WorldWideScience

Sample records for ct images acquired

  1. Evaluation of the reconstruction of image acquired from CT simulator to reduce metal artifact

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Ji Hun; Park, Jin Hong; Choi, Byung Don; Won, Hui Su; Chang, Nam Jun; Goo, Jang Hyun; Hong, Joo Wan [Dept. of Radiation Oncology, Seoul national university bundang hospital, Sungnam (Korea, Republic of)

    2014-12-15

    This study presents the usefulness assessment of metal artifact reduction for orthopedic implants(O-MAR) to decrease metal artifacts from materials with high density when acquired CT images. By CT simulator, original CT images were acquired from Gammex and Rando phantom and those phantoms inserted with high density materials were scanned for other CT images with metal artifacts and then O-MAR was applied to those images, respectively. To evaluate CT images using Gammex phantom, 5 regions of interest(ROIs) were placed at 5 organs and 3 ROIs were set up at points affected by artifacts. The averages of standard deviation(SD) and CT numbers were compared with a plan using original image. For assessment of variations in dose of tissue around materials with high density, the volume of a cylindrical shape was designed at 3 places in images acquired from Rando phantom by Eclipse. With 6 MV, 7-fields, 15x15cm{sup 2} and 100 cGy per fraction, treatment planning was created and the mean dose were compared with a plan using original image. In the test with the Gammex phantom, CT numbers had a few difference at established points and especially 3 points affected by artifacts had most of the same figures. In the case of O-MAR image, the more reduction in SD appeared at all of 8 points than non O-MAR image. In the test using the Rando Phantom, the variations in dose of tissue around high density materials had a few difference between original CT image and CT image with O-MAR. The CT images using O-MAR were acquired clearly at the boundary of tissue around high density materials and applying O-MAR was useful for correcting CT numbers.

  2. Hounsfield unit recovery in clinical cone beam CT images of the thorax acquired for image guided radiation therapy

    DEFF Research Database (Denmark)

    Thing, Rune Slot; Bernchou, Uffe; Mainegra-Hing, Ernesto

    2016-01-01

    A comprehensive artefact correction method for clinical cone beam CT (CBCT) images acquired for image guided radiation therapy (IGRT) on a commercial system is presented. The method is demonstrated to reduce artefacts and recover CT-like Hounsfield units (HU) in reconstructed CBCT images of five ...

  3. Hounsfield unit recovery in clinical cone beam CT images of the thorax acquired for image guided radiation therapy

    Science.gov (United States)

    Slot Thing, Rune; Bernchou, Uffe; Mainegra-Hing, Ernesto; Hansen, Olfred; Brink, Carsten

    2016-08-01

    A comprehensive artefact correction method for clinical cone beam CT (CBCT) images acquired for image guided radiation therapy (IGRT) on a commercial system is presented. The method is demonstrated to reduce artefacts and recover CT-like Hounsfield units (HU) in reconstructed CBCT images of five lung cancer patients. Projection image based artefact corrections of image lag, detector scatter, body scatter and beam hardening are described and applied to CBCT images of five lung cancer patients. Image quality is evaluated through visual appearance of the reconstructed images, HU-correspondence with the planning CT images, and total volume HU error. Artefacts are reduced and CT-like HUs are recovered in the artefact corrected CBCT images. Visual inspection confirms that artefacts are indeed suppressed by the proposed method, and the HU root mean square difference between reconstructed CBCTs and the reference CT images are reduced by 31% when using the artefact corrections compared to the standard clinical CBCT reconstruction. A versatile artefact correction method for clinical CBCT images acquired for IGRT has been developed. HU values are recovered in the corrected CBCT images. The proposed method relies on post processing of clinical projection images, and does not require patient specific optimisation. It is thus a powerful tool for image quality improvement of large numbers of CBCT images.

  4. Accurate IMRT fluence verification for prostate cancer patients using 'in-vivo' measured EPID images and in-room acquired kilovoltage cone-beam CT scans

    NARCIS (Netherlands)

    A.S.A.M. Ali (Ali Sid Ahmed M.); M.L.P. Dirkx (Maarten); R.M. Cools (Ruud); B.J.M. Heijmen (Ben)

    2013-01-01

    textabstractBackground: To investigate for prostate cancer patients the comparison of 'in-vivo' measured portal dose images (PDIs) with predictions based on a kilovoltage cone-beam CT scan (CBCT), acquired during the same treatment fraction, as an alternative for pre-treatment verification. For eval

  5. Acquired tracheomalacia: detection by expiratory CT scan.

    Science.gov (United States)

    Aquino, S L; Shepard, J A; Ginns, L C; Moore, R H; Halpern, E; Grillo, H C; McLoud, T C

    2001-01-01

    The purpose of this work was to determine whether cross-sectional area and coronal and sagittal diameter measurements of the trachea between inspiration and end-expiration on CT are significantly different between patients with acquired tracheomalacia and those without this condition. Inspiratory and end-expiratory CT scans of the trachea of 23 normal patients and 10 patients with acquired tracheomalacia were analyzed. Percent changes in cross-sectional area, coronal, and sagittal diameters were calculated. For patients with tracheomalacia, mean percent changes in the upper and middle trachea between inspiration and expiration were 49 and 44%; mean changes in the coronal and sagittal diameters in the upper and middle tracheal were 4 and 10% and 39 and 54%, respectively. Control group mean percent changes in the upper and middle tracheal area were 12 and 14%, respectively, and mean changes in the coronal and sagittal diameters in the upper and middle trachea were 4 and 4% and 11 and 13%, respectively. Significant differences were calculated for changes in cross-sectional area and sagittal diameter between groups (p 18% change in the upper trachea and 28% change in the midtrachea between inspiration and expiration were observed; the probability of tracheomalacia was 89-100%. The probability of tracheomalacia was > 89%, especially if the change in sagittal diameter was > 28%. By measuring changes in tracheal cross-sectional area and sagittal diameters between inspiratory and end-expiratory CT, a significant difference can be identified between normal patients and those with acquired tracheomalacia.

  6. CT images of gossypiboma

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Hae Jeong; Lim, Jong Nam; Choi, Young Chil; Park, Jeong Hee [College of Medicine, Kon-Kuk University, Seoul (Korea, Republic of)

    1994-04-15

    Surgical sponges retained after laparotomy can cause serious problem if they were not be identified in early state. In these circumstances abdominal CT yields the accurate diagnostic images. The purpose of this report is to present highly indicative findings permitting correct preoperative diagnosis of the gossypiboma. We experienced three cases in which CT showed the images sufficiently characteristic to suggest the correct preoperative diagnosis. We evaluated retrospectively the radiological images of gossypiboma confirmed by operation. Three patients were admitted due to palpable masses. Two female patients had medical histories of cesarean sections and a male patient had been operated due to malignant fibrous histiocytoma, previously. Abdominal CT scan of one case revealed huge ovoid hypodense mass with enhanced peripheral rim. Calcific spots and whirl-like stripes were noted within the lesion. Towel was found in pathologic specimen. CT images of two patients showed well-encapsulated, mixed fluid and soft tissue density mass with several gas bubbles. Surgical sponges were found within abscesses. The authors conclude that these characteristic CT findings and careful histories of surgery are very useful for correct pre-operative diagnosis and permit the guideline for the optimal plan of the surgical treatment.

  7. CT image of thymoma

    Energy Technology Data Exchange (ETDEWEB)

    Morioka, Nobuo; Shudo, Yuji; Jahana, Masanobu; Matsuki, Tsutomu; Kotani, Kazuhiko (Tottori Univ., Yonago (Japan). School of Medicine)

    1983-10-01

    Computor tomographic images of 11 patients who had had thymectomy for myasthenia gravis or thymoma were studied retrospectively. Of those 11 patients, malignant thymoma and benign condition including normal thymus were 6 and 5 respectively. On CT, calcification and lobulation with irregular margin seem to be reliable findings of malignancy. Defect or abscence of fatty plane and non-homogenous density are ancillary.

  8. Dynamic CT myocardial perfusion imaging.

    Science.gov (United States)

    Caruso, Damiano; Eid, Marwen; Schoepf, U Joseph; Jin, Kwang Nam; Varga-Szemes, Akos; Tesche, Christian; Mangold, Stefanie; Spandorfer, Adam; Laghi, Andrea; De Cecco, Carlo N

    2016-10-01

    Non-invasive cardiac imaging has rapidly evolved during the last decade due to advancements in CT based technologies. Coronary CT angiography has been shown to reliably assess coronary anatomy and detect high risk coronary artery disease. However, this technique is limited to anatomical assessment, thus non-invasive techniques for functional assessment of the heart are necessary. CT myocardial perfusion is a new CT based technique that provides functional assessment of the myocardium and allows for a comprehensive assessment of coronary artery disease with a single modality when combined with CTA. This review aims to discuss dynamic CT myocardial perfusion as a new technique in the assessment of CAD.

  9. A minimum spanning forest based classification method for dedicated breast CT images

    NARCIS (Netherlands)

    Pike, R.; Sechopoulos, I.; Fei, B.

    2015-01-01

    PURPOSE: To develop and test an automated algorithm to classify different types of tissue in dedicated breast CT images. METHODS: Images of a single breast of five different patients were acquired with a dedicated breast CT clinical prototype. The breast CT images were processed by a multiscale bila

  10. Robust Optic Nerve Segmentation on Clinically Acquired CT.

    Science.gov (United States)

    Panda, Swetasudha; Asman, Andrew J; Delisi, Michael P; Mawn, Louise A; Galloway, Robert L; Landman, Bennett A

    2014-03-21

    The optic nerve is a sensitive central nervous system structure, which plays a critical role in many devastating pathological conditions. Several methods have been proposed in recent years to segment the optic nerve automatically, but progress toward full automation has been limited. Multi-atlas methods have been successful for brain segmentation, but their application to smaller anatomies remains relatively unexplored. Herein we evaluate a framework for robust and fully automated segmentation of the optic nerves, eye globes and muscles. We employ a robust registration procedure for accurate registrations, variable voxel resolution and image field-of-view. We demonstrate the efficacy of an optimal combination of SyN registration and a recently proposed label fusion algorithm (Non-local Spatial STAPLE) that accounts for small-scale errors in registration correspondence. On a dataset containing 30 highly varying computed tomography (CT) images of the human brain, the optimal registration and label fusion pipeline resulted in a median Dice similarity coefficient of 0.77, symmetric mean surface distance error of 0.55 mm, symmetric Hausdorff distance error of 3.33 mm for the optic nerves. Simultaneously, we demonstrate the robustness of the optimal algorithm by segmenting the optic nerve structure in 316 CT scans obtained from 182 subjects from a thyroid eye disease (TED) patient population.

  11. Automatic nonrigid registration of whole body CT mice images.

    Science.gov (United States)

    Li, Xia; Yankeelov, Thomas E; Peterson, Todd E; Gore, John C; Dawant, Benoit M

    2008-04-01

    Three-dimensional intra- and intersubject registration of image volumes is important for tasks that include quantification of temporal/longitudinal changes, atlas-based segmentation, computing population averages, or voxel and tensor-based morphometry. While a number of methods have been proposed to address this problem, few have focused on the problem of registering whole body image volumes acquired either from humans or small animals. These image volumes typically contain a large number of articulated structures, which makes registration more difficult than the registration of head images, to which the majority of registration algorithms have been applied. This article presents a new method for the automatic registration of whole body computed tomography (CT) volumes, which consists of two main steps. Skeletons are first brought into approximate correspondence with a robust point-based method. Transformations so obtained are refined with an intensity-based nonrigid registration algorithm that includes spatial adaptation of the transformation's stiffness. The approach has been applied to whole body CT images of mice, to CT images of the human upper torso, and to human head and neck CT images. To validate the authors method on soft tissue structures, which are difficult to see in CT images, the authors use coregistered magnetic resonance images. They demonstrate that the approach they propose can successfully register image volumes even when these volumes are very different in size and shape or if they have been acquired with the subjects in different positions.

  12. Functional CT imaging of prostate cancer

    Science.gov (United States)

    Henderson, Elizabeth; Milosevic, Michael F.; Haider, Masoom A.; Yeung, Ivan W. T.

    2003-09-01

    The purpose of this paper is to investigate the distribution of blood flow (F), mean capillary transit time (Tc), capillary permeability (PS) and blood volume (vb) in prostate cancer using contrast-enhanced CT. Nine stage T2-T3 prostate cancer patients were enrolled in the study. Following bolus injection of a contrast agent, a time series of CT images of the prostate was acquired. Functional maps showing the distribution of F, Tc, PS and vb within the prostate were generated using a distributed parameter tracer kinetic model, the adiabatic approximation to the tissue homogeneity model. The precision of the maps was assessed using covariance matrix analysis. Finally, maps were compared to the findings of standard clinical investigations. Eight of the functional maps demonstrated regions of increased F, PS and vb, the locations of which were consistent with the results of standard clinical investigations. However, model parameters other than F could only be measured precisely within regions of high F. In conclusion functional CT images of cancer-containing prostate glands demonstrate regions of elevated F, PS and vb. However, caution should be used when applying a complex tracer kinetic model to the study of prostate cancer since not all parameters can be measured precisely in all areas.

  13. Software for Acquiring Image Data for PIV

    Science.gov (United States)

    Wernet, Mark P.; Cheung, H. M.; Kressler, Brian

    2003-01-01

    PIV Acquisition (PIVACQ) is a computer program for acquisition of data for particle-image velocimetry (PIV). In the PIV system for which PIVACQ was developed, small particles entrained in a flow are illuminated with a sheet of light from a pulsed laser. The illuminated region is monitored by a charge-coupled-device camera that operates in conjunction with a data-acquisition system that includes a frame grabber and a counter-timer board, both installed in a single computer. The camera operates in "frame-straddle" mode where a pair of images can be obtained closely spaced in time (on the order of microseconds). The frame grabber acquires image data from the camera and stores the data in the computer memory. The counter/timer board triggers the camera and synchronizes the pulsing of the laser with acquisition of data from the camera. PIVPROC coordinates all of these functions and provides a graphical user interface, through which the user can control the PIV data-acquisition system. PIVACQ enables the user to acquire a sequence of single-exposure images, display the images, process the images, and then save the images to the computer hard drive. PIVACQ works in conjunction with the PIVPROC program which processes the images of particles into the velocity field in the illuminated plane.

  14. CT Imaging: Basics and New Trends

    Science.gov (United States)

    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.

  15. Automatic dental arch detection and panoramic image synthesis from CT images.

    Science.gov (United States)

    Sa-Ing, Vera; Wangkaoom, Kongyot; Thongvigitmanee, Saowapak S

    2013-01-01

    Due to accurate 3D information, computed tomography (CT), especially cone-beam CT or dental CT, has been widely used for diagnosis and treatment planning in dentistry. Axial images acquired from both medical and dental CT scanners can generate synthetic panoramic images similar to typical 2D panoramic radiographs. However, the conventional way to reconstruct the simulated panoramic images is to manually draw the dental arch on axial images. In this paper, we propose a new fast algorithm for automatic detection of the dental arch. Once the dental arch is computed, a series of synthetic panoramic images as well as a ray-sum panoramic image can be automatically generated. We have tested the proposed algorithm on 120 CT axial images and all of them can provide the decent estimate of the dental arch. The results show that our proposed algorithm can mostly detect the correct dental arch.

  16. CT features of pulmonary mycobacterial disease in patients with acquired immunodeficiency syndrome

    Institute of Scientific and Technical Information of China (English)

    朱莹

    2013-01-01

    Objective To study the CT features of pulmonary non-tuberculous mycobacteria (NTM) disease in patients with acquired immunodeficiency syndrome (AIDS) and explore the different CT appearances between AIDS-NTM and AIDS-TB. Methods CT findings of pulmonary NTM

  17. Intestinal disease in acquired immunodeficiency: evaluation by CT

    Energy Technology Data Exchange (ETDEWEB)

    Knollmann, F.D.; Maeurer, J.; Felix, R. [Strahlenklinik und Poliklinik, Virchow-Klinikum, Medizinische Fakultaet der Humboldt-Universitaet, Augustenburger Platz 1, D-13 353 Berlin (Germany); Gruenewald, T.; Pohle, H.D. [Medizinische Klinik II mit Schwerpunkt Infektionskrankheiten, Virchow-Klinikum, Medizinische Fakultaet der Humboldt-Universitaet, Augustenburger Platz 1, D-13 353 Berlin (Germany); Adler, A.; Hintze, R.E. [Klinik fuer Innere Medizin mit dem Schwerpunkt Gastroenterologie, Zentrale Interdisziplinaere Endoskopie, Virchow-Klinikum, Medizinische Fakultaet der Humboldt-Universitaet, Augustenburger Platz 1, D-13 353 Berlin (Germany)

    1997-12-01

    Intestinal symptoms affect most AIDS patients at some point in their disease. The purpose of this study was to evaluate the use of CT in this setting. A total of 339 abdominal CT exams were reviewed for signs of intestinal disease. Abdominal CT scans of 45 patients with intestinal symptoms were compared with colonoscopy and histologic data. The CT results were correlated with CD4{sup +} T-lymphocyte counts and patient survival. More than 14 % of all abdominal CT exams displayed signs of enteric disease. Of the 45 patients studied with both CT and colonoscopy, 35 (78 %) had signs of intestinal disease by CT. Of these 35 patients, colonoscopic signs of an intestinal lesion were found in 29 and histologic proof of disease was established in 30 cases. Colonoscopy and histology detected 8 lesions missed by CT. There were 14 cases of unspecific colitis, 15 cases of cytomegalovirus (CMV) colitis, and 4 cases of enteric tuberculosis as per biopsy. Five patients presented with Kaposi`s sarcoma and 1 with a non-Hodgkin`s lymphoma. Neither colonoscopic nor CT signs of intestinal disease did reliably distinguish between histologic subgroups. Specifically, CMV colitis could not be distinguished from unspecific colitis. CD4{sup +} T-lymphocyte counts for histologic subgroups were not significantly different, either. No colonoscopic or histologic feature predicted survival, whereas low CD4 counts and ascites on CT indicated a poor prognosis. Whereas CT detects signs of intestinal disease in most AIDS patients, these signs remain largely unspecific. Colonoscopy and biopsies provide no consistently valid standard with which to compare CT because of controversial sensitivity and specificity of these methods. The CT technique detects small bowel as well as extraintestinal disease. Therefore, CT is an important diagnostic modality in abdominal disease of immunocompromised patients. (orig.) With 7 figs., 6 tabs., 30 refs.

  18. Myocardial perfusion imaging with dual energy CT.

    Science.gov (United States)

    Jin, Kwang Nam; De Cecco, Carlo N; Caruso, Damiano; Tesche, Christian; Spandorfer, Adam; Varga-Szemes, Akos; Schoepf, U Joseph

    2016-10-01

    Dual-energy CT (DECT) enables simultaneous use of two different tube voltages, thus different x-ray absorption characteristics are acquired in the same anatomic location with two different X-ray spectra. The various DECT techniques allow material decomposition and mapping of the iodine distribution within the myocardium. Static dual-energy myocardial perfusion imaging (sCTMPI) using pharmacological stress agents demonstrate myocardial ischemia by single snapshot images of myocardial iodine distribution. sCTMPI gives incremental values to coronary artery stenosis detected on coronary CT angiography (CCTA) by showing consequent reversible or fixed myocardial perfusion defects. The comprehensive acquisition of CCTA and sCTMPI offers extensive morphological and functional evaluation of coronary artery disease. Recent studies have revealed that dual-energy sCTMPI shows promising diagnostic accuracy for the detection of hemodynamically significant coronary artery disease compared to single-photon emission computed tomography, invasive coronary angiography, and cardiac MRI. The aim of this review is to present currently available DECT techniques for static myocardial perfusion imaging and recent clinical applications and ongoing investigations.

  19. Acquired portosystemic collaterals: anatomy and imaging*

    Science.gov (United States)

    Leite, Andréa Farias de Melo; Mota Jr., Américo; Chagas-Neto, Francisco Abaeté; Teixeira, Sara Reis; Elias Junior, Jorge; Muglia, Valdair Francisco

    2016-01-01

    Portosystemic shunts are enlarged vessels that form collateral pathological pathways between the splanchnic circulation and the systemic circulation. Although their causes are multifactorial, portosystemic shunts all have one mechanism in common-increased portal venous pressure, which diverts the blood flow from the gastrointestinal tract to the systemic circulation. Congenital and acquired collateral pathways have both been described in the literature. The aim of this pictorial essay was to discuss the distinct anatomic and imaging features of portosystemic shunts, as well as to provide a robust method of differentiating between acquired portosystemic shunts and similar pathologies, through the use of illustrations and schematic drawings. Imaging of portosystemic shunts provides subclinical markers of increased portal venous pressure. Therefore, radiologists play a crucial role in the identification of portosystemic shunts. Early detection of portosystemic shunts can allow ample time to perform endovascular shunt operations, which can relieve portal hypertension and prevent acute or chronic complications in at-risk patient populations. PMID:27777479

  20. Acquired portosystemic collaterals: anatomy and imaging

    Energy Technology Data Exchange (ETDEWEB)

    Leite, Andrea Farias de Melo; Mota Junior, Americo, E-mail: andreafariasm@gmail.com [Instituto de Medicina Integral Professor Fernando Figueira de Pernambuco (IMIP), Recife, PE (Brazil); Chagas-Neto, Francisco Abaete [Universidade de Fortaleza (UNIFOR), Fortaleza, CE (Brazil); Teixeira, Sara Reis; Elias Junior, Jorge; Muglia, Valdair Francisco [Universidade de Sao Paulo (FMRP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina

    2016-07-15

    Portosystemic shunts are enlarged vessels that form collateral pathological pathways between the splanchnic circulation and the systemic circulation. Although their causes are multifactorial, portosystemic shunts all have one mechanism in common - increased portal venous pressure, which diverts the blood flow from the gastrointestinal tract to the systemic circulation. Congenital and acquired collateral pathways have both been described in the literature. The aim of this pictorial essay was to discuss the distinct anatomic and imaging features of portosystemic shunts, as well as to provide a robust method of differentiating between acquired portosystemic shunts and similar pathologies, through the use of illustrations and schematic drawings. Imaging of portosystemic shunts provides subclinical markers of increased portal venous pressure. Therefore, radiologists play a crucial role in the identification of portosystemic shunts. Early detection of portosystemic shunts can allow ample time to perform endovascular shunt operations, which can relieve portal hypertension and prevent acute or chronic complications in at-risk patient populations. (author)

  1. 4D-CT motion estimation using deformable image registration and 5D respiratory motion modeling

    OpenAIRE

    2008-01-01

    Four-dimensional computed tomography (4D-CT) imaging technology has been developed for radiation therapy to provide tumor and organ images at the different breathing phases. In this work, a procedure is proposed for estimating and modeling the respiratory motion field from acquired 4D-CT imaging data and predicting tissue motion at the different breathing phases. The 4D-CT image data consist of series of multislice CT volume segments acquired in ciné mode. A modified optical flow deformable i...

  2. Efficient Abdominal Segmentation on Clinically Acquired CT with SIMPLE Context Learning.

    Science.gov (United States)

    Xu, Zhoubing; Burke, Ryan P; Lee, Christopher P; Baucom, Rebeccah B; Poulose, Benjamin K; Abramson, Richard G; Landman, Bennett A

    2015-03-20

    Abdominal segmentation on clinically acquired computed tomography (CT) has been a challenging problem given the inter-subject variance of human abdomens and complex 3-D relationships among organs. Multi-atlas segmentation (MAS) provides a potentially robust solution by leveraging label atlases via image registration and statistical fusion. We posit that the efficiency of atlas selection requires further exploration in the context of substantial registration errors. The selective and iterative method for performance level estimation (SIMPLE) method is a MAS technique integrating atlas selection and label fusion that has proven effective for prostate radiotherapy planning. Herein, we revisit atlas selection and fusion techniques for segmenting 12 abdominal structures using clinically acquired CT. Using a re-derived SIMPLE algorithm, we show that performance on multi-organ classification can be improved by accounting for exogenous information through Bayesian priors (so called context learning). These innovations are integrated with the joint label fusion (JLF) approach to reduce the impact of correlated errors among selected atlases for each organ, and a graph cut technique is used to regularize the combined segmentation. In a study of 100 subjects, the proposed method outperformed other comparable MAS approaches, including majority vote, SIMPLE, JLF, and the Wolz locally weighted vote technique. The proposed technique provides consistent improvement over state-of-the-art approaches (median improvement of 7.0% and 16.2% in DSC over JLF and Wolz, respectively) and moves toward efficient segmentation of large-scale clinically acquired CT data for biomarker screening, surgical navigation, and data mining.

  3. Efficient multi-atlas abdominal segmentation on clinically acquired CT with SIMPLE context learning.

    Science.gov (United States)

    Xu, Zhoubing; Burke, Ryan P; Lee, Christopher P; Baucom, Rebeccah B; Poulose, Benjamin K; Abramson, Richard G; Landman, Bennett A

    2015-08-01

    Abdominal segmentation on clinically acquired computed tomography (CT) has been a challenging problem given the inter-subject variance of human abdomens and complex 3-D relationships among organs. Multi-atlas segmentation (MAS) provides a potentially robust solution by leveraging label atlases via image registration and statistical fusion. We posit that the efficiency of atlas selection requires further exploration in the context of substantial registration errors. The selective and iterative method for performance level estimation (SIMPLE) method is a MAS technique integrating atlas selection and label fusion that has proven effective for prostate radiotherapy planning. Herein, we revisit atlas selection and fusion techniques for segmenting 12 abdominal structures using clinically acquired CT. Using a re-derived SIMPLE algorithm, we show that performance on multi-organ classification can be improved by accounting for exogenous information through Bayesian priors (so called context learning). These innovations are integrated with the joint label fusion (JLF) approach to reduce the impact of correlated errors among selected atlases for each organ, and a graph cut technique is used to regularize the combined segmentation. In a study of 100 subjects, the proposed method outperformed other comparable MAS approaches, including majority vote, SIMPLE, JLF, and the Wolz locally weighted vote technique. The proposed technique provides consistent improvement over state-of-the-art approaches (median improvement of 7.0% and 16.2% in DSC over JLF and Wolz, respectively) and moves toward efficient segmentation of large-scale clinically acquired CT data for biomarker screening, surgical navigation, and data mining.

  4. Efficient abdominal segmentation on clinically acquired CT with SIMPLE context learning

    Science.gov (United States)

    Xu, Zhoubing; Burke, Ryan P.; Lee, Christopher P.; Baucom, Rebeccah B.; Poulose, Benjamin K.; Abramson, Richard G.; Landman, Bennett A.

    2015-03-01

    Abdominal segmentation on clinically acquired computed tomography (CT) has been a challenging problem given the inter-subject variance of human abdomens and complex 3-D relationships among organs. Multi-atlas segmentation (MAS) provides a potentially robust solution by leveraging label atlases via image registration and statistical fusion. We posit that the efficiency of atlas selection requires further exploration in the context of substantial registration errors. The selective and iterative method for performance level estimation (SIMPLE) method is a MAS technique integrating atlas selection and label fusion that has proven effective for prostate radiotherapy planning. Herein, we revisit atlas selection and fusion techniques for segmenting 12 abdominal structures using clinically acquired CT. Using a re-derived SIMPLE algorithm, we show that performance on multi-organ classification can be improved by accounting for exogenous information through Bayesian priors (so called context learning). These innovations are integrated with the joint label fusion (JLF) approach to reduce the impact of correlated errors among selected atlases for each organ, and a graph cut technique is used to regularize the combined segmentation. In a study of 100 subjects, the proposed method outperformed other comparable MAS approaches, including majority vote, SIMPLE, JLF, and the Wolz locally weighted vote technique. The proposed technique provides consistent improvement over state-of-the-art approaches (median improvement of 7.0% and 16.2% in DSC over JLF and Wolz, respectively) and moves toward efficient segmentation of large-scale clinically acquired CT data for biomarker screening, surgical navigation, and data mining.

  5. Hepatic CT image query using Gabor features

    Institute of Scientific and Technical Information of China (English)

    Chenguang Zhao(赵晨光); Hongyan Cheng(程红岩); Tiange Zhuang(庄天戈)

    2004-01-01

    A retrieval scheme for liver computerize tomography (CT) images based on Gabor texture is presented.For each hepatic CT image, we manually delineate abnormal regions within liver area. Then, a continuous Gabor transform is utilized to analyze the texture of the pathology bearing region and extract the corresponding feature vectors. For a given sample image, we compare its feature vector with those of other images. Similar images with the highest rank are retrieved. In experiments, 45 liver CT images are collected, and the effectiveness of Gabor texture for content based retrieval is verified.

  6. Mass preserving image registration for lung CT

    DEFF Research Database (Denmark)

    Gorbunova, Vladlena; Sporring, Jon; Lo, Pechin;

    2012-01-01

    on four groups of data: 44 pairs of longitudinal inspiratory chest CT scans with small difference in lung volume; 44 pairs of longitudinal inspiratory chest CT scans with large difference in lung volume; 16 pairs of expiratory and inspiratory CT scans; and 5 pairs of images extracted at end exhale and end...... inhale phases of 4D-CT images. Registration errors, measured as the average distance between vessel tree centerlines in the matched images, are significantly lower for the proposed mass preserving image registration method in the second, third and fourth group, while there is no statistically significant......This paper presents a mass preserving image registration algorithm for lung CT images. To account for the local change in lung tissue intensity during the breathing cycle, a tissue appearance model based on the principle of preservation of total lung mass is proposed. This model is incorporated...

  7. Image reconstruction for brain CT slices

    Institute of Scientific and Technical Information of China (English)

    吴建明; 施鹏飞

    2004-01-01

    Different modalities in biomedical images, like CT, MRI and PET scanners, provide detailed cross-sectional views of human anatomy. This paper introduces three-dimensional brain reconstruction based on CT slices. It contains filtering, fuzzy segmentation, matching method of contours, cell array structure and image animation. Experimental results have shown its validity. The innovation is matching method of contours and fuzzy segmentation algorithm of CT slices.

  8. An evaluation on CT image acquisition method for medical VR applications

    Science.gov (United States)

    Jang, Seong-wook; Ko, Junho; Yoo, Yon-sik; Kim, Yoonsang

    2017-02-01

    Recent medical virtual reality (VR) applications to minimize re-operations are being studied for improvements in surgical efficiency and reduction of operation error. The CT image acquisition method considering three-dimensional (3D) modeling for medical VR applications is important, because the realistic model is required for the actual human organ. However, the research for medical VR applications has focused on 3D modeling techniques and utilized 3D models. In addition, research on a CT image acquisition method considering 3D modeling has never been reported. The conventional CT image acquisition method involves scanning a limited area of the lesion for the diagnosis of doctors once or twice. However, the medical VR application is required to acquire the CT image considering patients' various postures and a wider area than the lesion. A wider area than the lesion is required because of the necessary process of comparing bilateral sides for dyskinesia diagnosis of the shoulder, pelvis, and leg. Moreover, patients' various postures are required due to the different effects on the musculoskeletal system. Therefore, in this paper, we perform a comparative experiment on the acquired CT images considering image area (unilateral/bilateral) and patients' postures (neutral/abducted). CT images are acquired from 10 patients for the experiments, and the acquired CT images are evaluated based on the length per pixel and the morphological deviation. Finally, by comparing the experiment results, we evaluate the CT image acquisition method for medical VR applications.

  9. SPECT/CT workflow and imaging protocols

    Energy Technology Data Exchange (ETDEWEB)

    Beckers, Catherine [University Hospital of Liege, Division of Nuclear Medicine and Oncological Imaging, Department of Medical Physics, Liege (Belgium); Hustinx, Roland [University Hospital of Liege, Division of Nuclear Medicine and Oncological Imaging, Department of Medical Physics, Liege (Belgium); Domaine Universitaire du Sart Tilman, Service de Medecine Nucleaire et Imagerie Oncologique, CHU de Liege, Liege (Belgium)

    2014-05-15

    Introducing a hybrid imaging method such as single photon emission computed tomography (SPECT)/CT greatly alters the routine in the nuclear medicine department. It requires designing new workflow processes and the revision of original scheduling process and imaging protocols. In addition, the imaging protocol should be adapted for each individual patient, so that performing CT is fully justified and the CT procedure is fully tailored to address the clinical issue. Such refinements often occur before the procedure is started but may be required at some intermediate stage of the procedure. Furthermore, SPECT/CT leads in many instances to a new partnership with the radiology department. This article presents practical advice and highlights the key clinical elements which need to be considered to help understand the workflow process of SPECT/CT and optimise imaging protocols. The workflow process using SPECT/CT is complex in particular because of its bimodal character, the large spectrum of stakeholders, the multiplicity of their activities at various time points and the need for real-time decision-making. With help from analytical tools developed for quality assessment, the workflow process using SPECT/CT may be separated into related, but independent steps, each with its specific human and material resources to use as inputs or outputs. This helps identify factors that could contribute to failure in routine clinical practice. At each step of the process, practical aspects to optimise imaging procedure and protocols are developed. A decision-making algorithm for justifying each CT indication as well as the appropriateness of each CT protocol is the cornerstone of routine clinical practice using SPECT/CT. In conclusion, implementing hybrid SPECT/CT imaging requires new ways of working. It is highly rewarding from a clinical perspective, but it also proves to be a daily challenge in terms of management. (orig.)

  10. The stylohyoid chain: CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Uysal Ramadan, Selma, E-mail: uysalselma@yahoo.co [Department of Radiology, Ankara Training and Research Hospital, Ankara 06590 (Turkey); Goekharman, Dilek, E-mail: gokharman@ttnet.net.t [Department of Radiology, Ankara Training and Research Hospital, Ankara 06590 (Turkey); Kosar, Pinar, E-mail: pkosar@hotmail.co [Department of Radiology, Ankara Training and Research Hospital, Ankara 06590 (Turkey); Kacar, Mahmut, E-mail: mkacar1961@gamil.co [Department of Radiology, Ankara Training and Research Hospital, Ankara 06590 (Turkey); Kosar, Ugur, E-mail: ugurkosar@hotmail.co [Department of Radiology, Ankara Training and Research Hospital, Ankara 06590 (Turkey)

    2010-09-15

    We aimed in this report to discuss the embryology, anatomy, theories of ossification and symptoms, clinical presentation, and diagnosis of the stylohyoid chain (SHC) variations, together with the role of radiographs, computed tomography (CT) and three-dimensional (3D)-CT in showing these variations. Because CT/3D-CT additionally facilitates visualization of the entire SHC with different axes, it is the most valuable method for establishing the relationship between the SHC and the surrounding tissue. SHC variation can be discovered during CT performed for indications other than ossified SHC. It is important to diagnose whether or not the SHC is ossified, since one of the treatment procedures in ossified SHC is total excision. If the clinician and radiologist are aware of these variations observed in the SHC, patients with vague symptoms may be spared unnecessary investigations and may be properly diagnosed earlier.

  11. Quantitative Techniques in PET-CT Imaging

    NARCIS (Netherlands)

    Basu, Sandip; Zaidi, Habib; Holm, Soren; Alavi, Abass

    2011-01-01

    The appearance of hybrid PET/CT scanners has made quantitative whole body scanning of radioactive tracers feasible. This paper deals with the novel concepts for assessing global organ function and disease activity based on combined functional (PET) and structural (CT or MR) imaging techniques, their

  12. Intracranial Hemorrhage Annotation for CT Brain Images

    Directory of Open Access Journals (Sweden)

    Tong Hau Lee

    2011-01-01

    Full Text Available In this paper, we created a decision-making model to detect intracranial hemorrhage and adopted Expectation Maximization(EM segmentation to segment the Computed Tomography (CT images. In this work, basically intracranial hemorrhage is classified into two main types which are intra-axial hemorrhage and extra-axial hemorrhage. In order to ease classification, contrast enhancement is adopted to finetune the contrast of the hemorrhage. After that, k-means is applied to group the potential and suspicious hemorrhagic regions into one cluster. The decision-making process is to identify whether the suspicious regions are hemorrhagic regions or non-regions of interest. After the hemorrhagic detection, the images are segmented into brain matter and cerebrospinal fluid (CSF by using expectation-maximization (EM segmentation. The acquired experimental results are evaluated in terms of recall and precision. The encouraging results have been attained whereby the proposed system has yielded 0.9333 and 0.8880 precision for extra-axial and intra-axial hemorrhagic detection respectively, whereas recall rate obtained is 0.9245 and 0.8043 for extra-axial and intra-axial hemorrhagic detection respectively.

  13. Virtual CT laparoscopic imaging using intravenous cholangiography with helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Masafumi; Ishibashi, Masatoshi; Nishimura, Hiroshi; Hayabuchi, Naofumi [Kurume Univ., Fukuoka (Japan). School of Medicine

    2000-08-01

    Laparoscopic cholecystectomy is a reatively new technology that allows for minimally invasive treatment of cholelithiasis. The purpose of this paper is to demonstrate the feasibility of virtual laparoscopic imaging using helical CT cholangiography with volume rendering technique. We used the technique with ten patients with suspected gallbladder abnormalities. Our imaging sets produced high quality 3D images with excellent visualization in 70% (7/10) of all cases. Virtual laparoscopic imaging was also compared with other imaging techniques and imaging using helical scans can proved useful in preoperative imaging. Furthermore, virtual laparoscopic imaging using helical scans can in surgical planning and serve as a visual aid in discussions between radiologists, surgeons, and patients. (author)

  14. Radionuclide brain imaging in acquired immunodeficiency syndrome (AIDS)

    Energy Technology Data Exchange (ETDEWEB)

    Costa, D.C.; Gacinovic, S.; Miller, R.F. [London University College Medical School, Middlesex Hospital, London (United Kingdom)

    1995-09-01

    Infection with the Human Immunodeficiency Virus type 1 (HIV-1) may produce a variety of central nervous system (CNS) symptoms and signs. CNS involvement in patients with the Acquired Immunodeficiency Syndrome (AIDS) includes AIDS dementia complex or HIV-1 associated cognitive/motor complex (widely known as HIV encephalopathy), progressive multifocal leucoencephalopathy (PML), opportunistic infections such as Toxoplasma gondii, TB, Cryptococcus and infiltration by non-Hodgkin`s B cell lymphoma. High resolution structural imaging investigations, either X-ray Computed Tomography (CT scan) or Magnetic Resonance Imaging (MRI) have contributed to the understanding and definition of cerebral damage caused by HIV encephalopathy. Atrophy and mainly high signal scattered white matter abnormalities are commonly seen with MRI. PML produces focal white matter high signal abnormalities due to multiple foci of demyelination. However, using structural imaging techniques there are no reliable parameters to distinguish focal lesions due to opportunistic infection (Toxoplasma gondii abscess) from neoplasm (lymphoma infiltration). It is studied the use of radionuclide brain imaging techniques in the investigation of HIV infected patients. Brain perfusion Single Photon Emission Tomography (SPET), neuroreceptor and Positron Emission Tomography (PET) studies are reviewed. Greater emphasis is put on the potential of some radiopharmaceuticals, considered to be brain tumour markers, to distinguish intracerebral lymphoma infiltration from Toxoplasma infection. SPET with {sup 201}Tl using quantification (tumour to non-tumour radioactivity ratios) appears a very promising technique to identify intracerebral lymphoma.

  15. SPECT/CT imaging in bone scintigraphy of a case of clavicular osteoma

    Directory of Open Access Journals (Sweden)

    Yuka Yamamoto

    2014-05-01

    diphosphonate (HMDP. Whole-body image showed a focus of intensely increased uptake in the clavicle. Single photon emission computed tomography/ computed tomography (SPECT/CT images were also acquired and clearly showed intense uptake at the tumor site. Integrated SPECT/CT imaging supplies both functional and anatomic information about bone: the SPECT imaging improves sensitivity compared with planar imaging, the CT imaging provides precise localization of the abnormal uptake, and information on the shape and structure of the abnormalities improves the specificity of the diagnosis.

  16. Blind Analysis of CT Image Noise Using Residual Denoised Images

    CERN Document Server

    Roychowdhury, Sohini; Alessio, Adam

    2016-01-01

    CT protocol design and quality control would benefit from automated tools to estimate the quality of generated CT images. These tools could be used to identify erroneous CT acquisitions or refine protocols to achieve certain signal to noise characteristics. This paper investigates blind estimation methods to determine global signal strength and noise levels in chest CT images. Methods: We propose novel performance metrics corresponding to the accuracy of noise and signal estimation. We implement and evaluate the noise estimation performance of six spatial- and frequency- based methods, derived from conventional image filtering algorithms. Algorithms were tested on patient data sets from whole-body repeat CT acquisitions performed with a higher and lower dose technique over the same scan region. Results: The proposed performance metrics can evaluate the relative tradeoff of filter parameters and noise estimation performance. The proposed automated methods tend to underestimate CT image noise at low-flux levels...

  17. Multi-institutional MicroCT image comparison of image-guided small animal irradiators

    Science.gov (United States)

    Johnstone, Chris D.; Lindsay, Patricia; E Graves, Edward; Wong, Eugene; Perez, Jessica R.; Poirier, Yannick; Ben-Bouchta, Youssef; Kanesalingam, Thilakshan; Chen, Haijian; E Rubinstein, Ashley; Sheng, Ke; Bazalova-Carter, Magdalena

    2017-07-01

    To recommend imaging protocols and establish tolerance levels for microCT image quality assurance (QA) performed on conformal image-guided small animal irradiators. A fully automated QA software SAPA (small animal phantom analyzer) for image analysis of the commercial Shelley micro-CT MCTP 610 phantom was developed, in which quantitative analyses of CT number linearity, signal-to-noise ratio (SNR), uniformity and noise, geometric accuracy, spatial resolution by means of modulation transfer function (MTF), and CT contrast were performed. Phantom microCT scans from eleven institutions acquired with four image-guided small animal irradiator units (including the commercial PXi X-RAD SmART and Xstrahl SARRP systems) with varying parameters used for routine small animal imaging were analyzed. Multi-institutional data sets were compared using SAPA, based on which tolerance levels for each QA test were established and imaging protocols for QA were recommended. By analyzing microCT data from 11 institutions, we established image QA tolerance levels for all image quality tests. CT number linearity set to R 2  >  0.990 was acceptable in microCT data acquired at all but three institutions. Acceptable SNR  >  36 and noise levels  1.5 lp mm-1 for MTF  =  0.2) was obtained at all but four institutions due to their large image voxel size used (>0.275 mm). Ten of the eleven institutions passed the set QA tolerance for geometric accuracy (2000 HU for 30 mgI ml-1). We recommend performing imaging QA with 70 kVp, 1.5 mA, 120 s imaging time, 0.20 mm voxel size, and a frame rate of 5 fps for the PXi X-RAD SmART. For the Xstrahl SARRP, we recommend using 60 kVp, 1.0 mA, 240 s imaging time, 0.20 mm voxel size, and 6 fps. These imaging protocols should result in high quality images that pass the set tolerance levels on all systems. Average SAPA computation time for complete QA analysis for a 0.20 mm voxel, 400 slice Shelley phantom microCT data set

  18. SPECT/CT and tumour imaging

    Energy Technology Data Exchange (ETDEWEB)

    Abikhzer, Gad [Rambam Health Care Campus, Department of Nuclear Medicine, Haifa (Israel); Keidar, Zohar [Rambam Health Care Campus, Department of Nuclear Medicine, Haifa (Israel); Technion - Israel Institute of Technology, The Ruth and Bruce Rappaport Faculty of Medicine, Haifa (Israel)

    2014-05-15

    Scintigraphic techniques are sensitive imaging modalities in the diagnosis and follow-up of cancer patients providing the functional and metabolic activity characteristics of the tumour. Hybrid SPECT/CT improves the diagnostic accuracy of these well-established imaging techniques by precise anatomical localization and characterization of morphological findings, differentiation between foci of physiological and pathological tracer uptake, resulting in a significant impact on patient management and more definitive interpretations. The use of SPECT/CT has been studied in a variety of applications in tumour imaging which are reviewed in this article. By combining functional and anatomical information in a single imaging session, SPECT/CT has become a one-stop cancer imaging modality. (orig.)

  19. Comparison of stroke infarction between CT perfusion and diffusion weighted imaging: preliminary results

    Science.gov (United States)

    Abd. Rahni, Ashrani Aizzuddin; Arka, Israna Hossain; Chellappan, Kalaivani; Mukari, Shahizon Azura; Law, Zhe Kang; Sahathevan, Ramesh

    2016-03-01

    In this paper we present preliminary results of comparison of automatic segmentations of the infarct core, between that obtained from CT perfusion (based on time to peak parameter) and diffusion weighted imaging (DWI). For each patient, the two imaging volumes were automatically co-registered to a common frame of reference based on an acquired CT angiography image. The accuracy of image registration is measured by the overlap of the segmented brain from both images (CT perfusion and DWI), measured within their common field of view. Due to the limitations of the study, DWI was acquired as a follow up scan up to a week after initial CT based imaging. However, we found significant overlap of the segmented brain (Jaccard indices of approximately 0.8) and the percentage of infarcted brain tissue from the two modalities were still fairly highly correlated (correlation coefficient of approximately 0.9). The results are promising with more data needed in future for clinical inference.

  20. Advances in CT imaging for urolithiasis

    Directory of Open Access Journals (Sweden)

    Yasir Andrabi

    2015-01-01

    Full Text Available 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.

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

    Directory of Open Access Journals (Sweden)

    Nishchint Jain

    2016-01-01

    Full Text Available 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.

  2. Mass preserving image registration for lung CT

    DEFF Research Database (Denmark)

    Gorbunova, Vladlena; Sporring, Jon; Lo, Pechin Chien Pau

    2012-01-01

    This paper presents a mass preserving image registration algorithm for lung CT images. To account for the local change in lung tissue intensity during the breathing cycle, a tissue appearance model based on the principle of preservation of total lung mass is proposed. This model is incorporated...... into a standard image registration framework with a composition of a global affine and several free-form B-Spline transformations with increasing grid resolution. The proposed mass preserving registration method is compared to registration using the sum of squared intensity differences as a similarity function...... inhale phases of 4D-CT images. Registration errors, measured as the average distance between vessel tree centerlines in the matched images, are significantly lower for the proposed mass preserving image registration method in the second, third and fourth group, while there is no statistically significant...

  3. Image Analysis in CT Angiography

    NARCIS (Netherlands)

    Manniesing, R.

    2006-01-01

    In this thesis we develop and validate novel image processing techniques for the analysis of vascular structures in medical images. First a new type of filter is proposed which is capable of enhancing vascular structures while suppressing noise in the remainder of the image. This filter is based on

  4. The maxillomandibular ameloblastoma: CT and MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Na, Dong Gyu; Han, Moon Hee; Kim, Myung Jin; Chang, Kee Hyun [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1994-02-15

    We retrospectively performed this study to evaluate the characteristic findings of maxillomandibular ameloblastomas on CT and MR imaging. We reviewed histologically proved 12 cases of ameloblastomas, of which 7 cases were postoperative recurrent tumors, one of twelve cases was presumed ameloblastic carcinoma. Eleven cases were examined with CT and 3 cases with MR. The types were solid in 4, unicystic in 4, and mixed in the rest 4. CT and MRI of 11 ameloblastomas showed concentric expansile mass (n = 11), cortical bone thinning and focal bone destruction by the tumors (n = 9), well-margined, expansile destruction of surrounding sturctures (n = 9), focal bulging of the tumors (n = 6) and focal poorly-marginated invasion of tissue planes (n = 4). Ameloblastic carcinoma showed ill-defined irregular margin, aggressive invasion of surrounding structures and hematogeneous lung metastasis. Unerupted teeth or mural modules were found in unicystic ameloblastomas. All three tumors examined by MRI showed isointensity to muscle on T1 weighted images and slight hyperintensity on T2 weighted images. The wall, septa and solid portions of the tumors were strongly enhanced on MR imaging. There was no difference in CT ro MR finding between primary and recurrent tumors. Ameloblastomas showed solid, cystic or mixed pattern, and commonly well marginated expansile contour with local aggressiveness. Presence of mural nodules on CT in unicystic ameloblastoma with unerupted tooth was helpful in distinguishing ameloblastoma from dentigerous cyst.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez-Romero, Ruth, E-mail: rrromero@salud.madrid.org; Castro-Tejero, Pablo, E-mail: pablo.castro@salud.madrid.org [Servicio de Radiofísica y Protección Radiológica, Hospital Universitario Puerta de Hierro Majadahonda, 28222 Madrid (Spain)

    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

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

    Science.gov (United States)

    Rodríguez-Romero, Ruth; Castro-Tejero, Pablo

    2014-04-01

    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). 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. 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 patterns of higher

  7. Modern CT and PET/CT imaging of the liver; Moderne CT- und PET/CT-Bildgebung der Leber

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, J.; Heusner, T.A.; Riegger, C.; Reichelt, D.; Kuhlemann, J.; Antoch, G.; Blondin, D. [Medizinische Fakultaet, Heinrich-Heine-Universitaet Duesseldorf, Institut fuer Diagnostische und Interventionelle Radiologie, Duesseldorf (Germany)

    2011-08-15

    Computed tomography (CT) is now widely available and represents an important and rapid method for the diagnostics of acute liver disease, characterization of focal liver lesions, planning of interventional therapy measures and postintervention control. In recent years CT has not become less important despite the increasing value of magnetic resonance imaging (MRI). By the use of different contrast medium phases good characterization of space-occupying lesions can be achieved. For the diagnostics of hepatocellular carcinoma (HCC) a triphasic examination protocol should always be implemented. The introduction of dual energy CT increased the sensitivity of imaging of hypervascularized and hypovascularized liver lesions and by the use of virtual native imaging it has become possible to avoid additional native imaging which reduces the x-ray exposition of patients. Positron emission tomography (PET) has an advantage for imaging in oncology because nearly the complete body of the patient can be screened and this is the main indication for PET/CT (whole-body staging). For purely hepatic problems 18F-fluorodeoxyglucose (FDG)-PET/CT using diagnostic CT data has a higher precision than CT alone but is inferior to MRI. (orig.) [German] Die Computertomographie (CT) ist heute breit verfuegbar und stellt eine wichtige und schnelle Methode zur Diagnostik akuter Lebererkrankungen, der Artdiagnostik fokaler Leberlaesionen und der Planung interventioneller Therapiemassnahmen sowie der postinterventionellen Kontrolle dar. In den letzten Jahren hat die CT trotz des zunehmenden Stellenwerts der Magnetresonanztomographie (MRT) nicht an Bedeutung verloren. Durch den Einsatz unterschiedlicher Kontrastmittelphasen kann meist eine gute Charakterisierung von Raumforderungen erfolgen. Bei der Diagnostik des hepatozellulaeren Karzinoms (HCC) sollte beispielsweise immer ein triphasisches Untersuchungsprotokoll angewendet werden. Mit Einfuehrung der Dual-energy-CT hat die Sensitivitaet in der

  8. Attenuation correction of myocardial SPECT images with X-ray CT. Effects of registration errors between X-ray CT and SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Yasuyuki; Murase, Kenya [Osaka Univ., Suita (Japan). Graduate School of Medicine; Higashino, Hiroshi [Ehime Prefectural Imabari Hospital (Japan); Mochizuki, Teruhito [Ehime Univ., Matsuyama (Japan). School of Medicine; Motomura, Nobutoku [Toshiba Corp., Otawara, Tochigi (Japan). Medical Engineering Lab.

    2002-09-01

    Attenuation correction with an X-ray CT image is a new method to correct attenuation on SPECT imaging, but the effect of the registration errors between CT and SPECT images is unclear. In this study, we investigated the effects of the registration errors on myocardial SPECT, analyzing data from a phantom and a human volunteer. Registerion (fusion) of the X-ray CT and SPECT images was done with standard packaged software in three dimensional fashion, by using linked transaxial, coronal and sagittal images. In the phantom study, and X-ray CT image was shifted 1 to 3 pixels on the x, y and z axes, and rotated 6 degrees clockwise. Attenuation correction maps generated from each misaligned X-ray CT image were used to reconstruct misaligned SPECT images of the phantom filled with {sup 201}Tl. In a human volunteer, X-ray CT was acquired in different conditions (during inspiration vs. expiration). CT values were transferred to an attenuation constant by using straight lines; an attenuation constant of 0/cm in the air (CT value=-1,000 HU) and that of 0.150/cm in water (CT value=0 HU). For comparison, attenuation correction with transmission CT (TCT) data and an external {gamma}-ray source ({sup 99m}Tc) was also applied to reconstruct SPECT images. Simulated breast attenuation with a breast attachment, and inferior wall attenuation were properly corrected by means of the attenuation correction map generated from X-ray CT. As pixel shift increased, deviation of the SPECT images increased in misaligned images in the phantom study. In the human study, SPECT images were affected by the scan conditions of the X-ray CT. Attenuation correction of myocardial SPECT with an X-ray CT image is a simple and potentially beneficial method for clinical use, but accurate registration of the X-ray CT to SPECT image is essential for satisfactory attenuation correction. (author)

  9. Kaposi sarcoma and lymphadenopathy syndrome: limitations of abdominal CT in acquired immunodeficiency syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Moon, K.L. Jr.; Federle, M.P.; Abrams, D.I.; Volberding, P.; Lewis, B.J.

    1984-02-01

    Abdominal computed tomography (CT) was performed in 31 patients with Kaposi sarcoma (KS) related to acquired immunodeficiency syndrome (AIDS), three patients with classic KS, and 12 patients with the newly described lymphadenopathy syndrome (LNS). The frequency, distribution, and appearance of lymphadenopathy and splenomegaly were similar in the AIDS-related KS and LNS groups. Rectal and perirectal disease was identified in 86% of homosexual men studied; rectal KS could not be distinguished from proctitis on CT criteria alone. No CT abnormalities were seen in patients with classic KS. The CT demonstration of retroperitoneal, mesenteric, or pelvic adenopathy or of rectal or perirectal disease in patients with AIDS-related KS is not necessarily indicative of widespread involvement with the disease.

  10. Techniques in Iterative Proton CT Image Reconstruction

    CERN Document Server

    Penfold, Scott

    2015-01-01

    This is a review paper on some of the physics, modeling, and iterative algorithms in proton computed tomography (pCT) image reconstruction. The primary challenge in pCT image reconstruction lies in the degraded spatial resolution resulting from multiple Coulomb scattering within the imaged object. Analytical models such as the most likely path (MLP) have been proposed to predict the scattered trajectory from measurements of individual proton location and direction before and after the object. Iterative algorithms provide a flexible tool with which to incorporate these models into image reconstruction. The modeling leads to a large and sparse linear system of equations that can efficiently be solved by projection methods-based iterative algorithms. Such algorithms perform projections of the iterates onto the hyperlanes that are represented by the linear equations of the system. They perform these projections in possibly various algorithmic structures, such as block-iterative projections (BIP), string-averaging...

  11. Stress myocardial perfusion imaging with multidetector CT

    NARCIS (Netherlands)

    A. Rossi (Alexia); D. Merkus (Daphne); E. Klotz (Ernst); N.R.A. Mollet (Nico); P.J. de Feyter (Pim); G.P. Krestin (Gabriel)

    2014-01-01

    textabstractComputed tomographic (CT) coronary angiography is a well-established, noninvasive imaging modality for detection of coronary stenosis, but it has limited accuracy in demonstrating whether a coronary stenosis is hemodynamically significant. An additional functional test is often required

  12. Stress myocardial perfusion imaging with multidetector CT

    NARCIS (Netherlands)

    A. Rossi (Alexia); D. Merkus (Daphne); E. Klotz (Ernst); N.R.A. Mollet (Nico); P.J. de Feyter (Pim); G.P. Krestin (Gabriel)

    2014-01-01

    textabstractComputed tomographic (CT) coronary angiography is a well-established, noninvasive imaging modality for detection of coronary stenosis, but it has limited accuracy in demonstrating whether a coronary stenosis is hemodynamically significant. An additional functional test is often required

  13. CT imaging of enhanced oil recovery experiments

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. CT imaging of enhanced oil recovery experiments

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. A CT-, PET- and MR-imaging-compatible hyperbaric pressure chamber for baromedical research

    DEFF Research Database (Denmark)

    Hansen, Kasper; Søvsø Szocska Hansen, Esben; Tolbod, Lars P;

    2015-01-01

    OBJECTIVES: We describe the development of a novel preclinical rodent-sized pressure chamber system compatible with computed tomography (CT), positron emission tomography (PET) and magnetic resonance imaging (MRI) that allows continuous uncompromised and minimally invasive data acquisition...... different tissues in the MRI phantoms. CONCLUSION: This study demonstrates a pressure chamber system compatible with CT, PET and MRI. We found that no correction in image intensity was required with pressurisation up to 1.013 mPa for any imaging modality. CT, PET or MRI can be used to obtain anatomical...... throughout hyperbaric exposures. The effect of various pressures on the acquired image intensity obtained with different CT, PET and MRI phantoms are characterised. MATERIAL AND METHODS: Tissue-representative phantom models were examined with CT, PET or MRI at normobaric pressure and hyperbaric pressures up...

  16. Denoising CT Images using wavelet transform

    Directory of Open Access Journals (Sweden)

    Lubna Gabralla

    2015-05-01

    Full Text Available Image denoising is one of the most significant tasks especially in medical image processing, where the original images are of poor quality due the noises and artifacts introduces by the acquisition systems. In this paper, we propose a new image denoising scheme by modifying the wavelet coefficients using soft-thresholding method, we present a comparative study of different wavelet denoising techniques for CT images and we discuss the obtained results. The denoising process rejects noise by thresholding in the wavelet domain. The performance is evaluated using Peak Signal-to-Noise Ratio (PSNR and Mean Squared Error (MSE. Finally, Gaussian filter provides better PSNR and lower MSE values. Hence, we conclude that this filter is an efficient one for preprocessing medical images.

  17. Tin-filter enhanced dual-energy-CT: image quality and accuracy of CT numbers in virtual noncontrast imaging.

    Science.gov (United States)

    Kaufmann, Sascha; Sauter, Alexander; Spira, Daniel; Gatidis, Sergios; Ketelsen, Dominik; Heuschmid, Martin; Claussen, Claus D; Thomas, Christoph

    2013-05-01

    To measure and compare the objective image quality of true noncontrast (TNC) images with virtual noncontrast (VNC) images acquired by tin-filter-enhanced, dual-source, dual-energy computed tomography (DECT) of upper abdomen. Sixty-three patients received unenhanced abdominal CT and enhanced abdominal DECT (100/140 kV with tin filter) in portal-venous phase. VNC images were calculated from the DECT datasets using commercially available software. The mean attenuation of relevant tissues and image quality were compared between the TNC and VNC images. Image quality was rated objectively by measuring image noise and the sharpness of object edges using custom-designed software. Measurements were compared using Student two-tailed t-test. Correlation coefficients for tissue attenuation measurements between TNC and VNC were calculated and the relative deviations were illustrated using Bland-Altman plots. Mean attenuation differences between TNC and VNC (HUTNC - HUVNC) image sets were as follows: right liver lobe -4.94 Hounsfield units (HU), left liver lobe -3.29 HU, vena cava -2.19 HU, spleen -7.46 HU, pancreas 1.29 HU, fat -11.14 HU, aorta 1.29 HU, bone marrow 36.83 HU (all P Mean image noise was significantly higher in TNC images (P images (P = .19). The Hounsfield units in VNC images closely resemble TNC images in the majority of the organs of the upper abdomen (kidneys, liver, pancreas). In spleen and fat, Hounsfield numbers in VNC images are tend to be higher than in TNC images. VNC images show a low image noise and satisfactory edge sharpness. Other criteria of image quality and the depiction of certain lesions need to be evaluated additionally. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

  18. SU-E-J-241: Creation of Ventilation CT From Daily 4D CTs Or 4D Conebeam CTs Acquired During IGRT for Thoracic Cancers

    Energy Technology Data Exchange (ETDEWEB)

    Tai, A; Ahunbay, E; Li, X [Medical College of Wisconsin, Milwaukee, WI (United States)

    2014-06-01

    Purpose: To develop a method to create ventilation CTs from daily 4D CTs or 4D KV conebeam CTs (4DCBCT) acquired during image-guided radiation therapy (IGRT) for thoracic tumors, and to explore the potential for using the ventilation CTs as a means for early detection of lung injury during radiation treatment. Methods: 4DCT acquired using an in-room CT (CTVision, Siemens) and 4DCBCT acquired using the X-ray Volume Imaging (XVI) system (Infinity, Elekta) for representative lung cancer patients were analyzed. These 4D data sets were sorted into 10 phase images. A newly-available deformable image registration tool (ADMIRE, Elekta) is used to deform the phase images at the end of exhale (EE) to the phase images at the end of inhale (EI). The lung volumes at EI and EE were carefully contoured using an intensity-based auto-contour tool and then manually edited. The ventilation images were calculated from the variations of CT numbers of those voxels masked by the lung contour at EI between the registered phase images. The deformable image registration is also performed between the daily 4D images and planning 4DCT, and the resulting deformable field vector (DFV) is used to deform the planning doses to the daily images by an in-house Matlab program. Results: The ventilation images were successfully created. The tide volumes calculated using the ventilation images agree with those measured through volume difference of contours at EE and EI, indicating the accuracy of ventilation images. The association between the delivered doses and the change of lung ventilation from the daily ventilation CTs is identified. Conclusions: A method to create the ventilation CT using daily 4DCTs or 4D KV conebeam CTs was developed and demonstrated.

