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Sample records for fluoroscopic imaging technique

  1. Computerized tomography using video recorded fluoroscopic images

    NASA Technical Reports Server (NTRS)

    Kak, A. C.; Jakowatz, C. V., Jr.; Baily, N. A.; Keller, R. A.

    1977-01-01

    The use of video-recorded fluoroscopic images as input data for digital reconstruction of objects from their projections is examined. The fluoroscopic and the scanning apparatus used for the experiments are of a commercial type already in existence in most hospitals. It is shown that for beams with divergence up to about 15 deg, one can use a convolution algorithm designed for the parallel radiation case with negligible degradation both quantitatively and from a visual quality standpoint. This convolution algorithm is computationally more efficient than either the algebraic techniques or the convolution algorithms for radially diverging data. Results from studies on Lucite phantoms and a freshly sacrificed rat are included.

  2. Fluoroscopic studies of the upper gastrointestinal tract: techniques and indications.

    PubMed

    Sánchez-Carpintero de la Vega, M; García Villar, C

    2017-01-25

    Fluoroscopic studies of the gastrointestinal tract are becoming increasing less common due to the introduction of other imaging techniques such as computed tomography and magnetic resonance imaging and to the increased availability of endoscopy. Nevertheless, fluoroscopic studies of the gastrointestinal tract continue to appear in clinical guidelines and some of their indications are still valid. These studies are dynamic, operator-dependent examinations that require training to obtain the maximum diagnostic performance. This review aims to describe the technique and bring the indications for this imaging modality up to date.

  3. Computerized tomography using video recorded fluoroscopic images

    NASA Technical Reports Server (NTRS)

    Kak, A. C.; Jakowatz, C. V., Jr.; Baily, N. A.; Keller, R. A.

    1975-01-01

    A computerized tomographic imaging system is examined which employs video-recorded fluoroscopic images as input data. By hooking the video recorder to a digital computer through a suitable interface, such a system permits very rapid construction of tomograms.

  4. Fluoroscopic image-guided intervention system for transbronchial localization

    NASA Astrophysics Data System (ADS)

    Rai, Lav; Keast, Thomas M.; Wibowo, Henky; Yu, Kun-Chang; Draper, Jeffrey W.; Gibbs, Jason D.

    2012-02-01

    Reliable transbronchial access of peripheral lung lesions is desirable for the diagnosis and potential treatment of lung cancer. This procedure can be difficult, however, because accessory devices (e.g., needle or forceps) cannot be reliably localized while deployed. We present a fluoroscopic image-guided intervention (IGI) system for tracking such bronchoscopic accessories. Fluoroscopy, an imaging technology currently utilized by many bronchoscopists, has a fundamental shortcoming - many lung lesions are invisible in its images. Our IGI system aligns a digitally reconstructed radiograph (DRR) defined from a pre-operative computed tomography (CT) scan with live fluoroscopic images. Radiopaque accessory devices are readily apparent in fluoroscopic video, while lesions lacking a fluoroscopic signature but identifiable in the CT scan are superimposed in the scene. The IGI system processing steps consist of: (1) calibrating the fluoroscopic imaging system; (2) registering the CT anatomy with its depiction in the fluoroscopic scene; (3) optical tracking to continually update the DRR and target positions as the fluoroscope is moved about the patient. The end result is a continuous correlation of the DRR and projected targets with the anatomy depicted in the live fluoroscopic video feed. Because both targets and bronchoscopic devices are readily apparent in arbitrary fluoroscopic orientations, multiplane guidance is straightforward. The system tracks in real-time with no computational lag. We have measured a mean projected tracking accuracy of 1.0 mm in a phantom and present results from an in vivo animal study.

  5. Temporomandibular joint arthrography: a comparison between a fluoroscopic and a nonfluoroscopic technique

    SciTech Connect

    Benson, B.W.; Langlais, R.P.; Abramovitch, K.

    1989-05-01

    A nonfluoroscopic temporomandibular joint arthrographic technique is contrasted with a more widely employed fluoroscopically guided technique. The nonfluoroscopic technique uses a posterior approach to joint injection, as contrasted with the lateral injection approach of the fluoroscopically guided technique. The advantages of the nonfluoroscopic technique are less radiation dose to the patient, less expensive and less sophisticated imaging equipment, and less potential for neurovascular trauma. The fluoroscopic technique offers greater control of the procedure, less patient and operator time, and the capability for a dynamic videofluoroscopic study. Both techniques appear to be safe and efficacious. Differences in anatomy, imaging modalities, patient radiation exposure, and potential complications are also discussed as part of this comparison.48 references.

  6. Fluoroscopy: recording of fluoroscopic images and automatic exposure control.

    PubMed

    Geise, R A

    2001-01-01

    Some means of recording images is a necessary part of most fluoroscopic systems. Several methods are available for recording images during fluoroscopy. Screen-film recording methods such as use of spot film devices and automatic film changers provide high-spatial-resolution images. Recording images by using the image intensifier (fluorography) provides film or digital images at relatively lower doses but with poorer spatial resolution. Digitally recorded images have better contrast resolution than analog images but lower spatial resolution and represent a compromise between dose and image quality. Motion picture (cine fluorographic) recording requires extremely high dose rates compared with those of lower-resolution videotape recording of motion. Recording systems in fluoroscopy require automatic exposure control for optimum image quality. The same feedback system used to control fluorographic exposures can be used to control exposure rates during fluoroscopy as well. Automatic brightness control maintains intensifier exposure rates on the basis of subject thickness by adjusting various technique factors. The type of control mechanism depends on the imaging task and the complexity (age and cost) of the equipment. The operator can choose between better image quality (higher contrast) or lower radiation dose.

  7. Fluoroscopic tumor tracking for image-guided lung cancer radiotherapy

    NASA Astrophysics Data System (ADS)

    Lin, Tong; Cerviño, Laura I.; Tang, Xiaoli; Vasconcelos, Nuno; Jiang, Steve B.

    2009-02-01

    Accurate lung tumor tracking in real time is a keystone to image-guided radiotherapy of lung cancers. Existing lung tumor tracking approaches can be roughly grouped into three categories: (1) deriving tumor position from external surrogates; (2) tracking implanted fiducial markers fluoroscopically or electromagnetically; (3) fluoroscopically tracking lung tumor without implanted fiducial markers. The first approach suffers from insufficient accuracy, while the second may not be widely accepted due to the risk of pneumothorax. Previous studies in fluoroscopic markerless tracking are mainly based on template matching methods, which may fail when the tumor boundary is unclear in fluoroscopic images. In this paper we propose a novel markerless tumor tracking algorithm, which employs the correlation between the tumor position and surrogate anatomic features in the image. The positions of the surrogate features are not directly tracked; instead, we use principal component analysis of regions of interest containing them to obtain parametric representations of their motion patterns. Then, the tumor position can be predicted from the parametric representations of surrogates through regression. Four regression methods were tested in this study: linear and two-degree polynomial regression, artificial neural network (ANN) and support vector machine (SVM). The experimental results based on fluoroscopic sequences of ten lung cancer patients demonstrate a mean tracking error of 2.1 pixels and a maximum error at a 95% confidence level of 4.6 pixels (pixel size is about 0.5 mm) for the proposed tracking algorithm.

  8. 3D fluoroscopic image estimation using patient-specific 4DCBCT-based motion models

    PubMed Central

    Dhou, Salam; Hurwitz, Martina; Mishra, Pankaj; Cai, Weixing; Rottmann, Joerg; Li, Ruijiang; Williams, Christopher; Wagar, Matthew; Berbeco, Ross; Ionascu, Dan; Lewis, John H.

    2015-01-01

    3D fluoroscopic images represent volumetric patient anatomy during treatment with high spatial and temporal resolution. 3D fluoroscopic images estimated using motion models built using 4DCT images, taken days or weeks prior to treatment, do not reliably represent patient anatomy during treatment. In this study we develop and perform initial evaluation of techniques to develop patient-specific motion models from 4D cone-beam CT (4DCBCT) images, taken immediately before treatment, and use these models to estimate 3D fluoroscopic images based on 2D kV projections captured during treatment. We evaluate the accuracy of 3D fluoroscopic images by comparing to ground truth digital and physical phantom images. The performance of 4DCBCT- and 4DCT- based motion models are compared in simulated clinical situations representing tumor baseline shift or initial patient positioning errors. The results of this study demonstrate the ability for 4DCBCT imaging to generate motion models that can account for changes that cannot be accounted for with 4DCT-based motion models. When simulating tumor baseline shift and patient positioning errors of up to 5 mm, the average tumor localization error and the 95th percentile error in six datasets were 1.20 and 2.2 mm, respectively, for 4DCBCT-based motion models. 4DCT-based motion models applied to the same six datasets resulted in average tumor localization error and the 95th percentile error of 4.18 and 5.4 mm, respectively. Analysis of voxel-wise intensity differences was also conducted for all experiments. In summary, this study demonstrates the feasibility of 4DCBCT-based 3D fluoroscopic image generation in digital and physical phantoms, and shows the potential advantage of 4DCBCT-based 3D fluoroscopic image estimation when there are changes in anatomy between the time of 4DCT imaging and the time of treatment delivery. PMID:25905722

  9. 3D fluoroscopic image estimation using patient-specific 4DCBCT-based motion models.

    PubMed

    Dhou, S; Hurwitz, M; Mishra, P; Cai, W; Rottmann, J; Li, R; Williams, C; Wagar, M; Berbeco, R; Ionascu, D; Lewis, J H

    2015-05-07

    3D fluoroscopic images represent volumetric patient anatomy during treatment with high spatial and temporal resolution. 3D fluoroscopic images estimated using motion models built using 4DCT images, taken days or weeks prior to treatment, do not reliably represent patient anatomy during treatment. In this study we developed and performed initial evaluation of techniques to develop patient-specific motion models from 4D cone-beam CT (4DCBCT) images, taken immediately before treatment, and used these models to estimate 3D fluoroscopic images based on 2D kV projections captured during treatment. We evaluate the accuracy of 3D fluoroscopic images by comparison to ground truth digital and physical phantom images. The performance of 4DCBCT-based and 4DCT-based motion models are compared in simulated clinical situations representing tumor baseline shift or initial patient positioning errors. The results of this study demonstrate the ability for 4DCBCT imaging to generate motion models that can account for changes that cannot be accounted for with 4DCT-based motion models. When simulating tumor baseline shift and patient positioning errors of up to 5 mm, the average tumor localization error and the 95th percentile error in six datasets were 1.20 and 2.2 mm, respectively, for 4DCBCT-based motion models. 4DCT-based motion models applied to the same six datasets resulted in average tumor localization error and the 95th percentile error of 4.18 and 5.4 mm, respectively. Analysis of voxel-wise intensity differences was also conducted for all experiments. In summary, this study demonstrates the feasibility of 4DCBCT-based 3D fluoroscopic image generation in digital and physical phantoms and shows the potential advantage of 4DCBCT-based 3D fluoroscopic image estimation when there are changes in anatomy between the time of 4DCT imaging and the time of treatment delivery.

  10. 3D fluoroscopic image estimation using patient-specific 4DCBCT-based motion models

    NASA Astrophysics Data System (ADS)

    Dhou, S.; Hurwitz, M.; Mishra, P.; Cai, W.; Rottmann, J.; Li, R.; Williams, C.; Wagar, M.; Berbeco, R.; Ionascu, D.; Lewis, J. H.

    2015-05-01

    3D fluoroscopic images represent volumetric patient anatomy during treatment with high spatial and temporal resolution. 3D fluoroscopic images estimated using motion models built using 4DCT images, taken days or weeks prior to treatment, do not reliably represent patient anatomy during treatment. In this study we developed and performed initial evaluation of techniques to develop patient-specific motion models from 4D cone-beam CT (4DCBCT) images, taken immediately before treatment, and used these models to estimate 3D fluoroscopic images based on 2D kV projections captured during treatment. We evaluate the accuracy of 3D fluoroscopic images by comparison to ground truth digital and physical phantom images. The performance of 4DCBCT-based and 4DCT-based motion models are compared in simulated clinical situations representing tumor baseline shift or initial patient positioning errors. The results of this study demonstrate the ability for 4DCBCT imaging to generate motion models that can account for changes that cannot be accounted for with 4DCT-based motion models. When simulating tumor baseline shift and patient positioning errors of up to 5 mm, the average tumor localization error and the 95th percentile error in six datasets were 1.20 and 2.2 mm, respectively, for 4DCBCT-based motion models. 4DCT-based motion models applied to the same six datasets resulted in average tumor localization error and the 95th percentile error of 4.18 and 5.4 mm, respectively. Analysis of voxel-wise intensity differences was also conducted for all experiments. In summary, this study demonstrates the feasibility of 4DCBCT-based 3D fluoroscopic image generation in digital and physical phantoms and shows the potential advantage of 4DCBCT-based 3D fluoroscopic image estimation when there are changes in anatomy between the time of 4DCT imaging and the time of treatment delivery.

  11. 21 CFR 892.1650 - Image-intensified fluoroscopic x-ray system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Image-intensified fluoroscopic x-ray system. 892... fluoroscopic x-ray system. (a) Identification. An image-intensified fluoroscopic x-ray system is a device intended to visualize anatomical structures by converting a pattern of x-radiation into a visible image...

  12. 21 CFR 892.1660 - Non-image-intensified fluoroscopic x-ray system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Non-image-intensified fluoroscopic x-ray system... fluoroscopic x-ray system. (a) Identification. A non-image-intensified fluoroscopic x-ray system is a device... of x-radiation into a visible image. This generic type of device may include signal analysis and...

  13. FLUOROSCOPIC EVALUATION OF ORO-PHARYNGEAL DYSPHAGIA: ANATOMY, TECHNIQUE, AND COMMON ETIOLOGIES

    PubMed Central

    Edmund, Dr; Au, Frederick Wing-Fai; Steele, Catriona M.

    2015-01-01

    Target Audience Radiologists and other professionals involved in imaging of oropharyngeal swallowing Objectives To review anatomy of the upper GI tract To review techniques and contrast agents used in the fluoroscopic examination of the oropharynx and hypopharynx To provide a pictorial review of some important causes of oropharyngeal dysphagia, and to link these to key findings in the clinical history to assist in establishing a clinical diagnosis To provide self-assessment questions to reinforce key learning points PMID:25539237

  14. Image-guided transapical aortic valve implantation: sensorless tracking of stenotic valve landmarks in live fluoroscopic images.

    PubMed

    Merk, Denis R; Karar, Mohamed Esmail; Chalopin, Claire; Holzhey, David; Falk, Volkmar; Mohr, Friedrich W; Burgert, Oliver

    2011-07-01

    Aortic valve stenosis is one of the most frequently acquired valvular heart diseases, accounting for almost 70% of valvular cardiac surgery. Transapical transcatheter aortic valve implantation has recently become a suitable minimally invasive technique for high-risk and elderly patients with severe aortic stenosis. In this article, we aim to automatically define a target area of valve implantation, namely, the area between the coronary ostia and the lowest points of two aortic valve cusps. Therefore, we present a new image-based tracking method of these aortic landmarks to assist in the placement of aortic valve prosthesis under live 2D fluoroscopy guidance. We propose a rigid intensity-based image registration technique for tracking valve landmarks in 2D fluoroscopic image sequences, based on a real-time alignment of a contrast image including the initialized manual valve landmarks to each image of sequence. The contrast image is automatically detected to visualize aortic valve features when the aortic root is filled with a contrast agent. Our registration-based tracking method has been retrospectively applied to 10 fluoroscopic image sequences from routine transapical aortic valve implantation procedures. Most of all tested fluoroscopic images showed a successful tracking of valve landmarks, especially for the images without contrast agent injections. A new intraoperative image-based method has been developed for tracking aortic valve landmarks in live 2D fluoroscopic images to assist transapical aortic valve implantations and to increase the overall safety of surgery as well.

  15. MR cone-beam CT fusion image overlay for fluoroscopically guided percutaneous biopsies in pediatric patients.

    PubMed

    Thakor, Avnesh S; Patel, Premal A; Gu, Richard; Rea, Vanessa; Amaral, Joao; Connolly, Bairbre L

    2016-03-01

    Lesions only visible on magnetic resonance (MR) imaging cannot easily be targeted for image-guided biopsy using ultrasound or X-rays but instead require MR guidance with MR-compatible needles and long procedure times (acquisition of multiple MR sequences). We developed an alternative method for performing these difficult biopsies in a standard interventional suite, by fusing MR with cone-beam CT images. The MR cone-beam CT fusion image is then used as an overlay to guide a biopsy needle to the target area under live fluoroscopic guidance. Advantages of this technique include (i) the ability for it to be performed in a conventional interventional suite, (ii) three-dimensional planning of the needle trajectory using cross-sectional imaging, (iii) real-time fluoroscopic guidance for needle trajectory correction and (iv) targeting within heterogeneous lesions based on MR signal characteristics to maximize the potential biopsy yield.

  16. A novel marker enhancement filter (MEF) for fluoroscopic images

    NASA Astrophysics Data System (ADS)

    Peshko, Olesya; Davidson, Timothy N.; Modersitzki, Jan; Terlaky, Tamás; Moseley, Douglas J.

    2014-03-01

    To enhance the measurements of radio-opaque cylindrical fiducial markers in low contrast x-ray and fluoroscopic images, a novel nonlinear marker enhancement filter (MEF) has been designed. It was primarily developed to assist in automatic initialization of a tracking procedure for intra-fraction organ motion analysis in fluoroscopic sequences. Conventional procedures were not able to provide sufficient improvement due to the complications of noise, small marker size, cylindrical shape and multiple orientations, intensity variations of the background, and the presence of overlaying anatomical measurements in this application. The proposed MEF design is based on the principles of linear scale space. It includes measures that assess the probability of each pixel to belong to a marker measurement, morphological operations, and a novel contrast enhancement function for standardization of the filter output. The MEF was tested on fluoroscopic images of two phantoms and three prostate patients, and was shown to perform better or comparable to the existing filters in terms of marker enhancement and background suppression, while performing significantly better in marker shape preservation.

  17. Cryo-balloon catheter localization in fluoroscopic images

    NASA Astrophysics Data System (ADS)

    Kurzendorfer, Tanja; Brost, Alexander; Jakob, Carolin; Mewes, Philip W.; Bourier, Felix; Koch, Martin; Kurzidim, Klaus; Hornegger, Joachim; Strobel, Norbert

    2013-03-01

    Minimally invasive catheter ablation has become the preferred treatment option for atrial fibrillation. Although the standard ablation procedure involves ablation points set by radio-frequency catheters, cryo-balloon catheters have even been reported to be more advantageous in certain cases. As electro-anatomical mapping systems do not support cryo-balloon ablation procedures, X-ray guidance is needed. However, current methods to provide support for cryo-balloon catheters in fluoroscopically guided ablation procedures rely heavily on manual user interaction. To improve this, we propose a first method for automatic cryo-balloon catheter localization in fluoroscopic images based on a blob detection algorithm. Our method is evaluated on 24 clinical images from 17 patients. The method successfully detected the cryoballoon in 22 out of 24 images, yielding a success rate of 91.6 %. The successful localization achieved an accuracy of 1.00 mm +/- 0.44 mm. Even though our methods currently fails in 8.4 % of the images available, it still offers a significant improvement over manual methods. Furthermore, detecting a landmark point along the cryo-balloon catheter can be a very important step for additional post-processing operations.

  18. SU-E-P-15: Technique Factor Modulation and Reference Plane Air Kerma Rates in Response to Simulated Patient Thickness Variations for a Sample of Current Generation Fluoroscopes

    SciTech Connect

    Wunderle, K; Rakowski, J; Dong, F

    2015-06-15

    Purpose: To evaluate and compare approaches to technique factor modulation and air kerma rates in response to simulated patient thickness variations for four state-of-the-art and one previous-generation interventional fluoroscopes. Methods: A polymethyl methacrylate (PMMA) phantom was used as a tissue surrogate for the purposes of determining fluoroscopic reference plane air kerma rates, kVp, mA, and spectral filtration over a wide range of simulated tissue thicknesses. Data were acquired for each fluoroscopic and acquisition dose curve within a default abdomen or body imaging protocol. Results: The data obtained indicated vendor- and model-specific variations in the approach to technique factor modulation and reference plane air kerma rates across a range of tissue thicknesses. Some vendors have made hardware advances increasing the radiation output capabilities of their fluoroscopes; this was evident in the acquisition air kerma rates. However, in the imaging protocol evaluated, all of the state-of-the-art systems had relatively low air kerma rates in the fluoroscopic low-dose imaging mode as compared to the previous-generation unit. Each of the newest-generation systems also employ copper filtration in the selected protocol in the acquisition mode of imaging; this is a substantial benefit, reducing the skin entrance dose to the patient in the highest dose-rate mode of fluoroscope operation. Conclusion: Understanding how fluoroscopic technique factors are modulated provides insight into the vendor-specific image acquisition approach and provides opportunities to optimize the imaging protocols for clinical practice. The enhanced radiation output capabilities of some of the fluoroscopes may, under specific conditions, may be beneficial; however, these higher output capabilities also have the potential to lead to unnecessarily high dose rates. Therefore, all parties involved in imaging, including the clinical team, medical physicists, and imaging vendors, must work

  19. 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.

  20. Simulation system for understanding the lag effect in fluoroscopic images.

    PubMed

    Tanaka, Rie; Kawashima, Hiroki; Ichikawa, Katsuhiro; Matsubara, Kosuke; Iida, Hiroji; Sanada, Shigeru

    2013-07-01

    Real-time tumor tracking in external radiotherapy can be achieved by diagnostic (kV) X-ray imaging with a dynamic flat-panel detector (FPD). It is crucial to understand the effects of image lag for real-time tumor tracking. Our purpose in this study was to develop a lag simulation system based on the image lag properties of an FPD system. Image lag properties were measured on flat-field images both in direct- and indirect-conversion dynamic FPDs. A moving target with image lag was simulated based on the lag properties in all combinations of FPD types, imaging rates, exposure doses, and target speeds, and then compared with actual moving targets for investigation of the reproducibility of image lag. Image lag was simulated successfully and agreed well with the actual lag as well as with the predicted effect. In the indirect-conversion FPD, a higher dose caused greater image lag on images. In contrast, there were no significant differences among dose levels in a direct-conversion FPD. There were no relationships between target speed and amount of image blurring in either type of FPD. The maximum contour blurring and the rate of increase in pixel value due to image lag were 1.1 mm and 10.0 %, respectively, in all combinations of imaging parameters examined in this study. Blurred boundaries and changes in pixel value due to image lag were estimated under various imaging conditions with use of the simulation system. Our system would be helpful for a better understanding of the effects of image lag in fluoroscopic images.

  1. Dynamic imaging of pulmonary ventilation. Description of a novel digital fluoroscopic system.

    PubMed

    Kiuru, A; Svedström, E; Kuuluvainen, I

    1991-03-01

    A new fluoroscopic imaging device consisting of an AT-microcomputer and a digital image memory unit has been used in experimental and clinical ventilation studies during a 2-year period. Digital images with 256 shades of gray were collected during one to 3 ventilation cycles at the rate of 6 to 25 images/s and stored on an optical laser disc. Both subtracted time interval difference (TID-) images and images relative, for example, to the mean image of the cycle (REL-images) were produced. The series of images could also be evaluated dynamically using animation sequences or analyzed using region of interest calculations. The method gave dynamic information with adequate spatial resolution and was easy to use in clinical practice. The radiation dose was kept low due to the high kilovoltage and heavy beam filtration technique. In experimental studies the software enabled flexible measurements of physiological pulmonary parameters.

  2. Auto-shape lossless compression of pharynx and esophagus fluoroscopic images.

    PubMed

    Arif, Arif Sameh; Mansor, Sarina; Logeswaran, Rajasvaran; Karim, Hezerul Abdul

    2015-02-01

    The massive number of medical images produced by fluoroscopic and other conventional diagnostic imaging devices demand a considerable amount of space for data storage. This paper proposes an effective method for lossless compression of fluoroscopic images. The main contribution in this paper is the extraction of the regions of interest (ROI) in fluoroscopic images using appropriate shapes. The extracted ROI is then effectively compressed using customized correlation and the combination of Run Length and Huffman coding, to increase compression ratio. The experimental results achieved show that the proposed method is able to improve the compression ratio by 400 % as compared to that of traditional methods.

  3. Solid-state fluoroscopic imager for high-resolution angiography: Parallel-cascaded linear systems analysis

    PubMed Central

    Vedantham, Srinivasan; Karellas, Andrew; Suryanarayanan, Sankararaman

    2008-01-01

    Cascaded linear systems based modeling techniques have been used in the past to predict important system parameters that have a direct impact on image quality. Such models are also useful in optimizing system parameters to improve image quality. In this work, detailed analysis of a solid-state fluoroscopic imaging system intended for high-resolution angiography is presented with the use of such a model. The imaging system analyzed through this model uses four 8×8 cm three-side buttable interlined charge-coupled devices (CCDs) specifically designed for high-resolution angiography and tiled in a seamless fashion to achieve a field of view (FOV) of 16×16 cm. Larger FOVs can be achieved by tiling more CCDs in a similar manner. The system employs a CsI:Tl scintillator coupled to the CCDs by straight (nontapering) fiberoptics and can potentially be operated in 78, 156, or 234 μm pixel pitch modes. The system parameters analyzed through this model include presampling modulation transfer function, noise power spectrum, and detective quantum efficiency (DQE). The results of the simulations performed indicate that DQE(0) in excess of 0.6 is achievable, with the imager operating at 156 μm pixel pitch, 30 frames/s, and employing a 450-μm-thick CsI:Tl scintillator, even at a low fluoroscopic exposure rate of 1 μR/frame. Further, at a nominal fluoroscopic exposure rate of 2.5 μR/frame there was no noticeable degradation of the DQE even at the 78 μm pixel pitch mode suggesting that it is feasible to perform high-resolution angiography hitherto unattainable in clinical practice. PMID:15191318

  4. Solid-state fluoroscopic imager for high-resolution angiography: parallel-cascaded linear systems analysis.

    PubMed

    Vedantham, Srinivasan; Karellas, Andrew; Suryanarayanan, Sankararaman

    2004-05-01

    Cascaded linear systems based modeling techniques have been used in the past to predict important system parameters that have a direct impact on image quality. Such models are also useful in optimizing system parameters to improve image quality. In this work, detailed analysis of a solid-state fluoroscopic imaging system intended for high-resolution angiography is presented with the use of such a model. The imaging system analyzed through this model uses four 8 x 8 cm three-side buttable interlined charge-coupled devices (CCDs) specifically designed for high-resolution angiography and tiled in a seamless fashion to achieve a field of view (FOV) of 16 x 16 cm. Larger FOVs can be achieved by tiling more CCDs in a similar manner. The system employs a CsI:Tl scintillator coupled to the CCDs by straight (nontapering) fiberoptics and can potentially be operated in 78, 156, or 234 microm pixel pitch modes. The system parameters analyzed through this model include presampling modulation transfer function, noise power spectrum, and detective quantum efficiency (DQE). The results of the simulations performed indicate that DQE(0) in excess of 0.6 is achievable, with the imager operating at 156 microm pixel pitch, 30 frames/s, and employing a 450-microm-thick CsI:Tl scintillator, even at a low fluoroscopic exposure rate of 1 microR/frame. Further, at a nominal fluoroscopic exposure rate of 2.5 microR/frame there was no noticeable degradation of the DQE even at the 78 microm pixel pitch mode suggesting that it is feasible to perform high-resolution angiography hitherto unattainable in clinical practice.

  5. Percutaneous Radiofrequency Thermocoagulation Under Fluoroscopic Image-Guidance for Idiopathic Trigeminal Neuralgia

    PubMed Central

    Kim, Hyung-Suk; Kim, Il-Sup; Yang, Seung-Ho; Lee, Sang-Won

    2011-01-01

    Objective We retrospectively investigated the long-term results of percutaneous radiofrequency thermocoagulation (RFT) using fluoroscopic image-guidance for treatment of trigeminal neuralgia. Methods A total of 38 patients diagnosed and treated with RFT as an idiopathic trigeminal neuralgia were investigated. To minimize the risks related to conventional technique based on cutaneous landmarks, and to eliminate the need to frequent reposition of cannula, we adopted a technique of image-guided fluoroscopic cannulation of the foramen ovale. To minimize sensory complication following thermal lesion, our target response was a generation of a lesion with mild to moderate hypalgesia rather than dense hypalgesia. Results The immediate pain-relief was achieved in all patients underwent RFT. With mean duration of follow-up of 38.2 months (range,12-72), 11 (28.9%) experienced recurrence of pain. The mean timing of recurrence was 26.1 months (range,12-46). A 42.7% recurrence rate was estimated by Kaplan-Meier analysis for the 38 patients at 46 months; 20.2% within 2 years, 29.1% within 3 years. In the long-term, 27 patients (71%) and 6 patients (15.8%) showed Barrow Neurological Institute (BNI) score I and BNI score II responses. 3 (7.9%) patients was assessed as BNI score III, 2 patients (5.3%) showed BNI score IV response. As a complication, troublesome dysesthesia occurred in 3 of 38 patients (7.9%), however, there was no permanent cranial nerve palsy or morbidity. Conclusion These results indicates that RFT under fluoroscopic image-guided cannulation of foramen ovale is a safe, effective, and reliable means of treating trigeminal neuralgia. PMID:22259692

  6. Multiresolution parametric estimation of transparent motions and denoising of fluoroscopic images.

    PubMed

    Auvray, Vincent; Liénard, Jean; Bouthemy, Patrick

    2005-01-01

    We describe a novel multiresolution parametric framework to estimate transparent motions typically present in X-Ray exams. Assuming the presence if two transparent layers, it computes two affine velocity fields by minimizing an appropriate objective function with an incremental Gauss-Newton technique. We have designed a realistic simulation scheme of fluoroscopic image sequences to validate our method on data with ground truth and different levels of noise. An experiment on real clinical images is also reported. We then exploit this transparent-motion estimation method to denoise two layers image sequences using a motion-compensated estimation method. In accordance with theory, we show that we reach a denoising factor of 2/3 in a few iterations without bringing any local artifacts in the image sequence.

  7. Technique for Percutaneous Fluoroscopically Guided G-Tube Placement in a High-BMI Patient.

    PubMed

    Best, Irwin M

    2012-01-01

    Enteral feeding is still the preferred method of nutritional support even in patients with excessive body mass index. Often, this mass poses a hindrance in performing routine procedures. We present a case describing the technique used to safely place a fluoroscopically guided G-tube in a patient with a significant nutritional deficit after repair of a ruptured thoracic aneurysm. Her admission weight was in excess of 180 Kg. However, protracted respiratory insufficiency and mechanical ventilation prolonged her hospital course. The G-tube was successfully placed using a fluoroscopically guided technique. The advantages of such an approach are discussed.

  8. Preoperative templating before spinal fusion using a fluoroscopic multiplanar imaging system is as accurate as CT scan and uses substantially less radiation.

    PubMed

    Kepler, Christopher K; Pavlov, Helene; Kim, Han J; Green, Daniel W; Rawlins, Bernard A

    2012-12-01

    Many surgeons utilize preoperative multiplanar imaging for surgical planning before fusion surgery using pedicle screw instrumentation. Computed tomographic (CT) scan is often used but limited by non-weight-bearing images and high-ionizing radiation. The purpose of this study was to compare pedicle length and width measurements using a multiplanar fluoroscopic imaging system and CT with gross measurements to validate the accuracy of multiplanar fluoroscopic imaging and compare relative radiation exposure between techniques. Thirteen intact cadaveric lumbar spine segments were imaged using multiplanar fluoroscopic imaging and conventional CT scan using a low-dose pediatric protocol. At each level and each imaging modality, the 26 pedicles were measured digitally for width and pedicle screw length in accordance with typical presurgical planning procedures. All images were independently measured by 3 observers. After measurement, the specimens were sectioned using a microsurgical saw to facilitate anatomic measurements using calipers. Measurements of the multiplanar fluoroscopic imaging and CT were compared with direct anatomic measurements to quantitate and compare measurement accuracy of CT and fluoroscopic imaging. At the time of image acquisition, radiation exposure from each modality was quantified to allow for comparison of radiation exposures. CT and multiplanar fluoroscopy had similar agreement with gross measurements with respect to pedicle width and length, with κ values for comparison of CT and fluoroscopy with gross measurements falling between 0.61 and 0.73. Both modalities underestimated pedicle width (by 1.9 mm for both modalities) and length (5.5 mm for CT, 6.6 mm for fluoroscopy). Interobserver reliability was higher for fluoroscopy versus CT. High-dose fluoroscopic imaging used 31% of the radiation exposure for CT. Multiplanar fluoroscopic imaging provides comparable diagnostic preoperative planning to CT scan in an experimental cadaveric model. The

  9. Toward Simultaneous Real-Time Fluoroscopic and Nuclear Imaging in the Intervention Room.

    PubMed

    Beijst, Casper; Elschot, Mattijs; Viergever, Max A; de Jong, Hugo W A M

    2016-01-01

    To investigate the technical feasibility of hybrid simultaneous fluoroscopic and nuclear imaging. An x-ray tube, an x-ray detector, and a gamma camera were positioned in one line, enabling imaging of the same field of view. Since a straightforward combination of these elements would block the lines of view, a gamma camera setup was developed to be able to view around the x-ray tube. A prototype was built by using a mobile C-arm and a gamma camera with a four-pinhole collimator. By using the prototype, test images were acquired and sensitivity, resolution, and coregistration error were analyzed. Nuclear images (two frames per second) were acquired simultaneously with fluoroscopic images. Depending on the distance from point source to detector, the system resolution was 1.5-1.9-cm full width at half maximum, the sensitivity was (0.6-1.5) × 10(-5) counts per decay, and the coregistration error was -0.13 to 0.15 cm. With good spatial and temporal alignment of both modalities throughout the field of view, fluoroscopic images can be shown in grayscale and corresponding nuclear images in color overlay. Measurements obtained with the hybrid imaging prototype device that combines simultaneous fluoroscopic and nuclear imaging of the same field of view have demonstrated the feasibility of real-time simultaneous hybrid imaging in the intervention room. © RSNA, 2015

  10. Accurate 3D kinematic measurement of temporomandibular joint using X-ray fluoroscopic images

    NASA Astrophysics Data System (ADS)

    Yamazaki, Takaharu; Matsumoto, Akiko; Sugamoto, Kazuomi; Matsumoto, Ken; Kakimoto, Naoya; Yura, Yoshiaki

    2014-04-01

    Accurate measurement and analysis of 3D kinematics of temporomandibular joint (TMJ) is very important for assisting clinical diagnosis and treatment of prosthodontics and orthodontics, and oral surgery. This study presents a new 3D kinematic measurement technique of the TMJ using X-ray fluoroscopic images, which can easily obtain the TMJ kinematic data in natural motion. In vivo kinematics of the TMJ (maxilla and mandibular bone) is determined using a feature-based 2D/3D registration, which uses beads silhouette on fluoroscopic images and 3D surface bone models with beads. The 3D surface models of maxilla and mandibular bone with beads were created from CT scans data of the subject using the mouthpiece with the seven strategically placed beads. In order to validate the accuracy of pose estimation for the maxilla and mandibular bone, computer simulation test was performed using five patterns of synthetic tantalum beads silhouette images. In the clinical applications, dynamic movement during jaw opening and closing was conducted, and the relative pose of the mandibular bone with respect to the maxilla bone was determined. The results of computer simulation test showed that the root mean square errors were sufficiently smaller than 1.0 mm and 1.0 degree. In the results of clinical application, during jaw opening from 0.0 to 36.8 degree of rotation, mandibular condyle exhibited 19.8 mm of anterior sliding relative to maxillary articular fossa, and these measurement values were clinically similar to the previous reports. Consequently, present technique was thought to be suitable for the 3D TMJ kinematic analysis.

  11. Automated detection of BB pixel clusters in digital fluoroscopic images

    NASA Astrophysics Data System (ADS)

    Cho, Paul S.; Johnson, Roger H.

    1998-09-01

    Small ball bearings (BBs) are often used to characterize and correct for geometric distortion of x-ray image intensifiers. For quantitative applications the number of BBs required for accurate distortion correction is prohibitively large for manual detection. A method to automatically determine the BB coordinates is described. The technique consists of image segmentation, pixel coalescing and centroid calculation. The dependence of calculated BB coordinates on segmentation threshold was also evaluated and found to be within the uncertainty of measurement.

  12. X-ray dose reduction through adaptive exposure in fluoroscopic imaging.

    PubMed

    Burion, Steve; Funk, Tobias

    2011-09-11

    X-ray fluoroscopy is widely used for image guidance during cardiac intervention. However, radiation dose in these procedures can be high, and this is a significant concern, particularly in pediatric applications. Pediatrics procedures are in general much more complex than those performed on adults and thus are on average four to eight times longer. Furthermore, children can undergo up to 10 fluoroscopic procedures by the age of 10, and have been shown to have a three-fold higher risk of developing fatal cancer throughout their life than the general population. We have shown that radiation dose can be significantly reduced in adult cardiac procedures by using our scanning beam digital x-ray (SBDX) system-- a fluoroscopic imaging system that employs an inverse imaging geometry (Figure 1, Movie 1 and Figure 2). Instead of a single focal spot and an extended detector as used in conventional systems, our approach utilizes an extended X-ray source with multiple focal spots focused on a small detector. Our X-ray source consists of a scanning electron beam sequentially illuminating up to 9,000 focal spot positions. Each focal spot projects a small portion of the imaging volume onto the detector. In contrast to a conventional system where the final image is directly projected onto the detector, the SBDX uses a dedicated algorithm to reconstruct the final image from the 9,000 detector images. For pediatric applications, dose savings with the SBDX system are expected to be smaller than in adult procedures. However, the SBDX system allows for additional dose savings by implementing an electronic adaptive exposure technique. Key to this method is the multi-beam scanning technique of the SBDX system: rather than exposing every part of the image with the same radiation dose, we can dynamically vary the exposure depending on the opacity of the region exposed. Therefore, we can significantly reduce exposure in radiolucent areas and maintain exposure in more opaque regions. In our

  13. 21 CFR 892.1650 - Image-intensified fluoroscopic x-ray system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Image-intensified fluoroscopic x-ray system. 892.1650 Section 892.1650 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1650...

  14. 21 CFR 892.1660 - Non-image-intensified fluoroscopic x-ray system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Non-image-intensified fluoroscopic x-ray system. 892.1660 Section 892.1660 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1660...

  15. 21 CFR 892.1650 - Image-intensified fluoroscopic x-ray system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Image-intensified fluoroscopic x-ray system. 892.1650 Section 892.1650 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1650...

  16. 21 CFR 892.1650 - Image-intensified fluoroscopic x-ray system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Image-intensified fluoroscopic x-ray system. 892.1650 Section 892.1650 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1650...

  17. 21 CFR 892.1650 - Image-intensified fluoroscopic x-ray system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Image-intensified fluoroscopic x-ray system. 892.1650 Section 892.1650 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1650...

  18. 21 CFR 892.1660 - Non-image-intensified fluoroscopic x-ray system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Non-image-intensified fluoroscopic x-ray system. 892.1660 Section 892.1660 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1660...

  19. 21 CFR 892.1660 - Non-image-intensified fluoroscopic x-ray system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Non-image-intensified fluoroscopic x-ray system. 892.1660 Section 892.1660 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1660...

  20. 21 CFR 892.1660 - Non-image-intensified fluoroscopic x-ray system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Non-image-intensified fluoroscopic x-ray system. 892.1660 Section 892.1660 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1660...

  1. Simultaneous fluoroscopic and nuclear imaging: impact of collimator choice on nuclear image quality.

    PubMed

    van der Velden, Sandra; Beijst, Casper; Viergever, Max A; de Jong, Hugo W A M

    2017-01-01

    X-ray-guided oncological interventions could benefit from the availability of simultaneously acquired nuclear images during the procedure. To this end, a real-time, hybrid fluoroscopic and nuclear imaging device, consisting of an X-ray c-arm combined with gamma imaging capability, is currently being developed (Beijst C, Elschot M, Viergever MA, de Jong HW. Radiol. 2015;278:232-238). The setup comprises four gamma cameras placed adjacent to the X-ray tube. The four camera views are used to reconstruct an intermediate three-dimensional image, which is subsequently converted to a virtual nuclear projection image that overlaps with the X-ray image. The purpose of the present simulation study is to evaluate the impact of gamma camera collimator choice (parallel hole versus pinhole) on the quality of the virtual nuclear image. Simulation studies were performed with a digital image quality phantom including realistic noise and resolution effects, with a dynamic frame acquisition time of 1 s and a total activity of 150 MBq. Projections were simulated for 3, 5, and 7 mm pinholes and for three parallel hole collimators (low-energy all-purpose (LEAP), low-energy high-resolution (LEHR) and low-energy ultra-high-resolution (LEUHR)). Intermediate reconstruction was performed with maximum likelihood expectation-maximization (MLEM) with point spread function (PSF) modeling. In the virtual projection derived therefrom, contrast, noise level, and detectability were determined and compared with the ideal projection, that is, as if a gamma camera were located at the position of the X-ray detector. Furthermore, image deformations and spatial resolution were quantified. Additionally, simultaneous fluoroscopic and nuclear images of a sphere phantom were acquired with a physical prototype system and compared with the simulations. For small hot spots, contrast is comparable for all simulated collimators. Noise levels are, however, 3 to 8 times higher in pinhole geometries than in parallel

  2. X-ray characterization of CMOS imaging detector with high resolution for fluoroscopic imaging application

    NASA Astrophysics Data System (ADS)

    Cha, Bo Kyung; Kim, Cho Rong; Jeon, Seongchae; Kim, Ryun Kyung; Seo, Chang-Woo; Yang, Keedong; Heo, Duchang; Lee, Tae-Bum; Shin, Min-Seok; Kim, Jong-Boo; Kwon, Oh-Kyung

    2013-12-01

    This paper introduces complementary metal-oxide semiconductor (CMOS) active pixel sensor (APS)-based X-ray imaging detectors with high spatial resolution for medical imaging application. In this study, our proposed X-ray CMOS imaging sensor has been fabricated by using a 0.35 μm 1 Poly 4 Metal CMOS process. The pixel size is 100 μm×100 μm and the pixel array format is 24×96 pixels, which provide a field-of-view (FOV) of 9.6 mm×2.4 mm. The 14.3-bit extend counting analog-to digital converter (ADC) with built-in binning mode was used to reduce the area and simultaneously improve the image resolution. Both thallium-doped CsI (CsI:Tl) and Gd2O2S:Tb scintillator screens were used as converters for incident X-rays to visible light photons. The optical property and X-ray imaging characterization such as X-ray to light response as a function of incident X-ray exposure dose, spatial resolution and X-ray images of objects were measured under different X-ray energy conditions. The measured results suggest that our developed CMOS-based X-ray imaging detector has the potential for fluoroscopic imaging and cone-beam computed tomography (CBCT) imaging applications.

  3. Nonrigid 2D registration of fluoroscopic coronary artery image sequence with layered motion

    NASA Astrophysics Data System (ADS)

    Park, Taewoo; Jung, Hoyup; Yun, Il Dong

    2016-03-01

    We present a new method for nonrigid registration of coronary artery models with layered motion information. 2D nonrigid registration method is proposed that brings layered motion information into correspondence with fluoroscopic angiograms. The registered model is overlaid on top of interventional angiograms to provide surgical assistance during image-guided chronic total occlusion procedures. The proposed methodology is divided into two parts: layered structures alignments and local nonrigid registration. In the first part, inpainting method is used to estimate a layered rigid transformation that aligns layered motion information. In the second part, a nonrigid registration method is implemented and used to compensate for any local shape discrepancy. Experimental evaluation conducted on a set of 7 fluoroscopic angiograms results in a reduced target registration error, which showed the effectiveness of the proposed method over single layered approach.

  4. 4DCBCT-based motion modeling and 3D fluoroscopic image generation for lung cancer radiotherapy

    NASA Astrophysics Data System (ADS)

    Dhou, Salam; Hurwitz, Martina; Mishra, Pankaj; Berbeco, Ross; Lewis, John

    2015-03-01

    A method is developed to build patient-specific motion models based on 4DCBCT images taken at treatment time and use them to generate 3D time-varying images (referred to as 3D fluoroscopic images). Motion models are built by applying Principal Component Analysis (PCA) on the displacement vector fields (DVFs) estimated by performing deformable image registration on each phase of 4DCBCT relative to a reference phase. The resulting PCA coefficients are optimized iteratively by comparing 2D projections captured at treatment time with projections estimated using the motion model. The optimized coefficients are used to generate 3D fluoroscopic images. The method is evaluated using anthropomorphic physical and digital phantoms reproducing real patient trajectories. For physical phantom datasets, the average tumor localization error (TLE) and (95th percentile) in two datasets were 0.95 (2.2) mm. For digital phantoms assuming superior image quality of 4DCT and no anatomic or positioning disparities between 4DCT and treatment time, the average TLE and the image intensity error (IIE) in six datasets were smaller using 4DCT-based motion models. When simulating positioning disparities and tumor baseline shifts at treatment time compared to planning 4DCT, the average TLE (95th percentile) and IIE were 4.2 (5.4) mm and 0.15 using 4DCT-based models, while they were 1.2 (2.2) mm and 0.10 using 4DCBCT-based ones, respectively. 4DCBCT-based models were shown to perform better when there are positioning and tumor baseline shift uncertainties at treatment time. Thus, generating 3D fluoroscopic images based on 4DCBCT-based motion models can capture both inter- and intra- fraction anatomical changes during treatment.

  5. A C-arm calibration method with application to fluoroscopic image-guided procedures

    NASA Astrophysics Data System (ADS)

    Rai, Lav; Gibbs, Jason D.; Wibowo, Henky

    2012-02-01

    C-arm fluoroscopy units provide continuously updating X-ray video images during surgical procedure. The modality is widely adopted for its low cost, real-time imaging capabilities, and its ability to display radio-opaque tools in the anatomy. It is, however, important to correct for fluoroscopic image distortion and estimate camera parameters, such as focal length and camera center, for registration with 3D CT scans in fluoroscopic imageguided procedures. This paper describes a method for C-arm calibration and evaluates its accuracy in multiple C-arm units and in different viewing orientations. The proposed calibration method employs a commerciallyavailable unit to track the C-arm and a calibration plate. The method estimates both the internal calibration parameters and the transformation between the coordinate systems of tracker and C-arm. The method was successfully tested on two C-arm units (GE OEC 9800 and GE OEC 9800 Plus) of different image intensifier sizes and verified with a rigid airway phantom model. The mean distortion-model error was found to be 0.14 mm and 0.17 mm for the respective C-arms. The mean overall system reprojection error (which measures the accuracy of predicting an image using tracker coordinates) was found to be 0.63 mm for the GE OEC 9800.

  6. Real-time image-processing algorithm for markerless tumour tracking using X-ray fluoroscopic imaging.

    PubMed

    Mori, S

    2014-05-01

    To ensure accuracy in respiratory-gating treatment, X-ray fluoroscopic imaging is used to detect tumour position in real time. Detection accuracy is strongly dependent on image quality, particularly positional differences between the patient and treatment couch. We developed a new algorithm to improve the quality of images obtained in X-ray fluoroscopic imaging and report the preliminary results. Two oblique X-ray fluoroscopic images were acquired using a dynamic flat panel detector (DFPD) for two patients with lung cancer. The weighting factor was applied to the DFPD image in respective columns, because most anatomical structures, as well as the treatment couch and port cover edge, were aligned in the superior-inferior direction when the patient lay on the treatment couch. The weighting factors for the respective columns were varied until the standard deviation of the pixel values within the image region was minimized. Once the weighting factors were calculated, the quality of the DFPD image was improved by applying the factors to multiframe images. Applying the image-processing algorithm produced substantial improvement in the quality of images, and the image contrast was increased. The treatment couch and irradiation port edge, which were not related to a patient's position, were removed. The average image-processing time was 1.1 ms, showing that this fast image processing can be applied to real-time tumour-tracking systems. These findings indicate that this image-processing algorithm improves the image quality in patients with lung cancer and successfully removes objects not related to the patient. Our image-processing algorithm might be useful in improving gated-treatment accuracy.

  7. Real-time image-processing algorithm for markerless tumour tracking using X-ray fluoroscopic imaging

    PubMed Central

    2014-01-01

    Objective: To ensure accuracy in respiratory-gating treatment, X-ray fluoroscopic imaging is used to detect tumour position in real time. Detection accuracy is strongly dependent on image quality, particularly positional differences between the patient and treatment couch. We developed a new algorithm to improve the quality of images obtained in X-ray fluoroscopic imaging and report the preliminary results. Methods: Two oblique X-ray fluoroscopic images were acquired using a dynamic flat panel detector (DFPD) for two patients with lung cancer. The weighting factor was applied to the DFPD image in respective columns, because most anatomical structures, as well as the treatment couch and port cover edge, were aligned in the superior–inferior direction when the patient lay on the treatment couch. The weighting factors for the respective columns were varied until the standard deviation of the pixel values within the image region was minimized. Once the weighting factors were calculated, the quality of the DFPD image was improved by applying the factors to multiframe images. Results: Applying the image-processing algorithm produced substantial improvement in the quality of images, and the image contrast was increased. The treatment couch and irradiation port edge, which were not related to a patient's position, were removed. The average image-processing time was 1.1 ms, showing that this fast image processing can be applied to real-time tumour-tracking systems. Conclusion: These findings indicate that this image-processing algorithm improves the image quality in patients with lung cancer and successfully removes objects not related to the patient. Advances in knowledge: Our image-processing algorithm might be useful in improving gated-treatment accuracy. PMID:24661056

  8. Quantification of fluoroscopic imaging system contrast by using video waveform monitoring.

    PubMed

    Taubel, J P; Schueler, B A; Vrieze, T J; Gray, J E

    2001-01-01

    A noninvasive method was developed for quantifying the overall contrast of fluoroscopic imaging systems within the clinical setting by using a simple phantom and common video test equipment. In this method, an acrylic phantom with four holes filled with varying amounts of air and aluminum is placed on the entrance exposure side of a patient-equivalent acrylic phantom. The air- and aluminum-filled holes provide a stepped gray-scale pattern that is displayed on the examination room viewing monitor when the phantom is fluoroscopically imaged under automatic brightness control. A video waveform monitor or oscilloscope is then used to quantify those video signal voltage levels as a contrast index value, which is defined as the maximum range of the video signal voltage levels of the gray-scale steps. The method is repeatable and allows quantification of the contrast of the imaging system. It can also be used to optimize video parameters, provide comparative data for quality control monitoring, and characterize overall contrast differences between systems. Experience with this method suggests that there is excellent correlation between the clinical perception of image contrast and the contrast index, with contrast index changes of approximately 15% being seen clinically.

  9. Real-time respiratory phase matching between 2D fluoroscopic images and 3D CT images for precise percutaneous lung biopsy.

    PubMed

    Weon, Chijun; Kim, Mina; Park, Chang Min; Ra, Jong Beom

    2017-08-20

    A 3D CT image is used along with real-time 2D fluoroscopic images in the state-of-the-art cone-beam CT system to guide percutaneous lung biopsy (PLB). To improve the guiding accuracy by compensating for respiratory motion, we propose an algorithm for real-time matching of 2D fluoroscopic images to multiple 3D CT images of different respiratory phases that is robust to the small movement and deformation due to cardiac motion. Based on the transformations obtained from non-rigid registration between two 3D CT images acquired at expiratory and inspiratory phases, we first generate sequential 3D CT images (or a 4D CT image) and the corresponding 2D digitally reconstructed radiographs (DRRs) of vessels. We then determine 3D CT images corresponding to each real-time 2D fluoroscopic image, by matching the 2D fluoroscopic image to a 2D DRR. Quantitative evaluations performed with 20 clinical datasets show that registration errors of anatomical features between a 2D fluoroscopic image and its matched 2D DRR are less than 3mm on average. Registration errors of a target lesion are determined to be roughly 3mm on average for 10 datasets. We propose a real-time matching algorithm to compensate for respiratory motion between a 2D fluoroscopic image and 3D CT images of the lung, regardless of cardiac motion, based on a newly improved matching measure. The proposed algorithm can improve the accuracy of a guiding system for the PLB by providing 3D images precisely registered to 2D fluoroscopic images in real-time, without time-consuming respiratory gated or cardiac gated CT images. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  10. Contrast changes in fluoroscopic imaging systems and statistical variations of these changes

    NASA Technical Reports Server (NTRS)

    Bailey, N. A.

    1973-01-01

    Experimental studies have indicated that: (1) The response of digitized fluoroscopic imaging systems is linear systems is linear with contrast over a rather wide range of absorber and cavity thicknesses. (2) Contrast changes associated with the addition of aluminum, iodine containing contrast agents and air of thicknesses 1mm or less can be detected with a 95% confidence level. (3) The standard deviation associated with such determination using clinically available X-ray generators and video disc recording is less than 1 percent. A large flat screen X-ray image intensifier has been constructed and some preliminary results obtained. Sensitivity achieved makes dose reduction a factor often greater than previously reported for a system using a conventional X-ray image intensifier.

  11. A novel fluoroscopic-assisted balloon thrombectomy technique for thrombosed hemodialysis prosthetic grafts [corrected].

    PubMed

    Kakkos, Stavros K; Haddad, Joseph A; Haddad, Georges K

    2010-01-01

    Previous studies have shown that stenosis of the arterial anastomosis of thrombosed hemodialysis (HD) grafts, unmasked after conventional thrombectomy, very often necessitate subsequent arterial angioplasty. The aim of this study was to describe a novel fluoroscopic-assisted balloon thrombectomy technique which permits simultaneous arterial angioplasty (should this is required) for thrombosed HD grafts. Thirty patients with 36 thrombotic episodes of their prosthetic HD grafts participated in this study. A balloon angioplasty catheter is placed beyond the arterial anastomosis, over a guidewire; the balloon is inflated with contrast solution under fluoroscopy and pulled back to remove the arterial thrombus from the anastomosis. Any coexisting stenosis revealed by balloon indentation is completely dilated at that time, rather than after the thrombectomy. Mechanical thrombolysis of the graft and venous outflow is then performed with the AngioJet catheter (Possis Medical, Inc). Technical and clinical success rates (the latter defined as one subsequent HD session) of the procedure were 100% and 94%, respectively. No complications, including arterial embolism, vessel rupture or pulmonary embolism, were encountered. Primary assisted patency at 3 and 6 months was 51% and 32%, respectively, while functional secondary patency at the same follow-up points was 78%. Our technique is safe and also effective in both short- and long-term follow-up. Because it offers convenience, since the treatment of arterial anastomotic stenoses is accomplished in one (rather than two) steps, this method deserves further investigation.

  12. Threshold contrast detail detectability measurement of the fluoroscopic image quality of a dynamic solid-state digital x-ray image detector.

    PubMed

    Davies, A G; Cowen, A R; Kengyelics, S M; Bury, R F; Bruijns, T J

    2001-01-01

    Solid-state digital x-ray imaging detectors of flat-panel construction will play an increasingly important role in future medical imaging facilities. Solid-state detectors that will support both dynamic (including fluoroscopic) and radiographic image recording are under active development. The image quality of an experimental solid-state digital x-ray image detector operating in a continuous fluoroscopy mode has been investigated. The threshold contrast detail detectability (TCDD) technique was used to compare the fluoroscopic imaging performance of an experimental dynamic solid-state digital x-ray image detector with that of a reference image intensifier television (IITV) fluoroscopy system. The reference system incorporated Plumbicon TV. Results were presented as a threshold detection index, or H(T)(A), curves. Measurements were made over a range of mean entrance air kerma (EAK) rates typically used in conventional IITV fluoroscopy. At the upper and mid EAK rate range (440 and 220 nGy/s) the solid-state detector outperformed the reference IITV fluoroscopy system as measured by TCDD performance. At the lowest measured EAK rate (104 nGy/s), the solid-state detector produces slightly inferior TCDD performance compared with the reference system. Although not statistically significant at this EAK rate, the difference will increase as EAK is lowered further. Overall the TCDD results and early clinical experiences support the proposition that a current design of dynamic solid-state detector produces image quality competitive with that of modern IITV fluoroscopy systems. These findings encourage the development of compact and versatile universal x-ray imaging systems based upon solid-state detector technology to support R & F and vascular/interventional applications.

  13. Two-tuohy needle and catheter technique for fluoroscopically guided percutaneous drainage of spinal epidural abscess: a case report.

    PubMed

    Perez-Toro, Marco R; Burton, Allen W; Hamid, Basem; Koyyalagunta, Dhanalakshmi

    2009-04-01

    The incidence of spinal epidural abscess has increased in the past decades. Traditionally, management was based on surgical decompression. More recent studies have shown conservative management has successful outcomes in selected patients. We present a case, in which an elderly woman presented with new onset radicular pain and mild leukocytosis more than a week after a complicated revision of an intrathecal catheter in place for management of chronic axial low back pain. Magentic resonance imaging (MRI) revealed a posterior epidural abscess from T12 to L2. Two Touhy needles were placed in the epidural space with fluoroscopic guidance for drainage of the abscess. A catheter was then advanced into the epidural space for irrigation with saline and an antibiotic solution. Intravenous antibiotics were continued for a total of 6 weeks. Radicular pain resolved immediately post-procedure. Serial MRIs also showed decreasing size of the abscess. Posterior spinal epidural abscesses may be successfully treated by way of the two Touhy needle and catheter technique for drainage and irrigation. This procedure should be reserved for patients that present with no neurological deficits or deemed nonsurgical candidates. Patients should continue on prolonged intravenous antibiotics and be monitored closely for clinical deterioration and undergo serial follow-up MRIs.

  14. Evaluation of methods to produce an image library for automatic patient model localization for dose mapping during fluoroscopically guided procedures

    NASA Astrophysics Data System (ADS)

    Kilian-Meneghin, Josh; Xiong, Z.; Rudin, S.; Oines, A.; Bednarek, D. R.

    2017-03-01

    The purpose of this work is to evaluate methods for producing a library of 2D-radiographic images to be correlated to clinical images obtained during a fluoroscopically-guided procedure for automated patient-model localization. The localization algorithm will be used to improve the accuracy of the skin-dose map superimposed on the 3D patient- model of the real-time Dose-Tracking-System (DTS). For the library, 2D images were generated from CT datasets of the SK-150 anthropomorphic phantom using two methods: Schmid's 3D-visualization tool and Plastimatch's digitally-reconstructed-radiograph (DRR) code. Those images, as well as a standard 2D-radiographic image, were correlated to a 2D-fluoroscopic image of a phantom, which represented the clinical-fluoroscopic image, using the Corr2 function in Matlab. The Corr2 function takes two images and outputs the relative correlation between them, which is fed into the localization algorithm. Higher correlation means better alignment of the 3D patient-model with the patient image. In this instance, it was determined that the localization algorithm will succeed when Corr2 returns a correlation of at least 50%. The 3D-visualization tool images returned 55-80% correlation relative to the fluoroscopic-image, which was comparable to the correlation for the radiograph. The DRR images returned 61-90% correlation, again comparable to the radiograph. Both methods prove to be sufficient for the localization algorithm and can be produced quickly; however, the DRR method produces more accurate grey-levels. Using the DRR code, a library at varying angles can be produced for the localization algorithm.

  15. Three-dimensional kinematic estimation of mobile-bearing total knee arthroplasty from x-ray fluoroscopic images

    NASA Astrophysics Data System (ADS)

    Yamazaki, Takaharu; Futai, Kazuma; Tomita, Tetsuya; Sato, Yoshinobu; Yoshikawa, Hideki; Tamura, Shinichi; Sugamoto, Kazuomi

    2011-03-01

    To achieve 3D kinematic analysis of total knee arthroplasty (TKA), 2D/3D registration techniques, which use X-ray fluoroscopic images and computer-aided design (CAD) model of the knee implant, have attracted attention in recent years. These techniques could provide information regarding the movement of radiopaque femoral and tibial components but could not provide information of radiolucent polyethylene insert, because the insert silhouette on X-ray image did not appear clearly. Therefore, it was difficult to obtain 3D kinemaitcs of polyethylene insert, particularly mobile-bearing insert that move on the tibial component. This study presents a technique and the accuracy for 3D kinematic analysis of mobile-bearing insert in TKA using X-ray fluoroscopy, and finally performs clinical applications. For a 3D pose estimation technique of the mobile-bearing insert in TKA using X-ray fluoroscopy, tantalum beads and CAD model with its beads are utilized, and the 3D pose of the insert model is estimated using a feature-based 2D/3D registration technique. In order to validate the accuracy of the present technique, experiments including computer simulation test were performed. The results showed the pose estimation accuracy was sufficient for analyzing mobile-bearing TKA kinematics (the RMS error: about 1.0 mm, 1.0 degree). In the clinical applications, seven patients with mobile-bearing TKA in deep knee bending motion were studied and analyzed. Consequently, present technique enables us to better understand mobile-bearing TKA kinematics, and this type of evaluation was thought to be helpful for improving implant design and optimizing TKA surgical techniques.

  16. SU-C-209-02: 3D Fluoroscopic Image Generation From Patient-Specific 4DCBCT-Based Motion Models Derived From Clinical Patient Images

    SciTech Connect

    Dhou, S; Cai, W; Hurwitz, M; Williams, C; Lewis, J

    2016-06-15

    Purpose: We develop a method to generate time varying volumetric images (3D fluoroscopic images) using patient-specific motion models derived from four-dimensional cone-beam CT (4DCBCT). Methods: Motion models are derived by selecting one 4DCBCT phase as a reference image, and registering the remaining images to it. Principal component analysis (PCA) is performed on the resultant displacement vector fields (DVFs) to create a reduced set of PCA eigenvectors that capture the majority of respiratory motion. 3D fluoroscopic images are generated by optimizing the weights of the PCA eigenvectors iteratively through comparison of measured cone-beam projections and simulated projections generated from the motion model. This method was applied to images from five lung-cancer patients. The spatial accuracy of this method is evaluated by comparing landmark positions in the 3D fluoroscopic images to manually defined ground truth positions in the patient cone-beam projections. Results: 4DCBCT motion models were shown to accurately generate 3D fluoroscopic images when the patient cone-beam projections contained clearly visible structures moving with respiration (e.g., the diaphragm). When no moving anatomical structure was clearly visible in the projections, the 3D fluoroscopic images generated did not capture breathing deformations, and reverted to the reference image. For the subset of 3D fluoroscopic images generated from projections with visibly moving anatomy, the average tumor localization error and the 95th percentile were 1.6 mm and 3.1 mm respectively. Conclusion: This study showed that 4DCBCT-based 3D fluoroscopic images can accurately capture respiratory deformations in a patient dataset, so long as the cone-beam projections used contain visible structures that move with respiration. For clinical implementation of 3D fluoroscopic imaging for treatment verification, an imaging field of view (FOV) that contains visible structures moving with respiration should be

  17. Comparison of a fluoroscopic 3-dimensional imaging system and conventional CT in detection of pars fractures in the cadaveric lumbar spine.

    PubMed

    Kepler, Christopher K; Pavlov, Helene; Herzog, Richard J; Rawlins, Bernard A; Endo, Yoshimi; Green, Daniel W

    2012-12-01

    Cadaveric Study. To compare a fluoroscopic imaging system with computed tomography (CT) and radiographs in detection of spondylolysis and radiation exposure in a cadaver model. Lumbar spondylolysis is defined as a defect or fracture of the pars interarticularis and occurs with or without anterior spondylolisthesis. CT scan is the gold standard imaging study for spondylolysis but is limited by the supine position, which may cause reduction of anterolisthesis and by ionizing radiation, which limits the frequency of follow-up scans. Thirteen intact cadaveric lumbar spine segments with 26 pars were randomized to be left intact or to undergo simulated fracture using a 1.3 mm oscillating microsurgical saw. Fifteen pars underwent simulated fracture and 11 pars were left intact. Lumbar spine segments were imaged using plain radiographs, multiplanar fluoroscopic imaging, and conventional CT scan. The images were interpreted by 3 observers blinded to the number and location of defects. Radiation exposure and doses were recorded from all imaging units. Average radiation doses were 0.0025 mSv for each radiograph, 0.23 mSv (low dose) and 0.47 mSv (high dose) for fluoroscopic imaging, and 1.5 mSv for conventional CT imaging (pediatric dose setting). Evaluation of radiographs for spondylolysis had sensitivity of 98% and specificity of 97%. Evaluation using low-dose fluoroscopic images, high-dose fluoroscopic images, and CT scan images correctly identified the status of all pars based on multiplanar images; sensitivity and specificity were 100%. Kappa analysis demonstrated a value of 0.89 for radiographic interpretation indicating excellent agreement. Kappa values describing agreement for image interpretation for fluoroscopic imaging and CT scan were equal to 1.0, representing perfect agreement. Three-dimensional fluoroscopic imaging provides comparable diagnostic imaging with CT scan in an experimental cadaveric model of spondylolysis using up to 85% less radiation than

  18. Optimization of multi-image pose recovery of fluoroscope tracking (FTRAC) fiducial in an image-guided femoroplasty system

    NASA Astrophysics Data System (ADS)

    Liu, Wen P.; Armand, Mehran; Otake, Yoshito; Taylor, Russell H.

    2011-03-01

    Percutaneous femoroplasty [1], or femoral bone augmentation, is a prospective alternative treatment for reducing the risk of fracture in patients with severe osteoporosis. We are developing a surgical robotics system that will assist orthopaedic surgeons in planning and performing a patient-specific, augmentation of the femur with bone cement. This collaborative project, sponsored by the National Institutes of Health (NIH), has been the topic of previous publications [2],[3] from our group. This paper presents modifications to the pose recovery of a fluoroscope tracking (FTRAC) fiducial during our process of 2D/3D registration of X-ray intraoperative images to preoperative CT data. We show improved automata of the initial pose estimation as well as lower projection errors with the advent of a multiimage pose optimization step.

  19. SU-E-J-126: Generation of Fluoroscopic 3D Images Using Single X-Ray Projections on Realistic Modified XCAT Phantom Data.

