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Sample records for response imaging evaluation

  1. Computerized PET/CT image analysis in the evaluation of tumour response to therapy

    PubMed Central

    Wang, J; Zhang, H H

    2015-01-01

    Current cancer therapy strategy is mostly population based, however, there are large differences in tumour response among patients. It is therefore important for treating physicians to know individual tumour response. In recent years, many studies proposed the use of computerized positron emission tomography/CT image analysis in the evaluation of tumour response. Results showed that computerized analysis overcame some major limitations of current qualitative and semiquantitative analysis and led to improved accuracy. In this review, we summarize these studies in four steps of the analysis: image registration, tumour segmentation, image feature extraction and response evaluation. Future works are proposed and challenges described. PMID:25723599

  2. Digital Image Analysis for Morphometric Evaluation of Tissue Response after Implanting Alloplastic Vascular Prostheses

    NASA Astrophysics Data System (ADS)

    Zippel, Roland; Hoene, Andreas; Walschus, Uwe; Jarchow, Raymond; Ueberrueck, Torsten; Patrzyk, Maciej; Schlosser, Michael; Wilhelm, Lutz

    2006-07-01

    The aim of this study was to examine the suitability of digital image analysis, using the KS400 software system, for the morphometric evaluation of the tissue response after prosthesis implantation in an animal model. Twenty-four female pigs aged 10 weeks were implanted with infrarenal Dacron® prostheses for 14, 21, 28, and 116 days. Following the explantation and investigation of the neointima region, the expression of beta-1-integrin, the proliferation rate by means of Ki-67 positive cells, and the intima thickness were evaluated as exemplary parameters of the tissue response after implantation. Frozen tissue sections were immunohistochemically stained and subsequently examined using computer-aided image analysis. A maximum expression of 32.9% was observed for beta-1-integrin 14 days after implantation, gradually declining over time to 9.8% after 116 days. The proliferation rate was found to be 19% on day 14, increasing to 39% on day 21 with a subsequent gradual decline to 5% after 116 days. The intima thickness increased from 189.9 [mu]m on day 14 to 1228.0 [mu]m on day 116. In conclusion, digital image analysis was found to be an efficient and reproducible method for the morphometric evaluation of a peri-prosthetic tissue response.

  3. Application of spatial frequency response as a criterion for evaluating thermal imaging camera performance

    NASA Astrophysics Data System (ADS)

    Lock, Andrew; Amon, Francine

    2008-04-01

    Police, firefighters, and emergency medical personnel are examples of first responders that are utilizing thermal imaging cameras in a very practical way every day. However, few performance metrics have been developed to assist first responders in evaluating the performance of thermal imaging technology. This paper describes one possible metric for evaluating spatial resolution using an application of Spatial Frequency Response (SFR) calculations for thermal imaging. According to ISO 12233, the SFR is defined as the integrated area below the Modulation Transfer Function (MTF) curve derived from the discrete Fourier transform of a camera image representing a knife-edge target. This concept is modified slightly for use as a quantitative analysis of the camera's performance by integrating the area between the MTF curve and the camera's characteristic nonuniformity, or noise floor, determined at room temperature. The resulting value, which is termed the Effective SFR, can then be compared with a spatial resolution value obtained from human perception testing of task specific situations to determine the acceptability of the performance of thermal imaging cameras. The testing procedures described herein are being developed as part of a suite of tests for possible inclusion into a performance standard on thermal imaging cameras for first responders.

  4. A framework for the analysis and evaluation of optical imaging systems with arbitrary response functions

    NASA Astrophysics Data System (ADS)

    Wang, Zhipeng

    The scientific applications and engineering aspects of multispectral and hyperspectral imaging systems have been studied extensively. The traditional geometric spectral imaging system model is specifically developed aiming at spectral sensors with spectrally non-overlapping bands. Spectral imaging systems with overlapping bands also exist. For example, the quantum-dot infrared photodetectors (QDIPs) for midwave- and longwave-infrared (IR) imaging systems exhibit highly overlapping spectral responses tunable through the bias voltages applied. This makes it possible to build spectrally tunable imaging system in IR range based on single QDIP. Furthermore, the QDIP based system can be operated as being adaptive to scenes. Other optical imaging systems like the human eye and some polarimetric sensing systems also have overlapping bands. To analyze such sensors, a functional analysis-based framework is provided in this dissertation. The framework starts from the mathematical description of the interaction between sensor and the radiation from scene reaching it. A geometric model of the spectral imaging process is provided based on the framework. The spectral response functions and the scene spectra are considered as vectors inside an 1-dimensional spectral space. The spectral imaging process is abstracted to represent a projection of scene spectrum onto sensor. The projected spectrum, which is the least-square error reconstruction of the scene vectors, contains the useful information for image processing. Spectral sensors with arbitrary spectral response functions are can be analyzed with this model. The framework leads directly to an image pre-processing algorithm to remove the data correlation between bands. Further discussion shows that this model can also serve the purpose of sensor evaluation, and thus facilitates comparison between different sensors. The spectral shapes and the Signal-to-Noise Ratios (SNR) of different bands are seen to influence the sensor

  5. Vibration Response Imaging: evaluation of rater agreement in healthy subjects and subjects with pneumonia

    PubMed Central

    2010-01-01

    Background We evaluated pulmonologists variability in the interpretation of Vibration response imaging (VRI) obtained from healthy subjects and patients hospitalized for community acquired pneumonia. Methods The present is a prospective study conducted in a tertiary university hospital. Twenty healthy subjects and twenty three pneumonia cases were included in this study. Six pulmonologists blindly analyzed images of normal subjects and pneumonia cases and evaluated different aspects of VRI images related to the quality of data aquisition, synchronization of the progression of breath sound distribution and agreement between the maximal energy frame (MEF) of VRI (which is the maximal geographical area of lung vibrations produced at maximal inspiration) and chest radiography. For qualitative assessment of VRI images, the raters' evaluations were analyzed by degree of consistency and agreement. Results The average value for overall identical evaluations of twelve features of the VRI image evaluation, ranged from 87% to 95% per rater (94% to 97% in control cases and from 79% to 93% per rater in pneumonia cases). Inter-rater median (IQR) agreement was 91% (82-96). The level of agreement according to VRI feature evaluated was in most cases over 80%; intra-class correlation (ICC) obtained by using a model of subject/rater for the averaged features was overall 0.86 (0.92 in normal and 0.73 in pneumonia cases). Conclusions Our findings suggest good agreement in the interpretation of VRI data between different raters. In this respect, VRI might be helpful as a radiation free diagnostic tool for the management of pneumonia. PMID:20222975

  6. Imaging of Gastrointestinal Stromal Tumors: From Diagnosis to Evaluation of Therapeutic Response.

    PubMed

    Vernuccio, Federica; Taibbi, Adele; Picone, Dario; LA Grutta, Ludovico; Midiri, Massimo; Lagalla, Roberto; Lo Re, Giuseppe; Bartolotta, Tommaso Vincenzo

    2016-06-01

    Once considered an obscure tumor entity with poor prognosis, gastrointestinal stromal tumors (GISTs) are nowadays recognized as the most common mesenchymal tumors of the alimentary tract. GISTs differ from other mesenchymal neoplasms at pathology since 90% of them exhibit strong immunohistochemical staining for KIT, a tyrosinase kinase growth factor receptor. In the early 2000s, the ability of imatinib mesylate, a tyrosine kinase inhibitor, to inhibit KIT established a new paradigm for cancer treatment. A reduction in lesion size may not be observed or may appear many months after therapy; thus, tumor response criteria alternative to the Response Evaluation Criteria in Solid Tumors were developed. This review highlights the role of imaging in the detection, characterization, preoperative staging, postoperative assessment, therapy-response evaluation and treatment-related toxicities. All this information is crucial in optimizing patient management. Contrast-enhanced computed tomography is the most commonly used modality for staging the disease and assessing treatment response, whereas positron-emission tomography adds valuable functional information. Magnetic resonance imaging (MRI) may also be useful, especially in ano-rectal GISTs. Diffusion-weighted MRI may provide promising indicators of tumor response to targeted molecular therapy. Radiologists and oncologists should be aware of all these issues related to GISTs, since multidisciplinary teams gathering different expertise are usually needed to properly treat patients with GISTs. PMID:27272772

  7. Magnetic Resonance Imaging and Other Imaging Modalities in Diagnostic and Tumor Response Evaluation.

    PubMed

    Lambregts, Doenja M J; Maas, Monique; Stokkel, Marcel P M; Beets-Tan, Regina G H

    2016-07-01

    Functional imaging is emerging as a valuable contributor to the clinical management of patients with rectal cancer. Techniques such as diffusion-weighted magnetic resonance imaging, perfusion imaging, and positron emission tomography can offer meaningful insights into tissue architecture, vascularity, and metabolism. Moreover, new techniques targeting other aspects of tumor biology are now being developed and studied. This study reviews the potential role of functional imaging for the diagnosis, treatment monitoring, and assessment of prognosis in patients with rectal cancer. PMID:27238470

  8. Evaluation of chemotherapy response in ovarian cancer treatment using quantitative CT image biomarkers: a preliminary study

    NASA Astrophysics Data System (ADS)

    Qiu, Yuchen; Tan, Maxine; McMeekin, Scott; Thai, Theresa; Moore, Kathleen; Ding, Kai; Liu, Hong; Zheng, Bin

    2015-03-01

    The purpose of this study is to identify and apply quantitative image biomarkers for early prediction of the tumor response to the chemotherapy among the ovarian cancer patients participated in the clinical trials of testing new drugs. In the experiment, we retrospectively selected 30 cases from the patients who participated in Phase I clinical trials of new drug or drug agents for ovarian cancer treatment. Each case is composed of two sets of CT images acquired pre- and post-treatment (4-6 weeks after starting treatment). A computer-aided detection (CAD) scheme was developed to extract and analyze the quantitative image features of the metastatic tumors previously tracked by the radiologists using the standard Response Evaluation Criteria in Solid Tumors (RECIST) guideline. The CAD scheme first segmented 3-D tumor volumes from the background using a hybrid tumor segmentation scheme. Then, for each segmented tumor, CAD computed three quantitative image features including the change of tumor volume, tumor CT number (density) and density variance. The feature changes were calculated between the matched tumors tracked on the CT images acquired pre- and post-treatments. Finally, CAD predicted patient's 6-month progression-free survival (PFS) using a decision-tree based classifier. The performance of the CAD scheme was compared with the RECIST category. The result shows that the CAD scheme achieved a prediction accuracy of 76.7% (23/30 cases) with a Kappa coefficient of 0.493, which is significantly higher than the performance of RECIST prediction with a prediction accuracy and Kappa coefficient of 60% (17/30) and 0.062, respectively. This study demonstrated the feasibility of analyzing quantitative image features to improve the early predicting accuracy of the tumor response to the new testing drugs or therapeutic methods for the ovarian cancer patients.

  9. Importance of assessing nonattenuation-corrected positron emission tomography images in treatment response evaluation of primary cutaneous lymphoma

    PubMed Central

    Chandra, Piyush; Agrawal, Archi; Purandare, Nilendu; Shah, Sneha; Rangarajan, Venkatesh

    2016-01-01

    Studies have shown previously that nonattenuated corrected (AC) positron emission tomography (PET) images improve detection of superficial lesions when compared to AC images. We present a case of cutaneous lymphoma to demonstrate the importance of assessing nonattenuation-corrected PET images in treatment response evaluation. PMID:27385905

  10. IMAGE-GUIDED EVALUATION AND MONITORING OF TREATMENT RESPONSE IN PATIENTS WITH DRY EYE DISEASE

    PubMed Central

    Hamrah, Pedram

    2014-01-01

    Dry eye disease (DED) is one of the most common ocular disorders worldwide. The pathophysiological mechanisms involved in the development of DED are not well understood and thus treating DED has been a significant challenge for ophthalmologists. Most of the currently available diagnostic tests demonstrate low correlation to patient symptoms and have low reproducibility. Recently, sophisticated in vivo imaging modalities have become available for patient care, namely, in vivo confocal microscopy (IVCM) and optical coherence tomography (OCT). These emerging modalities are powerful and non-invasive, allowing real-time visualization of cellular and anatomical structures of the cornea and ocular surface. Here we discuss how, by providing both qualitative and quantitative assessment, these techniques can be used to demonstrate early subclinical disease, grade layer-by-layer severity, and allow monitoring of disease severity by cellular alterations. Imaging-guided stratification of patients may also be possible in conjunction with clinical examination methods. Visualization of subclinical changes and stratification of patients in vivo, allows objective image-guided evaluation of tailored treatment response based on cellular morphological alterations specific to each patient. This image-guided approach to DED may ultimately improve patient outcomes and allow studying the efficacy of novel therapies in clinical trials. PMID:24696045

  11. SU-E-QI-20: A Review of Advanced PET and CT Image Features for the Evaluation of Tumor Response

    SciTech Connect

    Lu, W

    2014-06-15

    Purpose: To review the literature in using quantitative PET and CT image features for the evaluation of tumor response. Methods: We reviewed and summarized more than fifty papers that use advanced, quantitative PET/CT image features for the evaluation of tumor response. We also discussed future works on extracting disease-specific features, combining multiple and complementary features in response modeling, delineating tumor in multimodality images, and exploring biological explanations of these advanced features. Results: Advanced PET image features considering spatial information, such as tumor volume, tumor shape, total glycolytic volume, histogram distance, and texture features (characterizing spatial distribution of FDG uptake) have been found more informative than the traditional SUVmax for the prediction of tumor response. Advanced CT features, including volumetric, attenuation, morphologic, structure, and texture descriptors, have also been found advantage over the traditional RECIST and WHO criteria in certain tumor types. Conclusions: Advanced, quantitative FDG PET/CT image features have been shown promising for the evaluation of tumor response. With the emerging multi-modality imaging performed at multiple time points for each patient, it becomes more important to analyze the serial images quantitatively, select and combine both complementary and contradictory information from various sources, for accurate and personalized evaluation of tumor response to therapy.

  12. Response of early active rheumatoid arthritis to tumor necrosis factor inhibitors: evaluation by magnetic resonance imaging.

    PubMed

    Hirose, Wataru; Nishikawa, Kenichiro; Hirose, Masuko; Nanki, Toshihiro; Sugimoto, Hideharu

    2009-01-01

    Inflammatory changes (synovitis and bone marrow edema) and destructive changes (bone erosion) were evaluated by magnetic resonance imaging (MRI) in patients with rheumatoid arthritis (RA), and their relations with disease activity were assessed during treatment with tumor necrosis factor (TNF) inhibitors. Ten patients with early active RA underwent MRI at 0 and 16 weeks of TNF-inhibitor treatment. The carpal bones of the dominant hand were evaluated by the outcome measures in rheumatology clinical trials MRI score for RA. After 16 weeks, the mean disease activity score (DAS 28) decreased significantly from 5.54 to 2.70, while the number of tender joints, number of swollen joints, and inflammatory parameters were also significantly improved. The mean synovitis and marrow edema scores determined by MRI showed a significant decrease from 6.1 to 2.2 and 12.8 to 6.2, respectively, while the annual bone-erosion progression score decreased from 12.6 to 2.0. Although synovitis persisted in some patients, imaging remission was achieved in two patients. In conclusion, TNF-inhibitor therapy achieved an early decrease of disease activity and MRI revealed amelioration of joint destruction. The MRI score for RA is useful for assessing the early response to TNF inhibitors. PMID:18762862

  13. The use of thermographic imaging to evaluate therapeutic response in human tumour xenograft models.

    PubMed

    Hussain, Nosheen; Connah, David; Ugail, Hassan; Cooper, Patricia A; Falconer, Robert A; Patterson, Laurence H; Shnyder, Steven D

    2016-01-01

    Non-invasive methods to monitor tumour growth are an important goal in cancer drug development. Thermographic imaging systems offer potential in this area, since a change in temperature is known to be induced due to changes within the tumour microenvironment. This study demonstrates that this imaging modality can be applied to a broad range of tumour xenografts and also, for the first time, the methodology's suitability to assess anti-cancer agent efficacy. Mice bearing subcutaneously implanted H460 lung cancer xenografts were treated with a novel vascular disrupting agent, ICT-2552, and the cytotoxin doxorubicin. The effects on tumour temperature were assessed using thermographic imaging over the first 6 hours post-administration and subsequently a further 7 days. For ICT-2552 a significant initial temperature drop was observed, whilst for both agents a significant temperature drop was seen compared to controls over the longer time period. Thus thermographic imaging can detect functional differences (manifesting as temperature reductions) in the tumour response to these anti-cancer agents compared to controls. Importantly, these effects can be detected in the first few hours following treatment and therefore the tumour is observable non-invasively. As discussed, this technique will have considerable 3Rs benefits in terms of reduction and refinement of animal use. PMID:27491535

  14. The use of thermographic imaging to evaluate therapeutic response in human tumour xenograft models

    PubMed Central

    Hussain, Nosheen; Connah, David; Ugail, Hassan; Cooper, Patricia A.; Falconer, Robert A.; Patterson, Laurence H.; Shnyder, Steven D.

    2016-01-01

    Non-invasive methods to monitor tumour growth are an important goal in cancer drug development. Thermographic imaging systems offer potential in this area, since a change in temperature is known to be induced due to changes within the tumour microenvironment. This study demonstrates that this imaging modality can be applied to a broad range of tumour xenografts and also, for the first time, the methodology’s suitability to assess anti-cancer agent efficacy. Mice bearing subcutaneously implanted H460 lung cancer xenografts were treated with a novel vascular disrupting agent, ICT-2552, and the cytotoxin doxorubicin. The effects on tumour temperature were assessed using thermographic imaging over the first 6 hours post-administration and subsequently a further 7 days. For ICT-2552 a significant initial temperature drop was observed, whilst for both agents a significant temperature drop was seen compared to controls over the longer time period. Thus thermographic imaging can detect functional differences (manifesting as temperature reductions) in the tumour response to these anti-cancer agents compared to controls. Importantly, these effects can be detected in the first few hours following treatment and therefore the tumour is observable non-invasively. As discussed, this technique will have considerable 3Rs benefits in terms of reduction and refinement of animal use. PMID:27491535

  15. Evaluation of inflammatory responses against muscle larvae of different Trichinella species by an image analysis system.

    PubMed

    Bruschi, F; Marucci, G; Pozio, E; Masetti, M

    2009-02-23

    The aim of this study was to evaluate the inflammatory response in the muscle tissue against Trichinella larvae of encapsulated (T. spiralis, T. britovi) and non-encapsulated (T. pseudospiralis) species. The inflammatory response was estimated in histological sections of muscle tissues from Trichinella-infected CD1 mice by a newly developed method. Nuclei were stained with one fluorescent probe, which binds nucleic acids with high affinity, and fluorescence was analysed by a software program. Evaluation of the relative fluorescence units was performed in both peri-capsular (close to the nurse cell-parasite complex) and extra-capsular (where the parasite was not visible) areas. The increase in the number of nuclei in the muscle tissues of Trichinella-infected mice was considered an inflammation marker, since uninfected muscles show low nucleus density. In order to evaluate differences in the nitrosylation pattern between encapsulated (T. spiralis, T. britovi) and non-encapsulated (T. pseudospiralis, Trichinella papuae, Trichinella zimbabwensis) species, L(1) larvae were tested by immunoblotting with an anti-nitrotyrosine polyclonal antibody. Inflammation induced by T. spiralis larvae in muscle tissues is statistically higher than that elicited by the other species, both in peri- and extra-capsular areas. Nitrosylation occurs at a higher level in encapsulated than in non-encapsulated species. The method developed in this work allows demonstration of differences in the host inflammatory response against encapsulated and non-encapsulated Trichinella species. PMID:19046814

  16. Positron emission tomography in imaging evaluation of staging, restaging, treatment response, and prognosis in prostate cancer.

    PubMed

    Jadvar, Hossein

    2016-05-01

    Prostate cancer is a prevalent public health problem worldwide. While imaging has played a major role in this disease, there still remain many challenges and opportunities. Positron emission tomography with various physiologically based radiotracers is fundamentally suited to interrogate this biologically and clinically heterogeneous disease along the course of its natural history. In this article, I review briefly the published evidence for the use of positron emission tomography with 18F-fluorodeoxyglucose, 11C-acetate, and 18F- or 11C-choline in the imaging evaluation of prostate cancer. Although the focus of the article will be on these radiotracers given the accumulated experience with them, but I will also comment on the outlook for the use of other emerging PET radiotracers such as those targeted to the prostate-specific membrane antigen and the amino acid metabolism pathway. It is anticipated that PET will play major role in the evaluation of prostate cancer in the current evidence-based medicine environment. There will also be exciting novel prospects for the use of therapeutic-diagnostic (theransotic) pairs in the management of patients with prostate cancer. PMID:27193789

  17. Evaluation of Hepatic Tumor Response to Yttrium-90 Radioembolization Therapy using Texture Signatures Generated from Contrast-Enhanced CT Images

    PubMed Central

    Gensure, Rebekah H.; Foran, David J.; Lee, Vincent M.; Gendel, Vyacheslav M.; Jabbour, Salma K.; Carpizo, Darren R.; Nosher, John L.; Yang, Lin

    2012-01-01

    Rationale and Objectives The aim of this study was to explore the use of texture features generated from liver computed tomographic (CT) datasets as potential image-based indicators of patient response to radioembolization (RE) with yttrium-90 (90Y) resin microspheres, an emerging locoregional therapy for advanced-stage liver cancer. Materials and Methods Overall post-therapy survival and percent change in serologic tumor marker at three months post-therapy represent the primary clinical outcomes in this study. Thirty advanced-stage liver cancer cases (primary and metastatic) treated with RE over a three year period were included. Texture signatures for tumor regions, which were delineated to reveal boundaries with normal regions, were computed from pre-treatment contrast-enhanced liver CT studies and evaluated for their ability to classify patient serologic response and survival. Results A series of systematic leave-one-out cross-validation studies using soft-margin support vector machine (SVM) classifiers showed hepatic tumor texton and local binary pattern (LBP) signatures both achieve high accuracy (96%) in discriminating subjects in terms of their serologic response. The image-based indicators were also accurate in classifying subjects by survival status (80% and 93% accuracy for texton and LBP signatures, respectively). Conclusions Hepatic texture signatures generated from tumor regions on pre-treatment triphasic CT studies were highly accurate in differentiating among subjects in terms of serologic response and survival. These image-based computational markers show promise as potential predictive tools in candidate evaluation for locoregional therapy such as RE. PMID:22841288

  18. Evaluating the bending response of two osseointegrated transfemoral implant systems using 3D digital image correlation.

    PubMed

    Thompson, Melanie L; Backman, David; Branemark, Rickard; Mechefske, Chris K

    2011-05-01

    Osseointegrated transfemoral implants have been introduced as a prosthetic solution for above knee amputees. They have shown great promise, providing an alternative for individuals who could not be accommodated by conventional, socket-based prostheses; however, the occurrence of device failures is of concern. In an effort to improve the strength and longevity of the device, a new design has been proposed. This study investigates the mechanical behavior of the new taper-based assembly in comparison to the current hex-based connection for osseointegrated transfemoral implant systems. This was done to better understand the behavior of components under loading, in order to optimize the assembly specifications and improve the useful life of the system. Digital image correlation was used to measure surface strains on two assemblies during static loading in bending. This provided a means to measure deformation over the entire sample and identify critical locations as the assembly was subjected to a series of loading conditions. It provided a means to determine the effects of tightening specifications and connection geometry on the material response and mechanical behavior of the assemblies. Both osseoinegrated assemblies exhibited improved strength and mechanical performance when tightened to a level beyond the current specified tightening torque of 12 N m. This was shown by decreased strain concentration values and improved distribution of tensile strain. Increased tightening torque provides an improved connection between components regardless of design, leading to increased torque retention, decreased peak tensile strain values, and a more gradual, primarily compressive distribution of strains throughout the assembly. PMID:21599097

  19. GOES-R Advanced Baseline Imager: spectral response functions and radiometric biases with the NPP Visible Infrared Imaging Radiometer Suite evaluated for desert calibration sites.

    PubMed

    Pearlman, Aaron; Pogorzala, David; Cao, Changyong

    2013-11-01

    The Advanced Baseline Imager (ABI), which will be launched in late 2015 on the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellite R-series satellite, will be evaluated in terms of its data quality postlaunch through comparisons with other satellite sensors such as the recently launched Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership satellite. The ABI has completed much of its prelaunch characterization and its developers have generated and released its channel spectral response functions (response versus wavelength). Using these responses and constraining a radiative transfer model with ground reflectance, aerosol, and water vapor measurements, we simulate observed top of atmosphere (TOA) reflectances for analogous visible and near infrared channels of the VIIRS and ABI sensors at the Sonoran Desert and White Sands National Monument sites and calculate the radiometric biases and their uncertainties. We also calculate sensor TOA reflectances using aircraft hyperspectral data from the Airborne Visible/Infrared Imaging Spectrometer to validate the uncertainties in several of the ABI and VIIRS channels and discuss the potential for validating the others. Once on-orbit, calibration scientists can use these biases to ensure ABI data quality and consistency to support the numerical weather prediction community and other data users. They can also use the results for ABI or VIIRS anomaly detection and resolution. PMID:24216671

  20. Evaluation of area strain response of dielectric elastomer actuator using image processing technique

    NASA Astrophysics Data System (ADS)

    Sahu, Raj K.; Sudarshan, Koyya; Patra, Karali; Bhaumik, Shovan

    2014-03-01

    Dielectric elastomer actuator (DEA) is a kind of soft actuators that can produce significantly large electric-field induced actuation strain and may be a basic unit of artificial muscles and robotic elements. Understanding strain development on a pre-stretched sample at different regimes of electrical field is essential for potential applications. In this paper, we report about ongoing work on determination of area strain using digital camera and image processing technique. The setup, developed in house consists of low cost digital camera, data acquisition and image processing algorithm. Samples have been prepared by biaxially stretched acrylic tape and supported between two cardboard frames. Carbon-grease has been pasted on the both sides of the sample, which will be compliant with electric field induced large deformation. Images have been grabbed before and after the application of high voltage. From incremental image area, strain has been calculated as a function of applied voltage on a pre-stretched dielectric elastomer (DE) sample. Area strain has been plotted with the applied voltage for different pre-stretched samples. Our study shows that the area strain exhibits nonlinear relationship with applied voltage. For same voltage higher area strain has been generated on a sample having higher pre-stretched value. Also our characterization matches well with previously published results which have been done with costly video extensometer. The study may be helpful for the designers to fabricate the biaxial pre-stretched planar actuator from similar kind of materials.

  1. Evaluator Responsiveness to Stakeholders

    ERIC Educational Resources Information Center

    Azzam, Tarek

    2010-01-01

    A simulation study was conducted in an attempt to examine how evaluators modify their evaluation design in response to differing stakeholder groups. In this study, evaluators were provided with a fictitious description of a school-based program. They were then asked to design an evaluation of the program. After the evaluation design decisions were…

  2. Diagnostic imaging to detect and evaluate response to therapy in bone metastases from prostate cancer: current modalities and new horizons.

    PubMed

    Evangelista, Laura; Bertoldo, Francesco; Boccardo, Francesco; Conti, Giario; Menchi, Ilario; Mungai, Francesco; Ricardi, Umberto; Bombardieri, Emilio

    2016-07-01

    Different therapeutic options for the management of prostate cancer (PC) have been developed, and some are successful in providing crucial improvement in both survival and quality of life, especially in patients with metastatic castration-resistant PC. In this scenario, diverse combinations of radiopharmaceuticals (for targeting bone, cancer cells and receptors) and nuclear medicine modalities (e.g. bone scan, SPECT, SPECT/CT, PET and PET/CT) are now available for imaging bone metastases. Some radiopharmaceuticals are approved, currently available and used in the routine clinical setting, while others are not registered and are still under evaluation, and should therefore be considered experimental. On the other hand, radiologists have other tools, in addition to CT, that can better visualize bone localization and medullary involvement, such as multimodal MRI. In this review, the authors provide an overview of current management of advanced PC and discuss the choice of diagnostic modality for the detection of metastatic skeletal lesions in different phases of the disease. In addition to detection of bone metastases, the evaluation of response to therapy is another critical issue, since it remains one of the most important open questions that a multidisciplinary team faces when optimizing the management of PC. The authors emphasize the role of nuclear modalities that can presently be used in clinical practice, and also look at future perspectives based on relevant clinical data with novel radiopharmaceuticals. PMID:26956538

  3. Evaluation of image quality

    NASA Technical Reports Server (NTRS)

    Pavel, M.

    1993-01-01

    This presentation outlines in viewgraph format a general approach to the evaluation of display system quality for aviation applications. This approach is based on the assumption that it is possible to develop a model of the display which captures most of the significant properties of the display. The display characteristics should include spatial and temporal resolution, intensity quantizing effects, spatial sampling, delays, etc. The model must be sufficiently well specified to permit generation of stimuli that simulate the output of the display system. The first step in the evaluation of display quality is an analysis of the tasks to be performed using the display. Thus, for example, if a display is used by a pilot during a final approach, the aesthetic aspects of the display may be less relevant than its dynamic characteristics. The opposite task requirements may apply to imaging systems used for displaying navigation charts. Thus, display quality is defined with regard to one or more tasks. Given a set of relevant tasks, there are many ways to approach display evaluation. The range of evaluation approaches includes visual inspection, rapid evaluation, part-task simulation, and full mission simulation. The work described is focused on two complementary approaches to rapid evaluation. The first approach is based on a model of the human visual system. A model of the human visual system is used to predict the performance of the selected tasks. The model-based evaluation approach permits very rapid and inexpensive evaluation of various design decisions. The second rapid evaluation approach employs specifically designed critical tests that embody many important characteristics of actual tasks. These are used in situations where a validated model is not available. These rapid evaluation tests are being implemented in a workstation environment.

  4. Accommodation response for integral photography still images

    NASA Astrophysics Data System (ADS)

    Yano, Sumio; Park, Min-Chul

    2015-05-01

    In this paper the accommodation responses for integral photography still images were measured. The experimental results showed that the accommodation responses for integral photography images showed a linear change with images showing the depth position of integral photography, even if the integral photography images were located out of the depth of the field. Furthermore, the discrimination of depth perception, which relates to a blur effect in integral photography images, was subjectively evaluated for the examination of its influence on the accommodation response. As a result, the range of the discrimination of depth perception was narrow in comparison to the range of the rectilinear accommodation response. However, these results were consistent according to the propensity of statistical significance for the discrimination of depth perception in the out range of subjectively effective discriminations.

  5. CRT image recording evaluation

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Performance capabilities and limitations of a fiber optic coupled line scan CRT image recording system were investigated. The test program evaluated the following components: (1). P31 phosphor CRT with EMA faceplate; (2). P31 phosphor CRT with clear clad faceplate; (3). Type 7743 semi-gloss dry process positive print paper; (4). Type 777 flat finish dry process positive print paper; (5). Type 7842 dry process positive film; and (6). Type 1971 semi-gloss wet process positive print paper. Detailed test procedures used in each test are provided along with a description of each test, the test data, and an analysis of the results.

  6. Noninvasive In Vivo Imaging to Evaluate Immune Responses and Antimicrobial Therapy against Staphylococcus aureus and USA300 MRSA Skin Infections

    PubMed Central

    Cho, John S.; Zussman, Jamie; Donegan, Niles P.; Irene Ramos, Romela; Garcia, Nairy C.; Uslan, Daniel Z.; Iwakura, Yoichiro; Simon, Scott I.; Cheung, Ambrose L.; Modlin, Robert L.; Kim, Jenny; Miller, Lloyd S.

    2011-01-01

    Staphylococcus aureus skin infections represent a significant public health threat because of the emergence of antibiotic-resistant strains such as methicillin-resistant S. aureus (MRSA). As greater understanding of protective immune responses and more effective antimicrobial therapies are needed, a S. aureus skin wound infection model was developed in which full-thickness scalpel cuts on the backs of mice were infected with a bioluminescent S. aureus (methicillin sensitive) or USA300 community-acquired MRSA strain and in vivo imaging was used to noninvasively monitor the bacterial burden. In addition, the infection-induced inflammatory response was quantified using in vivo fluorescence imaging of LysEGFP mice. Using this model, we found that both IL-1α and IL-1β contributed to host defense during a wound infection, whereas IL-1β was more critical during an intradermal S. aureus infection. Furthermore, treatment of a USA300 MRSA skin infection with retapamulin ointment resulted in up to 85-fold reduction in bacterial burden and a 53% decrease in infection-induced inflammation. In contrast, mupirocin ointment had minimal clinical activity against this USA300 strain, resulting in only a 2-fold reduction in bacterial burden. Taken together, this S. aureus wound infection model provides a valuable preclinical screening method to investigate cutaneous immune responses and the efficacy of topical antimicrobial therapies. PMID:21191403

  7. Histological Evaluation of Prostate Tissue Response to Image-Guided Transurethral Thermal Therapy After a 48h Recovery Period

    NASA Astrophysics Data System (ADS)

    Boyes, Aaron; Tang, Kee; Chopra, Rajiv; Bronskill, Michael

    2009-04-01

    Image-guided transurethral ultrasound thermal therapy shows strong potential for sparing of critical adjacent structures during prostate cancer treatment. Preclinical experiments were conducted to provide further information on the extent of the treatment margin. Four experiments were carried out in a canine model to investigate the pathology of this margin during the early stages of recovery and were compared to previous results obtained immediately post-treatment. Sedated animals were placed in a 1.5T clinical MRI, and the heating device was positioned accurately within the prostatic urethra with image guidance. Using an MRI-compatible system, the ultrasound device was rotated 365° treating a prescribed volume contained within the gland. Quantitative temperature maps were acquired throughout the treatment, providing feedback information for device control. Animals were allowed to recover and, after 48h, an imaging protocol including T2 and contrast enhanced (CE) MRI was repeated before the animals were sacrificed. Prostate sections were stained with H&E. Careful slice alignment methods during histological procedures and image registration were employed to ensure good correspondence between MR images and microscopy. Although T2 MRI revealed no lesion acutely, a hypo-intense region was clearly visible 2 days post-treatment. The lesion volume defined by CE-MRI increased appreciably during this time. Whole-mount H&E sections showed that the margin between coagulated and normal-appearing cells narrowed during recovery, typically to a width of under 1mm compared to 3mm acutely. These results illustrate the high level of precision achievable with transurethral thermal therapy and suggest methods to monitor the physiological response non-invasively.

  8. An imaging-based platform for high-content, quantitative evaluation of therapeutic response in 3D tumour models

    NASA Astrophysics Data System (ADS)

    Celli, Jonathan P.; Rizvi, Imran; Blanden, Adam R.; Massodi, Iqbal; Glidden, Michael D.; Pogue, Brian W.; Hasan, Tayyaba

    2014-01-01

    While it is increasingly recognized that three-dimensional (3D) cell culture models recapitulate drug responses of human cancers with more fidelity than monolayer cultures, a lack of quantitative analysis methods limit their implementation for reliable and routine assessment of emerging therapies. Here, we introduce an approach based on computational analysis of fluorescence image data to provide high-content readouts of dose-dependent cytotoxicity, growth inhibition, treatment-induced architectural changes and size-dependent response in 3D tumour models. We demonstrate this approach in adherent 3D ovarian and pancreatic multiwell extracellular matrix tumour overlays subjected to a panel of clinically relevant cytotoxic modalities and appropriately designed controls for reliable quantification of fluorescence signal. This streamlined methodology reads out the high density of information embedded in 3D culture systems, while maintaining a level of speed and efficiency traditionally achieved with global colorimetric reporters in order to facilitate broader implementation of 3D tumour models in therapeutic screening.

  9. SLI Thermal Imaging Requirements Evaluation

    NASA Astrophysics Data System (ADS)

    Hoffman, E. H.; Woody, L. M.; Wirth, S. M.; Smith, D. S.

    2015-12-01

    The Landsat program has provided a continuous record of global terrestrial imagery since 1972. This data record is an invaluable resource for determining long term trends and monitoring rates of change in land usage, forest health, water quality, and glacier retreat. In 2014, the National Aeronautics and Space Administration (NASA), supported by the United States Geological Survey (USGS), initiated the sustainable land imaging (SLI) architecture study to develop an affordable system design for acquiring future terrestrial imagery compatible with the existing Landsat data record. The principal objective has been to leverage recent advances in focal plane technologies to enable smaller, lower-cost instruments and launch options. We present an evaluation of the trade space implied by the SLI thermal imaging requirements as well as the performance potential of enabling technologies. Multiple approaches, each incorporating measured performance data for state-of-the-art detectors, are investigated to simultaneously optimize instrument mass and volume, spatial response, radiometric sensitivity, and radiometric uncertainty.

  10. Utilisation of a thoracic oncology database to capture radiological and pathological images for evaluation of response to chemotherapy in patients with malignant pleural mesothelioma

    PubMed Central

    Carey, George B; Kazantsev, Stephanie; Surati, Mosmi; Rolle, Cleo E; Kanteti, Archana; Sadiq, Ahad; Bahroos, Neil; Raumann, Brigitte; Madduri, Ravi; Dave, Paul; Starkey, Adam; Hensing, Thomas; Husain, Aliya N; Vokes, Everett E; Vigneswaran, Wickii; Armato, Samuel G; Kindler, Hedy L; Salgia, Ravi

    2012-01-01

    Objective An area of need in cancer informatics is the ability to store images in a comprehensive database as part of translational cancer research. To meet this need, we have implemented a novel tandem database infrastructure that facilitates image storage and utilisation. Background We had previously implemented the Thoracic Oncology Program Database Project (TOPDP) database for our translational cancer research needs. While useful for many research endeavours, it is unable to store images, hence our need to implement an imaging database which could communicate easily with the TOPDP database. Methods The Thoracic Oncology Research Program (TORP) imaging database was designed using the Research Electronic Data Capture (REDCap) platform, which was developed by Vanderbilt University. To demonstrate proof of principle and evaluate utility, we performed a retrospective investigation into tumour response for malignant pleural mesothelioma (MPM) patients treated at the University of Chicago Medical Center with either of two analogous chemotherapy regimens and consented to at least one of two UCMC IRB protocols, 9571 and 13473A. Results A cohort of 22 MPM patients was identified using clinical data in the TOPDP database. After measurements were acquired, two representative CT images and 0–35 histological images per patient were successfully stored in the TORP database, along with clinical and demographic data. Discussion We implemented the TORP imaging database to be used in conjunction with our comprehensive TOPDP database. While it requires an additional effort to use two databases, our database infrastructure facilitates more comprehensive translational research. Conclusions The investigation described herein demonstrates the successful implementation of this novel tandem imaging database infrastructure, as well as the potential utility of investigations enabled by it. The data model presented here can be utilised as the basis for further development of other larger

  11. An imaging-based platform for high-content, quantitative evaluation of therapeutic response in 3D tumour models

    PubMed Central

    Celli, Jonathan P.; Rizvi, Imran; Blanden, Adam R.; Massodi, Iqbal; Glidden, Michael D.; Pogue, Brian W.; Hasan, Tayyaba

    2014-01-01

    While it is increasingly recognized that three-dimensional (3D) cell culture models recapitulate drug responses of human cancers with more fidelity than monolayer cultures, a lack of quantitative analysis methods limit their implementation for reliable and routine assessment of emerging therapies. Here, we introduce an approach based on computational analysis of fluorescence image data to provide high-content readouts of dose-dependent cytotoxicity, growth inhibition, treatment-induced architectural changes and size-dependent response in 3D tumour models. We demonstrate this approach in adherent 3D ovarian and pancreatic multiwell extracellular matrix tumour overlays subjected to a panel of clinically relevant cytotoxic modalities and appropriately designed controls for reliable quantification of fluorescence signal. This streamlined methodology reads out the high density of information embedded in 3D culture systems, while maintaining a level of speed and efficiency traditionally achieved with global colorimetric reporters in order to facilitate broader implementation of 3D tumour models in therapeutic screening. PMID:24435043

  12. Body image inflexibility mediates the relationship between body image evaluation and maladaptive body image coping strategies.

    PubMed

    Mancuso, Serafino G

    2016-03-01

    Body image inflexibility, the unwillingness to experience negative appearance-related thoughts and emotions, is associated with negative body image and eating disorder symptoms. The present study investigated whether body image inflexibility mediated the relationship between body image evaluation and maladaptive body image coping strategies (appearance-fixing and experiential avoidance) in a college and community sample comprising 156 females aged 18-51 years (M=22.76, SD=6.96). Controlling for recruitment source (college vs. community), body image inflexibility fully mediated the relationship between body image evaluation and maladaptive body image coping strategies. Results indicated that an unwillingness to experience negative appearance-related thoughts and emotions is likely responsible for negative body image evaluation's relationship to appearance-fixing behaviours and experiential avoidance. Findings support extant evidence that interventions that explicitly target body image inflexibility, such as Acceptance and Commitment Therapy, may have utility in treating body dissatisfaction in nonclinical populations. PMID:26595857

  13. Development of a single vial kit formulation of [99mTc]-labeled doxorubicin for tumor imaging and treatment response assessment-preclinical evaluation and preliminary human results.

    PubMed

    Kumar, Pardeep; Singh, Baljinder; Ghai, Anchal; Hazari, Puja P; Mittal, B R; Mishra, Anil K

    2015-05-30

    The present study describes the successful radiolabeling of [99mTcO(-) 4 ] with doxorubicin, and the resultant product was formulated in to a ready-to-label lyophilized single vial kit preparation for convenient use in a routine clinical setting. The radiolabeled preparation of [99mTc]-doxorubicin exhibited a high radiolabeling efficiency of more than 95.0%, serum stability for up to 24 h, and shelf-life of lyophilized cold kits was more than 6 months. Animal imaging data in tumor-bearing mice demonstrated that [99mTc]-doxorubicin accumulated in the tumor site with high target (tumor) to non-target (contra-lateral thigh) ratio (3.2 ± 0.5). The ratio decreased to 1.2 ± 0.6 indicating a good response on follow up imaging performed after 2 weeks of doxorubicin treatment. [99mTc]-doxorubicin scintigraphic data in human volunteers supported the hepato-renal excretion of the radiotracer as reflected by the increased accumulation of the radiotracer as a function of time in intestine, kidneys, and urinary bladder. Further, imaging in patients (very limited number) indicated that the technique may be useful in the detection of active sarcoma and post treatment (surgery/chemotherapy) remission or absence of the disease. The technique, however, needs validation through further preclinical evaluation and imaging in a larger number of patients. PMID:25968484

  14. Noninvasive imaging of immune responses

    PubMed Central

    Rashidian, Mohammad; Keliher, Edmund J.; Bilate, Angelina M.; Duarte, Joao N.; Wojtkiewicz, Gregory R.; Jacobsen, Johanne Tracey; Cragnolini, Juanjo; Swee, Lee Kim; Victora, Gabriel D.; Weissleder, Ralph; Ploegh, Hidde L.

    2015-01-01

    At their margins, tumors often contain neutrophils, dendritic cells, and activated macrophages, which express class II MHC and CD11b products. The interplay between stromal cells, tumor cells, and migratory cells such as lymphocytes creates opportunities for noninvasive imaging of immune responses. We developed alpaca-derived antibody fragments specific for mouse class II MHC and CD11b products, expressed on the surface of a variety of myeloid cells. We validated these reagents by flow cytometry and two-photon microscopy to obtain images at cellular resolution. To enable noninvasive imaging of the targeted cell populations, we developed a method to site-specifically label VHHs [the variable domain (VH) of a camelid heavy-chain only antibody] with 18F or 64Cu. Radiolabeled VHHs rapidly cleared the circulation (t1/2 ≈ 20 min) and clearly visualized lymphoid organs. We used VHHs to explore the possibility of imaging inflammation in both xenogeneic and syngeneic tumor models, which resulted in detection of tumors with remarkable specificity. We also imaged the infiltration of myeloid cells upon injection of complete Freund’s adjuvant. Both anti-class II MHC and anti-CD11b VHHs detected inflammation with excellent specificity. Given the ease of manufacture and labeling of VHHs, we believe that this method could transform the manner in which antitumor responses and/or infectious events may be tracked. PMID:25902531

  15. Noninvasive imaging of immune responses.

    PubMed

    Rashidian, Mohammad; Keliher, Edmund J; Bilate, Angelina M; Duarte, Joao N; Wojtkiewicz, Gregory R; Jacobsen, Johanne Tracey; Cragnolini, Juanjo; Swee, Lee Kim; Victora, Gabriel D; Weissleder, Ralph; Ploegh, Hidde L

    2015-05-12

    At their margins, tumors often contain neutrophils, dendritic cells, and activated macrophages, which express class II MHC and CD11b products. The interplay between stromal cells, tumor cells, and migratory cells such as lymphocytes creates opportunities for noninvasive imaging of immune responses. We developed alpaca-derived antibody fragments specific for mouse class II MHC and CD11b products, expressed on the surface of a variety of myeloid cells. We validated these reagents by flow cytometry and two-photon microscopy to obtain images at cellular resolution. To enable noninvasive imaging of the targeted cell populations, we developed a method to site-specifically label VHHs [the variable domain (VH) of a camelid heavy-chain only antibody] with (18)F or (64)Cu. Radiolabeled VHHs rapidly cleared the circulation (t1/2 ≈ 20 min) and clearly visualized lymphoid organs. We used VHHs to explore the possibility of imaging inflammation in both xenogeneic and syngeneic tumor models, which resulted in detection of tumors with remarkable specificity. We also imaged the infiltration of myeloid cells upon injection of complete Freund's adjuvant. Both anti-class II MHC and anti-CD11b VHHs detected inflammation with excellent specificity. Given the ease of manufacture and labeling of VHHs, we believe that this method could transform the manner in which antitumor responses and/or infectious events may be tracked. PMID:25902531

  16. The Role of Diffusion-Weighted Magnetic Resonance Imaging in the Treatment Response Evaluation of Hepatocellular Carcinoma Patients Treated With Radiation Therapy

    SciTech Connect

    Yu, Jeong Il; Park, Hee Chul; Lim, Do Hoon; Choi, Yunseon; Jung, Sang Hoon; Paik, Seung Woon; Kim, Seong Hyun; Jeong, Woo Kyoung; Kim, Young Kon

    2014-07-15

    Purpose: We investigated the role of diffusion-weighted magnetic resonance imaging (DW MRI) as a response evaluation indicator for hepatocellular carcinoma (HCC) treated with radiation therapy (RT). Methods and Materials: Inclusion criteria of this retrospective study were DW MRI acquisition within 1 month before and 3 to 5 months after RT. In total, 48 patients were enrolled. Two radiation oncologists measured the apparent diffusion coefficient (ADC). Possible predictive factors, including alteration of the ADC value before and 3 to 5 month after RT, in relation to local progression-free survival (LPFS) were analyzed and compared. Results: Three months after RT, 6 patients (12.5%) showed a complete response, and 27 patients (56.3%) showed a partial response when evaluated using the modified response evaluation criteria in solid tumors (mRECIST). The average ADC ± SD values were 1.21 ± 0.27 ( × 10{sup −3} mm{sup 2}/s) before and 1.41 ± 0.36 ( × 10{sup −3} mm{sup 2}/s) after RT (P<.001). The most significant prognostic factor related to LPFS was mRECIST (P<.001). The increment of ADC value (≥20%) was also a significant factor (P=.02), but RECIST (version 1.1; P=.11) was not. When RECIST was combined with the increment of ADC value (≥20%), the LPFS rates were significantly different between the groups (P=.004), and the area under the curve value (0.745) was comparable with that of mRECIST (0.765). Conclusions: ADC value change before and after RT in HCC was closely related to LPFS. ADC value and RECIST may substitute for mRECIST in patients who cannot receive contrast agents.

  17. Evaluation of Vibration Response Imaging (VRI) Technique and Difference in VRI Indices Among Non-Smokers, Active Smokers, and Passive Smokers

    PubMed Central

    Jiang, Hongying; Chen, Jichao; Cao, Jinying; Mu, Lan; Hu, Zhenyu; He, Jian

    2015-01-01

    Background Vibration response imaging (VRI) is a new technology for lung imaging. Active smokers and non-smokers show differences in VRI findings, but no data are available for passive smokers. The aim of this study was to evaluate the use of VRI and to assess the differences in VRI findings among non-smokers, active smokers, and passive smokers. Material/Methods Healthy subjects (n=165: 63 non-smokers, 56 active smokers, and 46 passive smokers) with normal lung function were enrolled. Medical history, physical examination, lung function test, and VRI were performed for all subjects. Correlation between smoking index and VRI scores (VRIS) were performed. Results VRI images showed progressive and regressive stages representing the inspiratory and expiratory phases bilaterally in a vertical and synchronized manner in non-smokers. Vibration energy curves with low expiratory phase and plateau were present in 6.35% and 3.17%, respectively, of healthy non-smokers, 41.07% and 28.60% of smokers, and 39.13% and 30.43% of passive smokers, respectively. The massive energy peak in the non-smokers, smokers, and passive-smokers was 1.77±0.27, 1.57±0.29, and 1.66±0.33, respectively (all P<0.001). A weak but positive correlation was observed between VRIS and smoking index. Conclusions VRI can intuitively show the differences between non-smokers and smokers. VRI revealed that passive smoking can also harm the lungs. VRI could be used to visually persuade smokers to give up smoking. PMID:26212715

  18. Online Course Evaluations Response Rates

    ERIC Educational Resources Information Center

    Guder, Faruk; Malliaris, Mary

    2013-01-01

    This paper studies the reasons for low response rates in online evaluations. Survey data are collected from the students to understand factors that might affect student participation in the course evaluation process. When course evaluations were opened to the student body, an email announcement was sent to all students, and a reminder email was…

  19. Evaluation of treatment response using integrated 18F-labeled choline positron emission tomography/magnetic resonance imaging in adolescents with intracranial non-germinomatous germ cell tumours.

    PubMed

    Tsouana, Eva; Stoneham, Sara; Fersht, Naomi; Kitchen, Neil; Gaze, Mark; Bomanji, Jamshed; Fraioli, Francesco; Hargrave, Darren; Shankar, Ananth

    2015-09-01

    The efficacy of hybrid 18F-Fluroethyl-Choline (FEC) positron emission tomography (PET)/magnetic resonance imaging (MRI) was investigated as an imaging modality for diagnosis and assessment of treatment response and remission status in four patients with proven or suspected intracranial non-germinomatous germ cell tumours (NGGCT). In two patients faint or absent choline avidity correlated with negative histology, whereas in other two patients, persistent choline avidity in the residual mass was suggestive of presence of viable tumour, subsequently confirmed histologically. We conclude that FEC-PET/MRI may be an effective imaging tool in detecting viable residual tumour in patients with intracranial NGGCT post treatment. PMID:25854508

  20. Imaging radiation response in tumor and normal tissue

    PubMed Central

    Rafat, Marjan; Ali, Rehan; Graves, Edward E

    2015-01-01

    Although X-ray computed tomography (CT) and magnetic resonance imaging (MRI) are the primary imaging modalities used in the clinic to monitor tumor response to radiation therapy, multi-modal molecular imaging may facilitate improved early and specific evaluation of this process. Fast and accurate imaging that can provide both quantitative and biological information is necessary to monitor treatment and ultimately to develop individualized treatment options for patients. A combination of molecular and anatomic information will allow for deeper insight into the mechanisms of tumor response, which will lead to more effective radiation treatments as well as improved anti-cancer drugs. Much progress has been made in nuclear medicine imaging probes and MRI techniques to achieve increased accuracy and the evaluation of relevant biomarkers of radiation response. This review will emphasize promising molecular imaging techniques that monitor various biological processes following radiotherapy, including metabolism, hypoxia, cell proliferation, and angiogenesis. PMID:26269771

  1. Information Science and Responsive Evaluation

    ERIC Educational Resources Information Center

    Stake, Robert E.

    2014-01-01

    Responsive evaluation builds upon the methods of informal evaluation in disciplined ways: getting personally acquainted with the evaluand, observation of activities, interviewing people who are in different ways familiar with the evaluand, searching documents that reveal what happened in the past or somewhere else. It calls for sustained effort to…

  2. Evaluation of a Simplified Intravoxel Incoherent Motion (IVIM) Analysis of Diffusion-Weighted Imaging for Prediction of Tumor Size Changes and Imaging Response in Breast Cancer Liver Metastases Undergoing Radioembolization: A Retrospective Single Center Analysis.

    PubMed

    Pieper, Claus C; Sprinkart, Alois M; Meyer, Carsten; König, Roy; Schild, Hans H; Kukuk, Guido M; Mürtz, Petra

    2016-04-01

    To investigate the value of a simplified intravoxel incoherent motion (IVIM) analysis for evaluation of therapy-induced tumor changes and response of breast cancer liver metastases (mBRC) undergoing radioembolization.In 21 females (mean age 54 years, range 43-72) with mBRC tumor size changes and response evaluation criteria in solid tumors (RECIST) response to 26 primary radioembolization procedures were analyzed. Standard 1.5-T liver magnetic resonance imaging including respiratory-gated diffusion-weighted imaging (DWI) with b0 = 0 s/mm, b1 = 50 s/mm, b2 = 800 s/mm before and 6 weeks after each treatment was performed. In addition to the apparent diffusion coefficient (ADC)(0,800), the estimated diffusion coefficient D' and the perfusion fraction f' were determined using a simplified IVIM approach. For each radioembolization, the 2 largest treated metastases (if available) were analyzed. Lesions were categorized according to size changes into group A (reduction of longest diameter [LD]) and group B (LD increase) after 3 months. Radioembolization procedures were further categorized into "response" (partial response and stable disease) and "nonresponse" (progressive disease) according to RECIST after 3 months. ADC and D' are given in 10 mm/s.Forty-five metastases were analyzed. Thirty-two lesions were categorized as A; 13 as B. Before therapy, group A lesions showed significantly larger f'-values than B (P = 0.001), but ADC(0,800) and D' did not differ. After therapy, in group A lesions the ADC(0,800)- and D'-values increased and f' decreased (P < 0.0001); in contrast in group B lesions f' increased (P = 0.001). Groups could be differentiated by preinterventional f' and by changes of D' and f' between pre and postinterventional imaging (area under the curve [AUC] of 0.903, 0.747 and 1.0, respectively).Preinterventional parameters did not differ between responders and nonresponders according to RECIST. ADC(0,800)- and D'-values showed a

  3. Infrared image quality evaluation method without reference image

    NASA Astrophysics Data System (ADS)

    Yue, Song; Ren, Tingting; Wang, Chengsheng; Lei, Bo; Zhang, Zhijie

    2013-09-01

    Since infrared image quality depends on many factors such as optical performance and electrical noise of thermal imager, image quality evaluation becomes an important issue which can conduce to both image processing afterward and capability improving of thermal imager. There are two ways of infrared image quality evaluation, with or without reference image. For real-time thermal image, the method without reference image is preferred because it is difficult to get a standard image. Although there are various kinds of methods for evaluation, there is no general metric for image quality evaluation. This paper introduces a novel method to evaluate infrared image without reference image from five aspects: noise, clarity, information volume and levels, information in frequency domain and the capability of automatic target recognition. Generally, the basic image quality is obtained from the first four aspects, and the quality of target is acquired from the last aspect. The proposed method is tested on several infrared images captured by different thermal imagers. Calculate the indicators and compare with human vision results. The evaluation shows that this method successfully describes the characteristics of infrared image and the result is consistent with human vision system.

  4. Evaluation of a Simplified Intravoxel Incoherent Motion (IVIM) Analysis of Diffusion-Weighted Imaging for Prediction of Tumor Size Changes and Imaging Response in Breast Cancer Liver Metastases Undergoing Radioembolization

    PubMed Central

    Pieper, Claus C.; Sprinkart, Alois M.; Meyer, Carsten; König, Roy; Schild, Hans H.; Kukuk, Guido M.; Mürtz, Petra

    2016-01-01

    Abstract To investigate the value of a simplified intravoxel incoherent motion (IVIM) analysis for evaluation of therapy-induced tumor changes and response of breast cancer liver metastases (mBRC) undergoing radioembolization. In 21 females (mean age 54 years, range 43–72) with mBRC tumor size changes and response evaluation criteria in solid tumors (RECIST) response to 26 primary radioembolization procedures were analyzed. Standard 1.5-T liver magnetic resonance imaging including respiratory-gated diffusion-weighted imaging (DWI) with b0 = 0 s/mm2, b1 = 50 s/mm2, b2 = 800 s/mm2 before and 6 weeks after each treatment was performed. In addition to the apparent diffusion coefficient (ADC)(0,800), the estimated diffusion coefficient D′ and the perfusion fraction f′ were determined using a simplified IVIM approach. For each radioembolization, the 2 largest treated metastases (if available) were analyzed. Lesions were categorized according to size changes into group A (reduction of longest diameter [LD]) and group B (LD increase) after 3 months. Radioembolization procedures were further categorized into “response” (partial response and stable disease) and “nonresponse” (progressive disease) according to RECIST after 3 months. ADC and D′ are given in 10−6 mm2/s. Forty-five metastases were analyzed. Thirty-two lesions were categorized as A; 13 as B. Before therapy, group A lesions showed significantly larger f′-values than B (P = 0.001), but ADC(0,800) and D′ did not differ. After therapy, in group A lesions the ADC(0,800)- and D′-values increased and f′ decreased (P < 0.0001); in contrast in group B lesions f′ increased (P = 0.001). Groups could be differentiated by preinterventional f′ and by changes of D′ and f′ between pre and postinterventional imaging (area under the curve [AUC] of 0.903, 0.747 and 1.0, respectively). Preinterventional parameters did not differ between responders and nonresponders

  5. Response Classification Images in Vernier Acuity

    NASA Technical Reports Server (NTRS)

    Ahumada, Albert J., Jr.; Beard, B. L.; Ellis, Stephen R. (Technical Monitor)

    1997-01-01

    Orientation selective and local sign mechanisms have been proposed as the basis for vernier acuity judgments. Linear image features contributing to discrimination can be determined for a two choice task by adding external noise to the images and then averaging the noises separately for the four types of stimulus/response trials. This method is applied to a vernier acuity task with different spatial separations to compare the predictions of the two theories. Three well-practiced observers were presented around 5000 trials of a vernier stimulus consisting of two dark horizontal lines (5 min by 0.3 min) within additive low-contrast white noise. Two spatial separations were tested, abutting and a 10 min horizontal separation. The task was to determine whether the target lines were aligned or vertically offset. The noises were averaged separately for the four stimulus/response trial types (e.g., stimulus = offset, response = aligned). The sum of the two 'not aligned' images was then subtracted from the sum of the 'aligned' images to obtain an overall image. Spatially smoothed images were quantized according to expected variability in the smoothed images to allow estimation of the statistical significance of image features. The response images from the 10 min separation condition are consistent with the local sign theory, having the appearance of two linear operators measuring vertical position with opposite sign. The images from the abutting stimulus have the same appearance with the two operators closer together. The image predicted by an oriented filter model is similar, but has its greatest weight in the abutting region, while the response images fall to nonsignificance there. The response correlation image method, previously demonstrated for letter discrimination, clarifies the features used in vernier acuity.

  6. Implantation of brain tumors with Cf-252. Use of computed tomography and magnetic resonance imaging to guide insertion and evaluate response.

    PubMed

    Maruyama, Y; Chin, H W; Young, A B; Wang, P C; Tibbs, P; Beach, J L; Goldstein, S

    1984-07-01

    Magnetic resonance imaging (MR) was evaluated as a guide to planning and follow-up of Cf-252 neutron brachytherapy in 8 patients with malignant glioma of the cerebral hemispheres. A combination of sagittal, transverse, and coronal views allowed three-dimensional assessment of the dimensions and extent of tumor; by comparison, CT scans delineated the tumor less sharply, multiple views were not routinely obtained, and the reconstructed sagittal images were inadequate. Both techniques were complementary in enabling accurate tumor localization as well as separating enhanced zones from central avascular regions and tumor from edema. However, MR images provided more detail than serial CT scans, making MR the preferred method of follow-up. PMID:6729108

  7. Development and evaluation of a LOR-based image reconstruction with 3D system response modeling for a PET insert with dual-layer offset crystal design

    NASA Astrophysics Data System (ADS)

    Zhang, Xuezhu; Stortz, Greg; Sossi, Vesna; Thompson, Christopher J.; Retière, Fabrice; Kozlowski, Piotr; Thiessen, Jonathan D.; Goertzen, Andrew L.

    2013-12-01

    In this study we present a method of 3D system response calculation for analytical computer simulation and statistical image reconstruction for a magnetic resonance imaging (MRI) compatible positron emission tomography (PET) insert system that uses a dual-layer offset (DLO) crystal design. The general analytical system response functions (SRFs) for detector geometric and inter-crystal penetration of coincident crystal pairs are derived first. We implemented a 3D ray-tracing algorithm with 4π sampling for calculating the SRFs of coincident pairs of individual DLO crystals. The determination of which detector blocks are intersected by a gamma ray is made by calculating the intersection of the ray with virtual cylinders with radii just inside the inner surface and just outside the outer-edge of each crystal layer of the detector ring. For efficient ray-tracing computation, the detector block and ray to be traced are then rotated so that the crystals are aligned along the X-axis, facilitating calculation of ray/crystal boundary intersection points. This algorithm can be applied to any system geometry using either single-layer (SL) or multi-layer array design with or without offset crystals. For effective data organization, a direct lines of response (LOR)-based indexed histogram-mode method is also presented in this work. SRF calculation is performed on-the-fly in both forward and back projection procedures during each iteration of image reconstruction, with acceleration through use of eight-fold geometric symmetry and multi-threaded parallel computation. To validate the proposed methods, we performed a series of analytical and Monte Carlo computer simulations for different system geometry and detector designs. The full-width-at-half-maximum of the numerical SRFs in both radial and tangential directions are calculated and compared for various system designs. By inspecting the sinograms obtained for different detector geometries, it can be seen that the DLO crystal

  8. Role of 3T multiparametric-MRI with BOLD hypoxia imaging for diagnosis and post therapy response evaluation of postoperative recurrent cervical cancers

    PubMed Central

    Mahajan, Abhishek; Engineer, Reena; Chopra, Supriya; Mahanshetty, Umesh; Juvekar, S.L.; Shrivastava, S.K.; Desekar, Naresh; Thakur, M.H.

    2015-01-01

    Objectives To assess the diagnostic value of multiparametric-MRI (MPMRI) with hypoxia imaging as a functional marker for characterizing and detecting vaginal vault/local recurrence following primary surgery for cervical cancer. Methods With institutional review board approval and written informed consent 30 women (median age: 45 years) from October 2009 to March 2010 with previous operated carcinoma cervix and suspected clinical vaginal vault/local recurrence were examined with 3.0T-MRI. MRI imaging included conventional and MPMRI sequences [dynamic contrast enhanced (DCE), diffusion weighted (DW), 1H-MR spectroscopy (1HMRS), blood oxygen level dependent hypoxia imaging (BOLD)]. Two radiologists, blinded to pathologic findings, independently assessed the pretherapy MRI findings and then correlated it with histopathology findings. Sensitivity, specificity, positive predictive value, negative predictive value and their confidence intervals were calculated. The pre and post therapy conventional and MPMRI parameters were analyzed and correlated with response to therapy. Results Of the 30 patients, there were 24 recurrent tumors and 6 benign lesions. The accuracy of diagnosing recurrent vault lesions was highest at combined MPMRI and conventional MRI (100%) than at conventional-MRI (70%) or MPMRI (96.7%) alone. Significant correlation was seen between percentage tumor regression and pre-treatment parameters such as negative enhancement integral (NEI) (p = 0.02), the maximum slope (p = 0.04), mADC value (p = 0.001) and amount of hypoxic fraction on the pretherapy MRI (p = 0.01). Conclusion Conventional-MR with MPMRI significantly increases the diagnostic accuracy for suspected vaginal vault/local recurrence. Post therapy serial MPMRI with hypoxia imaging follow-up objectively documents the response. MPMRI and BOLD hypoxia imaging provide information regarding tumor biology at the molecular, subcellular, cellular and tissue levels and this information may be used

  9. Image responses to x-ray radiation in ICCD camera

    NASA Astrophysics Data System (ADS)

    Ma, Jiming; Duan, Baojun; Song, Yan; Song, Guzhou; Han, Changcai; Zhou, Ming; Du, Jiye; Wang, Qunshu; Zhang, Jianqi

    2013-08-01

    When used in digital radiography, ICCD camera will be inevitably irradiated by x-ray and the output image will degrade. In this research, we separated ICCD camera into two optical-electric parts, CCD camera and MCP image intensifier, and irradiated them respectively on Co-60 gamma ray source and pulsed x-ray source. By changing time association between radiation and the shutter of CCD camera, the state of power supply of MCP image intensifier, significant differences have been observed in output images. A further analysis has revealed the influence of the CCD chip, readout circuit in CCD camera, and the photocathode, microchannel plate and fluorescent screen in MCP image intensifier on image quality of an irradiated ICCD camera. The study demonstrated that compared with other parts, irradiation response of readout circuit is very slight and in most cases negligible. The interaction of x-ray with CCD chip usually behaves as bright spots or rough background in output images, which depends on x-ray doses. As to the MCP image intensifier, photocathode and microchannel plate are the two main steps that degrade output images. When being irradiated by x-ray, microchannel plate in MCP image intensifier tends to contribute a bright background in output images. Background caused by the photocathode looks more bright and fluctuant. Image responses of fluorescent screen in MCP image intensifier in ICCD camera and that of a coupling fiber bundle are also evaluated in this presentation.

  10. Evaluation of 3D imaging.

    PubMed

    Vannier, M W

    2000-10-01

    Interactive computer-based simulation is gaining acceptance for craniofacial surgical planning. Subjective visualization without objective measurement capability, however, severely limits the value of simulation since spatial accuracy must be maintained. This study investigated the error sources involved in one method of surgical simulation evaluation. Linear and angular measurement errors were found to be within +/- 1 mm and 1 degree. Surface match of scanned objects was slightly less accurate, with errors up to 3 voxels and 4 degrees, and Boolean subtraction methods were 93 to 99% accurate. Once validated, these testing methods were applied to objectively compare craniofacial surgical simulations to post-operative outcomes, and verified that the form of simulation used in this study yields accurate depictions of surgical outcome. However, to fully evaluate surgical simulation, future work is still required to test the new methods in sufficient numbers of patients to achieve statistically significant results. Once completely validated, simulation cannot only be used in pre-operative surgical planning, but also as a post-operative descriptor of surgical and traumatic physical changes. Validated image comparison methods can also show discrepancy of surgical outcome to surgical plan, thus allowing evaluation of surgical technique. PMID:11098409

  11. Image analysis of neuropsychological test responses

    NASA Astrophysics Data System (ADS)

    Smith, Stephen L.; Hiller, Darren L.

    1996-04-01

    This paper reports recent advances in the development of an automated approach to neuropsychological testing. High performance image analysis algorithms have been developed as part of a convenient and non-invasive computer-based system to provide an objective assessment of patient responses to figure-copying tests. Tests of this type are important in determining the neurological function of patients following stroke through evaluation of their visuo-spatial performance. Many conventional neuropsychological tests suffer from the serious drawback that subjective judgement on the part of the tester is required in the measurement of the patient's response which leads to a qualitative neuropsychological assessment that can be both inconsistent and inaccurate. Results for this automated approach are presented for three clinical populations: patients suffering right hemisphere stroke are compared with adults with no known neurological disorder and a population comprising normal school children of 11 years is presented to demonstrate the sensitivity of the technique. As well as providing a more reliable and consistent diagnosis this technique is sufficiently sensitive to monitor a patient's progress over a period of time and will provide the neuropsychologist with a practical means of evaluating the effectiveness of therapy or medication administered as part of a rehabilitation program.

  12. Non-Hodgkin lymphoma response evaluation with MRI texture classification

    PubMed Central

    Harrison, Lara CV; Luukkaala, Tiina; Pertovaara, Hannu; Saarinen, Tuomas O; Heinonen, Tomi T; Järvenpää, Ritva; Soimakallio, Seppo; Kellokumpu-Lehtinen, Pirkko-Liisa I; Eskola, Hannu J; Dastidar, Prasun

    2009-01-01

    Background To show magnetic resonance imaging (MRI) texture appearance change in non-Hodgkin lymphoma (NHL) during treatment with response controlled by quantitative volume analysis. Methods A total of 19 patients having NHL with an evaluable lymphoma lesion were scanned at three imaging timepoints with 1.5T device during clinical treatment evaluation. Texture characteristics of images were analyzed and classified with MaZda application and statistical tests. Results NHL tissue MRI texture imaged before treatment and under chemotherapy was classified within several subgroups, showing best discrimination with 96% correct classification in non-linear discriminant analysis of T2-weighted images. Texture parameters of MRI data were successfully tested with statistical tests to assess the impact of the separability of the parameters in evaluating chemotherapy response in lymphoma tissue. Conclusion Texture characteristics of MRI data were classified successfully; this proved texture analysis to be potential quantitative means of representing lymphoma tissue changes during chemotherapy response monitoring. PMID:19545438

  13. Anniversary paper: evaluation of medical imaging systems.

    PubMed

    Krupinski, Elizabeth A; Jiang, Yulei

    2008-02-01

    Medical imaging used to be primarily within the domain of radiology, but with the advent of virtual pathology slides and telemedicine, imaging technology is expanding in the healthcare enterprise. As new imaging technologies are developed, they must be evaluated to assess the impact and benefit on patient care. The authors review the hierarchical model of the efficacy of diagnostic imaging systems by Fryback and Thornbury [Med. Decis. Making 11, 88-94 (1991)] as a guiding principle for system evaluation. Evaluation of medical imaging systems encompasses everything from the hardware and software used to acquire, store, and transmit images to the presentation of images to the interpreting clinician. Evaluation of medical imaging systems can take many forms, from the purely technical (e.g., patient dose measurement) to the increasingly complex (e.g., determining whether a new imaging method saves lives and benefits society). Evaluation methodologies cover a broad range, from receiver operating characteristic (ROC) techniques that measure diagnostic accuracy to timing studies that measure image-interpretation workflow efficiency. The authors review briefly the history of the development of evaluation methodologies and review ROC methodology as well as other types of evaluation methods. They discuss unique challenges in system evaluation that face the imaging community today and opportunities for future advances. PMID:18383686

  14. On the response function separability of hyperspectral imaging systems

    NASA Astrophysics Data System (ADS)

    Jemec, Jurij; Pernuš, Franjo; Likar, Boštjan; Bürmen, Miran

    2015-05-01

    Hyperspectral imaging systems effectively collect information across the spectral and two spatial dimensions by employing three main components: the front lens, the light-diffraction element and a camera. Imperfections in these components introduce spectral and spatial dependent distortions in the recorded hyperspectral image. These can be characterized by a 3D response function that is subsequently used to remove distortions and enhance the resolution of the recorded images by deconvolution. The majority of existing characterization methods assume spatial and spectral separability of the 3D response function. In this way, the complex problem of 3D response function characterization is reduced to independent characterizations of the three orthogonal response function components. However, if the 3D response function is non-separable, such characterization can lead to poor response function estimates, and hence inaccurate and distorted results of the subsequent deconvolution-based calibration and image enhancement. In this paper, we evaluate the influence of the spatial response function non-separability on the results of the calibration by deconvolution. For this purpose, a novel procedure for direct measurement of the 2D spatial response function is proposed along with a quantitative measure of the spatial response function non-separability. The quality of deconvolved images is assessed in terms of full width at half maximum (FWHM) and step edge overshoot magnitude observed in the deconvolved images of slanted edges, images of biological slides, and 1951 USAF resolution test chart. Results show that there are cases, when nonseparability of the system response function is significant and should be considered by the deconvolution-based calibration and image enhancement methods.

