Science.gov

Sample records for dynamic computed tomography

  1. Arterioportal shunts on dynamic computed tomography

    SciTech Connect

    Nakayama, T.; Hiyama, Y.; Ohnishi, K.; Tsuchiya, S.; Kohno, K.; Nakajima, Y.; Okuda, K.

    1983-05-01

    Thirty-two patients, 20 with hepatocelluar carcinoma and 12 with liver cirrhosis, were examined by dynamic computed tomography (CT) using intravenous bolus injection of contrast medium and by celiac angiography. Dynamic CT disclosed arterioportal shunting in four cases of hepatocellular carcinoma and in one of cirrhosis. In three of the former, the arterioportal shunt was adjacent to a mass lesion on CT, suggesting tumor invasion into the portal branch. In one with hepatocellular carcinoma, the shunt was remote from the mass. In the case with cirrhosis, there was no mass. In these last two cases, the shunt might have been caused by prior percutaneous needle puncture. In another case of hepatocellular carcinoma, celiac angiography but not CT demonstrated an arterioportal shunt. Thus, dynamic CT was diagnostic in five of six cases of arteriographically demonstrated arterioportal shunts.

  2. Spatiotemporal computed tomography of dynamic processes

    NASA Astrophysics Data System (ADS)

    Kaestner, Anders; Münch, Beat; Trtik, Pavel; Butler, Les

    2011-12-01

    Modern computed tomography (CT) equipment allowing fast 3-D imaging also makes it possible to monitor dynamic processes by 4-D imaging. Because the acquisition time of various 3-D-CT systems is still in the range of at least milliseconds or even hours, depending on the detector system and the source, the balance of the desired temporal and spatial resolution must be adjusted. Furthermore, motion artifacts will occur, especially at high spatial resolution and longer measuring times. We propose two approaches based on nonsequential projection angle sequences allowing a convenient postacquisition balance of temporal and spatial resolution. Both strategies are compatible with existing instruments, needing only a simple reprograming of the angle list used for projection acquisition and care with the projection order list. Both approaches will reduce the impact of artifacts due to motion. The strategies are applied and validated with cold neutron imaging of water desorption from originally saturated particles during natural air-drying experiments and with x-ray tomography of a polymer blend heated during imaging.

  3. Computed Tomography

    NASA Astrophysics Data System (ADS)

    Castellano, Isabel; Geleijns, Jacob

    After its clinical introduction in 1973, computed tomography developed from an x-ray modality for axial imaging in neuroradiology into a versatile three dimensional imaging modality for a wide range of applications in for example oncology, vascular radiology, cardiology, traumatology and even in interventional radiology. Computed tomography is applied for diagnosis, follow-up studies and screening of healthy subpopulations with specific risk factors. This chapter provides a general introduction in computed tomography, covering a short history of computed tomography, technology, image quality, dosimetry, room shielding, quality control and quality criteria.

  4. Dynamic 3D computed tomography scanner for vascular imaging

    NASA Astrophysics Data System (ADS)

    Lee, Mark K.; Holdsworth, David W.; Fenster, Aaron

    2000-04-01

    A 3D dynamic computed-tomography (CT) scanner was developed for imaging objects undergoing periodic motion. The scanner system has high spatial and sufficient temporal resolution to produce quantitative tomographic/volume images of objects such as excised arterial samples perfused under physiological pressure conditions and enables the measurements of the local dynamic elastic modulus (Edyn) of the arteries in the axial and longitudinal directions. The system was comprised of a high resolution modified x-ray image intensifier (XRII) based computed tomographic system and a computer-controlled cardiac flow simulator. A standard NTSC CCD camera with a macro lens was coupled to the electro-optically zoomed XRII to acquire dynamic volumetric images. Through prospective cardiac gating and computer synchronized control, a time-resolved sequence of 20 mm thick high resolution volume images of porcine aortic specimens during one simulated cardiac cycle were obtained. Performance evaluation of the scanners illustrated that tomographic images can be obtained with resolution as high as 3.2 mm-1 with only a 9% decrease in the resolution for objects moving at velocities of 1 cm/s in 2D mode and static spatial resolution of 3.55 mm-1 with only a 14% decrease in the resolution in 3D mode for objects moving at a velocity of 10 cm/s. Application of the system for imaging of intact excised arterial specimens under simulated physiological flow/pressure conditions enabled measurements of the Edyn of the arteries with a precision of +/- kPa for the 3D scanner. Evaluation of the Edyn in the axial and longitudinal direction produced values of 428 +/- 35 kPa and 728 +/- 71 kPa, demonstrating the isotropic and homogeneous viscoelastic nature of the vascular specimens. These values obtained from the Dynamic CT systems were not statistically different (p less than 0.05) from the values obtained by standard uniaxial tensile testing and volumetric measurements.

  5. Computed Tomography (CT) - Spine

    MedlinePlus

    ... News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Spine Computed tomography (CT) of the spine is a diagnostic imaging ... Spine? What is CT Scanning of the Spine? Computed tomography, more commonly known as a CT or CAT ...

  6. Computational fluid dynamics modelling of perfusion measurements in dynamic contrast-enhanced computed tomography: development, validation and clinical applications

    NASA Astrophysics Data System (ADS)

    Peladeau-Pigeon, M.; Coolens, C.

    2013-09-01

    Dynamic contrast-enhanced computed tomography (DCE-CT) is an imaging tool that aids in evaluating functional characteristics of tissue at different stages of disease management: diagnostic, radiation treatment planning, treatment effectiveness, and monitoring. Clinical validation of DCE-derived perfusion parameters remains an outstanding problem to address prior to perfusion imaging becoming a widespread standard as a non-invasive quantitative measurement tool. One approach to this validation process has been the development of quality assurance phantoms in order to facilitate controlled perfusion ex vivo. However, most of these systems fail to establish and accurately replicate physiologically relevant capillary permeability and exchange performance. The current work presents the first step in the development of a prospective suite of physics-based perfusion simulations based on coupled fluid flow and particle transport phenomena with the goal of enhancing the understanding of clinical contrast agent kinetics. Existing knowledge about a controllable, two-compartmental fluid exchange phantom was used to validate the computational fluid dynamics (CFD) simulation model presented herein. The sensitivity of CFD-derived contrast uptake curves to contrast injection parameters, including injection duration and flow rate, were quantified and found to be within 10% accuracy. The CFD model was employed to evaluate two commonly used clinical kinetic algorithms used to derive perfusion parameters: Fick's principle and the modified Tofts model. Neither kinetic model was able to capture the true transport phenomena it aimed to represent but if the overall contrast concentration after injection remained identical, then successive DCE-CT evaluations could be compared and could indeed reflect differences in regional tissue flow. This study sets the groundwork for future explorations in phantom development and pharmaco-kinetic modelling, as well as the development of novel contrast

  7. NOTE: Independent component analysis of dynamic contrast-enhanced computed tomography images

    NASA Astrophysics Data System (ADS)

    Koh, T. S.; Yang, X.; Bisdas, S.; Lim, C. C. T.

    2006-10-01

    Independent component analysis (ICA) was applied on dynamic contrast-enhanced computed tomography images of cerebral tumours to extract spatial component maps of the underlying vascular structures, which correspond to different haemodynamic phases as depicted by the passage of the contrast medium. The locations of arteries, veins and tumours can be separately identified on these spatial component maps. As the contrast enhancement behaviour of the cerebral tumour differs from the normal tissues, ICA yields a tumour component map that reveals the location and extent of the tumour. Tumour outlines can be generated using the tumour component maps, with relatively simple segmentation methods.

  8. Computed body tomography.

    PubMed

    Alfidi, R J; Haaga, J R

    1976-12-01

    Only the surface of the diagnostic possibilities inherent in CT imaging has been scratched. Solic organ pathology is readily visible in most instances by computed tomography. With further extension of present knowledge and development of newer contrast agents, the ability of computed body tomography to image a wide range of diseases appears almost limitless.

  9. Comparison Between Perfusion Computed Tomography and Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Rectal Cancer

    SciTech Connect

    Kierkels, Roel G.J.; Backes, Walter H.; Janssen, Marco H.M.; Buijsen, Jeroen; Beets-Tan, Regina G.H.; Lambin, Philippe; Lammering, Guido; Oellers, Michel C.; Aerts, Hugo J.W.L.

    2010-06-01

    Purpose: To compare pretreatment scans with perfusion computed tomography (pCT) vs. dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in rectal tumors. Methods and Materials: Nineteen patients diagnosed with rectal cancer were included in this prospective study. All patients underwent both pCT and DCE-MRI. Imaging was performed on a dedicated 40-slice CT-positron emission tomography system and a 3-T MRI system. Dynamic contrast enhancement was measured in tumor tissue and the external iliac artery. Tumor perfusion was quantified in terms of pharmacokinetic parameters: transfer constant K{sup trans}, fractional extravascular-extracellular space v{sub e}, and fractional plasma volume v{sub p}. Pharmacokinetic parameter values and their heterogeneity (by 80% quantile value) were compared between pCT and DCE-MRI. Results: Tumor K{sup trans} values correlated significantly for the voxel-by-voxel-derived median (Kendall's tau correlation, tau = 0.81, p < 0.001) and 80% quantile (tau = 0.54, p = 0.04), as well as for the averaged uptake (tau = 0.58, p = 0.03). However, no significant correlations were found for v{sub e} and v{sub p} derived from the voxel-by-voxel-derived median and 80% quantile and derived from the averaged uptake curves. Conclusions: This study demonstrated for the first time that pCT provides K{sup trans} values comparable to those of DCE-MRI. However, no correlation was found for the v{sub e} and v{sub p} parameters between CT and MRI. Computed tomography can serve as an alternative modality to MRI for the in vivo evaluation of tumor angiogenesis in terms of the transfer constant K{sup trans}.

  10. Sinogram smoothing techniques for myocardial blood flow estimation from dose-reduced dynamic computed tomography

    PubMed Central

    Modgil, Dimple; Alessio, Adam M.; Bindschadler, Michael D.; La Rivière, Patrick J.

    2014-01-01

    Abstract. Dynamic contrast-enhanced computed tomography (CT) could provide an accurate and widely available technique for myocardial blood flow (MBF) estimation to aid in the diagnosis and treatment of coronary artery disease. However, one of its primary limitations is the radiation dose imparted to the patient. We are exploring techniques to reduce the patient dose by either reducing the tube current or by reducing the number of temporal frames in the dynamic CT sequence. Both of these dose reduction techniques result in noisy data. In order to extract the MBF information from the noisy acquisitions, we have explored several data-domain smoothing techniques. In this work, we investigate two specific smoothing techniques: the sinogram restoration technique in both the spatial and temporal domains and the use of the Karhunen–Loeve (KL) transform to provide temporal smoothing in the sinogram domain. The KL transform smoothing technique has been previously applied to dynamic image sequences in positron emission tomography. We apply a quantitative two-compartment blood flow model to estimate MBF from the time-attenuation curves and determine which smoothing method provides the most accurate MBF estimates in a series of simulations of different dose levels, dynamic contrast-enhanced cardiac CT acquisitions. As measured by root mean square percentage error (% RMSE) in MBF estimates, sinogram smoothing generally provides the best MBF estimates except for the cases of the lowest simulated dose levels (tube current=25  mAs, 2 or 3 s temporal spacing), where the KL transform method provides the best MBF estimates. The KL transform technique provides improved MBF estimates compared to conventional processing only at very low doses (<7  mSv). Results suggest that the proposed smoothing techniques could provide high fidelity MBF information and allow for substantial radiation dose savings. PMID:25642441

  11. Liver metastasis from hepatoid adenocarcinoma of the stomach mimicking hepatocellular carcinoma: Dynamic computed tomography findings

    PubMed Central

    Lin, Yang-Yu; Chen, Chien-Ming; Huang, Yu-Hsiu; Lin, Cheng-Yu; Chu, Sung-Yu; Hsu, Ming-Yi; Pan, Kuang-Tse; Tseng, Jeng-Hwei

    2015-01-01

    AIM: To evaluate the dynamic computed tomography (CT) findings of liver metastasis from hepatoid adenocarcinoma of the stomach (HAS) and compared them with hepatocellular carcinoma (HCC). METHODS: Between January 2000 and January 2015, 8 patients with pathologically proven HAS and liver metastases were enrolled. Basic tumor status was evaluated for the primary tumor location and metastatic sites. The CT findings of the liver metastases were analyzed for tumor number and size, presence of tumor necrosis, hemorrhage, venous tumor thrombosis, and dynamic enhancing pattern. RESULTS: The body and antrum were the most common site for primary HAS (n = 7), and observed metastatic sites included the liver (n = 8), lymph nodes (n = 7), peritoneum (n = 4), and lung (n = 2). Most of the liver metastases exhibited tumor necrosis regardless of tumor size. By contrast, tumor hemorrhage was observed only in liver lesions larger than 5 cm (n = 4). Three patterns of venous tumor thrombosis were identified: direct venous invasion by the primary HAS (n = 1), direct venous invasion by the liver metastases (n = 7), and isolated portal vein tumor thrombosis (n = 2). Dynamic CT revealed arterial hyperattenuation and late phase washout in all the liver metastases. CONCLUSION: On dynamic CT, liver metastasis from HAS shared many imaging similarities with HCC. For liver nodules, the presence of isolated portal vein tumor thrombosis and a tendency for tumor necrosis are imaging clues that suggest the diagnosis of HAS. PMID:26730164

  12. Evaluation of static and dynamic perfusion cardiac computed tomography for quantitation and classification tasks.

    PubMed

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R; La Riviere, Patrick J; Alessio, Adam M

    2016-04-01

    Cardiac computed tomography (CT) acquisitions for perfusion assessment can be performed in a dynamic or static mode. Either method may be used for a variety of clinical tasks, including (1) stratifying patients into categories of ischemia and (2) using a quantitative myocardial blood flow (MBF) estimate to evaluate disease severity. In this simulation study, we compare method performance on these classification and quantification tasks for matched radiation dose levels and for different flow states, patient sizes, and injected contrast levels. Under conditions simulated, the dynamic method has low bias in MBF estimates (0 to [Formula: see text]) compared to linearly interpreted static assessment (0.45 to [Formula: see text]), making it more suitable for quantitative estimation. At matched radiation dose levels, receiver operating characteristic analysis demonstrated that the static method, with its high bias but generally lower variance, had superior performance ([Formula: see text]) in stratifying patients, especially for larger patients and lower contrast doses [area under the curve [Formula: see text] to 96 versus 0.86]. We also demonstrate that static assessment with a correctly tuned exponential relationship between the apparent CT number and MBF has superior quantification performance to static assessment with a linear relationship and to dynamic assessment. However, tuning the exponential relationship to the patient and scan characteristics will likely prove challenging. This study demonstrates that the selection and optimization of static or dynamic acquisition modes should depend on the specific clinical task.

  13. Computed Tomography (CT) -- Head

    MedlinePlus

    ... further information please consult the ACR Manual on Contrast Media and its references. The risk of serious allergic ... Angiography (CTA) Stroke Brain Tumors Computer Tomography (CT) Safety During Pregnancy Head and Neck Cancer X-ray, ...

  14. Computed Tomography (CT) -- Sinuses

    MedlinePlus

    ... further information please consult the ACR Manual on Contrast Media and its references. The risk of serious allergic ... X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Computed Tomography (CT) - Sinuses About ...

  15. Dynamic Drug-Induced Sleep Computed Tomography in Adults With Obstructive Sleep Apnea

    PubMed Central

    Li, Hsueh-Yu; Lo, Yu-Lun; Wang, Chao-Jan; Hsin, Li-Jen; Lin, Wan-Ni; Fang, Tuan-Jen; Lee, Li-Ang

    2016-01-01

    Surgical success for obstructive sleep apnea (OSA) depends on identifying sites of obstruction in the upper airway. In this study, we investigated sites of obstruction by evaluating dynamic changes in the upper airway using drug-induced sleep computed tomography (DI-SCT) in patients with OSA. Thirty-five adult patients with OSA were prospectively enrolled. Sleep was induced with propofol under light sedation (bispectral index 70–75), and low-dose 320-detector row CT was performed for 10 seconds over a span of 2–3 respiratory cycles with supporting a continuous positive airway pressure model. Most (89%) of the patients had multi-level obstructions. Total obstruction most commonly occurred in the velum (86%), followed by the tongue (57%), oropharyngeal lateral wall (49%), and epiglottis (26%). There were two types of anterior-posterior obstruction of the soft palate, uvular (94%) and velar (6%), and three types of tongue obstruction, upper (30%), lower (37%), and upper plus lower obstruction (33%). DI-SCT is a fast and safe tool to identify simulated sleep airway obstruction in patients with OSA. It provides data on dynamic airway movement in the sagittal view which can be used to differentiate palate and tongue obstructions, and this can be helpful when planning surgery for patients with OSA. PMID:27762308

  16. Dynamic computed tomography of the normal feline hypophysis cerebri (Glandula pituitaria).

    PubMed

    Tyson, Reid; Graham, John P; Bermingham, Eden; Randall, Stacy; Berry, Clifford R

    2005-01-01

    The purpose of this study was to describe normal feline hypophyseal mensuration and contrast enhancement characteristics using dynamic computed tomography (CT) imaging. An intravenous bolus of an ionic iodinated contrast medium was administered to eight cats using a pressure injector while dynamic CT images were obtained every 5 s for five cats and every 7 s for three cats for a total imaging time of 5 min. Each pituitary was measured at its maximum height and width on the peak contrast medium enhancement image. A hand-drawn region of interest was placed around each hypophysis cerebri and time attenuation curves were generated. The specific enhancement pattern of the hypophysis cerebri for each cat was recorded. The mean width and height of the hypophysis cerebri was 5.2 +/- 0.4 (average +/- SD) mm and 3.1 +/- 0.3 mm, respectively. The mean time to maximum contrast enhancement was 28.6 +/- 14.8 s (range 14-50 s) from the onset of contrast medium injection. Four cats had initial dorsal and peripheral contrast enhancement patterns of the hypophysis cerebri, while four cats had an initial central contrast medium enhancement pattern. The hypophysis cerebri had a homogenous appearance in all cats, 28-50 s after contrast medium injection. The average (+/- SD) clearance half-time was 292 (+/- 87) s. Normal hypophysis cerebri mensuration and contrast medium enhancement characteristics will help in clinical evaluation of the feline hypophysis cerebri.

  17. Hemodynamic assessment of partial mechanical circulatory support: data derived from computed tomography angiographic images and computational fluid dynamics

    PubMed Central

    Karmonik, Christof; Rengier, Fabian; Meredig, Hagen; Farag, Mina Berty; Müller-Eschner, Matthias; Arif, Rawa; Popov, Aron-Frederik; Kauczor, Hans-Ulrich; Karck, Matthias; Ruhparwar, Arjang

    2015-01-01

    Partial mechanical circulatory support represents a new concept for the treatment of advanced heart failure. The Circulite Synergy Micro Pump®, where the inflow cannula is connected to the left atrium and the outflow cannula to the right subclavian artery, was one of the first devices to introduce this concept to the clinic. Using computational fluid dynamics (CFD) simulations, hemodynamics in the aortic tree was visualized and quantified from computed tomography angiographic (CTA) images in two patients. A realistic computational model was created by integrating flow information from the native heart and from the Circulite device. Diastolic flow augmentation in the descending aorta but competing/antagonizing flow patterns in the proximal innominate artery was observed. Velocity time curves in the ascending aorta correlated well with those in the left common carotid, the left subclavian and the descending aorta but poorly with the one in the innominate. Our results demonstrate that CFD may be useful in providing a better understanding of the main flow patterns in mechanical circulatory support devices. PMID:25984458

  18. Analysis and Correction of Dynamic Geometric Misalignment for Nano-Scale Computed Tomography at BSRF

    PubMed Central

    Fu, Jian; Li, Chen; Liu, Zhenzhong

    2015-01-01

    Due to its high spatial resolution, synchrotron radiation x-ray nano-scale computed tomography (nano-CT) is sensitive to misalignments in scanning geometry, which occurs quite frequently because of mechanical errors in manufacturing and assembly or from thermal expansion during the time-consuming scanning. Misalignments degrade the imaging results by imposing artifacts on the nano-CT slices. In this paper, the geometric misalignment of the synchrotron radiation nano-CT has been analyzed by partial derivatives on the CT reconstruction algorithm and a correction method, based on cross correlation and least-square sinusoidal fitting, has been reported. This work comprises a numerical study of the method and its experimental verification using a dataset measured with the full-field transmission x-ray microscope nano-CT at the beamline 4W1A of the Beijing Synchrotron Radiation Facility. The numerical and experimental results have demonstrated the validity of the proposed approach. It can be applied for dynamic geometric misalignment and needs neither phantom nor additional correction scanning. We expect that this method will simplify the experimental operation of synchrotron radiation nano-CT. PMID:26509552

  19. Micro/Nano-Computed Tomography Technology for Quantitative Dynamic, Multi-scale Imaging of Morphogenesis

    PubMed Central

    Gregg, Chelsea L.; Recknagel, Andrew K.; Butcher, Jonathan T.

    2015-01-01

    Tissue morphogenesis and embryonic development are dynamic events challenging to quantify, especially considering the intricate events that happen simultaneously in different locations and time. Micro-, and more recently nano-computed tomography (micro/nanoCT), has been used for the past 15 years to characterize large 3D fields of tortuous geometries at high spatial resolution. We and others have advanced micro/nanoCT imaging strategies for quantifying tissue and organ level fate changes throughout morphogenesis. Exogenous soft tissue contrast media enables visualization of vascular lumens and tissues via extravasation. Furthermore, the emergence of antigen specific tissue contrast enables direct quantitative visualization of protein and mRNA expression. Micro-CT X-ray doses appear to be non-embryotoxic, enabling longitudinal imaging studies in live embryos. In this paper we present established soft tissue contrast protocols for obtaining high quality micro/nanoCT images and the image processing techniques useful for quantifying anatomical and physiological information from the datasets. PMID:25245686

  20. Micro/nano-computed tomography technology for quantitative dynamic, multi-scale imaging of morphogenesis.

    PubMed

    Gregg, Chelsea L; Recknagel, Andrew K; Butcher, Jonathan T

    2015-01-01

    Tissue morphogenesis and embryonic development are dynamic events challenging to quantify, especially considering the intricate events that happen simultaneously in different locations and time. Micro- and more recently nano-computed tomography (micro/nanoCT) has been used for the past 15 years to characterize large 3D fields of tortuous geometries at high spatial resolution. We and others have advanced micro/nanoCT imaging strategies for quantifying tissue- and organ-level fate changes throughout morphogenesis. Exogenous soft tissue contrast media enables visualization of vascular lumens and tissues via extravasation. Furthermore, the emergence of antigen-specific tissue contrast enables direct quantitative visualization of protein and mRNA expression. Micro-CT X-ray doses appear to be non-embryotoxic, enabling longitudinal imaging studies in live embryos. In this chapter we present established soft tissue contrast protocols for obtaining high-quality micro/nanoCT images and the image processing techniques useful for quantifying anatomical and physiological information from the data sets.

  1. Doses to skin during dynamic perfusion computed tomography of the liver.

    PubMed

    Beganovic, Adnan; Sefic-Pasic, Irmina; Skopljak-Beganovic, Amra; Kristic, Spomenka; Sunjic, Svjetlana; Mekic, Amra; Gazdic-Santic, Maja; Drljevic, Advan; Samek, Davorin

    2013-01-01

    Many new computed tomography (CT) techniques have been introduced during the recent years, one of them being CT-assisted dynamic perfusion imaging (perfusion CT, PCT). Many concerns were raised when first cases of deterministic radiation effects were reported. This paper shows how radiochromic films can be utilised as passive dosemeters for use in PCT. Radiochromic dosemeters undergo a colour change directly and do not require chemical processing. Prior to their use, they need to be calibrated. Films are placed on top and on the right side of the patient and exposed during the procedure. Readout is performed using a densitometer. Results show that average local skin doses are 0.51±0.07 and 0.42±0.04 Gy on top and on the lateral side of the patient, respectively. Results of the patient dosimetry (local skin doses) are consistent. This is due to the fact that each patient had the same CT protocol used for imaging (120 kV, 60 mA and C(vol) of 247.75 mGy). Radiochromic films designed for interventional radiology can be effectively used for local skin dose measurements in perfusion CT. Dose values obtained are below the threshold needed for deterministic effects (erythema, hair loss, etc.). These effects might happen if inappropriate CT protocol is used; one that is usually used for routine imaging.

  2. Framework for cognitive analysis of dynamic perfusion computed tomography with visualization of large volumetric data

    NASA Astrophysics Data System (ADS)

    Hachaj, Tomasz; Ogiela, Marek R.

    2012-10-01

    The proposed framework for cognitive analysis of perfusion computed tomography images is a fusion of image processing, pattern recognition, and image analysis procedures. The output data of the algorithm consists of: regions of perfusion abnormalities, anatomy atlas description of brain tissues, measures of perfusion parameters, and prognosis for infracted tissues. That information is superimposed onto volumetric computed tomography data and displayed to radiologists. Our rendering algorithm enables rendering large volumes on off-the-shelf hardware. This portability of rendering solution is very important because our framework can be run without using expensive dedicated hardware. The other important factors are theoretically unlimited size of rendered volume and possibility of trading of image quality for rendering speed. Such rendered, high quality visualizations may be further used for intelligent brain perfusion abnormality identification, and computer aided-diagnosis of selected types of pathologies.

  3. Four-dimensional computed tomography and detection of dynamic capitate subluxation.

    PubMed

    Repse, Stephen E; Amis, Benjamin; Troupis, John M

    2015-06-01

    Midcarpal instability syndrome is often misdiagnosed, leading to delayed recognition, treatment and possibly poor clinical outcome. Four-dimensional computed tomography (4D CT) has previously proved useful in assessment of the acromioclavicular joint and wrist motion, allowing clinicians and radiologists to gain an understanding of abnormalities in function as well as morphology, which often contribute to patient symptoms. We present the case of a 25-year-old male with no history of trauma who presents with several months of a right wrist clunk on both passive and active (load bearing) motion. Plain film and 1.5 Tesla MRI with intra-articular contrast demonstrates a normal appearance, without joint space, tendon or ligament disturbance. We further investigated this condition using a wide volume detector CT scanning technique (4D CT). Data from the patient's asymptomatic wrist was utilized as a comparison for this study. Assessment of cine movie files from the symptomatic wrist revealed abnormal subluxation of the capitate from the lunate when compared with the normal wrist, in which the capitate did not deviate from the concavity of the lunate and did not cross the perpendicular line from the superior pole of the lunate in any phase of motion, which we defined as capitate subluxation. 4D CT allows for detection of capitate subluxation in an earlier stage of disease progression, constituting earlier recognition and providing the opportunity for earlier treatment of the disease, potentially mitigating significant patient morbidity. We have been able to confidently identify capitate subluxation both visually (assessment of the sagittal RLC axis) and objectively (documentation of percent subluxation of the capitate beyond the superior pole of the lunate). We propose that 4D CT investigation of all functional carpal instability syndromes may be beneficial as this technique has the potential to significantly increase our knowledge of dynamic carpal bone abnormalities

  4. Computed tomography in neurocysticercosis.

    PubMed Central

    Minguetti, G; Ferreira, M V

    1983-01-01

    Neurocysticercosis is a major public health problem in developing countries. Before computed tomography became available its diagnosis was very restricted and the conventional diagnostic methods were unreliable. It also was frequently necessary to submit patients to costly and dangerous surgical procedures to confirm the precise nature of the disease. One hundred and seventy-one patients with neurocysticercosis were evaluated by computed tomography. The diagnostic findings of the different types of lesions produced by the larva of the parasite (Taenia solium) in the central nervous system, and the advantages of CT in the diagnosis of this clinical entity are described, as well as the main signs and symptoms of the patients referred for examination. The effect of corticosteroids in the acute stages of the disease and the changes they provoke in the CT images are described. Images PMID:6644318

  5. Computed tomography status

    SciTech Connect

    Hansche, B.D.

    1983-01-01

    Computed tomography (CT) is a relatively new radiographic technique which has become widely used in the medical field, where it is better known as computerized axial tomographic (CAT) scanning. This technique is also being adopted by the industrial radiographic community, although the greater range of densities, variation in samples sizes, plus possible requirement for finer resolution make it difficult to duplicate the excellent results that the medical scanners have achieved.

  6. Computed Tomography Status

    DOE R&D Accomplishments Database

    Hansche, B. D.

    1983-01-01

    Computed tomography (CT) is a relatively new radiographic technique which has become widely used in the medical field, where it is better known as computerized axial tomographic (CAT) scanning. This technique is also being adopted by the industrial radiographic community, although the greater range of densities, variation in samples sizes, plus possible requirement for finer resolution make it difficult to duplicate the excellent results that the medical scanners have achieved.

  7. Imaging and modeling of flow in porous media using clinical nuclear emission tomography systems and computational fluid dynamics

    PubMed Central

    Boutchko, Rostyslav; Rayz, Vitaliy L.; Vandehey, Nicholas T.; O’Neil, James P.; Budinger, Thomas F.; Nico, Peter S.; Druhan, Jennifer L.; Saloner, David A.; Gullberg, Grant T.; Moses, William W.

    2014-01-01

    This paper presents experimental and modeling aspects of applying nuclear emission tomography to study fluid flow in laboratory packed porous media columns of the type frequently used in geophysics, geochemistry and hydrology research. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are used as non-invasive tools to obtain dynamic 3D images of radioactive tracer concentrations. Dynamic sequences obtained using 18F-FDG PET are used to trace flow through a 5 cm diameter × 20 cm tall sand packed column with and without an impermeable obstacle. In addition, a custom-made rotating column setup placed in a clinical two-headed SPECT camera is used to image 99mTc-DTPA tracer propagation in a through-flowing column (10 cm diameter × 30 cm tall) packed with recovered aquifer sediments. A computational fluid dynamics software package FLUENT is used to model the observed flow dynamics. Tracer distributions obtained in the simulations in the smaller column uniformly packed with sand and in the column with an obstacle are remarkably similar to the reconstructed images in the PET experiments. SPECT results demonstrate strongly non-uniform flow patterns for the larger column slurry-packed with sub-surface sediment and slow upward flow. In the numerical simulation of the SPECT study, two symmetric channels with increased permeability are prescribed along the column walls, which result in the emergence of two well-defined preferential flow paths. Methods and results of this work provide new opportunities in hydrologic and biogeochemical research. The primary target application for developed technologies is non-destructive, non-perturbing, quantitative imaging of flow dynamics within laboratory scale porous media systems. PMID:24917693

  8. Dynamic computed tomography of the pituitary gland using a single slice scanner in dogs with pituitary-dependent hypercortisolism.

    PubMed

    Del Magno, Sara; Grinwis, Guy C M; Voorhout, George; Meij, Björn P

    2016-08-01

    Selective removal of the pituitary adenoma has not been advocated in dogs with pituitary-dependent hypercortisolism because the pituitary adenoma is usually not visualized on routine computed tomography (CT). Dynamic pituitary CT scanning is aimed at the detection of the pituitary flush and, indirectly, at the presence and position of the adenoma. The first aim of this retrospective study was to compare findings of a multiple slice dynamic scanning protocol with those of a single slice dynamic protocol using a single slice CT scanner. The second aim was to compare the CT findings with surgical findings, and surgical findings with histopathological findings. Computed tomography with single and multiple slice dynamic scanning protocols was performed in 86 dogs with pituitary-dependent hypercortisolism. Thirty dogs underwent transsphenoidal hypophysectomy and pituitary specimens were collected as tumor, normal, mixed and neurohypophyseal samples and processed for histology. The pituitary flush was not detected more frequent in multiple slice dynamic scanning series than in single slice dynamic scanning series. However, in non-enlarged pituitaries, the flush was seen significantly more frequently than in enlarged pituitaries. Prediction of the nature of the tissue during hypophysectomy by the surgeon was inconclusive. In conclusion, when using a single slice CT scanner, both single or multiple slice dynamic scanning protocols can be used for localization of the neurohypophyseal flush, and, indirectly, the adenoma. However, based on this study, the aim of surgery in dogs with pituitary-dependent hypercortisolism remains total adenohypophysectomy, and when the neurophypophysis is recognized, it may be left in situ. PMID:27473973

  9. Tumor Delineation Based on Time-Activity Curve Differences Assessed With Dynamic Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography in Rectal Cancer Patients

    SciTech Connect

    Janssen, Marco Aerts, Hugo; Ollers, Michel C.; Bosmans, Geert; Lee, John A.; Buijsen, Jeroen; Ruysscher, Dirk de; Lambin, Philippe; Lammering, Guido; Dekker, Andre L.A.J.

    2009-02-01

    Purpose: To develop an unsupervised tumor delineation method based on time-activity curve (TAC) shape differences between tumor tissue and healthy tissue and to compare the resulting contour with the two tumor contouring methods mostly used nowadays. Methods and Materials: Dynamic positron emission tomography-computed tomography (PET-CT) acquisition was performed for 60 min starting directly after fluorodeoxyglucose (FDG) injection. After acquisition and reconstruction, the data were filtered to attenuate noise. Correction for tissue motion during acquisition was applied. For tumor delineation, the TAC slope values were k-means clustered into two clusters. The resulting tumor contour (Contour I) was compared with a contour manually drawn by the radiation oncologist (Contour II) and a contour generated using a threshold of the maximum standardized uptake value (SUV; Contour III). Results: The tumor volumes of Contours II and III were significantly larger than the tumor volumes of Contour I, with both Contours II and III containing many voxels showing flat TACs at low activities. However, in some cases, Contour II did not cover all voxels showing upward TACs. Conclusion: Both automated SUV contouring and manual tumor delineation possibly incorrectly assign healthy tissue, showing flat TACs, as being malignant. On the other hand, in some cases the manually drawn tumor contours do not cover all voxels showing steep upward TACs, suspected to be malignant. Further research should be conducted to validate the possible superiority of tumor delineation based on dynamic PET analysis.

  10. Computed Tomography Measuring Inside Machines

    NASA Technical Reports Server (NTRS)

    Wozniak, James F.; Scudder, Henry J.; Anders, Jeffrey E.

    1995-01-01

    Computed tomography applied to obtain approximate measurements of radial distances from centerline of turbopump to leading edges of diffuser vanes in turbopump. Use of computed tomography has significance beyond turbopump application: example of general concept of measuring internal dimensions of assembly of parts without having to perform time-consuming task of taking assembly apart and measuring internal parts on coordinate-measuring machine.

  11. The dynamics of embolism repair in xylem: in vivo visualizations using high-resolution computed tomography.

    PubMed

    Brodersen, Craig R; McElrone, Andrew J; Choat, Brendan; Matthews, Mark A; Shackel, Kenneth A

    2010-11-01

    Water moves through plants under tension and in a thermodynamically metastable state, leaving the nonliving vessels that transport this water vulnerable to blockage by gas embolisms. Failure to reestablish flow in embolized vessels can lead to systemic loss of hydraulic conductivity and ultimately death. Most plants have developed a mechanism to restore vessel functionality by refilling embolized vessels, but the details of this process in vessel networks under tension have remained unclear for decades. Here we present, to our knowledge, the first in vivo visualization and quantification of the refilling process for any species using high-resolution x-ray computed tomography. Successful vessel refilling in grapevine (Vitis vinifera) was dependent on water influx from surrounding living tissue at a rate of 6 × 10(-4) μm s(-1), with individual droplets expanding over time, filling vessels, and forcing the dissolution of entrapped gas. Both filling and draining processes could be observed in the same vessel, indicating that successful refilling requires hydraulic isolation from tensions that would otherwise prevent embolism repair. Our study demonstrates that despite the presence of tensions in the bulk xylem, plants are able to restore hydraulic conductivity in the xylem. PMID:20841451

  12. Computed tomography of the body

    SciTech Connect

    Lee, J.K.T.; Stanley, R.J.

    1982-01-01

    By the end of the fourth year of clinical use, the number of articles dealing with computed body tomography (CT) had increased exponentially. Over 100 articles were published during this review period. This chapter examines new application of CT in the neck, musculoskeletal system and the breast. The chapter begins with an examination of the technical aspects of the operation and performance of CT scanners during this review period. The anatomy of various regions of the body, such as neck, chest, liver and biliary system, genitourinary tract, and pelvis are examined. Brief discussions of pediatric computed tomography, computed tomography-guided biopsy, and radiation therapy are presented. (KRM)

  13. Puffed-cheek computed tomography: a dynamic maneuver for imaging oral cavity tumors.

    PubMed

    Erdogan, Nezahat; Bulbul, Erdogan; Songu, Murat; Uluc, Engin; Onal, Kazim; Apaydin, Melda; Katilmis, Huseyin

    2012-09-01

    We conducted a prospective study to compare the effectiveness of conventional computed tomography (CT) and puffed-cheek CT in detecting the presence and extension of oral cavity malignant tumors. We enrolled 11 patients--5 men and 6 women, aged 32 to 85 years--who had a primary squamous cell carcinoma of the oral cavity. These tumors were located in the floor of the mouth in 4 patients, in the buccal mucosa in 4, in both the buccal mucosa and retromolar trigone in 2, and in the retromolar trigone only in 1. First, conventional contrast-enhanced axial CT was obtained through the oral cavity and neck in each patient. Next, axial imaging was obtained through the oral cavity while patients inflated their cheeks, pursed their lips, and held their breath. We found that the puffed-cheek CTs provided more information regarding the size and extent of the squamous cell carcinomas than did the conventional CTs. For example, in 8 patients, conventional CT could not differentiate the tumor from the normal mucosal surface, but puffed-cheek images clearly showed the surface of the tumor as distinct from the normal mucosa. More disconcerting was the fact that in the other 3 patients, conventional CTs were evaluated as normal, even though puffed-cheek imaging clearly showed the mass in each case. We conclude that puffed-cheek CT is superior to conventional CT for evaluating the mucosal surfaces of the oral cavity. It provides a clearer and more detailed picture with no downside. PMID:22996710

  14. Dynamic Computed Tomography Angiography: Role in the Evaluation of Popliteal Artery Entrapment Syndrome

    SciTech Connect

    Anil, Gopinathan Tay, Kiang-Hiong; Howe, Tse-Chiang; Tan, Bien-Soo

    2011-04-15

    This study reviews our experience with dynamic computed tomographic angiography (CTA) as an imaging modality in the evaluation of popliteal artery entrapment syndrome (PAES). Eight patients with surgically proven PAES were included in this study. Dynamic CTA studies performed with the feet in neutral and plantar flexed positions were reviewed for the detailed anatomy of the region and to define the location and extent of the stenosis, occlusions and collateral circulation. These findings were compared with intraoperative observations. CTA provided adequate angiographic and anatomic information required to arrive at the diagnosis and make a surgical decision. Thirteen limbs were affected in eight patients. There was popliteal artery occlusion in four limbs, stenosis at rest that was accentuated on stress imaging in two limbs, and patent popliteal artery with marked stenosis on stress imaging in seven limbs. Long-segment stenosis was seen in functional entrapment compared to short-segment stenosis in anatomic PAES. Anteroposterior compression of the popliteal artery in anatomic PAES unlike the side-to-side compression in functional PAES was a unique observation in this study. The CTA and surgical characterisation and classification of PAES matched in all the patients, except for misinterpretation of compressing fibrous bands as accessory slips of muscles in three limbs. In conclusion, dynamic CTA is a robust diagnostic tool that provides clinically relevant information and serves as a rapidly performed and easily available 'one-stop-shop' imaging modality in the management of PAES.

  15. Computed tomography of the prostate.

    PubMed

    Van Engelshoven, J M; Kreel, L

    1979-02-01

    The conventional anatomy of the prostate is reviewed and the computed tomography (CT) anatomy described and illustrated. The results of 55 "normal" cases were analyzed for size and relationship to the symphysis pubis, retropubic space, and bladder, as shown on CT sections correlating the features with age and possible urinary symptoms. Attention is also drawn to the differences between phleboliths and prostatic calcification. Computed tomography is an effective method of demonstrating the prostate and surrounding structures and of assessing prostatic enlargement.

  16. Qualitative and Quantitative Assessment of Adenosine Triphosphate Stress Whole-Heart Dynamic Myocardial Perfusion Imaging Using 256-Slice Computed Tomography

    PubMed Central

    Kurata, Akira; Kawaguchi, Naoto; Kido, Teruhito; Inoue, Katsuji; Suzuki, Jun; Ogimoto, Akiyoshi; Funada, Jun-ichi; Higaki, Jitsuo; Miyagawa, Masao; Vembar, Mani; Mochizuki, Teruhito

    2013-01-01

    Background The aim of this study was to investigate the correlation of the qualitative transmural extent of hypoperfusion areas (HPA) using stress dynamic whole-heart computed tomography perfusion (CTP) imaging by 256-slice CT with CTP-derived myocardial blood flow (MBF) for the estimation of the severity of coronary artery stenosis. Methods and Results Eleven patients underwent adenosine triphosphate (0.16 mg/kg/min, 5 min) stress dynamic CTP by 256-slice CT (coverage: 8 cm, 0.27 s/rotation), and 9 of the 11 patients underwent coronary angiography (CAG). Stress dynamic CTP (whole–heart datasets over 30 consecutive heart beats in systole without spatial and temporal gaps) was acquired with prospective ECG gating (effective radiation dose: 10.4 mSv). The extent of HPAs was visually graded using a 3-point score (normal, subendocardial, transmural). MBF (ml/100g/min) was measured by deconvolution. Differences in MBF (mean ± standard error) according to HPA and CAG results were evaluated. In 27 regions (3 major coronary territories in 9 patients), 11 coronary stenoses (> 50% reduction in diameter) were observed. In 353 myocardial segments, HPA was significantly related to MBF (P < 0.05; normal 295 ± 94; subendocardial 186 ± 67; and transmural 80 ± 53). Coronary territory analysis revealed a significant relationship between coronary stenosis severity and MBF (P < 0.05; non-significant stenosis [< 50%], 284 ± 97; moderate stenosis [50–70%], 184 ± 74; and severe stenosis [> 70%], 119 ± 69). Conclusion The qualitative transmural extent of HPA using stress whole-heart dynamic CTP imaging by 256-slice CT exhibits a good correlation with quantitative CTP-derived MBF and may aid in assessing the hemodynamic significance of coronary artery disease. PMID:24376774

  17. Probing the Dynamics of Biomineralization at the Pore Scale Using X-ray Computed Tomography

    NASA Astrophysics Data System (ADS)

    Armstrong, R. T.; Ajo Franklin, J. B.

    2009-12-01

    Biomineralization is a natural subsurface process that upon stimulation can dramatically affect soil mechanics and hydraulics. This work presents the results of a study where synchrotron based X-Ray Computed Microtomography (CMT) is used to investigate temporal cementation dynamics and the spatial distribution of biogenic CaCO3 at the pore-scale, thus, shedding light on pore clogging and contact cementation. To facilitate these studies we have developed a family of flow-through bioreactors (ID 8 mm) which can be scanned continuously during precipitation experiments. The reactor is also equipped with differential pressure transducers to allow measurement of sample permeability. Porosity permeability correlations, cementation morphology, CaCO3 spatial distribution, and bulk cementation are addressed herein. Sporosarcina pasteurii (formally Bacillus pasteurii), our model organism, is a prevalent aerobic, motile, soil microbe with a very active urease enzyme. Hydrolysis of urea by the urease enzyme generates carbonate ions, ammonium and an increase in pH which favors carbonate precipitation if appropriate metal cations (e.g. Ca2+) are available. Brightfield microscope results show that precipitation occurs within close proximity of the cell membrane reducing microbial motility and forming a CaCO3 precipitate with a "fluffy" appearance. Besides providing an aqueous environment favorable for mineralization S. pasteurii also provides nucleation sites on its cell membrane. Since this microbe is very effective at inducing carbonate precipitation over a relativity short time span (2-3 days), it was used exclusively in our experiments. Prior to CMT imaging the feasibility of temporal imaging was investigated. Viable cell counts taken before and after imaging showed that a considerable amount of bacteria survived the monochromatic (30 KeV) X-ray exposure. Cementation experiments initiated with inoculation of the CMT column with microbes and urea media, cells were allowed to

  18. On how X-ray (micro) computed tomography on turbidites can help us unravel paleoflow successions, directions and dynamics

    NASA Astrophysics Data System (ADS)

    Van Daele, Maarten; Cnudde, Veerle; Boone, Marijn; Deprez, Maxim; De Batist, Marc

    2016-04-01

    Even though X-ray computed tomography (CT) is becoming an increasingly widespread technique in many disciplines - among which sedimentology -, applications are still scarce in turbidite research. In the past few years we showed that medical X-ray CT scans of sediment cores can provide a wealth of information about turbidites and especially their internal structures. In Aysén fjord (Chile) as well as several Chilean and Alaskan lakes, we showed that sedimentary structures such as ripples can be used to reconstruct flow directions, as they can be visualized in 3D. When sedimentary structures are absent, fabrics (e.g. grain imbrication) can also be used. However, the resolution of medical X-ray CT scans is usually not sufficient to visualize single grains or clasts inside the sediment cores. Therefore, medical X-ray CT scans do not allow the determination of single grain orientations. Recently, however, subsamples of sediment cores from a Swiss and an Alaskan lake were scanned at the Centre for X-ray Tomography (UGCT, Ghent University) to obtain μCT data with a resolution of 2 μm. The data allows to isolate single grains that are larger than medium silt, determine their grain size, orientation, as well as other parameters. However, all these grains with variable parameters will react differently to certain flow conditions. While mud clasts are often imbricated, coarse silt grains seem to be only oriented parallel to the flow direction. Studying more turbidites with different compositions and comparing with results from modelling studies (analogue and numerical), will allow to better understand the relationship between flow direction, flow dynamics and grain orientation (for each type of particle). From such an improved understanding not only turbidite paleoseismology, but also many other research disciplines related to fluid flow and particle deposition will benefit.

  19. Dynamic computed tomography of the head and neck: differential diagnostic value

    SciTech Connect

    Michael, A.S.; Mafee, M.F.; Valvassori, G.E.; Tan, W.S.

    1985-02-01

    A retrospective review of the dynamic CT studies performed in our institution on head and neck lesions, excluding the brain, was carried out. Five basic types of density vs. time curves were obtained. Dynamic CT scanning is valuable in the differential diagnosis, management, and followup of such cases; its usefulness as an imaging modality in diagnosis and followup of hemangiomas is stressed.

  20. [Computer tomography in acute pyelonephritis].

    PubMed

    Triller, J; Scheidegger, J; Terrier, F

    1983-07-01

    Computer tomography of the kidneys was performed on 30 patients with acute renal infections (acute suppurative pyelonephritis, acute renal abscess, infected cyst, pyelonephrosis, calculus perforation, retroperitoneal abscess). Computer tomography provided more accurate information concerning the extent of the renal and extra-renal inflammatory process than did the urogram or sonogram. This may significantly affect the choice of treatment, particularly concerning the use of drugs or of surgery. Angiography and retrograde pyelography may be used in selected cases, especially where there is a suspicion of acute bacterial nephritis, renal vein thrombosis or ureteric obstruction.

  1. Development and validation of a segmentation-free polyenergetic algorithm for dynamic perfusion computed tomography.

    PubMed

    Lin, Yuan; Samei, Ehsan

    2016-07-01

    Dynamic perfusion imaging can provide the morphologic details of the scanned organs as well as the dynamic information of blood perfusion. However, due to the polyenergetic property of the x-ray spectra, beam hardening effect results in undesirable artifacts and inaccurate CT values. To address this problem, this study proposes a segmentation-free polyenergetic dynamic perfusion imaging algorithm (pDP) to provide superior perfusion imaging. Dynamic perfusion usually is composed of two phases, i.e., a precontrast phase and a postcontrast phase. In the precontrast phase, the attenuation properties of diverse base materials (e.g., in a thorax perfusion exam, base materials can include lung, fat, breast, soft tissue, bone, and metal implants) can be incorporated to reconstruct artifact-free precontrast images. If patient motions are negligible or can be corrected by registration, the precontrast images can then be employed as a priori information to derive linearized iodine projections from the postcontrast images. With the linearized iodine projections, iodine perfusion maps can be reconstructed directly without the influence of various influential factors, such as iodine location, patient size, x-ray spectrum, and background tissue type. A series of simulations were conducted on a dynamic iodine calibration phantom and a dynamic anthropomorphic thorax phantom to validate the proposed algorithm. The simulations with the dynamic iodine calibration phantom showed that the proposed algorithm could effectively eliminate the beam hardening effect and enable quantitative iodine map reconstruction across various influential factors. The error range of the iodine concentration factors ([Formula: see text]) was reduced from [Formula: see text] for filtered back-projection (FBP) to [Formula: see text] for pDP. The quantitative results of the simulations with the dynamic anthropomorphic thorax phantom indicated that the maximum error of iodine concentrations can be reduced from

  2. Interobserver and Intraobserver Reproducibility with Volume Dynamic Contrast Enhanced Computed Tomography (DCE-CT) in Gastroesophageal Junction Cancer.

    PubMed

    Lundsgaard Hansen, Martin; Fallentin, Eva; Axelsen, Thomas; Lauridsen, Carsten; Norling, Rikke; Svendsen, Lars Bo; Nielsen, Michael Bachmann

    2016-02-01

    The purpose of this study was to assess inter- and intra-observer reproducibility of three different analytic methods to evaluate quantitative dynamic contrast-enhanced computed tomography (DCE-CT) measures from gastroesophageal junctional cancer. Twenty-five DCE-CT studies with gastroesophageal junction cancer were selected from a previous longitudinal study. Three radiologists independently reviewed all scans, and one repeated the analysis eight months later for intraobserver analysis. Review of the scans consisted of three analysis methods: (I) Four, fixed small sized regions of interest (2-dimensional (2D) fixed ROIs) placed in the tumor periphery, (II) 2-dimensional regions of interest (2D-ROI) along the tumor border in the tumor center, and (III) 3-dimensional volumes of interest (3D-VOI) containing the entire tumor volume. Arterial flow, blood volume and permeability (k(trans)) were recorded for each observation. Inter- and intra-observer variability were assessed by Intraclass Correlation Coefficient (ICC) and Bland-Altman statistics. Interobserver ICC was excellent for arterial flow (0.88), for blood volume (0.89) and for permeability (0.91) with 3D-VOI analysis. The 95% limits of agreement were narrower for 3D analysis compared to 2D analysis. Three-dimensional volume DCE-CT analysis of gastroesophageal junction cancer provides higher inter- and intra-observer reproducibility with narrower limits of agreement between readers compared to 2D analysis.

  3. SICAT function: anatomical real-dynamic articulation by merging cone beam computed tomography and jaw motion tracking data.

    PubMed

    Hanssen, N; Ruge, S; Kordass, B

    2014-01-01

    Diagnostic imaging and jaw motion tracking are among the most important technologies used to document and assess the functional status of the stomatognathic system and to plan complex prosthetic restorations. However, the two technologies have not been used together until now. This article introduces SICAT Function (SICAT, Bonn, Germany), a new software application that directly combines and merges three-dimensional cone beam computed tomography (CBCT) and electronic jaw motion tracking (JMT) data. The software can also import digital impressions acquired with intraoral scanners and integrate them in functional movement displays. The result is an anatomically precise yet real-dynamic rendering of jaw movement, ready for comprehensive evaluation and analysis. Moreover, changes in the joint space (gap between the condyle and mandibular fossa) at defined mandibular resting positions or during mandibular movements can be directly measured and displayed. Only one CBCT scan is needed for patient-specific assessment of condylar positions (centric and therapeutic), which are displayed together with the joint space. All other positions are derived via correlation with electronic measurements. PMID:24791466

  4. Computed tomography of intramuscular myxoma

    SciTech Connect

    Ekelund, L.; Herrlin, K.; Rydholm, A.

    1982-11-01

    Computed tomography (CT) was performed in seven patients with intramuscular myxoma. All lesions were well demarcated, of homogeneous appearance and attenuation values ranging from 10 to 60 (HU). The tumor size, as estimated at CT, correlated well with the size of the surgical specimen, which is in contrast to the findings in some high grade malignant sarcomas.

  5. X-ray Computed Tomography.

    ERIC Educational Resources Information Center

    Michael, Greg

    2001-01-01

    Describes computed tomography (CT), a medical imaging technique that produces images of transaxial planes through the human body. A CT image is reconstructed mathematically from a large number of one-dimensional projections of a plane. The technique is used in radiological examinations and radiotherapy treatment planning. (Author/MM)

  6. Computed tomography:the details.

    SciTech Connect

    Doerry, Armin Walter

    2007-07-01

    Computed Tomography (CT) is a well established technique, particularly in medical imaging, but also applied in Synthetic Aperture Radar (SAR) imaging. Basic CT imaging via back-projection is treated in many texts, but often with insufficient detail to appreciate subtleties such as the role of non-uniform sampling densities. Herein are given some details often neglected in many texts.

  7. In situ flash x-ray high-speed computed tomography for the quantitative analysis of highly dynamic processes

    NASA Astrophysics Data System (ADS)

    Moser, Stefan; Nau, Siegfried; Salk, Manfred; Thoma, Klaus

    2014-02-01

    The in situ investigation of dynamic events, ranging from car crash to ballistics, often is key to the understanding of dynamic material behavior. In many cases the important processes and interactions happen on the scale of milli- to microseconds at speeds of 1000 m s-1 or more. Often, 3D information is necessary to fully capture and analyze all relevant effects. High-speed 3D-visualization techniques are thus required for the in situ analysis. 3D-capable optical high-speed methods often are impaired by luminous effects and dust, while flash x-ray based methods usually deliver only 2D data. In this paper, a novel 3D-capable flash x-ray based method, in situ flash x-ray high-speed computed tomography is presented. The method is capable of producing 3D reconstructions of high-speed processes based on an undersampled dataset consisting of only a few (typically 3 to 6) x-ray projections. The major challenges are identified, discussed and the chosen solution outlined. The application is illustrated with an exemplary application of a 1000 m s-1 high-speed impact event on the scale of microseconds. A quantitative analysis of the in situ measurement of the material fragments with a 3D reconstruction with 1 mm voxel size is presented and the results are discussed. The results show that the HSCT method allows gaining valuable visual and quantitative mechanical information for the understanding and interpretation of high-speed events.

  8. Cardiac Computed Tomography (Multidetector CT, or MDCT)

    MedlinePlus

    ... High Blood Pressure Tools & Resources Stroke More Cardiac Computed Tomography (Multidetector CT, or MDCT) Updated:Sep 3,2015 ... facts MDCT is a very fast type of computed tomography (CT) scan. MDCT creates pictures of the healthy ...

  9. Using Micro-Computed Tomography to Evaluate the Dynamics of Orthodontically Induced Root Resorption Repair in a Rat Model

    PubMed Central

    Yang, Fengxue; Wei, Shicheng; Dai, Hongwei

    2016-01-01

    Objective To observe dynamic changes in root resorption repair, tooth movement relapse and alveolar bone microstructure following the application of orthodontic force. Materials and Methods Forces of 20 g, 50 g or 100 g were delivered to the left maxillary first molars of fifteen 10-week-old rats for 14 days. Each rat was subjected to micro-computed tomography scanning at 0, 3, 7, 10, 14, 28 and 42 days after force removal. The root resorption crater volume, tooth movement relapse and alveolar bone microarchitecture were measured at each time point. Results From day 3 to day 14, the root resorption volume decreased significantly in each group. In the 20-g force group, the root resorption volume gradually stabilized after 14 days, whereas in the 50-g and 100-g force groups, it stabilized after 28 days. In all groups, tooth movement relapsed significantly from day 0 to day 14 and then remained stable. From day 3 to day 10, the 20-g group exhibited faster relapse than the 50-g and 100-g groups. In all groups, the structure model index and trabecular separation decreased slowly from day 0 to day 10 and eventually stabilized. Trabecular number increased slowly from day 0 to day 7 and then stabilized. Conclusions The initial stage of root resorption repair did not change significantly and was followed by a dramatic repair period before stabilizing. The most serious tooth movement relapse occurred immediately after the appliance was removed, and then the tooth completely returned to the original position. PMID:26930605

  10. Pediatric cranial computed tomography

    SciTech Connect

    Yamada, H.

    1984-01-01

    The introduction of CT in the investigation of intercranial pathology has revolutionized the approach to clinical neurological and neurosurgical practice. This book applies the advances of cranial CT to the pediatric patient. The test is divided into two sections. The first portion describes the practical methodology, anatomy and normal and abnormal CT scan appearance, including high or low density lesions, cystic lesions and ventricular or subarachnoid space dilation. The characteristic scans for various neurological diseases are presented and discussed. The author has given special attention to the CT diagnosis of congenital malformations and cerebral neoplasms. Partial Contents: Normal Computed Tomographic Anatomy/ High Density Lesions/Low Density Lesions/Cystic Lesions; Supratentorial/Cystic Lesions; Infratentorial/Increased Head Circumference/Increased Ventricular Size/Small Ventricular Size/Cranial Lesions/Spinal Lesions/CT Cisternography/Part II CT in Neonates/Congenital Craniocerebral Malformations/Hydrocephalus/Craniosynostosis/Head Trauma/Cerebrovascular Lesions/Intracranial Lesions/Seizure Disorders/Intracranial and Other Chronic Neurological Disorders.

  11. Computed tomography of the abdomen.

    PubMed

    Leslie, E V; Panaro, V A; Alker, G J; Oh, Y S

    1980-01-01

    In a few short years, computed tomography has become an important diagnostic procedure in the examination of the abdomen and pelvis. Its forte lies in its ability to provide cross-sectional views of excellent anatomical detail. Imaging of deep-seated structures such as the pancreas, adrenal glands, and enlarged retroperitoneal lymph nodes is now possible. The ability to distinguish small variations in tissue density enables the radiologist to evaluate the texture of solid structures, and to differentiate them from cysts or abscesses. The addition of contrast enhancement makes it possible to determine the vascularity of a lesson. The major limitation of CT is poorer delineation of structures in thin patients, and in patients in whom voluntary and involuntary motion cannot be interrupted. Computed tomography is compared with other complementary imaging procedures to include sonography, radionuclide imaging, and conventional radiograph procedures. It has replaced invasive diagnostic procedures in many instances. In a given situation, one or more imaging modalities may be appropriate.

  12. Computed tomography of gynecologic diseases

    SciTech Connect

    Gross, B.H.; Moss, A.A.; Mihara, K.; Goldberg, H.I.; Glazer, G.M.

    1983-10-01

    Although computed tomography (CT) provides superb images of all areas of the body, sonography, because of its lack of ionizing radiation and its real-time and multiplanar capacities, has become the preferred initial method of evaluating the female pelvis. This has resulted in a relative paucity of information in the literature concerning CT features of benign pelvic disorders in particular and prompted the authors to review our experience with third-generation CT scanning of the uterus and ovaries.

  13. Cranial computed tomography and MRI

    SciTech Connect

    Lee, S.H.; Rao, K.C.V.G.

    1987-01-01

    This book appears to be a hybrid between an atlas and a text. The second edition attempts to depict the current status of both computed tomography (CT) and magnetic resonance (MR) imaging in neuroradiology. Although only the final chapter of the book is completely devoted to cranial MR imaging, MR images are scattered throughout various other chapters. There is coverage of the major anatomic and pathophysiologic entities. There are 17 chapters with images, tables, and diagrams.

  14. Hermaphroditism demonstrated by computed tomography

    SciTech Connect

    Gale, M.E.

    1983-07-01

    The categorization of disorders of gender differentiation is based on chromosome analysis, physical examination, gonadal histology, and endocrine evaluation. In most cases of hermaphroditism, radiologic studies have been limited to assessment of associated urinary tract anomalies before surgical revconstruction. Noninvasive evaluation with computed tomography (CT) or sonography is potentially useful for investigation of internal pelvic anatomy in these cases. A case report of a 65-year-old man is reported. (KRM)

  15. Clinical application of 320-row multidetector computed tomography for a dynamic three-dimensional vascular study: imaging findings and initial experience.

    PubMed

    Nagamatsu, Shogo; Nakagawa, Masahiro; Kayano, Shuji; Koizumi, Takuya; Akazawa, Satoshi; Onitsuka, Tetsuro; Iida, Yoshiyuki; Endo, Masahiro; Nakaya, Yoshihiro; Urikura, Atsushi

    2010-10-01

    The 320-row multidetector computed tomography (MDCT) is now used by both cardiologists and neurosurgeons. It enables dynamic 3D-CT angiography, because the wide-area detector eliminates helical scanning, thus achieving very fast scanning times for single 3D-CT volume data. Some microvascular surgeons are familiar with 64-row MDCT for perforator studies, but there are few reports of studies using 320-row MDCT. This MDCT system was used to follow the dynamic blood flow of small vessels. It is considered to have a great potential in the clinical field of microvascular surgery. PMID:20399163

  16. Computed tomography of fibrous dysplasia

    SciTech Connect

    Daffner, R.H.; Kirks, D.R.; Gehweiler, J.A. Jr.; Heaston, D.K.

    1982-11-01

    Skeletal fibrous dysplasia produces changes that are usually readily recognized on plain radiographs. Occasionally, routine radiography may not demonstrate the characteristic appearance of the disease. The density of abormal bone in craniofacial fibrous dysplasia may preclude adequate assessment of areas where soft-tissue impingement may occur. Computed tomography (CT) is useful in demonstrating the amorphous ''ground-glass'' texture of the lesion and in defining the extent of craniofacial disease including impingement upon orbital structures. CT was useful in five patients with fibrous dysplasia in whom the nature or extent of involvement was not entirely clear.

  17. Dual-energy computed tomography.

    PubMed

    Furlow, Bryant

    2015-01-01

    Dual-energy computed tomography (DECT) yields precise anatomic and functional images by exploiting differences in the interactions of high- and low-energy photon spectra with different tissues' and materials' atomic components to more precisely differentiate the chemistry of tissues and disease processes than is possible with traditional single-energy CT scan acquisitions. This article introduces the history of DECT, its physical basis, scanner designs, radiation dose considerations, and postprocessing techniques. DECT's clinical applications also are described, and this relatively new imaging modality's clinical limitations and future prospects are discussed.

  18. Computed tomography of parosteal osteosarcoma

    SciTech Connect

    Hudson, T.M.; Springfield, D.S.; Benjamin, M.; Bertoni, F.; Present, D.A.

    1985-05-01

    Twelve patients with parosteal osteosarcomas were evaluated by computed tomography (CT). CT accurately defined the extent of the tumors for purposes of surgical planning, although tumor bone often could not be distinguished from thickened host bone. Nine tumors invaded the medullary cavity, a feature that implies a poorer prognosis when the tumor also contains high-grade areas. Six CT studies accurately detected the medullary invasion, but three did not. Lucent areas within dense tumors contained either benign tissue or high- or low-grade tumor; CT did not differentiate among these different tissues. CT also did not reveal small satellite nodules of tumor beyond the main tumor mass.

  19. Computed tomography of the genitourinary tract.

    PubMed

    Stanley, R J; Sagel, S S; Fair, W R

    1978-06-01

    Eighteen months of experience with computed body tomography have revealed that this radiologic modality is useful in the diagnostic evaluation and management of urologic patients. Renal masses, perirenal lesions, poorly functioning kidneys, pelvic tumors and associated retroperitoneal nodal spread and other diagnostic problems related to the urinary tract have been imaged successfully with computed body tomography. Accuracy is high in the differentiation of benign renal cysts from renal neoplasms. Tumor staging and computed body tomography is being explored currently.

  20. Dynamic enhancement patterns of intrahepatic cholangiocarcinoma in cirrhosis on contrast-enhanced computed tomography: risk of misdiagnosis as hepatocellular carcinoma.

    PubMed

    Li, Rui; Cai, Ping; Ma, Kuan-Sheng; Ding, Shi-Yi; Guo, De-Yu; Yan, Xiao-Chu

    2016-01-01

    This study aimed to assess the features of intrahepatic cholangiocarcinoma (ICC) at computerized tomography (CT) and verify the risk of misdiagnosis of ICC as hepatocellular carcinoma (HCC) in cirrhosis. CT appearances of 98 histologically confirmed ICC nodules from 84 cirrhotic patients were retrospectively reviewed, taking into consideration the pattern and dynamic contrast uptake during the arterial, portal venous and delayed phases. During the arterial phase, 53 nodules (54.1%) showed peripheral rim-like enhancement, 35 (35.7%) hyperenhancement, 9 (9.2%) hypoenhancement and 1 (1.0%) isoenhancement. The ICC nodules showed heterogeneous dynamic contrast patterns, being progressive enhancement in 35 nodules (35.7%), stable enhancement in 28 nodules (28.6%), wash-in and wash-out pattern in 15 nodules (15.3%) and all other enhancement patterns in 20 nodules (20.4%). There were no significant differences in the dynamic vascular patterns of ICC according to nodule size (p > 0.05). ICC in cirrhosis has varied enhancement patterns at contrast-enhanced multiphase multidetector CT. Though the majority of ICC did not display typical radiological hallmarks of HCC, if dynamic CT scan was used as the sole modality for the non-invasive diagnosis of nodules in cirrhosis, the risk of misdiagnosis of ICC for HCC is not negligible.