  19. A single CdZnTe detector for simultaneous CT/SPECT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Barber, W.C. E-mail: bill@barber.uscf.edu; Iwata, Koji; Hasegawa, B.H.; Bennett, P.R.; Cirignano, L.J.; Shah, K.S

    2003-06-01

    Clinical CT/SPECT systems acquire CT and SPECT data sequentially using different detectors in close proximity to minimise patient movement and interscan delay. We have developed a prototype simultaneous CT/SPECT imager, using a single CdZnTe detector, with the goal of improving image coregistration and decreasing scan time. A 16-pixel CdZnTe detector was operated in pulse-counting mode with 50 ns shaping time. Energy discrimination is used to separate the CT and SPECT data. Simultaneous SPECT and CT images were obtained for a phantom with the X-ray flux limited to reduce pulse pile-up in the radionuclide energy window. At 140 keV, the efficiency and energy resolution are 70% and 10%, respectively, and were constant for fluence rates up to 10{sup 3} cps per detector element for 140 keV gamma rays, but degrade rapidly at higher fluence rates. In pulse-counting mode, the maximum count rate of 10{sup 3} cps per element from the CdZnTe detector is sufficient for SPECT imaging, but is considerably lower than the fluence rates encountered in CT. The smallest lesion visually detectable in SPECT is 9 mm and the CT spatial resolution is smaller than 4.5 mm. Image registration is intrinsic because the data can be acquired simultaneously with a single detector with the same reconstruction geometry.

  20. Clinical micro-CT for dental imaging

    Science.gov (United States)

    Youn, Hanbean; Cho, Min Kook; Shon, Cheol-Soon; Cho, Bong Hae; Kim, Chang Hyuk; Kim, Ho Kyung

    2009-02-01

    We exploit the development of a clinical computed microtomography (micro-CT) system for dental imaging. While the conventional dental CT simply serves implant treatment, the clinical dental micro-CT may provide clinicians with a histologic evaluation. To investigate the feasibility of the realization of a dental micro-CT, we have constructed an experimental test system which mainly consists of a microfocus x-ray source, a rotational subject holder, and a flat-panel detector. The flat-panel detector is based on a matrix-addressed photodiode array coupled to a CsI:Tl scintillator. The detective quantum efficiency (DQE) of the detector was measured as a function of magnification based on the measured modulation-transfer function (MTF) and noise-power spectrum (NPS). The best MTF and DQE performances were achieved at the magnification factor of 3. Similar tendency of the spatial resolving power in tomography was also observed with a wire phantom having a 25 μm diameter. From the investigation of tomographs reconstructed from a humanoid skull phantom, the application of magnification in the system largely reduced both signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for a fixed dose at the entrance surface of the detector, 1.2 mGy, while this setup increased the dose at the object plane from 4.7 mGy to 19.1 mGy for the magnification factor from 2 to 4, respectively. Although the quantum mottles at the high magnification factor tackled the practical use in the clinic, the information contained in the magnified CT images was quite promising.

  1. Segmentation and separation of venous vasculatures in liver CT images

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  4. Head and neck imaging with PET and PET/CT: artefacts from dental metallic implants

    Energy Technology Data Exchange (ETDEWEB)

    Goerres, Gerhard W.; Hany, Thomas F.; Kamel, Ehab; von Schulthess, Gustav K.; Buck, Alfred [Division of Nuclear Medicine, Department of Radiology, University Hospital Zurich (Switzerland)

    2002-03-01

    Germanium-68 based attenuation correction (PET{sub Ge68}) is performed in positron emission tomography (PET) imaging for quantitative measurements. With the recent introduction of combined in-line PET/CT scanners, CT data can be used for attenuation correction. Since dental implants can cause artefacts in CT images, CT-based attenuation correction (PET{sub CT}) may induce artefacts in PET images. The purpose of this study was to evaluate the influence of dental metallic artwork on the quality of PET images by comparing non-corrected images and images attenuation corrected by PET{sub Ge68} and PET{sub CT}. Imaging was performed on a novel in-line PET/CT system using a 40-mAs scan for PET{sub CT} in 41 consecutive patients with high suspicion of malignant or inflammatory disease. In 17 patients, additional PET{sub Ge68} images were acquired in the same imaging session. Visual analysis of fluorine-18 fluorodeoxyglucose (FDG) distribution in several regions of the head and neck was scored on a 4-point scale in comparison with normal grey matter of the brain in the corresponding PET images. In addition, artefacts adjacent to dental metallic artwork were evaluated. A significant difference in image quality scoring was found only for the lips and the tip of the nose, which appeared darker on non-corrected than on corrected PET images. In 33 patients, artefacts were seen on CT, and in 28 of these patients, artefacts were also seen on PET imaging. In eight patients without implants, artefacts were seen neither on CT nor on PET images. Direct comparison of PET{sub Ge68} and PET{sub CT} images showed a different appearance of artefacts in 3 of 17 patients. Malignant lesions were equally well visible using both transmission correction methods. Dental implants, non-removable bridgework etc. can cause artefacts in attenuation-corrected images using either a conventional {sup 68}Ge transmission source or the CT scan obtained with a combined PET/CT camera. We recommend that the

  5. Incidental Detection of Interstitial Pregnancy on CT Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Byung Seok [Chungnam National University Hospital, Daejeon (Korea, Republic of); Park, Mi Hyun [Dankook University Hospital, Cheonan (Korea, Republic of)

    2010-02-15

    Ectopic pregnancy is a potentially life-threatening condition. Detection of ectopic pregnancy on CT images is rare. In this case, we describe the CT findings of interstitial pregnancy both before and after rupture. If CT images demonstrate the presence of a strong enhancing ring-like mass in the pelvis, ectopic pregnancy should be considered

  6. The Mobius AIRO mobile CT for image-guided proton therapy: Characterization & commissioning.

    Science.gov (United States)

    Oliver, Jasmine A; Zeidan, Omar A; Meeks, Sanford L; Shah, Amish P; Pukala, Jason; Kelly, Patrick; Ramakrishna, Naren R; Willoughby, Twyla R

    2017-05-01

    The purpose of this study was to characterize the Mobius AIRO Mobile CT System for localization and image-guided proton therapy. This is the first known application of the AIRO for proton therapy. Five CT images of a Catphan(®) 504 phantom were acquired on the AIRO Mobile CT System, Varian EDGE radiosurgery system cone beam CT (CBCT), Philips Brilliance Big Bore 16 slice CT simulator, and Siemens SOMATOM Definition AS 20 slice CT simulator. DoseLAB software v.6.6 was utilized for image quality analysis. Modulation transfer function, scaling discrepancy, geometric distortion, spatial resolution, overall uniformity, minimum uniformity, contrast, high CNR, and maximum HU deviation were acquired. Low CNR was acquired manually using the CTP515 module. Localization accuracy and CT Dose Index were measured and compared to reported values on each imaging device. For treatment delivery systems (Edge and Mevion), the localization accuracy of the 3D imaging systems were compared to 2D imaging systems on each system. The AIRO spatial resolution was 0.21 lp mm(-1) compared with 0.40 lp mm(-1) for the Philips CT Simulator, 0.37 lp mm(-1) for the Edge CBCT, and 0.35 lp mm(-1) for the Siemens CT Simulator. AIRO/Siemens and AIRO/Philips differences exceeded 100% for scaling discrepancy (191.2% and 145.8%). The AIRO exhibited higher dose (>27 mGy) than the Philips CT Simulator. Localization accuracy (based on the MIMI phantom) was 0.6° and 0.5 mm. Localization accuracy (based on Stereophan) demonstrated maximum AIRO-kV/kV shift differences of 0.1 mm in the x-direction, 0.1 mm in the y-direction, and 0.2 mm in the z-direction. The localization accuracy of AIRO was determined to be within 0.6° and 0.5 mm despite its slightly lower image quality overall compared to other CT imaging systems at our institution. Based on our study, the Mobile AIRO CT system can be utilized accurately and reliably for image-guided proton therapy. © 2017 The Authors. Journal of Applied Clinical Medical

  7. 3D Interpolation Method for CT Images of the Lung

    Directory of Open Access Journals (Sweden)

    Noriaki Asada

    2003-06-01

    Full Text Available A 3-D image can be reconstructed from numerous CT images of the lung. The procedure reconstructs a solid from multiple cross section images, which are collected during pulsation of the heart. Thus the motion of the heart is a special factor that must be taken into consideration during reconstruction. The lung exhibits a repeating transformation synchronized to the beating of the heart as an elastic body. There are discontinuities among neighboring CT images due to the beating of the heart, if no special techniques are used in taking CT images. The 3-D heart image is reconstructed from numerous CT images in which both the heart and the lung are taken. Although the outline shape of the reconstructed 3-D heart is quite unnatural, the envelope of the 3-D unnatural heart is fit to the shape of the standard heart. The envelopes of the lung in the CT images are calculated after the section images of the best fitting standard heart are located at the same positions of the CT images. Thus the CT images are geometrically transformed to the optimal CT images fitting best to the standard heart. Since correct transformation of images is required, an Area oriented interpolation method proposed by us is used for interpolation of transformed images. An attempt to reconstruct a 3-D lung image by a series of such operations without discontinuity is shown. Additionally, the same geometrical transformation method to the original projection images is proposed as a more advanced method.

  8. Segmentation-based CT image compression

    Science.gov (United States)

    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.

  9. Proton-induced x-ray fluorescence CT imaging.

    Science.gov (United States)

    Bazalova-Carter, Magdalena; Ahmad, Moiz; Matsuura, Taeko; Takao, Seishin; Matsuo, Yuto; Fahrig, Rebecca; Shirato, Hiroki; Umegaki, Kikuo; Xing, Lei

    2015-02-01

    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. 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(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. A linear relationship between gold pXRF and gold concentration was observed in both experimental and MC simulation data (R(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. Proton-induced x-ray fluorescence CT imaging of 3%-5% gold solutions in a small animal sized water phantom has been demonstrated

  10. Proton-induced x-ray fluorescence CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bazalova-Carter, Magdalena, E-mail: bazalova@stanford.edu; Xing, Lei [Department of Radiation Oncology, Stanford University, Stanford, California 94305-5847 and Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo 060-8648 (Japan); Ahmad, Moiz [Department of Radiation Oncology, Stanford University, Stanford, California 94305-5847 (United States); Matsuura, Taeko; Takao, Seishin; Shirato, Hiroki; Umegaki, Kikuo [Department of Medical Physics, Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo 060-8648, Japan and Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo 060-8648 (Japan); Matsuo, Yuto [Department of Medical Physics, Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo 060-8648 (Japan); Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States)

    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

  11. Combined SPECT/CT and PET/CT for breast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Russo, Paolo [Università di Napoli Federico II, Dipartimento di Fisica, Via Cintia, Naples I-80126 (Italy); INFN Sezione di Napoli, Via Cintia, Naples I-80126 (Italy); Larobina, Michele [Istituto di Biostrutture e Bioimmagini, Consiglio Nazionale delle Ricerche, Via Tommaso De Amicis, 95, Naples I-80145 (Italy); Di Lillo, Francesca [Università di Napoli Federico II, Dipartimento di Fisica, Via Cintia, Naples I-80126 (Italy); INFN Sezione di Napoli, Via Cintia, Naples I-80126 (Italy); Del Vecchio, Silvana [Università di Napoli Federico II, Dipartimento di Scienze Biomediche Avanzate, Via Pansini, 5, Naples I-80131 (Italy); Mettivier, Giovanni, E-mail: mettivier@na.infn.it [Università di Napoli Federico II, Dipartimento di Fisica, Via Cintia, Naples I-80126 (Italy); INFN Sezione di Napoli, Via Cintia, Naples I-80126 (Italy)

    2016-02-11

    In the field of nuclear medicine imaging, breast imaging for cancer diagnosis is still mainly based on 2D imaging techniques. Three-dimensional tomographic imaging with whole-body PET or SPECT scanners, when used for imaging the breast, has performance limits in terms of spatial resolution and sensitivity, which can be overcome only with a dedicated instrumentation. However, only few hybrid imaging systems for PET/CT or SPECT/CT dedicated to the breast have been developed in the last decade, providing complementary functional and anatomical information on normal breast tissue and lesions. These systems are still under development and clinical trials on just few patients have been reported; no commercial dedicated breast PET/CT or SPECT/CT is available. This paper reviews combined dedicated breast PET/CT and SPECT/CT scanners described in the recent literature, with focus on their technological aspects.

  12. Automatic segmentation of bladder in CT images

    Institute of Scientific and Technical Information of China (English)

    Feng SHI; Jie YANG; Yue-min ZHU

    2009-01-01

    Segmentation of the bladder in computerized tomography (CT) images is an important step in radiation therapy planning of prostate cancer. We present a new segmentation scheme to automatically delineate the bladder contour in CT images with three major steps. First, we use the mean shift algorithm to obtain a clustered image containing the rough contour of the bladder, which is then extracted in the second step by applying a region-growing algorithm with the initial seed point selected from a line-by-line scanning process. The third step is to refine the bladder contour more accurately using the rolling-ball algorithm. These steps are then extended to segment the bladder volume in a slice-by-slice manner. The obtained results were compared to manual segmentation by radiation oncologists. The average values of sensitivity, specificity, positive predictive value, negative predictive value, and Hausdorff distance are 86.5%, 96.3%, 90.5%, 96.5%, and 2.8 pixels, respectively. The results show that the bladder can be accurately segmented.

  13. Automatic segmentation of lumbar vertebrae in CT images

    Science.gov (United States)

    Kulkarni, Amruta; Raina, Akshita; Sharifi Sarabi, Mona; Ahn, Christine S.; Babayan, Diana; Gaonkar, Bilwaj; Macyszyn, Luke; Raghavendra, Cauligi

    2017-03-01

    Lower back pain is one of the most prevalent disorders in the developed/developing world. However, its etiology is poorly understood and treatment is often determined subjectively. In order to quantitatively study the emergence and evolution of back pain, it is necessary to develop consistently measurable markers for pathology. Imaging based measures offer one solution to this problem. The development of imaging based on quantitative biomarkers for the lower back necessitates automated techniques to acquire this data. While the problem of segmenting lumbar vertebrae has been addressed repeatedly in literature, the associated problem of computing relevant biomarkers on the basis of the segmentation has not been addressed thoroughly. In this paper, we propose a Random-Forest based approach that learns to segment vertebral bodies in CT images followed by a biomarker evaluation framework that extracts vertebral heights and widths from the segmentations obtained. Our dataset consists of 15 CT sagittal scans obtained from General Electric Healthcare. Our main approach is divided into three parts: the first stage is image pre-processing which is used to correct for variations in illumination across all the images followed by preparing the foreground and background objects from images; the next stage is Machine Learning using Random-Forests, which distinguishes the interest-point vectors between foreground or background; and the last step is image post-processing, which is crucial to refine the results of classifier. The Dice coefficient was used as a statistical validation metric to evaluate the performance of our segmentations with an average value of 0.725 for our dataset.

  14. CT myocardial perfusion imaging: current status and future directions.

    Science.gov (United States)

    Williams, M C; Newby, D E

    2016-08-01

    Computed tomography (CT) imaging of the heart has advanced rapidly, and it is now possible to perform a comprehensive assessment at a low radiation dose. CT myocardial perfusion imaging can provide additive information to CT coronary angiography, and is particularly useful in patients with heavily calcified coronary arteries or coronary artery stents. A number of protocols are now available for CT myocardial perfusion including static, dynamic, and dual-energy techniques. This review will discuss the current status of CT myocardial perfusion imaging, its clinical application, and future directions for this technology.

  15. Cirrhosis: CT and MR imaging evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Brancatelli, Giuseppe [Sezione di Radiologia, Ospedale Specializzato in Gastroenterologia, ' Saverio de Bellis' -IRCCS, 70013 Castellana Grotte (Bari) (Italy) and Sezione di Scienze Radiologiche, Dipartimento di Biotecnologie Mediche e Medicina Legale, Universita di Palermo, Via del Vespro 127, 90127 Palermo (Italy) and Department of Radiology, University of Pittsburgh Medical Center, 200 Lothrop Street, 15213 Pittsburgh, PA (United States)]. E-mail: gbranca@yahoo.com; Federle, Michael P. [Department of Radiology, University of Pittsburgh Medical Center, 200 Lothrop Street, 15213 Pittsburgh, PA (United States); Ambrosini, Roberta [Department of Diagnostic and Interventional Radiology, ' Maggiore della Carita' University Hospital, ' A.Avogadro' Eastern Piemonte University, Corso Mazzini 18, Novara (Italy); Lagalla, Roberto [Sezione di Scienze Radiologiche, Dipartimento di Biotecnologie Mediche e Medicina Legale, Universita di Palermo, Via del Vespro 127, 90127 Palermo (Italy); Carriero, Alessandro [Department of Diagnostic and Interventional Radiology, ' Maggiore della Carita' University Hospital, ' A.Avogadro' Eastern Piemonte University, Corso Mazzini 18, Novara (Italy); Midiri, Massimo [Sezione di Scienze Radiologiche, Dipartimento di Biotecnologie Mediche e Medicina Legale, Universita di Palermo, Via del Vespro 127, 90127 Palermo (Italy); Vilgrain, Valerie [Service de Radiologie, Hopital Beaujon, 100 Boulevard du General Leclerc, 92118 Clichy (France)

    2007-01-15

    In this article, we present the CT and MR imaging characteristics of the cirrhotic liver. We describe the altered liver morphology in different forms of viral, alcoholic and autoimmune end-stage liver disease. We present the spectrum of imaging findings in portal hypertension, such as splenomegaly, ascites and varices. We describe the patchy and lacelike patterns of fibrosis, along with the focal confluent form. The process of hepatocarcinogenesis is detailed, from regenerative to dysplastic nodules to overt hepatocellular carcinoma. Different types of non-neoplastic focal liver lesions occurring in the cirrhotic liver are discussed, including arterially enhancing nodules, hemangiomas and peribiliary cysts. We show different conditions causing liver morphology changes that can mimic cirrhosis, such as congenital hepatic fibrosis, 'pseudo-cirrhosis' due to breast metastases treated with chemotherapy, Budd-Chiari syndrome, sarcoidosis and cavernous transformation of the portal vein.

  16. Abdominal wall hernias: imaging with spiral CT

    Energy Technology Data Exchange (ETDEWEB)

    Stabile Ianora, A.A.; Midiri, M.; Vinci, R.; Rotondo, A.; Angelelli, G. [Department of Radiology, Bari University Hospital (Italy)

    2000-06-01

    Computed tomography is an accurate method of identifying the various types of abdominal wall hernias, especially if they are clinically occult, and of distinguishing them from other diseases such as hematomas, abscesses and neoplasia. In this study we examined the CT images of 94 patients affected by abdominal wall hernias observed over a period of 6 years. Computed tomography clearly demonstrates the anatomical site of the hernial sac, the content and any occlusive bowel complications due to incarceration or strangulation. Clinical diagnosis of external hernias is particularly difficult in obese patients or in those with laparotic scars. In these cases abdominal imaging is essential for a correct preoperative diagnosis and to determine the most effective treatment. (orig.)

  17. A microPET/CT system for invivo small animal imaging

    Science.gov (United States)

    Liang, H.; Yang, Y.; Yang, K.; Wu, Y.; Boone, J. M.; Cherry, S. R.

    2007-07-01

    A microCT scanner was designed, fabricated and integrated with a previously reported microPET II scanner (Tai et al 2003 Phys. Med. Biol. 48 1519, Yang et al 2004 Phys. Med. Biol. 49 2527), forming a dual modality system for in vivo anatomic and molecular imaging of the mouse. The system was designed to achieve high-spatial-resolution and high-sensitivity PET images with adequate CT image quality for anatomic localization and attenuation correction with low x-ray dose. The system also has relatively high throughput for screening, and a flexible gantry and user interface. X-rays were produced by a 50 kVp, 1.5 mA fixed tungsten anode tube, with a focal spot size of 70 µm. The detector was a 5 × 5 cm2 photodiode detector incorporating 48 µm pixels on a CMOS array and a fast gadolinium oxysulfide (GOS) intensifying screen. The microCT system has a flexible C-arm gantry design with adjustable detector positioning, which acquires CT projection images around the common microPET/CT bed. The design and the initial characterization of the microCT system is described, and images of the first mouse scans with microPET/CT scanning protocols are shown.

  18. A microPET/CT system for invivo small animal imaging

    Energy Technology Data Exchange (ETDEWEB)

    Liang, H [Department of Biomedical Engineering, University of California, Davis, GBSF Building, 451 East Health Sciences Drive, Davis, CA 95616 (United States); Yang, Y [Department of Biomedical Engineering, University of California, Davis, GBSF Building, 451 East Health Sciences Drive, Davis, CA 95616 (United States); Yang, K [Department of Radiology, UC Davis Medical Center, 4701 X Street, X-ray Imaging Laboratory, Sacramento, CA 95817 (United States); Wu, Y [Department of Biomedical Engineering, University of California, Davis, GBSF Building, 451 East Health Sciences Drive, Davis, CA 95616 (United States); Boone, J M [Department of Biomedical Engineering, University of California, Davis, GBSF Building, 451 East Health Sciences Drive, Davis, CA 95616 (United States); Cherry, S R [Department of Biomedical Engineering, University of California, Davis, GBSF Building, 451 East Health Sciences Drive, Davis, CA 95616 (United States)

    2007-07-07

    A microCT scanner was designed, fabricated and integrated with a previously reported microPET II scanner (Tai et al 2003 Phys. Med. Biol. 48 1519, Yang et al 2004 Phys. Med. Biol. 49 2527), forming a dual modality system for in vivo anatomic and molecular imaging of the mouse. The system was designed to achieve high-spatial-resolution and high-sensitivity PET images with adequate CT image quality for anatomic localization and attenuation correction with low x-ray dose. The system also has relatively high throughput for screening, and a flexible gantry and user interface. X-rays were produced by a 50 kVp, 1.5 mA fixed tungsten anode tube, with a focal spot size of 70 {mu}m. The detector was a 5 x 5 cm{sup 2} photodiode detector incorporating 48 {mu}m pixels on a CMOS array and a fast gadolinium oxysulfide (GOS) intensifying screen. The microCT system has a flexible C-arm gantry design with adjustable detector positioning, which acquires CT projection images around the common microPET/CT bed. The design and the initial characterization of the microCT system is described, and images of the first mouse scans with microPET/CT scanning protocols are shown.

  19. Neural network and its application to CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Nikravesh, M.; Kovscek, A.R.; Patzek, T.W. [Lawrence Berkeley National Lab., CA (United States)] [and others

    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.

  20. Evaluation of electrode position in deep brain stimulation by image fusion (MRI and CT)

    Energy Technology Data Exchange (ETDEWEB)

    Barnaure, I.; Lovblad, K.O.; Vargas, M.I. [Geneva University Hospital, Department of Neuroradiology, Geneva 14 (Switzerland); Pollak, P.; Horvath, J.; Boex, C.; Burkhard, P. [Geneva University Hospital, Department of Neurology, Geneva (Switzerland); Momjian, S. [Geneva University Hospital, Department of Neurosurgery, Geneva (Switzerland); Remuinan, J. [Geneva University Hospital, Department of Radiology, Geneva (Switzerland)

    2015-09-15

    Imaging has an essential role in the evaluation of correct positioning of electrodes implanted for deep brain stimulation (DBS). Although MRI offers superior anatomic visualization of target sites, there are safety concerns in patients with implanted material; imaging guidelines are inconsistent and vary. The fusion of postoperative CT with preoperative MRI images can be an alternative for the assessment of electrode positioning. The purpose of this study was to assess the accuracy of measurements realized on fused images (acquired without a stereotactic frame) using a manufacturer-provided software. Data from 23 Parkinson's disease patients who underwent bilateral electrode placement for subthalamic nucleus (STN) DBS were acquired. Preoperative high-resolution T2-weighted sequences at 3 T, and postoperative CT series were fused using a commercially available software. Electrode tip position was measured on the obtained images in three directions (in relation to the midline, the AC-PC line and an AC-PC line orthogonal, respectively) and assessed in relation to measures realized on postoperative 3D T1 images acquired at 1.5 T. Mean differences between measures carried out on fused images and on postoperative MRI lay between 0.17 and 0.97 mm. Fusion of CT and MRI images provides a safe and fast technique for postoperative assessment of electrode position in DBS. (orig.)

  1. An approach for quantitative image quality analysis for CT

    Science.gov (United States)

    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.

  2. Automated vertebra identification in CT images

    Science.gov (United States)

    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.

  3. In vivo microCT imaging of rodent cerebral vasculature

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Youngho; Hasegawa, Bruce H [Center for Molecular and Functional Imaging, Department of Radiology, University of California, San Francisco, CA 94143 (United States); Hashimoto, Tomoki; Nuki, Yoshitsugu [Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA 94143 (United States)], E-mail: youngho.seo@radiology.ucsf.edu

    2008-04-07

    Computed tomography (CT) remains a critical diagnostic tool for evaluating patients with cerebrovascular disease, and the advent of specialized systems for imaging rodents has extended these techniques to small animal models of these diseases. We therefore have evaluated in vivo methods of imaging rat models of hemorrhagic stroke using a high resolution compact computed tomography ('microCT') system (FLEX(tm) X-O(tm), Gamma Medica-Ideas, Northridge, CA). For all in vivo studies, the head of the anesthetized rat was secured in a custom immobilization device for microCT imaging with 512 projections over 2 min at 60 kVp and 0.530 mA (I{sub tube} x t/rotation = 63.6 mAs). First, imaging without iodinated contrast was performed (a) to differentiate the effect of contrast agent in contrast-enhanced CT and (b) to examine the effectiveness of the immobilization device between two time points of CT acquisitions. Then, contrast-enhanced CT was performed with continuous administration of iopromide (300 mgI ml{sup -1} at 1.2 ml min{sup -1}) to visualize aneurysms and other vascular formations in the carotid and cerebral arteries that may precede subarachnoid hemorrhage. The accuracy of registration between the noncontrast and contrast-enhanced CT images with the immobilization device was compared against the images aligned with normalized mutual information using FMRIB's linear image registration tool (FLIRT). Translations and rotations were examined between the FLIRT-aligned noncontrast CT image and the nonaligned noncontrast CT image. These two data sets demonstrated translational and rotational differences of less than 0.5 voxel ({approx}85 {mu}m) and 0.5 deg., respectively. Noncontrast CT demonstrated a very small volume (0.1 ml) of femoral arterial blood introduced surgically into the rodent brain. Continuous administration of iopromide during the CT acquisition produced consistent vascular contrast in the reconstructed CT images. As a result, carotid

  4. Comparison of Image Registration Based Measures of Regional Lung Ventilation from Dynamic Spiral CT with Xe-CT

    CERN Document Server

    Ding, Kai; Fuld, Matthew K; Du, Kaifang; Christensen, Gary E; Hoffman, Eric A; Reinhardt, Joseph M

    2012-01-01

    Purpose: Regional lung volume change as a function of lung inflation serves as an index of parenchymal and airway status as well as an index of regional ventilation and can be used to detect pathologic changes over time. In this article, we propose a new regional measure of lung mechanics --- the specific air volume change by corrected Jacobian. Methods: 4DCT and Xe-CT data sets from four adult sheep are used in this study. Nonlinear, 3D image registration is applied to register an image acquired near end inspiration to an image acquired near end expiration. Approximately 200 annotated anatomical points are used as landmarks to evaluate registration accuracy. Three different registration-based measures of regional lung mechanics are derived and compared: the specific air volume change calculated from the Jacobian (SAJ); the specific air volume change calculated by the corrected Jacobian (SACJ); and the specific air volume change by intensity change (SAI). Results: After registration, the mean registration err...

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

    Science.gov (United States)

    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

  6. Image quality assessment of a pre-clinical flat-panel volumetric micro-CT scanner

    Science.gov (United States)

    Du, Louise Y.; Lee, Ting-Yim; Holdsworth, David W.

    2006-03-01

    Small animal imaging has recently become an area of increased interest because more human diseases can be modeled in transgenic and knockout rodents. Current micro-CT systems are capable of achieving spatial resolution on the order of 10 μm, giving highly detailed anatomical information. However, the speed of data acquisition of these systems is relatively slow, when compared with clinical CT systems. Dynamic CT perfusion imaging has proven to be a powerful tool clinically in detecting and diagnosing cancer, stroke, pulmonary and ischemic heart diseases. In order to perform this technique in mice and rats, quantitative CT images must be acquired at a rate of at least 1 Hz. Recently, a research pre-clinical CT scanner (eXplore Ultra, GE Healthcare) has been designed specifically for dynamic perfusion imaging in small animals. Using an amorphous silicon flat-panel detector and a clinical slip-ring gantry, this system is capable of acquiring volumetric image data at a rate of 1 Hz, with in-plane resolution of 150 μm, while covering the entire thoracic region of a mouse or whole organs of a rat. The purpose of this study was to evaluate the principal imaging performance of the micro-CT system, in terms of spatial resolution, image uniformity, linearity, dose and voxel noise for the feasibility of imaging mice and rats. Our investigations show that 3D images can be obtained with a limiting spatial resolution of 2.7 line pairs per mm and noise of 42 HU, using an acquisition interval of 8 seconds at an entrance dose of 6.4 cGy.

  7. Evaluation of GMI and PMI diffeomorphic-based demons algorithms for aligning PET and CT Images.

    Science.gov (United States)

    Yang, Juan; Wang, Hongjun; Zhang, You; Yin, Yong

    2015-07-08

    Fusion of anatomic information in computed tomography (CT) and functional information in 18F-FDG positron emission tomography (PET) is crucial for accurate differentiation of tumor from benign masses, designing radiotherapy treatment plan and staging of cancer. Although current PET and CT images can be acquired from combined 18F-FDG PET/CT scanner, the two acquisitions are scanned separately and take a long time, which may induce potential positional errors in global and local caused by respiratory motion or organ peristalsis. So registration (alignment) of whole-body PET and CT images is a prerequisite for their meaningful fusion. The purpose of this study was to assess the performance of two multimodal registration algorithms for aligning PET and CT images. The proposed gradient of mutual information (GMI)-based demons algorithm, which incorporated the GMI between two images as an external force to facilitate the alignment, was compared with the point-wise mutual information (PMI) diffeomorphic-based demons algorithm whose external force was modified by replacing the image intensity difference in diffeomorphic demons algorithm with the PMI to make it appropriate for multimodal image registration. Eight patients with esophageal cancer(s) were enrolled in this IRB-approved study. Whole-body PET and CT images were acquired from a combined 18F-FDG PET/CT scanner for each patient. The modified Hausdorff distance (d(MH)) was used to evaluate the registration accuracy of the two algorithms. Of all patients, the mean values and standard deviations (SDs) of d(MH) were 6.65 (± 1.90) voxels and 6.01 (± 1.90) after the GMI-based demons and the PMI diffeomorphic-based demons registration algorithms respectively. Preliminary results on oncological patients showed that the respiratory motion and organ peristalsis in PET/CT esophageal images could not be neglected, although a combined 18F-FDG PET/CT scanner was used for image acquisition. The PMI diffeomorphic-based demons

  8. Reduction of beam hardening artifacts in cone-beam CT imaging via SMART-RECON algorithm

    Science.gov (United States)

    Li, Yinsheng; Garrett, John; Chen, Guang-Hong

    2016-03-01

    When an automatic exposure control is introduced in C-arm cone beam CT data acquisition, the spectral inconsistencies between acquired projection data are exacerbated. As a result, conventional water/bone correction schemes are not as effective as in conventional diagnostic x-ray CT acquisitions with a fixed tube potential. In this paper, a new method was proposed to reconstruct several images with different degrees of spectral consistency and thus different levels of beam hardening artifacts. The new method relies neither on prior knowledge of the x-ray beam spectrum nor on prior compositional information of the imaging object. Numerical simulations were used to validate the algorithm.

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

    Science.gov (United States)

    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

  10. Dose calculation based on Cone Beam CT images

    DEFF Research Database (Denmark)

    Slot Thing, Rune

    , several other factors contributing to the image quality degradation, and while one should, theoretically, be able to obtain CT-like image quality from CBCT scans, clinical image quality is often very far from this ideal realisation. The present thesis describes the investigation of potential image quality...... improvements in clinical CBCT imaging achieved through post-processing of the clinical image data. A Monte Carlo model was established to predict patient specific scattered radiation in CBCT imaging, based on anatomical information from the planning CT scan. This allowed the time consuming Monte Carlo......Cone beam CT (CBCT) imaging is frequently used in modern radiotherapy to ensure the proper positioning of the patient prior to each treatment fraction. With the increasing use of CBCT imaging for image guidance, interest has grown in exploring the potential use of these 3– or 4–D medical images...

  11. AAPM/RSNA physics tutorial for residents: topics in CT. Image processing in CT.

    Science.gov (United States)

    Cody, Dianna D

    2002-01-01

    Several image-processing methods for computed tomographic (CT) examinations are currently being used in clinical radiology departments. Image processing involves operations such as reformatting of original CT images, volume-rendered displays, surface-rendered displays, and physiologic imaging analysis. The reformatting process does not alter the CT voxels in any way; instead it uses them in off-axis views and displays the images produced from the original reconstruction process in an orientation other than how they were originally generated. Sagittal, coronal, oblique, and curved reformatting are standard reformatting methods. Other reformatting techniques include maximum-intensity projection, minimum-intensity projection, and variable thickness viewing. Volume and surface rendering are two different methods for reformatting axial images into three-dimensional views. CT perfusion allows the measurement of physiologic parameters over time. Additional postprocessing efforts can potentially add value to the patients and their outcomes, as can be seen in the cases that illustrate this article.

  12. Personal computer aided cerebral perfusion imaging with dynamic CT

    Institute of Scientific and Technical Information of China (English)

    林燕; 高培毅

    2004-01-01

    @@Reports on the clinical implementation of dynamic computerised tomography (CT) perfusion imaging and quantitative measurement have increased dramatically of late.1-8 The advantages of dynamic CT perfusion imaging and quantitative measurement for the diagnosis of acute cerebral infarction have been acknowledged. However, most overseas CT vendors set perfusion imaging software package as an option for graphic workstation at a too high price for domestic practitioners. To foster the domestic implementation and development of this new technology, we have extended the earlier work.1,2 Applying the theory of central volume principle to DICOM 3.0 standard forms of prime CT images, we developed dynamic CT perfusion imaging and quantitative measure-ment programmes for PCs using Visual C+ + in Windows 98 system.

  13. Fast CT-CT fluoroscopy registration with respiratory motion compensation for image-guided lung intervention

    Science.gov (United States)

    Su, Po; Xue, Zhong; Lu, Kongkuo; Yang, Jianhua; Wong, Stephen T.

    2012-02-01

    CT-fluoroscopy (CTF) is an efficient imaging method for guiding percutaneous lung interventions such as biopsy. During CTF-guided biopsy procedure, four to ten axial sectional images are captured in a very short time period to provide nearly real-time feedback to physicians, so that they can adjust the needle as it is advanced toward the target lesion. Although popularly used in clinics, this traditional CTF-guided intervention procedure may require frequent scans and cause unnecessary radiation exposure to clinicians and patients. In addition, CTF only generates limited slices of images and provides limited anatomical information. It also has limited response to respiratory movements and has narrow local anatomical dynamics. To better utilize CTF guidance, we propose a fast CT-CTF registration algorithm with respiratory motion estimation for image-guided lung intervention using electromagnetic (EM) guidance. With the pre-procedural exhale and inhale CT scans, it would be possible to estimate a series of CT images of the same patient at different respiratory phases. Then, once a CTF image is captured during the intervention, our algorithm can pick the best respiratory phase-matched 3D CT image and performs a fast deformable registration to warp the 3D CT toward the CTF. The new 3D CT image can be used to guide the intervention by superimposing the EM-guided needle location on it. Compared to the traditional repetitive CTF guidance, the registered CT integrates both 3D volumetric patient data and nearly real-time local anatomy for more effective and efficient guidance. In this new system, CTF is used as a nearly real-time sensor to overcome the discrepancies between static pre-procedural CT and the patient's anatomy, so as to provide global guidance that may be supplemented with electromagnetic (EM) tracking and to reduce the number of CTF scans needed. In the experiments, the comparative results showed that our fast CT-CTF algorithm can achieve better registration

  14. Quantitative Analysis of Micro-CT Imaging and Histopathological Signatures of Experimental Arthritis in Rats

    Directory of Open Access Journals (Sweden)

    Matthew D. Silva

    2004-10-01

    Full Text Available Micro-computed tomographic (micro-CT imaging provides a unique opportunity to capture 3-D architectural information in bone samples. In this study of pathological joint changes in a rat model of adjuvant-induced arthritis (AA, quantitative analysis of bone volume and roughness were performed by micro-CT imaging and compared with histopathology methods and paw swelling measurement. Micro-CT imaging of excised rat hind paws (n = 10 stored in formalin consisted of approximately 600 30-μm slices acquired on a 512 × 512 image matrix with isotropic resolution. Following imaging, the joints were scored from H&E stained sections for cartilage/bone erosion, pannus development, inflammation, and synovial hyperplasia. From micro-CT images, quantitative analysis of absolute bone volumes and bone roughness was performed. Bone erosion in the rat AA model is substantial, leading to a significant decline in tarsal volume (27%. The result of the custom bone roughness measurement indicated a 55% increase in surface roughness. Histological and paw volume analyses also demonstrated severe arthritic disease as compared to controls. Statistical analyses indicate correlations among bone volume, roughness, histology, and paw volume. These data demonstrate that the destructive progression of disease in a rat AA model can be quantified using 3-D micro-CT image analysis, which allows assessment of arthritic disease status and efficacy of experimental therapeutic agents.

  15. Rare Thyroid Cartilage and Diaphragm Metastases from Lung Cancer Visualized on F-18 FDG-PET/CT Imaging

    Directory of Open Access Journals (Sweden)

    Pelin Özcan Kara

    2011-08-01

    Full Text Available Positron emission tomography (PET with F-18 fluorodeoxyglucose (FDG has evolved as a useful imaging modality in the assessment of a variety of cancers, especially for tumor staging and post treatment monitoring. It provides metabolic information. Although, when used alone, relative lack of anatomic landmarks, is a major limitation of PET imaging, this limitation of PET imaging is overcome by the availability of integrated PET/CT imaging. PET and CT images are acquired in one procedure, yielding fused anatomical and functional data sets. Studies with integrated PET/CT imaging have shown promising results. In this case, we present an interesting integrated PET/CT imaging in a lung cancer patient with rare, diaphragm and thyroid cartilage metastases. (MIRT 2011;20:70-72

  16. Reduction of Cone-Beam CT scan time without compromising the accuracy of the image registration in IGRT

    DEFF Research Database (Denmark)

    Westberg, Jonas; Jensen, Henrik R; Bertelsen, Anders;

    2010-01-01

    In modern radiotherapy accelerators are equipped with 3D cone-beam CT (CBCT) which is used to verify patient position before treatment. The verification is based on an image registration between the CBCT acquired just before treatment and the CT scan made for the treatment planning. The purpose...... of this study is to minimise the scan time of the CBCT without compromising the accuracy of the image registration in IGRT....

  17. Dual energy CT: New horizon in medical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Goo, Jin Mo [Dept. of Radiology, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2017-08-01

    Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.

  18. Dual-Energy CT: New Horizon in Medical Imaging.

    Science.gov (United States)

    Goo, Hyun Woo; Goo, Jin Mo

    2017-01-01

    Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    I. Jasmine Selvakumari Jeya

    2015-01-01

    Full Text Available 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.

  1. A minimum spanning forest based classification method for dedicated breast CT images

    Energy Technology Data Exchange (ETDEWEB)

    Pike, Robert [Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia 30329 (United States); Sechopoulos, Ioannis [Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia 30329 and Winship Cancer Institute of Emory University, Atlanta, Georgia 30322 (United States); Fei, Baowei, E-mail: bfei@emory.edu [Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia 30329 (United States); Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, Georgia 30322 (United States); Department of Mathematics and Computer Science, Emory University, Atlanta, Georgia 30322 (United States); Winship Cancer Institute of Emory University, Atlanta, Georgia 30322 (United States)

    2015-11-15

    Purpose: To develop and test an automated algorithm to classify different types of tissue in dedicated breast CT images. Methods: Images of a single breast of five different patients were acquired with a dedicated breast CT clinical prototype. The breast CT images were processed by a multiscale bilateral filter to reduce noise while keeping edge information and were corrected to overcome cupping artifacts. As skin and glandular tissue have similar CT values on breast CT images, morphologic processing is used to identify the skin based on its position information. A support vector machine (SVM) is trained and the resulting model used to create a pixelwise classification map of fat and glandular tissue. By combining the results of the skin mask with the SVM results, the breast tissue is classified as skin, fat, and glandular tissue. This map is then used to identify markers for a minimum spanning forest that is grown to segment the image using spatial and intensity information. To evaluate the authors’ classification method, they use DICE overlap ratios to compare the results of the automated classification to those obtained by manual segmentation on five patient images. Results: Comparison between the automatic and the manual segmentation shows that the minimum spanning forest based classification method was able to successfully classify dedicated breast CT image with average DICE ratios of 96.9%, 89.8%, and 89.5% for fat, glandular, and skin tissue, respectively. Conclusions: A 2D minimum spanning forest based classification method was proposed and evaluated for classifying the fat, skin, and glandular tissue in dedicated breast CT images. The classification method can be used for dense breast tissue quantification, radiation dose assessment, and other applications in breast imaging.

  2. Quantitative image quality evaluation for cardiac CT reconstructions

    Science.gov (United States)

    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.

  3. Automated Segmentation and Retrieval System for CT Head Images

    Science.gov (United States)

    Tong, Hau-Lee; Ahmad Fauzi, Mohammad Faizal; Komiya, Ryoichi

    In this paper, automatic segmentation and retrieval of medical images are presented. For the segmentation, different unsupervised clustering techniques are employed to partition the Computed Tomography (CT) brain images into three regions, which are the abnormalities, cerebrospinal fluids (CSF) and brain matters. The novel segmentation method proposed is a dual level segmentation approach. The first level segmentation, which purpose is to acquire abnormal regions, uses the combination of fuzzy c-means (FCM) and k-means clustering. The second level segmentation performs either the expectation-maximization (EM) technique or the modified FCM with population-diameter independent (PDI) to segment the remaining intracranial area into CSF and brain matters. The system automatically determines which algorithm to be utilized in order to produce optimum results. The retrieval of the medical images is based on keywords such as "no abnormal region", "abnormal region(s) adjacent to the skull" and "abnormal region(s) not adjacent to the skull". Medical data from collaborating hospital are experimented and promising results are observed.

  4. Robust cranial cavity segmentation in CT and CT perfusion images of trauma and suspected stroke patients

    NARCIS (Netherlands)

    Patel, A; Ginneken, B. van; Meijer, F.J.A.; Dijk, E.J. van; Prokop, M.; Manniesing, R.

    2017-01-01

    A robust and accurate method is presented for the segmentation of the cranial cavity in computed tomography (CT) and CT perfusion (CTP) images. The method consists of multi-atlas registration with label fusion followed by a geodesic active contour levelset refinement of the segmentation.

  5. A New Method of CT MedicalImages Contrast Enhancement

    Institute of Scientific and Technical Information of China (English)

    SUNFeng-rong; LIUWei; WANGChang-yu; MEILiang-mo

    2004-01-01

    A new method of contrast enhancement is proposed in the paper using multiscale edge representation of images, and is applied to the field of CT medical image processing. Comparing to the traditional Window technique, our method is adaptive and meets the demand of radiology clinics more better. The clinical experiment results show the practicality and the potential applied value of our methodin the field of CT medical images contrast enhancement.

  6. SPECT/CT imaging in children with papillary thyroid carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hwa-Young; Gelfand, Michael J.; Sharp, Susan E. [Cincinnati Children' s Hospital, Department of Radiology, Cincinnati, OH (United States)

    2011-08-15

    SPECT/CT improves localization of single photon-emitting radiopharmaceuticals. To determine the utility of SPECT/CT in children with papillary thyroid carcinoma. 20 SPECT/CT and planar studies were reviewed in 13 children with papillary thyroid carcinoma after total thyroidectomy. Seven studies used I-123 and 13 used I-131, after elevating TSH by T4 deprivation or intramuscular thyrotropin alfa. Eight children had one study and five children had two to four studies. Studies were performed at initial post-total thyroidectomy evaluation, follow-up and after I-131 treatment doses. SPECT/CT was performed with a diagnostic-quality CT unit in 13 studies and a localization-only CT unit in 7. Stimulated thyroglobulin was measured (except in 2 cases with anti-thyroglobulin antibodies). In 13 studies, neck activity was present but poorly localized on planar imaging; all foci of uptake were precisely localized by SPECT/CT. Two additional foci of neck uptake were found on SPECT/CT. SPECT/CT differentiated high neck uptake from facial activity. In six studies (four children), neck uptake was identified as benign by SPECT/CT (three thyroglossal duct remnants, one skin contamination, two by precise anatomical CT localization). In two children, SPECT/CT supported a decision not to treat with I-131. When SPECT/CT was unable to identify focal uptake as benign, stimulated thyroglobulin measurements were valuable. In three of 13 studies with neck uptake, SPECT/CT provided no useful additional information. SPECT/CT precisely localizes neck iodine uptake. In small numbers of patients, treatment is affected. SPECT/CT should be used when available in thyroid carcinoma patients. (orig.)

  7. Multimodal CT in stroke imaging: new concepts.

    Science.gov (United States)

    Ledezma, Carlos J; Wintermark, Max

    2009-01-01

    A multimodal CT protocol provides a comprehensive noninvasive survey of acute stroke patients with accurate demonstration of the site of arterial occlusion and its hemodynamic tissue status. It combines widespread availability with the ability to provide functional characterization of cerebral ischemia, and could potentially allow more accurate selection of candidates for acute stroke reperfusion therapy. This article discusses the individual components of multimodal CT and addresses the potential role of a combined multimodal CT stroke protocol in acute stroke therapy.

  8. Method to acquire regions of fruit, branch and leaf from image of red apple in orchard

    Science.gov (United States)

    Lv, Jidong; Xu, Liming

    2017-07-01

    This work proposed a method to acquire regions of fruit, branch and leaf from red apple image in orchard. To acquire fruit image, R-G image was extracted from the RGB image for corrosive working, hole filling, subregion removal, expansive working and opening operation in order. Finally, fruit image was acquired by threshold segmentation. To acquire leaf image, fruit image was subtracted from RGB image before extracting 2G-R-B image. Then, leaf image was acquired by subregion removal and threshold segmentation. To acquire branch image, dynamic threshold segmentation was conducted in the R-G image. Then, the segmented image was added to fruit image to acquire adding fruit image which was subtracted from RGB image with leaf image. Finally, branch image was acquired by opening operation, subregion removal and threshold segmentation after extracting the R-G image from the subtracting image. Compared with previous methods, more complete image of fruit, leaf and branch can be acquired from red apple image with this method.

  9. Whole-brain dynamic CT angiography and perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Orrison, W.W. [CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Department of Medical Education, University of Nevada School of Medicine, Reno, NV (United States); Snyder, K.V.; Hopkins, L.N. [Department of Neurosurgery, Millard Fillmore Gates Circle Hospital, Buffalo, NY (United States); Roach, C.J. [School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); Ringdahl, E.N. [Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV (United States); Nazir, R. [Shifa International Hospital, Islamabad (Pakistan); Hanson, E.H., E-mail: eric.hanson@amigenics.co [College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States)

    2011-06-15

    The availability of whole brain computed tomography (CT) perfusion has expanded the opportunities for analysing the haemodynamic parameters associated with varied neurological conditions. Examples demonstrating the clinical utility of whole-brain CT perfusion imaging in selected acute and chronic ischaemic arterial neurovascular conditions are presented. Whole-brain CT perfusion enables the detection and focused haemodynamic analyses of acute and chronic arterial conditions in the central nervous system without the limitation of partial anatomical coverage of the brain.

  10. D Model Generation Using Oblique Images Acquired by Uav

    Science.gov (United States)

    Lingua, A.; Noardo, F.; Spanò, A.; Sanna, S.; Matrone, F.

    2017-07-01

    In recent years, many studies revealed the advantages of using airborne oblique images for obtaining improved 3D city models (including façades and building footprints). Here the acquisition and use of oblique images from a low cost and open source Unmanned Aerial Vehicle (UAV) for the 3D high-level-of-detail reconstruction of historical architectures is evaluated. The critical issues of such acquisitions (flight planning strategies, ground control points distribution, etc.) are described. Several problems should be considered in the flight planning: best approach to cover the whole object with the minimum time of flight; visibility of vertical structures; occlusions due to the context; acquisition of all the parts of the objects (the closest and the farthest) with similar resolution; suitable camera inclination, and so on. In this paper a solution is proposed in order to acquire oblique images with one only flight. The data processing was realized using Structure-from-Motion-based approach for point cloud generation using dense image-matching algorithms implemented in an open source software. The achieved results are analysed considering some check points and some reference LiDAR data. The system was tested for surveying a historical architectonical complex: the "Sacro Mo nte di Varallo Sesia" in north-west of Italy. This study demonstrates that the use of oblique images acquired from a low cost UAV system and processed through an open source software is an effective methodology to survey cultural heritage, characterized by limited accessibility, need for detail and rapidity of the acquisition phase, and often reduced budgets.

  11. Automated Selection of Uniform Regions for CT Image Quality Detection

    CERN Document Server

    Naeemi, Maitham D; Roychodhury, Sohini

    2016-01-01

    CT images are widely used in pathology detection and follow-up treatment procedures. Accurate identification of pathological features requires diagnostic quality CT images with minimal noise and artifact variation. In this work, a novel Fourier-transform based metric for image quality (IQ) estimation is presented that correlates to additive CT image noise. In the proposed method, two windowed CT image subset regions are analyzed together to identify the extent of variation in the corresponding Fourier-domain spectrum. The two square windows are chosen such that their center pixels coincide and one window is a subset of the other. The Fourier-domain spectral difference between these two sub-sampled windows is then used to isolate spatial regions-of-interest (ROI) with low signal variation (ROI-LV) and high signal variation (ROI-HV), respectively. Finally, the spatial variance ($var$), standard deviation ($std$), coefficient of variance ($cov$) and the fraction of abdominal ROI pixels in ROI-LV ($\

  12. Investigating CT to CBCT image registration for head and neck proton therapy as a tool for daily dose recalculation

    Energy Technology Data Exchange (ETDEWEB)

    Landry, Guillaume, E-mail: g.landry@lmu.de [Department of Medical Physics, Ludwig-Maximilians-University, Munich D85748, Germany and Department of Radiation Oncology, Ludwig-Maximilians-University, Munich D81377 (Germany); Nijhuis, Reinoud; Thieke, Christian; Reiner, Michael; Ganswindt, Ute; Belka, Claus [Department of Radiation Oncology, Ludwig-Maximilians-University, Munich D81377 (Germany); Dedes, George; Handrack, Josefine; Parodi, Katia [Department of Medical Physics, Ludwig-Maximilians-University, Munich D85748 (Germany); Janssens, Guillaume; Orban de Xivry, Jonathan [ICTEAM, Université Catholique de Louvain, Louvain-La-Neuve B1348 (Belgium); Kamp, Florian; Wilkens, Jan J. [Department of Radiation Oncology, Technische Universität München, Klinikum rechts der Isar, Munich D81675, Germany and Physik-Department, Technische Universität München, Garching D85748 (Germany); Paganelli, Chiara; Riboldi, Marco; Baroni, Guido [Dipartimento di Elettronica Informazione e Bioingegneria, Politecnico di Milano, Milan 20133 (Italy)

    2015-03-15

    Purpose: Intensity modulated proton therapy (IMPT) of head and neck (H and N) cancer patients may be improved by plan adaptation. The decision to adapt the treatment plan based on a dose recalculation on the current anatomy requires a diagnostic quality computed tomography (CT) scan of the patient. As gantry-mounted cone beam CT (CBCT) scanners are currently being offered by vendors, they may offer daily or weekly updates of patient anatomy. CBCT image quality may not be sufficient for accurate proton dose calculation and it is likely necessary to perform CBCT CT number correction. In this work, the authors investigated deformable image registration (DIR) of the planning CT (pCT) to the CBCT to generate a virtual CT (vCT) to be used for proton dose recalculation. Methods: Datasets of six H and N cancer patients undergoing photon intensity modulated radiation therapy were used in this study to validate the vCT approach. Each dataset contained a CBCT acquired within 3 days of a replanning CT (rpCT), in addition to a pCT. The pCT and rpCT were delineated by a physician. A Morphons algorithm was employed in this work to perform DIR of the pCT to CBCT following a rigid registration of the two images. The contours from the pCT were deformed using the vector field resulting from DIR to yield a contoured vCT. The DIR accuracy was evaluated with a scale invariant feature transform (SIFT) algorithm comparing automatically identified matching features between vCT and CBCT. The rpCT was used as reference for evaluation of the vCT. The vCT and rpCT CT numbers were converted to stopping power ratio and the water equivalent thickness (WET) was calculated. IMPT dose distributions from treatment plans optimized on the pCT were recalculated with a Monte Carlo algorithm on the rpCT and vCT for comparison in terms of gamma index, dose volume histogram (DVH) statistics as well as proton range. The DIR generated contours on the vCT were compared to physician-drawn contours on the rpCT

  13. Functional imaging of the lung by CT und MRI; Funktionelle Lungendiagnostik mit CT und MRT

    Energy Technology Data Exchange (ETDEWEB)

    Puderbach, M.; Eichinger, M.; Kauczor, H.U. [Deutsches Krebsforschungsinstitut Heidelberg (Germany). Abt. Radiologie

    2005-06-01

    Imaging techniques are indispensable for diagnosis and follow-up of pulmonary diseases. In the past the interest was focused on morphological aspects of pulmonary tissue. With the development of novel CT and MRI techniques functional pulmonary imaging became available. In this review the value of cross sectional functional imaging in pulmonary diseases is presented and its potential clinical applications are discussed. (orig.)

  14. Noise spatial nonuniformity and the impact of statistical image reconstruction in CT myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lauzier, Pascal Theriault; Tang Jie; Speidel, Michael A.; Chen Guanghong [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705-2275 (United States); Department of Medical Physics and Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin 53705-2275 (United States)

    2012-07-15

    Purpose: To achieve high temporal resolution in CT myocardial perfusion imaging (MPI), images are often reconstructed using filtered backprojection (FBP) algorithms from data acquired within a short-scan angular range. However, the variation in the central angle from one time frame to the next in gated short scans has been shown to create detrimental partial scan artifacts when performing quantitative MPI measurements. This study has two main purposes. (1) To demonstrate the existence of a distinct detrimental effect in short-scan FBP, i.e., the introduction of a nonuniform spatial image noise distribution; this nonuniformity can lead to unexpectedly high image noise and streaking artifacts, which may affect CT MPI quantification. (2) To demonstrate that statistical image reconstruction (SIR) algorithms can be a potential solution to address the nonuniform spatial noise distribution problem and can also lead to radiation dose reduction in the context of CT MPI. Methods: Projection datasets from a numerically simulated perfusion phantom and an in vivo animal myocardial perfusion CT scan were used in this study. In the numerical phantom, multiple realizations of Poisson noise were added to projection data at each time frame to investigate the spatial distribution of noise. Images from all datasets were reconstructed using both FBP and SIR reconstruction algorithms. To quantify the spatial distribution of noise, the mean and standard deviation were measured in several regions of interest (ROIs) and analyzed across time frames. In the in vivo study, two low-dose scans at tube currents of 25 and 50 mA were reconstructed using FBP and SIR. Quantitative perfusion metrics, namely, the normalized upslope (NUS), myocardial blood volume (MBV), and first moment transit time (FMT), were measured for two ROIs and compared to reference values obtained from a high-dose scan performed at 500 mA. Results: Images reconstructed using FBP showed a highly nonuniform spatial distribution

  15. CT x-ray tube voltage optimisation and image reconstruction evaluation using visual grading analysis

    Science.gov (United States)

    Zheng, Xiaoming; Kim, Ted M.; Davidson, Rob; Lee, Seongju; Shin, Cheongil; Yang, Sook

    2014-03-01

    The purposes of this work were to find an optimal x-ray voltage for CT imaging and to determine the diagnostic effectiveness of image reconstruction techniques by using the visual grading analysis (VGA). Images of the PH-5 CT abdomen phantom (Kagaku Co, Kyoto) were acquired by the Toshiba Aquillion One 320 slices CT system with various exposures (from 10 to 580 mAs) under different tube peak voltages (80, 100 and 120 kVp). The images were reconstructed by employing the FBP and the AIDR 3D iterative reconstructions with Mild, Standard and Strong FBP blending. Image quality was assessed by measuring noise, contrast to noise ratio and human observer's VGA scores. The CT dose index CTDIv was obtained from the values displayed on the images. The best fit for the curves of the image quality VGA vs dose CTDIv is a logistic function from the SPSS estimation. A threshold dose Dt is defined as the CTDIv at the just acceptable for diagnostic image quality and a figure of merit (FOM) is defined as the slope of the standardised logistic function. The Dt and FOM were found to be 5.4, 8.1 and 9.1 mGy and 0.47, 0.51 and 0.38 under the tube voltages of 80, 100 and 120 kVp, respectively, from images reconstructed by the FBP technique. The Dt and FOM values were lower from the images reconstructed by the AIDR 3D in comparison with the FBP technique. The optimal xray peak voltage for the imaging of the PH-5 abdomen phantom by the Aquillion One CT system was found to be at 100 kVp. The images reconstructed by the FBP are more diagnostically effective than that by the AIDR 3D but with a higher dose Dt to the patients.

  16. Computer-aided diagnosis workstation and database system for chest diagnosis based on multihelical CT images

    Science.gov (United States)

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

    2004-04-01

    Lung cancer is the most common cause, accounting for about 20% of all cancer deaths for males in Japan. Myocardial infarction is also known as a most fearful adult disease. Recently, multi-helical CT scanner advanced remarkably at the speed at which the chest CT images were acquired for screening examination. This screening examination requires a considerable number of images to be read. It is this time-consuming step that makes the use of multi-helical CT for mass screening. To overcome this problem, our group has developed a computer-aided diagnosis algorithm to automatically detect suspicious regions of lung cancer and coronary calcifications in chest CT images, so far. And in this time, our group has developed a newly computer-aided diagnosis workstation and database. These consist in three. First, it is an image processing system to automatically detect suspicious bronchial regions, pulmonary artery regions, plumonary vein regions and myocardial infarction regions at high speed. Second, they are two 1600 x 1200 matrix black and white liquid crystal monitor. Third, it is a terminal of image storage. These are connected mutually on the network. This makes it much easier to read images, since the 3D image of suspicious regions and shadow of suspicious regions can be displayed simultaneously on two 1600 x 1200 matrix liquid crystal monitor. The experimental results indicate that a newly computer-aided diagnosis workstation and database system can be effectively used in clinical practice to increase the speed and accuracy of routine diagnosis.

  17. Electronic noise in CT detectors: Impact on image noise and artifacts.

    Science.gov (United States)

    Duan, Xinhui; Wang, Jia; Leng, Shuai; Schmidt, Bernhard; Allmendinger, Thomas; Grant, Katharine; Flohr, Thomas; McCollough, Cynthia H

    2013-10-01

    The objective of our study was to evaluate in phantoms the differences in CT image noise and artifact level between two types of commercial CT detectors: one with distributed electronics (conventional) and one with integrated electronics intended to decrease system electronic noise. Cylindric water phantoms of 20, 30, and 40 cm in diameter were scanned using two CT scanners, one equipped with integrated detector electronics and one with distributed detector electronics. All other scanning parameters were identical. Scans were acquired at four tube potentials and 10 tube currents. Semianthropomorphic phantoms were scanned to mimic the shoulder and abdominal regions. Images of two patients were also selected to show the clinical values of the integrated detector. Reduction of image noise with the integrated detector depended on phantom size, tube potential, and tube current. Scans that had low detected signal had the greatest reductions in noise, up to 40% for a 30-cm phantom scanned using 80 kV. This noise reduction translated into up to 50% in dose reduction to achieve equivalent image noise. Streak artifacts through regions of high attenuation were reduced by up to 45% on scans obtained using the integrated detector. Patient images also showed superior image quality for the integrated detector. For the same applied radiation level, the use of integrated electronics in a CT detector showed a substantially reduced level of electronic noise, resulting in reductions in image noise and artifacts, compared with detectors having distributed electronics.

  18. Ultrasonography Fused with PET-CT Hybrid Imaging

    DEFF Research Database (Denmark)

    Udesen, Jesper; Ewertsen, Caroline; Gran, Fredrik

    2011-01-01

    We present a method with fusion of images of three modalities 18F-FDG PET, CT, and 3-D ultrasound (US) applied to imaging of the anal canal and the rectum. To obtain comparable geometries in the three imaging modalities, a plexiglas rod, with the same dimensions as the US transducer, is placed...... in the anal canal prior to the PET-CT examination. The method is based on manual co-registration of PET-CT images and 3-D US images. The three-modality imaging of the rectum-anal canal may become useful as a supplement to conventional imaging in the external radiation therapy in the treatment of anal cancer......, where the precise delineation of a tumor is crucial to avoid damage from radiation therapy to the healthy tissue surrounding it. The technique is still in a phase of development, and the demands for integration different company software systems are significant before commercial application. Three...

