a better quality of textured models from image-based modelling applications, this research presents a series of practical strategies aimed at providing a better balance between geometric resolution of models from passive sensors and their corresponding (u,v) map reference systems. This aspect is essential for the achievement of a high-quality 3D representation, since "apparent colour" is a fundamental aspect in the field of Cultural Heritage documentation. Complex meshes without native parameterization have to be "flatten" or "unwrapped" in the (u,v) parameter space, with the main objective to be mapped with a single image. This result can be obtained by using two different strategies: the former automatic and faster, while the latter manual and time-consuming. Reverse modelling applications provide automatic solutions based on splitting the models by means of different algorithms, that produce a sort of "atlas" of the original model in the parameter space, in many instances not adequate and negatively affecting the overall quality of representation. Using in synergy different solutions, ranging from semantic aware modelling techniques to quad-dominant meshes achieved using retopology tools, it is possible to obtain a complete control of the parameterization process.

2.2 Å resolution cryo-EM structure of β-galactosidase in complex with a cell-permeant inhibitor.

PubMed

Bartesaghi, Alberto; Merk, Alan; Banerjee, Soojay; Matthies, Doreen; Wu, Xiongwu; Milne, Jacqueline L S; Subramaniam, Sriram

2015-06-05

Cryo-electron microscopy (cryo-EM) is rapidly emerging as a powerful tool for protein structure determination at high resolution. Here we report the structure of a complex between Escherichia coli β-galactosidase and the cell-permeant inhibitor phenylethyl β-D-thiogalactopyranoside (PETG), determined by cryo-EM at an average resolution of ~2.2 angstroms (Å). Besides the PETG ligand, we identified densities in the map for ~800 water molecules and for magnesium and sodium ions. Although it is likely that continued advances in detector technology may further enhance resolution, our findings demonstrate that preparation of specimens of adequate quality and intrinsic protein flexibility, rather than imaging or image-processing technologies, now represent the major bottlenecks to routinely achieving resolutions close to 2 Å using single-particle cryo-EM. Copyright © 2015, American Association for the Advancement of Science.

First-in-human experience using the Volcano VIBE-RX vascular imaging balloon catheter system (Volcano IVUS-guided Balloon Evaluation - New Zealand: VIBE-NZ Study).

PubMed

Watson, Timothy; El-Jack, Seifeddin; Stewart, James T; Ormiston, John

2013-09-01

Intravascular ultrasound (IVUS) is a proven and safe imaging modality used to guide percutaneous coronary intervention (PCI). The Volcano VIBE™ RX Vascular Imaging Balloon Catheter is a novel rapid exchange, 0.014" wire-compatible multi-lumen conventional balloon catheter modified with the addition of an IVUS transducer proximal to the balloon, delivered via a standard 6 Fr sheath. We sought to evaluate the safety, balloon performance, and image quality of the VIBE™ RX in patients scheduled for coronary intervention. Patients aged >21 and <85 years with single or multivessel coronary disease scheduled for PCI due to coronary ischaemic symptoms were included. Those with angiographic features that precluded the safe or informative use of the device were excluded. Twenty-nine patients having angiography because of ischaemic symptoms underwent 44 VIBE RX imaging runs, with balloon dilation in 20. Successful device deployment was achieved in all but one patient. All images were adequate and reproducible. One patient had a non-ST-elevation MI felt to be due to the complexity of the procedure rather than directly related to the VIBE™ RX. The study demonstrated the safety and effectiveness of the VIBE™ RX for its intended purpose with minimal failure rate and no directly related complications.

Anatomic study of the canine stifle using low-field magnetic resonance imaging (MRI) and MRI arthrography.

PubMed

Pujol, Esteban; Van Bree, Henri; Cauzinille, Laurent; Poncet, Cyrill; Gielen, Ingrid; Bouvy, Bernard

2011-06-01

To investigate the use of low-field magnetic resonance imaging (MRI) and MR arthrography in normal canine stifles and to compare MRI images to gross dissection. Descriptive study. Adult canine pelvic limbs (n=17). Stifle joints from 12 dogs were examined by orthopedic and radiographic examination, synovial fluid analysis, and MRI performed using a 0.2 T system. Limbs 1 to 7 were used to develop the MR and MR arthrography imaging protocol. Limbs 8-17 were studied with the developed MR and MR arthrography protocol and by gross dissection. Three sequences were obtained: T1-weighted spin echo (SE) in sagittal, dorsal, and transverse plane; T2-weighted SE in sagittal plane and T1-gradient echo in sagittal plane. Specific bony and soft tissue structures were easily identifiable with the exception of articular cartilage. The cranial and caudal cruciate ligaments were identified. Medial and lateral menisci were seen as wedge-shaped hypointense areas. MR arthrography permitted further delineation of specific structures. MR images corresponded with gross dissection morphology. With the exception of poor delineation of articular cartilage, a low-field MRI and MR arthrography protocol provides images of adequate quality to assess the normal canine stifle joint. © Copyright 2011 by The American College of Veterinary Surgeons.

In vivo imaging of superficial femoral artery (SFA) stents for deformation analysis

NASA Astrophysics Data System (ADS)

Ganguly, A.; Schneider, A.; Keck, B.; Bennett, N. R.; Fahrig, R.

2008-03-01

A high-resolution (198 μm) C-arm CT imaging system (Axiom Artis dTA, Siemens Medical Solutions, Forchheim, Germany) was optimized for imaging superficial femoral artery (SFA) stents in humans. The SFA is susceptible to the development of atherosclerotic lesions. These are typically treated with angioplasty and stent deployment. However, these stents can have a fracture rate as high as 35%. Fracture is usually accompanied by restenosis and reocclusion. The exact cause of breakage is unknown and is hypothesized to result from deforming forces due to hip and knee flexion. Imaging was performed with the leg placed in both straight and bent positions. Projection images obtained during 20 s scans with ~200° of rotation of the C-arm were back-projected to obtain 3D volumes. Using a semi-automatic software algorithm developed in-house, the stent centerlines were found and ellipses were fitted to the slice normals. Image quality was adequate for calculations in 11/13 subjects. Bending the leg was found to shorten the stents in 10/11 cases with the maximum change being 9% (12 mm in a 133 mm stent), and extend the stent in one case by 1.6%. The maximum eccentricity change was 36% with a bend angle of 72° in a case where the stent extended behind the knee.

How does C-VIEW image quality compare with conventional 2D FFDM?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, Jeffrey S., E-mail: nelson.jeffrey@duke.edu; Wells, Jered R.; Baker, Jay A.

Purpose: The FDA approved the use of digital breast tomosynthesis (DBT) in 2011 as an adjunct to 2D full field digital mammography (FFDM) with the constraint that all DBT acquisitions must be paired with a 2D image to assure adequate interpretative information is provided. Recently manufacturers have developed methods to provide a synthesized 2D image generated from the DBT data with the hope of sparing patients the radiation exposure from the FFDM acquisition. While this much needed alternative effectively reduces the total radiation burden, differences in image quality must also be considered. The goal of this study was to comparemore » the intrinsic image quality of synthesized 2D C-VIEW and 2D FFDM images in terms of resolution, contrast, and noise. Methods: Two phantoms were utilized in this study: the American College of Radiology mammography accreditation phantom (ACR phantom) and a novel 3D printed anthropomorphic breast phantom. Both phantoms were imaged using a Hologic Selenia Dimensions 3D system. Analysis of the ACR phantom includes both visual inspection and objective automated analysis using in-house software. Analysis of the 3D anthropomorphic phantom includes visual assessment of resolution and Fourier analysis of the noise. Results: Using ACR-defined scoring criteria for the ACR phantom, the FFDM images scored statistically higher than C-VIEW according to both the average observer and automated scores. In addition, between 50% and 70% of C-VIEW images failed to meet the nominal minimum ACR accreditation requirements—primarily due to fiber breaks. Software analysis demonstrated that C-VIEW provided enhanced visualization of medium and large microcalcification objects; however, the benefits diminished for smaller high contrast objects and all low contrast objects. Visual analysis of the anthropomorphic phantom showed a measureable loss of resolution in the C-VIEW image (11 lp/mm FFDM, 5 lp/mm C-VIEW) and loss in detection of small microcalcification objects. Spectral analysis of the anthropomorphic phantom showed higher total noise magnitude in the FFDM image compared with C-VIEW. Whereas the FFDM image contained approximately white noise texture, the C-VIEW image exhibited marked noise reduction at midfrequency and high frequency with far less noise suppression at low frequencies resulting in a mottled noise appearance. Conclusions: Their analysis demonstrates many instances where the C-VIEW image quality differs from FFDM. Compared to FFDM, C-VIEW offers a better depiction of objects of certain size and contrast, but provides poorer overall resolution and noise properties. Based on these findings, the utilization of C-VIEW images in the clinical setting requires careful consideration, especially if considering the discontinuation of FFDM imaging. Not explicitly explored in this study is how the combination of DBT + C-VIEW performs relative to DBT + FFDM or FFDM alone.« less

A real time study on condition monitoring of distribution transformer using thermal imager

NASA Astrophysics Data System (ADS)

Mariprasath, T.; Kirubakaran, V.

2018-05-01

The transformer is one of the critical apparatus in the power system. At any cost, a few minutes of outages harshly influence the power system. Hence, prevention-based maintenance technique is very essential. The continuous conditioning and monitoring technology significantly increases the life span of the transformer, as well as reduces the maintenance cost. Hence, conditioning and monitoring of transformer's temperature are very essential. In this paper, a critical review has been made on various conditioning and monitoring techniques. Furthermore, a new method, hot spot indication technique, is discussed. Also, transformer's operating condition is monitored by using thermal imager. From the thermal analysis, it is inferred that major hotspot locations are appearing at connection lead out; also, the bushing of the transformer is the very hottest spot in transformer, so monitoring the level of oil is essential. Alongside, real time power quality analysis has been carried out using the power analyzer. It shows that industrial drives are injecting current harmonics to the distribution network, which causes the power quality problem on the grid. Moreover, the current harmonic limit has exceeded the IEEE standard limit. Hence, the adequate harmonics suppression technique is need an hour.

PET and PVC separation with hyperspectral imagery.

PubMed

Moroni, Monica; Mei, Alessandro; Leonardi, Alessandra; Lupo, Emanuela; Marca, Floriana La

2015-01-20

Traditional plants for plastic separation in homogeneous products employ material physical properties (for instance density). Due to the small intervals of variability of different polymer properties, the output quality may not be adequate. Sensing technologies based on hyperspectral imaging have been introduced in order to classify materials and to increase the quality of recycled products, which have to comply with specific standards determined by industrial applications. This paper presents the results of the characterization of two different plastic polymers--polyethylene terephthalate (PET) and polyvinyl chloride (PVC)--in different phases of their life cycle (primary raw materials, urban and urban-assimilated waste and secondary raw materials) to show the contribution of hyperspectral sensors in the field of material recycling. This is accomplished via near-infrared (900-1700 nm) reflectance spectra extracted from hyperspectral images acquired with a two-linear-spectrometer apparatus. Results have shown that a rapid and reliable identification of PET and PVC can be achieved by using a simple two near-infrared wavelength operator coupled to an analysis of reflectance spectra. This resulted in 100% classification accuracy. A sensor based on this identification method appears suitable and inexpensive to build and provides the necessary speed and performance required by the recycling industry.

PET and PVC Separation with Hyperspectral Imagery

PubMed Central

Moroni, Monica; Mei, Alessandro; Leonardi, Alessandra; Lupo, Emanuela; La Marca, Floriana

2015-01-01

Traditional plants for plastic separation in homogeneous products employ material physical properties (for instance density). Due to the small intervals of variability of different polymer properties, the output quality may not be adequate. Sensing technologies based on hyperspectral imaging have been introduced in order to classify materials and to increase the quality of recycled products, which have to comply with specific standards determined by industrial applications. This paper presents the results of the characterization of two different plastic polymers—polyethylene terephthalate (PET) and polyvinyl chloride (PVC)—in different phases of their life cycle (primary raw materials, urban and urban-assimilated waste and secondary raw materials) to show the contribution of hyperspectral sensors in the field of material recycling. This is accomplished via near-infrared (900–1700 nm) reflectance spectra extracted from hyperspectral images acquired with a two-linear-spectrometer apparatus. Results have shown that a rapid and reliable identification of PET and PVC can be achieved by using a simple two near-infrared wavelength operator coupled to an analysis of reflectance spectra. This resulted in 100% classification accuracy. A sensor based on this identification method appears suitable and inexpensive to build and provides the necessary speed and performance required by the recycling industry. PMID:25609050

21 CFR 110.80 - Processes and controls.

Code of Federal Regulations, 2011 CFR

2011-04-01

... safe and of adequate sanitary quality. (12) Batters, breading, sauces, gravies, dressings, and other...) Cooling to an adequate temperature during manufacturing. (vi) Disposing of batters at appropriate...

Network design and quality checks in automatic orientation of close-range photogrammetric blocks.

PubMed

Dall'Asta, Elisa; Thoeni, Klaus; Santise, Marina; Forlani, Gianfranco; Giacomini, Anna; Roncella, Riccardo

2015-04-03

Due to the recent improvements of automatic measurement procedures in photogrammetry, multi-view 3D reconstruction technologies are becoming a favourite survey tool. Rapidly widening structure-from-motion (SfM) software packages offer significantly easier image processing workflows than traditional photogrammetry packages. However, while most orientation and surface reconstruction strategies will almost always succeed in any given task, estimating the quality of the result is, to some extent, still an open issue. An assessment of the precision and reliability of block orientation is necessary and should be included in every processing pipeline. Such a need was clearly felt from the results of close-range photogrammetric surveys of in situ full-scale and laboratory-scale experiments. In order to study the impact of the block control and the camera network design on the block orientation accuracy, a series of Monte Carlo simulations was performed. Two image block configurations were investigated: a single pseudo-normal strip and a circular highly-convergent block. The influence of surveying and data processing choices, such as the number and accuracy of the ground control points, autofocus and camera calibration was investigated. The research highlights the most significant aspects and processes to be taken into account for adequate in situ and laboratory surveys, when modern SfM software packages are used, and evaluates their effect on the quality of the results of the surface reconstruction.

Cranial surgery navigation aided by a compact intraoperative magnetic resonance imager.

PubMed

Schulder, M; Liang, D; Carmel, P W

2001-06-01

In this article the authors report on a novel, compact device for magnetic resonance (MR) imaging that has been developed for use in a standard neurosurgical operating room. The device includes a permanent magnet with a field strength of 0.12 tesla. The poles of the magnet are vertically aligned, with a gap of 25 cm. When not in use the magnet is stored in a shielded cage in a corner of the operating room; it is easily moved into position and attaches to a regular operating table. The magnet is raised for imaging when needed and may be lowered to allow surgery to proceed unencumbered. Surgical navigation with optical and/or magnetic probes is incorporated into the system. Twenty-five patients have undergone removal of intracranial lesions with the aid of this device. Operations included craniotomy for tumor or other lesion in 18 patients and transsphenoidal resection of tumor in seven. The number of scans ranged from two to five per surgery (average 3.4); image quality was excellent in 45%, adequate in 43%, and poor in 12%. In four patients MR imaging revealed additional tumor that was then resected; in five others visual examination of the operative field was inconclusive but complete tumor removal was confirmed on MR imaging. In 21 patients early postoperative diagnostic MR studies corroborated the findings on the final intraoperative MR image. Using a water-covered phantom, the accuracy of the navigational tools was assessed; 120 data points were measured. The accuracy of the magnetic probe averaged 1.3 mm and 2.1 mm in the coronal and axial planes, respectively; the optical probe accuracy was 2.1 mm and 1.8 mm in those planes. This device provides high-quality intraoperative imaging and accurate surgical navigation with minimal disruption in a standard neurosurgical operating room.

SNPP VIIRS Spectral Bands Co-Registration and Spatial Response Characterization

NASA Technical Reports Server (NTRS)

Lin, Guoqing; Tilton, James C.; Wolfe, Robert E.; Tewari, Krishna P.; Nishihama, Masahiro

2013-01-01

The Visible Infrared Imager Radiometer Suite (VIIRS) instrument onboard the Suomi National Polar-orbiting Partnership (SNPP) satellite was launched on 28 October 2011. The VIIRS has 5 imagery spectral bands (I-bands), 16 moderate resolution spectral bands (M-bands) and a panchromatic day/night band (DNB). Performance of the VIIRS spatial response and band-to-band co-registration (BBR) was measured through intensive pre-launch tests. These measurements were made in the non-aggregated zones near the start (or end) of scan for the I-bands and M-bands and for a limited number of aggregation modes for the DNB in order to test requirement compliance. This paper presents results based on a recently re-processed pre-launch test data. Sensor (detector) spatial impulse responses in the scan direction are parameterized in terms of ground dynamic field of view (GDFOV), horizontal spatial resolution (HSR), modulation transfer function (MTF), ensquared energy (EE) and integrated out-of-pixel (IOOP) spatial response. Results are presented for the non-aggregation, 2-sample and 3-sample aggregation zones for the I-bands and M-bands, and for a limited number of aggregation modes for the DNB. On-orbit GDFOVs measured for the 5 I-bands in the scan direction using a straight bridge are also presented. Band-to-band co-registration (BBR) is quantified using the prelaunch measured band-to-band offsets. These offsets may be expressed as fractions of horizontal sampling intervals (HSIs), detector spatial response parameters GDFOV or HSR. BBR bases on HSIs in the non-aggregation, 2-sample and 3-sample aggregation zones are presented. BBR matrices based on scan direction GDFOV and HSR are compared to the BBR matrix based on HSI in the non-aggregation zone. We demonstrate that BBR based on GDFOV is a better representation of footprint overlap and so this definition should be used in BBR requirement specifications. We propose that HSR not be used as the primary image quality indicator, since we show that it is neither an adequate representation of the size of sensor spatial response nor an adequate measure of imaging quality.

Diffuse reflectance imaging: a tool for guided biopsy

NASA Astrophysics Data System (ADS)

Jayanthi, Jayaraj L.; Subhash, Narayanan; Manju, Stephen; Nisha, Unni G.; Beena, Valappil T.

2012-01-01

Accurate diagnosis of premalignant or malignant oral lesions depends on the quality of the biopsy, adequate clinical information and correct interpretation of the biopsy results. The major clinical challenge is to precisely locate the biopsy site in a clinically suspicious lesion. Dips due to oxygenated hemoglobin absorption have been noticed at 545 and 575 nm in the diffusely reflected white light spectra of oral mucosa and the intensity ratio R545/R575 has been found suited for early detection of oral pre-cancers. A multi-spectral diffuse reflectance (DR) imaging system has been developed consisting of an electron multiplying charge coupled device (EMCCD) camera and a liquid crystal tunable filter for guiding the clinician to an optimal biopsy site. Towards this DR images were recorded from 27 patients with potentially malignant lesions on their tongue (dorsal, lateral and ventral sides) and from 44 healthy controls at 545 and 575 nm with the DR imaging system. False colored ratio image R545/R575 of the lesion provides a visual discerning capability that helps in locating the most malignant site for biopsy. Histopathological report of guided biopsy showed that out of the 27 patients 16 were cancers, 9 pre-cancers and 2 lichen planus. In this clinical trial DR imaging has correctly guided 25 biopsy sites, yielding a sensitivity of 93% and a specificity of 98%, thereby establishing the potential of DR imaging as a tool for guided biopsy.

Identification of Particles in Parenteral Drug Raw Materials.

PubMed

Lee, Kathryn; Lankers, Markus; Valet, Oliver

2018-04-18

Particles in drug products are not good and are therefore regulated. These particles can come from the very beginning of the manufacturing process, from the raw materials. To prevent particles, it is important to understand what they are and where they come from so the raw material quality, processing, and shipping can be improved. Thus, it is important to correctly identify particles seen in raw materials. Raw materials need to be of a certain quality with respect to physical and chemical composition, and need to have no contaminants in the form of particles which could contaminate the product or indicate the raw materials are not pure enough to make a good quality product. Particles are often seen when handling raw materials due to color, size, or shape characteristics different from those in the raw materials. Particles may appear to the eye to be very different things than they actually are, so microscope, chemical, and elemental analyses are required for accuracy in proper identification. This paper shows how using three different spectroscopy tools correctly and together can be used to identify particles from extrinsic, intrinsic, and inherent particles. Sources of materials can be humans and the environment (extrinsic), from within the process (intrinsic), and part of the formulation (inherent). Microscope versions of Raman spectroscopy, laser-induced breakdown spectroscopy (LIBS), and IR spectroscopy are excellent tools for identifying particles because they are fast and accurate techniques needing minimal sample preparation that can provide chemical composition as well as images that can be used for identification. The micro analysis capabilities allow for easy analysis of different portions of samples so multiple components can be identified and sample preparation can be reduced. Using just one of these techniques may not be sufficient to give adequate identification results so that the source of contamination can be adequately identified. The complementarity of the techniques provides the advantage of identifying various chemical and molecular components, as well as elemental and image analyses. Correct interpretation of the results from these techniques is also very important. Copyright © 2018, Parenteral Drug Association.

Methodological approach for the assessment of ultrasound reproducibility of cardiac structure and function: a proposal of the study group of Echocardiography of the Italian Society of Cardiology (Ultra Cardia SIC) Part I

PubMed Central

2011-01-01

When applying echo-Doppler imaging for either clinical or research purposes it is very important to select the most adequate modality/technology and choose the most reliable and reproducible measurements. Quality control is a mainstay to reduce variability among institutions and operators and must be obtained by using appropriate procedures for data acquisition, storage and interpretation of echo-Doppler data. This goal can be achieved by employing an echo core laboratory (ECL), with the responsibility for standardizing image acquisition processes (performed at the peripheral echo-labs) and analysis (by monitoring and optimizing the internal intra- and inter-reader variability of measurements). Accordingly, the Working Group of Echocardiography of the Italian Society of Cardiology decided to design standardized procedures for imaging acquisition in peripheral laboratories and reading procedures and to propose a methodological approach to assess the reproducibility of echo-Doppler parameters of cardiac structure and function by using both standard and advanced technologies. A number of cardiologists experienced in cardiac ultrasound was involved to set up an ECL available for future studies involving complex imaging or including echo-Doppler measures as primary or secondary efficacy or safety end-points. The present manuscript describes the methodology of the procedures (imaging acquisition and measurement reading) and provides the documentation of the work done so far to test the reproducibility of the different echo-Doppler modalities (standard and advanced). These procedures can be suggested for utilization also in non referall echocardiographic laboratories as an "inside" quality check, with the aim at optimizing clinical consistency of echo-Doppler data. PMID:21943283

How to evaluate the microcirculation: report of a round table conference

PubMed Central

De Backer, Daniel; Hollenberg, Steven; Boerma, Christiaan; Goedhart, Peter; Büchele, Gustavo; Ospina-Tascon, Gustavo; Dobbe, Iwan; Ince, Can

2007-01-01

Introduction Microvascular alterations may play an important role in the development of organ failure in critically ill patients and especially in sepsis. Recent advances in technology have allowed visualization of the microcirculation, but several scoring systems have been used so it is sometimes difficult to compare studies. This paper reports the results of a round table conference that was organized in Amsterdam in November 2006 in order to achieve consensus on image acquisition and analysis. Methods The participants convened to discuss the various aspects of image acquisition and the different scores, and a consensus statement was drafted using the Delphi methodology. Results The participants identified the following five key points for optimal image acquisition: five sites per organ, avoidance of pressure artifacts, elimination of secretions, adequate focus and contrast adjustment, and recording quality. The scores that can be used to describe numerically the microcirculatory images consist of the following: a measure of vessel density (total and perfused vessel density; two indices of perfusion of the vessels (proportion of perfused vessels and microcirculatory flow index); and a heterogeneity index. In addition, this information should be provided for all vessels and for small vessels (mostly capillaries) identified as smaller than 20 μm. Venular perfusion should be reported as a quality control index, because venules should always be perfused in the absence of pressure artifact. It is anticipated that although this information is currently obtained manually, it is likely that image analysis software will ease analysis in the future. Conclusion We proposed that scoring of the microcirculation should include an index of vascular density, assessment of capillary perfusion and a heterogeneity index. PMID:17845716

76 FR 43167 - Approval and Promulgation of Air Quality Implementation Plan; North Carolina; Disapproval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-20

... stated that the state's conclusion should be supported by an adequate technical analysis. Second, EPA... revision must be supported by an adequate technical analysis, including, but not limited to, information... disapproval where the Agency states: ``* * * without an adequate technical analysis EPA does not believe that...

76 FR 43159 - Approval and Promulgation of Air Quality Implementation Plan; Georgia; Disapproval of Interstate...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-20

... stated that the state's conclusion should be supported by an adequate technical analysis. Second, EPA...'' provisions, the state's SIP revision must be supported by an adequate technical analysis, including, but not..., proposed disapproval where the Agency states: ``* * * without an adequate technical analysis EPA does not...

76 FR 43128 - Approval and Promulgation of Air Quality Implementation Plan; Alabama; Disapproval of Interstate...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-20

..., if so, address the impact. The state's conclusion must be supported by an adequate technical analysis...'' provisions, the state's SIP revision must be supported by an adequate technical analysis, including, but not... disapproval where the Agency states: ``* * *without an adequate technical analysis EPA does not believe that...

Severe oligohydramnios with intact membranes: an indication for diagnostic amnioinfusion.

PubMed

Pryde, P G; Hallak, M; Lauria, M R; Littman, L; Bottoms, S F; Johnson, M P; Evans, M I

2000-01-01

To quantify the improvement in ultrasonographic fetal imaging following diagnostic amnioinfusion for the indication of unexplained midtrimester oligohydramnios. Patients referred for unexplained midtrimester oligohydramnios were retrospectively reviewed. Videotapes of those undergoing diagnostic antenatal amnioinfusion were analyzed for quality of visualization of routinely imaged structures before and after the infusion procedure. The overall rate of adequate visualization of fetal structures improved from 50.98 to 76.79% (p < 0.0001). In fetuses having preinfusion-identified obstructive uropathy, there was improvement in identification of associated anomalies from 11.8 to 31.3%. Several authors have suggested that diagnostic amnioinfusion can facilitate fetal imaging and increase diagnostic precision in the setting of unexplained severe oligohydramnios. We have quantified the improvement in the rate of optimal visualization of fetal structures which likely translates, in experienced hands, into this observed improved diagnostic precision. Of particular importance is the improvement in appreciation of associated anomalies in cases of obstructive uropathy in which such findings may determine whether or not invasive fetal therapy is indicated. Copyright 2000 S. Karger AG, Basel.

Slice-thickness evaluation in CT and MRI: an alternative computerised procedure.

PubMed

Acri, G; Tripepi, M G; Causa, F; Testagrossa, B; Novario, R; Vermiglio, G

2012-04-01

The efficient use of computed tomography (CT) and magnetic resonance imaging (MRI) equipment necessitates establishing adequate quality-control (QC) procedures. In particular, the accuracy of slice thickness (ST) requires scan exploration of phantoms containing test objects (plane, cone or spiral). To simplify such procedures, a novel phantom and a computerised LabView-based procedure have been devised, enabling determination of full width at half maximum (FWHM) in real time. The phantom consists of a polymethyl methacrylate (PMMA) box, diagonally crossed by a PMMA septum dividing the box into two sections. The phantom images were acquired and processed using the LabView-based procedure. The LabView (LV) results were compared with those obtained by processing the same phantom images with commercial software, and the Fisher exact test (F test) was conducted on the resulting data sets to validate the proposed methodology. In all cases, there was no statistically significant variation between the two different procedures and the LV procedure, which can therefore be proposed as a valuable alternative to other commonly used procedures and be reliably used on any CT and MRI scanner.

[Restoration filtering based on projection power spectrum for single-photon emission computed tomography].

PubMed

Kubo, N

1995-04-01

To improve the quality of single-photon emission computed tomographic (SPECT) images, a restoration filter has been developed. This filter was designed according to practical "least squares filter" theory. It is necessary to know the object power spectrum and the noise power spectrum. The power spectrum is estimated from the power spectrum of a projection, when the high-frequency power spectrum of a projection is adequately approximated as a polynomial exponential expression. A study of the restoration with the filter based on a projection power spectrum was conducted, and compared with that of the "Butterworth" filtering method (cut-off frequency of 0.15 cycles/pixel), and "Wiener" filtering (signal-to-noise power spectrum ratio was a constant). Normalized mean-squared errors (NMSE) of the phantom, two line sources located in a 99mTc filled cylinder, were used. NMSE of the "Butterworth" filter, "Wiener" filter, and filtering based on a power spectrum were 0.77, 0.83, and 0.76 respectively. Clinically, brain SPECT images utilizing this new restoration filter improved the contrast. Thus, this filter may be useful in diagnosis of SPECT images.

Preoperative magnetic resonance imaging protocol for endoscopic cranial base image-guided surgery.

PubMed

Grindle, Christopher R; Curry, Joseph M; Kang, Melissa D; Evans, James J; Rosen, Marc R

2011-01-01

Despite the increasing utilization of image-guided surgery, no radiology protocols for obtaining magnetic resonance (MR) imaging of adequate quality are available in the current literature. At our institution, more than 300 endonasal cranial base procedures including pituitary, extended pituitary, and other anterior skullbase procedures have been performed in the past 3 years. To facilitate and optimize preoperative evaluation and assessment, there was a need to develop a magnetic resonance protocol. Retrospective Technical Assessment was performed. Through a collaborative effort between the otolaryngology, neurosurgery, and neuroradiology departments at our institution, a skull base MR image-guided (IGS) protocol was developed with several ends in mind. First, it was necessary to generate diagnostic images useful for the more frequently seen pathologies to improve work flow and limit the expense and inefficiency of case specific MR studies. Second, it was necessary to generate sequences useful for IGS, preferably using sequences that best highlight that lesion. Currently, at our institution, all MR images used for IGS are obtained using this protocol as part of preoperative planning. The protocol that has been developed allows for thin cut precontrast and postcontrast axial cuts that can be used to plan intraoperative image guidance. It also obtains a thin cut T2 axial series that can be compiled separately for intraoperative imaging, or may be fused with computed tomographic images for combined modality. The outlined protocol obtains image sequences effective for diagnostic and operative purposes for image-guided surgery using both T1 and T2 sequences. Copyright © 2011 Elsevier Inc. All rights reserved.

Wide-field-of-view millimeter-wave telescope design with ultra-low cross-polarization

NASA Astrophysics Data System (ADS)

Bernacki, Bruce E.; Kelly, James F.; Sheen, David; Hatchell, Brian; Valdez, Patrick; Tedeschi, Jonathan; Hall, Thomas; McMakin, Douglas

2012-06-01

As millimeter-wave arrays become available, off-axis imaging performance of the fore optics increases in importance due to the relatively large physical extent of the arrays. Typically, simple optical telescope designs are adapted to millimeter-wave imaging but single-mirror spherical or classic conic designs cannot deliver adequate image quality except near the optical axis. Since millimeter-wave designs are quasi-optical, optical ray tracing and commercial design software can be used to optimize designs to improve off-axis imaging as well as minimize cross-polarization. Methods that obey the Dragone-Mizuguchi condition for the design of reflective millimeter-wave telescopes with low cross-polarization also provide additional degrees of freedom that offer larger fields of view than possible with single-reflector designs. Dragone's graphical design method does not lend itself readily to computer-based optical design approaches, but subsequent authors expanded on Dragone's geometric design approach with analytic expressions that describe the location, shape, off-axis height and tilt of the telescope elements that satisfy Dragone's design rules and can be used as a first-order design for subsequent computer-based design and optimization. We investigate two design variants that obey the Dragone-Mizuguchi conditions that exhibit ultra-low cross-polarization and a large diffraction-limited field of view well suited to millimeter-wave imaging arrays.

Reference Values for Central Airway Dimensions on CT Images of Children and Adolescents.

PubMed

Kuo, Wieying; Ciet, Pierluigi; Andrinopoulou, Eleni-Rosalina; Chen, Yong; Pullens, Bas; Garcia-Peña, Pilar; Fleck, Robert J; Paoletti, Matteo; McCartin, Michael; Vermeulen, Francois; Morana, Giovanni; Lee, Edward Y; Tiddens, Harm A W M

2018-02-01

The purpose of this study was to acquire normative data on central airway dimensions on chest CT scans in the pediatric population. Chest CT findings reported as normal by a radiologist were collected retrospectively at 10 international centers. An experienced and independent thoracic radiologist reevaluated all CT scans for image quality and for normal findings. Semiautomated image analysis was performed to measure dimensions of the trachea and right and left main bronchi at inspiration. Intrathoracic tracheal length was measured from carina to thorax inlet. Cross-sectional area and short and long axes were measured perpendicular to the longitudinal airway axis starting from the carina every centimeter upward for the trachea and every 0.5 cm downward for the main bronchi. The effects on airway diameters of age, sex, intrathoracic tracheal length, and distance from the carina were investigated by use of mixed-effects models analysis. Among 1160 CT scans collected, 388 were evaluated as normal by the independent radiologist with sufficient image quality and adequate inspiratory volume level. Central airways were successfully semiautomatically analyzed in 294 of 388 CT studies. Age, sex, intrathoracic tracheal length, and distance from carina were all significant predictors in the models for tracheal and right and left main bronchial diameters (p < 0.001). The central airway dimensions increased with age up to 20 years, and dimensions were larger in male than in female adolescents. Normative data were determined for the central airways of children and adolescents. Central airway dimensions depended on distance from the carina and on intrathoracic tracheal length.

Predictive factors of health-related quality of life in patients with polycystic ovary syndrome: a structural equation modeling approach.

PubMed

Bazarganipour, Fatemeh; Ziaei, Saeide; Montazeri, Ali; Foroozanfard, Fatemeh; Kazemnejad, Anoshirvan; Faghihzadeh, Soghrat

2013-11-01

To determine association between health-related quality of life (HRQOL) and psychosexual variables in patients with polycystic ovary syndrome (PCOS). Cross-sectional study. Two private gynecology clinics. A sample of 300 women with PCOS were entered into the study and were subdivided into three groups: hyperandrogenism (HA) and PCO morphology; menstrual dysfunction and PCO morphology; menstrual dysfunction and HA and/or PCO morphology. Then each patient completed the following questionnaires: the Hospital Anxiety and Depression Scale, the Body Image Concern Inventory, the Rosenberg Self-Esteem Scale, the Short-Form Health Survey, and the Female Sexual Function Index. None. Both direct and indirect relationships among clinical symptoms, psychologic status, self-esteem, body image, and sexual function as independent predictors of HRQOL were examined with the use of structural equation modeling analysis. The clinical variables and psychologic distress had the strongest indirect relationships with HRQOL in the HA phenotype. The highest effect of PCOS symptoms on HRQOL impairment in patients with menstrual irregularities along with HA and patients with menstrual irregularities along with polycystic ovaries was exerted by clinical variables, poor perception of self-worth, negative body image, and sexual dysfunction. In patients with various phenotypes of PCOS, the effects of mediating variables on HRQOL are different. In patients with PCOS, the findings suggest that mediating factors, especially psychologic distress, self-esteem, body image, and sexual function, play an important role and should be taken into consideration and adequately treated if present. Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Ching-Ching, E-mail: cyang@tccn.edu.tw; Liu, Shu-Hsin; Mok, Greta S. P.

Purpose: This study aimed to tailor the CT imaging protocols for pediatric patients undergoing whole-body PET/CT examinations with appropriate attention to radiation exposure while maintaining adequate image quality for anatomic delineation of PET findings and attenuation correction of PET emission data. Methods: The measurements were made by using three anthropomorphic phantoms representative of 1-, 5-, and 10-year-old children with tube voltages of 80, 100, and 120 kVp, tube currents of 10, 40, 80, and 120 mA, and exposure time of 0.5 s at 1.75:1 pitch. Radiation dose estimates were derived from the dose-length product and were used to calculate riskmore » estimates for radiation-induced cancer. The influence of image noise on image contrast and attenuation map for CT scans were evaluated based on Pearson's correlation coefficient and covariance, respectively. Multiple linear regression methods were used to investigate the effects of patient age, tube voltage, and tube current on radiation-induced cancer risk and image noise for CT scans. Results: The effective dose obtained using three anthropomorphic phantoms and 12 combinations of kVp and mA ranged from 0.09 to 4.08 mSv. Based on our results, CT scans acquired with 80 kVp/60 mA, 80 kVp/80 mA, and 100 kVp/60 mA could be performed on 1-, 5-, and 10-year-old children, respectively, to minimize cancer risk due to CT scans while maintaining the accuracy of attenuation map and CT image contrast. The effective doses of the proposed protocols for 1-, 5- and 10-year-old children were 0.65, 0.86, and 1.065 mSv, respectively. Conclusions: Low-dose pediatric CT protocols were proposed to balance the tradeoff between radiation-induced cancer risk and image quality for patients ranging in age from 1 to 10 years old undergoing whole-body PET/CT examinations.« less

Chromotomosynthesis for high speed hyperspectral imagery

NASA Astrophysics Data System (ADS)

Bostick, Randall L.; Perram, Glen P.

2012-09-01

A rotating direct vision prism, chromotomosynthetic imaging (CTI) system operating in the visible creates hyperspectral imagery by collecting a set of 2D images with each spectrally projected at a different rotation angle of the prism. Mathematical reconstruction techniques that have been well tested in the field of medical physics are used to reconstruct the data to produce the 3D hyperspectral image. The instrument operates with a 100 mm focusing lens in the spectral range of 400-900 nm with a field of view of 71.6 mrad and angular resolution of 0.8-1.6 μrad. The spectral resolution is 0.6 nm at the shortest wavelengths, degrading to over 10 nm at the longest wavelengths. Measurements using a pointlike target show that performance is limited by chromatic aberration. The accuracy and utility of the instrument is assessed by comparing the CTI results to spatial data collected by a wideband image and hyperspectral data collected using a liquid crystal tunable filter (LCTF). The wide-band spatial content of the scene reconstructed from the CTI data is of same or better quality as a single frame collected by the undispersed imaging system with projections taken at every 1°. Performance is dependent on the number of projections used, with projections at 5° producing adequate results in terms of target characterization. The data collected by the CTI system can provide spatial information of equal quality as a comparable imaging system, provide high-frame rate slitless 1-D spectra, and generate 3-D hyperspectral imagery which can be exploited to provide the same results as a traditional multi-band spectral imaging system. While this prototype does not operate at high speeds, components exist which will allow for CTI systems to generate hyperspectral video imagery at rates greater than 100 Hz. The instrument has considerable potential for characterizing bomb detonations, muzzle flashes, and other battlefield combustion events.

Psychophysical evaluation of the image quality of a dynamic flat-panel digital x-ray image detector using the threshold contrast detail detectability (TCDD) technique

NASA Astrophysics Data System (ADS)

Davies, Andrew G.; Cowen, Arnold R.; Bruijns, Tom J. C.

1999-05-01

We are currently in an era of active development of the digital X-ray imaging detectors that will serve the radiological communities in the new millennium. The rigorous comparative physical evaluations of such devices are therefore becoming increasingly important from both the technical and clinical perspectives. The authors have been actively involved in the evaluation of a clinical demonstration version of a flat-panel dynamic digital X-ray image detector (or FDXD). Results of objective physical evaluation of this device have been presented elsewhere at this conference. The imaging performance of FDXD under radiographic exposure conditions have been previously reported, and in this paper a psychophysical evaluation of the FDXD detector operating under continuous fluoroscopic conditions is presented. The evaluation technique employed was the threshold contrast detail detectability (TCDD) technique, which enables image quality to be measured on devices operating in the clinical environment. This approach addresses image quality in the context of both the image acquisition and display processes, and uses human observers to measure performance. The Leeds test objects TO[10] and TO[10+] were used to obtain comparative measurements of performance on the FDXD and two digital spot fluorography (DSF) systems, one utilizing a Plumbicon camera and the other a state of the art CCD camera. Measurements were taken at a range of detector entrance exposure rates, namely 6, 12, 25 and 50 (mu) R/s. In order to facilitate comparisons between the systems, all fluoroscopic image processing such as noise reduction algorithms, were disabled during the experiments. At the highest dose rate FDXD significantly outperformed the DSF comparison systems in the TCDD comparisons. At 25 and 12 (mu) R/s all three-systems performed in an equivalent manner and at the lowest exposure rate FDXD was inferior to the two DSF systems. At standard fluoroscopic exposures, FDXD performed in an equivalent manner to the DSF systems for the TCDD comparisons. This would suggest that FDXD would therefore perform adequately in a clinical fluoroscopic environment and our initial clinical experiences support this. Noise reduction processing of the fluoroscopic data acquired on FDXD was also found to further improve TCDD performance for FDXD. FDXD therefore combines acceptable fluoroscopic performance with excellent radiographic (snap shot) imaging fidelity, allowing the possibility of a universal x-ray detector to be developed, based on FDXD's technology. It is also envisaged that fluoroscopic performance will be improved by the development of digital image enhancement techniques specifically tailored to the characteristics of the FDXD detector.

Region 8: Utah Adequate Letter (6/10/2005)

EPA Pesticide Factsheets

This letter from EPA to Utah Department of Environmental Quality determined Salt Lake Citys' and Ogdens' Carbon Monoxide (CO) maintenance plan for Motor Vehicle Emissions Budgets adequate for transportation conformity purposes.

Development of Whole Slide Imaging on Smartphones and Evaluation With ThinPrep Cytology Test Samples: Follow-Up Study

PubMed Central

Ma, Shuoxin; Yu, Hong; Jin, Yu-Biao; Zheng, Jun

2018-01-01

Background The smartphone-based whole slide imaging (WSI) system represents a low-cost and effective alternative to automatic scanners for telepathology. In a previous study, the development of one such solution, named scalable whole slide imaging (sWSI), was presented and analyzed. A clinical evaluation of its iOS version with 100 frozen section samples verified the diagnosis-readiness of the produced virtual slides. Objective The first aim of this study was to delve into the quantifying issues encountered in the development of an Android version. It should also provide insights into future high-resolution real-time feedback medical imaging apps on Android and invoke the awareness of smartphone manufacturers for collaboration. The second aim of this study was to further verify the clinical value of sWSI with cytology samples. This type is different from the frozen section samples in that they require finer detail on the cellular level. Methods During sWSI development on Android, it was discovered that many models do not support uncompressed camera pixel data with sufficient resolution and full field of view. The proportion of models supporting the optimal format was estimated in a test on 200 mainstream Android models. Other factors, including slower processing speed and camera preview freezing, also led to inferior performance of sWSI on Android compared with the iOS version. The processing speed was mostly determined by the central processing unit frequency in theory, and the relationship was investigated in the 200-model simulation experiment with physical devices. The camera preview freezing was caused by the lag between triggering photo capture and resuming preview. In the clinical evaluation, 100 ThinPrep cytology test samples covering 6 diseases were scanned with sWSI and compared against the ground truth of optical microscopy. Results Among the tested Android models, only 3.0% (6/200) provided an optimal data format, meeting all criteria of quality and efficiency. The image-processing speed demonstrated a positive relationship with the central processing unit frequency but to a smaller degree than expected and was highly model-dependent. The virtual slides produced by sWSI on Android and iOS of ThinPrep cytology test samples achieved similar high quality. Using optical microscopy as the ground truth, pathologists made a correct diagnosis on 87.5% (175/200) of the cases with sWSI virtual slides. Depending on the sWSI version and the pathologist in charge, the kappa value varied between .70 and .82. All participating pathologists considered the quality of the sWSI virtual slides in the experiment to be adequate for routine usage. Conclusions Limited by hardware and operating system support, the performance of sWSI on mainstream Android smartphones did not fully match the iOS version. However, in practice, this difference was not significant, and both were adequate for digitizing most of the sample types for telepathology consultation. PMID:29618454

iPads in Breast Imaging – A Phantom Study

PubMed Central

Hammon, M.; Schlechtweg, P. M.; Schulz-Wendtland, R.; Uder, M.; Schwab, S. A.

