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Sample records for tomography showed multiple

  1. Multiple Scattering Tomography

    NASA Astrophysics Data System (ADS)

    Modregger, Peter; Kagias, Matias; Peter, Silvia; Abis, Matteo; Guzenko, Vitaliy A.; David, Christian; Stampanoni, Marco

    2014-07-01

    Multiple scattering represents a challenge for numerous modern tomographic imaging techniques. In this Letter, we derive an appropriate line integral that allows for the tomographic reconstruction of angular resolved scattering distributions, even in the presence of multiple scattering. The line integral is applicable to a wide range of imaging techniques utilizing various kinds of probes. Here, we use x-ray grating interferometry to experimentally validate the framework and to demonstrate additional structural sensitivity, which exemplifies the impact of multiple scattering tomography.

  2. Olaparib shows promise in multiple tumor types.

    PubMed

    2013-07-01

    A phase II study of the PARP inhibitor olaparib (AstraZeneca) for cancer patients with inherited BRCA1 and BRCA2 gene mutations confirmed earlier results showing clinical benefit for advanced breast and ovarian cancers, and demonstrated evidence of effectiveness against pancreatic and prostate cancers. PMID:23847380

  3. Dermascope guided multiple reference optical coherence tomography.

    PubMed

    Dsouza, Roshan; Subhash, Hrebesh; Neuhaus, Kai; Hogan, Josh; Wilson, Carol; Leahy, Martin

    2014-09-01

    In this paper, we report the feasibility of integrating a novel low cost optical coherence tomography (OCT) system with a dermascope for point-of-care applications. The proposed OCT system is based on an enhanced time-domain optical coherence tomographic system, called multiple reference OCT (MR-OCT), which uses a single miniature voice coil actuator and a partial mirror for extending the axial scan range. The system can simultaneously register both the superficial dermascope image and the depth-resolved OCT sub-surface information by an interactive beam steering method. A practitioner is able to obtain the depth resolved information of the point of interest by simply using the mouse cursor. The proposed approach of combining a dermascope with a low cost OCT provides a unique powerful optical imaging modality for a range of dermatological applications. Hand-held dermascopic OCT devices would also enable point of care and remote health monitoring. PMID:25401004

  4. Dermascope guided multiple reference optical coherence tomography

    PubMed Central

    Dsouza, Roshan; Subhash, Hrebesh; Neuhaus, Kai; Hogan, Josh; Wilson, Carol; Leahy, Martin

    2014-01-01

    In this paper, we report the feasibility of integrating a novel low cost optical coherence tomography (OCT) system with a dermascope for point-of-care applications. The proposed OCT system is based on an enhanced time-domain optical coherence tomographic system, called multiple reference OCT (MR-OCT), which uses a single miniature voice coil actuator and a partial mirror for extending the axial scan range. The system can simultaneously register both the superficial dermascope image and the depth-resolved OCT sub-surface information by an interactive beam steering method. A practitioner is able to obtain the depth resolved information of the point of interest by simply using the mouse cursor. The proposed approach of combining a dermascope with a low cost OCT provides a unique powerful optical imaging modality for a range of dermatological applications. Hand-held dermascopic OCT devices would also enable point of care and remote health monitoring. PMID:25401004

  5. Heavy Coffee Drinkers Show Lower Risk of Multiple Sclerosis

    MedlinePLUS

    ... nih.gov/medlineplus/news/fullstory_157582.html Heavy Coffee Drinkers Show Lower Risk of Multiple Sclerosis But ... HealthDay News) -- People who drink a lot of coffee may have a lower risk of developing multiple ...

  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. Oblique view of the southwest side showing multiple roof planes. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Oblique view of the southwest side showing multiple roof planes. View facing northeast - U.S. Naval Base, Pearl Harbor, Foundry, Seventh Street near Avenue F intersection, Pearl City, Honolulu County, HI

  8. FEATURE 3, LARGE GUN POSITION, SHOWING MULTIPLE COMPARTMENTS, VIEW FACING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FEATURE 3, LARGE GUN POSITION, SHOWING MULTIPLE COMPARTMENTS, VIEW FACING SOUTH. - Naval Air Station Barbers Point, Anti-Aircraft Battery Complex-Large Gun Position, East of Coral Sea Road, northwest of Hamilton Road, Ewa, Honolulu County, HI

  9. View of southern quarry wall, facing west, showing multiple drill ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of southern quarry wall, facing west, showing multiple drill holes on face - Granite Hill Plantation, Quarry No. 4, South side of State Route 16, 1.3 miles northeast east of Sparta, Sparta, Hancock County, GA

  10. 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.

  11. 7. SOUTHEAST VIEW OF BIG DALTON DAM SHOWING THE MULTIPLE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. SOUTHEAST VIEW OF BIG DALTON DAM SHOWING THE MULTIPLE ARCHES, AN UPSTREAM VIEW OF THE PARAPET WALL ALONG THE CREST OF THE DAM, AND THE SHELTER HOUSE AT THE EAST END OF THE DAM. - Big Dalton Dam, 2600 Big Dalton Canyon Road, Glendora, Los Angeles County, CA

  12. FEATURE 3, LARGE GUN POSITION, SHOWING MULTIPLE COMPARTMENTS, VIEW FACING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FEATURE 3, LARGE GUN POSITION, SHOWING MULTIPLE COMPARTMENTS, VIEW FACING SOUTH (with scale stick). - Naval Air Station Barbers Point, Anti-Aircraft Battery Complex-Large Gun Position, East of Coral Sea Road, northwest of Hamilton Road, Ewa, Honolulu County, HI

  13. FIVE KEPLER TARGET STARS THAT SHOW MULTIPLE TRANSITING EXOPLANET CANDIDATES

    SciTech Connect

    Steffen, Jason H.; Batalha, Natalie M.; Borucki, William J.; Caldwell, Douglas A.; Haas, Michael J.; Jenkins, Jon M.; Koch, David; Lissauer, Jack J.; Buchhave, Lars A.; Fabrycky, Daniel C.; Fressin, Francois; Holman, Matthew J.; Latham, David W.; Cochran, William D.; Endl, Michael; Ford, Eric B.; Moorhead, Althea V.; Fortney, Jonathan J.; Howell, Steve B.; Isaacson, Howard

    2010-12-10

    We present and discuss five candidate exoplanetary systems identified with the Kepler spacecraft. These five systems show transits from multiple exoplanet candidates. Should these objects prove to be planetary in nature, then these five systems open new opportunities for the field of exoplanets and provide new insights into the formation and dynamical evolution of planetary systems. We discuss the methods used to identify multiple transiting objects from the Kepler photometry as well as the false-positive rejection methods that have been applied to these data. One system shows transits from three distinct objects while the remaining four systems show transits from two objects. Three systems have planet candidates that are near mean motion commensurabilities-two near 2:1 and one just outside 5:2. We discuss the implications that multi-transiting systems have on the distribution of orbital inclinations in planetary systems, and hence their dynamical histories, as well as their likely masses and chemical compositions. A Monte Carlo study indicates that, with additional data, most of these systems should exhibit detectable transit timing variations (TTVs) due to gravitational interactions, though none are apparent in these data. We also discuss new challenges that arise in TTV analyses due to the presence of more than two planets in a system.