  19. Compartment Syndrome After Varicose Vein Surgery Evidenced by CT Images.

    Science.gov (United States)

    Wang, Sheng-Min; Kim, Maru

    2016-03-01

    A 21-year-old man developed compartment syndrome after a varicose vein surgery. Because of a lack of appropriate diagnostic apparatus, it was not possible to measure calf pressure. The only diagnostic tool available was computed tomography (CT). With the aid of CT, faster diagnosis of the compartment syndrome was possible, leading to appropriate management. By providing unique CT images of a patient before and after having compartment syndrome and after a fasciotomy, this study could add valuable references for diagnosis of compartment syndrome using CT. © The Author(s) 2014.

  20. Volumetric CT-images improve testing of radiological image interpretation skills

    Energy Technology Data Exchange (ETDEWEB)

    Ravesloot, Cécile J., E-mail: C.J.Ravesloot@umcutrecht.nl [Radiology Department at University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht, Room E01.132 (Netherlands); Schaaf, Marieke F. van der, E-mail: M.F.vanderSchaaf@uu.nl [Department of Pedagogical and Educational Sciences at Utrecht University, Heidelberglaan 1, 3584 CS Utrecht (Netherlands); Schaik, Jan P.J. van, E-mail: J.P.J.vanSchaik@umcutrecht.nl [Radiology Department at University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht, Room E01.132 (Netherlands); Cate, Olle Th.J. ten, E-mail: T.J.tenCate@umcutrecht.nl [Center for Research and Development of Education at University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht (Netherlands); Gijp, Anouk van der, E-mail: A.vanderGijp-2@umcutrecht.nl [Radiology Department at University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht, Room E01.132 (Netherlands); Mol, Christian P., E-mail: C.Mol@umcutrecht.nl [Image Sciences Institute at University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht (Netherlands); Vincken, Koen L., E-mail: K.Vincken@umcutrecht.nl [Image Sciences Institute at University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht (Netherlands)

    2015-05-15

    Rationale and objectives: Current radiology practice increasingly involves interpretation of volumetric data sets. In contrast, most radiology tests still contain only 2D images. We introduced a new testing tool that allows for stack viewing of volumetric images in our undergraduate radiology program. We hypothesized that tests with volumetric CT-images enhance test quality, in comparison with traditional completely 2D image-based tests, because they might better reflect required skills for clinical practice. Materials and methods: Two groups of medical students (n = 139; n = 143), trained with 2D and volumetric CT-images, took a digital radiology test in two versions (A and B), each containing both 2D and volumetric CT-image questions. In a questionnaire, they were asked to comment on the representativeness for clinical practice, difficulty and user-friendliness of the test questions and testing program. Students’ test scores and reliabilities, measured with Cronbach's alpha, of 2D and volumetric CT-image tests were compared. Results: Estimated reliabilities (Cronbach's alphas) were higher for volumetric CT-image scores (version A: .51 and version B: .54), than for 2D CT-image scores (version A: .24 and version B: .37). Participants found volumetric CT-image tests more representative of clinical practice, and considered them to be less difficult than volumetric CT-image questions. However, in one version (A), volumetric CT-image scores (M 80.9, SD 14.8) were significantly lower than 2D CT-image scores (M 88.4, SD 10.4) (p < .001). The volumetric CT-image testing program was considered user-friendly. Conclusion: This study shows that volumetric image questions can be successfully integrated in students’ radiology testing. Results suggests that the inclusion of volumetric CT-images might improve the quality of radiology tests by positively impacting perceived representativeness for clinical practice and increasing reliability of the test.

  1. Scatter correction, intermediate view estimation and dose characterization in megavoltage cone-beam CT imaging

    Science.gov (United States)

    Sramek, Benjamin Koerner

    The ability to deliver conformal dose distributions in radiation therapy through intensity modulation and the potential for tumor dose escalation to improve treatment outcome has necessitated an increase in localization accuracy of inter- and intra-fractional patient geometry. Megavoltage cone-beam CT imaging using the treatment beam and onboard electronic portal imaging device is one option currently being studied for implementation in image-guided radiation therapy. However, routine clinical use is predicated upon continued improvements in image quality and patient dose delivered during acquisition. The formal statement of hypothesis for this investigation was that the conformity of planned to delivered dose distributions in image-guided radiation therapy could be further enhanced through the application of kilovoltage scatter correction and intermediate view estimation techniques to megavoltage cone-beam CT imaging, and that normalized dose measurements could be acquired and inter-compared between multiple imaging geometries. The specific aims of this investigation were to: (1) incorporate the Feldkamp, Davis and Kress filtered backprojection algorithm into a program to reconstruct a voxelized linear attenuation coefficient dataset from a set of acquired megavoltage cone-beam CT projections, (2) characterize the effects on megavoltage cone-beam CT image quality resulting from the application of Intermediate View Interpolation and Intermediate View Reprojection techniques to limited-projection datasets, (3) incorporate the Scatter and Primary Estimation from Collimator Shadows (SPECS) algorithm into megavoltage cone-beam CT image reconstruction and determine the set of SPECS parameters which maximize image quality and quantitative accuracy, and (4) evaluate the normalized axial dose distributions received during megavoltage cone-beam CT image acquisition using radiochromic film and thermoluminescent dosimeter measurements in anthropomorphic pelvic and head and

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    , especially when transferring data across the (network-) borders of different hospitals. Overall, the most important precondition for successful integration of functional imaging in RT treatment planning is the goal orientated as well as close and thorough communication between nuclear medicine......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...

  3. 'Ready-access' CT imaging for an orthopaedic trauma clinic.

    LENUS (Irish Health Repository)

    Cawley, D

    2011-03-01

    \\'Ready-Access\\' to CT imaging facilities in Orthopaedic Trauma Clinics is not a standard facility. This facility has been available at the regional trauma unit, in Merlin Park Hospital, Galway for the past four years. We reviewed the use of this facility over a 2-year period when 100 patients had CT scans as part of their trauma clinic assessment. The rate of CT scan per clinic was 0.6. The mean waiting time for a CT scan was 30 minutes. 20 (20%) new fractures were confirmed, 33 (33%) fractures were out-ruled, 25 (25%) fractures demonstrated additional information and 8 (8%) had additional fractures. 20 (20%) patients were discharged and 12 (12%) patients were admitted as a result of the CT scan. It adds little time and cost to CT scanning lists.

  4. Recurrent Convolutional Networks for Pulmonary Nodule Detection in CT Imaging

    OpenAIRE

    Ypsilantis, Petros-Pavlos; Montana, Giovanni

    2016-01-01

    Computed tomography (CT) generates a stack of cross-sectional images covering a region of the body. The visual assessment of these images for the identification of potential abnormalities is a challenging and time consuming task due to the large amount of information that needs to be processed. In this article we propose a deep artificial neural network architecture, ReCTnet, for the fully-automated detection of pulmonary nodules in CT scans. The architecture learns to distinguish nodules and...

  5. A new method for robust organ positioning in CT images

    NARCIS (Netherlands)

    Vik, T.; Bystrov, D.; Schadewaldt, N.; Schulz, H.; Peters, J.

    2012-01-01

    A robust initialization is the key to any successful segmentation process in medical images. For CT images, initialization ischallenging because the quality, appearance, content and field-of-view of the images are highly variable, and, furthermore, the user tolerance to errors in clinical applicatio

  6. A CT Image Segmentation Algorithm Based on Level Set Method

    Institute of Scientific and Technical Information of China (English)

    QU Jing-yi; SHI Hao-shan

    2006-01-01

    Level Set methods are robust and efficient numerical tools for resolving curve evolution in image segmentation. This paper proposes a new image segmentation algorithm based on Mumford-Shah module. The method is used to CT images and the experiment results demonstrate its efficiency and veracity.

  7. Castleman disease of the neck: CT and MR imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xin-hua [Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060 (China); Song, Hao-ming [Department of Cardiology, Shanghai Tongji Hospital, Shanghai 200065 (China); Liu, Qing-yu [Department of Radiology, The Second Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120 (China); Cao, Yun [Department of Pathology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060 (China); Li, Guo-hong [Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060 (China); Zhang, Wei-dong, E-mail: dongw.z@163.com [Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060 (China)

    2014-11-15

    Objective: To characterize the computed tomography (CT) and magnetic resonance imaging (MRI) findings of Castleman disease of the neck. Methods: The imaging findings of 21 patients with Castleman disease of the neck were reviewed retrospectively. Of the 21 patients, 16 underwent unenhanced and contrast-enhanced CT scans; 5 underwent unenhanced and contrast-enhanced MRI scans. Results: The unenhanced CT images showed isolated or multiple well-defined homogenous mild hypodensity lesions in fifteen cases, and a heterogeneous nodule with central areas of mild hypodensity in one case. Calcification was not observed in any of the patients. In five patients, MR T1-weighted images revealed well-defined, homogeneous isointense or mild hyperintense lesions to the muscle; T2-weighted images showed these as intermediate hyperintense. Sixteen cases showed intermediate to marked homogeneous enhancement on contrast-enhanced CT or MR T1-weighted images. Of the other five cases that underwent double-phase CT scans, four showed mild or intermediate heterogeneous enhancement at the arterial phase, and homogeneous intermediate or marked enhancement at the venous phase; the remaining case showed mild and intermediate ring-enhancement with a central non-enhanced area at the arterial and venous phases, respectively. Conclusion: Castleman disease of the neck can be characterized as solitary or multiple well-defined, mild hypodensity or homogeneous intense lesions on plain CT/MR scans, and demonstrates intermediate and marked enhancement on contrast-enhanced CT/MR scans. On double-phase CT scans, Castleman disease often demonstrates mild enhancement at the arterial phase, and gradually uniform enhancement at venous phase. Double-phase enhanced CT or MRI may help to differentiate Castleman disease from other diseases.

  8. Image quality assessment for CT used on small animals

    Energy Technology Data Exchange (ETDEWEB)

    Cisneros, Isabela Paredes, E-mail: iparedesc@unal.edu.co; Agulles-Pedrós, Luis, E-mail: lagullesp@unal.edu.co [Universidad Nacional de Colombia, Departamento de Física, Grupo de Física Médica (Colombia)

    2016-07-07

    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. Image quality assessment for CT used on small animals

    Science.gov (United States)

    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.

  10. A Novel Mouse Segmentation Method Based on Dynamic Contrast Enhanced Micro-CT Images

    Science.gov (United States)

    Yan, Dongmei; Zhang, Zhihong; Luo, Qingming; Yang, Xiaoquan

    2017-01-01

    With the development of hybrid imaging scanners, micro-CT is widely used in locating abnormalities, studying drug metabolism, and providing structural priors to aid image reconstruction in functional imaging. Due to the low contrast of soft tissues, segmentation of soft tissue organs from mouse micro-CT images is a challenging problem. In this paper, we propose a mouse segmentation scheme based on dynamic contrast enhanced micro-CT images. With a homemade fast scanning micro-CT scanner, dynamic contrast enhanced images were acquired before and after injection of non-ionic iodinated contrast agents (iohexol). Then the feature vector of each voxel was extracted from the signal intensities at different time points. Based on these features, the heart, liver, spleen, lung, and kidney could be classified into different categories and extracted from separate categories by morphological processing. The bone structure was segmented using a thresholding method. Our method was validated on seven BALB/c mice using two different classifiers: a support vector machine classifier with a radial basis function kernel and a random forest classifier. The results were compared to manual segmentation, and the performance was assessed using the Dice similarity coefficient, false positive ratio, and false negative ratio. The results showed high accuracy with the Dice similarity coefficient ranging from 0.709 ± 0.078 for the spleen to 0.929 ± 0.006 for the kidney. PMID:28060917

  11. Three-dimensional multislice CT imaging of otitis media

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Miyako [Yanagibasi Hospital, Tokyo (Japan); Yoshikawa, Hiroshi; Hosokawa, Akira; Furukawa, Tomoyasu; Ichikawa, Ginichiro [Juntendo Univ., Tokyo (Japan). School of Medicine; Wada, Akihiro; Ando, Ichiro [Juntendo Univ., Chiba (Japan). Urayasu Hospital

    2002-07-01

    In recent years, the multislice CT system has come into practical use that enables table movement of half mm, resulting in a significant improvement in resolution. The use of this CT system enables to depict the entire auditory ossicles, including the stapes. 3D reconstruction was performed using helical CT data in 5 patients with chronic otitis media and 5 patients with cholesteatoma. An Aquilion Multi (Toshiba) multislice helical CT scanner and a Xtension (Toshiba) image workstation were used in this study. We demonstrated the 3D display with axial, coronal and sagittal images. Compared with the normal ears, it was necessary to set a higher threshold for the affected ears. It is important to select suitable threshold for demonstration of 3D images optimally. Bone destruction of the stapes was confirmed at surgery in 2 ears. The stapes was observed at 3D-CT imaging in other 18 ears. It was found that the 3D images of the ossicular destruction in ears with cholesteatoma were consistent with surgical findings. It is therefore concluded that 3D imaging of the middle ear using a multislice CT scanner is clinically useful. (author)

  12. CT versus MR in neonatal brain imaging at term

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Richard L.; Robson, Caroline D.; Zurakowski, David; Antiles, Sharon; Strauss, Keith; Mulkern, Robert V. [Department of Radiology, Children' s Hospital Medical Center, Harvard Medical School, 300 Longwood Avenue, MA 02115, Boston (United States)

    2003-07-01

    Recent reports have highlighted the lifetime risk of malignancy from using ionizing radiation in pediatric imaging. Computed tomography (CT), which uses ionizing radiation, is employed extensively for neonatal brain imaging of term infants. Magnetic resonance (MR) provides an alternative that does not use ionizing radiation. The purpose of this study was to assess the cross-modality agreement and interobserver agreement of CT and MR brain imaging of the term or near-term neonate. Brain CT and MR images of 48 neonates were retrospectively reviewed by two pediatric neuroradiologists. CT and MR examinations had been obtained within 72 h of one another in all patients. CT was obtained with 5 mm collimation (KV=120, mAs=340). MR consisted of T1-weighted imaging (TR/TE=300/14; 4-mm slice thickness/1-mm gap), T2-weighted imaging (TR/TE/etl= 3000/126/16; 4-mm slice thickness/1-mm gap), and line scan diffusion imaging (LSDI) (TR/TE/b factor=1258/63/750; nominal 4-mm slice thickness/3-mm gap). The brain was categorized as normal or abnormal on both CT and MR. Ischemic injury was the most common brain abnormality demonstrated. McNemar's test indicated no significant difference between CT and MR test results for reader 1 (P=0.22) or reader 2 (P=0.45). The readers agreed on the presence or absence of abnormality on CT in 40 patients (83.3%) and on MR in 45 patients (93.8%). For CT, the kappa coefficient indicated excellent interobserver agreement ({kappa}=0.68), although the lower limit of the 95% confidence interval extends to {kappa}=0.55, which indicates only good-to-moderate agreement. For MR, the kappa coefficient indicated almost perfect interobserver agreement ({kappa}=0.88) with the 95% confidence interval extending to a lower limit of {kappa}=0.76, which represents excellent agreement. Because MR demonstrates findings similar to CT and has greater interobserver agreement, it appears that MR is a superior test to CT in determining brain abnormalities in the term

  13. Four-Dimensional Computerized Tomography (4D-CT) Reconstruction Based on the Similarity Measure of Spatial Adjacent Images

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shu-xu; ZHOU Ling-hong; CHEN Guang-jie; LIN Sheng-qu; YE Yu-sheng; ZHANG Hai-nan

    2008-01-01

    Objective:To investigate the feasibility of a 4D-CT reconstruction method based on the similarity principle of spatial adjacent images and mutual information measure. Methods:A motor driven sinusoidal motion platform made in house was used to create one-dimensional periodical motion that was along the longitudinal axis of the CT couch. The amplitude of sinusoidal motion was set to an amplitude of ±1 cm. The period of the motion was adjustable and set to 3.5 s. Phantom objects of two eggs were placed in a Styrofoam block, which in turn were placed on the motion platform. These objects were used to simulate volumes of interest undergoing ideal periodic motion. CT data of static phantom were acquired using a multi-slice general electric (GE) LightSpeed 16-slice CT scanner in an axial mode. And the CT data of periodical motion phantom were acquired in an axial and cine-mode scan. A software program was developed by using VC++ and VTK software tools to resort the CT data and reconstruct the 4D-CT. Then all of the CT data with same phase were sorted by the program into the same series based on the similarity principle of spatial adjacent images and mutual information measure among them, and 3D reconstruction of different phase CT data were completed by using the software. Results:All of the CT data were sorted accurately into different series based on the similarity principle of spatial adjacent images and mutual information measures among them. Compared with the unsorted CT data, the motion artifacts in the 3D reconstruction of sorted CT data were reduced significantly, and all of the sorted CT series result in a 4D-CT that reflected the characteristic of the periodical motion phantom. Conclusion:Time-resolved 4D-CT reconstruction can be implemented with any general multi-slice CT scanners based on the similarity principle of spatial adjacent images and mutual information measure.The process of the 4D-CT data acquisition and reconstruction were not restricted to the

  14. An FBP image reconstruction algorithm for x-ray differential phase contrast CT

    Science.gov (United States)

    Qi, Zhihua; Chen, Guang-Hong

    2008-03-01

    Most recently, a novel data acquisition method has been proposed and experimentally implemented for x-ray differential phase contrast computed tomography (DPC-CT), in which a conventional x-ray tube and a Talbot-Lau type interferometer were utilized in data acquisition. The divergent nature of the data acquisition system requires a divergent-beam image reconstruction algorithm for DPC-CT. This paper focuses on addressing this image reconstruction issue. We developed a filtered backprojection algorithm to directly reconstruct the DPC-CT images from acquired projection data. The developed algorithm allows one to directly reconstruct the decrement of the real part of the refractive index from the measured data. In order to accurately reconstruct an image, the data need to be acquired over an angular range of at least 180° plus the fan-angle. Different from the parallel beam data acquisition and reconstruction methods, a 180° rotation angle for data acquisition system does not provide sufficient data for an accurate reconstruction of the entire field of view. Numerical simulations have been conducted to validate the image reconstruction algorithm.

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

    Directory of Open Access Journals (Sweden)

    Sara Gargiulo

    2012-01-01

    Full Text Available 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.

  16. Self-acquired patient images: the promises and the pitfalls.

    Science.gov (United States)

    Damanpour, Shadi; Srivastava, Divya; Nijhawan, Rajiv I

    2016-03-01

    Self-acquired patient images, also known as selfies, are increasingly utilized in the practice of dermatology; however, research on their utility is somewhat limited. While the implementation of selfies has yet to be universally accepted, their role in triage appears to be especially useful. The potential for reducing office wait times, expediting referrals, and providing dermatologic services to patients with limited access to care is promising. In addition, as technology advances, the number of smartphone applications related to dermatology that are available to the general public has risen exponentially. With appropriate standardization, regulation, and confidentiality measures, these tools can be feasible adjuncts in clinical practice, dermatologic surgery, and teledermatology. Selfies likely will have a large role in dermatologic practice and delivery in the future.

  17. CT of the congenital and spleen acquired abnormalities; TC de las anomalias congenitas y adquiridas del bazo

    Energy Technology Data Exchange (ETDEWEB)

    Gil, A.; Ibarburen, C.; Anton, E.; Temprano, C.; Salgado, F. M.; Davila, J. [Hospital de Mostoles. Madrid (Spain)

    2000-07-01

    This study aims to review the X-ray characteristics of the different entities that can affect the spleen by illustrating the semiology that is seen in the Computed tomography (CT). We review 239 cases of splenic pathology that occurred during a period of 15 years (1985-1999). All of the patients underwent a CT with and without i. v. contrast. Most of the patients were submitted to a splenectomy and histological correlation was performed. The CT is the imaging technique of choice in the diagnosis of splenic diseases since the ultrasonography, although a very sensitive technique, is very inspecific. (Author) 36 refs.

  18. Imaging of female pelvic malignancies regarding MRI, CT, and PET/CT. Pt. 2

    Energy Technology Data Exchange (ETDEWEB)

    Alt, Celine D.; Kauczor, Hans-Ulrich; Hallscheidt, Peter [Heidelberg Univ. (Germany). Dept. of Diagnostic and Interventional Radiology; Brocker, Kerstin A.; Eichbaum, Michael; Sohn, Christof; Arnegger, Florian U. [Heidelberg Univ. (Germany). Dept. of Obstetrics and Gynecology

    2011-11-15

    To compose diagnostic standard operating procedures for both clinical and imaging assessment for vulvar and vaginal cancer, for vaginal sarcoma, and for ovarian cancer. The literature was reviewed for diagnosing the above mentioned malignancies in the female pelvis. Special focus herein lies in tumor representation in MRI, followed by the evaluation of CT and PET/CT for this topic. MRI is a useful additional diagnostic complement but by no means replaces established methods of gynecologic diagnostics and ultrasound. In fact, MRI is only implemented in the guidelines for vulvar cancer. According to the current literature, CT is still the cross-sectional imaging modality of choice for evaluating ovarian cancer. PET/CT appears to have advantages for staging and follow-up in sarcomas and cancers of the ovaries. (orig.)

  19. Efficient 3D rigid-body registration of micro-MR and micro-CT trabecular bone images

    Science.gov (United States)

    Rajapakse, C. S.; Magland, J.; Wehrli, S. L.; Zhang, X. H.; Liu, X. S.; Guo, X. E.; Wehrli, F. W.

    2008-03-01

    Registration of 3D images acquired from different imaging modalities such as micro-magnetic resonance imaging (µMRI) and micro-computed tomography (µCT) are of interest in a number of medical imaging applications. Most general-purpose multimodality registration algorithms tend to be computationally intensive and do not take advantage of the shape of the imaging volume. Multimodality trabecular bone (TB) images of cylindrical cores, for example, tend to be misaligned along and around the axial direction more than that around other directions. Additionally, TB images acquired by µMRI can differ substantially from those acquired by µCT due to apparent trabecular thickening from magnetic susceptibility boundary effects and non-linear intensity correspondence. However, they share very similar contrast characteristics since the images essentially represent a binary tomographic system. The directional misalignment and the fundamental similarities of the two types of images can be exploited to achieve fast 3D registration. Here we present an intensity cross-correlation based 3D registration algorithm for registering 3D specimen images from cylindrical cores of cadaveric TB acquired by µMRI and µCT in the context of finite-element modeling to assess the bone's mechanical constants. The algorithm achieves the desired registration by first coarsely approximating the three translational and three rotational parameters required to align the µMR images to the µCT scan coordinate frame and fine-tuning the parameters in the neighborhood of the approximate solution. The algorithm described here is suitable for 3D rigid-body image registration applications where through-plane rotations are known to be relatively small. The accuracy of the technique is constrained by the image resolution and in-plane angular increments used.

  20. Dosimetric impact of image artifact from a wide-bore CT scanner in radiotherapy treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Vincent; Podgorsak, Matthew B.; Tran, Tuan-Anh; Malhotra, Harish K.; Wang, Iris Z. [Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 and Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 and Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14214 (United States)

    2011-07-15

    Purpose: Traditional computed tomography (CT) units provide a maximum scan field-of-view (sFOV) diameter of 50 cm and a limited bore size, which cannot accommodate a large patient habitus or an extended simulation setup in radiation therapy (RT). Wide-bore CT scanners with increased bore size were developed to address these needs. Some scanners have the capacity to reconstruct the CT images at an extended FOV (eFOV), through data interpolation or extrapolation, using projection data acquired with a conventional sFOV. Objects that extend past the sFOV for eFOV reconstruction may generate image artifacts resulting from truncated projection data; this may distort CT numbers and structure contours in the region beyond the sFOV. The purpose of this study was to evaluate the dosimetric impact of image artifacts from eFOV reconstruction with a wide-bore CT scanner in radiotherapy (RT) treatment planning. Methods: Testing phantoms (i.e., a mini CT phantom with equivalent tissue inserts, a set of CT normal phantoms and anthropomorphic phantoms of the thorax and the pelvis) were used to evaluate eFOV artifacts. Reference baseline images of these phantoms were acquired with the phantom centrally positioned within the sFOV. For comparison, the phantoms were then shifted laterally and scanned partially outside the sFOV, but still within the eFOV. Treatment plans were generated for the thoracic and pelvic anthropomorphic phantoms utilizing the Eclipse treatment planning system (TPS) to study the potential effects of eFOV artifacts on dose calculations. All dose calculations of baseline and test treatment plans were carried out using the same MU. Results: Results show that both body contour and CT numbers are altered by image artifacts in eFOV reconstruction. CT number distortions of up to -356 HU for bone tissue and up to 323 HU for lung tissue were observed in the mini CT phantom. Results from the large body normal phantom, which is close to a clinical patient size, show

  1. Chest CT using spectral filtration: radiation dose, image quality, and spectrum of clinical utility

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Franziska M.; Johnson, Thorsten R.C.; Sommer, Wieland H.; Thierfelder, Kolja M.; Meinel, Felix G. [University Hospital Munich, Institute for Clinical Radiology, Munich (Germany)

    2015-06-01

    To determine the radiation dose, image quality, and clinical utility of non-enhanced chest CT with spectral filtration. We retrospectively analysed 25 non-contrast chest CT examinations acquired with spectral filtration (tin-filtered Sn100 kVp spectrum) compared to 25 examinations acquired without spectral filtration (120 kV). Radiation metrics were compared. Image noise was measured. Contrast-to-noise-ratio (CNR) and figure-of-merit (FOM) were calculated. Diagnostic confidence for the assessment of various thoracic pathologies was rated by two independent readers. Effective chest diameters were comparable between groups (P = 0.613). In spectral filtration CT, median CTDI{sub vol}, DLP, and size-specific dose estimate (SSDE) were reduced (0.46 vs. 4.3 mGy, 16 vs. 141 mGy*cm, and 0.65 vs. 5.9 mGy, all P < 0.001). Spectral filtration CT had higher image noise (21.3 vs. 13.2 HU, P < 0.001) and lower CNR (47.2 vs. 75.3, P < 0.001), but was more dose-efficient (FOM 10,659 vs. 2,231/mSv, P < 0.001). Diagnostic confidence for parenchymal lung disease and osseous pathologies was lower with spectral filtration CT, but no significant difference was found for pleural pathologies, pulmonary nodules, or pneumonia. Non-contrast chest CT using spectral filtration appears to be sufficient for the assessment of a considerable spectrum of thoracic pathologies, while providing superior dose efficiency, allowing for substantial radiation dose reduction. (orig.)

  2. Relaxed Linearized Algorithms for Faster X-Ray CT Image Reconstruction.

    Science.gov (United States)

    Nien, Hung; Fessler, Jeffrey A

    2016-04-01

    Statistical image reconstruction (SIR) methods are studied extensively for X-ray computed tomography (CT) due to the potential of acquiring CT scans with reduced X-ray dose while maintaining image quality. However, the longer reconstruction time of SIR methods hinders their use in X-ray CT in practice. To accelerate statistical methods, many optimization techniques have been investigated. Over-relaxation is a common technique to speed up convergence of iterative algorithms. For instance, using a relaxation parameter that is close to two in alternating direction method of multipliers (ADMM) has been shown to speed up convergence significantly. This paper proposes a relaxed linearized augmented Lagrangian (AL) method that shows theoretical faster convergence rate with over-relaxation and applies the proposed relaxed linearized AL method to X-ray CT image reconstruction problems. Experimental results with both simulated and real CT scan data show that the proposed relaxed algorithm (with ordered-subsets [OS] acceleration) is about twice as fast as the existing unrelaxed fast algorithms, with negligible computation and memory overhead.

  3. An image-guided tool to prevent hospital acquired infections

    Science.gov (United States)

    Nagy, Melinda; Szilágyi, László; Lehotsky, Ákos; Haidegger, Tamás; Benyó, Balázs

    2011-03-01

    Hospital Acquired Infections (HAI) represent the fourth leading cause of death in the United States, and claims hundreds of thousands of lives annually in the rest of the world. This paper presents a novel low-cost mobile device|called Stery-Hand|that helps to avoid HAI by improving hand hygiene control through providing an objective evaluation of the quality of hand washing. The use of the system is intuitive: having performed hand washing with a soap mixed with UV re ective powder, the skin appears brighter in UV illumination on the disinfected surfaces. Washed hands are inserted into the Stery-Hand box, where a digital image is taken under UV lighting. Automated image processing algorithms are employed in three steps to evaluate the quality of hand washing. First, the contour of the hand is extracted in order to distinguish the hand from the background. Next, a semi-supervised clustering algorithm classies the pixels of the hand into three groups, corresponding to clean, partially clean and dirty areas. The clustering algorithm is derived from the histogram-based quick fuzzy c-means approach, using a priori information extracted from reference images, evaluated by experts. Finally, the identied areas are adjusted to suppress shading eects, and quantied in order to give a verdict on hand disinfection quality. The proposed methodology was validated through tests using hundreds of images recorded in our laboratory. The proposed system was found robust and accurate, producing correct estimation for over 98% of the test cases. Stery-Hand may be employed in general practice, and it may also serve educational purposes.

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

    Science.gov (United States)

    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.

  5. PET/CT imaging and radioimmunotherapy of prostate cancer

    OpenAIRE

    Bouchelouche, Kirsten; Tagawa, Scott T.; Goldsmith, Stanley J.; Turkbey, Baris; Capala, Jacek; Choyke, Peter

    2011-01-01

    Prostate cancer is a common cancer in men and continues to be a major health problem. Imaging plays an important role in the clinical management of patients with prostate cancer. An important goal for prostate cancer imaging is more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information. Positron emission tomography (PET)/computed tomography (CT) in oncology is emerging as an important imaging tool. The most common radiotracer for PE...

  6. TU-A-12A-02: Novel Lung Ventilation Imaging with Single Energy CT After Single Inhalation of Xenon: Comparison with SPECT Ventilation Images

    Energy Technology Data Exchange (ETDEWEB)

    Negahdar, M [Stanford University School of Medicine, Stanford, CA (United States); Yamamoto, T [UC Davis School of Medicine, Sacramento, CA (United States); Shultz, D; Gable, L; Shan, X; Mittra, E; Loo, B; Maxim, P [Stanford University, Stanford, CA (United States); Diehn, M [Stanford University, Palo Alto, CA (United States)

    2014-06-15

    Purpose: We propose a novel lung functional imaging method to determine the spatial distribution of xenon (Xe) gas in a single inhalation as a measure of regional ventilation. We compare Xe-CT ventilation to single-photon emission CT (SPECT) ventilation, which is the current clinical reference. Regional lung ventilation information may be useful for the diagnosis and monitoring of pulmonary diseases such as COPD, radiotherapy planning, and assessing the progression of toxicity after radiation therapy. Methods: In an IRB-approved clinical study, Xe-CT and SPECT ventilation scans were acquired for three patients including one patient with severe emphysema and two lung cancer patients treated with radiotherapy. For Xe- CT, we acquired two breath-hold single energy CT images of the entire lung with inspiration of 100% O2 and a mixture of 70% Xe and 30% O2, respectively. A video biofeedback system was used to achieve reproducible breath-holds. We used deformable image registration to align the breathhold images with each other to accurately subtract them, producing a map of the distribution of Xe as a surrogate of lung ventilation. We divided each lung into twelve parts and correlated the Hounsfield unit (HU) enhancement at each part with the SPECT ventilation count of the corresponding part of the lung. Results: The mean of the Pearson linear correlation coefficient values between the Xe-CT and ventilation SPECT count for all three patients were 0.62 (p<0.01). The Xe-CT image had a higher resolution than SPECT, and did not show central airway deposition artifacts that were present in the SPECT image. Conclusion: We developed a rapid, safe, clinically practical, and potentially widely accessible method for regional lung functional imaging. We demonstrated strong correlations between the Xe-CT ventilation image and SPECT ventilation image as the clinical reference. This ongoing study will investigate more patients to confirm this finding.

  7. US, CT and MR imaging characteristics of nephroblastomatosis

    Energy Technology Data Exchange (ETDEWEB)

    Rohrschneider, W.K.; Weirich, A.; Darge, K.; Troeger, J. [Department of Pediatric Radiology, University of Heidelberg, Im Neuenheimer Feld 153, D-69 120 Heidelberg (Germany); Rieden, K. [Department of Radiology, University of Heidelberg, Heidelberg (Germany); Graf, N. [Department of Paediatric Oncology, Children`s Hospital, University of Homburg/Saar (Germany)

    1998-06-01

    Objectives. To describe the imaging features of nephroblastomatosis with US, CT and MR, to point out characteristics of differentiation between nephrogenic rests (NR) and Wilms` tumour (WT) and to determine the most appropriate imaging modality. Materials and methods. We reviewed the US, CT and MR images of 29 cases of histopathologically confirmed nephroblastomatosis sent to our department for reference evaluation (German nephroblastoma study). The series included 17 kidneys with NR, 6 kidneys with WT and 32 kidneys with both NR and WT. Results. NR presented as multinodular, peripheral, cortical lesions, the diffuse form of distribution being less common. Foci were homogeneous and of low echogenicity, density or signal intensity. The lesions were most clearly depicted with contrast-enhanced CT and T1-weighted (T1-W) MR images. Lesions smaller than 1 cm were rarely identified by US. The most reliable criterion to differentiate NR from WT was their homogeneity. Conclusions. Contrast-enhanced CT and T1-W MR images are of similar potential and superior to US in the diagnosis of nephroblastomatosis. Due to the significant radiation dose of serial CT, MR imaging should be the method of choice wherever it is available. The cost-effectiveness and availability of US makes it ideal for serial follow-up of known lesions. (orig.) With 8 figs., 1 tab., 23 refs.

  8. Molecular imaging agents for SPECT (and SPECT/CT)

    Energy Technology Data Exchange (ETDEWEB)

    Gnanasegaran, Gopinath [Guy' s and St Thomas' NHS Foundation Trust, Department of Nuclear Medicine, London (United Kingdom); Ballinger, James R. [Guy' s and St Thomas' NHS Foundation Trust, Department of Nuclear Medicine, London (United Kingdom); King' s College London, Division of Imaging Sciences and Biomedical Engineering, London (United Kingdom)

    2014-05-15

    The development of hybrid single photon emission computed tomography/computed tomography (SPECT/CT) cameras has increased the diagnostic value of many existing single photon radiopharmaceuticals. Precise anatomical localization of lesions greatly increases diagnostic confidence in bone imaging of the extremities, infection imaging, sentinel lymph node localization, and imaging in other areas. Accurate anatomical localization is particularly important prior to surgery, especially involving the parathyroid glands and sentinel lymph node procedures. SPECT/CT plays a role in characterization of lesions, particularly in bone scintigraphy and radioiodine imaging of metastatic thyroid cancer. In the development of novel tracers, SPECT/CT is particularly important in monitoring response to therapies that do not result in an early change in lesion size. Preclinical SPECT/CT devices, which actually have spatial resolution superior to PET/CT devices, have become essential in characterization of the biodistribution and tissue kinetics of novel tracers, allowing coregistration of serial studies within the same animals, which serves both to reduce biological variability and reduce the number of animals required. In conclusion, SPECT/CT increases the utility of existing radiopharmaceuticals and plays a pivotal role in the evaluation of novel tracers. (orig.)

  9. A registration-based segmentation method with application to adiposity analysis of mice microCT images

    Science.gov (United States)

    Bai, Bing; Joshi, Anand; Brandhorst, Sebastian; Longo, Valter D.; Conti, Peter S.; Leahy, Richard M.

    2014-04-01

    Obesity is a global health problem, particularly in the U.S. where one third of adults are obese. A reliable and accurate method of quantifying obesity is necessary. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) are two measures of obesity that reflect different associated health risks, but accurate measurements in humans or rodent models are difficult. In this paper we present an automatic, registration-based segmentation method for mouse adiposity studies using microCT images. We co-register the subject CT image and a mouse CT atlas. Our method is based on surface matching of the microCT image and an atlas. Surface-based elastic volume warping is used to match the internal anatomy. We acquired a whole body scan of a C57BL6/J mouse injected with contrast agent using microCT and created a whole body mouse atlas by manually delineate the boundaries of the mouse and major organs. For method verification we scanned a C57BL6/J mouse from the base of the skull to the distal tibia. We registered the obtained mouse CT image to our atlas. Preliminary results show that we can warp the atlas image to match the posture and shape of the subject CT image, which has significant differences from the atlas. We plan to use this software tool in longitudinal obesity studies using mouse models.

  10. CT and MR imaging after middle ear surgery

    Energy Technology Data Exchange (ETDEWEB)

    Koesling, Sabrina E-mail: sabrina.koesling@medizin.uni-halle.de; 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.

  11. CT imaging in acute ischemic stroke

    NARCIS (Netherlands)

    Borst, J.

    2016-01-01

    Time is of the essence when treating acute ischemic stroke, to limit the damage caused. One form of intra-arterial treatment (IAT) used in such cases is the mechanical removal of the blood clot using stent-retrievers. It is thought that patient selection for IAT requires improvement and that CT

  12. CT guided diffuse optical tomography for breast cancer imaging

    Science.gov (United States)

    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.

  13. CT imaging with a mobile C-arm prototype

    Science.gov (United States)

    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.

  14. Variability of Image Features Computed from Conventional and Respiratory-Gated PET/CT Images of Lung Cancer

    Directory of Open Access Journals (Sweden)

    Jasmine A. Oliver

    2015-12-01

    Full Text Available Radiomics is being explored for potential applications in radiation therapy. How various imaging protocols affect quantitative image features is currently a highly active area of research. To assess the variability of image features derived from conventional [three-dimensional (3D] and respiratory-gated (RG positron emission tomography (PET/computed tomography (CT images of lung cancer patients, image features were computed from 23 lung cancer patients. Both protocols for each patient were acquired during the same imaging session. PET tumor volumes were segmented using an adaptive technique which accounted for background. CT tumor volumes were delineated with a commercial segmentation tool. Using RG PET images, the tumor center of mass motion, length, and rotation were calculated. Fifty-six image features were extracted from all images consisting of shape descriptors, first-order features, and second-order texture features. Overall, 26.6% and 26.2% of total features demonstrated less than 5% difference between 3D and RG protocols for CT and PET, respectively. Between 10 RG phases in PET, 53.4% of features demonstrated percent differences less than 5%. The features with least variability for PET were sphericity, spherical disproportion, entropy (first and second order, sum entropy, information measure of correlation 2, Short Run Emphasis (SRE, Long Run Emphasis (LRE, and Run Percentage (RPC; and those for CT were minimum intensity, mean intensity, Root Mean Square (RMS, Short Run Emphasis (SRE, and RPC. Quantitative analysis using a 3D acquisition versus RG acquisition (to reduce the effects of motion provided notably different image feature values. This study suggests that the variability between 3D and RG features is mainly due to the impact of respiratory motion.

  15. CT perfusion imaging in the management of posterior reversible encephalopathy

    Energy Technology Data Exchange (ETDEWEB)

    Casey, S.O.; McKinney, A.; Teksam, M.; Liu, H.; Truwit, C.L. [Department of Radiology, University of Minnesota Medical School, 420 Delaware Street SE, Box 292, MN 55455, Minneapolis (United States)

    2004-04-01

    A 13-year-old girl with a renal transplant presented with hypertension and seizures. CT and MRI demonstrated typical bilateral parietal, occipital and posterior frontal cortical and subcortical edema, thought to represent posterior reversible encephalopathy syndrome. The cause was presumed to be hypertension. Antihypertensive therapy was started, lowering of the blood pressure in the range of 110-120 mmHg systolic. However, stable xenon (Xe) CT perfusion imaging revealed ischemia within the left parietal occipital region. The antihypertensive was adjusted which increased both the systolic and diastolic blood pressure by 31 mm Hg. The patient was re-imaged with Xe CT and was found to have resolution of the ischemic changes within the left parietal occipital region. In this report, we present a case in which stable Xe CT was used to monitor the degree of cerebral perfusion and guide titration of antihypertensive therapy. Such brain perfusion monitoring may have helped to prevent infarction of our patient. (orig.)

  16. CT imaging of mass-like renal lesions in children

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Edward Y. [Children' s Hospital Boston, Harvard Medical School, Department of Radiology, Boston, MA (United States)

    2007-09-15

    Mass-like renal lesions in children occur in a diverse spectrum of conditions including benign and malignant neoplasm, infection, infarction, lymphatic malformation, and traumatic injury. Although mass-like renal lesions can sometimes be suspected on plain radiographs and evaluated with US in children, subsequent CT is usually performed for the confirmation of diagnosis and further characterization. The purpose of this pictorial essay was to review the CT imaging findings of both common and uncommon mass-like renal lesions in pediatric patients. Understanding the characteristic CT appearance of mass-like renal lesions in children enables an accurate diagnosis and optimizes patient management. (orig.)

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

    OpenAIRE

    2015-01-01

    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 o...

  18. Pediatric renal leukemia: spectrum of CT imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Hilmes, Melissa A. [University of Michigan Health System, C.S. Mott Children' s Hospital, Section of Pediatric Radiology, Ann Arbor, MI (United States); Vanderbilt University Children' s Hospital, Section of Pediatric Radiology, Nashville, TN (United States); Dillman, Jonathan R. [University of Michigan Health System, C.S. Mott Children' s Hospital, Section of Pediatric Radiology, Ann Arbor, MI (United States); University of Michigan Health System, Department of Radiology, Ann Arbor, MI (United States); Mody, Rajen J. [University of Michigan Health System, C.S. Mott Children' s Hospital, Division of Pediatric Hematology-Oncology and Bone Marrow Transplantation, Ann Arbor, MI (United States); Strouse, Peter J. [University of Michigan Health System, C.S. Mott Children' s Hospital, Section of Pediatric Radiology, Ann Arbor, MI (United States)

    2008-04-15

    The kidneys are a site of extramedullary leukemic disease that can be readily detected by CT. To demonstrate the spectrum of CT findings in children with renal leukemic involvement. Twelve children were identified retrospectively as having renal leukemic involvement by contrast-enhanced CT of the abdomen. Contrast-enhanced CT images through the kidneys of each patient were reviewed by two pediatric radiologists. Pertinent imaging findings and renal lengths were documented. The electronic medical record was accessed to obtain relevant clinical and pathologic information. Five patients with renal leukemic involvement presented with multiple bilateral low-attenuation masses, while three patients demonstrated large areas of wedge-shaped and geographic low attenuation. Four other patients presented with unique imaging findings, including a solitary unilateral low-attenuation mass, solitary bilateral low-attenuation masses, multiple bilateral low-attenuation masses including unilateral large conglomerate masses, and bilateral areas of ill-defined parenchymal low attenuation. Two patients showed unilateral nephromegaly, while eight other patients showed bilateral nephromegaly. Two patients had normal size kidneys. Two patients had elevated serum creatinine concentrations at the time of imaging. Renal leukemic involvement in children can present with a variety of CT imaging findings. Focal renal abnormalities as well as nephromegaly are frequently observed. Most commonly, renal leukemic involvement does not appear to impair renal function. (orig.)

  19. Cone Beam CT vs. Fan Beam CT: A Comparison of Image Quality and Dose Delivered Between Two Differing CT Imaging Modalities.

    Science.gov (United States)

    Lechuga, Lawrence; Weidlich, Georg A

    2016-09-12

    A comparison of image quality and dose delivered between two differing computed tomography (CT) imaging modalities-fan beam and cone beam-was performed. A literature review of quantitative analyses for various image quality aspects such as uniformity, signal-to-noise ratio, artifact presence, spatial resolution, modulation transfer function (MTF), and low contrast resolution was generated. With these aspects quantified, cone beam computed tomography (CBCT) shows a superior spatial resolution to that of fan beam, while fan beam shows a greater ability to produce clear and anatomically correct images with better soft tissue differentiation. The results indicate that fan beam CT produces superior images to that of on-board imaging (OBI) cone beam CT systems, while providing a considerably less dose to the patient.

  20. Cone Beam CT vs. Fan Beam CT: A Comparison of Image Quality and Dose Delivered Between Two Differing CT Imaging Modalities

    Science.gov (United States)

    Weidlich, Georg A.

    2016-01-01

    A comparison of image quality and dose delivered between two differing computed tomography (CT) imaging modalities—fan beam and cone beam—was performed. A literature review of quantitative analyses for various image quality aspects such as uniformity, signal-to-noise ratio, artifact presence, spatial resolution, modulation transfer function (MTF), and low contrast resolution was generated. With these aspects quantified, cone beam computed tomography (CBCT) shows a superior spatial resolution to that of fan beam, while fan beam shows a greater ability to produce clear and anatomically correct images with better soft tissue differentiation. The results indicate that fan beam CT produces superior images to that of on-board imaging (OBI) cone beam CT systems, while providing a considerably less dose to the patient. PMID:27752404

  1. Comparison of virtual unenhanced CT images of the abdomen under different iodine flow rates.

    Science.gov (United States)

    Li, Yongrui; Li, Ye; Jackson, Alan; Li, Xiaodong; Huang, Ning; Guo, Chunjie; Zhang, Huimao

    2017-01-01

    To assess the effect of varying iodine flow rate (IFR) and iodine concentration on the quality of virtual unenhanced (VUE) images of the abdomen obtained with dual-energy CT. 94 subjects underwent unenhanced and triphasic contrast-enhanced CT scan of the abdomen, including arterial phase, portal venous phase, and delayed phase using dual-energy CT. Patients were randomized into 4 groups with different IFRs or iodine concentrations. VUE images were generated at 70 keV. The CT values, image noise, SNR and CNR of aorta, portal vein, liver, liver lesion, pancreatic parenchyma, spleen, erector spinae, and retroperitoneal fat were recorded. Dose-length product and effective dose for an examination with and without plain phase scan were calculated to assess the potential dose savings. Two radiologists independently assessed subjective image quality using a five-point scale. The Kolmogorov-Smirnov test was used first to test for normal distribution. Where data conformed to a normal distribution, analysis of variance was used to compare mean HU values, image noise, SNRs and CNRs for the 4 image sets. Where data distribution was not normal, a nonparametric test (Kruskal-Wallis test followed by stepwise step-down comparisons) was used. The significance level for all tests was 0.01 (two-sided) to allow for type 2 errors due to multiple testing. The CT numbers (HU) of VUE images showed no significant differences between the 4 groups (p > 0.05) or between different phases within the same group (p > 0.05). VUE images had equal or higher SNR and CNR than true unenhanced images. VUE images received equal or lower subjective image quality scores than unenhanced images but were of acceptable quality for diagnostic use. Calculated dose-length product and estimated dose showed that the use of VUE images in place of unenhanced images would be associated with a dose saving of 25%. VUE images can replace conventional unenhanced images. VUE images are not affected by varying iodine

  2. Efficient iterative image reconstruction algorithm for dedicated breast CT

    Science.gov (United States)

    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.

  3. Iterative model reconstruction: Improved image quality of low-tube-voltage prospective ECG-gated coronary CT angiography images at 256-slice CT

    Energy Technology Data Exchange (ETDEWEB)

    Oda, Seitaro, E-mail: seisei0430@nifty.com [Department of Cardiology, MedStar Washington Hospital Center, 110 Irving Street, NW, Washington, DC 20010 (United States); Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, 1-1-1 Honjyo, Chuo-ku, Kumamoto, 860-8556 (Japan); Weissman, Gaby, E-mail: Gaby.Weissman@medstar.net [Department of Cardiology, MedStar Washington Hospital Center, 110 Irving Street, NW, Washington, DC 20010 (United States); Vembar, Mani, E-mail: mani.vembar@philips.com [CT Clinical Science, Philips Healthcare, c595 Miner Road, Cleveland, OH 44143 (United States); Weigold, Wm. Guy, E-mail: Guy.Weigold@MedStar.net [Department of Cardiology, MedStar Washington Hospital Center, 110 Irving Street, NW, Washington, DC 20010 (United States)

    2014-08-15

    Objectives: To investigate the effects of a new model-based type of iterative reconstruction (M-IR) technique, the iterative model reconstruction, on image quality of prospectively gated coronary CT angiography (CTA) acquired at low-tube-voltage. Methods: Thirty patients (16 men, 14 women; mean age 52.2 ± 13.2 years) underwent coronary CTA at 100-kVp on a 256-slice CT. Paired image sets were created using 3 types of reconstruction, i.e. filtered back projection (FBP), a hybrid type of iterative reconstruction (H-IR), and M-IR. Quantitative parameters including CT-attenuation, image noise, and contrast-to-noise ratio (CNR) were measured. The visual image quality, i.e. graininess, beam-hardening, vessel sharpness, and overall image quality, was scored on a 5-point scale. Lastly, coronary artery segments were evaluated using a 4-point scale to investigate the assessability of each segment. Results: There was no significant difference in coronary arterial CT attenuation among the 3 reconstruction methods. The mean image noise of FBP, H-IR, and M-IR images was 29.3 ± 9.6, 19.3 ± 6.9, and 12.9 ± 3.3 HU, respectively, there were significant differences for all comparison combinations among the 3 methods (p < 0.01). The CNR of M-IR was significantly better than of FBP and H-IR images (13.5 ± 5.0 [FBP], 20.9 ± 8.9 [H-IR] and 39.3 ± 13.9 [M-IR]; p < 0.01). The visual scores were significantly higher for M-IR than the other images (p < 0.01), and 95.3% of the coronary segments imaged with M-IR were of assessable quality compared with 76.7% of FBP- and 86.9% of H-IR images. Conclusions: M-IR can provide significantly improved qualitative and quantitative image quality in prospectively gated coronary CTA using a low-tube-voltage.

  4. Choline-PET/CT for imaging prostate cancer; Cholin-PET/CT zur Bildgebung des Prostatakarzinoms

    Energy Technology Data Exchange (ETDEWEB)

    Krause, Bernd Joachim [Klinik- und Poliklinik fuer Nuklearmedizin, Klinikum rechts der Isar, Technische Univ. Muenchen (Germany); Treiber, U.; Schwarzenboeck, S.; Souvatzoglou, M. [Klinik fuer Urologie, Klinikum rechts der Isar, Technische Univ. Muenchen (Germany)

    2010-09-15

    PET and PET/CT using [{sup 11}C]- and [{sup 18}F]-labelled choline derivatives are increasingly being used for imaging of prostate cancer. The value of PET and PET/CT with [{sup 11}C]- and [{sup 18}F]-labelled choline derivates in biochemical recurrence of prostate cancer has been examined in many studies and demonstrates an increasing importance. Primary prostate cancer can be detected with moderate sensitivity using PET and PET/CT using [{sup 11}C]- and [{sup 18}F]-labelled choline derivatives - the differentiation between benign prostatic hyperplasia, prostatitis or high-grade intraepithelial neoplasia (HGPIN) is not always possible. At the present time [{sup 11}C]choline PET/CT is not recommended in the primary setting but may be utilized in clinically suspected prostate cancer with repeatedly negative prostate biopsies, in preparation of a focused re-biopsy. Promising results have been obtained for the use of PET and PET/CT with [{sup 11}C]- and [{sup 18}F]-labelled choline derivates in patients with biochemical recurrence. The detection rate of choline PET and PET/CT for local, regional, and distant recurrence in patients with a biochemical recurrence shows a linear correlation with PSA values at the time of imaging and reaches about 75% in patients with PSA > 3 ng/mL. At PSA values below 1 ng/mL, the recurrence can be diagnosed with choline PET/CT in approximately 1/3 of the patients. PET and PET/CT with [{sup 11}C]- and [{sup 18}F]choline derivates can be helpful for choosing a therapeutic strategy in the sense of an individualized treatment: since an early diagnosis of recurrence is crucial to the choice of optimal treatment. The localization of the site of recurrence - local recurrence, lymph node metastasis or systemic dissemination - has important influence on the therapy regimen. (orig.)

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

    Science.gov (United States)

    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. Interactive 3D Hybrid PET/CT Imaging in the Identification of Myocardial Viability in Patients After Myocardial Infarction: Feasibility Study and Clinical Implications

    Directory of Open Access Journals (Sweden)

    Yen-Wen Wu

    2008-06-01

    Conclusion: We present a protocol to acquire CT coronary angiography and PET data and to visualize 3D fused images with an interactive visualization interface. This image coregistration is potentially useful to facilitate the process of image interpretation and decision-making.

  7. Lacunarity analysis of spatial pattern in CT images of vertebral trabecular bone for assessing osteoporosis.

    Science.gov (United States)

    Dougherty, Geoffrey; Henebry, Geoffrey M

    2002-03-01

    The structural integrity of vertebral trabecular bone is determined by the continuity of its trabecular network and the size of the holes comprising its marrow space, both of which determine the apparent size of the marrow spaces in a transaxial CT image. A model-independent assessment of the trabeculation pattern was determined from the lacunarity of thresholded CT images. Using test images of lumbar vertebrae from human cadavers, acquired at different slice thicknesses, we determined that both median thresholding and local adaptive thresholding (using a 7 x 7 window) successfully segmented the grey-scale images. Lacunarity analysis indicated a multifractal nature to the images, and a range of marrow space sizes with significant structure around 14-18 mm(2). Preliminary studies of in vivo images from a clinical CT scanner indicate that lacunarity analysis can follow the pattern of bone loss in osteoporosis by monitoring the homogeneity of the marrow spaces, which is related to the connectivity of the trabecular bone network and the marrow space sizes. Although the patient sample was small, derived parameters such as the maximum deviation of the lacunarity from a neutral (fractal) model, and the maximum derivative of this deviation, seem to be sufficiently sensitive to distinguish a range of bone conditions. Our results suggest that these parameters, used with bone mineral density values, may have diagnostic value in characterizing osteoporosis and predicting fracture risk.

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

    Directory of Open Access Journals (Sweden)

    Jeremy Kenter

    2015-06-01

    Full Text Available 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.

  9. CT vaginography: a new CT technique for imaging of upper and middle vaginal fistulas.

    Science.gov (United States)

    Botsikas, Diomidis; Pluchino, Nicola; Kalovidouri, Anastasia; Platon, Alexandra; Montet, Xavier; Dallenbach, Patrick; Poletti, Pierre-Alexandre

    2017-05-01

    Different types of vaginal fistulas is a relatively uncommon condition in the Western world but very frequent in developing countries. In the past, conventional vaginography was the radiological examination of choice for exploring this condition. CT and MRI are now both used for this purpose. Our objective was to test the feasibility and to explore the potential role of a new CT imaging technique implementing vaginal introitus obstruction and opacification of the vagina with iodine contrast agent, to show patency of a fistula. We describe the technical protocol of CT-vaginography as performed in Geneva University Hospitals, including vaginal catheterization with a Foley catheter and obstruction of the introitus by inflating the balloon of the catheter. We also report three cases of patients with suspected vaginal fistula who underwent CT-vaginography. The examinations were technically successful. In one patient, it revealed the presence of fistulous pathways from the vaginal fornix along the bilateral infected surgical prostheses. In a second patient, it showed a fistula between the vagina and the necrotic cavity of a recurrent cervical cancer. In a third patient, it proved the absence of a suspected vaginal fistula. CT-vaginography is a technically feasible CT protocol that provides anatomical and functional information on clinically suspected vaginal fistulas. Advances in knowledge: After the abandon of conventional vaginography in the era of transaxial imaging, the current modalities of imaging vaginal fistulas provide excellent anatomical detail but less functional information concerning the permeability of a vaginal fistulous pathway. We propose the use of CT-vaginography, a technical protocol that we describe in detail.

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

    Science.gov (United States)

    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%.

  11. Automated delineation of stroke lesions using brain CT images

    Directory of Open Access Journals (Sweden)

    Céline R. Gillebert

    2014-01-01

    Full Text Available 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.

  12. Nasal polyps with metaplastic ossification: CT and MR imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yi Kyung; Kim, Hyung-Jin; Kim, Eunhee; Kim, Sung Tae [Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center, Seoul (Korea, Republic of); Kim, Jinna [Yonsei University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Chung, Seung-Kyu [Sungkyunkwan University School of Medicine, Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Seoul (Korea, Republic of); Ko, Young-Hyeh [Sungkyunkwan University School of Medicine, Department of Pathology, Samsung Medical Center, Seoul (Korea, Republic of)

    2010-12-15

    Metaplastic ossification is a rare event in nasal polyps. The purpose of this study was to review the computed tomography (CT) and magnetic resonance (MR) imaging findings of nasal polyps with metaplastic ossification. CT (n = 5) and MR (n = 3) images of five patients (four men and one woman; mean age, 59 years) with surgically proven nasal polyp with metaplastic ossification were retrospectively reviewed. The location and morphologic characteristics of metaplastic ossification were documented as well. All lesions were seen as lobulated (n = 3), ovoid (n = 1), or dumbbell-shaped (n = 1) benign-looking masses with a mean size of 3.7 cm (range, 2.4-6.5 cm), located unilaterally in the posterior nasal cavity and nasopharynx (n = 2), posterior nasoethmoidal tract (n = 2), and maxillary sinus and nasal cavity (n = 1). Compared with the brain stem, the soft tissue components of all lesions demonstrated isoattenuation on precontrast CT scans, slight hypointensity on T1-weighted MR images, and hyperintensity on T2-weighted MR images. On contrast-enhanced MR images, heterogeneous enhancement with marked peripheral enhancement was seen in two and homogeneous moderate enhancement in one. All lesions contained centrally located radiodense materials on CT scans, the shape of which was multiple clustered in three, single nodular in one, and single large lobulated in one. Although rare, metaplastic ossification can occur within nasal polyps. The possibility of its diagnosis may be raised when one sees a benign-looking sinonasal mass with centrally located radiodense materials on CT scans. MR imaging may be useful when mycetoma or inverted papilloma cannot be ruled out on CT scans. (orig.)

  13. The utilization of dual source CT in imaging of polytrauma

    Energy Technology Data Exchange (ETDEWEB)

    Nicolaou, S. [University of British Columbia, Vancouver General Hospital, Department of Radiology, 899 West 12th Avenue, Vancouver, British Columbia, V5Z1M9 (Canada)], E-mail: savvas.nicolaou@vch.ca; Eftekhari, A.; Sedlic, T.; Hou, D.J.; Mudri, M.J.; Aldrich, John; Louis, L. [University of British Columbia, Vancouver General Hospital, Department of Radiology, 899 West 12th Avenue, Vancouver, British Columbia, V5Z1M9 (Canada)

    2008-12-15

    Despite the growing role of imaging, trauma remains the leading cause of death in people below the age of 45 years in the western industrialized countries. Trauma has been touted as the largest epidemic in the 20th century. The advent of MDCT has been the greatest advance in trauma care in the last 25 years. However, there are still challenges in CT imaging of the polytrauma individual including time restraints, diagnostic errors, radiation dose effects and bridging the gap between anatomy and physiology. This article will analyze these challenges and provide possible solutions offered by the unique design of the dual source CT scanner.

  14. CT evaluation of congenital and acquired abnormalities of the azygos system.

    Science.gov (United States)

    Dudiak, C M; Olson, M C; Posniak, H V

    1991-03-01

    Congenital and acquired abnormalities may alter the anatomy, size, or position of the azygos system. Computed tomography is often able to depict these abnormalities and in many cases indicate the cause. In this article, the normal anatomy of the azygos system is discussed and examples of congenital and acquired abnormalities are presented.

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

    Directory of Open Access Journals (Sweden)

    Bruno Hochhegger

    2015-06-01

    Full Text Available 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.