2014-01-01

Introduction: Modern tablet PCs as the iPad are becoming more and more integrated into medicine. The aim of this study was to evaluate the display quality of iPads regarding digital mammography. Materials and Methods: Three experienced readers compared the display quality of the iPad 2 and 3 with a dedicated 10 megapixel (MP) mammography liquid crystal display (LCD) screen in consensus using the standardized Contrast Detail Mammography (CDMAM) phantom. Phantom fields without agreement between the readers were classified as “uncertain”, correct 2 : 1 decisions were classified as “uncertain/readable”. In a second step display quality of the three reading devices was judged subjectively in a side by side comparison. Results: The 10 MP screen was superior to both iPads in 4 (phantom-)fields and inferior in 2 fields. Comparing the iPads, version 3 was superior in 4 fields and version 2 was superior in 1 field. However these differences were not significant. Total number of “uncertain” fields did not show significant differences. The number of “uncertain” fields was 15 with the 10 MP screen, 16 with the iPad 2 and 17 with the iPad 3 (p > 0.05), the number of “uncertain/readable” fields was 4, 7 and 8, respectively. Subjective image quality of the iPad 3 and the 10 MP screen was rated superior to the iPad 2. Conclusion: The evaluated iPads, especially in version 3, seem to be adequate to display mammograms in a diagnostic quality and thus could be useful e.g. for patient consultation, clinical demonstration or educational and teaching purposes. However primary mammogram reading should still be performed on dedicated large sized reading screens. PMID:24741126

The Beginning and Development of the Theranostic Approach in Nuclear Medicine, as Exemplified by the Radionuclide Pair 86Y and 90Y

PubMed Central

Rösch, Frank; Herzog, Hans; Qaim, Syed M.

2017-01-01

In the context of radiopharmacy and molecular imaging, the concept of theranostics entails a therapy-accompanying diagnosis with the aim of a patient-specific treatment. Using the adequate diagnostic radiopharmaceutical, the disease and the state of the disease are verified for an individual patient. The other way around, it verifies that the radiopharmaceutical in hand represents a target-specific and selective molecule: the “best one” for that individual patient. Transforming diagnostic imaging into quantitative dosimetric information, the optimum radioactivity (expressed in maximum radiation dose to the target tissue and tolerable dose to healthy organs) of the adequate radiotherapeutical is applied to that individual patient. This theranostic approach in nuclear medicine is traced back to the first use of the radionuclide pair 86Y/90Y, which allowed a combination of PET and internal radiotherapy. Whereas the β-emitting therapeutic radionuclide 90Y (t½ = 2.7 d) had been available for a long time via the 90Sr/90Y generator system, the β+ emitter 86Y (t½ = 14.7 h) had to be developed for medical application. A brief outline of the various aspects of radiochemical and nuclear development work (nuclear data, cyclotron irradiation, chemical processing, quality control, etc.) is given. In parallel, the paper discusses the methodology introduced to quantify molecular imaging of 86Y-labelled compounds in terms of multiple and long-term PET recordings. It highlights the ultimate goal of radiotheranostics, namely to extract the radiation dose of the analogue 90Y-labelled compound in terms of mGy or mSv per MBq 90Y injected. Finally, the current and possible future development of theranostic approaches based on different PET and therapy nuclides is discussed. PMID:28632200

Application of Scion image software to the simultaneous determination of curcuminoids in turmeric (Curcuma longa).

PubMed

Sotanaphun, Uthai; Phattanawasin, Panadda; Sriphong, Lawan

2009-01-01

Curcumin, desmethoxycurcumin and bisdesmethoxycurcumin are bioactive constituents of turmeric (Curcuma longa). Owing to their different potency, quality control of turmeric based on the content of each curcuminoid is more reliable than that based on total curcuminoids. However, to perform such an assay, high-cost instrument is needed. To develop a simple and low-cost method for the simultaneous quantification of three curcuminoids in turmeric using TLC and the public-domain software Scion Image. The image of a TLC chromatogram of turmeric extract was recorded using a digital scanner. The density of the TLC spot of each curcuminoid was analysed by the Scion Image software. The density value was transformed to concentration by comparison with the calibration curve of standard curcuminoids developed on the same TLC plate. The polynomial regression data for all curcuminoids showed good linear relationship with R(2) > 0.99 in the concentration range of 0.375-6 microg/spot. The limits of detection and quantitation were 43-73 and 143-242 ng/spot, respectively. The method gave adequate precision, accuracy and recovery. The contents of each curcuminoid determined using this method were not significantly different from those determined using the TLC densitometric method. TLC image analysis using Scion Image is shown to be a reliable method for the simultaneous analysis of the content of each curcuminoid in turmeric.

A quality analysis of clinical anaesthesia study protocols from the Chinese clinical trials registry according to the SPIRIT statement.

PubMed

Yang, Lei; Chen, Shouming; Yang, Di; Li, Jiajin; Wu, Taixiang; Zuo, Yunxia

2018-05-15

To learn about the overall quality of clinical anaesthesia study protocols from the Chinese Clinical Trials Registry and to discuss the way to improve study protocol quality. We defined completeness of each sub-item in SPIRIT as N/A (not applicable) or with a score of 0, 1, or 2. For each protocol, we calculated the proportion of adequately reported items (score = 2 and N/A) and unreported items (score = 0). Protocol quality was determined according to the proportion of reported items, with values >50% indicating high quality. Protocol quality was determined according to the proportion of reported items. For each sub-item in SPIRIT, we calculated the adequately reported rate (percentage of all protocols with score 2 and NA on one sub-item) as well as the unreported rate (percentage of all protocols with score 0 on one sub-item). Total 126 study protocols were available for assessment. Among these, 88.1% were assessed as being of low quality. By comparison, the percentage of low-quality protocols was 88.9% after the publication of the SPIRIT statement. Among the 51 SPIRIT sub-items, 18 sub-items had an unreported rate above 90% while 16 had a higher adequately reported rate than an unreported rate. The overall quality of clinical anaesthesia study protocols registered in the ChiCTR was poor. A mandatory protocol upload and self-check based on the SPIRIT statement during the trial registration process may improve protocol quality in the future.

Is carbon dioxide a safe and good alternative for diatrizoate meglumine as a contrast in digital subtraction angiography?

PubMed

Hegde, U N; Khanapet, M S; Rajapurkar, M M; Gang, S D; Gohel, K D; Rane, G; Parikh, P; Patil, D; Desai, T; Patil, P; Kelawala, N

2009-01-01

Contrast-induced nephropathy is well-known sequelae of iodinated contrast (diatrizoate meglumine). Carbon dioxide (CO(2)) can be used as an alternative contrast agent. The aim of this study was to compare the renal injury and the quality of images of aortogram using iodinated contrast versus CO(2) using digital subtraction angiography (DSA). This prospective randomized study was done in 29 healthy dogs using DSA aortogram. Dogs were randomly assigned to receive iodinated contrast or CO(2). 6-F pigtail catheter was introduced via femoral artery approach to perform aortogram under general anesthesia. Serum creatinine (S.Cr.) and urinary enzymes, namely: N-acetyl D-glucosaminidase (NAG), alanine aminopeptidase (AAP), and gamma glutamyl transferase (GGT), were measured before and 48 hours after aortogram. There was no change in S.Cr. in both the groups. Significantly more enzymuria was seen following iodinated contrast than CO(2). Enzymuria pre and postaortogram following the iodinated contrast was GGT: 14.9 +/- 5.92 vs. 26.2 +/- 15.1 (P = 0.001), NAG: 1.63 +/- 0.90 vs. 3.6 +/- 2.14 (P = 0.0001), and AAP: 1.51 +/- 0.75 vs. 3.38 2.41 (P = 0.001), and in the CO(2) group was GGT: 15.5 +/- 4.9 vs. 21.1 +/- 9.04 (P = 0.02), NAG: 2.12 +/- 1.06 vs. 3.82 3.27 (P = 0.08), and AAP: 1.28 +/- 0.76 vs. 2.51 +/- 1.72 (P = 0.03). More than 50% increase over the preprocedural value was significantly less following CO(2). Images obtained with iodinated contrast were superior to those with CO(2,) however, the quality of image with CO(2) was adequate for delineation of the renal artery and major branches. Both iodinated contrast and CO(2) cause significant enzymuria. More severe enzymuria (>50% increase) was seen significantly less with the use of CO(2). Quality of images is better with iodinated contrast.

Health-related quality of life in patients with polycystic ovary syndrome (PCOS): a model-based study of predictive factors.

PubMed

Bazarganipour, Fatemeh; Ziaei, Saeide; Montazeri, Ali; Foroozanfard, Fatemeh; Kazemnejad, Anoshirvan; Faghihzadeh, Soghrat

2014-04-01

Understanding the factors that contribute to health-related quality of life (HRQOL) is critical for developing the most appropriate interventions for improving or maintaining the HRQOL in polycystic ovary syndrome (PCOS) patients. This study sought to determine the most significant predictors of the HRQOL in patients with PCOS. This was a cross-sectional study of 300 women with PCOS that was carried out in Kashan, Iran. A sample of women with PCOS was entered into the study and completed the following questionnaires: the Hospital Anxiety and Depression Scale, the Body Image Concern Inventory (BICI), the Rosenberg's Self-Esteem Scale score, the modified polycystic ovary syndrome health-related quality of life questionnaire, the Female Sexual Function Index. Both direct and indirect relationships among clinical severity, psychological status, self-esteem, body image, and sexual function as independent predictors of HRQOL were examined using structural equation modeling (SEM) analysis. By using the SEM, we simultaneously test a number of possible hypotheses concerning the interrelations among the predictors of HRQOL in PCOS patients. In relation with severity of PCOS, reproductive history and menstrual status explained a high proportion of the variance of clinical variables (factor loading 0.37 and 0.34, respectively). The highest effect on HRQL was exerted by indirect effect of clinical factor (β = 0.90), self-esteem (β = 1.12), body image (β = 1.06), and sexual function (β = 0.26) that influenced negatively HRQOL. The infertility and menstrual domains were the most affected areas of HRQOL. In relation with sexual dysfunction, the most affected domains were desire and arousal. The highest effect of PCOS symptoms on HRQOL impairment among patients was exerted by self-esteem, body image, and sexual dysfunction. With regard to HRQOL in clinical routine, we conclude these mediating factors should be taken into consideration and adequately treated if present. © 2013 International Society for Sexual Medicine.

Region 6: Texas Adequate Letter (4/16/2010)

EPA Pesticide Factsheets

This letter from EPA to Texas Commission on Environmental Quality determined 2021 motor vehicle emission budgets for nitrogen oxides (NOx) and volatile organic compounds (VOCs) for Beaumont/Port Arthur area adequate for transportation conformity purposes

Region 10: Oregon Oakridge Adequate Letter (6/21/2017)

EPA Pesticide Factsheets

EPA approves motor vehicle emissions budget in the Oakridge-Westfir PM2.5 Attainment State Implementation Plan for the 2006 PM2.5 national ambient air quality standard, adequate for transportation conformity purposes.

Human in vivo cardiac phosphorus NMR spectroscopy at 3.0 Tesla

NASA Astrophysics Data System (ADS)

Bruner, Angela Properzio

One of the newest methods with great potential for use in clinical diagnosis of heart disease is human, cardiac, phosphorus NMR spectroscopy (cardiac p 31 MRS). Cardiac p31 MRS is able to provide quantitative, non-invasive, functional information about the myocardial energy metabolites such as pH, phosphocreatine (PCr), and adenosinetriphosphate (ATP). In addition to the use of cardiac p3l MRS for other types of cardiac problems, studies have shown that the ratio of PCr/ATP and pH are sensitive and specific markers of ischemia at the myocardial level. In human studies, typically performed at 1.5 Tesla, PCr/ATP has been relatively easy to measure but often requires long scan times to provide adequate signal-to-noise (SNR). In addition, pH which relies on identification of inorganic phosphate (Pi), has rarely been obtained. Significant improvement in the quality of cardiac p31 MRS was achieved through the use of the General Electric SIGNATM 3.0 Tesla whole body magnet, improved coil designs and optimized pulse sequences. Phantom and human studies performed on many types of imaging and spectroscopy sequences, identified breathhold gradient-echo imaging and oblique DRESS p31 spectroscopy as the best compromises between SNR, flexibility and quality localization. Both single-turn and quadrature 10-cm diameter, p31 radiofrequency coils, were tested with the quadrature coil providing greater SNR, but at a greater depth to avoid skeletal muscle contamination. Cardiac p31 MRS obtained in just 6 to 8 minutes, gated, showed both improved SNR and discernment of Pi allowing for pH measurement. A handgrip, in-magnet exerciser was designed, created and tested at 1.5 and 3.0 Tesla on volunteers and patients. In ischemic patients, this exercise was adequate to cause a repeated drop in PCr/ATP and pH with approximately eight minutes of isometric exercise at 30% maximum effort. As expected from literature, this exercise did not cause a drop in PCr/ATP for reference volunteers.

Methodological reporting quality of randomized controlled trials: A survey of seven core journals of orthopaedics from Mainland China over 5 years following the CONSORT statement.

PubMed

Zhang, J; Chen, X; Zhu, Q; Cui, J; Cao, L; Su, J

2016-11-01

In recent years, the number of randomized controlled trials (RCTs) in the field of orthopaedics is increasing in Mainland China. However, randomized controlled trials (RCTs) are inclined to bias if they lack methodological quality. Therefore, we performed a survey of RCT to assess: (1) What about the quality of RCTs in the field of orthopedics in Mainland China? (2) Whether there is difference between the core journals of the Chinese department of orthopedics and Orthopaedics Traumatology Surgery & Research (OTSR). This research aimed to evaluate the methodological reporting quality according to the CONSORT statement of randomized controlled trials (RCTs) in seven key orthopaedic journals published in Mainland China over 5 years from 2010 to 2014. All of the articles were hand researched on Chongqing VIP database between 2010 and 2014. Studies were considered eligible if the words "random", "randomly", "randomization", "randomized" were employed to describe the allocation way. Trials including animals, cadavers, trials published as abstracts and case report, trials dealing with subgroups analysis, or trials without the outcomes were excluded. In addition, eight articles selected from Orthopaedics Traumatology Surgery & Research (OTSR) between 2010 and 2014 were included in this study for comparison. The identified RCTs are analyzed using a modified version of the Consolidated Standards of Reporting Trials (CONSORT), including the sample size calculation, allocation sequence generation, allocation concealment, blinding and handling of dropouts. A total of 222 RCTs were identified in seven core orthopaedic journals. No trials reported adequate sample size calculation, 74 (33.4%) reported adequate allocation generation, 8 (3.7%) trials reported adequate allocation concealment, 18 (8.1%) trials reported adequate blinding and 16 (7.2%) trials reported handling of dropouts. In OTSR, 1 (12.5%) trial reported adequate sample size calculation, 4 (50.0%) reported adequate allocation generation, 1 (12.5%) trials reported adequate allocation concealment, 2 (25.0%) trials reported adequate blinding and 5 (62.5%) trials reported handling of dropouts. There were statistical differences as for sample size calculation and handling of dropouts between papers from Mainland China and OTSR (P<0.05). The findings of this study show that the methodological reporting quality of RCTs in seven core orthopaedic journals from the Mainland China is far from satisfaction and it needs to further improve to keep up with the standards of the CONSORT statement. Level III case control. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

MRI for appendicitis in pregnancy: is seeing believing? clinical outcomes in cases of appendix nonvisualization.

PubMed

Al-Katib, Sayf; Sokhandon, Farnoosh; Farah, Michael

2016-12-01

The primary objective of this study was to determine the clinical outcomes in cases of appendix nonvisualization with MRI in pregnant patients with suspected appendicitis and the implications of appendix nonvisualization for excluding appendicitis. Fifty-eight pregnant patients with suspected appendicitis evaluated with MRI at three centers from a single institution were retrospectively reviewed by three radiologists with varying levels of abdominal imaging experience. All scans were performed on a 1.5-Tesla Siemens unit. Cases were evaluated for diagnostic quality, visualization of the appendix, presence of appendicitis, and alternate diagnoses. Clinical outcomes were gathered from the electronic medical record. Of the 58 patients who underwent MRI for suspected appendicitis, 50 cases were considered adequate diagnostic quality by all three radiologists. The rate of appendix visualization among the three radiologists ranged from 60 to 76% (p = 0.44). The appendix was nonvisualized by at least one of the three radiologists in 25 cases (50%). Of these, none had a final diagnosis of appendicitis including one patient who underwent appendectomy. MRI suggested an alternate diagnosis in 6 (24%) patients with appendix nonvisualization. For the three reviewers, the agreement level on whether or not the appendix was visualized on the MRI had a Light's kappa value of 0.526, indicating a "moderate" level of agreement (p value < 0.01). Despite only moderate level of interobserver agreement for appendix visualization, appendix nonvisualization on MRI in pregnant patients with suspected appendicitis confers a significant reduction in the risk of appendicitis compared to all comers as long as the study is adequate diagnostic quality and there are no secondary signs of appendicitis present.

Right parasternal imaging: an underutilized echocardiographic technique.

PubMed

Marcella, C P; Johnson, L E

1993-01-01

If the echocardiographer uses only standard imaging planes, he or she may fail to obtain vital information about the aorta, atrial septum, superior and inferior vena cavae, and the coronary arteries. The evaluation of caval-to-systemic venous atrial connections (Senning or Mustard) in transposition of the great arteries of systemic vena caval or right atrial-to-pulmonary anastomosis (Fontan) in tricuspid atresia and single ventricle may not be adequately seen when only the standard left parasternal, apical, subcostal, and suprasternal imaging planes are used. Therefore, the use of the right parasternal imaging plane may help to provide crucial information regarding these areas when the standard views are unable to delineate them adequately. The right parasternal window is an additional echocardiographic window that should become part of a complete echocardiographic examination.

Moving beyond quality control in diagnostic radiology and the role of the clinically qualified medical physicist.

PubMed

Delis, H; Christaki, K; Healy, B; Loreti, G; Poli, G L; Toroi, P; Meghzifene, A

2017-09-01

Quality control (QC), according to ISO definitions, represents the most basic level of quality. It is considered to be the snapshot of the performance or the characteristics of a product or service, in order to verify that it complies with the requirements. Although it is usually believed that "the role of medical physicists in Diagnostic Radiology is QC", this, not only limits the contribution of medical physicists, but is also no longer adequate to meet the needs of Diagnostic Radiology in terms of Quality. In order to assure quality practices more organized activities and efforts are required in the modern era of diagnostic radiology. The complete system of QC is just one element of a comprehensive quality assurance (QA) program that aims at ensuring that the requirements of quality of a product or service will consistently be fulfilled. A comprehensive Quality system, starts even before the procurement of any equipment, as the need analysis and the development of specifications are important components under the QA framework. Further expanding this framework of QA, a comprehensive Quality Management System can provide additional benefits to a Diagnostic Radiology service. Harmonized policies and procedures and elements such as mission statement or job descriptions can provide clarity and consistency in the services provided, enhancing the outcome and representing a solid platform for quality improvement. The International Atomic Energy Agency (IAEA) promotes this comprehensive quality approach in diagnostic imaging and especially supports the field of comprehensive clinical audits as a tool for quality improvement. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Ultra high resolution imaging of the human head at 8 tesla: 2K x 2K for Y2K.

PubMed

Robitaille, P M; Abduljalil, A M; Kangarlu, A

2000-01-01

To acquire ultra high resolution MRI images of the human brain at 8 Tesla within a clinically acceptable time frame. Gradient echo images were acquired from the human head of normal subjects using a transverse electromagnetic resonator operating in quadrature and tuned to 340 MHz. In each study, a group of six images was obtained containing a total of 208 MB of unprocessed information. Typical acquisition parameters were as follows: matrix = 2,000 x 2,000, field of view = 20 cm, slice thickness = 2 mm, number of excitations (NEX) = 1, flip angle = 45 degrees, TR = 750 ms, TE = 17 ms, receiver bandwidth = 69.4 kHz. This resulted in a total scan time of 23 minutes, an in-plane resolution of 100 microm, and a pixel volume of 0.02 mm3. The ultra high resolution images acquired in this study represent more than a 50-fold increase in in-plane resolution relative to conventional 256 x 256 images obtained with a 20 cm field of view and a 5 mm slice thickness. Nonetheless, the ultra high resolution images could be acquired both with adequate image quality and signal to noise. They revealed numerous small venous structures throughout the image plane and provided reasonable delineation between gray and white matter. The elevated signal-to-noise ratio observed in ultra high field magnetic resonance imaging can be utilized to acquire images with a level of resolution approaching the histological level under in vivo conditions. However, brain motion is likely to degrade the useful resolution. This situation may be remedied in part with cardiac gating. Nonetheless, these images represent a significant advance in our ability to examine small anatomical features with noninvasive imaging methods.

Current external beam radiation therapy quality assurance guidance: does it meet the challenges of emerging image-guided technologies?

PubMed

Palta, Jatinder R; Liu, Chihray; Li, Jonathan G

2008-01-01

The traditional prescriptive quality assurance (QA) programs that attempt to ensure the safety and reliability of traditional external beam radiation therapy are limited in their applicability to such advanced radiation therapy techniques as three-dimensional conformal radiation therapy, intensity-modulated radiation therapy, inverse treatment planning, stereotactic radiosurgery/radiotherapy, and image-guided radiation therapy. The conventional QA paradigm, illustrated by the American Association of Physicists in Medicine Radiation Therapy Committee Task Group 40 (TG-40) report, consists of developing a consensus menu of tests and device performance specifications from a generic process model that is assumed to apply to all clinical applications of the device. The complexity, variation in practice patterns, and level of automation of high-technology radiotherapy renders this "one-size-fits-all" prescriptive QA paradigm ineffective or cost prohibitive if the high-probability error pathways of all possible clinical applications of the device are to be covered. The current approaches to developing comprehensive prescriptive QA protocols can be prohibitively time consuming and cost ineffective and may sometimes fail to adequately safeguard patients. It therefore is important to evaluate more formal error mitigation and process analysis methods of industrial engineering to more optimally focus available QA resources on process components that have a significant likelihood of compromising patient safety or treatment outcomes.

Automated classification of bone marrow cells in microscopic images for diagnosis of leukemia: a comparison of two classification schemes with respect to the segmentation quality

NASA Astrophysics Data System (ADS)

Krappe, Sebastian; Benz, Michaela; Wittenberg, Thomas; Haferlach, Torsten; Münzenmayer, Christian

2015-03-01

The morphological analysis of bone marrow smears is fundamental for the diagnosis of leukemia. Currently, the counting and classification of the different types of bone marrow cells is done manually with the use of bright field microscope. This is a time consuming, partly subjective and tedious process. Furthermore, repeated examinations of a slide yield intra- and inter-observer variances. For this reason an automation of morphological bone marrow analysis is pursued. This analysis comprises several steps: image acquisition and smear detection, cell localization and segmentation, feature extraction and cell classification. The automated classification of bone marrow cells is depending on the automated cell segmentation and the choice of adequate features extracted from different parts of the cell. In this work we focus on the evaluation of support vector machines (SVMs) and random forests (RFs) for the differentiation of bone marrow cells in 16 different classes, including immature and abnormal cell classes. Data sets of different segmentation quality are used to test the two approaches. Automated solutions for the morphological analysis for bone marrow smears could use such a classifier to pre-classify bone marrow cells and thereby shortening the examination duration.

The WIYN One Degree Imager - Status and Performance

NASA Astrophysics Data System (ADS)

Boroson, Todd A.

2013-06-01

A preliminary version of the WIYN One Degree Imager (ODI) has been commissioned and put into scientific operation. ODI was designed to take advantage of the excellent image quality and wide field of view of the WIYN 3.5m telescope. It will do this by covering a one square degree focal plane with orthogonal transfer array (OTA) detectors, which have the capability to correct for image motion during the exposure in regions approximately the size of the isokinetic patch. The partial ODI (pODI) differs from the complete ODI in two ways - only 13 of the 64 OTAs populate the focal plane, and only coherent image motion correction is enabled. However, this implementation has allowed the commissioning of the instrument with all subsystems except the additional detectors in place. The 13 OTAs are configured as a 24 X 24 arcminute “science field”, plus 4 outer OTAs, allowing the sampling of all radii within the one square degree field. pODI is now in use for science observations as we prepare to upgrade the focal plane. The performance of pODI is excellent. Image quality is site seeing limited, and, on good seeing nights, we can achieve images around 0.4 arcsec FWHM over the entire field. The guide signal, from selected regions in the outer OTAs, can be passed to the telescope exclusively, or the high frequency component can be applied as a global shift to the OTAs. We are still in the process of characterizing the gains from this coherent correction, but the detectors perform well in this mode. Data are immediately transferred to an archive at Indiana University, where they are pipeline-processed to remove instrumental signature. The OTA detectors perform adequately in terms of read noise, full well, sensitivity, and dark current. They show 2 anomalies: (1) regions in the circuitry outside the imaging area glow under certain circumstances, and (2) a low level degradation of charge transfer efficiency is present between the imaging area and the serial registers. We have found ways to address both of these effects in operation, calibration, and post-processing, and the instrument is producing valuable scientific observations.

Region 10: Idaho Northern Ada County Adequate Letter (6/21/2013)

EPA Pesticide Factsheets

EPA approves motor vehicle emissions budget in the Northern Ada County PM10 State Implementation Plan, Maintenance Plan: Ten-Year Update for PM10 national ambient air quality standard, adequate for transportation conformity purposes.

First Steps Toward Ultrasound-Based Motion Compensation for Imaging and Therapy: Calibration with an Optical System and 4D PET Imaging

PubMed Central

Schwaab, Julia; Kurz, Christopher; Sarti, Cristina; Bongers, André; Schoenahl, Frédéric; Bert, Christoph; Debus, Jürgen; Parodi, Katia; Jenne, Jürgen Walter

2015-01-01

Target motion, particularly in the abdomen, due to respiration or patient movement is still a challenge in many diagnostic and therapeutic processes. Hence, methods to detect and compensate this motion are required. Diagnostic ultrasound (US) represents a non-invasive and dose-free alternative to fluoroscopy, providing more information about internal target motion than respiration belt or optical tracking. The goal of this project is to develop an US-based motion tracking for real-time motion correction in radiation therapy and diagnostic imaging, notably in 4D positron emission tomography (PET). In this work, a workflow is established to enable the transformation of US tracking data to the coordinates of the treatment delivery or imaging system – even if the US probe is moving due to respiration. It is shown that the US tracking signal is equally adequate for 4D PET image reconstruction as the clinically used respiration belt and provides additional opportunities in this concern. Furthermore, it is demonstrated that the US probe being within the PET field of view generally has no relevant influence on the image quality. The accuracy and precision of all the steps in the calibration workflow for US tracking-based 4D PET imaging are found to be in an acceptable range for clinical implementation. Eventually, we show in vitro that an US-based motion tracking in absolute room coordinates with a moving US transducer is feasible. PMID:26649277

Optimal detection pinhole for lowering speckle noise while maintaining adequate optical sectioning in confocal reflectance microscopes

PubMed Central

Rajadhyaksha, Milind

2012-01-01

Abstract. Coherent speckle influences the resulting image when narrow spectral line-width and single spatial mode illumination are used, though these are the same light-source properties that provide the best radiance-to-cost ratio. However, a suitable size of the detection pinhole can be chosen to maintain adequate optical sectioning while making the probability density of the speckle noise more normal and reducing its effect. The result is a qualitatively better image with improved contrast, which is easier to read. With theoretical statistics and experimental results, we show that the detection pinhole size is a fundamental parameter for designing imaging systems for use in turbid media. PMID:23224184

Fully automated registration of first-pass myocardial perfusion MRI using independent component analysis.

PubMed

Milles, J; van der Geest, R J; Jerosch-Herold, M; Reiber, J H C; Lelieveldt, B P F

2007-01-01

This paper presents a novel method for registration of cardiac perfusion MRI. The presented method successfully corrects for breathing motion without any manual interaction using Independent Component Analysis to extract physiologically relevant features together with their time-intensity behavior. A time-varying reference image mimicking intensity changes in the data of interest is computed based on the results of ICA, and used to compute the displacement caused by breathing for each frame. Qualitative and quantitative validation of the method is carried out using 46 clinical quality, short-axis, perfusion MR datasets comprising 100 images each. Validation experiments showed a reduction of the average LV motion from 1.26+/-0.87 to 0.64+/-0.46 pixels. Time-intensity curves are also improved after registration with an average error reduced from 2.65+/-7.89% to 0.87+/-3.88% between registered data and manual gold standard. We conclude that this fully automatic ICA-based method shows an excellent accuracy, robustness and computation speed, adequate for use in a clinical environment.

Real-time terahertz digital holography with a quantum cascade laser

PubMed Central

Locatelli, Massimiliano; Ravaro, Marco; Bartalini, Saverio; Consolino, Luigi; Vitiello, Miriam S.; Cicchi, Riccardo; Pavone, Francesco; De Natale, Paolo

2015-01-01

Coherent imaging in the THz range promises to exploit the peculiar capabilities of these wavelengths to penetrate common materials like plastics, ceramics, paper or clothes with potential breakthroughs in non-destructive inspection and quality control, homeland security and biomedical applications. Up to now, however, THz coherent imaging has been limited by time-consuming raster scanning, point-like detection schemes and by the lack of adequate coherent sources. Here, we demonstrate real-time digital holography (DH) at THz frequencies exploiting the high spectral purity and the mW output power of a quantum cascade laser combined with the high sensitivity and resolution of a microbolometric array. We show that, in a one-shot exposure, phase and amplitude information of whole samples, either in reflection or in transmission, can be recorded. Furthermore, a 200 times reduced sensitivity to mechanical vibrations and a significantly enlarged field of view are observed, as compared to DH in the visible range. These properties of THz DH enable unprecedented holographic recording of real world dynamic scenes. PMID:26315647

Image-guided intervention in the human bile duct using scanning fiber endoscope system

NASA Astrophysics Data System (ADS)

Seibel, Eric J.; Jo, Javier A.; Melville, C. David; Johnston, Richard S.; Naumann, Christopher R.; Saunders, Michael D.

2012-01-01

Bile duct cancers are increasing in frequency while being difficult to diagnose. Currently available endoscopic imaging devices used in the biliary tree are low resolution with poor image quality, leading to inadequate evaluation of indeterminate biliary strictures. However, a new ultrathin and flexible cholangioscope system has been successfully demonstrated in a human subject. This mini-cholangioscope system uses a scanning fiber endoscope (SFE) as a forward-imaging guidewire, dimensions of 1.2-mm diameter and 3-m length. Full color video (500-line resolution at 30Hz) is the standard SFE imaging mode using spiral scanning of red, green, and blue laser light at low power. Image-guided operation of the biopsy forceps was demonstrated in healthy human bile ducts with and without saline flushing. The laser-based video imaging can be switched to various modes to enhance tissue markers of disease, such as widefield fluorescence and enhanced spectral imaging. In parallel work, biochemical discrimination of tissue health in pig bile duct has been accomplished using fiberoptic delivery of pulsed UV illumination and time-resolved autofluorescence spectroscopic measurements. Implementation of time-resolved fluorescence spectroscopy for biochemical assessment of the bile duct wall is being done through a secondary endoscopic channel. Preliminary results indicate that adequate SNR levels (> 30 dB) can be achieved through a 50 micron fiber, which could serve as an optical biopsy probe. The SFE is an ideal mini-cholangioscope for integration of both tissue and molecular specific image contrast in the future. This will provide the physician with unprecedented abilities to target biopsy locations and perform endoscopically-guided therapies.

Factors Contributing to University Image: The Postgraduate Students' Points of View

ERIC Educational Resources Information Center

Aghaz, Asal; Hashemi, Amin; Atashgah, Maryam S. Sharifi

2015-01-01

Despite several studies having been conducted to examine organizational image from a business perspective, there has not been adequate research in the area of perceived image in nonprofit organizations such as universities. Thus, the purpose of this study was to examine the factors contributing to university image, from the postgraduate students'…

Cone-beam computed tomography in the assessment of periapical lesions in endodontically treated teeth

PubMed Central

Gambarini, Gianluca; Piasecki, Lucila; Miccoli, Gabriele; Gaimari, Gianfranco; Nardo, Dario Di; Testarelli, Luca

2018-01-01

Objective: This study aimed to evaluate the relationship between the quality of the coronal restoration and the root canal filling on the periapical status of endodontically treated teeth using CBCT. Materials and Methods: CBCT data were obtained from the records of patients who deny any dental treatment in the 2 years prior to the CBCT examination. CBCT images (90 kVp and 7 mA, exposure time of 23 s, and a voxel size of 0.2 mm, with a field of view of 13 cm × 13 cm) of 1011 endodontically treated teeth were observed. A score was given to the quality of the root filling and the quality of the coronal restoration. Statistical Analysis Used: Data were statistically analyzed to correlate the periapical status with gender, dental group. and quality of endodontic treatment and restoration (Chi-square test with a significance level of P < 0.001). Results: Absence of periapical periodontitis was found in 54.9% of the cases. The periapical outcome was not related to gender or dental group (P > 0.05). A statistically significant factor (Chi-square test, P < 0.0001) resulted when different qualities of sealing were compared. Conclusions: CBCT showed that high-quality root canal treatments followed by an adequate coronal sealing restoration avoid the presence of periapical periodontitis in time. PMID:29657539

Subcutaneous Tissue Thickness is an Independent Predictor of Image Noise in Cardiac CT

PubMed Central

Staniak, Henrique Lane; Sharovsky, Rodolfo; Pereira, Alexandre Costa; de Castro, Cláudio Campi; Benseñor, Isabela M.; Lotufo, Paulo A.; Bittencourt, Márcio Sommer

2014-01-01

Background Few data on the definition of simple robust parameters to predict image noise in cardiac computed tomography (CT) exist. Objectives To evaluate the value of a simple measure of subcutaneous tissue as a predictor of image noise in cardiac CT. Methods 86 patients underwent prospective ECG-gated coronary computed tomographic angiography (CTA) and coronary calcium scoring (CAC) with 120 kV and 150 mA. The image quality was objectively measured by the image noise in the aorta in the cardiac CTA, and low noise was defined as noise < 30HU. The chest anteroposterior diameter and lateral width, the image noise in the aorta and the skin-sternum (SS) thickness were measured as predictors of cardiac CTA noise. The association of the predictors and image noise was performed by using Pearson correlation. Results The mean radiation dose was 3.5 ± 1.5 mSv. The mean image noise in CT was 36.3 ± 8.5 HU, and the mean image noise in non-contrast scan was 17.7 ± 4.4 HU. All predictors were independently associated with cardiac CTA noise. The best predictors were SS thickness, with a correlation of 0.70 (p < 0.001), and noise in the non-contrast images, with a correlation of 0.73 (p < 0.001). When evaluating the ability to predict low image noise, the areas under the ROC curve for the non-contrast noise and for the SS thickness were 0.837 and 0.864, respectively. Conclusion Both SS thickness and CAC noise are simple accurate predictors of cardiac CTA image noise. Those parameters can be incorporated in standard CT protocols to adequately adjust radiation exposure. PMID:24173136

A Metric and Workflow for Quality Control in the Analysis of Heterogeneity in Phenotypic Profiles and Screens

PubMed Central

Gough, Albert; Shun, Tongying; Taylor, D. Lansing; Schurdak, Mark

2016-01-01

Heterogeneity is well recognized as a common property of cellular systems that impacts biomedical research and the development of therapeutics and diagnostics. Several studies have shown that analysis of heterogeneity: gives insight into mechanisms of action of perturbagens; can be used to predict optimal combination therapies; and to quantify heterogeneity in tumors where heterogeneity is believed to be associated with adaptation and resistance. Cytometry methods including high content screening (HCS), high throughput microscopy, flow cytometry, mass spec imaging and digital pathology capture cell level data for populations of cells. However it is often assumed that the population response is normally distributed and therefore that the average adequately describes the results. A deeper understanding of the results of the measurements and more effective comparison of perturbagen effects requires analysis that takes into account the distribution of the measurements, i.e. the heterogeneity. However, the reproducibility of heterogeneous data collected on different days, and in different plates/slides has not previously been evaluated. Here we show that conventional assay quality metrics alone are not adequate for quality control of the heterogeneity in the data. To address this need, we demonstrate the use of the Kolmogorov-Smirnov statistic as a metric for monitoring the reproducibility of heterogeneity in an SAR screen, describe a workflow for quality control in heterogeneity analysis. One major challenge in high throughput biology is the evaluation and interpretation of heterogeneity in thousands of samples, such as compounds in a cell-based screen. In this study we also demonstrate that three heterogeneity indices previously reported, capture the shapes of the distributions and provide a means to filter and browse big data sets of cellular distributions in order to compare and identify distributions of interest. These metrics and methods are presented as a workflow for analysis of heterogeneity in large scale biology projects. PMID:26476369

State Implementation Plans (SIP): Submissions that EPA has Found Adequate or Inadequate

EPA Pesticide Factsheets

EPA/OTAQ’s State and Local Transportation Resources are for air quality and transportation government and community leaders. Information on state implementation plans (SIPs) that EPA has found either adequate or inadequate is provided here.

A quality analysis of clinical anaesthesia study protocols from the Chinese clinical trials registry according to the SPIRIT statement

PubMed Central

Yang, Lei; Chen, Shouming; Yang, Di; Li, Jiajin; Wu, Taixiang; Zuo, Yunxia

2018-01-01

Objective To learn about the overall quality of clinical anaesthesia study protocols from the Chinese Clinical Trials Registry and to discuss the way to improve study protocol quality. Methods We defined completeness of each sub-item in SPIRIT as N/A (not applicable) or with a score of 0, 1, or 2. For each protocol, we calculated the proportion of adequately reported items (score = 2 and N/A) and unreported items (score = 0). Protocol quality was determined according to the proportion of reported items, with values >50% indicating high quality. Protocol quality was determined according to the proportion of reported items. For each sub-item in SPIRIT, we calculated the adequately reported rate (percentage of all protocols with score 2 and NA on one sub-item) as well as the unreported rate (percentage of all protocols with score 0 on one sub-item). Results Total 126 study protocols were available for assessment. Among these, 88.1% were assessed as being of low quality. By comparison, the percentage of low-quality protocols was 88.9% after the publication of the SPIRIT statement. Among the 51 SPIRIT sub-items, 18 sub-items had an unreported rate above 90% while 16 had a higher adequately reported rate than an unreported rate. Conclusions The overall quality of clinical anaesthesia study protocols registered in the ChiCTR was poor. A mandatory protocol upload and self-check based on the SPIRIT statement during the trial registration process may improve protocol quality in the future. PMID:29872509

Process monitoring of additive manufacturing by using optical tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zenzinger, Guenter, E-mail: guenter.zenzinger@mtu.de, E-mail: alexander.ladewig@mtu.de; Bamberg, Joachim, E-mail: guenter.zenzinger@mtu.de, E-mail: alexander.ladewig@mtu.de; Ladewig, Alexander, E-mail: guenter.zenzinger@mtu.de, E-mail: alexander.ladewig@mtu.de

2015-03-31

Parts fabricated by means of additive manufacturing are usually of complex shape and owing to the fabrication procedure by using selective laser melting (SLM), potential defects and inaccuracies are often very small in lateral size. Therefore, an adequate quality inspection of such parts is rather challenging, while non-destructive-techniques (NDT) are difficult to realize, but considerable efforts are necessary in order to ensure the quality of SLM-parts especially used for aerospace components. Thus, MTU Aero Engines is currently focusing on the development of an Online Process Control system which monitors and documents the complete welding process during the SLM fabrication procedure.more » A high-resolution camera system is used to obtain images, from which tomographic data for a 3dim analysis of SLM-parts are processed. From the analysis, structural irregularities and structural disorder resulting from any possible erroneous melting process become visible and may be allocated anywhere within the 3dim structure. Results of our optical tomography (OT) method as obtained on real defects are presented.« less

Preliminary results on the various U.V. straylight sources for the VWFC onboard SL 1. [Very Wide Field Camera

NASA Technical Reports Server (NTRS)

Viton, M.; Courtes, G.; Sivan, J. P.; Decher, R.; Gary, A.

1985-01-01

Technical difficulties encountered using the Very Wide Field Camera (VWFC) during the Spacelab 1 Shuttle mission are reported. The VWFC is a wide low resolution (5 arcmin half-half width) photographic camera, capable of operating in both spectrometric and photometric modes. The bandpasses of the photometric mode of the VWFC are defined by three Al + MgF2 interference filters. A piggy-back spectrograph attached to the VWFC was used for observations in the spectrometric mode. A total of 48 astronomical frames were obtained using the VWFC, of which only 20 were considered to be of adequate quality for astronomical data processing. Preliminary analysis of the 28 poor-quality images revealed the following possible defects in the VWFC: darkness in the spacing frames, twilight/dawn UV straylight, and internal UV straylight. Improvements in the VWFC astronomical data processing scheme are expected to help identify and eliminate UV straylight sources in the future.

Automatic page layout using genetic algorithms for electronic albuming

NASA Astrophysics Data System (ADS)

Geigel, Joe; Loui, Alexander C. P.

2000-12-01

In this paper, we describe a flexible system for automatic page layout that makes use of genetic algorithms for albuming applications. The system is divided into two modules, a page creator module which is responsible for distributing images amongst various album pages, and an image placement module which positions images on individual pages. Final page layouts are specified in a textual form using XML for printing or viewing over the Internet. The system makes use of genetic algorithms, a class of search and optimization algorithms that are based on the concepts of biological evolution, for generating solutions with fitness based on graphic design preferences supplied by the user. The genetic page layout algorithm has been incorporated into a web-based prototype system for interactive page layout over the Internet. The prototype system is built using client-server architecture and is implemented in java. The system described in this paper has demonstrated the feasibility of using genetic algorithms for automated page layout in albuming and web-based imaging applications. We believe that the system adequately proves the validity of the concept, providing creative layouts in a reasonable number of iterations. By optimizing the layout parameters of the fitness function, we hope to further improve the quality of the final layout in terms of user preference and computation speed.

Factors to keep in mind when introducing virtual microscopy.

PubMed

Glatz-Krieger, Katharina; Spornitz, Udo; Spatz, Alain; Mihatsch, Michael J; Glatz, Dieter

2006-03-01

Digitization of glass slides and delivery of so-called virtual slides (VS) emulating a real microscope over the Internet have become reality due to recent improvements in technology. We have implemented a virtual microscope for instruction of medical students and for continuing medical education. Up to 30,000 images per slide are captured using a microscope with an automated stage. The images are post-processed and then served by a plain hypertext transfer protocol (http)-server. A virtual slide client (vMic) based on Macromedia's Flash MX, a highly accepted technology available on every modern Web browser, has been developed. All necessary virtual slide parameters are stored in an XML file together with the image. Evaluation of the courses by questionnaire indicated that most students and many but not all pathologists regard virtual slides as an adequate replacement for traditional slides. All our virtual slides are publicly accessible over the World Wide Web (WWW) at http://vmic.unibas.ch . Recently, several commercially available virtual slide acquisition systems (VSAS) have been developed that use various technologies to acquire and distribute virtual slides. These systems differ in speed, image quality, compatibility, viewer functionalities and price. This paper gives an overview of the factors to keep in mind when introducing virtual microscopy.

Arnheim's Gestalt theory of visual balance: Examining the compositional structure of art photographs and abstract images

PubMed Central

McManus, I C; Stöver, Katharina; Kim, Do

2011-01-01

In Art and Visual Perception, Rudolf Arnheim, following on from Denman Ross's A Theory of Pure Design, proposed a Gestalt theory of visual composition. The current paper assesses a physicalist interpretation of Arnheim's theory, calculating an image's centre of mass (CoM). Three types of data are used: a large, representative collection of art photographs of recognised quality; croppings by experts and non-experts of photographs; and Ross and Arnheim's procedure of placing a frame around objects such as Arnheim's two black disks. Compared with control images, the CoM of art photographs was closer to an axis (horizontal, vertical, or diagonal), as was the case for photographic croppings. However, stronger, within-image, paired comparison studies, comparing art photographs with the CoM moved on or off an axis (the ‘gamma-ramp study’), or comparing adjacent croppings on or off an axis (the ‘spider-web study’), showed no support for the Arnheim–Ross theory. Finally, studies moving a frame around two disks, of different size, greyness, or background, did not support Arnheim's Gestalt theory. Although the detailed results did not support the Arnheim–Ross theory, several significant results were found which clearly require explanation by any adequate theory of the aesthetics of visual composition. PMID:23145250

Arnheim's Gestalt theory of visual balance: Examining the compositional structure of art photographs and abstract images.

