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Sample records for ct medical image

  1. Plot of virtual surgery based on CT medical images

    NASA Astrophysics Data System (ADS)

    Song, Limei; Zhang, Chunbo

    2009-10-01

    Although the CT device can give the doctors a series of 2D medical images, it is difficult to give vivid view for the doctors to acknowledge the decrease part. In order to help the doctors to plot the surgery, the virtual surgery system is researched based on the three-dimensional visualization technique. After the disease part of the patient is scanned by the CT device, the 3D whole view will be set up based on the 3D reconstruction module of the system. TCut a part is the usually used function for doctors in the real surgery. A curve will be created on the 3D space; and some points can be added on the curve automatically or manually. The position of the point can change the shape of the cut curves. The curve can be adjusted by controlling the points. If the result of the cut function is not satisfied, all the operation can be cancelled to restart. The flexible virtual surgery gives more convenience to the real surgery. Contrast to the existing medical image process system, the virtual surgery system is added to the system, and the virtual surgery can be plotted for a lot of times, till the doctors have enough confidence to start the real surgery. Because the virtual surgery system can give more 3D information of the disease part, some difficult surgery can be discussed by the expert doctors in different city via internet. It is a useful function to understand the character of the disease part, thus to decrease the surgery risk.

  2. Edge extraction of CT medical image based on wavelet transform algorithm

    NASA Astrophysics Data System (ADS)

    Wang, Xiaojun; Li, Xinzheng; Lai, Weidong

    2011-06-01

    Since computer tomography (CT) image has been widely applied in clinic diagnostics, while for many applications the information directly provided by CT images is incomplete corrupted by noise or instrument defect, there has great demand to further the processing methods for improving the CT image quality. Among all image features, the edge profile of clinic focus has obvious influence on accurately translating CT image. In this paper, the wavelet filtering algorithm based on modulus maximum method is put forward to extract and enhance the CT image edges. Edges in the brain lobe CT image can be outlined after wavelet transform, during which the wavelet assigned as the first order derivative of Gauss function. Further manipulation through maximum threshold checking to the modulus have been attenuated the pseudo-edges. After segmented with the original CT image, the edge structure has been distinctly enhanced, and high contrast is achieved between the brain lobe microstructure and the artificially established edges. The proposed algorithm is more efficient than the common first order differential operator, for the latter it even deteriorates the edge features. The algorithm proposed in this article can be integrated in medical image analyzing software to obtain higher accuracy for symptom interpretation.

  3. Local Wavelet Pattern: A New Feature Descriptor for Image Retrieval in Medical CT Databases.

    PubMed

    Dubey, Shiv Ram; Singh, Satish Kumar; Singh, Rajat Kumar

    2015-12-01

    A new image feature description based on the local wavelet pattern (LWP) is proposed in this paper to characterize the medical computer tomography (CT) images for content-based CT image retrieval. In the proposed work, the LWP is derived for each pixel of the CT image by utilizing the relationship of center pixel with the local neighboring information. In contrast to the local binary pattern that only considers the relationship between a center pixel and its neighboring pixels, the presented approach first utilizes the relationship among the neighboring pixels using local wavelet decomposition, and finally considers its relationship with the center pixel. A center pixel transformation scheme is introduced to match the range of center value with the range of local wavelet decomposed values. Moreover, the introduced local wavelet decomposition scheme is centrally symmetric and suitable for CT images. The novelty of this paper lies in the following two ways: 1) encoding local neighboring information with local wavelet decomposition and 2) computing LWP using local wavelet decomposed values and transformed center pixel values. We tested the performance of our method over three CT image databases in terms of the precision and recall. We also compared the proposed LWP descriptor with the other state-of-the-art local image descriptors, and the experimental results suggest that the proposed method outperforms other methods for CT image retrieval. PMID:26513789

  4. Quantitative CT for volumetric analysis of medical images: initial results for liver tumors

    NASA Astrophysics Data System (ADS)

    Behnaz, Alexander S.; Snider, James; Chibuzor, Eneh; Esposito, Giuseppe; Wilson, Emmanuel; Yaniv, Ziv; Cohen, Emil; Cleary, Kevin

    2010-03-01

    Quantitative CT for volumetric analysis of medical images is increasingly being proposed for monitoring patient response during chemotherapy trials. An integrated MATLAB GUI has been developed for an oncology trial at Georgetown University Hospital. This GUI allows for the calculation and visualization of the volume of a lesion. The GUI provides an estimate of the volume of the tumor using a semi-automatic segmentation technique. This software package features a fixed parameter adaptive filter from the ITK toolkit and a tumor segmentation algorithm to reduce inter-user variability and to facilitate rapid volume measurements. The system also displays a 3D rendering of the segmented tumor, allowing the end user to have not only a quantitative measure of the tumor volume, but a qualitative view as well. As an initial validation test, several clinical cases were hand-segmented, and then compared against the results from the tool, showing good agreement.

  5. 4D medical image computing and visualization of lung tumor mobility in spatio-temporal CT image data.

    PubMed

    Handels, Heinz; Werner, René; Schmidt, Rainer; Frenzel, Thorsten; Lu, Wei; Low, Daniel; Ehrhardt, Jan

    2007-12-01

    The development of 4D CT imaging has introduced the possibility of measuring breathing motion of tumors and inner organs. Conformal thoracic radiation therapy relies on a quantitative understanding of the position of lungs, lung tumors, and other organs during radiation delivery. Using 4D CT data sets, medical image computing and visualization methods were developed to visualize different aspects of lung and lung tumor mobility during the breathing cycle and to extract quantitative motion parameters. A non-linear registration method was applied to estimate the three-dimensional motion field and to compute 3D point trajectories. Specific visualization techniques were used to display the resulting motion field, the tumor's appearance probabilities during a breathing cycle as well as the volume covered by the moving tumor. Furthermore, trajectories of the tumor center-of-mass and organ specific landmarks were computed for the quantitative analysis of tumor and organ motion. The analysis of 4D data sets of seven patients showed that tumor mobility differs significantly between the patients depending on the individual breathing pattern and tumor location. PMID:17602865

  6. AIRS: The Medical Imaging Software for Segmentation and Registration in SPECT/CT

    NASA Astrophysics Data System (ADS)

    Widita, R.; Kurniadi, R.; Haryanto, F.; Darma, Y.; Perkasa, Y. S.; Zasneda, S. S.

    2010-06-01

    We have been successfully developed a new software, Automated Image Registration and Segmentation (AIRS), to fuse the CT and SPECT images. It is designed to solve different registration and segmentation problems that arises in tomographic data sets. AIRS is addressed to obtain anatomic information to be applied to NanoSpect system which is imaging for nano-tissues or small animals. It will be demonstrated that the information obtained by SPECT/CT is more accurate in evaluating patients/objects than that obtained from either SPECT or CT alone. The registration methods developed here are for both two-dimensional and three-dimensional registration. We used normalized mutual information (NMI) which is amenable for images produced by different modalities and having unclear boundaries between tissues. The segmentation components used in this software is region growing algorithms which have proven to be an effective approach for image segmentation. The implementations of region growing developed here are connected threshold and neighborhood connected. Our method is designed to perform with clinically acceptable speed, using accelerated techniques (multiresolution).

  7. Head CT (image)

    MedlinePlus

    CT stands for computerized tomography. In this procedure, a thin X-ray beam is rotated around the ... D image of a section through the body. CT scans are very detailed and provide excellent information ...

  8. CT scan (image)

    MedlinePlus

    CT stands for computerized tomography. In this procedure, a thin X-ray beam is rotated around the ... D image of a section through the body. CT scans are very detailed and provide excellent information ...

  9. Medical Imaging.

    ERIC Educational Resources Information Center

    Barker, M. C. J.

    1996-01-01

    Discusses four main types of medical imaging (x-ray, radionuclide, ultrasound, and magnetic resonance) and considers their relative merits. Describes important recent and possible future developments in image processing. (Author/MKR)

  10. Medical imaging.

    PubMed Central

    Kreel, L.

    1991-01-01

    There is now a wide choice of medical imaging to show both focal and diffuse pathologies in various organs. Conventional radiology with plain films, fluoroscopy and contrast medium have many advantages, being readily available with low-cost apparatus and a familiarity that almost leads to contempt. The use of plain films in chest disease and in trauma does not need emphasizing, yet there are still too many occasions when the answer obtainable from a plain radiograph has not been available. The film may have been mislaid, or the examination was not requested, or the radiograph had been misinterpreted. The converse is also quite common. Examinations are performed that add nothing to patient management, such as skull films when CT will in any case be requested or views of the internal auditory meatus and heal pad thickness in acromegaly, to quote some examples. Other issues are more complicated. Should the patient who clinically has gall-bladder disease have more than a plain film that shows gall-stones? If the answer is yes, then why request a plain film if sonography will in any case be required to 'exclude' other pathologies especially of the liver or pancreas? But then should cholecystography, CT or scintigraphy be added for confirmation? Quite clearly there will be individual circumstances to indicate further imaging after sonography but in the vast majority of patients little or no extra information will be added. Statistics on accuracy and specificity will, in the case of gall-bladder pathology, vary widely if adenomyomatosis is considered by some to be a cause of symptoms or if sonographic examinations 'after fatty meals' are performed. The arguments for or against routine contrast urography rather than sonography are similar but the possibility of contrast reactions and the need to limit ionizing radiation must be borne in mind. These diagnostic strategies are also being influenced by their cost and availability; purely pragmatic considerations are not

  11. Geometry-based vs. intensity-based medical image registration: A comparative study on 3D CT data.

    PubMed

    Savva, Antonis D; Economopoulos, Theodore L; Matsopoulos, George K

    2016-02-01

    Spatial alignment of Computed Tomography (CT) data sets is often required in numerous medical applications and it is usually achieved by applying conventional exhaustive registration techniques, which are mainly based on the intensity of the subject data sets. Those techniques consider the full range of data points composing the data, thus negatively affecting the required processing time. Alternatively, alignment can be performed using the correspondence of extracted data points from both sets. Moreover, various geometrical characteristics of those data points can be used, instead of their chromatic properties, for uniquely characterizing each point, by forming a specific geometrical descriptor. This paper presents a comparative study reviewing variations of geometry-based, descriptor-oriented registration techniques, as well as conventional, exhaustive, intensity-based methods for aligning three-dimensional (3D) CT data pairs. In this context, three general image registration frameworks were examined: a geometry-based methodology featuring three distinct geometrical descriptors, an intensity-based methodology using three different similarity metrics, as well as the commonly used Iterative Closest Point algorithm. All techniques were applied on a total of thirty 3D CT data pairs with both known and unknown initial spatial differences. After an extensive qualitative and quantitative assessment, it was concluded that the proposed geometry-based registration framework performed similarly to the examined exhaustive registration techniques. In addition, geometry-based methods dramatically improved processing time over conventional exhaustive registration. PMID:26771247

  12. A novel hybrid reconstruction algorithm for first generation incoherent scatter CT (ISCT) of large objects with potential medical imaging applications.

    PubMed

    Alpuche Aviles, Jorge E; Pistorius, Stephen; Gordon, Richard; Elbakri, Idris A

    2011-01-01

    This work presents a first generation incoherent scatter CT (ISCT) hybrid (analytic-iterative) reconstruction algorithm for accurate ρ{e}imaging of objects with clinically relevant sizes. The algorithm reconstructs quantitative images of ρ{e} within a few iterations, avoiding the challenges of optimization based reconstruction algorithms while addressing the limitations of current analytical algorithms. A 4π detector is conceptualized in order to address the issue of directional dependency and is then replaced with a ring of detectors which detect a constant fraction of the scattered photons. The ISCT algorithm corrects for the attenuation of photons using a limited number of iterations and filtered back projection (FBP) for image reconstruction. This results in a hybrid reconstruction algorithm that was tested with sinograms generated by Monte Carlo (MC) and analytical (AN) simulations. Results show that the ISCT algorithm is weakly dependent on the ρ{e} initial estimate. Simulation results show that the proposed algorithm reconstruct ρ{e} images with a mean error of -1% ± 3% for the AN model and from -6% to -8% for the MC model. Finally, the algorithm is capable of reconstructing qualitatively good images even in the presence of multiple scatter. The proposed algorithm would be suitable for in-vivo medical imaging as long as practical limitations can be addressed. PMID:21422588

  13. Medical imaging

    SciTech Connect

    Chapman, D.

    1996-09-01

    There are a number of medically related imaging programs at synchrotron facilities around the world. The most advanced of these are the dual energy transvenous coronary angiography imaging programs, which have progressed to human imaging for some years. The NSLS facility will be discussed and patient images from recent sessions from the NSLS and HASYLAB will be presented. The effort at the Photon Factory and Accumulator Ring will also be briefly covered, as well as future plans for the new facilities. Emphasis will be on the new aspects of these imaging programs; this includes imaging with a peripheral venous injection of the iodine contrast agent, imaging at three photon energies, and the potential of a hospital-based compact source. Other medical programs to be discussed, are the multiple energy computed tomography (MECT) project at the NSLS and plans for a MECT program at the ESRF. Recently, experiments performed at the NSLS to image mammography phantoms using monochromatic beam have produced very promising results. This program will be discussed as well as some new results from imaging a phantom using a thin Laue crystal analyzer after the object to eliminate scatter onto the detector. {copyright} {ital 1996 American Institute of Physics.}

  14. 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

  15. Image features for misalignment correction in medical flat-detector CT

    SciTech Connect

    Wicklein, Julia; Kunze, Holger; Kalender, Willi A.; Kyriakou, Yiannis

    2012-08-15

    Purpose: Misalignment artifacts are a serious problem in medical flat-detector computed tomography. Generally, the geometrical parameters, which are essential for reconstruction, are provided by preceding calibration routines. These procedures are time consuming and the later use of stored parameters is sensitive toward external impacts or patient movement. The method of choice in a clinical environment would be a markerless online-calibration procedure that allows flexible scan trajectories and simultaneously corrects misalignment and motion artifacts during the reconstruction process. Therefore, different image features were evaluated according to their capability of quantifying misalignment. Methods: Projections of the FORBILD head and thorax phantoms were simulated. Additionally, acquisitions of a head phantom and patient data were used for evaluation. For the reconstruction different sources and magnitudes of misalignment were introduced in the geometry description. The resulting volumes were analyzed by entropy (based on the gray-level histogram), total variation, Gabor filter texture features, Haralick co-occurrence features, and Tamura texture features. The feature results were compared to the back-projection mismatch of the disturbed geometry. Results: The evaluations demonstrate the ability of several well-established image features to classify misalignment. The authors elaborated the particular suitability of the gray-level histogram-based entropy on identifying misalignment artifacts, after applying an appropriate window level (bone window). Conclusions: Some of the proposed feature extraction algorithms show a strong correlation with the misalignment level. Especially, entropy-based methods showed very good correspondence, with the best of these being the type that uses the gray-level histogram for calculation. This makes it a suitable image feature for online-calibration.

  16. New AIRS: The medical imaging software for segmentation and registration of elastic organs in SPECT/CT

    NASA Astrophysics Data System (ADS)

    Widita, R.; Kurniadi, R.; Darma, Y.; Perkasa, Y. S.; Trianti, N.

    2012-06-01

    We have been successfully improved our software, Automated Image Registration and Segmentation (AIRS), to fuse the CT and SPECT images of elastic organs. Segmentation and registration of elastic organs presents many challenges. Many artifacts can arise in SPECT/CT scans. Also, different organs and tissues have very similar gray levels, which consign thresholding to limited utility. We have been developed a new software to solve different registration and segmentation problems that arises in tomographic data sets. It will be demonstrated that the information obtained by SPECT/CT is more accurate in evaluating patients/objects than that obtained from either SPECT or CT alone. We used multi-modality registration which is amenable for images produced by different modalities and having unclear boundaries between tissues. The segmentation components used in this software is region growing algorithms which have proven to be an effective approach for image segmentation. Our method is designed to perform with clinically acceptable speed, using accelerated techniques (multiresolution).

  17. Value of a probabilistic atlas in medical image segmentation regarding non-rigid registration of abdominal CT scans

    NASA Astrophysics Data System (ADS)

    Park, Hyunjin; Meyer, Charles R.

    2012-10-01

    A probabilistic atlas provides important information to help segmentation and registration applications in medical image analysis. We construct a probabilistic atlas by picking a target geometry and mapping other training scans onto that target and then summing the results into one probabilistic atlas. By choosing an atlas space close to the desired target, we construct an atlas that represents the population well. Image registration used to map one image geometry onto another is a primary task in atlas building. One of the main parameters of registration is the choice of degrees of freedom (DOFs) of the geometric transform. Herein, we measure the effect of the registration's DOFs on the segmentation performance of the resulting probabilistic atlas. Twenty-three normal abdominal CT scans were used, and four organs (liver, spinal cord, left and right kidneys) were segmented for each scan. A well-known manifold learning method, ISOMAP, was used to find the best target space to build an atlas. In summary, segmentation performance was high for high DOF registrations regardless of the chosen target space, while segmentation performance was lowered for low DOF registrations if a target space was far from the best target space. At the 0.05 level of statistical significance, there were no significant differences at high DOF registrations while there were significant differences at low DOF registrations when choosing different targets.

  18. Clinical utility of three-dimensional SPECT/CT imaging as a guide for the resection of medication-related osteonecrosis of the jaw.

    PubMed

    Miyashita, H; Shiba, H; Kawana, H; Nakahara, T

    2015-09-01

    In recent years, proactive surgical treatment has been reported to be effective for medication-related osteonecrosis of the jaw (MRONJ). However, an uncertain resection entails the risk of recurrence, whereas an extensive surgical procedure may lead to a marked reduction in quality of life as a result of reduced masticatory function and poor cosmesis. Therefore, radiological assessment can be helpful to accurately localize MRONJ before surgery. The integrated single-photon emission computed tomography and computed tomography system (SPECT/CT) allows oral and maxillofacial surgeons to identify an area of MRONJ, especially when three-dimensional (3D) SPECT and CT fusion images are offered. A patient for whom 3D SPECT and CT image fusion (as developed in the radiology department of the study institution) contributed to determining the extent of the lesion, thereby leading to a favourable patient prognosis, is reported herein. There was exact correlation between the histological and radiological results. PMID:26008732

  19. PET/CT imaging artifacts.

    PubMed

    Sureshbabu, Waheeda; Mawlawi, Osama

    2005-09-01

    The purpose of this paper is to introduce the principles of PET/CT imaging and describe the artifacts associated with it. PET/CT is a new imaging modality that integrates functional (PET) and structural (CT) information into a single scanning session, allowing excellent fusion of the PET and CT images and thus improving lesion localization and interpretation accuracy. Moreover, the CT data can also be used for attenuation correction, ultimately leading to high patient throughput. These combined advantages have rendered PET/CT a preferred imaging modality over dedicated PET. Although PET/CT imaging offers many advantages, this dual-modality imaging also poses some challenges. CT-based attenuation correction can induce artifacts and quantitative errors that can affect the PET emission images. For instance, the use of contrast medium and the presence of metallic implants can be associated with focal radiotracer uptake. Furthermore, the patient's breathing can introduce mismatches between the CT attenuation map and the PET emission data, and the discrepancy between the CT and PET fields of view can lead to truncation artifacts. After reading this article, the technologist should be able to describe the principles of PET/CT imaging, identify at least 3 types of image artifacts, and describe the differences between PET/CT artifacts of different causes: metallic implants, respiratory motion, contrast medium, and truncation. PMID:16145223

  20. A novel concept for CT with fixed anodes (FACT): Medical imaging based on the feasibility of thermal load capacity.

    PubMed

    Kellermeier, Markus; Bert, Christoph; Müller, Reinhold G

    2015-07-01

    Focussing primarily on thermal load capacity, we describe the performance of a novel fixed anode CT (FACT) compared with a 100 kW reference CT. Being a fixed system, FACT has no focal spot blurring of the X-ray source during projection. Monte Carlo and finite element methods were used to determine the fluence proportional to thermal capacity. Studies of repeated short-time exposures showed that FACT could operate in pulsed mode for an unlimited period. A virtual model for FACT was constructed to analyse various temporal sequences for the X-ray source ring, representing a circular array of 1160 fixed anodes in the gantry. Assuming similar detector properties at a very small integration time, image quality was investigated using an image reconstruction library. Our model showed that approximately 60 gantry rounds per second, i.e. 60 sequential targetings of the 1160 anodes per second, were required to achieve a performance level equivalent to that of the reference CT (relative performance, RP = 1) at equivalent image quality. The optimal projection duration in each direction was about 10 μs. With a beam pause of 1 μs between projections, 78.4 gantry rounds per second with consecutive source activity were thermally possible at a given thermal focal spot. The settings allowed for a 1.3-fold (RP = 1.3) shorter scan time than conventional CT while maintaining radiation exposure and image quality. Based on the high number of rounds, FACT supports a high image frame rate at low doses, which would be beneficial in a wide range of diagnostic and technical applications. PMID:25890700

  1. Improvements in medical CT image reconstruction accuracy in the presence of metal objects by using x-rays up to 1 MeV

    NASA Astrophysics Data System (ADS)

    Clayton, James; Virshup, Gary; Yang, Ming; Mohan, Radhe; Dong, Lei

    2009-03-01

    The use of flat panels based on amorphous silicon technology (a-Si) for digital radiography has been accepted by the medical community as having advantages over film-based systems. Radiation treatment planning employs computed tomographic (CT) data sets and projection images to delineate tumor targets and normal structures that are to be spared from radiation treatment. The accuracy of CT numbers is crucial for radiotherapy dose calculations in general but is even more important for charged particle therapy. Conventional CT scanners operating at kilovoltage X-ray energies typically exhibit significant image reconstruction artifacts in the presence of metal implants in human body. We demonstrate a significant improvement in metal artifact reductions and electron density measurements using an amorphous silicon a-Si imager obtained with an X-ray source that can operate at energies up to 1 MeV. The data collected with the higher energy system will be compared and contrasted to CT results obtained at standard kilovoltage energies.

  2. Scintillator requirements for medical imaging

    SciTech Connect

    Moses, William W.

    1999-09-01

    Scintillating materials are used in a variety of medical imaging devices. This paper presents a description of four medical imaging modalities that make extensive use of scintillators: planar x-ray imaging, x-ray computed tomography (x-ray CT), SPECT (single photon emission computed tomography) and PET (positron emission tomography). The discussion concentrates on a description of the underlying physical principles by which the four modalities operate. The scintillator requirements for these systems are enumerated and the compromises that are made in order to maximize imaging performance utilizing existing scintillating materials are discussed, as is the potential for improving imaging performance by improving scintillator properties.

  3. Medical image analysis methods in MR/CT-imaged acute-subacute ischemic stroke lesion: Segmentation, prediction and insights into dynamic evolution simulation models. A critical appraisal☆

    PubMed Central

    Rekik, Islem; Allassonnière, Stéphanie; Carpenter, Trevor K.; Wardlaw, Joanna M.

    2012-01-01

    Over the last 15 years, basic thresholding techniques in combination with standard statistical correlation-based data analysis tools have been widely used to investigate different aspects of evolution of acute or subacute to late stage ischemic stroke in both human and animal data. Yet, a wave of biology-dependent and imaging-dependent issues is still untackled pointing towards the key question: “how does an ischemic stroke evolve?” Paving the way for potential answers to this question, both magnetic resonance (MRI) and CT (computed tomography) images have been used to visualize the lesion extent, either with or without spatial distinction between dead and salvageable tissue. Combining diffusion and perfusion imaging modalities may provide the possibility of predicting further tissue recovery or eventual necrosis. Going beyond these basic thresholding techniques, in this critical appraisal, we explore different semi-automatic or fully automatic 2D/3D medical image analysis methods and mathematical models applied to human, animal (rats/rodents) and/or synthetic ischemic stroke to tackle one of the following three problems: (1) segmentation of infarcted and/or salvageable (also called penumbral) tissue, (2) prediction of final ischemic tissue fate (death or recovery) and (3) dynamic simulation of the lesion core and/or penumbra evolution. To highlight the key features in the reviewed segmentation and prediction methods, we propose a common categorization pattern. We also emphasize some key aspects of the methods such as the imaging modalities required to build and test the presented approach, the number of patients/animals or synthetic samples, the use of external user interaction and the methods of assessment (clinical or imaging-based). Furthermore, we investigate how any key difficulties, posed by the evolution of stroke such as swelling or reperfusion, were detected (or not) by each method. In the absence of any imaging-based macroscopic dynamic model

  4. Medical Imaging.

    ERIC Educational Resources Information Center

    Jaffe, C. Carl

    1982-01-01

    Describes principle imaging techniques, their applications, and their limitations in terms of diagnostic capability and possible adverse biological effects. Techniques include film radiography, computed tomography, nuclear medicine, positron emission tomography (PET), ultrasonography, nuclear magnetic resonance, and digital radiography. PET has…

  5. Flow behaviour of supercritical CO2 and brine in Berea sandstone during drainage and imbibition revealed by medical X-ray CT images

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Nishizawa, Osamu; Kiyama, Tamotsu; Chiyonobu, Shun; Xue, Ziqiu

    2014-06-01

    We injected Berea sandstone with supercritical CO2 and imaged the results with a medical X-ray computed tomography (CT) scanner. The images were acquired by injecting CO2 into a core of brine-saturated sandstone (drainage), and additional images were acquired during reinjection of brine (imbibition) after drainage. We then analysed the temporal variations of CO2 saturation maps obtained from the CT images. The experiments were performed under a confining pressure of 12 MPa, a pore pressure of 10 MPa and a temperature of 40 °C. Porosity and CO2 saturation were calculated for each image voxel of the rock on the basis of the Hounsfield unit values (CT numbers) measured at three states of saturation: dry, full brine saturation and full CO2 saturation. The saturation maps indicated that the distributions of CO2 and brine were controlled by the sub-core-scale heterogeneities which consisted of a laminated structure (bedding) with high- and low-porosity layers. During drainage, CO2 preferentially flowed through the high-porosity layers where most of the CO2 was entrapped during low flow-rate imbibition. The entrapped CO2 was flushed out when high flow-rate imbibition commenced. Plots of the voxel's CT number against porosity revealed the relationship between fluid replacement and porosity. By reference to the CT numbers at the full brine-saturated stage, differential CT numbers were classified into three bins corresponding to voxel porosity: high, medium and low porosity. Distributions of the differential CT number for the three porosity bins were bimodal and in order with respect to the porosity bins during both drainage and imbibitions; however, the order differed between the two stages. This difference suggested that different replacement mechanisms operated for the two processes. Spatial autocorrelation of CO2 saturation maps on sections perpendicular to the flow direction revealed remarkable changes during passage of the replacement fronts during both drainage and

  6. Imaging medical imaging

    NASA Astrophysics Data System (ADS)

    Journeau, P.

    2015-03-01

    This paper presents progress on imaging the research field of Imaging Informatics, mapped as the clustering of its communities together with their main results by applying a process to produce a dynamical image of the interactions between their results and their common object(s) of research. The basic side draws from a fundamental research on the concept of dimensions and projective space spanning several streams of research about three-dimensional perceptivity and re-cognition and on their relation and reduction to spatial dimensionality. The application results in an N-dimensional mapping in Bio-Medical Imaging, with dimensions such as inflammatory activity, MRI acquisition sequencing, spatial resolution (voxel size), spatiotemporal dimension inferred, toxicity, depth penetration, sensitivity, temporal resolution, wave length, imaging duration, etc. Each field is represented through the projection of papers' and projects' `discriminating' quantitative results onto the specific N-dimensional hypercube of relevant measurement axes, such as listed above and before reduction. Past published differentiating results are represented as red stars, achieved unpublished results as purple spots and projects at diverse progress advancement levels as blue pie slices. The goal of the mapping is to show the dynamics of the trajectories of the field in its own experimental frame and their direction, speed and other characteristics. We conclude with an invitation to participate and show a sample mapping of the dynamics of the community and a tentative predictive model from community contribution.

  7. RONI Based Secured and Authenticated Indexing of Lung CT Images

    PubMed Central

    Jasmine Selvakumari Jeya, I.; Suganthi, J.

    2015-01-01

    Medical images need to be transmitted with the patient's information without altering the image data. The present paper discusses secured indexing of lung CT image (SILI) which is a secured way of indexing the lung CT images with the patient information. Authentication is provided using the sender's logo information and the secret key is used for embedding the watermark into the host image. Watermark is embedded into the region of Noninterest (RONI) of the lung CT image. RONI is identified by segmenting the lung tissue from the CT scan image. The experimental results show that the proposed approach is robust against unauthorized access, noise, blurring, and intensity based attacks. PMID:26078782

  8. RONI Based Secured and Authenticated Indexing of Lung CT Images.

    PubMed

    Jasmine Selvakumari Jeya, I; Suganthi, J

    2015-01-01

    Medical images need to be transmitted with the patient's information without altering the image data. The present paper discusses secured indexing of lung CT image (SILI) which is a secured way of indexing the lung CT images with the patient information. Authentication is provided using the sender's logo information and the secret key is used for embedding the watermark into the host image. Watermark is embedded into the region of Noninterest (RONI) of the lung CT image. RONI is identified by segmenting the lung tissue from the CT scan image. The experimental results show that the proposed approach is robust against unauthorized access, noise, blurring, and intensity based attacks. PMID:26078782

  9. NETL CT Imaging Facility

    ScienceCinema

    None

    2014-05-21

    NETL's CT Scanner laboratory is equipped with three CT scanners and a mobile core logging unit that work together to provide characteristic geologic and geophysical information at different scales, non-destructively.

  10. NETL CT Imaging Facility

    SciTech Connect

    2013-09-04

    NETL's CT Scanner laboratory is equipped with three CT scanners and a mobile core logging unit that work together to provide characteristic geologic and geophysical information at different scales, non-destructively.

  11. Investigating existing medical CT segmentation techniques within automated baggage and package inspection

    NASA Astrophysics Data System (ADS)

    Megherbi, Najla; Breckon, Toby P.; Flitton, Greg T.

    2013-10-01

    3D Computed Tomography (CT) image segmentation is already well established tool in medical research and in routine daily clinical practice. However, such techniques have not been used in the context of 3D CT image segmentation for baggage and package security screening using CT imagery. CT systems are increasingly used in airports for security baggage examination. We propose in this contribution an investigation of the current 3D CT medical image segmentation methods for use in this new domain. Experimental results of 3D segmentation on real CT baggage security imagery using a range of techniques are presented and discussed.

  12. CT image retrieval using dual tree complex wavelet packet transform

    NASA Astrophysics Data System (ADS)

    Kokare, Manesh

    2010-02-01

    In this paper, novel method based on Dual Tree Complex Wavelet Packet Transform (DT-CWPT) to analyze texture of Computer Tomography (CT) images and extract the corresponding feature vectors for content based medical image retrieval is proposed. This is mainly because of DT-CWPT characterizes textural property of CT images in better way. The feature vectors of CT images are extracted by measuring energy and standard deviation of DT-CWPT subband. These features are used to facilitate content based medical image retrieval (CBMIR).The proposed method outperforms than existing available methods.

  13. Body-wide anatomy recognition in PET/CT images

    NASA Astrophysics Data System (ADS)

    Wang, Huiqian; Udupa, Jayaram K.; Odhner, Dewey; Tong, Yubing; Zhao, Liming; Torigian, Drew A.

    2015-03-01

    With the rapid growth of positron emission tomography/computed tomography (PET/CT)-based medical applications, body-wide anatomy recognition on whole-body PET/CT images becomes crucial for quantifying body-wide disease burden. This, however, is a challenging problem and seldom studied due to unclear anatomy reference frame and low spatial resolution of PET images as well as low contrast and spatial resolution of the associated low-dose CT images. We previously developed an automatic anatomy recognition (AAR) system [15] whose applicability was demonstrated on diagnostic computed tomography (CT) and magnetic resonance (MR) images in different body regions on 35 objects. The aim of the present work is to investigate strategies for adapting the previous AAR system to low-dose CT and PET images toward automated body-wide disease quantification. Our adaptation of the previous AAR methodology to PET/CT images in this paper focuses on 16 objects in three body regions - thorax, abdomen, and pelvis - and consists of the following steps: collecting whole-body PET/CT images from existing patient image databases, delineating all objects in these images, modifying the previous hierarchical models built from diagnostic CT images to account for differences in appearance in low-dose CT and PET images, automatically locating objects in these images following object hierarchy, and evaluating performance. Our preliminary evaluations indicate that the performance of the AAR approach on low-dose CT images achieves object localization accuracy within about 2 voxels, which is comparable to the accuracies achieved on diagnostic contrast-enhanced CT images. Object recognition on low-dose CT images from PET/CT examinations without requiring diagnostic contrast-enhanced CT seems feasible.

  14. Medical Imaging System

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The MD Image System, a true-color image processing system that serves as a diagnostic aid and tool for storage and distribution of images, was developed by Medical Image Management Systems, Huntsville, AL, as a "spinoff from a spinoff." The original spinoff, Geostar 8800, developed by Crystal Image Technologies, Huntsville, incorporates advanced UNIX versions of ELAS (developed by NASA's Earth Resources Laboratory for analysis of Landsat images) for general purpose image processing. The MD Image System is an application of this technology to a medical system that aids in the diagnosis of cancer, and can accept, store and analyze images from other sources such as Magnetic Resonance Imaging.

  15. Medical image file formats.

    PubMed

    Larobina, Michele; Murino, Loredana

    2014-04-01

    Image file format is often a confusing aspect for someone wishing to process medical images. This article presents a demystifying overview of the major file formats currently used in medical imaging: Analyze, Neuroimaging Informatics Technology Initiative (Nifti), Minc, and Digital Imaging and Communications in Medicine (Dicom). Concepts common to all file formats, such as pixel depth, photometric interpretation, metadata, and pixel data, are first presented. Then, the characteristics and strengths of the various formats are discussed. The review concludes with some predictive considerations about the future trends in medical image file formats. PMID:24338090

  16. CT number variations in micro CT imaging systems

    NASA Astrophysics Data System (ADS)

    Tu, Shu-Ju; Hsieh, Hui-Ling; Chao, Tsi-Chian

    2008-03-01

    CT numbers can be directly computed from the linear attenuation coefficients in the reconstructed CT images and are correlated to the electron densities of the chemical elements with specific atomic numbers. However, the computed CT numbers can be varied when different imaging parameters are used. Phantoms composed of clinically relevant and tissue-equivalent materials (lung, bone, muscle, and adipose) were scanned with a commercial circular-scanning micro CT imager. This imaging system is composed with a micro-focused x-ray tube and charged-coupled device (CCD) camera as the detector. The mean CT numbers and the corresponding standard deviations in terms of Hounsfield units were then computed from a pre-defined region of interest located within the reconstructed volumetric images. The variations of CT number were then identified from a series of imaging parameters. Those parameters include imaging acquisition modes (e.g., the metal filter used in the x-ray tube), reconstruction methods (e.g., Feldkamp and iterative algorithm), and post-image processing techniques (e.g., ring artifact, beam-hardening artifact, and smoothing processing). These variations of CT numbers are useful and important in tissue characterization, quantitative bone structure analysis, bone marrow density evaluation, and Monte Carlo dose calculations for the pilot small animal study when micro CT imaging systems are employed. Also these variations can be used as the quantification for the performance of the micro CT imaging systems.

  17. Stereoscopic medical imaging collaboration system

    NASA Astrophysics Data System (ADS)

    Okuyama, Fumio; Hirano, Takenori; Nakabayasi, Yuusuke; Minoura, Hirohito; Tsuruoka, Shinji

    2007-02-01

    The computerization of the clinical record and the realization of the multimedia have brought improvement of the medical service in medical facilities. It is very important for the patients to obtain comprehensible informed consent. Therefore, the doctor should plainly explain the purpose and the content of the diagnoses and treatments for the patient. We propose and design a Telemedicine Imaging Collaboration System which presents a three dimensional medical image as X-ray CT, MRI with stereoscopic image by using virtual common information space and operating the image from a remote location. This system is composed of two personal computers, two 15 inches stereoscopic parallax barrier type LCD display (LL-151D, Sharp), one 1Gbps router and 1000base LAN cables. The software is composed of a DICOM format data transfer program, an operation program of the images, the communication program between two personal computers and a real time rendering program. Two identical images of 512×768 pixcels are displayed on two stereoscopic LCD display, and both images show an expansion, reduction by mouse operation. This system can offer a comprehensible three-dimensional image of the diseased part. Therefore, the doctor and the patient can easily understand it, depending on their needs.

  18. [Medical image enhancement: Sharpening].

    PubMed

    Kats, L; Vered, M

    2015-04-01

    Most digital imaging systems provide opportunities for image enhancement operations. These are applied to improve the original image and to make the image more appealing visually. One possible means of enhancing digital radiographic image is sharpening. The purpose of sharpening filters is to improve image quality by removing noise or edge enhancement. Sharpening filters may make the radiographic images subjectively more appealing. But during this process, important radiographic features may disappear while artifacts that simulate pathological process might be generated. Therefore, it is of utmost importance for dentists to be familiar with and aware of the use of image enhancement operations, provided by medical digital imaging programs. PMID:26255429

  19. To Scan or not to Scan: Consideration of Medical Benefit in the Justification of CT Scanning.

    PubMed

    McCollough, Cynthia H

    2016-03-01

    While there are ongoing debates with regard to the level of risk, if any, associated with medical imaging, the benefits from medical imaging exams are well documented. This forum article looks at outcome-based medical studies and guidance from expert panels in an effort to bring the benefits of medical imaging, specifically CT imaging, into focus. The position is taken that imaging, medical, and safety communities must not continue to discuss small hypothetical risks from ionizing radiation without emphasizing the large well-documented benefits from medical imaging exams that use ionizing radiation. PMID:26808885

  20. Medical ultrasound imaging.

    PubMed

    Jensen, Jørgen Arendt

    2007-01-01

    The paper gives an introduction to current medical ultrasound imaging systems. The basics of anatomic and blood flow imaging are described. The properties of medical ultrasound and its focusing are described, and the various methods for two- and three-dimensional imaging of the human anatomy are shown. Systems using both linear and non-linear propagation of ultrasound are described. The blood velocity can also be non-invasively visualized using ultrasound and the basic signal processing for doing this is introduced. Examples for spectral velocity estimation, color flow imaging and the new vector velocity images are presented. PMID:17092547

  1. Medical imaging systems

    DOEpatents

    Frangioni, John V

    2013-06-25

    A medical imaging system provides simultaneous rendering of visible light and diagnostic or functional images. The system may be portable, and may include adapters for connecting various light sources and cameras in open surgical environments or laparascopic or endoscopic environments. A user interface provides control over the functionality of the integrated imaging system. In one embodiment, the system provides a tool for surgical pathology.

  2. CT Imaging: Basics and New Trends

    NASA Astrophysics Data System (ADS)

    Peyrin, Françoise; Engelke, Klaus

    This chapter presents the principle of X-ray CT and its evolution during the last 40 years. The first section describes the physical basis of X-ray CT, tomographic image reconstruction algorithms, and the source of artifacts in X-ray CT images. The second section is devoted to the evolution of CT technology from the first translation-rotation systems to multi-slice spiral CTs currently used today. The next section addresses specific developments of CT technology and applications, like perfusion CT, quantitative CT, and spectral CT. The fourth section introduces the problem of radiation exposure delivered to the patient and its evaluation. Finally the last section addresses the development in micro- and even nano-CT which is a rapidly evolving area in preclinical imaging and biology.

  3. [Medical imaging: its medical economics and recent situation in Japan.].

    PubMed

    Imai, Keiko

    2006-01-01

    Two fields of radiology, medical imaging and radiation therapy, are coded separately in medical fee system, and the health care statistics of 2003 shows that expenditure on the former was 5.2% of the whole medical cost and the latter 0.28%. Introduction of DPC, an abbreviation of Diagnostic Procedure Combination, was carried out in 2003, which was an essential reform of medical fee payment system that have been managed on fee-for-service base throughout, and 22% of beds for acute patients care are under the control of DPC payment in 2006. As medical imaging procedures are basically classified in inclusive payment in DPC system, their accurate statistics cannot be figured out because of the lack of description of individual procedures in DPC bills. Policy-making of medical economics will suffer a great loss from the deficiency of detailed data in published statistics. Important role in clinical diagnoses of CT and MR results an increase of fee paid for them up to more than half of total expenditure on medical imaging. So, dominant reduction of examination fee has been done for MR imaging, especially in 2002, to reduce the total cost of medical imaging. Follows could be featured as major topics of medical imaging in health insurance system, (a) fee is newly assigned for electronic handling of CT-and-MR images, and nuclear medicine, and (b) there is still a mismatch between actual payment and quality of medical facilities. As matters related to medical imaging, the followings should be stressed; (a) numbers of CT and MR units per population are dominantly high among OECD countries, but, those controlled by qualified radiologists are at the average level of those countries, (b) there is a big difference of MR examination quality among medical facilities, and (c) 76% of newly-installed high-end MR units are supplied by foreign industries. Hopefully, there will be an increase in the concern to medical fee payment system and health care cost because they possibly

  4. Imaging and Analytics: The changing face of Medical Imaging

    NASA Astrophysics Data System (ADS)

    Foo, Thomas

    There have been significant technological advances in imaging capability over the past 40 years. Medical imaging capabilities have developed rapidly, along with technology development in computational processing speed and miniaturization. Moving to all-digital, the number of images that are acquired in a routine clinical examination has increased dramatically from under 50 images in the early days of CT and MRI to more than 500-1000 images today. The staggering number of images that are routinely acquired poses significant challenges for clinicians to interpret the data and to correctly identify the clinical problem. Although the time provided to render a clinical finding has not substantially changed, the amount of data available for interpretation has grown exponentially. In addition, the image quality (spatial resolution) and information content (physiologically-dependent image contrast) has also increased significantly with advances in medical imaging technology. On its current trajectory, medical imaging in the traditional sense is unsustainable. To assist in filtering and extracting the most relevant data elements from medical imaging, image analytics will have a much larger role. Automated image segmentation, generation of parametric image maps, and clinical decision support tools will be needed and developed apace to allow the clinician to manage, extract and utilize only the information that will help improve diagnostic accuracy and sensitivity. As medical imaging devices continue to improve in spatial resolution, functional and anatomical information content, image/data analytics will be more ubiquitous and integral to medical imaging capability.

  5. Intracranial vascular malformations: MR and CT imaging

    SciTech Connect

    Kucharczyk, W.; Lemme-Pleghos, L.; Uske, A.; Brant-Zawadzki, M.; Dooms, G.; Norman, D.

    1985-08-01

    Twenty-four patients with 29 cerebrovascular malformations were evaluated with a combination of computed tomography (CT), angiography, and magnetic resonance (MR) imaging. Characteristics of the malformations on MR images were reviewed retrospectively, and a comparative evaluation of MR and CT images was made. Of 14 angiographically evident malformations, 13 intra-axial lesions were detected on both CT and MR images, and one dural malformation gave false-negative results on both modalities. The appearance of parenchymal lesions on MR images closely mirrored characteristic CT findings. Angiographically evident malformations have a highly characteristic appearance on MR images. MR may be more sensitive than CT in the detection of small hemorrhagic foci associated with cryptic arteriovenous malformations and may add specificity in the diagnosis of occult malformations in some cases, but MR is less sensitive than CT for the detection of small calcified malformations.

  6. Segmentation-based CT image compression

    NASA Astrophysics Data System (ADS)

    Thammineni, Arunoday; Mukhopadhyay, Sudipta; Kamath, Vidya

    2004-04-01

    The existing image compression standards like JPEG and JPEG 2000, compress the whole image as a single frame. This makes the system simple but inefficient. The problem is acute for applications where lossless compression is mandatory viz. medical image compression. If the spatial characteristics of the image are considered, it can give rise to a more efficient coding scheme. For example, CT reconstructed images have uniform background outside the field of view (FOV). Even the portion within the FOV can be divided as anatomically relevant and irrelevant parts. They have distinctly different statistics. Hence coding them separately will result in more efficient compression. Segmentation is done based on thresholding and shape information is stored using 8-connected differential chain code. Simple 1-D DPCM is used as the prediction scheme. The experiments show that the 1st order entropies of images fall by more than 11% when each segment is coded separately. For simplicity and speed of decoding Huffman code is chosen for entropy coding. Segment based coding will have an overhead of one table per segment but the overhead is minimal. Lossless compression of image based on segmentation resulted in reduction of bit rate by 7%-9% compared to lossless compression of whole image as a single frame by the same prediction coder. Segmentation based scheme also has the advantage of natural ROI based progressive decoding. If it is allowed to delete the diagnostically irrelevant portions, the bit budget can go down as much as 40%. This concept can be extended to other modalities.

  7. Wavelet compression efficiency investigation for medical images

    NASA Astrophysics Data System (ADS)

    Moryc, Marcin; Dziech, Wiera

    2006-03-01

    Medical images are acquired or stored digitally. These images can be very large in size and number, and compression can increase the speed of transmission and reduce the cost of storage. In the paper analysis of medical images' approximation using the transform method based on wavelet functions is investigated. The tested clinical images are taken from multiple anatomical regions and modalities (Computer Tomography CT, Magnetic Resonance MR, Ultrasound, Mammography and X-Ray images). To compress medical images, the threshold criterion has been applied. The mean square error (MSE) is used as a measure of approximation quality. Plots of the MSE versus compression percentage and approximated images are included for comparison of approximation efficiency.

  8. Image quality assessment for CT used on small animals

    NASA Astrophysics Data System (ADS)

    Cisneros, Isabela Paredes; Agulles-Pedrós, Luis

    2016-07-01

    Image acquisition on a CT scanner is nowadays necessary in almost any kind of medical study. Its purpose, to produce anatomical images with the best achievable quality, implies the highest diagnostic radiation exposure to patients. Image quality can be measured quantitatively based on parameters such as noise, uniformity and resolution. This measure allows the determination of optimal parameters of operation for the scanner in order to get the best diagnostic image. A human Phillips CT scanner is the first one minded for veterinary-use exclusively in Colombia. The aim of this study was to measure the CT image quality parameters using an acrylic phantom and then, using the computational tool MatLab, determine these parameters as a function of current value and window of visualization, in order to reduce dose delivery by keeping the appropriate image quality.

  9. Medical Images Remote Consultation

    NASA Astrophysics Data System (ADS)

    Ferraris, Maurizio; Frixione, Paolo; Squarcia, Sandro

    Teleconsultation of digital images among different medical centers is now a reality. The problem to be solved is how to interconnect all the clinical diagnostic devices in a hospital in order to allow physicians and health physicists, working in different places, to discuss on interesting clinical cases visualizing the same diagnostic images at the same time. Applying World Wide Web technologies, the proposed system can be easily used by people with no specific computer knowledge providing a verbose help to guide the user through the right steps of execution. Diagnostic images are retrieved from a relational database or from a standard DICOM-PACS through the DICOM-WWW gateway allowing connection of the usual Web browsers to DICOM applications via the HTTP protocol. The system, which is proposed for radiotherapy implementation, where radiographies play a fundamental role, can be easily converted to different field of medical applications where a remote access to secure data are compulsory.

  10. Mobile medical image retrieval

    NASA Astrophysics Data System (ADS)

    Duc, Samuel; Depeursinge, Adrien; Eggel, Ivan; Müller, Henning

    2011-03-01

    Images are an integral part of medical practice for diagnosis, treatment planning and teaching. Image retrieval has gained in importance mainly as a research domain over the past 20 years. Both textual and visual retrieval of images are essential. In the process of mobile devices becoming reliable and having a functionality equaling that of formerly desktop clients, mobile computing has gained ground and many applications have been explored. This creates a new field of mobile information search & access and in this context images can play an important role as they often allow understanding complex scenarios much quicker and easier than free text. Mobile information retrieval in general has skyrocketed over the past year with many new applications and tools being developed and all sorts of interfaces being adapted to mobile clients. This article describes constraints of an information retrieval system including visual and textual information retrieval from the medical literature of BioMedCentral and of the RSNA journals Radiology and Radiographics. Solutions for mobile data access with an example on an iPhone in a web-based environment are presented as iPhones are frequently used and the operating system is bound to become the most frequent smartphone operating system in 2011. A web-based scenario was chosen to allow for a use by other smart phone platforms such as Android as well. Constraints of small screens and navigation with touch screens are taken into account in the development of the application. A hybrid choice had to be taken to allow for taking pictures with the cell phone camera and upload them for visual similarity search as most producers of smart phones block this functionality to web applications. Mobile information access and in particular access to images can be surprisingly efficient and effective on smaller screens. Images can be read on screen much faster and relevance of documents can be identified quickly through the use of images contained in

  11. Improved Interactive Medical-Imaging System

    NASA Technical Reports Server (NTRS)

    Ross, Muriel D.; Twombly, Ian A.; Senger, Steven

    2003-01-01

    An improved computational-simulation system for interactive medical imaging has been invented. The system displays high-resolution, three-dimensional-appearing images of anatomical objects based on data acquired by such techniques as computed tomography (CT) and magnetic-resonance imaging (MRI). The system enables users to manipulate the data to obtain a variety of views for example, to display cross sections in specified planes or to rotate images about specified axes. Relative to prior such systems, this system offers enhanced capabilities for synthesizing images of surgical cuts and for collaboration by users at multiple, remote computing sites.

  12. Medical CT image reconstruction accuracy in the presence of metal objects using x-rays up to 1 MeV with x-ray targets of beryllium, carbon, aluminum, copper, and tungsten

    NASA Astrophysics Data System (ADS)

    Clayton, James; Ganguly, Arundhuti; Virshup, Gary

    2012-04-01

    Flat panels imagers based on amorphous silicon technology (a-Si) for digital radiography have been accepted by the medical community as having several advantages over film-based systems. Radiotherapy treatment planning systems employ computed tomographic (CT) data sets and projection images to delineate tumor targets and normal structures that are to be spared from radiation treatment. The accuracy of CT numbers is crucial for radiotherapy dose calculations. Conventional CT scanners operating at kilovoltage X-ray energies typically exhibit significant image reconstruction artifacts in the presence of metal implants in human body. Megavoltage X-ray energies have problems maintaining contrast sensitivity for the same dose as kV X-ray systems. We intend to demonstrate significant improvement in metal artifact reductions and electron density measurements using an amorphous silicon a-Si imager obtained with an X-ray source that can operate at energies up to 1 MeV. We will investigate the ability to maintain contrast sensitivity at this higher X-ray energy by using targets with lower atomic numbers and appropriate amounts of Xray filtration than are typically used as X-ray production targets and filters.

  13. Medical imaging systems

    SciTech Connect

    Frangioni, John V.

    2012-07-24

    A medical imaging system provides simultaneous rendering of visible light and fluorescent images. The system may employ dyes in a small-molecule form that remains in a subject's blood stream for several minutes, allowing real-time imaging of the subject's circulatory system superimposed upon a conventional, visible light image of the subject. The system may also employ dyes or other fluorescent substances associated with antibodies, antibody fragments, or ligands that accumulate within a region of diagnostic significance. In one embodiment, the system provides an excitation light source to excite the fluorescent substance and a visible light source for general illumination within the same optical guide that is used to capture images. In another embodiment, the system is configured for use in open surgical procedures by providing an operating area that is closed to ambient light. More broadly, the systems described herein may be used in imaging applications where a visible light image may be usefully supplemented by an image formed from fluorescent emissions from a fluorescent substance that marks areas of functional interest.

  14. 3D motion artifact compenstation in CT image with depth camera

    NASA Astrophysics Data System (ADS)

    Ko, Youngjun; Baek, Jongduk; Shim, Hyunjung

    2015-02-01

    Computed tomography (CT) is a medical imaging technology that projects computer-processed X-rays to acquire tomographic images or the slices of specific organ of body. A motion artifact caused by patient motion is a common problem in CT system and may introduce undesirable artifacts in CT images. This paper analyzes the critical problems in motion artifacts and proposes a new CT system for motion artifact compensation. We employ depth cameras to capture the patient motion and account it for the CT image reconstruction. In this way, we achieve the significant improvement in motion artifact compensation, which is not possible by previous techniques.

  15. Wavelets in medical imaging

    SciTech Connect

    Zahra, Noor e; Sevindir, Huliya A.; Aslan, Zafar; Siddiqi, A. H.

    2012-07-17

    The aim of this study is to provide emerging applications of wavelet methods to medical signals and images, such as electrocardiogram, electroencephalogram, functional magnetic resonance imaging, computer tomography, X-ray and mammography. Interpretation of these signals and images are quite important. Nowadays wavelet methods have a significant impact on the science of medical imaging and the diagnosis of disease and screening protocols. Based on our initial investigations, future directions include neurosurgical planning and improved assessment of risk for individual patients, improved assessment and strategies for the treatment of chronic pain, improved seizure localization, and improved understanding of the physiology of neurological disorders. We look ahead to these and other emerging applications as the benefits of this technology become incorporated into current and future patient care. In this chapter by applying Fourier transform and wavelet transform, analysis and denoising of one of the important biomedical signals like EEG is carried out. The presence of rhythm, template matching, and correlation is discussed by various method. Energy of EEG signal is used to detect seizure in an epileptic patient. We have also performed denoising of EEG signals by SWT.

  16. Wavelets in medical imaging

    NASA Astrophysics Data System (ADS)

    Zahra, Noor e.; Sevindir, Huliya A.; Aslan, Zafar; Siddiqi, A. H.

    2012-07-01

    The aim of this study is to provide emerging applications of wavelet methods to medical signals and images, such as electrocardiogram, electroencephalogram, functional magnetic resonance imaging, computer tomography, X-ray and mammography. Interpretation of these signals and images are quite important. Nowadays wavelet methods have a significant impact on the science of medical imaging and the diagnosis of disease and screening protocols. Based on our initial investigations, future directions include neurosurgical planning and improved assessment of risk for individual patients, improved assessment and strategies for the treatment of chronic pain, improved seizure localization, and improved understanding of the physiology of neurological disorders. We look ahead to these and other emerging applications as the benefits of this technology become incorporated into current and future patient care. In this chapter by applying Fourier transform and wavelet transform, analysis and denoising of one of the important biomedical signals like EEG is carried out. The presence of rhythm, template matching, and correlation is discussed by various method. Energy of EEG signal is used to detect seizure in an epileptic patient. We have also performed denoising of EEG signals by SWT.

  17. The conversion of synchrotron radiation biomedical and medical images into DICOM images

    NASA Astrophysics Data System (ADS)

    Wang, Yunling; Sun, Jianyong; Sun, Jianqi; Zhang, Jianguo

    2014-03-01

    With Synchrotron Radiation light source, there was a lot of imaging methods being developed to perform biomedical and medical imaging researches such as X-ray absorption imaging, phase-contrast imaging and micro-CT imaging. In this presentation, we present an approach to transform a various kinds of SR images into proper DICOM images so that to use a rich of medical processing display software to process and display SR biomedical and medical images. The new generated SR DICOM images can be transferred, stored, processed and displayed by using most of commercial medical imaging software.

  18. Performance benchmarking of liver CT image segmentation and volume estimation

    NASA Astrophysics Data System (ADS)

    Xiong, Wei; Zhou, Jiayin; Tian, Qi; Liu, Jimmy J.; Qi, Yingyi; Leow, Wee Kheng; Han, Thazin; Wang, Shih-chang

    2008-03-01

    In recent years more and more computer aided diagnosis (CAD) systems are being used routinely in hospitals. Image-based knowledge discovery plays important roles in many CAD applications, which have great potential to be integrated into the next-generation picture archiving and communication systems (PACS). Robust medical image segmentation tools are essentials for such discovery in many CAD applications. In this paper we present a platform with necessary tools for performance benchmarking for algorithms of liver segmentation and volume estimation used for liver transplantation planning. It includes an abdominal computer tomography (CT) image database (DB), annotation tools, a ground truth DB, and performance measure protocols. The proposed architecture is generic and can be used for other organs and imaging modalities. In the current study, approximately 70 sets of abdominal CT images with normal livers have been collected and a user-friendly annotation tool is developed to generate ground truth data for a variety of organs, including 2D contours of liver, two kidneys, spleen, aorta and spinal canal. Abdominal organ segmentation algorithms using 2D atlases and 3D probabilistic atlases can be evaluated on the platform. Preliminary benchmark results from the liver segmentation algorithms which make use of statistical knowledge extracted from the abdominal CT image DB are also reported. We target to increase the CT scans to about 300 sets in the near future and plan to make the DBs built available to medical imaging research community for performance benchmarking of liver segmentation algorithms.

  19. CT & CBCT imaging: assessment of the orbits.

    PubMed

    Hatcher, David C

    2012-11-01

    The orbits can be visualized easily on routine or customized protocols for computed tomography (CT) or cone beam CT (CBCT) scans. Detailed orbital investigations are best performed with 3-dimensional imaging methods. CT scans are preferred for visualizing the osseous orbital anatomy and fissures while magnetic resonance imaging is preferred for evaluating tumors and inflammation. CBCT provides high-resolution anatomic data of the sinonasal spaces, airway, soft tissue surfaces, and bones but does not provide much detail within the soft tissues. This article discusses CBCT imaging of the orbits, osseous anatomy of the orbits, and CBCT investigation of selected orbital pathosis. PMID:22981080

  20. Medical Image Analysis Facility

    NASA Technical Reports Server (NTRS)

    1978-01-01

    To improve the quality of photos sent to Earth by unmanned spacecraft. NASA's Jet Propulsion Laboratory (JPL) developed a computerized image enhancement process that brings out detail not visible in the basic photo. JPL is now applying this technology to biomedical research in its Medical lrnage Analysis Facility, which employs computer enhancement techniques to analyze x-ray films of internal organs, such as the heart and lung. A major objective is study of the effects of I stress on persons with heart disease. In animal tests, computerized image processing is being used to study coronary artery lesions and the degree to which they reduce arterial blood flow when stress is applied. The photos illustrate the enhancement process. The upper picture is an x-ray photo in which the artery (dotted line) is barely discernible; in the post-enhancement photo at right, the whole artery and the lesions along its wall are clearly visible. The Medical lrnage Analysis Facility offers a faster means of studying the effects of complex coronary lesions in humans, and the research now being conducted on animals is expected to have important application to diagnosis and treatment of human coronary disease. Other uses of the facility's image processing capability include analysis of muscle biopsy and pap smear specimens, and study of the microscopic structure of fibroprotein in the human lung. Working with JPL on experiments are NASA's Ames Research Center, the University of Southern California School of Medicine, and Rancho Los Amigos Hospital, Downey, California.

  1. A segmentation algorithm of intracranial hemorrhage CT image

    NASA Astrophysics Data System (ADS)

    Wang, Haibo; Chen, Zhiguo; Wang, Jianzhi

    2011-10-01

    To develop a computer aided detection (CAD) system that improves diagnostic accuracy of intracranial hemorrhage on cerebral CT. A method for CT image segmentation of brain is proposed, with which, several regions that are suspicious of hemorrhage can be segmented rapidly and effectively. Extracting intracranial area algorithm is introduced firstly to extract intracranial area. Secondly, FCM is employed twice, we named it with TFCM. FCM is first employed to identify areas of intracranial hemorrhage. Finally, FCM is employed to segment the lesions. Experimental results on real medical images demonstrate the efficiency and effectiveness.

  2. Teaching about the Physics of Medical Imaging

    NASA Astrophysics Data System (ADS)

    Zollman, Dean; McBride, Dyan; Murphy, Sytil; Aryal, Bijaya; Kalita, Spartak; Wirjawan, Johannes v. d.

    2010-07-01

    Even before the discovery of X-rays, attempts at non-invasive medical imaging required an understanding of fundamental principles of physics. Students frequently do not see these connections because they are not taught in beginning physics courses. To help students understand that physics and medical imaging are closely connected, we have developed a series of active learning units. For each unit we begin by studying how students transfer their knowledge from traditional physics classes and everyday experiences to medical applications. Then, we build instructional materials to take advantage of the students' ability to use their existing learning and knowledge resources. Each of the learning units involves a combination of hands-on activities, which present analogies, and interactive computer simulations. Our learning units introduce students to the contemporary imaging techniques of CT scans, magnetic resonance imaging (MRI), positron emission tomography (PET), and wavefront aberrometry. The project's web site is http://web.phys.ksu.edu/mmmm/.

  3. Monte Carlo simulations of medical imaging modalities

    SciTech Connect

    Estes, G.P.

    1998-09-01

    Because continuous-energy Monte Carlo radiation transport calculations can be nearly exact simulations of physical reality (within data limitations, geometric approximations, transport algorithms, etc.), it follows that one should be able to closely approximate the results of many experiments from first-principles computations. This line of reasoning has led to various MCNP studies that involve simulations of medical imaging modalities and other visualization methods such as radiography, Anger camera, computerized tomography (CT) scans, and SABRINA particle track visualization. It is the intent of this paper to summarize some of these imaging simulations in the hope of stimulating further work, especially as computer power increases. Improved interpretation and prediction of medical images should ultimately lead to enhanced medical treatments. It is also reasonable to assume that such computations could be used to design new or more effective imaging instruments.

  4. From radio-astronomy to medical imaging.

    PubMed

    Peters, T M

    1991-12-01

    A common thread in much of the medical imaging that has developed over the past 20 years has been the Fourier transform. It was Richard Bates' interest in radio-interferometry, as well as his fascination with problems of medical imaging that prompted an initial interest in applying Fourier techniques to medical imaging in general and to Computed Tomography in particular. This resulted 20 years ago in one of the earliest technical papers advocating Fourier techniques for reconstructing cross-sections from radiographic projections (Bates and Peters, NZ J Science 14:883-896, 1971). Since those early days, medical imaging has explored into a multi-billion dollar industry. The CT scanner has become the workhorse imaging modality in the radiology department, while its more recent relative, the MR scanner, is rapidly gaining ground as a technique of even greater importance. Richard Bates, with his team of "Medical Imagers" was a very significant force in the development of the field of Medical Imaging as we know it today. This paper attempts to chronicle the genesis of this process from the personal perspective of the author. PMID:1789769

  5. X-ray CT and NMR imaging of rocks

    SciTech Connect

    Vinegar, H.J.

    1986-03-01

    In little more than a decade, X-ray computerized tomography (CT) and nuclear magnetic resonance (NMR) imaging have become the premier modalities of medical radiology. Both of these imaging techniques also promise to be useful tools in petrophysics and reservoir engineering, because CT and NMR can nondestructively image a host of physical and chemical properties of porous rocks and multiple fluid phases contained within their pores. The images are taken within seconds to minutes, at reservoir temperatures and pressures, with spatial resolution on the millimeter and submillimeter level. The physical properties imaged by the two techniques are complementary. CT images bulk density and effective atomic number. NMR images the nuclide concentration, M/sub 0/, of a variety of nuclei (/sup 1/H, /sup 19/F, /sup 23/Na, /sup 31/P, etc.), their longitudinal and transverse relaxation-time curves (t/sub 1/ and t/sub 2/), and their chemical shift spectra. In rocks, CT images both rock matrix and pore fluids, while NMR images only mobile fluids and the interactions of these mobile fluids with the confining surfaces of the pores.

  6. Medical alert bracelet (image)

    MedlinePlus

    People with diabetes should always wear a medical alert bracelet or necklace that emergency medical workers will ... People with diabetes should always wear a medical alert bracelet or necklace that emergency medical workers will ...

  7. CT imaging with a mobile C-arm prototype

    NASA Astrophysics Data System (ADS)

    Cheryauka, Arvi; Tubbs, David; Langille, Vinton; Kalya, Prabhanjana; Smith, Brady; Cherone, Rocco

    2008-03-01

    Mobile X-ray imagery is an omnipresent tool in conventional musculoskeletal and soft tissue applications. The next generation of mobile C-arm systems can provide clinicians of minimally-invasive surgery and pain management procedures with both real-time high-resolution fluoroscopy and intra-operative CT imaging modalities. In this study, we research two C-arm CT experimental system configurations and evaluate their imaging capabilities. In a non-destructive evaluation configuration, the X-ray Tube - Detector assembly is stationary while an imaging object is placed on a rotating table. In a medical imaging configuration, the C-arm gantry moves around the patient and the table. In our research setting, we connect the participating devices through a Mobile X-Ray Imaging Environment known as MOXIE. MOXIE is a set of software applications for internal research at GE Healthcare - Surgery and used to examine imaging performance of experimental systems. Anthropomorphic phantom volume renderings and orthogonal slices of reconstructed images are obtained and displayed. The experimental C-arm CT results show CT-like image quality that may be suitable for interventional procedures, real-time data management, and, therefore, have great potential for effective use on the clinical floor.

  8. CT Image Presentations For Oral Surgery

    NASA Astrophysics Data System (ADS)

    Rhodes, Michael L.; Rothman, Stephen L. G.; Schwarz, Melvyn S.; Tivattanasuk, Eva S.

    1988-06-01

    Reformatted CT images of the mandible and maxilla are described as a planning aid to the surgical implantation of dental fixtures. Precisely scaled and cross referenced axial, oblique, CT generated panorex, and 3-D images are generated to help indicate where and how critical anatomic structures are positioned. This information guides the oral surgeon to those sites where dental implants have optimal osteotic support and least risk to sensitive neural tissue. Oblique images are generated at 1-2 mm increments along the arch of the mandible (or maxilla). Each oblique is oriented perpendicular to the local arch curvature. The adjoining five CT generated panorex views match the patient's mandibular (or maxilla) arch, with each of the views separated by twice the distance between axial CT slices. All views are mutually cross-referenced to show fine detail of the underlying mandibular (or maxilla) structure. Several exams are illustrated and benefit to subsequent surgery is assessed.

  9. Medical alert bracelet (image)

    MedlinePlus

    People with diabetes should always wear a medical alert bracelet or necklace that emergency medical workers will be able to find. Medical identification products can help ensure proper treatment in an ...

  10. Bariatric CT Imaging: Challenges and Solutions.

    PubMed

    Fursevich, Dzmitry M; LiMarzi, Gary M; O'Dell, Matthew C; Hernandez, Manuel A; Sensakovic, William F

    2016-01-01

    The obesity epidemic in the adult and pediatric populations affects all aspects of health care, including diagnostic imaging. With the increasing prevalence of obese and morbidly obese patients, bariatric computed tomographic (CT) imaging is becoming common in day-to-day radiology practice, and a basic understanding of the unique problems that bariatric patients pose to the imaging community is crucial in any setting. Because larger patients may not fit into conventional scanners, having a CT scanner with an adequate table load limit, a large gantry aperture, a large scan field of view, and a high-power generator is a prerequisite for bariatric imaging. Iterative reconstruction methods, high tube current, and high tube voltage can reduce the image noise that is frequently seen in bariatric CT images. Truncation artifacts, cropping artifacts, and ring artifacts frequently complicate the interpretation of CT images of larger patients. If recognized, these artifacts can be easily reduced by using the proper CT equipment, scan acquisition parameters, and postprocessing options. Lastly, because of complex contrast material dynamics, contrast material-enhanced studies of bariatric patients require special attention. Understanding how the rate of injection, the scan timing, and the total mass of iodine affect vascular and parenchymal enhancement will help to optimize contrast-enhanced studies in the bariatric population. This article familiarizes the reader with the challenges that are frequently encountered at CT imaging of bariatric patients, beginning with equipment selection and ending with a review of the most commonly encountered obesity-related artifacts and the technical considerations in the acquisition of contrast-enhanced images. (©)RSNA, 2016. PMID:27232505

  11. A cloud-based medical image repository

    NASA Astrophysics Data System (ADS)

    Maeder, Anthony J.; Planitz, Birgit M.; El Rifai, Diaa

    2012-02-01

    Many widely used digital medical image collections have been established but these are generally used as raw data sources without related image analysis toolsets. Providing associated functionality to allow specific types of operations to be performed on these images has proved beneficial in some cases (e.g. brain image registration and atlases). However, toolset development to provide generic image analysis functions on medical images has tended to be ad hoc, with Open Source options proliferating (e.g. ITK). Our Automated Medical Image Collection Annotation (AMICA) system is both an image repository, to which the research community can contribute image datasets, and a search/retrieval system that uses automated image annotation. AMICA was designed for the Windows Azure platform to leverage the flexibility and scalability of the cloud. It is intended that AMICA will expand beyond its initial pilot implementation (for brain CT, MR images) to accommodate a wide range of modalities and anatomical regions. This initiative aims to contribute to advances in clinical research by permitting a broader use and reuse of medical image data than is currently attainable. For example, cohort studies for cases with particular physiological or phenotypical profiles will be able to source and include enough cases to provide high statistical power, allowing more individualised risk factors to be assessed and thus allowing screening and staging processes to be optimised. Also, education, training and credentialing of clinicians in image interpretation, will be more effective because it will be possible to select instances of images with specific visual aspects, or correspond to types of cases where reading performance improvement is desirable.