  14. Five Kepler target stars that show multiple transiting exoplanet candidates

    SciTech Connect

    Steffen, Jason H.; Batalha, Natalie M.; Borucki, William J.; Buchhave, Lars A.; Caldwell, Douglas A.; Cochran, William D.; Endl, Michael; Fabrycky, Daniel C.; Fressin, Francois; Ford, Eric B.; Fortney, Jonathan J.

    2010-06-01

    We present and discuss five candidate exoplanetary systems identified with the Kepler spacecraft. These five systems show transits from multiple exoplanet candidates. Should these objects prove to be planetary in nature, then these five systems open new opportunities for the field of exoplanets and provide new insights into the formation and dynamical evolution of planetary systems. We discuss the methods used to identify multiple transiting objects from the Kepler photometry as well as the false-positive rejection methods that have been applied to these data. One system shows transits from three distinct objects while the remaining four systems show transits from two objects. Three systems have planet candidates that are near mean motion commensurabilities - two near 2:1 and one just outside 5:2. We discuss the implications that multitransiting systems have on the distribution of orbital inclinations in planetary systems, and hence their dynamical histories; as well as their likely masses and chemical compositions. A Monte Carlo study indicates that, with additional data, most of these systems should exhibit detectable transit timing variations (TTV) due to gravitational interactions - though none are apparent in these data. We also discuss new challenges that arise in TTV analyses due to the presence of more than two planets in a system.

  15. Multiple nontuberculous scrofulodermas showing dramatic response to clarithromycin

    PubMed Central

    Parimalam, Kumar; Senthil, G.; Vinnarasan, M.; Arumugakani, V.; Amutha, B. M.; Lalitha, S.; Swarna, S.

    2015-01-01

    Atypical mycobacteria are distinct from the Mycobacterium tuberculosis. Mycobacterium chelonae, a non-pigment producing rapid grower, can be found in many cutaneous sites; infection occurs most commonly after skin trauma from surgery, injections, or minor injuries. In immune competent patients, the infection is more frequently localized as a cellulitis or a nodule, whereas, in the immunocompromised patient, dissemination (more than five lesions) can occur. Because the organism is resistant to antituberculous therapy, abscess can develop and follow a chronic, indolent course. We report a case of multiple scrofuloderma due to nontuberculous infection caused by M. chelonae showing dramatic response to clarithromycin. PMID:25657914

  16. New World cattle show ancestry from multiple independent domestication events

    PubMed Central

    McTavish, Emily Jane; Decker, Jared E.; Schnabel, Robert D.; Taylor, Jeremy F.; Hillis, David M.

    2013-01-01

    Previous archeological and genetic research has shown that modern cattle breeds are descended from multiple independent domestication events of the wild aurochs (Bos primigenius) ∼10,000 y ago. Two primary areas of domestication in the Middle East/Europe and the Indian subcontinent resulted in taurine and indicine lines of cattle, respectively. American descendants of cattle brought by European explorers to the New World beginning in 1493 generally have been considered to belong to the taurine lineage. Our analyses of 47,506 single nucleotide polymorphisms show that these New World cattle breeds, as well as many related breeds of cattle in southern Europe, actually exhibit ancestry from both the taurine and indicine lineages. In this study, we show that, although European cattle are largely descended from the taurine lineage, gene flow from African cattle (partially of indicine origin) contributed substantial genomic components to both southern European cattle breeds and their New World descendants. New World cattle breeds, such as Texas Longhorns, provide an opportunity to study global population structure and domestication in cattle. Following their introduction into the Americas in the late 1400s, semiferal herds of cattle underwent between 80 and 200 generations of predominantly natural selection, as opposed to the human-mediated artificial selection of Old World breeding programs. Our analyses of global cattle breed population history show that the hybrid ancestry of New World breeds contributed genetic variation that likely facilitated the adaptation of these breeds to a novel environment. PMID:23530234

  17. New World cattle show ancestry from multiple independent domestication events.

    PubMed

    McTavish, Emily Jane; Decker, Jared E; Schnabel, Robert D; Taylor, Jeremy F; Hillis, David M

    2013-04-01

    Previous archeological and genetic research has shown that modern cattle breeds are descended from multiple independent domestication events of the wild aurochs (Bos primigenius) ∼10,000 y ago. Two primary areas of domestication in the Middle East/Europe and the Indian subcontinent resulted in taurine and indicine lines of cattle, respectively. American descendants of cattle brought by European explorers to the New World beginning in 1493 generally have been considered to belong to the taurine lineage. Our analyses of 47,506 single nucleotide polymorphisms show that these New World cattle breeds, as well as many related breeds of cattle in southern Europe, actually exhibit ancestry from both the taurine and indicine lineages. In this study, we show that, although European cattle are largely descended from the taurine lineage, gene flow from African cattle (partially of indicine origin) contributed substantial genomic components to both southern European cattle breeds and their New World descendants. New World cattle breeds, such as Texas Longhorns, provide an opportunity to study global population structure and domestication in cattle. Following their introduction into the Americas in the late 1400s, semiferal herds of cattle underwent between 80 and 200 generations of predominantly natural selection, as opposed to the human-mediated artificial selection of Old World breeding programs. Our analyses of global cattle breed population history show that the hybrid ancestry of New World breeds contributed genetic variation that likely facilitated the adaptation of these breeds to a novel environment. PMID:23530234

  18. Diffuse optical tomography based on multiple access coding

    NASA Astrophysics Data System (ADS)

    Wang, Xuefeng; Wang, Yuanqing; Su, Jinshan; Xu, Fan

    2016-04-01

    Diffuse optical tomography (DOT) has the advantages of being a non-invasive, non-radiation emitting and low-cost biological tissue imaging method, and many recent studies have employed this technology. By improving the spatial resolution and developing a new method for constantly improving the flexibility of the experimental device, the system can perform data acquisition rapidly and conveniently. We propose a method for rapid data acquisition based on multiple access coding; it can acquire data in parallel, and the system can greatly improve the temporal resolution of the data acquisition step in diffuse optical tomography thereafter. We simulate the encoding and decoding process of the source-detector pair and successfully isolate the source signal from mixed signals. The DOT image reconstruction highlight the effectiveness of the system.