    PubMed

    Mishra, P; Li, R; St James, S; Yue, Y; Mak, R; Berbeco, R; Lewis, J

    2012-06-01

    To simulate the process of generating fluoroscopic 3D treatment images from 4DCT and measured 2D x-ray projections using a realistic modified XCAT phantom based on measured patient 3D tumor trajectories. First, the existing XCAT phantom is adapted to incorporate measured patient lung tumor trajectories. Realistic diaphragm and chest wall motion are automatically generated based on input tumor motion and position, producing synchronized, realistic motion in the phantom. Based on 4DCT generated with the XCAT phantom, we derive patient-specific motion models that are used to generate 3D fluoroscopic images. Patient-specific models are created in two steps: first, the displacement vector fields (DVFs) are obtained through deformable image registration of each phase of 4DCT with respect to a reference image (typically peak-exhale). Each phase is registered to the reference image to obtain (n-1) DVFs. Second, the most salient characteristics in the DVFs are captured in a compact representation through principal component analysis (PCA). Since PCA is a linear decomposition method, all the DVFs can be represented as linear combinations of eigenvectors. Fluoroscopic 3D images are obtained using the projection image to determine optimal weights for the eigenvectors. These weights are determined through iterative optimization of a cost function relating the projection image to the 3D image via the PCA lung motion model and a projection operator. Constructing fluoroscopic 3D images is thus reduced to finding optimal weights for the eigenvectors. Fluoroscopic 3D treatment images were generated using the modified XCAT phantom. The average relative error of the reconstructed image over 30 sec is 0.0457 HU and the standard deviation is 0.0063. The XCAT phantom was modified to produce realistic images by incorporating patient tumor trajectories. The modified XCAT phantom can be used to simulate the process of generating fluoroscopic 3D treatment images from 4DCT and 2D x

  20. Investigation on effect of image lag in fluoroscopic images obtained with a dynamic flat-panel detector (FPD) on accuracy of target tracking in radiotherapy.

    PubMed

    Tanaka, Rie; Ichikawa, Katsuhiro; Mori, Shinichiro; Dobashi, Suguru; Kumagai, Motoki; Kawashima, Hiroki; Minohara, Shinichi; Sanada, Sigeru

    2010-01-01

    Real-time tumor tracking in external radiotherapy can be achieved by diagnostic (kV) X-ray imaging with a dynamic flat-panel detector (FPD). The purpose of this study was to address image lag in target tracking and its influence on the accuracy of tumor tracking. Fluoroscopic images were obtained using a direct type of dynamic FPD. Image lag properties were measured without test devices according to IEC 62220-1. Modulation transfer function (MTF) and profile curves were measured on the edges of a moving tungsten plate at movement rate of 10 and 20 mm/s, covering lung tumor movement of normal breathing. A lung tumor and metal sphere with blurred edge due to image lag was simulated using the results and then superimposed on breathing chest radiographs of a patient. The moving target with and without image lag was traced using a template-matching technique. In the results, the image lag for the first frame after X-ray cutoff was 2.0% and decreased to less than 0.1% in the fifth frame. In the measurement of profile curves on the edges of static and moving tungsten material plates, the effect of image lag was seen as blurred edges of the plate. The blurred edges of a moving target were indicated as reduction of MTF. However, the target could be traced within an error of ± 5 mm. The results indicated that there was no effect of image lag on target tracking in usual breathing speed in a radiotherapy situation.

  1. Nonrigid 2D registration of fluoroscopic coronary artery image sequence with propagated deformation field

    NASA Astrophysics Data System (ADS)

    Park, Taewoo; Shin, Seung Yeon; Hong, Youngtaek; Lee, Soochahn; Chang, Hyuk-Jae; Yun, Il Dong

    2017-03-01

    We propose a novel method for nonrigid registration of coronary arteries within frames of a fluoroscopic X-ray angiogram sequence with propagated deformation field. The aim is to remove the motion of coronary arteries in order to simplify further registration of the 3D vessel structure obtained from computed tomography angiography, with the x-ray sequence. The Proposed methodology comprises two stages: propagated adjacent pairwise nonrigid registration, and, sequence-wise fixed frame nonrigid registration. In the first stage, a propagated nonrigid transformation reduces the disparity search range for each frame sequentially. In the second stage, nonrigid registration is applied for all frames with a fixed target frame, thus generating a motion-aligned sequence. Experimental evaluation conducted on a set of 7 fluoroscopic angiograms resulted in reduced target registration error, compared to previous methods, showing the effectiveness of the proposed methodology.

  2. Investigation of first ray mobility during gait by kinematic fluoroscopic imaging-a novel method

    PubMed Central

    2012-01-01

    Background It is often suggested that sagittal instability at the first tarso-metatarsal joint level is a primary factor for hallux valgus and that sagittal instability increases with the progression of the deformity. The assessment of the degree of vertical instability is usually made by clinical evaluation while any measurements mostly refer to a static assessment of medial ray mobility (i.e. the plantar/dorsal flexion in the sagittal plane). Testing methods currently available cannot attribute the degree of mobility to the corresponding anatomical joints making up the medial column of the foot. The aim of this study was to develop a technique which allows for a quantification of the in-vivo sagittal mobility of the joints of the medial foot column during the roll-over process under full weight bearing. Methods Mobility of first ray bones was investigated by dynamic distortion-free fluoroscopy (25 frames/s) of 14 healthy volunteers and 8 patients with manifested clinical instability of the first ray. A CAD-based evaluation method allowed the determination of mobility and relative displacements and rotations of the first ray bones within the sagittal plane during the stance phase of gait. Results Total flexion of the first ray was found to be 13.63 (SD 6.14) mm with the healthy volunteers and 13.06 (SD 8.01) mm with the patients (resolution: 0.245 mm/pixel). The dorsiflexion angle was 5.27 (SD 2.34) degrees in the healthy volunteers and increased to 5.56 (SD 3.37) degrees in the patients. Maximum rotations were found at the naviculo-cuneiform joints and least at the first tarso-metatarsal joint level in both groups. Conclusions Dynamic fluoroscopic assessment has been shown to be a valuable tool for characterisation of the kinematics of the joints of the medial foot column during gait. A significant difference in first ray flexion and angular rotation between the patients and healthy volunteers however could not be found. PMID:22316084

  3. Percutaneous Cervical Vertebroplasty in a MultifunctionalImage-Guided Therapy Suite: Hybrid Lateral Approach to C1 andC4 Under CT and Fluoroscopic Guidance

    SciTech Connect

    Huegli, R.W. Schaeren, S.; Jacob, A.L.; Martin, J.B.; Wetzel, S.G.

    2005-06-15

    A 76-year-old patient suffering from two painful osteolytic metastases in C1 and C4 underwent percutaneous vertebroplasty by a hybrid technique in a multi-functional image-guided therapy suite (MIGTS). Two trocars were first placed into the respective bodies of C1 and C4 under fluoroscopic computed tomography guidance using a lateral approach. Thereafter, the patient was transferred on a moving table to the digital subtraction angiography unit in the same room for implant injection. Good pain relief was achieved by this minimally invasive procedure without complications. A hybrid approach for vertebroplasty in a MIGTS appears to be safe and feasible and might be indicated in selected cases for difficult accessible lesions.

  4. SU-E-J-01: 3D Fluoroscopic Image Estimation From Patient-Specific 4DCBCT-Based Motion Models

    SciTech Connect

    Dhou, S; Hurwitz, M; Lewis, J; Mishra, P

    2014-06-01

    Purpose: 3D motion modeling derived from 4DCT images, taken days or weeks before treatment, cannot reliably represent patient anatomy on the day of treatment. We develop a method to generate motion models based on 4DCBCT acquired at the time of treatment, and apply the model to estimate 3D time-varying images (referred to as 3D fluoroscopic images). Methods: Motion models are derived through deformable registration between each 4DCBCT phase, and principal component analysis (PCA) on the resulting displacement vector fields. 3D fluoroscopic images are estimated based on cone-beam projections simulating kV treatment imaging. PCA coefficients are optimized iteratively through comparison of these cone-beam projections and projections estimated based on the motion model. Digital phantoms reproducing ten patient motion trajectories, and a physical phantom with regular and irregular motion derived from measured patient trajectories, are used to evaluate the method in terms of tumor localization, and the global voxel intensity difference compared to ground truth. Results: Experiments included: 1) assuming no anatomic or positioning changes between 4DCT and treatment time; and 2) simulating positioning and tumor baseline shifts at the time of treatment compared to 4DCT acquisition. 4DCBCT were reconstructed from the anatomy as seen at treatment time. In case 1) the tumor localization error and the intensity differences in ten patient were smaller using 4DCT-based motion model, possible due to superior image quality. In case 2) the tumor localization error and intensity differences were 2.85 and 0.15 respectively, using 4DCT-based motion models, and 1.17 and 0.10 using 4DCBCT-based models. 4DCBCT performed better due to its ability to reproduce daily anatomical changes. Conclusion: The study showed an advantage of 4DCBCT-based motion models in the context of 3D fluoroscopic images estimation. Positioning and tumor baseline shift uncertainties were mitigated by the 4DCBCT

  5. Solid-state fluoroscopic imager for high-resolution angiography: Physical characteristics of an 8 cm×8 cm experimental prototype

    PubMed Central

    Vedantham, Srinivasan; Karellas, Andrew; Suryanarayanan, Sankararaman; Onishi, Steven K.

    2008-01-01

    In this paper, the performance of an 8 cm×8 cm three-side buttable charge-coupled device (CCD)-based imager specially designed for high-resolution fluoroscopy and operating in fluoroscopic (30 frames/second) mode is presented in terms of the presampling modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE). The 8 cm×8 cm CCD imager is coupled to a 450 μm thick CsI:Tl scintillator by nondemagnifying (straight, 1:1) fiberoptics. The CCD imager has a fundamental pixel pitch of 39 μm and incorporates an optically opaque interline (data) channel. The CCD imager was operated at 156 μm pixel pitch by binning 4×4 adjacent pixels prior to readout. The fluoroscopic image lag was measured and accounted for in the DQE estimate to provide lag-corrected DQE. The measured limiting spatial resolution at 10% presampling MTF with the imager operated at 156 μm pixel pitch (Nyquist sampling limit: 3.21 cy/mm) was 3.6 cy/mm. In the pulsed fluoroscopic mode, the first-frame image lag was less than 0.9%. The lag-corrected DQE(0) of ~0.62 was achieved even at a low fluoroscopic exposure rate of 1 μR/frame. Grid phantom measurements indicate no appreciable distortion. Results from DQE and image lag measurements at fluoroscopic exposure rates combined with the high spatial resolution observed from the MTF suggest that this type of imager or its variants may be a potential candidate for high-resolution neuro-interventional imaging, cardiovascular imaging, pediatric angiography, and small animal imaging. Since the CCD is three-side buttable, four such CCD modules can be joined to form a 2×2 matrix providing a field of view of 16 cm×16 cm. PMID:15259649

  6. A study of the x-ray image quality improvement in the examination of the respiratory system based on the new image processing technique

    NASA Astrophysics Data System (ADS)

    Nagai, Yuichi; Kitagawa, Mayumi; Torii, Jun; Iwase, Takumi; Aso, Tomohiko; Ihara, Kanyu; Fujikawa, Mari; Takeuchi, Yumiko; Suzuki, Katsumi; Ishiguro, Takashi; Hara, Akio

    2014-03-01

    Recently, the double contrast technique in a gastrointestinal examination and the transbronchial lung biopsy in an examination for the respiratory system [1-3] have made a remarkable progress. Especially in the transbronchial lung biopsy, better quality of x-ray fluoroscopic images is requested because this examination is performed under a guidance of x-ray fluoroscopic images. On the other hand, various image processing methods [4] for x-ray fluoroscopic images have been developed as an x-ray system with a flat panel detector [5-7] is widely used. A recursive filtering is an effective method to reduce a random noise in x-ray fluoroscopic images. However it has a limitation for its effectiveness of a noise reduction in case of a moving object exists in x-ray fluoroscopic images because the recursive filtering is a noise reduction method by adding last few images. After recursive filtering a residual signal was produced if a moving object existed in x-ray images, and this residual signal disturbed a smooth procedure of the examinations. To improve this situation, new noise reduction method has been developed. The Adaptive Noise Reduction [ANR] is the brand-new noise reduction technique which can be reduced only a noise regardless of the moving object in x-ray fluoroscopic images. Therefore the ANR is a very suitable noise reduction method for the transbronchial lung biopsy under a guidance of x-ray fluoroscopic images because the residual signal caused of the moving object in x-ray fluoroscopic images is never produced after the ANR. In this paper, we will explain an advantage of the ANR by comparing of a performance between the ANR images and the conventional recursive filtering images.

  7. SU-E-I-37: Low-Dose Real-Time Region-Of-Interest X-Ray Fluoroscopic Imaging with a GPU-Accelerated Spatially Different Bilateral Filtering

    SciTech Connect

    Chung, H; Lee, J; Pua, R; Cho, S; Jung, W

    2014-06-01

    Purpose: The purpose of our study is to reduce imaging radiation dose while maintaining image quality of region of interest (ROI) in X-ray fluoroscopy. A low-dose real-time ROI fluoroscopic imaging technique which includes graphics-processing-unit- (GPU-) accelerated image processing for brightness compensation and noise filtering was developed in this study. Methods: In our ROI fluoroscopic imaging, a copper filter is placed in front of the X-ray tube. The filter contains a round aperture to reduce radiation dose to outside of the aperture. To equalize the brightness difference between inner and outer ROI regions, brightness compensation was performed by use of a simple weighting method that applies selectively to the inner ROI, the outer ROI, and the boundary zone. A bilateral filtering was applied to the images to reduce relatively high noise in the outer ROI images. To speed up the calculation of our technique for real-time application, the GPU-acceleration was applied to the image processing algorithm. We performed a dosimetric measurement using an ion-chamber dosimeter to evaluate the amount of radiation dose reduction. The reduction of calculation time compared to a CPU-only computation was also measured, and the assessment of image quality in terms of image noise and spatial resolution was conducted. Results: More than 80% of dose was reduced by use of the ROI filter. The reduction rate depended on the thickness of the filter and the size of ROI aperture. The image noise outside the ROI was remarkably reduced by the bilateral filtering technique. The computation time for processing each frame image was reduced from 3.43 seconds with single CPU to 9.85 milliseconds with GPU-acceleration. Conclusion: The proposed technique for X-ray fluoroscopy can substantially reduce imaging radiation dose to the patient while maintaining image quality particularly in the ROI region in real-time.

  8. Fluoroscopic-guided radiofrequency ablation of the basivertebral nerve: application and analysis with multiple imaging modalities in an ovine model (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Bergeron, Jeffrey A.; Eskey, Cliff J.; Attawia, Mohammed; Patel, Samit J.; Ryan, Thomas P.; Pellegrino, Richard; Sutton, Jeffrey; Crombie, John; Paul, B. T.; Hoopes, P. J.

    2005-04-01

    Pathologic involvement of the basivertebral nerve, an intraosseous vertebral nerve found in humans and most mammalian species, may play a role in some forms of back pain. This study was designed to assess the feasibility and effects of the percutaneous delivery of radiofrequency (RF) energy to thermally ablate the basivertebral nerve in the lumbar vertebrae of mature sheep. Using fluoroscopic guidance, a RF bipolar device was placed and a thermal dose delivered to lumbar vertebral bodies in sheep. Post-treatment assessment included multiple magnetic resonance imaging (MRI) techniques and computed tomography (CT). These data were analyzed and correlated to histopathology and morphometry findings to describe the cellular and boney structural changes resulting from the treatment. Imaging modalities MRI and CT can be implemented to non-invasively describe treatment region and volume, marrow cellular effects, and bone density alterations immediately following RF treatment and during convalescence. Such imaging can be utilized to assess treatment effects and refine the thermal dose to vertebral body volume ratio used in treatment planning. This information will be used to improve the therapeutic ratio and develop a treatment protocol for human applications.

  9. Training Distal Locking Screw Insertion Skills to Novice Trainees: A Comparison Between Fluoroscopic- and Electromagnetic-Guided Techniques.

    PubMed

    Leroux, Timothy; Khoshbin, Amir; Nousiainen, Markku T

    2015-10-01

    To compare the effect fluoroscopy or electromagnetic (EM) guidance has on the learning of locking screw insertion in tibial nails in surgical novices. A randomized, prospective, controlled trial was conducted involving 18 surgical trainees with no prior experience inserting locking screws in intramedullary nails. After a training session using fluoroscopy, participants underwent a pretest using fluoroscopic guidance. Participants were then randomized into either the fluoroscopy or EM group and were further trained using their respective technique. Post, retention, and transfer tests were conducted. Outcomes included task completion, drill attempts, screw changes, and radiation time. Intragroup comparisons revealed that the EM group used significantly less drill attempts during the post and retention tests compared with the pretest (P = 0.016 and P = 0.016, respectively). Intergroup comparisons revealed that the EM group was (1) more likely to complete the task during the retention test (P = 0.043) and (2) had significantly less radiation time during the post and retention tests (P = 0.002 and P = 0.003, respectively). Radiation time in the EM group during the transfer test increased to a level equal to what the fluoroscopy group used during the post and retention tests (P = 0.71 and P = 0.92, respectively). No other significant between-group differences occurred. EM guidance may be safely used to assist in the training of surgical novices in the skill of distal locking screw insertion. Not only does this technology significantly improve the ability to complete the task and decrease radiation use but also it does so without compromising skill acquisition. Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

  10. In vivo kinematic study of the tarsal joints complex based on fluoroscopic 3D-2D registration technique.

    PubMed

    Chen Wang, M D; Geng, Xiang; Wang, Shaobai; Xin Ma, M D; Xu Wang, M D; Jiazhang Huang, M D; Chao Zhang, M D; Li Chen, M S; Yang, Junsheng; Wang, Kan

    2016-09-01

    The tarsal bones articulate with each other and demonstrate complicated kinematic characteristics. The in vivo motions of these tarsal joints during normal gait are still unclear. Seven healthy subjects were recruited and fourteen feet in total were tested in the current study. Three dimensional models of the tarsal bones were first created using CT scanning. Corresponding local 3D coordinate systems of each tarsal bone was subsequently established for 6DOF motion decompositions. The fluoroscopy system captured the lateral fluoroscopic images of the targeted tarsal region whilst the subject was walking. Seven key pose images during the stance phase were selected and 3D to 2D bone model registrations were performed on each image to determine joint positions. The 6DOF motions of each tarsal joint during gait were then obtained by connecting these positions together. The TNJ (talo-navicular joint) exhibited the largest ROMs (range of motion) on all rotational directions with 7.39±2.75°of dorsi/plantarflexion, 21.12±4.68°of inversion/eversion, and 16.11±4.44°of internal/external rotation. From heel strike to midstance, the TNJ, STJ (subtalar joint), and CCJ (calcaneao-cuboid joint) were associated with 5.97°, 5.04°, and 3.93°of dorsiflexion; 15.46°, 8.21°, and 5.82°of eversion; and 9.75°, 7.6°, and 4.99°of external rotation, respectively. Likewise, from midstance to heel off, the TNJ, STJ, and CCJ were associated with 6.39, 6.19°, and 4.47°of plantarflexion; 18.57°, 11.86°, and 6.32°of inversion and 13.95°, 9.66°, and 7.58°of internal rotation, respectively. In conclusion, among the tarsal joints, the TNJ exhibited the greatest rotational mobility. Synchronous and homodromous rotational motions were detected for TNJ, STJ, and CCJ during the stance phase.

  11. Percutaneous drainage of psoas and iliopsoas muscle abscesses with a one-step technique under real-time computed tomography fluoroscopic guidance.

    PubMed

    Kinoshita, Mitsuhiro; Takao, Shoichiro; Takechi, Katsuya; Takeda, Yoshitsugu; Miyamoto, Kanako; Yamanaka, Moriaki; Akagawa, Yoko; Iwamoto, Seiji; Osaki, Kyosuke; Tani, Hayato; Ohnishi, Norio; Shirono, Ryozo

    2016-01-01

    To evaluate the utility and safety of drainage catheter installation for psoas/iliopsoas muscle abscesses using a one-step technique under the guidance of real-time computed tomography (CT) fluoroscopy. Ten psoas or iliopsoas muscle abscesses in 7 patients that were treated with percutaneous drainage were included in this study. All drainage procedures were carried out using a one-step technique under real-time CT fluoroscopic guidance. The drainage catheter insertion was performed successfully with the one-step technique in all lesions. Improvements in the patients' symptoms and blood test results were seen after the drainage procedure in all cases. In addition, postoperative CT scans demonstrated that the abscesses had reduced in size or disappeared in all but one patient, who was transferred to another institution while the drainage catheter was still in place. No major complications were seen in any case. The one-step procedure is simple to perform. The percutaneous drainage of psoas or iliopsoas muscle abscesses with the one-step technique under real-time CT fluoroscopic guidance is accurate and safe. Moreover, compared with the two-step technique the one-step procedure results in a shorter drainage procedure and exposes the patient and operator to lower amounts of radiation. J. Med. Invest. 63: 323-327, August, 2016.

  12. 21 CFR 1020.32 - Fluoroscopic equipment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... fluoroscopic image receptor using photographic film or a video camera when the x-ray source is operated in a...-hold feature that are not recorded. (C) When a mode of operation has an optional high-level control...

  13. SU-E-I-42: Normalized Embryo/fetus Doses for Fluoroscopically Guided Pacemaker Implantation Procedures Calculated Using a Monte Carlo Technique

    SciTech Connect

    Damilakis, J; Stratakis, J; Solomou, G

    2014-06-01

    Purpose: It is well known that pacemaker implantation is sometimes needed in pregnant patients with symptomatic bradycardia. To our knowledge, there is no reported experience regarding radiation doses to the unborn child resulting from fluoroscopy during pacemaker implantation. The purpose of the current study was to develop a method for estimating embryo/fetus dose from fluoroscopically guided pacemaker implantation procedures performed on pregnant patients during all trimesters of gestation. Methods: The Monte Carlo N-Particle (MCNP) radiation transport code was employed in this study. Three mathematical anthropomorphic phantoms representing the average pregnant patient at the first, second and third trimesters of gestation were generated using Bodybuilder software (White Rock science, White Rock, NM). The normalized embryo/fetus dose from the posteroanterior (PA), the 30° left-anterior oblique (LAO) and the 30° right-anterior oblique (RAO) projections were calculated for a wide range of kVp (50–120 kVp) and total filtration values (2.5–9.0 mm Al). Results: The results consist of radiation doses normalized to a) entrance skin dose (ESD) and b) dose area product (DAP) so that the dose to the unborn child from any fluoroscopic technique and x-ray device used can be calculated. ESD normalized doses ranged from 0.008 (PA, first trimester) to 2.519 μGy/mGy (RAO, third trimester). DAP normalized doses ranged from 0.051 (PA, first trimester) to 12.852 μGy/Gycm2 (RAO, third trimester). Conclusion: Embryo/fetus doses from fluoroscopically guided pacemaker implantation procedures performed on pregnant patients during all stages of gestation can be estimated using the method developed in this study. This study was supported by the Greek Ministry of Education and Religious Affairs, General Secretariat for Research and Technology, Operational Program ‘Education and Lifelong Learning’, ARISTIA (Research project: CONCERT)

  14. Feasibility of low-dose digital pulsed video-fluoroscopic swallow exams (VFSE): effects on radiation dose and image quality.

    PubMed

    Weiss, Jakob; Notohamiprodjo, Mike; Neumaier, Klement; Li, Minglun; Flatz, Wilhelm; Nikolaou, Konstantin; Pomschar, Andreas

    2017-09-01

    Background Fluoroscopy is a frequently used examination in clinical routine without appropriate research evaluation latest hardware and software equipment. Purpose To evaluate the feasibility of low-dose pulsed video-fluoroscopic swallowing exams (pVFSE) to reduce dose exposure in patients with swallowing disorders compared to high-resolution radiograph examinations (hrVFSE) serving as standard of reference. Material and Methods A phantom study (Alderson-Rando Phantom, 60 thermoluminescent dosimeters [TLD]) was performed for dose measurements. Acquisition parameters were as follows: (i) pVFSE: 76.7 kV, 57 mA, 0.9 Cu mm, pulse rate/s 30; (ii) hrVFSE: 68.0 kV, 362 mA, 0.2 Cu mm, pictures 30/s. The dose area product (DAP) indicated by the detector system and the radiation dose derived from the TLD measurements were analyzed. In a patient study, image quality was assessed qualitatively (5-point Likert scale, 5 = hrVFSE; two independent readers) and quantitatively (SNR) in 35 patients who subsequently underwent contrast-enhanced pVFSE and hrVFSE. Results Phantom measurements showed a dose reduction per picture of factor 25 for pVFSE versus hrVFSE images (0.0025 mGy versus 0.062 mGy). The DAP (µGym(2)) was 28.0 versus 810.5 (pVFSE versus hrVFSE) for an average examination time of 30 s. Direct and scattered organ doses were significantly lower for pVFSE as compared to hrVFSE ( P < 0.05). Image quality was rated 3.9 ± 0.5 for pVFSE versus the hrVFSE standard; depiction of the contrast agent 4.8 ± 0.3; noise 3.6 ± 0.5 ( P < 0.05); SNR calculations revealed a relative decreased of 43.9% for pVFSE as compared to hrVFSE. Conclusion Pulsed VFSE is feasible, providing diagnostic image quality at a significant dose reduction as compared to hrVFSE.

  15. Fluoroscopic x-ray imaging with amorphous silicon thin-film arrays

    NASA Astrophysics Data System (ADS)

    Schiebel, Ulrich W.; Conrads, Norbert; Jung, Norbert; Weibrecht, Martin; Wieczorek, Herfried K.; Zaengel, Thomas T.; Powell, M. J.; French, I. D.; Glasse, C.

    1994-05-01

    The dream of an all-solid state large area x-ray image sensor with digital readout and full dynamic performance will most probably find a first realization in 2D thin-film amorphous silicon arrays. In this paper we address in particular the evaluation of the limits of the signal/noise ratio in this concept. Using small prototype detectors measurements of MTF and noise power spectra have been made as a function of x-ray dose. The results are given in terms of the detective quantum efficiency as a function of dose and spatial frequency. We further present an analysis of the different noise sources and their dependence on the detector parameters, and we provide estimates on the maximum signals that may be achieved per unit dose. The intrinsic lag of the amorphous silicon photodiodes causes a second problem area with this type of x-ray detectors. Especially in radiography/fluoroscopy mixed applications, memory effects may not be negligible.

  16. Imaging technologies and techniques.

    PubMed

    Rafter, Patrick; Phillips, Patrick; Vannan, Mani A

    2004-05-01

    Equipment manufacturers provide contrast-specific detection techniques that have excellent sensitivity and excellent agent-to-tissue specificity along with helpful tools that improve workflow efficiency dramatically. Excellent contrast agents have been approved for LV opacification and are available worldwide. Techniques designed for low-MI imaging offer real-time acquisition capabilities and lead to faster examinations. Techniques designed for medium-MI imaging offer better sensitivity than low-MI techniques while maintaining the benefit of rapid image acquisition. Techniques designed for high-MI imaging offer the best sensitivity with longer acquisition times. These techniques are viable means for imaging contrast agents tailored to clinical needs. Progress by contrast agent manufacturers, equipment manufacturers, and physicians will continue to drive improvements in the areas of detection and clinical workflow for improved patient care.

  17. Intra-operative fiducial-based CT/fluoroscope image registration framework for image-guided robot-assisted joint fracture surgery.

    PubMed

    Dagnino, Giulio; Georgilas, Ioannis; Morad, Samir; Gibbons, Peter; Tarassoli, Payam; Atkins, Roger; Dogramadzi, Sanja

    2017-08-01

    Joint fractures must be accurately reduced minimising soft tissue damages to avoid negative surgical outcomes. To this regard, we have developed the RAFS surgical system, which allows the percutaneous reduction of intra-articular fractures and provides intra-operative real-time 3D image guidance to the surgeon. Earlier experiments showed the effectiveness of the RAFS system on phantoms, but also key issues which precluded its use in a clinical application. This work proposes a redesign of the RAFS's navigation system overcoming the earlier version's issues, aiming to move the RAFS system into a surgical environment. The navigation system is improved through an image registration framework allowing the intra-operative registration between pre-operative CT images and intra-operative fluoroscopic images of a fractured bone using a custom-made fiducial marker. The objective of the registration is to estimate the relative pose between a bone fragment and an orthopaedic manipulation pin inserted into it intra-operatively. The actual pose of the bone fragment can be updated in real time using an optical tracker, enabling the image guidance. Experiments on phantom and cadavers demonstrated the accuracy and reliability of the registration framework, showing a reduction accuracy (sTRE) of about [Formula: see text] (phantom) and [Formula: see text] (cadavers). Four distal femur fractures were successfully reduced in cadaveric specimens using the improved navigation system and the RAFS system following the new clinical workflow (reduction error [Formula: see text], [Formula: see text]. Experiments showed the feasibility of the image registration framework. It was successfully integrated into the navigation system, allowing the use of the RAFS system in a realistic surgical application.

  18. NOTE: A feasibility study of markerless fluoroscopic gating for lung cancer radiotherapy using 4DCT templates

    NASA Astrophysics Data System (ADS)

    Li, Ruijiang; Lewis, John H.; Cerviño, Laura I.; Jiang, Steve B.

    2009-10-01

    A major difficulty in conformal lung cancer radiotherapy is respiratory organ motion, which may cause clinically significant targeting errors. Respiratory-gated radiotherapy allows for more precise delivery of prescribed radiation dose to the tumor, while minimizing normal tissue complications. Gating based on external surrogates is limited by its lack of accuracy, while gating based on implanted fiducial markers is limited primarily by the risk of pneumothorax due to marker implantation. Techniques for fluoroscopic gating without implanted fiducial markers (markerless gating) have been developed. These techniques usually require a training fluoroscopic image dataset with marked tumor positions in the images, which limits their clinical implementation. To remove this requirement, this study presents a markerless fluoroscopic gating algorithm based on 4DCT templates. To generate gating signals, we explored the application of three similarity measures or scores between fluoroscopic images and the reference 4DCT template: un-normalized cross-correlation (CC), normalized cross-correlation (NCC) and normalized mutual information (NMI), as well as average intensity (AI) of the region of interest (ROI) in the fluoroscopic images. Performance was evaluated using fluoroscopic and 4DCT data from three lung cancer patients. On average, gating based on CC achieves the highest treatment accuracy given the same efficiency, with a high target coverage (average between 91.9% and 98.6%) for a wide range of nominal duty cycles (20-50%). AI works well for two patients out of three, but failed for the third patient due to interference from the heart. Gating based on NCC and NMI usually failed below 50% nominal duty cycle. Based on this preliminary study with three patients, we found that the proposed CC-based gating algorithm can generate accurate and robust gating signals when using 4DCT reference template. However, this observation is based on results obtained from a very limited

  19. Management of pediatric radiation dose using GE fluoroscopic equipment.

    PubMed

    Belanger, Barry; Boudry, John

    2006-09-01

    In this article, we present GE Healthcare's design philosophy and implementation of X-ray imaging systems with dose management for pediatric patients, as embodied in its current radiography and fluoroscopy and interventional cardiovascular X-ray product offerings. First, we present a basic framework of image quality and dose in the context of a cost-benefit trade-off, with the development of the concept of imaging dose efficiency. A set of key metrics of image quality and dose efficiency is presented, including X-ray source efficiency, detector quantum efficiency (DQE), detector dynamic range, and temporal response, with an explanation of the clinical relevance of each. Second, we present design methods for automatically selecting optimal X-ray technique parameters (kVp, mA, pulse width, and spectral filtration) in real time for various clinical applications. These methods are based on an optimization scheme where patient skin dose is minimized for a target desired image contrast-to-noise ratio. Operator display of skin dose and Dose-Area Product (DAP) is covered, as well. Third, system controls and predefined protocols available to the operator are explained in the context of dose management and the need to meet varying clinical procedure imaging demands. For example, fluoroscopic dose rate is adjustable over a range of 20:1 to adapt to different procedure requirements. Fourth, we discuss the impact of image processing techniques upon dose minimization. In particular, two such techniques, dynamic range compression through adaptive multiband spectral filtering and fluoroscopic noise reduction, are explored in some detail. Fifth, we review a list of system dose-reduction features, including automatic spectral filtration, virtual collimation, variable-rate pulsed fluoroscopic, grid and no-grid techniques, and fluoroscopic loop replay with store. In addition, we describe a new feature that automatically minimizes the patient-to-detector distance, along with an

  20. Percutaneous antegrade scaphoid screw placement: a feasibility and accuracy analysis of a novel electromagnetic navigation technique versus a standard fluoroscopic method.

    PubMed

    Hoffmann, M; Reinsch, O D; Petersen, J P; Schröder, M; Priemel, M; Spiro, A S; Rueger, J M; Yarar, S

    2015-03-01

    Central screw positioning in the scaphoid provides biomechanical advantages. A prospective randomized study of six fluoroscopically guided and six electromagnetically navigated screw (ENS) placements was performed on human cadavers. Accuracy of screw position was determined. Intraoperative fluoroscopy exposure times, readjustments of drilling directions, complete restarts and complications were documented. The ENS method provided a mean time benefit of 7.34 min compared with the standard method and the mean screw length ratio (SLR coronar: ENS 0.96 ± 0.04 mm, SFF: 0.92 ± 0.04 mm, P = 0.065; SLR sagittal: ENS 0.98 ± 0.02 mm, SFF: 0.91 ± 0.04 mm, P = 0.009) and the screw axis deviation angle (AD coronar: ENS 3.33 ± 2.34°, SFF: 10.33 ± 2.58°, P = 0.002; AD sagittal: ENS 2.83 ± 0.98°, SFF: 11.00 ± 6.16°, P = 0.002) were lower. Using the electromagnetic navigation procedure no drilling readjustments or restarts were required, no cortical breach occurred. Compared with the standard fluoroscopic technique, the ENS method used in this study showed higher accuracy, less complications, required less operation and radiation exposure time. Copyright © 2014 John Wiley & Sons, Ltd.

  1. Multimodality imaging techniques.

    PubMed

    Martí-Bonmatí, Luis; Sopena, Ramón; Bartumeus, Paula; Sopena, Pablo

    2010-01-01

    In multimodality imaging, the need to combine morphofunctional information can be approached by either acquiring images at different times (asynchronous), and fused them through digital image manipulation techniques or simultaneously acquiring images (synchronous) and merging them automatically. The asynchronous post-processing solution presents various constraints, mainly conditioned by the different positioning of the patient in the two scans acquired at different times in separated machines. The best solution to achieve consistency in time and space is obtained by the synchronous image acquisition. There are many multimodal technologies in molecular imaging. In this review we will focus on those multimodality image techniques more commonly used in the field of diagnostic imaging (SPECT-CT, PET-CT) and new developments (as PET-MR). The technological innovations and development of new tracers and smart probes are the main key points that will condition multimodality image and diagnostic imaging professionals' future. Although SPECT-CT and PET-CT are standard in most clinical scenarios, MR imaging has some advantages, providing excellent soft-tissue contrast and multidimensional functional, structural and morphological information. The next frontier is to develop efficient detectors and electronics systems capable of detecting two modality signals at the same time. Not only PET-MR but also MR-US or optic-PET will be introduced in clinical scenarios. Even more, MR diffusion-weighted, pharmacokinetic imaging, spectroscopy or functional BOLD imaging will merge with PET tracers to further increase molecular imaging as a relevant medical discipline. Multimodality imaging techniques will play a leading role in relevant clinical applications. The development of new diagnostic imaging research areas, mainly in the field of oncology, cardiology and neuropsychiatry, will impact the way medicine is performed today. Both clinical and experimental multimodality studies, in

  2. Video x-ray progressive scanning: new technique for decreasing x-ray exposure without decreasing image quality during cardiac catheterization

    SciTech Connect

    Holmes, D.R. Jr.; Bove, A.A.; Wondrow, M.A.; Gray, J.E.

    1986-05-01

    A newly developed video x-ray progressive scanning system improves image quality, decreases radiation exposure, and can be added to any pulsed fluoroscopic x-ray system using a video display without major system modifications. With use of progressive video scanning, the radiation entrance exposure rate measured with a vascular phantom was decreased by 32 to 53% in comparison with a conventional fluoroscopic x-ray system. In addition to this substantial decrease in radiation exposure, the quality of the image was improved because of less motion blur and artifact. Progressive video scanning has the potential for widespread application to all pulsed fluoroscopic x-ray systems. Use of this technique should make cardiac catheterization procedures and all other fluoroscopic procedures safer for the patient and the involved medical and paramedical staff.

  3. Image compression technique

    DOEpatents

    Fu, C.Y.; Petrich, L.I.

    1997-03-25

    An image is compressed by identifying edge pixels of the image; creating a filled edge array of pixels each of the pixels in the filled edge array which corresponds to an edge pixel having a value equal to the value of a pixel of the image array selected in response to the edge pixel, and each of the pixels in the filled edge array which does not correspond to an edge pixel having a value which is a weighted average of the values of surrounding pixels in the filled edge array which do correspond to edge pixels; and subtracting the filled edge array from the image array to create a difference array. The edge file and the difference array are then separately compressed and transmitted or stored. The original image is later reconstructed by creating a preliminary array in response to the received edge file, and adding the preliminary array to the received difference array. Filling is accomplished by solving Laplace`s equation using a multi-grid technique. Contour and difference file coding techniques also are described. The techniques can be used in a method for processing a plurality of images by selecting a respective compression approach for each image, compressing each of the images according to the compression approach selected, and transmitting each of the images as compressed, in correspondence with an indication of the approach selected for the image. 16 figs.

  4. Image compression technique

    DOEpatents

    Fu, Chi-Yung; Petrich, Loren I.

    1997-01-01

    An image is compressed by identifying edge pixels of the image; creating a filled edge array of pixels each of the pixels in the filled edge array which corresponds to an edge pixel having a value equal to the value of a pixel of the image array selected in response to the edge pixel, and each of the pixels in the filled edge array which does not correspond to an edge pixel having a value which is a weighted average of the values of surrounding pixels in the filled edge array which do correspond to edge pixels; and subtracting the filled edge array from the image array to create a difference array. The edge file and the difference array are then separately compressed and transmitted or stored. The original image is later reconstructed by creating a preliminary array in response to the received edge file, and adding the preliminary array to the received difference array. Filling is accomplished by solving Laplace's equation using a multi-grid technique. Contour and difference file coding techniques also are described. The techniques can be used in a method for processing a plurality of images by selecting a respective compression approach for each image, compressing each of the images according to the compression approach selected, and transmitting each of the images as compressed, in correspondence with an indication of the approach selected for the image.

  5. WE-G-207-06: 3D Fluoroscopic Image Generation From Patient-Specific 4DCBCT-Based Motion Models Derived From Physical Phantom and Clinical Patient Images

    SciTech Connect

    Dhou, S; Cai, W; Hurwitz, M; Rottmann, J; Myronakis, M; Cifter, F; Berbeco, R; Lewis, J; Williams, C; Mishra, P; Ionascu, D

    2015-06-15

    Purpose: Respiratory-correlated cone-beam CT (4DCBCT) images acquired immediately prior to treatment have the potential to represent patient motion patterns and anatomy during treatment, including both intra- and inter-fractional changes. We develop a method to generate patient-specific motion models based on 4DCBCT images acquired with existing clinical equipment and used to generate time varying volumetric images (3D fluoroscopic images) representing motion during treatment delivery. Methods: Motion models are derived by deformably registering each 4DCBCT phase to a reference phase, and performing principal component analysis (PCA) on the resulting displacement vector fields. 3D fluoroscopic images are estimated by optimizing the resulting PCA coefficients iteratively through comparison of the cone-beam projections simulating kV treatment imaging and digitally reconstructed radiographs generated from the motion model. Patient and physical phantom datasets are used to evaluate the method in terms of tumor localization error compared to manually defined ground truth positions. Results: 4DCBCT-based motion models were derived and used to generate 3D fluoroscopic images at treatment time. For the patient datasets, the average tumor localization error and the 95th percentile were 1.57 and 3.13 respectively in subsets of four patient datasets. For the physical phantom datasets, the average tumor localization error and the 95th percentile were 1.14 and 2.78 respectively in two datasets. 4DCBCT motion models are shown to perform well in the context of generating 3D fluoroscopic images due to their ability to reproduce anatomical changes at treatment time. Conclusion: This study showed the feasibility of deriving 4DCBCT-based motion models and using them to generate 3D fluoroscopic images at treatment time in real clinical settings. 4DCBCT-based motion models were found to account for the 3D non-rigid motion of the patient anatomy during treatment and have the potential

  6. Renal imaging techniques.

    PubMed

    Hierholzer, K; Hierholzer, J

    1997-01-01

    The ancient approach to obtain an image of the kidneys (and other internal organs) was 'section-inspection-imaging' by drawing, painting, sculpturing, and modelling. The present study follows chronologically the development and use of sectioning techniques from ancient (often forbidden) methods to modern microdissection and maceration of silicone-rubber-injected tubules. Inspection evolved from the use of the naked eye to magnifying lenses, microscopes and finally electron microscopy. Pertinent examples such as the description of the kidneys as the site of urine formation, the visualization of loop structures in the renal medulla and the imaging of tight junction strands are discussed. Inspection or visualization of renal structure and function has been revolutionized by modern noninvasive techniques, such as X-ray imaging, imaging by radioisotopes, ultrasound, computer tomography and nuclear magnetic resonance. Pertinent examples are given demonstrating the potency of the various techniques. The contribution of computerized data evaluation is discussed. The development of micropuncture and microperfusion techniques has opened the field for direct imaging not only of renal (sub)structural details but also of functional parameters such as transtubular reabsorption rates, single glomerular capillary filtration and conductance of the paracellular pathway. We focus particularly on techniques specifically designed to visualize renal hemodynamic and transport parameters.

  7. A study on quality improvement of x-ray imaging of the respiratory-system based on a new image processing technique

    NASA Astrophysics Data System (ADS)

    Torii, Jun; Nagai, Yuichi; Horita, Tatsuya; Matsumoto, Yuuji; Izumo, Takehiro; Kitagawa, Mayumi; Ihara, Kanyu; Nakamura, Tadashi; Mukoyoshi, Wataru; Tennmei, Kounosuke; Suzuki, Katsumi; Hara, Akio; Sasada, Shinji; Aso, Tomohiko

    2015-03-01

    Recently, the double contrast technique in a gastrointestinal examination and the transbronchial lung biopsy in an examination for the respiratory system [1-3] have made a remarkable progress. Especially in the transbronchial lung biopsy, better quality of x-ray fluoroscopic images is requested because this examination is performed under a guidance of x-ray fluoroscopic images. On the other hand, various image processing methods [4] for x-ray fluoroscopic images have been developed as an x-ray system with a flat panel detector [5-7] is widely used. New noise reduction processing, Adaptive Noise Reduction [ANR], was announced in SPIE last year.[8] ANR is a new image processing technique which is capable of extracting and reducing noise components regardless of moving objects in fluoroscopy images. However, for further enhancement of noise reduction effect in clinical use, it was used in combination with a recursive filter, which is a time axis direction filter. Due to this, the recursive filter generated image lags when there are moving objects in the fluoroscopic images, and these image lags sometimes became hindrance in performing smooth bronchoscopy. This is because recursive filters reduce noise by adding multiple fluoroscopy images. Therefore, we have developed new image processing technique, Motion Tracking Noise Reduction [MTNR] for decreasing image lags as well as noise. This ground-breaking image processing technique detects global motion in images with high accuracy, determines the pixels to track the motion, and applies a motion tracking-type time filter. With this, image lags are removed remarkably while realizing the effective noise reduction. In this report, we will explain the effect of MTNR by comparing the performance of MTNR images [MTNR] and ANR + Recursive filter-applied images [ANR + Recursive filter].

  8. Automated quantification of lumbar vertebral kinematics from dynamic fluoroscopic sequences

    NASA Astrophysics Data System (ADS)

    Camp, Jon; Zhao, Kristin; Morel, Etienne; White, Dan; Magnuson, Dixon; Gay, Ralph; An, Kai-Nan; Robb, Richard

    2009-02-01

    We hypothesize that the vertebra-to-vertebra patterns of spinal flexion and extension motion of persons with lower back pain will differ from those of persons who are pain-free. Thus, it is our goal to measure the motion of individual lumbar vertebrae noninvasively from dynamic fluoroscopic sequences. Two-dimensional normalized mutual information-based image registration was used to track frame-to-frame motion. Software was developed that required the operator to identify each vertebra on the first frame of the sequence using a four-point "caliper" placed at the posterior and anterior edges of the inferior and superior end plates of the target vertebrae. The program then resolved the individual motions of each vertebra independently throughout the entire sequence. To validate the technique, 6 cadaveric lumbar spine specimens were potted in polymethylmethacrylate and instrumented with optoelectric sensors. The specimens were then placed in a custom dynamic spine simulator and moved through flexion-extension cycles while kinematic data and fluoroscopic sequences were simultaneously acquired. We found strong correlation between the absolute flexionextension range of motion of each vertebra as recorded by the optoelectric system and as determined from the fluoroscopic sequence via registration. We conclude that this method is a viable way of noninvasively assessing twodimensional vertebral motion.

  9. Scalp imaging techniques

    NASA Astrophysics Data System (ADS)

    Otberg, Nina; Shapiro, Jerry; Lui, Harvey; Wu, Wen-Yu; Alzolibani, Abdullateef; Kang, Hoon; Richter, Heike; Lademann, Jürgen

    2017-05-01

    Scalp imaging techniques are necessary tools for the trichological practice and for visualization of permeation, penetration and absorption processes into and through the scalp and for the research on drug delivery and toxicology. The present letter reviews different scalp imaging techniques and discusses their utility. Moreover, two different studies on scalp imaging techniques are presented in this letter: (1) scalp imaging with phototrichograms in combination with laser scanning microscopy, and (2) follicular measurements with cyanoacrylate surface replicas and light microscopy in combination with laser scanning microscopy. The experiments compare different methods for the determination of hair density on the scalp and different follicular measures. An average terminal hair density of 132 hairs cm-2 was found in 6 Caucasian volunteers and 135 hairs cm-2 in 6 Asian volunteers. The area of the follicular orifices accounts to 16.3% of the skin surface on average measured with laser scanning microscopy images. The potential volume of the follicular infundibulum was calculated based on the laser scanning measurements and is found to be 4.63 mm3 per cm2 skin on average. The experiments show that hair follicles are quantitatively relevant pathways and potential reservoirs for topically applied drugs and cosmetics.

  10. Accuracy of Percutaneous Lumbosacral Pedicle Screw Placement Using the Oblique Fluoroscopic View Based on Computed Tomography Evaluations

    PubMed Central

    Sato, Koji; Kanemura, Tokumi; Iwase, Toshiki; Togawa, Daisuke; Matsuyama, Yukihiro

    2016-01-01

    Study Design Retrospective. Purpose This study aims to investigate the accuracy of the oblique fluoroscopic view, based on preoperative computed tomography (CT) images for accurate placement of lumbosacral percutaneous pedicle screws (PPS). Overview of Literature Although PPS misplacement has been reported as one of the main complications in minimally invasive spine surgery, there is no comparative data on the misplacement rate among different fluoroscopic techniques, or comparing such techniques with open procedures. Methods We retrospectively selected 230 consecutive patients who underwent posterior spinal fusion with a pedicle screw construct for degenerative lumbar disease, and divided them into 3 groups, those who had undergone: minimally invasive percutaneous procedure using biplane (lateral and anterior-posterior views using a single C-arm) fluoroscope views (group M-1), minimally invasive percutaneous procedure using the oblique fluoroscopic view based on preoperative CT (group M-2), and conventional open procedure using a lateral fluoroscopic view (group O: controls). The relative position of the screw to the pedicle was graded for the pedicle breach as no breach, <2 mm, 2–4 mm, or >4 mm. Inaccuracy was calculated and assessed according to the spinal level, direction and neurological deficit. Inter-group radiation exposure was estimated using fluoroscopy time. Results Inaccuracy involved an incline toward L5, causing medial or lateral perforation of pedicles in group M-1, but it was distributed relatively equally throughout multiple levels in groups M-2 and controls. The mean fluoroscopy time/case ranged from 1.6 to 3.9 minutes. Conclusions Minimally invasive lumbosacral PPS placement using the conventional fluoroscopic technique carries an increased risk of inaccurate screw placement and resultant neurological deficits, compared with that of the open procedure. Inaccuracy tended to be distributed between medial and lateral perforations of the L5 pedicle

  11. PILOT STUDY TO ASSESS MEAL PROGRESSION THROUGH THE GASTROINTESTINAL TRACT OF HABITUATED DOGS DETERMINED BY FLUOROSCOPIC IMAGING WITHOUT SEDATION OR PHYSICAL RESTRAINT.

    PubMed

    Wrigglesworth, David J; Bailey, Michael Q; Colyer, Alison; Hughes, Kevin R

    2016-11-01

    A limiting factor of radiographic contrast studies is the requirement for restraint of the animal in order to reduce movement artifacts. To demonstrate that gastrointestinal transit can be analyzed by a barium meal in nonsedated and unrestrained dogs, a pilot study of six adult Labrador retriever dogs was undertaken. Study subjects were selected by convenience sampling from an available population of Labrador dogs and were trained to stand motionless during radiographic fluoroscopy. Following a meal containing 7% w/w powdered barium sulfate, radiographic images were generated using a digital fluoroscope C-arm, at intervals of 5, 15, and 30 min, and at 1, 2, 3, 4, 5, 6, 7, and 8 h. A qualitative assessment of fill density using a 5-point scale was made for the stomach, small intestine, and ascending, transverse, and descending regions of the colon at each timepoint. Gastric emptying half-time occurred between 1 and 2 h postmeal. Mean fill density of the small intestine increased from 15 min postmeal and reached a peak at 3 h postmeal. Mean fill density of the proximal large intestine mirrored that of the small intestine. The distal large intestine remained empty for the first 2 h postmeal, then increased between hours 2 and 5 postmeal, and was subsequently at maximum fill density from hour 6 postmeal onwards. Fluoroscopic observation of a barium contrast meal provided an effective indication of the amount and progression of ingested food through the various regions of the gastrointestinal tract in habituated, fully conscious dogs. © 2016 American College of Veterinary Radiology.

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

    NASA Astrophysics Data System (ADS)

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

    1999-05-01

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

  13. [Progress in imaging techniques].

    PubMed

    Mishima, Kazuaki; Otsuka, Tsukasa

    2013-05-01

    Today it is common to perform real-time diagnosis and treatment via live broadcast as a method of education and to spread new technology for diagnosis and therapy in medical fields. Live medical broadcasts have developed along with broadcast technology. In the early days, live video feeds were sent from operating rooms to classrooms and lecture halls in universities and hospitals. However, the development of imaging techniques and communication networks enabled live broadcasts that bi-directionally link operating rooms and meeting halls during scientific meetings and live demonstration courses. Live broadcasts therefore became an important method for education and the dissemination of new medical technologies. The development of imaging techniques has contributed to more realistic live broadcasts through such innovative techniques as three-dimensional viewing and higher-definition 4K technology. In the future, live broadcasts will be transmitted on personal computers using regular Internet connections. In addition to the enhancement of image delivery technology, it will also be necessary to examine the entire image delivery environment carefully, including issues of security and privacy of personal information.

  14. Brain Vascular Imaging Techniques

    PubMed Central

    Laviña, Bàrbara

    2016-01-01

    Recent major improvements in a number of imaging techniques now allow for the study of the brain in ways that could not be considered previously. Researchers today have well-developed tools to specifically examine the dynamic nature of the blood vessels in the brain during development and adulthood; as well as to observe the vascular responses in disease situations in vivo. This review offers a concise summary and brief historical reference of different imaging techniques and how these tools can be applied to study the brain vasculature and the blood-brain barrier integrity in both healthy and disease states. Moreover, it offers an overview on available transgenic animal models to study vascular biology and a description of useful online brain atlases. PMID:28042833

  15. Radiation injuries after fluoroscopic procedures.

    PubMed

    Mettler, Fred A; Koenig, Titus R; Wagner, Louis K; Kelsey, Charles A

    2002-10-01

    Fluoroscopically guided diagnostic and interventional procedures have become much more commonplace over the last decade. Current fluoroscopes are easily capable of producing dose rates in the range of 0.2 Gy (20 rads) per minute. The dose rate often changes dramatically with patient positioning and size. Most machines currently in use have no method to display approximate patient dose other than the rough surrogate of total fluoroscopy time. This does not include patient dose incurred during fluorography (serial imaging or cine runs), which can be considerably greater than dose during fluoroscopy. There have been over 100 cases of documented radiation skin and underlying tissue injury, a large portion of which resulted in dermal necrosis. The true number of injuries is undoubtedly much higher. The highest dose procedures are complex interventions such as those involving percutaneous angioplasties, stent placements, embolizations, and TIPS. In some cases skin doses have been in excess of 60 Gy (6000 rads). In many instances the procedures have been performed by physicians with little training in radiation effects, little appreciation of the radiation injuries that are possible or the strategies that could have been used to reduce both patient and staff doses. Almost all of the severe injuries that have occurred were avoidable.

  16. Fluoroscopic evaluation of skeletal problems

    SciTech Connect

    Choplin, R.H.; Gilula, L.A.; Murphy, W.A.

    1981-12-01

    Fluoroscopically positioned spot films are widely used in gastrointestinal and chest roentgenography. Little or no mention is made of the diagnostic use of fluoroscopic spot filming for skeletal roentgenography in major texts or recent literature, and a rough survey of practicing radiologists showed us that such procedure was frequently underutilized or not utilized. While skeletal pathology is usually depicted quite accurately by plain radiographs there are times when a problem may be rapidly and simply clarified by fluoroscopically positioned spot films. In an attempt to assess the value of fluoroscopy for evaluation of musculoskeletal problems, we reviewed 46 cases in which fluoroscopically positioned spot films were obtained.

  17. Image processing techniques for acoustic images

    NASA Astrophysics Data System (ADS)

    Murphy, Brian P.

    1991-06-01

    The primary goal of this research is to test the effectiveness of various image processing techniques applied to acoustic images generated in MATLAB. The simulated acoustic images have the same characteristics as those generated by a computer model of a high resolution imaging sonar. Edge detection and segmentation are the two image processing techniques discussed in this study. The two methods tested are a modified version of the Kalman filtering and median filtering.

  18. Nondestructive Acoustic Imaging Techniques

    NASA Astrophysics Data System (ADS)

    Schmitz, Volker

    Acoustic imaging techniques are used in the field of nondestructive testing of technical components to measure defects such as lack of side wall fusion or cracks in welded joints. Data acquisition is performed by a remote-controlled manipulator and a PC for the mass storage of the high-frequency time-of-flight data at each probe position. The quality of the acoustic images and the interpretation relies on the proper understanding of the transmitted wave fronts and the arrangement of the probes in pulse-echo mode or in pitch-and-catch arrangement. The use of the Synthetic Aperture Focusing Technique allows the depth-dependent resolution to be replaced by a depth-independent resolution and the signal-to-noise ratio to be improved. Examples with surface-connected cracks are shown to demonstrate the improved features. The localization accuracy could be improved by entering 2-dimensional or 3-dimensional reconstructed data into the environment of a 3-dimensional CAD drawing. The propagation of ultrasonic waves through austenitic welds is disturbed by the anisotropic and inhomogeneous structure of the material. The effect is more or less severe depending upon the longitudinal or shear wave modes. To optimize the performance of an inspection software tool, a 3-dimensional CAD-Ray program has been implemented, where the shape of the inhomogeneous part of a weld can be simulated together with the grain structure based on the elastic constants. Ray-tracing results are depicted for embedded and for surface-connected defects.

  19. A CMOS-based high resolution fluoroscope (HRF) detector prototype with 49.5 μm pixels for use in endovascular image guided interventions (EIGI).

    PubMed

    Russ, M; Shankar, A; Setlur Nagesh, S V; Ionita, C N; Bednarek, D R; Rudin, S

    2017-02-11

    X-ray detectors to meet the high-resolution requirements for endovascular image-guided interventions (EIGIs) are being developed and evaluated. A new 49.5-micron pixel prototype detector is being investigated and compared to the current suite of high-resolution fluoroscopic (HRF) detectors. This detector featuring a 300-micron thick CsI(Tl) scintillator, and low electronic noise CMOS readout is designated the HRF-CMOS50. To compare the abilities of this detector with other existing high resolution detectors, a standard performance metric analysis was applied, including the determination of the modulation transfer function (MTF), noise power spectra (NPS), noise equivalent quanta (NEQ), and detective quantum efficiency (DQE) for a range of energies and exposure levels. The advantage of the smaller pixel size and reduced blurring due to the thin phosphor was exemplified when the MTF of the HRF-CMOS50 was compared to the other high resolution detectors, which utilize larger pixels, other optical designs or thicker scintillators. However, the thinner scintillator has the disadvantage of a lower quantum detective efficiency (QDE) for higher diagnostic x-ray energies. The performance of the detector as part of an imaging chain was examined by employing the generalized metrics GMTF, GNEQ, and GDQE, taking standard focal spot size and clinical imaging parameters into consideration. As expected, the disparaging effects of focal spot unsharpness, exacerbated by increasing magnification, degraded the higher-frequency performance of the HRF-CMOS50, while increasing scatter fraction diminished low-frequency performance. Nevertheless, the HRF-CMOS50 brings improved resolution capabilities for EIGIs, but would require increased sensitivity and dynamic range for future clinical application.

  20. A CMOS-based high-resolution fluoroscope (HRF) detector prototype with 49.5μm pixels for use in endovascular image guided interventions (EIGI)

    NASA Astrophysics Data System (ADS)

    Russ, M.; Shankar, A.; Setlur Nagesh, S. V.; Ionita, C. N.; Bednarek, D. R.; Rudin, S.

    2017-03-01

    X-ray detectors to meet the high-resolution requirements for endovascular image-guided interventions (EIGIs) are being developed and evaluated. A new 49.5-micron pixel prototype detector is being investigated and compared to the current suite of high-resolution fluoroscopic (HRF) detectors. This detector featuring a 300-micron thick CsI(Tl) scintillator, and low electronic noise CMOS readout is designated the HRF- CMOS50. To compare the abilities of this detector with other existing high resolution detectors, a standard performance metric analysis was applied, including the determination of the modulation transfer function (MTF), noise power spectra (NPS), noise equivalent quanta (NEQ), and detective quantum efficiency (DQE) for a range of energies and exposure levels. The advantage of the smaller pixel size and reduced blurring due to the thin phosphor was exemplified when the MTF of the HRF-CMOS50 was compared to the other high resolution detectors, which utilize larger pixels, other optical designs or thicker scintillators. However, the thinner scintillator has the disadvantage of a lower quantum detective efficiency (QDE) for higher diagnostic x-ray energies. The performance of the detector as part of an imaging chain was examined by employing the generalized metrics GMTF, GNEQ, and GDQE, taking standard focal spot size and clinical imaging parameters into consideration. As expected, the disparaging effects of focal spot unsharpness, exacerbated by increasing magnification, degraded the higher-frequency performance of the HRF-CMOS50, while increasing scatter fraction diminished low-frequency performance. Nevertheless, the HRF-CMOS50 brings improved resolution capabilities for EIGIs, but would require increased sensitivity and dynamic range for future clinical application.

  1. A theoretical and experimental evaluation of the microangiographic fluoroscope: A high-resolution region-of-interest x-ray imager

    SciTech Connect

    Jain, Amit; Bednarek, D. R.; Ionita, Ciprian; Rudin, S.

    2011-07-15

    Purpose: The increasing need for better image quality and high spatial resolution for successful endovascular image-guided interventions (EIGIs) and the inherent limitations of the state-of-the-art detectors provide motivation to develop a detector system tailored to the specific, demanding requirements of neurointerventional applications.Method: A microangiographic fluoroscope (MAF) was developed to serve as a high-resolution, region-of-interest (ROI) x-ray imaging detector in conjunction with large lower-resolution full field-of-view (FOV) state-of-the-art x-ray detectors. The newly developed MAF is an indirect x-ray imaging detector capable of providing real-time images (30 frames per second) with high-resolution, high sensitivity, no lag and low instrumentation noise. It consists of a CCD camera coupled to a Gen 2 dual-stage microchannel plate light image intensifier (LII) through a fiber-optic taper. A 300 {mu}m thick CsI(Tl) phosphor serving as the front end is coupled to the LII. The LII is the key component of the MAF and the large variable gain provided by it enables the MAF to operate as a quantum-noise-limited detector for both fluoroscopy and angiography. Results: The linear cascade model was used to predict the theoretical performance of the MAF, and the theoretical prediction showed close agreement with experimental findings. Linear system metrics such as MTF and DQE were used to gauge the detector performance up to 10 cycles/mm. The measured zero frequency DQE(0) was 0.55 for an RQA5 spectrum. A total of 21 stages were identified for the whole imaging chain and each stage was characterized individually. Conclusions: The linear cascade model analysis provides insight into the imaging chain and may be useful for further development of the MAF detector. The preclinical testing of the prototype detector in animal procedures is showing encouraging results and points to the potential for significant impact on EIGIs when used in conjunction with a state

  2. Fluoroscopic dose reduction using a digital television nose-reduction device

    SciTech Connect

    Albow, R.C.; Jaffe, C.C.; Orphanoudakis, S.C.; Markowitz, R.I.; Rosenfield, N.S.

    1983-07-01

    A digital video image processor, connected to a video system in a conventional pediatric fluoroscopy room, was used to determine whether the device could provide satisfactory fluoroscopic images during routine examinations when the x-ray tube was operated at substantially lower than normal radiation-dose levels. A 50% reduction resulted in image quality which was indistinguishable from conventional fluoroscopic views.

  3. Fluoroscopic chest tube insertion and patient care.

    PubMed Central

    Collins, J. D.; Shaver, M. L.; Disher, A. C.; Miller, T. Q.

    1992-01-01

    Catheters and chest tubes may be placed under fluoroscopic control to reduce pleural effusions. This procedure has been adopted as a routine procedure at the UCLA School of Medicine in Los Angeles, California to improve patient care. This technique was modified for the placement of large chest tubes, which can be placed by a radiologist without multiple attempts or complications. Our experience with 2234 patients who underwent this procedure between 1977 and 1990 is described. PMID:1404463

  4. Radiologic imaging technique

    SciTech Connect

    Bushong, S.C. ); Eastman, T.R. )

    1990-01-01

    The authors focus on the subject of clinical radiographic technique. Emphasizing correct radiographic technique, it's heavily illustrated with radiographs that demonstrate proper exposure and show what happens when exposure variables are changed. A key feature is a discussion and evaluation of radiographic technique charts. Basic technique charts are provided for every body part examined.

  5. Generation of fluoroscopic 3D images with a respiratory motion model based on an external surrogate signal.

    PubMed

    Hurwitz, Martina; Williams, Christopher L; Mishra, Pankaj; Rottmann, Joerg; Dhou, Salam; Wagar, Matthew; Mannarino, Edward G; Mak, Raymond H; Lewis, John H

    2015-01-21

    Respiratory motion during radiotherapy can cause uncertainties in definition of the target volume and in estimation of the dose delivered to the target and healthy tissue. In this paper, we generate volumetric images of the internal patient anatomy during treatment using only the motion of a surrogate signal. Pre-treatment four-dimensional CT imaging is used to create a patient-specific model correlating internal respiratory motion with the trajectory of an external surrogate placed on the chest. The performance of this model is assessed with digital and physical phantoms reproducing measured irregular patient breathing patterns. Ten patient breathing patterns are incorporated in a digital phantom. For each patient breathing pattern, the model is used to generate images over the course of thirty seconds. The tumor position predicted by the model is compared to ground truth information from the digital phantom. Over the ten patient breathing patterns, the average absolute error in the tumor centroid position predicted by the motion model is 1.4 mm. The corresponding error for one patient breathing pattern implemented in an anthropomorphic physical phantom was 0.6 mm. The global voxel intensity error was used to compare the full image to the ground truth and demonstrates good agreement between predicted and true images. The model also generates accurate predictions for breathing patterns with irregular phases or amplitudes.

  6. Generation of fluoroscopic 3D images with a respiratory motion model based on an external surrogate signal

    NASA Astrophysics Data System (ADS)

    Hurwitz, Martina; Williams, Christopher L.; Mishra, Pankaj; Rottmann, Joerg; Dhou, Salam; Wagar, Matthew; Mannarino, Edward G.; Mak, Raymond H.; Lewis, John H.

    2015-01-01

    Respiratory motion during radiotherapy can cause uncertainties in definition of the target volume and in estimation of the dose delivered to the target and healthy tissue. In this paper, we generate volumetric images of the internal patient anatomy during treatment using only the motion of a surrogate signal. Pre-treatment four-dimensional CT imaging is used to create a patient-specific model correlating internal respiratory motion with the trajectory of an external surrogate placed on the chest. The performance of this model is assessed with digital and physical phantoms reproducing measured irregular patient breathing patterns. Ten patient breathing patterns are incorporated in a digital phantom. For each patient breathing pattern, the model is used to generate images over the course of thirty seconds. The tumor position predicted by the model is compared to ground truth information from the digital phantom. Over the ten patient breathing patterns, the average absolute error in the tumor centroid position predicted by the motion model is 1.4 mm. The corresponding error for one patient breathing pattern implemented in an anthropomorphic physical phantom was 0.6 mm. The global voxel intensity error was used to compare the full image to the ground truth and demonstrates good agreement between predicted and true images. The model also generates accurate predictions for breathing patterns with irregular phases or amplitudes.

  7. A new tool for benchmarking cardiovascular fluoroscopes.

    PubMed

    Balter, S; Heupler, F A; Lin, P J; Wondrow, M H

    2001-01-01

    This article reports the status of a new cardiovascular fluoroscopy benchmarking phantom. A joint working group of the Society for Cardiac Angiography and Interventions (SCA&I) and the National Electrical Manufacturers Association (NEMA) developed the phantom. The device was adopted as NEMA standard XR 21-2000, "Characteristics of and Test Procedures for a Phantom to Benchmark Cardiac Fluoroscopic and Photographic Performance," in August 2000. The test ensemble includes imaging field geometry, spatial resolution, low-contrast iodine detectability, working thickness range, visibility of moving targets, and phantom entrance dose. The phantom tests systems under conditions simulating normal clinical use for fluoroscopically guided invasive and interventional procedures. Test procedures rely on trained human observers.

  8. Hybrid ultrasound imaging techniques (fusion imaging).

    PubMed

    Sandulescu, Daniela Larisa; Dumitrescu, Daniela; Rogoveanu, Ion; Saftoiu, Adrian

    2011-01-07

    Visualization of tumor angiogenesis can facilitate non-invasive evaluation of tumor vascular characteristics to supplement the conventional diagnostic imaging goals of depicting tumor location, size, and morphology. Hybrid imaging techniques combine anatomic [ultrasound, computed tomography (CT), and/or magnetic resonance imaging (MRI)] and molecular (single photon emission CT and positron emission tomography) imaging modalities. One example is real-time virtual sonography, which combines ultrasound (grayscale, colour Doppler, or dynamic contrast harmonic imaging) with contrast-enhanced CT/MRI. The benefits of fusion imaging include an increased diagnostic confidence, direct comparison of the lesions using different imaging modalities, more precise monitoring of interventional procedures, and reduced radiation exposure.

  9. Dose reduction technique using a combination of a region of interest (ROI) material x-ray attenuator and spatially different temporal filtering for fluoroscopic interventions

    NASA Astrophysics Data System (ADS)

    Swetadri Vasan, S. N.; Panse, A.; Jain, A.; Sharma, P.; Ionita, Ciprian N.; Titus, A. H.; Cartwright, A. N.; Bednarek, D. R.; Rudin, S.