  12. SPARSE: Seed Point Auto-Generation for Random Walks Segmentation Enhancement in medical inhomogeneous targets delineation of morphological MR and CT images.

    PubMed

    Chen, Haibin; Zhen, Xin; Gu, Xuejun; Yan, Hao; Cervino, Laura; Xiao, Yang; Zhou, Linghong

    2015-01-01

    In medical image processing, robust segmentation of inhomogeneous targets is a challenging problem. Because of the complexity and diversity in medical images, the commonly used semiautomatic segmentation algorithms usually fail in the segmentation of inhomogeneous objects. In this study, we propose a novel algorithm imbedded with a seed point autogeneration for random walks segmentation enhancement, namely SPARSE, for better segmentation of inhomogeneous objects. With a few user-labeled points, SPARSE is able to generate extended seed points by estimating the probability of each voxel with respect to the labels. The random walks algorithm is then applied upon the extended seed points to achieve improved segmentation result. SPARSE is implemented under the compute unified device architecture (CUDA) programming environment on graphic processing unit (GPU) hardware platform. Quantitative evaluations are performed using clinical homogeneous and inhomogeneous cases. It is found that the SPARSE can greatly decrease the sensitiveness to initial seed points in terms of location and quantity, as well as the freedom of selecting parameters in edge weighting function. The evaluation results of SPARSE also demonstrate substantial improvements in accuracy and robustness to inhomogeneous target segmentation over the original random walks algorithm. PMID:26103201

  13. Evolution of Medical Imaging and Computational Demands

    NASA Astrophysics Data System (ADS)

    Deans, Stanley R.

    2000-11-01

    The first medical images produced using x-rays appeared less than a year after the discovery of x-rays by Wilhelm Roentgen in 1895. For over a century x-ray projection radiography has been and continues to be the most widely used diagnostic imaging modality. For over seventy years mathematics and computational methods were used in a general way for image processing and analysis. The really challenging mathematical and computational problems did not emerge until the 1970s with the beginning of computed tomography (CT) to produce images popularly known as CAT (computer-assisted tomography) scans. This was followed rapidly by positron-emission tomography (PET) and single photon emission computed tomography (SPECT). Magnetic resonance imaging (MRI) emerged in the 1980s and is in many ways the most informative medical imaging methodology. Computer-based mathematical methods are fundamental to the success of these imaging modalities, and are increasingly important in several other novel imaging techniques. The technologies involved in each modality are competely different, have varying diagnostic value, and are described by different fundamental equations. The common underlying theme is that of the reconstruction of important characteristics of medical interest from indirect measurements. Several of these methodologies for visualizing internal body anatomy and function will be discussed and related to the evolution of computational capabilities. This brings out aspects of these biomedical imaging technologies where a deeper understanding is needed, and to frontiers where future advances are likely to come from continued research in physics jointly with the mathematical sciences.

  14. Advances in CT imaging for urolithiasis

    PubMed Central

    Andrabi, Yasir; Patino, Manuel; Das, Chandan J.; Eisner, Brian; Sahani, Dushyant V.; Kambadakone, Avinash

    2015-01-01

    Urolithiasis is a common disease with increasing prevalence worldwide and a lifetime-estimated recurrence risk of over 50%. Imaging plays a critical role in the initial diagnosis, follow-up and urological management of urinary tract stone disease. Unenhanced helical computed tomography (CT) is highly sensitive (>95%) and specific (>96%) in the diagnosis of urolithiasis and is the imaging investigation of choice for the initial assessment of patients with suspected urolithiasis. The emergence of multi-detector CT (MDCT) and technological innovations in CT such as dual-energy CT (DECT) has widened the scope of MDCT in the stone disease management from initial diagnosis to encompass treatment planning and monitoring of treatment success. DECT has been shown to enhance pre-treatment characterization of stone composition in comparison with conventional MDCT and is being increasingly used. Although CT-related radiation dose exposure remains a valid concern, the use of low-dose MDCT protocols and integration of newer iterative reconstruction algorithms into routine CT practice has resulted in a substantial decrease in ionizing radiation exposure. In this review article, our intent is to discuss the role of MDCT in the diagnosis and post-treatment evaluation of urolithiasis and review the impact of emerging CT technologies such as dual energy in clinical practice. PMID:26166961

  15. Advances in CT imaging for urolithiasis.

    PubMed

    Andrabi, Yasir; Patino, Manuel; Das, Chandan J; Eisner, Brian; Sahani, Dushyant V; Kambadakone, Avinash

    2015-01-01

    Urolithiasis is a common disease with increasing prevalence worldwide and a lifetime-estimated recurrence risk of over 50%. Imaging plays a critical role in the initial diagnosis, follow-up and urological management of urinary tract stone disease. Unenhanced helical computed tomography (CT) is highly sensitive (>95%) and specific (>96%) in the diagnosis of urolithiasis and is the imaging investigation of choice for the initial assessment of patients with suspected urolithiasis. The emergence of multi-detector CT (MDCT) and technological innovations in CT such as dual-energy CT (DECT) has widened the scope of MDCT in the stone disease management from initial diagnosis to encompass treatment planning and monitoring of treatment success. DECT has been shown to enhance pre-treatment characterization of stone composition in comparison with conventional MDCT and is being increasingly used. Although CT-related radiation dose exposure remains a valid concern, the use of low-dose MDCT protocols and integration of newer iterative reconstruction algorithms into routine CT practice has resulted in a substantial decrease in ionizing radiation exposure. In this review article, our intent is to discuss the role of MDCT in the diagnosis and post-treatment evaluation of urolithiasis and review the impact of emerging CT technologies such as dual energy in clinical practice. PMID:26166961

  16. Intelligent distributed medical image management

    NASA Astrophysics Data System (ADS)

    Garcia, Hong-Mei C.; Yun, David Y.

    1995-05-01

    The rapid advancements in high performance global communication have accelerated cooperative image-based medical services to a new frontier. Traditional image-based medical services such as radiology and diagnostic consultation can now fully utilize multimedia technologies in order to provide novel services, including remote cooperative medical triage, distributed virtual simulation of operations, as well as cross-country collaborative medical research and training. Fast (efficient) and easy (flexible) retrieval of relevant images remains a critical requirement for the provision of remote medical services. This paper describes the database system requirements, identifies technological building blocks for meeting the requirements, and presents a system architecture for our target image database system, MISSION-DBS, which has been designed to fulfill the goals of Project MISSION (medical imaging support via satellite integrated optical network) -- an experimental high performance gigabit satellite communication network with access to remote supercomputing power, medical image databases, and 3D visualization capabilities in addition to medical expertise anywhere and anytime around the country. The MISSION-DBS design employs a synergistic fusion of techniques in distributed databases (DDB) and artificial intelligence (AI) for storing, migrating, accessing, and exploring images. The efficient storage and retrieval of voluminous image information is achieved by integrating DDB modeling and AI techniques for image processing while the flexible retrieval mechanisms are accomplished by combining attribute- based and content-based retrievals.

  17. Interhospital CT image communication: T-1 line versus courier service

    NASA Astrophysics Data System (ADS)

    Lou, Shyhliang A.; Huang, H. K.; Bazzill, Todd M.; Gould, Robert G.; Dillon, William P.; Schomer, Barbara G.

    1995-05-01

    The Mount Zion Hospital (MZH) in San Francisco, Calif. is associated with the University of California at San Francisco (UCSF) medical center. These hospitals are approximately two miles apart. The UCSF radiology department supports specialty image reading for MZH daily. The major issue involved with this service is the access of patient images. Currently, the patient image access is through two ways: (1) inter-hospital travel, and (2) image delivery. Both methods are neither efficient nor economic. If patient images can be transferred from MZH to UCSF to be viewed in digital form in a reasonable time period, the issue of patient image accession can be resolved. This study attempts to use an available digital communication technology, a T-1 line, to verify this hypothesis. The study is centered on the comparison between the T-1 line and courier service with respect to cost and image delivery performance. This comparison study focuses on CT images with an emphasis on neuroradiology application.

  18. Prior CT imaging history for patients who undergo PAN CT for acute traumatic injury

    PubMed Central

    Kenter, Jeremy; Blow, Osbert; Krall, Scott P.; Gest, Albert; Smith, Cynthia

    2015-01-01

    Objective. A single PAN scan may provide more radiation to a patient than is felt to be safe within a one-year period. Our objective was to determine how many patients admitted to the trauma service following a PAN scan had prior CT imaging within our six-hospital system. Methods. We performed a secondary analysis of a prospectively collected trauma registry. The study was based at a level-two trauma center and five affiliated hospitals, which comprise 70.6% of all Emergency Department visits within a twelve county region of southern Texas. Electronic medical records were reviewed dating from the point of trauma evaluation back to December 5, 2005 to determine evidence of prior CT imaging. Results. There were 867 patients were admitted to the trauma service between January 1, 2012 and December 31, 2012. 460 (53%) received a PAN scan and were included in the study group. The mean age of the study group was 37.7 ± 1.54 years old, 24.8% were female, and the mean ISS score was 13.4 ± 1.07. The most common mechanism of injury was motor vehicle collision (47%). 65 (14%; 95% CI [11–18]%) of the patients had at least one prior CT. The most common prior studies performed were: CT head (29%; 19–42%), CT Face (29%; 19–42%) and CT Abdomen and Pelvis (18%; 11–30%). Conclusion. Within our trauma registry, 14% of patients had prior CT imaging within our hospital system before their traumatic event and PAN scan. PMID:26056616

  19. CT image registration in sinogram space

    SciTech Connect

    Mao Weihua; Li Tianfang; Wink, Nicole; Xing Lei

    2007-09-15

    Object displacement in a CT scan is generally reflected in CT projection data or sinogram. In this work, the direct relationship between object motion and the change of CT projection data (sinogram) is investigated and this knowledge is applied to create a novel algorithm for sinogram registration. Calculated and experimental results demonstrate that the registration technique works well for registering rigid 2D or 3D motion in parallel and fan beam samplings. Problem and solution for 3D sinogram-based registration of metallic fiducials are also addressed. Since the motion is registered before image reconstruction, the presented algorithm is particularly useful when registering images with metal or truncation artifacts. In addition, this algorithm is valuable for dealing with situations where only limited projection data are available, making it appealing for various applications in image guided radiation therapy.

  20. Seamless Insertion of Pulmonary Nodules in Chest CT Images.

    PubMed

    Pezeshk, Aria; Sahiner, Berkman; Zeng, Rongping; Wunderlich, Adam; Chen, Weijie; Petrick, Nicholas

    2015-12-01

    The availability of large medical image datasets is critical in many applications, such as training and testing of computer-aided diagnosis systems, evaluation of segmentation algorithms, and conducting perceptual studies. However, collection of data and establishment of ground truth for medical images are both costly and difficult. To address this problem, we are developing an image blending tool that allows users to modify or supplement existing datasets by seamlessly inserting a lesion extracted from a source image into a target image. In this study, we focus on the application of this tool to pulmonary nodules in chest CT exams. We minimize the impact of user skill on the perceived quality of the composite image by limiting user involvement to two simple steps: the user first draws a casual boundary around a nodule in the source, and, then, selects the center of desired insertion area in the target. We demonstrate the performance of our system on clinical samples, and report the results of a reader study evaluating the realism of inserted nodules compared to clinical nodules. We further evaluate our image blending techniques using phantoms simulated under different noise levels and reconstruction filters. Specifically, we compute the area under the ROC curve of the Hotelling observer (HO) and noise power spectrum of regions of interest enclosing native and inserted nodules, and compare the detectability, noise texture, and noise magnitude of inserted and native nodules. Our results indicate the viability of our approach for insertion of pulmonary nodules in clinical CT images. PMID:26080378

  1. State-of-the-Art CT Imaging Techniques for Congenital Heart Disease

    PubMed Central

    2010-01-01

    CT is increasingly being used for evaluating the cardiovascular structures and airways in the patients with congenital heart disease. Multi-slice CT has traditionally been used for the evaluation of the extracardiac vascular and airway abnormalities because of its inherent high spatial resolution and excellent air-tissue contrast. Recent developments in CT technology primarily by reducing the cardiac motion and the radiation dose usage in congenital heart disease evaluation have helped expand the indications for CT usage. Tracheobronchomalacia associated with congenital heart disease can be evaluated with cine CT. Intravenous contrast injection should be tailored to unequivocally demonstrate cardiovascular abnormalities. Knowledge of the state-of-the-art CT imaging techniques that are used for evaluating congenital heart disease is helpful not only for planning and performing CT examinations, but also for interpreting and presenting the CT image findings that consequently guide the proper medical and surgical management. PMID:20046490

  2. Medical Imaging Inspired Vertex Reconstruction at LHC

    NASA Astrophysics Data System (ADS)

    Hageböck, S.; von Toerne, E.

    2012-12-01

    Three-dimensional image reconstruction in medical applications (PET or X-ray CT) utilizes sophisticated filter algorithms to linear trajectories of coincident photon pairs or x-rays. The goal is to reconstruct an image of an emitter density distribution. In a similar manner, tracks in particle physics originate from vertices that need to be distinguished from background track combinations. In this study it is investigated if vertex reconstruction in high energy proton collisions may benefit from medical imaging methods. A new method of vertex finding, the Medical Imaging Vertexer (MIV), is presented based on a three-dimensional filtered backprojection algorithm. It is compared to the open-source RAVE vertexing package. The performance of the vertex finding algorithms is evaluated as a function of instantaneous luminosity using simulated LHC collisions. Tracks in these collisions are described by a simplified detector model which is inspired by the tracking performance of the LHC experiments. At high luminosities (25 pileup vertices and more), the medical imaging approach finds vertices with a higher efficiency and purity than the RAVE “Adaptive Vertex Reconstructor” algorithm. It is also much faster if more than 25 vertices are to be reconstructed because the amount of CPU time rises linearly with the number of tracks whereas it rises quadratically for the adaptive vertex fitter AVR.

  3. Medical hyperspectral imaging: a review

    NASA Astrophysics Data System (ADS)

    Lu, Guolan; Fei, Baowei

    2014-01-01

    Hyperspectral imaging (HSI) is an emerging imaging modality for medical applications, especially in disease diagnosis and image-guided surgery. HSI acquires a three-dimensional dataset called hypercube, with two spatial dimensions and one spectral dimension. Spatially resolved spectral imaging obtained by HSI provides diagnostic information about the tissue physiology, morphology, and composition. This review paper presents an overview of the literature on medical hyperspectral imaging technology and its applications. The aim of the survey is threefold: an introduction for those new to the field, an overview for those working in the field, and a reference for those searching for literature on a specific application.

  4. Medical hyperspectral imaging: a review

    PubMed Central

    Lu, Guolan; Fei, Baowei

    2014-01-01

    Abstract. Hyperspectral imaging (HSI) is an emerging imaging modality for medical applications, especially in disease diagnosis and image-guided surgery. HSI acquires a three-dimensional dataset called hypercube, with two spatial dimensions and one spectral dimension. Spatially resolved spectral imaging obtained by HSI provides diagnostic information about the tissue physiology, morphology, and composition. This review paper presents an overview of the literature on medical hyperspectral imaging technology and its applications. The aim of the survey is threefold: an introduction for those new to the field, an overview for those working in the field, and a reference for those searching for literature on a specific application. PMID:24441941

  5. Hybrid SPECT/CT imaging in neurology.

    PubMed

    Ciarmiello, Andrea; Giovannini, Elisabetta; Meniconi, Martina; Cuccurullo, Vincenzo; Gaeta, Maria Chiara

    2014-01-01

    In recent years, the SPECT/CT hybrid modality has led to a rapid development of imaging techniques in nuclear medicine, opening new perspectives for imaging staff and patients as well. However, while, the clinical role of positron emission tomography-computed tomography (PET-CT) is well consolidated, the diffusion and the consequent value of single-photon emission tomography-computed tomography (SPECT-CT) has yet to be weighed, Hence, there is a need for a careful analysis, comparing the "potential" benefits of the hybrid modality with the "established" ones of the standalone machine. The aim of this article is to analyze the impact of this hybrid tool on the diagnosis of diseases of the central nervous system, comparing strengths and weaknesses of both modalities through the use of SWOT analysis. PMID:25143053

  6. Spiral CT image deblurring for cochlear implantation.

    PubMed

    Wang, G; Vannier, M W; Skinner, M W; Cavalcanti, M G; Harding, G W

    1998-04-01

    Cochlear implantation is the standard treatment for profound hearing loss. Preimplantation and postimplantation spiral computed tomography (CT) is essential in several key clinical and research aspects. The maximum image resolution with commercial spiral CT scanners is insufficient to define clearly anatomical features and implant electrode positions in the inner ear. In this paper, we develop an expectation-maximization (EM)-like iterative deblurring algorithm to achieve spiral CT image super-resolution for cochlear implantation, assuming a spatially invariant linear spiral CT system with a three-dimensional (3-D) separable Gaussian point spread function (PSF). We experimentally validate the 3-D Gaussian blurring model via phantom measurement and profile fitting. The imaging process is further expressed as convolution of an isotropic 3-D Gaussian PSF and a blurred underlying volumetric image. Under practical conditions, an oblique reconstructed section is approximated as convolution of an isotropic two-dimensional (2-D) Gaussian PSF and the corresponding actual cross section. The spiral CT image deblurring algorithm is formulated with sieve and resolution kernels for suppressing noise and edge artifacts. A typical cochlear cross section is used for evaluation, demonstrating a resolution gain up to 30%40% according to the correlation criterion. Physical phantoms, preimplantation and postimplantation patients are reconstructed into volumes of 0.1-mm cubic voxels. The patient images are digitally unwrapped along the central axis of the cochlea and the implanted electrode array respectively, then oblique sections orthogonal to the central axis formed. After deblurring, representation of structural features is substantially improved in all the cases. PMID:9688157

  7. CT Image Processing Using Public Digital Networks

    PubMed Central

    Rhodes, Michael L.; Azzawi, Yu-Ming; Quinn, John F.; Glenn, William V.; Rothman, Stephen L.G.

    1984-01-01

    Nationwide commercial computer communication is now commonplace for those applications where digital dialogues are generally short and widely distributed, and where bandwidth does not exceed that of dial-up telephone lines. Image processing using such networks is prohibitive because of the large volume of data inherent to digital pictures. With a blend of increasing bandwidth and distributed processing, network image processing becomes possible. This paper examines characteristics of a digital image processing service for a nationwide network of CT scanner installations. Issues of image transmission, data compression, distributed processing, software maintenance, and interfacility communication are also discussed. Included are results that show the volume and type of processing experienced by a network of over 50 CT scanners for the last 32 months.

  8. CT imaging of enhanced oil recovery experiments

    SciTech Connect

    Gall, B.L.

    1992-12-01

    X-ray computerized tomography (Cr) has been used to study fluid distributions during chemical enhanced oil recovery experiments. Four CT-monitored corefloods were conducted, and oil saturation distributions were calculated at various stages of the experiments. Results suggested that this technique could add significant information toward interpretation and evaluation of surfactant/polymer EOR recovery methods. CT-monitored tracer tests provided information about flow properties in the core samples. Nonuniform fluid advance could be observed, even in core that appeared uniform by visual inspection. Porosity distribution maps based on CT density calculations also showed the presence of different porosity layers that affected fluid movement through the cores. Several types of CT-monitored corefloods were conducted. Comparisons were made for CT-monitored corefloods using chemical systems that were highly successful in reducing residual oil saturations in laboratory experiments and less successful systems. Changes were made in surfactant formulation and in concentration of the mobility control polymer. Use of a poor mobility control agent failed to move oil that was not initially displaced by the injected surfactant solution; even when a good'' surfactant system was used. Use of a less favorable surfactant system with adequate mobility control could produce as much oil as the use of a good surfactant system with inadequate mobility control. The role of mobility control, therefore, becomes a critical parameter for successful application of chemical EOR. Continuation of efforts to use CT imaging in connection with chemical EOR evaluations is recommended.

  9. CT imaging of enhanced oil recovery experiments

    SciTech Connect

    Gall, B.L.

    1992-12-01

    X-ray computerized tomography (Cr) has been used to study fluid distributions during chemical enhanced oil recovery experiments. Four CT-monitored corefloods were conducted, and oil saturation distributions were calculated at various stages of the experiments. Results suggested that this technique could add significant information toward interpretation and evaluation of surfactant/polymer EOR recovery methods. CT-monitored tracer tests provided information about flow properties in the core samples. Nonuniform fluid advance could be observed, even in core that appeared uniform by visual inspection. Porosity distribution maps based on CT density calculations also showed the presence of different porosity layers that affected fluid movement through the cores. Several types of CT-monitored corefloods were conducted. Comparisons were made for CT-monitored corefloods using chemical systems that were highly successful in reducing residual oil saturations in laboratory experiments and less successful systems. Changes were made in surfactant formulation and in concentration of the mobility control polymer. Use of a poor mobility control agent failed to move oil that was not initially displaced by the injected surfactant solution; even when a ``good`` surfactant system was used. Use of a less favorable surfactant system with adequate mobility control could produce as much oil as the use of a good surfactant system with inadequate mobility control. The role of mobility control, therefore, becomes a critical parameter for successful application of chemical EOR. Continuation of efforts to use CT imaging in connection with chemical EOR evaluations is recommended.

  10. The appearance and effects of metallic implants in CT images.

    PubMed

    Kairn, T; Crowe, S B; Fogg, P; Trapp, J V

    2013-06-01

    The computed tomography (CT) imaging artefacts that metallic medical implants produce in surrounding tissues are usually contoured and over-ridden during radiotherapy treatment planning. In cases where radiotherapy treatment beams unavoidably pass though implants, it is especially important to understand the imaging artefacts that may occur within the implants themselves. This study examines CT images of a set of simple metallic objects, immersed in water, in order to evaluate reliability and variability of CT numbers (Hounsfield units, HUs) within medical implants. Model implants with a range of sizes (heights from 2.2 to 49.6 mm), electron densities (from 2.3 to 7.7 times the electron density of water) and effective atomic numbers (from 3.9 to 9.0 times the effective atomic number of water in a CT X-ray beam) were created by stacking metal coins from several currencies. These 'implants' were CT scanned within a large (31.0 cm across) and a small (12.8 cm across) water phantom. Resulting HU values are as much as 50 % lower than the result of extrapolating standard electron density calibration data (obtained for tissue and bone densities) up to the metal densities and there is a 6 % difference between the results obtained by scanning with 120 and 140 kVp tube potentials. Profiles through the implants show localised cupping artefacts, within the implants, as well as a gradual decline in HU outside the implants that can cause the implants' sizes to be over estimated by 1.3-9.0 mm. These effects are exacerbated when the implants are scanned in the small phantom or at the side of the large phantom, due to reduced pre-hardening of the X-ray beam in these configurations. These results demonstrate the necessity of over-riding the densities of metallic implants, as well as their artefacts in tissue, in order to obtain accurate radiotherapy dose calculations. PMID:23760920

  11. [Medical image compression: a review].

    PubMed

    Noreña, Tatiana; Romero, Eduardo

    2013-01-01

    Modern medicine is an increasingly complex activity , based on the evidence ; it consists of information from multiple sources : medical record text , sound recordings , images and videos generated by a large number of devices . Medical imaging is one of the most important sources of information since they offer comprehensive support of medical procedures for diagnosis and follow-up . However , the amount of information generated by image capturing gadgets quickly exceeds storage availability in radiology services , generating additional costs in devices with greater storage capacity . Besides , the current trend of developing applications in cloud computing has limitations, even though virtual storage is available from anywhere, connections are made through internet . In these scenarios the optimal use of information necessarily requires powerful compression algorithms adapted to medical activity needs . In this paper we present a review of compression techniques used for image storage , and a critical analysis of them from the point of view of their use in clinical settings. PMID:23715317

  12. Integration of Medical Imaging Including Ultrasound into a New Clinical Anatomy Curriculum

    ERIC Educational Resources Information Center

    Moscova, Michelle; Bryce, Deborah A.; Sindhusake, Doungkamol; Young, Noel

    2015-01-01

    In 2008 a new clinical anatomy curriculum with integrated medical imaging component was introduced into the University of Sydney Medical Program. Medical imaging used for teaching the new curriculum included normal radiography, MRI, CT scans, and ultrasound imaging. These techniques were incorporated into teaching over the first two years of the…

  13. Imaging features of rhinosporidiosis on contrast CT

    PubMed Central

    Prabhu, Shailesh M; Irodi, Aparna; Khiangte, Hannah L; Rupa, V; Naina, P

    2013-01-01

    Context: Rhinosporidiosis is a chronic granulomatous disease endemic in certain regions of India. Computed tomography (CT) imaging appearances of rhinosporidiosis have not been previously described in the literature. Aims: To study imaging features in rhinosporidiosis with contrast-enhanced CT and elucidate its role in the evaluation of this disease. Materials and Methods: Sixteen patients with pathologically proven rhinosporidiosis were included in the study. Contrast-enhanced CT images were analyzed retrospectively and imaging findings were correlated with surgical and histopathologic findings. Results: A total of 29 lesions were found and evaluated. On contrast-enhanced CT, rhinosporidiosis was seen as moderately enhancing lobulated or irregular soft tissue mass lesions in the nasal cavity (n = 13), lesions arising in nasal cavity and extending through choana into nasopharynx (n = 5), pedunculated polypoidal lesions arising from the nasopharyngeal wall (n = 5), oropharyngeal wall (n = 2), larynx (n = 1), bronchus (n = 1), skin and subcutaneous tissue (n = 2). The inferior nasal cavity comprising nasal floor, inferior turbinate, and inferior meatus was the most common site of involvement (n = 13). Surrounding bone involvement was seen in the form of rarefaction (n = 6), partial (n = 3) or complete erosion (n = 3) of inferior turbinate, thinning of medial maxillary wall (n = 2), and septal erosion (n = 2). Nasolacrimal duct involvement was seen in four cases. Conclusions: Contrast-enhanced CT has an important role in delineating the site and extent of the disease, as well as the involvement of surrounding bone, nasolacrimal duct and tracheobronchial tree. This provides a useful roadmap prior to surgery. PMID:24347850

  14. Cardiac CT Imaging of Plaque Vulnerability: Hype or Hope?

    PubMed

    Willemink, Martin J; Leiner, Tim; Maurovich-Horvat, Pál

    2016-03-01

    Advances in cardiovascular computed tomography (CT) have resulted in an excellent ability to exclude coronary heart disease (CHD). Anatomical information, functional information, and spectral information can already be obtained with current CT technologies. Moreover, novel developments such as targeted nanoparticle contrast agents, photon-counting CT, and phase contrast CT will further enhance the diagnostic value of cardiovascular CT. This review provides an overview of current state of the art and future cardiovascular CT imaging. PMID:26922591

  15. Compressive sensing in medical imaging

    PubMed Central

    Graff, Christian G.; Sidky, Emil Y.

    2015-01-01

    The promise of compressive sensing, exploitation of compressibility to achieve high quality image reconstructions with less data, has attracted a great deal of attention in the medical imaging community. At the Compressed Sensing Incubator meeting held in April 2014 at OSA Headquarters in Washington, DC, presentations were given summarizing some of the research efforts ongoing in compressive sensing for x-ray computed tomography and magnetic resonance imaging systems. This article provides an expanded version of these presentations. Sparsity-exploiting reconstruction algorithms that have gained popularity in the medical imaging community are studied, and examples of clinical applications that could benefit from compressive sensing ideas are provided. The current and potential future impact of compressive sensing on the medical imaging field is discussed. PMID:25968400

  16. Medical Images Fusion with Patch Based Structure Tensor.

    PubMed

    Luo, Fen; Sun, Jiangfeng; Hou, Shouming

    2015-01-01

    Nowadays medical imaging has played an important role in clinical use, which provide important clues for medical diagnosis. In medical image fusion, the extraction of some fine details and description is critical. To solve this problem, a modified structure tensor by considering similarity between two patches is proposed. The patch based filter can suppress noise and add the robustness of the eigen-values of the structure tensor by allowing the use of more information of far away pixels. After defining the new structure tensor, we apply it into medical image fusion with a multi-resolution wavelet theory. The features are extracted and described by the eigen-values of two multi-modality source data. To test the performance of the proposed scheme, the CT and MR images are used as input source images for medical image fusion. The experimental results show that the proposed method can produce better results compared to some related approaches. PMID:26628927

  17. Segmentation of medical images using explicit anatomical knowledge

    NASA Astrophysics Data System (ADS)

    Wilson, Laurie S.; Brown, Stephen; Brown, Matthew S.; Young, Jeanne; Li, Rongxin; Luo, Suhuai; Brandt, Lee

    1999-07-01

    Knowledge-based image segmentation is defined in terms of the separation of image analysis procedures and representation of knowledge. Such architecture is particularly suitable for medical image segmentation, because of the large amount of structured domain knowledge. A general methodology for the application of knowledge-based methods to medical image segmentation is described. This includes frames for knowledge representation, fuzzy logic for anatomical variations, and a strategy for determining the order of segmentation from the modal specification. This method has been applied to three separate problems, 3D thoracic CT, chest X-rays and CT angiography. The application of the same methodology to such a range of applications suggests a major role in medical imaging for segmentation methods incorporating representation of anatomical knowledge.

  18. Automated Image Retrieval of Chest CT Images Based on Local Grey Scale Invariant Features.

    PubMed

    Arrais Porto, Marcelo; Cordeiro d'Ornellas, Marcos

    2015-01-01

    Textual-based tools are regularly employed to retrieve medical images for reading and interpretation using current retrieval Picture Archiving and Communication Systems (PACS) but pose some drawbacks. All-purpose content-based image retrieval (CBIR) systems are limited when dealing with medical images and do not fit well into PACS workflow and clinical practice. This paper presents an automated image retrieval approach for chest CT images based local grey scale invariant features from a local database. Performance was measured in terms of precision and recall, average retrieval precision (ARP), and average retrieval rate (ARR). Preliminary results have shown the effectiveness of the proposed approach. The prototype is also a useful tool for radiology research and education, providing valuable information to the medical and broader healthcare community. PMID:26262345

  19. Metonymies in Medical Terminologies. A SNOMED CT Case Study

    PubMed Central

    Kreuzthaler, Markus; Schulz, Stefan

    2012-01-01

    Metonymies are language phenomena, in which one expression is used to refer to a related one. Whereas there are many examples in medical discourse, it has been controversially discussed to what extent metonymic phenomena also matter in medical terminologies like SNOMED CT, where they could hamper their proper use. We investigated this by analyzing all SNOMED CT single word fully specified names containing the suffixes “-itis” and “-ectomy”. Using a combination of string and concept matching, we harvested definitional phrases from the Web and contrasted them with the terms and their logical definitions as stated in SNOMED CT. Whereas metonymic phenomena are very rare in the collection of surgical terms (two out of 138), they were found in 16 terms (out of 251) in the collection of inflammation terms. Web mining retrieved useful phrases for 11 of these terms. Most metonymies found corresponded to the “whole for part” and “general for specific” pattern. PMID:23304317

  20. Imaging-related medications: a class overview

    PubMed Central

    2007-01-01

    Imaging-related medications (contrast agents) are commonly utilized to improve visualization of radiographic, computed tomography (CT), and magnetic resonance (MR) images. While traditional medications are used specifically for their pharmacological actions, the ideal imaging agent provides enhanced contrast with little biological interaction. The radiopaque agents, barium sulfate and iodinated contrast agents, confer “contrast” to x-ray films by their physical ability to directly absorb x-rays. Gadolinium-based MR agents enhance visualization of tissues when exposed to a magnetic field. Ferrous-ferric oxide–based paramagnetic agents provide negative contrast for MR liver studies. This article provides an overview of clinically relevant information for the imaging-related medications commonly in use. It reviews the safety improvements in new generations of drugs; risk factors and precautions for the reduction of severe adverse reactions (i.e., extravasation, contrast-induced nephropathy, metformin-induced lactic acidosis, and nephrogenic fibrosing dermopathy/nephrogenic systemic fibrosis); and the significance of diligent patient screening before contrast exposure and appropriate monitoring after exposure. PMID:17948119

  1. Recommendations of the Spanish Societies of Radiation Oncology (SEOR), Nuclear Medicine & Molecular Imaging (SEMNiM), and Medical Physics (SEFM) on 18F-FDG PET-CT for radiotherapy treatment planning

    PubMed Central

    Caballero Perea, Begoña; Villegas, Antonio Cabrera; Rodríguez, José Miguel Delgado; Velloso, María José García; Vicente, Ana María García; Cabrerizo, Carlos Huerga; López, Rosa Morera; Romasanta, Luis Alberto Pérez; Beltrán, Moisés Sáez

    2012-01-01

    Positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) is a valuable tool for diagnosing and staging malignant lesions. The fusion of PET and computed tomography (CT) yields images that contain both metabolic and morphological information, which, taken together, have improved the diagnostic precision of PET in oncology. The main imaging modality for planning radiotherapy treatment is CT. However, PET-CT is an emerging modality for use in planning treatments because it allows for more accurate treatment volume definition. The use of PET-CT for treatment planning is highly complex, and protocols and standards for its use are still being developed. It seems probable that PET-CT will eventually replace current CT-based planning methods, but this will require a full understanding of the relevant technical aspects of PET-CT planning. The aim of the present document is to review these technical aspects and to provide recommendations for clinical use of this imaging modality in the radiotherapy planning process. PMID:24377032

  2. Discovering Hominins - Application of Medical Computed Tomography (CT) to Fossil-Bearing Rocks from the Site of Malapa, South Africa.

    PubMed

    Smilg, Jacqueline S; Berger, Lee R

    2015-01-01

    In the South African context, computed tomography (CT) has been used applied to individually prepared fossils and small rocks containing fossils, but has not been utilized on large breccia blocks as a means of discovering fossils, and particularly fossil hominins. Previous attempts at CT imaging of rocks from other South African sites for this purpose yielded disappointing results. For this study, 109 fossil- bearing rocks from the site of Malapa, South Africa were scanned with medical CT prior to manual preparation. The resultant images were assessed for accuracy of fossil identification and characterization against the standard of manual preparation. The accurate identification of fossils, including those of early hominins, that were not visible on the surface of individual blocks, is shown to be possible. The discovery of unexpected fossils is reduced, thus lowering the potential that fossils could be damaged through accidental encounter during routine preparation, or even entirely missed. This study should significantly change the way fossil discovery, recovery and preparation is done in the South African context and has potential for application in other palaeontological situations. Medical CT imaging is shown to be reliable, readily available, cost effective and accurate in finding fossils within matrix conglomerates. Improvements in CT equipment and in CT image quality are such that medical CT is now a viable imaging modality for this palaeontological application. PMID:26684299

  3. Discovering Hominins - Application of Medical Computed Tomography (CT) to Fossil-Bearing Rocks from the Site of Malapa, South Africa

    PubMed Central

    Smilg, Jacqueline S.; Berger, Lee R.

    2015-01-01

    In the South African context, computed tomography (CT) has been used applied to individually prepared fossils and small rocks containing fossils, but has not been utilized on large breccia blocks as a means of discovering fossils, and particularly fossil hominins. Previous attempts at CT imaging of rocks from other South African sites for this purpose yielded disappointing results. For this study, 109 fossil- bearing rocks from the site of Malapa, South Africa were scanned with medical CT prior to manual preparation. The resultant images were assessed for accuracy of fossil identification and characterization against the standard of manual preparation. The accurate identification of fossils, including those of early hominins, that were not visible on the surface of individual blocks, is shown to be possible. The discovery of unexpected fossils is reduced, thus lowering the potential that fossils could be damaged through accidental encounter during routine preparation, or even entirely missed. This study should significantly change the way fossil discovery, recovery and preparation is done in the South African context and has potential for application in other palaeontological situations. Medical CT imaging is shown to be reliable, readily available, cost effective and accurate in finding fossils within matrix conglomerates. Improvements in CT equipment and in CT image quality are such that medical CT is now a viable imaging modality for this palaeontological application. PMID:26684299

  4. Research on Medical Image Enhancement Algorithm Based on GSM Model for Wavelet Coefficients

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Jiang, Nian-de; Ning, Xing

    For the complexity and application diversity of medical CT image, this article presents a medical CT Image enhancing algorithm based on Gaussian Scale Mixture Model for wavelet coefficient in the study of wavelet multi-scale analysis. The noisy image is firstly denoised in auto-adapted Wiener filter. Secondly, through the qualitative analysis and classification of wavelet coefficients for the signal and noise, the wavelet's approximate distribution and statistical characteristics are described, combining GSM(Gaussian scale mixture) model for wavelet coefficient in this paper. It is shown that this algorithm can improve the denoised result and enhanced the medical CT image obviously.

  5. Attenuation correction of emission PET images with average CT: Interpolation from breath-hold CT

    NASA Astrophysics Data System (ADS)

    Huang, Tzung-Chi; Zhang, Geoffrey; Chen, Chih-Hao; Yang, Bang-Hung; Wu, Nien-Yun; Wang, Shyh-Jen; Wu, Tung-Hsin

    2011-05-01

    Misregistration resulting from the difference of temporal resolution in PET and CT scans occur frequently in PET/CT imaging, which causes distortion in tumor quantification in PET. Respiration cine average CT (CACT) for PET attenuation correction has been reported to improve the misalignment effectively by several papers. However, the radiation dose to the patient from a four-dimensional CT scan is relatively high. In this study, we propose a method to interpolate respiratory CT images over a respiratory cycle from inhalation and exhalation breath-hold CT images, and use the average CT from the generated CT set for PET attenuation correction. The radiation dose to the patient is reduced using this method. Six cancer patients of various lesion sites underwent routine free-breath helical CT (HCT), respiration CACT, interpolated average CT (IACT), and 18F-FDG PET. Deformable image registration was used to interpolate the middle phases of a respiratory cycle based on the end-inspiration and end-expiration breath-hold CT scans. The average CT image was calculated from the eight interpolated CT image sets of middle respiratory phases and the two original inspiration and expiration CT images. Then the PET images were reconstructed by these three methods for attenuation correction using HCT, CACT, and IACT. Misalignment of PET image using either CACT or IACT for attenuation correction in PET/CT was improved. The difference in standard uptake value (SUV) from tumor in PET images was most significant between the use of HCT and CACT, while the least significant between the use of CACT and IACT. Besides the similar improvement in tumor quantification compared to the use of CACT, using IACT for PET attenuation correction reduces the radiation dose to the patient.

  6. Total variation minimization-based multimodality medical image reconstruction

    NASA Astrophysics Data System (ADS)

    Cui, Xuelin; Yu, Hengyong; Wang, Ge; Mili, Lamine

    2014-09-01

    Since its recent inception, simultaneous image reconstruction for multimodality fusion has received a great deal of attention due to its superior imaging performance. On the other hand, the compressed sensing (CS)-based image reconstruction methods have undergone a rapid development because of their ability to significantly reduce the amount of raw data. In this work, we combine computed tomography (CT) and magnetic resonance imaging (MRI) into a single CS-based reconstruction framework. From a theoretical viewpoint, the CS-based reconstruction methods require prior sparsity knowledge to perform reconstruction. In addition to the conventional data fidelity term, the multimodality imaging information is utilized to improve the reconstruction quality. Prior information in this context is that most of the medical images can be approximated as piecewise constant model, and the discrete gradient transform (DGT), whose norm is the total variation (TV), can serve as a sparse representation. More importantly, the multimodality images from the same object must share structural similarity, which can be captured by DGT. The prior information on similar distributions from the sparse DGTs is employed to improve the CT and MRI image quality synergistically for a CT-MRI scanner platform. Numerical simulation with undersampled CT and MRI datasets is conducted to demonstrate the merits of the proposed hybrid image reconstruction approach. Our preliminary results confirm that the proposed method outperforms the conventional CT and MRI reconstructions when they are applied separately.

  7. Medical gamma ray imaging

    DOEpatents

    Osborne, Louis S.; Lanza, Richard C.

    1984-01-01

    A method and apparatus for determining the distribution of a position-emitting radioisotope into an object, the apparatus consisting of a wire mesh radiation converter, an ionizable gas for propagating ionization events caused by electrodes released by the converter, a drift field, a spatial position detector and signal processing circuitry for correlating near-simultaneous ionization events and determining their time differences, whereby the position sources of back-to-back collinear radiation can be located and a distribution image constructed.

  8. An online interactive simulation system for medical imaging education.

    PubMed

    Dikshit, Aditya; Wu, Dawei; Wu, Chunyan; Zhao, Weizhao

    2005-09-01

    This report presents a recently developed web-based medical imaging simulation system for teaching students or other trainees who plan to work in the medical imaging field. The increased importance of computer and information technology widely applied to different imaging techniques in clinics and medical research necessitates a comprehensive medical imaging education program. A complete tutorial of simulations introducing popular imaging modalities, such as X-ray, MRI, CT, ultrasound and PET, forms an essential component of such an education. Internet technologies provide a vehicle to carry medical imaging education online. There exist a number of internet-based medical imaging hyper-books or online documentations. However, there are few providing interactive computational simulations. We focus on delivering knowledge of the physical principles and engineering implementation of medical imaging techniques through an interactive website environment. The online medical imaging simulation system presented in this report outlines basic principles underlying different imaging techniques and image processing algorithms and offers trainees an interactive virtual laboratory. For education purposes, this system aims to provide general understanding of each imaging modality with comprehensive explanations, ample illustrations and copious references as its thrust, rather than complex physics or detailed math. This report specifically describes the development of the tutorial for commonly used medical imaging modalities. An internet-accessible interface is used to simulate various imaging algorithms with user-adjustable parameters. The tutorial is under the MATLAB Web Server environment. Macromedia Director MX is used to develop interactive animations integrating theory with graphic-oriented simulations. HTML and JavaScript are used to enable a user to explore these modules online in a web browser. Numerous multiple choice questions, links and references for advanced study are

  9. 3D reconstruction based on CT image and its application

    NASA Astrophysics Data System (ADS)

    Zhang, Jianxun; Zhang, Mingmin

    2004-03-01

    Reconstitute the 3-D model of the liver and its internal piping system and simulation of the liver surgical operation can increase the accurate and security of the liver surgical operation, attain a purpose for the biggest limit decrease surgical operation wound, shortening surgical operation time, increasing surgical operation succeeding rate, reducing medical treatment expenses and promoting patient recovering from illness. This text expatiated technology and method that the author constitutes 3-D the model of the liver and its internal piping system and simulation of the liver surgical operation according to the images of CT. The direct volume rendering method establishes 3D the model of the liver. Under the environment of OPENGL adopt method of space point rendering to display liver's internal piping system and simulation of the liver surgical operation. Finally, we adopt the wavelet transform method compressed the medical image data.

  10. Pitfalls in PET/CT imaging

    NASA Astrophysics Data System (ADS)

    Rondogianni, Ph; Papathanasiou, N.; Giannopoulou, Ch

    2011-09-01

    PET with 2-[fluorine 18] fluoro-2-deoxy-d-glucose (FDG), has been a clinical tool for the evaluation of various cancers providing valuable metabolic information clinically helpful in the diagnosis, initial staging, therapy monitoring and restaging. However, FDG is not specific for neoplastic processes. Unless anatomic correlation is available to delineate normal structures, pathologic sites of FDG accumulation can easily be confused with normal physiological uptake, leading to false-positive or false-negative findings. Coregistration of PET scans (functional and morphologic information) with computed tomographic (CT) scans (anatomic information) using a combined PET-CT scanner improves the overall sensitivity and specificity of information provided by PET or CT alone. In this paper, we discuss the probable causes of false negative images and pitfalls due to technical reasons, inflammatory processes or benign lesions as well as the utility of PET-CT in differentiating malignant from inflammatory and benign processes, since in some cases such differentiation cannot be made, with certainty, using FDG PET alone.

  11. MR to CT registration of brains using image synthesis

    NASA Astrophysics Data System (ADS)

    Roy, Snehashis; Carass, Aaron; Jog, Amod; Prince, Jerry L.; Lee, Junghoon

    2014-03-01

    Computed tomography (CT) is the preferred imaging modality for patient dose calculation for radiation therapy. Magnetic resonance (MR) imaging (MRI) is used along with CT to identify brain structures due to its superior soft tissue contrast. Registration of MR and CT is necessary for accurate delineation of the tumor and other structures, and is critical in radiotherapy planning. Mutual information (MI) or its variants are typically used as a similarity metric to register MRI to CT. However, unlike CT, MRI intensity does not have an accepted calibrated intensity scale. Therefore, MI-based MR-CT registration may vary from scan to scan as MI depends on the joint histogram of the images. In this paper, we propose a fully automatic framework for MR-CT registration by synthesizing a synthetic CT image from MRI using a co-registered pair of MR and CT images as an atlas. Patches of the subject MRI are matched to the atlas and the synthetic CT patches are estimated in a probabilistic framework. The synthetic CT is registered to the original CT using a deformable registration and the computed deformation is applied to the MRI. In contrast to most existing methods, we do not need any manual intervention such as picking landmarks or regions of interests. The proposed method was validated on ten brain cancer patient cases, showing 25% improvement in MI and correlation between MR and CT images after registration compared to state-of-the-art registration methods.

  12. Method for transforming CT images for attenuation correction in PET/CT imaging

    SciTech Connect

    Carney, Jonathan P.J.; Townsend, David W.; Rappoport, Vitaliy; Bendriem, Bernard

    2006-04-15

    A tube-voltage-dependent scheme is presented for transforming Hounsfield units (HU) measured by different computed tomography (CT) scanners at different x-ray tube voltages (kVp) to 511 keV linear attenuation values for attenuation correction in positron emission tomography (PET) data reconstruction. A Gammex 467 electron density CT phantom was imaged using a Siemens Sensation 16-slice CT, a Siemens Emotion 6-slice CT, a GE Lightspeed 16-slice CT, a Hitachi CXR 4-slice CT, and a Toshiba Aquilion 16-slice CT at kVp ranging from 80 to 140 kVp. All of these CT scanners are also available in combination with a PET scanner as a PET/CT tomograph. HU obtained for various reference tissue substitutes in the phantom were compared with the known linear attenuation values at 511 keV. The transformation, appropriate for lung, soft tissue, and bone, yields the function 9.6x10{sup -5}{center_dot}(HU+1000) below a threshold of {approx}50 HU and a{center_dot}(HU+1000)+b above the threshold, where a and b are fixed parameters that depend on the kVp setting. The use of the kVp-dependent scaling procedure leads to a significant improvement in reconstructed PET activity levels in phantom measurements, resolving errors of almost 40% otherwise seen for the case of dense bone phantoms at 80 kVp. Results are also presented for patient studies involving multiple CT scans at different kVp settings, which should all lead to the same 511 keV linear attenuation values. A linear fit to values obtained from 140 kVp CT images using the kVp-dependent scaling plotted as a function of the corresponding values obtained from 80 kVp CT images yielded y=1.003x-0.001 with an R{sup 2} value of 0.999, indicating that the same values are obtained to a high degree of accuracy.

  13. [Imaging of rheumatoid arthritis: role of MR imaging and CT].

    PubMed

    Sugimoto, Hideharu

    2013-07-01

    An increasing aggressive therapeutic strategy has attracted growing attention to the potentials of MR imaging in the diagnosis, prognostication, and outcome measure of rheumatoid arthritis (RA). In the diagnosis of RA, skeletal destructions are the key to the diagnosis and assessment of long-term prognosis in RA. Marginal bone erosion is still recognized as an important finding in the 2010 RA criteria, and erosions typical of RA are deemed to have prima facie evidence of RA. MR imaging can detect erosions better than radiolography. In this regard, erosions detected by CT are considered to be reference standard to evaluate diagnostic accuracy of erosion in MR imaging and other imaging modalities. Further, to assess therapeutic effect of therapeutic agents involving the control of bone remodeling, CT may be used to evaluate bone formation and improvement of osteoporosis. PMID:23961666

  14. Computer-aided diagnosis workstation and network system for chest diagnosis based on multislice CT images

    NASA Astrophysics Data System (ADS)

    Satoh, Hitoshi; Niki, Noboru; Mori, Kiyoshi; Eguchi, Kenji; Kaneko, Masahiro; Kakinuma, Ryutarou; Moriyama, Noriyuki; Ohmatsu, Hironobu; Masuda, Hideo; Machida, Suguru

    2007-03-01

    Multislice CT scanner advanced remarkably at the speed at which the chest CT images were acquired for mass screening. Mass screening based on multislice CT images requires a considerable number of images to be read. It is this time-consuming step that makes the use of helical CT for mass screening impractical at present. To overcome this problem, we have provided diagnostic assistance methods to medical screening specialists by developing a lung cancer screening algorithm that automatically detects suspected lung cancers in helical CT images and a coronary artery calcification screening algorithm that automatically detects suspected coronary artery calcification. Moreover, we have provided diagnostic assistance methods to medical screening specialists by using a lung cancer screening algorithm built into mobile helical CT scanner for the lung cancer mass screening done in the region without the hospital. We also have developed electronic medical recording system and prototype internet system for the community health in two or more regions by using the Virtual Private Network router and Biometric fingerprint authentication system and Biometric face authentication system for safety of medical information. Based on these diagnostic assistance methods, we have now developed a new computer-aided workstation and database that can display suspected lesions three-dimensionally in a short time. This paper describes basic studies that have been conducted to evaluate this new system.

  15. Advantages of semiconductor CZT for medical imaging

    NASA Astrophysics Data System (ADS)

    Wagenaar, Douglas J.; Parnham, Kevin; Sundal, Bjorn; Maehlum, Gunnar; Chowdhury, Samir; Meier, Dirk; Vandehei, Thor; Szawlowski, Marek; Patt, Bradley E.

    2007-09-01

    Cadmium zinc telluride (CdZnTe, or CZT) is a room-temperature semiconductor radiation detector that has been developed in recent years for a variety of applications. CZT has been investigated for many potential uses in medical imaging, especially in the field of single photon emission computed tomography (SPECT). CZT can also be used in positron emission tomography (PET) as well as photon-counting and integration-mode x-ray radiography and computed tomography (CT). The principal advantages of CZT are 1) direct conversion of x-ray or gamma-ray energy into electron-hole pairs; 2) energy resolution; 3) high spatial resolution and hence high space-bandwidth product; 4) room temperature operation, stable performance, high density, and small volume; 5) depth-of-interaction (DOI) available through signal processing. These advantages will be described in detail with examples from our own CZT systems. The ability to operate at room temperature, combined with DOI and very small pixels, make the use of multiple, stationary CZT "mini-gamma cameras" a realistic alternative to today's large Anger-type cameras that require motion to obtain tomographic sampling. The compatibility of CZT with Magnetic Resonance Imaging (MRI)-fields is demonstrated for a new type of multi-modality medical imaging, namely SPECT/MRI. For pre-clinical (i.e., laboratory animal) imaging, the advantages of CZT lie in spatial and energy resolution, small volume, automated quality control, and the potential for DOI for parallax removal in pinhole imaging. For clinical imaging, the imaging of radiographically dense breasts with CZT enables scatter rejection and hence improved contrast. Examples of clinical breast images with a dual-head CZT system are shown.

  16. Progress in noninvasive coronary artery imaging using multislice CT

    PubMed Central

    Meijs, M.F.L.; de Vos, A.M.; Rutten, A.; Prokop, M.; Cramer, M.J.M.; Doevendans, P.A.F.M.

    2005-01-01

    Conventional coronary angiography (CAG) has been the reference standard for the assessment of coronary artery disease since its introduction in 1958. However, several studies have shown that diagnostic CAG has an average morbidity of 2% and a mortality of approximately 0.1%. In the last decade, progress in medical imaging has opened the way to noninvasive assessment of the coronary arteries at lower cost and risk. Of the different modalities, multislice CT (MSCT) has made the biggest step forward. At the 2005 European Congress of Radiology (ECR), experiences with the latest developments in noninvasive coronary artery imaging were reported. This report summarises the advances in the use of MSCT in coronary stenosis detection, emergency decision-making, plaque imaging, and the analysis of cardiac function and late enhancement. Also, attention is paid to new strategies to reduce MSCT-related radiation exposure. PMID:25696518

  17. Sci—Thur PM: Imaging — 06: Canada's National Computed Tomography (CT) Survey

    SciTech Connect

    Wardlaw, GM; Martel, N; Blackler, W; Asselin, J-F

    2014-08-15

    The value of computed tomography (CT) in medical imaging is reflected in its' increased use and availability since the early 1990's; however, given CT's relatively larger exposures (vs. planar x-ray) greater care must be taken to ensure that CT procedures are optimised in terms of providing the smallest dose possible while maintaining sufficient diagnostic image quality. The development of CT Diagnostic Reference Levels (DRLs) supports this process. DRLs have been suggested/supported by international/national bodies since the early 1990's and widely adopted elsewhere, but not on a national basis in Canada. Essentially, CT DRLs provide guidance on what is considered good practice for common CT exams, but require a representative sample of CT examination data to make any recommendations. Canada's National CT Survey project, in collaboration with provincial/territorial authorities, has collected a large national sample of CT practice data for 7 common examinations (with associated clinical indications) of both adult and pediatric patients. Following completion of data entry into a common database, a survey summary report and recommendations will be made on CT DRLs from this data. It is hoped that these can then be used by local regions to promote CT practice optimisation and support any dose reduction initiatives.

  18. Rodent brain imaging with SPECT/CT

    SciTech Connect

    Seo, Youngho; Gao, D.-W.; Hasegawa, Bruce H.; Dae, Michael W.; Franc, Benjamin L.

    2007-04-15

    We evaluated methods of imaging rat models of stroke in vivo using a single photon emission computed tomography (SPECT) system dedicated to small animal imaging (X-SPECT{sup TM}, Gamma Medica-Ideas, Northridge, CA). An animal model of ischemic stroke was developed for in vivo SPECT/CT imaging using the middle cerebral artery occlusion (MCAO) technique. The presence of cerebral ischemia was verified in ex vivo studies using triphenyltetrazolium chloride (TTC) staining. In vivo radionuclide imaging of cerebral blood flow was performed in rats following MCAO using dynamic planar imaging of {sup 99m}Tc-exametazime with parallel hole collimation. This was followed immediately by in vivo radionuclide imaging of cerebral blood flow with {sup 99m}Tc-exametazime in the same animals using 1-mm pinhole SPECT. Correlated computed tomography imaging was performed to localize radiopharmaceutical uptake. The animals were allowed to recover and ex vivo autoradiography was performed with separate administration of {sup 99m}Tc-exametazime. Time activity curve of {sup 99m}Tc-exametazime showed that the radiopharmaceutical uptake could be maintained for over 9 min. The activity would be expected to be relatively stable for a much longer period, although the data were only obtained for 9 min. TTC staining revealed sizable infarcts by visual observation of inexistence of TTC stain in infracted tissues of MCAO rat brains. In vivo SPECT imaging showed cerebral blood flow deficit in the MCAO model, and the in vivo imaging result was confirmed with ex vivo autoradiography. We have demonstrated a capability of imaging regions of cerebral blood flow deficit in MCAO rat brains in vivo using a pinhole SPECT dedicated to small animal imaging.

  19. Image quality in CT: From physical measurements to model observers.

    PubMed

    Verdun, F R; Racine, D; Ott, J G; Tapiovaara, M J; Toroi, P; Bochud, F O; Veldkamp, W J H; Schegerer, A; Bouwman, R W; Giron, I Hernandez; Marshall, N W; Edyvean, S

    2015-12-01

    Evaluation of image quality (IQ) in Computed Tomography (CT) is important to ensure that diagnostic questions are correctly answered, whilst keeping radiation dose to the patient as low as is reasonably possible. The assessment of individual aspects of IQ is already a key component of routine quality control of medical x-ray devices. These values together with standard dose indicators can be used to give rise to 'figures of merit' (FOM) to characterise the dose efficiency of the CT scanners operating in certain modes. The demand for clinically relevant IQ characterisation has naturally increased with the development of CT technology (detectors efficiency, image reconstruction and processing), resulting in the adaptation and evolution of assessment methods. The purpose of this review is to present the spectrum of various methods that have been used to characterise image quality in CT: from objective measurements of physical parameters to clinically task-based approaches (i.e. model observer (MO) approach) including pure human observer approach. When combined together with a dose indicator, a generalised dose efficiency index can be explored in a framework of system and patient dose optimisation. We will focus on the IQ methodologies that are required for dealing with standard reconstruction, but also for iterative reconstruction algorithms. With this concept the previously used FOM will be presented with a proposal to update them in order to make them relevant and up to date with technological progress. The MO that objectively assesses IQ for clinically relevant tasks represents the most promising method in terms of radiologist sensitivity performance and therefore of most relevance in the clinical environment. PMID:26459319

  20. Fusion of PET and CT images using wavelet transform.

    PubMed

    Shalchian, Bahareh; Rajabi, Hossein; Soltanian-zadeh, Hamid

    2009-01-01

    While information about anatomy is available in CT images, information about physiology and metabolism is available in PET images. To integrate both information, the two images are fused. Image fusion methods include simple methods like pixel averaging and sophisticated methods like wavelet transformation. An advantage of using wavelet transformation is that it preserves significant parts of each image. After creating lesions of 10, 8, 6 mm in a NURBS (non-uniform rational B-splines) based cardiac torso (NCAT) phantom, PET images were simulated using SimSET simulator. Attenuation maps of the activity phantom were used as CT images. Each of the PET and CT images was divided into an approximation image and three detailed images by the wavelet transform. The corresponding transformed images generated from the PET and CT images were fused in nine different ways to generate composite images, which were compared to the original images. The basis of comparison is the lesion-to-tissue contrast in the fused image in comparison to the lesion-to-tissue contrast in the original PET and CT images. Our results showed that except for one method, the lesion-to-tissue contrast in the fused image was higher than that of the CT images. In the first six methods, the lesion-to-tissue contrast in the fused image was less than the contrast, in the PET image. In the other three methods, the contrast in the fused image was higher than in the PET image. This was true in cases of 10, 8, 6 mm lesions. In conclusion, we have show that the approximation image produced a better ultimate image and that the lesion-to-tissue contrast in the fused image was also better than that of the original PET and CT images. This is because the approximation image is comprised of fundamental information of the signal (low frequency) that directly affects the image contrast. PMID:19936335

  1. Medical image fusion based on non-negative matrix factorization

    NASA Astrophysics Data System (ADS)

    Zhang, Daoming; Zhang, Xianda

    2009-10-01

    Medical image fusion is a process of obtaining a new composite image from two or more source images which are from different modalities. In this paper, we proposed a novel medical image fusion scheme based on the non-negative matrix factorization (NMF) algorithm, the only resulted basis image is just the fused image. Since the CT and MRI images have a lot of pixels which are zeros, the NMF algorithm can not be employed directly. To overcome this difficulty, we first add a positive bias to the original data matrix and remove the bias from the resulted fusion image after the NMF procedure. The experiment results show that the proposed approach outperforms the existing wavelet-based methods and Laplacian pyramid-based methods.

  2. Contextual medical-image viewer

    NASA Astrophysics Data System (ADS)

    Moreno, Ramon A.; Furuie, Sergio S.

    2004-04-01

    One of the greatest difficulties of dealing with medical images is their distinct characteristics, in terms of generation process and noise that requires different forms of treatment for visualization and processing. Besides that, medical images are only a compounding part of the patient"s history, which should be accessible for the user in an understandable way. Other factors that can be used to enhance the user capability and experience are: the computational power of the client machine; available knowledge about the case; if the access is local or remote and what kind of user is accessing the system (physician, nurse, administrator, etc...). These information compose the context of an application and should define its behavior during execution time. In this article, we present the architecture of a viewer that takes into account the contextual information that is present at the moment of execution. We also present a viewer of X-Ray Angiographic images that uses contextual information about the client's hardware and the kind of user to, if necessary, reduce the image size and hide demographic information of the patient. The proposed architecture is extensible, allowing the inclusion of new tools and viewers, being adaptive along time to the evolution of the medical systems.

  3. Multimodality and nanoparticles in medical imaging

    PubMed Central

    Huang, Wen-Yen; Davis, Jason J.

    2015-01-01

    A number of medical imaging techniques are used heavily in the provision of spatially resolved information on disease and physiological status and accordingly play a critical role in clinical diagnostics and subsequent treatment. Though, for most imaging modes, contrast is potentially enhanced through the use of contrast agents or improved hardware or imaging protocols, no single methodology provides, in isolation, a detailed mapping of anatomy, disease markers or physiological status. In recent years, the concept of complementing the strengths of one imaging modality with those of another has come to the fore and been further bolstered by the development of fused instruments such as PET/CT and PET/MRI stations. Coupled with the continual development in imaging hardware has been a surge in reports of contrast agents bearing multiple functionality, potentially providing not only a powerful and highly sensitised means of co-localising physiological/disease status and anatomy, but also the tracking and delineation of multiple markers and indeed subsequent or simultaneous highly localized therapy (“theragnostics”). PMID:21409202

  4. Neural network and its application to CT imaging

    SciTech Connect

    Nikravesh, M.; Kovscek, A.R.; Patzek, T.W.

    1997-02-01

    We present an integrated approach to imaging the progress of air displacement by spontaneous imbibition of oil into sandstone. We combine Computerized Tomography (CT) scanning and neural network image processing. The main aspects of our approach are (I) visualization of the distribution of oil and air saturation by CT, (II) interpretation of CT scans using neural networks, and (III) reconstruction of 3-D images of oil saturation from the CT scans with a neural network model. Excellent agreement between the actual images and the neural network predictions is found.

  5. PET/CT imaging in neuroblastoma.

    PubMed

    Piccardo, A; Lopci, E; Conte, M; Foppiani, L; Garaventa, A; Cabria, M; Villavecchia, G; Fanti, S; Cistaro, A

    2013-03-01

    123Iodine-metaiodobenzylguanidine (123I-MIBG) scintigraphy is currently the tracer of choice for neuroblastoma (NB). It has high diagnostic accuracy and prognostic value for the assessment of patients after chemotherapy. A positive 123I-MIBG scan is also used for the basis of targeted radionuclide therapy with 131I-MIBG. I-123 MIBG scan however has some limitations which should be taken into account. Moreover the reasons for false negative MIBG results have not been entirely elucidated. Meticulous correlation with radiological examinations and recognition of the normal distribution pattern of 123I-MIBG in children is vital to obtain optimal results. With its technical superiorities, positron emission tomography/computed tomography (PET/CT) can be successfully introduced into the diagnostic workup of NB. Different PET tracers have been offered for imaging in patients with NB, and the efficacy of this modality has been compared with that of 123I-MIBG scan. Our review aims to analyze the present role of PET/CT imaging and radiopharmaceuticals in NB. PMID:23474633

  6. Upright cone beam CT imaging using the onboard imager

    SciTech Connect

    Fave, Xenia Martin, Rachael; Yang, Jinzhong; Balter, Peter; Court, Laurence; Carvalho, Luis; Pan, Tinsu

    2014-06-15

    Purpose: Many patients could benefit from being treated in an upright position. The objectives of this study were to determine whether cone beam computed tomography (CBCT) could be used to acquire upright images for treatment planning and to demonstrate whether reconstruction of upright images maintained accurate geometry and Hounsfield units (HUs). Methods: A TrueBeam linac was programmed in developer mode to take upright CBCT images. The gantry head was positioned at 0°, and the couch was rotated to 270°. The x-ray source and detector arms were extended to their lateral positions. The x-ray source and gantry remained stationary as fluoroscopic projections were taken and the couch was rotated from 270° to 90°. The x-ray tube current was normalized to deposit the same dose (measured using a calibrated Farmer ion chamber) as that received during a clinical helical CT scan to the center of a cylindrical, polyethylene phantom. To extend the field of view, two couch rotation scans were taken with the detector offset 15 cm superiorly and then 15 cm inferiorly. The images from these two scans were stitched together before reconstruction. Upright reconstructions were compared to reconstructions from simulation CT scans of the same phantoms. Two methods were investigated for correcting the HUs, including direct calibration and mapping the values from a simulation CT. Results: Overall geometry, spatial linearity, and high contrast resolution were maintained in upright reconstructions. Some artifacts were created and HU accuracy was compromised; however, these limitations could be removed by mapping the HUs from a simulation CT to the upright reconstruction for treatment planning. Conclusions: The feasibility of using the TrueBeam linac to take upright CBCT images was demonstrated. This technique is straightforward to implement and could be of enormous benefit to patients with thoracic tumors or those who find a supine position difficult to endure.

  7. An approach for quantitative image quality analysis for CT

    NASA Astrophysics Data System (ADS)

    Rahimi, Amir; Cochran, Joe; Mooney, Doug; Regensburger, Joe

    2016-03-01

    An objective and standardized approach to assess image quality of Compute Tomography (CT) systems is required in a wide variety of imaging processes to identify CT systems appropriate for a given application. We present an overview of the framework we have developed to help standardize and to objectively assess CT image quality for different models of CT scanners used for security applications. Within this framework, we have developed methods to quantitatively measure metrics that should correlate with feature identification, detection accuracy and precision, and image registration capabilities of CT machines and to identify strengths and weaknesses in different CT imaging technologies in transportation security. To that end we have designed, developed and constructed phantoms that allow for systematic and repeatable measurements of roughly 88 image quality metrics, representing modulation transfer function, noise equivalent quanta, noise power spectra, slice sensitivity profiles, streak artifacts, CT number uniformity, CT number consistency, object length accuracy, CT number path length consistency, and object registration. Furthermore, we have developed a sophisticated MATLAB based image analysis tool kit to analyze CT generated images of phantoms and report these metrics in a format that is standardized across the considered models of CT scanners, allowing for comparative image quality analysis within a CT model or between different CT models. In addition, we have developed a modified sparse principal component analysis (SPCA) method to generate a modified set of PCA components as compared to the standard principal component analysis (PCA) with sparse loadings in conjunction with Hotelling T2 statistical analysis method to compare, qualify, and detect faults in the tested systems.