  19. Optical Coherence Tomography to Assess Neurodegeneration in Multiple Sclerosis.

    PubMed

    Petzold, Axel

    2016-01-01

    Retinal spectral domain optical coherence tomography (OCT) has emerged as a clinical and research tool in multiple sclerosis (MS) and optic neuritis (ON). This chapter summarizes a short OCT protocol as included in international consensus guidelines. The protocol was written for hands-on style such that both clinicians and OCT technicians can make use of it. The protocol is suitable for imaging of the optic nerve head and macular regions as a baseline for follow-up investigations, individual layer segmentation, and diagnostic assessment. PMID:25476442

  20. Tropospheric wet refractivity tomography using multiplicative algebraic reconstruction technique

    NASA Astrophysics Data System (ADS)

    Xiaoying, Wang; Ziqiang, Dai; Enhong, Zhang; Fuyang, K. E.; Yunchang, Cao; Lianchun, Song

    2014-01-01

    Algebraic reconstruction techniques (ART) have been successfully used to reconstruct the total electron content (TEC) of the ionosphere and in recent years be tentatively used in tropospheric wet refractivity and water vapor tomography in the ground-based GNSS technology. The previous research on ART used in tropospheric water vapor tomography focused on the convergence and relaxation parameters for various algebraic reconstruction techniques and rarely discussed the impact of Gaussian constraints and initial field on the iteration results. The existing accuracy evaluation parameters calculated from slant wet delay can only evaluate the resultant precision of the voxels penetrated by slant paths and cannot evaluate that of the voxels not penetrated by any slant path. The paper proposes two new statistical parameters Bias and RMS, calculated from wet refractivity of the total voxels, to improve the deficiencies of existing evaluation parameters and then discusses the effect of the Gaussian constraints and initial field on the convergence and tomography results in multiplicative algebraic reconstruction technique (MART) to reconstruct the 4D tropospheric wet refractivity field using simulation method.

  1. Oblique WIng Research Aircraft multiple exposure showing wing rotation

    NASA Technical Reports Server (NTRS)

    1976-01-01

    In this 1976 composite photograph taken from above the Oblique Wing Research Aircraft, the rotation capability of the wing is illustrated. The multiple exposure illustrates the limits of wing rotation from 0 and 45 degrees, along with the area swept-out during a full rotation. The Oblique Wing Research Aircraft was a small, remotely piloted, research craft designed and flight tested to look at the aerodynamic characteristics of an oblique wing and the control laws necessary to achieve acceptable handling qualities. NASA Dryden Flight Research Center and the NASA Ames Research Center conducted research with this aircraft in the mid-1970s to investigate the feasibility of flying an oblique wing aircraft

  2. Multidetector computed tomography in the evaluation of hereditary multiple exostoses.

    PubMed

    Kwee, Robert M; Fayad, Laura M; Fishman, Elliot K; Fritz, Jan

    2016-02-01

    Hereditary multiple exostoses (HME) is an autosomal dominant disorder characterized by the formation of multiple osteochondromas. Because of its superior soft tissue contrast and absence of ionizing radiation, magnetic resonance imaging is the first choice imaging technique for the evaluation of complex lesions and complications related to HME. However, multidetector computed tomography (MDCT) also can be of value in the evaluation of patients with HME, which is reviewed in this article. Topics outlined are low-dose MDCT technique, 3-dimensional visualization techniques, typical MDCT appearances, differential diagnostic considerations, and the usefulness of MDCT in the assessment of emergent and non-emergent complications related to HME, among which spinal cord compression, pneumothorax and hematothorax, pseudoaneurysms, fractures, growth disturbances, chondrosarcoma transformation, and muscular and peripheral nerve involvement. PMID:26781144

  3. A computed tomography implementation of multiple-image radiography

    SciTech Connect

    Brankov, Jovan G.; Wernick, Miles N.; Yang Yongyi; Li Jun; Muehleman, Carol; Zhong Zhong; Anastasio, Mark A.

    2006-02-15

    Conventional x-ray computed tomography (CT) produces a single volumetric image that represents the spatially variant linear x-ray attenuation coefficient of an object. However, in many situations, differences in the x-ray attenuation properties of soft tissues are very small and difficult to measure in conventional x-ray imaging. In this work, we investigate an analyzer-based imaging method, called computed tomography multiple-image radiography (CT-MIR), which is a tomographic implementation of the recently proposed multiple-image radiography method. The CT-MIR method reconstructs concurrently three physical properties of the object. In addition to x-ray attenuation, CT-MIR produces volumetric images that represent the refraction and ultrasmall-angle scattering properties of the object. These three images can provide a rich description of the object's physical properties that are revealed by the probing x-ray beam. An imaging model for CT-MIR that is based on the x-ray transform of the object properties is established. The CT-MIR method is demonstrated by use of experimental data acquired at a synchroton radiation imaging beamline, and is compared to the pre-existing diffraction-enhanced imaging CT method. We also investigate the merit of an iterative reconstruction method for use with future clinical implementations of CT-MIR, which we anticipate would be photon limited.

  4. Single vs. Multiple Transponders for Radio Tomography of Asteroids

    NASA Astrophysics Data System (ADS)

    Pursiainen, Sampsa; Kaasalainen, M.; TUT Inverse Problems Group led by Mikko Kaasalainen, Prof.

    2013-10-01

    The purpose of this study was to develop numerical inverse methods for radio tomography of asteroids in which the goal is to recover the internal electric permittivity distribution of an asteroid based on radio frequency data gathered by an orbiter. The present tomography approach with a single transponder has been utilized in the CONSERT experiment which aims at reconstruction of a comet nucleus structure as a part of the ROSETTA (comet rendezvous) mission. This study aims at progress in designing the coming missions which necessitates a through investigation of implementable data gathering setups as well as forward (data) simulation and inverse computation schemes. The current signal generation approach of utilizing multiple transponders provides one potential scenario which can even be essential to achieve an appropriate reconstruction quality. Research to find the simplest and most robust (best bang for the buck) scenarios for signal generation and measurements is of utmost importance due to the high cost and long duration of planning and implementing a space mission, necessitating a highly optimized payload. Regarding the forward and inverse approaches, this study, in particular, validated the iterative alternating sequential (IAS) inversion (reconstruction) strategy with a forward simulation relying on the wave equation of the electric potential. To enable the IAS inverse approach, a linearized forward model was utilized to find the reconstructions. The inverse problem was given a Bayesian formulation. The numerical experiments included in this study compared the single and multiple transponder signal generation approaches in localization of permittivity anomalies. Three different anomaly strengths and four levels of total noise were tested to examine the tolerance of present reconstruction strategy to different error sources. Noise due to forward simulation was estimated. The results obtained were promising regarding the combination of the current forward and inverse approaches. They suggest that reconstruction quality increases along with the number of transponders and that multiple transponders can be necessary to distinguish three separate anomalies.