  16. FDG PET/CT: EANM procedure guidelines for tumour imaging: version 2.0

    Energy Technology Data Exchange (ETDEWEB)

    Boellaard, Ronald; Hoekstra, Otto S. [VU University Medical Centre, Department of Radiology and Nuclear Medicine, Amsterdam (Netherlands); Delgado-Bolton, Roberto [University of La Rioja, Department of Diagnostic Imaging (Radiology) and Nuclear Medicine, San Pedro Hospital and Centre for Biomedical Research of La Rioja (CIBIR), Logrono, La Rioja (Spain); Oyen, Wim J.G.; Visser, Eric [Radboud University Nijmegen Medical Centre, Department of Radiology and Nuclear Medicine, Nijmegen (Netherlands); Giammarile, Francesco [Centre Hospitalier Universitaire de Lyon, Department of Nuclear Medicine, Lyon (France); Tatsch, Klaus [Municipal Hospital Karlsruhe Inc., Department of Nuclear Medicine, Karlsruhe (Germany); Eschner, Wolfgang [University of Cologne, Department of Nuclear Medicine, Cologne (Germany); Verzijlbergen, Fred J. [Erasmus Medical Center, Department of Nuclear Medicine, Rotterdam (Netherlands); Barrington, Sally F.; Pike, Lucy C. [King' s College London, King' s Health Partners, PET Imaging Centre, St Thomas' Hospital, Division of Imaging Sciences and Biomedical Engineering, London (United Kingdom); Weber, Wolfgang A. [Memorial Sloan Kettering Center, Department of Radiology, New York, NY (United States); Stroobants, Sigrid [Antwerp University Hospital, Department of Nuclear Medicine, Antwerp (Belgium); Delbeke, Dominique [Vanderbilt University Medical Center, Department of Radiology and Radiological Sciences, Nashville, TN (United States); Donohoe, Kevin J. [Beth Israel Deaconess Medical Center, Boston, MA (United States); Holbrook, Scott [Invivo Molecular Imaging LLC, Gray, TN (United States); Graham, Michael M. [University of Iowa, Department of Radiology, Iowa City, IA (United States); Testanera, Giorgio; Chiti, Arturo [Humanitas Clinical and Research Center, Department of Nuclear Medicine, Rozzano, MI (Italy); Zijlstra, Josee [VU University Medical Centre, Department of Hematology, Amsterdam (Netherlands); Hoekstra, Corneline J. [Jeroen Bosch Hospital, Department of Nuclear Medicine, Den Bosch (Netherlands); Pruim, Jan; Willemsen, Antoon [University Medical Centre Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen (Netherlands); Arends, Bertjan [Catharina Hospital, Department of Clinical Physics, Eindhoven (Netherlands); Kotzerke, Joerg [University Hospital Dresden, Clinic and Outpatient Clinic for Nuclear Medicine, Dresden (Germany); Bockisch, Andreas [University Hospital Essen, Clinic for Nuclear Medicine, Essen (Germany); Beyer, Thomas [Medical University of Vienna, Centre for Medical Physics and Biomedical Engineering, Vienna (Austria); Krause, Bernd J. [University Hospital Rostock, Department of Nuclear Medicine, Rostock (Germany)

    2014-12-02

    The purpose of these guidelines is to assist physicians in recommending, performing, interpreting and reporting the results of FDG PET/CT for oncological imaging of adult patients. PET is a quantitative imaging technique and therefore requires a common quality control (QC)/quality assurance (QA) procedure to maintain the accuracy and precision of quantitation. Repeatability and reproducibility are two essential requirements for any quantitative measurement and/or imaging biomarker. Repeatability relates to the uncertainty in obtaining the same result in the same patient when he or she is examined more than once on the same system. However, imaging biomarkers should also have adequate reproducibility, i.e. the ability to yield the same result in the same patient when that patient is examined on different systems and at different imaging sites. Adequate repeatability and reproducibility are essential for the clinical management of patients and the use of FDG PET/CT within multicentre trials. A common standardised imaging procedure will help promote the appropriate use of FDG PET/CT imaging and increase the value of publications and, therefore, their contribution to evidence-based medicine. Moreover, consistency in numerical values between platforms and institutes that acquire the data will potentially enhance the role of semiquantitative and quantitative image interpretation. Precision and accuracy are additionally important as FDG PET/CT is used to evaluate tumour response as well as for diagnosis, prognosis and staging. Therefore both the previous and these new guidelines specifically aim to achieve standardised uptake value harmonisation in multicentre settings. (orig.)

  17. Dynamic CT myocardial perfusion imaging: detection of ischemia in a porcine model with FFR verification

    Science.gov (United States)

    Fahmi, Rachid; Eck, Brendan L.; Vembar, Mani; Bezerra, Hiram G.; Wilson, David L.

    2014-03-01

    Dynamic cardiac CT perfusion (CTP) is a high resolution, non-invasive technique for assessing myocardial blood ow (MBF), which in concert with coronary CT angiography enable CT to provide a unique, comprehensive, fast analysis of both coronary anatomy and functional ow. We assessed perfusion in a porcine model with and without coronary occlusion. To induce occlusion, each animal underwent left anterior descending (LAD) stent implantation and angioplasty balloon insertion. Normal ow condition was obtained with balloon completely de ated. Partial occlusion was induced by balloon in ation against the stent with FFR used to assess the extent of occlusion. Prospective ECG-triggered partial scan images were acquired at end systole (45% R-R) using a multi-detector CT (MDCT) scanner. Images were reconstructed using FBP and a hybrid iterative reconstruction (iDose4, Philips Healthcare). Processing included: beam hardening (BH) correction, registration of image volumes using 3D cubic B-spline normalized mutual-information, and spatio-temporal bilateral ltering to reduce partial scan artifacts and noise variation. Absolute blood ow was calculated with a deconvolutionbased approach using singular value decomposition (SVD). Arterial input function was estimated from the left ventricle (LV) cavity. Regions of interest (ROIs) were identi ed in healthy and ischemic myocardium and compared in normal and occluded conditions. Under-perfusion was detected in the correct LAD territory and ow reduction agreed well with FFR measurements. Flow was reduced, on average, in LAD territories by 54%.

  18. CT and MR imaging of desmoplastic fibroblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Shuto, Rieko; Kiyosue, Hiro; Hori, Yuko; Miyake, Hidetoshi; Mori, Hiromu [Department of Radiology, Oita Medical University, Hasama-machi, Oita 879-5593 (Japan); Kawano, Katsunori [1. Department of Surgery, Oita Medical University, Hasama-machi, Oita 879-5593 (Japan)

    2002-10-01

    Desmoplastic fibroblastoma (collagenous fibroma) developing as a slowly enlarging lower abdominal mass is described. The lesion had inhomogeneous low signal intensity (SI) on T1-weighted images, and mixed SI as low SI within high SI on T2-weighted images. On post-contrast T1-weighted images, the mass showed inhomogeneous enhancement. Histologically, the areas showing low SI on both post-contrast T1- and T2-weighted images consisted of dense collagenous components and reduced cellularity compared with the areas showing high SI on them. (orig.)

  19. PET/CT Imaging and Radioimmunotherapy of Prostate Cancer

    DEFF Research Database (Denmark)

    Bouchelouche, Kirsten; Tagawa, Scott T; Goldsmith, Stanley J;

    2011-01-01

    Prostate cancer is a common cancer in men and continues to be a major health problem. Imaging plays an important role in the clinical management of patients with prostate cancer. An important goal for prostate cancer imaging is more accurate disease characterization through the synthesis...... disease (ideal for antigen access and antibody delivery). Furthermore, prostate cancer is also radiation sensitive. Prostate-specific membrane antigen is expressed by virtually all prostate cancers, and represents an attractive target for RIT. Antiprostate-specific membrane antigen RIT demonstrates...... of anatomic, functional, and molecular imaging information. Positron emission tomography (PET)/computed tomography (CT) in oncology is emerging as an important imaging tool. The most common radiotracer for PET/CT in oncology, (18)F-fluorodeoxyglucose (FDG), is not very useful in the imaging of prostate cancer...

  20. CT-diskography in patients with sciatica. Comparison with plain CT and MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Dullerud, R. [Ullevaal Univ. Hospital, Oslo (Norway). Section of Neuroradiology; Johansen, J.G. [Ullevaal Univ. Hospital, Oslo (Norway). Section of Neuroradiology

    1995-09-01

    The findings at CT-diskography (CT-D), including recording of the pain introduced at contrast injection, were compared with plain CT and MR imaging in 111 disks in 101 patients aged 18 to 68 years. Six disks which were normal at CT had normal CT-D and 5 of them had normal signal on MR imaging. The degree of annular degeneration and the depth of the annular tears were significantly associated with each other and with loss of disk height, but not with size or location of the hernias. Only the depth of the tears was significantly associated with loss of signal on MR. However, frequently complete annular tears and severe annular degeneration were seen in association with small bulges and hernias, even in disks with normal or slightly reduced signal on MR and with normal height. The type and intensity of the pain introduced were associated with each other and with the depth of the annular tears, but not with the degree of annular degeneration, size of the hernia or the MR signal intensity of the disks. Annular degeneration and tears on one hand, and the type and intensity of pain introduced on the other, see to be related rather than separate phenomena. (orig./MG).

  1. Automatic anatomy recognition on CT images with pathology

    Science.gov (United States)

    Huang, Lidong; Udupa, Jayaram K.; Tong, Yubing; Odhner, Dewey; Torigian, Drew A.

    2016-03-01

    Body-wide anatomy recognition on CT images with pathology becomes crucial for quantifying body-wide disease burden. This, however, is a challenging problem because various diseases result in various abnormalities of objects such as shape and intensity patterns. We previously developed an automatic anatomy recognition (AAR) system [1] whose applicability was demonstrated on near normal diagnostic CT images in different body regions on 35 organs. The aim of this paper is to investigate strategies for adapting the previous AAR system to diagnostic CT images of patients with various pathologies as a first step toward automated body-wide disease quantification. The AAR approach consists of three main steps - model building, object recognition, and object delineation. In this paper, within the broader AAR framework, we describe a new strategy for object recognition to handle abnormal images. In the model building stage an optimal threshold interval is learned from near-normal training images for each object. This threshold is optimally tuned to the pathological manifestation of the object in the test image. Recognition is performed following a hierarchical representation of the objects. Experimental results for the abdominal body region based on 50 near-normal images used for model building and 20 abnormal images used for object recognition show that object localization accuracy within 2 voxels for liver and spleen and 3 voxels for kidney can be achieved with the new strategy.

  2. Assessment of CT image quality using a Bayesian approach

    Science.gov (United States)

    Reginatto, M.; Anton, M.; Elster, C.

    2017-08-01

    One of the most promising approaches for evaluating CT image quality is task-specific quality assessment. This involves a simplified version of a clinical task, e.g. deciding whether an image belongs to the class of images that contain the signature of a lesion or not. Task-specific quality assessment can be done by model observers, which are mathematical procedures that carry out the classification task. The most widely used figure of merit for CT image quality is the area under the ROC curve (AUC), a quantity which characterizes the performance of a given model observer. In order to estimate AUC from a finite sample of images, different approaches from classical statistics have been suggested. The goal of this paper is to introduce task-specific quality assessment of CT images to metrology and to propose a novel Bayesian estimation of AUC for the channelized Hotelling observer (CHO) applied to the task of detecting a lesion at a known image location. It is assumed that signal-present and signal-absent images follow multivariate normal distributions with the same covariance matrix. The Bayesian approach results in a posterior distribution for the AUC of the CHO which provides in addition a complete characterization of the uncertainty of this figure of merit. The approach is illustrated by its application to both simulated and experimental data.

  3. Multi-delay arterial spin labeling perfusion MRI in moyamoya disease-comparison with CT perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rui [Chinese Academy of Sciences, State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Beijing (China); University of Chinese Academy of Sciences, Graduate School, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Los Angeles, CA (United States); Yu, Songlin [Capital Medical University, Department of Neurosurgery, Beijing Tiantan Hospital, Beijing (China); University of California Los Angeles, Department of Neurology, Los Angeles (United States); Alger, Jeffry R.; Wang, Danny J.J. [University of California Los Angeles, Department of Neurology, Los Angeles (United States); UCLA-Beijing Joint Center for Advanced Brain Imaging, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Los Angeles, CA (United States); Zuo, Zhentao; Wang, Bo [Chinese Academy of Sciences, State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Beijing (China); Chen, Juan [Beijing Hospital, Department of Radiology, Beijing (China); Wang, Rong; Zhao, Jizong [Capital Medical University, Department of Neurosurgery, Beijing Tiantan Hospital, Beijing (China); An, Jing [Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen (China); Xue, Rong [Chinese Academy of Sciences, State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Los Angeles, CA (United States)

    2014-05-15

    To present a multi-delay pseudo-continuous ASL (pCASL) protocol that offers simultaneous measurements of cerebral blood flow (CBF) and arterial transit time (ATT), and to study correlations between multi-delay pCASL and CT perfusion in moyamoya disease. A 4 post-labeling delay (PLD) pCASL protocol was applied on 17 patients with moyamoya disease who also underwent CT perfusion imaging. ATT was estimated using the multi-delay protocol and included in the calculation of CBF. ASL and CT perfusion images were rated for lesion severity/conspicuity. Pearson correlation coefficients were calculated across voxels between the two modalities in grey and white matter of each subject respectively and between normalized mean values of ASL and CT perfusion measures in major vascular territories. Significant associations between ASL and CT perfusion were detected using subjective ratings, voxel-wise analysis in grey and white matter and region of interest (ROI)-based analysis of normalized mean perfusion. The correlation between ASL CBF and CT perfusion was improved using the multi-delay pCASL protocol compared to CBF acquired at a single PLD of 2 s (P < 0.05). There is a correlation between perfusion data from ASL and CT perfusion imaging in patients with moyamoya disease. Multi-delay ASL can improve CBF quantification, which could be a prognostic imaging biomarker in patients with moyamoya disease. (orig.)

  4. CT image segmentation using FEM with optimized boundary condition.

    Directory of Open Access Journals (Sweden)

    Hiroyuki Hishida

    Full Text Available The authors propose a CT image segmentation method using structural analysis that is useful for objects with structural dynamic characteristics. Motivation of our research is from the area of genetic activity. In order to reveal the roles of genes, it is necessary to create mutant mice and measure differences among them by scanning their skeletons with an X-ray CT scanner. The CT image needs to be manually segmented into pieces of the bones. It is a very time consuming to manually segment many mutant mouse models in order to reveal the roles of genes. It is desirable to make this segmentation procedure automatic. Although numerous papers in the past have proposed segmentation techniques, no general segmentation method for skeletons of living creatures has been established. Against this background, the authors propose a segmentation method based on the concept of destruction analogy. To realize this concept, structural analysis is performed using the finite element method (FEM, as structurally weak areas can be expected to break under conditions of stress. The contribution of the method is its novelty, as no studies have so far used structural analysis for image segmentation. The method's implementation involves three steps. First, finite elements are created directly from the pixels of a CT image, and then candidates are also selected in areas where segmentation is thought to be appropriate. The second step involves destruction analogy to find a single candidate with high strain chosen as the segmentation target. The boundary conditions for FEM are also set automatically. Then, destruction analogy is implemented by replacing pixels with high strain as background ones, and this process is iterated until object is decomposed into two parts. Here, CT image segmentation is demonstrated using various types of CT imagery.

  5. CT scan of the brain (image)

    Science.gov (United States)

    ... CAT scan (computed tomography) is a much more sensitive imaging technique than x-ray, 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 ...

  6. CEREBRAL HYDATID DISEASE: CT AND MR IMAGING FINDINGS

    Directory of Open Access Journals (Sweden)

    Ajay

    2014-10-01

    Full Text Available OBJECTIVE: Cerebral hydatid disease is very rare, representing only 2% of all cerebral space occupying lesions even in the countries where the disease is endemic. The aim of this paper is to describe the characteristic features of cerebral hydatid disease in computed tomography (CT and magnetic resonance imaging (MRI. METHODS: Here is a case 25yr/m who presented to neurosurgery OPD with complaints of headache, vomiting, right sided weakness and seizures for 2 weeks. CT and MRI were the imaging modalities to reach the diagnosis which was pathologically confirmed postoperatively as hydatid disease. RESULTS: CT and MR imaging findings of E. granulosus lesions were well defined, smooth thin-walled, spherical, homogeneous cystic lesions with no contrast enhancement, no calcification, and no surrounding oedema. CONCLUSION: Although cystic cerebral hydatid disease is well demonstrated by CT and MR examinations, CT is superior in detecting calcification in the cyst, when present, MR is better in demonstrating cyst capsule, detecting multiplicity and defining the anatomic relationship of the lesion with the adjacent structures, and it is more helpful in surgical planning.

  7. Imaging of jaw with dental CT software program: Normal Anatomy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myong Gon; Seo, Kwang Hee; Jung, Hak Young; Sung, Nak Kwan; Chung, Duk Soo; Kim, Ok Dong [School of Medicine, Taegu Catholic University, Taegu (Korea, Republic of); Lee, Young Hwan [Taegu Armed Forces General Hospital, Taegu (Korea, Republic of)

    1994-07-15

    Dental CT software program can provide reformatted cross-sectional and panoramic images that cannot be obtained with conventional axial and direct coronal CT scan. The purpose of this study is to describe the method of the technique and to identify the precise anatomy of jaw. We evaluated 13 mandibles and 7 maxillae of 15 subjects without bony disease who were being considered for endosseous dental implants. Reformatted images obtained by the use of bone algorithm performed on GE HiSpeed Advantage CT scanner were retrospectively reviewed for detailed anatomy of jaw. Anatomy related to neurovascular bundle(mandibular foramen, inferior alveolar canal, mental foramen, canal for incisive artery, nutrient canal, lingual foramen and mylohyoid groove), muscular insertion(mylohyoid line, superior and inferior genial tubercle and digastric fossa) and other anatomy(submandibular fossa, sublingual fossa, contour of alveolar process, oblique line, retromolar fossa, temporal crest and retromolar triangle) were well delineated in mandible. In maxilla, anatomy related to neurovascular bundle(greater palatine foramen and groove, nasopalatine canal and incisive foramen) and other anatomy(alveolar process, maxillary sinus and nasal fossa) were also well delineated. Reformatted images using dental CT software program provided excellent delineation of the jaw anatomy. Therefore, dental CT software program can play an important role in the preoperative assessment of mandible and maxilla for dental implants and other surgical conditions.

  8. New frontiers in CT imaging of airway disease

    Energy Technology Data Exchange (ETDEWEB)

    Grenier, Philippe A.; Beigelman-Aubry, Catherine [Department of Radiology, University Pierre et Marie Curie, Paris (France); Fetita, Catalin; Preteux, Francoise [Institut National des Telecommunications, Department ARTEMIS, Evry (France); Brauner, Michel W. [Avicenne Hospital, UFR SMBH Paris XIII, Bobigny (France); Lenoir, Stephane [Institut Mutualiste Montsouris, Paris (France)

    2002-05-01

    Combining helical volumetric CT acquisition and thin-slice thickness during breath hold provides an accurate assessment of both focal and diffuse airway diseases. With multiple detector rows, compared with single-slice helical CT, multislice CT can cover a greater volume, during a simple breath hold, and with better longitudinal and in-plane spatial resolution and improved temporal resolution. The result in data set allows the generation of superior multiplanar and 3D images of the airways, including those obtained from techniques developed specifically for airway imaging, such as virtual bronchography and virtual bronchoscopy. Complementary CT evaluation at suspended or continuous full expiration is mandatory to detect air trapping that is a key finding for depicting an obstruction on the small airways. Indications for CT evaluation of the airways include: (a) detection of endobronchial lesions in patients with an unexplained hemoptysis; (b) evaluation of extent of tracheobronchial stenosis for planning treatment and follow-up; (c) detection of congenital airway anomalies revealed by hemoptysis or recurrent infection; (d) detection of postinfectious or postoperative airway fistula or dehiscence; and (e) diagnosis and assessment of extent of bronchiectasis and small airway disease. Improvement in image analysis technique and the use of spirometrically control of lung volume acquisition have made possible accurate and reproducible quantitative assessment of airway wall and lumen areas and lung density. This contributes to better insights in physiopathology of obstructive lung disease, particularly in chronic obstructive pulmonary disease and asthma. (orig.)

  9. Disease quantification on PET/CT images without object delineation

    Science.gov (United States)

    Tong, Yubing; Udupa, Jayaram K.; Odhner, Dewey; Wu, Caiyun; Fitzpatrick, Danielle; Winchell, Nicole; Schuster, Stephen J.; Torigian, Drew A.

    2017-03-01

    The derivation of quantitative information from images to make quantitative radiology (QR) clinically practical continues to face a major image analysis hurdle because of image segmentation challenges. This paper presents a novel approach to disease quantification (DQ) via positron emission tomography/computed tomography (PET/CT) images that explores how to decouple DQ methods from explicit dependence on object segmentation through the use of only object recognition results to quantify disease burden. The concept of an object-dependent disease map is introduced to express disease severity without performing explicit delineation and partial volume correction of either objects or lesions. The parameters of the disease map are estimated from a set of training image data sets. The idea is illustrated on 20 lung lesions and 20 liver lesions derived from 18F-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT scans of patients with various types of cancers and also on 20 NEMA PET/CT phantom data sets. Our preliminary results show that, on phantom data sets, "disease burden" can be estimated to within 2% of known absolute true activity. Notwithstanding the difficulty in establishing true quantification on patient PET images, our results achieve 8% deviation from "true" estimates, with slightly larger deviations for small and diffuse lesions where establishing ground truth becomes really questionable, and smaller deviations for larger lesions where ground truth set up becomes more reliable. We are currently exploring extensions of the approach to include fully automated body-wide DQ, extensions to just CT or magnetic resonance imaging (MRI) alone, to PET/CT performed with radiotracers other than FDG, and other functional forms of disease maps.

  10. "Conventional" CT images from spectral measurements

    Science.gov (United States)

    Rajbhandary, Paurakh L.; Pelc, Norbert J.

    2016-03-01

    Spectral imaging systems need to be able to produce "conventional" images, and it's been shown that systems with energy discriminating detectors can achieve higher CNR than conventional systems by optimal weighting. Combining measured data in energy bins (EBs) and also combining basis material images have previously been proposed, but there are no studies systematically comparing the two methods. In this paper, we analytically evaluate the two methods for systems with ideal photon counting detectors using CNR and beam hardening (BH) artifact as metrics. For a 120-kVp polychromatic simulations of a water phantom with low contrast inserts, the difference of the optimal CNR between the two methods for the studied phantom is within 2%. For a polychromatic spectrum, beam-hardening artifacts are noticeable in EB weighted images (BH artifact of 3.8% for 8 EB and 6.9% for 2 EB), while weighted basis material images are free of such artifacts.

  11. PET/CT imaging in head and neck tumors; PET-CT-Bildgebung bei Kopf-Hals-Tumoren

    Energy Technology Data Exchange (ETDEWEB)

    Roedel, R.; Palmedo, H.; Reichmann, K.; Reinhardt, M.J.; Biersack, H.J. [Universitaetsklinikum Bonn, Klinik und Poliklinik fuer Nuklearmedizin (Germany); Straehler-Pohl, H.J. [Universitaetsklinikum Bonn, Klinik und Poliklinik fuer Hals-, Nasen- und Ohrenheilkunde (Germany); Jaeger, U. [Universitaetsklinikum Bonn, Radiologische Klinik (Germany)

    2004-11-01

    To evaluate the usefulness of combined PET/CT examinations for detection of malignant tumors and their metastases in head and neck oncology. 51 patients received whole body scans on a dual modality PET/CT system. CT was performed without i.v. contrast. The results were compared concerning the diagnostic impact of native CT scan on FDG-PET images and the additional value of fused imaging. From 153 lesions were 97 classified as malignant on CT and 136 on FDG/PET images, as suspicious for malignancy in 33 on CT and 7 on FDG-PET and as benign in 23 on CT and 10 on FDG-PET. With combined PET/CT all primary and recurrent tumors could be found, the detection rate in patients with unknown primary tumors was 45%. Compared to PET or CT alone the sensitivity, specifity and accuracy could be significantly improved by means of combined PET/CT. Fused PET/CT imaging with [F18]-FDG and native CT-scanning enables accurate diagnosis in 93% of lesions and 90% of patients with head and neck oncology. (orig.) [German] Die Bestimmung der Wertigkeit der kombinierten PET-CT-Untersuchung zum Nachweis maligner Kopf-Hals-Tumoren und ihrer Metastasen. Bei 51 Patienten wurden Ganzkoerperuntersuchungen mit dem kombiniertem PET-CT-System durchgefuehrt. Die CT erfolgte ohne i.v. Kontrastmittelgabe. Die Ergebnisse wurden in ihrer diagnostischen Aussage einerseits getrennt fuer native CT- und FDG-PET-Bildgebung und andererseits fuer das fusionierte Bild verglichen. Von 153 Laesionen wurden 97 im CT und 136 im FDG-PET als maligne, 33 im CT und 7 im FDG-PET als malignitaetsverdaechtig, 23 im CT und 10 in der FDG-PET als benigne beurteilt. Die Anzahl der konkordanten Ergebnisse betrug 94 (61%), die der diskordanten 59 (39 %). Mit der PET-CT konnten alle Primaertumoren und Rezidive entdeckt werden, die Nachweisrate eines unbekannten Primaertumors betrug 45%. Im Vergleich zur alleinigen PET- oder CT-Untersuchung erhoehen sich bei der kombinierten PET-CT Sensitivitaet, Spezifitaet sowie die

  12. Comparison of Virtual Unenhanced Images Derived From Dual-Energy CT With True Unenhanced Images in Evaluation of Gallstone Disease.

    Science.gov (United States)

    Lee, Han A; Lee, Young Hwan; Yoon, Kwon-Ha; Bang, Dong-Ho; Park, Dong Eun

    2016-01-01

    The aim of this study was to compare gallstones on virtual unenhanced images and true unenhanced images acquired with dual-energy CT (DECT). We enrolled 112 patients with right upper quadrant pain and clinically suspected acute cholecystitis or gallstone who underwent DECT--including unenhanced, arterial, and portal phases. Eighty-three gallstones with composition proven by semiquantitative Fourier transform infrared spectroscopy from 45 patients who had undergone cholecystectomy (40 cholesterol gallstones from 21 patients, 43 calcium gallstones from 24 patients) were included. CT images were retrospectively evaluated for stone size, contrast-to-noise ratio (CNR) of gallstone to bile, and visibility and density of gallstones for each image set. The visibility of each type of stone was compared with a paired t test. Both cholesterol and calcium stones measured smaller on virtual unenhanced images than on true unenhanced images, yielding a lower sensitivity of virtual unenhanced images for detecting small gallstones. Mean CNR of cholesterol stones was 2.45 ± 1.32 versus 1.67 ± 1.55 (p gallstones, but true unenhanced images allow better visualization of calcium and small gallstones.

  13. Reformatted images improve the detection rate of acute traumatic subdural hematomas on brain CT compared with axial images alone.

    Science.gov (United States)

    Amrhein, Timothy J; Mostertz, William; Matheus, Maria Gisele; Maass-Bolles, Genevieve; Sharma, Komal; Collins, Heather R; Kranz, Peter G

    2017-02-01

    Subdural hematomas (SDHs) comprise a significant percentage of missed intracranial hemorrhage on axial brain CT. SDH detection rates could be improved with the addition of reformatted images. Though performed at some centers, the potential additional diagnostic sensitivity of reformatted images has not yet been investigated. The purpose of our study is to determine if the addition of coronal and sagittal reformatted images to an axial brain CT increases the sensitivity and specificity for detection of acute traumatic SDH. We retrospectively reviewed consecutive brain CTs acquired for acute trauma that contained new SDHs. An equivalent number of normal brain CTs served as control. Paired sets of images were created for each case: (1) axial images only ("axial only") and (2) axial, coronal, sagittal images ("reformat added"). Three readers interpreted both the axial only and companion reformat added for each case, separated by 1 month. Reading times and SDH detection rates were compared. One hundred SDH and 100 negative examinations were collected. Sensitivity and specificity for the axial-only scans were 75.7 and 94.3 %, respectively, compared with 88.3 and 98.3 % for reformat added. There was a 24.3 % false negative (missed SDH) rate with axial-only scans versus 11.7 % with reformat added (p = negatives by greater than 50 %. Reformatted images substantially reduce the number of missed SDHs compared with axial images alone.

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

    Science.gov (United States)

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

    2015-03-01

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

  15. Imaging of female pelvic malignancies regarding MRI, CT, and PET/CT. Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Brocker, Kerstin A.; Eichbaum, Michael; Sohn, Christof [Heidelberg Univ. (Germany). Dept. of Obstetrics and Gynecology; Alt, Celine D.; Kauczor, Hans-Ulrich; Hallscheidt, Peter [Heidelberg Univ. (Germany). Dept. of Diagnostic and Interventional Radiology

    2011-10-15

    The goal of this article is to provide an overview of diagnostic standard operating procedures for both clinical and imaging assessment of cervical and endometrial carcinoma, sarcoma of the uterus, and primary pelvic non-Hodgkin's lymphoma. The literature was reviewed for methods used to diagnose malignancies in the female pelvis with a special focus on the role of MRI as the imaging method of choice. Furthermore, CT findings and staging criteria for the mentioned malignancies are also provided. Whereas ultrasound still remains the imaging modality of choice in clinical practice for the early diagnosis of female pelvic malignancies, MRI is more frequently recognized as a diagnostic tool for its accuracy in tumor identification. MRI also plays a crucial role in the 3D pretreatment planning for brachytherapy especially in cervical cancer. In the future, PET/CT might achieve an important role for staging lymph nodes or distant metastases as well as tumor recurrence.

  16. SU-E-J-260: Quantitative Image Feature Analysis of Multiphase Liver CT for Hepatocellular Carcinoma (HCC) in Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Choi, W; Wang, J; Lu, W [University of Maryland School of Medicine, Baltimore, MD (United States); Kang, M [University of Maryland School of Medicine, Baltimore, MD (United States); Yeungnam University Medical Center, Daegu (Korea, Republic of)

    2015-06-15

    Purpose: To identify the effective quantitative image features (radiomics features) for prediction of response, survival, recurrence and metastasis of hepatocellular carcinoma (HCC) in radiotherapy. Methods: Multiphase contrast enhanced liver CT images were acquired in 16 patients with HCC on pre and post radiation therapy (RT). In this study, arterial phase CT images were selected to analyze the effectiveness of image features for the prediction of treatment outcome of HCC to RT. Response evaluated by RECIST criteria, survival, local recurrence (LR), distant metastasis (DM) and liver metastasis (LM) were examined. A radiation oncologist manually delineated the tumor and normal liver on pre and post CT scans, respectively. Quantitative image features were extracted to characterize the intensity distribution (n=8), spatial patterns (texture, n=36), and shape (n=16) of the tumor and liver, respectively. Moreover, differences between pre and post image features were calculated (n=120). A total of 360 features were extracted and then analyzed by unpaired student’s t-test to rank the effectiveness of features for the prediction of response. Results: The five most effective features were selected for prediction of each outcome. Significant predictors for tumor response and survival are changes in tumor shape (Second Major Axes Length, p= 0.002; Eccentricity, p=0.0002), for LR, liver texture (Standard Deviation (SD) of High Grey Level Run Emphasis and SD of Entropy, both p=0.005) on pre and post CT images, for DM, tumor texture (SD of Entropy, p=0.01) on pre CT image and for LM, liver (Mean of Cluster Shade, p=0.004) and tumor texture (SD of Entropy, p=0.006) on pre CT image. Intensity distribution features were not significant (p>0.09). Conclusion: Quantitative CT image features were found to be potential predictors of the five endpoints of HCC in RT. This work was supported in part by the National Cancer Institute Grant R01CA172638.

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

    Science.gov (United States)

    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.

  18. Noise properties of CT images reconstructed by use of constrained total-variation, data-discrepancy minimization

    DEFF Research Database (Denmark)

    Rose, Sean; Andersen, Martin S.; Sidky, Emil Y.;

    2015-01-01

    . Simulations demonstrate the iterative algorithms and the resulting image statistical properties for low-dose CT data acquired with sparse projection view angle sampling. Of particular interest is to quantify improvement of image statistical properties by use of the ML data fidelity term. Methods......-ray transmission data, is used to estimate the image statistical properties. The WLSQ and PL incremental algorithms are seen to reduce image variance as compared to that of LSQ without sacrificing image bias. The difference is also seen at few iterations-short of numerical convergence of the corresponding...

  19. TH-E-BRF-02: 4D-CT Ventilation Image-Based IMRT Plans Are Dosimetrically Comparable to SPECT Ventilation Image-Based Plans

    Energy Technology Data Exchange (ETDEWEB)

    Kida, S [UC Davis School of Medicine, Sacramento, CA (United States); University of Tokyo Hospital, Bunkyo, Tokyo (Japan); Bal, M [Philips Healthcare (Netherlands); Kabus, S [Philips Research, Hamburg (Germany); Loo, B [Stanford University, Stanford, CA (United States); Keall, P [University of Sydney, Camperdown (Australia); Yamamoto, T [UC Davis School of Medicine, Sacramento, CA (United States); Stanford University, Stanford, CA (United States)

    2014-06-15

    Purpose: An emerging lung ventilation imaging method based on 4D-CT can be used in radiotherapy to selectively avoid irradiating highly-functional lung regions, which may reduce pulmonary toxicity. Efforts to validate 4DCT ventilation imaging have been focused on comparison with other imaging modalities including SPECT and xenon CT. The purpose of this study was to compare 4D-CT ventilation image-based functional IMRT plans with SPECT ventilation image-based plans as reference. Methods: 4D-CT and SPECT ventilation scans were acquired for five thoracic cancer patients in an IRB-approved prospective clinical trial. The ventilation images were created by quantitative analysis of regional volume changes (a surrogate for ventilation) using deformable image registration of the 4D-CT images. A pair of 4D-CT ventilation and SPECT ventilation image-based IMRT plans was created for each patient. Regional ventilation information was incorporated into lung dose-volume objectives for IMRT optimization by assigning different weights on a voxel-by-voxel basis. The objectives and constraints of the other structures in the plan were kept identical. The differences in the dose-volume metrics have been evaluated and tested by a paired t-test. SPECT ventilation was used to calculate the lung functional dose-volume metrics (i.e., mean dose, V20 and effective dose) for both 4D-CT ventilation image-based and SPECT ventilation image-based plans. Results: Overall there were no statistically significant differences in any dose-volume metrics between the 4D-CT and SPECT ventilation imagebased plans. For example, the average functional mean lung dose of the 4D-CT plans was 26.1±9.15 (Gy), which was comparable to 25.2±8.60 (Gy) of the SPECT plans (p = 0.89). For other critical organs and PTV, nonsignificant differences were found as well. Conclusion: This study has demonstrated that 4D-CT ventilation image-based functional IMRT plans are dosimetrically comparable to SPECT ventilation image

  20. Osteosarcoma of the jaws: demographic and CT imaging features

    Science.gov (United States)

    Wang, S; Shi, H; Yu, Q

    2012-01-01

    Objective The aim of this study was to evaluate the patient demographic and CT imaging findings of primary osteosarcoma of the jaws. Methods 88 primary osteosarcomas of the jaws histopathologically diagnosed during 1997–2007 were reviewed. 21 cases of CT images were reviewed. Results Of 88 patients, 51 (58%) had tumours in the mandible and 37 (42%) in the maxilla. The mean age was 37.8 years (range 9–80 years). The male-to-female ratio was 1.32:1. The mean age of patients with mandibular lesions was 41.04 years and in those with maxillary lesions it was 33.3 years. CT imaging findings were available in 21 patients. In the maxilla (n = 9), all tumours (100%) arose from the alveolar ridge. In the mandible (n = 12), most tumours (9 cases, 75%), arose from the ramus and/or condyle. All except two lesions had the epicentrum within the medullary cavity of the involved bone. The presence of periosteal reaction was demonstrated in 13 cases (62%). Soft-tissue extension was present in 18 lesions (86%), with calcification identified in 13 (72%). Conclusions This study provides age, sex distribution, location and CT imaging features of primary osteosarcoma of the jaws. PMID:22074870

  1. CT and MR imaging findings of sphenoidal masses

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Shoki; Higano, Shuichi (Tohoku Univ., Sendai (Japan). School of Medicine); Ishii, Kiyoshi (and others)

    1994-07-01

    CT and MR imaging findings of 57 sphenoidal masses were retrospectively reviewed to assess the possibility of differential diagnosis between them. Various kinds of masses such as pituitary adenoma, epipharyngeal cancer, mucocele, chordoma, chondroma, chondrosarcoma, distant metastasis, multiple myeloma, fibrous dysplasia, craniopharyngioma, hemangiopericytoma, giant cell tumor, primary sphenoidal cancer, malignant melanoma, leukemia, histiocytosis X, and giant cell tumor were included in this series. CT scanning was performed in all cases using a spin-echo pulse sequence. The relative density of the masses, bony changes and calcification were evaluated on CT, and on MR images, signal intensity of the masses relative to the normal gray matter, contrast enhancement and extension/contour were evaluated. Although no single feature appeared to be specific to the masses, detection of calcification on CT, identification of the normal pituitary gland as deformed or displaced on T1-weighted images, signal intensity on T2-weighted images, and extension of the masses seemed to be useful and should be examined in terms of their ability to assist in differential diagnosis. Finally, accommodative classification of sphenoidal masses primarily based on presumed origin or mode of extension was attempted. (author).

  2. Software windows for the display of CT-images

    Energy Technology Data Exchange (ETDEWEB)

    Gell, G.; Sager, W.D.; Toelly, E.

    1983-03-01

    Software windows are a flexible and general method for defining arbitrary functions for the mapping of Hounsfield-numbers of CT-scans on to the grey levels of the display image. The method which is illustrated with the aid of a few examples has been implemented on an EMI viewing console.

  3. Computer aided detection of oral lesions on CT images

    Science.gov (United States)

    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.

  4. Hydatid disease of the spleen; Ultrasonography, CT and MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sinner, W.N. von; Stridbeck, H. (Dept. of Diagnostic Radiology, King Faisal Specialist Hospital, and Research Center, Riyadh (Saudi Arabia) Lund Univ. Hospital (Sweden))

    1992-09-01

    Seven patients with hydatid disease of the spleen were examined by radiography, ultrasound, CT, and in one case MR imaging. The observations were confirmed by patho-anatomic findings except in 2 patients where high indirect hemagglutination tests confirmed the diagnosis. (orig./MG).

  5. Combination of CT scanning and fluoroscopy imaging on a flat-panel CT scanner

    Science.gov (United States)

    Grasruck, M.; Gupta, R.; Reichardt, B.; Suess, Ch.; Schmidt, B.; Stierstorfer, K.; Popescu, S.; Brady, T.; Flohr, T.

    2006-03-01

    We developed and evaluated a prototype flat-panel detector based Volume CT (fpVCT) scanner. The fpVCT scanner consists of a Varian 4030CB a-Si flat-panel detector mounted in a multi slice CT-gantry (Siemens Medical Solutions). It provides a 25 cm field of view with 18 cm z-coverage at the isocenter. In addition to the standard tomographic scanning, fpVCT allows two new scan modes: (1) fluoroscopic imaging from any arbitrary rotation angle, and (2) continuous, time-resolved tomographic scanning of a dynamically changing viewing volume. Fluoroscopic imaging is feasible by modifying the standard CT gantry so that the imaging chain can be oriented along any user-selected rotation angle. Scanning with a stationary gantry, after it has been oriented, is equivalent to a conventional fluoroscopic examination. This scan mode enables combined use of high-resolution tomography and real-time fluoroscopy with a clinically usable field of view in the z direction. The second scan mode allows continuous observation of a timeevolving process such as perfusion. The gantry can be continuously rotated for up to 80 sec, with the rotation time ranging from 3 to 20 sec, to gather projection images of a dynamic process. The projection data, that provides a temporal log of the viewing volume, is then converted into multiple image stacks that capture the temporal evolution of a dynamic process. Studies using phantoms, ex vivo specimens, and live animals have confirmed that these new scanning modes are clinically usable and offer a unique view of the anatomy and physiology that heretofore has not been feasible using static CT scanning. At the current level of image quality and temporal resolution, several clinical applications such a dynamic angiography, tumor enhancement pattern and vascularity studies, organ perfusion, and interventional applications are in reach.

  6. Reliability of visual assessment of non-contrast CT, CT angiography source images and CT perfusion in patients with suspected ischemic stroke.

    Directory of Open Access Journals (Sweden)

    Tom van Seeters

    Full Text Available BACKGROUND AND PURPOSE: Good reliability of methods to assess the extent of ischemia in acute stroke is important for implementation in clinical practice, especially between observers with varying experience. Our aim was to determine inter- and intra-observer reliability of the 1/3 middle cerebral artery (MCA rule and the Alberta Stroke Program Early CT Score (ASPECTS for different CT modalities in patients suspected of acute ischemic stroke. METHODS: We prospectively included 105 patients with acute neurological deficit due to suspected acute ischemic stroke within 9 hours after symptom onset. All patients underwent non-contrast CT, CT perfusion and CT angiography on admission. All images were evaluated twice for presence of ischemia, ischemia with >1/3 MCA involvement, and ASPECTS. Four observers evaluated twenty scans twice for intra-observer agreement. We used kappa statistics and intraclass correlation coefficient to calculate agreement. RESULTS: Inter-observer agreement for the 1/3 MCA rule and ASPECTS was fair to good for non-contrast CT, poor to good for CT angiography source images, but excellent for all CT perfusion maps (cerebral blood volume, mean transit time, and predicted penumbra and infarct maps. Intra-observer agreement for the 1/3 MCA rule and ASPECTS was poor to good for non-contrast CT, fair to moderate for CT angiography source images, and good to excellent for all CT perfusion maps. CONCLUSION: Between observers with a different level of experience, agreement on the radiological diagnosis of cerebral ischemia is much better for CT perfusion than for non-contrast CT and CT angiography source images, and therefore CT perfusion is a very reliable addition to standard stroke imaging.

  7. Toxoplasma encephalitis in Haitian adults with acquired immunodeficiency syndrome: a clinical-pathologic-CT correlation

    Energy Technology Data Exchange (ETDEWEB)

    Post, M.J.D.; Chan, J.C.; Hensley, G.T.; Hoffman, T.A.; Moskowitz, L.B.; Lippmann, S.

    1983-05-01

    The clinical data, histologic findings, and computed tomographic (CT) abnormalities in eight adult Haitians with toxoplasma encephalitis were analyzed retrospectively. Diagnosis was established by identification of Toxoplasma gondii on autopsy in five and brain biopsy in three specimens and subsequently confirmed by the immunoperoxidase method. All these patiens, six of whom had been in the United States for 24 months or less, had severe idiopathic immunodeficiency syndrome. All were lymphopenic and six were on treatment for tuberculosis when the toxoplasma encephalitis developed. All patients were studied with CT when they developed an altered mental status and fever associated with seizures and/or focal neurologic deficits. Scans before treatment showed multiple intraparenchymal lesions in seven and a single lesion in the thalamus in one. Ring and/or nodular enhancement of the lesions was found in six and hypodense areas in two. Progressions of abnormalities occurred on serial studies. These CT findings that were best shown on axial and coronal thin-section double-dose contrast studies were useful but not diagnostically pathognomonic. In patients with similar clinical presentation CT is recommended to identify focal areas of involvement and to guide brain biopsy or excision so that prompt medical thereapy of this often lethal infection can be instituted.

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

    Energy Technology Data Exchange (ETDEWEB)

    Siewerdsen, Jeffrey H., E-mail: jeff.siewerdsen@jhu.edu [Department of Biomedical Engineering, Johns Hopkins University, Traylor Building, Room 718, 720 Rutland Avenue, Baltimore, MD 21205 (United States)

    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 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 surgical

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

    Science.gov (United States)

    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

  10. Fast and Automatic Ultrasound Simulation from CT Images

    OpenAIRE

    Weijian Cong; Jian Yang; Yue Liu; Yongtian Wang

    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...

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

    Science.gov (United States)

    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.

    2007-07-01

    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 2π 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 μe ± σe 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Abdelnour, A F [US Patent and Trademark Office, Alexandria, VA (United States); Nehmeh, S A [Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Pan, T [M.D. Anderson Cancer Center, Houston, TX (United States); Humm, J L [Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Vernon, P [GE Healthcare Technologies, Waukesha, WI (United States); Schoeder, H [Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Rosenzweig, K E [Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Mageras, G S [Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Yorke, E [Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Larson, S M [Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Erdi, Y E [Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    2007-07-21

    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 2{pi} 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 {mu}{sub e} {+-} {sigma}{sub e} 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.

  13. Multi-material decomposition of spectral CT images

    Science.gov (United States)

    Mendonça, Paulo R. S.; Bhotika, Rahul; Maddah, Mahnaz; Thomsen, Brian; Dutta, Sandeep; Licato, Paul E.; Joshi, Mukta C.

    2010-04-01

    Spectral Computed Tomography (Spectral CT), and in particular fast kVp switching dual-energy computed tomography, is an imaging modality that extends the capabilities of conventional computed tomography (CT). Spectral CT enables the estimation of the full linear attenuation curve of the imaged subject at each voxel in the CT volume, instead of a scalar image in Hounsfield units. Because the space of linear attenuation curves in the energy ranges of medical applications can be accurately described through a two-dimensional manifold, this decomposition procedure would be, in principle, limited to two materials. This paper describes an algorithm that overcomes this limitation, allowing for the estimation of N-tuples of material-decomposed images. The algorithm works by assuming that the mixing of substances and tissue types in the human body has the physicochemical properties of an ideal solution, which yields a model for the density of the imaged material mix. Under this model the mass attenuation curve of each voxel in the image can be estimated, immediately resulting in a material-decomposed image triplet. Decomposition into an arbitrary number of pre-selected materials can be achieved by automatically selecting adequate triplets from an application-specific material library. The decomposition is expressed in terms of the volume fractions of each constituent material in the mix; this provides for a straightforward, physically meaningful interpretation of the data. One important application of this technique is in the digital removal of contrast agent from a dual-energy exam, producing a virtual nonenhanced image, as well as in the quantification of the concentration of contrast observed in a targeted region, thus providing an accurate measure of tissue perfusion.

  14. Generation of synthetic CT data using patient specific daily MR image data and image registration

    Science.gov (United States)

    Melanie Kraus, Kim; Jäkel, Oliver; Niebuhr, Nina I.; Pfaffenberger, Asja

    2017-02-01

    To fully exploit the advantages of magnetic resonance imaging (MRI) for radiotherapy (RT) treatment planning, a method is required to overcome the problem of lacking electron density information. We aim to establish and evaluate a new method for computed tomography (CT) data generation based on MRI and image registration. The thereby generated CT data is used for dose accumulation. We developed a process flow based on an initial pair of rigidly co-registered CT and T2-weighted MR image representing the same anatomical situation. Deformable image registration using anatomical landmarks is performed between the initial MRI data and daily MR images. The resulting transformation is applied to the initial CT, thus fractional CT data is generated. Furthermore, the dose for a photon intensity modulated RT (IMRT) or intensity modulated proton therapy (IMPT) plan is calculated on the generated fractional CT and accumulated on the initial CT via inverse transformation. The method is evaluated by the use of phantom CT and MRI data. Quantitative validation is performed by evaluation of the mean absolute error (MAE) between the measured and the generated CT. The effect on dose accumulation is examined by means of dose-volume parameters. One patient case is presented to demonstrate the applicability of the method introduced here. Overall, CT data derivation lead to MAEs with a median of 37.0 HU ranging from 29.9 to 66.6 HU for all investigated tissues. The accuracy of image registration showed to be limited in the case of unexpected air cavities and at tissue boundaries. The comparisons of dose distributions based on measured and generated CT data agree well with the published literature. Differences in dose volume parameters kept within 1.6% and 3.2% for photon and proton RT, respectively. The method presented here is particularly suited for application in adaptive RT in current clinical routine, since only minor additional technical equipment is required.

  15. Impact of CT attenuation correction method on quantitative respiratory-correlated (4D) PET/CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Nyflot, Matthew J., E-mail: nyflot@uw.edu [Department of Radiation Oncology, University of Washington, Seattle, Washington 98195-6043 (United States); Lee, Tzu-Cheng [Department of Bioengineering, University of Washington, Seattle, Washington 98195-6043 (United States); Alessio, Adam M.; Kinahan, Paul E. [Department of Radiology, University of Washington, Seattle, Washington 98195-6043 (United States); Wollenweber, Scott D.; Stearns, Charles W. [GE Healthcare, Waukesha, Wisconsin 53188 (United States); Bowen, Stephen R. [Department of Radiation Oncology, University of Washington, Seattle, Washington 98195-6043 and Department of Radiology, University of Washington, Seattle, Washington 98195-6043 (United States)

    2015-01-15

    Purpose: Respiratory-correlated positron emission tomography (PET/CT) 4D PET/CT is used to mitigate errors from respiratory motion; however, the optimal CT attenuation correction (CTAC) method for 4D PET/CT is unknown. The authors performed a phantom study to evaluate the quantitative performance of CTAC methods for 4D PET/CT in the ground truth setting. Methods: A programmable respiratory motion phantom with a custom movable insert designed to emulate a lung lesion and lung tissue was used for this study. The insert was driven by one of five waveforms: two sinusoidal waveforms or three patient-specific respiratory waveforms. 3DPET and 4DPET images of the phantom under motion were acquired and reconstructed with six CTAC methods: helical breath-hold (3DHEL), helical free-breathing (3DMOT), 4D phase-averaged (4DAVG), 4D maximum intensity projection (4DMIP), 4D phase-matched (4DMATCH), and 4D end-exhale (4DEXH) CTAC. Recovery of SUV{sub max}, SUV{sub mean}, SUV{sub peak}, and segmented tumor volume was evaluated as RC{sub max}, RC{sub mean}, RC{sub peak}, and RC{sub vol}, representing percent difference relative to the static ground truth case. Paired Wilcoxon tests and Kruskal–Wallis ANOVA were used to test for significant differences. Results: For 4DPET imaging, the maximum intensity projection CTAC produced significantly more accurate recovery coefficients than all other CTAC methods (p < 0.0001 over all metrics). Over all motion waveforms, ratios of 4DMIP CTAC recovery were 0.2 ± 5.4, −1.8 ± 6.5, −3.2 ± 5.0, and 3.0 ± 5.9 for RC{sub max}, RC{sub peak}, RC{sub mean}, and RC{sub vol}. In comparison, recovery coefficients for phase-matched CTAC were −8.4 ± 5.3, −10.5 ± 6.2, −7.6 ± 5.0, and −13.0 ± 7.7 for RC{sub max}, RC{sub peak}, RC{sub mean}, and RC{sub vol}. When testing differences between phases over all CTAC methods and waveforms, end-exhale phases were significantly more accurate (p = 0.005). However, these differences were driven by

  16. Improved diagnosis of actively bleeding aneurysm on CT angiography using delayed CT images

    Energy Technology Data Exchange (ETDEWEB)

    Kathuria, Sudhir, E-mail: skathur2@jhmi.edu [Division of Interventional Neuroradiology, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Division of Interventional Neuroradiology, Department of Neurology and Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Deveikis, John P.; Westesson, Per-Lennart [Division of Diagnostic and Interventional Neuroradiology, Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY 14642 (United States); Gandhi, Dheeraj [Division of Interventional Neuroradiology, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Division of Interventional Neuroradiology, Department of Neurology and Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD (United States)

    2011-08-15

    Computed tomographic angiography (CTA) is being increasingly utilized in the non-invasive diagnosis of aneurysmal subarachnoid hemorrhage (SAH). There are emerging reports of diagnosis of active aneurysmal bleeding on CTA, furthering our understanding of imaging features of active extravasation on cross-sectional studies. We demonstrate imaging characteristics of two such cases of active contrast extravasation from intracranial aneurysms. Additionally, we demonstrate that delayed CT images greatly improve the confidence of this diagnosis by demonstrating pooling of contrast in the subarachnoid space. Prompt recognition and management can improve prognosis of this potentially lethal condition.

  17. Aerial Image over Flint Hills National Wildlife Refuge, Acquired on March 22, 1950 (Frame 1656)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Georeferenced image, acquired on March 22, 1950, over a portion of the Flint Hills National Wildlife Refuge. Image covers the eastern portion of the refuge including...

  18. Aerial Image over Ouray National Wildlife Refuge, Acquired on August 27, 1965 (Frame 131)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Georeferenced image, acquired on August 27, 1965 over a portion of the Ouray National Wildlife Refuge. Image covers the northern portion of the refuge including...

  19. Aerial Image over Flint Hills National Wildlife Refuge, Acquired on April 14, 1948 (Frame 1155)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Georeferenced image, acquired on April 14, 1948, over a portion of the Flint Hills National Wildlife Refuge. Image covers the eastern portion of the refuge including...

  20. [CT coronary angiography: indications, image acquisition, and interpretation].

    Science.gov (United States)

    Schoepf, U J; Thilo, C; Fernández, M J; Costello, P

    2008-01-01

    Intense scientific and clinical evaluation have brought about great improvements in cardiac CT. This is no longer merely an experimental technique, rather it has become a clinical application that is ready to fulfill its promise of replacing invasive cardiac catheterization in certain patient populations. Among the proven indications is the evaluation of patients with atypical chest pain, the morphological evaluation of the coronary arteries in cases of suspected congenital anomalies, and before surgical intervention, as well as the evaluation of coronary revascularizations. The use of CT angiography for the exhaustive evaluation of cardiac and non-cardiac pathology in patients with acute chest pain in the emergency department is currently being investigated. Because the heart is continuously moving, CT coronary angiography represents a greater technical challenge than other applications of CT. On the other hand, rapid technical development requires acquisition protocols to be adjusted constantly. However, users that know the general techniques of computed tomography can overcome these challenges. The aim of this article is to provide those interested and involved in CT angiography with a manual to enable them to follow our method step by step. We include considerations regarding the correct selection of patients, patient medication, radiological protection, contrast enhancement, acquisition and reconstruction parameters, image display, image analysis techniques, and the radiological report. Our recommendations are based on our experience, which runs from the evolution of multiple-row detector CT scanners for cardiac applications from its beginnings to the most modern presentations of advanced acquisition modalities, including dual-source CT, which we consider to be the precursor of this test in routine clinical practice.

  1. Reconstruction of CT images by the Bayes- back projection method

    CERN Document Server

    Haruyama, M; Takase, M; Tobita, H

    2002-01-01

    In the course of research on quantitative assay of non-destructive measurement of radioactive waste, the have developed a unique program based on the Bayesian theory for reconstruction of transmission computed tomography (TCT) image. The reconstruction of cross-section images in the CT technology usually employs the Filtered Back Projection method. The new imaging reconstruction program reported here is based on the Bayesian Back Projection method, and it has a function of iterative improvement images by every step of measurement. Namely, this method has the capability of prompt display of a cross-section image corresponding to each angled projection data from every measurement. Hence, it is possible to observe an improved cross-section view by reflecting each projection data in almost real time. From the basic theory of Baysian Back Projection method, it can be not only applied to CT types of 1st, 2nd, and 3rd generation. This reported deals with a reconstruction program of cross-section images in the CT of ...

  2. Head CT: Image quality improvement of posterior fossa and radiation dose reduction with ASiR - comparative studies of CT head examinations

    Energy Technology Data Exchange (ETDEWEB)

    Guzinski, Maciej; Waszczuk, Lukasz; Sasiadek, Marek J. [Wroclaw Medical University, Department of General Radiology, Interventional Radiology and Neuroradiology, Wroclaw (Poland)

    2016-10-15

    To evaluate head CT protocol developed to improve visibility of the brainstem and cerebellum, lower bone-related artefacts in the posterior fossa and maintain patient radioprotection. A paired comparison of head CT performed without Adaptive Statistical Iterative Reconstruction (ASiR) and a clinically indicated follow-up with 40 % ASiR was acquired in one group of 55 patients. Patients were scanned in the axial mode with different scanner settings for the brain and the posterior fossa. Objective image quality analysis was performed with signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Subjective image quality analysis was based on brain structure visibility and evaluation of the artefacts. We achieved 19 % reduction of total DLP and significantly better image quality of posterior fossa structures. SNR for white and grey matter in the cerebellum were 34 % to 36 % higher, respectively, CNR was improved by 142 % and subjective analyses were better for images with ASiR. When imaging parameters are set independently for the brain and the posterior fossa imaging, ASiR has a great potential to improve CT performance: image quality of the brainstem and cerebellum is improved, and radiation dose for the brain as well as total radiation dose are reduced. (orig.)

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

    Science.gov (United States)

    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.

  4. Clinical feasibility of {sup 90}Y digital PET/CT for imaging microsphere biodistribution following radioembolization

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Chadwick L.; Binzel, Katherine; Zhang, Jun; Knopp, Michael V. [The Ohio State University Wexner Medical Center, Wright Center of Innovation in Biomedical Imaging, Department of Radiology, Columbus, OH (United States); Wuthrick, Evan J. [The Ohio State University Wexner Medical Center, Department of Radiation Oncology, Columbus, OH (United States)

    2017-07-15

    The purpose of this study was to evaluate the clinical feasibility of next generation solid-state digital photon counting PET/CT (dPET/CT) technology and imaging findings in patients following {sup 90}Y microsphere radioembolization in comparison with standard of care (SOC) bremsstrahlung SPECT/CT (bSPECT/CT). Five patients underwent SOC {sup 90}Y bremsstrahlung imaging immediately following routine radioembolization with 3.5 ± 1.7 GBq of {sup 90}Y-labeled glass microspheres. All patients also underwent dPET/CT imaging at 29 ± 11 h following radioembolization. Matched pairs comparison was used to compare image quality, image contrast and {sup 90}Y biodistribution between dPET/CT and bSPECT/CT images. Volumetric assessments of {sup 90}Y activity using different isocontour thresholds on dPET/CT and bSPECT/CT images were also compared. Digital PET/CT consistently provided better visual image quality and {sup 90}Y-to-background image contrast while depicting {sup 90}Y biodistribution than bSPECT/CT. Isocontour volumetric assessment using a 1% threshold precisely outlined {sup 90}Y activity and the treatment volume on dPET/CT images, whereas a more restrictive 20% threshold on bSPECT/CT images was needed to obtain comparable treatment volumes. The use of a less restrictive 10% threshold isocontour on bSPECT/CT images grossly overestimated the treatment volume when compared with the 1% threshold on dPET/CT images. Digital PET/CT is clinically feasible for the assessment of {sup 90}Y microsphere biodistribution following radioembolization, and provides better visual image quality and image contrast than routine bSPECT/CT with comparable acquisition times. With further optimization and clinical validation, dPET technology may allow faster and more accurate imaging-based assessment of {sup 90}Y microsphere biodistribution. (orig.)

  5. Accuracy and feasibility of three different methods for software-based image fusion in whole-body PET and CT.

    Science.gov (United States)

    Putzer, Daniel; Henninger, Benjamin; Kovacs, Peter; Uprimny, Christian; Kendler, Dorota; Jaschke, Werner; Bale, Reto J

    2016-06-01

    Even as PET/CT provides valuable diagnostic information in a great number of clinical indications, availability of hybrid PET/CT scanners is mainly limited to clinical centers. A software-based image fusion would facilitate combined image reading of CT and PET data sets if hardware image fusion is not available. To analyze the relevance of retrospective image fusion of separately acquired PET and CT data sets, we studied the accuracy, practicability and reproducibility of three different image registration techniques. We evaluated whole-body 18F-FDG-PET and CT data sets of 71 oncologic patients. Images were fused retrospectively using Stealth Station System, Treon (Medtronic Inc., Louisville, CO, USA) equipped with Cranial4 Software. External markers fixed to a vacuum mattress were used as reference for exact repositioning. Registration was repeated using internal anatomic landmarks and Automerge software, assessing accuracy for all three methods, measuring distances of liver representation in CT and PET with reference to a common coordinate system. On first measurement of image fusions with external markers, 53 were successful, 16 feasible and 2 not successful. Using anatomic landmarks, 42 were successful, 26 feasible and 3 not successful. Using Automerge Software only 13 were successful. The mean distance between center points in PET and CT was 7.69±4.96 mm on first, and 7.65±4.2 mm on second measurement. Results with external markers correlate very well and inaccuracies are significantly lower (Pfusion cost-effectively and significantly less time, posing an attractive alternative for PET/CT interpretation when a hybrid scanner is not available.

  6. Esthesioneuroblastoma methods of intracranial extension: CT and MR imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Tian; Xu, Yi-Kai; Jia, Fei-Ge; Yang, Rui-Meng; Feng, Jie; Ye, Xiang-Hua; Qiu, Ying-Wei [Southern Medical University, Department of Medical Imaging Center, Nan Fang Hospital, Guangzhou, Guangdong (China); Li, Long [Chinese People' s Armed Police Forces, Department of Radiology, Guangdong Provincial Corps Hospital, Guangzhou (China); Duan, Gang; Wu, Yuan-Kui [Southern Medical University, Department of Radiology, Nan Fang Hospital, Guangzhou (China); Li, Hua-Yu [No. 458 Hospital of PLA, Department of Medical Imaging Center, Guangzhou (China)

    2009-12-15

    Esthesioneuroblastoma (ENB) is an aggressive neuroectodermal malignancy in the upper nasal cavity with local infiltration and lymphatic or hematogenous metastasis. The purpose of this paper is to document three types of direct intracranial extensions by ENB using computed tomography (CT) and magnetic resonance imaging (MRI). Eleven patients with pathologically confirmed ENB were admitted in our hospital between December 2002 and December 2008. Their magnetic resonance (MR; n = 10) and CT (n = 8) images were retrospectively reviewed, and particular attention was paid to tumor location and extension, enhancement pattern, cervical lymph node metastasis, and Kadish stage. The majority of patients were male (8/11) with Kadish stage C tumor (10/11). Three types of direct intracranial extension by ENBs were put forward according to their MR and CT findings. The primary tumors were well-defined soft-tissue masses centered in the roof of the nasal cavity eroding into the paranasal sinuses (11/11), the contralateral nasal cavity (4/11), the cranial cavity (5/11), and the fossa orbitalis (3/11). The tumor parenchyma were hypointensity on T1-weighted images, heterogeneous hyperintensity on T2-weighted images, and isodensity or slight hyperdensity on CT images with scattered necroses (4/11) and marginal cysts(4/11). Their enhancements were significant and inhomogeneous. Cervical lymph nodes metastases were observed in four patients (4/11), but no pathologically proved distant metastasis was observed. Three types of direct intracranial extensions by ENB can be found on CT and MRI: cranio-orbital-nasal-communicating ENB, cranio-nasal-communicating ENB, and orbital-nasal-communicating ENB. (orig.)

  7. Registration of PET and CT images based on multiresolution gradient of mutual information demons algorithm for positioning esophageal cancer patients.