  15. Assessment of tumor response on MR imaging after locoregional therapy.

    PubMed

    Vossen, Josephina A; Buijs, Manon; Kamel, Ihab R

    2006-09-01

    Assessment of tumor response after locoregional therapies is important in determining treatment success and in guiding future therapy. Magnetic resonance imaging plays an important role in evaluating treatment response to new therapies directed toward hepatic lesion treatment. The traditional and accepted criteria to determine tumor response in oncology, namely the Response Evaluation Criteria in Solid Tumors (RECIST) and the European Association for the Study of the Liver (EASL) criteria, use decrease in tumor size and lesion enhancement as an indicator of successful therapy. A more recent evaluation method is the Apparent Diffusion Coefficient (ADC) measured by diffusion-weighted MR imaging. Diffusion-weighted MR imaging and ADC values map the thermally induced motion of water molecules in tissues and thereby are able to provide insight into tumor microstructure. In this article we discuss the role of MR imaging in assessing treatment response after various locoregional therapies. We describe the role of tumor size and lesion enhancement as well as ADC mapping. We also discuss the magnetic resonance imaging findings after radiofrequency ablation (RFA), transarterial chemoembolization (TACE) and radioembolization. PMID:17561215

  16. The Temperature Response of EUV Imagers

    NASA Astrophysics Data System (ADS)

    Raftery, Claire; Bloomfield, D. Shaun; Gallagher, P.

    2009-05-01

    The temperature response of an EUV imager provides the user with the temperature range over which the instrument or passband is sensitive. These response curves appear to be highly peaked, implying a narrow range of temperature sensitivity. However, in the past, these response functions have been calculated using quiet sun spectra or constant density, assumptions which are relevant only in specific circumstances. The multithermal response of the EUV imagers - TRACE, SOHO/EIT, STEREO/EUVI, PROBA2/SWAP and SDO/AIA were investigated. It was found that a highly peaked response curve is only appropriate when looking at cooler material. However, studying higher temperature emission from e.g. active regions and flares produces a very broad, almost flat response between 105 and 107 K for all instruments. CLR is supported by an SPD studentship and the ESA/Prodex grant administered by Enterprise Ireland.

  17. Evaluating Image Browsers Using Structured Annotation.

    ERIC Educational Resources Information Center

    Muller, Wolfgang; Marchand-Mailet, Stephane; Muller, Henning; Squire, David McG.; Pun, Thierry

    2001-01-01

    Addresses the problem of benchmarking image browsers. Existence of different search paradigms for image browsers makes it difficult to compare them. Currently, the only admissible evaluation method involves conducting large-scale user studies. An automatic image browser benchmark is proposed that uses structured text annotation of the image…

  18. An Underwater Color Image Quality Evaluation Metric.

    PubMed

    Yang, Miao; Sowmya, Arcot

    2015-12-01

    Quality evaluation of underwater images is a key goal of underwater video image retrieval and intelligent processing. To date, no metric has been proposed for underwater color image quality evaluation (UCIQE). The special absorption and scattering characteristics of the water medium do not allow direct application of natural color image quality metrics especially to different underwater environments. In this paper, subjective testing for underwater image quality has been organized. The statistical distribution of the underwater image pixels in the CIELab color space related to subjective evaluation indicates the sharpness and colorful factors correlate well with subjective image quality perception. Based on these, a new UCIQE metric, which is a linear combination of chroma, saturation, and contrast, is proposed to quantify the non-uniform color cast, blurring, and low-contrast that characterize underwater engineering and monitoring images. Experiments are conducted to illustrate the performance of the proposed UCIQE metric and its capability to measure the underwater image enhancement results. They show that the proposed metric has comparable performance to the leading natural color image quality metrics and the underwater grayscale image quality metrics available in the literature, and can predict with higher accuracy the relative amount of degradation with similar image content in underwater environments. Importantly, UCIQE is a simple and fast solution for real-time underwater video processing. The effectiveness of the presented measure is also demonstrated by subjective evaluation. The results show better correlation between the UCIQE and the subjective mean opinion score. PMID:26513783

  19. Hyperspectral imaging for nondestructive evaluation of tomatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Machine vision methods for quality and defect evaluation of tomatoes have been studied for online sorting and robotic harvesting applications. We investigated the use of a hyperspectral imaging system for quality evaluation and defect detection for tomatoes. Hyperspectral reflectance images were a...

  20. Evaluating Similarity Measures for Brain Image Registration

    PubMed Central

    Razlighi, Q. R.; Kehtarnavaz, N.; Yousefi, S.

    2013-01-01

    Evaluation of similarity measures for image registration is a challenging problem due to its complex interaction with the underlying optimization, regularization, image type and modality. We propose a single performance metric, named robustness, as part of a new evaluation method which quantifies the effectiveness of similarity measures for brain image registration while eliminating the effects of the other parts of the registration process. We show empirically that similarity measures with higher robustness are more effective in registering degraded images and are also more successful in performing intermodal image registration. Further, we introduce a new similarity measure, called normalized spatial mutual information, for 3D brain image registration whose robustness is shown to be much higher than the existing ones. Consequently, it tolerates greater image degradation and provides more consistent outcomes for intermodal brain image registration. PMID:24039378

  1. Image performance evaluation of a 3D surgical imaging platform

    NASA Astrophysics Data System (ADS)

    Petrov, Ivailo E.; Nikolov, Hristo N.; Holdsworth, David W.; Drangova, Maria

    2011-03-01

    The O-arm (Medtronic Inc.) is a multi-dimensional surgical imaging platform. The purpose of this study was to perform a quantitative evaluation of the imaging performance of the O-arm in an effort to understand its potential for future nonorthopedic applications. Performance of the reconstructed 3D images was evaluated, using a custom-built phantom, in terms of resolution, linearity, uniformity and geometrical accuracy. Both the standard (SD, 13 s) and high definition (HD, 26 s) modes were evaluated, with the imaging parameters set to image the head (120 kVp, 100 mAs and 150 mAs, respectively). For quantitative noise characterization, the images were converted to Hounsfield units (HU) off-line. Measurement of the modulation transfer function revealed a limiting resolution (at 10% level) of 1.0 mm-1 in the axial dimension. Image noise varied between 15 and 19 HU for the HD and SD modes, respectively. Image intensities varied linearly over the measured range, up to 1300 HU. Geometric accuracy was maintained in all three dimensions over the field of view. The present study has evaluated the performance characteristics of the O-arm, and demonstrates feasibility for use in interventional applications and quantitative imaging tasks outside those currently targeted by the manufacturer. Further improvements to the reconstruction algorithms may further enhance performance for lower-contrast applications.

  2. Electromagnetic Imaging Methods for Nondestructive Evaluation Applications

    PubMed Central

    Deng, Yiming; Liu, Xin

    2011-01-01

    Electromagnetic nondestructive tests are important and widely used within the field of nondestructive evaluation (NDE). The recent advances in sensing technology, hardware and software development dedicated to imaging and image processing, and material sciences have greatly expanded the application fields, sophisticated the systems design and made the potential of electromagnetic NDE imaging seemingly unlimited. This review provides a comprehensive summary of research works on electromagnetic imaging methods for NDE applications, followed by the summary and discussions on future directions. PMID:22247693

  3. Unsupervised Performance Evaluation of Image Segmentation

    NASA Astrophysics Data System (ADS)

    Chabrier, Sebastien; Emile, Bruno; Rosenberger, Christophe; Laurent, Helene

    2006-12-01

    We present in this paper a study of unsupervised evaluation criteria that enable the quantification of the quality of an image segmentation result. These evaluation criteria compute some statistics for each region or class in a segmentation result. Such an evaluation criterion can be useful for different applications: the comparison of segmentation results, the automatic choice of the best fitted parameters of a segmentation method for a given image, or the definition of new segmentation methods by optimization. We first present the state of art of unsupervised evaluation, and then, we compare six unsupervised evaluation criteria. For this comparative study, we use a database composed of 8400 synthetic gray-level images segmented in four different ways. Vinet's measure (correct classification rate) is used as an objective criterion to compare the behavior of the different criteria. Finally, we present the experimental results on the segmentation evaluation of a few gray-level natural images.

  4. 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.

  5. Changing CS Features Alters Evaluative Responses in Evaluative Conditioning

    ERIC Educational Resources Information Center

    Unkelbach, Christian; Stahl, Christoph; Forderer, Sabine

    2012-01-01

    Evaluative conditioning (EC) refers to changes in people's evaluative responses toward initially neutral stimuli (CSs) by mere spatial and temporal contiguity with other positive or negative stimuli (USs). We investigate whether changing CS features from conditioning to evaluation also changes people's evaluative response toward these CSs. We used…

  6. Performance evaluation of image segmentation algorithms on microscopic image data.

    PubMed

    Beneš, Miroslav; Zitová, Barbara

    2015-01-01

    In our paper, we present a performance evaluation of image segmentation algorithms on microscopic image data. In spite of the existence of many algorithms for image data partitioning, there is no universal and 'the best' method yet. Moreover, images of microscopic samples can be of various character and quality which can negatively influence the performance of image segmentation algorithms. Thus, the issue of selecting suitable method for a given set of image data is of big interest. We carried out a large number of experiments with a variety of segmentation methods to evaluate the behaviour of individual approaches on the testing set of microscopic images (cross-section images taken in three different modalities from the field of art restoration). The segmentation results were assessed by several indices used for measuring the output quality of image segmentation algorithms. In the end, the benefit of segmentation combination approach is studied and applicability of achieved results on another representatives of microscopic data category - biological samples - is shown. PMID:25233873

  7. Evaluation of Carotid Plaque Using Ultrasound Imaging

    PubMed Central

    2016-01-01

    Traditional risk factors for predicting of cardiovascular disease are not always effective predictors for development of cardiovascular events. This review summarizes several newly developed noninvasive imaging techniques for evaluating carotid plaques and their role in cardiovascular disease risk. PMID:27358696

  8. Aligning Collaborative and Culturally Responsive Evaluation Approaches

    ERIC Educational Resources Information Center

    Askew, Karyl; Beverly, Monifa Green; Jay, Michelle L.

    2012-01-01

    The authors, three African-American women trained as collaborative evaluators, offer a comparative analysis of collaborative evaluation (O'Sullivan, 2004) and culturally responsive evaluation approaches (Frierson, Hood, & Hughes, 2002; Kirkhart & Hopson, 2010). Collaborative evaluation techniques immerse evaluators in the cultural milieu of the…

  9. Improving Beta Test Evaluation Response Rates: A Meta-Evaluation

    ERIC Educational Resources Information Center

    Russ-Eft, Darlene; Preskill, Hallie

    2005-01-01

    This study presents a meta-evaluation of a beta-test of a customer service training program. The initial evaluation showed a low response rate. Therefore, the meta-evaluation focused on issues related to the conduct of the initial evaluation and reasons for nonresponse. The meta-evaluation identified solutions to the nonresponse problem as related…

  10. Pork grade evaluation using hyperspectral imaging techniques

    NASA Astrophysics Data System (ADS)

    Zhou, Rui; Cai, Bo; Wang, Shoubing; Ji, Huihua; Chen, Huacai

    2011-11-01

    The method to evaluate the grade of the pork based on hyperspectral imaging techniques was studied. Principal component analysis (PCA) was performed on the hyperspectral image data to extract the principal components which were used as the inputs of the evaluation model. By comparing the different discriminating rates in the calibration set and the validation set under different information, the choice of the components can be optimized. Experimental results showed that the classification evaluation model was the optimal when the principal of component (PC) of spectra was 3, while the corresponding discriminating rate was 89.1% in the calibration set and 84.9% in the validation set. It was also good when the PC of images was 9, while the corresponding discriminating rate was 97.2% in the calibration set and 91.1% in the validation set. The evaluation model based on both information of spectra and images was built, in which the corresponding PCs of spectra and images were used as the inputs. This model performed very well in grade classification evaluation, and the discriminating rates of calibration set and validation set were 99.5% and 92.7%, respectively, which were better than the two evaluation models based on single information of spectra or images.

  11. Image quality evaluation using moving targets

    NASA Astrophysics Data System (ADS)

    Artmann, Uwe

    2013-03-01

    The basic concept of testing a digital imaging device is to reproduce a known target and to analyze the resulting image. This semi-reference approach can be used for various different aspects of image quality. Each part of the imaging chain can have an influence on the results: lens, sensor, image processing and the target itself. The results are valid only for the complete system. If we want to test a single component, we have to make sure that we change only one and keep all others constant. When testing mobile imaging devices, we run into the problem that hardly anything can be manually controlled by the tester. Manual exposure control is not available for most devices, the focus cannot be influenced and hardly any settings for the image processing are available. Due to the limitations in the hardware, the image pipeline in the digital signal processor (DSP) of mobile imaging devices is a critical part of the image quality evaluation. The processing power of the DSPs allows sharpening, tonal correction and noise reduction to be non-linear and adaptive. This makes it very hard to describe the behavior for an objective image quality evaluation. The image quality is highly influenced by the signal processing for noise and resolution and the processing is the main reason for the loss of low contrast, _ne details, the so called texture blur. We present our experience to describe the image processing in more detail. All standardized test methods use a defined chart and require, that the chart and the camera are not moved in any way during test. In this paper, we present our results investigating the influence of chart movement during the test. Different structures, optimized for different aspects of image quality evaluation, are moved with a defined speed during the capturing process. The chart movement will change the input for the signal processing depending on the speed of the target during the test. The basic theoretical changes in the image will be the

  12. The Practice and Politics of Responsive Evaluation

    ERIC Educational Resources Information Center

    Abma, Tineke

    2006-01-01

    Responsive evaluation offers a perspective in which evaluation is reframed from the assessment of program interventions on the basis of policy makers' goals to an engagement with and among all stakeholders about the value and meaning of their practice. Responsive evaluators have to be extra sensitive to power relations given the deliberate…

  13. Evaluation of allergic response using dynamic thermography

    NASA Astrophysics Data System (ADS)

    Rokita, E.; Rok, T.; Tatoń, G.

    2015-03-01

    Skin dynamic termography supplemented by a mathematical model is presented as an objective and sensitive indicator of the skin prick test result. Termographic measurements were performed simultaneously with routine skin prick tests. The IR images were acquired every 70 s up to 910 s after skin prick. In the model histamine is treated as the principal mediator of the allergic reaction. Histamine produces vasolidation and the engorged vessels are responsible for an increase in skin temperature. The model parameters were determined by fitting the analytical solutions to the spatio-temporal distributions of the differences between measured and baseline temperatures. The model reproduces experimental data very well (coefficient of determination = 0.805÷0.995). The method offers a set of parameters to describe separately skin allergic reaction and skin reactivity. The release of histamine after allergen injection is the best indicator of allergic response. The diagnostic parameter better correlates with the standard evaluation of a skin prick test (correlation coefficient = 0.98) than the result of the thermographic planimetric method based on temperature and heated area determination (0.81). The high sensitivity of the method allows for determination of the allergic response in patients with the reduced skin reactivity.

  14. Computerized scheme for evaluating mammographic phantom images

    SciTech Connect

    Asahara, Masaki; Kodera, Yoshie

    2012-03-15

    Purpose: The authors developed a computer algorithm to automatically evaluate images of the American College of Radiology (ACR) mammography accreditation phantom. Methods: The developed algorithm consist of the edge detection of wax insert, nonuniformity correction of background, and correction for magnification and also calculate the cross-correlation coefficient by image matching technique. The algorithm additionally evaluates target shape for fibers, target contrast for speck groups, and target circularity for masses. To obtain an ideal template image without noise and spatial resolution loss, the wax insert containing the embedded test pattern was extracted from the phantom and radiographed. Two template images and ten test phantom images were prepared for this study. The results of evaluation using the algorithm outputs were compared with the averaged results of observer studies by six skilled observers. Results: In comparing the results from the algorithm outputs with the results of observers, the authors found that the computer outputs were well correlated with the evaluations by observers, and they indicate the quality of the phantom image. The correlation coefficients between results of observer studies and two outputs of computer algorithm, i.e., the cross-correlation coefficient by template matching and indices of target shape for fibers, were 0.89 (95% confidence interval, 0.82-0.93; hereinafter the same) and 0.85 (0.76-0.91). The correlation coefficients between observer's results and two outputs: the cross-correlation coefficient and indices of target contrast for speck groups, were 0.83 (0.79-0.86) and 0.85 (0.81-0.88) and between observer's results and two outputs: the cross-correlation coefficient and indices of target circularity for masses, were 0.90 (0.84-0.94) and 0.87 (0.77-0.92). Conclusions: Image evaluation using the ACR phantom is indispensable in quality control of a mammography system. The proposed algorithm is useful for quality control

  15. They Can Communicate: Self-Image Evaluation.

    ERIC Educational Resources Information Center

    Deschin, Celia S.

    As part of a 2 year demonstration project to evaluate the effect on the mental health of physically handicapped children placed in organized group activities with their nonhandicapped peers, two research instruments were used. The monograph discusses one of the instruments, the Self-Image Evaluation. A synopsis of the project is provided; and a…

  16. Accuracy test procedure for image evaluation techniques.

    PubMed

    Jones, R A

    1968-01-01

    A procedure has been developed to determine the accuracy of image evaluation techniques. In the procedure, a target having orthogonal test arrays is photographed with a high quality optical system. During the exposure, the target is subjected to horizontal linear image motion. The modulation transfer functions of the images in the horizontal and vertical directions are obtained using the evaluation technique. Since all other degradations are symmetrical, the quotient of the two modulation transfer functions represents the modulation transfer function of the experimentally induced linear image motion. In an accurate experiment, any discrepancy between the experimental determination and the true value is due to inaccuracy in the image evaluation technique. The procedure was used to test the Perkin-Elmer automated edge gradient analysis technique over the spatial frequency range of 0-200 c/m. This experiment demonstrated that the edge gradient technique is accurate over this region and that the testing procedure can be controlled with the desired accuracy. Similarly, the test procedure can be used to determine the accuracy of other image evaluation techniques. PMID:20062421

  17. Color image processing for date quality evaluation

    NASA Astrophysics Data System (ADS)

    Lee, Dah Jye; Archibald, James K.

    2010-01-01

    Many agricultural non-contact visual inspection applications use color image processing techniques because color is often a good indicator of product quality. Color evaluation is an essential step in the processing and inventory control of fruits and vegetables that directly affects profitability. Most color spaces such as RGB and HSV represent colors with three-dimensional data, which makes using color image processing a challenging task. Since most agricultural applications only require analysis on a predefined set or range of colors, mapping these relevant colors to a small number of indexes allows simple and efficient color image processing for quality evaluation. This paper presents a simple but efficient color mapping and image processing technique that is designed specifically for real-time quality evaluation of Medjool dates. In contrast with more complex color image processing techniques, the proposed color mapping method makes it easy for a human operator to specify and adjust color-preference settings for different color groups representing distinct quality levels. Using this color mapping technique, the color image is first converted to a color map that has one color index represents a color value for each pixel. Fruit maturity level is evaluated based on these color indices. A skin lamination threshold is then determined based on the fruit surface characteristics. This adaptive threshold is used to detect delaminated fruit skin and hence determine the fruit quality. The performance of this robust color grading technique has been used for real-time Medjool date grading.

  18. Digital image envelope: method and evaluation

    NASA Astrophysics Data System (ADS)

    Huang, H. K.; Cao, Fei; Zhou, Michael Z.; Mogel, Greg T.; Liu, Brent J.; Zhou, Xiaoqiang

    2003-05-01

    Health data security, characterized in terms of data privacy, authenticity, and integrity, is a vital issue when digital images and other patient information are transmitted through public networks in telehealth applications such as teleradiology. Mandates for ensuring health data security have been extensively discussed (for example The Health Insurance Portability and Accountability Act, HIPAA) and health informatics guidelines (such as the DICOM standard) are beginning to focus on issues of data continue to be published by organizing bodies in healthcare; however, there has not been a systematic method developed to ensure data security in medical imaging Because data privacy and authenticity are often managed primarily with firewall and password protection, we have focused our research and development on data integrity. We have developed a systematic method of ensuring medical image data integrity across public networks using the concept of the digital envelope. When a medical image is generated regardless of the modality, three processes are performed: the image signature is obtained, the DICOM image header is encrypted, and a digital envelope is formed by combining the signature and the encrypted header. The envelope is encrypted and embedded in the original image. This assures the security of both the image and the patient ID. The embedded image is encrypted again and transmitted across the network. The reverse process is performed at the receiving site. The result is two digital signatures, one from the original image before transmission, and second from the image after transmission. If the signatures are identical, there has been no alteration of the image. This paper concentrates in the method and evaluation of the digital image envelope.

  19. A Ranking Method for Evaluating Constructed Responses

    ERIC Educational Resources Information Center

    Attali, Yigal

    2014-01-01

    This article presents a comparative judgment approach for holistically scored constructed response tasks. In this approach, the grader rank orders (rather than rate) the quality of a small set of responses. A prior automated evaluation of responses guides both set formation and scaling of rankings. Sets are formed to have similar prior scores and…

  20. 19F Magnetic Resonance Imaging of Perfluorocarbons for the Evaluation of Response to Antibiotic Therapy in a Staphylococcus aureus Infection Model

    PubMed Central

    Jakob, Peter; Ohlsen, Knut

    2013-01-01

    Background The emergence of antibiotic resistant bacteria in recent decades has highlighted the importance of developing new drugs to treat infections. However, in addition to the design of new drugs, the development of accurate preclinical testing methods is essential. In vivo imaging technologies such as bioluminescence imaging (BLI) or magnetic resonance imaging (MRI) are promising approaches. In a previous study, we showed the effectiveness of 19F MRI using perfluorocarbon (PFC) emulsions for detecting the site of Staphylococcus aureus infection. In the present follow-up study, we investigated the use of this method for in vivo visualization of the effects of antibiotic therapy. Methods/Principal findings Mice were infected with S. aureus Xen29 and treated with 0.9% NaCl solution, vancomycin or linezolid. Mock treatment led to the highest bioluminescence values during infection followed by vancomycin treatment. Counting the number of colony-forming units (cfu) at 7 days post-infection (p.i.) showed the highest bacterial burden for the mock group and the lowest for the linezolid group. Administration of PFCs at day 2 p.i. led to the accumulation of 19F at the rim of the abscess in all mice (in the shape of a hollow sphere), and antibiotic treatment decreased the 19F signal intensity and volume. Linezolid showed the strongest effect. The BLI, cfu, and MRI results were comparable. Conclusions 19F-MRI with PFCs is an effective non-invasive method for assessing the effects of antibiotic therapy in vivo. This method does not depend on pathogen specific markers and can therefore be used to estimate the efficacy of antibacterial therapy against a broad range of clinically relevant pathogens, and to localize sites of infection. PMID:23724049

  1. Evaluating fusion techniques for multi-sensor satellite image data

    SciTech Connect

    Martin, Benjamin W; Vatsavai, Raju

    2013-01-01

    Satellite image data fusion is a topic of interest in many areas including environmental monitoring, emergency response, and defense. Typically any single satellite sensor cannot provide all of the benefits offered by a combination of different sensors (e.g., high-spatial but low spectral resolution vs. low-spatial but high spectral, optical vs. SAR). Given the respective strengths and weaknesses of the different types of image data, it is beneficial to fuse many types of image data to extract as much information as possible from the data. Our work focuses on the fusion of multi-sensor image data into a unified representation that incorporates the potential strengths of a sensor in order to minimize classification error. Of particular interest is the fusion of optical and synthetic aperture radar (SAR) images into a single, multispectral image of the best possible spatial resolution. We explore various methods to optimally fuse these images and evaluate the quality of the image fusion by using K-means clustering to categorize regions in the fused images and comparing the accuracies of the resulting categorization maps.

  2. Image Inpainting Methods Evaluation and Improvement

    PubMed Central

    Vreja, Raluca

    2014-01-01

    With the upgrowing of digital processing of images and film archiving, the need for assisted or unsupervised restoration required the development of a series of methods and techniques. Among them, image inpainting is maybe the most impressive and useful. Based on partial derivative equations or texture synthesis, many other hybrid techniques have been proposed recently. The need for an analytical comparison, beside the visual one, urged us to perform the studies shown in the present paper. Starting with an overview of the domain, an evaluation of the five methods was performed using a common benchmark and measuring the PSNR. Conclusions regarding the performance of the investigated algorithms have been presented, categorizing them in function of the restored image structure. Based on these experiments, we have proposed an adaptation of Oliveira's and Hadhoud's algorithms, which are performing well on images with natural defects. PMID:25136700

  3. Image inpainting methods evaluation and improvement.

    PubMed

    Vreja, Raluca; Brad, Remus

    2014-01-01

    With the upgrowing of digital processing of images and film archiving, the need for assisted or unsupervised restoration required the development of a series of methods and techniques. Among them, image inpainting is maybe the most impressive and useful. Based on partial derivative equations or texture synthesis, many other hybrid techniques have been proposed recently. The need for an analytical comparison, beside the visual one, urged us to perform the studies shown in the present paper. Starting with an overview of the domain, an evaluation of the five methods was performed using a common benchmark and measuring the PSNR. Conclusions regarding the performance of the investigated algorithms have been presented, categorizing them in function of the restored image structure. Based on these experiments, we have proposed an adaptation of Oliveira's and Hadhoud's algorithms, which are performing well on images with natural defects. PMID:25136700

  4. Imaging for assessment of treatment response in hepatocellular carcinoma: Current update

    PubMed Central

    Hayano, Koichi; Lee, Sang Ho; Sahani, Dushyant V

    2015-01-01

    Morphologic methods such as the Response Evaluation Criteria in Solid Tumors (RECIST) are considered as the gold standard for response assessment in the management of cancer. However, with the increasing clinical use of antineoplastic cytostatic agents and locoregional interventional therapies in hepatocellular carcinoma (HCC), conventional morphologic methods are confronting limitations in response assessment. Thus, there is an increasing interest in new imaging methods for response assessment, which can evaluate tumor biology such as vascular physiology, fibrosis, necrosis, and metabolism. In this review, we discuss various novel imaging methods for response assessment and compare them with the conventional ones in HCC. PMID:25969635

  5. Performance evaluation of a biometric system based on acoustic images.

    PubMed

    Izquierdo-Fuente, Alberto; del Val, Lara; Jiménez, María I; Villacorta, Juan J

    2011-01-01

    An acoustic electronic scanning array for acquiring images from a person using a biometric application is developed. Based on pulse-echo techniques, multifrequency acoustic images are obtained for a set of positions of a person (front, front with arms outstretched, back and side). Two Uniform Linear Arrays (ULA) with 15 λ/2-equispaced sensors have been employed, using different spatial apertures in order to reduce sidelobe levels. Working frequencies have been designed on the basis of the main lobe width, the grating lobe levels and the frequency responses of people and sensors. For a case-study with 10 people, the acoustic profiles, formed by all images acquired, are evaluated and compared in a mean square error sense. Finally, system performance, using False Match Rate (FMR)/False Non-Match Rate (FNMR) parameters and the Receiver Operating Characteristic (ROC) curve, is evaluated. On the basis of the obtained results, this system could be used for biometric applications. PMID:22163708

  6. Performance Evaluation of a Biometric System Based on Acoustic Images

    PubMed Central

    Izquierdo-Fuente, Alberto; del Val, Lara; Jiménez, María I.; Villacorta, Juan J.

    2011-01-01

    An acoustic electronic scanning array for acquiring images from a person using a biometric application is developed. Based on pulse-echo techniques, multifrequency acoustic images are obtained for a set of positions of a person (front, front with arms outstretched, back and side). Two Uniform Linear Arrays (ULA) with 15 λ/2-equispaced sensors have been employed, using different spatial apertures in order to reduce sidelobe levels. Working frequencies have been designed on the basis of the main lobe width, the grating lobe levels and the frequency responses of people and sensors. For a case-study with 10 people, the acoustic profiles, formed by all images acquired, are evaluated and compared in a mean square error sense. Finally, system performance, using False Match Rate (FMR)/False Non-Match Rate (FNMR) parameters and the Receiver Operating Characteristic (ROC) curve, is evaluated. On the basis of the obtained results, this system could be used for biometric applications. PMID:22163708

  7. [Health economic evaluation of AIDS response].

    PubMed

    Sun, Jiangping

    2015-06-01

    During the past over 20 years of AIDS response in China, different fields from the international society and domestic sources provide significant amounts of resources for China's AIDS response. The investment, distribution and use of these resources and their effect has become the concern of the society. The health economic evaluation method is used to scientifically answer these questions, which is also the motivation of the evaluation studies. Based on several studies on health economic evaluation of AIDS response in this issue, concepts and issues related to this area are summarized. It is important for the readers to make a point of health economics evaluation, and it is also of great importance to know its limitations to provide the basis for future proper use of AIDS health economic evaluation results. PMID:26310326

  8. (18)F-FDG-PET/CT imaging in an IL-6- and MYC-driven mouse model of human multiple myeloma affords objective evaluation of plasma cell tumor progression and therapeutic response to the proteasome inhibitor ixazomib.

    PubMed

    Duncan, K; Rosean, T R; Tompkins, V S; Olivier, A; Sompallae, R; Zhan, F; Tricot, G; Acevedo, M R; Ponto, L L B; Walsh, S A; Tygrett, L T; Berger, A J; Waldschmidt, T; Morse, H C; Sunderland, J J; Janz, S

    2013-01-01

    (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) and computed tomography (CT) are useful imaging modalities for evaluating tumor progression and treatment responses in genetically engineered mouse models of solid human cancers, but the potential of integrated FDG-PET/CT for assessing tumor development and new interventions in transgenic mouse models of human blood cancers such as multiple myeloma (MM) has not been demonstrated. Here we use BALB/c mice that contain the newly developed iMyc(ΔEμ) gene insertion and the widely expressed H2-L(d)-IL6 transgene to demonstrate that FDG-PET/CT affords an excellent research tool for assessing interleukin-6- and MYC-driven plasma cell tumor (PCT) development in a serial, reproducible and stage- and lesion-specific manner. We also show that FDG-PET/CT permits determination of objective drug responses in PCT-bearing mice treated with the investigational proteasome inhibitor ixazomib (MLN2238), the biologically active form of ixazomib citrate (MLN9708), that is currently in phase 3 clinical trials in MM. Overall survival of 5 of 6 ixazomib-treated mice doubled compared with mice left untreated. One outlier mouse presented with primary refractory disease. Our findings demonstrate the utility of FDG-PET/CT for preclinical MM research and suggest that this method will play an important role in the design and testing of new approaches to treat myeloma. PMID:24292417

  9. Use of Responsive Evaluation in Statewide Program Evaluation

    ERIC Educational Resources Information Center

    Kalman, Marjorie

    1976-01-01

    A summer school program stressing basic skills for migrant children in a rural Illinois community was assessed according to Stake's responsive evaluation model. Informal communication, program activities, audience needs, and participant values were emphasized in this case study. This evaluation method provided useful information for the state's…

  10. Use of Responsive Evaluation in Statewide Program Evaluation.

    ERIC Educational Resources Information Center

    Kalman, Marjorie

    The objective of this paper is to discuss the utilization of Stake's theory of responsive evaluation by a unit in state government charged with the evaluation of the Illinois Migrant Program. Through interviews with state and local Title I staff, we were able to discover program purposes and concerns and to later conceptualize these concerns into…

  11. Current imaging strategies for the evaluation of uterine cervical cancer

    PubMed Central

    Bourgioti, Charis; Chatoupis, Konstantinos; Moulopoulos, Lia Angela

    2016-01-01

    Uterine cervical cancer still remains an important socioeconomic issue because it largely affects women of reproductive age. Prognosis is highly depended on extent of the disease at diagnosis and, therefore, accurate staging is crucial for optimal management. Cervical cancer is clinically staged, according to International Federation of Gynecology and Obstetrics guidelines, but, currently, there is increased use of cross sectional imaging modalities [computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography-CT (PET-CT)] for the study of important prognostic factors like tumor size, parametrial invasion, endocervical extension, pelvic side wall or adjacent/distal organs involvement and lymph node status. Imaging indications also include cervical cancer follow-up, evaluation of tumor response to treatment and selection of suitable candidates for less radical surgeries like radical trachelectomy for fertility preservation. The preferred imaging method for local cervical cancer evaluation is MRI; CT is equally effective for evaluation of extrauterine spread of the disease. PET-CT shows high diagnostic performance for the detection of tumor relapse and metastatic lymph nodes. The aim of this review is to familiarize radiologists with the MRI appearance of cervical carcinoma and to discuss the indications of cross sectional imaging during the course of the disease in patients with cervical carcinoma. PMID:27158421

  12. Evaluating alternative responses to safeguards alarms

    SciTech Connect

    Al-Ayat, R.A.; Judd, B.R.; McCord, R.K.

    1982-04-15

    This paper describes a quantitative approach to help evaluate and respond to safeguards alarms. These alarms may be generated internally by a facility's safeguards systems or externally by individuals claiming to have stolen special nuclear material (SNM). This approach can be used to identify the most likely cause of an alarm - theft, hoax, or error - and to evaluate alternative responses to alarms. Possible responses include conducting investigations, initiating measures to recover stolen SNM, and replying to external threats. Based on the results of each alarm investigation step, the evaluation revises the likelihoods of possible causes of an alarm, and uses this information to determine the optimal sequence of further responses. The choice of an optimal sequence of responses takes into consideration the costs and benefits of successful thefts or hoaxes. These results provide an analytical basis for setting priorities and developing contingency plans for responding to safeguards alarms.

  13. Image Evaluation For Sensor Performance Standards

    NASA Astrophysics Data System (ADS)

    Peck, Lorin C.

    1989-02-01

    The subject of imagery evaluation as it applies to electro-optical (EO) sensor performance testing standards is discussed. Some of the difficulties encountered in the development of these standards for the various aircraft Line Replaceable Units (LRUs) are listed. The use of system performance testing is regarded as a requirement for the depot maintenance program to insure the integrity of total system performance requirements for EO imaging systems such as the Advanced Tactical Air Reconnaissance System (ATARS). The necessity for tying NATO Essential Elements of Information (EEIs) together with Imagery Interpretation Rating Scale (IIRS) numbers is explained. The requirements for a field target suitable for EO imagery evaluation is explained.

  14. Comparative effectiveness of imaging modalities to determine metastatic breast cancer treatment response.

    PubMed

    Lee, Christoph I; Gold, Laura S; Nelson, Heidi D; Chou, Roger; Ramsey, Scott D; Sullivan, Sean D

    2015-02-01

    We performed a systematic review to address the comparative effectiveness of different imaging modalities in evaluating treatment response among metastatic breast cancer patients. We searched seven multidisciplinary electronic databases for relevant publications (January 2003-December 2013) and performed dual abstraction of details and results for all clinical studies that involved stage IV breast cancer patients and evaluated imaging for detecting treatment response. Among 159 citations reviewed, 17 single-institution, non-randomized, observational studies met our inclusion criteria. Several studies demonstrate that changes in PET/CT standard uptake values are associated with changes in tumor volume as determined by bone scan, MRI, and/or CT. However, no studies evaluated comparative test performance between modalities or determined relationships between imaging findings and subsequent clinical decisions. Evidence for imaging's effectiveness in determining treatment response among metastatic breast cancer patients is limited. More rigorous research is needed to address imaging's value in this patient population. PMID:25479913

  15. Hyperspectral and multispectral imaging for evaluating food safety and quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spectral imaging technologies have been developed rapidly during the past decade. This paper presents hyperspectral and multispectral imaging technologies in the area of food safety and quality evaluation, with an introduction, demonstration, and summarization of the spectral imaging techniques avai...

  16. Optical imaging predicts tumor response to anti-EGFR therapy

    PubMed Central

    Helman, Emily E; Newman, J Robert; Dean, Nichole R; Zhang, Wenyue; Zinn, Kurt R

    2010-01-01

    To evaluate cetuximab treatment in head and neck squamous cell carcinoma xenografts and cell lines, we investigated a preclinical model of head and neck squamous cell carcinoma. Head and neck squamous cell carcinoma cell lines SCC-1, FaDu, CAL27, UM-SCC-5 and UM-SCC-22A were used to generate subcutaneous flank xenografts in SCID mice. Mice were divided into control and cetuximab treatment groups, mice in the latter group received 250 µg cetuximab once weekly for four weeks. After completion of therapy, SCC-1 (p < 0.001), UM-SCC-5 (p < 0.001), UM-SCC-22A (p = 0.016) and FaDu (p = 0.007) tumors were significantly smaller than control, while CAL27 tumors were not different from controls (p = 0.90). Mice were systemically injected with 50 µg of the Cy5.5-cetuximab bioconjugate and imaged by stereomicroscopy to determine if tumor fluorescence predicted tumor response. Intact tumor fluorescence did not predict response. Tissue was harvested from untreated xenografts to evaluate ex vivo imaging. Cell lines were then evaluated in vitro for fluorescence imaging after Cy5.5-cetuximab bioconjugate labeling. The location of fluorescence observed in labeled cells was significantly different for cell lines that responded to treatment, relative to unresponsive cells. Tumors from cell lines that showed low internalized signal in vitro responded best to treatment with cetuximab. This preclinical model may aid in determining which cancer patients are best suited for cetuximab therapy. PMID:20505368

  17. A versatile nondestructive evaluation imaging workstation

    NASA Technical Reports Server (NTRS)

    Chern, E. James; Butler, David W.

    1994-01-01

    Ultrasonic C-scan and eddy current imaging systems are of the pointwise type evaluation systems that rely on a mechanical scanner to physically maneuver a probe relative to the specimen point by point in order to acquire data and generate images. Since the ultrasonic C-scan and eddy current imaging systems are based on the same mechanical scanning mechanisms, the two systems can be combined using the same PC platform with a common mechanical manipulation subsystem and integrated data acquisition software. Based on this concept, we have developed an IBM PC-based combined ultrasonic C-scan and eddy current imaging system. The system is modularized and provides capacity for future hardware and software expansions. Advantages associated with the combined system are: (1) eliminated duplication of the computer and mechanical hardware, (2) unified data acquisition, processing and storage software, (3) reduced setup time for repetitious ultrasonic and eddy current scans, and (4) improved system efficiency. The concept can be adapted to many engineering systems by integrating related PC-based instruments into one multipurpose workstation such as dispensing, machining, packaging, sorting, and other industrial applications.

  18. MRI for evaluation of treatment response in rectal cancer.

    PubMed

    Blazic, Ivana M; Campbell, Naomi M; Gollub, Marc J

    2016-08-01

    MRI plays an increasingly pivotal role in the clinical staging of rectal cancer in the baseline and post-treatment settings. An accurate evaluation of response to neoadjuvant treatment is crucial because of its major influence on patient management and quality of life. However, evaluation of treatment response is challenging for both imaging and clinical assessments owing to treatment-related inflammation and fibrosis. At one end of the spectrum are clinical yT4 rectal cancers, wherein precise post-treatment MRI evaluation of tumour spread is particularly important for avoiding unnecessary exenterative surgery. At the other extreme, for tumours with clinical near-complete response or clinical complete response to neoadjuvant treatment, less invasive treatment may be suitable instead of the standard surgical approach such as, for example, a "Watch and Wait" approach or perhaps local excision. Ideally, the goal of post-treatment MRI evaluation would be to identify these subgroups of patients so that they might be spared unnecessary surgical intervention. It is known that post-chemoradiation therapy restaging using conventional MR sequences is less accurate than baseline staging, particularly in confirming T0 disease, largely owing to the difficulty in distinguishing fibrosis, oedema and normal mucosa from small foci of residual tumour. However, there is a growing utilization of multiparametric MRI, which has superseded other types of evaluations and requires review and periodic re-evaluation. This commentary discusses the current status of multiparametric MRI in the post-treatment setting and the challenges facing imaging in general in the accurate determination of treatment response. PMID:27331883

  19. Measured responsivities of generation II and hybrid image intensifiers

    SciTech Connect

    Yates, G.J.; King, N.S.P.; Thomas, M.C.

    1995-07-01

    We have measured the absolute and coupled system responsivities of several image intensifier types at several wavelengths in the visible spectrum. Intensifiers characterized include microchannel plate (MCP) generation II proximity-focused and hybrid generation I/generation II electrostatic-focused designs. Configurations including single plate, double plate, nominal and high strip current MCPs, and standard S20 and super generation II enhanced S-20 photocathodes were evaluated. Absolute responsivity measurements were performed using NIST-traceable radiometry instrumentation. The normalized relative sensitivities and overall optical luminous gain performance provided by individual intensifiers when similarly coupled to either high resolution 10-bit RS-170 CCD or FPS cameras are presented along with their radiometric data.

  20. University Social Responsibility and Brand Image of Private Universities in Bangkok

    ERIC Educational Resources Information Center

    Plungpongpan, Jirawan; Tiangsoongnern, Leela; Speece, Mark

    2016-01-01

    Purpose: The purpose of this paper is to examine the effects of university social responsibility (USR) on the brand image of private universities in Thailand. Brand image is important for entry into the consideration set as prospective students evaluate options for university study. USR activities may be implicit or explicit, i.e., actively…

  1. Evaluation of imaging characteristics in CTDI phantom size on contrast imaging

    NASA Astrophysics Data System (ADS)

    Jeon, Pil-Hyun; Lee, Won-Hyung; Jeon, Seong-Su; Kim, Hee-Joung

    2015-03-01

    Recently, there have been several physics and clinical studies on the use of lower tube potentials in CT imaging, with the purpose of improving image quality or further reducing radiation dose. We investigated an experimental study using a series of different sized, polymethyl methacrylate (PMMA) phantoms, demonstrating the potential strategy for dose reduction and to distinguish component of plaque by imaging their energy responses using CT. We investigated the relationship between different sizes of cylinderic PMMA-equivalent phantoms with diameter of 12, 16, 20, 24, and 32 cm and used contrast at various tube voltages (80, 100, 120, and 140 kVp) using a 16-detector row CT scanner. The contrast represented CT numbers as different materials for the water, calcium chloride, and iodine. Phantom insertions also allow quantitative measures of image noise, contrast, contrast-to-noise ratio (CNR) and figure of merit (FOM). When evaluating FOM, it was found that the lower kVp provided the better CNR. An experimental study was performed to demonstrate reduced dose for both dose efficient and practical feasibility for different patient sizes and diagnostic tasks by relating achievable CNR and the volume CT dose index (CTDIvol). The use of spectra optimized to the specific application could provide further improvements of distinguishing iodine, calcium and plaque component for patient size. The purpose of this study was to evaluate variations in image noise and contrast using different tube potentials in a CTDI phantom on contrast imaging.

  2. EVALUATION OF THIRTEEN SPILL RESPONSE TECHNOLOGIES

    EPA Science Inventory

    Thirteen spill response devices, concepts, or prototypes, developed under previous contracts to the U.S. Environmental Protection Agency for detection, containment, and cleanup of chemicals, were evaluated by potential users and manufacturers. The main goal of the project was to ...

  3. An Album of Response: Reflecting on the Images.

    ERIC Educational Resources Information Center

    Mathis, Janelle B.

    2002-01-01

    Offers five "images" (personal recollections) of reader response in the life of the author/educator. Suggests that while each image offers insight into the nature of response, each still supports the need for initial personal connections to the text whether the ultimate goal is motivating readers, enhancing reading ability, or creating…

  4. Algorithms evaluation for fundus images enhancement

    NASA Astrophysics Data System (ADS)

    Braem, V.; Marcos, M.; Bizai, G.; Drozdowicz, B.; Salvatelli, y. A.

    2011-12-01

    Color images of the retina inherently involve noise and illumination artifacts. In order to improve the diagnostic quality of the images, it is desirable to homogenize the non-uniform illumination and increase contrast while preserving color characteristics. The visual result of different pre-processing techniques can be very dissimilar and it is necessary to make an objective assessment of the techniques in order to select the most suitable. In this article the performance of eight algorithms to correct the non-uniform illumination, contrast modification and color preservation was evaluated. In order to choose the most suitable a general score was proposed. The results got good impression from experts, although some differences suggest that not necessarily the best statistical quality of image is the one of best diagnostic quality to the trained doctor eye. This means that the best pre-processing algorithm for an automatic classification may be different to the most suitable one for visual diagnosis. However, both should result in the same final diagnosis.

  5. Hyperspectral range imaging for transportation systems evaluation

    NASA Astrophysics Data System (ADS)

    Bridgelall, Raj; Rafert, J. B.; Atwood, Don; Tolliver, Denver D.

    2016-04-01

    Transportation agencies expend significant resources to inspect critical infrastructure such as roadways, railways, and pipelines. Regular inspections identify important defects and generate data to forecast maintenance needs. However, cost and practical limitations prevent the scaling of current inspection methods beyond relatively small portions of the network. Consequently, existing approaches fail to discover many high-risk defect formations. Remote sensing techniques offer the potential for more rapid and extensive non-destructive evaluations of the multimodal transportation infrastructure. However, optical occlusions and limitations in the spatial resolution of typical airborne and space-borne platforms limit their applicability. This research proposes hyperspectral image classification to isolate transportation infrastructure targets for high-resolution photogrammetric analysis. A plenoptic swarm of unmanned aircraft systems will capture images with centimeter-scale spatial resolution, large swaths, and polarization diversity. The light field solution will incorporate structure-from-motion techniques to reconstruct three-dimensional details of the isolated targets from sequences of two-dimensional images. A comparative analysis of existing low-power wireless communications standards suggests an application dependent tradeoff in selecting the best-suited link to coordinate swarming operations. This study further produced a taxonomy of specific roadway and railway defects, distress symptoms, and other anomalies that the proposed plenoptic swarm sensing system would identify and characterize to estimate risk levels.

  6. Evaluating Commercial Scanners for Astronomical Image Digitization

    NASA Astrophysics Data System (ADS)

    Simcoe, R. J.

    2009-08-01

    Many organizations have been interested in understanding if commercially available scanners are adequate for scientifically useful digitization. These scanners range in price from a few hundred to a few tens of thousands of dollars (USD), often with little apparent difference in performance specifications. This paper describes why the underlying technology used in flatbed scanners tends to effectively limit resolutions to the 600-1200 dots per inch (dpi) range and how the overall system Modulation Transfer Function (MTF) can be used to evaluate the quality of the digitized data for the small feature sizes found in astronomical images. Two scanners, the Epson V750 flatbed scanner and the Nikon Cool Scan 9000ED film strip scanner, are evaluated through their Modulation Transfer Functions (MTF). The MTF of the Harvard DASCH scanner is also shown for comparison. The particular goal of this evaluation was to understand if the scanners could be used for digitizing spectral plates at the University of Toronto. The plates of primary interest were about 15 mm (5/8 inch) wide by 180 mm (7~inches) long and ˜50 mm x 80 mm (2 x 3 inches). The results of the MTF work show that the Epson scanner, despite claims of high resolution, is of limited value for scientific imaging of feature sizes below about 50 μm and therefore not a good candidate for digitizing the spectral plates and problematic for scanning direct plates. The Nikon scanner is better and, except for some frustrating limitations in its software, its performance seems to hold promise as a digitizer for spectral plates in the University of Toronto collection.

  7. A protocol-based evaluation of medical image digitizers.

    PubMed

    Efstathopoulos, E P; Costaridou, L; Kocsis, O; Panayiotakis, G

    2001-09-01

    Medical film digitizers play an important transitory role as digital-to-analogue bridges in radiology. Their use requires performance evaluation to assure medical image quality. A complete quality control protocol is presented, based on a set of test objects adaptable to the specification of various digitizers. The protocol includes parameters such as uniformity, input-output response, noise, geometric distortion, spatial resolution, low contrast discrimination, film slippage and light leakage, as well as associated measurement methods. The applicability of the protocol is demonstrated with two types of medical film digitizers; a charge-coupled device (CCD) digitizer and a laser digitizer. The potential value of the protocol is also discussed. PMID:11560833

  8. Physiological imaging of electrical trauma and therapeutic responses

    NASA Astrophysics Data System (ADS)

    Chen, Chin-Tu; Matthews, K.; Aarsvold, John N.; Mintzer, Robert A.; Yasillo, Nicholas J.; Hannig, Jurgen; Capelli-Schellpfefer, M.; Cooper, Malcolm; Lee, Raphael C.

    2000-04-01

    In victims of electrical trauma, electroporation of cell membrane, in which lipid bilayer is permeabilized by thermal and electrical forces, is thought to be a substantial cause of tissue damage. It has been suggested that certain mild surfactant in low concentration could induce sealing of permeabilized lipid bilayers, thus repairing cell membranes that had not been extensively damaged. With an animal model of electrically injured hind limb of rats, we have demonstrated and validated the use of radiotracer imaging technique to assess the physiology of the damaged tissues after electrical shock and of their repairs after applying surfactant as a therapeutic strategy. For example, using Tc-99m labeled pyrophosphate (PYP), which follows calcium in cellular function and is known to accumulate in damaged tissues, we have established a physiological imaging approach for assessment of the extent of tissue injury for diagnosis and surgical planning, as well as for evaluation of responses to therapy. With the use of a small, hand-held, miniature gamma camera, this physiological imaging method can be employed at patient's bedside and even in the field, for example, at accident site or during transfer for emergency care, rapid diagnosis, and prompt treatment in order to maximize the chance for tissue survival.

  9. Fuzzy Index to Evaluate Edge Detection in Digital Images

    PubMed Central

    Perez-Ornelas, Felicitas; Mendoza, Olivia; Melin, Patricia; Castro, Juan R.; Rodriguez-Diaz, Antonio; Castillo, Oscar

    2015-01-01

    In literature, we can find different metrics to evaluate the detected edges in digital images, like Pratt's figure of merit (FOM), Jaccard’s index (JI) and Dice’s coefficient (DC). These metrics compare two images, the first one is the reference edges image, and the second one is the detected edges image. It is important to mention that all existing metrics must binarize images before their evaluation. Binarization step causes information to be lost because an incomplete image is being evaluated. In this paper, we propose a fuzzy index (FI) for edge evaluation that does not use a binarization step. In order to process all detected edges, images are represented in their fuzzy form and all calculations are made with fuzzy sets operators and fuzzy Euclidean distance between both images. Our proposed index is compared to the most used metrics using synthetic images, with good results. PMID:26115362

  10. Evaluation of automated emergency response systems

    SciTech Connect

    Addis, R.P.

    1988-12-31

    Automated Emergency Response (ER) systems are playing a greater role in providing prompt and reliable predictions of the impact of inadvertent releases of hazardous materials to the environment. Observed and forecast environmental and accident source term data are input into environmental transport and dispersion models to provide dosimetry estimates used as decision making aids for responding to emergencies. Several automated ER systems have been developed for US Federal Government facilities and many are available commercially. For such systems to be useful, they must reliably and consistently deliver a timely product to the decision makers. Evaluation of the entire ER system is essential to determine the performance that can be expected from the system during an emergency. Unfortunately, seldom are ER systems evaluated as a whole. Usually Quality Assurance programs evaluate the performance of individual components of the system. Most atmospheric pollution model evaluation methods usually involve an evaluation of the predictive performance of the transport and dispersion model when compared either with experimental tracer results or results from other models. Rarely, however, is the ability of the ER system to provide timely, reliable and consistent information evaluated. Such an evaluation is vital to determine the system performance during an emergency and to provide valuable information to aid in improving the system.

  11. Hemodynamic responses to functional activation accessed by optical imaging

    NASA Astrophysics Data System (ADS)

    Ni, Songlin; Li, Pengcheng; Yang, Yuanyuan; Lv, Xiaohua; Luo, Qingming

    2006-01-01

    A multi-wavelength light-emitting diode (LED) and laser diode (LD) based optical imaging system was developed to visualize the changes in cerebral blood flow, oxygenation following functional activation simultaneously in rodent cortex. The 2-D blood flow image was accessed by laser speckle contrast imaging, and the spectroscopic imaging of intrinsic signal was used for the calculation of oxyhemoglobin (HbO), deoxyhemoglobin (Hb) and total hemoglobin (HbT) concentration. The combination of spectroscopic imaging and laser speckle contrast imaging provides the capability to simultaneously investigate the spatial and temporal blood flow and hemoglobin concentration changes with high resolution, which may lead to a better understanding of the coupling between neuronal activation and vascular responses. The optical imaging system been built is compact and convenient to investigators. And it is reliable to acquire raw data. In present study, the hemodynamic responses to cortical spreading depression (CSD) in parietal cortex of ~-chloralose/urethan anesthetized rats were demonstrated.

  12. Overview and development about image scrambling degree evaluation

    NASA Astrophysics Data System (ADS)

    Wang, Congli; Chen, Zhi-Bin; Ding, Na-Na

    2014-11-01

    With the development of computer and network communication technology, researchers have advanced many image scrambling algorithms to resolve image information security. But how to evaluate the performance of these algorithms has not been studied scientifically. Most of the evaluation ways depend on the original image with large computing work. So it is an important problem to evaluate the image scrambling degree objectively. This paper summarizes the common evaluating parameters, describes their shortcomings and points out the directions about how to evaluate the scrambling degree scientifically further.

  13. Positron autoradiography for intravascular imaging: feasibility evaluation

    NASA Astrophysics Data System (ADS)

    Shikhaliev, Polad M.; Xu, Tong; Ducote, Justin L.; Easwaramoorthy, Balasubramaniam; Mukherjee, Jogeshwar; Molloi, Sabee

    2006-02-01

    Approximately 70% of acute coronary artery disease is caused by unstable (vulnerable) plaques with an inflammation of the overlying cap and high lipid content. A rupturing of the inflamed cap of the plaque results in propagation of the thrombus into the lumen, blockage of the artery and acute ischaemic syndrome or sudden death. Morphological imaging such as angiography or intravascular ultrasound cannot determine inflammation status of the plaque. A radiotracer such as 18F-FDG is accumulated in vulnerable plaques due to higher metabolic activity of the inflamed cap and could be used to detect a vulnerable plaque. However, positron emission tomography (PET) cannot detect the FDG-labelled plaques because of respiratory and heart motions, small size and low activity of the plaques. Plaques can be detected using a miniature particle (positron) detector inserted into the artery. In this work, a new detector concept is investigated for intravascular imaging of the plaques. The detector consists of a storage phosphor tip bound to the end of an intravascular catheter. It can be inserted into an artery, absorb the 18F-FDG positrons from the plaques, withdrawn from the artery and read out. Length and diameter of the storage phosphor tip can be matched to the length and the diameter of the artery. Monte Carlo simulations and experimental evaluations of coronary plaque imaging with the proposed detector were performed. It was shown that the sensitivity of the storage phosphor detector to the positrons of 18F-FDG is sufficient to detect coronary plaques with 1 mm and 2 mm sizes and 590 Bq and 1180 Bq activities in the arteries with 2 mm and 3 mm diameters, respectively. An experimental study was performed using plastic tubes with 2 mm diameter filled with an FDG solution, which simulates blood. FDG spots simulating plaques were placed over the surface of the tube. A phosphor tip was inserted into the tube and imaged the plaques. Exposure time was 1 min in all simulations and

  14. Effects of delta-9-tetrahydrocannabinol on evaluation of emotional images

    PubMed Central

    Ballard, Michael E; Bedi, Gillinder; de Wit, Harriet

    2013-01-01

    There is growing evidence that drugs of abuse alter processing of emotional information in ways that could be attractive to users. Our recent report that Δ9-tetrahydrocannabinol (THC) diminishes amygdalar activation in response to threat-related faces suggests that THC may modify evaluation of emotionally-salient, particularly negative or threatening, stimuli. In this study, we examined the effects of acute THC on evaluation of emotional images. Healthy volunteers received two doses of THC (7.5 and 15 mg; p.o.) and placebo across separate sessions before performing tasks assessing facial emotion recognition and emotional responses to pictures of emotional scenes. THC significantly impaired recognition of facial fear and anger, but it only marginally impaired recognition of sadness and happiness. The drug did not consistently affect ratings of emotional scenes. THC' effects on emotional evaluation were not clearly related to its mood-altering effects. These results support our previous work, and show that THC reduces perception of facial threat. Nevertheless, THC does not appear to positively bias evaluation of emotional stimuli in general PMID:22585232

  15. Evaluating glaucoma damage: emerging imaging technologies

    PubMed Central

    Kostanyan, Tigran; Wollstein, Gadi; Schuman, Joel S

    2015-01-01

    The use of ocular imaging tools to estimate structural and functional damage in glaucoma has become a common clinical practice and a substantial focus of vision research. The evolution of the imaging technologies through increased scanning speed, penetration depth, image registration and development of multimodal devices has the potential to detect the pathology more reliably and in earlier stages. This review is focused on new ocular imaging modalities used for glaucoma diagnosis. PMID:27087829

  16. Finger vein image quality evaluation using support vector machines

    NASA Astrophysics Data System (ADS)

    Yang, Lu; Yang, Gongping; Yin, Yilong; Xiao, Rongyang

    2013-02-01

    In an automatic finger-vein recognition system, finger-vein image quality is significant for segmentation, enhancement, and matching processes. In this paper, we propose a finger-vein image quality evaluation method using support vector machines (SVMs). We extract three features including the gradient, image contrast, and information capacity from the input image. An SVM model is built on the training images with annotated quality labels (i.e., high/low) and then applied to unseen images for quality evaluation. To resolve the class-imbalance problem in the training data, we perform oversampling for the minority class with random-synthetic minority oversampling technique. Cross-validation is also employed to verify the reliability and stability of the learned model. Our experimental results show the effectiveness of our method in evaluating the quality of finger-vein images, and by discarding low-quality images detected by our method, the overall finger-vein recognition performance is considerably improved.

  17. Evaluation of improvement of diffuse optical imaging of brain function by high-density probe arrangements and imaging algorithms

    NASA Astrophysics Data System (ADS)

    Sakakibara, Yusuke; Kurihara, Kazuki; Okada, Eiji

    2016-04-01

    Diffuse optical imaging has been applied to measure the localized hemodynamic responses to brain activation. One of the serious problems with diffuse optical imaging is the limitation of the spatial resolution caused by the sparse probe arrangement and broadened spatial sensitivity profile for each probe pair. High-density probe arrangements and an image reconstruction algorithm considering the broadening of the spatial sensitivity can improve the spatial resolution of the image. In this study, the diffuse optical imaging of the absorption change in the brain is simulated to evaluate the effect of the high-density probe arrangements and imaging methods. The localization error, equivalent full-width half maximum and circularity of the absorption change in the image obtained by the mapping and reconstruction methods from the data measured by five probe arrangements are compared to quantitatively evaluate the imaging methods and probe arrangements. The simple mapping method is sufficient for the density of the measurement points up to the double-density probe arrangement. The image reconstruction method considering the broadening of the spatial sensitivity of the probe pairs can effectively improve the spatial resolution of the image obtained from the probe arrangements higher than the quadruple density, in which the distance between the neighboring measurement points is 10.6 mm.

  18. Whole-mount imaging of responses in mouse vomeronasal neurons.

    PubMed

    Xu, Pei Sabrina; Holy, Timothy E

    2013-01-01

    Imaging permits the visualization of neural activity from the whole-mount vomeronasal sensory epithelium with single-cell resolution. The preparation preserves an intact tissue environment, enabling the robust detection of cellular responses upon chemical stimulation and study of the precise 3D mapping of vomeronasal sensory neuron (VSN) functional types within the epithelium. Using objective-coupled planar illumination (OCPI) microscopy to perform fast volumetric imaging, we routinely record the responses of thousands of VSNs for hours from a single intact vomeronasal organ preparation. Here we document the preparation of the whole-mounted vomeronasal epithelium, multichannel stimulus delivery, and three-dimensional calcium imaging by OCPI microscopy. PMID:24014363

  19. Test and analysis of spectral response for UV image intensifier

    NASA Astrophysics Data System (ADS)

    Qian, Yunsheng; Liu, Jian; Feng, Cheng; Lv, Yang; Zhang, Yijun

    2015-10-01

    The UV image intensifier is one kind of electric vacuum imaging device based on principle of photoelectronic imaging. To achieve solar-blind detection, its spectral response characteristic is extremely desirable. A broad spectrum response measurement system is developed. This instrument uses EQ-99 laser-driven light source to get broad spectrum in the range of 200 nm to 1700 nm. A special preamplifier as well as a test software is work out. The spectral response of the image intensifier can be tested in the range of 200~1700 nm. Using this spectrum response measuring instrument, the UV image intensifiers are tested. The spectral response at the spectral range of 200 nm to 600 nm are obtained. Because of the quantum efficiency of Te-Cs photocathode used in image intens ifier above 280nm wavelength still exists, especially at 280 nm to 320nm.Therefore, high-performance UV filters is required for solar blind UV detection. Based on two sets of UV filters, the influence of solar radiation on solar blind detection is calculated and analyzed.

  20. Image-Word Pairing-Congruity Effect on Affective Responses

    NASA Astrophysics Data System (ADS)

    Sanabria Z., Jorge C.; Cho, Youngil; Sambai, Ami; Yamanaka, Toshimasa

    The present study explores the effects of familiarity on affective responses (pleasure and arousal) to Japanese ad elements, based on the schema incongruity theory. Print ads showing natural scenes (landscapes) were used to create the stimuli (images and words). An empirical study was conducted to measure subjects' affective responses to image-word combinations that varied in terms of incongruity. The level of incongruity was based on familiarity levels, and was statistically determined by a variable called ‘pairing-congruity status’. The tested hypothesis proposed that even highly familiar image-word combinations, when combined incongruously, would elicit strong affective responses. Subjects assessed the stimuli using bipolar scales. The study was effective in tracing interactions between familiarity, pleasure and arousal, although the incongruous image-word combinations did not elicit the predicted strong effects on pleasure and arousal. The results suggest a need for further research incorporating kansei (i.e., creativity) into the process of stimuli selection.

  1. Treatment Response Evaluation and Follow-up in Hepatocellular Carcinoma

    PubMed Central

    Arora, Anil; Kumar, Ashish

    2014-01-01

    Hepatocellular carcinoma (HCC) is one of the major causes of morbidity, mortality and healthcare expenditure in patients with chronic liver disease. The management of HCC is evolving because of recently introduced novel therapeutic approaches. Optimal outcome requires an early and accurate assessment of tumor response to therapy. Current imaging modalities, such as computed tomography (CT) and magnetic resonance (MR) imaging; provide reliable and reproducible anatomical data in order to demonstrate tumor burden changes. However, in the setting of novel targeted therapies and liver directed treatments, simple tumor anatomical changes can be less informative and usually appear later than biological changes. There has been a growing interest to monitor the therapeutic response, at an early phase of treatment, by measuring tumor viability and/or perfusion. Therefore the importance of tumor viability assessment is increasingly being recognized. The tumor viability measurement guidelines have recently been amended to include the measurement of only the longest diameter of the enhancing tumors to formally amend RECIST to modified RECIST (mRECIST). Viable tumor should be defined as uptake of contrast agent in the arterial phase. In this review, we discuss criteria of response evaluation in HCC and further follow-up of patients receiving curative and palliative treatment. PMID:25755604

  2. EVALUATION OF COLOR ALTERATION ON FABRICS BY IMAGE ANALYSIS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evaluation of color changes is usually done manually and is often inconsistent. Image analysis provides a method in which to evaluate color-related testing that is not only simple, but also consistent. Image analysis can also be used to measure areas that were considered too large for the colorimet...

  3. Image quality evaluation and control of computer-generated holograms

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Hiroshi; Yamaguchi, Takeshi; Uetake, Hiroki

    2016-03-01

    Image quality of the computer-generated holograms are usually evaluated subjectively. For example, the re- constructed image from the hologram is compared with other holograms, or evaluated by the double-stimulus impairment scale method to compare with the original image. This paper proposes an objective image quality evaluation of a computer-generated hologram by evaluating both diffraction efficiency and peak signal-to-noise ratio. Theory and numerical experimental results are shown on Fourier transform transmission hologram of both amplitude and phase modulation. Results without the optimized random phase show that the amplitude transmission hologram gives better peak signal-to noise ratio, but the phase transmission hologram provides about 10 times higher diffraction efficiency to the amplitude type. As an optimized phase hologram, Kinoform is evaluated. In addition, we investigate to control image quality by non-linear operation.

  4. Elbow magnetic resonance imaging: imaging anatomy and evaluation.

    PubMed

    Hauptfleisch, Jennifer; English, Collette; Murphy, Darra

    2015-04-01

    The elbow is a complex joint. Magnetic resonance imaging (MRI) is often the imaging modality of choice in the workup of elbow pain, especially in sports injuries and younger patients who often have either a history of a chronic repetitive strain such as the throwing athlete or a distinct traumatic injury. Traumatic injuries and alternative musculoskeletal pathologies can affect the ligaments, musculotendinous, cartilaginous, and osseous structures of the elbow as well as the 3 main nerves to the upper limb, and these structures are best assessed with MRI.Knowledge of the complex anatomy of the elbow joint as well as patterns of injury and disease is important for the radiologist to make an accurate diagnosis in the setting of elbow pain. This chapter will outline elbow anatomy, basic imaging parameters, compartmental pathology, and finally applications of some novel MRI techniques. PMID:25835585

  5. Intrinsic optical signal imaging of glucose-stimulated physiological responses in the insulin secreting INS-1 β-cell line

    NASA Astrophysics Data System (ADS)

    Li, Yi-Chao; Cui, Wan-Xing; Wang, Xu-Jing; Amthor, Franklin; Yao, Xin-Cheng

    2011-03-01

    Intrinsic optical signal (IOS) imaging has been established for noninvasive monitoring of stimulus-evoked physiological responses in the retina and other neural tissues. Recently, we extended the IOS imaging technology for functional evaluation of insulin secreting INS-1 cells. INS-1 cells provide a popular model for investigating β-cell dysfunction and diabetes. Our experiments indicate that IOS imaging allows simultaneous monitoring of glucose-stimulated physiological responses in multiple cells with high spatial (sub-cellular) and temporal (sub-second) resolution. Rapid image sequences reveal transient optical responses that have time courses comparable to glucose-evoked β-cell electrical activities.

  6. Performance evaluation methodology for historical document image binarization.

    PubMed

    Ntirogiannis, Konstantinos; Gatos, Basilis; Pratikakis, Ioannis

    2013-02-01

    Document image binarization is of great importance in the document image analysis and recognition pipeline since it affects further stages of the recognition process. The evaluation of a binarization method aids in studying its algorithmic behavior, as well as verifying its effectiveness, by providing qualitative and quantitative indication of its performance. This paper addresses a pixel-based binarization evaluation methodology for historical handwritten/machine-printed document images. In the proposed evaluation scheme, the recall and precision evaluation measures are properly modified using a weighting scheme that diminishes any potential evaluation bias. Additional performance metrics of the proposed evaluation scheme consist of the percentage rates of broken and missed text, false alarms, background noise, character enlargement, and merging. Several experiments conducted in comparison with other pixel-based evaluation measures demonstrate the validity of the proposed evaluation scheme. PMID:23008259

  7. Spectral and fluorescence imaging of immune system and tissue response to an immunogenic agent

    NASA Astrophysics Data System (ADS)

    Choe, Se-woon; Acharya, Abhinav; Keselowsky, Benjamin G.; Sorg, Brian S.

    2009-05-01

    Imaging of immune system and tissue response to immunogenic agents can be important to the development of new biomaterials. Additionally, quantitative functional imaging can be useful for testing and evaluation of methods to alter or control the immune system response to implanted materials. In this preliminary study, we employ spectral imaging and fluorescence imaging to measure immune system and tissue response to implanted immunogenic agents. Poly (D,L lactide-co-glycolide) (PLGA) with a 50:50 composition was used to create immunogenic microparticles (MPs). Lipopolysaccharide (LPS) encapsulated in the MPs was used to provoke a tissue immune response in mice and encapsulated fluorescein isothiocyanate (FITC) was used to fluorescently label the MPs for imaging. Control MPs did not contain LPS. The MPs were delivered at 50 particles/μL in a total volume of 20μL by subcutaneous injection in the skin of a nude mouse in a dorsal skin-fold window chamber preparation. Cultured immune cells from a mouse leukemic monocyte macrophage cell line were exogenously labeled with the fluorescent dye DiD in solution at a concentration of 8000cells/μL. Immediately after window chamber surgery and implantation of the MPs, 100μL of the fluorescent macrophage solution was administered via the tail vein. Fluorescence imaging was used to track MPs and macrophages while spectral imaging was used for imaging and measurement of hemoglobin saturation in the tissue microvasculature. Imaging was performed periodically over about three days. The spectral and fluorescence imaging combination enabled detailed observations of the macrophage response and functional effects on the tissue.

  8. Monitoring human melanocytic cell responses to piperine using multispectral imaging

    NASA Astrophysics Data System (ADS)

    Samatham, Ravikant; Phillips, Kevin G.; Sonka, Julia; Yelma, Aznegashe; Reddy, Neha; Vanka, Meenakshi; Thuillier, Philippe; Soumyanath, Amala; Jacques, Steven

    2011-03-01

    Vitiligo is a depigmentary disease characterized by melanocyte loss attributed most commonly to autoimmune mechanisms. Currently vitiligo has a high incidence (1% worldwide) but a poor set of treatment options. Piperine, a compound found in black pepper, is a potential treatment for the depigmentary skin disease vitiligo, due to its ability to stimulate mouse epidermal melanocyte proliferation in vitro and in vivo. The present study investigates the use of multispectral imaging and an image processing technique based on local contrast to quantify the stimulatory effects of piperine on human melanocyte proliferation in reconstructed epidermis. We demonstrate the ability of the imaging method to quantify increased pigmentation in response to piperine treatment. The quantization of melanocyte stimulation by the proposed imaging technique illustrates the potential use of this technology to quickly assess therapeutic responses of vitiligo tissue culture models to treatment non-invasively.