PubMed

McManus, I C; Stöver, Katharina; Kim, Do

2011-01-01

In Art and Visual Perception, Rudolf Arnheim, following on from Denman Ross's A Theory of Pure Design, proposed a Gestalt theory of visual composition. The current paper assesses a physicalist interpretation of Arnheim's theory, calculating an image's centre of mass (CoM). Three types of data are used: a large, representative collection of art photographs of recognised quality; croppings by experts and non-experts of photographs; and Ross and Arnheim's procedure of placing a frame around objects such as Arnheim's two black disks. Compared with control images, the CoM of art photographs was closer to an axis (horizontal, vertical, or diagonal), as was the case for photographic croppings. However, stronger, within-image, paired comparison studies, comparing art photographs with the CoM moved on or off an axis (the 'gamma-ramp study'), or comparing adjacent croppings on or off an axis (the 'spider-web study'), showed no support for the Arnheim-Ross theory. Finally, studies moving a frame around two disks, of different size, greyness, or background, did not support Arnheim's Gestalt theory. Although the detailed results did not support the Arnheim-Ross theory, several significant results were found which clearly require explanation by any adequate theory of the aesthetics of visual composition.

Progress Implementing a Model-Based Iterative Reconstruction Algorithm for Ultrasound Imaging of Thick Concrete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Almansouri, Hani; Johnson, Christi R; Clayton, Dwight A

All commercial nuclear power plants (NPPs) in the United States contain concrete structures. These structures provide important foundation, support, shielding, and containment functions. Identification and management of aging and the degradation of concrete structures is fundamental to the proposed long-term operation of NPPs. Concrete structures in NPPs are often inaccessible and contain large volumes of massively thick concrete. While acoustic imaging using the synthetic aperture focusing technique (SAFT) works adequately well for thin specimens of concrete such as concrete transportation structures, enhancements are needed for heavily reinforced, thick concrete. We argue that image reconstruction quality for acoustic imaging in thickmore » concrete could be improved with Model-Based Iterative Reconstruction (MBIR) techniques. MBIR works by designing a probabilistic model for the measurements (forward model) and a probabilistic model for the object (prior model). Both models are used to formulate an objective function (cost function). The final step in MBIR is to optimize the cost function. Previously, we have demonstrated a first implementation of MBIR for an ultrasonic transducer array system. The original forward model has been upgraded to account for direct arrival signal. Updates to the forward model will be documented and the new algorithm will be assessed with synthetic and empirical samples.« less

Progress implementing a model-based iterative reconstruction algorithm for ultrasound imaging of thick concrete

NASA Astrophysics Data System (ADS)

Almansouri, Hani; Johnson, Christi; Clayton, Dwight; Polsky, Yarom; Bouman, Charles; Santos-Villalobos, Hector

2017-02-01

All commercial nuclear power plants (NPPs) in the United States contain concrete structures. These structures provide important foundation, support, shielding, and containment functions. Identification and management of aging and the degradation of concrete structures is fundamental to the proposed long-term operation of NPPs. Concrete structures in NPPs are often inaccessible and contain large volumes of massively thick concrete. While acoustic imaging using the synthetic aperture focusing technique (SAFT) works adequately well for thin specimens of concrete such as concrete transportation structures, enhancements are needed for heavily reinforced, thick concrete. We argue that image reconstruction quality for acoustic imaging in thick concrete could be improved with Model-Based Iterative Reconstruction (MBIR) techniques. MBIR works by designing a probabilistic model for the measurements (forward model) and a probabilistic model for the object (prior model). Both models are used to formulate an objective function (cost function). The final step in MBIR is to optimize the cost function. Previously, we have demonstrated a first implementation of MBIR for an ultrasonic transducer array system. The original forward model has been upgraded to account for direct arrival signal. Updates to the forward model will be documented and the new algorithm will be assessed with synthetic and empirical samples.

Simulation of breast compression in mammography using finite element analysis: A preliminary study

NASA Astrophysics Data System (ADS)

Liu, Yan-Lin; Liu, Pei-Yuan; Huang, Mei-Lan; Hsu, Jui-Ting; Han, Ruo-Ping; Wu, Jay

2017-11-01

Adequate compression during mammography lowers the absorbed dose in the breast and improves the image quality. The compressed breast thickness (CBT) is affected by various factors, such as breast volume, glandularity, and compression force. In this study, we used the finite element analysis to simulate breast compression and deformation and validated the simulated CBT with clinical mammography results. Image data from ten subjects who had undergone mammography screening and breast magnetic resonance imaging (MRI) were collected, and their breast models were created according to the MR images. The non-linear tissue deformation under 10-16 daN in the cranial-caudal direction was simulated. When the clinical compression force was used, the simulated CBT ranged from 2.34 to 5.90 cm. The absolute difference between the simulated CBT and the clinically measured CBT ranged from 0.5 to 7.1 mm. The simulated CBT had a strong positive linear relationship to breast volume and a weak negative correlation to glandularity. The average simulated CBT under 10, 12, 14, and 16 daN was 5.68, 5.12, 4.67, and 4.25 cm, respectively. Through this study, the relationships between CBT, breast volume, glandularity, and compression force are provided for use in clinical mammography.

Wideband late gadolinium enhanced magnetic resonance imaging for imaging myocardial scar without image artefacts induced by implantable cardioverter-defibrillator: a feasibility study at 3 T

PubMed Central

Ranjan, Ravi; McGann, Christopher J.; Jeong, Eun-Kee; Hong, KyungPyo; Kholmovski, Eugene G.; Blauer, Josh; Wilson, Brent D.; Marrouche, Nassir F.; Kim, Daniel

2015-01-01

Aim Late gadolinium enhanced (LGE) magnetic resonance imaging (MRI) is a useful tool for facilitating ventricular tachycardia (VT) ablation. Unfortunately, most VT ablation candidates often have prophylactic implantable cardioverter-defibrillator (ICD) and do not undergo cardiac MRI largely due to image artefacts generated by ICD. A prior study has reported success of ‘wideband’ LGE MRI for imaging myocardial scar without image artefacts induced by ICD at 1.5T. The purpose of this study was to widen the availability of wideband LGE MRI to 3T, since it has the potential to achieve higher spatial resolution than 1.5T. Methods and results We compared the performance of standard and wideband LGE MRI pulse sequences in phantoms and canines with myocardial lesions created by radiofrequency ablation. Standard LGE MRI produced image artefacts induced by ICD and 49% accuracy in detecting 97 myocardial scars examined in this study, whereas wideband LGE MRI produced artefact-free images and 94% accuracy in detecting scars. The mean image quality score (1 = nondiagnostic, 2 = poor, 3 = adequate, 4 = good, 5 = excellent) was significantly (P < 0.001) higher for wideband (3.7 ± 0.8) than for standard LGE MRI (2.1 ± 0.7). The mean artefact level score (1 = minimal, 2 = mild, 3 = moderate, 4 = severe, 5 = nondiagnostic) was significantly (P < 0.001) lower for wideband (2.1 ± 0.8) than for standard LGE MRI (4.0 ± 0.6). Wideband LGE MRI agreed better with gross pathology than standard LGE MRI. Conclusion This study demonstrates the feasibility of wideband LGE MRI for suppression of image artefacts induced by ICD at 3T. PMID:25336666

[Dispatchers' impressions and actual quality of cardiopulmonary resuscitation during telephone-assisted bystander cardiopulmonary resuscitation: a pooled analysis of 94 simulated, manikin-based scenarios].

PubMed

van Tulder, Raphael; Roth, Dominik; Laggner, Roberta; Krammel, Mario; Schriefl, Christoph; Kienbacher, Calvin; Novosad, Heinz; Chwojka, Constantin Christof; Sterz, Fritz; Havel, Christof; Schreiber, Wolfgang; Herkner, Harald

2017-02-01

The quality of telephone-assisted cardiopulmonary resuscitation (CPR) needs improvement. This study investigates whether a dispatchers' perception is an adequate measure of the actual quality of CPR provided by laypersons. Individual participant data from 3 randomized simulation trials, with identical methodology but different interventions, were combined for this analysis. Professional dispatchers gave telephone assistance to laypersons, who each provided 10 minutes of CPR on a manikin. Dispatchers were requested to classify the quality of providers' CPR as adequate or inadequate. Based on actual readings from manikins we classified providers' performance as adequate at 5-6 cm for depth and 100-120 compressions per minute (cpm) for rate. We calculated metrics of dispatcher accuracy. Six dispatchers rated the performance of 94 laypersons (38 women [42%]) with a mean (SD) age of 37 (14) years. In 905 analyzed minutes of telephone-assisted CPR, the mean compression depth and rate was 41 (13) mm and 98 (24) cpm, respectively. Analysis of dispatchers' diagnostic test accuracy for adequate compression depth yielded a sensitivity of 65% (95 CI 36%-95%) and specificity of 42% (95% CI, 32%-53%). Analysis of their assessment of adequate compression rate yielded a sensitivity of 75% (95% CI, 64%-86%) and specificity of 42% (95% CI, 32%-52%). Although dispatchers always underestimated the actual values of CPR parameters, the female dispatchers evaluations were less inaccurate than the evaluations of make dispatchers; the dispatchers overall (males and females together) underestimated the adequacy of female laypersons' CPR performance to a greater degree than female dispatchers did. The ability of dispatchers to estimate the quality of telephone-assisted CPR is limited. Dispatchers estimates of CPR adequacy needs to be studied further in order to find ways that telephone-assisted CPR might be improved.

Wide-Field-of-View Millimeter-Wave Telescope Design with Ultra-Low Cross-Polarization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernacki, Bruce E.; Kelly, James F.; Sheen, David M.

2012-05-01

As millimeter-wave arrays become available, off-axis imaging performance of the fore optics increases in importance due to the relatively large physical extent of the arrays. Typically, simple optical telescope designs are adapted to millimeter-wave imaging but single-mirror spherical or classic conic designs cannot deliver adequate image quality except near the optical axis. Since most millimeter-wave designs are quasi-optical, optical ray tracing and commercial design software can be used to optimize designs to improve off-axis imaging as well as minimize cross-polarization. Methods that obey the Dragone-Mizuguchi condition for the design of reflective millimeter-wave telescopes with low cross-polarization also provide additional degreesmore » of freedom that offer larger fields of view than possible with single-reflector designs. Dragone’s graphical design method does not lend itself readily to computer-based optical design approaches, but subsequent authors expanded on Dragone’s geometric design approach with analytic expressions that describe the location, shape, off-axis height and tilt of the telescope elements that satisfy Dragone’s design rules and can be used as a first-order design for subsequent computer-based design and optimization. We investigate two design variants that obey the Dragone-Mizuguchi conditions that exhibit ultra-low polarization crosstalk and a large diffraction-limited field of view well suited to millimeter-wave imaging arrays.« less

Brain metabolite alterations in infants born preterm with intrauterine growth restriction: association with structural changes and neurodevelopmental outcome.

PubMed

Simões, Rui V; Muñoz-Moreno, Emma; Cruz-Lemini, Mónica; Eixarch, Elisenda; Bargalló, Núria; Sanz-Cortés, Magdalena; Gratacós, Eduard

2017-01-01

Intrauterine growth restriction and premature birth represent 2 independent problems that may occur simultaneously and contribute to impaired neurodevelopment. The objective of the study was to assess changes in the frontal lobe metabolic profiles of 1 year old intrauterine growth restriction infants born prematurely and adequate-for-gestational-age controls, both premature and term adequate for gestational age and their association with brain structural and biophysical parameters and neurodevelopmental outcome at 2 years. A total of 26 prematurely born intrauterine growth restriction infants (birthweight <10th centile for gestational age), 22 prematurely born but adequate for gestational age controls, and 26 term adequate-for-gestational-age infants underwent brain magnetic resonance imaging and magnetic resonance spectroscopy at 1 year of age during natural sleep, on a 3 Tesla scanner. All brain T1-weighted and diffusion-weighted images were acquired along with short echo time single-voxel proton spectra from the frontal lobe. Magnetic resonance imaging/magnetic resonance spectroscopy data were processed to derive structural, biophysical, and metabolic information, respectively. Neurodevelopment was evaluated at 2 years of age using the Bayley Scales 3rd edition, assessing cognitive, language, motor, socioemotional, and adaptive behavior. Prematurely born intrauterine growth restriction infants had slightly smaller brain volumes and increased frontal lobe white matter mean diffusivity compared with both prematurely born but adequate for gestational age and term adequate for gestational age controls. Frontal lobe N-acetylaspartate levels were significantly lower in prematurely born intrauterine growth restriction than in prematurely born but adequate for gestational age infants but increased in prematurely born but adequate for gestational age compared with term adequate-for-gestational-age infants. The prematurely born intrauterine growth restriction group also showed slightly lower choline compounds, borderline decrements of estimated glutathione levels, and increased myoinositol to choline ratios, compared with prematurely born but adequate for gestational age controls. These specific metabolite changes were locally correlated to lower gray matter content and increased mean diffusivity and reduced white matter fraction and fractional anisotropy. Prematurely born intrauterine growth restriction infants also showed a tendency for poorer neurodevelopmental outcome at 2 years, associated with lower levels of frontal lobe N-acetylaspartate at 1 year within the preterm subset. Preterm intrauterine growth restriction infants showed altered brain metabolite profiles during a critical stage of brain maturation, which correlate with brain structural and biophysical parameters and neurodevelopmental outcome. Our results suggest altered neurodevelopmental trajectories in preterm intrauterine growth restriction and adequate-for-gestational-age infants, compared with term adequate-for-gestational-age infants, which require further characterization. Copyright © 2016 Elsevier Inc. All rights reserved.

Primary Care Practices' Abilities And Challenges In Using Electronic Health Record Data For Quality Improvement.

PubMed

Cohen, Deborah J; Dorr, David A; Knierim, Kyle; DuBard, C Annette; Hemler, Jennifer R; Hall, Jennifer D; Marino, Miguel; Solberg, Leif I; McConnell, K John; Nichols, Len M; Nease, Donald E; Edwards, Samuel T; Wu, Winfred Y; Pham-Singer, Hang; Kho, Abel N; Phillips, Robert L; Rasmussen, Luke V; Duffy, F Daniel; Balasubramanian, Bijal A

2018-04-01

Federal value-based payment programs require primary care practices to conduct quality improvement activities, informed by the electronic reports on clinical quality measures that their electronic health records (EHRs) generate. To determine whether EHRs produce reports adequate to the task, we examined survey responses from 1,492 practices across twelve states, supplemented with qualitative data. Meaningful-use participation, which requires the use of a federally certified EHR, was associated with the ability to generate reports-but the reports did not necessarily support quality improvement initiatives. Practices reported numerous challenges in generating adequate reports, such as difficulty manipulating and aligning measurement time frames with quality improvement needs, lack of functionality for generating reports on electronic clinical quality measures at different levels, discordance between clinical guidelines and measures available in reports, questionable data quality, and vendors that were unreceptive to changing EHR configuration beyond federal requirements. The current state of EHR measurement functionality may be insufficient to support federal initiatives that tie payment to clinical quality measures.

Primary Care Practices’ Abilities And Challenges In Using Electronic Health Record Data For Quality Improvement

PubMed Central

Cohen, Deborah J.; Dorr, David A.; Knierim, Kyle; DuBard, C. Annette; Hemler, Jennifer R.; Hall, Jennifer D.; Marino, Miguel; Solberg, Leif I.; McConnell, K. John; Nichols, Len M.; Nease, Donald E.; Edwards, Samuel T.; Wu, Winfred Y.; Pham-Singer, Hang; Kho, Abel N.; Phillips, Robert L.; Rasmussen, Luke V.; Duffy, F. Daniel; Balasubramanian, Bijal A.

2018-01-01

Federal value-based payment programs require primary care practices to conduct quality improvement activities, informed by the electronic reports on clinical quality measures that their electronic health records (EHRs) generate. To determine whether EHRs produce reports adequate to the task, we examined survey responses from 1,492 practices across twelve states, supplemented with qualitative data. Meaningful-use participation, which requires the use of a federally certified EHR, was associated with the ability to generate reports—but the reports did not necessarily support quality improvement initiatives. Practices reported numerous challenges in generating adequate reports, such as difficulty manipulating and aligning measurement time frames with quality improvement needs, lack of functionality for generating reports on electronic clinical quality measures at different levels, discordance between clinical guidelines and measures available in reports, questionable data quality, and vendors that were unreceptive to changing EHR configuration beyond federal requirements. The current state of EHR measurement functionality may be insufficient to support federal initiatives that tie payment to clinical quality measures. PMID:29608365

Significant components of service brand equity in healthcare sector.

PubMed

Chahal, Hardeep; Bala, Madhu

2012-01-01

The purpose of the study is to examine three significant components of service brand equity--i.e. perceived service quality, brand loyalty, and brand image--and analyze relationships among the components of brand equity and also their relationship with brand equity, which is still to be theorized and developed in the healthcare literature. Effective responses were received from 206 respondents, selected conveniently from the localities of Jammu city. After scale item analysis, the data were analyzed using factor analysis, correlations, t-tests, multiple regression analysis and path modeling using SEM. The findings of the study support that service brand equity in the healthcare sector is greatly influenced by brand loyalty and perceived quality. However, brand image has an indirect effect on service brand equity through brand loyalty (mediating variable). The research can be criticized on the ground that data were selected conveniently from respondents residing in the city of Jammu, India. But at the same time the respondents were appropriate for the study as they have adequate knowledge about the hospitals, and were associated with the selected hospital for more than four years. Furthermore, the validity and reliability of the data are strong enough to take care of the limitations of the convenience sampling selection method. The study has unique value addition to the service marketing vis-à-vis healthcare literature, from both theoretical and managerial perspectives. The study establishes a direct and significant relationship between service brand equity and its two components, i.e. perceived service quality and brand loyalty in the healthcare sector. It also provides directions to healthcare service providers in creating, enhancing, and maintaining service brand equity through service quality and brand loyalty, to sustain competitive advantage.

Is screening with digital imaging using one retinal view adequate?

PubMed

Herbert, H M; Jordan, K; Flanagan, D W

2003-05-01

To compare the detection of diabetic retinopathy from digital images with slit-lamp biomicroscopy, and to determine whether British Diabetic Association (BDA) screening criteria are attained (>80% sensitivity, >95% specificity, &<5% technical failure). Diabetics referred for screening were studied in a prospective fashion. A single 45 degrees fundus image was obtained using the nonmydriatic digital camera. Each patient subsequently underwent slit-lamp biomicroscopy and diabetic retinopathy grading by a consultant ophthalmologist. Diabetic retinopathy and maculopathy was graded according to the Early Treatment of Diabetic Retinopathy Study. A total of 145 patients (288 eyes) were identified for screening. Of these, 26% of eyes had diabetic retinopathy, and eight eyes (3%) had sight-threatening diabetic retinopathy requiring treatment. The sensitivity for detection of any diabetic retinopathy was 38% and the specificity 95%. There was a 4% technical failure rate. There were 42/288 false negatives and 10/288 false positives. Of the 42 false negatives, 18 represented diabetic maculopathy, 20 represented peripheral diabetic retinopathy and four eyes had both macular and peripheral changes. Three eyes in the false-negative group (1% of total eyes) had sight-threatening retinopathy. There was good concordance between the two consultants (79% agreement on slit-lamp biomicroscopy and 84% on digital image interpretation). The specificity value and technical failure rate compare favourably with BDA guidelines. The low sensitivity for detection of any retinopathy reflects failure to detect minimal maculopathy and retinopathy outside the 45 degrees image. This could be improved by an additional nasal image and careful evaluation of macular images with a low threshold for slit-lamp biomicroscopy if image quality is poor.

Mobile-Based Analysis of Malaria-Infected Thin Blood Smears: Automated Species and Life Cycle Stage Determination.

PubMed

Rosado, Luís; da Costa, José M Correia; Elias, Dirk; Cardoso, Jaime S

2017-09-21

Microscopy examination has been the pillar of malaria diagnosis, being the recommended procedure when its quality can be maintained. However, the need for trained personnel and adequate equipment limits its availability and accessibility in malaria-endemic areas. Rapid, accurate, accessible diagnostic tools are increasingly required, as malaria control programs extend parasite-based diagnosis and the prevalence decreases. This paper presents an image processing and analysis methodology using supervised classification to assess the presence of malaria parasites and determine the species and life cycle stage in Giemsa-stained thin blood smears. The main differentiation factor is the usage of microscopic images exclusively acquired with low cost and accessible tools such as smartphones, a dataset of 566 images manually annotated by an experienced parasilogist being used. Eight different species-stage combinations were considered in this work, with an automatic detection performance ranging from 73.9% to 96.2% in terms of sensitivity and from 92.6% to 99.3% in terms of specificity. These promising results attest to the potential of using this approach as a valid alternative to conventional microscopy examination, with comparable detection performances and acceptable computational times.

Color management in textile application

NASA Astrophysics Data System (ADS)

De Lucia, Maurizio; Vannucci, Massimiliano; Buonopane, Massimo; Fabroni, Cosimo; Fabrini, Francesco

2002-03-01

The aim of this research was to study a system of acquisition and processing of images capable of confronting colored wool with a reference specimen, in order to define the conformity using objective parameters. The first step of the research was to comprise and to analyze in depth the problem: there has been numerous implications of technical, physical, cultural, biological and also psychological character, that come down from the attempt of giving a quantitative appraisal to the color. In the scene of the national and international scientific and technological research, little has been made as regards measurement of color through digital processing of the images through linear CCD. The reason is fundamentally of technological nature: only during the last years we found the presence on the market of low cost equipment capable of acquiring and processing images with adequate performances and qualities. The job described has permitted to create a first prototype of system for the color measuring with use of CCD linear devices. -Hardware identification to carry out a series of tests and experiments in laboratory. -Verification of such device in a textile facility. -Statistics analysis of the collected data and of the employed models.

Mobile-Based Analysis of Malaria-Infected Thin Blood Smears: Automated Species and Life Cycle Stage Determination

PubMed Central

da Costa, José M. Correia; Elias, Dirk

2017-01-01

Microscopy examination has been the pillar of malaria diagnosis, being the recommended procedure when its quality can be maintained. However, the need for trained personnel and adequate equipment limits its availability and accessibility in malaria-endemic areas. Rapid, accurate, accessible diagnostic tools are increasingly required, as malaria control programs extend parasite-based diagnosis and the prevalence decreases. This paper presents an image processing and analysis methodology using supervised classification to assess the presence of malaria parasites and determine the species and life cycle stage in Giemsa-stained thin blood smears. The main differentiation factor is the usage of microscopic images exclusively acquired with low cost and accessible tools such as smartphones, a dataset of 566 images manually annotated by an experienced parasilogist being used. Eight different species-stage combinations were considered in this work, with an automatic detection performance ranging from 73.9% to 96.2% in terms of sensitivity and from 92.6% to 99.3% in terms of specificity. These promising results attest to the potential of using this approach as a valid alternative to conventional microscopy examination, with comparable detection performances and acceptable computational times. PMID:28934170

Developing a Low-Cost System for 3d Data Acquisition

NASA Astrophysics Data System (ADS)

Kossieris, S.; Kourounioti, O.; Agrafiotis, P.; Georgopoulos, A.

2017-11-01

In this paper, a developed low-cost system is described, which aims to facilitate 3D documentation fast and reliably by acquiring the necessary data in outdoor environment for the 3D documentation of façades especially in the case of very narrow streets. In particular, it provides a viable solution for buildings up to 8-10m high and streets as narrow as 2m or even less. In cases like that, it is practically impossible or highly time-consuming to acquire images in a conventional way. This practice would lead to a huge number of images and long processing times. The developed system was tested in the narrow streets of a medieval village on the Greek island of Chios. There, in order to by-pass the problem of short taking distances, it was thought to use high definition action cameras together with a 360˚ camera, which are usually provided with very wide-angle lenses and are capable of acquiring images, of high definition, are rather cheap and, most importantly, extremely light. Results suggest that the system can perform fast 3D data acquisition adequate for deliverables of high quality.

The brilliant beauty of the eye: light reflex from the cornea and tear film.

PubMed

Goto, Eiki

2006-12-01

Light reflex from the cornea and tear film as contributors to beautiful eyes ("eye sparkling") are reviewed. A systematic literature review was conducted using "Purkinje-Sanson image," "corneal light reflex," "corneal topography," "corneal wavefront aberration," and "tear interference image" as search terms. Articles on corneal surface regularity and stability and tear interferometry of the precorneal tear lipid layer were reviewed. PS-1 image, that is light reflex from the cornea and tear film, is widely used in practical ophthalmic examination. To achieve a brilliant beauty of the eye ("eye sparkling"), it is important that the tear film (aqueous layer) surface is smooth and stable with adequate tear volume and that the tear lipid layer is present in adequate thickness.

7 CFR 634.5 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... portion of the 208 water-quality management plan. (s) OMB Circular A-34. “Instructions on Budget Execution... needed to attain water quality standards or water quality goals. Fifty (50) percent of the adequate level... agency. A soil conservation district, State soil and water conservation agency, or State water quality...

7 CFR 634.5 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... portion of the 208 water-quality management plan. (s) OMB Circular A-34. “Instructions on Budget Execution... needed to attain water quality standards or water quality goals. Fifty (50) percent of the adequate level... agency. A soil conservation district, State soil and water conservation agency, or State water quality...

Comparison between whole-body and head and neck neurovascular coils for 3-T magnetic resonance proton resonance frequency shift thermography guidance in the head and neck region.

PubMed

Ginat, Daniel Thomas; Anthony, Gregory J; Christoforidis, Gregory; Oto, Aytekin; Dalag, Leonard; Sammet, Steffen

2018-02-01

The purpose of this study is to compare the image quality of magnetic resonance (MR) treatment planning images and proton resonance frequency (PRF) shift thermography images and inform coil selection for MR-guided laser ablation of tumors in the head and neck region. Laser ablation was performed on an agar phantom and monitored via MR PRF shift thermography on a 3-T scanner, following acquisition of T1-weighted (T1W) planning images. PRF shift thermography images and T2-weighted (T2W) planning images were also performed in the neck region of five normal human volunteers. Signal-to-noise ratios (SNR) and temperature uncertainty were calculated and compared between scans acquired with the quadrature mode body integrated coil and a head and neck neurovascular coil. T1W planning images of the agar phantom produced SNRs of 4.0 and 12.2 for the quadrature mode body integrated coil and head and neck neurovascular coil, respectively. The SNR of the phantom MR thermography magnitude images obtained using the quadrature mode body integrated coil was 14.4 versus 59.6 using the head and neck coil. The average temperature uncertainty for MR thermography performed on the phantom with the quadrature mode body integrated coil was 1.1 versus 0.3 °C with the head and neck coil. T2W planning images of the neck in five human volunteers produced SNRs of 28.3 and 91.0 for the quadrature mode body integrated coil and head and neck coil, respectively. MR thermography magnitude images of the neck in the volunteers obtained using the quadrature mode body integrated coil had a signal-to-noise ratio of 8.3, while the SNR using the head and neck coil was 16.1. The average temperature uncertainty for MR thermography performed on the volunteers with the body coil was 2.5 versus 1.6 °C with the head and neck neurovascular coil. The quadrature mode body integrated coil provides inferior image quality for both basic treatment planning sequences and MR PRF shift thermography compared with a neurovascular coil, but may nevertheless be adequate for clinical purposes.

Development of Whole Slide Imaging on Smartphones and Evaluation With ThinPrep Cytology Test Samples: Follow-Up Study.

PubMed

Huang, Yu-Ning; Peng, Xing-Chun; Ma, Shuoxin; Yu, Hong; Jin, Yu-Biao; Zheng, Jun; Fu, Guo-Hui

2018-04-04

The smartphone-based whole slide imaging (WSI) system represents a low-cost and effective alternative to automatic scanners for telepathology. In a previous study, the development of one such solution, named scalable whole slide imaging (sWSI), was presented and analyzed. A clinical evaluation of its iOS version with 100 frozen section samples verified the diagnosis-readiness of the produced virtual slides. The first aim of this study was to delve into the quantifying issues encountered in the development of an Android version. It should also provide insights into future high-resolution real-time feedback medical imaging apps on Android and invoke the awareness of smartphone manufacturers for collaboration. The second aim of this study was to further verify the clinical value of sWSI with cytology samples. This type is different from the frozen section samples in that they require finer detail on the cellular level. During sWSI development on Android, it was discovered that many models do not support uncompressed camera pixel data with sufficient resolution and full field of view. The proportion of models supporting the optimal format was estimated in a test on 200 mainstream Android models. Other factors, including slower processing speed and camera preview freezing, also led to inferior performance of sWSI on Android compared with the iOS version. The processing speed was mostly determined by the central processing unit frequency in theory, and the relationship was investigated in the 200-model simulation experiment with physical devices. The camera preview freezing was caused by the lag between triggering photo capture and resuming preview. In the clinical evaluation, 100 ThinPrep cytology test samples covering 6 diseases were scanned with sWSI and compared against the ground truth of optical microscopy. Among the tested Android models, only 3.0% (6/200) provided an optimal data format, meeting all criteria of quality and efficiency. The image-processing speed demonstrated a positive relationship with the central processing unit frequency but to a smaller degree than expected and was highly model-dependent. The virtual slides produced by sWSI on Android and iOS of ThinPrep cytology test samples achieved similar high quality. Using optical microscopy as the ground truth, pathologists made a correct diagnosis on 87.5% (175/200) of the cases with sWSI virtual slides. Depending on the sWSI version and the pathologist in charge, the kappa value varied between .70 and .82. All participating pathologists considered the quality of the sWSI virtual slides in the experiment to be adequate for routine usage. Limited by hardware and operating system support, the performance of sWSI on mainstream Android smartphones did not fully match the iOS version. However, in practice, this difference was not significant, and both were adequate for digitizing most of the sample types for telepathology consultation. ©Yu-Ning Huang, Xing-Chun Peng, Shuoxin Ma, Hong Yu, Yu-Biao Jin, Jun Zheng, Guo-Hui Fu. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 04.04.2018.

Imaging in the Age of Precision Medicine: Summary of the Proceedings of the 10th Biannual Symposium of the International Society for Strategic Studies in Radiology.

PubMed

Herold, Christian J; Lewin, Jonathan S; Wibmer, Andreas G; Thrall, James H; Krestin, Gabriel P; Dixon, Adrian K; Schoenberg, Stefan O; Geckle, Rena J; Muellner, Ada; Hricak, Hedvig

2016-04-01

During the past decade, with its breakthroughs in systems biology, precision medicine (PM) has emerged as a novel health-care paradigm. Challenging reductionism and broad-based approaches in medicine, PM is an approach for disease treatment and prevention that takes into account individual variability in genes, environment, and lifestyle. It involves integrating information from multiple sources in a holistic manner to achieve a definitive diagnosis, focused treatment, and adequate response assessment. Biomedical imaging and imaging-guided interventions, which provide multiparametric morphologic and functional information and enable focused, minimally invasive treatments, are key elements in the infrastructure needed for PM. The emerging discipline of radiogenomics, which links genotypic information to phenotypic disease manifestations at imaging, should also greatly contribute to patient-tailored care. Because of the growing volume and complexity of imaging data, decision-support algorithms will be required to help physicians apply the most essential patient data for optimal management. These innovations will challenge traditional concepts of health care and business models. Reimbursement policies and quality assurance measures will have to be reconsidered and adapted. In their 10th biannual symposium, which was held in August 2013, the members of the International Society for Strategic Studies in Radiology discussed the opportunities and challenges arising for the imaging community with the transition to PM. This article summarizes the discussions and central messages of the symposium.

Bowel MR imaging with oral Gastrografin: an experimental study with healthy volunteers.

PubMed

Borthne, A S; Dormagen, J B; Gjesdal, K I; Storaas, T; Lygren, I; Geitung, J T

2003-01-01

Our objective was to evaluate Gastrografin for MR bowel imaging. Twenty-three healthy volunteers in two randomised groups received 300 or 400 ml 50% Gastrografin, drunk continuously during 2 and 3 h, respectively. Images were applied during breath-hold in three orthogonal orientations. The balanced fast-field echo (BFFE) and balanced turbo field-echo (BTFE) sequences, with acquisition times from 13 to 25 s, were used before gadolinium (Gd) DTPA implying 1- to 2-mm-thick slices locally or 6-mm-thick slices through the entire gastrointestinal tract. The Gd-enhanced images were performed using a 3D T1-weighted FFE sequence with water selective excitation (Proset). Image quality, including bowel distention, homogeneity of opacification and wall conspicuity, were evaluated by two experienced reviewers, and the adverse reactions were recorded. Very good or excellent distention, homogeneity and wall conspicuity were achieved in the central segments from the ileum to the left colon flexure in 83-96% of cases, due to the adequate contrast media supply in these regions. Distention, homogeneity and delineation were good in the central segments of the remaining bowels. Diarrhoea was a major problem affecting all participants, followed by nausea. Provided that there is modern fast sequential technology, excellent MR imaging of the bowel can be achieved by the oral administration 50% diluted Gastrografin. Further studies are needed to refine the technique and optimise the quantity and concentration of Gastrografin in order to avoid or reduce adverse reactions.

[Stress-ECG is adequate to detect myocardial ischemia: when are additional diagnostic tests needed?].

PubMed

Baer, F M

2007-09-01

The stress-ECG is the most often adopted and most cost effective initial diagnostic test for the assessment of myocardial ischemia in patients with suspected coronary artery disease (CAD). Prerequisites for the diagnostic usefullness of stress-ECG are a clearly interpretable ST-segment, ability to reach the predicted work load, an intermediate pretest probability for CAD ranging between 10% and 90% and the absence of any contraindications for dynamic exercise. Because of the limited diagnostic sensitivity of about 70%, and a high percentage of patients, who are unable to exercise, a negative stress ECG can definitely not exclude hemodynamically significant CAD. Therefore, stress imaging techniques like myocardial scintigraphy, stress-echocardiography and stress magnetic resonance imaging play a major role in the stepwise diagnostic work-up of patients with suspected CAD. These stress imaging techniques are basically interchangeable since no method is definitely superior to one of the others. However, each method has its specific pros and cons and inherent contraindications. Therefore the choice of the stress imaging method and the form of stress applied should be based on the individual patients characteristics to gain optimal image quality and diagnostic accuracy. Moreover, the decision for one method should take the local availability and institutional expertise of diagnostic centers into account. Although partly substituted by stress imaging techniques the stress-ECG still remains the workhorse for a stepwise diagnostic work-up of patients with suspected CAD.

Impact of the quality of coronal restoration and root canal filling on the periapical health in adult syrian subpopulation

PubMed Central

Alafif, Hisham

2014-01-01

Background: The purpose of this study was to determine the status of periapical tissues of endodontically treated teeth according to coronal restorations and root canal fillings separately and in concomitant in adult Syrian subpopulation. Methods: 784 endodontically treated teeth from two hundred randomly selected Syrian adult patients were radiographically evaluated. According to predetermined criteria, the quality of coronal restorations and root canal filling of each tooth was scored as adequate or inadequate. The status of periapical tissues was also classified as healthy or diseased. Results were analyzed using Chi-squared test. Results: Adequate coronal restorations were determined in 58.54% of cases which was accompanied with less periapical pathosis than that in teeth with inadequate restorations (P < 0.01). 14% of teeth were restored by posts which showed no significant impact on the periapical tissues health. 18.5% of endodontic treatments were evaluated as adequate with less number of periapical radiolucencies than that of inadequate root canal fillings (P < 0.01). Absence of periapical pathosis was 96.6% in cases with both adequate coronal restorations and root canals fillings. The rate was 88.5% in cases with only adequate root canals fillings, and about 70% in cases with only adequate coronal restorations. When the treatment was inadequate in both coronal and root canals fillings, success rate was only observed in 48.8%. Conclusion: The most important factor with regard to the periradicular tissue health is the quality of root canal filling without neglecting the influence of coronal restoration (regardless of its type). There is a high prevalence rate of periapical pathosis in Syrian subpopulation due to poor dental practice. PMID:25565729

Agreement studies in radiology research.

PubMed

Farzin, B; Gentric, J-C; Pham, M; Tremblay-Paquet, S; Brosseau, L; Roy, C; Jamali, S; Chagnon, M; Darsaut, T E; Guilbert, F; Naggara, O; Raymond, J

2017-03-01

The goal of this study was to estimate the frequency and the quality of agreement studies published in diagnostic imaging journals. All studies published between January 2011 and December 2012 in four radiology journals were reviewed. Four trained readers evaluated agreement studies using a 24-item form that included the 15 items of the Guidelines for Reporting Reliability and Agreement Studies criteria. Of 2229 source titles, 280 studies (13%) reported agreement. The mean number of patients per study was 81±99 (SD) (range, 0-180). Justification for sample size was found in 9 studies (3%). The number of raters was≤2 in 226 studies (81%). No intra-observer study was performed in 212 (76%) articles. Confidence intervals and interpretation of statistical estimates were provided in 98 (35%) and 147 (53%) of the studies, respectively. In 168 studies (60%), the agreement study was not mentioned in the discussion section. In 8 studies (3%), reporting of the agreement study was judged to be adequate. Twenty studies (7%) were dedicated to agreement. Agreement studies are preliminary and not adequately reported. Studies dedicated to agreement are infrequent. They are research opportunities that should be promoted. Copyright © 2016 Éditions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

Associations between diet quality, health status and diabetic complications in patients with type 2 diabetes and comorbid obesity.

PubMed

Mangou, Apostolis; Grammatikopoulou, Maria G; Mirkopoulou, Daphne; Sailer, Nikolaos; Kotzamanidis, Charalambos; Tsigga, Maria

2012-02-01

Patients with type 2 diabetes (T2DM) demonstrate low dietary adherence and this is further aggravated with comorbid obesity. The aim of the present study was to assess diet quality in patients with T2DM and comorbid obesity compared to patients with T2DM alone and to examine the associations between comorbidities and diet quality. The sample consisted of 59 adult patients with diabesity (T2DM and comorbid obesity) and 94 patients with T2DM alone. All diabetes comorbidities and complications were recorded and diet quality was assessed with the Healthy Eating Index (HEI). Mean raw HEI of the diabese subjects was 81.9±7.1 and the diabetic subjects was 80.2±6.9. When HEI was adjusted to the sex, age and weight status, the diabese demonstrated a higher HEI. Among comorbidities, only renal disease decreased HEI. According to the principal component analysis of the total sample, adequate diet quality was explained by cardiovascular disease, cigarette smoking, alcohol consumption, peptic ulcer, sex, diabesity and diabetic foot syndrome. In the diabese, adequate HEI was explained by diabetic foot syndrome, smoking, drinking alcohol and having a family history of diabetes. Adult patients with T2DM demonstrate adequate diet quality. Different factors are associated with the adoption of a high quality diet between the diabese and the T2DM alone. Copyright © 2011 SEEN. Published by Elsevier Espana. All rights reserved.

Image quality and dose differences caused by vendor-specific image processing of neonatal radiographs.

PubMed

Sensakovic, William F; O'Dell, M Cody; Letter, Haley; Kohler, Nathan; Rop, Baiywo; Cook, Jane; Logsdon, Gregory; Varich, Laura

2016-10-01

Image processing plays an important role in optimizing image quality and radiation dose in projection radiography. Unfortunately commercial algorithms are black boxes that are often left at or near vendor default settings rather than being optimized. We hypothesize that different commercial image-processing systems, when left at or near default settings, create significant differences in image quality. We further hypothesize that image-quality differences can be exploited to produce images of equivalent quality but lower radiation dose. We used a portable radiography system to acquire images on a neonatal chest phantom and recorded the entrance surface air kerma (ESAK). We applied two image-processing systems (Optima XR220amx, by GE Healthcare, Waukesha, WI; and MUSICA(2) by Agfa HealthCare, Mortsel, Belgium) to the images. Seven observers (attending pediatric radiologists and radiology residents) independently assessed image quality using two methods: rating and matching. Image-quality ratings were independently assessed by each observer on a 10-point scale. Matching consisted of each observer matching GE-processed images and Agfa-processed images with equivalent image quality. A total of 210 rating tasks and 42 matching tasks were performed and effective dose was estimated. Median Agfa-processed image-quality ratings were higher than GE-processed ratings. Non-diagnostic ratings were seen over a wider range of doses for GE-processed images than for Agfa-processed images. During matching tasks, observers matched image quality between GE-processed images and Agfa-processed images acquired at a lower effective dose (11 ± 9 μSv; P < 0.0001). Image-processing methods significantly impact perceived image quality. These image-quality differences can be exploited to alter protocols and produce images of equivalent image quality but lower doses. Those purchasing projection radiography systems or third-party image-processing software should be aware that image processing can significantly impact image quality when settings are left near default values.

40 CFR 230.30 - Threatened and endangered species.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., fish and reptiles. (b) Possible loss of values: The major potential impacts on threatened or endangered... species include adequate good quality water, spawning and maturation areas, nesting areas, protective cover, adequate and reliable food supply, and resting areas for migratory species. Each of these...

30 CFR 74.6 - Quality control.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Quality control. 74.6 Section 74.6 Mineral... of the CMDPSU will be maintained in production through adequate quality control procedures, MSHA and... DUST SAMPLING DEVICES Approval Requirements for Coal Mine Dust Personal Sampler Unit § 74.6 Quality...

Genetic variation for agronomic and fiber quality traits in a population derived from high-quality cotton germplasm

USDA-ARS?s Scientific Manuscript database

Genetic improvement of fiber quality is necessary to meet the requirements of processors and users of cotton fiber. To foster genetic improvement of cotton fiber quality, adequate genetic variation for the quantitatively inherited physical properties of cotton is required. Additionally, knowledge of...

Educational Auditing and Quality Assurance. Occasional Paper No. 4.

ERIC Educational Resources Information Center

Conner, James E.; Lessinger, Leon M.

This paper considers how to respond to new requirements for adequate disclosure of the schools' performance to the public. It proposes the use of three powerful constructs--quality control, quality assurance, and an independent educational accomplishment audit (IEAA). The essential elements of quality control are agreeing on and specifying desired…

Comparison of existing digital image analysis systems for the analysis of Thematic Mapper data

NASA Technical Reports Server (NTRS)

Likens, W. C.; Wrigley, R. C.

1984-01-01

Most existing image analysis systems were designed with the Landsat Multi-Spectral Scanner in mind, leaving open the question of whether or not these systems could adequately process Thematic Mapper data. In this report, both hardware and software systems have been evaluated for compatibility with TM data. Lack of spectral analysis capability was not found to be a problem, though techniques for spatial filtering and texture varied. Computer processing speed and data storage of currently existing mini-computer based systems may be less than adequate. Upgrading to more powerful hardware may be required for many TM applications.

Low-dose head computed tomography in children: a single institutional experience in pediatric radiation risk reduction: clinical article.

PubMed

Morton, Ryan P; Reynolds, Renee M; Ramakrishna, Rohan; Levitt, Michael R; Hopper, Richard A; Lee, Amy; Browd, Samuel R

2013-10-01

In this study, the authors describe their experience with a low-dose head CT protocol for a preselected neurosurgical population at a dedicated pediatric hospital (Seattle Children's Hospital), the largest number of patients with this protocol reported to date. All low-dose head CT scans between October 2011 and November 2012 were reviewed. Two different low-dose radiation dosages were used, at one-half or one-quarter the dose of a standard head CT scan, based on patient characteristics agreed upon by the neurosurgery and radiology departments. Patient information was also recorded, including diagnosis and indication for CT scan. Six hundred twenty-four low-dose head CT procedures were performed within the 12-month study period. Although indications for the CT scans varied, the most common reason was to evaluate the ventricles and catheter placement in hydrocephalic patients with shunts (70%), followed by postoperative craniosynostosis imaging (12%). These scans provided adequate diagnostic imaging, and no patient required a follow-up full-dose CT scan as a result of poor image quality on a low-dose CT scan. Overall physician comfort and satisfaction with interpretation of the images was high. An additional 2150 full-dose head CT scans were performed during the same 12-month time period, making the total number of CT scans 2774. This value compares to 3730 full-dose head CT scans obtained during the year prior to the study when low-dose CT and rapid-sequence MRI was not a reliable option at Seattle Children's Hospital. Thus, over a 1-year period, 22% of the total CT scans were able to be converted to low-dose scans, and full-dose CT scans were able to be reduced by 42%. The implementation of a low-dose head CT protocol substantially reduced the amount of ionizing radiation exposure in a preselected population of pediatric neurosurgical patients. Image quality and diagnostic utility were not significantly compromised.