    2012-03-01

    We demonstrate a novel approach for achieving patient dose savings during image-guided neurovascular interventions, involving a combination of a material x-ray region of interest (ROI) attenuator and a spatially different ROI temporal filtering technique. The part of the image under the attenuator is reduced in dose but noisy and less bright due to fewer x-ray quanta reaching the detector, as compared to the non-attenuating (or less attenuating) region. First the brightness is equalized throughout the image by post processing and then a temporal filter with higher weights is applied to the high attenuating region to reduce the noise, at the cost of increased lag; however, in the regions where less attenuation is present, a lower temporal weight is needed and is applied to preserve temporal resolution. A simulation of the technique is first presented on an actual image sequence obtained from an endovascular image guided interventional (EIGI) procedure. Then the actual implementation of the technique with a physical ROI attenuator is presented. Quantitative analysis including noise analysis and integral dose calculations are presented to validate the proposed technique.

  10. Dose Reduction Technique Using a Combination of a Region of Interest (ROI) Material X-Ray Attenuator and Spatially Different Temporal Filtering for Fluoroscopic Interventions

    PubMed Central

    Vasan, S.N Swetadri; Panse, A.; Jain, A.; Sharma, P.; Ionita, Ciprian N.; Titus, A.H.; Cartwright, A.N.; Bednarek, D.R; Rudin, S.

    2012-01-01

    We demonstrate a novel approach for achieving patient dose savings during image-guided neurovascular interventions, involving a combination of a material x-ray region of interest (ROI) attenuator and a spatially different ROI temporal filtering technique. The part of the image under the attenuator is reduced in dose but noisy and less bright due to fewer x-ray quanta reaching the detector, as compared to the non-attenuating (or less attenuating) region. First the brightness is equalized throughout the image by post processing and then a temporal filter with higher weights is applied to the high attenuating region to reduce the noise, at the cost of increased lag; however, in the regions where less attenuation is present, a lower temporal weight is needed and is applied to preserve temporal resolution. A simulation of the technique is first presented on an actual image sequence obtained from an endovascular image guided interventional (EIGI) procedure. Then the actual implementation of the technique with a physical ROI attenuator is presented. Quantitative analysis including noise analysis and integral dose calculations are presented to validate the proposed technique. PMID:24027617

  11. Dose Reduction Technique Using a Combination of a Region of Interest (ROI) Material X-Ray Attenuator and Spatially Different Temporal Filtering for Fluoroscopic Interventions.

    PubMed

    Vasan, S N Swetadri; Panse, A; Jain, A; Sharma, P; Ionita, Ciprian N; Titus, A H; Cartwright, A N; Bednarek, D R; Rudin, S

    2012-02-23

    We demonstrate a novel approach for achieving patient dose savings during image-guided neurovascular interventions, involving a combination of a material x-ray region of interest (ROI) attenuator and a spatially different ROI temporal filtering technique. The part of the image under the attenuator is reduced in dose but noisy and less bright due to fewer x-ray quanta reaching the detector, as compared to the non-attenuating (or less attenuating) region. First the brightness is equalized throughout the image by post processing and then a temporal filter with higher weights is applied to the high attenuating region to reduce the noise, at the cost of increased lag; however, in the regions where less attenuation is present, a lower temporal weight is needed and is applied to preserve temporal resolution. A simulation of the technique is first presented on an actual image sequence obtained from an endovascular image guided interventional (EIGI) procedure. Then the actual implementation of the technique with a physical ROI attenuator is presented. Quantitative analysis including noise analysis and integral dose calculations are presented to validate the proposed technique.

  12. Graphics Processing Unit (GPU) implementation of image processing algorithms to improve system performance of the Control, Acquisition, Processing, and Image Display System (CAPIDS) of the Micro-Angiographic Fluoroscope (MAF).

    PubMed

    Vasan, S N Swetadri; Ionita, Ciprian N; Titus, A H; Cartwright, A N; Bednarek, D R; Rudin, S

    2012-02-23

    We present the image processing upgrades implemented on a Graphics Processing Unit (GPU) in the Control, Acquisition, Processing, and Image Display System (CAPIDS) for the custom Micro-Angiographic Fluoroscope (MAF) detector. Most of the image processing currently implemented in the CAPIDS system is pixel independent; that is, the operation on each pixel is the same and the operation on one does not depend upon the result from the operation on the other, allowing the entire image to be processed in parallel. GPU hardware was developed for this kind of massive parallel processing implementation. Thus for an algorithm which has a high amount of parallelism, a GPU implementation is much faster than a CPU implementation. The image processing algorithm upgrades implemented on the CAPIDS system include flat field correction, temporal filtering, image subtraction, roadmap mask generation and display window and leveling. A comparison between the previous and the upgraded version of CAPIDS has been presented, to demonstrate how the improvement is achieved. By performing the image processing on a GPU, significant improvements (with respect to timing or frame rate) have been achieved, including stable operation of the system at 30 fps during a fluoroscopy run, a DSA run, a roadmap procedure and automatic image windowing and leveling during each frame.

  13. Graphics processing unit (GPU) implementation of image processing algorithms to improve system performance of the control acquisition, processing, and image display system (CAPIDS) of the micro-angiographic fluoroscope (MAF)

    NASA Astrophysics Data System (ADS)

    Swetadri Vasan, S. N.; Ionita, Ciprian N.; Titus, A. H.; Cartwright, A. N.; Bednarek, D. R.; Rudin, S.

    2012-03-01

    We present the image processing upgrades implemented on a Graphics Processing Unit (GPU) in the Control, Acquisition, Processing, and Image Display System (CAPIDS) for the custom Micro-Angiographic Fluoroscope (MAF) detector. Most of the image processing currently implemented in the CAPIDS system is pixel independent; that is, the operation on each pixel is the same and the operation on one does not depend upon the result from the operation on the other, allowing the entire image to be processed in parallel. GPU hardware was developed for this kind of massive parallel processing implementation. Thus for an algorithm which has a high amount of parallelism, a GPU implementation is much faster than a CPU implementation. The image processing algorithm upgrades implemented on the CAPIDS system include flat field correction, temporal filtering, image subtraction, roadmap mask generation and display window and leveling. A comparison between the previous and the upgraded version of CAPIDS has been presented, to demonstrate how the improvement is achieved. By performing the image processing on a GPU, significant improvements (with respect to timing or frame rate) have been achieved, including stable operation of the system at 30 fps during a fluoroscopy run, a DSA run, a roadmap procedure and automatic image windowing and leveling during each frame.

  14. Sensor image prediction techniques

    NASA Astrophysics Data System (ADS)

    Stenger, A. J.; Stone, W. R.; Berry, L.; Murray, T. J.

    1981-02-01

    The preparation of prediction imagery is a complex, costly, and time consuming process. Image prediction systems which produce a detailed replica of the image area require the extensive Defense Mapping Agency data base. The purpose of this study was to analyze the use of image predictions in order to determine whether a reduced set of more compact image features contains enough information to produce acceptable navigator performance. A job analysis of the navigator's mission tasks was performed. It showed that the cognitive and perceptual tasks he performs during navigation are identical to those performed for the targeting mission function. In addition, the results of the analysis of his performance when using a particular sensor can be extended to the analysis of this mission tasks using any sensor. An experimental approach was used to determine the relationship between navigator performance and the type of amount of information in the prediction image. A number of subjects were given image predictions containing varying levels of scene detail and different image features, and then asked to identify the predicted targets in corresponding dynamic flight sequences over scenes of cultural, terrain, and mixed (both cultural and terrain) content.

  15. A computational hyperspectral imaging technique

    NASA Astrophysics Data System (ADS)

    Habibi, Nasim; Azari, Mohammad; Abolbashari, Mehrdad; Farahi, Faramarz

    2016-03-01

    A novel spectral imaging technique is introduced based on a highly dispersive imaging lens system. The chromatic aberration of the lens system is utilized to spread the spectral content of the object over a focal distance. Two three-dimensional surface reconstruction algorithms, depth from focus and depth from defocus, are applied to images captured by dispersive lens system. Using these algorithms, the spectral imager is able to relate either the location of focused image or the amount of defocus at the imaging detector to the spectral content of the object. A spectral imager with ~5 nm spectral resolution is designed based on this technique. The spectral and spatial resolutions of the introduced technique are independent and can be improved simultaneously. Simulation and experimental results are presented.

  16. Eye Redness Image Processing Techniques

    NASA Astrophysics Data System (ADS)

    Adnan, M. R. H. Mohd; Zain, Azlan Mohd; Haron, Habibollah; Alwee, Razana; Zulfaezal Che Azemin, Mohd; Osman Ibrahim, Ashraf

    2017-09-01

    The use of photographs for the assessment of ocular conditions has been suggested to further standardize clinical procedures. The selection of the photographs to be used as scale reference images was subjective. Numerous methods have been proposed to assign eye redness scores by computational methods. Image analysis techniques have been investigated over the last 20 years in an attempt to forgo subjective grading scales. Image segmentation is one of the most important and challenging problems in image processing. This paper briefly outlines the comprehensive of image processing and the implementation of image segmentation in eye redness.

  17. EDITORIAL: Imaging Systems and Techniques Imaging Systems and Techniques

    NASA Astrophysics Data System (ADS)

    Giakos, George; Yang, Wuqiang; Petrou, M.; Nikita, K. S.; Pastorino, M.; Amanatiadis, A.; Zentai, G.

    2011-10-01

    This special feature on Imaging Systems and Techniques comprises 27 technical papers, covering essential facets in imaging systems and techniques both in theory and applications, from research groups spanning three different continents. It mainly contains peer-reviewed articles from the IEEE International Conference on Imaging Systems and Techniques (IST 2011), held in Thessaloniki, Greece, as well a number of articles relevant to the scope of this issue. The multifaceted field of imaging requires drastic adaptation to the rapid changes in our society, economy, environment, and the technological revolution; there is an urgent need to address and propose dynamic and innovative solutions to problems that tend to be either complex and static or rapidly evolving with a lot of unknowns. For instance, exploration of the engineering and physical principles of new imaging systems and techniques for medical applications, remote sensing, monitoring of space resources and enhanced awareness, exploration and management of natural resources, and environmental monitoring, are some of the areas that need to be addressed with urgency. Similarly, the development of efficient medical imaging techniques capable of providing physiological information at the molecular level is another important area of research. Advanced metabolic and functional imaging techniques, operating on multiple physical principles, using high resolution and high selectivity nanoimaging techniques, can play an important role in the diagnosis and treatment of cancer, as well as provide efficient drug-delivery imaging solutions for disease treatment with increased sensitivity and specificity. On the other hand, technical advances in the development of efficient digital imaging systems and techniques and tomographic devices operating on electric impedance tomography, computed tomography, single-photon emission and positron emission tomography detection principles are anticipated to have a significant impact on a

  18. Implementation of a high-sensitivity Micro-Angiographic Fluoroscope (HS-MAF) for in-vivo endovascular image guided interventions (EIGI) and region-of-interest computed tomography (ROI-CT).

    PubMed

    Ionita, C N; Keleshis, C; Patel, V; Yadava, G; Hoffmann, K R; Bednarek, D R; Jain, A; Rudin, S

    2008-01-01

    New advances in catheter technology and remote actuation for minimally invasive procedures are continuously increasing the demand for better x-ray imaging technology. The new x-ray high-sensitivity Micro-Angiographic Fluoroscope (HS-MAF) detector offers high resolution and real-time image-guided capabilities which are unique when compared with commercially available detectors. This detector consists of a 300 μm CsI input phosphor coupled to a dual stage GEN2 micro-channel plate light image intensifier (LII), followed by minifying fiber-optic taper coupled to a CCD chip. The HS-MAF detector image array is 1024×1024 pixels, with a 12 bit depth capable of imaging at 30 frames per second. The detector has a round field of view with 4 cm diameter and 35 microns pixels. The LII has a large variable gain which allows usage of the detector at very low exposures characteristic of fluoroscopic ranges while maintaining very good image quality. The custom acquisition program allows real-time image display and data storage. We designed a set of in-vivo experimental interventions in which placement of specially designed endovascular stents were evaluated with the new detector and with a standard x-ray image intensifier (XII). Capabilities such fluoroscopy, angiography and ROI-CT reconstruction using rotational angiography data were implemented and verified. The images obtained during interventions under radiographic control with the HS-MAF detector were superior to those with the XII. In general, the device feature markers, the device structures, and the vessel geometry were better identified with the new detector. High-resolution detectors such as HS-MAF can vastly improve the accuracy of localization and tracking of devices such stents or catheters.

  19. Simultaneous multislice (SMS) imaging techniques

    PubMed Central

    Barth, Markus; Breuer, Felix; Koopmans, Peter J.; Poser, Benedikt A.

    2015-01-01

    Simultaneous multislice imaging (SMS) using parallel image reconstruction has rapidly advanced to become a major imaging technique. The primary benefit is an acceleration in data acquisition that is equal to the number of simultaneously excited slices. Unlike in‐plane parallel imaging this can have only a marginal intrinsic signal‐to‐noise ratio penalty, and the full acceleration is attainable at fixed echo time, as is required for many echo planar imaging applications. Furthermore, for some implementations SMS techniques can reduce radiofrequency (RF) power deposition. In this review the current state of the art of SMS imaging is presented. In the Introduction, a historical overview is given of the history of SMS excitation in MRI. The following section on RF pulses gives both the theoretical background and practical application. The section on encoding and reconstruction shows how the collapsed multislice images can be disentangled by means of the transmitter pulse phase, gradient pulses, and most importantly using multichannel receiver coils. The relationship between classic parallel imaging techniques and SMS reconstruction methods is explored. The subsequent section describes the practical implementation, including the acquisition of reference data, and slice cross‐talk. Published applications of SMS imaging are then reviewed, and the article concludes with an outlook and perspective of SMS imaging. Magn Reson Med 75:63–81, 2016. © 2015 The Authors. Magnetic Resonance in Medicine Published by Wiley Periodicals, Inc. on behalf of International Society of Medicine in Resonance. PMID:26308571

  20. Simultaneous multislice (SMS) imaging techniques.

    PubMed

    Barth, Markus; Breuer, Felix; Koopmans, Peter J; Norris, David G; Poser, Benedikt A

    2016-01-01

    Simultaneous multislice imaging (SMS) using parallel image reconstruction has rapidly advanced to become a major imaging technique. The primary benefit is an acceleration in data acquisition that is equal to the number of simultaneously excited slices. Unlike in-plane parallel imaging this can have only a marginal intrinsic signal-to-noise ratio penalty, and the full acceleration is attainable at fixed echo time, as is required for many echo planar imaging applications. Furthermore, for some implementations SMS techniques can reduce radiofrequency (RF) power deposition. In this review the current state of the art of SMS imaging is presented. In the Introduction, a historical overview is given of the history of SMS excitation in MRI. The following section on RF pulses gives both the theoretical background and practical application. The section on encoding and reconstruction shows how the collapsed multislice images can be disentangled by means of the transmitter pulse phase, gradient pulses, and most importantly using multichannel receiver coils. The relationship between classic parallel imaging techniques and SMS reconstruction methods is explored. The subsequent section describes the practical implementation, including the acquisition of reference data, and slice cross-talk. Published applications of SMS imaging are then reviewed, and the article concludes with an outlook and perspective of SMS imaging. © 2015 Wiley Periodicals, Inc.

  1. Automated medical image segmentation techniques

    PubMed Central

    Sharma, Neeraj; Aggarwal, Lalit M.

    2010-01-01

    Accurate segmentation of medical images is a key step in contouring during radiotherapy planning. Computed topography (CT) and Magnetic resonance (MR) imaging are the most widely used radiographic techniques in diagnosis, clinical studies and treatment planning. This review provides details of automated segmentation methods, specifically discussed in the context of CT and MR images. The motive is to discuss the problems encountered in segmentation of CT and MR images, and the relative merits and limitations of methods currently available for segmentation of medical images. PMID:20177565

  2. Automated medical image segmentation techniques.

    PubMed

    Sharma, Neeraj; Aggarwal, Lalit M

    2010-01-01

    Accurate segmentation of medical images is a key step in contouring during radiotherapy planning. Computed topography (CT) and Magnetic resonance (MR) imaging are the most widely used radiographic techniques in diagnosis, clinical studies and treatment planning. This review provides details of automated segmentation methods, specifically discussed in the context of CT and MR images. The motive is to discuss the problems encountered in segmentation of CT and MR images, and the relative merits and limitations of methods currently available for segmentation of medical images.

  3. 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

    A new dual detector system was developed which utilizes a low resolution, large field-of-view x-ray image intensifier (II) and a high resolution, region-of-interest microangiographic (MA) detector on the same c-arm gantry. With this new MA-II system, the larger field-of-view (FOV) II can be operated when the demands of the task are not as high, and a larger imaging area is desired. However, when a higher-resolution image with greater image quality is desired at a targeted region-of-interest (ROI), the MA can be deployed to take on these greater demands. To quantitatively and qualitatively assess the imaging performance of each detector under realistic conditions, angiographic images of simulated vessels and rabbit neurovasculature were acquired with both detectors under nearly identical conditions. With the MA detector deployed, vessels as small as 95 mum were visible, whereas the II could not detect vessels smaller than 235 mum. The ROI MA mode was also shown to provide sharper images with higher contrast-to-noise ratios and was four times as likely to successfully detect overlapping vessels as compared to the II. More accurate three-dimensional center lines of vasculature using multi-view reconstruction techniques were also obtained with the MA. The solid state x-ray image intensifier (SSXII) was developed to provide similar high-resolution imaging capabilities as the MA and a built in adjustable gain to provide high-sensitivity imaging capabilities for operation at all exposures used in medical x-ray imaging procedures. The imaging components used in construction of the prototype SSXII were selected based on a theoretical performance evaluation, using a Fourier-based linear-systems model analysis. The performance of the prototype SSXII was then extensively evaluated. Images of various objects and image comparisons with current state-of-the-art detectors qualitatively demonstrated that the SSXII is capable of providing substantial improvements. A quantitative

  4. ALARA in pediatric interventional and fluoroscopic imaging: striving to keep radiation doses as low as possible during fluoroscopy of pediatric patients--a white paper executive summary.

    PubMed

    Strauss, Keith J; Kaste, Sue C

    2006-09-01

    Pediatric patients might be as much as 10 times more radiosensitive than adults. Thus, adherence to the principle of "As low as reasonably achievable" (ALARA) represents a practice mandate that minimizes ionizing radiation exposure while optimizing imaging results. This symposium is the third multidisciplinary program that focused on the ALARA principle in pediatric imaging and addressed issues associated with pediatric fluoroscopy and interventional imaging techniques.

  5. Urologic imaging and interventional techniques

    SciTech Connect

    Bush, W.H.

    1989-01-01

    This book provides an overview of all imaging modalities and invasive techniques of the genitourinary system. Three general chapters discuss ionic and nonionic contrast media, the management of reactions to contrast media, and radiation doses from various uroradiologic procedures. Chapters are devoted to intravenous pyelography, computed tomography, magnetic resonance imaging, ultrasound, nuclear medicine, lymphography, arteriography, and venography. Two chapters discuss the pediatric applications of uroradiology and ultrasound. Two chapters integrate the various imaging techniques of the upper and lower genitourinary systems into an algorithmic approach for various pathologic entities.

  6. Fluoroscopic tomography. [for body section synthesis

    NASA Technical Reports Server (NTRS)

    Baily, N. A.; Crepeau, R. L.; Lasser, E. C.

    1974-01-01

    A fluoroscopic tomography system capable of synthesizing body sections at a number of levels within the body has been developed. The synthesized body sections may lie either in a range of planes parallel to, tilted with respect to, skewed with respect to, or both tilted and skewed with respect to the plane of motion of the X-ray tube target. In addition, body sections can be presented which are contoured to the patient's anatomy. That is to say, they may even encompass such complex surfaces as a quadratic hyperplane. In addition, tomograms of organs in motion can be imaged.

  7. Functionality and operation of fluoroscopic automatic brightness control/automatic dose rate control logic in modern cardiovascular and interventional angiography systems: A Report of Task Group 125 Radiography/Fluoroscopy Subcommittee, Imaging Physics Committee, Science Council

    SciTech Connect

    Rauch, Phillip; Lin, Pei-Jan Paul; Balter, Stephen; Fukuda, Atsushi; Goode, Allen; Hartwell, Gary; LaFrance, Terry; Nickoloff, Edward; Shepard, Jeff; Strauss, Keith

    2012-05-15

    Task Group 125 (TG 125) was charged with investigating the functionality of fluoroscopic automatic dose rate and image quality control logic in modern angiographic systems, paying specific attention to the spectral shaping filters and variations in the selected radiologic imaging parameters. The task group was also charged with describing the operational aspects of the imaging equipment for the purpose of assisting the clinical medical physicist with clinical set-up and performance evaluation. Although there are clear distinctions between the fluoroscopic operation of an angiographic system and its acquisition modes (digital cine, digital angiography, digital subtraction angiography, etc.), the scope of this work was limited to the fluoroscopic operation of the systems studied. The use of spectral shaping filters in cardiovascular and interventional angiography equipment has been shown to reduce patient dose. If the imaging control algorithm were programmed to work in conjunction with the selected spectral filter, and if the generator parameters were optimized for the selected filter, then image quality could also be improved. Although assessment of image quality was not included as part of this report, it was recognized that for fluoroscopic imaging the parameters that influence radiation output, differential absorption, and patient dose are also the same parameters that influence image quality. Therefore, this report will utilize the terminology ''automatic dose rate and image quality'' (ADRIQ) when describing the control logic in modern interventional angiographic systems and, where relevant, will describe the influence of controlled parameters on the subsequent image quality. A total of 22 angiography units were investigated by the task group and of these one each was chosen as representative of the equipment manufactured by GE Healthcare, Philips Medical Systems, Shimadzu Medical USA, and Siemens Medical Systems. All equipment, for which measurement data were

  8. Functionality and operation of fluoroscopic automatic brightness control/automatic dose rate control logic in modern cardiovascular and interventional angiography systems: a report of Task Group 125 Radiography/Fluoroscopy Subcommittee, Imaging Physics Committee, Science Council.

    PubMed

    Rauch, Phillip; Lin, Pei-Jan Paul; Balter, Stephen; Fukuda, Atsushi; Goode, Allen; Hartwell, Gary; LaFrance, Terry; Nickoloff, Edward; Shepard, Jeff; Strauss, Keith

    2012-05-01

    Task Group 125 (TG 125) was charged with investigating the functionality of fluoroscopic automatic dose rate and image quality control logic in modern angiographic systems, paying specific attention to the spectral shaping filters and variations in the selected radiologic imaging parameters. The task group was also charged with describing the operational aspects of the imaging equipment for the purpose of assisting the clinical medical physicist with clinical set-up and performance evaluation. Although there are clear distinctions between the fluoroscopic operation of an angiographic system and its acquisition modes (digital cine, digital angiography, digital subtraction angiography, etc.), the scope of this work was limited to the fluoroscopic operation of the systems studied. The use of spectral shaping filters in cardiovascular and interventional angiography equipment has been shown to reduce patient dose. If the imaging control algorithm were programmed to work in conjunction with the selected spectral filter, and if the generator parameters were optimized for the selected filter, then image quality could also be improved. Although assessment of image quality was not included as part of this report, it was recognized that for fluoroscopic imaging the parameters that influence radiation output, differential absorption, and patient dose are also the same parameters that influence image quality. Therefore, this report will utilize the terminology "automatic dose rate and image quality" (ADRIQ) when describing the control logic in modern interventional angiographic systems and, where relevant, will describe the influence of controlled parameters on the subsequent image quality. A total of 22 angiography units were investigated by the task group and of these one each was chosen as representative of the equipment manufactured by GE Healthcare, Philips Medical Systems, Shimadzu Medical USA, and Siemens Medical Systems. All equipment, for which measurement data were

  9. Intraoperative fluoroscopic dose assessment in prostate brachytherapy patients.

    PubMed

    Reed, Daniel R; Wallner, Kent E; Narayanan, Sreeram; Sutlief, Steve G; Ford, Eric C; Cho, Paul S

    2005-09-01

    To evaluate a fluoroscopy-based intraoperative dosimetry system to guide placement of additional sources to underdosed areas, and perform computed tomography (CT) verification. Twenty-six patients with prostate carcinoma treated with either I-125 or Pd-103 brachytherapy at the Puget Sound VA using intraoperative postimplant dosimetry were analyzed. Implants were performed by standard techniques. After completion of the initial planned brachytherapy procedure, the initial fluoroscopic intraoperative dose reconstruction analysis (I-FL) was performed with three fluoroscopic images acquired at 0 (AP), +15, and -15 degrees. Automatic seed identification was performed and the three-dimensional (3D) seed coordinates were computed and imported into VariSeed for dose visualization. Based on a 3D assessment of the isodose patterns additional seeds were implanted, and the final fluoroscopic intraoperative dose reconstruction was performed (FL). A postimplant computed tomography (CT) scan was obtained after the procedure and dosimetric parameters and isodose patterns were analyzed and compared. An average of 4.7 additional seeds were implanted after intraoperative analysis of the dose coverage (I-FL), and a median of 5 seeds. After implantation of additional seeds the mean V100 increased from 89% (I-FL) to 92% (FL) (p < 0.001). In I-125 patients an improvement from 91% to 94% (p = 0.01), and 87% to 93% (p = 0.001) was seen for Pd-103. The D90 increased from 105% (I-FL) to 122% (FL) (p < 0.001) for I-125, and 92% (I-FL) to 102% (FL) (p = 0.008) for Pd-103. A minimal change occurred in the R100 from a mean of 0.32 mL (I-FL) to 0.6 mL (FL) (p = 0.19). No statistical difference was noted in the R100 (rectal volume receiving 100% of the prescribed dose) between the two techniques. The rate of adverse isodose patterns decreased between I-FL and FL from 42% to 8%, respectively. The I-125 patients demonstrated a complete resolution of adverse isodose patterns after the initial isodose

  10. EDITORIAL: Imaging systems and techniques Imaging systems and techniques

    NASA Astrophysics Data System (ADS)

    Yang, Wuqiang; Giakos, George; Nikita, Konstantina; Pastorino, Matteo; Karras, Dimitrios

    2009-10-01

    The papers in this special issue focus on providing the state-of-the-art approaches and solutions to some of the most challenging imaging areas, such as the design, development, evaluation and applications of imaging systems, measuring techniques, image processing algorithms and instrumentation, with an ultimate aim of enhancing the measurement accuracy and image quality. This special issue explores the principles, engineering developments and applications of new imaging systems and techniques, and encourages broad discussion of imaging methodologies, shaping the future and identifying emerging trends. The multi-faceted field of imaging requires drastic adaptation to the rapid changes in our society, economy, environment and technological evolution. There is an urgent need to address new problems, which tend to be either static but complex, or dynamic, e.g. rapidly evolving with time, with many unknowns, and to propose innovative solutions. For instance, the battles against cancer and terror, monitoring of space resources and enhanced awareness, management of natural resources and environmental monitoring are some of the areas that need to be addressed. The complexity of the involved imaging scenarios and demanding design parameters, e.g. speed, signal-to-noise ratio (SNR), specificity, contrast, spatial resolution, scatter rejection, complex background and harsh environments, necessitate the development of a multi-functional, scalable and efficient imaging suite of sensors, solutions driven by innovation, and operation on diverse detection and imaging principles. Efficient medical imaging techniques capable of providing physiological information at the molecular level present another important research area. Advanced metabolic and functional imaging techniques, operating on multiple physical principles, and using high-resolution, high-selectivity nano-imaging methods, quantum dots, nanoparticles, biomarkers, nanostructures, nanosensors, micro-array imaging chips

  11. Morphological image processing techniques in thermographic imaging.

    PubMed

    Schulze, M A; Pearce, J A

    1993-01-01

    Mathematical morphology is a set algebra that defines some important new techniques in image processing. Morphological filters are closely related to order statistic and other nonlinear filters, but they are uniquely sensitive to shape. A morphological filter will preserve shapes similar to its structuring element shape while modifying dissimilar shapes. Most morphological filters are effective at removing both linear and nonlinear noise processes. However, the standard morphological operators introduce a statistical and deterministic bias to images. Fortunately, these operators exist in complementary pairs that are equally and oppositely biased. One way to alleviate the bias is to average the two complementary operators. The filters formed by such averages are the midrange filter (basic operators), the pseudomedian filter (singly compound operators) and the LOCO filter (doubly compound operators). In thermographic imaging, one often wishes to find exact temperatures or accurate isothermal contours. Therefore, techniques used to remove sensor noise and scanning artifact should not introduce bias. The LOCO filter that we have devised provides the shape control and noise suppression of morphological techniques without biasing the image. We will demonstrate the effects of different structuring element shapes on thermographic images of tissue heated by laser irradiation and electrosurgery.

  12. Posterior atlantoaxial fixation: A cadaveric and fluoroscopic step-by-step technical guide.

    PubMed

    Sattarov, Kamran; Skoch, Jesse; Abbasifard, Salman; Patel, Apar S; Avila, Mauricio J; Walter, Christina M; Baaj, Ali A

    2015-01-01

    Atlantoaxial surgical fixation is widely employed treatment strategy for a myriad of pathologies affecting the stability of the atlantoaxial joint. The most common technique used in adults, and in certain cases in children, involves a posterior construct with C1 lateral mass screws, and C2 pars or pedicle screws. This technical note aims to provide a step-by-step guide to this procedure using cadaveric and fluoroscopic images. An embalmed, human, cadaveric, specimen was used for this study. The subject did not have obvious occipital-cervical pathology. Dissections and techniques were performed to mimic actual surgical technique. Photographs were taken during each step, and the critical aspects of each step were highlighted. Fluoroscopic images from a real patient undergoing C1/C2 fixation were also utilized to further highlight the anatomic-radiographic relationships. This study was performed without external or industry funding. Photographic and radiographic pictures and drawings are presented to illustrate the pertinent anatomy and technical aspects of this technique. The nuances of each step, including complication avoidance strategies are also highlighted. Given the widespread utilization of this technique, described step-by-step guide is timely for surgeons and trainees alike.

  13. Diagnostic cardiology: Noninvasive imaging techniques

    SciTech Connect

    Come, P.C.

    1985-01-01

    This book contains 23 chapters. Some of the chapter titles are: The chest x-ray and cardiac series; Computed tomographic scanning of the heart, coronary arteries, and great vessels; Digital subtraction angiography in the assessment of cardiovascular disease; Magnetic resonance: technique and cardiac applications; Basics of radiation physics and instrumentation; and Nuclear imaging: the assessment of cardiac performance.

  14. Improving accuracy of markerless tracking of lung tumours in fluoroscopic video by incorporating diaphragm motion

    NASA Astrophysics Data System (ADS)

    Schwarz, M.; Teske, H.; Stoll, M.; Bendl, Rolf

    2014-03-01

    Purpose: Conformal radiation of moving tumours is a challenging task in radiotherapy. Tumour motion induced by respiration can be visualized in fluoroscopic images recorded during patients breathing. Markerless methods making use of registration techniques can be used to estimate tumour motion. However, registration methods might fail when the tumour is hidden by ribs. Using motion of anatomical surrogates, like the diaphragm, is promising to model tumour motion. Methods: A sequence of 116 fluoroscopic images was analyzed and the tumour positions were manually defined by three experts. A block matching (BM) technique is used to calculate the displacement vector relatively to a selected reference image of the first breathing cycle. An enhanced method was developed: Positions, when the tumour is not located behind a rib, are taken as valid estimations of the tumour position. Furthermore, these valid estimations are used to establish a linear model of tumour position and diaphragm motion. For invalid estimations the calculated tumour positions are not taken into consideration, and instead the model is used to determine tumour motion. Results: Enhancing BM with a model of tumour motion from diaphragm motion improves the tracking accuracy when the tumour moves behind a rib. The error (mean ± SD) in longitudinal dimension was 2.0 ± 1.5mm using only BM and 1.0 ± 1.1mm when the enhanced approach was used. Conclusion: The enhanced tracking technique is capable to improve tracking accuracy compared to BM in the case that the tumour is occluded by ribs.

  15. Integration of kerma-area product and cumulative air kerma determination into a skin dose tracking system for fluoroscopic imaging procedures

    NASA Astrophysics Data System (ADS)

    Vijayan, Sarath; Shankar, Alok; Rudin, Stephen; Bednarek, Daniel R.

    2016-03-01

    The skin dose tracking system (DTS) that we developed provides a color-coded mapping of the cumulative skin dose distribution on a 3D graphic of the patient during fluoroscopic procedures in real time. The DTS has now been modified to also calculate the kerma area product (KAP) and cumulative air kerma (CAK) for fluoroscopic interventions using data obtained in real-time from the digital bus on a Toshiba Infinix system. KAP is the integral of air kerma over the beam area and is typically measured with a large-area transmission ionization chamber incorporated into the collimator assembly. In this software, KAP is automatically determined for each x-ray pulse as the product of the air kerma/ mAs from a calibration file for the given kVp and beam filtration times the mAs per pulse times the length and width of the beam times a field nonuniformity correction factor. Field nonuniformity is primarily the result of the heel effect and the correction factor was determined from the beam profile measured using radio-chromic film. Dividing the KAP by the beam area at the interventional reference point provides the area averaged CAK. The KAP and CAK per x-ray pulse are summed after each pulse to obtain the total procedure values in real-time. The calculated KAP and CAK were compared to the values displayed by the fluoroscopy machine with excellent agreement. The DTS now is able to automatically calculate both KAP and CAK without the need for measurement by an add-on transmission ionization chamber.

  16. Neurophysiological imaging techniques in dementia.

    PubMed

    Comi, G; Leocani, L

    1999-01-01

    Neurophysiological methods, such as electroencephalography (EEG) and event-related potentials, are useful tools in the investigation of brain cognitive function in normal and pathological conditions, with an excellent time resolution when compared to that of other functional imaging techniques. Advanced techniques using a high number of EEG channels also enable a good spatial resolution to be achieved. This, together with the possibility of integration with other anatomical and functional images, may increase the ability to localize brain functions. Spectral analysis of the resting EEG, which gives information on the integrity of the cortical and subcortical networks involved in the generation of cortical rhythms, has the limitation of low sensitivity and specificity for the type of cognitive impairment. In almost all types of dementia, decreased power of the high frequencies is indeed observed in mild stages, accompanied by increased power of the slow rhythms in the more advanced phases. The sensitivity for the detection of spectral abnormalities is improved by studying centroid modifications. More specific information on the type of dementia can be provided by coherence analysis of the resting EEG, a measure of functional cortico-cortical connections, which has different abnormal patterns in Alzheimer's disease, cerebrovascular dementia and dementia associated with multiple sclerosis. Another tool for improving the assessment of demented patients is the study of EEG activity related to particular tasks, such as event-related potentials and event-related desynchronization/synchronization of the EEG, which allow the study of brain activation during cognitive and motor tasks.

  17. Imaging techniques for myocardial inflammation

    SciTech Connect

    O'Connell, J.B.; Henkin, R.E.; Robinson, J.A.

    1986-03-01

    Dilated cardiomyopathy (DC) represents a heterogeneous group of disorders which results in morbidity and mortality in young individuals. Recent evidence suggests that a subset of these patients have histologic evidence of myocarditis which is potentially treatable with immunosuppression. The identification of myocardial inflammation may therefore lead to development of therapeutic regimens designed to treat the cause rather than the effect of the myocardial disease. Ultimately, this may result in improvement in the abysmal prognosis of DC. The currently accepted technique for identification of active myocardial inflammation is endomyocardial biopsy. This technique is not perfect, however, since pathologic standards for the diagnosis of myocarditis have not been established. Furthermore, focal inflammation may give rise to sampling error. The inflammation-avid radioisotope gallium-67 citrate has been used as an adjunct to biopsy improving the yield of myocarditis from 7 percent to 36 percent. Serial imaging correlates well to biopsy results. Future studies are designed to study the applicability of lymphocyte labelling techniques to myocardial inflammatory disease.

  18. Imaging techniques in biology and medicine

    SciTech Connect

    Swenberg, C.E.

    1988-01-01

    This book serves as an introduction to some aspects of imaging techniques as utilized in biology and medicine. Techniques presented include image processing, ultrasound, radiotracers, autoradiography, computed tomography, and MRI (all major imaging techniques). The underlying mathematics and physics are kept to a minimum.

  19. Estimates of diagnostic reference levels for pediatric peripheral and abdominal fluoroscopically guided procedures.

    PubMed

    Strauss, Keith J; Racadio, John M; Johnson, Neil; Patel, Manish; Nachabe, Rami A

    2015-06-01

    The objective of our study was to survey radiation dose indexes of pediatric peripheral and abdominal fluoroscopically guided procedures from which estimates of diagnostic reference levels (DRLs) can be proposed for both a standard fluoroscope and a novel fluoroscope with advanced image processing and lower radiation dose rates. Radiation dose structured reports were retrospectively collected for 408 clinical pediatric cases: Half of the procedures were performed with a standard imaging technology and half with a novel x-ray technology. Dose-area product (DAP), air Kerma (AK), fluoroscopy time, number of digital subtraction angiography images, and patient mass were collected to calculate and normalize radiation dose indexes for procedures completed with the standard and novel fluoroscopes. The study population was composed of 180 and 175 patients who underwent procedures with the standard and novel technology, respectively. The 21 different types of pediatric peripheral and abdominal interventional procedures produced 408 total studies. Median ages, mass and body mass index, fluoroscopy time per procedure, and total number of recorded images for the standard and novel technologies were not statistically different. The area of the x-ray beams was square at the level of the patient with a dimension of 10-13 cm. The dose reduction achieved with the novel fluoroscope ranged from 18% to 51% of the dose required with the standard fluoroscope. The median DAP and AK patient dose indexes were 0.38 Gy · cm(2) and 4.00 mGy, respectively, for the novel fluoroscope. Estimates of dose indexes of pediatric peripheral and abdominal fluoroscopically guided, clinical procedures should assist in the development of DRLs to foster management of radiation doses of pediatric patients.

  20. Tooling Techniques Enhance Medical Imaging

    NASA Technical Reports Server (NTRS)

    2012-01-01

    mission. The manufacturing techniques developed to create the components have yielded innovations advancing medical imaging, transportation security, and even energy efficiency.

  1. Biplane reconstruction and visualization of virtual endoscopic and fluoroscopic views for interventional device navigation

    NASA Astrophysics Data System (ADS)

    Wagner, Martin G.; Strother, Charles M.; Schafer, Sebastian; Mistretta, Charles A.

    2016-03-01

    Biplane fluoroscopic imaging is an important tool for minimally invasive procedures for the treatment of cerebrovascular diseases. However, finding a good working angle for the C-arms of the angiography system as well as navigating based on the 2D projection images can be a difficult task. The purpose of this work is to propose a novel 4D reconstruction algorithm for interventional devices from biplane fluoroscopy images and to propose new techniques for a better visualization of the results. The proposed reconstruction methods binarizes the fluoroscopic images using a dedicated noise reduction algorithm for curvilinear structures and a global thresholding approach. A topology preserving thinning algorithm is then applied and a path search algorithm minimizing the curvature of the device is used to extract the 2D device centerlines. Finally, the 3D device path is reconstructed using epipolar geometry. The point correspondences are determined by a monotonic mapping function that minimizes the reconstruction error. The three dimensional reconstruction of the device path allows the rendering of virtual fluoroscopy images from arbitrary angles as well as 3D visualizations like virtual endoscopic views or glass pipe renderings, where the vessel wall is rendered with a semi-transparent material. This work also proposes a combination of different visualization techniques in order to increase the usability and spatial orientation for the user. A combination of synchronized endoscopic and glass pipe views is proposed, where the virtual endoscopic camera position is determined based on the device tip location as well as the previous camera position using a Kalman filter in order to create a smooth path. Additionally, vessel centerlines are displayed and the path to the target is highlighted. Finally, the virtual endoscopic camera position is also visualized in the glass pipe view to further improve the spatial orientation. The proposed techniques could considerably improve

  2. Bayes Syndrome and Imaging Techniques.

    PubMed

    Betancor, Ivan Hernandez; Izquierdo-Gomez, Maria Manuela; Niebla, Javier Garcia; Laynez-Cerdeña, Ignacio; Garcia-Gonzalez, Martin Jesus; Barragan-Acea, Antonio; Iribarren-Sarriá, Jose Luis; Jimenez-Rivera, Juan Jose; Lacalzada-Almeida, Juan

    2017-07-13

    Interatrial block (IAB) is due to disruption in the Bachmann region (BR). According to whether interatrial electrical conduction is delayed or completely blocked through the BR, it can be classified as IAB of first, second or third degree. On the surface electrocardiogram, a P wave ≥ 120 ms (partial IAB) is observed or associated to the prolongation of the P wave with a biphasic (positive / negative) morphology in the inferior leads (advanced IAB). Bayes syndrome is defined as an advanced IAB associated with atrial arrhythmia, more specifically atrial fibrillation. The purpose of this review is to describe the latest evidence about an entity considered an anatomical and electrical substrate with its own name, which may be a predictor of supraventricular arrhythmia and cardioembolic cerebrovascular accidents, as well as the role of new imaging techniques, such as echocardiographic strain and cardiac magnetic resonance imaging, in characterizing atrial alterations associated with this syndrome and generally in the study of anatomy and atrial function. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Bone fragility and imaging techniques

    PubMed Central

    D’Elia, Giovanni; Caracchini, Giuseppe; Cavalli, Loredana; Innocenti, Paolo

    2009-01-01

    Bone fragility is a silent condition that increases bone fracture risk, enhanced by low bone mass and microarchitecture deterioration of bone tissue that lead to osteoporosis. Fragility fractures are the major clinical manifestation of osteoporosis. A large body of epidemiological data indicates that the current standard for predicting fragility fracture risk is an areal BMD (aBMD) measurement by DXA. Although mineral density measurements assess the quantity of bone, the quality of the tissue is an important predictor of fragility. Thus, bone strength is explained not only by BMD but also by macrostructural and microstructural characteristics of bone tissue. Imaging diagnostics, through the use of X-rays, DXA, Ultrasonography, CT and MR, provides methods for diagnosis and characterization of fractures, and semi- and quantitative methods for assessment of bone consistency and strength, that become precious for bone fragility clinical management if they are integrated by clinical risk factors. The last employment of sophisticated non-invasively imaging techniques in clinical research as high-resolution CT (hrCT), microCT (μ-CT), high-resolution MR (hrMR) and, microRM (μRM), combined with finite element analysis methods, open to new challenges in a better bone strength assessment to enhance the comprehension of biomechanical parameters and the prediction of fragility fractures. PMID:22461252

  4. A comparison of optical and electromagnetic computer-assisted navigation systems for fluoroscopic targeting.

    PubMed

    Ricci, William M; Russell, Thomas A; Kahler, David M; Terrill-Grisoni, Lauralan; Culley, Patrick

    2008-03-01

    Freehand targeting using fluoroscopic guidance is routine for placement of interlocking screws associated with intramedullary nailing and for insertion of screws for reconstruction of pelvic and acetabular injuries. New technologies that use fluoroscopy with the assistance of computer guidance have the potential to improve accuracy and reduce radiation exposure to patient and surgeon. We sought to compare 2 fluoroscopic navigation tracking technologies, optical and electromagnetic versus standard freehand fluoroscopic targeting in a standardized model. Three experienced orthopaedic trauma surgeons placed 3.2-mm guide pins through test foam blocks that simulate cancellous bone. The entry site for each pin was within a circular (18-mm) entry zone. On the opposite surface of the test block (130-mm across), the target was a 1-mm-diameter radioopaque spherical ball marker. Each surgeon placed 10 pins using freehand targeting (control group) navigation using Medtronic iON StealthStation (Optical A), navigation using BrainLAB VectorVision (Optical B), or navigation using GE Medical Systems InstaTrak 3500 system (EM). Data were collected for accuracy (the distance from the exit site of the guidewire to the target spherical ball marker), fluoroscopy time (seconds), and total number of individual fluoroscopy images taken. The 2 optical systems and the electromagnetic system provided significantly improved accuracy compared to freehand technique. The average distance from the target was significantly (3.5 times) greater for controls (7.1 mm) than for each of the navigated systems (Optical A = 2.1 mm, Optical B = 1.9 mm EM = 2.4 mm; P < .05). Accuracy was similar for the 3 navigated systems, (P > 0.05). The ability to place guidewires in a 5-mm safe zone surrounding the target sphere was also significantly improved with the optical systems and the EM system (99% of wires in the safe zone) compared to controls (47% in the safe zone) (P < 0.002). Safe zone placement was similar

  5. Image Transmission via Spread Spectrum Techniques

    DTIC Science & Technology

    1978-01-01

    Images From Remote Piloted Vehicles, Coding Techniques For RPV and SAR Images, Image Coding Techniques, Stochastic Image Models and Hybrid Coding...FAST COSINE TRANSFORM. . . 125 APPENDIX E: STUDY OF HUMAN FACTORS INVOLVED WITH VIEWING COMPRESSED IMAGES FROM REMOTE PILOTED VEHICLES...Program was accomplished in 1977. A complete flyable system was produced by RCA and delivered to Harris Corp for integration into an AQUILA remotely

  6. Imaging Techniques in Endodontics: An Overview

    PubMed Central

    Deepak, B. S.; Subash, T. S.; Narmatha, V. J.; Anamika, T.; Snehil, T. K.; Nandini, D. B.

    2012-01-01

    This review provides an overview of the relevance of imaging techniques such as, computed tomography, cone beam computed tomography, and ultrasound, to endodontic practice. Many limitations of the conventional radiographic techniques have been overcome by the newer methods. Advantages and disadvantages of various imaging techniques in endodontic practice are also discussed. PMID:22530184

  7. Digital image registration by correlation techniques.

    NASA Technical Reports Server (NTRS)

    Popp, D. J.; Mccormack, D. S.; Lee, G. M.

    1972-01-01

    This study considers the translation problem associated with digital image registration and develops a means for comparing commonly used correlation techniques. Using suitably defined constraints, an optimum and four suboptimum registration techniques are defined and evaluated. A computational comparison is made and Gaussian image statistics are used to compare the selected techniques in terms of radial position location error.

  8. Access Techniques for Document Image Databases.

    ERIC Educational Resources Information Center

    Walker, Frank L.; Thoma, George R.

    1990-01-01

    Describes access and retrieval techniques implemented as part of a research and development program in electronic imaging applied to document storage and retrieval at the National Library of Medicine. Design considerations for large image databases are discussed. (six references) (EAM)

  9. Medical imaging techniques: implications for nursing care.

    PubMed

    Malcolm, Alison

    The four basic techniques of medical imaging are X-ray, ultrasound, magnetic resonance and radionuclide. This article describes imaging techniques that display anatomical structure and those that are better at showing the physiological function of organs and tissues. Safety and preparation relating to nursing practice are discussed. Understanding the purpose and limitations of the different imaging techniques is important for providing best patient care.

  10. Improved contrast and spatial resolution with Single Photon Counting (SPC) for an area x-ray imager, the newly developed high-resolution Micro-Angiographic Fluoroscopic (MAF) detector.

    PubMed

    Jain, Amit; Kuhls-Gilcrist, Andrew; Bednarek, Daniel R; Rudin, Stephen

    2009-12-31

    Although in radiological imaging, the prevailing mode of acquisition is the integration of the energy deposited by all x-rays absorbed in the imaging detector, much improvement in image spatial and contrast resolution could be achieved if each individual x-ray photon were detected and counted separately. In this work we compare the conventional energy integration (EI) mode with the new single photon counting (SPC) mode for a recently developed high-resolution Micro-Angiographic Fluoroscopic (MAF) detector, which is uniquely capable of both modes of operation. The MAF has 1024×1024 pixels of 35 microns effective size and is capable of real-time imaging at 30 fps. The large variable gain of its light image intensifier (LII) provides quantum limited operation with essentially no additive instrumentation noise and enables the MAF to operate in both EI and the very sensitive low-exposure SPC modes. We used high LII gain with very low exposure (<1 x-ray photon/pixel) per frame for SPC mode and higher exposure per frame with lower gain for EI mode. Multiple signal-thresholded frames were summed in SPC mode to provide an integrated frame with the same total exposure as EI mode. A heavily K-edge filtered x-ray beam (average energy of 31 keV) was used to provide a nearly monochromatic spectrum. The MTF measured using a standard slit method showed a dramatic improvement for the SPC mode over the EI mode at all frequencies. Images of a line pair phantom also showed improved spatial resolution with 12 lp/mm visible in SPC mode compared to only 8 lp/mm in EI mode. In SPC mode, images of human distal and middle phalanges showed the trabecular structures of the bone with far better contrast and detail. These improvements with the SPC mode should be advantageous for clinical applications where high resolution and/or high contrast are essential such as in mammography and extremity imaging as well as for dual modality applications, which combine nuclear medicine and x-ray imaging

  11. Interframe Adaptive Data Compression Techniques for Images.

    DTIC Science & Technology

    1979-08-01

    1.3.1 Predictive Coding Techniques 8 1.3.2 Transform Coding Techniques 15 1.3.3 Hybrid Coding Techniques 17 1.4 Research Objectives 18 1.5 Description ...Chemical Plant Images 82 4.2.3 X-ray Projection Images 83 V INTERFRAME HYBRID CODING SCHEMES 91 5.1 Adaptive Interframe Hybrid Coding Scheme 95 5.2 Hybrid...Images 99 5.4.2 Chemical Plant Images 109 5.4.3 Angiocardiogram Images .7 777 T- - . vi Page VI DATA COMPRESSION FOR NOISY CHANNELS 117 6.1 Channel

  12. The influence of injecting an epidural contrast agent into the sacral canal on the fluoroscopic visibility of bony landmarks for sacroiliac screw fixation: a feasibility study.

    PubMed

    Mendel, Thomas; Radetzki, Florian; Schwan, Stefan; Hofmann, Gunther Olaf; Goehre, Felix

    2015-02-01

    In sacroiliac screw fixation of unstable pelvic injuries in geriatric patients, poor bone quality often obscures important bony landmarks in fluoroscopic images. The authors analyzed the feasibility of injecting a transhiatal contrast agent (CA) into the sacral canal to improve fluoroscopic visualization in the sacral epidural space. Eight fresh cadaveric whole-body specimens from human donors whose mean age at the time of death was 78 years (range 69-87 years) were used. First, to identify bony landmarks without CA enhancement, the authors acquired fluoroscopy images of the native sacral canal, using lateral, inlet, and outlet projections. Through puncture of the sacral hiatus, 8-10 ml of CA was injected into the epidural space. Fluoroscopy images were then acquired in the standard pelvic views to identify the bony landmarks. To assess the effect of the CA enhancement, visibility of the landmarks was assessed before and after CA injection. Each identified landmark was scored as 1, and summative landmark scores of up to 10 were determined for each specimen. The cadaveric specimens were representative of bone structures in the geriatric population. In all specimens, epidural CA injection enhanced the fluoroscopic visualization of the sacral canal and of the S-1 foramina. The enhancement increased the total bony landmark score from 5.9 (range 4-8) without CA injection to 8.1 (range 6-10) after CA injection. Considering only intrasacral landmarks, the score was increased from 1.5 to 3. Injection of a transhiatal epidural CA improves fluoroscopic imaging of the sacral canal and of the neural foramina. Hence, this technique could be applied to help the surgeon identify anatomical landmarks during sacroiliac screw fixation in geriatric patients.

  13. The lixiscope: A portable X-ray fluoroscope

    NASA Astrophysics Data System (ADS)

    van Pelt, Bruce; Plevak, Joseph F.

    1986-01-01

    The lixi imaging scope is a portable fluoroscope which is a substantial improvement over the original concept and prototype of the lixiscope invented by NASA . This device has found widespread use in industrial, medical and security screening applications. Users of it have found its small size and high quality real-time image to provide early detection of defects in some cases, save time and money in others, and reduce patient dose and inconvenience in still others. NASA patent 4, 142, 101 July, 1977, Lo I Yin, Lixi, Inc. is the exclusive Licensee of the radioisotope version of the lixiscope.

  14. Psychophysical rating of image compression techniques

    NASA Technical Reports Server (NTRS)

    Stein, Charles S.; Hitchner, Lewis E.; Watson, Andrew B.

    1989-01-01

    Image compression schemes abound with little work which compares their bit-rate performance based on subjective fidelity measures. Statistical measures of image fidelity, such as squared error measures, do not necessarily correspond to subjective measures of image fidelity. Most previous comparisons of compression techniques have been based on these statistical measures. A psychophysical method has been used to estimate, for a number of compression techniques, a threshold bit-rate yielding a criterion level of performance in discriminating original and compressed images. The compression techniques studied include block truncation, Laplacian pyramid, block discrete cosine transform, with and without a human visual system scaling, and cortex transform coders.

  15. Psychophysical rating of image compression techniques

    NASA Technical Reports Server (NTRS)

    Stein, Charles S.; Hitchner, Lewis E.; Watson, Andrew B.

    1989-01-01

    Image compression schemes abound with little work which compares their bit-rate performance based on subjective fidelity measures. Statistical measures of image fidelity, such as squared error measures, do not necessarily correspond to subjective measures of image fidelity. Most previous comparisons of compression techniques have been based on these statistical measures. A psychophysical method has been used to estimate, for a number of compression techniques, a threshold bit-rate yielding a criterion level of performance in discriminating original and compressed images. The compression techniques studied include block truncation, Laplacian pyramid, block discrete cosine transform, with and without a human visual system scaling, and cortex transform coders.

  16. NMR imaging techniques and applications: A review

    NASA Astrophysics Data System (ADS)

    Bottomley, Paul A.

    1982-09-01

    Over the past ten years, a variety of techniques have been proposed and demonstrated that enable the spatial discrimination and mapping of nuclear-magnetic-resonance (NMR) signals in heterogeneous objects. These NMR imaging techniques are currently finding useful application in clinical medicine and physiological chemistry, where their noninvasive, apparently hazard-free nature, and the sensitivity of the NMR signal to the state of biological tissue, are key advantages. This article reviews the historical development, the conceptual basis, and the applications of the various NMR imaging techniques. Qualitative descriptions and illustrations of each technique and an outline of imaging instrumentation are provided. Proton NMR imaging, in medicine, of pathological states such as cancer, imaging of relaxation time, chemical shift and flow parameters, imaging of nuclei other than hydrogen, and potential hazards are discussed and demonstrated with examples.

  17. Three dimensional scattering center imaging techniques

    NASA Technical Reports Server (NTRS)

    Younger, P. R.; Burnside, W. D.

    1991-01-01

    Two methods to image scattering centers in 3-D are presented. The first method uses 2-D images generated from Inverse Synthetic Aperture Radar (ISAR) measurements taken by two vertically offset antennas. This technique is shown to provide accurate 3-D imaging capability which can be added to an existing ISAR measurement system, requiring only the addition of a second antenna. The second technique uses target impulse responses generated from wideband radar measurements from three slightly different offset antennas. This technique is shown to identify the dominant scattering centers on a target in nearly real time. The number of measurements required to image a target using this technique is very small relative to traditional imaging techniques.

  18. Imaging techniques: Nanoparticle atoms pinpointed

    NASA Astrophysics Data System (ADS)

    Farle, Michael

    2017-02-01

    The locations of atoms in a metallic alloy nanoparticle have been determined using a combination of electron microscopy and image simulation, revealing links between the particle's structure and magnetic properties. See Letter p.75

  19. Ultra high speed image processing techniques. [electronic packaging techniques

    NASA Technical Reports Server (NTRS)

    Anthony, T.; Hoeschele, D. F.; Connery, R.; Ehland, J.; Billings, J.

    1981-01-01

    Packaging techniques for ultra high speed image processing were developed. These techniques involve the development of a signal feedthrough technique through LSI/VLSI sapphire substrates. This allows the stacking of LSI/VLSI circuit substrates in a 3 dimensional package with greatly reduced length of interconnecting lines between the LSI/VLSI circuits. The reduced parasitic capacitances results in higher LSI/VLSI computational speeds at significantly reduced power consumption levels.

  20. Electronic imaging system and technique

    DOEpatents

    Bolstad, Jon O.

    1987-01-01

    A method and system for viewing objects obscurred by intense plasmas or flames (such as a welding arc) includes a pulsed light source to illuminate the object, the peak brightness of the light reflected from the object being greater than the brightness of the intense plasma or flame; an electronic image sensor for detecting a pulsed image of the illuminated object, the sensor being operated as a high-speed shutter; and electronic means for synchronizing the shutter operation with the pulsed light source.

  1. Electronic imaging system and technique

    DOEpatents

    Bolstad, J.O.

    1984-06-12

    A method and system for viewing objects obscurred by intense plasmas or flames (such as a welding arc) includes a pulsed light source to illuminate the object, the peak brightness of the light reflected from the object being greater than the brightness of the intense plasma or flame; an electronic image sensor for detecting a pulsed image of the illuminated object, the sensor being operated as a high-speed shutter; and electronic means for synchronizing the shutter operation with the pulsed light source.

  2. An accurate registration technique for distorted images

    NASA Technical Reports Server (NTRS)

    Delapena, Michele; Shaw, Richard A.; Linde, Peter; Dravins, Dainis

    1990-01-01

    Accurate registration of International Ultraviolet Explorer (IUE) images is crucial because the variability of the geometrical distortions that are introduced by the SEC-Vidicon cameras ensures that raw science images are never perfectly aligned with the Intensity Transfer Functions (ITFs) (i.e., graded floodlamp exposures that are used to linearize and normalize the camera response). A technique for precisely registering IUE images which uses a cross correlation of the fixed pattern that exists in all raw IUE images is described.

  3. Google Glass as an Alternative to Standard Fluoroscopic Visualization for Percutaneous Fixation of Hand Fractures: A Pilot Study.

    PubMed

    Chimenti, Peter C; Mitten, David J

    2015-08-01

    This pilot study investigated the feasibility of Google Glass to assist visualization of fluoroscopic images during percutaneous pinning of hand fractures. Cadavers were used to compare total time to pin each fracture and total number of radiographs per fracture from a mini C-arm. A FluoroScan monitor was used for radiographic visualization compared to projecting the images in the Google Glass display. All outcome measures significantly improved for proximal phalanx fractures (127 versus 86 seconds, p = 0.017; 5.3 versus 2.2 images, p = 0.003), and fewer images were obtained during fixation of metacarpal fractures using Google Glass compared with traditional techniques (6.4 versus 3.6, p < 0.001). Typical FluoroScan monitor placement may require the surgeon to alter focus away from the operative field, whereas Google Glass allows constant attention directed toward the operative field.

  4. Image processing technique for arbitrary image positioning in holographic stereogram

    NASA Astrophysics Data System (ADS)

    Kang, Der-Kuan; Yamaguchi, Masahiro; Honda, Toshio; Ohyama, Nagaaki

    1990-12-01

    In a one-step holographic stereogram, if the series of original images are used just as they are taken from perspective views, three-dimensional images are usually reconstructed in back of the hologram plane. In order to enhance the sense of perspective of the reconstructed images and minimize blur of the interesting portions, we introduce an image processing technique for making a one-step flat format holographic stereogram in which three-dimensional images can be observed at an arbitrary specified position. Experimental results show the effect of the image processing. Further, we show results of a medical application using this image processing.

  5. Improvement of ultrasound speckle image velocimetry using image enhancement techniques.

    PubMed

    Yeom, Eunseop; Nam, Kweon-Ho; Paeng, Dong-Guk; Lee, Sang Joon

    2014-01-01

    Ultrasound-based techniques have been developed and widely used in noninvasive measurement of blood velocity. Speckle image velocimetry (SIV), which applies a cross-correlation algorithm to consecutive B-mode images of blood flow has often been employed owing to its better spatial resolution compared with conventional Doppler-based measurement techniques. The SIV technique utilizes speckles backscattered from red blood cell (RBC) aggregates as flow tracers. Hence, the intensity and size of such speckles are highly dependent on hemodynamic conditions. The grayscale intensity of speckle images varies along the radial direction of blood vessels because of the shear rate dependence of RBC aggregation. This inhomogeneous distribution of echo speckles decreases the signal-to-noise ratio (SNR) of a cross-correlation analysis and produces spurious results. In the present study, image-enhancement techniques such as contrast-limited adaptive histogram equalization (CLAHE), min/max technique, and subtraction of background image (SB) method were applied to speckle images to achieve a more accurate SIV measurement. A mechanical sector ultrasound scanner was used to obtain ultrasound speckle images from rat blood under steady and pulsatile flows. The effects of the image-enhancement techniques on SIV analysis were evaluated by comparing image intensities, velocities, and cross-correlation maps. The velocity profiles and wall shear rate (WSR) obtained from RBC suspension images were compared with the analytical solution for validation. In addition, the image-enhancement techniques were applied to in vivo measurement of blood flow in human vein. The experimental results of both in vitro and in vivo SIV measurements show that the intensity gradient in heterogeneous speckles has substantial influence on the cross-correlation analysis. The image-enhancement techniques used in this study can minimize errors encountered in ultrasound SIV measurement in which RBCs are used as flow

  6. Plenoptic Ophthalmoscopy: A Novel Imaging Technique.

    PubMed

    Adam, Murtaza K; Aenchbacher, Weston; Kurzweg, Timothy; Hsu, Jason

    2016-11-01

    This prospective retinal imaging case series was designed to establish feasibility of plenoptic ophthalmoscopy (PO), a novel mydriatic fundus imaging technique. A custom variable intensity LED array light source adapter was created for the Lytro Gen1 light-field camera (Lytro, Mountain View, CA). Initial PO testing was performed on a model eye and rabbit fundi. PO image acquisition was then performed on dilated human subjects with a variety of retinal pathology and images were subjected to computational enhancement. The Lytro Gen1 light-field camera with custom LED array captured fundus images of eyes with diabetic retinopathy, age-related macular degeneration, retinal detachment, and other diagnoses. Post-acquisition computational processing allowed for refocusing and perspective shifting of retinal PO images, resulting in improved image quality. The application of PO to image the ocular fundus is feasible. Additional studies are needed to determine its potential clinical utility. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:1038-1043.].

  7. FPGA implementation of image enhancement techniques

    NASA Astrophysics Data System (ADS)

    Kumar, Karan; Jain, Aditya; Srivastava, Atul Kumar

    2009-06-01

    The objective of this paper is designing, modeling, simulation and synthesis of four Image Enhancement techniques on FPGA. Image Enhancement Algorithms can be classified as point processing Techniques, in which operation is done on pixel level and Spatial Filtering Technique, in which operation is performed within neighborhood of a pixel. Algorithms of all the techniques are studied and hardware circuits are realized for them. Then hardware logic is modeled in Matlab Simulink using Xilinx System Generator Block set and synthesized onto Virtex4 xc4vsx35-10ff668 FPGA chip. Using hardware co-simulation feature of FPGA kit, the algorithms developed are validated.

  8. CT fluoroscopic guided insertion of inferior vena cava filters.

    PubMed

    Ignotus, P; Wetton, C; Berry, J

    2006-03-01

    The value and use of inferior vena cava (IVC) filters is well documented and has been growing since the first reported filter placement in 1973 and the first percutaneous insertion in 1982. Access routes now include both jugular veins, both ante-cubital veins and both femoral veins. However, all insertions require some form of imaging, usually fluoroscopy, to identify the location of the filter with respect to the IVC and the renal veins. We describe two cases where the patients' weight was significantly greater than the weight limit of the angiography table, necessitating insertion under CT fluoroscopic guidance.

  9. A comparison of image inpainting techniques

    NASA Astrophysics Data System (ADS)

    Liu, Yaojie; Shu, Chang

    2015-03-01

    Image inpainting is an important research topic in the field of image processing. The objective of inpainting is to "guess" the lost information according to surrounding image information, which can be applied in old photo restoration, object removal and demosaicing. Based on the foundation of previous literature of image inpainting and image modeling, this paper provides an overview of the state-of-art image inpainting methods. This survey first covers mathematics models of inpainting and different kinds of image impairment. Then it goes to the main components of an image, the structure and the texture, and states how these inpainting models and algorithms deal with the two separately, using PDE's method, exemplar-based method and etc. Afterwards sparse-representation-based inpainting and related techniques are introduced. Experimental analysis will be presented to evaluate the relative merits of different algorithms, with the measure of Peak Signal to Noise Ratio (PSNR) as well as direct visual perception.

  10. Enhanced integral imaging system using image floating technique

    NASA Astrophysics Data System (ADS)

    Min, Sung-Wook; Kim, Joohwan; Lee, Byoungho

    2005-09-01

    Enhanced integral imaging system based on the image floating method is proposed. The integral imaging is one of the most promising methods among the autostereoscopic displays and the integrated image has the volumetric characteristics unlike the other stereoscopic images. The image floating is a common 3D display technique, which uses a big convex lens or a concave mirror to exhibit the image of a real object to the observer. The image floating method can be used to emphasize the viewing characteristics of the volumetric image and the noise image which is located on the fixed plane can be eliminated by the floating lens through the control of the focal length. In this paper, the solution of the seam noise and the image flipping of the integral imaging system is proposed using the image floating method. Moreover, the advanced techniques of the integral imaging system can be directly applied to the proposed system. The proposed system can be successfully applied to many 3D applications such as 3D television.

  11. Image processing techniques for digital orthophotoquad production

    USGS Publications Warehouse

    Hood, Joy J.; Ladner, L. J.; Champion, Richard A.

    1989-01-01

    Orthophotographs have long been recognized for their value as supplements or alternatives to standard maps. Recent trends towards digital cartography have resulted in efforts by the US Geological Survey to develop a digital orthophotoquad production system. Digital image files were created by scanning color infrared photographs on a microdensitometer. Rectification techniques were applied to remove tile and relief displacement, thereby creating digital orthophotos. Image mosaicking software was then used to join the rectified images, producing digital orthophotos in quadrangle format.

  12. Superresolution imaging: a survey of current techniques

    NASA Astrophysics Data System (ADS)

    Cristóbal, G.; Gil, E.; Šroubek, F.; Flusser, J.; Miravet, C.; Rodríguez, F. B.

    2008-08-01

    Imaging plays a key role in many diverse areas of application, such as astronomy, remote sensing, microscopy, and tomography. Owing to imperfections of measuring devices (e.g., optical degradations, limited size of sensors) and instability of the observed scene (e.g., object motion, media turbulence), acquired images can be indistinct, noisy, and may exhibit insuffcient spatial and temporal resolution. In particular, several external effects blur images. Techniques for recovering the original image include blind deconvolution (to remove blur) and superresolution (SR). The stability of these methods depends on having more than one image of the same frame. Differences between images are necessary to provide new information, but they can be almost unperceivable. State-of-the-art SR techniques achieve remarkable results in resolution enhancement by estimating the subpixel shifts between images, but they lack any apparatus for calculating the blurs. In this paper, after introducing a review of current SR techniques we describe two recently developed SR methods by the authors. First, we introduce a variational method that minimizes a regularized energy function with respect to the high resolution image and blurs. In this way we establish a unifying way to simultaneously estimate the blurs and the high resolution image. By estimating blurs we automatically estimate shifts with subpixel accuracy, which is inherent for good SR performance. Second, an innovative learning-based algorithm using a neural architecture for SR is described. Comparative experiments on real data illustrate the robustness and utilization of both methods.