  9. Satellite image collection modeling for large area hazard emergency response

    NASA Astrophysics Data System (ADS)

    Liu, Shufan; Hodgson, Michael E.

    2016-08-01

    Timely collection of critical hazard information is the key to intelligent and effective hazard emergency response decisions. Satellite remote sensing imagery provides an effective way to collect critical information. Natural hazards, however, often have large impact areas - larger than a single satellite scene. Additionally, the hazard impact area may be discontinuous, particularly in flooding or tornado hazard events. In this paper, a spatial optimization model is proposed to solve the large area satellite image acquisition planning problem in the context of hazard emergency response. In the model, a large hazard impact area is represented as multiple polygons and image collection priorities for different portion of impact area are addressed. The optimization problem is solved with an exact algorithm. Application results demonstrate that the proposed method can address the satellite image acquisition planning problem. A spatial decision support system supporting the optimization model was developed. Several examples of image acquisition problems are used to demonstrate the complexity of the problem and derive optimized solutions.

  10. Performance evaluation of infrared imaging system in field test

    NASA Astrophysics Data System (ADS)

    Wang, Chensheng; Guo, Xiaodong; Ren, Tingting; Zhang, Zhi-jie

    2014-11-01

    Infrared imaging system has been applied widely in both military and civilian fields. Since the infrared imager has various types and different parameters, for system manufacturers and customers, there is great demand for evaluating the performance of IR imaging systems with a standard tool or platform. Since the first generation IR imager was developed, the standard method to assess the performance has been the MRTD or related improved methods which are not perfect adaptable for current linear scanning imager or 2D staring imager based on FPA detector. For this problem, this paper describes an evaluation method based on the triangular orientation discrimination metric which is considered as the effective and emerging method to evaluate the synthesis performance of EO system. To realize the evaluation in field test, an experiment instrument is developed. And considering the importance of operational environment, the field test is carried in practical atmospheric environment. The test imagers include panoramic imaging system and staring imaging systems with different optics and detectors parameters (both cooled and uncooled). After showing the instrument and experiment setup, the experiment results are shown. The target range performance is analyzed and discussed. In data analysis part, the article gives the range prediction values obtained from TOD method, MRTD method and practical experiment, and shows the analysis and results discussion. The experimental results prove the effectiveness of this evaluation tool, and it can be taken as a platform to give the uniform performance prediction reference.

  11. Progress in Evaluating Quantitative Optical Gas Imaging

    EPA Science Inventory

    Development of advanced fugitive emission detection and assessment technologies that facilitate cost effective leak and malfunction mitigation strategies is an ongoing goal shared by industry, regulators, and environmental groups. Optical gas imaging (OGI) represents an importan...

  12. Evaluation of Dry Chemicals by Photoacoustic Imaging

    NASA Astrophysics Data System (ADS)

    Hoshimiya, Tsutomu

    1992-10-01

    In this study, an apparatus suitable to photoacoustic (PA) imaging to measure blood-analysis and urinalysis is fabricated and its measurement scheme has been established for the first time. The PA imaging of urinalysis test strip, blood sugar test strip, and cholesterol test strip is performed. A calibration curve of PA measurement is obtained for a urine test strip. The detectivity is better than that obtained by an eye-measurement.

  13. Evaluation of edge effect due to phase contrast imaging for mammography

    SciTech Connect

    Matsuo, Satoru; Katafuchi, Tetsuro; Tohyama, Keiko; Morishita, Junji; Yamada, Katsuhiko; Fujita, Hiroshi

    2005-08-15

    It is well-known that the edge effect produced by phase contrast imaging results in the edge enhancement of x-ray images and thereby sharpens those images. It has recently been reported that phase contrast imaging using practical x-ray tubes with small focal spots has improved image sharpness as observed in the phase contrast imaging with x-ray from synchrotron radiation or micro-focus x-ray tubes. In this study, we conducted the phase contrast imaging of a plastic fiber and plant seeds using a customized mammography equipment with a 0.1 mm focal spot, and the improvement of image sharpness was evaluated in terms of spatial frequency response of the images. We observed that the image contrast of the plastic fiber was increased by edge enhancement, and, as predicted elsewhere, spectral analysis revealed that as the spatial frequencies of the x-ray images increased, so did the sharpness gained through phase contrast imaging. Thus, phase contrast imaging using a practical molybdenum anode tube with a 0.1 mm-focal spot would benefit mammography, in which the morphological detectability of small species such as micro-calcifications is of great concern. And detectability of tumor-surrounded glandular tissues in dense breast would be also improved by the phase contrast imaging.

  14. Spectral analysis for evaluation of myocardial tracers for medical imaging

    SciTech Connect

    Huesman, Ronald H.; Reutter, Bryan W.; Marshall, Robert C.

    2000-10-11

    Kinetic analysis of dynamic tracer data is performed with the goal of evaluating myocardial radiotracers for cardiac nuclear medicine imaging. Data from experiments utilizing the isolated rabbit heart model are acquired by sampling the venous blood after introduction of a tracer of interest and a reference tracer. We have taken the approach that the kinetics are properly characterized by an impulse response function which describes the difference between the reference molecule (which does not leave the vasculature) and the molecule of interest which is transported across the capillary boundary and is made available to the cell. Using this formalism we can model the appearance of the tracer of interest in the venous output of the heart as a convolution of the appearance of the reference tracer with the impulse response. In this work we parameterize the impulse response function as the sum of a large number of exponential functions whose predetermined decay constants form a spectrum, and each is required only to have a nonnegative coefficient. This approach, called spectral analysis, has the advantage that it allows conventional compartmental analysis without prior knowledge of the number of compartments which the physiology may require or which the data will support.

  15. Lower-Dark-Current, Higher-Blue-Response CMOS Imagers

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata; Cunningham, Thomas; Hancock, Bruce

    2008-01-01

    Several improved designs for complementary metal oxide/semiconductor (CMOS) integrated-circuit image detectors have been developed, primarily to reduce dark currents (leakage currents) and secondarily to increase responses to blue light and increase signal-handling capacities, relative to those of prior CMOS imagers. The main conclusion that can be drawn from a study of the causes of dark currents in prior CMOS imagers is that dark currents could be reduced by relocating p/n junctions away from Si/SiO2 interfaces. In addition to reflecting this conclusion, the improved designs include several other features to counteract dark-current mechanisms and enhance performance.

  16. Evaluation of a cloud-based local-read paradigm for imaging evaluations in oncology clinical trials for lung cancer

    PubMed Central

    Kobayashi, Naomi; Bonnard, Eric; Charbonnier, Colette; Yamamichi, Junta; Mizobe, Hideaki; Kimura, Shinya

    2015-01-01

    Background Although tumor response evaluated with radiological imaging is frequently used as a primary endpoint in clinical trials, it is difficult to obtain precise results because of inter- and intra-observer differences. Purpose To evaluate usefulness of a cloud-based local-read paradigm implementing software solutions that standardize imaging evaluations among international investigator sites for clinical trials of lung cancer. Material and Methods Two studies were performed: KUMO I and KUMO I Extension. KUMO I was a pilot study aiming at demonstrating the feasibility of cloud implementation and identifying issues regarding variability of evaluations among sites. Chest CT scans at three time-points from baseline to progression, from 10 patients with lung cancer who were treated with EGFR tyrosine kinase inhibitors, were evaluated independently by two oncologists (Japan) and one radiologist (France), through a cloud-based software solution. The KUMO I Extension was performed based on the results of KUMO I. Results KUMO I showed discordance rates of 40% for target lesion selection, 70% for overall response at the first time-point, and 60% for overall response at the second time-point. Since the main reason for the discordance was differences in the selection of target lesions, KUMO I Extension added a cloud-based quality control service to achieve a consensus on the selection of target lesions, resulting in an improved rate of agreement of response evaluations. Conclusion The study shows the feasibility of imaging evaluations at investigator sites, based on cloud services for clinical studies involving multiple international sites. This system offers a step forward in standardizing evaluations of images among widely dispersed sites. PMID:26668754

  17. Earth Observing-1 Advanced Land Imager: Radiometric Response Calibration

    NASA Technical Reports Server (NTRS)

    Mendenhall, J. A.; Lencioni, D. E.; Evans, J. B.

    2000-01-01

    The Advanced Land Imager (ALI) is one of three instruments to be flown on the first Earth Observing mission (EO-1) under NASA's New Millennium Program (NMP). ALI contains a number of innovative features, including a wide field of view optical design, compact multispectral focal plane arrays, non-cryogenic HgCdTe detectors for the short wave infrared bands, and silicon carbide optics. This document outlines the techniques adopted during ground calibration of the radiometric response of the Advanced Land Imager. Results from system level measurements of the instrument response, signal-to-noise ratio, saturation radiance, and dynamic range for all detectors of every spectral band are also presented.

  18. PIRATE: pediatric imaging response assessment and targeting environment

    NASA Astrophysics Data System (ADS)

    Glenn, Russell; Zhang, Yong; Krasin, Matthew; Hua, Chiaho

    2010-02-01

    By combining the strengths of various imaging modalities, the multimodality imaging approach has potential to improve tumor staging, delineation of tumor boundaries, chemo-radiotherapy regime design, and treatment response assessment in cancer management. To address the urgent needs for efficient tools to analyze large-scale clinical trial data, we have developed an integrated multimodality, functional and anatomical imaging analysis software package for target definition and therapy response assessment in pediatric radiotherapy (RT) patients. Our software provides quantitative tools for automated image segmentation, region-of-interest (ROI) histogram analysis, spatial volume-of-interest (VOI) analysis, and voxel-wise correlation across modalities. To demonstrate the clinical applicability of this software, histogram analyses were performed on baseline and follow-up 18F-fluorodeoxyglucose (18F-FDG) PET images of nine patients with rhabdomyosarcoma enrolled in an institutional clinical trial at St. Jude Children's Research Hospital. In addition, we combined 18F-FDG PET, dynamic-contrast-enhanced (DCE) MR, and anatomical MR data to visualize the heterogeneity in tumor pathophysiology with the ultimate goal of adaptive targeting of regions with high tumor burden. Our software is able to simultaneously analyze multimodality images across multiple time points, which could greatly speed up the analysis of large-scale clinical trial data and validation of potential imaging biomarkers.

  19. Quantitative image quality evaluation for cardiac CT reconstructions

    NASA Astrophysics Data System (ADS)

    Tseng, Hsin-Wu; Fan, Jiahua; Kupinski, Matthew A.; Balhorn, William; Okerlund, Darin R.

    2016-03-01

    Maintaining image quality in the presence of motion is always desirable and challenging in clinical Cardiac CT imaging. Different image-reconstruction algorithms are available on current commercial CT systems that attempt to achieve this goal. It is widely accepted that image-quality assessment should be task-based and involve specific tasks, observers, and associated figures of merits. In this work, we developed an observer model that performed the task of estimating the percentage of plaque in a vessel from CT images. We compared task performance of Cardiac CT image data reconstructed using a conventional FBP reconstruction algorithm and the SnapShot Freeze (SSF) algorithm, each at default and optimal reconstruction cardiac phases. The purpose of this work is to design an approach for quantitative image-quality evaluation of temporal resolution for Cardiac CT systems. To simulate heart motion, a moving coronary type phantom synchronized with an ECG signal was used. Three different percentage plaques embedded in a 3 mm vessel phantom were imaged multiple times under motion free, 60 bpm, and 80 bpm heart rates. Static (motion free) images of this phantom were taken as reference images for image template generation. Independent ROIs from the 60 bpm and 80 bpm images were generated by vessel tracking. The observer performed estimation tasks using these ROIs. Ensemble mean square error (EMSE) was used as the figure of merit. Results suggest that the quality of SSF images is superior to the quality of FBP images in higher heart-rate scans.

  20. Geometric and Radiometric Evaluation of Rasat Images

    NASA Astrophysics Data System (ADS)

    Cam, Ali; Topan, Hüseyin; Oruç, Murat; Özendi, Mustafa; Bayık, Çağlar

    2016-06-01

    RASAT, the second remote sensing satellite of Turkey, was designed and assembled, and also is being operated by TÜBİTAK Uzay (Space) Technologies Research Institute (Ankara). RASAT images in various levels are available free-of-charge via Gezgin portal for Turkish citizens. In this paper, the images in panchromatic (7.5 m GSD) and RGB (15 m GSD) bands in various levels were investigated with respect to its geometric and radiometric characteristics. The first geometric analysis is the estimation of the effective GSD as less than 1 pixel for radiometrically processed level (L1R) of both panchromatic and RGB images. Secondly, 2D georeferencing accuracy is estimated by various non-physical transformation models (similarity, 2D affine, polynomial, affine projection, projective, DLT and GCP based RFM) reaching sub-pixel accuracy using minimum 39 and maximum 52 GCPs. The radiometric characteristics are also investigated for 8 bits, estimating SNR between 21.8-42.2, and noise 0.0-3.5 for panchromatic and MS images for L1R when the sea is masked to obtain the results for land areas. The analysis show that RASAT images satisfies requirements for various applications. The research is carried out in Zonguldak test site which is mountainous and partly covered by dense forest and urban areas.

  1. Image Registration for Quantitative Parametric Response Mapping of Cancer Treatment Response1

    PubMed Central

    Boes, Jennifer L; Hoff, Benjamin A; Hylton, Nola; Pickles, Martin D; Turnbull, Lindsay W; Schott, Anne F; Rehemtulla, Alnawaz; Chamberlain, Ryan; Lemasson, Benjamin; Chenevert, Thomas L; Galbán, Craig J; Meyer, Charles R; Ross, Brian D

    2014-01-01

    Imaging biomarkers capable of early quantification of tumor response to therapy would provide an opportunity to individualize patient care. Image registration of longitudinal scans provides a method of detecting treatment associated changes within heterogeneous tumors by monitoring alterations in the quantitative value of individual voxels over time, which is unattainable by traditional volumetric-based histogram methods. The concepts involved in the use of image registration for tracking and quantifying breast cancer treatment response using parametric response mapping (PRM), a voxel-based analysis of diffusion-weighted magnetic resonance imaging (DW-MRI) scans, are presented. Application of PRM to breast tumor response detection is described, wherein robust registration solutions for tracking small changes in water diffusivity in breast tumors during therapy are required. Methodologies that employ simulations are presented for measuring expected statistical accuracy of PRM for response assessment. Test-retest clinical scans are used to yield estimates of system noise to indicate significant changes in voxel-based changes in water diffusivity. Overall, registration-based PRM image analysis provides significant opportunities for voxel-based image analysis to provide the required accuracy for early assessment of response to treatment in breast cancer patients receiving neoadjuvant chemotherapy. PMID:24772213

  2. Quantitative evaluation of image registration techniques in the case of retinal images

    NASA Astrophysics Data System (ADS)

    Gavet, Yann; Fernandes, Mathieu; Pinoli, Jean-Charles

    2012-04-01

    In human retina observation (with non mydriatic optical microscopes), an image registration process is often employed to enlarge the field of view. Analyzing all the images takes a lot of time. Numerous techniques have been proposed to perform the registration process. Its good evaluation is a difficult question that is then raising. This article presents the use of two quantitative criterions to evaluate and compare some classical feature-based image registration techniques. The images are first segmented and the resulting binary images are then registered. The good quality of the registration process is evaluated with a normalized criterion based on the ɛ dissimilarity criterion, and the figure of merit criterion (fom), for 25 pairs of images with a manual selection of control points. These criterions are normalized by the results of the affine method (considered as the most simple method). Then, for each pair, the influence of the number of points used to perform the registration is evaluated.

  3. Reflected light imaging of ON and OFF responses in frog retina

    NASA Astrophysics Data System (ADS)

    Yao, Xin-Cheng; Liu, Lei; Li, Yang-Guo

    2009-02-01

    Using a near infrared (NIR) light flood-illumination imager equipped with a high-speed CCD camera, we demonstrated reflected light imaging of stimulus-evoked retinal ON and OFF responses in isolated, but intact, frog eye. Both fast and slow transient intrinsic optical signals (IOSs) were observed. Fast optical response occurred immediately after the stimulus onset, and correlated tightly with the ON and OFF edges of the visible light stimulus. High resolution images revealed both positive (increasing) and negative (decreasing) IOSs, and dynamic optical change at individual CCD pixels could often exceed 10% of the background light intensity. Our experiment on isolated eye suggests that further development of fast, high resolution fundus imager will allow robust detection of fast IOSs in vivo, and thus allow noninvasive, three-dimensional evaluation of retinal neural function.

  4. Millimeter-wave imaging sensor data evaluation

    NASA Technical Reports Server (NTRS)

    Wilson, William J.; Ibbott, Anthony C.

    1987-01-01

    A passive 3-mm radiometer system with a mechanically scanned antenna was built for use on a small aircraft or an Unmanned Aerial Vehicle to produce real near-real-time, moderate-resolution (0.5) images of the ground. One of the main advantages of this passive imaging sensor is that it is able to provide surveillance information through dust, smoke, fog and clouds when visual and IR systems are unusable. It can also be used for a variety of remote sensing applications, such as measurements of surface moisture, surface temperature, vegetation extent and snow cover. It is also possible to detect reflective objects under vegetation cover.

  5. Evaluation of response after pre-operative radiotherapy in soft tissue sarcomas; the European Organisation for Research and Treatment of Cancer-Soft Tissue and Bone Sarcoma Group (EORTC-STBSG) and Imaging Group recommendations for radiological examination and reporting with an emphasis on magnetic resonance imaging.

    PubMed

    Messiou, C; Bonvalot, S; Gronchi, A; Vanel, D; Meyer, M; Robinson, P; Morosi, C; Bloem, J L; Terrier, P H; Lazar, A; Le Péchoux, C; Wardelman, E; Winfield, J M; Boulet, B; Bovée, J; Haas, R L

    2016-03-01

    At present, there is no standardised approach for the radiological evaluation of soft tissue sarcomas following radiotherapy (RT). This manuscript, produced by a European Organisation for Research and Treatment of Cancer-Soft Tissue and Bone Sarcoma Group (EORTC-STBSG) and Imaging Group endorsed task force, aims to propose standardisation of magnetic resonance imaging techniques and interpretation after neoadjuvant RT for routine use and within clinical trials. PMID:26802529

  6. Advanced imaging techniques in the therapeutic response of transarterial chemoembolization for hepatocellular carcinoma.

    PubMed

    Yang, Ke; Zhang, Xiao-Ming; Yang, Lin; Xu, Hao; Peng, Juan

    2016-05-28

    Hepatocellular carcinoma (HCC) is one of the major causes of morbidity and mortality in patients with chronic liver disease. Transarterial chemoembolization (TACE) can significantly improve the survival rate of patients with HCC and is the first treatment choice for patients who are not suitable for surgical resections. The evaluation of the response to TACE treatment affects not only the assessment of the therapy efficacy but also the development of the next step in the treatment plan. The use of imaging to examine changes in tumor volume to assess the response of solid tumors to treatment has been controversial. In recent years, the emergence of new imaging technology has made it possible to observe the response of tumors to treatment prior to any morphological changes. In this article, the advances in studies reporting the use of computed tomography perfusion imaging, diffusion-weighted magnetic resonance imaging (MRI), intravoxel incoherent motion, diffusion kurtosis imaging, magnetic resonance spectroscopy, magnetic resonance perfusion-weighted imaging, blood oxygen level-dependent MRI, positron emission tomography (PET)/computed tomography and PET/MRI to assess the TACE treatment response are reviewed. PMID:27239110

  7. Advanced imaging techniques in the therapeutic response of transarterial chemoembolization for hepatocellular carcinoma

    PubMed Central

    Yang, Ke; Zhang, Xiao-Ming; Yang, Lin; Xu, Hao; Peng, Juan

    2016-01-01

    Hepatocellular carcinoma (HCC) is one of the major causes of morbidity and mortality in patients with chronic liver disease. Transarterial chemoembolization (TACE) can significantly improve the survival rate of patients with HCC and is the first treatment choice for patients who are not suitable for surgical resections. The evaluation of the response to TACE treatment affects not only the assessment of the therapy efficacy but also the development of the next step in the treatment plan. The use of imaging to examine changes in tumor volume to assess the response of solid tumors to treatment has been controversial. In recent years, the emergence of new imaging technology has made it possible to observe the response of tumors to treatment prior to any morphological changes. In this article, the advances in studies reporting the use of computed tomography perfusion imaging, diffusion-weighted magnetic resonance imaging (MRI), intravoxel incoherent motion, diffusion kurtosis imaging, magnetic resonance spectroscopy, magnetic resonance perfusion-weighted imaging, blood oxygen level-dependent MRI, positron emission tomography (PET)/computed tomography and PET/MRI to assess the TACE treatment response are reviewed. PMID:27239110

  8. Quality evaluation of fruit by hyperspectral imaging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter presents new applications of hyperspectral imaging for measuring the optical properties of fruits and assessing their quality attributes. A brief overview is given of current techniques for measuring optical properties of turbid and opaque biological materials. Then a detailed descripti...

  9. Veni, vidi, vici: in vivo molecular imaging of immune response.

    PubMed

    Gross, Shimon; Moss, Britney L; Piwnica-Worms, David

    2007-10-01

    "I came, I saw, I conquered," Julius Caesar proclaimed, highlighting the importance of direct visualization as a winning strategy. Continuing the "From the Field" series (see Editorial [2007] 26, 131), Gross et al. summarize how modern molecular imaging techniques can successfully dissect the complexities of immune response in vivo. PMID:17967405

  10. Student Image, Student Evaluation and Education.

    ERIC Educational Resources Information Center

    Tate, Eugene D.

    In this paper the author investigates the function of student evaluation in relation to the educational process. He concludes that traditional approaches are inadequate because they view evaluation as either a static measure of information comprehension or as a coercive tool. The author, instead of viewing education as static, linear…

  11. Longitudinal, multimodal functional imaging of microvascular response to photothermal therapy

    PubMed Central

    Bui, Albert K.; Teves, Kathleen M.; Indrawan, Elmer; Jia, Wangcun; Choi, Bernard

    2012-01-01

    Although studies have shown that photothermal therapy can coagulate selectively abnormal vasculature, the ability of this method to achieve consistent, complete removal of the vasculature is questionable. We present the use of multimodal, wide-field functional imaging to study, in greater detail, the biological response to selective laser injury. Specifically, a single-platform instrument capable of coregistered fluorescence imaging and laser speckle imaging was utilized to monitor vascular endothelial growth factor gene expression and blood flow, respectively, in a transgenic rodent model. Collectively, the longitudinal, in vivo data collected with our instrument suggest that the biological response to selective laser injury involves early-stage redistribution of blood flow, followed by increased vascular endothelial growth factor promoter activity to stimulate pro-angiogenic events. PMID:20890338

  12. Stress induced hypertensive response: should it be evaluated more carefully?

    PubMed Central

    2011-01-01

    Various diagnostic methods have been used to evaluate hypertensive patients under physical and pharmacological stress. Several studies have shown that exercise hypertension has an independent, adverse impact on outcome; however, other prognostic studies have shown that exercise hypertension is a favorable prognostic indicator and associated with good outcome. Exercise hypertension may be encountered as a warning signal of hypertension at rest and future hypertensive left ventricular hypertrophy. The results of diagnostic stress tests support that hypertensive response to exercise is frequently associated with high rate-pressure product in hypertensives. In addition to the observations on high rate-pressure product and enhanced ventricular contractility in patients with hypertension, evaluation of myocardial contractility by Doppler tissue imaging has shown hyperdynamic myocardial function under pharmacological stress. These recent quantitative data in hypertensives suggest that hyperdynamic myocardial function and high rate-pressure product response to stress may be related to exaggerated hypertension, which may have more importance than that it has been already given in clinical practice. PMID:21846346

  13. An Evaluation of the Construct of Body Image.

    ERIC Educational Resources Information Center

    Banfield, Sophie S.; McCabe, Marita P.

    2002-01-01

    Evaluates the efficacy of a multidimensional model of body image that incorporated the dimensions of perception, affect, cognition, and behavior. Results did not support the hypothesized four-factor model, but rather a model that consisted of three factors. The results highlight the multidimensionality of the body image construct and the…

  14. Using short-wave infrared imaging for fruit quality evaluation

    NASA Astrophysics Data System (ADS)

    Zhang, Dong; Lee, Dah-Jye; Desai, Alok

    2013-12-01

    Quality evaluation of agricultural and food products is important for processing, inventory control, and marketing. Fruit size and surface quality are two important quality factors for high-quality fruit such as Medjool dates. Fruit size is usually measured by length that can be done easily by simple image processing techniques. Surface quality evaluation on the other hand requires more complicated design, both in image acquisition and image processing. Skin delamination is considered a major factor that affects fruit quality and its value. This paper presents an efficient histogram analysis and image processing technique that is designed specifically for real-time surface quality evaluation of Medjool dates. This approach, based on short-wave infrared imaging, provides excellent image contrast between the fruit surface and delaminated skin, which allows significant simplification of image processing algorithm and reduction of computational power requirements. The proposed quality grading method requires very simple training procedure to obtain a gray scale image histogram for each quality level. Using histogram comparison, each date is assigned to one of the four quality levels and an optimal threshold is calculated for segmenting skin delamination areas from the fruit surface. The percentage of the fruit surface that has skin delamination can then be calculated for quality evaluation. This method has been implemented and used for commercial production and proven to be efficient and accurate.

  15. Diagnostic imaging in the evaluation of vascular birthmarks.

    PubMed

    Burrows, P E; Laor, T; Paltiel, H; Robertson, R L

    1998-07-01

    This article reviews the role of modern diagnostic imaging in the evaluation of patients with vascular birthmarks. There are two main categories of vascular anomalies: hemangiomas and vascular malformations. The findings on plain radiography, sonography, computed tomography (CT), magnetic resonance imaging (MRI) and angiography, and the appropriate sequence of investigation for the different vascular anomalies are discussed. PMID:9704205

  16. Imaging Evaluation of Dogs and Cats with Dysphagia

    PubMed Central

    Pollard, Rachel E.

    2012-01-01

    The current literature is reviewed in this paper regarding the application of diagnostic imaging in the evaluation of swallowing disorders of the dog. The applications of radiography, contrast radiography, and contrast videofluoroscopy are discussed with pertinent case examples provided for emphasis. The indications for image-guided interventions are also described. PMID:23762579

  17. Quantification of Kr-81m ventilation image response to methacholine

    SciTech Connect

    Byrom, E.; Chausow, A.; Ryo, U.Y.; Kim, I.; Pinsky, S.

    1984-01-01

    Ventilation imaging with Kr-81m was used to study the response of regional ventilation to bronchial provocation with methacholine. Subjects were imaged seated, for 2 min, following inhalation of methacoline. Then maximal flow at 30% of vital capacity (MEF-30p) and forced expiratory volume in 1 sec (FEV 1) were measured. The procedure was repeated for 11 doses. Total ventilation is constant by design. Regional changes between each image (T) and a baseline image (B) were measured from a difference image (D), where D/sub i/=(S.T/sub i/-B/sub i/)/sqrt (S/sup 2/.T/sub i/+B/sub i/), and S normalizes T to the same total counts as B. The D/sub i/ values have a gaussian distribution with standard deviation (SD)=1, if B, T are independent images of the same object. The area of mismatch (AOM) between the D/sub i/ histogram and the ideal qaussian curve, and its SD, were calculated. Thresholds of significant response were established at 2.0 for SD, 1100 for AOM to allow for the effects of repositioning. Three subjects undertook the provocation study. In subject number 1(2,3), MEF-30p fell below 70% of baseline after dose number 8(7,6); a region of reduced ventilation was seen in D, at the left lung base, after dose 6(4,5); SD rose above the threshold after dose 7(6,7); AOM after dose 8(6,7). In subjects 2 and 3, FEV 1 fell below 80% of baseline after dose 10. In conclusion SD, AOM are as sensitive as MEF-30p in detecting response to methacholine: and more sensitive than FEV 1. The D images may be more sensitive, if repositioning artifacts can be avoided.

  18. Image Information Mining System Evaluation Using Information-Theoretic Measures

    NASA Astrophysics Data System (ADS)

    Daschiel, Herbert; Datcu, Mihai

    2005-12-01

    During the last decade, the exponential increase of multimedia and remote sensing image archives, the fast expansion of the world wide web, and the high diversity of users have yielded concepts and systems for successful content-based image retrieval and image information mining. Image data information systems require both database and visual capabilities, but there is a gap between these systems. Database systems usually do not deal with multidimensional pictorial structures and vision systems do not provide database query functions. In terms of these points, the evaluation of content-based image retrieval systems became a focus of research interest. One can find several system evaluation approaches in literature, however, only few of them go beyond precision-recall graphs and do not allow a detailed evaluation of an interactive image retrieval system. Apart from the existing evaluation methodologies, we aim at the overall validation of our knowledge-driven content-based image information mining system. In this paper, an evaluation approach is demonstrated that is based on information-theoretic quantities to determine the information flow between system levels of different semantic abstraction and to analyze human-computer interactions.

  19. 2D magnetic nanoparticle imaging using magnetization response second harmonic

    NASA Astrophysics Data System (ADS)

    Tanaka, Saburo; Murata, Hayaki; Oishi, Tomoya; Suzuki, Toshifumi; Zhang, Yi

    2015-06-01

    A detection method and an imaging technique for magnetic nanoparticles (MNPs) have been investigated. In MNP detection and in magnetic particle imaging (MPI), the most commonly employed method is the detection of the odd harmonics of the magnetization response. We examined the advantage of using the second harmonic response when applying an AC magnetic modulation field and a DC bias field. If the magnetization response is detected by a Cu-wound-coil detection system, the output voltage from the coil is proportional to the change in the flux, dϕ/dt. Thus, the dependence of the derivative of the magnetization, M, on an AC magnetic modulation field and a DC bias field were calculated and investigated. The calculations were in good agreement with the experimental results. We demonstrated that the use of the second harmonic response for the detection of MNPs has an advantage compared with the usage of the third harmonic response, when the Cu-wound-coil detection system is employed and the amplitude of the ratio of the AC modulation field and a knee field Hac/Hk is less than 2. We also constructed a 2D MPI scanner using a pair of permanent ring magnets with a bore of ϕ80 mm separated by 90 mm. The magnets generated a gradient of Gz=3.17 T/m transverse to the imaging bore and Gx=1.33 T/m along the longitudinal axis. An original concentrated 10 μl Resovist solution in a ϕ2×3 mm2 vessel was used as a sample, and it was imaged by the scanner. As a result, a 2D contour map image could be successfully generated using the method with a lock-in amplifier.

  20. Bone metastases: assessment of therapeutic response through radiological and nuclear medicine imaging modalities.

    PubMed

    Vassiliou, V; Andreopoulos, D; Frangos, S; Tselis, N; Giannopoulou, E; Lutz, S

    2011-11-01

    Radiological and nuclear medicine imaging modalities used for assessing bone metastases treatment response include plain and digitalised radiography (XR), skeletal scintigraphy (SS), dual-energy X-ray absorptiometry (DEXA), computed tomography (CT), magnetic resonance imaging (MRI), [(18)F] fluorodeoxyglucose positron emission tomography (FDG-PET) and PET/CT. Here we discuss the advantages and disadvantages of these assessment modalities as evident through different clinical trials. Additionally, we present the more established response criteria of the International Union Against Cancer and the World Health Organization and compare them with newer MD Anderson criteria. Even though serial XR and SS have been used to assess the therapeutic response for decades, several months are required before changes are evident. Newer techniques, such as MRI or PET, may allow an earlier evaluation of response that may be quantified through monitoring changes in signal intensity and standard uptake value, respectively. Moreover, the application of PET/CT, which can follow both morphological and metabolic changes, has yielded interesting and promising results that give a new insight into the natural history of metastatic bone disease. However, only a few studies have investigated the application of these newer techniques and further clinical trials are needed to corroborate their promising results and establish the most suitable imaging parameters and evaluation time points. Last, but not least, there is an absolute need to adopt uniform response criteria for bone metastases through an international consensus in order to better assess treatment response in terms of accuracy and objectivity. PMID:21530193

  1. Brain responses strongly correlate with Weibull image statistics when processing natural images.

    PubMed

    Scholte, H Steven; Ghebreab, Sennay; Waldorp, Lourens; Smeulders, Arnold W M; Lamme, Victor A F

    2009-01-01

    The visual appearance of natural scenes is governed by a surprisingly simple hidden structure. The distributions of contrast values in natural images generally follow a Weibull distribution, with beta and gamma as free parameters. Beta and gamma seem to structure the space of natural images in an ecologically meaningful way, in particular with respect to the fragmentation and texture similarity within an image. Since it is often assumed that the brain exploits structural regularities in natural image statistics to efficiently encode and analyze visual input, we here ask ourselves whether the brain approximates the beta and gamma values underlying the contrast distributions of natural images. We present a model that shows that beta and gamma can be easily estimated from the outputs of X-cells and Y-cells. In addition, we covaried the EEG responses of subjects viewing natural images with the beta and gamma values of those images. We show that beta and gamma explain up to 71% of the variance of the early ERP signal, substantially outperforming other tested contrast measurements. This suggests that the brain is strongly tuned to the image's beta and gamma values, potentially providing the visual system with an efficient way to rapidly classify incoming images on the basis of omnipresent low-level natural image statistics. PMID:19757938

  2. Functional evaluation of telemedicine with super high definition images and B-ISDN.

    PubMed

    Takeda, H; Matsumura, Y; Okada, T; Kuwata, S; Komori, M; Takahashi, T; Minatom, K; Hashimoto, T; Wada, M; Fujio, Y

    1998-01-01

    In order to determine whether a super high definition (SHD) image running at a series of 2048 resolution x 2048 line x 60 frame/sec was capable of telemedicine, we established a filing system for medical images and two experiments for transmission of high quality images were performed. All images of various types, produced from one case of ischemic heart disease were digitized and registered into the filing system. Images consisted of plain chest x-ray, electrocardiogram, ultrasound cardiogram, cardiac scintigram, coronary angiogram, left ventriculogram and so on. All images were animated and totaled a number of 243. We prepared a graphic user interface (GUI) for image retrieval based on the medical events and modalities. Twenty one cardiac specialists evaluated quality of the SHD images to be somewhat poor compared to the original pictures but sufficient for making diagnoses, and effective as a tool for teaching and case study purposes. The system capability of simultaneously displaying several animated images was especially deemed effective in grasping comprehension of diagnosis. Efficient input methods and creating capacity of filing all produced images are future issue. Using B-ISDN network, the SHD file was prefetched to the servers at Kyoto University Hospital and BBCC (Bradband ISDN Business chance & Culture Creation) laboratory as an telemedicine experiment. Simultaneous video conference system, the control of image retrieval and pointing function made the teleconference successful in terms of high quality of medical images, quick response time and interactive data exchange. PMID:10384469

  3. A Molecular Imaging Paradigm to Rapidly Profile Response to Angiogenesis-directed Therapy in Small Animals

    PubMed Central

    Virostko, John; Xie, Jingping; Hallahan, Dennis E.; Arteaga, Carlos L.; Gore, John C.; Manning, H. Charles

    2009-01-01

    Purpose The development of novel angiogenesis-directed therapeutics is hampered by the lack of non-invasive imaging metrics capable of assessing treatment response. We report the development and validation of a novel molecular imaging paradigm to rapidly assess response to angiogenesis-directed therapeutics in preclinical animal models. Procedures A monoclonal antibody-based optical imaging probe targeting vascular endothelial growth factor receptor-2 (VEGFR2) expression was synthesized and evaluated in vitro and in vivo via multispectral fluorescence imaging. Results The optical imaging agent demonstrated specificity for the target receptor in cultured endothelial cells and in vivo. The agent exhibited significant accumulation within 4T1 xenograft tumors. Mice bearing 4T1 xenografts and treated with sunitinib exhibited both tumor growth arrest and decreased accumulation of NIR800-αVEGFR2ab compared to untreated cohorts (p=0.0021). Conclusions Molecular imaging of VEGFR2 expression is a promising non-invasive biomarker for assessing angiogenesis and evaluating the efficacy of angiogenesis-directed therapies. PMID:19130143

  4. Molecular Magnetic Resonance Imaging of Tumor Response to Therapy

    PubMed Central

    Shuhendler, Adam J.; Ye, Deju; Brewer, Kimberly D.; Bazalova-Carter, Magdalena; Lee, Kyung-Hyun; Kempen, Paul; Dane Wittrup, K.; Graves, Edward E.; Rutt, Brian; Rao, Jianghong

    2015-01-01

    Personalized cancer medicine requires measurement of therapeutic efficacy as early as possible, which is optimally achieved by three-dimensional imaging given the heterogeneity of cancer. Magnetic resonance imaging (MRI) can obtain images of both anatomy and cellular responses, if acquired with a molecular imaging contrast agent. The poor sensitivity of MRI has limited the development of activatable molecular MR contrast agents. To overcome this limitation of molecular MRI, a novel implementation of our caspase-3-sensitive nanoaggregation MRI (C-SNAM) contrast agent is reported. C-SNAM is triggered to self-assemble into nanoparticles in apoptotic tumor cells, and effectively amplifies molecular level changes through nanoaggregation, enhancing tissue retention and spin-lattice relaxivity. At one-tenth the current clinical dose of contrast agent, and following a single imaging session, C-SNAM MRI accurately measured the response of tumors to either metronomic chemotherapy or radiation therapy, where the degree of signal enhancement is prognostic of long-term therapeutic efficacy. Importantly, C-SNAM is inert to immune activation, permitting radiation therapy monitoring. PMID:26440059

  5. Feature Evaluation for Building Facade Images - AN Empirical Study

    NASA Astrophysics Data System (ADS)

    Yang, M. Y.; Förstner, W.; Chai, D.

    2012-08-01

    The classification of building facade images is a challenging problem that receives a great deal of attention in the photogrammetry community. Image classification is critically dependent on the features. In this paper, we perform an empirical feature evaluation task for building facade images. Feature sets we choose are basic features, color features, histogram features, Peucker features, texture features, and SIFT features. We present an approach for region-wise labeling using an efficient randomized decision forest classifier and local features. We conduct our experiments with building facade image classification on the eTRIMS dataset, where our focus is the object classes building, car, door, pavement, road, sky, vegetation, and window.

  6. Non-uniform system response detection for hyperspectral imaging systems

    NASA Astrophysics Data System (ADS)

    Castorena, Juan; Morrison, Jason; Paliwal, Jitendra; Erkinbaev, Chyngyz

    2015-11-01

    Near infrared (NIR) hyperspectral imaging (HSI) has established itself as a powerful non-destructive tool for the chemical analysis of heterogeneous samples. However, one of the main disadvantages of NIR HSI is that the technique suffers from instrumentation-related problems, which in turn affect the acquired images. In general, focal plane array (FPA) based hyperspectral systems are affected by spatial and spectral non-uniform response, the presence of defective sensors (e.g. dead or saturated sensors), and temporal and spatial (e.g. dark current) noise. Another issue is each new camera system needs to be calibrated to assess its specific responses to light. To correct for these issues, we used known standards to measure the response of the sensors and capture the location of the field of view and defective sensors using linear and quadratic models. The parameters of these models were then used as input features for classification of sensor responses using a k-means algorithm. The results conclude that linear models are insufficiently precise for calibration but estimate sufficiently accurately the system's response and functionality. Specifically, it was shown that the classification method discriminates non-responsive regions effectively.

  7. An empirical evaluation of exemplar based image inpainting algorithms for natural scene image completion

    NASA Astrophysics Data System (ADS)

    Sangeetha, K.; Sengottuvelan, P.

    2013-03-01

    Image inpainting is the process of filling in of missing region so as to preserve its overall continuity. Image inpainting is manipulation and modification of an image in a form that is not easily detected. Digital image inpainting is relatively new area of research, but numerous and different approaches to tackle the inpainting problem have been proposed since the concept was first introduced. This paper analyzes and compares two recent exemplar based inpainting algorithms by Zhaolin Lu et al and Hao Guo et al. A number of examples on real images are demonstrated to evaluate the results of algorithms using Peak Signal to Noise Ratio (PSNR).

  8. Mastering moral misery: Emotional and coping responses to intragroup morality (vs. competence) evaluations.

    PubMed

    van der Lee, Romy; Ellemers, Naomi; Scheepers, Daan

    2016-01-01

    In social groups, individuals are often confronted with evaluations of their behaviour by other group members and are motivated to adapt their own behaviour accordingly. In two studies we examine emotional responses towards, and perceived coping abilities with, morality vs. competence evaluations individuals receive from other in-group members. In Study 1, we show that evaluations of one's immoral behaviour primarily induce guilt, whereas evaluations of incompetent behaviour raise anger. In Study 2, we elaborate on the psychological process associated with these emotional responses, and demonstrate that evaluations of immorality, compared to incompetence, diminish group members' perceived coping abilities, which in turn intensifies feelings of guilt. However, when anticipating an opportunity to restore one's self-image as a moral group member, perceived coping abilities are increased and the experience of guilt is alleviated. Together these studies demonstrate how group members can overcome their moral misery when restoring their self-image. PMID:26192008

  9. Evaluation of a hyperspectral image database for demosaicking purposes

    NASA Astrophysics Data System (ADS)

    Larabi, Mohamed-Chaker; Süsstrunk, Sabine

    2011-01-01

    We present a study on the the applicability of hyperspectral images to evaluate color filter array (CFA) design and the performance of demosaicking algorithms. The aim is to simulate a typical digital still camera processing pipe-line and to compare two different scenarios: evaluate the performance of demosaicking algorithms applied to raw camera RGB values before color rendering to sRGB, and evaluate the performance of demosaicking algorithms applied on the final sRGB color rendered image. The second scenario is the most frequently used one in literature because CFA design and algorithms are usually tested on a set of existing images that are already rendered, such as the Kodak Photo CD set containing the well-known lighthouse image. We simulate the camera processing pipe-line with measured spectral sensitivity functions of a real camera. Modeling a Bayer CFA, we select three linear demosaicking techniques in order to perform the tests. The evaluation is done using CMSE, CPSNR, s-CIELAB and MSSIM metrics to compare demosaicking results. We find that the performance, and especially the difference between demosaicking algorithms, is indeed significant depending if the mosaicking/demosaicking is applied to camera raw values as opposed to already rendered sRGB images. We argue that evaluating the former gives a better indication how a CFA/demosaicking combination will work in practice, and that it is in the interest of the community to create a hyperspectral image dataset dedicated to that effect.

  10. Evaluation of ventricular function with gated cardiac magnetic resonance imaging.

    PubMed

    Osbakken, M; Yuschok, T

    1986-01-01

    To determine the feasibility of using planar images obtained with gated cardiac magnetic resonance imaging (MRI) techniques to evaluate ventricular contractile function, cardiac chamber volume (V), and ejection fraction (EF) were calculated using MR images obtained in five previously catheterized patients. Patients were imaged with a .15-Tesla 55-cm bore magnet using the ECG to gate the images. Spin echo pulse sequences (30/500, TE/TR) were used to produce images in the transverse (T), coronal (C), and sagittal (S) planes at end diastole (ED) and end systole (ES). Slice thickness was 1.5 cm, with 2-mm resolution. A calibration grid was imaged in each plane to determine correction factors. Cardiac chamber areas were determined via planimetry. An area-length-volume algorithm was used to obtain EDV and ESV. Three combinations of biplane images in ES and ED were used (T/C, T/S, C/S). Volume data were used to calculate EF. Contrast ventriculogram volumes tended to be greater than MRI volumes, but EFs were similar with both techniques. In conclusion, gated cardiac MR images can be used to evaluate the ventricular function parameters of volume and ejection fraction. PMID:3731263

  11. Magnetic resonance imaging of the chest in the evaluation of cancer patients: state of the art

    PubMed Central

    Guimaraes, Marcos Duarte; Hochhegger, Bruno; Santos, Marcel Koenigkam; Santana, Pablo Rydz Pinheiro; Sousa, Arthur Soares; Souza, Luciana Soares; Marchiori, Edson

    2015-01-01

    Magnetic resonance imaging (MRI) has several advantages in the evaluation of cancer patients with thoracic lesions, including involvement of the chest wall, pleura, lungs, mediastinum, esophagus and heart. It is a quite useful tool in the diagnosis, staging, surgical planning, treatment response evaluation and follow-up of these patients. In the present review, the authors contextualize the relevance of MRI in the evaluation of thoracic lesions in cancer patients. Considering that MRI is a widely available method with high contrast and spatial resolution and without the risks associated with the use of ionizing radiation, its use combined with new techniques such as cine-MRI and functional methods such as perfusion- and diffusion-weighted imaging may be useful as an alternative tool with performance comparable or complementary to conventional radiological methods such as radiography, computed tomography and PET/CT imaging in the evaluation of patients with thoracic neoplasias. PMID:25798006

  12. Methods for the analysis of ordinal response data in medical image quality assessment.

    PubMed

    Keeble, Claire; Baxter, Paul D; Gislason-Lee, Amber J; Treadgold, Laura A; Davies, Andrew G

    2016-07-01

    The assessment of image quality in medical imaging often requires observers to rate images for some metric or detectability task. These subjective results are used in optimization, radiation dose reduction or system comparison studies and may be compared to objective measures from a computer vision algorithm performing the same task. One popular scoring approach is to use a Likert scale, then assign consecutive numbers to the categories. The mean of these response values is then taken and used for comparison with the objective or second subjective response. Agreement is often assessed using correlation coefficients. We highlight a number of weaknesses in this common approach, including inappropriate analyses of ordinal data and the inability to properly account for correlations caused by repeated images or observers. We suggest alternative data collection and analysis techniques such as amendments to the scale and multilevel proportional odds models. We detail the suitability of each approach depending upon the data structure and demonstrate each method using a medical imaging example. Whilst others have raised some of these issues, we evaluated the entire study from data collection to analysis, suggested sources for software and further reading, and provided a checklist plus flowchart for use with any ordinal data. We hope that raised awareness of the limitations of the current approaches will encourage greater method consideration and the utilization of a more appropriate analysis. More accurate comparisons between measures in medical imaging will lead to a more robust contribution to the imaging literature and ultimately improved patient care. PMID:26975497

  13. Imaging evaluation of patients with osteonecrosis of the femoral head.

    PubMed

    Pierce, Todd P; Jauregui, Julio J; Cherian, Jeffrey J; Elmallah, Randa K; Mont, Michael A

    2015-09-01

    Imaging modalities for the diagnosis of osteonecrosis (ON) of the femoral head have been studied extensively, but there have been few reports strictly addressing radiographic evaluation. The purpose of this report is to examine the use and role of (1) plain radiographs, (2) magnetic resonance imaging (MRI), (3) computerized tomography (CT), (4) bone scanning, and (5) positron emission topography (PET) for the diagnostic evaluation of ON. Plain radiographs are a mainstay in diagnosis but have very low sensitivity for early ON. MRI is the gold standard for diagnostic evaluation but may not identify subchondral fractures on collapse as well as CT scan or tomogram. Bone scanning should not be used for diagnosis due to its low sensitivity. PET scanning does not have a definitive role in diagnosis yet. Future research should focus on the role of new imaging technologies in evaluation. PMID:26045084

  14. Politics in evaluation: Politically responsive evaluation in high stakes environments.

    PubMed

    Azzam, Tarek; Levine, Bret

    2015-12-01

    The role of politics has often been discussed in evaluation theory and practice. The political influence of the situation can have major effects on the evaluation design, approach and methods. Politics also has the potential to influence the decisions made from the evaluation findings. The current study focuses on the influence of the political context on stakeholder decision making. Utilizing a simulation scenario, this study compares stakeholder decision making in high and low stakes evaluation contexts. Findings suggest that high stakes political environments are more likely than low stakes environments to lead to reduced reliance on technically appropriate measures and increased dependence on measures better reflect the broader political environment. PMID:26283476

  15. Imaging and acetylcholinesterase inhibitor response in dementia with Lewy bodies.

    PubMed

    Graff-Radford, Jonathan; Boeve, Bradley F; Pedraza, Otto; Ferman, Tanis J; Przybelski, Scott; Lesnick, Timothy G; Vemuri, Prashanthi; Senjem, Matthew L; Smith, Glenn E; Knopman, David S; Lowe, Val; Jack, Clifford R; Petersen, Ronald C; Kantarci, Kejal

    2012-08-01

    Acetylcholinesterase inhibitors are commonly used to treat patients with dementia with Lewy bodies. Hippocampal atrophy on magnetic resonance imaging and amyloid-β load on positron emission tomography are associated with the Alzheimer's disease-related pathology in patients with dementia with Lewy bodies. To date, few studies have investigated imaging markers that predict treatment response in patients with dementia with Lewy bodies. Our objective was to determine whether imaging markers of Alzheimer's disease-related pathology such as hippocampal volume, brain amyloid-β load on (11)C Pittsburgh compound B positron emission tomography predict treatment response to acetylcholinesterase inhibitors in patients with dementia with Lewy bodies. We performed a retrospective analysis on consecutive treatment-naive patients with dementia with Lewy bodies (n = 54) from the Mayo Clinic Alzheimer's Disease Research Centre who subsequently received acetylcholinesterase inhibitors and underwent magnetic resonance imaging with hippocampal volumetry. Baseline and follow-up assessments were obtained with the Mattis Dementia Rating Scale. Subjects were divided into three groups (reliable improvement, stable or reliable decline) using Dementia Rating Scale reliable change indices determined previously. Associations between hippocampal volumes and treatment response were tested with analysis of covariance adjusting for baseline Dementia Rating Scale, age, gender, magnetic resonance field strength and Dementia Rating Scale interval. Seven subjects underwent (11)C Pittsburgh compound B imaging within 12 weeks of magnetic resonance imaging. Global cortical (11)C Pittsburgh compound B retention (scaled to cerebellar retention) was calculated in these patients. Using a conservative psychometric method of assessing treatment response, there were 12 patients with reliable decline, 29 stable cases and 13 patients with reliable improvement. The improvers had significantly larger

  16. Evaluation of outliers in acquired brain MR images

    NASA Astrophysics Data System (ADS)

    Moldovanu, S.; (Vişan Pungǎ, M.; Moraru, L.

    2015-01-01

    Pre-processing is an important stage in the analysis of magnetic resonance images (MRI), because the effect of specific image artefacts, such as intensity inhomogeneity, noise and low contrast can adversely affect the quantitative image analysis. The image histogram is a useful tool in the analysis of MR images given that it allows a close relationship with important image features such as contrast and noise. The noise and variable contrast are elements that locally modify the quality of images. The key issue of this study derives from the fact that the spatial histogram can contain outliers indicating corrupted image information through the disorder of the bins. These aberrant errors should be excluded from the studied data sets. Here, the outliers are evaluated by using rigorous methods based on the probability theory and Chauvenet (CC), Grubbs (GC) and Peirce's (PC) criteria. In order to check the quality of the MR images, the Minkowsky (MD), Euclidean (ED) and cosine (CD) distance functions were used. They act as similarity scores between the histogram of the acquired MRI and the processed image. This analysis is necessary because, sometimes, the distance function exceeds the co-domain because of the outliers. In this paper, 32 MRIs are tested and the outliers are removed so that the distance functions generate uncorrupted and real values.

  17. Adaptive optics and phase diversity imaging for responsive space applications.

    SciTech Connect

    Smith, Mark William; Wick, David Victor

    2004-11-01

    The combination of phase diversity and adaptive optics offers great flexibility. Phase diverse images can be used to diagnose aberrations and then provide feedback control to the optics to correct the aberrations. Alternatively, phase diversity can be used to partially compensate for aberrations during post-detection image processing. The adaptive optic can produce simple defocus or more complex types of phase diversity. This report presents an analysis, based on numerical simulations, of the efficiency of different modes of phase diversity with respect to compensating for specific aberrations during post-processing. It also comments on the efficiency of post-processing versus direct aberration correction. The construction of a bench top optical system that uses a membrane mirror as an active optic is described. The results of characterization tests performed on the bench top optical system are presented. The work described in this report was conducted to explore the use of adaptive optics and phase diversity imaging for responsive space applications.

  18. Accommodation response measurements for integral 3D image

    NASA Astrophysics Data System (ADS)

    Hiura, H.; Mishina, T.; Arai, J.; Iwadate, Y.

    2014-03-01

    We measured accommodation responses under integral photography (IP), binocular stereoscopic, and real object display conditions, and viewing conditions of binocular and monocular viewing conditions. The equipment we used was an optometric device and a 3D display. We developed the 3D display for IP and binocular stereoscopic images that comprises a high-resolution liquid crystal display (LCD) and a high-density lens array. The LCD has a resolution of 468 dpi and a diagonal size of 4.8 inches. The high-density lens array comprises 106 x 69 micro lenses that have a focal length of 3 mm and diameter of 1 mm. The lenses are arranged in a honeycomb pattern. The 3D display was positioned 60 cm from an observer under IP and binocular stereoscopic display conditions. The target was presented at eight depth positions relative to the 3D display: 15, 10, and 5 cm in front of the 3D display, on the 3D display panel, and 5, 10, 15 and 30 cm behind the 3D display under the IP and binocular stereoscopic display conditions. Under the real object display condition, the target was displayed on the 3D display panel, and the 3D display was placed at the eight positions. The results suggest that the IP image induced more natural accommodation responses compared to the binocular stereoscopic image. The accommodation responses of the IP image were weaker than those of a real object; however, they showed a similar tendency with those of the real object under the two viewing conditions. Therefore, IP can induce accommodation to the depth positions of 3D images.

  19. Response Style Contamination of Student Evaluation Data

    ERIC Educational Resources Information Center

    Dolnicar, Sara; Grun, Bettina

    2009-01-01

    Student evaluation surveys provide instructors with feedback regarding development opportunities and they form the basis of promotion and tenure decisions. Student evaluations have been extensively studied, but one dimension hitherto neglected is the actual measurement aspect: which questions to ask, how to ask them, and what answer options to…

  20. Metabolic PET Imaging in Cancer Detection and Therapy Response

    PubMed Central

    Zhu, Aizhi; Lee, Daniel; Shim, Hyunsuk

    2010-01-01

    Positron emission tomography (PET) is a noninvasive imaging technique that provides a functional or metabolic assessment of normal tissue or disease conditions. 18F-fluorodeoxyglucose PET imaging (FDG-PET) is widely used clinically for tumor imaging due to increased glucose metabolism in most types of tumors, and has been shown to improve the diagnosis and subsequent treatment of cancers. In this chapter, we review its use in cancer diagnosis, staging, restaging, and assessment of response to treatment. In addition, other metabolic PET imaging agents in research or clinical trial stages are discussed, including amino acid analogs based on increased protein synthesis, and choline, which is based on increased membrane lipid synthesis. Amino acid analogs and choline are more specific to tumor cells than FDG, so they play an important role in differentiating cancers from benign conditions and in the diagnosis of cancers with low FDG uptake or high background FDG uptake. For decades, researchers have shown that tumors have altered metabolic profiles and display elevated uptake of glucose, amino acids, and lipids, which can be used for cancer diagnosis and monitoring of the therapeutic response with excellent signal-to-noise ratios. PMID:21362516

  1. [An improved medical image fusion algorithm and quality evaluation].

    PubMed

    Chen, Meiling; Tao, Ling; Qian, Zhiyu

    2009-08-01

    Medical image fusion is of very important value for application in medical image analysis and diagnosis. In this paper, the conventional method of wavelet fusion is improved,so a new algorithm of medical image fusion is presented and the high frequency and low frequency coefficients are studied respectively. When high frequency coefficients are chosen, the regional edge intensities of each sub-image are calculated to realize adaptive fusion. The choice of low frequency coefficient is based on the edges of images, so that the fused image preserves all useful information and appears more distinctly. We apply the conventional and the improved fusion algorithms based on wavelet transform to fuse two images of human body and also evaluate the fusion results through a quality evaluation method. Experimental results show that this algorithm can effectively retain the details of information on original images and enhance their edge and texture features. This new algorithm is better than the conventional fusion algorithm based on wavelet transform. PMID:19813594

  2. Computer-aided breast MR image feature analysis for prediction of tumor response to chemotherapy

    SciTech Connect

    Aghaei, Faranak; Tan, Maxine; Liu, Hong; Zheng, Bin; Hollingsworth, Alan B.; Qian, Wei

    2015-11-15

    Purpose: To identify a new clinical marker based on quantitative kinetic image features analysis and assess its feasibility to predict tumor response to neoadjuvant chemotherapy. Methods: The authors assembled a dataset involving breast MR images acquired from 68 cancer patients before undergoing neoadjuvant chemotherapy. Among them, 25 patients had complete response (CR) and 43 had partial and nonresponse (NR) to chemotherapy based on the response evaluation criteria in solid tumors. The authors developed a computer-aided detection scheme to segment breast areas and tumors depicted on the breast MR images and computed a total of 39 kinetic image features from both tumor and background parenchymal enhancement regions. The authors then applied and tested two approaches to classify between CR and NR cases. The first one analyzed each individual feature and applied a simple feature fusion method that combines classification results from multiple features. The second approach tested an attribute selected classifier that integrates an artificial neural network (ANN) with a wrapper subset evaluator, which was optimized using a leave-one-case-out validation method. Results: In the pool of 39 features, 10 yielded relatively higher classification performance with the areas under receiver operating characteristic curves (AUCs) ranging from 0.61 to 0.78 to classify between CR and NR cases. Using a feature fusion method, the maximum AUC = 0.85 ± 0.05. Using the ANN-based classifier, AUC value significantly increased to 0.96 ± 0.03 (p < 0.01). Conclusions: This study demonstrated that quantitative analysis of kinetic image features computed from breast MR images acquired prechemotherapy has potential to generate a useful clinical marker in predicting tumor response to chemotherapy.

  3. Evaluation of automated target detection using image fusion

    NASA Astrophysics Data System (ADS)

    Irvine, John M.; Abramson, Susan; Mossing, John

    2003-09-01

    Reliance on Automated Target Recognition (ATR) technology is essential to the future success of Intelligence, Surveillance, and Reconnaissance (ISR) missions. Although benefits may be realized through ATR processing of a single data source, fusion of information across multiple images and multiple sensors promises significant performance gains. A major challenge, as ATR fusion technologies mature, is the establishment of sound methods for evaluating ATR performance in the context of data fusion. The Deputy Under Secretary of Defense for Science and Technology (DUSD/S&T), as part of their ongoing ATR Program, has sponsored an effort to develop and demonstrate methods for evaluating ATR algorithms that utilize multiple data source, i.e., fusion-based ATR. This paper presents results from this program, focusing on the target detection and cueing aspect of the problem. The first step in assessing target detection performance is to relate the ground truth to the ATR decisions. Once the ATR decisions have been mapped to ground truth, the second step in the evaluation is to characterize ATR performance. A common approach is to vary the confidence threshold of the ATR and compute the Probability of Detection (PD) and the False Alarm Rate (FAR) associated with each threshold. Varying the threshold, therefore, produces an empirical performance curve relating detection performance to false alarms. Various statistical methods have been developed, largely in the medical imaging literature, to model this curve so that statistical inferences are possible. One approach, based on signal detection theory, generalizes the Receiver Operator Characteristic (ROC) curve. Under this approach, the Free Response Operating Characteristic (FROC) curve models performance for search problems. The FROC model is appropriate when multiple detections are possible and the number of false alarms is unconstrained. The parameterization of the FROC model provides a natural method for characterizing both

  4. Quantitative SPECT brain imaging: Effects of attenuation and detector response

    SciTech Connect

    Gilland, D.R.; Jaszczak, R.J.; Bowsher, J.E.; Turkington, T.G.; Liang, Z.; Greer, K.L.; Coleman, R.E. . Dept. of Radiology)

    1993-06-01

    Two physical factors that substantially degrade quantitative accuracy in SPECT imaging of the brain are attenuation and detector response. In addition to the physical factors, random noise in the reconstructed image can greatly affect the quantitative measurement. The purpose of this work was to implement two reconstruction methods that compensate for attenuation and detector response, a 3D maximum likelihood-EM method (ML) and a filtered backprojection method (FB) with Metz filter and Chang attenuation compensation, and compare the methods in terms of quantitative accuracy and image noise. The methods were tested on simulated data of the 3D Hoffman brain phantom. The simulation incorporated attenuation and distance-dependent detector response. Bias and standard deviation of reconstructed voxel intensities were measured in the gray and white matter regions. The results with ML showed that in both the gray and white matter regions as the number of iterations increased, bias decreased and standard deviation increased. Similar results were observed with FB as the Metz filter power increased. In both regions, ML had smaller standard deviation than FB for a given bias. Reconstruction times for the ML method have been greatly reduced through efficient coding, limited source support, and by computing attenuation factors only along rays perpendicular to the detector.

  5. Crowdsourcing-based evaluation of privacy in HDR images

    NASA Astrophysics Data System (ADS)

    Korshunov, Pavel; Nemoto, Hiromi; Skodras, Athanassios; Ebrahimi, Touradj

    2014-05-01

    The ability of High Dynamic Range imaging (HDRi) to capture details in high-contrast environments, making both dark and bright regions clearly visible, has a strong implication on privacy. However, the extent to which HDRi affects privacy when it is used instead of typical Standard Dynamic Range imaging (SDRi) is not yet clear. In this paper, we investigate the effect of HDRi on privacy via crowdsourcing evaluation using the Microworkers platform. Due to the lack of HDRi standard privacy evaluation dataset, we have created such dataset containing people of varying gender, race, and age, shot indoor and outdoor and under large range of lighting conditions. We evaluate the tone-mapped versions of these images, obtained by several representative tone-mapping algorithms, using subjective privacy evaluation methodology. Evaluation was performed using crowdsourcing-based framework, because it is a popular and effective alternative to traditional lab-based assessment. The results of the experiments demonstrate a significant loss of privacy when even tone-mapped versions of HDR images are used compared to typical SDR images shot with a standard exposure.

  6. Metal artifact reduction and image quality evaluation of lumbar spine CT images using metal sinogram segmentation.

    PubMed

    Kaewlek, Titipong; Koolpiruck, Diew; Thongvigitmanee, Saowapak; Mongkolsuk, Manus; Thammakittiphan, Sastrawut; Tritrakarn, Siri-on; Chiewvit, Pipat

    2015-01-01

    Metal artifacts often appear in the images of computed tomography (CT) imaging. In the case of lumbar spine CT images, artifacts disturb the images of critical organs. These artifacts can affect the diagnosis, treatment, and follow up care of the patient. One approach to metal artifact reduction is the sinogram completion method. A mixed-variable thresholding (MixVT) technique to identify the suitable metal sinogram is proposed. This technique consists of four steps: 1) identify the metal objects in the image by using k-mean clustering with the soft cluster assignment, 2) transform the image by separating it into two sinograms, one of which is the sinogram of the metal object, with the surrounding tissue shown in the second sinogram. The boundary of the metal sinogram is then found by the MixVT technique, 3) estimate the new value of the missing data in the metal sinogram by linear interpolation from the surrounding tissue sinogram, 4) reconstruct a modified sinogram by using filtered back-projection and complete the image by adding back the image of the metal object into the reconstructed image to form the complete image. The quantitative and clinical image quality evaluation of our proposed technique demonstrated a significant improvement in image clarity and detail, which enhances the effectiveness of diagnosis and treatment. PMID:26756404

  7. Metastatic renal cell carcinoma imaging evaluation in the era of anti-angiogenic therapies.

    PubMed

    Sirous, Reza; Henegan, John C; Zhang, Xu; Howard, Candace M; Souza, Frederico; Smith, Andrew D

    2016-06-01

    During the last decade, the arsenal of anti-angiogenic (AAG) agents used to treat metastatic renal cell carcinoma (RCC) has grown and revolutionized the treatment of metastatic RCC, leading to improved overall survival compared to conventional chemotherapy and traditional immunotherapy agents. AAG agents include inhibitors of vascular endothelial growth factor receptor signaling pathways and mammalian target of rapamycin inhibitors. Both of these classes of targeted agents are considered cytostatic rather than cytotoxic, inducing tumor stabilization rather than marked tumor shrinkage. As a result, decreases in tumor size alone are often minimal and/or occur late in the course of successful AAG therapy, while tumor devascularization is a distinct feature of AAG therapy. In successful AAG therapy, tumor devascularization manifests on computed tomography images as a composite of a decrease in tumor size, a decrease in tumor attenuation, and the development of tumor necrosis. In this article, we review Response Evaluation Criteria in Solid Tumors (RECIST)-the current standard of care for tumor treatment response assessment which is based merely on changes in tumor length-and its assessment of metastatic RCC tumor response in the era of AAG therapies. We then review the features of an ideal tumor imaging biomarker for predicting metastatic RCC response to a particular AAG agent and serving as a longitudinal tumor response assessment tool. Finally, a discussion of the more recently proposed imaging response criteria and new imaging trends in metastatic RCC response assessment will be reviewed. PMID:27193601

  8. [Evaluation of imaging biomarker by transgenic mouse models].

    PubMed

    Maeda, Jun; Higuchi, Makoto; Suhara, Tetsuya

    2009-04-01

    The invention of trangenic and gene knockout mice contributes to the understanding of various brain functions. With the previous-generation positron emission tomography (PET) camera it was impossible to visualize the mouse brain functions, while the newly developed small-animal PET camera with higher resolution is enough to visualize the mouse brain functions. In the present study, we investigated the visualization of functional brain images for a few transgenic mouse models using the small-animal PET. In neurodegenerative illnesses such as Alzheimer disease (AD), the relationship between etiopathology and main symptoms has been elucidated relatively well; therefore several transgenic mice have been already developed. We succeeded in visualizing amyloid images in human mutant amyloid precursor protein (APP) transgenic mice brains. This result suggested that small-animal PET enabled the quantitative analysis of pathologies in the Tg mouse brain. Psychiatric disorders are presumed to have underlying multiple neural dysfunctions. Despite some efficient medicinal therapies having been already established, the etiopathology of mental illness and its biological markers have not been clarified. Thus, we investigated in type II Ca-calmodulin-dependent protein kinase alpha (CaMKII alpha) heterozygous knockout (hKO) mouse, a major protein kinase in the brain. The CaMKII alpha hKO mice have several abnormal behavioral phenotypes, such as hyper aggression and lack of anxiogenic responses; therefore CaMKII alpha might involve in the pathogenesis of mood disorder and affect personal characterizations. Furthermore, serotonin (5-HT) 1A receptor density in the CaMKII alpha hKO mouse brain changed among various brain regions compared to wild mice. These mechanistic insights, PET assays of Tg mice that we have established here, provide an efficient methodology for preclinical evaluation of emerging diagnostic and therapeutic agents for neurodegenerative and psychiatric illnesses

  9. Predictive imaging of chemotherapeutic response in a transgenic mouse model of pancreatic cancer.

    PubMed

    Wang, Ping; Yoo, Byunghee; Sherman, Sarah; Mukherjee, Pinku; Ross, Alana; Pantazopoulos, Pamela; Petkova, Victoria; Farrar, Christian; Medarova, Zdravka; Moore, Anna

    2016-08-01

    The underglycosylated mucin 1 tumor antigen (uMUC1) is a biomarker that forecasts the progression of adenocarcinomas. In this study, we evaluated the utility of a dual-modality molecular imaging approach based on targeting uMUC1 for monitoring chemotherapeutic response in a transgenic murine model of pancreatic cancer (KCM triple transgenic mice). An uMUC1-specific contrast agent (MN-EPPT) was synthesized for use with magnetic resonance imaging (MRI) and fluorescence optical imaging. It consisted of dextran-coated iron oxide nanoparticles conjugated to the near infrared fluorescent dye Cy5.5 and to a uMUC1-specific peptide (EPPT). KCM triple transgenic mice were given gemcitabine as chemotherapy while control animals received saline injections following the same schedule. Changes in uMUC1 levels following chemotherapy were monitored using T2-weighted MRI and optical imaging before and 24 hr after injection of the MN-EPPT. uMUC1 expression in tumors from both groups was evaluated by histology and qRT-PCR. We observed that the average delta-T2 in the gemcitabine-treated group was significantly reduced compared to the control group indicating lower accumulation of MN-EPPT, and correspondingly, a lower level of uMUC1 expression. In vivo optical imaging confirmed the MRI findings. Fluorescence microscopy of pancreatic tumor sections showed a lower level of uMUC1 expression in the gemcitabine-treated group compared to the control, which was confirmed by qRT-PCR. Our data proved that changes in uMUC1 expression after gemcitabine chemotherapy could be evaluated using MN-EPPT-enhanced in vivo MR and optical imaging. These results suggest that the uMUC1-targeted imaging approach could provide a useful tool for the predictive assessment of therapeutic response. PMID:26996122

  10. On-Line IDCMS Evaluation of Different Categories of Response.

    ERIC Educational Resources Information Center

    Follettie, Joseph F.

    A manipulandum-referenced taxonomy for response categories appropriate to primary education is presented. The tenability of automatic on-line evaluation of the different types of response when processing equipment of the sort that probably will be available to Southwest Regional Laboratory is preliminarily evaluated. (Author/SK)

  11. 40 CFR 265.93 - Preparation, evaluation, and response.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Preparation, evaluation, and response..., STORAGE, AND DISPOSAL FACILITIES Ground-Water Monitoring § 265.93 Preparation, evaluation, and response... the arithmetic mean and variance, based on at least four replicate measurements on each sample,...

  12. Color normalization for robust evaluation of microscopy images

    NASA Astrophysics Data System (ADS)

    Švihlík, Jan; Kybic, Jan; Habart, David

    2015-09-01

    This paper deals with color normalization of microscopy images of Langerhans islets in order to increase robustness of the islet segmentation to illumination changes. The main application is automatic quantitative evaluation of the islet parameters, useful for determining the feasibility of islet transplantation in diabetes. First, background illumination inhomogeneity is compensated and a preliminary foreground/background segmentation is performed. The color normalization itself is done in either lαβ or logarithmic RGB color spaces, by comparison with a reference image. The color-normalized images are segmented using color-based features and pixel-wise logistic regression, trained on manually labeled images. Finally, relevant statistics such as the total islet area are evaluated in order to determine the success likelihood of the transplantation.