Methodological quality of diagnostic accuracy studies on non-invasive coronary CT angiography: influence of QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) items on sensitivity and specificity.

PubMed

Schueler, Sabine; Walther, Stefan; Schuetz, Georg M; Schlattmann, Peter; Dewey, Marc

2013-06-01

To evaluate the methodological quality of diagnostic accuracy studies on coronary computed tomography (CT) angiography using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) tool. Each QUADAS item was individually defined to adapt it to the special requirements of studies on coronary CT angiography. Two independent investigators analysed 118 studies using 12 QUADAS items. Meta-regression and pooled analyses were performed to identify possible effects of methodological quality items on estimates of diagnostic accuracy. The overall methodological quality of coronary CT studies was merely moderate. They fulfilled a median of 7.5 out of 12 items. Only 9 of the 118 studies fulfilled more than 75 % of possible QUADAS items. One QUADAS item ("Uninterpretable Results") showed a significant influence (P = 0.02) on estimates of diagnostic accuracy with "no fulfilment" increasing specificity from 86 to 90 %. Furthermore, pooled analysis revealed that each QUADAS item that is not fulfilled has the potential to change estimates of diagnostic accuracy. The methodological quality of studies investigating the diagnostic accuracy of non-invasive coronary CT is only moderate and was found to affect the sensitivity and specificity. An improvement is highly desirable because good methodology is crucial for adequately assessing imaging technologies. • Good methodological quality is a basic requirement in diagnostic accuracy studies. • Most coronary CT angiography studies have only been of moderate design quality. • Weak methodological quality will affect the sensitivity and specificity. • No improvement in methodological quality was observed over time. • Authors should consider the QUADAS checklist when undertaking accuracy studies.

Extreme Tele-Echocardiography: Methodology for Remote Guidance of In-flight Echocardiography Aboard the International Space Station

NASA Technical Reports Server (NTRS)

Martin, David; Borowski, Allan; Bungo, Michael W.; Dulchavsky, Scott; Gladding, Patrick; Greenberg, Neil; Hamilton, Doug; Levine, Benjamin D.; Norwoord, Kelly; Platts, Steven H.;

Treatment of painful diabetic peripheral neuropathy.

PubMed

Rosenberg, Casandra J; Watson, James C

2015-02-01

Painful diabetic peripheral neuropathy impairs quality of life and can be difficult to treat. To discuss current treatment recommendations for painful diabetic peripheral neuropathy. Literature review. Systematic review of the literature discussing treatment of painful diabetic peripheral neuropathy. Existing treatment guidelines were studied and compared. Painful diabetic peripheral neuropathy occurs in about one in six people with diabetes. This condition impairs quality of life and increases healthcare costs. Treatment recommendations exist, but individual patient therapy can require a trial-and-error approach. Many treatment options have adjuvant benefits or side effects which should be considered prior to initiating therapy. Often, a combination of treatment modalities with various mechanisms of action is required for adequate pain control. Adequate medication titration and a reasonable trial period should be allowed. The treatment of painful diabetic peripheral neuropathy can be challenging, but effective management can improve patient's quality of life. Painful diabetic peripheral neuropathy impairs quality of life and can be difficult to treat. Many treatment options have adjuvant benefits or side effects which should be considered prior to initiating therapy. Often, a combination of treatment modalities with various mechanisms of action is required for adequate pain control. © The International Society for Prosthetics and Orthotics 2014.

Evaluation of MRI-US Fusion Technology in Sports-Related Musculoskeletal Injuries.

PubMed

Wong-On, Manuel; Til-Pérez, Lluís; Balius, Ramón

2015-06-01

A combination of magnetic resonance imaging (MRI) with real-time high-resolution ultrasound (US) known as fusion imaging may improve visualization of musculoskeletal (MSK) sports medicine injuries. The aim of this study was to evaluate the applicability of MRI-US fusion technology in MSK sports medicine. This study was conducted by the medical services of the FC Barcelona. The participants included volunteers and referred athletes with symptomatic and asymptomatic MSK injuries. All cases underwent MRI which was loaded into the US system for manual registration on the live US image and fusion imaging examination. After every test, an evaluation form was completed in terms of advantages, disadvantages, and anatomic fusion landmarks. From November 2014 to March 2015, we evaluated 20 subjects who underwent fusion imaging, 5 non-injured volunteers and 15 injured athletes, 11 symptomatic and 4 asymptomatic, age range 16-50 years, mean 22. We describe some of the anatomic landmarks used to guide fusion in different regions. This technology allowed us to examine muscle and tendon injuries simultaneously in US and MRI, and the correlation of both techniques, especially low-grade muscular injuries. This has also helped compensate for the limited field of view with US. It improves spatial orientation of cartilage, labrum and meniscal injuries. However, a high-quality MRI image is essential in achieving an adequate fusion image, and 3D sequences need to be added in MRI protocols to improve navigation. The combination of real-time MRI and US image fusion and navigation is relatively easy to perform and is helping to improve understanding of MSK injuries. However, it requires specific skills in MSK imaging and still needs further research in sports-related injuries. Toshiba Medical Systems Corporation.

Magnetic resonance imaging in experimental stroke and comparison with histology: systematic review and meta-analysis.

PubMed

Milidonis, Xenios; Marshall, Ian; Macleod, Malcolm R; Sena, Emily S

2015-03-01

Because the new era of preclinical stroke research demands improvements in validity and generalizability of findings, moving from single site to multicenter studies could be pivotal. However, the conduct of magnetic resonance imaging (MRI) in stroke remains ill-defined. We sought to assess the variability in the use of MRI for evaluating lesions post stroke and to examine the possibility as an alternative to gold standard histology for measuring the infarct size. We identified animal studies of ischemic stroke reporting lesion sizes using MRI. We assessed the degree of heterogeneity and reporting of scanning protocols, postprocessing methods, study design characteristics, and study quality. Studies performing histological evaluation of infarct size were further selected to compare with corresponding MRI using meta-regression. Fifty-four articles undertaking a total of 78 different MRI scanning protocols met the inclusion criteria. T2-weighted imaging was most frequently used (83% of the studies), followed by diffusion-weighted imaging (43%). Reporting of the imaging parameters was adequate, but heterogeneity between studies was high. Twelve studies assessed the infarct size using both MRI and histology at corresponding time points, with T2-weighted imaging-based treatment effect having a significant positive correlation with histology (; P<0.001). Guidelines for standardized use and reporting of MRI in preclinical stroke are urgently needed. T2-weighted imaging could be used as an effective in vivo alternative to histology for estimating treatment effects based on the extent of infarction; however, additional studies are needed to explore the effect of individual parameters. © 2015 American Heart Association, Inc.

Wavefront Sensing for WFIRST with a Linear Optical Model

NASA Technical Reports Server (NTRS)

Jurling, Alden S.; Content, David A.

2012-01-01

In this paper we develop methods to use a linear optical model to capture the field dependence of wavefront aberrations in a nonlinear optimization-based phase retrieval algorithm for image-based wavefront sensing. The linear optical model is generated from a ray trace model of the system and allows the system state to be described in terms of mechanical alignment parameters rather than wavefront coefficients. This approach allows joint optimization over images taken at different field points and does not require separate convergence of phase retrieval at individual field points. Because the algorithm exploits field diversity, multiple defocused images per field point are not required for robustness. Furthermore, because it is possible to simultaneously fit images of many stars over the field, it is not necessary to use a fixed defocus to achieve adequate signal-to-noise ratio despite having images with high dynamic range. This allows high performance wavefront sensing using in-focus science data. We applied this technique in a simulation model based on the Wide Field Infrared Survey Telescope (WFIRST) Intermediate Design Reference Mission (IDRM) imager using a linear optical model with 25 field points. We demonstrate sub-thousandth-wave wavefront sensing accuracy in the presence of noise and moderate undersampling for both monochromatic and polychromatic images using 25 high-SNR target stars. Using these high-quality wavefront sensing results, we are able to generate upsampled point-spread functions (PSFs) and use them to determine PSF ellipticity to high accuracy in order to reduce the systematic impact of aberrations on the accuracy of galactic ellipticity determination for weak-lensing science.

Evaluation of Quality of Lower Limb Arthroplasty Observational Studies Using the Assessment of Quality in Lower Limb Arthroplasty (AQUILA) Checklist.

PubMed

Cowan, James B; Mlynarek, Ryan A; Nelissen, Rob G H H; Pijls, Bart G C W; Gagnier, Joel J

2015-09-01

This study used the assessment of quality in lower limb arthroplasty (AQUILA) checklist to assess the quality of lower limb arthroplasty observational studies. Among 132 studies the mean reporting quality score was 5.4 (SD=1.2) out of 8 possible points. Most studies adequately reported reasons for revisions (98%) and prosthesis brand and fixation (95%) in sufficient detail. Only 3% of studies adequately reported the number of patients unwilling to participate, 15% stated a clear primary research question or hypothesis, 11% reported a worst-case analysis or competing risk analysis for endpoints, and 42% reported more than 5% of patients were lost to follow-up. There is significant room for improvement in the reporting and methodology of lower limb arthroplasty observational studies. Level III. Copyright © 2015 Elsevier Inc. All rights reserved.

DRACO-STEM: An Automatic Tool to Generate High-Quality 3D Meshes of Shoot Apical Meristem Tissue at Cell Resolution

PubMed Central

Cerutti, Guillaume; Ali, Olivier; Godin, Christophe

2017-01-01

Context: The shoot apical meristem (SAM), origin of all aerial organs of the plant, is a restricted niche of stem cells whose growth is regulated by a complex network of genetic, hormonal and mechanical interactions. Studying the development of this area at cell level using 3D microscopy time-lapse imaging is a newly emerging key to understand the processes controlling plant morphogenesis. Computational models have been proposed to simulate those mechanisms, however their validation on real-life data is an essential step that requires an adequate representation of the growing tissue to be carried out. Achievements: The tool we introduce is a two-stage computational pipeline that generates a complete 3D triangular mesh of the tissue volume based on a segmented tissue image stack. DRACO (Dual Reconstruction by Adjacency Complex Optimization) is designed to retrieve the underlying 3D topological structure of the tissue and compute its dual geometry, while STEM (SAM Tissue Enhanced Mesh) returns a faithful triangular mesh optimized along several quality criteria (intrinsic quality, tissue reconstruction, visual adequacy). Quantitative evaluation tools measuring the performance of the method along those different dimensions are also provided. The resulting meshes can be used as input and validation for biomechanical simulations. Availability: DRACO-STEM is supplied as a package of the open-source multi-platform plant modeling library OpenAlea (http://openalea.github.io/) implemented in Python, and is freely distributed on GitHub (https://github.com/VirtualPlants/draco-stem) along with guidelines for installation and use. PMID:28424704

Evaluation of H.264 and H.265 full motion video encoding for small UAS platforms

NASA Astrophysics Data System (ADS)

McGuinness, Christopher D.; Walker, David; Taylor, Clark; Hill, Kerry; Hoffman, Marc

2016-05-01

Of all the steps in the image acquisition and formation pipeline, compression is the only process that degrades image quality. A selected compression algorithm succeeds or fails to provide sufficient quality at the requested compression rate depending on how well the algorithm is suited to the input data. Applying an algorithm designed for one type of data to a different type often results in poor compression performance. This is mostly the case when comparing the performance of H.264, designed for standard definition data, to HEVC (High Efficiency Video Coding), which the Joint Collaborative Team on Video Coding (JCT-VC) designed for high-definition data. This study focuses on evaluating how HEVC compares to H.264 when compressing data from small UAS platforms. To compare the standards directly, we assess two open-source traditional software solutions: x264 and x265. These software-only comparisons allow us to establish a baseline of how much improvement can generally be expected of HEVC over H.264. Then, specific solutions leveraging different types of hardware are selected to understand the limitations of commercial-off-the-shelf (COTS) options. Algorithmically, regardless of the implementation, HEVC is found to provide similar quality video as H.264 at 40% lower data rates for video resolutions greater than 1280x720, roughly 1 Megapixel (MPx). For resolutions less than 1MPx, H.264 is an adequate solution though a small (roughly 20%) compression boost is earned by employing HEVC. New low cost, size, weight, and power (CSWAP) HEVC implementations are being developed and will be ideal for small UAS systems.

Forms in Search of Substance: Quality and Evaluation in Romanian Universities

ERIC Educational Resources Information Center

Geven, Koen; Maricut, Adina

2015-01-01

Romania's integration into the European Union is fraught with cultural stereotypes. One dominant narrative is that the country creates "forms without substance": meaningless institutions without adequate personnel or intellectual capital. In this paper, we investigate whether this popular stereotype adequately describes higher education…

10 CFR 32.210 - Registration of product information.

Code of Federal Regulations, 2012 CFR

2012-01-01

... device must include sufficient information about the design, manufacture, prototype testing, quality... source or device are adequate to protect health and minimize danger to life and property. (d) The NRC... source are adequate to protect health and minimize danger to life and property. (e) After completion of...

10 CFR 32.210 - Registration of product information.

Code of Federal Regulations, 2011 CFR

2011-01-01

... device must include sufficient information about the design, manufacture, prototype testing, quality... source or device are adequate to protect health and minimize danger to life and property. (d) The NRC... source are adequate to protect health and minimize danger to life and property. (e) After completion of...

Phantom feet on digital radionuclide images and other scary computer tales

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freitas, J.E.; Dworkin, H.J.; Dees, S.M.

1989-09-01

Malfunction of a computer-assisted digital gamma camera is reported. Despite what appeared to be adequate acceptance testing, an error in the system gave rise to switching of images and identification text. A suggestion is made for using a hot marker, which would avoid the potential error of misinterpretation of patient images.

Parallel Processing of Images in Mobile Devices using BOINC

NASA Astrophysics Data System (ADS)

Curiel, Mariela; Calle, David F.; Santamaría, Alfredo S.; Suarez, David F.; Flórez, Leonardo

2018-04-01

Medical image processing helps health professionals make decisions for the diagnosis and treatment of patients. Since some algorithms for processing images require substantial amounts of resources, one could take advantage of distributed or parallel computing. A mobile grid can be an adequate computing infrastructure for this problem. A mobile grid is a grid that includes mobile devices as resource providers. In a previous step of this research, we selected BOINC as the infrastructure to build our mobile grid. However, parallel processing of images in mobile devices poses at least two important challenges: the execution of standard libraries for processing images and obtaining adequate performance when compared to desktop computers grids. By the time we started our research, the use of BOINC in mobile devices also involved two issues: a) the execution of programs in mobile devices required to modify the code to insert calls to the BOINC API, and b) the division of the image among the mobile devices as well as its merging required additional code in some BOINC components. This article presents answers to these four challenges.

Heterogeneous sharpness for cross-spectral face recognition

NASA Astrophysics Data System (ADS)

Cao, Zhicheng; Schmid, Natalia A.

2017-05-01

Matching images acquired in different electromagnetic bands remains a challenging problem. An example of this type of comparison is matching active or passive infrared (IR) against a gallery of visible face images, known as cross-spectral face recognition. Among many unsolved issues is the one of quality disparity of the heterogeneous images. Images acquired in different spectral bands are of unequal image quality due to distinct imaging mechanism, standoff distances, or imaging environment, etc. To reduce the effect of quality disparity on the recognition performance, one can manipulate images to either improve the quality of poor-quality images or to degrade the high-quality images to the level of the quality of their heterogeneous counterparts. To estimate the level of discrepancy in quality of two heterogeneous images a quality metric such as image sharpness is needed. It provides a guidance in how much quality improvement or degradation is appropriate. In this work we consider sharpness as a relative measure of heterogeneous image quality. We propose a generalized definition of sharpness by first achieving image quality parity and then finding and building a relationship between the image quality of two heterogeneous images. Therefore, the new sharpness metric is named heterogeneous sharpness. Image quality parity is achieved by experimentally finding the optimal cross-spectral face recognition performance where quality of the heterogeneous images is varied using a Gaussian smoothing function with different standard deviation. This relationship is established using two models; one of them involves a regression model and the other involves a neural network. To train, test and validate the model, we use composite operators developed in our lab to extract features from heterogeneous face images and use the sharpness metric to evaluate the face image quality within each band. Images from three different spectral bands visible light, near infrared, and short-wave infrared are considered in this work. Both error of a regression model and validation error of a neural network are analyzed.

Feasibility and quality of nonmydriatic fundus photography in children

PubMed Central

Toffoli, Daniela; Bruce, Beau B.; Lamirel, Cédric; Henderson, Amanda D.; Newman, Nancy J.; Biousse, Valérie

2011-01-01

Purpose Ocular funduscopic examination is difficult in young children and is rarely attempted by nonophthalmologists. Our objective was to determine the feasibility of reliably obtaining high-quality nonmydriatic fundus photographs in children. Methods Nonmydriatic fundus photographs were obtained in both eyes of children seen in a pediatric ophthalmology clinic. Ease of fundus photography was recorded on a 10-point Likert scale (10 = very easy). Quality was graded from 1 to 5 (1, inadequate for any diagnostic purpose; 2, unable to exclude all emergent findings; 3, only able to exclude emergent findings; 4, not ideal, but still able to exclude subtle findings; and 5, ideal quality). The primary outcome measure was image quality by age. Results A total of 878 photographs of 212 children (median age, 6 years; range,1-18 years) were included. Photographs of at least one eye were obtained in 190 children (89.6%) and in both eyes in 181 (85.3%). Median rating for ease of photography was 7. Photographs of some clinical value (grade ≥2) were obtained in 33% of children <3 years and 95% >3 years. High-quality photographs (grade 4 or 5) were obtained in both eyes in 7% of children <3 years, 57% of children ≥3 to <7 years, 85% of children ≥7 to <9 years, and 65% of children ≥9 years. The youngest patient with high-quality photographs in both eyes was 22 months. Conclusions Nonmydriatic fundus photographs of adequate quality can be obtained in children over age 3 and in some children as young as 22 months. PMID:22153402

Using compressed images in multimedia education

NASA Astrophysics Data System (ADS)

Guy, William L.; Hefner, Lance V.

1996-04-01

The classic radiologic teaching file consists of hundreds, if not thousands, of films of various ages, housed in paper jackets with brief descriptions written on the jackets. The development of a good teaching file has been both time consuming and voluminous. Also, any radiograph to be copied was unavailable during the reproduction interval, inconveniencing other medical professionals needing to view the images at that time. These factors hinder motivation to copy films of interest. If a busy radiologist already has an adequate example of a radiological manifestation, it is unlikely that he or she will exert the effort to make a copy of another similar image even if a better example comes along. Digitized radiographs stored on CD-ROM offer marked improvement over the copied film teaching files. Our institution has several laser digitizers which are used to rapidly scan radiographs and produce high quality digital images which can then be converted into standard microcomputer (IBM, Mac, etc.) image format. These images can be stored on floppy disks, hard drives, rewritable optical disks, recordable CD-ROM disks, or removable cartridge media. Most hospital computer information systems include radiology reports in their database. We demonstrate that the reports for the images included in the users teaching file can be copied and stored on the same storage media as the images. The radiographic or sonographic image and the corresponding dictated report can then be 'linked' together. The description of the finding or findings of interest on the digitized image is thus electronically tethered to the image. This obviates the need to write much additional detail concerning the radiograph, saving time. In addition, the text on this disk can be indexed such that all files with user specified features can be instantly retrieve and combined in a single report, if desired. With the use of newer image compression techniques, hundreds of cases may be stored on a single CD-ROM depending on the quality of image required for the finding in question. This reduces the weight of a teaching file from that of a baby elephant to that of a single CD-ROM disc. Thus, with this method of teaching file preparation and storage the following advantages are realized: (1) Technically easier and less time consuming image reproduction. (2) Considerably less unwieldy and substantially more portable teaching files. (3) Novel ability to index files and then retrieve specific cases of choice based on descriptive text.

Intraoperative conjoined lumbosacral nerve roots associated with spondylolisthesis.

PubMed

Popa, Iulian; Poenaru, Dan V; Oprea, Manuel D; Andrei, Diana

2013-07-01

Lumbosacral nerve roots anomalies may produce low back pain. These anomalies are reported to be a cause for failed back surgery. They are usually left undiagnosed, especially in endoscopic discectomy techniques. Any surgery for entrapment disorders, performed on a patient with undiagnosed lumbosacral nerve roots anomaly, may lead to serious neural injuries because of an improper surgical technique or decompression. In this report, we describe our experience with a case of L5-S1 spondylolisthesis and associated congenital lumbosacral nerve root anomalies discovered during the surgical intervention, and the difficulties raised by such a discovery. Careful examination of coronal and axial views obtained through high-quality Magnetic Resonance Imaging may lead to a proper diagnosis of this condition leading to an adequate surgical planning, minimizing the intraoperatory complications.

Remote sensing of water quality and contaminants in the California Bay-Delta

NASA Astrophysics Data System (ADS)

Fichot, C. G.; Downing, B. D.; Windham-Myers, L.; Marvin-DiPasquale, M. C.; Bergamaschi, B. A.; Thompson, D. R.; Gierach, M. M.

2014-12-01

The California Bay-Delta is a highly altered ecosystem largely reclaimed from wetlands for agriculture, and millions of acres of farmland and Californians rely on the Bay-Delta for their water supply. The Bay-Delta also harbors important habitats for many organisms, including commercial and endangered species. Recently, the Delta Stewardship Council developed a two component mission (coequal goals) to 1) provide a more reliable water supply for California while 2) protecting, restoring, and enhancing the Bay-Delta ecosystem. Dissolved organic carbon, turbidity, and contaminants such as methylmercury represent important water quality issues for water management and in the context of wetland restoration in the Bay-Delta, and can threaten the achievement of the coequal goals. Here, we use field measurements of optical properties, chemical analyses, and remotely sensed data acquired with the airborne Portable Remote Imaging SpectroMeter (PRISM ; http://prism.jpl.nasa.gov/index.html) to demonstrate these water quality parameters and the study of their dynamics in the Bay-Delta are amenable to remote sensing. PRISM provides high signal-to-noise, high spatial resolution (~2 m), hyperspectral measurements of remote-sensing reflectance in the 350-1050 nm range, and therefore has the adequate resolutions for water quality monitoring in inland, optically complex waters. Remote sensing of water quality will represent a valuable complement to existing in situ water quality monitoring programs in this region and will help with decision-making to achieve the co-equal goals.

Remote Sensing Image Quality Assessment Experiment with Post-Processing

NASA Astrophysics Data System (ADS)

Jiang, W.; Chen, S.; Wang, X.; Huang, Q.; Shi, H.; Man, Y.

2018-04-01

This paper briefly describes the post-processing influence assessment experiment, the experiment includes three steps: the physical simulation, image processing, and image quality assessment. The physical simulation models sampled imaging system in laboratory, the imaging system parameters are tested, the digital image serving as image processing input are produced by this imaging system with the same imaging system parameters. The gathered optical sampled images with the tested imaging parameters are processed by 3 digital image processes, including calibration pre-processing, lossy compression with different compression ratio and image post-processing with different core. Image quality assessment method used is just noticeable difference (JND) subject assessment based on ISO20462, through subject assessment of the gathered and processing images, the influence of different imaging parameters and post-processing to image quality can be found. The six JND subject assessment experimental data can be validated each other. Main conclusions include: image post-processing can improve image quality; image post-processing can improve image quality even with lossy compression, image quality with higher compression ratio improves less than lower ratio; with our image post-processing method, image quality is better, when camera MTF being within a small range.

The impact of age on the art of mammography and how to adapt accordingly.

PubMed

Lake, B; Cielecki, L; Williams, S; Worrall, C; Metelko, M

2017-11-01

Breast cancer is increasingly a disease of the elderly, and combined with the NHS Breast Screening Extension means that more elderly patients are having mammography. Increasing age can make mammography more technically difficult. This is a technical note detailing the results of a local audit which may be of interest due to potential service implications. A retrospective audit of the first year of screening extension of The Shropshire Breast Screening Programme. Aims to collect data on patient demographics and describe the technical adaptations developed in Shropshire. Breast screening extension has increased by 2.5 times the number of women aged 70-74 screened, and doubled the overall numbers of women over 70 screened. Significantly more older patients are being screened to present technical challenges to a screening programme. Data was obtained from a month of screening showed that 29% of patients over 70 needed extra time for positioning. Reasons included 22% difficulty in obtaining adequate positioning and 15% needed a relative to aid with consent. In the Shropshire screening programme different technical adaptations have been developed and are key to ensuring adequate images. These include double appointments, two radiographers, thorough assessment, steeper angles, seated examinations, from-below imaging and pre-planning for subsequent screen. Significantly more older women are having breast screening due to the increasing incidence of breast cancer and the Breast Screening Programme extension. Increasing age can significantly increase time taken for adequate imaging and present technical challenges. Development of technical adaptations to art of mammography is key to achieve adequate images. Copyright © 2017 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.

Advances in phakic intraocular lenses: indications, efficacy, safety, and new designs.

PubMed

Alio, Jorge L

2004-08-01

The recent evolution of phakic intraocular lenses (PIOLs) has made this refractive surgical technique safer, very predictable, and effective. Due to these reasons, PIOLs have been expanding the horizon of their indications. The aim of this review is to update the reader in the recent advances reported on the topic during the year 2003. The most recent progress has been made towards decreasing the incision size down to 3 mm or less for all PIOLs models to avoid pupil ovalling in angle-supported designs with new biomaterials or exchangeable haptics, and to decrease the incidence of cataract induction in posterior chamber models with modified designs and better sizing. High-order aberrations and the quality of vision are improved with PIOLs. The main limitation for the further development of PIOLs is the lack of adequate diagnostic imaging techniques to perform a precise preoperative study of the anterior segment anatomy. Emerging diagnostic technologies based on the use of very high frequency (100 MHz) ultrasound and optical coherence tomography seem to have a most important role in the future development of PIOLs defining preoperatively the most adequate anatomic conditions for each design. PIOLs offer today an excellent alternative for the correction of high and moderate myopia, hyperopia, and astigmatism. Emerging indications, still under investigation, include presbyopia and pediatric anisometropic amblyopia. Due to their advantages for quality of vision and the increased knowledge on their safety, as well as the evidence of their predictability, PIOLs are expected to largely increase their clinical use as a refractive surgical technique in the coming years.

76 FR 65515 - Agency Information Collection Activities: Proposed Collection; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-21

... evaluation is determining participant quality of life and how the program affects quality of life. Medicaid... adequately meet their needs or does not provide them a suitable quality of life. State Operational Protocols... national evaluation contractor to assess program outcomes. The MFP Quality of Life data will be used by the...

The effect of image sharpness on quantitative eye movement data and on image quality evaluation while viewing natural images

NASA Astrophysics Data System (ADS)

Vuori, Tero; Olkkonen, Maria

2006-01-01

The aim of the study is to test both customer image quality rating (subjective image quality) and physical measurement of user behavior (eye movements tracking) to find customer satisfaction differences in imaging technologies. Methodological aim is to find out whether eye movements could be quantitatively used in image quality preference studies. In general, we want to map objective or physically measurable image quality to subjective evaluations and eye movement data. We conducted a series of image quality tests, in which the test subjects evaluated image quality while we recorded their eye movements. Results show that eye movement parameters consistently change according to the instructions given to the user, and according to physical image quality, e.g. saccade duration increased with increasing blur. Results indicate that eye movement tracking could be used to differentiate image quality evaluation strategies that the users have. Results also show that eye movements would help mapping between technological and subjective image quality. Furthermore, these results give some empirical emphasis to top-down perception processes in image quality perception and evaluation by showing differences between perceptual processes in situations when cognitive task varies.

Comorbidity structure of psychological disorders in the online e-PASS data as predictors of psychosocial adjustment measures: psychological distress, adequate social support, self-confidence, quality of life, and suicidal ideation.

PubMed

Al-Asadi, Ali M; Klein, Britt; Meyer, Denny

2014-10-28

A relative newcomer to the field of psychology, e-mental health has been gaining momentum and has been given considerable research attention. Although several aspects of e-mental health have been studied, 1 aspect has yet to receive attention: the structure of comorbidity of psychological disorders and their relationships with measures of psychosocial adjustment including suicidal ideation in online samples. This exploratory study attempted to identify the structure of comorbidity of 21 psychological disorders assessed by an automated online electronic psychological assessment screening system (e-PASS). The resulting comorbidity factor scores were then used to assess the association between comorbidity factor scores and measures of psychosocial adjustments (ie, psychological distress, suicidal ideation, adequate social support, self-confidence in dealing with mental health issues, and quality of life). A total of 13,414 participants were assessed using a complex online algorithm that resulted in primary and secondary Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision) diagnoses for 21 psychological disorders on dimensional severity scales. The scores on these severity scales were used in a principal component analysis (PCA) and the resulting comorbidity factor scores were related to 4 measures of psychosocial adjustments. A PCA based on 17 of the 21 psychological disorders resulted in a 4-factor model of comorbidity: anxiety-depression consisting of all anxiety disorders, major depressive episode (MDE), and insomnia; substance abuse consisting of alcohol and drug abuse and dependency; body image-eating consisting of eating disorders, body dysmorphic disorder, and obsessive-compulsive disorders; depression-sleep problems consisting of MDE, insomnia, and hypersomnia. All comorbidity factor scores were significantly associated with psychosocial measures of adjustment (P<.001). They were positively related to psychological distress and suicidal ideation, but negatively related to adequate social support, self-confidence, and quality of life. This exploratory study identified 4 comorbidity factors in the e-PASS data and these factor scores significantly predicted 5 psychosocial adjustment measures. Australian and New Zealand Clinical Trials Registry ACTRN121611000704998; http://www.anzctr.org.au/trial_view.aspx?ID=336143 (Archived by WebCite at http://www.webcitation.org/618r3wvOG).

Teaching an Integrated Science Curriculum: Linking Teacher Knowledge and Teaching Assignments

ERIC Educational Resources Information Center

Harrell, Pamela Esprivalo

2010-01-01

A number of factors affect successful implementation of an integrated science curriculum, including various outputs and inputs related to teacher quality such as professional development experiences, adequate planning periods, and adequate content preparation of teachers with regard to content knowledge associated with the curriculum taught. This…

76 FR 43136 - Approval and Promulgation of Air Quality Implementation Plan; Kentucky; Disapproval of Interstate...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-20

... supported by an adequate technical analysis. Second, EPA recommended the various types of information that... technical analysis, including, but not limited to, information concerning emissions in the state...: ``* * * without an adequate technical analysis EPA does not believe that states can sufficiently address the...

42 CFR 438.207 - Assurances of adequate capacity and services.

Code of Federal Regulations, 2010 CFR

2010-10-01

... HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS MANAGED CARE Quality Assessment and Performance Improvement Access Standards § 438.207 Assurances of adequate capacity and services. (a) Basic rule. The State... with the State's requirements for availability of services, as set forth in § 438.206. (e) CMS' right...

Impact of sampling techniques on measured stormwater quality data for small streams

USDA-ARS?s Scientific Manuscript database

Science-based sampling methodologies are needed to enhance water quality characterization for developing Total Maximum Daily Loads (TMDLs), setting appropriate water quality standards, and managing nonpoint source pollution. Storm event sampling, which is vital for adequate assessment of water qual...

Automatic retinal interest evaluation system (ARIES).

PubMed

Yin, Fengshou; Wong, Damon Wing Kee; Yow, Ai Ping; Lee, Beng Hai; Quan, Ying; Zhang, Zhuo; Gopalakrishnan, Kavitha; Li, Ruoying; Liu, Jiang

2014-01-01

In recent years, there has been increasing interest in the use of automatic computer-based systems for the detection of eye diseases such as glaucoma, age-related macular degeneration and diabetic retinopathy. However, in practice, retinal image quality is a big concern as automatic systems without consideration of degraded image quality will likely generate unreliable results. In this paper, an automatic retinal image quality assessment system (ARIES) is introduced to assess both image quality of the whole image and focal regions of interest. ARIES achieves 99.54% accuracy in distinguishing fundus images from other types of images through a retinal image identification step in a dataset of 35342 images. The system employs high level image quality measures (HIQM) to perform image quality assessment, and achieves areas under curve (AUCs) of 0.958 and 0.987 for whole image and optic disk region respectively in a testing dataset of 370 images. ARIES acts as a form of automatic quality control which ensures good quality images are used for processing, and can also be used to alert operators of poor quality images at the time of acquisition.

Naturalness and interestingness of test images for visual quality evaluation

NASA Astrophysics Data System (ADS)

Halonen, Raisa; Westman, Stina; Oittinen, Pirkko

2011-01-01

Balanced and representative test images are needed to study perceived visual quality in various application domains. This study investigates naturalness and interestingness as image quality attributes in the context of test images. Taking a top-down approach we aim to find the dimensions which constitute naturalness and interestingness in test images and the relationship between these high-level quality attributes. We compare existing collections of test images (e.g. Sony sRGB images, ISO 12640 images, Kodak images, Nokia images and test images developed within our group) in an experiment combining quality sorting and structured interviews. Based on the data gathered we analyze the viewer-supplied criteria for naturalness and interestingness across image types, quality levels and judges. This study advances our understanding of subjective image quality criteria and enables the validation of current test images, furthering their development.

Evaluation of the visual performance of image processing pipes: information value of subjective image attributes

NASA Astrophysics Data System (ADS)

Nyman, G.; Häkkinen, J.; Koivisto, E.-M.; Leisti, T.; Lindroos, P.; Orenius, O.; Virtanen, T.; Vuori, T.

2010-01-01

Subjective image quality data for 9 image processing pipes and 8 image contents (taken with mobile phone camera, 72 natural scene test images altogether) from 14 test subjects were collected. A triplet comparison setup and a hybrid qualitative/quantitative methodology were applied. MOS data and spontaneous, subjective image quality attributes to each test image were recorded. The use of positive and negative image quality attributes by the experimental subjects suggested a significant difference between the subjective spaces of low and high image quality. The robustness of the attribute data was shown by correlating DMOS data of the test images against their corresponding, average subjective attribute vector length data. The findings demonstrate the information value of spontaneous, subjective image quality attributes in evaluating image quality at variable quality levels. We discuss the implications of these findings for the development of sensitive performance measures and methods in profiling image processing systems and their components, especially at high image quality levels.

Is carbon dioxide a safe and good alternative for diatrizoate meglumine as a contrast in digital subtraction angiography?

PubMed Central

Hegde, U. N.; Khanapet, M. S.; Rajapurkar, M. M.; Gang, S. D.; Gohel, K. D.; Rane, G.; Parikh, P.; Patil, D.; Desai, T.; Patil, P.; Kelawala, N.

2009-01-01

Contrast-induced nephropathy is well-known sequelae of iodinated contrast (diatrizoate meglumine). Carbon dioxide (CO2) can be used as an alternative contrast agent. The aim of this study was to compare the renal injury and the quality of images of aortogram using iodinated contrast versus CO2 using digital subtraction angiography (DSA). This prospective randomized study was done in 29 healthy dogs using DSA aortogram. Dogs were randomly assigned to receive iodinated contrast or CO2. 6-F pigtail catheter was introduced via femoral artery approach to perform aortogram under general anesthesia. Serum creatinine (S.Cr.) and urinary enzymes, namely: N-acetyl D-glucosaminidase (NAG), alanine aminopeptidase (AAP), and gamma glutamyl transferase (GGT), were measured before and 48 hours after aortogram. There was no change in S.Cr. in both the groups. Significantly more enzymuria was seen following iodinated contrast than CO2. Enzymuria pre and postaortogram following the iodinated contrast was GGT: 14.9 ± 5.92 vs. 26.2 ± 15.1 (P = 0.001), NAG: 1.63 ± 0.90 vs. 3.6 ± 2.14 (P = 0.0001), and AAP: 1.51 ± 0.75 vs. 3.38 2.41 (P = 0.001), and in the CO2 group was GGT: 15.5 ± 4.9 vs. 21.1 ± 9.04 (P = 0.02), NAG: 2.12 ± 1.06 vs. 3.82 3.27 (P = 0.08), and AAP: 1.28 ± 0.76 vs. 2.51 ± 1.72 (P = 0.03). More than 50% increase over the preprocedural value was significantly less following CO2. Images obtained with iodinated contrast were superior to those with CO2, however, the quality of image with CO2 was adequate for delineation of the renal artery and major branches. Both iodinated contrast and CO2 cause significant enzymuria. More severe enzymuria (>50% increase) was seen significantly less with the use of CO2. Quality of images is better with iodinated contrast. PMID:20352006

How many CT detector rows are necessary to perform adequate three dimensional visualization?

PubMed

Fischer, Lars; Tetzlaff, Ralf; Schöbinger, Max; Radeleff, Boris; Bruckner, Thomas; Meinzer, H P; Büchler, M W; Schemmer, Peter

2010-06-01

The technical development of computer tomography (CT) imaging has experienced great progress. As consequence, CT data to be used for 3D visualization is not only based on 4 row CTs and 16 row CTs but also on 64 row CTs, respectively. The main goal of this study was to examine whether the increased amount of CT detector rows is correlated with improved quality of the 3D images. All CTs were acquired during routinely performed preoperative evaluation. Overall, there were 12 data sets based on 4 detector row CT, 12 data sets based on 16 detector row CT, and 10 data sets based on 64 detector row CT. Imaging data sets were transferred to the DKFZ Heidelberg using the CHILI teleradiology system. For the analysis all CT scans were examined in a blinded fashion, i.e. both the name of the patient as well as the name of the CT brand were erased. For analysis, the time for segmentation of liver, both portal and hepatic veins as well as the branching depth of portal veins and hepatic veins was recorded automatically. In addition, all results were validated in a blinded fashion based on given quality index. Segmentation of the liver was performed in significantly shorter time (p<0.01, Kruskal-Wallis test) in the 16 row CT (median 479 s) compared to 4 row CT (median 611 s), and 64 row CT (median 670 s), respectively. The branching depth of the portal vein did not differ significantly among the 3 different data sets (p=0.37, Kruskal-Wallis test). However, the branching depth of the hepatic veins was significantly better (p=0.028, Kruskal-Wallis test) in the 4 row CT and 16 row CT compared to 64 row CT. The grading of the quality index was not statistically different for portal veins and hepatic veins (p=0.80, Kruskal-Wallis test). Even though the total quality index was better for the vessel tree based on 64 row CT data sets (mean scale 2.6) compared to 4 CT row data (mean scale 3.25) and 16 row CT data (mean scale 3.0), these differences did not reach statistical difference (p=0.53, Kruskal-Wallis test). Even though 3D visualization is useful in operation planning, the quality of the 3D images appears to be not dependent of the number of CT detector rows. Copyright (c) 2009. Published by Elsevier Ireland Ltd.

Radiometer uncertainty equation research of 2D planar scanning PMMW imaging system

NASA Astrophysics Data System (ADS)

Hu, Taiyang; Xu, Jianzhong; Xiao, Zelong

2009-07-01

With advances in millimeter-wave technology, passive millimeter-wave (PMMW) imaging technology has received considerable concerns, and it has established itself in a wide range of military and civil practical applications, such as in the areas of remote sensing, blind landing, precision guidance and security inspection. Both the high transparency of clothing at millimeter wavelengths and the spatial resolution required to generate adequate images combine to make imaging at millimeter wavelengths a natural approach of screening people for concealed contraband detection. And at the same time, the passive operation mode does not present a safety hazard to the person who is under inspection. Based on the description to the design and engineering implementation of a W-band two-dimensional (2D) planar scanning imaging system, a series of scanning methods utilized in PMMW imaging are generally compared and analyzed, followed by a discussion on the operational principle of the mode of 2D planar scanning particularly. Furthermore, it is found that the traditional radiometer uncertainty equation, which is derived from a moving platform, does not hold under this 2D planar scanning mode due to the fact that there is no absolute connection between the scanning rates in horizontal direction and vertical direction. Consequently, an improved radiometer uncertainty equation is carried out in this paper, by means of taking the total time spent on scanning and imaging into consideration, with the purpose of solving the problem mentioned above. In addition, the related factors which affect the quality of radiometric images are further investigated under the improved radiometer uncertainty equation, and ultimately some original results are presented and analyzed to demonstrate the significance and validity of this new methodology.

Multiphase contrast medium injection for optimization of computed tomographic coronary angiography.

PubMed

Budoff, Matthew Jay; Shinbane, Jerold S; Child, Janis; Carson, Sivi; Chau, Alex; Liu, Stephen H; Mao, SongShou

2006-02-01

Electron beam angiography is a minimally invasive imaging technique. Adequate vascular opacification throughout the study remains a critical issue for image quality. We hypothesized that vascular image opacification and uniformity of vascular enhancement between slices can be improved using multiphase contrast medium injection protocols. We enrolled 244 consecutive patients who were randomized to three different injection protocols: single-phase contrast medium injection (Group 1), dual-phase contrast medium injection with each phase at a different injection rate (Group 2), and a three-phase injection with two phases of contrast medium injection followed by a saline injection phase (Group 3). Parameters measured were aortic opacification based on Hounsfield units and uniformity of aortic enhancement at predetermined slices (locations from top [level 1] to base [level 60]). In Group 1, contrast opacification differed across seven predetermined locations (scan levels: 1st versus 60th, P < .05), demonstrating significant nonuniformity. In Group 2, there was more uniform vascular enhancement, with no significant differences between the first 50 slices (P > .05). In Group 3, there was greater uniformity of vascular enhancement and higher mean Hounsfield units value across all 60 images, from the aortic root to the base of the heart (P < .05). The three-phase injection protocol improved vascular opacification at the base of the heart, as well as uniformity of arterial enhancement throughout the study.

Predictive validity of granulation tissue color measured by digital image analysis for deep pressure ulcer healing: a multicenter prospective cohort study.

PubMed

Iizaka, Shinji; Kaitani, Toshiko; Sugama, Junko; Nakagami, Gojiro; Naito, Ayumi; Koyanagi, Hiroe; Konya, Chizuko; Sanada, Hiromi

2013-01-01

This multicenter prospective cohort study examined the predictive validity of granulation tissue color evaluated by digital image analysis for deep pressure ulcer healing. Ninety-one patients with deep pressure ulcers were followed for 3 weeks. From a wound photograph taken at baseline, an image representing the granulation red index (GRI) was processed in which a redder color represented higher values. We calculated the average GRI over granulation tissue and the proportion of pixels exceeding the threshold intensity of 80 for the granulation tissue surface (%GRI80) and wound surface (%wound red index 80). In the receiver operating characteristics curve analysis, most GRI parameters had adequate discriminative values for both improvement of the DESIGN-R total score and wound closure. Ulcers were categorized by the obtained cutoff points of the average GRI (≤80, >80), %GRI80 (≤55, >55-80, >80%), and %wound red index 80 (≤25, >25-50, >50%). In the linear mixed model, higher classes for all GRI parameters showed significantly greater relative improvement in overall wound severity during the 3 weeks after adjustment for patient characteristics and wound locations. Assessment of granulation tissue color by digital image analysis will be useful as an objective monitoring tool for granulation tissue quality or surrogate outcomes of pressure ulcer healing. © 2012 by the Wound Healing Society.

An Advanced Preclinical Mouse Model for Acute Myeloid Leukemia Using Patients' Cells of Various Genetic Subgroups and In Vivo Bioluminescence Imaging

PubMed Central

Vick, Binje; Rothenberg, Maja; Sandhöfer, Nadine; Carlet, Michela; Finkenzeller, Cornelia; Krupka, Christina; Grunert, Michaela; Trumpp, Andreas; Corbacioglu, Selim; Ebinger, Martin; André, Maya C.; Hiddemann, Wolfgang; Schneider, Stephanie; Subklewe, Marion; Metzeler, Klaus H.; Spiekermann, Karsten; Jeremias, Irmela

2015-01-01

Acute myeloid leukemia (AML) is a clinically and molecularly heterogeneous disease with poor outcome. Adequate model systems are required for preclinical studies to improve understanding of AML biology and to develop novel, rational treatment approaches. Xenografts in immunodeficient mice allow performing functional studies on patient-derived AML cells. We have established an improved model system that integrates serial retransplantation of patient-derived xenograft (PDX) cells in mice, genetic manipulation by lentiviral transduction, and essential quality controls by immunophenotyping and targeted resequencing of driver genes. 17/29 samples showed primary engraftment, 10/17 samples could be retransplanted and some of them allowed virtually indefinite serial transplantation. 5/6 samples were successfully transduced using lentiviruses. Neither serial transplantation nor genetic engineering markedly altered sample characteristics analyzed. Transgene expression was stable in PDX AML cells. Example given, recombinant luciferase enabled bioluminescence in vivo imaging and highly sensitive and reliable disease monitoring; imaging visualized minimal disease at 1 PDX cell in 10000 mouse bone marrow cells and facilitated quantifying leukemia initiating cells. We conclude that serial expansion, genetic engineering and imaging represent valuable tools to improve the individualized xenograft mouse model of AML. Prospectively, these advancements enable repetitive, clinically relevant studies on AML biology and preclinical treatment trials on genetically defined and heterogeneous subgroups. PMID:25793878

40 CFR Appendix C to Part 61 - Quality Assurance Procedures

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Quality Assurance Procedures C Appendix C to Part 61 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...—Quality Assurance Procedures Procedure 1—Determination of Adequate Chromatographic Peak Resolution In this...