  5. Computed tomography of deep fat masses in multiple symmetrical lipomatosis

    SciTech Connect

    Enzi, G.; Biondetti, P.R.; Fiore, D.; Mazzoleni, F.

    1982-07-01

    Deep fat masses were evaluated by computed tomography (CT) in 15 patients with multiple symmetrical lipomatosis. In 4 patients, peritracheal accumulations of fat were observed. In 3 of them, tracheal compression by lipomatous tissue was demonstrated: 2 were asymptomatic and the third severe respiratory insufficiency secondary to blockage of the air was by the vocal cords as the result of recurrent nerve palsy. In 6 patients, lipomatous tissue occupied the potential space between the spina scapulae and the trapezius, supraspinatus, and infraspinatus muscles. In 2, calcification of lipomatous masses was observed. There was no relationship between extension of subcutaneous fat and accumulation at deep sites. CT facilitates early detection of peritracheal lipomatous tissue and is helpful in follow-up when deep fat accumulation is responsible for space-occupying lesions requiring surgery.

  6. Multiple delay lines full-field optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Wang, Jingyu; Dainty, Christopher; Podoleanu, Adrian G.

    2008-09-01

    Full-field Optical Coherence Tomography (FF-OCT) is a parallel detection OCT technique using a 2D detector array. This technique avoids mechanical scanning in imaging optics. Therefore, it can speed up the imaging process and enhance the imaging quality. We present a FF-OCT instrument to be used in conjunction with the principle of multiple delays (MD) OCT to evaluate the topography of curved objects in a single-shot imaging. We evaluate the optimum combination of the MD principle with the FF-OCT method and measure the radius of a metal ball with this method. We managed to obtain 2n-1 contour lines using an MDE with n delays in a single en-face OCT image to evaluate the curvature of the object surface.

  7. Multiple myeloma presenting as plasmacytoma of the jaws showing prominent bone formation during chemotherapy

    PubMed Central

    An, S-Y; An, C-H; Choi, K-S; Heo, M-S

    2013-01-01

    A 65-year-old female visited our hospital complaining of a swelling on the left cheek area of 2 years' duration. A panoramic radiograph revealed an ill-defined osteolytic radiolucent bony lesion involving the left mandibular angle, ascending ramus, coronoid process and condylar process. Histological examination showed the mandibular lesion to be a plasmacytoma, and a systemic work-up was obtained to rule out multiple myeloma. Contrast-enhanced CT images showed a well-defined and slightly enhanced round mass on the left ramal area, accompanied by the destruction of the left ramus and posterior maxilla. An 18F-fluorodeoxy-glucose positron emission tomography CT (18F-FDG PET/CT) scan revealed a hypermetabolic mass extending from the left mandible to the left maxillary sinus. The patient had M-protein in serum and urine, plasma cells up to 36.5% on bone marrow biopsy and anaemia as a clinical complication. The patient was diagnosed with multiple myeloma and received chemotherapy with thalidomide, cyclophosphamide and dexamethasone. A PET/CT scan taken 6 months later revealed that the hypermetabolic mass had disappeared and there was remarkable bone formation on the left mandible compared with a previous PET/CT scan. A panoramic radiograph taken 8 months later also demonstrated a prominent bone formation of the affected site. To the best of our knowledge, the current case is the first report of multiple myeloma presenting as plasmacytoma of the mandible with an FDG PET/CT scan. The lesion was solitary at diagnosis, and remarkable bone formation was newly observed on the radiographic examination during chemotherapy. PMID:23520399

  8. Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle

    NASA Astrophysics Data System (ADS)

    Foulger, G. R.; Pritchard, M. J.; Julian, B. R.; Evans, J. R.; Allen, R. M.; Nolet, G.; Morgan, W. J.; Bergsson, B. H.; Erlendsson, P.; Jakobsdottir, S.; Ragnarsson, S.; Stefansson, R.; Vogfjrd, K.

    2001-08-01

    We report the results of the highest-resolution teleseismic tomography study yet performed of the upper mantle beneath Iceland. The experiment used data gathered by the Iceland Hotspot Project, which operated a 35-station network of continuously recording, digital, broad-band seismometers over all of Iceland 1996-1998. The structure of the upper mantle was determined using the ACH damped least-squares method and involved 42 stations, 3159 P-wave, and 1338S-wave arrival times, including the phases P, pP, sP, PP, SP, PcP, PKIKP, pPKIKP, S, sS, SS, SKS and Sdiff. Artefacts, both perceptual and parametric, were minimized by well-tested smoothing techniques involving layer thinning and offset-and-averaging. Resolution is good beneath most of Iceland from ~60km depth to a maximum of ~450km depth and beneath the Tjornes Fracture Zone and near-shore parts of the Reykjanes ridge. The results reveal a coherent, negative wave-speed anomaly with a diameter of 200-250km and anomalies in P-wave speed, VP, as strong as -2.7 per cent and in S-wave speed, VS, as strong as -4.9 per cent. The anomaly extends from the surface to the limit of good resolution at ~450km depth. In the upper ~250km it is centred beneath the eastern part of the Middle Volcanic Zone, coincident with the centre of the ~100mGal Bouguer gravity low over Iceland, and a lower crustal low-velocity zone identified by receiver functions. This is probably the true centre of the Iceland hotspot. In the upper ~200km, the low-wave-speed body extends along the Reykjanes ridge but is sharply truncated beneath the Tjornes Fracture Zone. This suggests that material may flow unimpeded along the Reykjanes ridge from beneath Iceland but is blocked beneath the Tjornes Fracture Zone. The magnitudes of the VP, VS and VP/VS anomalies cannot be explained by elevated temperature alone, but favour a model of maximum temperature anomalies <200K, along with up to ~2 per cent of partial melt in the depth range ~100-300km beneath east-central Iceland. The anomalous body is approximately cylindrical in the top 250km but tabular in shape at greater depth, elongated north-south and generally underlying the spreading plate boundary. Such a morphological change and its relationship to surface rift zones are predicted to occur in convective upwellings driven by basal heating, passive upwelling in response to plate separation and lateral temperature gradients. Although we cannot resolve structure deeper than ~450km, and do not detect a bottom to the anomaly, these models suggest that it extends no deeper than the mantle transition zone. Such models thus suggest a shallow origin for the Iceland hotspot rather than a deep mantle plume, and imply that the hotspot has been located on the spreading ridge in the centre of the north Atlantic for its entire history, and is not fixed relative to other Atlantic hotspots. The results are consistent with recent, regional full-thickness mantle tomography and whole-mantle tomography images that show a strong, low-wave-speed anomaly beneath the Iceland region that is confined to the upper mantle and thus do not require a plume in the lower mantle. Seismic and geochemical observations that are interpreted as indicating a lower mantle, or core-mantle boundary origin for the North Atlantic Igneous Province and the Iceland hotspot should be re-examined to consider whether they are consistent with upper mantle processes.