  13. Measurement and evaluation techniques for automated demand response demonstration

    SciTech Connect

    Motegi, Naoya; Piette, Mary Ann; Watson, David S.; Sezgen, Osman; ten Hope, Laurie

    2004-08-01

    The recent electricity crisis in California and elsewhere has prompted new research to evaluate demand response strategies in large facilities. This paper describes an evaluation of fully automated demand response technologies (Auto-DR) in five large facilities. Auto-DR does not involve human intervention, but is initiated at a facility through receipt of an external communications signal. This paper summarizes the measurement and evaluation of the performance of demand response technologies and strategies in five large facilities. All the sites have data trending systems such as energy management and control systems (EMCS) and/or energy information systems (EIS). Additional sub-metering was applied where necessary to evaluate the facility's demand response performance. This paper reviews the control responses during the test period, and analyzes demand savings achieved at each site. Occupant comfort issues are investigated where data are available. This paper discusses methods to estimate demand savings and results from demand response strategies at five large facilities.

  14. A biological phantom for evaluation of CT image reconstruction algorithms

    NASA Astrophysics Data System (ADS)

    Cammin, J.; Fung, G. S. K.; Fishman, E. K.; Siewerdsen, J. H.; Stayman, J. W.; Taguchi, K.

    2014-03-01

    In recent years, iterative algorithms have become popular in diagnostic CT imaging to reduce noise or radiation dose to the patient. The non-linear nature of these algorithms leads to non-linearities in the imaging chain. However, the methods to assess the performance of CT imaging systems were developed assuming the linear process of filtered backprojection (FBP). Those methods may not be suitable any longer when applied to non-linear systems. In order to evaluate the imaging performance, a phantom is typically scanned and the image quality is measured using various indices. For reasons of practicality, cost, and durability, those phantoms often consist of simple water containers with uniform cylinder inserts. However, these phantoms do not represent the rich structure and patterns of real tissue accurately. As a result, the measured image quality or detectability performance for lesions may not reflect the performance on clinical images. The discrepancy between estimated and real performance may be even larger for iterative methods which sometimes produce "plastic-like", patchy images with homogeneous patterns. Consequently, more realistic phantoms should be used to assess the performance of iterative algorithms. We designed and constructed a biological phantom consisting of porcine organs and tissue that models a human abdomen, including liver lesions. We scanned the phantom on a clinical CT scanner and compared basic image quality indices between filtered backprojection and an iterative reconstruction algorithm.

  15. [Cardiac magnetic resonance imaging in evaluation of coronary artery disease].

    PubMed

    Bayraktaroğlu, Selen; Alper, Hüdaver

    2008-07-01

    Considerable advances have been achieved in cardiovascular magnetic resonance imaging (MRI) technology, and MRI has become an important noninvasive imaging tool in the management of coronary artery disease. Cardiac MRI can provide information about myocardial perfusion, viability and contractile reserve. The information obtained not only provides diagnostic information but also has an important prognostic value. This article reviews the recent advances in cardiac MRI for evaluation of coronary artery disease. PMID:18611838

  16. Meat quality evaluation by hyperspectral imaging technique: an overview.

    PubMed

    Elmasry, Gamal; Barbin, Douglas F; Sun, Da-Wen; Allen, Paul

    2012-01-01

    During the last two decades, a number of methods have been developed to objectively measure meat quality attributes. Hyperspectral imaging technique as one of these methods has been regarded as a smart and promising analytical tool for analyses conducted in research and industries. Recently there has been a renewed interest in using hyperspectral imaging in quality evaluation of different food products. The main inducement for developing the hyperspectral imaging system is to integrate both spectroscopy and imaging techniques in one system to make direct identification of different components and their spatial distribution in the tested product. By combining spatial and spectral details together, hyperspectral imaging has proved to be a promising technology for objective meat quality evaluation. The literature presented in this paper clearly reveals that hyperspectral imaging approaches have a huge potential for gaining rapid information about the chemical structure and related physical properties of all types of meat. In addition to its ability for effectively quantifying and characterizing quality attributes of some important visual features of meat such as color, quality grade, marbling, maturity, and texture, it is able to measure multiple chemical constituents simultaneously without monotonous sample preparation. Although this technology has not yet been sufficiently exploited in meat process and quality assessment, its potential is promising. Developing a quality evaluation system based on hyperspectral imaging technology to assess the meat quality parameters and to ensure its authentication would bring economical benefits to the meat industry by increasing consumer confidence in the quality of the meat products. This paper provides a detailed overview of the recently developed approaches and latest research efforts exerted in hyperspectral imaging technology developed for evaluating the quality of different meat products and the possibility of its widespread

  17. Study of Fish Response Using Particle Image Velocimetry and High-Speed, High-Resolution Imaging

    SciTech Connect

    Deng, Zhiqun; Richmond, Marshall C.; Guensch, Gregory R.; Mueller, Robert P.

    2004-10-23

    Existing literature of previous particle image velocimetry (PIV) studies of fish swimming has been reviewed. Historically, most of the studies focused on the performance evaluation of freely swimming fish. Technological advances over the last decade, especially the development of digital particle image velocimetry (DPIV) technique, make possible more accurate, quantitative descriptions of the flow patterns adjacent to the fish and in the wake behind the fins and tail, which are imperative to decode the mechanisms of drag reduction and propulsive efficiency. For flows generated by different organisms, the related scales and flow regimes vary significantly. For small Reynolds numbers, viscosity dominates; for very high Reynolds numbers, inertia dominates, and three-dimensional complexity occurs. The majority of previous investigations dealt with the lower end of Reynolds number range. The fish of our interest, such as rainbow trout and spring and fall chinook salmon, fall into the middle range, in which neither viscosity nor inertia is negligible, and three-dimensionality has yet to dominate. Feasibility tests have proven the applicability of PIV to flows around fish. These tests have shown unsteady vortex shedding in the wake, high vorticity region and high stress region, with the highest in the pectoral area. This evident supports the observations by Nietzel et al. (2000) and Deng et al. (2004) that the operculum are most vulnerable to damage from the turbulent shear flow, because they are easily pried open, and the large vorticity and shear stress can lift and tear off scales, rupture or dislodge eyes, and damage gills. In addition, the unsteady behavior of the vortex shedding in the wake implies that injury to fish by the instantaneous flow structures would likely be much higher than the injury level estimated using the average values of the dynamics parameters. Based on existing literature, our technological capability, and relevance and practicability to

  18. Evaluation of Skin Ageing Through Wrinkle Analysis in Capacitive Images

    NASA Astrophysics Data System (ADS)

    Bevilacqua, Alessandro; Gherardi, Alessandro; Guerrieri, Roberto

    Quantitative evaluation of the changes in skin topographic structures are of great importance in the dermocosmetic field to assess subjects response to medical or cosmetic treatments. Although many devices and methods are known to measure these changes, they are not suitable for a routine approach and most of them are invasive. Moreover, it has always been difficult to give a measure of the skin health status as well as of the human aging process by simply analyzing the skin surface appearance. This work describes how a portable capacitive device could be utilized to achieve measurements of skin ageing in vivo and routinely. The capacitive images give a high resolution representation of the skin micro-relief, both in terms of skin surface tissue and wrinkles. In a previous work we dealt with the former; here we have addressed the latter. The algorithm we have developed allowed us to extract two original features from wrinkles: the first is based on photometric properties while the second has been achieved through the multiresolution analysis of the wavelet transform. Accurate experiments accomplished on 87 subjects show how the features we conceived are related to skin ageing.

  19. Accuracy evaluation of airborne stereo line imager data

    NASA Astrophysics Data System (ADS)

    Gibson, J. R.; Chapman, M. A.

    The accuracy of the corrected imagery from a pushbroom stereo line imager is evaluated. The line imager system consists of the MIES II imaging system, an auxiliary data system, and a postflight data-processing system. The imagery and navigation data are tied to ground control points by a photogrammetric bundle adjustment to resolve low-frequency position errors. The accuracy of the correct imagery was found to be 1.5 pixels rms in position and 0.5 pixels rms in height.

  20. Restoration algorithms and system performance evaluation for active imagers

    NASA Astrophysics Data System (ADS)

    Gilles, Jérôme

    2007-10-01

    This paper deals with two fields related to active imaging system. First, we begin to explore image processing algorithms to restore the artefacts like speckle, scintillation and image dancing caused by atmospheric turbulence. Next, we examine how to evaluate the performance of this kind of systems. To do this task, we propose a modified version of the german TRM3 metric which permits to get MTF-like measures. We use the database acquired during NATO-TG40 field trials to make our tests.

  1. Evaluation of color error and noise on simulated images

    NASA Astrophysics Data System (ADS)

    Mornet, Clémence; Vaillant, Jérôme; Decroux, Thomas; Hérault, Didier; Schanen, Isabelle

    2010-01-01

    The evaluation of CMOS sensors performance in terms of color accuracy and noise is a big challenge for camera phone manufacturers. On this paper, we present a tool developed with Matlab at STMicroelectronics which allows quality parameters to be evaluated on simulated images. These images are computed based on measured or predicted Quantum Efficiency (QE) curves and noise model. By setting the parameters of integration time and illumination, the tool optimizes the color correction matrix (CCM) and calculates the color error, color saturation and signal-to-noise ratio (SNR). After this color correction optimization step, a Graphics User Interface (GUI) has been designed to display a simulated image at a chosen illumination level, with all the characteristics of a real image taken by the sensor with the previous color correction. Simulated images can be a synthetic Macbeth ColorChecker, for which reflectance of each patch is known, or a multi-spectral image, described by the reflectance spectrum of each pixel or an image taken at high-light level. A validation of the results has been performed with ST under development sensors. Finally we present two applications one based on the trade-offs between color saturation and noise by optimizing the CCM and the other based on demosaicking SNR trade-offs.

  2. Evaluation of clinical image processing algorithms used in digital mammography.

    PubMed

    Zanca, Federica; Jacobs, Jurgen; Van Ongeval, Chantal; Claus, Filip; Celis, Valerie; Geniets, Catherine; Provost, Veerle; Pauwels, Herman; Marchal, Guy; Bosmans, Hilde

    2009-03-01

    Screening is the only proven approach to reduce the mortality of breast cancer, but significant numbers of breast cancers remain undetected even when all quality assurance guidelines are implemented. With the increasing adoption of digital mammography systems, image processing may be a key factor in the imaging chain. Although to our knowledge statistically significant effects of manufacturer-recommended image processings have not been previously demonstrated, the subjective experience of our radiologists, that the apparent image quality can vary considerably between different algorithms, motivated this study. This article addresses the impact of five such algorithms on the detection of clusters of microcalcifications. A database of unprocessed (raw) images of 200 normal digital mammograms, acquired with the Siemens Novation DR, was collected retrospectively. Realistic simulated microcalcification clusters were inserted in half of the unprocessed images. All unprocessed images were subsequently processed with five manufacturer-recommended image processing algorithms (Agfa Musica 1, IMS Raffaello Mammo 1.2, Sectra Mamea AB Sigmoid, Siemens OPVIEW v2, and Siemens OPVIEW v1). Four breast imaging radiologists were asked to locate and score the clusters in each image on a five point rating scale. The free-response data were analyzed by the jackknife free-response receiver operating characteristic (JAFROC) method and, for comparison, also with the receiver operating characteristic (ROC) method. JAFROC analysis revealed highly significant differences between the image processings (F = 8.51, p < 0.0001), suggesting that image processing strongly impacts the detectability of clusters. Siemens OPVIEW2 and Siemens OPVIEW1 yielded the highest and lowest performances, respectively. ROC analysis of the data also revealed significant differences between the processing but at lower significance (F = 3.47, p = 0.0305) than JAFROC. Both statistical analysis methods revealed that the

  3. Semiautomatic detection and evaluation of autofluorescent areas in retinal images.

    PubMed

    Kolár, Radim; Jan, Jirí; Laemmer, Robert; Jirík, Radovan

    2007-01-01

    A semiautomatic approach to the detection and evaluation of the autofluorescent zones in retinal images, recognized as having a diagnostic value, has been designed based on fusing information from two Heidelberg Retina Angiograph imaging modalities - autofluorescent and infrared modes. The procedure, initiated by automatic preprocessing and region-of-interest determination continues by manually initiated segmentation via constrained region growing and ends with evaluating the size and geometrical coordinates of the AF regions with respect to the centre of the optic disc. Results are compared with those obtained by experienced ophthalmologists. PMID:18002708

  4. Mode imaging and loss evaluation of semiconductor waveguides

    SciTech Connect

    Mochizuki, Toshimitsu; Kim, Changsu; Yoshita, Masahiro; Nakamura, Takahiro; Akiyama, Hidefumi; Pfeiffer, Loren N.; West, Ken W.

    2014-05-15

    An imaging and loss evaluation method for semiconductor waveguides coupled with non-doped quantum wells is presented. Using the internal emission of the wells as a probe light source, the numbers and widths of the modes of waveguides with various ridge sizes were evaluated by CCD imaging, and the obtained values were consistent with effective index method calculation. Waveguide internal losses were obtained from analyses of the Fabry-Pérot fringes of waveguide emission spectra. We quantified the quality of 29 single-mode waveguide samples as an internal loss and variation of 10.2 ± 0.6  cm{sup −1}.

  5. Can imaging patterns of neuroendocrine hepatic metastases predict response yttruim-90 radioembolotherapy?

    PubMed Central

    Neperud, Julia; Mahvash, Armeen; Garg, Naveen; Murthy, Ravi; Szklaruk, Janio

    2013-01-01

    AIM: To evaluate the response to treatment in patients with neuroendocrine tumor liver metastases following yttrium-90 (90Y) radioembolotherapy, as a function of image patterns at presentation for 90Y radioembolotherapy. METHODS: The study cohort consisted of patients with hepatic metastatic neuroendocrine tumors treated with 90Y at our institution during a two-year time period. Hepatic metastases were evaluated on a pre-therapy study assessing relative arterial enhancement compared to liver, lesion size, necrosis of the lesion, and associated tumor burden in the liver. We used six response criteria: Response Evaluation Criteria in Solid Tumors (RECIST) size, World Health Organization (WHO) size, European Association for the Study of the Liver (EASL) necrosis guidelines, Choi size, Choi necrosis and combination of Choi size and necrosis. RESULTS: About 65 lesions in 17 patients met study criteria and formed the cohort. Statistically significant response was found for lesions < 5 cm vs those ≥ 5 cm with RECIST (P = 0.04), WHO (P = 0.002) and combined Choi criteria (P = 0.02). Hyperenhancing lesions demonstrated greater response only with the Choi size criteria (P = 0.04). Lesions with ≤ 50% necrosis on the pre-scan had statistically significant greater response with the Choi necrosis criteria (P = 0.01). There was no statistical significance for response comparing lesions < 2 cm vs ≥ 2 cm or in comparing the degrees of tumor burden. CONCLUSION: Based on our findings in this study, it is suggested that initial imaging findings, as listed above, are not a good predictor of response to 90Y radioembolization. PMID:23807902

  6. An evaluation of sharpness in different image displays used for medical imaging

    NASA Astrophysics Data System (ADS)

    Ukishima, Masayuki; Nakaguchi, Toshiya; Kato, Katsushi; Fukuchi, Yoshikazu; Tsumura, Norimichi; Matsumoto, Kazumasa; Yanagawa, Noriyuki; Ogura, Takashi; Kikawa, Takashi; Miyake, Yoichi

    2006-01-01

    X-ray film systems have been widely used for a diagnosis of various diseases since a long time ago. In recent years, many kinds of displays and recording systems for X-ray medical images have been used including inkjet printer, silver halide film, CRT and LCD, by the development of the digital X-ray image capturing systems. In this paper, image quality of X-ray images displayed onto high accurate monochrome CRT and LCD monitors are analyzed and compared. Images recorded on the exclusive film and coated paper by inkjet printer and the wet type and dry type photo printers using a silver halide material are also analyzed and compared. The modified Gan's method is introduced to calculate the MTF (Modulation Transfer Function) from the knife ESF (edge spread function). The results show that the MTFs of the inkjet image on the transparency and the wet type silver halide film image have fairly similar and good response in comparison with the inkjet image on the coated paper and the dry type silver halide film. It is also shown that the CRT has the worse response over the spatial frequency range. It was well correlated between the MTF and observer rating value. From here, we consider the proposed method is effective.

  7. Digital imaging approaches for phenotyping whole plant nitrogen and phosphorus response in Brachypodium distachyon.

    PubMed

    Poiré, Richard; Chochois, Vincent; Sirault, Xavier R R; Vogel, John P; Watt, Michelle; Furbank, Robert T

    2014-08-01

    This work evaluates the phenotypic response of the model grass (Brachypodium distachyon (L.) P. Beauv.) to nitrogen and phosphorus nutrition using a combination of imaging techniques and destructive harvest of shoots and roots. Reference line Bd21-3 was grown in pots using 11 phosphorus and 11 nitrogen concentrations to establish a dose-response curve. Shoot biovolume and biomass, root length and biomass, and tissue phosphorus and nitrogen concentrations increased with nutrient concentration. Shoot biovolume, estimated by imaging, was highly correlated with dry weight (R(2) > 0.92) and both biovolume and growth rate responded strongly to nutrient availability. Higher nutrient supply increased nodal root length more than other root types. Photochemical efficiency was strongly reduced by low phosphorus concentrations as early as 1 week after germination, suggesting that this measurement may be suitable for high throughput screening of phosphorus response. In contrast, nitrogen concentration had little effect on photochemical efficiency. Changes in biovolume over time were used to compare growth rates of four accessions in response to nitrogen and phosphorus supply. We demonstrate that a time series image-based approach coupled with mathematical modeling provides higher resolution of genotypic response to nutrient supply than traditional destructive techniques and shows promise for high throughput screening and determination of genomic regions associated with superior nutrient use efficiency. PMID:24666962

  8. Evaluation of image quality of a new CCD-based system for chest imaging

    NASA Astrophysics Data System (ADS)

    Sund, Patrik; Kheddache, Susanne; Mansson, Lars G.; Bath, Magnus; Tylen, Ulf

    2000-04-01

    The Imix radiography system (Qy Imix Ab, Finland)consists of an intensifying screen, optics, and a CCD camera. An upgrade of this system (Imix 2000) with a red-emitting screen and new optics has recently been released. The image quality of Imix (original version), Imix 200, and two storage-phosphor systems, Fuji FCR 9501 and Agfa ADC70 was evaluated in physical terms (DQE) and with visual grading of the visibility of anatomical structures in clinical images (141 kV). PA chest images of 50 healthy volunteers were evaluated by experienced radiologists. All images were evaluated on Siemens Simomed monitors, using the European Quality Criteria. The maximum DQE values for Imix, Imix 2000, Agfa and Fuji were 11%, 14%, 17% and 19%, respectively (141kV, 5μGy). Using the visual grading, the observers rated the systems in the following descending order. Fuji, Imix 2000, Agfa, and Imix. Thus, the upgrade to Imix 2000 resulted in higher DQE values and a significant improvement in clinical image quality. The visual grading agrees reasonably well with the DQE results; however, Imix 2000 received a better score than what could be expected from the DQE measurements. Keywords: CCD Technique, Chest Imaging, Digital Radiography, DQE, Image Quality, Visual Grading Analysis

  9. Evaluation of back projection methods for breast tomosynthesis image reconstruction.

    PubMed

    Zhou, Weihua; Lu, Jianping; Zhou, Otto; Chen, Ying

    2015-06-01

    Breast cancer is the most common cancer among women in the USA. Compared to mammography, digital breast tomosynthesis is a new imaging technique that may improve the diagnostic accuracy by removing the ambiguities of overlapped tissues and providing 3D information of the breast. Tomosynthesis reconstruction algorithms generate 3D reconstructed slices from a few limited angle projection images. Among different reconstruction algorithms, back projection (BP) is considered an important foundation of quite a few reconstruction techniques with deblurring algorithms such as filtered back projection. In this paper, two BP variants, including α-trimmed BP and principal component analysis-based BP, were proposed to improve the image quality against that of traditional BP. Computer simulations and phantom studies demonstrated that the α-trimmed BP may improve signal response performance and suppress noise in breast tomosynthesis image reconstruction. PMID:25384538

  10. Development and validation of experimental models for hyperemic thermal response using IR imaging

    NASA Astrophysics Data System (ADS)

    Moreno, Eulalia; Hsieh, Sheng-Jen; Palomares, Benjamin Giron

    2012-06-01

    A common method for diagnosing heart health condition is to analyze blood flow rate and temperature behaviors after arterial occlusion. However, multiple factors besides heart condition could affect these behaviors. The objective of this research was to identify other factors that affect blood flow and thermal response after arterial occlusion, evaluate a mathematical model to determine thermal response after arterial occlusion, and develop an experimental model for thermal response after arterial occlusion. Twenty-eight experiments were conducted with 14 subjects to determine blood and thermal responses by using plethysmography and infrared imaging after applying arterial occlusion. Possible factors affecting blood flow and thermal responses that were investigated were: Initial finger temperature, blood pressure, body temperature, gender, and age. After determining the correlation coefficient among the mentioned factors and blood flow and thermal responses after occlusion, it was determined that only initial finger temperature and blood pressure show a strong effect. A mathematical model accounting only for the convective thermal effects, but not thermal conduction effects, was developed and tested, but was found to be insufficiently accurate in describing the thermal response by means of blood flow parameters for all of the subjects tested (error>90%). A linear regression model was then developed to relate blood flow to thermal response using two thirds of the experimental data, and was tested using one third of the data. The linear regression model was found to predict thermal response by means of blood flow response with an error rate of less than 50%.

  11. Evaluation of chirp reversal power modulation sequence for contrast agent imaging

    NASA Astrophysics Data System (ADS)

    Novell, A.; Sennoga, CA; Escoffre, JM; Chaline, J.; Bouakaz, A.

    2014-09-01

    Over the last decade, significant research effort has been focused on the use of chirp for contrast agent imaging because chirps are known to significantly increase imaging contrast-to-noise ratio (CNR). New imaging schemes, such as chirp reversal (CR), have been developed to improve contrast detection by increasing non-linear microbubble responses. In this study we evaluated the contrast enhancement efficiency of various chirped imaging sequences in combination with well-established imaging schemes such as power modulation (PM) and pulse inversion (PI). The imaging schemes tested were implemented on a fully programmable open scanner and evaluated by ultrasonically scanning (excitation frequency of 2.5 MHz amplitude of 350 kPa) a tissue-mimicking flow phantom comprising a 4 mm diameter tube through which aqueous dispersions (dilution fraction of 1/2000) of the commercial ultrasound contrast agent, SonoVue® were continuously circulated. The recovery of non-linear microbubble responses after chirp compression requires the development and the optimization of a specific filter. A compression filter was therefore designed and used to compress and extract several non-linear components from the received microbubble responses. The results showed that using chirps increased the image CNR by approximately 10 dB, as compared to conventional Gaussian apodized sine burst excitation but degraded the axial resolution by a factor of 1.4, at -3 dB. We demonstrated that the highest CNR and contrast-to-noise ratio (CTR) were achievable when CR was combined with PM as compared to other imaging schemes such as PI.

  12. An Automated Image Processing System for Concrete Evaluation

    SciTech Connect

    Baumgart, C.W.; Cave, S.P.; Linder, K.E.

    1998-11-23

    AlliedSignal Federal Manufacturing & Technologies (FM&T) was asked to perform a proof-of-concept study for the Missouri Highway and Transportation Department (MHTD), Research Division, in June 1997. The goal of this proof-of-concept study was to ascertain if automated scanning and imaging techniques might be applied effectively to the problem of concrete evaluation. In the current evaluation process, a concrete sample core is manually scanned under a microscope. Voids (or air spaces) within the concrete are then detected visually by a human operator by incrementing the sample under the cross-hairs of a microscope and by counting the number of "pixels" which fall within a void. Automation of the scanning and image analysis processes is desired to improve the speed of the scanning process, to improve evaluation consistency, and to reduce operator fatigue. An initial, proof-of-concept image analysis approach was successfully developed and demonstrated using acquired black and white imagery of concrete samples. In this paper, the automated scanning and image capture system currently under development will be described and the image processing approach developed for the proof-of-concept study will be demonstrated. A development update and plans for future enhancements are also presented.

  13. Computerized quantitative evaluation of mammographic accreditation phantom images

    SciTech Connect

    Lee, Yongbum; Tsai, Du-Yih; Shinohara, Norimitsu

    2010-12-15

    Purpose: The objective was to develop and investigate an automated scoring scheme of the American College of Radiology (ACR) mammographic accreditation phantom (RMI 156, Middleton, WI) images. Methods: The developed method consisted of background subtraction, determination of region of interest, classification of fiber and mass objects by Mahalanobis distance, detection of specks by template matching, and rule-based scoring. Fifty-one phantom images were collected from 51 facilities for this study (one facility provided one image). A medical physicist and two radiologic technologists also scored the images. The human and computerized scores were compared. Results: In terms of meeting the ACR's criteria, the accuracies of the developed method for computerized evaluation of fiber, mass, and speck were 90%, 80%, and 98%, respectively. Contingency table analysis revealed significant association between observer and computer scores for microcalcifications (p<5%) but not for masses and fibers. Conclusions: The developed method may achieve a stable assessment of visibility for test objects in mammographic accreditation phantom image in whether the phantom image meets the ACR's criteria in the evaluation test, although there is room left for improvement in the approach for fiber and mass objects.

  14. Evaluation of image deblurring methods via a classification metric

    NASA Astrophysics Data System (ADS)

    Perrone, Daniele; Humphreys, David; Lamb, Robert A.; Favaro, Paolo

    2012-09-01

    The performance of single image deblurring algorithms is typically evaluated via a certain discrepancy measure between the reconstructed image and the ideal sharp image. The choice of metric, however, has been a source of debate and has also led to alternative metrics based on human visual perception. While fixed metrics may fail to capture some small but visible artifacts, perception-based metrics may favor reconstructions with artifacts that are visually pleasant. To overcome these limitations, we propose to assess the quality of reconstructed images via a task-driven metric. In this paper we consider object classification as the task and therefore use the rate of classification as the metric to measure deblurring performance. In our evaluation we use data with different types of blur in two cases: Optical Character Recognition (OCR), where the goal is to recognise characters in a black and white image, and object classification with no restrictions on pose, illumination and orientation. Finally, we show how off-the-shelf classification algorithms benefit from working with deblurred images.

  15. Radiometric quality evaluation of ZY-02C satellite panchromatic image

    NASA Astrophysics Data System (ADS)

    Zhao, Fengfan; Sun, Ke; Yang, Lei

    2014-11-01

    As the second Chinese civilian high spatial resolution satellite, the ZY-02C satellite was successfully launched on December 22, 2011. In this paper, we used two different methods, subjective evaluation and external evaluation, to evaluate radiation quality of ZY-02C panchromatic image, meanwhile, we compared with quality of CBERS-02B, SPOT-5 satellite. The external evaluation could give us quantitative image quality. The EIFOV of ZY-02C, one of parameters, is less than SPOT-5. The results demonstrate the spatial resolution of ZY-02C is greater than SPOT-5. The subjective results show that the quality of SPOT-5 is little preferable to ZY-02C - CBERS-02B, and the quality of ZY-02C is better than CBERS-02B for most land-cover types. The results in the subjective evaluation and the external evaluation show the excellent agreement. Therefore the comprehensive result of the image quality will be got based on combining parameters introduced in this paper.

  16. Evaluating Detection and Diagnostic Decision Support Systems for Bioterrorism Response

    PubMed Central

    Sundaram, Vandana; McDonald, Kathryn M.; Smith, Wendy M.; Szeto, Herbert; Schleinitz, Mark D.; Owens, Douglas K.

    2004-01-01

    We evaluated the usefulness of detection systems and diagnostic decision support systems for bioterrorism response. We performed a systematic review by searching relevant databases (e.g., MEDLINE) and Web sites for reports of detection systems and diagnostic decision support systems that could be used during bioterrorism responses. We reviewed over 24,000 citations and identified 55 detection systems and 23 diagnostic decision support systems. Only 35 systems have been evaluated: 4 reported both sensitivity and specificity, 13 were compared to a reference standard, and 31 were evaluated for their timeliness. Most evaluations of detection systems and some evaluations of diagnostic systems for bioterrorism responses are critically deficient. Because false-positive and false-negative rates are unknown for most systems, decision making on the basis of these systems is seriously compromised. We describe a framework for the design of future evaluations of such systems. PMID:15078604

  17. SU-E-J-148: Evaluating Tumor Response with a Commercially Available Deformable Registration System

    SciTech Connect

    Bowling, J; Ramsey, C

    2014-06-01

    Purpose: The purpose of this study is to present a method for evaluating the response to treatment using a commercially available deformable image registration software package (Velocity Medical Systems) and repeat PET/CT imaging. This technique can be used to identify volumes that are risk for tumor recurrence. Methods: Response to treatment was evaluated using PET/CT images acquired prior-to and post-treatment for radiation therapy patients treated with concurrent chemotherapy. Velocity (Version 3.0.1) was used to deform the initial PET/CT to the post treatment PET/CT. The post-treatment PET images were then subtracted from the pre-treatment PET images. The resulting re-sampled image is a three-dimensional SUV difference map that shows pixels with increasing SUV values. SUV values increases greater than 2.5 in the post treatment images were identified for additional follow-up. Results: A total of 5 Lung patients were analyzed as part of this study. One lung patient in the cohort had an SUV increase of +3.28 that was identified using the SUV difference map. This volume of increased uptake was located outside the treatment field and adjacent to the 35 Gy isodose line. The remaining four patients all had SUV decreases inside the planning target volume, and no unexpected areas of increase outside the irradiated volumes. All five patients were analyzed using standard tools inside the Velocity application. Conclusion: The response to treatment can easily be measured using serial PET/CT images and a commercially available deformable image registration. This provides both the radiation oncologists and medical oncologists with a quantitative assessment of their treatment to use in patient follow-up.

  18. Applied methods of testing and evaluation for IR imaging system

    NASA Astrophysics Data System (ADS)

    Liao, Xiao-yue; Lu, Jin

    2009-07-01

    Different methods of testing and evaluation for IR imaging system are used with the application of the 2nd and the 3rd generation infrared detectors. The performance of IR imaging system can be reflected by many specifications, such as Noise Equivalent Temperature Difference (NETD), Nonuniformity, system Modulation Transfer Function (MTF), Minimum Resolvable Temperature Difference (MRTD), and Minimum Detectable Temperature Difference (MRTD) etc. The sensitivity of IR sensors is estimated by NETD. The sensitivity of thermal imaging sensors and space resolution are evaluated by MRTD, which is the chief specification of system. In this paper, the theoretical analysis of different testing methods is introduced. The characteristics of them are analyzed and compared. Based on discussing the factors that affect measurement results, an applied method of testing NETD and MRTD for IR system is proposed.

  19. Evaluation of Matching Strategies for Image-Based Mobile Mapping

    NASA Astrophysics Data System (ADS)

    Cavegn, S.; Haala, N.; Nebiker, S.; Rothermel, M.; Zwölfer, T.

    2015-08-01

    The paper presents the implementation of a dense multi-view stereo matching pipeline for the evaluation of image sequences from a camera-based mobile mapping system. For this purpose the software system SURE is taken as a basis. Originally this system was developed to provide 3D point clouds or DEM from standard airborne and terrestrial image blocks. Since mobile mapping scenarios typically include stereo configurations with camera motion predominantly in viewing direction, processing steps like image rectification and structure computation of the existing processing pipeline had to be adapted. The presented investigations are based on imagery captured by the mobile mapping system of the Institute of Geomatics Engineering in the city center of Basel, Switzerland. For evaluation, reference point clouds from terrestrial laser scanning are used. Our first results already demonstrate a considerable increase in reliability and completeness of both depth maps and point clouds as result of the matching process.

  20. Radionuclide imaging in the evaluation of osteomyelitis and septic arthritis

    SciTech Connect

    Kim, E.E.; Haynie, T.P.; Podoloff, D.A.; Lowry, P.A.; Harle, T.S. )

    1989-01-01

    Despite controversy over its exact role, radionuclide imaging plays an important role in the evaluation of patients suspected of having osteomyelitis. The differentiation between osteomyelitis and cellulitis is best accomplished by using a three-phase technique using Tc-99m methylene diphosphonate (MDP). Frequently, it is necessary to obtain multiple projections and magnification views to adequately assess suspected areas. It is recommended that a Ga-67 or In-111 leukocyte scan be performed in those cases where osteomyelitis is strongly suspected clinically and the routine bone scan is equivocal or normal. Repeated bone scan after 48 to 72 h may demonstrate increased radioactivity in the case of early osteomyelitis with the initial photon-deficient lesion. In-111 leukocyte imaging is useful for the evaluation of suspected osteomyelitis complicating recent fracture or operation, but must be used in conjunction with clinical and radiographic correlation. The recognition of certain imaging patterns appears helpful to separate osteomyelitis from septic arthritis or cellulitis. 83 references.

  1. Image processing system performance prediction and product quality evaluation

    NASA Technical Reports Server (NTRS)

    Stein, E. K.; Hammill, H. B. (Principal Investigator)

    1976-01-01

    The author has identified the following significant results. A new technique for image processing system performance prediction and product quality evaluation was developed. It was entirely objective, quantitative, and general, and should prove useful in system design and quality control. The technique and its application to determination of quality control procedures for the Earth Resources Technology Satellite NASA Data Processing Facility are described.

  2. Evaluation of physiological status of potato tubers using hyperspectral imaging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Visible and near-infrared hyperspectral reflectance imaging was evaluated as a rapid technique to predict the glucose and sucrose percentages in two common fresh use and chipping potato cultivars. Tubers were sampled in the 2009 season and held in multiple storage temperatures in attempt to develop ...

  3. Metabolic Imaging to Assess Treatment Response to Cytotoxic and Cytostatic Agents

    PubMed Central

    Serkova, Natalie J.; Eckhardt, S. Gail

    2016-01-01

    For several decades, cytotoxic chemotherapeutic agents were considered the basis of anticancer treatment for patients with metastatic tumors. A decrease in tumor burden, assessed by volumetric computed tomography and magnetic resonance imaging, according to the response evaluation criteria in solid tumors (RECIST), was considered as a radiological response to cytotoxic chemotherapies. In addition to RECIST-based dimensional measurements, a metabolic response to cytotoxic drugs can be assessed by positron emission tomography (PET) using 18F-fluoro-thymidine (FLT) as a radioactive tracer for drug-disrupted DNA synthesis. The decreased 18FLT-PET uptake is often seen concurrently with increased apparent diffusion coefficients by diffusion-weighted imaging due to chemotherapy-induced changes in tumor cellularity. Recently, the discovery of molecular origins of tumorogenesis led to the introduction of novel signal transduction inhibitors (STIs). STIs are targeted cytostatic agents; their effect is based on a specific biological inhibition with no immediate cell death. As such, tumor size is not anymore a sensitive end point for a treatment response to STIs; novel physiological imaging end points are desirable. For receptor tyrosine kinase inhibitors as well as modulators of the downstream signaling pathways, an almost immediate inhibition in glycolytic activity (the Warburg effect) and phospholipid turnover (the Kennedy pathway) has been seen by metabolic imaging in the first 24 h of treatment. The quantitative imaging end points by magnetic resonance spectroscopy and metabolic PET (including 18F-fluoro-deoxy-glucose, FDG, and total choline) provide an early treatment response to targeted STIs, before a reduction in tumor burden can be seen. PMID:27471678

  4. Evaluation of digital halftones image by vector error diffusion

    NASA Astrophysics Data System (ADS)

    Kouzaki, Masahiro; Itoh, Tetsuya; Kawaguchi, Takayuki; Tsumura, Norimichi; Haneishi, Hideaki; Miyake, Yoichi

    1998-12-01

    The vector error diffusion (VED) method is applied to proudce the digital halftone images by an electrophotographic printer with 600 dpi. Objective image quality of those obtained images is evaluated and analyzed. As a result, in the color reproduction of halftone image by the VED method, it was clear that there are large color difference between target color and printed color typically in the mid-tone colors. We consider it is due to the printer properties including dot-gain. It was also clear that the color noise of the VED method is larger compared with that of the conventional scalar error diffusion method in some patches. It was remarkable that ununiform patterns are generated by the VED method.

  5. Evaluation of Skybox Video and Still Image products

    NASA Astrophysics Data System (ADS)

    d'Angelo, P.; Kuschk, G.; Reinartz, P.

    2014-11-01

    The SkySat-1 satellite lauched by Skybox Imaging on November 21 in 2013 opens a new chapter in civilian earth observation as it is the first civilian satellite to image a target in high definition panchromatic video for up to 90 seconds. The small satellite with a mass of 100 kg carries a telescope with 3 frame sensors. Two products are available: Panchromatic video with a resolution of around 1 meter and a frame size of 2560 × 1080 pixels at 30 frames per second. Additionally, the satellite can collect still imagery with a swath of 8 km in the panchromatic band, and multispectral images with 4 bands. Using super-resolution techniques, sub-meter accuracy is reached for the still imagery. The paper provides an overview of the satellite design and imaging products. The still imagery product consists of 3 stripes of frame images with a footprint of approximately 2.6 × 1.1 km. Using bundle block adjustment, the frames are registered, and their accuracy is evaluated. Image quality of the panchromatic, multispectral and pansharpened products are evaluated. The video product used in this evaluation consists of a 60 second gazing acquisition of Las Vegas. A DSM is generated by dense stereo matching. Multiple techniques such as pairwise matching or multi image matching are used and compared. As no ground truth height reference model is availble to the authors, comparisons on flat surface and compare differently matched DSMs are performed. Additionally, visual inspection of DSM and DSM profiles show a detailed reconstruction of small features and large skyscrapers.

  6. Diagnostic imaging of pancreatic neuroendocrine neoplasms (pNEN): tumor detection, staging, prognosis, and response to treatment.

    PubMed

    Baur, Alexander D J; Pavel, Marianne; Prasad, Vikas; Denecke, Timm

    2016-03-01

    Pancreatic neuroendocrine neoplasms (pNEN) are rare malignancies arising from neuroendocrine cells of the pancreas. Functional tumors can present with specific clinical syndromes due to hormonal secretion. These tumors can present as incidental findings on imaging performed for unrelated purposes or they are diagnosed when workup is initiated in patients with specific syndromes or metastases. This article presents an overview of available imaging techniques focusing on computed tomography and magnetic resonance imaging. Recommendations regarding examination protocols are given. Typical imaging features of pNEN and metastases are described. Their potential value for the evaluation of prognosis as well as tumor response under treatment is discussed. PMID:25855665

  7. Evaluating method for the double image phenomenon of LED lighting

    NASA Astrophysics Data System (ADS)

    Wu, Wen-Hong; Kuo, Chao-Hui; Hung, Min-Wei; Huang, Kuo-Cheng

    In recent years, the overriding advantages long life, high efficiency, small size and short reaction time have made LED become a viable alternative to conventional light sources. LED lighting sources are usually composed of several individual LED cells which must be mounted on a panel as a lighting module. Being composed of several individual LED cells, the LED sources will cause the double image phenomenon. The double image phenomenon is more obvious when the LED sources are more closer, such as LED table lamp, and limits the applications of LED sources. By using a proper secondary optical lens, the double image phenomenon can be reduced. In this research, an evaluating method based on image processing is developed for the double image phenomenon of a LED sources. By analyzing the gray-scale of the grabbed image which is obtained by putting a rob under a LED source, an index of double image can be established and be a criterion to judge different LED sources. Furthermore, a series of LED lighting simulations are shown in this paper and several type of secondary optical lens are compared and discussed in this paper as well.

  8. An automated deformable image registration evaluation of confidence tool.

    PubMed

    Kirby, Neil; Chen, Josephine; Kim, Hojin; Morin, Olivier; Nie, Ke; Pouliot, Jean

    2016-04-21

    Deformable image registration (DIR) is a powerful tool for radiation oncology, but it can produce errors. Beyond this, DIR accuracy is not a fixed quantity and varies on a case-by-case basis. The purpose of this study is to explore the possibility of an automated program to create a patient- and voxel-specific evaluation of DIR accuracy. AUTODIRECT is a software tool that was developed to perform this evaluation for the application of a clinical DIR algorithm to a set of patient images. In brief, AUTODIRECT uses algorithms to generate deformations and applies them to these images (along with processing) to generate sets of test images, with known deformations that are similar to the actual ones and with realistic noise properties. The clinical DIR algorithm is applied to these test image sets (currently 4). From these tests, AUTODIRECT generates spatial and dose uncertainty estimates for each image voxel based on a Student's t distribution. In this study, four commercially available DIR algorithms were used to deform a dose distribution associated with a virtual pelvic phantom image set, and AUTODIRECT was used to generate dose uncertainty estimates for each deformation. The virtual phantom image set has a known ground-truth deformation, so the true dose-warping errors of the DIR algorithms were also known. AUTODIRECT predicted error patterns that closely matched the actual error spatial distribution. On average AUTODIRECT overestimated the magnitude of the dose errors, but tuning the AUTODIRECT algorithms should improve agreement. This proof-of-principle test demonstrates the potential for the AUTODIRECT algorithm as an empirical method to predict DIR errors. PMID:27025957

  9. An automated deformable image registration evaluation of confidence tool

    NASA Astrophysics Data System (ADS)

    Kirby, Neil; Chen, Josephine; Kim, Hojin; Morin, Olivier; Nie, Ke; Pouliot, Jean

    2016-04-01

    Deformable image registration (DIR) is a powerful tool for radiation oncology, but it can produce errors. Beyond this, DIR accuracy is not a fixed quantity and varies on a case-by-case basis. The purpose of this study is to explore the possibility of an automated program to create a patient- and voxel-specific evaluation of DIR accuracy. AUTODIRECT is a software tool that was developed to perform this evaluation for the application of a clinical DIR algorithm to a set of patient images. In brief, AUTODIRECT uses algorithms to generate deformations and applies them to these images (along with processing) to generate sets of test images, with known deformations that are similar to the actual ones and with realistic noise properties. The clinical DIR algorithm is applied to these test image sets (currently 4). From these tests, AUTODIRECT generates spatial and dose uncertainty estimates for each image voxel based on a Student’s t distribution. In this study, four commercially available DIR algorithms were used to deform a dose distribution associated with a virtual pelvic phantom image set, and AUTODIRECT was used to generate dose uncertainty estimates for each deformation. The virtual phantom image set has a known ground-truth deformation, so the true dose-warping errors of the DIR algorithms were also known. AUTODIRECT predicted error patterns that closely matched the actual error spatial distribution. On average AUTODIRECT overestimated the magnitude of the dose errors, but tuning the AUTODIRECT algorithms should improve agreement. This proof-of-principle test demonstrates the potential for the AUTODIRECT algorithm as an empirical method to predict DIR errors.

  10. Current and Future Trends in Magnetic Resonance Imaging Assessments of the Response of Breast Tumors to Neoadjuvant Chemotherapy

    PubMed Central

    Arlinghaus, Lori R.; Li, Xia; Levy, Mia; Smith, David; Welch, E. Brian; Gore, John C.; Yankeelov, Thomas E.

    2010-01-01

    The current state-of-the-art assessment of treatment response in breast cancer is based on the response evaluation criteria in solid tumors (RECIST). RECIST reports on changes in gross morphology and divides response into one of four categories. In this paper we highlight how dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted MRI (DW-MRI) may be able to offer earlier, and more precise, information on treatment response in the neoadjuvant setting than RECIST. We then describe how longitudinal registration of breast images and the incorporation of intelligent bioinformatics approaches with imaging data have the potential to increase the sensitivity of assessing treatment response. We conclude with a discussion of the potential benefits of breast MRI at the higher field strength of 3T. For each of these areas, we provide a review, illustrative examples from clinical trials, and offer insights into future research directions. PMID:20953332

  11. Development of a Multiparametric Voxel-Based Magnetic Resonance Imaging Biomarker for Early Cancer Therapeutic Response Assessment

    PubMed Central

    Galbán, Craig J.; Lemasson, Benjamin; Hoff, Benjamin A.; Johnson, Timothy D.; Sundgren, Pia C.; Tsien, Christina; Chenevert, Thomas L.; Ross, Brian D.

    2015-01-01

    Quantitative magnetic resonance imaging (MRI)-based biomarkers, which capture physiological and functional tumor processes, were evaluated as imaging surrogates of early tumor response following chemoradiotherapy in glioma patients. A multiparametric extension of a voxel-based analysis, referred as the parametric response map (PRM), was applied to quantitative MRI maps to test the predictive potential of this metric for detecting response. Fifty-six subjects with newly diagnosed high-grade gliomas treated with radiation and concurrent temozolomide were enrolled in a single-site prospective institutional review board-approved MRI study. Apparent diffusion coefficient (ADC) and relative cerebral blood volume (rCBV) maps were acquired before therapy and 3 weeks after therapy was initiated. Multiparametric PRM (mPRM) was applied to both physiological MRI maps and evaluated as an imaging biomarker of patient survival. For comparison, single-biomarker PRMs were also evaluated in this study. The simultaneous analysis of ADC and rCBV by the mPRM approach was found to improve the predictive potential for patient survival over single PRM measures. With an array of quantitative imaging parameters being evaluated as biomarkers of therapeutic response, mPRM shows promise as a new methodology for consolidating physiologically distinct imaging parameters into a single interpretable and quantitative metric. PMID:26568982

  12. Comparison of retinal image evaluation techniques in novice clinicians

    PubMed Central

    Putnam, Christopher M.; Permann, Alex; Bassi, Carl J.

    2015-01-01

    Abstract. Retinal fundus evaluation is learned through experience and training. This study aimed to determine the image presentation characteristics and the accompanying evaluation techniques, which led to the most accurate and efficient retinal pathology detection method. Phase I included 25 novice clinicians asked to evaluate 14 different pathologies using spatial versus temporal image presentations. Phase II included 25 different novice clinicians asked to evaluate five different simulated pathologies at three different pixel sizes presented in both spatial and temporal image presentations. Accuracy and speed of recognition were evaluated between the spatial and temporal presentations of the same simulated pathology. In phase l, subjects were significantly faster at simulated pathology detection using a temporal presentation with a 95% accuracy rate versus a spatial presentation with a 79% accuracy rate. In phase II, subjects demonstrated significant differences in speed of detection using the temporal technique at all 3 pixel number sizes with the greatest difference in detection times shown at the smallest retinal defects. Accuracy and speed of recognition in simulated pathology assessment were improved in a temporal presentation and the greatest improvements were demonstrated at the smallest pixel numbers. PMID:26158113

  13. Application of remote sensing image interpretation in seismic safety evaluation

    NASA Astrophysics Data System (ADS)

    Li, Feng; Wei, Wen-xia; Wang, Gang

    2005-10-01

    As one of essential design gist in important engineering projects, the seismic safety evaluation on choosing engineering site has been applied widely. Using remote sensing images, the analysis to regional seismotectonic environment can bring macroscopic, integrative, dynamic and high efficiency information, so the application of remote sensing technology in seismic safety evaluation of engineering site has fine prospect and will bring great benefit. In this paper, based on remote sensing interpretation to Landsat7 ETM images, also using GIS and field geological investigations, as a case study in Qingdao City, we analyze the physiognomy environment, new tectonic movement, faults activities, and the distributing of deleterious geological objects around the site. Then we find this method can provide good basic geological information for seismic safety evaluation.

  14. Physiological Imaging-Defined, Response-Driven Subvolumes of a Tumor

    SciTech Connect

    Farjam, Reza; Tsien, Christina I.; Feng, Felix Y.; Gomez-Hassan, Diana; Hayman, James A.; Lawrence, Theodore S.; Cao, Yue

    2013-04-01

    Purpose: To develop an image analysis framework to delineate the physiological imaging-defined subvolumes of a tumor in relating to treatment response and outcome. Methods and Materials: Our proposed approach delineates the subvolumes of a tumor based on its heterogeneous distributions of physiological imaging parameters. The method assigns each voxel a probabilistic membership function belonging to the physiological parameter classes defined in a sample of tumors, and then calculates the related subvolumes in each tumor. We applied our approach to regional cerebral blood volume (rCBV) and Gd-DTPA transfer constant (K{sup trans}) images of patients who had brain metastases and were treated by whole-brain radiation therapy (WBRT). A total of 45 lesions were included in the analysis. Changes in the rCBV (or K{sup trans})–defined subvolumes of the tumors from pre-RT to 2 weeks after the start of WBRT (2W) were evaluated for differentiation of responsive, stable, and progressive tumors using the Mann-Whitney U test. Performance of the newly developed metrics for predicting tumor response to WBRT was evaluated by receiver operating characteristic (ROC) curve analysis. Results: The percentage decrease in the high-CBV-defined subvolumes of the tumors from pre-RT to 2W was significantly greater in the group of responsive tumors than in the group of stable and progressive tumors (P<.007). The change in the high-CBV-defined subvolumes of the tumors from pre-RT to 2W was a predictor for post-RT response significantly better than change in the gross tumor volume observed during the same time interval (P=.012), suggesting that the physiological change occurs before the volumetric change. Also, K{sup trans} did not add significant discriminatory information for assessing response with respect to rCBV. Conclusion: The physiological imaging-defined subvolumes of the tumors delineated by our method could be candidates for boost target, for which further development and evaluation

  15. Design of Environmentally Responsive Fluorescent Polymer Probes for Cellular Imaging.

    PubMed

    Yamada, Arisa; Hiruta, Yuki; Wang, Jian; Ayano, Eri; Kanazawa, Hideko

    2015-08-10

    We report the development of environmentally responsive fluorescent polymers. The reversible temperature-induced phase transition of copolymers composed of N-isopropylacrylamide and a fluorescent monomer based on the fluorescein (FL), coumarin (CO), rhodamine (RH), or dansyl (DA) skeleton was used as a molecular switch to control the fluorescence intensity. The poly(N-isopropylacrylamide) (PNIPAAm) chain showed an expanded coil conformation below the lower critical solution temperature (LCST) due to hydration, but it changed to a globular form above the LCST due to dehydration. Through the combination of a polarity-sensitive fluorophore with PNIPAAm, the synthetic fluorescent polymer displayed a response to external temperature, with the fluorescence strength dramatically changing close to the LCST. Additionally, the P(NIPAAm-co-FL) and P(NIPAAm-co-CO) polymers, containing fluorescein and coumarin groups, respectively, exhibited pH responsiveness. The environmental responsiveness of the reported polymers is derived directly from the PNIPAAm and fluorophore structures, thus allowing for the cellular uptake of the fluorescence copolymer by RAW264.7 cells to be temperature-controlled. Cellular uptake was suppressed below the LCST but enhanced above the LCST. Furthermore, the cellular uptake of both P(NIPAAm-co-CO) and P(NIPAAm-co-RH) conjugated with a fusogenic lipid, namely, l-α-phosphatidylethanolamine, dioleoyl (DOPE), was enhanced. Such lipid-conjugated fluorescence probes are expected to be useful as physiological indicators for intracellular imaging. PMID:26121103

  16. Prediction of Early Response to Chemotherapy in Lung Cancer by Using Diffusion-Weighted MR Imaging

    PubMed Central

    Yu, Jing; Li, Weidong; Zhang, Zhang; Yu, Tielian; Li, Dong

    2014-01-01

    Purpose. To determine whether change of apparent diffusion coefficient (ADC) value could predict early response to chemotherapy in lung cancer. Materials and Methods. Twenty-five patients with advanced non-small cell lung cancer underwent chest MR imaging including DWI before and at the end of the first cycle of chemotherapy. The tumor's mean ADC value and diameters on MR images were calculated and compared. The grouping reference was based on serial CT scans according to Response Evaluation Criteria in Solid Tumors. Logistic regression was applied to assess treatment response prediction ability of ADC value and diameters. Results. The change of ADC value in partial response group was higher than that in stable disease group (P = 0.004). ROC curve showed that ADC value could predict treatment response with 100% sensitivity, 64.71% specificity, 57.14% positive predictive value, 100% negative predictive value, and 82.7% accuracy. The area under the curve for combination of ADC value and longest diameter change was higher than any parameter alone (P ≤ 0.01). Conclusions. The change of ADC value may be a sensitive indicator to predict early response to chemotherapy in lung cancer. Prediction ability could be improved by combining the change of ADC value and longest diameter. PMID:24688359

  17. Live Imaging of Drug Responses in the Tumor Microenvironment in Mouse Models of Breast Cancer

    PubMed Central

    Nakasone, Elizabeth S.; Askautrud, Hanne A.; Egeblad, Mikala

    2013-01-01

    The tumor microenvironment plays a pivotal role in tumor initiation, progression, metastasis, and the response to anti-cancer therapies. Three-dimensional co-culture systems are frequently used to explicate tumor-stroma interactions, including their role in drug responses. However, many of the interactions that occur in vivo in the intact microenvironment cannot be completely replicated in these in vitro settings. Thus, direct visualization of these processes in real-time has become an important tool in understanding tumor responses to therapies and identifying the interactions between cancer cells and the stroma that can influence these responses. Here we provide a method for using spinning disk confocal microscopy of live, anesthetized mice to directly observe drug distribution, cancer cell responses and changes in tumor-stroma interactions following administration of systemic therapy in breast cancer models. We describe procedures for labeling different tumor components, treatment of animals for observing therapeutic responses, and the surgical procedure for exposing tumor tissues for imaging up to 40 hours. The results obtained from this protocol are time-lapse movies, in which such processes as drug infiltration, cancer cell death and stromal cell migration can be evaluated using image analysis software. PMID:23542634

  18. Study of fish response using particle image velocimetry and high-speed, high-resolution imaging

    SciTech Connect

    Deng, Z.; Richmond, M. C.; Mueller, R. P.; Gruensch, G. R.

    2004-10-01

    Fish swimming has fascinated both engineers and fish biologists for decades. Digital particle image velocimetry (DPIV) and high-speed, high-resolution digital imaging are recently developed analysis tools that can help engineers and biologists better understand how fish respond to turbulent environments. This report details studies to evaluate DPIV. The studies included a review of existing literature on DPIV, preliminary studies to test the feasibility of using DPIV conducted at our Flow Biology Laboratory in Richland, Washington September through December 2003, and applications of high-speed, high-resolution digital imaging with advanced motion analysis to investigations of fish injury mechanisms in turbulent shear flows and bead trajectories in laboratory physical models. Several conclusions were drawn based on these studies, which are summarized as recommendations for proposed research at the end of this report.

  19. Detection of early plant stress responses in hyperspectral images

    NASA Astrophysics Data System (ADS)

    Behmann, Jan; Steinrücken, Jörg; Plümer, Lutz

    2014-07-01

    Early stress detection in crop plants is highly relevant, but hard to achieve. We hypothesize that close range hyperspectral imaging is able to uncover stress related processes non-destructively in the early stages which are invisible to the human eye. We propose an approach which combines unsupervised and supervised methods in order to identify several stages of progressive stress development from series of hyperspectral images. Stress of an entire plant is detected by stress response levels at pixel scale. The focus is on drought stress in barley (Hordeum vulgare). Unsupervised learning is used to separate hyperspectral signatures into clusters related to different stages of stress response and progressive senescence. Whereas all such signatures may be found in both, well watered and drought stressed plants, their respective distributions differ. Ordinal classification with Support Vector Machines (SVM) is used to quantify and visualize the distribution of progressive stages of senescence and to separate well watered from drought stressed plants. For each senescence stage a distinctive set of most relevant Vegetation Indices (VIs) is identified. The method has been applied on two experiments involving potted barley plants under well watered and drought stress conditions in a greenhouse. Drought stress is detected up to ten days earlier than using NDVI. Furthermore, it is shown that some VIs have overall relevance, while others are specific to particular senescence stages. The transferability of the method to the field is illustrated by an experiment on maize (Zea mays).

  20. Diagnostic imaging in the evaluation of leg pain in athletes.

    PubMed

    Bresler, Michael; Mar, Winnie; Toman, Jordan

    2012-04-01

    The causes of leg pain in the athlete are diverse. Pain can relate to more common etiologies, such as musculotendinous injury to the hamstrings and Achilles tendon as well as stress injury to bone, with tibial stress injuries comprising the most common cause for lower leg pain in athletes. Less-common causes include chronic exertional compartment syndrome and popliteal artery entrapment syndrome, both of which cause pain as a result of muscle ischemia. Radiologic evaluation plays an important role in differentiating among the many possible causes of leg pain and is often essential in determining degree of injury as well as in documenting healing before patient return to athletic activity. With PAES and hamstring and Achilles injuries, imaging may be helpful in surgical planning as well as in determining an underlying anatomic cause for injury. Several of these conditions can be evaluated with multiple different imaging modalities. The imaging modality of choice should be selected based on the sensitivity and specificity of the imaging examination but should also be tailored to each individual patient after determining comorbidities that may preclude certain types of imaging as well as assessing the patient's ability to undergo such testing. PMID:22341013

  1. Update on Magnetic Resonance Imaging and Ultrasound Evaluation of Crohn’s Disease

    PubMed Central

    Deepak, Parakkal; Kolbe, Amy B.; Fidler, Jeff L.; Fletcher, Joel G.; Knudsen, John M.

    2016-01-01

    Magnetic resonance enterography (MRE) and abdominal ultrasound are integral parts of multimodality assessments for patients with inflammatory bowel disease. Applications include assessing Crohn’s disease (CD) extent and severity, differentiating CD from ulcerative colitis, detecting CD complications, evaluating response to therapy, and demonstrating postoperative recurrence. Magnetic resonance imaging protocols are being developed that may reduce or eliminate the need for intravenous contrast agents and better differentiate inflammatory from fibrotic strictures. MRE scoring systems have been created to objectively quantify disease activity and response to therapy. By utilizing advanced sonographic imaging techniques, including ultrasound contrast and Doppler assessments, the role of abdominal ultrasonography in the evaluation and management of CD continues to expand. Abdominal ultrasound may function as a low-cost, point-of care assessment tool, especially in CD restricted to the terminal ileum and ileocolic anastomosis. PMID:27231453

  2. Update on Magnetic Resonance Imaging and Ultrasound Evaluation of Crohn's Disease.

    PubMed

    Deepak, Parakkal; Kolbe, Amy B; Fidler, Jeff L; Fletcher, Joel G; Knudsen, John M; Bruining, David H

    2016-04-01

    Magnetic resonance enterography (MRE) and abdominal ultrasound are integral parts of multimodality assessments for patients with inflammatory bowel disease. Applications include assessing Crohn's disease (CD) extent and severity, differentiating CD from ulcerative colitis, detecting CD complications, evaluating response to therapy, and demonstrating postoperative recurrence. Magnetic resonance imaging protocols are being developed that may reduce or eliminate the need for intravenous contrast agents and better differentiate inflammatory from fibrotic strictures. MRE scoring systems have been created to objectively quantify disease activity and response to therapy. By utilizing advanced sonographic imaging techniques, including ultrasound contrast and Doppler assessments, the role of abdominal ultrasonography in the evaluation and management of CD continues to expand. Abdominal ultrasound may function as a low-cost, point-of care assessment tool, especially in CD restricted to the terminal ileum and ileocolic anastomosis. PMID:27231453

  3. Pyramid wavefront sensor for image quality evaluation of optical system

    NASA Astrophysics Data System (ADS)

    Chen, Zhendong

    2015-08-01

    When the pyramid wavefront sensor is used to evaluate the imaging quality, placed at the focal plane of the aberrated optical system e.g., a telescope, it splits the light into four beams. Four images of the pupil are created on the detector and the detection signals of the pyramid wavefront sensor are calculated with these four intensity patterns, providing information on the derivatives of the aberrated wavefront. Based on the theory of the pyramid wavefront sensor, we are going to develop simulation software and a wavefront detector which can be used to test the imaging quality of the telescope. In our system, the subpupil image intensity through the pyramid sensor is calculated to obtain the aberration of wavefront where the piston, tilt, defocus, spherical, coma, astigmatism and other high level aberrations are separately represented by Zernike polynomials. The imaging quality of the optical system is then evaluated by the subsequent wavefront reconstruction. The performance of our system is to be checked by comparing with the measurements carried out using Puntino wavefront instrument (the method of SH wavefront sensor). Within this framework, the measurement precision of pyramid sensor will be discussed as well through detailed experiments. In general, this project would be very helpful both in our understanding of the principle of the wavefront reconstruction and its future technical applications. So far, we have produced the pyramid and established the laboratory setup of the image quality detecting system based on this wavefront sensor. Preliminary results are obtained, in that we have obtained the intensity images of the four pupils. Additional work is needed to analyze the characteristics of the pyramid wavefront sensor.

  4. Early Prediction and Evaluation of Breast Cancer Response to Neoadjuvant Chemotherapy Using Quantitative DCE-MRI.

    PubMed

    Tudorica, Alina; Oh, Karen Y; Chui, Stephen Y-C; Roy, Nicole; Troxell, Megan L; Naik, Arpana; Kemmer, Kathleen A; Chen, Yiyi; Holtorf, Megan L; Afzal, Aneela; Springer, Charles S; Li, Xin; Huang, Wei

    2016-02-01

    The purpose is to compare quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) metrics with imaging tumor size for early prediction of breast cancer response to neoadjuvant chemotherapy (NACT) and evaluation of residual cancer burden (RCB). Twenty-eight patients with 29 primary breast tumors underwent DCE-MRI exams before, after one cycle of, at midpoint of, and after NACT. MRI tumor size in the longest diameter (LD) was measured according to the RECIST (Response Evaluation Criteria In Solid Tumors) guidelines. Pharmacokinetic analyses of DCE-MRI data were performed with the standard Tofts and Shutter-Speed models (TM and SSM). After one NACT cycle the percent changes of DCE-MRI parameters K(trans) (contrast agent plasma/interstitium transfer rate constant), ve (extravascular and extracellular volume fraction), kep (intravasation rate constant), and SSM-unique τi (mean intracellular water lifetime) are good to excellent early predictors of pathologic complete response (pCR) vs. non-pCR, with univariate logistic regression C statistics value in the range of 0.804 to 0.967. ve values after one cycle and at NACT midpoint are also good predictors of response, with C ranging 0.845 to 0.897. However, RECIST LD changes are poor predictors with C = 0.609 and 0.673, respectively. Post-NACT K(trans), τi, and RECIST LD show statistically significant (P < .05) correlations with RCB. The performances of TM and SSM analyses for early prediction of response and RCB evaluation are comparable. In conclusion, quantitative DCE-MRI parameters are superior to imaging tumor size for early prediction of therapy response. Both TM and SSM analyses are effective for therapy response evaluation. However, the τi parameter derived only with SSM analysis allows the unique opportunity to potentially quantify therapy-induced changes in tumor energetic metabolism. PMID:26947876

  5. Computed tomography and magnetic resonance imaging evaluation of pericardial disease

    PubMed Central

    Shahid, Muhammad; Watkin, Richard W.

    2016-01-01

    Pericardial diseases are commonly encountered in clinical practice and may present as an isolated process or in association with various systemic conditions. Traditionally transthoracic echocardiography (TTE) has been the method of choice for the evaluation of suspected pericardial disease but increasingly computed tomography (CT) and magnetic resonance imaging (MRI) are also being used as part of a rational multi-modality imaging approach tailored to the specific clinical scenario. This paper reviews the role of CT and MRI across the spectrum of pericardial diseases. PMID:27429911

  6. Thermal parametric imaging in the evaluation of skin burn depth.

    PubMed

    Rumiński, Jacek; Kaczmarek, Mariusz; Renkielska, Alicja; Nowakowski, Antoni

    2007-02-01

    The aim of this paper is to determine the extent to which infrared (IR) thermal imaging may be used for skin burn depth evaluation. The analysis can be made on the basis of the development of a thermal model of the burned skin. Different methods such as the traditional clinical visual approach and the IR imaging modalities of static IR thermal imaging, active IR thermal imaging and active-dynamic IR thermal imaging (ADT) are analyzed from the point of view of skin burn depth diagnostics. In ADT, a new approach is proposed on the basis of parametric image synthesis. Calculation software is implemented for single-node and distributed systems. The properties of all the methods are verified in experiments using phantoms and subsequently in vivo with animals with a reference histopathological examination. The results indicate that it is possible to distinguish objectively and quantitatively burns which will heal spontaneously within three weeks of infliction and which should be treated conservatively from those which need surgery because they will not heal within this period. PMID:17278587

  7. Evaluation of image quality in computed radiography based mammography systems

    NASA Astrophysics Data System (ADS)

    Singh, Abhinav; Bhwaria, Vipin; Valentino, Daniel J.

    2011-03-01

    Mammography is the most widely accepted procedure for the early detection of breast cancer and Computed Radiography (CR) is a cost-effective technology for digital mammography. We have demonstrated that CR mammography image quality is viable for Digital Mammography. The image quality of mammograms acquired using Computed Radiography technology was evaluated using the Modulation Transfer Function (MTF), Noise Power Spectrum (NPS) and Detective Quantum Efficiency (DQE). The measurements were made using a 28 kVp beam (RQA M-II) using 2 mm of Al as a filter and a target/filter combination of Mo/Mo. The acquired image bit depth was 16 bits and the pixel pitch for scanning was 50 microns. A Step-Wedge phantom (to measure the Contrast-to-noise ratio (CNR)) and the CDMAM 3.4 Contrast Detail phantom were also used to assess the image quality. The CNR values were observed at varying thickness of PMMA. The CDMAM 3.4 phantom results were plotted and compared to the EUREF acceptable and achievable values. The effect on image quality was measured using the physics metrics. A lower DQE was observed even with a higher MTF. This could be possibly due to a higher noise component present due to the way the scanner was configured. The CDMAM phantom scores demonstrated a contrast-detail comparable to the EUREF values. A cost-effective CR machine was optimized for high-resolution and high-contrast imaging.

  8. Evaluation Responsibility and Leadership in the Face of Failing Democracies

    ERIC Educational Resources Information Center

    McKegg, Kate

    2013-01-01

    In a world faced with unprecedented rising levels of inequality and injustice, is there a responsibility for our evaluation organizations to take on a leadership role in promoting inclusive, evaluative dialog and deliberation about the state of our democracies in relation to key democratic principles and ideals? In this forum, I question whether…

  9. Evaluating the Chief School Administrator: Fulfilling the Board's Governance Responsibility.

    ERIC Educational Resources Information Center

    New Jersey School Boards Association, Trenton.

    Evaluating the chief school administrator's performance is one of the most important responsibilities of a board of education. In New Jersey, established guidelines for board evaluations of superintendents range from legal to procedural in the attempt to meet school district goals and objectives and to assess whether the superintendency fulfilled…

  10. Optoelectronic complex inner product for evaluating quality of image segmentation

    NASA Astrophysics Data System (ADS)

    Power, Gregory J.; Awwal, Abdul Ahad S.

    2000-11-01

    In automatic target recognition and machine vision applications, segmentation of the images is a key step. Poor segmentation reduces the recognition performance. For some imaging systems such as MRI and Synthetic Aperture Radar (SAR) it is difficult even for humans to agree on the location of the edge which allows for segmentation. A real- time dynamic approach to determine the quality of segmentation can enable vision systems to refocus of apply appropriate algorithms to ensure high quality segmentation for recognition. A recent approach to evaluate the quality of image segmentation uses percent-pixels-different (PPD). For some cases, PPD provides a reasonable quality evaluation, but it has a weakness in providing a measure for how well the shape of the segmentation matches the true shape. This paper introduces the complex inner product approach for providing a goodness measure for evaluating the segmentation quality based on shape. The complex inner product approach is demonstrated on SAR target chips obtained from the Moving and Stationary Target Acquisition and Recognition (MSTAR) program sponsored by the Defense Advanced Research Projects Agency (DARPA) and the Air Force Research Laboratory (AFRL). The results are compared to the PPD approach. A design for an optoelectronic implementation of the complex inner product for dynamic segmentation evaluation is introduced.

  11. Multimodal image coregistration and inducible selective cell ablation to evaluate imaging ligands

    PubMed Central

    Virostko, John; Henske, Joseph; Vinet, Laurent; Lamprianou, Smaragda; Dai, Chunhua; Radhika, Aramandla; Baldwin, Ronald M.; Ansari, Mohammad S.; Hefti, Franz; Skovronsky, Daniel; Kung, Hank F.; Herrera, Pedro L.; Peterson, Todd E.; Meda, Paolo; Powers, Alvin C.

    2011-01-01

    We combined multimodal imaging (bioluminescence, X-ray computed tomography, and PET), tomographic reconstruction of bioluminescent sources, and two unique, complementary models to evaluate three previously synthesized PET radiotracers thought to target pancreatic beta cells. The three radiotracers {[18F]fluoropropyl-(+)-dihydrotetrabenazine ([18F]FP-DTBZ), [18F](+)-2-oxiranyl-3-isobutyl-9-(3-fluoropropoxy)-10-methoxy-2,3,4,6,7,11b-hexahydro-1H-pyrido[2,1-a]isoquinoline (18F-AV-266), and (2S,3R,11bR)-9-(3-fluoropropoxy)-2-(hydroxymethyl)-3-isobutyl-10-methoxy-2,3,4,6,7,11b-hexahydro-1H-pyrido[2,1-a]isoquinolin-2-ol (18F-AV-300)} bind vesicular monoamine transporter 2. Tomographic reconstruction of the bioluminescent signal in mice expressing luciferase only in pancreatic beta cells was used to delineate the pancreas and was coregistered with PET and X-ray computed tomography images. This strategy enabled unambiguous identification of the pancreas on PET images, permitting accurate quantification of the pancreatic PET signal. We show here that, after conditional, specific, and rapid mouse beta-cell ablation, beta-cell loss was detected by bioluminescence imaging but not by PET imaging, given that the pancreatic signal provided by three PET radiotracers was not altered. To determine whether these ligands bound human beta cells in vivo, we imaged mice transplanted with luciferase-expressing human islets. The human islets were imaged by bioluminescence but not with the PET ligands, indicating that these vesicular monoamine transporter 2-directed ligands did not specifically bind beta cells. These data demonstrate the utility of coregistered multimodal imaging as a platform for evaluation and validation of candidate ligands for imaging islets. PMID:22143775

  12. Magnetic resonance imaging of rectal cancer: staging and restaging evaluation.

    PubMed

    Moreno, Courtney C; Sullivan, Patrick S; Kalb, Bobby T; Tipton, Russell G; Hanley, Krisztina Z; Kitajima, Hiroumi D; Dixon, W Thomas; Votaw, John R; Oshinski, John N; Mittal, Pardeep K

    2015-10-01

    Magnetic resonance imaging is used to non-invasively stage and restage rectal adenocarcinomas. Accurate staging is important as the depth of tumor extension and the presence or absence of lymph node metastases determines if an individual will undergo preoperative neoadjuvant chemoradiation. Accurate description of tumor location is important for presurgical planning. The relationship of the tumor to the anal sphincter in addition to the depth of local invasion determines the surgical approach used for resection. High-resolution T2-weighted imaging is the primary sequence used for initial staging. The addition of diffusion-weighted imaging improves accuracy in the assessment of treatment response on restaging scans. Approximately 10%-30% of individuals will experience a complete pathologic response following chemoradiation with no residual viable tumor found in the resected specimen at histopathologic assessment. In some centers, individuals with no residual tumor visible on restaging MR who are thought to be at high operative risk are monitored with serial imaging and a "watch and wait" approach in lieu of resection. Normal rectal anatomy, MR technique utilized for staging and restaging scans, and TMN staging are reviewed. An overview of surgical techniques used for resection including newer, minimally invasive endoluminal techniques is included. PMID:25759246

  13. Quantitative evaluation of image-based distortion correction in diffusion tensor imaging.

    PubMed

    Netsch, Thomas; van Muiswinkel, Arianne

    2004-07-01

    A statistical method for the evaluation of image registration for a series of images based on the assessment of consistency properties of the registration results is proposed. Consistency is defined as the residual error of the composition of cyclic registrations. By combining the transformations of different algorithms the consistency error allows a quantitative comparison without the use of ground truth, specifically, it allows a determination as to whether the algorithms are compatible and hence provide comparable registrations. Consistency testing is applied to evaluate retrospective correction of eddy current-induced image distortion in diffusion tensor imaging of the brain. In the literature several image transformations and similarity measures have been proposed, generally showing a significant reduction of distortion in side-by-side comparison of parametric maps before and after registration. Transformations derived from imaging physics and a three-dimensional affine transformation as well as mutual information (MI) and local correlation (LC) similarity are compared to each other by means of consistency testing. The dedicated transformations could not demonstrate a significant difference for more than half of the series considered. LC similarity is well-suited for distortion correction providing more consistent registrations which are comparable to MI. PMID:15250631

  14. Evaluation of Two Fractal Methods for Magnetogram Image Analysis

    NASA Technical Reports Server (NTRS)

    Stark, B.; Adams, M.; Hathaway, D. H.; Hagyard, M. J.