SDL: Saliency-Based Dictionary Learning Framework for Image Similarity.

PubMed

Sarkar, Rituparna; Acton, Scott T

2018-02-01

In image classification, obtaining adequate data to learn a robust classifier has often proven to be difficult in several scenarios. Classification of histological tissue images for health care analysis is a notable application in this context due to the necessity of surgery, biopsy or autopsy. To adequately exploit limited training data in classification, we propose a saliency guided dictionary learning method and subsequently an image similarity technique for histo-pathological image classification. Salient object detection from images aids in the identification of discriminative image features. We leverage the saliency values for the local image regions to learn a dictionary and respective sparse codes for an image, such that the more salient features are reconstructed with smaller error. The dictionary learned from an image gives a compact representation of the image itself and is capable of representing images with similar content, with comparable sparse codes. We employ this idea to design a similarity measure between a pair of images, where local image features of one image, are encoded with the dictionary learned from the other and vice versa. To effectively utilize the learned dictionary, we take into account the contribution of each dictionary atom in the sparse codes to generate a global image representation for image comparison. The efficacy of the proposed method was evaluated using three tissue data sets that consist of mammalian kidney, lung and spleen tissue, breast cancer, and colon cancer tissue images. From the experiments, we observe that our methods outperform the state of the art with an increase of 14.2% in the average classification accuracy over all data sets.

Adaptive distance metric learning for diffusion tensor image segmentation.

PubMed

Kong, Youyong; Wang, Defeng; Shi, Lin; Hui, Steve C N; Chu, Winnie C W

2014-01-01

High quality segmentation of diffusion tensor images (DTI) is of key interest in biomedical research and clinical application. In previous studies, most efforts have been made to construct predefined metrics for different DTI segmentation tasks. These methods require adequate prior knowledge and tuning parameters. To overcome these disadvantages, we proposed to automatically learn an adaptive distance metric by a graph based semi-supervised learning model for DTI segmentation. An original discriminative distance vector was first formulated by combining both geometry and orientation distances derived from diffusion tensors. The kernel metric over the original distance and labels of all voxels were then simultaneously optimized in a graph based semi-supervised learning approach. Finally, the optimization task was efficiently solved with an iterative gradient descent method to achieve the optimal solution. With our approach, an adaptive distance metric could be available for each specific segmentation task. Experiments on synthetic and real brain DTI datasets were performed to demonstrate the effectiveness and robustness of the proposed distance metric learning approach. The performance of our approach was compared with three classical metrics in the graph based semi-supervised learning framework.

Adaptive Distance Metric Learning for Diffusion Tensor Image Segmentation

PubMed Central

Kong, Youyong; Wang, Defeng; Shi, Lin; Hui, Steve C. N.; Chu, Winnie C. W.

2014-01-01

High quality segmentation of diffusion tensor images (DTI) is of key interest in biomedical research and clinical application. In previous studies, most efforts have been made to construct predefined metrics for different DTI segmentation tasks. These methods require adequate prior knowledge and tuning parameters. To overcome these disadvantages, we proposed to automatically learn an adaptive distance metric by a graph based semi-supervised learning model for DTI segmentation. An original discriminative distance vector was first formulated by combining both geometry and orientation distances derived from diffusion tensors. The kernel metric over the original distance and labels of all voxels were then simultaneously optimized in a graph based semi-supervised learning approach. Finally, the optimization task was efficiently solved with an iterative gradient descent method to achieve the optimal solution. With our approach, an adaptive distance metric could be available for each specific segmentation task. Experiments on synthetic and real brain DTI datasets were performed to demonstrate the effectiveness and robustness of the proposed distance metric learning approach. The performance of our approach was compared with three classical metrics in the graph based semi-supervised learning framework. PMID:24651858

[Interventional radiology for bone metastases].

PubMed

Iannessi, Antoine; Garnon, Julien; Cormier, Évelyne; Clarencon, Frédéric; Chiras, Jacques

2013-11-01

The management of bone metastases requires a multidisciplinary staff to include systemic and local treatments like radiotherapy, surgery or interventional radiology (IR). Patients are often fragile. Imaging allows safe guidance to create "mini-invasive" procedures under adequate anesthesia. Patients' selection is important. If the goal is pain relief, cementoplasty provides a very effective bone consolidation and pain control. Simple and low-risk, vertebroplasty is the technique of choice in case of lytic bone metastases with spinal fracture risk or after failure of analgesic radiotherapy. If the medical project is curative, the tumor ablation procedures are realised through thermic or embolic techniques. After 60°C, the heat induces a coagulative necrose. Under -20°C, the cold leads to destroy the tissues. The major advantage of the cryotherapy is the predictibility of the ablation zone due to the well-visualized ice ball on perprocedural images. This technique is much more adapted to spare the nervous structures closed to the metastasis. The development of these new techniques of IR will treat bone metastases earlier, sometimes asymptomatic and thus improves the quality of life in patients with bone metastases.

Advanced multispectral dynamic thermography as a new tool for inspection of gas-fired furnaces

NASA Astrophysics Data System (ADS)

Pregowski, Piotr; Goleniewski, Grzegorz; Komosa, Wojciech; Korytkowski, Waldemar

2004-04-01

The main special feature of elaborated method is that the dynamic IR thermography (DIRT) bases on forming of single image consisting of pixels of chosen minimum (IMAX) or maximum (IMAX) value, noted during adequately long sequence of thermograms with total independence to the moment of its (image's) capture. In this way, additive or suppressed interferences of fluctuating character become bypassed. Due to this method thereafter elaborated in classic way such "artificial thermogram" offers the quality impossible to achieve with a classic "one shot" method. Although preliminary, results obtained clearly show great potential of the method. and confirmed the validity in decreasing errors caused by fluctuating disturbances. In the case of process furnaces of gas-fired type and especially of coal-fired, application of presented solutions should result in significant increasing the reliability of IR thermography application. By use of properly chosen optical filters and algorithm, elaborated method offers a new potential attractive to test temperature problems other than in tubes , as for example symmetry and efficiency of the furnace heaters.

Diet quality of Italian yogurt consumers: an application of the probability of adequate nutrient intake score (PANDiet).

PubMed

Mistura, Lorenza; D'Addezio, Laura; Sette, Stefania; Piccinelli, Raffaela; Turrini, Aida

2016-01-01

The diet quality in yogurt consumers and non-consumers was evaluated by applying the probability of adequate nutrient intake (PANDiet) index to a sample of adults and elderly from the Italian food consumption survey INRAN SCAI 2005-06. Overall, yogurt consumers had a significantly higher mean intake of energy, calcium and percentage of energy from total sugars whereas the mean percentage of energy from total fat, saturated fatty acid and total carbohydrate were significantly (p < 0.01) lower than in non-consumers. The PANDiet index was significantly higher in yogurt consumers than in non-consumers, (60.58 ± 0.33 vs. 58.58 ± 0.19, p < 0.001). The adequacy sub-score for 17 nutrients for which usual intake should be above the reference value was significantly higher among yogurt consumers. The items of calcium, potassium and riboflavin showed the major percentage variation between consumers and non-consumers. Yogurt consumers were more likely to have adequate intakes of vitamins and minerals, and a higher quality score of the diet.

Noise Estimation and Quality Assessment of Gaussian Noise Corrupted Images

NASA Astrophysics Data System (ADS)

Kamble, V. M.; Bhurchandi, K.

2018-03-01

Evaluating the exact quantity of noise present in an image and quality of an image in the absence of reference image is a challenging task. We propose a near perfect noise estimation method and a no reference image quality assessment method for images corrupted by Gaussian noise. The proposed methods obtain initial estimate of noise standard deviation present in an image using the median of wavelet transform coefficients and then obtains a near to exact estimate using curve fitting. The proposed noise estimation method provides the estimate of noise within average error of +/-4%. For quality assessment, this noise estimate is mapped to fit the Differential Mean Opinion Score (DMOS) using a nonlinear function. The proposed methods require minimum training and yields the noise estimate and image quality score. Images from Laboratory for image and Video Processing (LIVE) database and Computational Perception and Image Quality (CSIQ) database are used for validation of the proposed quality assessment method. Experimental results show that the performance of proposed quality assessment method is at par with the existing no reference image quality assessment metric for Gaussian noise corrupted images.

Quantitative evaluation of susceptibility effects caused by dental materials in head magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Strocchi, S.; Ghielmi, M.; Basilico, F.; Macchi, A.; Novario, R.; Ferretti, R.; Binaghi, E.

2016-03-01

This work quantitatively evaluates the effects induced by susceptibility characteristics of materials commonly used in dental practice on the quality of head MR images in a clinical 1.5T device. The proposed evaluation procedure measures the image artifacts induced by susceptibility in MR images by providing an index consistent with the global degradation as perceived by the experts. Susceptibility artifacts were evaluated in a near-clinical setup, using a phantom with susceptibility and geometric characteristics similar to that of a human head. We tested different dentist materials, called PAL Keramit, Ti6Al4V-ELI, Keramit NP, ILOR F, Zirconia and used different clinical MR acquisition sequences, such as "classical" SE and fast, gradient, and diffusion sequences. The evaluation is designed as a matching process between reference and artifacts affected images recording the same scene. The extent of the degradation induced by susceptibility is then measured in terms of similarity with the corresponding reference image. The matching process involves a multimodal registration task and the use an adequate similarity index psychophysically validated, based on correlation coefficient. The proposed analyses are integrated within a computer-supported procedure that interactively guides the users in the different phases of the evaluation method. 2-Dimensional and 3-dimensional indexes are used for each material and each acquisition sequence. From these, we drew a ranking of the materials, averaging the results obtained. Zirconia and ILOR F appear to be the best choice from the susceptibility artefacts point of view, followed, in order, by PAL Keramit, Ti6Al4V-ELI and Keramit NP.

Circuit design for the retina-like image sensor based on space-variant lens array

NASA Astrophysics Data System (ADS)

Gao, Hongxun; Hao, Qun; Jin, Xuefeng; Cao, Jie; Liu, Yue; Song, Yong; Fan, Fan

2013-12-01

Retina-like image sensor is based on the non-uniformity of the human eyes and the log-polar coordinate theory. It has advantages of high-quality data compression and redundant information elimination. However, retina-like image sensors based on the CMOS craft have drawbacks such as high cost, low sensitivity and signal outputting efficiency and updating inconvenience. Therefore, this paper proposes a retina-like image sensor based on space-variant lens array, focusing on the circuit design to provide circuit support to the whole system. The circuit includes the following parts: (1) A photo-detector array with a lens array to convert optical signals to electrical signals; (2) a strobe circuit for time-gating of the pixels and parallel paths for high-speed transmission of the data; (3) a high-precision digital potentiometer for the I-V conversion, ratio normalization and sensitivity adjustment, a programmable gain amplifier for automatic generation control(AGC), and a A/D converter for the A/D conversion in every path; (4) the digital data is displayed on LCD and stored temporarily in DDR2 SDRAM; (5) a USB port to transfer the data to PC; (6) the whole system is controlled by FPGA. This circuit has advantages as lower cost, larger pixels, updating convenience and higher signal outputting efficiency. Experiments have proved that the grayscale output of every pixel basically matches the target and a non-uniform image of the target is ideally achieved in real time. The circuit can provide adequate technical support to retina-like image sensors based on space-variant lens array.

77 FR 19192 - Circular Welded Carbon-Quality Steel Pipe From India: Preliminary Affirmative Countervailing Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-30

.... See Memorandum to Susan H. Kuhbach, Director, Office 1 from David Layton, International Trade Analyst... Provision of Hot-Rolled Steel by the Steel Authority of India (``SAIL'') for Less Than Adequate Remuneration... the questions regarding land received at less than adequate remuneration, Zenith prevented us from...

76 FR 14835 - Approval and Promulgation of Air Quality Implementation Plan; Missouri; Proposed Disapproval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-18

... the state's conclusion should be supported by an adequate technical analysis. EPA recommended the...)(2)(D)(i)(I) must be supported by an adequate technical analysis.\\5\\ EPA recommended the various..., the state did not further evaluate or demonstrate with a technical analysis that these measures...

76 FR 14831 - Approval and Promulgation of Air Quality Implementation Plan; Kansas; Proposed Disapproval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-18

... State's conclusion should be supported by an adequate technical analysis. EPA recommended the various...) must be supported by an adequate technical analysis.\\5\\ EPA recommended the various types of... evaluate or demonstrate with a technical analysis that these measures address the requirements of 110(a)(2...

76 FR 43175 - Approval of Air Quality Implementation Plans; Indiana and Ohio; Disapproval of Interstate...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-20

... impact. EPA stated that the state's conclusion should be supported by an adequate technical analysis. EPA... by an adequate technical analysis. IDEM did not provide a technical analysis in its submittal, but... technical analysis and justification necessary to make that demonstration. Indiana did not provide any...

76 FR 4592 - Approval and Promulgation of Air Quality Implementation Plan; North Carolina; Disapproval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-26

... adequate technical analysis. Second, EPA recommended the various types of information that could be... submission, it did not further evaluate or demonstrate with a technical analysis that this measure and their.... Unfortunately, without an adequate technical analysis EPA does not believe that states can sufficiently address...

30 CFR 74.6 - Quality control.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Quality control. 74.6 Section 74.6 Mineral... control. The applicant shall describe the way in which each lot of components will be sampled and tested... of the CMDPSU will be maintained in production through adequate quality control procedures, MSHA and...

Indoor Air Quality: Maryland Public Schools.

ERIC Educational Resources Information Center

Maryland State Dept. of Education, College Park. Office of Administration and Finance.

Less than adequate indoor air quality in schools can lead to a higher risk of health problems, an increase in student and teacher absenteeism, diminished learning, and even hazardous conditions. An indoor air quality program that addresses the planning, design, maintenance, and operation of public school buildings should be implemented at the…

30 CFR 74.6 - Quality control.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Quality control. 74.6 Section 74.6 Mineral... control. The applicant shall describe the way in which each lot of components will be sampled and tested... of the CMDPSU will be maintained in production through adequate quality control procedures, MSHA and...

30 CFR 74.6 - Quality control.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Quality control. 74.6 Section 74.6 Mineral... control. The applicant shall describe the way in which each lot of components will be sampled and tested... of the CMDPSU will be maintained in production through adequate quality control procedures, MSHA and...

Effects of foliar potassium fertilization on muskmelon fruit quality and yield

USDA-ARS?s Scientific Manuscript database

Consumer preference of many fruits and vegetables such as muskmelon [Cucumis melo L. (Reticulatus Group)] is determined by a few key quality traits such as sugar content, aroma and texture. These quality traits are directly related to adequate potassium (K) content in plant tissues. However, soil-...

Use of mobile high-resolution device for remote frozen section evaluation of whole slide images.

PubMed

Ramey, Joel; Fung, Kar Ming; Hassell, Lewis A

2011-01-01

With recent advances, it is now possible to view whole slide images (WSI) on mobile, high-resolution, viewing devices (MVD). This creates a new paradigm in which MVDs may be used for consultation and/or diagnosis. Validation of the results with devices is important for practitioners and regulators. We evaluated the use of MVDs in frozen section (FS) interpretation. A series of 72 consecutive FS cases were selected for potential inclusion in the study. A 67 case subset of these were successfully scanned at 20x magnification. Scan times were recorded. A sample of WSI FS cases, with gross and clinical information, was presented to six pathologists on an iPad MVD using the Interpath application. Times to diagnosis were recorded. Results were compared with the original reported and final diagnosis. Participants also completed a survey assessing image quality, interface, and diagnostic comfort level. Scan times averaged two minutes and 46 seconds per slide, (standard deviation [SD] 2 minutes 46 seconds). Evaluation times averaged 4 minutes and 59 seconds per case, range to 13 minutes and 50 seconds, SD 3 minutes 48 seconds. Concordance between initial FS diagnosis and rendered through the MVD was 89%. Minor discrepancies made up 8% and major disagreements 3%. The kappa statistic for this series is 0.85. Participants rated the experience at 5 on a 10-point scale, range 3 to 7. Two-thirds found the image quality to be adequate, half were satisfied with image resolution, and 33% would be willing to make a diagnosis on the iPad, plus one only for special cases. Five of six respondents (83%) found the navigation with the study software difficult. Image fidelity and resolution makes the iPad potentially suitable for WSI evaluation of FS. Acceptable accuracy is attainable for FS interpretation. But, although possible to obtain acceptable results, use of the iPad with Interpath to view WSI is not easy and meets user resistance. The obstacle of slide navigation at high magnification could introduce frustrations, delays, or errors.

TH-A-16A-01: Image Quality for the Radiation Oncology Physicist: Review of the Fundamentals and Implementation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seibert, J; Imbergamo, P

The expansion and integration of diagnostic imaging technologies such as On Board Imaging (OBI) and Cone Beam Computed Tomography (CBCT) into radiation oncology has required radiation oncology physicists to be responsible for and become familiar with assessing image quality. Unfortunately many radiation oncology physicists have had little or no training or experience in measuring and assessing image quality. Many physicists have turned to automated QA analysis software without having a fundamental understanding of image quality measures. This session will review the basic image quality measures of imaging technologies used in the radiation oncology clinic, such as low contrast resolution, highmore » contrast resolution, uniformity, noise, and contrast scale, and how to measure and assess them in a meaningful way. Additionally a discussion of the implementation of an image quality assurance program in compliance with Task Group recommendations will be presented along with the advantages and disadvantages of automated analysis methods. Learning Objectives: Review and understanding of the fundamentals of image quality. Review and understanding of the basic image quality measures of imaging modalities used in the radiation oncology clinic. Understand how to implement an image quality assurance program and to assess basic image quality measures in a meaningful way.« less

Selected water-quality characteristics in the upper Mississippi River basin, Royalton to Hastings, Minnesota

USGS Publications Warehouse

Have, M.R.

1991-01-01

Results of this study show that the quality of water in the Mississippi River as it leaves the accounting unit at Hastings is not representative of water quality in most of the accounting unit. Three water-quality regions have been identified, and sampling sites are needed in each region to assess the quality of streams throughout the study area adequately.

Feasibility of real-time echocardiographic evaluation during patient transport.

PubMed

Garrett, Paul D; Boyd, Sheri Y N; Bauch, Terry D; Rubal, Bernard J; Bulgrin, James R; Kinkler, E Sterling

2003-03-01

Echocardiography is a key diagnostic tool in evaluating patients with cardiac emergencies and chest trauma. The lack of qualified real-time interpretation limits its use by emergency first responders. Early diagnosis of cardiac emergencies has the potential to facilitate triage and medical intervention to improve outcomes. We investigated the feasibility of remote, real-time interpretation of echocardiograms during patient transport. Echocardiograms using a hand-carried ultrasound device were transmitted from an ambulance in transit to a tertiary care facility using a distributed mobile local area network. Transmitted studies were reviewed by a cardiologist for ability to interpret predefined features. Transmission quality and reliability were assessed. Echocardiographic images were successfully transmitted greater than 88% of transport time. The evaluation of left-ventricular size and function, and presence of pericardial effusion were greater than 90% concordant, but only 66% of all echocardiographic features were concordant. Most transmission losses were brief (

The effect of image quality, repeated study, and assessment method on anatomy learning.

PubMed

Fenesi, Barbara; Mackinnon, Chelsea; Cheng, Lucia; Kim, Joseph A; Wainman, Bruce C

2017-06-01

The use of two-dimensional (2D) images is consistently used to prepare anatomy students for handling real specimen. This study examined whether the quality of 2D images is a critical component in anatomy learning. The visual clarity and consistency of 2D anatomical images was systematically manipulated to produce low-quality and high-quality images of the human hand and human eye. On day 0, participants learned about each anatomical specimen from paper booklets using either low-quality or high-quality images, and then completed a comprehension test using either 2D images or three-dimensional (3D) cadaveric specimens. On day 1, participants relearned each booklet, and on day 2 participants completed a final comprehension test using either 2D images or 3D cadaveric specimens. The effect of image quality on learning varied according to anatomical content, with high-quality images having a greater effect on improving learning of hand anatomy than eye anatomy (high-quality vs. low-quality for hand anatomy P = 0.018; high-quality vs. low-quality for eye anatomy P = 0.247). Also, the benefit of high-quality images on hand anatomy learning was restricted to performance on short-answer (SA) questions immediately after learning (high-quality vs. low-quality on SA questions P = 0.018), but did not apply to performance on multiple-choice (MC) questions (high-quality vs. low-quality on MC questions P = 0.109) or after participants had an additional learning opportunity (24 hours later) with anatomy content (high vs. low on SA questions P = 0.643). This study underscores the limited impact of image quality on anatomy learning, and questions whether investment in enhancing image quality of learning aids significantly promotes knowledge development. Anat Sci Educ 10: 249-261. © 2016 American Association of Anatomists. © 2016 American Association of Anatomists.

Model-Based Normalization of a Fractional-Crystal Collimator for Small-Animal PET Imaging

PubMed Central

Li, Yusheng; Matej, Samuel; Karp, Joel S.; Metzler, Scott D.

2017-01-01

Previously, we proposed to use a coincidence collimator to achieve fractional-crystal resolution in PET imaging. We have designed and fabricated a collimator prototype for a small-animal PET scanner, A-PET. To compensate for imperfections in the fabricated collimator prototype, collimator normalization, as well as scanner normalization, is required to reconstruct quantitative and artifact-free images. In this study, we develop a normalization method for the collimator prototype based on the A-PET normalization using a uniform cylinder phantom. We performed data acquisition without the collimator for scanner normalization first, and then with the collimator from eight different rotation views for collimator normalization. After a reconstruction without correction, we extracted the cylinder parameters from which we generated expected emission sinograms. Single scatter simulation was used to generate the scattered sinograms. We used the least-squares method to generate the normalization coefficient for each LOR based on measured, expected and scattered sinograms. The scanner and collimator normalization coefficients were factorized by performing two normalizations separately. The normalization methods were also verified using experimental data acquired from A-PET with and without the collimator. In summary, we developed a model-base collimator normalization that can significantly reduce variance and produce collimator normalization with adequate statistical quality within feasible scan time. PMID:29270539

Model-Based Normalization of a Fractional-Crystal Collimator for Small-Animal PET Imaging.

PubMed

Li, Yusheng; Matej, Samuel; Karp, Joel S; Metzler, Scott D

2017-05-01

Previously, we proposed to use a coincidence collimator to achieve fractional-crystal resolution in PET imaging. We have designed and fabricated a collimator prototype for a small-animal PET scanner, A-PET. To compensate for imperfections in the fabricated collimator prototype, collimator normalization, as well as scanner normalization, is required to reconstruct quantitative and artifact-free images. In this study, we develop a normalization method for the collimator prototype based on the A-PET normalization using a uniform cylinder phantom. We performed data acquisition without the collimator for scanner normalization first, and then with the collimator from eight different rotation views for collimator normalization. After a reconstruction without correction, we extracted the cylinder parameters from which we generated expected emission sinograms. Single scatter simulation was used to generate the scattered sinograms. We used the least-squares method to generate the normalization coefficient for each LOR based on measured, expected and scattered sinograms. The scanner and collimator normalization coefficients were factorized by performing two normalizations separately. The normalization methods were also verified using experimental data acquired from A-PET with and without the collimator. In summary, we developed a model-base collimator normalization that can significantly reduce variance and produce collimator normalization with adequate statistical quality within feasible scan time.

Rotational electrical impedance tomography using electrodes with limited surface coverage provides window for multimodal sensing

NASA Astrophysics Data System (ADS)

Lehti-Polojärvi, Mari; Koskela, Olli; Seppänen, Aku; Figueiras, Edite; Hyttinen, Jari

2018-02-01

Electrical impedance tomography (EIT) is an imaging method that could become a valuable tool in multimodal applications. One challenge in simultaneous multimodal imaging is that typically the EIT electrodes cover a large portion of the object surface. This paper investigates the feasibility of rotational EIT (rEIT) in applications where electrodes cover only a limited angle of the surface of the object. In the studied rEIT, the object is rotated a full 360° during a set of measurements to increase the information content of the data. We call this approach limited angle full revolution rEIT (LAFR-rEIT). We test LAFR-rEIT setups in two-dimensional geometries with computational and experimental data. We use up to 256 rotational measurement positions, which requires a new way to solve the forward and inverse problem of rEIT. For this, we provide a modification, available for EIDORS, in the supplementary material. The computational results demonstrate that LAFR-rEIT with eight electrodes produce the same image quality as conventional 16-electrode rEIT, when data from an adequate number of rotational measurement positions are used. Both computational and experimental results indicate that the novel LAFR-rEIT provides good EIT with setups with limited surface coverage and a small number of electrodes.

The study of surgical image quality evaluation system by subjective quality factor method

NASA Astrophysics Data System (ADS)

Zhang, Jian J.; Xuan, Jason R.; Yang, Xirong; Yu, Honggang; Koullick, Edouard

2016-03-01

GreenLightTM procedure is an effective and economical way of treatment of benign prostate hyperplasia (BPH); there are almost a million of patients treated with GreenLightTM worldwide. During the surgical procedure, the surgeon or physician will rely on the monitoring video system to survey and confirm the surgical progress. There are a few obstructions that could greatly affect the image quality of the monitoring video, like laser glare by the tissue and body fluid, air bubbles and debris generated by tissue evaporation, and bleeding, just to name a few. In order to improve the physician's visual experience of a laser surgical procedure, the system performance parameter related to image quality needs to be well defined. However, since image quality is the integrated set of perceptions of the overall degree of excellence of an image, or in other words, image quality is the perceptually weighted combination of significant attributes (contrast, graininess …) of an image when considered in its marketplace or application, there is no standard definition on overall image or video quality especially for the no-reference case (without a standard chart as reference). In this study, Subjective Quality Factor (SQF) and acutance are used for no-reference image quality evaluation. Basic image quality parameters, like sharpness, color accuracy, size of obstruction and transmission of obstruction, are used as subparameter to define the rating scale for image quality evaluation or comparison. Sample image groups were evaluated by human observers according to the rating scale. Surveys of physician groups were also conducted with lab generated sample videos. The study shows that human subjective perception is a trustworthy way of image quality evaluation. More systematic investigation on the relationship between video quality and image quality of each frame will be conducted as a future study.

Achieving quality in cardiovascular imaging: proceedings from the American College of Cardiology-Duke University Medical Center Think Tank on Quality in Cardiovascular Imaging.

PubMed

Douglas, Pamela; Iskandrian, Ami E; Krumholz, Harlan M; Gillam, Linda; Hendel, Robert; Jollis, James; Peterson, Eric; Chen, Jersey; Masoudi, Frederick; Mohler, Emile; McNamara, Robert L; Patel, Manesh R; Spertus, John

2006-11-21

Cardiovascular imaging has enjoyed both rapid technological advances and sustained growth, yet less attention has been focused on quality than in other areas of cardiovascular medicine. To address this deficit, representatives from cardiovascular imaging societies, private payers, government agencies, the medical imaging industry, and experts in quality measurement met, and this report provides an overview of the discussions. A consensus definition of quality in imaging and a convergence of opinion on quality measures across imaging modalities was achieved and are intended to be the start of a process culminating in the development, dissemination, and adoption of quality measures for all cardiovascular imaging modalities.

An Efficient Framework for Compressed Sensing Reconstruction of Highly Accelerated Dynamic Cardiac MRI

NASA Astrophysics Data System (ADS)

Ting, Samuel T.

The research presented in this work seeks to develop, validate, and deploy practical techniques for improving diagnosis of cardiovascular disease. In the philosophy of biomedical engineering, we seek to identify an existing medical problem having significant societal and economic effects and address this problem using engineering approaches. Cardiovascular disease is the leading cause of mortality in the United States, accounting for more deaths than any other major cause of death in every year since 1900 with the exception of the year 1918. Cardiovascular disease is estimated to account for almost one-third of all deaths in the United States, with more than 2150 deaths each day, or roughly 1 death every 40 seconds. In the past several decades, a growing array of imaging modalities have proven useful in aiding the diagnosis and evaluation of cardiovascular disease, including computed tomography, single photon emission computed tomography, and echocardiography. In particular, cardiac magnetic resonance imaging is an excellent diagnostic tool that can provide within a single exam a high quality evaluation of cardiac function, blood flow, perfusion, viability, and edema without the use of ionizing radiation. The scope of this work focuses on the application of engineering techniques for improving imaging using cardiac magnetic resonance with the goal of improving the utility of this powerful imaging modality. Dynamic cine imaging, or the capturing of movies of a single slice or volume within the heart or great vessel region, is used in nearly every cardiac magnetic resonance imaging exam, and adequate evaluation of cardiac function and morphology for diagnosis and evaluation of cardiovascular disease depends heavily on both the spatial and temporal resolution as well as the image quality of the reconstruction cine images. This work focuses primarily on image reconstruction techniques utilized in cine imaging; however, the techniques discussed are also relevant to other dynamic and static imaging techniques based on cardiac magnetic resonance. Conventional segmented techniques for cardiac cine imaging require breath-holding as well as regular cardiac rhythm, and can be time-consuming to acquire. Inadequate breath-holding or irregular cardiac rhythm can result in completely non-diagnostic images, limiting the utility of these techniques in a significant patient population. Real-time single-shot cardiac cine imaging enables free-breathing acquisition with significantly shortened imaging time and promises to significantly improve the utility of cine imaging for diagnosis and evaluation of cardiovascular disease. However, utility of real-time cine images depends heavily on the successful reconstruction of final cine images from undersampled data. Successful reconstruction of images from more highly undersampled data results directly in images exhibiting finer spatial and temporal resolution provided that image quality is sufficient. This work focuses primarily on the development, validation, and deployment of practical techniques for enabling the reconstruction of real-time cardiac cine images at the spatial and temporal resolutions and image quality needed for diagnostic utility. Particular emphasis is placed on the development of reconstruction approaches resulting in with short computation times that can be used in the clinical environment. Specifically, the use of compressed sensing signal recovery techniques is considered; such techniques show great promise in allowing successful reconstruction of highly undersampled data. The scope of this work concerns two primary topics related to signal recovery using compressed sensing: (1) long reconstruction times of these techniques, and (2) improved sparsity models for signal recovery from more highly undersampled data. Both of these aspects are relevant to the practical application of compressed sensing techniques in the context of improving image reconstruction of real-time cardiac cine images. First, algorithmic and implementational approaches are proposed for reducing the computational time for a compressed sensing reconstruction framework. Specific optimization algorithms based on the fast iterative/shrinkage algorithm (FISTA) are applied in the context of real-time cine image reconstruction to achieve efficient per-iteration computation time. Implementation within a code framework utilizing commercially available graphics processing units (GPUs) allows for practical and efficient implementation directly within the clinical environment. Second, patch-based sparsity models are proposed to enable compressed sensing signal recovery from highly undersampled data. Numerical studies demonstrate that this approach can help improve image quality at higher undersampling ratios, enabling real-time cine imaging at higher acceleration rates. In this work, it is shown that these techniques yield a holistic framework for achieving efficient reconstruction of real-time cine images with spatial and temporal resolution sufficient for use in the clinical environment. A thorough description of these techniques from both a theoretical and practical view is provided - both of which may be of interest to the reader in terms of future work.

A comprehensive in vitro study of image accuracy and quality for periodontal diagnosis. Part 1: the influence of X-ray generator on periodontal measurements using conventional and digital receptors.

PubMed

Vandenberghe, Bart; Corpas, Livia; Bosmans, Hilde; Yang, Jie; Jacobs, Reinhilde

2011-08-01

The aim of this study was the determination of image accuracy and quality for periodontal diagnosis using various X-ray generators with conventional and digital radiographs. Thirty-one in vitro periodontal defects were evaluated on intraoral conventional (E-, F/E-speed) and digital images (three indirect, two direct sensors). Standardised radiographs were made with an alternating current (AC), a high-frequency (HF) and a direct current (DC) X-ray unit at rising exposure times (20-160 ms with 20-ms interval) with a constant kV of 70. Three observers assessed bone levels for comparison to the gold standard. Lamina dura, contrast, trabecularisation, crater and furcation involvements were evaluated. Irrespective X-ray generator-type, measurement deviations increased at higher exposure times for solid-state, but decreased for photostimulable storage phosphor (PSP) systems. Accuracy for HF or DC was significantly higher than AC (p < 0.0001), especially at low exposure times. At 0.5- to 1-mm clinical deviation, 27-53% and 32-55% dose savings were demonstrated when using HF or DC generators compared to AC, but only for PSP. No savings were found for solid-state sensors, indicating their higher sensitivity. The use of digital sensors compared to film allowed 15-90% dose savings using the AC tube, whilst solid-state sensors allowed approximately 50% savings compared to PSP, depending on tube type and threshold level.. Accuracy of periodontal diagnosis increases when using HF or DC generators and/or digital receptors with adequate diagnostic information at lower exposure times.

TU-A-18C-01: ACR Accreditation Updates in CT, Ultrasound, Mammography and MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Price, R; Berns, E; Hangiandreou, N

2014-06-15

A goal of an imaging accreditation program is to ensure adequate image quality, verify appropriate staff qualifications, and to assure patient and personnel safety. Currently, more than 35,000 facilities in 10 modalities have been accredited by the American College of Radiology (ACR), making the ACR program one of the most prolific accreditation options in the U.S. In addition, the ACR is one of the accepted accreditations required by some state laws, CMS/MIPPA insurance and others. Familiarity with the ACR accreditation process is therefore essential to clinical diagnostic medical physicists. Maintaining sufficient knowledge of the ACR program must include keeping up-to-datemore » as the various modality requirements are refined to better serve the goals of the program and to accommodate newer technologies and practices. This session consists of presentations from authorities in four ACR accreditation modality programs, including magnetic resonance imaging, mammography, ultrasound, and computed tomography. Each speaker will discuss the general components of the modality program and address any recent changes to the requirements. Learning Objectives: To understand the requirements of the ACR MR accreditation program. The discussion will include accreditation of whole-body general purpose magnets, dedicated extremity systems well as breast MRI accreditation. Anticipated updates to the ACR MRI Quality Control Manual will also be reviewed. To understand the current ACR MAP Accreditation requirement and present the concepts and structure of the forthcoming ACR Digital Mammography QC Manual and Program. To understand the new requirements of the ACR ultrasound accreditation program, and roles the physicist can play in annual equipment surveys and setting up and supervising the routine QC program. To understand the requirements of the ACR CT accreditation program, including updates to the QC manual as well as updates through the FAQ process.« less

MO-AB-207-02: ACR Update in MR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Price, R.

2015-06-15

A goal of an imaging accreditation program is to ensure adequate image quality, verify appropriate staff qualifications, and to assure patient and personnel safety. Currently, more than 35,000 facilities in 10 modalities have been accredited by the American College of Radiology (ACR), making the ACR program one of the most prolific accreditation options in the U.S. In addition, ACR is one of the accepted accreditations required by some state laws, CMS/MIPPA insurance and others. Familiarity with the ACR accreditation process is therefore essential to clinical diagnostic medical physicists. Maintaining sufficient knowledge of the ACR program must include keeping up-to-date asmore » the various modality requirements are refined to better serve the goals of the program and to accommodate newer technologies and practices. This session consists of presentations from authorities in four ACR accreditation modality programs, including magnetic resonance imaging, computed tomography, nuclear medicine, and mammography. Each speaker will discuss the general components of the modality program and address any recent changes to the requirements. Learning Objectives: To understand the requirements of the ACR MR Accreditation program. The discussion will include accreditation of whole-body general purpose magnets, dedicated extremity systems well as breast MRI accreditation. Anticipated updates to the ACR MRI Quality Control Manual will also be reviewed. To understand the requirements of the ACR CT accreditation program, including updates to the QC manual as well as updates through the FAQ process. To understand the requirements of the ACR nuclear medicine accreditation program, and the role of the physicist in annual equipment surveys and the set up and supervision of the routine QC program. To understand the current ACR MAP Accreditation requirement and present the concepts and structure of the forthcoming ACR Digital Mammography QC Manual and Program.« less

MO-AB-207-04: ACR Update in Mammography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berns, E.

2015-06-15

A goal of an imaging accreditation program is to ensure adequate image quality, verify appropriate staff qualifications, and to assure patient and personnel safety. Currently, more than 35,000 facilities in 10 modalities have been accredited by the American College of Radiology (ACR), making the ACR program one of the most prolific accreditation options in the U.S. In addition, ACR is one of the accepted accreditations required by some state laws, CMS/MIPPA insurance and others. Familiarity with the ACR accreditation process is therefore essential to clinical diagnostic medical physicists. Maintaining sufficient knowledge of the ACR program must include keeping up-to-date asmore » the various modality requirements are refined to better serve the goals of the program and to accommodate newer technologies and practices. This session consists of presentations from authorities in four ACR accreditation modality programs, including magnetic resonance imaging, computed tomography, nuclear medicine, and mammography. Each speaker will discuss the general components of the modality program and address any recent changes to the requirements. Learning Objectives: To understand the requirements of the ACR MR Accreditation program. The discussion will include accreditation of whole-body general purpose magnets, dedicated extremity systems well as breast MRI accreditation. Anticipated updates to the ACR MRI Quality Control Manual will also be reviewed. To understand the requirements of the ACR CT accreditation program, including updates to the QC manual as well as updates through the FAQ process. To understand the requirements of the ACR nuclear medicine accreditation program, and the role of the physicist in annual equipment surveys and the set up and supervision of the routine QC program. To understand the current ACR MAP Accreditation requirement and present the concepts and structure of the forthcoming ACR Digital Mammography QC Manual and Program.« less

MO-AB-207-01: ACR Update in CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

McNitt-Gray, M.

2015-06-15

A goal of an imaging accreditation program is to ensure adequate image quality, verify appropriate staff qualifications, and to assure patient and personnel safety. Currently, more than 35,000 facilities in 10 modalities have been accredited by the American College of Radiology (ACR), making the ACR program one of the most prolific accreditation options in the U.S. In addition, ACR is one of the accepted accreditations required by some state laws, CMS/MIPPA insurance and others. Familiarity with the ACR accreditation process is therefore essential to clinical diagnostic medical physicists. Maintaining sufficient knowledge of the ACR program must include keeping up-to-date asmore » the various modality requirements are refined to better serve the goals of the program and to accommodate newer technologies and practices. This session consists of presentations from authorities in four ACR accreditation modality programs, including magnetic resonance imaging, computed tomography, nuclear medicine, and mammography. Each speaker will discuss the general components of the modality program and address any recent changes to the requirements. Learning Objectives: To understand the requirements of the ACR MR Accreditation program. The discussion will include accreditation of whole-body general purpose magnets, dedicated extremity systems well as breast MRI accreditation. Anticipated updates to the ACR MRI Quality Control Manual will also be reviewed. To understand the requirements of the ACR CT accreditation program, including updates to the QC manual as well as updates through the FAQ process. To understand the requirements of the ACR nuclear medicine accreditation program, and the role of the physicist in annual equipment surveys and the set up and supervision of the routine QC program. To understand the current ACR MAP Accreditation requirement and present the concepts and structure of the forthcoming ACR Digital Mammography QC Manual and Program.« less

Value of interactive scanning for improving the outcome of new-learners in transcontinental tele-echocardiography (VISION-in-Tele-Echo) study.

PubMed

Bansal, Manish; Singh, Shaanemeet; Maheshwari, Puneet; Adams, David; McCulloch, Marti L; Dada, Tanuj; Sengupta, Shantanu P; Kasliwal, Ravi R; Pellikka, Patricia A; Sengupta, Partho P

2015-01-01

Point-of-care (POC) echocardiography may be helpful for mass triage, but such a strategy requires adequately trained sonographers at the remote site. The aim of this study was to test the feasibility of using a novel POC echocardiography training program for improving physicians' imaging skills during preanesthetic cardiac evaluations performed in a community camp organized for treating cataract blindness. Seventeen physicians were provided 6 hours of training in the use of POC echocardiography; nine were taught on site and eight were taught online through a transcontinental tele-echocardiography system. The trained physicians subsequently scanned elderly patients undergoing cataract surgery. The quality of images was graded, and agreement between local physicians' interpretations and Web-based interpretations by worldwide experts was compared. A total of 968 studies were performed, with 660 used for validating physicians' competence. Major cardiac abnormalities were seen in 136 patients (14.2%), with 32 (3.3%) deemed prohibitive to surgery in unmonitored settings. Although good-quality images were obtained more frequently by physicians trained on site rather than online (P = .03), there were no differences between the two groups in agreement with expert interpretations. The majority of physicians (70.6%) expressed satisfaction with the training (average Likert-type scale score, 4.24 of 5), with no difference seen between the two groups. The training resulted in significant improvements in self-perceived competence in all components of POC echocardiography (P < .001 for all). This study establishes the feasibility of using short-duration, one-on-one, personalized transcontinental tele-echocardiography education for wider dissemination of echocardiographic skills to local physicians in remote communities, essential for optimizing global cardiovascular health. Copyright © 2015 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

MO-AB-207-00: ACR Update in MR, CT, Nuclear Medicine, and Mammography

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

A goal of an imaging accreditation program is to ensure adequate image quality, verify appropriate staff qualifications, and to assure patient and personnel safety. Currently, more than 35,000 facilities in 10 modalities have been accredited by the American College of Radiology (ACR), making the ACR program one of the most prolific accreditation options in the U.S. In addition, ACR is one of the accepted accreditations required by some state laws, CMS/MIPPA insurance and others. Familiarity with the ACR accreditation process is therefore essential to clinical diagnostic medical physicists. Maintaining sufficient knowledge of the ACR program must include keeping up-to-date asmore » the various modality requirements are refined to better serve the goals of the program and to accommodate newer technologies and practices. This session consists of presentations from authorities in four ACR accreditation modality programs, including magnetic resonance imaging, computed tomography, nuclear medicine, and mammography. Each speaker will discuss the general components of the modality program and address any recent changes to the requirements. Learning Objectives: To understand the requirements of the ACR MR Accreditation program. The discussion will include accreditation of whole-body general purpose magnets, dedicated extremity systems well as breast MRI accreditation. Anticipated updates to the ACR MRI Quality Control Manual will also be reviewed. To understand the requirements of the ACR CT accreditation program, including updates to the QC manual as well as updates through the FAQ process. To understand the requirements of the ACR nuclear medicine accreditation program, and the role of the physicist in annual equipment surveys and the set up and supervision of the routine QC program. To understand the current ACR MAP Accreditation requirement and present the concepts and structure of the forthcoming ACR Digital Mammography QC Manual and Program.« less

MO-AB-207-03: ACR Update in Nuclear Medicine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harkness, B.

A goal of an imaging accreditation program is to ensure adequate image quality, verify appropriate staff qualifications, and to assure patient and personnel safety. Currently, more than 35,000 facilities in 10 modalities have been accredited by the American College of Radiology (ACR), making the ACR program one of the most prolific accreditation options in the U.S. In addition, ACR is one of the accepted accreditations required by some state laws, CMS/MIPPA insurance and others. Familiarity with the ACR accreditation process is therefore essential to clinical diagnostic medical physicists. Maintaining sufficient knowledge of the ACR program must include keeping up-to-date asmore » the various modality requirements are refined to better serve the goals of the program and to accommodate newer technologies and practices. This session consists of presentations from authorities in four ACR accreditation modality programs, including magnetic resonance imaging, computed tomography, nuclear medicine, and mammography. Each speaker will discuss the general components of the modality program and address any recent changes to the requirements. Learning Objectives: To understand the requirements of the ACR MR Accreditation program. The discussion will include accreditation of whole-body general purpose magnets, dedicated extremity systems well as breast MRI accreditation. Anticipated updates to the ACR MRI Quality Control Manual will also be reviewed. To understand the requirements of the ACR CT accreditation program, including updates to the QC manual as well as updates through the FAQ process. To understand the requirements of the ACR nuclear medicine accreditation program, and the role of the physicist in annual equipment surveys and the set up and supervision of the routine QC program. To understand the current ACR MAP Accreditation requirement and present the concepts and structure of the forthcoming ACR Digital Mammography QC Manual and Program.« less

Methods and Reliability of Radiographic Vertebral Fracture Detection in Older Men: The Osteoporotic Fractures in Men Study

PubMed Central

Cawthon, Peggy M.; Haslam, Jane; Fullman, Robin; Peters, Katherine W.; Black, Dennis; Ensrud, Kristine E.; Cummings, Steven R.; Orwoll, Eric S.; Barrett-Connor, Elizabeth; Marshall, Lynn; Steiger, Peter; Schousboe, John T.