  1. Computer tomography imaging of fast plasmachemical processes

    SciTech Connect

    Denisova, N. V.; Katsnelson, S. S.; Pozdnyakov, G. A.

    2007-11-15

    Results are presented from experimental studies of the interaction of a high-enthalpy methane plasma bunch with gaseous methane in a plasmachemical reactor. The interaction of the plasma flow with the rest gas was visualized by using streak imaging and computer tomography. Tomography was applied for the first time to reconstruct the spatial structure and dynamics of the reagent zones in the microsecond range by the maximum entropy method. The reagent zones were identified from the emission of atomic hydrogen (the H{sub {alpha}} line) and molecular carbon (the Swan bands). The spatiotemporal behavior of the reagent zones was determined, and their relation to the shock-wave structure of the plasma flow was examined.

  2. [Computer tomography of sports injuries].

    PubMed

    Reiser, M; Rupp, N

    1984-01-01

    Computed tomography (CT) provides axial slices plane and shows excellent details of bones and different soft tissues, favoring its use in traumatic lesions caused by sporting activities. Complex anatomical structures such as the shoulder, the vertebral column, the pelvis, the knee, the tarsal and carpal bones are often better recognized in detail than by conventional radiography. Fracture lines, localization of bone fragments and involvement of soft tissues are clearly demonstrated. Luxations and bone changes leading to luxations can be shown. CT arthrography provides for the first time a direct visualization of joint cartilage and of cruciate ligaments in the knee joint, so traumatic lesions such as chondropathia patellae or rupture of the cruciate ligaments are shown with a high degree of reliability.

  3. Single photon emission computed tomography

    SciTech Connect

    Piez, C.W. Jr.; Holman, B.L.

    1985-07-01

    Single photon emission computed tomography (SPECT) is becoming an increasingly important part of routine clinical nuclear medicine. By providing tomographic reconstructions in multiple planes through the patient, SPECT expands the clinical applications in nuclear medicine as well as providing better contrast, edge definition and separation of target from background activities. Imaging techniques have been developed for the evaluation of regional cerebral blood flow using radiolabeled amines. Thus, cerebral functional imaging can be used in the diagnosis of acute cerebral infarction, cerebral vascular disease, dementia and epilepsy. SPECT plays a complementary role in the evaluation of coronary artery disease, particularly when it is coupled with thallium-201 and exercise testing. SPECT extends our diagnostic capabilities in additional areas, such as liver and bone scintigraphy as well as tumor imaging with gallium-67.

  4. Computed tomography of cryogenic cells

    SciTech Connect

    Schneider, Gerd; Anderson, E.; Vogt, S.; Knochel, C.; Weiss, D.; LeGros, M.; Larabell, C.

    2001-08-30

    Due to the short wavelengths of X-rays and low numerical aperture of the Fresnel zone plates used as X-ray objectives, the depth of field is several microns. Within the focal depth, imaging a thick specimen is to a good approximation equivalent to projecting the specimen absorption. Therefore, computed tomography based on a tilt series of X-ray microscopic images can be used to reconstruct the local linear absorption coefficient and image the three-dimensional specimen structure. To preserve the structural integrity of biological objects during image acquisition, microscopy is performed at cryogenic temperatures. Tomography based on X-ray microscopic images was applied to study the distribution of male specific lethal 1 (MSL-1), a nuclear protein involved in dosage compensation in Drosophila melanogaster, which ensures that males with single X chromosome have the same amount of most X-linked gene products as females with two X chromosomes. Tomographic reconstructions of X-ray microscopic images were used to compute the local three-dimensional linear absorption coefficient revealing the arrangement of internal structures of Drosophila melanogaster cells. Combined with labelling techniques, nanotomography is a new technique to study the 3D distribution of selected proteins inside whole cells. We want to improve this technique with respect to resolution and specimen preparation. The resolution in the reconstruction can be significantly improved by reducing the angular step size to collect more viewing angles, which requires an automated data acquisition. In addition, fast-freezing with liquid ethane instead of cryogenic He gas will be applied to improve the vitrification of the hydrated samples. We also plan to apply cryo X-ray nanotomography in order to study different types of cells and their nuclear protein distributions.

  5. [Computed tomography and cranial paleoanthropology].

    PubMed

    Cabanis, Emmanuel Alain; Badawi-Fayad, Jackie; Iba-Zizen, Marie-Thérèse; Istoc, Adrian; de Lumley, Henry; de Lumley, Marie-Antoinette; Coppens, Yves

    2007-06-01

    Since its invention in 1972, computed tomography (C.T.) has significantly evolved. With the advent of multi-slice detectors (500 times more sensitive than conventional radiography) and high-powered computer programs, medical applications have also improved. CT is now contributing to paleoanthropological research. Its non-destructive nature is the biggest advantage for studying fossil skulls. The second advantage is the possibility of image analysis, storage, and transmission. Potential disadvantages include the possible loss of files and the need to keep up with rapid technological advances. Our experience since the late 1970s, and a recent PhD thesis, led us to describe routine applications of this method. The main contributions of CT to cranial paleoanthropology are five-fold: --Numerical anatomy with rapid acquisition and high spatial resolution (helicoidal and multidetector CT) offering digital storage and stereolithography (3D printing). --Numerical biometry (2D and 3D) can be used to create "normograms" such as the 3D craniofacial reference model used in maxillofacial surgery. --Numerical analysis offers thorough characterization of the specimen and its state of conservation and/or restoration. --From "surrealism" to virtual imaging, anatomical structures can be reconstructed, providing access to hidden or dangerous zones. --The time dimension (4D imaging) confers movement and the possibility for endoscopic simulation and internal navigation (see Iconography). New technical developments will focus on data processing and networking. It remains our duty to deal respectfully with human fossils. PMID:18402165

  6. Radiological protection in computed tomography and cone beam computed tomography.

    PubMed

    Rehani, M M

    2015-06-01

    The International Commission on Radiological Protection (ICRP) has sustained interest in radiological protection in computed tomography (CT), and ICRP Publications 87 and 102 focused on the management of patient doses in CT and multi-detector CT (MDCT) respectively. ICRP forecasted and 'sounded the alarm' on increasing patient doses in CT, and recommended actions for manufacturers and users. One of the approaches was that safety is best achieved when it is built into the machine, rather than left as a matter of choice for users. In view of upcoming challenges posed by newer systems that use cone beam geometry for CT (CBCT), and their widened usage, often by untrained users, a new ICRP task group has been working on radiological protection issues in CBCT. Some of the issues identified by the task group are: lack of standardisation of dosimetry in CBCT; the false belief within the medical and dental community that CBCT is a 'light', low-dose CT whereas mobile CBCT units and newer applications, particularly C-arm CT in interventional procedures, involve higher doses; lack of training in radiological protection among clinical users; and lack of dose information and tracking in many applications. This paper provides a summary of approaches used in CT and MDCT, and preliminary information regarding work just published for radiological protection in CBCT.

  7. Fundamentals and recent advances in X-ray micro computed tomography (microCT) applied on thermal-fluid dynamics and multiphase flows

    NASA Astrophysics Data System (ADS)

    Santini, Maurizio

    2015-11-01

    X-ray computed tomography (CT) is a well-known technique nowadays, since its first practical application by Sir. G. Hounsfield (Nobel price for medicine 1979) has continually benefited from optimising improvements, especially in medical applications. Indeed, also application of CT in various engineering research fields provides fundamental informations on a wide range of applications, considering that the technique is not destructive, allowing 3D visualization without perturbation of the analysed material. Nowadays, it is technologically possible to design and realize an equipment that achieve a micrometric resolution and even improve the sensibility in revealing differences in materials having very radiotransparency, allowing i.e. to distinguish between different fluids (with different density) or states of matter (like with two-phase flows). At the University of Bergamo, a prototype of an X-ray microCT system was developed since 2008, so being fully operative from 2012, with specific customizations for investigations in thermal-fluid dynamics and multiphase flow researches. A technical session held at the UIT International Conference in L'Aquila (Italy), at which this paper is referring, has presented some microCT fundamentals, to allow the audience to gain basics to follow the “fil-rouge” that links all the instrumentation developments, till the recent applications. Hereinafter are reported some applications currently developed at Bergamo University at the X-ray computed micro-tomography laboratory.

  8. Computed tomography using synchrotron radiation

    SciTech Connect

    Thompson, A.C.; Llacer, J.; Finman, L.C.; Hughes, E.B.; Otis, J.N.; Wilson, S.; Zeman, H.D.

    1983-09-01

    X-ray computed tomography (CT) is a widely used method of obtaining cross-sectional views of objects. The high intensity, natural collimation, monochromaticity and energy tunability of synchrotron x-ray sources could potentially be used to provide CT images of improved quality. The advantages of these systems would be that images could be produced more rapidly with better spatial resolution and reduced beam artifacts. In addition, images, in some cases, could be acquired with elemental sensitivity. As a demonstration of the capability of such a system, CT images were obtained of four slices of an excised pig heart in which the arteries and the cardiac chambers were filled with an iodinated medium. Images were taken with incident x-rays tuned successively to energies just above and below the iodine K edge. Iodine specific images were obtained by logarithmically subtracting the low energy image data from the high energy data and then reconstructing the image. CT imaging using synchrotron radiation may become a convenient and non-destructive method of imaging samples difficult to study by other methods.

  9. Direct coronal body computed tomography.

    PubMed

    van Waes, P F; Zonneveld, F W

    1982-02-01

    Three patient positioning technique have been developed for direct coronal computed tomography (CT) of the body, covering the complete torso: position A, to study pelvis, including retroperitoneal space and lower abdomen; position B, to study upper abdomen and lower chest; and position C, to study upper chest, including neck and posterior fossa. In comparison with multiplanar reformatting (MPR), direct coronal CT has three basic advantages: (a) image quality is improved as a result of a lack of partial volume averaging and patient motion disturbance; (b) the direct coronal planes can be truly parallel to the spinal axis, due to stretching of the lordotic segments of the spine; and (c) examination time is reduced, since a large number of overlapping slices and time consuming MPR effort are not required. Direct coronal CT of the body has been carried out in more than 600 cases and was often uniquely informative. In our institution, use of MPR CT is now restricted to small volumes and/or disabled patients.

  10. Mantle dynamics and seismic tomography.

    PubMed

    Tanimoto, T; Lay, T

    2000-11-01

    Three-dimensional imaging of the Earth's interior, called seismic tomography, has achieved breakthrough advances in the last two decades, revealing fundamental geodynamical processes throughout the Earth's mantle and core. Convective circulation of the entire mantle is taking place, with subducted oceanic lithosphere sinking into the lower mantle, overcoming the resistance to penetration provided by the phase boundary near 650-km depth that separates the upper and lower mantle. The boundary layer at the base of the mantle has been revealed to have complex structure, involving local stratification, extensive structural anisotropy, and massive regions of partial melt. The Earth's high Rayleigh number convective regime now is recognized to be much more interesting and complex than suggested by textbook cartoons, and continued advances in seismic tomography, geodynamical modeling, and high-pressure-high-temperature mineral physics will be needed to fully quantify the complex dynamics of our planet's interior.

  11. Interlaced X-ray diffraction computed tomography

    PubMed Central

    Vamvakeros, Antonios; Jacques, Simon D. M.; Di Michiel, Marco; Senecal, Pierre; Middelkoop, Vesna; Cernik, Robert J.; Beale, Andrew M.

    2016-01-01

    An X-ray diffraction computed tomography data-collection strategy that allows, post experiment, a choice between temporal and spatial resolution is reported. This strategy enables time-resolved studies on comparatively short timescales, or alternatively allows for improved spatial resolution if the system under study, or components within it, appear to be unchanging. The application of the method for studying an Mn–Na–W/SiO2 fixed-bed reactor in situ is demonstrated. Additionally, the opportunities to improve the data-collection strategy further, enabling post-collection tuning between statistical, temporal and spatial resolutions, are discussed. In principle, the interlaced scanning approach can also be applied to other pencil-beam tomographic techniques, like X-ray fluorescence computed tomography, X-ray absorption fine structure computed tomography, pair distribution function computed tomography and tomographic scanning transmission X-ray microscopy. PMID:27047305

  12. Nondestructive computed tomography for pit inspections

    SciTech Connect

    Martz, H.; Logan, C.; Haskins, J.; Johansson, E.; Perkins, D.; Hernandez, J.M.; Schneberk, D.; Dolan, K.

    1997-02-07

    Objective is to develop new approaches to electronically capture digital radiography and computed tomography images at high x-ray energies to satisfy spatial and contrast requirements for inspection of high-density weapons components.

  13. Computed tomography of the rectosigmoid region.

    PubMed

    Dixon, A K

    1996-05-01

    Knowledge of the anatomy and embryology of the rectosigmoid region is useful for the correct interpretation of computed tomography in this region. The appearances and differential diagnoses of some of the common conditions affecting this region are presented and discussed.

  14. Single Photon Emission Computed Tomography (SPECT)

    MedlinePlus

    ... High Blood Pressure Tools & Resources Stroke More Single Photon Emission Computed Tomography (SPECT) Updated:Sep 11,2015 ... Persantine) or dobutamine. The tests may take between 2 and 2 1/2 hours. What happens after ...

  15. Computed Tomography For Internal Inspection Of Castings

    NASA Technical Reports Server (NTRS)

    Hanna, Timothy L.

    1995-01-01

    Computed tomography used to detect internal flaws in metal castings before machining and otherwise processing them into finished parts. Saves time and money otherwise wasted on machining and other processing of castings eventually rejected because of internal defects. Knowledge of internal defects gained by use of computed tomography also provides guidance for changes in foundry techniques, procedures, and equipment to minimize defects and reduce costs.

  16. Computed Tomography of Pancreatitis and Pancreatic Cancer.

    PubMed

    Furlow, Bryant

    2015-01-01

    Pancreatic disease often is asymptomatic until tissue damage and complications occur or until malignancies have reached advanced stages and have metastasized. Contrast-enhanced multidetector computed tomography plays a central role in diagnosing, staging, and treatment planning for pancreatitis and pancreatic cancer. This article introduces the functional anatomy of the pancreas and common bile duct and the epidemiology, pathobiology, and computed tomography imaging of pancreatitis, calculi, and pancreatic cancer.

  17. Dynamics of contrast enhancement in delayed computed tomography of brain tumors: tissue-blood ratio and differential diagnosis

    SciTech Connect

    Takeda, N.; Tanaka, R.; Naki, O.; Ueki, K.

    1982-03-01

    Thirty-one patients with brain tumors were studied by delayed computed tomographic (CT) scanning performed one and two hours after intravenous administration of contrast medium. Dynamics of contrast enhancement in the lesion were analyzed quantitatively and qualitatively by calculating the tissue-blood ratio (TBR) at each scan, and are expressed as relative TBR (R-TBR). The R-TBRs obtained two hours after the first contrast-enhanced scan were found to be most useful in diagnosis, and were classified into three groups: less than 1.5 (Class I), 1.5 to 3.0 (Class II), and more than 3.0 (Class III). In the glioma group, seven of eight anaplastic gliomas were Class III and all of three anaplastic astrocytomas were Class II. All of seven meningiomas were Class I. Four of five pituitary adenomas were Class II. Three of four neurinomas were Class III. This method is potentially useful in differential diagnosis of some brain tumors.

  18. Evaluation of an asymmetric stent patch design for a patient specific intracranial aneurysm using computational fluid dynamic (CFD) calculations in the computed tomography (CT) derived lumen

    NASA Astrophysics Data System (ADS)

    Kim, Minsuok; Ionita, Ciprian; Tranquebar, Rekha; Hoffmann, Kenneth R.; Taulbee, Dale B.; Meng, Hui; Rudin, Stephen

    2006-03-01

    Stenting may provide a new, less invasive therapeutic option for cerebral aneurysms. However, a conventional porous stent may be insufficient in modifying the blood flow for clinical aneurysms. We designed an asymmetric stent consisting of a low porosity patch welded onto a porous stent for an anterior cerebral artery aneurysm of a specific patient geometry to block the strong inflow jet. To evaluate the effect of the patch on aneurysmal flow dynamics, we "virtually" implanted it into the patient's aneurysm geometry and performed Computational Fluid Dynamics (CFD) analysis. The patch was computationally deformed to fit into the vessel lumen segmented from the patient CT reconstructions. After the flow calculations, a patch with the same design was fabricated using laser cutting techniques and welded onto a commercial porous stent, creating a patient-specific asymmetric stent. This stent was implanted into a phantom, which was imaged with X-ray angiography. The hemodynamics of untreated and stented aneurysms were compared both computationally and experimentally. It was found from CFD of the patient aneurysm that the asymmetric stent effectively blocked the strong inflow jet into the aneurysm and eliminated the flow impingement on the aneurysm wall at the dome. The impact zone with elevated wall shear stress was eliminated, the aneurysmal flow activity was substantially reduced, and the flow was considerably reduced. Experimental observations corresponded well qualitatively with the CFD results. The demonstrated asymmetric stent could lead to a new minimally invasive image guided intervention to reduce aneurysm growth and rupture.

  19. Panoramic cone beam computed tomography

    SciTech Connect

    Chang Jenghwa; Zhou Lili; Wang Song; Clifford Chao, K. S.

    2012-05-15

    Purpose: Cone-beam computed tomography (CBCT) is the main imaging tool for image-guided radiotherapy but its functionality is limited by a small imaging volume and restricted image position (imaged at the central instead of the treatment position for peripheral lesions to avoid collisions). In this paper, the authors present the concept of ''panoramic CBCT,'' which can image patients at the treatment position with an imaging volume as large as practically needed. Methods: In this novel panoramic CBCT technique, the target is scanned sequentially from multiple view angles. For each view angle, a half scan (180 deg. + {theta}{sub cone} where {theta}{sub cone} is the cone angle) is performed with the imaging panel positioned in any location along the beam path. The panoramic projection images of all views for the same gantry angle are then stitched together with the direct image stitching method (i.e., according to the reported imaging position) and full-fan, half-scan CBCT reconstruction is performed using the stitched projection images. To validate this imaging technique, the authors simulated cone-beam projection images of the Mathematical Cardiac Torso (MCAT) thorax phantom for three panoramic views. Gaps, repeated/missing columns, and different exposure levels were introduced between adjacent views to simulate imperfect image stitching due to uncertainties in imaging position or output fluctuation. A modified simultaneous algebraic reconstruction technique (modified SART) was developed to reconstruct CBCT images directly from the stitched projection images. As a gold standard, full-fan, full-scan (360 deg. gantry rotation) CBCT reconstructions were also performed using projection images of one imaging panel large enough to encompass the target. Contrast-to-noise ratio (CNR) and geometric distortion were evaluated to quantify the quality of reconstructed images. Monte Carlo simulations were performed to evaluate the effect of scattering on the image quality and

  20. Experimental polyethylene-hydroxyapatite carrier-based endodontic system: an in vitro study on dynamic thermomechanical properties, sealing ability, and measurements of micro-computed tomography voids.

    PubMed

    Alhashimi, Raghad A; Mannocci, Francesco; Sauro, Salvatore

    2016-06-01

    The dynamic thermomechanical properties, sealing ability, and voids formation of an experimental obturation hydroxyapatite-reinforced polyethylene (HA/PE) composite/carrier system were investigated and compared with those of a commercial system [GuttaCore (GC)]. The HA/PE system was specifically designed using a melt-extrusion process. The viscoelastic properties of HA/PE were determined using a dynamic thermomechanical analyser. Human single-rooted teeth were endodontically instrumented and obturated using HA/PE or GC systems, and then sealing ability was assessed using a fluid filtration system. In addition, micro-computed tomography (μCT) was used to quantify apparent voids within the root-canal space. The data were statistically analysed using one-way anova and post hoc tests. The HA/PE composite exhibited important modulus and damping changes with an increase of temperature. The HA/PE system was more flexible than GC as the modulus of GC appeared to be significantly higher than that of HA/PE as a result of the high positive glass transition temperature (Tg ). However, HA/PE and GC presented similar sealing abilities. In conclusion, because sealing ability and voids formation were comparable between the tested materials, the experimental HA/PE system may be considered a suitable alternative material for root-canal obturation. Moreover, HA/PE possesses specific viscoelastic behaviour and lower melting points, which may facilitate root-canal retreatments.

  1. Experimental polyethylene-hydroxyapatite carrier-based endodontic system: an in vitro study on dynamic thermomechanical properties, sealing ability, and measurements of micro-computed tomography voids.

    PubMed

    Alhashimi, Raghad A; Mannocci, Francesco; Sauro, Salvatore

    2016-06-01

    The dynamic thermomechanical properties, sealing ability, and voids formation of an experimental obturation hydroxyapatite-reinforced polyethylene (HA/PE) composite/carrier system were investigated and compared with those of a commercial system [GuttaCore (GC)]. The HA/PE system was specifically designed using a melt-extrusion process. The viscoelastic properties of HA/PE were determined using a dynamic thermomechanical analyser. Human single-rooted teeth were endodontically instrumented and obturated using HA/PE or GC systems, and then sealing ability was assessed using a fluid filtration system. In addition, micro-computed tomography (μCT) was used to quantify apparent voids within the root-canal space. The data were statistically analysed using one-way anova and post hoc tests. The HA/PE composite exhibited important modulus and damping changes with an increase of temperature. The HA/PE system was more flexible than GC as the modulus of GC appeared to be significantly higher than that of HA/PE as a result of the high positive glass transition temperature (Tg ). However, HA/PE and GC presented similar sealing abilities. In conclusion, because sealing ability and voids formation were comparable between the tested materials, the experimental HA/PE system may be considered a suitable alternative material for root-canal obturation. Moreover, HA/PE possesses specific viscoelastic behaviour and lower melting points, which may facilitate root-canal retreatments. PMID:27041355

  2. Computed Tomography: Image and Dose Assessment

    NASA Astrophysics Data System (ADS)

    Valencia-Ortega, F.; Ruiz-Trejo, C.; Rodríguez-Villafuerte, M.; Buenfil, A. E.; Mora-Hernández, L. A.

    2006-09-01

    In this work an experimental evaluation of image quality and dose imparted during a computed tomography study in a Public Hospital in Mexico City is presented; The measurements required the design and construction of two phantoms at the Institute of Physics, UNAM, according to the recommendations of American Association of Physicists in Medicine (AAPM). Image assessment was performed in terms the spatial resolution and image contrast. Dose measurements were carried out using LiF: Mg,Ti (TLD-100) dosemeters and pencil-shaped ionisation chamber; The results for a computed tomography head study in single and multiple detector modes are presented.

  3. Pictorial review: electron beam computed tomography and multislice spiral computed tomography for cardiac imaging.

    PubMed

    Lembcke, Alexander; Hein, Patrick A; Dohmen, Pascal M; Klessen, Christian; Wiese, Till H; Hoffmann, Udo; Hamm, Bernd; Enzweiler, Christian N H

    2006-03-01

    Electron beam computed tomography (EBCT) revolutionized cardiac imaging by combining a constant high temporal resolution with prospective ECG triggering. For years, EBCT was the primary technique for some non-invasive diagnostic cardiac procedures such as calcium scoring and non-invasive angiography of the coronary arteries. Multislice spiral computed tomography (MSCT) on the other hand significantly advanced cardiac imaging through high volume coverage, improved spatial resolution and retrospective ECG gating. This pictorial review will illustrate the basic differences between both modalities with special emphasis to their image quality. Several experimental and clinical examples demonstrate the strengths and limitations of both imaging modalities in an intraindividual comparison for a broad range of diagnostic applications such as coronary artery calcium scoring, coronary angiography including stent visualization as well as functional assessment of the cardiac ventricles and valves. In general, our examples indicate that EBCT suffers from a number of shortcomings such as limited spatial resolution and a low contrast-to-noise ratio. Thus, EBCT should now only be used in selected cases where a constant high temporal resolution is a crucial issue, such as dynamic (cine) imaging. Due to isotropic submillimeter spatial resolution and retrospective data selection MSCT seems to be the non-invasive method of choice for cardiac imaging in general, and for assessment of the coronary arteries in particular. However, technical developments are still needed to further improve the temporal resolution in MSCT and to reduce the substantial radiation exposure. PMID:16427236

  4. Performance evaluation of an improved optical computed tomography polymer gel dosimeter system for 3D dose verification of static and dynamic phantom deliveries

    SciTech Connect

    Lopatiuk-Tirpak, O.; Langen, K. M.; Meeks, S. L.; Kupelian, P. A.; Zeidan, O. A.; Maryanski, M. J.

    2008-09-15

    The performance of a next-generation optical computed tomography scanner (OCTOPUS-5X) is characterized in the context of three-dimensional gel dosimetry. Large-volume (2.2 L), muscle-equivalent, radiation-sensitive polymer gel dosimeters (BANG-3) were used. Improvements in scanner design leading to shorter acquisition times are discussed. The spatial resolution, detectable absorbance range, and reproducibility are assessed. An efficient method for calibrating gel dosimeters using the depth-dose relationship is applied, with photon- and electron-based deliveries yielding equivalent results. A procedure involving a preirradiation scan was used to reduce the edge artifacts in reconstructed images, thereby increasing the useful cross-sectional area of the dosimeter by nearly a factor of 2. Dose distributions derived from optical density measurements using the calibration coefficient show good agreement with the treatment planning system simulations and radiographic film measurements. The feasibility of use for motion (four-dimensional) dosimetry is demonstrated on an example comparing dose distributions from static and dynamic delivery of a single-field photon plan. The capability to visualize three-dimensional dose distributions is also illustrated.

  5. Dynamic detector offsets for field of view extension in C-arm computed tomography with application to weight-bearing imaging

    PubMed Central

    Herbst, Magdalena; Schebesch, Frank; Berger, Martin; Choi, Jang-Hwan; Fahrig, Rebecca; Hornegger, Joachim; Maier, Andreas

    2015-01-01

    Purpose: In C-arm computed tomography (CT), the field of view (FOV) is often not sufficient to acquire certain anatomical structures, e.g., a full hip or thorax. Proposed methods to extend the FOV use a fixed detector displacement and a 360° scan range to double the radius of the FOV. These trajectories are designed for circular FOVs. However, there are cases in which the required FOV is not circular but rather an ellipsoid. Methods: In this work, the authors show that in fan-beam CT, the use of a dynamically adjusting detector offset can reduce the required scan range when using a noncircular FOV. Furthermore, the authors present an analytic solution to determine the minimal required scan ranges for elliptic FOVs given a certain detector size and an algorithmic approach for arbitrary FOVs. Results: The authors show that the proposed method can result in a substantial reduction of the required scan range. Initial reconstructions of data sets acquired with our new minimal trajectory yielded image quality comparable to reconstructions of data acquired using a fixed detector offset and a full 360° rotation. Conclusions: Our results show a promising reduction of the necessary scan range especially for ellipsoidal objects that extend the FOV. In noncircular FOVs, there exists a set of solutions that allow a trade-off between detector size and scan range. PMID:25979070

  6. Bone dynamics in the upward direction after a maxillary sinus floor elevation procedure: serial segmentation using synchrotron radiation micro-computed tomography

    PubMed Central

    Seo, Seung-Jun; Bark, Chung Wung; Lim, Jae-Hong; Kim, Yong-Gun

    2015-01-01

    Objective Maxillary sinus floor augmentation has been shown to be the most predictable surgical technique for enhancing the bone volume in the posterior area of the maxilla. The purpose of this study was to analyze the serial slice image segmentation of newly formed bone and bone substitutes after sinus floor elevation using synchrotron radiation X-ray micro-computed tomography (SR-μCT). Materials and methods Bone biopsy specimens were collected after 6 months of sinus floor augmentation. From the six bone biopsy specimens, the cross-sectional images at every 8 μm along the apical direction from the inferior border using serial segmentation from three-dimensional reconstructed X-ray images were analyzed. The amount of new bone and bone substitutes were measured at each slicing image (300–430 images per specimen). Results The bone dynamics between the new bone and bone substitutes along the inferior–superior direction in humans after maxillary sinus floor elevation (MSFE) were analyzed using the whole sample region. Although these observations suggest that the specimens are structurally inhomogeneous, sinus floor elevation was confirmed to be a reliable surgical procedure for increasing the amount of bone. Conclusion SR-μCT is highly effective for obtaining high-resolution images. An analysis of biological specimens using SR-μCT is quite reliable and this technique will be an important tool in the wide field of tissue engineering. PMID:26347146

  7. Evaluation of the characteristics of hepatic focal nodular hyperplasia: correlation between dynamic contrast-enhanced multislice computed tomography and pathological findings

    PubMed Central

    Zhang, Hai-Tao; Gao, Xin-Yi; Xu, Qin-Sha; Chen, Yu-Tang; Song, Yu-Piao; Yao, Zhen-Wei

    2016-01-01

    Objective To evaluate the characteristics of enhancement of focal nodular hyperplasia (FNH) of the liver by analyzing the dynamic contrast-enhanced multislice computed tomography (MSCT) features and correlating them with pathological findings. Patients and methods Nine males and 16 females with pathologically confirmed FNH and complete preoperative contrast-enhanced MSCT data were recruited for this study. The imaging features of FNH on the pre- and postcontrast MSCT were analyzed by two experienced radiologists by consensus. Results Pathology showed central scars and abnormal blood vessels in 17 and 21 of 25 lesions, respectively, while MSCT with multiphase enhancement showed central scars in eight of the 17 lesions (47.1%) and abnormal arteries or draining veins in 13 of the 21 lesions (61.9%). Furthermore, abnormal draining veins in five lesions were found to be diagnostic, which is another important finding. Conclusion Multiphase scanning can provide the panorama of FNH lesions and reveal their enhancement patterns and pathological characteristics. Abnormal blood vessels within or around the lesion are demonstrated more often than central scar, and both should be observed for FNH diagnosis. PMID:27578988

  8. Computed Tomography Analysis of NASA BSTRA Balls

    SciTech Connect

    Perry, R L; Schneberk, D J; Thompson, R R

    2004-10-12

    Fifteen 1.25 inch BSTRA balls were scanned with the high energy computed tomography system at LLNL. This system has a resolution limit of approximately 210 microns. A threshold of 238 microns (two voxels) was used, and no anomalies at or greater than this were observed.

  9. Radiologist, computed tomography, and radiation therapy

    SciTech Connect

    Goitein, M.; Meyer, J.

    1982-06-01

    The use of computed tomography (CT) in planning radiation therapy is discussed. The three major issues that involve collaboration between the diagnostic radiologist and the radiation therapist are identified as selection of equipment, logistics, and conduct of individual CT studies. The importance of cooperation between the diagnostic and therapeutic radiologist is stressed.

  10. Cerebral computed tomography, 3rd Edition

    SciTech Connect

    Weisberg, L.; Nice, C.

    1988-01-01

    This book is an introduction to the utilization of computed tomography in evaluating patients with intracranial and orbital disorders. It features clinical correlations and provides an overview of general principles, performance, and normal anatomy of CT. It covers evaluation of specific neurologic signs and symptoms, including stroke, metastatic disease, increased intracranial pressure, head injury, pediatric conditions, and more.

  11. Computed tomography demonstration of cholecystogastric fistula.

    PubMed

    Chou, Chung Kuao

    2016-06-01

    Cholecystogastric fistula is a rare complication of chronic cholecystitis or long-standing cholelithiasis. It results from the gradual erosion of the approximated, chronically inflamed wall of the gall bladder and stomach with fistulous tract formation. The present case describes the direct visualization of a cholecystogastric fistula by computed tomography in a patient without prior biliary system complaints. PMID:27257453

  12. Computed tomography in the evaluation of trauma

    SciTech Connect

    Federle, M.P.; Brant-Zawadzki, M.

    1982-01-01

    This book is intended to be the current standard for computed tomography in the evaluation of trauma. It summarizes two years of experience at San Francisco General Hospital. The book is organized into seven chapters, covering head, maxillofacial, laryngeal, spinal, chest, abdominal, acetabular, and pelvic trauma. Extremity trauma is not discussed.

  13. Computed tomography in trauma: An atlas approach

    SciTech Connect

    Toombs, B.D.; Sandler, C.

    1986-01-01

    This book discussed computed tomography in trauma. The text is organized according to mechanism of injury and site of injury. In addition to CT, some correlation with other imaging modalities is included. Blunt trauma, penetrating trauma, complications and sequelae of trauma, and use of other modalities are covered.

  14. Diagnosis of juvenile angiofibroma by computed tomography.

    PubMed

    Weinstein, M A; Levine, H; Duchesneau, P M; Tucker, H M

    1978-03-01

    Computed tomography (CT) accurately localized juvenile angiofibromata in 3 patients. The expanded pterygopalatine fossa and canal were visualized by CT in all three cases. Because of the hemorrhagic tendency of these tumors, a noninvasive modality such as CT is especially valuable in planning therapy.

  15. [Computer tomography of retroperitoneal trauma (author's transl)].

    PubMed

    Fischedick, A R; Müller, R P; Kramps, H; Cramer, B

    1982-01-01

    Computer tomography changes after retroperitoneal trauma are described on the basis of 19 patients seen by the authors. It appears that this method is superior to conventional techniques, both as a screening method and for carrying out follow-ups. The indications for angiography are thereby reduced.

  16. Parallel Computing for the Computed-Tomography Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Lee, Seungwon

    2008-01-01

    This software computes the tomographic reconstruction of spatial-spectral data from raw detector images of the Computed-Tomography Imaging Spectrometer (CTIS), which enables transient-level, multi-spectral imaging by capturing spatial and spectral information in a single snapshot.

  17. Respirator triggering of electron-beam computed tomography (EBCT): differences in dynamic changes between augmented ventilation and controlled mechanical ventilation

    NASA Astrophysics Data System (ADS)

    Recheis, Wolfgang A.; Kleinsasser, Axel; Schuster, Antonius H.; Loeckinger, Alexander; Frede, Thomas; Springer, Peter; Hoermann, Christoph; zur Nedden, Dieter

    2000-04-01

    The purpose was to evaluate differences in dynamic changes of the lung aeration (air-tissue ratio) between augmented modes of ventilation (AMV) and controlled mechanical ventilation (CMV) in normal subjects. 4 volunteers, ventilated with the different respirator protocols via face mask, were scanned using the EBCT in the 50 ms mode. A software analyzed the respirator's digitized pressure and volume signals of two subsequent ventilation phases. Using these values it was possible to calculate the onset of inspiration or expiration of the next respiratory phase. The calculated starting point was then used to trigger the EBCT. The dynamic changes of air- tissue ratios were evaluated in three separate regions: a ventral, an intermediate and a dorsal area. AMV results in increase of air-tissue ratio in the dorsal lung area due to the active contraction of the diaphragm, whereas CMV results in a more pronounced increase in air-tissue ratio of the ventral lung area. This study gives further insight into the dynamic changes of the lung's biomechanics by comparing augmented ventilation and controlled mechanical ventilation in the healthy proband.

  18. Respirator triggering of electron beam computed tomography (EBCT): evaluation of dynamic changes during mechanical expiration in the traumatized patient

    NASA Astrophysics Data System (ADS)

    Recheis, Wolfgang A.; Kleinsasser, Axel; Hatschenberger, Robert; Knapp, Rudolf; zur Nedden, Dieter; Hoermann, Christoph

    1999-05-01

    The purpose of this project is to evaluate the dynamic changes during expiration at different levels of positive end- expiratory pressure (PEEP) in the ventilated patient. We wanted to discriminate between normal lung function and acute respiratory distress syndrome (ARDS). After approval by the local Ethic Committee we studied two ventilated patients: (1) with normal lung function; (2) ARDS). We used the 50 ms scan mode of the EBCT. The beam was positioned 1 cm above the diaphragm. The table position remained unchanged. An electronic trigger was developed, that utilizes the respirators synchronizing signal to start the EBCT at the onset of expiration. During controlled mechanical expiration at two levels of PEEP (0 and 15 cm H2O), pulmonary aeration was rated as: well-aerated (-900HU/-500HU), poorly- aerated (-500HU/-100HU) and non-aerated (-100HU/+100HU). Pathological and normal lung function showed different dynamic changes (FIG.4-12). The different PEEP levels resulted in a significant change of pulmonary aeration in the same patient. Although we studied only a very limited number of patients, respirator triggered EBCT may be accurate in discriminating pathological changes due to the abnormal lung function in the mechanically ventilated patient.

  19. Computed tomography of the spine

    SciTech Connect

    Haughton, V.M.; Williams, A.L.

    1982-01-01

    The book describes the computed tomographic (CT) techniques for imaging the different elements comprising the spinal column and canal. The use of intravenous and intrathecal contrast enhancement and of xenon enhancement is briefly mentioned. Reconstruction techniques and special problems regarding CT of the spine are presented. CT of the spinal cord, meninges and subarachnoid space, epidural space, intervertebral discs, facet joints, and vertebrae present normal anatomy, and several common pathologic conditions. (KRM)

  20. Longitudinal Evaluation of Sympathetic Nervous System and Perfusion in Normal and Spontaneously Hypertensive Rat Hearts with Dynamic Single-Photon Emission Computed Tomography.

    PubMed

    Zan, Yunlong; Boutchko, Rostyslav; Huang, Qiu; Li, Biao; Chen, Kewei; Gullberg, Grant T

    2015-01-01

    The objective of this work was to evaluate the sympathetic nervous system and structure remodeling during the progression of heart failure in a rodent model using dynamic cardiac single-photon emission computed tomography (SPECT). The spontaneously hypertensive rat (SHR) model was used to study changes in the nervous system innervation and perfusion in the left ventricular (LV) myocardium with the progression of left ventricular hypertrophy (LVH) to heart failure. Longitudinal dynamic SPECT studies were performed with seven SHR and seven Wistar-Kyoto (WKY) rats over 1.5 years using a dual-head SPECT scanner with pinhole collimators. Time-activity curves (TACs) of the 123I-MIBG and 201Tl distribution in the LV blood pool and myocardium were extracted from dynamic SPECT data and fitted to compartment models to determine the influx rate, washout rate, and distribution volume (DV) of 123I-MIBG and 201Tl in the LV myocardium. The standardized uptake values (SUVs) of 123I-MIBG and 201Tl in the LV myocardium were also calculated from the static reconstructed images. The influx and washout rates of 123I-MIBG did not show a significant difference between SHRs and WKY rats. The DVs of 123I-MIBG were greater in the SHRs than in the WKY rats (p = .0028). Specifically, the DV of 123I-MIBG became greater in the SHRs by 6 months of age (p = .0017) and was still significant at the age of 22 months. The SUV of 123I-MIBG in SHRs exhibited abnormal values compared to WKY rats from the age of 18 months. There was no difference in the influx rate and the washout rate of 201Tl between the SHRs and WKY rats. The SHRs exhibited greater DV of 201Tl than WKY rats after the age of 18 months (p = .034). The SUV of 201Tl in SHRs did not show any significant difference from WKY at all ages. The higher DV of 123I-MIBG in the LV myocardium reveals abnormal nervous system activity of the SHRs at an age of 6 months, whereas a greater DV of 201Tl in the LV myocardium can only be detected at an age

  1. Computed tomography of the medulla

    SciTech Connect

    Daniels, D.L.; Williams, A.L.; Haughton, V.M.

    1982-10-01

    The medulla was studied in cadavers and in 100 patients both with and without the intrathecal administration of contrast material. The computed tomographic (CT) anatomy was correlated with the appearance on anatomic dissections. The pyramids, olives, and inferior cerebellar peduncles produced characteristic contours on cross sections of the medulla. The hypoglossal nerve by its location and course in the medullary cistern could be distinguished from the glossopharyngeal, vagal, and spinal accessory nerves. For optimal evaluation of the medulla, intrathecal administration of metrizamide and 5- and/or 1.5-mm-thick axial and coronal sections are recommended.

  2. Introducing Seismic Tomography with Computational Modeling

    NASA Astrophysics Data System (ADS)

    Neves, R.; Neves, M. L.; Teodoro, V.

    2011-12-01

    Learning seismic tomography principles and techniques involves advanced physical and computational knowledge. In depth learning of such computational skills is a difficult cognitive process that requires a strong background in physics, mathematics and computer programming. The corresponding learning environments and pedagogic methodologies should then involve sets of computational modelling activities with computer software systems which allow students the possibility to improve their mathematical or programming knowledge and simultaneously focus on the learning of seismic wave propagation and inverse theory. To reduce the level of cognitive opacity associated with mathematical or programming knowledge, several computer modelling systems have already been developed (Neves & Teodoro, 2010). Among such systems, Modellus is particularly well suited to achieve this goal because it is a domain general environment for explorative and expressive modelling with the following main advantages: 1) an easy and intuitive creation of mathematical models using just standard mathematical notation; 2) the simultaneous exploration of images, tables, graphs and object animations; 3) the attribution of mathematical properties expressed in the models to animated objects; and finally 4) the computation and display of mathematical quantities obtained from the analysis of images and graphs. Here we describe virtual simulations and educational exercises which enable students an easy grasp of the fundamental of seismic tomography. The simulations make the lecture more interactive and allow students the possibility to overcome their lack of advanced mathematical or programming knowledge and focus on the learning of seismological concepts and processes taking advantage of basic scientific computation methods and tools.

  3. [Pneumothorax revealed by postoperative computed tomography].

    PubMed

    Ikeda, Shizuka; Katori, Kiyoshi; Fujimoto, Minoru; Nitahara, Keiichi; Higa, Kazuo

    2005-11-01

    We report a case of pneumothorax revealed by postoperative computed tomography. A 39-year-old obese woman (height 153 cm, weight 70 kg) with fractures of the radius, ulna, clavicle, and femur in a traffic accident, was scheduled for osteosynthesis. Anesthesia was induced with thiopental and maintained with 50% nitrous oxide in oxygen and sevoflurane. The Spo2 decreased from 99% to 94% during the surgery. Bilateral chest sounds were symmetrical. The Spo2 increased to 100% after discontinuation of nitrous oxide. Pneumothorax was not evident on a postoperative chest X-ray, but computed tomography of the chest demonstrated right-sided pneumothorax. An ECG electrode had overlapped the fractured rib on the preoperative chest X-ray.

  4. Computational fluid dynamics

    NASA Technical Reports Server (NTRS)

    1989-01-01

    An overview of computational fluid dynamics (CFD) activities at the Langley Research Center is given. The role of supercomputers in CFD research, algorithm development, multigrid approaches to computational fluid flows, aerodynamics computer programs, computational grid generation, turbulence research, and studies of rarefied gas flows are among the topics that are briefly surveyed.

  5. Computed tomography of the postoperative abdominal aorta

    SciTech Connect

    Hilton, S.; Megibow, A.J.; Naidich, D.P.; Bosniak, M.A.

    1982-11-01

    Computed tomography (CT) of the abdomen was performed on 46 patients who had undergone graft replacement of abdominal aortic aneurysms. Twelve post-operative complications were found in nine patients. They included hemorrhage, infection, anastomotic pseudoaneurysms, major vessel occlusion, postoperative pancreatitis, and others. The varied apperance of the normal postoperative graft is also presented. It is concluded that CT is a rapid, sensitive, and noninvasive method for detecting or excluding postoperative complications of abdominal aortic surgery.

  6. Computed tomography of hamstring muscle strains.

    PubMed

    Garrett, W E; Rich, F R; Nikolaou, P K; Vogler, J B

    1989-10-01

    Acute hamstring muscle strains occurring in ten college athletes were evaluated using computed tomography to identify the location and characteristics of these common injuries. Acute muscle strains appeared as areas of hypodensity within the muscle 1-2 d following injury. This suggests that inflammation and edema are the major component of injury, not bleeding as commonly assumed. Injuries were seen most commonly in the proximal and lateral portions of the hamstring muscle group, particularly in the biceps femoris.

  7. Computed tomography of ancient Egyptian mummies.

    PubMed

    Harwood-Nash, D C

    1979-12-01

    This first report of the application of computed tomography (CT) to the study of ancient mummies, the desiccated brain of a boy and the body of a young woman within her cartonnage, shows that CT is uniquely suitable for the study of such antiquities, a study that does not necessitate destruction of the mummy or its cartonnage. Exquisite images result that are of great paleoanatomical, paleopathological, and archeological significance.

  8. Computed tomography of the eye and orbit

    SciTech Connect

    Hammerschlag, S.B.; Hesselink, J.R.; Weber, A.L.

    1982-01-01

    This book is the product of the evolution of computed tomography (CT) into subspecialization and the need for one source of information for the busy radiologist. The authors have succeeded in providing a readable overview of orbital CT as well as a reference book. The book is divided into seven major catagories of pathology (Neurofibromatosis, Primary Orbital Neoplasms, Secondary and Metastic Tumors of the Orbit, Vascular Disorders, Inflammatory Disease, Occular Lesions, and Trauma) after separate discussions of anatomy and technique.

  9. Pharyngitis of infectious mononucleosis: computed tomography findings.

    PubMed

    Kutuya, Naoki; Kurosaki, Yoshihisa; Suzuki, Kazuhiro; Takata, Koremochi; Shiraihshi, Akihiko

    2008-05-01

    Two women presented with sore throat and fever. Their symptoms were not alleviated by antibiotics. Cervical computed tomography (CT) with contrast enhancement demonstrated enlargement of predominant posterior cervical lymph nodes and streaky heterogeneous tonsils with interspersed low attenuation. They were diagnosed as having infectious mononucleosis by their laboratory data. Thus, when radiologists encounter these CT findings of pharyngitis that is not alleviated by antibiotic therapy, infectious mononucleosis should be considered in the differential diagnosis.

  10. Metabolomics of Breast Cancer Using High-Resolution Magic Angle Spinning Magnetic Resonance Spectroscopy: Correlations with 18F-FDG Positron Emission Tomography-Computed Tomography, Dynamic Contrast-Enhanced and Diffusion-Weighted Imaging MRI

    PubMed Central

    Yoon, Haesung; Yoon, Dahye; Yun, Mijin; Choi, Ji Soo; Park, Vivian Youngjean; Kim, Eun-Kyung; Jeong, Joon; Koo, Ja Seung; Yoon, Jung Hyun; Moon, Hee Jung; Kim, Suhkmann; Kim, Min Jung

    2016-01-01

    Purpose Our goal in this study was to find correlations between breast cancer metabolites and conventional quantitative imaging parameters using high-resolution magic angle spinning (HR-MAS) magnetic resonance spectroscopy (MRS) and to find breast cancer subgroups that show high correlations between metabolites and imaging parameters. Materials and methods Between August 2010 and December 2013, we included 53 female patients (mean age 49.6 years; age range 32–75 years) with a total of 53 breast lesions assessed by the Breast Imaging Reporting and Data System. They were enrolled under the following criteria: breast lesions larger than 1 cm in diameter which 1) were suspicious for malignancy on mammography or ultrasound (US), 2) were pathologically confirmed to be breast cancer with US-guided core-needle biopsy (CNB) 3) underwent 3 Tesla MRI with dynamic contrast-enhanced (DCE) and diffusion-weighted imaging (DWI) and positron emission tomography-computed tomography (PET-CT), and 4) had an attainable immunohistochemistry profile from CNB. We acquired spectral data by HR-MAS MRS with CNB specimens and expressed the data as relative metabolite concentrations. We compared the metabolites with the signal enhancement ratio (SER), maximum standardized FDG uptake value (SUV max), apparent diffusion coefficient (ADC), and histopathologic prognostic factors for correlation. We calculated Spearman correlations and performed a partial least squares-discriminant analysis (PLS-DA) to further classify patient groups into subgroups to find correlation differences between HR-MAS spectroscopic values and conventional imaging parameters. Results In a multivariate analysis, the PLS-DA models built with HR-MAS MRS metabolic profiles showed visible discrimination between high and low SER, SUV, and ADC. In luminal subtype breast cancer, compared to all cases, high SER, ADV, and SUV were more closely clustered by visual assessment. Multiple metabolites were correlated with SER and SUV in

  11. Therapy response evaluation with positron emission tomography-computed tomography.

    PubMed

    Segall, George M

    2010-12-01

    Positron emission tomography-computed tomography with F-18-fluorodeoxyglucose is widely used for evaluation of therapy response in patients with solid tumors but has not been as readily adopted in clinical trials because of the variability of acquisition and processing protocols and the absence of universal response criteria. Criteria proposed for clinical trials are difficult to apply in clinical practice, and gestalt impression is probably accurate in individual patients, especially with respect to the presence of progressive disease and complete response. Semiquantitative methods of determining tissue glucose metabolism, such as standard uptake value, can be a useful descriptor for levels of tissue glucose metabolism and changes in response to therapy if technical quality control measures are carefully maintained. The terms partial response, complete response, and progressive disease are best used in clinical trials in which the terms have specific meanings and precise definitions. In clinical practice, it may be better to use descriptive terminology agreed upon by imaging physicians and clinicians in their own practice. PMID:21147376

  12. Computed tomography to quantify tooth abrasion

    NASA Astrophysics Data System (ADS)

    Kofmehl, Lukas; Schulz, Georg; Deyhle, Hans; Filippi, Andreas; Hotz, Gerhard; Berndt-Dagassan, Dorothea; Kramis, Simon; Beckmann, Felix; Müller, Bert

    2010-09-01

    Cone-beam computed tomography, also termed digital volume tomography, has become a standard technique in dentistry, allowing for fast 3D jaw imaging including denture at moderate spatial resolution. More detailed X-ray images of restricted volumes for post-mortem studies in dental anthropology are obtained by means of micro computed tomography. The present study evaluates the impact of the pipe smoking wear on teeth morphology comparing the abraded tooth with its contra-lateral counterpart. A set of 60 teeth, loose or anchored in the jaw, from 12 dentitions have been analyzed. After the two contra-lateral teeth were scanned, one dataset has been mirrored before the two datasets were registered using affine and rigid registration algorithms. Rigid registration provides three translational and three rotational parameters to maximize the overlap of two rigid bodies. For the affine registration, three scaling factors are incorporated. Within the present investigation, affine and rigid registrations yield comparable values. The restriction to the six parameters of the rigid registration is not a limitation. The differences in size and shape between the tooth and its contra-lateral counterpart generally exhibit only a few percent in the non-abraded volume, validating that the contralateral tooth is a reasonable approximation to quantify, for example, the volume loss as the result of long-term clay pipe smoking. Therefore, this approach allows quantifying the impact of the pipe abrasion on the internal tooth morphology including root canal, dentin, and enamel volumes.

  13. Positron Computed Tomography: Current State, Clinical Results and Future Trends

    DOE R&D Accomplishments Database

    Schelbert, H. R.; Phelps, M. E.; Kuhl, D. E.

    1980-09-01

    An overview is presented of positron computed tomography: its advantages over single photon emission tomography, its use in metabolic studies of the heart and chemical investigation of the brain, and future trends. (ACR)

  14. Monitoring the Effects of Anti-angiogenesis on the Radiation Sensitivity of Pancreatic Cancer Xenografts Using Dynamic Contrast-Enhanced Computed Tomography

    SciTech Connect

    Cao, Ning; Cao, Minsong; Chin-Sinex, Helen; Mendonca, Marc; Ko, Song-Chu; Stantz, Keith M.

    2014-02-01

    Purpose: To image the intratumor vascular physiological status of pancreatic tumors xenografts and their response to anti-angiogenic therapy using dynamic contrast-enhanced computed tomography (DCE-CT), and to identify parameters of vascular physiology associated with tumor x-ray sensitivity after anti-angiogenic therapy. Methods and Materials: Nude mice bearing human BxPC-3 pancreatic tumor xenografts were treated with 5 Gy of radiation therapy (RT), either a low dose (40 mg/kg) or a high dose (150 mg/kg) of DC101, the anti-VEGF receptor-2 anti-angiogenesis antibody, or with combination of low or high dose DC101 and 5 Gy RT (DC101-plus-RT). DCE-CT scans were longitudinally acquired over a 3-week period post-DC101 treatment. Parametric maps of tumor perfusion and fractional plasma volume (F{sub p}) were calculated and their averaged values and histogram distributions evaluated and compared to controls, from which a more homogeneous physiological window was observed 1-week post-DC101. Mice receiving a combination of DC101-plus-RT(5 Gy) were imaged baseline before receiving DC101 and 1 week after DC101 (before RT). Changes in perfusion and F{sub p} were compared with alternation in tumor growth delay for RT and DC101-plus-RT (5 Gy)-treated tumors. Results: Pretreatment with low or high doses of DC101 before RT significantly delayed tumor growth by an average 7.9 days compared to RT alone (P ≤ .01). The increase in tumor growth delay for the DC101-plus-RT-treated tumors was strongly associated with changes in tumor perfusion (ΔP>−15%) compared to RT treated tumors alone (P=.01). In addition, further analysis revealed a trend linking the tumor's increased growth delay to its tumor volume-to-DC101 dose ratio. Conclusions: DCE-CT is capable of monitoring changes in intratumor physiological parameter of tumor perfusion in response to anti-angiogenic therapy of a pancreatic human tumor xenograft that was associated with enhanced radiation response.

  15. Cone Beam Computed Tomography - Know its Secrets

    PubMed Central

    Kumar, Mohan; Shanavas, Muhammad; Sidappa, Ashwin; Kiran, Madhu

    2015-01-01

    Cone-beam computed tomography (CBCT) is an advanced imaging modality that has high clinical applications in the field of dentistry. CBCT proved to be a successful investigative modality that has been used for dental and maxillofacial imaging. Radiation exposure dose from CBCT is 10 times less than from conventional CT scans during maxillofacial exposure. Furthermore, CBCT is highly accurate and can provide a three-dimensional volumetric data in axial, sagittal and coronal planes. This article describes the basic technique, difference in CBCT from CT and main clinical applications of CBCT. PMID:25859112

  16. Emerging clinical applications of computed tomography

    PubMed Central

    Liguori, Carlo; Frauenfelder, Giulia; Massaroni, Carlo; Saccomandi, Paola; Giurazza, Francesco; Pitocco, Francesca; Marano, Riccardo; Schena, Emiliano

    2015-01-01

    X-ray computed tomography (CT) has recently been experiencing remarkable growth as a result of technological advances and new clinical applications. This paper reviews the essential physics of X-ray CT and its major components. Also reviewed are recent promising applications of CT, ie, CT-guided procedures, CT-based thermometry, photon-counting technology, hybrid PET-CT, use of ultrafast-high pitch scanners, and potential use of dual-energy CT for material differentiations. These promising solutions and a better knowledge of their potentialities should allow CT to be used in a safe and effective manner in several clinical applications. PMID:26089707

  17. Perforated Appendicitis: Assessment With Multidetector Computed Tomography.

    PubMed

    Iacobellis, Francesca; Iadevito, Isabella; Romano, Federica; Altiero, Michele; Bhattacharjee, Bikram; Scaglione, Mariano

    2016-02-01

    Appendicitis is one of the most common abdominal surgical emergencies. In some cases, the correct diagnosis may be challenging, owing to different conditions that can mimic this pathology. In this context, abdominal computed tomography (CT) is the imaging modality of choice, leading to an accurate diagnosis and to a reduction in unnecessary laparotomies. The diagnosis of perforated appendix is crucial, but the detection of the perforation signs by CT may not be so simple in the early process. The aim of this article is to review the multiple detector CT signs of perforated appendicitis.

  18. Computed tomography of infantile hepatic hemangioendothelioma

    SciTech Connect

    Lucaya, J.; Enriquez, G.; Amat, L.; Gonzalez-Rivero, M.A.

    1985-04-01

    Computed tomography (CT) was performed on five infants with hepatic hemangioendothelioma. Precontrast scans showed solitary or multiple, homogeneous, circumscribed areas with reduced attenuation values. Tiny tumoral calcifications were identified in two patients. Serial scans, after injection of a bolus of contrast material, showed early massive enhancement, which was either diffuse or peripheral. On delayed scans, multinocular tumors became isodense with surrounding liver, while all solitary ones showed varied degrees of centripetal enhancement and persistent central cleftlike unenhanced areas. The authors believe that these CT features are characteristic and obviate arteriographic confirmation.

  19. Advances in computed tomography imaging technology.

    PubMed

    Ginat, Daniel Thomas; Gupta, Rajiv

    2014-07-11

    Computed tomography (CT) is an essential tool in diagnostic imaging for evaluating many clinical conditions. In recent years, there have been several notable advances in CT technology that already have had or are expected to have a significant clinical impact, including extreme multidetector CT, iterative reconstruction algorithms, dual-energy CT, cone-beam CT, portable CT, and phase-contrast CT. These techniques and their clinical applications are reviewed and illustrated in this article. In addition, emerging technologies that address deficiencies in these modalities are discussed.

  20. Computed tomography and sialography: 2. Pathology.

    PubMed

    Carter, B L; Karmody, C S; Blickman, J R; Panders, A K

    1981-02-01

    Computed tomography (CT) has added a significant amount of diagnostic information to the imaging of the salivary glands. Two groups of patients were evaluated at two institutions to determine the impact of CT on the diagnosis of various diseases and to evaluate the contribution of CT versus conventional sialography, respectively. Patients were studied by each modality alone and in combination. Emphasis has been placed on the group that had CT combined with sialography, since benign and malignant tumors were found to be better evaluated by the two techniques together.

  1. COMPUTED TOMOGRAPHY OF TOOTH RESORPTION IN CATS.

    PubMed

    Lang, Linda G; Wilkinson, Thomas E; White, Tammy L; Farnsworth, Raelynn K; Potter, Kathleen A

    2016-09-01

    Tooth resorption is the most common dental disease in cats and can be a source of oral pain. The current clinical gold standard for diagnosis includes a combination of oral exam and dental radiography, however early lesions are not always detected. Computed tomography (CT) of the skull, including the dental arches, is a commonly performed diagnostic procedure, however the appearance of tooth resorption on CT and the diagnostic ability of CT to detect tooth resorption have not been evaluated. The purpose of this prospective, descriptive, diagnostic accuracy study was to characterize the CT appearance of tooth resorption in a sample of affected cats and to evaluate the sensitivity and specificity of CT for tooth resorption compared to the clinical gold standard of oral exam and intraoral dental radiography. Twenty-eight cat cadaver specimens were recruited for inclusion. Each specimen was evaluated using oral exam, intraoral dental radiography, and computed tomography (four different slice thicknesses). Each tooth was evaluated for the presence or absence of tooth resorption. Teeth with lesions and a subset of normal teeth were evaluated with histopathology. On CT, tooth resorption appeared as irregularly marginated hypoattenuating defects in the mineral attenuating tooth components, most commonly involving the root or cementoenamel junction. Sensitivity for CT detection of tooth resorption was fair to poor (42.2-57.7%) and specificity was good to excellent (92.8-96.3%). Findings from this study indicated that CT has high specificity but low sensitivity for detection of tooth resorption in cats.

  2. Comparison of computed tomography dose reporting software.

    PubMed

    Abdullah, A; Sun, Z; Pongnapang, N; Ng, K-H

    2012-08-01

    Computed tomography (CT) dose reporting software facilitates the estimation of doses to patients undergoing CT examinations. In this study, comparison of three software packages, i.e. CT-Expo (version 1.5, Medizinische Hochschule, Hannover, Germany), ImPACT CT Patients Dosimetry Calculator (version 0.99×, Imaging Performance Assessment on Computed Tomography, www.impactscan.org) and WinDose (version 2.1a, Wellhofer Dosimetry, Schwarzenbruck, Germany), has been made in terms of their calculation algorithm and the results of calculated doses. Estimations were performed for head, chest, abdominal and pelvic examinations based on the protocols recommended by European guidelines using single-slice CT (SSCT) (Siemens Somatom Plus 4, Erlangen, Germany) and multi-slice CT (MSCT) (Siemens Sensation 16, Erlangen, Germany) for software-based female and male phantoms. The results showed that there are some differences in final dose reporting provided by these software packages. There are deviations of effective doses produced by these software packages. Percentages of coefficient of variance range from 3.3 to 23.4 % in SSCT and from 10.6 to 43.8 % in MSCT. It is important that researchers state the name of the software that is used to estimate the various CT dose quantities. Users must also understand the equivalent terminologies between the information obtained from the CT console and the software packages in order to use the software correctly.

  3. Computed Tomography Technology: Development and Applications for Defence

    SciTech Connect

    Baheti, G. L.; Saxena, Nisheet; Tripathi, D. K.; Songara, K. C.; Meghwal, L. R.; Meena, V. L.

    2008-09-26

    Computed Tomography(CT) has revolutionized the field of Non-Destructive Testing and Evaluation (NDT and E). Tomography for industrial applications warrants design and development of customized solutions catering to specific visualization requirements. Present paper highlights Tomography Technology Solutions implemented at Defence Laboratory, Jodhpur (DLJ). Details on the technological developments carried out and their utilization for various Defence applications has been covered.

  4. Computed Tomography Technology: Development and Applications for Defence

    NASA Astrophysics Data System (ADS)

    Baheti, G. L.; Saxena, Nisheet; Tripathi, D. K.; Songara, K. C.; Meghwal, L. R.; Meena, V. L.

    2008-09-01

    Computed Tomography(CT) has revolutionized the field of Non-Destructive Testing and Evaluation (NDT&E). Tomography for industrial applications warrants design and development of customized solutions catering to specific visualization requirements. Present paper highlights Tomography Technology Solutions implemented at Defence Laboratory, Jodhpur (DLJ). Details on the technological developments carried out and their utilization for various Defence applications has been covered.

  5. Towards Dynamic Contrast Specific Ultrasound Tomography

    PubMed Central

    Demi, Libertario; Van Sloun, Ruud J. G.; Wijkstra, Hessel; Mischi, Massimo

    2016-01-01

    We report on the first study demonstrating the ability of a recently-developed, contrast-enhanced, ultrasound imaging method, referred to as cumulative phase delay imaging (CPDI), to image and quantify ultrasound contrast agent (UCA) kinetics. Unlike standard ultrasound tomography, which exploits changes in speed of sound and attenuation, CPDI is based on a marker specific to UCAs, thus enabling dynamic contrast-specific ultrasound tomography (DCS-UST). For breast imaging, DCS-UST will lead to a more practical, faster, and less operator-dependent imaging procedure compared to standard echo-contrast, while preserving accurate imaging of contrast kinetics. Moreover, a linear relation between CPD values and ultrasound second-harmonic intensity was measured (coefficient of determination = 0.87). DCS-UST can find clinical applications as a diagnostic method for breast cancer localization, adding important features to multi-parametric ultrasound tomography of the breast. PMID:27703251

  6. Towards Dynamic Contrast Specific Ultrasound Tomography

    NASA Astrophysics Data System (ADS)

    Demi, Libertario; van Sloun, Ruud J. G.; Wijkstra, Hessel; Mischi, Massimo

    2016-10-01

    We report on the first study demonstrating the ability of a recently-developed, contrast-enhanced, ultrasound imaging method, referred to as cumulative phase delay imaging (CPDI), to image and quantify ultrasound contrast agent (UCA) kinetics. Unlike standard ultrasound tomography, which exploits changes in speed of sound and attenuation, CPDI is based on a marker specific to UCAs, thus enabling dynamic contrast-specific ultrasound tomography (DCS-UST). For breast imaging, DCS-UST will lead to a more practical, faster, and less operator-dependent imaging procedure compared to standard echo-contrast, while preserving accurate imaging of contrast kinetics. Moreover, a linear relation between CPD values and ultrasound second-harmonic intensity was measured (coefficient of determination = 0.87). DCS-UST can find clinical applications as a diagnostic method for breast cancer localization, adding important features to multi-parametric ultrasound tomography of the breast.

  7. The effect of respiratory motion variability and tumor size on the accuracy of average intensity projection from four-dimensional computed tomography: an investigation based on dynamic MRI.

    PubMed

    Cai, Jing; Read, Paul W; Sheng, Ke

    2008-11-01

    Composite images such as average intensity projection (AIP) and maximum intensity projection (MIP) derived from four-dimensional computed tomography (4D-CT) images are commonly used in radiation therapy for treating lung and abdominal tumors. It has been reported that the quality of 4D-CT images is influenced by the patient respiratory variability, which can be assessed by the standard deviation of the peak and valley of the respiratory trajectory. Subsequently, the resultant MIP underestimates the actual tumor motion extent. As a more general application, AIP comprises not only the tumor motion extent but also the probability that the tumor is present. AIP generated from 4D-CT can also be affected by the respiratory variability. To quantitate the accuracy of AIP and develop clinically relevant parameters for determining suitability of the 4D-CT study for AIP-based treatment planning, real time sagittal dynamic magnetic resonance imaging (dMRI) was used as the basis for generating simulated 4D-CT. Five-minute MRI scans were performed on seven healthy volunteers and eight lung tumor patients. In addition, images of circular phantoms with diameter 1, 3, or 5 cm were generated by software to simulate lung tumors. Motion patterns determined by dMRI images were reproduced by the software generated phantoms. Resorted dMRI using a 4D-CT acquisition method (RedCAM) based on phantom or patient images was reconstructed by simulating the imaging rebinning processes. AIP images and the corresponding color intensity projection (CIP) images were reconstructed from RedCAM and the full set of dMRI for comparison. AIP similarity indicated by the Dice index between RedCAM and dMRI was calculated and correlated with respiratory variability (v) and tumor size (s). The similarity of percentile intrafractional motion target area (IMTA), defined by the area that the tumor presented for a given percentage of time, and MIP-to-percentile IMTA similarity as a function of percentile were also

  8. Single-photon emission computed tomography (SPECT): Applications and potential

    SciTech Connect

    Holman, B.L.; Tumeh, S.S. )

    1990-01-26

    Single-photon emission computed tomography has received increasing attention as radiopharmaceuticals that reflect perfusion, metabolism, and receptor and cellular function have become widely available. Perfusion single-photon emission computed tomography of the brain provides functional information useful for the diagnosis and management of stroke, dementia, and epilepsy. Single-photon emission computed tomography has been applied to myocardial, skeletal, hepatic, and tumor scintigraphy, resulting in increased diagnostic accuracy over planar imaging because background activity and overlapping tissues interfere far less with activity from the target structure when tomographic techniques are used. Single-photon emission computed tomography is substantially less expensive and far more accessible than positron emission tomography and will become an increasingly attractive alternative for transferring the positron emission tomography technology to routine clinical use.