  8. Low dose CT image restoration using a database of image patches

    NASA Astrophysics Data System (ADS)

    Ha, Sungsoo; Mueller, Klaus

    2015-01-01

    Reducing the radiation dose in CT imaging has become an active research topic and many solutions have been proposed to remove the significant noise and streak artifacts in the reconstructed images. Most of these methods operate within the domain of the image that is subject to restoration. This, however, poses limitations on the extent of filtering possible. We advocate to take into consideration the vast body of external knowledge that exists in the domain of already acquired medical CT images, since after all, this is what radiologists do when they examine these low quality images. We can incorporate this knowledge by creating a database of prior scans, either of the same patient or a diverse corpus of different patients, to assist in the restoration process. Our paper follows up on our previous work that used a database of images. Using images, however, is challenging since it requires tedious and error prone registration and alignment. Our new method eliminates these problems by storing a diverse set of small image patches in conjunction with a localized similarity matching scheme. We also empirically show that it is sufficient to store these patches without anatomical tags since their statistics are sufficiently strong to yield good similarity matches from the database and as a direct effect, produce image restorations of high quality. A final experiment demonstrates that our global database approach can recover image features that are difficult to preserve with conventional denoising approaches.

  9. Digital diagnosis of medical images

    NASA Astrophysics Data System (ADS)

    Heinonen, Tomi; Kuismin, Raimo; Jormalainen, Raimo; Dastidar, Prasun; Frey, Harry; Eskola, Hannu

    2001-08-01

    The popularity of digital imaging devices and PACS installations has increased during the last years. Still, images are analyzed and diagnosed using conventional techniques. Our research group begun to study the requirements for digital image diagnostic methods to be applied together with PACS systems. The research was focused on various image analysis procedures (e.g., segmentation, volumetry, 3D visualization, image fusion, anatomic atlas, etc.) that could be useful in medical diagnosis. We have developed Image Analysis software (www.medimag.net) to enable several image-processing applications in medical diagnosis, such as volumetry, multimodal visualization, and 3D visualizations. We have also developed a commercial scalable image archive system (ActaServer, supports DICOM) based on component technology (www.acta.fi), and several telemedicine applications. All the software and systems operate in NT environment and are in clinical use in several hospitals. The analysis software have been applied in clinical work and utilized in numerous patient cases (500 patients). This method has been used in the diagnosis, therapy and follow-up in various diseases of the central nervous system (CNS), respiratory system (RS) and human reproductive system (HRS). In many of these diseases e.g. Systemic Lupus Erythematosus (CNS), nasal airways diseases (RS) and ovarian tumors (HRS), these methods have been used for the first time in clinical work. According to our results, digital diagnosis improves diagnostic capabilities, and together with PACS installations it will become standard tool during the next decade by enabling more accurate diagnosis and patient follow-up.

  10. Medical Imaging of Hyperpolarized Gases

    NASA Astrophysics Data System (ADS)

    Miller, G. Wilson

    2009-08-01

    Since the introduction of hyperpolarized 3He and 129Xe as gaseous MRI contrast agents more than a decade ago, a rich variety of imaging techniques and medical applications have been developed. Magnetic resonance imaging of the inhaled gas depicts ventilated lung airspaces with unprecedented detail, and allows one to track airflow and pulmonary mechanics during respiration. Information about lung structure and function can also be obtained using the physical properties of the gas, including spin relaxation in the presence of oxygen, restricted diffusion inside the alveolar airspaces, and the NMR frequency shift of xenon dissolved in blood and tissue.

  11. Preliminary experience on the implementation of computed tomography (CT)-based image guided brachytherapy (IGBT) of cervical cancer using high-dose-rate (HDR) Cobalt-60 source in University of Malaya Medical Centre (UMMC)

    NASA Astrophysics Data System (ADS)

    Jamalludin, Z.; Min, U. N.; Ishak, W. Z. Wan; Malik, R. Abdul

    2016-03-01

    This study presents our preliminary work of the computed tomography (CT) image guided brachytherapy (IGBT) implementation on cervical cancer patients. We developed a protocol in which patients undergo two Magnetic Resonance Imaging (MRI) examinations; a) prior to external beam radiotherapy (EBRT) and b) prior to intra-cavitary brachytherapy for tumour identification and delineation during IGBT planning and dosimetry. For each fraction, patients were simulated using CT simulator and images were transferred to the treatment planning system. The HR-CTV, IR-CTV, bladder and rectum were delineated on CT-based contouring for cervical cancer. Plans were optimised to achieve HR-CTV and IR-CTV dose (D90) of total EQD2 80Gy and 60Gy respectively, while limiting the minimum dose to the most irradiated 2cm3 volume (D2cc) of bladder and rectum to total EQD2 90Gy and 75Gy respectively. Data from seven insertions were analysed by comparing the volume-based with traditional point- based doses. Based on our data, there were differences between volume and point doses of HR- CTV, bladder and rectum organs. As the number of patients having the CT-based IGBT increases from day to day in our centre, it is expected that the treatment and dosimetry accuracy will be improved with the implementation.

  12. Medical Imaging In An Object Oriented Environment

    NASA Astrophysics Data System (ADS)

    Geist, Daniel; Vannier, Michael W.

    1988-06-01

    A workstation has been developed to evaluate computed tomographic (CT) image data in 2 and 3 dimensions. The workstation consists of an independent image display station (Independent Viewing and Analysis Station or WAS, International Imaging Systems, Inc., Milpitas, Calif.) and a VAX host computer. The WAS has 1024 X 1024 X 24 bits of image memory plus 4 bits of graphics overlay. An independent VLSI graphics processor and 1024 X 1024 X 4 bit graphics memory, independent of the image memory, are included in the self-contained WAS unit. A local microprocessor host (Motorola 68000 microprocessor) controls the IVAS from directives obtained through a direct memory access channel to the VAX host. This facilitated the creation of an object oriented software enviroment for the IVAS under control of a VAX host program written in the C language. The workstation created has an interactive user interface consisting of a mouse and pull-down menus. The workstation enables loading multiple images, typically 256 x 256 or 512 x 512, into the 1024 X 1024 frame buffer. Once loaded, the images can be manipulated by applying gray scale transforms, editing them and performing 3-D reconstructions from serial sections. Algorithms for three dimensional (3-D) reconstructions were implemented in the VAX/VMS host computer environment and are available on the workstation through special menu functions for handling these reconstructions. The functions interactively combine depth and gradient shading of surfaces to suit specific applications in craniofacial surgical planning or orthopedics. This workstation is user friendly and is very easy to handle. A workstation of this type may become a popular tool for physicians and surgeons in evalution of medical images.

  13. Soft tissue imaging with photon counting spectroscopic CT

    NASA Astrophysics Data System (ADS)

    Shikhaliev, Polad M.

    2015-03-01

    The purpose of this work was experimental investigation of photon counting spectroscopic CT (PCS-CT) imaging of anatomical soft tissue with clinically relevant size. The imaging experiments were performed using a spectroscopic CT system based on CdZnTe photon counting detector with two rows of pixels, 256 pixels in each row, 1  ×  1 mm2 pixel size, and 25.6 cm detector length. The detector could split the x-ray energy spectrum to 5 regions (energy bins), and acquire 5 multi-energy (spectroscopic) CT images in a single CT scan. A sample of round shaped anatomical soft tissue of 14 cm diameter including lean and fat was used for imaging. To avoid the negative effect of anatomical noise on quantitative analysis, a spectroscopic CT phantom with tissue equivalent solid materials was used. The images were acquired at 60, 90, and 120 kVp tube voltages, and spectroscopic image series were acquired with 3 and 5 energy bins. Spectroscopic CT numbers were introduced and used to evaluate an energy selective image series. The anatomical soft tissue with 14 cm diameter was visualized with good quality and without substantial artifacts by the photon counting spectroscopic CT system. The effects of the energy bin crosstalk on spectroscopic CT numbers were quantified and analyzed. The single and double slice PCS-CT images were acquired and compared. Several new findings were observed, including the effect of soft tissue non-uniformity on image artifacts, unique status of highest energy bin, and material dependent visualization in spectroscopic image series. Fat-lean decomposition was performed using dual energy subtraction and threshold segmentation methods, and compared. Using K-edge filtered x-rays improved fat-lean decomposition as compared to conventional x-rays. Several new and important aspects of the PCS-CT were investigated. These include imaging soft tissue with clinically relevant size, single- and double-slice PCS-CT imaging, using spectroscopic CT

  14. Soft tissue imaging with photon counting spectroscopic CT.

    PubMed

    Shikhaliev, Polad M

    2015-03-21

    The purpose of this work was experimental investigation of photon counting spectroscopic CT (PCS-CT) imaging of anatomical soft tissue with clinically relevant size. The imaging experiments were performed using a spectroscopic CT system based on CdZnTe photon counting detector with two rows of pixels, 256 pixels in each row, 1  ×  1 mm(2) pixel size, and 25.6 cm detector length. The detector could split the x-ray energy spectrum to 5 regions (energy bins), and acquire 5 multi-energy (spectroscopic) CT images in a single CT scan. A sample of round shaped anatomical soft tissue of 14 cm diameter including lean and fat was used for imaging. To avoid the negative effect of anatomical noise on quantitative analysis, a spectroscopic CT phantom with tissue equivalent solid materials was used. The images were acquired at 60, 90, and 120 kVp tube voltages, and spectroscopic image series were acquired with 3 and 5 energy bins. Spectroscopic CT numbers were introduced and used to evaluate an energy selective image series. The anatomical soft tissue with 14 cm diameter was visualized with good quality and without substantial artifacts by the photon counting spectroscopic CT system. The effects of the energy bin crosstalk on spectroscopic CT numbers were quantified and analyzed. The single and double slice PCS-CT images were acquired and compared. Several new findings were observed, including the effect of soft tissue non-uniformity on image artifacts, unique status of highest energy bin, and material dependent visualization in spectroscopic image series. Fat-lean decomposition was performed using dual energy subtraction and threshold segmentation methods, and compared. Using K-edge filtered x-rays improved fat-lean decomposition as compared to conventional x-rays. Several new and important aspects of the PCS-CT were investigated. These include imaging soft tissue with clinically relevant size, single- and double-slice PCS-CT imaging, using spectroscopic CT

  15. Automated vertebra identification in CT images

    NASA Astrophysics Data System (ADS)

    Ehm, Matthias; Klinder, Tobias; Kneser, Reinhard; Lorenz, Cristian

    2009-02-01

    In this paper, we describe and compare methods for automatically identifying individual vertebrae in arbitrary CT images. The identification is an essential precondition for a subsequent model-based segmentation, which is used in a wide field of orthopedic, neurological, and oncological applications, e.g., spinal biopsies or the insertion of pedicle screws. Since adjacent vertebrae show similar characteristics, an automated labeling of the spine column is a very challenging task, especially if no surrounding reference structures can be taken into account. Furthermore, vertebra identification is complicated due to the fact that many images are bounded to a very limited field of view and may contain only few vertebrae. We propose and evaluate two methods for automatically labeling the spine column by evaluating similarities between given models and vertebral objects. In one method, object boundary information is taken into account by applying a Generalized Hough Transform (GHT) for each vertebral object. In the other method, appearance models containing mean gray value information are registered to each vertebral object using cross and local correlation as similarity measures for the optimization function. The GHT is advantageous in terms of computational performance but cuts back concerning the identification rate. A correct labeling of the vertebral column has been successfully performed on 93% of the test set consisting of 63 disparate input images using rigid image registration with local correlation as similarity measure.

  16. X-ray detectors in medical imaging

    NASA Astrophysics Data System (ADS)

    Spahn, Martin

    2013-12-01

    Healthcare systems are subject to continuous adaptation, following trends such as the change of demographic structures, the rise of life-style related and chronic diseases, and the need for efficient and outcome-oriented procedures. This also influences the design of new imaging systems as well as their components. The applications of X-ray imaging in the medical field are manifold and have led to dedicated modalities supporting specific imaging requirements, for example in computed tomography (CT), radiography, angiography, surgery or mammography, delivering projection or volumetric imaging data. Depending on the clinical needs, some X-ray systems enable diagnostic imaging while others support interventional procedures. X-ray detector design requirements for the different medical applications can vary strongly with respect to size and shape, spatial resolution, frame rates and X-ray flux, among others. Today, integrating X-ray detectors are in common use. They are predominantly based on scintillators (e.g. CsI or Gd2O2S) and arrays of photodiodes made from crystalline silicon (Si) or amorphous silicon (a-Si) or they employ semiconductors (e.g. Se) with active a-Si readout matrices. Ongoing and future developments of X-ray detectors will include optimization of current state-of-the-art integrating detectors in terms of performance and cost, will enable the usage of large size CMOS-based detectors, and may facilitate photon counting techniques with the potential to further enhance performance characteristics and foster the prospect of new clinical applications.

  17. Archimedes, an archive of medical images.

    PubMed

    Tahmoush, Dave; Samet, Hanan

    2006-01-01

    We present a medical image and medical record database for the storage, research, transmission, and evaluation of medical images. Medical images from any source that supports the DICOM standard can be stored and accessed, as well as associated analysis and annotations. Retrieval is based on patient info, date, doctor's annotations, features in the images, or a spatial combination. This database supports the secure transmission of sensitive data for tele-medicine and follows all HIPPA regulations. PMID:17238733

  18. Medical imaging, PACS, and imaging informatics: retrospective.

    PubMed

    Huang, H K

    2014-01-01

    Historical reviews of PACS (picture archiving and communication system) and imaging informatics development from different points of view have been published in the past (Huang in Euro J Radiol 78:163-176, 2011; Lemke in Euro J Radiol 78:177-183, 2011; Inamura and Jong in Euro J Radiol 78:184-189, 2011). This retrospective attempts to look at the topic from a different angle by identifying certain basic medical imaging inventions in the 1960s and 1970s which had conceptually defined basic components of PACS guiding its course of development in the 1980s and 1990s, as well as subsequent imaging informatics research in the 2000s. In medical imaging, the emphasis was on the innovations at Georgetown University in Washington, DC, in the 1960s and 1970s. During the 1980s and 1990s, research and training support from US government agencies and public and private medical imaging manufacturers became available for training of young talents in biomedical physics and for developing the key components required for PACS development. In the 2000s, computer hardware and software as well as communication networks advanced by leaps and bounds, opening the door for medical imaging informatics to flourish. Because many key components required for the PACS operation were developed by the UCLA PACS Team and its collaborative partners in the 1980s, this presentation is centered on that aspect. During this period, substantial collaborative research efforts by many individual teams in the US and in Japan were highlighted. Credits are due particularly to the Pattern Recognition Laboratory at Georgetown University, and the computed radiography (CR) development at the Fuji Electric Corp. in collaboration with Stanford University in the 1970s; the Image Processing Laboratory at UCLA in the 1980s-1990s; as well as the early PACS development at the Hokkaido University, Sapporo, Japan, in the late 1970s, and film scanner and digital radiography developed by Konishiroku Photo Ind. Co. Ltd

  19. Automatic organ segmentation on torso CT images by using content-based image retrieval

    NASA Astrophysics Data System (ADS)

    Zhou, Xiangrong; Watanabe, Atsuto; Zhou, Xinxin; Hara, Takeshi; Yokoyama, Ryujiro; Kanematsu, Masayuki; Fujita, Hiroshi

    2012-02-01

    This paper presents a fast and robust segmentation scheme that automatically identifies and extracts a massive-organ region on torso CT images. In contrast to the conventional algorithms that are designed empirically for segmenting a specific organ based on traditional image processing techniques, the proposed scheme uses a fully data-driven approach to accomplish a universal solution for segmenting the different massive-organ regions on CT images. Our scheme includes three processing steps: machine-learning-based organ localization, content-based image (reference) retrieval, and atlas-based organ segmentation techniques. We applied this scheme to automatic segmentations of heart, liver, spleen, left and right kidney regions on non-contrast CT images respectively, which are still difficult tasks for traditional segmentation algorithms. The segmentation results of these organs are compared with the ground truth that manually identified by a medical expert. The Jaccard similarity coefficient between the ground truth and automated segmentation result centered on 67% for heart, 81% for liver, 78% for spleen, 75% for left kidney, and 77% for right kidney. The usefulness of our proposed scheme was confirmed.

  20. Multi-gamma-source CT imaging system: a feasibility study with the Poisson noise

    NASA Astrophysics Data System (ADS)

    Wi, Sunhee; Cho, Seungryong

    2016-03-01

    This study was performed to test the feasibility of multi-gamma-source CT imaging system. Gamma-source CT employs radioisotopes that emit monochromatic energy gamma-rays. The advantages of gamma-source CT include its immunity to beam hardening artifacts, its capacity of quantitative CT imaging, and its higher performance in low contrast imaging compared to the conventional x-ray CT. Radioisotope should be shielded by use of a pin-hole collimator so as to make a fine focal spot. Due to its low gamma-ray flux in general, the reconstructed image from a single gamma-source CT would suffer from high noise in data. To address this problem, we proposed a multi-gamma source CT imaging system and developed an iterative image reconstruction algorithm accordingly in this work. Conventional imaging model assumes a single linear imaging system typically represented by Mf = g. In a multi-gamma-source CT system however, the inversion problem is not any more based on a single linear system since one cannot separate a detector pixel value into multiple ones that are corresponding to each rays from the sources. Instead, the imaging model can be constructed by a set of linear system models each of which assumes an estimated measurement g. Based on this model, the proposed algorithm has a weighting step which distributes each projection data into multiple estimated measurements. We used two gamma sources at various positions and with varying intensities in this numerical study to demonstrate its feasibility. Therefore, the measured projection data(g) is separated into each estimated projection data(g1, g2) in this study. The proposed imaging protocol is believed to contribute to both medical and industrial applications.

  1. Automatic Lumbar Spondylolisthesis Measurement in CT Images.

    PubMed

    Liao, Shu; Zhan, Yiqiang; Dong, Zhongxing; Yan, Ruyi; Gong, Liyan; Zhou, Xiang Sean; Salganicoff, Marcos; Fei, Jun

    2016-07-01

    Lumbar spondylolisthesis is one of the most common spinal diseases. It is caused by the anterior shift of a lumbar vertebrae relative to subjacent vertebrae. In current clinical practices, staging of spondylolisthesis is often conducted in a qualitative way. Although meyerding grading opens the door to stage spondylolisthesis in a more quantitative way, it relies on the manual measurement, which is time consuming and irreproducible. Thus, an automatic measurement algorithm becomes desirable for spondylolisthesis diagnosis and staging. However, there are two challenges. 1) Accurate detection of the most anterior and posterior points on the superior and inferior surfaces of each lumbar vertebrae. Due to the small size of the vertebrae, slight errors of detection may lead to significant measurement errors, hence, wrong disease stages. 2) Automatic localize and label each lumbar vertebrae is required to provide the semantic meaning of the measurement. It is difficult since different lumbar vertebraes have high similarity of both shape and image appearance. To resolve these challenges, a new auto measurement framework is proposed with two major contributions: First, a learning based spine labeling method that integrates both the image appearance and spine geometry information is designed to detect lumbar vertebrae. Second, a hierarchical method using both the population information from atlases and domain-specific information in the target image is proposed for most anterior and posterior points positioning. Validated on 258 CT spondylolisthesis patients, our method shows very similar results to manual measurements by radiologists and significantly increases the measurement efficiency. PMID:26849859

  2. Point spread function modeling and image restoration for cone-beam CT

    NASA Astrophysics Data System (ADS)

    Zhang, Hua; Huang, Kui-Dong; Shi, Yi-Kai; Xu, Zhe

    2015-03-01

    X-ray cone-beam computed tomography (CT) has such notable features as high efficiency and precision, and is widely used in the fields of medical imaging and industrial non-destructive testing, but the inherent imaging degradation reduces the quality of CT images. Aimed at the problems of projection image degradation and restoration in cone-beam CT, a point spread function (PSF) modeling method is proposed first. The general PSF model of cone-beam CT is established, and based on it, the PSF under arbitrary scanning conditions can be calculated directly for projection image restoration without the additional measurement, which greatly improved the application convenience of cone-beam CT. Secondly, a projection image restoration algorithm based on pre-filtering and pre-segmentation is proposed, which can make the edge contours in projection images and slice images clearer after restoration, and control the noise in the equivalent level to the original images. Finally, the experiments verified the feasibility and effectiveness of the proposed methods. Supported by National Science and Technology Major Project of the Ministry of Industry and Information Technology of China (2012ZX04007021), Young Scientists Fund of National Natural Science Foundation of China (51105315), Natural Science Basic Research Program of Shaanxi Province of China (2013JM7003) and Northwestern Polytechnical University Foundation for Fundamental Research (JC20120226, 3102014KYJD022)

  3. Cloud computing in medical imaging.

    PubMed

    Kagadis, George C; Kloukinas, Christos; Moore, Kevin; Philbin, Jim; Papadimitroulas, Panagiotis; Alexakos, Christos; Nagy, Paul G; Visvikis, Dimitris; Hendee, William R

    2013-07-01

    Over the past century technology has played a decisive role in defining, driving, and reinventing procedures, devices, and pharmaceuticals in healthcare. Cloud computing has been introduced only recently but is already one of the major topics of discussion in research and clinical settings. The provision of extensive, easily accessible, and reconfigurable resources such as virtual systems, platforms, and applications with low service cost has caught the attention of many researchers and clinicians. Healthcare researchers are moving their efforts to the cloud, because they need adequate resources to process, store, exchange, and use large quantities of medical data. This Vision 20/20 paper addresses major questions related to the applicability of advanced cloud computing in medical imaging. The paper also considers security and ethical issues that accompany cloud computing. PMID:23822402

  4. Carotid plaque characterization using CT and MRI scans for synergistic image analysis

    NASA Astrophysics Data System (ADS)

    Getzin, Matthew; Xu, Yiqin; Rao, Arhant; Madi, Saaussan; Bahadur, Ali; Lennartz, Michelle R.; Wang, Ge

    2014-09-01

    Noninvasive determination of plaque vulnerability has been a holy grail of medical imaging. Despite advances in tomographic technologies , there is currently no effective way to identify vulnerable atherosclerotic plaques with high sensitivity and specificity. Computed tomography (CT) and magnetic resonance imaging (MRI) are widely used, but neither provides sufficient information of plaque properties. Thus, we are motivated to combine CT and MRI imaging to determine if the composite information can better reflect the histological determination of plaque vulnerability. Two human endarterectomy specimens (1 symptomatic carotid and 1 stable femoral) were imaged using Scanco Medical Viva CT40 and Bruker Pharmascan 16cm 7T Horizontal MRI / MRS systems. μCT scans were done at 55 kVp and tube current of 70 mA. Samples underwent RARE-VTR and MSME pulse sequences to measure T1, T2 values, and proton density. The specimens were processed for histology and scored for vulnerability using the American Heart Association criteria. Single modality-based analyses were performed through segmentation of key imaging biomarkers (i.e. calcification and lumen), image registration, measurement of fibrous capsule, and multi-component T1 and T2 decay modeling. Feature differences were analyzed between the unstable and stable controls, symptomatic carotid and femoral plaque, respectively. By building on the techniques used in this study, synergistic CT+MRI analysis may provide a promising solution for plaque characterization in vivo.

  5. Assessment of neural networks training strategies for histomorphometric analysis of synchrotron radiation medical images

    NASA Astrophysics Data System (ADS)

    de Moura Meneses, Anderson Alvarenga; Pinheiro, Christiano Jorge Gomes; Rancoita, Paola; Schaul, Tom; Gambardella, Luca Maria; Schirru, Roberto; Barroso, Regina Cely; de Oliveira, Luís Fernando

    2010-09-01

    Micro-computed tomography (μCT) obtained by synchrotron radiation (SR) enables magnified images with a high space resolution that might be used as a non-invasive and non-destructive technique for the quantitative analysis of medical images, in particular the histomorphometry (HMM) of bony mass. In the preprocessing of such images, conventional operations such as binarization and morphological filtering are used before calculating the stereological parameters related, for example, to the trabecular bone microarchitecture. However, there is no standardization of methods for HMM based on μCT images, especially the ones obtained with SR X-ray. Notwithstanding the several uses of artificial neural networks (ANNs) in medical imaging, their application to the HMM of SR-μCT medical images is still incipient, despite the potential of both techniques. The contribution of this paper is the assessment and comparison of well-known training algorithms as well as the proposal of training strategies (combinations of training algorithms, sub-image kernel and symmetry information) for feed-forward ANNs in the task of bone pixels recognition in SR-μCT medical images. For a quantitative comparison, the results of a cross validation and a statistical analysis of the results for 36 training strategies are presented. The ANNs demonstrated both very low mean square errors in the validation, and good quality segmentation of the image of interest for application to HMM in SR-μCT medical images.

  6. Hybrid µCT-FMT imaging and image analysis

    PubMed Central

    Zafarnia, Sara; Babler, Anne; Jahnen-Dechent, Willi; Lammers, Twan; Lederle, Wiltrud; Kiessling, Fabian

    2015-01-01

    Fluorescence-mediated tomography (FMT) enables longitudinal and quantitative determination of the fluorescence distribution in vivo and can be used to assess the biodistribution of novel probes and to assess disease progression using established molecular probes or reporter genes. The combination with an anatomical modality, e.g., micro computed tomography (µCT), is beneficial for image analysis and for fluorescence reconstruction. We describe a protocol for multimodal µCT-FMT imaging including the image processing steps necessary to extract quantitative measurements. After preparing the mice and performing the imaging, the multimodal data sets are registered. Subsequently, an improved fluorescence reconstruction is performed, which takes into account the shape of the mouse. For quantitative analysis, organ segmentations are generated based on the anatomical data using our interactive segmentation tool. Finally, the biodistribution curves are generated using a batch-processing feature. We show the applicability of the method by assessing the biodistribution of a well-known probe that binds to bones and joints. PMID:26066033

  7. Calibration free beam hardening correction for cardiac CT perfusion imaging

    NASA Astrophysics Data System (ADS)

    Levi, Jacob; Fahmi, Rachid; Eck, Brendan L.; Fares, Anas; Wu, Hao; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    Myocardial perfusion imaging using CT (MPI-CT) and coronary CTA have the potential to make CT an ideal noninvasive gate-keeper for invasive coronary angiography. However, beam hardening artifacts (BHA) prevent accurate blood flow calculation in MPI-CT. BH Correction (BHC) methods require either energy-sensitive CT, not widely available, or typically a calibration-based method. We developed a calibration-free, automatic BHC (ABHC) method suitable for MPI-CT. The algorithm works with any BHC method and iteratively determines model parameters using proposed BHA-specific cost function. In this work, we use the polynomial BHC extended to three materials. The image is segmented into soft tissue, bone, and iodine images, based on mean HU and temporal enhancement. Forward projections of bone and iodine images are obtained, and in each iteration polynomial correction is applied. Corrections are then back projected and combined to obtain the current iteration's BHC image. This process is iterated until cost is minimized. We evaluate the algorithm on simulated and physical phantom images and on preclinical MPI-CT data. The scans were obtained on a prototype spectral detector CT (SDCT) scanner (Philips Healthcare). Mono-energetic reconstructed images were used as the reference. In the simulated phantom, BH streak artifacts were reduced from 12+/-2HU to 1+/-1HU and cupping was reduced by 81%. Similarly, in physical phantom, BH streak artifacts were reduced from 48+/-6HU to 1+/-5HU and cupping was reduced by 86%. In preclinical MPI-CT images, BHA was reduced from 28+/-6 HU to less than 4+/-4HU at peak enhancement. Results suggest that the algorithm can be used to reduce BHA in conventional CT and improve MPI-CT accuracy.

  8. Adjunct processors in embedded medical imaging systems

    NASA Astrophysics Data System (ADS)

    Trepanier, Marc; Goddard, Iain

    2002-05-01

    Adjunct processors have traditionally been used for certain tasks in medical imaging systems. Often based on application-specific integrated circuits (ASICs), these processors formed X-ray image-processing pipelines or constituted the backprojectors in computed tomography (CT) systems. We examine appropriate functions to perform with adjunct processing and draw some conclusions about system design trade-offs. These trade-offs have traditionally focused on the required performance and flexibility of individual system components, with increasing emphasis on time-to-market impact. Typically, front-end processing close to the sensor has the most intensive processing requirements. However, the performance capabilities of each level are dynamic and the system architect must keep abreast of the current capabilities of all options to remain competitive. Designers are searching for the most efficient implementation of their particular system requirements. We cite algorithm characteristics that point to effective solutions by adjunct processors. We have developed a field- programmable gate array (FPGA) adjunct-processor solution for a Cone-Beam Reconstruction (CBR) algorithm that offers significant performance improvements over a general-purpose processor implementation. The same hardware could efficiently perform other image processing functions such as two-dimensional (2D) convolution. The potential performance, price, operating power, and flexibility advantages of an FPGA adjunct processor over an ASIC, DSP or general-purpose processing solutions are compelling.

  9. Despeckling of Medical Ultrasound Images

    PubMed Central

    Michailovich, Oleg V.; Tannenbaum, Allen

    2013-01-01

    Speckle noise is an inherent property of medical ultrasound imaging, and it generally tends to reduce the image resolution and contrast, thereby reducing the diagnostic value of this imaging modality. As a result, speckle noise reduction is an important prerequisite, whenever ultrasound imaging is used for tissue characterization. Among the many methods that have been proposed to perform this task, there exists a class of approaches that use a multiplicative model of speckled image formation and take advantage of the logarithmical transformation in order to convert multiplicative speckle noise into additive noise. The common assumption made in a dominant number of such studies is that the samples of the additive noise are mutually uncorrelated and obey a Gaussian distribution. The present study shows conceptually and experimentally that this assumption is oversimplified and unnatural. Moreover, it may lead to inadequate performance of the speckle reduction methods. The study introduces a simple preprocessing procedure, which modifies the acquired radio-frequency images (without affecting the anatomical information they contain), so that the noise in the log-transformation domain becomes very close in its behavior to a white Gaussian noise. As a result, the preprocessing allows filtering methods based on assuming the noise to be white and Gaussian, to perform in nearly optimal conditions. The study evaluates performances of three different, nonlinear filters—wavelet denoising, total variation filtering, and anisotropic diffusion—and demonstrates that, in all these cases, the proposed preprocessing significantly improves the quality of resultant images. Our numerical tests include a series of computer-simulated and in vivo experiments. PMID:16471433

  10. Despeckling of medical ultrasound images.

    PubMed

    Michailovich, Oleg V; Tannenbaum, Allen

    2006-01-01

    Speckle noise is an inherent property of medical ultrasound imaging, and it generally tends to reduce the image resolution and contrast, thereby reducing the diagnostic value of this imaging modality. As a result, speckle noise reduction is an important prerequisite, whenever ultrasound imaging is used for tissue characterization. Among the many methods that have been proposed to perform this task, there exists a class of approaches that use a multiplicative model of speckled image formation and take advantage of the logarithmical transformation in order to convert multiplicative speckle noise into additive noise. The common assumption made in a dominant number of such studies is that the samples of the additive noise are mutually uncorrelated and obey a Gaussian distribution. The present study shows conceptually and experimentally that this assumption is oversimplified and unnatural. Moreover, it may lead to inadequate performance of the speckle reduction methods. The study introduces a simple preprocessing procedure, which modifies the acquired radio-frequency images (without affecting the anatomical information they contain), so that the noise in the log-transformation domain becomes very close in its behavior to a white Gaussian noise. As a result, the preprocessing allows filtering methods based on assuming the noise to be white and Gaussian, to perform in nearly optimal conditions. The study evaluates performances of three different, nonlinear filters--wavelet denoising, total variation filtering, and anisotropic diffusion--and demonstrates that, in all these cases, the proposed preprocessing significantly improves the quality of resultant images. Our numerical tests include a series of computer-simulated and in vivo experiments. PMID:16471433

  11. Deformable image registration of CT and truncated cone-beam CT for adaptive radiation therapy

    NASA Astrophysics Data System (ADS)

    Zhen, Xin; Yan, Hao; Zhou, Linghong; Jia, Xun; Jiang, Steve B.

    2013-11-01

    Truncation of a cone-beam computed tomography (CBCT) image, mainly caused by the limited field of view (FOV) of CBCT imaging, poses challenges to the problem of deformable image registration (DIR) between computed tomography (CT) and CBCT images in adaptive radiation therapy (ART). The missing information outside the CBCT FOV usually causes incorrect deformations when a conventional DIR algorithm is utilized, which may introduce significant errors in subsequent operations such as dose calculation. In this paper, based on the observation that the missing information in the CBCT image domain does exist in the projection image domain, we propose to solve this problem by developing a hybrid deformation/reconstruction algorithm. As opposed to deforming the CT image to match the truncated CBCT image, the CT image is deformed such that its projections match all the corresponding projection images for the CBCT image. An iterative forward-backward projection algorithm is developed. Six head-and-neck cancer patient cases are used to evaluate our algorithm, five with simulated truncation and one with real truncation. It is found that our method can accurately register the CT image to the truncated CBCT image and is robust against image truncation when the portion of the truncated image is less than 40% of the total image. Part of this work was presented at the 54th AAPM Annual Meeting (Charlotte, NC, USA, 29 July-2 August 2012).

  12. Novel Algorithm for Classification of Medical Images

    NASA Astrophysics Data System (ADS)

    Bhushan, Bharat; Juneja, Monika

    2010-11-01

    Content-based image retrieval (CBIR) methods in medical image databases have been designed to support specific tasks, such as retrieval of medical images. These methods cannot be transferred to other medical applications since different imaging modalities require different types of processing. To enable content-based queries in diverse collections of medical images, the retrieval system must be familiar with the current Image class prior to the query processing. Further, almost all of them deal with the DICOM imaging format. In this paper a novel algorithm based on energy information obtained from wavelet transform for the classification of medical images according to their modalities is described. For this two types of wavelets have been used and have been shown that energy obtained in either case is quite distinct for each of the body part. This technique can be successfully applied to different image formats. The results are shown for JPEG imaging format.

  13. Wide coverage by volume CT: benefits for cardiac imaging

    NASA Astrophysics Data System (ADS)

    Sablayrolles, Jean-Louis; Cesmeli, Erdogan; Mintandjian, Laura; Adda, Olivier; Dessalles-Martin, Diane

    2005-04-01

    With the development of new technologies, computed tomography (CT) is becoming a strong candidate for non-invasive imaging based tool for cardiac disease assessment. One of the challenges of cardiac CT is that a typical scan involves a breath hold period consisting of several heartbeats, about 20 sec with scanners having a longitudinal coverage of 2 cm, and causing the image quality (IQ) to be negatively impacted since beat to beat variation is high likely to occur without any medication, e.g. beta blockers. Because of this and the preference for shorter breath hold durations, a CT scanner with a wide coverage without the compromise in the spatial and temporal resolution of great clinical value. In this study, we aimed at determining the optimum scan duration and the delay relative to beginning of breath hold, to achieve high IQ. We acquired EKG data from 91 consecutive patients (77 M, 14 F; Age: 57 +/- 14) undergoing cardiac CT exams with contrast, performed on LightSpeed 16 and LightSpeed Pro16. As an IQ metric, we adopted the standard deviation of "beat-to-beat variation" (stdBBV) within a virtual scan period. Two radiologists evaluated images by assigning a score of 1 (worst) to 4 best). We validated stdBBV with the radiologist scores, which resulted in a population distribution of 9.5, 9.5, 31, and 50% for the score groups 1, 2, 3, and 4, respectively. Based on the scores, we defined a threshold for stdBBV and identified an optimum combination of virtual scan period and a delay. With the assumption that the relationship between the stdBBV and diagnosable scan IQ holds, our analysis suggested that the success rate can be improved to 100% with scan durations equal or less than 5 sec with a delay of 1 - 2 sec. We confirmed the suggested conclusion with LightSpeed VCT (GE Healthcare Technologies, Waukesha, WI), which has a wide longitudinal coverage, fine isotropic spatial resolution, and high temporal resolution, e.g. 40 mm coverage per rotation of 0.35 sec

  14. Optimization of CT image reconstruction algorithms for the lung tissue research consortium (LTRC)

    NASA Astrophysics Data System (ADS)

    McCollough, Cynthia; Zhang, Jie; Bruesewitz, Michael; Bartholmai, Brian

    2006-03-01

    To create a repository of clinical data, CT images and tissue samples and to more clearly understand the pathogenetic features of pulmonary fibrosis and emphysema, the National Heart, Lung, and Blood Institute (NHLBI) launched a cooperative effort known as the Lung Tissue Resource Consortium (LTRC). The CT images for the LTRC effort must contain accurate CT numbers in order to characterize tissues, and must have high-spatial resolution to show fine anatomic structures. This study was performed to optimize the CT image reconstruction algorithms to achieve these criteria. Quantitative analyses of phantom and clinical images were conducted. The ACR CT accreditation phantom containing five regions of distinct CT attenuations (CT numbers of approximately -1000 HU, -80 HU, 0 HU, 130 HU and 900 HU), and a high-contrast spatial resolution test pattern, was scanned using CT systems from two manufacturers (General Electric (GE) Healthcare and Siemens Medical Solutions). Phantom images were reconstructed using all relevant reconstruction algorithms. Mean CT numbers and image noise (standard deviation) were measured and compared for the five materials. Clinical high-resolution chest CT images acquired on a GE CT system for a patient with diffuse lung disease were reconstructed using BONE and STANDARD algorithms and evaluated by a thoracic radiologist in terms of image quality and disease extent. The clinical BONE images were processed with a 3 x 3 x 3 median filter to simulate a thicker slice reconstructed in smoother algorithms, which have traditionally been proven to provide an accurate estimation of emphysema extent in the lungs. Using a threshold technique, the volume of emphysema (defined as the percentage of lung voxels having a CT number lower than -950 HU) was computed for the STANDARD, BONE, and BONE filtered. The CT numbers measured in the ACR CT Phantom images were accurate for all reconstruction kernels for both manufacturers. As expected, visual evaluation of the

  15. Quantitative image quality evaluation for cardiac CT reconstructions

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  16. Dual-energy CT imaging of thoracic malignancies

    PubMed Central

    Zhang, Long Jiang; Yang, Gui Fen; Wu, Sheng Yong; Lu, Guang Ming; Schoepf, U. Joseph

    2013-01-01

    Abstract Computed tomography (CT) plays a pivotal role in the detection, characterization, and staging of lung cancer and other thoracic malignancies. Since the introduction of clinically viable dual-energy CT techniques, substantial evidence has accumulated on the use of this modality for imaging chest malignancies. This article describes the principles of dual-energy CT along with suitable image acquisition, reconstruction, and postprocessing strategies for oncologic applications in the chest. The potential of dual-energy CT techniques for the detection, characterization, staging, and surveillance of chest malignancy, as well as the limitations of this modality are discussed. PMID:23470989

  17. Accelerated Compressed Sensing Based CT Image Reconstruction

    PubMed Central

    Hashemi, SayedMasoud; Beheshti, Soosan; Gill, Patrick R.; Paul, Narinder S.; Cobbold, Richard S. C.

    2015-01-01

    In X-ray computed tomography (CT) an important objective is to reduce the radiation dose without significantly degrading the image quality. Compressed sensing (CS) enables the radiation dose to be reduced by producing diagnostic images from a limited number of projections. However, conventional CS-based algorithms are computationally intensive and time-consuming. We propose a new algorithm that accelerates the CS-based reconstruction by using a fast pseudopolar Fourier based Radon transform and rebinning the diverging fan beams to parallel beams. The reconstruction process is analyzed using a maximum-a-posterior approach, which is transformed into a weighted CS problem. The weights involved in the proposed model are calculated based on the statistical characteristics of the reconstruction process, which is formulated in terms of the measurement noise and rebinning interpolation error. Therefore, the proposed method not only accelerates the reconstruction, but also removes the rebinning and interpolation errors. Simulation results are shown for phantoms and a patient. For example, a 512 × 512 Shepp-Logan phantom when reconstructed from 128 rebinned projections using a conventional CS method had 10% error, whereas with the proposed method the reconstruction error was less than 1%. Moreover, computation times of less than 30 sec were obtained using a standard desktop computer without numerical optimization. PMID:26167200

  18. SU-C-9A-06: The Impact of CT Image Used for Attenuation Correction in 4D-PET

    SciTech Connect

    Cui, Y; Bowsher, J; Yan, S; Cai, J; Das, S; Yin, F

    2014-06-01

    Purpose: To evaluate the appropriateness of using 3D non-gated CT image for attenuation correction (AC) in a 4D-PET (gated PET) imaging protocol used in radiotherapy treatment planning simulation. Methods: The 4D-PET imaging protocol in a Siemens PET/CT simulator (Biograph mCT, Siemens Medical Solutions, Hoffman Estates, IL) was evaluated. CIRS Dynamic Thorax Phantom (CIRS Inc., Norfolk, VA) with a moving glass sphere (8 mL) in the middle of its thorax portion was used in the experiments. The glass was filled with {sup 18}F-FDG and was in a longitudinal motion derived from a real patient breathing pattern. Varian RPM system (Varian Medical Systems, Palo Alto, CA) was used for respiratory gating. Both phase-gating and amplitude-gating methods were tested. The clinical imaging protocol was modified to use three different CT images for AC in 4D-PET reconstruction: first is to use a single-phase CT image to mimic actual clinical protocol (single-CT-PET); second is to use the average intensity projection CT (AveIP-CT) derived from 4D-CT scanning (AveIP-CT-PET); third is to use 4D-CT image to do the phase-matched AC (phase-matching- PET). Maximum SUV (SUVmax) and volume of the moving target (glass sphere) with threshold of 40% SUVmax were calculated for comparison between 4D-PET images derived with different AC methods. Results: The SUVmax varied 7.3%±6.9% over the breathing cycle in single-CT-PET, compared to 2.5%±2.8% in AveIP-CT-PET and 1.3%±1.2% in phasematching PET. The SUVmax in single-CT-PET differed by up to 15% from those in phase-matching-PET. The target volumes measured from single- CT-PET images also presented variations up to 10% among different phases of 4D PET in both phase-gating and amplitude-gating experiments. Conclusion: Attenuation correction using non-gated CT in 4D-PET imaging is not optimal process for quantitative analysis. Clinical 4D-PET imaging protocols should consider phase-matched 4D-CT image if available to achieve better accuracy.

  19. Ring artifacts removal from synchrotron CT image slices

    NASA Astrophysics Data System (ADS)

    Wei, Zhouping; Wiebe, Sheldon; Chapman, Dean

    2013-06-01

    Ring artifacts can occur in reconstructed images from x-ray Computerized Tomography (CT) as full or partial concentric rings superimposed on the scanned structures. Due to the data corruption by those ring artifacts in CT images, qualitative and quantitative analysis of these images are compromised. In this paper, we propose to correct the ring artifacts on the reconstructed synchrotron radiation (SR) CT image slices. The proposed correction procedure includes the following steps: (1). transform the reconstructed CT images into polar coordinates; (2) apply discrete two-dimensional (2D) wavelet transform to the polar image to decompose it into four image components: low pass band image component, as well as the components from horizontal, vertical and diagonal details bands; (3). apply 2D Fourier transform to the vertical details band image component only, since the ring artifacts become vertical lines in the polar coordinates; (4). apply Gaussian filtering in Fourier domain along the abscissa direction to suppress the vertical lines, since the information of the vertical lines in Fourier domain is completely condensed to that direction; (5). perform inverse Fourier transform to get the corrected vertical details band image component; (6). perform inverse wavelet transform to get the corrected polar image; (7). transform the corrected polar image back to Cartesian coordinates to get the CT image slice with reduced ring artifacts. This approach has been successfully used on CT data acquired from the Biomedical Imaging and Therapy (BMIT) beamline in Canadian Light Source (CLS), and the results show that the ring artifacts in original SR CT images have been effectively suppressed with all the structure information in the image preserved.

  20. Calibrated parametric medical ultrasound imaging.

    PubMed

    Valckx, F M; Thijsse, J M; van Geemen, A J; Rotteveel, J J; Mullaart, R

    2000-01-01

    The goal of this study was to develop a calibrated on-line technique to extract as much diagnostically-relevant information as possible from conventional video-format echograms. The final aim is to improve the diagnostic potentials of medical ultrasound. Video-output images were acquired by a frame grabber board incorporated in a multiprocessor workstation. Calibration images were obtained from a stable tissue-mimicking phantom with known acoustic characteristics. Using these images as reference, depth dependence of the gray level could fairly be corrected for the transducer performance characteristics, for the observer-dependent equipment settings and for attenuation in the examined tissues. Second-order statistical parameters still displayed some nonconsistent depth dependencies. The results obtained with two echoscanners for the same phantom were different; hence, an a posteriori normalization of clinical data with the phantom data is indicated. Prior to processing of clinical echograms,. the anatomical reflections and echoless voids were removed automatically. The final step in the preprocessing concerned the compensation of the overall attenuation in the tissue. A 'sliding window' processing was then applied to a region of interest (ROI) in the 'back-scan converted' images. A number of first and second order statistical texture parameters and acoustical parameters were estimated in each window and assigned to the central pixel. This procedure results in a set of new 'parametric' images of the ROI, which can be inserted in the original echogram (gray value, color) or presented as a color overlay. A clinical example is presented for illustrating the potentials of the developed technique. Depending on the choice of the parameters, four full resolution calibrated parametric images can be calculated and simultaneously displayed within 5 to 20 seconds. In conclusion, an on-line technique has been developed to estimate acoustic and texture parameters with a reduced

  1. Photon counting spectral CT versus conventional CT: comparative evaluation for breast imaging application

    NASA Astrophysics Data System (ADS)

    Shikhaliev, Polad M.; Fritz, Shannon G.

    2011-04-01

    Spectral CT systems with photon counting detectors have more advantages compared to conventional CT systems. However, clinical applications have been hampered for a long time due to the high demands of clinical systems and limitations of spectroscopic x-ray detectors. Photon counting detector technology has gained considerable improvements in the past decade, and spectral CT has become a hot topic. Several experimental spectral CT systems are under investigation. The purpose of this work was to perform the first direct, side-by-side comparison of existing spectral CT technology with a mature clinical CT system based on a conventional energy integrating detector. We have built an experimental spectral CT system whose main parameters are similar to the parameters of a clinical CT system. The system uses a spectroscopic cadmium zinc telluride (CZT) detector. The detector includes two rows of CZT pixels with 256 pixels in each row. The pixel size is 1 × 1 mm2, and the maximum count rate is 2 Mcounts/pixel/s. The spectral CT system has a magnification factor of 1.62 and the source to detector and source to image distances of 85 and 53 cm, respectively. The above parameters are similar to those of the clinical CT system, Siemens Sensation 16, used for comparison. The two systems were compared by imaging spatial resolution and contrast resolution phantoms made from acrylic cylinders with 14 cm diameters. The resolution phantom included Al wires with 0.3, 0.6, and 1 mm diameters, and 0.25 g cc-1 CaCO3 contrast. The contrast phantom included contrast elements with 1.7, 5, and 15 mg cc-1 iodine, and 1.1, 3.3, and 10 mg cc-1 gadolinium. The phantoms were imaged with the two systems using 120 kVp tube voltage and 470 mR total skin exposure. The spectral CT showed CT numbers, image noise, and spatial and contrast resolutions to be similar within 10% compared to the Siemens 16 system, and provided an average of 10% higher CNR. However, the spectral CT system had a major

  2. Medical Image Retrieval: A Multimodal Approach

    PubMed Central

    Cao, Yu; Steffey, Shawn; He, Jianbiao; Xiao, Degui; Tao, Cui; Chen, Ping; Müller, Henning

    2014-01-01

    Medical imaging is becoming a vital component of war on cancer. Tremendous amounts of medical image data are captured and recorded in a digital format during cancer care and cancer research. Facing such an unprecedented volume of image data with heterogeneous image modalities, it is necessary to develop effective and efficient content-based medical image retrieval systems for cancer clinical practice and research. While substantial progress has been made in different areas of content-based image retrieval (CBIR) research, direct applications of existing CBIR techniques to the medical images produced unsatisfactory results, because of the unique characteristics of medical images. In this paper, we develop a new multimodal medical image retrieval approach based on the recent advances in the statistical graphic model and deep learning. Specifically, we first investigate a new extended probabilistic Latent Semantic Analysis model to integrate the visual and textual information from medical images to bridge the semantic gap. We then develop a new deep Boltzmann machine-based multimodal learning model to learn the joint density model from multimodal information in order to derive the missing modality. Experimental results with large volume of real-world medical images have shown that our new approach is a promising solution for the next-generation medical imaging indexing and retrieval system. PMID:26309389

  3. Medical Image Retrieval: A Multimodal Approach.

    PubMed

    Cao, Yu; Steffey, Shawn; He, Jianbiao; Xiao, Degui; Tao, Cui; Chen, Ping; Müller, Henning

    2014-01-01

    Medical imaging is becoming a vital component of war on cancer. Tremendous amounts of medical image data are captured and recorded in a digital format during cancer care and cancer research. Facing such an unprecedented volume of image data with heterogeneous image modalities, it is necessary to develop effective and efficient content-based medical image retrieval systems for cancer clinical practice and research. While substantial progress has been made in different areas of content-based image retrieval (CBIR) research, direct applications of existing CBIR techniques to the medical images produced unsatisfactory results, because of the unique characteristics of medical images. In this paper, we develop a new multimodal medical image retrieval approach based on the recent advances in the statistical graphic model and deep learning. Specifically, we first investigate a new extended probabilistic Latent Semantic Analysis model to integrate the visual and textual information from medical images to bridge the semantic gap. We then develop a new deep Boltzmann machine-based multimodal learning model to learn the joint density model from multimodal information in order to derive the missing modality. Experimental results with large volume of real-world medical images have shown that our new approach is a promising solution for the next-generation medical imaging indexing and retrieval system. PMID:26309389

  4. Medical Image Compression Using a New Subband Coding Method

    NASA Technical Reports Server (NTRS)

    Kossentini, Faouzi; Smith, Mark J. T.; Scales, Allen; Tucker, Doug

    1995-01-01

    A recently introduced iterative complexity- and entropy-constrained subband quantization design algorithm is generalized and applied to medical image compression. In particular, the corresponding subband coder is used to encode Computed Tomography (CT) axial slice head images, where statistical dependencies between neighboring image subbands are exploited. Inter-slice conditioning is also employed for further improvements in compression performance. The subband coder features many advantages such as relatively low complexity and operation over a very wide range of bit rates. Experimental results demonstrate that the performance of the new subband coder is relatively good, both objectively and subjectively.

  5. Computer-aided diagnosis workstation and network system for chest diagnosis based on multislice CT images

    NASA Astrophysics Data System (ADS)

    Satoh, Hitoshi; Niki, Noboru; Eguchi, Kenji; Moriyama, Noriyuki; Ohmatsu, Hironobu; Masuda, Hideo; Machida, Suguru

    2008-03-01

    Mass screening based on multi-helical CT images requires a considerable number of images to be read. It is this time-consuming step that makes the use of helical CT for mass screening impractical at present. To overcome this problem, we have provided diagnostic assistance methods to medical screening specialists by developing a lung cancer screening algorithm that automatically detects suspected lung cancers in helical CT images, a coronary artery calcification screening algorithm that automatically detects suspected coronary artery calcification and a vertebra body analysis algorithm for quantitative evaluation of osteoporosis likelihood by using helical CT scanner for the lung cancer mass screening. The function to observe suspicious shadow in detail are provided in computer-aided diagnosis workstation with these screening algorithms. We also have developed the telemedicine network by using Web medical image conference system with the security improvement of images transmission, Biometric fingerprint authentication system and Biometric face authentication system. Biometric face authentication used on site of telemedicine makes "Encryption of file" and Success in login" effective. As a result, patients' private information is protected. Based on these diagnostic assistance methods, we have developed a new computer-aided workstation and a new telemedicine network that can display suspected lesions three-dimensionally in a short time. The results of this study indicate that our radiological information system without film by using computer-aided diagnosis workstation and our telemedicine network system can increase diagnostic speed, diagnostic accuracy and security improvement of medical information.

  6. A generalized method of converting CT image to PET linear attenuation coefficient distribution in PET/CT imaging

    NASA Astrophysics Data System (ADS)

    Wang, Lu; Wu, Li-Wei; Wei, Le; Gao, Juan; Sun, Cui-Li; Chai, Pei; Li, Dao-Wu

    2014-02-01

    The accuracy of attenuation correction in positron emission tomography scanners depends mainly on deriving the reliable 511-keV linear attenuation coefficient distribution in the scanned objects. In the PET/CT system, the linear attenuation distribution is usually obtained from the intensities of the CT image. However, the intensities of the CT image relate to the attenuation of photons in an energy range of 40 keV-140 keV. Before implementing PET attenuation correction, the intensities of CT images must be transformed into the PET 511-keV linear attenuation coefficients. However, the CT scan parameters can affect the effective energy of CT X-ray photons and thus affect the intensities of the CT image. Therefore, for PET/CT attenuation correction, it is crucial to determine the conversion curve with a given set of CT scan parameters and convert the CT image into a PET linear attenuation coefficient distribution. A generalized method is proposed for converting a CT image into a PET linear attenuation coefficient distribution. Instead of some parameter-dependent phantom calibration experiments, the conversion curve is calculated directly by employing the consistency conditions to yield the most consistent attenuation map with the measured PET data. The method is evaluated with phantom experiments and small animal experiments. In phantom studies, the estimated conversion curve fits the true attenuation coefficients accurately, and accurate PET attenuation maps are obtained by the estimated conversion curves and provide nearly the same correction results as the true attenuation map. In small animal studies, a more complicated attenuation distribution of the mouse is obtained successfully to remove the attenuation artifact and improve the PET image contrast efficiently.

  7. Image reconstruction for PET/CT scanners: past achievements and future challenges

    PubMed Central

    Tong, Shan; Alessio, Adam M; Kinahan, Paul E

    2011-01-01

    PET is a medical imaging modality with proven clinical value for disease diagnosis and treatment monitoring. The integration of PET and CT on modern scanners provides a synergy of the two imaging modalities. Through different mathematical algorithms, PET data can be reconstructed into the spatial distribution of the injected radiotracer. With dynamic imaging, kinetic parameters of specific biological processes can also be determined. Numerous efforts have been devoted to the development of PET image reconstruction methods over the last four decades, encompassing analytic and iterative reconstruction methods. This article provides an overview of the commonly used methods. Current challenges in PET image reconstruction include more accurate quantitation, TOF imaging, system modeling, motion correction and dynamic reconstruction. Advances in these aspects could enhance the use of PET/CT imaging in patient care and in clinical research studies of pathophysiology and therapeutic interventions. PMID:21339831

  8. Medical Imaging Physics, 4th Edition

    NASA Astrophysics Data System (ADS)

    Hendee, William R.; Ritenour, E. Russell

    2002-05-01

    This comprehensive publication covers all aspects of image formation in modern medical imaging modalities, from radiography, fluoroscopy, and computed tomography, to magnetic resonance imaging and ultrasound. It addresses the techniques and instrumentation used in the rapidly changing field of medical imaging. Now in its fourth edition, this text provides the reader with the tools necessary to be comfortable with the physical principles, equipment, and procedures used in diagnostic imaging, as well as appreciate the capabilities and limitations of the technologies.

  9. NASA Technology Finds Uses in Medical Imaging

    NASA Video Gallery

    NASA software has been incorporated into a new medical imaging device that could one day aid in the interpretation of mammograms, ultrasounds, and other medical imagery. The new MED-SEG system, dev...

  10. Optimization of SPECT-CT Hybrid Imaging Using Iterative Image Reconstruction for Low-Dose CT: A Phantom Study

    PubMed Central

    Grosser, Oliver S.; Kupitz, Dennis; Ruf, Juri; Czuczwara, Damian; Steffen, Ingo G.; Furth, Christian; Thormann, Markus; Loewenthal, David; Ricke, Jens; Amthauer, Holger

    2015-01-01

    Background Hybrid imaging combines nuclear medicine imaging such as single photon emission computed tomography (SPECT) or positron emission tomography (PET) with computed tomography (CT). Through this hybrid design, scanned patients accumulate radiation exposure from both applications. Imaging modalities have been the subject of long-term optimization efforts, focusing on diagnostic applications. It was the aim of this study to investigate the influence of an iterative CT image reconstruction algorithm (ASIR) on the image quality of the low-dose CT images. Methodology/Principal Findings Examinations were performed with a SPECT-CT scanner with standardized CT and SPECT-phantom geometries and CT protocols with systematically reduced X-ray tube currents. Analyses included image quality with respect to photon flux. Results were compared to the standard FBP reconstructed images. The general impact of the CT-based attenuation maps used during SPECT reconstruction was examined for two SPECT phantoms. Using ASIR for image reconstructions, image noise was reduced compared to FBP reconstructions for the same X-ray tube current. The Hounsfield unit (HU) values reconstructed by ASIR were correlated to the FBP HU values(R2 ≥ 0.88) and the contrast-to-noise ratio (CNR) was improved by ASIR. However, for a phantom with increased attenuation, the HU values shifted for low X-ray tube currents I ≤ 60 mA (p ≤ 0.04). In addition, the shift of the HU values was observed within the attenuation corrected SPECT images for very low X-ray tube currents (I ≤ 20 mA, p ≤ 0.001). Conclusion/Significance In general, the decrease in X-ray tube current up to 30 mA in combination with ASIR led to a reduction of CT-related radiation exposure without a significant decrease in image quality. PMID:26390216

  11. Patient-specific CT dose determination from CT images using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Liang, Qing

    Radiation dose from computed tomography (CT) has become a public concern with the increasing application of CT as a diagnostic modality, which has generated a demand for patient-specific CT dose determinations. This thesis work aims to provide a clinically applicable Monte-Carlo-based CT dose calculation tool based on patient CT images. The source spectrum was simulated based on half-value layer measurements. Analytical calculations along with the measured flux distribution were used to estimate the bowtie-filter geometry. Relative source output at different points in a cylindrical phantom was measured and compared with Monte Carlo simulations to verify the determined spectrum and bowtie-filter geometry. Sensitivity tests were designed with four spectra with the same kVp and different half-value layers, and showed that the relative output at different locations in a phantom is sensitive to different beam qualities. An mAs-to-dose conversion factor was determined with in-air measurements using an Exradin A1SL ionization chamber. Longitudinal dose profiles were measured with thermoluminescent dosimeters (TLDs) and compared with the Monte-Carlo-simulated dose profiles to verify the mAs-to-dose conversion factor. Using only the CT images to perform Monte Carlo simulations would cause dose underestimation due to the lack of a scatter region. This scenario was demonstrated with a cylindrical phantom study. Four different image extrapolation methods from the existing CT images and the Scout images were proposed. The results show that performing image extrapolation beyond the scan region improves the dose calculation accuracy under both step-shoot scan mode and helical scan mode. Two clinical studies were designed and comparisons were performed between the current CT dose metrics and the Monte-Carlo-based organ dose determination techniques proposed in this work. The results showed that the current CT dosimetry failed to show dose differences between patients with the same

  12. 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.

  13. CT Dose Optimization in Pediatric Radiology: A Multiyear Effort to Preserve the Benefits of Imaging While Reducing the Risks.

    PubMed

    Greenwood, Taylor J; Lopez-Costa, Rodrigo I; Rhoades, Patrick D; Ramírez-Giraldo, Juan C; Starr, Matthew; Street, Mandie; Duncan, James; McKinstry, Robert C

    2015-01-01

    The marked increase in radiation exposure from medical imaging, especially in children, has caused considerable alarm and spurred efforts to preserve the benefits but reduce the risks of imaging. Applying the principles of the Image Gently campaign, data-driven process and quality improvement techniques such as process mapping and flowcharting, cause-and-effect diagrams, Pareto analysis, statistical process control (control charts), failure mode and effects analysis, "lean" or Six Sigma methodology, and closed feedback loops led to a multiyear program that has reduced overall computed tomographic (CT) examination volume by more than fourfold and concurrently decreased radiation exposure per CT study without compromising diagnostic utility. This systematic approach involving education, streamlining access to magnetic resonance imaging and ultrasonography, auditing with comparison with benchmarks, applying modern CT technology, and revising CT protocols has led to a more than twofold reduction in CT radiation exposure between 2005 and 2012 for patients at the authors' institution while maintaining diagnostic utility. PMID:26267677

  14. Deformable planning CT to cone-beam CT image registration in head-and-neck cancer

    SciTech Connect

    Hou Jidong; Guerrero, Mariana; Chen, Wenjuan; D'Souza, Warren D.

    2011-04-15

    Purpose: The purpose of this work was to implement and validate a deformable CT to cone-beam computed tomography (CBCT) image registration method in head-and-neck cancer to eventually facilitate automatic target delineation on CBCT. Methods: Twelve head-and-neck cancer patients underwent a planning CT and weekly CBCT during the 5-7 week treatment period. The 12 planning CT images (moving images) of these patients were registered to their weekly CBCT images (fixed images) via the symmetric force Demons algorithm and using a multiresolution scheme. Histogram matching was used to compensate for the intensity difference between the two types of images. Using nine known anatomic points as registration targets, the accuracy of the registration was evaluated using the target registration error (TRE). In addition, region-of-interest (ROI) contours drawn on the planning CT were morphed to the CBCT images and the volume overlap index (VOI) between registered contours and manually delineated contours was evaluated. Results: The mean TRE value of the nine target points was less than 3.0 mm, the slice thickness of the planning CT. Of the 369 target points evaluated for registration accuracy, the average TRE value was 2.6{+-}0.6 mm. The mean TRE for bony tissue targets was 2.4{+-}0.2 mm, while the mean TRE for soft tissue targets was 2.8{+-}0.2 mm. The average VOI between the registered and manually delineated ROI contours was 76.2{+-}4.6%, which is consistent with that reported in previous studies. Conclusions: The authors have implemented and validated a deformable image registration method to register planning CT images to weekly CBCT images in head-and-neck cancer cases. The accuracy of the TRE values suggests that they can be used as a promising tool for automatic target delineation on CBCT.

  15. Monte Carlo PENRADIO software for dose calculation in medical imaging

    NASA Astrophysics Data System (ADS)

    Adrien, Camille; Lòpez Noriega, Mercedes; Bonniaud, Guillaume; Bordy, Jean-Marc; Le Loirec, Cindy; Poumarede, Bénédicte

    2014-06-01

    The increase on the collective radiation dose due to the large number of medical imaging exams has led the medical physics community to deeply consider the amount of dose delivered and its associated risks in these exams. For this purpose we have developed a Monte Carlo tool, PENRADIO, based on a modified version of PENELOPE code 2006 release, to obtain an accurate individualized radiation dose in conventional and interventional radiography and in computed tomography (CT). This tool has been validated showing excellent agreement between the measured and simulated organ doses in the case of a hip conventional radiography and a coronography. We expect the same accuracy in further results for other localizations and CT examinations.

  16. The Handbook of Medical Image Perception and Techniques

    NASA Astrophysics Data System (ADS)

    Samei, Ehsan; Krupinski, Elizabeth

    2014-07-01

    1. Medical image perception Ehsan Samei and Elizabeth Krupinski; Part I. Historical Reflections and Theoretical Foundations: 2. A short history of image perception in medical radiology Harold Kundel and Calvin Nodine; 3. Spatial vision research without noise Arthur Burgess; 4. Signal detection theory, a brief history Arthur Burgess; 5. Signal detection in radiology Arthur Burgess; 6. Lessons from dinners with the giants of modern image science Robert Wagner; Part II. Science of Image Perception: 7. Perceptual factors in reading medical images Elizabeth Krupinski; 8. Cognitive factors in reading medical images David Manning; 9. Satisfaction of search in traditional radiographic imaging Kevin Berbaum, Edmund Franken, Robert Caldwell and Kevin Schartz; 10. The role of expertise in radiologic image interpretation Calvin Nodine and Claudia Mello-Thoms; 11. A primer of image quality and its perceptual relevance Robert Saunders and Ehsan Samei; 12. Beyond the limitations of human vision Maria Petrou; Part III. Perception Metrology: 13. Logistical issues in designing perception experiments Ehsan Samei and Xiang Li; 14. ROC analysis: basic concepts and practical applications Georgia Tourassi; 15. Multi-reader ROC Steve Hillis; 16. Recent developments in FROC methodology Dev Chakraborty; 17. Observer models as a surrogate to perception experiments Craig Abbey and Miguel Eckstein; 18. Implementation of observer models Matthew Kupinski; Part IV. Decision Support and Computer Aided Detection: 19. CAD: an image perception perspective Maryellen Giger and Weijie Chen; 20. Common designs of CAD studies Yulei Jiang; 21. Perceptual effect of CAD in reading chest images Matthew Freedman and Teresa Osicka; 22. Perceptual issues in mammography and CAD Michael Ulissey; 23. How perceptual factors affect the use and accuracy of CAD for interpretation of CT images Ronald Summers; 24. CAD: risks and benefits for radiologists' decisions Eugenio Alberdi, Andrey Povyakalo, Lorenzo Strigini and

  17. The Handbook of Medical Image Perception and Techniques

    NASA Astrophysics Data System (ADS)

    Samei, Ehsan; Krupinski, Elizabeth

    2009-12-01

    1. Medical image perception Ehsan Samei and Elizabeth Krupinski; Part I. Historical Reflections and Theoretical Foundations: 2. A short history of image perception in medical radiology Harold Kundel and Calvin Nodine; 3. Spatial vision research without noise Arthur Burgess; 4. Signal detection theory, a brief history Arthur Burgess; 5. Signal detection in radiology Arthur Burgess; 6. Lessons from dinners with the giants of modern image science Robert Wagner; Part II. Science of Image Perception: 7. Perceptual factors in reading medical images Elizabeth Krupinski; 8. Cognitive factors in reading medical images David Manning; 9. Satisfaction of search in traditional radiographic imaging Kevin Berbaum, Edmund Franken, Robert Caldwell and Kevin Schartz; 10. The role of expertise in radiologic image interpretation Calvin Nodine and Claudia Mello-Thoms; 11. A primer of image quality and its perceptual relevance Robert Saunders and Ehsan Samei; 12. Beyond the limitations of human vision Maria Petrou; Part III. Perception Metrology: 13. Logistical issues in designing perception experiments Ehsan Samei and Xiang Li; 14. ROC analysis: basic concepts and practical applications Georgia Tourassi; 15. Multi-reader ROC Steve Hillis; 16. Recent developments in FROC methodology Dev Chakraborty; 17. Observer models as a surrogate to perception experiments Craig Abbey and Miguel Eckstein; 18. Implementation of observer models Matthew Kupinski; Part IV. Decision Support and Computer Aided Detection: 19. CAD: an image perception perspective Maryellen Giger and Weijie Chen; 20. Common designs of CAD studies Yulei Jiang; 21. Perceptual effect of CAD in reading chest images Matthew Freedman and Teresa Osicka; 22. Perceptual issues in mammography and CAD Michael Ulissey; 23. How perceptual factors affect the use and accuracy of CAD for interpretation of CT images Ronald Summers; 24. CAD: risks and benefits for radiologists' decisions Eugenio Alberdi, Andrey Povyakalo, Lorenzo Strigini and

  18. Holography and the virtual patient: the holographic medical image

    NASA Astrophysics Data System (ADS)

    Ko, Kathryn; Erickson, Ronald R.; Webster, John M.

    1996-12-01

    Practical holographic systems utilizing the pulsed laser are finding potential applications in medicine. Exploiting both the hologram's true 3D image and holographic interferometry these techniques enhance the physician's vision beyond the 2D radiological imaging of even the best CT and MRI. The authors describe the use of pulsed laser holography as applied to the morphological specialties: anatomy, pathology, and surgery. The authors report on the Holographic Brain Anatomy Atlas for medical education; pathologic documentation with holography, and the use of holographic interferometry in surgical planning. The techniques are outlined and a discussion on the interpretation of holographic interferometry with living subjects is provided.

