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Medical Imaging, IEEE Transactions on

Issue 7 • Date July 2005

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Displaying Results 1 - 19 of 19
  • Table of contents

    Publication Year: 2005 , Page(s): c1
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  • IEEE Transactions on Medical Imaging publication information

    Publication Year: 2005 , Page(s): c2
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  • Guest Editorial Toward Molecular Imaging

    Publication Year: 2005 , Page(s): 829 - 831
    Cited by:  Papers (4)
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  • Functional imaging in small animals using X-ray computed Tomography -study of physiologic measurement reproducibility

    Publication Year: 2005 , Page(s): 832 - 843
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1384 KB) |  | HTML iconHTML  

    X-ray computed tomography (CT) has been traditionally used for morphologic analysis and in the recent past has been used for physiology imaging. This paper seeks to demonstrate functional CT as an effective tool for monitoring changes in tissue physiology associated with disease processes and cellular and molecular level therapeutic processes. We investigated the effect of noise and sampling time on the uncertainty of tissue physiologic parameters. A whole body compartmental model of mouse was formulated to simulate tissue time density curves and study the deviation of tissue physiologic parameters from their true values. These results were then used to determine the appropriate scanning protocols for the experimental studies. Dynamic contrast enhanced CT (DCE-CT) was performed in mice following the injection of hydrophilic iodinated contrast agent (CA) at three different injection rates, namely 0.5 ml/min, 1 ml/min, and 2.0 ml/min. These experiments probed the Nyquist sampling limit for reproducibility of tissue physiologic parameters. Separate experiments were performed with three mice at four different X-ray tube currents corresponding to different image noise values. A two-compartment model (2CM) model was formulated to describe the contrast kinematics in the kidney cortex. Three different 2CMs were implemented namely the 4-parameter (4P), 5-parameter (5P), and the 6-parameter (6P) model. The tissue kinematics is fitted to the models by using the Levenberg-Marquardt algorithm implemented in IDL (RSI Inc.) programming language to minimize the weighted sum of squares. The relevant tissue physiologic parameters extracted from the models are the renal blood flow (RBF), glomerular filtration rate (GFR), fractional plasma volume, fractional tubular volumes and urine formation rates. The experimental results indicate that the deviation of the tissue physiologic parameters is within the limits required for tracking disease physiology in vivo and thus small animal functi- - onal X-ray CT would be able to determine changes in tissue physiology in vivo. View full abstract»

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  • Imaging performance of a-PET: a small animal PET camera

    Publication Year: 2005 , Page(s): 844 - 852
    Cited by:  Papers (35)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (813 KB) |  | HTML iconHTML  

    The evolution of positron emission tomography (PET) imaging for small animals has led to the development of dedicated PET scanner designs with high resolution and sensitivity. The animal PET scanner achieves these goals for imaging small animals such as mice and rats. The scanner uses a pixelated Anger-logic detector for discriminating 2 × 2 × 10 mm3 crystals with 19-mm-diameter photomultiplier tubes. With a 19.7-cm ring diameter, the scanner has an axial length of 11.9 cm and operates exclusively in three-dimensional imaging mode, leading to very high sensitivity. Measurements show that the scanner design achieves a spatial resolution of 1.9 mm at the center of the field-of-view. Initially designed with gadolinium orthosilicate but changed to lutetium-yttrium orthosilicate, the scanner now achieves a sensitivity of 3.6% for a point source at the center of the field-of-view with an energy window of 250-665 keV. Iterative image reconstruction, together with accurate data corrections for scatter, random, and attenuation, are incorporated to achieve high-quality images and quantitative data. These results are demonstrated through our contrast recovery measurements as well as sample animal studies. View full abstract»

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  • Molecular imaging of small animals with a triple-head SPECT system using pinhole collimation

    Publication Year: 2005 , Page(s): 853 - 862
    Cited by:  Papers (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3189 KB) |  | HTML iconHTML  