    1997-01-01

    Fractal and multifractal techniques have been applied to various types of solar data to study the fractal properties of sunspots as well as the distribution of photospheric magnetic fields and the role of random motions on the solar surface in this distribution. Other research includes the investigation of changes in the fractal dimension as an indicator for solar flares. Here we evaluate the efficacy of two methods for determining the fractal dimension of an image data set: the Differential Box Counting scheme and a new method, the Jaenisch scheme. To determine the sensitivity of the techniques to changes in image complexity, various types of constructed images are analyzed. In addition, we apply this method to solar magnetogram data from Marshall Space Flight Centers vector magnetograph.

  15. Evaluation of infrared collimators for testing thermal imaging systems

    NASA Astrophysics Data System (ADS)

    Chrzanowski, K.

    2007-06-01

    Infrared reflective collimators are important components of expensive sophisticated test systems used for testing thermal imagers. Too low quality collimators can become a source of significant measurement errors and collimators of too high quality can unnecessarily increase cost of a test system. In such a situation it is important for test system users to know proper requirements on the collimator and to be able to verify its performance. A method for evaluation of infrared reflective collimators used in test systems for testing thermal imagers is presented in this paper. The method requires only easily available optical equipment and can be used not only by collimator manufactures but also by users of test equipment to verify performance of the collimators used for testing thermal imagers.

  16. Dissociation of neuronal, electrodermal, and evaluative responses in disgust extinction.

    PubMed

    Klucken, Tim; Schweckendiek, Jan; Merz, Christian J; Vaitl, Dieter; Stark, Rudolf

    2013-06-01

    Disgust extinction is an important mechanism relevant for the treatment of psychiatric disorders. However, only a few studies have investigated disgust extinction. Moreover, because disgust sensitivity (DS) is considered as a relevant factor for learning processes, this study also investigated the potential relationship between DS and disgust extinction learning. The aim of this study was to explore the neuronal correlates of disgust extinction, as well as changes in skin conductance responses (SCRs) and evaluative conditioning. Twenty subjects were exposed to a differential extinction paradigm, in which a previous conditioned, and now unreinforced, stimulus (conditioned stimulus, CS+) was compared to a second stimulus (CS-), which was previously not associated with the unconditioned stimulus (UCS). Extinction learning was measured on three different response levels (BOLD responses, SCRs, and evaluative conditioning). Regarding evaluative conditioning, the CS+ was rated as more unpleasant than the CS-. Interestingly, significantly increased amygdala responses and SCRs toward to the CS- were observed. Finally, a (negative) trend was found between DS scores and BOLD responses of the prefrontal cortex. The present findings showed a dissociation of different response levels. The increased CS- responses could be explained by the assumption that the increased amygdala activity may reflect a safety learning signal during the first extinction trials and the subjective focus may therefore shift from the CS+ to the CS-. The correlation finding supports previous studies postulating that DS hampers extinction processes. The present results point toward dissociations between the response levels in context of extinction processes. PMID:23731074

  17. IMAGE ENHANCEMENT FOR IMPAIRED VISION: THE CHALLENGE OF EVALUATION

    PubMed Central

    PELI, ELI; WOODS, RUSSELL L

    2009-01-01

    With the aging of the population, the prevalence of eye diseases and thus of vision impairment is increasing. The TV watching habits of people with vision impairments are comparable to normally sighted people1, however their vision loss prevents them from fully benefiting from this medium. For over 20 years we have been developing video image-enhancement techniques designed to assist people with visual impairments, particularly those due to central retinal vision loss. A major difficulty in this endeavor is the lack of evaluation techniques to assess and compare the effectiveness of various enhancement methods. This paper reviews our approaches to image enhancement and the results we have obtained, with special emphasis on the difficulties encountered in the evaluation of the benefits of enhancement and the solutions we have developed to date. PMID:20161188

  18. Image-Based Evaluation of Vascular Function and Hemodynamics

    PubMed Central

    Lee, Jongmin

    2013-01-01

    The noticeable characteristics of the blood vascular structure are the inconsistent viscosity of blood and the stiffness of the vascular wall. If we can control these two factors, we can solve more problems related to hemodynamics and vascular wall function. Understanding the properties of hemodynamics and vascular wall function may provide more information applicable to clinical practice for cardiovascular disease. The bedside techniques evaluating vascular function usually measure indirect parameters. In contrast, some medical imaging techniques provide clear and direct depictions of functional cardiovascular characteristics. In this review, image-based evaluation of hemodynamic and vascular wall functions is discussed from the perspective of blood flow velocity, flow volume, flow pattern, peripheral vascular resistance, intraluminal pressure, vascular wall stress, and wall stiffness. PMID:26587430

  19. Supervised Evaluation of Image Segmentation and Object Proposal Techniques.

    PubMed

    Pont-Tuset, Jordi; Marques, Ferran

    2016-07-01

    This paper tackles the supervised evaluation of image segmentation and object proposal algorithms. It surveys, structures, and deduplicates the measures used to compare both segmentation results and object proposals with a ground truth database; and proposes a new measure: the precision-recall for objects and parts. To compare the quality of these measures, eight state-of-the-art object proposal techniques are analyzed and two quantitative meta-measures involving nine state of the art segmentation methods are presented. The meta-measures consist in assuming some plausible hypotheses about the results and assessing how well each measure reflects these hypotheses. As a conclusion of the performed experiments, this paper proposes the tandem of precision-recall curves for boundaries and for objects-and-parts as the tool of choice for the supervised evaluation of image segmentation. We make the datasets and code of all the measures publicly available. PMID:26415155

  20. Task-specific evaluation of 3D image interpolation techniques

    NASA Astrophysics Data System (ADS)

    Grevera, George J.; Udupa, Jayaram K.; Miki, Yukio

    1998-06-01

    Image interpolation is an important operation that is widely used in medical imaging, image processing, and computer graphics. A variety of interpolation methods are available in the literature. However, their systematic evaluation is lacking. At a previous meeting, we presented a framework for the task independent comparison of interpolation methods based on a variety of medical image data pertaining to different parts of the human body taken from different modalities. In this new work, we present an objective, task-specific framework for evaluating interpolation techniques. The task considered is how the interpolation methods influence the accuracy of quantification of the total volume of lesions in the brain of Multiple Sclerosis (MS) patients. Sixty lesion detection experiments coming from ten patient studies, two subsampling techniques and the original data, and 3 interpolation methods is presented along with a statistical analysis of the results. This work comprises a systematic framework for the task-specific comparison of interpolation methods. Specifically, the influence of three interpolation methods in MS lesion quantification is compared.

  1. NIR hyperspectral imaging to evaluate degradation in captopril commercial tablets.

    PubMed

    França, Leandro de Moura; Pimentel, Maria Fernanda; Simões, Simone da Silva; Grangeiro, Severino; Prats-Montalbán, José M; Ferrer, Alberto

    2016-07-01

    Pharmaceutical quality control is important for improving the effectiveness, purity and safety of drugs, as well as for the prevention or control of drug degradation. In the present work, near infrared hyperspectral images (HSI-NIR) of tablets with different expiration dates were employed to evaluate the degradation of captopril into captopril disulfide in different layers, on the top and on the bottom surfaces of the tablets. Multivariate curve resolution (MCR) models were used to extract the concentration distribution maps from the hyperspectral images. Afterward, multivariate image techniques were applied to the concentration distribution maps (CDMs), to extract features and build models relating the main characteristics of the images to their corresponding manufacturing dates. Resolution methods followed by extracting features were able to estimate the tablet manufacture date with a prediction error of 120days. The model developed could be useful to evaluate whether a sample shows a degradation pattern consistent with the date of manufacturing or to detect abnormal behaviors in the natural degradation process of the sample. The information provided by the HIS-NIR is important for the development of the process (QbD), looking inside the formulation, revealing the behavior of the active pharmaceutical ingredient (API) during the product's shelf life. PMID:27163244

  2. PET Parametric Response Mapping for Clinical Monitoring and Treatment Response Evaluation in Brain Tumors.

    PubMed

    Ellingson, Benjamin M; Chen, Wei; Harris, Robert J; Pope, Whitney B; Lai, Albert; Nghiemphu, Phioanh L; Czernin, Johannes; Phelps, Michael E; Cloughesy, Timothy F

    2013-04-01

    PET parametric response maps (PRMs) are a provocative new molecular imaging technique for quantifying brain tumor response to therapy in individual patients. By aligning sequential PET scans over time using anatomic MR imaging information, the voxel-wise change in radiotracer uptake can be quantified and visualized. PET PRMs can be performed before and after a particular therapy to test whether the tumor is responding favorably, or performed relative to a distant time point to monitor changes through the course of a treatment. This article focuses on many of the technical details involved in generating, visualizing, and quantifying PET PRMs, and practical applications and example case studies. PMID:27157948

  3. Simulation of brain tumors in MR images for evaluation of segmentation efficacy.

    PubMed

    Prastawa, Marcel; Bullitt, Elizabeth; Gerig, Guido

    2009-04-01

    Obtaining validation data and comparison metrics for segmentation of magnetic resonance images (MRI) are difficult tasks due to the lack of reliable ground truth. This problem is even more evident for images presenting pathology, which can both alter tissue appearance through infiltration and cause geometric distortions. Systems for generating synthetic images with user-defined degradation by noise and intensity inhomogeneity offer the possibility for testing and comparison of segmentation methods. Such systems do not yet offer simulation of sufficiently realistic looking pathology. This paper presents a system that combines physical and statistical modeling to generate synthetic multi-modal 3D brain MRI with tumor and edema, along with the underlying anatomical ground truth, Main emphasis is placed on simulation of the major effects known for tumor MRI, such as contrast enhancement, local distortion of healthy tissue, infiltrating edema adjacent to tumors, destruction and deformation of fiber tracts, and multi-modal MRI contrast of healthy tissue and pathology. The new method synthesizes pathology in multi-modal MRI and diffusion tensor imaging (DTI) by simulating mass effect, warping and destruction of white matter fibers, and infiltration of brain tissues by tumor cells. We generate synthetic contrast enhanced MR images by simulating the accumulation of contrast agent within the brain. The appearance of the the brain tissue and tumor in MRI is simulated by synthesizing texture images from real MR images. The proposed method is able to generate synthetic ground truth and synthesized MR images with tumor and edema that exhibit comparable segmentation challenges to real tumor MRI. Such image data sets will find use in segmentation reliability studies, comparison and validation of different segmentation methods, training and teaching, or even in evaluating standards for tumor size like the RECIST criteria (response evaluation criteria in solid tumors). PMID:19119055

  4. Evaluation of tissue optical properties from light distribution images

    NASA Astrophysics Data System (ADS)

    Tsai, Cheng-Lun; Chang, Ming; Hsieh, Jui-Hsiang; Yang, Yi-Fong; Chou, Yi-Sheong

    2000-06-01

    Images of light distribution in biological soft tissue we used to study the optical characteristics of tissue. The light distribution image was taken under a microscope with light injected through a pinhole close to the edge of the top surface. Images taken on skin, fat, and muscle tissues were compared to study the effect of cellular structure and temperature on the light intensity distribution. Monte Carlo simulation with the same conditions was also performed to simulate the light intensity distribution in tissue for comparison. The anisotropy scattering of light in tissue is affected by the tissue microscopic structure, such as the direction of muscle tissue fibers. The change in optical properties of fat and muscle tissue with temperature was observed. The two-dimensional light distribution images offer more information than general reflectance and transmission measurements. By matching the simulated light intensity distribution with the light distribution image, the optical properties of biological tissue could be estimated. This method might be applied in tissue engineering as an economic way for evaluating the microscopic structure of tissue.

  5. Diagnosing, planning and evaluating osteochondral ankle defects with imaging modalities.

    PubMed

    van Bergen, Christiaan Ja; Gerards, Rogier M; Opdam, Kim Tm; Terra, Maaike P; Kerkhoffs, Gino Mmj

    2015-12-18

    This current concepts review outlines the role of different imaging modalities in the diagnosis, preoperative planning, and follow-up of osteochondral ankle defects. An osteochondral ankle defect involves the articular cartilage and subchondral bone (usually of the talus) and is mostly caused by an ankle supination trauma. Conventional radiographs are useful as an initial imaging tool in the diagnostic process, but have only moderate sensitivity for the detection of osteochondral defects. Computed tomography (CT) and magnetic resonance imaging (MRI) are more accurate imaging modalities. Recently, ultrasonography and single photon emission CT have been described for the evaluation of osteochondral talar defects. CT is the most valuable modality for assessing the exact location and size of bony lesions. Cartilage and subchondral bone damage can be visualized using MRI, but the defect size tends to be overestimated due to bone edema. CT with the ankle in full plantar flexion has been shown a reliable tool for preoperative planning of the surgical approach. Postoperative imaging is useful for objective assessment of repair tissue or degenerative changes of the ankle joint. Plain radiography, CT and MRI have been used in outcome studies, and different scoring systems are available. PMID:26716090

  6. Early-phase myocardial infarction: Evaluation by MR imaging

    SciTech Connect

    Tscholakoff, D.; Higgins, C.B.; McNamara, M.T.; Derugin, N.

    1986-06-01

    In vivo gated magnetic resonance (MR) imaging was performed in 12 dogs immediately after occlusion of the left anterior descending coronary artery and serially up to 5 hours and again between 4 and 14 days. This was done to evaluate the appearance of acute myocardial infarcts and to determine how soon after coronary artery occlusion MR imaging can demonstrate the site of acute myocardial ischemia. In nine dogs with postmortem evidence of myocardial infarction, regional increase of signal intensity of the myocardium was present by 3 hours after coronary occlusion and conformed to the site of myocardial infarct found at autopsy. The signal intensity on T2-weighted images of the infarcted on T2-weighted images of the infarcted myocardium was significantly greater than that of normal myocardium at 3, 4, and 5 hours after occlusion. The T2 (spin-spin) relaxation time was significantly prolonged in the region of myocardial infarct at 3, 4, and 5 hours post-occlusion compared with normal myocardium. Myocardial wall thinning and increased intracavitary flow signal were found in six dogs with comparable pre- and postocclusion images in late systole.

  7. Automatic Evaluation of Welded Joints Using Image Processing on Radiographs

    NASA Astrophysics Data System (ADS)

    Schwartz, Ch.

    2003-03-01

    Radiography is frequently used to detect discontinuities in welded joints (porosity, cracks, lack of penetration). Perfect knowledge of the geometry of these defects is an important step which is essential to appreciate the quality of the weld. Because of this, an action improving the interpretation of radiographs by image processing has been undertaken. The principle consists in making a radiograph of the welded joint and of a depth step wedge penetrameter in the material. The radiograph is then finely digitized and an automatic processing of the radiograph of the penetrameter image allows the establishment of a correspondence between grey levels and material thickness. An algorithm based on image processing is used to localize defects in the welded joints and to isolate them from the original image. First, defects detected by this method are characterized in terms of dimension and equivalent thickness. Then, from the image of the healthy welded joint (that is to say without the detected defects), characteristic values of the weld are evaluated (thickness reduction, width).

  8. Diagnosing, planning and evaluating osteochondral ankle defects with imaging modalities

    PubMed Central

    van Bergen, Christiaan JA; Gerards, Rogier M; Opdam, Kim TM; Terra, Maaike P; Kerkhoffs, Gino MMJ

    2015-01-01

    This current concepts review outlines the role of different imaging modalities in the diagnosis, preoperative planning, and follow-up of osteochondral ankle defects. An osteochondral ankle defect involves the articular cartilage and subchondral bone (usually of the talus) and is mostly caused by an ankle supination trauma. Conventional radiographs are useful as an initial imaging tool in the diagnostic process, but have only moderate sensitivity for the detection of osteochondral defects. Computed tomography (CT) and magnetic resonance imaging (MRI) are more accurate imaging modalities. Recently, ultrasonography and single photon emission CT have been described for the evaluation of osteochondral talar defects. CT is the most valuable modality for assessing the exact location and size of bony lesions. Cartilage and subchondral bone damage can be visualized using MRI, but the defect size tends to be overestimated due to bone edema. CT with the ankle in full plantar flexion has been shown a reliable tool for preoperative planning of the surgical approach. Postoperative imaging is useful for objective assessment of repair tissue or degenerative changes of the ankle joint. Plain radiography, CT and MRI have been used in outcome studies, and different scoring systems are available. PMID:26716090

  9. Evaluation of various speckle reduction filters on medical ultrasound images.

    PubMed

    Wu, Shibin; Zhu, Qingsong; Xie, Yaoqin

    2013-01-01

    At present, ultrasound is one of the essential tools for noninvasive medical diagnosis. However, speckle noise is inherent in medical ultrasound images and it is the cause for decreased resolution and contrast-to-noise ratio. Low image quality is an obstacle for effective feature extraction, recognition, analysis, and edge detection; it also affects image interpretation by doctor and the accuracy of computer-assisted diagnostic techniques. Thus, speckle reduction is significant and critical step in pre-processing of ultrasound images. Many speckle reduction techniques have been studied by researchers, but to date there is no comprehensive method that takes all the constraints into consideration. In this paper we discuss seven filters, namely Lee, Frost, Median, Speckle Reduction Anisotropic Diffusion (SRAD), Perona-Malik's Anisotropic Diffusion (PMAD) filter, Speckle Reduction Bilateral Filter (SRBF) and Speckle Reduction filter based on soft thresholding in the Wavelet transform. A comparative study of these filters has been made in terms of preserving the features and edges as well as effectiveness of de-noising.We computed five established evaluation metrics in order to determine which despeckling algorithm is most effective and optimal for real-time implementation. In addition, the experimental results have been demonstrated by filtered images and statistical data table. PMID:24109896

  10. Radiometric Quality Evaluation of INSAT-3D Imager Data

    NASA Astrophysics Data System (ADS)

    Prakash, S.; Jindal, D.; Badal, N.; Kartikeyan, B.; Gopala Krishna, B.

    2014-11-01

    INSAT-3D is an advanced meteorological satellite of ISRO which acquires imagery in optical and infra-red (IR) channels for study of weather dynamics in Indian sub-continent region. In this paper, methodology of radiometric quality evaluation for Level-1 products of Imager, one of the payloads onboard INSAT-3D, is described. Firstly, overall visual quality of scene in terms of dynamic range, edge sharpness or modulation transfer function (MTF), presence of striping and other image artefacts is computed. Uniform targets in Desert and Sea region are identified for which detailed radiometric performance evaluation for IR channels is carried out. Mean brightness temperature (BT) of targets is computed and validated with independently generated radiometric references. Further, diurnal/seasonal trends in target BT values and radiometric uncertainty or sensor noise are studied. Results of radiometric quality evaluation over duration of eight months (January to August 2014) and comparison of radiometric consistency pre/post yaw flip of satellite are presented. Radiometric Analysis indicates that INSAT-3D images have high contrast (MTF > 0.2) and low striping effects. A bias of <4K is observed in the brightness temperature values of TIR-1 channel measured during January-August 2014 indicating consistent radiometric calibration. Diurnal and seasonal analysis shows that Noise equivalent differential temperature (NEdT) for IR channels is consistent and well within specifications.

  11. Retinal oxygen saturation evaluation by multi-spectral fundus imaging

    NASA Astrophysics Data System (ADS)

    Khoobehi, Bahram; Ning, Jinfeng; Puissegur, Elise; Bordeaux, Kimberly; Balasubramanian, Madhusudhanan; Beach, James

    2007-03-01

    Purpose: To develop a multi-spectral method to measure oxygen saturation of the retina in the human eye. Methods: Five Cynomolgus monkeys with normal eyes were anesthetized with intramuscular ketamine/xylazine and intravenous pentobarbital. Multi-spectral fundus imaging was performed in five monkeys with a commercial fundus camera equipped with a liquid crystal tuned filter in the illumination light path and a 16-bit digital camera. Recording parameters were controlled with software written specifically for the application. Seven images at successively longer oxygen-sensing wavelengths were recorded within 4 seconds. Individual images for each wavelength were captured in less than 100 msec of flash illumination. Slightly misaligned images of separate wavelengths due to slight eye motion were registered and corrected by translational and rotational image registration prior to analysis. Numerical values of relative oxygen saturation of retinal arteries and veins and the underlying tissue in between the artery/vein pairs were evaluated by an algorithm previously described, but which is now corrected for blood volume from averaged pixels (n > 1000). Color saturation maps were constructed by applying the algorithm at each image pixel using a Matlab script. Results: Both the numerical values of relative oxygen saturation and the saturation maps correspond to the physiological condition, that is, in a normal retina, the artery is more saturated than the tissue and the tissue is more saturated than the vein. With the multi-spectral fundus camera and proper registration of the multi-wavelength images, we were able to determine oxygen saturation in the primate retinal structures on a tolerable time scale which is applicable to human subjects. Conclusions: Seven wavelength multi-spectral imagery can be used to measure oxygen saturation in retinal artery, vein, and tissue (microcirculation). This technique is safe and can be used to monitor oxygen uptake in humans. This work

  12. Tissue response to mechanical vibrations for "sonoelasticity imaging".

    PubMed

    Parker, K J; Huang, S R; Musulin, R A; Lerner, R M

    1990-01-01

    The goal of "sonoelasticity imaging" is to differentiate between normal soft tissues and hard lesions. This is done by measuring and then displaying the ultrasound Doppler spectrum of regions within tissues which are mechanically forced with low frequency (20-1000 Hz) vibrations. The resolution and sensitivity of the technique ultimately rest on the spatial resolution of ultrasound Doppler detection, the low frequency mechanical properties of tissues, and the vibration response of layered, inhomogeneous regions with hard tumor inclusions and complicated boundary conditions set by the presence of skin, bones and other regions. An initial investigation has measured some tissue stiffness parameters, and applied these in a NASTRAN finite element analysis to simulate a prostate tumor in the pelvic cavity. The measurements show a wide separation between the elastic modulus of tumors and soft tissues such as muscle and prostate. NASTRAN analyses show the ability to delineate regions of different elasticity based on the pattern of vibration amplitudes. The ability to change vibration frequency within the 100-300 Hz band seems particularly helpful in simulations and experiments which visualize small stiff inclusions in tissues. Preliminary results support the postulate that sonoelasticity imaging can provide useful information concerning tissue properties that are not otherwise obtainable. PMID:2194336

  13. Binge drinking, depression, and electrocortical responses to emotional images.

    PubMed

    Connell, Arin M; Patton, Emily; McKillop, Hannah

    2015-09-01

    Binge drinking and depression are highly prevalent, associated with cognitive and affective impairments, and frequently co-occur. Yet little research has examined their joint relations with such processing impairment. The current study examines the relation between symptoms of depression, binge drinking, and the magnitude of early (early posterior negativity, EPN) and later (P3 and late positive potential, LPP) visual processing components of affectively negative, positive, and neutral visual stimuli. Participants included 42 undergraduate students recruited on the basis of depressive symptoms. Results of repeated measures analyses of variance (ANOVAs; Depression × Binge × Emotion × Laterality) showed that binge drinkers exhibited lower LPP amplitudes for negative images, compared with nonbinge drinkers, regardless of depression, consistent with motivational models of alcohol abuse. Otherwise, differences across depressed and nondepressed groups were largest among binge drinkers, including a pattern of stronger early attentional engagement (EPN) to negative and neutral images, but decreased later processing (P3 and LPP) across all emotional categories, consistent with a vigilance-avoidance response pattern. PMID:25915691

  14. Noise evaluation of Compton camera imaging for proton therapy.

    PubMed

    Ortega, P G; Torres-Espallardo, I; Cerutti, F; Ferrari, A; Gillam, J E; Lacasta, C; Llosá, G; Oliver, J F; Sala, P R; Solevi, P; Rafecas, M

    2015-03-01

    Compton Cameras emerged as an alternative for real-time dose monitoring techniques for Particle Therapy (PT), based on the detection of prompt-gammas. As a consequence of the Compton scattering process, the gamma origin point can be restricted onto the surface of a cone (Compton cone). Through image reconstruction techniques, the distribution of the gamma emitters can be estimated, using cone-surfaces backprojections of the Compton cones through the image space, along with more sophisticated statistical methods to improve the image quality. To calculate the Compton cone required for image reconstruction, either two interactions, the last being photoelectric absorption, or three scatter interactions are needed. Because of the high energy of the photons in PT the first option might not be adequate, as the photon is not absorbed in general. However, the second option is less efficient. That is the reason to resort to spectral reconstructions, where the incoming γ energy is considered as a variable in the reconstruction inverse problem. Jointly with prompt gamma, secondary neutrons and scattered photons, not strongly correlated with the dose map, can also reach the imaging detector and produce false events. These events deteriorate the image quality. Also, high intensity beams can produce particle accumulation in the camera, which lead to an increase of random coincidences, meaning events which gather measurements from different incoming particles. The noise scenario is expected to be different if double or triple events are used, and consequently, the reconstructed images can be affected differently by spurious data. The aim of the present work is to study the effect of false events in the reconstructed image, evaluating their impact in the determination of the beam particle ranges. A simulation study that includes misidentified events (neutrons and random coincidences) in the final image of a Compton Telescope for PT monitoring is presented. The complete chain of

  15. Noise evaluation of Compton camera imaging for proton therapy

    NASA Astrophysics Data System (ADS)

    Ortega, P. G.; Torres-Espallardo, I.; Cerutti, F.; Ferrari, A.; Gillam, J. E.; Lacasta, C.; Llosá, G.; Oliver, J. F.; Sala, P. R.; Solevi, P.; Rafecas, M.

    2015-02-01

    Compton Cameras emerged as an alternative for real-time dose monitoring techniques for Particle Therapy (PT), based on the detection of prompt-gammas. As a consequence of the Compton scattering process, the gamma origin point can be restricted onto the surface of a cone (Compton cone). Through image reconstruction techniques, the distribution of the gamma emitters can be estimated, using cone-surfaces backprojections of the Compton cones through the image space, along with more sophisticated statistical methods to improve the image quality. To calculate the Compton cone required for image reconstruction, either two interactions, the last being photoelectric absorption, or three scatter interactions are needed. Because of the high energy of the photons in PT the first option might not be adequate, as the photon is not absorbed in general. However, the second option is less efficient. That is the reason to resort to spectral reconstructions, where the incoming γ energy is considered as a variable in the reconstruction inverse problem. Jointly with prompt gamma, secondary neutrons and scattered photons, not strongly correlated with the dose map, can also reach the imaging detector and produce false events. These events deteriorate the image quality. Also, high intensity beams can produce particle accumulation in the camera, which lead to an increase of random coincidences, meaning events which gather measurements from different incoming particles. The noise scenario is expected to be different if double or triple events are used, and consequently, the reconstructed images can be affected differently by spurious data. The aim of the present work is to study the effect of false events in the reconstructed image, evaluating their impact in the determination of the beam particle ranges. A simulation study that includes misidentified events (neutrons and random coincidences) in the final image of a Compton Telescope for PT monitoring is presented. The complete chain of

  16. Evaluation of a large format image tube camera for the shuttle sortie mission

    NASA Technical Reports Server (NTRS)

    Tifft, W. C.

    1976-01-01

    A large format image tube camera of a type under consideration for use on the Space Shuttle Sortie Missions is evaluated. The evaluation covers the following subjects: (1) resolving power of the system (2) geometrical characteristics of the system (distortion etc.) (3) shear characteristics of the fiber optic coupling (4) background effects in the tube (5) uniformity of response of the tube (as a function of wavelength) (6) detective quantum efficiency of the system (7) astronomical applications of the system. It must be noted that many of these characteristics are quantitatively unique to the particular tube under discussion and serve primarily to suggest what is possible with this type of tube.

  17. Molecular Imaging Probes for Diagnosis and Therapy Evaluation of Breast Cancer

    PubMed Central

    Meng, Qingqing; Li, Zheng

    2013-01-01

    Breast cancer is a major cause of cancer death in women where early detection and accurate assessment of therapy response can improve clinical outcomes. Molecular imaging, which includes PET, SPECT, MRI, and optical modalities, provides noninvasive means of detecting biological processes and molecular events in vivo. Molecular imaging has the potential to enhance our understanding of breast cancer biology and effects of drug action during both preclinical and clinical phases of drug development. This has led to the identification of many molecular imaging probes for key processes in breast cancer. Hormone receptors, growth factor receptor, and angiogenic factors, such as ER, PR, HER2, and VEGFR, have been adopted as imaging targets to detect and stage the breast cancer and to monitor the treatment efficacy. Receptor imaging probes are usually composed of targeting moiety attached to a signaling component such as a radionuclide that can be detected using dedicated instruments. Current molecular imaging probes involved in breast cancer diagnosis and therapy evaluation are reviewed, and future of molecular imaging for the preclinical and clinical is explained. PMID:23533377

  18. Malignant gliomas: current perspectives in diagnosis, treatment, and early response assessment using advanced quantitative imaging methods

    PubMed Central

    Ahmed, Rafay; Oborski, Matthew J; Hwang, Misun; Lieberman, Frank S; Mountz, James M

    2014-01-01

    Malignant gliomas consist of glioblastomas, anaplastic astrocytomas, anaplastic oligodendrogliomas and anaplastic oligoastrocytomas, and some less common tumors such as anaplastic ependymomas and anaplastic gangliogliomas. Malignant gliomas have high morbidity and mortality. Even with optimal treatment, median survival is only 12–15 months for glioblastomas and 2–5 years for anaplastic gliomas. However, recent advances in imaging and quantitative analysis of image data have led to earlier diagnosis of tumors and tumor response to therapy, providing oncologists with a greater time window for therapy management. In addition, improved understanding of tumor biology, genetics, and resistance mechanisms has enhanced surgical techniques, chemotherapy methods, and radiotherapy administration. After proper diagnosis and institution of appropriate therapy, there is now a vital need for quantitative methods that can sensitively detect malignant glioma response to therapy at early follow-up times, when changes in management of nonresponders can have its greatest effect. Currently, response is largely evaluated by measuring magnetic resonance contrast and size change, but this approach does not take into account the key biologic steps that precede tumor size reduction. Molecular imaging is ideally suited to measuring early response by quantifying cellular metabolism, proliferation, and apoptosis, activities altered early in treatment. We expect that successful integration of quantitative imaging biomarker assessment into the early phase of clinical trials could provide a novel approach for testing new therapies, and importantly, for facilitating patient management, sparing patients from weeks or months of toxicity and ineffective treatment. This review will present an overview of epidemiology, molecular pathogenesis and current advances in diagnoses, and management of malignant gliomas. PMID:24711712

  19. Preclinical evaluation of a novel cyanine dye for tumor imaging with in vivo photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Temma, Takashi; Onoe, Satoru; Kanazaki, Kengo; Ono, Masahiro; Saji, Hideo

    2014-09-01

    Photoacoustic imaging (PA imaging or PAI) has shown great promise in the detection and monitoring of cancer. Although nanocarrier-based contrast agents have been studied for use in PAI, small molecule contrast agents are required due to their ease of preparation, cost-effectiveness, and low toxicity. Here, we evaluated the usefulness of a novel cyanine dye IC7-1-Bu as a PAI contrast agent without conjugated targeting moieties for in vivo tumor imaging in a mice model. Basic PA characteristics of IC7-1-Bu were compared with indocyanine green (ICG), a Food and Drug Administration approved dye, in an aqueous solution. We evaluated the tumor accumulation profile of IC7-1-Bu and ICG by in vivo fluorescence imaging. In vivo PAI was then performed with a photoacoustic tomography system 24 and 48 h after intravenous injection of IC7-1-Bu into tumor bearing mice. IC7-1-Bu showed about a 2.3-fold higher PA signal in aqueous solution compared with that of ICG. Unlike ICG, IC7-1-Bu showed high tumor fluorescence after intravenous injection. In vivo PAI provided a tumor to background PA signal ratio of approximately 2.5 after intravenous injection of IC7-1-Bu. These results indicate that IC7-1-Bu is a promising PAI contrast agent for cancer imaging without conjugation of targeting moieties.

  20. New performance evaluation models for character detection in images

    NASA Astrophysics Data System (ADS)

    Wang, YanWei; Ding, XiaoQing; Liu, ChangSong; Wang, Kongqiao

    2010-02-01

    Detection of characters regions is a meaningful research work for both highlighting region of interest and recognition for further information processing. A lot of researches have been performed on character localization and extraction and this leads to the great needs of performance evaluation scheme to inspect detection algorithms. In this paper, two probability models are established to accomplish evaluation tasks for different applications respectively. For highlighting region of interest, a Gaussian probability model, which simulates the property of a low-pass Gaussian filter of human vision system (HVS), was constructed to allocate different weights to different character parts. It reveals the greatest potential to describe the performance of detectors, especially, when the result detected is an incomplete character, where other methods cannot effectively work. For the recognition destination, we also introduced a weighted probability model to give an appropriate description for the contribution of detection results to final recognition results. The validity of performance evaluation models proposed in this paper are proved by experiments on web images and natural scene images. These models proposed in this paper may also be able to be applied in evaluating algorithms of locating other objects, like face detection and more wide experiments need to be done to examine the assumption.

  1. A hyperspectral imaging prototype for online quality evaluation of pickling cucumbers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A hyperspectral imaging prototype was developed for online evaluation of external and internal quality of pickling cucumbers. The prototype had several new, unique features including simultaneous reflectance and transmittance imaging and inline, real time calibration of hyperspectral images of each ...

  2. Incidental Findings in Imaging Research: Evaluating Incidence, Benefit and Burden

    PubMed Central

    Orme, Nicholas M.; Fletcher, Joel G.; Siddiki, Hassan A.; Harmsen, W. Scott; O’Byrne, Megan M.; Port, John D.; Tremaine, William J.; Pitot, Henry C.; McFarland, Beth; Robinson, Marguerite E.; Koenig, Barabara A.; King, Bernard F.; Wolf, Susan M.

    2013-01-01

    Context Little information exists concerning the frequency of clinically significant incidental findings (IFs) identified in the course of imaging research across a broad spectrum of imaging modalities and body regions. Objective To estimate the frequency with which research imaging IFs generate further clinical action, and the medical benefit/burden of identifying these IFs. Design, Setting, and Participants Retrospective review of subjects undergoing a research imaging exam that was interpreted by a radiologist for IFs in the first quarter of 2004, with 3-year clinical follow-up. An expert panel reviewed IFs generating clinical action to determine medical benefit/burden based on predefined criteria. Main Outcome Measures Frequency of (1) IFs that generated further clinical action by modality, body part, age, gender, and (2) IFs resulting in clear medical benefit or burden. Results 1376 patients underwent 1426 research imaging studies. 40% (567/1426) of exams had at least one IF (1055 total). Risk of an IF increased significantly by age (OR=1.5; [1.4–1.7=95% C.I.] per decade increase). Abdominopelvic CT generated more IFs than other exams (OR=18.9 compared with ultrasound; 9.2% with subsequent clinical action), with CT Thorax and MR brain next (OR=11.9 and 5.9; 2.8% and 2.2% with action, respectively). Overall 6.2% of exams (35/567) with an IF generated clinical action, resulting in clear medical benefit in 1.1% (6/567) and clear medical burden in 0.5% (3/567). In most instances, medical benefit/burden was unclear (4.6%; 26/567). Conclusions The frequency of IFs in imaging research exams varies significantly by imaging modality, body region and age. Research imaging studies at high risk for generating IFs can be identified. Routine evaluation of research images by radiologists may result in identification of IFs in a substantial number of cases and subsequent clinical action to address them in much smaller number. Such clinical action can result in medical

  3. Recognizing plankton images from the shadow image particle profiling evaluation recorder.

    PubMed

    Luo, Tong; Kramer, Kurt; Goldgof, Dmitry B; Hall, Lawrence O; Samson, Scott; Remsen, Andrew; Hopkins, Thomas

    2004-08-01

    We present a system to recognize underwater plankton images from the shadow image particle profiling evaluation recorder (SIPPER). The challenge of the SIPPER image set is that many images do not have clear contours. To address that, shape features that do not heavily depend on contour information were developed. A soft margin support vector machine (SVM) was used as the classifier. We developed a way to assign probability after multiclass SVM classification. Our approach achieved approximately 90% accuracy on a collection of plankton images. On another larger image set containing manually unidentifiable particles, it also provided 75.6% overall accuracy. The proposed approach was statistically significantly more accurate on the two data sets than a C4.5 decision tree and a cascade correlation neural network. The single SVM significantly outperformed ensembles of decision trees created by bagging and random forests on the smaller data set and was slightly better on the other data set. The 15-feature subset produced by our feature selection approach provided slightly better accuracy than using all 29 features. Our probability model gave us a reasonable rejection curve on the larger data set. PMID:15462442

  4. Validation of tablet-based evaluation of color fundus images

    PubMed Central

    Christopher, Mark; Moga, Daniela C.; Russell, Stephen R.; Folk, James C.; Scheetz, Todd; Abràmoff, Michael D.

    2012-01-01

    Purpose To compare diabetic retinopathy (DR) referral recommendations made by viewing fundus images using a tablet computer to recommendations made using a standard desktop display. Methods A tablet computer (iPad) and a desktop PC with a high-definition color display were compared. For each platform, two retinal specialists independently rated 1200 color fundus images from patients at risk for DR using an annotation program, Truthseeker. The specialists determined whether each image had referable DR, and also how urgently each patient should be referred for medical examination. Graders viewed and rated the randomly presented images independently and were masked to their ratings on the alternative platform. Tablet- and desktop display-based referral ratings were compared using cross-platform, intra-observer kappa as the primary outcome measure. Additionally, inter-observer kappa, sensitivity, specificity, and area under ROC (AUC) were determined. Results A high level of cross-platform, intra-observer agreement was found for the DR referral ratings between the platforms (κ=0.778), and for the two graders, (κ=0.812). Inter-observer agreement was similar for the two platforms (κ=0.544 and κ=0.625 for tablet and desktop, respectively). The tablet-based ratings achieved a sensitivity of 0.848, a specificity of 0.987, and an AUC of 0.950 compared to desktop display-based ratings. Conclusions In this pilot study, tablet-based rating of color fundus images for subjects at risk for DR was consistent with desktop display-based rating. These results indicate that tablet computers can be reliably used for clinical evaluation of fundus images for DR. PMID:22495326

  5. Evaluation of scatter effects on image quality for breast tomosynthesis

    SciTech Connect

    Wu Gang; Mainprize, James G.; Boone, John M.; Yaffe, Martin J.

    2009-10-15

    Digital breast tomosynthesis uses a limited number (typically 10-20) of low-dose x-ray projections to produce a pseudo-three-dimensional volume tomographic reconstruction of the breast. The purpose of this investigation was to characterize and evaluate the effect of scattered radiation on the image quality for breast tomosynthesis. In a simulation, scatter point spread functions generated by a Monte Carlo simulation method were convolved over the breast projection to estimate the distribution of scatter for each angle of tomosynthesis projection. The results demonstrate that in the absence of scatter reduction techniques, images will be affected by cupping artifacts, and there will be reduced accuracy of attenuation values inferred from the reconstructed images. The effect of x-ray scatter on the contrast, noise, and lesion signal-difference-to-noise ratio (SDNR) in tomosynthesis reconstruction was measured as a function of the tumor size. When a with-scatter reconstruction was compared to one without scatter for a 5 cm compressed breast, the following results were observed. The contrast in the reconstructed central slice image of a tumorlike mass (14 mm in diameter) was reduced by 30%, the voxel value (inferred attenuation coefficient) was reduced by 28%, and the SDNR fell by 60%. The authors have quantified the degree to which scatter degrades the image quality over a wide range of parameters relevant to breast tomosynthesis, including x-ray beam energy, breast thickness, breast diameter, and breast composition. They also demonstrate, though, that even without a scatter rejection device, the contrast and SDNR in the reconstructed tomosynthesis slice are higher than those of conventional mammographic projection images acquired with a grid at an equivalent total exposure.

  6. Evaluation of the Emergency Response Dose Assessment System(ERDAS)

    NASA Technical Reports Server (NTRS)

    Evans, Randolph J.; Lambert, Winifred C.; Manobianco, John T.; Taylor, Gregory E.; Wheeler, Mark M.; Yersavich, Ann M.

    1996-01-01

    The emergency response dose assessment system (ERDAS) is a protype software and hardware system configured to produce routine mesoscale meteorological forecasts and enhanced dispersion estimates on an operational basis for the Kennedy Space Center (KSC)/Cape Canaveral Air Station (CCAS) region. ERDAS provides emergency response guidance to operations at KSC/CCAS in the case of an accidental hazardous material release or an aborted vehicle launch. This report describes the evaluation of ERDAS including: evaluation of sea breeze predictions, comparison of launch plume location and concentration predictions, case study of a toxic release, evaluation of model sensitivity to varying input parameters, evaluation of the user interface, assessment of ERDA's operational capabilities, and a comparison of ERDAS models to the ocean breeze dry gultch diffusion model.

  7. An evaluation of Compton scatter imaging using COMSCAN

    NASA Astrophysics Data System (ADS)

    Finlayson, R. D.; Ramsbottom, W.; Sturrock, W. R.

    1993-05-01

    A number of test samples, representative of aircraft materials and structures, were evaluated using a commercial x-ray backscatter radiation device called COMSCAN, developed by Philips. COMSCAN produces 22 simultaneous radiographic slices of a test object with only one-sided access. The slices, stored in computer memory, can then be paged through one at a time for viewing. The system has been integrated with a six-axis gantry robot system. During the COMSCAN evaluation, a number of test samples of graphite/epoxy, honeycomb, aluminum, and other low atomic number materials found on today's aircraft were scanned to determine the detectability of a variety of manufactured discontinuities including water in honeycomb, disbonds, delaminations, and corrosion. COMSCAN's ability to image a volume of 100 mm by 50 mm by 10 mm depth was very useful and allowed image display and analysis in both two and three dimensions. The collected images clearly show COMSCAN is well suited for detection of voids and defects where loss of material has occurred, such as corrosion pitting. COMSCAN, however, cannot detect delaminations.

  8. Evaluating an image-fusion algorithm with synthetic-image-generation tools

    NASA Astrophysics Data System (ADS)

    Gross, Harry N.; Schott, John R.

    1996-06-01

    An algorithm that combines spectral mixing and nonlinear optimization is used to fuse multiresolution images. Image fusion merges images of different spatial and spectral resolutions to create a high spatial resolution multispectral combination. High spectral resolution allows identification of materials in the scene, while high spatial resolution locates those materials. In this algorithm, conventional spectral mixing estimates the percentage of each material (called endmembers) within each low resolution pixel. Three spectral mixing models are compared; unconstrained, partially constrained, and fully constrained. In the partially constrained application, the endmember fractions are required to sum to one. In the fully constrained application, all fractions are additionally required to lie between zero and one. While negative fractions seem inappropriate, they can arise from random spectral realizations of the materials. In the second part of the algorithm, the low resolution fractions are used as inputs to a constrained nonlinear optimization that calculates the endmember fractions for the high resolution pixels. The constraints mirror the low resolution constraints and maintain consistency with the low resolution fraction results. The algorithm can use one or more higher resolution sharpening images to locate the endmembers to high spatial accuracy. The algorithm was evaluated with synthetic image generation (SIG) tools. A SIG developed image can be used to control the various error sources that are likely to impair the algorithm performance. These error sources include atmospheric effects, mismodeled spectral endmembers, and variability in topography and illumination. By controlling the introduction of these errors, the robustness of the algorithm can be studied and improved upon. The motivation for this research is to take advantage of the next generation of multi/hyperspectral sensors. Although the hyperspectral images will be of modest to low resolution

  9. Evaluation of muscle injury using magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    LeBlanc, A. D.; Jaweed, M.; Evans, H.

    1993-01-01

    The objective of this study was to investigate spin echo T2 relaxation time changes in thigh muscles after intense eccentric exercise in healthy men. Spin echo and calculated T2 relaxation time images of the thighs were obtained on several occasions after exercise of one limb; the contralateral limb served as control. Muscle damage was verified by elevated levels of serum creatine kinase (CK). Thirty percent of the time no exercise effect was discernible on the magnetic resonance (MR) images. In all positive MR images (70%) the semitendinosus muscle was positive, while the biceps femoris, short head, and gracilis muscles were also positive in 50% and 25% of the total cases, respectively. The peak T2 relaxation time and serum CK were correlated (r = 0.94, p<0.01); temporal changes in muscle T2 relaxation time and serum CK were similar, although T2 relaxation time remained positive after serum CK returned to background levels. We conclude that magnetic resonance imaging can serve as a useful tool in the evaluation of eccentric exercise muscle damage by providing a quantitative indicator of damage and its resolution as well as the specific areas and muscles.

  10. Evaluation schemes for video and image anomaly detection algorithms

    NASA Astrophysics Data System (ADS)

    Parameswaran, Shibin; Harguess, Josh; Barngrover, Christopher; Shafer, Scott; Reese, Michael

    2016-05-01

    Video anomaly detection is a critical research area in computer vision. It is a natural first step before applying object recognition algorithms. There are many algorithms that detect anomalies (outliers) in videos and images that have been introduced in recent years. However, these algorithms behave and perform differently based on differences in domains and tasks to which they are subjected. In order to better understand the strengths and weaknesses of outlier algorithms and their applicability in a particular domain/task of interest, it is important to measure and quantify their performance using appropriate evaluation metrics. There are many evaluation metrics that have been used in the literature such as precision curves, precision-recall curves, and receiver operating characteristic (ROC) curves. In order to construct these different metrics, it is also important to choose an appropriate evaluation scheme that decides when a proposed detection is considered a true or a false detection. Choosing the right evaluation metric and the right scheme is very critical since the choice can introduce positive or negative bias in the measuring criterion and may favor (or work against) a particular algorithm or task. In this paper, we review evaluation metrics and popular evaluation schemes that are used to measure the performance of anomaly detection algorithms on videos and imagery with one or more anomalies. We analyze the biases introduced by these by measuring the performance of an existing anomaly detection algorithm.

  11. Lymphoma of the mediastinum and neck: Evaluation with Ga-67 imaging and CT correlation

    SciTech Connect

    Drossman, S.R.; Schiff, R.G.; Kronfeld, G.D.; McNamara, J.; Leonidas, J.C. )

    1990-01-01

    The role of gallium-67 in the differentiation between active disease and fibrotic changes in patients with childhood lymphoma involving the mediastinum and neck was evaluated prospectively. Ga-67 imaging and computed tomography (CT) were correlated with clinical findings at the time of initial presentation and follow-up in 19 patients. Both modalities enabled detection of active disease on all occasions, but CT results were false-positive for residual disease in 10 patients (53%), whereas Ga-67 imaging results were false-positive in only one patient (5%). Neither modality, however, proved accurate in patients with rebound thymic hyperplasia. Ga-67 imaging is a useful tool for assessing response to therapy in children with lymphoma of the mediastinum and neck.

  12. Evaluating the capability of time-of-flight cameras for accurately imaging a cyclically loaded beam

    NASA Astrophysics Data System (ADS)

    Lahamy, Hervé; Lichti, Derek; El-Badry, Mamdouh; Qi, Xiaojuan; Detchev, Ivan; Steward, Jeremy; Moravvej, Mohammad

    2015-05-01

    Time-of-flight cameras are used for diverse applications ranging from human-machine interfaces and gaming to robotics and earth topography. This paper aims at evaluating the capability of the Mesa Imaging SR4000 and the Microsoft Kinect 2.0 time-of-flight cameras for accurately imaging the top surface of a concrete beam subjected to fatigue loading in laboratory conditions. Whereas previous work has demonstrated the success of such sensors for measuring the response at point locations, the aim here is to measure the entire beam surface in support of the overall objective of evaluating the effectiveness of concrete beam reinforcement with steel fibre reinforced polymer sheets. After applying corrections for lens distortions to the data and differencing images over time to remove systematic errors due to internal scattering, the periodic deflections experienced by the beam have been estimated for the entire top surface of the beam and at witness plates attached. The results have been assessed by comparison with measurements from highly-accurate laser displacement transducers. This study concludes that both the Microsoft Kinect 2.0 and the Mesa Imaging SR4000s are capable of sensing a moving surface with sub-millimeter accuracy once the image distortions have been modeled and removed.

  13. Noise evaluation of early images for Landsat 8 Operational Land Imager.

    PubMed

    Ren, Huazhong; Du, Chen; Liu, Rongyuan; Qin, Qiming; Yan, Guangjian; Li, Zhao-Liang; Meng, Jinjie

    2014-11-01

    This study performed an on-orbit evaluation of noise level for the Operational Land Imager (OLI) onboard Landsat 8 using early images over ground homogeneous sites. The signal-to-noise ratios (SNR) were higher than 160 of OLI nine bands at typical radiance level, while the noise equivalent radiance difference (NE∆L) and the noise equivalent reflectance difference (NE∆ρ) were respectively lower than 0.8 W/m(2)/µm/sr and 0.002. Compared to pre-launch predictions, the on-orbit low noise and high SNR almost satisfied requirements for OLI bands, and can provide a prior knowledge for uncertainty analysis of OLI images in monitoring land surface, oceanic, and atmospheric status. PMID:25401877

  14. Protection performance evaluation regarding imaging sensors hardened against laser dazzling

    NASA Astrophysics Data System (ADS)

    Ritt, Gunnar; Körber, Michael; Forster, Daniel; Eberle, Bernd

    2014-10-01

    Electro-optical imaging sensors are widely distributed and used for many different tasks in military operations and civil security. However, their operational capability can be easily disturbed by laser radiation. The likeliness of such an incidence has dramatically increased in the past years due to the free availability of high-power laser pointers. These laser systems, offering laser powers of several watts, pose an increased risk to the human eye as well as to electro-optical sensors. An adequate protection of electro-optical sensors against dazzling is highly desirable. Such protection can be accomplished with different technologies; however, none of the existing technologies can provide a sufficient protection. All current protection measures possess individual advantages and disadvantages. We present the results on the performance of two different protection technologies. The evaluation is based on automatic optical pattern recognition of sensor images taken from a scene containing triangles.

  15. Quantitative Evaluation of Strain Near Tooth Fillet by Image Processing

    NASA Astrophysics Data System (ADS)

    Masuyama, Tomoya; Yoshiizumi, Satoshi; Inoue, Katsumi

    The accurate measurement of strain and stress in a tooth is important for the reliable evaluation of the strength or life of gears. In this research, a strain measurement method which is based on image processing is applied to the analysis of strain near the tooth fillet. The loaded tooth is photographed using a CCD camera and stored as a digital image. The displacement of the point in the tooth flank is tracked by the cross-correlation method, and then, the strain is calculated. The interrogation window size of the correlation method and the overlap amount affect the accuracy and resolution. In the case of measurements at structures with complicated profiles such as fillets, the interrogation window maintains a large size and the overlap amount should be large. The surface condition also affects the accuracy. The white painted surface with a small black particle is suitable for measurement.

  16. Developing oxygen-enhanced magnetic resonance imaging as a prognostic biomarker of radiation response.

    PubMed

    White, Derek A; Zhang, Zhang; Li, Li; Gerberich, Jeni; Stojadinovic, Strahinja; Peschke, Peter; Mason, Ralph P

    2016-09-28

    Oxygen-Enhanced Magnetic Resonance Imaging (OE-MRI) techniques were evaluated as potential non-invasive predictive biomarkers of radiation response. Semi quantitative blood-oxygen level dependent (BOLD) and tissue oxygen level dependent (TOLD) contrast, and quantitative responses of relaxation rates (ΔR1 and ΔR2*) to an oxygen breathing challenge during hypofractionated radiotherapy were applied. OE-MRI was performed on subcutaneous Dunning R3327-AT1 rat prostate tumors (n=25) at 4.7 T prior to each irradiation (2F × 15 Gy) to the gross tumor volume. Response to radiation, while inhaling air or oxygen, was assessed by tumor growth delay measured up to four times the initial irradiated tumor volume (VQT). Radiation-induced hypoxia changes were confirmed using a double hypoxia marker assay. Inhaling oxygen during hypofractionated radiotherapy significantly improved radiation response. A correlation was observed between the difference in the 2nd and 1st ΔR1 (ΔΔR1) and VQT for air breathing rats. The TOLD response before the 2nd fraction showed a moderate correlation with VQT for oxygen breathing rats. The correlations indicate useful prognostic factors to predict tumor response to hypofractionation and could readily be applied for patient stratification and personalized radiotherapy treatment planning. PMID:27267808

  17. CMOS Image Sensor and System for Imaging Hemodynamic Changes in Response to Deep Brain Stimulation.

    PubMed

    Zhang, Xiao; Noor, Muhammad S; McCracken, Clinton B; Kiss, Zelma H T; Yadid-Pecht, Orly; Murari, Kartikeya

    2016-06-01

    Deep brain stimulation (DBS) is a therapeutic intervention used for a variety of neurological and psychiatric disorders, but its mechanism of action is not well understood. It is known that DBS modulates neural activity which changes metabolic demands and thus the cerebral circulation state. However, it is unclear whether there are correlations between electrophysiological, hemodynamic and behavioral changes and whether they have any implications for clinical benefits. In order to investigate these questions, we present a miniaturized system for spectroscopic imaging of brain hemodynamics. The system consists of a 144 ×144, [Formula: see text] pixel pitch, high-sensitivity, analog-output CMOS imager fabricated in a standard 0.35 μm CMOS process, along with a miniaturized imaging system comprising illumination, focusing, analog-to-digital conversion and μSD card based data storage. This enables stand alone operation without a computer, nor electrical or fiberoptic tethers. To achieve high sensitivity, the pixel uses a capacitive transimpedance amplifier (CTIA). The nMOS transistors are in the pixel while pMOS transistors are column-parallel, resulting in a fill factor (FF) of 26%. Running at 60 fps and exposed to 470 nm light, the CMOS imager has a minimum detectable intensity of 2.3 nW/cm(2) , a maximum signal-to-noise ratio (SNR) of 49 dB at 2.45 μW/cm(2) leading to a dynamic range (DR) of 61 dB while consuming 167 μA from a 3.3 V supply. In anesthetized rats, the system was able to detect temporal, spatial and spectral hemodynamic changes in response to DBS. PMID:26357405

  18. [Image quality evaluation of new image reconstruction methods applying the iterative reconstruction].

    PubMed

    Takata, Tadanori; Ichikawa, Katsuhiro; Hayashi, Hiroyuki; Mitsui, Wataru; Sakuta, Keita; Koshida, Haruka; Yokoi, Tomohiro; Matsubara, Kousuke; Horii, Jyunsei; Iida, Hiroji

    2012-01-01

    The purpose of this study was to evaluate the image quality of an iterative reconstruction method, the iterative reconstruction in image space (IRIS), which was implemented in a 128-slices multi-detector computed tomography system (MDCT), Siemens Somatom Definition Flash (Definition). We evaluated image noise by standard deviation (SD) as many researchers did before, and in addition, we measured modulation transfer function (MTF), noise power spectrum (NPS), and perceptual low-contrast detectability using a water phantom including a low-contrast object with a 10 Hounsfield unit (HU) contrast, to evaluate whether the noise reduction of IRIS was effective. The SD and NPS were measured from the images of a water phantom. The MTF was measured from images of a thin metal wire and a bar pattern phantom with the bar contrast of 125 HU. The NPS of IRIS was lower than that of filtered back projection (FBP) at middle and high frequency regions. The SD values were reduced by 21%. The MTF of IRIS and FBP measured by the wire phantom coincided precisely. However, for the bar pattern phantom, the MTF values of IRIS at 0.625 and 0.833 cycle/mm were lower than those of FBP. Despite the reduction of the SD and the NPS, the low-contrast detectability study indicated no significant difference between IRIS and FBP. From these results, it was demonstrated that IRIS had the noise reduction performance with exact preservation for high contrast resolution and slight degradation of middle contrast resolution, and could slightly improve the low contrast detectability but with no significance. PMID:22516592

  19. A comparison of five standard methods for evaluating image intensity uniformity in partially parallel imaging MRI

    PubMed Central

    Goerner, Frank L.; Duong, Timothy; Stafford, R. Jason; Clarke, Geoffrey D.

    2013-01-01

    Purpose: To investigate the utility of five different standard measurement methods for determining image uniformity for partially parallel imaging (PPI) acquisitions in terms of consistency across a variety of pulse sequences and reconstruction strategies. Methods: Images were produced with a phantom using a 12-channel head matrix coil in a 3T MRI system (TIM TRIO, Siemens Medical Solutions, Erlangen, Germany). Images produced using echo-planar, fast spin echo, gradient echo, and balanced steady state free precession pulse sequences were evaluated. Two different PPI reconstruction methods were investigated, generalized autocalibrating partially parallel acquisition algorithm (GRAPPA) and modified sensitivity-encoding (mSENSE) with acceleration factors (R) of 2, 3, and 4. Additionally images were acquired with conventional, two-dimensional Fourier imaging methods (R = 1). Five measurement methods of uniformity, recommended by the American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA) were considered. The methods investigated were (1) an ACR method and a (2) NEMA method for calculating the peak deviation nonuniformity, (3) a modification of a NEMA method used to produce a gray scale uniformity map, (4) determining the normalized absolute average deviation uniformity, and (5) a NEMA method that focused on 17 areas of the image to measure uniformity. Changes in uniformity as a function of reconstruction method at the same R-value were also investigated. Two-way analysis of variance (ANOVA) was used to determine whether R-value or reconstruction method had a greater influence on signal intensity uniformity measurements for partially parallel MRI. Results: Two of the methods studied had consistently negative slopes when signal intensity uniformity was plotted against R-value. The results obtained comparing mSENSE against GRAPPA found no consistent difference between GRAPPA and mSENSE with regard to signal intensity uniformity

  20. Evaluation of the Compressive Response of Notched Composite Panels using a Full-Field Displacement Measurement System

    NASA Technical Reports Server (NTRS)

    McGowan, David M.; Ambur, Damodar R.; Hanna, T. Glen; McNeill, Stephen R.

    1999-01-01

    An experimental and analytical evaluation of the compressive response of two composite, notched stiffened panels representative of primary composite wing structure is presented. A three-dimensional full-field image correlation technique is used to measure all three displacement components over global and local areas of the test panels. Point-wise and full-field results obtained using the image correlation technique are presented and compared to experimental results and analytical results obtained using nonlinear finite element analysis. Both global and global-local image correlation results are presented and discussed. Results of a simple calibration test of this image correlation technique are also presented.

  1. Evaluation of automated brain MR image segmentation and volumetry methods.

    PubMed

    Klauschen, Frederick; Goldman, Aaron; Barra, Vincent; Meyer-Lindenberg, Andreas; Lundervold, Arvid

    2009-04-01

    We compare three widely used brain volumetry methods available in the software packages FSL, SPM5, and FreeSurfer and evaluate their performance using simulated and real MR brain data sets. We analyze the accuracy of gray and white matter volume measurements and their robustness against changes of image quality using the BrainWeb MRI database. These images are based on "gold-standard" reference brain templates. This allows us to assess between- (same data set, different method) and also within-segmenter (same method, variation of image quality) comparability, for both of which we find pronounced variations in segmentation results for gray and white matter volumes. The calculated volumes deviate up to >10% from the reference values for gray and white matter depending on method and image quality. Sensitivity is best for SPM5, volumetric accuracy for gray and white matter was similar in SPM5 and FSL and better than in FreeSurfer. FSL showed the highest stability for white (<5%), FreeSurfer (6.2%) for gray matter for constant image quality BrainWeb data. Between-segmenter comparisons show discrepancies of up to >20% for the simulated data and 24% on average for the real data sets, whereas within-method performance analysis uncovered volume differences of up to >15%. Since the discrepancies between results reach the same order of magnitude as volume changes observed in disease, these effects limit the usability of the segmentation methods for following volume changes in individual patients over time and should be taken into account during the planning and analysis of brain volume studies. PMID:18537111

  2. Ultrasound Evaluation of Dynamic Responses of Female Pelvic Floor Muscles

    PubMed Central

    Peng, Qiyu; Jones, Ruth; Shishido, Keiichi; Constantinou, Christos E.

    2007-01-01

    Ultrasound imaging of the pelvic floor carrys diagnostically important information about the dynamic response of the Pelvic Floor Muscles (PFM) to potentially incontinence-producing stress, which can not be readily captured and assimilated by the observer during the scanning process. We presented an approach based on motion tracking to quantatively analyze the dynamic parameters of PFM on the Ano-Rectal Angle (ARA). Perineal ultrasonography was performed on 22 asymptomatic females and 9 Stress Urinary Incontinent (SUI) patients with a broad age distribution and parity. The ventral-dorsal and cephalad-caudad movements of the ARA were resolved and kinematic parameters, in terms of displacement, trajectory, velocity and acceleration were analyzed. The results revealed the possible mechanisms of PFM responses to prevent the urine from incontinence in fast and stress events. The statistical analyses showed the PFM responses of the healthy subjects and the SUI patients are significantly different in both the supine and standing experiments. PMID:17210220

  3. Evaluation of the FWL Responsive Headstart Program 1970-1972.

    ERIC Educational Resources Information Center

    Miller, Stephen

    This evaluation report of the Far West Laboratory Responsive Head Start Program, an inservice training program for preschool educators, discusses the effectiveness of the Laboratory's program and gives specific recommendations for improving it. The present report contains data that continue to support earlier findings indicating that the…

  4. 40 CFR 265.93 - Preparation, evaluation, and response.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... additional ground-water samples from those downgradient wells where a significant difference was detected..., STORAGE, AND DISPOSAL FACILITIES Ground-Water Monitoring § 265.93 Preparation, evaluation, and response... an outline of a ground-water quality assessment program. The outline must describe a...

  5. 40 CFR 265.93 - Preparation, evaluation, and response.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... additional ground-water samples from those downgradient wells where a significant difference was detected..., STORAGE, AND DISPOSAL FACILITIES Ground-Water Monitoring § 265.93 Preparation, evaluation, and response... an outline of a ground-water quality assessment program. The outline must describe a...

  6. 40 CFR 265.93 - Preparation, evaluation, and response.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... additional ground-water samples from those downgradient wells where a significant difference was detected..., STORAGE, AND DISPOSAL FACILITIES Ground-Water Monitoring § 265.93 Preparation, evaluation, and response... an outline of a ground-water quality assessment program. The outline must describe a...

  7. 40 CFR 265.93 - Preparation, evaluation, and response.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... additional ground-water samples from those downgradient wells where a significant difference was detected..., STORAGE, AND DISPOSAL FACILITIES Ground-Water Monitoring § 265.93 Preparation, evaluation, and response... an outline of a ground-water quality assessment program. The outline must describe a...

  8. Evaluating Item Fit for Multidimensional Item Response Models

    ERIC Educational Resources Information Center

    Zhang, Bo; Stone, Clement A.

    2008-01-01

    This research examines the utility of the s-x[superscript 2] statistic proposed by Orlando and Thissen (2000) in evaluating item fit for multidimensional item response models. Monte Carlo simulation was conducted to investigate both the Type I error and statistical power of this fit statistic in analyzing two kinds of multidimensional test…

  9. An Evaluation of Response Prompts for Teaching Behavior Chains

    ERIC Educational Resources Information Center

    Seaver, Jessica L.; Bourret, Jason C.

    2014-01-01

    Individuals who have been diagnosed with autism spectrum disorders can have difficulty acquiring new skills, and teaching procedures found to be efficient with 1 individual may not be efficient with others. However, relatively little research has evaluated methods to identify efficient, individualized response-prompt and prompt-fading procedures.…

  10. Evaluating the Response of the Terrestrial Biosphere to Significant Drought

    NASA Astrophysics Data System (ADS)

    Shiach, I.; Baker, I. T.; Denning, A.

    2011-12-01

    The response of terrestrial fluxes of energy, water, and carbon to drought is evaluated. Major droughts should be clearly evident in reanalyzed precipitation data, although this is not always the case. With reduced precipitation we can expect a suppression in Gross Primary Photosynthesis (GPP) if physiological stress is sufficient, with atttendant changes in energy partitioning due to stomatal closure. There may also be a response in respiratory release of CO2 with temperature increase. This study aimed to investigate the behavior of the terrestrial biosphere using the Simple Biosphere Model (SiB3) during and following times of drought and to identify any model responses inconsistent with observational relationships. The Standardized Precipitation Index (SPI) was evaluated from 1983 to 2006 in order to evaluate historical drought maps, and to facilitate a qualitative analysis of modeled drought behavior. Standardized and raw anomaly maps were produced for modeled physiological variables (GPP, transpiration, respiration, heat fluxes, carbon flux, and stress factors) in order to determine general response patterns for comparison with observations. The SiB model was determined to be generally accurate in its representation of significant drought, with regard to perturbations in Bowen ratio, GPP, and CO2 respiration. However, model response was heterogeneous, and did not always respond in a manner consistent with published descriptions of drought.

  11. Experimental/clinical evaluation of EIT image reconstruction with l1 data and image norms

    NASA Astrophysics Data System (ADS)

    Mamatjan, Yasin; Borsic, Andrea; Gürsoy, Doga; Adler, Andy

    2013-04-01

    Electrical impedance tomography (EIT) image reconstruction is ill-posed, and the spatial resolution of reconstructed images is low due to the diffuse propagation of current and limited number of independent measurements. Generally, image reconstruction is formulated using a regularized scheme in which l2 norms are preferred for both the data misfit and image prior terms due to computational convenience which result in smooth solutions. However, recent work on a Primal Dual-Interior Point Method (PDIPM) framework showed its effectiveness in dealing with the minimization problem. l1 norms on data and regularization terms in EIT image reconstruction address both problems of reconstruction with sharp edges and dealing with measurement errors. We aim for a clinical and experimental evaluation of the PDIPM method by selecting scenarios (human lung and dog breathing) with known electrode errors, which require a rigorous regularization and cause the failure of reconstructions with l2 norm. Results demonstrate the applicability of PDIPM algorithms, especially l1 data and regularization norms for clinical applications of EIT showing that l1 solution is not only more robust to measurement errors in clinical setting, but also provides high contrast resolution on organ boundaries.

  12. Evaluation of image placement of EPL stencil masks

    NASA Astrophysics Data System (ADS)

    Yusa, Satoshi; Ishikawa, Mikio; Kinase, Yoshinori; Takikawa, Tadahiko; Fujita, Hiroshi; Sano, Hisatake; Houga, Morihisa; Hayashi, Naoya

    2004-08-01

    200-mm stencil masks for electron beam projection lithography (EPL) have been developed. Since they are not so rigid as photomasks because of their structure, 200-mm wafers with about 8,000 membrane windows, new metrological techniques dedicated to stencil masks have be introduced. Image placement (IP) accuracy of an EPL mask is evaluated with a suspension-type electrostatic chuck introduced to a Leica LMS IPRO. The dynamic repeatability of global IP measurements was 27 nm (3σ). It was confirmed that global IP errors were reduced to 60 nm (3σ, max) by linear-term and gravity corrections.

  13. Evaluation of Fiber Reinforced Cement Using Digital Image Correlation

    PubMed Central

    Melenka, Garrett W.; Carey, Jason P.

    2015-01-01

    The effect of short fiber reinforcements on the mechanical properties of cement has been examined using a splitting tensile – digital image correlation (DIC) measurement method. Three short fiber reinforcement materials have been used in this study: fiberglass, nylon, and polypropylene. The method outlined provides a simple experimental setup that can be used to evaluate the ultimate tensile strength of brittle materials as well as measure the full field strain across the surface of the splitting tensile test cylindrical specimen. Since the DIC measurement technique is a contact free measurement this method can be used to assess sample failure. PMID:26039590

  14. Evaluation of fiber reinforced cement using digital image correlation.

    PubMed

    Melenka, Garrett W; Carey, Jason P

    2015-01-01

    The effect of short fiber reinforcements on the mechanical properties of cement has been examined using a splitting tensile - digital image correlation (DIC) measurement method. Three short fiber reinforcement materials have been used in this study: fiberglass, nylon, and polypropylene. The method outlined provides a simple experimental setup that can be used to evaluate the ultimate tensile strength of brittle materials as well as measure the full field strain across the surface of the splitting tensile test cylindrical specimen. Since the DIC measurement technique is a contact free measurement this method can be used to assess sample failure. PMID:26039590

  15. Dynamic contrast-enhanced magnetic resonance imaging for prediction of response to neoadjuvant chemotherapy in breast cancer

    NASA Astrophysics Data System (ADS)

    Fu, Juzhong; Fan, Ming; Zheng, Bin; Shao, Guoliang; Zhang, Juan; Li, Lihua

    2016-03-01

    Breast cancer is the second leading cause of women death in the United States. Currently, Neoadjuvant Chemotherapy (NAC) has become standard treatment paradigms for breast cancer patients. Therefore, it is important to find a reliable non-invasive assessment and prediction method which can evaluate and predict the response of NAC on breast cancer. The Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) approach can reflect dynamic distribution of contrast agent in tumor vessels, providing important basis for clinical diagnosis. In this study, the efficacy of DCE-MRI on evaluation and prediction of response to NAC in breast cancer was investigated. To this end, fifty-seven cases of malignant breast cancers with MRI examination both before and after two cycle of NAC were analyzed. After pre-processing approach for segmenting breast lesions and background regions, 126-dimensional imaging features were extracted from DCE-MRI. Statistical analyses were then performed to evaluate the associations between the extracted DCE-MRI features and the response to NAC. Specifically, pairwise t test was used to calculate differences of imaging features between MRI examinations before-and-after NAC. Moreover, the associations of these image features with response to NAC were assessed using logistic regression. Significant association are found between response to NAC and the features of lesion morphology and background parenchymal enhancement, especially the feature of background enhancement in normal side of breast (P=0.011). Our study indicate that DCE-MRI features can provide candidate imaging markers to predict response of NAC in breast cancer.