  19. Joint detection and segmentation of vertebral bodies in CT images by sparse representation error minimization

    NASA Astrophysics Data System (ADS)

    Korez, Robert; Likar, Boštjan; Pernuš, Franjo; Vrtovec, Tomaž

    2016-03-01

    Automated detection and segmentation of vertebral bodies from spinal computed tomography (CT) images is usually a prerequisite step for numerous spine-related medical applications, such as diagnosis, surgical planning and follow-up assessment of spinal pathologies. However, automated detection and segmentation are challenging tasks due to a relatively high degree of anatomical complexity, presence of unclear boundaries and articulation of vertebrae with each other. In this paper, we describe a sparse representation error minimization (SEM) framework for joint detection and segmentation of vertebral bodies in CT images. By minimizing the sparse representation error of sampled intensity values, we are able to recover the oriented bounding box (OBB) and segmentation binary mask for each vertebral body in the CT image. The performance of the proposed SEM framework was evaluated on five CT images of the thoracolumbar spine. The resulting Euclidean distance of 1:75+/-1:02 mm, computed between the center points of recovered and corresponding reference OBBs, and Dice coefficient of 92:3+/-2:7%, computed between the resulting and corresponding reference segmentation binary masks, indicate that the proposed framework can successfully detect and segment vertebral bodies in CT images of the thoracolumbar spine.

  20. Hybrid segmentation framework for 3D medical image analysis

    NASA Astrophysics Data System (ADS)

    Chen, Ting; Metaxas, Dimitri N.

    2003-05-01

    Medical image segmentation is the process that defines the region of interest in the image volume. Classical segmentation methods such as region-based methods and boundary-based methods cannot make full use of the information provided by the image. In this paper we proposed a general hybrid framework for 3D medical image segmentation purposes. In our approach we combine the Gibbs Prior model, and the deformable model. First, Gibbs Prior models are applied onto each slice in a 3D medical image volume and the segmentation results are combined to a 3D binary masks of the object. Then we create a deformable mesh based on this 3D binary mask. The deformable model will be lead to the edge features in the volume with the help of image derived external forces. The deformable model segmentation result can be used to update the parameters for Gibbs Prior models. These methods will then work recursively to reach a global segmentation solution. The hybrid segmentation framework has been applied to images with the objective of lung, heart, colon, jaw, tumor, and brain. The experimental data includes MRI (T1, T2, PD), CT, X-ray, Ultra-Sound images. High quality results are achieved with relatively efficient time cost. We also did validation work using expert manual segmentation as the ground truth. The result shows that the hybrid segmentation may have further clinical use.

  1. PET/CT Imaging in Mouse Models of Myocardial Ischemia

    PubMed Central

    Gargiulo, Sara; Greco, Adelaide; Gramanzini, Matteo; Petretta, Maria Piera; Ferro, Adele; Larobina, Michele; Panico, Mariarosaria; Brunetti, Arturo; Cuocolo, Alberto

    2012-01-01

    Different species have been used to reproduce myocardial infarction models but in the last years mice became the animals of choice for the analysis of several diseases, due to their short life cycle and the possibility of genetic manipulation. Many techniques are currently used for cardiovascular imaging in mice, including X-ray computed tomography (CT), high-resolution ultrasound, magnetic resonance imaging, and nuclear medicine procedures. Cardiac positron emission tomography (PET) allows to examine noninvasively, on a molecular level and with high sensitivity, regional changes in myocardial perfusion, metabolism, apoptosis, inflammation, and gene expression or to measure changes in anatomical and functional parameters in heart diseases. Currently hybrid PET/CT scanners for small laboratory animals are available, where CT adds high-resolution anatomical information. This paper reviews mouse models of myocardial infarction and discusses the applications of dedicated PET/CT systems technology, including animal preparation, anesthesia, radiotracers, and images postprocessing. PMID:22505813

  2. PET/CT imaging in mouse models of myocardial ischemia.

    PubMed

    Gargiulo, Sara; Greco, Adelaide; Gramanzini, Matteo; Petretta, Maria Piera; Ferro, Adele; Larobina, Michele; Panico, Mariarosaria; Brunetti, Arturo; Cuocolo, Alberto

    2012-01-01

    Different species have been used to reproduce myocardial infarction models but in the last years mice became the animals of choice for the analysis of several diseases, due to their short life cycle and the possibility of genetic manipulation. Many techniques are currently used for cardiovascular imaging in mice, including X-ray computed tomography (CT), high-resolution ultrasound, magnetic resonance imaging, and nuclear medicine procedures. Cardiac positron emission tomography (PET) allows to examine noninvasively, on a molecular level and with high sensitivity, regional changes in myocardial perfusion, metabolism, apoptosis, inflammation, and gene expression or to measure changes in anatomical and functional parameters in heart diseases. Currently hybrid PET/CT scanners for small laboratory animals are available, where CT adds high-resolution anatomical information. This paper reviews mouse models of myocardial infarction and discusses the applications of dedicated PET/CT systems technology, including animal preparation, anesthesia, radiotracers, and images postprocessing. PMID:22505813

  3. Thoracic cancer imaging with PET/CT in radiation oncology

    NASA Astrophysics Data System (ADS)

    Chi, Pai-Chun Melinda

    Significance. Respiratory motion has been shown to cause artifacts in PET/CT imaging. This breathing artifact can have a significant impact on PET quantification and it can lead to large uncertainties when using PET for radiation therapy planning. We have demonstrated a promising solution to resolve the breathing artifact by acquiring respiration-averaged CT (ACT) for PET/CT. The purpose of this work was to optimize the ACT acquisition for clinical implementation and to evaluate the impact of ACT on PET/CT quantification. The hypothesis was that ACT is an effective method in removing the breathing artifact when compared to our current clinical protocol. Methods. Phase and cine approaches for acquiring ACT were investigated and the results of these two approaches were compared to the ACT generated from clinical 4DCT data sets (abbreviated as ACT10phs ). In the phase approach, ACT was generated based on combinations of selected respiratory phases; in the cine approach, ACT was generated based on cine images acquired over a fixed cine duration. The phase combination and cine duration that best approximated the ACT10phs were determined to be the optimized scanning parameters. 216 thoracic PET/CT patients were scanned with both current clinical and the ACT protocols. The effects of ACT on PET/CT quantification were assessed by comparing clinical PET/CT and ACT PET/CT using 3 metrics: PET/CT image alignment, maximum standardized uptake value (SUVmax), and threshold segmented gross tumor volume (GTV). Results. ACT10phs can be best approximated to within 2% of SUV variation by phase averaging based on 4 representative phases, and to within 3% by cine image averaging based on >3s of cine duration. We implemented the cine approach on the PET/CT scanners and acquired 216 patient data sets. 68% of patients had breathing artifacts in their clinical PET/CT and the artifacts were removed/reduced in all corresponding ACT PET/CT. PET/CT quantification for lesions <50 cm3 and

  4. Medical imaging V: Image capture, formatting, and display

    SciTech Connect

    Kim, Y.

    1991-01-01

    This book is covered under the following topics: Digital image display I-V; Quality assurance I-V; Clinical image presentation I-V; Imaging systems; Image compression; Workstations; and Medical diagnostic imaging support system for military medicine and other federal agencies.

  5. TLD assessment of mouse dosimetry during microCT imaging

    SciTech Connect

    Figueroa, Said Daibes; Winkelmann, Christopher T.; Miller, William H.; Volkert, Wynn A.; Hoffman, Timothy J.

    2008-09-15

    Advances in laboratory animal imaging have provided new resources for noninvasive biomedical research. Among these technologies is microcomputed tomography (microCT) which is widely used to obtain high resolution anatomic images of small animals. Because microCT utilizes ionizing radiation for image formation, radiation exposure during imaging is a concern. The objective of this study was to quantify the radiation dose delivered during a standard microCT scan. Radiation dose was measured using thermoluminescent dosimeters (TLDs), which were irradiated employing an 80 kVp x-ray source, with 0.5 mm Al filtration and a total of 54 mA s for a full 360 deg rotation of the unit. The TLD data were validated using a 3.2 cm{sup 3} CT ion chamber probe. TLD results showed a single microCT scan air kerma of 78.0{+-}5.0 mGy when using a poly(methylmethacrylate) (PMMA) anesthesia support module and an air kerma of 92.0{+-}6.0 mGy without the use of the anesthesia module. The validation CT ion chamber study provided a measured radiation air kerma of 81.0{+-}4.0 mGy and 97.0{+-}5.0 mGy with and without the PMMA anesthesia module, respectively. Internal TLD analysis demonstrated an average mouse organ radiation absorbed dose of 76.0{+-}5.0 mGy. The author's results have defined x-ray exposure for a routine microCT study which must be taken into consideration when performing serial molecular imaging studies involving the microCT imaging modality.

  6. TLD assessment of mouse dosimetry during microCT imaging

    PubMed Central

    Figueroa, Said Daibes; Winkelmann, Christopher T.; Miller, William H.; Volkert, Wynn A.; Hoffman, Timothy J.

    2008-01-01

    Advances in laboratory animal imaging have provided new resources for noninvasive biomedical research. Among these technologies is microcomputed tomography (microCT) which is widely used to obtain high resolution anatomic images of small animals. Because microCT utilizes ionizing radiation for image formation, radiation exposure during imaging is a concern. The objective of this study was to quantify the radiation dose delivered during a standard microCT scan. Radiation dose was measured using thermoluminescent dosimeters (TLDs), which were irradiated employing an 80 kVp x-ray source, with 0.5 mm Al filtration and a total of 54 mA s for a full 360 deg rotation of the unit. The TLD data were validated using a 3.2 cm3 CT ion chamber probe. TLD results showed a single microCT scan air kerma of 78.0±5.0 mGy when using a poly(methylmethacrylate) (PMMA) anesthesia support module and an air kerma of 92.0±6.0 mGy without the use of the anesthesia module. The validation CT ion chamber study provided a measured radiation air kerma of 81.0±4.0 mGy and 97.0±5.0 mGy with and without the PMMA anesthesia module, respectively. Internal TLD analysis demonstrated an average mouse organ radiation absorbed dose of 76.0±5.0 mGy. The author’s results have defined x-ray exposure for a routine microCT study which must be taken into consideration when performing serial molecular imaging studies involving the microCT imaging modality. PMID:18841837

  7. Non-Rigid Registration of Liver CT Images for CT-Guided Ablation of Liver Tumors.

    PubMed

    Luu, Ha Manh; Klink, Camiel; Niessen, Wiro; Moelker, Adriaan; Walsum, Theo van

    2016-01-01

    CT-guided percutaneous ablation for liver cancer treatment is a relevant technique for patients not eligible for surgery and with tumors that are inconspicuous on US imaging. The lack of real-time imaging and the use of a limited amount of CT contrast agent make targeting the tumor with the needle challenging. In this study, we evaluate a registration framework that allows the integration of diagnostic pre-operative contrast enhanced CT images and intra-operative non-contrast enhanced CT images to improve image guidance in the intervention. The liver and tumor are segmented in the pre-operative contrast enhanced CT images. Next, the contrast enhanced image is registered to the intra-operative CT images in a two-stage approach. First, the contrast-enhanced diagnostic image is non-rigidly registered to a non-contrast enhanced image that is conventionally acquired at the start of the intervention. In case the initial registration is not sufficiently accurate, a refinement step is applied using non-rigid registration method with a local rigidity term. In the second stage, the intra-operative CT-images that are used to check the needle position, which often consist of only a few slices, are registered rigidly to the intra-operative image that was acquired at the start of the intervention. Subsequently, the diagnostic image is registered to the current intra-operative image, using both transformations, this allows the visualization of the tumor region extracted from pre-operative data in the intra-operative CT images containing needle. The method is evaluated on imaging data of 19 patients at the Erasmus MC. Quantitative evaluation is performed using the Dice metric, mean surface distance of the liver border and corresponding landmarks in the diagnostic and the intra-operative images. The registration of the diagnostic CT image to the initial intra-operative CT image did not require a refinement step in 13 cases. For those cases, the resulting registration had a Dice

  8. Current and Novel Imaging Techniques in Coronary CT.

    PubMed

    Machida, Haruhiko; Tanaka, Isao; Fukui, Rika; Shen, Yun; Ishikawa, Takuya; Tate, Etsuko; Ueno, Eiko

    2015-01-01

    Multidetector coronary computed tomography (CT), which is widely performed to assess coronary artery disease noninvasively and accurately, provides excellent image quality. Use of electrocardiography (ECG)-controlled tube current modulation and low tube voltage can reduce patient exposure to nephrotoxic contrast media and carcinogenic radiation when using standard coronary CT with a retrospective ECG-gated helical scan. Various imaging techniques are expected to overcome the limitations of standard coronary CT, which also include insufficient spatial and temporal resolution, beam-hardening artifacts, limited coronary plaque characterization, and an inability to allow functional assessment of coronary stenosis. Use of a step-and-shoot scan, iterative reconstruction, and a high-pitch dual-source helical scan can further reduce radiation dose. Dual-energy CT can improve contrast medium enhancement and reasonably reduce the contrast dose when combined with noise reduction with the use of iterative reconstruction. High-definition CT can improve spatial resolution and diagnostic evaluation of small or peripheral coronary vessels and coronary stents. Dual-source CT and a motion correction algorithm can improve temporal resolution and reduce coronary motion artifacts. Whole-heart coverage with 320-detector CT and an intelligent boundary registration algorithm can eliminate stair-step artifacts. By decreasing beam hardening and enabling material decomposition, dual-energy CT is expected to remove or reduce the depiction of coronary calcification to improve intraluminal evaluation of calcified vessels and to provide detailed analysis of coronary plaque components and accurate qualitative and quantitative assessment of myocardial perfusion. Fractional flow reserve derived from coronary CT is a state-of-the-art noninvasive technique for accurately identifying myocardial ischemia beyond coronary CT. Understanding these techniques is important to enhance the value of coronary CT

  9. From analogue to apps--developing an app to prepare children for medical imaging procedures.

    PubMed

    Williams, Gigi; Greene, Siobhan

    2015-01-01

    The Royal Children's Hospital (RCH) in Melbourne has launched a world-first app for children that will help reduce anxiety and the need for anesthesia during medical imaging procedures. The free, game-based app, "Okee in Medical Imaging", helps children aged from four to eight years to prepare for all medical imaging procedures--X-ray, CT, MRI, ultrasound, nuclear medicine, and fluoroscopy. The app is designed to reduce anticipatory fear of imaging procedures, while helping to ensure that children attend imaging appointments equipped with the skills required for efficient and effective scans to be performed. This paper describes how the app was developed. PMID:26828544

  10. Left-ventricular boundary detection from spatiotemporal volumetric CT images

    NASA Astrophysics Data System (ADS)

    Tu, Hsiao-Kun; Matheny, Art; Goldgof, Dmitry B.

    1993-07-01

    This paper presents a new technique for LV boundary detection from 3-D volumetric cardiac images. The proposed method consists of boundary detection and boundary refinement stages. In the boundary detection stage, a spatio-temporal (4-D) gradient operator is used to capture the temporal gradients of dynamic LV boundaries and to smooth time uncorrelated noise. Spatio-temporal edge detection is performed outward from an approximate center of the left ventricle. In the boundary refinement stage, spherical harmonic model is fitted to the detected boundaries. Based on this model, false boundaries are removed; LV boundaries are recovered. A left ventricle is a bright, smooth region, varying in size over the heart cycle. This a priori knowledge is incorporated in detection and refinement of LV boundaries to reduce the effect of noise. The intensity of the inner (close to the center) neighbors of the LV boundary is brighter than the outer. The size of the left ventricle is used in boundary refinement to select proper boundaries to be fitted by the spherical harmonic mode. We demonstrate the advantages of 4-D edge detection over 3-D and the use of spherical harmonics to refine LV boundaries. Our experimental data is supplied by Dr. Eric Hoffman at University of Pennsylvania medical school and consists of 16 volumetric (128 by 128 by 118) CT images taken through a heart cycle.

  11. Flash imaging in dual source CT (DSCT)

    NASA Astrophysics Data System (ADS)

    Bruder, H.; Petersilka, M.; Mehldau, H.; Heidinger, W.; Allmendinger, T.; Schmidt, B.,; Raupach, R.; Thierfelder, C.,; Stierstorfer, K.; Flohr, T.

    2009-02-01

    We present new acquisition modes of a recently introduced dual-source computed tomography (DSCT) system equipped with two X-ray tubes and two corresponding detectors, mounted onto the rotating gantry with an angular offset of typically 90°. Due to the simultaneous acquisition of complementary data, the minimum exposure time is reduced by a factor of two compared to a single-source CT system (SSCT). The correspondingly improved temporal resolution is beneficial for cardiac CT. Also, maximum table feed per rotation in a spiral mode can be increased by a factor of 2 compared to SSCT, which provides benefits both for cardiac CT and non-cardiac CT. In an ECG-triggered mode the entire cardiac volume can be scanned within a fraction of one cardiac RR-cycle. At a rotation time of 0.28s using a detector with 64×0.6 mm beam collimation, the scan time of the entire heart is less than 0.3s at a temporal resolution of 75 ms. It will be shown, that the extremely fast cardiac scan reduces the patient dose to a theoretical lowest limit: for a 120 kV scan the dose level for a typical cardiac CT scan is well below 2 mSv. Using further protocol optimization (scan range adaptation, 100kV), the radiation dose can be reduced below 1mSv.

  12. An active learning approach to the physics of medical imaging.

    PubMed

    Wilhjelm, Jens E; Pihl, Michael Johannes; Lonsdale, Markus Nowak; Jensen, Mikael

    2008-06-01

    This paper describes an experimentally oriented medical imaging course where the students record, process and analyse 3D data of an unknown piece of formalin fixed porcine tissue hidden in agar in order to estimate the tissue types present in a selected 2D slice. The recorded planar X-ray, CT, MRI, ultrasound and SPECT images show the tissue in very different ways. The students can only estimate the tissue type by studying the physical principles of the imaging modalities. The true answer is later revealed by anatomical photographs obtained from physical slicing. The paper describes the phantoms and methods used in the course. Sample images recorded with the different imaging modalities are provided. Challenges faced by the students are outlined. Results of the course show high increase in competencies as judged from graded reports, low course drop-out rate, high pass-rate at the exam, high student participation and large student satisfaction. PMID:17716937

  13. A survey of medical diagnostic imaging technologies

    SciTech Connect

    Heese, V.; Gmuer, N.; Thomlinson, W.

    1991-10-01

    The fields of medical imaging and medical imaging instrumentation are increasingly important. The state-of-the-art continues to advance at a very rapid pace. In fact, various medical imaging modalities are under development at the National Synchrotron Light Source (such as MECT and Transvenous Angiography.) It is important to understand how these techniques compare with today's more conventional imaging modalities. The purpose of this report is to provide some basic information about the various medical imaging technologies currently in use and their potential developments as a basis for this comparison. This report is by no means an in-depth study of the physics and instrumentation of the various imaging modalities; instead, it is an attempt to provide an explanation of the physical bases of these techniques and their principal clinical and research capabilities.

  14. A survey of medical diagnostic imaging technologies

    SciTech Connect

    Heese, V.; Gmuer, N.; Thomlinson, W.

    1991-10-01

    The fields of medical imaging and medical imaging instrumentation are increasingly important. The state-of-the-art continues to advance at a very rapid pace. In fact, various medical imaging modalities are under development at the National Synchrotron Light Source (such as MECT and Transvenous Angiography.) It is important to understand how these techniques compare with today`s more conventional imaging modalities. The purpose of this report is to provide some basic information about the various medical imaging technologies currently in use and their potential developments as a basis for this comparison. This report is by no means an in-depth study of the physics and instrumentation of the various imaging modalities; instead, it is an attempt to provide an explanation of the physical bases of these techniques and their principal clinical and research capabilities.

  15. MR and CT image fusion of the cervical spine: a noninvasive alternative to CT-myelography

    NASA Astrophysics Data System (ADS)

    Hu, Yangqiu; Mirza, Sohail K.; Jarvik, Jeffrey G.; Heagerty, Patrick J.; Haynor, David R.

    2005-04-01

    CT-Myelography (CTM) is routinely used for planning surgery for degenerative disease of the spine, but its invasive nature, significant potential morbidity, and high costs make a noninvasive substitute desirable. We report our work on evaluating CT and MR image fusion as an alternative to CTM. Because the spine is only piecewise rigid, a multi-rigid approach to the registration of spinal CT and MR images was developed (SPIE 2004), in which the spine on CT images is first segmented into separate vertebrae, each of which is then rigidly registered with the corresponding vertebra on MR images. The results are then blended to obtain fusion images. Since they contain information from both modalities, we hypothesized that fusion images would be equivalent to CTM. To test this we selected 34 patients who had undergone MRI and CTM for degenerative disease of the cervical spine, and used the multi-rigid approach to produce fused images. A clinical vignette for each patient was created and presented along with either CT/MR fusion images or CTM images. A group of spine surgeons are asked to formulate detailed surgical plans based on each set of images, and the surgical plans are compared. A similar study assessing diagnostic agreement is being performed with neuroradiologists, who also assess the accuracy of registration. Our work to date has demonstrated the feasibility of segmentation and multi-rigid fusion in clinical cases and the acceptability of the questionnaire to physicians. Preliminary analysis of one surgeon's and one neuroradiologist"s evaluation has been performed.

  16. Development of contrast-enhanced rodent imaging using functional CT

    NASA Astrophysics Data System (ADS)

    Liang, Yun; Stantz, Keith M.; Krishnamurthi, Ganapathy; Steinmetz, Rosemary; Hutchins, Gary D.

    2003-05-01

    Micro-computed tomography (microCT) is capable of obtaining high-resolution images of skeletal tissues. However its image contrast among soft tissues remains inadequate for tumor detection. High speed functional computed tomography will be needed to image tumors by employing x-ray contrast medium. The functional microCT development will not only facilitate the image contrast enhancement among different tissues but also provide information of tumor physiology. To demonstrate the feasibility of functional CT in mouse imaging, sequential computed tomography is performed in mice after contrast material administration using a high-speed clinical CT scanner. Although the resolution of the clinical scanner is not sufficient to dissolve the anatomic details of rodents, bulky physiological parameters in major organs such as liver, kidney, pancreas, and ovaries (testicular) can be examined. For data analysis, a two-compartmental model is employed and implemented to characterize the tissue physiological parameters (regional blood flow, capillary permeability, and relative compartment volumes.) The measured contrast dynamics in kidneys are fitted with the compartmental model to derive the kidney tissue physiology. The study result suggests that it is feasible to extract mouse tissue physiology using functional CT imaging technology.

  17. Constrained TV-minimization image reconstruction for industrial CT system

    NASA Astrophysics Data System (ADS)

    Chen, Buxin; Yang, Min; Zhang, Zheng; Bian, Junguo; Han, Xiao; Sidky, Emil; Pan, Xiaochuan

    2014-02-01

    In this work, we investigate the applicability of the constrained total-variation (TV)-minimization reconstruction method to industrial CT system. In general, industrial CT systems have the same principles of imaging process with clinical CT systems, but different imaging objectives and evaluation metrics. Optimization-based image reconstruction methods have been actively developed to meet practical challenges and extensively tested for clinical CT systems. However, the utility of optimization-based reconstruction methods is task-specific and not necessarily transferrable among different tasks. In this work, we adopt constrained TV-minimization programs together with adaptive-steepest-descent-projection-ontoconvex-sets (ASD-POCS) algorithm for reconstructing images from data of a concrete sample collected using a laboratory industrial CT system developed for non-destructive evaluation. Our results, compared to those reconstructed from FBPbased algorithm, suggest that the constrained TV-minimization program combined with ASD-POCS algorithm can yield images with comparable or improved visual quality and achieve equivalent or better imaging objectives over the currently used FBP-based algorithm under dense sampling data condition.

  18. Implications of CT noise and artifacts for quantitative {sup 99m}Tc SPECT/CT imaging

    SciTech Connect

    Hulme, K. W.; Kappadath, S. C.

    2014-04-15

    Purpose: This paper evaluates the effects of computed tomography (CT) image noise and artifacts on quantitative single-photon emission computed-tomography (SPECT) imaging, with the aim of establishing an appropriate range of CT acquisition parameters for low-dose protocols with respect to accurate SPECT attenuation correction (AC). Methods: SPECT images of two geometric and one anthropomorphic phantom were reconstructed iteratively using CT scans acquired at a range of dose levels (CTDI{sub vol} = 0.4 to 46 mGy). Resultant SPECT image quality was evaluated by comparing mean signal, background noise, and artifacts to SPECT images reconstructed using the highest dose CT for AC. Noise injection was performed on linear-attenuation (μ) maps to determine the CT noise threshold for accurate AC. Results: High levels of CT noise (σ ∼ 200–400 HU) resulted in low μ-maps noise (σ ∼ 1%–3%). Noise levels greater than ∼10% in 140 keV μ-maps were required to produce visibly perceptible increases of ∼15% in {sup 99m}Tc SPECT images. These noise levels would be achieved at low CT dose levels (CTDI{sub vol} = 4 μGy) that are over 2 orders of magnitude lower than the minimum dose for diagnostic CT scanners. CT noise could also lower (bias) the expected μ values. The relative error in reconstructed SPECT signal trended linearly with the relative shift in μ. SPECT signal was, on average, underestimated in regions corresponding with beam-hardening artifacts in CT images. Any process that has the potential to change the CT number of a region by ∼100 HU (e.g., misregistration between CT images and SPECT images due to motion, the presence of contrast in CT images) could introduce errors in μ{sub 140} {sub keV} on the order of 10%, that in turn, could introduce errors on the order of ∼10% into the reconstructed {sup 99m}Tc SPECT image. Conclusions: The impact of CT noise on SPECT noise was demonstrated to be negligible for clinically achievable CT parameters. Because

  19. Borne identity: CT imaging of vascular infections.

    PubMed

    Huang, Jessica S; Ho, Alexander S; Ahmed, Absar; Bhalla, Sanjeev; Menias, Christine O

    2011-08-01

    Vascular infections present in a multitude of ways with computed tomography (CT) aiding in the diagnosis of many of the uncommon vascular infections, which are equally dangerous and carry severe life-threatening consequences if untreated from a delay in diagnosis. This pictorial review aims to discuss and illustrate the CT findings of the following vascular infections including aortitis, mycotic aneurysms, infective endocarditis, septic thrombophlebitis in the chest and abdomen, and Kawasaki disease. Recognition and prompt diagnosis of these uncommon vascular infections are critical to the initiation of the appropriate management and therapy. PMID:21424803

  20. CT and MR imaging after middle ear surgery.

    PubMed

    Kösling, S; Bootz, F

    2001-11-01

    This article describes the current value of imaging in patients after stapes surgery and surgery after chronic otitis media including cholesteatoma. Possibilities and limits of computed tomography (CT) and MRI are described and most important investigation parameters are mentioned. After otosclerosis surgery, CT is the method of first choice in detection of reasons for vertigo and/or recurrent hearing loss in the later postoperative phase. CT may show the position and condition of prosthesis, scarring around the prosthesis and otospongiotic foci. Sometimes, it gives indirect hints for perilymphatic fistulas and incus necrosis. MRI is able to document inner ear complications. CT has a high negative predictive value in cases with a free cavity after mastoidectomy. Localized opacities or total occlusion are difficult to distinguish by CT alone. MRI provides important additional information in the differentiation of cholesterol granuloma, cholesteatoma, effusion, granulation and scar tissue. PMID:11704358

  1. Feature Guided Motion Artifact Reduction with Structure-Awareness in 4D CT Images

    PubMed Central

    Han, Dongfeng; Bayouth, John; Song, Qi; Bhatia, Sudershan; Sonka, Milan; Wu, Xiaodong

    2011-01-01

    In this paper, we propose a novel method to reduce the magnitude of 4D CT artifacts by stitching two images with a data-driven regularization constrain, which helps preserve the local anatomy structures. Our method first computes an interface seam for the stitching in the overlapping region of the first image, which passes through the “smoothest” region, to reduce the structure complexity along the stitching interface. Then, we compute the displacements of the seam by matching the corresponding interface seam in the second image. We use sparse 3D features as the structure cues to guide the seam matching, in which a regularization term is incorporated to keep the structure consistency. The energy function is minimized by solving a multiple-label problem in Markov Random Fields with an anatomical structure preserving regularization term. The displacements are propagated to the rest of second image and the two image are stitched along the interface seams based on the computed displacement field. The method was tested on both simulated data and clinical 4D CT images. The experiments on simulated data demonstrated that the proposed method was able to reduce the landmark distance error on average from 2.9 mm to 1.3 mm, outperforming the registration-based method by about 55%. For clinical 4D CT image data, the image quality was evaluated by three medical experts, and all identified much fewer artifacts from the resulting images by our method than from those by the compared method. PMID:22058647

  2. An extraction algorithm of pulmonary fissures from multislice CT image

    NASA Astrophysics Data System (ADS)

    Tachibana, Hiroyuki; Saita, Shinsuke; Yasutomo, Motokatsu; Kubo, Mitsuru; Kawata, Yoshiki; Niki, Noboru; Nakano, Yasutaka; Sasagawa, Michizo; Eguchi, Kenji; Moriyama, Noriyuki

    2005-04-01

    Aging and smoking history increases number of pulmonary emphysema. Alveoli restoration destroyed by pulmonary emphysema is difficult and early direction is important. Multi-slice CT technology has been improving 3-D image analysis with higher body axis resolution and shorter scan time. And low-dose high accuracy scanning becomes available. Multi-slice CT image helps physicians with accurate measuring but huge volume of the image data takes time and cost. This paper is intended for computer added emphysema region analysis and proves effectiveness of proposed algorithm.

  3. The impact of skull bone intensity on the quality of compressed CT neuro images

    NASA Astrophysics Data System (ADS)

    Kowalik-Urbaniak, Ilona; Vrscay, Edward R.; Wang, Zhou; Cavaro-Menard, Christine; Koff, David; Wallace, Bill; Obara, Boguslaw

    2012-02-01

    The increasing use of technologies such as CT and MRI, along with a continuing improvement in their resolution, has contributed to the explosive growth of digital image data being generated. Medical communities around the world have recognized the need for efficient storage, transmission and display of medical images. For example, the Canadian Association of Radiologists (CAR) has recommended compression ratios for various modalities and anatomical regions to be employed by lossy JPEG and JPEG2000 compression in order to preserve diagnostic quality. Here we investigate the effects of the sharp skull edges present in CT neuro images on JPEG and JPEG2000 lossy compression. We conjecture that this atypical effect is caused by the sharp edges between the skull bone and the background regions as well as between the skull bone and the interior regions. These strong edges create large wavelet coefficients that consume an unnecessarily large number of bits in JPEG2000 compression because of its bitplane coding scheme, and thus result in reduced quality at the interior region, which contains most diagnostic information in the image. To validate the conjecture, we investigate a segmentation based compression algorithm based on simple thresholding and morphological operators. As expected, quality is improved in terms of PSNR as well as the structural similarity (SSIM) image quality measure, and its multiscale (MS-SSIM) and informationweighted (IW-SSIM) versions. This study not only supports our conjecture, but also provides a solution to improve the performance of JPEG and JPEG2000 compression for specific types of CT images.

  4. A curvelet transform approach for the fusion of MR and CT images

    NASA Astrophysics Data System (ADS)

    Ali, F. E.; El-Dokany, I. M.; Saad, A. A.; Abd El-Samie, F. E.

    2010-02-01

    There are several medical imaging techniques such as the magnetic resonance (MR) and the computed tomography (CT) techniques. Both techniques give sophisticated characteristics of the region to be imaged. This paper proposes a curvelet based approach for fusing MR and CT images to obtain images with as much detail as possible, for the sake of medical diagnosis. This approach is based on the application of the additive wavelet transform (AWT) on both images and the segmentation of their detail planes into small overlapping tiles. The ridgelet transform is then applied on each of these tiles, and the fusion process is performed on the ridgelet transforms of the tiles. Simulation results show the superiority of the proposed curvelet fusion approach to the traditional fusion techniques like the multiresolution discrete wavelet transform (DWT) technique and the principal component analysis (PCA) technique. The fusion of MR and CT images in the presence of noise is also studied and the results reveal that unlike the DWT fusion technique, the proposed curvelet fusion approach doesn't require denoising.

  5. Research on THz CT system and image reconstruction algorithm

    NASA Astrophysics Data System (ADS)

    Li, Ming-liang; Wang, Cong; Cheng, Hong

    2009-07-01

    Terahertz Computed Tomography takes the advantages of not only high resolution in space and density without image overlap but also the capability of being directly used in digital processing and spectral analysis, which determine it to be a good choice in parameter detection for process control. But Diffraction and scattering of THz wave will obfuscate or distort the reconstructed image. In order to find the most effective reconstruction method to build THz CT model. Because of the expensive cost, a fan-shaped THz CT industrial detection system scanning model, which consists of 8 emitters and 32 receivers, is established based on studying infrared CT technology. The model contains control and interface, data collecting and image reconstruction sub-system. It analyzes all the sub-function modules then reconstructs images with algebraic reconstruction algorithm. The experimental result proves it to be an effective, efficient algorithm with high resolution and even better than back-projection method.

  6. Content-Based Medical Image Retrieval

    NASA Astrophysics Data System (ADS)

    Müller, Henning; Deserno, Thomas M.

    This chapter details the necessity for alternative access concepts to the currently mainly text-based methods in medical information retrieval. This need is partly due to the large amount of visual data produced, the increasing variety of medical imaging data and changing user patterns. The stored visual data contain large amounts of unused information that, if well exploited, can help diagnosis, teaching and research. The chapter briefly reviews the history of image retrieval and its general methods before technologies that have been developed in the medical domain are focussed. We also discuss evaluation of medical content-based image retrieval (CBIR) systems and conclude with pointing out their strengths, gaps, and further developments. As examples, the MedGIFT project and the Image Retrieval in Medical Applications (IRMA) framework are presented.

  7. CT imaging findings of a calcifying epithelial odontogenic tumour

    PubMed Central

    Venkateswarlu, M; Geetha, P; Lakshmi Kavitha, N

    2012-01-01

    We report a case of calcifying epithelial odontogenic tumour (CEOT), also known as a Pindborg tumour, with local aggressive behaviour. CT imaging showed a large expansile bone-forming lesion in the mandible, which showed the exact extent and nature of the lesion. We briefly discuss the imaging features of CEOT and the relevant literature. PMID:22190756

  8. CT guided diffuse optical tomography for breast cancer imaging

    NASA Astrophysics Data System (ADS)

    Baikejiang, Reheman; Zhang, Wei; Zhu, Dianwen; Li, Changqing

    2016-03-01

    Diffuse optical tomography (DOT) has attracted attentions in the last two decades due to its intrinsic sensitivity in imaging chromophores of tissues such as blood, water, and lipid. However, DOT has not been clinically accepted yet due to its low spatial resolution caused by strong optical scattering in tissues. Structural guidance provided by an anatomical imaging modality enhances the DOT imaging substantially. Here, we propose a computed tomography (CT) guided multispectral DOT imaging system for breast cancer detection. To validate its feasibility, we have built a prototype DOT imaging system which consists of a laser at wavelengths of 650 and an electron multiplying charge coupled device (EMCCD) camera. We have validated the CT guided DOT reconstruction algorithms with numerical simulations and phantom experiments, in which different imaging setup parameters, such as projection number of measurements, the width of measurement patch, have been investigated. Our results indicate that an EMCCD camera with air cooling is good enough for the transmission mode DOT imaging. We have also found that measurements at six projections are sufficient for DOT to reconstruct the optical targets with 4 times absorption contrast when the CT guidance is applied. Finally, we report our effort and progress on the integration of the multispectral DOT imaging system into a breast CT scanner.

  9. Multimodality medical image fusion: probabilistic quantification, segmentation, and registration

    NASA Astrophysics Data System (ADS)

    Wang, Yue J.; Freedman, Matthew T.; Xuan, Jian Hua; Zheng, Qinfen; Mun, Seong K.

    1998-06-01

    Multimodality medical image fusion is becoming increasingly important in clinical applications, which involves information processing, registration and visualization of interventional and/or diagnostic images obtained from different modalities. This work is to develop a multimodality medical image fusion technique through probabilistic quantification, segmentation, and registration, based on statistical data mapping, multiple feature correlation, and probabilistic mean ergodic theorems. The goal of image fusion is to geometrically align two or more image areas/volumes so that pixels/voxels representing the same underlying anatomical structure can be superimposed meaningfully. Three steps are involved. To accurately extract the regions of interest, we developed the model supported Bayesian relaxation labeling, and edge detection and region growing integrated algorithms to segment the images into objects. After identifying the shift-invariant features (i.e., edge and region information), we provided an accurate and robust registration technique which is based on matching multiple binary feature images through a site model based image re-projection. The image was initially segmented into specified number of regions. A rough contour can be obtained by delineating and merging some of the segmented regions. We applied region growing and morphological filtering to extract the contour and get rid of some disconnected residual pixels after segmentation. The matching algorithm is implemented as follows: (1) the centroids of PET/CT and MR images are computed and then translated to the center of both images. (2) preliminary registration is performed first to determine an initial range of scaling factors and rotations, and the MR image is then resampled according to the specified parameters. (3) the total binary difference of the corresponding binary maps in both images is calculated for the selected registration parameters, and the final registration is achieved when the

  10. Denoising Medical Images using Calculus of Variations

    PubMed Central

    Kohan, Mahdi Nakhaie; Behnam, Hamid

    2011-01-01

    We propose a method for medical image denoising using calculus of variations and local variance estimation by shaped windows. This method reduces any additive noise and preserves small patterns and edges of images. A pyramid structure-texture decomposition of images is used to separate noise and texture components based on local variance measures. The experimental results show that the proposed method has visual improvement as well as a better SNR, RMSE and PSNR than common medical image denoising methods. Experimental results in denoising a sample Magnetic Resonance image show that SNR, PSNR and RMSE have been improved by 19, 9 and 21 percents respectively. PMID:22606674

  11. Medical image analysis with artificial neural networks.

    PubMed

    Jiang, J; Trundle, P; Ren, J

    2010-12-01

    Given that neural networks have been widely reported in the research community of medical imaging, we provide a focused literature survey on recent neural network developments in computer-aided diagnosis, medical image segmentation and edge detection towards visual content analysis, and medical image registration for its pre-processing and post-processing, with the aims of increasing awareness of how neural networks can be applied to these areas and to provide a foundation for further research and practical development. Representative techniques and algorithms are explained in detail to provide inspiring examples illustrating: (i) how a known neural network with fixed structure and training procedure could be applied to resolve a medical imaging problem; (ii) how medical images could be analysed, processed, and characterised by neural networks; and (iii) how neural networks could be expanded further to resolve problems relevant to medical imaging. In the concluding section, a highlight of comparisons among many neural network applications is included to provide a global view on computational intelligence with neural networks in medical imaging. PMID:20713305

  12. Objective index of image fidelity for JPEG2000 compressed body CT images

    SciTech Connect

    Kim, Kil Joong; Lee, Kyoung Ho; Kang, Heung-Sik; Kim, So Yeon; Kim, Young Hoon; Kim, Bohyoung; Seo, Jinwook; Mantiuk, Rafal

    2009-07-15

    Compression ratio (CR) has been the de facto standard index of compression level for medical images. The aim of the study is to evaluate the CR, peak signal-to-noise ratio (PSNR), and a perceptual quality metric (high-dynamic range visual difference predictor HDR-VDP) as objective indices of image fidelity for Joint Photographic Experts Group (JPEG) 2000 compressed body computed tomography (CT) images, from the viewpoint of visually lossless compression approach. A total of 250 body CT images obtained with five different scan protocols (5-mm-thick abdomen, 0.67-mm-thick abdomen, 5-mm-thick lung, 0.67-mm-thick lung, and 5-mm-thick low-dose lung) were compressed to one of five CRs (reversible, 6:1, 8:1, 10:1, and 15:1). The PSNR and HDR-VDP values were calculated for the 250 pairs of the original and compressed images. By alternately displaying an original and its compressed image on the same monitor, five radiologists independently determined if the pair was distinguishable or indistinguishable. The kappa statistic for the interobserver agreement among the five radiologists' responses was 0.70. According to the radiologists' responses, the number of distinguishable image pairs tended to significantly differ among the five scan protocols at 6:1-10:1 compressions (Fisher-Freeman-Halton exact tests). Spearman's correlation coefficients between each of the CR, PSNR, and HDR-VDP and the number of radiologists who responded as distinguishable were 0.72, -0.77, and 0.85, respectively. Using the radiologists' pooled responses as the reference standards, the areas under the receiver-operating-characteristic curves for the CR, PSNR, and HDR-VDP were 0.87, 0.93, and 0.97, respectively, showing significant differences between the CR and PSNR (p=0.04), or HDR-VDP (p<0.001), and between the PSNR and HDR-VDP (p<0.001). In conclusion, the CR is less suitable than the PSNR or HDR-VDP as an objective index of image fidelity for JPEG2000 compressed body CT images. The HDR-VDP is more

  13. Autoradiographic image intensification - Applications in medical radiography

    NASA Technical Reports Server (NTRS)

    Askins, B. S.

    1978-01-01

    The image of an 80 to 90 percent underexposed medical radiograph can be increased to readable density and contrast by autoradiographic image intensification. The technique consists of combining the image silver of the radiograph with a radioactive compound, thiourea labeled with sulfur-35, and then making an autoradiograph from the activated negative.

  14. A simple method for labeling CT images with respiratory states

    SciTech Connect

    Berlinger, Kajetan; Sauer, Otto; Vences, Lucia; Roth, Michael

    2006-09-15

    A method is described for labeling CT images with their respiratory state by a needle, connected to the patient's chest/abdomen. By means of a leverage the needle follows the abdominal respiratory motion. The needle is visible as a blurred spot in every CT slice. The method was tested with nine patients. A series of volume scans during free breathing was performed. The detected positions of the moving needle in every single slice were compared to each other thus enabling respiratory state assignment. The tool is an inexpensive alternative to complex respiratory measuring tools for four dimensional (4D) CT and was greatly accepted in the clinic due to its simplicity.

  15. Vision 20/20: Single photon counting x-ray detectors in medical imaging

    PubMed Central

    Taguchi, Katsuyuki; Iwanczyk, Jan S.

    2013-01-01

    Photon counting detectors (PCDs) with energy discrimination capabilities have been developed for medical x-ray computed tomography (CT) and x-ray (XR) imaging. Using detection mechanisms that are completely different from the current energy integrating detectors and measuring the material information of the object to be imaged, these PCDs have the potential not only to improve the current CT and XR images, such as dose reduction, but also to open revolutionary novel applications such as molecular CT and XR imaging. The performance of PCDs is not flawless, however, and it seems extremely challenging to develop PCDs with close to ideal characteristics. In this paper, the authors offer our vision for the future of PCD-CT and PCD-XR with the review of the current status and the prediction of (1) detector technologies, (2) imaging technologies, (3) system technologies, and (4) potential clinical benefits with PCDs. PMID:24089889

  16. Adaptively Tuned Iterative Low Dose CT Image Denoising

    PubMed Central

    Hashemi, SayedMasoud; Paul, Narinder S.; Beheshti, Soosan; Cobbold, Richard S. C.

    2015-01-01

    Improving image quality is a critical objective in low dose computed tomography (CT) imaging and is the primary focus of CT image denoising. State-of-the-art CT denoising algorithms are mainly based on iterative minimization of an objective function, in which the performance is controlled by regularization parameters. To achieve the best results, these should be chosen carefully. However, the parameter selection is typically performed in an ad hoc manner, which can cause the algorithms to converge slowly or become trapped in a local minimum. To overcome these issues a noise confidence region evaluation (NCRE) method is used, which evaluates the denoising residuals iteratively and compares their statistics with those produced by additive noise. It then updates the parameters at the end of each iteration to achieve a better match to the noise statistics. By combining NCRE with the fundamentals of block matching and 3D filtering (BM3D) approach, a new iterative CT image denoising method is proposed. It is shown that this new denoising method improves the BM3D performance in terms of both the mean square error and a structural similarity index. Moreover, simulations and patient results show that this method preserves the clinically important details of low dose CT images together with a substantial noise reduction. PMID:26089972

  17. A modified VMAT adaptive radiotherapy for nasopharyngeal cancer patients based on CT-CT image fusion

    PubMed Central

    2013-01-01

    Background To investigate the feasibility and benefits of a modified adaptive radiotherapy (ART) by replanning in the initial CT (iCT) with new contours from a repeat CT (rCT) based on CT-CT image fusion for nasopharyngeal cancer (NPC) patients underwent volumetric modulated arc radiotherapy (VMAT). Materials and methods Nine NPC patients underwent VMAT treatment with a rCT at 23rd fraction were enrolled in this study. Dosimetric differences for replanning VMAT plans in the iCT and in the rCT were compared. Volumetric and dosimetric changes of gross tumor volume (GTV) and organs at risk (OARs) of this modified ART were also investigated. Results No dosimetric differences between replanning in the iCT and in the rCT were observed. The average volume of GTV decreased from 78.83 ± 38.42 cm3 in the iCT to 71.44 ± 37.46 cm3 in the rCT, but with no significant difference (p = 0.42).The average volume of the left and right parotid decreased from 19.91 ± 4.89 cm3 and 21.58 ± 6.16 cm3 in the iCT to 11.80 ± 2.79 cm3 and 13.29 ± 4.17 cm3 in the rCT (both p < 0.01), respectively. The volume of other OARs did not shrink very much. No significant differences on PTVGTV and PTVCTV coverage were observed for replanning with this modified ART. Compared to the initial plans, the average mean dose of the left and right parotid after re-optimization were decreased by 62.5 cGy (p = 0.05) and 67.3 cGy (p = 0.02), respectively, and the V5 (the volume receiving 5 Gy) of the left and right parotids were decreased by 7.8% (p = 0.01) and 11.2% (p = 0.001), respectively. There was no significant difference on the dose delivered to other OARs. Conclusion Patients with NPC undergoing VMAT have significant anatomic and dosimetric changes to parotids. Repeat CT as an anatomic changes reference and re-optimization in the iCT based on CT-CT image fusion was accurate enough to identify the volume changes and to ensure safe dose to

  18. Prototype 1.75 MV X-band linear accelerator testing for medical CT and industrial nondestructive testing applications

    NASA Astrophysics Data System (ADS)

    Clayton, James; Shedlock, Daniel; Vanderet, Steven; Zentai, George; Star-Lack, Josh; LaFave, Richard; Virshup, Gary

    2015-03-01

    Flat panel imagers based on amorphous silicon technology (a-Si) for digital radiography are accepted by the medical and industrial community as having several advantages over radiographic film-based systems. Use of Mega-voltage x-rays with these flat panel systems is applicable to both portal imaging for radiotherapy and for nondestructive testing (NDT) and security applications. In the medical field, one potential application that has not been greatly explored is to radiotherapy treatment planning. Currently, such conventional computed tomographic (CT) data acquired at kV energies is used to help delineate tumor targets and normal structures that are to be spared during treatment. CT number accuracy is crucial for radiotherapy dose calculations. Conventional CT scanners operating at kV X-ray energies typically exhibit significant image reconstruction artifacts in the presence of metal implants in human body. Using the X-ray treatment beams, having energies typically >=6MV, to acquire the CT data may not be practical if it is desired to maintain contrast sensitivity at a sufficiently low dose. Nondestructive testing imaging systems can expand their application space with the development of the higher energy accelerator for use in pipeline, and casting inspection as well as certain cargo screening applications that require more penetration. A new prototype x-band BCL designed to operate up to 1.75 MV has been designed built and tested. The BCL was tested with a prototype portal imager and medical phantoms to determine artifact reductions and a PaxScan 2530HE industrial imager to demonstrate resolution is maintained and penetration is improved.

  19. Efficient iterative image reconstruction algorithm for dedicated breast CT

    NASA Astrophysics Data System (ADS)

    Antropova, Natalia; Sanchez, Adrian; Reiser, Ingrid S.; Sidky, Emil Y.; Boone, John; Pan, Xiaochuan

    2016-03-01

    Dedicated breast computed tomography (bCT) is currently being studied as a potential screening method for breast cancer. The X-ray exposure is set low to achieve an average glandular dose comparable to that of mammography, yielding projection data that contains high levels of noise. Iterative image reconstruction (IIR) algorithms may be well-suited for the system since they potentially reduce the effects of noise in the reconstructed images. However, IIR outcomes can be difficult to control since the algorithm parameters do not directly correspond to the image properties. Also, IIR algorithms are computationally demanding and have optimal parameter settings that depend on the size and shape of the breast and positioning of the patient. In this work, we design an efficient IIR algorithm with meaningful parameter specifications and that can be used on a large, diverse sample of bCT cases. The flexibility and efficiency of this method comes from having the final image produced by a linear combination of two separately reconstructed images - one containing gray level information and the other with enhanced high frequency components. Both of the images result from few iterations of separate IIR algorithms. The proposed algorithm depends on two parameters both of which have a well-defined impact on image quality. The algorithm is applied to numerous bCT cases from a dedicated bCT prototype system developed at University of California, Davis.

  20. Multiscale registration of planning CT and daily cone beam CT images for adaptive radiation therapy

    SciTech Connect

    Paquin, Dana; Levy, Doron; Xing Lei

    2009-01-15

    Adaptive radiation therapy (ART) is the incorporation of daily images in the radiotherapy treatment process so that the treatment plan can be evaluated and modified to maximize the amount of radiation dose to the tumor while minimizing the amount of radiation delivered to healthy tissue. Registration of planning images with daily images is thus an important component of ART. In this article, the authors report their research on multiscale registration of planning computed tomography (CT) images with daily cone beam CT (CBCT) images. The multiscale algorithm is based on the hierarchical multiscale image decomposition of E. Tadmor, S. Nezzar, and L. Vese [Multiscale Model. Simul. 2(4), pp. 554-579 (2004)]. Registration is achieved by decomposing the images to be registered into a series of scales using the (BV, L{sup 2}) decomposition and initially registering the coarsest scales of the image using a landmark-based registration algorithm. The resulting transformation is then used as a starting point to deformably register the next coarse scales with one another. This procedure is iterated at each stage using the transformation computed by the previous scale registration as the starting point for the current registration. The authors present the results of studies of rectum, head-neck, and prostate CT-CBCT registration, and validate their registration method quantitatively using synthetic results in which the exact transformations our known, and qualitatively using clinical deformations in which the exact results are not known.

  1. An efficient medical image compression scheme.

    PubMed

    Li, Xiaofeng; Shen, Yi; Ma, Jiachen

    2005-01-01

    In this paper, a fast lossless compression scheme is presented for the medical image. This scheme consists of two stages. In the first stage, a Differential Pulse Code Modulation (DPCM) is used to decorrelate the raw image data, therefore increasing the compressibility of the medical image. In the second stage, an effective scheme based on the Huffman coding method is developed to encode the residual image. This newly proposed scheme could reduce the cost for the Huffman coding table while achieving high compression ratio. With this algorithm, a compression ratio higher than that of the lossless JPEG method for image can be obtained. At the same time, this method is quicker than the lossless JPEG2000. In other words, the newly proposed algorithm provides a good means for lossless medical image compression. PMID:17280962

  2. THz Medical Imaging: in vivo Hydration Sensing

    PubMed Central

    Taylor, Zachary D.; Singh, Rahul S.; Bennett, David B.; Tewari, Priyamvada; Kealey, Colin P.; Bajwa, Neha; Culjat, Martin O.; Stojadinovic, Alexander; Lee, Hua; Hubschman, Jean-Pierre; Brown, Elliott R.; Grundfest, Warren S.

    2015-01-01

    The application of THz to medical imaging is experiencing a surge in both interest and federal funding. A brief overview of the field is provided along with promising and emerging applications and ongoing research. THz imaging phenomenology is discussed and tradeoffs are identified. A THz medical imaging system, operating at ~525 GHz center frequency with ~125 GHz of response normalized bandwidth is introduced and details regarding principles of operation are provided. Two promising medical applications of THz imaging are presented: skin burns and cornea. For burns, images of second degree, partial thickness burns were obtained in rat models in vivo over an 8 hour period. These images clearly show the formation and progression of edema in and around the burn wound area. For cornea, experimental data measuring the hydration of ex vivo porcine cornea under drying is presented demonstrating utility in ophthalmologic applications. PMID:26085958

  3. CT Angiography (CTA)

    MedlinePlus

    ... CT Angiography? Angiography is a minimally invasive medical test that helps physicians diagnose and treat medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ...

  4. Quantitative imaging of electron density and effective atomic number using phase contrast CT

    NASA Astrophysics Data System (ADS)

    Qi, Zhihua; Zambelli, Joseph; Bevins, Nicholas; Chen, Guang-Hong

    2010-05-01

    Compared to single energy CT, which only provides information for x-ray linear attenuation coefficients, dual-energy CT is able to obtain both the electron density and effective atomic number for different materials in a quantitative way. In this study, as an alternative to dual-energy CT, a novel quantitative imaging method based on phase contrast CT is presented. Rather than requiring two projection data sets with different x-ray energy spectra, diffraction-grating-based phase contrast CT is capable of reconstructing images of both linear attenuation and refractive index decrement from the same projection data using a single x-ray energy spectra. From the two images, quantitative information of both the electron density and effective atomic number can be extracted. Two physical phantoms were constructed and used to validate the presented method. Experimental results demonstrate that (1) electron density can be accurately determined from refractive index decrement through a linear relationship, and (2) the effective atomic number can be explicitly derived from the ratio of the linear attenuation to refractive index decrement using a power function plus a constant. The presented method will provide insight into the technique of material separation and find its use in medical and industrial applications.

  5. PET/CT (and CT) instrumentation, image reconstruction and data transfer for radiotherapy planning.

    PubMed

    Sattler, Bernhard; Lee, John A; Lonsdale, Markus; Coche, Emmanuel

    2010-09-01

    The positron emission tomography in combination with CT in hybrid, cross-modality imaging systems (PET/CT) gains more and more importance as a part of the treatment-planning procedure in radiotherapy. Positron emission tomography (PET), as a integral part of nuclear medicine imaging and non-invasive imaging technique, offers the visualization and quantification of pre-selected tracer metabolism. In combination with the structural information from CT, this molecular imaging technique has great potential to support and improve the outcome of the treatment-planning procedure prior to radiotherapy. By the choice of the PET-Tracer, a variety of different metabolic processes can be visualized. First and foremost, this is the glucose metabolism of a tissue as well as for instance hypoxia or cell proliferation. This paper comprises the system characteristics of hybrid PET/CT systems. Acquisition and processing protocols are described in general and modifications to cope with the special needs in radiooncology. This starts with the different position of the patient on a special table top, continues with the use of the same fixation material as used for positioning of the patient in radiooncology while simulation and irradiation and leads to special processing protocols that include the delineation of the volumes that are subject to treatment planning and irradiation (PTV, GTV, CTV, etc.). General CT acquisition and processing parameters as well as the use of contrast enhancement of the CT are described. The possible risks and pitfalls the investigator could face during the hybrid-imaging procedure are explained and listed. The interdisciplinary use of different imaging modalities implies a increase of the volume of data created. These data need to be stored and communicated fast, safe and correct. Therefore, the DICOM-Standard provides objects and classes for this purpose (DICOM RT). Furthermore, the standard DICOM objects and classes for nuclear medicine (NM, PT) and

  6. [Medical tele-imaging: a good chance for the future].

    PubMed

    Bonnin, A

    1999-01-01

    Tele-imaging is an important part of telemedicine: it includes the transmission of medical digital images and plays a role in all fields of telemedicine, such as expertise, consultation, teaching and research. Tele-imaging has been made possible through the digitalization of medical imaging. There are two possibilities: either digitalization of conventional radiological film or direct acquisition of digital images. The transmission of medical imaging requires a high data rate so as to obtain a good quality transmission of the initial images in a reasonable delay. In order to deal with the great amount of information to be stocked and transmitted, a compression of the data, without loss of information, is usually necessary. Interactivity is very important in all these types of transmissions. These tele-transmission techniques are already used world wide, especially in Japan and in the United States, to help in therapeutic or diagnostic decisions. In France, we have been performing real time interactive tele-imaging sessions between radiology and endocrinology departments of Hotel Dieu in Montréal and Hôpital Cochin in Paris. This experimental device includes a visual-conference link between the medical teams and a real time link between two CT scanners. The CT scanner slices appear simultaneously both CT scanner screens; it is even possible to guide a CT scanner examination using remote control from the other hospital. We have successfully repeated the experiment between Cochin and a private hospital in Paris. In the case of the "Prison de la Santé", we have been using telemedicine in order to reduce problematic transfers of prison inmates. Moreover, access to doctors in the prison is sometimes difficult. The system ensures the daily transmission of X-rays, which are immediately read by radiologists at Cochin. In the past, 50 to 70 X-rays had to be read during one weekly visit. Medical tele-imaging raises certain legal, ethical and economic issues, such as

  7. Liver recognition based on statistical shape model in CT images

    NASA Astrophysics Data System (ADS)

    Xiang, Dehui; Jiang, Xueqing; Shi, Fei; Zhu, Weifang; Chen, Xinjian

    2016-03-01

    In this paper, an automatic method is proposed to recognize the liver on clinical 3D CT images. The proposed method effectively use statistical shape model of the liver. Our approach consist of three main parts: (1) model training, in which shape variability is detected using principal component analysis from the manual annotation; (2) model localization, in which a fast Euclidean distance transformation based method is able to localize the liver in CT images; (3) liver recognition, the initial mesh is locally and iteratively adapted to the liver boundary, which is constrained with the trained shape model. We validate our algorithm on a dataset which consists of 20 3D CT images obtained from different patients. The average ARVD was 8.99%, the average ASSD was 2.69mm, the average RMSD was 4.92mm, the average MSD was 28.841mm, and the average MSD was 13.31%.

  8. Image registration method for medical image sequences

    DOEpatents

    Gee, Timothy F.; Goddard, James S.

    2013-03-26

    Image registration of low contrast image sequences is provided. In one aspect, a desired region of an image is automatically segmented and only the desired region is registered. Active contours and adaptive thresholding of intensity or edge information may be used to segment the desired regions. A transform function is defined to register the segmented region, and sub-pixel information may be determined using one or more interpolation methods.

  9. Allergic reactions to medication (image)

    MedlinePlus

    A true allergy to a medication is different than a simple adverse reaction to the drug. The allergic reaction occurs when the immune system, having been exposed to the drug before, creates antibodies to ...

  10. Automated delineation of stroke lesions using brain CT images

    PubMed Central

    Gillebert, Céline R.; Humphreys, Glyn W.; Mantini, Dante

    2014-01-01

    Computed tomographic (CT) images are widely used for the identification of abnormal brain tissue following infarct and hemorrhage in stroke. Manual lesion delineation is currently the standard approach, but is both time-consuming and operator-dependent. To address these issues, we present a method that can automatically delineate infarct and hemorrhage in stroke CT images. The key elements of this method are the accurate normalization of CT images from stroke patients into template space and the subsequent voxelwise comparison with a group of control CT images for defining areas with hypo- or hyper-intense signals. Our validation, using simulated and actual lesions, shows that our approach is effective in reconstructing lesions resulting from both infarct and hemorrhage and yields lesion maps spatially consistent with those produced manually by expert operators. A limitation is that, relative to manual delineation, there is reduced sensitivity of the automated method in regions close to the ventricles and the brain contours. However, the automated method presents a number of benefits in terms of offering significant time savings and the elimination of the inter-operator differences inherent to manual tracing approaches. These factors are relevant for the creation of large-scale lesion databases for neuropsychological research. The automated delineation of stroke lesions from CT scans may also enable longitudinal studies to quantify changes in damaged tissue in an objective and reproducible manner. PMID:24818079

  11. The evolution of PET-CT.

    PubMed

    Wilson, Bettye G

    2005-01-01

    Positron emission tomography-computed tomography (PET-CT) was the first fused or combined medical imaging technique. Although PET-CT has received widespread acclaim as a major imaging advancement, many questions have surfaced regarding its use. This article answers some of these questions and examines what PET-CT means to medicine and the medical imaging community. PMID:15835615

  12. Computer-aided diagnosis workstation and database system for chest diagnosis based on multi-helical CT images

    NASA Astrophysics Data System (ADS)

    Satoh, Hitoshi; Niki, Noboru; Mori, Kiyoshi; Eguchi, Kenji; Kaneko, Masahiro; Kakinuma, Ryutarou; Moriyama, Noriyuki; Ohmatsu, Hironobu; Masuda, Hideo; Machida, Suguru; Sasagawa, Michizou

    2006-03-01

    Multi-helical CT scanner advanced remarkably at the speed at which the chest CT images were acquired for mass screening. Mass screening based on multi-helical CT images requires a considerable number of images to be read. It is this time-consuming step that makes the use of helical CT for mass screening impractical at present. To overcome this problem, we have provided diagnostic assistance methods to medical screening specialists by developing a lung cancer screening algorithm that automatically detects suspected lung cancers in helical CT images and a coronary artery calcification screening algorithm that automatically detects suspected coronary artery calcification. We also have developed electronic medical recording system and prototype internet system for the community health in two or more regions by using the Virtual Private Network router and Biometric fingerprint authentication system and Biometric face authentication system for safety of medical information. Based on these diagnostic assistance methods, we have now developed a new computer-aided workstation and database that can display suspected lesions three-dimensionally in a short time. This paper describes basic studies that have been conducted to evaluate this new system. The results of this study indicate that our computer-aided diagnosis workstation and network system can increase diagnostic speed, diagnostic accuracy and safety of medical information.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  14. Three-dimensional dental imaging by spiral CT

    NASA Astrophysics Data System (ADS)

    Vannier, Michael W.; Hildebolt, Charles F.; Conover, Gary; Knapp, Robert H.; Yokoyama-Crothers, Naoko; Wang, Ge

    1995-05-01

    Three-dimensional image acquisition, display, and analysis of dental structures was performed and validated using spiral computed tomography (SCT) with metal artifact suppression. Isolated extracted teeth, a dry mandible, cadaver mandible, and cadaver head were scanned and reconstructed using a spiral CT scanner (Siemens Somatom PLUS-S) with 1 mm detector collimation, 1-mm table feed, and 0.1 - 1 mm reconstruction interval using specially developed software. Algorithms for metal artifact reduction including extended attenuation range and interpolation of missing projections were applied. Volumetric rendering of voxel sum images was performed to synthesize images comparable to conventional intraoral dental radiographs. Direct comparison of voxel-based synthetic and digitized film images was made. Several isolated, extracted teeth were sectioned with a diamond saw and submitted for histomorphometric analysis to aid in direct comparison with CT slice images obtained by multiplanar reconstruction. Metal artifact reduction was successful in markedly reducing the streaks and star patterns that usually accompany metallic restorations and intraoral appliances. Individual teeth were comparable to CT slice images. Voxel sum images were comparable to dental radiographs; however, for the SCT images, the spatial resolution was higher within the plane of section than it was orthogonal to the plane of section. Serial examinations were obtained by SCT, registered by surface matching, and interval change measured by 3D subtraction. Simulated lesions and restorations were introduced and quantitatively evaluated pre- and post-interventionally to assess imaging method performance.

  15. Computer-aided diagnosis workstation for chest diagnosis based on multihelical CT images

    NASA Astrophysics Data System (ADS)

    Sato, Hitoshi; Niki, Noboru; Mori, Kiyoshi; Eguchi, Kenji; Kaneko, Masahiro; Kakinuma, Ryutarou; Moriyama, Noriyuki; Ohmatsu, Hironobu; Masuda, Hideo; Machida, Suguru; Sasagawa, Michizou

    2005-04-01

    Mass screening based on helical CT images requires a considerable number of images to be read. It is this time-consuming step that makes the use of helical CT for mass screening impractical at present. To overcome this problem, we have provided diagnostic assistance methods to medical screening specialists by developing a lung cancer screening algorithm that automatically detects suspected lung cancers in helical CT images and a coronary artery calcification screening algorithm that automatically detects suspected coronary artery calcification. We also have developed electronic medical recording system and prototype internet system for the community health in two or more regions by using the Virtual Private Network router. This electronic medical recording system and prototype internet system were developed so as not to loosen the communication among staffs of hospital. Based on these diagnostic assistance methods, we have now developed a new computer-aided workstation and database that can display suspected lesions three-dimensionally in a short time. This paper describes basic studies that have been conducted to evaluate this new system.

  16. Web-based medical image archive system

    NASA Astrophysics Data System (ADS)

    Suh, Edward B.; Warach, Steven; Cheung, Huey; Wang, Shaohua A.; Tangiral, Phanidral; Luby, Marie; Martino, Robert L.

    2002-05-01

    This paper presents a Web-based medical image archive system in three-tier, client-server architecture for the storage and retrieval of medical image data, as well as patient information and clinical data. The Web-based medical image archive system was designed to meet the need of the National Institute of Neurological Disorders and Stroke for a central image repository to address questions of stroke pathophysiology and imaging biomarkers in stroke clinical trials by analyzing images obtained from a large number of clinical trials conducted by government, academic and pharmaceutical industry researchers. In the database management-tier, we designed the image storage hierarchy to accommodate large binary image data files that the database software can access in parallel. In the middle-tier, a commercial Enterprise Java Bean server and secure Web server manages user access to the image database system. User-friendly Web-interfaces and applet tools are provided in the client-tier for easy access to the image archive system over the Internet. Benchmark test results show that our three-tier image archive system yields fast system response time for uploading, downloading, and querying the image database.

  17. Dedicated Cone-Beam CT System for Extremity Imaging

    PubMed Central

    Al Muhit, Abdullah; Zbijewski, Wojciech; Thawait, Gaurav K.; Stayman, J. Webster; Packard, Nathan; Senn, Robert; Yang, Dong; Foos, David H.; Yorkston, John; Siewerdsen, Jeffrey H.

    2014-01-01

    Purpose To provide initial assessment of image quality and dose for a cone-beam computed tomographic (CT) scanner dedicated to extremity imaging. Materials and Methods A prototype cone-beam CT scanner has been developed for imaging the extremities, including the weight-bearing lower extremities. Initial technical assessment included evaluation of radiation dose measured as a function of kilovolt peak and tube output (in milliampere seconds), contrast resolution assessed in terms of the signal difference–to-noise ratio (SDNR), spatial resolution semiquantitatively assessed by using a line-pair module from a phantom, and qualitative evaluation of cadaver images for potential diagnostic value and image artifacts by an expert CT observer (musculoskeletal radiologist). Results The dose for a nominal scan protocol (80 kVp, 108 mAs) was 9 mGy (absolute dose measured at the center of a CT dose index phantom). SDNR was maximized with the 80-kVp scan technique, and contrast resolution was sufficient for visualization of muscle, fat, ligaments and/or tendons, cartilage joint space, and bone. Spatial resolution in the axial plane exceeded 15 line pairs per centimeter. Streaks associated with x-ray scatter (in thicker regions of the patient—eg, the knee), beam hardening (about cortical bone—eg, the femoral shaft), and cone-beam artifacts (at joint space surfaces oriented along the scanning plane—eg, the interphalangeal joints) presented a slight impediment to visualization. Cadaver images (elbow, hand, knee, and foot) demonstrated excellent visibility of bone detail and good soft-tissue visibility suitable to a broad spectrum of musculoskeletal indications. Conclusion A dedicated extremity cone-beam CT scanner capable of imaging upper and lower extremities (including weight-bearing examinations) provides sufficient image quality and favorable dose characteristics to warrant further evaluation for clinical use. © RSNA, 2013 Online supplemental material is available for

  18. Study warns of radiation risk in medical imaging

    NASA Astrophysics Data System (ADS)

    Gwynne, Peter

    2009-10-01

    A study of a million US patients suggests that some who undergo medical imaging could be exposed to more ionizing radiation than those who work with radioactive materials in nuclear power plants. The study, reported in The New England Journal of Medicine (361 849), implies that current exposure to radiation from conventional X-ray equipment as well as computed tomography (CT) and positron-emission tomography (PET) scanners could lead to tens of thousands of extra cases of cancer in the US alone.