  9. Ultra-high resolution computed tomography imaging

    DOEpatents

    Paulus, Michael J.; Sari-Sarraf, Hamed; Tobin, Jr., Kenneth William; Gleason, Shaun S.; Thomas, Jr., Clarence E.

    2002-01-01

    A method for ultra-high resolution computed tomography imaging, comprising the steps of: focusing a high energy particle beam, for example x-rays or gamma-rays, onto a target object; acquiring a 2-dimensional projection data set representative of the target object; generating a corrected projection data set by applying a deconvolution algorithm, having an experimentally determined a transfer function, to the 2-dimensional data set; storing the corrected projection data set; incrementally rotating the target object through an angle of approximately 180.degree., and after each the incremental rotation, repeating the radiating, acquiring, generating and storing steps; and, after the rotating step, applying a cone-beam algorithm, for example a modified tomographic reconstruction algorithm, to the corrected projection data sets to generate a 3-dimensional image. The size of the spot focus of the beam is reduced to not greater than approximately 1 micron, and even to not greater than approximately 0.5 microns.

  10. Quality assessment of clinical computed tomography

    NASA Astrophysics Data System (ADS)

    Berndt, Dorothea; Luckow, Marlen; Lambrecht, J. Thomas; Beckmann, Felix; Müller, Bert

    2008-08-01

    Three-dimensional images are vital for the diagnosis in dentistry and cranio-maxillofacial surgery. Artifacts caused by highly absorbing components such as metallic implants, however, limit the value of the tomograms. The dominant artifacts observed are blowout and streaks. Investigating the artifacts generated by metallic implants in a pig jaw, the data acquisition for the patients in dentistry should be optimized in a quantitative manner. A freshly explanted pig jaw including related soft-tissues served as a model system. Images were recorded varying the accelerating voltage and the beam current. The comparison with multi-slice and micro computed tomography (CT) helps to validate the approach with the dental CT system (3D-Accuitomo, Morita, Japan). The data are rigidly registered to comparatively quantify their quality. The micro CT data provide a reasonable standard for quantitative data assessment of clinical CT.

  11. System Matrix Analysis for Computed Tomography Imaging

    PubMed Central

    Flores, Liubov; Vidal, Vicent; Verdú, Gumersindo

    2015-01-01

    In practical applications of computed tomography imaging (CT), it is often the case that the set of projection data is incomplete owing to the physical conditions of the data acquisition process. On the other hand, the high radiation dose imposed on patients is also undesired. These issues demand that high quality CT images can be reconstructed from limited projection data. For this reason, iterative methods of image reconstruction have become a topic of increased research interest. Several algorithms have been proposed for few-view CT. We consider that the accurate solution of the reconstruction problem also depends on the system matrix that simulates the scanning process. In this work, we analyze the application of the Siddon method to generate elements of the matrix and we present results based on real projection data. PMID:26575482

  12. Clinically applicable gated cardiac computed tomography

    SciTech Connect

    Cipriano, P.R.; Nassi, M.; Brody, W.R.

    1983-03-01

    Several attempts have been made to improve cardiac images obtained with x-ray transmission computed tomography (CT) by stopping cardiac motion through electrocardiographic gating. These methods reconstruct images that correspond to time intervals of the cardiac cycle identified by electrocardiography using either a pulsed x-ray beam at a selected time in the cardiac cycle or selected measurements in retrospect from regularly pulsed measurements made over several cardiac cycles. Missing CT angles of view (line integrals) have been a major problem contributing to degradation of such gated cardiac CT images. A new method for CT reconstruction from an incomplete set of projection data is presented that can be used clinically with a standard fan-beam reconstruction algorithm to improve gated cardiac CT images.

  13. Analysis of Ventricular Function by Computed Tomography

    PubMed Central

    Rizvi, Asim; Deaño, Roderick C.; Bachman, Daniel P.; Xiong, Guanglei; Min, James K.; Truong, Quynh A.

    2014-01-01

    The assessment of ventricular function, cardiac chamber dimensions and ventricular mass is fundamental for clinical diagnosis, risk assessment, therapeutic decisions, and prognosis in patients with cardiac disease. Although cardiac computed tomography (CT) is a noninvasive imaging technique often used for the assessment of coronary artery disease, it can also be utilized to obtain important data about left and right ventricular function and morphology. In this review, we will discuss the clinical indications for the use of cardiac CT for ventricular analysis, review the evidence on the assessment of ventricular function compared to existing imaging modalities such cardiac MRI and echocardiography, provide a typical cardiac CT protocol for image acquisition and post-processing for ventricular analysis, and provide step-by-step instructions to acquire multiplanar cardiac views for ventricular assessment from the standard axial, coronal, and sagittal planes. Furthermore, both qualitative and quantitative assessments of ventricular function as well as sample reporting are detailed. PMID:25576407

  14. Imaging of the heart with computed tomography.

    PubMed

    Flohr, Thomas G; Ohnesorge, Bernd M

    2008-03-01

    Imaging of the heart with computed tomography (CT) was already introduced in the 1980Is and has meanwhile entered clinical routine as a consequence of the rapid evolution of CT technology during the last decade. In this review article, we give an overview on the technology and clinical performance of different CT-scanner generations used for cardiac imaging, such as Electron Beam CT (EBCT), single-slice CT und multi-detector row CT (MDCT) with 4, 16 and 64 simultaneously acquired slices. We identify the limitations of current CT-scanners, indicate potential of improvement and discuss alternative system concepts such as CT with area detectors and dual source CT (DSCT). PMID:18324372

  15. Computed tomography of radioactive objects and materials

    NASA Astrophysics Data System (ADS)

    Sawicka, B. D.; Murphy, R. V.; Tosello, G.; Reynolds, P. W.; Romaniszyn, T.

    1990-12-01

    Computed tomography (CT) has been performed on a number of radioactive objects and materials. Several unique technical problems are associated with CT of radioactive specimens. These include general safety considerations, techniques to reduce background-radiation effects on CT images and selection criteria for the CT source to permit object penetration and to reveal accurate values of material density. In the present paper, three groups of experiments will be described, for objects with low, medium and high levels of radioactivity. CT studies on radioactive specimens will be presented. They include the following: (1) examination of individual ceramic reactor-fuel (uranium dioxide) pellets, (2) examination of fuel samples from the Three Mile Island reactor, (3) examination of a CANDU (CANada Deuterium Uraniun: registered trademark) nuclear-fuel bundle which underwent a simulated loss-of-coolant accident resulting in high-temperature damage and (4) examination of a PWR nuclear-reactor fuel assembly.

  16. Computed tomography of the abnormal thymus

    SciTech Connect

    Baron, R.L.; Lee, J.K.T.; Sagel, S.S.; Levitt, R.G.

    1982-01-01

    Computed tomography (CT) should be the imaging method of choice following plain chest radiographs when a suspected thymic abnormality requires further evaluation. Based upon a six-year experience, including the evaluation of 25 patients with thymic pathology, CT was found useful in suggesting or excluding a diagnosis of thymoma and in distinguishing thymic hyperplasis from thymoma in patients with myasthenia gravis. The thickness of the thymic lobes determined by CT was found to be a more accurate indicator of infiltrative disease (thymic hyperplasia and lymphoma) than the width. CT was helpful in differentiating benign thymic cysts from solid tumors, and in defining the extent of a thymic neoplasms. On occasion, CT may suggest the specific histologic nature of a thymic lesion.

  17. System Matrix Analysis for Computed Tomography Imaging.

    PubMed

    Flores, Liubov; Vidal, Vicent; Verdú, Gumersindo

    2015-01-01

    In practical applications of computed tomography imaging (CT), it is often the case that the set of projection data is incomplete owing to the physical conditions of the data acquisition process. On the other hand, the high radiation dose imposed on patients is also undesired. These issues demand that high quality CT images can be reconstructed from limited projection data. For this reason, iterative methods of image reconstruction have become a topic of increased research interest. Several algorithms have been proposed for few-view CT. We consider that the accurate solution of the reconstruction problem also depends on the system matrix that simulates the scanning process. In this work, we analyze the application of the Siddon method to generate elements of the matrix and we present results based on real projection data. PMID:26575482

  18. Human echinococcosis: diagnostic value of computed tomography.

    PubMed

    Grabbe, E; Kern, P; Heller, M

    1981-03-01

    The diagnostic value of computed tomography was assessed in 44 patients with alveolar or cystic echinococcosis. The CT-examination was concentrated mainly on the liver, which was involved in all patients. It was extended to other organs, i.e. to lung, intra- or retroperitoneal space, bone and brain if necessary. The CT image of the liver in cystic echinococcosis was often characteristic. It showed sharply outlined masses with attenuation values similar to water. Internal structures were caused by daughter cysts. Furthermore, typical marginal calcium deposits indicated regressive changes in the host membrane. In all cases with alveolar echinococcosis in indistinct solid mass was found, often with central necrotic colliquation and plaque-like calcifications within the tumor.

  19. Computed tomography of osteosarcoma after intraarterial chemotherapy

    SciTech Connect

    Shirkhoda, A.; Jaffe, N.; Wallace, S.; Ayala, A.; Lindell, M.M.; Zornoza, J.

    1985-01-01

    The response to intraarterial cis-diamminedichloroplatinum II (CDP) chemotherapy was evaluated by computed tomography (CT) in 33 patients with pathologically proved osteosarcoma of the long or flat bones. Twenty-one of the 33 patients had a CT scan before chemotherapy was started. In the other 12 patients, a CT scan was obtained after at least two courses of treatment, and additional studies were performed during the course of therapy. In those patients responding to treatment, the posttherapy scan revealed a remarkable decrease or complete disappearance of the associated soft-tissue mass and clear reestablishment of the fat planes between the muscle bundles that had been obscured. There was sharp definition of the peripheral margins of the calcified healing neoplasm, and the calcification in the healing tumor could be differentiated easily from that of the original bone neoplasm. CT was more accurate than conventional studies in detecting healing process and diagnosis of remission.

  20. Computed tomography on small explosive parts

    SciTech Connect

    Ryon, R.W.

    1994-05-01

    We have investigated three small explosive parts for the Pantex Plant in Amarillo, Texas using computed tomography (CT). A medium resolution, fan beam system was used to test imaging capabilities for small holes drilled into one of the parts, and to identify any inhomogeneities, cracks, voids, and inclusions if present in the other two parts. This system provides volumetric imaging. Its information is qualitative in that is allows us to see interior features but it cannot provide quantitative attenuation data. A second part of the investigation was to perform effective atomic number computed tomography on the parts using energy dispersive spectroscopy methods. We wanted to experimentally identify the {open_quotes}average{close_quotes} chemical composition of the materials in the explosive and its shell and to detect any possible inhomogeneities in composition. A single beam, nuclear spectroscopy based system was used for this work. The radiation source was a silver anode x-ray tube. By measuring x-ray attenuation at specific energies (characteristic lines and narrow bands of continuum) we are able to quantitatively determine linear attenuation coefficients. By using ratios of such measurements, density cancels out and we effectively have ratios of mass attenuation coefficients. Through a look-up scheme of mass attenuation coefficients for different elements, we can determine the weighted average chemical composition, as averaged by x-ray attenuation. We call this averaged composition the effective atomic number ({open_quotes}Z{sub eff}{close_quotes}). We thereby obtain cross sectional images of a parameter related to the averaged chemistry of the object. Such images and the underlying data can reveal, for instance, segregation of explosive and binder.

  1. Depiction of ventriculoperitoneal shunt obstruction with single-photon emission computed tomography/computed tomography

    PubMed Central

    Aksoy, Sabire Yılmaz; Vatankulu, Betül; Uslu, Lebriz; Halac, Metin

    2016-01-01

    An 83-year-old male patient with ventriculoperitoneal shunt underwent radionuclide shunt study using single-photon emission computed tomography/computed tomography (SPECT/CT) to evaluate the shunt patency. The planar images showed activity at the cranial region and spinal canal but no significant activity at the peritoneal cavity. However, SPECT/CT images clearly demonstrated accumulation of activity at the superior part of bifurcation level with no activity at the distal end of shunt as well as no spilling of radiotracer into the peritoneal cavity indicating shunt obstruction. SPECT/CT makes the interpretation of radionuclide shunt study more accurate and easier as compared with traditional planar images. PMID:27385906

  2. 21 CFR 892.1200 - Emission computed tomography system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... system. (a) Identification. An emission computed tomography system is a device intended to detect...

  3. 21 CFR 892.1200 - Emission computed tomography system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... system. (a) Identification. An emission computed tomography system is a device intended to detect...

  4. 21 CFR 892.1200 - Emission computed tomography system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... system. (a) Identification. An emission computed tomography system is a device intended to detect...

  5. Giant intracranial aneurysms: rapid sequential computed tomography

    SciTech Connect

    Pinto, R.S.; Cohen, W.A.; Kricheff, I.I.; Redington, R.W.; Berninger, W.H.

    1982-11-01

    Giant intracranial aneurysms often present as mass lesions rather than with subarachnoid hemorrhage. Routine computed tomographic (CT) scans with contrast material will generally detect them, but erroneous diagnosis of basal meningioma is possible. Rapid sequential scanning (dynamic CT) after bolus injection of 40 ml of Renografin-76 can conclusively demonstrate an intracranial aneurysm, differentiating it from other lesions by transit-time analysis of the passage of contrast medium. In five patients, the dynamics of contrast bolus transit in aneurysms were consistently different from the dynamics in pituitary tumors, craniopharyngiomas, and meningiomas, thereby allowing a specific diagnosis. Dynamic CT was also useful after treatment of the aneurysms by carotid artery ligation and may be used as an alternative to angiographic evaluation in determining luminal patency or thrombosis.

  6. Terahertz Computed Tomography of NASA Thermal Protection System Materials

    NASA Technical Reports Server (NTRS)

    Roth, D. J.; Reyes-Rodriguez, S.; Zimdars, D. A.; Rauser, R. W.; Ussery, W. W.

    2011-01-01

    A terahertz axial computed tomography system has been developed that uses time domain measurements in order to form cross-sectional image slices and three-dimensional volume renderings of terahertz-transparent materials. The system can inspect samples as large as 0.0283 cubic meters (1 cubic foot) with no safety concerns as for x-ray computed tomography. In this study, the system is evaluated for its ability to detect and characterize flat bottom holes, drilled holes, and embedded voids in foam materials utilized as thermal protection on the external fuel tanks for the Space Shuttle. X-ray micro-computed tomography was also performed on the samples to compare against the terahertz computed tomography results and better define embedded voids. Limits of detectability based on depth and size for the samples used in this study are loosely defined. Image sharpness and morphology characterization ability for terahertz computed tomography are qualitatively described.

  7. Texture classification of lung computed tomography images

    NASA Astrophysics Data System (ADS)

    Pheng, Hang See; Shamsuddin, Siti M.

    2013-03-01

    Current development of algorithms in computer-aided diagnosis (CAD) scheme is growing rapidly to assist the radiologist in medical image interpretation. Texture analysis of computed tomography (CT) scans is one of important preliminary stage in the computerized detection system and classification for lung cancer. Among different types of images features analysis, Haralick texture with variety of statistical measures has been used widely in image texture description. The extraction of texture feature values is essential to be used by a CAD especially in classification of the normal and abnormal tissue on the cross sectional CT images. This paper aims to compare experimental results using texture extraction and different machine leaning methods in the classification normal and abnormal tissues through lung CT images. The machine learning methods involve in this assessment are Artificial Immune Recognition System (AIRS), Naive Bayes, Decision Tree (J48) and Backpropagation Neural Network. AIRS is found to provide high accuracy (99.2%) and sensitivity (98.0%) in the assessment. For experiments and testing purpose, publicly available datasets in the Reference Image Database to Evaluate Therapy Response (RIDER) are used as study cases.

  8. Computed Tomography in Diagnosis of Admantinoma

    PubMed Central

    Misra, Akansha; Misra, Deepankar; Rai, Shalu; Panjwani, Sapna; Ranjan, Vikash; Prabhat, Mukul; Bhalla, Kanika; Bhatnagar, Puneet

    2015-01-01

    Context: Admantinoma is second most common benign odontogenic tumor which clinically appears as an aggressive odontogenic tumor, often asymptomatic and slow growing, associated with symptoms such as swelling, dental malocclusion, pain, and paresthesia of the affected area. The radiographic appearance may vary from unilocular to multilocular radiolucencies, imparting a characteristic honey comb, soap bubble appearance or may resemble a caricature of spider. Case Report: This report highlights the importance of conventional and advanced imaging in the diagnosis of large and invasive lesions. Patient reported with complaint of swelling in jaw, which progressively increased; and was found to be bony hard, both intra- and extraorally. Radiographs revealed large multilocular radiolucency on left body and ramus of mandible with soap bubble pattern and knife edged root resorption. Computed tomographic examination evaluated the extent of the lesion, internal structure, and relation to adjacent structures; further a reconstructed image was obtained to evaluate extent of destruction in three dimensions. Conclusion: Computed tomography has an important role in the diagnosis and treatment planning is imperative as it is superior in revealing the cortical destruction and extension into the neighboring soft tissues than conventional radiography. PMID:26110136

  9. Computational fluid dynamic control

    NASA Technical Reports Server (NTRS)

    Hartley, Tom T.; Deabreu-Garcia, Alex

    1989-01-01

    A general technique is presented for modeling fluid, or gas, dynamic systems specifically for the development of control systems. The numerical methods which are generally used in computational fluid dynamics are borrowed to create either continuous-time or discrete-time models of the particular fluid system. The resulting equations can be either left in a nonlinear form, or easily linearized about an operating point. As there are typically very many states in these systems, the usual linear model reduction methods can be used on them to allow a low-order controller to be designed. A simple example is given which typifies many internal flow control problems. The resulting control is termed computational fluid dynamic control.

  10. Malignant uveal melanoma and similar lesions studied by computed tomography

    SciTech Connect

    Mafee, M.F.; Peyman, G.A.; McKusick, M.A.

    1985-08-01

    Forty-four patients with intraocular disease were studied by computed tomography (CT); in 19 cases malignant uveal melanoma was considered the likely diagnosis. CT proved to be accurate in determining the location and size of uveal melanomas, demonstrating scleral invasion, and differentiating melanoma from choroidal detachment or angioma, toxocariasis, and senile macular degeneration. On CT, uveal melanomas appeared as hyperdense lesions with slight to moderate contrast enhancement. Tumors thinner than 2 mm could not be seen. Using dynamic CT, the authors noted moderate peak amplitude, normal or delayed tissue transit time, and persistently elevated washout phase (downslope), indicating increased permeability as the result of an impaired tumor blood barrier. Histological types of uveal melanoma could not be differentiated on the basis of circulatory patterns. Dynamic CT may be useful in distinguishing uveal melanoma from choroidal hemangioma or hematoma.

  11. 4-D reconstruction for dynamic fluorescence diffuse optical tomography.

    PubMed

    Liu, Xin; Zhang, Bin; Luo, Jianwen; Bai, Jing

    2012-11-01

    Dynamic fluorescence diffuse optical tomography (FDOT) is important for the research of drug delivery, medical diagnosis and treatment. Conventionally, dynamic tomographic images are reconstructed frame by frame, independently. This approach fails to account for the temporal correlations in measurement data. Ideally, the entire image sequence should be considered as a whole and a four-dimensional (4-D) reconstruction should be performed. However, the fully 4-D reconstruction is computationally intensive. In this paper, we propose a new 4-D reconstruction approach for dynamic FDOT, which is achieved by applying a temporal Karhunen-Loève (KL) transformation to the imaging equation. By taking advantage of the decorrelation and compression properties of the KL transformation, the complex 4-D optical reconstruction problem is greatly simplified. To evaluate the performance of the method, simulation, phantom, and in vivo experiments (N=7) are performed on a hybrid FDOT/x-ray computed tomography imaging system. The experimental results indicate that the reconstruction images obtained by the KL method provide good reconstruction quality. Additionally, by discarding high-order KL components, the computation time involved with fully 4-D reconstruction can be greatly reduced in contrast to the conventional frame-by-frame reconstruction.

  12. Dedicated breast computed tomography: Basic aspects.

    PubMed

    Sarno, Antonio; Mettivier, Giovanni; Russo, Paolo

    2015-06-01

    X-ray mammography of the compressed breast is well recognized as the "gold standard" for early detection of breast cancer, but its performance is not ideal. One limitation of screening mammography is tissue superposition, particularly for dense breasts. Since 2001, several research groups in the USA and in the European Union have developed computed tomography (CT) systems with digital detector technology dedicated to x-ray imaging of the uncompressed breast (breast CT or BCT) for breast cancer screening and diagnosis. This CT technology--tracing back to initial studies in the 1970s--allows some of the limitations of mammography to be overcome, keeping the levels of radiation dose to the radiosensitive breast glandular tissue similar to that of two-view mammography for the same breast size and composition. This paper presents an evaluation of the research efforts carried out in the invention, development, and improvement of BCT with dedicated scanners with state-of-the-art technology, including initial steps toward commercialization, after more than a decade of R&D in the laboratory and/or in the clinic. The intended focus here is on the technological/engineering aspects of BCT and on outlining advantages and limitations as reported in the related literature. Prospects for future research in this field are discussed. PMID:26127031

  13. Modelling the penumbra in Computed Tomography1

    PubMed Central

    Kueh, Audrey; Warnett, Jason M.; Gibbons, Gregory J.; Brettschneider, Julia; Nichols, Thomas E.; Williams, Mark A.; Kendall, Wilfrid S.

    2016-01-01

    BACKGROUND: In computed tomography (CT), the spot geometry is one of the main sources of error in CT images. Since X-rays do not arise from a point source, artefacts are produced. In particular there is a penumbra effect, leading to poorly defined edges within a reconstructed volume. Penumbra models can be simulated given a fixed spot geometry and the known experimental setup. OBJECTIVE: This paper proposes to use a penumbra model, derived from Beer’s law, both to confirm spot geometry from penumbra data, and to quantify blurring in the image. METHODS: Two models for the spot geometry are considered; one consists of a single Gaussian spot, the other is a mixture model consisting of a Gaussian spot together with a larger uniform spot. RESULTS: The model consisting of a single Gaussian spot has a poor fit at the boundary. The mixture model (which adds a larger uniform spot) exhibits a much improved fit. The parameters corresponding to the uniform spot are similar across all powers, and further experiments suggest that the uniform spot produces only soft X-rays of relatively low-energy. CONCLUSIONS: Thus, the precision of radiographs can be estimated from the penumbra effect in the image. The use of a thin copper filter reduces the size of the effective penumbra. PMID:27232198

  14. A Detector for Proton Computed Tomography

    SciTech Connect

    Blazey, G.; et al.,

    2013-12-06

    Radiation therapy is a widely recognized treatment for cancer. Energetic protons have distinct features that set them apart from photons and make them desirable for cancer therapy as well as medical imaging. The clinical interest in heavy ion therapy is due to the fact that ions deposit almost all of their energy in a sharp peak – the Bragg peak- at the very end of their path. Proton beams can be used to precisely localize a tumor and deliver an exact dose to the tumor with small doses to the surrounding tissue. Proton computed tomography (pCT) provides direct information on the location on the target tumor, and avoids position uncertainty caused by treatment planning based on imaging with X-ray CT. The pCT project goal is to measure and reconstruct the proton relative stopping power distribution directly in situ. To ensure the full advantage of cancer treatment with 200 MeV proton beams, pCT must be realized.

  15. Cosine fitting radiography and computed tomography

    NASA Astrophysics Data System (ADS)

    Li, Pan-Yun; Zhang, Kai; Huang, Wan-Xia; Yuan, Qing-Xi; Wang, Yan; Ju, Zai-Qiang; Wu, Zi-Yu; Zhu, Pei-Ping

    2015-06-01

    A new method in diffraction-enhanced imaging computed tomography (DEI-CT) that follows the idea developed by Chapman et al. [Chapman D, Thomlinson W, Johnston R E, Washburn D, Pisano E, Gmur N, Zhong Z, Menk R, Arfelli F and Sayers D 1997 Phys. Med. Biol. 42 2015] in 1997 is proposed in this paper. Merged with a “reverse projections” algorithm, only two sets of projection datasets at two defined orientations of the analyzer crystal are needed to reconstruct the linear absorption coefficient, the decrement of the real part of the refractive index and the linear scattering coefficient of the sample. Not only does this method reduce the delivered dose to the sample without degrading the image quality, but, compared with the existing DEI-CT approaches, it simplifies data-acquisition procedures. Experimental results confirm the reliability of this new method for DEI-CT applications. Project supported by the National Basic Research Program of China (Grant No. 2012CB825800), the National Natural Science Foundation of China (Grant Nos. 11205189, 11375225, and U1332109), the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant Nos. KJCX2-YW-N42, Y4545320Y2, and 542014IHEPZZBS50659).

  16. Computed tomography characterisation of additive manufacturing materials.

    PubMed

    Bibb, Richard; Thompson, Darren; Winder, John

    2011-06-01

    Additive manufacturing, covering processes frequently referred to as rapid prototyping and rapid manufacturing, provides new opportunities in the manufacture of highly complex and custom-fitting medical devices and products. Whilst many medical applications of AM have been explored and physical properties of the resulting parts have been studied, the characterisation of AM materials in computed tomography has not been explored. The aim of this study was to determine the CT number of commonly used AM materials. There are many potential applications of the information resulting from this study in the design and manufacture of wearable medical devices, implants, prostheses and medical imaging test phantoms. A selection of 19 AM material samples were CT scanned and the resultant images analysed to ascertain the materials' CT number and appearance in the images. It was found that some AM materials have CT numbers very similar to human tissues, FDM, SLA and SLS produce samples that appear uniform on CT images and that 3D printed materials show a variation in internal structure.

  17. REVIEW: X-ray computed tomography

    NASA Astrophysics Data System (ADS)

    Kalender, Willi A.

    2006-07-01

    X-ray computed tomography (CT), introduced into clinical practice in 1972, was the first of the modern slice-imaging modalities. To reconstruct images mathematically from measured data and to display and to archive them in digital form was a novelty then and is commonplace today. CT has shown a steady upward trend with respect to technology, performance and clinical use independent of predictions and expert assessments which forecast in the 1980s that it would be completely replaced by magnetic resonance imaging. CT not only survived but exhibited a true renaissance due to the introduction of spiral scanning which meant the transition from slice-by-slice imaging to true volume imaging. Complemented by the introduction of array detector technology in the 1990s, CT today allows imaging of whole organs or the whole body in 5 to 20 s with sub-millimetre isotropic resolution. This review of CT will proceed in chronological order focussing on technology, image quality and clinical applications. In its final part it will also briefly allude to novel uses of CT such as dual-source CT, C-arm flat-panel-detector CT and micro-CT. At present CT possibly exhibits a higher innovation rate than ever before. In consequence the topical and most recent developments will receive the greatest attention.

  18. Intraperitoneal tuberculous abscess: Computed tomography features

    PubMed Central

    Dong, Peng; Chen, Jing-Jing; Wang, Xi-Zhen; Wang, Ya-Qin

    2015-01-01

    AIM: To evaluate the computed tomography (CT) features of intraperitoneal tuberculous abscess (IPTA). METHODS: Eight patients with IPTA confirmed by pathology were analyzed retrospectively. The clinical symptoms, medical images, and surgical findings were evaluated. Involvement of the intestine, peritoneum, viscera, and lymph nodes was also assessed. RESULTS: All 8 patients had a history of abdominal discomfort for 1 to 6 mo. Physical examination revealed a palpable abdominal mass in 6 patients. Three patients had no evidence of pulmonary tuberculosis (TB). All IPTAs (11 abscesses) were seen as a multiseptated, peripherally enhanced, hypodense mass with enlarged, rim-enhanced lymph nodes. The largest abscess diameter ranged from 4.5 cm to 12.2 cm. CT showed 2 types of IPTA: Lymph node fusion and encapsulation. Of the 8 patients, one had liver tuberculosis and one had splenic and ovarian tuberculosis. Two cases showed involvement of the terminal ileum and ileocecal junction. Ascites were found in 4 cases. Three patients had peritonitis and mesenteritis. Three patients showed involvement of the omentum. Three patients had histological evidence of caseating granuloma, and 5 had histological evidence of acid-fast bacilli. CONCLUSION: CT is crucial in the detection and characterization of IPTA. Certain CT findings are necessary for correct diagnosis. PMID:26435779

  19. Computed tomography imaging and angiography - principles.

    PubMed

    Kamalian, Shervin; Lev, Michael H; Gupta, Rajiv

    2016-01-01

    The evaluation of patients with diverse neurologic disorders was forever changed in the summer of 1973, when the first commercial computed tomography (CT) scanners were introduced. Until then, the detection and characterization of intracranial or spinal lesions could only be inferred by limited spatial resolution radioisotope scans, or by the patterns of tissue and vascular displacement on invasive pneumoencaphalography and direct carotid puncture catheter arteriography. Even the earliest-generation CT scanners - which required tens of minutes for the acquisition and reconstruction of low-resolution images (128×128 matrix) - could, based on density, noninvasively distinguish infarct, hemorrhage, and other mass lesions with unprecedented accuracy. Iodinated, intravenous contrast added further sensitivity and specificity in regions of blood-brain barrier breakdown. The advent of rapid multidetector row CT scanning in the early 1990s created renewed enthusiasm for CT, with CT angiography largely replacing direct catheter angiography. More recently, iterative reconstruction postprocessing techniques have made possible high spatial resolution, reduced noise, very low radiation dose CT scanning. The speed, spatial resolution, contrast resolution, and low radiation dose capability of present-day scanners have also facilitated dual-energy imaging which, like magnetic resonance imaging, for the first time, has allowed tissue-specific CT imaging characterization of intracranial pathology. PMID:27432657

  20. Shape threat detection via adaptive computed tomography

    NASA Astrophysics Data System (ADS)

    Masoudi, Ahmad; Thamvichai, Ratchaneekorn; Neifeld, Mark A.

    2016-05-01

    X-ray Computed Tomography (CT) is used widely for screening purposes. Conventional x-ray threat detection systems employ image reconstruction and segmentation algorithms prior to making threat/no-threat decisions. We find that in many cases these pre-processing steps can degrade detection performance. Therefore in this work we will investigate methods that operate directly on the CT measurements. We analyze a fixed-gantry system containing 25 x-ray sources and 2200 photon counting detectors. We present a new method for improving threat detection performance. This new method is a so-called greedy adaptive algorithm which at each time step uses information from previous measurements to design the next measurement. We utilize sequential hypothesis testing (SHT) in order to derive both the optimal "next measurement" and the stopping criterion to insure a target probability of error Pe. We find that selecting the next x-ray source according to such a greedy adaptive algorithm, we can reduce Pe by a factor of 42.4× relative to the conventional measurement sequence employing all 25 sources in sequence.

  1. Portable Digital Radiography and Computed Tomography Manual

    SciTech Connect

    Not Available

    2007-11-01

    This user manual describes the function and use of the portable digital radiography and computed tomography (DRCT) scanner. The manual gives a general overview of x-ray imaging systems along with a description of the DRCT system. An inventory of the all the system components, organized by shipping container, is also included. In addition, detailed, step-by-step procedures are provided for all of the exercises necessary for a novice user to successfully collect digital radiographs and tomographic images of an object, including instructions on system assembly and detector calibration and system alignment. There is also a short section covering the limited system care and maintenance needs. Descriptions of the included software packages, the DRCT Digital Imager used for system operation, and the DRCT Image Processing Interface used for image viewing and tomographic data reconstruction are given in the appendixes. The appendixes also include a cheat sheet for more experienced users, a listing of known system problems and how to mitigate them, and an inventory check-off sheet suitable for copying and including with the machine for shipment purposes.

  2. Three energy computed tomography with synchrotron radiation

    SciTech Connect

    Menk, R.H.; Thomlinson, W.; Zhong, Z.; Charvet, A.M.; Arfelli, F. |; Chapman, L.

    1997-09-01

    Preliminary experiments for digital subtraction computed tomography (CT) at the K-edge of iodine (33.1 keV) were carried out at SMERF (Synchrotron Medical Research Facility X17B2) at the National Synchrotron Light Source, Brookhaven National Laboratory. The major goal was to evaluate the availability of this kind of imaging for in vivo neurological studies. Using the transvenous coronary angiography system, CT images of various samples and phantoms were taken simultaneously at two slightly different energies bracketing the K-absorption edge of iodine. The logarithmic subtraction of the two images resulted in the contrast enhancement of iodine filled structures. An additional CT image was taken at 99.57 keV (second harmonic of the fundamental wave). The third energy allowed the calculation of absolute iodine, tissue and bone images by means of a matrix inversion. A spatial resolution of 0.8 LP/mm was measured in single energy images and iodine concentrations down to 0.082 mg/ml in a 1/4 diameter detail were visible in the reconstructed subtraction image.

  3. Perfusion computed tomography in renal cell carcinoma

    PubMed Central

    Das, Chandan J; Thingujam, Usha; Panda, Ananya; Sharma, Sanjay; Gupta, Arun Kumar

    2015-01-01

    Various imaging modalities are available for the diagnosis, staging and response evaluation of patients with renal cell carcinoma (RCC). While contrast enhanced computed tomography (CT) is used as the standard of imaging for size, morphological evaluation and response assessment in RCC, a new functional imaging technique like perfusion CT (pCT), goes down to the molecular level and provides new perspectives in imaging of RCC. pCT depicts regional tumor perfusion and vascular permeability which are indirect parameters of tumor angiogenesis and thereby provides vital information regarding tumor microenvironment. Also response evaluation using pCT may predate the size criteria used in Response Evaluation Criteria in Solid Tumors, as changes in the perfusion occurs earlier following tissue kinase inhibitors before any actual change in size. This may potentially help in predicting prognosis, better selection of therapy and more accurate and better response evaluation in patients with RCC. This article describes the techniques and role of pCT in staging and response assessment in patients with RCCs. PMID:26217456

  4. Dedicated breast computed tomography: Basic aspects

    SciTech Connect

    Sarno, Antonio; Mettivier, Giovanni Russo, Paolo

    2015-06-15

    X-ray mammography of the compressed breast is well recognized as the “gold standard” for early detection of breast cancer, but its performance is not ideal. One limitation of screening mammography is tissue superposition, particularly for dense breasts. Since 2001, several research groups in the USA and in the European Union have developed computed tomography (CT) systems with digital detector technology dedicated to x-ray imaging of the uncompressed breast (breast CT or BCT) for breast cancer screening and diagnosis. This CT technology—tracing back to initial studies in the 1970s—allows some of the limitations of mammography to be overcome, keeping the levels of radiation dose to the radiosensitive breast glandular tissue similar to that of two-view mammography for the same breast size and composition. This paper presents an evaluation of the research efforts carried out in the invention, development, and improvement of BCT with dedicated scanners with state-of-the-art technology, including initial steps toward commercialization, after more than a decade of R and D in the laboratory and/or in the clinic. The intended focus here is on the technological/engineering aspects of BCT and on outlining advantages and limitations as reported in the related literature. Prospects for future research in this field are discussed.

  5. Important advances in technology and unique applications to cardiovascular computed tomography.

    PubMed

    Chaikriangkrai, Kongkiat; Choi, Su Yeon; Nabi, Faisal; Chang, Su Min

    2014-01-01

    For the past decade, multidetector cardiac computed tomography and its main application, coronary computed tomography angiography, have been established as a noninvasive technique for anatomical assessment of coronary arteries. This new era of coronary artery evaluation by coronary computed tomography angiography has arisen from the rapid advancement in computed tomography technology, which has led to massive diagnostic and prognostic clinical studies in various patient populations. This article gives a brief overview of current multidetector cardiac computed tomography systems, developing cardiac computed tomography technologies in both hardware and software fields, innovative radiation exposure reduction measures, multidetector cardiac computed tomography functional studies, and their newer clinical applications beyond coronary computed tomography angiography. PMID:25574342

  6. Acute Calculous Cholecystitis Missed on Computed Tomography and Ultrasound but Diagnosed with Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography

    PubMed Central

    Aparici, Carina Mari; Win, Aung Zaw

    2016-01-01

    We present a case of a 69-year-old patient who underwent ascending aortic aneurysm repair with aortic valve replacement. On postsurgical day 12, he developed leukocytosis and low-grade fevers. The chest computed tomography (CT) showed a periaortic hematoma which represents a postsurgical change from aortic aneurysm repair, and a small pericardial effusion. The abdominal ultrasound showed cholelithiasis without any sign of cholecystitis. Finally, a fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT examination was ordered to find the cause of fever of unknown origin, and it showed increased FDG uptake in the gallbladder wall, with no uptake in the lumen. FDG-PET/CT can diagnose acute cholecystitis in patients with nonspecific clinical symptoms and laboratory results. PMID:27625897

  7. Acute Calculous Cholecystitis Missed on Computed Tomography and Ultrasound but Diagnosed with Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography.

    PubMed

    Aparici, Carina Mari; Win, Aung Zaw

    2016-01-01

    We present a case of a 69-year-old patient who underwent ascending aortic aneurysm repair with aortic valve replacement. On postsurgical day 12, he developed leukocytosis and low-grade fevers. The chest computed tomography (CT) showed a periaortic hematoma which represents a postsurgical change from aortic aneurysm repair, and a small pericardial effusion. The abdominal ultrasound showed cholelithiasis without any sign of cholecystitis. Finally, a fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT examination was ordered to find the cause of fever of unknown origin, and it showed increased FDG uptake in the gallbladder wall, with no uptake in the lumen. FDG-PET/CT can diagnose acute cholecystitis in patients with nonspecific clinical symptoms and laboratory results. PMID:27625897

  8. Acute Calculous Cholecystitis Missed on Computed Tomography and Ultrasound but Diagnosed with Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography

    PubMed Central

    Aparici, Carina Mari; Win, Aung Zaw

    2016-01-01

    We present a case of a 69-year-old patient who underwent ascending aortic aneurysm repair with aortic valve replacement. On postsurgical day 12, he developed leukocytosis and low-grade fevers. The chest computed tomography (CT) showed a periaortic hematoma which represents a postsurgical change from aortic aneurysm repair, and a small pericardial effusion. The abdominal ultrasound showed cholelithiasis without any sign of cholecystitis. Finally, a fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT examination was ordered to find the cause of fever of unknown origin, and it showed increased FDG uptake in the gallbladder wall, with no uptake in the lumen. FDG-PET/CT can diagnose acute cholecystitis in patients with nonspecific clinical symptoms and laboratory results.

  9. Non-uniform projection angle processing in computed tomography

    NASA Astrophysics Data System (ADS)

    Simo, Yanic; Tayag, Tristan J.

    In this paper, we present a novel approach for the collection of computed tomography data. Non-uniform increments in projection angle may be used to reduce data acquisition time with minimal reduction in the accuracy of the reconstructed profile. The key is to exploit those projection angles which correspond to regions where the object contains few high spatial frequency components. This technique is applicable to optical phase computed tomography, as well as X-ray computed tomography. We present simulation results on intraocular lenses used in cataract surgery.

  10. Abdominal alterations in disseminated paracoccidioidomycosis: computed tomography findings*

    PubMed Central

    Vermelho, Marli Batista Fernandes; Correia, Ademir Silva; Michailowsky, Tânia Cibele de Almeida; Suzart, Elizete Kazumi Kuniyoshi; Ibanês, Aline Santos; Almeida, Lanamar Aparecida; Khoury, Zarifa; Barba, Mário Flores

    2015-01-01

    Objective To evaluate the incidence and spectrum of abdominal computed tomography imaging findings in patients with paracoccidioidomycosis. Materials and Methods Retrospective analysis of abdominal computed tomography images of 26 patients with disseminated paracoccidioidomycosis. Results Abnormal abdominal tomographic findings were observed in 18 patients (69.2%), while no significant finding was observed in the other 8 (30.8%) patients. Conclusion Computed tomography has demonstrated to play a relevant role in the screening and detection of abdominal abnormalities in patients with disseminated paracoccidioidomycosis. PMID:25987748

  11. Simulation study of respiratory-induced errors in cardiac positron emission tomography/computed tomography

    SciTech Connect

    Fitzpatrick, Gianna M.; Wells, R. Glenn

    2006-08-15

    Heart disease is a leading killer in Canada and positron emission tomography (PET) provides clinicians with in vivo metabolic information for diagnosing heart disease. Transmission data are usually acquired with {sup 68}Ge, although the advent of PET/CT scanners has made computed tomography (CT) an alternative option. The fast data acquisition of CT compared to PET may cause potential misregistration problems, leading to inaccurate attenuation correction (AC). Using Monte Carlo simulations and an anthropomorphic dynamic computer phantom, this study determines the magnitude and location of respiratory-induced errors in radioactivity uptake measured in cardiac PET/CT. A homogeneous tracer distribution in the heart was considered. The AC was based on (1) a time-averaged attenuation map (2) CT maps from a single phase of the respiratory cycle, and (3) CT maps phase matched to the emission data. Circumferential profiles of the heart uptake were compared and differences of up to 24% were found between the single-phase CT-AC method and the true phantom values. Simulation results were supported by a PET/CT canine study which showed differences of up to 10% in the heart uptake in the lung-heart boundary region when comparing {sup 68}Ge- to CT-based AC with the CT map acquired at end inhalation.

  12. Computational reacting gas dynamics

    NASA Technical Reports Server (NTRS)

    Lam, S. H.

    1993-01-01

    In the study of high speed flows at high altitudes, such as that encountered by re-entry spacecrafts, the interaction of chemical reactions and other non-equilibrium processes in the flow field with the gas dynamics is crucial. Generally speaking, problems of this level of complexity must resort to numerical methods for solutions, using sophisticated computational fluid dynamics (CFD) codes. The difficulties introduced by reacting gas dynamics can be classified into three distinct headings: (1) the usually inadequate knowledge of the reaction rate coefficients in the non-equilibrium reaction system; (2) the vastly larger number of unknowns involved in the computation and the expected stiffness of the equations; and (3) the interpretation of the detailed reacting CFD numerical results. The research performed accepts the premise that reacting flows of practical interest in the future will in general be too complex or 'untractable' for traditional analytical developments. The power of modern computers must be exploited. However, instead of focusing solely on the construction of numerical solutions of full-model equations, attention is also directed to the 'derivation' of the simplified model from the given full-model. In other words, the present research aims to utilize computations to do tasks which have traditionally been done by skilled theoreticians: to reduce an originally complex full-model system into an approximate but otherwise equivalent simplified model system. The tacit assumption is that once the appropriate simplified model is derived, the interpretation of the detailed numerical reacting CFD numerical results will become much easier. The approach of the research is called computational singular perturbation (CSP).

  13. Recent Scientific Evidence and Technical Developments in Cardiovascular Computed Tomography.

    PubMed

    Marcus, Roy; Ruff, Christer; Burgstahler, Christof; Notohamiprodjo, Mike; Nikolaou, Konstantin; Geisler, Tobias; Schroeder, Stephen; Bamberg, Fabian

    2016-05-01

    In recent years, coronary computed tomography angiography has become an increasingly safe and noninvasive modality for the evaluation of the anatomical structure of the coronary artery tree with diagnostic benefits especially in patients with a low-to-intermediate pretest probability of disease. Currently, increasing evidence from large randomized diagnostic trials is accumulating on the diagnostic impact of computed tomography angiography for the management of patients with acute and stable chest pain syndrome. At the same time, technical advances have substantially reduced adverse effects and limiting factors, such as radiation exposure, the amount of iodinated contrast agent, and scanning time, rendering the technique appropriate for broader clinical applications. In this work, we review the latest developments in computed tomography technology and describe the scientific evidence on the use of cardiac computed tomography angiography to evaluate patients with acute and stable chest pain syndrome.

  14. Computed tomography of the liver in von Gierke's disease.

    PubMed

    Biondetti, P R; Fiore, D; Muzzio, P C

    1980-10-01

    The computed tomography findings in the liver of a patient with von Gierke's disease are presented. Precontrast scans demonstrated diffuse decreased density throughout the liver. In the postcontrast scans, a focal right sided hyperdense area was visualized. PMID:6931833

  15. Use of computed tomography in nondestructive testing of polymeric materials

    SciTech Connect

    Persson, S.; Oestman, E.

    1985-12-01

    Computed tomography has been used to detect imperfections and to measure cross-link density gradients in polymeric products, such as airplane tires, rubber shock absorbers, and filament-wound high-pressure tanks.

  16. Atlas of computed body tomography: normal and abnormal anatomy

    SciTech Connect

    Chiu, L.C.; Schapiro, R.L.

    1980-01-01

    This atlas contains comparative sections on normal and abnormal computed tomography of the neck, chest, abdomen, pelvis, upper and lower limbs, fascia, and peritoneum. Also included is a subject index to aid in the identification of abnormal scans. (DLS)

  17. Recent Scientific Evidence and Technical Developments in Cardiovascular Computed Tomography.

    PubMed

    Marcus, Roy; Ruff, Christer; Burgstahler, Christof; Notohamiprodjo, Mike; Nikolaou, Konstantin; Geisler, Tobias; Schroeder, Stephen; Bamberg, Fabian

    2016-05-01

    In recent years, coronary computed tomography angiography has become an increasingly safe and noninvasive modality for the evaluation of the anatomical structure of the coronary artery tree with diagnostic benefits especially in patients with a low-to-intermediate pretest probability of disease. Currently, increasing evidence from large randomized diagnostic trials is accumulating on the diagnostic impact of computed tomography angiography for the management of patients with acute and stable chest pain syndrome. At the same time, technical advances have substantially reduced adverse effects and limiting factors, such as radiation exposure, the amount of iodinated contrast agent, and scanning time, rendering the technique appropriate for broader clinical applications. In this work, we review the latest developments in computed tomography technology and describe the scientific evidence on the use of cardiac computed tomography angiography to evaluate patients with acute and stable chest pain syndrome. PMID:27025303

  18. Perfusion computed tomography to assist decision making for stroke thrombolysis.

    PubMed

    Bivard, Andrew; Levi, Christopher; Krishnamurthy, Venkatesh; McElduff, Patrick; Miteff, Ferdi; Spratt, Neil J; Bateman, Grant; Donnan, Geoffrey; Davis, Stephen; Parsons, Mark

    2015-07-01

    The use of perfusion imaging to guide selection of patients for stroke thrombolysis remains controversial because of lack of supportive phase three clinical trial evidence. We aimed to measure the outcomes for patients treated with intravenous recombinant tissue plasminogen activator (rtPA) at a comprehensive stroke care facility where perfusion computed tomography was routinely used for thrombolysis eligibility decision assistance. Our overall hypothesis was that patients with 'target' mismatch on perfusion computed tomography would have improved outcomes with rtPA. This was a prospective cohort study of consecutive ischaemic stroke patients who fulfilled standard clinical/non-contrast computed tomography eligibility criteria for treatment with intravenous rtPA, but for whom perfusion computed tomography was used to guide the final treatment decision. The 'real-time' perfusion computed tomography assessments were qualitative; a large perfusion computed tomography ischaemic core, or lack of significant perfusion lesion-core mismatch were considered relative exclusion criteria for thrombolysis. Specific volumetric perfusion computed tomography criteria were not used for the treatment decision. The primary analysis compared 3-month modified Rankin Scale in treated versus untreated patients after 'off-line' (post-treatment) quantitative volumetric perfusion computed tomography eligibility assessment based on presence or absence of 'target' perfusion lesion-core mismatch (mismatch ratio >1.8 and volume >15 ml, core <70 ml). In a second analysis, we compared outcomes of the perfusion computed tomography-selected rtPA-treated patients to an Australian historical cohort of non-contrast computed tomography-selected rtPA-treated patients. Of 635 patients with acute ischaemic stroke eligible for rtPA by standard criteria, thrombolysis was given to 366 patients, with 269 excluded based on visual real-time perfusion computed tomography assessment. After off-line quantitative

  19. Computed Tomography Staging of Middle Ear Cholesteatoma

    PubMed Central

    Razek, Ahmed Abdel Khalek Abdel; Ghonim, Mohamed Rashad; Ashraf, Bassem

    2015-01-01

    Summary Background To establish computed tomography (CT) staging of middle ear cholesteatoma and assess its impact on the selection of the surgical procedure. Material/Methods Prospective study was conducted on 61 consecutive patients (mean age 26.8 years) with middle ear cholesteatoma. CT scan of the temporal bone and surgery were performed in all patients. CT staging classified cholesteatoma according to its location in the tympanic cavity (T); extension into the mastoid (M); and associated complications (C). Cholesteatoma was staged as stage I (T1, T2), stage II (T3, M1, M2, C1), and stage III (C2). Results The overall sensitivity of CT staging of cholesteatoma compared to surgery was 88% with excellent agreement and correlation between CT findings and intra-operative findings (K=0.863, r=0.86, P=0.001). There was excellent agreement and correlation of CT staging with surgical findings for T location (K=0.811, r=0.89, P=0.001), good for M extension (K=0.734, r=0.88, P=0.001), and excellent for associated C complications (K=1.00, r=1.0, P=0.001). Atticotympanotomy was carried out in stage I (n=14), intact canal wall surgery was performed in stage II (n=38), and canal wall down surgery was done in stage III (n=5) and stage II (n=4). Conclusions We established CT staging of middle ear cholesteatoma that helps surgeons to select an appropriate surgery. PMID:26171086

  20. Dose in x-ray computed tomography

    NASA Astrophysics Data System (ADS)

    Kalender, Willi A.

    2014-02-01

    Radiation dose in x-ray computed tomography (CT) has become a topic of high interest due to the increasing numbers of CT examinations performed worldwide. This review aims to present an overview of current concepts for both scanner output metrics and for patient dosimetry and will comment on their strengths and weaknesses. Controversial issues such as the appropriateness of the CT dose index (CTDI) are discussed in detail. A review of approaches to patient dose assessment presently in practice, of the dose levels encountered and options for further dose optimization are also given and discussed. Patient dose assessment remains a topic for further improvement and for international consensus. All approaches presently in use are based on Monte Carlo (MC) simulations. Estimates for effective dose are established, but they are crude and not patient-specific; organ dose estimates are rarely available. Patient- and organ-specific dose estimates can be provided with adequate accuracy and independent of CTDI phantom measurements by fast MC simulations. Such information, in particular on 3D dose distributions, is important and helpful in optimization efforts. Dose optimization has been performed very successfully in recent years and even resulted in applications with effective dose values of below 1 mSv. In general, a trend towards lower dose values based on technical innovations has to be acknowledged. Effective dose values are down to clearly below 10 mSv on average, and there are a number of applications such as cardiac and pediatric CT which are performed routinely below 1 mSv on modern equipment.

  1. Detection of Foreign Bodies by Spiral Computed Tomography and Cone Beam Computed Tomography in Maxillofacial Regions

    PubMed Central

    Kaviani, Farzaneh; Javad Rashid, Reza; Shahmoradi, Zahra; Gholamian, Masoud

    2014-01-01

    Background and aims. The imaging techniques commonly used for foreign body detection include plain radiography, xeroradiography, computed tomography (CT) scans, magnetic resonance imaging (MRI) and ultrasonography. The aim of the present study was to compare cone-beam computed tomography (CBCT) with conventional CT scan in determination of the exact location of a foreign body in the maxillofacial area in vitro. Materials and methods. In this descriptive study, seven different materials were selected as foreign bodies with dimensions of approximately 2 mm, 1 mm, and 0.5 mm. These materials consisted of metal, glass, wood, stone, plastic, graphite and tooth. These foreign bodies were placed in a sheep head between the corpus of the mandible and muscle, in the tongue and in an air space. One conventional CT scan and two CBCT scans were made on the models. Results. Tooth, metal, stone and glass foreign bodies were seen clearly on CT and CBCT scans made by NewTom at the smallest size in air. However, CBCT scan by NewTom was a more effective technique for visualization of foreign bodies in air compared to conventional CT. Foreign bodies measuring 0.5 mm made of metal, stone, glass, graphite and teeth were detected by all devices in muscle tissue and adjacent bone. Conclusion. According to the results, CBCT scans of NewTom and Planmeca are appropriate tools for detecting foreign bodies with relative high density in the maxillofacial area. PMID:25346836

  2. Image analysis of particle field by means of computed tomography

    NASA Technical Reports Server (NTRS)

    Nakayama, Mitsushige

    1987-01-01

    In order to visualize and investigate spray structures, computed tomography technique is applied to analyze droplet information. From the transmitted light intensity through the spray and/or the data of particle size distribution obtained from a Fraunhofer diffraction principle, the quantitative volume of spray droplet or local particle size was calculated and the reconstruction of spray structures was made. The background of computed tomography is described along with some experimental results of the structure of intermittent spray such as diesel spray.

  3. Simulation of an interferometric computed tomography system for intraocular lenses

    NASA Astrophysics Data System (ADS)

    Tayag, Tristan J.; Bachim, Brent L.

    2010-08-01

    In this paper, we present a metrology system to characterize the refractive index profile of intraocular lenses (IOLs). Our system is based on interferometric optical phase computed tomography. We believe this metrology system to be a key enabling technology in the development of the next generation of IOLs. We propose a Fizeau-based optical configuration and present a simulation study on the application of computed tomography to IOL characterization.

  4. Multiple Energy Computer Tomography (MECT) at the NSLS: Status report

    SciTech Connect

    Dilmanian, F.A.; Wu, X.Y.; Chen, Z.; Ren, B.; Slatkin, D.N.; Chapman, D.; Schleifer, M.; Staicu, F.A.; Thomlinson, W.

    1994-09-01

    Status of the synchrotron-based computed tomography (CT) system Multiple Energy Computed Tomography (MECT) system is described. MECT, that uses monochromatic beams from the X17 superconducting wiggler beam line at the National Synchrotron Light Source (NSLS), will be used for imaging the human head and neck. An earlier prototype MECT produced images of phantoms and living rodents. This report summarizes the studies with the prototype, and describes the design, construction, and test results of the Clinical MECT system components.

  5. Computed tomography in evolution of testicular cancer during intensive chemotherapy.

    PubMed

    Javadpour, N; Anderson, T; Doppman, J L

    1979-10-01

    The evolution of malignant testicular tumor to mature teratoma has been studied in 4 patients. Computed tomography has been helpful in early diagnosis of this biologic phenomenon in these patients receiving intensive chemotherapy for disseminated non-seminomatous testicular cancer. Although the potential significance of this conversion in terms of survival is not known its early recognition by computed tomography has been useful in selecting and monitoring the therapy of these patients.

  6. Dynamics of bubble-bubble interaction in sheared low-viscosity magma imaged by X-ray computed micro-tomography

    NASA Astrophysics Data System (ADS)

    Helo, C.; Flaws, A.; Hess, K.-U.; Franz, A.; Clague, D. A.; Dingwell, D. B.

    2012-04-01

    X-ray computed tomography of vesicles in basaltic pyroclastic glass fragments has been used to investigate the syn-eruptive shear environment and resulting bubble-bubble interaction during mild pyroclastic eruptions in a mid-ocean ridge environment. We have imaged vesicles present in two different types of pyroclastic fragments produced by mildly explosive activity on Axial Seamount, limu o Pele, that is, thin glass films often described as bubble walls, and tube scoria fragments. Rapid quenching of the glass has prevented extensive bubble relaxation preserving the syn-eruptive geometry of the bubbles in these fragments. Isolated, ellipsoid-shaped vesicles in low-vesicular limu o Pele indicate deformation in a simple shear environment. Under these shear conditions higher vesiculated parts of the erupting magma show strong bubble-bubble interactions partially leading to coalscence and formation of tubular vesicles. These tubular vesicles can reach significant lengths, exceeding the dimensions of the small glass fragments (2 mm). Their unreformed radius can be more then one order of magnitude larger than that of the isolated vesicles in the limu o Pele fragments. We can distinguish two principle modes of interaction based on the relative orientation of the bubbles. Interaction along the sidewalls of two bubbles, and tip-to-tip interaction. At interdistances of less than a few tens of micrometre, interaction of the sidewalls results in deformation of the bubbles to more irregular shapes, with depressions caused by close, small bubbles or in some cases bubbles being partially mantled around tubular bubbles. This often leads to a more close packing of bubbles. At distances of less than a few microns, the melt films between the bubbles destabilize leading to coalescence. This mechanism appears to involve a bulging of the larger bubble into the smaller, followed by melt film rapture and coalescence. The complete digestion of one bubble by the other is the slow rate

  7. Application of Computer Tomography for Life Detection

    NASA Technical Reports Server (NTRS)

    Tsapin, A.; Nealson, K.

    2001-01-01

    Perhaps one of the most fundamentally difficult challenges facing those who would search for life is that of scale determination. Spatial scales of life on Earth range over more than 15 orders of magnitude in mass and volume, and more than 8 orders of magnitude in 2 dimensional space. If the distribution of life is sparse in comparison to the background on which it is found, then the choice of the right scale is critical to finding that life. But how does one identify the proper scale? To put this in other words, how does one recognize the "haystacks" in which the needles (biosignatures and evidence of life) might be most profitably searched for? The problem is further exacerbated when conditions get extreme because much of the life moves from the clement surface environment into the pores and more clement environments inside of rocks, minerals and soils. Once encased in their lithic homes, these microbes become nearly impossible to study by standard techniques because of the opacity of the rocks. It is this problem that we propose to address in the work proposed here. Computer Tomography (CT) has been a very valuable tool in medicine, where the best resolution available has typically been of the order of about 0.5 mm. However, to adapt the approach for life detection of microbial endoliths, the resolution needs to be moved to the micrometer and even submicrometer levels. Thus for the studies proposed here, we begin with a commercially available instrument that can yield resolution of approximately 10 micrometers. The rational for this is twofold: first, this is the "state of the art" in laboratory instruments; and second, that while the usual size of a microbial cell is about 1 micron, microorganisms tend to live in communities that usually exceed the 10 micrometer size range. The resolution also depends on the sample size itself, so having a small lab instrument into which small samples can be placed will be beneficial to the resolution. We have now used several

  8. Skeletal dosimetry in cone beam computed tomography

    SciTech Connect

    Walters, B. R. B.; Ding, G. X.; Kramer, R.; Kawrakow, I.

    2009-07-15

    Cone beam computed tomography (CBCT) is a relatively new patient imaging technique that has proved invaluable for treatment target verification and patient positioning during image-guided radiotherapy (IGRT). It has been shown that CBCT results in additional dose to bone that may amount to 10% of the prescribed dose. In this study, voxelized human phantoms, FAX06 (adult female) and MAX06 (adult male), are used together with phase-space data collected from a realistic model of a CBCT imager to calculate dose in the red bone marrow (RBM) and bone surface cells (BSCs), the two organs at risk within the bone spongiosa, during simulated head and neck, chest and pelvis CBCT scans. The FAX06/MAX06 phantoms model spongiosa based on micro-CT images, filling the relevant phantom voxels, which are 0.12x0.12x0.12 cm{sup 3}, with 17x17x17 {mu}m{sup 3} microvoxels to form a micromatrix of trabecular bone and bone marrow. FAX06/MAX06 have already been implemented in an EGSnrc-based Monte Carlo code to simulate radiation transport in the phantoms; however, this study required significant modifications of the code to allow use of phase-space data from a simulated CBCT imager as a source and to allow scoring of total dose, RBM dose and BSC dose on a voxel-by-voxel basis. In simulated CBCT scans, the BSC dose is significantly greater than the dose to other organs at risk. For example, in a simulated head and neck scan, the average BSC dose is 25% higher than the average dose to eye lens ({approx}8.3 cGy), and 80% greater than the average dose to brain (5.7 cGy). Average dose to RBM, on the other hand, is typically only {approx}50% of the average BSC dose and less than the dose to other organs at risk (54% of the dose to eye lens and 76% of dose to brain in a head and neck scan). Thus, elevated dose in bone due to CBCT results in elevated BSC dose. This is potentially of concern when using CBCT in conjunction with radiotherapy treatment.

  9. Computational fluid dynamic applications

    SciTech Connect

    Chang, S.-L.; Lottes, S. A.; Zhou, C. Q.

    2000-04-03

    The rapid advancement of computational capability including speed and memory size has prompted the wide use of computational fluid dynamics (CFD) codes to simulate complex flow systems. CFD simulations are used to study the operating problems encountered in system, to evaluate the impacts of operation/design parameters on the performance of a system, and to investigate novel design concepts. CFD codes are generally developed based on the conservation laws of mass, momentum, and energy that govern the characteristics of a flow. The governing equations are simplified and discretized for a selected computational grid system. Numerical methods are selected to simplify and calculate approximate flow properties. For turbulent, reacting, and multiphase flow systems the complex processes relating to these aspects of the flow, i.e., turbulent diffusion, combustion kinetics, interfacial drag and heat and mass transfer, etc., are described in mathematical models, based on a combination of fundamental physics and empirical data, that are incorporated into the code. CFD simulation has been applied to a large variety of practical and industrial scale flow systems.

  10. Endocrine radionuclide scintigraphy with fusion single photon emission computed tomography/computed tomography

    PubMed Central

    Wong, Ka-Kit; Gandhi, Arpit; Viglianti, Benjamin L; Fig, Lorraine M; Rubello, Domenico; Gross, Milton D

    2016-01-01

    AIM: To review the benefits of single photon emission computed tomography (SPECT)/computed tomography (CT) hybrid imaging for diagnosis of various endocrine disorders. METHODS: We performed MEDLINE and PubMed searches using the terms: “SPECT/CT”; “functional anatomic mapping”; “transmission emission tomography”; “parathyroid adenoma”; “thyroid cancer”; “neuroendocrine tumor”; “adrenal”; “pheochromocytoma”; “paraganglioma”; in order to identify relevant articles published in English during the years 2003 to 2015. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved manuscripts (case reports, reviews, meta-analyses and abstracts) concerning the application of SPECT/CT to endocrine imaging were analyzed to provide a descriptive synthesis of the utility of this technology. RESULTS: The emergence of hybrid SPECT/CT camera technology now allows simultaneous acquisition of combined multi-modality imaging, with seamless fusion of three-dimensional volume datasets. The usefulness of combining functional information to depict the bio-distribution of radiotracers that map cellular processes of the endocrine system and tumors of endocrine origin, with anatomy derived from CT, has improved the diagnostic capability of scintigraphy for a range of disorders of endocrine gland function. The literature describes benefits of SPECT/CT for 99mTc-sestamibi parathyroid scintigraphy and 99mTc-pertechnetate thyroid scintigraphy, 123I- or 131I-radioiodine for staging of differentiated thyroid carcinoma, 111In- and 99mTc- labeled somatostatin receptor analogues for detection of neuroendocrine tumors, 131I-norcholesterol (NP-59) scans for assessment of adrenal cortical hyperfunction, and 123I- or 131I-metaiodobenzylguanidine imaging for evaluation of pheochromocytoma and paraganglioma. CONCLUSION: SPECT/CT exploits the synergism between the functional information from radiopharmaceutical imaging and anatomy

  11. Computed tomography in the evaluation of Crohn disease

    SciTech Connect

    Goldberg, H.I.; Gore, R.M.; Margulis, A.R.; Moss, A.A.; Baker, E.L.

    1983-02-01

    The abdominal and pelvic computed tomographic examinations in 28 patients with Crohn disease were analyzed and correlated with conventional barium studies, sinograms, and surgical findings. Mucosal abnormalities such as aphthous lesions, pseudopolyps, and ulcerations were only imaged by conventional techniques. Computed tomography proved superior in demonstrating the mural, serosal, and mesenteric abnormalities such as bowel wall thickening (82%), fibrofatty proliferation of mesenteric fat (39%), mesenteric abscess (25%), inflammatory reaction of the mesentery (14%), and mesenteric lymphadenopathy (18%). Computed tomography was most useful clinically in defining the nature of mass effects, separation, or displacement of small bowel segments seen on small bowel series. Although conventional barium studies remain the initial diagnostic procedure in evaluating Crohn disease, computed tomography can be a useful adjunct in resolving difficult clinical and radiologic diagnostic problems.