  13. Three-dimensional curvilinear device reconstruction from two fluoroscopic views

    NASA Astrophysics Data System (ADS)

    Delmas, Charlotte; Berger, Marie-Odile; Kerrien, Erwan; Riddell, Cyril; Trousset, Yves; Anxionnat, René; Bracard, Serge

    2015-03-01

    In interventional radiology, navigating devices under the sole guidance of fluoroscopic images inside a complex architecture of tortuous and narrow vessels like the cerebral vascular tree is a difficult task. Visualizing the device in 3D could facilitate this navigation. For curvilinear devices such as guide-wires and catheters, a 3D reconstruction may be achieved using two simultaneous fluoroscopic views, as available on a biplane acquisition system. The purpose of this paper is to present a new automatic three-dimensional curve reconstruction method that has the potential to reconstruct complex 3D curves and does not require a perfect segmentation of the endovascular device. Using epipolar geometry, our algorithm translates the point correspondence problem into a segment correspondence problem. Candidate 3D curves can be formed and evaluated independently after identifying all possible combinations of compatible 3D segments. Correspondence is then inherently solved by looking in 3D space for the most coherent curve in terms of continuity and curvature. This problem can be cast into a graph problem where the most coherent curve corresponds to the shortest path of a weighted graph. We present quantitative results of curve reconstructions performed from numerically simulated projections of tortuous 3D curves extracted from cerebral vascular trees affected with brain arteriovenous malformations as well as fluoroscopic image pairs of a guide-wire from both phantom and clinical sets. Our method was able to select the correct 3D segments in 97.5% of simulated cases thus demonstrating its ability to handle complex 3D curves and can deal with imperfect 2D segmentation.

  14. Reduction in average fluoroscopic exposure times for interventional spinal procedures through the use of pulsed and low-dose image settings.

    PubMed

    Goodman, Bradly S; Carnel, Charles T; Mallempati, Srinivas; Agarwal, Pooja

    2011-11-01

    A practice improvement project was completed with the goal of reducing radiation exposure times in a busy spinal intervention practice through the use of "pulsed" and "low-dose fluoroscopy." The goal was to quantify the reduction in fluoroscopy exposure times with these modes. Exposure times were recorded for 316 patients undergoing spinal interventional procedures before and after the implementation of this project. Before implementation, 158 consecutive patients received spinal interventions with nonpulsed fluoroscopy on an Orthopedic Equipment Company 9800 and exposure times were recorded. After implementation of the practice improvement project, 158 consecutive patients received spinal interventions with pulsed and low-dose modes. Exposure times were then compared between these groups. Pulsed and low-dose fluoroscopy modes reduced overall exposure times by 56.7% after implementation of the practice improvement project. The use of pulsed and low-dose fluoroscopy in addition to lead shielding; increasing distance from the radiation source; collimation; limited use of magnification, boost, or digital subtraction; and proficiency with interventional techniques should be used to reduce radiation exposure in concordance with the principle of "as low as reasonably achievable."

  15. Image registration techniques for multimodal sensors

    NASA Astrophysics Data System (ADS)

    Altinalev, Tevfik; Cetin, Enis A.; Yardimci, Yasemin C.

    2002-08-01

    Image registration refers to the problem of spatially aligning two or more images. A challenging problem in this area is the registration of images obtained by different types of sensors. In general such images have different gray level characteristics and commonly used techniques such as those based on area correlations cannot be applied directly. On the other hand, contours representing the region boundaries are preserved in most cases. Therefore, contour based registration techniques are applicable to multimodal sensors. In this paper, various registration techniques based on subband decomposition and projection along x and y directions are introduced. The effect of binarization is investigated. Unknown translation and scaling parameters are computed using cross-correlation methods over the projections. Performance of the algorithms is compared.

  16. Ultrasonic imaging techniques for breast cancer detection.

    SciTech Connect

    Goulding, N. R.; Marquez, J. D.; Prewett, E. M.; Claytor, T. N.; Nadler, B. R.; Huang, L.

    2006-01-01

    Improving the resolution and specificity of current ultrasonic imaging technology can enhance its relevance to detection of early-stage breast cancers. Ultrasonic evaluation of breast lesions is desirable because it is quick, inexpensive, and does not expose the patient to potentially harmful ionizing radiation. Improved image quality and resolution enables earlier detection and more accurate diagnoses of tumors, thus reducing the number of biopsies performed, increasing treatment options, and lowering mortality, morbidity, and remission percentages. In this work, a novel ultrasonic imaging reconstruction method that exploits straight-ray migration is described. This technique, commonly used in seismic imaging, accounts for scattering more accurately than standard ultrasonic approaches, thus providing superior image resolution. A breast phantom with various inclusions is imaged using a pulse-echo approach. The data are processed using the ultrasonic migration method and results are compared to standard linear ultrasound and to x-ray computed tomography (CT) scans. For an ultrasonic frequency of 2.25 MHz, imaged inclusions and features of approximately 1mm are resolved, although better resolution is expected with minor modifications. Refinement of this application using other imaging techniques such as time-reversal mirrors (TRM), synthetic aperture focusing technique (SAFT), decomposition of the time reversal operator (DORT), and factorization methods is also briefly discussed.

  17. Ultrasonic Imaging Techniques for Breast Cancer Detection

    NASA Astrophysics Data System (ADS)

    Goulding, N. R.; Marquez, J. D.; Prewett, E. M.; Claytor, T. N.; Nadler, B. R.

    2008-02-01

    Improving the resolution and specificity of current ultrasonic imaging technology is needed to enhance its relevance to breast cancer detection. A novel ultrasonic imaging reconstruction method is described that exploits classical straight-ray migration. This novel method improves signal processing for better image resolution and uses novel staging hardware options using a pulse-echo approach. A breast phantom with various inclusions is imaged using the classical migration method and is compared to standard computed tomography (CT) scans. These innovative ultrasonic methods incorporate ultrasound data acquisition, beam profile characterization, and image reconstruction. For an ultrasonic frequency of 2.25 MHz, imaged inclusions of approximately 1 cm are resolved and identified. Better resolution is expected with minor modifications. Improved image quality and resolution enables earlier detection and more accurate diagnoses of tumors thus reducing the number of biopsies performed, increasing treatment options, and lowering remission percentages. Using these new techniques the inclusions in the phantom are resolved and compared to the results of standard methods. Refinement of this application using other imaging techniques such as time-reversal mirrors (TRM), synthetic aperture focusing technique (SAFT), decomposition of the time reversal operator (DORT), and factorization methods is also discussed.

  18. A low-cost, durable, combined ultrasound and fluoroscopic phantom for cervical transforaminal injections.

    PubMed

    Lerman, Imanuel R; Souzdalnitski, Dmitri; Narouze, Samer

    2012-01-01

    This technical report describes a durable, low-cost, anatomically accurate, and easy-to-prepare combined ultrasound (US) and fluoroscopic phantom of the cervical spine. This phantom is meant to augment training in US- and fluoroscopic-guided pain medicine procedures. The combined US and fluoroscopic phantom (CUF-P) is prepared from commercially available liquid plastic that is ordinarily used to prepare synthetic fishing lures. The liquid plastic is heated and then poured into a metal canister that houses an anatomical cervical spine model. Drops of dark purple dye are added to make the phantom opaque. After cooling, tubing is attached to the CUF-P to simulate blood vessels. The CUF-P accurately simulates human tissue by imitating both the tactile texture of skin and the haptic resistance of human tissue as the needle is advanced. This phantom contains simulated fluid-filled vertebral arteries that exhibit pulsed flow under color Doppler US. Under fluoroscopic examination, the CUF-P-simulated vertebral arteries also exhibit uptake of contrast dye if mistakenly injected. The creation of a training phantom allows the pain physician to practice needle positioning technique while simultaneously visualizing both targeted and avoidable vascular structures under US and fluoroscopic guidance. This low-cost CUF-P is easy to prepare and is reusable, making it an attractive alternative to current homemade and commercially available phantom simulators.

  19. Robust document image binarization technique for degraded document images.

    PubMed

    Su, Bolan; Lu, Shijian; Tan, Chew Lim

    2013-04-01

    Segmentation of text from badly degraded document images is a very challenging task due to the high inter/intra-variation between the document background and the foreground text of different document images. In this paper, we propose a novel document image binarization technique that addresses these issues by using adaptive image contrast. The adaptive image contrast is a combination of the local image contrast and the local image gradient that is tolerant to text and background variation caused by different types of document degradations. In the proposed technique, an adaptive contrast map is first constructed for an input degraded document image. The contrast map is then binarized and combined with Canny's edge map to identify the text stroke edge pixels. The document text is further segmented by a local threshold that is estimated based on the intensities of detected text stroke edge pixels within a local window. The proposed method is simple, robust, and involves minimum parameter tuning. It has been tested on three public datasets that are used in the recent document image binarization contest (DIBCO) 2009 & 2011 and handwritten-DIBCO 2010 and achieves accuracies of 93.5%, 87.8%, and 92.03%, respectively, that are significantly higher than or close to that of the best-performing methods reported in the three contests. Experiments on the Bickley diary dataset that consists of several challenging bad quality document images also show the superior performance of our proposed method, compared with other techniques.

  20. Review: Magnetic resonance imaging techniques in ophthalmology

    PubMed Central

    Fagan, Andrew J.

    2012-01-01

    Imaging the eye with magnetic resonance imaging (MRI) has proved difficult due to the eye’s propensity to move involuntarily over typical imaging timescales, obscuring the fine structure in the eye due to the resulting motion artifacts. However, advances in MRI technology help to mitigate such drawbacks, enabling the acquisition of high spatiotemporal resolution images with a variety of contrast mechanisms. This review aims to classify the MRI techniques used to date in clinical and preclinical ophthalmologic studies, describing the qualitative and quantitative information that may be extracted and how this may inform on ocular pathophysiology. PMID:23112569

  1. Techniques for molecular imaging probe design.

    PubMed

    Reynolds, Fred; Kelly, Kimberly A

    2011-12-01

    Molecular imaging allows clinicians to visualize disease-specific molecules, thereby providing relevant information in the diagnosis and treatment of patients. With advances in genomics and proteomics and underlying mechanisms of disease pathology, the number of targets identified has significantly outpaced the number of developed molecular imaging probes. There has been a concerted effort to bridge this gap with multidisciplinary efforts in chemistry, proteomics, physics, material science, and biology--all essential to progress in molecular imaging probe development. In this review, we discuss target selection, screening techniques, and probe optimization with the aim of developing clinically relevant molecularly targeted imaging agents.

  2. Techniques for Molecular Imaging Probe Design

    PubMed Central

    Reynolds, Fred; Kelly, Kimberly A.

    2011-01-01

    Molecular imaging allows clinicians to visualize disease specific molecules, thereby providing relevant information in the diagnosis and treatment of patients. With advances in genomics and proteomics and underlying mechanisms of disease pathology, the number of targets identified has significantly outpaced the number of developed molecular imaging probes. There has been a concerted effort to bridge this gap with multidisciplinary efforts in chemistry, proteomics, physics, material science, and biology; all essential to progress in molecular imaging probe development. In this review, we will discuss target selection, screening techniques and probe optimization with the aim of developing clinically relevant molecularly targeted imaging agents. PMID:22201532

  3. Geometric assessment of image quality using digital image registration techniques

    NASA Technical Reports Server (NTRS)

    Tisdale, G. E.

    1976-01-01

    Image registration techniques were developed to perform a geometric quality assessment of multispectral and multitemporal image pairs. Based upon LANDSAT tapes, accuracies to a small fraction of a pixel were demonstrated. Because it is insensitive to the choice of registration areas, the technique is well suited to performance in an automatic system. It may be implemented at megapixel-per-second rates using a commercial minicomputer in combination with a special purpose digital preprocessor.

  4. Feasibility and safety of infracolic fluoroscopically guided percutaneous radiologic gastrostomy.

    PubMed

    Cantwell, Colin P; Gervais, Debra A; Hahn, Peter F; Mueller, Peter R

    2008-01-01

    We study the feasibility and safety of infracolic fluoroscopically guided percutaneous gastrostomy when patient anatomy prevents conventional supracolic puncture. From September 2004 to April 2007, 508 gastrostomy and gastrojejunostomy catheters were inserted in a single institution, and in six patients, the position of the transverse colon prevented conventional supracolic puncture. All were male, with a mean age of 57 years. Four patients had head and neck cancer and two had neurologic conditions. With fluoroscopic guidance, a 14-F gastrostomy tube was inserted with T-fastener gastropexy caudal to the colon. The medical records of patients treated with this technique were reviewed for demographics, indication, technique, complications, function of gastrostomy, timing of removal of the gastrostomy, and subsequent hospital admissions. All procedures were technically successful and there was no procedure-related morbidity or mortality. The mean follow-up was 16 months (range, 7-25 months) and the mean duration of therapy was 7 months. Five patients had their gastrostomy removed after clinical improvement and one of these patients had a gastrostomy reinserted cephalic to the colon after recurrence of head and neck cancer. Two patients died of disease progression and one still had the gastrostomy in position. No patient was subsequently admitted for a complication of the technique or catheter malfunction. In conclusion, infracolic percutaneous radiologic gastrostomy with gastropexy is feasible in patients without an access route cephalic to the transverse colon.

  5. Occupational exposure from common fluoroscopic projections used in orthopaedic surgery.

    PubMed

    Theocharopoulos, Nicholas; Perisinakis, Kostas; Damilakis, John; Papadokostakis, George; Hadjipavlou, Alexander; Gourtsoyiannis, Nicholas

    2003-09-01

    Personnel assisting in or performing fluoroscopically guided procedures may be exposed to high doses of radiation. Accurate occupational dosimetric data for the orthopaedic theater staff are of paramount importance for practicing radiation safety. Fluoroscopic screening was performed on an anthropomorphic phantom with use of four projections common in image-guided orthopaedic surgery. The simulated projections were categorized, according to the imaged anatomic area and the beam orientation, as (1) hip joint posterior-anterior, (2) hip joint lateral cross-table 45 degrees, (3) lumbar spine anterior-posterior, and (4) lumbar spine lateral 90 degrees. The scattered air kerma rate was measured on a grid surrounding the operating table. For each grid point, the effective dose, eye lens dose, and face skin dose values, normalized over the tube dose area product, were derived. For the effective dose calculations, three radiation protection conditions were considered: (1) with the exposed personnel using no protection measures, (2) with the exposed personnel wearing a 0.5-mm lead-equivalent protective apron, and (3) with the exposed personnel wearing both an apron and a thyroid collar. Maximum permissible workloads for typical hip, spine, and kyphoplasty procedures were derived on the basis of compliance with effective dose, eye lens dose, and skin dose limits. We found that the effective dose, eye lens dose, and face skin dose to an orthopaedic surgeon wearing a 0.5-mm lead-equivalent apron will not exceed the corresponding limits if the dose area product of the fluoroscopically guided procedure is <0.38 Gy m (2). When protective eye goggles are also worn, the maximum permissible dose area product increases to 0.70 Gy m (2), while the additional use of a thyroid shield allows a workload of 1.20 Gy m (2). The effective dose to the orthopaedic surgeon working tableside during a typical hip, spine, kyphoplasty procedure was 5.1, 21, and 250 micro Sv, respectively, when a 0

  6. 21 CFR 1020.32 - Fluoroscopic equipment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... Radiation therapy simulation systems shall be exempt from this requirement provided the systems are intended... 10, 2006, other than radiation therapy simulation systems, the following applies: (A) Neither the... fluoroscopic equipment manufactured on or after June 10, 2006, other than radiation therapy simulation systems...

  7. 21 CFR 1020.32 - Fluoroscopic equipment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .... Radiation therapy simulation systems shall be exempt from this requirement provided the systems are intended... 10, 2006, other than radiation therapy simulation systems, the following applies: (A) Neither the... fluoroscopic equipment manufactured on or after June 10, 2006, other than radiation therapy simulation systems...

  8. New Jersey's Thomas Edison and the fluoroscope.

    PubMed

    Tselos, G D

    1995-11-01

    Thomas Edison played a major role in the development of early x-ray technology in 1896, notably increasing tube power and reliability and making the fluoroscope a practical instrument. Eventually, Edison would move x-ray technology from the laboratory to the marketplace.

  9. Comparison of various enhanced radar imaging techniques

    NASA Astrophysics Data System (ADS)

    Gupta, Inder J.; Gandhe, Avinash

    1998-09-01

    Recently, many techniques have been proposed to enhance the quality of radar images obtained using SAR and/or ISAR. These techniques include spatially variant apodization (SVA), adaptive sidelobe reduction (ASR), the Capon method, amplitude and phase estimation of sinusoids (APES) and data extrapolation. SVA is a special case of ASR; whereas the APES algorithm is similar to the Capon method except that it provides a better amplitude estimate. In this paper, the ASR technique, the APES algorithm and data extrapolation are used to generate radar images of two experimental targets and an airborne target. It is shown that although for ideal situations (point targets) the APES algorithm provides the best radar images (reduced sidelobe level and sharp main lobe), its performance degrades quickly for real world targets. The ASR algorithm gives radar images with low sidelobes but at the cost of some loss of information about the target. Also, there is not much improvement in radar image resolution. Data extrapolation, on the other hand, improves image resolution. In this case one can reduce the sidelobes by using non-uniform weights. Any loss in the radar image resolution due to non-uniform weights can be compensated by further extrapolating the scattered field data.

  10. Update on imaging techniques in oculoplastics

    PubMed Central

    Cetinkaya, Altug

    2012-01-01

    Imaging is a beneficial aid to the oculoplastic surgeon especially in orbital and lacrimal disorders when the pathology is not visible from outside. It is a powerful tool that may be benefited in not only diagnosis but also management and follow-up. The most common imaging modalities required are CT and MRI, with CT being more frequently ordered by oculoplastic surgeons. Improvements in technology enabled the acquisition times to shorten incredibly. Radiologists can now obtain images with superb resolution, and isolate the site and tissue of interest from other structures with special techniques. Better contrast agents and 3D imaging capabilities make complicated cases easier to identify. Color Doppler imaging is becoming more popular both for research and clinical purposes. Magnetic resonance angiography (MRA) added so much to the vascular system imaging recently. Although angiography is still the gold standard, new software and techniques rendered MRA as valuable as angiography in most circumstances. Stereotactic navigation, although in use for a long time, recently became the focus of interest for the oculoplastic surgeon especially in orbital decompressions. Improvements in radiology and nuclear medicine techniques of lacrimal drainage system imaging provided more detailed analysis of the system. PMID:23961020

  11. Interpretation techniques. [image enhancement and pattern recognition

    NASA Technical Reports Server (NTRS)

    Dragg, J. L.

    1974-01-01

    The image enhancement and geometric correction and registration techniques developed and/or demonstrated on ERTS data are relatively mature and greatly enhance the utility of the data for a large variety of users. Pattern recognition was improved by the use of signature extension, feature extension, and other classification techniques. Many of these techniques need to be developed and generalized to become operationally useful. Advancements in the mass precision processing of ERTS were demonstrated, providing the hope for future earth resources data to be provided in a more readily usable state. Also in evidence is an increasing and healthy interaction between the techniques developers and the user/applications investigators.

  12. Interpretation techniques. [image enhancement and pattern recognition

    NASA Technical Reports Server (NTRS)

    Dragg, J. L.

    1974-01-01

    The image enhancement and geometric correction and registration techniques developed and/or demonstrated on ERTS data are relatively mature and greatly enhance the utility of the data for a large variety of users. Pattern recognition was improved by the use of signature extension, feature extension, and other classification techniques. Many of these techniques need to be developed and generalized to become operationally useful. Advancements in the mass precision processing of ERTS were demonstrated, providing the hope for future earth resources data to be provided in a more readily usable state. Also in evidence is an increasing and healthy interaction between the techniques developers and the user/applications investigators.

  13. Investigating CBIR Techniques for Cervicographic Images

    PubMed Central

    Xue, Zhiyun; Antani, Sameer; Long, L. Rodney; Jeronimo, Jose; Thoma, George R.

    2007-01-01

    The National Library of Medicine (NLM) and the National Cancer Institute (NCI) are creating a digital archive of 100,000 cervicographic images and clinical and diagnostic data obtained through two major longitudinal studies. In addition to developing tools for Web access to these data, we are conducting research in Content-Based Image Retrieval (CBIR) techniques for retrieving visually similar and pathologically relevant images. The resulting system of tools is expected to greatly benefit medical education and research into uterine cervical cancer which is the second most common cancer affecting women worldwide. Our current prototype system with fundamental CBIR functions operates on a small test subset of images and retrieves relevant cervix images containing tissue regions similar in color, texture, size, and/or location to a query image region marked by the user. Initial average precision result for retrieval by color of acetowhite lesions is 52%, and for the columnar epithelium is 64.2%, respectively. PMID:18693952

  14. Digital Imaging Techniques for Radiotherapy Treatment Verification

    NASA Astrophysics Data System (ADS)

    Leszczynski, Konrad Wojciech

    The curative effect of ionizing radiation depends strongly upon the precision with which dose is delivered to the prescribed target volume. The requirement for high geometric accuracy in patient positioning is even more stringent where complex treatment techniques are used, such as conformal, dynamic arc or truly 3-D (non-coplanar) beams. It is expected that digital on-line portal imaging devices will play a key role in the monitoring of radiation therapy treatments. Different approaches to on-line portal image acquisition have been compared, and the basic imaging properties of a video portal imager have been evaluated and discussed in this thesis. Analysis of the system performance indicates the most efficient ways to effect improvements in spatial resolution and signal-to-noise ratio. Digital image processing techniques for noise suppression and contrast enhancement have been developed and implemented in order to facilitate visual analysis of on-line portal images. Results obtained with phantom and clinical images indicate that improvement in image quality can be achieved using adaptive filtering and local histogram modification. A novel study of observer performance with on-line portal images showed that enhancement of contrast by selective local histogram modification significantly improves perceptibility of anatomical landmarks and assures higher accuracy in quantitative computer-assisted treatment verification. Fully automated treatment verification is the ultimate goal of on-line digital portal imaging. It should include analysis of size and shape of the radiation field as well as evaluation of placement of the field with respect to the internal anatomy of the patient. A computerized technique, has been developed, for extraction of the treatment field edges and for parametrization of the field, and examples of its application to automated analysis of size and shape of the radiation field are presented.

  15. A summary of image segmentation techniques

    NASA Technical Reports Server (NTRS)

    Spirkovska, Lilly

    1993-01-01

    Machine vision systems are often considered to be composed of two subsystems: low-level vision and high-level vision. Low level vision consists primarily of image processing operations performed on the input image to produce another image with more favorable characteristics. These operations may yield images with reduced noise or cause certain features of the image to be emphasized (such as edges). High-level vision includes object recognition and, at the highest level, scene interpretation. The bridge between these two subsystems is the segmentation system. Through segmentation, the enhanced input image is mapped into a description involving regions with common features which can be used by the higher level vision tasks. There is no theory on image segmentation. Instead, image segmentation techniques are basically ad hoc and differ mostly in the way they emphasize one or more of the desired properties of an ideal segmenter and in the way they balance and compromise one desired property against another. These techniques can be categorized in a number of different groups including local vs. global, parallel vs. sequential, contextual vs. noncontextual, interactive vs. automatic. In this paper, we categorize the schemes into three main groups: pixel-based, edge-based, and region-based. Pixel-based segmentation schemes classify pixels based solely on their gray levels. Edge-based schemes first detect local discontinuities (edges) and then use that information to separate the image into regions. Finally, region-based schemes start with a seed pixel (or group of pixels) and then grow or split the seed until the original image is composed of only homogeneous regions. Because there are a number of survey papers available, we will not discuss all segmentation schemes. Rather than a survey, we take the approach of a detailed overview. We focus only on the more common approaches in order to give the reader a flavor for the variety of techniques available yet present enough

  16. Functional magnetic resonance imaging: imaging techniques and contrast mechanisms.

    PubMed Central

    Howseman, A M; Bowtell, R W

    1999-01-01

    Functional magnetic resonance imaging (fMRI) is a widely used technique for generating images or maps of human brain activity. The applications of the technique are widespread in cognitive neuroscience and it is hoped they will eventually extend into clinical practice. The activation signal measured with fMRI is predicated on indirectly measuring changes in the concentration of deoxyhaemoglobin which arise from an increase in blood oxygenation in the vicinity of neuronal firing. The exact mechanisms of this blood oxygenation level dependent (BOLD) contrast are highly complex. The signal measured is dependent on both the underlying physiological events and the imaging physics. BOLD contrast, although sensitive, is not a quantifiable measure of neuronal activity. A number of different imaging techniques and parameters can be used for fMRI, the choice of which depends on the particular requirements of each functional imaging experiment. The high-speed MRI technique, echo-planar imaging provides the basis for most fMRI experiments. The problems inherent to this method and the ways in which these may be overcome are particularly important in the move towards performing functional studies on higher field MRI systems. Future developments in techniques and hardware are also likely to enhance the measurement of brain activity using MRI. PMID:10466145

  17. Retinal Image Simulation of Subjective Refraction Techniques.

    PubMed

    Perches, Sara; Collados, M Victoria; Ares, Jorge

    2016-01-01

    Refraction techniques make it possible to determine the most appropriate sphero-cylindrical lens prescription to achieve the best possible visual quality. Among these techniques, subjective refraction (i.e., patient's response-guided refraction) is the most commonly used approach. In this context, this paper's main goal is to present a simulation software that implements in a virtual manner various subjective-refraction techniques--including Jackson's Cross-Cylinder test (JCC)--relying all on the observation of computer-generated retinal images. This software has also been used to evaluate visual quality when the JCC test is performed in multifocal-contact-lens wearers. The results reveal this software's usefulness to simulate the retinal image quality that a particular visual compensation provides. Moreover, it can help to gain a deeper insight and to improve existing refraction techniques and it can be used for simulated training.

  18. Red flag imaging techniques in Barrett's esophagus.

    PubMed

    Saxena, Payal; Canto, Marcia Irene

    2013-07-01

    The key to detection and treatment of early neoplasia in Barrett's esophagus (BE) is thorough and careful inspection of the Barrett's segment. The greatest role for red flag techniques is to help identify neoplastic lesions for targeted biopsy and therapy. High-definition white light endoscopy (HD-WLE) can potentially improve endoscopic imaging of BE compared with standard endoscopy, but little scientific evidence supports this. The addition of autofluorescence imaging to HD-WLE and narrow band imaging increases sensitivity and the false-positive rate without significantly improving overall detection of BE-related neoplasia.

  19. Digital imaging techniques in experimental stress analysis

    NASA Technical Reports Server (NTRS)

    Peters, W. H.; Ranson, W. F.

    1982-01-01

    Digital imaging techniques are utilized as a measure of surface displacement components in laser speckle metrology. An image scanner which is interfaced to a computer records and stores in memory the laser speckle patterns of an object in a reference and deformed configuration. Subsets of the deformed images are numerically correlated with the references as a measure of surface displacements. Discrete values are determined around a closed contour for plane problems which then become input into a boundary integral equation method in order to calculate surface traction in the contour. Stresses are then calculated within this boundary. The solution procedure is illustrated by a numerical example of a case of uniform tension.

  20. Angular Differential Imaging: a Powerful High-Contrast Imaging Technique

    SciTech Connect

    Marois, C; Lafreniere, D; Doyon, R; Macintosh, B; Nadeau, D

    2005-11-07

    Angular differential imaging is a high-contrast imaging technique that reduces speckle noise from quasi-static optical aberrations and facilitates the detection of faint nearby companions. A sequence of images is acquired with an altitude/azimuth telescope, the instrument rotator being turned off. This keeps the instrument and telescope optics aligned, stabilizes the instrumental PSF and allows the field of view to rotate with respect to the instrument. For each image, a reference PSF obtained from other images of the sequence is subtracted. All residual images are then rotated to align the field and are median combined. Observed performances are reported for Gemini Altair/NIRI data. Inside the speckle dominated region of the PSF, it is shown that quasi-static PSF noise can be reduced by a factor {approx}5 for each image subtraction. The combination of all residuals then provides an additional gain of the order of the square root of the total number of images acquired. To our knowledge, this is the first time an acquisition strategy and reduction pipeline designed for speckle attenuation and high contrast imaging is demonstrated to significantly get better detection limits with longer integration times at all angular separations. A PSF noise attenuation of 100 was achieved from 2-hour long sequences of images of Vega, reaching a 5-sigma contrast of 20 magnitudes for separations greater than 7''. This technique can be used with currently available instruments to search for {approx} 1 M{sub Jup} exoplanets with orbits of radii between 50 and 300 AU around nearby young stars. The possibility of combining the technique with other high-contrast imaging methods is briefly discussed.

  1. Surface definition technique for clinical imaging

    NASA Astrophysics Data System (ADS)

    Liao, Wen-gen; Simovsky, Ilya; Li, Andrew; Kramer, David M.; Kaufman, Leon; Rhodes, Michael L.

    1991-05-01

    Surface descriptions are difficult to specify. Though image processing techniques are well established to generate nearly any planar or three-dimensionally curved surface, methods to describe such complex shapes are often disorienting. Even the best intentioned interface for surface description can confuse a seasoned user. This paper introduces a surface definition technique that is simple, accurate and intuitive for the needs of routine medical image analysis. We describe a procedure to define a curved surface based on surface intersection points in a series of parallel images. In this medical context, points selected describe a surface that contains pathology of diagnostic interest. Using this technique diagnostic views are generated that conform to natural anatomic shape, physicians are no longer restricted to orthogonal or even single curve surfaces. This user interface provides analytic descriptions to produce surface views that use a Fourier-shift technique for reconstruction. Surfaces through a volume are produced with resolution equal to that of the original data set. Example images are illustrated.

  2. Retinal Imaging Techniques for Diabetic Retinopathy Screening

    PubMed Central

    Goh, James Kang Hao; Cheung, Carol Y.; Sim, Shaun Sebastian; Tan, Pok Chien; Tan, Gavin Siew Wei; Wong, Tien Yin

    2016-01-01

    Due to the increasing prevalence of diabetes mellitus, demand for diabetic retinopathy (DR) screening platforms is steeply increasing. Early detection and treatment of DR are key public health interventions that can greatly reduce the likelihood of vision loss. Current DR screening programs typically employ retinal fundus photography, which relies on skilled readers for manual DR assessment. However, this is labor-intensive and suffers from inconsistency across sites. Hence, there has been a recent proliferation of automated retinal image analysis software that may potentially alleviate this burden cost-effectively. Furthermore, current screening programs based on 2-dimensional fundus photography do not effectively screen for diabetic macular edema (DME). Optical coherence tomography is becoming increasingly recognized as the reference standard for DME assessment and can potentially provide a cost-effective solution for improving DME detection in large-scale DR screening programs. Current screening techniques are also unable to image the peripheral retina and require pharmacological pupil dilation; ultra-widefield imaging and confocal scanning laser ophthalmoscopy, which address these drawbacks, possess great potential. In this review, we summarize the current DR screening methods using various retinal imaging techniques, and also outline future possibilities. Advances in retinal imaging techniques can potentially transform the management of patients with diabetes, providing savings in health care costs and resources. PMID:26830491

  3. Imaging Instrumentation and Techniques for Precision Radiotherapy

    NASA Astrophysics Data System (ADS)

    Parodi, Katia; Parodi, Katia; Thieke, Christian; Thieke, Christian

    Over the last decade, several technological advances have considerably improved the achievable precision of dose delivery in radiation therapy. Clinical exploitation of the superior tumor-dose conformality offered by modern radiotherapy techniques like intensity-modulated radiotherapy and ion beam therapy requires morphological and functional assessment of the tumor during the entire therapy chain from treatment planning to beam application and treatment response evaluation. This chapter will address the main rationale and role of imaging in state-of-the-art external beam radiotherapy. Moreover, it will present the status of novel imaging instrumentation and techniques being nowadays introduced in clinical use or still under development for image guidance and, ultimately, dose guidance of precision radiotherapy.

  4. Generative technique for dynamic infrared image sequences

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Cao, Zhiguo; Zhang, Tianxu

    2001-09-01

    The generative technique of the dynamic infrared image was discussed in this paper. Because infrared sensor differs from CCD camera in imaging mechanism, it generates the infrared image by incepting the infrared radiation of scene (including target and background). The infrared imaging sensor is affected deeply by the atmospheric radiation, the environmental radiation and the attenuation of atmospheric radiation transfers. Therefore at first in this paper the imaging influence of all kinds of the radiations was analyzed and the calculation formula of radiation was provided, in addition, the passive scene and the active scene were analyzed separately. Then the methods of calculation in the passive scene were provided, and the functions of the scene model, the atmospheric transmission model and the material physical attribute databases were explained. Secondly based on the infrared imaging model, the design idea, the achievable way and the software frame for the simulation software of the infrared image sequence were introduced in SGI workstation. Under the guidance of the idea above, in the third segment of the paper an example of simulative infrared image sequences was presented, which used the sea and sky as background and used the warship as target and used the aircraft as eye point. At last the simulation synthetically was evaluated and the betterment scheme was presented.

  5. Advanced automated char image analysis techniques

    SciTech Connect

    Tao Wu; Edward Lester; Michael Cloke

    2006-05-15

    Char morphology is an important characteristic when attempting to understand coal behavior and coal burnout. In this study, an augmented algorithm has been proposed to identify char types using image analysis. On the basis of a series of image processing steps, a char image is singled out from the whole image, which then allows the important major features of the char particle to be measured, including size, porosity, and wall thickness. The techniques for automated char image analysis have been tested against char images taken from ICCP Char Atlas as well as actual char particles derived from pyrolyzed char samples. Thirty different chars were prepared in a drop tube furnace operating at 1300{sup o}C, 1% oxygen, and 100 ms from 15 different world coals sieved into two size fractions (53-75 and 106-125 {mu}m). The results from this automated technique are comparable with those from manual analysis, and the additional detail from the automated sytem has potential use in applications such as combustion modeling systems. Obtaining highly detailed char information with automated methods has traditionally been hampered by the difficulty of automatic recognition of individual char particles. 20 refs., 10 figs., 3 tabs.

  6. Order of magnitude reduction of fluoroscopic x-ray dose

    NASA Astrophysics Data System (ADS)

    Bal, Abhinav; Robert, Normand; Machan, Lindsay; Deutsch, Meir; Kisselgoff, David; Babyn, Paul; Rowlands, John A.

    2012-03-01

    The role of fluoroscopic imaging is critical for diagnostic and image guided therapy. However, fluoroscopic imaging can require significant radiation leading to increased cancer risk and non-stochastic effects such as radiation burns. Our purpose is to reduce the exposure and dose to the patient by an order of magnitude in these procedures by use of the region of interest method. Method and Materials: Region of interest fluoroscopy (ROIF) uses a partial attenuator. The central region of the image has full exposure while the image periphery, there to provide context only, has a reduced exposure rate. ROIF using a static partial attenuator has been shown in our previous studies to reduce the dose area product (DAP) to the patient by at least 2.5 times. Significantly greater reductions in DAP would require improvements in flat panel detectors performance at low x-ray exposures or a different x-ray attenuation strategy. Thus we have investigated a second, dynamic, approach. We have constructed an x-ray shutter system allowing a normal x-ray exposure in the region of interest while reducing the number of x-ray exposures in the periphery through the rapid introduction, positioning and removal of an x-ray attenuating shutter to block radiation only for selected frames. This dynamic approach eliminates the DQE(0) loss associated with the use of static partial attenuator applied to every frame thus permitting a greater reduction in DAP. Results: We have compared the two methods by modeling and determined their fundamental limits.

  7. Techniques for millimetre-wave imaging

    NASA Astrophysics Data System (ADS)

    Lettington, Alan H.; Dunn, Dennis; Alexander, Naomi E.; Wabby, Anas; Chen, Chun-Hong

    2004-12-01

    This paper reviews the formation of an image with coherent and incoherent radiation. It discusses the various mm-wave methods for electronic beam-forming and beam-steering such as phased array, leaky-wave antennas, up-conversion, tapped delay lines and digital beam-forming techniques. These methods are related in the paper to their optical analogues of beam-forming and steering by a lens and the measurement of the aperture function in the case of holography. It concludes that digital techniques will be used in the future when the cost of receivers is reduced but that at present opto-mechanical techniques are more cost effective. A high efficiency, compact opto-mechanical system is described. This is able to operate at any wavelength and be active or passive. Typical 94GHz images are presented.

  8. Retinal Image Simulation of Subjective Refraction Techniques

    PubMed Central

    Perches, Sara; Collados, M. Victoria; Ares, Jorge

    2016-01-01

    Refraction techniques make it possible to determine the most appropriate sphero-cylindrical lens prescription to achieve the best possible visual quality. Among these techniques, subjective refraction (i.e., patient’s response-guided refraction) is the most commonly used approach. In this context, this paper’s main goal is to present a simulation software that implements in a virtual manner various subjective-refraction techniques—including Jackson’s Cross-Cylinder test (JCC)—relying all on the observation of computer-generated retinal images. This software has also been used to evaluate visual quality when the JCC test is performed in multifocal-contact-lens wearers. The results reveal this software’s usefulness to simulate the retinal image quality that a particular visual compensation provides. Moreover, it can help to gain a deeper insight and to improve existing refraction techniques and it can be used for simulated training. PMID:26938648

  9. Adrenal imaging (Part 1): Imaging techniques and primary cortical lesions

    PubMed Central

    Panda, Ananya; Das, Chandan J.; Dhamija, Ekta; Kumar, Rakesh; Gupta, A. K.

    2015-01-01

    Adrenal glands can be affected by a variety of lesions. Adrenal lesions can either be primary, of adrenal origin, or secondary to other pathologies. Primary adrenal lesions can further be either of cortical or medullary origin. Functioning adrenal lesions can also give clues to the histologic diagnosis and direct workup. Over the years, various imaging techniques have been developed that have increased diagnostic accuracy and helped in better characterization of adrenal lesions non-invasively. In the first part of the two part series, we review adrenal imaging techniques and adrenal cortical tumors such as adenomas, adrenocortical tumors, adrenal hyperplasia and oncocytomas. PMID:25593820

  10. Image processing techniques for passive millimeter-wave imaging

    NASA Astrophysics Data System (ADS)

    Lettington, Alan H.; Gleed, David G.

    1998-08-01

    We present our results on the application of image processing techniques for passive millimeter-wave imaging and discuss possible future trends. Passive millimeter-wave imaging is useful in poor weather such as in fog and cloud. Its spatial resolution, however, can be restricted due to the diffraction limit of the front aperture. Its resolution may be increased using super-resolution techniques but often at the expense of processing time. Linear methods may be implemented in real time but non-linear methods which are required to restore missing spatial frequencies are usually more time consuming. In the present paper we describe fast super-resolution techniques which are potentially capable of being applied in real time. Associated issues such as reducing the influence of noise and improving recognition capability will be discussed. Various techniques have been used to enhance passive millimeter wave images giving excellent results and providing a significant quantifiable increase in spatial resolution. Examples of applying these techniques to imagery will be given.

  11. In vitro imaging techniques in neurodegenerative diseases.

    PubMed

    Långström, Bengt; Andrén, Per E; Lindhe, Orjan; Svedberg, Marie; Hall, Håkan

    2007-01-01

    Neurodegeneration induces various changes in the brain, changes that may be investigated using neuroimaging techniques. The in vivo techniques are useful for the visualization of major changes, and the progressing abnormalities may also be followed longitudinally. However, to study and quantify minor abnormalities, neuroimaging of postmortem brain tissue is used. These in vitro methods are complementary to the in vivo techniques and contribute to the knowledge of pathophysiology and etiology of the neurodegenerative diseases. In vitro radioligand autoradiography has given great insight in the involvement of different neuronal receptor systems in these diseases. Data on the dopamine and cholinergic systems in neurodegeneration are discussed in this review. Also, the amyloid plaques are studied using in vitro radioligand autoradiography. Using one of the newer methods, imaging matrix-assisted laser desorption ionization mass spectrometry, the distribution of a large number of peptides and proteins may be detected in vitro on brain cryosections. In this overview, we describe in vitro imaging techniques in the neurodegenerative diseases as a complement to in vivo positron emission tomography and single photon emission computed tomography imaging.

  12. Combining calcium imaging with other optical techniques.

    PubMed

    Canepari, Marco; Zecevic, Dejan; Vogt, Kaspar E; Ogden, David; De Waard, Michel

    2013-12-01

    Ca(2+) imaging is a commonly used approach for measuring Ca(2+) signals at high spatial resolution. The method is often combined with electrode recordings to correlate electrical and chemical signals or to investigate Ca(2+) signals following an electrical stimulation. To obtain information on electrical activity at the same spatial resolution, Ca(2+) imaging must be combined with membrane potential imaging. Similarly, stimulation of subcellular compartments requires photostimulation. Thus, combining Ca(2+) imaging with an additional optical technique facilitates the study of a number of physiological questions. The aim of this article is to introduce some basic principles regarding the combination of Ca(2+) imaging with other optical techniques. We discuss the design of the optics, the design of experimental protocols, the optical characteristics of Ca(2+) indicators used in combination with an optical probe, and the affinity of the Ca(2+) indicator in relation to the type of measurement. This information will enable the reader to devise an optimal strategy for combined optical experiments.

  13. Vascular Imaging Techniques of the Spinal Cord.

    PubMed

    Vargas, Maria Isabel; Barnaure, Isabelle; Gariani, Joanna; Boto, José; Pellaton, Alain; Dietemann, Jean-Louis; Kulcsar, Zsolt

    2017-04-01

    The various imaging techniques used to depict vascular lesions of the spinal cord are described in this article with particular emphasis on magnetic resonance imaging (MRI), vascular sequences, and advantages of high-field MRI. Technical vascular protocols are discussed in computed tomography, MRI, and conventional angiography. The diverse magnetic resonance angiography protocols are presented as well as their findings, specificities, and pitfalls. A review of the vascular anatomy and the most common pathologies analyzed by magnetic resonance angiography and conventional angiography is described.

  14. Image Recognition Techniques for Gamma Spectroscopy

    SciTech Connect

    Vlachos, D. S.; Tsabaris, C. G.

    2007-12-26

    Photons, after generated from a radioactive source and before they deposit their energy in a photo detector, are subsequent to multiple scattering mechanisms. As a result, the measured energy from the photo detector is different from the energy the photon had when generated. This is known as folding of the photon energy. Moreover, statistical fluctuation inside the detector contribute to energy folding. In this work, a new method is presented for unfolding the gamma ray spectrum. The method uses a 2-dimensional representation of the measured spectrum (image) and then uses image recognition techniques, and especially differential edge detection, to generate the original spectrum.

  15. [Imaging techniques in modern trauma diagnostics].

    PubMed

    Vogl, T J; Eichler, K; Marzi, I; Wutzler, S; Zacharowski, K; Frellessen, C

    2017-08-17

    Modern trauma room management requires interdisciplinary teamwork and synchronous communication between a team of anaesthesists, surgeons and radiologists. As the length of stay in the trauma room influences morbidity and mortality of a severely injured person, optimizing time is one of the main targets. With the direct involvement of modern imaging techniques the injuries caused by trauma should be detected within a very short period of time in order to enable a priority-orientated treatment. Radiology influences structure and process quality, management and development of trauma room algorithms regarding the use of imaging techniques. For the individual case interventional therapy methods can be added. Based on current data and on the Frankfurt experience the current diagnostic concepts of trauma diagnostics are presented.

  16. [Imaging techniques in modern trauma diagnostics].

    PubMed

    Vogl, T J; Eichler, K; Marzi, I; Wutzler, S; Zacharowski, K; Frellessen, C

    2017-05-01

    Modern trauma room management requires interdisciplinary teamwork and synchronous communication between a team of anaesthesists, surgeons and radiologists. As the length of stay in the trauma room influences morbidity and mortality of a severely injured person, optimizing time is one of the main targets. With the direct involvement of modern imaging techniques the injuries caused by trauma should be detected within a very short period of time in order to enable a priority-orientated treatment. Radiology influences structure and process quality, management and development of trauma room algorithms regarding the use of imaging techniques. For the individual case interventional therapy methods can be added. Based on current data and on the Frankfurt experience the current diagnostic concepts of trauma diagnostics are presented.

  17. [Imaging techniques in modern trauma diagnostics].

    PubMed

    Vogl, T J; Eichler, K; Marzi, I; Wutzler, S; Zacharowski, K; Frellessen, C

    2017-09-21

    Modern trauma room management requires interdisciplinary teamwork and synchronous communication between a team of anaesthesists, surgeons and radiologists. As the length of stay in the trauma room influences morbidity and mortality of a severely injured person, optimizing time is one of the main targets. With the direct involvement of modern imaging techniques the injuries caused by trauma should be detected within a very short period of time in order to enable a priority-orientated treatment. Radiology influences structure and process quality, management and development of trauma room algorithms regarding the use of imaging techniques. For the individual case interventional therapy methods can be added. Based on current data and on the Frankfurt experience the current diagnostic concepts of trauma diagnostics are presented.

  18. Imaging In focus: Reflected light imaging: Techniques and applications.

    PubMed

    Guggenheim, Emily J; Lynch, Iseult; Rappoport, Joshua Z

    2017-02-01

    Reflectance imaging is a broad term that describes the formation of images by the detection of illumination light that is back-scattered from reflective features within a sample. Reflectance imaging can be performed in a variety of different configurations, such as confocal, oblique angle illumination, structured illumination, interferometry and total internal reflectance, permitting a plethora of biomedical applications. Reflectance imaging has proven indispensable for critical investigations into the safety and understanding of biomedically and environmentally relevant nano-materials, an area of high priority and investment. The non-destructive in vivo imaging ability of reflectance techniques permits alternative diagnostic strategies that may eventually facilitate the eradication of some invasive biopsy procedures. Reflectance can also provide additional structural information and clarity necessary in fluorescent based in vivo studies. Near-coverslip interrogation techniques, such as reflectance interferometry and total internal reflection, have provided a label free means to investigate cell-surface contacts, cell motility and vesicle trafficking in vivo and in vitro. Other key advances include the ability to acquire superresolution reflectance images providing increased spatial resolution.

  19. Lunar surface chemistry: A new imaging technique

    USGS Publications Warehouse

    Andre, C.G.; Bielefeld, M.J.; Eliason, E.; Soderblom, L.A.; Adler, I.; Philpotts, J.A.

    1977-01-01

    Detailed chemical maps of the lunar surface have been constructed by applying a new weighted-filter imaging technique to Apollo 15 and Apollo 16 x-ray fluorescence data. The data quality improvement is amply demonstrated by (i) modes in the frequency distribution, representing highland and mare soil suites, which are not evident before data filtering and (ii) numerous examples of chemical variations which are correlated with small-scale (about 15 kilometer) lunar topographic features.

  20. Imaging Body Fat: Techniques and Cardiometabolic Implications

    PubMed Central

    Wang, H.; Chen, Y. E; Eitzman, D.T.

    2014-01-01

    Obesity is a world-wide epidemic and is associated with multiple comorbidities. The mechanisms underlying the relationship between obesity and adverse health outcomes remain poorly understood. This may be due to several factors including the crude measures used to estimate adiposity, the striking heterogeneity between adipose tissue depots, and the influence of fat accumulation in multiple organs. In order to advance our understanding of fat stores and associated co-morbidities in humans, it will be necessary to image adiposity throughout the body and ultimately also assess its functionality. Large clinical studies are demonstrating the prognostic importance of adipose tissue imaging. Newer techniques capable of imaging fat metabolism and other functions of adipose tissue may provide additional prognostic utility and may be useful in guiding therapeutic interventions. PMID:25147343

  1. Biometric Identification Using Holographic Radar Imaging Techniques

    SciTech Connect

    McMakin, Douglas L.; Sheen, David M.; Hall, Thomas E.; Kennedy, Mike O.; Foote, Harlan P.

    2007-04-01

    Pacific Northwest National Laboratory researchers have been at the forefront of developing innovative screening systems to enhance security and a novel imaging system to provide custom-fit clothing using holographic radar imaging techniques. First-of-a-kind cylindrical holographic imaging systems have been developed to screen people at security checkpoints for the detection of concealed, body worn, non-metallic threats such as plastic and liquid explosives, knifes and contraband. Another embodiment of this technology is capable of obtaining full sized body measurements in near real time without the person under surveillance removing their outer garments. Radar signals readily penetrate clothing and reflect off the water in skin. This full body measurement system is commercially available for best fitting ready to wear clothing, which was the first “biometric” application for this technology. One compelling feature of this technology for security biometric applications is that it can see effectively through disguises, appliances and body hair.

  2. Biometric identification using holographic radar imaging techniques

    NASA Astrophysics Data System (ADS)

    McMakin, Douglas L.; Sheen, David M.; Hall, Thomas E.; Kennedy, Mike O.; Foote, Harlen P.

    2007-04-01

    Pacific Northwest National Laboratory researchers have been at the forefront of developing innovative screening systems to enhance security and a novel imaging system to provide custom-fit clothing using holographic radar imaging techniques. First-of-a-kind cylindrical holographic imaging systems have been developed to screen people at security checkpoints for the detection of concealed, body worn, non-metallic threats such as plastic and liquid explosives, knifes and contraband. Another embodiment of this technology is capable of obtaining full sized body measurements in near real time without the person under surveillance removing their outer garments. Radar signals readily penetrate clothing and reflect off the water in skin. This full body measurement system is commercially available for best fitting ready to wear clothing, which was the first "biometric" application for this technology. One compelling feature of this technology for security biometric applications is that it can see effectively through disguises, appliances and body hair.

  3. Diagnostic imaging techniques in thyroid cancer

    SciTech Connect

    Friedman, M.; Toriumi, D.M.; Mafee, M.F.

    1988-02-01

    With the refinement of fine-needle aspiration, the specific applications of thyroid imaging techniques need to be reevaluated for efficiency and cost containment. No thyroid imaging test should be routinely obtained. Radionuclide scanning is most beneficial in evaluating the functional status of thyroid nodules when fine-needle aspiration is inadequate, the findings are benign, or when there is no discrete nodule that is palpated in an enlarged gland. When fine-needle aspiration is unavailable or unreliable, radionuclide scanning becomes a first-line diagnostic tool. Ultrasonography should be used primarily for identifying a solid component of a cystic nodule, determining the size of nodules on thyroxine suppression that are not easily palpable, or for performing guided fine-needle aspiration. Computerized tomography and magnetic resonance imaging both have a definite role in the evaluation of thyroid tumors. Magnetic resonance imaging is superior to computerized tomography for the evaluation of metastatic, retrotracheal, or mediastinal involvement of large thyroid tumors or goiters. Careful selection of the diagnostic techniques will ensure more accurate diagnosis and reduce unnecessary patient costs in the treatment of thyroid cancer.

  4. Resolution enhancement techniques for halftoned images

    NASA Astrophysics Data System (ADS)

    Ryu, Byong Tae; Lee, Jong Ok; Kim, Choon-Woo; Lee, Ho Keun; Kim, Sang Ho

    2007-01-01

    Recently, speed and resolution of electrophotographic printer engine have been significantly improved. In today's market, it is not difficult to find low to mid-end electrophotographic printers with the spatial resolution greater than 600 dpi and/or bit-depth resolution more than 1 bit. Printing speed is determined by the processing time at computer, data transmission time between computer and printer, and processing and printing time at printer. When halftoning is performed at computer side, halftoned data would be compressed and sent to printer. In this case, increase in the spatial and bit-depth resolution would increase data size to be transmitted and memory size at printer. For a high-speed printer, increased transmission time may limit the throughput in imaging chain. One of possible solutions to this problem is to develop resolution enhancement techniques. In this paper, a fast and efficient spatial resolution enhancement technique is proposed. Objectives of the proposed technique are to reduce the data size for transmission and minimize image quality deterioration. In the proposed technique, number of black pixels in the halftoned data is binary coded for data reduction. At printer, black pixel placement algorithm is applied to binary coded data. For non-edge area, screen order is utilized for the black pixel placement. When identified as edge area, locations of black pixels are selected by the edge order designed by genetic algorithm.

  5. Reducing Radiation Exposure in an Electrophysiology Lab with Introduction of Newer Fluoroscopic Technology.

    PubMed

    Sharma, Munish; Khalighi, Koroush

    2017-06-07

    The use of fluoroscopic devices exposes patients and operators to harmful effects of ionizing radiation in an electrophysiology (EP) lab. We sought to know if the newer fluoroscopic technology (Allura Clarity) installed in a hybrid EP helps to reduce prescribed radiation dose. We performed radiation dose analysis of 90 patients who underwent various procedures in the EP lab at a community teaching hospital after the introduction of newer fluoroscopic technology in June of 2016. Watchman device insertion, radiofrequency ablation procedures, permanent pacemaker (PPM)/implantable cardioverter defibrillator (ICD) placement and battery changes were included in the study to compare radiation exposure during different procedures performed commonly in an EP lab. In all cases of watchman device placement, radiofrequency ablation procedures, PPM/ICD placement and battery changes, there was a statistically significant difference (<0.05) in radiation dose exposure. Significant reduction in radiation exposure during various procedures performed in an EP lab was achieved with aid of newer fluoroscopic technology and better image detection technology.

  6. Sequential dual-energy subtraction technique with a dynamic flat-panel detector (FPD): primary study for image-guided radiation therapy (IGRT).

    PubMed

    Tanaka, Rie; Sanada, Shigeru; Matsui, Takeshi; Hayashi, Norio; Matsui, Osamu

    2008-07-01

    A sequential dual-energy subtraction technique for image-guided radiation therapy (IGRT) was developed. Here, we report on a computerized method for creating sequential soft-tissue images and the accuracy of tracking targets on the images obtained, in comparison to conventional fluoroscopic images. Two sets of sequential chest images during respiration of a normal subject were obtained with X-rays of different energy separately with a flat-panel detector (FPD). Sequential soft-tissue images were created from the two sets of sequential images consisting of real-time images and reference template images, respectively. The creation of sequential soft-tissue images consisted of three steps: one-to-one image correspondence of the two sequential images, image registration, and image subtraction in each frame. Motion tracking of lung vessels was then performed by the template-matching technique. For evaluation of the accuracy of motion tracking on the sequential soft-tissue images, the results were compared with those on the original sequential images. Sequential soft-tissue images provided more accurate tracking than the original images (P < 0.01). There was no significant error throughout all frames in the soft-tissue images, whereas the rib shadow introduced a tracking error in the original images. The maximum errors were 4.1 +/- 0.3 mm in the sequential soft-tissue images and 28.1 +/- 20.0 mm in the original images. In conclusion, sequential soft-tissue images were helpful for tracking of a target affected by respiratory motion. Dual-energy subtraction has the potential to improve the accuracy of IGRT without implanted markers.

  7. Robustness of speckle imaging techniques applied to horizontal imaging scenarios

    NASA Astrophysics Data System (ADS)

    Bos, Jeremy P.

    Atmospheric turbulence near the ground severely limits the quality of imagery acquired over long horizontal paths. In defense, surveillance, and border security applications, there is interest in deploying man-portable, embedded systems incorporating image reconstruction to improve the quality of imagery available to operators. To be effective, these systems must operate over significant variations in turbulence conditions while also subject to other variations due to operation by novice users. Systems that meet these requirements and are otherwise designed to be immune to the factors that cause variation in performance are considered robust. In addition to robustness in design, the portable nature of these systems implies a preference for systems with a minimum level of computational complexity. Speckle imaging methods are one of a variety of methods recently been proposed for use in man-portable horizontal imagers. In this work, the robustness of speckle imaging methods is established by identifying a subset of design parameters that provide immunity to the expected variations in operating conditions while minimizing the computation time necessary for image recovery. This performance evaluation is made possible using a novel technique for simulating anisoplanatic image formation. I find that incorporate as few as 15 image frames and 4 estimates of the object phase per reconstructed frame provide an average reduction of 45% reduction in Mean Squared Error (MSE) and 68% reduction in deviation in MSE. In addition, the Knox-Thompson phase recovery method is demonstrated to produce images in half the time required by the bispectrum. Finally, it is shown that certain blind image quality metrics can be used in place of the MSE to evaluate reconstruction quality in field scenarios. Using blind metrics rather depending on user estimates allows for reconstruction quality that differs from the minimum MSE by as little as 1%, significantly reducing the deviation in

  8. Special feature on imaging systems and techniques

    NASA Astrophysics Data System (ADS)

    Yang, Wuqiang; Giakos, George

    2013-07-01

    The IEEE International Conference on Imaging Systems and Techniques (IST'2012) was held in Manchester, UK, on 16-17 July 2012. The participants came from 26 countries or regions: Austria, Brazil, Canada, China, Denmark, France, Germany, Greece, India, Iran, Iraq, Italy, Japan, Korea, Latvia, Malaysia, Norway, Poland, Portugal, Sweden, Switzerland, Taiwan, Tunisia, UAE, UK and USA. The technical program of the conference consisted of a series of scientific and technical sessions, exploring physical principles, engineering and applications of new imaging systems and techniques, as reflected by the diversity of the submitted papers. Following a rigorous review process, a total of 123 papers were accepted, and they were organized into 30 oral presentation sessions and a poster session. In addition, six invited keynotes were arranged. The conference not only provided the participants with a unique opportunity to exchange ideas and disseminate research outcomes but also paved a way to establish global collaboration. Following the IST'2012, a total of 55 papers, which were technically extended substantially from their versions in the conference proceeding, were submitted as regular papers to this special feature of Measurement Science and Technology . Following a rigorous reviewing process, 25 papers have been finally accepted for publication in this special feature and they are organized into three categories: (1) industrial tomography, (2) imaging systems and techniques and (3) image processing. These papers not only present the latest developments in the field of imaging systems and techniques but also offer potential solutions to existing problems. We hope that this special feature provides a good reference for researchers who are active in the field and will serve as a catalyst to trigger further research. It has been our great pleasure to be the guest editors of this special feature. We would like to thank the authors for their contributions, without which it would

  9. Advanced Imaging Techniques for Multiphase Flows Analysis

    NASA Astrophysics Data System (ADS)

    Amoresano, A.; Langella, G.; Di Santo, M.; Iodice, P.

    2017-08-01

    Advanced numerical techniques, such as fuzzy logic and neural networks have been applied in this work to digital images acquired on two applications, a centrifugal pump and a stationary spray in order to define, in a stochastic way, the gas-liquid interface evolution. Starting from the numeric matrix representing the image it is possible to characterize geometrical parameters and the time evolution of the jet. The algorithm used works with the fuzzy logic concept to binarize the chromatist of the pixels, depending them, by using the difference of the light scattering for the gas and the liquid phase.. Starting from a primary fixed threshold, the applied technique, can select the ‘gas’ pixel from the ‘liquid’ pixel and so it is possible define the first most probably boundary lines of the spray. Acquiring continuously the images, fixing a frame rate, a most fine threshold can be select and, at the limit, the most probably geometrical parameters of the jet can be detected.

  10. Lung tumor tracking in fluoroscopic video based on optical flow.

    PubMed

    Xu, Qianyi; Hamilton, Russell J; Schowengerdt, Robert A; Alexander, Brian; Jiang, Steve B

    2008-12-01

    Respiratory gating and tumor tracking for dynamic multileaf collimator delivery require accurate and real-time localization of the lung tumor position during treatment. Deriving tumor position from external surrogates such as abdominal surface motion may have large uncertainties due to the intra- and interfraction variations of the correlation between the external surrogates and internal tumor motion. Implanted fiducial markers can be used to track tumors fluoroscopically in real time with sufficient accuracy. However, it may not be a practical procedure when implanting fiducials bronchoscopically. In this work, a method is presented to track the lung tumor mass or relevant anatomic features projected in fluoroscopic images without implanted fiducial markers based on an optical flow algorithm. The algorithm generates the centroid position of the tracked target and ignores shape changes of the tumor mass shadow. The tracking starts with a segmented tumor projection in an initial image frame. Then, the optical flow between this and all incoming frames acquired during treatment delivery is computed as initial estimations of tumor centroid displacements. The tumor contour in the initial frame is transferred to the incoming frames based on the average of the motion vectors, and its positions in the incoming frames are determined by fine-tuning the contour positions using a template matching algorithm with a small search range. The tracking results were validated by comparing with clinician determined contours on each frame. The position difference in 95% of the frames was found to be less than 1.4 pixels (approximately 0.7 mm) in the best case and 2.8 pixels (approximately 1.4 mm) in the worst case for the five patients studied.

  11. Imaging Techniques in Acute Heart Failure.

    PubMed

    Pérez del Villar, Candelas; Yotti, Raquel; Bermejo, Javier

    2015-07-01

    In recent years, imaging techniques have revolutionized the diagnosis of heart failure. In patients with a clinical picture of acute decompensation, prognosis is largely determined by early implementation of general measures and treatment of the underlying cause. Given its diagnostic yield and portability, ultrasound has become an essential tool in the setting of acute heart failure, and is currently found in all medical departments involved in the care of the critically ill patient. Cardiac magnetic resonance and computed tomography allow detailed characterization of multiple aspects of cardiac structure and function that were previously unavailable. This helps guide and monitor many of the treatment decisions in the acute heart failure population in an entirely noninvasive way. This article aims to review the usefulness of the imaging techniques that are clinically relevant in the context of an episode of acute heart failure. We discuss the indications and limitations of these techniques in detail and describe the general principles for the appropriate interpretation of results. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  12. SU-E-I-36: A Study to Compare Operator Dosimeter Exposure versus Fluoroscopic Time and Air Kerma in Fluoroscopically Guided Interventional Procedures.

    PubMed

    McKetty, M

    2012-06-01

    The total effective dose equivalent limit for occupationally radiation exposed persons has remained at 50 millisieverts per year since the 1960s. There is ongoing discussion whether this limit should be lowered. Whether or not it is lowered, all facilities have to adhere to the principle of ALARA (as low as reasonably achievable). In a hospital environment, the workers who typically have exposures which Result in ALARA investigations having to be performed include interventional radiologists, cardiologists, and mobile C-arm operators. At our institution there are a limited number of interventional radiologists with one person being responsible for performing the majority of the procedures and sometimes exceeding the ALARA investigational levels. A limited study was performed to compare the number, type of studies, cumulative air kerma, and fluoroscopic time versus the exposure measured by the personnel dosimeters worn by the radiologists. This was also related to the type of angiographic equipment in use. The length of fluoroscopic time and cumulative air kerma and cumulative DAP appeared to be related to the higher exposures received by the operator. The number of procedures performed did not correlate with the personnel dosimeter exposure; rather it was the type and complexity of a study and the length of fluoroscopic time that was related. The number of ALARA investigations required has decreased gradually. This could be attributed to several factors. These include increased use of available safety items. With an increase in the number of interventionalists the work load is distributed more equitably. The purchase of new angiographic equipment has resulted in better image quality and more shielding options for the operators. The operators are periodically reminded to keep fluoroscopic time to a minimum and use appropriate settings on the equipment. The equipment is calibrated to provide adequate image quality at mid-dose settings. © 2012 American Association of

  13. Fluoroscopic performance tests using a portable computer/frame grabber: Wiener spectra measurements.

    PubMed

    Goldman, L W

    1992-01-01

    Currently, routine tests of fluoroscopic image quality in common use are highly subjective. As part of an effort to develop more quantitative routine tests of fluoroscopic image quality, a method was developed to quickly and easily measure Wiener spectra (WS) of TV-viewed fluoroscopic systems that considers both spatial and temporal noise correlations. A PC-mounted frame grabber captures images at the TV frame rate to form a three-dimensional (3-D) array of pixels. Scans of a "two-dimensional slit" are then synthesized from which a one-dimensional central section of a 3-D WS is calculated. To avoid errors due to coarse (8-bit) quantization, a video amplifier is used to expand a portion of the signal to the full digitizer range. A reference signal (2 mm of aluminum) is then used to normalize image contrast. Ensemble averages of 250 spectra were obtained in approximately 1 min, including all processing. Results are presented to demonstrate reproducibility, sensitivity, and behavior of the WS. The eventual goal of this work is to use this method in conjunction with measurements of an MTF to calculate fundamental descriptors of image quality, such as SNR and NEQ.

  14. A new image calibration technique for colposcopic images

    NASA Astrophysics Data System (ADS)

    Li, Wenjing; Soto-Thompson, Marcelo; Xiong, Yizhi; Lange, Holger

    2006-03-01

    Colposcopy is a primary diagnostic method used to detect cancer and precancerous lesions of the uterine cervix. During the examination, the metaplastic and abnormal tissues exhibit different degrees of whiteness (acetowhitening effect) after applying a 3%-5% acetic acid solution. Colposcopists evaluate the color and density of the acetowhite tissue to assess the severity of lesions for the purpose of diagnosis, telemedicine, and annotation. However, the color and illumination of the colposcopic images vary with the light sources, the instruments and camera settings, as well as the clinical environments. This makes assessment of the color information very challenging even for an expert. In terms of developing a Computer-Aided Diagnosis (CAD) system for colposcopy, these variations affect the performance of the feature extraction algorithm for the acetowhite color. Non-uniform illumination from the light source is also an obstacle for detecting acetowhite regions, lesion margins and anatomic features. Therefore, in digital colposcopy, it is critical to map the color appearance of the images taken with different colposcopes into one standard color space with normalized illumination. This paper presents a novel image calibration technique for colposcopic images. First, a specially designed calibration unit is mounted on the colposcope to acquire daily calibration data prior to performing patient examinations. The calibration routine is fast, automated, accurate and reliable. We then use our illumination correction algorithm and a color calibration algorithm to calibrate the patient data. In this paper we describe these techniques and demonstrate their applications in clinical studies.

  15. Imaging techniques with refractive beam shaping optics

    NASA Astrophysics Data System (ADS)

    Laskin, Alexander; Laskin, Vadim

    2012-10-01

    Applying of the refractive beam shapers in real research optical setups as well as in industrial installations requires very often manipulation of a final laser spot size. In many cases this task can be easily solved by using various imaging optical layouts presuming creating an image of a beam shaper output aperture. Due to the unique features of the refractive beam shapers of field mapping type, like flat wave front and low divergence of the collimated resulting beam with flattop or another intensity profile, there is a freedom in building of various imaging systems with using ordinary optical components, including off-the-shelf ones. There will be considered optical layouts providing high, up to 1/200×, de-magnifying factors, combining of refractive beam shapers like πShaper with scanning systems, building of relay imaging systems with extended depth of field. These optical layouts are widely used in such laser technologies like drilling holes in PCB, welding, various micromachining techniques with galvo-mirror scanning, interferometry and holography, various SLM-based applications. Examples of real implementations and experimental results will be presented as well.