  19. Utilization of CT images for the quantification of FDG uptake

    NASA Astrophysics Data System (ADS)

    Karidioula, I.; De Freitas, D.; Cachin, F.; Geissler, B.; Jullien, Ph.; Maublant, J.

    2006-12-01

    The aim of this study was to evaluate an automatic method based on a computed tomography (CT) derived region of interest (ROI) to quantify the mean standardized uptake value (SUVm) of 18F-fluoro-deoxy-glucose (FDG) in pulmonary lesions detected by positron emission tomography (PET). A total of 164 pairs of slices were selected in a series of PET/CT studies performed in 26 patients presenting lung tumours of various forms and complexities. On each matched CT slice, a ROI was obtained by growth-region segmentation starting from a pixel contained in the tumour. The obtained ROI was then applied to the PET image to calculate SUVm. Results were compared with the conventional manual method using a geometric ROI positioned directly on the PET lesion. The automatic delineation of the tumour from the CT image was successful in 136 sections (83%). The SUVm calculated by the manual and automatic method were respectively (mean±standard deviation) 5.05±2.39 and 6.70±3.18 ( p<0.05). The ROI size (in number of pixels) was respectively 28±23 and 21±17 ( p<0.05). The variability of the automatic method was 0% versus 20% for the manual method. SUV of FDG in PET/CT can be calculated with an excellent reproducibility by using the CT-derived limits of the lesion.

  20. 21 CFR 892.2030 - Medical image digitizer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Medical image digitizer. 892.2030 Section 892.2030...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2030 Medical image digitizer. (a) Identification. A medical image digitizer is a device intended to convert an analog medical image into a...

  1. 21 CFR 892.2030 - Medical image digitizer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical image digitizer. 892.2030 Section 892.2030...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2030 Medical image digitizer. (a) Identification. A medical image digitizer is a device intended to convert an analog medical image into a...

  2. 21 CFR 892.2030 - Medical image digitizer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Medical image digitizer. 892.2030 Section 892.2030...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2030 Medical image digitizer. (a) Identification. A medical image digitizer is a device intended to convert an analog medical image into a...

  3. 21 CFR 892.2030 - Medical image digitizer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Medical image digitizer. 892.2030 Section 892.2030...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2030 Medical image digitizer. (a) Identification. A medical image digitizer is a device intended to convert an analog medical image into a...

  4. 21 CFR 892.2030 - Medical image digitizer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Medical image digitizer. 892.2030 Section 892.2030...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2030 Medical image digitizer. (a) Identification. A medical image digitizer is a device intended to convert an analog medical image into a...

  5. PET/CT imaging in lung cancer: indications and findings*

    PubMed Central

    Hochhegger, Bruno; Alves, Giordano Rafael Tronco; Irion, Klaus Loureiro; Fritscher, Carlos Cezar; Fritscher, Leandro Genehr; Concatto, Natália Henz; Marchiori, Edson

    2015-01-01

    The use of PET/CT imaging in the work-up and management of patients with lung cancer has greatly increased in recent decades. The ability to combine functional and anatomical information has equipped PET/CT to look into various aspects of lung cancer, allowing more precise disease staging and providing useful data during the characterization of indeterminate pulmonary nodules. In addition, the accuracy of PET/CT has been shown to be greater than is that of conventional modalities in some scenarios, making PET/CT a valuable noninvasive method for the investigation of lung cancer. However, the interpretation of PET/CT findings presents numerous pitfalls and potential confounders. Therefore, it is imperative for pulmonologists and radiologists to familiarize themselves with the most relevant indications for and limitations of PET/CT, seeking to protect their patients from unnecessary radiation exposure and inappropriate treatment. This review article aimed to summarize the basic principles, indications, cancer staging considerations, and future applications related to the use of PET/CT in lung cancer. PMID:26176525

  6. Annotation-free probabilistic atlas learning for robust anatomy detection in CT images

    NASA Astrophysics Data System (ADS)

    Franz, Astrid; Schadewaldt, Nicole; Schulz, Heinrich; Vik, Torbjørn; Kausch, Lisa; Modersitzki, Jan; Wiemker, Rafael; Bystrov, Daniel

    2015-03-01

    A fully automatic method generating a whole body atlas from CT images is presented. The atlas serves as a reference space for annotations. It is based on a large collection of partially overlapping medical images and a registration scheme. The atlas itself consists of probabilistic tissue type maps and can represent anatomical variations. The registration scheme is based on an entropy-like measure of these maps and is robust with respect to field-of-view variations. In contrast to other atlas generation methods, which typically rely on a sufficiently large set of annotations on training cases, the presented method requires only the images. An iterative refinement strategy is used to automatically stitch the images to build the atlas. Affine registration of unseen CT images to the probabilistic atlas can be used to transfer reference annotations, e.g. organ models for segmentation initialization or reference bounding boxes for field-of-view selection. The robustness and generality of the method is shown using a three-fold cross-validation of the registration on a set of 316 CT images of unknown content and large anatomical variability. As an example, 17 organs are annotated in the atlas reference space and their localization in the test images is evaluated. The method yields a recall (sensitivity), specificity and precision of at least 96% and thus performs excellent in comparison to competitors.

  7. Medical staff extremity dosimetry in CT fluoroscopy: an anthropomorphic hand voxel phantom study.

    PubMed

    Figueira, C; Becker, F; Blunck, C; DiMaria, S; Baptista, M; Esteves, B; Paulo, G; Santos, J; Teles, P; Vaz, P

    2013-08-21

    This work aims to contribute to the study of the radiation dose distribution delivered to the hands of medical staff members during a general computed tomographic (CT) fluoroscopic guided procedure. In this study, both Monte Carlo simulations and measurements were performed. For free-in-air and computed tomography dose index (CTDI) body phantom measurements, a standard pencil ionization chamber (IC) 100 mm long was used. The CT scanner model was implemented using MCNPX (Monte Carlo N-Particle eXtended) and was successfully validated by comparing the simulated results with measurements. Subsequently, CT images of a hand, together with an anthropomorphic phantom, were voxelized and used with the MCNPX code for dose calculations. The hand dose distribution study was performed both by using thermo-luminescent detector measurements and Monte Carlo simulations. The validated simulation tool provides a new perspective for detailed investigations of CT-irradiation scenarios. Simulations show that there is a strong dose gradient, namely the even zones of the hand that are in precise vicinity to the x-ray beam only receive about 4% of the maximum dose delivered to adjacent areas which are directly exposed to the primary x-ray beam. Finally, the scatter contribution of the patient was also studied through MC simulations. The results show that for directly exposed parts of the hand surface, the dose is reduced by the body of the patient (due to the shielding), whereas the dose is increased by scattered radiation from the patient for parts of the skin that receive scattered radiation only. PMID:23877320

  8. Medical staff extremity dosimetry in CT fluoroscopy: an anthropomorphic hand voxel phantom study

    NASA Astrophysics Data System (ADS)

    Figueira, C.; Becker, F.; Blunck, C.; DiMaria, S.; Baptista, M.; Esteves, B.; Paulo, G.; Santos, J.; Teles, P.; Vaz, P.

    2013-08-01

    This work aims to contribute to the study of the radiation dose distribution delivered to the hands of medical staff members during a general computed tomographic (CT) fluoroscopic guided procedure. In this study, both Monte Carlo simulations and measurements were performed. For free-in-air and computed tomography dose index (CTDI) body phantom measurements, a standard pencil ionization chamber (IC) 100 mm long was used. The CT scanner model was implemented using MCNPX (Monte Carlo N-Particle eXtended) and was successfully validated by comparing the simulated results with measurements. Subsequently, CT images of a hand, together with an anthropomorphic phantom, were voxelized and used with the MCNPX code for dose calculations. The hand dose distribution study was performed both by using thermo-luminescent detector measurements and Monte Carlo simulations. The validated simulation tool provides a new perspective for detailed investigations of CT-irradiation scenarios. Simulations show that there is a strong dose gradient, namely the even zones of the hand that are in precise vicinity to the x-ray beam only receive about 4% of the maximum dose delivered to adjacent areas which are directly exposed to the primary x-ray beam. Finally, the scatter contribution of the patient was also studied through MC simulations. The results show that for directly exposed parts of the hand surface, the dose is reduced by the body of the patient (due to the shielding), whereas the dose is increased by scattered radiation from the patient for parts of the skin that receive scattered radiation only.

  9. Current perspectives in medical image perception

    PubMed Central

    Krupinski, Elizabeth A.

    2013-01-01

    Medical images constitute a core portion of the information a physician utilizes to render diagnostic and treatment decisions. At a fundamental level, this diagnostic process involves two basic processes: visually inspecting the image (visual perception) and rendering an interpretation (cognition). The likelihood of error in the interpretation of medical images is, unfortunately, not negligible. Errors do occur, and patients’ lives are impacted, underscoring our need to understand how physicians interact with the information in an image during the interpretation process. With improved understanding, we can develop ways to further improve decision making and, thus, to improve patient care. The science of medical image perception is dedicated to understanding and improving the clinical interpretation process. PMID:20601701

  10. [Study and realization of multidimensional visualization techniques for multimodality medical images].

    PubMed

    Li, Zhenwei; Zhang, Jianguo; Yang, Xiaoli

    2013-03-01

    This paper designed a multimodal medical image visualization system using open source VTK on platform VS2008. The system can visualize CT, MR, PET and SPECT using different visualization methods, such as multi-planar reconstruction (MPR), curved planar reformation (CPR), direct volume rendering (DVR), indirect volume rendering (IVR) and maximum intensity projection (MIP). Clinical practice shows that the system has stable performance and the visualization methods which make the reading of different modal medical images more convenient. The maximum number of CT slices the system can reconstruct is more than 2 000, and the reconstruction speed and quality meet the clinical requirements. PMID:23777062

  11. Anniversary paper: evaluation of medical imaging systems.

    PubMed

    Krupinski, Elizabeth A; Jiang, Yulei

    2008-02-01

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

  12. Multimodality Imaging in Pediatric Osteosarcoma in the Era of Image Gently and Image Wisely Campaign With a Close Look at the CT Scan Radiation Dose.

    PubMed

    Vijayakumar, Vani; Collier, Anderson B; Ruan, Chun; Zhang, Xu; Lowery, Rachel; Barr, Jennifer; Hicks, Chindo; Megason, Gail; Vijayakumar, Srinivasan

    2016-04-01

    The increasing use of serial multimodality imaging in the management of pediatric osteosarcoma raises concern of over exposure to ionizing radiation in children, especially from repeated computed tomographic (CT) scans. This study reviews the utilization of multimodality imaging in patients with osteosarcoma at our institution and analyzes any potential radiation-related complications. Twenty-eight patients were identified. Three patients developed late complications-acute myeloid leukemia, myelodysplastic syndrome, and early menopause. Using the patient's age and body part imaged, CT dose length product and effective dose was estimated with the use of a conversion factor for 19 patients. The effective doses were higher in the 3 patients with late complications than the other patients in the cohort (P=0.018). These results suggest an increased risk for adverse effects with higher CT exposures and effective doses. On the basis of our data and published data, methods to decrease the doses of radiation from medical imaging need to be explored. The number of CT scans may be limited. Implementing the Image Gently concept to decrease radiation exposure can be beneficial in modification of CT acquisition parameters. PMID:26583624

  13. Gastric Cancer Staging with Dual Energy Spectral CT Imaging

    PubMed Central

    Pan, Zilai; Pang, Lifang; Ding, Bei; Yan, Chao; Zhang, Huan; Du, Lianjun; Wang, Baisong; Song, Qi; Chen, Kemin; Yan, Fuhua

    2013-01-01

    Purpose To evaluate the clinical utility of dual energy spectral CT (DEsCT) in staging and characterizing gastric cancers. Materials and Methods 96 patients suspected of gastric cancers underwent dual-phasic scans (arterial phase (AP) and portal venous phase (PP)) with DEsCT mode. Three types of images were reconstructed for analysis: conventional polychromatic images, material-decomposition images, and monochromatic image sets with photon energies from 40 to 140 keV. The polychromatic and monochromatic images were compared in TNM staging. The iodine concentrations in the lesions and lymph nodes were measured on the iodine-based material-decomposition images. These values were further normalized against that in aorta and the normalized iodine concentration (nIC) values were statistically compared. Results were correlated with pathological findings. Results The overall accuracies for T, N and M staging were (81.2%, 80.0%, and 98.9%) and (73.9%, 75.0%, and 98.9%) determined with the monochromatic images and the conventional kVp images, respectively. The improvement of the accuracy in N-staging using the keV images was statistically significant (p<0.05). The nIC values between the differentiated and undifferentiated carcinoma and between metastatic and non-metastatic lymph nodes were significantly different both in AP (p = 0.02, respectively) and PP (p = 0.01, respectively). Among metastatic lymph nodes, nIC of the signet-ring cell carcinoma were significantly different from the adenocarcinoma (p = 0.02) and mucinous adenocarcinoma (p = 0.01) in PP. Conclusion The monochromatic images obtained with DEsCT may be used to improve the N-staging accuracy. Quantitative iodine concentration measurements may be helpful for differentiating between differentiated and undifferentiated gastric carcinoma, and between metastatic and non-metastatic lymph nodes. PMID:23424614

  14. Automated planning of breast radiotherapy using cone beam CT imaging

    SciTech Connect

    Amit, Guy; Purdie, Thomas G.

    2015-02-15

    Purpose: Develop and clinically validate a methodology for using cone beam computed tomography (CBCT) imaging in an automated treatment planning framework for breast IMRT. Methods: A technique for intensity correction of CBCT images was developed and evaluated. The technique is based on histogram matching of CBCT image sets, using information from “similar” planning CT image sets from a database of paired CBCT and CT image sets (n = 38). Automated treatment plans were generated for a testing subset (n = 15) on the planning CT and the corrected CBCT. The plans generated on the corrected CBCT were compared to the CT-based plans in terms of beam parameters, dosimetric indices, and dose distributions. Results: The corrected CBCT images showed considerable similarity to their corresponding planning CTs (average mutual information 1.0±0.1, average sum of absolute differences 185 ± 38). The automated CBCT-based plans were clinically acceptable, as well as equivalent to the CT-based plans with average gantry angle difference of 0.99°±1.1°, target volume overlap index (Dice) of 0.89±0.04 although with slightly higher maximum target doses (4482±90 vs 4560±84, P < 0.05). Gamma index analysis (3%, 3 mm) showed that the CBCT-based plans had the same dose distribution as plans calculated with the same beams on the registered planning CTs (average gamma index 0.12±0.04, gamma <1 in 99.4%±0.3%). Conclusions: The proposed method demonstrates the potential for a clinically feasible and efficient online adaptive breast IMRT planning method based on CBCT imaging, integrating automation.

  15. Phantom validation of coregistration of PET and CT for image-guided radiotherapy.

    PubMed

    Lavely, William C; Scarfone, Christopher; Cevikalp, Hakan; Li, Rui; Byrne, Daniel W; Cmelak, Anthony J; Dawant, Benoit; Price, Ronald R; Hallahan, Dennis E; Fitzpatrick, J Michael

    2004-05-01

    Radiotherapy treatment planning integrating positron emission tomography (PET) and computerized tomography (CT) is rapidly gaining acceptance in the clinical setting. Although hybrid systems are available, often the planning CT is acquired on a dedicated system separate from the PET scanner. A limiting factor to using PET data becomes the accuracy of the CT/PET registration. In this work, we use phantom and patient validation to demonstrate a general method for assessing the accuracy of CT/PET image registration and apply it to two multi-modality image registration programs. An IAEA (International Atomic Energy Association) brain phantom and an anthropomorphic head phantom were used. Internal volumes and externally mounted fiducial markers were filled with CT contrast and 18F-fluorodeoxyglucose (FDG). CT, PET emission, and PET transmission images were acquired and registered using two different image registration algorithms. CT/PET Fusion (GE Medical Systems, Milwaukee, WI) is commercially available and uses a semi-automated initial step followed by manual adjustment. Automatic Mutual Information-based Registration (AMIR), developed at our institution, is fully automated and exhibits no variation between repeated registrations. Registration was performed using distinct phantom structures; assessment of accuracy was determined from registration of the calculated centroids of a set of fiducial markers. By comparing structure-based registration with fiducial-based registration, target registration error (TRE) was computed at each point in a three-dimensional (3D) grid that spans the image volume. Identical methods were also applied to patient data to assess CT/PET registration accuracy. Accuracy was calculated as the mean with standard deviation of the TRE for every point in the 3D grid. Overall TRE values for the IAEA brain phantom are: CT/PET Fusion = 1.71 +/- 0.62 mm, AMIR = 1.13 +/- 0.53 mm; overall TRE values for the anthropomorphic head phantom are: CT

  16. Facilitating medical information search using Google Glass connected to a content-based medical image retrieval system.

    PubMed

    Widmer, Antoine; Schaer, Roger; Markonis, Dimitrios; Muller, Henning

    2014-01-01

    Wearable computing devices are starting to change the way users interact with computers and the Internet. Among them, Google Glass includes a small screen located in front of the right eye, a camera filming in front of the user and a small computing unit. Google Glass has the advantage to provide online services while allowing the user to perform tasks with his/her hands. These augmented glasses uncover many useful applications, also in the medical domain. For example, Google Glass can easily provide video conference between medical doctors to discuss a live case. Using these glasses can also facilitate medical information search by allowing the access of a large amount of annotated medical cases during a consultation in a non-disruptive fashion for medical staff. In this paper, we developed a Google Glass application able to take a photo and send it to a medical image retrieval system along with keywords in order to retrieve similar cases. As a preliminary assessment of the usability of the application, we tested the application under three conditions (images of the skin; printed CT scans and MRI images; and CT and MRI images acquired directly from an LCD screen) to explore whether using Google Glass affects the accuracy of the results returned by the medical image retrieval system. The preliminary results show that despite minor problems due to the relative stability of the Google Glass, images can be sent to and processed by the medical image retrieval system and similar images are returned to the user, potentially helping in the decision making process. PMID:25570993

  17. Automatic segmentation of vertebral contours from CT images using fuzzy corners.

    PubMed

    Athertya, Jiyo S; Saravana Kumar, G

    2016-05-01

    Automatic segmentation of bone in computed tomography (CT) images is critical for the implementation of computer-assisted diagnosis which has increasing potential in the evaluation of various spine disorders. Of the many techniques available for delineating the region of interest (ROI), active contour methods (ACM) are well-established techniques that are used to segment medical images. The initialization for these methods is either through manual intervention or by applying a global threshold, thus making them semi-automatic in nature. The paper presents a methodology for automatic contour initialization in ACM and demonstrates the applicability of the method for medical image segmentation from spinal CT images. Initially, a set of feature markers from the image is extracted to construct an initial contour for the ACM. A fuzzified corner metric, based on image intensity, is proposed to identify the feature markers to be enclosed by the contour. A concave hull based on α shape, is constructed using these fuzzy corners to give the initial contour. The proposed method was evaluated against conventional feature detectors and other initialization methods. The results show the method׳s robust performance in the presence of simulated Gaussian noise levels. The method enables the ACM to efficiently converge to the ground truth segmentation. The reference standard for comparison was the annotated images from a radiologist, and the Dice coefficient and Hausdorff distance measures were used to evaluate the segmentation. PMID:27017068

  18. Optical crosstalk in CT detectors and its effects on CT images

    NASA Astrophysics Data System (ADS)

    Youn, Hanbean; Kam, Soohwa; Han, Jong Chul; Kim, Ho Kyung

    2014-03-01

    Detectors for computed tomography (CT) typically consist of scintillator and photodiode arrays which are coupled using optical glue. Therefore, the leakage of optical photons generated in a scintillator block to neighboring pixel photodiodes through the optical glue layer is inevitable. Passivation layers to protect the silicon photodiode as well as the silicon layer itself, which is inactive to the optical photons, are another causes for the leakage. This optical crosstalk reduces image sharpness, and eventually will blur CT images. We have quantitatively investigated the optical crosstalk in CT detectors using the Monte Carlo technique. We performed the optical Monte Carlo simulations for various thicknesses of optical components in a 129 × 129 CT detector array. We obtained the coordinates of optical photons hitting the user-defined detection plane. From the coordinate information, we calculated the collection efficiency at the detection plane and the collection efficiency at the single pixel located just below the scintillator in which the optical photons were generated. Difference between the two quantities provided the optical crosstalk. In addition, using the coordinate information, we calculated point-spread functions as well as modulation-transfer functions from which we estimated the effective aperture due to the optical photon spreading. The optical crosstalk was most severely affected by the thickness of photodiode passivation layer. The effective aperture due to the optical crosstalk was about 110% of the detector pixel aperture for a 0.1 mm-thick passivation layer, and this signal blur was appeared as a relative error of about 3-4% in mismatches between CT images with and without the optical crosstalk. The detailed simulation results are shown and will be very useful for the design of CT detectors.

  19. Recent Advances in Cardiac Computed Tomography: Dual Energy, Spectral and Molecular CT Imaging

    PubMed Central

    Danad, Ibrahim; Fayad, Zahi A.; Willemink, Martin J.; Min, James K.

    2015-01-01

    Computed tomography (CT) evolved into a powerful diagnostic tool and it is impossible to imagine current clinical practice without CT imaging. Due to its widespread availability, ease of clinical application, superb sensitivity for detection of CAD, and non-invasive nature, CT has become a valuable tool within the armamentarium of the cardiologist. In the last few years, numerous technological advances in CT have occurred—including dual energy CT (DECT), spectral CT and CT-based molecular imaging. By harnessing the advances in technology, cardiac CT has advanced beyond the mere evaluation of coronary stenosis to an imaging modality tool that permits accurate plaque characterization, assessment of myocardial perfusion and even probing of molecular processes that are involved in coronary atherosclerosis. Novel innovations in CT contrast agents and pre-clinical spectral CT devices have paved the way for CT-based molecular imaging. PMID:26068288

  20. New Applications of Cardiac Computed Tomography: Dual-Energy, Spectral, and Molecular CT Imaging.

    PubMed

    Danad, Ibrahim; Fayad, Zahi A; Willemink, Martin J; Min, James K

    2015-06-01

    Computed tomography (CT) has evolved into a powerful diagnostic tool, and it is impossible to imagine current clinical practice without CT imaging. Because of its widespread availability, ease of clinical application, superb sensitivity for the detection of coronary artery disease, and noninvasive nature, CT has become a valuable tool within the armamentarium of cardiologists. In the past few years, numerous technological advances in CT have occurred, including dual-energy CT, spectral CT, and CT-based molecular imaging. By harnessing the advances in technology, cardiac CT has advanced beyond the mere evaluation of coronary stenosis to an imaging tool that permits accurate plaque characterization, assessment of myocardial perfusion, and even probing of molecular processes that are involved in coronary atherosclerosis. Novel innovations in CT contrast agents and pre-clinical spectral CT devices have paved the way for CT-based molecular imaging. PMID:26068288

  1. Multispectral imaging for medical diagnosis

    NASA Technical Reports Server (NTRS)

    Anselmo, V. J.

    1977-01-01

    Photography technique determines amount of morbidity present in tissue. Imaging apparatus incorporates numerical filtering. Overall system operates in near-real time. Information gained from this system enables physician to understand extent of injury and leads to accelerated treatment.

  2. Dental imaging using laminar optical tomography and micro CT

    NASA Astrophysics Data System (ADS)

    Long, Feixiao; Ozturk, Mehmet S.; Intes, Xavier; Kotha, Shiva

    2014-02-01

    Dental lesions located in the pulp are quite difficult to identify based on anatomical contrast, and, hence, to diagnose using traditional imaging methods such as dental CT. However, such lesions could lead to functional and/or molecular optical contrast. Herein, we report on the preliminary investigation of using Laminar Optical Tomography (LOT) to image the pulp and root canals in teeth. LOT is a non-contact, high resolution, molecular and functional mesoscopic optical imaging modality. To investigate the potential of LOT for dental imaging, we injected an optical dye into ex vivo teeth samples and imaged them using LOT and micro-CT simultaneously. A rigid image registration between the LOT and micro-CT reconstruction was obtained, validating the potential of LOT to image molecular optical contrast deep in the teeth with accuracy, non-invasively. We demonstrate that LOT can retrieve the 3D bio-distribution of molecular probes at depths up to 2mm with a resolution of several hundred microns in teeth.

  3. Why do commercial CT scanners still employ traditional, filtered back-projection for image reconstruction?

    PubMed Central

    Pan, Xiaochuan; Sidky, Emil Y; Vannier, Michael

    2010-01-01

    Despite major advances in x-ray sources, detector arrays, gantry mechanical design and especially computer performance, one component of computed tomography (CT) scanners has remained virtually constant for the past 25 years—the reconstruction algorithm. Fundamental advances have been made in the solution of inverse problems, especially tomographic reconstruction, but these works have not been translated into clinical and related practice. The reasons are not obvious and seldom discussed. This review seeks to examine the reasons for this discrepancy and provides recommendations on how it can be resolved. We take the example of field of compressive sensing (CS), summarizing this new area of research from the eyes of practical medical physicists and explaining the disconnection between theoretical and application-oriented research. Using a few issues specific to CT, which engineers have addressed in very specific ways, we try to distill the mathematical problem underlying each of these issues with the hope of demonstrating that there are interesting mathematical problems of general importance that can result from in depth analysis of specific issues. We then sketch some unconventional CT-imaging designs that have the potential to impact on CT applications, if the link between applied mathematicians and engineers/physicists were stronger. Finally, we close with some observations on how the link could be strengthened. There is, we believe, an important opportunity to rapidly improve the performance of CT and related tomographic imaging techniques by addressing these issues. PMID:20376330

  4. Multi-channel medical imaging system

    DOEpatents

    Frangioni, John V.

    2016-05-03

    A medical imaging system provides simultaneous rendering of visible light and fluorescent images. The system may employ dyes in a small-molecule form that remain in a subject's blood stream for several minutes, allowing real-time imaging of the subject's circulatory system superimposed upon a conventional, visible light image of the subject. The system may provide an excitation light source to excite the fluorescent substance and a visible light source for general illumination within the same optical guide used to capture images. The system may be configured for use in open surgical procedures by providing an operating area that is closed to ambient light. The systems described herein provide two or more diagnostic imaging channels for capture of multiple, concurrent diagnostic images and may be used where a visible light image may be usefully supplemented by two or more images that are independently marked for functional interest.

  5. Multi-channel medical imaging system

    DOEpatents

    Frangioni, John V

    2013-12-31

    A medical imaging system provides simultaneous rendering of visible light and fluorescent images. The system may employ dyes in a small-molecule form that remain in the subject's blood stream for several minutes, allowing real-time imaging of the subject's circulatory system superimposed upon a conventional, visible light image of the subject. The system may provide an excitation light source to excite the fluorescent substance and a visible light source for general illumination within the same optical guide used to capture images. The system may be configured for use in open surgical procedures by providing an operating area that is closed to ambient light. The systems described herein provide two or more diagnostic imaging channels for capture of multiple, concurrent diagnostic images and may be used where a visible light image may be usefully supplemented by two or more images that are independently marked for functional interest.

  6. Acoustic Waves in Medical Imaging and Diagnostics

    PubMed Central

    Sarvazyan, Armen P.; Urban, Matthew W.; Greenleaf, James F.

    2013-01-01

    Up until about two decades ago acoustic imaging and ultrasound imaging were synonymous. The term “ultrasonography,” or its abbreviated version “sonography” meant an imaging modality based on the use of ultrasonic compressional bulk waves. Since the 1990s numerous acoustic imaging modalities started to emerge based on the use of a different mode of acoustic wave: shear waves. It was demonstrated that imaging with these waves can provide very useful and very different information about the biological tissue being examined. We will discuss physical basis for the differences between these two basic modes of acoustic waves used in medical imaging and analyze the advantages associated with shear acoustic imaging. A comprehensive analysis of the range of acoustic wavelengths, velocities, and frequencies that have been used in different imaging applications will be presented. We will discuss the potential for future shear wave imaging applications. PMID:23643056

  7. Edge detection in medical images using a genetic algorithm.

    PubMed

    Gudmundsson, M; El-Kwae, E A; Kabuka, M R

    1998-06-01

    An algorithm is developed that detects well-localized, unfragmented, thin edges in medical images based on optimization of edge configurations using a genetic algorithm (GA). Several enhancements were added to improve the performance of the algorithm over a traditional GA. The edge map is split into connected subregions to reduce the solution space and simplify the problem. The edge-map is then optimized in parallel using incorporated genetic operators that perform transforms on edge structures. Adaptation is used to control operator probabilities based on their participation. The GA was compared to the simulated annealing (SA) approach using ideal and actual medical images from different modalities including magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound. Quantitative comparisons were provided based on the Pratt figure of merit and on the cost-function minimization. The detected edges were thin, continuous, and well localized. Most of the basic edge features were detected. Results for different medical image modalities are promising and encourage further investigation to improve the accuracy and experiment with different cost functions and genetic operators. PMID:9735910

  8. Medical image segmentation using genetic algorithms.

    PubMed

    Maulik, Ujjwal

    2009-03-01

    Genetic algorithms (GAs) have been found to be effective in the domain of medical image segmentation, since the problem can often be mapped to one of search in a complex and multimodal landscape. The challenges in medical image segmentation arise due to poor image contrast and artifacts that result in missing or diffuse organ/tissue boundaries. The resulting search space is therefore often noisy with a multitude of local optima. Not only does the genetic algorithmic framework prove to be effective in coming out of local optima, it also brings considerable flexibility into the segmentation procedure. In this paper, an attempt has been made to review the major applications of GAs to the domain of medical image segmentation. PMID:19272859

  9. Osmotic blood-brain barrier disruption: CT and radionuclide imaging

    SciTech Connect

    Roman-Goldstein, S.; Clunie, D.A.; Stevens, J.; Hogan, R.; Monard, J.; Ramsey, F.; Neuwelt, E.A.

    1994-03-01

    The purpose of this study was to compare CT and radionuclide imaging of osmotic blood-brain barrier disruption, and to develop a quantitative method for imaging osmotic blood-brain barrier disruption and to see if iopamidol could be safety given intravenously in conjunction with blood-brain barrier disruption. Forty-five blood-brain barrier disruption procedures were imaged with CT and radionuclide scans. The scans were evaluated with visual and quantitative scales. Patients were observed for adverse effects after blood-brain barrier disruption. There was a 4% rate of seizures in this study. There was good agreement between visual CT and radionuclide grading systems. Quantitative disruption did not add useful information to visual interpretations. Nonionic iodine-based contrast medium has a lower incidence of seizures when injected intravenously in conjunction with osmotic blood-brain barrier disruption than ionic contrast material. Contrast-enhanced CT is the preferred method to image disruption because it has better spatial resolution than radionuclide techniques. 34 refs., 4 figs., 6 tabs.

  10. Computer aided detection of oral lesions on CT images

    NASA Astrophysics Data System (ADS)

    Galib, S.; Islam, F.; Abir, M.; Lee, H. K.

    2015-12-01

    Oral lesions are important findings on computed tomography (CT) images. In this study, a fully automatic method to detect oral lesions in mandibular region from dental CT images is proposed. Two methods were developed to recognize two types of lesions namely (1) Close border (CB) lesions and (2) Open border (OB) lesions, which cover most of the lesion types that can be found on CT images. For the detection of CB lesions, fifteen features were extracted from each initial lesion candidates and multi layer perceptron (MLP) neural network was used to classify suspicious regions. Moreover, OB lesions were detected using a rule based image processing method, where no feature extraction or classification algorithm were used. The results were validated using a CT dataset of 52 patients, where 22 patients had abnormalities and 30 patients were normal. Using non-training dataset, CB detection algorithm yielded 71% sensitivity with 0.31 false positives per patient. Furthermore, OB detection algorithm achieved 100% sensitivity with 0.13 false positives per patient. Results suggest that, the proposed framework, which consists of two methods, has the potential to be used in clinical context, and assist radiologists for better diagnosis.

  11. Justification of CT scans using referral guidelines for imaging.

    PubMed

    Stanescu, G; Rosca-Fartat, G; Stanescu, D

    2015-07-01

    This study analyses the efficiency of the justification of individual computed tomography (CT) procedures using the good practice guide. The conformity of the CT scans with guide's recommendations was retrospectively analysed in a paediatric emergency hospital in Romania. The involved patient doses were estimated. The results show that around one-third of the examinations were not prescribed in conformity with the guide's recommendations, but these results are affected by unclear guide provisions, discussed here. The implications of the provisions of the revised International Atomic Energy Agency's Basic Safety Standards and of the Council Directive 2013/59/EURATOM were analysed. The education and training courses for medical doctors disseminating the provisions of the good practice guide should be considered as the main support for the justification of the CT scans at the individual level. PMID:25805882

  12. DICOM: a standard for medical imaging

    NASA Astrophysics Data System (ADS)

    Horii, Steven C.; Bidgood, W. Dean

    1993-01-01

    Since 1983, the American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA) have been engaged in developing standards related to medical imaging. This alliance of users and manufacturers was formed to meet the needs of the medical imaging community as its use of digital imaging technology increased. The development of electronic picture archiving and communications systems (PACS), which could connect a number of medical imaging devices together in a network, led to the need for a standard interface and data structure for use on imaging equipment. Since medical image files tend to be very large and include much text information along with the image, the need for a fast, flexible, and extensible standard was quickly established. The ACR-NEMA Digital Imaging and Communications Standards Committee developed a standard which met these needs. The standard (ACR-NEMA 300-1988) was first published in 1985 and revised in 1988. It is increasingly available from equipment manufacturers. The current work of the ACR- NEMA Committee has been to extend the standard to incorporate direct network connection features, and build on standards work done by the International Standards Organization in its Open Systems Interconnection series. This new standard, called Digital Imaging and Communication in Medicine (DICOM), follows an object-oriented design methodology and makes use of as many existing internationally accepted standards as possible. This paper gives a brief overview of the requirements for communications standards in medical imaging, a history of the ACR-NEMA effort and what it has produced, and a description of the DICOM standard.

  13. Medical Image Retrieval: Past and Present

    PubMed Central

    Hwang, Kyung Hoon; Lee, Haejun

    2012-01-01

    With the widespread dissemination of picture archiving and communication systems (PACSs) in hospitals, the amount of imaging data is rapidly increasing. Effective image retrieval systems are required to manage these complex and large image databases. The authors reviewed the past development and the present state of medical image retrieval systems including text-based and content-based systems. In order to provide a more effective image retrieval service, the intelligent content-based retrieval systems combined with semantic systems are required. PMID:22509468

  14. Accuracy of CT-based attenuation correction in PET/CT bone imaging

    NASA Astrophysics Data System (ADS)

    Abella, Monica; Alessio, Adam M.; Mankoff, David A.; MacDonald, Lawrence R.; Vaquero, Juan Jose; Desco, Manuel; Kinahan, Paul E.

    2012-05-01

    We evaluate the accuracy of scaling CT images for attenuation correction of PET data measured for bone. While the standard tri-linear approach has been well tested for soft tissues, the impact of CT-based attenuation correction on the accuracy of tracer uptake in bone has not been reported in detail. We measured the accuracy of attenuation coefficients of bovine femur segments and patient data using a tri-linear method applied to CT images obtained at different kVp settings. Attenuation values at 511 keV obtained with a 68Ga/68Ge transmission scan were used as a reference standard. The impact of inaccurate attenuation images on PET standardized uptake values (SUVs) was then evaluated using simulated emission images and emission images from five patients with elevated levels of FDG uptake in bone at disease sites. The CT-based linear attenuation images of the bovine femur segments underestimated the true values by 2.9 ± 0.3% for cancellous bone regardless of kVp. For compact bone the underestimation ranged from 1.3% at 140 kVp to 14.1% at 80 kVp. In the patient scans at 140 kVp the underestimation was approximately 2% averaged over all bony regions. The sensitivity analysis indicated that errors in PET SUVs in bone are approximately proportional to errors in the estimated attenuation coefficients for the same regions. The variability in SUV bias also increased approximately linearly with the error in linear attenuation coefficients. These results suggest that bias in bone uptake SUVs of PET tracers ranges from 2.4% to 5.9% when using CT scans at 140 and 120 kVp for attenuation correction. Lower kVp scans have the potential for considerably more error in dense bone. This bias is present in any PET tracer with bone uptake but may be clinically insignificant for many imaging tasks. However, errors from CT-based attenuation correction methods should be carefully evaluated if quantitation of tracer uptake in bone is important.

  15. Phase and amplitude binning for 4D-CT imaging.

    PubMed

    Abdelnour, A F; Nehmeh, S A; Pan, T; Humm, J L; Vernon, P; Schöder, H; Rosenzweig, K E; Mageras, G S; Yorke, E; Larson, S M; Erdi, Y E

    2007-06-21

    We compare the consistency and accuracy of two image binning approaches used in 4D-CT imaging. One approach, phase binning (PB), assigns each breathing cycle 2pi rad, within which the images are grouped. In amplitude binning (AB), the images are assigned bins according to the breathing signal's full amplitude. To quantitate both approaches we used a NEMA NU2-2001 IEC phantom oscillating in the axial direction and at random frequencies and amplitudes, approximately simulating a patient's breathing. 4D-CT images were obtained using a four-slice GE Lightspeed CT scanner operating in cine mode. We define consistency error as a measure of ability to correctly bin over repeated cycles in the same field of view. Average consistency error mue+/-sigmae in PB ranged from 18%+/-20% to 30%+/-35%, while in AB the error ranged from 11%+/-14% to 20%+/-24%. In PB nearly all bins contained sphere slices. AB was more accurate, revealing empty bins where no sphere slices existed. As a proof of principle, we present examples of two non-small cell lung carcinoma patients' 4D-CT lung images binned by both approaches. While AB can lead to gaps in the coronal images, depending on the patient's breathing pattern, PB exhibits no gaps but suffers visible artifacts due to misbinning, yielding images that cover a relatively large amplitude range. AB was more consistent, though often resulted in gaps when no data existed due to patients' breathing pattern. We conclude AB is more accurate than PB. This has important consequences to treatment planning and diagnosis. PMID:17664557

  16. CT scan of the brain (image)

    MedlinePlus

    ... allowing high definition not only of the bony structures, but of the soft tissues. Clear images of organs such as the brain, muscles, joint structures, veins and arteries, as well as anomalies like ...

  17. Use of mobile devices for medical imaging.

    PubMed

    Hirschorn, David S; Choudhri, Asim F; Shih, George; Kim, Woojin

    2014-12-01

    Mobile devices have fundamentally changed personal computing, with many people forgoing the desktop and even laptop computer altogether in favor of a smaller, lighter, and cheaper device with a touch screen. Doctors and patients are beginning to expect medical images to be available on these devices for consultative viewing, if not actual diagnosis. However, this raises serious concerns with regard to the ability of existing mobile devices and networks to quickly and securely move these images. Medical images often come in large sets, which can bog down a network if not conveyed in an intelligent manner, and downloaded data on a mobile device are highly vulnerable to a breach of patient confidentiality should that device become lost or stolen. Some degree of regulation is needed to ensure that the software used to view these images allows all relevant medical information to be visible and manipulated in a clinically acceptable manner. There also needs to be a quality control mechanism to ensure that a device's display accurately conveys the image content without loss of contrast detail. Furthermore, not all mobile displays are appropriate for all types of images. The smaller displays of smart phones, for example, are not well suited for viewing entire chest radiographs, no matter how small and numerous the pixels of the display may be. All of these factors should be taken into account when deciding where, when, and how to use mobile devices for the display of medical images. PMID:25467905

  18. Medical Applications of Microwave Imaging

    PubMed Central

    Wang, Zhao; Lim, Eng Gee; Tang, Yujun

    2014-01-01

    Ultrawide band (UWB) microwave imaging is a promising method for the detection of early stage breast cancer, based on the large contrast in electrical parameters between malignant tumour tissue and the surrounding normal breast-tissue. In this paper, the detection and imaging of a malignant tumour are performed through a tomographic based microwave system and signal processing. Simulations of the proposed system are performed and postimage processing is presented. Signal processing involves the extraction of tumour information from background information and then image reconstruction through the confocal method delay-and-sum algorithms. Ultimately, the revision of time-delay and the superposition of more tumour signals are applied to improve accuracy. PMID:25379515

  19. A lossless encryption method for medical images using edge maps.

    PubMed

    Zhou, Yicong; Panetta, Karen; Agaian, Sos

    2009-01-01

    Image encryption is an effective approach for providing security and privacy protection for medical images. This paper introduces a new lossless approach, called EdgeCrypt, to encrypt medical images using the information contained within an edge map. The algorithm can fully protect the selected objects/regions within medical images or the entire medical images. It can also encrypt other types of images such as grayscale images or color images. The algorithm can be used for privacy protection in the real-time medical applications such as wireless medical networking and mobile medical services. PMID:19965008

  20. Gamma Knife radiosurgery with CT image-based dose calculation.

    PubMed

    Xu, Andy Yuanguang; Bhatnagar, Jagdish; Bednarz, Greg; Niranjan, Ajay; Kondziolka, Douglas; Flickinger, John; Lunsford, L Dade; Huq, M Saiful

    2015-01-01

    The Leksell GammaPlan software version 10 introduces a CT image-based segmentation tool for automatic skull definition and a convolution dose calculation algorithm for tissue inhomogeneity correction. The purpose of this work was to evaluate the impact of these new approaches on routine clinical Gamma Knife treatment planning. Sixty-five patients who underwent CT image-guided Gamma Knife radiosurgeries at the University of Pittsburgh Medical Center in recent years were retrospectively investigated. The diagnoses for these cases include trigeminal neuralgia, meningioma, acoustic neuroma, AVM, glioma, and benign and metastatic brain tumors. Dose calculations were performed for each patient with the same dose prescriptions and the same shot arrangements using three different approaches: 1) TMR 10 dose calculation with imaging skull definition; 2) convolution dose calculation with imaging skull definition; 3) TMR 10 dose calculation with conventional measurement-based skull definition. For each treatment matrix, the total treatment time, the target coverage index, the selectivity index, the gradient index, and a set of dose statistics parameters were compared between the three calculations. The dose statistics parameters investigated include the prescription isodose volume, the 12 Gy isodose volume, the minimum, maximum and mean doses on the treatment targets, and the critical structures under consideration. The difference between the convolution and the TMR 10 dose calculations for the 104 treatment matrices were found to vary with the patient anatomy, location of the treatment shots, and the tissue inhomogeneities around the treatment target. An average difference of 8.4% was observed for the total treatment times between the convolution and the TMR algorithms. The maximum differences in the treatment times, the prescription isodose volumes, the 12 Gy isodose volumes, the target coverage indices, the selectivity indices, and the gradient indices from the convolution

  1. Imaging lobular breast carcinoma: comparison of synchrotron radiation DEI-CT technique with clinical CT, mammography and histology

    NASA Astrophysics Data System (ADS)

    Fiedler, S.; Bravin, A.; Keyriläinen, J.; Fernández, M.; Suortti, P.; Thomlinson, W.; Tenhunen, M.; Virkkunen, P.; Karjalainen-Lindsberg, M.-L.

    2004-01-01

    Different modalities for imaging cancer-bearing breast tissue samples are described and compared. The images include clinical mammograms and computed tomography (CT) images, CT images with partly coherent synchrotron radiation (SR), and CT and radiography images taken with SR using the diffraction enhanced imaging (DEI) method. The images are evaluated by a radiologist and compared with histopathological examination of the samples. Two cases of lobular carcinoma are studied in detail. The indications of cancer are very weak or invisible in the conventional images, but the morphological changes due to invasion of cancer become pronounced in the images taken by the DEI method. The strands penetrating adipose tissue are seen clearly in the DEI-CT images, and the histopathology confirms that some strands contain the so-called 'Indian file' formations of cancer cells. The radiation dose is carefully measured for each of the imaging modalities. The mean glandular dose (MGD) for 50% glandular breast tissue is about 1 mGy in conventional mammography and less than 0.25 mGy in projection DEI, while in the clinical CT imaging the MGD is very high, about 45 mGy. The entrance dose of 95 mGy in DEI-CT imaging gives rise to an MGD of 40 mGy, but the dose may be reduced by an order of magnitude, because the contrast is very large in most images.

  2. Computer-aided kidney segmentation on abdominal CT images.

    PubMed

    Lin, Daw-Tung; Lei, Chung-Chih; Hung, Siu-Wan

    2006-01-01

    In this paper, an effective model-based approach for computer-aided kidney segmentation of abdominal CT images with anatomic structure consideration is presented. This automatic segmentation system is expected to assist physicians in both clinical diagnosis and educational training. The proposed method is a coarse to fine segmentation approach divided into two stages. First, the candidate kidney region is extracted according to the statistical geometric location of kidney within the abdomen. This approach is applicable to images of different sizes by using the relative distance of the kidney region to the spine. The second stage identifies the kidney by a series of image processing operations. The main elements of the proposed system are: 1) the location of the spine is used as the landmark for coordinate references; 2) elliptic candidate kidney region extraction with progressive positioning on the consecutive CT images; 3) novel directional model for a more reliable kidney region seed point identification; and 4) adaptive region growing controlled by the properties of image homogeneity. In addition, in order to provide different views for the physicians, we have implemented a visualization tool that will automatically show the renal contour through the method of second-order neighborhood edge detection. We considered segmentation of kidney regions from CT scans that contain pathologies in clinical practice. The results of a series of tests on 358 images from 30 patients indicate an average correlation coefficient of up to 88% between automatic and manual segmentation. PMID:16445250

  3. Theoretical analysis of x-ray CT phase-contrast imaging

    NASA Astrophysics Data System (ADS)

    Feng, Sheng; Liu, Song; Zhang, Xuelong

    2008-12-01

    Recently phase contrast imaging has attracted much attention. An obvious advantage of using X-rays for imaging the internal structure of relatively thick samples lies in its high degree of penetration of solid objects. However, often leads to poor image contrast for soft tissue. Phase contrast imaging can be very useful in such situation, as the phase of the transmitted beam may often be more sensitive indicator of density of sample than convention contrast. On the other hand, Computed Tomography is the best technology in the aspect of X-rays detection. Using the technology, the detected object can be imaged to three-dimensional image, so as to observe the inner structure of object, and be convenient to the disease examination. If the phase contrast imaging can be used to the technology of Computed Tomography, the high resolution image can be gained. The technology will become the development orientation of medical image. The aim of this article was to apply the theory of X-rays phase contrast imaging to the traditional X-CT technique. For this purpose, the formula deduced from the imaging theory with parallel monochromatic X-rays illuminating the object based on the Fresnel-Kircohhof theory had been completed and a formula similar to that of the traditional X-CT reconstruction had been gained, which was Radon transform formula. At last, X-rays reconstruction simulation had been carried out according to the formula, and proved that the method could be used in clinical medical imaging. The method discussed in this paper had a very bright prospect for application.

  4. An open architecture for medical image workstation

    NASA Astrophysics Data System (ADS)

    Liang, Liang; Hu, Zhiqiang; Wang, Xiangyun

    2005-04-01

    Dealing with the difficulties of integrating various medical image viewing and processing technologies with a variety of clinical and departmental information systems and, in the meantime, overcoming the performance constraints in transferring and processing large-scale and ever-increasing image data in healthcare enterprise, we design and implement a flexible, usable and high-performance architecture for medical image workstations. This architecture is not developed for radiology only, but for any workstations in any application environments that may need medical image retrieving, viewing, and post-processing. This architecture contains an infrastructure named Memory PACS and different kinds of image applications built on it. The Memory PACS is in charge of image data caching, pre-fetching and management. It provides image applications with a high speed image data access and a very reliable DICOM network I/O. In dealing with the image applications, we use dynamic component technology to separate the performance-constrained modules from the flexibility-constrained modules so that different image viewing or processing technologies can be developed and maintained independently. We also develop a weakly coupled collaboration service, through which these image applications can communicate with each other or with third party applications. We applied this architecture in developing our product line and it works well. In our clinical sites, this architecture is applied not only in Radiology Department, but also in Ultrasonic, Surgery, Clinics, and Consultation Center. Giving that each concerned department has its particular requirements and business routines along with the facts that they all have different image processing technologies and image display devices, our workstations are still able to maintain high performance and high usability.

  5. Preliminary Study on Appearance-Based Detection of Anatomical Point Landmarks in Body Trunk CT Images

    NASA Astrophysics Data System (ADS)

    Nemoto, Mitsutaka; Nomura, Yukihiro; Hanaoka, Shohei; Masutani, Yoshitaka; Yoshikawa, Takeharu; Hayashi, Naoto; Yoshioka, Naoki; Ohtomo, Kuni

    Anatomical point landmarks as most primitive anatomical knowledge are useful for medical image understanding. In this study, we propose a detection method for anatomical point landmark based on appearance models, which include gray-level statistical variations at point landmarks and their surrounding area. The models are built based on results of Principal Component Analysis (PCA) of sample data sets. In addition, we employed generative learning method by transforming ROI of sample data. In this study, we evaluated our method with 24 data sets of body trunk CT images and obtained 95.8 ± 7.3 % of the average sensitivity in 28 landmarks.

  6. Deformable Medical Image Registration: A Survey

    PubMed Central

    Sotiras, Aristeidis; Davatzikos, Christos; Paragios, Nikos

    2013-01-01

    Deformable image registration is a fundamental task in medical image processing. Among its most important applications, one may cite: i) multi-modality fusion, where information acquired by different imaging devices or protocols is fused to facilitate diagnosis and treatment planning; ii) longitudinal studies, where temporal structural or anatomical changes are investigated; and iii) population modeling and statistical atlases used to study normal anatomical variability. In this paper, we attempt to give an overview of deformable registration methods, putting emphasis on the most recent advances in the domain. Additional emphasis has been given to techniques applied to medical images. In order to study image registration methods in depth, their main components are identified and studied independently. The most recent techniques are presented in a systematic fashion. The contribution of this paper is to provide an extensive account of registration techniques in a systematic manner. PMID:23739795

  7. Image integrity verification in medical information systems.

    PubMed

    Lenti, Jozsef; Lovanyi, Istvan

    2003-01-01

    In nowadays it is a major objective to protect healthcare information against unauthorized access. Comparing conventional and electronic management of medical images the later one demands much more complex security measures. We propose a new scenario for watermark data buildup and embedding which is independent from the applied watermarking technology. In our proposed method the embedded watermark data is dependant on image and patient information too. The proposed watermark buildup method provides watermark information where it is small in size and represents a unique digest of the image and image related data. The embedded data can be considered unique with high probability even if the same algorithm was used in different medical information systems. Described procedures ensure new, more secure links between image and related data, offering further perspectives in smartcard implementations. PMID:14664001

  8. Perspectives of medical X-ray imaging

    NASA Astrophysics Data System (ADS)

    Freudenberger, J.; Hell, E.; Knüpfer, W.

    2001-06-01

    While X-ray image intensifiers (XII), storage phosphor screens and film-screen systems are still the work horses of medical imaging, large flat panel solid state detectors using either scintillators and amorphous silicon photo diode arrays (FD-Si), or direct X-ray conversion in amorphous selenium are reaching maturity. The main advantage with respect to image quality and low patient dose of the XII and FD-Si systems is caused by the rise of the Detector Quantum Efficiency originating from the application of thick needle-structured phosphor X-ray absorbers. With the detectors getting closer to an optimal state, further progress in medical X-ray imaging requires an improvement of the usable source characteristics. The development of clinical monochromatic X-ray sources of high power would not only allow an improved contrast-to-dose ratio by allowing smaller average photon energies in applications but would also lead to new imaging techniques.

  9. Scale-Specific Multifractal Medical Image Analysis

    PubMed Central

    Braverman, Boris

    2013-01-01

    Fractal geometry has been applied widely in the analysis of medical images to characterize the irregular complex tissue structures that do not lend themselves to straightforward analysis with traditional Euclidean geometry. In this study, we treat the nonfractal behaviour of medical images over large-scale ranges by considering their box-counting fractal dimension as a scale-dependent parameter rather than a single number. We describe this approach in the context of the more generalized Rényi entropy, in which we can also compute the information and correlation dimensions of images. In addition, we describe and validate a computational improvement to box-counting fractal analysis. This improvement is based on integral images, which allows the speedup of any box-counting or similar fractal analysis algorithm, including estimation of scale-dependent dimensions. Finally, we applied our technique to images of invasive breast cancer tissue from 157 patients to show a relationship between the fractal analysis of these images over certain scale ranges and pathologic tumour grade (a standard prognosticator for breast cancer). Our approach is general and can be applied to any medical imaging application in which the complexity of pathological image structures may have clinical value. PMID:24023588

  10. Perfusion CT imaging of treatment response in oncology.

    PubMed

    Prezzi, Davide; Khan, Aisha; Goh, Vicky

    2015-12-01

    Perfusion CT was first described in the 1970s but has become accepted as a clinical technique in recent years. In oncological practice Perfusion CT allows the downstream effects of therapies on the tumour vasculature to be monitored. From the dynamic changes in tumour and vascular enhancement following intravenous iodinated contrast agent administration, qualitative and quantitative parameters may be derived that reflect tumour perfusion, blood volume, and microcirculatory changes with treatment. This review outlines the mechanisms of action of available therapies and state-of-the-art imaging practice. PMID:25864440

  11. Perfusion CT imaging of the liver: review of clinical applications

    PubMed Central

    Oğul, Hayri; Kantarcı, Mecit; Genç, Berhan; Pirimoğlu, Berhan; Çullu, Neşat; Kızrak, Yeşim; Yılmaz, Ömer; Karabulut, Nevzat

    2014-01-01

    Perfusion computed tomography (CT) has a great potential for determining hepatic and portal blood flow; it offers the advantages of quantitative determination of lesion hemodynamics, distinguishing malignant and benign processes, as well as providing morphological data. Many studies have reported the use of this method in the assessment of hepatic tumors, hepatic fibrosis associated with chronic liver disease, treatment response following radiotherapy and chemotherapy, and hepatic perfusion changes after radiological or surgical interventions. The main goal of liver perfusion imaging is to improve the accuracy in the characterization of liver disorders. In this study, we reviewed the clinical application of perfusion CT in various hepatic diseases. PMID:24834487

  12. Cardiovascular PET-CT imaging: a new frontier?

    PubMed

    Adamson, P D; Williams, M C; Newby, D E

    2016-07-01

    Cardiovascular positron-emission tomography combined with computed tomography (PET-CT) has recently emerged as an imaging technology with the potential to simultaneously describe both anatomical structures and physiological processes in vivo. The scope for clinical application of this technique is vast, but to date this promise has not been realised. Nonetheless, significant research activity is underway to explore these possibilities and it is likely that the knowledge gained will have important diagnostic and therapeutic implications in due course. This review provides a brief overview of the current state of cardiovascular PET-CT and the likely direction of future developments. PMID:26951964

  13. Multiscale medical image fusion in wavelet domain.

    PubMed

    Singh, Rajiv; Khare, Ashish

    2013-01-01

    Wavelet transforms have emerged as a powerful tool in image fusion. However, the study and analysis of medical image fusion is still a challenging area of research. Therefore, in this paper, we propose a multiscale fusion of multimodal medical images in wavelet domain. Fusion of medical images has been performed at multiple scales varying from minimum to maximum level using maximum selection rule which provides more flexibility and choice to select the relevant fused images. The experimental analysis of the proposed method has been performed with several sets of medical images. Fusion results have been evaluated subjectively and objectively with existing state-of-the-art fusion methods which include several pyramid- and wavelet-transform-based fusion methods and principal component analysis (PCA) fusion method. The comparative analysis of the fusion results has been performed with edge strength (Q), mutual information (MI), entropy (E), standard deviation (SD), blind structural similarity index metric (BSSIM), spatial frequency (SF), and average gradient (AG) metrics. The combined subjective and objective evaluations of the proposed fusion method at multiple scales showed the effectiveness and goodness of the proposed approach. PMID:24453868

  14. ROI extraction of chest CT images using adaptive opening filter

    NASA Astrophysics Data System (ADS)

    Yamada, Nobuhiro; Kubo, Mitsuru; Kawata, Yoshiki; Niki, Noboru; Eguchi, Kenji; Omatsu, Hironobu; Kakinuma, Ryutaro; Kaneko, Masahiro; Kusumoto, Masahiko; Nishiyama, Hiroyuki; Moriyama, Noriyuki

    2003-05-01

    We have already developed a prototype of computer-aided diagnosis (CAD) system that can automatically detect suspicious shadows from Chest CT images. But the CAD system cannot detect Ground-Grass-Attenuation perfectly. In many cases, this reason depends on the inaccurate extraction of the region of interests (ROI) that CAD system analyzes, so we need to improve it. In this paper, we propose a method of an accurate extraction of the ROI, and compare proposed method to ordinary method that have used in CAD system. Proposed Method is performed by application of the three steps. Firstly we extract lung area using threshold. Secondly we remove the slowly varying bias field using flexible Opening Filter. This Opening Filter is calculated by the combination of the ordinary opening value and the distribution which CT value and contrast follow. Finally we extract Region of Interest using fuzzy clustering. When we applied proposal method to Chest CT images, we got a good result in which ordinary method cannot achieve. In this study we used the Helical CT images that are obtained under the following measurement: 10mm beam width; 20mm/sec table speed; 120kV tube voltage; 50mA tube current; 10mm reconstruction interval.

  15. Nanotechnology-supported THz medical imaging

    PubMed Central

    Stylianou, Andreas; Talias, Michael A

    2013-01-01

    Over the last few decades, the achievements and progress in the field of medical imaging have dramatically enhanced the early detection and treatment of many pathological conditions. The development of new imaging modalities, especially non-ionising ones, which will improve prognosis, is of crucial importance. A number of novel imaging modalities have been developed but they are still in the initial stages of development and serious drawbacks obstruct them from offering their benefits to the medical field. In the 21 st century, it is believed that nanotechnology will highly influence our everyday life and dramatically change the world of medicine, including medical imaging. Here we discuss how nanotechnology, which is still in its infancy, can improve Terahertz (THz) imaging, an emerging imaging modality, and how it may find its way into real clinical applications. THz imaging is characterised by the use of non-ionising radiation and although it has the potential to be used in many biomedical fields, it remains in the field of basic research. An extensive review of the recent available literature shows how the current state of this emerging imaging modality can be transformed by nanotechnology. Innovative scientific concepts that use nanotechnology-based techniques to overcome some of the limitations of the use of THz imaging are discussed. We review a number of drawbacks, such as a low contrast mechanism, poor source performance and bulky THz systems, which characterise present THz medical imaging and suggest how they can be overcome through nanotechnology. Better resolution and higher detection sensitivity can also be achieved using nanotechnology techniques. PMID:24555052

  16. Bioresponsive nanosensors in medical imaging.

    PubMed

    Schellenberger, Eyk

    2010-02-01

    Superparamagnetic iron oxide nanoparticles have been established as sensitive probes for magnetic resonance imaging (MRI). While the majority of specific nanosensors are based on sterically stabilized iron oxide particles, the focus of this review is on the use of very small iron oxide particles (VSOPs) that are electrostatically stabilized by an anionic citrate acid shell. We used VSOPs to develop target-specific as well as protease-activatable nanosensors for molecular MRI. PMID:19846442

  17. Pros and cons of organ shielding for CT imaging.

    PubMed

    Samei, Ehsan

    2014-10-01

    With the increased importance of CT radiation dose to health care providers, patients and the general public, there is an increased responsibility to minimize patient dose effectively. Bismuth shields offer a simple strategy to reduce dose to certain anterior radiosensitive organs such as breasts and eyes. However, in order to reduce organ dose they must be used properly; improper use can lead to an actual increase in the patient dose. They also create a proportional increase in image noise in the section of the body adjacent to the shield and further reduce the quantitative precision of CT numbers. In addition, shielding can degrade the overall efficiency (by an order of approximately 10%) of the imaging process, reducing the theoretical image quality that can be expected from a certain level of patient dose. However, in spite of their significant disadvantages, there are certain clinical situations and practice considerations that provide qualified justification for their continued use. PMID:25304710

  18. Fast and Automatic Ultrasound Simulation from CT Images

    PubMed Central

    Yang, Jian; Liu, Yue; Wang, Yongtian

    2013-01-01

    Ultrasound is currently widely used in clinical diagnosis because of its fast and safe imaging principles. As the anatomical structures present in an ultrasound image are not as clear as CT or MRI. Physicians usually need advance clinical knowledge and experience to distinguish diseased tissues. Fast simulation of ultrasound provides a cost-effective way for the training and correlation of ultrasound and the anatomic structures. In this paper, a novel method is proposed for fast simulation of ultrasound from a CT image. A multiscale method is developed to enhance tubular structures so as to simulate the blood flow. The acoustic response of common tissues is generated by weighted integration of adjacent regions on the ultrasound propagation path in the CT image, from which parameters, including attenuation, reflection, scattering, and noise, are estimated simultaneously. The thin-plate spline interpolation method is employed to transform the simulation image between polar and rectangular coordinate systems. The Kaiser window function is utilized to produce integration and radial blurring effects of multiple transducer elements. Experimental results show that the developed method is very fast and effective, allowing realistic ultrasound to be fast generated. Given that the developed method is fully automatic, it can be utilized for ultrasound guided navigation in clinical practice and for training purpose. PMID:24348736

  19. Automatic labeling and segmentation of vertebrae in CT images

    NASA Astrophysics Data System (ADS)

    Rasoulian, Abtin; Rohling, Robert N.; Abolmaesumi, Purang

    2014-03-01

    Labeling and segmentation of the spinal column from CT images is a pre-processing step for a range of image- guided interventions. State-of-the art techniques have focused either on image feature extraction or template matching for labeling of the vertebrae followed by segmentation of each vertebra. Recently, statistical multi- object models have been introduced to extract common statistical characteristics among several anatomies. In particular, we have created models for segmentation of the lumbar spine which are robust, accurate, and computationally tractable. In this paper, we reconstruct a statistical multi-vertebrae pose+shape model and utilize it in a novel framework for labeling and segmentation of the vertebra in a CT image. We validate our technique in terms of accuracy of the labeling and segmentation of CT images acquired from 56 subjects. The method correctly labels all vertebrae in 70% of patients and is only one level off for the remaining 30%. The mean distance error achieved for the segmentation is 2.1 +/- 0.7 mm.

  20. Weighted medical image registration with automatic mask generation

    NASA Astrophysics Data System (ADS)

    Schumacher, Hanno; Franz, Astrid; Fischer, Bernd

    2006-03-01

    Registration of images is a crucial part of many medical imaging tasks. The problem is to find a transformation which aligns two given images. The resulting displacement fields may be for example described as a linear combination of pre-selected basis functions (parametric approach), or, as in our case, they may be computed as the solution of an associated partial differential equation (non-parametric approach). Here, the underlying functional consists of a smoothness term ensuring that the transformation is anatomically meaningful and a distance term describing the similarity between the two images. To be successful, the registration scheme has to be tuned for the problem under consideration. One way of incorporating user knowledge is the employment of weighting masks into the distance measure, and thereby enhancing or hiding dedicated image parts. In general, these masks are based on a given segmentation of both images. We present a method which generates a weighting mask for the second image, given the mask for the first image. The scheme is based on active contours and makes use of a gradient vector flow method. As an example application, we consider the registration of abdominal computer tomography (CT) images used for radiation therapy. The reference image is acquired well ahead of time and is used for setting up the radiation plan. The second image is taken just before the treatment and its processing is time-critical. We show that the proposed automatic mask generation scheme yields similar results as compared to the approach based on a pre-segmentation of both images. Hence for time-critical applications, as intra-surgery registration, we are able to significantly speed up the computation by avoiding a pre-segmentation of the second image.

  1. Medical imaging applications of amorphous silicon

    SciTech Connect

    Mireshghi, A.; Drewery, J.S.; Hong, W.S.; Jing, T.; Kaplan, S.N.; Lee, H.K.; Perez-Mendez, V.

    1994-07-01

    Two dimensional hydrogenated amorphous silicon (a-Si:H) pixel arrays are good candidates as flat-panel imagers for applications in medical imaging. Various performance characteristics of these imagers are reviewed and compared with currently used equipments. An important component in the a-Si:H imager is the scintillator screen. A new approach for fabrication of high resolution CsI(Tl) scintillator layers, appropriate for coupling to a-Si:H arrays, are presented. For nuclear medicine applications, a new a-Si:H based gamma camera is introduced and Monte Carlo simulation is used to evaluate its performance.

  2. Human airway measurement from CT images

    NASA Astrophysics Data System (ADS)

    Lee, Jaesung; Reeves, Anthony P.; Fotin, Sergei; Apanasovich, Tatiyana; Yankelevitz, David

    2008-03-01

    A wide range of pulmonary diseases, including common ones such as COPD, affect the airways. If the dimensions of airway can be measured with high confidence, the clinicians will be able to better diagnose diseases as well as monitor progression and response to treatment. In this paper, we introduce a method to assess the airway dimensions from CT scans, including the airway segments that are not oriented axially. First, the airway lumen is segmented and skeletonized, and subsequently each airway segment is identified. We then represent each airway segment using a segment-centric generalized cylinder model and assess airway lumen diameter (LD) and wall thickness (WT) for each segment by determining inner and outer wall boundaries. The method was evaluated on 14 healthy patients from a Weill Cornell database who had two scans within a 2 month interval. The corresponding airway segments were located in two scans and measured using the automated method. The total number of segments identified in both scans was 131. When 131 segments were considered altogether, the average absolute change over two scans was 0.31 mm for LD and 0.12 mm for WT, with 95% limits of agreement of [-0.85, 0.83] for LD and [-0.32, 0.26] for WT. The results were also analyzed on per-patient basis, and the average absolute change was 0.19 mm for LD and 0.05 mm for WT. 95% limits of agreement for per-patient changes were [-0.57, 0.47] for LD and [-0.16, 0.10] for WT.