    Pinhole collimation yields high sensitivity when the distance from the object to the aperture is small, as in the case of imaging small animals. Fine-resolution images may be obtained when the magnification is large since this mitigates the effect of detector resolution. Large magnifications in pinhole single-photon emission computed tomography (SPECT) may be obtained by using a collimator whose focal length is many times the radius of rotation. This may be achieved without truncation if the gamma camera is large. We describe a commercially available clinical scanner mated with pinhole collimation and an external linear stage. The pinhole collimation gives high magnification. The linear stage allows for helical pinhole SPECT. We have used the system to image radiolabeled molecules in phantoms and small animals. View full abstract»

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  • First results from the high-resolution mouseSPECT annular scintillation camera

    Publication Year: 2005 , Page(s): 863 - 867
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (942 KB) |  | HTML iconHTML  

    High-resolution single-photon emission computed tomography (SPECT) imaging in small animals tends to use long imaging times and large injected doses due to the poor sensitivity of single pinhole gamma cameras. To increase sensitivity while maintaining spatial resolution, we designed and constructed a multi-pinhole collimator array to replace the parallel hole collimators of a Ceraspect human SPECT brain scanner. The Ceraspect scanner is composed of an annular NaI(Tl) crystal within which the eight pinhole collimators (1-mm-diameter holes) rotate while projecting nonoverlapping images of the object onto the stationary annular crystal. In this manner, only one-eighth of a collimator rotation is required to acquire a full circle orbit tomographic data set. The imaging field of view (FOV) has a diameter of 25.6 mm in the transverse direction, which is sufficient to encompass a mouse in the transverse direction. The axial FOV is 25.6 mm at the center of the FOV and 13.9 mm at the edge of the transverse FOV. Data are currently acquired in step-and-shoot mode; however, the system is capable of list mode acquisition with the collimator continuously rotating. Images are reconstructed using a cone-beam ordered subsets expectation maximization method. The reconstructed spatial resolution of the system is 1.7 mm and the sensitivity at the center of the FOV is 13.8 cps/microCi. A whole-body bone scan of a mouse injected with [Tc-99 m]MDP clearly revealed skeletal structures such as the ribs and vertebral bodies. These preliminary results suggest that this approach is a good tradeoff between resolution and sensitivity and, with further refinement, may permit dynamic imaging in living animals. View full abstract»

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  • Evaluation of fully 3-D emission mammotomography with a compact cadmium zinc telluride detector

    Publication Year: 2005 , Page(s): 868 - 877
    Cited by:  Papers (21)  |  Patents (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1890 KB) |  | HTML iconHTML  

    A compact, dedicated cadmium zinc telluride (CZT) gamma camera coupled with a fully three-dimensional (3-D) acquisition system may serve as a secondary diagnostic tool for volumetric molecular imaging of breast cancers, particularly in cases when mammographic findings are inconclusive. The developed emission mammotomography system comprises a medium field-of-view, quantized CZT detector and 3-D positioning gantry. The intrinsic energy resolution, sensitivity and spatial resolution of the detector are evaluated with Tc-99m (140 keV) filled flood sources, capillary line sources, and a 3-D frequency-resolution phantom. To mimic realistic human pendant, uncompressed breast imaging, two different phantom shapes of an average sized breast, and three different lesion diameters are imaged to evaluate the system for 3-D mammotomography. Acquisition orbits not possible with conventional emission, or transmission, systems are designed to optimize the viewable breast volume while improving sampling of the breast and anterior chest wall. Complications in camera positioning about the patient necessitate a compromise in these two orbit design criteria. Image quality is evaluated with signal-to-noise ratios and contrasts of the lesions, both with and without additional torso phantom background. Reconstructed results indicate that 3-D mammotomography, incorporating a compact CZT detector, is a promising, dedicated breast imaging technique for visualization of tumors <1 cm in diameter. Additionally, there are no outstanding trajectories that consistently yield optimized quantitative lesion imaging parameters. Qualitatively, imaging breasts with realistic torso backgrounds (out-of-field activity) substantially alters image characteristics and breast morphology unless orbits which improve sampling are utilized. In practice, the sampling requirement may be less strict than initially anticipated. View full abstract»