  9. Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle

    USGS Publications Warehouse

    Foulger, G.R.; Pritchard, M.J.; Julian, B.R.; Evans, J.R.; Allen, R.M.; Nolet, G.; Morgan, W.J.; Bergsson, B.H.; Erlendsson, P.; Jakobsdottir, S.; Ragnarsson, S.; Stefansson, R.; Vogfjord, K.

    2001-01-01

    We report the results of the highest-resolution teleseismic tomography study yet performed of the upper mantle beneath Iceland. The experiment used data gathered by the Iceland Hotspot Project, which operated a 35-station network of continuously recording, digital, broad-band seismometers over all of Iceland 1996-1998. The structure of the upper mantle was determined using the ACH damped least-squares method and involved 42 stations, 3159 P-wave, and 1338 S-wave arrival times, including the phases P, pP, sP, PP, SP, PcP, PKIKP, pPKIKP, S, sS, SS, SKS and Sdiff. Artefacts, both perceptual and parametric, were minimized by well-tested smoothing techniques involving layer thinning and offset-and-averaging. Resolution is good beneath most of Iceland from ??? 60 km depth to a maximum of ??? 450 km depth and beneath the Tjornes Fracture Zone and near-shore parts of the Reykjanes ridge. The results reveal a coherent, negative wave-speed anomaly with a diameter of 200-250 km and anomalies in P-wave speed, Vp, as strong as -2.7 per cent and in S-wave speed, Vs, as strong as -4.9 per cent. The anomaly extends from the surface to the limit of good resolution at ??? 450 km depth. In the upper ??? 250 km it is centred beneath the eastern part of the Middle Volcanic Zone, coincident with the centre of the ??? 100 mGal Bouguer gravity low over Iceland, and a lower crustal low-velocity zone identified by receiver functions. This is probably the true centre of the Iceland hotspot. In the upper ??? 200 km, the low-wave-speed body extends along the Reykjanes ridge but is sharply truncated beneath the Tjornes Fracture Zone. This suggests that material may flow unimpeded along the Reykjanes ridge from beneath Iceland but is blocked beneath the Tjornes Fracture Zone. The magnitudes of the Vp, Vs and Vp/Vs anomalies cannot be explained by elevated temperature alone, but favour a model of maximum temperature anomalies <200 K, along with up to ??? 2 per cent of partial melt in the depth range ??? 100-300 km beneath east-central Iceland. The anomalous body is approximately cylindrical in the top 250 km but tabular in shape at greater depth, elongated north-south and generally underlying the spreading plate boundary. Such a morphological change and its relationship to surface rift zones are predicted to occur in convective upwellings driven by basal heating, passive upwelling in response to plate separation and lateral temperature gradients. Although we cannot resolve structure deeper than ??? 450 km, and do not detect a bottom to the anomaly, these models suggest that it extends no deeper than the mantle transition zone. Such models thus suggest a shallow origin for the Iceland hotspot rather than a deep mantle plume, and imply that the hotspot has been located on the spreading ridge in the centre of the north Atlantic for its entire history, and is not fixed relative to other Atlantic hotspots. The results are consistent with recent, regional full-thickness mantle tomography and whole-mantle tomography images that show a strong, low-wave-speed anomaly beneath the Iceland region that is confined to the upper mantle and thus do not require a plume in the lower mantle. Seismic and geochemical observations that are interpreted as indicating a lower mantle, or core-mantle boundary origin for the North Atlantic Igneous Province and the Iceland hotspot should be re-examined to consider whether they are consistent with upper mantle processes.

  10. [A Patient with Early-Stage Multiple System Atrophy Showing Augmented Nystagmus in Light].

    PubMed

    Oguri, Masayoshi; Nakamura, Yousuke; Hara, Ayako; Kitano, Hiroya; Motokura, Toru

    2015-04-01

    The ability to fix the eyes on a target, visual fixation, is important for the maintenance of equilibrium. The visual suppression (VS) test is one method of measuring the function of visual fixation. The test records caloric nystagmus by electrooculography, and the maximum slow phase velocity of caloric nystagmus in darkness is compared with the slow phase velocity in light with eyes fixed. Lesions of the cerebellum, brain stem, and cerebrum cause abnormalities of VS. We report a patient whose VS became a clue in the diagnosis of a disorder of the central nervous system. A 54-year-old man complained of dizziness, which gradually increased in frequency over 5 months. He visited several clinics, where vestibular neutritis and cervical spondylosis were suspected and treated without improvement. Although a pure-tone auditory test revealed bilateral normal hearing, a caloric test showed a weak response and VS was lost with augmentation of caloric nystagmus in light on both sides. Both eye tracking and optokinetic nystagmus tests were abnormal. Although magnetic resonance imaging showed no abnormalities, single photon emission computed tomography revealed decreased blood flow in the parietal area. VS of caloric nystagmus towards the side of a lesion is reduced or abolished after unilateral flocculus damage, and is abolished bilaterally after bilateral flocculus damage. In the case of a parietal lobe or pontine lesion, VS is strongly abolished, and even augmentation of caloric nystagmus may be observed. In the present case, the patient was diagnosed with multiple-system atrophy after onset of dizziness. PMID:26536776

  11. Singular value decomposition metrics show limitations of detector design in diffuse fluorescence tomography

    PubMed Central

    Leblond, Frederic; Tichauer, Kenneth M.; Pogue, Brian W.

    2010-01-01

    The spatial resolution and recovered contrast of images reconstructed from diffuse fluorescence tomography data are limited by the high scattering properties of light propagation in biological tissue. As a result, the image reconstruction process can be exceedingly vulnerable to inaccurate prior knowledge of tissue optical properties and stochastic noise. In light of these limitations, the optimal source-detector geometry for a fluorescence tomography system is non-trivial, requiring analytical methods to guide design. Analysis of the singular value decomposition of the matrix to be inverted for image reconstruction is one potential approach, providing key quantitative metrics, such as singular image mode spatial resolution and singular data mode frequency as a function of singular mode. In the present study, these metrics are used to analyze the effects of different sources of noise and model errors as related to image quality in the form of spatial resolution and contrast recovery. The image quality is demonstrated to be inherently noise-limited even when detection geometries were increased in complexity to allow maximal tissue sampling, suggesting that detection noise characteristics outweigh detection geometry for achieving optimal reconstructions. PMID:21258566

  12. Feature-space assessment of electrical impedance tomography coregistered with computed tomography in detecting multiple contrast targets