    Science.gov (United States)

    Jin, Shuo; Li, Dengwang; Wang, Hongjun; Yin, Yong

    2013-01-07

    Accurate registration of 18F-FDG PET (positron emission tomography) and CT (computed tomography) images has important clinical significance in radiation oncology. PET and CT images are acquired from (18)F-FDG PET/CT scanner, but the two acquisition processes are separate and take a long time. As a result, there are position errors in global and deformable errors in local caused by respiratory movement or organ peristalsis. The purpose of this work was to implement and validate a deformable CT to PET image registration method in esophageal cancer to eventually facilitate accurate positioning the tumor target on CT, and improve the accuracy of radiation therapy. Global registration was firstly utilized to preprocess position errors between PET and CT images, achieving the purpose of aligning these two images on the whole. Demons algorithm, based on optical flow field, has the features of fast process speed and high accuracy, and the gradient of mutual information-based demons (GMI demons) algorithm adds an additional external force based on the gradient of mutual information (GMI) between two images, which is suitable for multimodality images registration. In this paper, GMI demons algorithm was used to achieve local deformable registration of PET and CT images, which can effectively reduce errors between internal organs. In addition, to speed up the registration process, maintain its robustness, and avoid the local extremum, multiresolution image pyramid structure was used before deformable registration. By quantitatively and qualitatively analyzing cases with esophageal cancer, the registration scheme proposed in this paper can improve registration accuracy and speed, which is helpful for precisely positioning tumor target and developing the radiation treatment planning in clinical radiation therapy application.

  8. The algorithm study for using the back propagation neural network in CT image segmentation

    Science.gov (United States)

    Zhang, Peng; Liu, Jie; Chen, Chen; Li, Ying Qi

    2017-01-01

    Back propagation neural network(BP neural network) is a type of multi-layer feed forward network which spread positively, while the error spread backwardly. Since BP network has advantages in learning and storing the mapping between a large number of input and output layers without complex mathematical equations to describe the mapping relationship, it is most widely used. BP can iteratively compute the weight coefficients and thresholds of the network based on the training and back propagation of samples, which can minimize the error sum of squares of the network. Since the boundary of the computed tomography (CT) heart images is usually discontinuous, and it exist large changes in the volume and boundary of heart images, The conventional segmentation such as region growing and watershed algorithm can't achieve satisfactory results. Meanwhile, there are large differences between the diastolic and systolic images. The conventional methods can't accurately classify the two cases. In this paper, we introduced BP to handle the segmentation of heart images. We segmented a large amount of CT images artificially to obtain the samples, and the BP network was trained based on these samples. To acquire the appropriate BP network for the segmentation of heart images, we normalized the heart images, and extract the gray-level information of the heart. Then the boundary of the images was input into the network to compare the differences between the theoretical output and the actual output, and we reinput the errors into the BP network to modify the weight coefficients of layers. Through a large amount of training, the BP network tend to be stable, and the weight coefficients of layers can be determined, which means the relationship between the CT images and the boundary of heart.

  9. Hybrid detection of lung nodules on CT scan images

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Lin; Tan, Yongqiang; Schwartz, Lawrence H.; Zhao, Binsheng, E-mail: bz2166@columbia.edu [Department of Radiology, Columbia University Medical Center, 630 West 168th Street, New York, New York 10032 (United States)

    2015-09-15

    Purpose: The diversity of lung nodules poses difficulty for the current computer-aided diagnostic (CAD) schemes for lung nodule detection on computed tomography (CT) scan images, especially in large-scale CT screening studies. We proposed a novel CAD scheme based on a hybrid method to address the challenges of detection in diverse lung nodules. Methods: The hybrid method proposed in this paper integrates several existing and widely used algorithms in the field of nodule detection, including morphological operation, dot-enhancement based on Hessian matrix, fuzzy connectedness segmentation, local density maximum algorithm, geodesic distance map, and regression tree classification. All of the adopted algorithms were organized into tree structures with multi-nodes. Each node in the tree structure aimed to deal with one type of lung nodule. Results: The method has been evaluated on 294 CT scans from the Lung Image Database Consortium (LIDC) dataset. The CT scans were randomly divided into two independent subsets: a training set (196 scans) and a test set (98 scans). In total, the 294 CT scans contained 631 lung nodules, which were annotated by at least two radiologists participating in the LIDC project. The sensitivity and false positive per scan for the training set were 87% and 2.61%. The sensitivity and false positive per scan for the testing set were 85.2% and 3.13%. Conclusions: The proposed hybrid method yielded high performance on the evaluation dataset and exhibits advantages over existing CAD schemes. We believe that the present method would be useful for a wide variety of CT imaging protocols used in both routine diagnosis and screening studies.

  10. Implementation of efficient image reconstruction for CT

    Institute of Scientific and Technical Information of China (English)

    Jie Liu; Guangfei Wang

    2005-01-01

    @@ The operational procedures for efficiently reconstructing the two-dimensional image of a body by the filtered back projection are described in this paper. The projections are interpolated for four times of original projection by zero-padding the original projection in frequency-domain and then inverse fast Fourier transform (FFT) is taken to improve accuracy.

  11. PET/CT and Bremsstrahlung Imaging After 90Y DOTANOC Therapy for Rectal Net With Liver Metastases.

    Science.gov (United States)

    Abdülrezzak, Ümmühan; Kula, Mustafa; Tutuş, Ahmet; Buyukkaya, Fikret; Karaca, Halit

    2015-10-01

    Peptide receptor radionuclide therapy with Lu or Y is promising with successful results in somatostatin receptor-positive tumors. In all radiation therapies, knowledge of the radiation dose received by the target, and other organs in the body is essential to evaluate the risks and benefits of any procedure. We report a case of liver metastases from a rectal neuroendocrine tumor, which was treated with Y DOTANOC. Posttreatment whole-body planar images were acquired through Bremsstrahlung radiations of Y on a γ-camera, and thoracolumbar PET/CT images were acquired on PET.

  12. Dysplastic gangliocytoma (Lhermitte-Duclos disease): CT and MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Vieco, P.T.; Del Carpio-O' Donovan, R.; Melanson, D. (Montreal Neurological Hospital, PQ (Canada). Dept. of Diagnostic Radiology); Montes, J. (Montreal Children' s Hospital, PQ (Canada). Dept. of Neurosurgery); O' Gorman, A.M. (Montreal Children' s Hospital, PQ (Canada). Dept. of Radiology); Meagher-Villemure, K. (Montreal Children' s Hospital, PQ (Canada). Dept. of Pathology)

    1992-09-01

    Dysplastic gangliocytoma (Lhermitte-Duclos disease) is a rare entity. Usually presenting as a posterior fossa mass, dyplastic gangliocytoma is not a true neoplasm but a hard-to-characterize lesion that may represent an abnormality of cell migration or a phacomatosis. Previous reports of CT findings are rare in the radiologic literature, and high-field (1.5 Tesla) MR images have never been described in the pediatric age group. We present a case of dysplastic gangliocytoma in a one-year-old boy with CT and MR findings. (orig.).

  13. Image reconstruction for view-limited x-ray CT in baggage scanning

    Science.gov (United States)

    Mandava, Sagar; Coccarelli, David; Greenberg, Joel A.; Gehm, Michael E.; Ashok, Amit; Bilgin, Ali

    2017-05-01

    X-ray CT based baggage scanners are widely used in security applications. Recently, there has been increased interest in view-limited systems which can improve the scanning throughput while maintaining the threat detection performance. However as very few view angles are acquired in these systems, the image reconstruction problem is challenging. Standard reconstruction algorithms such as the filtered backprojection create strong artifacts when working with view-limited data. In this work, we study the performance of a variety of reconstruction algorithms for both single and multi-energy view-limited systems.

  14. A study on the effect of CT imaging acquisition parameters on lung nodule image interpretation

    Science.gov (United States)

    Yu, Shirley J.; Wantroba, Joseph S.; Raicu, Daniela S.; Furst, Jacob D.; Channin, David S.; Armato, Samuel G., III

    2009-02-01

    Most Computer-Aided Diagnosis (CAD) research studies are performed using a single type of Computer Tomography (CT) scanner and therefore, do not take into account the effect of differences in the imaging acquisition scanner parameters. In this paper, we present a study on the effect of the CT parameters on the low-level image features automatically extracted from CT images for lung nodule interpretation. The study is an extension of our previous study where we showed that image features can be used to predict semantic characteristics of lung nodules such as margin, lobulation, spiculation, and texture. Using the Lung Image Data Consortium (LIDC) dataset, we propose to integrate the imaging acquisition parameters with the low-level image features to generate classification models for the nodules' semantic characteristics. Our preliminary results identify seven CT parameters (convolution kernel, reconstruction diameter, exposure, nodule location along the z-axis, distance source to patient, slice thickness, and kVp) as influential in producing classification rules for the LIDC semantic characteristics. Further post-processing analysis, which included running box plots and binning of values, identified four CT parameters: distance source to patient, kVp, nodule location, and rescale intercept. The identification of these parameters will create the premises to normalize the image features across different scanners and, in the long run, generate automatic rules for lung nodules interpretation independently of the CT scanner types.

  15. Fast kilovoltage/megavoltage (kVMV) breathhold cone-beam CT for image-guided radiotherapy of lung cancer

    Science.gov (United States)

    Wertz, Hansjoerg; Stsepankou, Dzmitry; Blessing, Manuel; Rossi, Michael; Knox, Chris; Brown, Kevin; Gros, Uwe; Boda-Heggemann, Judit; Walter, Cornelia; Hesser, Juergen; Lohr, Frank; Wenz, Frederik

    2010-08-01

    Long image acquisition times of 60-120 s for cone-beam CT (CBCT) limit the number of patients with lung cancer who can undergo volume image guidance under breathhold. We developed a low-dose dual-energy kilovoltage-megavoltage-cone-beam CT (kVMV-CBCT) based on a clinical treatment unit reducing imaging time to dose. Single MV-projections, reconstructed MV-CBCT images and images of simultaneous 90° kV- and 90° MV-CBCT (180° kVMV-CBCT) were acquired with different parameters. Image quality and imaging dose were evaluated and compared to kV-imaging. Hardware-based kVMV synchronization resulted in artifact-free projections. A combined 180° kVMV-CBCT scan with a total MV-dose of 5 monitor units was acquired in 15 s and with sufficient image quality. The resolution was 5-6 line pairs cm-1 (Catphan phantom). The combined kVMV-scan dose was equivalent to a kV-radiation scan dose of ~33 mGy. kVMV-CBCT based on a standard linac is promising and can provide ultra-fast online volume image guidance with low imaging dose and sufficient image quality for fast and accurate patient positioning for patients with lung cancer under breathhold.

  16. Imaging in covert ectopic ACTH secretion: a CT pictorial review

    Energy Technology Data Exchange (ETDEWEB)

    Sookur, Paul A.; Sahdev, Anju; Rockall, Andrea G.; Reznek, Rodney H. [St Bartholomew' s Hospital, Department of Academic Radiology, Dominion House, London (United Kingdom); Isidori, Andrea M. [Sapienza University of Rome, Department of Medical Pathophysiology, Rome (Italy); Monson, John P.; Grossman, Ashley B. [St Bartholomew' s Hospital, Department of Endocrinology, London (United Kingdom)

    2009-05-15

    The syndrome of ectopic adrenocorticotrophin secretion (EAS) is rare and is due to excess adrenocorticotrophin (ACTH) production from a nonpituitary tumour. These tumours can be covert, where the tumours are not readily apparent, and very small making them challenging to image. It is clinically and biochemically difficult to distinguish between covert EAS and Cushing's disease. The first-line investigation in locating the source of ACTH production is computed tomography (CT). The aim of this pictorial review is to illustrate the likely covert sites and related imaging findings. We review the CT appearances of tumours resulting in covert EAS and the associated literature. The most common tumours were bronchial carcinoid tumours, which appear as small, well-defined, round or ovoid pulmonary lesions. Rarer causes included thymic carcinoids, gastrointestinal carcinoids and pancreatic neuroendocrine tumours. Awareness of the imaging characteristics will aid identification of the source of ACTH production and allow potentially curative surgical resection. (orig.)

  17. Automatic annotation of radiological observations in liver CT images.

    Science.gov (United States)

    Gimenez, Francisco; Xu, Jiajing; Liu, Yi; Liu, Tiffany; Beaulieu, Christopher; Rubin, Daniel; Napel, Sandy

    2012-01-01

    We aim to predict radiological observations using computationally-derived imaging features extracted from computed tomography (CT) images. We created a dataset of 79 CT images containing liver lesions identified and annotated by a radiologist using a controlled vocabulary of 76 semantic terms. Computationally-derived features were extracted describing intensity, texture, shape, and edge sharpness. Traditional logistic regression was compared to L(1)-regularized logistic regression (LASSO) in order to predict the radiological observations using computational features. The approach was evaluated by leave one out cross-validation. Informative radiological observations such as lesion enhancement, hypervascular attenuation, and homogeneous retention were predicted well by computational features. By exploiting relationships between computational and semantic features, this approach could lead to more accurate and efficient radiology reporting.

  18. FDG PET/CT imaging as a biomarker in lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Meignan, Michel; Itti, Emmanuel [Hopitaux Universitaires Henri Mondor, Paris-Est Creteil University, LYSA Imaging, Department of Nuclear Medicine, Creteil (France); Gallamini, Andrea [Nice University, Research, Innovation and Statistic Department, Antoine Lacassagne Cancer Center, Nice (France); Scientific Research Committee, S. Croce Hospital, Cuneo (Italy); Younes, Anas [Memorial Sloan Kettering Cancer Center, Lymphoma Service, New York, NY (United States)

    2015-04-01

    FDG PET/CT has changed the management of FDG-avid lymphoma and is now recommended as the imaging technique of choice for staging and restaging. The need for tailoring therapy to reduce toxicity in patients with a favourable outcome and for improving treatment in those with high-risk factors requires accurate diagnostic methods and a new prognostic algorithm to identify different risk categories. New drugs are used in relapsed/refractory patients. The role of FDG PET/CT as a biomarker in this context is summarized in this review. New trends in FDG metabolic imaging in lymphoma are addressed including metabolic tumour volume measurement at staging and integrative PET which combines PET data with clinical and molecular markers or other imaging techniques. The quantitative approach for response assessment which is under investigation and is used in large ongoing trials is compared with visual criteria. The place of FDG in the era of targeted therapy is discussed. (orig.)

  19. Fast and automatic ultrasound simulation from CT images.

    Science.gov (United States)

    Cong, Weijian; 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.

  20. Fast and Automatic Ultrasound Simulation from CT Images

    Directory of Open Access Journals (Sweden)

    Weijian Cong

    2013-01-01

    Full Text Available 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.

  1. Hepatic CT Image Query Based on Threshold-based Classification Scheme with Gabor Features

    Institute of Scientific and Technical Information of China (English)

    JIANG Li-jun; LUO Yong-zing; ZHAO Jun; ZHUANG Tian-ge

    2008-01-01

    Hepatic computed tomography (CT) images with Gabor function were analyzed.Then a thresholdbased classification scheme was proposed using Gabor features and proceeded with the retrieval of the hepatic CT images.In our experiments,a batch of hepatic CT images containing several types of CT findings was used and compared with the Zhao's image classification scheme,support vector machines (SVM) scheme and threshold-based scheme.

  2. Nondestructive Evaluation of Hardwood Logs Using Automated Interpretation of CT Images

    Science.gov (United States)

    Daniel L. Schmoldt; Dongping Zhu; Richard W. Conners

    1993-01-01

    Computed tomography (CT) imaging is being used to examine the internal structure of hardwood logs. The following steps are used to automatically interpret CT images: (1) preprocessing to remove unwanted portions of the image, e.g., annual ring structure, (2) image-by-image segmentation to produce relatively homogeneous image areas, (3) volume growing to create volumes...

  3. Validating and improving CT ventilation imaging by correlating with ventilation 4D-PET/CT using {sup 68}Ga-labeled nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kipritidis, John, E-mail: john.kipritidis@sydney.edu.au; Keall, Paul J. [Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Sydney NSW 2006 (Australia); Siva, Shankar [Department of Radiation Oncology, Peter MacCallum Cancer Centre, and Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville VIC 3052 (Australia); Hofman, Michael S.; Callahan, Jason; Hicks, Rodney J. [Centre for Cancer Imaging, Peter MacCallum Cancer Centre and Department of Medicine, University of Melbourne, Melbourne VIC 3002 (Australia)

    2014-01-15

    Purpose: CT ventilation imaging is a novel functional lung imaging modality based on deformable image registration. The authors present the first validation study of CT ventilation using positron emission tomography with{sup 68}Ga-labeled nanoparticles (PET-Galligas). The authors quantify this agreement for different CT ventilation metrics and PET reconstruction parameters. Methods: PET-Galligas ventilation scans were acquired for 12 lung cancer patients using a four-dimensional (4D) PET/CT scanner. CT ventilation images were then produced by applying B-spline deformable image registration between the respiratory correlated phases of the 4D-CT. The authors test four ventilation metrics, two existing and two modified. The two existing metrics model mechanical ventilation (alveolar air-flow) based on Hounsfield unit (HU) change (V{sub HU}) or Jacobian determinant of deformation (V{sub Jac}). The two modified metrics incorporate a voxel-wise tissue-density scaling (ρV{sub HU} and ρV{sub Jac}) and were hypothesized to better model the physiological ventilation. In order to assess the impact of PET image quality, comparisons were performed using both standard and respiratory-gated PET images with the former exhibiting better signal. Different median filtering kernels (σ{sub m} = 0 or 3 mm) were also applied to all images. As in previous studies, similarity metrics included the Spearman correlation coefficient r within the segmented lung volumes, and Dice coefficient d{sub 20} for the (0 − 20)th functional percentile volumes. Results: The best agreement between CT and PET ventilation was obtained comparing standard PET images to the density-scaled HU metric (ρV{sub HU}) with σ{sub m} = 3 mm. This leads to correlation values in the ranges 0.22 ⩽ r ⩽ 0.76 and 0.38 ⩽ d{sub 20} ⩽ 0.68, with r{sup ¯}=0.42±0.16 and d{sup ¯}{sub 20}=0.52±0.09 averaged over the 12 patients. Compared to Jacobian-based metrics, HU-based metrics lead to statistically significant

  4. Multislice CT brain image registration for perfusion studies

    Science.gov (United States)

    Lin, Zhong Min; Pohlman, Scott; Chandra, Shalabh

    2002-04-01

    During the last several years perfusion CT techniques have been developed as an effective technique for clinically evaluating cerebral hemodynamics. Perfusion CT techniques are capable of measurings functional parameters such as tissue perfusion, blood flow, blood volume, and mean transit time and are commonly used to evaluate stroke patients. However, the quality of functional images of the brain frequently suffers from patient head motion. Because the time window for an effective treatment of stroke patient is narrow, a fast motion correction is required. The purpose of the paper is to present a fast and accurate registration technique for motion correction of multi-slice CT and to demonstrate the effects of the registration on perfusion calculation.

  5. Molecular Imaging with Small Animal PET/CT

    DEFF Research Database (Denmark)

    2011-01-01

    in this field of small animal molecular imaging with special emphasis on the targets for tissue characterization in tumor biology such as hypoxia, proliferation and cancer specific over-expression of receptors. The added value of applying CT imaging for anatomical localization and tumor volume measurements...... is also described. In addition, the non-invasive nature of molecular imaging and the targets of these promising new tracers are attractive for other research areas as well, although these fields are much less explored. We present an example of an interesting research field with the application of small...

  6. SU-E-J-209: Verification of 3D Surface Registration Between Stereograms and CT Images

    Energy Technology Data Exchange (ETDEWEB)

    Han, T; Gifford, K [UT MD Anderson Cancer Center, Houston, TX (United States); Smith, B [MD Anderson Cancer Center, Houston, TX (United States); Salehpour, M [M.D. Anderson Cancer Center, Houston, TX (United States)

    2014-06-01

    Purpose: Stereography can provide a visualization of the skin surface for radiation therapy patients. The aim of this study was to verify the registration algorithm in a commercial image analysis software, 3dMDVultus, for the fusion of stereograms and CT images. Methods: CT and stereographic scans were acquired of a head phantom and a deformable phantom. CT images were imported in 3dMDVultus and the surface contours were generated by threshold segmentation. Stereograms were reconstructed in 3dMDVultus. The resulting surfaces were registered with Vultus algorithm and then exported to in-house registration software and compared with four algorithms: rigid, affine, non-rigid iterative closest point (ICP) and b-spline algorithm. RMS (root-mean-square residuals of the surface point distances) error between the registered CT and stereogram surfaces was calculated and analyzed. Results: For the head phantom, the maximum RMS error between registered CT surfaces to stereogram was 6.6 mm for Vultus algorithm, whereas the mean RMS error was 0.7 mm. For the deformable phantom, the maximum RMS error was 16.2 mm for Vultus algorithm, whereas the mean RMS error was 4.4 mm. Non-rigid ICP demonstrated the best registration accuracy, as the mean of RMS errors were both within 1 mm. Conclusion: The accuracy of registration algorithm in 3dMDVultus was verified and exceeded RMS of 2 mm for deformable cases. Non-rigid ICP and b-spline algorithms improve the registration accuracy for both phantoms, especially in deformable one. For those patients whose body habitus deforms during radiation therapy, more advanced nonrigid algorithms need to be used.

  7. Importance of PET/CT for imaging of colorectal cancer; Stellenwert der PET/CT zur Bildgebung des kolorektalen Karzinoms

    Energy Technology Data Exchange (ETDEWEB)

    Meinel, F.G.; Schramm, N.; Graser, A.; Reiser, M.F.; Rist, C. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Grosshadern, Institut fuer Klinische Radiologie, Muenchen (Germany); Haug, A.R. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Grosshadern, Klinik und Poliklinik fuer Nuklearmedizin, Muenchen (Germany)

    2012-06-15

    Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) has emerged as a very useful imaging modality in the management of colorectal carcinoma. Data from the literature regarding the role of PET/CT in the initial diagnosis, staging, radiotherapy planning, response monitoring and surveillance of colorectal carcinoma is presented. Future directions and economic aspects are discussed. Computed tomography (CT), magnetic resonance imaging (MRI) and FDG-PET for colorectal cancer and endorectal ultrasound for rectal cancer. Combined FDG-PET/CT. While other imaging modalities allow superior visualization of the extent and invasion depth of the primary tumor, PET/CT is most sensitive for the detection of distant metastases of colorectal cancer. We recommend a targeted use of PET/CT in cases of unclear M staging, prior to metastasectomy and in suspected cases of residual or recurrent colorectal carcinoma with equivocal conventional imaging. The role of PET/CT in radiotherapy planning and response monitoring needs to be determined. Currently there is no evidence to support the routine use of PET/CT for colorectal screening, staging or surveillance. To optimally exploit the synergy between morphologic and functional information, FDG-PET should generally be performed as an integrated FDG-PET/CT with a contrast-enhanced CT component in colorectal carcinoma. (orig.) [German] Die Fluordesoxyglukose-Positronenemissionstomographie/Computertomographie (FDG-PET/CT) hat in den letzten Jahren zunehmende Bedeutung zur Bildgebung des kolorektalen Karzinoms erlangt. In diesem Beitrag stellen wir den Stand der Literatur zur Rolle der PET/CT bei Screening, Staging, Bestrahlungsplanung, Beurteilung eines Therapieansprechens und Nachsorge des kolorektalen Karzinoms dar. Zudem wird auf gesundheitsoekonomische Aspekte und zukuenftige Entwicklungen eingegangen. CT, MRT, FDG-PET, beim Rektumkarzinom zusaetzlich endorektaler Ultraschall. Kombinierte FDG-PET/CT. Waehrend

  8. SPECT-CT Hybrid cardiac imaging synchronized to Ecg for the mouse after myocardium infarction; Imagerie cardiaque hybride TEMP-TDM synchronisee a l'ECG chez la souris apres infarctus du myocarde

    Energy Technology Data Exchange (ETDEWEB)

    Choquet, P.; Goetz, C.; Aubertin, G.; Hubele, F. [HUS Strasbourg, Service de biophysique et medecine nucleaire, 67 (France); El-Fertak, L.; Monassier, L. [Laboratoire de pharmacologie cardiovasculaire, 67 - Strasbourg (France)

    2010-07-01

    The preclinical SPECT-CT imaging synchronized to electrocardiogram among mice allows to acquire isotropic morphological and functional data, data of high spatial and temporal resolutions with relatively short acquisition times. (N.C.)

  9. Automatic cable artifact removal for cardiac C-arm CT imaging

    Science.gov (United States)

    Haase, C.; Schäfer, D.; Kim, M.; Chen, S. J.; Carroll, J.; Eshuis, P.; Dössel, O.; Grass, M.

    2014-03-01

    Cardiac C-arm computed tomography (CT) imaging using interventional C-arm systems can be applied in various areas of interventional cardiology ranging from structural heart disease and electrophysiology interventions to valve procedures in hybrid operating rooms. In contrast to conventional CT systems, the reconstruction field of view (FOV) of C-arm systems is limited to a region of interest in cone-beam (along the patient axis) and fan-beam (in the transaxial plane) direction. Hence, highly X-ray opaque objects (e.g. cables from the interventional setup) outside the reconstruction field of view, yield streak artifacts in the reconstruction volume. To decrease the impact of these streaks a cable tracking approach on the 2D projection sequences with subsequent interpolation is applied. The proposed approach uses the fact that the projected position of objects outside the reconstruction volume depends strongly on the projection perspective. By tracking candidate points over multiple projections only objects outside the reconstruction volume are segmented in the projections. The method is quantitatively evaluated based on 30 simulated CT data sets. The 3D root mean square deviation to a reference image could be reduced for all cases by an average of 50 % (min 16 %, max 76 %). Image quality improvement is shown for clinical whole heart data sets acquired on an interventional C-arm system.

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

    Science.gov (United States)

    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

  11. Automated determination of spinal centerline in CT and MR images

    Science.gov (United States)

    Štern, Darko; Vrtovec, Tomaž; Pernuš, Franjo; Likar, Boštjan

    2009-02-01

    The spinal curvature is one of the most important parameters for the evaluation of spinal deformities. The spinal centerline, represented by the curve that passes through the centers of the vertebral bodies in three-dimensions (3D), allows valid quantitative measurements of the spinal curvature at any location along the spine. We propose a novel automated method for the determination of the spinal centerline in 3D spine images. Our method exploits the anatomical property that the vertebral body walls are cylindrically-shaped and therefore the lines normal to the edges of the vertebral body walls most often intersect in the middle of the vertebral bodies, i.e. at the location of spinal centerline. These points of intersection are first obtained by a novel algorithm that performs a selective search in the directions normal to the edges of the structures and then connected with a parametric curve that represents the spinal centerline in 3D. As the method is based on anatomical properties of the 3D spine anatomy, it is modality-independent, i.e. applicable to images obtained by computed tomography (CT) and magnetic resonance (MR). The proposed method was evaluated on six CT and four MR images (T1- and T2-weighted) of normal spines and on one scoliotic CT spine image. The qualitative and quantitative results for the normal spines show that the spinal centerline can be successfully determined in both CT and MR spine images, while the results for the scoliotic spine indicate that the method may also be used to evaluate pathological curvatures.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  14. CT scan range estimation using multiple body parts detection: let PACS learn the CT image content.

    Science.gov (United States)

    Wang, Chunliang; Lundström, Claes

    2016-02-01

    The aim of this study was to develop an efficient CT scan range estimation method that is based on the analysis of image data itself instead of metadata analysis. This makes it possible to quantitatively compare the scan range of two studies. In our study, 3D stacks are first projected to 2D coronal images via a ray casting-like process. Trained 2D body part classifiers are then used to recognize different body parts in the projected image. The detected candidate regions go into a structure grouping process to eliminate false-positive detections. Finally, the scale and position of the patient relative to the projected figure are estimated based on the detected body parts via a structural voting. The start and end lines of the CT scan are projected to a standard human figure. The position readout is normalized so that the bottom of the feet represents 0.0, and the top of the head is 1.0. Classifiers for 18 body parts were trained using 184 CT scans. The final application was tested on 136 randomly selected heterogeneous CT scans. Ground truth was generated by asking two human observers to mark the start and end positions of each scan on the standard human figure. When compared with the human observers, the mean absolute error of the proposed method is 1.2% (max: 3.5%) and 1.6% (max: 5.4%) for the start and end positions, respectively. We proposed a scan range estimation method using multiple body parts detection and relative structure position analysis. In our preliminary tests, the proposed method delivered promising results.

  15. Paired inspiratory/expiratory volumetric CT and deformable image registration for quantitative and qualitative evaluation of airflow limitation in smokers with or without copd.

    Science.gov (United States)

    Nishio, Mizuho; Matsumoto, Sumiaki; Tsubakimoto, Maho; Nishii, Tatsuya; Koyama, Hisanobu; Ohno, Yoshiharu; Sugimura, Kazuro

    2015-03-01

    To evaluate paired inspiratory/expiratory computed tomography (CT; iCT/eCT) and deformable image registration for quantitative and qualitative assessment of airflow limitation in smokers. Paired iCT/eCT images acquired from 35 smokers (30 men and 5 women) were coregistered and subtraction images (air trapping CT images [aCT]) generated. To evaluate emphysema quantitatively, the percentage of low-attenuation volume (LAV%) on iCT was calculated at -950 HU, as were mean and kurtosis on aCT for quantitative assessment of air trapping. Parametric response maps of emphysema (PRMe) and of functional small airways disease (PRMs) were also obtained. For qualitative evaluation of emphysema, low-attenuation areas on iCT were scored by consensus of two radiologists using Goddard classification. To assess air trapping qualitatively, the degree of air trapping on aCT was scored. For each quantitative and qualitative index, the Spearman rank correlation coefficient for forced expiratory flow in 1 second was calculated, and differences in correlation coefficients were statistically tested. The correlation coefficients for the indices were as follows: mean on aCT, 0.800; kurtosis on aCT, -0.726; LAV%, -0.472; PRMe, -0.570; PRMs, -0.565; addition of PRMe and PRMs, -0.653; emphysema score, -0.502; air trapping score, -0.793. The indices showing significant differences were as follows: mean on aCT and addition of PRMe and PRMs (P = 1.43 × 10(-8)); air trapping score and emphysema score (P = .0169). Air trapping images yielded more accurate quantitative and qualitative evaluation of airflow limitation than did LAV%, PRMe, PRMs, and Goddard classification. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

  16. Pitfalls and Limitations of PET/CT in Brain Imaging.

    Science.gov (United States)

    Salmon, Eric; Bernard Ir, Claire; Hustinx, Roland

    2015-11-01

    Neurologic applications were at the forefront of PET imaging when the technique was developed in the mid-1970s. Although oncologic indications have become prominent in terms of number of studies performed worldwide, neurology remains a major field in which functional imaging provides unique information, both for clinical and research purposes. The evaluation of glucose metabolism using FDG remains the most frequent exploration, but in recent years, alternative radiotracers have been developed, including fluorinated amino acid analogues for primary brain tumor imaging and fluorinated compounds for assessing the amyloid deposits in patients with suspected Alzheimer disease. As the brain is enclosed in the skull, which presents fixed landmarks, it is relatively easy to coregister images obtained with various cross-sectional imaging methods, either functional or anatomical, with a relatively high accuracy and robustness. Nevertheless, PET in neurology has fully benefited from the advent of hybrid imaging. Attenuation and scatter correction is now much faster and equally accurate, using CT as compared with the traditional transmission scan using an external radioactive source. The perfect coregistration with the CT data, which is now systematically performed, also provides its own set of valuable information, for instance regarding cerebral atrophy. However, hybrid imaging in neurology comes with pitfalls and limitations, in addition to those that are well known, for example, blood glucose levels or psychotropic drugs that greatly affect the physiological FDG uptake. Movements of the patient's head, either during the PET acquisition or between the PET and the CT acquisitions will generate artifacts that may be very subtle yet lead to erroneous interpretation of the study. Similarly, quantitative analysis, such as voxel-based analyses, may prove very helpful in improving the diagnostic accuracy and the reproducibility of the reading, but a wide variety of artifacts may

  17. Advanced large airway CT imaging in children: evolution from axial to 4-D assessment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Edward Y. [Boston Children' s Hospital and Harvard Medical School, Departments of Radiology and Medicine, Boston, MA (United States); Zucker, Evan J. [Tufts Medical Center, Department of Radiology, Floating Hospital for Children, Boston, MA (United States); Restrepo, Ricardo [Miami Children' s Hospital, Department of Radiology, Miami, FL (United States); Daltro, Pedro [Clinica de DiagnOstico Por Imagem, Rio de Janeiro (Brazil); Boiselle, Phillip M. [Beth Israel Deaconess Medical Center and Harvard Medical School, Department of Radiology, Boston, MA (United States)

    2013-03-15

    Continuing advances in multidetector computed tomography (MDCT) technology are revolutionizing the non-invasive evaluation of congenital and acquired large airway disorders in children. For example, the faster scanning time and increased anatomical coverage that are afforded by MDCT are especially beneficial to children. MDCT also provides high-quality multiplanar 2-dimensional (2-D), internal and external volume-rendering 3-dimensional (3-D), and dynamic 4-dimensional (4-D) imaging. These advances have enabled CT to become the primary non-invasive imaging modality of choice for the diagnosis, treatment planning, and follow-up evaluation of various large airway disorders in infants and children. It is thus essential for radiologists to be familiar with safe and effective techniques for performing MDCT and to be able to recognize the characteristic imaging appearances of large airway disorders affecting children. (orig.)

  18. SU-D-BRB-01: 4D-CT Lung Ventilation Images Vary with 4D-CT Sorting Techniques.

    Science.gov (United States)

    Yamamoto, T; Kabus, S; Lorenz, C; Johnston, E; Maxim, P; Loo, B; Keall, P

    2012-06-01

    4D-CT ventilation imaging is a novel promising technique for lung functional imaging and has potential as a biomarker for radiation pneumonitis, but has not been validated in human subjects. The current 4D- CT technique with phase-based sorting results in artifacts at an alarmingly high frequency (90%), which may introduce variations into ventilation calculations. The purpose of this study was to quantify the variability of 4D- CT ventilation imaging to 4D-CT sorting techniques. Two 4D-CT images were generated from the same data set by: (1) phase-based; (2) anatomic similarity- and abdominal displacement-based sorting for five patients. Two ventilation image sets (V_phase and V_anat) were then calculated by deformable image registration of peak-exhale and peak-inhale4D-CT images and quantification of regional volume change based on Hounsfield unit change. The variability of 4D-CT ventilation imaging wasquantified using the voxel-based Spearman rank correlation coefficients and Dice similarity coefficients (DSC) for the spatial overlap of segmented low- functional lung regions. The relationship between the abdominal motionrange variation and ventilation variation was also assessed using linearregression. Furthermore, the correlations between V_phase or V_anat and SPECT ventilation images (assumed ground-truth) were compared. In general, displacement- and anatomic similarity-based sorting reduced 4D- CT artifacts compared to phase-based sorting. The voxel-based correlationsbetween V_phase and V_anat were only moderate (range, 0.57-0.77). The DSCs for the low-functional lung regions were moderate to substantial (0.58-0.70). The relationship between the motion range variation and ventilation variation was strong on average (R2=0.79±0.25), suggesting that ventilation variations are related to 4D-CT artifacts. Vanat was found to improve correlations with SPECT ventilation images compared to V_phase. 4D-CT ventilation images vary markedly with 4D-CT sorting techniques. 4

  19. Improved compressed sensing-based cone-beam CT reconstruction using adaptive prior image constraints

    Science.gov (United States)

    Lee, Ho; Xing, Lei; Davidi, Ran; Li, Ruijiang; Qian, Jianguo; Lee, Rena

    2012-04-01

    Volumetric cone-beam CT (CBCT) images are acquired repeatedly during a course of radiation therapy and a natural question to ask is whether CBCT images obtained earlier in the process can be utilized as prior knowledge to reduce patient imaging dose in subsequent scans. The purpose of this work is to develop an adaptive prior image constrained compressed sensing (APICCS) method to solve this problem. Reconstructed images using full projections are taken on the first day of radiation therapy treatment and are used as prior images. The subsequent scans are acquired using a protocol of sparse projections. In the proposed APICCS algorithm, the prior images are utilized as an initial guess and are incorporated into the objective function in the compressed sensing (CS)-based iterative reconstruction process. Furthermore, the prior information is employed to detect any possible mismatched regions between the prior and current images for improved reconstruction. For this purpose, the prior images and the reconstructed images are classified into three anatomical regions: air, soft tissue and bone. Mismatched regions are identified by local differences of the corresponding groups in the two classified sets of images. A distance transformation is then introduced to convert the information into an adaptive voxel-dependent relaxation map. In constructing the relaxation map, the matched regions (unchanged anatomy) between the prior and current images are assigned with smaller weight values, which are translated into less influence on the CS iterative reconstruction process. On the other hand, the mismatched regions (changed anatomy) are associated with larger values and the regions are updated more by the new projection data, thus avoiding any possible adverse effects of prior images. The APICCS approach was systematically assessed by using patient data acquired under standard and low-dose protocols for qualitative and quantitative comparisons. The APICCS method provides an

  20. CT perfusion image processing: analysis of liver tumors

    OpenAIRE

    D’Antò, Michela

    2013-01-01

    Perfusion CT imaging of the liver has potential to improve evaluation of tumour angiogenesis. Quantitative parameters can be obtained applying mathematical models to Time Attenuation Curve (TAC). However, there are still some difficulties for an accurate quantification of perfusion parameters due, for example, to algorithms employed, to mathematical model, to patient’s weight and cardiac output and to the acquisition system. In this thesis, new parameters and alternative methodologies ab...

  1. Imaging of cochlear implant electrode array with flat-detector CT and conventional multislice CT: comparison of image quality and radiation dose.

    Science.gov (United States)

    Struffert, Tobias; Hertel, Victoria; Kyriakou, Yannis; Krause, Jens; Engelhorn, Tobias; Schick, Bernhard; Iro, Heinrich; Hornung, Joachim; Doerfler, Arnd

    2010-04-01

    Cochlear implantation assessment is possible using commercially available standard flat-detector computed tomography (FD-CT) protocols. Image quality is superior to multislice CT (MSCT). The radiation dose of FD-CT is lower in comparison with MSCT standard protocols and may therefore overcome the limitations of MSCT in the evaluation of cochlear implants. FD-CT offers higher spatial resolution than MSCT. Our objective was to compare the image quality of FD-CT to conventional MSCT in the visualization of a cochlear implant electrode array with respect to radiation exposure. An isolated temporal bone specimen was scanned using a commercially available FD-CT system and a 4 and 64 row MSCT scanner. Different scanning protocols were used. Image quality was assessed by four independent readers using a scoring system with different criteria describing delineation of the cochlea and the electrode array, image noise and spatial resolution. Radiation dose was measured using the CT dose index (CTDI) and a 16 cm acrylic phantom. Image quality was rated superior for FD-CT for all criteria by all readers. Single electrode contacts were only visible in FD-CT and assessment of implant position was improved by FD-CT. The radiation dose of FD-CT was half that of MSCT standard protocols.

  2. Prenatally acquired hypoxic encephalopathy (prenatal CTG and postpartal CT-changes)

    Energy Technology Data Exchange (ETDEWEB)

    Fricker, H.S.; Sauter, M.; Buchs, B.

    A para III was found to have a constantly silent CTG. In weo fetas blood analyses the pH was normal. During the first few hours post partum the infant had rapidly increasing neurologic disturbances with violent convulsions and coma. As early as on the first day of life the computer tomogram showed extensive, later persistent hypodense zones corresponding to severe asphyxial cerebral necrosis. Based an the course of CT changes it has to be assumed that the hypoxic crisis occurred some days prior to the onset of labor. Pathologic changes in the umbilical cord indicated that the cause could have been a transitory occlusion in utero. The computer tomogram enables cerebral insults to be dated more accurately. If prenatal hypoxia occurs repeatedly new methods of prevention must be sought.

  3. Optical-CT imaging of complex 3D dose distributions

    Science.gov (United States)

    Oldham, Mark; Kim, Leonard; Hugo, Geoffrey

    2005-04-01

    The limitations of conventional dosimeters restrict the comprehensiveness of verification that can be performed for advanced radiation treatments presenting an immediate and substantial problem for clinics attempting to implement these techniques. In essence, the rapid advances in the technology of radiation delivery have not been paralleled by corresponding advances in the ability to verify these treatments. Optical-CT gel-dosimetry is a relatively new technique with potential to address this imbalance by providing high resolution 3D dose maps in polymer and radiochromic gel dosimeters. We have constructed a 1st generation optical-CT scanner capable of high resolution 3D dosimetry and applied it to a number of simple and increasingly complex dose distributions including intensity-modulated-radiation-therapy (IMRT). Prior to application to IMRT, the robustness of optical-CT gel dosimetry was investigated on geometry and variable attenuation phantoms. Physical techniques and image processing methods were developed to minimize deleterious effects of refraction, reflection, and scattered laser light. Here we present results of investigations into achieving accurate high-resolution 3D dosimetry with optical-CT, and show clinical examples of 3D IMRT dosimetry verification. In conclusion, optical-CT gel dosimetry can provide high resolution 3D dose maps that greatly facilitate comprehensive verification of complex 3D radiation treatments. Good agreement was observed at high dose levels (>50%) between planned and measured dose distributions. Some systematic discrepancies were observed however (rms discrepancy 3% at high dose levels) indicating further work is required to eliminate confounding factors presently compromising the accuracy of optical-CT 3D gel-dosimetry.

  4. Quantitative imaging of excised osteoarthritic cartilage using spectral CT

    Energy Technology Data Exchange (ETDEWEB)

    Rajendran, Kishore; Bateman, Christopher J.; Younis, Raja Aamir; De Ruiter, Niels J.A.; Ramyar, Mohsen; Anderson, Nigel G. [University of Otago - Christchurch, Department of Radiology, Christchurch (New Zealand); Loebker, Caroline [University of Otago, Christchurch Regenerative Medicine and Tissue Engineering Group, Department of Orthopaedic Surgery and Musculoskeletal Medicine, Christchurch (New Zealand); University of Twente, Department of Developmental BioEngineering, Enschede (Netherlands); Schon, Benjamin S.; Hooper, Gary J.; Woodfield, Tim B.F. [University of Otago, Christchurch Regenerative Medicine and Tissue Engineering Group, Department of Orthopaedic Surgery and Musculoskeletal Medicine, Christchurch (New Zealand); Chernoglazov, Alex I. [University of Canterbury, Human Interface Technology Laboratory New Zealand, Christchurch (New Zealand); Butler, Anthony P.H. [University of Otago - Christchurch, Department of Radiology, Christchurch (New Zealand); European Organisation for Nuclear Research (CERN), Geneva (Switzerland); MARS Bioimaging, Christchurch (New Zealand)

    2017-01-15

    To quantify iodine uptake in articular cartilage as a marker of glycosaminoglycan (GAG) content using multi-energy spectral CT. We incubated a 25-mm strip of excised osteoarthritic human tibial plateau in 50 % ionic iodine contrast and imaged it using a small-animal spectral scanner with a cadmium telluride photon-processing detector to quantify the iodine through the thickness of the articular cartilage. We imaged both spectroscopic phantoms and osteoarthritic tibial plateau samples. The iodine distribution as an inverse marker of GAG content was presented in the form of 2D and 3D images after applying a basis material decomposition technique to separate iodine in cartilage from bone. We compared this result with a histological section stained for GAG. The iodine in cartilage could be distinguished from subchondral bone and quantified using multi-energy CT. The articular cartilage showed variation in iodine concentration throughout its thickness which appeared to be inversely related to GAG distribution observed in histological sections. Multi-energy CT can quantify ionic iodine contrast (as a marker of GAG content) within articular cartilage and distinguish it from bone by exploiting the energy-specific attenuation profiles of the associated materials. (orig.)

  5. Kinematic CT and MR imaging of the patellofemoral joint

    Energy Technology Data Exchange (ETDEWEB)

    Muhle, C.; Brossmann, J.; Heller, M. [Klinik fuer Radiologische Diagnostik, Christian-Albrechts-Universitaet, Kiel (Germany)

    1999-04-01

    Anterior knee pain is a frequently encountered orthopedic symptom and is often associated with patellofemoral malalignment, which may cause chondromalacia of the patella. The difficulty in determining the patellar position between 0 and 30 of knee flexion with a conventional axial radiographic examination is well known. The introduction of computed tomography (CT) and magnetic resonance (MR) imaging for the diagnosis of knee joint abnormalities has enabled assessment of the patellar position in this critical range. More recently, emphasis has been placed on dynamic visualization of patellar motion to detect an abnormal tracking pattern. The important influence of the quadriceps muscle on the patellar tracking pattern is well known and has been examined during active knee extension by the use of ultrafast CT, and motion-triggered and ultrafast MR imaging. This article provides an overview of the current status of kinematic CT and MR imaging in the diagnosis of patellofemoral alignment, its clinical implications, and future directions. (orig.) With 13 figs., 5 tabs., 47 refs.

  6. Semiautomatic segmentation of liver metastases on volumetric CT images

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Jiayong [Department of Biomedical Engineering, Shanghai University of Medicine & Health Sciences, 101 Yingkou Road, Yang Pu District, Shanghai 200093 (China); Schwartz, Lawrence H.; Zhao, Binsheng, E-mail: bz2166@cumc.columbia.edu [Department of Radiology, Columbia University Medical Center, 630 West 168th Street, New York, New York 10032 (United States)

    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

  7. Radiation dose reduction in CT of the brain: can advanced noise filtering compensate for loss of image quality?

    Energy Technology Data Exchange (ETDEWEB)

    Siemund, Roger; Loeve, A.; Westen, D. van; Stenberg, L.; Petersen, C. (Dept. of Radiology, Lund Univ., Lund (Sweden); Center for Medical Imaging and Physiology, Skaane Univ. Hospital, Lund (Sweden)), email: roger.siemund@med.lu.se; Bjoerkman-Burtscher, I. M. (Dept. of Radiology, Lund Univ., Lund (Sweden); Center for Medical Imaging and Physiology, Skaane Univ. Hospital, Lund (Sweden); Lund Univ. Bioimaging Center, Lund (Sweden))

    2012-05-15

    Background: Computed tomography (CT) of the brain is performed with high local doses due to high demands on low contrast resolution. Advanced algorithms for noise reduction might be able to preserve critical image information when reducing radiation dose. Purpose: To evaluate the effect of advanced noise filtering on image quality in brain CT acquired with reduced radiation dose. Material and Methods: Thirty patients referred for non-enhanced CT of the brain were examined with two helical protocols: normal dose (ND, CTDIvol 57 mGy) and low dose (LD, CTDIvol 40 mGy) implying a 30% radiation dose reduction. Images from the LD examinations were also post processed with a noise reduction software with non-linear filters (SharpView CT), creating filtered low dose images (FLD) for each patient. The three image stacks for each patient were presented side by side in randomized order. Five radiologists, blinded for dose level and filtering, ranked these three axial image stacks (ND, LD, FLD) as best to poorest (1 to 3) regarding three image quality criteria. Measurements of mean Hounsfield units (HU) and standard deviation (SD) of the HU were calculated for large region of interest in the centrum semiovale as a measure for noise. Results: Ranking results in pooled data showed that the advanced noise filtering significantly improved the image quality in FLD as compared to LD images for all tested criteria. No significant differences in image quality were found between ND examinations and FLD. However, there was a notable inter-reader spread of the ranking. SD values were 15% higher for LD as compared to ND and FLD. Conclusion: The advanced noise filtering clearly improves image quality of CT examinations of the brain. This effect can be used to significantly lower radiation dose.

  8. Classification of images acquired with colposcopy using artificial neural networks.

    Science.gov (United States)

    Simões, Priscyla W; Izumi, Narjara B; Casagrande, Ramon S; Venson, Ramon; Veronezi, Carlos D; Moretti, Gustavo P; da Rocha, Edroaldo L; Cechinel, Cristian; Ceretta, Luciane B; Comunello, Eros; Martins, Paulo J; Casagrande, Rogério A; Snoeyer, Maria L; Manenti, Sandra A

    2014-01-01

    To explore the advantages of using artificial neural networks (ANNs) to recognize patterns in colposcopy to classify images in colposcopy. Transversal, descriptive, and analytical study of a quantitative approach with an emphasis on diagnosis. The training test e validation set was composed of images collected from patients who underwent colposcopy. These images were provided by a gynecology clinic located in the city of Criciúma (Brazil). The image database (n = 170) was divided; 48 images were used for the training process, 58 images were used for the tests, and 64 images were used for the validation. A hybrid neural network based on Kohonen self-organizing maps and multilayer perceptron (MLP) networks was used. After 126 cycles, the validation was performed. The best results reached an accuracy of 72.15%, a sensibility of 69.78%, and a specificity of 68%. Although the preliminary results still exhibit an average efficiency, the present approach is an innovative and promising technique that should be deeply explored in the context of the present study.

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

    Science.gov (United States)

    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.

  10. CT and MR Image Fusion Scheme in Nonsubsampled Contourlet Transform Domain

    OpenAIRE

    Ganasala, Padma; Kumar, Vinod

    2014-01-01

    Fusion of CT and MR images allows simultaneous visualization of details of bony anatomy provided by CT image and details of soft tissue anatomy provided by MR image. This helps the radiologist for the precise diagnosis of disease and for more effective interventional treatment procedures. This paper aims at designing an effective CT and MR image fusion method. In the proposed method, first source images are decomposed by using nonsubsampled contourlet transform (NSCT) which is a shift-invaria...

  11. MR imaging compared with CT, angiography, and myelography supplemented with CT in the diagnosis of spinal tumors

    Energy Technology Data Exchange (ETDEWEB)

    Hasuo, Kanehiro; Uchino, Akira; Matsumoto, Shunichi; Fujii, Kiyotaka; Fukui, Masashi; Masuda, Kouji (Kyushu Univ., Fukuoka (Japan). Faculty of Medicine)

    To clarify the significance of MR imaging and the present status of CT, angiography, and myelography supplemented by CT (M-CTM), the radiological findings of 50 spinal tumors were reviewed and analyzed. MR imaging was most effective for visualizing morphological features such as the margins and/or inner structures of the tumors. CT was also effective for imaging 'dumbbell' neurinomas and extradural tumors. Angiography was necessary in one hemangioblastoma and in cervical extradural tumors. M-CTM visualized the morphology of intradural extramedullary tumors and extradural tumors, but provided no new information in most of these cases. It was concluded that when using MR the indications for CT, angiography, and M-CTM are limited and that CT or angiography should be performed only in selected cases. M-CTM appeared to be unnecessary. (author).

  12. Building Extraction from DSM Acquired by Airborne 3D Image

    Institute of Scientific and Technical Information of China (English)

    YOU Hongjian; LI Shukai

    2003-01-01

    Segmentation and edge regulation are studied deeply to extract buildings from DSM data produced in this paper. Building segmentation is the first step to extract buildings, and a new segmentation method-adaptive iterative segmentation considering ratio mean square-is proposed to extract the contour of buildings effectively. A sub-image (such as 50× 50 pixels )of the image is processed in sequence,the average gray level and its ratio mean square are calculated first, then threshold of the sub-image is selected by using iterative threshold segmentation. The current pixel is segmented according to the threshold, the aver-age gray level and the ratio mean square of the sub-image. The edge points of the building are grouped according to the azimuth of neighbor points, and then the optimal azimuth of the points that belong to the same group can be calculated by using line interpolation.

  13. Elastic registration of multiphase CT images of liver

    Science.gov (United States)

    Heldmann, Stefan; Zidowitz, Stephan

    2009-02-01

    In this work we present a novel approach for elastic image registration of multi-phase contrast enhanced CT images of liver. A problem in registration of multiphase CT is that the images contain similar but complementary structures. In our application each image shows a different part of the vessel system, e.g., portal/hepatic venous/arterial, or biliary vessels. Portal, arterial and biliary vessels run in parallel and abut on each other forming the so called portal triad, while hepatic veins run independent. Naive registration will tend to align complementary vessel. Our new approach is based on minimizing a cost function consisting of a distance measure and a regularizer. For the distance we use the recently proposed normalized gradient field measure that focuses on the alignment of edges. For the regularizer we use the linear elastic potential. The key feature of our approach is an additional penalty term using segmentations of the different vessel systems in the images to avoid overlaps of complementary structures. We successfully demonstrate our new method by real data examples.

  14. Coronary imaging techniques with emphasis on CT and MRI

    Energy Technology Data Exchange (ETDEWEB)

    Lederlin, Mathieu; Latrabe, Valerie; Corneloup, Olivier; Cochet, Hubert; Montaudon, Michel; Laurent, Francois [Hopital Cardiologique, CHU Bordeaux, Thoracic and Cardiovascular Imaging Department, Pessac (France); Thambo, Jean-Benoit [Hopital Cardiologique, CHU Bordeaux, Pediatric and Adult Congenital Heart Disease Unit, Pessac (France)

    2011-12-15

    Coronary artery imaging in children is challenging, with high demands both on temporal and spatial resolution due to high heart rates and smaller anatomy. Although invasive conventional coronary angiography remains the benchmark technique, over the past 10 years, CT and MRI have emerged in the field of coronary imaging. The choice of hardware is important. For CT, the minimum requirement is a 64-channel scanner. The temporal resolution of the scanner is most important for optimising image quality and minimising radiation dose. Manufacturers have developed several modes of electrocardiographic (ECG) triggering to facilitate dose reduction. Recent technical advances have opened new possibilities in MRI coronary imaging. As a non-ionising radiation technique, MRI is of great interest in paediatric imaging. It is currently recommended in centres with appropriate expertise for the screening of patients with suspected congenital coronary anomalies. However, MRI is still not feasible in infants. This review describes and discusses the technical requirements and the pros and cons of all three techniques. (orig.)

  15. Classification of CT brain images based on deep learning networks.

    Science.gov (United States)

    Gao, Xiaohong W; Hui, Rui; Tian, Zengmin

    2017-01-01

    While computerised tomography (CT) may have been the first imaging tool to study human brain, it has not yet been implemented into clinical decision making process for diagnosis of Alzheimer's disease (AD). On the other hand, with the nature of being prevalent, inexpensive and non-invasive, CT does present diagnostic features of AD to a great extent. This study explores the significance and impact on the application of the burgeoning deep learning techniques to the task of classification of CT brain images, in particular utilising convolutional neural network (CNN), aiming at providing supplementary information for the early diagnosis of Alzheimer's disease. Towards this end, three categories of CT images (N = 285) are clustered into three groups, which are AD, lesion (e.g. tumour) and normal ageing. In addition, considering the characteristics of this collection with larger thickness along the direction of depth (z) (~3-5 mm), an advanced CNN architecture is established integrating both 2D and 3D CNN networks. The fusion of the two CNN networks is subsequently coordinated based on the average of Softmax scores obtained from both networks consolidating 2D images along spatial axial directions and 3D segmented blocks respectively. As a result, the classification accuracy rates rendered by this elaborated CNN architecture are 85.2%, 80% and 95.3% for classes of AD, lesion and normal respectively with an average of 87.6%. Additionally, this improved CNN network appears to outperform the others when in comparison with 2D version only of CNN network as well as a number of state of the art hand-crafted approaches. As a result, these approaches deliver accuracy rates in percentage of 86.3, 85.6 ± 1.10, 86.3 ± 1.04, 85.2 ± 1.60, 83.1 ± 0.35 for 2D CNN, 2D SIFT, 2D KAZE, 3D SIFT and 3D KAZE respectively. The two major contributions of the paper constitute a new 3-D approach while applying deep learning technique to extract signature information

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

    Science.gov (United States)

    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.

  17. IMAGE RECONSTRUCTION AND OBJECT CLASSIFICATION IN CT IMAGING SYSTEM

    Institute of Scientific and Technical Information of China (English)

    张晓明; 蒋大真; 等

    1995-01-01

    By obtaining a feasible filter function,reconstructed images can be got with linear interpolation and filtered backoprojection techniques.Considering the gray and spatial correlation neighbour informations of each pixel,a new supervised classification method is put forward for the reconstructed images,and an experiment with noise image is done,the result shows that the method is feasible and accurate compared with ideal phantoms.

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

    Science.gov (United States)

    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.

  19. Fundamentals of PET and PET/CT imaging.

    Science.gov (United States)

    Basu, Sandip; Kwee, Thomas C; Surti, Suleman; Akin, Esma A; Yoo, Don; Alavi, Abass

    2011-06-01

    In this review, the fundamental principles of fluorodeoxyglucose (FDG) positron emission tomography (PET) and FDG PET/computed tomography (CT) imaging have been described. The basic physics of PET instrumentation, radiotracer chemistry, and the artifacts, as well as normal physiological or benign pathological variants, have been described and presented to the readers in a lucid manner to enable them an easy grasp of the fundamentals of the subject. Finally, we have outlined the current developments in quantitative PET imaging, including dual time point and delayed PET imaging, time-of-flight technology in PET imaging and partial volume correction, and global disease assessment with their potential of being incorporated into the assessment of benign and malignant disorders.

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

    Science.gov (United States)

    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.

  1. Dynamic CT perfusion image data compression for efficient parallel processing.

    Science.gov (United States)

    Barros, Renan Sales; Olabarriaga, Silvia Delgado; Borst, Jordi; van Walderveen, Marianne A A; Posthuma, Jorrit S; Streekstra, Geert J; van Herk, Marcel; Majoie, Charles B L M; Marquering, Henk A

    2016-03-01

    The increasing size of medical imaging data, in particular time series such as CT perfusion (CTP), requires new and fast approaches to deliver timely results for acute care. Cloud architectures based on graphics processing units (GPUs) can provide the processing capacity required for delivering fast results. However, the size of CTP datasets makes transfers to cloud infrastructures time-consuming and therefore not suitable in acute situations. To reduce this transfer time, this work proposes a fast and lossless compression algorithm for CTP data. The algorithm exploits redundancies in the temporal dimension and keeps random read-only access to the image elements directly from the compressed data on the GPU. To the best of our knowledge, this is the first work to present a GPU-ready method for medical image compression with random access to the image elements from the compressed data.

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

    Science.gov (United States)

    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.

  3. Rendering-based video-CT registration with physical constraints for image-guided endoscopic sinus surgery

    Science.gov (United States)

    Otake, Y.; Leonard, S.; Reiter, A.; Rajan, P.; Siewerdsen, J. H.; Ishii, M.; Taylor, R. H.; Hager, G. D.

    2015-03-01

    We present a system for registering the coordinate frame of an endoscope to pre- or intra- operatively acquired CT data based on optimizing the similarity metric between an endoscopic image and an image predicted via rendering of CT. Our method is robust and semi-automatic because it takes account of physical constraints, specifically, collisions between the endoscope and the anatomy, to initialize and constrain the search. The proposed optimization method is based on a stochastic optimization algorithm that evaluates a large number of similarity metric functions in parallel on a graphics processing unit. Images from a cadaver and a patient were used for evaluation. The registration error was 0.83 mm and 1.97 mm for cadaver and patient images respectively. The average registration time for 60 trials was 4.4 seconds. The patient study demonstrated robustness of the proposed algorithm against a moderate anatomical deformation.

  4. Series of aerial images over Marais des Cygnes National Wildlife Refuge, acquired in 1950

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This dataset includes 10 georeferenced images, acquired on July 13, 1950 over portions of Marais des Cygnes National Refuge in eastern Kansas. This data set is a...

  5. Series of aerial images over Marais des Cygnes National Wildlife Refuge, acquired in 1957

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This dataset includes 8 georeferenced images, acquired on May 5th, 6th and 26th, 1957 over portions of Marais des Cygnes National Refuge in eastern Kansas. This data...

  6. Series of aerial images over Bear River Migratory Bird Refuge, acquired in 1937

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This dataset includes 40 georeferenced images, acquired on September 25th, October 12th-13th, November 10th and December 1st, 1937 over portions of Bear River...

  7. Information extraction and CT reconstruction of liver images based on diffraction enhanced imaging

    Institute of Scientific and Technical Information of China (English)

    Chunhong Hu; Tao Zhao; Lu Zhang; Hui Li; Xinyan Zhao; Shuqian Luo

    2009-01-01

    X-ray phase-contrast imaging (PCI) is a new emerging imaging technique that generates a high spatial resolution and high contrast of biological soft tissues compared to conventional radiography. Herein a biomedical application of diffraction enhanced imaging (DEI) is presented. As one of the PCI methods, DEI derives contrast from many different kinds of sample information, such as the sample's X-ray absorption, refraction gradient and ultra-small-angle X-ray scattering (USAXS) properties, and the sample information is expressed by three parametric images. Combined with computed tomography (CT), DEI-CT can produce 3D volumetric images of the sample and can be used for investigating micro-structures of biomedical samples. Our DEI experiments for fiver samples were implemented at the topog-raphy station of Beijing Synchrotron Radiation Facility (BSRF). The results show that by using our provided information extraction method and DEI-CT reconstruction approach, the obtained parametric images clearly display the inner structures of liver tissues and the morphology of blood vessels. Furthermore, the reconstructed 3D view of the fiver blood vessels exhibits the micro blood vessels whose minimum diameter is on the order of about tens of microns, much better than its conventional CT reconstruction at a millimeter resolution.In conclusion, both the information extraction method and DEI-CT have the potential for use in biomedical micro-structures analysis.