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  • Fluorescent protein tomography scanner for small animal imaging

    Publication Year: 2005 , Page(s): 878 - 885
    Cited by:  Papers (33)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (804 KB) |  | HTML iconHTML  

    Microscopy of fluorescent proteins has enabled unprecedented insights into visualizing gene expression in living systems. Imaging deeper into animals, however, has been limited due to the lack of accurate imaging methods for the visible. We present a novel system designed to perform tomographic imaging of fluorescent proteins through whole animals. The tomographic method employed a multiangle, multiprojection illumination scheme, while detection was achieved using a highly sensitive charge-coupled device camera with appropriate filters. Light propagation was modeled using a modified solution to the diffusion equation to account for the high absorption and high scattering of tissue at the visible wavelengths. We show that the technique can quantitatively detect fluorescence with sub millimeter spatial resolution both in phantoms and in tissues. We conclude that the method could be applied in tomographic imaging of fluorescent proteins for in vivo targeting of different diseases and abnormalities. View full abstract»

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  • A three-dimensional registration method for automated fusion of micro PET-CT-SPECT whole-body images

    Publication Year: 2005 , Page(s): 886 - 893
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (350 KB) |  | HTML iconHTML  

    Micro positron emission tomography (PET) and micro single-photon emission computed tomography (SPECT), used for imaging small animals, have become essential tools in developing new pharmaceuticals and can be used, among other things, to test new therapeutic approaches in animal models of human disease, as well as to image gene expression. These imaging techniques can be used noninvasively in both detection and quantification. However, functional images provide little information on the structure of tissues and organs, which makes the localization of lesions difficult. Image fusion techniques can be exploited to map the functional images to structural images, such as X-ray computed tomography (CT), to support target identification and to facilitate the interpretation of PET or SPECT studies. Furthermore, the mapping of two functional images of SPECT and PET on a structural CT image can be beneficial for those in vivo studies that require two biological processes to be monitored simultaneously. This paper proposes an automated method for registering PET, CT, and SPECT images for small animals. A calibration phantom and a holder were used to determine the relationship among three-dimensional fields of view of various modalities. The holder was arranged in fixed positions on the couches of the scanners, and the spatial transformation matrix between the modalities was held unchanged. As long as objects were scanned together with the holder, the predetermined matrix could register the acquired tomograms from different modalities, independently of the imaged objects. In this work, the PET scan was performed by Concorde's microPET R4 scanner, and the SPECT and CT data were obtained using the Gamma Medica's X-SPECT/CT system. Fusion studies on phantoms and animals have been successfully performed using this method. For microPET-CT fusion, the maximum registration errors were 0.21 mm ± 0.14 mm, 0.26 mm ± 0.14 mm, and 0.45 mm ± 0.34 mm in the X (right-left), Y (upper lower), and Z (rostral-caudal) directions, respectively; for the microPET-SPECT fusion, they were 0.24 mm ± 0.14 mm, 0.28 mm ± 0.15 mm, and 0.54 mm ± 0.35 mm in the X, Y, and Z directions, respectively. The results indicate that thi- s simple method can be used in routine fusion studies. View full abstract»

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  • Image analysis for assessing molecular activity changes in time-dependent geometries

    Publication Year: 2005 , Page(s): 894 - 900
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1152 KB) |  | HTML iconHTML  

    In vivo fluorescence molecular imaging and tomography has facilitated monitoring of genomics and proteomics over time and on the same animal. A highly important issue, however, has been the robust registration of animals imaged at different time points to obtain accurate description of activity and location. This paper presents a method for aligning temporal data of small animals based on surface anatomical features and improving the accuracy of monitoring fluorophore distribution. The method can account for differences in the positioning and compression of small animals and can be extended to three-dimensional as well as to other imaging modalities. View full abstract»