  12. Development of a proton Computed Tomography detector system

    NASA Astrophysics Data System (ADS)

    Naimuddin, Md.; Coutrakon, G.; Blazey, G.; Boi, S.; Dyshkant, A.; Erdelyi, B.; Hedin, D.; Johnson, E.; Krider, J.; Rukalin, V.; Uzunyan, S. A.; Zutshi, V.; Fordt, R.; Sellberg, G.; Rauch, J. E.; Roman, M.; Rubinov, P.; Wilson, P.

    2016-02-01

    Computer tomography is one of the most promising new methods to image abnormal tissues inside the human body. Tomography is also used to position the patient accurately before radiation therapy. Hadron therapy for treating cancer has become one of the most advantegeous and safe options. In order to fully utilize the advantages of hadron therapy, there is a necessity of performing radiography with hadrons as well. In this paper we present the development of a proton computed tomography system. Our second-generation proton tomography system consists of two upstream and two downstream trackers made up of fibers as active material and a range detector consisting of plastic scintillators. We present details of the detector system, readout electronics, and data acquisition system as well as the commissioning of the entire system. We also present preliminary results from the test beam of the range detector.

  13. Domain identification in impedance computed tomography by spline collocation method

    NASA Technical Reports Server (NTRS)

    Kojima, Fumio

    1990-01-01

    A method for estimating an unknown domain in elliptic boundary value problems is considered. The problem is formulated as an inverse problem of integral equations of the second kind. A computational method is developed using a splice collocation scheme. The results can be applied to the inverse problem of impedance computed tomography (ICT) for image reconstruction.

  14. Evaluating iterative reconstruction performance in computed tomography

    SciTech Connect

    Chen, Baiyu Solomon, Justin; Ramirez Giraldo, Juan Carlos; Samei, Ehsan

    2014-12-15

    Purpose: Iterative reconstruction (IR) offers notable advantages in computed tomography (CT). However, its performance characterization is complicated by its potentially nonlinear behavior, impacting performance in terms of specific tasks. This study aimed to evaluate the performance of IR with both task-specific and task-generic strategies. Methods: The performance of IR in CT was mathematically assessed with an observer model that predicted the detection accuracy in terms of the detectability index (d′). d′ was calculated based on the properties of the image noise and resolution, the observer, and the detection task. The characterizations of image noise and resolution were extended to accommodate the nonlinearity of IR. A library of tasks was mathematically modeled at a range of sizes (radius 1–4 mm), contrast levels (10–100 HU), and edge profiles (sharp and soft). Unique d′ values were calculated for each task with respect to five radiation exposure levels (volume CT dose index, CTDI{sub vol}: 3.4–64.8 mGy) and four reconstruction algorithms (filtered backprojection reconstruction, FBP; iterative reconstruction in imaging space, IRIS; and sinogram affirmed iterative reconstruction with strengths of 3 and 5, SAFIRE3 and SAFIRE5; all provided by Siemens Healthcare, Forchheim, Germany). The d′ values were translated into the areas under the receiver operating characteristic curve (AUC) to represent human observer performance. For each task and reconstruction algorithm, a threshold dose was derived as the minimum dose required to achieve a threshold AUC of 0.9. A task-specific dose reduction potential of IR was calculated as the difference between the threshold doses for IR and FBP. A task-generic comparison was further made between IR and FBP in terms of the percent of all tasks yielding an AUC higher than the threshold. Results: IR required less dose than FBP to achieve the threshold AUC. In general, SAFIRE5 showed the most significant dose reduction

  15. Gliomatosis cerebri mimicking encephalitis evaluated using fluorine-18 fluorodeoxyglucose: Positron emission tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Krishnan, Vijayan; Mohanan, Vyshakh; Shibu, Deepu; Shinto, Ajit Sugunan

    2015-01-01

    Gliomatosis cerebri (GC) is a rare condition in which an infiltrative glial neoplasm spreads through the brain with preservation of the underlying structure. F-18 fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) has an important role in demonstrating the appropriate metabolism and differentiating pathologies mimicking GC on CT and magnetic resonance imaging. We describe imaging findings of FDG PET/CT in GC in a 9-year-old male child mimicking encephalitis. PMID:25589818

  16. Gliomatosis cerebri mimicking encephalitis evaluated using fluorine-18 fluorodeoxyglucose: Positron emission tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Krishnan, Vijayan; Mohanan, Vyshakh; Shibu, Deepu; Shinto, Ajit Sugunan

    2015-01-01

    Gliomatosis cerebri (GC) is a rare condition in which an infiltrative glial neoplasm spreads through the brain with preservation of the underlying structure. F-18 fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) has an important role in demonstrating the appropriate metabolism and differentiating pathologies mimicking GC on CT and magnetic resonance imaging. We describe imaging findings of FDG PET/CT in GC in a 9-year-old male child mimicking encephalitis.

  17. Pigmented villonodular synovitis mimics metastases on fluorine 18 fluorodeoxyglucose position emission tomography-computed tomography

    PubMed Central

    Elumogo, Comfort O.; Kochenderfer, James N.; Civelek, A. Cahid

    2016-01-01

    Pigmented villonodular synovitis (PVNS) is a benign joint disease best characterized on magnetic resonance imaging (MRI). The role of fluorine 18 fluorodeoxyglucose (18F-FDG) position emission tomography-computed tomography (PET-CT) in the diagnosis or characterization remains unclear. PVNS displays as a focal FDG avid lesion, which can masquerade as a metastatic lesion, on PET-CET. We present a case of PVNS found on surveillance imaging of a lymphoma patient. PMID:27190776

  18. Can 64-row computed tomography replace angiography after coronary bypass?

    PubMed

    Doi, Hirosato; Koshima, Ryuji; Suzuki, Masato; Takahashi, Ken; Yokoyama, Hiroichi; Yoshida, Naoya

    2008-12-01

    Multi-detector (64-row) computed tomography has become an alternative to coronary angiography to diagnose graft occlusion and stenosis after coronary artery bypass. We compared the power of evaluation of multi-detector computed tomography with that of conventional coronary angiography in 60 patients who underwent coronary artery bypass with 135 grafts and 210 graft anastomoses. The diagnostic power of multi-detector computed tomography for graft occlusion was: 100% (2/2) sensitivity, 98.5% (131/133) specificity, 50% (2/4) positive predictive value, and 100% (133/133) negative predictive value; there were no significant differences in rates of occlusion among the different types of graft. The diagnostic power of multi-detector computed tomography for stenosis of the graft anastomosis was: 100% (2/2) sensitivity, 95.1% (194/204) specificity, 16.6% (2/12) positive predictive value, and 100% (194/194) negative predictive value, with no significant differences among grafts. Multi-detector computed tomography permits evaluation of bypass grafts and is much less invasive for the patients. PMID:18984751

  19. Stress Computed Tomography Myocardial Perfusion Imaging: A New Topic in Cardiology.

    PubMed

    Seitun, Sara; Castiglione Morelli, Margherita; Budaj, Irilda; Boccalini, Sara; Galletto Pregliasco, Athena; Valbusa, Alberto; Cademartiri, Filippo; Ferro, Carlo

    2016-02-01

    Since its introduction about 15 years ago, coronary computed tomography angiography has become today the most accurate clinical instrument for noninvasive assessment of coronary atherosclerosis. Important technical developments have led to a continuous stream of new clinical applications together with a significant reduction in radiation dose exposure. Latest generation computed tomography scanners (≥ 64 slices) allow the possibility of performing static or dynamic perfusion imaging during stress by using coronary vasodilator agents (adenosine, dipyridamole, or regadenoson), combining both functional and anatomical information in the same examination. In this article, the emerging role and state-of-the-art of myocardial computed tomography perfusion imaging are reviewed and are illustrated by clinical cases from our experience with a second-generation dual-source 128-slice scanner (Somatom Definition Flash, Siemens; Erlangen, Germany). Technical aspects, data analysis, diagnostic accuracy, radiation dose and future prospects are reviewed.

  20. Stress Computed Tomography Myocardial Perfusion Imaging: A New Topic in Cardiology.

    PubMed

    Seitun, Sara; Castiglione Morelli, Margherita; Budaj, Irilda; Boccalini, Sara; Galletto Pregliasco, Athena; Valbusa, Alberto; Cademartiri, Filippo; Ferro, Carlo

    2016-02-01

    Since its introduction about 15 years ago, coronary computed tomography angiography has become today the most accurate clinical instrument for noninvasive assessment of coronary atherosclerosis. Important technical developments have led to a continuous stream of new clinical applications together with a significant reduction in radiation dose exposure. Latest generation computed tomography scanners (≥ 64 slices) allow the possibility of performing static or dynamic perfusion imaging during stress by using coronary vasodilator agents (adenosine, dipyridamole, or regadenoson), combining both functional and anatomical information in the same examination. In this article, the emerging role and state-of-the-art of myocardial computed tomography perfusion imaging are reviewed and are illustrated by clinical cases from our experience with a second-generation dual-source 128-slice scanner (Somatom Definition Flash, Siemens; Erlangen, Germany). Technical aspects, data analysis, diagnostic accuracy, radiation dose and future prospects are reviewed. PMID:26774540

  1. Dynamic light scattering optical coherence tomography

    PubMed Central

    Lee, Jonghwan; Wu, Weicheng; Jiang, James Y.; Zhu, Bo; Boas, David A.

    2012-01-01

    We introduce an integration of dynamic light scattering (DLS) and optical coherence tomography (OCT) for high-resolution 3D imaging of heterogeneous diffusion and flow. DLS analyzes fluctuations in light scattered by particles to measure diffusion or flow of the particles, and OCT uses coherence gating to collect light only scattered from a small volume for high-resolution structural imaging. Therefore, the integration of DLS and OCT enables high-resolution 3D imaging of diffusion and flow. We derived a theory under the assumption that static and moving particles are mixed within the OCT resolution volume and the moving particles can exhibit either diffusive or translational motion. Based on this theory, we developed a fitting algorithm to estimate dynamic parameters including the axial and transverse velocities and the diffusion coefficient. We validated DLS-OCT measurements of diffusion and flow through numerical simulations and phantom experiments. As an example application, we performed DLS-OCT imaging of the living animal brain, resulting in 3D maps of the absolute and axial velocities, the diffusion coefficient, and the coefficient of determination. PMID:23037374

  2. Acceleration of dynamic fluorescence molecular tomography with principal component analysis

    PubMed Central

    Zhang, Guanglei; He, Wei; Pu, Huangsheng; Liu, Fei; Chen, Maomao; Bai, Jing; Luo, Jianwen

    2015-01-01

    Dynamic fluorescence molecular tomography (FMT) is an attractive imaging technique for three-dimensionally resolving the metabolic process of fluorescent biomarkers in small animal. When combined with compartmental modeling, dynamic FMT can be used to obtain parametric images which can provide quantitative pharmacokinetic information for drug development and metabolic research. However, the computational burden of dynamic FMT is extremely huge due to its large data sets arising from the long measurement process and the densely sampling device. In this work, we propose to accelerate the reconstruction process of dynamic FMT based on principal component analysis (PCA). Taking advantage of the compression property of PCA, the dimension of the sub weight matrix used for solving the inverse problem is reduced by retaining only a few principal components which can retain most of the effective information of the sub weight matrix. Therefore, the reconstruction process of dynamic FMT can be accelerated by solving the smaller scale inverse problem. Numerical simulation and mouse experiment are performed to validate the performance of the proposed method. Results show that the proposed method can greatly accelerate the reconstruction of parametric images in dynamic FMT almost without degradation in image quality. PMID:26114027

  3. Continuous analog of multiplicative algebraic reconstruction technique for computed tomography

    NASA Astrophysics Data System (ADS)

    Tateishi, Kiyoko; Yamaguchi, Yusaku; Abou Al-Ola, Omar M.; Kojima, Takeshi; Yoshinaga, Tetsuya

    2016-03-01

    We propose a hybrid dynamical system as a continuous analog to the block-iterative multiplicative algebraic reconstruction technique (BI-MART), which is a well-known iterative image reconstruction algorithm for computed tomography. The hybrid system is described by a switched nonlinear system with a piecewise smooth vector field or differential equation and, for consistent inverse problems, the convergence of non-negatively constrained solutions to a globally stable equilibrium is guaranteed by the Lyapunov theorem. Namely, we can prove theoretically that a weighted Kullback-Leibler divergence measure can be a common Lyapunov function for the switched system. We show that discretizing the differential equation by using the first-order approximation (Euler's method) based on the geometric multiplicative calculus leads to the same iterative formula of the BI-MART with the scaling parameter as a time-step of numerical discretization. The present paper is the first to reveal that a kind of iterative image reconstruction algorithm is constructed by the discretization of a continuous-time dynamical system for solving tomographic inverse problems. Iterative algorithms with not only the Euler method but also the Runge-Kutta methods of lower-orders applied for discretizing the continuous-time system can be used for image reconstruction. A numerical example showing the characteristics of the discretized iterative methods is presented.

  4. Diagnosis of dementia with single photon emission computed tomography

    SciTech Connect

    Jagust, W.J.; Budinger, T.F.; Reed, B.R.

    1987-03-01

    Single photon emission computed tomography is a practical modality for the study of physiologic cerebral activity in vivo. We utilized single photon emission computed tomography and N-isopropyl-p-iodoamphetamine iodine 123 to evaluate regional cerebral blood flow in nine patients with Alzheimer's disease (AD), five healthy elderly control subjects, and two patients with multi-infarct dementia. We found that all subjects with AD demonstrated flow deficits in temporoparietal cortex bilaterally, and that the ratio of activity in bilateral temporoparietal cortex to activity in the whole slice allowed the differentiation of all patients with AD from both the controls and from the patients with multi-infarct dementia. Furthermore, this ratio showed a strong correlation with disease severity in the AD group. Single photon emission computed tomography appears to be useful in the differential diagnosis of dementia and reflects clinical features of the disease.

  5. Computational Fluid Dynamics Library

    2005-03-04

    CFDLib05 is the Los Alamos Computational Fluid Dynamics LIBrary. This is a collection of hydrocodes using a common data structure and a common numerical method, for problems ranging from single-field, incompressible flow, to multi-species, multi-field, compressible flow. The data structure is multi-block, with a so-called structured grid in each block. The numerical method is a Finite-Volume scheme employing a state vector that is fully cell-centered. This means that the integral form of the conservation lawsmore » is solved on the physical domain that is represented by a mesh of control volumes. The typical control volume is an arbitrary quadrilateral in 2D and an arbitrary hexahedron in 3D. The Finite-Volume scheme is for time-unsteady flow and remains well coupled by means of time and space centered fluxes; if a steady state solution is required, the problem is integrated forward in time until the user is satisfied that the state is stationary.« less

  6. Missing wedge computed tomography by iterative algorithm DIRECTT.

    PubMed

    Kupsch, Andreas; Lange, Axel; Hentschel, Manfred P; Lück, Sebastian; Schmidt, Volker; Grothausmann, Roman; Hilger, André; Manke, Ingo

    2015-01-01

    A strategy to mitigate typical reconstruction artefacts in missing wedge computed tomography is presented. These artefacts appear as elongations of reconstructed details along the mean direction (i.e. the symmetry centre of the projections). Although absent in standard computed tomography applications, they are most prominent in advanced electron tomography and also in special topics of X-ray and neutron tomography under restricted geometric boundary conditions. We investigate the performance of the DIRECTT (Direct Iterative Reconstruction of Computed Tomography Trajectories) algorithm to reduce the directional artefacts in standard procedures. In order to be sensitive to the anisotropic nature of missing wedge artefacts, we investigate isotropic substructures of metal foam as well as circular disc models. Comparison is drawn to filtered backprojection and algebraic techniques. Reference is made to reconstructions of complete data sets. For the purpose of assessing the reconstruction quality, Fourier transforms are employed to visualize the missing wedge directly. Deficient reconstructions of disc models are evaluated by a length-weighted kernel density estimation, which yields the probabilities of boundary orientations. The DIRECTT results are assessed at different signal-to-noise ratios by means of local and integral evaluation parameters. PMID:26367127

  7. Multiscale photoacoustic microscopy and computed tomography

    PubMed Central

    Wang, Lihong V.

    2009-01-01

    Photoacoustic tomography (PAT) is probably the fastest growing biomedical imaging technology owing to its capability of high-resolution sensing of rich optical contrast in vivo at depths beyond the optical transport mean free path (~1 mm in the skin). Existing high-resolution optical imaging technologies, such as confocal microscopy and two-photon microscopy, have fundamentally impacted biomedicine but cannot reach such depths. Taking advantage of low ultrasonic scattering, PAT indirectly improves tissue transparency by 100 to 1000 fold and consequently enables deeply penetrating functional and molecular imaging at high spatial resolution. Further, PAT holds the promise of in vivo imaging at multiple length scales ranging from subcellular organelles to organs with the same contrast origin, an important application in multiscale systems biology research. PMID:20161535

  8. An Exploratory Study Into the Role of Dynamic Contrast-Enhanced Magnetic Resonance Imaging or Perfusion Computed Tomography for Detection of Intratumoral Hypoxia in Head-and-Neck Cancer

    SciTech Connect

    Newbold, Kate Castellano, Isabel; Charles-Edwards, Elizabeth; Mears, Dorothy; Sohaib, Aslam; Leach, Martin; Rhys-Evans, Peter; Clarke, Peter; Fisher, Cyril; Harrington, Kevin; Nutting, Christopher

    2009-05-01

    Purpose: Hypoxia in patients with head-and-neck cancer (HNC) is well established and known to cause radiation resistance and treatment failure in the management of HNC. This study examines the role of parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and perfusion computed tomography (CT) as surrogate markers of intratumoral hypoxia, defined by using the exogenous marker of hypoxia pimonidazole and the endogenous marker carbonic anhydrase 9 (CA9). Methods and Materials: Patients with HNC underwent preoperative DCE-MRI, perfusion CT, and pimonidazole infusion. Imaging parameters were correlated with pimonidazole and CA9 staining. The strength of correlations was tested by using a two-tailed Spearman's rank correlation coefficient. Results: Twenty-three regions of interest were analyzed from the 7 patients who completed the DCE-MRI studies. A number of statistically significant correlations were seen between DCE-MRI parameters (volume transfer between blood plasma and extracellular extravascular space [EES], volume of EES, rate constant between EES and blood plasma, time at arrival of contrast inflow, time to peak, average gradient, and time to onset) and areas with a pimonidazole score of 4. In the case of CA9 staining, only a weak correlation was shown with wash-in rate. There were no significant correlations between perfusion CT parameters and pimonidazole staining or CA9 expression. Conclusion: Intratumoral hypoxia in patients with HNC may be predicted by using DCE-MRI; however, perfusion CT requires further investigation.

  9. Computed tomography: Will the slices reveal the truth

    PubMed Central

    Haridas, Harish; Mohan, Abarajithan; Papisetti, Sravanthi; Ealla, Kranti K. R.

    2016-01-01

    With the advances in the field of imaging sciences, new methods have been developed in dental radiology. These include digital radiography, density analyzing methods, cone beam computed tomography (CBCT), magnetic resonance imaging, ultrasound, and nuclear imaging techniques, which provide high-resolution detailed images of oral structures. The current review aims to critically elaborate the use of CBCT in endodontics.

  10. Computed tomography of the temporo-mandibular joint.

    PubMed

    Avrahami, E; Horowitz, I; Cohn, D F

    1984-01-01

    Computed tomography (CT) of the temporo-mandibular joint (TMJ) has only been occasionally reported. As CT techniques improve, more detailed information is available. Though conventional radiography of the TMJ can supply sufficient diagnostic detail, it may well be replaced by CT as a preliminary examination, as it is able to offer more information with less radiation and minimal patient discomfort.

  11. An Easily Assembled Laboratory Exercise in Computed Tomography

    ERIC Educational Resources Information Center

    Mylott, Elliot; Klepetka, Ryan; Dunlap, Justin C.; Widenhorn, Ralf

    2011-01-01

    In this paper, we present a laboratory activity in computed tomography (CT) primarily composed of a photogate and a rotary motion sensor that can be assembled quickly and partially automates data collection and analysis. We use an enclosure made with a light filter that is largely opaque in the visible spectrum but mostly transparent to the near…

  12. Evolution of the Cranial Computed Tomography Scan in Child Abuse.

    ERIC Educational Resources Information Center

    Feldman, Kenneth W.; And Others

    1995-01-01

    A retrospective review of medical charts for 34 children with a diagnosis of child abuse, who had cranial computed tomography scans performed, revealed that some scans initially interpreted as normal were subsequently reinterpreted as abnormal, and some children's repeat scannings were interpreted as abnormal, modifying the medical and legal…

  13. Computed tomography: Will the slices reveal the truth.

    PubMed

    Haridas, Harish; Mohan, Abarajithan; Papisetti, Sravanthi; Ealla, Kranti K R

    2016-08-01

    With the advances in the field of imaging sciences, new methods have been developed in dental radiology. These include digital radiography, density analyzing methods, cone beam computed tomography (CBCT), magnetic resonance imaging, ultrasound, and nuclear imaging techniques, which provide high-resolution detailed images of oral structures. The current review aims to critically elaborate the use of CBCT in endodontics. PMID:27652253

  14. Computed Tomography-Enhanced Anatomy Course Using Enterprise Visualization

    ERIC Educational Resources Information Center

    May, Hila; Cohen, Haim; Medlej, Bahaa; Kornreich, Liora; Peled, Nathan; Hershkovitz, Israel

    2013-01-01

    Rapid changes in medical knowledge are forcing continuous adaptation of the basic science courses in medical schools. This article discusses a three-year experience developing a new Computed Tomography (CT)-based anatomy curriculum at the Sackler School of Medicine, Tel Aviv University, including describing the motivations and reasoning for the…

  15. Computed tomography: Will the slices reveal the truth

    PubMed Central

    Haridas, Harish; Mohan, Abarajithan; Papisetti, Sravanthi; Ealla, Kranti K. R.

    2016-01-01

    With the advances in the field of imaging sciences, new methods have been developed in dental radiology. These include digital radiography, density analyzing methods, cone beam computed tomography (CBCT), magnetic resonance imaging, ultrasound, and nuclear imaging techniques, which provide high-resolution detailed images of oral structures. The current review aims to critically elaborate the use of CBCT in endodontics. PMID:27652253

  16. RADIAL COMPUTED TOMOGRAPHY OF AIR CONTAMINANTS USING OPTICAL REMOTE SENSING

    EPA Science Inventory

    The paper describes the application of an optical remote-sensing (ORS) system to map air contaminants and locate fugitive emissions. Many ORD systems may utilize radial non-overlapping beam geometry and a computed tomography (CT) algorithm to map the concentrations in a plane. In...

  17. [X-ray computed tomography in the diagnosis of mediastinitis].

    PubMed

    Abakumov, M M; Barmina, T G; Ishmukhametov, A I

    2001-01-01

    Results of X-ray computed tomography (RCT) use in 21 patients treated for acute mediastinitis in N.V. Sklifosovsky Emergency Care Research Institute have been analyzed retrospectively. RCT proved able to defect accurate location, spreading and sizes of inflammatory disorders in the mediastinum are demonstrated. Semiotics of mediastinitis depending on location, spreading and phase of inflammatory process is presented.

  18. Cone beam computed tomography scanning and diagnosis for dental implants.

    PubMed

    Greenberg, Alex M

    2015-05-01

    Cone beam computed tomography (CBCT) has become an important new technology for oral and maxillofacial surgery practitioners. CBCT provides improved office-based diagnostic capability and applications for surgical procedures, such as CT guidance through the use of computer-generated drill guides. A thorough knowledge of the basic science of CBCT as well as the ability to interpret the images correctly and thoroughly is essential to current practice.

  19. Computed tomography perfusion imaging denoising using Gaussian process regression

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    Brain perfusion weighted images acquired using dynamic contrast studies have an important clinical role in acute stroke diagnosis and treatment decisions. However, computed tomography (CT) images suffer from low contrast-to-noise ratios (CNR) as a consequence of the limitation of the exposure to radiation of the patient. As a consequence, the developments of methods for improving the CNR are valuable. The majority of existing approaches for denoising CT images are optimized for 3D (spatial) information, including spatial decimation (spatially weighted mean filters) and techniques based on wavelet and curvelet transforms. However, perfusion imaging data is 4D as it also contains temporal information. Our approach using Gaussian process regression (GPR), which takes advantage of the temporal information, to reduce the noise level. Over the entire image, GPR gains a 99% CNR improvement over the raw images and also improves the quality of haemodynamic maps allowing a better identification of edges and detailed information. At the level of individual voxel, GPR provides a stable baseline, helps us to identify key parameters from tissue time-concentration curves and reduces the oscillations in the curve. GPR is superior to the comparable techniques used in this study.

  20. Comparison of Computed Tomography Scout Based Reference Point Localization to Conventional Film and Axial Computed Tomography

    SciTech Connect

    Jiang Lan; Templeton, Alistair; Turian, Julius; Kirk, Michael; Zusag, Thomas; Chu, James C.H.

    2011-01-01

    Identification of source positions after implantation is an important step in brachytherapy planning. Reconstruction is traditionally performed from films taken by conventional simulators, but these are gradually being replaced in the clinic by computed tomography (CT) simulators. The present study explored the use of a scout image-based reconstruction algorithm that replaces the use of traditional film, while exhibiting low sensitivity to metal-induced artifacts that can appear in 3D CT methods. In addition, the accuracy of an in-house graphical software implementation of scout-based reconstruction was compared with seed location reconstructions for 2 phantoms by conventional simulator and CT measurements. One phantom was constructed using a planar fixed grid of 1.5-mm diameter ball bearings (BBs) with 40-mm spacing. The second was a Fletcher-Suit applicator embedded in Styrofoam (Dow Chemical Co., Midland, MI) with one 3.2-mm-diameter BB inserted into each of 6 surrounding holes. Conventional simulator, kilovoltage CT (kVCT), megavoltage CT, and scout-based methods were evaluated by their ability to calculate the distance between seeds (40 mm for the fixed grid, 30-120 mm in Fletcher-Suit). All methods were able to reconstruct the fixed grid distances with an average deviation of <1%. The worst single deviations (approximately 6%) were exhibited in the 2 volumetric CT methods. In the Fletcher-Suit phantom, the intermodality agreement was within approximately 3%, with the conventional sim measuring marginally larger distances, with kVCT the smallest. All of the established reconstruction methods exhibited similar abilities to detect the distances between BBs. The 3D CT-based methods, with lower axial resolution, showed more variation, particularly with the smaller BBs. With a software implementation, scout-based reconstruction is an appealing approach because it simplifies data acquisition over film-based reconstruction without requiring any specialized equipment

  1. Comparison of computed tomography scout based reference point localization to conventional film and axial computed tomography.

    PubMed

    Jiang, Lan; Templeton, Alistair; Turian, Julius; Kirk, Michael; Zusag, Thomas; Chu, James C H

    2011-01-01

    Identification of source positions after implantation is an important step in brachytherapy planning. Reconstruction is traditionally performed from films taken by conventional simulators, but these are gradually being replaced in the clinic by computed tomography (CT) simulators. The present study explored the use of a scout image-based reconstruction algorithm that replaces the use of traditional film, while exhibiting low sensitivity to metal-induced artifacts that can appear in 3D CT methods. In addition, the accuracy of an in-house graphical software implementation of scout-based reconstruction was compared with seed location reconstructions for 2 phantoms by conventional simulator and CT measurements. One phantom was constructed using a planar fixed grid of 1.5-mm diameter ball bearings (BBs) with 40-mm spacing. The second was a Fletcher-Suit applicator embedded in Styrofoam (Dow Chemical Co., Midland, MI) with one 3.2-mm-diameter BB inserted into each of 6 surrounding holes. Conventional simulator, kilovoltage CT (kVCT), megavoltage CT, and scout-based methods were evaluated by their ability to calculate the distance between seeds (40 mm for the fixed grid, 30-120 mm in Fletcher-Suit). All methods were able to reconstruct the fixed grid distances with an average deviation of <1%. The worst single deviations (approximately 6%) were exhibited in the 2 volumetric CT methods. In the Fletcher-Suit phantom, the intermodality agreement was within approximately 3%, with the conventional sim measuring marginally larger distances, with kVCT the smallest. All of the established reconstruction methods exhibited similar abilities to detect the distances between BBs. The 3D CT-based methods, with lower axial resolution, showed more variation, particularly with the smaller BBs. With a software implementation, scout-based reconstruction is an appealing approach because it simplifies data acquisition over film-based reconstruction without requiring any specialized equipment

  2. Cranial computed tomography in infancy and childhood

    SciTech Connect

    Hammock, M.K.; Mihorat, T.H.

    1981-01-01

    A large number of pediatric cases have been accumulated and categorized according to congenital abnormalities, trauma, hydrocephalus, tumors, and infection. Each category contains background material accompanied by computed-tomographic (CT) illustrations and a related discussion. The material is derived from 6,000 CT scans performed at Children's Hospital National Medical Center in Washington, DC since 1973. (JMT)

  3. Computer tomography of large dust clouds in complex plasmas.

    PubMed

    Killer, Carsten; Himpel, Michael; Melzer, André

    2014-10-01

    The dust density is a central parameter of a dusty plasma. Here, a tomography setup for the determination of the three-dimensionally resolved density distribution of spatially extended dust clouds is presented. The dust clouds consist of micron-sized particles confined in a radio frequency argon plasma, where they fill almost the entire discharge volume. First, a line-of-sight integrated dust density is obtained from extinction measurements, where the incident light from an LED panel is scattered and absorbed by the dust. Performing these extinction measurements from many different angles allows the reconstruction of the 3D dust density distribution, analogous to a computer tomography in medical applications.

  4. Computer tomography of large dust clouds in complex plasmas

    SciTech Connect

    Killer, Carsten; Himpel, Michael; Melzer, André

    2014-10-15

    The dust density is a central parameter of a dusty plasma. Here, a tomography setup for the determination of the three-dimensionally resolved density distribution of spatially extended dust clouds is presented. The dust clouds consist of micron-sized particles confined in a radio frequency argon plasma, where they fill almost the entire discharge volume. First, a line-of-sight integrated dust density is obtained from extinction measurements, where the incident light from an LED panel is scattered and absorbed by the dust. Performing these extinction measurements from many different angles allows the reconstruction of the 3D dust density distribution, analogous to a computer tomography in medical applications.

  5. Assessment of asthmatic inflammation using hybrid fluorescence molecular tomography-x-ray computed tomography

    NASA Astrophysics Data System (ADS)

    Ma, Xiaopeng; Prakash, Jaya; Ruscitti, Francesca; Glasl, Sarah; Stellari, Fabio Franco; Villetti, Gino; Ntziachristos, Vasilis

    2016-01-01

    Nuclear imaging plays a critical role in asthma research but is limited in its readings of biology due to the short-lived signals of radio-isotopes. We employed hybrid fluorescence molecular tomography (FMT) and x-ray computed tomography (XCT) for the assessment of asthmatic inflammation based on resolving cathepsin activity and matrix metalloproteinase activity in dust mite, ragweed, and Aspergillus species-challenged mice. The reconstructed multimodal fluorescence distribution showed good correspondence with ex vivo cryosection images and histological images, confirming FMT-XCT as an interesting alternative for asthma research.

  6. [Positron emission tomography/computed tomography in follow-up programmes for patients with colorectal cancer].

    PubMed

    Hansen, Anne Fogh; Jensen, Mads Radmer; Nordholm-Carstensen, Andreas

    2016-09-12

    The current follow-up programmes for patients with colorectal cancer (CRC) after curative surgery do not include 18F-fluorodeoxyglucose-positron emission tomography (PET). Several small studies on selected patient populations indicate a high sensitivity of PET/computed tomography (CT) on visualizing relapse in patients with CRC after curative surgery. Therefore, PET/CT could probably be valuable in patients with unexplained increase in carcinoembryonic antigen level or a clinical suspicion of relapse, but PET/CT is not recommended as a standard in follow-up after CRC. PMID:27649583

  7. Change of Maximum Standardized Uptake Value Slope in Dynamic Triphasic [{sup 18}F]-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Distinguishes Malignancy From Postradiation Inflammation in Head-and-Neck Squamous Cell Carcinoma: A Prospective Trial

    SciTech Connect

    Anderson, Carryn M.; Chang, Tangel; Graham, Michael M.; Marquardt, Michael D.; Button, Anna; Smith, Brian J.; Menda, Yusuf; Sun, Wenqing; Pagedar, Nitin A.; Buatti, John M.

    2015-03-01

    Purpose: To evaluate dynamic [{sup 18}F]-fluorodeoxyglucose (FDG) uptake methodology as a post–radiation therapy (RT) response assessment tool, potentially enabling accurate tumor and therapy-related inflammation differentiation, improving the posttherapy value of FDG–positron emission tomography/computed tomography (FDG-PET/CT). Methods and Materials: We prospectively enrolled head-and-neck squamous cell carcinoma patients who completed RT, with scheduled 3-month post-RT FDG-PET/CT. Patients underwent our standard whole-body PET/CT scan at 90 minutes, with the addition of head-and-neck PET/CT scans at 60 and 120 minutes. Maximum standardized uptake values (SUV{sub max}) of regions of interest were measured at 60, 90, and 120 minutes. The SUV{sub max} slope between 60 and 120 minutes and change of SUV{sub max} slope before and after 90 minutes were calculated. Data were analyzed by primary site and nodal site disease status using the Cox regression model and Wilcoxon rank sum test. Outcomes were based on pathologic and clinical follow-up. Results: A total of 84 patients were enrolled, with 79 primary and 43 nodal evaluable sites. Twenty-eight sites were interpreted as positive or equivocal (18 primary, 8 nodal, 2 distant) on 3-month 90-minute FDG-PET/CT. Median follow-up was 13.3 months. All measured SUV endpoints predicted recurrence. Change of SUV{sub max} slope after 90 minutes more accurately identified nonrecurrence in positive or equivocal sites than our current standard of SUV{sub max} ≥2.5 (P=.02). Conclusions: The positive predictive value of post-RT FDG-PET/CT may significantly improve using novel second derivative analysis of dynamic triphasic FDG-PET/CT SUV{sub max} slope, accurately distinguishing tumor from inflammation on positive and equivocal scans.

  8. Computed tomography in acute cholecystitis: new observations

    SciTech Connect

    Kane, R.A.; Costello, P.; Duszlak, E.

    1983-10-01

    The computed tomographic CT findings in five patients with acute cholecystitis were analyzed. Common findings included thickening and nodularity of the gallbladder wall, cholelithiasis, and dilatation of the gallbladder lumen. Other more specific findings included poor definition of the gallbladder wall, pericholecystic fluid collections, and gas collections within the gallbladder wall. Most of the CT findings are suggestive but not pathognomonic, and correlation with the clinical, scintigraphic, and sonographic findings is necessary.

  9. High Speed Data Acquisition System for Three-Dimensional X-Ray and Neutron Computed Tomography

    SciTech Connect

    Davis, A.W.; Claytor, T.N.; Sheats, M.J.

    1999-07-01

    Computed tomography for nondestructive evaluation applications has been limited by system cost, resolution, and time requirements for three-dimensional data sets. FlashCT (Flat panel Amorphous Silicon High-Resolution Computed Tomography) is a system developed at Los Alamos National Laboratory to address these three problems. Developed around a flat panel amorphous silicon detector array, FlashCT is suitable for low to medium energy x-ray and neutron computed tomography at 127-micron resolution. Overall system size is small, allowing rapid transportation to a variety of radiographic sources. System control software was developed in LabVIEW for Windows NT to allow multithreading of data acquisition, data correction, and staging motor control. The system control software simplifies data collection and allows fully automated control of the data acquisition process, leading toward remote or unattended operation. The first generation of the FlashCT Data Acquisition System was completed in Au gust 1998, and since that time the system has been tested using x-ray sources ranging in energy from 60 kV to 20MV. The system has also been used to collect data for thermal neutron computed tomography at Los Alamos Neutron Science Center (LANSCE). System improvements have been proposed to provide faster data collection and greater dynamic range during data collection.

  10. 21 CFR 892.1750 - Computed tomography x-ray system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Computed tomography x-ray system. 892.1750 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1750 Computed tomography x-ray system. (a) Identification. A computed tomography x-ray system is a diagnostic x-ray system intended...

  11. 21 CFR 892.1750 - Computed tomography x-ray system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Computed tomography x-ray system. 892.1750 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1750 Computed tomography x-ray system. (a) Identification. A computed tomography x-ray system is a diagnostic x-ray system intended...

  12. 21 CFR 892.1750 - Computed tomography x-ray system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Computed tomography x-ray system. 892.1750 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1750 Computed tomography x-ray system. (a) Identification. A computed tomography x-ray system is a diagnostic x-ray system intended...

  13. 21 CFR 892.1750 - Computed tomography x-ray system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Computed tomography x-ray system. 892.1750 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1750 Computed tomography x-ray system. (a) Identification. A computed tomography x-ray system is a diagnostic x-ray system intended...

  14. 21 CFR 892.1750 - Computed tomography x-ray system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Computed tomography x-ray system. 892.1750 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1750 Computed tomography x-ray system. (a) Identification. A computed tomography x-ray system is a diagnostic x-ray system intended...

  15. Clinical utility of dental cone-beam computed tomography: current perspectives

    PubMed Central

    Jaju, Prashant P; Jaju, Sushma P

    2014-01-01

    Panoramic radiography and computed tomography were the pillars of maxillofacial diagnosis. With the advent of cone-beam computed tomography, dental practice has seen a paradigm shift. This review article highlights the potential applications of cone-beam computed tomography in the fields of dental implantology and forensic dentistry, and its limitations in maxillofacial diagnosis. PMID:24729729

  16. [Multispiral computed tomography in diagnosis of vascular pathology in patients with nonspecific aortoarteritis].

    PubMed

    Bakhritdinov, F Sh; Suiumov, A S

    2015-01-01

    Multispiral computed tomography in the angiographic mode is relatively a new method in diagnosis of arterial lesions in patients presenting with nonspecific aortoarteritis. With virtually no contraindications to carrying out the examination, this method makes it possible to obtain an exclusively clear-cut picture of the vascular bed in both two- and three-dimensional projection, to correlate it with osseous structures. This method of diagnosis may also be used for dynamic follow up of patients in the postoperative period. PMID:26673294

  17. Three-dimensional computed tomography from interferometric measurements within a narrow cone of views

    NASA Technical Reports Server (NTRS)

    Decker, Arthur J.; Izen, Steven H.

    1991-01-01

    A theory to determine the properties of a fluid from measurements of its projections was developed and tested. Viewing cones as small as 10 degrees were evaluated, with the only assumption being that the property was space limited. The results of applying the theory to numerical and actual interferograms of a spherical discontinuity of refractive index are presented. The theory was developed to test the practicality and limits of using three-dimensional computer tomography in internal fluid dynamics.

  18. X-ray computed tomography studies of gas storage and transport in Devonian shales

    SciTech Connect

    Lu, X.; Miao, P.; Watson, A.T. . Dept. of Chemical Engineering); Pepin, G.P.; Moss, R.M. ); Semmelbeck, M. )

    1994-07-01

    Devonian shales and other unconventional resources can be highly fractured and may have significant amounts of gas stored by adsorption. Conventional experiments are not well suited for characterizing the properties important for describing gas storage and transport in these media. Here, X-ray computed tomography scanning is used to determine gas storage in dynamic gas flow experiments on Devonian shale samples. Several important properties are obtained from these experiments, including fracture widths, adsorption isotherms, and matrix porosities and permeabilities.

  19. Computed tomography of human joints and radioactive waste drums

    SciTech Connect

    Ashby, E; Bernardi, R; Hollerbach, K; Logan, C; Martz, H; Roberson, G P

    1999-06-01

    X- and gamma-ray imaging techniques in nondestructive evaluation (NDE) and assay (NDA) have been increasing use in an array of industrial, environmental, military, and medical applications. Much of this growth in recent years is attributed to the rapid development of computed tomography (CT) and the use of NDE throughout the life-cycle of a product. Two diverse examples of CT are discussed. (1) The computational approach to normal joint kinematics and prosthetic joint analysis offers an opportunity to evaluate and improve prosthetic human joint replacements before they are manufactured or surgically implanted. Computed tomography data from scanned joints are segmented, resulting in the identification of bone and other tissues of interest, with emphasis on the articular surfaces. (2) They are developing NDE and NDE techniques to analyze closed waste drums accurately and quantitatively. Active and passive computed tomography (A and PCT) is a comprehensive and accurate gamma-ray NDA method that can identify all detectable radioisotopes present in a container and measure their radioactivity.

  20. Screening for lung cancer using low dose computed tomography.

    PubMed

    Tammemagi, Martin C; Lam, Stephen

    2014-01-01

    Screening for lung cancer with low dose computed tomography can reduce mortality from the disease by 20% in high risk smokers. This review covers the state of the art knowledge on several aspects of implementing a screening program. The most important are to identify people who are at high enough risk to warrant screening and the appropriate management of lung nodules found at screening. An accurate risk prediction model is more efficient than age and pack years of smoking alone at identifying those who will develop lung cancer and die from the disease. Algorithms are available for assessing people who screen positive to determine who needs additional imaging or invasive investigations. Concerns about low dose computed tomography screening include false positive results, overdiagnosis, radiation exposure, and costs. Further work is needed to define the frequency and duration of screening and to refine risk prediction models so that they can be used to assess the risk of lung cancer in special populations. Another important area is the use of computer vision software tools to facilitate high throughput interpretation of low dose computed tomography images so that costs can be reduced and the consistency of scan interpretation can be improved. Sufficient data are available to support the implementation of screening programs at the population level in stages that can be expanded when found to perform well to improve the outcome of patients with lung cancer. PMID:24865600

  1. Initial water quantification results using neutron computed tomography

    NASA Astrophysics Data System (ADS)

    Heller, A. K.; Shi, L.; Brenizer, J. S.; Mench, M. M.

    2009-06-01

    Neutron computed tomography is an important imaging tool in the field of non-destructive testing and in fundamental research for many engineering applications. Contrary to X-rays, neutrons can be attenuated by some light materials, such as hydrogen, but can penetrate many heavy materials. Thus, neutron computed tomography is useful in obtaining important three-dimensional information about a sample's interior structure and material properties that other traditional methods cannot provide. The neutron computed tomography system at the Pennsylvania State University's Radiation Science and Engineering Center is being utilized to develop a water quantification technique for investigation of water distribution in fuel cells under normal conditions. A hollow aluminum cylinder test sample filled with a known volume of water was constructed for purposes of testing the quantification technique. Transmission images of the test sample at different angles were easily acquired through the synthesis of a dedicated image acquisition computer driving a rotary table controller and an in-house developed synchronization software package. After data acquisition, Octopus (version 8.2) and VGStudio Max (version 1.2) were used to perform cross-sectional and three-dimensional reconstructions of the sample, respectively. The initial reconstructions and water quantification results are presented.

  2. Computed tomography of human joints and radioactive waste drums

    SciTech Connect

    Martz, Harry E.; Roberson, G. Patrick; Hollerbach, Karin; Logan, Clinton M.; Ashby, Elaine; Bernardi, Richard

    1999-12-02

    X- and gamma-ray imaging techniques in nondestructive evaluation (NDE) and assay (NDA) have seen increasing use in an array of industrial, environmental, military, and medical applications. Much of this growth in recent years is attributed to the rapid development of computed tomography (CT) and the use of NDE throughout the life-cycle of a product. Two diverse examples of CT are discussed, 1.) Our computational approach to normal joint kinematics and prosthetic joint analysis offers an opportunity to evaluate and improve prosthetic human joint replacements before they are manufactured or surgically implanted. Computed tomography data from scanned joints are segmented, resulting in the identification of bone and other tissues of interest, with emphasis on the articular surfaces. 2.) We are developing NDE and NDA techniques to analyze closed waste drums accurately and quantitatively. Active and passive computed tomography (A and PCT) is a comprehensive and accurate gamma-ray NDA method that can identify all detectable radioisotopes present in a container and measure their radioactivity.

  3. Spent nuclear fuel assembly inspection using neutron computed tomography

    NASA Astrophysics Data System (ADS)

    Pope, Chad Lee

    The research presented here focuses on spent nuclear fuel assembly inspection using neutron computed tomography. Experimental measurements involving neutron beam transmission through a spent nuclear fuel assembly serve as benchmark measurements for an MCNP simulation model. Comparison of measured results to simulation results shows good agreement. Generation of tomography images from MCNP tally results was accomplished using adapted versions of built in MATLAB algorithms. Multiple fuel assembly models were examined to provide a broad set of conclusions. Tomography images revealing assembly geometric information including the fuel element lattice structure and missing elements can be obtained using high energy neutrons. A projection difference technique was developed which reveals the substitution of unirradiated fuel elements for irradiated fuel elements, using high energy neutrons. More subtle material differences such as altering the burnup of individual elements can be identified with lower energy neutrons provided the scattered neutron contribution to the image is limited. The research results show that neutron computed tomography can be used to inspect spent nuclear fuel assemblies for the purpose of identifying anomalies such as missing elements or substituted elements. The ability to identify anomalies in spent fuel assemblies can be used to deter diversion of material by increasing the risk of early detection as well as improve reprocessing facility operations by confirming the spent fuel configuration is as expected or allowing segregation if anomalies are detected.

  4. Computational Fluid Dynamics For Helicopters

    NASA Technical Reports Server (NTRS)

    Caradonna, F. X.; Mccroskey, W. J.

    1990-01-01

    Powerful computer codes undergoing development. Report reviews development of computational fluid dynamics (CFD) for prediction of airflow around rotary wings of helicopters. Reviews progress in following endeavors: Prediction and verification of flows under various operating conditions; calculation of interactions between rotor blades and vortexes; analysis of viscous, transonic flows about airfoils; and study of formation of vortexes at tips of rotors.

  5. Computational aspects of multibody dynamics

    NASA Technical Reports Server (NTRS)

    Park, K. C.

    1989-01-01

    Computational aspects are addressed which impact the requirements for developing a next generation software system for flexible multibody dynamics simulation which include: criteria for selecting candidate formulation, pairing of formulations with appropriate solution procedures, need for concurrent algorithms to utilize computer hardware advances, and provisions for allowing open-ended yet modular analysis modules.

  6. Bimolecular dynamics by computer analysis

    SciTech Connect

    Eilbeck, J.C.; Lomdahl, P.S.; Scott, A.C.

    1984-01-01

    As numerical tools (computers and display equipment) become more powerful and the atomic structures of important biological molecules become known, the importance of detailed computation of nonequilibrium biomolecular dynamics increases. In this manuscript we report results from a well developed study of the hydrogen bonded polypeptide crystal acetanilide, a model protein. Directions for future research are suggested. 9 references, 6 figures.

  7. High contrast computed tomography with synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Itai, Yuji; Takeda, Tohoru; Akatsuka, Takao; Maeda, Tomokazu; Hyodo, Kazuyuki; Uchida, Akira; Yuasa, Tetsuya; Kazama, Masahiro; Wu, Jin; Ando, Masami

    1995-02-01

    This article describes a new monochromatic x-ray CT system using synchrotron radiation with applications in biomedical diagnosis which is currently under development. The system is designed to provide clear images and to detect contrast materials at low concentration for the quantitative functional evaluation of organs in correspondence with their anatomical structures. In this system, with x-ray energy changing from 30 to 52 keV, images can be obtained to detect various contrast materials (iodine, barium, and gadolinium), and K-edge energy subtraction is applied. Herein, the features of the new system designed to enhance the advantages of SR are reported. With the introduction of a double-crystal monochromator, the high-order x-ray contamination is eliminated. The newly designed CCD detector with a wide dynamic range of 60 000:1 has a spatial resolution of 200 μm. The resulting image quality, which is expected to show improved contrast and spatial resolution, is currently under investigation.

  8. Classification of breast computed tomography data

    SciTech Connect

    Nelson, Thomas R.; Cervino, Laura I.; Boone, John M.; Lindfors, Karen K.

    2008-03-15

    Differences in breast tissue composition are important determinants in assessing risk, identifying disease in images and following changes over time. This paper presents an algorithm for tissue classification that separates breast tissue into its three primary constituents of skin, fat and glandular tissue. We have designed and built a dedicated breast CT scanner. Fifty-five normal volunteers and patients with mammographically identified breast lesions were scanned. Breast CT voxel data were filtered using a 5 pt median filter and the image histogram was computed. A two compartment Gaussian fit of histogram data was used to provide an initial estimate of tissue compartments. After histogram analysis, data were input to region-growing algorithms and classified as to belonging to skin, fat or gland based on their value and architectural features. Once tissues were classified, a more detailed analysis of glandular tissue patterns and a more quantitative analysis of breast composition was made. Algorithm performance assessment demonstrated very good or excellent agreement between algorithm and radiologist observers in 97.7% of the segmented data. We observed that even in dense breasts the fraction of glandular tissue seldom exceeded 50%. For most individuals the composition is better characterized as being a 70% (fat)-30% (gland) composition than a 50% (fat)-50% (gland) composition.

  9. Computer animation challenges for computational fluid dynamics

    NASA Astrophysics Data System (ADS)

    Vines, Mauricio; Lee, Won-Sook; Mavriplis, Catherine

    2012-07-01

    Computer animation requirements differ from those of traditional computational fluid dynamics (CFD) investigations in that visual plausibility and rapid frame update rates trump physical accuracy. We present an overview of the main techniques for fluid simulation in computer animation, starting with Eulerian grid approaches, the Lattice Boltzmann method, Fourier transform techniques and Lagrangian particle introduction. Adaptive grid methods, precomputation of results for model reduction, parallelisation and computation on graphical processing units (GPUs) are reviewed in the context of accelerating simulation computations for animation. A survey of current specific approaches for the application of these techniques to the simulation of smoke, fire, water, bubbles, mixing, phase change and solid-fluid coupling is also included. Adding plausibility to results through particle introduction, turbulence detail and concentration on regions of interest by level set techniques has elevated the degree of accuracy and realism of recent animations. Basic approaches are described here. Techniques to control the simulation to produce a desired visual effect are also discussed. Finally, some references to rendering techniques and haptic applications are mentioned to provide the reader with a complete picture of the challenges of simulating fluids in computer animation.

  10. Bone single photon emission computed tomography with computed tomography disclosing chronic uterine perforation with intrauterine device migration into the anterior wall of the bladder: a case report

    PubMed Central

    2013-01-01

    Introduction Extraosseous uptake of 99mTc-hydroxymethylene diphosphonate is a common situation of variable clinical relevance. Case presentation A 52-year-old Caucasian woman presented to our department for breast cancer staging. A 99mTc-hydroxymethylene diphosphonate bone scan was performed and showed focal pelvic hyperfixation that disclosed intrauterine device migration into the anterior wall of the bladder on single photon emission computed tomography with computed tomography. Conclusion This observation confirms the major role of single photon emission computed tomography with computed tomography in achieving an exact diagnosis. PMID:23759143

  11. [Computed tomography in space-occupying intraspinal processes].

    PubMed

    Prömper, C; Friedmann, G

    1983-02-01

    Spinal computed tomography has considerably enhanced differential diagnostic safety in the course of the past two years. It has disclosed new possibilities of indication in the diagnosis of the vertebral column. With the expected improvement in apparatus technology, computed tomography will increasingly replace invasive examination methods. Detailed knowledge of clinical data, classification of the neurological findings, and localisation of the height--as far as possible--are the necessary prerequisites of successful diagnosis. If they are absent, it is recommended to perform myelography followed by secondary CT-myelography. If these preliminary conditions are observed, spinal CT can make outstanding contributions to the diagnosis of slipped disk, of the constricted vertebral canal, as well as tumours, malformations and posttraumatic conditions, postoperative changes and inflammatory processes. PMID:6338578

  12. Didactics and training in cardiovascular computed tomography angiography.

    PubMed

    Bhojraj, Sanjay D; Al-Mallah, Mouaz H

    2009-01-01

    As the role of cardiovascular computed tomography angiography (CCTA) is further expanded through research, the use of this technology will expand as a result of demand both from medical professionals and the public. To ensure a standardized quality of interpretation of these scans in the face of an increased demand for physicians qualified to interpret these studies, the Society of Cardiovascular Computed Tomography, along with several other professional societies, has proposed a didactic curriculum for the study of CCTA. This review highlights the currently proposed didactic curriculum for the study of CCTA, examines current trends in training for both medical trainees and physicians in practice, and proposes future directions for the study of CCTA. PMID:19203747

  13. Didactics and training in cardiovascular computed tomography angiography.

    PubMed

    Bhojraj, Sanjay D; Al-Mallah, Mouaz H

    2009-01-01

    As the role of cardiovascular computed tomography angiography (CCTA) is further expanded through research, the use of this technology will expand as a result of demand both from medical professionals and the public. To ensure a standardized quality of interpretation of these scans in the face of an increased demand for physicians qualified to interpret these studies, the Society of Cardiovascular Computed Tomography, along with several other professional societies, has proposed a didactic curriculum for the study of CCTA. This review highlights the currently proposed didactic curriculum for the study of CCTA, examines current trends in training for both medical trainees and physicians in practice, and proposes future directions for the study of CCTA.

  14. Analytic reconstruction approach for parallel translational computed tomography.

    PubMed

    Kong, Huihua; Yu, Hengyong

    2015-01-01

    To develop low-cost and low-dose computed tomography (CT) scanners for developing countries, recently a parallel translational computed tomography (PTCT) is proposed, and the source and detector are translated oppositely with respect to the imaging object without a slip-ring. In this paper, we develop an analytic filtered-backprojection (FBP)-type reconstruction algorithm for two dimensional (2D) fan-beam PTCT and extend it to three dimensional (3D) cone-beam geometry in a Feldkamp-type framework. Particularly, a weighting function is constructed to deal with data redundancy for multiple translations PTCT to eliminate image artifacts. Extensive numerical simulations are performed to validate and evaluate the proposed analytic reconstruction algorithms, and the results confirm their correctness and merits. PMID:25882732

  15. Single photon emission computed tomography in seizure disorders.

    PubMed Central

    Denays, R; Rubinstein, M; Ham, H; Piepsz, A; Noël, P

    1988-01-01

    Fourteen children with various seizure disorders were studied using a cerebral blood flow tracer, 123I iodoamphetamine (0.05 mCi/kg), and single photon emission computed tomography (SPECT). In the five patients with radiological lesions, SPECT showed congruent or more extensive abnormalities. Five of the nine children with a normal scan on computed tomography had abnormal SPECT studies consisting of focal hypoperfusion, diffuse hemispheric hypoperfusion, multifocal and bilateral hypoperfusion, or focal hyperperfusion. A focal lesion seen on SPECT has been found in children with tonic-clonic seizures suggesting secondarily generalised seizures. Moreover the pattern seen on SPECT seemed to be related to the clinical status. An extensive impairment found on SPECT was associated with a poor evolution in terms of intellectual performance and seizure frequency. Conversely all children with a normal result on SPECT had less than two seizures per year and normal neurological and intellectual development. Images Figure PMID:3264135

  16. [Potentialities of computed tomography in the diagnosis of hiatal hernia].

    PubMed

    Gorshkov, A N

    2003-01-01

    An analysis of the results of 98 studies has demonstrated the potentialities of X-ray computed tomography in the diagnosis of hiatal hernia (HH), provided the X-ray computed tomography (XCT) semiotics of HH. It has found that XCT may directly visualize and objectively evaluate anatomic structures, such as diagraphmatic crus and esophageal foremen. It has emphasized that when XCT of abdominal and thoracic organs is performed, it is necessary to include the areas of diagragmatic curs and esophageal foramen into the list of anatomic structures binding for visual assessment and characterization, which in combination with other studies will assist in the early diagnosis of hiatal hernia and eventually expand the potentialities of XCT to a greater extent.

  17. Computational Workbench for Multibody Dynamics

    NASA Technical Reports Server (NTRS)

    Edmonds, Karina

    2007-01-01

    PyCraft is a computer program that provides an interactive, workbenchlike computing environment for developing and testing algorithms for multibody dynamics. Examples of multibody dynamic systems amenable to analysis with the help of PyCraft include land vehicles, spacecraft, robots, and molecular models. PyCraft is based on the Spatial-Operator- Algebra (SOA) formulation for multibody dynamics. The SOA operators enable construction of simple and compact representations of complex multibody dynamical equations. Within the Py-Craft computational workbench, users can, essentially, use the high-level SOA operator notation to represent the variety of dynamical quantities and algorithms and to perform computations interactively. PyCraft provides a Python-language interface to underlying C++ code. Working with SOA concepts, a user can create and manipulate Python-level operator classes in order to implement and evaluate new dynamical quantities and algorithms. During use of PyCraft, virtually all SOA-based algorithms are available for computational experiments.

  18. Computed Tomography Inspection and Analysis for Additive Manufacturing Components

    NASA Technical Reports Server (NTRS)

    Beshears, Ronald D.

    2016-01-01

    Computed tomography (CT) inspection was performed on test articles additively manufactured from metallic materials. Metallic AM and machined wrought alloy test articles with programmed flaws were inspected using a 2MeV linear accelerator based CT system. Performance of CT inspection on identically configured wrought and AM components and programmed flaws was assessed using standard image analysis techniques to determine the impact of additive manufacturing on inspectability of objects with complex geometries.

  19. Micro Computer Tomography for medical device and pharmaceutical packaging analysis.

    PubMed

    Hindelang, Florine; Zurbach, Raphael; Roggo, Yves

    2015-04-10

    Biomedical device and medicine product manufacturing are long processes facing global competition. As technology evolves with time, the level of quality, safety and reliability increases simultaneously. Micro Computer Tomography (Micro CT) is a tool allowing a deep investigation of products: it can contribute to quality improvement. This article presents the numerous applications of Micro CT for medical device and pharmaceutical packaging analysis. The samples investigated confirmed CT suitability for verification of integrity, measurements and defect detections in a non-destructive manner.

  20. [Efficiency of computed tomography in diagnosis of silicotuberculosis].

    PubMed

    Naumenko, E S; Gol'del'man, A G; Tikhotskaia, L I; Zhovtiak, E P; Iarina, A L; Ershov, V I; Larina, E N

    1998-01-01

    The routine methods X-ray study and computed tomography (CT) were compared in a group of patients engaged in fireproof industry. CT yields valuable additional data in early silicotuberculosis, which makes it possible to follow the extent of a silicotuberculous process more completely, to make a better diagnosis of nodal and focal shadows, to identify small decay cavities in the foci and infiltrates. CT is the method of choice in following up patients with silicotuberculosis.

  1. Use of Cone Beam Computed Tomography in Endodontics

    PubMed Central

    Scarfe, William C.; Levin, Martin D.; Gane, David; Farman, Allan G.

    2009-01-01

    Cone Beam Computed Tomography (CBCT) is a diagnostic imaging modality that provides high-quality, accurate three-dimensional (3D) representations of the osseous elements of the maxillofacial skeleton. CBCT systems are available that provide small field of view images at low dose with sufficient spatial resolution for applications in endodontic diagnosis, treatment guidance, and posttreatment evaluation. This article provides a literature review and pictorial demonstration of CBCT as an imaging adjunct for endodontics. PMID:20379362

  2. Computed tomography identification of an exophytic colonic liposarcoma.

    PubMed

    Chou, Chung Kuao; Chen, Sung-Ting

    2016-09-01

    It may be difficult to ascertain the relationship between a large intra-abdominal tumor and the adjacent organs if they are close together. In the current case, a definitive preoperative diagnosis of an exophytic colonic tumor was obtained by the demonstration of obtuse angles between the tumor and colon and by distinct recognition of the mucosa-submucosa of the colonic wall on computed tomography; the accuracy of this preoperative diagnosis was subsequently confirmed by pathologic findings. PMID:27594941

  3. A comparison between abdominal ultrasonography and computed tomography.

    PubMed

    Becker, H; Pienaar, G J

    1980-06-28

    Computed tomography (CT) and ultrasonography are based on entirely different physical principles. In the abdomen the two techniques have similar diagnostic applications. Whereas CT is in many instances more informative, it is also a more time-consuming and much more costly procedure. For clinicians who practise in areas where these techniques are available, this article may be useful as a quick guide to the choice of procedure.

  4. Ureterolithiasis: classical and atypical findings on unenhanced helical computed tomography.

    PubMed

    Vaswani, Kuldeep K; El-Dieb, Adam; Vitellas, Kenneth M; Bennett, William F; Bova, James G

    2002-03-01

    Evaluation of patients with acute flank pain using helical computed tomography (CT) is a well-accepted, rapid, and safe procedure in the emergency setting. Various primary and secondary signs are described in the literature for evaluation of these patients. Our purpose is to demonstrate both the classical findings associated with ureteral calculi on unenhanced helical CT and atypical findings and potential pitfalls. We also provide readers with a systematic approach to interpreting unenhanced helical CT scans performed for acute flank pain.

  5. [Multislice spiral computed tomography in the diagnosis of osteomyelitis].

    PubMed

    Egorova, E A; Zorina, I S; Sangaeva, L M

    2010-01-01

    This paper deals with the results of a radiation study in 34 patients with the clinical manifestations of maxillofacial osteomyelitides. It describes the radiation semiotics of changes occurring in the bone and its surrounding soft tissues of the maxillofacial region in different phases of osteomyelitis. Comparative analysis of orthopantograms and images obtained by multislice spiral computed tomography revealed the benefits of the latter in detecting soft tissue changes and subtle bone alterations.

  6. Comparison of computed tomography and pluridirectional tomography of the temporal bone

    SciTech Connect

    Lufkin, R.; Barni, J.J.; Glen, W.; Mancuso, A.; Canalis, R.; Hanafee, W.

    1982-06-01

    During pluridirectional tomography dense bone creates ghost shadows that simulate chronic disease and soft-tissue masses within the middle ear cavity. This effect was demonstrated in three dried skulls. Cholesteatomas were simulated in three more temporal bones with a mixture of 2% iodine in paraffin. Three different high-resolution computed tomographic scanners clearly demonstrated middle ear anatomy and the simulated soft-tissue masses in the skulls.

  7. SADMFR guidelines for the use of Cone-Beam Computed Tomography/ Digital Volume Tomography.

    PubMed

    Dula, Karl; Bornstein, Michael M; Buser, Daniel; Dagassan-Berndt, Dorothea; Ettlin, Dominik A; Filippi, Andreas; Gabioud, François; Katsaros, Christos; Krastl, Gabriel; Lambrecht, J Thomas; Lauber, Roland; Luebbers, Heinz-Theo; Pazera, Pawel; Türp, Jens C

    2014-01-01

    Cone-Beam Computed Tomography (CBCT) has been introduced in 1998. This radiological imaging procedure has been provided for dentistry and is comparable to computed tomography (CT) in medicine. It is expected that CBCT will have the same success in dental diagnostic imaging as computed tomography had in medicine. Just as CT is responsible for a significant rise in radiation dose to the population from medical X-ray diagnostics, CBCT studies will be accompanied by a significant increase of the dose to our patients by dentistry. Because of the growing concern for an uncritical and consequently rapidly increasing use of CBCT the Swiss Society of Dentomaxillofacial Radiology convened a first consensus conference in 2011 to formulate indications for CBCT, which can be used as guidelines. In this meeting, oral and maxillofacial surgery, orthodontics and temporomandibular joint disorders and diseases were treated and the most important and most experienced users of DVT in these areas were asked to participate. In general, a highly restrictive use of CBCT is required. Justifying main criterion for CBCT application is that additional, therapy-relevant information is expected that should lead to a significant benefit in patient care. All users of CBCT should have completed a structured, high-level training, just like that offered by the Swiss Society of Dentomaxillofacial Radiology.

  8. Validation of visual surface measurement using computed tomography

    NASA Astrophysics Data System (ADS)

    VanBerlo, Amy M.; Campbell, Aaron R.; Ellis, Randy E.

    2011-03-01

    Although dysesthesia is a common and persistent surgical complication, there is no accepted method for quantitatively tracking affected skin. To address this, two types of computer vision technologies were tested in a total of four configurations. Surface regions on plastic models of limbs were delineated with colored tape, imaged, and compared with computed tomography scans. The most accurate system used visually projected texture captured by a binocular stereo camera, capable of measuring areas to within 0.05% of the ground-truth areas with 1.4% variance. This simple, inexpensive technology shows promise for postoperative monitoring of dysesthesia surrounding surgical scars.

  9. [Role of cone-beam computed tomography in diagnostic otorhinolaryngological imaging].

    PubMed

    Perényi, Ádám; Bella, Zsolt; Baráth, Zoltán; Magyar, Péter; Nagy, Katalin; Rovó, László

    2016-01-10

    Accurate diagnosis and preoperative planning in modern otorhinolaryngology is strongly supported by imaging with enhanced visualization. Computed tomography is often used to examine structures within bone frameworks. Given the hazards of ionizing radiation, repetitive imaging studies exponentially increase the risk of damages to radiosensitive tissues. The authors compare multislice and cone-beam computed tomography and determine the role, advantages and disadvantages of cone-beam computed tomography in otorhinolaryngological imaging. They summarize the knowledge from the international literature and their individual imaging studies. They conclude that cone-beam computed tomography enables high-resolution imaging and reconstruction in any optional plane and in space with considerably lower effective radiation dose. Cone-beam computed tomography with appropriate indications proved to be an excellent diagnostic tool in otorhinolaryngological imaging. It makes an alternative to multislice computed tomography and it is an effective tool in perioperative and postoperative follow-up, especially in those cases which necessitate repetitive imaging with computed tomography.