  8. Dose efficiency consideration for volume-of-interest breast imaging using x-ray differential phase-contrast CT

    Science.gov (United States)

    Cai, Weixing; Ning, Ruola

    2009-02-01

    The newly developed differential phase-contrast (DPC) imaging technique has attracted increasing interest among researchers. In a DPC system, the self-imaging effect and the phase-stepping method are implemented through three gratings to manifest phase contrast, and differentiated phase images can be obtained. An important advantage of this technique is that hospital-grade x-ray tubes can be used, allowing much higher x-ray output power and faster image processing than with micro-focus in-line phase-contrast imaging. A DPC-CT system can acquire images from different view angles along a circular orbit, and tomographic images can be reconstructed. However, the principle of DPC imaging requires multiple exposures to compute any differentiated phase image at each view angle, which raises concerns about radiation exposure via x-ray dose. Computer simulations are carried out to study the dose efficiency for DPC-CT for volume-of-interest breast imaging. A conceptual CBCT/DPC-CT hybrid imaging system and a numerical breast phantom are designed for this study. A FBP-type reconstruction algorithm is optimized for the VOI reconstruction. Factors including the x-ray flux and detector pixel size are considered and their effects on reconstruction image quality in terms of noise level and contrast-to-noise ratio are investigated. The results indicate that with a pixel size of 20 microns and a dose level of 5.7mGy, which is equivalent to the patient dose of a two-view mammography screening or a dedicated CBCT breast imaging scan, much better tissue contrast and spatial resolution can be achieved using the DPC-CT technique. It is very promising for possible application at pathology-level in vivo study for human breasts.

  9. Hotspot quantification of myocardial focal tracer uptake from molecular targeted SPECT/CT images: experimental validation

    Science.gov (United States)

    Liu, Yi-Hwa; Sahul, Zakir; Weyman, Christopher A.; Ryder, William J.; Dione, Donald P.; Dobrucki, Lawrence W.; Mekkaoui, Choukri; Brennan, Matthew P.; Hu, Xiaoyue; Hawley, Christi; Sinusas, Albert J.

    2008-03-01

    We have developed a new single photon emission computerized tomography (SPECT) hotspot quantification method incorporating extra cardiac activity correction and hotspot normal limit estimation. The method was validated for estimation accuracy of myocardial tracer focal uptake in a chronic canine model of myocardial infarction (MI). Dogs (n = 4) at 2 weeks post MI were injected with Tl-201 and a Tc-99m-labeled hotspot tracer targeted at matrix metalloproteinases (MMPs). An external point source filled with Tc-99m was used for a reference of absolute radioactivity. Dual-isotope (Tc-99m/Tl-201) SPECT images were acquired simultaneously followed by an X-ray CT acquisition. Dogs were sacrificed after imaging for myocardial gamma well counting. Images were reconstructed with CT-based attenuation correction (AC) and without AC (NAC) and were quantified using our quantification method. Normal limits for myocardial hotspot uptake were estimated based on 3 different schemes: maximum entropy, meansquared-error minimization (MSEM) and global minimization. Absolute myocardial hotspot uptake was quantified from SPECT images using the normal limits and compared with well-counted radioactivity on a segment-by-segment basis (n = 12 segments/dog). Radioactivity was expressed as % injected dose (%ID). There was an excellent correlation (r = 0.78-0.92) between the estimated activity (%ID) derived using the SPECT quantitative approach and well-counting, independent of AC. However, SPECT quantification without AC resulted in the significant underestimation of radioactivity. Quantification using SPECT with AC and the MSEM normal limit yielded the best results compared with well-counting. In conclusion, focal myocardial "hotspot" uptake of a targeted radiotracer can be accurately quantified in vivo using a method that incorporates SPECT imaging with AC, an external reference, background scatter compensation, and a suitable normal limit. This hybrid SPECT/CT approach allows for the serial

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

    Energy Technology Data Exchange (ETDEWEB)

    Kratz, Baerbel; Ens, Svitlana; Mueller, Jan; Buzug, Thorsten M. [Institute of Medical Engineering, University of Luebeck, 23538 Luebeck (Germany)

    2011-07-15

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

  11. Multislice CT of the pelvis: dose reduction with regard to image quality using 16-row CT

    Energy Technology Data Exchange (ETDEWEB)

    Gurung, Jessen; Khan, M. Fawad; Maataoui, Adel; Herzog, C.; Vogl, Thomas J. [Johann Wolfgang Goethe University, Institute for Diagnostic and Interventional Radiology, Frankfurt am Main (Germany); Bux, R.; Bratzke, H. [Johann Wolfgang Goethe University, Institute for Forensic Medicine, Frankfurt am Main (Germany); Ackermann, Hanns [Johann Wolfgang Goethe University, Institute for Epidemiology and Medical Statistics, Frankfurt am Main (Germany)

    2005-09-01

    To optimize examination protocols of 16-row multi-detector CT (MDCT) of pelvis for dose reduction with regard to image quality. MDCT of pelvis was performed on 12 cadaver specimens with stepwise reduction of tube current from 160 mA (113, 80, 56, 40, 28) to 20 mA at 120 kV. Scan parameters were 16 x 1.5 mm collimation. Reconstructions of axial and coronal images were used for evaluation of cortex, trabeculum, image quality, image noise, acetabulum and iliosacral (ISJ) joints. After data were blinded, evaluation of images was done by three radiologists according to 5-point Likert scale. Accuracy of the observers in sorting films according to dose reduction was determined with kappa coefficient. Mean values of image evaluation were determined. Pronounced deterioration of image quality for all criteria was observed between 80 and 28 mA. Adequate image quality was obtained at 40 mA [effective dose (E): 2.2 mSv, CTDI{sub w}: 2.8 mGy] for criterion detailed definition of acetabulum and ISJ and at 80 mA (E: 4.4 mSv, CTDI{sub w}: 5.6 mGy) for remaining criteria. Moderate agreement was observed between the three observers (kappa coefficient: 0.31). All observers were excellent in arranging images according to decreasing dose. Using 16-row MDCT image quality of pelvis is acceptable at 80 mA and 120 kV. This translates into a dose reduction of 33% of average value of the nationwide survey of the German Roentgen Society (1999) for this type of examination. (orig.)

  12. Accuracy of quantitative reconstructions in SPECT/CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Shcherbinin, S; Celler, A [Department of Radiology, University of British Columbia, 366-828 West 10th Avenue, Vancouver BC, V5Z 1L8 (Canada); Belhocine, T; Vanderwerf, R; Driedger, A [Department of Nuclear Medicine, London Health Sciences Centre, 375 South Street, PO Box 5375, London ON, N6A 4G5 (Canada)], E-mail: shcher2@interchange.ubc.ca

    2008-09-07

    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.

  13. Pulmonary cryptococcosis in rheumatoid arthritis (RA) patients: Comparison of imaging characteristics among RA, acquired immunodeficiency syndrome, and immunocompetent patients

    Energy Technology Data Exchange (ETDEWEB)

    Yanagawa, Noriyo, E-mail: noriyo_yana@ybb.ne.jp [Departments of Radiology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-8-22, Honkomagome, Bunkyo-ku, Tokyo 113-8677 (Japan); Sakai, Fumikazu [Department of Diagnostic Radiology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka-shi, Saitama 350-1298 (Japan); Takemura, Tamiko [Department of Pathology, Japanese Red Cross Medical Center, 4-1-22 Hiroo, Shibuya-ku, Tokyo 150-8935 (Japan); Ishikawa, Satoru [Department of Respiratory Medicine, National Hospital Organization Chiba-East-Hospital, 673 Nitona-cho, Chuo-ku, Chiba-shi, Chiba 260-8712 (Japan); Takaki, Yasunobu [Departments of Radiology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-8-22, Honkomagome, Bunkyo-ku, Tokyo 113-8677 (Japan); Hishima, Tsunekazu [Department of Pathology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-8-22, Honkomagome, Bunkyo-ku, Tokyo 113-8677 (Japan); Kamata, Noriko [Departments of Radiology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-8-22, Honkomagome, Bunkyo-ku, Tokyo 113-8677 (Japan)

    2013-11-01

    Purpose: The imaging characteristics of cryptococcosis in rheumatoid arthritis (RA) patients were analyzed by comparing them with those of acquired immunodeficiency syndrome (AIDS) and immunocompetent patients, and the imaging findings were correlated with pathological findings. Methods: Two radiologists retrospectively compared the computed tomographic (CT) findings of 35 episodes of pulmonary cryptococcosis in 31 patients with 3 kinds of underlying states (10 RA, 12 AIDS, 13 immunocompetent), focusing on the nature, number, and distribution of lesions. The pathological findings of 18 patients (8 RA, 2 AIDS, 8 immunocompetent) were analyzed by two pathologists, and then correlated with imaging findings. Results: The frequencies of consolidation and ground glass attenuation (GGA) were significantly higher, and the frequency of peripheral distribution was significantly lower in the RA group than in the immunocompetent group. Peripheral distribution was less common and generalized distribution was more frequent in the RA group than in the AIDS group. The pathological findings of the AIDS and immunocompetent groups reflected their immune status: There was lack of a granuloma reaction in the AIDS group, and a complete granuloma reaction in the immunocompetent group, while the findings of the RA group varied, including a complete granuloma reaction, a loose granuloma reaction and a hyper-immune reaction. Cases with the last two pathologic findings were symptomatic and showed generalized or central distribution on CT. Conclusion: Cryptococcosis in the RA group showed characteristic radiological and pathological findings compared with the other 2 groups.

  14. CT imaging vs. traditional radiographic imaging for evaluating Harris Lines in tibiae

    DEFF Research Database (Denmark)

    Primeau, Charlotte; Jakobsen, Lykke Schrøder; Lynnerup, Niels

    2016-01-01

    This paper is the first to systematically investigate computer tomography (CT) images vs. ordinary flat plane radiography for evaluating Harris Lines (HL) on tibiae. Harris Lines are traditionally investigated using radiographic images and recorded as either present or absent, or by counting...

  15. Lesion area detection using source image correlation coefficient for CT perfusion imaging.

    Science.gov (United States)

    Fan Zhu; Rodriguez Gonzalez, David; Carpenter, Trevor; Atkinson, Malcolm; Wardlaw, Joanna

    2013-09-01

    Computer tomography (CT) perfusion imaging is widely used to calculate brain hemodynamic quantities such as cerebral blood flow, cerebral blood volume, and mean transit time that aid the diagnosis of acute stroke. Since perfusion source images contain more information than hemodynamic maps, good utilization of the source images can lead to better understanding than the hemodynamic maps alone. Correlation-coefficient tests are used in our approach to measure the similarity between healthy tissue time-concentration curves and unknown curves. This information is then used to differentiate penumbra and dead tissues from healthy tissues. The goal of the segmentation is to fully utilize information in the perfusion source images. Our method directly identifies suspected abnormal areas from perfusion source images and then delivers a suggested segmentation of healthy, penumbra, and dead tissue. This approach is designed to handle CT perfusion images, but it can also be used to detect lesion areas in magnetic resonance perfusion images.

  16. Multislice CT scans in patients on extracorporeal membrane oxygenation: Emphasis on hemodynamic changes and imaging pitfalls

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Kao Lang; Wang, Yu Feng; Chang, Yeun Chung; Huang, Shu Chien; Chen, Shyh Jye; Chang, Chin Chen [National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei (China); Tsang, Yuk Ming [Dept. of Medical Imaging, Far Eastern Memorial Hospital, New Taipei City (China)

    2014-06-15

    This pictorial review provides the principles of extracorporeal membrane oxygenation (ECMO) support and associated CT imaging features with emphasis on the hemodynamic changes and possible imaging pitfalls encountered. It is important that radiologists in ECMO centers apply well-designed imaging protocols and familiarize themselves with post-contrast CT imaging findings in patients on ECMO.

  17. Volume-of-change cone-beam CT for image-guided surgery

    Science.gov (United States)

    Lee, Junghoon; Webster Stayman, J.; Otake, Yoshito; Schafer, Sebastian; Zbijewski, Wojciech; Khanna, A. Jay; Prince, Jerry L.; Siewerdsen, Jeffrey H.

    2012-08-01

    C-arm cone-beam CT (CBCT) can provide intraoperative 3D imaging capability for surgical guidance, but workflow and radiation dose are the significant barriers to broad utilization. One main reason is that each 3D image acquisition requires a complete scan with a full radiation dose to present a completely new 3D image every time. In this paper, we propose to utilize patient-specific CT or CBCT as prior knowledge to accurately reconstruct the aspects of the region that have changed by the surgical procedure from only a sparse set of x-rays. The proposed methods consist of a 3D-2D registration between the prior volume and a sparse set of intraoperative x-rays, creating digitally reconstructed radiographs (DRRs) from the registered prior volume, computing difference images by subtracting DRRs from the intraoperative x-rays, a penalized likelihood reconstruction of the volume of change (VOC) from the difference images, and finally a fusion of VOC reconstruction with the prior volume to visualize the entire surgical field. When the surgical changes are local and relatively small, the VOC reconstruction involves only a small volume size and a small number of projections, allowing less computation and lower radiation dose than is needed to reconstruct the entire surgical field. We applied this approach to sacroplasty phantom data obtained from a CBCT test bench and vertebroplasty data with a fresh cadaver acquired from a C-arm CBCT system with a flat-panel detector. The VOCs were reconstructed from a varying number of images (10-66 images) and compared to the CBCT ground truth using four different metrics (mean squared error, correlation coefficient, structural similarity index and perceptual difference model). The results show promising reconstruction quality with structural similarity to the ground truth close to 1 even when only 15-20 images were used, allowing dose reduction by the factor of 10-20.

  18. SU-C-17A-03: Evaluation of Deformable Image Registration Methods Between MRI and CT for Prostate Cancer Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Wen, N; Glide-Hurst, C; Zhong, H; Chin, K; Kumarasiri, A; Liu, C; Liu, M; Siddiqui, S [I Chetty, Henry Ford Health System, Detroit, MI (United States)

    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.

  19. Whole-organ CT perfusion of the pancreas: impact of iterative reconstruction on image quality, perfusion parameters and radiation dose in 256-slice CT-preliminary findings.

    Directory of Open Access Journals (Sweden)

    Qian Xie

    Full Text Available BACKGROUND: This study was performed to assess whether iterative reconstruction can reduce radiation dose while maintaining acceptable image quality, and to investigate whether perfusion parameters vary from conventional filtered back projection (FBP at the low-tube-voltage (80-kVp during whole-pancreas perfusion examination using a 256-slice CT. METHODS: 76 patients with known or suspected pancreatic mass underwent whole-pancreas perfusion by a 256-slice CT. High- and low-tube-voltage CT images were acquired. 120-kVp image data (protocol A and 80-kVp image data (protocol B were reconstructed with conventional FBP, and 80-kVp image data were reconstructed with iDose(4 (protocol C iterative reconstruction. The image noise; contrast-to-noise ratio (CNR relative to muscle for the pancreas, liver, and aorta; and radiation dose of each protocol were assessed quantitatively. Overall image quality was assessed qualitatively. Among 76 patients, 23 were eventually proven to have a normal pancreas. Perfusion parameters of normal pancreas in each protocol including blood volume, blood flow, and permeability-surface area product were measured. RESULTS: In the quantitative study, protocol C reduced image noise by 36.8% compared to protocol B (P<0.001. Protocol C yielded significantly higher CNR relative to muscle for the aorta, pancreas and liver compared to protocol B (P<0.001, and offered no significant difference compared to protocol A. In the qualitative study, protocols C and A gained similar scores and protocol B gained the lowest score for overall image quality (P<0.001. Mean effective doses were 23.37 mSv for protocol A and 10.81 mSv for protocols B and C. There were no significant differences in the normal pancreas perfusion values among three different protocols. CONCLUSION: Low-tube-voltage and iDose(4 iterative reconstruction can dramatically decrease the radiation dose with acceptable image quality during whole-pancreas CT perfusion and have no

  20. Improving the false-negative rate of CT in acute appendicitis-Reassessment of CT images by body imaging radiologists: A blinded prospective study

    Energy Technology Data Exchange (ETDEWEB)

    Poortman, Pieter [Department of Surgery, St Elisabeth Hospital, Tilburg (Netherlands)], E-mail: ppoortman@wlz.nl; Lohle, Paul N.M. [Department of Surgery, St Elisabeth Hospital, Tilburg (Netherlands)], E-mail: plohle@elisabeth.nl; Schoemaker, Cees M. [Department of Surgery, St Elisabeth Hospital, Tilburg (Netherlands)], E-mail: mcschoemaker@elisabeth.nl; Cuesta, Miguel A. [Department of Surgery, VU Medical Centre, Amsterdam (Netherlands)], E-mail: ma.cuesta@vumc.nl; Oostvogel, Henk J.M. [Department of Surgery, St Elisabeth Hospital, Tilburg (Netherlands)], E-mail: h.oostvogel@elisabeth.nl; Lange-de Klerk, Elly S.M. de [Department of Epidemiology and Biostatistics, VU Medical Centre, Amsterdam (Netherlands)], E-mail: esm.delange@vumc.nl; Hamming, Jaap F. [Department of Surgery, Leiden University Medical Centre (Netherlands)], E-mail: j.f.hamming@lumc.nl

    2010-04-15

    Purpose: To compare the accuracy of computed tomography (CT) analyzed by individual radiology staff members and body imaging radiologists in a non-academic teaching hospital for the diagnosis of acute appendicitis. Patients and methods: In a prospective study 199 patients with suspected acute appendicitis were examined with unenhanced CT. CT images were pre-operatively analyzed by one of the 12 members of the radiology staff. In a later stage two body imaging radiologist reassessed all CT images without knowledge of the surgical findings and without knowledge of the primary CT diagnosis. The results, independently reported, were correlated with surgical and histopathologic findings. Results: In 132 patients (66%) acute appendicitis was found at surgery, in 67 patients (34%) a normal appendix was found. The sensitivity of the primary CT analysis and of the reassessment was 76% and 88%, respectively; the specificity was 84% and 87%; the positive predictive value was 90% and 93%; the negative predictive value was 64% and 78%; and the accuracy was 78% and 87%. Conclusion: Reassessment of CT images for acute appendicitis by body imaging radiologists results in a significant improvement of sensitivity, negative predictive value and accuracy. To prevent false-negative interpretation of CT images in acute appendicitis the expertise of the attending radiologist should be considered.

  1. Underwater topography detection of Shuangzi Reefs with SAR images acquired in different time

    Institute of Scientific and Technical Information of China (English)

    YANG Jungang; ZHANG Jie; MENG Junmin

    2007-01-01

    Imaging mechanism of underwater topography by SAR and a underwater topography SAR detection model built on the theory of underwater topography detection with SAR image presented by Yuan Yeli are used to detect the underwater topography of Shuangzi Reefs in the Nansha Islands with three scenes of SAR images acquired in different time. Detection results of three SAR images are compared with the chart topography and the detection errors are analyzed. Underwater topography detection experiments of Shuangzi Reefs show that the detection model is practicable. The detection results indicate that SAR images acquired in different time also can be used to detect the underwater topography, and the detection results are affected by the ocean conditions in the SAR acquiring time.

  2. Fast kilovoltage/megavoltage (kVMV) breathhold cone-beam CT for image-guided radiotherapy of lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wertz, Hansjoerg; Stsepankou, Dzmitry; Blessing, Manuel; Boda-Heggemann, Judit; Hesser, Juergen; Lohr, Frank; Wenz, Frederik [Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim (Germany); Rossi, Michael; Gros, Uwe [Elekta Ltd, Hamburg (Germany); Knox, Chris; Brown, Kevin [Elekta Ltd, Crawley (United Kingdom); Walter, Cornelia, E-mail: hansjoerg.wertz@umm.d [Department of Radiation Oncology, Marienhospital Stuttgart (Germany)

    2010-08-07

    Long image acquisition times of 60-120 s for cone-beam CT (CBCT) limit the number of patients with lung cancer who can undergo volume image guidance under breathhold. We developed a low-dose dual-energy kilovoltage-megavoltage-cone-beam CT (kVMV-CBCT) based on a clinical treatment unit reducing imaging time to {<=}15 s. Simultaneous kVMV-imaging was achieved by dedicated synchronization hardware controlling the output of the linear accelerator (linac) based on detector panel readout signals, preventing imaging artifacts from interference of the linac's MV-irradiation and panel readouts. Optimization was performed to minimize the imaging dose. Single MV-projections, reconstructed MV-CBCT images and images of simultaneous 90{sup 0} kV- and 90{sup 0} MV-CBCT (180{sup 0} kVMV-CBCT) were acquired with different parameters. Image quality and imaging dose were evaluated and compared to kV-imaging. Hardware-based kVMV synchronization resulted in artifact-free projections. A combined 180{sup 0} kVMV-CBCT scan with a total MV-dose of 5 monitor units was acquired in 15 s and with sufficient image quality. The resolution was 5-6 line pairs cm{sup -1} (Catphan phantom). The combined kVMV-scan dose was equivalent to a kV-radiation scan dose of {approx}33 mGy. kVMV-CBCT based on a standard linac is promising and can provide ultra-fast online volume image guidance with low imaging dose and sufficient image quality for fast and accurate patient positioning for patients with lung cancer under breathhold.

  3. A clinical evaluation of total variation-Stokes image reconstruction strategy for low-dose CT imaging of the chest

    Science.gov (United States)

    Liu, Yan; Zhang, Hao; Moore, William; Bhattacharji, Priya; Liang, Zhengrong

    2015-03-01

    One hundred "normal-dose" computed tomography (CT) studies of the chest (i.e., 1,160 projection views, 120kVp, 100mAs) data sets were acquired from the patients who were scheduled for lung biopsy at Stony Brook University Hospital under informed consent approved by our Institutional Review Board. To mimic low-dose CT imaging scenario (i.e., sparse-view scan), sparse projection views were evenly extracted from the total 1,160 projections of each patient and the total radiation dose was reduced according to how many sparse views were selected. A standard filtered backprojection (FBP) algorithm was applied to the 1160 projections to produce reference images for comparison purpose. In the low-dose scenario, both the FBP and total variation-stokes (TVS) algorithms were applied to reconstruct the corresponding low-dose images. The reconstructed images were evaluated by an experienced thoracic radiologist against the reference images. Both the low-dose reconstructions and the reference images were displayed on a 4- megapixel monitor in soft tissue and lung windows. The images were graded by a five-point scale from 0 to 4 (0, nondiagnostic; 1, severe artifact with low confidence; 2, moderate artifact or moderate diagnostic confidences; 3, mild artifact or high confidence; 4, well depicted without artifacts). Quantitative evaluation measurements such as standard deviations for different tissue types and universal quality index were also studied and reported for the results. The evaluation concluded that the TVS can reduce the view number from 1,160 to 580 with slightly lower scores as the reference, resulting in a dose reduction to close 50%.

  4. RF Device for Acquiring Images of the Human Body

    Science.gov (United States)

    Gaier, Todd C.; McGrath, William R.

    2010-01-01

    A safe, non-invasive method for forming images through clothing of large groups of people, in order to search for concealed weapons either made of metal or not, has been developed. A millimeter wavelength scanner designed in a unique, ring-shaped configuration can obtain a full 360 image of the body with a resolution of less than a millimeter in only a few seconds. Millimeter waves readily penetrate normal clothing, but are highly reflected by the human body and concealed objects. Millimeter wave signals are nonionizing and are harmless to human tissues when used at low power levels. The imager (see figure) consists of a thin base that supports a small-diameter vertical post about 7 ft (=2.13 m) tall. Attached to the post is a square-shaped ring 2 in. (=5 cm) wide and 3 ft (=91 cm) on a side. The ring is oriented horizontally, and is supported halfway along one side by a connection to a linear bearing on the vertical post. A planar RF circuit board is mounted to the inside of each side of the ring. Each circuit board contains an array of 30 receivers, one transmitter, and digitization electronics. Each array element has a printed-circuit patch antenna coupled to a pair of mixers by a 90 coupler. The mixers receive a reference local oscillator signal to a subharmonic of the transmitter frequency. A single local oscillator line feeds all 30 receivers on the board. The resulting MHz IF signals are amplified and carried to the edge of the board where they are demodulated and digitized. The transmitted signal is derived from the local oscillator at a frequency offset determined by a crystal oscillator. One antenna centrally located on each side of the square ring provides the source illumination power. The total transmitted power is less than 100 mW, resulting in an exposure level that is completely safe to humans. The output signals from all four circuit boards are fed via serial connection to a data processing computer. The computer processes the approximately 1-MB

  5. CT enterography for Crohn's disease: optimal technique and imaging issues.

    Science.gov (United States)

    Baker, Mark E; Hara, Amy K; Platt, Joel F; Maglinte, Dean D T; Fletcher, Joel G

    2015-06-01

    CT enterography (CTE) is a common examination for patients with Crohn's disease. In order to achieve high quality, diagnostic images, proper technique is required. The purpose of this treatise is to review the processes and techniques that can optimize CTE for patients with suspected or known Crohn's disease. We will review the following: (1) how to start a CT enterography program; (2) workflow issues, including patient and ordering physician education and preparation; (3) oral contrast media options and administration regimens; (4) intravenous contrast media injection for uniphasic and multiphasic studies; (5) CTE radiation dose reduction strategies and the use of iterative reconstruction in lower dose examinations; (6) image reconstruction and interpretation; (7) imaging Crohn's patients in the acute or emergency department setting; (8) limitations of CTE as well as alternatives such as MRE or barium fluoroscopic examinations; and (9) dictation templates and a common nomenclature for reporting findings of CTE in Crohn's disease. Many of the issues discussed are summarized in the Abdominal Radiology Society Consensus MDCT Enterography Acquisition Protocol for Crohn's Disease.

  6. CT imaging in acute pulmonary embolism: diagnostic strategies

    Energy Technology Data Exchange (ETDEWEB)

    Wildberger, Joachim E.; Mahnken, Andreas H.; Das, Marco; Guenther, Rolf W. [University of Technology (RWTH), Department of Diagnostic Radiology, University Hospital, Aachen (Germany); Kuettner, Axel [Eberhard Karls University, Department of Diagnostic Radiology, Tuebingen (Germany); Lell, Michael [Friedrich Alexander University, Department of Diagnostic Radiology, Erlangen (Germany)

    2005-05-01

    Computed tomography pulmonary angiography (CTA) has increasingly become accepted as a widely available, safe, cost-effective, and accurate method for a quick and comprehensive diagnosis of acute pulmonary embolism (PE). Pulmonary catheter angiography is still considered the gold standard and final imaging method in many diagnostic algorithms. However, spiral CTA has become established as the first imaging test in clinical routine due to its high negative predictive value for clinically relevant PE. Despite the direct visualization of clot material, depiction of cardiac and pulmonary function in combination with the quantification of pulmonary obstruction helps to grade the severity of PE for further risk stratification and to monitor the effect of thrombolytic therapy. Because PE and deep venous thrombosis are two different aspects of the same disease, additional indirect CT venography may be a valuable addition to the initial diagnostic algorithm - if this was positive for PE - and demonstration of the extent and localization of deep venous thrombosis has an impact on clinical management. Additional and alternate diagnoses add to the usefulness of this method. Using advanced multislice spiral CT technology, some practitioners have advocated CTA as the sole imaging tool for routine clinical assessment in suspected acute PE. This will simplify standards of practice in the near future. (orig.)

  7. Evaluation of five image registration tools for abdominal CT: pitfalls and opportunities with soft anatomy

    Science.gov (United States)

    Lee, Christopher P.; Xu, Zhoubing; Burke, Ryan P.; Baucom, Rebeccah; Poulose, Benjamin K.; Abramson, Richard G.; Landman, Bennett A.

    2015-03-01

    Image registration has become an essential image processing technique to compare data across time and individuals. With the successes in volumetric brain registration, general-purpose software tools are beginning to be applied to abdominal computed tomography (CT) scans. Herein, we evaluate five current tools for registering clinically acquired abdominal CT scans. Twelve abdominal organs were labeled on a set of 20 atlases to enable assessment of correspondence. The 20 atlases were pairwise registered based on only intensity information with five registration tools (affine IRTK, FNIRT, Non-Rigid IRTK, NiftyReg, and ANTs). Following the brain literature, the Dice similarity coefficient (DSC), mean surface distance, and Hausdorff distance were calculated on the registered organs individually. However, interpretation was confounded due to a significant proportion of outliers. Examining the retrospectively selected top 1 and 5 atlases for each target revealed that there was a substantive performance difference between methods. To further our understanding, we constructed majority vote segmentation with the top 5 DSC values for each organ and target. The results illustrated a median improvement of 85% in DSC between the raw results and majority vote. These experiments show that some images may be well registered to some targets using the available software tools, but there is significant room for improvement and reveals the need for innovation and research in the field of registration in abdominal CTs. If image registration is to be used for local interpretation of abdominal CT, great care must be taken to account for outliers (e.g., atlas selection in statistical fusion).

  8. Whole-body CT in polytrauma patients: the effect of arm position on abdominal image quality when using a human phantom

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Pil-Hyun [Yonsei University, Wonju (Korea, Republic of); Wonju Christian Hospital, Wonju (Korea, Republic of); Kim, Hee-Joung; Lee, Chang-Lae; Kim, Dae-Hong [Yonsei University, Wonju (Korea, Republic of); Lee, Won-Hyung; Jeon, Sung-Su [Wonju Christian Hospital, Wonju (Korea, Republic of)

    2012-06-15

    For a considerable number of emergency computed tomography (CT) scans, patients are unable to position their arms above their head due to traumatic injuries. The arms-down position has been shown to reduce image quality with beam-hardening artifacts in the dorsal regions of the liver, spleen, and kidneys, rendering these images non-diagnostic. The purpose of this study was to evaluate the effect of arm position on the image quality in patients undergoing whole-body CT. We acquired CT scans with various acquisition parameters at voltages of 80, 120, and 140 kVp and an increasing tube current from 200 to 400 mAs in 50 mAs increments. The image noise and the contrast assessment were considered for quantitative analyses of the CT images. The image noise (IN), the contrast-to-noise ratio (CNR), the signal-to-noise ratio (SNR), and the coefficient of variation (COV) were evaluated. Quantitative analyses of the experiments were performed with CT scans representative of five different arm positions. Results of the CT scans acquired at 120 kVp and 250 mAs showed high image quality in patients with both arms raised above the head (SNR: 12.4, CNR: 10.9, and COV: 8.1) and both arms flexed at the elbows on the chest (SNR: 11.5, CNR: 10.2, and COV: 8.8) while the image quality significantly decreased with both arms in the down position (SNR: 9.1, CNR: 7.6, and COV: 11). Both arms raised, one arm raised, and both arms flexed improved the image quality compared to arms in the down position by reducing beam-hardening and streak artifacts caused by the arms being at the side of body. This study provides optimal methods for achieving higher image quality and lower noise in abdominal CT for trauma patients.

  9. Whole-body CT in polytrauma patients: The effect of arm position on abdominal image quality when using a human phantom

    Science.gov (United States)

    Jeon, Pil-Hyun; Kim, Hee-Joung; Lee, Chang-Lae; Kim, Dae-Hong; Lee, Won-Hyung; Jeon, Sung-Su

    2012-06-01

    For a considerable number of emergency computed tomography (CT) scans, patients are unable to position their arms above their head due to traumatic injuries. The arms-down position has been shown to reduce image quality with beam-hardening artifacts in the dorsal regions of the liver, spleen, and kidneys, rendering these images non-diagnostic. The purpose of this study was to evaluate the effect of arm position on the image quality in patients undergoing whole-body CT. We acquired CT scans with various acquisition parameters at voltages of 80, 120, and 140 kVp and an increasing tube current from 200 to 400 mAs in 50 mAs increments. The image noise and the contrast assessment were considered for quantitative analyses of the CT images. The image noise (IN), the contrast-to-noise ratio (CNR), the signal-to-noise ratio (SNR), and the coefficient of variation (COV) were evaluated. Quantitative analyses of the experiments were performed with CT scans representative of five different arm positions. Results of the CT scans acquired at 120 kVp and 250 mAs showed high image quality in patients with both arms raised above the head (SNR: 12.4, CNR: 10.9, and COV: 8.1) and both arms flexed at the elbows on the chest (SNR: 11.5, CNR: 10.2, and COV: 8.8) while the image quality significantly decreased with both arms in the down position (SNR: 9.1, CNR: 7.6, and COV: 11). Both arms raised, one arm raised, and both arms flexed improved the image quality compared to arms in the down position by reducing beam-hardening and streak artifacts caused by the arms being at the side of body. This study provides optimal methods for achieving higher image quality and lower noise in abdominal CT for trauma patients.

  10. Computational modeling and analysis for left ventricle motion using CT/Echo image fusion

    Science.gov (United States)

    Kim, Ji-Yeon; Kang, Nahyup; Lee, Hyoung-Euk; Kim, James D. K.

    2014-03-01

    In order to diagnose heart disease such as myocardial infarction, 2D strain through the speckle tracking echocardiography (STE) or the tagged MRI is often used. However out-of-plane strain measurement using STE or tagged MRI is inaccurate. Therefore, strain for whole organ which are analyzed by simulation of 3D cardiac model can be applied in clinical diagnosis. To simulate cardiac contraction in a cycle, cardiac physical properties should be reflected in cardiac model. The myocardial wall in left ventricle is represented as a transversely orthotropic hyperelastic material, with the fiber orientation varying sequentially from the epicardial surface, through about 0° at the midwall, to the endocardial surface. A time-varying elastance model is simulated to contract myocardial fiber, and physiological intraventricular systolic pressure curves are employed for the cardiac dynamics simulation in a cycle. And an exact description of the cardiac motion should be acquired in order that essential boundary conditions for cardiac simulation are obtained effectively. Real time cardiac motion can be acquired by using echocardiography and exact cardiac geometrical 3D model can be reconstructed using 3D CT data. In this research, image fusion technology from CT and echocardiography is employed in order to consider patient-specific left ventricle movement. Finally, longitudinal strain from speckle tracking echocardiography which is known to fit actual left ventricle deformation relatively well is used to verify these results.

  11. FDG PET/CT imaging in canine cancer patients

    DEFF Research Database (Denmark)

    Hansen, Anders Elias; McEvoy, Fintan; Engelholm, Svend Aage;

    2011-01-01

    and organs in canine cancer patients. FDG PET/CT was performed in 14 dogs including, nine mesenchymal tumors, four carcinomas, and one incompletely excised mast cell tumor. A generally higher FDG uptake was observed in carcinomas relative to sarcomas. Maximum SUV of carcinomas ranged from 7.6 to 27.......0, and for sarcomas from 2.0 to 10.6. The FDG SUV of several organs and tissues, including regional brain uptake is reported, to serve as a reference for future FDG PET studies in canine cancer patients. Several potential pitfalls have been recognized in interpretation of FDG PET images of human patients, a number...

  12. Metastatic meningioma: positron emission tomography CT imaging findings.

    LENUS (Irish Health Repository)

    Brennan, C

    2010-12-01

    The imaging findings of a case of metastasing meningioma are described. The case illustrates a number of rare and interesting features. The patient presented with haemoptysis 22 years after the initial resection of an intracranial meningioma. CT demonstrated heterogeneous masses with avid peripheral enhancement without central enhancement. Blood supply to the larger lesion was partially from small feeding vessels from the inferior pulmonary vein. These findings correlate with a previously published case in which there was avid uptake of fluoro-18-deoxyglucose peripherally with lesser uptake centrally. The diagnosis of metastasing meningioma was confirmed on percutaneous lung tissue biopsy.

  13. Metastatic meningioma: positron emission tomography CT imaging findings

    Science.gov (United States)

    Brennan, C; O'Connor, O J; O'Regan, K N; Keohane, C; Dineen, J; Hinchion, J; Sweeney, B; Maher, M M

    2010-01-01

    The imaging findings of a case of metastasing meningioma are described. The case illustrates a number of rare and interesting features. The patient presented with haemoptysis 22 years after the initial resection of an intracranial meningioma. CT demonstrated heterogeneous masses with avid peripheral enhancement without central enhancement. Blood supply to the larger lesion was partially from small feeding vessels from the inferior pulmonary vein. These findings correlate with a previously published case in which there was avid uptake of fluoro-18-deoxyglucose peripherally with lesser uptake centrally. The diagnosis of metastasing meningioma was confirmed on percutaneous lung tissue biopsy. PMID:21088084

  14. CT images of an anthropomorphic and anthropometric male pelvis phantom

    Energy Technology Data Exchange (ETDEWEB)

    Matos, Andrea S.D. de; Campos, Tarcisio P.R. de, E-mail: campos@nuclear.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pos-graduacao em Ciencias e Tecnicas Nucleares

    2009-07-01

    Actually, among of the most often neoplasm types are the cancer of prostate, bladder and intestine. The incidence of the intestine neoplasm in Brazil is at fourth among the most frequent tumors of the male sex, barely close to the stomach, lung and prostate incidences. Phantoms are objects used as simulators for investigating ionizing radiation transport on humans, especially during radiation therapy or radiological diagnostic. The purpose of this work is the achievement of a set of computerized tomography (CT) images of a male pelvis phantom, with anthropomorphic and anthropometric features. It investigates and analyses the set of phantom CT images in according to a correspondent human pelvis one. The reason to develop a pelvis phantom is the needs of reproducing well established spatial dose distribution in radiation therapy, especially during calibration and protocol setup for various pelvis neoplasms. It aims to produce dose optimization on radiation therapy, improving health tissue protection and keeping control tumor dose. A male pelvis phantom with similar shape made of equivalent tissues was built for simulating the ionizing radiation transport to the human body. At the phantom, pelvis organs were reproduced including the bladder, the intestine, the prostate, the muscular and greasy tissue, as well as the bone tissue and the skin. A set of CT images was carried out in axial thin sections of 2mm thickness. As results, the constituent tissues had a tomography response on Hounsfield scale similar to values found on the human pelvis. Each tissue has its respective Hounsfield value, demonstrated here. The CT images also show that the organs have equivalent anthropometric measures and anthropomorphic features of the radiological human anatomy. The anatomical physical arrangement of the organs is also similar to of the pelvis human male, having the scales of gray and numerical scale of Hounsfield compatible with the scale of the human tissue. The phantom presents

  15. IT Infrastructure to support the secondary use of routinely acquired clinical imaging data for research.

    Science.gov (United States)

    Leung, Kai Yan Eugene; van der Lijn, Fedde; Vrooman, Henri A; Sturkenboom, Miriam C J M; Niessen, Wiro J

    2015-01-01

    We propose an infrastructure for the automated anonymization, extraction and processing of image data stored in clinical data repositories to make routinely acquired imaging data available for research purposes. The automated system, which was tested in the context of analyzing routinely acquired MR brain imaging data, consists of four modules: subject selection using PACS query, anonymization of privacy sensitive information and removal of facial features, quality assurance on DICOM header and image information, and quantitative imaging biomarker extraction. In total, 1,616 examinations were selected based on the following MRI scanning protocols: dementia protocol (246), multiple sclerosis protocol (446) and open question protocol (924). We evaluated the effectiveness of the infrastructure in accessing and successfully extracting biomarkers from routinely acquired clinical imaging data. To examine the validity, we compared brain volumes between patient groups with positive and negative diagnosis, according to the patient reports. Overall, success rates of image data retrieval and automatic processing were 82.5 %, 82.3 % and 66.2 % for the three protocol groups respectively, indicating that a large percentage of routinely acquired clinical imaging data can be used for brain volumetry research, despite image heterogeneity. In line with the literature, brain volumes were found to be significantly smaller (p-value <0.001) in patients with a positive diagnosis of dementia (915 ml) compared to patients with a negative diagnosis (939 ml). This study demonstrates that quantitative image biomarkers such as intracranial and brain volume can be extracted from routinely acquired clinical imaging data. This enables secondary use of clinical images for research into quantitative biomarkers at a hitherto unprecedented scale.

  16. CT and MR Imagings of Semicircular Canal Aplasia

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Chung Hee; Hong, Hyun Sook; Yi, Beom Ha; Cha, Jang Gyu; Park, Seong Jin; Kim, Dae Ho; Lee, Hae Kyung; Kim, Shi Chan [Soonchunhyang University Bucheon Hospital, Bucheon (Korea, Republic of)

    2009-07-15

    To evaluate the clinical, CT and MR imaging findings of semicircular canal (SCC) aplasia and to evaluate if a correlation exists between these findings and the associated anomalies or syndromes. This study retrospectively reviewed the CT and MRI findings of five patients with SCC aplasia. The CT and MR findings were analyzed for SCC, direction of facial nerve canal, cochlea, vestibule, oval or round window, middle ear ossicles, and internal auditory canal (IAC). The subjects included three boys and two girls ranging in age from one to 120 months (mean age; 51 months). Four of the subjects had the CHARGE syndrome, and one had the Goldenhar syndrome. Moreover, four subjects had sensorineural hearing loss and one had combined hearing loss. The course of the facial nerve canal was abnormal in all five cases. Moreover, trapped cochlea and dysplastic modiolus were each observed in one case. Four subjects had atresia of the oval window; whereas ankylosis of the ossicles was present in three subjects. IAC stenosis was present in one patient with the CHARGE syndrome. The aberrant course of the facial nerve canal, atresia of the oval window, and abnormal ossicles were frequently associated in patients with SCC aplasia. In addition, the Goldenhar and CHARGE syndromes were also commonly associated syndromes.

  17. Ultra-filtration measurement using CT imaging technology

    Energy Technology Data Exchange (ETDEWEB)

    Lu Junfeng [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, No.2 Beiyitiao Street, Zhongguancun, Haidian District, Beijing, 100190 (China); Lu Wenqiang, E-mail: junfenglu@mail.ipc.ac.c [Graduate University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing, 100049 (China)

    2009-02-01

    As a functional unit in the hemodialysis process, dialyzer captured quite a few medical research interests since 1980s. In the design of dialyzer or in the ongoing hemodialysis process, to estimate the ultra-filtration amount of a dialyzer, the sideway loss of the running blood flow through hollow fibers or filtration channels should be measured. This further leads to the measurement of the blood flow inside the dialyzer. For this measurement, a non-invasive method is highly desired because of the high-dense bundled hollow fibers or packed channels inside the dialyzer. As non-invasive measurement tools, CT (Computed Tomography) technologies were widely used for tissue, bone, and cancerous clinical analyses etc .... Thus, in this paper, a CT system is adopted to predict the blood flow inside a hollow fiber dialyzer. In view of symmetric property of the hollow fiber dialyzer, the largest cutting plane that parallels to the cylindrical dialyzer was analyzed by the CT system dynamically. And then, a noninvasive image analysis method used to predict the ultra-filtration amount is proposed.

  18. Comparison of spectral CT imaging methods based a photon-counting detector: Experimental study

    Science.gov (United States)

    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.

  19. Comparison of spectral CT imaging methods based a photon-counting detector: Experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngjin [Department of Radiological Science, College of Health Science, Eulji University, 553 Sangseong-daero, Seongnam, Gyeonggi-do 461-713 (Korea, Republic of); Lee, Seungwan, E-mail: slee1@konyang.ac.kr [Department of Radiological Science, College of Medical Science, Konyang University, 158 Gwanjeodong-ro, Daejeon 302-812 (Korea, Republic of); Kim, Hee-Joung [Department of Radiological Science, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Kangwon-do 220-710 (Korea, Republic of)

    2016-04-11

    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.

  20. Direct visualization of regions with lowered bone mineral density in dual-energy CT images of vertebrae

    Science.gov (United States)

    Wesarg, Stefan; Erdt, Marius; Kafchitsas, Konstantinos; Khan, M. Fawad

    2011-03-01

    Dual-energy CT allows for a better material differentiation than conventional CT. For the purpose of osteoporosis diagnosis, a detection of regions with lowered bone mineral density (BMD) is of high clinical interest. Based on an existing biophysical model of the trabecular bone in vertebrae a new method for directly highlighting those low density regions in the image data has been developed. For this, we combine image data acquired at 80 kV and 140 kV with information about the BMD range in different vertebrae and derive a method for computing a color enhanced image which clearly indicates low density regions. An evaluation of our method which compares it with a quantitative method for BMD assessment shows a very good correspondence between both methods. The strength of our method lies in its simplicity and speed.

  1. Skeletal scintigraphy and SPECT/CT in orthopedic imaging; Knochenszintigrafie und SPECT/CT bei orthopaedischen Fragestellungen

    Energy Technology Data Exchange (ETDEWEB)

    Klaeser, B.; Walter, M.; Krause, T. [Inselspital Bern (Switzerland). Universitaetsklinik fuer Nuklearmedizin

    2011-03-15

    Multi-modality imaging with SPECT-CT in orthopaedics combines the excellent sensitivity of scintigraphy with the morphological information of CT as a key for specific interpretation of findings in bone scans. The result is an imaging modality with the clear potential to prove of value even in a competitive setting dominated by MRI, and to significantly add to diagnostic imaging in orthopaedics. SPECT-CT is of great value in the diagnostic evaluation after fractures, and - in contrast to MRI - it is well suited for imaging in patients with osteosyntheses and metallic implants. In sports medicine, SPECT-CT allows for a sensitive and specific detection of osseous stress reactions before morphological changes become detectable by CT or MRI. In patients with osseous pain syndromes, actively evolving degenerative changes as a cause of pain can be identified and accurately localized. Further, particularly prospective diagnostic studies providing comparative data are needed to strengthen the position of nuclear imaging in orthopaedics and sports medicine and to help implementing SPECT/CT in diagnostic algorithms. (orig.)

  2. Deep convolutional networks for pancreas segmentation in CT imaging

    Science.gov (United States)

    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.

  3. Feasibility study of CT perfusion imaging for prostate carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Cullu, Nesat [Mugla Sitki Kocman University, School of Medicine, Department of Radiology, Mugla (Turkey); Atatuerk University, School of Medicine, Department of Radiology, Erzurum (Turkey); Kantarci, Mecit; Ogul, Hayri; Pirimoglu, Berhan; Karaca, Leyla; Kizrak, Yesim [Atatuerk University, School of Medicine, Department of Radiology, Erzurum (Turkey); Adanur, Senol; Koc, Erdem; Polat, Ozkan [Atatuerk University, School of Medicine, Department of Urology, Erzurum (Turkey); Okur, Aylin [Atatuerk University, School of Medicine, Department of Radiology, Erzurum (Turkey); Bozok University, School of Medicine, Department of Radiology, Yozgat (Turkey)

    2014-09-15

    The aim of this feasibility study was to obtain initial data with which to assess the efficiency of perfusion CT imaging (CTpI) and to compare this with magnetic resonance imaging (MRI) in the diagnosis of prostate carcinoma. This prospective study involved 25 patients with prostate carcinoma undergoing MRI and CTpI. All analyses were performed on T2-weighted images (T2WI), apparent diffusion coefficient (ADC) maps, diffusion-weighted images (DWI) and CTp images. We compared the performance of T2WI combined with DWI and CTp alone. The study was approved by the local ethics committee, and written informed consent was obtained from all patients. Tumours were present in 87 areas according to the histopathological results. The diagnostic performance of the T2WI+DWI+CTpI combination was significantly better than that of T2WI alone for prostate carcinoma (P < 0.001). The diagnostic value of CTpI was similar to that of T2WI+DWI in combination. There were statistically significant differences in the blood flow and permeability surface values between prostate carcinoma and background prostate on CTp images. CTp may be a valuable tool for detecting prostate carcinoma and may be preferred in cases where MRI is contraindicated. If this technique is combined with T2WI and DWI, its diagnostic value is enhanced. (orig.)

  4. CT paging arteriography with a multidetector-row CT. Advantages in splanchnic arterial imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Seiji [Keio Univ., Tokyo (Japan). School of Medicine

    1999-11-01

    The purpose of this study is to assess the utility of CT paging arteriography with a multidetector-row CT as a replacement for conventional angiography in the evaluation of splanchnic arterial anomalies. Sixty-three patients underwent CT paging arteriography with a multidetector-row CT. In the 56 patients with conventional angiographic correlation, there was only one minor disagreement with CT paging arteriography. In the 7 patients who underwent IVDSA (intra venous digital subtraction angiography), CT paging arteriography defined four hepatic arterial anomalies which could not be depicted by IVDSA. In conclusion, CT paging arteriography provides noninvasive means to identify splanchnic arterial anomalies. (author)

  5. Imaging of community-acquired pneumonia: Roles of imaging examinations, imaging diagnosis of specific pathogens and discrimination from noninfectious diseases

    Institute of Scientific and Technical Information of China (English)

    Atsushi; Nambu; Katsura; Ozawa; Noriko; Kobayashi; Masao; Tago

    2014-01-01

    This article reviews roles of imaging examinations in the management of community-acquired pneumonia(CAP), imaging diagnosis of specific CAP and discrimination between CAP and noninfectious diseases. Chest radiography is usually enough to confirm the diagnosis of CAP, whereas computed tomography is required to suggest specific pathogens and to discriminate from noninfectious diseases. Mycoplasma pneumoniae pneumonia, tuberculosis, Pneumocystis jirovecii pneumonia and some cases of viral pneumonia sometimes show specific imaging findings. Peribronchial nodules, especially tree-in-bud appearance, are fairly specific for infection. Evidences of organization, such as concavity of the opacities, traction bronchiectasis, visualization of air bronchograms over the entire length of the bronchi, or mild parenchymal distortion are suggestive of organizing pneumonia. We will introduce tips to effectively make use of imaging examinations in the management of CAP.

  6. MUTUAL INFORMATION BASED 3D NON-RIGID REGISTRATION OF CT/MR ABDOMEN IMAGES

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A mutual information based 3D non-rigid registration approach was proposed for the registration of deformable CT/MR body abdomen images. The Parzen Windows Density Estimation (PWDE) method is adopted to calculate the mutual information between the two modals of CT and MRI abdomen images. By maximizing MI between the CT and MR volume images, the overlapping part of them reaches the biggest, which means that the two body images of CT and MR matches best to each other. Visible Human Project (VHP) Male abdomen CT and MRI Data are used as experimental data sets. The experimental results indicate that this approach of non-rigid 3D registration of CT/MR body abdominal images can be achieved effectively and automatically, without any prior processing procedures such as segmentation and feature extraction, but has a main drawback of very long computation time. Key words: medical image registration; multi-modality; mutual information; non-rigid; Parzen window density estimation

  7. Imaging of congenital anomalies and acquired lesions of the inner ear.

    Science.gov (United States)

    Krombach, Gabriele A; Honnef, Dagmar; Westhofen, Martin; Di Martino, Ercole; Günther, Rolf W

    2008-02-01

    Imaging of the temporal bone is under continous developement. In the recent decades the technical advances of magnetic resonance imaging and computed tomography have contributed to improved imaging quality in assessment of the temporal bone. Dedicated imaging protocols have been developed and are routinely employed in most institutions. However, imaging interpretation remains challenging, since the temporal bone is an anatomically highly complex region and most diseases of the inner ear occur with low incidence, so that even radiologists experienced in the field may be confronted with such entities for the first time. The current review gives an overview about symptoms and imaging appearance of malformations and acquired lesion of the inner ear.

  8. Imaging of congenital anomalies and acquired lesions of the inner ear

    Energy Technology Data Exchange (ETDEWEB)

    Krombach, Gabriele A.; Honnef, Dagmar; Guenther, Rolf W. [RWTH Aachen University Hospital, Department of Diagnostic Radiology, Aachen (Germany); Westhofen, Martin [RWTH Aachen University Hospital, Department of Otorhinolaryngology and Head and Neck Surgery, Aachen (Germany); Di Martino, Ercole [DIAKO Hospital Bremen, Department of Otorhinolaryngology and Head and Neck Surgery, Bremen (Germany)

    2008-02-15

    Imaging of the temporal bone is under continous developement. In the recent decades the technical advances of magnetic resonance imaging and computed tomography have contributed to improved imaging quality in assessment of the temporal bone. Dedicated imaging protocols have been developed and are routinely employed in most institutions. However, imaging interpretation remains challenging, since the temporal bone is an anatomically highly complex region and most diseases of the inner ear occur with low incidence, so that even radiologists experienced in the field may be confronted with such entities for the first time. The current review gives an overview about symptoms and imaging appearance of malformations and acquired lesion of the inner ear. (orig.)

  9. Towards real-time 3D US to CT bone image registration using phase and curvature feature based GMM matching.

    Science.gov (United States)

    Brounstein, Anna; Hacihaliloglu, Ilker; Guy, Pierre; Hodgson, Antony; Abugharbieh, Rafeef

    2011-01-01

    In order to use pre-operatively acquired computed tomography (CT) scans to guide surgical tool movements in orthopaedic surgery, the CT scan must first be registered to the patient's anatomy. Three-dimensional (3D) ultrasound (US) could potentially be used for this purpose if the registration process could be made sufficiently automatic, fast and accurate, but existing methods have difficulties meeting one or more of these criteria. We propose a near-real-time US-to-CT registration method that matches point clouds extracted from local phase images with points selected in part on the basis of local curvature. The point clouds are represented as Gaussian Mixture Models (GMM) and registration is achieved by minimizing the statistical dissimilarity between the GMMs using an L2 distance metric. We present quantitative and qualitative results on both phantom and clinical pelvis data and show a mean registration time of 2.11 s with a mean accuracy of 0.49 mm.

  10. Investigation of the effect of tube voltage and imaging geometry on phase contrast imaging for a micro-CT system

    Energy Technology Data Exchange (ETDEWEB)

    Gui Jianbao; Zou Jing; Rong Junyan [Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen (China); Key Lab for Biomedical Informatics and Health Engineering, Chinese Academy of Sciences, Shenzhen (China); Hu Zhanli [Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen (China); Key Lab for Biomedical Informatics and Health Engineering, Chinese Academy of Sciences, Shenzhen (China); Graduate University of Chinese Academy of Sciences (China); Zhang Qiyang; Zheng Hairong [Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen (China); Key Lab for Biomedical Informatics and Health Engineering, Chinese Academy of Sciences, Shenzhen (China); Xia Dan, E-mail: dan.xia@siat.ac.cn [Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen (China); Key Lab for Biomedical Informatics and Health Engineering, Chinese Academy of Sciences, Shenzhen (China)

    2012-03-21

    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 {mu}m and a cooled X-ray CCD detector with pixel size of 24 {mu}m. 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.

  11. Investigation of the effect of tube voltage and imaging geometry on phase contrast imaging for a micro-CT system

    Science.gov (United States)

    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.

  12. An experimental cone-beam micro-CT system for small animal imaging

    Science.gov (United States)

    Zhu, Shouping; Tian, Jie; Yan, Guorui; Qin, Chenghu; Liu, Junting

    2009-02-01

    An experimental cone-beam Micro-CT system for small animal imaging is presented in the paper. The system is designed to obtain high-resolution anatomic information and will be integrated with our bioluminescence tomography system. A flat panel X-ray detector (CMOS technology with a column CsI scintillator plate, 50 micron pixel size, 120 mm × 120 mm photodiode area) and a micro-focus X-ray source (13 to 40 μm of focal spot size) are used in the system. The object (mouse or rat) is placed on a three-degree (two translations and one rotation) programming stage and could be located to an accurate position in front of the detector. The large field of view (FOV) of the system allows us to acquire the whole body imaging of a normal mouse in one scanning which usually takes about 6 to 15 minutes. Raw data from X-ray detector show spatial variation caused by dark image offset, pixel gain and defective pixels, therefore data pre-processing is needed before reconstruction. Geometry calibrations are also used to reduce the artifacts caused by geometric misalignment. In order to accelerate FDK filtered backprojection method, we develop a reconstruction software using GPU hardware in our system. System spacial resolution and image uniformity and voxel noise have been assessed and mouse reconstruction images are illuminated in the paper. Experiment results show that this system is suitable for small animal imaging.

  13. Quantum noise properties of CT images with anatomical textured backgrounds across reconstruction algorithms: FBP and SAFIRE

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, Justin, E-mail: justin.solomon@duke.edu [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Samei, Ehsan [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 and Departments of Biomedical Engineering and Electrical and Computer Engineering, Pratt School of Engineering, Duke University, Durham, North Carolina 27705 (United States)

    2014-09-15

    Purpose: Quantum noise properties of CT images are generally assessed using simple geometric phantoms with uniform backgrounds. Such phantoms may be inadequate when assessing nonlinear reconstruction or postprocessing algorithms. The purpose of this study was to design anatomically informed textured phantoms and use the phantoms to assess quantum noise properties across two clinically available reconstruction algorithms, filtered back projection (FBP) and sinogram affirmed iterative reconstruction (SAFIRE). Methods: Two phantoms were designed to represent lung and soft-tissue textures. The lung phantom included intricate vessel-like structures along with embedded nodules (spherical, lobulated, and spiculated). The soft tissue phantom was designed based on a three-dimensional clustered lumpy background with included low-contrast lesions (spherical and anthropomorphic). The phantoms were built using rapid prototyping (3D printing) technology and, along with a uniform phantom of similar size, were imaged on a Siemens SOMATOM Definition Flash CT scanner and reconstructed with FBP and SAFIRE. Fifty repeated acquisitions were acquired for each background type and noise was assessed by estimating pixel-value statistics, such as standard deviation (i.e., noise magnitude), autocorrelation, and noise power spectrum. Noise stationarity was also assessed by examining the spatial distribution of noise magnitude. The noise properties were compared across background types and between the two reconstruction algorithms. Results: In FBP and SAFIRE images, noise was globally nonstationary for all phantoms. In FBP images of all phantoms, and in SAFIRE images of the uniform phantom, noise appeared to be locally stationary (within a reasonably small region of interest). Noise was locally nonstationary in SAFIRE images of the textured phantoms with edge pixels showing higher noise magnitude compared to pixels in more homogenous regions. For pixels in uniform regions, noise magnitude was

  14. Automatic transperineal ultrasound probe positioning based on CT scan for image guided radiotherapy

    Science.gov (United States)

    Camps, S. M.; Verhaegen, F.; Paiva Fonesca, G.; de With, P. H. N.; Fontanarosa, D.

    2017-03-01

    Image interpretation is crucial during ultrasound image acquisition. A skilled operator is typically needed to verify if the correct anatomical structures are all visualized and with sufficient quality. The need for this operator is one of the major reasons why presently ultrasound is not widely used in radiotherapy workflows. To solve this issue, we introduce an algorithm that uses anatomical information derived from a CT scan to automatically provide the operator with a patient-specific ultrasound probe setup. The first application we investigated, for its relevance to radiotherapy, is 4D transperineal ultrasound image acquisition for prostate cancer patients. As initial test, the algorithm was applied on a CIRS multi-modality pelvic phantom. Probe setups were calculated in order to allow visualization of the prostate and adjacent edges of bladder and rectum, as clinically required. Five of the proposed setups were reproduced using a precision robotic arm and ultrasound volumes were acquired. A gel-filled probe cover was used to ensure proper acoustic coupling, while taking into account possible tilted positions of the probe with respect to the flat phantom surface. Visual inspection of the acquired volumes revealed that clinical requirements were fulfilled. Preliminary quantitative evaluation was also performed. The mean absolute distance (MAD) was calculated between actual anatomical structure positions and positions predicted by the CT-based algorithm. This resulted in a MAD of (2.8±0.4) mm for prostate, (2.5±0.6) mm for bladder and (2.8±0.6) mm for rectum. These results show that no significant systematic errors due to e.g. probe misplacement were introduced.

  15. Initial Experience of Using Dual-Energy CT with an Iodine Overlay Image for Hand Psoriatic Arthritis: Comparison Study with Contrast-enhanced MR Imaging.

    Science.gov (United States)

    Fukuda, Takeshi; Umezawa, Yoshinori; Tojo, Shinjiro; Yonenaga, Takenori; Asahina, Akihiko; Nakagawa, Hidemi; Fukuda, Kunihiko

    2017-07-01

    Purpose To determine the feasibility of dual-energy (DE) computed tomography (CT) with an iodine overlay image (IOI) for evaluation of psoriatic arthritis in the hand. Materials and Methods Approval from the institutional ethics committee and written informed consent from all patients were obtained. This prospective study included 16 patients who had psoriasis with finger joint symptoms from January 2015 to January 2016. Contrast material-enhanced (CE) DE CT and 1.5-T CE magnetic resonance (MR) imaging were performed within 1 month of each other. DE CT was performed with a tube voltage of 80 kV and 140 kV with use of a 0.4-mm tin filter. Images acquired with both modalities were evaluated by two radiologists independently by using a semiquantitative scoring system. Interreader agreement was calculated for each modality: Weighted κ values were calculated for synovitis, flexor tenosynovitis, and extensor peritendonitis, and κ values were calculated for periarticular inflammation. With consensus scores and CE MR images as the reference, the sensitivity and specificity of IOI DE CT for inflammatory lesions were calculated. Statistical analysis of discordant readings was performed by using the McNemar test. Results Interreader agreement for inflammatory lesions was excellent or good (weighted κ = 0.83 and κ = 0.75 in IOI DE CT; weighted κ = 0.81 and κ = 0.87 in CE MR imaging). The sensitivity and specificity of IOI DE CT were 0.78 and 0.87, respectively. Total agreement was 86.3%; however, there were significantly more lesions detected with IOI DE CT than with CE MR imaging alone (134 vs 20 lesions in 1120 evaluated items; P < .001). Sixty-nine percent of the abnormalities detected with IOI DE CT alone were located in distal interphalangeal joints. Conclusion IOI DE CT is a new imaging modality that may be useful for evaluating psoriatic arthritis in the hand, particularly in the detection of inflammatory lesions in small joints, and may be more useful than CE MR

  16. Assessment of pulmonary hypertension by CT and MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ley, Sebastian [Department of Radiology, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, 69120, Heidelberg (Germany); Department of Radiology, Johannes Gutenberg University, Langenbeckstrasse 1, 55131, Mainz (Germany); Kreitner, Karl-Friedrich; Heussel, Claus P. [Department of Radiology, Johannes Gutenberg University, Langenbeckstrasse 1, 55131, Mainz (Germany); Fink, Christian; Kauczor, Hans-Ulrich [Department of Radiology, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, 69120, Heidelberg (Germany); Borst, Mathias M. [Department of Internal Medicine III, Ruprecht-Karls University, Heidelberg (Germany)

    2004-03-01

    In the recent World Health Organization (WHO) classification the group of pulmonary arterial hypertension (PH) comprises the classic primary pulmonary hypertension and several conditions with definite or very high risk factors to develop pulmonary arterial hypertension. Therapeutic advances drive the need for a comprehensive pre-therapeutic evaluation for optimal treatment. Furthermore, follow-up examinations need to be performed to monitor changes in disease status and response to therapy. Up to now, the diagnostic imaging work-up of PH comprises mainly echocardiography, invasive right heart catheterization and ventilation/perfusion scintigraphy. Due to technical advances helical computed tomography (CT) and magnetic resonance imaging (MRI) became more important in the evaluation and for differential diagnosis of pulmonary arterial hypertension. Both modalities are reviewed and recommendations for clinical use are given. (orig.)