    SciTech Connect

    Krishnan, Kalpagam; Liu, Jeff; Kohli, Kirpal

    2014-06-15

    Purpose: Fusion of electrical impedance tomography (EIT) with computed tomography (CT) can be useful as a clinical tool for providing additional physiological information about tissues, but requires suitable fusion algorithms and validation procedures. This work explores the feasibility of fusing EIT and CT images using an algorithm for coregistration. The imaging performance is validated through feature space assessment on phantom contrast targets. Methods: EIT data were acquired by scanning a phantom using a circuit, configured for injecting current through 16 electrodes, placed around the phantom. A conductivity image of the phantom was obtained from the data using electrical impedance and diffuse optical tomography reconstruction software (EIDORS). A CT image of the phantom was also acquired. The EIT and CT images were fused using a region of interest (ROI) coregistration fusion algorithm. Phantom imaging experiments were carried out on objects of different contrasts, sizes, and positions. The conductive medium of the phantoms was made of a tissue-mimicking bolus material that is routinely used in clinical radiation therapy settings. To validate the imaging performance in detecting different contrasts, the ROI of the phantom was filled with distilled water and normal saline. Spatially separated cylindrical objects of different sizes were used for validating the imaging performance in multiple target detection. Analyses of the CT, EIT and the EIT/CT phantom images were carried out based on the variations of contrast, correlation, energy, and homogeneity, using a gray level co-occurrence matrix (GLCM). A reference image of the phantom was simulated using EIDORS, and the performances of the CT and EIT imaging systems were evaluated and compared against the performance of the EIT/CT system using various feature metrics, detectability, and structural similarity index measures. Results: In detecting distilled and normal saline water in bolus medium, EIT as a stand-alone imaging system showed contrast discrimination of 47%, while the CT imaging system showed a discrimination of only 1.5%. The structural similarity index measure showed a drop of 24% with EIT imaging compared to CT imaging. The average detectability measure for CT imaging was found to be 2.375 ± 0.19 before fusion. After complementing with EIT information, the detectability measure increased to 11.06 ± 2.04. Based on the feature metrics, the functional imaging quality of CT and EIT were found to be 2.29% and 86%, respectively, before fusion. Structural imaging quality was found to be 66% for CT and 16% for EIT. After fusion, functional imaging quality improved in CT imaging from 2.29% to 42% and the structural imaging quality of EIT imaging changed from 16% to 66%. The improvement in image quality was also observed in detecting objects of different sizes. Conclusions: The authors found a significant improvement in the contrast detectability performance of CT imaging when complemented with functional imaging information from EIT. Along with the feature assessment metrics, the concept of complementing CT with EIT imaging can lead to an EIT/CT imaging modality which might fully utilize the functional imaging abilities of EIT imaging, thereby enhancing the quality of care in the areas of cancer diagnosis and radiotherapy treatment planning.

  13. Using cone beam computed tomography images to diagnose multiple taurodontisms.

    PubMed

    Borges, Alvaro Henrique; Mamede-Neto, Iussif; Volpato, Luiz Evaristo Ricci; Pedro, Fabio Luis Miranda; Bueno, Mike Reis; Estrela, Carlos

    2014-01-01

    Taurodontism is a developmental anomaly that manifests as an alteration in a patient's internal morphology and is characterized by the lack of constriction at the level of the cementoenamel junction, which results in an apical extension of the pulp chamber that extends into the root area of a multiradicular tooth. This report presents a case of an otherwise healthy patient with 12 hypertaurodontic teeth, which were detected by using cone beam computed tomography (CBCT). It is essential to emphasize the importance of routine imaging examinations for diagnosing developmental dental anomalies such as taurodontism, as this condition is generally not found by routine oral examination, and is not necessarily restricted to syndromic patients. CBCT images contribute to the diagnosis of and treatment plan for taurodontism. PMID:24598505

  14. Multiple pulmonary sclerosing hemangiomas (pneumocytoma) mimicking lung metastasis detected in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Rajan, Firoz; Mehta, Sangita; Mohanan, Vyshakh; Shinto, Ajit Sugunan

    2014-07-01

    Pulmonary sclerosing hemangioma (PSH), or the alternative name of "sclerosing pneumocytoma," is a rare benign neoplasm. PSH is often asymptomatic and presents as a solitary or multiple pulmonary nodules on radiologic imaging studies. Few articles have been reported to describe the fluorodeoxyglucose positron emission tomography (FDG PET) findings about PSH. The authors describe an interesting but uncommonly encountered cause of false positive FDG PET scan in the thorax in a 25-year-old woman, a known case of arteriovenous malformation of oral cavity who underwent embolization and presented with incidental detection of bilateral lung nodules. She is asymptomatic and is on follow-up. PMID:25210285

  15. Multiple pulmonary sclerosing hemangiomas (pneumocytoma) mimicking lung metastasis detected in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Rajan, Firoz; Mehta, Sangita; Mohanan, Vyshakh; Shinto, Ajit Sugunan

    2014-01-01

    Pulmonary sclerosing hemangioma (PSH), or the alternative name of “sclerosing pneumocytoma,” is a rare benign neoplasm. PSH is often asymptomatic and presents as a solitary or multiple pulmonary nodules on radiologic imaging studies. Few articles have been reported to describe the fluorodeoxyglucose positron emission tomography (FDG PET) findings about PSH. The authors describe an interesting but uncommonly encountered cause of false positive FDG PET scan in the thorax in a 25-year-old woman, a known case of arteriovenous malformation of oral cavity who underwent embolization and presented with incidental detection of bilateral lung nodules. She is asymptomatic and is on follow-up. PMID:25210285

  16. Multiple-energy Techniques in Industrial Computerized Tomography

    DOE R&D Accomplishments Database

    Schneberk, D.; Martz, H.; Azevedo, S.

    1990-08-01

    Considerable effort is being applied to develop multiple-energy industrial CT techniques for materials characterization. Multiple-energy CT can provide reliable estimates of effective Z (Z{sub eff}), weight fraction, and rigorous calculations of absolute density, all at the spatial resolution of the scanner. Currently, a wide variety of techniques exist for CT scanners, but each has certain problems and limitations. Ultimately, the best multi-energy CT technique would combine the qualities of accuracy, reliability, and wide range of application, and would require the smallest number of additional measurements. We have developed techniques for calculating material properties of industrial objects that differ somewhat from currently used methods. In this paper, we present our methods for calculating Z{sub eff}, weight fraction, and density. We begin with the simplest case -- methods for multiple-energy CT using isotopic sources -- and proceed to multiple-energy work with x-ray machine sources. The methods discussed here are illustrated on CT scans of PBX-9502 high explosives, a lexan-aluminum phantom, and a cylinder of glass beads used in a preliminary study to determine if CT can resolve three phases: air, water, and a high-Z oil. In the CT project at LLNL, we have constructed several CT scanners of varying scanning geometries using {gamma}- and x-ray sources. In our research, we employed two of these scanners: pencil-beam CAT for CT data using isotopic sources and video-CAT equipped with an IRT micro-focal x-ray machine source.