  10. Parallel multithread computing for spectroscopic analysis in optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Trojanowski, Michal; Kraszewski, Maciej; Strakowski, Marcin; Pluciński, Jerzy

    2014-05-01

    Spectroscopic Optical Coherence Tomography (SOCT) is an extension of Optical Coherence Tomography (OCT). It allows gathering spectroscopic information from individual scattering points inside the sample. It is based on time-frequency analysis of interferometric signals. Such analysis requires calculating hundreds of Fourier transforms while performing a single A-scan. Additionally, further processing of acquired spectroscopic information is needed. This significantly increases the time of required computations. During last years, application of graphical processing units (GPU's) was proposed to reduce computation time in OCT by using parallel computing algorithms. GPU technology can be also used to speed-up signal processing in SOCT. However, parallel algorithms used in classical OCT need to be revised because of different character of analyzed data. The classical OCT requires processing of long, independent interferometric signals for obtaining subsequent A-scans. The difference with SOCT is that it requires processing of multiple, shorter signals, which differ only in a small part of samples. We have developed new algorithms for parallel signal processing for usage in SOCT, implemented with NVIDIA CUDA (Compute Unified Device Architecture). We present details of the algorithms and performance tests for analyzing data from in-house SD-OCT system. We also give a brief discussion about usefulness of developed algorithm. Presented algorithms might be useful for researchers working on OCT, as they allow to reduce computation time and are step toward real-time signal processing of SOCT data.

  11. Joint modeling of lithosphere and mantle dynamics: Evaluation of constraints from global tomography models

    NASA Astrophysics Data System (ADS)

    Wang, Xinguo; Holt, William E.; Ghosh, Attreyee

    2015-12-01

    With the advances in technology, seismological theory, and data acquisition, a number of high-resolution seismic tomography models have been published. However, discrepancies between tomography models often arise from different theoretical treatments of seismic wave propagation, different inversion strategies, and different data sets. Using a fixed velocity-to-density scaling and a fixed radial viscosity profile, we compute global mantle flow models associated with the different tomography models and test the impact of these for explaining surface geophysical observations (geoid, dynamic topography, stress, and strain rates). We use the joint modeling of lithosphere and mantle dynamics approach of Ghosh and Holt (2012) to compute the full lithosphere stresses, except that we use HC for the mantle circulation model, which accounts for the primary flow-coupling features associated with density-driven mantle flow. Our results show that the seismic tomography models of S40RTS and SAW642AN provide a better match with surface observables on a global scale than other models tested. Both of these tomography models have important similarities, including upwellings located in Pacific, Eastern Africa, Iceland, and mid-ocean ridges in the Atlantic and Indian Ocean and downwelling flows mainly located beneath the Andes, the Middle East, and central and Southeast Asia.

  12. Compensator models for fluence field modulated computed tomography

    SciTech Connect

    Bartolac, Steven; Jaffray, David

    2013-12-15

    Purpose: Fluence field modulated computed tomography (FFMCT) presents a novel approach for acquiring CT images, whereby a patient model guides dynamically changing fluence patterns in an attempt to achieve task-based, user-prescribed, regional variations in image quality, while also controlling dose to the patient. This work aims to compare the relative effectiveness of FFMCT applied to different thoracic imaging tasks (routine diagnostic CT, lung cancer screening, and cardiac CT) when the modulator is subject to limiting constraints, such as might be present in realistic implementations.Methods: An image quality plan was defined for a simulated anthropomorphic chest slice, including regions of high and low image quality, for each of the thoracic imaging tasks. Modulated fluence patterns were generated using a simulated annealing optimization script, which attempts to achieve the image quality plan under a global dosimetric constraint. Optimization was repeated under different types of modulation constraints (e.g., fixed or gantry angle dependent patterns, continuous or comprised of discrete apertures) with the most limiting case being a fixed conventional bowtie filter. For each thoracic imaging task, an image quality map (IQM{sub sd}) representing the regionally varying standard deviation is predicted for each modulation method and compared to the prescribed image quality plan as well as against results from uniform fluence fields. Relative integral dose measures were also compared.Results: Each IQM{sub sd} resulting from FFMCT showed improved agreement with planned objectives compared to those from uniform fluence fields for all cases. Dynamically changing modulation patterns yielded better uniformity, improved image quality, and lower dose compared to fixed filter patterns with optimized tube current. For the latter fixed filter cases, the optimal choice of tube current modulation was found to depend heavily on the task. Average integral dose reduction compared

  13. Computed tomography and (18)F-fluorodeoxyglucose positron emission tomography/computed tomography findings in adrenal candidiasis and histoplasmosis: two cases.

    PubMed

    Altinmakas, Emre; Guo, Ming; Kundu, Uma R; Habra, Mouhammed Amir; Ng, Chaan

    2015-01-01

    We report the contrast-enhanced computed tomography (CT) and (18)F-fluorodeoxyglucose positron emission tomography findings in adrenal histoplasmosis and candidiasis. Both demonstrated bilateral hypermetabolic heterogeneous adrenal masses with limited wash-out on delayed CT. Adrenal candidiasis has not been previously reported, nor have the CT wash-out findings in either infection. The adrenal imaging findings are indistinguishable from malignancy, which is more common; but in this setting, physicians should be alert to the differential diagnosis of fungal infections, since it can be equally deadly.

  14. Diffraction computed tomography reveals the inner structure of complex biominerals

    NASA Astrophysics Data System (ADS)

    Leemreize, Hanna; Birkbak, Mie; Frølich, Simon; Kenesei, Peter; Almer, Jonathan D.; Stock, Stuart R.; Birkedal, Henrik

    2014-09-01

    Biological materials are complex and their investigation demands advanced characterization tools capable of elucidating their structure in three dimensions without the need for complicated sample preparation. Herein, we discuss our implementation of diffraction/scattering computed tomography (DSCT). DSCT is based on the use of diffraction information for tomographic reconstructions rather than linear attenuation as in regular μ-CT. This provides much additional information on the material under investigation. We illustrate the use of DSCT by discussion of data on a biomineralized attachment organ from a marine mussel. DSCT allowed mapping the spatial distribution of calcium carbonate polymorphs aragonite and calcite even though they were indistinguishable in absorption tomography. Detailed analysis of reconstructed diffraction patterns may provide additional insights as exemplified in the present case by mapping of the degree of chemical substitution in calcite.

  15. Single photon emission computed tomography in AIDS dementia complex

    SciTech Connect

    Pohl, P.; Vogl, G.; Fill, H.; Roessler, H.Z.; Zangerle, R.; Gerstenbrand, F.

    1988-08-01

    Single photon emission computed tomography (SPECT) studies were performed in AIDS dementia complex using IMP in 12 patients (and HM-PAO in four of these same patients). In all patients, SPECT revealed either multiple or focal uptake defects, the latter corresponding with focal signs or symptoms in all but one case. Computerized tomography showed a diffuse cerebral atrophy in eight of 12 patients, magnetic resonance imaging exhibited changes like atrophy and/or leukoencephalopathy in two of five cases. Our data indicate that both disturbance of cerebral amine metabolism and alteration of local perfusion share in the pathogenesis of AIDS dementia complex. SPECT is an important aid in the diagnosis of AIDS dementia complex and contributes to the understanding of the pathophysiological mechanisms of this disorder.

  16. Imaging local brain function with emission computed tomography

    SciTech Connect

    Kuhl, D.E.

    1984-03-01

    Positron emission tomography (PET) using /sup 18/F-fluorodeoxyglucose (FDG) was used to map local cerebral glucose utilization in the study of local cerebral function. This information differs fundamentally from structural assessment by means of computed tomography (CT). In normal human volunteers, the FDG scan was used to determine the cerebral metabolic response to conrolled sensory stimulation and the effects of aging. Cerebral metabolic patterns are distinctive among depressed and demented elderly patients. The FDG scan appears normal in the depressed patient, studded with multiple metabolic defects in patients with multiple infarct dementia, and in the patients with Alzheimer disease, metabolism is particularly reduced in the parietal cortex, but only slightly reduced in the caudate and thalamus. The interictal FDG scan effectively detects hypometabolic brain zones that are sites of onset for seizures in patients with partial epilepsy, even though these zones usually appear normal on CT scans. The future prospects of PET are discussed.

  17. [The importance of computed tomography and magnetic resonance tomography in shockwave cholelithotripsy].

    PubMed

    Golder, W A; Tempel, U; Gmeinwieser, J

    1989-01-01

    With shockwave-lithotripsy a new method of therapy has been introduced, whose efficiency is essentially determined by that of the accompanying imaging diagnostics. This poses several new problems for the diagnostic radiologist. While sonography and conventional cholegraphy have an important place in connection with shockwave-lithotripsy, the role of computed tomography (CT) and magnetic resonance tomography (MRT) has not yet been established. According to our experiences and experimental data pre-interventional CT improves the accuracy for measurements of the calcium content of concrements and gives the best survey on the topography of the upper abdomen of patients with biliary concrements. MRT before lithotripsy does not yield important additional information. Applied after intervention it at least equals CT. Besides localization and description of the diseased gall-bladder the detection of complications with CT and MRT is one of the tasks of the radiologist in connection with shockwave-lithotripsy.

  18. Extramedullary Plasmacytoma of the Gallbladder Detected on Fluorine 18-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

    PubMed Central

    Fakhri, Asif Ali; Rodrigue, Paul David; Fakhri, Amena Fatima

    2016-01-01

    Extramedullary plasmacytoma is rare in patients with diagnosed multiple myeloma. Soft tissue plasmacytoma of the gallbladder is particularly uncommon and has been described in only a handful of cases. Diagnosis of gallbladder plasmacytoma with fluorine 18-fluorodeoxyglucose (F18-FDG) positron emission tomography/computed tomography (PET/CT) has not previously been reported. We present a 65-year-old female with a history of multiple myeloma who underwent a restaging F18-FDG-PET/CT which showed a focal area of hypermetabolic activity, corresponding to a nodular lesion within the posterior gallbladder wall. The patient underwent successful cholecystectomy, with surgical pathology revealing gallbladder plasmacytoma. A follow-up scan was negative for active malignancy. This is a novel case of gallbladder plasmacytoma diagnosed on whole-body F18-FDG PET/CT – thus demonstrating the clinical value of this imaging modality in staging, restaging, and surveillance for patients with multiple myeloma. PMID:27761300

  19. Unusual case of infantile fibrosarcoma evaluated on F-18 fluorodeoxyglucose positron emission tomography-computed tomography

    PubMed Central

    Bedmutha, Akshay; Singh, Natasha; Shivdasani, Divya; Gupta, Nitin

    2016-01-01

    Infantile fibrosarcoma (IFS) is a rare soft-tissue sarcoma originating from extremities and occasionally from axial soft tissue. The prognosis is good with favorable long-term survival. It is rarely metastasizing tumor, the chances being lesser with IFS originating from extremities. Use of neoadjuvant chemotherapy (NACT) as a treatment regime further reduces the chances of local relapse and distant metastasis. The organs commonly affected in metastatic IFS are lungs and lymph nodes. We report an unusual case of an IFS originating from extremity, which received NACT, yet presented with an early metastatic disease involving soft tissues and sparing lungs and lymph nodes, as demonstrated on fluorodeoxyglucose positron emission tomography-computed tomography. PMID:27385891

  20. A case of sarcoidosis diagnosed by positron emission tomography/computed tomography

    PubMed Central

    Aksoy, Sabire Yilmaz; Özdemir, Elif; Sentürk, Aysegül; Türkölmez, Seyda

    2016-01-01

    Sarcoidosis is a multisystem granulomatous disorder of unknown cause which may affect any organ or system but primarily involve the lungs and the lymphatic system. Extrapulmonary sarcoidosis represents approximately 30-50% of patients. We report the case of a 51-year-old female who presented with increasing complaints of a cough, weakness, weight loss, and chest pain and who was found to have a suspicious lesion on thorax computed tomography(CT). Fluorodeoxyglucose (FDG) positron emission tomography/CT performed for diagnostic purposes demonstrated increased FDG accumulation at the bilateral enlarged parotid and lacrimal gland and in the reticulonodular infiltration area located in the left lung as well as multiple lymphadenopathies with increased FDG accumulation. There were also hepatosplenomegaly and splenic uptake. Skin biopsy showed noncaseating granulomas, and the patient was diagnosed as stage 2 sarcoidosis. PMID:27385890

  1. Quantitative cone beam X-ray luminescence tomography/X-ray computed tomography imaging

    SciTech Connect

    Chen, Dongmei; Zhu, Shouping Chen, Xueli; Chao, Tiantian; Cao, Xu; Zhao, Fengjun; Huang, Liyu; Liang, Jimin

    2014-11-10

    X-ray luminescence tomography (XLT) is an imaging technology based on X-ray-excitable materials. The main purpose of this paper is to obtain quantitative luminescence concentration using the structural information of the X-ray computed tomography (XCT) in the hybrid cone beam XLT/XCT system. A multi-wavelength luminescence cone beam XLT method with the structural a priori information is presented to relieve the severe ill-posedness problem in the cone beam XLT. The nanophosphors and phantom experiments were undertaken to access the linear relationship of the system response. Then, an in vivo mouse experiment was conducted. The in vivo experimental results show that the recovered concentration error as low as 6.67% with the location error of 0.85 mm can be achieved. The results demonstrate that the proposed method can accurately recover the nanophosphor inclusion and realize the quantitative imaging.

  2. Combined positron emission tomography and computed tomography to visualize and quantify fluid flow in sedimentary rocks

    NASA Astrophysics Data System (ADS)

    Fernø, M. A.; Gauteplass, J.; Hauge, L. P.; Abell, G. E.; Adamsen, T. C. H.; Graue, A.

    2015-09-01

    Here we show for the first time the combined positron emission tomography (PET) and computed tomography (CT) imaging of flow processes within porous rocks to quantify the development in local fluid saturations. The coupling between local rock structure and displacement fronts is demonstrated in exploratory experiments using this novel approach. We also compare quantification of 3-D temporal and spatial water saturations in two similar CO2 storage tests in sandstone imaged separately with PET and CT. The applicability of each visualization technique is evaluated for a range of displacement processes, and the favorable implementation of combining PET/CT for laboratory core analysis is discussed. We learn that the signal-to-noise ratio (SNR) is over an order of magnitude higher for PET compared with CT for the studied processes.

  3. A case of sarcoidosis diagnosed by positron emission tomography/computed tomography.

    PubMed

    Aksoy, Sabire Yilmaz; Özdemir, Elif; Sentürk, Aysegül; Türkölmez, Seyda

    2016-01-01

    Sarcoidosis is a multisystem granulomatous disorder of unknown cause which may affect any organ or system but primarily involve the lungs and the lymphatic system. Extrapulmonary sarcoidosis represents approximately 30-50% of patients. We report the case of a 51-year-old female who presented with increasing complaints of a cough, weakness, weight loss, and chest pain and who was found to have a suspicious lesion on thorax computed tomography(CT). Fluorodeoxyglucose (FDG) positron emission tomography/CT performed for diagnostic purposes demonstrated increased FDG accumulation at the bilateral enlarged parotid and lacrimal gland and in the reticulonodular infiltration area located in the left lung as well as multiple lymphadenopathies with increased FDG accumulation. There were also hepatosplenomegaly and splenic uptake. Skin biopsy showed noncaseating granulomas, and the patient was diagnosed as stage 2 sarcoidosis. PMID:27385890

  4. Multi-GPU Jacobian Accelerated Computing for Soft Field Tomography

    PubMed Central

    Borsic, A.; Attardo, E. A.; Halter, R. J.

    2012-01-01

    Image reconstruction in soft-field tomography is based on an inverse problem formulation, where a forward model is fitted to the data. In medical applications, where the anatomy presents complex shapes, it is common to use Finite Element Models to represent the volume of interest and to solve a partial differential equation that models the physics of the system. Over the last decade, there has been a shifting interest from 2D modeling to 3D modeling, as the underlying physics of most problems are three-dimensional. Though the increased computational power of modern computers allows working with much larger FEM models, the computational time required to reconstruct 3D images on a fine 3D FEM model can be significant, on the order of hours. For example, in Electrical Impedance Tomography applications using a dense 3D FEM mesh with half a million elements, a single reconstruction iteration takes approximately 15 to 20 minutes with optimized routines running on a modern multi-core PC. It is desirable to accelerate image reconstruction to enable researchers to more easily and rapidly explore data and reconstruction parameters. Further, providing high-speed reconstructions are essential for some promising clinical application of EIT. For 3D problems 70% of the computing time is spent building the Jacobian matrix, and 25% of the time in forward solving. In the present work, we focus on accelerating the Jacobian computation by using single and multiple GPUs. First, we discuss an optimized implementation on a modern multi-core PC architecture and show how computing time is bounded by the CPU-to-memory bandwidth; this factor limits the rate at which data can be fetched by the CPU. Gains associated with use of multiple CPU cores are minimal, since data operands cannot be fetched fast enough to saturate the processing power of even a single CPU core. GPUs have a much faster memory bandwidths compared to CPUs and better parallelism. We are able to obtain acceleration factors of

  5. Reconstruction of limited computed tomography data of fuel cell components using Direct Iterative Reconstruction of Computed Tomography Trajectories

    NASA Astrophysics Data System (ADS)

    Lange, Axel; Kupsch, Andreas; Hentschel, Manfred P.; Manke, Ingo; Kardjilov, Nikolay; Arlt, Tobias; Grothausmann, Roman

    CT (computed tomography) reconstructions of fuel cell components of a yet unrivaled spatial resolution and quality are presented. This is achieved by application of the novel DIRECTT (Direct Iterative Reconstruction of Computed Tomography Trajectories) algorithm. We focus on two different key issues which essentially rule the fuel cell's durability on different length scales and physical interactions. On the resolution scale of some 100 μm agglomerations of condensed water in flow-field channels are detected by means of quasi- in situ neutron CT (after operation). Five orders of magnitude below nanometer sized Ru catalyst particles on carbon black support are visualized by electron tomography. Both types of experiments are especially adapted to the type of material involved but they are accompanied by severe deviations from ideal CT measuring conditions, as well. In order to overcome the tremendous reconstruction artifacts of standard algorithms, we employ DIRECTT which is described in detail. Comparisons of DIRECTT reconstructions to the conventional filtered back projection, prove the significant improvements in both experimental methods.

  6. Detection of lung cancer in patients with pneumoconiosis by fluorodeoxyglucose-positron emission tomography/computed tomography: four cases.

    PubMed

    Yu, Hua; Zhang, Hua; Wang, Yanli; Cui, Xinjian; Han, Jiankui

    2013-01-01

    We report 4 cases of lung cancer in patients with pneumoconiosis detected by F18-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT), which could differentiate lung cancer and pneumoconiosis. FDG-PET/CT may be useful in cancer screening for patients with pneumoconiosis.

  7. Clinical efficacy of 2-phase versus 4-phase computed tomography for localization in primary hyperparathyroidism

    PubMed Central

    Ramirez, Adriana G.; Shada, Amber L.; Martin, Allison N.; Raghavan, Prashant; Durst, Christopher R.; Mukherjee, Sugoto; Gaughen, John R.; Ornan, David A.; Hanks, John B.; Smith, Philip W.

    2016-01-01

    Background Four-dimensional computed tomography is being used increasingly for localization of abnormal glands in primary hyperparathyroidism. We hypothesized that compared with traditional 4-phase imaging, 2-phase imaging would halve the radiation dose without compromising parathyroid localization and clinical outcomes. Methods A transition from 4-phase to 2-phase imaging was instituted between 2009 and 2010. A pre-post analysis was performed on patients undergoing operative treatment with a parathyroid protocol computed tomography, and relevant data were correlated with operative findings. Sensitivity, positive predictive value, technical success, and cure rates were calculated. The Fisher exact test or χ2 test assessed the significance of 2-phase and 4-phase imaging and operative findings. Results Twenty-seven patients had traditional four-dimensional computed tomography and 35 had modified 2-phase computed tomography. Effective radiation doses were 6.8 mSy for 2-phase and 14 mSv for 4-phase. Four-phase computed tomography had a sensitivity and positive predictive value of 93% and 96%, respectively. Two-phase computed tomography had a comparable sensitivity and positive predictive value of 97% and 94%, respectively. Eight patients with discordant imaging had an average parathyroid weight of 240 g compared with 1,300 g for all patients. Technical surgical success (90% for 4-phase computed tomography versus 91% 2-phase computed tomography) and normocalcemia rates at 6 months (88% for both) did not differ between computed tomography protocols. Computed tomography correctly predicted multiglandular disease and localization for reoperations in 88% and 90% of cases, respectively, with no difference by computed tomography protocol. Conclusion With regard to surgical outcomes and localization, 2-phase parathyroid computed tomography is equivalent to 4-phase for parathyroid localization, including small adenomas, reoperative cases, and multiglandular disease. Two

  8. Renal trauma: radiological studies - comparison of urography, computed tomography, angiography, and radionuclide studies

    SciTech Connect

    Lang, E.K.; Sullivan, J.; Frentz, G.

    1985-01-01

    Excretory urography, computed radionuclide urography, angiography, and both conventional and dynamic computed tomography (CT) were compared with regard to accuracy, sensitivity, and specificity in 388 patients with renal trauma. Used as the triage examination, urography established the absence of significant renal injury with an accuracy of 87%, obviating further evaluation. Dynamic CT proved to be the best methods of assessing parenchymal injuries, establishing the correct diagnosis in 129 out of 130 cases compared to 116/130 for conventional CT. Angiography was the procedure of choice for diagnosis and categorization of renal artery injuries, which were diagnosed correctly in all 43 cases. The choice between dynamic CT and angiography as the second examination rests upon careful evaluation of clinical and urographic findings for signs of renal artery injury which would mandate angiographic assessment.

  9. Error corrections for quantitative thermal neutron computed tomography

    NASA Astrophysics Data System (ADS)

    Shi, Liang

    A state-of-the art, two mirror reflection, combination of a Li-6 scintillation screen and a cooled CCD camera high spatial resolution neutron radioscopy imaging system was designed and developed in the RSEC at Penn State. Radiation shielding was applied to the imaging system to achieve a higher spatial resolution. Modulation Transfer Function (MTF) analysis shows that a spatial resolution of 116 microns was achieved. The imaging system was successfully applied for diagnostic measurements of hydrogen fuel cells. A quantitative neutron computed tomography NCT model was developed which confirmed the fundamental computed tomography theory. The model justified the partial volume neutron computed tomography water/ice mass evaluation technique which was designed and tested by Heller. The evaluation results of the water/ice mass using the NCT method was very close to the theoretical value. Sample and background neutron scattering effects were considered as one of the errors that influenced the accuracy of the quantitative measurement using the NCT method. The neutron scattering effect induced cupping artifacts that also contributed to the error in the measurement of water/ice mass using NCT. One method was developed to reduce the cupping artifacts in the reconstruction slice of the water/ice column. The geometric unsharpness, Ug, was demonstrated as the predominant source of error for the accuracy of the 3-D water/ice mass evaluation technique. A unique method was established to reduce the divergence neutron beam associated geometric unsharpness Ug. Compared to the de-convolution algorithm used in de-blurring the image projection, the method has the advantage of minimizing the unsharpness while keeping the degree of cupping through the water column the same. For the 3-D water/ice mass evaluation purpose, this method is a better choice for the water quantification technique error correction.

  10. SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHY: COMPENSATION FOR CONSTANT ATTENUATION

    SciTech Connect

    Gullberg, Grant T.; Budinger, Thomas F.

    1980-06-01

    A back-projection of filtered projection (BKFIL) reconstruction algorithm is presented that is applicable to single-photon emission computed tomography (ECT) in the presence of a constant attenuating medium such as the brain. The filters used in transmission computed tomography (TCT) - comprised of a ramp multiplied by window functions - are modified so that the single-photon ECT filter is a function of the constant attenuation coefficient. The filters give good reconstruction results with sufficient angular and lateral sampling. With continuous samples the BKFIL algorithm has a point spread function that is the Hankel transform of the window function. The resolution and s tistical properties of the filters are demonstrated by various simulations. Statistical formulas for the reconstructed image show that the square of the percent-root-mean square uncertainty (%RMS) of the reconstruction is inversely proportional to the total measured counts. The results indicate that constant attenuation can be compensated for in single-photon ECT by using an attenuation-dependent filter that reconstructs the transverse section reliably. Computer time requirements are two times that of conventional TCT or positron ECT and there is no increase in memory requirements.

  11. [Producing the third dimension of flat radiographic images: analogue tomography - computer tomography].

    PubMed

    Praestholm, J

    1995-01-01

    The inventor of computer tomography, Godfrey N. Hounsfield, mentioned in his Nobel Foundation lecture the following three main problems of conventional radiography: 1. It depicts the sum of shadows from several tissue elements at the same spot of the film. 2. The sensitivity of the employed photographic medium does not allow to differentiate between various soft tissue densities. 3. It gives no exact measure characterizing tissue densities. The first part of this article is dealing with the solution of problem number one. Researchers within medical imaging from many countries developed independently of each other a variety of methods for body-sectional imaging methods, but he did not construct any equipment. Alessandro Vallebona constructed equipment and published the first clinical body-section imaging material ever in 1930, but his method was not ideal. The first clinical material employing an ideal method was published by Bernhard Ziedses des Plantes in 1932. Methods for transverse axial tomography was independently described by William Watson in 1937, Jean Kieffer in 1938, and Shinji Takahashi in 1947. The limitation in sensitivity of the photographic medium was revealed in parallel to this development. In 1963 Allan M. Cormack described the mathematical model for absorption of ionizing rays in inhomogenous tissue. Godfrey N. Hounsfield combined this knowledge of mathematics with the fast developing computer technology and the medical need for a more sensitive registration medium. In 1971 computer tomography was a reality. One of the greatest conquests in medicine of this century had been made. Recent developments within scanner technology predict still better and safer diagnostic possibilities.

  12. Tomography of Band Insulators from Quench Dynamics

    NASA Astrophysics Data System (ADS)

    Hauke, Philipp; Lewenstein, Maciej; Eckardt, André

    2014-07-01

    We propose a simple scheme for tomography of band-insulating states in one- and two-dimensional optical lattices with two sublattice states. In particular, the scheme maps out the Berry curvature in the entire Brillouin zone and extracts topological invariants such as the Chern number. The measurement relies on observing—via time-of-flight imaging—the time evolution of the momentum distribution following a sudden quench in the band structure. We consider two examples of experimental relevance: the Harper model with π flux and the Haldane model on a honeycomb lattice. Moreover, we illustrate the performance of the scheme in the presence of a parabolic trap, noise, and finite measurement resolution.

  13. Computed Tomography in the Diagnosis of Intra-abdominal Abscesses

    PubMed Central

    Daffner, Richard H.; Halber, Michael D.; Morgan, Carlisle L.; Trought, William S.; Thompson, William M.; Rice, Reed P.

    1979-01-01

    The diagnosis of intra-abdominal abscess by radiographic means often relies on combining the results of several different imaging modalities. Computed tomography (CT) has been shown to be a safe, accurate and rapid diagnostic method of diagnosing these abscesses. Five patients with a variety of intra-abdominal abscesses are presented in whom the CT scan alone provided the correct diagnosis. The various imaging modalities available for the radiologic diagnosis of intra-abdominal abscess are described and are compared to CT diagnosis regarding their pitfalls. ImagesFig. 1.Fig. 2.Fig. 3.Fig. 4.Fig. 5.Fig.5.C. PMID:758860

  14. Multimodality Imaging in Coronary Artery Disease: Focus on Computed Tomography

    PubMed Central

    Lee, Ji Hyun; Han, Donghee; Danad, Ibrahim; Hartaigh, Bríain ó; Lin, Fay Y.

    2016-01-01

    Coronary artery disease (CAD) is the leading cause of mortality worldwide, and various cardiovascular imaging modalities have been introduced for the purpose of diagnosing and determining the severity of CAD. More recently, advances in computed tomography (CT) technology have contributed to the widespread clinical application of cardiac CT for accurate and noninvasive evaluation of CAD. In this review, we focus on imaging assessment of CAD based upon CT, which includes coronary artery calcium screening, coronary CT angiography, myocardial CT perfusion, and fractional flow reserve CT. Further, we provide a discussion regarding the potential implications, benefits and limitations, as well as the possible future directions according to each modality. PMID:27081438

  15. Multidetector computer tomography: evaluation of blunt chest trauma in adults.

    PubMed

    Palas, João; Matos, António P; Mascarenhas, Vasco; Herédia, Vasco; Ramalho, Miguel

    2014-01-01

    Imaging plays an essential part of chest trauma care. By definition, the employed imaging technique in the emergency setting should reach the correct diagnosis as fast as possible. In severe chest blunt trauma, multidetector computer tomography (MDCT) has become part of the initial workup, mainly due to its high sensitivity and diagnostic accuracy of the technique for the detection and characterization of thoracic injuries and also due to its wide availability in tertiary care centers. The aim of this paper is to review and illustrate a spectrum of characteristic MDCT findings of blunt traumatic injuries of the chest including the lungs, mediastinum, pleural space, and chest wall. PMID:25295188

  16. PRaVDA: High Energy Physics towards proton Computed Tomography

    NASA Astrophysics Data System (ADS)

    Price, T.

    2016-07-01

    Proton radiotherapy is an increasingly popular modality for treating cancers of the head and neck, and in paediatrics. To maximise the potential of proton radiotherapy it is essential to know the distribution, and more importantly the proton stopping powers, of the body tissues between the proton beam and the tumour. A stopping power map could be measured directly, and uncertainties in the treatment vastly reduce, if the patient was imaged with protons instead of conventional x-rays. Here we outline the application of technologies developed for High Energy Physics to provide clinical-quality proton Computed Tomography, in so reducing range uncertainties and enhancing the treatment of cancer.

  17. Differential diagnosis of intrasellar tumors by computed tomography

    SciTech Connect

    Daniels, D.L.; Williams, A.L.; Thornton, R.S.; Meyer, G.A.; Cusick, J.F.; Haughton, V.M.

    1981-12-01

    The specificity of the computed tomography (CT) diagnosis of intrasellar adenoma has not been studied. We compared the CT findings in intrasellar meningiomas, craniopharyngiomas, aneurysms, and metastases with those of pituitary adenomas. Calcification was a feature of intrasellar meningiomas, aneurysms, and craniopharyngiomas, but not a typical feature of adenomas. Low-density regions representing necrosis or cyst were found in most types of intrasellar tumors. Eccentricity, hyperostosis, and bone destruction were useful signs of aneurysm, meningioma, and metastasis, respectively. Since adenoma cannot always be distinghished from another intrasellar mass, angiography to demonstrate tumor angioarchitecture may be needed to characterize some neoplasms or to confirm an intrasellar aneurysm.

  18. Computer Tomography Analysis of Fastrac Composite Thrust Chamber Assemblies

    NASA Technical Reports Server (NTRS)

    Beshears, Ronald D.

    2000-01-01

    Computed tomography (CT) inspection has been integrated into the production process for NASA's Fastrac composite thrust chamber assemblies (TCAs). CT has been proven to be uniquely qualified to detect the known critical flaw for these nozzles, liner cracks that are adjacent to debonds between the liner and overwrap. CT is also being used as a process monitoring tool through analysis of low density indications in the nozzle overwraps. 3d reconstruction of CT images to produce models of flawed areas is being used to give program engineers better insight into the location and nature of nozzle flaws.

  19. Reduction of phase artifacts in differential phase contrast computed tomography.

    PubMed

    Jerjen, Iwan; Revol, Vincent; Schuetz, Philipp; Kottler, Christian; Kaufmann, Rolf; Luethi, Thomas; Jefimovs, Konstantins; Urban, Claus; Sennhauser, Urs

    2011-07-01

    X-ray differential phase contrast computed tomography (DPC CT) with a Talbot-Lau interferometer setup allows visualizing the three-dimensional distribution of the refractive index by measuring the shifts of an interference pattern due to phase variations of the X-ray beam. Unfortunately, severe reconstruction artifacts appear in the presence of differential phase wrapping and clipping. In this paper, we propose to use the attenuation contrast, which is obtained from the same measurement, for correcting the DPC signal. Using the example of a DPC CT measurement with pronounced phase artifacts, we will discuss the efficiency of our phase artifact correction method. PMID:21747516

  20. [THE ROLE OF COMPUTER TOMOGRAPHY WHILE CHOOSING THE ABDOMINOPLASTY METHOD].

    PubMed

    Galych, S P; Symulyk, E V

    2016-03-01

    The role of computer tomography (CT), while choosing the abdominoplasty method in the patients with different types of the anterior abdominal wall deformity present. For CT date the anterior abdominal wall deformity type was determined in the accordance to it--the operation volume needed. Depending on the changes degree the patients were divided on 5 groups, and in accordance to the deformity type present a necessary correction was made. The CT application have had permitted to determine the changes degree in the anterior abdominal wall, and to choose a necessary volume of abdominoplasty precisely. PMID:27514090

  1. The value of computed tomography in myasthenia gravis

    SciTech Connect

    Brown, L.R.; Muhm, J.R.; Sheedy, P.F. II; Unni, K.K.; Bernatz, P.E.; Hermann, R.C. Jr.

    1983-01-01

    In a 5 year study, 19 patients with myasthenia gravis were studied by computed tomography (CT) and underwent thymectomy. CT was accurate in detecting the nine true thymic masses but could not differentiate thymomas from nonthymomatous masses, including thymic cysts. No thymoma was found in a patient under 25 years of age. In one case, the 18 sec scanner could not differentiate a large gland from a thymoma. In eight cases, glands with histologic thymic hyperplasia and histologically normal thymus appeared to be similar and could not be differentiated by CT.

  2. Cardiac PET/Computed Tomography Applications and Cardiovascular Outcome.

    PubMed

    Schindler, Thomas Hellmut

    2015-07-01

    Cardiac PET/computed tomography (CT) in conjunction with different blood flow tracers is increasingly applied for the assessment of myocardial perfusion and myocardial flow reserve (MFR) in the detection of coronary artery disease (CAD). The ability of PET/CT to noninvasively determine regional myocardial blood flow at rest and during vasomotor stress allows the calculation of the MFR, which carries important prognostic information in patients with subclinical forms of cardiomyopathy. The measured MFR optimizes the identification and characterization of the extent and severity of CAD burden, and contributes to the flow-limiting effect of single lesions in multivessel CAD. PMID:26099678

  3. Computed tomography of CNS disease. A teaching file

    SciTech Connect

    Yock, D.H.

    1985-01-01

    This ''teaching file'' comprises a clinically representative collection of over 400 cases of neuropathology diagnosed by computed tomography. Each case is accompanied by a discussion of CT interpretation. Comments on clinical presentation, pathophysiological findings, and therapy are included where appropriate. Abnormalities covered include metastases, meningiomas, posterior fossa tumors inflammatory and degenerative diseases, infarction and anoxia, and spinal lesions. Each pathological category demonstrates a range of CT findings from ''classic'' patterns to atypical examples. Anatomical variants are included only if they mimic pathology. Diverse lesions that potentially resemble each other are highlighted throughout the book in special sections entitled, ''Differential Diagnoses''.

  4. Unsuspected colorectal carcinoma on routine abdominopelvic computed tomography.

    PubMed

    Lee, Su Ann; Poh, Angeline

    2015-05-01

    Colorectal carcinoma is a common lethal disease with signs and symptoms that may be nonspecific. Computed tomography (CT) of the abdomen and pelvis with or without contrast is frequently performed for various general abdominal complaints, but unlike CT colonography, the large bowel may not be optimally prepared for evaluation. As such, careful and diligent assessment of the non-prepared colon in all CT images of the abdomen and pelvis is important, as it ensures that incidental colorectal malignancy is not missed, especially in older patients. This article gives an overview of multidetector CT imaging signs and subtle clues to aid in the diagnosis of colorectal carcinoma, as well as their pitfalls.

  5. Micro Computer Tomography for medical device and pharmaceutical packaging analysis.

    PubMed

    Hindelang, Florine; Zurbach, Raphael; Roggo, Yves

    2015-04-10

    Biomedical device and medicine product manufacturing are long processes facing global competition. As technology evolves with time, the level of quality, safety and reliability increases simultaneously. Micro Computer Tomography (Micro CT) is a tool allowing a deep investigation of products: it can contribute to quality improvement. This article presents the numerous applications of Micro CT for medical device and pharmaceutical packaging analysis. The samples investigated confirmed CT suitability for verification of integrity, measurements and defect detections in a non-destructive manner. PMID:25710902

  6. Dual-energy computed tomography applications in uroradiology.

    PubMed

    Park, Jong; Chandarana, Hersh; Macari, Michael; Megibow, Alec J

    2012-02-01

    The introduction of dual-energy computed tomography systems (ie, scanners that can simultaneously acquire images at different energies) has significant and unique applications for urologists. Imaging data from these scanners can be used to evaluate composition of urinary calculi and, by "removing" iodine from an image, significantly decrease radiation dose to patients referred for hematuria. Further, the ability to create a virtual noncontrast image obviates the need for repeated scanning in patients with incidentally detected renal and adrenal masses. Finally, the ability to quantify the regional concentration of iodine in a renal neoplasm may provide a method to monitor effectiveness of therapy before size changes become apparent.

  7. Non-functioning adrenal adenomas discovered incidentally on computed tomography

    SciTech Connect

    Mitnick, J.S.; Bosniak, M.A.; Megibow, A.J.; Naidich, D.P.

    1983-08-01

    Eighteen patients with unilateral non-metastatic non-functioning adrenal masses were studied with computed tomography (CT). Pathological examination in cases revealed benign adrenal adenomas. The others were followed up with serial CT scans and found to show no change in tumor size over a period of six months to three years. On the basis of these findings, the authors suggest certain criteria of a benign adrenal mass, including (a) diameter less than 5 cm, (b) smooth contour, (c) well-defined margin, and (d) no change in size on follow-up. Serial CT scanning can be used as an alternative to surgery in the management of many of these patients.

  8. Computed tomography in the evaluation of thyroid disease

    SciTech Connect

    Silverman, P.M.; Newman, G.E.; Korobkin, M.; Workman, J.B.; Moore, A.V.; Coleman, R.E.

    1984-05-01

    Traditionally, thyroid imaging has been performed primarily using radionuclide scanning. High-resolution computed tomography (CT) was performed in 18 patients to evaluate the CT appearance of various thyroid abnormalities including diffuse toxic goiter, multinodular goiter, Hashimoto thyroiditis, thyroid adenoma, and malignant thyroid tumors. CT images of the thyroid were correlated with radionuclide scanning, surgical findings, and clinical and laboratory results. CT provided a complementary method for evaluation of the thyroid by defining the morphology of the thyroid gland and more precisely defining the anatomic extent of thyroid abnormalities in relation to the normal structures of the neck and mediastinum.

  9. Internal mammary lymph node biopsy guided by computed tomography

    PubMed Central

    Irving, Henry C.; Hardy, Graham J.

    1982-01-01

    Internal mammary lymph node enlargement may be demonstrated using computed tomography (CT), and a confirmatory tissue diagnosis of metastatic involvement may be obtained using fine needle aspiration biopsy with needle tip placement guided by the CT scanner. A case history is described to illustrate how a patient presented 9 years after mastectomy with an internal mammary lymph node metastasis and how cytopathological diagnosis of this metastasis was achieved by CT guided biopsy. ImagesFig. 1Fig. 2Fig. 3Fig. 4 PMID:7145793

  10. Multidetector Computer Tomography: Evaluation of Blunt Chest Trauma in Adults

    PubMed Central

    Matos, António P.; Mascarenhas, Vasco; Herédia, Vasco

    2014-01-01

    Imaging plays an essential part of chest trauma care. By definition, the employed imaging technique in the emergency setting should reach the correct diagnosis as fast as possible. In severe chest blunt trauma, multidetector computer tomography (MDCT) has become part of the initial workup, mainly due to its high sensitivity and diagnostic accuracy of the technique for the detection and characterization of thoracic injuries and also due to its wide availability in tertiary care centers. The aim of this paper is to review and illustrate a spectrum of characteristic MDCT findings of blunt traumatic injuries of the chest including the lungs, mediastinum, pleural space, and chest wall. PMID:25295188

  11. Multidetector computer tomography: evaluation of blunt chest trauma in adults.

    PubMed

    Palas, João; Matos, António P; Mascarenhas, Vasco; Herédia, Vasco; Ramalho, Miguel

    2014-01-01

    Imaging plays an essential part of chest trauma care. By definition, the employed imaging technique in the emergency setting should reach the correct diagnosis as fast as possible. In severe chest blunt trauma, multidetector computer tomography (MDCT) has become part of the initial workup, mainly due to its high sensitivity and diagnostic accuracy of the technique for the detection and characterization of thoracic injuries and also due to its wide availability in tertiary care centers. The aim of this paper is to review and illustrate a spectrum of characteristic MDCT findings of blunt traumatic injuries of the chest including the lungs, mediastinum, pleural space, and chest wall.

  12. [The different manifestations of pulmonary aspergillosis: multidetector computed tomography findings].

    PubMed

    Koren Fernández, L; Alonso Charterina, S; Alcalá-Galiano Rubio, A; Sánchez Nistal, M A

    2014-01-01

    Pulmonary aspergillosis is a fungal infection usually caused by inhaling Aspergillus fumigatus spores. However, when we talk about aspergillosis, we normally refer to the spectrum of clinical and radiological findings that depend directly on the patient's immune status, on the prior existence of lung disease, and on the virulence of the infective organism. There are four types of pulmonary aspergillosis (aspergilloma, allergic bronchopulmonary aspergillosis, chronic necrotizing pulmonary aspergillosis, and invasive aspergillosis), and each type has its own distinct radiologic findings. We review the signs of pulmonary aspergillosis on multidetector computed tomography and we correlate them with patients' symptoms and immune responses. Likewise, we discuss the differential diagnoses.

  13. Diagnosis of skeletal injuries in Chelonians using computed tomography.

    PubMed

    Abou-Madi, Noha; Scrivani, Peter V; Kollias, George V; Hernandez-Divers, Sonia M

    2004-06-01

    Computed tomography (CT) was used to diagnose the cause of lameness in a radiated tortoise (Geochelone radiata) and to determine the extent of shell and skeletal trauma in two snapping turtles (Chelydra serpentina). The radiated tortoise's lameness was ultimately attributed to luxation of the right-shoulder joint that was not detected during plain film radiography. Axial and appendicular fractures were identified in one of the snapping turtles that were not detected during plain film radiography. In each patient, the information obtained during CT provided important diagnostic, therapeutic, or prognostic information. PMID:15305520

  14. Assessment of cardiac function: magnetic resonance and computed tomography.

    PubMed

    Greenberg, S B

    2000-10-01

    A complete cardiac study requires both anatomic and physiologic evaluation. Cardiac function can be evaluated noninvasively by magnetic resonance imaging (MRI)or ultrafast computed tomography (CT). MRI allows for evaluation of cardiac function by cine gradient echo imaging of the ventricles and flow analysis across cardiac valves and the great vessels. Cine gradient echo imaging is useful for evaluation of cardiac wall motion, ventricular volumes and ventricular mass. Flow analysis allows for measurement of velocity and flow during the cardiac cycle that reflects cardiac function. Ultrafast CT allows for measurement of cardiac indices similar to that provided by gradient echo imaging of the ventricles.

  15. Colour perfusion imaging: a new application of computed tomography.

    PubMed

    Miles, K A; Hayball, M; Dixon, A K

    1991-03-16

    We describe a new application for imaging with computed tomography (CT) in which a quantifiable map of tissue perfusion is created and displayed by means of a colour scale. A rapid sequence of images is acquired without table movement immediately after a bolus intravenous injection of radiographic contrast medium. The rate of enhancement in each pixel within the chosen slice can then be used to determine perfusion. The technique provides a quantifiable display of regional perfusion combined with the high spatial resolution afforded by CT.

  16. PET/Computed Tomography in Renal, Bladder, and Testicular Cancer.

    PubMed

    Bouchelouche, Kirsten; Choyke, Peter L

    2015-07-01

    Imaging plays an important role in the clinical management of cancer patients. Hybrid imaging with PET/computed tomography (CT) is having a broad impact in oncology, and in recent years PET/CT is beginning to have an impact in urooncology. In both bladder and renal cancers, there is a need to study the efficacy of other tracers than F-18 fluorodeoxyglucose (FDG), particularly tracers with limited renal excretion. Thus, new tracers are being introduced. This review focuses on the clinical role of FDG and other PET agents in renal, bladder, and testicular cancers.

  17. Computed Tomography Imaging Artifact Simulating Type A Aortic Dissection

    PubMed Central

    Chou, Alan S.; Ziganshin, Bulat A.; Elefteriades, John A.

    2016-01-01

    Contrast-enhanced computed tomography (CT) is an effective tool for assessment of thoracic aortic disease in the modern era. Here, we describe a case of Type A aortic dissection incidentally detected by CT in a 63-year old man. Upon more precise imaging with electrocardiography (ECG)-gated CT, the dissection vanished, revealing it to be an aortic motion artifact. This report highlights the importance of motion artifacts mimicking a dissection flap. CT imaging gated with ECG can distinguish a dissection flap from an artifact.

  18. Clinical experience with the first combined positron emission tomography/computed tomography scanner in Australia.

    PubMed

    Lau, W F Eddie; Binns, David S; Ware, Robert E; Ramdave, Shakher; Cachin, Florent; Pitman, Alexander G; Hicks, Rodney J

    2005-02-21

    Metabolic imaging with fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) is increasing rapidly worldwide because of superior accuracy compared with conventional non-invasive techniques used for evaluating cancer. Limited anatomical information from FDG-PET images alone dictates that complementary use with structural imaging is required to optimise benefit. Recently, combined positron emission tomography/computed tomography (PET/CT) scanners have overtaken standalone PET scanners as the most commonly purchased PET devices. We describe our experience of over 5500 scans performed since the first PET/CT scanner in Australia was commissioned at the Peter MacCallum Cancer Centre (PMCC), Melbourne, in January 2002. Clinical indications for PET/CT scans performed at PMCC largely reflect current Medicare reimbursement policy. Advantages of PET/CT include greater patient comfort and higher throughput, greater diagnostic certainty and accuracy, improved biopsy methods, and better treatment planning. We believe PET/CT will underpin more effective and efficient imaging paradigms for many common tumours, and lead to a decrease in imaging costs. PMID:15720173

  19. Observation of the pulp horn by swept source optical coherence tomography and cone beam computed tomography

    NASA Astrophysics Data System (ADS)

    Iino, Yoshiko; Yoshioka, Toshihiko; Hanada, Takahiro; Ebihara, Arata; Sunakawa, Mitsuhiro; Sumi, Yasunori; Suda, Hideaki

    2015-02-01

    Cone-beam computed tomography (CBCT) is one of the most useful diagnostic techniques in dentistry but it involves ionizing radiation, while swept source optical coherence tomography (SS-OCT) has been introduced recently as a nondestructive, real-time, high resolution imaging technique using low-coherence interferometry, which involves no ionizing radiation. The purpose of this study was to evaluate the ability of SS-OCT to detect the pulp horn (PH) in comparison with that of CBCT. Ten extracted human mandibular molars were used. After horizontally removing a half of the tooth crown, the distance from the cut dentin surface to PH was measured using microfocus computed tomography (Micro CT) (SL) as the gold standard, by CBCT (CL) and by SS-OCT (OL). In the SS-OCT images, only when PH was observed beneath the overlying dentin, the distance from the cut dentin surface to PH was recorded. If the pulp was exposed, it was defined as pulp exposure (PE). The results obtained by the above three methods were statistically analyzed by Spearman's rank correlation coefficient at a significance level of p < 0.01. SS-OCT detected the presence of PH when the distance from the cut dentin surface to PH determined by SL was 2.33 mm or less. Strong correlations of the measured values were found between SL and CL (r=0.87), SL and OL (r=0.96), and CL and OL (r=0.86). The results showed that SS-OCT images correlated closely with CBCT images, suggesting that SS-OCT can be a useful tool for the detection of PH.

  20. Neutron computed tomography of plasma facing components for fusion experiments

    NASA Astrophysics Data System (ADS)

    Schillinger, B.; Greuner, H.; Linsmeier, Ch.

    2011-09-01

    In nuclear fusion experiments, divertor plates are used to remove energy and particles from the plasma. These divertor plates can be made of water-cooled copper heat sinks covered by carbon fiber composite (CFC) protection tiles. During operation, surface temperatures in excess of 1000 °C are reached for typical heat loads of 10 MW/m 2. The large mismatch in the coefficients of thermal expansion for CFC and Cu causes high stresses and possibly bonding defects. Growing joint defects, which lead to unacceptable overheating of the protection tiles, are critical for the lifetime of the components. A prototype component was subjected to 10,000 cycles at 10 MW/m 2 to study the crack growth mechanism. Neutron computed tomography offers the possibility to analyze such structures on centimeter-sized samples non-destructively with a high spatial resolution. At the ANTARES neutron imaging facility of the FRM II reactor, the samples were loaded with a contrast agent and examined with neutron computed tomography.

  1. Radiation doses from computed tomography practice in Johor Bahru, Malaysia

    NASA Astrophysics Data System (ADS)

    Karim, M. K. A.; Hashim, S.; Bradley, D. A.; Bakar, K. A.; Haron, M. R.; Kayun, Z.

    2016-04-01

    Radiation doses for Computed Tomography (CT) procedures have been reported, encompassing a total of 376 CT examinations conducted in one oncology centre (Hospital Sultan Ismail) and three diagnostic imaging departments (Hospital Sultanah Aminah, Hospital Permai and Hospital Sultan Ismail) at Johor hospital's. In each case, dose evaluations were supported by data from patient questionnaires. Each CT examination and radiation doses were verified using the CT EXPO (Ver. 2.3.1, Germany) simulation software. Results are presented in terms of the weighted computed tomography dose index (CTDIw), dose length product (DLP) and effective dose (E). The mean values of CTDIw, DLP and E were ranged between 7.6±0.1 to 64.8±16.5 mGy, 170.2±79.2 to 943.3±202.3 mGy cm and 1.6±0.7 to 11.2±6.5 mSv, respectively. Optimization techniques in CT are suggested to remain necessary, with well-trained radiology personnel remaining at the forefront of such efforts.

  2. Computed tomography for planning transcatheter aortic valve replacement.

    PubMed

    Apfaltrer, Paul; Henzler, Thomas; Blanke, Phillip; Krazinski, Aleksander W; Silverman, Justin R; Schoepf, U Joseph

    2013-07-01

    Transcatheter aortic valve replacement (TAVR) is rapidly becoming a widely used alternative to surgical aortic valve replacement (SAVR) in patients with severe aortic stenosis at high surgical risk. In these patients, TAVR has been associated with markedly improved survival and relief from symptoms. Despite a very-high risk patient profile, recent multicenter registries have confirmed the safety and efficacy of this procedure. Moreover, the randomized, controlled PARTNER (Placement of AoRTic TraNscathetER Valves) trial has confirmed both the superiority of TAVR over medical treatment in patients not considered to be candidates for standard SAVR and the noninferiority of TAVR compared with SAVR in high-risk patients. The TAVR procedure requires a comprehensive preinterventional diagnostic workup. Above all, detailed information on the anatomy of the aortic annulus (AA) and the relation of the AA to the coronary arteries is essential to avoid complications. So far, no imaging reference standard for AA sizing has been established. Echocardiography, catheter angiography, and computed tomography angiography are widely and often complementarily used imaging techniques for this purpose. Compared with 2-dimensional imaging techniques, computed tomography (CT) has been proven to provide comprehensive information on AA anatomy and geometry, supporting appropriate patient selection and prosthesis sizing. In addition, CT is gaining an increasing role in evaluating the vascular access route before the procedure. This article describes the rapidly emerging role of CT in the context of pre-TAVR assessment.

  3. Can Dental Cone Beam Computed Tomography Assess Bone Mineral Density?

    PubMed Central

    2014-01-01

    Mineral density distribution of bone tissue is altered by active bone modeling and remodeling due to bone complications including bone disease and implantation surgery. Clinical cone beam computed tomography (CBCT) has been examined whether it can assess oral bone mineral density (BMD) in patient. It has been indicated that CBCT has disadvantages of higher noise and lower contrast than conventional medical computed tomography (CT) systems. On the other hand, it has advantages of a relatively lower cost and radiation dose but higher spatial resolution. However, the reliability of CBCT based mineral density measurement has not yet been fully validated. Thus, the objectives of this review are to discuss 1) why assessment of BMD distribution is important and 2) whether the clinical CBCT can be used as a potential tool to measure the BMD. Brief descriptions of image artefacts associated with assessment of gray value, which has been used to account for mineral density, in CBCT images are provided. Techniques to correct local and conversion errors in obtaining the gray values in CBCT images are also introduced. This review can be used as a quick reference for users who may encounter these errors during analysis of CBCT images. PMID:25006568

  4. Alternative methods of obtaining the computed tomography dose index.

    PubMed

    Knox, H H; Gagne, R M

    1996-08-01

    The most direct way of getting the value of the multiple scan average dose (MSAD) in computed tomography is to employ a pencil chamber for integration of a single scan dose profile. Because the active length of the pencil chamber is fixed, the measurement can represent the value of the MSAD from a different number of contiguous scans depending on the slice thickness. This characteristic makes it difficult to compare the value of MSAD using the pencil chamber to the information required by Federal regulations on the computed tomography dose index (CTDI). The CTDI, which is the MAD at the center of a set of 14 contiguous scans, is the dose descriptor used in the Federal Performance Standard. Two alternative methods were developed to make the CTDI measurements at the center of a CT dosimetry phantom. These alternative methods were compared to the results of thermoluminescent dosimeter (TLD) measurements from more than 20 different CT scanners. One alternative method involved the use of radio-opaque sleeves with the pencil chamber to limit the length of the single scan dose profile incident on the pencil chamber. In addition, the TLD data were also used to obtain a set of conversion factors for converting the results of a measurement with the pencil chamber without a radio-opaque sleeve to a value of the CTDI. The alternative methods of obtaining the CTDI agree on the average to better than 10% for all values of slice thickness on the different CT scanners.

  5. X-ray computed tomography using curvelet sparse regularization

    SciTech Connect

    Wieczorek, Matthias Vogel, Jakob; Lasser, Tobias; Frikel, Jürgen; Demaret, Laurent; Eggl, Elena; Pfeiffer, Franz; Kopp, Felix; Noël, Peter B.

    2015-04-15

    Purpose: Reconstruction of x-ray computed tomography (CT) data remains a mathematically challenging problem in medical imaging. Complementing the standard analytical reconstruction methods, sparse regularization is growing in importance, as it allows inclusion of prior knowledge. The paper presents a method for sparse regularization based on the curvelet frame for the application to iterative reconstruction in x-ray computed tomography. Methods: In this work, the authors present an iterative reconstruction approach based on the alternating direction method of multipliers using curvelet sparse regularization. Results: Evaluation of the method is performed on a specifically crafted numerical phantom dataset to highlight the method’s strengths. Additional evaluation is performed on two real datasets from commercial scanners with different noise characteristics, a clinical bone sample acquired in a micro-CT and a human abdomen scanned in a diagnostic CT. The results clearly illustrate that curvelet sparse regularization has characteristic strengths. In particular, it improves the restoration and resolution of highly directional, high contrast features with smooth contrast variations. The authors also compare this approach to the popular technique of total variation and to traditional filtered backprojection. Conclusions: The authors conclude that curvelet sparse regularization is able to improve reconstruction quality by reducing noise while preserving highly directional features.

  6. Incidental findings on cone beam computed tomography images.

    PubMed

    Allareddy, Veeratrishul; Vincent, Steven D; Hellstein, John W; Qian, Fang; Smoker, Wendy R K; Ruprecht, Axel

    2012-01-01

    Background. Cone beam computed tomography (CBCT) has gained widespread acceptance in dentistry for a variety of applications. Most dentists who are not radiologists/trained in radiology are generally not familiar with interpretation of anatomical structures and/or pathosis outside their area of primary interest, as often this was not within the scope of their training. Objectives. To assess that the number of incidental findings on a CBCT scan is high both within and outside of the primary area of interest, thereby emphasizing the importance of interpretation of all areas visualized on the scan. Materials and Methods. An oral and maxillofacial radiologist reviewed 1000 CBCT scans (382 males and 618 females) for findings both in- and outside the area of interest. Results. Of the 1000 subjects that were reviewed, 943 scans showed findings in the primary regions of interest and/or outside the regions of interest, and 76 different conditions were visualized in these scans both in and outside the areas of interest. Conclusion. From the wide scope of findings noted on these scans, it can be concluded that it is essential that a person trained in advanced interpretation techniques in radiology interprets cone beam computed tomography scans.

  7. Glandular dose in breast computed tomography with synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Mettivier, G.; Fedon, C.; Di Lillo, F.; Longo, R.; Sarno, A.; Tromba, G.; Russo, P.

    2016-01-01

    The purpose of this work is to provide an evaluation of the mean glandular dose (MGD) for breast computed tomography (CT) with synchrotron radiation in an axial scanning configuration with a partial or total organ volume irradiation, for the in vivo program of breast CT ongoing at the ELETTRA facility (Trieste, Italy). A Geant4 Monte Carlo code was implemented, simulating the photon irradiation from a synchrotron radiation source in the energetic range from 8 to 50 keV with 1 keV intervals, to evaluate the MGD. The code was validated with literature data, in terms of mammographic normalized glandular dose coefficients (DgN) and with ad hoc experimental data, in terms of computed tomography dose index (CTDI). Simulated cylindrical phantoms of different sizes (diameter at phantom base 8, 10, 12, 14 or 16 cm, axial length 1.5 times the radius) and glandular fraction by weight (0%, 14.3%, 25%, 50%, 75% and 100%) were implemented into the code. The validation of the code shows an excellent agreement both with previously published work and in terms of DgN and CDTI measurements. The implemented simulations show a dependence of the glandular dose estimate on the vertical dimension of the irradiated zone when a partial organ irradiation was implemented. Specific normalized coefficients for calculating the MGD to the whole breast or to the single irradiated slice were reported.

  8. Cardiac computed tomography in patients with acute chest pain.

    PubMed

    Nieman, Koen; Hoffmann, Udo

    2015-04-14

    The efficient and reliable evaluation of patients with acute chest pain is one of the most challenging tasks in the emergency department. Coronary computed tomography (CT) angiography may play a major role, since it permits ruling out coronary artery disease with high accuracy if performed with expertise in properly selected and prepared patients. Several randomized trials have established early cardiac CT as a viable safe and potentially more efficient alternative to functional testing in the evaluation of acute chest pain. Ongoing investigations explore whether advanced anatomic and functional assessments such as high-risk coronary plaque, resting myocardial perfusion, and left ventricular function, or the simulation of the fractional coronary flow reserve will add information to the anatomic assessment for stenosis, which would allow expanding the benefits of cardiac CT from triage to treatment decisions. Especially, the combination of high-sensitive troponins and coronary computed tomography angiography may play a valuable role in future strategies for the management of patients presenting with acute chest pain.

  9. Acute Perforated Diverticulitis: Assessment With Multidetector Computed Tomography.

    PubMed

    Sessa, Barbara; Galluzzo, Michele; Ianniello, Stefania; Pinto, Antonio; Trinci, Margherita; Miele, Vittorio

    2016-02-01

    Colonic diverticulitis is a common condition in the western population. Complicated diverticulitis is defined as the presence of extraluminal air or abscess, peritonitis, colon occlusion, or fistulas. Multidetector row computed tomography (MDCT) is the modality of choice for the diagnosis and the staging of diverticulitis and its complications, which enables performing an accurate differential diagnosis and addressing the patients to a correct management. MDCT is accurate in diagnosing the site of perforation in approximately 85% of cases, by the detection of direct signs (focal bowel wall discontinuity, extraluminal gas, and extraluminal enteric contrast) and indirect signs, which are represented by segmental bowel wall thickening, abnormal bowel wall enhancement, perivisceral fat stranding of fluid, and abscess. MDCT is accurate in the differentiation from complicated colon diverticulitis and colon cancer, often with a similar imaging. The computed tomography-guided classification is recommended to discriminate patients with mild diverticulitis, generally treated with antibiotics, from those with severe diverticulitis with a large abscess, which may be drained with a percutaneous approach.

  10. Glandular dose in breast computed tomography with synchrotron radiation.

    PubMed

    Mettivier, G; Fedon, C; Di Lillo, F; Longo, R; Sarno, A; Tromba, G; Russo, P

    2016-01-21

    The purpose of this work is to provide an evaluation of the mean glandular dose (MGD) for breast computed tomography (CT) with synchrotron radiation in an axial scanning configuration with a partial or total organ volume irradiation, for the in vivo program of breast CT ongoing at the ELETTRA facility (Trieste, Italy). A Geant4 Monte Carlo code was implemented, simulating the photon irradiation from a synchrotron radiation source in the energetic range from 8 to 50 keV with 1 keV intervals, to evaluate the MGD. The code was validated with literature data, in terms of mammographic normalized glandular dose coefficients (DgN) and with ad hoc experimental data, in terms of computed tomography dose index (CTDI). Simulated cylindrical phantoms of different sizes (diameter at phantom base 8, 10, 12, 14 or 16 cm, axial length 1.5 times the radius) and glandular fraction by weight (0%, 14.3%, 25%, 50%, 75% and 100%) were implemented into the code. The validation of the code shows an excellent agreement both with previously published work and in terms of DgN and CDTI measurements. The implemented simulations show a dependence of the glandular dose estimate on the vertical dimension of the irradiated zone when a partial organ irradiation was implemented. Specific normalized coefficients for calculating the MGD to the whole breast or to the single irradiated slice were reported. PMID:26683710

  11. Computed tomography angiography in patients with active gastrointestinal bleeding.

    PubMed

    Reis, Fatima Regina Silva; Cardia, Patricia Prando; D'Ippolito, Giuseppe

    2015-01-01

    Gastrointestinal bleeding represents a common medical emergency, with considerable morbidity and mortality rates, and a prompt diagnosis is essential for a better prognosis. In such a context, endoscopy is the main diagnostic tool; however, in cases where the gastrointestinal hemorrhage is massive, the exact bleeding site might go undetected. In addition, a trained professional is not always present to perform the procedure. In an emergency setting, optical colonoscopy presents limitations connected with the absence of bowel preparation, so most of the small bowel cannot be assessed. Scintigraphy cannot accurately demonstrate the anatomic location of the bleeding and is not available at emergency settings. The use of capsule endoscopy is inappropriate in the acute setting, particularly in the emergency department at night, and is a highly expensive method. Digital angiography, despite its high sensitivity, is invasive, presents catheterization-related risks, in addition to its low availability at emergency settings. On the other hand, computed tomography angiography is fast, widely available and minimally invasive, emerging as a promising method in the diagnostic algorithm of these patients, being capable of determining the location and cause of bleeding with high accuracy. Based on a critical literature review and on their own experience, the authors propose a computed tomography angiography protocol to assess the patient with gastrointestinal bleeding.

  12. Forensic imaging of projectiles using cone-beam computed tomography.

    PubMed

    von See, Constantin; Bormann, Kai-Hendrik; Schumann, Paul; Goetz, Friedrich; Gellrich, Nils-Claudius; Rücker, Martin

    2009-09-10

    In patients with gunshot injuries, it is easy to detect a projectile within the body due to the high-density of the object, but artefacts make it difficult to obtain information about the deformation and the exact location of the projectile in surrounding tissues. Cone-beam computed tomography (CBCT) is a new radiological imaging modality that allows radio-opaque objects to be localised and assessed in three dimensions. The full potential of the use of CBCT in forensic medicine has not yet been explored. In this study, three different modern projectiles were fired into the heads of pig cadavers (n=6) under standardised conditions. Tissue destruction and the location of the projectiles were analysed separately using CBCT and multi-slice computed tomography (MDCT). The projectiles had the same kinetic energy but showed considerable differences in deformation behaviour. Within the study groups, tissue destruction was reproducible. CBCT is less severely affected by metallic artefacts than MDCT. Therefore CBCT is superior in visualising bone destruction in the immediate vicinity of the projectile and projectile deformation, whereas MDCT allows soft tissue to be evaluated in more detail. CBCT is an improved diagnostic tool for the evaluation of gunshot injuries. In particular, it is superior to MDCT in detecting structural hard-tissue damage in the immediate vicinity of high-density metal projectiles and in identifying the precise location of a projectile in the body.

  13. Assessment of metabolic bone diseases by quantitative computed tomography

    SciTech Connect

    Richardson, M.L.; Genant, H.K.; Cann, C.E.; Ettinger, B.; Gordan, G.S.; Kolb, F.O.; Reiser, U.J.