  17. [A novel denoising approach to SVD filtering based on DCT and PCA in CT image].

    Science.gov (United States)

    Feng, Fuqiang; Wang, Jun

    2013-10-01

    Because of various effects of the imaging mechanism, noises are inevitably introduced in medical CT imaging process. Noises in the images will greatly degrade the quality of images and bring difficulties to clinical diagnosis. This paper presents a new method to improve singular value decomposition (SVD) filtering performance in CT image. Filter based on SVD can effectively analyze characteristics of the image in horizontal (and/or vertical) directions. According to the features of CT image, we can make use of discrete cosine transform (DCT) to extract the region of interest and to shield uninterested region so as to realize the extraction of structure characteristics of the image. Then we transformed SVD to the image after DCT, constructing weighting function for image reconstruction adaptively weighted. The algorithm for the novel denoising approach in this paper was applied in CT image denoising, and the experimental results showed that the new method could effectively improve the performance of SVD filtering.

  18. Constrain static target kinetic iterative image reconstruction for 4D cardiac CT imaging

    Science.gov (United States)

    Alessio, Adam M.; La Riviere, Patrick J.

    2011-03-01

    Iterative image reconstruction offers improved signal to noise properties for CT imaging. A primary challenge with iterative methods is the substantial computation time. This computation time is even more prohibitive in 4D imaging applications, such as cardiac gated or dynamic acquisition sequences. In this work, we propose only updating the time-varying elements of a 4D image sequence while constraining the static elements to be fixed or slowly varying in time. We test the method with simulations of 4D acquisitions based on measured cardiac patient data from a) a retrospective cardiac-gated CT acquisition and b) a dynamic perfusion CT acquisition. We target the kinetic elements with one of two methods: 1) position a circular ROI on the heart, assuming area outside ROI is essentially static throughout imaging time; and 2) select varying elements from the coefficient of variation image formed from fast analytic reconstruction of all time frames. Targeted kinetic elements are updated with each iteration, while static elements remain fixed at initial image values formed from the reconstruction of data from all time frames. Results confirm that the computation time is proportional to the number of targeted elements; our simulations suggest that 3 times reductions in reconstruction time. The images reconstructed with the proposed method have matched mean square error with full 4D reconstruction. The proposed method is amenable to most optimization algorithms and offers the potential for significant computation improvements, which could be traded off for more sophisticated system models or penalty terms.

  19. A novel super resolution scheme to acquire and process satellite images

    Science.gov (United States)

    Yin, Dong-yu; Su, Xiao-feng; Lin, Jian-chun; Wang, Gan-quan; Kuang, Ding-bo

    2013-09-01

    Geosynchronous satellite has obvious limitations for the weight and the scale of payloads, and large aperture optical system is not permitted. The optical diffraction limit of small aperture optical system has an adverse impact on the resolution of the acquired images. Therefore, how to get high resolution images using super-resolution technique with the acquired low resolution images becomes a popular problem investigated by researchers. Here, we present a novel scheme to acquire low resolution images and process them to achieve a high resolution image. Firstly, to acquire low resolution images, we adopt a special arrangement pattern of four CCD staggered arrays on the focal plane in the remote sensing satellite framework .These four CCD linear arrays are parallelized with a 0.25√2 pixel shift along the CCD direction and a 1.25 pixel shift along the scanning direction. The rotation angle between the two directions is 45 degree. The tilting sampling mode and the special arrangement pattern allow the sensor to acquire images with a smaller sampling interval which can give the resolution a greater enhancement. Secondly, to reconstruct a high resolution image of pretty good quality with a magnification factor 4, we propose a novel algorithm based on the iterative-interpolation super resolution algorithm (IISR) and the new edge-directed interpolation algorithm (NEDI). The new algorithm makes a critical improvement to NEDI and introduces it into the multi-frame interpolation in IISR. The algorithm can preserve the edges well and requires a relatively small number of low-resolution images to achieve better reconstruction accuracy .In the last part of the paper, we carry out a simulation experiment, and use MSE as the quality measure. The results demonstrate that our new scheme substantially improves the image resolution with both better quantitative quality and visual quality compared with some previous normal methods.

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

    Science.gov (United States)

    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.

  1. Can segmented 3D images be used for stenosis evaluation in coronary CT angiography?

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chunliang [Linkoeping Univ., Center for Medical Image Science and Visualization, Linkoeping (Sweden); Linkoeping Univ., Div. of Radiological Sciences, Linkoeping (Sweden)], e-mail: chunliang.wang@liu.se; Persson, Anders; De Geer, Jakob; Smedby, Oerjan [Linkoeping Univ., Center for Medical Image Science and Visualization, Linkoeping (Sweden); Linkoeping Univ., Div. of Radiological Sciences, Linkoeping (Sweden); Linkoeping Univ. Hospital, Dept. of Radiology, Linkoeping (Sweden); Engvall, Jan [Linkoeping Univ., Center for Medical Image Science and Visualization, Linkoeping (Sweden); Linkoeping Univ. Hospital, Dept. of Clinical Physiology, Linkoeping (Sweden); Czekierda, Waldemar; Bjoerkholm, Anders [Linkoeping Univ. Hospital, Dept. of Radiology, Linkoeping (Sweden); Fransson, Sven-Goeran [Linkoeping Univ., Div. of Radiological Sciences, Linkoeping (Sweden); Linkoeping Univ. Hospital, Dept. of Radiology, Linkoeping (Sweden)

    2012-10-15

    Background Thanks to the development of computed tomography (CT) scanners and computer software, accurate coronary artery segmentation can be achieved with minimum user interaction. However, the question remains whether we can use these segmented images for reliable diagnosis. Purpose To retrospectively evaluate the diagnostic accuracy of coronary CT angiography (CCTA) using segmented 3D data for the detection of significant stenosis. Material and Methods CCTA data-sets from 30 patients were acquired with a 64-slice CT scanner and segmented using the region growing (RG) method and the 'virtual contrast injection' (VC) method. Three types of images of each patient were reviewed by different reviewers for the presence of stenosis with diameter reduction of 50% or more. The evaluation was performed on four main arteries of each patient (120 arteries in total). For the original series, the reviewer was allowed to use all the 2D and 3D visualization tools available (conventional method). For the segmented results from RG and VC, only maximum intensity projection was used. Evaluation results were compared with catheter angiography (CA) for each artery in a blinded fashion. Results Overall, 34 arteries with significant stenosis were identified by CA. The percentage of evaluable arteries, accuracy and negative predictive value for detecting stenosis were, respectively, 86%, 74%, and 93% for the conventional method, 83%, 71%, and 92% for VC, and 64%, 56%, and 93% for RG. Accuracy was significantly lower for the RG method than for the other two methods (P < 0.01), whereas there was no significant difference in accuracy between the VC method and the conventional method (P = 0.22). Conclusion The diagnostic accuracy for the RG-segmented 3D data is lower than those with access to 2D images, whereas the VC method shows diagnostic accuracy similar to the conventional method.

  2. Kaposi sarcoma related to acquired immunodeficiency syndrome: hepatic findings on computed tomography and magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Daniel Nobrega da; Viana, Publio Cesar Cavalcante; Maciel, Rosangela Pereira; Rocha, Manoel de Souza; Gebrim, Eloisa Maria Mello Santiago [Universidade de Sao Paulo (USP), SP (Brazil). Hospital das Clinicas. Inst. de Radiologia]. E-mail: dnobrega@gmail.com

    2008-03-15

    Kaposi sarcoma is a neoplasm associated with immunosuppressive conditions, and involving blood and lymphatic vessels. It is the most frequent intrahepatic neoplasm in patients with acquired immunodeficiency syndrome. Computed tomography and magnetic resonance imaging demonstrate multiple small nodules, prominence and contrast-enhancement of periportal branches due to the presence of the neoplastic tissue. The authors report a case of a 47-year-old male patient with acquired immunodeficiency syndrome presenting disseminated Kaposi sarcoma. (author)

  3. Realistic simulation of reduced-dose CT with noise modeling and sinogram synthesis using DICOM CT images

    Energy Technology Data Exchange (ETDEWEB)

    Won Kim, Chang [Interdisciplinary Program of Bioengineering Major Seoul National University College of Engineering, San 56-1, Silim-dong, Gwanak-gu, Seoul 152-742, South Korea and Institute of Radiation Medicine, Seoul National University College of Medicine, 28, Yongon-dong, Chongno-gu, Seoul 110-744 (Korea, Republic of); Kim, Jong Hyo, E-mail: kimjhyo@snu.ac.kr [Department of Radiology, Institute of Radiation Medicine, Seoul National University College of Medicine, 28, Yongon-dong, Chongno-gu, Seoul, 110-744 (Korea, Republic of); Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, Gyeonggi-do, 443-270 (Korea, Republic of); Advanced Institutes of Convergence Technology, Seoul National University, Suwon, Gyeonggi-do, 443-270 (Korea, Republic of)

    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

  4. Technology and Technique Standards for Camera-Acquired Digital Dermatologic Images: A Systematic Review.

    Science.gov (United States)

    Quigley, Elizabeth A; Tokay, Barbara A; Jewell, Sarah T; Marchetti, Michael A; Halpern, Allan C

    2015-08-01

    Photographs are invaluable dermatologic diagnostic, management, research, teaching, and documentation tools. Digital Imaging and Communications in Medicine (DICOM) standards exist for many types of digital medical images, but there are no DICOM standards for camera-acquired dermatologic images to date. To identify and describe existing or proposed technology and technique standards for camera-acquired dermatologic images in the scientific literature. Systematic searches of the PubMed, EMBASE, and Cochrane databases were performed in January 2013 using photography and digital imaging, standardization, and medical specialty and medical illustration search terms and augmented by a gray literature search of 14 websites using Google. Two reviewers independently screened titles of 7371 unique publications, followed by 3 sequential full-text reviews, leading to the selection of 49 publications with the most recent (1985-2013) or detailed description of technology or technique standards related to the acquisition or use of images of skin disease (or related conditions). No universally accepted existing technology or technique standards for camera-based digital images in dermatology were identified. Recommendations are summarized for technology imaging standards, including spatial resolution, color resolution, reproduction (magnification) ratios, postacquisition image processing, color calibration, compression, output, archiving and storage, and security during storage and transmission. Recommendations are also summarized for technique imaging standards, including environmental conditions (lighting, background, and camera position), patient pose and standard view sets, and patient consent, privacy, and confidentiality. Proposed standards for specific-use cases in total body photography, teledermatology, and dermoscopy are described. The literature is replete with descriptions of obtaining photographs of skin disease, but universal imaging standards have not been developed

  5. PET-CT imaging fusion in the assessment of head and neck carcinoma; Fusao de imagens PET-TC na avaliacao do carcinoma espinocelular de cabeca e pescoco

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Denise Takehana dos [Sao Paulo Univ., SP (Brazil). Faculdade de Odontologia; Chojniak, Rubens [Hospital do Cancer A.C. Camargo, Sao Paulo, SP (Brazil). Dept. de Imagem; Lima, Eduardo Nobrega Pereira [Hospital do Cancer A.C. Camargo, Sao Paulo, SP (Brazil). Medicina Nuclear; Cavalcanti, Marcelo Gusmao Paraiso [Universidade de Sao Paulo, SP (Brazil). Faculdade de Odontologia. Dept. de Estomatologia]. E-mail: mgpcaval@usp.br

    2006-11-15

    Objective: The authors have established a methodological approach to evaluate head and neck squamous cell carcinoma aiming at identifying and distinguishing high metabolic activity inside the lesion, combining in a single examination, functional, metabolic and morphological data simultaneously acquired by means of different non-dedicated positron emission tomography (PET)-computed tomography (CT) device. Materials and Methods: The study population included 17 patients with head and neck squamous cell carcinoma submitted to a non-dedicated {sup 18} F-FDG-PET imaging at Department of Diagnostic Imaging of Hospital do Cancer, Sao Paulo, SP, Brazil. CT and {sup 18} F-FDG-PET images were simultaneously acquired in a non-dedicated device. The original data were transferred to an independent workstation by means of the Entegra 2 NT software to generate PET-CT imaging fusion. Results: The findings were defined as positive in the presence of a well defined focal area of increased radiopharmaceutical uptake in regions not related with the normal biodistribution of the tracer. Conclusion: The fusion of simultaneously acquired images in a single examination ({sup 18}F-FDGPET and CT) has allowed the topographic-metabolic mapping of the lesion as well as the localization of high metabolic activity areas inside the tumor, indicating recidivation or metastasis and widening the array of alternatives for radiotherapy or surgical planning. (author)

  6. Dose heterogeneity correction for low-energy brachytherapy sources using dual-energy CT images.

    Science.gov (United States)

    Mashouf, S; Lechtman, E; Lai, P; Keller, B M; Karotki, A; Beachey, D J; Pignol, J P

    2014-09-21

    Permanent seed implant brachytherapy is currently used for adjuvant radiotherapy of early stage prostate and breast cancer patients. The current standard for calculation of dose around brachytherapy sources is based on the AAPM TG-43 formalism, which generates the dose in a homogeneous water medium. Recently, AAPM TG-186 emphasized the importance of accounting for tissue heterogeneities. We have previously reported on a methodology where the absorbed dose in tissue can be obtained by multiplying the dose, calculated by the TG-43 formalism, by an inhomogeneity correction factor (ICF). In this work we make use of dual energy CT (DECT) images to extract ICF parameters. The advantage of DECT over conventional CT is that it eliminates the need for tissue segmentation as well as assignment of population based atomic compositions. DECT images of a heterogeneous phantom were acquired and the dose was calculated using both TG-43 and TG-43 [Formula: see text] formalisms. The results were compared to experimental measurements using Gafchromic films in the mid-plane of the phantom. For a seed implant configuration of 8 seeds spaced 1.5 cm apart in a cubic structure, the gamma passing score for 2%/2 mm criteria improved from 40.8% to 90.5% when ICF was applied to TG-43 dose distributions.

  7. Dose heterogeneity correction for low-energy brachytherapy sources using dual-energy CT images

    Science.gov (United States)

    Mashouf, S.; Lechtman, E.; Lai, P.; Keller, B. M.; Karotki, A.; Beachey, D. J.; Pignol, J. P.

    2014-09-01

    Permanent seed implant brachytherapy is currently used for adjuvant radiotherapy of early stage prostate and breast cancer patients. The current standard for calculation of dose around brachytherapy sources is based on the AAPM TG-43 formalism, which generates the dose in a homogeneous water medium. Recently, AAPM TG-186 emphasized the importance of accounting for tissue heterogeneities. We have previously reported on a methodology where the absorbed dose in tissue can be obtained by multiplying the dose, calculated by the TG-43 formalism, by an inhomogeneity correction factor (ICF). In this work we make use of dual energy CT (DECT) images to extract ICF parameters. The advantage of DECT over conventional CT is that it eliminates the need for tissue segmentation as well as assignment of population based atomic compositions. DECT images of a heterogeneous phantom were acquired and the dose was calculated using both TG-43 and TG-43 × \\text{ICF} formalisms. The results were compared to experimental measurements using Gafchromic films in the mid-plane of the phantom. For a seed implant configuration of 8 seeds spaced 1.5 cm apart in a cubic structure, the gamma passing score for 2%/2 mm criteria improved from 40.8% to 90.5% when ICF was applied to TG-43 dose distributions.

  8. The effects of gantry tilt on breast dose and image noise in cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, Michael E.; Gandhi, Diksha; Schmidt, Taly Gilat [Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233 (United States); Stevens, Grant M. [GE Healthcare, Waukesha, Wisconsin 53188 (United States); Foley, W. Dennis [Department of Radiology, Medical College of Wisconsin, Froedtert Memorial Lutheran Hospital, Milwaukee, Wisconsin 53226 (United States)

    2013-12-15

    Purpose: This study investigated the effects of tilted-gantry acquisition on image noise and glandular breast dose in females during cardiac computed tomography (CT) scans. Reducing the dose to glandular breast tissue is important due to its high radiosensitivity and limited diagnostic significance in cardiac CT scans.Methods: Tilted-gantry acquisition was investigated through computer simulations and experimental measurements. Upon IRB approval, eight voxelized phantoms were constructed from previously acquired cardiac CT datasets. Monte Carlo simulations quantified the dose deposited in glandular breast tissue over a range of tilt angles. The effects of tilted-gantry acquisition on breast dose were measured on a clinical CT scanner (CT750HD, GE Healthcare) using an anthropomorphic phantom with MOSFET dosimeters in the breast regions. In both simulations and experiments, scans were performed at gantry tilt angles of 0°–30°, in 5° increments. The percent change in breast dose was calculated relative to the nontilted scan for all tilt angles. The percent change in noise standard deviation due to gantry tilt was calculated in all reconstructed simulated and experimental images.Results: Tilting the gantry reduced the breast dose in all simulated and experimental phantoms, with generally greater dose reduction at increased gantry tilts. For example, at 30° gantry tilt, the dosimeters located in the superior, middle, and inferior breast regions measured dose reductions of 74%, 61%, and 9%, respectively. The simulations estimated 0%–30% total breast dose reduction across the eight phantoms and range of tilt angles. However, tilted-gantry acquisition also increased the noise standard deviation in the simulated phantoms by 2%–50% due to increased pathlength through the iodine-filled heart. The experimental phantom, which did not contain iodine in the blood, demonstrated decreased breast dose and decreased noise at all gantry tilt angles.Conclusions: Tilting the

  9. Open source deformable image registration system for treatment planning and recurrence CT scans

    DEFF Research Database (Denmark)

    Zukauskaite, Ruta; Brink, Carsten; Hansen, Christian Rønn

    2016-01-01

    manually contoured eight anatomical regions-of-interest (ROI) twice on pCT and once on rCT. METHODS: pCT and rCT images were deformably registered using the open source software elastix. Mean surface distance (MSD) and Dice similarity coefficient (DSC) between contours were used for validation of DIR...... on pCT. DSC for DIR varied between 0.58 and 0.79 for soft tissues and was 0.79 or higher for bony structures, and correlated with the volumes of ROIs (r = 0.5, p elastix in HNSCC on planning and recurrence CT scans is feasible...

  10. Importance of multidetector CT imaging in multiple trauma; Stellenwert der Multidetektor-CT bei Polytrauma

    Energy Technology Data Exchange (ETDEWEB)

    Linsenmaier, U. [HELIOS Kliniken Muenchen West, HELIOS Klinik Muenchen Perlach, Institut fuer Diagnostische und Interventionelle Radiologie, Muenchen (Germany); Geyer, L.L.; Reiser, M.; Wirth, S. [Klinikum der Ludwig-Maximilians-Universitaet, Institut fuer Klinische Radiologie, Muenchen (Germany); Koerner, M. [Radiologie Muehleninsel, Landshut (Germany)

    2014-09-15

    Diagnostic imaging of complex multiple trauma remains a challenge for any department providing modern emergency radiology (ER) service. An early and comprehensive approach for ER imaging is crucial for a priority-oriented and timely therapy concept with the aim of identifying potentially life-threatening injuries early and initiating appropriate treatment. The basic diagnostic approach still consists of focused ultrasound using focused assessment with sonography for trauma (FAST) and conventional radiography (CR), usually limited to a single supine chest x-ray for triaging patients undergoing immediate operations. Multidetector computed tomography (MDCT) has become established as early whole body CT (WBCT) as the undisputable diagnostic method. The detection rate of injuries by WBCT is outstanding and it improves the probability of survival by 20-25 % compared with all other previous methods. At the same time, the spatial and temporal resolution of MDCT was improved resulting in considerably shortened examination times but WBCT is still associated with a significant radiation exposure, even in the acute single use setting. Using modern scanner and dose reduction technology, including iterative reconstruction, a dose reduction of up to 40 % could be achieved. The substantial number of images in WBCT is another challenge; images must be processed priority-oriented, read and transferred to the picture archiving and communications system (PACS). For rapid diagnosis, volume image reading (VIR) offers additional options to keep the diagnostic process on time. Modern WBCT after multiple trauma is performed early, comprehensively and personalized so that WBCT improves the probability of survival by 20-25 %. (orig.) [German] Die Diagnostik komplexer Mehrfachverletzungen ist eine Herausforderung fuer die moderne radiologische Notfalldiagnostik. Eine umfassend angelegte, fruehe und praezise radiologische Diagnostik ist entscheidend fuer eine prioritaetenorientierte und

  11. Low dose dynamic CT myocardial perfusion imaging using a statistical iterative reconstruction method

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Yinghua [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); Chen, Guang-Hong [Department of Medical Physics and Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); Hacker, Timothy A.; Raval, Amish N. [Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53792 (United States); Van Lysel, Michael S.; Speidel, Michael A., E-mail: speidel@wisc.edu [Department of Medical Physics and Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States)

    2014-07-15

    Purpose: Dynamic CT myocardial perfusion imaging has the potential to provide both functional and anatomical information regarding coronary artery stenosis. However, radiation dose can be potentially high due to repeated scanning of the same region. The purpose of this study is to investigate the use of statistical iterative reconstruction to improve parametric maps of myocardial perfusion derived from a low tube current dynamic CT acquisition. Methods: Four pigs underwent high (500 mA) and low (25 mA) dose dynamic CT myocardial perfusion scans with and without coronary occlusion. To delineate the affected myocardial territory, an N-13 ammonia PET perfusion scan was performed for each animal in each occlusion state. Filtered backprojection (FBP) reconstruction was first applied to all CT data sets. Then, a statistical iterative reconstruction (SIR) method was applied to data sets acquired at low dose. Image voxel noise was matched between the low dose SIR and high dose FBP reconstructions. CT perfusion maps were compared among the low dose FBP, low dose SIR and high dose FBP reconstructions. Numerical simulations of a dynamic CT scan at high and low dose (20:1 ratio) were performed to quantitatively evaluate SIR and FBP performance in terms of flow map accuracy, precision, dose efficiency, and spatial resolution. Results: Forin vivo studies, the 500 mA FBP maps gave −88.4%, −96.0%, −76.7%, and −65.8% flow change in the occluded anterior region compared to the open-coronary scans (four animals). The percent changes in the 25 mA SIR maps were in good agreement, measuring −94.7%, −81.6%, −84.0%, and −72.2%. The 25 mA FBP maps gave unreliable flow measurements due to streaks caused by photon starvation (percent changes of +137.4%, +71.0%, −11.8%, and −3.5%). Agreement between 25 mA SIR and 500 mA FBP global flow was −9.7%, 8.8%, −3.1%, and 26.4%. The average variability of flow measurements in a nonoccluded region was 16.3%, 24.1%, and 937

  12. Development of a guideline on reading CT images of malignant pleural mesothelioma and selection of the reference CT films

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Huashi, E-mail: zhouhua@u-fukui.ac.jp [Department of Environmental Health, School of Medicine, University of Fukui, 23-3 Shimoaitsuki, Matsuoka, Eihezi-cho, Fukui Prefecture 910-1193 (Japan); Tamura, Taro, E-mail: tarou@u-fukui.ac.jp [Department of Environmental Health, School of Medicine, University of Fukui, 23-3 Shimoaitsuki, Matsuoka, Eihezi-cho, Fukui Prefecture 910-1193 (Japan); Kusaka, Yukinori, E-mail: kusakayk@gmail.com [Department of Environmental Health, School of Medicine, University of Fukui, 23-3 Shimoaitsuki, Matsuoka, Eihezi-cho, Fukui Prefecture 910-1193 (Japan); Suganuma, Narufumi, E-mail: nsuganuma@kochi-u.ac.jp [Department of Environmental Medicine, Kochi University School of Medicine (Japan); Subhannachart, Ponglada, E-mail: pongladas@gmail.com [Central Chest Disease Institute of Thailand, 39 Moo 9, Tiwanon Road, Muang Nonthaburi 11000 (Thailand); Vijitsanguan, Chomphunut, E-mail: Chompoo_vj@yahoo.com [Central Chest Disease Institute of Thailand, 39 Moo 9, Tiwanon Road, Muang Nonthaburi 11000 (Thailand); Noisiri, Weeraya, E-mail: weeraya_tat@yahoo.com [Central Chest Disease Institute of Thailand, 39 Moo 9, Tiwanon Road, Muang Nonthaburi 11000 (Thailand); Hering, Kurt G., E-mail: k.g.hering@t-online.de [Department of Diagnostic Radiology, Radiooncology and Nuclear Medicine, Radiological Clinic, Miner' s Hospital, Radiologische Klinik, Lansppaschaftskranhaus Dortmund, Wieckesweg 27 44309, Dortmund (Germany); Akira, Masanori, E-mail: akira@kch.hosp.go.jp [Department of Radiology, National Hospital Organization Kinki-Chuo Chest Medical Center, 1180 Nagasone-cho, Kita-ku, Sakai, Osaka 591-8555 (Japan); Itoh, Harumi, E-mail: hitoh@fmsrsa.fukui-med.ac.jp [Department of Environmental Health, School of Medicine, University of Fukui, 23-3 Shimoaitsuki, Matsuoka, Eihezi-cho, Fukui Prefecture 910-1193 (Japan); Department of Radiology, School of Medicine, University of Fukui, 23-3 Shimoaitsuki Matsuoka, Eiheizi-cho, Fukui Prefecture 910-1193 (Japan); and others

    2012-12-15

    Purpose: International experts developed a guideline on reading CT images of malignant pleural mesothelioma for radiologists and physicians. It is intended that it act as a supplement to the current International Classification of HRCT for Occupational and Environmental Respiratory Diseases. Methods: The research literatures on mesothelioma CT features were systematically reviewed. Ten mesothelioma CT features were adopted into the guideline prepared according to experts’ opinion. The terminology of mesothelioma CT features and mesothelioma probability were agreed by consensus of experts. The CT reference films for each mesothelioma feature were selected based on agreement by experts from 22 definite mesothelioma cases confirmed pathologically and immunohistochemically. To support the validity of the mesothelioma probability, 4 experts’ readings of CT films from 57 cases with or without mesothelioma were analyzed by kappa statistics between the experts; sensitivity and specificity for mesothelioma were also assessed. Results: The mesothelioma CT Guideline was developed, providing the terminology of CT features and the mesothelioma probability, the judgement of severity, the distribution of mesothelioma, and the revised CT reading sheet including mesothelioma items. The CT reference films with ten mesothelioma typical features were selected. The average linearly and quadratically weighted kappa of the agreement on the 4-point scale mesothelioma probability were 0.58 and 0.71, respectively. The average sensitivity and specificity for mesothelioma were 93.2% and 65.6%, respectively. Conclusion: The evidence-based mesothelioma CT Guideline developed may serve as a good educational tool to facilitate physicians in recognising mesothelioma and improve their proficiency in diagnosis of mesothelioma.

  13. Mirror-image lymph node in FDG PET/CT and SPECT/CT for sentinel node detection.

    Science.gov (United States)

    Domenech, Beatriz; Paredes, Pilar; Rubí, Sebastià; Pahisa, Jaume; Vidal-Sicart, Sergi; Pons, Francesca

    2014-03-01

    We report a case of a patient with presumed stage IB1 squamous cell carcinoma of the cervix in which FDG PET/CT scan revealed 1 hypermetabolic left iliac node suggestive to be malignant. Lymphoscintigraphy and SPECT/CT studies previous to sentinel node (SLN) biopsy revealed unilateral drainage in the right pelvis. Intraoperative pathological assessment of the SLN showed no tumoral involvement, and the hypermetabolic node revealed macrometastasis. Tumor node invasion can lead to a lymphatic blockage and become false-negative for SLN technique. Although FDG PET/CT has lower sensitivity than surgical staging, this case shows its value as a preoperative imaging technique.

  14. Concurrent Diffuse Pyelonephritis and Prostatitis: Discordant Findings on Sequential FDG PET/CT and 67Ga SPECT/CT Imaging.

    Science.gov (United States)

    Lucaj, Robert; Achong, Dwight M

    2017-01-01

    A 45-year-old man underwent FDG PET/CT for initial imaging evaluation of recurrent Escherichia coli urinary tract infections, which demonstrated no significant FDG uptake in either kidney and subtle FDG uptake in the right prostate lobe. Subsequent Ga SPECT/CT demonstrated abnormal intense gallium uptake throughout the right kidney and entire prostate gland, clearly discordant with PET/CT findings and consistent with unexpected concurrent pyelonephritis and prostatitis. Although FDG has effectively replaced Ga in everyday clinical practice, the current case serves as a reminder that there is still a role for Ga in the evaluation of genitourinary infections.

  15. Integration of PET-CT and cone-beam CT for image-guided radiotherapy with high image quality and registration accuracy

    Science.gov (United States)

    Wu, T.-H.; Liang, C.-H.; Wu, J.-K.; Lien, C.-Y.; Yang, B.-H.; Huang, Y.-H.; Lee, J. J. S.

    2009-07-01

    Hybrid positron emission tomography-computed tomography (PET-CT) system enhances better differentiation of tissue uptake of 18F-fluorodeoxyglucose (18F-FDG) and provides much more diagnostic value in the non-small-cell lung cancer and nasopharyngeal carcinoma (NPC). In PET-CT, high quality CT images not only offer diagnostic value on anatomic delineation of the tissues but also shorten the acquisition time for attenuation correction (AC) compared with PET-alone imaging. The linear accelerators equipped with the X-ray cone-beam computed tomography (CBCT) imaging system for image-guided radiotherapy (IGRT) provides excellent verification on position setup error. The purposes of our study were to optimize the CT acquisition protocols of PET-CT and to integrate the PET-CT and CBCT for IGRT. The CT imaging parameters were modified in PET-CT for increasing the image quality in order to enhance the diagnostic value on tumour delineation. Reproducibility and registration accuracy via bone co-registration algorithm between the PET-CT and CBCT were evaluated by using a head phantom to simulate a head and neck treatment condition. Dose measurement in computed tomography dose index (CTDI) was also estimated. Optimization of the CT acquisition protocols of PET-CT was feasible in this study. Co-registration accuracy between CBCT and PET-CT on axial and helical modes was in the range of 1.06 to 2.08 and 0.99 to 2.05 mm, respectively. In our result, it revealed that the accuracy of the co-registration with CBCT on helical mode was more accurate than that on axial mode. Radiation doses in CTDI were 4.76 to 18.5 mGy and 4.83 to 18.79 mGy on axial and helical modes, respectively. Registration between PET-CT and CBCT is a state-of-the-art registration technology which could provide much information on diagnosis and accurate tumour contouring on radiotherapy while implementing radiotherapy procedures. This novelty technology of PET-CT and cone-beam CT integration for IGRT may have a

  16. Integration of PET-CT and cone-beam CT for image-guided radiotherapy with high image quality and registration accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, T-H [Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, No. 110, Sec.1, Jianguo N.Rd, Taichung City 40201, Taiwan (China); Liang, C-H [Agfa Healthcare Systems Taiwan Co., Ltd., 6F, 237 Sung Chiang Road, Taipei, 104 Taiwan (China); Wu, J-K [Division of Radiation Oncology, Department of Oncology, and Cancer Research Center, National Taiwan University Hospital, No.7 Chung San South Road, Taipei, 104 Taiwan (China); Lien, C-Y [Institute of Biomedical Engineering, National Yang Ming University, No. 155, Sec.2, Linong Street, Taipei, 112 Taiwan (China); Yang, B-H; Lee, J J S [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, No. 155, Sec.2, Linong Street, Taipei, 112 Taiwan (China); Huang, Y-H [Department of Medical Imaing and Radiological Sciences, I-Shou University, No. 8, Yida Rd., Yanchao Township, Kaohsiung County 82445, Taiwan (China)], E-mail: jslee@ym.edu.tw

    2009-07-15

    Hybrid positron emission tomography-computed tomography (PET-CT) system enhances better differentiation of tissue uptake of {sup 18}F-fluorodeoxyglucose ({sup 18}F-FDG) and provides much more diagnostic value in the non-small-cell lung cancer and nasopharyngeal carcinoma (NPC). In PET-CT, high quality CT images not only offer diagnostic value on anatomic delineation of the tissues but also shorten the acquisition time for attenuation correction (AC) compared with PET-alone imaging. The linear accelerators equipped with the X-ray cone-beam computed tomography (CBCT) imaging system for image-guided radiotherapy (IGRT) provides excellent verification on position setup error. The purposes of our study were to optimize the CT acquisition protocols of PET-CT and to integrate the PET-CT and CBCT for IGRT. The CT imaging parameters were modified in PET-CT for increasing the image quality in order to enhance the diagnostic value on tumour delineation. Reproducibility and registration accuracy via bone co-registration algorithm between the PET-CT and CBCT were evaluated by using a head phantom to simulate a head and neck treatment condition. Dose measurement in computed tomography dose index (CTDI) was also estimated. Optimization of the CT acquisition protocols of PET-CT was feasible in this study. Co-registration accuracy between CBCT and PET-CT on axial and helical modes was in the range of 1.06 to 2.08 and 0.99 to 2.05 mm, respectively. In our result, it revealed that the accuracy of the co-registration with CBCT on helical mode was more accurate than that on axial mode. Radiation doses in CTDI were 4.76 to 18.5 mGy and 4.83 to 18.79 mGy on axial and helical modes, respectively. Registration between PET-CT and CBCT is a state-of-the-art registration technology which could provide much information on diagnosis and accurate tumour contouring on radiotherapy while implementing radiotherapy procedures. This novelty technology of PET-CT and cone-beam CT integration for IGRT

  17. Metal artifacts reduction using monochromatic images from spectral CT: Evaluation of pedicle screws in patients with scoliosis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yang, E-mail: wangzhang227@163.com [Department of Radiology, The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 (China); Qian, Bangping, E-mail: qianbangping@163.com [Spine Service, Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008 (China); Li, Baoxin, E-mail: wangzhi68@163.com [Department of Radiology, The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 (China); Qin, Guochu, E-mail: qgc7605@yahoo.com.cn [Department of Radiology, The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 (China); Zhou, Zhengyang, E-mail: zyzhou@nju.edu.cn [Department of Radiology, The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 (China); Qiu, Yong, E-mail: scoliosis2002@sina.com [Spine Service, Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008 (China); Sun, Xizhao, E-mail: sunxizhaonj@163.com [Department of Radiology and Urology, The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, No. 321 Zhongshan Road, Nanjing 210008 (China); Zhu, Bin, E-mail: gobin10266@163.com [Department of Radiology, The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 (China)

    2013-08-15

    Purpose: To evaluate the effectiveness of spectral CT in reducing metal artifacts caused by pedicle screws in patients with scoliosis. Materials and methods: Institutional review committee approval and written informed consents from patients were obtained. 18 scoliotic patients with a total of 228 pedicle screws who underwent spectral CT imaging were included in this study. Monochromatic image sets with and without the additional metal artifacts reduction software (MARS) correction were generated with photon energy at 65 keV and from 70 to 140 keV with 10 keV interval using the 80 kVp and 140 kVp projection sets. Polychromatic images corresponded to the conventional 140 kVp imaging were also generated from the same scan data as a control group. Both objective evaluation (screw width and quantitative artifacts index measurements) and subjective evaluation (depiction of pedicle screws, surrounding structures and their relationship) were performed. Results: Image quality of monochromatic images in the range from 110 to 140 keV (0.97 ± 0.28) was rated superior to the conventional polychromatic images (2.53 ± 0.54) and also better than monochromatic images with lower energy. Images of energy above 100 keV also give accurate measurement of the width of screws and relatively low artifacts index. The form of screws was slightly distorted in MARS reconstruction. Conclusions: Compared to conventional polychromatic images, monochromatic images acquired from dual-energy CT provided superior image quality with much reduced metal artifacts of pedicle screws in patients with scoliosis. Optimal energy range was found between 110 and 140 keV.

  18. Iodine contrast cone beam CT imaging of breast cancer

    Science.gov (United States)

    Partain, Larry; Prionas, Stavros; Seppi, Edward; Virshup, Gary; Roos, Gerhard; Sutherland, Robert; Boone, John

    2007-03-01

    An iodine contrast agent, in conjunction with an X-ray cone beam CT imaging system, was used to clearly image three, biopsy verified, cancer lesions in two patients. The lesions were approximately in the 10 mm to 6 mm diameter range. Additional regions were also enhanced with approximate dimensions down to 1 mm or less in diameter. A flat panel detector, with 194 μm pixels in 2 x 2 binning mode, was used to obtain 500 projection images at 30 fps with an 80 kVp X-ray system operating at 112 mAs, for an 8-9 mGy dose - equivalent to two view mammography for these women. The patients were positioned prone, while the gantry rotated in the horizontal plane around the uncompressed, pendant breasts. This gantry rotated 360 degrees during the patient's 16.6 sec breath hold. A volume of 100 cc of 320 mg/ml iodine-contrast was power injected at 4 cc/sec, via catheter into the arm vein of the patient. The resulting 512 x 512 x 300 cone beam CT data set of Feldkamp reconstructed ~(0.3 mm) 3 voxels were analyzed. An interval of voxel contrast values, characteristic of the regions with iodine contrast enhancement, were used with surface rendering to clearly identify up to a total of 13 highlighted volumes. This included the three largest lesions, that were previously biopsied and confirmed to be malignant. The other ten highlighted regions, of smaller diameters, are likely areas of increased contrast trapping unrelated to cancer angiogenesis. However the technique itself is capable of resolving lesions that small.

  19. Enhanced temporal resolution at cardiac CT with a novel CT image reconstruction algorithm: Initial patient experience

    Energy Technology Data Exchange (ETDEWEB)

    Apfaltrer, Paul, E-mail: paul.apfaltrer@medma.uni-heidelberg.de [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, PO Box 250322, 169 Ashley Avenue, Charleston, SC 29425 (United States); Institute of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim (Germany); Schoendube, Harald, E-mail: harald.schoendube@siemens.com [Siemens Healthcare, CT Division, Forchheim Siemens, Siemensstr. 1, 91301 Forchheim (Germany); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, PO Box 250322, 169 Ashley Avenue, Charleston, SC 29425 (United States); Allmendinger, Thomas, E-mail: thomas.allmendinger@siemens.com [Siemens Healthcare, CT Division, Forchheim Siemens, Siemensstr. 1, 91301 Forchheim (Germany); Tricarico, Francesco, E-mail: francescotricarico82@gmail.com [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, PO Box 250322, 169 Ashley Avenue, Charleston, SC 29425 (United States); Department of Bioimaging and Radiological Sciences, Catholic University of the Sacred Heart, “A. Gemelli” Hospital, Largo A. Gemelli 8, Rome (Italy); Schindler, Andreas, E-mail: andreas.schindler@campus.lmu.de [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, PO Box 250322, 169 Ashley Avenue, Charleston, SC 29425 (United States); Vogt, Sebastian, E-mail: sebastian.vogt@siemens.com [Siemens Healthcare, CT Division, Forchheim Siemens, Siemensstr. 1, 91301 Forchheim (Germany); Sunnegårdh, Johan, E-mail: johan.sunnegardh@siemens.com [Siemens Healthcare, CT Division, Forchheim Siemens, Siemensstr. 1, 91301 Forchheim (Germany); and others

    2013-02-15

    Objective: To evaluate the effect of a temporal resolution improvement method (TRIM) for cardiac CT on diagnostic image quality for coronary artery assessment. Materials and methods: The TRIM-algorithm employs an iterative approach to reconstruct images from less than 180° of projections and uses a histogram constraint to prevent the occurrence of limited-angle artifacts. This algorithm was applied in 11 obese patients (7 men, 67.2 ± 9.8 years) who had undergone second generation dual-source cardiac CT with 120 kV, 175–426 mAs, and 500 ms gantry rotation. All data were reconstructed with a temporal resolution of 250 ms using traditional filtered-back projection (FBP) and of 200 ms using the TRIM-algorithm. Contrast attenuation and contrast-to-noise-ratio (CNR) were measured in the ascending aorta. The presence and severity of coronary motion artifacts was rated on a 4-point Likert scale. Results: All scans were considered of diagnostic quality. Mean BMI was 36 ± 3.6 kg/m{sup 2}. Average heart rate was 60 ± 9 bpm. Mean effective dose was 13.5 ± 4.6 mSv. When comparing FBP- and TRIM reconstructed series, the attenuation within the ascending aorta (392 ± 70.7 vs. 396.8 ± 70.1 HU, p > 0.05) and CNR (13.2 ± 3.2 vs. 11.7 ± 3.1, p > 0.05) were not significantly different. A total of 110 coronary segments were evaluated. All studies were deemed diagnostic; however, there was a significant (p < 0.05) difference in the severity score distribution of coronary motion artifacts between FBP (median = 2.5) and TRIM (median = 2.0) reconstructions. Conclusion: The algorithm evaluated here delivers diagnostic imaging quality of the coronary arteries despite 500 ms gantry rotation. Possible applications include improvement of cardiac imaging on slower gantry rotation systems or mitigation of the trade-off between temporal resolution and CNR in obese patients.

  20. CT venography for deep venous thrombosis: continuous images versus reformatted discontinuous images using PIOPED II data.

    Science.gov (United States)

    Goodman, Lawrence R; Stein, Paul D; Beemath, Afzal; Sostman, H Dirk; Wakefield, Thomas W; Woodard, Pamela K; Yankelevitz, David F

    2007-08-01

    This study was designed to determine whether discontinuous CT of the lower extremities for the detection of deep venous thrombosis (DVT) yields results similar to those of complete helical imaging using cases from the Prospective Investigation of Pulmonary Embolism Diagnosis II (PIOPED II). In PIOPED II, CT venography followed CT angiography (CTA) to detect pulmonary embolus, using 7.5-mm continuous helical imaging from the iliac crest to the tibial plateau. DVT was detected in 105 of 737 patients (14.2%). We randomly chose 54 positive cases and 96 negative cases for our study. The continuous helical images were reformatted as 7.5-mm images and two of every three images were deleted. These images (7.5 mm; skip = 15 mm) were then sent--without identifying information--to the original reviewers. From 1 to 3.5 years had elapsed since the original interpretations. The results of the new interpretations were compared with the original CT venography consensus interpretations of PIOPED II. There was agreement for the presence of DVT in at least one leg (same leg) or for the absence of DVT in both legs in 133 of the 150 study patients (89%). The kappa statistic showed substantial agreement between the consensus interpretations and the test interpretations (kappa = 0.75; 95% CI = 0.64-0.86) per patient. There was good--but not perfect--agreement between continuous helical and discontinuous axial imaging for the detection of DVT. Given the vagaries of interobserver and intraobserver variation, there appears to be little difference between the two approaches. Adopting discontinuous imaging and other dose-reduction strategies can reduce pelvic radiation by more than 75%.

  1. A detection model of underwater topography with a series of SAR images acquired at different time

    Institute of Scientific and Technical Information of China (English)

    YANG Jungang; ZHANG Jie; MENG Junmin

    2010-01-01

    underwater topography is one of oceanic features detected by Synthetic Aperture Radar. Under-water topography SAR imaging mechanism shows that tidal current is the important factor for underwater topography SAR imaging. Thus under the same wind field condition, SAR images for the same area acquired at different time include different information of the underwater topogra-phy. To utilize synchronously SAR images acquired at different time for the underwater topography SAR detection and improve the precision of detection, based on the detection model of underwater topography with single SAR image and the periodicity of tidal current, a detection model of under- water topography with a series of SAR images acquired at different time is developed by combing with tide and tidal current numerical simulation. To testify the feasibility of the presented model, Taiwan Shoal located at the south outlet of Taiwan Strait is selected as study area and three SAR images are used in the underwater topography detection. The detection results are compared with the field observation data of water depth carried out by R/V Dongfanghong 2, and the errors of the detection are compared with those of the single SAR image. All comparisons show that the detec- tion model presented in the paper improves the precision of underwater topography SAR detection, and the presented model is feasible.

  2. CT image quality in sinogram affirmed iterative reconstruction phantom study - is there a point of diminishing returns?

    Energy Technology Data Exchange (ETDEWEB)

    Infante, Juan C. [University of Miami, Department of Radiology, Miami, FL (United States); Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging, Chicago, IL (United States); Liu, Yu [Medical College of Wisconsin, Department of Radiology, Milwaukee, WI (United States); Rigsby, Cynthia K. [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging, Chicago, IL (United States); Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States); Northwestern University Feinberg School of Medicine, Department of Pediatrics, Chicago, IL (United States)

    2017-03-15

    In our pediatric practice, we have observed qualitatively limited improvement in the image quality of images generated with sinogram affirmed iterative reconstruction (SAFIRE) compared to series generated with filtered back projection (FBP), particularly in cases near or below a CT dose index volume (CTDI{sub vol}) of 1-mGy. To determine whether the image quality advantage of SAFIRE remains constant across clinically used CT dose levels in an American College of Radiology (ACR) CT accreditation phantom including the lower dose range used in pediatric imaging. An exemption from institutional review board approval was obtained for this phantom-based study. An ACR quality phantom was scanned in incremental kV steps and effective tube current intervals. Acquisitions were reconstructed with FBP and SAFIRE strengths of 1, 3 and 5. Image quality measures were calculated including signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), low-contrast resolution and high-contrast resolution. Peak SNR was also calculated. Descriptive and nonparametric statistics were used to compare these image quality metrics while normalizing to CT dose index (CTDI). The percent improvement in SNR and peak SNR of SAFIRE reconstructions compared to FBP decreased from about 70% for image sets acquired above a 1.42 mGy CTDI to 25% at a 0.25 mGy CTDI. CNR improvement with SAFIRE did not vary with dose. No significant difference was seen in the low-contrast resolution or high-contrast resolution of SAFIRE images compared to FBP. SNR did not improve equally after applying SAFIRE across a spectrum clinically used CTDIs. Below a threshold CTDI, the incremental improvement of SAFIRE compared to FBP decreased. (orig.)

  3. A novel stereoscopic projection display system for CT images of fractures.

    Science.gov (United States)

    Liu, Xiujuan; Jiang, Hong; Lang, Yuedong; Wang, Hongbo; Sun, Na

    2013-06-01

    The present study proposed a novel projection display system based on a virtual reality enhancement environment. The proposed system displays stereoscopic images of fractures and enhances the computed tomography (CT) images. The diagnosis and treatment of fractures primarily depend on the post-processing of CT images. However, two-dimensional (2D) images do not show overlapping structures in fractures since they are displayed without visual depth and these structures are too small to be simultaneously observed by a group of clinicians. Stereoscopic displays may solve this problem and allow clinicians to obtain more information from CT images. Hardware with which to generate stereoscopic images was designed. This system utilized the conventional equipment found in meeting rooms. The off-axis algorithm was adopted to convert the CT images into stereo image pairs, which were used as the input for a stereo generator. The final stereoscopic images were displayed using a projection system. Several CT fracture images were imported into the system for comparison with traditional 2D CT images. The results showed that the proposed system aids clinicians in group discussions by producing large stereoscopic images. The results demonstrated that the enhanced stereoscopic CT images generated by the system appear clearer and smoother, such that the sizes, displacement and shapes of bone fragments are easier to assess. Certain fractures that were previously not visible on 2D CT images due to vision overlap became vividly evident in the stereo images. The proposed projection display system efficiently, economically and accurately displayed three-dimensional (3D) CT images. The system may help clinicians improve the diagnosis and treatment of fractures.

  4. 千伏级 CBCT 图像 CT 值校正及在放疗剂量计算中应用%Investigation of CT numbers correction of kilo-voltage cone-beam CT images for accurate dose calculation

    Institute of Scientific and Technical Information of China (English)

    王雪桃; 柏森; 李光俊; 蒋晓芹; 苏晨; 李衍龙; 朱智慧

    2015-01-01

    目的:研究千伏级CBCT图像CT值校正方法,提高其用于剂量计算的准确性。方法以扇形束计划 CT 作为先验信息,将 CBCT 与计划 CT 图像进行刚性配准,通过将 CBCT 与计划 CT 图像相减得到 CBCT 散射背景估计,对散射背景进行低通滤波处理,最后将原始 CBCT 图像减去滤波后的散射背景得到校正的 CBCT 图像。对 Catphan600模体和4例盆腔恶性肿瘤患者的 CBCT 图像进行校正,配对 t 检验校正前后 CBCT 与计划 CT 的差异,评估校正后的 CBCT 图像质量并分析用于剂量计算的准确性。结果经 CT 值校正后 CBCT 图像伪影明显减少,空气、脂肪、肌肉、股骨头的平均值校正前与计划 CT 分别相差232、89、29、66 HU,而校正后平均值差别缩小至5 HU 内(P=0??39、0??66、0??59、1??00)。校正后 CBCT 图像用于剂量计算误差在2%内。结论校正后的 CBCT 图像 CT 值与计划 CTCT 值相似,用于剂量计算可得到准确的结果。%Objective To study CT numbers correction of kilo?voltage cone?beam CT (KV?CBCT) images for dose calculation. Method Aligning the CBCT images with plan CT images, then obtain the background scatter by subtracting CT images from CBCT images. The background scatter is then processed by low?pass filter. The final CBCT images are acquired by subtracting the background scatter from the raw CBCT. KV?CBCT images of Catphan600 phantom and four patients with pelvic tumors were obtained with the linac?integrated CBCT system. The CBCT images were modified to correct the CT numbers. Finally, compare HU numbers between corrected CBCT and planning CT by paired T test. Evaluate the image quality and accuracy of dose calculation of the modified CBCT images. Results The proposed method reduces the artifacts of CBCT images significantly. The differences of CT numbers were 232 HU, 89 HU, 29 HU and 66 HU for air, fat, muscle and femoral head between CT and CBCT

  5. Segmentation of the thoracic aorta in noncontrast cardiac CT images.

    Science.gov (United States)

    Avila-Montes, Olga C; Kurkure, Uday; Nakazato, Ryo; Berman, Daniel S; Dey, Damini; Kakadiaris, Ioannis A

    2013-09-01

    Studies have shown that aortic calcification is associated with cardiovascular disease. In this study, a method for localization, centerline extraction, and segmentation of the thoracic aorta in noncontrast cardiac-computed tomography (CT) images, toward the detection of aortic calcification, is presented. The localization of the right coronary artery ostium slice is formulated as a regression problem whose input variables are obtained from simple intensity features computed from a pyramid representation of the slice. The localization, centerline extraction, and segmentation of the aorta are formulated as optimal path detection problems. Dynamic programming is applied in the Hough space for localizing key center points in the aorta which guide the centerline tracing using a fast marching-based minimal path extraction framework. The input volume is then resampled into a stack of 2-D cross-sectional planes orthogonal to the obtained centerline. Dynamic programming is again applied for the segmentation of the aorta in each slice of the resampled volume. The obtained segmentation is finally mapped back to its original volume space. The performance of the proposed method was assessed on cardiac noncontrast CT scans and promising results were obtained.

  6. Sinusitis and intracranial sepsis: the CT imaging and clinical presentation

    Energy Technology Data Exchange (ETDEWEB)

    Saxton, V.J. [Dept. of Radiology, Royal Children`s Hospital, Melbourne (Australia); Boldt, D.W. [Dept. of Radiology, Royal Children`s Hospital, Melbourne (Australia); Shield, L.K. [Dept. of Neurology, Royal Children`s Hospital, Melbourne (Australia)

    1995-11-01

    The CT imaging and clinical presentation in 14 children with coexistent intracranial sepsis and sinusitis were reviewed. A routine CT head scan (10-mm thick semi-axial slices through the cranium done before and after intravenous contrast medium administration) was found to be an inadequate initial investigation as the intracranial collection was missed in four patients and the abnormal sinuses not shown in six. In half the children the dagnosis of sinusitis was unsuspected at the time of admission. The dominant clinical features were fever, intense headache and facial swelling in early adolescent males. In this clinical setting we recommend: (1) The routine scan is extended through the frontal and ethmoidal sinuses and photographed at a window level and width showing both bone detail and air/soft tissue interfaces; (2) direct coronal projections are performed through the anterior cranial fossa if no collection is seen on the routine study; (3) an early repeat scan within 48 h if the initial study shows no intracranial pathology but the fronto-ethomoidal sinuses are abnormal and there is a high clinical supicion of intracranial sepsis; and (4) in the presence of intracranial sepsis the vault is viewed at bone window settings to exclude cranial osteomyelitis. (orig.)

  7. Impact of image denoising on image quality, quantitative parameters and sensitivity of ultra-low-dose volume perfusion CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Ahmed E. [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Radiology, Tuebingen (Germany); Brockmann, Carolin; Afat, Saif; Pjontek, Rastislav; Nikoubashman, Omid; Brockmann, Marc A.; Wiesmann, Martin [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Yang, Zepa; Kim, Changwon [Seoul National University, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Suwon (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Nikolaou, Konstantin [Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Radiology, Tuebingen (Germany); Kim, Jong Hyo [Seoul National University, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Suwon (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Advanced Institute of Convergence Technology, Center for Medical-IT Convergence Technology Research, Suwon (Korea, Republic of); Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of)

    2016-01-15

    To examine the impact of denoising on ultra-low-dose volume perfusion CT (ULD-VPCT) imaging in acute stroke. Simulated ULD-VPCT data sets at 20 % dose rate were generated from perfusion data sets of 20 patients with suspected ischemic stroke acquired at 80 kVp/180 mAs. Four data sets were generated from each ULD-VPCT data set: not-denoised (ND); denoised using spatiotemporal filter (D1); denoised using quanta-stream diffusion technique (D2); combination of both methods (D1 + D2). Signal-to-noise ratio (SNR) was measured in the resulting 100 data sets. Image quality, presence/absence of ischemic lesions, CBV and CBF scores according to a modified ASPECTS score were assessed by two blinded readers. SNR and qualitative scores were highest for D1 + D2 and lowest for ND (all p ≤ 0.001). In 25 % of the patients, ND maps were not assessable and therefore excluded from further analyses. Compared to original data sets, in D2 and D1 + D2, readers correctly identified all patients with ischemic lesions (sensitivity 1.0, kappa 1.0). Lesion size was most accurately estimated for D1 + D2 with a sensitivity of 1.0 (CBV) and 0.94 (CBF) and an inter-rater agreement of 1.0 and 0.92, respectively. An appropriate combination of denoising techniques applied in ULD-VPCT produces diagnostically sufficient perfusion maps at substantially reduced dose rates as low as 20 % of the normal scan. (orig.)

  8. SU-E-J-222: Evaluation of Deformable Registration of PET/CT Images for Cervical Cancer Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Y; Turian, J; Templeton, A; Kiel, K; Chu, J [Rush University Medical Center, Chicago, IL (United States); Kadir, T [Mirada Medical Ltd., Oxford, Oxfordshire (United Kingdom)

    2014-06-01

    Purpose: PET/CT provides important functional information for radiotherapy targeting of cervical cancer. However, repeated PET/CT procedures for external beam and subsequent brachytherapy expose patients to additional radiation and are not cost effective. Our goal is to investigate the possibility of propagating PET-active volumes for brachytherapy procedures through deformable image registration (DIR) of earlier PET/CT and ultimately to minimize the number of PET/CT image sessions required. Methods: Nine cervical cancer patients each received their brachytherapy preplanning PET/CT at the end of EBRT with a Syed template in place. The planning PET/CT was acquired on the day of brachytherapy treatment with the actual applicator (Syed or Tandem and Ring) and rigidly registered. The PET/CT images were then deformably registered creating a third (deformed) image set for target prediction. Regions of interest with standardized uptake values (SUV) greater than 65% of maximum SUV were contoured as target volumes in all three sets of PET images. The predictive value of the registered images was evaluated by comparing the preplanning and deformed PET volumes with the planning PET volume using Dice's coefficient (DC) and center-of-mass (COM) displacement. Results: The average DCs were 0.12±0.14 and 0.19±0.16 for rigid and deformable predicted target volumes, respectively. The average COM displacements were 1.9±0.9 cm and 1.7±0.7 cm for rigid and deformable registration, respectively. The DCs were improved by deformable registration, however, both were lower than published data for DIR in other modalities and clinical sites. Anatomical changes caused by different brachytherapy applicators could have posed a challenge to the DIR algorithm. The physiological change from interstitial needle placement may also contribute to lower DC. Conclusion: The clinical use of DIR in PET/CT for cervical cancer brachytherapy appears to be limited by applicator choice and requires

  9. CT, MRI, and FDG-PET/CT imaging findings of abdominopelvic desmoplastic small round cell tumors: Correlation with histopathologic findings

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Weidong, E-mail: dongw.z@163.com [State Key Laboratory of Oncology in South China, 651 Dongfengdong Road, Guangzhou, Guangdong 510060 (China) and Department of Radiology, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060 (China); Li Chuanxing, E-mail: lichuanh@mail.sysu.edu.cn [State Key Laboratory of Oncology in South China, 651 Dongfengdong Road, Guangzhou, Guangdong 510060 (China); Department of Radiology, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060 (China); Liu Qingyu, E-mail: liu.qingyu@163.com [Department of Radiology, No. 2 Affiliated Hospital, 107 Yanjiangxi Road, Sun Yat-sen University, Guangzhou, Guangdong 510120 (China); Hu Yingying, E-mail: yingyinghu1981@163.com [State Key Laboratory of Oncology in South China, 651 Dongfengdong Road, Guangzhou, Guangdong 510060 (China) and Department of Radiology, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060 (China); Cao Yun, E-mail: caoyun@mail.sysu.edu.cn [State Key Laboratory of Oncology in South China, 651 Dongfengdong Road, Guangzhou, Guangdong 510060 (China); Department of Pathology, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060 (China); Huang Jinhua, E-mail: drhuangjh@163.com [State Key Laboratory of Oncology in South China, 651 Dongfengdong Road, Guangzhou, Guangdong 510060 (China) and Department of Radiology, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060 (China)

    2011-11-15

    Objective: To analyze computed tomography (CT), magnetic resonance imaging (MRI), and fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT imaging features of abdominopelvic desmoplastic small round cell tumor (DSRCT) and to improve the diagnostic efficacy of these techniques for the detection of such tumor. Methods: We retrospectively analyzed 7 cases of abdominopelvic DSRCT confirmed by histopathologic analysis. Among the 7 patients, 5 patients had undergone CT scanning, 2 of which were also examined with FDG-PET/CT imaging, and 2 had undergone MRI. Unenhanced and contrast-enhanced examinations were performed in all patients, and 2 patients had also undergone dynamic CT contrast-enhanced examinations. Image characteristics, such as shape, size, number, edge, attenuation, and intensity of each lesion before and after contrast enhancement were analyzed and compared with the pathomorphology of the tumors. Results: Multiple large masses in the abdominopelvis were detected in 6 cases, and a large mass in the pelvis was detected in 1 case. Six cases showed largest mass in pelvis, and 1 case in mesentery. None of the masses had a definite organ origin. CT showed soft tissue masses with patchy foci of hypodense areas. MR T1-weighted images revealed lesions with mild hypointense areas and patchy hypointense areas in 2 cases and lesions with patchy hyperintense areas in 1 case. T2-weighted images showed lesions with mixed isointense and hyperintense areas in 1 case and lesions with mixed hypointense, isointense, and hyperintense areas in another. Contrast-enhanced CT and T1-weighted images showed mildly heterogeneous enhancement of the lesions. Other associated findings included peritoneal seeding (n = 3), peritoneal effusions (n = 3), hepatic metastasis (n = 2), bone metastasis (n = 1), and mesenteric and retroperitoneal lymphadenopathy (n = 4). FDG-PET/CT showed multiple nodular foci of increased metabolic activity in the abdominopelvic masses, in the hepatic and

  10. Improving abdomen tumor low-dose CT images using a fast dictionary learning based processing

    Science.gov (United States)

    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.

  11. Patient satisfaction with coronary CT angiography, myocardial CT perfusion, myocardial perfusion MRI, SPECT myocardial perfusion imaging and conventional coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Feger, S.; Rief, M.; Zimmermann, E.; Richter, F.; Roehle, R. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Dewey, M. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Institut fuer Radiologie, Berlin (Germany); Schoenenberger, E. [Medizinische Hochschule Hannover, Department of Medicine, Hannover (Germany)

    2015-07-15

    To evaluate patient acceptance of noninvasive imaging tests for detection of coronary artery disease (CAD), including single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), stress perfusion magnetic resonance imaging (MRI), coronary CT angiography (CTA) in combination with CT myocardial stress perfusion (CTP), and conventional coronary angiography (CCA). Intraindividual comparison of perception of 48 patients from the CORE320 multicentre multinational study who underwent rest and stress SPECT-MPI with a technetium-based tracer, combined CTA and CTP (both with contrast agent, CTP with adenosine), MRI, and CCA. The analysis was performed by using a validated questionnaire. Patients had significantly more concern prior to CCA than before CTA/CTP (p < 0.001). CTA/CTP was also rated as more comfortable than SPECT-MPI (p = 0.001). Overall satisfaction with CT was superior to that of MRI (p = 0.007). More patients preferred CT (46 %; p < 0.001) as a future diagnostic test. Regarding combined CTA/CTP, CTP was characterised by higher pain levels and an increased frequency of angina pectoris during the examination (p < 0.001). Subgroup analysis showed a higher degree of pain during SPECT-MPI with adenosine stress compared to physical exercise (p = 0.016). All noninvasive cardiac imaging tests are well accepted by patients, with CT being the preferred examination. (orig.)