  3. 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. PMID:26890880

  4. An integrated medical image database and retrieval system using a web application server.

    PubMed

    Cao, Pengyu; Hashiba, Masao; Akazawa, Kouhei; Yamakawa, Tomoko; Matsuto, Takayuki

    2003-08-01

    We developed an Integrated Medical Image Database and Retrieval System (INIS) for easy access by medical staff. The INIS mainly consisted of four parts: specific servers to save medical images from multi-vendor modalities of CT, MRI, CR, ECG and endoscopy; an integrated image database (DB) server to save various kinds of images in a DICOM format; a Web application server to connect clients to the integrated image DB and the Web browser terminals connected to an HIS system. The INIS provided a common screen design to retrieve CT, MRI, CR, endoscopic and ECG images, and radiological reports, which would allow doctors to retrieve radiological images and corresponding reports, or ECG images of a patient simultaneously on a screen. Doctors working in internal medicine on average accessed information 492 times a month. Doctors working in cardiological and gastroenterological accessed information 308 times a month. Using the INIS, medical staff could browse all or parts of a patient's medical images and reports. PMID:12909158

  5. CT Scanning Imaging Method Based on a Spherical Trajectory

    PubMed Central

    2016-01-01

    In industrial computed tomography (CT), the mismatch between the X-ray energy and the effective thickness makes it difficult to ensure the integrity of projection data using the traditional scanning model, because of the limitations of the object’s complex structure. So, we have developed a CT imaging method that is based on a spherical trajectory. Considering an unrestrained trajectory for iterative reconstruction, an iterative algorithm can be used to realise the CT reconstruction of a spherical trajectory for complete projection data only. Also, an inclined circle trajectory is used as an example of a spherical trajectory to illustrate the accuracy and feasibility of this new scanning method. The simulation results indicate that the new method produces superior results for a larger cone-beam angle, a limited angle and tabular objects compared with traditional circle trajectory scanning. PMID:26934744

  6. CT Scanning Imaging Method Based on a Spherical Trajectory.

    PubMed

    Chen, Ping; Han, Yan; Gui, Zhiguo

    2016-01-01

    In industrial computed tomography (CT), the mismatch between the X-ray energy and the effective thickness makes it difficult to ensure the integrity of projection data using the traditional scanning model, because of the limitations of the object's complex structure. So, we have developed a CT imaging method that is based on a spherical trajectory. Considering an unrestrained trajectory for iterative reconstruction, an iterative algorithm can be used to realise the CT reconstruction of a spherical trajectory for complete projection data only. Also, an inclined circle trajectory is used as an example of a spherical trajectory to illustrate the accuracy and feasibility of this new scanning method. The simulation results indicate that the new method produces superior results for a larger cone-beam angle, a limited angle and tabular objects compared with traditional circle trajectory scanning. PMID:26934744

  7. Fast volume rendering for medical image.

    PubMed

    Ying, Hu; Xin-He, Xu

    2005-01-01

    In orders to improve the rendering speed of ray casting and make this technique a practical routine in medical applications, two new and improved techniques are described in this paper. First, an integrated method using "proximity clouds" technique is applied to speed up ray casting. The second technique for speeding up the 3D rendering is done through a parallel implementation based on "single computer multi CPU" model Four groups of CT data sets have been used to validate the improvement of the rendering speed. The result shown that the interactive rendering speed is up to 6-10 fps, which is almost real-time making our algorithm practical in medical visualization routine. PMID:17281409

  8. Medical image registration using fuzzy theory.

    PubMed

    Pan, Meisen; Tang, Jingtian; Xiong, Qi

    2012-01-01

    Mutual information (MI)-based registration, which uses MI as the similarity measure, is a representative method in medical image registration. It has an excellent robustness and accuracy, but with the disadvantages of a large amount of calculation and a long processing time. In this paper, by computing the medical image moments, the centroid is acquired. By applying fuzzy c-means clustering, the coordinates of the medical image are divided into two clusters to fit a straight line, and the rotation angles of the reference and floating images are computed, respectively. Thereby, the initial values for registering the images are determined. When searching the optimal geometric transformation parameters, we put forward the two new concepts of fuzzy distance and fuzzy signal-to-noise ratio (FSNR), and we select FSNR as the similarity measure between the reference and floating images. In the experiments, the Simplex method is chosen as multi-parameter optimisation. The experimental results show that this proposed method has a simple implementation, a low computational cost, a fast registration and good registration accuracy. Moreover, it can effectively avoid trapping into the local optima. It is adapted to both mono-modality and multi-modality image registrations. PMID:21442490

  9. Development of a high-speed CT imaging system using EMCCD camera

    NASA Astrophysics Data System (ADS)

    Thacker, Samta C.; Yang, Kai; Packard, Nathan; Gaysinskiy, Valeriy; Burkett, George; Miller, Stuart; Boone, John M.; Nagarkar, Vivek

    2009-02-01

    The limitations of current CCD-based microCT X-ray imaging systems arise from two important factors. First, readout speeds are curtailed in order to minimize system read noise, which increases significantly with increasing readout rates. Second, the afterglow associated with commercial scintillator films can introduce image lag, leading to substantial artifacts in reconstructed images, especially when the detector is operated at several hundred frames/second (fps). For high speed imaging systems, high-speed readout electronics and fast scintillator films are required. This paper presents an approach to developing a high-speed CT detector based on a novel, back-thinned electron-multiplying CCD (EMCCD) coupled to various bright, high resolution, low afterglow films. The EMCCD camera, when operated in its binned mode, is capable of acquiring data at up to 300 fps with reduced imaging area. CsI:Tl,Eu and ZnSe:Te films, recently fabricated at RMD, apart from being bright, showed very good afterglow properties, favorable for high-speed imaging. Since ZnSe:Te films were brighter than CsI:Tl,Eu films, for preliminary experiments a ZnSe:Te film was coupled to an EMCCD camera at UC Davis Medical Center. A high-throughput tungsten anode X-ray generator was used, as the X-ray fluence from a mini- or micro-focus source would be insufficient to achieve high-speed imaging. A euthanized mouse held in a glass tube was rotated 360 degrees in less than 3 seconds, while radiographic images were recorded at various readout rates (up to 300 fps); images were reconstructed using a conventional Feldkamp cone-beam reconstruction algorithm. We have found that this system allows volumetric CT imaging of small animals in approximately two seconds at ~110 to 190 μm resolution, compared to several minutes at 160 μm resolution needed for the best current systems.

  10. PET/CT image registration: Preliminary tests for its application to clinical dosimetry in radiotherapy

    SciTech Connect

    Banos-Capilla, M. C.; Garcia, M. A.; Bea, J.; Pla, C.; Larrea, L.; Lopez, E.

    2007-06-15

    The quality of dosimetry in radiotherapy treatment requires the accurate delimitation of the gross tumor volume. This can be achieved by complementing the anatomical detail provided by CT images through fusion with other imaging modalities that provide additional metabolic and physiological information. Therefore, use of multiple imaging modalities for radiotherapy treatment planning requires an accurate image registration method. This work describes tests carried out on a Discovery LS positron emission/computed tomography (PET/CT) system by General Electric Medical Systems (GEMS), for its later use to obtain images to delimit the target in radiotherapy treatment. Several phantoms have been used to verify image correlation, in combination with fiducial markers, which were used as a system of external landmarks. We analyzed the geometrical accuracy of two different fusion methods with the images obtained with these phantoms. We first studied the fusion method used by the PET/CT system by GEMS (hardware fusion) on the basis that there is satisfactory coincidence between the reconstruction centers in CT and PET systems; and secondly the fiducial fusion, a registration method, by means of least-squares fitting algorithm of a landmark points system. The study concluded with the verification of the centroid position of some phantom components in both imaging modalities. Centroids were estimated through a calculation similar to center-of-mass, weighted by the value of the CT number and the uptake intensity in PET. The mean deviations found for the hardware fusion method were: vertical bar {delta}x vertical bar {+-}{sigma}=3.3 mm{+-}1.0 mm and vertical bar {delta}y vertical bar {+-}{sigma}=3.6 mm{+-}1.0 mm. These values were substantially improved upon applying fiducial fusion based on external landmark points: vertical bar {delta}x vertical bar {+-}{sigma}=0.7 mm{+-}0.8 mm and vertical bar {delta}y vertical bar {+-}{sigma}=0.3 mm{+-}1.7 mm. We also noted that differences

  11. Cone-Beam CT with a Flat-Panel Detector: From Image Science to Image-Guided Surgery

    PubMed Central

    Siewerdsen, Jeffrey H.

    2011-01-01

    The development of large-area flat-panel x-ray detectors (FPDs) has spurred investigation in a spectrum of advanced medical imaging applications, including tomosynthesis and cone-beam CT (CBCT). Recent research has extended image quality metrics and theoretical models to such applications, providing a quantitative foundation for the assessment of imaging performance as well as a general framework for the design, optimization, and translation of such technologies to new applications. For example, cascaded systems models of Fourier domain metrics, such as noise-equivalent quanta (NEQ), have been extended to these modalities to describe the propagation of signal and noise through the image acquisition and reconstruction chain and to quantify the factors that govern spatial resolution, image noise, and detectability. Moreover, such models have demonstrated basic agreement with human observer performance for a broad range of imaging conditions and imaging tasks. These developments in image science have formed a foundation for the knowledgeable development and translation of CBCT to new applications in image-guided interventions - for example, CBCT implemented on a mobile surgical C-arm for intraoperative 3D imaging. The ability to acquire high-quality 3D images on demand during surgical intervention overcomes conventional limitations of surgical guidance in the context of preoperative images alone. A prototype mobile C-arm developed in academic-industry partnership demonstrates CBCT with low radiation dose, sub-mm spatial resolution, and soft-tissue visibility potentially approaching that of diagnostic CT. Integration of the 3D imaging system with real-time tracking, deformable registration, endoscopic video, and 3D visualization offers a promising addition to the surgical arsenal in interventions ranging from head-and-neck / skull base surgery to spine, orthopaedic, thoracic, and abdominal surgeries. Cadaver studies show the potential for significant boosts in surgical

  12. Cone-beam CT with a flat-panel detector: From image science to image-guided surgery

    NASA Astrophysics Data System (ADS)

    Siewerdsen, Jeffrey H.

    2011-08-01

    The development of large-area flat-panel X-ray detectors (FPDs) has spurred investigation in a spectrum of advanced medical imaging applications, including tomosynthesis and cone-beam CT (CBCT). Recent research has extended image quality metrics and theoretical models to such applications, providing a quantitative foundation for the assessment of imaging performance as well as a general framework for the design, optimization, and translation of such technologies to new applications. For example, cascaded systems models of the Fourier domain metrics, such as noise-equivalent quanta (NEQ), have been extended to these modalities to describe the propagation of signal and noise through the image acquisition and reconstruction chain and to quantify the factors that govern spatial resolution, image noise, and detectability. Moreover, such models have demonstrated basic agreement with human observer performance for a broad range of imaging conditions and imaging tasks. These developments in image science have formed a foundation for the knowledgeable development and translation of CBCT to new applications in image-guided interventions—for example, CBCT implemented on a mobile surgical C-arm for intraoperative 3D imaging. The ability to acquire high-quality 3D images on demand during surgical intervention overcomes conventional limitations of surgical guidance in the context of preoperative images alone. A prototype mobile C-arm developed in academic-industry partnership demonstrates CBCT with low radiation dose, sub-mm spatial resolution, and soft-tissue visibility potentially approaching that of diagnostic CT. Integration of the 3D imaging system with real-time tracking, deformable registration, endoscopic video, and 3D visualization offers a promising addition to the surgical arsenal in interventions ranging from head-and-neck/skull base surgery to spine, orthopaedic, thoracic, and abdominal surgeries. Cadaver studies show the potential for significant boosts in

  13. Cone-Beam CT with a Flat-Panel Detector: From Image Science to Image-Guided Surgery.

    PubMed

    Siewerdsen, Jeffrey H

    2011-08-21

    The development of large-area flat-panel x-ray detectors (FPDs) has spurred investigation in a spectrum of advanced medical imaging applications, including tomosynthesis and cone-beam CT (CBCT). Recent research has extended image quality metrics and theoretical models to such applications, providing a quantitative foundation for the assessment of imaging performance as well as a general framework for the design, optimization, and translation of such technologies to new applications. For example, cascaded systems models of Fourier domain metrics, such as noise-equivalent quanta (NEQ), have been extended to these modalities to describe the propagation of signal and noise through the image acquisition and reconstruction chain and to quantify the factors that govern spatial resolution, image noise, and detectability. Moreover, such models have demonstrated basic agreement with human observer performance for a broad range of imaging conditions and imaging tasks. These developments in image science have formed a foundation for the knowledgeable development and translation of CBCT to new applications in image-guided interventions - for example, CBCT implemented on a mobile surgical C-arm for intraoperative 3D imaging. The ability to acquire high-quality 3D images on demand during surgical intervention overcomes conventional limitations of surgical guidance in the context of preoperative images alone. A prototype mobile C-arm developed in academic-industry partnership demonstrates CBCT with low radiation dose, sub-mm spatial resolution, and soft-tissue visibility potentially approaching that of diagnostic CT. Integration of the 3D imaging system with real-time tracking, deformable registration, endoscopic video, and 3D visualization offers a promising addition to the surgical arsenal in interventions ranging from head-and-neck / skull base surgery to spine, orthopaedic, thoracic, and abdominal surgeries. Cadaver studies show the potential for significant boosts in surgical

  14. High definition ultrasound imaging for battlefield medical applications

    SciTech Connect

    Kwok, K.S.; Morimoto, A.K.; Kozlowski, D.M.; Krumm, J.C.; Dickey, F.M.; Rogers, B; Walsh, N.

    1996-06-23

    A team has developed an improved resolution ultrasound system for low cost diagnostics. This paper describes the development of an ultrasound based imaging system capable of generating 3D images showing surface and subsurface tissue and bone structures. We include results of a comparative study between images obtained from X-Ray Computed Tomography (CT) and ultrasound. We found that the quality of ultrasound images compares favorably with those from CT. Volumetric and surface data extracted from these images were within 7% of the range between ultrasound and CT scans. We also include images of porcine abdominal scans from two different sets of animal trials.

  15. Quantitative imaging features: extension of the oncology medical image database

    NASA Astrophysics Data System (ADS)

    Patel, M. N.; Looney, P. T.; Young, K. C.; Halling-Brown, M. D.

    2015-03-01

    Radiological imaging is fundamental within the healthcare industry and has become routinely adopted for diagnosis, disease monitoring and treatment planning. With the advent of digital imaging modalities and the rapid growth in both diagnostic and therapeutic imaging, the ability to be able to harness this large influx of data is of paramount importance. The Oncology Medical Image Database (OMI-DB) was created to provide a centralized, fully annotated dataset for research. The database contains both processed and unprocessed images, associated data, and annotations and where applicable expert determined ground truths describing features of interest. Medical imaging provides the ability to detect and localize many changes that are important to determine whether a disease is present or a therapy is effective by depicting alterations in anatomic, physiologic, biochemical or molecular processes. Quantitative imaging features are sensitive, specific, accurate and reproducible imaging measures of these changes. Here, we describe an extension to the OMI-DB whereby a range of imaging features and descriptors are pre-calculated using a high throughput approach. The ability to calculate multiple imaging features and data from the acquired images would be valuable and facilitate further research applications investigating detection, prognosis, and classification. The resultant data store contains more than 10 million quantitative features as well as features derived from CAD predictions. Theses data can be used to build predictive models to aid image classification, treatment response assessment as well as to identify prognostic imaging biomarkers.

  16. Three modality image registration of brain SPECT/CT and MR images for quantitative analysis of dopamine transporter imaging

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Yuzuho; Takeda, Yuta; Hara, Takeshi; Zhou, Xiangrong; Matsusako, Masaki; Tanaka, Yuki; Hosoya, Kazuhiko; Nihei, Tsutomu; Katafuchi, Tetsuro; Fujita, Hiroshi

    2016-03-01

    Important features in Parkinson's disease (PD) are degenerations and losses of dopamine neurons in corpus striatum. 123I-FP-CIT can visualize activities of the dopamine neurons. The activity radio of background to corpus striatum is used for diagnosis of PD and Dementia with Lewy Bodies (DLB). The specific activity can be observed in the corpus striatum on SPECT images, but the location and the shape of the corpus striatum on SPECT images only are often lost because of the low uptake. In contrast, MR images can visualize the locations of the corpus striatum. The purpose of this study was to realize a quantitative image analysis for the SPECT images by using image registration technique with brain MR images that can determine the region of corpus striatum. In this study, the image fusion technique was used to fuse SPECT and MR images by intervening CT image taken by SPECT/CT. The mutual information (MI) for image registration between CT and MR images was used for the registration. Six SPECT/CT and four MR scans of phantom materials are taken by changing the direction. As the results of the image registrations, 16 of 24 combinations were registered within 1.3mm. By applying the approach to 32 clinical SPECT/CT and MR cases, all of the cases were registered within 0.86mm. In conclusions, our registration method has a potential in superimposing MR images on SPECT images.

  17. CT Imaging of Coronary Stents: Past, Present, and Future

    PubMed Central

    Mahnken, Andreas H.

    2012-01-01

    Coronary stenting became a mainstay in coronary revascularization therapy. Despite tremendous advances in therapy, in-stent restenosis (ISR) remains a key problem after coronary stenting. Coronary CT angiography evolved as a valuable tool in the diagnostic workup of patients after coronary revascularization therapy. It has a negative predictive value in the range of 98% for ruling out significant ISR. As CT imaging of coronary stents depends on patient and stent characteristics, patient selection is crucial for success. Ideal candidates have stents with a diameter of 3 mm and more. Nevertheless, even with most recent CT scanners, about 8% of stents are not accessible mostly due to blooming or motion artifacts. While the diagnosis of ISR is currently based on the visual assessment of the stent lumen, functional information on the hemodynamic significance of in-stent stenosis became available with the most recent generation of dual source CT scanners. This paper provides a comprehensive overview on previous developments, current techniques, and clinical evidence for cardiac CT in patients with coronary artery stents. PMID:22997590

  18. Gallium-68 EDTA PET/CT for Renal Imaging.

    PubMed

    Hofman, Michael S; Hicks, Rodney J

    2016-09-01

    Nuclear medicine renal imaging provides important functional data to assist in the diagnosis and management of patients with a variety of renal disorders. Physiologically stable metal chelates like ethylenediaminetetraacetic acid (EDTA) and diethylenetriamine penta-acetate (DTPA) are excreted by glomerular filtration and have been radiolabelled with a variety of isotopes for imaging glomerular filtration and quantitative assessment of glomerular filtration rate. Gallium-68 ((68)Ga) EDTA PET usage predates Technetium-99m ((99m)Tc) renal imaging, but virtually disappeared with the widespread adoption of gamma camera technology that was not optimal for imaging positron decay. There is now a reemergence of interest in (68)Ga owing to the greater availability of PET technology and use of (68)Ga to label other radiotracers. (68)Ga EDTA can be used a substitute for (99m)Tc DTPA for wide variety of clinical indications. A key advantage of PET for renal imaging over conventional scintigraphy is 3-dimensional dynamic imaging, which is particularly helpful in patients with complex anatomy in whom planar imaging may be nondiagnostic or difficult to interpret owing to overlying structures containing radioactive urine that cannot be differentiated. Other advantages include accurate and absolute (rather than relative) camera-based quantification, superior spatial and temporal resolution and integrated multislice CT providing anatomical correlation. Furthermore, the (68)Ga generator enables on-demand production at low cost, with no additional patient radiation exposure compared with conventional scintigraphy. Over the past decade, we have employed (68)Ga EDTA PET/CT primarily to answer difficult clinical questions in patients in whom other modalities have failed, particularly when it was envisaged that dynamic 3D imaging would be of assistance. We have also used it as a substitute for (99m)Tc DTPA if unavailable owing to supply issues, and have additionally examined the role of

  19. Validating automatic semantic annotation of anatomy in DICOM CT images

    NASA Astrophysics Data System (ADS)

    Pathak, Sayan D.; Criminisi, Antonio; Shotton, Jamie; White, Steve; Robertson, Duncan; Sparks, Bobbi; Munasinghe, Indeera; Siddiqui, Khan

    2011-03-01

    In the current health-care environment, the time available for physicians to browse patients' scans is shrinking due to the rapid increase in the sheer number of images. This is further aggravated by mounting pressure to become more productive in the face of decreasing reimbursement. Hence, there is an urgent need to deliver technology which enables faster and effortless navigation through sub-volume image visualizations. Annotating image regions with semantic labels such as those derived from the RADLEX ontology can vastly enhance image navigation and sub-volume visualization. This paper uses random regression forests for efficient, automatic detection and localization of anatomical structures within DICOM 3D CT scans. A regression forest is a collection of decision trees which are trained to achieve direct mapping from voxels to organ location and size in a single pass. This paper focuses on comparing automated labeling with expert-annotated ground-truth results on a database of 50 highly variable CT scans. Initial investigations show that regression forest derived localization errors are smaller and more robust than those achieved by state-of-the-art global registration approaches. The simplicity of the algorithm's context-rich visual features yield typical runtimes of less than 10 seconds for a 5123 voxel DICOM CT series on a single-threaded, single-core machine running multiple trees; each tree taking less than a second. Furthermore, qualitative evaluation demonstrates that using the detected organs' locations as index into the image volume improves the efficiency of the navigational workflow in all the CT studies.

  20. Incorporating detection tasks into the assessment of CT image quality

    NASA Astrophysics Data System (ADS)

    Scalzetti, E. M.; Huda, W.; Ogden, K. M.; Khan, M.; Roskopf, M. L.; Ogden, D.

    2006-03-01

    The purpose of this study was to compare traditional and task dependent assessments of CT image quality. Chest CT examinations were obtained with a standard protocol for subjects participating in a lung cancer-screening project. Images were selected for patients whose weight ranged from 45 kg to 159 kg. Six ABR certified radiologists subjectively ranked these images using a traditional six-point ranking scheme that ranged from 1 (inadequate) to 6 (excellent). Three subtle diagnostic tasks were identified: (1) a lung section containing a sub-centimeter nodule of ground-glass opacity in an upper lung (2) a mediastinal section with a lymph node of soft tissue density in the mediastinum; (3) a liver section with a rounded low attenuation lesion in the liver periphery. Each observer was asked to estimate the probability of detecting each type of lesion in the appropriate CT section using a six-point scale ranging from 1 (< 10%) to 6 (> 90%). Traditional and task dependent measures of image quality were plotted as a function of patient weight. For the lung section, task dependent evaluations were very similar to those obtained using the traditional scoring scheme, but with larger inter-observer differences. Task dependent evaluations for the mediastinal section showed no obvious trend with subject weight, whereas there the traditional score decreased from ~4.9 for smaller subjects to ~3.3 for the larger subjects. Task dependent evaluations for the liver section showed a decreasing trend from ~4.1 for the smaller subjects to ~1.9 for the larger subjects, whereas the traditional evaluation had a markedly narrower range of scores. A task-dependent method of assessing CT image quality can be implemented with relative ease, and is likely to be more meaningful in the clinical setting.

  1. Cochlear anatomy using micro computed tomography (μCT) imaging

    NASA Astrophysics Data System (ADS)

    Kim, Namkeun; Yoon, Yongjin; Steele, Charles; Puria, Sunil

    2008-02-01

    A novel micro computed tomography (μCT) image processing method was implemented to measure anatomical features of the gerbil and chinchilla cochleas, taking into account the bent modailosis axis. Measurements were made of the scala vestibule (SV) area, the scala tympani (SV) area, and the basilar membrane (BM) width using prepared cadaveric temporal bones. 3-D cochlear structures were obtained from the scanned images using a process described in this study. It was necessary to consider the sharp curvature of mododailosis axis near the basal region. The SV and ST areas were calculated from the μCT reconstructions and compared with existing data obtained by Magnetic Resonance Microscopy (MRM), showing both qualitative and quantitative agreement. In addition to this, the width of the BM, which is the distance between the primary and secondary osseous spiral laminae, is calculated for the two animals and compared with previous data from the MRM method. For the gerbil cochlea, which does not have much cartilage in the osseous spiral lamina, the μCT-based BM width measurements show good agreement with previous data. The chinchilla BM, which contains more cartilage in the osseous spiral lamina than the gerbil, shows a large difference in the BM widths between the μCT and MRM methods. The SV area, ST area, and BM width measurements from this study can be used in building an anatomically based mathematical cochlear model.

  2. Segmentation of the ovine lung in 3D CT Images

    NASA Astrophysics Data System (ADS)

    Shi, Lijun; Hoffman, Eric A.; Reinhardt, Joseph M.

    2004-04-01

    Pulmonary CT images can provide detailed information about the regional structure and function of the respiratory system. Prior to any of these analyses, however, the lungs must be identified in the CT data sets. A popular animal model for understanding lung physiology and pathophysiology is the sheep. In this paper we describe a lung segmentation algorithm for CT images of sheep. The algorithm has two main steps. The first step is lung extraction, which identifies the lung region using a technique based on optimal thresholding and connected components analysis. The second step is lung separation, which separates the left lung from the right lung by identifying the central fissure using an anatomy-based method incorporating dynamic programming and a line filter algorithm. The lung segmentation algorithm has been validated by comparing our automatic method to manual analysis for five pulmonary CT datasets. The RMS error between the computer-defined and manually-traced boundary is 0.96 mm. The segmentation requires approximately 10 minutes for a 512x512x400 dataset on a PC workstation (2.40 GHZ CPU, 2.0 GB RAM), while it takes human observer approximately two hours to accomplish the same task.

  3. The influence of respiratory motion on CT image volume definition

    SciTech Connect

    Rodríguez-Romero, Ruth Castro-Tejero, Pablo

    2014-04-15

    Purpose: Radiotherapy treatments are based on geometric and density information acquired from patient CT scans. It is well established that breathing motion during scan acquisition induces motion artifacts in CT images, which can alter the size, shape, and density of a patient's anatomy. The aim of this work is to examine and evaluate the impact of breathing motion on multislice CT imaging with respiratory synchronization (4DCT) and without it (3DCT). Methods: A specific phantom with a movable insert was used. Static and dynamic phantom acquisitions were obtained with a multislice CT. Four sinusoidal breath patterns were simulated to move known geometric structures longitudinally. Respiratory synchronized acquisitions (4DCT) were performed to generate images during inhale, intermediate, and exhale phases using prospective and retrospective techniques. Static phantom data were acquired in helical and sequential mode to define a baseline for each type of respiratory 4DCT technique. Taking into account the fact that respiratory 4DCT is not always available, 3DCT helical image studies were also acquired for several CT rotation periods. To study breath and acquisition coupling when respiratory 4DCT was not performed, the beginning of the CT image acquisition was matched with inhale, intermediate, or exhale respiratory phases, for each breath pattern. Other coupling scenarios were evaluated by simulating different phantom and CT acquisition parameters. Motion induced variations in shape and density were quantified by automatic threshold volume generation and Dice similarity coefficient calculation. The structure mass center positions were also determined to make a comparison with their theoretical expected position. Results: 4DCT acquisitions provided volume and position accuracies within ±3% and ±2 mm for structure dimensions >2 cm, breath amplitude ≤15 mm, and breath period ≥3 s. The smallest object (1 cm diameter) exceeded 5% volume variation for the breath

  4. Live minimal path for interactive segmentation of medical images

    NASA Astrophysics Data System (ADS)

    Chartrand, Gabriel; Tang, An; Chav, Ramnada; Cresson, Thierry; Chantrel, Steeve; De Guise, Jacques A.

    2015-03-01

    Medical image segmentation is nowadays required for medical device development and in a growing number of clinical and research applications. Since dedicated automatic segmentation methods are not always available, generic and efficient interactive tools can alleviate the burden of manual segmentation. In this paper we propose an interactive segmentation tool based on image warping and minimal path segmentation that is efficient for a wide variety of segmentation tasks. While the user roughly delineates the desired organs boundary, a narrow band along the cursors path is straightened, providing an ideal subspace for feature aligned filtering and minimal path algorithm. Once the segmentation is performed on the narrow band, the path is warped back onto the original image, precisely delineating the desired structure. This tool was found to have a highly intuitive dynamic behavior. It is especially efficient against misleading edges and required only coarse interaction from the user to achieve good precision. The proposed segmentation method was tested for 10 difficult liver segmentations on CT and MRI images, and the resulting 2D overlap Dice coefficient was 99% on average..

  5. Absolutely lossless compression of medical images.

    PubMed

    Ashraf, Robina; Akbar, Muhammad

    2005-01-01

    Data in medical images is very large and therefore for storage and/or transmission of these images, compression is essential. A method is proposed which provides high compression ratios for radiographic images with no loss of diagnostic quality. In the approach an image is first compressed at a high compression ratio but with loss, and the error image is then compressed losslessly. The resulting compression is not only strictly lossless, but also expected to yield a high compression ratio, especially if the lossy compression technique is good. A neural network vector quantizer (NNVQ) is used as a lossy compressor, while for lossless compression Huffman coding is used. Quality of images is evaluated by comparing with standard compression techniques available. PMID:17281110

  6. Computer-aided diagnosis workstation and telemedicine network system for chest diagnosis based on multislice CT images

    NASA Astrophysics Data System (ADS)

    Satoh, Hitoshi; Niki, Noboru; Eguchi, Kenji; Ohmatsu, Hironobu; Kakinuma, Ryutaru; Moriyama, Noriyuki

    2009-02-01

    Mass screening based on multi-helical CT images requires a considerable number of images to be read. It is this time-consuming step that makes the use of helical CT for mass screening impractical at present. Moreover, the doctor who diagnoses a medical image is insufficient in Japan. To overcome these problems, we have provided diagnostic assistance methods to medical screening specialists by developing a lung cancer screening algorithm that automatically detects suspected lung cancers in helical CT images, a coronary artery calcification screening algorithm that automatically detects suspected coronary artery calcification and a vertebra body analysis algorithm for quantitative evaluation of osteoporosis likelihood by using helical CT scanner for the lung cancer mass screening. The functions to observe suspicious shadow in detail are provided in computer-aided diagnosis workstation with these screening algorithms. We also have developed the telemedicine network by using Web medical image conference system with the security improvement of images transmission, Biometric fingerprint authentication system and Biometric face authentication system. Biometric face authentication used on site of telemedicine makes "Encryption of file" and "Success in login" effective. As a result, patients' private information is protected. We can share the screen of Web medical image conference system from two or more web conference terminals at the same time. An opinion can be exchanged mutually by using a camera and a microphone that are connected with workstation. Based on these diagnostic assistance methods, we have developed a new computer-aided workstation and a new telemedicine network that can display suspected lesions three-dimensionally in a short time. The results of this study indicate that our radiological information system without film by using computer-aided diagnosis workstation and our telemedicine network system can increase diagnostic speed, diagnostic accuracy and

  7. Resolution enhancement in medical ultrasound imaging

    PubMed Central

    Ploquin, Marie; Basarab, Adrian; Kouamé, Denis

    2015-01-01

    Abstract. Image resolution enhancement is a problem of considerable interest in all medical imaging modalities. Unlike general purpose imaging or video processing, for a very long time, medical image resolution enhancement has been based on optimization of the imaging devices. Although some recent works purport to deal with image postprocessing, much remains to be done regarding medical image enhancement via postprocessing, especially in ultrasound imaging. We face a resolution improvement issue in the case of medical ultrasound imaging. We propose to investigate this problem using multidimensional autoregressive (AR) models. Noting that the estimation of the envelope of an ultrasound radio frequency (RF) signal is very similar to the estimation of classical Fourier-based power spectrum estimation, we theoretically show that a domain change and a multidimensional AR model can be used to achieve super-resolution in ultrasound imaging provided the order is estimated correctly. Here, this is done by means of a technique that simultaneously estimates the order and the parameters of a multidimensional model using relevant regression matrix factorization. Doing so, the proposed method specifically fits ultrasound imaging and provides an estimated envelope. Moreover, an expression that links the theoretical image resolution to both the image acquisition features (such as the point spread function) and a postprocessing feature (the AR model) order is derived. The overall contribution of this work is threefold. First, it allows for automatic resolution improvement. Through a simple model and without any specific manual algorithmic parameter tuning, as is used in common methods, the proposed technique simply and exclusively uses the ultrasound RF signal as input and provides the improved B-mode as output. Second, it allows for the a priori prediction of the improvement in resolution via the knowledge of the parametric model order before actual processing. Finally, to achieve

  8. Medical Imaging with Ultrasound: Some Basic Physics.

    ERIC Educational Resources Information Center

    Gosling, R.

    1989-01-01

    Discussed are medical applications of ultrasound. The physics of the wave nature of ultrasound including its propagation and production, return by the body, spatial and contrast resolution, attenuation, image formation using pulsed echo ultrasound techniques, measurement of velocity and duplex scanning are described. (YP)

  9. Beat-Frequency/Microsphere Medical Ultrasonic Imaging

    NASA Technical Reports Server (NTRS)

    Yost, William T.; Cantrell, John H.; Pretlow, Robert A., III

    1995-01-01

    Medical ultrasonic imaging system designed to provide quantitative data on various flows of blood in chambers, blood vessels, muscles, and tissues of heart. Sensitive enough to yield readings on flows of blood in heart even when microspheres used as ultrasonic contrast agents injected far from heart and diluted by circulation of blood elsewhere in body.

  10. Active contour based segmentation of resected livers in CT images

    NASA Astrophysics Data System (ADS)

    Oelmann, Simon; Oyarzun Laura, Cristina; Drechsler, Klaus; Wesarg, Stefan

    2015-03-01

    The majority of state of the art segmentation algorithms are able to give proper results in healthy organs but not in pathological ones. However, many clinical applications require an accurate segmentation of pathological organs. The determination of the target boundaries for radiotherapy or liver volumetry calculations are examples of this. Volumetry measurements are of special interest after tumor resection for follow up of liver regrow. The segmentation of resected livers presents additional challenges that were not addressed by state of the art algorithms. This paper presents a snakes based algorithm specially developed for the segmentation of resected livers. The algorithm is enhanced with a novel dynamic smoothing technique that allows the active contour to propagate with different speeds depending on the intensities visible in its neighborhood. The algorithm is evaluated in 6 clinical CT images as well as 18 artificial datasets generated from additional clinical CT images.

  11. PET and PET/CT imaging of skeletal metastases

    PubMed Central

    2010-01-01

    Abstract Bone scintigraphy augmented with radiographs or cross-sectional imaging, such as computed tomography (CT) or magnetic resonance imaging (MRI), has remained the commonest method to diagnose and follow up skeletal metastases. However, bone scintigraphy is associated with relatively poor spatial resolution, limited diagnostic specificity and reduced sensitivity for bone marrow disease. It also shows limited diagnostic accuracy in assessing response to therapy in a clinically useful time period. With the advent of hybrid positron emission tomography (PET)/CT scanners there has been an increasing interest in using various PET tracers to evaluate skeletal disease including [18F]fluoride (NaF) as a bone-specific tracer and [18F]fluorodeoxyglucose and [18F]choline as tumour-specific tracers. There is also early work exploring the receptor status of skeletal metastases with somatostatin receptor analogues. This review describes the potential utility of these tracers in the assessment of skeletal metastases. PMID:20663736

  12. A Novel Technique for Prealignment in Multimodality Medical Image Registration

    PubMed Central

    Zhou, Wu; Zhang, Lijuan; Xie, Yaoqin; Liang, Changhong

    2014-01-01

    Image pair is often aligned initially based on a rigid or affine transformation before a deformable registration method is applied in medical image registration. Inappropriate initial registration may compromise the registration speed or impede the convergence of the optimization algorithm. In this work, a novel technique was proposed for prealignment in both monomodality and multimodality image registration based on statistical correlation of gradient information. A simple and robust algorithm was proposed to determine the rotational differences between two images based on orientation histogram matching accumulated from local orientation of each pixel without any feature extraction. Experimental results showed that it was effective to acquire the orientation angle between two unregistered images with advantages over the existed method based on edge-map in multimodalities. Applying the orientation detection into the registration of CT/MR, T1/T2 MRI, and monomadality images with respect to rigid and nonrigid deformation improved the chances of finding the global optimization of the registration and reduced the search space of optimization. PMID:25162024

  13. Brain CT and MRI: differential diagnosis of imaging findings.

    PubMed

    Masdeu, Joseph C; Gadhia, Rajan; Faridar, Alireza

    2016-01-01

    Following a traditional approach, in Chapters 5 and 14-29 in the previous volume, diverse brain diseases are listed and their imaging findings described in detail. In this chapter the approach is from the imaging finding to the disease: for instance, what list of diseases can give rise to a contrast-enhancing mass in the cerebellopontine angle? Imaging findings that are reviewed in succession include the location of the lesion, its multiplicity and symmetry, its volume, ranging from atrophy to mass effect, its homogeneity, its density, measurable by computed tomography (CT), its appearance on T1, T2, and diffusion magnetic resonance imaging (MRI), and, finally, its characteristics after the infusion of intravenous contrast. A differential diagnosis for each finding is provided. While the approach adopted in this chapter is unconventional, we hope that it will be most helpful to anyone reading images. Furthermore, it could serve as the basis to create or complete image databases to guide in the interpretation of brain CT and MRI. PMID:27430457

  14. Medical imaging with a microwave tomographic scanner.

    PubMed

    Jofre, L; Hawley, M S; Broquetas, A; de los Reyes, E; Ferrando, M; Elias-Fusté, A R

    1990-03-01

    A microwave tomographic scanner for biomedical applications is presented. The scanner consists of a 64 element circular array with a useful diameter of 20 cm. Electronically scanning the transmitting and receiving antennas allows multiview measurements with no mechanical movement. Imaging parameters are appropriate for medical use: a spatial resolution of 7 mm and a contrast resolution of 1% for a measurement time of 3 s. Measurements on tissue-simulating phantoms and volunteers, together with numerical simulations, are presented to assess the system for absolute imaging of tissue distribution and for differential imaging of physiological, pathological, and induced changes in tissues. PMID:2329003

  15. A stationary wavelet transform based approach to registration of planning CT and setup cone beam-CT images in radiotherapy.

    PubMed

    Deng, Jun-Min; Yue, Hai-Zhen; Zhuo, Zhi-Zheng; Yan, Hua-Gang; Liu, Di; Li, Hai-Yun

    2014-05-01

    Image registration between planning CT images and cone beam-CT (CBCT) images is one of the key technologies of image guided radiotherapy (IGRT). Current image registration methods fall roughly into two categories: geometric features-based and image grayscale-based. Mutual information (MI) based registration, which belongs to the latter category, has been widely applied to multi-modal and mono-modal image registration. However, the standard mutual information method only focuses on the image intensity information and overlooks spatial information, leading to the instability of intensity interpolation. Due to its use of positional information, wavelet transform has been applied to image registration recently. In this study, we proposed an approach to setup CT and cone beam-CT (CBCT) image registration in radiotherapy based on the combination of mutual information (MI) and stationary wavelet transform (SWT). Firstly, SWT was applied to generate gradient images and low frequency components produced in various levels of image decomposition were eliminated. Then inverse SWT was performed on the remaining frequency components. Lastly, the rigid registration of gradient images and original images was implemented using a weighting function with the normalized mutual information (NMI) being the similarity measure, which compensates for the lack of spatial information in mutual information based image registration. Our experiment results showed that the proposed method was highly accurate and robust, and indicated a significant clinical potential in improving the accuracy of target localization in image guided radiotherapy (IGRT). PMID:24729043

  16. 21 CFR 892.2040 - Medical image hardcopy device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Medical image hardcopy device. 892.2040 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2040 Medical image hardcopy device. (a) Identification. A medical image hardcopy device is a device that produces a visible printed record of a...

  17. 21 CFR 892.2010 - Medical image storage device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Medical image storage device. 892.2010 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2010 Medical image storage device. (a) Identification. A medical image storage device is a device that provides electronic storage and...

  18. 21 CFR 892.2040 - Medical image hardcopy device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical image hardcopy device. 892.2040 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2040 Medical image hardcopy device. (a) Identification. A medical image hardcopy device is a device that produces a visible printed record of a...

  19. 21 CFR 892.2010 - Medical image storage device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Medical image storage device. 892.2010 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2010 Medical image storage device. (a) Identification. A medical image storage device is a device that provides electronic storage and...

  20. 21 CFR 892.2020 - Medical image communications device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Medical image communications device. 892.2020... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2020 Medical image communications device. (a) Identification. A medical image communications device provides electronic transfer of...

  1. 21 CFR 892.2010 - Medical image storage device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Medical image storage device. 892.2010 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2010 Medical image storage device. (a) Identification. A medical image storage device is a device that provides electronic storage and...

  2. 21 CFR 892.2010 - Medical image storage device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Medical image storage device. 892.2010 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2010 Medical image storage device. (a) Identification. A medical image storage device is a device that provides electronic storage and...

  3. 21 CFR 892.2040 - Medical image hardcopy device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Medical image hardcopy device. 892.2040 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2040 Medical image hardcopy device. (a) Identification. A medical image hardcopy device is a device that produces a visible printed record of a...

  4. 21 CFR 892.2040 - Medical image hardcopy device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Medical image hardcopy device. 892.2040 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2040 Medical image hardcopy device. (a) Identification. A medical image hardcopy device is a device that produces a visible printed record of a...

  5. 21 CFR 892.2020 - Medical image communications device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Medical image communications device. 892.2020... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2020 Medical image communications device. (a) Identification. A medical image communications device provides electronic transfer of...

  6. 21 CFR 892.2020 - Medical image communications device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical image communications device. 892.2020... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2020 Medical image communications device. (a) Identification. A medical image communications device provides electronic transfer of...

  7. 21 CFR 892.2040 - Medical image hardcopy device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Medical image hardcopy device. 892.2040 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2040 Medical image hardcopy device. (a) Identification. A medical image hardcopy device is a device that produces a visible printed record of a...

  8. 21 CFR 892.2020 - Medical image communications device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Medical image communications device. 892.2020... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2020 Medical image communications device. (a) Identification. A medical image communications device provides electronic transfer of...

  9. 21 CFR 892.2020 - Medical image communications device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Medical image communications device. 892.2020... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2020 Medical image communications device. (a) Identification. A medical image communications device provides electronic transfer of...

  10. 21 CFR 892.2010 - Medical image storage device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical image storage device. 892.2010 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2010 Medical image storage device. (a) Identification. A medical image storage device is a device that provides electronic storage and...

  11. Brain Imaging Using Mobile CT: Current Status and Future Prospects.

    PubMed

    John, Seby; Stock, Sarah; Cerejo, Russell; Uchino, Ken; Winners, Stacey; Russman, Andrew; Masaryk, Thomas; Rasmussen, Peter; Hussain, Muhammad S

    2016-01-01

    Computed tomography (CT) is an invaluable tool in the diagnosis of many clinical conditions. Several advancements in biomedical engineering have achieved increase in speed, improvements in low-contrast detectability and image quality, and lower radiation. Portable or mobile CT constituted one such important advancement. It is especially useful in evaluating critically ill, intensive care unit patients by scanning them at bedside. A paradigm shift in utilization of mobile CT was its installation in ambulances for the management of acute stroke. Given the time sensitive nature of acute ischemic stroke, Mobile stroke units (MSU) were developed in Germany consisting of an ambulance equipped with a CT scanner, point of care laboratory system, along with teleradiological support. In a radical reconfiguration of stroke care, the MSU would bring the CT scanner to the stroke patient, without waiting for the patient at the emergency room. Two separate MSU projects in Saarland and Berlin demonstrated the safety and feasibility of this concept for prehospital stroke care, showing increased rate of intravenous thrombolysis and significant reduction in time to treatment compared to conventional care. MSU also improved the triage of patients to appropriate and specialized hospitals. Although multiple issues remain yet unanswered with the MSU concept including clinical outcome and cost-effectiveness, the MSU venture is visionary and enables delivery of life-saving and enhancing treatment for ischemic and hemorrhagic stroke. In this review, we discuss the development of mobile CT and its applications, with specific focus on its use in MSUs along with our institution's MSU experience. PMID:26593629

  12. Rodent Brain Imaging with X-ray CT

    NASA Astrophysics Data System (ADS)

    Seo, Youngho; Hashimoto, Tomoki; Nuki, Yoshitsugu; Hasegawa, Bruce; Franc, Benjamin

    2007-03-01

    High resolution compact computed tomography (CT) systems have become increasingly important for examining morphology in small animal models of human biology and disease. However, functional measurements of blood flow and tissue perfusion are more challenging due to limited temporal resolution and need for x-ray absorptive contrast media. We therefore have developed methodologies which use x-ray CT for imaging hemorrhagic stroke in the brain of the intact rat. The head of the anesthetized rat was secured in an immobilization device, followed by in vivo imaging with a dedicated small animal CT scanner (X-O, Gamma Medica-Ideas, Northridge, CA). Imaging was performed without iodine contrast to visualize a very small volume (less than 0.1 ml) of arterial blood in a rat model of intracranial hemorrhage, and with iodine contrast (iopromide, 300 mgI/ml) to visualize carotid and cerebral arteries in order to study aneurysms and other vascular formations that may precede or indicate intracranial hemorrhage.

  13. Design patterns in medical imaging information systems

    NASA Astrophysics Data System (ADS)

    Hoo, Kent S., Jr.; Wong, Stephen T. C.; Laxer, Kenneth D.; Knowlton, Robert C.; Ching, Wan

    2000-05-01

    The purpose of this paper is to introduce a new and important conceptual framework of software design for the medical imaging community using design patterns. Use cases are created to summarize operational scenarios of clinicians using the system to complete certain tasks such as image segmentation. During design the Unified Modeling Language is used to translate the use cases into modeling diagrams that describe how the system functions. Next, design patterns are applied to build models that describe how software components interoperate to deliver that functionality. The software components are implemented using the Java language, CORBA architecture, and other web technologies. The biomedical image information system is used in epilepsy neurosurgical planning and diagnosis. This article proposes the use of proven software design models for solving medical imaging informatics design problems. Design patterns provide an excellent vehicle to leverage design solutions that have worked in the past to solve the problems we face in building user-friendly, reliable, and efficient information systems. This work introduces this new technology for building increasing complex medical image information systems. The rigorous application of software design techniques is essential in building information systems that are easy to use, rich in functionality, maintainable, reliable, and updatable.

  14. Estimating fractal dimension of medical images

    NASA Astrophysics Data System (ADS)

    Penn, Alan I.; Loew, Murray H.

    1996-04-01

    Box counting (BC) is widely used to estimate the fractal dimension (fd) of medical images on the basis of a finite set of pixel data. The fd is then used as a feature to discriminate between healthy and unhealthy conditions. We show that BC is ineffective when used on small data sets and give examples of published studies in which researchers have obtained contradictory and flawed results by using BC to estimate the fd of data-limited medical images. We present a new method for estimating fd of data-limited medical images. In the new method, fractal interpolation functions (FIFs) are used to generate self-affine models of the underlying image; each model, upon discretization, approximates the original data points. The fd of each FIF is analytically evaluated. The mean of the fds of the FIFs is the estimate of the fd of the original data. The standard deviation of the fds of the FIFs is a confidence measure of the estimate. The goodness-of-fit of the discretized models to the original data is a measure of self-affinity of the original data. In a test case, the new method generated a stable estimate of fd of a rib edge in a standard chest x-ray; box counting failed to generate a meaningful estimate of the same image.

  15. Robust retrieval from compressed medical image archives

    NASA Astrophysics Data System (ADS)

    Sidorov, Denis N.; Lerallut, Jean F.; Cocquerez, Jean-Pierre; Azpiroz, Joaquin

    2005-04-01

    Paper addresses the computational aspects of extracting important features directly from compressed images for the purpose of aiding biomedical image retrieval based on content. The proposed method for treatment of compressed medical archives follows the JPEG compression standard and exploits algorithm based on spacial analysis of the image cosine spectrum coefficients amplitude and location. The experiments on modality-specific archive of osteoarticular images show robustness of the method based on measured spectral spatial statistics. The features, which were based on the cosine spectrum coefficients' values, could satisfy different types of queries' modalities (MRI, US, etc), which emphasized texture and edge properties. In particular, it has been shown that there is wealth of information in the AC coefficients of the DCT transform, which can be utilized to support fast content-based image retrieval. The computational cost of proposed signature generation algorithm is low. Influence of conventional and the state-of-the-art compression techniques based on cosine and wavelet integral transforms on the performance of content-based medical image retrieval has been also studied. We found no significant differences in retrieval efficiencies for non-compressed and JPEG2000-compressed images even at the lowest bit rate tested.

  16. [Intraoperative CT imaging system using a mobile CT scanner gantry mounted on floor-embedded rails for neurosurgery].

    PubMed

    Kabuto, M; Kubota, T; Kobayashi, H; Handa, Y; Sato, K; Ishii, H; Takeuchi, H; Uno, H; Arishima, H; Ido, K; Ueda, Y; Adachi, M; Ishida, M; Hasegawa, Y; Yanagimoto, M; Goto, Y

    1998-11-01

    Many neurosurgeons prefer to use intraoperative computed tomographic (CT) scanning, when possible, to check whether there is residual lesion or unexpected bleeding. We report a practical intraoperative CT imaging system using a high-speed CT scanner installed in the operating room along with a digitally controlled neurosurgical operating table. We designed a rail-track system to mobilize the CT gantry. The gantry is fixed onto a motorized carrier that can be moved smoothly on a rail-track embedded in the floor and with a maximum reach of 2.85 m from the room's wall to the operating table. The longitudinal motion of the operating table is easily adjusted by a foot switch from manual control to automatic control directly from the CT scanner's computer like an ordinary CT scanner bed in increments of 2, 5 or 10 mm during CT scanning. Either a carbon-made radiolucent head frame or carbon-made head plate is used as a headrest. Using this CT scanner system, pre- and intraoperative CT scannings were performed on 46 patients with brain tumors, cervical lesions or other intracranial lesions. We could operate on the patient with enough working space between the mobile CT gantry and the operating table for microneurosurgery. We could obtain intraoperative CT imaging of a patient on the operating table while the surgical wound remained open, the surgical drapes kept in place, and the surgical position unchanged, saving time in intraoperative CT scanning and preparation for further surgery when needed. This intraoperative CT imaging system installed in the operating room should be useful for neurosurgery. PMID:9866126

  17. Neural networks: Application to medical imaging

    NASA Technical Reports Server (NTRS)

    Clarke, Laurence P.

    1994-01-01

    The research mission is the development of computer assisted diagnostic (CAD) methods for improved diagnosis of medical images including digital x-ray sensors and tomographic imaging modalities. The CAD algorithms include advanced methods for adaptive nonlinear filters for image noise suppression, hybrid wavelet methods for feature segmentation and enhancement, and high convergence neural networks for feature detection and VLSI implementation of neural networks for real time analysis. Other missions include (1) implementation of CAD methods on hospital based picture archiving computer systems (PACS) and information networks for central and remote diagnosis and (2) collaboration with defense and medical industry, NASA, and federal laboratories in the area of dual use technology conversion from defense or aerospace to medicine.

  18. A patient-centric distribution architecture for medical image sharing.

    PubMed

    Constantinescu, Liviu; Kim, Jinman; Kumar, Ashnil; Haraguchi, Daiki; Wen, Lingfeng; Feng, Dagan

    2013-01-01

    Over the past decade, rapid development of imaging technologies has resulted in the introduction of improved imaging devices, such as multi-modality scanners that produce combined positron emission tomography-computed tomography (PET-CT) images. The adoption of picture archiving and communication systems (PACS) in hospitals have dramatically improved the ability to digitally share medical image studies via portable storage, mobile devices and the Internet. This has in turn led to increased productivity, greater flexibility, and improved communication between hospital staff, referring physicians, and outpatients. However, many of these sharing and viewing capabilities are limited to proprietary vendor-specific applications. Furthermore, there are still interoperability and deployment issues which reduce the rate of adoption of such technologies, thus leaving many stakeholders, particularly outpatients and referring physicians, with access to only traditional still images with no ability to view or interpret the data in full. In this paper, we present a distribution architecture for medical image display across numerous devices and media, which uses a preprocessor and an in-built networking framework to improve compatibility and promote greater accessibility of medical data. Our INVOLVE2 system consists of three main software modules: 1) a preprocessor, which collates and converts imaging studies into a compressed and distributable format; 2) a PACS-compatible workflow for self-managing distribution of medical data, e.g. via CD USB, network etc; 3) support for potential mobile and web-based data access. The focus of this study was on cultivating patient-centric care, by allowing outpatient users to comfortably access and interpret their own data. As such, the image viewing software included on our cross-platform CDs was designed with a simple and intuitive user-interface (UI) for use by outpatients and referring physicians. Furthermore, digital image access via

  19. Semiautomatic segmentation of liver metastases on volumetric CT images

    SciTech Connect

    Yan, Jiayong; Schwartz, Lawrence H.; Zhao, Binsheng

    2015-11-15

    Purpose: Accurate segmentation and quantification of liver metastases on CT images are critical to surgery/radiation treatment planning and therapy response assessment. To date, there are no reliable methods to perform such segmentation automatically. In this work, the authors present a method for semiautomatic delineation of liver metastases on contrast-enhanced volumetric CT images. Methods: The first step is to manually place a seed region-of-interest (ROI) in the lesion on an image. This ROI will (1) serve as an internal marker and (2) assist in automatically identifying an external marker. With these two markers, lesion contour on the image can be accurately delineated using traditional watershed transformation. Density information will then be extracted from the segmented 2D lesion and help determine the 3D connected object that is a candidate of the lesion volume. The authors have developed a robust strategy to automatically determine internal and external markers for marker-controlled watershed segmentation. By manually placing a seed region-of-interest in the lesion to be delineated on a reference image, the method can automatically determine dual threshold values to approximately separate the lesion from its surrounding structures and refine the thresholds from the segmented lesion for the accurate segmentation of the lesion volume. This method was applied to 69 liver metastases (1.1–10.3 cm in diameter) from a total of 15 patients. An independent radiologist manually delineated all lesions and the resultant lesion volumes served as the “gold standard” for validation of the method’s accuracy. Results: The algorithm received a median overlap, overestimation ratio, and underestimation ratio of 82.3%, 6.0%, and 11.5%, respectively, and a median average boundary distance of 1.2 mm. Conclusions: Preliminary results have shown that volumes of liver metastases on contrast-enhanced CT images can be accurately estimated by a semiautomatic segmentation

  20. The use of megavoltage CT (MVCT) images for dose recomputations

    NASA Astrophysics Data System (ADS)

    Langen, K. M.; Meeks, S. L.; Poole, D. O.; Wagner, T. H.; Willoughby, T. R.; Kupelian, P. A.; Ruchala, K. J.; Haimerl, J.; Olivera, G. H.

    2005-09-01

    Megavoltage CT (MVCT) images of patients are acquired daily on a helical tomotherapy unit (TomoTherapy, Inc., Madison, WI). While these images are used primarily for patient alignment, they can also be used to recalculate the treatment plan for the patient anatomy of the day. The use of MVCT images for dose computations requires a reliable CT number to electron density calibration curve. In this work, we tested the stability of the MVCT numbers by determining the variation of this calibration with spatial arrangement of the phantom, time and MVCT acquisition parameters. The two calibration curves that represent the largest variations were applied to six clinical MVCT images for recalculations to test for dosimetric uncertainties. Among the six cases tested, the largest difference in any of the dosimetric endpoints was 3.1% but more typically the dosimetric endpoints varied by less than 2%. Using an average CT to electron density calibration and a thorax phantom, a series of end-to-end tests were run. Using a rigid phantom, recalculated dose volume histograms (DVHs) were compared with plan DVHs. Using a deformed phantom, recalculated point dose variations were compared with measurements. The MVCT field of view is limited and the image space outside this field of view can be filled in with information from the planning kVCT. This merging technique was tested for a rigid phantom. Finally, the influence of the MVCT slice thickness on the dose recalculation was investigated. The dosimetric differences observed in all phantom tests were within the range of dosimetric uncertainties observed due to variations in the calibration curve. The use of MVCT images allows the assessment of daily dose distributions with an accuracy that is similar to that of the initial kVCT dose calculation.

  1. Multi-technique hybrid imaging in PET/CT and PET/MR: what does the future hold?

    PubMed

    de Galiza Barbosa, F; Delso, G; Ter Voert, E E G W; Huellner, M W; Herrmann, K; Veit-Haibach, P

    2016-07-01

    Integrated positron-emission tomography and computed tomography (PET/CT) is one of the most important imaging techniques to have emerged in oncological practice in the last decade. Hybrid imaging, in general, remains a rapidly growing field, not only in developing countries, but also in western industrialised healthcare systems. A great deal of technological development and research is focused on improving hybrid imaging technology further and introducing new techniques, e.g., integrated PET and magnetic resonance imaging (PET/MRI). Additionally, there are several new PET tracers on the horizon, which have the potential to broaden clinical applications in hybrid imaging for diagnosis as well as therapy. This article aims to highlight some of the major technical and clinical advances that are currently taking place in PET/CT and PET/MRI that will potentially maintain the position of hybrid techniques at the forefront of medical imaging technologies. PMID:27108800

  2. Ground truth and CT image model simulation for pathophysiological human airway system

    NASA Astrophysics Data System (ADS)

    Ortner, Margarete; Fetita, Catalin; Brillet, Pierre-Yves; Pr"teux, Françoise; Grenier, Philippe

    2010-02-01

    Recurrent problem in medical image segmentation and analysis, establishing a ground truth for assessment purposes is often difficult. Facing this problem, the scientific community orients its efforts towards the development of objective methods for evaluation, namely by building up or simulating the missing ground truth for analysis. This paper focuses on the case of human pulmonary airways and develops a method 1) to simulate the ground truth for different pathophysiological configurations of the bronchial tree as a mesh model, and 2) to generate synthetic 3D CT images of airways associated with the simulated ground truth. The airway model is here built up based on the information provided by a medial axis (describing bronchus shape, subdivision geometry and local radii), which is computed from real CT data to ensure realism and matching with a patient-specific morphology. The model parameters can be further on adjusted to simulate various pathophysiological conditions of the same patient (longitudinal studies). Based on the airway mesh model, a 3D image model is synthesized by simulating the CT acquisition process. The image realism is achieved by including textural features of the surrounding pulmonary tissue which are obtained by segmentation from the same original CT data providing the airway axis. By varying the scanning simulation parameters, several 3D image models can be generated for the same airway mesh ground truth. Simulation results for physiological and pathological configurations are presented and discussed, illustrating the interest of such a modeling process for designing computer-aided diagnosis systems or for assessing their sensitivity, mainly for follow-up studies in asthma and COPD.

  3. Medical image registration using sparse coding of image patches.

    PubMed

    Afzali, Maryam; Ghaffari, Aboozar; Fatemizadeh, Emad; Soltanian-Zadeh, Hamid

    2016-06-01

    Image registration is a basic task in medical image processing applications like group analysis and atlas construction. Similarity measure is a critical ingredient of image registration. Intensity distortion of medical images is not considered in most previous similarity measures. Therefore, in the presence of bias field distortions, they do not generate an acceptable registration. In this paper, we propose a sparse based similarity measure for mono-modal images that considers non-stationary intensity and spatially-varying distortions. The main idea behind this measure is that the aligned image is constructed by an analysis dictionary trained using the image patches. For this purpose, we use "Analysis K-SVD" to train the dictionary and find the sparse coefficients. We utilize image patches to construct the analysis dictionary and then we employ the proposed sparse similarity measure to find a non-rigid transformation using free form deformation (FFD). Experimental results show that the proposed approach is able to robustly register 2D and 3D images in both simulated and real cases. The proposed method outperforms other state-of-the-art similarity measures and decreases the transformation error compared to the previous methods. Even in the presence of bias field distortion, the proposed method aligns images without any preprocessing. PMID:27085311

  4. CT and MR imaging of odontoid abnormalities: A pictorial review

    PubMed Central

    Jain, Nishchint; Verma, Ritu; Garga, Umesh C; Baruah, Barinder P; Jain, Sachin K; Bhaskar, Surya N

    2016-01-01

    Odontoid process is the central pillar of the craniovertebral junction. Imaging of this small structure continues to be a challenge for the radiologists due to complex bony and ligamentous anatomy. A wide range of developmental and acquired abnormalities of odontoid have been identified. Their accurate radiologic evaluation is important as different lesions have markedly different clinical course, patient management, and prognosis. This article seeks to provide knowledge for interpreting appearances of odontoid on computed tomography (CT) and magnetic resonance imaging (MRI) with respect to various disease processes, along with providing a quick review of the embryology and relevant anatomy. PMID:27081234

  5. CT and MR imaging of odontoid abnormalities: A pictorial review.

    PubMed

    Jain, Nishchint; Verma, Ritu; Garga, Umesh C; Baruah, Barinder P; Jain, Sachin K; Bhaskar, Surya N

    2016-01-01

    Odontoid process is the central pillar of the craniovertebral junction. Imaging of this small structure continues to be a challenge for the radiologists due to complex bony and ligamentous anatomy. A wide range of developmental and acquired abnormalities of odontoid have been identified. Their accurate radiologic evaluation is important as different lesions have markedly different clinical course, patient management, and prognosis. This article seeks to provide knowledge for interpreting appearances of odontoid on computed tomography (CT) and magnetic resonance imaging (MRI) with respect to various disease processes, along with providing a quick review of the embryology and relevant anatomy. PMID:27081234

  6. Pancreas tumor model in rabbit imaged by perfusion CT scans

    NASA Astrophysics Data System (ADS)

    Gunn, Jason; Tichauer, Kenneth; Moodie, Karen; Kane, Susan; Hoopes, Jack; Stewart, Errol E.; Hadway, Jennifer; Lee, Ting-Yim; Pereira, Stephen P.; Pogue, Brian W.

    2013-03-01

    The goal of this work was to develop and validate a pancreas tumor animal model to investigate the relationship between photodynamic therapy (PDT) effectiveness and photosensitizer drug delivery. More specifically, this work lays the foundation for investigating the utility of dynamic contrast enhanced blood perfusion imaging to be used to inform subsequent PDT. A VX2 carcinoma rabbit cell line was grown in the tail of the pancreas of three New Zealand White rabbits and approximately 3-4 weeks after implantation the rabbits were imaged on a CT scanner using a contrast enhanced perfusion protocol, providing parametric maps of blood flow, blood volume, mean transit time, and vascular permeability surface area product.

  7. Imaging of Scrub Typhus by PET/CT.

    PubMed

    Lv, Jing; Liu, Shuai; Pan, Yu; Ju, Huijun; Zhang, Yifan

    2015-10-01

    A 19-year-old man had an unexplained fever, dizziness, headache, fatigue, and pain in the scrotum. An FDG PET/CT imaging was acquired to assess fever of unknown origin. The images showed multiple foci of increased FDG activity in the enlarged lymph nodes in the body. In addition, mildly increased activity in the enlarged spleen and lung bases was also noted. The patient was eventually diagnosed with scrub typhus based on positive results of the Weil-Felix agglutination test, eschar in the scrotum, and effective therapy. PMID:26252322

  8. Discriminative boundary detection for model-based heart segmentation in CT images

    NASA Astrophysics Data System (ADS)

    Peters, Jochen; Ecabert, Olivier; Schramm, Hauke; Weese, Jürgen

    2007-03-01

    Segmentation of organs in medical images can be successfully performed with deformable models. Most approaches combine a boundary detection step with some smoothness or shape constraint. An objective function for the model deformation is thus established from two terms: the first one attracts the surface model to the detected boundaries while the second one keeps the surface smooth or close to expected shapes. In this work, we assign locally varying boundary detection functions to all parts of the surface model. These functions combine an edge detector with local image analysis in order to accept or reject possible edge candidates. The goal is to optimize the discrimination between the wanted and misleading boundaries. We present a method to automatically learn from a representative set of 3D training images which features are optimal at each position of the surface model. The basic idea is to simulate the boundary detection for the given 3D images and to select those features that minimize the distance between the detected position and the desired object boundary. The approach is experimentally evaluated for the complex task of full-heart segmentation in CT images. A cyclic cross-evaluation on 25 cardiac CT images shows that the optimized feature training and selection enables robust, fully automatic heart segmentation with a mean error well below 1 mm. Comparing this approach to simpler training schemes that use the same basic formalism to accept or reject edges shows the importance of the discriminative optimization.

  9. Camera motion tracking of real bronchoscope using epipolar geometry analysis and CT-derived bronchoscopic images

    NASA Astrophysics Data System (ADS)

    Deguchi, Daisuke; Mori, Kensaku; Hasegawa, Jun-ichi; Toriwaki, Jun-ichiro; Takabatake, Hirotsugu; Natori, Hiroshi

    2002-04-01

    This paper describes a method to track camera motion of a real endoscope by using epipolar geometry analysis and CT derived virtual endoscopic images. A navigation system for a flexible endoscope guides medical doctors by providing navigation information during endoscope examinations. This paper tries to estimate the motion from an endoscopic video image based on epipolar geometry analysis and image registration between virtual endoscopic (VE) and real endoscopic (RE) images. The method consists of three parts: (a) direct estimation of camera motion by using epipolar geometry analysis, (b) precise estimation by using image registration, and (c) detection of bubble frames for avoiding miss-registration. First we calculate optical flow patterns from two consecutive frames. The camera motion is computed by substituting the obtained flows into the epipolar equations. Then we find the observation parameter of a virtual endoscopy system that generates the most similar endoscopic view to the current RE frame. We execute these processes for all frames of RE videos except for frames where bubbles appear. We applied the proposed method to RE videos of three patients who have CT images. The experimental results show the method can track camera motion for over 500 frames continuously in the best case.

  10. Image quality assessment of three cone beam CT machines using the SEDENTEXCT CT phantom

    PubMed Central

    Bamba, J; Araki, K; Endo, A; Okano, T

    2013-01-01

    Objectives: The SEDENTEXCT Project proposed quality assurance (QA) methods and introduced a QA image quality phantom. A new prototype was recently introduced that may be improved according to previous reports. The purpose of this study is to evaluate image quality in various protocols of three cone beam CT (CBCT) machines using the proposed QA phantom. Methods: Using three CBCT machines, nine image quality parameters, including image homogeneity (noise), uniformity, geometrical distortion, pixel intensity value, contrast resolution, spatial resolution [line pair (LP) chart, point spread function (PSF) and modulation transfer function (MTF)] and metal artefacts, were evaluated using a QA phantom proposed by SEDENTEXCT. Exposure parameters, slice thickness and field of view position changed variously, and the number of total protocols was 22. Results: Many protocols showed a uniform gray value distribution except in the minimum slice thickness image acquired using 3D Accuitomo 80 (Morita, Kyoto, Japan) and Veraviewepocs 3Df (Morita). Noise levels differed among the protocols. There was no geometric distortion, and the pixel intensity values were correlated with the CT value. Low contrast resolution differed among the protocols, but high contrast resolution performed well in all. Many protocols showed that the maximum line pair was larger than 1 LP mm−1 but smaller than 3 LP mm−1. PSF and MTF did not correlate well with the pixel size. The measured metal artefact areas varied for each device. Conclusions: We studied the image quality of three CBCT machines using the SEDENTEXCT phantom. Image quality varied with exposure protocols and machines. PMID:23956235

  11. Compact CT/SPECT Small-Animal Imaging System

    PubMed Central

    Kastis, George A.; Furenlid, Lars R.; Wilson, Donald W.; Peterson, Todd E.; Barber, H. Bradford; Barrett, Harrison H.