    1985-05-01

    Advances in the radiologic sciences have permitted the development of numerous noninvasive techniques for measuring the mineral content of bone, with varying degrees of precision, accuracy, and sensitivity. The techniques of standard radiography, radiogrammetry, photodensitometry, Compton scattering, neutron activation analysis, single and dual photon absorptiometry, and quantitative computed tomography (QCT) are described and reviewed in depth. Results from previous cross-sectional and longitudinal QCT investigations are given. They then describe a current investigation in which they studied 269 subjects, including 173 normal women, 34 patients with hyperparathyroidism, 24 patients with steroid- induced osteoporosis, and 38 men with idiopathic osteoporosis. Spinal quantitative computed tomography, radiogrammetry, and single photon absorptiometry were performed, and a spinal fracture index was calculated on all patients. The authors found a disproportionate loss of spinal trabecular mineral compared to appendicular mineral in the men with idiopathic osteoporosis and the patients with steroid-induced osteoporosis. They observed roughly equivalent mineral loss in both the appendicular and axial regions in the hyperparathyroid patients. The appendicular cortical measurements correlated moderately well with each other but less well with spinal trabecular QCT. The spinal fracture index correlated well with QCT and less well with the appendicular measurements.

  14. Use of cone beam computed tomography in periodontology

    PubMed Central

    Acar, Buket; Kamburoğlu, Kıvanç

    2014-01-01

    Diagnosis of periodontal disease mainly depends on clinical signs and symptoms. However, in the case of bone destruction, radiographs are valuable diagnostic tools as an adjunct to the clinical examination. Two dimensional periapical and panoramic radiographs are routinely used for diagnosing periodontal bone levels. In two dimensional imaging, evaluation of bone craters, lamina dura and periodontal bone level is limited by projection geometry and superpositions of adjacent anatomical structures. Those limitations of 2D radiographs can be eliminated by three-dimensional imaging techniques such as computed tomography. Cone beam computed tomography (CBCT) generates 3D volumetric images and is also commonly used in dentistry. All CBCT units provide axial, coronal and sagittal multi-planar reconstructed images without magnification. Also, panoramic images without distortion and magnification can be generated with curved planar reformation. CBCT displays 3D images that are necessary for the diagnosis of intra bony defects, furcation involvements and buccal/lingual bone destructions. CBCT applications provide obvious benefits in periodontics, however; it should be used only in correct indications considering the necessity and the potential hazards of the examination. PMID:24876918

  15. Computed tomography in evaluation of revision hip arthroplasty outcomes.

    PubMed

    Kochman, Andrzej; Morawska-Kochman, Monika; Guziński, Maciej; Drobniewski, Marek; Sibiński, Marcin; Synder, Marek

    2014-01-01

    Background. This study aimed to assess contact between Recon Shell reinforcement cages used in revision hip arthroplasty and the bony base. Radiographic examinations were performed with the use of multi-energy computed tomography. Material and methods. We tentatively assess the fixation of Burch-Schneider reinforcement cages (Recon Shell made by Aesculap company) implanted in 10 patients, using two methods of evaluation. An analysis of dual energy CT scans enabled us to assess contact between the reinforcement cages and the bony base. Results. The two methods of evaluation produced different results. The evaluation method based on the division of the acetabular component into a weight-bearing zone and a non-weight-bearing zone (accounting for screw fixation) showed lack of support in the weight-bearing zone in 6 out of 10 cases and direct contact with the implant bed in only one case. The assessment of contact at anchorage holes of reinforcement cages fixed at primary procedures revealed no such support in only one case and the presence of direct contact in 5 cases. There was no correlation between the radiological outcomes and clinical results based on the Harris Hip Score. Conclusions. 1. Multi-energy computed tomography (MARS) is useful in evaluating results of revision hip allo-plasty. 2. The introduction of new imaging techniques for the evaluation of revision procedures demonstrates a need for new, unified methods of outcome assessment adjusted to the characteristics of a particular procedure. PMID:25406920

  16. Fundamentals of cone beam computed tomography for a prosthodontist

    PubMed Central

    John, George Puthenpurayil; Joy, Tatu Elenjickal; Mathew, Justin; Kumar, Vinod R. B.

    2015-01-01

    Cone beam computed tomography (CBCT, also referred to as C-arm computed tomography [CT], cone beam volume CT, or flat panel CT) is a medical imaging technique of X-ray CT where the X-rays are divergent, forming a cone.[1] CBCT systems have been designed for imaging hard tissues of the maxillofacial region. CBCT is capable of providing sub-millimeter resolution in images of high diagnostic quality, with short scanning times (10–70 s) and radiation dosages reportedly up to 15–100 times lower than those of conventional CT scans. Increasing availability of this technology provides the dental clinician with an imaging modality capable of providing a three-dimensional representation of the maxillofacial skeleton with minimal distortion. The aim of this article is to sensitize the Prosthodontist to CBCT technology, provide an overview of currently available maxillofacial CBCT systems and review the specific application of various CBCT display modes to clinical Prosthodontic practice. A MEDLINE search for relevant articles in this specific area of interest was conducted. The selected articles were critically reviewed and the data acquired were systematically compiled. PMID:26929479

  17. Estimation of feline renal volume using computed tomography and ultrasound.

    PubMed

    Tyson, Reid; Logsdon, Stacy A; Werre, Stephen R; Daniel, Gregory B

    2013-01-01

    Renal volume estimation is an important parameter for clinical evaluation of kidneys and research applications. A time efficient, repeatable, and accurate method for volume estimation is required. The purpose of this study was to describe the accuracy of ultrasound and computed tomography (CT) for estimating feline renal volume. Standardized ultrasound and CT scans were acquired for kidneys of 12 cadaver cats, in situ. Ultrasound and CT multiplanar reconstructions were used to record renal length measurements that were then used to calculate volume using the prolate ellipsoid formula for volume estimation. In addition, CT studies were reconstructed at 1 mm, 5 mm, and 1 cm, and transferred to a workstation where the renal volume was calculated using the voxel count method (hand drawn regions of interest). The reference standard kidney volume was then determined ex vivo using water displacement with the Archimedes' principle. Ultrasound measurement of renal length accounted for approximately 87% of the variability in renal volume for the study population. The prolate ellipsoid formula exhibited proportional bias and underestimated renal volume by a median of 18.9%. Computed tomography volume estimates using the voxel count method with hand-traced regions of interest provided the most accurate results, with increasing accuracy for smaller voxel sizes in grossly normal kidneys (-10.1 to 0.6%). Findings from this study supported the use of CT and the voxel count method for estimating feline renal volume in future clinical and research studies. PMID:23278991

  18. Three-dimensional surface reconstruction for industrial computed tomography

    NASA Technical Reports Server (NTRS)

    Vannier, M. W.; Knapp, R. H.; Gayou, D. E.; Sammon, N. P.; Butterfield, R. L.; Larson, J. W.

    1985-01-01

    Modern high resolution medical computed tomography (CT) scanners can produce geometrically accurate sectional images of many types of industrial objects. Computer software has been developed to convert serial CT scans into a three-dimensional surface form, suitable for display on the scanner itself. This software, originally developed for imaging the skull, has been adapted for application to industrial CT scanning, where serial CT scans thrrough an object of interest may be reconstructed to demonstrate spatial relationships in three dimensions that cannot be easily understood using the original slices. The methods of three-dimensional reconstruction and solid modeling are reviewed, and reconstruction in three dimensions from CT scans through familiar objects is demonstrated.

  19. X-ray fluorescence computed tomography system for biomedical imaging

    NASA Astrophysics Data System (ADS)

    Enomoto, Toshiyuki; Sato, Eiichi; Abderyim, Purkhet; Matsukiyo, Hiroshi; Osawa, Akihiro; Watanabe, Manabu; Nagao, Jiro; Nomiya, Seiichiro; Hitomi, Keitro; Izumisawa, Mitsuru; Ogawa, Akira; Sato, Shigehiro

    2008-08-01

    An x-ray fluorescence (XRF) computed tomography (CT) system utilizing a cadmium telluride (CdTe) detector is described. The CT system is of the first generation type and consists of a cerium x-ray generator, a turn table, a translation stage, a two-stage controller, a CdTe spectrometer, a multichannel analyzer (MCA), a counter board (CB), and a personal computer (PC). When an object is exposed by the x-ray generator, iodine K-series fluorescences are produced and are detected from vertical direction to x-ray axis using the spectrometer. Fluorescent photons are selected out using the MCA and are counted by the PC via CB, and XRF CT is performed by repeating translation and rotation of an object.

  20. Boxers--computed tomography, EEG, and neurological evaluation

    SciTech Connect

    Ross, R.J.; Cole, M.; Thompson, J.S.; Kim, K.H.

    1983-01-14

    During the last three years, 40 ex-boxers were examined to determine the effects of boxing in regard to their neurological status and the computed tomographic (CT) appearance of the brain. Thirty-eight of these patients had a CT scan of the brain, and 24 had a complete neurological examination including an EEG. The results demonstrate a significant relationship between the number of bouts fought and CT changes indicating cerebral atrophy. Positive neurological findings were not significantly correlated with the number of bouts. Electroencephalographic abnormalities were significantly correlated with the number of bouts fought. Computed tomography and EEG of the brain should be considered as part of a regular neurological examination for active boxers and, if possible, before and after each match, to detect not only the effects of acute life-threatening brain trauma such as subdural hematomas and brain hemorrhages, but the more subtle and debilitating long-term changes of cerebral atrophy.

  1. Tracker Readout ASIC for Proton Computed Tomography Data Acquisition

    PubMed Central

    Johnson, Robert P.; DeWitt, Joel; Holcomb, Cole; Macafee, Scott; Sadrozinski, Hartmut F.-W.; Steinberg, David

    2014-01-01

    A unique CMOS chip has been designed to serve as the front-end of the tracking detector data acquisition system of a pre-clinical prototype scanner for proton computed tomography (pCT). The scanner is to be capable of measuring one to two million proton tracks per second, so the chip must be able to digitize the data and send it out rapidly while keeping the front-end amplifiers active at all times. One chip handles 64 consecutive channels, including logic for control, calibration, triggering, buffering, and zero suppression. It outputs a formatted cluster list for each trigger, and a set of field programmable gate arrays merges those lists from many chips to build the events to be sent to the data acquisition computer. The chip design has been fabricated, and subsequent tests have demonstrated that it meets all of its performance requirements, including excellent low-noise performance. PMID:24653525

  2. Longitudinal dynamics and tomography in the Tevatron

    SciTech Connect

    Stogin, J.; Sen, T.; Moore, R. S.

    2012-01-10

    Motivated by the desire to understand the longitudinal effects of beam-beam forces, we study the longitudinal dynamics of protons and anti-protons at injection and top energy in the Tevatron. Multi-turn data of the longitudinal profiles are captured to reveal information about frequencies of oscillation, and changes in the bunch distributions. Tomographic reconstruction is used to create phase space maps which are subsequently used to find the momentum distributions. Changes in these distributions for both proton and anti-proton beams are also followed through the operational cycle. We report too on the details of interesting dynamics and some unexpected findings.

  3. Computational fluid dynamics in cardiovascular disease.

    PubMed

    Lee, Byoung-Kwon

    2011-08-01

    Computational fluid dynamics (CFD) is a mechanical engineering field for analyzing fluid flow, heat transfer, and associated phenomena, using computer-based simulation. CFD is a widely adopted methodology for solving complex problems in many modern engineering fields. The merit of CFD is developing new and improved devices and system designs, and optimization is conducted on existing equipment through computational simulations, resulting in enhanced efficiency and lower operating costs. However, in the biomedical field, CFD is still emerging. The main reason why CFD in the biomedical field has lagged behind is the tremendous complexity of human body fluid behavior. Recently, CFD biomedical research is more accessible, because high performance hardware and software are easily available with advances in computer science. All CFD processes contain three main components to provide useful information, such as pre-processing, solving mathematical equations, and post-processing. Initial accurate geometric modeling and boundary conditions are essential to achieve adequate results. Medical imaging, such as ultrasound imaging, computed tomography, and magnetic resonance imaging can be used for modeling, and Doppler ultrasound, pressure wire, and non-invasive pressure measurements are used for flow velocity and pressure as a boundary condition. Many simulations and clinical results have been used to study congenital heart disease, heart failure, ventricle function, aortic disease, and carotid and intra-cranial cerebrovascular diseases. With decreasing hardware costs and rapid computing times, researchers and medical scientists may increasingly use this reliable CFD tool to deliver accurate results. A realistic, multidisciplinary approach is essential to accomplish these tasks. Indefinite collaborations between mechanical engineers and clinical and medical scientists are essential. CFD may be an important methodology to understand the pathophysiology of the development and

  4. Breast ultrasound computed tomography using waveform inversion with source encoding

    NASA Astrophysics Data System (ADS)

    Wang, Kun; Matthews, Thomas; Anis, Fatima; Li, Cuiping; Duric, Neb; Anastasio, Mark A.

    2015-03-01

    Ultrasound computed tomography (USCT) holds great promise for improving the detection and management of breast cancer. Because they are based on the acoustic wave equation, waveform inversion-based reconstruction methods can produce images that possess improved spatial resolution properties over those produced by ray-based methods. However, waveform inversion methods are computationally demanding and have not been applied widely in USCT breast imaging. In this work, source encoding concepts are employed to develop an accelerated USCT reconstruction method that circumvents the large computational burden of conventional waveform inversion methods. This method, referred to as the waveform inversion with source encoding (WISE) method, encodes the measurement data using a random encoding vector and determines an estimate of the speed-of-sound distribution by solving a stochastic optimization problem by use of a stochastic gradient descent algorithm. Computer-simulation studies are conducted to demonstrate the use of the WISE method. Using a single graphics processing unit card, each iteration can be completed within 25 seconds for a 128 × 128 mm2 reconstruction region. The results suggest that the WISE method maintains the high spatial resolution of waveform inversion methods while significantly reducing the computational burden.

  5. Evaluation of external beam hardening filters on image quality of computed tomography and single photon emission computed tomography/computed tomography.

    PubMed

    Rana, Nivedita; Rawat, Dinesh; Parmar, Madan; Dhawan, Devinder Kumar; Bhati, Ashok Kumar; Mittal, Bhagwant Rai

    2015-01-01

    This study was undertaken to evaluate the effect of external metal filters on the image quality of computed tomography (CT) and single photon emission computed tomography (SPECT)/CT images. Images of Jaszack phantom filled with water and containing iodine contrast filled syringes were acquired using CT (120 kV, 2.5 mA) component of SPECT/CT system, ensuring fixation of filter on X-ray collimator. Different thickness of filters of Al and Cu (1 mm, 2 mm, 3 mm, and 4 mm) and filter combinations Cu 1 mm, Cu 2 mm, Cu 3 mm each in combination with Al (1 mm, 2 mm, 3 mm, and 4 mm), respectively, were used. All image sets were visually analyzed for streak artifacts and contrast to noise ratio (CNR) was derived. Similar acquisition was done using Philips CT quality control (QC) phantom and CNR were calculated for its lexan, perspex, and teflon inserts. Attenuation corrected SPECT/CT images of Jaszack phantom filled with 444-555 MBq (12-15 mCi) of (99m)Tc were obtained by applying attenuation correction map generated by hardened X-ray beam for different filter combination, on SPECT data. Uniformity, root mean square (rms) and contrast were calculated in all image sets. Less streak artifacts at iodine water interface were observed in images acquired using external filters as compared to those without a filter. CNR for syringes, spheres, and inserts of Philips CT QC phantom was almost similar to Al 2 mm, Al 3 mm, and without the use of filters. CNR decreased with increasing copper thickness and other filter combinations. Uniformity and rms were lower, and value of contrast was higher for SPECT/CT images when CT was acquired with Al 2 mm and 3 mm filter than for images acquired without a filter. The study suggests that for Infinia Hawkeye 4, SPECT/CT system, Al 2 mm, and 3 mm are the optimum filters for improving image quality of SPECT/CT images of Jaszack or Philips CT QC phantom keeping other parameters of CT constant.

  6. Complementary roles of brain scintigraphy and computed tomography in multiple sclerosis

    SciTech Connect

    Moreno, A.J.; Brown, J.M.; Waller, S.F.; Lundy, M.M.; Brown, T.J.

    1983-12-01

    Cerebral computed tomography, with and without iodinated contrast, revealed the appearance and evolution of lesions in a 32-year-old man with multiple sclerosis. Two areas were enhanced with contrast, with one showing a mild mass effect and rim of enhancement. Serial brain scintigraphy using technetium-/sub 99m/ glucoheptonate, following the computed tomography, showed the appearance and regression of corresponding regions of increased uptake. Computed tomography one day prior to brain scintigraphy failed to demonstrate a region of increased accumulation of radiotracer. One week later, however, evidence of a corresponding unenhanced defect was noted on computed tomography. Clinical correlation is given additionally.

  7. Is there a role for the use of volumetric cone beam computed tomography in periodontics?

    PubMed

    du Bois, A H; Kardachi, B; Bartold, P M

    2012-03-01

    Volumetric computed cone beam tomography offers a number of significant advantages over conventional intraoral and extraoral panoramic radiography, as well as computed tomography. To date, periodontal diagnosis has relied heavily on the assessment of both intraoral radiographs and extraoral panoramic radiographs. With emerging technology in radiology there has been considerable interest in the role that volumetric cone beam computed tomography might play in periodontal diagnostics. This narrative reviews the current evidence and considers whether there is a role for volumetric cone beam computed tomography in periodontics.

  8. Special computer-aided computed tomography (CT) volume measurement and comparison method for pulmonary tuberculosis (TB)

    PubMed Central

    Liu, Jingming; Sun, Zhaogang; Xie, Ruming; Gao, Mengqiu; Li, Chuanyou

    2015-01-01

    The computed tomography (CT) manifestations in pulmonary tuberculosis (PTB) patients are complex and could not be quantitatively evaluated. We aimed to establish a new method to objectively measure the lung injury level in PTB by thoracic CT and make quantitative comparisons. In the retrospective study, a total of 360 adults were selected and divided into four groups according to their CT manifestations and medical history: Normal group, PTB group, PTB with diabetes mellitus (DM) group and Death caused by PTB group. Five additional patients who had continuous CT scans were chosen for preliminary longitudinal analysis. We established a new computer-aided CT volume measurement and comparison method for PTB patients (CACTV-PTB) which measured lung volume (LV) and thoracic volume (TV). RLT was calculated as the ratio of LV to TV and comparisons were performed among different groups. Standardized RLT (SRLT) was used in the longitudinal analysis among different patients. In the Normal group, LV and TV were positively correlated in linear regression (Ŷ=-0.5+0.46X, R2=0.796, P<0.01). RLT values were significantly different among four groups (Normal: 0.40±0.05, PTB: 0.37±0.08, PTB+DM: 0.34±0.06, Death: 0.23±0.04). The curves of SRLT value from different patients shared a same start point and could be compared directly. Utilizing the novel objective method CACTV-PTB makes it possible to compare the severity and dynamic change among different PTB patients. Our early experience also suggested that the lung injury is severer in the PTB+DM group than in the PTB group. PMID:26628995

  9. Synchrotron-based X-ray computed tomography during compression loading of cellular materials

    DOE PAGESBeta

    Cordes, Nikolaus L.; Henderson, Kevin; Stannard, Tyler; Williams, Jason J.; Xiao, Xianghui; Robinson, Mathew W. C.; Schaedler, Tobias A.; Chawla, Nikhilesh; Patterson, Brian M.

    2015-04-29

    Three-dimensional X-ray computed tomography (CT) of in situ dynamic processes provides internal snapshot images as a function of time. Tomograms are mathematically reconstructed from a series of radiographs taken in rapid succession as the specimen is rotated in small angular increments. In addition to spatial resolution, temporal resolution is important. Thus temporal resolution indicates how close together in time two distinct tomograms can be acquired. Tomograms taken in rapid succession allow detailed analyses of internal processes that cannot be obtained by other means. This article describes the state-of-the-art for such measurements acquired using synchrotron radiation as the X-ray source.

  10. Synchrotron-based X-ray computed tomography during compression loading of cellular materials

    SciTech Connect

    Cordes, Nikolaus L.; Henderson, Kevin; Stannard, Tyler; Williams, Jason J.; Xiao, Xianghui; Robinson, Mathew W. C.; Schaedler, Tobias A.; Chawla, Nikhilesh; Patterson, Brian M.

    2015-04-29

    Three-dimensional X-ray computed tomography (CT) of in situ dynamic processes provides internal snapshot images as a function of time. Tomograms are mathematically reconstructed from a series of radiographs taken in rapid succession as the specimen is rotated in small angular increments. In addition to spatial resolution, temporal resolution is important. Thus temporal resolution indicates how close together in time two distinct tomograms can be acquired. Tomograms taken in rapid succession allow detailed analyses of internal processes that cannot be obtained by other means. This article describes the state-of-the-art for such measurements acquired using synchrotron radiation as the X-ray source.

  11. Evaluation of dosimetry and image of very low-dose computed tomography attenuation correction for pediatric positron emission tomography/computed tomography: phantom study

    NASA Astrophysics Data System (ADS)

    Bahn, Y. K.; Park, H. H.; Lee, C. H.; Kim, H. S.; Lyu, K. Y.; Dong, K. R.; Chung, W. K.; Cho, J. H.

    2014-04-01

    In this study, phantom was used to evaluate attenuation correction computed tomography (CT) dose and image in case of pediatric positron emission tomography (PET)/CT scan. Three PET/CT scanners were used along with acryl phantom in the size for infant and ion-chamber dosimeter. The CT image acquisition conditions were changed from 10 to 20, 40, 80, 100 and 160 mA and from 80 to 100, 120 and 140 kVp, which aimed at evaluating penetrate dose and computed tomography dose indexvolume (CTDIvol) value. And NEMA PET Phantom™ was used to obtain PET image under the same CT conditions in order to evaluate each attenuation-corrected PET image based on standard uptake value (SUV) value and signal-to-noise ratio (SNR). In general, the penetrate dose was reduced by around 92% under the minimum CT conditions (80 kVp and 10 mA) with the decrease in CTDIvol value by around 88%, compared with the pediatric abdomen CT conditions (100 kVp and 100 mA). The PET image with its attenuation corrected according to each CT condition showed no change in SUV value and no influence on the SNR. In conclusion, if the minimum dose CT that is properly applied to body of pediatric patient is corrected for attenuation to ensure that the effective dose is reduced by around 90% or more compared with that for adult patient, this will be useful to reduce radiation exposure level.

  12. Radiolabeling, whole-body single photon emission computed tomography/computed tomography imaging, and pharmacokinetics of carbon nanohorns in mice

    PubMed Central

    Zhang, Minfang; Jasim, Dhifaf A; Ménard-Moyon, Cécilia; Nunes, Antonio; Iijima, Sumio; Bianco, Alberto; Yudasaka, Masako; Kostarelos, Kostas

    2016-01-01

    In this work, we report that the biodistribution and excretion of carbon nanohorns (CNHs) in mice are dependent on their size and functionalization. Small-sized CNHs (30–50 nm; S-CNHs) and large-sized CNHs (80–100 nm; L-CNHs) were chemically functionalized and radiolabeled with [111In]-diethylenetriaminepentaacetic acid and intravenously injected into mice. Their tissue distribution profiles at different time points were determined by single photon emission computed tomography/computed tomography. The results showed that the S-CNHs circulated longer in blood, while the L-CNHs accumulated faster in major organs like the liver and spleen. Small amounts of S-CNHs- and L-CNHs were excreted in urine within the first few hours postinjection, followed by excretion of smaller quantities within the next 48 hours in both urine and feces. The kinetics of excretion for S-CNHs were more rapid than for L-CNHs. Both S-CNH and L-CNH material accumulated mainly in the liver and spleen; however, S-CNH accumulation in the spleen was more prominent than in the liver. PMID:27524892

  13. Nondestructive assay using active and passive computed tomography

    SciTech Connect

    Roberson, G. P. ,LLNL

    1998-07-01

    The United States Department of Energy (DOE) has over 600,000 transuranic (TRU) waste drums temporarily stored at nearly 40 sites within the United States. Contents of these drums must be characterized before they are transported for permanent disposal. Traditional gamma-ray methods used to characterize nuclear waste introduce errors that are related to nonuniform measurement responses associated with unknown radioactive source and matrix material distributions. These errors can be reduced by application of tomographic techniques, that measure these distributions. The Lawrence Livermore National Laboratory (LLNL) has developed two tomographic-based waste assay systems. They use external radioactive sources and tomography-protocol to map the attenuation within a waste drum as a function of mono-energetic gamma-ray energy in waste containers. Passive tomography is used to localize and identify specific radioactive waste contents within the same waste containers. Reconstruction of the passive data via the active images allows internal waste radioactivities in a drum to be corrected for any overlying heterogeneous materials, thus yielding an absolute assay of the waste radioactivities. Calibration of both systems requires only point source measurements and are independent of matrix materials. The first system is housed at LLNL and was developed to study and validate research concepts. The second system is being developed with Bioimaging Research, Inc. (BIR) and is housed within a mobile waste characterization trailer. This system has traveled to three DOE facilities to demonstrate the active and passive computed tomography capability. Both systems have participated in and successfully passed the requirements of formal DOE-sponsored intercomparison studies. The systems have measured approximately 1 to 100 grains of plutonium within a variety of waste matrix materials. Laboratory and field results from these two systems over the past several years show that both systems

  14. Dynamic computing random access memory

    NASA Astrophysics Data System (ADS)

    Traversa, F. L.; Bonani, F.; Pershin, Y. V.; Di Ventra, M.

    2014-07-01

    The present von Neumann computing paradigm involves a significant amount of information transfer between a central processing unit and memory, with concomitant limitations in the actual execution speed. However, it has been recently argued that a different form of computation, dubbed memcomputing (Di Ventra and Pershin 2013 Nat. Phys. 9 200-2) and inspired by the operation of our brain, can resolve the intrinsic limitations of present day architectures by allowing for computing and storing of information on the same physical platform. Here we show a simple and practical realization of memcomputing that utilizes easy-to-build memcapacitive systems. We name this architecture dynamic computing random access memory (DCRAM). We show that DCRAM provides massively-parallel and polymorphic digital logic, namely it allows for different logic operations with the same architecture, by varying only the control signals. In addition, by taking into account realistic parameters, its energy expenditures can be as low as a few fJ per operation. DCRAM is fully compatible with CMOS technology, can be realized with current fabrication facilities, and therefore can really serve as an alternative to the present computing technology.

  15. Dynamic computing random access memory.

    PubMed

    Traversa, F L; Bonani, F; Pershin, Y V; Di Ventra, M

    2014-07-18

    The present von Neumann computing paradigm involves a significant amount of information transfer between a central processing unit and memory, with concomitant limitations in the actual execution speed. However, it has been recently argued that a different form of computation, dubbed memcomputing (Di Ventra and Pershin 2013 Nat. Phys. 9 200-2) and inspired by the operation of our brain, can resolve the intrinsic limitations of present day architectures by allowing for computing and storing of information on the same physical platform. Here we show a simple and practical realization of memcomputing that utilizes easy-to-build memcapacitive systems. We name this architecture dynamic computing random access memory (DCRAM). We show that DCRAM provides massively-parallel and polymorphic digital logic, namely it allows for different logic operations with the same architecture, by varying only the control signals. In addition, by taking into account realistic parameters, its energy expenditures can be as low as a few fJ per operation. DCRAM is fully compatible with CMOS technology, can be realized with current fabrication facilities, and therefore can really serve as an alternative to the present computing technology.

  16. Quantifying the debonding of inclusions through tomography and computational homology.

    SciTech Connect

    Lu, Wei-Yang; Johnson, George C.; Mota, Alejandro; Foulk, James W., III; Jin, Huiqing

    2010-09-01

    This report describes a Laboratory Directed Research and Development (LDRD) project to use of synchrotron-radiation computed tomography (SRCT) data to determine the conditions and mechanisms that lead to void nucleation in rolled alloys. The Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory (LBNL) has provided SRCT data of a few specimens of 7075-T7351 aluminum plate (widely used for aerospace applications) stretched to failure, loaded in directions perpendicular and parallel to the rolling direction. The resolution of SRCT data is 900nm, which allows elucidation of the mechanisms governing void growth and coalescence. This resolution is not fine enough, however, for nucleation. We propose the use statistics and image processing techniques to obtain sub-resolution scale information from these data, and thus determine where in the specimen and when during the loading program nucleation occurs and the mechanisms that lead to it. Quantitative analysis of the tomography data, however, leads to the conclusion that the reconstruction process compromises the information obtained from the scans. Alternate, more powerful reconstruction algorithms are needed to address this problem, but those fall beyond the scope of this project.

  17. Null space and resolution in dynamic computerized tomography

    NASA Astrophysics Data System (ADS)

    Hahn, Bernadette N.

    2016-02-01

    One major challenge in computerized tomography is to image objects which change during the data acquisition and hence lead to inconsistent data sets. Motion artefacts in the reconstructions can be reduced by applying specially adapted algorithms which take the dynamic behaviour into account. Within this article, we analyse the achievable resolution in the dynamic setting in case of two-dimensional affine deformations. To this end, we characterize the null space of the operator describing the dynamic case, using its singular value decomposition and a necessary dynamic consistency condition. This shows that independent of any reconstruction method, the specimen’s dynamics results in a loss of resolution compared to the stationary setting. Our theoretical results are illustrated at a numerical example.

  18. Pulmonary malignant melanoma with distant metastasis assessed by positron emission tomography-computed tomography.

    PubMed

    Kim, So Ri; Yoon, Ha-Yong; Jin, Gong Yong; Choe, Yeong Hun; Park, Seung Yong; Lee, Yong Chul

    2016-07-01

    Melanoma is a cutaneous malignant neoplasm of melanocytes. Primary malignant melanoma (MM) of the lung is very rare. Although previous reports have described the radiologic features of pulmonary MM, its rarity means that many factors are unknown. Thus, radiologic diagnosis is very difficult. Furthermore, there is little information regarding diagnostic application and/or the usefulness of [(18)F]-fluorine-2-fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography (FDG-PET-CT) for primary pulmonary MM. A 69-year-old patient with a productive cough lasting three weeks was admitted to our hospital. Chest CT showed a large single mass with a multi-lobulated margin and homogeneous enhancement in the right upper lobe, which was subsequently diagnosed as a primary pulmonary MM with multiple metastases. On PET-CT images, the pulmonary mass and multiple bone lesions showed very increased uptakes of FDG. Considering that pulmonary metastasis from a mucocutaneous melanoma is the main differential diagnosis of primary pulmonary MM, systemic assessment of the whole body is more important than for other types of lung malignancies. This report introduces PET-CT as a useful diagnostic modality for pulmonary MM, especially in cases of distant multiple metastases. PMID:27385996

  19. New approaches to gastric cancer staging: Beyond endoscopic ultrasound, computed tomography and positron emission tomography

    PubMed Central

    Yoon, Hyuk; Lee, Dong Ho

    2014-01-01

    Currently, there is no single gold standard modality for staging of gastric cancer and several methods have been used complementarily in the each clinical situation. To make up for the shortcomings of conventional modalities such as endoscopic ultrasound, computed tomography and 18F-fluoro-2-deoxyglucose positron emission tomography, numerous attempts with new approaches have been made for gastric cancer staging. For T staging, magnifying endoscopy with narrow-band was evaluated to differentiate mucosal cancer from submucosal cancer. Single/double contrast-enhanced ultrasound and diffusion-weighted magnetic resonance imaging were also tried to improve diagnostic accuracy of gastric cancer. For intraoperative staging with sentinel node mapping, indocyanine green infrared and fluorescence imaging was introduced. In addition, to detect micrometastasis, real-time reverse transcription-polymerase chain reaction system with multiple markers was studied. Staging laparoscopy using 5-aminolevulinic acid-mediated photodynamic diagnosis and percutaneous diagnostic peritoneal lavage were also evaluated. However, most studies reporting new staging methods is preliminary and further studies for validation in clinical practice are needed. In this mini-review, we discuss new progress in gastric cancer staging. Especially, we focus on new diagnostic approach to gastric cancer staging beyond the conventional modalities and briefly review the remarkable clinical results of the studies published over the past three years. PMID:25320516

  20. Role of positron emission tomography-computed tomography in non-small cell lung cancer

    PubMed Central

    Garg, Pankaj Kumar; Singh, Saurabh Kumar; Prakash, Gaurav; Jakhetiya, Ashish; Pandey, Durgatosh

    2016-01-01

    Lung cancer is the leading cause of cancer-related mortality worldwide. Non-small cell carcinoma and small cell carcinoma are the main histological subtypes and constitutes around 85% and 15% of all lung cancer respectively. Multimodality treatment plays a key role in the successful management of lung cancer depending upon the histological subtype, stage of disease, and performance status. Imaging modalities play an important role in the diagnosis and accurate staging of the disease, in assessing the response to neoadjuvant therapy, and in the follow-up of the patients. Last decade has witnessed voluminous upsurge in the use of positron emission tomography-computed tomography (PET-CT); role of PET-CT has widened exponentially in the management of lung cancer. The present article reviews the role of 18-fluoro-deoxyglucose PET-CT in the management of non small cell lung cancer with emphasis on staging of the disease and the assessment of response to neoadjuvant therapy based on available literature. PMID:27018223

  1. Stability in computed optical interferometric tomography (Part I): Stability requirements

    PubMed Central

    Shemonski, Nathan D.; Adie, Steven G.; Liu, Yuan-Zhi; South, Fredrick A.; Carney, P. Scott; Boppart, Stephen A.

    2014-01-01

    As imaging systems become more advanced and acquire data at faster rates, increasingly dynamic samples can be imaged without concern of motion artifacts. For optical interferometric techniques such as optical coherence tomography, it often follows that initially, only amplitude-based data are utilized due to unstable or unreliable phase measurements. As systems progress, stable phase maps can also be acquired, enabling more advanced, phase-dependent post-processing techniques. Here we report an investigation of the stability requirements for a class of phase-dependent post-processing techniques – numerical defocus and aberration correction with further extensions to techniques such as Doppler, phase-variance, and optical coherence elastography. Mathematical analyses and numerical simulations over a variety of instabilities are supported by experimental investigations. PMID:25321004

  2. Inspection of a Medieval Wood Sculpture Using Computer Tomography

    NASA Astrophysics Data System (ADS)

    Kapitany, K.; Somogyi, A.; Barsi, A.

    2016-06-01

    Computer tomography (CT) is an excellent technique for obtaining accurate 3D information about the human body. It allows to visualize the organs, bones and blood vessels, furthermore it enables to diagnose anomalies and diseases. Its spatial reconstruction capability supports other interesting applications, such as inspecting different, even valuable objects like ancient sculptures. Current paper presents a methodology of evaluating CT and video imagery through the example of investigating a wood Madonna with infant Jesus sculpture from the 14th century. The developed techniques extract the outer boundary of the statue, which has been triangulated to derive the surface model. The interior of the sculpture has also been revealed: the iron bolts and rivets as well as the woodworm holes can be mapped. By merging the interior and outer data (geometry and texture) interesting visualizations (perspective views, sections etc.) have been created.

  3. X- and {gamma}-ray computed tomography applications at LLNL

    SciTech Connect

    Roberson, G.P.; Martz, H.E.; Schneberk, D.J.; Azevedo, S.G.

    1993-04-01

    Members of the Nondestructive Evaluation (NDE) Section at the Lawrence Livermore National Laboratory (LLNL) have implemented the advanced three-dimensional imaging technique of x and {gamma}-ray computed tomography (CAT or CT) for industrial and scientific nondestructive evaluation. This technique provides internal and external views of materials, components, and assemblies nonintrusively. Our research and development includes building CT scanners as well as data preprocessing, image reconstruction, display and analysis algorithms. These capabilities have been applied for a variety of industrial and scientific NDE applications where objects can range in size from 1 mm{sup 3} to 1 m{sup 3}. Here we discuss the usefulness of Cr to evaluate: Ballistic target materials, high-explosives shape charges, missile nosetips, and reactor-fuel tubes.

  4. Cholesteatomas of the temporal bone: role of computed tomography

    SciTech Connect

    Johnson, D.W.; Voorhees, R.L.; Lufkin, R.B.; Canalis, R.

    1983-09-01

    Computed tomography (CT) of the temporal bone was performed in 64 patients thought to have a cholesteatoma of the middle ear. Twenty had not had surgery before, while 44 had been operated on; special consideration was given to 21 patients who were scanned immediately before a second operation and had confirmation of the CT findings. Inflammatory disease without cholesteatoma was characterized by absence of erosion of the otic capsule or ossicular chain. Sharply circumscribed cholesteatomas were easily diagnosed by CT. When they were combined with scarring, granulation tissue, or postsurgical changes, the resulting soft-tissue masses were indistinguishable, although cholesteatoma may be suspected if there is evidence of progressive bone erosion about the middle ear. CT can play a major role in postoperative follow-up by confirming that the ear is normal and demonstrating displacement of ossicular grafts or prostheses.

  5. Cone Beam Computed Tomography Evaluation of Inverted Mesiodentes.

    PubMed

    Al-Sehaibany, Fares S; Marzouk, Hazem M; Salama, Fouad S

    2016-01-01

    A mesiodens is the most common type of supernumerary teeth. The purpose of this report is to present a rare occurrence of non-syndromic impacted inverted mesiodentes in an 8.5-year-old boy who presented with a chief complaint of delayed eruption of his permanent maxillary left central incisor. Occlusal and panoramic radiographs, as well as cone beam computed tomography (CBCT) with a three-dimensional (3-D) reconstruction image, confirmed that one supernumerary tooth had perforated the nasal fossa floor and the other was in close approximation to the to the same site. Surgical removal of both mesiodentes was indicated. Radiographic evidence of complete healing was observed 12 months following surgical removal. The use of CBCT with a 3-D reconstruction image as a tool in diagnosis and evaluation of healing after surgical removal is recommended.

  6. A variable-resolution rotate-only computed tomography scanner.

    PubMed

    Hangartner, T N

    1994-10-01

    The Rotoscan is a computed tomography scanner that combines the advantages of variable geometric resolution and adjustable size of measurement diameter of translate-rotate scanners with the improved speed of rotate-only scanners. Because of the small number of only 26 detectors used for this scanner, a special data collection scheme of multiple rotations with interleaved detector positions was employed. In order to avoid angular data interpolation after reordering of the projections from the fan- to a parallel-beam geometry, the detectors were incrementally moved at a right angle to the centerline of the fan rather than rotated about the source. The measurement time of 40 s for one cross-section is comparable to that of second-generation systems. However, for longer measurement diameters, the measurement time for second-generation systems increases, whereas that of the Rotoscan remains constant.

  7. Computed tomography and magnetic resonance imaging in diagnosing hepatocellular carcinoma.

    PubMed

    Dalla Palma, L; Pozzi-Mucelli, R S

    1992-02-01

    The evaluation of hepatocellular carcinoma (HCC) is based upon ultrasonography (US) which has proved to have a high sensitivity and is also extremely useful in guiding the percutaneous needle biopsy. The main role of computed tomography (CT) and magnetic resonance imaging (MRI) is to supplement US in evaluating the extent of HCC. The Authors discuss the different techniques of examinations of the liver both for CT and MRI as far as the modalities of contrast enhancement, site of injection, and type of contrast agents are concerned. The differences between low field and high field magnets are also discussed. The main CT and MRI findings are illustrated, depending upon the technique of examination. Finally the role of these techniques is discussed. Based upon personal experience and the data in CT literature, and if performed with updated technology and intraarterial injection (lipiodol), CT is the method of choice in order to supplement US in the evaluation of HCC.

  8. Noninvasive hemoglobin oxygenation monitor and computed tomography by NIR spectrophotometry

    NASA Astrophysics Data System (ADS)

    Oda, Ichiro; Ito, Yasunobu; Eda, Hideo; Tamura, Tomomi; Takada, Michinosuke; Abumi, Rentaro; Nagai, Katumi; Nakagawa, Hachiro; Tamura, Masahide

    1991-05-01

    Using a near infrared (NIR) spectrophotometry, a compact instrument for monitoring the hemoglobin (Hb) oxygenation state in human brain was developed. Brian oxygen metabolism was non-invasively studied by simultaneous measurement of oxygenated Hb, deoxygnated Hb and total Hb content in rat and human head. After evaluating our method using anesthetized and artificially ventilated rats, this instrument was applied for clinical use, and was useful for the management of clinical patients. The same method was applied to develope the NIR computed tomography (CT). Human X-ray CT was modified for NIR-CT, and CT images were obtained using the back-projection (BP) method. NIR-CT could measure the oxygenation map of the tissues of anesthetized rats.

  9. Computed tomography of mesenteric involvement in fulminant pancreatitis

    SciTech Connect

    Jeffery, R.B.; Federle, M.P.; Laing, F.C.

    1983-04-01

    Although extension into the mesentery has been recognized as a frequent pathway of extrapancreatic spread in acute pancreatitis, it has received relatively little attention in the computed tomography (CT) literature. The medical records and CT scans of 55 patients with severe pancreatitis were reviewed in this study; of these patients, 19 (35%) had mesenteric abnormalities, which in 11 patients (20%) represented the most extensive extrapancreatic site of the most extensive extrapancreatic site of involvement. In fulminant pancreatitis, dissection along the mesentery is an important pathway for spread of pancreatic abscesses or phlegmons. Clinical correlation suggests that a combination of mesenteric with lesser sac and anterior pararenal space involvement is frequently associated with significant morbidity and mortality. Of the 19 patients with mesenteric involvement, two died and 14 (74%) required surgery for abscesses, pseudocysts, or, in one case, a colonic fistula. The CT features of the normal mesentery and CT criteria for diagnosing mesenteric inflammatory lesions are reviewed.

  10. Computed tomography and sonography of cavernous hemangioma of the liver

    SciTech Connect

    Itai, Y.; Ohtomo, K.; Araki, T.; Furui, S.; Iio, M.; Atomi, Y.

    1983-08-01

    Accuracy and limitations of computed tomography (CT) and sonography in the detection and diagnosis of cavernous hemangioma of the liver were analyzed in 39 cases. In 35 of 38 lesions examined by CT before and after bolus contrast enhancement, findings were dense contrast enhancement spreading in all directions on subsequent scans and/or density (other than capsule or septa) higher than normal hepatic parenchyma after 2 min. Lesions smaller than 1 cm were not detected. Misregistration in sequential scane prevented diagnosis of three of nine lesions smaller than 2 cm. Sonography revealed various patterns of mass, but in the smaller lesions, an extremely hyperechoic pattern was dominant. The contributions of CT and sonography depend on the size of the lesions.

  11. Initial results of finger imaging using photoacoustic computed tomography

    NASA Astrophysics Data System (ADS)

    van Es, Peter; Biswas, Samir K.; Moens, Hein J. Bernelot; Steenbergen, Wiendelt; Manohar, Srirang

    2014-06-01

    We present a photoacoustic computed tomography investigation on a healthy human finger, to image blood vessels with a focus on vascularity across the interphalangeal joints. The cross-sectional images were acquired using an imager specifically developed for this purpose. The images show rich detail of the digital blood vessels with diameters between 100 μm and 1.5 mm in various orientations and at various depths. Different vascular layers in the skin including the subpapillary plexus could also be visualized. Acoustic reflections on the finger bone of photoacoustic signals from skin were visible in sequential slice images along the finger except at the location of the joint gaps. Not unexpectedly, the healthy synovial membrane at the joint gaps was not detected due to its small size and normal vascularization. Future research will concentrate on studying digits afflicted with rheumatoid arthritis to detect the inflamed synovium with its heightened vascularization, whose characteristics are potential markers for disease activity.

  12. Spinal computed tomography scanning in the evaluation of metastatic disease

    SciTech Connect

    Redmond, J.; Spring, D.B.; Munderloh, S.H.; George, C.B.; Mansour, R.P.; Volk, S.A.

    1984-07-15

    Twenty patients with known metastatic cancer or high-risk primary cancer developed new lesions on Tc/sup 99m/ bone scans and had normal plain radiographs. Spinal computed tomography (CT) was performed on all new bone-scan-positive lesions in minimal examination time. Fifteen patients had extensive metastatic vertebral disease and received local radiotherapy. One patient with new metastatic vertebral disease on CT was treated only with chemotherapy and developed acute spinal cord compression. Four patients had discogenic disease or degenerative disease but no evidence of metastases. Radionuclide bone scans are more sensitive but less specific than plain radiographs in detecting early bone metastases. Early and accurate diagnosis of metastasis is particularly important in the axial spine to prevent epidural compression and fracture. Spinal CT is valuable for identifying the presence and extent of vertebral metastases, as well as the presence of benign disease in cancer patients.

  13. Software innovations in computed tomography for structural heart disease interventions.

    PubMed

    Hell, Michaela; Marwan, Mohamed; Gaede, Luise; Achenbach, Stephan

    2016-05-17

    Computed tomography (CT) provides high, isotropic spatial resolution and has become firmly established in pre-procedural imaging for structural heart disease interventions. It allows determination of the exact dimensions of the target structure, provides information regarding the access route and permits identification of fluoroscopic projection angles to provide optimal visualisation for device placement. Several software solutions are available and have been systematically evaluated in the context of transcatheter aortic valve implantation (TAVI). The use of software products to perform automated measurements can be useful, especially when the experience and expertise regarding evaluation of CT in the context of structural heart disease are limited. In scientific studies, software has been demonstrated to provide accurate support for annulus sizing and prosthesis selection, to aid in reliably identifying patients in whom a transfemoral access may be problematic, and to suggest suitable angulations for fluoroscopic imaging to achieve an orthogonal view onto the aortic valve during implantation. PMID:27174116

  14. Acute aortic syndromes: new insights from electrocardiographically gated computed tomography.

    PubMed

    Fleischmann, Dominik; Mitchell, R Scott; Miller, D Craig

    2008-01-01

    The development of retrospective electrocardiographic (ECG)-gating has proved to be a diagnostic and therapeutic boon for computed tomography (CT) imaging of patients with acute thoracic aortic diseases, such as aortic dissection/intramural hematoma (AD/IMH), penetrating atherosclerotic ulcer (APU), and ruptured/leaking aneurysm. The notorious pulsation motion artifacts in the ascending aorta confounding regular CT scanning can be eliminated, and involvement of the sinuses of Valsalva, the valve cusps, the aortic annulus, and the coronary arteries in aortic dissection can be clearly depicted or excluded. Motion-free images also allow reliable identification of the site of the primary intimal tear, the location, and extent of the intimomedial flap, and branch artery involvement. ECG-gated CTA also allows the detection of more subtle lesions and variants of aortic dissection, which may ultimately expand our understanding of these complex, life-threatening disorders.

  15. Performance of latex balloons for optical computed tomography

    NASA Astrophysics Data System (ADS)

    Jordan, K.; Walsh, A.; Peng, M.; Battista, J.

    2013-06-01

    Latex balloons filled with radiation sensitive hydrogels were evaluated as 3D dosimeters with optical computed tomography (CT) readout. Custom balloons, with less than 10 cm diameters, were made from latex sheets. Commercial, 13 cm diameter, clear balloons were investigated for larger volumes. Ferrous-xylenol orange and genipin gelatin gels selected for 1 and 30 Gy experiments, respectively. The thin stretched latex membrane allowed optical imaging to within 1 mm of the interior balloon edge. Reconstructed dose distributions demonstrated valid measurements to within 2 mm of the balloon surface. The rubber membrane provides a hybrid approach to deforming hydrogels. Uniform irradiation of a deformed gel resulted in a uniform dose being measured when scanned in the relaxed, initial balloon shape. The 13 cm diameter balloons were also effective and inexpensive vessels for hydrogels due to their high clarity, thinness and mechanical strength. Latex balloons represent an inexpensive method to obtain useful information from nearly the entire dosimeter volume.

  16. Quantifying Void Ratio Variation in Sand using Computed Tomography

    NASA Technical Reports Server (NTRS)

    Alshibli, Khalid A.; Batiste, Susan N.; Swanson, Roy A.; Sture, Stein; Costes, Nicholas C.; Lankton, Mark R.

    1999-01-01

    A series of displacement-controlled, conventional, drained axisymmetric (triaxial) experiments were conducted on dry Ottawa sand specimens at very low effective confining stresses in a microgravity environment aboard the Space Shuttle during the NASA STS-89 mission. Post-flight analysis included studying the internal fabric and failure patterns of these specimens using Computed Tomography (CT). The CT scans of three specimens subjected to different compression levels (uncompressed specimen, a specimen compressed to 3.3% nominal axial strain (epsilon(sub a)), and a specimen compressed to 25% epsilon(sub a)) are presented to investigate the evolution of instability patterns and to quantify void ratio variation. The progress of failure is described and discussed. Also, specimens' densities were calibrated using standard ASTM procedures and void ratio spatial variation was calculated and represented by contour maps and histograms. The CT technique demonstrated good ability to detect specimen inhomogeneities, localization patterns, and quantifying void ratio variation within sand specimens.

  17. Computed tomography dose optimisation in cystic fibrosis: A review

    PubMed Central

    Ferris, Helena; Twomey, Maria; Moloney, Fiachra; O’Neill, Siobhan B; Murphy, Kevin; O’Connor, Owen J; Maher, Michael

    2016-01-01

    Cystic fibrosis (CF) is the most common autosomal recessive disease of the Caucasian population worldwide, with respiratory disease remaining the most relevant source of morbidity and mortality. Computed tomography (CT) is frequently used for monitoring disease complications and progression. Over the last fifteen years there has been a six-fold increase in the use of CT, which has lead to a growing concern in relation to cumulative radiation exposure. The challenge to the medical profession is to identify dose reduction strategies that meet acceptable image quality, but fulfil the requirements of a diagnostic quality CT. Dose-optimisation, particularly in CT, is essential as it reduces the chances of patients receiving cumulative radiation doses in excess of 100 mSv, a dose deemed significant by the United Nations Scientific Committee on the Effects of Atomic Radiation. This review article explores the current trends in imaging in CF with particular emphasis on new developments in dose optimisation. PMID:27158420

  18. Fossa navicularis magna detection on cone-beam computed tomography

    PubMed Central

    Mupparapu, Mel

    2016-01-01

    Herein, we report and discuss the detection of fossa navicularis magna, a close radiographic anatomic variant of canalis basilaris medianus of the basiocciput, as an incidental finding in cone-beam computed tomography (CBCT) imaging. The CBCT data of the patients in question were referred for the evaluation of implant sites and to rule out pathology in the maxilla and mandible. CBCT analysis showed osseous, notch-like defects on the inferior aspect of the clivus in all four cases. The appearance of fossa navicularis magna varied among the cases. In some, it was completely within the basiocciput and mimicked a small rounded, corticated, lytic defect, whereas it appeared as a notch in others. Fossa navicularis magna is an anatomical variant that occurs on the inferior aspect of the clivus. The pertinent literature on the anatomical variations occurring in this region was reviewed. PMID:27051639

  19. Hematologic neoplasms: interpreting lung findings in chest computed tomography.

    PubMed

    Calvillo Batllés, P; Carreres Polo, J; Sanz Caballer, J; Salavert Lletí, M; Compte Torrero, L

    2015-01-01

    Lung disease is very common in patients with hematologic neoplasms and varies in function of the underlying disease and its treatment. Lung involvement is associated with high morbidity and mortality, so it requires early appropriate treatment. Chest computed tomography (CT) and the analysis of biologic specimens are the first line diagnostic tools in these patients, and sometimes invasive methods are necessary. Interpreting the images requires an analysis of the clinical context, which is often complex. Starting from the knowledge about the differential diagnosis of lung findings that radiologists acquire during training, this article aims to explain the key clinical and radiological aspects that make it possible to orient the diagnosis correctly and to understand the current role of CT in the treatment strategy for this group of patients.

  20. Brain perfusion: computed tomography and magnetic resonance techniques.

    PubMed

    Copen, William A; Lev, Michael H; Rapalino, Otto

    2016-01-01

    Cerebral perfusion imaging provides assessment of regional microvascular hemodynamics in the living brain, enabling in vivo measurement of a variety of different hemodynamic parameters. Perfusion imaging techniques that are used in the clinical setting usually rely upon X-ray computed tomography (CT) or magnetic resonance imaging (MRI). This chapter reviews CT- and MRI-based perfusion imaging techniques, with attention to image acquisition, clinically relevant aspects of image postprocessing, and fundamental differences between CT- and MRI-based techniques. Correlations with cerebrovascular physiology and potential clinical applications of perfusion imaging are reviewed, focusing upon the two major classes of neurologic disease in which perfusion imaging is most often performed: primary perfusion disorders (including ischemic stroke, transient ischemic attack, and reperfusion syndrome), and brain tumors.

  1. Correlative neuroanatomy of computed tomography and magnetic resonance imaging

    SciTech Connect

    Groot, J.

    1984-01-01

    Since the development of computed tomography (CT) more than a decade ago, still another form of imaging has become available that provides displays of normal and abnormal human structures. Magnetic resonance imaging is given complete coverage in this book. It describes both CT and MR anatomy that explains basic principles and the current status of imaging the brain and spine. The author uses three-dimensional concepts to provide the reader with a simple means to compare the main structures of the brain, skull and spine. Combining normal, gross neuroanatomic illustrations with CT and MR images of normal and abnormal conditions, the book provides diagnostic guidance. Drawings, photographs and radiologic images are used to help.

  2. Computed tomography of the tongue and floor of the mouth

    SciTech Connect

    Larsson, S.G.; Mancuso, A.; Hanafee, W.

    1982-05-01

    The anatomy of the tongue and floor of the mouth is readily discernible by computed tomography (CT) because of low-density fascial planes that outline the extrinsic musculature, lingual arteries, and hypoglossal nerves. Although the tongue is accessible to the examining finger, few patients can tolerate a detailed palpation. In planning for a partial glossectomy, CT scanning aids the surgeon who must be sure that the tumor is unilateral or that at least one lingual artery and one hypoglossal nerve can be preserved. The CT scans of 30 patients were reviewed for background anatomy. Pathologic changes are summarized for 16 extrinsic lesions and 11 intrinsic tumors. The status of the midline could be confirmed in 28 of the 30 patients. The fascial plane distortions by malignant intrinsic and extrinsic lesions are discussed.

  3. Computed tomography and magnetic resonance imaging comparisons in boxers

    SciTech Connect

    Jordan, B.D. ); Zimmerman, R.D. )

    1990-03-23

    The efficacy of computed tomography (CT) and magnetic resonance imaging (MRI) in identifying traumatic injuries of the brain was compared in a referred population of 21 amateur and professional boxers. Three boxers displayed CT scans with equivocal findings that were verified as artifacts by MRI. Eleven boxers had both CT and MRI scans with normal findings, and 7 boxers had both CT and MRI scans with abnormal findings. There were no instances where abnormalities demonstrated on CT scanning were not detected by MRI. However, some abnormalities detected on MRI were not detected on CT scans. These included a subdural hematoma, white-matter changes, and a focal contusion. Magnetic resonance imaging appears to be the neuroradiodiagnostic test of choice compared with CT.

  4. Bronnikov-aided correction for x-ray computed tomography.

    PubMed

    De Witte, Yoni; Boone, Matthieu; Vlassenbroeck, Jelle; Dierick, Manuel; Van Hoorebeke, Luc

    2009-04-01

    When a very-low-absorbing sample is scanned at an x-ray computed tomography setup with a microfocus x-ray tube and a high-resolution detector, the obtained projection images contain not only absorption contrast but also phase contrast. While images without a phase signal can be reconstructed very well, such mixed phase and absorption images give rise to severe artifacts in the reconstructed slices. A method is described that applies a correction to these mixed projections to remove the phase signal. These corrected images can then be processed using a standard filtered backprojection algorithm to obtain reconstructions with only few or no phase artifacts. This new method, which we call the Bronnikov-aided correction (BAC), can be used in a broad variety of applications and without much additional effort. It is tested on a biological and a pharmaceutical sample, and results are evaluated and discussed by comparing them with those of conventional reconstruction methods. PMID:19340263

  5. Multidetector computed tomography of temporomandibular joint: A road less travelled

    PubMed Central

    Pahwa, Shivani; Bhalla, Ashu Seith; Roychaudhary, Ajoy; Bhutia, Ongkila

    2015-01-01

    This article reviews the imaging anatomy of temporomandibular joint (TMJ), describes the technique of multi-detector computed tomography (MDCT) of the TMJ, and describes in detail various osseous pathologic afflictions affecting the joint. Traumatic injuries affecting the mandibular condyle are most common, followed by joint ankylosis as a sequel to arthritis. The congenital anomalies are less frequent, hemifacial microsomia being the most commonly encountered anomaly involving the TMJ. Neoplastic afflictions of TMJ are distinctly uncommon, osteochondroma being one of the most common lesions. MDCT enables comprehensive evaluation of osseous afflictions of TMJ, and is a valuable tool for surgical planning. Sagittal, coronal and 3D reformatted images well depict osseous TMJ lesions, and their relationship to adjacent structures. PMID:25984518

  6. Sequential computed tomography images demonstrating characteristic changes in fibrous dysplasia.

    PubMed

    Tokano, H; Sugimoto, T; Noguchi, Y; Kitamura, K

    2001-09-01

    Images of fibrous dysplasia (FD) on computed tomography (CT) or magnetic resonance imaging (MRI) vary depending on the relative proportions of the fibrous and osseous components. Based on analysis of the literature, Camilleri suggested that structural changes revealed by conventional radiography may be indicative of the progression of FD. Here we describe the case of a boy who presented at 12 years of age with monostotic FD located in the right maxilla. The lesion first appeared as a lamellar, "onion peel"-like structure on CT; then over the course of the next five years, the structure became what has been termed an "egg-shell lesion", before eventually assuming the form of a "ground-glass lesion". PMID:11564313

  7. The role of computed tomography in renal trauma

    SciTech Connect

    Federie, M.P.; Kaiser, J.A.; McAninch, J.W.; Jeffery, B.; Mall, J.C.

    1981-11-01

    Computed tomography (CT) and excretory urography were performed in 15 patients thought to have major renal trauma. In 4 cases, CT demonstrated extravasation of urine not detected by urography, and in all cases parenchymal injuries and extrarenal hematomas were depicted more accurately by CT. CT also proved to be superior to excretory urography in distinguishing relatively minor renal injuries (confusion, incomplete laceration, intrarenal hematoma, small extrarenal hematoma) from major or catastrophic injuries (complete laceration, fracture, shattered kidney), which significantly influenced the choice of surgical or medical therapy. CT also detected concurrent injuries of the spleen, liver, and/or pancrease in 4 cases. The authors feel that CT is valuable in the assessment of major renal trauma.

  8. Occult neuroblastoma presenting with opsomyoclonus: utility of computed tomography

    SciTech Connect

    Farrelly, C.; Daneman, A.; Chan, H.L.S.; Martin, D.J.

    1984-04-01

    The clinical and radiographic findings in 10 children with neuroblastoma presenting with opsomyoclonus are described and the literature is reviewed. Children with opsomyoclonus are often a diagnostic dilemma, as they may not have a palpable tumor or increased urinary catecholamines. Computed tomography (CT) is the most sensitive imaging method in locating tumors (100%) compared with plain radiography of the chest and abdomen (sensitivity 40%), excretory urography (50%), and /sup 99m/Tc radionuclide bone scans (50%). Since most neuroblastomas are solitary lesions that may arise in the adrenal glands or along the sympathetic chain from the neck down into the pelvis, the policy is to use plain radiography, sonography, and /sup 99m/Tc methylene diphosphonate (MDP) bone scans for the preliminary investigations of patients with opsomyoclonus. Body CT can then be tailored to suit the needs of the individual patients.

  9. Survey of patient dose in computed tomography in Syria 2009.

    PubMed

    Kharita, M H; Khazzam, S

    2010-09-01

    The radiation doses to patient in computed tomography (CT) in Syria have been investigated and compared with similar studies in different countries. This work surveyed 30 CT scanners from six different manufacturers distributed all over Syria. Some of the results in this paper were part of a project launched by the International Atomic Energy Agency in different regions of the world covering Asia, Africa and Eastern Europe. The dose quantities covered are CT dose index (CTDI(w)), dose-length product (DLP), effective dose (E) and collective dose. It was found that most CTDI(w) and DLP values were similar to the European reference levels and in line with the results of similar surveys in the world. The results were in good agreement with the UNSCEAR Report 2007. This study concluded a recommendation for national diagnostic reference level for the most common CT protocols in Syria. The results can be used as a base for future optimisation studies in the country.

  10. Recent developments in computed tomography for urolithiasis: diagnosis and characterization.

    PubMed

    Mc Laughlin, P D; Crush, L; Maher, M M; O'Connor, O J

    2012-01-01

    Objective. To critically evaluate the current literature in an effort to establish the current role of radiologic imaging, advances in computed tomography (CT) and standard film radiography in the diagnosis, and characterization of urinary tract calculi. Conclusion. CT has a valuable role when utilized prudently during surveillance of patients following endourological therapy. In this paper, we outline the basic principles relating to the effects of exposure to ionizing radiation as a result of CT scanning. We discuss the current developments in low-dose CT technology, which have resulted in significant reductions in CT radiation doses (to approximately one-third of what they were a decade ago) while preserving image quality. Finally, we will discuss an important recent development now commercially available on the latest generation of CT scanners, namely, dual energy imaging, which is showing promise in urinary tract imaging as a means of characterizing the composition of urinary tract calculi. PMID:22952473

  11. Acute aortic syndromes: new insights from electrocardiographically gated computed tomography.

    PubMed

    Fleischmann, Dominik; Mitchell, R Scott; Miller, D Craig

    2008-01-01

    The development of retrospective electrocardiographic (ECG)-gating has proved to be a diagnostic and therapeutic boon for computed tomography (CT) imaging of patients with acute thoracic aortic diseases, such as aortic dissection/intramural hematoma (AD/IMH), penetrating atherosclerotic ulcer (APU), and ruptured/leaking aneurysm. The notorious pulsation motion artifacts in the ascending aorta confounding regular CT scanning can be eliminated, and involvement of the sinuses of Valsalva, the valve cusps, the aortic annulus, and the coronary arteries in aortic dissection can be clearly depicted or excluded. Motion-free images also allow reliable identification of the site of the primary intimal tear, the location, and extent of the intimomedial flap, and branch artery involvement. ECG-gated CTA also allows the detection of more subtle lesions and variants of aortic dissection, which may ultimately expand our understanding of these complex, life-threatening disorders. PMID:19251175

  12. Fossa navicularis magna detection on cone-beam computed tomography.

    PubMed

    Syed, Ali Z; Mupparapu, Mel

    2016-03-01

    Herein, we report and discuss the detection of fossa navicularis magna, a close radiographic anatomic variant of canalis basilaris medianus of the basiocciput, as an incidental finding in cone-beam computed tomography (CBCT) imaging. The CBCT data of the patients in question were referred for the evaluation of implant sites and to rule out pathology in the maxilla and mandible. CBCT analysis showed osseous, notch-like defects on the inferior aspect of the clivus in all four cases. The appearance of fossa navicularis magna varied among the cases. In some, it was completely within the basiocciput and mimicked a small rounded, corticated, lytic defect, whereas it appeared as a notch in others. Fossa navicularis magna is an anatomical variant that occurs on the inferior aspect of the clivus. The pertinent literature on the anatomical variations occurring in this region was reviewed.

  13. Multidetector-row computed tomography in cerebral hydatid cyst

    PubMed Central

    Wani, Nisar A; Kosar, Tasleem L; Khan, Abdul Qayum; Ahmad, Sheikh Shahnawaz

    2010-01-01

    Intracranial localization is a rare manifestation of hydatid cyst disease (Echinococcosis). It comprises only 2% of cases of Echinococcosis infection even in endemic areas and is predominantly seen in children. Clinical manifestations resulting from raised intracranial tension are nonspecific. Imaging with computed tomography (CT) may suggest the diagnosis preoperatively with reasonable accuracy. Multidetector-row CT (MDCT) with its high resolution multiplanar reformations can demonstrate the relationship of the cyst with adjacent brain structures and thus help in planning surgery. This has a practical utility in places where magnetic resonance imaging is not available. We describe a case of cerebral hydatid cyst in a 13-year-old boy who was diagnosed with MDCT, which helped in planning its surgical removal. PMID:21808517

  14. An easily assembled laboratory exercise in computed tomography

    NASA Astrophysics Data System (ADS)

    Mylott, Elliot; Klepetka, Ryan; Dunlap, Justin C.; Widenhorn, Ralf

    2011-09-01

    In this paper, we present a laboratory activity in computed tomography (CT) primarily composed of a photogate and a rotary motion sensor that can be assembled quickly and partially automates data collection and analysis. We use an enclosure made with a light filter that is largely opaque in the visible spectrum but mostly transparent to the near IR light of the photogate (880 nm) to scan objects hidden from the human eye. This experiment effectively conveys how an image is formed during a CT scan and highlights the important physical and imaging concepts behind CT such as electromagnetic radiation, the interaction of light and matter, artefacts and windowing. Like our setup, previous undergraduate level laboratory activities which teach the basics of CT have also utilized light sources rather than x-rays; however, they required a more extensive setup and used devices not always easily found in undergraduate laboratories. Our setup is easily implemented with equipment found in many teaching laboratories.