  16. Atherosclerosis staging: imaging using FLIM technique

    NASA Astrophysics Data System (ADS)

    Sicchieri, Leticia B.; Barioni, Marina Berardi; Silva, Mônica Nascimento; Monteiro, Andrea Moreira; Figueiredo Neto, Antonio Martins; Ito, Amando S.; Courrol, Lilia C.

    2014-03-01

    In this work it was used fluorescence lifetime imaging (FLIM) to analyze biochemical composition of atherosclerotic plaque. For this purpose an animal experimentation was done with New Zealand rabbits divided into two groups: a control group of 4 rabbits that received a regular diet for 0, 20, 40 and 60 days; and an experimental group of 9 rabbits, divided in 3 subgroups, that were fed with 1% cholesterol diet for 20, 40 and 60 days respectively. The aortas slices stained with europium chlortetracycline were analyzed by FLIM exciting samples at 440 nm. The results shown an increase in the lifetime imaging of rabbits fed with cholesterol. It was observed that is possible to detect the metabolic changes associated with atherosclerosis at an early stage using FLIM technique exciting the tissue around 440 nm and observing autofluorescence lifetime. Lifetimes longer than 1.75 ns suggest the presence of porphyrins in the tissue and consequently, inflammation and the presence of macrophages.

  17. SU-D-209-02: Percent Depth Dose Curves for Fluoroscopic X-Ray Beam Qualities Incorporating Copper Filtration

    SciTech Connect

    Wunderle, K; Godley, A; Shen, Z; Dong, F; Rakowski, J

    2016-06-15

    Purpose: The purpose of this investigation was to quantify percent depth dose (PDD) curves for fluoroscopic x-ray beam qualities incorporating added copper filtration. Methods: A PTW (Freiburg, Germany) MP3 water tank was used with a Standard Imaging (Middleton, WI) Exradin Model 11 Spokas Chamber to measure PDD curves for 60, 80, 100 and 120 kVp x-ray beams with copper filtration ranging from 0.0–0.9 mm at 22cm and 42cm fields of view from 0 to 150 mm of water. A free-in-air monitor chamber was used to normalize the water tank data to fluctuations in output from the fluoroscope. The measurements were acquired on a Siemens (Erlangen, Germany) Artis ZeeGo fluoroscope. The fluoroscope was inverted from the typical orientation providing an x-ray beam originating from above the water tank. The water tank was positioned so that the water level was located at 60cm from the focal spot; which also represents the focal spot to interventional reference plane distance for that fluoroscope. Results: PDDs for 60, 80, 100, and 120 kVp with 0 mm of copper filtration compared well to previously published data by Fetterly et al. [Med Phys, 28, 205 (2001)] for those beam qualities given differences in fluoroscopes, geometric orientation, type of ionization chamber, and the water tank used for data collection. PDDs for 60, 80, 100, and 120 kVp with copper filtration were obtained and are presented, which have not been previously investigated and published. Conclusion: The equipment and processes used to acquire the reported data were sound and compared well with previously published data for PDDs without copper filtration. PDD data for the fluoroscopic x-ray beams incorporating copper filtration can be used as reference data for estimating organ or soft tissue dose at depth involving similar beam qualities or for comparison with mathematical models.

  18. Image Enhancement Techniques for Cockpit Displays

    DTIC Science & Technology

    1974-12-01

    waveforms on the other hand have magnitudes of only 1, -1 and 0. This results in only addition and substraction for their computation. The following...PERFORMING ORG. REPORT NUMBER P74-530R/D0802 7. AUTHOR(&) 8. CONTRACT OR GRANT NUMBER(s) David J. Ketcham N00014-74-C-0313 Roger W. Lowe J. William Weber 9...Entered) Report No. P74-530R IMAGE ENHANCEMENT TECHNIQUES FOR COCKPIT DISPLAYS TECHNICAL REPORT David J. Ketcham Roger W. Lowe 3. William Weber Contract

  19. Update on cardiac imaging techniques 2014.

    PubMed

    Mahía-Casado, Patricia; García-Orta, Rocío; Gómez de Diego, José J; Barba-Cosials, Joaquín; Rodríguez-Palomares, José F; Aguadé-Bruix, Santiago

    2015-02-01

    In this article, we review the contributions of the most important imaging techniques used in cardiology, reported in 2014. Echocardiography remains the cornerstone for diagnosing and monitoring valvular heart disease, and there has been a continuing effort to improve quantification of this condition and obtain prognostic parameters for follow-up. The study of regional myocardial function is anchored in the diagnosis of subclinical ventricular dysfunction, and 3-dimensional transesophageal echocardiography has become the perfect ally in interventional procedures for structural heart disease. Cardiac magnetic resonance imaging and cardiac computed tomography are the focus of most publications on cardiac imaging in ischemic heart disease, reflecting their consolidated use in clinical practice. Nuclear medicine excels in the study of myocardial viability after interventional treatment of acute coronary syndromes and its performance is validated in the diagnosis of ischemic heart disease. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  20. Fast Imaging Technique for fMRI: Consecutive Multishot Echo Planar Imaging Accelerated with GRAPPA Technique.

    PubMed

    Kang, Daehun; Sung, Yul-Wan; Kang, Chang-Ki

    2015-01-01

    This study was to evaluate the proposed consecutive multishot echo planar imaging (cmsEPI) combined with a parallel imaging technique in terms of signal-to-noise ratio (SNR) and acceleration for a functional imaging study. We developed cmsEPI sequence using both consecutively acquired multishot EPI segments and variable flip angles to minimize the delay between segments and to maximize the SNR, respectively. We also combined cmsEPI with the generalized autocalibrating partially parallel acquisitions (GRAPPA) method. Temporal SNRs were measured at different acceleration factors and number of segments for functional sensitivity evaluation. We also examined the geometric distortions, which inherently occurred in EPI sequence. The practical acceleration factors, R = 2 or R = 3, of the proposed technique improved the temporal SNR by maximally 18% in phantom test and by averagely 8.2% in in vivo experiment, compared to cmsEPI without parallel imaging. The data collection time was decreased in inverse proportion to the acceleration factor as well. The improved temporal SNR resulted in better statistical power when evaluated on the functional response of the brain. In this study, we demonstrated that the combination of cmsEPI with the parallel imaging technique could provide the improved functional sensitivity for functional imaging study, compensating for the lower SNR by cmsEPI.

  1. Fast Imaging Technique for fMRI: Consecutive Multishot Echo Planar Imaging Accelerated with GRAPPA Technique

    PubMed Central

    Kang, Daehun; Sung, Yul-Wan; Kang, Chang-Ki

    2015-01-01

    This study was to evaluate the proposed consecutive multishot echo planar imaging (cmsEPI) combined with a parallel imaging technique in terms of signal-to-noise ratio (SNR) and acceleration for a functional imaging study. We developed cmsEPI sequence using both consecutively acquired multishot EPI segments and variable flip angles to minimize the delay between segments and to maximize the SNR, respectively. We also combined cmsEPI with the generalized autocalibrating partially parallel acquisitions (GRAPPA) method. Temporal SNRs were measured at different acceleration factors and number of segments for functional sensitivity evaluation. We also examined the geometric distortions, which inherently occurred in EPI sequence. The practical acceleration factors, R = 2 or R = 3, of the proposed technique improved the temporal SNR by maximally 18% in phantom test and by averagely 8.2% in in vivo experiment, compared to cmsEPI without parallel imaging. The data collection time was decreased in inverse proportion to the acceleration factor as well. The improved temporal SNR resulted in better statistical power when evaluated on the functional response of the brain. In this study, we demonstrated that the combination of cmsEPI with the parallel imaging technique could provide the improved functional sensitivity for functional imaging study, compensating for the lower SNR by cmsEPI. PMID:26413518

  2. Assessment of regularization techniques for electrocardiographic imaging

    PubMed Central

    Milanič, Matija; Jazbinšek, Vojko; MacLeod, Robert S.; Brooks, Dana H.; Hren, Rok

    2014-01-01

    A widely used approach to solving the inverse problem in electrocardiography involves computing potentials on the epicardium from measured electrocardiograms (ECGs) on the torso surface. The main challenge of solving this electrocardiographic imaging (ECGI) problem lies in its intrinsic ill-posedness. While many regularization techniques have been developed to control wild oscillations of the solution, the choice of proper regularization methods for obtaining clinically acceptable solutions is still a subject of ongoing research. However there has been little rigorous comparison across methods proposed by different groups. This study systematically compared various regularization techniques for solving the ECGI problem under a unified simulation framework, consisting of both 1) progressively more complex idealized source models (from single dipole to triplet of dipoles), and 2) an electrolytic human torso tank containing a live canine heart, with the cardiac source being modeled by potentials measured on a cylindrical cage placed around the heart. We tested 13 different regularization techniques to solve the inverse problem of recovering epicardial potentials, and found that non-quadratic methods (total variation algorithms) and first-order and second-order Tikhonov regularizations outperformed other methodologies and resulted in similar average reconstruction errors. PMID:24369741

  3. Endoscopic necrosectomy under fluoroscopic guidance – a single center experience

    PubMed Central

    Smoczyński, Marian; Jabłońska, Anna; Adrych, Krystian

    2015-01-01

    Introduction Our report presents a technique of necrotic tissue removal during transmural drainage of walled-off pancreatic necrosis (WOPN) that is an alternative to the one that has already been described in the literature. Aim To assess the effectiveness and safety of endoscopic necrosectomy performed during transmural drainage of symptomatic WOPN. Material and methods Within the years 2012–2013, 64 patients underwent endoscopic treatment of symptomatic WOPN in our center. Eight patients underwent endoscopic necrosectomy during transmural drainage. Fragments of necrotic tissues were removed from the collection's cavity under fluoroscopic guidance using a Dormia basket. The results and complications of treatment were compared retrospectively. Results Sixty-four patients with WOPN underwent transmural drainage under endoscopic ultrasonography (EUS) guidance. Eight patients (12.5%, 5 women and 3 men, mean age 57.25 years) were qualified for endoscopic necrosectomy. Transmural transgastric access was made in 7 patients and transduodenal access in 1 patient. Additional percutaneous drainage was used in 2 patients. Active drainage was continued for 24 days (11–44 days). The mean number of endoscopic procedures was 4.75 (3–9). The average number of necrosectomy procedures during drainage was 1.75 (1–4). Complications of endotherapy occurred in 2/8 (25%) patients, and they were not directly connected with necrosectomy. Therapeutic success after the end of active drainage was achieved in all patients. During a 6-month follow-up no recurrence of the collection was observed. Conclusions Endoscopic necrosectomy under fluoroscopic guidance is an effective and safe method of minimally invasive treatment in a selected group of patients with symptomatic WOPN. PMID:26240624

  4. The capability of fluoroscopic systems to determine differential Roentgen-ray absorption

    NASA Technical Reports Server (NTRS)

    Baily, N. A.; Crepeau, R. L.

    1975-01-01

    A clinical fluoroscopic unit used in conjunction with a TV image digitization system was investigated to determine its capability to evaluate differential absorption between two areas in the same field. Fractional contrasts and minimum detectability for air, several concentrations of Renografin-60, and aluminum were studied using phantoms of various thicknesses. Results showed that the videometric response, when treated as contrast, shows a linear response with absorber thickness up to considerable thicknesses.

  5. New imaging techniques in retinal vasculitis.

    PubMed

    Mesquida, Marina; Llorens, Víctor; Adán, Alfredo

    2017-09-20

    The term retinal vasculitis (RV) encompasses a heterogeneous group of sight-threatening conditions that are included in the intraocular inflammatory diseases that affect the posterior segment of the eye. Based on the nature of the inflammatory process, RV are classified into predominantly inflammatory or ischaemic (occlusive RV). The diagnosis is clinical and the aetiology can be infectious or non-infectious (immune-mediated). RV can be an isolated ocular syndrome or be associated with a systemic disease, of which they can represent the first manifestation. New retinal imaging techniques such as ultra-wide field fluorescein angiography and optical coherence tomography angiography will help us classify the RV and aid the diagnostic process, which can be challenging and require a multidisciplinary approach. Therefore, clinical knowledge of RV is essential for prompt diagnosis and to establish the appropriate treatment. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

  6. Techniques calm fear of imaging machine

    SciTech Connect

    Van Pelt, D.

    1990-04-02

    Magnetic resonance imaging has become a valuable tool in diagnosing diseases, and the imaging devices are now used as often as 2 million times a year in the United States. But as many as 10 percent of patients advised to undergo the procedure cannot because they become overwhelmed with claustrophobialike fear triggered by having to lie motionless in the machine's tunnel-like cylinder for about 45 minutes. To counteract this fear, several hospitals now practice various techniques to help reduce the feelings of confinement. One popular method is to give a patient special eyeglasses that allow him to look beyond his feet and see the tunnel opening. Other glasses use mirrors to direct the patient's vision out the back of the unit to large wilderness photographs or murals that simulate a sense of spaciousness. Even a basic item like a set of headphones that plays music can often distract a patient, and technicians frequently hold a patient's hand or foot during the procedure. Another trick is to invite family members and friends to remain with the patient during the scan to provide company and reassurance.

  7. Update on cardiac imaging techniques 2013.

    PubMed

    García-Orta, Rocío; Mahía-Casado, Patricia; Gómez de Diego, José J; Barba-Cosials, Joaquín; Rodriguez-Palomares, José F; Aguadé-Bruix, Santiago; Candell-Riera, Jaume

    2014-02-01

    Cardiac imaging is a cornerstone of diagnosis in heart conditions, and an essential tool for assessing prognosis and establishing treatment decisions. This year, echocardiography stands out as a guide in interventional procedures and in choosing the size of the prosthesis. It is also proving to be a valuable technique in low-flow, low-gradient aortic stenosis. Three-dimensional echocardiography is advancing our knowledge of cardiac anatomy and valvular measurements. The parameters indicating tissue deformation have predictive power in valve disease and in the follow-up of drug-induced cardiotoxicity. Single-photon emission computed tomography and positron emission tomography are proving useful in ischemic heart disease and in the diagnosis of cardiac inflammation and infections. The role of computed tomography has been strengthened in noninvasive coronary angiography, the emergency room management of chest pain, assessment of chronic occlusions, and morphologic study of coronary plaque. Cardiac magnetic resonance imaging remains the gold standard for tissue characterization in ischemic heart disease and cardiomyopathies, and is assuming a greater role in stress studies and in the assessment of myocardial viability. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  8. Low energy neutral atom imaging techniques

    SciTech Connect

    Funsten, H.O. McComas, D.J.; Scime, E.E.

    1993-01-01

    The potential scientific return from low energy neutral atom (LENA) imaging of the magnetosphere is extraordinary. The technical challenges of LENA detection include (1) removal of LENAs from the tremendous ambient UV without losing information of their incident trajectories, (2) quantification of their trajectories, and (3) obtaining high sensitivity measurements. Two techniques that have been proposed for this purpose are based on fundamentally different atomic interaction mechanisms between LENAs and a solid: LENA transmission through an ultrathin foil and LENA reflection from a solid surface. Both of these methods provide LENA ionization (for subsequent removal from the UV by electrostatic deflection) and secondary electron emission (for start pulse generation for time-of-flight and/or coincidence). We present a comparative study of the transmission and reflection techniques based on differences in atomic interactions with solids and surfaces. We show that transmission methods yield an order of magnitude greater secondary electron emission than reflection methods. Transmission methods are shown to be sufficient for LENA energies of approximately 1 keV to greater than 30 keV. Reflection methods using low work function surfaces could be employed for LENA ionization for energies less than several keV.

  9. Mathematical Morphology Techniques For Image Processing Applications In Biomedical Imaging

    NASA Astrophysics Data System (ADS)

    Bartoo, Grace T.; Kim, Yongmin; Haralick, Robert M.; Nochlin, David; Sumi, Shuzo M.

    1988-06-01

    Mathematical morphology operations allow object identification based on shape and are useful for grouping a cluster of small objects into one object. Because of these capabilities, we have implemented and evaluated this technique for our study of Alzheimer's disease. The microscopic hallmark of Alzheimer's disease is the presence of brain lesions known as neurofibrillary tangles and senile plaques. These lesions have distinct shapes compared to normal brain tissue. Neurofibrillary tangles appear as flame-shaped structures, whereas senile plaques appear as circular clusters of small objects. In order to quantitatively analyze the distribution of these lesions, we have developed and applied the tools of mathematical morphology on the Pixar Image Computer. As a preliminary test of the accuracy of the automatic detection algorithm, a study comparing computer and human detection of senile plaques was performed by evaluating 50 images from 5 different patients. The results of this comparison demonstrates that the computer counts correlate very well with the human counts (correlation coefficient = .81). Now that the basic algorithm has been shown to work, optimization of the software will be performed to improve its speed. Also future improvements such as local adaptive thresholding will be made to the image analysis routine to further improve the systems accuracy.

  10. Digital Subtraction Fluoroscopic System With Tandem Video Processing Units

    NASA Astrophysics Data System (ADS)

    Gould, Robert G.; Lipton, Martin J.; Mengers, Paul; Dahlberg, Roger

    1981-07-01

    A real-time digital fluoroscopic system utilizing two video processing units (Quantex) in tandem to produce continuous subtraction images of peripheral and internal vessels following intravenous contrast media injection has been inves-tigated. The first processor subtracts a mask image consisting of an exponentially weighted moving average of N1 frames (N1 = 2k where k = 0.7) from each incoming video frame, divides by N1, and outputs the resulting difference image to the second processor. The second unit continuously averages N2 incoming frames (N2 = 2k) and outputs to a video monitor and analog disc recorder. The contrast of the subtracted images can be manipulated by changing gain or by a non-linear output transform. After initial equipment adjustments, a subtraction sequence can be produced without operator interaction with the processors. Alternatively, the operator can freeze the mask and/or the subtracted output image at any time during the sequence. Raw data is preserved on a wide band video tape recorder permitting retrospective viewing of an injection sequence with different processor settings. The advantage of the tandem arrangement is that it has great flexibility in varying the duration and the time of both the mask and injection images thereby minimizing problems of registration between them. In addition, image noise is reduced by compiling video frames rather than by using a large radiation dose for a single frame, which requires a wide dynamic range video camera riot commonly available in diagnostic x-ray equipment. High quality subtraction images of arteries have been obtained in 15 anesthetized dogs using relatively low exposure rates (10-12 μR/video frame) modest volumes of contrast medium (0.5-1 ml/kg), and low injection flow rates (6-10 ml/sec). The results/ achieved so far suggest that this system has direct clinical applications.

  11. A small, battery-operated fluoroscopic system - Lixiscope with X-ray generator

    NASA Technical Reports Server (NTRS)

    Yin, L. I.; Trombka, J. I.; Ruitberg, A. P.; Seltzer, S. M.

    1983-01-01

    A small, battery-operated X-ray generator has been developed to be used as part of a small-format fluoroscopic system, the Lixiscope (Low Intensity X-ray Imaging Scope). The X-ray generator consists of a grounded rod-anode X-ray tube with a 0.2 mm focal spot and a specially designed, battery-operated, 0 to -80 kV high-voltge supply. Total power consumption is about 10 W. The fine focal spot, in conjunction with the continuously variable X-ray intensity and spectral distribution, helps to extend both the versatility and the performance of the Lixiscope toward a much wider range of terrestrial and spacecraft applications. The complete fluoroscopic system is described, and some examples of possible applications are shown.

  12. Fluoroscopic tracking of multiple implanted fiducial markers using multiple object tracking.

    PubMed

    Tang, Xiaoli; Sharp, Greg C; Jiang, Steve B

    2007-07-21

    When treating mobile tumors using techniques such as beam gating or beam tracking, precise localization of tumor position is required, which is often realized by fluoroscopically tracking implanted fiducial markers. Multiple markers placed inside or near a tumor are often preferred to a single marker for the sake of accuracy. In this work, we propose a marker tracking system that can track multiple markers simultaneously, without confusing them, and that is also robust enough to continue tracking even when the markers are moving behind bony anatomy. The integrated radiotherapy imaging system (IRIS), developed at the Massachusetts General Hospital (MGH), was used to take fluoroscopy videos for marker tracking. The tracking system integrates marker detection with a multiple object tracking process, inspired by the multiple hypothesis marker tracking (MHT) process. It also utilizes breathing pattern information to help tracking. Four criteria are used to identify tracking failure, and when tracking failure occurs, the system can immediately inform the user. (In the clinical environment, the system would immediately disable the treatment beam.) In this paper, two liver patients with implanted fiducial markers were studied, and the studies were performed retrospectively to assess the effectiveness of the new tracking system. For both patients, LAT and AP fluoroscopic videos were studied. In order to better test the proposed tracking system, artificial markers were added around the real markers to disturb the tracking of the real markers. The performance of the proposed system was compared to that of a conventional tracking system (one that did not use multiple object tracking). The performance of the new system was also investigated with and without consideration of the breathing pattern information. We found that the conventional tracking system can easily miss tracking markers in the presence of artificial markers, and it cannot detect the tracking failures. On the

  13. Fluoroscopic tracking of multiple implanted fiducial markers using multiple object tracking

    NASA Astrophysics Data System (ADS)

    Tang, Xiaoli; Sharp, Greg C.; Jiang, Steve B.

    2007-07-01

    When treating mobile tumors using techniques such as beam gating or beam tracking, precise localization of tumor position is required, which is often realized by fluoroscopically tracking implanted fiducial markers. Multiple markers placed inside or near a tumor are often preferred to a single marker for the sake of accuracy. In this work, we propose a marker tracking system that can track multiple markers simultaneously, without confusing them, and that is also robust enough to continue tracking even when the markers are moving behind bony anatomy. The integrated radiotherapy imaging system (IRIS), developed at the Massachusetts General Hospital (MGH), was used to take fluoroscopy videos for marker tracking. The tracking system integrates marker detection with a multiple object tracking process, inspired by the multiple hypothesis marker tracking (MHT) process. It also utilizes breathing pattern information to help tracking. Four criteria are used to identify tracking failure, and when tracking failure occurs, the system can immediately inform the user. (In the clinical environment, the system would immediately disable the treatment beam.) In this paper, two liver patients with implanted fiducial markers were studied, and the studies were performed retrospectively to assess the effectiveness of the new tracking system. For both patients, LAT and AP fluoroscopic videos were studied. In order to better test the proposed tracking system, artificial markers were added around the real markers to disturb the tracking of the real markers. The performance of the proposed system was compared to that of a conventional tracking system (one that did not use multiple object tracking). The performance of the new system was also investigated with and without consideration of the breathing pattern information. We found that the conventional tracking system can easily miss tracking markers in the presence of artificial markers, and it cannot detect the tracking failures. On the

  14. Measuring techniques in induced polarisation imaging

    NASA Astrophysics Data System (ADS)

    Dahlin, Torleif; Leroux, Virginie; Nissen, Johan

    2002-06-01

    Multi-electrode geoelectrical imaging has become very popular and is used for many different purposes. For some of these, the inclusion of IP data would be desirable as it would allow the interpreter to distinguish between, e.g. sand formations with saltwater infiltration and clay formations or help delineate landfills. However, present-day IP measuring techniques require the use of nonpolarisable potential electrodes and special wire layout and are thus cumbersome and expensive. In this paper, we suggest making IP measurements with multi-electrode cables and just one set of steel electrodes. The polarisation potentials on the potential electrodes are corrected for by subtracting the polarisation potential measured when no primary current and no IP signal are present. Test measurements indicate that the polarisation potentials vary slowly and that the correction procedure is feasible. At two sites in southern Sweden, we have compared measurements with only stainless steel electrodes and measurements with both stainless steel and Pb-PbCl nonpolarisable electrodes using one or two sets of multicore cables, respectively. Almost no difference between the two data sets was observed. At one site, the charge-up effect on the potential electrodes was not important, while at the other site, the correction procedure was crucial. Though only two sites have been studied so far, it seems that time-domain IP imaging measurements can be taken with only steel electrodes and ordinary multicore cables. Coupling in the multicore cables has not presented any problems at the investigated sites where grounding resistances were moderate, making the coupling effect small. High grounding resistance sites have not yet been investigated.

  15. A Literature Review on Image Encryption Techniques

    NASA Astrophysics Data System (ADS)

    Khan, Majid; Shah, Tariq

    2014-12-01

    Image encryption plays a paramount part to guarantee classified transmission and capacity of image over web. Then again, a real-time image encryption confronts a more noteworthy test because of vast measure of information included. This paper exhibits an audit on image encryption in spatial, frequency and hybrid domains with both full encryption and selective encryption strategy.

  16. Robust Fluoroscopic Tracking of Fiducial Markers: Exploiting the Spatial Constraints

    PubMed Central

    Li, Rui; Sharp, Gregory

    2013-01-01

    Two new fluoroscopic fiducial tracking methods that exploit the spatial relationship among the multiple implanted fiducial to achieve fast, accurate and robust tracking are proposed in this paper. The spatial relationship between multiple implanted markers are modeled as Gaussian distributions of their pairwise distances over time. The means and standard deviations of these distances are learned from training sequences, and pairwise distances that deviate from these learned distributions are assigned a low spatial matching score. The spatial constraints are incorporated in two different algorithms: a stochastic tracking method and a detection based method. In the stochastic method, hypotheses of the “true” fiducial position are sampled from a pre-trained respiration motion model. Each hypothesis is assigned an importance value based on image matching score and spatial matching score. Learning the parameters of the motion model is needed in addition to the learning the distribution parameters of the pairwise distances in the proposed stochastic tracking approach. In the detection based method, a set of possible marker locations are identified by using a template matching based fiducial detector. The best location is obtained by optimizing the image matching score and spatial matching score through non-serial dynamic programming. In this detection based approach, there is no need to learn the respiration motion model. The two proposed algorithms are compared with a recent work using multiple hypothesis tracking algorithm which is denoted by MHT[19]. Phantom experiments were performed using fluoroscopic videos captured with known motion relative to an anthropomorphic phantom. The patient experiments were performed using a retrospective study of 16 fluoroscopic videos of liver cancer patients with implanted fiducials. For the motion phantom data sets, the detection based approach has the smallest tracking error (μerr: 0.78 – 1.74 mm, σerr: 0.39 – 1.16 mm) for

  17. Robust fluoroscopic tracking of fiducial markers: exploiting the spatial constraints

    NASA Astrophysics Data System (ADS)

    Li, Rui; Sharp, Gregory

    2013-03-01

    Two new fluoroscopic fiducial tracking methods that exploit the spatial relationship among the multiple implanted fiducial to achieve fast, accurate and robust tracking are proposed in this paper. The spatial relationship between multiple implanted markers are modeled as Gaussian distributions of their pairwise distances over time. The means and standard deviations of these distances are learned from training sequences, and pairwise distances that deviate from these learned distributions are assigned a low spatial matching score. The spatial constraints are incorporated in two different algorithms: a stochastic tracking method and a detection based method. In the stochastic method, hypotheses of the ‘true’ fiducial position are sampled from a pre-trained respiration motion model. Each hypothesis is assigned an importance value based on image matching score and spatial matching score. Learning the parameters of the motion model is needed in addition to learning the distribution parameters of the pairwise distances in the proposed stochastic tracking approach. In the detection based method, a set of possible marker locations are identified by using a template matching based fiducial detector. The best location is obtained by optimizing the image matching score and spatial matching score through non-serial dynamic programming. In this detection based approach, there is no need to learn the respiration motion model. The two proposed algorithms are compared with a recent work using a multiple hypothesis tracking (MHT) algorithm which is denoted by MHT, Tang et al (2007 Phys. Med. Biol. 52 4081-98). Phantom experiments were performed using fluoroscopic videos captured with known motion relative to an anthropomorphic phantom. The patient experiments were performed using a retrospective study of 16 fluoroscopic videos of liver cancer patients with implanted fiducials. For the motion phantom data sets, the detection based approach has the smallest tracking error (

  18. Improved accuracy of markerless motion tracking on bone suppression images: preliminary study for image-guided radiation therapy (IGRT)

    NASA Astrophysics Data System (ADS)

    Tanaka, Rie; Sanada, Shigeru; Sakuta, Keita; Kawashima, Hiroki

    2015-05-01

    The bone suppression technique based on advanced image processing can suppress the conspicuity of bones on chest radiographs, creating soft tissue images obtained by the dual-energy subtraction technique. This study was performed to evaluate the usefulness of bone suppression image processing in image-guided radiation therapy. We demonstrated the improved accuracy of markerless motion tracking on bone suppression images. Chest fluoroscopic images of nine patients with lung nodules during respiration were obtained using a flat-panel detector system (120 kV, 0.1 mAs/pulse, 5 fps). Commercial bone suppression image processing software was applied to the fluoroscopic images to create corresponding bone suppression images. Regions of interest were manually located on lung nodules and automatic target tracking was conducted based on the template matching technique. To evaluate the accuracy of target tracking, the maximum tracking error in the resulting images was compared with that of conventional fluoroscopic images. The tracking errors were decreased by half in eight of nine cases. The average maximum tracking errors in bone suppression and conventional fluoroscopic images were 1.3   ±   1.0 and 3.3   ±   3.3 mm, respectively. The bone suppression technique was especially effective in the lower lung area where pulmonary vessels, bronchi, and ribs showed complex movements. The bone suppression technique improved tracking accuracy without special equipment and implantation of fiducial markers, and with only additional small dose to the patient. Bone suppression fluoroscopy is a potential measure for respiratory displacement of the target. This paper was presented at RSNA 2013 and was carried out at Kanazawa University, JAPAN.

  19. Fluoroscopic-guided lumbar puncture: fluoroscopic time and implications of body mass index--a baseline study.

    PubMed

    Boddu, S R; Corey, A; Peterson, R; Saindane, A M; Hudgins, P A; Chen, Z; Wang, X; Applegate, K E

    2014-08-01

    Fluoroscopic-guided lumbar puncture is an effective alternative to bedside lumbar puncture in challenging patients. However, no published guidelines are available for an acceptable range of fluoroscopic time for this procedure. The purpose of this study was to set department benchmark fluoroscopic times for lumbar puncture, accounting for body mass index in our patient population. We identified and reviewed all patients who underwent fluoroscopic-guided lumbar puncture at 4 hospitals during a 2-year period (July 2011 to June 2013). Data collection included patient information (demographics, body mass index, history of prior lumbar surgery and/or lumbar hardware, scoliosis); procedure details (fluoroscopic time, level of access, approach, needle gauge and length); level of operator experience; and hospital site. A generalized linear model was used to test whether body mass index influenced fluoroscopic time while controlling other factors. Five hundred eighty-four patients (mean age, 47.8 ± 16.2 years; range, 16-92 years; 33% male) had successful fluoroscopic-guided lumbar puncture s. Mean body mass index and fluoroscopic time were higher in female patients (34.4 ± 9.9 kg/m(2) and 1.07 minutes; 95% CI, 0.95-1.20) than in male patients (29.2 ± 7.3 kg/m(2) and 0.91 minutes; 95% CI, 0.79-1.03). Body mass index (P = .001), hospital site (P < .001), and level of experience (P = .03) were factors significantly affecting fluoroscopic time on multivariate analysis. Benchmark fluoroscopic times in minutes were the following: 0.48 (95% CI, 0.40-0.56) for normal, 0.61 for overweight (95% CI, 0.52-0.71), 0.63(95% CI, 0.58-0.73) for obese, and 0.86 (95% CI, 0.74-1.01) in extremely obese body mass index categories. In patients undergoing fluoroscopic-guided lumbar punctures, fluoroscopy time increased with body mass index We established benchmark fluoroscopic-guided lumbar puncture time ranges as related to body mass index in our patient population. © 2014 by American Journal

  20. Dilemmas in imaging for peri-acetabular osteotomy: the influence of patient position and imaging technique on the radiological features of hip dysplasia.

    PubMed

    Kosuge, D; Cordier, T; Solomon, L B; Howie, D W

    2014-09-01

    Peri-acetabular osteotomy is an established surgical treatment for symptomatic acetabular dysplasia in young adults. An anteroposterior radiograph of the pelvis is commonly used to assess the extent of dysplasia as well as to assess post-operative correction. Radiological prognostic factors include the lateral centre-edge angle, acetabular index, extrusion index and the acetabular version. Standing causes a change in the pelvis tilt which can alter certain radiological measurements relative to the supine position. This article discusses the radiological indices used to assess dysplasia and reviews the effects of patient positioning on these indices with a focus on assessment for a peri-acetabular osteotomy. Intra-operatively, fluoroscopy is commonly used and the implications of using fluoroscopy as a modality to assess the various radiological indices along with the effects of using an anteroposterior or posteroanterior fluoroscopic view are examined. Each of these techniques gives rise to a slightly different image of the pelvis as the final image is sensitive to the position of the pelvis and the projection of the x-ray beam.

  1. A Review of Imaging Techniques for Plant Phenotyping

    PubMed Central

    Li, Lei; Zhang, Qin; Huang, Danfeng

    2014-01-01

    Given the rapid development of plant genomic technologies, a lack of access to plant phenotyping capabilities limits our ability to dissect the genetics of quantitative traits. Effective, high-throughput phenotyping platforms have recently been developed to solve this problem. In high-throughput phenotyping platforms, a variety of imaging methodologies are being used to collect data for quantitative studies of complex traits related to the growth, yield and adaptation to biotic or abiotic stress (disease, insects, drought and salinity). These imaging techniques include visible imaging (machine vision), imaging spectroscopy (multispectral and hyperspectral remote sensing), thermal infrared imaging, fluorescence imaging, 3D imaging and tomographic imaging (MRT, PET and CT). This paper presents a brief review on these imaging techniques and their applications in plant phenotyping. The features used to apply these imaging techniques to plant phenotyping are described and discussed in this review. PMID:25347588

  2. A review of imaging techniques for plant phenotyping.

    PubMed

    Li, Lei; Zhang, Qin; Huang, Danfeng

    2014-10-24

    Given the rapid development of plant genomic technologies, a lack of access to plant phenotyping capabilities limits our ability to dissect the genetics of quantitative traits. Effective, high-throughput phenotyping platforms have recently been developed to solve this problem. In high-throughput phenotyping platforms, a variety of imaging methodologies are being used to collect data for quantitative studies of complex traits related to the growth, yield and adaptation to biotic or abiotic stress (disease, insects, drought and salinity). These imaging techniques include visible imaging (machine vision), imaging spectroscopy (multispectral and hyperspectral remote sensing), thermal infrared imaging, fluorescence imaging, 3D imaging and tomographic imaging (MRT, PET and CT). This paper presents a brief review on these imaging techniques and their applications in plant phenotyping. The features used to apply these imaging techniques to plant phenotyping are described and discussed in this review.

  3. Feature-based respiratory motion tracking in native fluoroscopic sequences for dynamic roadmaps during minimally invasive procedures in the thorax and abdomen

    NASA Astrophysics Data System (ADS)

    Wagner, Martin G.; Laeseke, Paul F.; Schubert, Tilman; Slagowski, Jordan M.; Speidel, Michael A.; Mistretta, Charles A.

    2017-03-01

    Fluoroscopic image guidance for minimally invasive procedures in the thorax and abdomen suffers from respiratory and cardiac motion, which can cause severe subtraction artifacts and inaccurate image guidance. This work proposes novel techniques for respiratory motion tracking in native fluoroscopic images as well as a model based estimation of vessel deformation. This would allow compensation for respiratory motion during the procedure and therefore simplify the workflow for minimally invasive procedures such as liver embolization. The method first establishes dynamic motion models for both the contrast-enhanced vasculature and curvilinear background features based on a native (non-contrast) and a contrast-enhanced image sequence acquired prior to device manipulation, under free breathing conditions. The model of vascular motion is generated by applying the diffeomorphic demons algorithm to an automatic segmentation of the subtraction sequence. The model of curvilinear background features is based on feature tracking in the native sequence. The two models establish the relationship between the respiratory state, which is inferred from curvilinear background features, and the vascular morphology during that same respiratory state. During subsequent fluoroscopy, curvilinear feature detection is applied to determine the appropriate vessel mask to display. The result is a dynamic motioncompensated vessel mask superimposed on the fluoroscopic image. Quantitative evaluation of the proposed methods was performed using a digital 4D CT-phantom (XCAT), which provides realistic human anatomy including sophisticated respiratory and cardiac motion models. Four groups of datasets were generated, where different parameters (cycle length, maximum diaphragm motion and maximum chest expansion) were modified within each image sequence. Each group contains 4 datasets consisting of the initial native and contrast enhanced sequences as well as a sequence, where the respiratory motion is

  4. Imaging techniques: MRI illuminated by γ-rays

    NASA Astrophysics Data System (ADS)

    Bowtell, Richard

    2016-09-01

    A technique that combines magnetic resonance with nuclear medicine has been used to image the distribution of a radioactive tracer, potentially opening up a powerful and innovative approach to medical imaging. See Letter p.652

  5. [Tomographic ultrasound imaging (TUI)--technique and methodological study].

    PubMed

    Markov, D

    2008-01-01

    We present a new form of data image processing obtained through three-dimensional scanning named tomographic ultrasound imaging (TUI) and discuss its technique and clinical implications in obstetrics and gynecology.

  6. Functional Imaging and Related Techniques: An Introduction for Rehabilitation Researchers

    PubMed Central

    Crosson, Bruce; Ford, Anastasia; McGregor, Keith M.; Meinzer, Marcus; Cheshkov, Sergey; Li, Xiufeng; Walker-Batson, Delaina; Briggs, Richard W.

    2010-01-01

    Functional neuroimaging and related neuroimaging techniques are becoming important tools for rehabilitation research. Functional neuroimaging techniques can be used to determine the effects of brain injury or disease on brain systems related to cognition and behavior and to determine how rehabilitation changes brain systems. These techniques include: functional magnetic resonance imaging (fMRI), positron emission tomography (PET), electroencephalography (EEG), magnetoencephalography (MEG), near infrared spectroscopy (NIRS), and transcranial magnetic stimulation (TMS). Related diffusion weighted magnetic resonance imaging techniques (DWI), including diffusion tensor imaging (DTI) and high angular resolution diffusion imaging (HARDI), can quantify white matter integrity. With the proliferation of these imaging techniques in rehabilitation research, it is critical that rehabilitation researchers, as well as consumers of rehabilitation research, become familiar with neuroimaging techniques, what they can offer, and their strengths and weaknesses The purpose to this review is to provide such an introduction to these neuroimaging techniques. PMID:20593321

  7. Measuring radiation dose to patients undergoing fluoroscopically-guided interventions

    NASA Astrophysics Data System (ADS)

    Lubis, L. E.; Badawy, M. K.

    2016-03-01

    The increasing prevalence and complexity of fluoroscopically guided interventions (FGI) raises concern regarding radiation dose to patients subjected to the procedure. Despite current evidence showing the risk to patients from the deterministic effects of radiation (e.g. skin burns), radiation induced injuries remain commonplace. This review aims to increase the awareness surrounding radiation dose measurement for patients undergoing FGI. A review of the literature was conducted alongside previous researches from the authors’ department. Studies pertaining to patient dose measurement, its formalism along with current advances and present challenges were reviewed. Current patient monitoring techniques (using available radiation dosimeters), as well as the inadequacy of accepting displayed dose as patient radiation dose is discussed. Furthermore, advances in real-time patient radiation dose estimation during FGI are considered. Patient dosimetry in FGI, particularly in real time, remains an ongoing challenge. The increasing occurrence and sophistication of these procedures calls for further advances in the field of patient radiation dose monitoring. Improved measuring techniques will aid clinicians in better predicting and managing radiation induced injury following FGI, thus improving patient care.

  8. Fluoroscopically Guided Balloon Dilation for Postintubation Tracheal Stenosis

    SciTech Connect

    Lee, Woong Hee; Kim, Jin Hyoung Park, Jung-Hun

    2013-10-15

    Purpose: Little was known about the safety and long-term efficacy of fluoroscopically guided balloon dilation for postintubation tracheal stenosis. The purpose of this study was to evaluate the safety and long-term efficacy of fluoroscopically guided balloon dilation in patients with postintubation tracheal stenosis. Methods: From February 2000 to November 2010, 14 patients underwent fluoroscopically guided balloon dilation for postintubation tracheal stenosis. Technical success, clinical success, and complications were evaluated. Patients were followed up for recurrent symptoms. Results: In all patients, fluoroscopically guided balloon dilation was technically and clinically successful with no major complications. Following the initial procedure, six patients (43 %) remained asymptomatic during a follow-up period. Obstructive symptoms recurred in eight patients (57 %) within 6 months (mean, 1.7 months), who were treated with repeat balloon dilation (n = 4) and other therapies. Of the four patients who underwent repeat balloon dilation, three became asymptomatic. One patient became asymptomatic after a third balloon dilation. On long-term (mean, 74 months) follow-up, 71 % of patients experienced relief of symptoms following fluoroscopically guided balloon dilation. Conclusions: Fluoroscopically guided balloon dilation may be safe, is easy to perform, and resulted in effective treatment in patients with postintubation tracheal stenosis.

  9. A spatio-temporal detective quantum efficiency and its application to fluoroscopic systems.

    PubMed

    Friedman, S N; Cunningham, I A

    2010-11-01

    Fluoroscopic x-ray imaging systems are used extensively in spatio-temporal detection tasks and require a spatio-temporal description of system performance. No accepted metric exists that describes spatio-temporal fluoroscopic performance. The detective quantum efficiency (DQE) is a metric widely used in radiography to quantify system performance and as a surrogate measure of patient "dose efficiency". It has been applied previously to fluoroscopic systems with the introduction of a temporal correction factor. However, the use of a temporally-corrected DQE does not provide system temporal information and it is only valid under specific conditions, many of which are not likely to be satisfied by suboptimal systems. The authors propose a spatio-temporal DQE that describes performance in both space and time and is applicable to all spatio-temporal quantum-based imaging systems. The authors define a spatio-temporal DQE (two spatial-frequency axes and one temporal-frequency axis) in terms of a small-signal spatio-temporal modulation transfer function (MTF) and spatio-temporal noise power spectrum (NPS). Measurements were made on an x-ray image intensifier-based bench-top system using continuous fluoroscopy with an RQA-5 beam at 3.9 microR/frame and hardened 50 kVp beam (0.8 mm Cu filtration added) at 1.9 microR/frame. A zero-frequency DQE value of 0.64 was measured under both conditions. Nonideal performance was noted at both larger spatial and temporal frequencies; DQE values decreased by approximately 50% at the cutoff temporal frequency of 15 Hz. The spatio-temporal DQE enables measurements of decreased temporal system performance at larger temporal frequencies analogous to previous measurements of decreased (spatial) performance. This marks the first time that system performance and dose efficiency in both space and time have been measured on a fluoroscopic system using DQE and is the first step toward the generalized use of DQE on clinical fluoroscopic systems.

  10. A spatio-temporal detective quantum efficiency and its application to fluoroscopic systems

    SciTech Connect

    Friedman, S. N.; Cunningham, I. A.

    2010-11-15

    Purpose: Fluoroscopic x-ray imaging systems are used extensively in spatio-temporal detection tasks and require a spatio-temporal description of system performance. No accepted metric exists that describes spatio-temporal fluoroscopic performance. The detective quantum efficiency (DQE) is a metric widely used in radiography to quantify system performance and as a surrogate measure of patient ''dose efficiency.'' It has been applied previously to fluoroscopic systems with the introduction of a temporal correction factor. However, the use of a temporally-corrected DQE does not provide system temporal information and it is only valid under specific conditions, many of which are not likely to be satisfied by suboptimal systems. The authors propose a spatio-temporal DQE that describes performance in both space and time and is applicable to all spatio-temporal quantum-based imaging systems. Methods: The authors define a spatio-temporal DQE (two spatial-frequency axes and one temporal-frequency axis) in terms of a small-signal spatio-temporal modulation transfer function (MTF) and spatio-temporal noise power spectrum (NPS). Measurements were made on an x-ray image intensifier-based bench-top system using continuous fluoroscopy with an RQA-5 beam at 3.9 {mu}R/frame and hardened 50 kVp beam (0.8 mm Cu filtration added) at 1.9 {mu}R/frame. Results: A zero-frequency DQE value of 0.64 was measured under both conditions. Nonideal performance was noted at both larger spatial and temporal frequencies; DQE values decreased by {approx}50% at the cutoff temporal frequency of 15 Hz. Conclusions: The spatio-temporal DQE enables measurements of decreased temporal system performance at larger temporal frequencies analogous to previous measurements of decreased (spatial) performance. This marks the first time that system performance and dose efficiency in both space and time have been measured on a fluoroscopic system using DQE and is the first step toward the generalized use of DQE on

  11. Imaging fault zones using 3D seismic image processing techniques

    NASA Astrophysics Data System (ADS)

    Iacopini, David; Butler, Rob; Purves, Steve

    2013-04-01

    Significant advances in structural analysis of deep water structure, salt tectonic and extensional rift basin come from the descriptions of fault system geometries imaged in 3D seismic data. However, even where seismic data are excellent, in most cases the trajectory of thrust faults is highly conjectural and still significant uncertainty exists as to the patterns of deformation that develop between the main faults segments, and even of the fault architectures themselves. Moreover structural interpretations that conventionally define faults by breaks and apparent offsets of seismic reflectors are commonly conditioned by a narrow range of theoretical models of fault behavior. For example, almost all interpretations of thrust geometries on seismic data rely on theoretical "end-member" behaviors where concepts as strain localization or multilayer mechanics are simply avoided. Yet analogue outcrop studies confirm that such descriptions are commonly unsatisfactory and incomplete. In order to fill these gaps and improve the 3D visualization of deformation in the subsurface, seismic attribute methods are developed here in conjunction with conventional mapping of reflector amplitudes (Marfurt & Chopra, 2007)). These signal processing techniques recently developed and applied especially by the oil industry use variations in the amplitude and phase of the seismic wavelet. These seismic attributes improve the signal interpretation and are calculated and applied to the entire 3D seismic dataset. In this contribution we will show 3D seismic examples of fault structures from gravity-driven deep-water thrust structures and extensional basin systems to indicate how 3D seismic image processing methods can not only build better the geometrical interpretations of the faults but also begin to map both strain and damage through amplitude/phase properties of the seismic signal. This is done by quantifying and delineating the short-range anomalies on the intensity of reflector amplitudes

  12. Real-Time Verification of a High-Dose-Rate Iridium 192 Source Position Using a Modified C-Arm Fluoroscope.

    PubMed

    Nose, Takayuki; Chatani, Masashi; Otani, Yuki; Teshima, Teruki; Kumita, Shinichirou

    2017-03-15

    High-dose-rate (HDR) brachytherapy misdeliveries can occur at any institution, and they can cause disastrous results. Even a patient's death has been reported. Misdeliveries could be avoided with real-time verification methods. In 1996, we developed a modified C-arm fluoroscopic verification of an HDR Iridium 192 source position prevent these misdeliveries. This method provided excellent image quality sufficient to detect errors, and it has been in clinical use at our institutions for 20 years. The purpose of the current study is to introduce the mechanisms and validity of our straightforward C-arm fluoroscopic verification method. Conventional X-ray fluoroscopic images are degraded by spurious signals and quantum noise from Iridium 192 photons, which make source verification impractical. To improve image quality, we quadrupled the C-arm fluoroscopic X-ray dose per pulse. The pulse rate was reduced by a factor of 4 to keep the average exposure compliant with Japanese medical regulations. The images were then displayed with quarter-frame rates. Sufficient quality was obtained to enable observation of the source position relative to both the applicators and the anatomy. With this method, 2 errors were detected among 2031 treatment sessions for 370 patients within a 6-year period. With the use of a modified C-arm fluoroscopic verification method, treatment errors that were otherwise overlooked were detected in real time. This method should be given consideration for widespread use. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. In Vivo Imaging Techniques: A New Era for Histochemical Analysis

    PubMed Central

    Busato, A.; Feruglio, P. Fumene; Parnigotto, P.P.; Marzola, P.; Sbarbati, A.

    2016-01-01

    In vivo imaging techniques can be integrated with classical histochemistry to create an actual histochemistry of water. In particular, Magnetic Resonance Imaging (MRI), an imaging technique primarily used as diagnostic tool in clinical/preclinical research, has excellent anatomical resolution, unlimited penetration depth and intrinsic soft tissue contrast. Thanks to the technological development, MRI is not only capable to provide morphological information but also and more interestingly functional, biophysical and molecular. In this paper we describe the main features of several advanced imaging techniques, such as MRI microscopy, Magnetic Resonance Spectroscopy, functional MRI, Diffusion Tensor Imaging and MRI with contrast agent as a useful support to classical histochemistry. PMID:28076937

  14. Imaging techniques in signal transduction IHC.

    PubMed

    Sedgewick, Jerry

    2011-01-01

    Augmentation of digital images is almost always a necessity in order to obtain a reproduction that matches the appearance of the original. However, that augmentation can mislead if it is done incorrectly and not within reasonable limits. When procedures are in place for ensuring that originals are archived, and image manipulation steps are reported, scientists not only follow good laboratory practices, but also avoid ethical issues associated with postprocessing and protect their labs from any future allegations of scientific misconduct. Also, when procedures are in place for correct acquisition of images, the extent of postprocessing is minimized or eliminated. These procedures include color balancing (for brighfield images), keeping tonal values within the dynamic range of the detector, frame averaging to eliminate noise (typically in fluorescence imaging), use of the highest bit depth when a choice is available, flatfield correction, and archiving of the image in a nonlossy format (not JPEG).When postprocessing is necessary, the commonly used applications for correction include Photoshop, and ImageJ, but a free program (GIMP) can also be used. Corrections to images include scaling the bit depth to higher and lower ranges, removing color casts from brightfield images, setting brightness and contrast, reducing color noise, reducing "grainy" noise, conversion of pure colors to grayscale, conversion of grayscale to colors typically used in fluorescence imaging, correction of uneven illumination and flatfield correction, blending color images (fluorescence), and extending the depth of focus. These corrections are explained in step-by-step procedures in the chapter that follows.

  15. A hybrid technique for medical image segmentation.

    PubMed

    Nyma, Alamgir; Kang, Myeongsu; Kwon, Yung-Keun; Kim, Cheol-Hong; Kim, Jong-Myon

    2012-01-01

    Medical image segmentation is an essential and challenging aspect in computer-aided diagnosis and also in pattern recognition research. This paper proposes a hybrid method for magnetic resonance (MR) image segmentation. We first remove impulsive noise inherent in MR images by utilizing a vector median filter. Subsequently, Otsu thresholding is used as an initial coarse segmentation method that finds the homogeneous regions of the input image. Finally, an enhanced suppressed fuzzy c-means is used to partition brain MR images into multiple segments, which employs an optimal suppression factor for the perfect clustering in the given data set. To evaluate the robustness of the proposed approach in noisy environment, we add different types of noise and different amount of noise to T1-weighted brain MR images. Experimental results show that the proposed algorithm outperforms other FCM based algorithms in terms of segmentation accuracy for both noise-free and noise-inserted MR images.

  16. An image compression technique for use on token ring networks

    NASA Astrophysics Data System (ADS)

    Gorjala, B.; Sayood, Khalid; Meempat, G.

    1992-12-01

    A low complexity technique for compression of images for transmission over local area networks is presented. The technique uses the synchronous traffic as a side channel for improving the performance of an adaptive differential pulse code modulation (ADPCM) based coder.

  17. An image compression technique for use on token ring networks

    NASA Technical Reports Server (NTRS)

    Gorjala, B.; Sayood, Khalid; Meempat, G.

    1992-01-01

    A low complexity technique for compression of images for transmission over local area networks is presented. The technique uses the synchronous traffic as a side channel for improving the performance of an adaptive differential pulse code modulation (ADPCM) based coder.

  18. Application of digital image processing techniques to astronomical imagery 1977

    NASA Technical Reports Server (NTRS)

    Lorre, J. J.; Lynn, D. J.

    1978-01-01

    Nine specific techniques of combination of techniques developed for applying digital image processing technology to existing astronomical imagery are described. Photoproducts are included to illustrate the results of each of these investigations.

  19. A content-based image retrieval method for optical colonoscopy images based on image recognition techniques

    NASA Astrophysics Data System (ADS)

    Nosato, Hirokazu; Sakanashi, Hidenori; Takahashi, Eiichi; Murakawa, Masahiro

    2015-03-01

    This paper proposes a content-based image retrieval method for optical colonoscopy images that can find images similar to ones being diagnosed. Optical colonoscopy is a method of direct observation for colons and rectums to diagnose bowel diseases. It is the most common procedure for screening, surveillance and treatment. However, diagnostic accuracy for intractable inflammatory bowel diseases, such as ulcerative colitis (UC), is highly dependent on the experience and knowledge of the medical doctor, because there is considerable variety in the appearances of colonic mucosa within inflammations with UC. In order to solve this issue, this paper proposes a content-based image retrieval method based on image recognition techniques. The proposed retrieval method can find similar images from a database of images diagnosed as UC, and can potentially furnish the medical records associated with the retrieved images to assist the UC diagnosis. Within the proposed method, color histogram features and higher order local auto-correlation (HLAC) features are adopted to represent the color information and geometrical information of optical colonoscopy images, respectively. Moreover, considering various characteristics of UC colonoscopy images, such as vascular patterns and the roughness of the colonic mucosa, we also propose an image enhancement method to highlight the appearances of colonic mucosa in UC. In an experiment using 161 UC images from 32 patients, we demonstrate that our method improves the accuracy of retrieving similar UC images.

  20. Selective document image data compression technique

    DOEpatents

    Fu, C.Y.; Petrich, L.I.

    1998-05-19

    A method of storing information from filled-in form-documents comprises extracting the unique user information in the foreground from the document form information in the background. The contrast of the pixels is enhanced by a gamma correction on an image array, and then the color value of each of pixel is enhanced. The color pixels lying on edges of an image are converted to black and an adjacent pixel is converted to white. The distance between black pixels and other pixels in the array is determined, and a filled-edge array of pixels is created. User information is then converted to a two-color format by creating a first two-color image of the scanned image by converting all pixels darker than a threshold color value to black. All the pixels that are lighter than the threshold color value to white. Then a second two-color image of the filled-edge file is generated by converting all pixels darker than a second threshold value to black and all pixels lighter than the second threshold color value to white. The first two-color image and the second two-color image are then combined and filtered to smooth the edges of the image. The image may be compressed with a unique Huffman coding table for that image. The image file is also decimated to create a decimated-image file which can later be interpolated back to produce a reconstructed image file using a bilinear interpolation kernel. 10 figs.

  1. Selective document image data compression technique

    DOEpatents

    Fu, Chi-Yung; Petrich, Loren I.

    1998-01-01

    A method of storing information from filled-in form-documents comprises extracting the unique user information in the foreground from the document form information in the background. The contrast of the pixels is enhanced by a gamma correction on an image array, and then the color value of each of pixel is enhanced. The color pixels lying on edges of an image are converted to black and an adjacent pixel is converted to white. The distance between black pixels and other pixels in the array is determined, and a filled-edge array of pixels is created. User information is then converted to a two-color format by creating a first two-color image of the scanned image by converting all pixels darker than a threshold color value to black. All the pixels that are lighter than the threshold color value to white. Then a second two-color image of the filled-edge file is generated by converting all pixels darker than a second threshold value to black and all pixels lighter than the second threshold color value to white. The first two-color image and the second two-color image are then combined and filtered to smooth the edges of the image. The image may be compressed with a unique Huffman coding table for that image. The image file is also decimated to create a decimated-image file which can later be interpolated back to produce a reconstructed image file using a bilinear interpolation kernel.--(235 words)

  2. Bayesian technique for image classifying registration.

    PubMed

    Hachama, Mohamed; Desolneux, Agnès; Richard, Frédéric J P

    2012-09-01

    In this paper, we address a complex image registration issue arising while the dependencies between intensities of images to be registered are not spatially homogeneous. Such a situation is frequently encountered in medical imaging when a pathology present in one of the images modifies locally intensity dependencies observed on normal tissues. Usual image registration models, which are based on a single global intensity similarity criterion, fail to register such images, as they are blind to local deviations of intensity dependencies. Such a limitation is also encountered in contrast-enhanced images where there exist multiple pixel classes having different properties of contrast agent absorption. In this paper, we propose a new model in which the similarity criterion is adapted locally to images by classification of image intensity dependencies. Defined in a Bayesian framework, the similarity criterion is a mixture of probability distributions describing dependencies on two classes. The model also includes a class map which locates pixels of the two classes and weighs the two mixture components. The registration problem is formulated both as an energy minimization problem and as a maximum a posteriori estimation problem. It is solved using a gradient descent algorithm. In the problem formulation and resolution, the image deformation and the class map are estimated simultaneously, leading to an original combination of registration and classification that we call image classifying registration. Whenever sufficient information about class location is available in applications, the registration can also be performed on its own by fixing a given class map. Finally, we illustrate the interest of our model on two real applications from medical imaging: template-based segmentation of contrast-enhanced images and lesion detection in mammograms. We also conduct an evaluation of our model on simulated medical data and show its ability to take into account spatial variations

  3. Overview of image security techniques with applications in multimedia systems

    NASA Astrophysics Data System (ADS)

    Wolfgang, Raymond B.; Delp, Edward J., III

    1998-02-01

    The growth of networked multimedia system has created a need for the copyright protection of digital images and video. Copyright protection involves the authentication of image content and/or ownership. This can be used to identify illegal copies of an image. One approach is to mark an image by adding an invisible structure known as a digital watermark to the image. Techniques of incorporating such a watermark into digital images include spatial-domain techniques, transform-domain algorithms and sub-band filtering approaches.

  4. Various diffusion magnetic resonance imaging techniques for pancreatic cancer

    PubMed Central

    Tang, Meng-Yue; Zhang, Xiao-Ming; Chen, Tian-Wu; Huang, Xiao-Hua

    2015-01-01

    Pancreatic cancer is one of the most common malignant tumors and remains a treatment-refractory cancer with a poor prognosis. Currently, the diagnosis of pancreatic neoplasm depends mainly on imaging and which methods are conducive to detecting small lesions. Compared to the other techniques, magnetic resonance imaging (MRI) has irreplaceable advantages and can provide valuable information unattainable with other noninvasive or minimally invasive imaging techniques. Advances in MR hardware and pulse sequence design have particularly improved the quality and robustness of MRI of the pancreas. Diffusion MR imaging serves as one of the common functional MRI techniques and is the only technique that can be used to reflect the diffusion movement of water molecules in vivo. It is generally known that diffusion properties depend on the characterization of intrinsic features of tissue microdynamics and microstructure. With the improvement of the diffusion models, diffusion MR imaging techniques are increasingly varied, from the simplest and most commonly used technique to the more complex. In this review, the various diffusion MRI techniques for pancreatic cancer are discussed, including conventional diffusion weighted imaging (DWI), multi-b DWI based on intra-voxel incoherent motion theory, diffusion tensor imaging and diffusion kurtosis imaging. The principles, main parameters, advantages and limitations of these techniques, as well as future directions for pancreatic diffusion imaging are also discussed. PMID:26753059

  5. Forensic Techniques for Image Source Classification: A Comparative Study

    NASA Astrophysics Data System (ADS)

    Delp, Edward J.

    Digital images can be captured or generated by a variety of sources including digital cameras, scanners and computer graphics softwares. In many cases it is important to be able to determine the source of a digital image such as for criminal and forensic investigation. Based on their originating mechanism digital images can be classified into three classes: digital camera images, scanner generated images and computer-graphics generated images. Image source classification is helpful as a first step for identifying the unique device or system which produced the image. This paper presents a survey of different methods for solving image source classification problem, some improvements over them and compares their performance in a common framework. As expected with the advances in computer graphics techniques, artificial images are becoming closer and closer to the natural ones and harder to distinguish by human visual system. Hence, the methods based on characteristics of image generating process are more successful than those based on image content.

  6. Lower radiation burden in state of the art fluoroscopic cystography compared to direct isotope cystography in children.

    PubMed

    Haid, Bernhard; Becker, Tanja; Koen, Mark; Berger, Christoph; Langsteger, Werner; Gruy, Bernhard; Putz, Ernst; Haid, Stephanie; Oswald, Josef

    2015-02-01

    filling until calculated bladder capacity, mean radiation burden accounted to .07 mSv (median 0.07 mSv) and the values were less scattered. As it had to be expected from literature, radiation dose from fVCUG, if modern image acquisition techniques are used, is even less than from DIC. In our protocol, according to nuclear medicine standards, bladders were filled until calculated capacity. This resulted in a longer examination time for the patients with a higher functional capacity, resulting in relatively higher radiation burden. However, also if the protocol is changed or only the patients with relatively fast bladder emptying are considered, radiation burden conferred by DIC is higher (at least × 2.9, comparing the "worst" case for fVCUG with the "best" case for DIC). Absolute radiation burden conferred by either exam is extremely low compared to other medical radiation exposures as well as to environmental radiation. Consequently it is most probably not relevant for the individual childs future risk for cancer or other radiation damage. However, because of repeated investigations with correspondingly higher radiation burden in this patient group the ALARA (as low as reasonably achievable) principle should lead to a optimized use of fVCUG rather than an uncritical use of DIC, given that modern acquisition standards are available and radiation measurement is performed. Also, fVCUG provides more information concerning anatomical details compared to DIC. Contrary to common beliefs, effective radiation dose conferred during fluoroscopic voiding cystourethrography is significantly lower than during direct isotope cystography. The prerequisite for our findings, however, is the use of modern image acquisition tools and an optimized protocol. Both exams confer low radiation doses probably only relevant to children undergoing repeated radiation exposure. Nevertheless, this findings should be considered in indication for either exam in order to reduce the radiation burden to a

  7. Organ and effective doses in infants undergoing upper gastrointestinal (UGI) fluoroscopic examination

    SciTech Connect

    Staton, Robert J.; Williams, Jonathon L.; Arreola, Manuel M.; Hintenlang, David E.; Bolch, Wesley E.

    2007-02-15

    To provide more detailed data on organ and effective doses in digital upper gastrointestinal (UGI) fluoroscopy studies of newborns and infants, the present study was conducted employing the time-sequence videotape-analysis technique used in a companion study of newborn and infant voiding cystourethrograms (VCUG). This technique was originally pioneered [O. H. Suleiman, J. Anderson, B. Jones, G. U. Rao, and M. Rosenstein, Radiology 178, 653-658 (1991)] for adult UGI examinations. Individual video frames were analyzed to include combinations of field size, field center, x-ray projection, image intensifier, and magnification mode. Additionally, the peak tube potential and the mA or mAs values for each segment/subsegment or digital photospot were recorded for both the fluoroscopic and radiographic modes of operation. The data from videotape analysis were then used in conjunction with a patient-scalable newborn tomographic computational phantom to report both organ and effective dose values via Monte Carlo radiation transport. The study includes dose estimates for five simulated UGI examinations representative of patients ranging from three to six months of age. Effective dose values for UGI examinations ranged from 1.17 to 6.47 mSv, with a mean of 3.14 mSv and a large standard deviation of 2.15 mSv. The colon, lungs, stomach, liver, and esophagus absorbed doses in sum were found to constitute between 63 and 75% of the effective dose in these UGI studies. Representing 23-30% of the effective dose, the lungs were found to be the most significant organ in the effective dose calculation. Approximately 80-95% of the effective dose is contributed by the dynamic fluoroscopy segments with larger percentages found in longer studies. The mean effective dose for newborn UGI examinations was not found to be statistically different from that seen in newborn VCUG examinations.

  8. Unconventional techniques of fundus imaging: A review.

    PubMed

    Shanmugam, Mahesh P; Mishra, Divyansh Kailash Chandra; Rajesh, R; Madhukumar, R

    2015-07-01

    The methods of fundus examination include direct and indirect ophthalmoscopy and imaging with a fundus camera are an essential part of ophthalmic practice. The usage of unconventional equipment such as a hand-held video camera, smartphone, and a nasal endoscope allows one to image the fundus with advantages and some disadvantages. The advantages of these instruments are the cost-effectiveness, ultra portability and ability to obtain images in a remote setting and share the same electronically. These instruments, however, are unlikely to replace the fundus camera but then would always be an additional arsenal in an ophthalmologist's armamentarium.

  9. Fluoroscopically-guided micropuncture femoral artery access for large-caliber sheath insertion.

    PubMed

    Cilingiroglu, Mehmet; Feldman, Ted; Salinger, Michael H; Levisay, Justin; Turi, Zoltan G

    2011-04-01

    Over the last decade, significant developments have been made in the treatment of structural heart disease. Some of these techniques require placement of large arterial sheaths for device delivery. Optimal vascular access is essential for successful large-vessel sheath insertion as well as to avoid vascular complications. The critical step for ideal percutaneous vessel entry is single anterior wall-only puncture of the common femoral artery in a location above the femoral bifurcation and below the inguinal ligament. We describe a fluoroscopically-guided micropuncture technique for accurate placement of large-caliber arterial sheaths.

  10. Holographic Radar Imaging Privacy Techniques Utilizing Dual-Frequency Implementation

    SciTech Connect

    McMakin, Douglas L.; Hall, Thomas E.; Sheen, David M.

    2008-04-18

    Over the last 15 years, the Pacific Northwest National Laboratory has performed significant research and development activities to enhance the state of the art of holographic radar imaging systems to be used at security checkpoints for screening people for concealed threats hidden under their garments. These enhancement activities included improvements to privacy techniques to remove human features and providing automatic detection of body-worn concealed threats. The enhanced privacy and detection methods used both physical and software imaging techniques. The physical imaging techniques included polarization-diversity illumination and reception, dual-frequency implementation, and high-frequency imaging at 60 GHz. Software imaging techniques to enhance the privacy of the person under surveillance included extracting concealed threat artifacts from the imagery to automatically detect the threat. This paper will focus on physical privacy techniques using dual-frequency implementation.

  11. Combined neutron imaging techniques for cultural heritage purpose

    SciTech Connect

    Materna, T.

    2009-01-28

    This article presents the different new neutron techniques developed by the Ancient Charm collaboration to image objects of cultural heritage importance: Prompt-gamma-ray activation imaging (PGAI) coupled to cold/thermal neutron transmission tomography, Neutron Resonance Capture Imaging (NRCI) and Neutron Resonance Tomography.

  12. Laser image denoising technique based on multi-fractal theory

    NASA Astrophysics Data System (ADS)

    Du, Lin; Sun, Huayan; Tian, Weiqing; Wang, Shuai

    2014-02-01

    The noise of laser images is complex, which includes additive noise and multiplicative noise. Considering the features of laser images, the basic processing capacity and defects of the common algorithm, this paper introduces the fractal theory into the research of laser image denoising. The research of laser image denoising is implemented mainly through the analysis of the singularity exponent of each pixel in fractal space and the feature of multi-fractal spectrum. According to the quantitative and qualitative evaluation of the processed image, the laser image processing technique based on fractal theory not only effectively removes the complicated noise of the laser images obtained by range-gated laser active imaging system, but can also maintains the detail information when implementing the image denoising processing. For different laser images, multi-fractal denoising technique can increase SNR of the laser image at least 1~2dB compared with other denoising techniques, which basically meet the needs of the laser image denoising technique.