    2015-01-01

    We have developed a dual-modality CT/SPECT imaging system for small-animal imaging applications. The X-ray system comprises a commercially available micro-focus X-ray tube and a CCD-based X-ray camera. X-ray transmission measurements are performed based on cone-beam geometry. Individual projections are acquired by rotating the animal about a vertical axis in front of the CCD detector. A high-resolution CT image is obtained after reconstruction using an ordered subsets-expectation maximization (OS-EM) reconstruction algorithm. The SPECT system utilizes a compact semiconductor camera module previously developed in our group. The module is mounted perpendicular to the X-ray tube/CCD combination. It consists of a 64×64 pixellated CdZnTe detector and a parallel-hole tungsten collimator. The field of view is 1 square inch. Planar projections for SPECT reconstruction are obtained by rotating the animal in front of the detector. Gamma-ray and X-ray images are presented of phantoms and mice. Procedures for merging the anatomical and functional images are discussed. PMID:26538684

  12. 3D nonrigid medical image registration using a new information theoretic measure

    NASA Astrophysics Data System (ADS)

    Li, Bicao; Yang, Guanyu; Coatrieux, Jean Louis; Li, Baosheng; Shu, Huazhong

    2015-11-01

    This work presents a novel method for the nonrigid registration of medical images based on the Arimoto entropy, a generalization of the Shannon entropy. The proposed method employed the Jensen-Arimoto divergence measure as a similarity metric to measure the statistical dependence between medical images. Free-form deformations were adopted as the transformation model and the Parzen window estimation was applied to compute the probability distributions. A penalty term is incorporated into the objective function to smooth the nonrigid transformation. The goal of registration is to optimize an objective function consisting of a dissimilarity term and a penalty term, which would be minimal when two deformed images are perfectly aligned using the limited memory BFGS optimization method, and thus to get the optimal geometric transformation. To validate the performance of the proposed method, experiments on both simulated 3D brain MR images and real 3D thoracic CT data sets were designed and performed on the open source elastix package. For the simulated experiments, the registration errors of 3D brain MR images with various magnitudes of known deformations and different levels of noise were measured. For the real data tests, four data sets of 4D thoracic CT from four patients were selected to assess the registration performance of the method, including ten 3D CT images for each 4D CT data covering an entire respiration cycle. These results were compared with the normalized cross correlation and the mutual information methods and show a slight but true improvement in registration accuracy.

  13. Feasibility and Initial Performance of Simultaneous SPECT-CT Imaging Using a Commercial Multi-Modality Preclinical Imaging System

    PubMed Central

    Osborne, Dustin R.; Austin, Derek W.

    2015-01-01

    Multi-modality imaging provides coregistered PET-CT and SPECT-CT images; however such multi-modality workflows usually consist of sequential scans from the individual imaging components for each modality. This typical workflow may result in long scan times limiting throughput of the imaging system. Conversely, acquiring multi-modality data simultaneously may improve correlation and registration of images, improve temporal alignment of the acquired data, increase imaging throughput, and benefit the scanned subject by minimizing time under anesthetic. In this work, we demonstrate the feasibility and procedure for modifying a commercially available preclinical SPECT-CT platform to enable simultaneous SPECT-CT acquisition. We also evaluate the performance of simultaneous SPECT-CT tomographic imaging with this modified system. Performance was accessed using a 57Co source and image quality was evaluated with 99mTc phantoms in a series of simultaneous SPECT-CT scans. PMID:26146568

  14. Automatic scale selection for medical image segmentation

    NASA Astrophysics Data System (ADS)

    Bayram, Ersin; Wyatt, Christopher L.; Ge, Yaorong

    2001-07-01

    The scale of interesting structures in medical images is space variant because of partial volume effects, spatial dependence of resolution in many imaging modalities, and differences in tissue properties. Existing segmentation methods either apply a single scale to the entire image or try fine-to-coarse/coarse-to-fine tracking of structures over multiple scales. While single scale approaches fail to fully recover the perceptually important structures, multi-scale methods have problems in providing reliable means to select proper scales and integrating information over multiple scales. A recent approach proposed by Elder and Zucker addresses the scale selection problem by computing a minimal reliable scale for each image pixel. The basic premise of this approach is that, while the scale of structures within an image vary spatially, the imaging system is fixed. Hence, sensor noise statistics can be calculated. Based on a model of edges to be detected, and operators to be used for detection, one can locally compute a unique minimal reliable scale at which the likelihood of error due to sensor noise is less than or equal to a predetermined threshold. In this paper, we improve the segmentation method based on the minimal reliable scale selection and evaluate its effectiveness with both simulated and actual medical data.

  15. CT imaging signs of surgically proven bowel trauma.

    PubMed

    LeBedis, Christina A; Anderson, Stephan W; Bates, David D B; Khalil, Ramy; Matherly, David; Wing, Heidi; Burke, Peter A; Soto, Jorge A

    2016-06-01

    The objective of this study was to determine the incidence and interobserver agreement of individual CT findings as well as the bowel injury prediction score (BIPS) in surgically proven bowel injury after blunt abdominal trauma. This HIPAA-compliant retrospective study was IRB approved and consent was waived. All patients 14 years or older who sustained surgically proven bowel injury after blunt abdominal trauma between 1/1/2004 and 6/30/2015 were included. Admission trauma MDCT scans were independently interpreted by two abdominal fellowship-trained radiologists who recorded the following CT findings: intraperitoneal fluid, mesenteric hematoma/fat stranding, bowel wall thickening/hematoma, active intravenous contrast extravasation, free intraperitoneal air, bowel wall discontinuity, and focal bowel hypoenhancement. Subsequently, the electronic medical records of the included patients, admission abdominal physical exam results, admission white blood cell count, and findings at exploratory laparotomy of the included patients were recorded. Thirty-three patients met the inclusion criteria. The incidence and interobserver agreement of the CT findings were as follows: intraperitoneal fluid 93.9 %, kappa = 0.784 (good); mesenteric hematoma/fat stranding 84.8 %, kappa = 0.718 (good); bowel wall thickening/hematoma 42.4 %, kappa = 0.491 (moderate); active IV contrast extravasation 36.3 %, kappa = 1.00 (perfect); free intraperitoneal air 21.2 %, kappa = 0.904 (very good), bowel wall discontinuity 6.1 %, kappa = 1.00 (perfect); and focal bowel hypoenhancement 6.1 %, kappa = 0.468 (moderate). An absence of the specified CT findings was encountered in 9.1 % with surgically proven bowel injuries (kappa = 1.00, perfect). In our study, 9/16 patients or 56.3 % had a bowel injury prediction score (BIPS) of 2 or more as defined by McNutt et al. (J Trauma Acute Care Surg 78(1):105-111, 2014). The presence of intraperitoneal fluid and

  16. Improving image accuracy of region-of-interest in cone-beam CT using prior image.

    PubMed

    Lee, Jiseoc; Kim, Jin Sung; Cho, Seungryong

    2014-01-01

    In diagnostic follow-ups of diseases, such as calcium scoring in kidney or fat content assessment in liver using repeated CT scans, quantitatively accurate and consistent CT values are desirable at a low cost of radiation dose to the patient. Region of-interest (ROI) imaging technique is considered a reasonable dose reduction method in CT scans for its shielding geometry outside the ROI. However, image artifacts in the reconstructed images caused by missing data outside the ROI may degrade overall image quality and, more importantly, can decrease image accuracy of the ROI substantially. In this study, we propose a method to increase image accuracy of the ROI and to reduce imaging radiation dose via utilizing the outside ROI data from prior scans in the repeated CT applications. We performed both numerical and experimental studies to validate our proposed method. In a numerical study, we used an XCAT phantom with its liver and stomach changing their sizes from one scan to another. Image accuracy of the liver has been improved as the error decreased from 44.4 HU to -0.1 HU by the proposed method, compared to an existing method of data extrapolation to compensate for the missing data outside the ROI. Repeated cone-beam CT (CBCT) images of a patient who went through daily CBCT scans for radiation therapy were also used to demonstrate the performance of the proposed method experimentally. The results showed improved image accuracy inside the ROI. The magnitude of error decreased from -73.2 HU to 18 HU, and effectively reduced image artifacts throughout the entire image. PMID:24710451

  17. Imaging performance in differential phase contrast CT compared with the conventional CT-noise equivalent quanta NEQ(k)

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Yang, Yi; Tang, Shaojie

    2012-03-01

    The grating-based x-ray differential phase contrast (DPC) CT is emerging as a new technology with the potential for extensive preclinical and clinical applications. In general, the performance of an imaging system is jointly determined by its signal property (modulation transfer function-MTF(k)) and noise property (noise power spectrum-NPS(k)), which is characterized by its spectrum of noise equivalent quanta. As reported by us previously, owing to an adoption of the Hilbert filtering for image reconstruction in the fashion of filtered backprojection (FBP), the noise property of DPC-CT characterized by its NPS(k) differs drastically from that of the conventional attenuation-based CT (1/|k| trait vs. |k| trait). In this work, via system analysis, modeling and simulated phantom study, we initially investigate the signal property of DPC-CT characterized by its MTF(k) and compare it with that of the conventional CT. In addition, we investigate the DPC-CT's spectrum of noise equivalent quanta NEQ(k) - the most important figure of merit (FOM) in the assessment of an imaging system's performance - by taking the MTF(k) and NPS(k) jointly into account. Through such a thorough investigation into both the signal and noise properties, the imaging performance of DPC-CT and its potential over the conventional attenuation-based CT can be fully understood and appreciated.

  18. A study on quantifying COPD severity by combining pulmonary function tests and CT image analysis

    NASA Astrophysics Data System (ADS)

    Nimura, Yukitaka; Kitasaka, Takayuki; Honma, Hirotoshi; Takabatake, Hirotsugu; Mori, Masaki; Natori, Hiroshi; Mori, Kensaku

    2011-03-01

    This paper describes a novel method that can evaluate chronic obstructive pulmonary disease (COPD) severity by combining measurements of pulmonary function tests and measurements obtained from CT image analysis. There is no cure for COPD. However, with regular medical care and consistent patient compliance with treatments and lifestyle changes, the symptoms of COPD can be minimized and progression of the disease can be slowed. Therefore, many diagnosis methods based on CT image analysis have been proposed for quantifying COPD. Most of diagnosis methods for COPD extract the lesions as low-attenuation areas (LAA) by thresholding and evaluate the COPD severity by calculating the LAA in the lung (LAA%). However, COPD is usually the result of a combination of two conditions, emphysema and chronic obstructive bronchitis. Therefore, the previous methods based on only LAA% do not work well. The proposed method utilizes both of information including the measurements of pulmonary function tests and the results of the chest CT image analysis to evaluate the COPD severity. In this paper, we utilize a multi-class AdaBoost to combine both of information and classify the COPD severity into five stages automatically. The experimental results revealed that the accuracy rate of the proposed method was 88.9% (resubstitution scheme) and 64.4% (leave-one-out scheme).

  19. TH-C-18A-06: Combined CT Image Quality and Radiation Dose Monitoring Program Based On Patient Data to Assess Consistency of Clinical Imaging Across Scanner Models

    SciTech Connect

    Christianson, O; Winslow, J; Samei, E

    2014-06-15

    Purpose: One of the principal challenges of clinical imaging is to achieve an ideal balance between image quality and radiation dose across multiple CT models. The number of scanners and protocols at large medical centers necessitates an automated quality assurance program to facilitate this objective. Therefore, the goal of this work was to implement an automated CT image quality and radiation dose monitoring program based on actual patient data and to use this program to assess consistency of protocols across CT scanner models. Methods: Patient CT scans are routed to a HIPPA compliant quality assurance server. CTDI, extracted using optical character recognition, and patient size, measured from the localizers, are used to calculate SSDE. A previously validated noise measurement algorithm determines the noise in uniform areas of the image across the scanned anatomy to generate a global noise level (GNL). Using this program, 2358 abdominopelvic scans acquired on three commercial CT scanners were analyzed. Median SSDE and GNL were compared across scanner models and trends in SSDE and GNL with patient size were used to determine the impact of differing automatic exposure control (AEC) algorithms. Results: There was a significant difference in both SSDE and GNL across scanner models (9–33% and 15–35% for SSDE and GNL, respectively). Adjusting all protocols to achieve the same image noise would reduce patient dose by 27–45% depending on scanner model. Additionally, differences in AEC methodologies across vendors resulted in disparate relationships of SSDE and GNL with patient size. Conclusion: The difference in noise across scanner models indicates that protocols are not optimally matched to achieve consistent image quality. Our results indicated substantial possibility for dose reduction while achieving more consistent image appearance. Finally, the difference in AEC methodologies suggests the need for size-specific CT protocols to minimize variability in image

  20. Extended query refinement for medical image retrieval.

    PubMed

    Deserno, Thomas M; Güld, Mark O; Plodowski, Bartosz; Spitzer, Klaus; Wein, Berthold B; Schubert, Henning; Ney, Hermann; Seidl, Thomas

    2008-09-01

    The impact of image pattern recognition on accessing large databases of medical images has recently been explored, and content-based image retrieval (CBIR) in medical applications (IRMA) is researched. At the present, however, the impact of image retrieval on diagnosis is limited, and practical applications are scarce. One reason is the lack of suitable mechanisms for query refinement, in particular, the ability to (1) restore previous session states, (2) combine individual queries by Boolean operators, and (3) provide continuous-valued query refinement. This paper presents a powerful user interface for CBIR that provides all three mechanisms for extended query refinement. The various mechanisms of man-machine interaction during a retrieval session are grouped into four classes: (1) output modules, (2) parameter modules, (3) transaction modules, and (4) process modules, all of which are controlled by a detailed query logging. The query logging is linked to a relational database. Nested loops for interaction provide a maximum of flexibility within a minimum of complexity, as the entire data flow is still controlled within a single Web page. Our approach is implemented to support various modalities, orientations, and body regions using global features that model gray scale, texture, structure, and global shape characteristics. The resulting extended query refinement has a significant impact for medical CBIR applications. PMID:17497197

  1. Infective endocarditis detection through SPECT/CT images digital processing

    NASA Astrophysics Data System (ADS)

    Moreno, Albino; Valdés, Raquel; Jiménez, Luis; Vallejo, Enrique; Hernández, Salvador; Soto, Gabriel

    2014-03-01

    Infective endocarditis (IE) is a difficult-to-diagnose pathology, since its manifestation in patients is highly variable. In this work, it was proposed a semiautomatic algorithm based on SPECT images digital processing for the detection of IE using a CT images volume as a spatial reference. The heart/lung rate was calculated using the SPECT images information. There were no statistically significant differences between the heart/lung rates values of a group of patients diagnosed with IE (2.62+/-0.47) and a group of healthy or control subjects (2.84+/-0.68). However, it is necessary to increase the study sample of both the individuals diagnosed with IE and the control group subjects, as well as to improve the images quality.

  2. Non-rigid registration between 3D ultrasound and CT images of the liver based on intensity and gradient information

    NASA Astrophysics Data System (ADS)

    Lee, Duhgoon; Nam, Woo Hyun; Lee, Jae Young; Ra, Jong Beom

    2011-01-01

    In order to utilize both ultrasound (US) and computed tomography (CT) images of the liver concurrently for medical applications such as diagnosis and image-guided intervention, non-rigid registration between these two types of images is an essential step, as local deformation between US and CT images exists due to the different respiratory phases involved and due to the probe pressure that occurs in US imaging. This paper introduces a voxel-based non-rigid registration algorithm between the 3D B-mode US and CT images of the liver. In the proposed algorithm, to improve the registration accuracy, we utilize the surface information of the liver and gallbladder in addition to the information of the vessels inside the liver. For an effective correlation between US and CT images, we treat those anatomical regions separately according to their characteristics in US and CT images. Based on a novel objective function using a 3D joint histogram of the intensity and gradient information, vessel-based non-rigid registration is followed by surface-based non-rigid registration in sequence, which improves the registration accuracy. The proposed algorithm is tested for ten clinical datasets and quantitative evaluations are conducted. Experimental results show that the registration error between anatomical features of US and CT images is less than 2 mm on average, even with local deformation due to different respiratory phases and probe pressure. In addition, the lesion registration error is less than 3 mm on average with a maximum of 4.5 mm that is considered acceptable for clinical applications.

  3. Ultrasmall dopamine-coated nanogolds: preparation, characteristics, and CT imaging

    PubMed Central

    Yu, Yao; Wu, Youshen; Liu, JiaJun; Zhan, Yonghua; Wu, Daocheng

    2016-01-01

    ABSTRACT Water-dispersible ultrasmall nanogolds (WDU AuNPs) and their dopamine-coated nanogolds (WDU AuNPs@DPAs) were prepared by a reduction method with sodium borohydride as a reducing agent and a stabilised agent of 2-mercaptosuccinic acid in aqueous solution. The effects of these nanoparticles on computed tomography (CT) imaging were evaluated. The size distributions and Zeta potential of the nanoparticles were measured with a Malvern size analyser, and nanoparticle morphology was observed by transmission electron microscopy. These characteristics were confirmed by Fourier transform spectroscopy and ultraviolet/visible spectra. It was found that WDU AuNPs@DPAs were 5.4 nm in size with clear core–shell structure. The 3-(4, 5-Dimethyl-2-thiazolyl)-2, 5-diphenyltetrazolium bromide assay results showed that the WDU AuNPs and WDU AuNPs@DPAs were hypotoxic to different cells. The WDU AuNPs@DPAs showed a much longer circulation time and a larger CT attenuation coefficient than iohexol and could be excreted by the kidney and bladder. These nanoparticles showed considerable potential for future application in CT imaging. PMID:27366201

  4. Iterative image-domain decomposition for dual-energy CT

    SciTech Connect

    Niu, Tianye; Dong, Xue; Petrongolo, Michael; Zhu, Lei

    2014-04-15

    Purpose: Dual energy CT (DECT) imaging plays an important role in advanced imaging applications due to its capability of material decomposition. Direct decomposition via matrix inversion suffers from significant degradation of image signal-to-noise ratios, which reduces clinical values of DECT. Existing denoising algorithms achieve suboptimal performance since they suppress image noise either before or after the decomposition and do not fully explore the noise statistical properties of the decomposition process. In this work, the authors propose an iterative image-domain decomposition method for noise suppression in DECT, using the full variance-covariance matrix of the decomposed images. Methods: The proposed algorithm is formulated in the form of least-square estimation with smoothness regularization. Based on the design principles of a best linear unbiased estimator, the authors include the inverse of the estimated variance-covariance matrix of the decomposed images as the penalty weight in the least-square term. The regularization term enforces the image smoothness by calculating the square sum of neighboring pixel value differences. To retain the boundary sharpness of the decomposed images, the authors detect the edges in the CT images before decomposition. These edge pixels have small weights in the calculation of the regularization term. Distinct from the existing denoising algorithms applied on the images before or after decomposition, the method has an iterative process for noise suppression, with decomposition performed in each iteration. The authors implement the proposed algorithm using a standard conjugate gradient algorithm. The method performance is evaluated using an evaluation phantom (Catphan©600) and an anthropomorphic head phantom. The results are compared with those generated using direct matrix inversion with no noise suppression, a denoising method applied on the decomposed images, and an existing algorithm with similar formulation as the

  5. Simplified labeling process for medical image segmentation.

    PubMed

    Gao, Mingchen; Huang, Junzhou; Huang, Xiaolei; Zhang, Shaoting; Metaxas, Dimitris N

    2012-01-01

    Image segmentation plays a crucial role in many medical imaging applications by automatically locating the regions of interest. Typically supervised learning based segmentation methods require a large set of accurately labeled training data. However, thel labeling process is tedious, time consuming and sometimes not necessary. We propose a robust logistic regression algorithm to handle label outliers such that doctors do not need to waste time on precisely labeling images for training set. To validate its effectiveness and efficiency, we conduct carefully designed experiments on cervigram image segmentation while there exist label outliers. Experimental results show that the proposed robust logistic regression algorithms achieve superior performance compared to previous methods, which validates the benefits of the proposed algorithms. PMID:23286072

  6. MATHEMATICAL METHODS IN MEDICAL IMAGE PROCESSING

    PubMed Central

    ANGENENT, SIGURD; PICHON, ERIC; TANNENBAUM, ALLEN

    2013-01-01

    In this paper, we describe some central mathematical problems in medical imaging. The subject has been undergoing rapid changes driven by better hardware and software. Much of the software is based on novel methods utilizing geometric partial differential equations in conjunction with standard signal/image processing techniques as well as computer graphics facilitating man/machine interactions. As part of this enterprise, researchers have been trying to base biomedical engineering principles on rigorous mathematical foundations for the development of software methods to be integrated into complete therapy delivery systems. These systems support the more effective delivery of many image-guided procedures such as radiation therapy, biopsy, and minimally invasive surgery. We will show how mathematics may impact some of the main problems in this area, including image enhancement, registration, and segmentation. PMID:23645963

  7. Liver segmentation for CT images using GVF snake

    SciTech Connect

    Liu Fan; Zhao Binsheng; Kijewski, Peter K.; Wang Liang; Schwartz, Lawrence H.

    2005-12-15

    Accurate liver segmentation on computed tomography (CT) images is a challenging task especially at sites where surrounding tissues (e.g., stomach, kidney) have densities similar to that of the liver and lesions reside at the liver edges. We have developed a method for semiautomatic delineation of the liver contours on contrast-enhanced CT images. The method utilizes a snake algorithm with a gradient vector flow (GVF) field as its external force. To improve the performance of the GVF snake in the segmentation of the liver contour, an edge map was obtained with a Canny edge detector, followed by modifications using a liver template and a concavity removal algorithm. With the modified edge map, for which unwanted edges inside the liver were eliminated, the GVF field was computed and an initial liver contour was formed. The snake algorithm was then applied to obtain the actual liver contour. This algorithm was extended to segment the liver volume in a slice-by-slice fashion, where the result of the preceding slice constrained the segmentation of the adjacent slice. 551 two-dimensional liver images from 20 volumetric images with colorectal metastases spreading throughout the livers were delineated using this method, and also manually by a radiologist for evaluation. The difference ratio, which is defined as the percentage ratio of mismatching volume between the computer and the radiologist's results, ranged from 2.9% to 7.6% with a median value of 5.3%.

  8. Molecular Body Imaging: MR Imaging, CT, and US. Part I. Principles

    PubMed Central

    Kircher, Moritz F.

    2012-01-01

    Molecular imaging, generally defined as noninvasive imaging of cellular and subcellular events, has gained tremendous depth and breadth as a research and clinical discipline in recent years. The coalescence of major advances in engineering, molecular biology, chemistry, immunology, and genetics has fueled multi- and interdisciplinary innovations with the goal of driving clinical noninvasive imaging strategies that will ultimately allow disease identification, risk stratification, and monitoring of therapy effects with unparalleled sensitivity and specificity. Techniques that allow imaging of molecular and cellular events facilitate and go hand in hand with the development of molecular therapies, offering promise for successfully combining imaging with therapy. While traditionally nuclear medicine imaging techniques, in particular positron emission tomography (PET), PET combined with computed tomography (CT), and single photon emission computed tomography, have been the molecular imaging methods most familiar to clinicians, great advances have recently been made in developing imaging techniques that utilize magnetic resonance (MR), optical, CT, and ultrasonographic (US) imaging. In the first part of this review series, we present an overview of the principles of MR imaging-, CT-, and US-based molecular imaging strategies. © RSNA, 2012 PMID:22623690

  9. Accuracy of quantitative reconstructions in SPECT/CT imaging

    NASA Astrophysics Data System (ADS)

    Shcherbinin, S.; Celler, A.; Belhocine, T.; van der Werf, R.; Driedger, A.

    2008-09-01

    The goal of this study was to determine the quantitative accuracy of our OSEM-APDI reconstruction method based on SPECT/CT imaging for Tc-99m, In-111, I-123, and I-131 isotopes. Phantom studies were performed on a SPECT/low-dose multislice CT system (Infinia-Hawkeye-4 slice, GE Healthcare) using clinical acquisition protocols. Two radioactive sources were centrally and peripherally placed inside an anthropometric Thorax phantom filled with non-radioactive water. Corrections for attenuation, scatter, collimator blurring and collimator septal penetration were applied and their contribution to the overall accuracy of the reconstruction was evaluated. Reconstruction with the most comprehensive set of corrections resulted in activity estimation with error levels of 3-5% for all the isotopes.

  10. Usability Practice in Medical Imaging Application Development

    NASA Astrophysics Data System (ADS)

    Chen, Chufeng; Abdelnour-Nocera, Jose; Wells, Stephen; Pan, Nora

    Historically, development of medical imaging applications has focused on solving technical issues for small numbers of expert users. However, their use is now more mainstream and users are no longer willing to tolerate poor performance and usability. In this study we illustrate the application of user centred design methods in a medical imaging applications development company by using a usability comparative study of different regions of interest (ROI) tools. A use case analysis was used to judge usability efficiency and effectiveness of different ROI tools; and a user observation was also carried out which measured the accuracy achieved by these tools. We have found that useful results can be obtained by using these methods. We also generated some concrete suggestions that could be incorporated into future product development.

  11. Data sets for the qualification of volumetric CT as a quantitative imaging biomarker in lung cancer.

    PubMed

    Buckler, A J; Schwartz, L H; Petrick, N; McNitt-Gray, M; Zhao, B; Fenimore, C; Reeves, A P; Mozley, P D; Avila, R S

    2010-07-01

    The drug development industry is faced with increasing costs and decreasing success rates. New ways to understand biology as well as the increasing interest in personalized treatments for smaller patient segments requires new capabilities for the rapid assessment of treatment responses. Deployment of qualified imaging biomarkers lags apparent technology capabilities. The lack of consensus methods and qualification evidence needed for large-scale multi-center trials, as well as the standardization that allows them, are widely acknowledged to be the limiting factors. The current fragmentation in imaging vendor offerings, coupled with the independent activities of individual biopharmaceutical companies and their contract research organizations (CROs), may stand in the way of the greater opportunity were these efforts to be drawn together. A preliminary report, "Volumetric CT: a potential biomarker of response," of the Quantitative Imaging Biomarkers Alliance (QIBA) activity was presented at the Medical Imaging Continuum: Path Forward for Advancing the Uses of Medical Imaging in the Development of New Biopharmaceutical Products meeting of the Extended Pharmaceutical Research and Manufacturers of America (PhRMA) Imaging Group sponsored by the Drug Information Agency (DIA) in October 2008. The clinical context in Lung Cancer and a methodology for approaching the qualification of volumetric CT as a biomarker has since been reported [Acad. Radiol. 17, 100-106, 107-115 (2010)]. This report reviews the effort to collect and utilize publicly available data sets to provide a transparent environment in which to pursue the qualification activities in such a way as to allow independent peer review and verification of results. This article focuses specifically on our role as stewards of image sets for developing new tools. PMID:20640013

  12. Improved image quality for x-ray CT imaging of gel dosimeters

    SciTech Connect

    Kakakhel, M. B.; Kairn, T.; Kenny, J.; Trapp, J. V.

    2011-09-15

    Purpose: This study provides a simple method for improving precision of x-ray computed tomography (CT) scans of irradiated polymer gel dosimetry. The noise affecting CT scans of irradiated gels has been an impediment to the use of clinical CT scanners for gel dosimetry studies. Methods: In this study, it is shown that multiple scans of a single PAGAT gel dosimeter can be used to extrapolate a ''zero-scan'' image which displays a similar level of precision to an image obtained by averaging multiple CT images, without the compromised dose measurement resulting from the exposure of the gel to radiation from the CT scanner. Results: When extrapolating the zero-scan image, it is shown that exponential and simple linear fits to the relationship between Hounsfield unit and scan number, for each pixel in the image, provide an accurate indication of gel density. Conclusions: It is expected that this work will be utilized in the analysis of three-dimensional gel volumes irradiated using complex radiotherapy treatments.

  13. Optimal ''image-based'' weighting for energy-resolved CT

    SciTech Connect

    Schmidt, Taly Gilat

    2009-07-15

    This paper investigates a method of reconstructing images from energy-resolved CT data with negligible beam-hardening artifacts and improved contrast-to-nosie ratio (CNR) compared to conventional energy-weighting methods. Conceptually, the investigated method first reconstructs separate images from each energy bin. The final image is a linear combination of the energy-bin images, with the weights chosen to maximize the CNR in the final image. The optimal weight of a particular energy-bin image is derived to be proportional to the contrast-to-noise-variance ratio in that image. The investigated weighting method is referred to as ''image-based'' weighting, although, as will be described, the weights can be calculated and the energy-bin data combined prior to reconstruction. The performance of optimal image-based energy weighting with respect to CNR and beam-hardening artifacts was investigated through simulations and compared to that of energy integrating, photon counting, and previously studied optimal ''projection-based'' energy weighting. Two acquisitions were simulated: dedicated breast CT and a conventional thorax scan. The energy-resolving detector was simulated with five energy bins. Four methods of estimating the optimal weights were investigated, including task-specific and task-independent methods and methods that require a single reconstruction versus multiple reconstructions. Results demonstrated that optimal image-based weighting improved the CNR compared to energy-integrating weighting by factors of 1.15-1.6 depending on the task. Compared to photon-counting weighting, the CNR improvement ranged from 1.0 to 1.3. The CNR improvement factors were comparable to those of projection-based optimal energy weighting. The beam-hardening cupping artifact increased from 5.2% for energy-integrating weighting to 12.8% for optimal projection-based weighting, while optimal image-based weighting reduced the cupping to 0.6%. Overall, optimal image-based energy weighting

  14. Lung imaging in rodents using dual energy micro-CT

    NASA Astrophysics Data System (ADS)

    Badea, C. T.; Guo, X.; Clark, D.; Johnston, S. M.; Marshall, C.; Piantadosi, C.

    2012-03-01

    Dual energy CT imaging is expected to play a major role in the diagnostic arena as it provides material decomposition on an elemental basis. The purpose of this work is to investigate the use of dual energy micro-CT for the estimation of vascular, tissue, and air fractions in rodent lungs using a post-reconstruction three-material decomposition method. We have tested our method using both simulations and experimental work. Using simulations, we have estimated the accuracy limits of the decomposition for realistic micro-CT noise levels. Next, we performed experiments involving ex vivo lung imaging in which intact lungs were carefully removed from the thorax, were injected with an iodine-based contrast agent and inflated with air at different volume levels. Finally, we performed in vivo imaging studies in (n=5) C57BL/6 mice using fast prospective respiratory gating in endinspiration and end-expiration for three different levels of positive end-expiratory pressure (PEEP). Prior to imaging, mice were injected with a liposomal blood pool contrast agent. The mean accuracy values were for Air (95.5%), Blood (96%), and Tissue (92.4%). The absolute accuracy in determining all fraction materials was 94.6%. The minimum difference that we could detect in material fractions was 15%. As expected, an increase in PEEP levels for the living mouse resulted in statistically significant increases in air fractions at end-expiration, but no significant changes in end-inspiration. Our method has applicability in preclinical pulmonary studies where various physiological changes can occur as a result of genetic changes, lung disease, or drug effects.

  15. CT discrimination and image process on damage process of unsaturated compacted loess during triaxial creep

    NASA Astrophysics Data System (ADS)

    Li, Xiaojun; Jiang, Lihua; Tang, Yichuan

    2010-08-01

    The triaxial creep compression tests of compacted loess samples are conducted with a new set of modified triaxial compression apparatus. With the new apparatus, the loess sample can be scanned with CT machine at the same time during compression process. The different damage process of compacted loess sample is directly observed for the first time with CT images and CT numbers. The initiation mechanisms of loess micro-crack during different creep compression processes are analyzed with CT images.

  16. Pushing CT and MR Imaging to the Molecular Level for Studying the “Omics”: Current Challenges and Advancements

    PubMed Central

    Huang, Hsuan-Ming; Shih, Yi-Yu

    2014-01-01

    During the past decade, medical imaging has made the transition from anatomical imaging to functional and even molecular imaging. Such transition provides a great opportunity to begin the integration of imaging data and various levels of biological data. In particular, the integration of imaging data and multiomics data such as genomics, metabolomics, proteomics, and pharmacogenomics may open new avenues for predictive, preventive, and personalized medicine. However, to promote imaging-omics integration, the practical challenge of imaging techniques should be addressed. In this paper, we describe key challenges in two imaging techniques: computed tomography (CT) and magnetic resonance imaging (MRI) and then review existing technological advancements. Despite the fact that CT and MRI have different principles of image formation, both imaging techniques can provide high-resolution anatomical images while playing a more and more important role in providing molecular information. Such imaging techniques that enable single modality to image both the detailed anatomy and function of tissues and organs of the body will be beneficial in the imaging-omics field. PMID:24738056

  17. A recommender system for medical imaging diagnostic.

    PubMed

    Monteiro, Eriksson; Valente, Frederico; Costa, Carlos; Oliveira, José Luís

    2015-01-01

    The large volume of data captured daily in healthcare institutions is opening new and great perspectives about the best ways to use it towards improving clinical practice. In this paper we present a context-based recommender system to support medical imaging diagnostic. The system relies on data mining and context-based retrieval techniques to automatically lookup for relevant information that may help physicians in the diagnostic decision. PMID:25991188

  18. Association between Image Characteristics on Chest CT and Severe Pleural Adhesion during Lung Cancer Surgery

    PubMed Central

    Jin, Kwang Nam; Sung, Yong Won; Oh, Se Jin; Choi, Ye Ra; Cho, Hyoun; Choi, Jae-Sung; Moon, Hyeon-Jong

    2016-01-01

    The aim of this study was to investigate the association between image characteristics on preoperative chest CT and severe pleural adhesion during surgery in lung cancer patients. We included consecutive 124 patients who underwent lung cancer surgeries. Preoperative chest CT was retrospectively reviewed to assess pleural thickening or calcification, pulmonary calcified nodules, active pulmonary inflammation, extent of emphysema, interstitial pneumonitis, and bronchiectasis in the operated thorax. The extent of pleural thickening or calcification was visually estimated and categorized into two groups: localized and diffuse. We measured total size of pulmonary calcified nodules. The extent of emphysema, interstitial pneumonitis, and bronchiectasis was also evaluated with a visual scoring system. The occurrence of severe pleural adhesion during lung cancer surgery was retrospectively investigated from the electrical medical records. We performed logistic regression analysis to determine the association of image characteristic on chest CT with severe pleural adhesion. Localized pleural thickening was found in 8 patients (6.5%), localized pleural calcification in 8 (6.5%), pulmonary calcified nodules in 28 (22.6%), and active pulmonary inflammation in 22 (17.7%). There was no patient with diffuse pleural thickening or calcification in this study. Trivial, mild, and moderate emphysema was found in 31 (25.0%), 21 (16.9%), and 12 (9.7%) patients, respectively. Severe pleural adhesion was found in 31 (25.0%) patients. The association of localized pleural thickening or calcification on CT with severe pleural adhesion was not found (P = 0.405 and 0.107, respectively). Size of pulmonary calcified nodules and extent of emphysema were significant variables in a univariate analysis (P = 0.045 and 0.005, respectively). In a multivariate analysis, moderate emphysema was significantly associated with severe pleural adhesion (odds ratio of 11.202, P = 0.001). In conclusion, severe

  19. Towards a comprehensive CT image segmentation for thoracic organ radiation dose estimation and reporting

    NASA Astrophysics Data System (ADS)

    Lorenz, Cristian; Ruppertshofen, Heike; Vik, Torbjörn; Prinsen, Peter; Wiegert, Jens

    2014-03-01

    Administered dose of ionizing radiation during medical imaging is an issue of increasing concern for the patient, for the clinical community, and for respective regulatory bodies. CT radiation dose is currently estimated based on a set of very simplifying assumptions which do not take the actual body geometry and organ specific doses into account. This makes it very difficult to accurately report imaging related administered dose and to track it for different organs over the life of the patient. In this paper this deficit is addressed in a two-fold way. In a first step, the absorbed radiation dose in each image voxel is estimated based on a Monte-Carlo simulation of X-ray absorption and scattering. In a second step, the image is segmented into tissue types with different radio sensitivity. In combination this allows to calculate the effective dose as a weighted sum of the individual organ doses. The main purpose of this paper is to assess the feasibility of automatic organ specific dose estimation. With respect to a commercially applicable solution and respective robustness and efficiency requirements, we investigated the effect of dose sampling rather than integration over the organ volume. We focused on the thoracic anatomy as the exemplary body region, imaged frequently by CT. For image segmentation we applied a set of available approaches which allowed us to cover the main thoracic radio-sensitive tissue types. We applied the dose estimation approach to 10 thoracic CT datasets and evaluated segmentation accuracy and administered dose and could show that organ specific dose estimation can be achieved.

  20. Phantom based evaluation of CT to CBCT image registration for proton therapy dose recalculation

    NASA Astrophysics Data System (ADS)

    Landry, Guillaume; Dedes, George; Zöllner, Christoph; Handrack, Josefine; Janssens, Guillaume; Orban de Xivry, Jonathan; Reiner, Michael; Paganelli, Chiara; Riboldi, Marco; Kamp, Florian; Söhn, Matthias; Wilkens, Jan J.; Baroni, Guido; Belka, Claus; Parodi, Katia

    2015-01-01

    The ability to perform dose recalculation on the anatomy of the day is important in the context of adaptive proton therapy. The objective of this study was to investigate the use of deformable image registration (DIR) and cone beam CT (CBCT) imaging to generate the daily stopping power distribution of the patient. We investigated the deformation of the planning CT scan (pCT) onto daily CBCT images to generate a virtual CT (vCT) using a deformable phantom designed for the head and neck (H & N) region. The phantom was imaged at a planning CT scanner in planning configuration, yielding a pCT and in deformed, treatment day configuration, yielding a reference CT (refCT). The treatment day configuration was additionally scanned at a CBCT scanner. A Morphons DIR algorithm was used to generate a vCT. The accuracy of the vCT was evaluated by comparison to the refCT in terms of corresponding features as identified by an adaptive scale invariant feature transform (aSIFT) algorithm. Additionally, the vCT CT numbers were compared to those of the refCT using both profiles and regions of interest and the volumes and overlap (DICE coefficients) of various phantom structures were compared. The water equivalent thickness (WET) of the vCT, refCT and pCT were also compared to evaluate proton range differences. Proton dose distributions from the same initial fluence were calculated on the refCT, vCT and pCT and compared in terms of proton range. The method was tested on a clinical dataset using a replanning CT scan acquired close in time to a CBCT scan as reference using the WET evaluation. Results from the aSIFT investigation suggest a deformation accuracy of 2-3 mm. The use of the Morphon algorithm did not distort CT number intensity in uniform regions and WET differences between vCT and refCT were of the order of 2% of the proton range. This result was confirmed by proton dose calculations. The patient results were consistent with phantom observations. In conclusion, our phantom

  1. Using the ACR CT accreditation phantom for routine image quality assurance on both CT and CBCT imaging systems in a radiotherapy environment.

    PubMed

    Hobson, Maritza A; Soisson, Emilie T; Davis, Stephen D; Parker, William

    2014-01-01

    Image-guided radiation therapy using cone-beam computed tomography (CBCT) is becoming routine practice in modern radiation therapy. The purpose of this work was to develop an imaging QA program for CT and CBCT units in our department, based on the American College of Radiology (ACR) CT accreditation phantom. The phantom has four testing modules, permitting one to test CT number accuracy, slice width, low contrast resolution, image uniformity, in-plane distance accuracy, and high-contrast resolution reproducibly with suggested window/levels for image analysis. Additional tests for contrast-to-noise ratio (CNR) and noise were added using the polyethylene and acrylic plugs. Baseline values were obtained from CT simulator images acquired on a Phillips Brilliance Big Bore CT simulator and CBCT images acquired on three Varian CBCTs for the imaging protocols most used clinically. Images were then acquired quarterly over a period of two years. Images were exported via DICOM and analyzed manually using OsiriX. Baseline values were used to ensure that image quality remained consistent quarterly, and baselines were reset at any major maintenance or recalibration. Analysis of CT simulator images showed that image quality was within ACR guidelines for all tested scanning protocols. All three CBCT systems were unable to distinguish the low-contrast resolution plugs and had the same high-contrast resolution over all imaging protocols. Analysis of CBCT results over time determined a range of values that could be used to establish quantitative tolerance levels for image quality deterioration. While appropriate for the helical CT, the ACR phantom and guidelines could be modified to be more useful in evaluating CBCT systems. In addition, the observed values for the CT simulator were well within ACR tolerances. PMID:25207412

  2. Secured medical imaging over the Internet.

    PubMed

    Aslan, P; Lee, B; Kuo, R; Babayan, R K; Kavoussi, L R; Pavlin, K A; Preminger, G M

    1998-01-01

    The Internet has established itself as an affordable, extremely viable and ubiquitous communications network that can be easily accessed from virtually any point in the world. This makes it ideally suited for medical image communications. Issues regarding security and confidentiality of information on the Internet, however, need to be addressed for both occasional, individual users and consistent enterprise-wide users. In addition, the limited bandwidth of most Internet connections must be factored into the development of a realistic usermodel and resulting protocol. Open architecture issues must also be considered so that images can be communicated to recipients who do not have similar programs. Further, application-specific software is required to integrate image acquisition, encryption and transmission into a single, streamlined process. Using Photomailer software provided by PhysiTel Inc., the authors investigated the use of sending secured still images over the Internet. The scope of their investigation covered the use of the Internet for communicating images for consultation, referral, mentoring and education. Photomailer software was used at several local and remote sites. The program was used for both sending and receiving images. It was also used for sending images to recipients who did not have Photomailer, but instead relied on conventional email programs. The results of the investigation demonstrated that using products such as Photomailer, images could be quickly and easily communicated from one location to another via the Internet. In addition, the investigators were able to retrieve images off of their existing email accounts, thereby providing greater flexibility and convenience than other systems which require scheduled transmission of information on dedicated systems. We conclude that Photomailer and similar products may provide a significant benefit and improve communications among colleagues, providing an inexpensive means of sending secured

  3. Comparison of spectral CT imaging methods based a photon-counting detector: Experimental study

    NASA Astrophysics Data System (ADS)

    Lee, Youngjin; Lee, Seungwan; Kim, Hee-Joung

    2016-04-01

    Photon-counting detectors allow spectral computed tomography (CT) imaging using energy-resolved information from a polychromatic X-ray spectrum. The spectral CT images based on the photon-counting detectors are dependent on the energy ranges defined by energy bins for image acquisition. In this study, K-edge and energy weighting imaging methods were experimentally implemented by using a spectral CT system with a cadmium zinc telluride (CZT)-based photon-counting detector. The spectral CT images were obtained by various energy bins and compared in terms of CNR improvement for investigating the effect of energy bins and the efficiency of the spectral CT imaging methods. The results showed that the spectral CT image quality was improved by using the particular energy bins, which were optimized for each spectral CT imaging method and target material. The CNR improvement was different for the spectral CT imaging methods and target materials. It can be concluded that an appropriate selection of imaging method for each target material and the optimization of energy bin can maximize the quality of spectral CT images.

  4. Proton-induced x-ray fluorescence CT imaging

    SciTech Connect

    Bazalova-Carter, Magdalena Xing, Lei; Ahmad, Moiz; Matsuura, Taeko; Takao, Seishin; Shirato, Hiroki; Umegaki, Kikuo; Matsuo, Yuto; Fahrig, Rebecca

    2015-02-15

    Purpose: To demonstrate the feasibility of proton-induced x-ray fluorescence CT (pXFCT) imaging of gold in a small animal sized object by means of experiments and Monte Carlo (MC) simulations. Methods: First, proton-induced gold x-ray fluorescence (pXRF) was measured as a function of gold concentration. Vials of 2.2 cm in diameter filled with 0%–5% Au solutions were irradiated with a 220 MeV proton beam and x-ray fluorescence induced by the interaction of protons, and Au was detected with a 3 × 3 mm{sup 2} CdTe detector placed at 90° with respect to the incident proton beam at a distance of 45 cm from the vials. Second, a 7-cm diameter water phantom containing three 2.2-diameter vials with 3%–5% Au solutions was imaged with a 7-mm FWHM 220 MeV proton beam in a first generation CT scanning geometry. X-rays scattered perpendicular to the incident proton beam were acquired with the CdTe detector placed at 45 cm from the phantom positioned on a translation/rotation stage. Twenty one translational steps spaced by 3 mm at each of 36 projection angles spaced by 10° were acquired, and pXFCT images of the phantom were reconstructed with filtered back projection. A simplified geometry of the experimental data acquisition setup was modeled with the MC TOPAS code, and simulation results were compared to the experimental data. Results: A linear relationship between gold pXRF and gold concentration was observed in both experimental and MC simulation data (R{sup 2} > 0.99). All Au vials were apparent in the experimental and simulated pXFCT images. Specifically, the 3% Au vial was detectable in the experimental [contrast-to-noise ratio (CNR) = 5.8] and simulated (CNR = 11.5) pXFCT image. Due to fluorescence x-ray attenuation in the higher concentration vials, the 4% and 5% Au contrast were underestimated by 10% and 15%, respectively, in both the experimental and simulated pXFCT images. Conclusions: Proton-induced x-ray fluorescence CT imaging of 3%–5% gold solutions in a

  5. Proton-induced x-ray fluorescence CT imaging

    PubMed Central

    Bazalova-Carter, Magdalena; Ahmad, Moiz; Matsuura, Taeko; Takao, Seishin; Matsuo, Yuto; Fahrig, Rebecca; Shirato, Hiroki; Umegaki, Kikuo; Xing, Lei

    2015-01-01

    Purpose: To demonstrate the feasibility of proton-induced x-ray fluorescence CT (pXFCT) imaging of gold in a small animal sized object by means of experiments and Monte Carlo (MC) simulations. Methods: First, proton-induced gold x-ray fluorescence (pXRF) was measured as a function of gold concentration. Vials of 2.2 cm in diameter filled with 0%–5% Au solutions were irradiated with a 220 MeV proton beam and x-ray fluorescence induced by the interaction of protons, and Au was detected with a 3 × 3 mm2 CdTe detector placed at 90° with respect to the incident proton beam at a distance of 45 cm from the vials. Second, a 7-cm diameter water phantom containing three 2.2-diameter vials with 3%–5% Au solutions was imaged with a 7-mm FWHM 220 MeV proton beam in a first generation CT scanning geometry. X-rays scattered perpendicular to the incident proton beam were acquired with the CdTe detector placed at 45 cm from the phantom positioned on a translation/rotation stage. Twenty one translational steps spaced by 3 mm at each of 36 projection angles spaced by 10° were acquired, and pXFCT images of the phantom were reconstructed with filtered back projection. A simplified geometry of the experimental data acquisition setup was modeled with the MC TOPAS code, and simulation results were compared to the experimental data. Results: A linear relationship between gold pXRF and gold concentration was observed in both experimental and MC simulation data (R2 > 0.99). All Au vials were apparent in the experimental and simulated pXFCT images. Specifically, the 3% Au vial was detectable in the experimental [contrast-to-noise ratio (CNR) = 5.8] and simulated (CNR = 11.5) pXFCT image. Due to fluorescence x-ray attenuation in the higher concentration vials, the 4% and 5% Au contrast were underestimated by 10% and 15%, respectively, in both the experimental and simulated pXFCT images. Conclusions: Proton-induced x-ray fluorescence CT imaging of 3%–5% gold solutions in a small animal

  6. Method for reducing windmill artifacts in multislice CT images

    NASA Astrophysics Data System (ADS)

    Brown, Kevin M.; Žabic, Stanislav

    2011-03-01

    Thin-slice images reconstructed from helical multi-slice CT scans typically display artifacts known as windmill artifacts, which arise from not satisfying the Nyquist sampling criteria in the patient longitudinal direction. Since these are essentially aliasing artifacts, they can be reduced or removed by trading off resolution, either globally (by reconstructing thicker slices) or locally (by local smoothing of the strong gradients). The obvious drawback to this approach is the associated loss in resolution. Another approach is to utilize an x-ray tube with the capability to modulate the focal spot in the z-direction, to effectively improve the sampling rate. This work presents a new method for windmill artifact reduction based on total variation minimization in the image domain, which is capable of removing windmill artifacts while at the same time preserving the resolution of anatomic structures within the images. This is a big improvement over previous reconstruction methods that sacrifice resolution, and it provides practically the same benefits as a z-switching x-ray tube with a much simpler impact to the overall CT system.

  7. An Iterative CT Reconstruction Algorithm for Fast Fluid Flow Imaging.

    PubMed

    Van Eyndhoven, Geert; Batenburg, K Joost; Kazantsev, Daniil; Van Nieuwenhove, Vincent; Lee, Peter D; Dobson, Katherine J; Sijbers, Jan

    2015-11-01

    The study of fluid flow through solid matter by computed tomography (CT) imaging has many applications, ranging from petroleum and aquifer engineering to biomedical, manufacturing, and environmental research. To avoid motion artifacts, current experiments are often limited to slow fluid flow dynamics. This severely limits the applicability of the technique. In this paper, a new iterative CT reconstruction algorithm for improved a temporal/spatial resolution in the imaging of fluid flow through solid matter is introduced. The proposed algorithm exploits prior knowledge in two ways. First, the time-varying object is assumed to consist of stationary (the solid matter) and dynamic regions (the fluid flow). Second, the attenuation curve of a particular voxel in the dynamic region is modeled by a piecewise constant function over time, which is in accordance with the actual advancing fluid/air boundary. Quantitative and qualitative results on different simulation experiments and a real neutron tomography data set show that, in comparison with the state-of-the-art algorithms, the proposed algorithm allows reconstruction from substantially fewer projections per rotation without image quality loss. Therefore, the temporal resolution can be substantially increased, and thus fluid flow experiments with faster dynamics can be performed. PMID:26259219

  8. Segmentation and separation of venous vasculatures in liver CT images

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Hansen, Christian; Zidowitz, Stephan; Hahn, Horst K.

    2014-03-01

    Computer-aided analysis of venous vasculatures including hepatic veins and portal veins is important in liver surgery planning. The analysis normally consists of two important pre-processing tasks: segmenting both vasculatures and separating them from each other by assigning different labels. During the acquisition of multi-phase CT images, both of the venous vessels are enhanced by injected contrast agent and acquired either in a common phase or in two individual phases. The enhanced signals established by contrast agent are often not stably acquired due to non-optimal acquisition time. Inadequate contrast and the presence of large lesions in oncological patients, make the segmentation task quite challenging. To overcome these diffculties, we propose a framework with minimal user interactions to analyze venous vasculatures in multi-phase CT images. Firstly, presented vasculatures are automatically segmented adopting an efficient multi-scale Hessian-based vesselness filter. The initially segmented vessel trees are then converted to a graph representation, on which a series of graph filters are applied in post-processing steps to rule out irrelevant structures. Eventually, we develop a semi-automatic workow to refine the segmentation in the areas of inferior vena cava and entrance of portal veins, and to simultaneously separate hepatic veins from portal veins. Segmentation quality was evaluated with intensive tests enclosing 60 CT images from both healthy liver donors and oncological patients. To quantitatively measure the similarities between segmented and reference vessel trees, we propose three additional metrics: skeleton distance, branch coverage, and boundary surface distance, which are dedicated to quantifying the misalignment induced by both branching patterns and radii of two vessel trees.

  9. The cerebral imaging using vessel-around method in the perfusion CT of the human brain

    NASA Astrophysics Data System (ADS)

    Ahn, Choong-Il; Choi, Seung-Wook; Park, Seung-Chul; Shin, Yeong-Gil; Kim, Jae-Hyoung; Chong, Gi-Bong

    2005-04-01

    Perfusion CT has been successfully used as a functional imaging technique for diagnosis of patients with hyperacute stroke. However, the commonly used methods based on curve-fitting are time consuming. Numerous researchers have investigated to what extent Perfusion CT can be used for the quantitative assessment of cerebral ischemia and to rapidly obtain comprehensive information regarding the extent of ischemic damage in acute stroke patients. The aim of this study is to propose an alternative approach to rapidly obtain the brain perfusion mapping and to show the proposed cerebral flow imaging of the vessel and tissue in human brain be reliable and useful. Our main design concern was algorithmic speed, robustness and automation in order to allow its potential use in the emergency situation of acute stroke. To obtain a more effective mapping, we analyzed the signal characteristics of Perfusion CT and defined the vessel-around model which includes the vessel and tissue. We proposed a nonparametric vessel-around approach which automatically discriminates the vessel and tissue around vessel from non-interested brain matter stratifying the level of maximum enhancement of pixel-based TAC. The stratification of pixel-based TAC was executed using the mean and standard deviation of the signal intensity of each pixel and mapped to the cerebral flow imaging. The defined vessel-around model was used to show the cerebral flow imaging and to specify the area of markedly reduced perfusion with loss of function of still viable neurons. Perfusion CT is a fast and practical technique for routine clinical application. It provides substantial and important additional information for the selection of the optimal treatment strategy for patients with hyperacute stroke. The vessel-around approach reduces the computation time significantly when compared with the perfusion imaging using the GVF. The proposed cerebral imaging shows reliable results which are validated by physicians and

  10. Simulation of four-dimensional CT images from deformable registration between inhale and exhale breath-hold CT scans

    SciTech Connect

    Sarrut, David; Boldea, Vlad; Miguet, Serge; Ginestet, Chantal

    2006-03-15

    Purpose: We propose to simulate an artificial four-dimensional (4-D) CT image of the thorax during breathing. It is performed by deformable registration of two CT scans acquired at inhale and exhale breath-hold. Materials and methods: Breath-hold images were acquired with the ABC (Active Breathing Coordinator) system. Dense deformable registrations were performed. The method was a minimization of the sum of squared differences (SSD) using an approximated second-order gradient. Gaussian and linear-elastic vector field regularizations were compared. A new preprocessing step, called a priori lung density modification (APLDM), was proposed to take into account lung density changes due to inspiration. It consisted of modulating the lung densities in one image according to the densities in the other, in order to make them comparable. Simulated 4-D images were then built by vector field interpolation and image resampling of the two initial CT images. A variation in the lung density was taken into account to generate intermediate artificial CT images. The Jacobian of the deformation was used to compute voxel values in Hounsfield units. The accuracy of the deformable registration was assessed by the spatial correspondence of anatomic landmarks located by experts. Results: APLDM produced statistically significantly better results than the reference method (registration without APLDM preprocessing). The mean (and standard deviation) of distances between automatically found landmark positions and landmarks set by experts were 2.7(1.1) mm with APLDM, and 6.3(3.8) mm without. Interexpert variability was 2.3(1.2) mm. The differences between Gaussian and linear elastic regularizations were not statistically significant. In the second experiment using 4-D images, the mean difference between automatic and manual landmark positions for intermediate CT images was 2.6(2.0) mm. Conclusion: The generation of 4-D CT images by deformable registration of inhale and exhale CT images is

  11. Managing waiting times in diagnostic medical imaging

    PubMed Central

    Nuti, Sabina; Vainieri, Milena

    2012-01-01

    Objective This paper aims to analyse the variation in the delivery of diagnostic imaging services in order to suggest possible solutions for the reduction of waiting times, increase the quality of services and reduce financial costs. Design This study provides a logic model to manage waiting times in a regional context. Waiting times measured per day were compared on the basis of the variability in the use rates of CT and MRI examinations in Tuscany for the population, as well as on the basis of the capacity offered with respect to the number of radiologists available. The analysis was performed at the local health authority level to support the decision-making process of local managers. Setting Diagnostic imaging services, in particular the CT and MRI examinations. The study involved all the 12 local health authorities that provide services for 3.7 million inhabitants of the Italian Tuscany Region. Primary and secondary outcome measures Participants: the study uses regional administrative data on outpatients and survey data on inpatient diagnostic examinations in order to measure productivity. Primary and secondary outcome measures The study uses the volumes per 1000 inhabitants, the days of waiting times and the number of examinations per radiologist. Variability was measured using the traditional SD measures. Results A significant variation in areas considered homogeneous in terms of age, gender or mortality may indicate that the use of radiological services is not optimal and underuse or overuse occurs and that there is room for improvement in the service organisation. Conclusions Considering that there is a high level of variability among district use rates and waiting times, this study provides managers with a specific tool to find the cause of the problem, identify a possible solution, assess the financial impact and initiate the eventual reduction of waste. PMID:23242480

  12. ICG fluorescence imaging and its medical applications

    NASA Astrophysics Data System (ADS)

    Miwa, Mitsuharu; Shikayama, Takahiro

    2008-12-01

    This paper presents a novel optical angiography system, and introduces its medical applications. We developed the optical enhanced imaging system which can observe the blood and lymphatic vessels as the Indocyanine green (ICG) fluorescence image. The imaging system consists of 760nm light emitted diode (LED) as excite light, CCD camera as a detector, a high-pass optical filter in front of the CCD and video processing system. The advantage of ICG fluorescence method is safe (radiation free), high sensitive, real time monitoring of blood and/or lymphatic flow, small size, easy to operate and cost effective compared to conventional X-ray angiography or scintigraphy. We have applied this method to several clinical applications such as breast cancer sentinel lymph node (SLN) navigation, lymph edema diagnostic and identification of liver segmentation. In each application, ICG fluorescence method shows useful result. It's indicated that this method is promising technique as optical angiography.

  13. The quest for standards in medical imaging.

    PubMed

    Gibaud, Bernard

    2011-05-01

    This article focuses on standards supporting interoperability and system integration in the medical imaging domain. We introduce the basic concepts and actors and we review the most salient achievements in this domain, especially with the DICOM standard, and the definition of IHE integration profiles. We analyze and discuss what was successful, and what could still be more widely adopted by industry. We then sketch out a perspective of what should be done next, based on our vision of new requirements for the next decade. In particular, we discuss the challenges of a more explicit sharing of image and image processing semantics, and we discuss the help that semantic web technologies (and especially ontologies) may bring to achieving this goal. PMID:20605693

  14. CT and MR Imaging Findings of Pancreatic Paragangliomas

    PubMed Central

    Liang, Wenjie; Xu, Shunliang

    2016-01-01

    Abstract Previous studies on pancreatic paraganglioma, a rare neoplasm, have primarily reported its ultrasound and routine and contrast-enhanced computed tomography (CT) findings. To our knowledge, we are the first to report the contrast-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) sequence findings of pancreatic paraganglioma. A male patient, ages 41 years, was admitted to our hospital due to a pancreatic space-occupying lesion that had been present for more than 10 days. The patient had no obvious discomfort. He had a history of hypertension and hyperthyroidism. Physical examination revealed upper abdominal tenderness without a palpable mass. Routine and contrast-enhanced abdominal CT showed a soft tissue mass at the pancreatic head/uncinate process, with patchy calcification within the lesion. On a contrast-enhanced CT scan, severe enhancement of the mass in the arterial phase was noted, as was slightly reduced but still marked enhancement in the venous phase. The celiac trunk and superior mesenteric artery segment were wrapped by the tumor. Thickened, tortuous vessels were observed at the lesion edges, around which there were multiple enlarged lymph nodes. The main pancreatic duct was markedly dilated. Routine and contrast-enhanced pancreatic MRI demonstrated an abnormal nodular signal in the pancreatic head/uncinate process that was approximately 4.3 × 6.4 cm2 in size. T1-weighted imaging (T1WI) revealed hypointensity, whereas T2-weighted imaging (T2WI) revealed nonhomogeneous, slight hyperintensity. Patchy hypointensity on both T1WI and T2WI was observed within the lesion. DWI showed slight hyperintensity. Grossly heterogeneous enhancement of the mass was observed on a contrast-enhanced MRI scan, with the tumor wrapped around the adjacent vasculature, and multiple enlarged lymph nodes were observed peripherally. After preoperative preparation, the patient underwent pancreatoduodenectomy. Histopathology and

  15. Deblurring Computed Tomography Medical Images Using a Novel Amended Landweber Algorithm.

    PubMed

    Al-Ameen, Zohair; Sulong, Ghazali

    2015-09-01

    In computed tomography (CT), blurring occurs due to different hardware or software errors and hides certain medical details that are present in an image. Image blur is difficult to avoid in many circumstances and can frequently ruin an image. For this, many methods have been developed to reduce the blurring artifact from CT images. The problems with these methods are the high implementation time, noise amplification and boundary artifacts. Hence, this article presents an amended version of the iterative Landweber algorithm to attain artifact-free boundaries and less noise amplification in a faster application time. In this study, both synthetic and real blurred CT images are used to validate the proposed method properly. Similarly, the quality of the processed synthetic images is measured using the feature similarity index, structural similarity and visual information fidelity in pixel domain metrics. Finally, the results obtained from intensive experiments and performance evaluations show the efficiency of the proposed algorithm, which has potential as a new approach in medical image processing. PMID:26199211

  16. Cochlear implant candidates: assessment with CT and MR imaging.

    PubMed

    Harnsberger, H R; Dart, D J; Parkin, J L; Smoker, W R; Osborn, A G

    1987-07-01

    Eighty-seven patients with severe to profound hearing loss were evaluated for possible placement of a multichannel cochlear implant hearing device. After initial clinical screening, 42 patients underwent computed tomographic (CT) examination. Five of these patients were also examined with magnetic resonance (MR) imaging. Twenty-two patients received implants. CT of the middle and inner ear was normal in 24 patients (57.1%) and showed labyrinthine ossification in 12 (28.6%), cochlear or fenestral otosclerosis (or both) in four (9.5%), and congenital cochlear malformation in two (4.8%). The information provided by CT was used to (a) exclude patients in whom multichannel cochlear implantation would most likely be unsuccessful (owing to obliterative labyrinthine ossification, or congenital cochlear malformation, severe cochlear, or fenestral otosclerosis), (b) help select the best ear for implantation, and (c) provide a preoperative picture of normal variants and avoidable surgical pitfalls. MR experience is limited but assessment of the size of the cochlear nerve and the membranous labyrinth is possible with this modality and may provide additional information in the evaluation of these patients. PMID:3108956

  17. Investigation of uncertainties in image registration of cone beam CT to CT on an image-guided radiotherapy system

    NASA Astrophysics Data System (ADS)

    Sykes, J. R.; Brettle, D. S.; Magee, D. R.; Thwaites, D. I.

    2009-12-01

    Methods of measuring uncertainties in rigid body image registration of fan beam computed tomography (FBCT) to cone beam CT (CBCT) have been developed for automatic image registration algorithms in a commercial image guidance system (Synergy, Elekta, UK). The relationships between image registration uncertainty and both imaging dose and image resolution have been investigated with an anthropomorphic skull phantom and further measurements performed with patient images of the head. A new metric of target registration error is proposed. The metric calculates the mean distance traversed by a set of equi-spaced points on the surface of a 5 cm sphere, centred at the isocentre when transformed by the residual error of registration. Studies aimed at giving practical guidance on the use of the Synergy automated image registration, including choice of algorithm and use of the Clipbox are reported. The chamfer-matching algorithm was found to be highly robust to the increased noise induced by low-dose acquisitions. This would allow the imaging dose to be reduced from the current clinical norm of 2 mGy to 0.2 mGy without a clinically significant loss of accuracy. A study of the effect of FBCT slice thickness/spacing and CBCT voxel size showed that 2.5 mm and 1 mm, respectively, gave acceptable image registration performance. Registration failures were highly infrequent if the misalignment was typical of normal clinical set-up errors and these were easily identified. The standard deviation of translational registration errors, measured with patient images, was 0.5 mm on the surface of a 5 cm sphere centred on the treatment centre. The chamfer algorithm is suitable for routine clinical use with minimal need for close inspection of image misalignment.

  18. Investigation of uncertainties in image registration of cone beam CT to CT on an image-guided radiotherapy system.

    PubMed

    Sykes, J R; Brettle, D S; Magee, D R; Thwaites, D I

    2009-12-21

    Methods of measuring uncertainties in rigid body image registration of fan beam computed tomography (FBCT) to cone beam CT (CBCT) have been developed for automatic image registration algorithms in a commercial image guidance system (Synergy, Elekta, UK). The relationships between image registration uncertainty and both imaging dose and image resolution have been investigated with an anthropomorphic skull phantom and further measurements performed with patient images of the head. A new metric of target registration error is proposed. The metric calculates the mean distance traversed by a set of equi-spaced points on the surface of a 5 cm sphere, centred at the isocentre when transformed by the residual error of registration. Studies aimed at giving practical guidance on the use of the Synergy automated image registration, including choice of algorithm and use of the Clipbox are reported. The chamfer-matching algorithm was found to be highly robust to the increased noise induced by low-dose acquisitions. This would allow the imaging dose to be reduced from the current clinical norm of 2 mGy to 0.2 mGy without a clinically significant loss of accuracy. A study of the effect of FBCT slice thickness/spacing and CBCT voxel size showed that 2.5 mm and 1 mm, respectively, gave acceptable image registration performance. Registration failures were highly infrequent if the misalignment was typical of normal clinical set-up errors and these were easily identified. The standard deviation of translational registration errors, measured with patient images, was 0.5 mm on the surface of a 5 cm sphere centred on the treatment centre. The chamfer algorithm is suitable for routine clinical use with minimal need for close inspection of image misalignment. PMID:19926913

  19. Quantification of heterogeneity observed in medical images

    PubMed Central

    2013-01-01

    Background There has been much recent interest in the quantification of visually evident heterogeneity within functional grayscale medical images, such as those obtained via magnetic resonance or positron emission tomography. In the case of images of cancerous tumors, variations in grayscale intensity imply variations in crucial tumor biology. Despite these considerable clinical implications, there is as yet no standardized method for measuring the heterogeneity observed via these imaging modalities. Methods In this work, we motivate and derive a statistical measure of image heterogeneity. This statistic measures the distance-dependent average deviation from the smoothest intensity gradation feasible. We show how this statistic may be used to automatically rank images of in vivo human tumors in order of increasing heterogeneity. We test this method against the current practice of ranking images via expert visual inspection. Results We find that this statistic provides a means of heterogeneity quantification beyond that given by other statistics traditionally used for the same purpose. We demonstrate the effect of tumor shape upon our ranking method and find the method applicable to a wide variety of clinically relevant tumor images. We find that the automated heterogeneity rankings agree very closely with those performed visually by experts. Conclusions These results indicate that our automated method may be used reliably to rank, in order of increasing heterogeneity, tumor images whether or not object shape is considered to contribute to that heterogeneity. Automated heterogeneity ranking yields objective results which are more consistent than visual rankings. Reducing variability in image interpretation will enable more researchers to better study potential clinical implications of observed tumor heterogeneity. PMID:23453000

  20. Multilayer descriptors for medical image classification.

    PubMed

    Lumini, Alessandra; Nanni, Loris; Brahnam, Sheryl

    2016-05-01

    In this paper, we propose a new method for improving the performance of 2D descriptors by building an n-layer image using different preprocessing approaches from which multilayer descriptors are extracted and used as feature vectors for training a Support Vector Machine. The different preprocessing approaches are used to build different n-layer images (n=3, n=5, etc.). We test both color and gray-level images, two well-known texture descriptors (Local Phase Quantization and Local Binary Pattern), and three of their variants suited for n-layer images (Volume Local Phase Quantization, Local Phase Quantization Three-Orthogonal-Planes, and Volume Local Binary Patterns). Our results show that multilayers and texture descriptors can be combined to outperform the standard single-layer approaches. Experiments on 10 datasets demonstrate the generalizability of the proposed descriptors. Most of these datasets are medical, but in each case the images are very different. Two datasets are completely unrelated to medicine and are included to demonstrate the discriminative power of the proposed descriptors across very different image recognition tasks. A MATLAB version of the complete system developed in this paper will be made available at https://www.dei.unipd.it/node/2357. PMID:26656952

  1. Model attraction in medical image object recognition

    NASA Astrophysics Data System (ADS)

    Tascini, Guido; Zingaretti, Primo

    1995-04-01

    This paper presents as new approach to image recognition based on a general attraction principle. A cognitive recognition is governed by a 'focus on attention' process that concentrates on the visual data subset of task- relevant type only. Our model-based approach combines it with another process, focus on attraction, which concentrates on the transformations of visual data having relevance for the matching. The recognition process is characterized by an intentional evolution of the visual data. This chain of image transformations is viewed as driven by an attraction field that attempts to reduce the distance between the image-point and the model-point in the feature space. The field sources are determined during a learning phase, by supplying the system with a training set. The paper describes a medical interpretation case in the feature space, concerning human skin lesions. The samples of the training set, supplied by the dermatologists, allow the system to learn models of lesions in terms of features such as hue factor, asymmetry factor, and asperity factor. The comparison of the visual data with the model derives the trend of image transformations, allowing a better definition of the given image and its classification. The algorithms are implemented in C language on a PC equipped with Matrox Image Series IM-1280 acquisition and processing boards. The work is now in progress.