  16. Image quality evaluation of breast tomosynthesis with synchrotron radiation

    SciTech Connect

    Malliori, A.; Bliznakova, K.; Speller, R. D.; Horrocks, J. A.; Rigon, L.; Tromba, G.; Pallikarakis, N.

    2012-09-15

    Purpose: This study investigates the image quality of tomosynthesis slices obtained from several acquisition sets with synchrotron radiation using a breast phantom incorporating details that mimic various breast lesions, in a heterogeneous background. Methods: A complex Breast phantom (MAMMAX) with a heterogeneous background and thickness that corresponds to 4.5 cm compressed breast with an average composition of 50% adipose and 50% glandular tissue was assembled using two commercial phantoms. Projection images using acquisition arcs of 24 Degree-Sign , 32 Degree-Sign , 40 Degree-Sign , 48 Degree-Sign , and 56 Degree-Sign at incident energy of 17 keV were obtained from the phantom with the synchrotron radiation for medical physics beamline at ELETTRA Synchrotron Light Laboratory. The total mean glandular dose was set equal to 2.5 mGy. Tomograms were reconstructed with simple multiple projection algorithm (MPA) and filtered MPA. In the latter case, a median filter, a sinc filter, and a combination of those two filters were applied on the experimental data prior to MPA reconstruction. Visual inspection, contrast to noise ratio, contrast, and artifact spread function were the figures of merit used in the evaluation of the visualisation and detection of low- and high-contrast breast features, as a function of the reconstruction algorithm and acquisition arc. To study the benefits of using monochromatic beams, single projection images at incident energies ranging from 14 to 27 keV were acquired with the same phantom and weighted to synthesize polychromatic images at a typical incident x-ray spectrum with W target. Results: Filters were optimised to reconstruct features with different attenuation characteristics and dimensions. In the case of 6 mm low-contrast details, improved visual appearance as well as higher contrast to noise ratio and contrast values were observed for the two filtered MPA algorithms that exploit the sinc filter. These features are better visualized

  17. Experimental evaluation of a hyperspectral imager for near-infrared fluorescent contrast agent studies

    NASA Astrophysics Data System (ADS)

    Luthman, A. S.; Bohndiek, Sarah E.

    2015-03-01

    Hyperspectral imaging (HSI) systems have the potential to combine morphological and spectral information to provide detailed and high sensitivity readouts in biological and medical applications. As HSI enables simultaneous detection in several spectral bands, the technology has significant potential for use in real-time multiplexed contrast agent studies. Examples include tumor detection in intraoperative and endoscopic imaging as well as histopathology. A multiplexed readout from multiple disease targets, such as cell surface receptors overexpressed in cancer cells, could improve both sensitivity and specificity of tumor identification. Here, we evaluate a commercial, compact, near-infrared HSI sensor that has the potential to enable low cost, video rate HSI for multiplexed fluorescent contrast agent studies in biomedical applications. The hyperspectral imager, based on a monolithically integrated Fabry-Perot etalon, has 70 spectral bands between 600-900 nm, making it ideal for this application. Initial calibration of the imager was performed to determine wavelength band response, quantum efficiency and the effect of F-number on the spectral response. A platform for wide-field fluorescence imaging in reflectance using fluorophore specific LED excitation was then developed. The applicability of the imaging platform for simultaneous readout of multiple fluorophore signals was demonstrated using a dilution series of Alexa Fluor 594 and Alexa Fluor 647, showing that nanomolar fluorophore concentrations can be detected. Our results show that the HSI system can clearly resolve the emission spectra of the two fluorophores in mixtures of concentrations across several orders of magnitude, indicating a high dynamic range performance. We therefore conclude that the HSI sensor tested here is suitable for detecting fluorescence in biomedical imaging applications.

  18. Impulse Response Estimation for Spatial Resolution Enhancement in Ultrasonic NDE Imaging

    SciTech Connect

    Clark, G A

    2004-06-25

    This report describes a signal processing algorithm and MATLAB software for improving spatial resolution in ultrasonic nondestructive evaluation (NDE) imaging of materials. Given a measured reflection signal and an associated reference signal, the algorithm produces an optimal least-squares estimate of the impulse response of the material under test. This estimated impulse response, when used in place of the raw reflection signal, enhances the spatial resolution of the ultrasonic measurements by removing distortion caused by the limited-bandwidth transducers and the materials under test. The theory behind the processing algorithms is briefly presented, while the reader is referred to the bibliography for details. The main focus of the report is to describe how to use the MATLAB software. Two processing examples using actual ultrasonic measurements are provided for tutorial purposes.

  19. SPECT imaging evaluation in movement disorders: far beyond visual assessment.

    PubMed

    Badiavas, Kosmas; Molyvda, Elisavet; Iakovou, Ioannis; Tsolaki, Magdalini; Psarrakos, Kyriakos; Karatzas, Nikolaos

    2011-04-01

    Single photon emission computed tomography (SPECT) imaging with (123)I-FP-CIT is of great value in differentiating patients suffering from Parkinson's disease (PD) from those suffering from essential tremor (ET). Moreover, SPECT with (123)I-IBZM can differentiate PD from Parkinson's "plus" syndromes. Diagnosis is still mainly based on experienced observers' visual assessment of the resulting images while many quantitative methods have been developed in order to assist diagnosis since the early days of neuroimaging. The aim of this work is to attempt to categorize, briefly present and comment on a number of semi-quantification methods used in nuclear medicine neuroimaging. Various arithmetic indices have been introduced with region of interest (ROI) manual drawing methods giving their place to automated procedures, while advancing computer technology has allowed automated image registration, fusion and segmentation to bring quantification closer to the final diagnosis based on the whole of the patient's examinations results, clinical condition and response to therapy. The search for absolute quantification has passed through neuroreceptor quantification models, which are invasive methods that involve tracer kinetic modelling and arterial blood sampling, a practice that is not commonly used in a clinical environment. On the other hand, semi-quantification methods relying on computers and dedicated software try to elicit numerical information out of SPECT images. The application of semi-quantification methods aims at separating the different patient categories solving the main problem of finding the uptake in the structures of interest. The semi-quantification methods which were studied fall roughly into three categories, which are described as classic methods, advanced automated methods and pixel-based statistical analysis methods. All these methods can be further divided into various subcategories. The plethora of the existing semi-quantitative methods reinforces

  20. Evaluation of ZY-3 for Dsm and Ortho Image Generation

    NASA Astrophysics Data System (ADS)

    d'Angelo, P.

    2013-04-01

    DSM generation using stereo satellites is an important topic for many applications. China has launched the three line ZY-3 stereo mapping satellite last year. This paper evaluates the ZY-3 performance for DSM and orthophoto generation on two scenes east of Munich. The direct georeferencing performance is tested using survey points, and the 3D RMSE is 4.5 m for the scene evaluated in this paper. After image orientation with GCPs and tie points, a DSM is generated using the Semi-Global Matching algorithm. For two 5 × 5 km2 test areas, a LIDAR reference DTM was available. After masking out forest areas, the overall RMSE between ZY-3 DSM and LIDAR reference is 2.0 m (RMSE). Additionally, qualitative comparison between ZY-3 and Cartosat-1 DSMs is performed.

  1. Moral Knowledge and Responsibilities in Evaluation Implementation: When Critical Theory and Responsive Evaluation Collide

    ERIC Educational Resources Information Center

    Freeman, Melissa; Preissle, Judith; Havick, Steven

    2010-01-01

    An external evaluation documented what occurred in an inaugural summer camp to teach high school students how to preserve religious freedom by learning about and acting on the history and current state of church-state separation and other first amendment issues. Camp designers hoped to promote religious diversity values and civic engagement in…

  2. Concepts for evaluation of image quality in digital radiology

    NASA Astrophysics Data System (ADS)

    Zscherpel, U.; Ewert, U.; Jechow, M.

    2012-05-01

    Concepts for digital image evaluation are presented for Computed Radiography (CR) and Digital Detector Arrays (DDAs) used for weld inspection. The precise DDA calibration yields an extra ordinary increase of contrast sensitivity up to 10 times in relation to film radiography. Restrictions in spatial resolution caused by pixel size of the DDA are compensated by increased contrast sensitivity. First CR standards were published in 2005 to support the application of phosphor imaging plates in lieu of X-ray film, but they need already a revision based on experiences reported by many users. One of the key concepts is the usage of signal-to-noise (SNR) measurements as equivalent to the optical density of film and film system class. The contrast sensitivity, measured by IQI visibility, depends on three essential parameters: The basic spatial resolution (SRb) of the radiographic image, the achieved signal-to-noise ratio (SNR) and the specific contrast (μeff - effective attenuation coefficient). Knowing these 3 parameters for the given exposure condition, inspected material and monitor viewing condition permits the calculation of the just visible IQI element. Furthermore, this enables the optimization of exposure conditions. The new ISO/FDIS 17636-2 describes the practice for digital radiography with CR and DDAs. It considers the first time compensation principles, derived from the three essential parameters. The consequences are described.

  3. Filter Design and Performance Evaluation for Fingerprint Image Segmentation

    PubMed Central

    Thai, Duy Hoang; Huckemann, Stephan; Gottschlich, Carsten

    2016-01-01

    Fingerprint recognition plays an important role in many commercial applications and is used by millions of people every day, e.g. for unlocking mobile phones. Fingerprint image segmentation is typically the first processing step of most fingerprint algorithms and it divides an image into foreground, the region of interest, and background. Two types of error can occur during this step which both have a negative impact on the recognition performance: ‘true’ foreground can be labeled as background and features like minutiae can be lost, or conversely ‘true’ background can be misclassified as foreground and spurious features can be introduced. The contribution of this paper is threefold: firstly, we propose a novel factorized directional bandpass (FDB) segmentation method for texture extraction based on the directional Hilbert transform of a Butterworth bandpass (DHBB) filter interwoven with soft-thresholding. Secondly, we provide a manually marked ground truth segmentation for 10560 images as an evaluation benchmark. Thirdly, we conduct a systematic performance comparison between the FDB method and four of the most often cited fingerprint segmentation algorithms showing that the FDB segmentation method clearly outperforms these four widely used methods. The benchmark and the implementation of the FDB method are made publicly available. PMID:27171150

  4. Radiological Evaluation of Ambiguous Genitalia with Various Imaging Modalities

    NASA Astrophysics Data System (ADS)

    Ravi, N.; Bindushree, Kadakola

    2012-07-01

    Disorders of sex development (DSDs) are congenital conditions in which the development of chromosomal, gonadal, or anatomic sex is atypical. These can be classified broadly into four categories on the basis of gonadal histologic features: female pseudohermaphroditism (46,XX with two ovaries); male pseudohermaphroditism (46,XY with two testes); true hermaphroditism (ovotesticular DSD) (both ovarian and testicular tissues); and gonadal dysgenesis, either mixed (a testis and a streak gonad) or pure (bilateral streak gonads). Imaging plays an important role in demonstrating the anatomy and associated anomalies. Ultrasonography is the primary modality for demonstrating internal organs and magnetic resonance imaging is used as an adjunct modality to assess for internal gonads and genitalia. Early and appropriate gender assignment is necessary for healthy physical and psychologic development of children with ambiguous genitalia. Gender assignment can be facilitated with a team approach that involves a pediatric endocrinologist, geneticist, urologist, psychiatrist, social worker, neonatologist, nurse, and radiologist, allowing timely diagnosis and proper management. We describe case series on ambiguous genitalia presented to our department who were evaluated with multiple imaging modalities.

  5. Filter Design and Performance Evaluation for Fingerprint Image Segmentation.

    PubMed

    Thai, Duy Hoang; Huckemann, Stephan; Gottschlich, Carsten

    2016-01-01

    Fingerprint recognition plays an important role in many commercial applications and is used by millions of people every day, e.g. for unlocking mobile phones. Fingerprint image segmentation is typically the first processing step of most fingerprint algorithms and it divides an image into foreground, the region of interest, and background. Two types of error can occur during this step which both have a negative impact on the recognition performance: 'true' foreground can be labeled as background and features like minutiae can be lost, or conversely 'true' background can be misclassified as foreground and spurious features can be introduced. The contribution of this paper is threefold: firstly, we propose a novel factorized directional bandpass (FDB) segmentation method for texture extraction based on the directional Hilbert transform of a Butterworth bandpass (DHBB) filter interwoven with soft-thresholding. Secondly, we provide a manually marked ground truth segmentation for 10560 images as an evaluation benchmark. Thirdly, we conduct a systematic performance comparison between the FDB method and four of the most often cited fingerprint segmentation algorithms showing that the FDB segmentation method clearly outperforms these four widely used methods. The benchmark and the implementation of the FDB method are made publicly available. PMID:27171150

  6. Evaluation of laser prostatectomy devices by thermal imaging

    NASA Astrophysics Data System (ADS)

    Molenaar, David G.; van Vliet, Remco J.; van Swol, Christiaan F. P.; Boon, Tom A.; Verdaasdonck, Rudolf M.

    1994-12-01

    The treatment of benign prostatic hyperplasia (BPH) using Nd:YAG laser light has become an accepted alternative to TURP. However, there is no consensus to the dosimetry using the various laser devices. In our study, we evaluate the optical and thermal characteristics of 7 commercially available side firing laser probes. For the thermal analysis, an optical method was used based on `Schlieren' techniques producing color images of the temperature distribution around the laser probe in water. Absolute temperatures were obtained after calibration measurements with thermocouples. Laser probes using metal mirrors for beam deflection heated up entirely. The local temperature rose up to 100 degrees centigrade, thus inducing vapor bubble formation that interfered with the emitted beam. Laser devices, using total internal reflection for deflection, showed far less heating primarily at the exit window, though Fresnel reflections and secondary beams indirectly heated up the (metal) housing of the tip. After clinical application, the absorption at the probe surface and hence temperature increased due to probe deterioration. Color Schlieren imaging is a powerful method for the thermal evaluation of laser devices. The thermal behavior of laser probes can be used as a guidance for the method of application and as an indication of the lifetime of the probes.

  7. Dose-Response Evaluation of Braslet-M Occlusion Cuffs

    NASA Technical Reports Server (NTRS)

    Ebert, Douglas; Garcia, Kathleen; Sargsyan, Ashot E.; Ham, David; Hamilton, Douglas; Dulchavsky, Scott A.

    2010-01-01

    Introduction: Braslet-M is a set of special elasticized thigh cuffs used by the Russian space agency to reduce the effects of the head-ward fluid shift during early adaptation to microgravity by sequestering fluid in the lower extremities. Currently, no imaging modalities are used in the calibration of the device, and the pressure required to produce a predictable physiological response is unknown. This investigation intends to relate the pressure exerted by the cuffs to the extent of fluid redistribution and commensurate physiological effects. Materials and Methods: Ten healthy subjects with standardized fluid intake participated in the study. Data collection included femoral and internal jugular vein imaging in two orthogonal planes, pulsed Doppler of cervical and femoral vessels and middle cerebral artery, optic nerve imaging, and echocardiography. Braslet-M cuff pressure was monitored at the skin interface using pre-calibrated pressure sensors. Using 6 and 30 head-down tilt in two separate sessions, the effect of Braslet-M was assessed while incrementally tightening the cuffs. Cuffs were then simultaneously released to document the resulting hemodynamic change. Results: Preliminary analysis shows correlation between physical pressure exerted by the Braslet-M device and several parameters such as jugular and femoral vein cross-sections, resistivity of the lower extremity vascular bed, and others. A number of parameters reflect blood redistribution and will be used to determine the therapeutic range of the device and to prevent unsafe application. Conclusion: Braslet-M exerts a physical effect that can be measured and correlated with many changes in central and peripheral hemodynamics. Analysis of the full data set will be required to make definitive recommendations regarding the range of safe therapeutic application. Objective data and subjective responses suggest that a safer and equally effective use of Braslet can be achieved when compared with the current

  8. In vitro evaluation of fluorescence glucose biosensor response.

    PubMed

    Aloraefy, Mamdouh; Pfefer, T Joshua; Ramella-Roman, Jessica C; Sapsford, Kim E

    2014-01-01

    Rapid, accurate, and minimally-invasive glucose biosensors based on Förster Resonance Energy Transfer (FRET) for glucose measurement have the potential to enhance diabetes control. However, a standard set of in vitro approaches for evaluating optical glucose biosensor response under controlled conditions would facilitate technological innovation and clinical translation. Towards this end, we have identified key characteristics and response test methods, fabricated FRET-based glucose biosensors, and characterized biosensor performance using these test methods. The biosensors were based on competitive binding between dextran and glucose to concanavalin A and incorporated long-wavelength fluorescence dye pairs. Testing characteristics included spectral response, linearity, sensitivity, limit of detection, kinetic response, reversibility, stability, precision, and accuracy. The biosensor demonstrated a fluorescence change of 45% in the presence of 400 mg/dL glucose, a mean absolute relative difference of less than 11%, a limit of detection of 25 mg/dL, a response time of 15 min, and a decay in fluorescence intensity of 72% over 30 days. The battery of tests presented here for objective, quantitative in vitro evaluation of FRET glucose biosensors performance have the potential to form the basis of future consensus standards. By implementing these test methods for a long-visible-wavelength biosensor, we were able to demonstrate strengths and weaknesses with a new level of thoroughness and rigor. PMID:25006996

  9. Effects of some anesthetic agents on skin microcirculation evaluated by laser Doppler perfusion imaging in mice

    PubMed Central

    2013-01-01

    Background Anesthetic agents alter microcirculation, influencing tissue oxygenation and delivery of vital substrates. Laser Doppler perfusion imaging is a widespread technique in the field of microvascular research that can evaluate noninvasively and in real time the effects of environmental conditions, physical manipulations, diseases and treatments on peripheral perfusion. This study aims to evaluate laser Doppler perfusion imaging as a means to detect changes in skin microcirculation induced by some popular anesthetic agents in a murine model. Twenty-four age- and gender-matched healthy CD1 mice were examined by laser Doppler perfusion imaging. The skin microcirculatory response was measured at the level of plantar surfaces during isoflurane anesthesia with or without subsequent dexmedetomidine or acepromazine. At the end of the procedure, dexmedetomidine was reversed by atipamezole administration. Results In all mice, skin blood flow under isoflurane anesthesia did not show significant differences over time (P = 0.1). The serial perfusion pattern and values following acepromazine or dexmedetomidine administration differed significantly (P < 0.05). Conclusions We standardized a reliable laser Doppler perfusion imaging protocol to non-invasively assess changes in skin microcirculation induced by anesthesia in mice, considering the advantages and drawbacks of this technique and its translational value. PMID:24341447

  10. Association between dynamic features of breast DCE-MR imaging and clinical response of neoadjuvant chemotherapy: a preliminary analysis

    NASA Astrophysics Data System (ADS)

    Huang, Lijuan; Fan, Ming; Li, Lihua; Zhang, Juan; Shao, Guoliang; Zheng, Bin

    2016-03-01

    Neoadjuvant chemotherapy (NACT) is being used increasingly in the management of patients with breast cancer for systemically reducing the size of primary tumor before surgery in order to improve survival. The clinical response of patients to NACT is correlated with reduced or abolished of their primary tumor, which is important for treatment in the next stage. Recently, the dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is used for evaluation of the response of patients to NACT. To measure this correlation, we extracted the dynamic features from the DCE- MRI and performed association analysis between these features and the clinical response to NACT. In this study, 59 patients are screened before NATC, of which 47 are complete or partial response, and 12 are no response. We segmented the breast areas depicted on each MR image by a computer-aided diagnosis (CAD) scheme, registered images acquired from the sequential MR image scan series, and calculated eighteen features extracted from DCE-MRI. We performed SVM with the 18 features for classification between patients of response and no response. Furthermore, 6 of the 18 features are selected to refine the classification by using Genetic Algorithm. The accuracy, sensitivity and specificity are 87%, 95.74% and 50%, respectively. The calculated area under a receiver operating characteristic (ROC) curve is 0.79+/-0.04. This study indicates that the features of DCE-MRI of breast cancer are associated with the response of NACT. Therefore, our method could be helpful for evaluation of NACT in treatment of breast cancer.

  11. Evaluation of Piloted Inputs for Onboard Frequency Response Estimation

    NASA Technical Reports Server (NTRS)

    Grauer, Jared A.; Martos, Borja

    2013-01-01

    Frequency response estimation results are presented using piloted inputs and a real-time estimation method recently developed for multisine inputs. A nonlinear simulation of the F-16 and a Piper Saratoga research aircraft were subjected to different piloted test inputs while the short period stabilator/elevator to pitch rate frequency response was estimated. Results show that the method can produce accurate results using wide-band piloted inputs instead of multisines. A new metric is introduced for evaluating which data points to include in the analysis and recommendations are provided for applying this method with piloted inputs.

  12. Preliminary investigation fo the non-linear response of image intensifiers used for gamma-ray imaging

    NASA Astrophysics Data System (ADS)

    Fastje, David; Barber, H. Bradford; Bora, Vaibhav; Lemieux, Daniel; Miller, Brian; Grim, Gary P.

    2013-09-01

    Image intensifiers combined with columnar scintillators have found application in x-ray and gamma-ray, biomedical imaging and other fields. In scintillator imaging, hundreds or thousands of optical photons can illuminate the faceplate of the image intensifier in a small area, essentially simultaneously. This is a situation not found in the typical design application for an image intensifier, night vision or low-light-level imaging. Microchannel plates (MCPs) are known to exhibit gain saturation that could result in non-linear signal response in scintillator imaging, limiting quantitative measurement capabilities. A calibrated LED photon source was developed that can provide a known average number of photons per unit area in a small spot size, similar to that seen due to a gamma-ray interaction in a BazookaSPECT imager. A BazookaSPECT imager is composed of a columnar scintillator and an image intensifier, with output light optically imaged onto a CCD camera. The calibrated source was used to investigate gain-saturation effects for two Proxivision, GmbH image intensifiers, a single-stage BV 2583 EZ and a two stage BV 2583 QZ-V 100N in a BazookaSPECT imaging configuration. No gain saturation was found for the single-stage image intensifier up to more than 100 optical photons per microchannel, but significant gain-saturation non-linearities were measured in the two-stage image intensifier at high gains for >12 optical photons per microchannel. Implications for scintillator imaging using such systems are discussed.

  13. The Influence of Corporate Image and Specificity of Candidate Qualifications on Response to Recruitment Advertisement.

    ERIC Educational Resources Information Center

    Belt, John A.; Paolillo, Joseph G. P.

    1982-01-01

    Examined possible impact of corporate image and the degree of specificity of candidate qualifications, on likelihood of reader response to recruitment advertisement. Data indicated that corporate image of advertiser significantly influenced likelihood of reader response whereas degree of specificity of candidate qualifications did not influence…

  14. 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.

  15. Comparison of magnetic resonance imaging and radionuclide imaging in the evaluation of renal transplant failure

    SciTech Connect

    Goldsmith, M.S.; Tanasescu, D.E.; Waxman, A.D.; Crues, J.V. III

    1988-04-01

    Magnetic resonance imaging (MRI) was compared with radionuclide scintigraphy (RNS) in 16 patients with renal transplants undergoing renal failure to determine which modality could best discriminate between rejection, acute tubular necrosis (ATN), and cyclosporin nephrotoxicity (CN). Although all rejecting transplants had reduced corticomedullary differentiation (CMD) on T1-weighted MR images, four of five cases of ATN had appearances that could not be distinguished from rejection. A normal CMD suggests nonrejection, but diminished CMD is nonspecific. Tc-99m DTPA/I-131 hippuran RNS was superior to MRI in differentiating rejection from ATN. Although ATN and CN have similar RNS patterns, this distinction can usually be made based on the clinical time course. Other potential uses of MRI in the evaluation of the renal transplants are discussed.

  16. Implementation and evaluation of various demons deformable image registration algorithms on a GPU

    NASA Astrophysics Data System (ADS)

    Gu, Xuejun; Pan, Hubert; Liang, Yun; Castillo, Richard; Yang, Deshan; Choi, Dongju; Castillo, Edward; Majumdar, Amitava; Guerrero, Thomas; Jiang, Steve B.

    2010-01-01

    Online adaptive radiation therapy (ART) promises the ability to deliver an optimal treatment in response to daily patient anatomic variation. A major technical barrier for the clinical implementation of online ART is the requirement of rapid image segmentation. Deformable image registration (DIR) has been used as an automated segmentation method to transfer tumor/organ contours from the planning image to daily images. However, the current computational time of DIR is insufficient for online ART. In this work, this issue is addressed by using computer graphics processing units (GPUs). A gray-scale-based DIR algorithm called demons and five of its variants were implemented on GPUs using the compute unified device architecture (CUDA) programming environment. The spatial accuracy of these algorithms was evaluated over five sets of pulmonary 4D CT images with an average size of 256 × 256 × 100 and more than 1100 expert-determined landmark point pairs each. For all the testing scenarios presented in this paper, the GPU-based DIR computation required around 7 to 11 s to yield an average 3D error ranging from 1.5 to 1.8 mm. It is interesting to find out that the original passive force demons algorithms outperform subsequently proposed variants based on the combination of accuracy, efficiency and ease of implementation.

  17. The development and evaluation of head probes for optical imaging of the infant head

    NASA Astrophysics Data System (ADS)

    Branco, Gilberto

    The objective of this thesis was to develop and evaluate optical imaging probes for mapping oxygenation and haemodynamic changes in the newborn infant brain. Two imaging approaches are being developed at University College London (UCL): optical topography (surface mapping of the cortex) and optical tomography (volume imaging). Both have the potential to provide information about the function of the normal brain and about a variety of neurophysiologies! abnormalities. Both techniques require an array of optical fibres/fibre bundles to be held in contact with the head, for periods of time from tens of seconds to an hour or more. The design of suitable probes must ensure the comfort and safety of the subject, and provide measurements minimally sensitive to external sources of light and patient motion. A series of prototype adaptable helmets were developed for optical tomography of the premature infant brain using the UCL 32-channel time-resolved system. They were required to attach 32 optical fibre bundles over the infant scalp, and were designed to accommodate infants with a variety of head shapes and sizes, aged between 24-weeks gestational age and term. Continual improvements to the helmet design were introduced following the evaluation of each prototype on infants in the hospital. Data were acquired to generate images revealing the concentration and oxygenation of blood in the brain, and the response of the brain to sensory stimulation. This part of the project also involved designing and testing new methods of acquiring calibration data using reference phantoms. The second focus of the project was the development of probes for use with the UCL frequency-multiplexed near-infrared topography system. This is being used to image functional activation in the infant cortex. A series of probes were developed and experiments were conducted to evaluate their sensitivity to patient motion and to compression of the probe. The probes have been used for a variety of

  18. Impact of more detailed categorization of shrinkage or progression ratio at initial imaging response after sorafenib treatment in advanced hepatocellular carcinoma patients

    PubMed Central

    Wada, Yoshiyuki; Takami, Yuko; Tateishi, Masaki; Ryu, Tomoki; Mikagi, Kazuhiro; Saitsu, Hideki

    2015-01-01

    Background Sorafenib therapy improves survival in unresectable hepatocellular carcinoma (HCC) patients without an objective response. The present study investigated whether the initial imaging response might be a prognostic indicator after administration of sorafenib therapy in HCC patients. Patients and methods This retrospective study reviewed unresectable HCC patients undergoing sorafenib therapy. Patients evaluated without complete response, partial response (PR), or progressive disease (PD) at the initial imaging response evaluation by modified Response Evaluation Criteria in Solid Tumors were divided into three groups according to more detailed categorization of the shrinkage/progression ratio in initial imaging response. A comparison of progression-free and overall survival among these groups was performed. Results Of the 43 non-PR non-PD patients with target lesions, ten (23.3%) exhibited mild response (MR; −30% to −5%), 14 (32.6%) exhibited no change (NC; −5% to +5%), and 19 (44.2%) exhibited mild-PD (MPD; +5% to +20%). There was no statistical difference in progression-free or overall survival between MR and NC patients. The median progression-free survivals in NC+MR and mild-PD patients were 15.0 and 5.3 months, respectively (P<0.01), and the median survival times were 31.9 and 17.1 months, respectively (P<0.001). In multivariate analysis, etiology (hepatitis C virus) and initial imaging response (MR+NC) was identified as an independently good prognostic factor. Conclusion More detailed categorization of shrinkage or progression at the initial imaging response evaluation may be a useful marker for predicting sorafenib treatment outcomes in HCC patients. If the initial imaging response is not progression but stability, sorafenib may have a survival benefit. PMID:26586953

  19. Evaluation of the Response to the Fukushima Accident.

    PubMed

    Miska, Horst

    2016-08-01

    The cause for the severity of the Fukushima nuclear accident is explained, and the radiological consequences are assessed. Moreover, the non-radiological effects are critically evaluated and failures in onsite and offsite emergency response highlighted. In conclusion, disregarding the principle of justification, the evacuation of residents and hospital patients was implemented too rigorously, resulting in unnecessary fatalities due to the protective action. PMID:27356068

  20. Overcoming the concentration-dependence of responsive probes for magnetic resonance imaging

    PubMed Central

    Ekanger, Levi A.

    2015-01-01

    In magnetic resonance imaging, contrast agents are molecules that increase the contrast-to-noise ratio of non-invasively acquired images. The information gained from magnetic resonance imaging can be increased using responsive contrast agents that undergo chemical changes, and consequently changes to contrast enhancement, for example in response to specific biomarkers that are indicative of diseases. A major limitation with modern responsive contrast agents is concentration-dependence that requires the concentration of contrast agent to be known: an extremely challenging task in vivo. Here, we review advances in several strategies aimed at overcoming the concentration-dependent nature of responsive contrast agents. PMID:25579206

  1. Human vision model for the objective evaluation of perceived image quality applied to MRI and image restoration

    NASA Astrophysics Data System (ADS)

    Salem, Kyle A.; Wilson, David L.

    2002-12-01

    We are developing a method to objectively quantify image quality and applying it to the optimization of interventional magnetic resonance imaging (iMRI). In iMRI, images are used for live-time guidance of interventional procedures such as the minimally invasive treatment of cancer. Hence, not only does one desire high quality images, but they must also be acquired quickly. In iMRI, images are acquired in the Fourier domain, or k-space, and this allows many creative ways to image quickly such as keyhole imaging where k-space is preferentially subsampled, yielding suboptimal images at very high frame rates. Other techniques include spiral, radial, and the combined acquisition technique. We have built a perceptual difference model (PDM) that incorporates various components of the human visual system. The PDM was validated using subjective image quality ratings by naive observers and task-based measures defined by interventional radiologists. Using the PDM, we investigated the effects of various imaging parameters on image quality and quantified the degradation due to novel imaging techniques. Results have provided significant information about imaging time versus quality tradeoffs aiding the MR sequence engineer. The PDM has also been used to evaluate other applications such as Dixon fat suppressed MRI and image restoration. In image restoration, the PDM has been used to evaluate the Generalized Minimal Residual (GMRES) image restoration method and to examine the ability to appropriately determine a stopping condition for such iterative methods. The PDM has been shown to be an objective tool for measuring image quality and can be used to determine the optimal methodology for various imaging applications.

  2. Cavernosal nerve functionality evaluation after magnetic resonance imaging-guided transurethral ultrasound treatment of the prostate

    PubMed Central

    Sammet, Steffen; Partanen, Ari; Yousuf, Ambereen; Sammet, Christina L; Ward, Emily V; Wardrip, Craig; Niekrasz, Marek; Antic, Tatjana; Razmaria, Aria; Farahani, Keyvan; Sokka, Shunmugavelu; Karczmar, Gregory; Oto, Aytekin

    2015-01-01

    AIM: To evaluate the feasibility of using therapeutic ultrasound as an alternative treatment option for organ-confined prostate cancer. METHODS: In this study, a trans-urethral therapeutic ultrasound applicator in combination with 3T magnetic resonance imaging (MRI) guidance was used for real-time multi-planar MRI-based temperature monitoring and temperature feedback control of prostatic tissue thermal ablation in vivo. We evaluated the feasibility and safety of MRI-guided trans-urethral ultrasound to effectively and accurately ablate prostate tissue while minimizing the damage to surrounding tissues in eight canine prostates. MRI was used to plan sonications, monitor temperature changes during therapy, and to evaluate treatment outcome. Real-time temperature and thermal dose maps were calculated using the proton resonance frequency shift technique and were displayed as two-dimensional color-coded overlays on top of the anatomical images. After ultrasound treatment, an evaluation of the integrity of cavernosal nerves was performed during prostatectomy with a nerve stimulator that measured tumescence response quantitatively and indicated intact cavernous nerve functionality. Planned sonication volumes were visually correlated to MRI ablation volumes and corresponding histo-pathological sections after prostatectomy. RESULTS: A total of 16 sonications were performed in 8 canines. MR images acquired before ultrasound treatment were used to localize the prostate and to prescribe sonication targets in all canines. Temperature elevations corresponded within 1 degree of the targeted sonication angle, as well as with the width and length of the active transducer elements. The ultrasound treatment procedures were automatically interrupted when the temperature in the target zone reached 56 °C. In all canines erectile responses were evaluated with a cavernous nerve stimulator post-treatment and showed a tumescence response after stimulation with an electric current. These

  3. Choline molecular imaging with small-animal PET for monitoring tumor cellular response to photodynamic therapy of cancer

    NASA Astrophysics Data System (ADS)

    Fei, Baowei; Wang, Hesheng; Wu, Chunying; Meyers, Joseph; Xue, Liang-Yan; MacLennan, Gregory; Schluchter, Mark

    2009-02-01

    We are developing and evaluating choline molecular imaging with positron emission tomography (PET) for monitoring tumor response to photodynamic therapy (PDT) in animal models. Human prostate cancer (PC-3) was studied in athymic nude mice. A second-generation photosensitizer Pc 4 was used for PDT in tumor-bearing mice. MicroPET images with 11C-choline were acquired before PDT and 48 h after PDT. Time-activity curves of 11C-choline uptake were analyzed before and after PDT. For treated tumors, normalized choline uptake decreased significantly 48 h after PDT, compared to the same tumors pre-PDT (p <~ 0.001). However, for the control tumors, normalized choline uptake increased significantly (p <~ 0.001). PET imaging with 11C-choline is sensitive to detect early tumor response to PDT in the animal model of human prostate cancer.

  4. ATP-Responsive and Near-Infrared-Emissive Nanocarriers for Anticancer Drug Delivery and Real-Time Imaging

    PubMed Central

    Qian, Chenggen; Chen, Yulei; Zhu, Sha; Yu, Jicheng; Zhang, Lei; Feng, Peijian; Tang, Xin; Hu, Quanyin; Sun, Wujin; Lu, Yue; Xiao, Xuanzhong; Shen, Qun-Dong; Gu, Zhen

    2016-01-01

    Stimuli-responsive and imaging-guided drug delivery systems hold vast promise for enhancement of therapeutic efficacy. Here we report an adenosine-5'-triphosphate (ATP)-responsive and near-infrared (NIR)-emissive conjugated polymer-based nanocarrier for the controlled release of anticancer drugs and real-time imaging. We demonstrate that the conjugated polymeric nanocarriers functionalized with phenylboronic acid tags on surface as binding sites for ATP could be converted to the water-soluble conjugated polyelectrolytes in an ATP-rich environment, which promotes the disassembly of the drug carrier and subsequent release of the cargo. In vivo studies validate that this formulation exhibits promising capability for inhibition of tumor growth. We also evaluate the metabolism process by monitoring the fluorescence signal of the conjugated polymer through the in vivo NIR imaging. PMID:27217838

  5. ATP-Responsive and Near-Infrared-Emissive Nanocarriers for Anticancer Drug Delivery and Real-Time Imaging.

    PubMed

    Qian, Chenggen; Chen, Yulei; Zhu, Sha; Yu, Jicheng; Zhang, Lei; Feng, Peijian; Tang, Xin; Hu, Quanyin; Sun, Wujin; Lu, Yue; Xiao, Xuanzhong; Shen, Qun-Dong; Gu, Zhen

    2016-01-01

    Stimuli-responsive and imaging-guided drug delivery systems hold vast promise for enhancement of therapeutic efficacy. Here we report an adenosine-5'-triphosphate (ATP)-responsive and near-infrared (NIR)-emissive conjugated polymer-based nanocarrier for the controlled release of anticancer drugs and real-time imaging. We demonstrate that the conjugated polymeric nanocarriers functionalized with phenylboronic acid tags on surface as binding sites for ATP could be converted to the water-soluble conjugated polyelectrolytes in an ATP-rich environment, which promotes the disassembly of the drug carrier and subsequent release of the cargo. In vivo studies validate that this formulation exhibits promising capability for inhibition of tumor growth. We also evaluate the metabolism process by monitoring the fluorescence signal of the conjugated polymer through the in vivo NIR imaging. PMID:27217838

  6. Evaluating CFRP-Masonry Bond Using Thermal Imaging

    NASA Astrophysics Data System (ADS)

    Ross, Joseph C.

    This study presents results from non-destructive testing to evaluate the degradation of the CFRP-masonry bond using thermal imaging. The goal of the research was to identify locations where there was evidence of bond deterioration that could subsequently be verified through destructive pull-off testing. Four full-scale masonry walls were built outdoors at the University of South Florida in 1995 to evaluate the effectiveness of CFRP for repairing settlement damage. Two of the settlement-damaged walls were repaired using single layer, commercially available unidirectional CFRP systems that used Tonen (wall 3) and Henkel (wall 2) epoxies. These two walls were the subject of this investigation. Before non-destructive tests were initiated, historical site data on temperature, humidity and rainfall variation was compiled. Over seventeen years, the walls experienced ambient temperatures as high as 98°F and as low as 25°F. The average rainfall in Tampa is about 34 inches and the annual average high humidity is around 87%. Because of the high temperature and humidity, the CFRP-masonry bond was exposed to a particularly aggressive environment. Three types of thermal evaluation were carried out: thermocouple monitoring and both passive (solar) and active (localized heating) infrared thermal imaging. Twenty-four thermocouples were used to observe the spatial variations in temperature on the wall. Data showed that the surface temperatures of the wall are uneven with one end being hotter than the other. Measurements indicated that the wall temperatures went as high as 103°F during the week of data collection in late March and early April of 2012. In contrast, the highest ambient temperature over the same period was 92°F. The high temperature experienced by the wall is below the glass transition temperature for the epoxies, which ranges from 140°F to 180°F. A FLIR Tau 320 thermal imaging camera was used to identify localized de-bonding. Solar radiation heated the walls and

  7. Automatic quantitative evaluation of image registration techniques with the ɛ dissimilarity criterion in the case of retinal images

    NASA Astrophysics Data System (ADS)

    Gavet, Yann; Fernandes, Mathieu; Pinoli, Jean-Charles

    2011-07-01

    In human retina observation (with non mydriatic optical microscopes), a registration process is often employed to enlarge the field of view. For the ophthalmologist, this is a way to spare time browsing all the images. A lot of techniques have been proposed to perform this registration process, and indeed, its good evaluation is a question that can be raised. This article presents the use of the ɛ dissimilarity criterion to evaluate and compare some classical featurebased image registration techniques. The problem of retina images registration is employed as an example, but it could also be used in other applications. The images are first segmented and these segmentations are registered. The good quality of this registration is evaluated with the dissimilarity criterion for 25 pairs of images with a manual selection of control points. This study can be useful in order to choose the type of registration method and to evaluate the results of a new one.

  8. Image-guided Treatment in the Hepatobiliary System: Role of Imaging in Treatment Planning and Posttreatment Evaluation.

    PubMed

    Bajpai, Surabhi; Kambadakone, Avinash; Guimaraes, Alexander R; Arellano, Ronald S; Gervais, Debra A; Sahani, Dushyant

    2015-01-01

    In the past decade, image-guided targeted treatments such as percutaneous ablation, intra-arterial embolic therapies, and targeted radiation therapy have shown substantial promise in management of hepatobiliary malignancies. Imaging is integral to patient selection, treatment delivery, and assessment of treatment effectiveness. Preprocedural imaging is crucial and allows local tumor staging, evaluation of surrounding structures, and selection of suitable therapeutic options and strategies for treatment delivery. Postprocedural imaging is required to monitor therapeutic success, detect residual or recurrent disease, and identify procedure-related complications to guide appropriate future therapy. Technical innovations in cross-sectional imaging techniques such as computed tomography (CT) and magnetic resonance (MR) imaging, combined with advances in image postprocessing and new types of contrast agents, allow precise morphologic assessment and functional evaluation of hepatobiliary tumors. Advanced postprocessing techniques such as image fusion and volumetric assessment not only facilitate procedural planning and treatment delivery but also enhance posttreatment imaging surveillance. In addition, molecular imaging techniques such as fluorodeoxyglucose positron emission tomography (PET), PET/CT, and PET/MR imaging offer opportunities to evaluate various physiologic properties of tumors. PMID:26252365

  9. Evaluation of Selected Features for CAR Detection in Aerial Images

    NASA Astrophysics Data System (ADS)

    Tuermer, S.; Leitloff, J.; Reinartz, P.; Stilla, U.

    2011-09-01

    The extraction of vehicles from aerial images provides a wide area traffic situation within a short time. Applications for the gathered data are various and reach from smart routing in the case of congestions to usability validation of roads in the case of disasters. The challenge of the vehicle detection task is finding adequate features which are capable to separate cars from other objects; especially those that look similar. We present an experiment where selected features show their ability of car detection. Precisely, Haar-like and HoG features are utilized and passed to the AdaBoost algorithm for calculating the final detector. Afterwards the classifying power of the features is accurately analyzed and evaluated. The tests a carried out on aerial data from the inner city of Munich, Germany and include small inner city roads with rooftops close by which raise the complexity factor.

  10. Recent advances in PET imaging for evaluation of Parkinson's disease.

    PubMed

    Sioka, Chrissa; Fotopoulos, Andreas; Kyritsis, Athanassios P

    2010-08-01

    Parkinson's disease (PD) consists of loss of pigmented dopamine-secreting neurons in the pars compacta of the midbrain substantia nigra. These neurons project to the striatum (putamen and caudate nucleus) and their loss leads to alterations in the activity of the neural circuits that regulate movement. In a simplified model, two dopamine pathways are involved: the direct pathway, which is mediated through facilitation of the D(1) receptors, and the indirect pathway through D(2) receptors (inhibitory). Positron emission tomography (PET) tracers to image the presynaptic sites of the dopaminergic system include 6-[(18)F]FDOPA and 6-[(18)F]FMT, [(11)C]dihydrotetrabenazine, [(11)C]nomifensine and various radiolabelled cocaine derivatives. Postsynaptically, for the dopamine D(1) subtype the most commonly used ligands are [(11)C]SCH 23390 or [(11)C]NNC 112 and for the D(2) subtype [(11)C]raclopride, [(11)C]MNPA and [(18)F]DMFP. PET is a sensitive and specific non-invasive molecular imaging technique that may be helpful for evaluation of PD and its differential diagnosis from other parkinsonian syndromes. PMID:20107789

  11. Imaging components for a robotic casualty evaluation system.

    PubMed

    Wong, Kenneth H; Lob, Shih-Chung; Lin, Ching-Fang; Lasser, Bob; Mun, Seong K

    2009-01-01

    Combat medics have a vital role in the protection of wounded soldiers in the battlespace. However, their duties expose them to great risks. Furthermore, these medics are a limited resource and must be carefully tasked in order to provide maximum benefit to their units. For these reasons, we are applying the American GNC Corporation's (AGNC) Coremicro(R) Robotic System for autonomous evaluation of battlefield casualties. These robots are intended to navigate to a casualty, determine his/her overall health status, and perform limited diagnostic imaging in order to assess the presence of injuries that would prevent or complicate extraction. In this paper, we describe development work on some of the key components of the proposed robotic system, namely the overall concept of operations (ConOps) and initial testing of infrared and ultrasound imaging cameras. When fully deployed, this system will act as a medical force multiplier, enabling improved care of wounded soldiers and protecting the health and safety of military medical personnel. PMID:19964740

  12. An evaluation of imaging spectrometry for estimating forest canopy chemistry

    NASA Technical Reports Server (NTRS)

    Wessman, Carol A.; Aber, John D.; Peterson, David L.

    1989-01-01

    High spectral resolution Airborne Imaging Spectrometer (AIS) data were acquired over 20 well-studied Wisconsin forest sites to evaluate the potential of remote sensing for estimating forest canopy chemistry. Intensive nutrient cycling research in these forests demonstrates that canopy lignin content is strongly related to measured annual nitrogen mineralization at the undisturbed sites and may serve as an accurate index for nitrogen cycling rates. Ground measurements were made of foliar biomass and canopy nitrogen and lignin content, the latter within two weeks of the AIS overflight. The spectral data were transformed using derivative techniques modified from laboratroy spectroscopy. Stepwise regression assisted in determining combinations of wavelengths most highly correlated with canopy chemistry and biomass. Strong correlations between AIS data and total canopy lignin content in deciduous forests and canopy lignin concentration (total lignin/biomass) in both deciduous and coniferous stands indicate that imaging spectrometry can be used to estimate canopy lignin content and, from that, the spatial distribution of annual nitrogen mineralization rates.

  13. Signal-to-noise ratio analysis and evaluation of the Hadamard imaging technique

    NASA Technical Reports Server (NTRS)

    Jobson, D. J.; Katzberg, S. J.; Spiers, R. B., Jr.

    1977-01-01

    The signal-to-noise ratio performance of the Hadamard imaging technique is analyzed and an experimental evaluation of a laboratory Hadamard imager is presented. A comparison between the performances of Hadamard and conventional imaging techniques shows that the Hadamard technique is superior only when the imaging objective lens is required to have an effective F (focus) number of about 2 or slower.

  14. Unidimensional Measurement May Evaluate Target Lymph Nodal Response After Induction Chemotherapy for Nasopharyngeal Carcinoma

    PubMed Central

    Chen, Chuanben; Zhang, Mingwei; Xu, Yuanji; Yue, Qiuyuan; Bai, Penggang; Zhou, Lin; Xiao, Youping; Zheng, Dechun; Lin, Kongqi; Qiu, Sufang; Chen, Yunbin; Pan, Jianji

    2016-01-01

    Abstract The aim of the study was to evaluate whether short axis and long axis on axial and coronal magnetic resonance imaging planes would reflect the tumor burden or alteration in size after induction chemotherapy in nasopharyngeal carcinoma. Patients with pathologically confirmed nasopharyngeal carcinoma (n = 37) with at least 1 positive cervical lymph node (axial short axis ≥15 mm) were consecutively enrolled in this prospective study. Lymph nodal measurements were performed along its short axis and long axis in both axial and coronal magnetic resonance imaging planes at diagnosis and after 2 cycles of induction chemotherapy. In addition, lymph nodal volumes were automatically calculated in 3D treatment-planning system, which were used as reference standard. Student's t test or nonparametric Mann–Whitney U test was used to compare the continuous quantitative variables. Meanwhile, the κ statistic and McNemar's test were used to evaluate the degree of agreement and discordance in response categorization among different measurements. Axial short axis was significantly associated with volumes at diagnosis (P < 0.001). A good agreement (κ=0.583) was found between axial short axis and volumetric criteria. However, the inconsistent lymph nodal shrinkage in 4 directions was observed. Axial short-axis shrinking was more rapid than the other 3 parameters. Interestingly, when utilizing the alternative planes for unidimensional measurements to assess tumor response, coronal short-axis showed the best concordance (κ=0.792) to the volumes. Axial short axis may effectively reflect tumor burden or change in tumor size in the assessment of target lymph nodal response after induction chemotherapy for nasopharyngeal carcinoma. However, it should be noted that axial short axis may amplify the therapeutic response. In addition, the role of coronal short axis in the assessment of tumor response needs further evaluation. PMID:26945354

  15. Hepatocellular Carcinoma and Diffusion-Weighted MRI: Detection and Evaluation of Treatment Response.

    PubMed

    Gluskin, Jill S; Chegai, Fabrizio; Monti, Serena; Squillaci, Ettore; Mannelli, Lorenzo

    2016-01-01

    Differentiating between cancerous tissue and healthy liver parenchyma could represent a challenge with the only conventional Magnetic Resonance (MR) imaging. Diffusion weighted imaging (DWI) exploits different tissue characteristics to conventional Magnetic Resonance Imaging (MRI) sequences that enhance hepatocellular carcinoma (HCC) detection, characterization, and post-treatment evaluation. Detection of HCC is improved by DWI, infact this technology increases conspicuity of lesions that might otherwise not be identified due to obscuration by adjacent vessels or due to low contrast between the lesion and background liver. It is important to remember that DWI combined with contrast-enhanced MRI has higher sensitivity than DWI alone, and that some patients are not eligible for use of contrast on CT and MRI; in these patients DWI has a prominent role. MRI has advanced beyond structural anatomic imaging to now showing pathophysiologic processes. DWI is a promising way to characterize lesions utilizing the inherent contrast within the liver and has the benefit of not requiring contrast injection. DWI improves detection and characterization of HCC. Proposed clinical uses for DWI include: assessing prognosis, predicting response, monitoring response to therapy, and distinguishing tumor recurrence from treatment effect. Ideally, DWI will help risk stratify patients and will participate in prognostic modeling. PMID:27471573

  16. Hepatocellular Carcinoma and Diffusion-Weighted MRI: Detection and Evaluation of Treatment Response

    PubMed Central

    Gluskin, Jill S; Chegai, Fabrizio; Monti, Serena; Squillaci, Ettore; Mannelli, Lorenzo

    2016-01-01

    Differentiating between cancerous tissue and healthy liver parenchyma could represent a challenge with the only conventional Magnetic Resonance (MR) imaging. Diffusion weighted imaging (DWI) exploits different tissue characteristics to conventional Magnetic Resonance Imaging (MRI) sequences that enhance hepatocellular carcinoma (HCC) detection, characterization, and post-treatment evaluation. Detection of HCC is improved by DWI, infact this technology increases conspicuity of lesions that might otherwise not be identified due to obscuration by adjacent vessels or due to low contrast between the lesion and background liver. It is important to remember that DWI combined with contrast-enhanced MRI has higher sensitivity than DWI alone, and that some patients are not eligible for use of contrast on CT and MRI; in these patients DWI has a prominent role. MRI has advanced beyond structural anatomic imaging to now showing pathophysiologic processes. DWI is a promising way to characterize lesions utilizing the inherent contrast within the liver and has the benefit of not requiring contrast injection. DWI improves detection and characterization of HCC. Proposed clinical uses for DWI include: assessing prognosis, predicting response, monitoring response to therapy, and distinguishing tumor recurrence from treatment effect. Ideally, DWI will help risk stratify patients and will participate in prognostic modeling. PMID:27471573

  17. MTF measurement and imaging quality evaluation of digital camera with slanted-edge method

    NASA Astrophysics Data System (ADS)

    Xiang, Chunchang; Chen, Xinhua; Chen, Yuheng; Zhou, Jiankang; Shen, Weimin

    2010-11-01

    Modulation Transfer Function (MTF) is the spatial frequency response of imaging systems and now develops as an objective merit performance for evaluating both quality of lens and camera. Slanted-edge method and its principle for measuring MTF of digital camera are introduced in this paper. The setup and software for testing digital camera is respectively established and developed. Measurement results with different tilt angle of the knife edge are compared to discuss the influence of the tilt angle. Also carefully denoise of the knife edge image is performed to decrease the noise sensitivity of knife edge measurement. Comparisons have been made between the testing results gained by slanted-edge method and grating target technique, and their deviation is analyzed.

  18. Diffusion-Weighted Magnetic Resonance Imaging in Monitoring Rectal Cancer Response to Neoadjuvant Chemoradiotherapy

    SciTech Connect

    Barbaro, Brunella; Vitale, Renata; Valentini, Vincenzo; Illuminati, Sonia; Vecchio, Fabio M.; Rizzo, Gianluca; Gambacorta, Maria Antonietta; Coco, Claudio; Crucitti, Antonio; Persiani, Roberto; Sofo, Luigi; Bonomo, Lorenzo

    2012-06-01

    Purpose: To prospectively monitor the response in patients with locally advanced nonmucinous rectal cancer after chemoradiotherapy (CRT) using diffusion-weighted magnetic resonance imaging. The histopathologic finding was the reference standard. Methods and Materials: The institutional review board approved the present study. A total of 62 patients (43 men and 19 women; mean age, 64 years; range, 28-83) provided informed consent. T{sub 2}- and diffusion-weighted magnetic resonance imaging scans (b value, 0 and 1,000 mm{sup 2}/s) were acquired before, during (mean 12 days), and 6-8 weeks after CRT. We compared the median apparent diffusion coefficients (ADCs) between responders and nonresponders and examined the associations with the Mandard tumor regression grade (TRG). The postoperative nodal status (ypN) was evaluated. The Mann-Whitney/Wilcoxon two-sample test was used to evaluate the relationships among the pretherapy ADCs, extramural vascular invasion, early percentage of increases in ADCs, and preoperative ADCs. Results: Low pretreatment ADCs (<1.0 Multiplication-Sign 10{sup -3}mm{sup 2}/s) were correlated with TRG 4 scores (p = .0011) and associated to extramural vascular invasion with ypN+ (85.7% positive predictive value for ypN+). During treatment, the mean percentage of increase in tumor ADC was significantly greater in the responders than in the nonresponders (p < .0001) and a >23% ADC increase had a 96.3% negative predictive value for TRG 4. In 9 of 16 complete responders, CRT-related tumor downsizing prevented ADC evaluations. The preoperative ADCs were significantly different (p = .0012) between the patients with and without downstaging (preoperative ADC {>=}1.4 Multiplication-Sign 10{sup -3}mm{sup 2}/s showed a positive and negative predictive value of 78.9% and 61.8%, respectively, for response assessment). The TRG 1 and TRG 2-4 groups were not significantly different. Conclusion: Diffusion-weighted magnetic resonance imaging seems to be a promising

  19. Developing tools for digital radar image data evaluation

    NASA Technical Reports Server (NTRS)

    Domik, G.; Leberl, F.; Raggam, J.

    1986-01-01

    The refinement of radar image analysis methods has led to a need for a systems approach to radar image processing software. Developments stimulated through satellite radar are combined with standard image processing techniques to create a user environment to manipulate and analyze airborne and satellite radar images. One aim is to create radar products for the user from the original data to enhance the ease of understanding the contents. The results are called secondary image products and derive from the original digital images. Another aim is to support interactive SAR image analysis. Software methods permit use of a digital height model to create ortho images, synthetic images, stereo-ortho images, radar maps or color combinations of different component products. Efforts are ongoing to integrate individual tools into a combined hardware/software environment for interactive radar image analysis.

  20. Video methods for evaluating physiologic monitor alarms and alarm responses.

    PubMed

    Bonafide, Christopher P; Zander, Miriam; Graham, Christian Sarkis; Weirich Paine, Christine M; Rock, Whitney; Rich, Andrew; Roberts, Kathryn E; Fortino, Margaret; Nadkarni, Vinay M; Lin, Richard; Keren, Ron

    2014-01-01

    False physiologic monitor alarms are extremely common in the hospital environment. High false alarm rates have the potential to lead to alarm fatigue, leading nurses to delay their responses to alarms, ignore alarms, or disable them entirely. Recent evidence from the U.S. Food and Drug Administration (FDA) and The Joint Commission has demonstrated a link between alarm fatigue and patient deaths. Yet, very little scientific effort has focused on the rigorous quantitative measurement of alarms and responses in the hospital setting. We developed a system using multiple temporarily mounted, minimally obtrusive video cameras in hospitalized patients' rooms to characterize physiologic monitor alarms and nurse responses as a proxy for alarm fatigue. This allowed us to efficiently categorize each alarm's cause, technical validity, actionable characteristics, and determine the nurse's response time. We describe and illustrate the methods we used to acquire the video, synchronize and process the video, manage the large digital files, integrate the video with data from the physiologic monitor alarm network, archive the video to secure servers, and perform expert review and annotation using alarm "bookmarks." We discuss the technical and logistical challenges we encountered, including the root causes of hardware failures as well as issues with consent, confidentiality, protection of the video from litigation, and Hawthorne-like effects. The description of this video method may be useful to multidisciplinary teams interested in evaluating physiologic monitor alarms and alarm responses to better characterize alarm fatigue and other patient safety issues in clinical settings. PMID:24847936

  1. Color image reproduction based on multispectral and multiprimary imaging: experimental evaluation

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Masahiro; Teraji, Taishi; Ohsawa, Kenro; Uchiyama, Toshio; Motomura, Hideto; Murakami, Yuri; Ohyama, Nagaaki

    2001-12-01

    Multispectral imaging is significant technology for the acquisition and display of accurate color information. Natural color reproduction under arbitrary illumination becomes possible using spectral information of both image and illumination light. In addition, multiprimary color display, i.e., using more than three primary colors, has been also developed for the reproduction of expanded color gamut, and for discounting observer metamerism. In this paper, we present the concept for the multispectral data interchange for natural color reproduction, and the experimental results using 16-band multispectral camera and 6-primary color display. In the experiment, the accuracy of color reproduction is evaluated in CIE (Delta) Ea*b* for both image capture and display systems. The average and maximum (Delta) Ea*b* = 1.0 and 2.1 in 16-band mutispectral camera system, using Macbeth 24 color patches. In the six-primary color projection display, average and maximum (Delta) Ea*b* = 1.3 and 2.7 with 30 test colors inside the display gamut. Moreover, the color reproduction results with different spectral distributions but same CIE tristimulus value are visually compared, and it is confirmed that the 6-primary display gives improved agreement between the original and reproduced colors.

  2. A no a priori knowledge estimation of the impulse response for satellite image noise reduction

    NASA Astrophysics Data System (ADS)

    Benbouzid, A. B.; Taleb, N.

    2015-04-01

    Due to launching vibrations and space harsh environment, high resolution remote sensing satellite imaging systems require permanent assessment and control of image quality, which may vary between ground pre-launch measurements, after launch and over satellite lifetime. In order to mitigate noise, remove artifacts and enhance image interpretability, the Point Spread Function (PSF) of the imaging system is estimated. Image deconvolution can be performed across the characterization of the actual Modulation Transfer Function (MTF) of the imaging system. In this work we focus on adapting and applying a no reference method to characterize in orbit high resolution satellite images in terms of geometrical performance. Moreover, we use natural details contained in images as edges transitions to estimate the impulse response via the assessment of the MTF image. The obtained results are encouraging and promising.

  3. Biomarkers and Molecular Imaging as Predictors of Response to Neoadjuvant Chemoradiotherapy in Patients With Locally Advanced Rectal Cancer.

    PubMed

    Molinari, Chiara; Matteucci, Federica; Caroli, Paola; Passardi, Alessandro

    2015-12-01

    Standard treatment of patients with locally advanced rectal cancer (LARC) includes neoadjuvant chemoradiotherapy (NCRT) followed by surgery. Tumor regression after NCRT varies substantially among individuals and pathological complete response is a known prognostic factor for LARC. The identification of a predictive model for response to chemoradiotherapy would help clinicians to identify patients who would probably benefit from multimodal treatment and to perform an early assessment of individual prognosis. Carcinoembryonic antigen has proven to be a good predictor of response in several clinical trials. Other widely studied predictive models in LARC include molecular biomarkers, analyzed at various levels and by different techniques, and molecular imaging, in particular magnetic resonance imaging and positron emission tomography/computed tomography. Although none of the studied markers have been approved in clinical practice, their evaluation in larger, prospective trials and in combined predictive models could be of use to define tailored therapeutic strategies. PMID:26170142

  4. A database system to support image algorithm evaluation

    NASA Technical Reports Server (NTRS)

    Lien, Y. E.

    1977-01-01

    The design is given of an interactive image database system IMDB, which allows the user to create, retrieve, store, display, and manipulate images through the facility of a high-level, interactive image query (IQ) language. The query language IQ permits the user to define false color functions, pixel value transformations, overlay functions, zoom functions, and windows. The user manipulates the images through generic functions. The user can direct images to display devices for visual and qualitative analysis. Image histograms and pixel value distributions can also be computed to obtain a quantitative analysis of images.

  5. Diffuse optical spectroscopic imaging correlates with final pathological response in breast cancer neoadjuvant chemotherapy

    PubMed Central

    Cerussi, Albert E.; Tanamai, Vaya W.; Hsiang, David; Butler, John; Mehta, Rita S.; Tromberg, Bruce J.

    2011-01-01

    Diffuse optical spectroscopic imaging (DOSI) non-invasively and quantitatively measures tissue haemoglobin, water and lipid. Pilot studies in small groups of patients demonstrate that DOSI may be useful for longitudinal monitoring and predicting breast cancer neoadjuvant chemotherapy pathological response. This study evaluates the performance of a bedside DOSI platform in 34 breast cancer patients followed for several months. DOSI optical endpoints obtained at multiple timepoints are compared with final pathological response. Thirty-six stage II/III breast cancers (34 patients) were measured in vivo with DOSI prior to, in the middle of and after the completion of pre-surgical neoadjuvant chemotherapy. Cancer therapies ranged from standard anthracyclines to targeted therapies. Changes in DOSI-measured parameters at each timepoint were compared against final surgical pathology. Absolute changes in the tumour-to-normal (T/N) ratio of tissue deoxyhaemoglobin concentration (ctHHb) and relative changes in the T/N ratio of a tissue optical index (TOI) were most sensitive and correlate to pathological response. Changes in ctHHb and TOI were significantly different between tumours that achieved pathological complete response (pCR) versus non-pCR. By therapy midpoint, mean TOI-T/N changes were 47±8 versus 20±5 per cent for pCR versus non-pCR subjects, respectively (Z=0.011). Changes in ctHHb and TOI scaled significantly with the degree of pathological response (non-, partial and complete). DOSI measurements of TOI separated pCR from non-pCR by therapy midpoint regardless of drug or dosing strategy. This approach is well suited to monitoring breast tumour response and may provide feedback for optimizing therapeutic outcomes and minimizing side-effects. PMID:22006904

  6. Translation of infrared chemical imaging for cardiovascular evaluation

    NASA Astrophysics Data System (ADS)

    Tiwari, Saumya; Raman, Jai; Reddy, Vijaya; Dawson, Miranda; Bhargava, Rohit

    2016-03-01

    Infrared (IR) spectroscopic imaging has been applied to study histology of cardiovascular tissue, primarily using Fourier transform IR (FTIR) Imaging. Here we describe results for histologic imaging of cardiac biopsies using a fast, discrete frequency IR (DFIR) imaging system. Histologic classification of tissue is understood in terms of the constituent frequencies and speeded up by careful optimization of the data acquired. Results are compared to FTIR imaging in terms of the signal to noise ratio and information content.

  7. Evaluation of musculoskeletal sepsis with indium-111 white blood cell imaging

    SciTech Connect

    Ouzounian, T.J.; Thompson, L.; Grogan, T.J.; Webber, M.M.; Amstutz, H.C.

    1987-08-01

    The detection of musculoskeletal sepsis, especially following joint replacement, continues to be a challenging problem. Often, even with invasive diagnostic evaluation, the diagnosis of infection remains uncertain. This is a report on the first 55 Indium-111 white blood cell (WBC) images performed in 39 patients for the evaluation of musculoskeletal sepsis. There were 40 negative and 15 positive Indium-111 WBC images. These were correlated with operative culture and tissue pathology, aspiration culture, and clinical findings. Thirty-eight images were performed for the evaluation of possible total joint sepsis (8 positive and 30 negative images); 17 for the evaluation of nonarthroplasty-related musculoskeletal sepsis (7 positive and 10 negative images). Overall, there were 13 true-positive, 39 true-negative, two false-positive, and one false-negative images. Indium-111 WBC imaging is a sensitive and specific means of evaluating musculoskeletal sepsis, especially following total joint replacement.

  8. Negative Stimulus-Response Compatibility Observed with a Briefly Displayed Image of a Hand

    ERIC Educational Resources Information Center

    Vainio, Lari

    2011-01-01

    Manual responses can be primed by viewing an image of a hand. The left-right identity of the viewed hand reflexively facilitates responses of the hand that corresponds to the identity. Previous research also suggests that when the response activation is triggered by an arrow, which is backward-masked and presented briefly, the activation manifests…

  9. Particle response analysis for particle image velocimetry in supersonic flows

    NASA Astrophysics Data System (ADS)

    Williams, Owen J. H.; Nguyen, Tue; Schreyer, Anne-Marie; Smits, Alexander J.

    2015-07-01

    We examine the effects of compressibility, slip, and fluid inertia on the frequency response of particle-based velocimetry techniques for supersonic and hypersonic flows by solving the quasi-steady drag equation for solid, spherical particles. We demonstrate that non-continuum and fluid inertial effects significantly affect the particle response under all typical supersonic flow conditions. In particular, the particle frequency response obtained from a shock response test depends on the strength of the shock, decreasing with shock strength as non-continuum effects become more prominent. For weak disturbances, such as those typical of turbulence, the actual particle frequency response can therefore be much lower than that obtained from a typical shock response. The greatest variability in the response was found to occur at low supersonic Mach numbers. The results were found to be typical of solid particles used for velocimetry under a wide range of wind tunnel conditions, and so, previous particle frequency response analyses based solely on shock response tests may well have overestimated the response to turbulence.

  10. Characteristics of Mindless Teaching Evaluations and the Moderating Effects of Image Compatibility.

    ERIC Educational Resources Information Center

    Dunegan, Kenneth J.; Hrivnak, Mary W.

    2003-01-01

    At 3 times, 164 management students completed student evaluations of teaching (SET), 150 completed an image compatibility questionnaire, and 155 evaluated instructors' overall performance. SET scores and overall evaluations were significantly correlated only when actual and ideal images of instructors were incompatible. When teaching was…

  11. Surface defect detection in tiling Industries using digital image processing methods: analysis and evaluation.

    PubMed

    Karimi, Mohammad H; Asemani, Davud

    2014-05-01

    Ceramic and tile industries should indispensably include a grading stage to quantify the quality of products. Actually, human control systems are often used for grading purposes. An automatic grading system is essential to enhance the quality control and marketing of the products. Since there generally exist six different types of defects originating from various stages of tile manufacturing lines with distinct textures and morphologies, many image processing techniques have been proposed for defect detection. In this paper, a survey has been made on the pattern recognition and image processing algorithms which have been used to detect surface defects. Each method appears to be limited for detecting some subgroup of defects. The detection techniques may be divided into three main groups: statistical pattern recognition, feature vector extraction and texture/image classification. The methods such as wavelet transform, filtering, morphology and contourlet transform are more effective for pre-processing tasks. Others including statistical methods, neural networks and model-based algorithms can be applied to extract the surface defects. Although, statistical methods are often appropriate for identification of large defects such as Spots, but techniques such as wavelet processing provide an acceptable response for detection of small defects such as Pinhole. A thorough survey is made in this paper on the existing algorithms in each subgroup. Also, the evaluation parameters are discussed including supervised and unsupervised parameters. Using various performance parameters, different defect detection algorithms are compared and evaluated. PMID:24502941

  12. Image deconvolution with multi-stage convex relaxation and its perceptual evaluation.

    PubMed

    Hou, Tingbo; Wang, Sen; Qin, Hong

    2011-12-01

    This paper proposes a new image deconvolution method using multi-stage convex relaxation, and presents a metric for perceptual evaluation of deconvolution results. Recent work in image deconvolution addresses the deconvolution problem via minimization with non-convex regularization. Since all regularization terms in the objective function are non-convex, this problem can be well modeled and solved by multi-stage convex relaxation. This method, adopted from machine learning, iteratively refines the convex relaxation formulation using concave duality. The newly proposed deconvolution method has outstanding performance in noise removal and artifact control. A new metric, transduced contrast-to-distortion ratio (TCDR), is proposed based on a human vision system (HVS) model that simulates human responses to visual contrasts. It is sensitive to ringing and boundary artifacts, and very efficient to compute. We conduct comprehensive perceptual evaluation of image deconvolution using visual signal-to-noise ratio (VSNR) and TCDR. Experimental results of both synthetic and real data demonstrate that our method indeed improves the visual quality of deconvolution results with low distortions and artifacts. PMID:21550886

  13. Aquifer imaging with pressure waves—Evaluation of low-impact characterization through sandbox experiments

    NASA Astrophysics Data System (ADS)

    Zhou, YaoQuan; Lim, David; Cupola, Fausto; Cardiff, Michael

    2016-03-01

    Understanding the detailed spatial variation of hydraulic properties in the subsurface has been the subject of intensive research over the past three decades. A recently developed approach to characterize subsurface properties is hydraulic tomography, in which a series of pumping tests are jointly inverted using a heterogeneous numerical model. Recently, Cardiff et al. (2013) proposed a modified tomography approach named Oscillatory Hydraulic Tomography (OHT), in which periodic pumping signals of different frequencies serve as the aquifer stimulation, and pressure responses are recorded at observation locations for tomographic analysis. Its key advantages over traditional hydraulic tomography are that: (1) there is no net injection or extraction of water, and (2) the impulse (an oscillatory signal of known frequency) is easily extracted from noisy data. However, OHT has only been evaluated through numerical experiments to date. In this work, we evaluate OHT performance by attempting to image known heterogeneities in a synthetic aquifer. An instrumented laboratory sandbox is filled with material of known hydraulic properties, and we measure aquifer responses due to oscillatory pumping stimulations at periods of 2, 5, 10, and 20 s. Pressure oscillation time series are processed through Fourier Transforms and inverted tomographically to obtain estimates of aquifer heterogeneity, using a fast, steady-periodic groundwater flow model. We show that OHT is able to provide robust estimates of aquifer hydraulic conductivity even in cases where relatively few pumping tests and observation locations are available. The use of multiple stimulation frequencies is also shown to improve imaging results.