2014-01-01

We describe the methods and reliability of radiographic vertebral fracture assessment in MrOS, a cohort of community dwelling men aged ≥65 yrs. Lateral spine radiographs were obtained at Visit 1 (2000-2) and 4.6 years later (Visit 2). Using a workflow tool (SpineAnalyzer™, Optasia Medical), a physician reader completed semi-quantitative (SQ) scoring. Prior to SQ scoring, technicians performed “triage” to reduce physician reader workload, whereby clearly normal spine images were eliminated from SQ scoring with all levels assumed to be SQ=0 (no fracture, “triage negative”); spine images with any possible fracture or abnormality were passed to the physician reader as “triage positive” images. Using a quality assurance sample of images (n=20 participants; 8 with baseline only and 12 with baseline and follow-up images) read multiple times, we calculated intra-reader kappa statistics and percent agreement for SQ scores. A subset of 494 participants' images were read regardless of triage classification to calculate the specificity and sensitivity of triage. Technically adequate images were available for 5958 of 5994 participants at Visit 1, and 4399 of 4423 participants at Visit 2. Triage identified 3215 (53.9%) participants with radiographs that required further evaluation by the physician reader. For prevalent fractures at Visit 1 (SQ≥1), intra-reader kappa statistics ranged from 0.79-0.92; percent agreement ranged from 96.9%-98.9%; sensitivity of the triage was 96.8% and specificity of triage was 46.3%. In conclusion, SQ scoring had excellent intra-rater reliability in our study. The triage process reduces expert reader workload without hindering the ability to identify vertebral fractures. PMID:25003811

Online Kidney Position Verification Using Non-Contrast Radiographs on a Linear Accelerator with on Board KV X-Ray Imaging Capability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willis, David J.; Kron, Tomas; Hubbard, Patricia

2009-01-01

The kidneys are dose-limiting organs in abdominal radiotherapy. Kilovoltage (kV) radiographs can be acquired using on-board imager (OBI)-equipped linear accelerators with better soft tissue contrast and lower radiation doses than conventional portal imaging. A feasibility study was conducted to test the suitability of anterior-posterior (AP) non-contrast kV radiographs acquired at treatment time for online kidney position verification. Anthropomorphic phantoms were used to evaluate image quality and radiation dose. Institutional Review Board approval was given for a pilot study that enrolled 5 adults and 5 children. Customized digitally reconstructed radiographs (DRRs) were generated to provide a priori information on kidney shapemore » and position. Radiotherapy treatment staff performed online evaluation of kidney visibility on OBI radiographs. Kidney dose measured in a pediatric anthropomorphic phantom was 0.1 cGy for kV imaging and 1.7 cGy for MV imaging. Kidneys were rated as well visualized in 60% of patients (90% confidence interval, 34-81%). The likelihood of visualization appears to be influenced by the relative AP separation of the abdomen and kidneys, the axial profile of the kidneys, and their relative contrast with surrounding structures. Online verification of kidney position using AP non-contrast kV radiographs on an OBI-equipped linear accelerator appears feasible for patients with suitable abdominal anatomy. Kidney position information provided is limited to 2-dimensional 'snapshots,' but this is adequate in some clinical situations and potentially advantageous in respiratory-correlated treatments. Successful clinical implementation requires customized partial DRRs, appropriate imaging parameters, and credentialing of treatment staff.« less

Blind image quality assessment without training on human opinion scores

NASA Astrophysics Data System (ADS)

Mittal, Anish; Soundararajan, Rajiv; Muralidhar, Gautam S.; Bovik, Alan C.; Ghosh, Joydeep

2013-03-01

We propose a family of image quality assessment (IQA) models based on natural scene statistics (NSS), that can predict the subjective quality of a distorted image without reference to a corresponding distortionless image, and without any training results on human opinion scores of distorted images. These `completely blind' models compete well with standard non-blind image quality indices in terms of subjective predictive performance when tested on the large publicly available `LIVE' Image Quality database.

21 CFR 900.4 - Standards for accreditation bodies.

Code of Federal Regulations, 2010 CFR

2010-04-01

.... Sufficient breast tissue shall be imaged to ensure that cancers are not likely to be missed because of... potential obscuring effect of overlying breast tissue and motion artifact. (iii) Exposure level. Exposure level shall be adequate to visualize breast structures. Images shall be neither underexposed nor...

JPEG2000 still image coding quality.

PubMed

Chen, Tzong-Jer; Lin, Sheng-Chieh; Lin, You-Chen; Cheng, Ren-Gui; Lin, Li-Hui; Wu, Wei

2013-10-01

This work demonstrates the image qualities between two popular JPEG2000 programs. Two medical image compression algorithms are both coded using JPEG2000, but they are different regarding the interface, convenience, speed of computation, and their characteristic options influenced by the encoder, quantization, tiling, etc. The differences in image quality and compression ratio are also affected by the modality and compression algorithm implementation. Do they provide the same quality? The qualities of compressed medical images from two image compression programs named Apollo and JJ2000 were evaluated extensively using objective metrics. These algorithms were applied to three medical image modalities at various compression ratios ranging from 10:1 to 100:1. Following that, the quality of the reconstructed images was evaluated using five objective metrics. The Spearman rank correlation coefficients were measured under every metric in the two programs. We found that JJ2000 and Apollo exhibited indistinguishable image quality for all images evaluated using the above five metrics (r > 0.98, p < 0.001). It can be concluded that the image quality of the JJ2000 and Apollo algorithms is statistically equivalent for medical image compression.

Environment and quality of life: a reaction from the perspective of social science and environmental design.

PubMed

Grant, L A

1989-11-01

While it is a truism that nursing homes should reflect a homelike setting, relatively few nursing homes have been successful in avoiding a hospital-like image. In this reaction to the paper by Dr. Kayser-Jones, I have reviewed major theoretical models of how environment influences adaptation in the aged and presented some ways in which the nursing home environment can be modified. The delivery of long-term care services to the aged can be improved by addressing their physical, social, and psychological needs through better architectural and interior design, as well as efforts on the part of nursing professionals to ensure adequate patient care. Nurses can play a key role in the design process by assisting architects in programming buildings that meet the basic requirements for good patient care.

76 FR 4579 - Approval and Promulgation of Air Quality Implementation Plan; New Jersey and New York...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-26

... supported by an adequate technical analysis. EPA recommended the various types of information that could be...) must be supported by an adequate technical analysis. In the 2009 Guidance, EPA recommended the various...) because the State did not evaluate or demonstrate with a technical analysis that the emissions reduction...

76 FR 4584 - Approval and Promulgation of Air Quality Implementation Plans; Georgia; Disapproval of Interstate...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-26

... conclusion must be supported by an adequate technical analysis. Second, EPA recommended the various types of... requirement of section 110(a)(2)(D)(i)(I) must be supported by an adequate technical analysis. Additionally... evaluate or demonstrate with a technical analysis that this measure and their intention to rely to the...

Drinking Water Quality in Hospitals and Other Buildings

EPA Science Inventory

Drinking water quality entering large buildings is generally adequately controlled by the water utility, but localized problems may occur within building or “premise” plumbing. Particular concerns are loss of disinfectant residual and temperature variability, which may enhance pa...

7 CFR 305.20 - Treatment requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) Have equipment that is capable of adequately circulating air or water (as relevant to the treatment... must contain requirements for equipment, temperature, water quality, circulation, and other measures... APHIS. The work plan must contain requirements for equipment, temperature, water quality, circulation...

Report: EPA Needs to Fulfill Its Designated Responsibilities to Ensure Effective BioWatch Program

EPA Pesticide Factsheets

Report #2005-P-00012, March 23, 2005. EPA did not provide adequate oversight of the sampling operations to ensure quality assurance guidance was adhered to, potentially affecting the quality of the samples taken.

Real-time measurement of quality during the compaction of subgrade soils.

DOT National Transportation Integrated Search

2012-12-01

Conventional quality control of subgrade soils during their compaction is usually performed by monitoring moisture content and dry density at a few discrete locations. However, randomly selected points do not adequately represent the entire compacted...

A Critical Analysis of the INQAAHE Guidelines of Good Practice for Higher Education Quality Assurance Agencies

ERIC Educational Resources Information Center

Blackmur, Douglas

2008-01-01

The International Network of Quality Assurance Agencies in Higher Education's Guidelines of Good Practice by higher education quality assurance agencies need substantial revision before they can be considered adequate by stakeholders in any national higher education system. Various revisions are proposed in this article. But the International…

Learning Contexts for Young Children in Chile: Process Quality Assessment in Preschool Centres

ERIC Educational Resources Information Center

Herrera, Maria Olivia; Mathiesen, Maria Elena; Merino, Jose Manuel; Recart, Isidora

2005-01-01

ITERS (Infant and Toddler Environment Rating Scale), ECERS (Early Childhood Environment Rating Scale) and SACERS (School Age Care Environment Rating Scale) are used to measure process quality. The psychometric characteristics of the three scales are established, and high reliability and adequate validity are observed. The global quality process…

External Quality Assessment for Zika Virus Molecular Diagnostic Testing, Brazil.

PubMed

Fischer, Carlo; Pedroso, Celia; Mendrone, Alfredo; Bispo de Filippis, Ana Maria; Vallinoto, Antonio Carlos Rosário; Ribeiro, Bergmann Morais; Durigon, Edison Luiz; Marques, Ernesto T A; Campos, Gubio S; Viana, Isabelle F T; Levi, José Eduardo; Scarpelli, Luciano Cesar; Nogueira, Mauricio Lacerda; Bastos, Michele de Souza; Souza, Nathalia C Santiago; Khouri, Ricardo; Lira, Sanny; Komninakis, Shirley Vasconcelos; Baronti, Cécile; Charrel, Rémi N; Kümmerer, Beate M; Drosten, Christian; Brites, Carlos; de Lamballerie, Xavier; Niedrig, Matthias; Netto, Eduardo Martins; Drexler, Jan Felix

2018-05-01

We conducted an external quality assessment of Zika virus molecular diagnostic tests in Brazil using a new Zika virus standard. Of 15 laboratories, 73% showed limited sensitivity and specificity. Viral load estimates varied significantly. Continuous quality assurance is needed to adequately estimate risk for Zika virus-associated disease and determine patient care.

Stress wave sorting of red maple logs for structural quality

Treesearch

Xiping Wang; Robert J. Ross; David W. Green; Brian Brashaw; Karl Englund; Michael Wolcott

2004-01-01

Existing log grading procedures in the United States make only visual assessments of log quality. These procedures do not incorporate estimates of the modulus of elasticity (MOE) of logs. It is questionable whether the visual grading procedures currently used for logs adequately assess the potential quality of structural products manufactured from them, especially...

What Does the Research Tell Us about Teacher Leadership? Research Brief

ERIC Educational Resources Information Center

Center for Comprehensive School Reform and Improvement, 2005

2005-01-01

In this age of high accountability, teacher quality is receiving more attention than ever before. Research that investigates ways to increase teacher quality is much needed, making this study a timely addition to the literature. Although increases in student achievement related to teacher quality have yet to be adequately documented, the research…

Quality Support Infrastructure in Early Childhood: Still (Mostly) Missing

ERIC Educational Resources Information Center

Azzi-Lessing, Lenette

2009-01-01

Support for early care and education among policy makers and the public is at an unprecedented high. As investments in early care and education programs in the United States continue to rise, the issue of quality becomes increasingly critical. This article addresses the need for adequate infrastructure to support high-quality early care and…

76 FR 16358 - Approval and Promulgation of Air Quality Implementation Plans; Connecticut, Maine, New Hampshire...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-23

... Protection, State Office Building, 79 Elm Street, Hartford, CT 06106- 1630; the Bureau of Air Quality Control... evaluation of the States' submittals? A. Emission Limits and Other Control Measures B. Ambient Air Quality Monitoring/Data System C. Program for Enforcement of Control Measures D. Interstate Transport E. Adequate...

Blind image quality assessment based on aesthetic and statistical quality-aware features

NASA Astrophysics Data System (ADS)

Jenadeleh, Mohsen; Masaeli, Mohammad Masood; Moghaddam, Mohsen Ebrahimi

2017-07-01

The main goal of image quality assessment (IQA) methods is the emulation of human perceptual image quality judgments. Therefore, the correlation between objective scores of these methods with human perceptual scores is considered as their performance metric. Human judgment of the image quality implicitly includes many factors when assessing perceptual image qualities such as aesthetics, semantics, context, and various types of visual distortions. The main idea of this paper is to use a host of features that are commonly employed in image aesthetics assessment in order to improve blind image quality assessment (BIQA) methods accuracy. We propose an approach that enriches the features of BIQA methods by integrating a host of aesthetics image features with the features of natural image statistics derived from multiple domains. The proposed features have been used for augmenting five different state-of-the-art BIQA methods, which use statistical natural scene statistics features. Experiments were performed on seven benchmark image quality databases. The experimental results showed significant improvement of the accuracy of the methods.

SU-E-I-95: Personalized Radiography Technical Parameters for Each Patient and Exam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soares, F; Camozzato, T; Kahl, G

Purpose: To determine exact electrical parameters (kV, mAs) a radiological technologist shall use taking account the exam and patient's structure, with guarantee of minimum dose and adequate quality image. Methods: A patient's absorbed dose equation was developed by means of Entrance Skin Dose (ESD), irradiated area and patient width for specific anatomy. ESD is calculated from a developed equation, where entrance surface air-KERMA and backscatter factor are included, with air-to-skin coefficient conversion. We developed specific Lambert-Beer attenuation equations derived from mass energy-absorption coefficients data for skin, fat, and muscle and bone as one tissue. Anatomy tissue thickness distribution at centralmore » X-ray location in anteroposterior incidence for hand and chest, was estimate by discounting constant skin and bone thickness from patient measured width, assuming the result as muscle and fat. A clinical research at a big hospital were executed when real parameters (kV, mAs, filtration, ripple) used by technologists were combined with the image quality and patient's data: anatomy width, height and weight. A correlation among the best images acquired and electrical parameters used were confronted with patient's data and dose estimation. The best combinations were used as gold standards. Results: For each anatomy, two equations were developed to calculate voltage (kV) and exposure (mAs) to reproduce and interpolate the gold standards. Patient is measured and data are input into equations, giving radiological technologists the right set of electrical parameters for that specific exam. Conclusion: This work indicates that radiological technologist can personalize the exact electrical parameters for each patient exam, instead of using standard values. It also guarantee that patients under or over-sized measures will receive the right dose for the best image. It will stop wrong empiric adjusts technologists do when examining a non-standard patient and reduce probability of radiography retaken because of over or under exposition.« less

Evaluation of image quality of digital photo documentation of female genital injuries following sexual assault.

PubMed

Ernst, E J; Speck, Patricia M; Fitzpatrick, Joyce J

2011-12-01

With the patient's consent, physical injuries sustained in a sexual assault are evaluated and treated by the sexual assault nurse examiner (SANE) and documented on preprinted traumagrams and with photographs. Digital imaging is now available to the SANE for documentation of sexual assault injuries, but studies of the image quality of forensic digital imaging of female genital injuries after sexual assault were not found in the literature. The Photo Documentation Image Quality Scoring System (PDIQSS) was developed to rate the image quality of digital photo documentation of female genital injuries after sexual assault. Three expert observers performed evaluations on 30 separate images at two points in time. An image quality score, the sum of eight integral technical and anatomical attributes on the PDIQSS, was obtained for each image. Individual image quality ratings, defined by rating image quality for each of the data, were also determined. The results demonstrated a high level of image quality and agreement when measured in all dimensions. For the SANE in clinical practice, the results of this study indicate that a high degree of agreement exists between expert observers when using the PDIQSS to rate image quality of individual digital photographs of female genital injuries after sexual assault. © 2011 International Association of Forensic Nurses.

[Feasibility and results of the short Diet Quality Screener in Primary Care: EMAP study].

PubMed

Ríos-Rodríguez, María de Los Ángeles; García-Cerdán, María Rosa; Calonge-Vallejo, Ana Rosa; Tobella-Andreu, Laia; Baena-Díez, José Miguel; Schröder, Helmut

To study the feasibility and results of the self-reported short diet quality screener (sDQS) in Primary Care. The variables associated with difficulty and inadequate diet are also determined. Cross-sectional descriptive study conducted with 196 participants aged >18 years with diabetes mellitus, hypertension, or hypercholesterolaemia, consecutively included from 4 Primary Health Care Centres in Barcelona. The main variables collected were, age, sex, educational level, cardiovascular risk factors, body mass index, time to complete the sDQS, degree of difficulty, and diet score: inadequate diet ≤18, adequate in some aspects 19-27, adequate >27. The mean age was 48.8 years (52% males). The analysis of the variables showed that the prevalence of having higher than a primary education level, hypertension, diabetes, hypercholesterolemia, and obesity was 50%, 54.6%, 23.5%, 56.6%, and 27.5%, respectively. The mean time to complete the questionnaire was 2.3min. More than 80% considered it easy or very easy. An inadequate diet was reported by 21.4%, adequate in some aspects by 76.5%, and an adequate diet only by 2%. To be older than 49 years and a low diet quality increased the risk of needing ≥2min to complete the sDQS (OR 2.0, 95% CI; 1.0-4.3, and OR 2.3, 95% CI; 1.1-5.1, respectively). Not following a low cholesterol diet and age less than 49 years increased the risk of a low diet quality (OR 2.2; 95% CI: 1.1-4.5, and OR 2.9; 95% CI: 1.2-6.8, respectively). The completion of the sDQS is easy and was not a significant time-burden in Primary Care. A significant proportion of participants with cardiovascular risk reported a low diet quality. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

Development and testing of LANDSAT-assisted procedures for cost-effective forest management

NASA Technical Reports Server (NTRS)

Colwell, J. E.; Sanders, P. A.; Thomson, F. J.

1982-01-01

The capability of LANDSAT data to make certain forest management activities on the Clearwater National Forest in Idaho more efficient and/or more effective was examined. One task was designed to evaluate the utility of single-date categorized LANDSAT data as a source of land cover information for use in assessing elk habitat quality. LANDSAT data was used to categorize conifer forest on the basis of the percentage crown closure. This information was used to evaluate elk habitat quality on the basis of the ratio of cover to forage. A preliminary conclusion is that categorized LANDSAT data can be helpful for assessing current elk habitat quality if the relationships between crown closure and hiding cover can be adequately defined. Another task was designed to evaluate the utility of merged two-date LANDSAT data for updating the existing (1972) Clearwater Forest land cover information. LANDSAT data from 1972 and 1981 were merged, and change images were created. These products indicated where major changes were taking place. These areas could then be examined on aerial photography or in the field to further characterize the nature and magnitude of the change. The 1972 land cover information could be subsequently altered in these changed areas, whereas areas with no change would not have to be re-examined.

Ethical dilemmas of recording and reviewing neonatal resuscitation.

PubMed

den Boer, Maria C; Houtlosser, Mirjam; van Zanten, Henriëtte Anje; Foglia, Elizabeth E; Engberts, Dirk P; Te Pas, Arjan B

2018-05-01

Neonatal resuscitation is provided to approximately 3% of neonates. Adequate ventilation is often the key to successful resuscitation, but this can be difficult to provide. There is increasing evidence that inappropriate respiratory support can have severe consequences. Several neonatal intensive care units have recorded and reviewed neonatal resuscitation procedures for quality assessment, education and research; however, ethical dilemmas sometimes make it difficult to implement this review process. We reviewed the literature on the development of recording and reviewing neonatal resuscitation and have summarised the ethical concerns involved. Recording and reviewing vital physiological parameters and video imaging of neonatal resuscitation in the delivery room is a valuable tool for quality assurance, education and research. Furthermore, it can improve the quality of neonatal resuscitation provided. We observed that ethical dilemmas arise as the review process is operating in several domains of healthcare that all have their specific moral framework with requirements and conditions on issues such as consent, privacy and data storage. These moral requirements and conditions vary due to local circumstances. Further research on the ethical aspects of recording and reviewing is desirable before wider implementation of this technique can be recommended. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Image aesthetic quality evaluation using convolution neural network embedded learning

NASA Astrophysics Data System (ADS)

Li, Yu-xin; Pu, Yuan-yuan; Xu, Dan; Qian, Wen-hua; Wang, Li-peng

2017-11-01

A way of embedded learning convolution neural network (ELCNN) based on the image content is proposed to evaluate the image aesthetic quality in this paper. Our approach can not only solve the problem of small-scale data but also score the image aesthetic quality. First, we chose Alexnet and VGG_S to compare for confirming which is more suitable for this image aesthetic quality evaluation task. Second, to further boost the image aesthetic quality classification performance, we employ the image content to train aesthetic quality classification models. But the training samples become smaller and only using once fine-tuning cannot make full use of the small-scale data set. Third, to solve the problem in second step, a way of using twice fine-tuning continually based on the aesthetic quality label and content label respective is proposed, the classification probability of the trained CNN models is used to evaluate the image aesthetic quality. The experiments are carried on the small-scale data set of Photo Quality. The experiment results show that the classification accuracy rates of our approach are higher than the existing image aesthetic quality evaluation approaches.

Digital radiography: optimization of image quality and dose using multi-frequency software.

PubMed

Precht, H; Gerke, O; Rosendahl, K; Tingberg, A; Waaler, D

2012-09-01

New developments in processing of digital radiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults. To examine whether the use of MFP software reduces the radiation dose without compromising quality at DR of the femur in 5-year-old-equivalent anthropomorphic and technical phantoms. A total of 110 images of an anthropomorphic phantom were imaged on a DR system (Canon DR with CXDI-50 C detector and MLT[S] software) and analyzed by three pediatric radiologists using Visual Grading Analysis. In addition, 3,500 images taken of a technical contrast-detail phantom (CDRAD 2.0) provide an objective image-quality assessment. Optimal image-quality was maintained at a dose reduction of 61% with MLT(S) optimized images. Even for images of diagnostic quality, MLT(S) provided a dose reduction of 88% as compared to the reference image. Software impact on image quality was found significant for dose (mAs), dynamic range dark region and frequency band. By optimizing image processing parameters, a significant dose reduction is possible without significant loss of image quality.

Correlation of the clinical and physical image quality in chest radiography for average adults with a computed radiography imaging system.

PubMed

Moore, C S; Wood, T J; Beavis, A W; Saunderson, J R

2013-07-01

The purpose of this study was to examine the correlation between the quality of visually graded patient (clinical) chest images and a quantitative assessment of chest phantom (physical) images acquired with a computed radiography (CR) imaging system. The results of a previously published study, in which four experienced image evaluators graded computer-simulated postero-anterior chest images using a visual grading analysis scoring (VGAS) scheme, were used for the clinical image quality measurement. Contrast-to-noise ratio (CNR) and effective dose efficiency (eDE) were used as physical image quality metrics measured in a uniform chest phantom. Although optimal values of these physical metrics for chest radiography were not derived in this work, their correlation with VGAS in images acquired without an antiscatter grid across the diagnostic range of X-ray tube voltages was determined using Pearson's correlation coefficient. Clinical and physical image quality metrics increased with decreasing tube voltage. Statistically significant correlations between VGAS and CNR (R=0.87, p<0.033) and eDE (R=0.77, p<0.008) were observed. Medical physics experts may use the physical image quality metrics described here in quality assurance programmes and optimisation studies with a degree of confidence that they reflect the clinical image quality in chest CR images acquired without an antiscatter grid. A statistically significant correlation has been found between the clinical and physical image quality in CR chest imaging. The results support the value of using CNR and eDE in the evaluation of quality in clinical thorax radiography.

Process perspective on image quality evaluation

NASA Astrophysics Data System (ADS)

Leisti, Tuomas; Halonen, Raisa; Kokkonen, Anna; Weckman, Hanna; Mettänen, Marja; Lensu, Lasse; Ritala, Risto; Oittinen, Pirkko; Nyman, Göte

2008-01-01

The psychological complexity of multivariate image quality evaluation makes it difficult to develop general image quality metrics. Quality evaluation includes several mental processes and ignoring these processes and the use of a few test images can lead to biased results. By using a qualitative/quantitative (Interpretation Based Quality, IBQ) methodology, we examined the process of pair-wise comparison in a setting, where the quality of the images printed by laser printer on different paper grades was evaluated. Test image consisted of a picture of a table covered with several objects. Three other images were also used, photographs of a woman, cityscape and countryside. In addition to the pair-wise comparisons, observers (N=10) were interviewed about the subjective quality attributes they used in making their quality decisions. An examination of the individual pair-wise comparisons revealed serious inconsistencies in observers' evaluations on the test image content, but not on other contexts. The qualitative analysis showed that this inconsistency was due to the observers' focus of attention. The lack of easily recognizable context in the test image may have contributed to this inconsistency. To obtain reliable knowledge of the effect of image context or attention on subjective image quality, a qualitative methodology is needed.

Digital Image Restoration Under a Regression Model - The Unconstrained, Linear Equality and Inequality Constrained Approaches

DTIC Science & Technology

1974-01-01

REGRESSION MODEL - THE UNCONSTRAINED, LINEAR EQUALITY AND INEQUALITY CONSTRAINED APPROACHES January 1974 Nelson Delfino d’Avila Mascarenha;? Image...Report 520 DIGITAL IMAGE RESTORATION UNDER A REGRESSION MODEL THE UNCONSTRAINED, LINEAR EQUALITY AND INEQUALITY CONSTRAINED APPROACHES January...a two- dimensional form adequately describes the linear model . A dis- cretization is performed by using quadrature methods. By trans

Image Quality Assessment of High-Resolution Satellite Images with Mtf-Based Fuzzy Comprehensive Evaluation Method

NASA Astrophysics Data System (ADS)

Wu, Z.; Luo, Z.; Zhang, Y.; Guo, F.; He, L.

2018-04-01

A Modulation Transfer Function (MTF)-based fuzzy comprehensive evaluation method was proposed in this paper for the purpose of evaluating high-resolution satellite image quality. To establish the factor set, two MTF features and seven radiant features were extracted from the knife-edge region of image patch, which included Nyquist, MTF0.5, entropy, peak signal to noise ratio (PSNR), average difference, edge intensity, average gradient, contrast and ground spatial distance (GSD). After analyzing the statistical distribution of above features, a fuzzy evaluation threshold table and fuzzy evaluation membership functions was established. The experiments for comprehensive quality assessment of different natural and artificial objects was done with GF2 image patches. The results showed that the calibration field image has the highest quality scores. The water image has closest image quality to the calibration field, quality of building image is a little poor than water image, but much higher than farmland image. In order to test the influence of different features on quality evaluation, the experiment with different weights were tested on GF2 and SPOT7 images. The results showed that different weights correspond different evaluating effectiveness. In the case of setting up the weights of edge features and GSD, the image quality of GF2 is better than SPOT7. However, when setting MTF and PSNR as main factor, the image quality of SPOT7 is better than GF2.

Digitized hand-wrist radiographs: comparison of subjective and software-derived image quality at various compression ratios.

PubMed

McCord, Layne K; Scarfe, William C; Naylor, Rachel H; Scheetz, James P; Silveira, Anibal; Gillespie, Kevin R

2007-05-01

The objectives of this study were to compare the effect of JPEG 2000 compression of hand-wrist radiographs on observer image quality qualitative assessment and to compare with a software-derived quantitative image quality index. Fifteen hand-wrist radiographs were digitized and saved as TIFF and JPEG 2000 images at 4 levels of compression (20:1, 40:1, 60:1, and 80:1). The images, including rereads, were viewed by 13 orthodontic residents who determined the image quality rating on a scale of 1 to 5. A quantitative analysis was also performed by using a readily available software based on the human visual system (Image Quality Measure Computer Program, version 6.2, Mitre, Bedford, Mass). ANOVA was used to determine the optimal compression level (P < or =.05). When we compared subjective indexes, JPEG compression greater than 60:1 significantly reduced image quality. When we used quantitative indexes, the JPEG 2000 images had lower quality at all compression ratios compared with the original TIFF images. There was excellent correlation (R2 >0.92) between qualitative and quantitative indexes. Image Quality Measure indexes are more sensitive than subjective image quality assessments in quantifying image degradation with compression. There is potential for this software-based quantitative method in determining the optimal compression ratio for any image without the use of subjective raters.

Image quality scaling of electrophotographic prints

NASA Astrophysics Data System (ADS)

Johnson, Garrett M.; Patil, Rohit A.; Montag, Ethan D.; Fairchild, Mark D.

2003-12-01

Two psychophysical experiments were performed scaling overall image quality of black-and-white electrophotographic (EP) images. Six different printers were used to generate the images. There were six different scenes included in the experiment, representing photographs, business graphics, and test-targets. The two experiments were split into a paired-comparison experiment examining overall image quality, and a triad experiment judging overall similarity and dissimilarity of the printed images. The paired-comparison experiment was analyzed using Thurstone's Law, to generate an interval scale of quality, and with dual scaling, to determine the independent dimensions used for categorical scaling. The triad experiment was analyzed using multidimensional scaling to generate a psychological stimulus space. The psychophysical results indicated that the image quality was judged mainly along one dimension and that the relationships among the images can be described with a single dimension in most cases. Regression of various physical measurements of the images to the paired comparison results showed that a small number of physical attributes of the images could be correlated with the psychophysical scale of image quality. However, global image difference metrics did not correlate well with image quality.

Digital Longitudinal Tomosynthesis

NASA Astrophysics Data System (ADS)

Rimkus, Daniel Steven

1985-12-01

The purpose of this dissertation was to investigate the clinical utility of digital longitudinal tomosynthesis in radiology. By acquiring a finite group of digital images during a longitudinal tomographic exposure, and processing these images, tomographic planes, other than the fulcrum plane, can be reconstructed. This process is now termed "tomosynthesis". A prototype system utilizing this technique was developed. Both phantom and patient studies were done with this system. The phantom studies were evaluated by subjective, visual criterion and by quantitative analysis of edge sharpness and noise in the reconstructions. Two groups of patients and one volunteer were studied. The first patient group consisted of 8 patients undergoing intravenous urography (IVU). These patients had digital tomography and film tomography of the abdomen. The second patient group consisted of 4 patients with lung cancer admitted to the hospital for laser resection of endobronchial tumor. These patients had mediastinal digital tomograms to evaluate the trachea and mainstem bronchi. The knee of one volunteer was imaged by film tomography and digital tomography. The results of the phantom studies showed that the digital reconstructions accurately produced images of the desired planes. The edge sharpness of the reconstructions approached that of the acquired images. Adequate reconstructions were achieved with as few as 5 images acquired during the exposure, with the quality of the reconstructions improving as the number of images acquired increased. The IVU patients' digital studies had less contrast and spatial resolution than the film tomograms. The single renal lesion visible on the film tomograms was also visible in the digital images. The digital mediastinal studies were felt by several radiologists to be superior to a standard chest xray in evaluating the airways. The digital images of the volunteer's knee showed many of the same anatomic features as the film tomogram, but the digital images had less spatial and contrast resolution. With the equipment improvements discussed in the thesis, digital tomography may have an important role in radiology.

Integration of radiographic images with an electronic medical record.

PubMed Central

Overhage, J. M.; Aisen, A.; Barnes, M.; Tucker, M.; McDonald, C. J.

2001-01-01

Radiographic images are important and expensive diagnostic tests. However, the provider caring for the patient often does not review the images directly due to time constraints. Institutions can use picture archiving and communications systems to make images more available to the provider, but this may not be the best solution. We integrated radiographic image review into the Regenstrief Medical Record System in order to address this problem. To achieve adequate performance, we store JPEG compressed images directly in the RMRS. Currently, physicians review about 5% of all radiographic studies using the RMRS image review function. PMID:11825241

Automated daily quality control analysis for mammography in a multi-unit imaging center.

PubMed

Sundell, Veli-Matti; Mäkelä, Teemu; Meaney, Alexander; Kaasalainen, Touko; Savolainen, Sauli

2018-01-01

Background The high requirements for mammography image quality necessitate a systematic quality assurance process. Digital imaging allows automation of the image quality analysis, which can potentially improve repeatability and objectivity compared to a visual evaluation made by the users. Purpose To develop an automatic image quality analysis software for daily mammography quality control in a multi-unit imaging center. Material and Methods An automated image quality analysis software using the discrete wavelet transform and multiresolution analysis was developed for the American College of Radiology accreditation phantom. The software was validated by analyzing 60 randomly selected phantom images from six mammography systems and 20 phantom images with different dose levels from one mammography system. The results were compared to a visual analysis made by four reviewers. Additionally, long-term image quality trends of a full-field digital mammography system and a computed radiography mammography system were investigated. Results The automated software produced feature detection levels comparable to visual analysis. The agreement was good in the case of fibers, while the software detected somewhat more microcalcifications and characteristic masses. Long-term follow-up via a quality assurance web portal demonstrated the feasibility of using the software for monitoring the performance of mammography systems in a multi-unit imaging center. Conclusion Automated image quality analysis enables monitoring the performance of digital mammography systems in an efficient, centralized manner.

Effect of ISDN bandwidth on image quality for telemedicine transmission of obstetric ultrasonography.

PubMed

Malone, F D; Athanassiou, A; Nores, J; D'Alton, M E

1998-01-01

To evaluate objectively the effect of different bandwidths on the ability to interpret obstetric ultrasound scans transmitted live over a commercial telephone network. An integrated services digital network (ISDN) was established from three satellite offices to our central prenatal diagnostic center. In the first half of the study, the network was based on four ISDN channels transmitting at a bandwidth of 256 kbits per second (kbps), while in the second half of the study, this was increased to six ISDN channels transmitting at 384 kbps. A physician trained in obstetric ultrasonography provided an interpretation of fetal anatomy using a live, real-time telemedicine link. A scoring system consisting of 33 anatomic items was used to evaluate image quality objectively. The number of transmissions complicated by motion artifact was also recorded. One hundred patients had a fetal anatomy survey performed using the 256 kbps system, and these interpretations were compared with those from another group of 100 patients who were examined using the 384 kbps system. Although the visibility of the 33 anatomic items was similar using the two systems, significantly more examinations at 256 kbps were complicated by motion artifact (12% vs. 3%; P = 0.02). Remote sonographic viewing of fetal anatomy was adequate using both 256 and 384 kbps systems, although motion artifact was significantly more likely to occur using the slower system. This problem may affect the ability of the lower-bandwidth system to allow optimal detection when fetal anomalies are present.

Assessing product image quality for online shopping

NASA Astrophysics Data System (ADS)

Goswami, Anjan; Chung, Sung H.; Chittar, Naren; Islam, Atiq

2012-01-01

Assessing product-image quality is important in the context of online shopping. A high quality image that conveys more information about a product can boost the buyer's confidence and can get more attention. However, the notion of image quality for product-images is not the same as that in other domains. The perception of quality of product-images depends not only on various photographic quality features but also on various high level features such as clarity of the foreground or goodness of the background etc. In this paper, we define a notion of product-image quality based on various such features. We conduct a crowd-sourced experiment to collect user judgments on thousands of eBay's images. We formulate a multi-class classification problem for modeling image quality by classifying images into good, fair and poor quality based on the guided perceptual notions from the judges. We also conduct experiments with regression using average crowd-sourced human judgments as target. We compute a pseudo-regression score with expected average of predicted classes and also compute a score from the regression technique. We design many experiments with various sampling and voting schemes with crowd-sourced data and construct various experimental image quality models. Most of our models have reasonable accuracies (greater or equal to 70%) on test data set. We observe that our computed image quality score has a high (0.66) rank correlation with average votes from the crowd sourced human judgments.

Accuracy of the Canadian C-spine rule and NEXUS to screen for clinically important cervical spine injury in patients following blunt trauma: a systematic review

PubMed Central

Michaleff, Zoe A.; Maher, Chris G.; Verhagen, Arianne P.; Rebbeck, Trudy; Lin, Chung-Wei Christine

2012-01-01

Background: There is uncertainty about the optimal approach to screen for clinically important cervical spine (C-spine) injury following blunt trauma. We conducted a systematic review to investigate the diagnostic accuracy of the Canadian C-spine rule and the National Emergency X-Radiography Utilization Study (NEXUS) criteria, 2 rules that are available to assist emergency physicians to assess the need for cervical spine imaging. Methods: We identified studies by an electronic search of CINAHL, Embase and MEDLINE. We included articles that reported on a cohort of patients who experienced blunt trauma and for whom clinically important cervical spine injury detectable by diagnostic imaging was the differential diagnosis; evaluated the diagnostic accuracy of the Canadian C-spine rule or NEXUS or both; and used an adequate reference standard. We assessed the methodologic quality using the Quality Assessment of Diagnostic Accuracy Studies criteria. We used the extracted data to calculate sensitivity, specificity, likelihood ratios and post-test probabilities. Results: We included 15 studies of modest methodologic quality. For the Canadian C-spine rule, sensitivity ranged from 0.90 to 1.00 and specificity ranged from 0.01 to 0.77. For NEXUS, sensitivity ranged from 0.83 to 1.00 and specificity ranged from 0.02 to 0.46. One study directly compared the accuracy of these 2 rules using the same cohort and found that the Canadian C-spine rule had better accuracy. For both rules, a negative test was more informative for reducing the probability of a clinically important cervical spine injury. Interpretation: Based on studies with modest methodologic quality and only one direct comparison, we found that the Canadian C-spine rule appears to have better diagnostic accuracy than the NEXUS criteria. Future studies need to follow rigorous methodologic procedures to ensure that the findings are as free of bias as possible. PMID:23048086

Comparative Analysis of Reconstructed Image Quality in a Simulated Chromotomographic Imager

DTIC Science & Technology

2014-03-01

quality . This example uses five basic images a backlit bar chart with random intensity, 100 nm separation. A total of 54 initial target...compared for a variety of scenes. Reconstructed image quality is highly dependent on the initial target hypercube so a total of 54 initial target...COMPARATIVE ANALYSIS OF RECONSTRUCTED IMAGE QUALITY IN A SIMULATED CHROMOTOMOGRAPHIC IMAGER THESIS

Quality Management and Calibration

NASA Astrophysics Data System (ADS)

Merkus, Henk G.

Good specification of a product’s performance requires adequate characterization of relevant properties. Particulate products are usually characterized by some PSD, shape or porosity parameter(s). For proper characterization, adequate sampling, dispersion, and measurement procedures should be available or developed and skilful personnel should use appropriate, well-calibrated/qualified equipment. The characterization should be executed, in agreement with customers, in a wellorganized laboratory. All related aspects should be laid down in a quality handbook. The laboratory should provide proof for its capability to perform the characterization of stated products and/or reference materials within stated confidence limits. This can be done either by internal validation and audits or by external GLP accreditation.

Possible environmental effects of increased coal use in California

NASA Technical Reports Server (NTRS)

Carey, D. L.

1978-01-01

If coal is to be utilized in California it must be made compatible with the state's drive toward restoring environmental quality. The impacts resulting from coal's mining and transportation, or from water consumption, water quality degradation and electric transmission line routing can probably be adequately mitigated through strong and early planning efforts, the use of improved control and process technologies, and sincere utility commitment. The socioeconomic impacts may prove somewhat more difficult to satisfactorily mitigate. Of greatest concern is adequate control of generated air pollutants and disposal of solid and liquid wastes since acceptable technologies or handling techniques have yet to be conclusively demonstrated.

The politics of assessment: water and sanitation MDGs in the Middle East.

PubMed

Zawahri, Neda; Sowers, Jeannie; Weinthal, Erika

2011-01-01

The Middle East and North Africa (MENA) is generally considered to be making adequate progress towards meeting Target 10 of the Millennium Development Goals (MDGs), which calls for halving the proportion of the population with inadequate access to drinking water and sanitation. Progress towards achieving Target 10 is evaluated by the Joint Monitoring Programme (JMP), run by UNICEF and WHO. This article shows that the assessment methodologies employed by the JMP significantly overstate coverage rates in the drinking water and sanitation sectors, by overlooking and ‘not counting’ problems of access, affordability, quality of service and pollution. The authors show that states in MENA often fail to provide safe drinking water and adequate sanitation services, particularly in densely populated informal settlements, and that many centralized water and sanitation infrastructures contribute to water pollution and contamination. Despite the glaring gap between the MDG statistics and the evidence available from national and local reports, exclusionary political regimes in the region have had few incentives to adopt more accurate assessments and improve the quality of service. While international organizations have proposed some reforms, they too lack incentives to employ adequate measures that gauge access, quality and affordability of drinking water and sanitation services.

Retinal Image Quality Assessment for Spaceflight-Induced Vision Impairment Study

NASA Technical Reports Server (NTRS)

Vu, Amanda Cadao; Raghunandan, Sneha; Vyas, Ruchi; Radhakrishnan, Krishnan; Taibbi, Giovanni; Vizzeri, Gianmarco; Grant, Maria; Chalam, Kakarla; Parsons-Wingerter, Patricia

2015-01-01

Long-term exposure to space microgravity poses significant risks for visual impairment. Evidence suggests such vision changes are linked to cephalad fluid shifts, prompting a need to directly quantify microgravity-induced retinal vascular changes. The quality of retinal images used for such vascular remodeling analysis, however, is dependent on imaging methodology. For our exploratory study, we hypothesized that retinal images captured using fluorescein imaging methodologies would be of higher quality in comparison to images captured without fluorescein. A semi-automated image quality assessment was developed using Vessel Generation Analysis (VESGEN) software and MATLAB® image analysis toolboxes. An analysis of ten images found that the fluorescein imaging modality provided a 36% increase in overall image quality (two-tailed p=0.089) in comparison to nonfluorescein imaging techniques.

Can image enhancement allow radiation dose to be reduced whilst maintaining the perceived diagnostic image quality required for coronary angiography?

PubMed Central

Joshi, Anuja; Gislason-Lee, Amber J; Keeble, Claire; Sivananthan, Uduvil M

2017-01-01

Objective: The aim of this research was to quantify the reduction in radiation dose facilitated by image processing alone for percutaneous coronary intervention (PCI) patient angiograms, without reducing the perceived image quality required to confidently make a diagnosis. Methods: Incremental amounts of image noise were added to five PCI angiograms, simulating the angiogram as having been acquired at corresponding lower dose levels (10–89% dose reduction). 16 observers with relevant experience scored the image quality of these angiograms in 3 states—with no image processing and with 2 different modern image processing algorithms applied. These algorithms are used on state-of-the-art and previous generation cardiac interventional X-ray systems. Ordinal regression allowing for random effects and the delta method were used to quantify the dose reduction possible by the processing algorithms, for equivalent image quality scores. Results: Observers rated the quality of the images processed with the state-of-the-art and previous generation image processing with a 24.9% and 15.6% dose reduction, respectively, as equivalent in quality to the unenhanced images. The dose reduction facilitated by the state-of-the-art image processing relative to previous generation processing was 10.3%. Conclusion: Results demonstrate that statistically significant dose reduction can be facilitated with no loss in perceived image quality using modern image enhancement; the most recent processing algorithm was more effective in preserving image quality at lower doses. Advances in knowledge: Image enhancement was shown to maintain perceived image quality in coronary angiography at a reduced level of radiation dose using computer software to produce synthetic images from real angiograms simulating a reduction in dose. PMID:28124572

The influence of body mass index, age, implants, and dental restorations on image quality of cone beam computed tomography.