  2. SU-C-17A-03: Evaluation of Deformable Image Registration Methods Between MRI and CT for Prostate Cancer Radiotherapy

    SciTech Connect

    Wen, N; Glide-Hurst, C; Zhong, H; Chin, K; Kumarasiri, A; Liu, C; Liu, M; Siddiqui, S

    2014-06-15

    Purpose: We evaluated the performance of two commercially available and one open source B-Spline deformable image registration (DIR) algorithms between T2-weighted MRI and treatment planning CT using the DICE indices. Methods: CT simulation (CT-SIM) and MR simulation (MR-SIM) for four prostate cancer patients were conducted on the same day using the same setup and immobilization devices. CT images (120 kVp, 500 mAs, voxel size = 1.1x1.1x3.0 mm3) were acquired using an open-bore CT scanner. T2-weighted Turbo Spine Echo (T2W-TSE) images (TE/TR/α = 80/4560 ms/90°, voxel size = 0.7×0.7×2.5 mm3) were scanned on a 1.0T high field open MR-SIM. Prostates, seminal vesicles, rectum and bladders were delineated on both T2W-TSE and CT images by the attending physician. T2W-TSE images were registered to CT images using three DIR algorithms, SmartAdapt (Varian), Velocity AI (Velocity) and Elastix (Klein et al 2010) and contours were propagated. DIR results were evaluated quantitatively or qualitatively by image comparison and calculating organ DICE indices. Results: Significant differences in the contours of prostate and seminal vesicles were observed between MR and CT. On average, volume changes of the propagated contours were 5%, 2%, 160% and 8% for the prostate, seminal vesicles, bladder and rectum respectively. Corresponding mean DICE indices were 0.7, 0.5, 0.8, and 0.7. The intraclass correlation coefficient (ICC) was 0.9 among three algorithms for the Dice indices. Conclusion: Three DIR algorithms for CT/MR registration yielded similar results for organ propagation. Due to the different soft tissue contrasts between MRI and CT, organ delineation of prostate and SVs varied significantly, thus efforts to develop other DIR evaluation metrics are warranted. Conflict of interest: Submitting institution has research agreements with Varian Medical System and Philips Healthcare.

  3. Development of proton CT imaging system using plastic scintillator and CCD camera.

    PubMed

    Tanaka, Sodai; Nishio, Teiji; Matsushita, Keiichiro; Tsuneda, Masato; Kabuki, Shigeto; Uesaka, Mitsuru

    2016-06-01

    A proton computed tomography (pCT) imaging system was constructed for evaluation of the error of an x-ray CT (xCT)-to-WEL (water-equivalent length) conversion in treatment planning for proton therapy. In this system, the scintillation light integrated along the beam direction is obtained by photography using the CCD camera, which enables fast and easy data acquisition. The light intensity is converted to the range of the proton beam using a light-to-range conversion table made beforehand, and a pCT image is reconstructed. An experiment for demonstration of the pCT system was performed using a 70 MeV proton beam provided by the AVF930 cyclotron at the National Institute of Radiological Sciences. Three-dimensional pCT images were reconstructed from the experimental data. A thin structure of approximately 1 mm was clearly observed, with spatial resolution of pCT images at the same level as that of xCT images. The pCT images of various substances were reconstructed to evaluate the pixel value of pCT images. The image quality was investigated with regard to deterioration including multiple Coulomb scattering. PMID:27191962

  4. Development of proton CT imaging system using plastic scintillator and CCD camera

    NASA Astrophysics Data System (ADS)

    Tanaka, Sodai; Nishio, Teiji; Matsushita, Keiichiro; Tsuneda, Masato; Kabuki, Shigeto; Uesaka, Mitsuru

    2016-06-01

    A proton computed tomography (pCT) imaging system was constructed for evaluation of the error of an x-ray CT (xCT)-to-WEL (water-equivalent length) conversion in treatment planning for proton therapy. In this system, the scintillation light integrated along the beam direction is obtained by photography using the CCD camera, which enables fast and easy data acquisition. The light intensity is converted to the range of the proton beam using a light-to-range conversion table made beforehand, and a pCT image is reconstructed. An experiment for demonstration of the pCT system was performed using a 70 MeV proton beam provided by the AVF930 cyclotron at the National Institute of Radiological Sciences. Three-dimensional pCT images were reconstructed from the experimental data. A thin structure of approximately 1 mm was clearly observed, with spatial resolution of pCT images at the same level as that of xCT images. The pCT images of various substances were reconstructed to evaluate the pixel value of pCT images. The image quality was investigated with regard to deterioration including multiple Coulomb scattering.

  5. Diagnostic accuracy at several reduced radiation dose levels for CT imaging in the diagnosis of appendicitis

    NASA Astrophysics Data System (ADS)

    Zhang, Di; Khatonabadi, Maryam; Kim, Hyun; Jude, Matilda; Zaragoza, Edward; Lee, Margaret; Patel, Maitraya; Poon, Cheryce; Douek, Michael; Andrews-Tang, Denise; Doepke, Laura; McNitt-Gray, Shawn; Cagnon, Chris; DeMarco, John; McNitt-Gray, Michael

    2012-03-01

    Purpose: While several studies have investigated the tradeoffs between radiation dose and image quality (noise) in CT imaging, the purpose of this study was to take this analysis a step further by investigating the tradeoffs between patient radiation dose (including organ dose) and diagnostic accuracy in diagnosis of appendicitis using CT. Methods: This study was IRB approved and utilized data from 20 patients who underwent clinical CT exams for indications of appendicitis. Medical record review established true diagnosis of appendicitis, with 10 positives and 10 negatives. A validated software tool used raw projection data from each scan to create simulated images at lower dose levels (70%, 50%, 30%, 20% of original). An observer study was performed with 6 radiologists reviewing each case at each dose level in random order over several sessions. Readers assessed image quality and provided confidence in their diagnosis of appendicitis, each on a 5 point scale. Liver doses at each case and each dose level were estimated using Monte Carlo simulation based methods. Results: Overall diagnostic accuracy varies across dose levels: 92%, 93%, 91%, 90% and 90% across the 100%, 70%, 50%, 30% and 20% dose levels respectively. And it is 93%, 95%, 88%, 90% and 90% across the 13.5-22mGy, 9.6-13.5mGy, 6.4-9.6mGy, 4-6.4mGy, and 2-4mGy liver dose ranges respectively. Only 4 out of 600 observations were rated "unacceptable" for image quality. Conclusion: The results from this pilot study indicate that the diagnostic accuracy does not change dramatically even at significantly reduced radiation dose.

  6. Deep convolutional networks for pancreas segmentation in CT imaging

    NASA Astrophysics Data System (ADS)

    Roth, Holger R.; Farag, Amal; Lu, Le; Turkbey, Evrim B.; Summers, Ronald M.

    2015-03-01

    Automatic organ segmentation is an important prerequisite for many computer-aided diagnosis systems. The high anatomical variability of organs in the abdomen, such as the pancreas, prevents many segmentation methods from achieving high accuracies when compared to state-of-the-art segmentation of organs like the liver, heart or kidneys. Recently, the availability of large annotated training sets and the accessibility of affordable parallel computing resources via GPUs have made it feasible for "deep learning" methods such as convolutional networks (ConvNets) to succeed in image classification tasks. These methods have the advantage that used classification features are trained directly from the imaging data. We present a fully-automated bottom-up method for pancreas segmentation in computed tomography (CT) images of the abdomen. The method is based on hierarchical coarse-to-fine classification of local image regions (superpixels). Superpixels are extracted from the abdominal region using Simple Linear Iterative Clustering (SLIC). An initial probability response map is generated, using patch-level confidences and a two-level cascade of random forest classifiers, from which superpixel regions with probabilities larger 0.5 are retained. These retained superpixels serve as a highly sensitive initial input of the pancreas and its surroundings to a ConvNet that samples a bounding box around each superpixel at different scales (and random non-rigid deformations at training time) in order to assign a more distinct probability of each superpixel region being pancreas or not. We evaluate our method on CT images of 82 patients (60 for training, 2 for validation, and 20 for testing). Using ConvNets we achieve maximum Dice scores of an average 68% +/- 10% (range, 43-80%) in testing. This shows promise for accurate pancreas segmentation, using a deep learning approach and compares favorably to state-of-the-art methods.

  7. Dose and image quality for a cone-beam C-arm CT system

    SciTech Connect

    Fahrig, Rebecca; Dixon, Robert; Payne, Thomas; Morin, Richard L.; Ganguly, Arundhuti; Strobel, Norbert

    2006-12-15

    We assess dose and image quality of a state-of-the-art angiographic C-arm system (Axiom Artis dTA, Siemens Medical Solutions, Forchheim, Germany) for three-dimensional neuro-imaging at various dose levels and tube voltages and an associated measurement method. Unlike conventional CT, the beam length covers the entire phantom, hence, the concept of computed tomography dose index (CTDI) is not the metric of choice, and one can revert to conventional dosimetry methods by directly measuring the dose at various points using a small ion chamber. This method allows us to define and compute a new dose metric that is appropriate for a direct comparison with the familiar CTDI{sub W} of conventional CT. A perception study involving the CATPHAN 600 indicates that one can expect to see at least the 9 mm inset with 0.5% nominal contrast at the recommended head-scan dose (60 mGy) when using tube voltages ranging from 70 kVp to 125 kVp. When analyzing the impact of tube voltage on image quality at a fixed dose, we found that lower tube voltages gave improved low contrast detectability for small-diameter objects. The relationships between kVp, image noise, dose, and contrast perception are discussed.

  8. Application of the optically stimulated luminescence (OSL) technique for mouse dosimetry in micro-CT imaging

    SciTech Connect

    Vrigneaud, Jean-Marc; Courteau, Alan; Oudot, Alexandra; Collin, Bertrand; Ranouil, Julien; Morgand, Loïc; Raguin, Olivier; Walker, Paul; Brunotte, François

    2013-12-15

    Purpose: Micro-CT is considered to be a powerful tool to investigate various models of disease on anesthetized animals. In longitudinal studies, the radiation dose delivered by the micro-CT to the same animal is a major concern as it could potentially induce spurious effects in experimental results. Optically stimulated luminescence dosimeters (OSLDs) are a relatively new kind of detector used in radiation dosimetry for medical applications. The aim of this work was to assess the dose delivered by the CT component of a micro-SPECT (single-photon emission computed tomography)/CT camera during a typical whole-body mouse study, using commercially available OSLDs based on Al{sub 2}O{sub 3}:C crystals.Methods: CTDI (computed tomography dose index) was measured in micro-CT with a properly calibrated pencil ionization chamber using a rat-like phantom (60 mm in diameter) and a mouse-like phantom (30 mm in diameter). OSLDs were checked for reproducibility and linearity in the range of doses delivered by the micro-CT. Dose measurements obtained with OSLDs were compared to those of the ionization chamber to correct for the radiation quality dependence of OSLDs in the low-kV range. Doses to tissue were then investigated in phantoms and cadavers. A 30 mm diameter phantom, specifically designed to insert OSLDs, was used to assess radiation dose over a typical whole-body mouse imaging study. Eighteen healthy female BALB/c mice weighing 27.1 ± 0.8 g (1 SD) were euthanized for small animal measurements. OLSDs were placed externally or implanted internally in nine different locations by an experienced animal technician. Five commonly used micro-CT protocols were investigated.Results: CTDI measurements were between 78.0 ± 2.1 and 110.7 ± 3.0 mGy for the rat-like phantom and between 169.3 ± 4.6 and 203.6 ± 5.5 mGy for the mouse-like phantom. On average, the displayed CTDI at the operator console was underestimated by 1.19 for the rat-like phantom and 2.36 for the mouse

  9. Twofold processing for denoising ultrasound medical images.

    PubMed

    Kishore, P V V; Kumar, K V V; Kumar, D Anil; Prasad, M V D; Goutham, E N D; Rahul, R; Krishna, C B S Vamsi; Sandeep, Y

    2015-01-01

    Ultrasound medical (US) imaging non-invasively pictures inside of a human body for disease diagnostics. Speckle noise attacks ultrasound images degrading their visual quality. A twofold processing algorithm is proposed in this work to reduce this multiplicative speckle noise. First fold used block based thresholding, both hard (BHT) and soft (BST), on pixels in wavelet domain with 8, 16, 32 and 64 non-overlapping block sizes. This first fold process is a better denoising method for reducing speckle and also inducing object of interest blurring. The second fold process initiates to restore object boundaries and texture with adaptive wavelet fusion. The degraded object restoration in block thresholded US image is carried through wavelet coefficient fusion of object in original US mage and block thresholded US image. Fusion rules and wavelet decomposition levels are made adaptive for each block using gradient histograms with normalized differential mean (NDF) to introduce highest level of contrast between the denoised pixels and the object pixels in the resultant image. Thus the proposed twofold methods are named as adaptive NDF block fusion with hard and soft thresholding (ANBF-HT and ANBF-ST). The results indicate visual quality improvement to an interesting level with the proposed twofold processing, where the first fold removes noise and second fold restores object properties. Peak signal to noise ratio (PSNR), normalized cross correlation coefficient (NCC), edge strength (ES), image quality Index (IQI) and structural similarity index (SSIM), measure the quantitative quality of the twofold processing technique. Validation of the proposed method is done by comparing with anisotropic diffusion (AD), total variational filtering (TVF) and empirical mode decomposition (EMD) for enhancement of US images. The US images are provided by AMMA hospital radiology labs at Vijayawada, India. PMID:26697285

  10. Single 3D cell segmentation from optical CT microscope images

    NASA Astrophysics Data System (ADS)

    Xie, Yiting; Reeves, Anthony P.

    2014-03-01

    The automated segmentation of the nucleus and cytoplasm regions in 3D optical CT microscope images has been achieved with two methods, a global threshold gradient based approach and a graph-cut approach. For the first method, the first two peaks of a gradient figure of merit curve are selected as the thresholds for cytoplasm and nucleus segmentation. The second method applies a graph-cut segmentation twice: the first identifies the nucleus region and the second identifies the cytoplasm region. Image segmentation of single cells is important for automated disease diagnostic systems. The segmentation methods were evaluated with 200 3D images consisting of 40 samples of 5 different cell types. The cell types consisted of columnar, macrophage, metaplastic and squamous human cells and cultured A549 cancer cells. The segmented cells were compared with both 2D and 3D reference images and the quality of segmentation was determined by the Dice Similarity Coefficient (DSC). In general, the graph-cut method had a superior performance to the gradient-based method. The graph-cut method achieved an average DSC of 86% and 72% for nucleus and cytoplasm segmentations respectively for the 2D reference images and 83% and 75% for the 3D reference images. The gradient method achieved an average DSC of 72% and 51% for nucleus and cytoplasm segmentation for the 2D reference images and 71% and 51% for the 3D reference images. The DSC of cytoplasm segmentation was significantly lower than for the nucleus since the cytoplasm was not differentiated as well by image intensity from the background.

  11. Medical image archive node simulation and architecture

    NASA Astrophysics Data System (ADS)

    Chiang, Ted T.; Tang, Yau-Kuo

    1996-05-01

    It is a well known fact that managed care and new treatment technologies are revolutionizing the health care provider world. Community Health Information Network and Computer-based Patient Record projects are underway throughout the United States. More and more hospitals are installing digital, `filmless' radiology (and other imagery) systems. They generate a staggering amount of information around the clock. For example, a typical 500-bed hospital might accumulate more than 5 terabytes of image data in a period of 30 years for conventional x-ray images and digital images such as Magnetic Resonance Imaging and Computer Tomography images. With several hospitals contributing to the archive, the storage required will be in the hundreds of terabytes. Systems for reliable, secure, and inexpensive storage and retrieval of digital medical information do not exist today. In this paper, we present a Medical Image Archive and Distribution Service (MIADS) concept. MIADS is a system shared by individual and community hospitals, laboratories, and doctors' offices that need to store and retrieve medical images. Due to the large volume and complexity of the data, as well as the diversified user access requirement, implementation of the MIADS will be a complex procedure. One of the key challenges to implementing a MIADS is to select a cost-effective, scalable system architecture to meet the ingest/retrieval performance requirements. We have performed an in-depth system engineering study, and developed a sophisticated simulation model to address this key challenge. This paper describes the overall system architecture based on our system engineering study and simulation results. In particular, we will emphasize system scalability and upgradability issues. Furthermore, we will discuss our simulation results in detail. The simulations study the ingest/retrieval performance requirements based on different system configurations and architectures for variables such as workload, tape

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

    PubMed

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

    2015-01-01

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

  13. CT imaging of the internal human ear: Test of a high resolution scanner

    NASA Astrophysics Data System (ADS)

    Bettuzzi, M.; Brancaccio, R.; Morigi, M. P.; Gallo, A.; Strolin, S.; Casali, F.; Lamanna, Ernesto; Ariù, Marilù

    2011-08-01

    During the course of 2009, in the framework of a project supported by the National Institute of Nuclear Physics, a number of tests were carried out at the Department of Physics of the University of Bologna in order to achieve a good quality CT scan of the internal human ear. The work was carried out in collaboration with the local “S. Orsola” Hospital in Bologna and a company (CEFLA) already involved in the production and commercialization of a CT scanner dedicated to dentistry. A laboratory scanner with a simple concept detector (CCD camera-lens-mirror-scintillator) was used to see to what extent it was possible to enhance the quality of a conventional CT scanner when examining the internal human ear. To test the system, some conventional measurements were made, such as the spatial resolution calculation with the MTF and dynamic range evaluation. Different scintillators were compared to select the most suitable for the purpose. With 0.5 mm thick structured cesium iodide and a field of view of 120×120 mm2, a spatial resolution of 6.5l p/mm at 5% MTF was obtained. The CT of a pair of human head phantoms was performed at an energy of 120 kVp. The first phantom was a rough representation of the human head shape, with soft tissue made of coarse slabs of Lucite. Some inserts, like small aluminum cylinders and cubes, with 1 mm diameter drilled holes, were used to simulate the channels that one finds inside the human inner ear. The second phantom is a plastic PVC fused head with a real human cranium inside. The bones in the cranium are well conserved and the inner ear features, such as the cochlea and semicircular channels, are clearly detectable. After a number of CT tests we obtained good results as far as structural representation and channel detection are concerned. Some images of the 3D rendering of the CT volume are shown below. The doctors of the local hospital who followed our experimentation expressed their satisfaction. The CT was compared to a virtual

  14. Simultaneous reconstruction of the activity image and registration of the CT image in TOF-PET

    NASA Astrophysics Data System (ADS)

    Rezaei, Ahmadreza; Michel, Christian; Casey, Michael E.; Nuyts, Johan

    2016-02-01

    Previously, maximum-likelihood methods have been proposed to jointly estimate the activity image and the attenuation image or the attenuation sinogram from time-of-flight (TOF) positron emission tomography (PET) data. In this contribution, we propose a method that addresses the possible alignment problem of the TOF-PET emission data and the computed tomography (CT) attenuation data, by combining reconstruction and registration. The method, called MLRR, iteratively reconstructs the activity image while registering the available CT-based attenuation image, so that the pair of activity and attenuation images maximise the likelihood of the TOF emission sinogram. The algorithm is slow to converge, but some acceleration could be achieved by using Nesterov’s momentum method and by applying a multi-resolution scheme for the non-rigid displacement estimation. The latter also helps to avoid local optima, although convergence to the global optimum cannot be guaranteed. The results are evaluated on 2D and 3D simulations as well as a respiratory gated clinical scan. Our experiments indicate that the proposed method is able to correct for possible misalignment of the CT-based attenuation image, and is therefore a very promising approach to suppressing attenuation artefacts in clinical PET/CT. When applied to respiratory gated data of a patient scan, it produced deformations that are compatible with breathing motion and which reduced the well known attenuation artefact near the dome of the liver. Since the method makes use of the energy-converted CT attenuation image, the scale problem of joint reconstruction is automatically solved.

  15. Fingerprint verification on medical image reporting system.

    PubMed

    Chen, Yen-Cheng; Chen, Liang-Kuang; Tsai, Ming-Dar; Chiu, Hou-Chang; Chiu, Jainn-Shiun; Chong, Chee-Fah

    2008-03-01

    The healthcare industry is recently going through extensive changes, through adoption of robust, interoperable healthcare information technology by means of electronic medical records (EMR). However, a major concern of EMR is adequate confidentiality of the individual records being managed electronically. Multiple access points over an open network like the Internet increases possible patient data interception. The obligation is on healthcare providers to procure information security solutions that do not hamper patient care while still providing the confidentiality of patient information. Medical images are also part of the EMR which need to be protected from unauthorized users. This study integrates the techniques of fingerprint verification, DICOM object, digital signature and digital envelope in order to ensure that access to the hospital Picture Archiving and Communication System (PACS) or radiology information system (RIS) is only by certified parties. PMID:18178287

  16. Scalar-vector quantization of medical images.

    PubMed

    Mohsenian, N; Shahri, H; Nasrabadi, N M

    1996-01-01

    A new coding scheme based on the scalar-vector quantizer (SVQ) is developed for compression of medical images. The SVQ is a fixed rate encoder and its rate-distortion performance is close to that of optimal entropy-constrained scalar quantizers (ECSQs) for memoryless sources. The use of a fixed-rate quantizer is expected to eliminate some of the complexity of using variable-length scalar quantizers. When transmission of images over noisy channels is considered, our coding scheme does not suffer from error propagation that is typical of coding schemes using variable-length codes. For a set of magnetic resonance (MR) images, coding results obtained from SVQ and ECSQ at low bit rates are indistinguishable. Furthermore, our encoded images are perceptually indistinguishable from the original when displayed on a monitor. This makes our SVQ-based coder an attractive compression scheme for picture archiving and communication systems (PACS). PACS are currently under study for use in an all-digital radiology environment in hospitals, where reliable transmission, storage, and high fidelity reconstruction of images are desired. PMID:18285124

  17. A software tool for automatic classification and segmentation of 2D/3D medical images

    NASA Astrophysics Data System (ADS)

    Strzelecki, Michal; Szczypinski, Piotr; Materka, Andrzej; Klepaczko, Artur

    2013-02-01

    Modern medical diagnosis utilizes techniques of visualization of human internal organs (CT, MRI) or of its metabolism (PET). However, evaluation of acquired images made by human experts is usually subjective and qualitative only. Quantitative analysis of MR data, including tissue classification and segmentation, is necessary to perform e.g. attenuation compensation, motion detection, and correction of partial volume effect in PET images, acquired with PET/MR scanners. This article presents briefly a MaZda software package, which supports 2D and 3D medical image analysis aiming at quantification of image texture. MaZda implements procedures for evaluation, selection and extraction of highly discriminative texture attributes combined with various classification, visualization and segmentation tools. Examples of MaZda application in medical studies are also provided.

  18. Incomplete-data CT image reconstructions in industrial applications

    NASA Astrophysics Data System (ADS)

    Tam, K. C.; Eberhard, J. W.; Mitchell, K. W.

    1990-06-01

    In industrial X-ray computerized tomography (CT), the objects to be inspected are usually very attenuating to X-rays, and their shape may not permit complete scannings at all view angles; incomplete-data imaging situations usually result. Image reconstruction from incomplete data can be achieved through an iterative transform algorithm, which utilizes the a priori information on the object to compensate for the missing data. The results of validating the iterative transform algorithm on experimental data from a cross section of a high-pressure turbine blade made of Ni-based superalloy are reported. From the data set, two kinds of incomplete data situations are simulated: incomplete projection and limited-angle scanning. The results indicate that substantial improvements, both visually and in wall thickness measurements, were brought about in all cases through the use of the iterative transform algorithm.

  19. Task-based optimization of image reconstruction in breast CT

    NASA Astrophysics Data System (ADS)

    Sanchez, Adrian A.; Sidky, Emil Y.; Pan, Xiaochuan

    2014-03-01

    We demonstrate a task-based assessment of image quality in dedicated breast CT in order to optimize the number of projection views acquired. The methodology we employ is based on the Hotelling Observer (HO) and its associated metrics. We consider two tasks: the Rayleigh task of discerning between two resolvable objects and a single larger object, and the signal detection task of classifying an image as belonging to either a signalpresent or signal-absent hypothesis. HO SNR values are computed for 50, 100, 200, 500, and 1000 projection view images, with the total imaging radiation dose held constant. We use the conventional fan-beam FBP algorithm and investigate the effect of varying the width of a Hanning window used in the reconstruction, since this affects both the noise properties of the image and the under-sampling artifacts which can arise in the case of sparse-view acquisitions. Our results demonstrate that fewer projection views should be used in order to increase HO performance, which in this case constitutes an upper-bound on human observer performance. However, the impact on HO SNR of using fewer projection views, each with a higher dose, is not as significant as the impact of employing regularization in the FBP reconstruction through a Hanning filter.

  20. Parametric dynamic F-18-FDG PET/CT breast imaging

    NASA Astrophysics Data System (ADS)

    Magri, Alphonso; Feiglin, David; Lipson, Edward; Mandel, James; McGraw, Wendy; Lee, Wei; Krol, Andrzej

    2008-03-01

    This study was undertaken to estimate metabolic tissue properties from dynamic breast F-18-FDG PET/CT image series and to display them as 3D parametric images. Each temporal PET series was obtained immediately after injection of 10 mCi of F-18-FDG and consisted of fifty 1- minute frames. Each consecutive frame was nonrigidly registered to the first frame using a finite element method (FEM) based model and fiducial skin markers. Nonlinear curve fitting of activity vs. time based on a realistic two-compartment model was performed for each voxel of the volume. Curve fitting was accomplished by application of the Levenburg-Marquardt algorithm (LMA) that minimized X2. We evaluated which parameters are most suitable to determine the spatial extent and malignancy in suspicious lesions. In addition, Patlak modeling was applied to the data. A mixture model was constructed and provided a classification system for the breast tissue. It produced unbiased estimation of the spatial extent of the lesions. We conclude that nonrigid registration followed by voxel-by-voxel based nonlinear fitting to a realistic two-compartment model yields better quality parametric images, as compared to unprocessed dynamic breast PET time series. By comparison with the mixture model, we established that the total cumulated activity and maximum activity parametric images provide the best delineation of suspicious breast tissue lesions and hyperactive subregions within the lesion that cannot be discerned in unprocessed images.

  1. SPECT-CT system for small animal imaging

    SciTech Connect

    Andrew Weisenberger; Randolph Wojcik; E.L. Bradley; Paul Brewer; Stanislaw Majewski; Jianguo Qian; Amoreena Ranck; Arunava Saha; Mark Smith; Robert Welsh

    2003-02-01

    The Detector Group at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) and the Biology, Physics, and Applied Sciences Departments at the College of William and Mary are collaborating on the development of a miniature dual modality SPECT-CT system for mouse imaging. The detector heads of the SPECT sub-system are designed to be capable of imaging the gamma- and X-ray emissions (28-35 keV) of the radioactive isotope iodine-125 (I-125). Two different sets of I-125 imaging detectors are configured on a gantry that has an open-barrel type design. One set of detector heads is based on the 1-in square Hamamatsu R5900-M64 position sensitive photomultiplier tube coupled to crystal scintillator arrays. The other detector heads configured on the gantry are two 5-in diameter Hamamatsu R3292-based compact gamma cameras. The X-ray radiographic projections are obtained using a LIXI Inc. model LF-85-503-OS X-ray imaging system that has an active area of 5.5 cm in diameter. The open-barrel shaped gantry facilitates the positioning of various mini gamma-ray imaging detectors and the X-ray system. The data acquisition and gantry control is interfaced through a Macintosh G3 workstation. Preliminary SPECT reconstruction results using the R5900 based detector are presented.

  2. SPECT-CT System for Small Animal Imaging

    SciTech Connect

    A.G. Weisenberger; R. Wojcik; E.L. Bradley; P. Brewer; S. Majewski; J. Qian; A. Ranck; M.S. Saha; K. Smith; M.F. Smith; R.E. Welsh

    2001-11-01

    The Detector Group at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) and the Biology, Physics and Applied Sciences Departments at the College of William and Mary are collaborating on the development of a miniature dual modality SPECT-CT system for mouse imaging. The detector heads of the SPECT sub-system are capable of imaging the gamma- and x-ray emissions (28-35 keV) of the radioactive isotope iodine-125 (I-125). Two different sets of I-125 imaging detectors are configured on a gantry which has an open-barrel type design. One set of detector heads is based on the 1 inch square Hamamatsu R5900-M64 position sensitive photomultiplier tube coupled to crystal scintillator arrays. The other detector heads configured on the gantry are two 5-inch diameter Hamamatsu R3292-based compact gamma cameras. The x-ray radiographic projections will be obtained using a LIXI Inc. model LF-85-503-OS x-ray imaging system that has an active area of 5.5 cm in diameter. The open-barrel shaped gantry facilitates the positioning of various mini gamma-ray imaging detectors and the x-ray system. The data acquisition and gantry control is interfaced through a Macintosh G3 workstation. SPECT reconstruction results using the R5900 based detector are presented.

  3. Novel multi-beam X-ray source for vacuum electronics enabled medical imaging applications

    NASA Astrophysics Data System (ADS)

    Neculaes, V. Bogdan

    2013-10-01

    For almost 100 of years, commercial medical X-ray applications have relied heavily on X-ray tube architectures based on the vacuum electronics design developed by William Coolidge at the beginning of the twentieth century. Typically, the Coolidge design employs one hot tungsten filament as the electron source; the output of the tube is one X-ray beam. This X-ray source architecture is the state of the art in today's commercial medical imaging applications, such as Computed Tomography. Recently, GE Global Research has demonstrated the most dramatic extension of the Coolidge vacuum tube design for Computed Tomography (CT) in almost a century: a multi-beam X-ray source containing thirty two cathodes emitting up to 1000 mA, in a cathode grounded - anode at potential architecture (anode up to 140 kV). This talk will present the challenges of the X-ray multi-beam vacuum source design - space charge electron gun design, beam focusing to compression ratios needed in CT medical imaging applications (image resolution is critically dependent on how well the electron beam is focused in vacuum X-ray tubes), electron emitter choice to fit the aggressive beam current requirements, novel electronics for beam control and focusing, high voltage and vacuum solutions, as well as vacuum chamber design to sustain the considerable G forces typically encountered on a CT gantry (an X-ray vacuum tube typically rotates on the CT gantry at less than 0.5 s per revolution). Consideration will be given to various electron emitter technologies available for this application - tungsten emitters, dispenser cathodes and carbon nano tubes (CNT) - and their tradeoffs. The medical benefits potentially enabled by this unique vacuum multi-beam X-ray source are: X-ray dose reduction, reduction of image artifacts and improved image resolution. This work was funded in part by NIH grant R01EB006837.

  4. Machine learning for medical images analysis.

    PubMed

    Criminisi, A

    2016-10-01

    This article discusses the application of machine learning for the analysis of medical images. Specifically: (i) We show how a special type of learning models can be thought of as automatically optimized, hierarchically-structured, rule-based algorithms, and (ii) We discuss how the issue of collecting large labelled datasets applies to both conventional algorithms as well as machine learning techniques. The size of the training database is a function of model complexity rather than a characteristic of machine learning methods. PMID:27374127

  5. Integrated wavelets for medical image analysis

    NASA Astrophysics Data System (ADS)

    Heinlein, Peter; Schneider, Wilfried

    2003-11-01

    Integrated wavelets are a new method for discretizing the continuous wavelet transform (CWT). Independent of the choice of discrete scale and orientation parameters they yield tight families of convolution operators. Thus these families can easily be adapted to specific problems. After presenting the fundamental ideas, we focus primarily on the construction of directional integrated wavelets and their application to medical images. We state an exact algorithm for implementing this transform and present applications from the field of digital mammography. The first application covers the enhancement of microcalcifications in digital mammograms. Further, we exploit the directional information provided by integrated wavelets for better separation of microcalcifications from similar structures.

  6. Cerenkov luminescence imaging of medical isotopes

    PubMed Central

    Ruggiero, Alessandro; Holland, Jason P.; Lewis, Jason S.; Grimm, Jan

    2011-01-01

    The development of novel multimodality imaging agents and techniques represents the current frontier of research in the field of medical imaging science. However, the combination of nuclear tomography with optical techniques has yet to be established. Here, we report the use of the inherent optical emissions from the decay of radiopharmaceuticals for Cerenkov luminescence imaging (CLI) of tumors in vivo and correlate the results with those obtained from concordant immuno-PET studies. Methods In vitro phantom studies were used to validate the visible light emission observed from a range of radionuclides including the positron emitters 18F, 64Cu, 89Zr, and 124I; β-emitter 131I; and α-particle emitter 225Ac for potential use in CLI. The novel radiolabeled monoclonal antibody 89Zr-desferrioxamine B-[DFO-J591 for immuno-PET of prostate-specific membrane antigen (PSMA) expression was used to coregister and correlate the CLI signal observed with the immuno-PET images and biodistribution studies. Results Phantom studies confirmed that Cerenkov radiation can be observed from a range of positron-,β-, and α-emitting radionuclides using standard optical imaging devices. The change in light emission intensity versus time was concordant with radionuclide decay and was also found to correlate linearly with both the activity concentration and the measured PET signal (percentage injected dose per gram). In vivo studies conducted in male severe combined immune deficient mice bearing PSMA-positive, subcutaneous LNCaP tumors demonstrated that tumor-specific uptake of 89Zr-DFO-J591 could be visualized by both immuno-PET and CLI. Optical and immuno-PET signal intensities were found to increase over time from 24 to 96 h, and biodistribution studies were found to correlate well with both imaging modalities. Conclusion These studies represent the first, to our knowledge, quantitative assessment of CLI for measuring radiotracer uptake in vivo. Many radionuclides common to both nuclear

  7. CT image construction of a totally deflated lung using deformable model extrapolation

    SciTech Connect

    Sadeghi Naini, Ali; Pierce, Greg; Lee, Ting-Yim; and others

    2011-02-15

    Purpose: A novel technique is proposed to construct CT image of a totally deflated lung from a free-breathing 4D-CT image sequence acquired preoperatively. Such a constructed CT image is very useful in performing tumor ablative procedures such as lung brachytherapy. Tumor ablative procedures are frequently performed while the lung is totally deflated. Deflating the lung during such procedures renders preoperative images ineffective for targeting the tumor. Furthermore, the problem cannot be solved using intraoperative ultrasound (U.S.) images because U.S. images are very sensitive to small residual amount of air remaining in the deflated lung. One possible solution to address these issues is to register high quality preoperative CT images of the deflated lung with their corresponding low quality intraoperative U.S. images. However, given that such preoperative images correspond to an inflated lung, such CT images need to be processed to construct CT images pertaining to the lung's deflated state. Methods: To obtain the CT images of deflated lung, we present a novel image construction technique using extrapolated deformable registration to predict the deformation the lung undergoes during full deflation. The proposed construction technique involves estimating the lung's air volume in each preoperative image automatically in order to track the respiration phase of each 4D-CT image throughout a respiratory cycle; i.e., the technique does not need any external marker to form a respiratory signal in the process of curve fitting and extrapolation. The extrapolated deformation field is then applied on a preoperative reference image in order to construct the totally deflated lung's CT image. The technique was evaluated experimentally using ex vivo porcine lung. Results: The ex vivo lung experiments led to very encouraging results. In comparison with the CT image of the deflated lung we acquired for the purpose of validation, the constructed CT image was very similar. The

  8. Automated Movement Correction for Dynamic PET/CT Images: Evaluation with Phantom and Patient Data

    PubMed Central

    Ye, Hu; Wong, Koon-Pong; Wardak, Mirwais; Dahlbom, Magnus; Kepe, Vladimir; Barrio, Jorge R.; Nelson, Linda D.; Small, Gary W.; Huang, Sung-Cheng

    2014-01-01

    Head movement during a dynamic brain PET/CT imaging results in mismatch between CT and dynamic PET images. It can cause artifacts in CT-based attenuation corrected PET images, thus affecting both the qualitative and quantitative aspects of the dynamic PET images and the derived parametric images. In this study, we developed an automated retrospective image-based movement correction (MC) procedure. The MC method first registered the CT image to each dynamic PET frames, then re-reconstructed the PET frames with CT-based attenuation correction, and finally re-aligned all the PET frames to the same position. We evaluated the MC method's performance on the Hoffman phantom and dynamic FDDNP and FDG PET/CT images of patients with neurodegenerative disease or with poor compliance. Dynamic FDDNP PET/CT images (65 min) were obtained from 12 patients and dynamic FDG PET/CT images (60 min) were obtained from 6 patients. Logan analysis with cerebellum as the reference region was used to generate regional distribution volume ratio (DVR) for FDDNP scan before and after MC. For FDG studies, the image derived input function was used to generate parametric image of FDG uptake constant (Ki) before and after MC. Phantom study showed high accuracy of registration between PET and CT and improved PET images after MC. In patient study, head movement was observed in all subjects, especially in late PET frames with an average displacement of 6.92 mm. The z-direction translation (average maximum = 5.32 mm) and x-axis rotation (average maximum = 5.19 degrees) occurred most frequently. Image artifacts were significantly diminished after MC. There were significant differences (P<0.05) in the FDDNP DVR and FDG Ki values in the parietal and temporal regions after MC. In conclusion, MC applied to dynamic brain FDDNP and FDG PET/CT scans could improve the qualitative and quantitative aspects of images of both tracers. PMID:25111700

  9. Realistic simulation of reduced-dose CT with noise modeling and sinogram synthesis using DICOM CT images

    SciTech Connect

    Won Kim, Chang; Kim, Jong Hyo

    2014-01-15

    Purpose: Reducing the patient dose while maintaining the diagnostic image quality during CT exams is the subject of a growing number of studies, in which simulations of reduced-dose CT with patient data have been used as an effective technique when exploring the potential of various dose reduction techniques. Difficulties in accessing raw sinogram data, however, have restricted the use of this technique to a limited number of institutions. Here, we present a novel reduced-dose CT simulation technique which provides realistic low-dose images without the requirement of raw sinogram data. Methods: Two key characteristics of CT systems, the noise equivalent quanta (NEQ) and the algorithmic modulation transfer function (MTF), were measured for various combinations of object attenuation and tube currents by analyzing the noise power spectrum (NPS) of CT images obtained with a set of phantoms. Those measurements were used to develop a comprehensive CT noise model covering the reduced x-ray photon flux, object attenuation, system noise, and bow-tie filter, which was then employed to generate a simulated noise sinogram for the reduced-dose condition with the use of a synthetic sinogram generated from a reference CT image. The simulated noise sinogram was filtered with the algorithmic MTF and back-projected to create a noise CT image, which was then added to the reference CT image, finally providing a simulated reduced-dose CT image. The simulation performance was evaluated in terms of the degree of NPS similarity, the noise magnitude, the bow-tie filter effect, and the streak noise pattern at photon starvation sites with the set of phantom images. Results: The simulation results showed good agreement with actual low-dose CT images in terms of their visual appearance and in a quantitative evaluation test. The magnitude and shape of the NPS curves of the simulated low-dose images agreed well with those of real low-dose images, showing discrepancies of less than +/−3.2% in

  10. Viewpoints on Medical Image Processing: From Science to Application

    PubMed Central

    Deserno (né Lehmann), Thomas M.; Handels, Heinz; Maier-Hein (né Fritzsche), Klaus H.; Mersmann, Sven; Palm, Christoph; Tolxdorff, Thomas; Wagenknecht, Gudrun; Wittenberg, Thomas

    2013-01-01

    Medical image processing provides core innovation for medical imaging. This paper is focused on recent developments from science to applications analyzing the past fifteen years of history of the proceedings of the German annual meeting on medical image processing (BVM). Furthermore, some members of the program committee present their personal points of views: (i) multi-modality for imaging and diagnosis, (ii) analysis of diffusion-weighted imaging, (iii) model-based image analysis, (iv) registration of section images, (v) from images to information in digital endoscopy, and (vi) virtual reality and robotics. Medical imaging and medical image computing is seen as field of rapid development with clear trends to integrated applications in diagnostics, treatment planning and treatment. PMID:24078804

  11. Improving Image Quality of Bronchial Arteries with Virtual Monochromatic Spectral CT Images

    PubMed Central

    Ma, Guangming; He, Taiping; Yu, Yong; Duan, Haifeng; Yang, Chuangbo

    2016-01-01

    Objective To evaluate the clinical value of using monochromatic images in spectral CT pulmonary angiography to improve image quality of bronchial arteries. Methods We retrospectively analyzed the chest CT images of 38 patients who underwent contrast-enhanced spectral CT. These images included a set of 140kVp polychromatic images and the default 70keV monochromatic images. Using the standard Gemstone Spectral Imaging (GSI) viewer on an advanced workstation (AW4.6,GE Healthcare), an optimal energy level (in keV) for obtaining the best contrast-to-noise ratio (CNR) for the artery could be automatically obtained. The signal-to-noise ratio (SNR), CNR and objective image quality score (1–5) for these 3 image sets (140kVp, 70keV and optimal energy level) were obtained and, statistically compared. The image quality score consistency between the two observers was also evaluated using Kappa test. Results The optimal energy levels for obtaining the best CNR were 62.58±2.74keV.SNR and CNR from the 140kVp polychromatic, 70keV and optimal keV monochromatic images were (16.44±5.85, 13.24±5.52), (20.79±7.45, 16.69±6.27) and (24.9±9.91, 20.53±8.46), respectively. The corresponding subjective image quality scores were 1.97±0.82, 3.24±0.75, and 4.47±0.60. SNR, CNR and subjective scores had significant difference among groups (all p<0.001). The optimal keV monochromatic images were superior to the 70keV monochromatic and 140kVp polychromatic images, and there was high agreement between the two observers on image quality score (kappa>0.80). Conclusions Virtual monochromatic images at approximately 63keV in dual-energy spectral CT pulmonary angiography yielded the best CNR and highest diagnostic confidence for imaging bronchial arteries. PMID:26967737

  12. Gemstone spectral imaging: determination of CT to ED conversion curves for radiotherapy treatment planning.

    PubMed

    Yagi, Masashi; Ueguchi, Takashi; Koizumi, Masahiko; Ogata, Toshiyuki; Yamada, Sachiko; Takahashi, Yutaka; Sumida, Iori; Akino, Yuichi; Konishi, Koji; Isohashi, Fumiaki; Tomiyama, Noriyuki; Yoshioka, Yasuo; Ogawa, Kazuhiko

    2013-01-01

    The monochromatic images acquired by Gemstone spectral imaging (GSI) mode on the GE CT750 HD theoretically determines the computed tomography (CT) number more accurately than that of conventional scanner. Using the former, the CT number is calculated from (synthesized) monoenergetic X-ray data. We reasoned that the monochromatic image might be applied to radiotherapy treatment planning (RTP) to calculate dose distribution more accurately. Our goal here was to provide CT to electron density (ED) conversion curves with monochromatic images for RTP. Therefore, we assessed the reproducibility of CT numbers, an important factor on quality assurance, over short and long time periods for different substances at varying energy. CT number difference between measured and theoretical value was investigated. The scanner provided sufficient reproducibility of CT numbers for dose calculation over short and long time periods. The CT numbers of monochromatic images produced by this scanner had reasonable values for dose calculation. The CT to ED conversion curve becomes linear with respect to the relationship between CT numbers and EDs as the energy increases. We conclude that monochromatic imaging from a fast switching system can be applied for the dose calculation, keeping Hounsfield units (HU) stability. PMID:24036870

  13. SU-E-I-73: Clinical Evaluation of CT Image Reconstructed Using Interior Tomography

    SciTech Connect

    Zhang, J; Ge, G; Winkler, M; Cong, W; Wang, G

    2014-06-01

    Purpose: Radiation dose reduction has been a long standing challenge in CT imaging of obese patients. Recent advances in interior tomography (reconstruction of an interior region of interest (ROI) from line integrals associated with only paths through the ROI) promise to achieve significant radiation dose reduction without compromising image quality. This study is to investigate the application of this technique in CT imaging through evaluating imaging quality reconstructed from patient data. Methods: Projection data were directly obtained from patients who had CT examinations in a Dual Source CT scanner (DSCT). Two detectors in a DSCT acquired projection data simultaneously. One detector provided projection data for full field of view (FOV, 50 cm) while another detectors provided truncated projection data for a FOV of 26 cm. Full FOV CT images were reconstructed using both filtered back projection and iterative algorithm; while interior tomography algorithm was implemented to reconstruct ROI images. For comparison reason, FBP was also used to reconstruct ROI images. Reconstructed CT images were evaluated by radiologists and compared with images from CT scanner. Results: The results show that the reconstructed ROI image was in excellent agreement with the truth inside the ROI, obtained from images from CT scanner, and the detailed features in the ROI were quantitatively accurate. Radiologists evaluation shows that CT images reconstructed with interior tomography met diagnosis requirements. Radiation dose may be reduced up to 50% using interior tomography, depending on patient size. Conclusion: This study shows that interior tomography can be readily employed in CT imaging for radiation dose reduction. It may be especially useful in imaging obese patients, whose subcutaneous tissue is less clinically relevant but may significantly increase radiation dose.

  14. Iterative Image Reconstruction for Limited-Angle CT Using Optimized Initial Image

    PubMed Central

    Guo, Jingyu; Qi, Hongliang; Xu, Yuan; Chen, Zijia; Li, Shulong; Zhou, Linghong

    2016-01-01

    Limited-angle computed tomography (CT) has great impact in some clinical applications. Existing iterative reconstruction algorithms could not reconstruct high-quality images, leading to severe artifacts nearby edges. Optimal selection of initial image would influence the iterative reconstruction performance but has not been studied deeply yet. In this work, we proposed to generate optimized initial image followed by total variation (TV) based iterative reconstruction considering the feature of image symmetry. The simulated data and real data reconstruction results indicate that the proposed method effectively removes the artifacts nearby edges. PMID:27066107

  15. High-accuracy registration of intraoperative CT imaging

    NASA Astrophysics Data System (ADS)

    Oentoro, A.; Ellis, R. E.

    2010-02-01

    Image-guided interventions using intraoperative 3D imaging can be less cumbersome than systems dependent on preoperative images, especially by needing neither potentially invasive image-to-patient registration nor a lengthy process of segmenting and generating a 3D surface model. In this study, a method for computer-assisted surgery using direct navigation on intraoperative imaging is presented. In this system the registration step of a navigated procedure was divided into two stages: preoperative calibration of images to a ceiling-mounted optical tracking system, and intraoperative tracking during acquisition of the 3D medical image volume. The preoperative stage used a custom-made multi-modal calibrator that could be optically tracked and also contained fiducial spheres for radiological detection; a robust registration algorithm was used to compensate for the very high false-detection rate that was due to the high physical density of the optical light-emitting diodes. Intraoperatively, a tracking device was attached to plastic bone models that were also instrumented with radio-opaque spheres; A calibrated pointer was used to contact the latter spheres as a validation of the registration. Experiments showed that the fiducial registration error of the preoperative calibration stage was approximately 0.1 mm. The target registration error in the validation stage was approximately 1.2 mm. This study suggests that direct registration, coupled with procedure-specific graphical rendering, is potentially a highly accurate means of performing image-guided interventions in a fast, simple manner.

  16. Watermarked cardiac CT image segmentation using deformable models and the Hermite transform

    NASA Astrophysics Data System (ADS)

    Gomez-Coronel, Sandra L.; Moya-Albor, Ernesto; Escalante-Ramírez, Boris; Brieva, Jorge

    2015-01-01

    Medical image watermarking is an open area for research and is a solution for the protection of copyright and intellectual property. One of the main challenges of this problem is that the marked images should not differ perceptually from the original images allowing a correct diagnosis and authentication. Furthermore, we also aim at obtaining watermarked images with very little numerical distortion so that computer vision tasks such as segmentation of important anatomical structures do not be impaired or affected. We propose a preliminary watermarking application in cardiac CT images based on a perceptive approach that includes a brightness model to generate a perceptive mask and identify the image regions where the watermark detection becomes a difficult task for the human eye. We propose a normalization scheme of the image in order to improve robustness against geometric attacks. We follow a spread spectrum technique to insert an alphanumeric code, such as patient's information, within the watermark. The watermark scheme is based on the Hermite transform as a bio-inspired image representation model. In order to evaluate the numerical integrity of the image data after watermarking, we perform a segmentation task based on deformable models. The segmentation technique is based on a vector-value level sets method such that, given a curve in a specific image, and subject to some constraints, the curve can evolve in order to detect objects. In order to stimulate the curve evolution we introduce simultaneously some image features like the gray level and the steered Hermite coefficients as texture descriptors. Segmentation performance was assessed by means of the Dice index and the Hausdorff distance. We tested different mark sizes and different insertion schemes on images that were later segmented either automatic or manual by physicians.

  17. A comparison of four algorithms for metal artifact reduction in CT imaging

    NASA Astrophysics Data System (ADS)

    Golden, Caroline; Mazin, Samuel R.; Boas, F. Edward; Tye, Grace; Ghanouni, Pejman; Gold, Garry; Sofilos, Marc; Pelc, Norbert J.

    2011-03-01

    Streak artifacts caused by the presence of metal have been a significant problem in CT imaging since its inception in 1972. With the fast evolving medical device industry, the number of metal objects implanted in patients is increasing annually. This correlates directly with an increased likelihood of encountering metal in a patient CT scan, thus necessitating the need for an effective and reproducible metal artifact reduction (MAR) algorithm. Previous comparisons between MAR algorithms have typically only evaluated a small number of patients and a limited range of metal implants. Although the results of many methods are promising, the reproducibility of these results is key to providing more tangible evidence of their effectiveness. This study presents a direct comparison between the performances, assessed by board certified radiologists, of four MAR algorithms: 3 non-iterative and one iterative method, all applied and compared to the original clinical images. The results of the evaluation indicated a negative mean score in almost all uses for two of the non-iterative methods, signifying an overall decrease in the diagnostic quality of the images, generally due to perceived loss of detail. One non-iterative algorithm showed a slight improvement. The iterative algorithm was superior in all studies by producing a considerable improvement in all uses.

  18. 3D segmentation of the true and false lumens on CT aortic dissection images

    NASA Astrophysics Data System (ADS)

    Fetnaci, Nawel; Łubniewski, Paweł; Miguel, Bruno; Lohou, Christophe

    2013-03-01

    Our works are related to aortic dissections which are a medical emergency and can quickly lead to death. In this paper, we want to retrieve in CT images the false and the true lumens which are aortic dissection features. Our aim is to provide a 3D view of the lumens that we can difficultly obtain either by volume rendering or by another visualization tool which only directly gives the outer contour of the aorta; or by other segmentation methods because they mainly directly segment either only the outer contour of the aorta or other connected arteries and organs both. In our work, we need to segment the two lumens separately; this segmentation will allow us to: distinguish them automatically, facilitate the landing of the aortic prosthesis, propose a virtual 3d navigation and do quantitative analysis. We chose to segment these data by using a deformable model based on the fast marching method. In the classical fast marching approach, a speed function is used to control the front propagation of a deforming curve. The speed function is only based on the image gradient. In our CT images, due to the low resolution, with the fast marching the front propagates from a lumen to the other; therefore, the gradient data is insufficient to have accurate segmentation results. In the paper, we have adapted the fast marching method more particularly by modifying the speed function and we succeed in segmenting the two lumens separately.

  19. High-Pitch CT Pulmonary Angiography in Third Generation Dual-Source CT: Image Quality in an Unselected Patient Population

    PubMed Central

    Sabel, Bastian O.; Buric, Kristijan; Karara, Nora; Thierfelder, Kolja M.; Dinkel, Julien; Sommer, Wieland H.; Meinel, Felix G.

    2016-01-01

    Objectives To investigate the feasibility of high-pitch CT pulmonary angiography (CTPA) in 3rd generation dual-source CT (DSCT) in unselected patients. Methods Forty-seven patients with suspected pulmonary embolism underwent high-pitch CTPA on a 3rd generation dual-source CT scanner. CT dose index (CTDIvol) and dose length product (DLP) were obtained. Objective image quality was analyzed by calculating signal-to-noise-ratio (SNR) and contrast-to-noise ratio (CNR). Subjective image quality on the central, lobar, segmental and subsegmental level was rated by two experienced radiologists. Results Median CTDI was 8.1 mGy and median DLP was 274 mGy*cm. Median SNR was 32.9 in the central and 31.9 in the segmental pulmonary arteries. CNR was 29.2 in the central and 28.2 in the segmental pulmonary arteries. Median image quality was “excellent” in central and lobar arteries and “good” in subsegmental arteries according to both readers. Segmental arteries varied between “excellent” and “good”. Image quality was non-diagnostic in one case (2%), beginning in the lobar arteries. Thirteen patients (28%) showed minor motion artifacts. Conclusions In third-generation dual-source CT, high-pitch CTPA is feasible for unselected patients. It yields excellent image quality with minimal motion artifacts. However, compared to standard-pitch cohorts, no distinct decrease in radiation dose was observed. PMID:26872262

  20. Electronics Signal Processing for Medical Imaging

    NASA Astrophysics Data System (ADS)

    Turchetta, Renato

    This paper describes the way the signal coming from a radiation detector is conditioned and processed to produce images useful for medical applications. First of all, the small signal produce by the radiation is processed by analogue electronics specifically designed to produce a good signal-over-noise ratio. The optimised analogue signal produced at this stage can then be processed and transformed into digital information that is eventually stored in a computer, where it can be further processed as required. After an introduction to the general requirements of the processing electronics, we will review the basic building blocks that process the `tiny' analogue signal coming from a radiation detector. We will in particular analyse how it is possible to optimise the signal-over-noise ratio of the electronics. Some exercises, developed in the tutorial, will help to understand this fundamental part. The blocks needed to process the analogue signal and transform it into a digital code will be described. The description of electronics systems used for medical imaging systems will conclude the lecture.

  1. Incorporating multislice imaging into x-ray CT polymer gel dosimetry

    SciTech Connect

    Johnston, H.; Hilts, M.; Jirasek, A.

    2015-04-15

    Purpose: To evaluate multislice computed tomography (CT) scanning for fast and reliable readout of radiation therapy (RT) dose distributions using CT polymer gel dosimetry (PGD) and to establish a baseline assessment of image noise and uniformity in an unirradiated gel dosimeter. Methods: A 16-slice CT scanner was used to acquire images through a 1 L cylinder filled with water. Additional images were collected using a single slice machine. The variability in CT number (N{sub CT}) associated with the anode heel effect was evaluated and used to define a new slice-by-slice background subtraction artifact removal technique for CT PGD. Image quality was assessed for the multislice system by evaluating image noise and uniformity. The agreement in N{sub CT} for slices acquired simultaneously using the multislice detector array was also examined. Further study was performed to assess the effects of increasing x-ray tube load on the constancy of measured N{sub CT} and overall scan time. In all cases, results were compared to the single slice machine. Finally, images were collected throughout the volume of an unirradiated gel dosimeter to quantify image noise and uniformity before radiation is delivered. Results: Slice-by-slice background subtraction effectively removes the variability in N{sub CT} observed across images acquired simultaneously using the multislice scanner and is the recommended background subtraction method when using a multislice CT system. Image noise was higher for the multislice system compared to the single slice scanner, but overall image quality was comparable between the two systems. Further study showed N{sub CT} was consistent across image slices acquired simultaneously using the multislice detector array for each detector configuration of the slice thicknesses examined. In addition, the multislice system was found to eliminate variations in N{sub CT} due to increasing x-ray tube load and reduce scanning time by a factor of 4 when compared to

  2. Characteristic Images Emerging From Recent Spie Medical Imaging Symposia

    NASA Astrophysics Data System (ADS)

    Wagner, Robert F.

    1987-01-01

    The purpose of this short tutorial is to highlight selected papers from recent SPIE conferences with emphasis on the areas of signal detection theory, statistical decision theory and pattern recognition, image evaluation, and image processing. The selection is biased toward the author's special areas of interest and, as is usual in reviews of this kind, a common set of threads are sought. The papers are referenced in terms of the SPIE volume number and paper number (000-00). The first common thread is that the volume numbers tend to be palindromes, namely, 454, 535, 626, and the present 767, and indicate the non-linear growth of the Society between annual Medical Imaging symposia.

  3. Investigation of the effect of tube voltage and imaging geometry on phase contrast imaging for a micro-CT system

    NASA Astrophysics Data System (ADS)

    Gui, Jianbao; Zou, Jing; Rong, Junyan; Hu, Zhanli; Zhang, Qiyang; Zheng, Hairong; Xia, Dan

    2012-03-01

    Based upon a bench-top micro-CT system, propagation-based phase-contrast imaging has been investigated using insects and a thin plastic sheet. The system mainly includes a micro-focus source with focal spot size of 13-20 μm and a cooled X-ray CCD detector with pixel size of 24 μm. The edge-enhancement effect can be found clearly in the acquired images. With a 0.5 mm thickness plastic edge phantom, the effects of X-ray tube voltage and imaging geometry on the phase-contrast imaging were investigated, and quantitative index, edge-enhancement index (EEI), were also calculated. In our study, an interesting phenomenon was observed that the phase-contrast effect becomes more pronounced as the tube voltage increases from 20 kVp to 90 kVp. Further investigation indicates that smaller focal spot size resulting from the reduction of tube current at higher tube voltage, has caused the unexpected phenomenon. Inferred from our results, phase-contrast effect is insensitive to the tube voltage in the range of 20-90 kVp (widely used in medical diagnosis); however, it is sensitive to the focal spot size. In addition, for the investigation of the effect of imaging geometry, an optimal geometric magnification range of 2.5-4.5 is suggested to get a good phase-contrast imaging for a micro-CT system with source-to-detector distance of 720 mm.

  4. Partial ring artifact on cardiac CT: image presentation and clinical implication.

    PubMed

    Tsai, Hsin-Yu; Chen, Min-Chi; Tsai, I-Chen; Chen, Clayton Chi-Chang

    2011-06-01

    In computed tomography (CT), the term "artifact" is applied to any systematic discrepancy between the CT numbers in the reconstructed image and the true attenuation coefficients of the object. A partial ring artifact in cardiac CT has a unique pattern and has not been previously reported in real clinical practice. In this report, we will demonstrate the images and animations of a cardiac CT which is affected by a partial ring artifact due to a broken detector module. The different characteristics of ring artifacts on routine and cardiac CT, and the implications for clinical interpretation will also be described. In summary, when a partial ring artifact is noted incidentally on cardiac CT, we suggest interpreting the images by reviewing reconstructed images from different RR-intervals to avoid unnecessary repeated scans and additional radiation exposure. PMID:21503707

  5. Gated cardiac imaging using a continuously rotating CT scanner: clinical evaluation of 91 patients

    SciTech Connect

    Oyama, Y.; Uji, T.; Hirayama, T.; Inada, Y.; Ishikawa, T.; Fujii, M.

    1984-05-01

    To produce electrocardiographically (ECG)-gated computed tomographic (CT) image of the heart, a post-data-acquisition ECG correlation technique was used in which data for missing angular projections are derived from the original scan data to complete 360 angular projections. Improved image quality and clinical usefulness were demonstrated compared with routine nongated CT and two-dimensional echocardiography. The equipment required for CT gating is of low cost, but the examination time is lengthy and less conveniently performed than echocardiography. However, when echocardiography is indecisive or suspected to be falsely negative, gated CT imaging of the heart is recommended.

  6. Improving abdomen tumor low-dose CT images using a fast dictionary learning based processing

    NASA Astrophysics Data System (ADS)

    Chen, Yang; Yin, Xindao; Shi, Luyao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis; Toumoulin, Christine

    2013-08-01

    In abdomen computed tomography (CT), repeated radiation exposures are often inevitable for cancer patients who receive surgery or radiotherapy guided by CT images. Low-dose scans should thus be considered in order to avoid the harm of accumulative x-ray radiation. This work is aimed at improving abdomen tumor CT images from low-dose scans by using a fast dictionary learning (DL) based processing. Stemming from sparse representation theory, the proposed patch-based DL approach allows effective suppression of both mottled noise and streak artifacts. The experiments carried out on clinical data show that the proposed method brings encouraging improvements in abdomen low-dose CT images with tumors.

  7. A correction method for nonlinear artifacts in CT imaging.

    PubMed

    Sun, Haining; Qiu, Shaokun; Lou, Shanshan; Liu, Jinjun; Li, Changjun; Jiang, Genmiao

    2004-01-01

    This work presents a new method to reduce nonlinear artifacts in computed tomography (CT). Based on the traditional water-equivalent beam hardening correction method, a new systematic iterative algorithm has been designed to modify the original spectrum, which is under the influences of certain added filter materials and some unknown factors. By incorporating the characters of polychromatic beam hardening and the insensibility and nonuniformity of detectors into consideration, a new polynomial function curve is calculated. The curve can calibrate CT raw data and reduce the nonlinear artifacts, such as shading artifacts, dark artifacts, cupping artifacts and ring artifacts, in soft tissue. Comparing with the traditional water-equivalent correction, results show that this method can significantly improve the image quality. Meanwhile, the method is pre-processing and will not increase the normal reconstruction time. That is, all the time-consuming works can be done before scanning patients. However, it is still depending on the size of phantoms currently used, and more detailed works need to be done in the future. PMID:17271926

  8. Multiresolution Analysis Using Wavelet, Ridgelet, and Curvelet Transforms for Medical Image Segmentation

    PubMed Central

    AlZubi, Shadi; Islam, Naveed; Abbod, Maysam

    2011-01-01

    The experimental study presented in this paper is aimed at the development of an automatic image segmentation system for classifying region of interest (ROI) in medical images which are obtained from different medical scanners such as PET, CT, or MRI. Multiresolution analysis (MRA) using wavelet, ridgelet, and curvelet transforms has been used in the proposed segmentation system. It is particularly a challenging task to classify cancers in human organs in scanners output using shape or gray-level information; organs shape changes throw different slices in medical stack and the gray-level intensity overlap in soft tissues. Curvelet transform is a new extension of wavelet and ridgelet transforms which aims to deal with interesting phenomena occurring along curves. Curvelet transforms has been tested on medical data sets, and results are compared with those obtained from the other transforms. Tests indicate that using curvelet significantly improves the classification of abnormal tissues in the scans and reduce the surrounding noise. PMID:21960988

  9. Multiresolution analysis using wavelet, ridgelet, and curvelet transforms for medical image segmentation.

    PubMed

    Alzubi, Shadi; Islam, Naveed; Abbod, Maysam

    2011-01-01

    The experimental study presented in this paper is aimed at the development of an automatic image segmentation system for classifying region of interest (ROI) in medical images which are obtained from different medical scanners such as PET, CT, or MRI. Multiresolution analysis (MRA) using wavelet, ridgelet, and curvelet transforms has been used in the proposed segmentation system. It is particularly a challenging task to classify cancers in human organs in scanners output using shape or gray-level information; organs shape changes throw different slices in medical stack and the gray-level intensity overlap in soft tissues. Curvelet transform is a new extension of wavelet and ridgelet transforms which aims to deal with interesting phenomena occurring along curves. Curvelet transforms has been tested on medical data sets, and results are compared with those obtained from the other transforms. Tests indicate that using curvelet significantly improves the classification of abnormal tissues in the scans and reduce the surrounding noise. PMID:21960988

  10. A new database for medical images and information

    NASA Astrophysics Data System (ADS)

    Tahmoush, Dave; Samet, Hanan

    2007-03-01

    We present a medical image and medical record database for the storage, research, transmission, and evaluation of medical images, as well as tele-medicine applications. Any medical image from a source that supports the DICOM standard can be stored and accessed, as well as associated analysis and annotations. Information and image retrieval can be done based on patient info, date, doctor's annotations, features in the images, or a spatial combination of features. Secure access and transmission is addressed for tele-medicine applications. This database application follows all HIPPA regulations.

  11. Medical applications of digital image morphing.

    PubMed

    Penska, Keith; Folio, Les; Bunger, Rolf

    2007-09-01

    The authors present a unique medical technical application for illustrating the success and/or failure of the physiological healing process as a dynamically morphed video. Two examples used in this report include the healing of a severely fractured humerus from an explosion in Iraq and the other of dramatic tissue destruction from a poisonous spider bite. For the humerus, several sequential x-rays obtained throughout orthopedic surgical procedures and the healing process were morphed together representing a time-lapsed video of the healing process. The end result is a video that demonstrates the healing process in an animation that radiologists envision and report to other clinicians. For the brown recluse spider bite, a seemingly benign skin lesion transforms into a wide gaping necrotic wound with dramatic appearance within days. This novel technique is not presented for readily apparent clinical advantage, rather, it may have more immediate application in providing treatment options to referring providers and/or patients, as well as educational value of healing or disease progression over time. Image morphing is one of those innovations that is just starting to come into its own. Morphing is an image processing technology that transforms one image into another by generating a series of intermediate synthetic images. It is the same process that Hollywood uses to turn people into animals in movies, for example. The ability to perform morphing, once restricted to high-end graphics workstations, is now widely available for desktop computers. The authors describe how a series of radiographic images were morphed into a short movie clip using readily available software and an average laptop. The resultant video showed the healing process of an open comminuted humerus fracture that helped demonstrate how amazingly the human body heals in a case presentation in a time-lapse fashion. PMID:17273920

  12. Image registration of MR and CT images using a frameless fiducial marker system.

    PubMed

    Kremser, C; Plangger, C; Bösecke, R; Pallua, A; Aichner, F; Felber, S R

    1997-01-01

    A new system of fiducial stereotactic markers that can easily be adapted to various imaging modalities without losing image registration was developed and tested. Utilizing MR and CT imaging the accuracy of the new system was evaluated with phantom studies and preliminary patient studies. The markers are clearly visible without artifacts on both imaging modalities. The clear delineation of the marker dots on the images enables an accurate automated marker detection. Using the marker system, image registration was found to yield an accuracy of up to 1 mm, depending on the imaging modality and the employed marker arrangement. The presented marker system shall improve patient comfort in comparison to conventional fixed stereotactic frames if repeated, highly accurate registrations are necessary over longer periods. PMID:9254002

  13. Soft tissue visualization using a highly efficient megavoltage cone beam CT imaging system

    NASA Astrophysics Data System (ADS)

    Ghelmansarai, Farhad A.; Bani-Hashemi, Ali; Pouliot, Jean; Calderon, Ed; Hernandez, Paco; Mitschke, Matthias; Aubin, Michelle; Bucci, Kara

    2005-04-01

    Recent developments in two-dimensional x-ray detector technology have made volumetric Cone Beam CT (CBCT) a feasible approach for integration with conventional medical linear accelerators. The requirements of a robust image guidance system for radiation therapy include the challenging combination of soft tissue sensitivity with clinically reasonable doses. The low contrast objects may not be perceptible with MV energies due to the relatively poor signal to noise ratio (SNR) performance. We have developed an imaging system that is optimized for MV and can acquire Megavoltage CBCT images containing soft tissue contrast using a 6MV x-ray beam. This system is capable of resolving relative electron density as low as 1% with clinically acceptable radiation doses. There are many factors such as image noise, x-ray scatter, improper calibration and acquisitions that have a profound effect on the imaging performance of CBCT and in this