  14. Development of a medical image filing system based on superhigh-definition image and its functional evaluation

    NASA Astrophysics Data System (ADS)

    Takeda, Hiroshi; Matsumura, Yasushi; Okada, Takeo; Kuwata, Shigeki; Wada, Minoru; Hashimoto, Tsutomu

    1997-05-01

    Although many images are handled in the medical filed, image monitoring deices and filing methods vary due to differences in resolution and pixel depth. If a system enabling such images to be filed synthetically without losing its quality were to exist, and if retrieval of such images were made easily, such a system could be applied in various ways. In order to determine whether a super high definition (SHD) image system running at a series of 2048 resolution X 2048 line X 60 frame/sec was capable of such purposes, we established a filing system for medical images on this system. All images of various types produced form one case of cardiovascular disease were digitized and registered into this filing system. Images consisted of plain chest x-ray, electrocardiogram, ultrasound cardiogram, cardiac scintigram, coronary angiogram, left ventriculogram and so on. All images were animated and totaled a number of 243. We prepared a graphic user interface for image retrieval based on the medical events and modalities. Twenty one cardiac specialists evaluated quality of the SHD images to be somewhat poor compared to the original pictures but sufficient for making diagnoses, and effective as a tool for teaching and case study group purposes because of its operability of the retrieval system. The system capability of simultaneously displaying several animated images was especially deemed effective in grasping comprehension of diagnosis. efficient input methods, and creating a capacity of filing all produced images are future issue.

  15. Assessing Combinational Drug Efficacy in Cancer Cells by Using Image-based Dynamic Response Analysis

    PubMed Central

    Sima, Chao; Hua, Jianping; Cypert, Milana; Miller, Tasha; Wilson-Robles, Heather M.; Trent, Jeffrey M.; Dougherty, Edward R.; Bittner, Michael L.

    2015-01-01

    The landscape of translational research has been shifting toward drug combination therapies. Pairing of drugs allows for more types of drug interaction with cells. In order to accurately and comprehensively assess combinational drug efficacy, analytical methods capable of recognizing these alternative reactions will be required to prioritize those drug candidates having better chances of delivering appreciable therapeutic benefits. Traditional efficacy measures are primarily based on the “extent” of drug inhibition, which is the percentage of cells being killed after drug exposure. Here, we introduce a second dimension of evaluation criterion, speed of killing, based on a live cell imaging assay. This dynamic response trajectory approach takes advantage of both “extent” and “speed” information and uncovers synergisms that would otherwise be missed, while also generating hypotheses regarding important mechanistic modes of drug action. PMID:26997864

  16. Using optical coherence tomography (OCT) imaging in the evaluation of airway dynamics (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Szabari, Margit V.; Kelly, Vanessa J.; Applegate, Matthew B.; Chee, Chunmin; Tan, Khay M.; Hariri, Lida P.; Harris, R. Scott; Winkler, Tilo; Suter, Melissa J.

    2016-03-01

    Asthma is a chronic disease resulting in periodic attacks of coughing and wheezing due to temporarily constricted and clogged airways. The pathophysiology of asthma and the process of airway narrowing are not completely understood. Appropriate in vivo imaging modality with sufficient spatial and temporal resolution to dynamically assess the behavior of airways is missing. Optical coherence tomography (OCT) enables real-time evaluation of the airways during dynamic and static breathing maneuvers. Our aim was to visualize the structure and function of airways in healthy and Methacholine (MCh) challenged lung. Sheep (n=3) were anesthetized, mechanically ventilated and imaged with OCT in 4 dependent and 4 independent airways both pre- and post-MCh administration. The OCT system employed a 2.4 Fr (0.8 mm diameter) catheter and acquired circumferential cross-sectional images in excess of 100 frames per second during dynamic tidal breathing, 20 second static breath-holds at end-inspiration and expiration pressure, and in a response to a single deep inhalation. Markedly different airway behavior was found in dependent versus non-dependent airway segments before and after MCh injection. OCT is a non-ionizing light-based imaging modality, which may provide valuable insight into the complex dynamic behavior of airway structure and function in the normal and asthmatic lung.

  17. Non-invasive in vivo imaging of early metabolic tumor response to therapies targeting choline metabolism.

    PubMed

    Mignion, Lionel; Danhier, Pierre; Magat, Julie; Porporato, Paolo E; Masquelier, Julien; Gregoire, Vincent; Muccioli, Giulio G; Sonveaux, Pierre; Gallez, Bernard; Jordan, Bénédicte F

    2016-04-15

    The cholinic phenotype, characterized by elevated phosphocholine and a high production of total-choline (tCho)-containing metabolites, is a metabolic hallmark of cancer. It can be exploited for targeted therapy. Non-invasive imaging biomarkers are required to evaluate an individual's response to targeted anticancer agents that usually do not rapidly cause tumor shrinkage. Because metabolic changes can manifest at earlier stages of therapy than changes in tumor size, the aim of the current study was to evaluate (1)H-MRS and diffusion-weighted MRI (DW-MRI) as markers of tumor response to the modulation of the choline pathway in mammary tumor xenografts. Inhibition of choline kinase activity was achieved with the direct pharmacological inhibitor H-89, indirect inhibitor sorafenib and down-regulation of choline-kinase α (ChKA) expression using specific short-hairpin RNA (shRNA). While all three strategies significantly decreased tCho tumor content in vivo, only sorafenib and anti-ChKA shRNA significantly repressed tumor growth. The increase of apparent-diffusion-coefficient of water (ADCw) measured by DW-MRI, was predictive of the induced necrosis and inhibition of the tumor growth in sorafenib treated mice, while the absence of change in ADC values in H89 treated mice predicted the absence of effect in terms of tumor necrosis and tumor growth. In conclusion, (1)H-choline spectroscopy can be useful as a pharmacodynamic biomarker for choline targeted agents, while DW-MRI can be used as an early marker of effective tumor response to choline targeted therapies. DW-MRI combined to choline spectroscopy may provide a useful non-invasive marker for the early clinical assessment of tumor response to therapies targeting choline signaling. PMID:26595604

  18. Fluorescence imaging of endothelial cellular responses in the intact lung microvasculature

    NASA Astrophysics Data System (ADS)

    Kuebler, Wolfgang M.; Brueckl, Corinna; Kuehnl, Andreas; Ying, Xiaoyou; Bhattacharya, Jahar

    2001-05-01

    Endothelial cells outline the blood vessel wall and contribute pivotally to the regulation of numerous microvascular characteristics such as permeability, vascular tone, vasomotion, or cell-cell interactions. These functions are mediated by second messenger responses and intracellular signal transduction cascades within the endothelial cells. Imaging of endothelial cellular and subcellular responses has yet been limited to studies in isolated or cultured cells, which cannot reflect dynamic physiologic or pathologic cellular interactions in the intact microcirculation. Combining micropuncture and microcatheter approaches with in vitro fluorescence imaging techniques, we have developed methods for imaging endothelial cellular responses of intact pulmonary microvessels in situ.

  19. Voxelwise single-subject analysis of imaging metabolic response to therapy in neuro-oncology.

    PubMed

    Guo, Mengye; Yap, Jeffrey T; Van den Abbeele, Annick D; Lin, Nancy U; Schwartzman, Armin

    2014-01-01

    F-18-Fluorodeoxyglucose positron emission tomography (FDG-PET) has been used to evaluate the metabolic response of metastatic brain tumors to treatment by comparing their tumor glucose metabolism before and after treatment. The standard analysis based on regions-of-interest has the advantage of simplicity. However, it is by definition restricted to those regions and is subject to observer variability. In addition, the observed changes in tumor metabolism are often confounded by normal changes in the tissue background, which can be heterogenous. We propose an analysis pipeline for automatically detecting the change at each voxel in the entire brain of a single subject, while adjusting for changes in the background. The complete analysis includes image registration, segmentation, a hierarchical model for background adjustment and voxelwise statistical comparisons. We demonstrate the method's ability to identify areas of tumor response and/or progression in two subjects enrolled in a clinical trial using FDG-PET to evaluate lapatinib for the treatment of brain metastases in breast cancer patients. PMID:24999285

  20. Cancer Education Program Evaluation: A Responsive Approach to Planning an Evaluation and Initial Results.

    ERIC Educational Resources Information Center

    Pearsol, James A.

    This paper describes evaluation planning for the Cancer Education Program (CEP) at Ohio State University (OSU). The three-year OSU CEP project was designed as a multidisciplinary cancer education program. A responsive method, which trades off some measurement precision in order to increase the usefulness of the findings, was employed in the…

  1. Spectral CT Imaging of Laryngeal and Hypopharyngeal Squamous Cell Carcinoma: Evaluation of Image Quality and Status of Lymph Nodes

    PubMed Central

    Li, Wei; Wang, Zhongzhou; Pang, Tao; Li, Jun; Shi, Hao; Zhang, Chengqi

    2013-01-01

    Purpose The purpose of this study was to evaluate image quality and status of lymph nodes in laryngeal and hypopharyngeal squamous cell carcinoma (SCC) patients using spectral CT imaging. Materials and Methods Thirty-eight patients with laryngeal and hypopharyngeal SCCs were scanned with spectral CT mode in venous phase. The conventional 140-kVp polychromatic images and one hundred and one sets of monochromatic images were generated ranging from 40 keV to 140 keV. The mean optimal keV was calculated on the monochromatic images. The image quality of the mean optimal keV monochromatic images and polychromatic images was compared with two different methods including a quantitative analysis method and a qualitative analysis method. The HU curve slope (λHU) in the target lymph nodes and the primary lesion was calculated respectively. The ratio of λHU was studied between metastatic and non-metastatic lymph nodes group. Results A total of 38 primary lesions were included. The mean optimal keV was obtained at 55±1.77 keV on the monochromatic images. The image quality evaluated by two different methods including a quantitative analysis method and a qualitative analysis method was obviously increased on monochromatic images than polychromatic images (p<0.05). The ratio of λHU between metastatic and non-metastatic lymph nodes was significantly different in the venous phase images (p<0.05). Conclusion The monochromatic images obtained with spectral CT can be used to improve the image quality of laryngeal and hypopharyngeal SCC and the N-staging accuracy. The quantitative ratio of λHU may be helpful for differentiating between metastatic and non-metastatic cervical lymph nodes. PMID:24386214

  2. Probability effects on stimulus evaluation and response processes

    NASA Technical Reports Server (NTRS)

    Gehring, W. J.; Gratton, G.; Coles, M. G.; Donchin, E.

    1992-01-01

    This study investigated the effects of probability information on response preparation and stimulus evaluation. Eight subjects responded with one hand to the target letter H and with the other to the target letter S. The target letter was surrounded by noise letters that were either the same as or different from the target letter. In 2 conditions, the targets were preceded by a warning stimulus unrelated to the target letter. In 2 other conditions, a warning letter predicted that the same letter or the opposite letter would appear as the imperative stimulus with .80 probability. Correct reaction times were faster and error rates were lower when imperative stimuli confirmed the predictions of the warning stimulus. Probability information affected (a) the preparation of motor responses during the foreperiod, (b) the development of expectancies for a particular target letter, and (c) a process sensitive to the identities of letter stimuli but not to their locations.

  3. Prognostication and response assessment in liver and pancreatic tumors: The new imaging.

    PubMed

    De Robertis, Riccardo; Tinazzi Martini, Paolo; Demozzi, Emanuele; Puntel, Gino; Ortolani, Silvia; Cingarlini, Sara; Ruzzenente, Andrea; Guglielmi, Alfredo; Tortora, Giampaolo; Bassi, Claudio; Pederzoli, Paolo; D'Onofrio, Mirko

    2015-06-14

    Diffusion-weighted imaging (DWI), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and perfusion computed tomography (CT) are technical improvements of morphologic imaging that can evaluate functional properties of hepato-bilio-pancreatic tumors during conventional MRI or CT examinations. Nevertheless, the term "functional imaging" is commonly used to describe molecular imaging techniques, as positron emission tomography (PET) CT/MRI, which still represent the most widely used methods for the evaluation of functional properties of solid neoplasms; unlike PET or single photon emission computed tomography, functional imaging techniques applied to conventional MRI/CT examinations do not require the administration of radiolabeled drugs or specific equipments. Moreover, DWI and DCE-MRI can be performed during the same session, thus providing a comprehensive "one-step" morphological and functional evaluation of hepato-bilio-pancreatic tumors. Literature data reveal that functional imaging techniques could be proposed for the evaluation of these tumors before treatment, given that they may improve staging and predict prognosis or clinical outcome. Microscopic changes within neoplastic tissues induced by treatments can be detected and quantified with functional imaging, therefore these techniques could be used also for post-treatment assessment, even at an early stage. The aim of this editorial is to describe possible applications of new functional imaging techniques apart from molecular imaging to hepatic and pancreatic tumors through a review of up-to-date literature data, with a particular emphasis on pathological correlations, prognostic stratification and post-treatment monitoring. PMID:26078555

  4. A quantitative evaluation of the public response to climate engineering

    NASA Astrophysics Data System (ADS)

    Wright, Malcolm J.; Teagle, Damon A. H.; Feetham, Pamela M.

    2014-02-01

    Atmospheric greenhouse gas concentrations continue to increase, with CO2 passing 400 parts per million in May 2013. To avoid severe climate change and the attendant economic and social dislocation, existing energy efficiency and emissions control initiatives may need support from some form of climate engineering. As climate engineering will be controversial, there is a pressing need to inform the public and understand their concerns before policy decisions are taken. So far, engagement has been exploratory, small-scale or technique-specific. We depart from past research to draw on the associative methods used by corporations to evaluate brands. A systematic, quantitative and comparative approach for evaluating public reaction to climate engineering is developed. Its application reveals that the overall public evaluation of climate engineering is negative. Where there are positive associations they favour carbon dioxide removal (CDR) over solar radiation management (SRM) techniques. Therefore, as SRM techniques become more widely known they are more likely to elicit negative reactions. Two climate engineering techniques, enhanced weathering and cloud brightening, have indistinct concept images and so are less likely to draw public attention than other CDR or SRM techniques.

  5. Susceptibility weighted imaging of stroke brain in response to normobaric oxygen (NBO) therapy

    NASA Astrophysics Data System (ADS)

    Zhou, Iris Y.; Igarashi, Takahiro; Guo, Yingkun; Sun, Phillip Z.

    2015-03-01

    The neuroprotective effect of oxygen leads to recent interest in normobaric oxygen (NBO) therapy after acute ischemic stroke. However, the mechanism remains unclear and inconsistent outcomes were reported in human studies. Because NBO aims to improve brain tissue oxygenation by enhancing oxygen delivery to ischemic tissue, monitoring the oxygenation level changes in response to NBO becomes necessary to elucidate the mechanism and to assess the efficacy. Susceptibility weighted imaging (SWI) which provides a new MRI contrast by combining the magnitude and phase images is fit for purpose. SWI is sensitive to deoxyhemoglobin level changes and thus can be used to evaluate the cerebral metabolic rate of oxygen. In this study, SWI was used for in vivo monitoring of oxygenation changes in a rat model of permanent middle cerebral artery occlusion (MCAO) before, during and after 30 min of NBO treatment. Regions of interest in ischemic core, penumbra and contralateral normal area were generated based on diffusionweighted imaging and perfusion imaging. Significant differences in SWI indicating different oxygenation levels were generally found: contralateral normal > penumbra > ischemic core. Ischemic core showed insignificant increase in oxygenation during NBO and returned to pre-treatment level after termination of NBO. Meanwhile, the oxygenation levels slightly increased in contralateral normal and penumbra regions during NBO and significantly decreased to a level lower than pre-treatment after termination of NBO, indicating secondary metabolic disruption upon the termination of transient metabolic support from oxygen. Further investigation of NBO effect combined with reperfusion is necessary while SWI can be used to detect hemorrhagic transformation after reperfusion.

  6. Body-Image Evaluation and Body-Image Investment among Adolescents: A Test of Sociocultural and Social Comparison Theories

    ERIC Educational Resources Information Center

    Morrison, Todd G.; Kalin, Rudolf; Morrison, Melanie A.

    2004-01-01

    Sociocultural theory and social comparison theory were used to account for variations in body-image evaluation and body-image investment among male and female adolescents (N = 1,543). Exposure to magazines and television programs containing idealistic body imagery as well as frequency of self-comparison to universalistic targets (e.g., fashion…

  7. Evaluating structural deterioration of ceramic candle filters using dynamic response

    SciTech Connect

    Chen, R.H.L.; Parthasarathy, B.

    1996-12-31

    Ceramic candle filters used in the recent demonstration plant have experienced degradation and fracturing. Preliminary examination of these ceramic filters indicated that damage of the filters may have resulted from strength degradation. This study proposes a nondestructive evaluation of the structural properties of the ceramic candle filters. A virgin Refraction filter and twelve Schumacher filters which were previously tested under high pressure and high temperature at the demonstration power plant were evaluated. The vibration signatures of the ceramic filters at different degradation levels are established using transient impact response technique. Results from this study indicate that the natural frequencies of the filters can be used as an index to quantify the damage condition of the filters. The results of this study also indicate the feasibility of using the vibration mode shapes to predict the damage location of the filters.

  8. Volumetric breast density evaluation from ultrasound tomography images

    SciTech Connect

    Glide-Hurst, Carri K.; Duric, Neb; Littrup, Peter

    2008-09-15

    Previous ultrasound tomography work conducted by our group showed a direct correlation between measured sound speed and physical density in vitro, and increased in vivo sound speed with increasing mammographic density, a known risk factor for breast cancer. Building on these empirical results, the purpose of this work was to explore a metric to quantify breast density using our ultrasound tomography sound speed images in a manner analogous to computer-assisted mammogram segmentation for breast density analysis. Therefore, volumetric ultrasound percent density (USPD) is determined by segmenting high sound speed areas from each tomogram using a k-means clustering routine, integrating these results over the entire volume of the breast, and dividing by whole-breast volume. First, a breast phantom comprised of fat inclusions embedded in fibroglandular tissue was scanned four times with both our ultrasound tomography clinical prototype (with 4 mm spatial resolution) and CT. The coronal transmission tomograms and CT images were analyzed using semiautomatic segmentation routines, and the integrated areas of the phantom's fat inclusions were compared between the four repeated scans. The average variability for inclusion segmentation was {approx}7% and {approx}2%, respectively, and a close correlation was observed in the integrated areas between the two modalities. Next, a cohort of 93 patients was imaged, yielding volumetric coverage of the breast (45-75 sound speed tomograms/patient). The association of USPD with mammographic percent density (MPD) was evaluated using two measures: (1) qualitative, as determined by a radiologist's visual assessment using BI-RADS Criteria and (2) quantitative, via digitization and semiautomatic segmentation of craniocaudal and mediolateral oblique mammograms. A strong positive association between BI-RADS category and USPD was demonstrated [Spearman {rho}=0.69 (p<0.001)], with significant differences between all BI-RADS categories as assessed

  9. Acquisition and Analysis of Dynamic Responses of a Historic Pedestrian Bridge using Video Image Processing

    NASA Astrophysics Data System (ADS)

    O'Byrne, Michael; Ghosh, Bidisha; Schoefs, Franck; O'Donnell, Deirdre; Wright, Robert; Pakrashi, Vikram

    2015-07-01

    Video based tracking is capable of analysing bridge vibrations that are characterised by large amplitudes and low frequencies. This paper presents the use of video images and associated image processing techniques to obtain the dynamic response of a pedestrian suspension bridge in Cork, Ireland. This historic structure is one of the four suspension bridges in Ireland and is notable for its dynamic nature. A video camera is mounted on the river-bank and the dynamic responses of the bridge have been measured from the video images. The dynamic response is assessed without the need of a reflector on the bridge and in the presence of various forms of luminous complexities in the video image scenes. Vertical deformations of the bridge were measured in this regard. The video image tracking for the measurement of dynamic responses of the bridge were based on correlating patches in time-lagged scenes in video images and utilisinga zero mean normalised cross correlation (ZNCC) metric. The bridge was excited by designed pedestrian movement and by individual cyclists traversing the bridge. The time series data of dynamic displacement responses of the bridge were analysedto obtain the frequency domain response. Frequencies obtained from video analysis were checked against accelerometer data from the bridge obtained while carrying out the same set of experiments used for video image based recognition.

  10. Acquisition and Analysis of Dynamic Responses of a Historic Pedestrian Bridge using Video Image Processing

    NASA Astrophysics Data System (ADS)

    O'Byrne, Michael; Ghosh, Bidisha; Schoefs, Franck; O'Donnell, Deirdre; Wright, Robert; Pakrashi, Vikram

    2015-07-01

    Video based tracking is capable of analysing bridge vibrations that are characterised by large amplitudes and low frequencies. This paper presents the use of video images and associated image processing techniques to obtain the dynamic response of a pedestrian suspension bridge in Cork, Ireland. This historic structure is one of the four suspension bridges in Ireland and is notable for its dynamic nature. A video camera is mounted on the river-bank and the dynamic responses of the bridge have been measured from the video images. The dynamic response is assessed without the need of a reflector on the bridge and in the presence of various forms of luminous complexities in the video image scenes. Vertical deformations of the bridge were measured in this regard. The video image tracking for the measurement of dynamic responses of the bridge were based on correlating patches in time-lagged scenes in video images and utilisinga zero mean normalisedcross correlation (ZNCC) metric. The bridge was excited by designed pedestrian movement and by individual cyclists traversing the bridge. The time series data of dynamic displacement responses of the bridge were analysedto obtain the frequency domain response. Frequencies obtained from video analysis were checked against accelerometer data from the bridge obtained while carrying out the same set of experiments used for video image based recognition.

  11. Requirement for measurement of accommodation response based image blur due to the integral photography

    NASA Astrophysics Data System (ADS)

    Yano, Sumio; Imai, Hiromichi; Park, Min-Chul

    2016-06-01

    In the first part of this paper, the principle and the development of IP display using computer software were described. Next, the measurement results of accommodation response for the developed IP display were described. As a result, the accommodation response was linearly changed as the depth position of the visual target moved in and out of the range of the depth of focus. On the other hand, the influences generated by the image blur for the accommodation response were investigated experimentally using stereoscopic images. The results showed that the accommodation response was coincident to the convergence point of stereoscopic images with less than 3 cpd spatial resolution. Based on these results, the considerations of the measurement results of the accommodation response for the development IP were examined. The requirements of the measurement condition of accommodation response for IP were also discussed.

  12. [Role and responsibility of multimodal imaging in head and neck cancer].

    PubMed

    Gõdény, Mária

    2013-09-01

    Hungary is first in head and neck cancer mortality in Europe in men and also in women. Head and neck (HN) is a difficult region, its anatomy and also pathology is very complex, various connection points exist between the sites which determine the extension of the disease. Diagnostic algorithms as well as imaging techniques have to be optimized to examine in standard manner. Like most other cancers, prognosis depends largely on the stage of the tumor. Accuracy of tumor detection and evaluation is very important because it affects treatment planning. As non-surgical organ-preserving therapeutic modalities (chemotherapy, chemoradiotherapy, targeted biological therapy) gain general acceptance, the importance of noninvasive diagnostic accuracy as well as radiologic evaluation of the extent of the tumor has increased. Clinical examinations including endoscopy should be combined with radiologic imaging to assess the precise local (T), regional nodal (N), and distant (M) extent of the tumor. Computed tomography (CT) and magnetic resonance imaging (MRI) have become basic tools in the diagnosis of head and neck tumors. They are both useful for assessing deep tumor extensions, able to detect changes missed by endoscopy. It has been shown that the primary determined tumor stage increases in up to 90% of patients after the results of cross sectional imaging. MRI is being increasingly used and has become the gold standard in head and neck cancer for staging, assessing tumor response, finding recurrent tumor and also for treatment planning in radiotherapy. The field strength of MRI scanners has been increasing to 1.5 T and now 3 T with better signal-to-noise ratio, higher resolution images and better tissue diagnosis. Functional MR techniques such as dynamic contrast enhanced MRI (DCE-MRI) and diffusion weighted MRI (DW-MRI) may provide further characterization. PET/CT is beneficial in detecting unsuspected metastatic nodes, distant disease and second primary tumor. PET/CT and

  13. The Role of Diffusion-Weighted Imaging (DWI) in Locoregional Therapy Outcome Prediction and Response Assessment for Hepatocellular Carcinoma (HCC): The New Era of Functional Imaging Biomarkers.

    PubMed

    Ludwig, Johannes M; Camacho, Juan C; Kokabi, Nima; Xing, Minzhi; Kim, Hyun S

    2015-01-01

    Reliable response criteria are critical for the evaluation of therapeutic response in hepatocellular carcinoma (HCC). Current response assessment is mainly based on: (1) changes in size, which is at times unreliable and lag behind the result of therapy; and (2) contrast enhancement, which can be difficult to quantify in the presence of benign post-procedural changes and in tumors presenting with a heterogeneous pattern of enhancement. Given these challenges, functional magnetic resonance imaging (MRI) techniques, such as diffusion-weighted imaging (DWI) have been recently investigated, aiding specificity to locoregional therapy response assessment and outcome prediction. Briefly, DWI quantifies diffusion of water occurring naturally at a cellular level (Brownian movement), which is restricted in multiple neoplasms because of high cellularity. Disruption of cellular integrity secondary to therapy results in increased water diffusion across the injured membranes. This review will provide an overview of the current literature on DWI therapy response assessment and outcome prediction in HCC following treatment with locoregional therapies. PMID:26854170

  14. The Role of Diffusion-Weighted Imaging (DWI) in Locoregional Therapy Outcome Prediction and Response Assessment for Hepatocellular Carcinoma (HCC): The New Era of Functional Imaging Biomarkers

    PubMed Central

    Ludwig, Johannes M.; Camacho, Juan C.; Kokabi, Nima; Xing, Minzhi; Kim, Hyun S.

    2015-01-01

    Reliable response criteria are critical for the evaluation of therapeutic response in hepatocellular carcinoma (HCC). Current response assessment is mainly based on: (1) changes in size, which is at times unreliable and lag behind the result of therapy; and (2) contrast enhancement, which can be difficult to quantify in the presence of benign post-procedural changes and in tumors presenting with a heterogeneous pattern of enhancement. Given these challenges, functional magnetic resonance imaging (MRI) techniques, such as diffusion-weighted imaging (DWI) have been recently investigated, aiding specificity to locoregional therapy response assessment and outcome prediction. Briefly, DWI quantifies diffusion of water occurring naturally at a cellular level (Brownian movement), which is restricted in multiple neoplasms because of high cellularity. Disruption of cellular integrity secondary to therapy results in increased water diffusion across the injured membranes. This review will provide an overview of the current literature on DWI therapy response assessment and outcome prediction in HCC following treatment with locoregional therapies. PMID:26854170

  15. Performance evaluation of image enhancement methods for objects detection and recognition

    NASA Astrophysics Data System (ADS)

    Cai, Tiefeng; Zhu, Feng; Hao, Yingming; Fan, Xiaopeng

    2015-10-01

    Human eyes cannot notice low contrast objects in the image. Image contrast enhancement methods can make the unnoticed objects noticed, and human can detect and recognize the objects. In order to guide the design of enhancement methods, performance of enhancement methods for objects detection and recognition(ODR) should be valued. The existing performance evaluation methods evaluate image enhancement methods by calculating the increment of contrast or image information entropy. However, it is essentially an image information transmission process that human detect and recognize objects in the image, and image contrast enhancement can be viewed as a form of image coding. According to human visual properties, the transmission process of ODR information are modeled in this paper, and a performance evaluation method was proposed from the information theory of Shannon.

  16. Response trajectories reveal conflict phase in image-word mismatch.

    PubMed

    van Vugt, Floris T; Cavanagh, Patrick

    2012-02-01

    In the present study, response trajectories were used in a picture–word conflict task to determine the timing of intermediate processing stages that are relatively inaccessible to response time measures. A marker was placed above or below the word ABOVE or BELOW so that its location was congruent or in conflict with the word's meaning. To report either word location(above or below the marker) or word meaning, participants moved a mouse upward toward the appropriate top left or right answer corner on the display screen.Their response trajectories showed a number of distinctive features: First, at about 200 ms after stimulus onset(the "decision moment"), the trajectory abruptly began to arc toward the appropriate answer corner; second,when the word's meaning and position were in conflict,the trajectory showed an interruption that continued until the conflict was resolved. By varying the SOA of the word and marker onsets, we found that the word meaning and word position became available at approximately 325 ms and 251 ms, respectively, after their onsets, and that the delay to resolve conflicts was about 138 ms. The timing of these response trajectory events was more stable than any extracted from the final response times, demonstrating the power of response trajectories to reveal processing stages that are only poorly resolved, if at all, by response time measures [added]. PMID:22219088

  17. Nietzschean Images of Self-Overcoming: Response to Rosenow.

    ERIC Educational Resources Information Center

    Hillesheim, James W.

    1990-01-01

    Discusses interpretations of a key Nietzschean concept, "Selbstuberwindung," translated as "self-overcoming," which challenges the concept of "self-mastery" or "self-control" found in traditional educational thought. Also discussed is Nietzsche's construction of images of self-overcoming individuals, examples designed to stimulate the process of…

  18. High responsivity CMOS imager pixel implemented in SOI technology

    NASA Technical Reports Server (NTRS)

    Zheng, X.; Wrigley, C.; Yang, G.; Pain, B.

    2000-01-01

    Availability of mature sub-micron CMOS technology and the advent of the new low noise active pixel sensor (APS) concept have enabled the development of low power, miniature, single-chip, CMOS digital imagers in the decade of the 1990's.

  19. Radiopacity Evaluation of Contemporary Luting Cements by Digitization of Images

    PubMed Central

    Reis, José Maurício dos Santos Nunes; Jorge, Érica Gouveia; Ribeiro, João Gustavo Rabelo; Pinelli, Ligia Antunes Pereira; Abi-Rached, Filipe de Oliveira; Tanomaru-Filho, Mário

    2012-01-01

    Objective. The aim of this study was to evaluate the radiopacity of two conventional cements (Zinc Cement and Ketac Cem Easymix), one resin-modified glass ionomer cement (RelyX Luting 2) and six resin cements (Multilink, Bistite II DC, RelyX ARC, Fill Magic Dual Cement, Enforce and Panavia F) by digitization of images. Methods. Five disc-shaped specimens (10 × 1.0 mm) were made for each material, according to ISO 4049. After setting of the cements, radiographs were made using occlusal films and a graduated aluminum stepwedge varying from 1.0 to 16 mm in thickness. The radiographs were digitized, and the radiopacity of the cements was compared with the aluminum stepwedge using the software VIXWIN-2000. Data (mmAl) were submitted to one-way ANOVA and Tukey's test (α = 0.05). Results. The Zinc Cement was the most radiopaque material tested (P < 0.05). The resin cements presented higher radiopacity (P < 0.05) than the conventional (Ketac Cem Easymix) or resin-modified glass ionomer (RelyX Luting 2) cements, except for the Fill Magic Dual Cement and Enforce. The Multilink presented the highest radiopacity (P < 0.05) among the resin cements. Conclusion. The glass ionomer-based cements (Ketac Cem Easymix and RelyX Luting 2) and the resin cements (Fill Magic Dual Cement and Enforce) showed lower radiopacity values than the minimum recommended by the ISO standard. PMID:23008777

  20. Radiopacity evaluation of contemporary resin composites by digitization of images

    PubMed Central

    Ermis, R. Banu; Yildirim, Derya; Yildiz, Gul; Gormez, Ozlem

    2014-01-01

    Objective: The aim of this study was to evaluate the radiopacity of different composite resins and compare the values to those of human enamel and dentine. Materials and Methods: Five specimens of each material with thicknesses of 2 mm were prepared and radiographed alongside aluminum step wedge and human enamel and dentin. Three occlusal radiographs for each material were taken and digitized using a desktop scanner. Mean gray values of the test materials were measured using Image J software. Then a conversion was performed according to establish the radiopacity of the test materials, in millimeters of equivalent Al. Data were analyzed using one-way analysis of variance and Duncan multiple range tests (P < 0.05). Results: The radiopacity values varied among the restorative materials (P < 0.05). The radiopacity values of the materials tested were, in decreasing order: Enamel Plus HRI > Z250 > Filtek Ultimate ≥ Z550 > Nexcomp ≥ Nanoceram Bright > enamel ≥ Estelite Sigma Quick > Clearfil Majesty Esthetic ≥ Reflexions XLS ≥ Aelite LS Posterior ≥ dentin ≥ 2 mm Al. Conclusion: All resin composite materials investigated in this study presented different radiopacity values. However, all materials had radiopacity values greater than dentin and had sufficient radiopacity to meet International Organization for Standardization 4049 standard. PMID:25202214

  1. No-reference remote sensing image quality assessment using a comprehensive evaluation factor

    NASA Astrophysics Data System (ADS)

    Wang, Lin; Wang, Xu; Li, Xiao; Shao, Xiaopeng

    2014-05-01

    The conventional image quality assessment algorithm, such as Peak Signal to Noise Ratio (PSNR), Mean Square Error(MSE) and structural similarity (SSIM), needs the original image as a reference. It's not applicable to the remote sensing image for which the original image cannot be assumed to be available. In this paper, a No-reference Image Quality Assessment (NRIQA) algorithm is presented to evaluate the quality of remote sensing image. Since blur and noise (including the stripe noise) are the common distortion factors affecting remote sensing image quality, a comprehensive evaluation factor is modeled to assess the blur and noise by analyzing the image visual properties for different incentives combined with SSIM based on human visual system (HVS), and also to assess the stripe noise by using Phase Congruency (PC). The experiment results show this algorithm is an accurate and reliable method for Remote Sensing Image Quality Assessment.

  2. Prognostication and response assessment in liver and pancreatic tumors: The new imaging

    PubMed Central

    De Robertis, Riccardo; Tinazzi Martini, Paolo; Demozzi, Emanuele; Puntel, Gino; Ortolani, Silvia; Cingarlini, Sara; Ruzzenente, Andrea; Guglielmi, Alfredo; Tortora, Giampaolo; Bassi, Claudio; Pederzoli, Paolo; D’Onofrio, Mirko

    2015-01-01

    Diffusion-weighted imaging (DWI), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and perfusion computed tomography (CT) are technical improvements of morphologic imaging that can evaluate functional properties of hepato-bilio-pancreatic tumors during conventional MRI or CT examinations. Nevertheless, the term “functional imaging” is commonly used to describe molecular imaging techniques, as positron emission tomography (PET) CT/MRI, which still represent the most widely used methods for the evaluation of functional properties of solid neoplasms; unlike PET or single photon emission computed tomography, functional imaging techniques applied to conventional MRI/CT examinations do not require the administration of radiolabeled drugs or specific equipments. Moreover, DWI and DCE-MRI can be performed during the same session, thus providing a comprehensive “one-step” morphological and functional evaluation of hepato-bilio-pancreatic tumors. Literature data reveal that functional imaging techniques could be proposed for the evaluation of these tumors before treatment, given that they may improve staging and predict prognosis or clinical outcome. Microscopic changes within neoplastic tissues induced by treatments can be detected and quantified with functional imaging, therefore these techniques could be used also for post-treatment assessment, even at an early stage. The aim of this editorial is to describe possible applications of new functional imaging techniques apart from molecular imaging to hepatic and pancreatic tumors through a review of up-to-date literature data, with a particular emphasis on pathological correlations, prognostic stratification and post-treatment monitoring. PMID:26078555

  3. A reference data set for the evaluation of medical image retrieval systems.

    PubMed

    Müller, Henning; Rosset, Antoine; Vallée, Jean-Paul; Terrier, François; Geissbuhler, Antoine

    2004-09-01

    Content-based image retrieval is starting to become an increasingly important factor in medical imaging research and image management systems. Several retrieval systems and methodologies exist and are used in a large variety of applications from automatic labelling of images to diagnostic aid and image classification. Still, it is very hard to compare the performance of these systems as the used databases often contain copyrighted or private images and are thus not interchangeable between research groups, also for patient privacy. Most of the currently used databases for evaluating systems are also fairly small which is partly due to the high cost in obtaining a gold standard or ground truth that is necessary for evaluation. Several large image databases, though without a gold standard, start to be available publicly, for example by the NIH (National Institutes for Health). This article describes the creation of a large medical image database that is used in a teaching file containing more than 8,700 varied medical images. The images are anonymised and can be exchanged free of charge and copyright. Ground truth (a gold standard) has been obtained for a set of 26 images being selected as query topics for content-based query by image example. To reduce the time for the generation of ground truth, pooling methods well known from the text or information retrieval field have been used. Such a database is a good starting point for comparing the current image retrieval systems and to measure the retrieval quality, especially within the context of teaching files, image case databases and the support of teaching. For a comparison of retrieval systems for diagnostic aid, specialised image databases, including the diagnosis and a case description will need to be made available, as well, including gold standards for a proper system evaluation. A first evaluation event for image retrieval is foreseen at the 2004 CLEF conference (Cross Language Evaluation Forum) to compare text

  4. Imaging Tumor Vascularity and Response to Anti-Angiogenic Therapy Using Gaussia Luciferase.

    PubMed

    Kantar, Rami S; Lashgari, Ghazal; Tabet, Elie I; Lewandrowski, Grant K; Carvalho, Litia A; Tannous, Bakhos A

    2016-01-01

    We developed a novel approach to assess tumor vascularity using recombinant Gaussia luciferase (rGluc) protein and bioluminescence imaging. Upon intravenous injection of rGluc followed by its substrate coelenterazine, non-invasive visualization of tumor vascularity by bioluminescence imaging was possible. We applied this method for longitudinal monitoring of tumor vascularity in response to the anti-angiogenic drug tivozanib. This simple and sensitive method could be extended to image blood vessels/vasculature in many different fields. PMID:27198044

  5. Imaging Tumor Vascularity and Response to Anti-Angiogenic Therapy Using Gaussia Luciferase

    PubMed Central

    Kantar, Rami S.; Lashgari, Ghazal; Tabet, Elie I.; Lewandrowski, Grant K.; Carvalho, Litia A.; Tannous, Bakhos A.

    2016-01-01

    We developed a novel approach to assess tumor vascularity using recombinant Gaussia luciferase (rGluc) protein and bioluminescence imaging. Upon intravenous injection of rGluc followed by its substrate coelenterazine, non-invasive visualization of tumor vascularity by bioluminescence imaging was possible. We applied this method for longitudinal monitoring of tumor vascularity in response to the anti-angiogenic drug tivozanib. This simple and sensitive method could be extended to image blood vessels/vasculature in many different fields. PMID:27198044

  6. Spatially pooled contrast responses predict neural and perceptual similarity of naturalistic image categories.

    PubMed

    Groen, Iris I A; Ghebreab, Sennay; Lamme, Victor A F; Scholte, H Steven

    2012-01-01

    The visual world is complex and continuously changing. Yet, our brain transforms patterns of light falling on our retina into a coherent percept within a few hundred milliseconds. Possibly, low-level neural responses already carry substantial information to facilitate rapid characterization of the visual input. Here, we computationally estimated low-level contrast responses to computer-generated naturalistic images, and tested whether spatial pooling of these responses could predict image similarity at the neural and behavioral level. Using EEG, we show that statistics derived from pooled responses explain a large amount of variance between single-image evoked potentials (ERPs) in individual subjects. Dissimilarity analysis on multi-electrode ERPs demonstrated that large differences between images in pooled response statistics are predictive of more dissimilar patterns of evoked activity, whereas images with little difference in statistics give rise to highly similar evoked activity patterns. In a separate behavioral experiment, images with large differences in statistics were judged as different categories, whereas images with little differences were confused. These findings suggest that statistics derived from low-level contrast responses can be extracted in early visual processing and can be relevant for rapid judgment of visual similarity. We compared our results with two other, well- known contrast statistics: Fourier power spectra and higher-order properties of contrast distributions (skewness and kurtosis). Interestingly, whereas these statistics allow for accurate image categorization, they do not predict ERP response patterns or behavioral categorization confusions. These converging computational, neural and behavioral results suggest that statistics of pooled contrast responses contain information that corresponds with perceived visual similarity in a rapid, low-level categorization task. PMID:23093921

  7. Critical Evaluation of Ayurvedic Plants for Stimulating Intrinsic Antioxidant Response

    PubMed Central

    Shukla, Sunil Dutt; Bhatnagar, Maheep; Khurana, Sukant

    2012-01-01

    Oxidative damage caused by free radicals plays an important role in the causation and progression of many diseases, including aging. Free-radical damage is countered by many mechanisms, including both active antioxidant enzymatic activity in our body and passive antioxidants. Antioxidant response of our body can accommodate increased oxidative damage in diseased states to a level but beyond that level, additional antioxidants are required to combat the increased stress. Apart from the regular dietary sources of antioxidants, many traditional herbal medicines demonstrate a potential to boost antioxidant activity. Rasayana chikitsa that deals with rejuvenation and revitalization is a branch of the Indian traditional medical system of ayurveda. We review some select herbs described in rasayana chikitsa that have been assessed by modern means for stimulating intrinsic antioxidant responses in humans. A critical evaluation of rasayana chikitsa will likely provide urgently needed, actual stimulants of our physiological antioxidant responses and not just more passive antioxidants to add to an already large catalog. PMID:22855669

  8. Prospective Evaluation of Dual-Energy Imaging in Patients Undergoing Image Guided Radiation Therapy for Lung Cancer: Initial Clinical Results

    SciTech Connect

    Sherertz, Tracy; Hoggarth, Mark; Luce, Jason; Block, Alec M.; Nagda, Suneel; Harkenrider, Matthew M.; Emami, Bahman; Roeske, John C.

    2014-07-01

    Purpose: A prospective feasibility study was conducted to investigate the utility of dual-energy (DE) imaging compared to conventional x-ray imaging for patients undergoing kV-based image guided radiation therapy (IGRT) for lung cancer. Methods and Materials: An institutional review board-approved feasibility study enrolled patients with lung cancer undergoing IGRT and was initiated in September 2011. During daily setup, 2 sequential respiration-gated x-ray images were obtained using an on-board imager. Imaging was composed of 1 standard x-ray image at 120 kVp (1 mAs) and a second image obtained at 60 kVp (4 mAs). Weighted logarithmic subtraction of the 2 images was performed offline to create a soft tissue-selective DE image. Conventional and DE images were evaluated by measuring relative contrast and contrast-to-noise ratios (CNR) and also by comparing spatial localization, using both approaches. Imaging dose was assessed using a calibrated ion chamber. Results: To date, 10 patients with stage IA to IIIA lung cancer were enrolled and 57 DE images were analyzed. DE subtraction resulted in complete suppression of overlying bone in all 57 DE images, with an average improvement in relative contrast of 4.7 ± 3.3 over that of 120 kVp x-ray images (P<.0002). The improvement in relative contrast with DE imaging was seen for both smaller (gross tumor volume [GTV] ≤5 cc) and larger tumors (GTV >5 cc), with average relative contrast improvement ratios of 3.4 ± 4.1 and 5.4 ± 3.6, respectively. Moreover, the GTV was reliably localized in 95% of the DE images versus 74% of the single energy (SE images, (P=.004). Mean skin dose per DE image set was 0.44 ± 0.03 mGy versus 0.43 ± 0.03 mGy, using conventional kV imaging parameters. Conclusions: Initial results of this feasibility study suggest that DE thoracic imaging may enhance tumor localization in lung cancer patients receiving kV-based IGRT without increasing imaging dose.

  9. Magnetic resonance imaging of the liver: New imaging strategies for evaluating focal liver lesions

    PubMed Central

    Coenegrachts, Kenneth

    2009-01-01

    The early detection of focal liver lesions, particularly those which are malignant, is of utmost importance. The resection of liver metastases of some malignancies (including colorectal cancer) has been shown to improve the survival of patients. Exact knowledge of the number, size, and regional distribution of liver metastases is essential to determine their resectability. Almost all focal liver lesions larger than 10 mm are demonstrated with current imaging techniques but the detection of smaller focal liver lesions is still relatively poor. One of the advantages of magnetic resonance imaging (MRI) of the liver is better soft tissue contrast (compared to other radiologic modalities), which allows better detection and characterization of the focal liver lesions in question. Developments in MRI hardware and software and the availability of novel MRI contrast agents have further improved the diagnostic yield of MRI in lesion detection and characterization. Although the primary modalities for liver imaging are ultrasound and computed tomography, recent studies have suggested that MRI is the most sensitive method for detecting small liver metastatic lesions, and MRI is now considered the pre-operative standard method for diagnosis. Two recent developments in MRI sequences for the upper abdomen comprise unenhanced diffusion-weighted imaging (DWI), and keyhole-based dynamic contrast-enhanced (DCE) MRI (4D THRIVE). DWI allows improved detection (b = 10 s/mm2) of small (< 10 mm) focal liver lesions in particular, and is useful as a road map sequence. Also, using higher b-values, the calculation of the apparent diffusion coefficient value, true diffusion coefficient, D, and the perfusion fraction, f, has been used for the characterization of focal liver lesions. DCE 4D THRIVE enables MRI of the liver with high temporal and spatial resolution and full liver coverage. 4D THRIVE improves evaluation of focal liver lesions, providing multiple arterial and venous phases, and

  10. Monte Carlo-based adaptive EPID dose kernel accounting for different field size responses of imagers

    PubMed Central

    Wang, Song; Gardner, Joseph K.; Gordon, John J.; Li, Weidong; Clews, Luke; Greer, Peter B.; Siebers, Jeffrey V.

    2009-01-01

    The aim of this study is to present an efficient method to generate imager-specific Monte Carlo (MC)-based dose kernels for amorphous silicon-based electronic portal image device dose prediction and determine the effective backscattering thicknesses for such imagers. EPID field size-dependent responses were measured for five matched Varian accelerators from three institutions with 6 MV beams at the source to detector distance (SDD) of 105 cm. For two imagers, measurements were made with and without the imager mounted on the robotic supporting arm. Monoenergetic energy deposition kernels with 0–2.5 cm of water backscattering thicknesses were simultaneously computed by MC to a high precision. For each imager, the backscattering thickness required to match measured field size responses was determined. The monoenergetic kernel method was validated by comparing measured and predicted field size responses at 150 cm SDD, 10×10 cm2 multileaf collimator (MLC) sliding window fields created with 5, 10, 20, and 50 mm gaps, and a head-and-neck (H&N) intensity modulated radiation therapy (IMRT) patient field. Field size responses for the five different imagers deviated by up to 1.3%. When imagers were removed from the robotic arms, response deviations were reduced to 0.2%. All imager field size responses were captured by using between 1.0 and 1.6 cm backscatter. The predicted field size responses by the imager-specific kernels matched measurements for all involved imagers with the maximal deviation of 0.34%. The maximal deviation between the predicted and measured field size responses at 150 cm SDD is 0.39%. The maximal deviation between the predicted and measured MLC sliding window fields is 0.39%. For the patient field, gamma analysis yielded that 99.0% of the pixels have γ<1 by the 2%, 2 mm criteria with a 3% dose threshold. Tunable imager-specific kernels can be generated rapidly and accurately in a single MC simulation. The resultant kernels are imager position

  11. The response of fluoroscopic image intensifier-TV systems

    NASA Technical Reports Server (NTRS)

    Baily, N. A.; Keller, R. A.

    1976-01-01

    Three different types of X-ray fluoroscopic TV chains were investigated: two standard clinical units, one with a vidicon camera tube, the other with a plumbicon camera tube; and the third was a large flat-screen unit. In each an X-ray beam generated at 100 kVp was passed through 10 cm of H2O before aluminum absorbers of varying thickness were introduced. Five video recordings were made at each absorber thickness. The video image was digitized directly from the disk recording and quantized into 128 gray levels. The five recordings were averaged on a point-to-point basis, and the central 900 averaged points were again averaged to yield a value for the gray level assigned to each particular image. This 30 by 30 matrix of points corresponds to input screen areas of 29, 8.2, and 3.6 sq cm for the three units investigated.

  12. CMOS image sensor with lateral electric field modulation pixels for fluorescence lifetime imaging with sub-nanosecond time response

    NASA Astrophysics Data System (ADS)

    Li, Zhuo; Seo, Min-Woong; Kagawa, Keiichiro; Yasutomi, Keita; Kawahito, Shoji

    2016-04-01

    This paper presents the design and implementation of a time-resolved CMOS image sensor with a high-speed lateral electric field modulation (LEFM) gating structure for time domain fluorescence lifetime measurement. Time-windowed signal charge can be transferred from a pinned photodiode (PPD) to a pinned storage diode (PSD) by turning on a pair of transfer gates, which are situated beside the channel. Unwanted signal charge can be drained from the PPD to the drain by turning on another pair of gates. The pixel array contains 512 (V) × 310 (H) pixels with 5.6 × 5.6 µm2 pixel size. The imager chip was fabricated using 0.11 µm CMOS image sensor process technology. The prototype sensor has a time response of 150 ps at 374 nm. The fill factor of the pixels is 5.6%. The usefulness of the prototype sensor is demonstrated for fluorescence lifetime imaging through simulation and measurement results.

  13. Endocytosis as a Biological Response in Receptor Pharmacology: Evaluation by Fluorescence Microscopy

    PubMed Central

    Varela, María J.; de la Rocha, Arlet M. Acanda; Fernandez-Troyano, Juan C.; Barreiro, R. Belén; Lopez-Gimenez, Juan F.

    2015-01-01

    The activation of G-protein coupled receptors by agonist compounds results in diverse biological responses in cells, such as the endocytosis process consisting in the translocation of receptors from the plasma membrane to the cytoplasm within internalizing vesicles or endosomes. In order to functionally evaluate endocytosis events resulted from pharmacological responses, we have developed an image analysis method –the Q-Endosomes algorithm– that specifically discriminates the fluorescent signal originated at endosomes from that one observed at the plasma membrane in images obtained from living cells by fluorescence microscopy. Mu opioid (MOP) receptor tagged at the carboxy-terminus with yellow fluorescent protein (YFP) and permanently expressed in HEK293 cells was used as experimental model to validate this methodology. Time-course experiments performed with several agonists resulted in different sigmoid curves depending on the drug used to initiate MOP receptor endocytosis. Thus, endocytosis resulting from the simultaneous activation of co-expressed MOP and serotonin 5-HT2C receptors by morphine plus serotonin was significantly different, in kinetics as well as in maximal response parameters, from the one caused by DAMGO, sufentanyl or methadone. Therefore, this analytical tool permits the pharmacological characterization of receptor endocytosis in living cells with functional and temporal resolution. PMID:25849355

  14. Radiolabeled Apoptosis Imaging Agents for Early Detection of Response to Therapy

    PubMed Central

    2014-01-01

    Since apoptosis plays an important role in maintaining homeostasis and is associated with responses to therapy, molecular imaging of apoptotic cells could be useful for early detection of therapeutic effects, particularly in oncology. Radiolabeled annexin V compounds are the hallmark in apoptosis imaging in vivo. These compounds are reviewed from the genesis of apoptosis (cell death) imaging agents up to recent years. They have some disadvantages, including slow clearance and immunogenicity, because they are protein-based imaging agents. For this reason, several studies have been conducted in recent years to develop low molecule apoptosis imaging agents. In this review, radiolabeled phosphatidylserine targeted peptides, radiolabeled bis(zinc(II)-dipicolylamine) complex, radiolabeled 5-fluoropentyl-2-methyl-malonic acid (ML-10), caspase-3 activity imaging agents, radiolabeled duramycin, and radiolabeled phosphonium cation are reviewed as promising low-molecular-weight apoptosis imaging agents. PMID:25383382

  15. Visible to SWIR hyperspectral imaging for produce safety and quality evaluation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hyperspectral imaging techniques, combining the advantages of spectroscopy and imaging, have found wider use in food quality and safety evaluation applications during the past decade. In light of the prevalent use of hyperspectral imaging techniques in the visible to near-infrared (VNIR: 400 -1000 n...

  16. Early Prediction and Evaluation of Breast Cancer Response to Neoadjuvant Chemotherapy Using Quantitative DCE-MRI1

    PubMed Central

    Tudorica, Alina; Oh, Karen Y; Chui, Stephen Y-C; Roy, Nicole; Troxell, Megan L; Naik, Arpana; Kemmer, Kathleen A; Chen, Yiyi; Holtorf, Megan L; Afzal, Aneela; Springer, Charles S; Li, Xin; Huang, Wei

    2016-01-01

    The purpose is to compare quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) metrics with imaging tumor size for early prediction of breast cancer response to neoadjuvant chemotherapy (NACT) and evaluation of residual cancer burden (RCB). Twenty-eight patients with 29 primary breast tumors underwent DCE-MRI exams before, after one cycle of, at midpoint of, and after NACT. MRI tumor size in the longest diameter (LD) was measured according to the RECIST (Response Evaluation Criteria In Solid Tumors) guidelines. Pharmacokinetic analyses of DCE-MRI data were performed with the standard Tofts and Shutter-Speed models (TM and SSM). After one NACT cycle the percent changes of DCE-MRI parameters Ktrans (contrast agent plasma/interstitium transfer rate constant), ve (extravascular and extracellular volume fraction), kep (intravasation rate constant), and SSM-unique τi (mean intracellular water lifetime) are good to excellent early predictors of pathologic complete response (pCR) vs. non-pCR, with univariate logistic regression C statistics value in the range of 0.804 to 0.967. ve values after one cycle and at NACT midpoint are also good predictors of response, with C ranging 0.845 to 0.897. However, RECIST LD changes are poor predictors with C = 0.609 and 0.673, respectively. Post-NACT Ktrans, τi, and RECIST LD show statistically significant (P < .05) correlations with RCB. The performances of TM and SSM analyses for early prediction of response and RCB evaluation are comparable. In conclusion, quantitative DCE-MRI parameters are superior to imaging tumor size for early prediction of therapy response. Both TM and SSM analyses are effective for therapy response evaluation. However, the τi parameter derived only with SSM analysis allows the unique opportunity to potentially quantify therapy-induced changes in tumor energetic metabolism. PMID:26947876

  17. Development and evaluation of techniques for using combined microwave and optical image data for vegetation studies

    NASA Technical Reports Server (NTRS)

    Paris, J. F.; Rock, B. N.; Hsu, S. Y.

    1984-01-01

    Techniques for using combined image data from the Shuttle Imaging Radar (SIR-B) and the LANDSAT Thematic Mapper (TM) or Multispectral Scanner (MSS) for studies of irrigated crops, and boreal and deciduous forests are developed and evaluated. The effects of the structure and composition of crop canopies and soil surfaces on multiangle L-band HH (Horizontal polarization for transmission and reception) backscattering and on optical reflectance (in TM or MSS bands viewed at the nadir) are investigated. The relative accuracy of digital, calibrated SIR-B image data and LANDSAT TM or MSS image data is evaluated. Textural information extraction-techniques are developed for radar and optical image analysis.

  18. Model-based frequency response characterization of a digital-image analysis system for epifluorescence microscopy

    NASA Technical Reports Server (NTRS)

    Hazra, Rajeeb; Viles, Charles L.; Park, Stephen K.; Reichenbach, Stephen E.; Sieracki, Michael E.

    1992-01-01

    Consideration is given to a model-based method for estimating the spatial frequency response of a digital-imaging system (e.g., a CCD camera) that is modeled as a linear, shift-invariant image acquisition subsystem that is cascaded with a linear, shift-variant sampling subsystem. The method characterizes the 2D frequency response of the image acquisition subsystem to beyond the Nyquist frequency by accounting explicitly for insufficient sampling and the sample-scene phase. Results for simulated systems and a real CCD-based epifluorescence microscopy system are presented to demonstrate the accuracy of the method.

  19. Research on the evaluation method for modelling and simulation of infrared imaging sensor

    NASA Astrophysics Data System (ADS)

    Lou, Shuli; Ren, Jiancun; Liu, Liang; Li, Zhaolong

    2015-10-01

    The validity of infrared image guidance simulation is determined by the fidelity and the accuracy of modelling and simulation of infrared imaging sensor system, and the research on assessment of modelling and simulation of infrared imaging sensor is important to design and assess the IR system. A method is proposed to evaluate simulation of infrared sensor effect based on full reference quality assessment method, the evaluation index system is established to evaluate simulation fidelity of infrared imaging sensor. The accuracy of irradiance and contrast of infrared simulation image can be assessed with one-dimension histogram analysis, and the spatial correlation of image is assessed with two-dimension histogram analysis, and geometrical and gray distribution characteristics are assessed with fidelity function. With the method, modelling and simulation of infrared imaging sensor can be effectively assessed.

  20. Evaluation of an automatic brain segmentation method developed for neonates on adult MR brain images

    NASA Astrophysics Data System (ADS)

    Moeskops, Pim; Viergever, Max A.; Benders, Manon J. N. L.; Išgum, Ivana

    2015-03-01

    Automatic brain tissue segmentation is of clinical relevance in images acquired at all ages. The literature presents a clear distinction between methods developed for MR images of infants, and methods developed for images of adults. The aim of this work is to evaluate a method developed for neonatal images in the segmentation of adult images. The evaluated method employs supervised voxel classification in subsequent stages, exploiting spatial and intensity information. Evaluation was performed using images available within the MRBrainS13 challenge. The obtained average Dice coefficients were 85.77% for grey matter, 88.66% for white matter, 81.08% for cerebrospinal fluid, 95.65% for cerebrum, and 96.92% for intracranial cavity, currently resulting in the best overall ranking. The possibility of applying the same method to neonatal as well as adult images can be of great value in cross-sectional studies that include a wide age range.

  1. Evaluating performance of biomedical image retrieval systems--an overview of the medical image retrieval task at ImageCLEF 2004-2013.

    PubMed

    Kalpathy-Cramer, Jayashree; de Herrera, Alba García Seco; Demner-Fushman, Dina; Antani, Sameer; Bedrick, Steven; Müller, Henning

    2015-01-01

    Medical image retrieval and classification have been extremely active research topics over the past 15 years. Within the ImageCLEF benchmark in medical image retrieval and classification, a standard test bed was created that allows researchers to compare their approaches and ideas on increasingly large and varied data sets including generated ground truth. This article describes the lessons learned in ten evaluation campaigns. A detailed analysis of the data also highlights the value of the resources created. PMID:24746250

  2. Evaluating performance of biomedical image retrieval systems – an overview of the medical image retrieval task at ImageCLEF 2004–2013

    PubMed Central

    Kalpathy-Cramer, Jayashree; de Herrera, Alba García Seco; Demner-Fushman, Dina; Antani, Sameer; Bedrick, Steven; Müller, Henning

    2014-01-01

    Medical image retrieval and classification have been extremely active research topics over the past 15 years. With the ImageCLEF benchmark in medical image retrieval and classification a standard test bed was created that allows researchers to compare their approaches and ideas on increasingly large and varied data sets including generated ground truth. This article describes the lessons learned in ten evaluations campaigns. A detailed analysis of the data also highlights the value of the resources created. PMID:24746250

  3. Freezing effect on bread appearance evaluated by digital imaging

    NASA Astrophysics Data System (ADS)

    Zayas, Inna Y.

    1999-01-01

    In marketing channels, bread is sometimes delivered in a frozen sate for distribution. Changes occur in physical dimensions, crumb grain and appearance of slices. Ten loaves, twelve bread slices per loaf were scanned for digital image analysis and then frozen in a commercial refrigerator. The bread slices were stored for four weeks scanned again, permitted to thaw and scanned a third time. Image features were extracted, to determine shape, size and image texture of the slices. Different thresholds of grey levels were set to detect changes that occurred in crumb, images were binarized at these settings. The number of pixels falling into these gray level settings were determined for each slice. Image texture features of subimages of each slice were calculated to quantify slice crumb grain. The image features of the slice size showed shrinking of bread slices, as a results of freezing and storage, although shape of slices did not change markedly. Visible crumb texture changes occurred and these changes were depicted by changes in image texture features. Image texture features showed that slice crumb changed differently at the center of a slice compared to a peripheral area close to the crust. Image texture and slice features were sufficient for discrimination of slices before and after freezing and after thawing.

  4. Evaluation of imaging geometry for stationary chest tomosynthesis

    NASA Astrophysics Data System (ADS)

    Shan, Jing; Tucker, Andrew W.; Lee, Yueh Z.; Heath, Michael D.; Wang, Xiaohui; Foos, David; Lu, Jianping; Zhou, Otto

    2014-03-01

    We have recently demonstrated the feasibility of stationary digital chest tomosynthesis (s-DCT) using a dis- tributed carbon nanotube x-ray source array. The technology has the potential to increase the imaging resolution and speed by eliminating source motion. In addition, the flexibility in the spatial configuration of the individual sources allows new tomosynthesis imaging geometries beyond the linear scanning mode used in the conventional systems. In this paper, we report the preliminary results on the effects of the tomosynthesis imaging geometry on the image quality. The study was performed using a bench-top s-DCT system consisting of a CNT x-ray source array and a flat-panel detector. System MTF and ASF are used as quantitative measurement of the in-plane and in-depth resolution. In this study geometries with the x-ray sources arranged in linear, square, rectangular and circular configurations were investigated using comparable imaging doses. Anthropomorphic chest phantom images were acquired and reconstructed for image quality assessment. It is found that wider angular coverage results in better in-depth resolution, while the angular span has little impact on the in-plane resolution in the linear geometry. 2D source array imaging geometry leads to a more isotropic in-plane resolution, and better in-depth resolution compared to 1D linear imaging geometry with comparable angular coverage.

  5. Nuclear medicine and imaging research (instrumentation and quantitative methods of evaluation)

    SciTech Connect

    Beck, R.N.; Cooper, M.; Chen, C.T.

    1992-07-01

    This document is the annual progress report for project entitled 'Instrumentation and Quantitative Methods of Evaluation.' Progress is reported in separate sections individually abstracted and indexed for the database. Subject areas reported include theoretical studies of imaging systems and methods, hardware developments, quantitative methods of evaluation, and knowledge transfer: education in quantitative nuclear medicine imaging.

  6. Perfusion CT imaging of treatment response in oncology.

    PubMed

    Prezzi, Davide; Khan, Aisha; Goh, Vicky

    2015-12-01

    Perfusion CT was first described in the 1970s but has become accepted as a clinical technique in recent years. In oncological practice Perfusion CT allows the downstream effects of therapies on the tumour vasculature to be monitored. From the dynamic changes in tumour and vascular enhancement following intravenous iodinated contrast agent administration, qualitative and quantitative parameters may be derived that reflect tumour perfusion, blood volume, and microcirculatory changes with treatment. This review outlines the mechanisms of action of available therapies and state-of-the-art imaging practice. PMID:25864440

  7. Quantitative PET imaging of bone marrow glucose metabolic response to hematopoietic cytokines

    SciTech Connect

    Yao, W.J.; Hoh, C.K.; Hawkins, R.A.

    1995-05-01

    To evaluate the effects of hematopoietic cytokines on bone marrow glucose metabolism noninvasively, the authors studied serial quantitative FDG-PET images in 18 patients with metastic melanoma and normal bone marrow who were undergoing granulocyte-macrophage colony-stimulating factor (GMCSF) or macrophage colony-stimulating factor (MCSF) administration as an adjunct to chemotherapy. All patients received 14 days of cytokine therapy in three groups; four patients were treated with GMCSF (5 {mu}g/kg/d SQ), eight patients were treated with GMCSF (5 {mu}g/kg/d SQ) and monoclonal antibody (MAbR24) and six patients were treated with MCSF (80 {mu}g/kg/d IVCI) and MAbR24. Dynamic FDG-PET imaging was performed over the lower thoracic or upper lumbar spine at four time points in each patient. Baseline glucose metabolic rates in the bone marrow of these three groups of patients were similar (5.2 {plus_minus} 0.7, 4.4 {plus_minus} 0.8 and 4.8 {plus_minus} 1.2 {mu}g/min/g as mean value and standard deviations, respectively). In both GMCSF and GMCSF + R24 groups, rapid increases in bone marrow glucose metabolic rates were observed during therapy. After GMCSF was stopped, bone marrow glucose metabolic rates rapdily decreased in both groups. The glucose metabolic response in these two groups was not significantly different by pooled t-statistics (p = 0.105). In the MCSF + R24 group, the increase of glucose metabolic rate on Days 3 and 10 was 35% and 31% above baseline on the average, but was not significant. The results support the use of parametric FDG-PET imaging for noninvasive quantitation of bone marrow glucose metabolic changes to hematopoietic cytokines in vivo. 32 refs., 2 figs., 2 tabs.

  8. Dual-responsive polymer-coated iron oxide nanoparticles for drug delivery and imaging applications.

    PubMed

    Sundaresan, Varsha; Menon, Jyothi U; Rahimi, Maham; Nguyen, Kytai T; Wadajkar, Aniket S

    2014-05-15

    We reported the synthesis and characterization of dual-responsive poly(N-isopropylacrylamide-acrylamide-chitosan) (PAC)-coated magnetic nanoparticles (MNPs) for controlled and targeted drug delivery and imaging applications. The PAC-MNPs size was about 150nm with 70% iron mass content and excellent superparamagnetic properties. PAC-MNPs loaded with anti-cancer drug doxorubicin showed dual-responsive drug release characteristics with the maximum release of drugs at 40°C (∼78%) than at 37°C (∼33%) and at pH of 6 (∼55%) than at pH of 7.4 (∼28%) after 21 days. Further, the conjugation of prostate cancer-specific R11 peptides increased the uptake of PAC-MNPs by prostate cancer PC3 cells. The dose-dependent cellular uptake of the nanoparticles was also significantly increased with the presence of 1.3T magnetic field. The nanoparticles demonstrated cytocompatibility up to concentrations of 500μg/ml when incubated over a period of 24h with human dermal fibroblasts and normal prostate epithelial cells. Finally, pharmacokinetic studies indicated that doxorubicin-loaded PAC-MNPs caused significant prostate cancer cell death at 40°C than at 37°C, thereby confirming the temperature-dependent drug release kinetics and in vitro therapeutic efficacy. Future evaluation of in vivo therapeutic efficacy of targeted image-guided cancer therapy using R11-PAC-MNPs will reinforce a significant impact of the multifunctional PAC-MNPs on the future drug delivery systems. PMID:24607216

  9. An evaluation of cine-mode 3D portal image dosimetry for Volumetric Modulated Arc Therapy

    NASA Astrophysics Data System (ADS)

    Ansbacher, W.; Swift, C.-L.; Greer, P. B.

    2010-11-01

    We investigated cine-mode portal imaging on a Varian Trilogy accelerator and found that the linearity and other dosimetric properties are sufficient for 3D dose reconstruction as used in patient-specific quality assurance for VMAT (RapidArc) treatments. We also evaluated the gantry angle label in the portal image file header as a surrogate for the true imaged angle. The precision is only just adequate for the 3D evaluation method chosen, as discrepancies of 2° were observed.

  10. Imaging Light Responses of Foveal Ganglion Cells in the Living Macaque Eye

    PubMed Central

    Masella, Benjamin; Dalkara, Deniz; Zhang, Jie; Flannery, John. G.; Schaffer, David V.; Williams, David R.

    2014-01-01

    The fovea dominates primate vision, and its anatomy and perceptual abilities are well studied, but its physiology has been little explored because of limitations of current physiological methods. In this study, we adapted a novel in vivo imaging method, originally developed in mouse retina, to explore foveal physiology in the macaque, which permits the repeated imaging of the functional response of many retinal ganglion cells (RGCs) simultaneously. A genetically encoded calcium indicator, G-CaMP5, was inserted into foveal RGCs, followed by calcium imaging of the displacement of foveal RGCs from their receptive fields, and their intensity-response functions. The spatial offset of foveal RGCs from their cone inputs makes this method especially appropriate for fovea by permitting imaging of RGC responses without excessive light adaptation of cones. This new method will permit the tracking of visual development, progression of retinal disease, or therapeutic interventions, such as insertion of visual prostheses. PMID:24806684

  11. Imaging light responses of foveal ganglion cells in the living macaque eye.

    PubMed

    Yin, Lu; Masella, Benjamin; Dalkara, Deniz; Zhang, Jie; Flannery, John G; Schaffer, David V; Williams, David R; Merigan, William H

    2014-05-01

    The fovea dominates primate vision, and its anatomy and perceptual abilities are well studied, but its physiology has been little explored because of limitations of current physiological methods. In this study, we adapted a novel in vivo imaging method, originally developed in mouse retina, to explore foveal physiology in the macaque, which permits the repeated imaging of the functional response of many retinal ganglion cells (RGCs) simultaneously. A genetically encoded calcium indicator, G-CaMP5, was inserted into foveal RGCs, followed by calcium imaging of the displacement of foveal RGCs from their receptive fields, and their intensity-response functions. The spatial offset of foveal RGCs from their cone inputs makes this method especially appropriate for fovea by permitting imaging of RGC responses without excessive light adaptation of cones. This new method will permit the tracking of visual development, progression of retinal disease, or therapeutic interventions, such as insertion of visual prostheses. PMID:24806684

  12. Fear of negative evaluation modulates electrocortical and behavioral responses when anticipating social evaluative feedback

    PubMed Central

    Van der Molen, Melle J. W.; Poppelaars, Eefje S.; Van Hartingsveldt, Caroline T. A.; Harrewijn, Anita; Gunther Moor, Bregtje; Westenberg, P. Michiel

    2014-01-01

    Cognitive models posit that the fear of negative evaluation (FNE) is a hallmark feature of social anxiety. As such, individuals with high FNE may show biased information processing when faced with social evaluation. The aim of the current study was to examine the neural underpinnings of anticipating and processing social-evaluative feedback, and its correlates with FNE. We used a social judgment paradigm in which female participants (N = 31) were asked to indicate whether they believed to be socially accepted or rejected by their peers. Anticipatory attention was indexed by the stimulus preceding negativity (SPN), while the feedback-related negativity and P3 were used to index the processing of social-evaluative feedback. Results provided evidence of an optimism bias in social peer evaluation, as participants more often predicted to be socially accepted than rejected. Participants with high levels of FNE needed more time to provide their judgments about the social-evaluative outcome. While anticipating social-evaluative feedback, SPN amplitudes were larger for anticipated social acceptance than for social rejection feedback. Interestingly, the SPN during anticipated social acceptance was larger in participants with high levels of FNE. None of the feedback-related brain potentials correlated with the FNE. Together, the results provided evidence of biased information processing in individuals with high levels of FNE when anticipating (rather than processing) social-evaluative feedback. The delayed response times in high FNE individuals were interpreted to reflect augmented vigilance imposed by the upcoming social-evaluative threat. Possibly, the SPN constitutes a neural marker of this vigilance in females with higher FNE levels, particularly when anticipating social acceptance feedback. PMID:24478667

  13. Forensic use of photo response non-uniformity of imaging sensors and a counter method.

    PubMed

    Dirik, Ahmet Emir; Karaküçük, Ahmet

    2014-01-13

    Analogous to use of bullet scratches in forensic science, the authenticity of a digital image can be verified through the noise characteristics of an imaging sensor. In particular, photo-response non-uniformity noise (PRNU) has been used in source camera identification (SCI). However, this technique can be used maliciously to track or inculpate innocent people. To impede such tracking, PRNU noise should be suppressed significantly. Based on this motivation, we propose a counter forensic method to deceive SCI. Experimental results show that it is possible to impede PRNU-based camera identification for various imaging sensors while preserving the image quality. PMID:24515007

  14. Experimental evidence of the theoretical spatial frequency response of cubic phase mask wavefront coding imaging systems.