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  • Mixture model analysis of DNA microarray images

    Publication Year: 2005 , Page(s): 901 - 909
    Cited by:  Papers (31)  |  Patents (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1319 KB) |  | HTML iconHTML  

    In this paper, we propose a new methodology for analysis of microarray images. First, a new gridding algorithm is proposed for determining the individual spots and their borders. Then, a Gaussian mixture model (GMM) approach is presented for the analysis of the individual spot images. The main advantages of the proposed methodology are modeling flexibility and adaptability to the data, which are well-known strengths of GMM. The maximum likelihood and maximum a posteriori approaches are used to estimate the GMM parameters via the expectation maximization algorithm. The proposed approach has the ability to detect and compensate for artifacts that might occur in microarray images. This is accomplished by a model-based criterion that selects the number of the mixture components. We present numerical experiments with artificial and real data where we compare the proposed approach with previous ones and existing software tools for microarray image analysis and demonstrate its advantages. View full abstract»

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  • Intravital leukocyte detection using the gradient inverse coefficient of variation

    Publication Year: 2005 , Page(s): 910 - 924
    Cited by:  Papers (22)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1327 KB) |  | HTML iconHTML  

    The problem of identifying and counting rolling leukocytes within intravital microscopy is of both theoretical and practical interest. Currently, methods exist for tracking rolling leukocytes in vivo, but these methods rely on manual detection of the cells. In this paper we propose a technique for accurately detecting rolling leukocytes based on Bayesian classification. The classification depends on a feature score, the gradient inverse coefficient of variation (GICOV), which serves to discriminate rolling leukocytes from a cluttered environment. The leukocyte detection process consists of three sequential steps: the first step utilizes an ellipse matching algorithm to coarsely identify the leukocytes by finding the ellipses with a locally maximal GICOV. In the second step, starting from each of the ellipses found in the first step, a B-spline snake is evolved to refine the leukocytes boundaries by maximizing the associated GICOV score. The third and final step retains only the extracted contours that have a GICOV score above the analytically determined threshold. Experimental results using 327 rolling leukocytes were compared to those of human experts and currently used methods. The proposed GICOV method achieves 78.6% leukocyte detection accuracy with 13.1% false alarm rate. View full abstract»

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  • Special issue on image management in enterprise environments for healthcare

    Publication Year: 2005 , Page(s): 925
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  • Special issue on functional source imaging

    Publication Year: 2005 , Page(s): 926
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  • 2006 IEEE International Symposium on Biomedical Imaging: From Nano to Macro (ISBI'06)

    Publication Year: 2005 , Page(s): 927
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  • IEEE Transactions on Biomedical Engineering search for editor-in-chief

    Publication Year: 2005 , Page(s): 928
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  • IEEE Transactions on Medical Imaging Information for authors

    Publication Year: 2005 , Page(s): c3
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  • Blank page [back cover]

    Publication Year: 2005 , Page(s): c4
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Aims & Scope

IEEE Transactions on Medical Imaging (T-MI) encourages the submission of manuscripts on imaging of body structures, morphology and function, and imaging of microscopic biological entities. The journal publishes original contributions on medical imaging achieved by various modalities, such as ultrasound, X-rays (including CT) magnetic resonance, radionuclides, microwaves, and light, as well as medical image processing and analysis, visualization, pattern recognition, and related methods. Studies involving highly technical perspectives are most welcome. The journal focuses on a unified common ground where instrumentation, systems, components, hardware and software, mathematics and physics contribute to the studies.

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Meet Our Editors

Editor-in-Chief
Michael Insana
Beckman Institute for Advanced Science and Technology
Department of Bioengineering
University of Illinois at Urbana-Champaign
Urbana, IL 61801 USA
m.f.i@ieee.org