  13. Investigation of Antiangiogenic Mechanisms Using Novel Imaging Techniques

    DTIC Science & Technology

    2010-02-01

    Biomed. Opt. 95, 982–994 2004. 6. M. Khurana, E. H. Moriyama, A. Mariampillai, and B. C. Wilson, “ Intravital high-resolution optical imaging of...Mechanisms Using Novel Imaging Techniques PRINCIPAL INVESTIGATOR: Andrew Fontanella CONTRACTING ORGANIZATION: Duke University Durham...Using Novel Imaging Techniques 5b. GRANT NUMBER W81XWH-09-1-0113 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Andrew Fontanella

  14. Technique for identifying, tracing, or tracking objects in image data

    DOEpatents

    Anderson, Robert J [Albuquerque, NM; Rothganger, Fredrick [Albuquerque, NM

    2012-08-28

    A technique for computer vision uses a polygon contour to trace an object. The technique includes rendering a polygon contour superimposed over a first frame of image data. The polygon contour is iteratively refined to more accurately trace the object within the first frame after each iteration. The refinement includes computing image energies along lengths of contour lines of the polygon contour and adjusting positions of the contour lines based at least in part on the image energies.

  15. Phase Diversity and Polarization Augmented Techniques for Active Imaging

    DTIC Science & Technology

    2007-03-01

    Phase Diversity and Polarization Augmented Techniques for Active Imaging DISSERTATION Peter M. Johnson, Captain, USAF AFIT/DS/ENG/07-05 DEPARTMENT OF...Force, Department of Defense, or the United States Government. AFIT/DS/ENG/07-05 Phase Diversity and Polarization Augmented Techniques for Active Imaging...must be used. To facilitate this, a multi-frame active phase diversity imaging (APDI) algorithm is derived and demonstrated for the statistics of

  16. Real-time optical image processing techniques

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang

    1988-01-01

    Nonlinear real-time optical processing on spatial pulse frequency modulation has been pursued through the analysis, design, and fabrication of pulse frequency modulated halftone screens and the modification of micro-channel spatial light modulators (MSLMs). Micro-channel spatial light modulators are modified via the Fabry-Perot method to achieve the high gamma operation required for non-linear operation. Real-time nonlinear processing was performed using the halftone screen and MSLM. The experiments showed the effectiveness of the thresholding and also showed the needs of higher SBP for image processing. The Hughes LCLV has been characterized and found to yield high gamma (about 1.7) when operated in low frequency and low bias mode. Cascading of two LCLVs should also provide enough gamma for nonlinear processing. In this case, the SBP of the LCLV is sufficient but the uniformity of the LCLV needs improvement. These include image correlation, computer generation of holograms, pseudo-color image encoding for image enhancement, and associative-retrieval in neural processing. The discovery of the only known optical method for dynamic range compression of an input image in real-time by using GaAs photorefractive crystals is reported. Finally, a new architecture for non-linear multiple sensory, neural processing has been suggested.

  17. Real-time optical image processing techniques

    NASA Astrophysics Data System (ADS)

    Liu, Hua-Kuang

    1988-10-01

    Nonlinear real-time optical processing on spatial pulse frequency modulation has been pursued through the analysis, design, and fabrication of pulse frequency modulated halftone screens and the modification of micro-channel spatial light modulators (MSLMs). Micro-channel spatial light modulators are modified via the Fabry-Perot method to achieve the high gamma operation required for non-linear operation. Real-time nonlinear processing was performed using the halftone screen and MSLM. The experiments showed the effectiveness of the thresholding and also showed the needs of higher SBP for image processing. The Hughes LCLV has been characterized and found to yield high gamma (about 1.7) when operated in low frequency and low bias mode. Cascading of two LCLVs should also provide enough gamma for nonlinear processing. In this case, the SBP of the LCLV is sufficient but the uniformity of the LCLV needs improvement. These include image correlation, computer generation of holograms, pseudo-color image encoding for image enhancement, and associative-retrieval in neural processing. The discovery of the only known optical method for dynamic range compression of an input image in real-time by using GaAs photorefractive crystals is reported. Finally, a new architecture for non-linear multiple sensory, neural processing has been suggested.

  18. Comparison and improvement of color-based image retrieval techniques

    NASA Astrophysics Data System (ADS)

    Zhang, Yujin; Liu, Zhong W.; He, Yun

    1997-12-01

    With the increasing popularity of image manipulation with contents, many color-based image retrieval techniques have been proposed in the literature. A systematic and comparative study of 8 representative techniques is first presented in this paper, which uses a database of 200 images of flags and trademarks. These techniques are determined to cover the variations of the color models used, of the characteristic color features employed and of the distance measures calculated for judging the similarity of color images. The results of this comparative study are presented both by the list of retrieved images for subjective visual inspection and by the retrieving ratios computed for objective judgement. All of them show that the cumulative histogram based techniques using Euclidean distance measures in two perception related color spaces give best results among the 8 techniques under consideration. Started from the best performed techniques, works toward further improving their retrieving capability are then carried on and this has resulted 2 new techniques which use local cumulative histograms. The new techniques have been tested by using a database of 400 images of real flowers which are quite complicated in color contents. Some satisfactory results, compared to that obtained by using existing cumulative histogram based techniques are obtained and presented.

  19. Steganalysis Techniques for Documents and Images

    DTIC Science & Technology

    2007-11-02

    generalized our previous steganalysis technique of sample pair analysis to a theoretical framework for the detection of the LSB steganography . The new...steganalysis technique of sample pair analysis to a theoretical framework for the detection of the LSB steganography . The new framework exploits high-order... steganography as an additive noise process and measuring the mean and variance of the stego-signal. We derived a formula that governs all additive

  20. Externally triggered imaging technique for microbolometer-type terahertz imager

    NASA Astrophysics Data System (ADS)

    Oda, Naoki; Sudou, Takayuki; Ishi, Tsutomu; Okubo, Syuichi; Isoyama, Goro; Irizawa, Akinori; Kawase, Keigo; Kato, Ryukou

    2016-04-01

    The authors developed terahertz (THz) imager which incorporates 320x240 focal plane array (FPA) with enhanced sensitivity in sub-THz region (ca. 0.5 THz). The imager includes functions such as external-trigger imaging, lock-in imaging, beam profiling and so on. The function of the external-trigger imaging is mainly described in this paper, which was verified in combination of the THz imager with the pulsed THz free electron laser (THz-FEL) developed by Osaka University. The THz-FEL emits THz radiation in a wavelength range of 25 - 150 μm at repetition rates of 2.5, 3.3, 5.0 and 10 pulses per second. The external trigger pulse for the THz imager was generated with a pulse generator, using brightening pulse for THz-FEL. A series of pulses emitted by the THz-FEL at 86 μm were introduced to the THz imager and Joule meter via beam splitter, so that the output signal of THz imager was normalized with the output of the Joule meter and the stability of the THz radiation from FEL was also monitored. The normalized output signals of THz imager (digits/μJ) obtained at the repetition rates mentioned above were found consistent with one another. The timing-relation of the external trigger pulse to the brightening pulse was varied and the influence of the timing-relation on beam pattern is presented. These experimental results verify that the external trigger imaging function operates correctly.

  1. Infrared Imaging Data Reduction Software and Techniques

    NASA Astrophysics Data System (ADS)

    Sabbey, C. N.; McMahon, R. G.; Lewis, J. R.; Irwin, M. J.

    Developed to satisfy certain design requirements not met in existing packages (e.g., full weight map handling) and to optimize the software for large data sets (non-interactive tasks that are CPU and disk efficient), the InfraRed Data Reduction software package is a small ANSI C library of fast image processing routines for automated pipeline reduction of infrared (dithered) observations. The software includes stand-alone C programs for tasks such as running sky frame subtraction with object masking, image registration and co-addition with weight maps, dither offset measurement using cross-correlation, and object mask dilation. Although currently used for near-IR mosaic images, the modular software is concise and readily adaptable for reuse in other work. IRDR, available via anonymous ftp at ftp.ast.cam.ac.uk in pub/sabbey

  2. Cartilage imaging in children: current indications, magnetic resonance imaging techniques, and imaging findings.

    PubMed

    Ho-Fung, Victor M; Jaramillo, Diego

    2013-07-01

    Evaluation of hyaline cartilage in pediatric patients requires in-depth understanding of normal physiologic changes in the developing skeleton. Magnetic resonance (MR) imaging is a powerful tool for morphologic and functional imaging of the cartilage. In this review article, current imaging indications for cartilage evaluation pertinent to the pediatric population are described. In particular, novel surgical techniques for cartilage repair and MR classification of cartilage injuries are summarized. The authors also provide a review of the normal anatomy and a concise description of the advances in quantitative cartilage imaging (ie, T2 mapping, delayed gadolinium-enhanced MR imaging of cartilage, and T1rho). Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Development of neutron tomography and phase contrast imaging technique

    SciTech Connect

    Kashyap, Y. S.; Agrawal, Ashish; Sarkar, P. S.; Shukla, Mayank; Sinha, Amar

    2013-02-05

    This paper presents design and development of a state of art neutron imaging technique at CIRUS reactor with special reference for techniques adopted for tomography and phase contrast imaging applications. Different components of the beamline such as collimator, shielding, sample manipulator, digital imaging system were designed keeping in mind the requirements of data acquisition time and resolution. The collimator was designed in such a way that conventional and phase contrast imaging can be done using same collimator housing. We have done characterization of fuel pins, study of hydride blisters in pressure tubes hydrogen based cells, two phase flow visualization, and online study of locomotive parts etc. using neutron tomography and radiography technique. We have also done some studies using neutron phase contrast imaging technique on this beamline.

  4. Development of neutron tomography and phase contrast imaging technique

    NASA Astrophysics Data System (ADS)

    Kashyap, Y. S.; Agrawal, Ashish; Sarkar, P. S.; Shukla, Mayank; Sinha, Amar

    2013-02-01

    This paper presents design and development of a state of art neutron imaging technique at CIRUS reactor with special reference for techniques adopted for tomography and phase contrast imaging applications. Different components of the beamline such as collimator, shielding, sample manipulator, digital imaging system were designed keeping in mind the requirements of data acquisition time and resolution. The collimator was designed in such a way that conventional and phase contrast imaging can be done using same collimator housing. We have done characterization of fuel pins, study of hydride blisters in pressure tubes hydrogen based cells, two phase flow visualization, and online study of locomotive parts etc. using neutron tomography and radiography technique. We have also done some studies using neutron phase contrast imaging technique on this beamline.

  5. Neurovascular coupling: in vivo optical techniques for functional brain imaging.

    PubMed

    Liao, Lun-De; Tsytsarev, Vassiliy; Delgado-Martínez, Ignacio; Li, Meng-Lin; Erzurumlu, Reha; Vipin, Ashwati; Orellana, Josue; Lin, Yan-Ren; Lai, Hsin-Yi; Chen, You-Yin; Thakor, Nitish V

    2013-04-30

    Optical imaging techniques reflect different biochemical processes in the brain, which is closely related with neural activity. Scientists and clinicians employ a variety of optical imaging technologies to visualize and study the relationship between neurons, glial cells and blood vessels. In this paper, we present an overview of the current optical approaches used for the in vivo imaging of neurovascular coupling events in small animal models. These techniques include 2-photon microscopy, laser speckle contrast imaging (LSCI), voltage-sensitive dye imaging (VSDi), functional photoacoustic microscopy (fPAM), functional near-infrared spectroscopy imaging (fNIRS) and multimodal imaging techniques. The basic principles of each technique are described in detail, followed by examples of current applications from cutting-edge studies of cerebral neurovascular coupling functions and metabolic. Moreover, we provide a glimpse of the possible ways in which these techniques might be translated to human studies for clinical investigations of pathophysiology and disease. In vivo optical imaging techniques continue to expand and evolve, allowing us to discover fundamental basis of neurovascular coupling roles in cerebral physiology and pathophysiology.

  6. Neurovascular coupling: in vivo optical techniques for functional brain imaging

    PubMed Central

    2013-01-01

    Optical imaging techniques reflect different biochemical processes in the brain, which is closely related with neural activity. Scientists and clinicians employ a variety of optical imaging technologies to visualize and study the relationship between neurons, glial cells and blood vessels. In this paper, we present an overview of the current optical approaches used for the in vivo imaging of neurovascular coupling events in small animal models. These techniques include 2-photon microscopy, laser speckle contrast imaging (LSCI), voltage-sensitive dye imaging (VSDi), functional photoacoustic microscopy (fPAM), functional near-infrared spectroscopy imaging (fNIRS) and multimodal imaging techniques. The basic principles of each technique are described in detail, followed by examples of current applications from cutting-edge studies of cerebral neurovascular coupling functions and metabolic. Moreover, we provide a glimpse of the possible ways in which these techniques might be translated to human studies for clinical investigations of pathophysiology and disease. In vivo optical imaging techniques continue to expand and evolve, allowing us to discover fundamental basis of neurovascular coupling roles in cerebral physiology and pathophysiology. PMID:23631798

  7. Compression technique for plume hyperspectral images

    NASA Astrophysics Data System (ADS)

    Feather, B. K.; Fulkerson, S. A.; Jones, J. H.; Reed, R. A.; Simmons, M. A.; Swann, D. G.; Taylor, W. E.; Bernstein, L. S.

    2005-06-01

    The authors recently developed a hyperspectral image output option for a standardized government code designed to predict missile exhaust plume infrared signatures. Typical predictions cover the 2- to 5-m wavelength range (2000 to 5000 cm-1) at 5 cm-1 spectral resolution, and as a result the hyperspectral images have several hundred frequency channels. Several hundred hyperspectral plume images are needed to span the full operational envelope of missile altitude, Mach number, and aspect angle. Since the net disk storage space can be as large as 100 GB, a Principal Components Analysis is used to compress the spectral dimension, reducing the volume of data to just a few gigabytes. The principal challenge was to specify a robust default setting for the data compression routine suitable for general users, who are not necessarily specialists in data compression. Specifically, the objective was to provide reasonable data compression efficiency of the hyperspectral imagery while at the same time retaining sufficient accuracy for infrared scene generation and hardware-in-the-loop test applications over a range of sensor bandpasses and scenarios. In addition, although the end users of the code do not usually access the detailed spectral information contained in these hyperspectral images, this information must nevertheless be of sufficient fidelity so that atmospheric transmission losses between the missile plume and the sensor could be reliably computed as a function of range. Several metrics were used to determine how far the plume signature hyperspectral data could be safely compressed while still meeting these end-user requirements.

  8. Diffusion weighted imaging: Technique and applications

    PubMed Central

    Baliyan, Vinit; Das, Chandan J; Sharma, Raju; Gupta, Arun Kumar

    2016-01-01

    Diffusion weighted imaging (DWI) is a method of signal contrast generation based on the differences in Brownian motion. DWI is a method to evaluate the molecular function and micro-architecture of the human body. DWI signal contrast can be quantified by apparent diffusion coefficient maps and it acts as a tool for treatment response evaluation and assessment of disease progression. Ability to detect and quantify the anisotropy of diffusion leads to a new paradigm called diffusion tensor imaging (DTI). DTI is a tool for assessment of the organs with highly organised fibre structure. DWI forms an integral part of modern state-of-art magnetic resonance imaging and is indispensable in neuroimaging and oncology. DWI is a field that has been undergoing rapid technical evolution and its applications are increasing every day. This review article provides insights in to the evolution of DWI as a new imaging paradigm and provides a summary of current role of DWI in various disease processes. PMID:27721941

  9. Recovering depth from focus using iterative image estimation techniques

    SciTech Connect

    Vitria, J.; Llacer, J.

    1993-09-01

    In this report we examine the possibility of using linear and nonlinear image estimation techniques to build a depth map of a three dimensional scene from a sequence of partially focused images. In particular, the techniques proposed to solve the problem of construction of a depth map are: (1) linear methods based on regularization procedures and (2) nonlinear methods based on statistical modeling. In the first case, we have implemented a matrix-oriented method to recover the point spread function (PSF) of a sequence of partially defocused images. In the second case, the chosen method has been a procedure based on image estimation by means of the EM algorithm, a well known technique in image reconstruction in medical applications. This method has been generalized to deal with optically defocused image sequences.

  10. Towards Automatic Image Segmentation Using Optimised Region Growing Technique

    NASA Astrophysics Data System (ADS)

    Alazab, Mamoun; Islam, Mofakharul; Venkatraman, Sitalakshmi

    Image analysis is being adopted extensively in many applications such as digital forensics, medical treatment, industrial inspection, etc. primarily for diagnostic purposes. Hence, there is a growing interest among researches in developing new segmentation techniques to aid the diagnosis process. Manual segmentation of images is labour intensive, extremely time consuming and prone to human errors and hence an automated real-time technique is warranted in such applications. There is no universally applicable automated segmentation technique that will work for all images as the image segmentation is quite complex and unique depending upon the domain application. Hence, to fill the gap, this paper presents an efficient segmentation algorithm that can segment a digital image of interest into a more meaningful arrangement of regions and objects. Our algorithm combines region growing approach with optimised elimination of false boundaries to arrive at more meaningful segments automatically. We demonstrate this using X-ray teeth images that were taken for real-life dental diagnosis.

  11. Verification of Ultrasonic Image Fusion Technique for Laparoscopic Surgery

    NASA Astrophysics Data System (ADS)

    Zenbutsu, Satoki; Igarashi, Tatsuo; Mamou, Jonathan; Yamaguchi, Tadashi

    2012-07-01

    Laparoscopic surgery is one of the most challenging surgical operations, because inside information about the target organ cannot be fully understood from the laparoscopic image. Therefore, a fusion technique of laparoscopic and ultrasonic images is proposed for guidance during laparoscopic surgery. The proposed technique can display the internal organ structure by overlaying a three-dimensional (3D) ultrasonic image over a 3D laparoscopic image, which is acquired using a stereo laparoscope. The registration of the 3D images is performed by registering the surface of the target organ, which is found in the two 3D images without requiring the use of an external position detecting device. The proposed technique was evaluated experimentally using a tissue-mimicking phantom. Results obtained led to registration accuracy better than 2 cm. The total computation time was 3.1 min on a personal computer (Xeon processor, 3 GHz CPU). The structural information permits the visualization of target organs during laparoscopic surgery.

  12. The use of dual C-arms during fixation of calcaneal fractures: a technique tip.

    PubMed

    Abousayed, Mostafa M; Toussaint, Rull James; Kwon, John Y

    2014-06-01

    We describe a simple technique using dual C-arms (large and mini C-arm together) for open reduction internal fixation of calcaneal fractures in the lateral decubitus position that (1) decreases the difficulty of obtaining proper intraoperative imaging; (2) limits C-arm movement, which decreases risk of contamination and operative time; and (3) minimizes the drawbacks of each imaging fluoroscopic modality. Level V, Technical tip, Expert opinion.

  13. Color-gamut mapping techniques for color hardcopy images

    NASA Astrophysics Data System (ADS)

    Hoshino, Toru; Berns, Roy S.

    1993-08-01

    Color gamut mapping is required whenever two imaging devices do not have coincident color gamuts or viewing conditions. Two major gamut mapping techniques include lightness and chroma manipulations. Lightness mapping accounts for differences in white level, black level, and viewing conditions while chroma mapping accounts for differences in gamut volume. As a three dimensional space in which color gamut mapping is implemented, the 1991 Hunt model of color appearance was used utilizing dimensions of lightness, chroma, and hue. This model accounts for viewing conditions in addition to the usual device independent specification. The mapping techniques were applied to back-lit photographic transparencies in order to reproduce images using a dye diffusion thermal transfer printer. As the first experiment, a lightness mapping experiment was performed. Three different lightness mapping techniques, a linear technique and two non-linear techniques, were tested for four images. The psychophysical method of paired comparison was used to generate interval scales of preferred color reproduction. In general, the preferred technique depended on the amount of lightness mapping required and on the original image's lightness histograms. For small amounts of compression, the preferred technique was a clipping type. For large amounts of compression, the preferred technique was image dependent; low preference was caused by loss of detail or apparent fluorescence of high chroma image areas.

  14. Cylindrical millimeter-wave imaging technique and applications

    NASA Astrophysics Data System (ADS)

    Sheen, David M.; McMakin, Douglas L.; Hall, Thomas E.

    2006-05-01

    The wideband microwave or millimeter-wave cylindrical imaging technique has been developed at Pacific Northwest National Laboratory (PNNL) for several applications including concealed weapon detection and automated body measurement for apparel fitting. This technique forms a fully-focused, diffraction-limited, three-dimensional image of the person or imaging target by scanning an inward-directed vertical array around the person or imaging target. The array is switched electronically to sequence across the array at high-speed, so that a full 360 degree mechanical scan over the cylindrical aperture can occur in 2-10 seconds. Wideband, coherent reflection data from each antenna position are recorded in a computer and subsequently reconstructed using an FFT-based image reconstruction algorithm developed at PNNL. The cylindrical scanning configuration is designed to optimize the illumination of the target and minimize non-returns due to specular reflection of the illumination away from the array. In this paper, simulated modeling data are used to explore imaging issues that affect the cylindrical imaging technique. Physical optics scattering simulations are used to model realistic returns from curved surfaces to determine the extent to which specular reflection affects the signal return and subsequent image reconstruction from these surfaces. This is a particularly important issue for the body measurement application. Also, an artifact in the imaging technique, referred to as "circular convolution aliasing" is discussed including methods to reduce or eliminate it. Numerous simulated and laboratory measured imaging results are presented.

  15. Cylindrical Millemeter-Wave Imaging Technique and Applications

    SciTech Connect

    Sheen, David M.; McMakin, Douglas L.; Hall, Thomas E.

    2006-08-01

    The wideband microwave or millimeter-wave cylindrical imaging technique has been developed at Pacific Northwest National Laboratory (PNNL) for several applications including concealed weapon detection and automated body measurements for apparel fitting. This technique forms a fully-focused, diffraction-limited, three-dimensional image of the person or imaging target by scanning an inward-directed vertical array around the person or imaging target. The array is switched electronically to sequence across the array at high-speed, so that a full 360 degree mechanical scan over the cylindrical aperture can occur in 2-10 seconds. Wideband, coherent reflection data from each antenna position are recorded in a computer and subsequently reconstructed using an FFT-based image reconstruction algorithm developed at PNNL. The cylindrical scanning configuration is designed to optimize the illumination of the target and minimize non-returns due to specular reflection of the illumination away from the array. In this paper, simulated modeling data is used to explore imaging issues that affect the cylindrical imaging technique. Physical optics scattering simulations are used to model realistic returns from curved surfaces to determine the extent to which specular reflection affects the signal return and subsequent image reconstruction from these surfaces. This is a particularly important issue for the body measurement application. Also, an artifact in the imaging technique, referred to as "circular convolution aliasing" is discussed including methods to reduce or eliminate it. Numerous simulated and laboratory measured imaging results are presented.

  16. Hierarchical clustering techniques for image database organization and summarization

    NASA Astrophysics Data System (ADS)

    Vellaikal, Asha; Kuo, C.-C. Jay

    1998-10-01

    This paper investigates clustering techniques as a method of organizing image databases to support popular visual management functions such as searching, browsing and navigation. Different types of hierarchical agglomerative clustering techniques are studied as a method of organizing features space as well as summarizing image groups by the selection of a few appropriate representatives. Retrieval performance using both single and multiple level hierarchies are experimented with and the algorithms show an interesting relationship between the top k correct retrievals and the number of comparisons required. Some arguments are given to support the use of such cluster-based techniques for managing distributed image databases.

  17. Combined MRI and Fluoroscopic Guided Radiofrequency Ablation of a Renal Tumor

    SciTech Connect

    Fotiadis, Nikolas I.; Sabharwal, Tarun; Gangi, Afshin; Adam, Andreas

    2009-01-15

    Percutaneous CT- and ultrasound-guided radiofrequency ablation of renal cell carcinoma (RCC) has been shown to have very promising medium-term results. We present a unique case of recurrent RCC after partial nephrectomy in a patient with a single kidney and impaired renal function. This tumor could not be visualized either with CT or with ultrasound. A combination of magnetic resonance imaging and fluoroscopic guidance was used, to the best of our knowledge for the first time, to ablate the tumor with radiofrequency. The patient was cancer-free and off dialysis at 30-month follow up.

  18. Optical image segmentation using wavelet filtering techniques

    NASA Astrophysics Data System (ADS)

    Veronin, Christopher P.

    1990-12-01

    This research effort successfully implemented an automatic, optically based image segmentation scheme for locating potential targets in a cluttered FLIR image. Such a design is critical to achieve real-time segmentation and classification for machine vision applications. The segmentation scheme used in this research was based on texture discrimination and employs orientation specific, bandpass spatial filters as its main component. The orientation specific, bandpass spatial filters designed during this research include symmetrically located circular apertures implemented on heavy, black aluminum foil; cosine and sine Gabor filters implemented with detour-phase computer generated holography photoreduced onto glass slides; and symmetrically located circular apertures implemented on a liquid crystal television (LCTV) for real-time filter selection. The most successful design was the circular aperture pairs implemented on the aluminum foil. Segmentation was illustrated for simple and complex texture slides, glass template slides, and static and real-time FLIR imagery displayed on an LCTV.

  19. Multiwavelet-transform-based image compression techniques

    NASA Astrophysics Data System (ADS)

    Rao, Sathyanarayana S.; Yoon, Sung H.; Shenoy, Deepak

    1996-10-01

    Multiwavelet transforms are a new class of wavelet transforms that use more than one prototype scaling function and wavelet in the multiresolution analysis/synthesis. The popular Geronimo-Hardin-Massopust multiwavelet basis functions have properties of compact support, orthogonality, and symmetry which cannot be obtained simultaneously in scalar wavelets. The performance of multiwavelets in still image compression is studied using vector quantization of multiwavelet subbands with a multiresolution codebook. The coding gain of multiwavelets is compared with that of other well-known wavelet families using performance measures such as unified coding gain. Implementation aspects of multiwavelet transforms such as pre-filtering/post-filtering and symmetric extension are also considered in the context of image compression.

  20. Reconstruction Techniques for Sparse Multistatic Linear Array Microwave Imaging

    SciTech Connect

    Sheen, David M.; Hall, Thomas E.

    2014-06-09

    Sequentially-switched linear arrays are an enabling technology for a number of near-field microwave imaging applications. Electronically sequencing along the array axis followed by mechanical scanning along an orthogonal axis allows dense sampling of a two-dimensional aperture in near real-time. In this paper, a sparse multi-static array technique will be described along with associated Fourier-Transform-based and back-projection-based image reconstruction algorithms. Simulated and measured imaging results are presented that show the effectiveness of the sparse array technique along with the merits and weaknesses of each image reconstruction approach.

  1. Automated thermal mapping techniques using chromatic image analysis

    NASA Technical Reports Server (NTRS)

    Buck, Gregory M.

    1989-01-01

    Thermal imaging techniques are introduced using a chromatic image analysis system and temperature sensitive coatings. These techniques are used for thermal mapping and surface heat transfer measurements on aerothermodynamic test models in hypersonic wind tunnels. Measurements are made on complex vehicle configurations in a timely manner and at minimal expense. The image analysis system uses separate wavelength filtered images to analyze surface spectral intensity data. The system was initially developed for quantitative surface temperature mapping using two-color thermographic phosphors but was found useful in interpreting phase change paint and liquid crystal data as well.

  2. High-Resolution and Animal Imaging Instrumentation and Techniques

    NASA Astrophysics Data System (ADS)

    Belcari, Nicola; Guerra, AlbertoDel

    During the last decade we have observed a growing interest in "in vivo" imaging techniques for small animals. This is due to the necessity of studying biochemical processes at a molecular level for pharmacology, genetic, and pathology investigations. This field of research is usually called "molecular imaging."Advances in biological understanding have been accompanied by technological advances in instrumentation and techniques and image-reconstruction software, resulting in improved image quality, visibility, and interpretation. The main technological challenge is then the design of systems with high spatial resolution and high sensitivity.

  3. The application of image enhancement techniques to remote manipulator operation

    NASA Technical Reports Server (NTRS)

    Gonzalez, R. C.

    1974-01-01

    Methods of image enhancement which can be used by an operator who is not experienced with the mechanisms of enhancement to obtain satisfactory results were designed and implemented. Investigation of transformations which operate directly on the image domain resulted in a new technique of contrast enhancement. Transformations on the Fourier transform of the original image, including such techniques as homomorphic filtering, were also investigated. The methods of communication between the enhancement system and the computer operator were analyzed, and a language was developed for use in image enhancement. A working enhancement system was then created, and is included.

  4. Efficient imaging techniques using an ultrasonic array

    NASA Astrophysics Data System (ADS)

    Moreau, L.; Hunter, A. J.; Drinkwater, B. W.; Wilcox, P. D.

    2010-03-01

    Over the past few years, ultrasonic phased arrays have shown good potential for non-destructive testing (NDT), thanks to high resolution imaging algorithms that allow the characterization of defects in a structure. Many algorithms are based on the full matrix capture, obtained by firing each element of an ultrasonic array independently, while collecting the data with all elements. Because of the finite sound velocity in the specimen, two consecutive firings must be separated by a minimum time interval. Therefore, more elements in the array require longer data acquisition times. Moreover, if the array has N elements, then the full matrix contains N2 temporal signals to be processed. Because of the limited calculation speed of current computers, a large matrix of data can result in rather long post-processing times. In an industrial context where real-time imaging is desirable, it is crucial to reduce acquisition and/or post-processing times. This paper investigates methods designed to reduce acquisition and post-processing times for the TFM and wavenumber algorithms. To reduce data capture and post-processing, limited transmission cycles are used. Post-processing times is also further reduced by demodulating the data to baseband, which allows reducing the sampling rate of signals. Results are presented so that a compromise can be made between acquisition time, post-processing time and image quality. Possible improvement of images quality, using the effective aperture theory, is discussed. This has been implemented for the TFM but it still has to be developed for the wavenumber algorithm.

  5. Robust image modeling technique with a bioluminescence image segmentation application

    NASA Astrophysics Data System (ADS)

    Zhong, Jianghong; Wang, Ruiping; Tian, Jie

    2009-02-01

    A robust pattern classifier algorithm for the variable symmetric plane model, where the driving noise is a mixture of a Gaussian and an outlier process, is developed. The veracity and high-speed performance of the pattern recognition algorithm is proved. Bioluminescence tomography (BLT) has recently gained wide acceptance in the field of in vivo small animal molecular imaging. So that it is very important for BLT to how to acquire the highprecision region of interest in a bioluminescence image (BLI) in order to decrease loss of the customers because of inaccuracy in quantitative analysis. An algorithm in the mode is developed to improve operation speed, which estimates parameters and original image intensity simultaneously from the noise corrupted image derived from the BLT optical hardware system. The focus pixel value is obtained from the symmetric plane according to a more realistic assumption for the noise sequence in the restored image. The size of neighborhood is adaptive and small. What's more, the classifier function is base on the statistic features. If the qualifications for the classifier are satisfied, the focus pixel intensity is setup as the largest value in the neighborhood.Otherwise, it will be zeros.Finally,pseudo-color is added up to the result of the bioluminescence segmented image. The whole process has been implemented in our 2D BLT optical system platform and the model is proved.

  6. Employing image processing techniques for cancer detection using microarray images.

    PubMed

    Dehghan Khalilabad, Nastaran; Hassanpour, Hamid

    2017-02-01

    Microarray technology is a powerful genomic tool for simultaneously studying and analyzing the behavior of thousands of genes. The analysis of images obtained from this technology plays a critical role in the detection and treatment of diseases. The aim of the current study is to develop an automated system for analyzing data from microarray images in order to detect cancerous cases. The proposed system consists of three main phases, namely image processing, data mining, and the detection of the disease. The image processing phase performs operations such as refining image rotation, gridding (locating genes) and extracting raw data from images the data mining includes normalizing the extracted data and selecting the more effective genes. Finally, via the extracted data, cancerous cell is recognized. To evaluate the performance of the proposed system, microarray database is employed which includes Breast cancer, Myeloid Leukemia and Lymphomas from the Stanford Microarray Database. The results indicate that the proposed system is able to identify the type of cancer from the data set with an accuracy of 95.45%, 94.11%, and 100%, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Automated synthesis of image processing procedures using AI planning techniques

    NASA Technical Reports Server (NTRS)

    Chien, Steve; Mortensen, Helen

    1994-01-01

    This paper describes the Multimission VICAR (Video Image Communication and Retrieval) Planner (MVP) (Chien 1994) system, which uses artificial intelligence planning techniques (Iwasaki & Friedland, 1985, Pemberthy & Weld, 1992, Stefik, 1981) to automatically construct executable complex image processing procedures (using models of the smaller constituent image processing subprograms) in response to image processing requests made to the JPL Multimission Image Processing Laboratory (MIPL). The MVP system allows the user to specify the image processing requirements in terms of the various types of correction required. Given this information, MVP derives unspecified required processing steps and determines appropriate image processing programs and parameters to achieve the specified image processing goals. This information is output as an executable image processing program which can then be executed to fill the processing request.

  8. Biophotonics techniques for structural and functional imaging, in vivo.

    PubMed

    Ardeshirpour, Yasaman; Gandjbakhche, Amir H; Najafizadeh, Laleh

    2013-01-01

    In vivo optical imaging is being conducted in a variety of medical applications, including optical breast cancer imaging, functional brain imaging, endoscopy, exercise medicine, and monitoring the photodynamic therapy and progress of neoadjuvant chemotherapy. In the past three decades, in vivo diffuse optical breast cancer imaging has shown promising results in cancer detection, and monitoring the progress of neoadjuvant chemotherapy. The use of near infrared spectroscopy for functional brain imaging has been growing rapidly. In fluorescence imaging, the difference between autofluorescence of cancer lesions compared to normal tissues were used in endoscopy to distinguish malignant lesions from normal tissue or inflammation and in determining the boarders of cancer lesions in surgery. Recent advances in drugs targeting specific tumor receptors, such as monoclonal antibodies (mAb), has created a new demand for developing non-invasive in vivo imaging techniques for detection of cancer biomarkers, and for monitoring their down regulations during therapy. Targeted treatments, combined with new imaging techniques, are expected to potentially result in new imaging and treatment paradigms in cancer therapy. Similar approaches can potentially be applied for the characterization of other disease-related biomarkers. In this chapter, we provide a review of diffuse optical and fluorescence imaging techniques with their application in functional brain imaging and cancer diagnosis.

  9. Biophotonics techniques for structural and functional imaging, in vivo.

    PubMed

    Ardeshirpour, Yasaman; Gandjbakhche, Amir H; Najafizadeh, Laleh

    2012-01-01

    In vivo optical imaging is being conducted in a variety of medical applications, including optical breast cancer imaging, functional brain imaging, endoscopy, exercise medicine, and monitoring the photodynamic therapy and progress of neoadjuvant chemotherapy. In the past three decades, in vivo diffuse optical breast cancer imaging has shown promising results in cancer detection, and monitoring the progress of neoadjuvant chemotherapy. The use of near infrared spectroscopy for functional brain imaging has been growing rapidly. In fluorescence imaging, the difference between autofluorescence of cancer lesions compared to normal tissues were used in endoscopy to distinguish malignant lesions from normal tissue or inflammation and in determining the boarders of cancer lesions in surgery. Recent advances in drugs targeting specific tumor receptors, such as AntiBodies (MAB), has created a new demand for developing non-invasive in vivo imaging techniques for detection of cancer biomarkers, and for monitoring their down regulations during therapy. Targeted treatments, combined with new imaging techniques, are expected to potentially result in new imaging and treatment paradigms in cancer therapy. Similar approaches can potentially be applied for the characterization of other disease-related biomarkers. In this chapter, we provide a review of diffuse optical and fluorescence imaging techniques with their application in functional brain imaging and cancer diagnosis.

  10. Optical double image encryption employing a pseudo image technique in the Fourier domain

    NASA Astrophysics Data System (ADS)

    Guo, Changliang; Liu, Shi; Sheridan, John T.

    2014-06-01

    A novel optical encryption method is proposed involving double image encryption in which one image is introduced as the pseudo image while the other is the original object image. The Double Random Phase Encoding technique is used to encrypt both the pseudo and object images into complex images. A unique binary image is then employed to first generate the random phase key for the object image encryption and then to embed the encrypted object image into the encrypted pseudo image, which acts as host image. Both the second random phase mask used for encoding the pseudo image and the binary image act as encryption keys. If an attacker attempts to crack the random phase key and decrypt the original object image, the pseudo image will be obtained instead. Simulation results and robustness tests are performed which demonstrate the feasibility of the algorithm.

  11. "Relative CIR": an image enhancement and visualization technique

    USGS Publications Warehouse

    Fleming, Michael D.

    1993-01-01

    Many techniques exist to spectrally and spatially enhance digital multispectral scanner data. One technique enhances an image while keeping the colors as they would appear in a color-infrared (CIR) image. This "relative CIR" technique generates an image that is both spectrally and spatially enhanced, while displaying a maximum range of colors. The technique enables an interpreter to visualize either spectral or land cover classes by their relative CIR characteristics. A relative CIR image is generated by developed spectral statistics for each class in the classifications and then, using a nonparametric approach for spectral enhancement, the means of the classes for each band are ranked. A 3 by 3 pixel smoothing filter is applied to the classification for spatial enhancement and the classes are mapped to the representative rank for each band. Practical applications of the technique include displaying an image classification product as a CIR image that was not derived directly from a spectral image, visualizing how a land cover classification would look as a CIR image, and displaying a spectral classification or intermediate product that will be used to label spectral classes.

  12. Comparison of interferometric spectral imaging techniques near the pupil plane and image plane

    NASA Astrophysics Data System (ADS)

    Itoh, Kazuyoshi; Inoue, Takashi; Ichioka, Yoshiki

    1990-07-01

    We present an analysis of signal to noise ratios of two interferometric techniques for spectral imaging and its experimental verification. One technique makes use of interference signals detected near the pupil plane and the other uses the signals near the image plane. The experiments showed that the latter technique is superior to the former under the normal conditions. 1.

  13. Visualization of sound generation: special imaging techniques

    NASA Astrophysics Data System (ADS)

    Hahlweg, Cornelius F.; Skaloud, Daniel C.; Gutzmann, Holger L.; Kutz, Sascha; Rothe, Hendrik

    2013-09-01

    The present paper is dedicated to the Optics and Music session of the Novel Systems Design and Optimization XVI Conference. It is intended as an informative paper for the music enthusiasts. Included are some examples of visualization of sound generation and vibration modes of musically relevant objects and processes - record playback, an electric guitar and a wine glass - using high speed video, borescopic view and cross polarization techniques.

  14. New spectral imaging techniques for blood oximetry in the retina

    NASA Astrophysics Data System (ADS)

    Alabboud, Ied; Muyo, Gonzalo; Gorman, Alistair; Mordant, David; McNaught, Andrew; Petres, Clement; Petillot, Yvan R.; Harvey, Andrew R.

    2007-07-01

    Hyperspectral imaging of the retina presents a unique opportunity for direct and quantitative mapping of retinal biochemistry - particularly of the vasculature where blood oximetry is enabled by the strong variation of absorption spectra with oxygenation. This is particularly pertinent both to research and to clinical investigation and diagnosis of retinal diseases such as diabetes, glaucoma and age-related macular degeneration. The optimal exploitation of hyperspectral imaging however, presents a set of challenging problems, including; the poorly characterised and controlled optical environment of structures within the retina to be imaged; the erratic motion of the eye ball; and the compounding effects of the optical sensitivity of the retina and the low numerical aperture of the eye. We have developed two spectral imaging techniques to address these issues. We describe first a system in which a liquid crystal tuneable filter is integrated into the illumination system of a conventional fundus camera to enable time-sequential, random access recording of narrow-band spectral images. Image processing techniques are described to eradicate the artefacts that may be introduced by time-sequential imaging. In addition we describe a unique snapshot spectral imaging technique dubbed IRIS that employs polarising interferometry and Wollaston prism beam splitters to simultaneously replicate and spectrally filter images of the retina into multiple spectral bands onto a single detector array. Results of early clinical trials acquired with these two techniques together with a physical model which enables oximetry map are reported.

  15. Technique development for photoacoustic imaging guided interventions

    NASA Astrophysics Data System (ADS)

    Cheng, Qian; Zhang, Haonan; Yuan, Jie; Feng, Ting; Xu, Guan; Wang, Xueding

    2015-03-01

    Laser-induced thermotherapy (LITT), i.e. tissue destruction induced by a local increase of temperature by means of laser light energy transmission, has been frequently used for minimally invasive treatments of various diseases such as benign thyroid nodules and liver cancer. The emerging photoacoustic (PA) imaging, when integrated with ultrasound (US), could contribute to LITT procedure. PA can enable a good visualization of percutaneous apparatus deep inside tissue and, therefore, can offer accurate guidance of the optical fibers to the target tissue. Our initial experiment demonstrated that, by picking the strong photoacoustic signals generated at the tips of optical fibers as a needle, the trajectory and position of the fibers could be visualized clearly using a commercial available US unit. When working the conventional US Bscan mode, the fibers disappeared when the angle between the fibers and the probe surface was larger than 60 degree; while working on the new PA mode, the fibers could be visualized without any problem even when the angle between the fibers and the probe surface was larger than 75 degree. Moreover, with PA imaging function integrated, the optical fibers positioned into the target tissue, besides delivering optical energy for thermotherapy, can also be used to generate PA signals for on-line evaluation of LITT. Powered by our recently developed PA physio-chemical analysis, PA measurements from the tissue can provide a direct and accurate feedback of the tissue responses to laser ablation, including the changes in not only chemical compositions but also histological microstructures. The initial experiment on the rat liver model has demonstrated the excellent sensitivity of PA imaging to the changes in tissue temperature rise and tissue status (from native to coagulated) when the tissue is treated in vivo with LITT.

  16. Studies of EGRET sources with a novel image restoration technique

    SciTech Connect

    Tajima, Hiroyasu; Cohen-Tanugi, Johann; Kamae, Tuneyoshi; Finazzi, Stefano; Chiang, James

    2007-07-12

    We have developed an image restoration technique based on the Richardson-Lucy algorithm optimized for GLAST-LAT image analysis. Our algorithm is original since it utilizes the PSF (point spread function) that is calculated for each event. This is critical for EGRET and GLAST-LAT image analysis since the PSF depends on the energy and angle of incident gamma-rays and varies by more than one order of magnitude. EGRET and GLAST-LAT image analysis also faces Poisson noise due to low photon statistics. Our technique incorporates wavelet filtering to minimize noise effects. We present studies of EGRET sources using this novel image restoration technique for possible identification of extended gamma-ray sources.

  17. A fuzzy optimal threshold technique for medical images

    NASA Astrophysics Data System (ADS)

    Thirupathi Kannan, Balaji; Krishnasamy, Krishnaveni; Pradeep Kumar Kenny, S.

    2011-12-01

    A new fuzzy based thresholding method for medical images especially cervical cytology images having blob and mosaic structures is proposed in this paper. Many existing thresholding algorithms may segment either blob or mosaic images but there aren't any single algorithm that can do both. In this paper, an input cervical cytology image is binarized, preprocessed and the pixel value with minimum Fuzzy Gaussian Index is identified as an optimal threshold value and used for segmentation. The proposed technique is tested on various cervical cytology images having blob or mosaic structures, compared with various existing algorithms and proved better than the existing algorithms.

  18. A fuzzy optimal threshold technique for medical images

    NASA Astrophysics Data System (ADS)

    Thirupathi Kannan, Balaji; Krishnasamy, Krishnaveni; Pradeep Kumar Kenny, S.

    2012-01-01

    A new fuzzy based thresholding method for medical images especially cervical cytology images having blob and mosaic structures is proposed in this paper. Many existing thresholding algorithms may segment either blob or mosaic images but there aren't any single algorithm that can do both. In this paper, an input cervical cytology image is binarized, preprocessed and the pixel value with minimum Fuzzy Gaussian Index is identified as an optimal threshold value and used for segmentation. The proposed technique is tested on various cervical cytology images having blob or mosaic structures, compared with various existing algorithms and proved better than the existing algorithms.

  19. Optical and digital microscopic imaging techniques and applications in pathology.

    PubMed

    Chen, Xiaodong; Zheng, Bin; Liu, Hong

    2011-01-01

    The conventional optical microscope has been the primary tool in assisting pathological examinations. The modern digital pathology combines the power of microscopy, electronic detection, and computerized analysis. It enables cellular-, molecular-, and genetic-imaging at high efficiency and accuracy to facilitate clinical screening and diagnosis. This paper first reviews the fundamental concepts of microscopic imaging and introduces the technical features and associated clinical applications of optical microscopes, electron microscopes, scanning tunnel microscopes, and fluorescence microscopes. The interface of microscopy with digital image acquisition methods is discussed. The recent developments and future perspectives of contemporary microscopic imaging techniques such as three-dimensional and in vivo imaging are analyzed for their clinical potentials.

  20. Integrated contour detection and pose estimation for fluoroscopic analysis of knee implants.

    PubMed

    Prins, A H; Kaptein, B L; Stoel, B C; Nelissen, R G H H; Reiber, J H C; Valstar, E R

    2011-08-01

    With fluoroscopic analysis of knee implant kinematics the implant contour must be detected in each image frame, followed by estimation of the implant pose. With a large number of possibly low-quality images, the contour detection is a time-consuming bottleneck. The present paper proposes an automated contour detection method, which is integrated in the pose estimation. In a phantom experiment the automated method was compared with a standard method, which uses manual selection of correct contour parts. Both methods demonstrated comparable precision, with a minor difference in the Y-position (0.08 mm versus 0.06 mm). The precision of each method was so small (below 0.2 mm and 0.3 degrees) that both are sufficiently accurate for clinical research purposes. The efficiency of both methods was assessed on six clinical datasets. With the automated method the observer spent 1.5 min per image, significantly less than 3.9 min with the standard method. A Bland-Altman analysis between the methods demonstrated no discernible trends in the relative femoral poses. The threefold increase in efficiency demonstrates that a pose estimation approach with integrated contour detection is more intuitive than a standard method. It eliminates most of the manual work in fluoroscopic analysis, with sufficient precision for clinical research purposes.

  1. A moving slanted-edge method to measure the temporal modulation transfer function of fluoroscopic systems

    SciTech Connect

    Friedman, S. N.; Cunningham, I. A.

    2008-06-15

    Lag in fluoroscopic systems introduces a frame-averaging effect that reduces measurements of image noise and incorrectly inflates measurements of the detective quantum efficiency (DQE). A correction can be implemented based on measurements of the temporal modulation transfer function (MTF). We introduce a method of measuring the temporal MTF under fluoroscopic conditions using a moving slanted edge, a generalization of the slanted-edge method used to measure the (spatial) MTF, providing the temporal MTF of the entire imaging system. The method uses a single x-ray exposure, constant edge velocity, and assumes spatial and temporal blurring are separable. The method was validated on a laboratory x-ray image intensifier (XRII) system by comparison with direct measurements of the XRII optical response, showing excellent agreement over the entire frequency range tested ({+-}100 Hz). With proper access to linearized data and continuous fluoroscopy, this method can be implemented in a clinical setting on both XRII and flat-panel detectors. It is shown that the temporal MTF of the CsI-based validation system is a function of exposure rate. The rising-edge response showed more lag than the falling edge, and the temporal MTF decreased with decreasing exposure rate. It is suggested that a small-signal approach, in which the range of exposure rates is restricted to a linear range by using a semitransparent moving edge, would be appropriate for measuring the DQE of these systems.

  2. Intraoperative fluoroscopic assessment of proper prosthetic radial head height.

    PubMed

    Kim, H Mike; Roush, Evan P; Kiser, Casey

    2016-11-01

    Selecting a properly sized radial head prosthesis is imperative during radial head replacement. Although there has been much emphasis on avoiding overlengthening of the radius, little has been studied about how to avoid shortening. The purpose of this study was to characterize how a radial head replacement appears on intraoperative fluoroscopy depending on the height of the prosthetic radial head. Articular cartilage thickness of the radial head was measured in 9 cadaveric elbows. Radial head replacement was performed in each specimen with 4 different prosthetic head heights: 4 mm and 2 mm shortening, anatomic, and 2 mm overlengthening. Anteroposterior fluoroscopic images were obtained for each head height, and the prosthetic radial head height was measured at 3 forearm positions (supination, neutral, and pronation) using the subchondral bone of the lateral edge of the coronoid at the reference point. The mean cartilage thickness of the radial head was 1.3 ± 0.4 mm. The prosthetic radial head appeared 2.2 ± 0.4 mm more proximal than the subchondral bone of the coronoid lateral edge in anteroposterior radiographs when the articular surface of the prosthesis was completely even with the coronoid articular surface. Unlike the native radial head, a prosthetic radial head showed a significant change of height with different forearm rotation (P < .001). This study found that a perfectly anatomic radial head replacement appears overlengthened by approximately 2 mm in intraoperative radiographs. This finding can be useful in guiding the appropriate height of a prosthetic radial head. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  3. Magnetic resonance image segmentation using multifractal techniques

    NASA Astrophysics Data System (ADS)

    Yu, Yue-e.; Wang, Fang; Liu, Li-lin

    2015-11-01

    In order to delineate target region for magnetic resonance image (MRI) with diseases, the classical multifractal spectrum (MFS)-segmentation method and latest multifractal detrended fluctuation spectrum (MF-DFS)-based segmentation method are employed in our study. One of our main conclusions from experiments is that both of the two multifractal-based methods are workable for handling MRIs. The best result is obtained by MF-DFS-based method using Lh10 as local characteristic. The anti-noises experiments also suppot the conclusion. This interest finding shows that the features can be better represented by the strong fluctuations instead of the weak fluctuations for the MRIs. By comparing the multifractal nature between lesion and non-lesion area on the basis of the segmentation results, an interest finding is that the gray value's fluctuation in lesion area is much severer than that in non-lesion area.

  4. Advanced millimeter-wave security portal imaging techniques

    NASA Astrophysics Data System (ADS)

    Sheen, David M.; Bernacki, Bruce E.; McMakin, Douglas L.

    2012-03-01

    Millimeter-wave (mm-wave) imaging is rapidly gaining acceptance as a security tool to augment conventional metal detectors and baggage x-ray systems for passenger screening at airports and other secured facilities. This acceptance indicates that the technology has matured; however, many potential improvements can yet be realized. The authors have developed a number of techniques over the last several years including novel image reconstruction and display techniques, polarimetric imaging techniques, array switching schemes, and high-frequency high-bandwidth techniques. All of these may improve the performance of new systems; however, some of these techniques will increase the cost and complexity of the mm-wave security portal imaging systems. Reducing this cost may require the development of novel array designs. In particular, RF photonic methods may provide new solutions to the design and development of the sequentially switched linear mm-wave arrays that are the key element in the mm-wave portal imaging systems. Highfrequency, high-bandwidth designs are difficult to achieve with conventional mm-wave electronic devices, and RF photonic devices may be a practical alternative. In this paper, the mm-wave imaging techniques developed at PNNL are reviewed and the potential for implementing RF photonic mm-wave array designs is explored.

  5. Investigations of Antiangiogenic Mechanisms Using Novel Imaging Techniques

    DTIC Science & Technology

    2011-02-01

    Wilson, “ Intravital high-resolution optical imaging of individual vessel re- sponse to photodynamic treatment,” J. Biomed. Opt. 134, 040502 2008. 7...nanoparticles ∼80–100 nm diam. 1.2 Microscope A Zeiss MPS intravital microscope was used for all imaging , using a 2.5X objective. A DAPI excitation filter...Jan 2011 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER BC083195 Investigation of Antiangiogenic Mechanisms Using Novel Imaging Techniques 5b

  6. Development of Digital Steroscopic Imaging Technique in Mammography

    DTIC Science & Technology

    2001-05-01

    imaging technique in which the phantom was shifted instead of the focal spot for acquisition of the left-eye and right-eye images. In a preliminary observer... Phantoms (C) Phantom Evaluation of Full Field Steremammography (D) Evaluation of the Effect of Zooming on Depth Measurements in Digital...interpretation by radiologists and reduce unnecessary biopsies. To accomplish this goal, we first performed phantom studies to develop an optimal imaging

  7. Reconstruction techniques for sparse multistatic linear array microwave imaging

    NASA Astrophysics Data System (ADS)

    Sheen, David M.; Hall, Thomas E.

    2014-06-01

    Sequentially-switched linear arrays are an enabling technology for a number of near-field microwave imaging applications. Electronically sequencing along the array axis followed by mechanical scanning along an orthogonal axis allows dense sampling of a two-dimensional aperture in near real-time. The Pacific Northwest National Laboratory (PNNL) has developed this technology for several applications including concealed weapon detection, groundpenetrating radar, and non-destructive inspection and evaluation. These techniques form three-dimensional images by scanning a diverging beam swept frequency transceiver over a two-dimensional aperture and mathematically focusing or reconstructing the data into three-dimensional images. Recently, a sparse multi-static array technology has been developed that reduces the number of antennas required to densely sample the linear array axis of the spatial aperture. This allows a significant reduction in cost and complexity of the linear-array-based imaging system. The sparse array has been specifically designed to be compatible with Fourier-Transform-based image reconstruction techniques; however, there are limitations to the use of these techniques, especially for extreme near-field operation. In the extreme near-field of the array, back-projection techniques have been developed that account for the exact location of each transmitter and receiver in the linear array and the 3-D image location. In this paper, the sparse array technique will be described along with associated Fourier-Transform-based and back-projection-based image reconstruction algorithms. Simulated imaging results are presented that show the effectiveness of the sparse array technique along with the merits and weaknesses of each image reconstruction approach.

  8. Cell imaging techniques based on digital image plane holography

    NASA Astrophysics Data System (ADS)

    Chen, Zhaoji; Gong, Wendi; Liu, Feifei; Wang, Huaying

    2010-11-01

    This paper has further studied the implementation methods and recording conditions of digital microscopic image plane holography (DMIPH). Two optical systems of DMIPH were built: one is recording hologram by using plane waves as reference light, the other is recording hologram by spherical reference light. Breast cancer cells and USAF resolution test target is used as tested samples in the experiment. Then the intensity distribution and three-dimensional shape information of the cells are got accurately. The experiment results show that DMIPH avoids the process of finding recording distance by using auto-focusing approach. The recording and reconstruction process of DMIPH is simple. Therefore DMIPH can be applied to the microscopic imaging of cells more effectively.

  9. Application of digital image processing techniques to astronomical imagery 1978

    NASA Technical Reports Server (NTRS)

    Lorre, J. J.

    1978-01-01

    Techniques for using image processing in astronomy are identified and developed for the following: (1) geometric and radiometric decalibration of vidicon-acquired spectra, (2) automatic identification and segregation of stars from galaxies; and (3) display of multiband radio maps in compact and meaningful formats. Examples are presented of these techniques applied to a variety of objects.

  10. Using image processing techniques on proximity probe signals in rotordynamics

    NASA Astrophysics Data System (ADS)

    Diamond, Dawie; Heyns, Stephan; Oberholster, Abrie

    2016-06-01

    This paper proposes a new approach to process proximity probe signals in rotordynamic applications. It is argued that the signal be interpreted as a one dimensional image. Existing image processing techniques can then be used to gain information about the object being measured. Some results from one application is presented. Rotor blade tip deflections can be calculated through localizing phase information in this one dimensional image. It is experimentally shown that the newly proposed method performs more accurately than standard techniques, especially where the sampling rate of the data acquisition system is inadequate by conventional standards.

  11. The Advanced Space Plant Culture Device with Live Imaging Technique

    NASA Astrophysics Data System (ADS)

    Zheng, Weibo; Zhang, Tao; Tong, Guanghui

    The live imaging techniques, including the color and fluorescent imags, are very important and useful for space life science. The advanced space plant culture Device (ASPCD) with live imaging Technique, developed for Chinese Spacecraft, would be introduced in this paper. The ASPCD had two plant experimental chambers. Three cameras (two color cameras and one fluorescent camera) were installed in the two chambers. The fluorescent camera could observe flowering genes, which were labeled by GFP. The lighting, nutrient, temperature controling and water recycling were all independent in each chamber. The ASPCD would beed applied to investigate for the growth and development of the high plant under microgravity conditions on board the Chinese Spacecraft.

  12. A fast iterative technique for restoring scanning electron microscope images

    NASA Astrophysics Data System (ADS)

    Nakahira, Kenji; Miyamoto, Atsushi; Honda, Toshifumi

    2014-12-01

    This paper proposes a fast new technique for restoring scanning electron microscope images to improve their sharpness. The images with our approach are sharpened by deconvolution with the point spread function modeled as the intensity distribution of the electron beam at the specimen's surface. We propose an iterative technique that employs a modified cost function based on the Richardson-Lucy method to achieve faster processing. The empirical results indicate significant improvements in image quality. The proposed approach speeds up deconvolution by about 10-50 times faster than that with the conventional Richardson-Lucy method.

  13. A novel Region of Interest (ROI) imaging technique for biplane imaging in interventional suites: high-resolution small field-of-view imaging in the frontal plane and dose-reduced, large field-of-view standard-resolution imaging in the lateral plane.

    PubMed

    Swetadri Vasan, S N; Ionita, C; Bednarek, D R; Rudin, S

    2014-03-19

    Endovascular-Image-Guided-Interventional (EIGI) treatment of neuro-vascular conditions such as aneurysms, stenosed arteries, and vessel thrombosis make use of treatment devices such as stents, coils, and balloons which have very small feature sizes, 10's of microns to a few 100's of microns, and hence demand a high resolution imaging system. The current state-of-the-art flat panel detector (FPD) has about a 200-um pixel size with the Nyquist of 2.5 lp/mm. For higher-resolution imaging a charge-coupled device (CCD) based Micro-Angio -Fluoroscope (MAF-CCD) with a pixel size of 35um (Nyquist of 11 lp/mm) was developed and previously reported. Although the detector addresses the high resolution needs, the Field-Of-View (FOV) is limited to 3.5 cm × 3.5 cm, which is much smaller than current FPDs. During the use of the MAF-CCD for delicate parts of the intervention, it may be desirable to have real-time monitoring outside the MAF FOV with a low dose, and lower, but acceptable, quality image. To address this need, a novel imaging technique for biplane imaging systems has been developed, using an MAF-CCD in the frontal plane and a dose-reduced standard large FOV imager in the lateral plane. The dose reduction is achieved by using a combination of ROI fluoroscopy and spatially different temporal filtering, a technique that has been previously presented. In order to evaluate this technique, a simulation using images acquired during an actual EIGI treatment on a patient, followed by an actual implementation on phantoms is presented.

  14. A novel Region of Interest (ROI) imaging technique for biplane imaging in interventional suites: high-resolution small field-of-view imaging in the frontal plane and dose-reduced, large field-of-view standard-resolution imaging in the lateral plane

    PubMed Central

    Swetadri Vasan, S.N; Ionita, C.; Bednarek, D.R; Rudin, S.

    2014-01-01

    Endovascular-Image-Guided-Interventional (EIGI) treatment of neuro-vascular conditions such as aneurysms, stenosed arteries, and vessel thrombosis make use of treatment devices such as stents, coils, and balloons which have very small feature sizes, 10's of microns to a few 100's of microns, and hence demand a high resolution imaging system. The current state-of-the-art flat panel detector (FPD) has about a 200-um pixel size with the Nyquist of 2.5 lp/mm. For higher-resolution imaging a charge-coupled device (CCD) based Micro-Angio -Fluoroscope (MAF-CCD) with a pixel size of 35um (Nyquist of 11 lp/mm) was developed and previously reported. Although the detector addresses the high resolution needs, the Field-Of-View (FOV) is limited to 3.5 cm × 3.5 cm, which is much smaller than current FPDs. During the use of the MAF-CCD for delicate parts of the intervention, it may be desirable to have real-time monitoring outside the MAF FOV with a low dose, and lower, but acceptable, quality image. To address this need, a novel imaging technique for biplane imaging systems has been developed, using an MAF-CCD in the frontal plane and a dose-reduced standard large FOV imager in the lateral plane. The dose reduction is achieved by using a combination of ROI fluoroscopy and spatially different temporal filtering, a technique that has been previously presented. In order to evaluate this technique, a simulation using images acquired during an actual EIGI treatment on a patient, followed by an actual implementation on phantoms is presented. PMID:25302001

  15. A novel Region of Interest (ROI) imaging technique for biplane imaging in interventional suites: high-resolution small field-of-view imaging in the frontal plane and dose-reduced, large field-of-view standard-resolution imaging in the lateral plane

    NASA Astrophysics Data System (ADS)

    Swetadri Vasan, Setlur Nagesh; Ionita, C.; Bednarek, D. R.; Rudin, Stephen

    2014-03-01

    Endovascular-Image-Guided-Interventional (EIGI) treatment of neuro-vascular conditions such as aneurysms, stenosed arteries, and vessel thrombosis make use of treatment devices such as stents, coils, and balloons which have very small feature sizes, 10's of microns to a few 100's of microns, and hence demand a high resolution imaging system. The current state-of-the-art flat panel detector (FPD) has about a 200-um pixel size with the Nyquist of 2.5 lp/mm. For higher-resolution imaging a charge-coupled device (CCD) based Micro-Angio - Fluoroscope (MAF-CCD) with a pixel size of 35um (Nyquist of 11 lp/mm) was developed and previously reported. Although the detector addresses the high resolution needs, the Field-Of-View (FOV) is limited to 3.5 cm x 3.5 cm, which is much smaller than current FPDs. During the use of the MAF-CCD for delicate parts of the intervention, it may be desirable to have real-time monitoring outside the MAF FOV with a low dose, and lower, but acceptable, quality image. To address this need, a novel imaging technique for biplane imaging systems has been developed, using an MAFCCD in the frontal plane and a dose-reduced standard large FOV imager in the lateral plane. The dose reduction is achieved by using a combination of ROI fluoroscopy and spatially different temporal filtering, a technique that has been previously presented. In order to evaluate this technique, a simulation using images acquired during an actual EIGI treatment on a patient, followed by an actual implementation on phantoms is presented.

  16. 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.

  17. Imaging techniques applied to characterize bitumen and bituminous emulsions.

    PubMed

    Rodríguez-Valverde, M A; Ramón-Torregrosa, P; Páez-Dueñas, A; Cabrerizo-Vílchez, M A; Hidalgo-Alvarez, R

    2008-01-15

    The purpose of this article is to present some important advances in the imaging techniques currently used in the characterization of bitumen and bituminous emulsions. Bitumen exhibits some properties, such as a black colour and a reflecting surface at rest, which permit the use of optical techniques to study the macroscopic behaviour of asphalt mixes in the cold mix technology based on emulsion use. Imaging techniques allow monitoring in situ the bitumen thermal sensitivity as well as the complex phenomenon of emulsion breaking. Evaporation-driven breaking was evaluated from the shape of evaporating emulsion drops deposited onto non-porous and hydrophobic substrates. To describe the breaking kinetics, top-view images of a drying emulsion drop placed on an aggregate sheet were acquired and processed properly. We can conclude that computer-aided image analysis in road pavement engineering can elucidate the mechanism of breaking and curing of bituminous emulsion.

  18. Digital imaging techniques for dental alloy castability quantification.

    PubMed

    Cohen, S M; Vaidyanathan, T K; Tanabe, N

    1992-05-01

    In this study, mesh monitors cast from experimental compositions of a Ni-Cr-Be alloy are evaluated by the application of image analysis techniques. Castability values obtained by this method are then contrasted with those from three commonly employed manual counting procedures. While castability values obtained by all methods reflect the effect of compositional variations, a comparison of results with respect to evaluation method indicates that the image analysis technique consistently yields higher castability values, especially evident in the poorly casting groups. The apparent explanation for these observed differences is that with imaging, segments that are partially cast to varying degrees are not arbitrarily eliminated from the data, as is the usual practice in manual counting methods; therefore, castability values obtained by using the imaging technique will very closely reflect an actual alloy volume of each cast monitor.

  19. Fluoroscopically guided extraforaminal cervical nerve root blocks: analysis of epidural flow of the injectate with respect to needle tip position.

    PubMed

    Shipley, Kyle; Riew, K Daniel; Gilula, Louis A

    2014-02-01

    Study Design Retrospective evaluation of consecutively performed fluoroscopically guided cervical nerve root blocks. Objective To describe the incidence of injectate central epidural flow with respect to needle tip position during fluoroscopically guided extraforaminal cervical nerve root blocks (ECNRBs). Methods Between February 19, 2003 and June 11, 2003, 132 consecutive fluoroscopically guided ECNRBs performed with contrast media in the final injected material (injectate) were reviewed on 95 patients with average of 1.3 injections per patient. Fluoroscopic spot images documenting the procedure were obtained as part of standard quality assurance. An independent observer not directly involved in the procedures retrospectively reviewed the images, and the data were placed into a database. Image review was performed to determine optimal needle tip positioning for injectate epidural flow. Results Central epidural injectate flow was obtained in only 28.9% of injections with the needle tip lateral to midline of the lateral mass (zone 2). 83.8% of injectate went into epidural space when the needle tip was medial to midline of the lateral mass (zone 3). 100% of injectate flowed epidurally when the needle tip was medial to or at the medial cortex of the lateral mass (zone 4). There was no statistically significant difference with regards to central epidural flow and the needle tip position on lateral view. Conclusion To ensure central epidural flow with ECNRBs one must be prepared to pass the needle tip medial to midplane of the lateral mass or to medial cortex of the lateral mass. Approximately 16% of ECNRBs with needle tip medial to midline of the lateral mass did not flow into epidural space. One cannot claim a nerve block is an epidural block unless epidural flow of injectate is observed.

  20. Vascular image registration techniques: A living review.

    PubMed

    Matl, Stefan; Brosig, Richard; Baust, Maximilian; Navab, Nassir; Demirci, Stefanie

    2017-01-01

    Registration of vascular structures is crucial for preoperative planning, intraoperative navigation, and follow-up assessment. Typical applications include, but are not limited to, Trans-catheter Aortic Valve Implantation and monitoring of tumor vasculature or aneurysm growth. In order to achieve the aforementioned goals, a large number of various registration algorithms has been developed. With this review paper we provide a comprehensive overview over the plethora of existing techniques with a particular focus on the suitable classification criteria such as the involved modalities of the employed optimization methods. However, we wish to go beyond a static literature review which is naturally doomed to be outdated after a certain period of time due to the research progress. We augment this review paper with an extendable and interactive database in order to obtain a living review whose currency goes beyond the one of a printed paper. All papers in this database are labeled with one or multiple tags according to 13 carefully defined categories. The classification of all entries can then be visualized as one or multiple trees which are presented via a web-based interactive app (http://livingreview.in.tum.de) allowing the user to choose a unique perspective for literature review. In addition, the user can search the underlying database for specific tags or publications related to vessel registration. Many applications of this framework are conceivable, including the use for getting a general overview on the topic or the utilization by physicians for deciding about the best-suited algorithm for a specific application.