  15. Data fusion in neutron and X-ray computed tomography

    SciTech Connect

    Schrapp, Michael J.; Goldammer, Matthias; Schulz, Michael; Issani, Siraj; Bhamidipati, Suryanarayana; Böni, Peter

    2014-10-28

    We present a fusion methodology between neutron and X-ray computed tomography (CT). On the one hand, the inspection by X-ray CT of a wide class of multimaterials in non-destructive testing applications suffers from limited information of object features. On the other hand, neutron imaging can provide complementary data in such a way that the combination of both data sets fully characterizes the object. In this contribution, a novel data fusion procedure, called Fusion Regularized Simultaneous Algebraic Reconstruction Technique, is developed where the X-ray reconstruction is modified to fulfill the available data from the imaging with neutrons. The experiments, which were obtained from an aluminum profile containing a steel screw, and attached carbon fiber plates demonstrate that the image quality in CT can be significantly improved when the proposed fusion method is used.

  16. Computed tomography of paraspinal musculature in ankylosing spondylitis.

    PubMed

    Gordon, T P; Sage, M R; Bertouch, J V; Brooks, P M

    1984-12-01

    Computed tomography (CT) was used to delineate the paraspinal musculature in 14 patients with ankylosing spondylitis (AS). Abnormal atrophy of the erector spinae muscles and multifidi was demonstrated in all 8 patients with total bony ankylosis of the spine, but was not present in those with isolated syndesmophyte formation, vertebral squaring alone or sacroiliac joint ankylosis with normal spinal radiographs. There was a significant positive correlation between a CT score of paravertebral muscle wasting and clinical parameters of disease duration and restriction of spinal mobility. Wasting and asymmetry of the psoas muscles was seen in 3 patients with unilateral hip joint involvement. These findings suggest that a relationship exists between decreased or absent spinal movement and atrophy of the paraspinal musculature in AS.

  17. Non-diffusing photochromic gel for optical computed tomography phantoms

    NASA Astrophysics Data System (ADS)

    Jordan, K.

    2013-06-01

    This study examines photochromic response in radiation sensitive hydrogels. Genipin, crosslinked, gelatin gel can support high resolution images because the chromophores do not diffuse. A low power, 633 nm He-Ne laser was used to write lines into the gels by a photobleaching reaction. Optical cone-beam computed tomography (CBCT) scans mapped the high resolution images in 3D with 0.25 mm voxel resolution. A straight line was written into a deformed gel and then readout in its relaxed, initial shape. The curved, photo-bleached line demonstrated deformable 3D dosimetry is possible with this system to the balloon edge. High resolution, photochromic images provide key information for characterizing optical CT scanners and 3D dosimeters. Many, ionizing radiation, dosimeter materials demonstrate either a photochromic or photothermal response, allowing this approach to be widely used in quantitative 3D scanning.

  18. Computer Tomography Imaging Findings of Abdominal Follicular Dendritic Cell Sarcoma

    PubMed Central

    Li, Jing; Geng, Zhi-Jun; Xie, Chuan-Miao; Zhang, Xin-Ke; Chen, Rui-Ying; Cai, Pei-Qiang; Lv, Xiao-Fei

    2016-01-01

    Abstract Follicular dendritic cell sarcoma (FDCS) is a neoplasm that arises from follicular dendritic cells. FDCSs originating in the abdomen are extremely rare. Clinically, they often mimic a wide variety of other abdominal tumors, and correct preoperative diagnosis is often a challenging task. To date, only scattered cases of abdominal FDCS have been reported and few data are available on their radiological features. Here we present the computer tomography imaging findings of 5 patients with surgically and pathologically demonstrated abdominal FDCS. An abdominal FDCS should be included in the differential diagnosis when single or multiple masses with relatively large size, well- or ill-defined borders, complex internal architecture with marked internal necrosis and/or focal calcification, and heterogeneous enhancement with “rapid wash-in and slow wash-out” or “progressive enhancement” enhancement patterns in the solid component are seen. PMID:26735543

  19. Three Dimensional Display Of Tumors Via Computed Tomography

    NASA Astrophysics Data System (ADS)

    Smathers, Ralph L.

    1985-09-01

    Computed tomography is widely utilized for the detection and staging of neoplasm. Typical chest, abdomen or pelvis CT scans may produce 10 to 20 transverse slices for each region. The mental reconstruction of the three dimensional anatomy from these transverse sections can be done by a physician who has had training in the analysis and interpretation of cross sectional anatomy and pathology. This mental reconstruction, however, may take years to develop into an efficient tool. With the 3-D reconstructions used in this study, diagnostic information concerning the location, shape and spread of tumor masses can be presented in a simple, intuitive 3-dimensional display. This technique has been found to be useful for improving communication between diagnostic radiologists and consulting physicians.

  20. Applications of dual energy computed tomography in abdominal imaging.

    PubMed

    Lestra, T; Mulé, S; Millet, I; Carsin-Vu, A; Taourel, P; Hoeffel, C

    2016-06-01

    Dual energy computed tomography (CT) is an imaging technique based on data acquisition at two different energy settings. Recent advances in CT have allowed data acquisition and almost simultaneously analysis of two spectra of X-rays at different energy levels resulting in novel developments in the field of abdominal imaging. This technique is widely used in cardiovascular imaging, especially for pulmonary embolism work-up but is now also increasingly developed in the field of abdominal imaging. With dual-energy CT it is possible to obtain virtual unenhanced images from monochromatic reconstructions as well as attenuation maps of different elements, thereby improving detection and characterization of a variety of renal, adrenal, hepatic and pancreatic abnormalities. Also, dual-energy CT can provide information regarding urinary calculi composition. This article reviews and illustrates the different applications of dual-energy CT in routine abdominal imaging.

  1. Novel clinical applications of dual energy computed tomography.

    PubMed

    Kraśnicki, Tomasz; Podgórski, Przemysław; Guziński, Maciej; Czarnecka, Anna; Tupikowski, Krzysztof; Garcarek, Jerzy; Marek Sąsiadek, Marek

    2012-01-01

    Dual energy CT (DECT) was conceived at the very beginning of the computed tomography era. However the first DECT scanner was developed in 2006. Nowadays there are three different types of DECT available: dual-source CT with 80(100) kVp and 140 kVp tubes (Siemens Medical Solution); dual-layer multi-detector scanner with acquisition 120 or 140kVp (Philips Healthcare); CT unit with one rapid kVp switching source and new detector based on gemstone scintillator materials (GE Healthcare). This article describes the physical background and principles of DECT imaging as well as applications of this innovative method in routine clinical practice (renal stone differentiation, pulmonary perfusion, neuroradiology and metallic implant imaging). The particular applications are illustrated by cases from author's material.

  2. Glasses for 3D ultrasound computer tomography: phase compensation

    NASA Astrophysics Data System (ADS)

    Zapf, M.; Hopp, T.; Ruiter, N. V.

    2016-03-01

    Ultrasound Computer Tomography (USCT), developed at KIT, is a promising new imaging system for breast cancer diagnosis, and was successfully tested in a pilot study. The 3D USCT II prototype consists of several hundreds of ultrasound (US) transducers on a semi-ellipsoidal aperture. Spherical waves are sequentially emitted by individual transducers and received in parallel by many transducers. Reflectivity volumes are reconstructed by synthetic aperture focusing (SAFT). However, straight forward SAFT imaging leads to blurred images due to system imperfections. We present an extension of a previously proposed approach to enhance the images. This approach includes additional a priori information and system characteristics. Now spatial phase compensation was included. The approach was evaluated with a simulation and clinical data sets. An increase in the image quality was observed and quantitatively measured by SNR and other metrics.

  3. Cone Beam Computed Tomography Evaluation of Inverted Mesiodentes.

    PubMed

    Al-Sehaibany, Fares S; Marzouk, Hazem M; Salama, Fouad S

    2016-01-01

    A mesiodens is the most common type of supernumerary teeth. The purpose of this report is to present a rare occurrence of non-syndromic impacted inverted mesiodentes in an 8.5-year-old boy who presented with a chief complaint of delayed eruption of his permanent maxillary left central incisor. Occlusal and panoramic radiographs, as well as cone beam computed tomography (CBCT) with a three-dimensional (3-D) reconstruction image, confirmed that one supernumerary tooth had perforated the nasal fossa floor and the other was in close approximation to the to the same site. Surgical removal of both mesiodentes was indicated. Radiographic evidence of complete healing was observed 12 months following surgical removal. The use of CBCT with a 3-D reconstruction image as a tool in diagnosis and evaluation of healing after surgical removal is recommended. PMID:27620520

  4. Software innovations in computed tomography for structural heart disease interventions.

    PubMed

    Hell, Michaela; Marwan, Mohamed; Gaede, Luise; Achenbach, Stephan

    2016-05-17

    Computed tomography (CT) provides high, isotropic spatial resolution and has become firmly established in pre-procedural imaging for structural heart disease interventions. It allows determination of the exact dimensions of the target structure, provides information regarding the access route and permits identification of fluoroscopic projection angles to provide optimal visualisation for device placement. Several software solutions are available and have been systematically evaluated in the context of transcatheter aortic valve implantation (TAVI). The use of software products to perform automated measurements can be useful, especially when the experience and expertise regarding evaluation of CT in the context of structural heart disease are limited. In scientific studies, software has been demonstrated to provide accurate support for annulus sizing and prosthesis selection, to aid in reliably identifying patients in whom a transfemoral access may be problematic, and to suggest suitable angulations for fluoroscopic imaging to achieve an orthogonal view onto the aortic valve during implantation.

  5. High-resolution computed tomography of the normal larynx

    SciTech Connect

    Silverman, P.M.; Korobkin, M.

    1983-05-01

    Computed tomography (CT) provides a unique method of evaluating abnormalities of the larynx by virture of its cross-sectional images. Several reports have demonstrated its utility in staging laryngeal carcinoma and defining the extent of injury in cases of laryngeal trauma. In order to appreciate subtle abnormalities of the larynx, a thorough understanding of the normal structures in this small anatomic area is crucial. Although previous studies have defined the normal CT anatomy of the larynx, many of the CT-anatomic correlations of the normal larynx used earlier-generation CT scanners with relatively poor resolution or were limited to transaxial images. High-resolution transaxial, coronal, and sagittal CT in vivo images are correlated with line drawings displaying normal laryngeal anatomy. The exquisite anatomic detail apparent in these images provides a sound basis for understanding subtle abnormalities in pathologic cases. (JMT)

  6. New identification possibilities with postmortem multislice computed tomography.

    PubMed

    Dedouit, Fabrice; Telmon, Norbert; Costagliola, Rémi; Otal, Philippe; Florence, Loubes Lacroix; Joffre, Francis; Rougé, Daniel

    2007-11-01

    Historically, radiographical identification has been done by comparing conventional antemortem and postmortem X-ray images. The advent of new technologies such as multislice computed tomography (MSCT) is making traditional antemortem examination increasingly less frequent. The authors present the results of MSCT study of 35 corpses, which demonstrated features potentially useful for identification purposes in ten cases. These features, which relate to abnormalities of postcranial bone as well as of the internal organs, are presented. Attempts were made to find any antemortem X-rays or MSCTs on the cases described to compare the two antemortem and postmortem images. Although antemortem imaging was recovered for only two cases (one case with a skeletal abnormality and one case with a visceral abnormality), it permitted for both cases the comparison of antemortem and postmortem MSCTs.

  7. High dynamic range optical projection tomography (HDR-OPT).

    PubMed

    Fei, Peng; Yu, Zhilong; Wang, Xu; Lu, Peter J; Fu, Yusi; He, Zi; Xiong, Jingwei; Huang, Yanyi

    2012-04-01

    Traditional optical projection tomography (OPT) acquires a single image at each rotation angle, thereby suffering from limitations in CCD dynamic range; this conventional usage cannot resolve features in samples with highly heterogeneous absorption, such as in small animals with organs of varying size. We present a novel technique, applying multiple-exposure high dynamic range (HDR) imaging to OPT, and demonstrate its ability to resolve fine details in zebrafish embryos, without complicated chemical clearing. We implement the tomographic reconstruction algorithm on the GPU, yielding a performance increase of two orders of magnitude. These features give our method potential application in high-throughput, high-resolution in vivo 3D imaging.

  8. Enhancement of photoacoustic tomography in the tissue with speed-of-sound variance using ultrasound computed tomography

    NASA Astrophysics Data System (ADS)

    Cheng, Ren-Xiang; Chao, Tao; Xiao-Jun, Liu

    2015-11-01

    The speed-of-sound variance will decrease the imaging quality of photoacoustic tomography in acoustically inhomogeneous tissue. In this study, ultrasound computed tomography is combined with photoacoustic tomography to enhance the photoacoustic tomography in this situation. The speed-of-sound information is recovered by ultrasound computed tomography. Then, an improved delay-and-sum method is used to reconstruct the image from the photoacoustic signals. The simulation results validate that the proposed method can obtain a better photoacoustic tomography than the conventional method when the speed-of-sound variance is increased. In addition, the influences of the speed-of-sound variance and the fan-angle on the image quality are quantitatively explored to optimize the image scheme. The proposed method has a good performance even when the speed-of-sound variance reaches 14.2%. Furthermore, an optimized fan angle is revealed, which can keep the good image quality with a low cost of hardware. This study has a potential value in extending the biomedical application of photoacoustic tomography. Projection supported by the National Basic Research Program of China (Grant No. 2012CB921504), the National Natural Science Foundation of China (Grant Nos. 11422439, 11274167, and 11274171), and the Specialized Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20120091110001).

  9. Computed Tomography Utilization in a Tertiary Care University Hospital

    PubMed Central

    Boone, John M.; Brunberg, James A.

    2009-01-01

    Purpose Improvements in computed tomography (CT) technology, with shorter scan times and better image quality, have contributed to an increase in the use of CT in the United States in recent years. This increased use has implications both for health policy and radiation risk assessment. The purpose of this study was to evaluate trends in CT utilization. Methods The CT performance records at a university-based, tertiary care, level 1 trauma center hospital were evaluated from 1998 through 2005. The hospital’s decision support infrastructure was used to track overall patient visits and stays. From these data sets, the age and sex dependency of CT utilization rates were evaluated for out-patients, in-patients, and emergency room patients. Results Out-patient utilization rates averaged over the age groups of 21–30 years old, 41–50 years, and 61–70 years were 20, 59, and 87 CT scans per 1000 out-patient visits, respectively. In-patient use for these same age group were 88, 148, and 162 CT scans per 1000 in-patient-days. CT utilization rates for emergency room (ER) patients were 705, 687, and 394 CT scans per 1000 ER patient visits, for the same 3 age groups. Male patients outnumbered female patients for both emergency room and in-patient CT utilization from the early teens through the mid-40s. Conclusions Overall use of computed tomography increased 27% from 2000 to 2004 for out-patient visits, and 48% over the same period for in-patients. CT utilization in our very high volume emergency room (ER), from 2000 to 2004, increased 131%. Part of the ER increased CT utilization may be due to the installation of two CT scanners near the ER. PMID:18242530

  10. Assessment of metabolic bone diseases by quantitative computed tomography

    NASA Technical Reports Server (NTRS)

    Richardson, M. L.; Genant, H. K.; Cann, C. E.; Ettinger, B.; Gordan, G. S.; Kolb, F. O.; Reiser, U. J.

    1985-01-01

    Advances in the radiologic sciences have permitted the development of numerous noninvasive techniques for measuring the mineral content of bone, with varying degrees of precision, accuracy, and sensitivity. The techniques of standard radiography, radiogrammetry, photodensitometry, Compton scattering, neutron activation analysis, single and dual photon absorptiometry, and quantitative computed tomography (QCT) are described and reviewed in depth. Results from previous cross-sectional and longitudinal QCT investigations are given. They then describe a current investigation in which they studied 269 subjects, including 173 normal women, 34 patients with hyperparathyroidism, 24 patients with steroid-induced osteoporosis, and 38 men with idiopathic osteoporosis. Spinal quantitative computed tomography, radiogrammetry, and single photon absorptiometry were performed, and a spinal fracture index was calculated on all patients. The authors found a disproportionate loss of spinal trabecular mineral compared to appendicular mineral in the men with idiopathic osteoporosis and the patients with steroid-induced osteoporosis. They observed roughly equivalent mineral loss in both the appendicular and axial regions in the hyperparathyroid patients. The appendicular cortical measurements correlated moderately well with each other but less well with spinal trabecular QCT. The spinal fracture index correlated well with QCT and less well with the appendicular measurements. Knowledge of appendicular cortical mineral status is important in its own right but is not a valid predictor of axial trabecular mineral status, which may be disproportionately decreased in certain diseases. Quantitative CT provides a reliable means of assessing the latter region of the skeleton, correlates well with the spinal fracture index (a semiquantitative measurement of end-organ failure), and offers the clinician a sensitive means of following the effects of therapy.

  11. Assessment of liver ablation using cone beam computed tomography

    PubMed Central

    Abdel-Rehim, Mohamed; Ronot, Maxime; Sibert, Annie; Vilgrain, Valérie

    2015-01-01

    AIM: To investigate the feasibility and accuracy of cone beam computed tomography (CBCT) in assessing the ablation zone after liver tumor ablation. METHODS: Twenty-three patients (17 men and 6 women, range: 45-85 years old, mean age 65 years) with malignant liver tumors underwent ultrasound-guided percutaneous tumor ablation [radiofrequency (n = 14), microwave (n = 9)] followed by intravenous contrast-enhanced CBCT. Baseline multidetector computed tomography (MDCT) and peri-procedural CBCT images were compared. CBCT image quality was assessed as poor, good, or excellent. Image fusion was performed to assess tumor coverage, and quality of fusion was rated as bad, good, or excellent. Ablation zone volumes on peri-procedural CBCT and post-procedural MDCT were compared using the non-parametric paired Wilcoxon t-test. RESULTS: Rate of primary ablation effectiveness was 100%. There were no complications related to ablation. Local tumor recurrence and new liver tumors were found 3 mo after initial treatment in one patient (4%). The ablation zone was identified in 21/23 (91.3%) patients on CBCT. The fusion of baseline MDCT and peri-procedural CBCT images was feasible in all patients and showed satisfactory tumor coverage (at least 5-mm margin). CBCT image quality was poor, good, and excellent in 2 (9%), 8 (35%), and 13 (56%), patients respectively. Registration quality between peri-procedural CBCT and post-procedural MDCT images was good to excellent in 17/23 (74%) patients. The median ablation volume on peri-procedural CBCT and post-procedural MDCT was 30 cm3 (range: 4-95 cm3) and 30 cm3 (range: 4-124 cm3), respectively (P-value > 0.2). There was a good correlation (r = 0.79) between the volumes of the two techniques. CONCLUSION: Contrast-enhanced CBCT after tumor ablation of the liver allows early assessment of the ablation zone. PMID:25593467

  12. Synergistic image reconstruction for hybrid ultrasound and photoacoustic computed tomography

    NASA Astrophysics Data System (ADS)

    Matthews, Thomas P.; Wang, Kun; Wang, Lihong V.; Anastasio, Mark A.

    2015-03-01

    Conventional photoacoustic computed tomography (PACT) image reconstruction methods assume that the object and surrounding medium are described by a constant speed-of-sound (SOS) value. In order to accurately recover fine structures, SOS heterogeneities should be quantified and compensated for during PACT reconstruction. To address this problem, several groups have proposed hybrid systems that combine PACT with ultrasound computed tomography (USCT). In such systems, a SOS map is reconstructed first via USCT. Consequently, this SOS map is employed to inform the PACT reconstruction method. Additionally, the SOS map can provide structural information regarding tissue, which is complementary to the functional information from the PACT image. We propose a paradigm shift in the way that images are reconstructed in hybrid PACT-USCT imaging. Inspired by our observation that information about the SOS distribution is encoded in PACT measurements, we propose to jointly reconstruct the absorbed optical energy density and SOS distributions from a combined set of USCT and PACT measurements, thereby reducing the two reconstruction problems into one. This innovative approach has several advantages over conventional approaches in which PACT and USCT images are reconstructed independently: (1) Variations in the SOS will automatically be accounted for, optimizing PACT image quality; (2) The reconstructed PACT and USCT images will possess minimal systematic artifacts because errors in the imaging models will be optimally balanced during the joint reconstruction; (3) Due to the exploitation of information regarding the SOS distribution in the full-view PACT data, our approach will permit high-resolution reconstruction of the SOS distribution from sparse array data.

  13. Photoacoustic computed tomography without accurate ultrasonic transducer responses

    NASA Astrophysics Data System (ADS)

    Sheng, Qiwei; Wang, Kun; Xia, Jun; Zhu, Liren; Wang, Lihong V.; Anastasio, Mark A.

    2015-03-01

    Conventional photoacoustic computed tomography (PACT) image reconstruction methods assume that the object and surrounding medium are described by a constant speed-of-sound (SOS) value. In order to accurately recover fine structures, SOS heterogeneities should be quantified and compensated for during PACT reconstruction. To address this problem, several groups have proposed hybrid systems that combine PACT with ultrasound computed tomography (USCT). In such systems, a SOS map is reconstructed first via USCT. Consequently, this SOS map is employed to inform the PACT reconstruction method. Additionally, the SOS map can provide structural information regarding tissue, which is complementary to the functional information from the PACT image. We propose a paradigm shift in the way that images are reconstructed in hybrid PACT-USCT imaging. Inspired by our observation that information about the SOS distribution is encoded in PACT measurements, we propose to jointly reconstruct the absorbed optical energy density and SOS distributions from a combined set of USCT and PACT measurements, thereby reducing the two reconstruction problems into one. This innovative approach has several advantages over conventional approaches in which PACT and USCT images are reconstructed independently: (1) Variations in the SOS will automatically be accounted for, optimizing PACT image quality; (2) The reconstructed PACT and USCT images will possess minimal systematic artifacts because errors in the imaging models will be optimally balanced during the joint reconstruction; (3) Due to the exploitation of information regarding the SOS distribution in the full-view PACT data, our approach will permit high-resolution reconstruction of the SOS distribution from sparse array data.

  14. Artifacts in computed tomography scanning of moving objects.

    PubMed

    Chen, George T Y; Kung, Jong H; Beaudette, Kevin P

    2004-01-01

    Target volumes in the thorax and abdomen are commonly computed tomography (CT) scanned during light respiration. In this article, we analyze the distortions introduced in helical scanning of moving objects. Objects of known geometry are placed on a moving sled and scanned in a multirow helical CT scanner. The motion of the sled approximates the magnitude and velocity of organ movement in patients during light respiration (amplitude 1 cm, period 4 seconds). Scans of the phantom are obtained in high speed mode at incremental phases of respiration, and the resulting images are compared with scans obtained when the phantom is static. Computer simulations of the scan process are also performed to interpret the results and extend the analysis to a greater range of parameters in scanning, motion, and object size. Resulting scans show that spherical test objects can be shortened by as much as 2 cm or twice the periodic motion amplitude. Object shape was significantly distorted, and the geometric center of the object was displaced by as much as +/-0.8 cm. Computer simulation results qualitatively agree with the experimentally observed phantom images. These simulations predict that the effect is clearly observable even if the amplitude is decreased to 0.5 cm. Implications of scanning moving objects on treatment planning are discussed.

  15. [RGSS-IDJ and its application to cranial computed tomography].

    PubMed

    Ikeda, M; Sakuma, S; Maruyama, K

    1989-04-25

    RGSS-IDJ is developed as the Japanese version of Report Generation Support System for Imaging Diagnosis (RGSS-ID), which is a developmental computer system that applies artificial intelligence (AI) methods to a reporting system. Now RGSS-IDJ supports the report generation of cranial computed tomography. A representation scheme called Generalized Finding Representation (GFR) is proposed, to bridge the gap between natural language expressions in the radiographic report and AI methods. GRF for RGSS-IDJ is the same as for RGSS-ID. The basic style for entering the findings on the radiograph is the dialogue system with the routine of query and answering it by selecting items with a mouse. This system encodes the input findings into the network expressions, which are represented as the list form in the LISP computer language. And, it reserves them into the knowledge data base. The content of the report will be able to be utilized for various analyses within AI paradigm. The final radiographic report is made in the natural Japanese language. PMID:2798047

  16. EEG, transmission computed tomography, and positron emission tomography with fluorodeoxyglucose /sup 18/F. Their use in adults with gliomas

    SciTech Connect

    Newmark, M.E.; Theodore, W.H.; Sato, S.; De La Paz, R.; Patronas, N.; Brooks, R.; Jabbari, B.; Di Chiro, G.

    1983-10-01

    We evaluated the relationship between findings from EEG, transmission computed tomography (CT), and positron emission tomography in 23 adults with gliomas. The cortical metabolic rate was suppressed in patients with and without focal slowing. Focal delta activity was not related to involvement of gray or white matter. Rhythmic delta activity and focal attenuation of background amplitude on EEG, however, were correlated with involvement of the thalamus.

  17. Retroperitoneal Endometriosis: A Possible Cause of False Positive Finding at 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

    PubMed Central

    Maffione, Anna Margherita; Panzavolta, Riccardo; Lisato, Laura Camilla; Ballotta, Maria; D'Isanto, Mariangela Zanforlini; Rubello, Domenico

    2015-01-01

    Endometriosis is a frequent and clinically relevant problem in young women. Laparoscopy is still the gold standard for the diagnosis of endometriosis, but frequently both morphologic and functional imaging techniques are involved in the diagnostic course before achieving a conclusive diagnosis. We present a case of a patient affected by infiltrating retroperitoneal endometriosis falsely interpreted as a malignant mass by contrast-enhanced magnetic resonance imaging and 18F-fluorodeoxyglucose positron emission tomography/computed tomography. PMID:26097425

  18. Grid-based representation and dynamic visualization of ionospheric tomography

    NASA Astrophysics Data System (ADS)

    He, L. M.; Yang, Y.; Su, C.; Yu, J. Q.; Yang, F.; Wu, L. X.

    2013-10-01

    The ionosphere is a dynamic system with complex structures. With the development of abundant global navigation satellite systems, the ionospheric electron density in different altitudes and its time variations can be obtained by ionospheric tomography technique using GNSS observations collected by the continuously operating GNSS tracking stations distributed over globe. However, it is difficult to represent and analyze global and local ionospheric electron density variations in three-dimensional (3D) space due to its complex structures. In this paper, we introduce a grid-based system to overcome this constraint. First, we give the principles, algorithms and procedures of GNSS-based ionospheric tomography technique. Then, the earth system spatial grid (ESSG) based on the spheroid degenerated octree grid (SDOG) is introduced in detail. Finally, more than 400 continuously operating GNSS receivers from the International GNSS Service are utilized to realize global ionospheric tomography, and then the ESSG is used to organize and express the tomography results in 4D, including 3 spatial dimensions and time.

  19. Time-Domain Terahertz Computed Axial Tomography NDE System

    NASA Technical Reports Server (NTRS)

    Zimdars, David

    2012-01-01

    NASA has identified the need for advanced non-destructive evaluation (NDE) methods to characterize aging and durability in aircraft materials to improve the safety of the nation's airline fleet. 3D THz tomography can play a major role in detection and characterization of flaws and degradation in aircraft materials, including Kevlar-based composites and Kevlar and Zylon fabric covers for soft-shell fan containment where aging and durability issues are critical. A prototype computed tomography (CT) time-domain (TD) THz imaging system has been used to generate 3D images of several test objects including a TUFI tile (a thermal protection system tile used on the Space Shuttle and possibly the Orion or similar capsules). This TUFI tile had simulated impact damage that was located and the depth of damage determined. The CT motion control gan try was designed and constructed, and then integrated with a T-Ray 4000 control unit and motion controller to create a complete CT TD-THz imaging system prototype. A data collection software script was developed that takes multiple z-axis slices in sequence and saves the data for batch processing. The data collection software was integrated with the ability to batch process the slice data with the CT TD-THz image reconstruction software. The time required to take a single CT slice was decreased from six minutes to approximately one minute by replacing the 320 ps, 100-Hz waveform acquisition system with an 80 ps, 1,000-Hz waveform acquisition system. The TD-THZ computed tomography system was built from pre-existing commercial off-the-shelf subsystems. A CT motion control gantry was constructed from COTS components that can handle larger samples. The motion control gantry allows inspection of sample sizes of up to approximately one cubic foot (.0.03 cubic meters). The system reduced to practice a CT-TDTHz system incorporating a COTS 80- ps/l-kHz waveform scanner. The incorporation of this scanner in the system allows acquisition of 3D

  20. Just Scan It!-Weapon Reconstruction in Computed Tomography on Historical and Current Swiss Military Guns.

    PubMed

    Franckenberg, Sabine; Binder, Thomas; Bolliger, Stephan; Thali, Michael J; Ross, Steffen G

    2016-09-01

    Cross-sectional imaging, such as computed tomography, has been increasingly implemented in both historic and recent postmortem forensic investigations. It aids in determining cause and manner of death as well as in correlating injuries to possible weapons. This study illuminates the feasibility of reconstructing guns in computed tomography and gives a distinct overview of historic and recent Swiss Army guns. PMID:27454744

  1. Just Scan It!-Weapon Reconstruction in Computed Tomography on Historical and Current Swiss Military Guns.

    PubMed

    Franckenberg, Sabine; Binder, Thomas; Bolliger, Stephan; Thali, Michael J; Ross, Steffen G

    2016-09-01

    Cross-sectional imaging, such as computed tomography, has been increasingly implemented in both historic and recent postmortem forensic investigations. It aids in determining cause and manner of death as well as in correlating injuries to possible weapons. This study illuminates the feasibility of reconstructing guns in computed tomography and gives a distinct overview of historic and recent Swiss Army guns.

  2. [Potential of abdominal computed tomography and ultrasonography for the complex diagnosis of early gastric cancer].

    PubMed

    Gorshkov, A N

    2003-01-01

    The potential of computed tomography and ultrasonography in making complex diagnosis of "small forms" of early gastric cancer was demonstrated by evaluation of the data on examination of 116 patients and the pivotal role of the extent of intramural invasion was established. The semiotics of computed tomography and ultrasonography for intramural invasion and the sequence of X-ray and endoscopic procedures were developed.

  3. Perfusion computer tomography: imaging and clinical validation in acute ischaemic stroke.

    PubMed

    Bivard, Andrew; Spratt, Neil; Levi, Christopher; Parsons, Mark

    2011-11-01

    Computed tomography perfusion imaging in acute stroke requires further validation. We aimed to establish the optimal computed tomography perfusion parameters defining the infarct core and critically hypoperfused tissue. Sub-6-h computed tomography perfusion and 24-h magnetic resonance imaging were analysed from 314 consecutive patients with ischaemic stroke. Diffusion-weighted imaging lesion volume at 24 h was used to define the extent of critically hypoperfused tissue (in patients without reperfusion between acute and 24-h time points), and infarct core (in patients with major reperfusion at 24 h). Pixel-based analysis of co-registered computed tomography perfusion and diffusion-weighted imaging was then used to define the optimum computed tomography perfusion thresholds for critically hypoperfused at-risk tissue and infarct core. These optimized acute computed tomography perfusion threshold-based lesion volumes were then compared with 24-h diffusion-weighted imaging infarct volume, as well as 24-h and 90-day clinical outcomes for validation. Relative delay time >2 s was the most accurate computed tomography perfusion threshold in predicting the extent of critically hypoperfused tissue with both receiver operating curve analysis (area under curve 0.86), and the volumetric validation (mean difference between computed tomography perfusion and 24-h diffusion-weighted imaging lesions = 2 cm(2), 95% confidence interval 0.5-3.2 cm(2)). Cerebral blood flow <40% (of contralateral) within the relative delay time >2 s perfusion lesion was the most accurate computed tomography perfusion threshold at defining infarct core with both receiver operating characteristic analysis (area under curve = 0.85) and the volumetric validation. Using these thresholds, the extent of computed tomography perfusion mismatch tissue (the volume of 'at-risk' tissue between the critically hypoperfused and core thresholds) salvaged from infarction correlated with clinical improvement at 24 h (R(2

  4. Dynamics of quantum tomography in an open system

    NASA Astrophysics Data System (ADS)

    Uchiyama, Chikako

    2015-06-01

    In this study, we provide a way to describe the dynamics of quantum tomography in an open system with a generalized master equation, considering a case where the relevant system under tomographic measurement is influenced by the environment. We apply this to spin tomography because such situations typically occur in μSR (muon spin rotation/relaxation/resonance) experiments where microscopic features of the material are investigated by injecting muons as probes. As a typical example to describe the interaction between muons and a sample material, we use a spin-boson model where the relevant spin interacts with a bosonic environment. We describe the dynamics of a spin tomogram using a time-convolutionless type of generalized master equation that enables us to describe short time scales and/or low-temperature regions. Through numerical evaluation for the case of Ohmic spectral density with an exponential cutoff, a clear interdependency is found between the time evolution of elements of the density operator and a spin tomogram. The formulation in this paper may provide important fundamental information for the analysis of results from, for example, μSR experiments on short time scales and/or in low-temperature regions using spin tomography.

  5. Change in guardians’ preference for computed tomography after explanation by emergency physicians in pediatric head injury

    PubMed Central

    Jeong, Jin Hee; Lee, Jin Hee; Kim, Kyuseok; Rhee, Joong Eui; Kim, Tae Yun; Jo, You Hwan; Kim, Yu Jin; Lee, Jae Hyuk; Kang, Changwoo; Lee, Soo Hoon; Kim, Joonghee; Park, Chan Jong; Kwon, Hyuksool

    2015-01-01

    Objective Head injury in children is a common problem presenting to emergency departments, and cranial computed tomography scanning is the diagnostic standard for these patients. Several decision rules are used to determine whether computed tomography scans should be used; however, the use of computed tomography scans is often influenced by guardians’ preference toward the scans. The objective of this study was to identify changes in guardian preference for minor head injuries after receiving an explanation based on the institutional clinical practice guideline. Methods A survey was conducted between July 2010 and June 2012. Patients younger than 16 years with a Glasgow Coma Scale score of 15 after a head injury and their guardians were included. Pre- and post-explanation questionnaires were given to guardians to assess their preference for computed tomography scans and factors related to the degree of preference. Treating physicians explained the risks and benefits of cranial computed tomography scanning using the institutional clinical practice guideline. Guardian preference for a computed tomography scan was examined using a 100-mm visual analog scale. Results In total, 208 patients and their guardians were included in this survey. Guardian preference for computed tomography scans was significantly reduced after explanation (46.7 vs. 17.4, P<0.01). Pre-explanation preference and the strength of the physician recommendation to get a computed tomography were the most important factors affecting pre- and post-explanation changes in preferences. Conclusion Explanation of the risks and benefits of cranial computed tomography scans using the institutional clinical practice guideline may significantly reduce guardian preference for computed tomography scans. PMID:27752602

  6. The expanding influence of computed tomography and the application of computer-guided implantology.

    PubMed

    Mandelaris, George A; Rosenfeld, Alan L

    2008-06-01

    Implant dentistry is changing. There are currently two types of computed tomogrophy (CT) scanners--multi-slice and cone beam--available to the dental professional. Computed tomography allows for proactive planning among the entire implant team and with the patient, a concept referred to as "collaborative accountability" In addition, CT surgical guidance that enhances accuracy and precision is available to ensure prosthetic outcomes. A logical and progressive approach is outlined that allows each clinician to assess how to embrace this paradigm shift in his or her clinical practice, and provide better and safer patient care.

  7. Computational Fluid Dynamics Analysis of Thoracic Aortic Dissection

    NASA Astrophysics Data System (ADS)

    Tang, Yik; Fan, Yi; Cheng, Stephen; Chow, Kwok

    2011-11-01

    Thoracic Aortic Dissection (TAD) is a cardiovascular disease with high mortality. An aortic dissection is formed when blood infiltrates the layers of the vascular wall, and a new artificial channel, the false lumen, is created. The expansion of the blood vessel due to the weakened wall enhances the risk of rupture. Computational fluid dynamics analysis is performed to study the hemodynamics of this pathological condition. Both idealized geometry and realistic patient configurations from computed tomography (CT) images are investigated. Physiological boundary conditions from in vivo measurements are employed. Flow configuration and biomechanical forces are studied. Quantitative analysis allows clinicians to assess the risk of rupture in making decision regarding surgical intervention.

  8. Compensation for air voids in photoacoustic computed tomography image reconstruction

    NASA Astrophysics Data System (ADS)

    Matthews, Thomas P.; Li, Lei; Wang, Lihong V.; Anastasio, Mark A.

    2016-03-01

    Most image reconstruction methods in photoacoustic computed tomography (PACT) assume that the acoustic properties of the object and the surrounding medium are homogeneous. This can lead to strong artifacts in the reconstructed images when there are significant variations in sound speed or density. Air voids represent a particular challenge due to the severity of the differences between the acoustic properties of air and water. In whole-body small animal imaging, the presence of air voids in the lungs, stomach, and gastrointestinal system can limit image quality over large regions of the object. Iterative reconstruction methods based on the photoacoustic wave equation can account for these acoustic variations, leading to improved resolution, improved contrast, and a reduction in the number of imaging artifacts. However, the strong acoustic heterogeneities can lead to instability or errors in the numerical wave solver. Here, the impact of air voids on PACT image reconstruction is investigated, and procedures for their compensation are proposed. The contributions of sound speed and density variations to the numerical stability of the wave solver are considered, and a novel approach for mitigating the impact of air voids while reducing the computational burden of image reconstruction is identified. These results are verified by application to an experimental phantom.

  9. X-ray computed tomography for casting development

    NASA Astrophysics Data System (ADS)

    Georgeson, Gary E.; Crews, Alan R.; Bossi, Richard H.

    1992-09-01

    Computed tomography (CT) has been used to evaluate specific sand casting product examples for technical and economic benefits. The representative results are applicable to other casting technologies as well. CT has been shown to be cost effective in the development of new castings. The areas which would benefit include internal dimensional measurements (eliminating destructive sectioning), specific region inspections, flaw characterization in critical regions (to allow passing or informed repair of castings), and geometric acquisition for CAD/CAM. The quantitative capability of CT allows an engineering evaluation of castings based upon a correlation with performance. This quantitative measurement capability has also been used to measure the benefit of hot isostatic pressing in casting production. CT is also cost effective for engineering design and analysis by providing rapid geometry acquisition for input to computer aided design systems. This is particularly beneficial for components that do not have existing drawings or cannot be adequately defined until they are made for any reason. Presently CT can serve as an engineering aid to casting manufacturing. In order for CT evaluation to become routine in foundry applications, however, casting designers need to call it out as a measurement technique in the original casting design drawings, specifications on the application of CT must be written, contracts must include CT evaluation as a means for accepting casting quality, and lower cost CT systems must be available.

  10. Mathematical model of single-photon emission computed tomography

    SciTech Connect

    Clough, A.V.

    1986-01-01

    Single-photon emission computed tomography (SPECT) is a nuclear-medicine imaging technique that has been shown to provide clinically useful images of radionuclide distributions within the body. The problem of quantitative determination of tomographic activity images from a projection data set leads to a mathematical inverse problem which is formulated as an integral equation. The solution of this problem then depends on an accurate mathematical model as well as a reliable and efficient inversion algorithm. The effects of attenuation and Compton scatter within the body have been incorporated into the model in the hopes of providing a more physically realistic mathematical model. The attenuated Radon transform is the mathematical basis of SPECT. In this work, the case of constant attenuation is reviewed and a new proof of the Tretiak-Metz algorithm is presented. A space-domain version of the inverse attenuated Radon transform is derived. A special case of this transform that is applicable when the object is rotationally symmetric, and attenuated Abel transform is derived, and its inverse is found. A numerical algorithm for the implementation of the inverse attenuated Radon transform with constant attenuation is described and computer simulations are performed to demonstrate the results of the inversion procedure. With the use of the single-scatter approximation and an energy-windowed detector, the effects of Compton scatter are incorporated into the model. The data are then taken to be the sum of primary photons and single-scattered photons.

  11. Inexpensive computed tomography for remote areas via teleradiology

    NASA Astrophysics Data System (ADS)

    Gordon, Richard

    1990-06-01

    While x-ray computed tomography (CT) is falling in price it is still beyond the means of most primary and secondary health care centres in the world. I would like to show how if a teleradiology system is installed there is a good prospect for also being able to install a simple but diagnostically effective CT system. This can be based on film used either as a one or two dimensional detector. 1. CT SYSTEMS The major components of a CT system are: 1) health care worker(s) who can decide which part of a patient needs to be imaged 2) an x-ray transparent bed on which a patient can be made comfortable positioned and restrained as necessary 3) an x-ray source mounted on a gantry 4) an x-ray detector mounted on the gantry 5) a digitizer for the x-ray signal 6) a computer to receive the signal 7) an algorithm that calculates the reconstructed CT image 8) a halftone or color display monitor 9) a radiologist who can interpret the images 10) communication from the radiologist to the health care worker(s). 2. BENEFITS OF CT VIA TELERADIOLOGY I would like to proceed on the premise that a teleradiology system could be placed between steps 6 and 7. This has the following benefits: a) Radiologists who are relatively scarce and generally located in urban tertiary care centres could serve people in remote areas

  12. Pediatric Computed Tomography. Radiation Dose in Abdominal Studies

    NASA Astrophysics Data System (ADS)

    López, X.; Ruiz-Trejo, C.; Buenfil, A. E.; Gamboa-deBuen, I.; Dies, P.

    2008-08-01

    Computed tomography is one of the most popular medical imaging modalities used in the last years. However, because is one of the techniques that delivered a considerable radiation dose, precautions should be taken into account. Pediatric patients are more radiosensitive than adults, and the probability that no desirable biological effects can occur is greater. To this, also it adds the probability that they will need more radiological studies in the future. The work consisted in determining the received dose by the pediatric patients undergoing abdominal studies in a multislice computed tomograph, according to the dosimetric quantities established by a Code of Practice published by the International Atomic Energy Agency; using a ionization chamber and a phantom that simulates the abdomen of a pediatric patient. The weighted air kerma index (Cw) was 14.3±0.4 mGy, this value is lower than the published by the American College of Radiology, 25 mGy. The multiple scan average dose (MSAD), which is a quantity established by the NOM-229-SSA1-2002 was determined, finding a value of 14.2±0.1 mGy, it is also below the value established, 25 mGy for an adult study.

  13. Pediatric Computed Tomography. Radiation Dose in Abdominal Studies

    SciTech Connect

    Lopez, X.; Ruiz-Trejo, C.; Buenfil, A. E.; Gamboa-deBuen, I.; Dies, P

    2008-08-11

    Computed tomography is one of the most popular medical imaging modalities used in the last years. However, because is one of the techniques that delivered a considerable radiation dose, precautions should be taken into account. Pediatric patients are more radiosensitive than adults, and the probability that no desirable biological effects can occur is greater. To this, also it adds the probability that they will need more radiological studies in the future. The work consisted in determining the received dose by the pediatric patients undergoing abdominal studies in a multislice computed tomograph, according to the dosimetric quantities established by a Code of Practice published by the International Atomic Energy Agency; using a ionization chamber and a phantom that simulates the abdomen of a pediatric patient. The weighted air kerma index (C{sub w}) was 14.3{+-}0.4 mGy, this value is lower than the published by the American College of Radiology, 25 mGy. The multiple scan average dose (MSAD), which is a quantity established by the NOM-229-SSA1-2002 was determined, finding a value of 14.2{+-}0.1 mGy, it is also below the value established, 25 mGy for an adult study.

  14. High-resolution computed tomography reconstructions of invertebrate burrow systems.

    PubMed

    Hale, Rachel; Boardman, Richard; Mavrogordato, Mark N; Sinclair, Ian; Tolhurst, Trevor J; Solan, Martin

    2015-01-01

    The architecture of biogenic structures can be highly influential in determining species contributions to major soil and sediment processes, but detailed 3-D characterisations are rare and descriptors of form and complexity are lacking. Here we provide replicate high-resolution micro-focus computed tomography (μ-CT) data for the complete burrow systems of three co-occurring, but functionally contrasting, sediment-dwelling inter-tidal invertebrates assembled alone, and in combination, in representative model aquaria. These data (≤ 2,000 raw image slices aquarium(-1), isotropic voxel resolution, 81 μm) provide reference models that can be used for the development of novel structural analysis routines that will be of value within the fields of ecology, pedology, geomorphology, palaeobiology, ichnology and mechanical engineering. We also envisage opportunity for those investigating transport networks, vascular systems, plant rooting systems, neuron connectivity patterns, or those developing image analysis or statistics related to pattern or shape recognition. The dataset will allow investigators to develop or test novel methodology and ideas without the need to generate a complete three-dimensional computation of exemplar architecture. PMID:26396743

  15. 3D ultrasound computer tomography: update from a clinical study

    NASA Astrophysics Data System (ADS)

    Hopp, T.; Zapf, M.; Kretzek, E.; Henrich, J.; Tukalo, A.; Gemmeke, H.; Kaiser, C.; Knaudt, J.; Ruiter, N. V.

    2016-04-01

    Ultrasound Computer Tomography (USCT) is a promising new imaging method for breast cancer diagnosis. We developed a 3D USCT system and tested it in a pilot study with encouraging results: 3D USCT was able to depict two carcinomas, which were present in contrast enhanced MRI volumes serving as ground truth. To overcome severe differences in the breast shape, an image registration was applied. We analyzed the correlation between average sound speed in the breast and the breast density estimated from segmented MRIs and found a positive correlation with R=0.70. Based on the results of the pilot study we now carry out a successive clinical study with 200 patients. For this we integrated our reconstruction methods and image post-processing into a comprehensive workflow. It includes a dedicated DICOM viewer for interactive assessment of fused USCT images. A new preview mode now allows intuitive and faster patient positioning. We updated the USCT system to decrease the data acquisition time by approximately factor two and to increase the penetration depth of the breast into the USCT aperture by 1 cm. Furthermore the compute-intensive reflectivity reconstruction was considerably accelerated, now allowing a sub-millimeter volume reconstruction in approximately 16 minutes. The updates made it possible to successfully image first patients in our ongoing clinical study.

  16. High-resolution computed tomography reconstructions of invertebrate burrow systems

    PubMed Central

    Hale, Rachel; Boardman, Richard; Mavrogordato, Mark N.; Sinclair, Ian; Tolhurst, Trevor J.; Solan, Martin

    2015-01-01

    The architecture of biogenic structures can be highly influential in determining species contributions to major soil and sediment processes, but detailed 3-D characterisations are rare and descriptors of form and complexity are lacking. Here we provide replicate high-resolution micro-focus computed tomography (μ-CT) data for the complete burrow systems of three co-occurring, but functionally contrasting, sediment-dwelling inter-tidal invertebrates assembled alone, and in combination, in representative model aquaria. These data (≤2,000 raw image slices aquarium−1, isotropic voxel resolution, 81 μm) provide reference models that can be used for the development of novel structural analysis routines that will be of value within the fields of ecology, pedology, geomorphology, palaeobiology, ichnology and mechanical engineering. We also envisage opportunity for those investigating transport networks, vascular systems, plant rooting systems, neuron connectivity patterns, or those developing image analysis or statistics related to pattern or shape recognition. The dataset will allow investigators to develop or test novel methodology and ideas without the need to generate a complete three-dimensional computation of exemplar architecture. PMID:26396743

  17. Investigating the geometry of pig airways using computed tomography

    NASA Astrophysics Data System (ADS)

    Mansy, Hansen A.; Azad, Md Khurshidul; McMurray, Brandon; Henry, Brian; Royston, Thomas J.; Sandler, Richard H.

    2015-03-01

    Numerical modeling of sound propagation in the airways requires accurate knowledge of the airway geometry. These models are often validated using human and animal experiments. While many studies documented the geometric details of the human airways, information about the geometry of pig airways is scarcer. In addition, the morphology of animal airways can be significantly different from that of humans. The objective of this study is to measure the airway diameter, length and bifurcation angles in domestic pigs using computed tomography. After imaging the lungs of 3 pigs, segmentation software tools were used to extract the geometry of the airway lumen. The airway dimensions were then measured from the resulting 3 D models for the first 10 airway generations. Results showed that the size and morphology of the airways of different animals were similar. The measured airway dimensions were compared with those of the human airways. While the trachea diameter was found to be comparable to the adult human, the diameter, length and branching angles of other airways were noticeably different from that of humans. For example, pigs consistently had an early airway branching from the trachea that feeds the superior (top) right lung lobe proximal to the carina. This branch is absent in the human airways. These results suggested that the human geometry may not be a good approximation of the pig airways and may contribute to increasing the errors when the human airway geometric values are used in computational models of the pig chest.

  18. Image reconstruction in transcranial photoacoustic computed tomography of the brain

    NASA Astrophysics Data System (ADS)

    Mitsuhashi, Kenji; Wang, Lihong V.; Anastasio, Mark A.

    2015-03-01

    Photoacoustic computed tomography (PACT) holds great promise for transcranial brain imaging. However, the strong reflection, scattering, attenuation, and mode-conversion of photoacoustic waves in the skull pose serious challenges to establishing the method. The lack of an appropriate model of solid media in conventional PACT imaging models, which are based on the canonical scalar wave equation, causes a significant model mismatch in the presence of the skull and thus results in deteriorated reconstructed images. The goal of this study was to develop an image reconstruction algorithm that accurately models the skull and thereby ameliorates the quality of reconstructed images. The propagation of photoacoustic waves through the skull was modeled by a viscoelastic stress tensor wave equation, which was subsequently discretized by use of a staggered grid fourth-order finite-difference time-domain (FDTD) method. The matched adjoint of the FDTD-based wave propagation operator was derived for implementing a back-projection operator. Systematic computer simulations were conducted to demonstrate the effectiveness of the back-projection operator for reconstructing images in a realistic three-dimensional PACT brain imaging system. The results suggest that the proposed algorithm can successfully reconstruct images from transcranially-measured pressure data and readily be translated to clinical PACT brain imaging applications.

  19. Computed Tomography (CT) And Picture Archiving And Communication Systems (PACS)

    NASA Astrophysics Data System (ADS)

    Edens, William R.

    1982-01-01

    The Computed Tomography System is aimed at availing the doctor of a non-invasive diagnostic tool to project an image of the patient's anatomy on a interactive display monitor. The total speed of data acquisition to first image is generally the perceived highest system requirement. The System need for archival storage of the images does produce a time limiting restraint on this need. The opportunity for advanced image analysis is at times ignored in deference to film due to the data acquisition impacts on the analysis within a single computer and the clinical needs of the attending physician. The presentation will address the benefits of film, tape and local area networking in the total picture of task distribution, archival storage, and improved analysis availability. It will delve into the dataset sizes and required technology in use within the CT system today. The concepts of multiscanner rooms feeding to a central archival storage facility and/or satellite image analysis stations will be analyzed as to the benefits, costs, and image analysis impacts. Then the projection toward the multi modality analysis system will be visited for benefits and needs. The question of wide area network access needs must ultimately be projected.

  20. A Novel Automated Method for Analyzing Cylindrical Computed Tomography Data

    NASA Technical Reports Server (NTRS)

    Roth, D. J.; Burke, E. R.; Rauser, R. W.; Martin, R. E.

    2011-01-01

    A novel software method is presented that is applicable for analyzing cylindrical and partially cylindrical objects inspected using computed tomography. This method involves unwrapping and re-slicing data so that the CT data from the cylindrical object can be viewed as a series of 2-D sheets in the vertical direction in addition to volume rendering and normal plane views provided by traditional CT software. The method is based on interior and exterior surface edge detection and under proper conditions, is FULLY AUTOMATED and requires no input from the user except the correct voxel dimension from the CT scan. The software is available from NASA in 32- and 64-bit versions that can be applied to gigabyte-sized data sets, processing data either in random access memory or primarily on the computer hard drive. Please inquire with the presenting author if further interested. This software differentiates itself in total from other possible re-slicing software solutions due to complete automation and advanced processing and analysis capabilities.

  1. Physics-based modeling of computed tomography systems

    NASA Astrophysics Data System (ADS)

    Youn, Hanbean; Kim, Ho Kyung; Kam, Soohwa; Kim, Seung Ho; Park, Ji Woong; Jeon, Hosang

    2015-03-01

    We present a theoretical framework describing projections obtained from computed tomography systems considering physics of each component consisting of the systems. The projection model mainly consists of the attenuation of x-ray photons through objects including x-ray scatter and the detection of attenuated/scattered x-ray photons at pixel detector arrays. X-ray photons are attenuated by the Beers-Lambert law and scattered by using the Klein-Nishina formula. The cascaded signal-transfer model for the detector includes x-ray photon detection and light photon conversion/spreading in scintillators, light photon detection in photodiodes, and the addition of electronic noise quanta. On the other hand, image noise is considered by re-distributing the pixel signals in pixel-by-pixel ways at each image formation stage using the proper distribution functions. Instead of iterating the ray tracing over each energy bin in the x-ray spectrum, we first perform the ray tracing for an object only considering the thickness of each component. Then, we assign energy-dependent linear attenuation coefficients to each component in the projected images. This approach reduces the computation time by a factor of the number of energy bins in the x-ray spectrum divided by the number of components in the object compared with the conventional ray-tracing method. All the methods developed in this study are validated in comparisons with the measurements or the Monte Carlo simulations.

  2. Computational Methods for Structural Mechanics and Dynamics

    NASA Technical Reports Server (NTRS)

    Stroud, W. Jefferson (Editor); Housner, Jerrold M. (Editor); Tanner, John A. (Editor); Hayduk, Robert J. (Editor)

    1989-01-01

    Topics addressed include: transient dynamics; transient finite element method; transient analysis in impact and crash dynamic studies; multibody computer codes; dynamic analysis of space structures; multibody mechanics and manipulators; spatial and coplanar linkage systems; flexible body simulation; multibody dynamics; dynamical systems; and nonlinear characteristics of joints.

  3. Proposal of a computed tomography classification for hepatic alveolar echinococcosis

    PubMed Central

    Graeter, Tilmann; Kratzer, Wolfgang; Oeztuerk, Suemeyra; Haenle, Mark Martin; Mason, Richard Andrew; Hillenbrand, Andreas; Kull, Thomas; Barth, Thomas F; Kern, Peter; Gruener, Beate

    2016-01-01

    AIM: To establish a computed tomography (CT)-morphological classification for hepatic alveolar echinococcosis was the aim of the study. METHODS: The CT morphology of hepatic lesions in 228 patients with confirmed alveolar echinococcosis (AE) drawn from the Echinococcus Databank of the University Hospital of Ulm was reviewed retrospectively. For this reason, CT datasets of combined positron emission tomography (PET)-CT examinations were evaluated. The diagnosis of AE was made in patients with unequivocal seropositivity; positive histological findings following diagnostic puncture or partial resection of the liver; and/or findings typical for AE at either ultrasonography, CT, magnetic resonance imaging or PET-CT. The CT-morphological findings were grouped into the new classification scheme. RESULTS: Within the classification a lesion was dedicated to one out of five “primary morphologies” as well as to one out of six “patterns of calcification”. “primary morphology” and “pattern of calcification” are primarily focussed on separately from each other and combined, whereas the “primary morphology” V is not further characterized by a “pattern of calcification”. Based on the five primary morphologies, further descriptive sub-criteria were appended to types I-III. An analysis of the calcification pattern in relation to the primary morphology revealed the exclusive association of the central calcification with type IV primary morphology. Similarly, certain calcification patterns exhibited a clear predominance for other primary morphologies, which underscores the delimitation of the individual primary morphological types from each other. These relationships in terms of calcification patterns extend into the primary morphological sub-criteria, demonstrating the clear subordination of those criteria. CONCLUSION: The proposed CT-morphological classification (EMUC-CT) is intended to facilitate the recognition and interpretation of lesions in hepatic

  4. Development of Proton Computed Tomography for Applications in Proton Therapy

    SciTech Connect

    Bashkirov, Vladimir; Schulte, Reinhard; Coutrakon, George; Erdelyi, Bela; Wong, Kent; Sadrozinski, Hartmut; Penfold, Scott; Rosenfeld, Anatoly; McAllister, Scott; Schubert, Keith

    2009-03-10

    Determination of the Bragg peak position in proton therapy requires accurate knowledge of the electron density and ratio of effective atomic number and mass (Z/A) of the body tissues traversed. While the Z/A ratio is fairly constant for human tissues, the density of tissues varies significantly. One possibility to obtain accurate electron density information of tissues is to use protons of sufficient energy to penetrate the patient and measure their energy loss. From these transmission measurements, it is possible to reconstruct a three-dimensional map of electron densities using algebraic techniques. The interest in proton computed tomography (pCT) has considerably increased in recent years due to the more common use of proton accelerators for cancer treatment world-wide and a modern design concept based on current high-energy physics technology has been suggested. This contribution gives a status update on the pCT project carried out by the pCT Collaboration, a group of institutions sharing interest and expertise in the development of pCT. We will present updated imaging data obtained with a small pCT prototype developed in collaboration with the Santa Cruz Institute of Particle Physics and installed on the proton research beam line at Loma Linda University Medical Center. We will discuss hardware decisions regarding the next-generation pCT scanner, which will permit scanning of head-sized objects. Progress has also been made in the formulation of the most likely path of protons through an object and parallelizable iterative reconstruction algorithms that can be implemented on general-purpose commodity graphics processing units. Finally, we will present simulation studies for utilizing pCT technology for on-line proton dose verification and tumor imaging with positron emission tomography (PET)

  5. Preclinical spectral computed tomography of gold nano-particles

    NASA Astrophysics Data System (ADS)

    Roessl, Ewald; Cormode, David; Brendel, Bernhard; Jürgen Engel, Klaus; Martens, Gerhard; Thran, Axel; Fayad, Zahi; Proksa, Roland

    2011-08-01

    Today's state-of the art clinical computed tomography (CT) scanners exclusively use energy-integrating, scintillation detector technology, despite the fact that a part of the information carried by the transmitted X-ray photons is lost during the detection process. Room-temperature semiconductors, like CdTe or CZT, operated in energy-sensitive photon-counting mode provide information about the energy of every single X-ray detection event. This capability allows novel, promising approaches to selectively image abnormal tissue types like cancerous tissue or atherosclerotic plaque with the CT modality.In this article we report on recent dual K-edge imaging results obtained in the domain of pre-clinical, energy-sensitive photon-counting CT. In this approach, the tuning of threshold levels in the detector electronics to the K-edge energy in the attenuation of contrast agents (CA) offers highly specific, quantitative imaging of the distribution of the CA on top of the conventional, morphological image information. The combination of the high specificity of the K-edge imaging technique together with the powerful tool of targeting specific diseases in the human body by dedicated contrast materials might enrich the CT modality with capabilities of functional imaging known from the nuclear medicine imaging modalities, e.g., positron-emission-tomography but with the additional advantage of high spatial and temporal resolution. We also discuss briefly the technological difficulties to be overcome when translating the technique to human CT imaging and present the results of simulations indicating the feasibility of the K-edge imaging of vulnerable plaque using targeted gold nano-particles as contrast materials. Our experiments in the pre-clinical domain show that dual-K edge imaging of iodine and gold-based CAs is feasible while our simulations for the imaging of gold CAs in the clinical case support the future possibility of translating the technique to human imaging.

  6. Motion management in positron emission tomography/computed tomography for radiation treatment planning.

    PubMed

    Bettinardi, Valentino; Picchio, Maria; Di Muzio, Nadia; Gilardi, Maria Carla

    2012-09-01

    Hybrid positron emission tomography (PET)/computed tomography (CT) scanners combine, in a unique gantry, 2 of the most important diagnostic imaging systems, a CT and a PET tomograph, enabling anatomical (CT) and functional (PET) studies to be performed in a single study session. Furthermore, as the 2 scanners use the same spatial coordinate system, the reconstructed CT and PET images are spatially co-registered, allowing an accurate localization of the functional signal over the corresponding anatomical structure. This peculiarity of the hybrid PET/CT system results in improved tumor characterization for oncological applications, and more recently, it was found to be also useful for target volume definition (TVD) and treatment planning in radiotherapy (RT) applications. In fact, the use of combined PET/CT information has been shown to improve the RT treatment plan when compared with that obtained by a CT alone. A limiting factor to the accuracy of TVD by PET/CT is organ and tumor motion, which is mainly due to patient respiration. In fact, respiratory motion has a degrading effect on PET/CT image quality, and this is also critical for TVD, as it can lead to possible tumor missing or undertreatment. Thus, the management of respiratory motion is becoming an increasingly essential component in RT treatment planning; indeed, it has been recognized that the use of personalized motion information can improve TVD and, consequently, permit increased tumor dosage while sparing surrounding healthy tissues and organs at risk. This review describes the methods used for motion management in PET/CT for radiation treatment planning. The article covers the following: (1) problems caused by organ and lesion motion owing to respiration, and the artifacts generated on CT, PET, and PET/CT images; (2) data acquisition and processing techniques used to manage respiratory motion in PET/CT studies; and (3) the use of personalized motion information for TVD and radiation treatment planning.

  7. Quantitative Assessment of Radionuclide Uptake and Positron Emission Tomography-computed Tomography Image Contrast

    PubMed Central

    Francis, Hasford; Amuasi, John Humphrey; Kwame, Kyere Augustine; Vangu, Mboyo Di Tamba

    2016-01-01

    Radionuclide uptake and contrast for positron emission tomography-computed tomography (PET-CT) images have been assessed in this study using NEMA image quality phantom filled with background activity concentration of 5.3 kBq/mL fluorodeoxyglucose (F-18 FDG). Spheres in the phantom were filled in turns with water to mimic cold lesions and FDG of higher activity concentrations to mimic tumor sites. Transaxial image slices were acquired on the PET-CT system and used for the evaluation of mean standard uptake value (SUVmean) and contrasts for varying sphere sizes at different activity concentrations of 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL. For spheres of same sizes, SUVmean increased with increase in activity concentration. SUVmean was increased by 80.6%, 83.5%, 63.2%, 87.4%, and 63.2% when activity concentrations of spheres with a diameter of 1.3 cm, 1.7 cm, 2.2 cm, 2.8 cm, and 3.7 cm, respectively, were increased from 10.6 kBq/mL to 42.4 kBq/mL. Average percentage contrast between cold spheres (cold lesions) and background activity concentration was estimated to be 89.96% for the spheres. Average contrast for the spheres containing 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL were found to be 110.92%, 134.48%, and 150.52%, respectively. The average background contrast variability was estimated to be 2.97% at 95% confidence interval (P < 0.05). PMID:27650938

  8. Quantitative Assessment of Radionuclide Uptake and Positron Emission Tomography-computed Tomography Image Contrast

    PubMed Central

    Francis, Hasford; Amuasi, John Humphrey; Kwame, Kyere Augustine; Vangu, Mboyo Di Tamba

    2016-01-01

    Radionuclide uptake and contrast for positron emission tomography-computed tomography (PET-CT) images have been assessed in this study using NEMA image quality phantom filled with background activity concentration of 5.3 kBq/mL fluorodeoxyglucose (F-18 FDG). Spheres in the phantom were filled in turns with water to mimic cold lesions and FDG of higher activity concentrations to mimic tumor sites. Transaxial image slices were acquired on the PET-CT system and used for the evaluation of mean standard uptake value (SUVmean) and contrasts for varying sphere sizes at different activity concentrations of 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL. For spheres of same sizes, SUVmean increased with increase in activity concentration. SUVmean was increased by 80.6%, 83.5%, 63.2%, 87.4%, and 63.2% when activity concentrations of spheres with a diameter of 1.3 cm, 1.7 cm, 2.2 cm, 2.8 cm, and 3.7 cm, respectively, were increased from 10.6 kBq/mL to 42.4 kBq/mL. Average percentage contrast between cold spheres (cold lesions) and background activity concentration was estimated to be 89.96% for the spheres. Average contrast for the spheres containing 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL were found to be 110.92%, 134.48%, and 150.52%, respectively. The average background contrast variability was estimated to be 2.97% at 95% confidence interval (P < 0.05).

  9. Relationship of computed tomography perfusion and positron emission tomography to tumour progression in malignant glioma

    SciTech Connect

    Yeung, Timothy P C; Yartsev, Slav; Lee, Ting-Yim; Wong, Eugene; He, Wenqing; Fisher, Barbara; VanderSpek, Lauren L; Macdonald, David; Bauman, Glenn

    2014-02-15

    Introduction: This study aimed to explore the potential for computed tomography (CT) perfusion and 18-Fluorodeoxyglucose positron emission tomography (FDG-PET) in predicting sites of future progressive tumour on a voxel-by-voxel basis after radiotherapy and chemotherapy. Methods: Ten patients underwent pre-radiotherapy magnetic resonance (MR), FDG-PET and CT perfusion near the end of radiotherapy and repeated post-radiotherapy follow-up MR scans. The relationships between these images and tumour progression were assessed using logistic regression. Cross-validation with receiver operating characteristic (ROC) analysis was used to assess the value of these images in predicting sites of tumour progression. Results: Pre-radiotherapy MR-defined gross tumour; near-end-of-radiotherapy CT-defined enhancing lesion; CT perfusion blood flow (BF), blood volume (BV) and permeability-surface area (PS) product; FDG-PET standard uptake value (SUV); and SUV:BF showed significant associations with tumour progression on follow-up MR imaging (P < 0.0001). The mean sensitivity (±standard deviation), specificity and area under the ROC curve (AUC) of PS were 0.64 ± 0.15, 0.74 ± 0.07 and 0.72 ± 0.12 respectively. This mean AUC was higher than that of the pre-radiotherapy MR-defined gross tumour and near-end-of-radiotherapy CT-defined enhancing lesion (both AUCs = 0.6 ± 0.1, P ≤ 0.03). The multivariate model using BF, BV, PS and SUV had a mean AUC of 0.8 ± 0.1, but this was not significantly higher than the PS only model. Conclusion: PS is the single best predictor of tumour progression when compared to other parameters, but voxel-based prediction based on logistic regression had modest sensitivity and specificity.