  17. Positron emission tomography-computed tomography in the diagnostic evaluation of smoldering multiple myeloma: identification of patients needing therapy

    PubMed Central

    Siontis, B; Kumar, S; Dispenzieri, A; Drake, M T; Lacy, M Q; Buadi, F; Dingli, D; Kapoor, P; Gonsalves, W; Gertz, M A; Rajkumar, S V

    2015-01-01

    We studied 188 patients with a suspected smoldering multiple myeloma (MM) who had undergone a positron emission tomography-computed tomography (PET-CT) scan as part of their clinical evaluation. PET-CT was positive (clinical radiologist interpretation of increased bone uptake and/or evidence of lytic bone destruction) in 74 patients and negative in 114 patients. Of these, 25 patients with a positive PET-CT and 97 patients with a negative PET-CT were observed without therapy and formed the study cohort (n=122). The probability of progression to MM within 2 years was 75% in patients with a positive PET-CT observed without therapy compared with 30% in patients with a negative PET-CT; median time to progression was 21 months versus 60 months, respectively, P=0.0008. Of 25 patients with a positive PET-CT, the probability of progression was 87% at 2 years in those with evidence of underlying osteolysis (n=16) and 61% in patients with abnormal PET-CT uptake but no evidence of osteolysis (n=9). Patients with positive PET-CT and evidence of underlying osteolysis have a high risk of progression to MM within 2 years when observed without therapy. These observations support recent changes to imaging requirements in the International Myeloma Working Group updated diagnostic criteria for MM. PMID:26495861

  18. Positron emission tomography-computed tomography in the diagnostic evaluation of smoldering multiple myeloma: identification of patients needing therapy.

    PubMed

    Siontis, B; Kumar, S; Dispenzieri, A; Drake, M T; Lacy, M Q; Buadi, F; Dingli, D; Kapoor, P; Gonsalves, W; Gertz, M A; Rajkumar, S V

    2015-01-01

    We studied 188 patients with a suspected smoldering multiple myeloma (MM) who had undergone a positron emission tomography-computed tomography (PET-CT) scan as part of their clinical evaluation. PET-CT was positive (clinical radiologist interpretation of increased bone uptake and/or evidence of lytic bone destruction) in 74 patients and negative in 114 patients. Of these, 25 patients with a positive PET-CT and 97 patients with a negative PET-CT were observed without therapy and formed the study cohort (n=122). The probability of progression to MM within 2 years was 75% in patients with a positive PET-CT observed without therapy compared with 30% in patients with a negative PET-CT; median time to progression was 21 months versus 60 months, respectively, P=0.0008. Of 25 patients with a positive PET-CT, the probability of progression was 87% at 2 years in those with evidence of underlying osteolysis (n=16) and 61% in patients with abnormal PET-CT uptake but no evidence of osteolysis (n=9). Patients with positive PET-CT and evidence of underlying osteolysis have a high risk of progression to MM within 2 years when observed without therapy. These observations support recent changes to imaging requirements in the International Myeloma Working Group updated diagnostic criteria for MM. PMID:26495861

  19. Multiple sclerosis patients show sexual dimorphism in cytokine responses to myelin antigens

    PubMed Central

    Moldovan, Ioana R.; Cotleur, Anne C.; Zamor, Natacha; Butler, Robert S.; Pelfrey, Clara M.

    2008-01-01

    Multiple sclerosis affects more women than men. The reasons for this are unknown. Previously, we have shown significant differences in women versus men in inflammatory cytokine responses to the major protein component of myelin, proteolipid protein (PLP), which is thought to be a target in MS patients. Here, using the ELISPOT assay, we examined sex differences in single-cell secretion of Th1 and Th2 cytokines from freshly isolated PBMC between relapsing remitting (RR) MS patients and healthy individuals. Cells were stimulated with MS-associated antigens including proteolipid protein (PLP), myelin basic protein (MBP), myelin oligodendrocyte glycoprotein (MOG), and non-disease related antigens. Our data show a sex bias in the cytokine responses to multiple MS-relevant myelin antigens: Women with MS show IFNγ-skewed responses and men with MS show IL-5-skewed responses. These data extend our previous findings (Pelfrey et al., 2002): (1) by demonstrating gender skewing in cytokine responses to an expanded myelin antigen repertoire, which includes MBP, MOG and PLP; (2) by showing TNFα and IL-10 do not display comparable gender skewing compared to IFNγ and IL5; (3) by defining the patient population as early, untreated RR MS patients to avoid confounding factors, such as different disease stages/disability and immunomodulatory therapy; and (4) by showing HLA type does not appear to underlie the gender differences. These findings may explain increased susceptibility to MS in women and could contribute to the differences in disease severity between men and women. PMID:18022700

  20. Limited-projection-angle hybrid fluorescence molecular tomography of multiple molecules.

    PubMed

    Radrich, Karin; Mohajerani, Pouyan; Bussemer, Johanna; Schwaiger, Markus; Beer, Ambros J; Ntziachristos, Vasilis

    2014-04-01

    An advantage of fluorescence methods over other imaging modalities is the ability to concurrently resolve multiple moieties using fluorochromes emitting at different spectral regions. Simultaneous imaging of spectrally separated agents is helpful in interrogating multiple functions or establishing internal controls for accurate measurements. Herein, we investigated multimoiety imaging in the context of a limited-projection-angle hybrid fluorescence molecular tomography (FMT), and x-ray computed tomography implementation and the further registration with positron emission tomography (PET) data. Multichannel FMT systems may image fluorescent probes of varying distribution patterns. Therefore, it is possible that different channels may require different use of priors and regularization parameters. We examined the performance of automatically estimating regularization factors implementing priors, using data-driven regularization specific for limited-projection-angle schemes. We were particularly interested in identifying the implementation variations between hybrid-FMT channels due to probe distribution variation. For this reason, initial validation of the data-driven algorithm on a phantom was followed by imaging different agent distributions in animals, assuming superficial and deep seated activity. We further demonstrate the benefits of combining hybrid FMT with PET to gain multiple readings on the molecular composition of disease. PMID:24770661

  1. Neuromyelitis optica and multiple sclerosis: Seeing differences through optical coherence tomography.

    PubMed

    Bennett, J L; de Seze, J; Lana-Peixoto, M; Palace, J; Waldman, A; Schippling, S; Tenembaum, S; Banwell, B; Greenberg, B; Levy, M; Fujihara, K; Chan, K H; Kim, H J; Asgari, N; Sato, D K; Saiz, A; Wuerfel, J; Zimmermann, H; Green, A; Villoslada, P; Paul, F