PubMed

Ritter, Lutz; Mischkowski, Robert A; Neugebauer, Jörg; Dreiseidler, Timo; Scheer, Martin; Keeve, Erwin; Zöller, Joachim E

2009-09-01

The aim was to determine the influence of patient age, gender, body mass index (BMI), amount of dental restorations, and implants on image quality of cone-beam computerized tomography (CBCT). Fifty CBCT scans of a preretail version of Galileos (Sirona, Germany) were investigated retrospectively by 4 observers regarding image quality of 6 anatomic structures, pathologic findings detection, subjective exposure quality, and artifacts. Patient age, BMI, gender, amount of dental restorations, and implants were recorded and statistically tested for correlations to image quality. A negative effect on image quality was found statistically significantly correlated with age and the amount of dental restorations. None of the investigated image features were garbled by any of the investigated influence factors. Age and the amount of dental restorations appear to have a negative impact on CBCT image quality, whereas gender and BMI do not. Image quality of mental foramen, mandibular canal, and nasal floor are affected negatively by age but not by the amount of dental restorations. Further studies are required to elucidate influence factors on CBCT image quality.

Correlation of the clinical and physical image quality in chest radiography for average adults with a computed radiography imaging system

PubMed Central

Wood, T J; Beavis, A W; Saunderson, J R

2013-01-01

Objective: The purpose of this study was to examine the correlation between the quality of visually graded patient (clinical) chest images and a quantitative assessment of chest phantom (physical) images acquired with a computed radiography (CR) imaging system. Methods: The results of a previously published study, in which four experienced image evaluators graded computer-simulated postero-anterior chest images using a visual grading analysis scoring (VGAS) scheme, were used for the clinical image quality measurement. Contrast-to-noise ratio (CNR) and effective dose efficiency (eDE) were used as physical image quality metrics measured in a uniform chest phantom. Although optimal values of these physical metrics for chest radiography were not derived in this work, their correlation with VGAS in images acquired without an antiscatter grid across the diagnostic range of X-ray tube voltages was determined using Pearson’s correlation coefficient. Results: Clinical and physical image quality metrics increased with decreasing tube voltage. Statistically significant correlations between VGAS and CNR (R=0.87, p<0.033) and eDE (R=0.77, p<0.008) were observed. Conclusion: Medical physics experts may use the physical image quality metrics described here in quality assurance programmes and optimisation studies with a degree of confidence that they reflect the clinical image quality in chest CR images acquired without an antiscatter grid. Advances in knowledge: A statistically significant correlation has been found between the clinical and physical image quality in CR chest imaging. The results support the value of using CNR and eDE in the evaluation of quality in clinical thorax radiography. PMID:23568362

On pictures and stuff: image quality and material appearance

NASA Astrophysics Data System (ADS)

Ferwerda, James A.

2014-02-01

Realistic images are a puzzle because they serve as visual representations of objects while also being objects themselves. When we look at an image we are able to perceive both the properties of the image and the properties of the objects represented by the image. Research on image quality has typically focused improving image properties (resolution, dynamic range, frame rate, etc.) while ignoring the issue of whether images are serving their role as visual representations. In this paper we describe a series of experiments that investigate how well images of different quality convey information about the properties of the objects they represent. In the experiments we focus on the effects that two image properties (contrast and sharpness) have on the ability of images to represent the gloss of depicted objects. We found that different experimental methods produced differing results. Specifically, when the stimulus images were presented using simultaneous pair comparison, observers were influenced by the surface properties of the images and conflated changes in image contrast and sharpness with changes in object gloss. On the other hand, when the stimulus images were presented sequentially, observers were able to disregard the image plane properties and more accurately match the gloss of the objects represented by the different quality images. These findings suggest that in understanding image quality it is useful to distinguish between quality of the imaging medium and the quality of the visual information represented by that medium.

Defining Quality in Cardiovascular Imaging: A Scientific Statement From the American Heart Association.

PubMed

Shaw, Leslee J; Blankstein, Ron; Jacobs, Jill E; Leipsic, Jonathon A; Kwong, Raymond Y; Taqueti, Viviany R; Beanlands, Rob S B; Mieres, Jennifer H; Flamm, Scott D; Gerber, Thomas C; Spertus, John; Di Carli, Marcelo F

2017-12-01

The aims of the current statement are to refine the definition of quality in cardiovascular imaging and to propose novel methodological approaches to inform the demonstration of quality in imaging in future clinical trials and registries. We propose defining quality in cardiovascular imaging using an analytical framework put forth by the Institute of Medicine whereby quality was defined as testing being safe, effective, patient-centered, timely, equitable, and efficient. The implications of each of these components of quality health care are as essential for cardiovascular imaging as they are for other areas within health care. Our proposed statement may serve as the foundation for integrating these quality indicators into establishing designations of quality laboratory practices and developing standards for value-based payment reform for imaging services. We also include recommendations for future clinical research to fulfill quality aims within cardiovascular imaging, including clinical hypotheses of improving patient outcomes, the importance of health status as an end point, and deferred testing options. Future research should evolve to define novel methods optimized for the role of cardiovascular imaging for detecting disease and guiding treatment and to demonstrate the role of cardiovascular imaging in facilitating healthcare quality. © 2017 American Heart Association, Inc.

Towards Improving the Quality of Work Life in Education.

ERIC Educational Resources Information Center

Wood, J. M.

Addressing the need to consider ways in which the quality of educator work life can be improved, the author uses J. Walton's eight-point definition of the quality of work life as a framework for discussion. The eight points include (1) adequate and fair compensation, in which financial incentives are provided for advanced coursework; (2) safe and…

Objective quality assessment for multiexposure multifocus image fusion.

PubMed

Hassen, Rania; Wang, Zhou; Salama, Magdy M A

2015-09-01

There has been a growing interest in image fusion technologies, but how to objectively evaluate the quality of fused images has not been fully understood. Here, we propose a method for objective quality assessment of multiexposure multifocus image fusion based on the evaluation of three key factors of fused image quality: 1) contrast preservation; 2) sharpness; and 3) structure preservation. Subjective experiments are conducted to create an image fusion database, based on which, performance evaluation shows that the proposed fusion quality index correlates well with subjective scores, and gives a significant improvement over the existing fusion quality measures.

Perceptual quality prediction on authentically distorted images using a bag of features approach

PubMed Central

Ghadiyaram, Deepti; Bovik, Alan C.

2017-01-01

Current top-performing blind perceptual image quality prediction models are generally trained on legacy databases of human quality opinion scores on synthetically distorted images. Therefore, they learn image features that effectively predict human visual quality judgments of inauthentic and usually isolated (single) distortions. However, real-world images usually contain complex composite mixtures of multiple distortions. We study the perceptually relevant natural scene statistics of such authentically distorted images in different color spaces and transform domains. We propose a “bag of feature maps” approach that avoids assumptions about the type of distortion(s) contained in an image and instead focuses on capturing consistencies—or departures therefrom—of the statistics of real-world images. Using a large database of authentically distorted images, human opinions of them, and bags of features computed on them, we train a regressor to conduct image quality prediction. We demonstrate the competence of the features toward improving automatic perceptual quality prediction by testing a learned algorithm using them on a benchmark legacy database as well as on a newly introduced distortion-realistic resource called the LIVE In the Wild Image Quality Challenge Database. We extensively evaluate the perceptual quality prediction model and algorithm and show that it is able to achieve good-quality prediction power that is better than other leading models. PMID:28129417

Seasonality of vegetation types of South America depicted by moderate resolution imaging spectroradiometer (MODIS) time series

NASA Astrophysics Data System (ADS)

Adami, Marcos; Bernardes, Sérgio; Arai, Egidio; Freitas, Ramon M.; Shimabukuro, Yosio E.; Espírito-Santo, Fernando D. B.; Rudorff, Bernardo F. T.; Anderson, Liana O.

2018-07-01

The development, implementation and enforcement of policies involving the rational use of the land and the conservation of natural resources depend on an adequate characterization and understanding of the land cover, including its dynamics. This paper presents an approach for monitoring vegetation dynamics using high-quality time series of MODIS surface reflectance data by generating fraction images using Linear Spectral Mixing Model (LSMM) over South America continent. The approach uses physically-based fraction images, which highlight target information and reduce data dimensionality. Further dimensionality was also reduced by using the vegetation fraction images as input to a Principal Component Analysis (PCA). The RGB composite of the first three PCA components, accounting for 92.9% of the dataset variability, showed good agreement with the main ecological regions of South America continent. The analysis of 21 temporal profiles of vegetation fraction values and precipitation data over South America showed the ability of vegetation fractions to represent phenological cycles over a variety of environments. Comparisons between vegetation fractions and precipitation data indicated the close relationship between water availability and leaf mass/chlorophyll content for several vegetation types. In addition, phenological changes and disturbance resulting from anthropogenic pressure were identified, particularly those associated with agricultural practices and forest removal. Therefore the proposed method supports the management of natural and non-natural ecosystems, and can contribute to the understanding of key conservation issues in South America, including deforestation, disturbance and fire occurrence and management.

Geo-oculus: high resolution multi-spectral earth imaging mission from geostationary orbit

NASA Astrophysics Data System (ADS)

Vaillon, L.; Schull, U.; Knigge, T.; Bevillon, C.

2017-11-01

Geo-Oculus is a GEO-based Earth observation mission studied by Astrium for ESA in 2008-2009 to complement the Sentinel missions, the space component of the GMES (Global Monitoring for Environment & Security). Indeed Earth imaging from geostationary orbit offers new functionalities not covered by existing LEO observation missions, like real-time monitoring and fast revisit capability of any location within the huge area in visibility of the satellite. This high revisit capability is exploited by the Meteosat meteorogical satellites, but with a spatial resolution (500 m nadir for the third generation) far from most of GMES needs (10 to 100 m). To reach such ground resolution from GEO orbit with adequate image quality, large aperture instruments (> 1 m) and high pointing stability (<< 1 μrad) are required, which are the major challenges of such missions. To address the requirements from the GMES user community, the Geo-Oculus mission is a combination of routine observations (daily systematic coverage of European coastal waters) with "on-demand" observation for event monitoring (e.g. disasters, fires and oil slicks). The instrument is a large aperture imaging telescope (1.5 m diameter) offering a nadir spatial sampling of 10.5 m (21 m worst case over Europe, below 52.5°N) in a PAN visible channel used for disaster monitoring. The 22 multi-spectral channels have resolutions over Europe ranging from 40 m in UV/VNIR (0.3 to 1 μm) to 750 m in TIR (10-12 μm).

Quality of care for major depression and its determinants: a multilevel analysis

PubMed Central

2012-01-01

Background Numerous studies highlight an important gap in the quality of care for depression in primary care. However, basic indicators were often used. Few of these studies examined factors associated with receiving adequate treatment, particularly with a simultaneous consideration of individual and organizational characteristics. The purpose of this study was to estimate the proportion of primary care patients with a major depressive episode (MDE) who receive adequate treatment and to examine the individual and organizational (i.e., clinic-level) characteristics associated with the receipt of at least one minimally adequate treatment for depression. Methods The sample used for this study included 915 adults consulting a general practitioner (GP), regardless of the motive of consultation, meeting DSM-IV criteria for MDE during the 12 months preceding the survey (T1), and nested within 65 primary care clinics. Data reported in this study were obtained from the “Dialogue” project. Adherence rates for 27 quality indicators selected to cover the most important components of depression treatment were estimated. Multilevel analyses were conducted. Results Adherence to guidelines was high (>75%) for one third of the quality indicators that were measured but was low (<60%) for nearly half of the measures. Just over half of the sample (52.2%) received at least one minimally adequate treatment for depression. At the individual level, determinants of receipt of minimally adequate care included age, having a family physician, a supplementary insurance coverage, a comorbid anxiety disorder and the severity of depression. At the clinic level, determinants included the availability of psychotherapy on-site, the use of treatment algorithms, and the mode of remuneration. Conclusions Our findings suggest that interventions are needed to increase the extent to which primary mental health care conforms to evidence-based recommendations. These interventions should target specific populations (i.e. the younger adults and the elderly), enhance accessibility to psychotherapy and to a regular family physician, and support primary care physicians in their clinical practice with patients suffering from depression in different ways such as developing knowledge to treat depression and adapting mode of remuneration. PMID:22985262

A Low-Cost Tele-Imaging Platform for Developing Countries

PubMed Central

Adambounou, Kokou; Adjenou, Victor; Salam, Alex P.; Farin, Fabien; N’Dakena, Koffi Gilbert; Gbeassor, Messanvi; Arbeille, Philippe

2014-01-01

Purpose: To design a “low-cost” tele-imaging method allowing real-time tele-ultrasound expertise, delayed tele-ultrasound diagnosis, and tele-radiology between remote peripherals hospitals and clinics (patient centers) and university hospital centers (expert center). Materials and methods: A system of communication via internet (IP camera and remote access software) enabling transfer of ultrasound videos and images between two centers allows a real-time tele-radiology expertise in the presence of a junior sonographer or radiologist at the patient center. In the absence of a sonographer or radiologist at the patient center, a 3D reconstruction program allows a delayed tele-ultrasound diagnosis with images acquired by a lay operator (e.g., midwife, nurse, technician). The system was tested both with high and low bandwidth. The system can further accommodate non-ultrasound tele-radiology (conventional radiography, mammography, and computer tomography for example). The system was tested on 50 patients between CHR Tsevie in Togo (40 km from Lomé-Togo and 4500 km from Tours-France) and CHU Campus at Lomé and CHU Trousseau in Tours. Results: A real-time tele-expertise was successfully performed with a delay of approximately 1.5 s with an internet bandwidth of around 1 Mbps (IP Camera) and 512 kbps (remote access software). A delayed tele-ultrasound diagnosis was also performed with satisfactory results. The transmission of radiological images from the patient center to the expert center was of adequate quality. Delayed tele-ultrasound and tele-radiology was possible even in the presence of a low-bandwidth internet connection. Conclusion: This tele-imaging method, requiring nothing by readily available and inexpensive technology and equipment, offers a major opportunity for telemedicine in developing countries. PMID:25250306

Intraductal biliopancreatic imaging: European Society of Gastrointestinal Endoscopy (ESGE) technology review.

PubMed

Tringali, Andrea; Lemmers, Arnaud; Meves, Volker; Terheggen, Grischa; Pohl, Jürgen; Manfredi, Guido; Häfner, Michael; Costamagna, Guido; Devière, Jacques; Neuhaus, Horst; Caillol, Fabrice; Giovannini, Marc; Hassan, Cesare; Dumonceau, Jean-Marc

2015-08-01

This technology review expresses the current view of the European Society of Gastrointestinal Endoscopy (ESGE) on the available techniques for intraductal biliopancreatic imaging. The three cholangioscopy techniques are described: the "dual-operator" and " single-operator" mother-baby approaches using dedicated instruments, and the "direct" technique using currently available ultrathin gastroscopes. The mother-baby method is standardized and reproducible, while direct cholangioscopy is technically demanding and its safety requires further evaluation. As well as direct visualization of the bile ducts, cholangioscopy has the further advantage of allowing targeted biopsy. Image quality is still suboptimal for single-operator cholangioscopy, while the other techniques have achieved adequately detailed imaging. The costs of mother-baby cholangioscopy are high and its application in clinical practice should be restricted to selected cases (i.e. indeterminate biliary strictures/intraluminal lesions, difficult biliary stones) and to the setting of tertiary care centers. Peroral pancreatoscopy may find an indication in situations where other imaging modalities (mainly EUS) are inconclusive (i.e. delineation of main duct intraductal papillary mucinous neoplasia extension, sampling of indeterminate main pancreatic duct strictures). Intraductal ultrasonography (IDUS) has a poorer performance than EUS in the staging of pancreatic malignancies and can increase the risk of pancreatitis. A promising indication for IDUS could be the evaluation of indeterminate biliary strictures and ampullary tumors. Probe-based confocal laser endomicroscopy (pCLE) of the bile ducts is a difficult and expensive technique. Appropriate training needs to be established, since interpretation of images is challenging. pCLE can be an important diagnostic tool in the setting of indeterminate biliary strictures. © Georg Thieme Verlag KG Stuttgart · New York.

Possibilities and limits of imaging endodontic structures with CBCT.

PubMed

Weber, Marie-Theres; Stratz, Nadja; Fleiner, Jonathan; Schulze, Dirk; Hannig, Christian

2015-01-01

An adequate portrayal of the root canal anatomy by diagnostic imaging is a prerequisite for a successful diagnosis and therapy in endodontics. The introduction of dental cone beam computed tomography (CBCT) has considerably expanded the scope of imaging diagnostics. The aim of the following study was to evaluate the imaging of endodontic structures with CBCT. One hundred and twenty teeth were examined with a CBCT device (ProMax 3D). Subsequently, the findings of the three-dimensional images were evaluated and compared to those of dental radiographs and tangential section preparations of the examined teeth. Results with high prevalence, such as existing roots and root canals, as well as results with low prevalence, e.g., extremely fine anatomical structures of the endodontic tissue, could be visualized precisely by dental CBCT; side canals, ramifications, communications, pulp stones, and obliterations could also be detected. Additionally, the length of curved root canals could be determined accurately. Likewise, root fractures were visualized reliably with CBCT. However, carious lesions could not be diagnosed adequately, and the evaluation of fillings and prosthetic restorations was complicated due to scattered X-ray artifacts. CBCT datasets qualify to visualize and diagnose small anatomical structures of the endodontic tissue.

Guidance for Efficient Small Animal Imaging Quality Control.

PubMed

Osborne, Dustin R; Kuntner, Claudia; Berr, Stuart; Stout, David

2017-08-01

Routine quality control is a critical aspect of properly maintaining high-performance small animal imaging instrumentation. A robust quality control program helps produce more reliable data both for academic purposes and as proof of system performance for contract imaging work. For preclinical imaging laboratories, the combination of costs and available resources often limits their ability to produce efficient and effective quality control programs. This work presents a series of simplified quality control procedures that are accessible to a wide range of preclinical imaging laboratories. Our intent is to provide minimum guidelines for routine quality control that can assist preclinical imaging specialists in setting up an appropriate quality control program for their facility.

Establishing Computer-Assisted Instruction to Teach Academics to Students with Autism as an Evidence-Based Practice.

PubMed

Root, Jenny R; Stevenson, Bradley S; Davis, Luann Ley; Geddes-Hall, Jennifer; Test, David W

2017-02-01

Computer-assisted instruction (CAI) is growing in popularity and has demonstrated positive effects for students with disabilities, including those with autism spectrum disorder (ASD). In this review, criteria for group experimental and single case studies were used to determine quality (Horner et al., Exceptional Children 71:165-179, 2005; Gersten et al., Exceptional Children 71:149-164, 2005; National Technical Assistance Center on Transition Center 2015). Included studies of high and adequate quality were further analyzed in terms of content, context, and specific instructional practices. Based on the NTACT criteria, this systematic review has established CAI as an evidence-based practice for teaching academics to students with ASD with support from 10 single-case and two group design studies of high or adequate quality. Suggestions for future research and implications for practice are discussed.

Medical Education and Research: The Foundations of Quality Health Care

PubMed Central

Mustard, J. F.; Laidlaw, J. C.; Godden, J. O.

1966-01-01

In May 1964 the Royal Commission on Health Services declared that “health research is essential to health progress”. However, since that time the means of providing adequate health care have received far less attention than have methods of payment for physicians' services. Because medical education and research is the source from which all other health benefits flow, urgent attention must be paid to the adequate support of teacher-scientists, as set forth in the Woods, Gordon (Gundy) report. It is the numbers and quality of these men and women, more than any other factor, that will determine the shape of medical science and, hence, medical practice in Canada in the future. Expensive as it is, Canadian medicine and Canadian medical scientists must have generous support if medical care in this country is to be of high quality. PMID:5908724

Task-based measures of image quality and their relation to radiation dose and patient risk

PubMed Central

Barrett, Harrison H.; Myers, Kyle J.; Hoeschen, Christoph; Kupinski, Matthew A.; Little, Mark P.

2015-01-01

The theory of task-based assessment of image quality is reviewed in the context of imaging with ionizing radiation, and objective figures of merit (FOMs) for image quality are summarized. The variation of the FOMs with the task, the observer and especially with the mean number of photons recorded in the image is discussed. Then various standard methods for specifying radiation dose are reviewed and related to the mean number of photons in the image and hence to image quality. Current knowledge of the relation between local radiation dose and the risk of various adverse effects is summarized, and some graphical depictions of the tradeoffs between image quality and risk are introduced. Then various dose-reduction strategies are discussed in terms of their effect on task-based measures of image quality. PMID:25564960

Multiparametric Magnetic Resonance Imaging for Active Surveillance of Prostate Cancer.

PubMed

An, Julie Y; Sidana, Abhinav; Choyke, Peter L; Wood, Bradford J.; Pinto, Peter A; Türkbey, İsmail Barış

2017-09-29

Active surveillance has gained popularity as an acceptable management option for men with low-risk prostate cancer. Successful utilization of this strategy can delay or prevent unnecessary interventions - thereby reducing morbidity associated with overtreatment. The usefulness of active surveillance primarily depends on correct identification of patients with low-risk disease. However, current population-wide algorithms and tools do not adequately exclude high-risk disease, thereby limiting the confidence of clinicians and patients to go on active surveillance. Novel imaging tools such as mpMRI provide information about the size and location of potential cancers enabling more informed treatment decisions. The term "multiparametric" in prostate mpMRI refers to the summation of several MRI series into one examination whose initial goal is to identify potential clinically-significant lesions suitable for targeted biopsy. The main advantages of MRI are its superior anatomic resolution and the lack of ionizing radiation. Recently, the Prostate Imaging-Reporting and Data System has been instituted as an international standard for unifying mpMRI results. The imaging sequences in mpMRI defined by Prostate Imaging Reporting and Data System version 2 includes: T2-weighted MRI, diffusion-weighted MRI, derived apparent-diffusion coefficient from diffusion-weighted MRI, and dynamic contrast-enhanced MRI. The use of mpMRI prior to starting active surveillance could prevent those with missed, high-grade lesions from going on active surveillance, and reassure those with minimal disease who may be hesitant to take part in active surveillance. Although larger validation studies are still necessary, preliminary results suggest mpMRI has a role in selecting patients for active surveillance. Less certain is the role of mpMRI in monitoring patients on active surveillance, as data on this will take a long time to mature. The biggest obstacles to routine use of prostate MRI are quality control, cost, reproducibility, and access. Nevertheless, there is great a potential for mpMRI to improve outcomes and quality of treatment. The major roles of MRI will continue to expand and its emerging use in standard of care approaches becomes more clearly defined and supported by increasing levels of data.

Contrast-enhanced MR Angiography of the Abdomen with Highly Accelerated Acquisition Techniques

PubMed Central

Mostardi, Petrice M.; Glockner, James F.; Young, Phillip M.

2011-01-01

Purpose: To demonstrate that highly accelerated (net acceleration factor [Rnet] ≥ 10) acquisition techniques can be used to generate three-dimensional (3D) subsecond timing images, as well as diagnostic-quality high-spatial-resolution contrast material–enhanced (CE) renal magnetic resonance (MR) angiograms with a single split dose of contrast material. Materials and Methods: All studies were approved by the institutional review board and were HIPAA compliant; written consent was obtained from all participants. Twenty-two studies were performed in 10 female volunteers (average age, 47 years; range, 27–62 years) and six patients with renovascular disease (three women; average age, 48 years; range, 37–68 years; three men; average age, 60 years; range, 50–67 years; composite average age, 54 years; range, 38–68 years). The two-part protocol consisted of a low-dose (2 mL contrast material) 3D timing image with approximate 1-second frame time, followed by a high-spatial-resolution (1.0–1.6-mm isotropic voxels) breath-hold 3D renal MR angiogram (18 mL) over the full abdominal field of view. Both acquisitions used two-dimensional (2D) sensitivity encoding acceleration factor (R) of eight and 2D homodyne (HD) acceleration (RHD) of 1.4–1.8 for Rnet = R · RHD of 10 or higher. Statistical analysis included determination of mean values and standard deviations of image quality scores performed by two experienced reviewers with use of eight evaluation criteria. Results: The 2-mL 3D time-resolved image successfully portrayed progressive arterial filling in all 22 studies and provided an anatomic overview of the vasculature. Successful timing was also demonstrated in that the renal MR angiogram showed adequate or excellent portrayal of the main renal arteries in 21 of 22 studies. Conclusion: Two-dimensional acceleration techniques with Rnet of 10 or higher can be used in CE MR angiography to acquire (a) a 3D image series with 1-second frame time, allowing accurate bolus timing, and (b) a high-spatial-resolution renal angiogram. © RSNA, 2011 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11110242/-/DC1 PMID:21900616

A prospective case study of high boost, high frequency emphasis and two-way diffusion filters on MR images of glioblastoma multiforme.

PubMed

Anoop, B N; Joseph, Justin; Williams, J; Jayaraman, J Sivaraman; Sebastian, Ansa Maria; Sihota, Praveer

2018-06-01

Glioblastoma multiforme (GBM) appears undifferentiated and non-enhancing on magnetic resonance (MR) imagery. As MRI does not offer adequate image quality to allow visual discrimination of the boundary between GBM focus and perifocal vasogenic edema, surgical and radiotherapy planning become difficult. The presence of noise in MR images influences the computation of radiation dosage and precludes the edge based segmentation schemes in automated software for radiation treatment planning. The performance of techniques meant for simultaneous denoising and sharpening, like high boost filters, high frequency emphasize filters and two-way anisotropic diffusion is sensitive to the selection of their operational parameters. Improper selection may cause overshoot and saturation artefacts or noisy grey level transitions can be left unsuppressed. This paper is a prospective case study of the performance of high boost filters, high frequency emphasize filters and two-way anisotropic diffusion on MR images of GBM, for their ability to suppress noise from homogeneous regions and to selectively sharpen the true morphological edges. An objective method for determining the optimum value of the operational parameters of these techniques is also demonstrated. Saturation Evaluation Index (SEI), Perceptual Sharpness Index (PSI), Edge Model based Blur Metric (EMBM), Sharpness of Ridges (SOR), Structural Similarity Index Metric (SSIM), Peak Signal to Noise Ratio (PSNR) and Noise Suppression Ratio (NSR) are the objective functions used. They account for overshoot and saturation artefacts, sharpness of the image, width of salient edges (haloes), susceptibility of edge quality to noise, feature preservation and degree of noise suppression. Two-way diffusion is found to be superior to others in all these respects. The SEI, PSI, EMBM, SOR, SSIM, PSNR and NSR exhibited by two-way diffusion are 0.0016 ± 0.0012, 0.2049 ± 0.0187, 0.0905 ± 0.0408, 2.64 × 10 12  ± 1.6 × 10 12 , 0.9955 ± 0.0024, 38.214 ± 5.2145 and 0.3547 ± 0.0069, respectively.

No-reference multiscale blur detection tool for content based image retrieval

NASA Astrophysics Data System (ADS)

Ezekiel, Soundararajan; Stocker, Russell; Harrity, Kyle; Alford, Mark; Ferris, David; Blasch, Erik; Gorniak, Mark

2014-06-01

In recent years, digital cameras have been widely used for image capturing. These devices are equipped in cell phones, laptops, tablets, webcams, etc. Image quality is an important component of digital image analysis. To assess image quality for these mobile products, a standard image is required as a reference image. In this case, Root Mean Square Error and Peak Signal to Noise Ratio can be used to measure the quality of the images. However, these methods are not possible if there is no reference image. In our approach, a discrete-wavelet transformation is applied to the blurred image, which decomposes into the approximate image and three detail sub-images, namely horizontal, vertical, and diagonal images. We then focus on noise-measuring the detail images and blur-measuring the approximate image to assess the image quality. We then compute noise mean and noise ratio from the detail images, and blur mean and blur ratio from the approximate image. The Multi-scale Blur Detection (MBD) metric provides both an assessment of the noise and blur content. These values are weighted based on a linear regression against full-reference y values. From these statistics, we can compare to normal useful image statistics for image quality without needing a reference image. We then test the validity of our obtained weights by R2 analysis as well as using them to estimate image quality of an image with a known quality measure. The result shows that our method provides acceptable results for images containing low to mid noise levels and blur content.

Determinants of image quality of rotational angiography for on-line assessment of frame geometry after transcatheter aortic valve implantation.

PubMed

Rodríguez-Olivares, Ramón; El Faquir, Nahid; Rahhab, Zouhair; Maugenest, Anne-Marie; Van Mieghem, Nicolas M; Schultz, Carl; Lauritsch, Guenter; de Jaegere, Peter P T

2016-07-01

To study the determinants of image quality of rotational angiography using dedicated research prototype software for motion compensation without rapid ventricular pacing after the implantation of four commercially available catheter-based valves. Prospective observational study including 179 consecutive patients who underwent transcatheter aortic valve implantation (TAVI) with either the Medtronic CoreValve (MCS), Edward-SAPIEN Valve (ESV), Boston Sadra Lotus (BSL) or Saint-Jude Portico Valve (SJP) in whom rotational angiography (R-angio) with motion compensation 3D image reconstruction was performed. Image quality was evaluated from grade 1 (excellent image quality) to grade 5 (strongly degraded). Distinction was made between good (grades 1, 2) and poor image quality (grades 3-5). Clinical (gender, body mass index, Agatston score, heart rate and rhythm, artifacts), procedural (valve type) and technical variables (isocentricity) were related with the image quality assessment. Image quality was good in 128 (72 %) and poor in 51 (28 %) patients. By univariable analysis only valve type (BSL) and the presence of an artefact negatively affected image quality. By multivariate analysis (in which BMI was forced into the model) BSL valve (Odds 3.5, 95 % CI [1.3-9.6], p = 0.02), presence of an artifact (Odds 2.5, 95 % CI [1.2-5.4], p = 0.02) and BMI (Odds 1.1, 95 % CI [1.0-1.2], p = 0.04) were independent predictors of poor image quality. Rotational angiography with motion compensation 3D image reconstruction using a dedicated research prototype software offers good image quality for the evaluation of frame geometry after TAVI in the majority of patients. Valve type, presence of artifacts and higher BMI negatively affect image quality.

Positron emission tomography and optical tissue imaging

DOEpatents

Falen, Steven W [Carmichael, CA; Hoefer, Richard A [Newport News, VA; Majewski, Stanislaw [Yorktown, VA; McKisson, John [Hampton, VA; Kross, Brian [Yorktown, VA; Proffitt, James [Newport News, VA; Stolin, Alexander [Newport News, VA; Weisenberger, Andrew G [Yorktown, VA

2012-05-22

A mobile compact imaging system that combines both PET imaging and optical imaging into a single system which can be located in the operating room (OR) and provides faster feedback to determine if a tumor has been fully resected and if there are adequate surgical margins. While final confirmation is obtained from the pathology lab, such a device can reduce the total time necessary for the procedure and the number of iterations required to achieve satisfactory resection of a tumor with good margins.

Defense Logistics Agency Can Improve Its Product Quality Deficiency Report Processing

DTIC Science & Technology

2015-07-01

Contracts for M2 Machine Gun Spare Parts in Support of Operations in Southwest Asia,” January 11, 2010 Appendixes DODIG-2015-140 │ 29 Appendix B...personnel are adequately processing product quality deficiency reports and identifying the root cause for defective spare parts . This is the first...quality deficiency report program and prevents meaningful analysis of the primary causes of spare- part quality deficiencies. In addition, the

Contrast-enhanced harmonic ultrasound imaging in ablation therapy for primary hepatocellular carcinoma.

PubMed

Minami, Yasunori; Kudo, Masatoshi

2009-12-31

The success rate of percutaneous radiofrequency (RF) ablation for hepatocellular carcinoma (HCC) depends on correct targeting via an imaging technique. However, RF electrode insertion is not completely accurate for residual HCC nodules because B-mode ultrasound (US), color Doppler, and power Doppler US findings cannot adequately differentiate between treated and viable residual tumor tissue. Electrode insertion is also difficult when we must identify the true HCC nodule among many large regenerated nodules in cirrhotic liver. Two breakthroughs in the field of US technology, harmonic imaging and the development of second-generation contrast agents, have recently been described and have demonstrated the potential to dramatically broaden the scope of US diagnosis of hepatic lesions. Contrast-enhanced harmonic US imaging with an intravenous contrast agent can evaluate small hypervascular HCC even when B-mode US cannot adequately characterize tumor. Therefore, contrast-enhanced harmonic US can facilitate RF ablation electrode placement in hypervascular HCC, which is poorly depicted by B-mode US. The use of contrast-enhanced harmonic US in ablation therapy for liver cancer is an efficient approach.

Digital processing of radiographic images from PACS to publishing.

PubMed

Christian, M E; Davidson, H C; Wiggins, R H; Berges, G; Cannon, G; Jackson, G; Chapman, B; Harnsberger, H R

2001-03-01

Several studies have addressed the implications of filmless radiologic imaging on telemedicine, diagnostic ability, and electronic teaching files. However, many publishers still require authors to submit hard-copy images for publication of articles and textbooks. This study compares the quality digital images directly exported from picture archive and communications systems (PACS) to images digitized from radiographic film. The authors evaluated the quality of publication-grade glossy photographs produced from digital radiographic images using 3 different methods: (1) film images digitized using a desktop scanner and then printed, (2) digital images obtained directly from PACS then printed, and (3) digital images obtained from PACS and processed to improve sharpness prior to printing. Twenty images were printed using each of the 3 different methods and rated for quality by 7 radiologists. The results were analyzed for statistically significant differences among the image sets. Subjective evaluations of the filmless images found them to be of equal or better quality than the digitized images. Direct electronic transfer of PACS images reduces the number of steps involved in creating publication-quality images as well as providing the means to produce high-quality radiographic images in a digital environment.

Human visual system consistent quality assessment for remote sensing image fusion

NASA Astrophysics Data System (ADS)

Liu, Jun; Huang, Junyi; Liu, Shuguang; Li, Huali; Zhou, Qiming; Liu, Junchen

2015-07-01

Quality assessment for image fusion is essential for remote sensing application. Generally used indices require a high spatial resolution multispectral (MS) image for reference, which is not always readily available. Meanwhile, the fusion quality assessments using these indices may not be consistent with the Human Visual System (HVS). As an attempt to overcome this requirement and inconsistency, this paper proposes an HVS-consistent image fusion quality assessment index at the highest resolution without a reference MS image using Gaussian Scale Space (GSS) technology that could simulate the HVS. The spatial details and spectral information of original and fused images are first separated in GSS, and the qualities are evaluated using the proposed spatial and spectral quality index respectively. The overall quality is determined without a reference MS image by a combination of the proposed two indices. Experimental results on various remote sensing images indicate that the proposed index is more consistent with HVS evaluation compared with other widely used indices that may or may not require reference images.

Low-cost oblique illumination: an image quality assessment.

PubMed

Ruiz-Santaquiteria, Jesus; Espinosa-Aranda, Jose Luis; Deniz, Oscar; Sanchez, Carlos; Borrego-Ramos, Maria; Blanco, Saul; Cristobal, Gabriel; Bueno, Gloria

2018-01-01

We study the effectiveness of several low-cost oblique illumination filters to improve overall image quality, in comparison with standard bright field imaging. For this purpose, a dataset composed of 3360 diatom images belonging to 21 taxa was acquired. Subjective and objective image quality assessments were done. The subjective evaluation was performed by a group of diatom experts by psychophysical test where resolution, focus, and contrast were assessed. Moreover, some objective nonreference image quality metrics were applied to the same image dataset to complete the study, together with the calculation of several texture features to analyze the effect of these filters in terms of textural properties. Both image quality evaluation methods, subjective and objective, showed better results for images acquired using these illumination filters in comparison with the no filtered image. These promising results confirm that this kind of illumination filters can be a practical way to improve the image quality, thanks to the simple and low cost of the design and manufacturing process. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Segmented Separable Footprint Projector for Digital Breast Tomosynthesis and Its application for Subpixel Reconstruction

PubMed Central

Zheng, Jiabei; Fessler, Jeffrey A; Chan, Heang-Ping

2017-01-01

Purpose Digital forward and back projectors play a significant role in iterative image reconstruction. The accuracy of the projector affects the quality of the reconstructed images. Digital breast tomosynthesis (DBT) often uses the ray-tracing (RT) projector that ignores finite detector element size. This paper proposes a modified version of the separable footprint (SF) projector, called the segmented separable footprint (SG) projector, that calculates efficiently the Radon transform mean value over each detector element. The SG projector is specifically designed for DBT reconstruction because of the large height-to-width ratio of the voxels generally used in DBT. This study evaluates the effectiveness of the SG projector in reducing projection error and improving DBT reconstruction quality. Methods We quantitatively compared the projection error of the RT and the SG projector at different locations and their performance in regular and subpixel DBT reconstruction. Subpixel reconstructions used finer voxels in the imaged volume than the detector pixel size. Subpixel reconstruction with RT projector uses interpolated projection views as input to provide adequate coverage of the finer voxel grid with the traced rays. Subpixel reconstruction with the SG projector, however, uses the measured projection views without interpolation. We simulated DBT projections of a test phantom using CatSim (GE Global Research, Niskayuna, NY) under idealized imaging conditions without noise and blur, to analyze the effects of the projectors and subpixel reconstruction without other image degrading factors. The phantom contained an array of horizontal and vertical line pair patterns (1 to 9.5 line pairs/mm) and pairs of closely spaced spheres (diameters 0.053 to 0.5 mm) embedded at the mid-plane of a 5-cm-thick breast-tissue-equivalent uniform volume. The images were reconstructed with regular simultaneous algebraic reconstruction technique (SART) and subpixel SART using different projectors. The resolution and contrast of the test objects in the reconstructed images and the computation times were compared under different reconstruction conditions. Results The SG projector reduced the projector error by 1 to 2 orders of magnitude at most locations. In the worst case, the SG projector still reduced the projection error by about 50%. In the DBT reconstructed slices parallel to the detector plane, the SG projector not only increased the contrast of the line pairs and spheres, but also produced more smooth and continuous reconstructed images whereas the discrete and sparse nature of the RT projector caused artifacts appearing as patterned noise. For subpixel reconstruction, the SG projector significantly increased object contrast and computation speed, especially for high subpixel ratios, compared with the RT projector implemented with accelerated Siddon’s algorithm. The difference in the depth resolution among the projectors is negligible under the conditions studied. Our results also demonstrated that subpixel reconstruction can improve the spatial resolution of the reconstructed images, and can exceed the Nyquist limit of the detector under some conditions. Conclusions The SG projector was more accurate and faster than the RT projector. The SG projector also substantially reduced computation time and improved the image quality for the tomosynthesized images with and without subpixel reconstruction. PMID:28058719

7 CFR 225.7 - Program monitoring and assistance.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., food service management company representatives, auditors, and health inspectors who will participate... adequately for the Program. (c) Food specifications and meal quality standards. With the assistance of the... and model meal quality standards which shall become part of all contracts between vended sponsors and...

Heating, Ventilation and Air-Conditioning Systems, Part of Indoor Air Quality Design Tools for Schools

EPA Pesticide Factsheets

The main purposes of a Heating, Ventilation, and Air-Conditioning system are to help maintain good indoor air quality through adequate ventilation with filtration and provide thermal comfort. HVAC systems are among the largest energy consumers in schools.

40 CFR 60.21 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... control equipment or process change; and (5) Final compliance. (i) Region means an air quality control... standard of performance for new stationary sources, but for which air quality criteria have not been issued... account the cost of such reduction) the Administrator has determined has been adequately demonstrated for...

Microbes and Water Quality in Developed Countries

EPA Science Inventory

Safe drinking water has been a concern for mankind through out the world for centuries. In the developed world, governments consider access to safe and clean drinking water to be a basic human right. Government regulations generally address the quality of the source water, adequ...

Quantifying the quality of medical x-ray images: An evaluation based on normal anatomy for lumbar spine and chest radiography

NASA Astrophysics Data System (ADS)

Tingberg, Anders Martin

Optimisation in diagnostic radiology requires accurate methods for determination of patient absorbed dose and clinical image quality. Simple methods for evaluation of clinical image quality are at present scarce and this project aims at developing such methods. Two methods are used and further developed; fulfillment of image criteria (IC) and visual grading analysis (VGA). Clinical image quality descriptors are defined based on these two methods: image criteria score (ICS) and visual grading analysis score (VGAS), respectively. For both methods the basis is the Image Criteria of the ``European Guidelines on Quality Criteria for Diagnostic Radiographic Images''. Both methods have proved to be useful for evaluation of clinical image quality. The two methods complement each other: IC is an absolute method, which means that the quality of images of different patients and produced with different radiographic techniques can be compared with each other. The separating power of IC is, however, weaker than that of VGA. VGA is the best method for comparing images produced with different radiographic techniques and has strong separating power, but the results are relative, since the quality of an image is compared to the quality of a reference image. The usefulness of the two methods has been verified by comparing the results from both of them with results from a generally accepted method for evaluation of clinical image quality, receiver operating characteristics (ROC). The results of the comparison between the two methods based on visibility of anatomical structures and the method based on detection of pathological structures (free-response forced error) indicate that the former two methods can be used for evaluation of clinical image quality as efficiently as the method based on ROC. More studies are, however, needed for us to be able to draw a general conclusion, including studies of other organs, using other radiographic techniques, etc. The results of the experimental evaluation of clinical image quality are compared with physical quantities calculated with a theoretical model based on a voxel phantom, and correlations are found. The results demonstrate that the computer model can be a useful toot in planning further experimental studies.

Research on assessment and improvement method of remote sensing image reconstruction

NASA Astrophysics Data System (ADS)

Sun, Li; Hua, Nian; Yu, Yanbo; Zhao, Zhanping

2018-01-01

Remote sensing image quality assessment and improvement is an important part of image processing. Generally, the use of compressive sampling theory in remote sensing imaging system can compress images while sampling which can improve efficiency. A method of two-dimensional principal component analysis (2DPCA) is proposed to reconstruct the remote sensing image to improve the quality of the compressed image in this paper, which contain the useful information of image and can restrain the noise. Then, remote sensing image quality influence factors are analyzed, and the evaluation parameters for quantitative evaluation are introduced. On this basis, the quality of the reconstructed images is evaluated and the different factors influence on the reconstruction is analyzed, providing meaningful referential data for enhancing the quality of remote sensing images. The experiment results show that evaluation results fit human visual feature, and the method proposed have good application value in the field of remote sensing image processing.

Does clinical pretest probability influence image quality and diagnostic accuracy in dual-source coronary CT angiography?

PubMed

Thomas, Christoph; Brodoefel, Harald; Tsiflikas, Ilias; Bruckner, Friederike; Reimann, Anja; Ketelsen, Dominik; Drosch, Tanja; Claussen, Claus D; Kopp, Andreas; Heuschmid, Martin; Burgstahler, Christof

2010-02-01

To prospectively evaluate the influence of the clinical pretest probability assessed by the Morise score onto image quality and diagnostic accuracy in coronary dual-source computed tomography angiography (DSCTA). In 61 patients, DSCTA and invasive coronary angiography were performed. Subjective image quality and accuracy for stenosis detection (>50%) of DSCTA with invasive coronary angiography as gold standard were evaluated. The influence of pretest probability onto image quality and accuracy was assessed by logistic regression and chi-square testing. Correlations of image quality and accuracy with the Morise score were determined using linear regression. Thirty-eight patients were categorized into the high, 21 into the intermediate, and 2 into the low probability group. Accuracies for the detection of significant stenoses were 0.94, 0.97, and 1.00, respectively. Logistic regressions and chi-square tests showed statistically significant correlations between Morise score and image quality (P < .0001 and P < .001) and accuracy (P = .0049 and P = .027). Linear regression revealed a cutoff Morise score for a good image quality of 16 and a cutoff for a barely diagnostic image quality beyond the upper Morise scale. Pretest probability is a weak predictor of image quality and diagnostic accuracy in coronary DSCTA. A sufficient image quality for diagnostic images can be reached with all pretest probabilities. Therefore, coronary DSCTA might be suitable also for patients with a high pretest probability. Copyright 2010 AUR. Published by Elsevier Inc. All rights reserved.

Modified-BRISQUE as no reference image quality assessment for structural MR images.