  10. Quantitative Assessment of Radionuclide Uptake and Positron Emission Tomography-computed Tomography Image Contrast.

    PubMed

    Francis, Hasford; Amuasi, John Humphrey; Kwame, Kyere Augustine; Vangu, Mboyo Di Tamba

    2016-09-01

    Radionuclide uptake and contrast for positron emission tomography-computed tomography (PET-CT) images have been assessed in this study using NEMA image quality phantom filled with background activity concentration of 5.3 kBq/mL fluorodeoxyglucose (F-18 FDG). Spheres in the phantom were filled in turns with water to mimic cold lesions and FDG of higher activity concentrations to mimic tumor sites. Transaxial image slices were acquired on the PET-CT system and used for the evaluation of mean standard uptake value (SUVmean) and contrasts for varying sphere sizes at different activity concentrations of 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL. For spheres of same sizes, SUVmean increased with increase in activity concentration. SUVmean was increased by 80.6%, 83.5%, 63.2%, 87.4%, and 63.2% when activity concentrations of spheres with a diameter of 1.3 cm, 1.7 cm, 2.2 cm, 2.8 cm, and 3.7 cm, respectively, were increased from 10.6 kBq/mL to 42.4 kBq/mL. Average percentage contrast between cold spheres (cold lesions) and background activity concentration was estimated to be 89.96% for the spheres. Average contrast for the spheres containing 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL were found to be 110.92%, 134.48%, and 150.52%, respectively. The average background contrast variability was estimated to be 2.97% at 95% confidence interval (P < 0.05). PMID:27650938

  11. Single-photon emission computed tomography and positron-emission tomography assays for tissue oxygenation.

    PubMed

    Chapman, J D; Schneider, R F; Urbain, J L; Hanks, G E

    2001-01-01

    Radiotherapy prescription can now be customized to target the major mechanism(s) of resistance of individual tumors. In that regard, functional imaging techniques should be exploited to identify the dominant mechanism(s). Tumor biology research has identified several mechanisms of tumor resistance that may be unique to radiation treatments. These fall into 3 broad areas associated with (1) tumor hypoxic fraction, (2) tumor growth rate, (3) and the intrinsic radiosensitivity of tumor clonogens. Imaging research has markers in various stages of development for quantifying relevant information about each of these mechanisms, and those that measure tumor oxygenation and predict for radioresistance are the most advanced. Positron-emission tomography (PET) measurement of oxygen 15 has yielded important information, particularly about brain tissue perfusion, metabolism, and function. Indirect markers of tumor hypoxia have exploited the covalent binding of bioreductive intermediates of azomycin-containing compounds whose uptakes are inversely proportional to intracellular oxygen concentrations. Pilot clinical studies with single-photon emission computed tomography (SPECT) and PET detection of radiolabeled markers to tumor hypoxia have been reported. Recently, other studies have attempted to exploit the reduction properties of both technetium and copper chelates for the selective deposition of radioactive metals in hypoxic tissues. A growing number of potentially useful isotopes are now available for labeling several novel chemicals that could have the appropriate specificity and sensitivity. Preclinical studies with "microSPECT" and "microPET" will be important to define the optimal radiodiagnostic(s) for measuring tissue oxygenation and for determining the time after their administration for optimal hypoxic signal acquisition. Radiolabeled markers of growth kinetics and intrinsic radiosensitivity of cells in solid tumors are also being developed. We conclude that

  12. Enhancement of positron emission tomography-computed tomography image quality using the principle of stochastic resonance

    PubMed Central

    Pandey, Anil Kumar; Sharma, Sanjay Kumar; Sharma, Punit; Singh, Harmandeep; Patel, Chetan; Sarkar, Kaushik; Kumar, Rakesh; Bal, Chandra Sekhar

    2014-01-01

    Purpose: Acquisition of higher counts improves visual perception of positron emission tomography-computed tomography (PET-CT) image. Larger radiopharmaceutical doses (implies more radiation dose) are administered to acquire this count in a short time period. However, diagnostic information does not increase after a certain threshold of counts. This study was conducted to develop a post processing method based on principle of “stochastic resonance” to improve visual perception of the PET-CT image having a required threshold counts. Materials and Methods: PET-CT images (JPEG file format) with low, medium, and high counts in the image were included in this study. The image was corrupted with the addition of Poisson noise. The amplitude of the Poisson noise was adjusted by dividing each pixel by a constant 1, 2, 4, 8, 16, and 32. The best amplitude of the noise that gave best images quality was selected based on high value of entropy of the output image, high value of structural similarity index and feature similarity index. Visual perception of the image was evaluated by two nuclear medicine physicians. Results: The variation in structural and feature similarity of the image was not appreciable visually, but statistically images deteriorated as the noise amplitude increases although maintaining structural (above 70%) and feature (above 80%) similarity of input images in all cases. We obtained the best image quality at noise amplitude “4” in which 88% structural and 95% feature similarity of the input images was retained. Conclusion: This method of stochastic resonance can be used to improve the visual perception of the PET-CT image. This can indirectly lead to reduction of radiation dose. PMID:25400362

  13. Anomalous Morphology of an Ectopic Tooth in the Maxillary Sinus on Three-Dimensional Computed Tomography Images

    PubMed Central

    Lai, Yee-Tak Alta; Luk, Yiu Shiobhon; Fung, Kai-Hung

    2013-01-01

    We describe a case of an incidentally-diagnosed ectopic tooth showing anomalous morphology in the maxillary antrum, using three-dimensional reconstruction of computed tomography images of the tooth obtained by multi-detector computed tomography. PMID:23705035

  14. Using the technique of computed tomography for nondestructive analysis of pharmaceutical dosage forms

    NASA Astrophysics Data System (ADS)

    de Oliveira, José Martins, Jr.; Mangini, F. Salvador; Carvalho Vila, Marta Maria Duarte; ViníciusChaud, Marco

    2013-05-01

    This work presents an alternative and non-conventional technique for evaluatingof physic-chemical properties of pharmaceutical dosage forms, i.e. we used computed tomography (CT) technique as a nondestructive technique to visualize internal structures of pharmaceuticals dosage forms and to conduct static and dynamical studies. The studies were conducted involving static and dynamic situations through the use of tomographic images, generated by the scanner at University of Sorocaba - Uniso. We have shown that through the use of tomographic images it is possible to conduct studies of porosity, densities, analysis of morphological parameters and performing studies of dissolution. Our results are in agreement with the literature, showing that CT is a powerful tool for use in the pharmaceutical sciences.

  15. Employing temporal self-similarity across the entire time domain in computed tomography reconstruction.

    PubMed

    Kazantsev, D; Van Eyndhoven, G; Lionheart, W R B; Withers, P J; Dobson, K J; McDonald, S A; Atwood, R; Lee, P D

    2015-06-13

    There are many cases where one needs to limit the X-ray dose, or the number of projections, or both, for high frame rate (fast) imaging. Normally, it improves temporal resolution but reduces the spatial resolution of the reconstructed data. Fortunately, the redundancy of information in the temporal domain can be employed to improve spatial resolution. In this paper, we propose a novel regularizer for iterative reconstruction of time-lapse computed tomography. The non-local penalty term is driven by the available prior information and employs all available temporal data to improve the spatial resolution of each individual time frame. A high-resolution prior image from the same or a different imaging modality is used to enhance edges which remain stationary throughout the acquisition time while dynamic features tend to be regularized spatially. Effective computational performance together with robust improvement in spatial and temporal resolution makes the proposed method a competitive tool to state-of-the-art techniques.

  16. Visualization of Computational Fluid Dynamics

    NASA Technical Reports Server (NTRS)

    Gerald-Yamasaki, Michael; Hultquist, Jeff; Bryson, Steve; Kenwright, David; Lane, David; Walatka, Pamela; Clucas, Jean; Watson, Velvin; Lasinski, T. A. (Technical Monitor)

    1995-01-01

    Scientific visualization serves the dual purpose of exploration and exposition of the results of numerical simulations of fluid flow. Along with the basic visualization process which transforms source data into images, there are four additional components to a complete visualization system: Source Data Processing, User Interface and Control, Presentation, and Information Management. The requirements imposed by the desired mode of operation (i.e. real-time, interactive, or batch) and the source data have their effect on each of these visualization system components. The special requirements imposed by the wide variety and size of the source data provided by the numerical simulation of fluid flow presents an enormous challenge to the visualization system designer. We describe the visualization system components including specific visualization techniques and how the mode of operation and source data requirements effect the construction of computational fluid dynamics visualization systems.

  17. Sinonasal Neoplasia – Clinicopathological Profile And Importance of Computed Tomography

    PubMed Central

    Sarawagi, Radha; Raghuwanshi, Sameer; Yadav, Pankaj Kumar

    2015-01-01

    Background Nasal cavity and Paranasal sinus malignancies are very rare, in which maxillary sinus is the commonest, followed by ethmoid, frontal and sphenoid sinus. Computed Tomography (CT) & Magnetic Resonance Imaging (MRI) play a key role in diagnosis, staging and management of paranasal sinuses and nasal pathologies. Multiplanar imaging in CT helps better imaging of critical anatomical areas. Aim of our study was to study the incidence, clinical features, CT features and its importance in the management of sinonasal neoplasms. Materials and Methods This prospective study was carried out in a tertiary care hospital of MP, India. Consecutive 40 histologically proven cases of sinonasal neoplasia who visited the Department of Otorhinolaryngology and Radiotherapy are included in our study. Demography and clinical features were recorded. Cases of nasal and paranasal sinus masses diagnosed on CT attending ENT and Radiotherapy OPD or admitted in the Radiotherapy ward forms the material of this study. This included patients of both sexes and all ages. Histopathological examination was asked to confirm the diagnosis made on CT. Results There were total 40 cases of sinonasal neoplasia among which 24 were benign. Almost all the benign cases were seen in the age group <40 y with mean age of 20 y and most of the malignant cases were seen in the age group above 40 y with mean age of 55 y. In our study we found male preponderance with male female ratio of 4:1 in both benign and malignant conditions. The commonest presenting symptoms of the patients with sinonasal masses in our study was nasal obstruction (75%) and nasal discharge (67.5%) followed by nasal mass (65%), epistaxis (62.5%) and headache (60%). Angiofibroma and papilloma were the commonest benign lesions. Commonest malignant lesion was squamous cell carcinoma. Of the malignant Sinonasal tumours studied in our series, maxillary sinus was involved in 13, ethmoid sinuses and nasal cavity in 10 cases each, and frontal

  18. Role of Positron Emission Tomography-Computed Tomography in the Management of Anal Cancer

    SciTech Connect

    Mistrangelo, Massimiliano; Pelosi, Ettore; Bello, Marilena; Ricardi, Umberto; Milanesi, Enrica; Cassoni, Paola; Baccega, Massimo; Filippini, Claudia; Racca, Patrizia; Lesca, Adriana; Munoz, Fernando H.; Fora, Gianluca; Skanjeti, Andrea; Cravero, Francesca; Morino, Mario

    2012-09-01

    Purpose: Pre- and post-treatment staging of anal cancer are often inaccurate. The role of positron emission tomograpy-computed tomography (PET-CT) in anal cancer is yet to be defined. The aim of the study was to compare PET-CT with CT scan, sentinel node biopsy results of inguinal lymph nodes, and anal biopsy results in staging and in follow-up of anal cancer. Methods and Materials: Fifty-three consecutive patients diagnosed with anal cancer underwent PET-CT. Results were compared with computed tomography (CT), performed in 40 patients, and with sentinel node biopsy (SNB) (41 patients) at pretreatment workup. Early follow-up consisted of a digital rectal examination, an anoscopy, a PET-CT scan, and anal biopsies performed at 1 and 3 months after the end of treatment. Data sets were then compared. Results: At pretreatment assessment, anal cancer was identified by PET-CT in 47 patients (88.7%) and by CT in 30 patients (75%). The detection rates rose to 97.9% with PET-CT and to 82.9% with CT (P=.042) when the 5 patients who had undergone surgery prior to this assessment and whose margins were positive at histological examination were censored. Perirectal and/or pelvic nodes were considered metastatic by PET-CT in 14 of 53 patients (26.4%) and by CT in 7 of 40 patients (17.5%). SNB was superior to both PET-CT and CT in detecting inguinal lymph nodes. PET-CT upstaged 37.5% of patients and downstaged 25% of patients. Radiation fields were changed in 12.6% of patients. PET-CT at 3 months was more accurate than PET-CT at 1 month in evaluating outcomes after chemoradiation therapy treatment: sensitivity was 100% vs 66.6%, and specificity was 97.4% vs 92.5%, respectively. Median follow-up was 20.3 months. Conclusions: In this series, PET-CT detected the primary tumor more often than CT. Staging of perirectal/pelvic or inguinal lymph nodes was better with PET-CT. SNB was more accurate in staging inguinal lymph nodes.

  19. Computer-aided classification of lung nodules on computed tomography images via deep learning technique.

    PubMed

    Hua, Kai-Lung; Hsu, Che-Hao; Hidayati, Shintami Chusnul; Cheng, Wen-Huang; Chen, Yu-Jen

    2015-01-01

    Lung cancer has a poor prognosis when not diagnosed early and unresectable lesions are present. The management of small lung nodules noted on computed tomography scan is controversial due to uncertain tumor characteristics. A conventional computer-aided diagnosis (CAD) scheme requires several image processing and pattern recognition steps to accomplish a quantitative tumor differentiation result. In such an ad hoc image analysis pipeline, every step depends heavily on the performance of the previous step. Accordingly, tuning of classification performance in a conventional CAD scheme is very complicated and arduous. Deep learning techniques, on the other hand, have the intrinsic advantage of an automatic exploitation feature and tuning of performance in a seamless fashion. In this study, we attempted to simplify the image analysis pipeline of conventional CAD with deep learning techniques. Specifically, we introduced models of a deep belief network and a convolutional neural network in the context of nodule classification in computed tomography images. Two baseline methods with feature computing steps were implemented for comparison. The experimental results suggest that deep learning methods could achieve better discriminative results and hold promise in the CAD application domain.

  20. Computer-aided classification of lung nodules on computed tomography images via deep learning technique

    PubMed Central

    Hua, Kai-Lung; Hsu, Che-Hao; Hidayati, Shintami Chusnul; Cheng, Wen-Huang; Chen, Yu-Jen

    2015-01-01

    Lung cancer has a poor prognosis when not diagnosed early and unresectable lesions are present. The management of small lung nodules noted on computed tomography scan is controversial due to uncertain tumor characteristics. A conventional computer-aided diagnosis (CAD) scheme requires several image processing and pattern recognition steps to accomplish a quantitative tumor differentiation result. In such an ad hoc image analysis pipeline, every step depends heavily on the performance of the previous step. Accordingly, tuning of classification performance in a conventional CAD scheme is very complicated and arduous. Deep learning techniques, on the other hand, have the intrinsic advantage of an automatic exploitation feature and tuning of performance in a seamless fashion. In this study, we attempted to simplify the image analysis pipeline of conventional CAD with deep learning techniques. Specifically, we introduced models of a deep belief network and a convolutional neural network in the context of nodule classification in computed tomography images. Two baseline methods with feature computing steps were implemented for comparison. The experimental results suggest that deep learning methods could achieve better discriminative results and hold promise in the CAD application domain. PMID:26346558

  1. Detecting apoptosis using dynamic light scattering with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Farhat, Golnaz; Mariampillai, Adrian; Yang, Victor X. D.; Czarnota, Gregory J.; Kolios, Michael C.

    2011-07-01

    A dynamic light scattering technique is implemented using optical coherence tomography (OCT) to measure the change in intracellular motion as cells undergo apoptosis. Acute myeloid leukemia cells were treated with cisplatin and imaged at a frame rate of 166 Hz using a 1300 nm swept-source OCT system at various times over a period of 48 h. Time correlation analysis of the speckle intensities indicated a significant increase in intracellular motion 24 h after treatment. This rise in intracellular motion correlated with histological findings of irregularly shaped and fragmented cells indicative of cell membrane blebbing and fragmentation.

  2. High Speed Optical Tomography System for Imaging Dynamic Transparent Media

    NASA Astrophysics Data System (ADS)

    McMackin, Lenore; Hugo, Ronald J.; Pierson, R. E.; Truman, C. R.

    1997-11-01

    We describe the design and operation of a high speed optical tomography system for measuring two-dimensional images of a dynamic phase object at a rate of 5 kHz. Data from a set of eight Hartmann wavefront sensors is back-projected to produce phase images showing the details of the inner structure of a heated air flow. The tomographic reconstructions have a spatial resolution of approximately 2.0 mm and can measure temperature variations across the flow with an accuracy of about 0.7 C. Series of animated reconstructions at different downstream locations illustrate the development of flow structure and the effect of acoustic flow forcing.

  3. Mediastinal lymph node staging of non-small-cell lung cancer: a prospective comparison of computed tomography and positron emission tomography.

    PubMed

    Scott, W J; Gobar, L S; Terry, J D; Dewan, N A; Sunderland, J J

    1996-03-01

    We compared the abilities of positron emission tomography and computed tomography to detect N2 or N3 lymph node metastases (N2 or N3) in patients with lung cancer. Positron emission tomography detects increased rates of glucose uptake, characteristic of malignant cells. Patients with peripheral tumors smaller than 2 cm and a normal mediastinum were ineligible. All patients underwent computed tomography, positron emission tomography, and surgical staging. The American Thoracic Society lymph node map was used. Computed and positron emission tomographic scans were read by separate radiologists blinded to surgical staging results. Lymph nodes were "positive" by computed tomography if larger than 1.0 cm in short-axis diameter. Standardized uptake values were recorded from areas on positron emission tomography corresponding to those from which biopsy specimens were taken; if greater than 4.2, they were called "positive." Seventy-five lymph node stations (2.8 per patient) were analyzed in 27 patients. Computed tomography incorrectly staged the mediastinum as positive for metastases in three patients and as negative for metastases in three patients. Sensitivity and specificity of computed tomographic scans were 67% and 83%, respectively. Positron emission tomography correctly staged the mediastinum in all 27 patients. When analyzed by individual node station, there were four false positive and four false negative results by computed tomography (sensitivity = 60%, specificity = 93%, positive predictive value = 60%). Positron emission tomography mislabeled one node station as positive (100% sensitive, 98% specific, positive predictive value 91%). The differences were significant when the data were analyzed both for individual lymph node stations (p = 0.039) and for patients (p = 0.031) (McNemar test). Positron emission tomography and computed tomography are more accurate than computed tomography alone in detecting mediastinal lymph node metastases from non-small-cell lung

  4. Full-direct method for imaging pharmacokinetic parameters in dynamic fluorescence molecular tomography

    NASA Astrophysics Data System (ADS)

    Zhang, Guanglei; Pu, Huangsheng; He, Wei; Liu, Fei; Luo, Jianwen; Bai, Jing

    2015-02-01

    Images of pharmacokinetic parameters (also known as parametric images) in dynamic fluorescence molecular tomography (FMT) can provide three-dimensional metabolic information for biological studies and drug development. However, the ill-posed nature of FMT and the high temporal variation of fluorophore concentration together make it difficult to obtain accurate parametric images in small animals in vivo. In this letter, we present a method to directly reconstruct the parametric images from the boundary measurements based on hybrid FMT/X-ray computed tomography (XCT) system. This method can not only utilize structural priors obtained from the XCT system to mitigate the ill-posedness of FMT but also make full use of the temporal correlations of boundary measurements to model the high temporal variation of fluorophore concentration. The results of numerical simulation and mouse experiment demonstrate that the proposed method leads to significant improvements in the reconstruction quality of parametric images.

  5. Full-direct method for imaging pharmacokinetic parameters in dynamic fluorescence molecular tomography

    SciTech Connect

    Zhang, Guanglei; Pu, Huangsheng; Liu, Fei; Bai, Jing; He, Wei; Luo, Jianwen

    2015-02-23

    Images of pharmacokinetic parameters (also known as parametric images) in dynamic fluorescence molecular tomography (FMT) can provide three-dimensional metabolic information for biological studies and drug development. However, the ill-posed nature of FMT and the high temporal variation of fluorophore concentration together make it difficult to obtain accurate parametric images in small animals in vivo. In this letter, we present a method to directly reconstruct the parametric images from the boundary measurements based on hybrid FMT/X-ray computed tomography (XCT) system. This method can not only utilize structural priors obtained from the XCT system to mitigate the ill-posedness of FMT but also make full use of the temporal correlations of boundary measurements to model the high temporal variation of fluorophore concentration. The results of numerical simulation and mouse experiment demonstrate that the proposed method leads to significant improvements in the reconstruction quality of parametric images.

  6. [Diagnosis. Radiological study. Ultrasound, computed tomography and magnetic resonance imaging].

    PubMed

    Gallo Vallejo, Francisco Javier; Giner Ruiz, Vicente

    2014-01-01

    Because of its low cost, availability in primary care and ease of interpretation, simple X-ray should be the first-line imaging technique used by family physicians for the diagnosis and/or follow-up of patients with osteoarthritis. Nevertheless, this technique should only be used if there are sound indications and if the results will influence decision-making. Despite the increase of indications in patients with rheumatological disease, the role of ultrasound in patients with osteoarthritis continues to be limited. Computed tomography (CT) is of some -although limited- use in osteoarthritis, especially in the study of complex joints (such as the sacroiliac joint and facet joints). Magnetic resonance imaging (MRI) has represented a major advance in the evaluation of joint cartilage and subchondral bone in patients with osteoarthritis but, because of its high cost and diagnostic-prognostic yield, this technique should only be used in highly selected patients. The indications for ultrasound, CT and MRI in patients with osteoarthritis continue to be limited in primary care and often coincide with situations in which the patient may require hospital referral. Patient safety should be bourne in mind. Patients should be protected from excessive ionizing radiation due to unnecessary repeat X-rays or inadequate views or to requests for tests such as CT, when not indicated.

  7. The application of computed tomography in wound ballistics research

    NASA Astrophysics Data System (ADS)

    Tsiatis, Nick; Moraitis, Konstantinos; Papadodima, Stavroula; Spiliopoulou, Chara; Kelekis, Alexis; Kelesis, Christos; Efstathopoulos, Efstathios; Kordolaimi, Sofia; Ploussi, Agapi

    2015-09-01

    In wound ballistics research there is a relationship between the data that characterize a bullet and the injury resulted after shooting when it perforates the human body. The bullet path in the human body following skin perforation as well as the damaging effect cannot always be predictable as they depend on various factors such as the bullet's characteristics (velocity, distance, type of firearm and so on) and the tissue types that the bullet passes through. The purpose of this presentation is to highlight the contribution of Computed Tomography (CT) in wound ballistics research. Using CT technology and studying virtual “slices” of specific areas on scanned human bodies, allows the evaluation of density and thickness of the skin, the subcutaneous tissue, the muscles, the vital organs and the bones. Density data taken from Hounsfield units can be converted in g/ml by using the appropriate software. By evaluating the results of this study, the anatomy of the human body utilizing ballistic gel will be reproduced in order to simulate the path that a bullet follows. The biophysical analysis in wound ballistics provides another application of CT technology, which is commonly used for diagnostic and therapeutic purposes in various medical disciplines.

  8. Computed tomography for staging esophageal and gastroesophageal cancer: reevaluation

    SciTech Connect

    Thompson, W.M.; Halvorsen, R.A.; Foster, W.L. Jr.; Williford, M.E.; Postlethwait, R.W.; Korobkin, M.

    1983-11-01

    A reevaluation of computed tomography (CT) for staging carcinoma of the esophagus and gastroesophageal junction was performed in 76 patients. For comparison 26 patients without carcinoma of the esophagus with a normal mediastinum at surgery were included in the evaluation. Four radiologists evaluated the CT scans without knowledge of the diagnosis. After determining if there was an adequate amount of fat, they were asked to evaluate each case for the presence or absence of local invasion and distant metastases. The radiologists correctly identified all 26 normal patients. Eighteen of the 76 carcinoma had a paucity of fat, but only six were thought to have truly indeterminate scans. CT correctly identified 40 of the 44 esophageal carcinoma patients with mediastinal invasion and 11 of the 15 patients without invasion (accuracy 88%). CT correctly identified 15 of 19 patients with distant abdominal metastases and 28 of 30 patients without metastases (accuracy 88%). CT was only 50% accurate in predicting the presence or absence of invasion in the 12 patients with gastroesophageal junction tumors and only 58% accurate in predicting distant metastases. CT correctly staged 46(94%) of 49 patients with esophageal carcinoma but only five (42%) of 12 patients with gastroesophageal junction tumors. These results confirm that CT should be used as a major staging method in all patients with esophageal carcinoma.

  9. X-ray computed tomography for additive manufacturing: a review

    NASA Astrophysics Data System (ADS)

    Thompson, A.; Maskery, I.; Leach, R. K.

    2016-07-01

    In this review, the use of x-ray computed tomography (XCT) is examined, identifying the requirement for volumetric dimensional measurements in industrial verification of additively manufactured (AM) parts. The XCT technology and AM processes are summarised, and their historical use is documented. The use of XCT and AM as tools for medical reverse engineering is discussed, and the transition of XCT from a tool used solely for imaging to a vital metrological instrument is documented. The current states of the combined technologies are then examined in detail, separated into porosity measurements and general dimensional measurements. In the conclusions of this review, the limitation of resolution on improvement of porosity measurements and the lack of research regarding the measurement of surface texture are identified as the primary barriers to ongoing adoption of XCT in AM. The limitations of both AM and XCT regarding slow speeds and high costs, when compared to other manufacturing and measurement techniques, are also noted as general barriers to continued adoption of XCT and AM.

  10. Validation of a Prototype Optical Computed Tomography System

    PubMed Central

    Zakariaee, Seyed Salman; Molazadeh, Mikaeil; Takavar, Abbas; Shirazi, Alireza; Mesbahi, Asghar; Zeinali, Ahad

    2015-01-01

    In radiation cancer treatments, the most of the side effects could be minimized using a proper dosimeter. Gel dosimeter is the only three-dimensional dosimeter and magnetic resonance imaging (MRI) is the gold standard method for gel dosimeter readout. Because of hard accessibility and high cost of sample reading by MRI systems, some other alternative methods were developed. The optical computed tomography (OCT) method could be considered as the most promising alternative method that has been studied widely. In the current study, gel dosimeter scanning using a prototype optical scanner and validation of this optical scanner was performed. Optical absorbance of the irradiated gel samples was determined by both of conventional spectrophotometer and the fabricated OCT system at 632 nm. Furthermore, these irradiated vials were scanned by a 1.5 T MRI. The slope of the curves was extracted as the dose-response sensitivity. The R2-dose sensitivity measured by MRI method was 0.1904 and 0.113 for NIPAM and PAGAT gels, respectively. The optical dose sensitivity obtained by conventional spectrophotometer and the fabricated optical scanner was 0.0453 and 0.0442 for NIPAM gels and 0.0244 and 0.0242 for PAGAT gels, respectively. The scanning results of the absorbed dose values showed that the new OCT and conventional spectrophotometer were in fair agreement. From the results, it could be concluded that the fabricated system is able to quantize the absorbed dose values in polymer gel samples with acceptable accuracy. PMID:26120572

  11. Validation of a Prototype Optical Computed Tomography System.

    PubMed

    Zakariaee, Seyed Salman; Molazadeh, Mikaeil; Takavar, Abbas; Shirazi, Alireza; Mesbahi, Asghar; Zeinali, Ahad

    2015-01-01

    In radiation cancer treatments, the most of the side effects could be minimized using a proper dosimeter. Gel dosimeter is the only three-dimensional dosimeter and magnetic resonance imaging (MRI) is the gold standard method for gel dosimeter readout. Because of hard accessibility and high cost of sample reading by MRI systems, some other alternative methods were developed. The optical computed tomography (OCT) method could be considered as the most promising alternative method that has been studied widely. In the current study, gel dosimeter scanning using a prototype optical scanner and validation of this optical scanner was performed. Optical absorbance of the irradiated gel samples was determined by both of conventional spectrophotometer and the fabricated OCT system at 632 nm. Furthermore, these irradiated vials were scanned by a 1.5 T MRI. The slope of the curves was extracted as the dose-response sensitivity. The R2-dose sensitivity measured by MRI method was 0.1904 and 0.113 for NIPAM and PAGAT gels, respectively. The optical dose sensitivity obtained by conventional spectrophotometer and the fabricated optical scanner was 0.0453 and 0.0442 for NIPAM gels and 0.0244 and 0.0242 for PAGAT gels, respectively. The scanning results of the absorbed dose values showed that the new OCT and conventional spectrophotometer were in fair agreement. From the results, it could be concluded that the fabricated system is able to quantize the absorbed dose values in polymer gel samples with acceptable accuracy. PMID:26120572

  12. Additive Manufacturing of Anatomical Models from Computed Tomography Scan Data.

    PubMed

    Gür, Y

    2014-12-01

    The purpose of the study presented here was to investigate the manufacturability of human anatomical models from Computed Tomography (CT) scan data via a 3D desktop printer which uses fused deposition modelling (FDM) technology. First, Digital Imaging and Communications in Medicine (DICOM) CT scan data were converted to 3D Standard Triangle Language (STL) format by using In Vaselius digital imaging program. Once this STL file is obtained, a 3D physical version of the anatomical model can be fabricated by a desktop 3D FDM printer. As a case study, a patient's skull CT scan data was considered, and a tangible version of the skull was manufactured by a 3D FDM desktop printer. During the 3D printing process, the skull was built using acrylonitrile-butadiene-styrene (ABS) co-polymer plastic. The printed model showed that the 3D FDM printing technology is able to fabricate anatomical models with high accuracy. As a result, the skull model can be used for preoperative surgical planning, medical training activities, implant design and simulation to show the potential of the FDM technology in medical field. It will also improve communication between medical stuff and patients. Current result indicates that a 3D desktop printer which uses FDM technology can be used to obtain accurate anatomical models.

  13. Digital Radiography and Computed Tomography (DRCT) Product Improvement Plan (PIP)

    SciTech Connect

    Tim Roney; Bob Pink; Karen Wendt; Robert Seifert; Mike Smith

    2010-12-01

    The Idaho National Laboratory (INL) has been developing and deploying x-ray inspection systems for chemical weapons containers for the past 12 years under the direction of the Project Manager for Non-Stockpile Chemical Materiel (PMNSCM). In FY-10 funding was provided to advance the capabilities of these systems through the DRCT (Digital Radiography and Computed Tomography) Product Improvement Plan (PIP), funded by the PMNSCM. The DRCT PIP identified three research tasks; end user study, detector evaluation and DRCT/PINS integration. Work commenced in February, 2010. Due to the late start and the schedule for field inspection of munitions at various sites, it was not possible to spend sufficient field time with operators to develop a complete end user study. We were able to interact with several operators, principally Mr. Mike Rowan who provided substantial useful input through several discussions and development of a set of field notes from the Pueblo, CO field mission. We will be pursuing ongoing interactions with field personnel as opportunities arise in FY-11.

  14. Evaluation of variations in sinonasal region with computed tomography

    PubMed Central

    Dasar, Ufuk; Gokce, Erkan

    2016-01-01

    AIM: To investigate the frequency of anatomical variations in sinonasal region and association of these variations with mucosal diseases. METHODS: The study included 400 cases (191 female and 209 male) who were considered to have preliminary diagnoses of sinonasal pathology and who had paranasal sinus computed tomography (CT) examination in axial plane. Reformatted CT images were studied in all planes. RESULTS: Age range of the patients was 20-83 (mean 40.26 ± 14.85). Most commonly detected anatomical variation was Agger nasi cell (74.8%). There was a significant association between clinoid process pneumatization and protrusion of internal carotid arteries and optic nerves into sphenoid sinus (P < 0.001). Besides, the relationships between pterygoid process pneumatization and protrusion of vidian nerve into sphenoid sinus, and between pneumatization of large sphenoid wing and protrusion of maxillary nerves into sphenoid sinus were also significant (P < 0.001). Uncinate bulla and giant ethmoid bulla were found to be significantly associated with sinonasal mucosal diseases (P = 0.004 and P = 0.002, respectively). CONCLUSION: Sinonasal region has a great number of variations, and some of them have been determined to be associated with sinonasal mucosal disease. It is necessary to know that some of these variations are associated with protrusion of significant structures such as carotid artery or optic nerve into the sinus and care should be observed in surgeries on patients carrying these variations. PMID:26834948

  15. Computed tomography study of pineal calcification in schizophrenia.

    PubMed

    Bersani, G; Garavini, A; Taddei, I; Tanfani, G; Nordio, M; Pancheri, P

    1999-06-01

    Computed tomography studies concerning pineal calcification (PC) in schizophrenia have been conducted mainly by one author who correlated this calcification with several aspects of the illness. On the basis of these findings the aim of the present study was to analyze size and incidence of pineal gland calcification by CT in schizophrenics and healthy controls, and to verify the relationship between pineal calcification and age, and the possible correlation with psychopathologic variables. Pineal calcification was measured on CT scans of 87 schizophrenics and 46 controls divided into seven age subgroups of five years each. No significant differences in PC incidence and mean size between patients and controls were observed as far as the entire group was considered. PC size correlated with age both in schizophrenics and controls. We found a higher incidence of PC in schizophrenics in the age subgroup of 21-25 years, and a negative correlation with positive symptoms of schizophrenia in the overall group. These findings could suggest a premature calcific process in schizophrenics and a probable association with 'non-paranoid' aspects of the illness. Nevertheless the potential role of this process possibly related to some aspects of the altered neurodevelopment in schizophrenia is still unclear. PMID:10572342

  16. Cone-beam computed tomography findings of impacted upper canines

    PubMed Central

    Bastos, Luana Costa; Oliveira-Santos, Christiano; da Silva, Silvio José Albergaria; Neves, Frederico Sampaio; Campos, Paulo Sérgio Flores

    2014-01-01

    Purpose To describe the features of impacted upper canines and their relationship with adjacent structures through three-dimensional cone-beam computed tomography (CBCT) images. Materials and Methods Using the CBCT scans of 79 upper impacted canines, we evaluated the following parameters: gender, unilateral/bilateral occurrence, location, presence and degree of root resorption of adjacent teeth (mild, moderate, or severe), root dilaceration, dental follicle width, and presence of other associated local conditions. Results Most of the impacted canines were observed in females (56 cases), unilaterally (51 cases), and at a palatine location (53 cases). Root resorption in adjacent teeth and root dilaceration were observed in 55 and 47 impacted canines, respectively. In most of the cases, the width of the dental follicle of the canine was normal; it was abnormally wide in 20 cases. A statistically significant association was observed for all variables, except for root dilaceration (p=0.115) and the side of impaction (p=0.260). Conclusion Root resorption of adjacent teeth was present in most cases of canine impaction, mostly affecting adjacent lateral incisors to a mild degree. A wide dental follicle of impacted canines was not associated with a higher incidence of external root resorption of adjacent teeth. PMID:25473636

  17. Review methods for image segmentation from computed tomography images

    SciTech Connect

    Mamat, Nurwahidah; Rahman, Wan Eny Zarina Wan Abdul; Soh, Shaharuddin Cik; Mahmud, Rozi

    2014-12-04

    Image segmentation is a challenging process in order to get the accuracy of segmentation, automation and robustness especially in medical images. There exist many segmentation methods that can be implemented to medical images but not all methods are suitable. For the medical purposes, the aims of image segmentation are to study the anatomical structure, identify the region of interest, measure tissue volume to measure growth of tumor and help in treatment planning prior to radiation therapy. In this paper, we present a review method for segmentation purposes using Computed Tomography (CT) images. CT images has their own characteristics that affect the ability to visualize anatomic structures and pathologic features such as blurring of the image and visual noise. The details about the methods, the goodness and the problem incurred in the methods will be defined and explained. It is necessary to know the suitable segmentation method in order to get accurate segmentation. This paper can be a guide to researcher to choose the suitable segmentation method especially in segmenting the images from CT scan.

  18. Nanoparticle Contrast Agents for Computed Tomography: A Focus on Micelles

    PubMed Central

    Cormode, David P.; Naha, Pratap C.; Fayad, Zahi A.

    2014-01-01

    Computed tomography (CT) is an X-ray based whole body imaging technique that is widely used in medicine. Clinically approved contrast agents for CT are iodinated small molecules or barium suspensions. Over the past seven years there has been a great increase in the development of nanoparticles as CT contrast agents. Nanoparticles have several advantages over small molecule CT contrast agents, such as long blood-pool residence times, and the potential for cell tracking and targeted imaging applications. Furthermore, there is a need for novel CT contrast agents, due to the growing population of renally impaired patients and patients hypersensitive to iodinated contrast. Micelles and lipoproteins, a micelle-related class of nanoparticle, have notably been adapted as CT contrast agents. In this review we discuss the principles of CT image formation and the generation of CT contrast. We discuss the progress in developing non-targeted, targeted and cell tracking nanoparticle CT contrast agents. We feature agents based on micelles and used in conjunction with spectral CT. The large contrast agent doses needed will necessitate careful toxicology studies prior to clinical translation. However, the field has seen tremendous advances in the past decade and we expect many more advances to come in the next decade. PMID:24470293

  19. Application of thermoacoustic computed tomography to breast imaging

    NASA Astrophysics Data System (ADS)

    Kruger, Robert A.; Kiser, William L., Jr.; Reinecke, Daniel R.; Kruger, Gabe A.

    1999-05-01

    Acoustic pressure waves are induced in soft tissue whenever time-varying radiation is absorbed. By recording these time- dependent pressure waves over a sufficient number of angles surrounding the tissue being imaged, it is possible to reconstruct the pattern of radiation absorption within the tissue in three dimensions with spatial resolution that is independent of the carrier frequency of the irradiating energy. We recently constructed the world's first thermoacoustic computed tomography (TACT) scanner, which exploits this physical interaction. Initial in vivo imaging of a human breast was performed using safe levels of 434 MHz radiation. Good soft tissue differentiation with 2 - 5 mm spatial resolution to a depth of 40 mm was achieved. The absorption properties of the breast and the irradiation pattern within the breast determined the TACT image contrast. The length of the RF pulse, the size of the transducers and their frequency response, the geometry of the detector array, and the reconstruction algorithm that was used determined the spatial resolution. We conclude that TACT imaging may have application to breast cancer detection.

  20. Angio computed tomography preoperative evaluation for anterolateral thigh flap harvesting.

    PubMed

    Ribuffo, Diego; Atzeni, Matteo; Saba, Luca; Milia, Arianna; Guerra, Maristella; Mallarini, Giorgio

    2009-04-01

    The vascular anatomy of the anterolateral thigh flap (ALTF) has many possible variations, and none of the currently used mapping techniques (eg, Echo Color Doppler) gives a thorough knowledge of all details. Among the last generation of angiographic diagnostic techniques, multi detector computed tomography, popularly known as Angio CT, has emerged as an outstanding noninvasive operator independent option, and has been described for deep inferior epigastric perforator and pedicled transverse rectus abdominis muscle planning. This study was conducted to evaluate its usefulness prior to ALTF harvesting.Nine consecutive patients were considered for oral or lower extremity reconstruction with the ALTF. After written informed consent was obtained from all patients, a preoperative Angio-CT study was performed for surgical planning. Accurate identification of septocutaneous or musculocutaneous perforator vessels was achieved and their location, course, and anatomic variations were reported and influenced surgery. Angio CT allows a complete vascular study of the donor area of the ALTF and evaluation of the best perforator vessels before surgery allows surgeons to get an ideal planning of the flap. This imaging method is currently proposed to every patient undergoing ALT flap reconstruction. PMID:19325338

  1. Artifact reduction in industrial computed tomography via data fusion

    SciTech Connect

    Schrapp, Michael; Goldammer, Matthias; Stephan, Jürgen

    2014-02-18

    As the most stressed part of a gas turbine the first row of turbine blades is not only a challenge for the materials used. Also the testing of these parts have to meet the highest standards. Computed tomography (CT) as the technique which could reveal the most details also provides the biggest challenges [1]: A full penetration of large sized turbine blades is often only possible at high X-ray voltages causing disproportional high costs. A reduction of the X-ray voltage is able to reduce these arising costs but yields non penetration artifacts in the reconstructed CT image. In most instances, these artifacts manifests itself as blurred and smeared regions at concave edges due to a reduced signal to noise ratio. In order to complement the missing information and to increase the overall image quality of our reconstruction, we use further imaging modalities such as a 3-D Scanner and ultrasonic imaging. A 3-D scanner is easy and cost effective to implement and is able to acquire all relevant data simultaneously with the CT projections. If, however, the interior structure is of supplemental interest, an ultrasonic imaging method is additionally used. We consider this data as a priori knowledge to employ them in an iterative reconstruction. To do so, standard iterative reconstruction methods are modified to incorporate the a priori data in a regularization approach in combination with minimizing the total variation of our image. Applying this procedure on turbine blades, we are able to reduce the apparent artifacts almost completely.

  2. Serial computed tomography scanning in acute pancreatitis: a prospective study.

    PubMed Central

    London, N J; Neoptolemos, J P; Lavelle, J; Bailey, I; James, D

    1989-01-01

    One hundred and two patients with acute pancreatitis had abdominal computed tomography (CT) scans within 72 hours of admission, at one week and at six weeks. Twenty eight attacks were clinically severe, 74 clinically mild. Ninety three (91%) admission scans, 85 (84%) one week scans, and 52 (51%) six week scans were abnormal. The aetiology of the pancreatitis could be inferred from 28 (27%) of admission scans, the CT sign of fatty liver having a sensitivity of 21% and specificity of 100% for alcoholic aetiology. The sensitivity of CT for gall stone aetiology was 34%, specificity 100%. The pancreatic size indices (max anteroposterior measurement of head x max anteroposterior measurement of body) of those patients with severe attacks were significantly greater than those with mild attacks on admission, at one week and at six weeks (p less than 0.004). Fourteen pseudocysts were detected by CT, five (36%) of which were clinically apparent. The pseudocyst size indices (max anteroposterior x max transverse measurement) of the pseudocysts which were clinically apparent were significantly greater than those which were not apparent (p less than 0.01) and only those pseudocysts with a size index greater than or equal to 15 cm2 required treatment. PMID:2651228

  3. Proceedings of clinical SPECT (single photon emission computed tomography) symposium

    SciTech Connect

    Not Available

    1986-09-01

    It has been five years since the last in-depth American College of Nuclear Physicians/Society of Nuclear Medicine Symposium on the subject of single photon emission computed tomography (SPECT) was held. Because this subject was nominated as the single most desired topic we have selected SPECT imaging as the basis for this year's program. The objectives of this symposium are to survey the progress of SPECT clinical applications that have taken place over the last five years and to provide practical and timely guidelines to users of SPECT so that this exciting imaging modality can be fully integrated into the evaluation of pathologic processes. The first half was devoted to a consideration of technical factors important in SPECT acquisition and the second half was devoted to those organ systems about which sufficient clinical SPECT imaging data are available. With respect to the technical aspect of the program we have selected the key areas which demand awareness and attention in order to make SPECT operational in clinical practice. These include selection of equipment, details of uniformity correction, utilization of phantoms for equipment acceptance and quality assurance, the major aspect of algorithms, an understanding of filtered back projection and appropriate choice of filters and an awareness of the most commonly generated artifacts and how to recognize them. With respect to the acquisition and interpretation of organ images, the faculty will present information on the major aspects of hepatic, brain, cardiac, skeletal, and immunologic imaging techniques. Individual papers are processed separately for the data base. (TEM)

  4. Quantitative Computed Tomography and Image Analysis for Advanced Muscle Assessment

    PubMed Central

    Edmunds, Kyle Joseph; Gíslason, Magnus K.; Arnadottir, Iris D.; Marcante, Andrea; Piccione, Francesco; Gargiulo, Paolo

    2016-01-01

    Medical imaging is of particular interest in the field of translational myology, as extant literature describes the utilization of a wide variety of techniques to non-invasively recapitulate and quantity various internal and external tissue morphologies. In the clinical context, medical imaging remains a vital tool for diagnostics and investigative assessment. This review outlines the results from several investigations on the use of computed tomography (CT) and image analysis techniques to assess muscle conditions and degenerative process due to aging or pathological conditions. Herein, we detail the acquisition of spiral CT images and the use of advanced image analysis tools to characterize muscles in 2D and 3D. Results from these studies recapitulate changes in tissue composition within muscles, as visualized by the association of tissue types to specified Hounsfield Unit (HU) values for fat, loose connective tissue or atrophic muscle, and normal muscle, including fascia and tendon. We show how results from these analyses can be presented as both average HU values and compositions with respect to total muscle volumes, demonstrating the reliability of these tools to monitor, assess and characterize muscle degeneration. PMID:27478562

  5. Motion artifact detection in four-dimensional computed tomography images

    NASA Astrophysics Data System (ADS)

    Bouilhol, G.; Ayadi, M.; Pinho, R.; Rit, S.; Sarrut, D.

    2014-03-01

    Motion artifacts appear in four-dimensional computed tomography (4DCT) images because of suboptimal acquisition parameters or patient breathing irregularities. Frequency of motion artifacts is high and they may introduce errors in radiation therapy treatment planning. Motion artifact detection can be useful for image quality assessment and 4D reconstruction improvement but manual detection in many images is a tedious process. We propose a novel method to evaluate the quality of 4DCT images by automatic detection of motion artifacts. The method was used to evaluate the impact of the optimization of acquisition parameters on image quality at our institute. 4DCT images of 114 lung cancer patients were analyzed. Acquisitions were performed with a rotation period of 0.5 seconds and a pitch of 0.1 (74 patients) or 0.081 (40 patients). A sensitivity of 0.70 and a specificity of 0.97 were observed. End-exhale phases were less prone to motion artifacts. In phases where motion speed is high, the number of detected artifacts was systematically reduced with a pitch of 0.081 instead of 0.1 and the mean reduction was 0.79. The increase of the number of patients with no artifact detected was statistically significant for the 10%, 70% and 80% respiratory phases, indicating a substantial image quality improvement.

  6. A framework of modeling detector systems for computed tomography simulations

    NASA Astrophysics Data System (ADS)

    Youn, H.; Kim, D.; Kim, S. H.; Kam, S.; Jeon, H.; Nam, J.; Kim, H. K.

    2016-01-01

    Ultimate development in computed tomography (CT) technology may be a system that can provide images with excellent lesion conspicuity with the patient dose as low as possible. Imaging simulation tools have been cost-effectively used for these developments and will continue. For a more accurate and realistic imaging simulation, the signal and noise propagation through a CT detector system has been modeled in this study using the cascaded linear-systems theory. The simulation results are validated in comparisons with the measured results using a laboratory flat-panel micro-CT system. Although the image noise obtained from the simulations at higher exposures is slightly smaller than that obtained from the measurements, the difference between them is reasonably acceptable. According to the simulation results for various exposure levels and additive electronic noise levels, x-ray quantum noise is more dominant than the additive electronic noise. The framework of modeling a CT detector system suggested in this study will be helpful for the development of an accurate and realistic projection simulation model.

  7. Bone marrow scintigraphy and computed tomography in myloproliferative disease

    SciTech Connect

    Goldsmith, S.J.; Gilbert, H.S.; Hermann, G.

    1985-05-01

    Peripheral bone marrow (BM) expansion in myeloproliferative disease (MPD) is demonstrated by scintigraphy (scint) with Technetium 99m sulfur colloid (TSC) or Indium III chloride (In). Computed tomography (CT) of the normal adult medullary cavity yields negative attenuation coefficients (AC) which become positive when BM fat is replaced. BM scint and CT of the medullary cavity are obtained in 23 studies in 21 pts: 6 polycythemia vera (PCV), 6 post PCV myeloid metaplasis (MyM), 4 agnogenic MyM, 3 myelodysplasia with refractory anemia, 1 acute myelocytic leukemia and 1 chronic myelocytic with acute leukemic transformation. AC were measured for BM cavity of lower extremities at each third of the femur and tibia. Values ranged from -89 to +289 Hounsfield units. The results are presented in this paper. There was agreement between SCINT and CT in 83% pts and segments. 80% of MB segments with + AC had scint identified BM. BM biopsy of the iliac crest demonstrated fibrosis or blast proliferation in pts with +AC rather than hypercellularity or osteosclerosis. The highest AC values (>200) were seen in pts with blast proliferation and fibrosis. Decreased BM scint visualization and +CT AC correlated with BM fibrosis and may reflect replacement of BM elements or decreased RES function. BM scint and CT are useful to monitor MPD and select BM sites for biopsy.

  8. Clinical significance of computed tomography assessment for third molar surgery.

    PubMed

    Nakamori, Kenji; Tomihara, Kei; Noguchi, Makoto

    2014-07-28

    Surgical extraction of the third molar is the most commonly performed surgical procedure in the clinical practice of oral surgery. Third molar surgery is warranted when there is inadequate space for eruption, malpositioning, or risk for cyst or odontogenic tumor formation. Preoperative assessment should include a detailed morphologic analysis of the third molar and its relationship to adjacent structures and surrounding tissues. Due to developments in medical engineering technology, computed tomography (CT) now plays a critical role in providing the clear images required for adequate assessment prior to third molar surgery. Removal of the maxillary third molar is associated with a risk for maxillary sinus perforation, whereas removal of the mandibular third molar can put patients at risk for a neurosensory deficit from damage to the lingual nerve or inferior alveolar nerve. Multiple factors, including demographic, anatomic, and treatment-related factors, influence the incidence of nerve injury during or following removal of the third molar. CT assessment of the third molar prior to surgery can identify some of these risk factors, such as the absence of cortication between the mandibular third molar and the inferior alveolar canal, prior to surgery to reduce the risk for nerve damage. This topic highlight presents an overview of the clinical significance of CT assessment in third molar surgery. PMID:25071882

  9. Clinical significance of computed tomography assessment for third molar surgery

    PubMed Central

    Nakamori, Kenji; Tomihara, Kei; Noguchi, Makoto

    2014-01-01

    Surgical extraction of the third molar is the most commonly performed surgical procedure in the clinical practice of oral surgery. Third molar surgery is warranted when there is inadequate space for eruption, malpositioning, or risk for cyst or odontogenic tumor formation. Preoperative assessment should include a detailed morphologic analysis of the third molar and its relationship to adjacent structures and surrounding tissues. Due to developments in medical engineering technology, computed tomography (CT) now plays a critical role in providing the clear images required for adequate assessment prior to third molar surgery. Removal of the maxillary third molar is associated with a risk for maxillary sinus perforation, whereas removal of the mandibular third molar can put patients at risk for a neurosensory deficit from damage to the lingual nerve or inferior alveolar nerve. Multiple factors, including demographic, anatomic, and treatment-related factors, influence the incidence of nerve injury during or following removal of the third molar. CT assessment of the third molar prior to surgery can identify some of these risk factors, such as the absence of cortication between the mandibular third molar and the inferior alveolar canal, prior to surgery to reduce the risk for nerve damage. This topic highlight presents an overview of the clinical significance of CT assessment in third molar surgery. PMID:25071882

  10. Dimensional Control of Micro Components with Synchrotron Computed Tomography

    SciTech Connect

    Ehrig, Karsten; Goebbels, Juergen; Staude, Andreas; Bartscher, Markus; Haertig, Frank; Kniel, Karin; Neukamm, Marko; Neuschaefer-Rube, Ulrich

    2010-04-06

    An advantage of Computed Tomography (CT) is the coordinate measurement capability of small inner structures, which are not accessible with classical measurement techniques. Using the advantages of synchrotron radiation CT measurements of parts with sizes of a few millimeters are performed at BAMline of BESSY II and are expected to be used as references for further dimensional measurements with micro CT. Previous investigations were focused on external gears, which are accessible with standard Coordinate Measurement Machines (CMMs). To obtain information about the accuracy of dimensional measurements of internal gears with CT, reference data have been measured by a tactile-optical CMM. This information is used to evaluate the performance of the CT. In addition to the first results for the evaluation of internal gear flanks, new measurements of different gear materials (steel and zirconium dioxide) will be presented. For functional evaluation, gear flanks are a matter of particular interest. Form deviations are analyzed with respect to the different gear materials to establish CT measurements as technology in the field of quality assurance and to compare the different manufacturing processes.

  11. RADIATION DOSE IN PAEDIATRIC COMPUTED TOMOGRAPHY: RISKS AND BENEFITS

    PubMed Central

    Ogbole, G.I.

    2010-01-01

    Computed tomography (CT) is a powerful tool for the accurate and effective diagnosis and treatment of a variety of conditions because it allows high-resolution three-dimensional images to be acquired very quickly. However as the number of CT procedures performed globally have continued to increase; with growing concerns about patient protection. Currently, no system is in place to track patient doses and the lifetime cumulative dose from medical sources. The widespread use of CT even in developing countries has raised questions regarding the possible threat to public health especially in children. The best available risk estimates suggest that paediatric CT will result in significantly increased lifetime radiation risk over adult CT. Studies have shown that lower milliampere-second (mAs) settings can be used for children without significant loss of information. Although the risk–benefit balance is still strongly tilted toward benefit, there is still need for caution. Furthermore since the frequency of paediatric CT examinations is rapidly increasing, and estimates suggest that quantitative lifetime radiation risks for children are not negligible, efforts should be made toward more active reduction of CT exposure settings in paediatric patients. This article hopes to address this concerns and draw attention to the fact that children are not ‘small adults ’ and should therefore be treated differently. PMID:25161479

  12. Determination of dosimetric quantities in pediatric abdominal computed tomography scans*

    PubMed Central

    Jornada, Tiago da Silva; da Silva, Teógenes Augusto

    2014-01-01

    Objective Aiming at contributing to the knowledge on doses in computed tomography (CT), this study has the objective of determining dosimetric quantities associated with pediatric abdominal CT scans, comparing the data with diagnostic reference levels (DRL). Materials and methods The study was developed with a Toshiba Asteion single-slice CT scanner and a GE BrightSpeed multi-slice CT unit in two hospitals. Measurements were performed with a pencil-type ionization chamber and a 16 cm-diameter polymethylmethacrylate trunk phantom. Results No significant difference was observed in the values for weighted air kerma index (CW), but the differences were relevant in values for volumetric air kerma index (CVOL), air kerma-length product (PKL,CT) and effective dose. Conclusion Only the CW values were lower than the DRL, suggesting that dose optimization might not be necessary. However, PKL,CT and effective dose values stressed that there still is room for reducing pediatric radiation doses. The present study emphasizes the importance of determining all dosimetric quantities associated with CT scans. PMID:25741103

  13. Brain single photon emission computed tomography in neonates

    SciTech Connect

    Denays, R.; Van Pachterbeke, T.; Tondeur, M.; Spehl, M.; Toppet, V.; Ham, H.; Piepsz, A.; Rubinstein, M.; Nol, P.H.; Haumont, D. )

    1989-08-01

    This study was designed to rate the clinical value of ({sup 123}I)iodoamphetamine (IMP) or ({sup 99m}Tc) hexamethyl propylene amine oxyme (HM-PAO) brain single photon emission computed tomography (SPECT) in neonates, especially in those likely to develop cerebral palsy. The results showed that SPECT abnormalities were congruent in most cases with structural lesions demonstrated by ultrasonography. However, mild bilateral ventricular dilatation and bilateral subependymal porencephalic cysts diagnosed by ultrasound were not associated with an abnormal SPECT finding. In contrast, some cortical periventricular and sylvian lesions and all the parasagittal lesions well visualized in SPECT studies were not diagnosed by ultrasound scans. In neonates with subependymal and/or intraventricular hemorrhage the existence of a parenchymal abnormality was only diagnosed by SPECT. These results indicate that ({sup 123}I)IMP or ({sup 99m}Tc)HM-PAO brain SPECT shows a potential clinical value as the neurodevelopmental outcome is clearly related to the site, the extent, and the number of cerebral lesions. Long-term clinical follow-up is, however, mandatory in order to define which SPECT abnormality is associated with neurologic deficit.

  14. The Status Of Quality Assurance For Computed Tomography Systems

    NASA Astrophysics Data System (ADS)

    McCrohan, J. L.; Showalter, C. K.; Burkhart, R. L.; Shuman, F. G. D.

    1983-12-01

    The benefits of a comprehensive quality assurance (QA) program in conventional diagnostic radiology are well understood. In computed tomography (CT), however, the situation is less clear. Since the advent of CT a number of manufacturers and individual medical physicists have recommended a variety of parameters for periodic monitoring or system performance evaluation. These recommendations are reviewed. There are no data, however, indicating that CT facilities, with the exception of some mobile units, have implemented a comprehensive QA program, including the daily collection of data and its interpretation and application to the identification and correction of problems with the CT system. Data from a nationwide study will be presented which describe the present status of QA CT facilities. QA programs on mobile CT systems, where there is more concern about consistent system performance due to the effects of moving the unit, have suggested that trends in performance can be identified. Preliminary data indicates that a similar situation may hold in the case of fixed facilities. This suggests that CT QA programs may permit detection of problems before they significantly affect the diagnostic value of the CT image. The recent development of automated CT QA software by a number of investigators will also facilitate the implementation of appropriate QA protocols.

  15. Ultrasound attenuation computed tomography assessment of PAGAT gel dose

    NASA Astrophysics Data System (ADS)

    Khoei, S.; Trapp, J. V.; Langton, C. M.

    2014-08-01

    Ultrasound has been previously investigated as an alternative readout method for irradiated polymer gel dosimeters, with authors reporting varying dose responses. We extend previous work utilizing a new computed tomography ultrasound scanner comprising of two identical 5 MHz, 128-element linear-array ultrasound transducers, co-axially aligned and submerged in water as a coupling agent, with rotational of the gel dosimeter between the transducers facilitated by a robotic arm. We have investigated the dose-dependence of both ultrasound bulk attenuation and broadband ultrasound attenuation (BUA) for the PAGAT gel dosimeter. The ultrasound bulk attenuation dose sensitivity was found to be 1.46  ±  0.04 dB m -1 Gy -1, being in agreement with previously published results for PAG and MAGIC gels. BUA was also found to be dose dependent and was measured to be 0.024  ±  0.003 dB MHz -1 Gy -1 the advantage of BUA being its insensitivity to frequency-independent attenuation mechanisms including reflection and refraction, thereby minimizing image reconstruction artefacts.

  16. Computed Tomography Enterography for Evaluation of Inflammatory Bowel Disease

    PubMed Central

    Park, Min Jung

    2013-01-01

    Computed tomography enterography (CTE) has become a main modality for the evaluation of inflammatory bowel disease (IBD). It simultaneously offers visualization of the small bowel and extraintestinal status, which is helpful for diagnosing IBD. Crohn disease has long segmental enhancing wall thickening related with the eccentric longitudinal distribution. In addition, mural stratification, fibrofatty proliferation, positive comb sign by increased mesenteric vascularity and internal/perianal fistula are characteristics of Crohn disease and can be identified on CTE. Short segmental inflammatory wall thickening and the central low attenuated lymph nodes are favorable CT finding of intestinal tuberculosis. A geographic, relatively large, and deep penetrating ulcer with bowel wall thickening and mural hyperenhancement in ileocecal area are characteristics of intestinal Behcet disease. Each of CTE findings for the IBDs is helpful for differential diagnosis. The main disadvantage of this technique is the requisite radiation exposure of patients, particularly in young patients. However, recent development of advanced CT techniques is promising for radiation dose reduction without compromising diagnostic image quality. PMID:23964329

  17. Noninvasive coronary artery angiography using electron beam computed tomography

    NASA Astrophysics Data System (ADS)

    Rumberger, John A.; Rensing, Benno J.; Reed, Judd E.; Ritman, Erik L.; Sheedy, Patrick F., II

    1996-04-01

    Electron beam computed tomography (EBCT), also known as ultrafast-CT or cine-CT, uses a unique scanning architecture which allows for multiple high spatial resolution electrocardiographic triggered images of the beating heart. A recent study has demonstrated the feasibility of qualitative comparisons between EBCT derived 3D coronary angiograms and invasive angiography. Stenoses of the proximal portions of the left anterior descending and right coronary arteries were readily identified, but description of atherosclerotic narrowing in the left circumflex artery (and distal epicardial disease) was not possible with any degree of confidence. Although these preliminary studies support the notion that this approach has potential, the images overall were suboptimal for clinical application as an adjunct to invasive angiography. Furthermore, these studies did not examine different methods of EBCT scan acquisition, tomographic slice thicknesses, extent of scan overlap, or other segmentation, thresholding, and interpolation algorithms. Our laboratory has initiated investigation of these aspects and limitations of EBCT coronary angiography. Specific areas of research include defining effects of cardiac orientation; defining the effects of tomographic slice thickness and intensity (gradient) versus positional (shaped based) interpolation; and defining applicability of imaging each of the major epicardial coronary arteries for quantitative definition of vessel size, cross-sectional area, taper, and discrete vessel narrowing.

  18. Considerations on an automatic computed tomography tube current modulation system.

    PubMed

    Moro, Luca; Panizza, Denis; D'Ambrosio, Daniela; Carne, Irene

    2013-10-01

    The scope of this study was to evaluate the effects on radiation output and image noise varying the acquisition parameters with an automatic tube current modulation (ATCM) system in computed tomography (CT). Chest CT examinations of an anthropomorphic phantom were acquired using a GE LightSpeed VCT 64-slice tomograph. Acquisitions were performed using different pitch, slice thickness and noise index (NI) values and varying the orientation of the scanned projection radiograph (SPR). The radiation output was determined by the CT dose index (CTDIvol). Image noise was evaluated measuring the standard deviation of CT numbers in several regions of interest. The radiation output was lower if the SPR was acquired in the anterior-posterior projection. The radiation dose with the posterior-anterior SPR was higher, because the divergence of the X-ray beam magnifies the anatomical structures closest to the tube, especially the spinal column, and this leads the ATCM system to estimate higher patient attenuation values and, therefore, to select higher tube current values. The NI was inversely proportional to the square root of the CTDIvol and, with fixed NI, the CTDIvol increased as the slice thickness decreased. This study suggests some important issues to use the GE ATCM system efficiently.

  19. Dual-energy computed tomography for gout diagnosis and management.

    PubMed

    Dalbeth, Nicola; Choi, Hyon K

    2013-01-01

    The central feature of gout is deposition of monosodium urate crystals. Dual-energy computed tomography (DECT) is a recently developed advanced imaging method that enables visualisation of urate deposits by analysis of the chemical composition of the scanned materials. This review summarises recent research describing the use of DECT in gout management. This technology may assist in both diagnosis and monitoring of the disease. Studies of patients with established disease indicate diagnostic accuracy for gout is high. Excellent inter-reader agreement has been reported for detection of urate deposits by use of DECT. Automated volume assessment software also enables rapid and reproducible measurement of urate deposits within tophi, suggesting that this modality may be useful for monitoring the disease. Although several case reports indicate DECT can be used to reveal reduction in the size of urate deposits, the sensitivity to change in response to urate-lowering therapy has not yet been systematically reported. DECT images reveal variable urate deposition within tophi of the same physical size. The ability to visualise urate deposits in tissue may provide new insights into the pathology and mechanisms of gout.

  20. Corrosion monitoring with tangential radiography and limited view computed tomography

    NASA Astrophysics Data System (ADS)

    Ewert, Uwe; Tschaikner, Martin; Hohendorf, Stefan; Bellon, Carsten; Haith, Misty I.; Huthwaite, Peter; Lowe, Michael J. S.

    2016-02-01

    Accurate and reliable detection of subsea pipeline corrosion is required in order to verify the integrity of the pipeline. A laboratory trial was conducted with a representative pipe sample. The accurate measurement of the wall thickness and corrosion was performed with high energy X-rays and a digital detector array. A 7.5 MV betatron was used to penetrate a stepped pipe and a welded test pipe of 3 m length and 327 mm outer diameter, with different artificial corrosion areas in the 24 mm thick steel wall. The radiographs were taken with a 40 x 40 cm² digital detector array, which was not large enough to cover the complete pipe diameter after magnification. A C-arm based geometry was tested to evaluate the potential for automated inspection in field. The primary goal was the accurate measurement of wall thickness conforming to the standard. The same geometry was used to explore the ability of a C-arm based scanner in asymmetric mode for computed tomography (CT) measurement, taking projections covering only two thirds of the pipe diameter. The technique was optimized with the modelling software aRTist. A full volume of the pipe was reconstructed and the CT data set was used for reverse engineering, providing a CAD file for further aRTist simulations to explore the technique for subsea inspections.