  1. Minimax Techniques For Optimizing Non-Linear Image Algebra Transforms

    NASA Astrophysics Data System (ADS)

    Davidson, Jennifer L.

    1989-08-01

    It has been well established that the Air Force Armament Technical Laboratory (AFATL) image algebra is capable of expressing all linear transformations [7]. The embedding of the linear algebra in the image algebra makes this possible. In this paper we show a relation of the image algebra to another algebraic system called the minimax algebra. This system is used extensively in economics and operations research, but until now has not been investigated for applications to image processing. The relationship is exploited to develop new optimization methods for a class of non-linear image processing transforms. In particular, a general decomposition technique for templates in this non-linear domain is presented. Template decomposition techniques are an important tool in mapping algorithms efficiently to both sequential and massively parallel architectures.

  2. Computational ghost imaging: advanced compressive sensing (CS) technique

    NASA Astrophysics Data System (ADS)

    Katkovnik, Vladimir; Astola, Jaakko

    2012-10-01

    A novel efficient variational technique for speckle imaging is discussed. It is developed with the main motivation to filter noise, to wipe out the typical diffraction artifacts and to achieve crisp imaging. A sparse modeling is used for the wave field at the object plane in order to overcome the loss of information due to the ill-posedness of forward propagation image formation operators. This flexible and data adaptive modeling relies on the recent progress in sparse imaging and compressive sensing (CS). Being in line with the general formalism of CS, we develop an original approach to wave field reconstruction.7 In this paper we demonstrate this technique in its application for computational amplitude ghost imaging (GI), where a spatial light modulator (SLM) is used in order to generate a speckle wave field sensing a transmitted mask object.

  3. An image morphing technique based on optimal mass preserving mapping.

    PubMed

    Zhu, Lei; Yang, Yan; Haker, Steven; Tannenbaum, Allen

    2007-06-01

    Image morphing, or image interpolation in the time domain, deals with the metamorphosis of one image into another. In this paper, a new class of image morphing algorithms is proposed based on the theory of optimal mass transport. The L(2) mass moving energy functional is modified by adding an intensity penalizing term, in order to reduce the undesired double exposure effect. It is an intensity-based approach and, thus, is parameter free. The optimal warping function is computed using an iterative gradient descent approach. This proposed morphing method is also extended to doubly connected domains using a harmonic parameterization technique, along with finite-element methods.

  4. An Image Morphing Technique Based on Optimal Mass Preserving Mapping

    PubMed Central

    Zhu, Lei; Yang, Yan; Haker, Steven; Tannenbaum, Allen

    2013-01-01

    Image morphing, or image interpolation in the time domain, deals with the metamorphosis of one image into another. In this paper, a new class of image morphing algorithms is proposed based on the theory of optimal mass transport. The L2 mass moving energy functional is modified by adding an intensity penalizing term, in order to reduce the undesired double exposure effect. It is an intensity-based approach and, thus, is parameter free. The optimal warping function is computed using an iterative gradient descent approach. This proposed morphing method is also extended to doubly connected domains using a harmonic parameterization technique, along with finite-element methods. PMID:17547128

  5. Digital subtraction angiography: principles and pitfalls of image improvement techniques.

    PubMed

    Levin, D C; Schapiro, R M; Boxt, L M; Dunham, L; Harrington, D P; Ergun, D L

    1984-09-01

    The technology of imaging methods in digital subtraction angiography (DSA) is discussed in detail. Areas covered include function of the video camera in both interlaced and sequential scan modes, digitization by the analog-to-digital converter, logarithmic signal processing, dose rates, and acquisition of images using frame integration and pulsed-sequential techniques. Also discussed are various methods of improving image content and quality by both hardware and software modifications. These include the development of larger image intensifiers, larger matrices, video camera improvements, reregistration, hybrid subtraction, matched filtering, recursive filtering, DSA tomography, and edge enhancement.

  6. A new x-ray imaging technique for radiography mode of flat-panel imager

    NASA Astrophysics Data System (ADS)

    Suzuki, K.; Ikeda, S.; Ueda, K.; Baba, R.

    2007-03-01

    A digital radiography system using a flat-panel imager, which has a novel imaging technique for a radiography mode, has been developed. A radiographic image captured by the new imaging technique has a wide dynamic range in comparison with conventional radiographic images. The purpose of this presentation is to show the basic performance of the image quality acquired by the new imaging technique and compare it with an image taken by a conventional technique. The flat-panel imager has a gain switching capability, normally used in a dynamic imaging mode for a cone-beam CT study. The gain switching method has two gain settings and switches between them automatically, depending on the incident dose to each pixel of flat-panel imager. As a result of the gain switching method, an image having wide dynamic range is achieved. In this study, we applied the gain switching method to the radiography mode, and achieved a radiographic image with wider dynamic range than a conventional radiograph. Furthermore, we have also developed an algorithm for calibration of the gain switching method in radiography mode.

  7. [Novel endoscopic techniques to image the upper gastrointestinal tract].

    PubMed

    Quénéhervé, Lucille; Neunlist, Michel; Bruley des Varannes, Stanislas; Tearney, Guillermo; Coron, Emmanuel

    2015-01-01

    Novel endoscopic techniques for the analysis of the digestive wall have recently been developed to allow investigating digestive diseases beyond standard "white-light" macroscopic imaging of the mucosal surface. Among innovative techniques under clinical evaluation, confocal endomicroscopy and optical frequency domain imaging (OFDI) are the most promising. Indeed, these techniques allow performing in vivo microscopy with different levels in terms of depths and magnification, as well as functional assessment of structures. Some of these techniques, such as capsule-based OFDI, are also less invasive than traditional endoscopy and might help screening large groups of patients for specific disorders, for instance oesophageal precancerous diseases. In this review, we will focus on the results obtained with these techniques in precancerous, inflammatory and neuromuscular disorders.

  8. 3D thermography imaging standardization technique for inflammation diagnosis

    NASA Astrophysics Data System (ADS)

    Ju, Xiangyang; Nebel, Jean-Christophe; Siebert, J. Paul

    2005-01-01

    We develop a 3D thermography imaging standardization technique to allow quantitative data analysis. Medical Digital Infrared Thermal Imaging is very sensitive and reliable mean of graphically mapping and display skin surface temperature. It allows doctors to visualise in colour and quantify temperature changes in skin surface. The spectrum of colours indicates both hot and cold responses which may co-exist if the pain associate with an inflammatory focus excites an increase in sympathetic activity. However, due to thermograph provides only qualitative diagnosis information, it has not gained acceptance in the medical and veterinary communities as a necessary or effective tool in inflammation and tumor detection. Here, our technique is based on the combination of visual 3D imaging technique and thermal imaging technique, which maps the 2D thermography images on to 3D anatomical model. Then we rectify the 3D thermogram into a view independent thermogram and conform it a standard shape template. The combination of these imaging facilities allows the generation of combined 3D and thermal data from which thermal signatures can be quantified.

  9. Comparison of lossless compression techniques for prepress color images

    NASA Astrophysics Data System (ADS)

    Van Assche, Steven; Denecker, Koen N.; Philips, Wilfried R.; Lemahieu, Ignace L.

    1998-12-01

    In the pre-press industry color images have both a high spatial and a high color resolution. Such images require a considerable amount of storage space and impose long transmission times. Data compression is desired to reduce these storage and transmission problems. Because of the high quality requirements in the pre-press industry only lossless compression is acceptable. Most existing lossless compression schemes operate on gray-scale images. In this case the color components of color images must be compressed independently. However, higher compression ratios can be achieved by exploiting inter-color redundancies. In this paper we present a comparison of three state-of-the-art lossless compression techniques which exploit such color redundancies: IEP (Inter- color Error Prediction) and a KLT-based technique, which are both linear color decorrelation techniques, and Interframe CALIC, which uses a non-linear approach to color decorrelation. It is shown that these techniques are able to exploit color redundancies and that color decorrelation can be done effectively and efficiently. The linear color decorrelators provide a considerable coding gain (about 2 bpp) on some typical prepress images. The non-linear interframe CALIC predictor does not yield better results, but the full interframe CALIC technique does.

  10. Pattern recognition software and techniques for biological image analysis.

    PubMed

    Shamir, Lior; Delaney, John D; Orlov, Nikita; Eckley, D Mark; Goldberg, Ilya G

    2010-11-24

    The increasing prevalence of automated image acquisition systems is enabling new types of microscopy experiments that generate large image datasets. However, there is a perceived lack of robust image analysis systems required to process these diverse datasets. Most automated image analysis systems are tailored for specific types of microscopy, contrast methods, probes, and even cell types. This imposes significant constraints on experimental design, limiting their application to the narrow set of imaging methods for which they were designed. One of the approaches to address these limitations is pattern recognition, which was originally developed for remote sensing, and is increasingly being applied to the biology domain. This approach relies on training a computer to recognize patterns in images rather than developing algorithms or tuning parameters for specific image processing tasks. The generality of this approach promises to enable data mining in extensive image repositories, and provide objective and quantitative imaging assays for routine use. Here, we provide a brief overview of the technologies behind pattern recognition and its use in computer vision for biological and biomedical imaging. We list available software tools that can be used by biologists and suggest practical experimental considerations to make the best use of pattern recognition techniques for imaging assays.

  11. Pattern Recognition Software and Techniques for Biological Image Analysis

    PubMed Central

    Shamir, Lior; Delaney, John D.; Orlov, Nikita; Eckley, D. Mark; Goldberg, Ilya G.

    2010-01-01

    The increasing prevalence of automated image acquisition systems is enabling new types of microscopy experiments that generate large image datasets. However, there is a perceived lack of robust image analysis systems required to process these diverse datasets. Most automated image analysis systems are tailored for specific types of microscopy, contrast methods, probes, and even cell types. This imposes significant constraints on experimental design, limiting their application to the narrow set of imaging methods for which they were designed. One of the approaches to address these limitations is pattern recognition, which was originally developed for remote sensing, and is increasingly being applied to the biology domain. This approach relies on training a computer to recognize patterns in images rather than developing algorithms or tuning parameters for specific image processing tasks. The generality of this approach promises to enable data mining in extensive image repositories, and provide objective and quantitative imaging assays for routine use. Here, we provide a brief overview of the technologies behind pattern recognition and its use in computer vision for biological and biomedical imaging. We list available software tools that can be used by biologists and suggest practical experimental considerations to make the best use of pattern recognition techniques for imaging assays. PMID:21124870

  12. Rock type discrimination techniques using Landsat and Seasat image data

    NASA Technical Reports Server (NTRS)

    Blom, R.; Abrams, M.; Conrad, C.

    1981-01-01

    Results of a sedimentary rock type discrimination project using Seasat radar and Landsat multispectral image data of the San Rafael Swell, in eastern Utah, are presented, which has the goal of determining the potential contribution of radar image data to Landsat image data for rock type discrimination, particularly when the images are coregistered. The procedure employs several images processing techniques using the Landsat and Seasat data independently, and then both data sets are coregistered. The images are evaluated according to the ease with which contacts can be located and rock units (not just stratigraphically adjacent ones) separated. Results show that of the Landsat images evaluated, the image using a supervised classification scheme is the best for sedimentary rock type discrimination. Of less value, in decreasing order, are color ratio composites, principal components, and the standard color composite. In addition, for rock type discrimination, the black and white Seasat image is less useful than any of the Landsat color images by itself. However, it is found that the incorporation of the surface textural measures made from the Seasat image provides a considerable and worthwhile improvement in rock type discrimination.

  13. Rock type discrimination techniques using Landsat and Seasat image data

    NASA Technical Reports Server (NTRS)

    Blom, R.; Abrams, M.; Conrad, C.

    1981-01-01

    Results of a sedimentary rock type discrimination project using Seasat radar and Landsat multispectral image data of the San Rafael Swell, in eastern Utah, are presented, which has the goal of determining the potential contribution of radar image data to Landsat image data for rock type discrimination, particularly when the images are coregistered. The procedure employs several images processing techniques using the Landsat and Seasat data independently, and then both data sets are coregistered. The images are evaluated according to the ease with which contacts can be located and rock units (not just stratigraphically adjacent ones) separated. Results show that of the Landsat images evaluated, the image using a supervised classification scheme is the best for sedimentary rock type discrimination. Of less value, in decreasing order, are color ratio composites, principal components, and the standard color composite. In addition, for rock type discrimination, the black and white Seasat image is less useful than any of the Landsat color images by itself. However, it is found that the incorporation of the surface textural measures made from the Seasat image provides a considerable and worthwhile improvement in rock type discrimination.

  14. Imaging in pulmonary hypertension, part 1: clinical perspectives, classification, imaging techniques and imaging algorithm.

    PubMed

    McCann, Caroline; Gopalan, Deepa; Sheares, Karen; Screaton, Nicholas

    2012-05-01

    Pulmonary arterial hypertension (PAH) is an uncommon condition associated with significant morbidity and mortality. It has diverse aetiology with differing clinical presentations, imaging features and treatments that range from surgical treatment of proximal chronic thromboembolic disease to targeted medical therapies in small vessel disease. Current classification of pulmonary hypertension (PH) is clinically based and groups diseases with similar pathophysiological mechanisms and therapeutic approaches. Groupings include conditions characterised by diffuse small vessel diseases such as idiopathic PAH, PH secondary to chronic hypoxic lung disease, left sided cardiac disease, chronic large vessel obstruction such as chronic thromboembolic disease and a miscellaneous group of diseases. The physiological manifestation of all of these diseases is increased pulmonary vascular resistance and PAH and while clinical features may provide a clue to diagnosis imaging plays a fundamental role in establishing a precise diagnosis and therefore guides therapy. A broad range of imaging modalities is available for the patient with suspected PH including chest radiograph, echocardiography, ventilation/perfusion scintigraphy, catheter pulmonary angiography as well as cross-sectional CT and MRI. Each modality has its strengths and limitations and different techniques may be used at different stages of diagnostic investigation and frequently complement each other. For example, while MRI and echocardiography permit cardiac structural and functional assessment, CT pulmonary angiography provides exquisite morphological information about the proximal pulmonary vasculature and lung parenchyma but little functional information. Modern cross-sectional imaging techniques (CT and MRI) hold the promise of a comprehensive evaluation of the heart, circulation and lung parenchyma in PH. The authors present a multimodality-imaging algorithm for the investigation of patients with suspected PH though

  15. Radiation-Based Medical Imaging Techniques: An Overview

    NASA Astrophysics Data System (ADS)

    Prior, John O.; Lecoq, Paul

    This chapter will present an overview of two radiation-based medical imaging techniques using radiopharmaceuticals used in nuclear medicine/molecular imaging, namely, single-photon emission computed tomography (SPECT) and positron emission tomography (PET). The relative merits in terms of radiation sensitivity and image resolution of SPECT and PET will be compared to the main conventional radiologic modalities that are computed tomography (CT) and magnetic resonance (MR) imaging. Differences in terms of temporal resolution will also be outlined, as well as the other similarities and dissimilarities of these two techniques, including their latest and upcoming multimodality combination. The main clinical applications are briefly described and examples of specific SPECT and PET radiopharmaceuticals are listed. SPECT and PET imaging will be then further detailed in the two subsequent chapters describing in greater depth the basics and future trends of each technique (see Chaps. 37, "SPECT Imaging: Basics and New Trends" 10.1007/978-3-642-13271-1_37 and 38, "PET Imaging: Basics and New Trends" 10.1007/978-3-642-13271-1_38.

  16. Video Multiple Watermarking Technique Based on Image Interlacing Using DWT

    PubMed Central

    Ibrahim, Mohamed M.; Abdel Kader, Neamat S.; Zorkany, M.

    2014-01-01

    Digital watermarking is one of the important techniques to secure digital media files in the domains of data authentication and copyright protection. In the nonblind watermarking systems, the need of the original host file in the watermark recovery operation makes an overhead over the system resources, doubles memory capacity, and doubles communications bandwidth. In this paper, a robust video multiple watermarking technique is proposed to solve this problem. This technique is based on image interlacing. In this technique, three-level discrete wavelet transform (DWT) is used as a watermark embedding/extracting domain, Arnold transform is used as a watermark encryption/decryption method, and different types of media (gray image, color image, and video) are used as watermarks. The robustness of this technique is tested by applying different types of attacks such as: geometric, noising, format-compression, and image-processing attacks. The simulation results show the effectiveness and good performance of the proposed technique in saving system resources, memory capacity, and communications bandwidth. PMID:25587570

  17. Video multiple watermarking technique based on image interlacing using DWT.

    PubMed

    Ibrahim, Mohamed M; Abdel Kader, Neamat S; Zorkany, M

    2014-01-01

    Digital watermarking is one of the important techniques to secure digital media files in the domains of data authentication and copyright protection. In the nonblind watermarking systems, the need of the original host file in the watermark recovery operation makes an overhead over the system resources, doubles memory capacity, and doubles communications bandwidth. In this paper, a robust video multiple watermarking technique is proposed to solve this problem. This technique is based on image interlacing. In this technique, three-level discrete wavelet transform (DWT) is used as a watermark embedding/extracting domain, Arnold transform is used as a watermark encryption/decryption method, and different types of media (gray image, color image, and video) are used as watermarks. The robustness of this technique is tested by applying different types of attacks such as: geometric, noising, format-compression, and image-processing attacks. The simulation results show the effectiveness and good performance of the proposed technique in saving system resources, memory capacity, and communications bandwidth.

  18. Advances in image-guided intratumoral drug delivery techniques

    PubMed Central

    Solorio, Luis; Patel, Ravi B; Wu, Hanping; Krupka, Tianyi; Exner, Agata A

    2017-01-01

    Image-guided drug delivery provides a means for treating a variety of diseases with minimal systemic involvement while concurrently monitoring treatment efficacy. These therapies are particularly useful to the field of interventional oncology, where elevation of tumor drug levels, reduction of systemic side effects and post-therapy assessment are essential. This review highlights three such image-guided procedures: transarterial chemoembolization, drug-eluting implants and convection-enhanced delivery. Advancements in medical imaging technology have resulted in a growing number of new applications, including image-guided drug delivery. This minimally invasive approach provides a comprehensive answer to many challenges with local drug delivery. Future evolution of imaging devices, image-acquisition techniques and multifunctional delivery agents will lead to a paradigm shift in patient care. PMID:22816134

  19. Image measurement technique on vibration amplitude of ultrasonic horn

    NASA Astrophysics Data System (ADS)

    Zhang, Yong-bin; Wu, Zhi-qun; Zhu, Jian-ping; He, Jian-guo; Liu, Guang-min

    2013-10-01

    The paper proposes a method to measure vibration amplitude of ultrasonic horn which is a very important component in the spindle for micro-electrical-chemical discharging machining. The method of image measuring amplitude on high frequency vibration is introduced. Non-contact measurement system based on vision technology is constructed. High precision location algorithm on image centroid, quadratic location algorithm, is presented to find the center of little light spot. Measurement experiments have been done to show the effect of image measurement technique on vibration amplitude of ultrasonic horn. In the experiments, precise calibration of the vision system is implemented using a normal graticule to obtain the scale factor between image pixel and real distance. The vibration amplitude of ultrasonic horn is changed by modifying the voltage amplitude of pulse power supply. The image of feature on ultrasonic horn is captured and image processing is carried out. The vibration amplitudes are got at different voltages.

  20. Spaceborne synthetic-aperture imaging radars - Applications, techniques, and technology

    NASA Technical Reports Server (NTRS)

    Elachi, C.; Bicknell, T.; Jordan, R. L.; Wu, C.

    1982-01-01

    In June 1978, the Seasat satellite was placed into orbit around the earth with a synthetic-aperture imaging radar (SAR) as one of the payload sensors. The Seasat SAR provided, for the first time, synoptic radar images of the earth's surface with a resolution of 25 m. In November 1981, the second imaging radar was successfully operated from space on the Shuttle. The Shuttle Imaging Radar-A acquired images over a variety of regions around the world with an imaging geometry different from the one used by the Seasat SAR. The spaceborne SAR principle is discussed, taking into account ambiguities, orbital and environmental factors, range curvature and range walk, surface interaction mechanisms, thermal and speckle noise, key tradeoff parameters, and nonconventional SAR systems. Attention is also given to spaceborne SAR sensors, the digital processing of spaceborne SAR data, the optical processing of spaceborne SAR data, postimage formation processing, data interpretation techniques and applications, and the next decade.

  1. Spinal cord injury from fluoroscopically guided intercostal blocks with phenol.

    PubMed

    Kissoon, Narayan R; Graff-Radford, Jonathan; Watson, James C; Laughin, Ruple S

    2014-01-01

    Image guided intercostal blocks are commonly performed and considered relatively safe. Chemical denervation is commonly used in clinical practice for treatment of chronic non-cancer associated pain. To report a case of spinal cord injury resulting from fluoroscopically guided intercostal blocks with phenol. Case report. Inpatient hospital service. RESULTS/CASE REPORTS: A 53 year-old women was transferred from her local facility for acute onset of lower extremity paresis beginning shortly after right intercostal nerve injections of 2 mL of preservative-free phenol at the T7, 8, 9 levels. She had previous intercostal blocks for chronic right-sided mid thoracic/abdominal pain every 3 months for at least one year without sequelae. Within 20 minutes of the injection, she developed a sensation of right leg weakness and heaviness. Over several hours she developed worsening right leg weakness, and then left leg weakness, followed by urinary retention. Admission examination revealed severe right greater than left leg weakness, right lower extremity hyperesthesia to T10, absent lower extremity reflexes, and bilateral extensor plantar responses. Magnetic resonance imaging (MRI) of the entire spine demonstrated extensive T2/DWI hyperintensity in the central spinal cord from T1 to L1 with mild cord enlargement and enhancement at T7-9 (sites of injection). Extensive serum and cerebrospinal fluid (CSF) evaluation did not show any evidence of an infectious, inflammatory, or metabolic cause to her myelopathy. Repeat MRI of the entire spine demonstrated near complete resolution of the T2 signal abnormality. One month after presentation, despite radiographic improvement, the patient showed some clinical improvement, but remained walker dependent and with neurogenic bowel and bladder. This report describes a single case report. This case offers several lessons for a pain specialist including 1) the potential for a neurologic catastrophe (spinal cord injury) from aqueous neurolytic

  2. Dose reduction in fluoroscopic interventions using a combination of a region of interest (ROI) x-ray attenuator and spatially different, temporally variable temporal filtering

    NASA Astrophysics Data System (ADS)

    Swetadri Vasan, S. N.; Pope, Liza; Ionita, Ciprian N.; Titus, A. H.; Bednarek, D. R.; Rudin, S.

    2013-03-01

    A novel dose reduction technique for fluoroscopic interventions involving a combination of a material x-ray region of interest (ROI) attenuator and spatially different, temporally variable ROI temporal recursive filter, was used to guide the catheter to the ROI in three live animal studies, two involving rabbits and one involving a sheep. In the two rabbit studies presented , a catheter was guided to the entrance of the carotid artery. With the added ROI attenuator the image under the high attenuation region is very noisy. By using temporal filtering with a filter weight of 0.6 on previous frames, the noise is reduced. In the sheep study the catheter was guided to the descending aorta of the animal. The sheep offered a relatively higher attenuation to the incident x-rays and thus a higher temporal filter weight of 0.8 on previous frames was used during the procedure to reduce the noise to levels acceptable by the interventionalist. The image sequences from both studies show that significant dose reduction of 5-6 times can be achieved with acceptable image quality outside the ROI by using the above mentioned technique. Even though the temporal filter weighting outside the ROI is higher, the consequent lag does not prevent perception of catheter movement.

  3. Dose Reduction in Fluoroscopic Interventions Using a Combination of a Region of Interest (ROI) X-Ray Attenuator and Spatially-Different, Temporally-Variable Temporal Filtering.

    PubMed

    Vasan, S N Swetadri; Pope, Liza; Ionita, Ciprian N; Titus, A H; Bednarek, D R; Rudin, S

    2013-03-06

    A novel dose reduction technique for fluoroscopic interventions involving a combination of a material x-ray region of interest (ROI) attenuator and spatially different, temporally variable ROI temporal recursive filter, was used to guide the catheter to the ROI in three live animal studies, two involving rabbits and one involving a sheep. In the two rabbit studies presented, a catheter was guided to the entrance of the carotid artery. With the added ROI attenuator the image under the high attenuation region is very noisy. By using temporal filtering with a filter weight of 0.6 on previous frames, the noise is reduced. In the sheep study the catheter was guided to the descending aorta of the animal. The sheep offered a relatively higher attenuation to the incident x-rays and thus a higher temporal filter weight of 0.8 on previous frames was used during the procedure to reduce the noise to levels acceptable by the interventionalist. The image sequences from both studies show that significant dose reduction of 5-6 times can be achieved with acceptable image quality outside the ROI by using the above mentioned technique. Even though the temporal filter weighting outside the ROI is higher, the consequent lag does not prevent perception of catheter movement.

  4. Dose Reduction in Fluoroscopic Interventions Using a Combination of a Region of Interest (ROI) X-Ray Attenuator and Spatially-Different, Temporally-Variable Temporal Filtering

    PubMed Central

    Vasan, S.N Swetadri; Pope, Liza; Ionita, Ciprian N.; Titus, A.H.; Bednarek, D.R; Rudin, S.

    2013-01-01

    A novel dose reduction technique for fluoroscopic interventions involving a combination of a material x-ray region of interest (ROI) attenuator and spatially different, temporally variable ROI temporal recursive filter, was used to guide the catheter to the ROI in three live animal studies, two involving rabbits and one involving a sheep. In the two rabbit studies presented, a catheter was guided to the entrance of the carotid artery. With the added ROI attenuator the image under the high attenuation region is very noisy. By using temporal filtering with a filter weight of 0.6 on previous frames, the noise is reduced. In the sheep study the catheter was guided to the descending aorta of the animal. The sheep offered a relatively higher attenuation to the incident x-rays and thus a higher temporal filter weight of 0.8 on previous frames was used during the procedure to reduce the noise to levels acceptable by the interventionalist. The image sequences from both studies show that significant dose reduction of 5–6 times can be achieved with acceptable image quality outside the ROI by using the above mentioned technique. Even though the temporal filter weighting outside the ROI is higher, the consequent lag does not prevent perception of catheter movement. PMID:24817800

  5. Application of optical correlation techniques to particle imaging velocimetry

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.; Edwards, Robert V.

    1988-01-01

    Pulsed laser sheet velocimetry yields nonintrusive measurements of velocity vectors across an extended 2-dimensional region of the flow field. The application of optical correlation techniques to the analysis of multiple exposure laser light sheet photographs can reduce and/or simplify the data reduction time and hardware. Here, Matched Spatial Filters (MSF) are used in a pattern recognition system. Usually MSFs are used to identify the assembly line parts. In this application, the MSFs are used to identify the iso-velocity vector contours in the flow. The patterns to be recognized are the recorded particle images in a pulsed laser light sheet photograph. Measurement of the direction of the partical image displacements between exposures yields the velocity vector. The particle image exposure sequence is designed such that the velocity vector direction is determined unambiguously. A global analysis technique is used in comparison to the more common particle tracking algorithms and Young's fringe analysis technique.

  6. Telematics techniques for image based diagnosis, therapy planning and monitoring.

    PubMed

    Bidaut, L M; Scherrer, J R

    1998-01-01

    This paper is intended to describe and illustrate some of the actual use of telematics related techniques together with modern biomedical imaging capabilities for helping in diagnosis, as well as for the planning and monitoring of therapy. To this end, most current imaging modalities are initially introduced. Then it is shown how telematics related techniques are necessary to improve the outcome of current image-based protocols. Such techniques allow data, means, or competencies--which may intrinsically be of a complementary nature or distributed at many different locations--to be integrated together and transcend the simple sum of individual expectations. Examples of actual implementations are given in the fields of radio-oncology, neurosurgery and orthopedics. To conclude, the papers and posters presented in the corresponding session of the MIE'97 symposium are summarized to provide further telematics references for the reader.

  7. Minimally Invasive Spinal Surgery with Intraoperative Image-Guided Navigation

    PubMed Central

    Kim, Terrence T.; Johnson, J. Patrick; Pashman, Robert; Drazin, Doniel

    2016-01-01

    We present our perioperative minimally invasive spine surgery technique using intraoperative computed tomography image-guided navigation for the treatment of various lumbar spine pathologies. We present an illustrative case of a patient undergoing minimally invasive percutaneous posterior spinal fusion assisted by the O-arm system with navigation. We discuss the literature and the advantages of the technique over fluoroscopic imaging methods: lower occupational radiation exposure for operative room personnel, reduced need for postoperative imaging, and decreased revision rates. Most importantly, we demonstrate that use of intraoperative cone beam CT image-guided navigation has been reported to increase accuracy. PMID:27213152

  8. Improving face image extraction by using deep learning technique

    NASA Astrophysics Data System (ADS)

    Xue, Zhiyun; Antani, Sameer; Long, L. R.; Demner-Fushman, Dina; Thoma, George R.

    2016-03-01

    The National Library of Medicine (NLM) has made a collection of over a 1.2 million research articles containing 3.2 million figure images searchable using the Open-iSM multimodal (text+image) search engine. Many images are visible light photographs, some of which are images containing faces ("face images"). Some of these face images are acquired in unconstrained settings, while others are studio photos. To extract the face regions in the images, we first applied one of the most widely-used face detectors, a pre-trained Viola-Jones detector implemented in Matlab and OpenCV. The Viola-Jones detector was trained for unconstrained face image detection, but the results for the NLM database included many false positives, which resulted in a very low precision. To improve this performance, we applied a deep learning technique, which reduced the number of false positives and as a result, the detection precision was improved significantly. (For example, the classification accuracy for identifying whether the face regions output by this Viola- Jones detector are true positives or not in a test set is about 96%.) By combining these two techniques (Viola-Jones and deep learning) we were able to increase the system precision considerably, while avoiding the need to manually construct a large training set by manual delineation of the face regions.

  9. A human visual based binarization technique for histological images

    NASA Astrophysics Data System (ADS)

    Shreyas, Kamath K. M.; Rajendran, Rahul; Panetta, Karen; Agaian, Sos

    2017-05-01

    In the field of vision-based systems for object detection and classification, thresholding is a key pre-processing step. Thresholding is a well-known technique for image segmentation. Segmentation of medical images, such as Computed Axial Tomography (CAT), Magnetic Resonance Imaging (MRI), X-Ray, Phase Contrast Microscopy, and Histological images, present problems like high variability in terms of the human anatomy and variation in modalities. Recent advances made in computer-aided diagnosis of histological images help facilitate detection and classification of diseases. Since most pathology diagnosis depends on the expertise and ability of the pathologist, there is clearly a need for an automated assessment system. Histological images are stained to a specific color to differentiate each component in the tissue. Segmentation and analysis of such images is problematic, as they present high variability in terms of color and cell clusters. This paper presents an adaptive thresholding technique that aims at segmenting cell structures from Haematoxylin and Eosin stained images. The thresholded result can further be used by pathologists to perform effective diagnosis. The effectiveness of the proposed method is analyzed by visually comparing the results to the state of art thresholding methods such as Otsu, Niblack, Sauvola, Bernsen, and Wolf. Computer simulations demonstrate the efficiency of the proposed method in segmenting critical information.

  10. A High Performance Image Data Compression Technique for Space Applications

    NASA Technical Reports Server (NTRS)

    Yeh, Pen-Shu; Venbrux, Jack

    2003-01-01

    A highly performing image data compression technique is currently being developed for space science applications under the requirement of high-speed and pushbroom scanning. The technique is also applicable to frame based imaging data. The algorithm combines a two-dimensional transform with a bitplane encoding; this results in an embedded bit string with exact desirable compression rate specified by the user. The compression scheme performs well on a suite of test images acquired from spacecraft instruments. It can also be applied to three-dimensional data cube resulting from hyper-spectral imaging instrument. Flight qualifiable hardware implementations are in development. The implementation is being designed to compress data in excess of 20 Msampledsec and support quantization from 2 to 16 bits. This paper presents the algorithm, its applications and status of development.

  11. Laser Illumination Modality of Photoacoustic Imaging Technique for Prostate Cancer

    NASA Astrophysics Data System (ADS)

    Peng, Dong-qing; Peng, Yuan-yuan; Guo, Jian; Li, Hui

    2016-02-01

    Photoacoustic imaging (PAI) has recently emerged as a promising imaging technique for prostate cancer. But there was still a lot of challenge in the PAI for prostate cancer detection, such as laser illumination modality. Knowledge of absorbed light distribution in prostate tissue was essential since the distribution characteristic of absorbed light energy would influence the imaging depth and range of PAI. In order to make a comparison of different laser illumination modality of photoacoustic imaging technique for prostate cancer, optical model of human prostate was established and combined with Monte Carlo simulation method to calculate the light absorption distribution in the prostate tissue. Characteristic of light absorption distribution of transurethral and trans-rectal illumination case, and of tumor at different location was compared with each other.The relevant conclusions would be significant for optimizing the light illumination in a PAI system for prostate cancer detection.

  12. Laparoscopic Imaging Techniques in Endometriosis Therapy: A Systematic Review.

    PubMed

    Vlek, Stijn L; Lier, M C I; Ankersmit, M; Ket, Johannes C F; Dekker, J J M L; Mijatovic, V; Tuynman, J B

    2016-01-01

    Endometriosis is a common disease associated with pelvic pain and subfertility. Laparoscopic surgical treatment has proven effective in endometriosis, but is hampered by a high rate of recurrence. The aim of this systematic review was to evaluate the intraoperative identification of endometriosis by enhanced laparoscopic imaging techniques, focusing on sensitivity and specificity. A systematic review was conducted according to PRISMA guidelines in PubMed, Embase, Cochrane Library, and Web of Science. Published prospective studies reporting on enhanced laparoscopic imaging techniques during endometriosis surgery were included. General study characteristics and reported outcomes, including sensitivity and specificity, were extracted. Nine studies were eligible for inclusion. Three techniques were described: 5-ALA fluorescence (5-ALA), autofluorescence (AFI), and narrow-band imaging (NBI). The reported sensitivity of 5-ALA and AFI for identifying endometriosis ranged from 91% to 100%, compared with 48% to 69% for conventional white light laparoscopy (WL). A randomized controlled trial comparing NBI + WL with WL alone reported better sensitivity of NBI (100% vs 79%; p < .001). All 9 studies reported an enhanced detection rate of endometriotic lesions with enhanced imaging techniques. Enhanced imaging techniques are a promising additive for laparoscopic detection and treatment of endometriosis. The 5-ALA, AFI, and NBI intraoperative imaging techniques had a better detection rate for peritoneal endometriosis compared with conventional WL laparoscopy. None of the studies reported clinical data regarding outcomes. Future studies should address long-term results, such as quality of life, recurrence, and need for reoperation. Copyright © 2016 AAGL. Published by Elsevier Inc. All rights reserved.

  13. Results on plasma temperature measurement using an image processing technique

    NASA Astrophysics Data System (ADS)

    Mahdavipour, B.; Hatami, A.; Salar Elahi, A.

    Image processing technique (IPT) is a computational technique which is a simple, wide and great for many purposes. In this paper, we used IPT to obtain plasma source such as sun and sunspot temperatures. Sun image was taken by a telescope and DSLR camera and imported to MATLAB software. Using the IPT, we cropped two areas and evaluated their RGB values, using a code which was written according to Python software. We computed wavelengths and then by substituting wavelengths in Wien's law, we obtained sun's surface and sunspot temperature's. The temperature errors for surface and sunspot were 0.57% and 13% respectively.

  14. Digital image correlation techniques applied to LANDSAT multispectral imagery

    NASA Technical Reports Server (NTRS)

    Bonrud, L. O. (Principal Investigator); Miller, W. J.

    1976-01-01

    The author has identified the following significant results. Automatic image registration and resampling techniques applied to LANDSAT data achieved accuracies, resulting in mean radial displacement errors of less than 0.2 pixel. The process method utilized recursive computational techniques and line-by-line updating on the basis of feedback error signals. Goodness of local feature matching was evaluated through the implementation of a correlation algorithm. An automatic restart allowed the system to derive control point coordinates over a portion of the image and to restart the process, utilizing this new control point information as initial estimates.

  15. Value of radionuclide imaging techniques in assessing cardiomyopathy

    SciTech Connect

    Goldman, M.R.; Boucher, C.A.

    1980-12-18

    Radionuclide imaging techniques add an important dimension to the diagnosis, classification and management of myocardial disease. The gated blood pool scan provides information allowing determination of the functional type of cardiomyopathy (congestive, restrictive or hypertrophic) as well as evaluation of ventricular performance. Myocardial perfusion imaging with thallium-201 is useful in distinguishing congestive cardiomyopathy from severe coronary artery disease and also in depicting septal abnormalities in hypertrophic cardiomyopathy. Radionuclide techniques also prove useful in following progression of disease and in evaluating the efficacy of therapeutic interventions.

  16. A novel data processing technique for image reconstruction of penumbral imaging

    NASA Astrophysics Data System (ADS)

    Xie, Hongwei; Li, Hongyun; Xu, Zeping; Song, Guzhou; Zhang, Faqiang; Zhou, Lin

    2011-06-01

    CT image reconstruction technique was applied to the data processing of the penumbral imaging. Compared with other traditional processing techniques for penumbral coded pinhole image such as Wiener, Lucy-Richardson and blind technique, this approach is brand new. In this method, the coded aperture processing method was used for the first time independent to the point spread function of the image diagnostic system. In this way, the technical obstacles was overcome in the traditional coded pinhole image processing caused by the uncertainty of point spread function of the image diagnostic system. Then based on the theoretical study, the simulation of penumbral imaging and image reconstruction was carried out to provide fairly good results. While in the visible light experiment, the point source of light was used to irradiate a 5mm×5mm object after diffuse scattering and volume scattering. The penumbral imaging was made with aperture size of ~20mm. Finally, the CT image reconstruction technique was used for image reconstruction to provide a fairly good reconstruction result.

  17. Comparative analysis of infrared images degraded by lossy compression techniques

    NASA Astrophysics Data System (ADS)

    Toussaint, W. A.; Weber, Reed A.

    2015-09-01

    This work addresses image degradation introduced by lossy compression techniques and the effects of such degradation on signal detection statistics for applications in fast-framing (<100 Hz) IR image analysis. As future space systems make use of increasingly higher pixel count IR focal plane arrays, data generation rates are anticipated to become too copious for continuous download. The prevailing solution to this issue has been to compress image data prior to downlink. While this solution is application independent for lossless compression, the expected benefits of lossy compression, including higher compression ratio, necessitate several application specific trades in order to characterize preservation of critical information within the data. Current analyses via standard statistical image processing techniques following tunably lossy compression algorithms (JPEG2000, JPEG-LS) allow for detection statistics nearly identical to analyses following standard lossless compression techniques, such as Rice and PNG, even at degradation levels offering a greater than twofold increase in compression ratio. Ongoing efforts focus on repeating the analysis for other tunably lossy compression techniques while also assessing the relative computational burden of each algorithm. Current results suggest that lossy compression techniques can preserve critical information in fast-framing IR data while either significantly reducing downlink bandwidth requirements or significantly increasing the usable focal plane array window size.

  18. A Range-Shift Technique for TOF Range Image Sensors

    NASA Astrophysics Data System (ADS)

    Sawada, Tomonari; Ito, Kana; Nakayama, Masakatsu; Kawahito, Shoji

    In Time-of-Flight (TOF) range image sensors using periodical pulsed light, there is a trade-off between the maximum range and range resolution. This paper proposes a range-shift technique for improving range resolution of the TOF range image sensor without sacrificing the measurement range. The range-shift operation uses a TOF range imaging pixel with periodical charge draining structure and several time-shifted short pulses. The use of the short pulse can improve the range resolution. The range image using the range-shift technique is synthesized with several sub-frames, each acquires one of the shifted range images. The use of the small duty-ratio pulse leads to reducing the effect of ambient light and improving the range resolution. The range-shift technique is tested with an implemented TOF range image sensor and it is found that the range resolution is improved to 2cm using a 10ns light pulse and 7 overlapped shifted ranges for the measurement range of 0.5m to 4.0m.

  19. Image Enhancement and Display Techniques Applied to SAR580 Images of Ships

    DTIC Science & Technology

    1987-04-01

    applied to the images. This report discusses tht properties of SAR ship returns, reviews the various types of image enhancement techniques applied to...Figures , , a . . . . , , , . . . , . . . . , . . iii I. INTRODUCTION . . . . . . . . . . . . I 2. PROPERTIES OF SAR SHIP IMAGES ... ... ...... I 3...Page 1 Original Ship Photos 5 2 Ship Profile and Plan Views 9 3 SAR Ship Images 14 4 SAR Contour Plots 16 5 SAR Three-Dimensional Plots 19 6 Container

  20. An improved coding technique for image encryption and key management

    NASA Astrophysics Data System (ADS)

    Wu, Xu; Ma, Jie; Hu, Jiasheng

    2005-02-01

    An improved chaotic algorithm for image encryption on the basis of conventional chaotic encryption algorithm is proposed. Two keys are presented in our technique. One is called private key, which is fixed and protected in the system. The other is named assistant key, which is public and transferred with the encrypted image together. For different original image, different assistant key should be chosen so that one could get different encrypted key. The updated encryption algorithm not only can resist a known-plaintext attack, but also offers an effective solution for key management. The analyses and the computer simulations show that the security is improved greatly, and can be easily realized with hardware.

  1. Hyperspectral imaging using the single-pixel Fourier transform technique

    NASA Astrophysics Data System (ADS)

    Jin, Senlin; Hui, Wangwei; Wang, Yunlong; Huang, Kaicheng; Shi, Qiushuai; Ying, Cuifeng; Liu, Dongqi; Ye, Qing; Zhou, Wenyuan; Tian, Jianguo

    2017-03-01

    Hyperspectral imaging technology is playing an increasingly important role in the fields of food analysis, medicine and biotechnology. To improve the speed of operation and increase the light throughput in a compact equipment structure, a Fourier transform hyperspectral imaging system based on a single-pixel technique is proposed in this study. Compared with current imaging spectrometry approaches, the proposed system has a wider spectral range (400-1100 nm), a better spectral resolution (1 nm) and requires fewer measurement data (a sample rate of 6.25%). The performance of this system was verified by its application to the non-destructive testing of potatoes.

  2. Demodulation techniques for the amplitude modulated laser imager.

    PubMed

    Mullen, Linda; Laux, Alan; Cochenour, Brandon; Zege, Eleonora P; Katsev, Iosif L; Prikhach, Alexander S

    2007-10-20

    A new technique has been found that uses in-phase and quadrature phase (I/Q) demodulation to optimize the images produced with an amplitude-modulated laser imaging system. An I/Q demodulator was used to collect the I/Q components of the received modulation envelope. It was discovered that by adjusting the local oscillator phase and the modulation frequency, the backscatter and target signals can be analyzed separately via the I/Q components. This new approach enhances image contrast beyond what was achieved with a previous design that processed only the composite magnitude information.

  3. Hyperspectral imaging using the single-pixel Fourier transform technique

    PubMed Central

    Jin, Senlin; Hui, Wangwei; Wang, Yunlong; Huang, Kaicheng; Shi, Qiushuai; Ying, Cuifeng; Liu, Dongqi; Ye, Qing; Zhou, Wenyuan; Tian, Jianguo

    2017-01-01

    Hyperspectral imaging technology is playing an increasingly important role in the fields of food analysis, medicine and biotechnology. To improve the speed of operation and increase the light throughput in a compact equipment structure, a Fourier transform hyperspectral imaging system based on a single-pixel technique is proposed in this study. Compared with current imaging spectrometry approaches, the proposed system has a wider spectral range (400–1100 nm), a better spectral resolution (1 nm) and requires fewer measurement data (a sample rate of 6.25%). The performance of this system was verified by its application to the non-destructive testing of potatoes. PMID:28338100

  4. Image analysis techniques for the study of turbulent flows

    NASA Astrophysics Data System (ADS)

    Ferrari, Simone

    In this paper, a brief review of Digital Image Analysis techniques employed in Fluid Mechanics for the study of turbulent flows is given. Particularly the focus is on the techniques developed by the research teams the Author worked in, that can be considered relatively "low cost" techniques. Digital Image Analysis techniques have the advantage, when compared to the traditional techniques employing physical point probes, to be non-intrusive and quasi-continuous in space, as every pixel on the camera sensor works as a single probe: consequently, they allow to obtain two-dimensional or three-dimensional fields of the measured quantity in less time. Traditionally, the disadvantages are related to the frequency of acquisition, but modern high-speed cameras are typically able to acquire at frequencies from the order of 1 KHz to the order of 1 MHz. Digital Image Analysis techniques can be employed to measure concentration, temperature, position, displacement, velocity, acceleration and pressure fields with similar equipment and setups, and can be consequently considered as a flexible and powerful tool for measurements on turbulent flows.

  5. Comparative analysis of NDE techniques with image processing

    NASA Astrophysics Data System (ADS)

    Rathod, Vijay R.; Anand, R. S.; Ashok, Alaknanda

    2012-12-01

    The paper reports comparative results of nondestructive testing (NDT) based experimentation done on created flaws in the casting at the Central Foundry Forge Plant (CFFP) of Bharat Heavy Electrical Ltd. India (BHEL). The present experimental study is aimed at comparing the evaluation of image processing methods applied on the radiographic images of welding defects such as slag inclusion, porosity, lack-of-root penetration and cracks with other NDT methods. Different image segmentation techniques have been proposed here for identifying the above created welding defects. Currently, there is a large amount of research work going on in the field of automated system for inspection, analysis and detection of flaws in the weldments. Comparison of other NDT methods and application of image processing on the radiographic images of weld defects are aimed to detect defects reliably and to make accept/reject decisions as per the international standard.

  6. Emerging techniques and technologies in brain tumor imaging

    PubMed Central

    Ellingson, Benjamin M.; Bendszus, Martin; Sorensen, A. Gregory; Pope, Whitney B.

    2014-01-01

    The purpose of this report is to describe the state of imaging techniques and technologies for detecting response of brain tumors to treatment in the setting of multicenter clinical trials. Within currently used technologies, implementation of standardized image acquisition and the use of volumetric estimates and subtraction maps are likely to help to improve tumor visualization, delineation, and quantification. Upon further development, refinement, and standardization, imaging technologies such as diffusion and perfusion MRI and amino acid PET may contribute to the detection of tumor response to treatment, particularly in specific treatment settings. Over the next few years, new technologies such as 23Na MRI and CEST imaging technologies will be explored for their use in expanding the ability to quantitatively image tumor response to therapies in a clinical trial setting. PMID:25313234

  7. Vegetation change detection based on image fusion technique

    NASA Astrophysics Data System (ADS)

    Jia, Yonghong; Liu, Yueyan; Yu, Hui; Li, Deren

    2005-10-01

    The change detection of land use and land cover has always been the focus of remotely sensed study and application. Based on techniques of image fusion, a new approach of detecting vegetation change according to vector of brightness index (BI) and perpendicular vegetation index (PVI) extracted from multi-temporal remotely sensed imagery is proposed. The procedure is introduced. Firstly, the Landsat eTM+ imagery is geometrically corrected and registered. Secondly, band 2,3,4 and panchromatic images of Landsat eTM+ are fused by a trous wavelet fusion, and bands 1,2,3 of SPOT are registered to the fused images. Thirdly, brightness index and perpendicular vegetation index are respectively extracted from SPOT images and fused images. Finally, change vectors are obtained and used to detect vegetation change. The testing results show that the approach of detecting vegetation change is very efficient.

  8. Modern Micro and Nanoparticle-Based Imaging Techniques

    PubMed Central

    Ryvolova, Marketa; Chomoucka, Jana; Drbohlavova, Jana; Kopel, Pavel; Babula, Petr; Hynek, David; Adam, Vojtech; Eckschlager, Tomas; Hubalek, Jaromir; Stiborova, Marie; Kaiser, Jozef; Kizek, Rene

    2012-01-01

    The requirements for early diagnostics as well as effective treatment of insidious diseases such as cancer constantly increase the pressure on development of efficient and reliable methods for targeted drug/gene delivery as well as imaging of the treatment success/failure. One of the most recent approaches covering both the drug delivery as well as the imaging aspects is benefitting from the unique properties of nanomaterials. Therefore a new field called nanomedicine is attracting continuously growing attention. Nanoparticles, including fluorescent semiconductor nanocrystals (quantum dots) and magnetic nanoparticles, have proven their excellent properties for in vivo imaging techniques in a number of modalities such as magnetic resonance and fluorescence imaging, respectively. In this article, we review the main properties and applications of nanoparticles in various in vitro imaging techniques, including microscopy and/or laser breakdown spectroscopy and in vivo methods such as magnetic resonance imaging and/or fluorescence-based imaging. Moreover the advantages of the drug delivery performed by nanocarriers such as iron oxides, gold, biodegradable polymers, dendrimers, lipid based carriers such as liposomes or micelles are also highlighted. PMID:23202187

  9. Remote sensing image denoising by using discrete multiwavelet transform techniques

    NASA Astrophysics Data System (ADS)

    Wang, Haihui; Wang, Jun; Zhang, Jian

    2006-01-01

    We present a new method by using GHM discrete multiwavelet transform in image denoising on this paper. The developments in wavelet theory have given rise to the wavelet thresholding method, for extracting a signal from noisy data. The method of signal denoising via wavelet thresholding was popularized. Multiwavelets have recently been introduced and they offer simultaneous orthogonality, symmetry and short support. This property makes multiwavelets more suitable for various image processing applications, especially denoising. It is based on thresholding of multiwavelet coefficients arising from the standard scalar orthogonal wavelet transform. It takes into account the covariance structure of the transform. Denoising of images via thresholding of the multiwavelet coefficients result from preprocessing and the discrete multiwavelet transform can be carried out by treating the output in this paper. The form of the threshold is carefully formulated and is the key to the excellent results obtained in the extensive numerical simulations of image denoising. We apply the multiwavelet-based to remote sensing image denoising. Multiwavelet transform technique is rather a new method, and it has a big advantage over the other techniques that it less distorts spectral characteristics of the image denoising. The experimental results show that multiwavelet based image denoising schemes outperform wavelet based method both subjectively and objectively.

  10. Microvascular imaging: techniques and opportunities for clinical physiological measurements.

    PubMed

    Allen, John; Howell, Kevin

    2014-07-01

    The microvasculature presents a particular challenge in physiological measurement because the vessel structure is spatially inhomogeneous and perfusion can exhibit high variability over time. This review describes, with a clinical focus, the wide variety of methods now available for imaging of the microvasculature and their key applications. Laser Doppler perfusion imaging and laser speckle contrast imaging are established, commercially-available techniques for determining microvascular perfusion, with proven clinical utility for applications such as burn-depth assessment. Nailfold capillaroscopy is also commercially available, with significant published literature that supports its use for detecting microangiopathy secondary to specific connective tissue diseases in patients with Raynaud's phenomenon. Infrared thermography measures skin temperature and not perfusion directly, and it has only gained acceptance for some surgical and peripheral microvascular applications. Other emerging technologies including imaging photoplethysmography, optical coherence tomography, photoacoustic tomography, hyperspectral imaging, and tissue viability imaging are also described to show their potential as techniques that could become established tools for clinical microvascular assessment. Growing interest in the microcirculation has helped drive the rapid development in perfusion imaging of the microvessels, bringing exciting opportunities in microvascular research.

  11. Magneto-optical imaging technique for hostile environments: The ghost imaging approach

    SciTech Connect

    Meda, A.; Caprile, A.; Avella, A.; Ruo Berchera, I.; Degiovanni, I. P.; Magni, A.; Genovese, M.

    2015-06-29

    In this paper, we develop an approach to magneto optical imaging (MOI), applying a ghost imaging (GI) protocol to perform Faraday microscopy. MOI is of the utmost importance for the investigation of magnetic properties of material samples, through Weiss domains shape, dimension and dynamics analysis. Nevertheless, in some extreme conditions such as cryogenic temperatures or high magnetic field applications, there exists a lack of domain images due to the difficulty in creating an efficient imaging system in such environments. Here, we present an innovative MOI technique that separates the imaging optical path from the one illuminating the object. The technique is based on thermal light GI and exploits correlations between light beams to retrieve the image of magnetic domains. As a proof of principle, the proposed technique is applied to the Faraday magneto-optical observation of the remanence domain structure of an yttrium iron garnet sample.

  12. Magneto-optical imaging technique for hostile environments: The ghost imaging approach

    NASA Astrophysics Data System (ADS)

    Meda, A.; Caprile, A.; Avella, A.; Ruo Berchera, I.; Degiovanni, I. P.; Magni, A.; Genovese, M.

    2015-06-01

    In this paper, we develop an approach to magneto optical imaging (MOI), applying a ghost imaging (GI) protocol to perform Faraday microscopy. MOI is of the utmost importance for the investigation of magnetic properties of material samples, through Weiss domains shape, dimension and dynamics analysis. Nevertheless, in some extreme conditions such as cryogenic temperatures or high magnetic field applications, there exists a lack of domain images due to the difficulty in creating an efficient imaging system in such environments. Here, we present an innovative MOI technique that separates the imaging optical path from the one illuminating the object. The technique is based on thermal light GI and exploits correlations between light beams to retrieve the image of magnetic domains. As a proof of principle, the proposed technique is applied to the Faraday magneto-optical observation of the remanence domain structure of an yttrium iron garnet sample.

  13. Study pollen grains in rice by using multispectral imaging techniques

    NASA Astrophysics Data System (ADS)

    Wu, Qiongshui; Hu, Yaojun; Ke, Hengyu; Zeng, Libo; Ding, Yi

    2005-03-01

    This paper describes a novel multispectral imaging microscope and its applications in the study of pollen grains in rice. The Imaging instruments can simultaneously record both spectral and spatial information of a sample, which is helpful to study the chemical states and physical properties of the sample by taking advantage of spatial image processing and spectroscopic analysis techniques. A LCTF (liquid crystal tunable filter) device is used for fast wavelength selection in the range of 400nm to 720nm and a cooled two-dimensional monochrome CCD for image detection. In this paper, the image acquisition process, spatial and spectral calibration and spectral imaging analysis methods are detailed. And also a novel method using this multispectral imaging microscope to observe rice pollen grains is reported here. The multispectral images were systematically processed and analyzed by the software. The results illustrated that the transmittance analysis of multispectral pollen images can accurately identify the pollen abortion stage of male-sterile rice, and can easily distinguish a variety of male sterile cytoplasm. Compared with cytological and histochemical methods reported previously, the method reported here has demonstrated to be more efficient and reliable in the study of chemical states and physical properties in plant cells.

  14. Microscopic Image Photography Techniques of the Past, Present, and Future.

    PubMed

    Morrison, Annie O; Gardner, Jerad M

    2015-12-01

    The field of pathology is driven by microscopic images. Educational activities for trainees and practicing pathologists alike are conducted through exposure to images of a variety of pathologic entities in textbooks, publications, online tutorials, national and international conferences, and interdepartmental conferences. During the past century and a half, photographic technology has progressed from primitive and bulky, glass-lantern projector slides to static and/or whole slide digital-image formats that can now be transferred around the world in a matter of moments via the Internet. To provide a historic and technologic overview of the evolution of microscopic-image photographic tools and techniques. Primary historic methods of microscopic image capture were delineated through interviews conducted with senior staff members in the Emory University Department of Pathology. Searches for the historic image-capturing methods were conducted using the Google search engine. Google Scholar and PubMed databases were used to research methods of digital photography, whole slide scanning, and smart phone cameras for microscopic image capture in a pathology practice setting. Although film-based cameras dominated for much of the time, the rise of digital cameras outside of pathology generated a shift toward digital-image capturing methods, including mounted digital cameras and whole slide digital-slide scanning. Digital image capture techniques have ushered in new applications for slide sharing and second-opinion consultations of unusual or difficult cases in pathology. With their recent surge in popularity, we suspect that smart phone cameras are poised to become a widespread, cost-effective method for pathology image acquisition.

  15. X-ray beam modulation, image acquisition and real-time processing in region-of-interest fluoroscopy

    NASA Astrophysics Data System (ADS)

    Yang, Chang-Ying Joseph

    2000-07-01

    Region of interest (ROI) fluoroscopy is a technique whereby a partially attenuating filter with an aperture in the center is placed in the x-ray beam between the source and the patient The part of the x-ray beam going through the filter aperture un-attenuated is used to project the main features of interest in the patient to form the ROI in each fluoroscopic image. The periphery of the image is formed by the projection of the features needed only for reference using the part of the attenuated x-ray beam passing through the filter. This technique can substantially reduce patient and staff dose and improve the image quality in the ROI of the image. By using Gd for the filter material, it is even possible to improve the x-ray attenuation contrast in the periphery. However, real-time image processing is needed to compensate for the x-ray intensity attenuation in the periphery so that the brightness in the two parts of the fluoroscopic image is linearity is restored. Based on the method of binary masks, a system was developed to perform the real-time image processing with the flexibility to accommodate both the horizontal and vertical movement of the imaging chain relative to the patient. A binary mask is a binary image used to define those regions in the fluoroscopic image which should be processed and those which should not. A method of binary mask generation was proposed so the region defined as not to be processed in the binary mask maintains as close a resemblance as possible to the ROI of the fluoroscopic image. The construction method for the look-up table used for the processing of the periphery and its dependence on physical quantities were described and studied. An algorithm for constantly tracking the change of the ROI in the fluoroscopic images and selecting the proper corresponding binary mask was developed. The quality of the processed ROI fluoroscopic images such as brightness, contrast and noise were evaluated and compared using test phantoms. The test

  16. Analysis of soil images applying Laplacian Pyramidal techniques

    NASA Astrophysics Data System (ADS)

    Ballesteros, F.; de Castro, J.; Tarquis, A. M.; Méndez, A.

    2012-04-01

    The Laplacian pyramid is a technique for image encoding in which local operators of many scales but identical shape are the basis functions. Our work describes some properties of the filters of the Laplacian pyramid. Specially, we pay attention to Gaussian and fractal behaviour of these filters, and we determine the normal and fractal ranges in the case of single parameter filters, while studying the influence of these filters in soil image processing. One usual property of any image is that neighboring pixels are highly correlated. This property makes inefficient to represent the image directly in terms of the pixel values, because most of the encoded information would be redundant. Burt and Adelson designed a technique, named Laplacian pyramid, for removing image correlation which combines features of predictive and transform methods. This technique is non causal, and its computations are simple and local. The predicted value for each pixel is computed as a local weighted average, using a unimodal weighting function centred on the pixel itself. Pyramid construction is equivalent to convolving the original image with a set of weighting functions determined by a parameter that defines the filter. According to the parameter values, these filters have a behaviour that goes from the Gaussian shape to the fractal. Previous works only analyze Gaussian filters, but we determine the Gaussian and fractal intervals and study the energy of the Laplacian pyramid images according to the filter types. The different behaviour, qualitatively, involves a significant change in statistical characteristics at different levels of iteration, especially the fractal case, which can highlight specific information from the images. Funding provided by Spanish Ministerio de Ciencia e Innovación (MICINN) through project no. AGL2010-21501/AGR is greatly appreciated.

  17. Patient radiation dose audits for fluoroscopically guided interventional procedures

    SciTech Connect

    Balter, Stephen; Rosenstein, Marvin; Miller, Donald L.; Schueler, Beth; Spelic, David

    2011-03-15

    Purpose: Quality management for any use of medical x-ray imaging should include monitoring of radiation dose. Fluoroscopically guided interventional (FGI) procedures are inherently clinically variable and have the potential for inducing deterministic injuries in patients. The use of a conventional diagnostic reference level is not appropriate for FGI procedures. A similar but more detailed quality process for management of radiation dose in FGI procedures is described. Methods: A method that takes into account both the inherent variability of FGI procedures and the risk of deterministic injuries from these procedures is suggested. The substantial radiation dose level (SRDL) is an absolute action level (with regard to patient follow-up) below which skin injury is highly unlikely and above which skin injury is possible. The quality process for FGI procedures collects data from all instances of a given procedure from a number of facilities into an advisory data set (ADS). An individual facility collects a facility data set (FDS) comprised of all instances of the same procedure at that facility. The individual FDS is then compared to the multifacility ADS with regard to the overall shape of the dose distributions and the percent of instances in both the ADS and the FDS that exceed the SRDL. Results: Samples of an ADS and FDS for percutaneous coronary intervention, using the dose metric of reference air kerma (K{sub a,r}) (i.e., the cumulative air kerma at the reference point), are used to illustrate the proposed quality process for FGI procedures. Investigation is warranted whenever the FDS is noticeably different from the ADS for the specific FGI procedure and particularly in two circumstances: (1) When the facility's local median K{sub a,r} exceeds the 75th percentile of the ADS and (2) when the percent of instances where K{sub a,r} exceeds the facility-selected SRDL is greater for the FDS than for the ADS. Conclusions: Analysis of the two data sets (ADS and FDS) and

  18. Image analysis techniques associated with automatic data base generation.

    NASA Technical Reports Server (NTRS)

    Bond, A. D.; Ramapriyan, H. K.; Atkinson, R. J.; Hodges, B. C.; Thomas, D. T.

    1973-01-01

    This paper considers some basic problems relating to automatic data base generation from imagery, the primary emphasis being on fast and efficient automatic extraction of relevant pictorial information. Among the techniques discussed are recursive implementations of some particular types of filters which are much faster than FFT implementations, a 'sequential similarity detection' technique of implementing matched filters, and sequential linear classification of multispectral imagery. Several applications of the above techniques are presented including enhancement of underwater, aerial and radiographic imagery, detection and reconstruction of particular types of features in images, automatic picture registration and classification of multiband aerial photographs to generate thematic land use maps.

  19. Ulcerated Radiodermatitis Induced after Fluoroscopically Guided Stent Implantation Angioplasty

    PubMed Central

    Herz-Ruelas, Maira Elizabeth; Gómez-Flores, Minerva; Moxica-del Angel, Joaquín; Miranda-Maldonado, Ivett; Gutiérrez-Villarreal, Ilse Marilú; Villarreal-Rodríguez, Adriana Orelia

    2014-01-01

    Cases of radiation-induced skin injury after fluoroscopically guided procedures have been reported since 1996, though the majority of them have been published in Radiology and Cardiology literature, less frequently in Dermatology journals. Chronic radiation dermatitis induced by fluoroscopy can be difficult to diagnose; a high grade of suspicion is required. We report a case of an obese 46-year-old man with hypertension, dyslipidemia, and severe coronary artery disease. He developed a pruritic and painful atrophic ulcerated skin plaque over his left scapula, six months after fluoroscopically guided stent implantation angioplasty. The diagnosis of radiodermatitis was confirmed histologically. We report this case to emphasize the importance of recognizing fluoroscopy as a cause of radiation dermatitis. A good clinical follow-up at regular intervals is important after long and complicated procedures, since the most prevalent factor for injury is long exposure time. PMID:25276441

  20. Measurement of hyoid and laryngeal displacement in video fluoroscopic swallowing studies: variability, reliability, and measurement error.

    PubMed

    Sia, Isaac; Carvajal, Pamela; Carnaby-Mann, Giselle D; Crary, Michael A

    2012-06-01

    Video fluoroscopy is commonly used in the study of swallowing kinematics. However, various procedures used in linear measurements obtained from video fluoroscopy may contribute to increased variability or measurement error. This study evaluated the influence of calibration referent and image rotation on measurement variability for hyoid and laryngeal displacement during swallowing. Inter- and intrarater reliabilities were also estimated for hyoid and laryngeal displacement measurements across conditions. The use of different calibration referents did not contribute significantly to variability in measures of hyoid and laryngeal displacement but image rotation affected horizontal measures for both structures. Inter- and intrarater reliabilities were high. Using the 95% confidence interval as the error index, measurement error was estimated to range from 2.48 to 3.06 mm. These results address procedural decisions for measuring hyoid and laryngeal displacement in video fluoroscopic swallowing studies.

  1. Comparing Imaging and Non-Imaging Techniques for Reducing Background Clutter and Resolving Distant Point Sources

    SciTech Connect

    Wurtz, R; Ziock, K; Fabris, L; Graham, R

    2005-11-10

    To reach maximum sensitivity, any method used to search for orphan sources must be insensitive to local variations of the background. Using imaging and non-imaging techniques, we analyzed the same data acquired by a search instrument deployed as a large-area, coded-mask imager. Data from many passes past a 1 mCi source at 65 m from the instrument were used to construct a model of the instrument response. We then used the model to ''hide'' the source in data taken in a light urban environment. We compared the success of detecting the hidden sources using imaging coded-mask methods, pseudo-imaging based on a zero-area matched filter, and non-imaging using simple thresholding. The results clearly indicate the superiority of imaging with the coded-mask techniques returning the best results.

  2. Feminist Pedagogy, Body Image, and the Dance Technique Class

    ERIC Educational Resources Information Center

    Barr, Sherrie; Oliver, Wendy

    2016-01-01

    This paper investigates the evolution of feminist consciousness in dance technique class as related to body image, the myth of the perfect body, and the development of feminist pedagogy. Western concert dance forms have often been taught in a manner where imitating the teacher is primary in the learning process. In this traditional scenario,…

  3. Feminist Pedagogy, Body Image, and the Dance Technique Class

    ERIC Educational Resources Information Center

    Barr, Sherrie; Oliver, Wendy

    2016-01-01

    This paper investigates the evolution of feminist consciousness in dance technique class as related to body image, the myth of the perfect body, and the development of feminist pedagogy. Western concert dance forms have often been taught in a manner where imitating the teacher is primary in the learning process. In this traditional scenario,…

  4. Recent Advances in Techniques for Hyperspectral Image Processing

    NASA Technical Reports Server (NTRS)

    Plaza, Antonio; Benediktsson, Jon Atli; Boardman, Joseph W.; Brazile, Jason; Bruzzone, Lorenzo; Camps-Valls, Gustavo; Chanussot, Jocelyn; Fauvel, Mathieu; Gamba, Paolo; Gualtieri, Anthony; Marconcini, Mattia; Tilton, James C.; Trianni, Giovanna

    2009-01-01

    Imaging spectroscopy, also known as hyperspectral imaging, has been transformed in less than 30 years from being a sparse research tool into a commodity product available to a broad user community. Currently, there is a need for standardized data processing techniques able to take into account the special properties of hyperspectral data. In this paper, we provide a seminal view on recent advances in techniques for hyperspectral image processing. Our main focus is on the design of techniques able to deal with the highdimensional nature of the data, and to integrate the spatial and spectral information. Performance of the discussed techniques is evaluated in different analysis scenarios. To satisfy time-critical constraints in specific applications, we also develop efficient parallel implementations of some of the discussed algorithms. Combined, these parts provide an excellent snapshot of the state-of-the-art in those areas, and offer a thoughtful perspective on future potentials and emerging challenges in the design of robust hyperspectral imaging algorithms

  5. Image analysis techniques for automated IVUS contour detection.

    PubMed

    Papadogiorgaki, Maria; Mezaris, Vasileios; Chatzizisis, Yiannis S; Giannoglou, George D; Kompatsiaris, Ioannis

    2008-09-01

    Intravascular ultrasound (IVUS) constitutes a valuable technique for the diagnosis of coronary atherosclerosis. The detection of lumen and media-adventitia borders in IVUS images represents a necessary step towards the reliable quantitative assessment of atherosclerosis. In this work, a fully automated technique for the detection of lumen and media-adventitia borders in IVUS images is presented. This comprises two different steps for contour initialization: one for each corresponding contour of interest and a procedure for the refinement of the detected contours. Intensity information, as well as the result of texture analysis, generated by means of a multilevel discrete wavelet frames decomposition, are used in two different techniques for contour initialization. For subsequently producing smooth contours, three techniques based on low-pass filtering and radial basis functions are introduced. The different combinations of the proposed methods are experimentally evaluated in large datasets of IVUS images derived from human coronary arteries. It is demonstrated that our proposed segmentation approaches can quickly and reliably perform automated segmentation of IVUS images.