PubMed

Chow, Li Sze; Rajagopal, Heshalini

2017-11-01

An effective and practical Image Quality Assessment (IQA) model is needed to assess the image quality produced from any new hardware or software in MRI. A highly competitive No Reference - IQA (NR - IQA) model called Blind/Referenceless Image Spatial Quality Evaluator (BRISQUE) initially designed for natural images were modified to evaluate structural MR images. The BRISQUE model measures the image quality by using the locally normalized luminance coefficients, which were used to calculate the image features. The modified-BRISQUE model trained a new regression model using MR image features and Difference Mean Opinion Score (DMOS) from 775 MR images. Two types of benchmarks: objective and subjective assessments were used as performance evaluators for both original and modified-BRISQUE models. There was a high correlation between the modified-BRISQUE with both benchmarks, and they were higher than those for the original BRISQUE. There was a significant percentage improvement in their correlation values. The modified-BRISQUE was statistically better than the original BRISQUE. The modified-BRISQUE model can accurately measure the image quality of MR images. It is a practical NR-IQA model for MR images without using reference images. Copyright © 2017 Elsevier Inc. All rights reserved.

No-reference quality assessment based on visual perception

NASA Astrophysics Data System (ADS)

Li, Junshan; Yang, Yawei; Hu, Shuangyan; Zhang, Jiao

2014-11-01

The visual quality assessment of images/videos is an ongoing hot research topic, which has become more and more important for numerous image and video processing applications with the rapid development of digital imaging and communication technologies. The goal of image quality assessment (IQA) algorithms is to automatically assess the quality of images/videos in agreement with human quality judgments. Up to now, two kinds of models have been used for IQA, namely full-reference (FR) and no-reference (NR) models. For FR models, IQA algorithms interpret image quality as fidelity or similarity with a perfect image in some perceptual space. However, the reference image is not available in many practical applications, and a NR IQA approach is desired. Considering natural vision as optimized by the millions of years of evolutionary pressure, many methods attempt to achieve consistency in quality prediction by modeling salient physiological and psychological features of the human visual system (HVS). To reach this goal, researchers try to simulate HVS with image sparsity coding and supervised machine learning, which are two main features of HVS. A typical HVS captures the scenes by sparsity coding, and uses experienced knowledge to apperceive objects. In this paper, we propose a novel IQA approach based on visual perception. Firstly, a standard model of HVS is studied and analyzed, and the sparse representation of image is accomplished with the model; and then, the mapping correlation between sparse codes and subjective quality scores is trained with the regression technique of least squaresupport vector machine (LS-SVM), which gains the regressor that can predict the image quality; the visual metric of image is predicted with the trained regressor at last. We validate the performance of proposed approach on Laboratory for Image and Video Engineering (LIVE) database, the specific contents of the type of distortions present in the database are: 227 images of JPEG2000, 233 images of JPEG, 174 images of White Noise, 174 images of Gaussian Blur, 174 images of Fast Fading. The database includes subjective differential mean opinion score (DMOS) for each image. The experimental results show that the proposed approach not only can assess many kinds of distorted images quality, but also exhibits a superior accuracy and monotonicity.

Recent Developments in Vascular Imaging Techniques in Tissue Engineering and Regenerative Medicine

PubMed Central

Upputuri, Paul Kumar; Sivasubramanian, Kathyayini; Mark, Chong Seow Khoon; Pramanik, Manojit

2015-01-01

Adequate vascularisation is key in determining the clinical outcome of stem cells and engineered tissue in regenerative medicine. Numerous imaging modalities have been developed and used for the visualization of vascularisation in tissue engineering. In this review, we briefly discuss the very recent advances aiming at high performance imaging of vasculature. We classify the vascular imaging modalities into three major groups: nonoptical methods (X-ray, magnetic resonance, ultrasound, and positron emission imaging), optical methods (optical coherence, fluorescence, multiphoton, and laser speckle imaging), and hybrid methods (photoacoustic imaging). We then summarize the strengths and challenges of these methods for preclinical and clinical applications. PMID:25821821

Implementation of test for quality assurance in nuclear medicine gamma camera

NASA Astrophysics Data System (ADS)

Moreno, A. Montoya; Laguna, A. Rodríguez; Zamudio, Flavio E. Trujillo

2012-10-01

In nuclear medicine (NM) over 90% of procedures are performed for diagnostic purposes. To ensure adequate diagnostic quality of images and the optimization of the doses received by patients originated from the radioactive material is essential for regular monitoring and equipment performance through a quality assurance program (QAP). The QAP consists of 15 proposed performance tomographic and not tomographic gamma camera (GC) tests, and is based on recommendations of international organizations. We describe some results of the performance parameters of QAP applied to a GC model e.cam Siemens, of the Department of NM of the National Cancer Institute of Mexico (INCan). The results were: (1) The average intrinsic spatial resolution (Rin) was 4.67 ± 0.25 mm at the limit of acceptance criterion of 4.4 mm. (2) The sensitivity extrinsic (Sext), with maximum variations of 1.8% (less than 2% which is the criterion of acceptance). (3) Rotational Uniformity (Urot), with values of integral uniformity (IU) in the useful field of view detector (UFOV), with maximum percentage change of 0.97% and monthly variations equal angles, ranging from 0.13 to 0.99% less than 1%. (4) The displacement of the center of rotation (DCOR), indicated a maximum deviation of 0.155 ± 0.039 mm less than 4.795 mm, an absolute deviation of less than 0.5 where pixel 0.085 pixel is suggested, the criteria are assigned to low-energy collimator high resolution. (5) In tomographic uniformity (Utomo), UI values (%) and percentage noise level (rms%) were 7.54 ± 1.53 and 4.18 ± 1.69 which are consistent with the limits of acceptance of 7.0-12.0% and 3.0-6.0% respectively. The smallest cold sphere has a diameter of 11.4 mm. The implementation of a QAP allows for high quality diagnostic images, optimization of the doses given to patients, a reduction of exposure to occupationally exposed workers (POE, by its Spanish acronym), and generally improves the productivity of the service. This proposal can be used to develop a similar QAP in other facilities and may serve as a precedent for the proposed regulations for quality assurance (QA) teams in MN.

Methods for Examining the Psychometric Quality of Subscores: A Review and Application

ERIC Educational Resources Information Center

Wedman, Jonathan; Lyrén, Per-Erik

2015-01-01

When subscores on a test are reported to the test taker, the appropriateness of reporting them depends on whether they provide useful information above what is provided by the total score. Subscores that fail to do so lack adequate psychometric quality and should not be reported. There are several methods for examining the quality of subscores,…

Air quality in California forests: current efforts to initiate biomonitoring with lichens.

Treesearch

Sarah Jovan

2002-01-01

The primary objective of the Forest Health Monitoring indicator project is to develop models that use the composition of epiphytic lichen communities to detect and monitor air quality in forests. The designs of existing air quality monitoring networks in California do not provide adequate representation of rural areas to assess impacts to forests. This article is...

Ghostwriters Guaranteeing Grades? The Quality of Online Ghostwriting Services Available to Tertiary Students in Australia

ERIC Educational Resources Information Center

Lines, Lisa

2016-01-01

Ghostwriting is difficult to detect, it has the potential to be high quality, and universities do not currently have adequate policies in place to police it. Determining the quality of the ghostwriting services available to tertiary students is of vital importance because underestimating the potential for students to use these services to pass…

Management of transfusional iron overload in Latin America: current outlook and expert panel recommendations.

PubMed

Araújo, Aderson; Drelichman, Guillermo; Cançado, Rodolfo D; Watman, Nora; Magalhães, Silvia M M; Duhalde, Mauricio; Marfil, Javier; Feliú, Aurora; Clementina, Landolfi; Linares Ballesteros, Adriana; Di Stefano, Marco

2009-02-01

The results of a meeting of physicians convening in Latin America to develop expert opinions on the diagnosis, monitoring and treatment of iron overload are as follows. An accurate diagnosis can be obtained by neonatal screening for haemoglobinopathies, especially sickle cell disease and the thalassaemias. Disease-specific registries are needed to demonstrate the extent of the problem to health authorities. Disparities in the quantity and quality of blood products must be addressed, and uniform transfusion guidelines are necessary. Serum ferritin level is a feasible marker for iron overload in the region, while magnetic resonance imaging assessment can improve the diagnosis and monitoring of cardiac and liver iron content. Medical specialists, including radiologists, pathologists and others, and health authorities, can help to implement these methods and provide adequate resources. The recently available oral deferasirox can be used to conveniently administer iron chelation to transfusional iron-overloaded patients.

Advanced Q-switched DPSS lasers for ID-card marking

NASA Astrophysics Data System (ADS)

Hertwig, Michael; Paster, Martin; Terbrueggen, Ralf

2008-02-01

Increased homeland security concerns across the world have generated a strong demand for forgery-proof ID documents. Manufacturers currently employ a variety of high technology techniques to produce documents that are difficult to copy. However, production costs and lead times are still a concern when considering any possible manufacturing technology. Laser marking has already emerged as an important tool in the manufacturer's arsenal, and is currently being utilized to produce a variety of documents, such as plastic ID cards, drivers' licenses, health insurance cards and passports. The marks utilized can range from simple barcodes and text to high resolution, true grayscale images. The technical challenges posed by these marking tasks include delivering adequate mark legibility, minimizing substrate burning or charring, accurately reproducing grayscale data, and supporting the required process throughput. This article covers the advantages and basic requirements on laser marking of cards and reviews how laser output parameters affect marking quality, speed and overall process economics.

Backward Registration Based Aspect Ratio Similarity (ARS) for Image Retargeting Quality Assessment.

PubMed

Zhang, Yabin; Fang, Yuming; Lin, Weisi; Zhang, Xinfeng; Li, Leida

2016-06-28

During the past few years, there have been various kinds of content-aware image retargeting operators proposed for image resizing. However, the lack of effective objective retargeting quality assessment metrics limits the further development of image retargeting techniques. Different from traditional Image Quality Assessment (IQA) metrics, the quality degradation during image retargeting is caused by artificial retargeting modifications, and the difficulty for Image Retargeting Quality Assessment (IRQA) lies in the alternation of the image resolution and content, which makes it impossible to directly evaluate the quality degradation like traditional IQA. In this paper, we interpret the image retargeting in a unified framework of resampling grid generation and forward resampling. We show that the geometric change estimation is an efficient way to clarify the relationship between the images. We formulate the geometric change estimation as a Backward Registration problem with Markov Random Field (MRF) and provide an effective solution. The geometric change aims to provide the evidence about how the original image is resized into the target image. Under the guidance of the geometric change, we develop a novel Aspect Ratio Similarity metric (ARS) to evaluate the visual quality of retargeted images by exploiting the local block changes with a visual importance pooling strategy. Experimental results on the publicly available MIT RetargetMe and CUHK datasets demonstrate that the proposed ARS can predict more accurate visual quality of retargeted images compared with state-of-the-art IRQA metrics.

A probabilistic atlas of human brainstem pathways based on connectome imaging data.

PubMed

Tang, Yuchun; Sun, Wei; Toga, Arthur W; Ringman, John M; Shi, Yonggang

2018-04-01

The brainstem is a critical structure that regulates vital autonomic functions, houses the cranial nerves and their nuclei, relays motor and sensory information between the brain and spinal cord, and modulates cognition, mood, and emotions. As a primary relay center, the fiber pathways of the brainstem include efferent and afferent connections among the cerebral cortex, spinal cord, and cerebellum. While diffusion MRI has been successfully applied to map various brain pathways, its application for the in vivo imaging of the brainstem pathways has been limited due to inadequate resolution and large susceptibility-induced distortion artifacts. With the release of high-resolution data from the Human Connectome Project (HCP), there is increasing interest in mapping human brainstem pathways. Previous works relying on HCP data to study brainstem pathways, however, did not consider the prevalence (>80%) of large distortions in the brainstem even after the application of correction procedures from the HCP-Pipeline. They were also limited in the lack of adequate consideration of subject variability in either fiber pathways or region of interests (ROIs) used for bundle reconstruction. To overcome these limitations, we develop in this work a probabilistic atlas of 23 major brainstem bundles using high-quality HCP data passing rigorous quality control. For the large-scale data from the 500-Subject release of HCP, we conducted extensive quality controls to exclude subjects with severe distortions in the brainstem area. After that, we developed a systematic protocol to manually delineate 1300 ROIs on 20 HCP subjects (10 males; 10 females) for the reconstruction of fiber bundles using tractography techniques. Finally, we leveraged our novel connectome modeling techniques including high order fiber orientation distribution (FOD) reconstruction from multi-shell diffusion imaging and topography-preserving tract filtering algorithms to successfully reconstruct the 23 fiber bundles for each subject, which were then used to calculate the probabilistic atlases in the MNI152 space for public release. In our experimental results, we demonstrate that our method yielded anatomically faithful reconstruction of the brainstem pathways and achieved improved performance in comparison with an existing atlas of cerebellar peduncles based on HCP data. These atlases have been publicly released on NITRIC (https://www.nitrc.org/projects/brainstem_atlas/) and can be readily used by brain imaging researchers interested in studying brainstem pathways. Copyright © 2017 Elsevier Inc. All rights reserved.

Optimisation and establishment of diagnostic reference levels in paediatric plain radiography

NASA Astrophysics Data System (ADS)

Paulo, Graciano do Nascimento Nobre

Purpose: This study aimed to propose Diagnostic Reference Levels (DRLs) in paediatric plain radiography and to optimise the most frequent paediatric plain radiography examinations in Portugal following an analysis and evaluation of current practice. Methods and materials: Anthropometric data (weight, patient height and thickness of the irradiated anatomy) was collected from 9,935 patients referred for a radiography procedure to one of the three dedicated paediatric hospitals in Portugal. National DRLs were calculated for the three most frequent X-ray procedures at the three hospitals: chest AP/PA projection; abdomen AP projection; pelvis AP projection. Exposure factors and patient dose were collected prospectively at the clinical sites. In order to analyse the relationship between exposure factors, the use of technical features and dose, experimental tests were made using two anthropomorphic phantoms: a) CIRSTM ATOM model 705; height: 110cm, weight: 19kg and b) Kyoto kagakuTM model PBU-60; height: 165cm, weight: 50kg. After phantom data collection, an objective image analysis was performed by analysing the variation of the mean value of the standard deviation, measured with OsiriX software (Pixmeo, Switzerland). After proposing new exposure criteria, a Visual Grading Characteristic image quality evaluation was performed blindly by four paediatric radiologists, each with a minimum of 10 years of professional experience, using anatomical criteria scoring. Results: DRLs by patient weight groups have been established for the first time. ESAKP75 DRLs for both patient age and weight groups were also obtained and are described in the thesis. Significant dose reduction was achieved through the implementation of an optimisation programme: an average reduction of 41% and 18% on KAPP75 and ESAKP75, respectively for chest plain radiography; an average reduction of 58% and 53% on KAPP75 and ESAKP75, respectively for abdomen plain radiography; and an average reduction of 47% and 48% on KAPP75 and ESAKP75, respectively for pelvis plain radiography. Conclusion: Portuguese DRLs for plain radiography were obtained for paediatric plain radiography (chest AP/PA, abdomen and pelvis). Experimental phantom tests identified adequate plain radiography exposure criteria, validated by objective and subjective image quality analysis. The new exposure criteria were put into practice in one of the paediatric hospitals, by introducing an optimisation programme. The implementation of the optimisation programme allowed a significant dose reduction to paediatric patients, without compromising image quality. (Abstract shortened by ProQuest.).

Image quality assessment using deep convolutional networks

NASA Astrophysics Data System (ADS)

Li, Yezhou; Ye, Xiang; Li, Yong

2017-12-01

This paper proposes a method of accurately assessing image quality without a reference image by using a deep convolutional neural network. Existing training based methods usually utilize a compact set of linear filters for learning features of images captured by different sensors to assess their quality. These methods may not be able to learn the semantic features that are intimately related with the features used in human subject assessment. Observing this drawback, this work proposes training a deep convolutional neural network (CNN) with labelled images for image quality assessment. The ReLU in the CNN allows non-linear transformations for extracting high-level image features, providing a more reliable assessment of image quality than linear filters. To enable the neural network to take images of any arbitrary size as input, the spatial pyramid pooling (SPP) is introduced connecting the top convolutional layer and the fully-connected layer. In addition, the SPP makes the CNN robust to object deformations to a certain extent. The proposed method taking an image as input carries out an end-to-end learning process, and outputs the quality of the image. It is tested on public datasets. Experimental results show that it outperforms existing methods by a large margin and can accurately assess the image quality on images taken by different sensors of varying sizes.

Evaluation of technical quality and periapical health of root-filled teeth by using cone-beam CT

PubMed Central

Bilge Gülsüm, NUR; Evren, OK; ALTUNSOY, Mustafa; AĞLARCI, Osman Sami; ÇOLAK, Mehmet; GÜNGÖR, Enes

2014-01-01

Objective This study aimed to assess the quality of root fillings, coronal restorations, complications of all root-filled teeth and their association with apical periodontitis (AP) detected by cone-beam computed tomography (CBCT) images from an adult Turkish subpopulation. Material and Methods The sample for this study consisted of 242 patients (aging from 15 to 72 years) with 522 endodontically treated teeth that were assessed for technical quality of the root canal filling and periapical status of the teeth. Additionally, the apical status of each root-filled tooth was assessed according to the gender, dental arch, tooth type and age classification, undetected canals, instrument fracture, root fracture, apical resorption, apical lesion, furcation lesion and type and quality of the coronal structure. Statistical analysis was performed using percentages and chi-square test. Results The success rate of the root canal treatment was of 54.4%. The success rates of adequate and inadequate root canal treatment were not significantly different (p>0.05). Apical periodontitis was found in 228 (45.6%) teeth treated for root canals. Higher prevalence of AP was found in patients aging from 20 to 29 years [64 (27%) teeth] and in anterior (canines and incisors) teeth [97 (41%) teeth]. Conclusions The technical quality of root canal filling performed by dental practitioners in a Turkish subpopulation was consistent with a high prevalence of AP. The probable reasons for this failure are multifactorial, and there may be a need for improved undergraduate education and postgraduate courses to improve the clinical skills of dental practitioners in endodontics. PMID:25591019

The Radiologist Is in, but Was it Worth the Wait? Radiology Resident Note Quality in an Outpatient Interventional Radiology Clinic.

PubMed

Abboud, Salim E; Soriano, Stephanie; Abboud, Rayan; Patel, Indravadan; Davidson, Jon; Azar, Nami R; Nakamoto, Dean A

Preprocedural evaluation of patients in an interventional radiology (IR) clinic is a complex synthesis of physical examination and imaging findings, and as IR transitions to an independent clinical specialty, such evaluations will become an increasingly critical component of a successful IR practice and quality patient care. Prior research suggests that preprocedural evaluations increased patient's perceived quality of care and may improve procedural technical success rates. Appropriate documentation of a preprocedural evaluation in the medical record is also paramount for an interventional radiologist to add value and function as an effective member of a larger IR service and multidisciplinary health care team. The purpose of this study is to examine the quality of radiology resident notes for patients seen in an outpatient IR clinic at a single academic medical center before and after the adoption of clinic note template with reminders to include platelet count, international normalized ratio, glomerular filtration rate, and plan for periprocedural coagulation status. Before adoption of the template, platelet count, international normalized ratio, glomerular filtration rate and an appropriate plan for periprocedural coagulation status were documented in 72%, 82%, 42%, and 33% of patients, respectively. After adoption of the template, appropriate documentation of platelet count, international normalized ratio, and glomerular filtration rate increased to 96%, and appropriate plan for periprocedural coagulation status was documented in 83% of patients. Patient evaluation and clinical documentation skills may not be adequately practiced during radiology residency, and tools such as templates may help increase documentation quality by radiology residents. Copyright © 2017 Elsevier Inc. All rights reserved.

Impact of B-Scan Averaging on Spectralis Optical Coherence Tomography Image Quality before and after Cataract Surgery

PubMed Central

Podkowinski, Dominika; Sharian Varnousfaderani, Ehsan; Simader, Christian; Bogunovic, Hrvoje; Philip, Ana-Maria; Gerendas, Bianca S.

2017-01-01

Background and Objective To determine optimal image averaging settings for Spectralis optical coherence tomography (OCT) in patients with and without cataract. Study Design/Material and Methods In a prospective study, the eyes were imaged before and after cataract surgery using seven different image averaging settings. Image quality was quantitatively evaluated using signal-to-noise ratio, distinction between retinal layer image intensity distributions, and retinal layer segmentation performance. Measures were compared pre- and postoperatively across different degrees of averaging. Results 13 eyes of 13 patients were included and 1092 layer boundaries analyzed. Preoperatively, increasing image averaging led to a logarithmic growth in all image quality measures up to 96 frames. Postoperatively, increasing averaging beyond 16 images resulted in a plateau without further benefits to image quality. Averaging 16 frames postoperatively provided comparable image quality to 96 frames preoperatively. Conclusion In patients with clear media, averaging 16 images provided optimal signal quality. A further increase in averaging was only beneficial in the eyes with senile cataract. However, prolonged acquisition time and possible loss of details have to be taken into account. PMID:28630764

Echocardiography and cardiac resynchronisation therapy, friends or foes?

PubMed

van Everdingen, W M; Schipper, J C; van 't Sant, J; Ramdat Misier, K; Meine, M; Cramer, M J

2016-01-01

Echocardiography is used in cardiac resynchronisation therapy (CRT) to assess cardiac function, and in particular left ventricular (LV) volumetric status, and prediction of response. Despite its widespread applicability, LV volumes determined by echocardiography have inherent measurement errors, interobserver and intraobserver variability, and discrepancies with the gold standard magnetic resonance imaging. Echocardiographic predictors of CRT response are based on mechanical dyssynchrony. However, parameters are mainly tested in single-centre studies or lack feasibility. Speckle tracking echocardiography can guide LV lead placement, improving volumetric response and clinical outcome by guiding lead positioning towards the latest contracting segment. Results on optimisation of CRT device settings using echocardiographic indices have so far been rather disappointing, as results suffer from noise. Defining response by echocardiography seems valid, although re-assessment after 6 months is advisable, as patients can show both continuous improvement as well as deterioration after the initial response. Three-dimensional echocardiography is interesting for future implications, as it can determine volume, dyssynchrony and viability in a single recording, although image quality needs to be adequate. Deformation patterns from the septum and the derived parameters are promising, although validation in a multicentre trial is required. We conclude that echocardiography has a pivotal role in CRT, although clinicians should know its shortcomings.

Scientific Design of the New Neutron Radiography Facility (SANRAD) at SAFARI-1 for South Africa

NASA Astrophysics Data System (ADS)

de Beer, F. C.; Gruenauer, F.; Radebe, J. M.; Modise, T.; Schillinger, B.

The final scientific design for an upgraded neutron radiography/tomography facility at beam port no.2 of the SAFARI-1 nuclear research reactor has been performed through expert advice from Physics Consulting, FRMII in Germany and IPEN, Brazil. A need to upgrade the facility became apparent due to the identification of various deficiencies of the current SANRAD facility during an IAEA-sponsored expert mission of international scientists to Necsa, South Africa. A lack of adequate shielding that results in high neutron background on the beam port floor, a mismatch in the collimator aperture to the core that results in a high gradient in neutron flux on the imaging plane and due to a relative low L/D the quality of the radiographs are poor, are a number of deficiencies to name a few.The new design, based on results of Monte Carlo (MCNP-X) simulations of neutron- and gamma transport from the reactor core and through the new facility, is being outlined. The scientific design philosophy, neutron optics and imaging capabilities that include the utilization of fission neutrons, thermal neutrons, and gamma-rays emerging from the core of SAFARI-1 are discussed.

Multislice spiral CT simulator for dynamic cardiopulmonary studies

NASA Astrophysics Data System (ADS)

De Francesco, Silvia; Ferreira da Silva, Augusto M.

2002-04-01

We've developed a Multi-slice Spiral CT Simulator modeling the acquisition process of a real tomograph over a 4-dimensional phantom (4D MCAT) of the human thorax. The simulator allows us to visually characterize artifacts due to insufficient temporal sampling and a priori evaluate the quality of the images obtained in cardio-pulmonary studies (both with single-/multi-slice and ECG gated acquisition processes). The simulating environment allows both for conventional and spiral scanning modes and includes a model of noise in the acquisition process. In case of spiral scanning, reconstruction facilities include longitudinal interpolation methods (360LI and 180LI both for single and multi-slice). Then, the reconstruction of the section is performed through FBP. The reconstructed images/volumes are affected by distortion due to insufficient temporal sampling of the moving object. The developed simulating environment allows us to investigate the nature of the distortion characterizing it qualitatively and quantitatively (using, for example, Herman's measures). Much of our work is focused on the determination of adequate temporal sampling and sinogram regularization techniques. At the moment, the simulator model is limited to the case of multi-slice tomograph, being planned as a next step of development the extension to cone beam or area detectors.

Using seemingly unnecessary illustrations to improve the diagnostic usefulness of descriptions in taxonomy–a case study on Perochaeta orientalis (Diptera, Sepsidae)

PubMed Central

Ang, Yuchen; Wong, Ling Jing; Meier, Rudolf

2013-01-01

Abstract Many species descriptions, especially older ones, consist mostly of text and have few illustrations. Only the most conspicuous morphological features needed for species diagnosis and delimitation at the time of description are illustrated. Such descriptions can quickly become inadequate when new species or characters are discovered. We propose that descriptions should become more data-rich by presenting a large amount of images and illustrations to cover as much morphology as possible; these descriptions are more likely to remain adequate over time because their large amounts of visual data could capture character systems that may become important in the future. Such an approach can now be quickly and easily achieved given that high-quality digital photography is readily available. Here, we re-describe the sepsid fly Perochaeta orientalis (de Meijere 1913) (Diptera, Sepsidae) which has suffered from inadequate descriptions in the past, and use photomicrography, scanning electron microscopy and videography to document its external morphology and mating behaviour. All images and videos are embedded within the electronic publication. We discuss briefly benefits and problems with our approach. PMID:24363567

Management of thyroid cytological material, pre-analytical procedures and bio-banking.

PubMed

Bode-Lesniewska, Beata; Cochand-Priollet, Beatrix; Straccia, Patrizia; Fadda, Guido; Bongiovanni, Massimo

2018-06-09

Thyroid nodules are common and increasingly detected due to recent advances in imaging techniques. However, clinically relevant thyroid cancer is rare and the mortality from aggressive thyroid cancer remains constant. FNAC (Fine Needle Aspiration Cytology) is a standard method for diagnosing thyroid malignancy and the discrimination of malignant nodules from goiter. As the examined nodules on thyroid FNAC are often small incidental findings, it is important to maintain a low rate of undetermined diagnoses requiring further clinical work up or surgery. The most important factors determining the accuracy of the cytological diagnosis and suitability for biobanking of thyroid FNACs are the quality of the sample and availability of adequate tissue for auxiliary studies. This article analyses technical aspects (pre-analytics) of performing thyroid FNACs, including image guidance and rapid on slide evaluation (ROSE), sample collection methods (conventional slides, liquid based methods (LBC), cell blocks) and storage (bio-banking). The spectrum of the special studies (immunocytochemistry on direct slides or LBC, immunohistochemistry on cell blocks and molecular methods) required for improving the precision of the cytological diagnosis of the thyroid nodules is discussed. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Videofluorographic assessment of deglutitive behaviors in a rat model of aging and Parkinson disease.

PubMed

Russell, John A; Ciucci, Michelle R; Hammer, Michael J; Connor, Nadine P

2013-03-01

Dysphagia is commonly associated with aging and Parkinson disease and can have a significant impact on a person's quality of life. In some cases, dysphagia may be life-threatening. Animal models may be used to study underlying mechanisms of dysphagia, but paradigms that allow adequate imaging of the swallow in combination with measurement of physiological variables have not been forthcoming. To begin development of methods that allow this, we used videofluorography to record the deglutition behaviors of 22 Fisher 344/Brown Norway rats in young adult (9 months old), old (32 months old), and parkinsonian (unilateral lesion to the medial forebrain bundle) groups. We hypothesized that the old and parkinsonian rats would manifest deficits in deglutition behaviors analogous to those found in human clinical populations. Our results supported our hypothesis in that the old group demonstrated reductions in bolus transport speeds and mastication rate while the parkinsonian rats showed impairments in oral processing. Interpretation of these results should consider the particular animal model, lesion type, and videofluorographic protocol used in this work. Future studies will link swallow imaging data of this kind with physiological and anatomical data in a manner not possible with human participants.

Videofluorographic assessment of deglutitive behaviors in a rat model of aging and Parkinson disease

PubMed Central

Russell, John A.; Ciucci, Michelle R.; Hammer, Michael J.; Connor, Nadine P.

2012-01-01

Dysphagia is commonly associated with aging and Parkinson disease and can have a significant impact on a person’s quality of life. In some cases, dysphagia may be life threatening. Animal models may be used to study underlying mechanisms of dysphagia, but paradigms that allow adequate imaging of the swallow in combination with measurement of physiological variables have not been forthcoming. To begin development of methods that allow this, we used videofluorography to record the deglutition behaviors of 22 Fischer 344-Brown Norway rats in young adult (9 months old), old (32 months old), and parkinsonian (unilateral lesion to the medial forebrain bundle) groups. We hypothesized that the old and parkinsonian rats would manifest deficits in deglutition behaviors analogous to those found in human clinical populations. Our results supported our hypotheses in that the old group demonstrated reductions in bolus transport speeds and mastication rate, while the parkinsonian rats showed impairments in oral processing. Interpretation of these results should consider the particular animal model, lesion type and videoflurographic protocol used in this work. Future studies will link swallow imaging data of this kind with physiological and anatomical data in a manner not possible with human participants. PMID:22763806

Micro*scope: a new internet resources for microbiology teaching

NASA Astrophysics Data System (ADS)

Patterson, D. J.; Sogin, M. L.

Micro-organisms are major players in all natural ecosystems, have dominated the Earth's biosphere for most of its existence, and have determined the character of the habitable planet. Yet a lack of adequate educational resources hinders the appreciation of microbial diversity and ecology. micro*scope is a new internet initiative which aims to provide resources to students and teachers. The site has five major domains. Classification: A comprehensive hierarchical classification of all prokaryotes and protists to the level of genus. The classification is used to navigate to further information. UbIO sofware new software for the management of names and classification schemes, allowing all known names for the same organisms to be mapped against each other so maximize the recovery of information. Images: about 3500 images are available, with high quality versions available to be downloaded. Outward internet links, the web site prompts the user to explore more authoritative or specialist sites to find further information on any species or taxon being visited. Educational resources, we include simple to use Lucid guides to help students and scientists identify micro-organisms are available through the internet. Other resources are also being assembled. The site is still under development.

Use of focus measure operators for characterization of flood illumination adaptive optics ophthalmoscopy image quality

PubMed Central

Alonso-Caneiro, David; Sampson, Danuta M.; Chew, Avenell L.; Collins, Michael J.; Chen, Fred K.

2018-01-01

Adaptive optics flood illumination ophthalmoscopy (AO-FIO) allows imaging of the cone photoreceptor in the living human retina. However, clinical interpretation of the AO-FIO image remains challenging due to suboptimal quality arising from residual uncorrected wavefront aberrations and rapid eye motion. An objective method of assessing image quality is necessary to determine whether an AO-FIO image is suitable for grading and diagnostic purpose. In this work, we explore the use of focus measure operators as a surrogate measure of AO-FIO image quality. A set of operators are tested on data sets acquired at different focal depths and different retinal locations from healthy volunteers. Our results demonstrate differences in focus measure operator performance in quantifying AO-FIO image quality. Further, we discuss the potential application of the selected focus operators in (i) selection of the best quality AO-FIO image from a series of images collected at the same retinal location and (ii) assessment of longitudinal changes in the diseased retina. Focus function could be incorporated into real-time AO-FIO image processing and provide an initial automated quality assessment during image acquisition or reading center grading. PMID:29552404

Gradient Magnitude Similarity Deviation: A Highly Efficient Perceptual Image Quality Index.

PubMed

Xue, Wufeng; Zhang, Lei; Mou, Xuanqin; Bovik, Alan C

2014-02-01

It is an important task to faithfully evaluate the perceptual quality of output images in many applications, such as image compression, image restoration, and multimedia streaming. A good image quality assessment (IQA) model should not only deliver high quality prediction accuracy, but also be computationally efficient. The efficiency of IQA metrics is becoming particularly important due to the increasing proliferation of high-volume visual data in high-speed networks. We present a new effective and efficient IQA model, called gradient magnitude similarity deviation (GMSD). The image gradients are sensitive to image distortions, while different local structures in a distorted image suffer different degrees of degradations. This motivates us to explore the use of global variation of gradient based local quality map for overall image quality prediction. We find that the pixel-wise gradient magnitude similarity (GMS) between the reference and distorted images combined with a novel pooling strategy-the standard deviation of the GMS map-can predict accurately perceptual image quality. The resulting GMSD algorithm is much faster than most state-of-the-art IQA methods, and delivers highly competitive prediction accuracy. MATLAB source code of GMSD can be downloaded at http://www4.comp.polyu.edu.hk/~cslzhang/IQA/GMSD/GMSD.htm.

Use of focus measure operators for characterization of flood illumination adaptive optics ophthalmoscopy image quality.

PubMed

Alonso-Caneiro, David; Sampson, Danuta M; Chew, Avenell L; Collins, Michael J; Chen, Fred K

2018-02-01

Adaptive optics flood illumination ophthalmoscopy (AO-FIO) allows imaging of the cone photoreceptor in the living human retina. However, clinical interpretation of the AO-FIO image remains challenging due to suboptimal quality arising from residual uncorrected wavefront aberrations and rapid eye motion. An objective method of assessing image quality is necessary to determine whether an AO-FIO image is suitable for grading and diagnostic purpose. In this work, we explore the use of focus measure operators as a surrogate measure of AO-FIO image quality. A set of operators are tested on data sets acquired at different focal depths and different retinal locations from healthy volunteers. Our results demonstrate differences in focus measure operator performance in quantifying AO-FIO image quality. Further, we discuss the potential application of the selected focus operators in (i) selection of the best quality AO-FIO image from a series of images collected at the same retinal location and (ii) assessment of longitudinal changes in the diseased retina. Focus function could be incorporated into real-time AO-FIO image processing and provide an initial automated quality assessment during image acquisition or reading center grading.

Comprehensive model for predicting perceptual image quality of smart mobile devices.

PubMed

Gong, Rui; Xu, Haisong; Luo, M R; Li, Haifeng

2015-01-01

An image quality model for smart mobile devices was proposed based on visual assessments of several image quality attributes. A series of psychophysical experiments were carried out on two kinds of smart mobile devices, i.e., smart phones and tablet computers, in which naturalness, colorfulness, brightness, contrast, sharpness, clearness, and overall image quality were visually evaluated under three lighting environments via categorical judgment method for various application types of test images. On the basis of Pearson correlation coefficients and factor analysis, the overall image quality could first be predicted by its two constituent attributes with multiple linear regression functions for different types of images, respectively, and then the mathematical expressions were built to link the constituent image quality attributes with the physical parameters of smart mobile devices and image appearance factors. The procedure and algorithms were applicable to various smart mobile devices, different lighting conditions, and multiple types of images, and performance was verified by the visual data.

Proceedings of the Augmented VIsual Display (AVID) Research Workshop

NASA Technical Reports Server (NTRS)

Kaiser, Mary K. (Editor); Sweet, Barbara T. (Editor)

1993-01-01

The papers, abstracts, and presentations were presented at a three day workshop focused on sensor modeling and simulation, and image enhancement, processing, and fusion. The technical sessions emphasized how sensor technology can be used to create visual imagery adequate for aircraft control and operations. Participants from industry, government, and academic laboratories contributed to panels on Sensor Systems, Sensor Modeling, Sensor Fusion, Image Processing (Computer and Human Vision), and Image Evaluation and Metrics.

Image Quality Performance Measurement of the microPET Focus 120

NASA Astrophysics Data System (ADS)

Ballado, Fernando Trejo; López, Nayelli Ortega; Flores, Rafael Ojeda; Ávila-Rodríguez, Miguel A.

2010-12-01

The aim of this work is to evaluate the characteristics involved in the image reconstruction of the microPET Focus 120. For this evaluation were used two different phantoms; a miniature hot-rod Derenzo phantom and a National Electrical Manufacturers Association (NEMA) NU4-2008 image quality (IQ) phantom. The best image quality was obtained when using OSEM3D as the reconstruction method reaching a spatial resolution of 1.5 mm with the Derenzo phantom filled with 18F. Image quality test results indicate a superior image quality for the Focus 120 when compared to previous microPET models.

Sedation/anaesthesia in paediatric radiology

PubMed Central

Arlachov, Y; Ganatra, R H

2012-01-01

Objectives In this article we will give a comprehensive literature review on sedation/general anaesthesia (S/GA) and discuss the international variations in practice and options available for S/GA for imaging children. Methods The key articles were obtained primarily from PubMed, MEDLINE, ERIC, NHS Evidence and The Cochrane Library. Results Recently, paediatric radiology has seen a surge of diagnostic and therapeutic procedures, some of which require children to be still and compliant for up to 1 h. It is difficult and sometimes even impossible to obtain quick and high-quality images without employing sedating techniques in certain children. As with any medical procedure, S/GA in radiological practice is not without risks and can have potentially disastrous consequences if mismanaged. In order to reduce any complications and practice safety in radiological units, it is imperative to carry out pre-sedation assessments of children, obtain parental/guardian consent, monitor them closely before, during and after the procedure and have adequate equipment, a safe environment and a well-trained personnel. Conclusion Although the S/GA techniques, sedative drugs and personnel involved vary from country to country, the ultimate goal of S/GA in radiology remains the same; namely, to provide safety and comfort for the patients. Advances in knowledge Imaging children under general anaesthesia is becoming routine and preferred by operators because it ensures patient conformity and provides a more controlled environment. PMID:22898157

An MRI-Compatible High Frequency AC Resistive Heating System for Homeothermic Maintenance in Small Animals

PubMed Central

Gomes, Ana L.; Kinchesh, Paul; Kersemans, Veerle; Allen, Philip D.; Smart, Sean C.

2016-01-01

Purpose To develop an MRI-compatible resistive heater, using high frequency alternating current (AC), for temperature maintenance of anaesthetised animals. Materials and Methods An MRI-compatible resistive electrical heater was formed from narrow gauge wire connected to a high frequency (10–100 kHz) AC power source. Multiple gradient echo images covering a range of echo times, and pulse-acquire spectra were acquired with the wire heater powered using high frequency AC or DC power sources and without any current flowing in order to assess the sensitivity of the MRI acquisitions to the presence of current flow through the heater wire. The efficacy of temperature maintenance using the AC heater was assessed by measuring rectal temperature immediately following induction of general anaesthesia for a period of 30 minutes in three different mice. Results Images and spectra acquired in the presence and absence of 50–100 kHz AC through the wire heater were indistinguishable, whereas DC power created field shifts and lineshape distortions. Temperature lost during induction of anaesthesia was recovered within approximately 20 minutes and a stable temperature was reached as the mouse’s temperature approached the set target. Conclusion The AC-powered wire heater maintains adequate heat input to the animal to maintain body temperature, and does not compromise image quality. PMID:27806062

The Use of Mouse Models of Breast Cancer and Quantitative Image Analysis to Evaluate Hormone Receptor Antigenicity after Microwave-assisted Formalin Fixation

PubMed Central

Engelberg, Jesse A.; Giberson, Richard T.; Young, Lawrence J.T.; Hubbard, Neil E.

2014-01-01

Microwave methods of fixation can dramatically shorten fixation times while preserving tissue structure; however, it remains unclear if adequate tissue antigenicity is preserved. To assess and validate antigenicity, robust quantitative methods and animal disease models are needed. We used two mouse mammary models of human breast cancer to evaluate microwave-assisted and standard 24-hr formalin fixation. The mouse models expressed four antigens prognostic for breast cancer outcome: estrogen receptor, progesterone receptor, Ki67, and human epidermal growth factor receptor 2. Using pathologist evaluation and novel methods of quantitative image analysis, we measured and compared the quality of antigen preservation, percentage of positive cells, and line plots of cell intensity. Visual evaluations by pathologists established that the amounts and patterns of staining were similar in tissues fixed by the different methods. The results of the quantitative image analysis provided a fine-grained evaluation, demonstrating that tissue antigenicity is preserved in tissues fixed using microwave methods. Evaluation of the results demonstrated that a 1-hr, 150-W fixation is better than a 45-min, 150-W fixation followed by a 15-min, 650-W fixation. The results demonstrated that microwave-assisted formalin fixation can standardize fixation times to 1 hr and produce immunohistochemistry that is in every way commensurate with longer conventional fixation methods. PMID:24682322

Quantity versus Quality in Turkish Higher Education.

ERIC Educational Resources Information Center

Arslan, Hasan

This paper asserts that there have not been adequate studies about the comparative quality of Turkish universities to provide information and data for prospective students, advisors, university administrators, and policymakers. Turkey has more than 70 state and private universities. Most of these are relatively new, although Turkish higher…

Characterization of Mineral Nutrients in National Plant Germplasm System (NPGS) Tomato Varieties

USDA-ARS?s Scientific Manuscript database

Tomato (Solanum lycopersicum) fruit quality and yield are highly dependent on adequate uptake of nutrients. Potassium, magnesium and calcium are essential elements that influence fruit quality traits such as color, uniformity of ripening, hollow fruit, fruit shape, firmness, and acidity. Sodium is...

Environmental Inventory Report. East St. Louis and Vicinity, Cahokia Canal Drainage Area, Madison and St. Clair Counties, Illinois. Volume 2.

DTIC Science & Technology

1981-05-01

of air quality which the Administrator judges are necessary to protect the public health with an adequate * margin of safety...National secondary ambient air quality standards define levels of air quality which the Admini- strator judges necessary to protect the public welfare...steps to meet Illinois Environmental Protection Agency (IEPA) emission and air quality standards through- out the 1970s. The

Image quality assessment metric for frame accumulated image

NASA Astrophysics Data System (ADS)

Yu, Jianping; Li, Gang; Wang, Shaohui; Lin, Ling

2018-01-01

The medical image quality determines the accuracy of diagnosis, and the gray-scale resolution is an important parameter to measure image quality. But current objective metrics are not very suitable for assessing medical images obtained by frame accumulation technology. Little attention was paid to the gray-scale resolution, basically based on spatial resolution and limited to the 256 level gray scale of the existing display device. Thus, this paper proposes a metric, "mean signal-to-noise ratio" (MSNR) based on signal-to-noise in order to be more reasonable to evaluate frame accumulated medical image quality. We demonstrate its potential application through a series of images under a constant illumination signal. Here, the mean image of enough images was regarded as the reference image. Several groups of images by different frame accumulation and their MSNR were calculated. The results of the experiment show that, compared with other quality assessment methods, the metric is simpler, more effective, and more suitable for assessing frame accumulated images that surpass the gray scale and precision of the original image.

Synthesized view comparison method for no-reference 3D image quality assessment

NASA Astrophysics Data System (ADS)

Luo, Fangzhou; Lin, Chaoyi; Gu, Xiaodong; Ma, Xiaojun

2018-04-01

We develop a no-reference image quality assessment metric to evaluate the quality of synthesized view rendered from the Multi-view Video plus Depth (MVD) format. Our metric is named Synthesized View Comparison (SVC), which is designed for real-time quality monitoring at the receiver side in a 3D-TV system. The metric utilizes the virtual views in the middle which are warped from left and right views by Depth-image-based rendering algorithm (DIBR), and compares the difference between the virtual views rendered from different cameras by Structural SIMilarity (SSIM), a popular 2D full-reference image quality assessment metric. The experimental results indicate that our no-reference quality assessment metric for the synthesized images has competitive prediction performance compared with some classic full-reference image quality assessment metrics.

Deep supervised dictionary learning for no-reference image quality assessment

NASA Astrophysics Data System (ADS)

Huang, Yuge; Liu, Xuesong; Tian, Xiang; Zhou, Fan; Chen, Yaowu; Jiang, Rongxin

2018-03-01

We propose a deep convolutional neural network (CNN) for general no-reference image quality assessment (NR-IQA), i.e., accurate prediction of image quality without a reference image. The proposed model consists of three components such as a local feature extractor that is a fully CNN, an encoding module with an inherent dictionary that aggregates local features to output a fixed-length global quality-aware image representation, and a regression module that maps the representation to an image quality score. Our model can be trained in an end-to-end manner, and all of the parameters, including the weights of the convolutional layers, the dictionary, and the regression weights, are simultaneously learned from the loss function. In addition, the model can predict quality scores for input images of arbitrary sizes in a single step. We tested our method on commonly used image quality databases and showed that its performance is comparable with that of state-of-the-art general-purpose NR-IQA algorithms.