    PubMed

    Somayaji, Manjunath; Bhakta, Vikrant R; Christensen, Marc P

    2012-01-16

    The optical transfer function of a cubic phase mask wavefront coding imaging system is experimentally measured across the entire range of defocus values encompassing the system's functional limits. The results are compared against mathematical expressions describing the spatial frequency response of these computational imagers. Experimental data shows that the observed modulation and phase transfer functions, available spatial frequency bandwidth and design range of this imaging system strongly agree with previously published mathematical analyses. An imaging system characterization application is also presented wherein it is shown that the phase transfer function is more robust than the modulation transfer function in estimating the strength of the cubic phase mask. PMID:22274533

  15. Recovering of weather degraded images based on RGB response ratio constancy.

    PubMed

    Luzón-González, Raúl; Nieves, Juan L; Romero, Javier

    2015-02-01

    Images captured under bad weather conditions suffer from poor contrast and visibility. These effects are noticeable for haze, mist, fog, or dust storms. We have proposed a recovering method for images captured for several adverse weather conditions based on the RGB response ratio constancy under illuminant changes. This algorithm improves the visibility, contrast, and color in degraded images with low computational times. We obtain results similar to those from previously published deweathering methods but with no prior information about the image content or atmospheric parameters needed. PMID:25967830

  16. Evaluation of five non-rigid image registration algorithms using the NIREP framework

    NASA Astrophysics Data System (ADS)

    Wei, Ying; Christensen, Gary E.; Song, Joo Hyun; Rudrauf, David; Bruss, Joel; Kuhl, Jon G.; Grabowski, Thomas J.

    2010-03-01

    Evaluating non-rigid image registration algorithm performance is a difficult problem since there is rarely a "gold standard" (i.e., known) correspondence between two images. This paper reports the analysis and comparison of five non-rigid image registration algorithms using the Non-Rigid Image Registration Evaluation Project (NIREP) (www.nirep.org) framework. The NIREP framework evaluates registration performance using centralized databases of well-characterized images and standard evaluation statistics (methods) which are implemented in a software package. The performance of five non-rigid registration algorithms (Affine, AIR, Demons, SLE and SICLE) was evaluated using 22 images from two NIREP neuroanatomical evaluation databases. Six evaluation statistics (relative overlap, intensity variance, normalized ROI overlap, alignment of calcarine sulci, inverse consistency error and transitivity error) were used to evaluate and compare image registration performance. The results indicate that the Demons registration algorithm produced the best registration results with respect to the relative overlap statistic but produced nearly the worst registration results with respect to the inverse consistency statistic. The fact that one registration algorithm produced the best result for one criterion and nearly the worst for another illustrates the need to use multiple evaluation statistics to fully assess performance.

  17. Raman chemical imaging technology for food safety and quality evaluation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Raman chemical imaging combines Raman spectroscopy and digital imaging to visualize composition and morphology of a target. This technique offers great potential for food safety and quality research. Most commercial Raman instruments perform measurement at microscopic level, and the spatial range ca...

  18. Blue gum gaming machine: an evaluation of responsible gambling features.

    PubMed

    Blaszczynski, Alexander; Gainsbury, Sally; Karlov, Lisa

    2014-09-01

    Structural characteristics of gaming machines contribute to persistence in play and excessive losses. The purpose of this study was to evaluate the effectiveness of five proposed responsible gaming features: responsible gaming messages; a bank meter quarantining winnings until termination of play; alarm clock facilitating setting time-reminders; demo mode allowing play without money; and a charity donation feature where residual amounts can be donated rather than played to zero credits. A series of ten modified gaming machines were located in five Australian gambling venues. The sample comprised 300 patrons attending the venue and who played the gaming machines. Participants completed a structured interview eliciting gambling and socio-demographic data and information on their perceptions and experience of play on the index machines. Results showed that one-quarter of participants considered that these features would contribute to preventing recreational gamblers from developing problems. Just under half of the participants rated these effects to be at least moderate or significant. The promising results suggest that further refinements to several of these features could represent a modest but effective approach to minimising excessive gambling on gaming machines. PMID:23519553

  19. Criterion to Evaluate the Quality of Infrared Small Target Images

    NASA Astrophysics Data System (ADS)

    Mao, Xia; Diao, Wei-He

    2009-01-01

    In this paper, we propose a new criterion to estimate the quality of infrared small target images. To describe the criterion quantitatively, two indicators are defined. One is the “degree of target being confused” that represents the ability of infrared small target image to provide fake targets. The other one is the “degree of target being shielded”, which reflects the contribution of the image to shield the target. Experimental results reveal that this criterion is more robust than the traditional method (Signal-to-Noise Ratio). It is not only valid to infrared small target images which Signal-to-Noise Ratio could correctly describe, but also to the images that the traditional criterion could not accurately estimate. In addition, the results of this criterion can provide information about the cause of background interfering with target detection.

  20. Automatic Mapping Extraction from Multiecho T2-Star Weighted Magnetic Resonance Images for Improving Morphological Evaluations in Human Brain

    PubMed Central

    Yu, Shaode; Xie, Yaoqin

    2013-01-01

    Mapping extraction is useful in medical image analysis. Similarity coefficient mapping (SCM) replaced signal response to time course in tissue similarity mapping with signal response to TE changes in multiecho T2-star weighted magnetic resonance imaging without contrast agent. Since different tissues are with different sensitivities to reference signals, a new algorithm is proposed by adding a sensitivity index to SCM. It generates two mappings. One measures relative signal strength (SSM) and the other depicts fluctuation magnitude (FMM). Meanwhile, the new method is adaptive to generate a proper reference signal by maximizing the sum of contrast index (CI) from SSM and FMM without manual delineation. Based on four groups of images from multiecho T2-star weighted magnetic resonance imaging, the capacity of SSM and FMM in enhancing image contrast and morphological evaluation is validated. Average contrast improvement index (CII) of SSM is 1.57, 1.38, 1.34, and 1.41. Average CII of FMM is 2.42, 2.30, 2.24, and 2.35. Visual analysis of regions of interest demonstrates that SSM and FMM show better morphological structures than original images, T2-star mapping and SCM. These extracted mappings can be further applied in information fusion, signal investigation, and tissue segmentation. PMID:24379892

  1. Psychometric evaluation and refinement of the Pain Response Preference Questionnaire

    PubMed Central

    McWilliams, Lachlan A; Kowal, John; Sharpe, Donald; Dick, Bruce D

    2014-01-01

    BACKGROUND: The Pain Response Preference Questionnaire (PRPQ) assesses preferences regarding pain-related social support. The initial factor analytical study of the PRPQ produced four empirically supported scales labelled Solicitude, Management, Encouragement and Suppression. A second study produced similar findings, but suggested that the Management and Encouragement scales be combined into a single scale labelled Activity Direction. OBJECTIVES: To use factor analytical methods to evaluate these competing configurations of the PRPQ (ie, three versus four scales) and to further refine the measure. The ability of the PRPQ scales to account for pain severity and disability ratings was also evaluated. METHODS: Chronic pain patients (n=201) completed the PRPQ along with the Pain Catastrophizing Scale (PCS) and self-reports of pain severity and disability. RESULTS: Confirmatory factor analysis indicated that both models tested provided a poor fit to the data. A follow-up exploratory factor analysis was used to further refine the PRPQ scales and resulted in scales labelled Solicitude, Encouragement and Suppression. Supportive of the potential clinical utility of the PRPQ, Suppression was positively associated with pain severity and Solicitude was positively associated with disability. These two scales were also positively associated with the PCS. Supportive of the incremental validity of the PRPQ, a multiple regression analysis indicated that the Solicitude scale accounted for unique variance in disability ratings beyond that accounted for by demographic/clinical variables and the PCS. CONCLUSIONS: The PRPQ has promise as a clinical assessment measure and for advancing research examining the interpersonal context of pain. PMID:24205508

  2. Image guidance, treatment planning and evaluation of cancer interstitial focal therapy using liposomal radionuclides

    NASA Astrophysics Data System (ADS)

    Ware, Steve William

    microenvironment through correlation with in-plane compartmental sizes obtained from histopathology analysis of step-sectioned prostatectomy specimens; 2) Gauge the ability of a reader to plan an interstitial focal treatment using MRI. This was accomplished by objective measures of contrast and volume measurement with subjective reader analysis of tumor conspicuities; 3) Evaluation of the early biologic response to 186Re interstitial focal therapy. This was achieved by correlation of histochemistry (HC) markers: hetrochromatin protein alpha (HP1α), cluster of differentiation 34 (CD34), terminal deoxynucleotidal transferase nick end labeling (TUNEL), caspase 3, Ki-67 and hematoxylin & eosin (H&E) to the radiation distribution as seen on AR and radiation absorbed dose as computed from planar imaging. The conclusions of this study are that prostate MRI allows targeting of appropriate lesions for therapy by its ability to inform on the tumor microenvironment. MRI distinguishes prostatic tumors on the basis of tissue composition. Readers are better able reproduce volumes and thus plan interstitial therapy for tumors which have a denser, more homogeneous composition. The combination of SPECT and autoradiography showed a dose and position dependent expression of HC markers. These results demonstrate that multimodality imaging is capable of targeting, planning and evaluating interstitial focal therapy.

  3. Quantitative evaluation of PET image using event information bootstrap

    NASA Astrophysics Data System (ADS)

    Song, Hankyeol; Kwak, Shin Hye; Kim, Kyeong Min; Kang, Joo Hyun; Chung, Yong Hyun; Woo, Sang-Keun

    2016-04-01

    The purpose of this study was to enhance the effect in the PET image quality according to event bootstrap of small animal PET data. In order to investigate the time difference condition, realigned sinograms were generated from randomly sampled data set using bootstrap. List-mode data was obtained from small animal PET scanner for Ge-68 30 sec, Y-90 20 min and Y-90 60 min. PET image was reconstructed by Ordered Subset Expectation Maximization(OSEM) 2D with the list-mode format. Image analysis was investigated by Signal to Noise Ratio(SNR) of Ge-68 and Y-90 image. Non-parametric resampled PET image SNR percent change for the Ge-68 30 sec, Y-90 60 min, and Y-90 20 min was 1.69 %, 7.03 %, and 4.78 %, respectively. SNR percent change of non-parametric resampled PET image with time difference condition was 1.08 % for the Ge-68 30 sec, 6.74 % for the Y-90 60 min and 10.94 % for the Y-90 29 min. The result indicated that the bootstrap with time difference condition had a potential to improve a noisy Y-90 PET image quality. This method should be expected to reduce Y-90 PET measurement time and to enhance its accuracy.

  4. Synthetic tracked aperture ultrasound imaging: design, simulation, and experimental evaluation.

    PubMed

    Zhang, Haichong K; Cheng, Alexis; Bottenus, Nick; Guo, Xiaoyu; Trahey, Gregg E; Boctor, Emad M

    2016-04-01

    Ultrasonography is a widely used imaging modality to visualize anatomical structures due to its low cost and ease of use; however, it is challenging to acquire acceptable image quality in deep tissue. Synthetic aperture (SA) is a technique used to increase image resolution by synthesizing information from multiple subapertures, but the resolution improvement is limited by the physical size of the array transducer. With a large F-number, it is difficult to achieve high resolution in deep regions without extending the effective aperture size. We propose a method to extend the available aperture size for SA-called synthetic tracked aperture ultrasound (STRATUS) imaging-by sweeping an ultrasound transducer while tracking its orientation and location. Tracking information of the ultrasound probe is used to synthesize the signals received at different positions. Considering the practical implementation, we estimated the effect of tracking and ultrasound calibration error to the quality of the final beamformed image through simulation. In addition, to experimentally validate this approach, a 6 degree-of-freedom robot arm was used as a mechanical tracker to hold an ultrasound transducer and to apply in-plane lateral translational motion. Results indicate that STRATUS imaging with robotic tracking has the potential to improve ultrasound image quality. PMID:27088108

  5. [Comparison among remotely sensed image fusion methods based on spectral response function].

    PubMed

    Dou, Wen; Sun, Hong-quan; Chen, Yun-hao

    2011-03-01

    Remotely sensed image fusion is a critical issue, and many methods have been developed to inject features from a high spatial resolution panchromatic sensor into low spatial resolution multi-spectral images, trying to preserve spectral signatures while improving spatial resolution of multi-spectral images. However, no explicit physical information of the detection system has been taken into account in usual methods, which might lead to undesirable effects such as severe spectral distortion. Benefiting from the proper decomposition of the image fusion problem by a concise image fusion mathematical model, the present paper focuses on comparing reasonable modulation coefficient of spatial details based on analysis of the spectral response function (SRF). According to the classification of former methods, three modulation coefficients based on SRF of sensors were concluded, which lead to three image fusion methods incorporating spatial detail retrieved by Gaussian high-pass filter. All these methods were validated on Ikonos data compared to GS and HPM method. PMID:21595232

  6. Evaluation of Image-Guided Positioning for Frameless Intracranial Radiosurgery

    SciTech Connect

    Lamba, Michael Breneman, John C.; Warnick, Ronald E.

    2009-07-01

    Purpose: The standard for target alignment and immobilization in intracranial radiosurgery is frame-based alignment and rigid immobilization using a stereotactic head ring. Recent improvements in image-guidance systems have introduced the possibility of image-guided radiosurgery with nonrigid immobilization. We present data on the alignment accuracy and patient stability of a frameless image-guided system. Methods and Materials: Isocenter alignment errors were measured for in vitro studies in an anthropomorphic phantom for both frame-based stereotactic and frameless image-guided alignment. Subsequently, in vivo studies assessed differences between frame-based and image-guided alignment in patients who underwent frame-based intracranial radiosurgery. Finally, intratreatment target stability was determined by image-guided alignment performed before and after image-guided mask immobilized radiosurgery. Results: In vitro hidden target localization errors were comparable for the framed (0.7 {+-} 0.5 mm) and image-guided (0.6 {+-} 0.2 mm) techniques. The in vivo differences in alignment were 0.9 {+-} 0.5 mm (anteroposterior), -0.2 {+-} 0.4 mm (superoinferior), and 0.3 {+-} 0.5 mm (lateral). For in vivo stability tests, the mean distance differed between the pre- and post-treatment positions with mask-immobilized radiosurgery by 0.5 {+-} 0.3 mm. Conclusion: Frame-based and image-guided alignment accuracy in vitro was comparable for the system tested. In vivo tests showed a consistent trend in the difference of alignment in the anteroposterior direction, possibly due to torque to the ring and mounting system with frame-based localization. The mask system as used appeared adequate for patient immobilization.

  7. Usefulness of contrast-enhanced magnetic resonance imaging for evaluating solitary pulmonary nodules

    PubMed Central

    2008-01-01

    Abstract Evaluation of solitary pulmonary nodules (SPNs) poses a challenge to radiologists. Chest computed tomography (CT) is considered the standard technique for assessing morphologic findings and intrathoracic spread of an SPN. Although the clinical role of magnetic resonance imaging (MRI) for SPNs remains limited, considerable experience has been gained with MRI of thoracic diseases. Dynamic MRI and dynamic CT are useful for differentiating between malignant and benign SPNs (especially tuberculomas and hamartomas). Furthermore, dynamic MRI is useful for assessing tumor vascularity, interstitium, and vascular endothelial growth factor expression, and for predicting survival outcome among patients with peripheral pulmonary carcinoma. These advantages make dynamic MRI a promising method and a potential biomarker for characterizing tumor response to anti-angiogenic treatment as well as for predicting survival outcomes after treatment. PMID:18331971

  8. Research of the system response of neutron double scatter imaging for MLEM reconstruction

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Peng, B. D.; Sheng, L.; Li, K. N.; Zhang, X. P.; Li, Y.; Li, B. K.; Yuan, Y.; Wang, P. W.; Zhang, X. D.; Li, C. H.

    2015-03-01

    A Maximum Likelihood image reconstruction technique has been applied to neutron scatter imaging. The response function of the imaging system can be obtained by Monte Carlo simulation, which is very time-consuming if the number of image pixels and particles is large. In this work, to improve time efficiency, an analytical approach based on the probability of neutron interaction and transport in the detector is developed to calculate the system response function. The response function was applied to calculate the relative efficiency of the neutron scatter imaging system as a function of the incident neutron energy. The calculated results agreed with simulations by the MCNP5 software. Then the maximum likelihood expectation maximization (MLEM) reconstruction method with the system response function was used to reconstruct data simulated by Monte Carlo method. The results showed that there was good consistency between the reconstruction position and true position. Compared with back-projection reconstruction, the improvement in image quality was obvious, and the locations could be discerned easily for multiple radiation point sources.

  9. Multi-modality imaging of tumor phenotype and response to therapy

    NASA Astrophysics Data System (ADS)

    Nyflot, Matthew J.

    2011-12-01

    Imaging and radiation oncology have historically been closely linked. However, the vast majority of techniques used in the clinic involve anatomical imaging. Biological imaging offers the potential for innovation in the areas of cancer diagnosis and staging, radiotherapy target definition, and treatment response assessment. Some relevant imaging techniques are FDG PET (for imaging cellular metabolism), FLT PET (proliferation), CuATSM PET (hypoxia), and contrast-enhanced CT (vasculature and perfusion). Here, a technique for quantitative spatial correlation of tumor phenotype is presented for FDG PET, FLT PET, and CuATSM PET images. Additionally, multimodality imaging of treatment response with FLT PET, CuATSM, and dynamic contrast-enhanced CT is presented, in a trial of patients receiving an antiangiogenic agent (Avastin) combined with cisplatin and radiotherapy. Results are also presented for translational applications in animal models, including quantitative assessment of proliferative response to cetuximab with FLT PET and quantification of vascular volume with a blood-pool contrast agent (Fenestra). These techniques have clear applications to radiobiological research and optimized treatment strategies, and may eventually be used for personalized therapy for patients.

  10. Quantifiable Imaging Biomarkers for Evaluation of the Posterior Cruciate Ligament Using 3-T Magnetic Resonance Imaging

    PubMed Central

    Wilson, Katharine J.; Surowiec, Rachel K.; Ho, Charles P.; Devitt, Brian M.; Fripp, Jurgen; Smith, W. Sean; Spiegl, Ulrich J.; Dornan, Grant J.; LaPrade, Robert F.

    2016-01-01

    Background: Quantitative magnetic resonance imaging (MRI) techniques, such as T2 and T2 star (T2*) mapping, have been used to evaluate ligamentous tissue in vitro and to identify significant changes in structural integrity of a healing ligament. These studies lay the foundation for a clinical study that uses quantitative mapping to evaluate ligaments in vivo, particularly the posterior cruciate ligament (PCL). To establish quantitative mapping as a clinical tool for identifying and evaluating chronic or acute PCL injuries, T2 and T2* values first must be determined for an asymptomatic population. Purpose: To quantify T2 and T2* mapping properties, including texture variables (entropy, variance, contrast, homogeneity), of the PCL in an asymptomatic population. It was hypothesized that biomarker values would be consistent throughout the ligament, as measured across 3 clinically relevant subregions (proximal, middle, and distal thirds) in the asymptomatic cohort. Study Design: Cross-sectional study; Level of evidence, 4. Methods: Unilateral knee MRI scans were acquired for 25 asymptomatic subjects with a 3.0-T MRI system using T2 and T2* mapping sequences in the sagittal plane. The PCL was manually segmented and divided into thirds (proximal, middle, and distal). Summary statistics for T2 and T2* values were calculated. Intra- and interrater reliability was assessed across 3 raters to 2 time points. Results: The asymptomatic PCL cohort had mean T2 values of 36.7, 29.2, and 29.6 ms in the distal, middle, and proximal regions, respectively. The distal PCL exhibited significantly higher mean, variance, and contrast and lower homogeneity of T2 values than the middle and proximal subregions (P < .05). T2* results exhibited substantial positive skew and were therefore presented as median and quartile (Q) values. Median T2* values were 7.3 ms (Q1-Q3, 6.8-8.9 ms), 7.3 ms (Q1-Q3, 7.0-8.5 ms), and 7.3 ms (Q1-Q3, 6.4-8.2 ms) in the distal, middle, and proximal subregions

  11. Quality evaluation of adaptive optical image based on DCT and Rényi entropy

    NASA Astrophysics Data System (ADS)

    Xu, Yuannan; Li, Junwei; Wang, Jing; Deng, Rong; Dong, Yanbing

    2015-04-01

    The adaptive optical telescopes play a more and more important role in the detection system on the ground, and the adaptive optical images are so many that we need find a suitable method of quality evaluation to choose good quality images automatically in order to save human power. It is well known that the adaptive optical images are no-reference images. In this paper, a new logarithmic evaluation method based on the use of the discrete cosine transform(DCT) and Rényi entropy for the adaptive optical images is proposed. Through the DCT using one or two dimension window, the statistical property of Rényi entropy for images is studied. The different directional Rényi entropy maps of an input image containing different information content are obtained. The mean values of different directional Rényi entropy maps are calculated. For image quality evaluation, the different directional Rényi entropy and its standard deviation corresponding to region of interest is selected as an indicator for the anisotropy of the images. The standard deviation of different directional Rényi entropy is obtained as the quality evaluation value for adaptive optical image. Experimental results show the proposed method that the sorting quality matches well with the visual inspection.

  12. Evaluation of 3D multimodality image registration using receiver operating characteristic (ROC) analysis

    NASA Astrophysics Data System (ADS)

    Holton Tainter, Kerrie S.; Robb, Richard A.; Taneja, Udita; Gray, Joel E.

    1995-04-01

    Receiver operating characteristic analysis has evolved as a useful method for evaluating the discriminatory capability and efficacy of visualization. The ability of such analysis to account for the variance in decision criteria of multiple observers, multiple reading, and a wide range of difficulty in detection among case studies makes ROC especially useful for interpreting the results of a viewing experiment. We are currently using ROC analysis to evaluate the effectiveness of using fused multispectral, or complementary multimodality imaging data in the diagnostic process. The use of multispectral image recordings, gathered from multiple imaging modalities, to provide advanced image visualization and quantization capabilities in evaluating medical images is an important challenge facing medical imaging scientists. Such capabilities would potentially significantly enhance the ability of clinicians to extract scientific and diagnostic information from images. a first step in the effective use of multispectral information is the spatial registration of complementary image datasets so that a point-to-point correspondence exists between them. We are developing a paradigm of measuring the accuracy of existing image registration techniques which includes the ability to relate quantitative measurements, taken from the images themselves, to the decisions made by observers about the state of registration (SOR) of the 3D images. We have used ROC analysis to evaluate the ability of observers to discriminate between correctly registered and incorrectly registered multimodality fused images. We believe this experience is original and represents the first time that ROC analysis has been used to evaluate registered/fused images. We have simulated low-resolution and high-resolution images from real patient MR images of the brain, and fused them with the original MR to produce colorwash superposition images whose exact SOR is known. We have also attempted to extend this analysis to

  13. Digital Receptor Image Quality Evaluation: Effect of Different Filtration Schemes

    NASA Astrophysics Data System (ADS)

    Murphy, Simon; Christianson, Olav; Amurao, Maxwell; Samei, Ehsan

    2010-04-01

    The International Electrotechnical Commission provides a standard measurement methodology to provide performance intercomparison between imaging systems. Its formalism specifies beam quality based on half value layer attained by target kVp and additional Al filtration. Similar beam quality may be attained more conveniently using a filtration combination of Cu and Al. This study aimed to compare the two filtration schemes by their effects on image quality in terms of signal-difference-to-noise ratio, spatial resolution, exposure index, noise power spectrum, modulation transfer function, and detective quantum efficiency. A comparative assessment of the images was performed by analyzing commercially available image quality assessment phantom and by following the IEC 62220-3 formalism.

  14. Psychological, endocrine and neural responses to social evaluation in subclinical depression

    PubMed Central

    Duchesne, Annie; Engert, Veronika; Lue, Sonja Damika; Andrews, Julie; Efanov, Simona I.; Beaudry, Thomas; Pruessner, Jens C.

    2014-01-01

    This study aimed to identify vulnerability patterns in psychological, physiological and neural responses to mild psychosocial challenge in a population that is at a direct risk of developing depression, but who has not as yet succumbed to the full clinical syndrome. A group of healthy and a group of subclinically depressed participants underwent a modified Montreal Imaging Stress task (MIST), a mild neuroimaging psychosocial task and completed state self-esteem and mood measures. Cortisol levels were assessed throughout the session. All participants showed a decrease in performance self-esteem levels following the MIST. Yet, the decline in performance self-esteem levels was associated with increased levels of anxiety and confusion in the healthy group, but increased levels of depression in the subclinical group, following the MIST. The subclinical group showed overall lower cortisol levels compared with the healthy group. The degree of change in activity in the subgenual anterior cingulate cortex in response to negative evaluation was associated with increased levels of depression in the whole sample. Findings suggest that even in response to a mild psychosocial challenge, those individuals vulnerable to depression already show important maladaptive response patterns at psychological and neural levels. The findings point to important targets for future interventions. PMID:24078020

  15. Psychological, endocrine and neural responses to social evaluation in subclinical depression.

    PubMed

    Dedovic, Katarina; Duchesne, Annie; Engert, Veronika; Lue, Sonja Damika; Andrews, Julie; Efanov, Simona I; Beaudry, Thomas; Pruessner, Jens C

    2014-10-01

    This study aimed to identify vulnerability patterns in psychological, physiological and neural responses to mild psychosocial challenge in a population that is at a direct risk of developing depression, but who has not as yet succumbed to the full clinical syndrome. A group of healthy and a group of subclinically depressed participants underwent a modified Montreal Imaging Stress task (MIST), a mild neuroimaging psychosocial task and completed state self-esteem and mood measures. Cortisol levels were assessed throughout the session. All participants showed a decrease in performance self-esteem levels following the MIST. Yet, the decline in performance self-esteem levels was associated with increased levels of anxiety and confusion in the healthy group, but increased levels of depression in the subclinical group, following the MIST. The subclinical group showed overall lower cortisol levels compared with the healthy group. The degree of change in activity in the subgenual anterior cingulate cortex in response to negative evaluation was associated with increased levels of depression in the whole sample. Findings suggest that even in response to a mild psychosocial challenge, those individuals vulnerable to depression already show important maladaptive response patterns at psychological and neural levels. The findings point to important targets for future interventions. PMID:24078020

  16. In search of optimal fear inducing stimuli: Differential behavioral responses to computer animated images in zebrafish

    PubMed Central

    Luca, Ruxandra M.; Gerlai, Robert

    2011-01-01

    Zebrafish has been gaining popularity in behavioral genetics and behavioral neuroscience as this species offers an excellent compromise between system complexity and practical simplicity for mechanistic analyses of brain and behavior function. Recently, a number of studies started to investigate methods with which fear responses may be induced reliably in zebrafish. The ultimate goal of these studies has been to develop zebrafish models of pathological processes and to investigate the mechanisms of fear and to eventually translate the findings to the human clinic. Previously, animated image of a sympatric predator of zebrafish was shown to induce fear responses. Here we expand on this recently gained knowledge and investigate whether other moving images may induce more robust fear responses. The images investigated include the original sympatric predator, the Indian leaf fish, another sympatric predator, the needle fish, a bird silhouette moved on the side or above the tank, an expanding dot mimicking rapid approach of an object shown on the side and from above the tank, as well as non-fear inducing images including a single and a group of zebrafish. Our results indicate that although the sympatric predators do induce some fear responses, the other images, particularly the expanding dot but also the bird silhouette shown from above are more effective. The results also reveal a stimulus dependent motor pattern response repertoire of zebrafish demonstrating that perhaps univariate quantification methods may not be appropriate for uncovering the complexity of fear or anxiety related phenotypical changes in this species. PMID:21920389

  17. An evaluation of popular hyperspectral images classification approaches

    NASA Astrophysics Data System (ADS)

    Kuznetsov, Andrey; Myasnikov, Vladislav

    2015-12-01

    This work is devoted to the problem of the best hyperspectral images classification algorithm selection. The following algorithms are used for comparison: decision tree using full cross-validation; decision tree C 4.5; Bayesian classifier; maximum-likelihood method; MSE minimization classifier, including a special case - classification by conjugation; spectral angle classifier (for empirical mean and nearest neighbor), spectral mismatch classifier and support vector machine (SVM). There are used AVIRIS and SpecTIR hyperspectral images to conduct experiments.

  18. A feature-enriched completely blind image quality evaluator.

    PubMed

    Lin Zhang; Lei Zhang; Bovik, Alan C

    2015-08-01

    Existing blind image quality assessment (BIQA) methods are mostly opinion-aware. They learn regression models from training images with associated human subjective scores to predict the perceptual quality of test images. Such opinion-aware methods, however, require a large amount of training samples with associated human subjective scores and of a variety of distortion types. The BIQA models learned by opinion-aware methods often have weak generalization capability, hereby limiting their usability in practice. By comparison, opinion-unaware methods do not need human subjective scores for training, and thus have greater potential for good generalization capability. Unfortunately, thus far no opinion-unaware BIQA method has shown consistently better quality prediction accuracy than the opinion-aware methods. Here, we aim to develop an opinion-unaware BIQA method that can compete with, and perhaps outperform, the existing opinion-aware methods. By integrating the features of natural image statistics derived from multiple cues, we learn a multivariate Gaussian model of image patches from a collection of pristine natural images. Using the learned multivariate Gaussian model, a Bhattacharyya-like distance is used to measure the quality of each image patch, and then an overall quality score is obtained by average pooling. The proposed BIQA method does not need any distorted sample images nor subjective quality scores for training, yet extensive experiments demonstrate its superior quality-prediction performance to the state-of-the-art opinion-aware BIQA methods. The MATLAB source code of our algorithm is publicly available at www.comp.polyu.edu.hk/~cslzhang/IQA/ILNIQE/ILNIQE.htm. PMID:25915960

  19. Evaluation of a photon-counting breast tomosynthesis imaging system

    NASA Astrophysics Data System (ADS)

    Maidment, Andrew D. A.; Ullberg, Christer; Lindman, Karin; Adelöw, Leif; Egerström, Johan; Eklund, Mathias; Francke, Tom; Jordung, Ulf; Kristoffersson, Tomas; Lindqvist, Lars; Marchal, Daniel; Olla, Hans; Penton, Erik; Rantanen, Juha; Solokov, Skiff; Weber, Niclas; Westerberg, Hans

    2006-03-01

    Digital breast tomosynthesis promises solutions to many of the problems associated with projection mammography, including elimination of artifactual densities due to the superposition of normal tissues and increasing the conspicuity of true lesions that would otherwise be masked by superimposed normal tissue. We have investigated tomosynthesis using a digital camera containing 48 photon counting, orientation sensitive, linear detectors which are precisely aligned with the focal spot of the x-ray source. The x-ray source and the digital detectors are scanned in a continuous motion across the object (patient), each linear detector collecting an image at a distinct angle. A preliminary assessment of tomosynthesis image quality has been performed with both qualitative and quantitative methods. Measured values of MTF and NPS appear concordant with theoretical values. The MTF in the scanning direction is dominated by scanning unsharpness and geometric factors, while the NPS is white. The MTF and NPS in the strip direction are somewhat lower than in the scan direction. The NPS of tomographic images show a slight decrease with increasing spatial frequency, related to the sampling and interpolation in the reconstruction process. A phase I clinical trial is ongoing; 9 women have been recruited. Breast positioning is comparable to other imaging systems. The visualization of breast anatomy appears to be superior to screen-film mammography, at the same average glandular dose. Examination of images reconstructed with a sub-sampled set of projection images appears to support the hypothesis that image quality is superior when more projection images are used in the reconstruction.

  20. Quantitative identification of magnetic resonance imaging features of prostate cancer response following laser ablation and radical prostatectomy

    PubMed Central

    Litjens, Geert J. S.; Huisman, Henkjan J.; Elliott, Robin M.; Shih, Natalie Nc.; Feldman, Michael D.; Viswanath, Satish; Fütterer, Jurgen J.; Bomers, Joyce G. R.; Madabhushi, Anant

    2014-01-01

    Abstract. Laser interstitial thermotherapy (LITT) is a relatively new focal therapy technique for the ablation of localized prostate cancer. In this study, for the first time, we are integrating ex vivo pathology and magnetic resonance imaging (MRI) to assess the imaging characteristics of prostate cancer and treatment changes following LITT. Via a unique clinical trial, which gave us the availability of ex vivo histology and pre- and post-LITT MRIs, (1) we investigated the imaging characteristics of treatment effects and residual disease, and (2) evaluated treatment-induced feature changes in the ablated area relative to the residual disease. First, a pathologist annotated the ablated area and the residual disease on the ex vivo histology. Subsequently, we transferred the annotations to the post-LITT MRI using a semi-automatic elastic registration. The pre- and post-LITT MRIs were registered and features were extracted. A scoring metric based on the change in median pre- and post-LITT feature values was introduced, which allowed us to identify the most treatment responsive features. Our results show that (1) image characteristics for treatment effects and residual disease are different, and (2) the change of feature values between pre- and post-LITT MRIs can be a quantitative biomarker for treatment response. Finally, using feature change improved discrimination between the residual disease and treatment effects. PMID:26158070

  1. Mechanical Model Analysis for Quantitative Evaluation of Liver Fibrosis Based on Ultrasound Tissue Elasticity Imaging

    NASA Astrophysics Data System (ADS)

    Shiina, Tsuyoshi; Maki, Tomonori; Yamakawa, Makoto; Mitake, Tsuyoshi; Kudo, Masatoshi; Fujimoto, Kenji

    2012-07-01

    Precise evaluation of the stage of chronic hepatitis C with respect to fibrosis has become an important issue to prevent the occurrence of cirrhosis and to initiate appropriate therapeutic intervention such as viral eradication using interferon. Ultrasound tissue elasticity imaging, i.e., elastography can visualize tissue hardness/softness, and its clinical usefulness has been studied to detect and evaluate tumors. We have recently reported that the texture of elasticity image changes as fibrosis progresses. To evaluate fibrosis progression quantitatively on the basis of ultrasound tissue elasticity imaging, we introduced a mechanical model of fibrosis progression and simulated the process by which hepatic fibrosis affects elasticity images and compared the results with those clinical data analysis. As a result, it was confirmed that even in diffuse diseases like chronic hepatitis, the patterns of elasticity images are related to fibrous structural changes caused by hepatic disease and can be used to derive features for quantitative evaluation of fibrosis stage.

  2. Quality metric in matched Laplacian of Gaussian response domain for blind adaptive optics image deconvolution

    NASA Astrophysics Data System (ADS)

    Guo, Shiping; Zhang, Rongzhi; Yang, Yikang; Xu, Rong; Liu, Changhai; Li, Jisheng

    2016-04-01

    Adaptive optics (AO) in conjunction with subsequent postprocessing techniques have obviously improved the resolution of turbulence-degraded images in ground-based astronomical observations or artificial space objects detection and identification. However, important tasks involved in AO image postprocessing, such as frame selection, stopping iterative deconvolution, and algorithm comparison, commonly need manual intervention and cannot be performed automatically due to a lack of widely agreed on image quality metrics. In this work, based on the Laplacian of Gaussian (LoG) local contrast feature detection operator, we propose a LoG domain matching operation to perceive effective and universal image quality statistics. Further, we extract two no-reference quality assessment indices in the matched LoG domain that can be used for a variety of postprocessing tasks. Three typical space object images with distinct structural features are tested to verify the consistency of the proposed metric with perceptual image quality through subjective evaluation.

  3. Breast imaging with SoftVue: initial clinical evaluation

    NASA Astrophysics Data System (ADS)

    Duric, Neb; Littrup, Peter; Li, Cuiping; Roy, Olivier; Schmidt, Steven; Cheng, Xiaoyang; Seamans, John; Wallen, Andrea; Bey-Knight, Lisa

    2014-03-01

    We describe the clinical performance of SoftVue, a breast imaging device based on the principles of ultrasound tomography. Participants were enrolled in an IRB-approved study at Wayne State University, Detroit, MI. The main research findings indicate that SoftVue is able to image the whole uncompressed breast up to cup size H. Masses can be imaged in even the densest breasts with the ability to discern margins and mass shapes. Additionally, it is demonstrated that multi-focal disease can also be imaged. The system was also tested in its research mode for additional imaging capabilities. These tests demonstrated the potential for generating tissue stiffness information for the entire breast using through-transmission data. This research capability differentiates SoftVue from the other whole breast systems on the market. It is also shown that MRI-like images can be generated using alternative processing of the echo data. Ongoing research is focused on validating and quantifying these findings in a larger sample of study participants and quantifying SoftVue's ability to differentiate benign masses from cancer.

  4. MR Imaging Biomarkers to Monitor Early Response to Hypoxia-Activated Prodrug TH-302 in Pancreatic Cancer Xenografts

    PubMed Central

    Zhang, Xiaomeng; Wojtkowiak, Jonathan W.; Martinez, Gary V.; Cornnell, Heather H.; Hart, Charles P.; Baker, Amanda F.; Gillies, Robert

    2016-01-01

    TH-302 is a hypoxia-activated prodrug known to activate selectively under the hypoxic conditions commonly found in solid tumors. It is currently being evaluated in clinical trials, including two trials in Pancreatic Ductal Adenocarcinomas (PDAC). The current study was undertaken to evaluate imaging biomarkers for prediction and response monitoring of TH-302 efficacy in xenograft models of PDAC. Dynamic contrast-enhanced (DCE) and diffusion weighted (DW) magnetic resonance imaging (MRI) were used to monitor acute effects on tumor vasculature and cellularity, respectively. Three human PDAC xenografts with known differential responses to TH-302 were imaged prior to, and at 24 h and 48 hours following a single dose of TH-302 or vehicle to determine if imaging changes presaged changes in tumor volumes. DW-MRI was performed at five b-values to generate apparent diffusion coefficient of water (ADC) maps. For DCE-MRI, a standard clinically available contrast reagent, Gd-DTPA, was used to determine blood flow into the tumor region of interest. TH-302 induced a dramatic decrease in the DCE transfer constant (Ktrans) within 48 hours after treatment in the sensitive tumors, Hs766t and Mia PaCa-2, whereas TH-302 had no effect on the perfusion behavior of resistant SU.86.86 tumors. Tumor cellularity, estimated from ADC, was significantly increased 24 and 48 hours after treatment in Hs766t, but was not observed in the Mia PaCa-2 and SU.86.86 groups. Notably, growth inhibition of Hs766t was observed immediately (day 3) following initiation of treatment, but was not observed in MiaPaCa-2 tumors until 8 days after initiation of treatment. Based on these preclinical findings, DCE-MRI measures of vascular perfusion dynamics and ADC measures of cell density are suggested as potential TH-302 response biomarkers in clinical trials. PMID:27227903

  5. Evaluation of normalized metal artifact reduction (NMAR) in kVCT using MVCT prior images for radiotherapy treatment planning

    SciTech Connect

    Paudel, M. R.; Mackenzie, M.; Rathee, S.; Fallone, B. G.; Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2; Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2

    2013-08-15

    Purpose: To evaluate the metal artifacts in kilovoltage computed tomography (kVCT) images that are corrected using a normalized metal artifact reduction (NMAR) method with megavoltage CT (MVCT) prior images.Methods: Tissue characterization phantoms containing bilateral steel inserts are used in all experiments. Two MVCT images, one without any metal artifact corrections and the other corrected using a modified iterative maximum likelihood polychromatic algorithm for CT (IMPACT) are translated to pseudo-kVCT images. These are then used as prior images without tissue classification in an NMAR technique for correcting the experimental kVCT image. The IMPACT method in MVCT included an additional model for the pair/triplet production process and the energy dependent response of the MVCT detectors. An experimental kVCT image, without the metal inserts and reconstructed using the filtered back projection (FBP) method, is artificially patched with the known steel inserts to get a reference image. The regular NMAR image containing the steel inserts that uses tissue classified kVCT prior and the NMAR images reconstructed using MVCT priors are compared with the reference image for metal artifact reduction. The Eclipse treatment planning system is used to calculate radiotherapy dose distributions on the corrected images and on the reference image using the Anisotropic Analytical Algorithm with 6 MV parallel opposed 5 × 10 cm{sup 2} fields passing through the bilateral steel inserts, and the results are compared. Gafchromic film is used to measure the actual dose delivered in a plane perpendicular to the beams at the isocenter.Results: The streaking and shading in the NMAR image using tissue classifications are significantly reduced. However, the structures, including metal, are deformed. Some uniform regions appear to have eroded from one side. There is a large variation of attenuation values inside the metal inserts. Similar results are seen in commercially corrected image

  6. Early-Stage Imaging of Nanocarrier-Enhanced Chemotherapy Response in Living Subjects by Scalable Photoacoustic Microscopy

    PubMed Central

    2015-01-01

    Conventional evaluation methods of chemotherapeutic efficacy such as tissue biopsy and anatomical measurement are either invasive with potential complications or dilatory to capture the rapid pathological changes. Here, a sensitive and resolution-scalable photoacoustic microscopy (PAM) with theranostic nanoformulation was developed to noninvasively monitor the therapy response in a timely manner. Ultrasmall graphene oxide nanosheets were designed as both drug-loading vehicle and photoacoustic signal amplifier to the tumor. With the signal enhancement by the injected contrast agents, the subtle microvascular changes of the chemotherapy response in tumor were advantagely revealed by our PAM system, which was much earlier than the morphological measurement by standard imaging techniques. High tumor uptake of the enhanced nanodrug with Cy5.5 labeling was validated by fluorescence imaging. At different observation scales, PAM offered unprecedented sensitivity of optical absorption and high spatial resolution over optical imaging. Our studies demonstrate the PAM system with synergistic theranostic strategy to be a multiplexing platform for tumor diagnosis, drug delivery, and chemotherapy response monitoring at a very early stage and in an effective way. PMID:25406986

  7. Responsible practices, proactive communications yield positive environmental image

    SciTech Connect

    Warner, D. )

    1994-02-01

    Industrial corporations nationwide are struggling to maintain their standing as good community citizens and neighbors in an era of heightened public awareness about environmental issues. The challenge of achieving and maintaining compliance with tens of thousands of pages of environmental regulations is s formidable task. In addition, most major companies work hard to protect their employees and surrounding communities from the hazards of environmental accidents. Nevertheless, despite substantial efforts and large expenditures on environmental programs, companies increasingly find their environmental images tarnished over relatively minor incidents or issues, some of which the companies cannot control. Industrial organizations traditionally could conduct business behind closed doors. However, the rules of the game changed during the last decade. The federal government and many states have passed freedom of information laws allowing public access to government records, including environmental permit documents. Worker right-to-know laws were passed to inform workers of the potential hazards of chemicals in the workplace. SARA encompasses the Emergency Planning and Community Right-to-know Act (EPCRA; commonly known as SARA Title III). This statute provides citizens direct access to chemical inventory information and toxic emissions data for industries within their communities. In many areas of the country, news media have collected the toxic emissions reports required under this program to prepare a list of dirty dozen industries in their states or communities. Such laws have placed large volumes of technical environmental information on industry into the hands of the public, without also providing guidance for understanding or interpreting the data. One result has been numerous citizen misunderstandings about the environmental risks specific facilities pose to a community.

  8. Three-dimensional integral imaging displays using a quick-response encoded elemental image array: an overview

    NASA Astrophysics Data System (ADS)

    Markman, A.; Javidi, B.

    2016-06-01

    Quick-response (QR) codes are barcodes that can store information such as numeric data and hyperlinks. The QR code can be scanned using a QR code reader, such as those built into smartphone devices, revealing the information stored in the code. Moreover, the QR code is robust to noise, rotation, and illumination when scanning due to error correction built in the QR code design. Integral imaging is an imaging technique used to generate a three-dimensional (3D) scene by combining the information from two-dimensional (2D) elemental images (EIs) each with a different perspective of a scene. Transferring these 2D images in a secure manner can be difficult. In this work, we overview two methods to store and encrypt EIs in multiple QR codes. The first method uses run-length encoding with Huffman coding and the double-random-phase encryption (DRPE) to compress and encrypt an EI. This information is then stored in a QR code. An alternative compression scheme is to perform photon-counting on the EI prior to compression. Photon-counting is a non-linear transformation of data that creates redundant information thus improving image compression. The compressed data is encrypted using the DRPE. Once information is stored in the QR codes, it is scanned using a smartphone device. The information scanned is decompressed and decrypted and an EI is recovered. Once all EIs have been recovered, a 3D optical reconstruction is generated.

  9. Psychophysical experiments for evaluating target distinctness in images

    NASA Astrophysics Data System (ADS)

    Copeland, Anthony C.; Trivedi, Mohan M.; McManamey, James R.

    1995-06-01

    An experimental design has been developed to facilitate collection of data for developing and testing computational models for assessment of the perceptual similarity or difference of texture patterns. This experimental design is based on Thurstone's Law of Comparative Judgement. To facilitate consistency in presentation of stimuli, collection of data, and computation of psychological scale values, an X-windows testing environment has been developed called the X-based Perceptual Experiment Testbed (XPET). A pilot study was conducted utilizing this experimental design. The study utilized images in which targets and their associated background had uncorrelated Gaussian noise texture patterns. Thus, only first- order image statistics were of significance. Psychological scale values for `target distinctness' obtained using this experimental design were compared to several first-order image metrics. Correlation coefficients as high as 0.9881 were found between the psychological scale values and first-order image metrics. It has been concluded that this experimental design should be adequate for data collection to support development of new second-order image metrics.

  10. Performance evaluation of image-intensifier-TV fluoroscopy systems

    NASA Astrophysics Data System (ADS)

    van der Putten, Wilhelm J.; Bouley, Shawn

    1995-05-01

    Through use of a computer model and an aluminum low contrast phantom developed in-house, a method has been developed which is able to grade the imaging performance of fluoroscopy systems through use of a variable, K. This parameter was derived from Rose's model of image perception and is here used as a figure of merit to grade fluoroscopy systems. From Rose's model for an ideal system, a typical value of K for the perception of low contrast details should be between 3 and 7, assuming threshold vision by human observers. Thus, various fluoroscopy systems are graded with different values of K, with a lower value of K indicating better imaging performance of the system. A series of fluoroscopy systems have been graded where the best system produces a value in the low teens, while the poorest systems produce a value in the low twenties. Correlation with conventional image quality measurements is good and the method has the potential for automated assessment of image quality.

  11. An augmented parametric response map with consideration of image registration error: towards guidance of locally adaptive radiotherapy

    NASA Astrophysics Data System (ADS)

    Lausch, Anthony; Chen, Jeff; Ward, Aaron D.; Gaede, Stewart; Lee, Ting-Yim; Wong, Eugene

    2014-11-01

    Parametric response map (PRM) analysis is a voxel-wise technique for predicting overall treatment outcome, which shows promise as a tool for guiding personalized locally adaptive radiotherapy (RT). However, image registration error (IRE) introduces uncertainty into this analysis which may limit its use for guiding RT. Here we extend the PRM method to include an IRE-related PRM analysis confidence interval and also incorporate multiple graded classification thresholds to facilitate visualization. A Gaussian IRE model was used to compute an expected value and confidence interval for PRM analysis. The augmented PRM (A-PRM) was evaluated using CT-perfusion functional image data from patients treated with RT for glioma and hepatocellular carcinoma. Known rigid IREs were simulated by applying one thousand different rigid transformations to each image set. PRM and A-PRM analyses of the transformed images were then compared to analyses of the original images (ground truth) in order to investigate the two methods in the presence of controlled IRE. The A-PRM was shown to help visualize and quantify IRE-related analysis uncertainty. The use of multiple graded classification thresholds also provided additional contextual information which could be useful for visually identifying adaptive RT targets (e.g. sub-volume boosts). The A-PRM should facilitate reliable PRM guided adaptive RT by allowing the user to identify if a patient’s unique IRE-related PRM analysis uncertainty has the potential to influence target delineation.

  12. Development and evaluation of a new radiographic and fluoroscopic imager based on electron-multiplying CCDs: The solid state x-ray image intensifier

    NASA Astrophysics Data System (ADS)

    Kuhls-Gilcrist, Andrew Thomas

    assessment of spatial resolution, noise performance, and overall performance was then determined using MTF, INEE, and DQE measurements. In addition to the overall performance of the SSXII, the performances of individual components were determined using measurements of their resolution and transmission efficiency. The unique ability of the SSXII to operate in both tradition energy integrating (EI) mode and single photon counting (SPC) mode was also demonstrated. To better assess detector performance, a new method for determination of the two-dimensional presampled MTF, the "noise-response method", was developed and evaluated. Compared to current measurement methods, the noise-response method simplifies the MTF determination by eliminating the need for manufacture and alignment of precisely machined test objects, thereby eliminating inaccuracies that result from the use of such objects and subsequent analysis of the resulting images. The accuracy of this method was demonstrated using both simulated and experimental data sets. For the simulated image set which used a simple detector model for which the "true" MTF was known exactly, excellent agreement was obtained with the MTF determined using the noise-response method, with a maximum deviation of 1.1%. Comparison measurements were also made on this simulated data set with the established edge-response method and these showed deviations greater than 35% from the "true" MTF. Experimental measurements on a range of detector technologies (including an XII, FPD and SSXII) demonstrated agreement between the noise-response and edge-response methods within experimental uncertainty, with discrepancies likely resulting from errors inherent in the edge-response MTF procedure. The two-dimensional MTF for the FPD was non-isotropic, with an increase observed on the diagonals, whereas the SSXII MTF was shown to be largely symmetric. Initial results indicate that the new noise-response method is a promising candidate to replace existing

  13. Creating culturally responsive family therapy models and research: introducing the use of responsive evaluation as a method.

    PubMed

    Seponski, Desiree M; Bermudez, J Maria; Lewis, Denise C

    2013-01-01

    Models of marriage and family therapy (MFT) typically reflect Western values and norms, and although cultural adaptations are made, many models/frameworks continue to be inappropriate or inadequate for use with non-Western cultures. Worldwide, therapists are examining ways of using MFT models in a culturally sensitive manner, especially when working with clients who are seen as having minority status or perceived as "other" by the dominant group. This essay suggests the use of responsive evaluation as a theoretically consistent methodology for creating and evaluating culturally responsive therapies. This approach rigorously evaluates each unique client/therapist context, culture, power, needs, and beliefs. We describe responsive evaluation and discuss how each component addresses the research needs of examining culturally responsive family therapies. A case illustration is offered delineating the process of conducting culturally responsive therapy with a Cambodian sample using solution-focused and narrative therapy. PMID:25073841

  14. Perceptual difference model (Case-PDM) for evaluation of MR images: validation and calibration

    NASA Astrophysics Data System (ADS)

    Miao, Jun; Huo, Donglai; Wilson, David

    2007-03-01

    There is an extraordinary number of fast MR imaging techniques, especially for parallel imaging. When one considers multiple reconstruction algorithms, reconstruction parameters, coil configurations, acceleration factors, noise levels, and multiple test images, one can easily create 1000's of test images for image quality evaluation. We have found the perceptual difference model (Case-PDM) to be quite useful as a means of rapid quantitative image quality evaluation in such experiments, and have applied it to keyhole, spiral, SENSE, and GRAPPA applications. In this study, we have compared human evaluation of MR images from multiple organs and from multiple image reconstruction algorithms to Case-PDM. We compared human DSCQS (Double Stimulus Continuous Quality Scale) scoring against Case-PDM measurements for 3 different image types and 3 different image reconstruction algorithms. We found that Case-PDM linearly correlated (r > 0.9) with human subject ratings over a very large range of image quality. We also compared Case-PDM to other image quality evaluation methods. Case-PDM generally performed better than NASA's DCTune, MITRE's IQM, Zhou Wang's NR models and mean square error (MSE) method, by showing a higher Pearson correlation coefficient, higher Spearman rank-order correlation and lower root-mean-squared error. All three models (Case-PDM, Sarnoff's IDM, and Zhou Wang's SSIM) performed very similarly in this experiment. To focus on high quality reconstructions, we performed a 2-AFC (Alternate Forced Choice) experiment to determine the "just perceptible difference" between two images. We found that threshold Case-PDM scores changed little (0.6-1.8) with 2 different image types and 3 degradation patterns, and results with Case-PDM were much tighter than the other methods (IDM and MSE) by showing a lower ratio of mean to standard deviation value. We conclude that Case-PDM can correctly predict the ordering of image quality over a large range of image quality. Case

  15. Evaluation of security algorithms used for security processing on DICOM images

    NASA Astrophysics Data System (ADS)

    Chen, Xiaomeng; Shuai, Jie; Zhang, Jianguo; Huang, H. K.

    2005-04-01

    In this paper, we developed security approach to provide security measures and features in PACS image acquisition and Tele-radiology image transmission. The security processing on medical images was based on public key infrastructure (PKI) and including digital signature and data encryption to achieve the security features of confidentiality, privacy, authenticity, integrity, and non-repudiation. There are many algorithms which can be used in PKI for data encryption and digital signature. In this research, we select several algorithms to perform security processing on different DICOM images in PACS environment, evaluate the security processing performance of these algorithms, and find the relationship between performance with image types, sizes and the implementation methods.

  16. Altered brain activation during response inhibition and error processing in subjects with Internet gaming disorder: a functional magnetic imaging study.

    PubMed

    Ko, Chih-Hung; Hsieh, Tsyh-Jyi; Chen, Chiao-Yun; Yen, Cheng-Fang; Chen, Cheng-Sheng; Yen, Ju-Yu; Wang, Peng-Wei; Liu, Gin-Chung

    2014-12-01

    The aim of the present study was to evaluate the impulsivity and brain correlates of response inhibition and error processing among subjects with Internet gaming disorder (IGD). We evaluated the response inhibition and error processing by functional magnetic resonance imaging (fMRI) in subjects with IGD and controls. Twenty-six men with IGD for at least 2 years and 23 controls with no history of IGD were recruited as the IGD and control groups, respectively. All subjects performed the event-related designed Go/No-go task under fMRI and completed questionnaires related to Internet addiction and impulsivity. The IGD group exhibited a higher score for impulsivity than the control group. The IGD group also exhibited higher brain activation when processing response inhibition over the left orbital frontal lobe and bilateral caudate nucleus than controls. Both the IGD and control groups exhibited activation of the insula and anterior cingulate cortex during error processing. The activation over the right insula was lower in the subjects with IGD than the control group. Our results support the fact that the fronto-striatal network involved in response inhibition, and the salience network, anchored by the anterior cingulate and insula, contributes to error processing. Further, adults with IGD have impaired insular function in error processing and greater activation of the fronto-striatal network in order to maintain their response inhibition performance. PMID:24469099

  17. Development of proton CT imaging system for evaluation of proton range calculation accuracy

    NASA Astrophysics Data System (ADS)

    Tanaka, Sodai; Nishio, Teiji; Matsushita, Keiichiro; Tsuneda, Masato; Aono, Yuki; Kabuki, Shigeto; Sugiura, Akinori; Uesaka, Mitsuru

    2014-09-01

    [Purpose] In treatment planning of proton therapy, X-ray CT image is generally utilized for proton dose and range calculations in a patient body. However, there is an error of the conversion from CT value to WEL (Water Equivalent Length), and it turns into the error of proton range calculation. Therefore, WEL can be directly derived by use of pixel value on proton CT (pCT) image. The purpose of this study is development of a simple and convenient pCT imaging system for evaluation of proton range calculation accuracy. [Method] PCT imaging system was constructed with a plastic scintillator and a cooled CCD camera, which acquires the image of integrated value of the scintillation light toward the beam direction. Experiment for evaluation of this system with 70-MeV protons provided by NIRS cyclotron was performed. The proton beam was irradiated to objects of water and other substances phantom with complicated shape. The pCT image reconstructed from the experimental data was quantitatively evaluated. [Result] Construction of pCT image of various objects was successful. The value of WEL factor of water was 1.0 +/-0.1. [Conclusion] The simple and convenient pCT imaging system for evaluation of proton range calculation accuracy was developed and was evaluated by experiment using proton beam.

  18. A New Method for Geometric Quality Evaluation of Remote Sensing Image Based on Information Entropy

    NASA Astrophysics Data System (ADS)

    Jiao, W.; Long, T.; Yang, G.; He, G.

    2014-11-01

    Geometric accuracy of the remote sensing rectified image is usually evaluated by the root-mean-square errors (RMSEs) of the ground control points (GCPs) and check points (CPs). These discrete geometric accuracy index data represent only on a local quality of the image with statistical methods. In addition, the traditional methods only evaluate the difference between the rectified image and reference image, ignoring the degree of the original image distortion. A new method of geometric quality evaluation of remote sensing image based on the information entropy is proposed in this paper. The information entropy, the amount of information and the uncertainty interval of the image before and after rectification are deduced according to the information theory. Four kind of rectification model and seven situations of GCP distribution are applied on the remotely sensed imagery in the experiments. The effective factors of the geometrical accuracy are analysed and the geometric qualities of the image are evaluated in various situations. Results show that the proposed method can be used to evaluate the rectification model, the distribution model of GCPs and the uncertainty of the remotely sensed imagery, and is an effective and objective assessment method.

  19. Estimation of Response Functions Based on Variational Bayes Algorithm in Dynamic Images Sequences

    PubMed Central

    2016-01-01

    We proposed a nonparametric Bayesian model based on variational Bayes algorithm to estimate the response functions in dynamic medical imaging. In dynamic renal scintigraphy, the impulse response or retention functions are rather complicated and finding a suitable parametric form is problematic. In this paper, we estimated the response functions using nonparametric Bayesian priors. These priors were designed to favor desirable properties of the functions, such as sparsity or smoothness. These assumptions were used within hierarchical priors of the variational Bayes algorithm. We performed our algorithm on the real online dataset of dynamic renal scintigraphy. The results demonstrated that this algorithm improved the estimation of response functions with nonparametric priors.

  20. Automatic evaluation of nickel alloy secondary phases from SEM images.

    PubMed

    de Albuquerque, Victor Hugo C; Silva, Cleiton Carvalho; Menezes, Thiago Ivo de S; Farias, Jesualdo Pereira; Tavares, João Manuel R S

    2011-01-01

    Quantitative metallography is a technique to determine and correlate the microstructures of materials with their properties and behavior. Generic commercial image processing and analysis software packages have been used to quantify material phases from metallographic images. However, these all-purpose solutions also have some drawbacks, particularly when applied to segmentation of material phases. To overcome such limitations, this work presents a new solution to automatically segment and quantify material phases from SEM metallographic images. The solution is based on a neuronal network and in this work was used to identify the secondary phase precipitated in the gamma matrix of a Nickel base alloy. The results obtained by the new solution were validated by visual inspection and compared with the ones obtained by a commonly used commercial software. The conclusion is that the new solution is precise, reliable and more accurate and faster than the commercial software. PMID:21181708

  1. Design, Synthesis, and Evaluation of Fluorinated Radioligands for Myelin Imaging.

    PubMed

    Tiwari, Anand Dev; Wu, Chunying; Zhu, Junqing; Zhang, Sheng; Zhu, Jinle; Wang, William R; Zhang, Jinming; Tatsuoka, Curtis; Matthews, Paul M; Miller, Robert H; Wang, Yanming

    2016-04-28

    Myelination is one of the fundamental processes in vertebrates. A major challenge is to quantitatively image myelin distribution in the central nervous system. For this reason, we designed and synthesized a series of fluorinated radioligands that can be radiolabeled as radiotracers for positron emission tomography (PET) imaging of myelin. These newly developed radioligands readily penetrate the blood-brain barrier and selectively bind to myelin membranes in the white matter region. Structure-activity relationship studies of such ligands suggested that optimal permeability could be achieved with calculated lipophilicty in the range of 3-4. After radiolabeling with fluorine-18, the brain uptake and retention of each radioligand were determined by microPET/CT imaging studies. These pharmacokinetic studies led us to identify a lead compound ([(18)F]FMeDAS, 32) with promising in vivo binding properties, which was subsequently validated by ex vivo autoradiography. PMID:27070324

  2. 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.

  3. Unsupervised Feature Learning Improves Prediction of Human Brain Activity in Response to Natural Images

    PubMed Central

    Güçlü, Umut; van Gerven, Marcel A. J.

    2014-01-01

    Encoding and decoding in functional magnetic resonance imaging has recently emerged as an area of research to noninvasively characterize the relationship between stimulus features and human brain activity. To overcome the challenge of formalizing what stimulus features should modulate single voxel responses, we introduce a general approach for making directly testable predictions of single voxel responses to statistically adapted representations of ecologically valid stimuli. These representations are learned from unlabeled data without supervision. Our approach is validated using a parsimonious computational model of (i) how early visual cortical representations are adapted to statistical regularities in natural images and (ii) how populations of these representations are pooled by single voxels. This computational model is used to predict single voxel responses to natural images and identify natural images from stimulus-evoked multiple voxel responses. We show that statistically adapted low-level sparse and invariant representations of natural images better span the space of early visual cortical representations and can be more effectively exploited in stimulus identification than hand-designed Gabor wavelets. Our results demonstrate the potential of our approach to better probe unknown cortical representations. PMID:25101625

  4. Nondestructive evaluation technique using infrared thermography and terahertz imaging

    NASA Astrophysics Data System (ADS)

    Sakagami, Takahide; Shiozawa, Daiki; Tamaki, Yoshitaka; Iwama, Tatsuya

    2016-05-01

    Nondestructive testing (NDT) techniques using pulse heating infrared thermography and terahertz (THz) imaging were developed for detecting deterioration of oil tank floor, such as blister and delamination of corrosion protection coating, or corrosion of the bottom steel plate under coating. Experimental studies were conducted to demonstrate the practicability of developed techniques. It was found that the pulse heating infrared thermography was utilized for effective screening inspection and THz-TDS imaging technique performed well for the detailed inspection of coating deterioration and steel corrosion.

  5. Evaluation of sequential images for photogrammetrically point determination

    NASA Astrophysics Data System (ADS)

    Kowalczyk, M.

    2011-12-01

    Close range photogrammetry encounters many problems with reconstruction of objects three-dimensional shape. Relative orientation parameters of taken photos makes usually key role leading to right solution of this problem. Automation of technology process is hardly performed due to recorded scene complexity and configuration of camera positions. This configuration makes the process of joining photos into one set usually impossible automatically. Application of camcorder is the solution widely proposed in literature for support in 3D models creation. Main advantages of this tool are connected with large number of recorded images and camera positions. Exterior orientation changes barely between two neighboring frames. Those features of film sequence gives possibilities for creating models with basic algorithms, working faster and more robust, than with remotely taken photos. The first part of this paper presents results of experiments determining interior orientation parameters of some sets of frames, presenting three-dimensional test field. This section describes calibration repeatability of film frames taken from camcorder. It is important due to stability of interior camera geometric parameters. Parametric model of systematical errors was applied for correcting images. Afterwards a short film of the same test field had been taken for determination of check points group. This part has been done for controlling purposes of camera application in measurement tasks. Finally there are presented some results of experiments which compare determination of recorded object points in 3D space. In common digital photogrammetry, where separate photos are used, first levels of image pyramids are taken to connect with feature based matching. This complicated process creates a lot of emergencies, which can produce false detections of image similarities. In case of digital film camera, authors of publications avoid this dangerous step, going straightly to area based matching, aiming

  6. SU-E-I-73: Clinical Evaluation of CT Image Reconstructed Using Interior Tomography

    SciTech Connect

    Zhang, J; Ge, G; Winkler, M; Cong, W; Wang, G

    2014-06-01

    Purpose: Radiation dose reduction has been a long standing challenge in CT imaging of obese patients. Recent advances in interior tomography (reconstruction of an interior region of interest (ROI) from line integrals associated with only paths through the ROI) promise to achieve significant radiation dose reduction without compromising image quality. This study is to investigate the application of this technique in CT imaging through evaluating imaging quality reconstructed from patient data. Methods: Projection data were directly obtained from patients who had CT examinations in a Dual Source CT scanner (DSCT). Two detectors in a DSCT acquired projection data simultaneously. One detector provided projection data for full field of view (FOV, 50 cm) while another detectors provided truncated projection data for a FOV of 26 cm. Full FOV CT images were reconstructed using both filtered back projection and iterative algorithm; while interior tomography algorithm was implemented to reconstruct ROI images. For comparison reason, FBP was also used to reconstruct ROI images. Reconstructed CT images were evaluated by radiologists and compared with images from CT scanner. Results: The results show that the reconstructed ROI image was in excellent agreement with the truth inside the ROI, obtained from images from CT scanner, and the detailed features in the ROI were quantitatively accurate. Radiologists evaluation shows that CT images reconstructed with interior tomography met diagnosis requirements. Radiation dose may be reduced up to 50% using interior tomography, depending on patient size. Conclusion: This study shows that interior tomography can be readily employed in CT imaging for radiation dose reduction. It may be especially useful in imaging obese patients, whose subcutaneous tissue is less clinically relevant but may significantly increase radiation dose.

  7. Application of Computed Tomography Virtual Noncontrast Spectral Imaging in Evaluation of Hepatic Metastases: A Preliminary Study

    PubMed Central

    Tian, Shi-Feng; Liu, Ai-Lian; Liu, Jing-Hong; Sun, Mei-Yu; Wang, He-Qing; Liu, Yi-Jun

    2015-01-01

    Objective: The objective was to qualitatively and quantitatively evaluate hepatic metastases using computed tomography (CT) virtual noncontrast (VNC) spectral imaging in a retrospective analysis. Methods: Forty hepatic metastases patients underwent CT scans including the conventional true noncontrast (TNC) and the tri-phasic contrast-enhanced dual energy spectral scans in the hepatic arterial, portal venous, and equilibrium phases. The tri-phasic spectral CT images were used to obtain three groups of VNC images including in the arterial (VNCa), venous (VNCv), and equilibrium (VNCe) phase by the material decomposition process using water and iodine as a base material pair. The image quality and the contrast-to-noise ratio (CNR) of metastasis of the four groups were compared with ANOVA analysis. The metastasis detection rates with the four nonenhanced image groups were calculated and compared using the Chi-square test. Results: There were no significant differences in image quality among TNC, VNCa and VNCv images (P > 0.05). The quality of VNCe images was significantly worse than that of other three groups (P < 0.05). The mean CNR of metastasis in the TNC and VNCs images was 1.86, 2.42, 1.92, and 1.94, respectively; the mean CNR of metastasis in VNCa images was significantly higher than that in other three groups (P < 0.05), while no statistically significant difference was observed among VNCv, VNCe and TNC images (P > 0.05). The metastasis detection rate of the four nonenhanced groups with no statistically significant difference (P > 0.05). Conclusions: The quality of VNCa and VNCv images is identical to that of TNC images, and the metastasis detection rate in VNC images is similar to that in TNC images. VNC images obtained from arterial phase show metastases more clearly. Thus, VNCa imaging may be a surrogate to TNC imaging in hepatic metastasis diagnosis. PMID:25698191

  8. Evaluating Educational Programmes: The Need and the Response.

    ERIC Educational Resources Information Center

    Stake, Robert E.

    This survey of recent developments in educational program evaluation is intended for persons who commission, implement, direct, or carry out evaluation studies. The attitudes of government officials, educators, and researchers toward assessment and their own evaluation needs are discussed. Various approaches to evaluation are briefly described;…

  9. Development and evaluation of a Hadamard transform imaging spectrometer and a Hadamard transform thermal imager

    NASA Technical Reports Server (NTRS)

    Harwit, M.; Swift, R.; Wattson, R.; Decker, J.; Paganetti, R.

    1976-01-01

    A spectrometric imager and a thermal imager, which achieve multiplexing by the use of binary optical encoding masks, were developed. The masks are based on orthogonal, pseudorandom digital codes derived from Hadamard matrices. Spatial and/or spectral data is obtained in the form of a Hadamard transform of the spatial and/or spectral scene; computer algorithms are then used to decode the data and reconstruct images of the original scene. The hardware, algorithms and processing/display facility are described. A number of spatial and spatial/spectral images are presented. The achievement of a signal-to-noise improvement due to the signal multiplexing was also demonstrated. An analysis of the results indicates both the situations for which the multiplex advantage may be gained, and the limitations of the technique. A number of potential applications of the spectrometric imager are discussed.

  10. Evaluation of the possibility to use thick slabs of reconstructed outer breast tomosynthesis slice images

    NASA Astrophysics Data System (ADS)

    Petersson, Hannie; Dustler, Magnus; Tingberg, Anders; Timberg, Pontus

    2016-03-01

    The large image volumes in breast tomosynthesis (BT) have led to large amounts of data and a heavy workload for breast radiologists. The number of slice images can be decreased by combining adjacent image planes (slabbing) but the decrease in depth resolution can considerably affect the detection of lesions. The aim of this work was to assess if thicker slabbing of the outer slice images (where lesions seldom are present) could be a viable alternative in order to reduce the number of slice images in BT image volumes. The suggested slabbing (an image volume with thick outer slabs and thin slices between) were evaluated in two steps. Firstly, a survey of the depth of 65 cancer lesions within the breast was performed to estimate how many lesions would be affected by outer slabs of different thicknesses. Secondly, a selection of 24 lesions was reconstructed with 2, 6 and 10 mm slab thickness to evaluate how the appearance of lesions located in the thicker slabs would be affected. The results show that few malignant breast lesions are located at a depth less than 10 mm from the surface (especially for breast thicknesses of 50 mm and above). Reconstruction of BT volumes with 6 mm slab thickness yields an image quality that is sufficient for lesion detection for a majority of the investigated cases. Together, this indicates that thicker slabbing of the outer slice images is a promising option in order to reduce the number of slice images in BT image volumes.

  11. Preliminary investigation of the frequency response and distortion properties of nonlinear image processing algorithms

    NASA Astrophysics Data System (ADS)

    Wells, Jered R.; Dobbins, James T.

    2013-03-01

    Assessment of the resolution properties of nonlinear imaging systems is a useful but challenging task. While the modulation transfer function (MTF) fully describes contrast resolution as a function of spatial frequency for linear syst