  6. Evaluation of optical reflectance techniques for imaging of alveolar structure

    NASA Astrophysics Data System (ADS)

    Unglert, Carolin I.; Namati, Eman; Warger, William C.; Liu, Linbo; Yoo, Hongki; Kang, DongKyun; Bouma, Brett E.; Tearney, Guillermo J.

    2012-07-01

    Three-dimensional (3-D) visualization of the fine structures within the lung parenchyma could advance our understanding of alveolar physiology and pathophysiology. Current knowledge has been primarily based on histology, but it is a destructive two-dimensional (2-D) technique that is limited by tissue processing artifacts. Micro-CT provides high-resolution three-dimensional (3-D) imaging within a limited sample size, but is not applicable to intact lungs from larger animals or humans. Optical reflectance techniques offer the promise to visualize alveolar regions of the large animal or human lung with sub-cellular resolution in three dimensions. Here, we present the capabilities of three optical reflectance techniques, namely optical frequency domain imaging, spectrally encoded confocal microscopy, and full field optical coherence microscopy, to visualize both gross architecture as well as cellular detail in fixed, phosphate buffered saline-immersed rat lung tissue. Images from all techniques were correlated to each other and then to corresponding histology. Spatial and temporal resolution, imaging depth, and suitability for in vivo probe development were compared to highlight the merits and limitations of each technology for studying respiratory physiology at the alveolar level.

  7. Recent Advances in Techniques for Hyperspectral Image Processing

    NASA Technical Reports Server (NTRS)

    Plaza, Antonio; Benediktsson, Jon Atli; Boardman, Joseph W.; Brazile, Jason; Bruzzone, Lorenzo; Camps-Valls, Gustavo; Chanussot, Jocelyn; Fauvel, Mathieu; Gamba, Paolo; Gualtieri, Anthony; hide

    2009-01-01

    Imaging spectroscopy, also known as hyperspectral imaging, has been transformed in less than 30 years from being a sparse research tool into a commodity product available to a broad user community. Currently, there is a need for standardized data processing techniques able to take into account the special properties of hyperspectral data. In this paper, we provide a seminal view on recent advances in techniques for hyperspectral image processing. Our main focus is on the design of techniques able to deal with the highdimensional nature of the data, and to integrate the spatial and spectral information. Performance of the discussed techniques is evaluated in different analysis scenarios. To satisfy time-critical constraints in specific applications, we also develop efficient parallel implementations of some of the discussed algorithms. Combined, these parts provide an excellent snapshot of the state-of-the-art in those areas, and offer a thoughtful perspective on future potentials and emerging challenges in the design of robust hyperspectral imaging algorithms

  8. Statistical Techniques for Efficient Indexing and Retrieval of Document Images

    ERIC Educational Resources Information Center

    Bhardwaj, Anurag

    2010-01-01

    We have developed statistical techniques to improve the performance of document image search systems where the intermediate step of OCR based transcription is not used. Previous research in this area has largely focused on challenges pertaining to generation of small lexicons for processing handwritten documents and enhancement of poor quality…

  9. Techniques for Field Application of Lingual Ultrasound Imaging

    ERIC Educational Resources Information Center

    Gick, Bryan; Bird, Sonya; Wilson, Ian

    2005-01-01

    Techniques are discussed for using ultrasound for lingual imaging in field-related applications. The greatest challenges we have faced distinguishing the field setting from the laboratory setting are the lack of controlled head/transducer movement, and the related issue of tissue compression. Two experiments are reported. First, a pilot study…

  10. A Narrow Band Imaging Technique for Passive Radar (Preprint)

    DTIC Science & Technology

    2014-10-09

    valuable role in narrowband imaging in concert with the Doppler technique as well as more conventional approaches [1]. Passive Bistatic Radar (PBR...targets at ranges of 2 and 2.5 m. A stationary X- band horn antenna with a 50°, 3 dB beamwidth was placed approximately 2.25 m from a linear target

  11. Techniques for Field Application of Lingual Ultrasound Imaging

    ERIC Educational Resources Information Center

    Gick, Bryan; Bird, Sonya; Wilson, Ian

    2005-01-01

    Techniques are discussed for using ultrasound for lingual imaging in field-related applications. The greatest challenges we have faced distinguishing the field setting from the laboratory setting are the lack of controlled head/transducer movement, and the related issue of tissue compression. Two experiments are reported. First, a pilot study…

  12. Image encryption techniques based on the fractional Fourier transform

    NASA Astrophysics Data System (ADS)

    Hennelly, B. M.; Sheridan, J. T.

    2003-11-01

    The fractional Fourier transform, (FRT), is a generalisation of the Fourier transform which allows domains of mixed spatial frequency and spatial information to be examined. A number of method have recently been proposed in the literature for the encryption of two dimensional information using optical systems based on the FRT. Typically, these methods require random phase screen keys to decrypt the data, which must be stored at the receiver and must be carefully aligned with the received encrypted data. We have proposed a new technique based on a random shifting or Jigsaw transformation. This method does not require the use of phase keys. The image is encrypted by juxtaposition of sections of the image in various FRT domains. The new method has been compared numerically with existing methods and shows comparable or superior robustness to blind decryption. An optical implementation is also proposed and the sensitivity of the various encryption keys to blind decryption is quantified. We also present a second image encryption technique, which is based on a recently proposed method of optical phase retrieval using the optical FRT and one of its discrete counterparts. Numerical simulations of the new algorithm indicates that the sensitivity of the keys is much greater than any of the techniques currently available. In fact the sensitivity appears to be so high that optical implementation, based on existing optical signal processing technology, may be impossible. However, the technique has been shown to be a powerful method of 2-D image data encryption.

  13. Statistical Techniques for Efficient Indexing and Retrieval of Document Images

    ERIC Educational Resources Information Center

    Bhardwaj, Anurag

    2010-01-01

    We have developed statistical techniques to improve the performance of document image search systems where the intermediate step of OCR based transcription is not used. Previous research in this area has largely focused on challenges pertaining to generation of small lexicons for processing handwritten documents and enhancement of poor quality…

  14. Characterization of burns using hyperspectral imaging technique - a preliminary study.

    PubMed

    Calin, Mihaela Antonina; Parasca, Sorin Viorel; Savastru, Roxana; Manea, Dragos

    2015-02-01

    Surgical burn treatment depends on accurate estimation of burn depth. Many methods have been used to asses burns, but none has gained wide acceptance. Hyperspectral imaging technique has recently entered the medical research field with encouraging results. In this paper we present a preliminary study (case presentation) that aims to point out the value of this optical method in burn wound characterization and to set up future lines of investigation. A hyperspectral image of a leg and foot with partial thickness burns was obtained in the fifth postburn day. The image was analyzed using linear spectral unmixing model as a tool for mapping the investigated areas. The article gives details on the mathematical bases of the interpretation model and correlations with clinical examination pointing out the advantages of hyperspectral imaging technique. While the results were encouraging, further more extended and better founded studies are being prepared before recognizing hyperspectral imaging technique as an applicable method of burn wound assessment. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

  15. Imaging of contact acoustic nonlinearity using synthetic aperture technique.

    PubMed

    Yun, Dongseok; Kim, Jongbeom; Jhang, Kyung-Young

    2013-09-01

    The angle beam incidence and reflection technique for the evaluation of contact acoustic nonlinearity (CAN) at solid-solid contact interfaces (e.g., closed cracks) has recently been developed to overcome the disadvantage of accessing both the inner and outer surfaces of structures for attaching pulsing and receiving transducers in the through-transmission of normal incidence technique. This paper proposes a technique for B-mode imaging of CAN based on the above reflection technique, which uses the synthetic aperture focusing technique (SAFT) and short-time Fourier transform (STFT) to visualize the distribution of the CAN-induced second harmonic magnitude as well as the nonlinear parameter. In order to verify the usefulness of the proposed method, a solid-solid contact interface was tested and the change of the contact acoustic nonlinearity according to the increasing contact pressure was visualized in images of the second harmonic magnitude and the relative nonlinear parameter. The experimental results showed good agreement with the previously developed theory identifying the dependence of the scattered second harmonics on the contact pressure. This technique can be used for the detection and improvement of the sizing accuracy of closed cracks that are difficult to detect using the conventional linear ultrasonic technique.

  16. Comparison of mouse mammary gland imaging techniques and applications: Reflectance confocal microscopy, GFP Imaging, and ultrasound

    PubMed Central

    Tilli, Maddalena T; Parrish, Angela R; Cotarla, Ion; Jones, Laundette P; Johnson, Michael D; Furth, Priscilla A

    2008-01-01

    Background Genetically engineered mouse models of mammary gland cancer enable the in vivo study of molecular mechanisms and signaling during development and cancer pathophysiology. However, traditional whole mount and histological imaging modalities are only applicable to non-viable tissue. Methods We evaluated three techniques that can be quickly applied to living tissue for imaging normal and cancerous mammary gland: reflectance confocal microscopy, green fluorescent protein imaging, and ultrasound imaging. Results In the current study, reflectance confocal imaging offered the highest resolution and was used to optically section mammary ductal structures in the whole mammary gland. Glands remained viable in mammary gland whole organ culture when 1% acetic acid was used as a contrast agent. Our application of using green fluorescent protein expressing transgenic mice in our study allowed for whole mammary gland ductal structures imaging and enabled straightforward serial imaging of mammary gland ducts in whole organ culture to visualize the growth and differentiation process. Ultrasound imaging showed the lowest resolution. However, ultrasound was able to detect mammary preneoplastic lesions 0.2 mm in size and was used to follow cancer growth with serial imaging in living mice. Conclusion In conclusion, each technique enabled serial imaging of living mammary tissue and visualization of growth and development, quickly and with minimal tissue preparation. The use of the higher resolution reflectance confocal and green fluorescent protein imaging techniques and lower resolution ultrasound were complementary. PMID:18215290

  17. The Application of Special Computing Techniques to Speed-Up Image Feature Extraction and Processing Techniques.

    DTIC Science & Technology

    1981-12-01

    of image feature extrac - tion and processing techniques. 1.2 Project Objectives The objective of this project is to demonstrate the increased...computer architecture over a conventional or serial machine in terms of image feature extrac - 53 tion and processing. Thus, essentially one can simply...and Cybernetics, vol. SMC-7, no. 3, March, 1977. 23. K.S. Shanmugam, F.M. Dickey, and J.A. Green , "A Optimal Prequency Domain Filter for Edge Detection

  18. Adaptive differential correspondence imaging based on sorting technique

    NASA Astrophysics Data System (ADS)

    Wu, Heng; Zhang, Xianmin; Shan, Yilin; He, Zhenya; Li, Hai; Luo, Chunling

    2017-04-01

    We develop an adaptive differential correspondence imaging (CI) method using a sorting technique. Different from the conventional CI schemes, the bucket detector signals (BDS) are first processed by a differential technique, and then sorted in a descending (or ascending) order. Subsequently, according to the front and last several frames of the sorted BDS, the positive and negative subsets (PNS) are created by selecting the relative frames from the reference detector signals. Finally, the object image is recovered from the PNS. Besides, an adaptive method based on two-step iteration is designed to select the optimum number of frames. To verify the proposed method, a single-detector computational ghost imaging (GI) setup is constructed. We experimentally and numerically compare the performance of the proposed method with different GI algorithms. The results show that our method can improve the reconstruction quality and reduce the computation cost by using fewer measurement data.

  19. Novel technique in the segmentation of magnetic resonance image

    NASA Astrophysics Data System (ADS)

    Chan, Kwok-Leung

    1996-04-01

    In this investigation, automatic image segmentation is carried out on magnetic resonance image (MRI). A novel technique based on the maximum minimum measure is devised. The measure is improved by combining the smoothing and counting processes, and then normalizing the number of maximum and minimum positions over the region of interest (ROI). Two parameters (MM_H and MM_V) are generated and used for the segmentation. The technique is tested on some brain MRIs of a human male from the Visible Human Project of the National Library of Medicine, National Institutes of Health, USA. Preliminary results indicate that the maximum minimum measure can provide effective parameters for human tissue characterization and image segmentation with an added advantage of faster computation.

  20. Implementation of Image-Guidance Techniques in Radiation Therapy

    NASA Astrophysics Data System (ADS)

    Thomas, Michael; Clark, Brenda; MacPherson, Miller; Montgomery, Lynn; Gerig, Lee

    2008-06-01

    For more than 100 years, physicists have been a vital part of the medical team required to deliver radiation therapy. Their role encompasses the verification of dose accuracy to the development and implementation of new techniques, the most recent of which is the incorporation of daily image guidance to account for inter- and intra-fraction target changes. For example, computed tomography (CT) integrated into radiotherapy treatment units allows the image-guided treatment of the prostate where the target location depends on the degree of rectal filling--a parameter that changes on timescales from minutes to weeks. Different technology is required for the adequate treatment of small lung tumours since respiration occurs on timescales of seconds. This presentation will review current image-guided techniques.

  1. Clutter removal techniques for GPR images in structure inspection tasks

    NASA Astrophysics Data System (ADS)

    Vuksanovic, Branislav; Bostanudin, Nurul Jihan Farhah

    2012-04-01

    This document analyses the performance of subspace signal processing techniques applied to ground penetrating radar (GPR) images in order to reduce the amount of clutter and noise in the measured GPR image. Two methods considered in this work are Principal Component Analysis (PCA) and Independent Component Analysis (ICA). An approach to combine those two techniques to improve their effectiveness when applied to GPR data is proposed in this paper. The experiments performed to gather GPR data and evaluate proposed algorithms are also described. The aim of undertaken experiments is to replicate conditions found in water reservoirs where cracks and holes in the reservoir foundations and joints cause excessive water leakages and losses to water companies and the UK economy in general. Performance of implemented algorithms is discussed and compared to the results achieved by a highly skilled human - GPR image analyst.

  2. Medical Image Processing Using Real-Time Optical Fourier Technique

    NASA Astrophysics Data System (ADS)

    Rao, D. V. G. L. N.; Panchangam, Appaji; Sastry, K. V. L. N.; Material Science Team

    2001-03-01

    Optical Image Processing Techniques are inherently fast in view of parallel processing. A self-adaptive Optical Fourier Processing system using photo induced dichroism in a Bacteriorhodopsin film was experimentally demonstrated for medical image processing. Application of this powerful analog all-optical interactive technique for cancer diagnostics is illustrated with mammograms and Pap smears. Micro calcification clusters buried in surrounding tissue showed up clearly in the processed image. By playing with one knob, which rotates the analyzer in the optical system, either the micro calcification clusters or the surrounding dense tissue can be selectively displayed. Bacteriorhodopsin films are stable up to 140^oC and environmental friendly. As no interference is involved in the experiments, vibration isolation and even a coherent light source are not required. It may be possible to develop a low-cost rugged battery operated portable signal-enhancing magnifier.

  3. Novel imaging techniques as response biomarkers in cervical cancer.

    PubMed

    Harry, Vanessa N

    2010-02-01

    The use of novel imaging techniques that have the ability to evaluate tumour biology and function shows a great deal of promise in providing early surrogate biomarkers of response to therapy which may allow for individualised or patient-specific regimes. This would have considerable clinical benefit in allowing for a treatment regimen tailored accordingly to meet the expected response, thereby reducing morbidity. Several of these imaging modalities such as dynamic contrast-enhanced MRI (DCE-MRI), diffusion-weighted MRI (DW-MRI), MR spectroscopy (MRS) and fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) are now being introduced into the field of gynaecological oncology, with the majority of work being performed on cervical tumours. This review examines the use of these functional imaging techniques as response biomarkers in cervical cancer. Copyright 2009 Elsevier Inc. All rights reserved.

  4. Imaging and machine learning techniques for diagnosis of Alzheimer's disease.

    PubMed

    Mirzaei, Golrokh; Adeli, Anahita; Adeli, Hojjat

    2016-12-01

    Alzheimer's disease (AD) is a common health problem in elderly people. There has been considerable research toward the diagnosis and early detection of this disease in the past decade. The sensitivity of biomarkers and the accuracy of the detection techniques have been defined to be the key to an accurate diagnosis. This paper presents a state-of-the-art review of the research performed on the diagnosis of AD based on imaging and machine learning techniques. Different segmentation and machine learning techniques used for the diagnosis of AD are reviewed including thresholding, supervised and unsupervised learning, probabilistic techniques, Atlas-based approaches, and fusion of different image modalities. More recent and powerful classification techniques such as the enhanced probabilistic neural network of Ahmadlou and Adeli should be investigated with the goal of improving the diagnosis accuracy. A combination of different image modalities can help improve the diagnosis accuracy rate. Research is needed on the combination of modalities to discover multi-modal biomarkers.

  5. A comparison of spotlight synthetic aperture radar image formation techniques

    SciTech Connect

    Knittle, C.D.; Doren, N.E.; Jakowatz, C.V.

    1996-10-01

    Spotlight synthetic aperture radar images can be formed from the complex phase history data using two main techniques: (1) polar-to-cartesian interpolation followed by two-dimensional inverse Fourier transform (2DFFT), and (2) convolution backprojection (CBP). CBP has been widely used to reconstruct medical images in computer aided tomography, and only recently has been applied to form synthetic aperture radar imagery. It is alleged that CBP yields higher quality images because (1) all the Fourier data are used and (2) the polar formatted data is used directly to form a 2D Cartesian image and therefore 2D interpolation is not required. This report compares the quality of images formed by CBP and several modified versions of the 2DFFT method. We show from an image quality point of view that CBP is equivalent to first windowing the phase history data and then interpolating to an exscribed rectangle. From a mathematical perspective, we should expect this conclusion since the same Fourier data are used to form the SAR image. We next address the issue of parallel implementation of each algorithm. We dispute previous claims that CBP is more readily parallelizable than the 2DFFT method. Our conclusions are supported by comparing execution times between massively parallel implementations of both algorithms, showing that both experience similar decreases in computation time, but that CBP takes significantly longer to form an image.

  6. A Prototype Micro-Angiographic Fluoroscope and Its Application in Animal Studies

    PubMed Central

    Wu, Ye; Rudin, Stephen; Bednarek, Daniel R.

    2011-01-01

    In order to satisfy the high resolution (3 to 10 cycles/mm) imaging requirements in neurovascular image-guided interventional (IGI) procedures, a micro-angiographic fluoroscope (MAF) is being developed to enable both rapid sequence angiography (15 fps) at high exposure levels (hundreds of μR/frame) as well as fluoroscopy at high frame rates (30 fps) and low exposure levels (5 to 20 μR/frame). The prototype MAF consists of a 350-μm-thick CsI(Tl) scintillator coupled by a 2:1 fiber-optical taper to an 18 mm diameter variable-gain light image intensifier with two-stage microchannel plate (MCP) viewed by a 12-bit, 1024x1024, 30 fps CCD camera with digital interface board. The optical set-up enables variation of effective pixel-size from 31 to 50 micron. The first frame lag of the MAF in fluoroscopic 30 fps mode (2:1 binning) was less than 0.8% at exposures of 5-23 μR/frame. MTF, NPS, and DQE in angiographic mode were measured for IEC standard spectrum RQA 5. At spatial frequencies of 4 and 10 cycles/mm the MTF was 14% and 1.5%, and the DQE was 12% and 1.2%, respectively, while the DQE(0) was 60%. Acquisition software was developed to acquire 15 fps angiography and 30 fps fluoroscopy for real-time dark field and flat field correction or real-time roadmapping. Images obtained with the MAF in small animal IGI procedures are demonstrated. The linearity versus x-ray intensity and MCP working range effects has been studied. We plan to expand the current 3.6 cm diameter field of view to 6 cm in the next model of the MAF. PMID:21311727

  7. Molecular imaging of rheumatoid arthritis: emerging markers, tools, and techniques.

    PubMed

    Put, Stéphanie; Westhovens, René; Lahoutte, Tony; Matthys, Patrick

    2014-04-15

    Early diagnosis and effective monitoring of rheumatoid arthritis (RA) are important for a positive outcome. Instant treatment often results in faster reduction of inflammation and, as a consequence, less structural damage. Anatomical imaging techniques have been in use for a long time, facilitating diagnosis and monitoring of RA. However, mere imaging of anatomical structures provides little information on the processes preceding changes in synovial tissue, cartilage, and bone. Molecular imaging might facilitate more effective diagnosis and monitoring in addition to providing new information on the disease pathogenesis. A limiting factor in the development of new molecular imaging techniques is the availability of suitable probes. Here, we review which cells and molecules can be targeted in the RA joint and discuss the advances that have been made in imaging of arthritis with a focus on such molecular targets as folate receptor, F4/80, macrophage mannose receptor, E-selectin, intercellular adhesion molecule-1, phosphatidylserine, and matrix metalloproteinases. In addition, we discuss a new tool that is being introduced in the field, namely the use of nanobodies as tracers. Finally, we describe additional molecules displaying specific features in joint inflammation and propose these as potential new molecular imaging targets, more specifically receptor activator of nuclear factor κB and its ligand, chemokine receptors, vascular cell adhesion molecule-1, αVβ₃ integrin, P2X7 receptor, suppression of tumorigenicity 2, dendritic cell-specific transmembrane protein, and osteoclast-stimulatory transmembrane protein.

  8. Imaging through a biological medium using speckle noise removal techniques

    NASA Astrophysics Data System (ADS)

    Cuddihy, Aoife; Hennelly, Bryan; Naughton, Thomas J.; Markham, Charles; O'Neill, Raymond

    2007-07-01

    Experimental work has been carried out to extend a recently introduced technique, namely non-invasive optical imaging by speckle ensemble (NOISE), to non-invasively image a structure embedded beneath a 2.5mm thick layer of biological tissue (bacon). This method uses a microlens array and a coherent light source in transmission mode. Image reconstruction is achieved by averaging individual images from selected microlenses, thus reducing the speckle noise created due to the tissue layers. We advance on previous work by use of a more powerful laser source (75mW HeNe) and a higher resolution camera (2048x2048). Further advancement led to the introduction of a rotating ground glass diffuser into the system, which additionally reduced the speckle noise and enhanced the image quality. Leading on from this, an even simpler method of imaging beneath biological tissue is devised using the same setup, but without the microlens array. The principle is the same as the NOISE technique, except instead of taking a spatial average of independent speckle patterns a time average is taken within the exposure time of the CCD camera. Experimental results and comparisons are provided that support the theory.

  9. Planning/scheduling techniques for VQ-based image compression

    NASA Technical Reports Server (NTRS)

    Short, Nicholas M., Jr.; Manohar, Mareboyana; Tilton, James C.

    1994-01-01

    The enormous size of the data holding and the complexity of the information system resulting from the EOS system pose several challenges to computer scientists, one of which is data archival and dissemination. More than ninety percent of the data holdings of NASA is in the form of images which will be accessed by users across the computer networks. Accessing the image data in its full resolution creates data traffic problems. Image browsing using a lossy compression reduces this data traffic, as well as storage by factor of 30-40. Of the several image compression techniques, VQ is most appropriate for this application since the decompression of the VQ compressed images is a table lookup process which makes minimal additional demands on the user's computational resources. Lossy compression of image data needs expert level knowledge in general and is not straightforward to use. This is especially true in the case of VQ. It involves the selection of appropriate codebooks for a given data set and vector dimensions for each compression ratio, etc. A planning and scheduling system is described for using the VQ compression technique in the data access and ingest of raw satellite data.

  10. Further Developments of the Fringe-Imaging Skin Friction Technique

    NASA Technical Reports Server (NTRS)

    Zilliac, Gregory C.

    1996-01-01

    Various aspects and extensions of the Fringe-Imaging Skin Friction technique (FISF) have been explored through the use of several benchtop experiments and modeling. The technique has been extended to handle three-dimensional flow fields with mild shear gradients. The optical and imaging system has been refined and a PC-based application has been written that has made it possible to obtain high resolution skin friction field measurements in a reasonable period of time. The improved method was tested on a wingtip and compared with Navier-Stokes computations. Additionally, a general approach to interferogram-fringe spacing analysis has been developed that should have applications in other areas of interferometry. A detailed error analysis of the FISF technique is also included.

  11. Image Analysis Technique for Material Behavior Evaluation in Civil Structures.

    PubMed

    Speranzini, Emanuela; Marsili, Roberto; Moretti, Michele; Rossi, Gianluca

    2017-07-08

    The article presents a hybrid monitoring technique for the measurement of the deformation field. The goal is to obtain information about crack propagation in existing structures, for the purpose of monitoring their state of health. The measurement technique is based on the capture and analysis of a digital image set. Special markers were used on the surface of the structures that can be removed without damaging existing structures as the historical masonry. The digital image analysis was done using software specifically designed in Matlab to follow the tracking of the markers and determine the evolution of the deformation state. The method can be used in any type of structure but is particularly suitable when it is necessary not to damage the surface of structures. A series of experiments carried out on masonry walls of the Oliverian Museum (Pesaro, Italy) and Palazzo Silvi (Perugia, Italy) have allowed the validation of the procedure elaborated by comparing the results with those derived from traditional measuring techniques.

  12. Ambient Mass Spectrometry Imaging Using Direct Liquid Extraction Techniques

    SciTech Connect

    Laskin, Julia; Lanekoff, Ingela

    2015-11-13

    Mass spectrometry imaging (MSI) is a powerful analytical technique that enables label-free spatial localization and identification of molecules in complex samples.1-4 MSI applications range from forensics5 to clinical research6 and from understanding microbial communication7-8 to imaging biomolecules in tissues.1, 9-10 Recently, MSI protocols have been reviewed.11 Ambient ionization techniques enable direct analysis of complex samples under atmospheric pressure without special sample pretreatment.3, 12-16 In fact, in ambient ionization mass spectrometry, sample processing (e.g., extraction, dilution, preconcentration, or desorption) occurs during the analysis.17 This substantially speeds up analysis and eliminates any possible effects of sample preparation on the localization of molecules in the sample.3, 8, 12-14, 18-20 Venter and co-workers have classified ambient ionization techniques into three major categories based on the sample processing steps involved: 1) liquid extraction techniques, in which analyte molecules are removed from the sample and extracted into a solvent prior to ionization; 2) desorption techniques capable of generating free ions directly from substrates; and 3) desorption techniques that produce larger particles subsequently captured by an electrospray plume and ionized.17 This review focuses on localized analysis and ambient imaging of complex samples using a subset of ambient ionization methods broadly defined as “liquid extraction techniques” based on the classification introduced by Venter and co-workers.17 Specifically, we include techniques where analyte molecules are desorbed from solid or liquid samples using charged droplet bombardment, liquid extraction, physisorption, chemisorption, mechanical force, laser ablation, or laser capture microdissection. Analyte extraction is followed by soft ionization that generates ions corresponding to intact species. Some of the key advantages of liquid extraction techniques include the ease

  13. A dual-view digital tomosynthesis imaging technique for improved chest imaging

    SciTech Connect

    Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C.

    2015-09-15

    Purpose: Digital tomosynthesis (DTS) has been shown to be useful for reducing the overlapping of abnormalities with anatomical structures at various depth levels along the posterior–anterior (PA) direction in chest radiography. However, DTS provides crude three-dimensional (3D) images that have poor resolution in the lateral view and can only be displayed with reasonable quality in the PA view. Furthermore, the spillover of high-contrast objects from off-fulcrum planes generates artifacts that may impede the diagnostic use of the DTS images. In this paper, the authors describe and demonstrate the use of a dual-view DTS technique to improve the accuracy of the reconstructed volume image data for more accurate rendition of the anatomy and slice images with improved resolution and reduced artifacts, thus allowing the 3D image data to be viewed in views other than the PA view. Methods: With the dual-view DTS technique, limited angle scans are performed and projection images are acquired in two orthogonal views: PA and lateral. The dual-view projection data are used together to reconstruct 3D images using the maximum likelihood expectation maximization iterative algorithm. In this study, projection images were simulated or experimentally acquired over 360° using the scanning geometry for cone beam computed tomography (CBCT). While all projections were used to reconstruct CBCT images, selected projections were extracted and used to reconstruct single- and dual-view DTS images for comparison with the CBCT images. For realistic demonstration and comparison, a digital chest phantom derived from clinical CT images was used for the simulation study. An anthropomorphic chest phantom was imaged for the experimental study. The resultant dual-view DTS images were visually compared with the single-view DTS images and CBCT images for the presence of image artifacts and accuracy of CT numbers and anatomy and quantitatively compared with root-mean-square-deviation (RMSD) values

  14. Image encryption using a synchronous permutation-diffusion technique

    NASA Astrophysics Data System (ADS)

    Enayatifar, Rasul; Abdullah, Abdul Hanan; Isnin, Ismail Fauzi; Altameem, Ayman; Lee, Malrey

    2017-03-01

    In the past decade, the interest on digital images security has been increased among scientists. A synchronous permutation and diffusion technique is designed in order to protect gray-level image content while sending it through internet. To implement the proposed method, two-dimensional plain-image is converted to one dimension. Afterward, in order to reduce the sending process time, permutation and diffusion steps for any pixel are performed in the same time. The permutation step uses chaotic map and deoxyribonucleic acid (DNA) to permute a pixel, while diffusion employs DNA sequence and DNA operator to encrypt the pixel. Experimental results and extensive security analyses have been conducted to demonstrate the feasibility and validity of this proposed image encryption method.

  15. Rock porosity and fracture parameter estimation by image technique

    NASA Astrophysics Data System (ADS)

    Wang, W.; Wang, Ch. Z.; Hu, Y. Z.

    2009-06-01

    To estimate rock porosity in 2D and 3D, we used image technique to analyze rock fractures. We set up some models to characterize the rock fractures, based on the models, we used Best fit Ferret method to auto-determine fracture zone, then, analyze rock fracture porosities in 2-D and 3-D. In this study, rock sample is cut off into a number of slices of a certain thickness (18mm), then the fracture images are taken slice by slice both by using ultraviolet and visible lights, subsequently the fracture images are auto-thresholded into binary images, and fracture zones are determined by minimum circumscribed rectangles, finally the porosities are calculated in 2-D dimensional, and 3-D porosities are estimated based on 2-D porosity information.

  16. Quantitative Image Analysis Techniques with High-Speed Schlieren Photography

    NASA Technical Reports Server (NTRS)

    Pollard, Victoria J.; Herron, Andrew J.

    2017-01-01

    Optical flow visualization techniques such as schlieren and shadowgraph photography are essential to understanding fluid flow when interpreting acquired wind tunnel test data. Output of the standard implementations of these visualization techniques in test facilities are often limited only to qualitative interpretation of the resulting images. Although various quantitative optical techniques have been developed, these techniques often require special equipment or are focused on obtaining very precise and accurate data about the visualized flow. These systems are not practical in small, production wind tunnel test facilities. However, high-speed photography capability has become a common upgrade to many test facilities in order to better capture images of unsteady flow phenomena such as oscillating shocks and flow separation. This paper describes novel techniques utilized by the authors to analyze captured high-speed schlieren and shadowgraph imagery from wind tunnel testing for quantification of observed unsteady flow frequency content. Such techniques have applications in parametric geometry studies and in small facilities where more specialized equipment may not be available.

  17. An adaptive technique to maximize lossless image data compression of satellite images

    NASA Technical Reports Server (NTRS)

    Stewart, Robert J.; Lure, Y. M. Fleming; Liou, C. S. Joe

    1994-01-01

    Data compression will pay an increasingly important role in the storage and transmission of image data within NASA science programs as the Earth Observing System comes into operation. It is important that the science data be preserved at the fidelity the instrument and the satellite communication systems were designed to produce. Lossless compression must therefore be applied, at least, to archive the processed instrument data. In this paper, we present an analysis of the performance of lossless compression techniques and develop an adaptive approach which applied image remapping, feature-based image segmentation to determine regions of similar entropy and high-order arithmetic coding to obtain significant improvements over the use of conventional compression techniques alone. Image remapping is used to transform the original image into a lower entropy state. Several techniques were tested on satellite images including differential pulse code modulation, bi-linear interpolation, and block-based linear predictive coding. The results of these experiments are discussed and trade-offs between computation requirements and entropy reductions are used to identify the optimum approach for a variety of satellite images. Further entropy reduction can be achieved by segmenting the image based on local entropy properties then applying a coding technique which maximizes compression for the region. Experimental results are presented showing the effect of different coding techniques for regions of different entropy. A rule-base is developed through which the technique giving the best compression is selected. The paper concludes that maximum compression can be achieved cost effectively and at acceptable performance rates with a combination of techniques which are selected based on image contextual information.

  18. 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

  19. Comparison and evaluation of retrospective intermodality image registration techniques

    NASA Astrophysics Data System (ADS)

    West, Jay B.; Fitzpatrick, J. Michael; Wang, Matthew Y.; Dawant, Benoit M.; Maurer, Calvin R., Jr.; Kessler, Robert M.; Maciunas, Robert J.; Barillot, Christian; Lemoine, Didier; Collignon, Andre M. F.; Maes, Frederik; Suetens, Paul; Vandermeulen, Dirk; van den Elsen, Petra A.; Hemler, Paul F.; Napel, Sandy; Sumanaweera, Thilaka S.; Harkness, Beth A.; Hill, Derek L.; Studholme, Colin; Malandain, Gregoire; Pennec, Xavier; Noz, Marilyn E.; Maguire, Gerald Q., Jr.; Pollack, Michael; Pelizzari, Charles A.; Robb, Richard A.; Hanson, Dennis P.; Woods, Roger P.

    1996-04-01

    All retrospective image registration methods have attached to them some intrinsic estimate of registration error. However, this estimate of accuracy may not always be a good indicator of the distance between actual and estimated positions of targets within the cranial cavity. This paper describes a project whose principal goal is to use a prospective method based on fiducial markers as a 'gold standard' to perform an objective, blinded evaluation of the accuracy of several retrospective image-to-image registration techniques. Image volumes of three modalities -- CT, MR, and PET -- were taken of patients undergoing neurosurgery at Vanderbilt University Medical Center. These volumes had all traces of the fiducial markers removed, and were provided to project collaborators outside Vanderbilt, who then performed retrospective registrations on the volumes, calculating transformations from CT to MR and/or from PET to MR, and communicated their transformations to Vanderbilt where the accuracy of each registration was evaluated. In this evaluation the accuracy is measured at multiple 'regions of interest,' i.e. areas in the brain which would commonly be areas of neurological interest. A region is defined in the MR image and its centroid C is determined. Then the prospective registration is used to obtain the corresponding point C' in CT or PET. To this point the retrospective registration is then applied, producing C' in MR. Statistics are gathered on the target registration error (TRE), which is the disparity between the original point C and its corresponding point C'. A second goal of the project is to evaluate the importance of correcting geometrical distortion in MR images, by comparing the retrospective TRE in the rectified images, i.e., those which have had the distortion correction applied, with that of the same images before rectification. This paper presents preliminary results of this study along with a brief description of each registration technique and an

  20. Surface conversion techniques for low energy neutral atom imagers

    NASA Technical Reports Server (NTRS)

    Quinn, J. M.

    1995-01-01

    This investigation has focused on development of key technology elements for low energy neutral atom imaging. More specifically, we have investigated the conversion of low energy neutral atoms to negatively charged ions upon reflection from specially prepared surfaces. This 'surface conversion' technique appears to offer a unique capability of detecting, and thus imaging, neutral atoms at energies of 0.01 - 1 keV with high enough efficiencies to make practical its application to low energy neutral atom imaging in space. Such imaging offers the opportunity to obtain the first instantaneous global maps of macroscopic plasma features and their temporal variation. Through previous in situ plasma measurements, we have a statistical picture of large scale morphology and local measurements of dynamic processes. However, with in situ techniques it is impossible to characterize or understand many of the global plasma transport and energization processes. A series of global plasma images would greatly advance our understanding of these processes and would provide the context for interpreting previous and future in situ measurements. Fast neutral atoms, created from ions that are neutralized in collisions with exospheric neutrals, offer the means for remotely imaging plasma populations. Energy and mass analysis of these neutrals provides critical information about the source plasma distribution. The flux of neutral atoms available for imaging depends upon a convolution of the ambient plasma distribution with the charge exchange cross section for the background neutral population. Some of the highest signals are at relatively low energies (well below 1 keV). This energy range also includes some of the most important plasma populations to be imaged, for example the base of the cleft ion fountain.

  1. Analysis of High Contrast Imaging Techniques for Space Based Direct Planetary Imaging

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.; Gezari, Dan Y.; Nisenson, P.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    We report on our ongoing investigations of a number of techniques for direct detection and imaging of Earth-like planets around nearby stellar sources. Herein, we give a quantitative analysis of these techniques and compare and contrast them via computer simulations. The techniques we will be reporting on are Bracewell Interferometry, Nisenson Apodized Square Aperture, and Coronagraphic masking techniques. We parameterize our results with respect to wavelength, aperture size, effects of mirror speckle, both mid- and high-spatial frequency, detector and photon noise as well pointing error. The recent numerous detections of Jupiter and Saturn like planets has driven a resurgence in research of space based high contrast imaging techniques for direct planetary imaging. Work is currently ongoing for concepts for NASA's Terrestrial Planet Finder mission and a number of study teams have been funded. The authors are members of one team.

  2. Comparison of sonochemiluminescence images using image analysis techniques and identification of acoustic pressure fields via simulation.

    PubMed

    Tiong, T Joyce; Chandesa, Tissa; Yap, Yeow Hong

    2017-05-01

    One common method to determine the existence of cavitational activity in power ultrasonics systems is by capturing images of sonoluminescence (SL) or sonochemiluminescence (SCL) in a dark environment. Conventionally, the light emitted from SL or SCL was detected based on the number of photons. Though this method is effective, it could not identify the sonochemical zones of an ultrasonic systems. SL/SCL images, on the other hand, enable identification of 'active' sonochemical zones. However, these images often provide just qualitative data as the harvesting of light intensity data from the images is tedious and require high resolution images. In this work, we propose a new image analysis technique using pseudo-colouring images to quantify the SCL zones based on the intensities of the SCL images and followed by comparison of the active SCL zones with COMSOL simulated acoustic pressure zones.

  3. Image segmentation using common techniques and illumination applied to tissue culture

    NASA Astrophysics Data System (ADS)

    Vazquez Rueda, Martin G.; Hahn, Federico

    1998-03-01

    This paper present the comparation and performance on no adaptive image segmentation techniques using illumination and adaptive image segmentation techniques. Results obtained on indoor plant reproduction by tissue culture, show the improve in time process, simplify the image segmentation process, experimental results are presented using common techniques in image processing and illumination, contrasted with adaptive image segmentation.

  4. Multivariate image processing technique for noninvasive glucose sensing

    NASA Astrophysics Data System (ADS)

    Webb, Anthony J.; Cameron, Brent D.

    2010-02-01

    A potential noninvasive glucose sensing technique was investigated for application towards in vivo glucose monitoring for individuals afflicted with diabetes mellitus. Three dimensional ray tracing simulations using a realistic iris pattern integrated into an advanced human eye model are reported for physiological glucose concentrations ranging between 0 to 500 mg/dL. The anterior chamber of the human eye contains a clear fluid known as the aqueous humor. The optical refractive index of the aqueous humor varies on the order of 1.5x10-4 for a change in glucose concentration of 100 mg/dL. The simulation data was analyzed with a developed multivariate chemometrics procedure that utilizes iris-based images to form a calibration model. Results from these simulations show considerable potential for use of the developed method in the prediction of glucose. For further demonstration, an in vitro eye model was developed to validate the computer based modeling technique. In these experiments, a realistic iris pattern was placed in an analog eye model in which the glucose concentration within the fluid representing the aqueous humor was varied. A series of high resolution digital images were acquired using an optical imaging system. These images were then used to form an in vitro calibration model utilizing the same multivariate chemometric technique demonstrated in the 3-D optical simulations. In general, the developed method exhibits considerable applicability towards its use as an in vivo platform for the noninvasive monitoring of physiological glucose concentration.

  5. Improving image classification in a complex wetland ecosystem through image fusion techniques

    NASA Astrophysics Data System (ADS)

    Kumar, Lalit; Sinha, Priyakant; Taylor, Subhashni

    2014-01-01

    The aim of this study was to evaluate the impact of image fusion techniques on vegetation classification accuracies in a complex wetland system. Fusion of panchromatic (PAN) and multispectral (MS) Quickbird satellite imagery was undertaken using four image fusion techniques: Brovey, hue-saturation-value (HSV), principal components (PC), and Gram-Schmidt (GS) spectral sharpening. These four fusion techniques were compared in terms of their mapping accuracy to a normal MS image using maximum-likelihood classification (MLC) and support vector machine (SVM) methods. Gram-Schmidt fusion technique yielded the highest overall accuracy and kappa value with both MLC (67.5% and 0.63, respectively) and SVM methods (73.3% and 0.68, respectively). This compared favorably with the accuracies achieved using the MS image. Overall, improvements of 4.1%, 3.6%, 5.8%, 5.4%, and 7.2% in overall accuracies were obtained in case of SVM over MLC for Brovey, HSV, GS, PC, and MS images, respectively. Visual and statistical analyses of the fused images showed that the Gram-Schmidt spectral sharpening technique preserved spectral quality much better than the principal component, Brovey, and HSV fused images. Other factors, such as the growth stage of species and the presence of extensive background water in many parts of the study area, had an impact on classification accuracies.

  6. Applicability of three-dimensional imaging techniques in fetal medicine*

    PubMed Central

    Werner Júnior, Heron; dos Santos, Jorge Lopes; Belmonte, Simone; Ribeiro, Gerson; Daltro, Pedro; Gasparetto, Emerson Leandro; Marchiori, Edson

    2016-01-01

    Objective To generate physical models of fetuses from images obtained with three-dimensional ultrasound (3D-US), magnetic resonance imaging (MRI), and, occasionally, computed tomography (CT), in order to guide additive manufacturing technology. Materials and Methods We used 3D-US images of 31 pregnant women, including 5 who were carrying twins. If abnormalities were detected by 3D-US, both MRI and in some cases CT scans were then immediately performed. The images were then exported to a workstation in DICOM format. A single observer performed slice-by-slice manual segmentation using a digital high resolution screen. Virtual 3D models were obtained from software that converts medical images into numerical models. Those models were then generated in physical form through the use of additive manufacturing techniques. Results Physical models based upon 3D-US, MRI, and CT images were successfully generated. The postnatal appearance of either the aborted fetus or the neonate closely resembled the physical models, particularly in cases of malformations. Conclusion The combined use of 3D-US, MRI, and CT could help improve our understanding of fetal anatomy. These three screening modalities can be used for educational purposes and as tools to enable parents to visualize their unborn baby. The images can be segmented and then applied, separately or jointly, in order to construct virtual and physical 3D models. PMID:27818540

  7. Comparison of additive image fusion vs. feature-level image fusion techniques for enhanced night driving

    NASA Astrophysics Data System (ADS)

    Bender, Edward J.; Reese, Colin E.; Van Der Wal, Gooitzen S.

    2003-02-01

    The Night Vision & Electronic Sensors Directorate (NVESD) has conducted a series of image fusion evaluations under the Head-Tracked Vision System (HTVS) program. The HTVS is a driving system for both wheeled and tracked military vehicles, wherein dual-waveband sensors are directed in a more natural head-slewed imaging mode. The HTVS consists of thermal and image-intensified TV sensors, a high-speed gimbal, a head-mounted display, and a head tracker. A series of NVESD field tests over the past two years has investigated the degree to which additive (A+B) image fusion of these sensors enhances overall driving performance. Additive fusion employs a single (but user adjustable) fractional weighting for all the features of each sensor's image. More recently, NVESD and Sarnoff Corporation have begun a cooperative effort to evaluate and refine Sarnoff's "feature-level" multi-resolution (pyramid) algorithms for image fusion. This approach employs digital processing techniques to select at each image point only the sensor with the strongest features, and to utilize only those features to reconstruct the fused video image. This selection process is performed simultaneously at multiple scales of the image, which are combined to form the reconstructed fused image. All image fusion techniques attempt to combine the "best of both sensors" in a single image. Typically, thermal sensors are better for detecting military threats and targets, while image-intensified sensors provide more natural scene cues and detect cultural lighting. This investigation will address the differences between additive fusion and feature-level image fusion techniques for enhancing the driver's overall situational awareness.

  8. Image processing of correlated data by experimental design techniques

    SciTech Connect

    Stern, D.

    1987-01-01

    New classes of algorithms are developed for processing of two-dimensional image data imbedded in correlated noise. The algorithms are based on modifications of standard analysis of variance (ANOVA) techniques ensuring their proper operation in dependent noise. The approach taken in the development of procedures is deductive. First, the theory of modified ANOVA (MANOVA) techniques involving one- and two-way layouts are considered for noise models with autocorrelation matrix (ACM) formed by direct multiplication of rows and columns or tensored correlation matrices (TCM) stressing the special case of the first-order Markov process. Next, the techniques are generalized to include arbitrary, wide-sense stationary (WSS) processes. This permits dealing with diagonal masks which have ACM of a general form even for TCM. As further extension, the theory of Latin square (LS) masks is generalized to include dependent noise with TCM. This permits dealing with three different effects of m levels using only m{sup 2} observations rather than m{sup 3}. Since in many image-processing problems, replication of data is possible, the masking techniques are generalized to replicated data for which the replication is TCM dependent. For all procedures developed, algorithms are implemented which ensure real-time processing of images.

  9. Assessment of banana fruit maturity by image processing technique.

    PubMed

    Surya Prabha, D; Satheesh Kumar, J

    2015-03-01

    Maturity stage of fresh banana fruit is an important factor that affects the fruit quality during ripening and marketability after ripening. The ability to identify maturity of fresh banana fruit will be a great support for farmers to optimize harvesting phase which helps to avoid harvesting either under-matured or over-matured banana. This study attempted to use image processing technique to detect the maturity stage of fresh banana fruit by its color and size value of their images precisely. A total of 120 images comprising 40 images from each stage such as under-mature, mature and over-mature were used for developing algorithm and accuracy prediction. The mean color intensity from histogram; area, perimeter, major axis length and minor axis length from the size values, were extracted from the calibration images. Analysis of variance between each maturity stage on these features indicated that the mean color intensity and area features were more significant in predicting the maturity of banana fruit. Hence, two classifier algorithms namely, mean color intensity algorithm and area algorithm were developed and their accuracy on maturity detection was assessed. The mean color intensity algorithm showed 99.1 % accuracy in classifying the banana fruit maturity. The area algorithm classified the under-mature fruit at 85 % accuracy. Hence the maturity assessment technique proposed in this paper could be used commercially to develop a field based complete automatic detection system to take decision on the right time of harvest by the banana growers.

  10. Dual self-image technique for beam collimation

    NASA Astrophysics Data System (ADS)

    Herrera-Fernandez, Jose Maria; Sanchez-Brea, Luis Miguel; Torcal-Milla, Francisco Jose; Morlanes, Tomas; Bernabeu, Eusebio

    2016-07-01

    We propose an accurate technique for obtaining highly collimated beams, which also allows testing the collimation degree of a beam. It is based on comparing the period of two different self-images produced by a single diffraction grating. In this way, variations in the period of the diffraction grating do not affect to the measuring procedure. Self-images are acquired by two CMOS cameras and their periods are determined by fitting the variogram function of the self-images to a cosine function with polynomial envelopes. This way, loss of accuracy caused by imperfections of the measured self-images is avoided. As usual, collimation is obtained by displacing the collimation element with respect to the source along the optical axis. When the period of both self-images coincides, collimation is achieved. With this method neither a strict control of the period of the diffraction grating nor a transverse displacement, required in other techniques, are necessary. As an example, a LED considering paraxial approximation and point source illumination is collimated resulting a resolution in the divergence of the beam of δ φ =+/- 1.57 μ {rad}.

  11. Imaging technique for washed-out ink inscriptions on vellum

    NASA Astrophysics Data System (ADS)

    Kovalchuk, Alexander

    2011-09-01

    An imaging technique that had been developed for reading destroyed texts in an ancient manuscript is described. A codex of early Peshitta Gospels was examined. The leaves of the codex were made of vellum. Texts were inscribed with black and red iron based inks. The codex suffered extensive damage from a prolonged exposure to water. The black ink was completely washed off from the majority of the pages. Multispectral imaging showed no detectable traces of ink in the pores of the vellum. It was discovered that the vellum retains "memory" of the long gone inscriptions. It has been shown that in oblique illumination a ratio of reflected to absorbed light differs for areas of vellum at which the ink once was applied and the areas which were never covered with ink. Experiments have been carried out for finding the optimal polarisation and spectral characteristics of light to be used for illumination of the surface of vellum as well as the best angles of incidence of light and angle of observation. A device for imaging folios of the water damaged Peshitta codex have been designed and the algorithms for processing the raw images have been developed. Application of the our imaging technique has allowed reading completely destroyed ink inscriptions of the invaluable historic artefact.

  12. Imaging technique for washed-out ink inscriptions on vellum

    NASA Astrophysics Data System (ADS)

    Kovalchuk, Alexander

    2012-01-01

    An imaging technique that had been developed for reading destroyed texts in an ancient manuscript is described. A codex of early Peshitta Gospels was examined. The leaves of the codex were made of vellum. Texts were inscribed with black and red iron based inks. The codex suffered extensive damage from a prolonged exposure to water. The black ink was completely washed off from the majority of the pages. Multispectral imaging showed no detectable traces of ink in the pores of the vellum. It was discovered that the vellum retains "memory" of the long gone inscriptions. It has been shown that in oblique illumination a ratio of reflected to absorbed light differs for areas of vellum at which the ink once was applied and the areas which were never covered with ink. Experiments have been carried out for finding the optimal polarisation and spectral characteristics of light to be used for illumination of the surface of vellum as well as the best angles of incidence of light and angle of observation. A device for imaging folios of the water damaged Peshitta codex have been designed and the algorithms for processing the raw images have been developed. Application of the our imaging technique has allowed reading completely destroyed ink inscriptions of the invaluable historic artefact.

  13. Positron imaging techniques for process engineering: recent developments at Birmingham

    NASA Astrophysics Data System (ADS)

    Parker, D. J.; Leadbeater, T. W.; Fan, X.; Hausard, M. N.; Ingram, A.; Yang, Z.

    2008-09-01

    For over 20 years the University of Birmingham has been using positron-emitting radioactive tracers to study engineering processes. The imaging technique of positron emission tomography (PET), widely used for medical applications, has been adapted for these studies, and the complementary technique of positron emission particle tracking (PEPT) has been developed. The radioisotopes are produced using the Birmingham MC40 cyclotron, and a variety of techniques are employed to produce suitable tracers in a wide range of forms. Detectors originally designed for medical use have been modified for engineering applications, allowing measurements to be made on real process equipment, at laboratory or pilot plant scale. This paper briefly reviews the capability of the techniques and introduces a few of the many processes to which they have been applied.

  14. The Handbook of Medical Image Perception and Techniques

    NASA Astrophysics Data System (ADS)

    Samei, Ehsan; Krupinski, Elizabeth

    2009-12-01

    Peter Ayton; Part V. Optimization and Practical Issues: 25. Optimization of 2D and 3D radiographic systems Jeff Siewerdson; 26. Applications of AFC methodology in optimization of CT imaging systems Kent Ogden and Walter Huda; 27. Perceptual issues in reading mammograms Margarita Zuley; 28. Perceptual optimization of display processing techniques Richard Van Metter; 29. Optimization of display systems Elizabeth Krupinski and Hans Roehrig; 30. Ergonomic radiologist workplaces in the PACS environment Carl Zylack; Part VI. Epilogue: 31. Future prospects of medical image perception Ehsan Samei and Elizabeth Krupinski; Index.

  15. The Handbook of Medical Image Perception and Techniques

    NASA Astrophysics Data System (ADS)

    Samei, Ehsan; Krupinski, Elizabeth

    2014-07-01

    Peter Ayton; Part V. Optimization and Practical Issues: 25. Optimization of 2D and 3D radiographic systems Jeff Siewerdson; 26. Applications of AFC methodology in optimization of CT imaging systems Kent Ogden and Walter Huda; 27. Perceptual issues in reading mammograms Margarita Zuley; 28. Perceptual optimization of display processing techniques Richard Van Metter; 29. Optimization of display systems Elizabeth Krupinski and Hans Roehrig; 30. Ergonomic radiologist workplaces in the PACS environment Carl Zylack; Part VI. Epilogue: 31. Future prospects of medical image perception Ehsan Samei and Elizabeth Krupinski; Index.

  16. Scene correction (precision techniques) of ERTS sensor data using digital image processing techniques

    NASA Technical Reports Server (NTRS)

    Bernstein, R.

    1974-01-01

    Techniques have been developed, implemented, and evaluated to process ERTS Return Beam Vidicon (RBV) and Multispectral Scanner (MSS) sensor data using digital image processing techniques. The RBV radiometry has been corrected to remove shading effects, and the MSS geometry and radiometry have been corrected to remove internal and external radiometric and geometric errors. The results achieved show that geometric mapping accuracy of about one picture element RMS and two picture elements (maximum) can be achieved by the use of nine ground control points. Radiometric correction of MSS and RBV sensor data has been performed to eliminate striping and shading effects to about one count accuracy. Image processing times on general purpose computers of the IBM 370/145 to 168 class are in the range of 29 to 3.2 minutes per MSS scene (4 bands). Photographic images of the fully corrected and annotated scenes have been generated from the processed data and have demonstrated excellent quality and information extraction potential.

  17. Computer image processing - The Viking experience. [digital enhancement techniques

    NASA Technical Reports Server (NTRS)

    Green, W. B.

    1977-01-01

    Computer processing of digital imagery from the Viking mission to Mars is discussed, with attention given to subjective enhancement and quantitative processing. Contrast stretching and high-pass filtering techniques of subjective enhancement are described; algorithms developed to determine optimal stretch and filtering parameters are also mentioned. In addition, geometric transformations to rectify the distortion of shapes in the field of view and to alter the apparent viewpoint of the image are considered. Perhaps the most difficult problem in quantitative processing of Viking imagery was the production of accurate color representations of Orbiter and Lander camera images.

  18. Application of digital image processing techniques to astronomical imagery, 1979

    NASA Technical Reports Server (NTRS)

    Lorre, J. J.

    1979-01-01

    Several areas of applications of image processing to astronomy were identified and discussed. These areas include: (1) deconvolution for atmospheric seeing compensation; a comparison between maximum entropy and conventional Wiener algorithms; (2) polarization in galaxies from photographic plates; (3) time changes in M87 and methods of displaying these changes; (4) comparing emission line images in planetary nebulae; and (5) log intensity, hue saturation intensity, and principal component color enhancements of M82. Examples are presented of these techniques applied to a variety of objects.

  19. Reduction and analysis techniques for infrared imaging data

    NASA Technical Reports Server (NTRS)

    Mccaughrean, Mark

    1989-01-01

    Infrared detector arrays are becoming increasingly available to the astronomy community, with a number of array cameras already in use at national observatories, and others under development at many institutions. As the detector technology and imaging instruments grow more sophisticated, more attention is focussed on the business of turning raw data into scientifically significant information. Turning pictures into papers, or equivalently, astronomy into astrophysics, both accurately and efficiently, is discussed. Also discussed are some of the factors that can be considered at each of three major stages; acquisition, reduction, and analysis, concentrating in particular on several of the questions most relevant to the techniques currently applied to near infrared imaging.

  20. Computer image processing - The Viking experience. [digital enhancement techniques

    NASA Technical Reports Server (NTRS)

    Green, W. B.

    1977-01-01

    Computer processing of digital imagery from the Viking mission to Mars is discussed, with attention given to subjective enhancement and quantitative processing. Contrast stretching and high-pass filtering techniques of subjective enhancement are described; algorithms developed to determine optimal stretch and filtering parameters are also mentioned. In addition, geometric transformations to rectify the distortion of shapes in the field of view and to alter the apparent viewpoint of the image are considered. Perhaps the most difficult problem in quantitative processing of Viking imagery was the production of accurate color representations of Orbiter and Lander camera images.

  1. Application of image processing techniques to gamma-angiography.

    PubMed

    Romary, D; Lerallut, J F; Fontenier, G

    1985-10-01

    Different image processing techniques have been tested and compared on data derived from gamma-angiography images to detect the boundary of the left ventricle. The method involves a preprocessing step, followed by the edge detection itself. The best preprocessing is a nonlinear "variant" filtering, where each pixel is replaced by the average of the 3 X 3 neighborhood having the smallest variance. The edge detector giving the best contour is a Sobel operator. A second-order high-pass Butterworth filter also provides a good segmentation.

  2. New techniques for imaging and analyzing lung tissue.

    PubMed Central

    Roggli, V L; Ingram, P; Linton, R W; Gutknecht, W F; Mastin, P; Shelburne, J D

    1984-01-01

    The recent technological revolution in the field of imaging techniques has provided pathologists and toxicologists with an expanding repertoire of analytical techniques for studying the interaction between the lung and the various exogenous materials to which it is exposed. Analytical problems requiring elemental sensitivity or specificity beyond the range of that offered by conventional scanning electron microscopy and energy dispersive X-ray analysis are particularly appropriate for the application of these newer techniques. Electron energy loss spectrometry, Auger electron spectroscopy, secondary ion mass spectrometry, and laser microprobe mass analysis each offer unique advantages in this regard, but also possess their own limitations and disadvantages. Diffraction techniques provide crystalline structural information available through no other means. Bulk chemical techniques provide useful cross-checks on the data obtained by microanalytical approaches. It is the purpose of this review to summarize the methodology of these techniques, acknowledge situations in which they have been used in addressing problems in pulmonary toxicology, and comment on the relative advantages and disadvantages of each approach. It is necessary for an investigator to weigh each of these factors when deciding which technique is best suited for any given analytical problem; often it is useful to employ a combination of two or more of the techniques discussed. It is anticipated that there will be increasing utilization of these technologies for problems in pulmonary toxicology in the decades to come. Images FIGURE 3. A FIGURE 3. B FIGURE 3. C FIGURE 3. D FIGURE 4. FIGURE 5. FIGURE 7. A FIGURE 7. B FIGURE 8. A FIGURE 8. B FIGURE 8. C FIGURE 9. A FIGURE 9. B FIGURE 10. PMID:6090115

  3. Percutaneous Management of Accidentally Retained Foreign Bodies During Image-Guided Non-vascular Procedures: Novel Technique Using a Large-Bore Biopsy System.

    PubMed

    Cazzato, Roberto Luigi; Garnon, Julien; Ramamurthy, Nitin; Tsoumakidou, Georgia; Caudrelier, Jean; Thénint, Marie-Aude; Rao, Pramod; Koch, Guillaume; Gangi, Afshin

    2016-07-01

    To describe a novel percutaneous image-guided technique using a large-bore biopsy system to retrieve foreign bodies (FBs) accidentally retained during non-vascular interventional procedures. Between May 2013 and October 2015, five patients underwent percutaneous retrieval of five iatrogenic FBs, including a biopsy needle tip in the femoral head following osteoblastoma biopsy and radiofrequency ablation (RFA); a co-axial needle shaft within a giant desmoid tumour following cryoablation; and three post-vertebroplasty cement tails within paraspinal muscles. All FBs were retrieved immediately following original procedures under local or general anaesthesia, using combined computed tomography (CT) and fluoroscopic guidance. The basic technique involved positioning a 6G trocar sleeve around the FB long axis and co-axially advancing an 8G biopsy needle to retrieve the FB within the biopsy core. Retrospective chart review facilitated analysis of procedures, FBs, technical success, and complications. Mean FB size was 23 mm (range 8-74 mm). Four FBs were located within 10 mm of non-vascular significant anatomic structures. The basic technique was successful in 3 cases; 2 cases required technical modifications including using a stiff guide-wire to facilitate retrieval in the case of the post-cryoablation FB; and using the central mandrin of the 6G trocar to push a cement tract back into an augmented vertebra when initial retrieval failed. Overall technical success (FB retrieval or removal to non-hazardous location) was 100 %, with no complications. Percutaneous image-guided retrieval of iatrogenic FBs using a large-bore biopsy system is a feasible, safe, effective, and versatile technique, with potential advantages over existing methods.

  4. Adapting content-based image retrieval techniques for the semantic annotation of medical images.

    PubMed

    Kumar, Ashnil; Dyer, Shane; Kim, Jinman; Li, Changyang; Leong, Philip H W; Fulham, Michael; Feng, Dagan

    2016-04-01

    The automatic annotation of medical images is a prerequisite for building comprehensive semantic archives that can be used to enhance evidence-based diagnosis, physician education, and biomedical research. Annotation also has important applications in the automatic generation of structured radiology reports. Much of the prior research work has focused on annotating images with properties such as the modality of the image, or the biological system or body region being imaged. However, many challenges remain for the annotation of high-level semantic content in medical images (e.g., presence of calcification, vessel obstruction, etc.) due to the difficulty in discovering relationships and associations between low-level image features and high-level semantic concepts. This difficulty is further compounded by the lack of labelled training data. In this paper, we present a method for the automatic semantic annotation of medical images that leverages techniques from content-based image retrieval (CBIR). CBIR is a well-established image search technology that uses quantifiable low-level image features to represent the high-level semantic content depicted in those images. Our method extends CBIR techniques to identify or retrieve a collection of labelled images that have similar low-level features and then uses this collection to determine the best high-level semantic annotations. We demonstrate our annotation method using retrieval via weighted nearest-neighbour retrieval and multi-class classification to show that our approach is viable regardless of the underlying retrieval strategy. We experimentally compared our method with several well-established baseline techniques (classification and regression) and showed that our method achieved the highest accuracy in the annotation of liver computed tomography (CT) images.

  5. Single-image rectification technique in forensic science.

    PubMed

    González-Jorge, Higinio; Puente, Iván; Eguía, Pablo; Arias, Pedro

    2013-03-01

    Many researchers have been working in Spain to document the communal graves of those assassinated during the Spanish Civil War. This article shows the results obtained with two low-cost photogrammetric techniques for the basic documentation of forensic studies. These low-cost techniques are based on single-image rectification and the correction of the original photo displacement due to the projection and perspective distortions introduced by the lens of the camera. The capability of image rectification is tested in an excavation in the village of Loma de Montija (Burgos, Spain). The results of both techniques are compared with the more accurate data obtained from a laser scanner system RIEGL LMS-Z390i to evaluate the error in the lengths. The first technique uses a camera situated on a triangle-shaped pole at a height of 5 m and the second positions the camera over the grave using a linearly actuated device. The first technique shows measurement errors less than 6%, whereas the second shows greater errors (between 8% and 14%) owing to the positioning of the carbon-fiber cross on an uneven surface. © 2013 American Academy of Forensic Sciences.

  6. Use of image analyzer technique to validate bivalve embryo bioassays

    SciTech Connect

    Uiniou, F.; Goraguer, H.; Quiniou, L.

    1995-12-31

    Bivalve bioassays are based on visual observation of normal and abnormal D larvae. This qualitative and morphological criteria is long and time-consuming. Moreover, this work needs to be performed by the same person to avoid the human discrepancy. This study shows how the image analyzer technique, based only on measurements, without shape recognition, allows the assessment of the dose-response effect of a toxic compound regardless of scientific evaluation. Furthermore, by this technique, geometrical features of the larvae permit the observation, at very low concentrations, of a hormetic effect visually undetectable.

  7. Astronomical imaging by filtered weighted-shift-and-add technique

    NASA Technical Reports Server (NTRS)

    Ribak, Erez

    1986-01-01

    The weighted-shift-and-add speckle imaging technique is analyzed using simple assumptions. The end product is shown to be a convolution of the object with a typical point-spread function (psf) that is similar in shape to the telescope psf and depends marginally on the speckle psf. A filter can be applied to each data frame before locating the maxima, either to identify the speckle locations (matched filter) or to estimate the instantaneous atmospheric psf (Wiener filter). Preliminary results show the power of the technique when applied to photon-limited data and to extended objects.

  8. Applications of Indirect Imaging Techniques in X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Harlaftis, E. T.

    A review is given on aspects of indirect imaging techniques in X-ray binaries which are used as diagnostics tools for probing the X-ray dominated accretion disc physics. These techniques utilize observed properties such as the emission line profile variability, the time delays between simultaneous optical/X-ray light curves, the light curves of eclipsing systems and the pulsed emission from the compact object in order to reconstruct the accretion disc's line emissivity (Doppler tomography), the irradiated disc and heated secondary (echo mapping), the outer disc structure (modified eclipse mapping) and the accreting regions onto the compact object, respectively.

  9. [Noninvasive imaging techniques to study coronary artery aneurysms].

    PubMed

    de Agustín, J A; Marcos-Alberca, P; Fernández-Golfín, C; Bordes, S; Pozo, E; Macaya, C; Zamorano, J

    2012-01-01

    Given the growing evidence about the use of membrane-covered stents to treat coronary artery aneurysms, it is fundamental to know the exact anatomy of the aneurysm to enable patients to be selected correctly. Invasive heart catheterization has limitations for diagnostic purposes and can underestimate the size of the aneurysm. In this article, we review the noninvasive diagnostic imaging techniques for the study of coronary artery aneurysms, illustrating the usefulness of each technique. Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.

  10. Fluoroscopic guide to an ideal implant position for Sapien XT and CoreValve during a valve-in-valve procedure.

    PubMed

    Bapat, Vinnie N; Attia, Rizwan Q; Condemi, Fortunata; Visagan, Ravi; Guthrie, Maya; Sunni, Shelina; Thomas, Martyn

    2013-11-01

    This study sought to provide a guide to the fluoroscopic appearances of various valve-in-valve (VIV) combinations by deploying a transcatheter heart valve (THV) within a degenerated surgical heart valve (SHV) in an ideal position. VIV procedures are being increasingly performed with substantial experience acquired in treating degenerated SHV in the aortic position with Sapien/Sapien XT (Edwards Lifesciences Ltd., Irvine, California) and CoreValve/Evolute (Medtronic Inc., Minneapolis, Minnesota) valves. Although less invasive than conventional surgery, securing the THV in an optimal position within the SHV determines the success of this novel treatment. For VIV implantation, we selected appropriate Sapien XT and CoreValve/Evolute sizes dependin