  12. Alpha image reconstruction (AIR): A new iterative CT image reconstruction approach using voxel-wise alpha blending

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Christian [Institute of Medical Physics, Friedrich-Alexander University (FAU), Erlangen 91052 (Germany); Sawall, Stefan; Knaup, Michael [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg 69120 (Germany); Kachelrieß, Marc, E-mail: marc.kachelriess@dkfz-heidelberg [Institute of Medical Physics, Friedrich-Alexander University (FAU), Erlangen 91052, Germany and Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg 69120 (Germany)

    2014-06-15

    factor for contrast-resolution plots. Furthermore, the authors calculate the contrast-to-noise ratio with the low contrast disks and the authors compare the agreement of the reconstructions with the ground truth by calculating the normalized cross-correlation and the root-mean-square deviation. To evaluate the clinical performance of the proposed method, the authors reconstruct patient data acquired with a Somatom Definition Flash dual source CT scanner (Siemens Healthcare, Forchheim, Germany). Results: The results of the simulation study show that among the compared algorithms AIR achieves the highest resolution and the highest agreement with the ground truth. Compared to the reference FBP reconstruction AIR is able to reduce the relative pixel noise by up to 50% and at the same time achieve a higher resolution by maintaining the edge information from the basis images. These results can be confirmed with the patient data. Conclusions: To evaluate the AIR algorithm simulated and measured patient data of a state-of-the-art clinical CT system were processed. It is shown, that generating CT images through the reconstruction of weighting coefficients has the potential to improve the resolution noise trade-off and thus to improve the dose usage in clinical CT.

  13. TU-EF-204-02: Hiigh Quality and Sub-MSv Cerebral CT Perfusion Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ke; Niu, Kai; Wu, Yijing; Chen, Guang-Hong [University of Wisconsin, Madison, WI (United States)

    2015-06-15

    Purpose: CT Perfusion (CTP) imaging is of great importance in acute ischemic stroke management due to its potential to detect hypoperfused yet salvageable tissue and distinguish it from definitely unsalvageable tissue. However, current CTP imaging suffers from poor image quality and high radiation dose (up to 5 mSv). The purpose of this work was to demonstrate that technical innovations such as Prior Image Constrained Compressed Sensing (PICCS) have the potential to address these challenges and achieve high quality and sub-mSv CTP imaging. Methods: (1) A spatial-temporal 4D cascaded system model was developed to indentify the bottlenecks in the current CTP technology; (2) A task-based framework was developed to optimize the CTP system parameters; (3) Guided by (1) and (2), PICCS was customized for the reconstruction of CTP source images. Digital anthropomorphic perfusion phantoms, animal studies, and preliminary human subject studies were used to validate and evaluate the potentials of using these innovations to advance the CTP technology. Results: The 4D cascaded model was validated in both phantom and canine stroke models. Based upon this cascaded model, it has been discovered that, as long as the spatial resolution and noise properties of the 4D source CT images are given, the 3D MTF and NPS of the final CTP maps can be analytically derived for a given set of processing methods and parameters. The cascaded model analysis also identified that the most critical technical factor in CTP is how to acquire and reconstruct high quality source images; it has very little to do with the denoising techniques often used after parametric perfusion calculations. This explained why PICCS resulted in a five-fold dose reduction or substantial improvement in image quality. Conclusion: Technical innovations generated promising results towards achieving high quality and sub-mSv CTP imaging for reliable and safe assessment of acute ischemic strokes. K. Li, K. Niu, Y. Wu: Nothing to

  14. Pulmonary Vascular Tree Segmentation from Contrast-Enhanced CT Images

    CERN Document Server

    Helmberger, M; Pienn, M; Balint, Z; Olschewski, A; Bischof, H

    2013-01-01

    We present a pulmonary vessel segmentation algorithm, which is fast, fully automatic and robust. It uses a coarse segmentation of the airway tree and a left and right lung labeled volume to restrict a vessel enhancement filter, based on an offset medialness function, to the lungs. We show the application of our algorithm on contrast-enhanced CT images, where we derive a clinical parameter to detect pulmonary hypertension (PH) in patients. Results on a dataset of 24 patients show that quantitative indices derived from the segmentation are applicable to distinguish patients with and without PH. Further work-in-progress results are shown on the VESSEL12 challenge dataset, which is composed of non-contrast-enhanced scans, where we range in the midfield of participating contestants.

  15. Dynamic CT perfusion imaging of the myocardium: a technical note on improvement of image quality.

    Directory of Open Access Journals (Sweden)

    Daniela Muenzel

    Full Text Available OBJECTIVE: To improve image and diagnostic quality in dynamic CT myocardial perfusion imaging (MPI by using motion compensation and a spatio-temporal filter. METHODS: Dynamic CT MPI was performed using a 256-slice multidetector computed tomography scanner (MDCT. Data from two different patients-with and without myocardial perfusion defects-were evaluated to illustrate potential improvements for MPI (institutional review board approved. Three datasets for each patient were generated: (i original data (ii motion compensated data and (iii motion compensated data with spatio-temporal filtering performed. In addition to the visual assessment of the tomographic slices, noise and contrast-to-noise-ratio (CNR were measured for all data. Perfusion analysis was performed using time-density curves with regions-of-interest (ROI placed in normal and hypoperfused myocardium. Precision in definition of normal and hypoperfused areas was determined in corresponding coloured perfusion maps. RESULTS: The use of motion compensation followed by spatio-temporal filtering resulted in better alignment of the cardiac volumes over time leading to a more consistent perfusion quantification and improved detection of the extend of perfusion defects. Additionally image noise was reduced by 78.5%, with CNR improvements by a factor of 4.7. The average effective radiation dose estimate was 7.1±1.1 mSv. CONCLUSION: The use of motion compensation and spatio-temporal smoothing will result in improved quantification of dynamic CT MPI using a latest generation CT scanner.

  16. Surgical stent for dental implant using cone beam CT images

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hyung Soo; Kim, Gyu Tae; Choi, Yong Suk; Hwang, Eui Hwan [Department of Oral and Maxillofacial Radiology, School of Dentistry, Kung Hee University, Seoul (Korea, Republic of)

    2010-12-15

    The purpose of this study is to develop a surgical stent for dental implant procedure that can be easily applied and affordable by using cone beam computerized tomography (CBCT). Aluminum, Teflon-PFA (perfluoroalkoxy), and acetal (polyoxymethylene plastic) were selected as materials for the surgical stent. Among these three materials, the appropriate material was chosen using the CBCT images. The surgical stent, which could be easily placed into an oral cavity, was designed with chosen material. CBCT images of the new surgical stent on mandible were obtained using Alphard-3030 dental CT system (Asahi Roentgen Co., Ltd., Kyoto, Japan). The point of insertion was prescribed on the surgical stent with the multiplanar reconstruction software of OnDemand3D (CyberMed Inc., Seoul, Korea). Guide holes were made at the point of insertion on the surgical stent using newly designed guide jig. CBCT scans was taken for the second time to verify the accuracy of the newly designed surgical stent. Teflon-PFA showed radiologically excellent image characteristics for the surgical stent. High accuracy and reproducibility of implantation were confirmed with the surgical stent. The newly designed surgical stent can lead to the accurate implantation and achieve the clinically predictable result.

  17. Accessory cardiac bronchus: Proposed imaging classification on multidetector CT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kang Min; Kim, Young Tong; Han, Jong Kyu; Jou, Sung Shick [Dept. of Radiology, Soonchunhyang University College of Medicine, Cheonan Hospital, Cheonan (Korea, Republic of)

    2016-02-15

    To propose the classification of accessory cardiac bronchus (ACB) based on imaging using multidetector computed tomography (MDCT), and evaluate follow-up changes of ACB. This study included 58 patients diagnosed as ACB since 9 years, using MDCT. We analyzed the types, division locations and division directions of ACB, and also evaluated changes on follow-up. We identified two main types of ACB: blind-end (51.7%) and lobule (48.3%). The blind-end ACB was further classified into three subtypes: blunt (70%), pointy (23.3%) and saccular (6.7%). The lobule ACB was also further classified into three subtypes: complete (46.4%), incomplete (28.6%) and rudimentary (25%). Division location to the upper half bronchus intermedius (79.3%) and medial direction (60.3%) were the most common in all patients. The difference in division direction was statistically significant between the blind-end and lobule types (p = 0.019). Peribronchial soft tissue was found in five cases. One calcification case was identified in the lobule type. During follow-up, ACB had disappeared in two cases of the blind-end type and in one case of the rudimentary subtype. The proposed classification of ACB based on imaging, and the follow-up CT, helped us to understand the various imaging features of ACB.

  18. CT imaging of splenic sequestration in sickle cell disease

    Energy Technology Data Exchange (ETDEWEB)

    Sheth, S.; Piomelli, S. [Columbia Univ., New York, NY (United States). Dept. of Pediatrics; Ruzal-Shapiro, C.; Berdon, W.E. [Columbia Univ., New York, NY (United States). Div. of Pediatric Radiology

    2000-12-01

    Pooling of blood in the spleen is a frequent occurrence in children with sickle cell diseases, particularly in the first few years of life, resulting in what is termed ''splenic sequestration crisis.'' The spectrum of severity in this syndrome is wide, ranging from mild splenomegaly to massive enlargement, circulatory collapse, and even death. The diagnosis is usually clinical, based on the enlargement of the spleen with a drop in hemoglobin level by >2 g/dl, and it is rare that imaging studies are ordered. However, in the patient who presents to the emergency department with non-specific findings of an acute abdomen, it is important to recognize the appearance of sequestration on imaging studies. We studied seven patients utilizing contrast-enhanced CT scans and found two distinct patterns - multiple, peripheral, non-enhancing low-density areas or large, diffuse areas of low density in the majority of the splenic tissue. Although radiological imaging is not always necessary to diagnose splenic sequestration, in those situations where this diagnosis is not immediately obvious, it makes an important clarifying contribution. (orig.)

  19. CT imaging, then and now: a 30-year review of the economics of computed tomography.

    Science.gov (United States)

    Stockburger, Wayne T

    2004-01-01

    The first computed tomography (CT) scanner in the US was installed in June 1973 at the Mayo Clinic in Rochester, MN. By the end of 1974, 44 similar systems had been installed at medical facilities around the country. Less than 4 years after the introduction of CT imaging in the US, at least 400 CT systems had been installed. The practice of pneumoencephalography was eliminated. The use of nuclear medicine brain scans significantly diminished. At the time, CT imaging was limited to head studies, but with the introduction of contrast agents and full body CT systems the changes in the practice of medicine became even more significant. CT imaging was hailed by the US medical community as the greatest advance in radiology since the discovery of x-rays. But the rapid spread of CT systems, their frequency of use, and the associated increase in healthcare costs combined to draw the attention of decision-makers within the federal and state governments, specifically to establish policies regarding the acquisition and use of diagnostic technologies. Initially, CT imaging was limited to neurological applications, but in the 30 years since its inception, capabilities and applications have been expanded as a result of the advancements in technology and software development. While neurological disorders are still a common reason for CT imaging, many other medical disciplines (oncology, emergency medicine, orthopedics, etc.) have found CT imaging to be the definitive tool for diagnostic information. As such, the clinical demand for CT imaging has steadily increased. Economically, the development of CT imaging has been one of success, even in the face of governmental action to restrict its acquisition and utilization by healthcare facilities. CTimaging has increased the cost of healthcare, but in turn has added unquantifiable value to the practice of medicine in the US.

  20. {sup 18}F-FDG PET/CT imaging factors that predict ischaemic stroke in cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jahae; Song, Ho-Chun [Chonnam National University Hospital, Department of Nuclear Medicine, Gwangju (Korea, Republic of); Choi, Kang-Ho [Chonnam National University Hospital, Cerebrovascular Center, Gwangju (Korea, Republic of); Chonnam National University Hwasun Hospital, Department of Neurology, Hwasun-gun, Jeollanam-do (Korea, Republic of); Kim, Joon-Tae; Park, Man-Seok; Cho, Ki-Hyun [Chonnam National University Hospital, Cerebrovascular Center, Gwangju (Korea, Republic of)

    2016-11-15

    {sup 18}F-FDG PET/CT can acquire both anatomical and functional images in a single session. We investigated which factors of {sup 18}F-FDG PET/CT imaging have potential as biomarkers for an increased risk of ischaemic stroke in cancer patients. From among cancer patients presenting with various neurological symptoms and hemiparesis, 134 were selected as eligible for this retrospective analysis. A new infarct lesion on brain MRI within 1 year of FDG PET/CT defined future ischaemic stroke. The target-to-background ratio (TBR) of each arterial segment was used to define arterial inflammation on PET imaging. Abdominal obesity was defined in terms of the area and proportion of visceral adipose tissue (VAT), subcutaneous adipose tissue and total adipose tissue (TAT) on a single CT slice at the umbilical level. Ischaemic stroke confirmed by MRI occurred in 30 patients. Patients with stroke had higher TBRs in the carotid arteries and abdominal aorta (P < 0.001) and a higher VAT proportion (P = 0.021) and TAT proportion (P = 0.041) than patients without stroke. Multiple logistic regression analysis showed that TBRs of the carotid arteries and abdominal aorta, VAT and TAT proportions, and the presence of a metabolically active tumour were significantly associated with future ischaemic stroke. Combining PET and CT variables improved the power for predicting future ischaemic stroke. Our findings suggest that arterial FDG uptake and hypermetabolic malignancy on PET and the VAT proportion on CT could be independent predictors of future ischaemic stroke in patients with cancer and could identify those patients who would benefit from medical treatment. (orig.)

  1. Application of Simulated Three Dimensional CT Image in Orthognathic Surgery

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Don; Park, Chang Seo [Dept. of Dental Radiology, College of Dentistry, Yensei University, Seoul (Korea, Republic of); Yoo, Sun Kook; Lee, Kyoung Sang [Dept. of Medical Engineering, College of Medicine, Yensei University, Seoul (Korea, Republic of)

    1998-08-15

    In orthodontics and orthognathic surgery, cephalogram has been routine practice in diagnosis and treatment evaluation of craniofacial deformity. But its inherent distortion of actual length and angles during projecting three dimensional object to two dimensional plane might cause errors in quantitative analysis of shape and size. Therefore, it is desirable that three dimensional object is diagnosed and evaluated three dimensionally and three dimensional CT image is best for three dimensional analysis. Development of clinic necessitates evaluation of result of treatment and comparison before and after surgery. It is desirable that patient that was diagnosed and planned by three dimensional computed tomography before surgery is evaluated by three dimensional computed tomography after surgery, too. But Because there is no standardized normal values in three dimension now and three dimensional Computed Tomography needs expensive equipment and because of its expenses and amount of exposure to radiation, limitations still remain to be solved in its application to routine practice. If postoperative three dimensional image is constructed by pre and postoperative lateral and postero-anterior cephalograms and preoperative three dimensional computed tomogram, pre and postoperative image will be compared and evaluated three dimensionally without three dimensional computed tomography after surgery and that will contribute to standardize normal values in three dimension. This study introduced new method that computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms, and for validation of new method, in four cases of dry skull that position of mandible was displaced and four patients of orthognathic surgery, computer-simulated three dimensional image and actual postoperative three dimensional image were compared. The results were as follows. 1. In four cases of

  2. Lung Motion Model Validation Experiments, Free-Breathing Tissue Densitometry, and Ventilation Mapping using Fast Helical CT Imaging

    Science.gov (United States)

    Dou, Hsiang-Tai

    The uncertainties due to respiratory motion present significant challenges to accurate characterization of cancerous tissues both in terms of imaging and treatment. Currently available clinical lung imaging techniques are subject to inferior image quality and incorrect motion estimation, with consequences that can systematically impact the downstream treatment delivery and outcome. The main objective of this thesis is the development of the techniques of fast helical computed tomography (CT) imaging and deformable image registration for the radiotherapy applications in accurate breathing motion modeling, lung tissue density modeling and ventilation imaging. Fast helical CT scanning was performed on 64-slice CT scanner using the shortest available gantry rotation time and largest pitch value such that scanning of the thorax region amounts to just two seconds, which is less than typical breathing cycle in humans. The scanning was conducted under free breathing condition. Any portion of the lung anatomy undergoing such scanning protocol would be irradiated for only a quarter second, effectively removing any motion induced image artifacts. The resulting CT data were pristine volumetric images that record the lung tissue position and density in a fraction of the breathing cycle. Following our developed protocol, multiple fast helical CT scans were acquired to sample the tissue positions in different breathing states. To measure the tissue displacement, deformable image registration was performed that registers the non-reference images to the reference one. In modeling breathing motion, external breathing surrogate signal was recorded synchronously with the CT image slices. This allowed for the tissue-specific displacement to be modeled as parametrization of the recorded breathing signal using the 5D lung motion model. To assess the accuracy of the motion model in describing tissue position change, the model was used to simulate the original high-pitch helical CT scan

  3. Strategy study of quantification harmonization of SUV in PET/CT images; Estudo da estrategia de harmonizacao da quantificacao do SUV em imagens de PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Andreia Caroline Fischer da Silveira

    2014-07-01

    In clinical practice, PET/CT images are often analyzed qualitatively by visual comparison of tumor lesions and normal tissues uptake; and semi-quantitatively by means of a parameter called SUV (Standardized Uptake Value). To ensure that longitudinal studies acquired on different scanners are interchangeable, and information of quantification is comparable, it is necessary to establish a strategy to harmonize the quantification of SUV. The aim of this study is to evaluate the strategy to harmonize the quantification of PET/CT images, performed with different scanner models and manufacturers. For this purpose, a survey of the technical characteristics of equipment and acquisition protocols of clinical images of different services of PET/CT in the state of Rio Grande do Sul was conducted. For each scanner, the accuracy of SUV quantification, and the Recovery Coefficient (RC) curves were determined, using the reconstruction parameters clinically relevant and available. From these data, harmonized performance specifications among the evaluated scanners were identified, as well as the algorithm that produces, for each one, the most accurate quantification. Finally, the most appropriate reconstruction parameters to harmonize the SUV quantification in each scanner, either regionally or internationally were identified. It was found that the RC values of the analyzed scanners proved to be overestimated by up to 38%, particularly for objects larger than 17mm. These results demonstrate the need for further optimization, through the reconstruction parameters modification, and even the change of the reconstruction algorithm used in each scanner. It was observed that there is a decoupling between the best image for PET/CT qualitative analysis and the best image for quantification studies. Thus, the choice of reconstruction method should be tied to the purpose of the PET/CT study in question, since the same reconstruction algorithm is not adequate, in one scanner, for qualitative

  4. Iterative reconstruction for dual energy CT with an average image-induced nonlocal means regularization

    Science.gov (United States)

    Zhang, Houjin; Zeng, Dong; Lin, Jiahui; Zhang, Hao; Bian, Zhaoying; Huang, Jing; Gao, Yuanyuan; Zhang, Shanli; Zhang, Hua; Feng, Qianjin; Liang, Zhengrong; Chen, Wufan; Ma, Jianhua

    2017-07-01

    Reducing radiation dose in dual energy computed tomography (DECT) is highly desirable but it may lead to excessive noise in the filtered backprojection (FBP) reconstructed DECT images, which can inevitably increase the diagnostic uncertainty. To obtain clinically acceptable DECT images from low-mAs acquisitions, in this work we develop a novel scheme based on measurement of DECT data. In this scheme, inspired by the success of edge-preserving non-local means (NLM) filtering in CT imaging and the intrinsic characteristics underlying DECT images, i.e. global correlation and non-local similarity, an averaged image induced NLM-based (aviNLM) regularization is incorporated into the penalized weighted least-squares (PWLS) framework. Specifically, the presented NLM-based regularization is designed by averaging the acquired DECT images, which takes the image similarity within the two energies into consideration. In addition, the weighted least-squares term takes into account DECT data-dependent variance. For simplicity, the presented scheme was termed as ‘PWLS-aviNLM’. The performance of the presented PWLS-aviNLM algorithm was validated and evaluated on digital phantom, physical phantom and patient data. The extensive experiments validated that the presented PWLS-aviNLM algorithm outperforms the FBP, PWLS-TV and PWLS-NLM algorithms quantitatively. More importantly, it delivers the best qualitative results with the finest details and the fewest noise-induced artifacts, due to the aviNLM regularization learned from DECT images. This study demonstrated the feasibility and efficacy of the presented PWLS-aviNLM algorithm to improve the DECT reconstruction and resulting material decomposition.

  5. Ultra-low dose comprehensive cardiac CT imaging in a patient with acute myocarditis.

    Science.gov (United States)

    Tröbs, Monique; Brand, Michael; Achenbach, Stephan; Marwan, Mohamed

    2014-01-01

    The ability of contrast-enhanced CT to detect "late enhancement" in a fashion similar to magnetic resonance imaging has been previously reported. We report a case of acute myocarditis with coronary CT angiography as well as "late enhancement" imaging with ultra-low effective radiation dose.

  6. Dose reduction assessment in dynamic CT myocardial perfusion imaging in a porcine balloon-induced-ischemia model

    Science.gov (United States)

    Fahmi, Rachid; Eck, Brendan L.; Vembar, Mani; Bezerra, Hiram G.; Wilson, David L.

    2014-03-01

    We investigated the use of an advanced hybrid iterative reconstruction (IR) technique (iDose4, Philips Health- care) for low dose dynamic myocardial CT perfusion (CTP) imaging. A porcine model was created to mimic coronary stenosis through partial occlusion of the left anterior descending (LAD) artery with a balloon catheter. The severity of LAD occlusion was adjusted with FFR measurements. Dynamic CT images were acquired at end-systole (45% R-R) using a multi-detector CT (MDCT) scanner. Various corrections were applied to the acquired scans to reduce motion and imaging artifacts. Absolute myocardial blood flow (MBF) was computed with a deconvolution-based approach using singular value decomposition (SVD). We compared a high and a low dose radiation protocol corresponding to two different tube-voltage/tube-current combinations (80kV p/100mAs and 120kV p/150mAs). The corresponding radiation doses for these protocols are 7.8mSv and 34.3mSV , respectively. The images were reconstructed using conventional FBP and three noise-reduction strengths of the IR method, iDose. Flow contrast-to-noise ratio, CNRf, as obtained from MBF maps, was used to quantitatively evaluate the effect of reconstruction on contrast between normal and ischemic myocardial tissue. Preliminary results showed that the use of iDose to reconstruct low dose images provide better or comparable CNRf to that of high dose images reconstructed with FBP, suggesting significant dose savings. CNRf was improved with the three used levels of iDose compared to FBP for both protocols. When using the entire 4D dynamic sequence for MBF computation, a 77% dose reduction was achieved, while considering only half the scans (i.e., every other heart cycle) allowed even further dose reduction while maintaining relatively higher CNRf.

  7. Precision Agriculture: Using Low-Cost Systems to Acquire Low-Altitude Images.

    Science.gov (United States)

    Ponti, Moacir; Chaves, Arthur A; Jorge, Fabio R; Costa, Gabriel B P; Colturato, Adimara; Branco, Kalinka R L J C

    2016-01-01

    Low cost remote sensing imagery has the potential to make precision farming feasible in developing countries. In this article, the authors describe image acquisition from eucalyptus, bean, and sugarcane crops acquired by low-cost and low-altitude systems. They use different approaches to handle low-altitude images in both the RGB and NIR (near-infrared) bands to estimate and quantify plantation areas.

  8. Technological value of SPECT/CT fusion imaging for the diagnosis of lower gastrointestinal bleeding.

    Science.gov (United States)

    Wang, Z G; Zhang, G X; Hao, S H; Zhang, W W; Zhang, T; Zhang, Z P; Wu, R X

    2015-11-24

    The aim of this study was to assess the clinical value of diagnosing and locating lower gastrointestinal (GI) bleeding using single photon emission computed tomography (SPECT)/computed tomography (CT) fusion imaging with 99mTc labeled red blood cells ((99m)Tc-RBC). Fifty-six patients with suspected lower GI bleeding received a preoperative intravenous injection of (99m)Tc-RBC and each underwent planar, SPECT/CT imaging of the lower abdominal region. The location and path of lower GI bleeding were diagnosed by contrastive analysis of planar and SPECT/CT fusion imaging. Among the 56 patients selected, there were abnormalities in concentrated radionuclide activity with planar imaging in 50 patients and in SPECT/CT fusion imaging in 52 patients. Moreover, bleeding points that were coincident with the surgical results were evident with planar imaging in 31 patients and with SPECT/CT fusion imaging in 48 patients. The diagnostic sensitivity of planar imaging and SPECT/CT fusion imaging were 89.3% (50/56) and 92.9% (52/56), respectively, and the difference was not statistically significant (χ(2) = 0.11, P > 0.05). The corresponding positional accuracy values were 73.8% (31/42) and 92.3% (48/52), and the difference was statistically significant (χ(2) = 4.63, P CT fusion imaging is an effective, simple, and accurate method that can be used for diagnosing and locating lower GI bleeding.

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

    NARCIS (Netherlands)

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

    2016-01-01

    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 targe

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

    NARCIS (Netherlands)

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

    2016-01-01

    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 targe

  11. Image artefact propagation in motion estimation and reconstruction in interventional cardiac C-arm CT.

    Science.gov (United States)

    Müller, K; Maier, A K; Schwemmer, C; Lauritsch, G; De Buck, S; Wielandts, J-Y; Hornegger, J; Fahrig, R

    2014-06-21

    The acquisition of data for cardiac imaging using a C-arm computed tomography system requires several seconds and multiple heartbeats. Hence, incorporation of motion correction in the reconstruction step may improve the resulting image quality. Cardiac motion can be estimated by deformable three-dimensional (3D)/3D registration performed on initial 3D images of different heart phases. This motion information can be used for a motion-compensated reconstruction allowing the use of all acquired data for image reconstruction. However, the result of the registration procedure and hence the estimated deformations are influenced by the quality of the initial 3D images. In this paper, the sensitivity of the 3D/3D registration step to the image quality of the initial images is studied. Different reconstruction algorithms are evaluated for a recently proposed cardiac C-arm CT acquisition protocol. The initial 3D images are all based on retrospective electrocardiogram (ECG)-gated data. ECG-gating of data from a single C-arm rotation provides only a few projections per heart phase for image reconstruction. This view sparsity leads to prominent streak artefacts and a poor signal to noise ratio. Five different initial image reconstructions are evaluated: (1) cone beam filtered-backprojection (FDK), (2) cone beam filtered-backprojection and an additional bilateral filter (FFDK), (3) removal of the shadow of dense objects (catheter, pacing electrode, etc) before reconstruction with a cone beam filtered-backprojection (cathFDK), (4) removal of the shadow of dense objects before reconstruction with a cone beam filtered-backprojection and a bilateral filter (cathFFDK). The last method (5) is an iterative few-view reconstruction (FV), the prior image constrained compressed sensing combined with the improved total variation algorithm. All reconstructions are investigated with respect to the final motion-compensated reconstruction quality. The algorithms were tested on a mathematical

  12. The Experimental Research on the Frameless Registration of DSA/CT Images

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong-feng; LI Wen; ZENG Pei-feng; ZHAO Jun

    2006-01-01

    DSA images show vessels with clarity and CT images show bones distinctly. In this paper, we present an experimental research on the frameless registration of DSA/CT images based on localization algorithm. With four external markers, the vessels and bones in human brain can be integrated. The mean accuracy of simulated experiment is about 2.0 mm. The experiment proved that the 3D images composed cerebral anatomy and vasculature could help neurosurgeons perform accurate diagnosis and make right operation planning.

  13. Technique for bone volume measurement from human femur head samples by classification of micro-CT image histograms

    Directory of Open Access Journals (Sweden)

    Franco Marinozzi

    2013-09-01

    Full Text Available INTRODUCTION: Micro-CT analysis is a powerful technique for a non-invasive evaluation of the morphometric parameters of trabecular bone samples. This elaboration requires a previous binarization of the images. A problem which arises from the binarization process is the partial volume artifact. Voxels at the external surface of the sample can contain both bone and air so thresholding operates an incorrect estimation of volume occupied by the two materials. AIM: The aim of this study is the extraction of bone volumetric information directly from the image histograms, by fitting them with a suitable set of functions. METHODS: Nineteen trabecular bone samples were extracted from femoral heads of eight patients subject to a hip arthroplasty surgery. Trabecular bone samples were acquired using micro-CT Scanner. Hystograms of the acquired images were computed and fitted by Gaussian-like functions accounting for: a gray levels produced by the bone x-ray absorption, b the portions of the image occupied by air and c voxels that contain a mixture of bone and air. This latter contribution can be considered such as an estimation of the partial volume effect. RESULTS: The comparison of the proposed technique to the bone volumes measured by a reference instrument such as by a helium pycnometer show the method as a good way for an accurate bone volume calculation of trabecular bone samples.

  14. In vivo diagnostic imaging using micro-CT: sequential and comparative evaluation of rodent models for hepatic/brain ischemia and stroke.

    Directory of Open Access Journals (Sweden)

    Naoto Hayasaka

    Full Text Available BACKGROUND: There is an increasing need for animal disease models for pathophysiological research and efficient drug screening. However, one of the technical barriers to the effective use of the models is the difficulty of non-invasive and sequential monitoring of the same animals. Micro-CT is a powerful tool for serial diagnostic imaging of animal models. However, soft tissue contrast resolution, particularly in the brain, is insufficient for detailed analysis, unlike the current applications of CT in the clinical arena. We address the soft tissue contrast resolution issue in this report. METHODOLOGY: We performed contrast-enhanced CT (CECT on mouse models of experimental cerebral infarction and hepatic ischemia. Pathological changes in each lesion were quantified for two weeks by measuring the lesion volume or the ratio of high attenuation area (%HAA, indicative of increased vascular permeability. We also compared brain images of stroke rats and ischemic mice acquired with micro-CT to those acquired with 11.7-T micro-MRI. Histopathological analysis was performed to confirm the diagnosis by CECT. PRINCIPAL FINDINGS: In the models of cerebral infarction, vascular permeability was increased from three days through one week after surgical initiation, which was also confirmed by Evans blue dye leakage. Measurement of volume and %HAA of the liver lesions demonstrated differences in the recovery process between mice with distinct genetic backgrounds. Comparison of CT and MR images acquired from the same stroke rats or ischemic mice indicated that accuracy of volumetric measurement, as well as spatial and contrast resolutions of CT images, was comparable to that obtained with MRI. The imaging results were also consistent with the histological data. CONCLUSIONS: This study demonstrates that the CECT scanning method is useful in rodents for both quantitative and qualitative evaluations of pathologic lesions in tissues/organs including the brain, and is

  15. A preliminary study of CT imaging of water in a carnation flower

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, T.M. [Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113 (Japan); Furukawa, J. [Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113 (Japan); Matsubayashi, M. [Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Ibaraki-ken 319-11 (Japan)

    1999-11-03

    We present the trial to determine the water deletion part in a carnation flower tissue while drying by neutron computer tomography (CT). The flower part was fixed on a rotating disk and thermal neutrons were irradiated for 4 s per projection. The total neutron dose was 6.0x10{sup 8} n/cm{sup 2} per projection. The neutrons penetrating the sample were converted to photons by a fluorescence converter. The photon image was guided to a cooled CCD camera using two mirrors. The sample was rotated, stepwise, every 1 deg. , up to 180 deg. , i.e. 180 images were obtained for the CT construction. Horizontal CT images of several slices of the flower were taken before and after the drying treatment. Vertical CT images of the flower were also constructed based on horizontal CT images. It was found that the water around the ovule was selectively removed by the drying treatment.

  16. A preliminary study of CT imaging of water in a carnation flower

    Science.gov (United States)

    Nakanishi, T. M.; Furukawa, J.; Matsubayashi, M.

    1999-11-01

    We present the trial to determine the water deletion part in a carnation flower tissue while drying by neutron computer tomography (CT). The flower part was fixed on a rotating disk and thermal neutrons were irradiated for 4 s per projection. The total neutron dose was 6.0×10 8 n/cm 2 per projection. The neutrons penetrating the sample were converted to photons by a fluorescence converter. The photon image was guided to a cooled CCD camera using two mirrors. The sample was rotated, stepwise, every 1°, up to 180°, i.e. 180 images were obtained for the CT construction. Horizontal CT images of several slices of the flower were taken before and after the drying treatment. Vertical CT images of the flower were also constructed based on horizontal CT images. It was found that the water around the ovule was selectively removed by the drying treatment.

  17. Atlas image labeling of subcortical structures and vascular territories in brain CT images.

    Science.gov (United States)

    Du, Kaifang; Zhang, Li; Nguyen, Tony; Ordy, Vincent; Fichte, Heinz; Ditt, Hendrik; Chefd'hotel, Christophe

    2013-01-01

    We propose a multi-atlas labeling method for subcortical structures and cerebral vascular territories in brain CT images. Each atlas image is registered to the query image by a non-rigid registration and the deformation is then applied to the labeling of the atlas image to obtain the labeling of the query image. Four label fusion strategies (single atlas, most similar atlas, major voting, and STAPLE) were compared. Image similarity values in non-rigid registration were calculated and used to select and rank atlases. Major voting fusion strategy gave the best accuracy, with DSC (Dice similarity coefficient) around 0.85 ± 0.03 for caudate, putamen, and thalamus. The experimental results also show that fusing more atlases does not necessarily yield higher accuracy and we should be able to improve accuracy and decrease computation cost at the same time by selecting a preferred set with the minimum number of atlases.

  18. Investigation of cone-beam CT image quality trade-off for image-guided radiation therapy

    Science.gov (United States)

    Bian, Junguo; Sharp, Gregory C.; Park, Yang-Kyun; Ouyang, Jinsong; Bortfeld, Thomas; El Fakhri, Georges

    2016-05-01

    It is well-known that projections acquired over an angular range slightly over 180° (so-called short scan) are sufficient for fan-beam reconstruction. However, due to practical imaging conditions (projection data and reconstruction image discretization, physical factors, and data noise), the short-scan reconstructions may have different appearances and properties from the full-scan (scans over 360°) reconstructions. Nevertheless, short-scan configurations have been used in applications such as cone-beam CT (CBCT) for head-neck-cancer image-guided radiation therapy (IGRT) that only requires a small field of view due to the potential reduced imaging time and dose. In this work, we studied the image quality trade-off for full, short, and full/short scan configurations with both conventional filtered-backprojection (FBP) reconstruction and iterative reconstruction algorithms based on total-variation (TV) minimization for head-neck-cancer IGRT. Anthropomorphic and Catphan phantoms were scanned at different exposure levels with a clinical scanner used in IGRT. Both visualization- and numerical-metric-based evaluation studies were performed. The results indicate that the optimal exposure level and number of views are in the middle range for both FBP and TV-based iterative algorithms and the optimization is object-dependent and task-dependent. The optimal view numbers decrease with the total exposure levels for both FBP and TV-based algorithms. The results also indicate there are slight differences between FBP and TV-based iterative algorithms for the image quality trade-off: FBP seems to be more in favor of larger number of views while the TV-based algorithm is more robust to different data conditions (number of views and exposure levels) than the FBP algorithm. The studies can provide a general guideline for image-quality optimization for CBCT used in IGRT and other applications.

  19. Robust linear registration of CT images using random regression forests

    Science.gov (United States)

    Konukoglu, Ender; Criminisi, Antonio; Pathak, Sayan; Robertson, Duncan; White, Steve; Haynor, David; Siddiqui, Khan

    2011-03-01

    Global linear registration is a necessary first step for many different tasks in medical image analysis. Comparing longitudinal studies1, cross-modality fusion2, and many other applications depend heavily on the success of the automatic registration. The robustness and efficiency of this step is crucial as it affects all subsequent operations. Most common techniques cast the linear registration problem as the minimization of a global energy function based on the image intensities. Although these algorithms have proved useful, their robustness in fully automated scenarios is still an open question. In fact, the optimization step often gets caught in local minima yielding unsatisfactory results. Recent algorithms constrain the space of registration parameters by exploiting implicit or explicit organ segmentations, thus increasing robustness4,5. In this work we propose a novel robust algorithm for automatic global linear image registration. Our method uses random regression forests to estimate posterior probability distributions for the locations of anatomical structures - represented as axis aligned bounding boxes6. These posterior distributions are later integrated in a global linear registration algorithm. The biggest advantage of our algorithm is that it does not require pre-defined segmentations or regions. Yet it yields robust registration results. We compare the robustness of our algorithm with that of the state of the art Elastix toolbox7. Validation is performed via 1464 pair-wise registrations in a database of very diverse 3D CT images. We show that our method decreases the "failure" rate of the global linear registration from 12.5% (Elastix) to only 1.9%.

  20. Blockwise conjugate gradient methods for image reconstruction in volumetric CT.

    Science.gov (United States)

    Qiu, W; Titley-Peloquin, D; Soleimani, M

    2012-11-01

    Cone beam computed tomography (CBCT) enables volumetric image reconstruction from 2D projection data and plays an important role in image guided radiation therapy (IGRT). Filtered back projection is still the most frequently used algorithm in applications. The algorithm discretizes the scanning process (forward projection) into a system of linear equations, which must then be solved to recover images from measured projection data. The conjugate gradients (CG) algorithm and its variants can be used to solve (possibly regularized) linear systems of equations Ax=b and linear least squares problems minx∥b-Ax∥2, especially when the matrix A is very large and sparse. Their applications can be found in a general CT context, but in tomography problems (e.g. CBCT reconstruction) they have not widely been used. Hence, CBCT reconstruction using the CG-type algorithm LSQR was implemented and studied in this paper. In CBCT reconstruction, the main computational challenge is that the matrix A usually is very large, and storing it in full requires an amount of memory well beyond the reach of commodity computers. Because of these memory capacity constraints, only a small fraction of the weighting matrix A is typically used, leading to a poor reconstruction. In this paper, to overcome this difficulty, the matrix A is partitioned and stored blockwise, and blockwise matrix-vector multiplications are implemented within LSQR. This implementation allows us to use the full weighting matrix A for CBCT reconstruction without further enhancing computer standards. Tikhonov regularization can also be implemented in this fashion, and can produce significant improvement in the reconstructed images.

  1. SU-E-I-84: Accuracy Comparison of Multi-Modality Image-Based Volumes of Rodent Solid Tumors Using In-Air Micro-CT Image Volume

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y [University of Kansas Hospital, Kansas City, KS (United States); Fullerton, G; Goins, B [University of Texas Health Science Center at San Antonio, San Antonio, TX (United States)

    2015-06-15

    Purpose: Tumor volume is considered as a better predictor for therapy response monitoring and tumor staging over Response Evaluation Criteria In Solid Tumors (RECIST) or World Health Organization (WHO) criteria. In this study, the accuracy of subcutaneous rodent tumor volumes using preclinical magnetic resonance imaging (MRI), micro-computed tomography (micro-CT) and ultrasound (US) equipment and with an external caliper was compared using in-air micro-CT image volume of excised tumors determined as reference tumor volume in our prior study. Methods: MR, US and micro-CT images of subcutaneous SCC4 head and neck tumor xenografts were acquired 4, 6, 9, 11 and 13 days after tumor cell inoculation. Before MR and US scans, caliper measurements were made. After tumors were excised, in-air micro-CT imaging and ex vivo caliper measurements were performed. Tumor volumes were calculated using formula V = (π/6)*a*b*c where a, b and c are the maximum diameters in three perpendicular dimensions determined by the three image modalities and caliper, and compared with reference tumor volume by linear regression analysis as well as Bland-Altman plots. A one-way Analysis of Variance (ANOVA) test was also performed to compare volumes among caliper measurements. Results: The correlation coefficients (R2) of the regression lines for tumor volumes measured by the three imaging modalities and caliper were 0.9939, 0.9669, 0.9806, 0.9274, 0.9619 and 0.9819 for MRI, US and micro-CT, caliperbeforeMRI, caliperbeforeUS and ex vivo caliper respectively. In Bland-Altman plots, the average of tumor volume difference from reference tumor volume (bias) was significant for caliper and micro- CT, but not for MRI and US. Comparison of caliper measurements showed a significant difference (p < 0.05). Conclusion: Using the in-air micro-CT image volume, tumor volume measured by MRI was the most accurate among the three imaging modalities. In vivo caliper volume measurements showed unreliability while ex

  2. Application of time sampling in brain CT perfusion imaging for dose reduction

    Science.gov (United States)

    Lee, S. H.; Kim, J. H.; Kim, K. G.; Park, S. J.; Im, Jung Gi

    2007-03-01

    The purpose of this study is to determine a stable sampling rate not to be affected by sampling shift for reducing radiation exposure with time sampling and interpolation in cerebral perfusion CT examination. Original images were obtained every 1 second for 40 time series from 3 patients, respectively. Time sampling was performed with sampling intervals (SI) from 2 to 10 seconds. Sampling shift was applied from +1 to SI-1 for each sampling rate. For each patient, 30 tissue concentration time-course data were collected, and arterial input curves were fitted by gamma-variate function. The sinc function was introduced for interpolation. Deconvolution analysis based on SVD was performed for quantifying perfusion parameters. The perfusion values through time-varying sampling and interpolation were statistically compared with the original perfusion values. The mean CBF values with increase of sampling interval and shift magnitude from the collected data had a wider fluctuation pattern centering around the original mean CBF. The mean CBV values had a similar tendency to the mean CBF values, but a relatively narrower deviation. The mean MTT values were fluctuated reversely to the trend of the mean CBF values. The stable sampling interval for quantifying perfusion parameters with lower radiation exposure was statistically acceptable up to 4 seconds. These results indicate that sampling shift limits sampling rate for acquiring acceptable perfusion values. This study will help in selecting more reasonable sampling rate for low-radiation-dose CT examination.

  3. Computer aided segmentation of kidneys using locally shape constrained deformable models on CT images

    Science.gov (United States)

    Erdt, Marius; Sakas, Georgios

    2010-03-01

    This work presents a novel approach for model based segmentation of the kidney in images acquired by Computed Tomography (CT). The developed computer aided segmentation system is expected to support computer aided diagnosis and operation planning. We have developed a deformable model based approach based on local shape constraints that prevents the model from deforming into neighboring structures while allowing the global shape to adapt freely to the data. Those local constraints are derived from the anatomical structure of the kidney and the presence and appearance of neighboring organs. The adaptation process is guided by a rule-based deformation logic in order to improve the robustness of the segmentation in areas of diffuse organ boundaries. Our work flow consists of two steps: 1.) a user guided positioning and 2.) an automatic model adaptation using affine and free form deformation in order to robustly extract the kidney. In cases which show pronounced pathologies, the system also offers real time mesh editing tools for a quick refinement of the segmentation result. Evaluation results based on 30 clinical cases using CT data sets show an average dice correlation coefficient of 93% compared to the ground truth. The results are therefore in most cases comparable to manual delineation. Computation times of the automatic adaptation step are lower than 6 seconds which makes the proposed system suitable for an application in clinical practice.

  4. Material Science Image Analysis using Quant-CT in ImageJ

    Energy Technology Data Exchange (ETDEWEB)

    Ushizima, Daniela M.; Bianchi, Andrea G. C.; DeBianchi, Christina; Bethel, E. Wes

    2015-01-05

    We introduce a computational analysis workflow to access properties of solid objects using nondestructive imaging techniques that rely on X-ray imaging. The goal is to process and quantify structures from material science sample cross sections. The algorithms can differentiate the porous media (high density material) from the void (background, low density media) using a Boolean classifier, so that we can extract features, such as volume, surface area, granularity spectrum, porosity, among others. Our workflow, Quant-CT, leverages several algorithms from ImageJ, such as statistical region merging and 3D object counter. It also includes schemes for bilateral filtering that use a 3D kernel, for parallel processing of sub-stacks, and for handling over-segmentation using histogram similarities. The Quant-CT supports fast user interaction, providing the ability for the user to train the algorithm via subsamples to feed its core algorithms with automated parameterization. Quant-CT plugin is currently available for testing by personnel at the Advanced Light Source and Earth Sciences Divisions and Energy Frontier Research Center (EFRC), LBNL, as part of their research on porous materials. The goal is to understand the processes in fluid-rock systems for the geologic sequestration of CO2, and to develop technology for the safe storage of CO2 in deep subsurface rock formations. We describe our implementation, and demonstrate our plugin on porous material images. This paper targets end-users, with relevant information for developers to extend its current capabilities.

  5. Biomechanical deformable image registration of longitudinal lung CT images using vessel information

    Science.gov (United States)

    Cazoulat, Guillaume; Owen, Dawn; Matuszak, Martha M.; Balter, James M.; Brock, Kristy K.

    2016-07-01

    Spatial correlation of lung tissue across longitudinal images, as the patient responds to treatment, is a critical step in adaptive radiotherapy. The goal of this work is to expand a biomechanical model-based deformable registration algorithm (Morfeus) to achieve accurate registration in the presence of significant anatomical changes. Six lung cancer patients previously treated with conventionally fractionated radiotherapy were retrospectively evaluated. Exhale CT scans were obtained at treatment planning and following three weeks of treatment. For each patient, the planning CT was registered to the follow-up CT using Morfeus, a biomechanical model-based deformable registration algorithm. To model the complex response of the lung, an extension to Morfeus has been developed: an initial deformation was estimated with Morfeus consisting of boundary conditions on the chest wall and incorporating a sliding interface with the lungs. It was hypothesized that the addition of boundary conditions based on vessel tree matching would provide a robust reduction of the residual registration error. To achieve this, the vessel trees were segmented on the two images by thresholding a vesselness image based on the Hessian matrix’s eigenvalues. For each point on the reference vessel tree centerline, the displacement vector was estimated by applying a variant of the Demons registration algorithm between the planning CT and the deformed follow-up CT. An expert independently identified corresponding landmarks well distributed in the lung to compute target registration errors (TRE). The TRE was: 5.8+/- 2.9 , 3.4+/- 2.3 and 1.6+/- 1.3 mm after rigid registration, Morfeus and Morfeus with boundary conditions on the vessel tree, respectively. In conclusion, the addition of boundary conditions on the vessels significantly improved the accuracy in modeling the response of the lung and tumor over the course of radiotherapy. Minimizing and modeling these geometrical uncertainties will enable

  6. Adaptive geodesic transform for segmentation of vertebrae on CT images

    Science.gov (United States)

    Gaonkar, Bilwaj; Shu, Liao; Hermosillo, Gerardo; Zhan, Yiqiang

    2014-03-01

    Vertebral segmentation is a critical first step in any quantitative evaluation of vertebral pathology using CT images. This is especially challenging because bone marrow tissue has the same intensity profile as the muscle surrounding the bone. Thus simple methods such as thresholding or adaptive k-means fail to accurately segment vertebrae. While several other algorithms such as level sets may be used for segmentation any algorithm that is clinically deployable has to work in under a few seconds. To address these dual challenges we present here, a new algorithm based on the geodesic distance transform that is capable of segmenting the spinal vertebrae in under one second. To achieve this we extend the theory of the geodesic distance transforms proposed in1 to incorporate high level anatomical knowledge through adaptive weighting of image gradients. Such knowledge may be provided by the user directly or may be automatically generated by another algorithm. We incorporate information 'learnt' using a previously published machine learning algorithm2 to segment the L1 to L5 vertebrae. While we present a particular application here, the adaptive geodesic transform is a generic concept which can be applied to segmentation of other organs as well.

  7. Flat-Panel CT as a new perinterventional imaging modality in aortic stentgraft procedures. Work in progress; Flachdetektor-CT als ergaenzende Untersuchung bei der endoluminalen Behandlung von thorakalen und abdominellen Aortenaneurysmen. Erste klinische Erfahrungen

    Energy Technology Data Exchange (ETDEWEB)

    Rabitsch, E.; Celedin, S.; Kau, T.; Illiasch, H.; Hausegger, K. [Inst. fuer diagnostische und interventionelle Radiologie, LKH Klagenfurt (Austria)

    2008-02-15

    Purpose: to evaluate the value of flat-panel CT (FP-CT) as a new perinterventional imaging modality in aortic stentgraft procedures. Materials and methods: FP-CT was performed in 21 patients (19 males, mean age 77, range 54 to 90) from June 2005 to February 2007 immediately after endovascular treatment of thoracic and abdominal aortic aneurysms on the angiographic table. Nine thoracic aortic aneurysms were treated with Zenith trademark -endoprosthesis. Nine of twelve abdominal aortic aneurysms were treated with Zenith trademark -Endoprosthesis and three with an Excluder trademark -Endoprosthesis. Images were acquired with a rotating C-arm and the following parameters: during an acquisition time of 20 seconds and at a rotation of 217 degrees, 538 projections were acquired. Contrast agent was administered in 14 patients. Images were displayed in MIP, MPR and VRT mode. Results: in all patients the stentgraft was shown exactly and the alignment of the prosthesis along the landing zones was well displayed. The aneurismal sack was well shown in all patients. 1 x an endoleak II was detected, 1 x an angiographically verified endoleak I was not detected. In one patient distal extension was considered due to suspected short stentgraft at the distal neck. Flat-panel CT showed sufficient neck coverage and no extension was inserted. Due to artifacts of the prosthesis, the platinum markers and the guide wire as well as due to pulsation of the aorta, the resolution of detail decreased and reduced the visualization of the alignment. (orig.)

  8. Hepatic CT image retrieval based on the combination of Gabor filters and support vector machine

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Content-based image retrieval has been an active area of research for more than ten years.Gabor schemes and support vector machine (SVM) method have been proven effective in image representation and classification. In this paper,we propose a retrieval scheme based on Gabor filters and SVMs for hepatic computed tomography (CT) images query.In our experiments,a batch of hepatic CT images containing several types of CT findings are used for the retrieval test.Precision comparison between our scheme and existing methods is presented.

  9. Dual-energy CT (DECT) imaging of tophi and monosodium urate deposits in a patient with longstanding anorexia nervosa

    DEFF Research Database (Denmark)

    Weihe, Johan Petur; Birger Morillon, Melanie; Lambrechtsen, Jess

    Dual-energy CT (DECT) imaging of tophi and monosodium urate deposits in a patient with longstanding anorexia nervosa......Dual-energy CT (DECT) imaging of tophi and monosodium urate deposits in a patient with longstanding anorexia nervosa...

  10. Dual-energy CT (DECT) imaging of tophi and monosodium urate deposits in a patient with longstanding anorexia nervosa

    DEFF Research Database (Denmark)

    Weihe, Johan Petur; Birger Morillon, Melanie; Lambrechtsen, Jess

    Dual-energy CT (DECT) imaging of tophi and monosodium urate deposits in a patient with longstanding anorexia nervosa......Dual-energy CT (DECT) imaging of tophi and monosodium urate deposits in a patient with longstanding anorexia nervosa...

  11. Dual-energy CT (DECT) imaging of tophi and monosodium urate deposits in a patient with longstanding anorexia nervosa

    DEFF Research Database (Denmark)

    Weihe, Johan Petur; Birger Morillon, Melanie; Lambrechtsen, Jess;

    2014-01-01

    Dual-energy CT (DECT) imaging of tophi and monosodium urate deposits in a patient with longstanding anorexia nervosa......Dual-energy CT (DECT) imaging of tophi and monosodium urate deposits in a patient with longstanding anorexia nervosa...

  12. Towards respiration management in radiation treatment of lung tumors: transferring regions of interest from planning CT to kilovoltage X-ray images.

    Science.gov (United States)

    Ataer-Cansizoglu, Esra; Bas, Erhan; Yousuf, M; You, Sheng; D'Souza, Warren D; Erdogmus, Deniz

    2010-01-01

    Tracking of lung tumors is imperative for improved radiotherapy treatment. However, the motion of the thoracic organs makes it a complicated task. 4D CT images acquired prior to treatment provide valuable information regarding the motion of organs and tumor, since it is manually annotated. In order to track tumors using treatment-day X-ray images (kV images), we need to find the correspondence with CT images so that projection of tumor region of interest will provide a good estimate about the position of the tumor on the X-ray image. In this study, we propose a method to estimate the alignment and respiration phase corresponding to X-ray images using 4D CT data. Our approach generates Digitally Reconstructed Radiographs (DRRs) using bilateral filter smoothing and computes rigid registration with kV images since the position and orientation of patient might differ between CT and treatment-day image acquisition processes. Instead of using landmark points, our registration method makes use of Kernel Density Estimation over the edges that are not affected much by respiration. To estimate the phase of X-ray, we apply template matching techniques between the lung regions of X-ray and registered DRRs. Our approach gives accurate results for rigid registration and provides a starting point to track tumors using the X-ray images during the treatment.

  13. Assessment of image quality of 64-row Dual Source versus Single Source CT coronary angiography on heart rate: A phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Dikkers, R. [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: r.dikkers@rad.umcg.nl; Greuter, M.J.W. [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: m.j.w.greuter@rad.umcg.nl; Kristanto, W. [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: w.kristanto@rad.umcg.nl; Ooijen, P.M.A. van [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: p.m.a.van.ooyen@rad.umcg.nl; Sijens, P.E. [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: p.e.sijens@rad.umcg.nl; Willems, T.P. [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: t.p.willems@rad.umcg.nl; Oudkerk, M. [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: m.oudkerk@rad.umcg.nl

    2009-04-15

    Purpose: To assess the influence of temporal resolution on image quality of computed tomographic (CT) coronary angiography by comparing 64-row Dual Source CT (DSCT) and Single Source CT (SSCT) at different heart rates. Methods: An anthropomorphic moving heart phantom was scanned at rest, and at 50 beats per minute (bpm) up to 110 bpm, with intervals of 10 bpm. 3D volume rendered images and curved multi-planar reconstructions (MPRs) were acquired and image quality of the coronary arteries was rated on a 5-points scale (1 = poor image quality with many artefacts, 5 = excellent image quality) for each heart rate and each scanner by 3 observers. Paired sample t-test and Wilcoxon Signed Ranks test were used to assess clinically relevant differences between both modalities. Results: The mean image quality scores at 70, 100 and 110 bpm were significantly higher for DSCT compared to SSCT. The overall mean image quality scores for DSCT (4.2 {+-} 0.6) and SSCT (3.0 {+-} 1.1) also differed significantly (p < 0.001). Conclusion: These initial results show a clinically relevant overall higher image quality for DSCT compared to SSCT, especially at heart rates of 70, 100 and 110 bpm. With its comparatively high image quality and low radiation dose, DSCT appears to be the method of choice in CT coronary angiography at heart rates above 70 bpm.

  14. Pituitary Prolactinoma Imaged by 99mTc-Sestamibi SPECT/CT in a Multiple Endocrine Neoplasia Type 1 Patient.

    Science.gov (United States)

    Pan, Yu; Lv, Jing; Guo, Rui; Pan, Mengyi; Zhang, Yifan

    2016-06-01

    A 35-year-old woman who had undergone bilateral inferior parathyroidectomy for primary hyperparathyroidism was referred to our hospital to evaluate the cause of irregular menses, galactorrhea, and paroxysmal headache. Multiple endocrine neoplasia type 1 was then suspected for the high levels of plasma prolactin, parathyroid hormone, serum calcium, insulin, and related symptoms. A Tc-sestamibi SPECT/CT acquired to evaluate parathyroid glands unexpectedly revealed an increased accumulation in the pituitary gland, which was further confirmed by enhanced magnetic resonance imaging as a pituitary microadenoma. Bromocriptine treatment gradually reduced the prolactin level.

  15. Multi-detector CT imaging in the postoperative orthopedic patient with metal hardware.

    Science.gov (United States)

    Vande Berg, Bruno; Malghem, Jacques; Maldague, Baudouin; Lecouvet, Frederic

    2006-12-01

    Multi-detector CT imaging (MDCT) becomes routine imaging modality in the assessment of the postoperative orthopedic patients with metallic instrumentation that degrades image quality at MR imaging. This article reviews the physical basis and CT appearance of such metal-related artifacts. It also addresses the clinical value of MDCT in postoperative orthopedic patients with emphasis on fracture healing, spinal fusion or arthrodesis, and joint replacement. MDCT imaging shows limitations in the assessment of the bone marrow cavity and of the soft tissues for which MR imaging remains the imaging modality of choice despite metal-related anatomic distortions and signal alteration.

  16. The effect of a chest imaging lecture on emergency department doctors' ability to interpret chest CT images: a randomized study.

    Science.gov (United States)

    Keijzers, Gerben; Sithirasenan, Vasugi

    2012-02-01

    To assess the chest computed tomography (CT) imaging interpreting skills of emergency department (ED) doctors and to study the effect of a CT chest imaging interpretation lecture on these skills. Sixty doctors in two EDs were randomized, using computerized randomization, to either attend a chest CT interpretation lecture or not to attend this lecture. Within 2 weeks of the lecture, the participants completed a questionnaire on demographic variables, anatomical knowledge, and diagnostic interpretation of 10 chest CT studies. Outcome measures included anatomical knowledge score, diagnosis score, and the combined overall score, all expressed as a percentage of correctly answered questions (0-100). Data on 58 doctors were analyzed, of which 27 were randomized to attend the lecture. The CT interpretation lecture did not have an effect on anatomy knowledge scores (72.9 vs. 70.2%), diagnosis scores (71.2 vs. 69.2%), or overall scores (71.4 vs. 69.5%). Twenty-nine percent of doctors stated that they had a systematic approach to chest CT interpretation. Overall self-perceived competency for interpreting CT imaging (brain, chest, abdomen) was low (between 3.2 and 5.2 on a 10-point Visual Analogue Scale). A single chest CT interpretation lecture did not improve chest CT interpretation by ED doctors. Less than one-third of doctors had a systematic approach to chest CT interpretation. A standardized systematic approach may improve interpretation skills.

  17. Effects of radiation dose reduction in Volume Perfusion CT imaging of acute ischemic stroke

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Ahmed E. [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Radiology, Tuebingen (Germany); Brockmann, Carolin; Afat, Saif; Pjontek, Rastislav; Nikobashman, Omid; Brockmann, Marc A.; Wiesmann, Martin [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Yang, Zepa; Kim, Changwon [Seoul National University, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Suwon (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Kim, Jong Hyo [Seoul National University, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Suwon (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, Suwon (Korea, Republic of)

    2015-12-15

    To examine the influence of radiation dose reduction on image quality and sensitivity of Volume Perfusion CT (VPCT) maps regarding the detection of ischemic brain lesions. VPCT data of 20 patients with suspected ischemic stroke acquired at 80 kV and 180 mAs were included. Using realistic reduced-dose simulation, low-dose VPCT datasets with 144 mAs, 108 mAs, 72 mAs and 36 mAs (80 %, 60 %, 40 % and 20 % of the original levels) were generated, resulting in a total of 100 datasets. Perfusion maps were created and signal-to-noise-ratio (SNR) measurements were performed. Qualitative analyses were conducted by two blinded readers, who also assessed the presence/absence of ischemic lesions and scored CBV and CBF maps using a modified ASPECTS-score. SNR of all low-dose datasets were significantly lower than those of the original datasets (p <.05). All datasets down to 72 mAs (40 %) yielded sufficient image quality and high sensitivity with excellent inter-observer-agreements, whereas 36 mAs datasets (20 %) yielded poor image quality in 15 % of the cases with lower sensitivity and inter-observer-agreements. Low-dose VPCT using decreased tube currents down to 72 mAs (40 % of original radiation dose) produces sufficient perfusion maps for the detection of ischemic brain lesions. (orig.)

  18. Effect of anatomical backgrounds on detectability in volumetric cone beam CT images

    Science.gov (United States)

    Han, Minah; Park, Subok; Baek, Jongduk

    2016-03-01

    As anatomical noise is often a dominating factor affecting signal detection in medical imaging, we investigate the effects of anatomical backgrounds on signal detection in volumetric cone beam CT images. Signal detection performances are compared between transverse and longitudinal planes with either uniform or anatomical backgrounds. Sphere objects with diameters of 1mm, 5mm, 8mm, and 11mm are used as the signals. Three-dimensional (3D) anatomical backgrounds are generated using an anatomical noise power spectrum, 1/fβ, with β=3, equivalent to mammographic background [1]. The mean voxel value of the 3D anatomical backgrounds is used as an attenuation coefficient of the uniform background. Noisy projection data are acquired by the forward projection of the uniform and anatomical 3D backgrounds with/without sphere lesions and by the addition of quantum noise. Then, images are reconstructed by an FDK algorithm [2]. For each signal size, signal detection performances in transverse and longitudinal planes are measured by calculating the task SNR of a channelized Hotelling observer with Laguerre-Gauss channels. In the uniform background case, transverse planes yield higher task SNR values for all sphere diameters but 1mm. In the anatomical background case, longitudinal planes yield higher task SNR values for all signal diameters. The results indicate that it is beneficial to use longitudinal planes to detect spherical signals in anatomical backgrounds.

  19. Investigation of saddle trajectories for cardiac CT imaging in cone-beam geometry

    Energy Technology Data Exchange (ETDEWEB