    2015-05-01

    Neuromyelitis optica (NMO) is an inflammatory autoimmune disease of the central nervous system that preferentially targets the optic nerves and spinal cord. The clinical presentation may suggest multiple sclerosis (MS), but a highly specific serum autoantibody against the astrocytic water channel aquaporin-4 present in up to 80% of NMO patients enables distinction from MS. Optic neuritis may occur in either condition resulting in neuro-anatomical retinal changes. Optical coherence tomography (OCT) has become a useful tool for analyzing retinal damage both in MS and NMO. Numerous studies showed that optic neuritis in NMO typically results in more severe retinal nerve fiber layer (RNFL) and ganglion cell layer thinning and more frequent development of microcystic macular edema than in MS. Furthermore, while patients' RNFL thinning also occurs in the absence of optic neuritis in MS, subclinical damage seems to be rare in NMO. Thus, OCT might be useful in differentiating NMO from MS and serve as an outcome parameter in clinical studies. PMID:25662342

  2. Neuromyelitis optica and multiple sclerosis: Seeing differences through optical coherence tomography

    PubMed Central

    Bennett, JL; de Seze, J; Lana-Peixoto, M; Palace, J; Waldman, A; Schippling, S; Tenembaum, S; Banwell, B; Greenberg, B; Levy, M; Fujihara, K; Chan, KH; Kim, HJ; Asgari, N; Sato, DK; Saiz, A; Wuerfel, J; Zimmermann, H; Green, A; Villoslada, P

    2015-01-01

    Neuromyelitis optica (NMO) is an inflammatory autoimmune disease of the central nervous system that preferentially targets the optic nerves and spinal cord. The clinical presentation may suggest multiple sclerosis (MS), but a highly specific serum autoantibody against the astrocytic water channel aquaporin-4 present in up to 80% of NMO patients enables distinction from MS. Optic neuritis may occur in either condition resulting in neuro-anatomical retinal changes. Optical coherence tomography (OCT) has become a useful tool for analyzing retinal damage both in MS and NMO. Numerous studies showed that optic neuritis in NMO typically results in more severe retinal nerve fiber layer (RNFL) and ganglion cell layer thinning and more frequent development of microcystic macular edema than in MS. Furthermore, while patients RNFL thinning also occurs in the absence of optic neuritis in MS, subclinical damage seems to be rare in NMO. Thus, OCT might be useful in differentiating NMO from MS and serve as an outcome parameter in clinical studies. PMID:25662342

  3. Uncovered: Progenitors of globular clusters showing off their multiple stellar populations

    NASA Astrophysics Data System (ADS)

    de Grijs, Richard; Li, Chengyuan; Deng, Licai; Geller, Aaron M.; Xin, Yu; Hu, Yi; Faucher-Giguere, Claude-Andre

    2016-01-01

    Stars in star clusters are thought to form in a single burst from a common progenitor cloud of molecular gas, resulting in so-called simple stellar populations. However, old, massive globular clusters—with ages greater than 10 billion years—often host multiple stellar populations, indicating that more than one star-forming event may have occurred during their lifetimes. The most popular scenario for their formation invokes colliding stellar winds from late-stage, asymptotic-giant-branch stars. If this were correct, the initial globular cluster masses should be at least 10 times more massive than their current masses of typically a few x 105 Msun. However, large populations of clusters with masses greater than a few x 106 Msun are not found in the local Universe. Here we present Hubble Space Telescope observations of three 1-2 billion-year-old, massive star clusters in the Magellanic Clouds which show unequivocal evidence of burst-like star-formation activity that occurred a few x 108 years after their initial formation era. The spatial distributions of the younger stellar generations suggest that they may have originated from ambient gas clouds accreted by the clusters while orbiting in the disks of their host galaxies rather than from colliding stellar winds. Simple models imply that such clusters could indeed accrete sufficient gas reservoirs to form these stars. This may eventually give rise to the appearance of multiple stellar populations in globular clusters.

  4. Multiple idiopathic external and internal resorption: Case report with cone-beam computed tomography findings

    PubMed Central

    Uzuntas, Ceren Feriha; Kurt, Hakan

    2014-01-01

    Root resorption is loss of dental hard tissue as a result of clastic activities. The dental hard tissue of permanent teeth does not normally undergo resorption, except in cases of inflammation or trauma. However, there are rare cases of tooth resorption of an unknown cause, known as "idiopathic root resorption." This report would discuss a rare case of multiple idiopathic resorption in the permanent maxillary and mandibular teeth of an otherwise healthy 36-year-old male patient. In addition to a clinical examination, the patient was imaged using conventional radiography and cone-beam computed tomography (CBCT). The examinations revealed multiple external and internal resorption of the teeth in all four quadrants of the jaws with an unknown cause. Multiple root resorption is a rare clinical phenomenon that should be examined using different radiographic modalities. Cross-sectional CBCT is useful in the diagnosis and examination of such lesions. PMID:25473640

  5. Pituitary abscess showing high uptake of thallium-201 on single photon emission computed tomography--case report.

    PubMed

    Shimamura, Norihito; Ogane, Kazumi; Takahashi, Toshio; Tabata, Hidefumi; Ohkuma, Hiroki; Suzuki, Shigeharu

    2003-02-01

    A 32-year-old female presented with a rare case of pituitary abscess manifesting as homonymous hemianopsia. Serum prolactin level was slightly high (40.8 ng/ml). Magnetic resonance (MR) imaging showed the content of the lesion as homogeneously isointense on the T1-weighted images and hyperintense on the T2-weighted images. The capsule of the lesion, which appeared thin and smooth, was enhanced by gadolinium. Dural enhancement around the sella turcica was also recognized. Thallium-201 single photon emission computed tomography (201Tl SPECT) showed homogeneous high accumulation in the pituitary region on both the early and delayed images. The lesion was treated via a transnasaltranssphenoidal approach. The cystic lesion contained pus and the capsule consisted of normal pituitary gland with inflammatory changes. The patient was treated with antibiotics for 3 weeks and the pituitary abscess was cured completely. Pituitary abscess can be differentiated from pituitary adenoma as lesion with a homogeneous high uptake on 201Tl SPECT on both the early and delayed images, and no enhancement of the central portion on MR images. PMID:12627890

  6. Multiple-frequency tomography of the upper mantle beneath the African/Iberian collision zone

    NASA Astrophysics Data System (ADS)

    Bonnin, Mickal; Nolet, Guust; Villaseor, Antonio; Gallart, Josep; Thomas, Christine

    2014-09-01

    During the Cenozoic, the geodynamics of the western Mediterranean domain has been characterized by a complex history of subduction of Mesozoic oceanic lithosphere. The final stage of these processes is proposed to have led to the development of the Calabria and Gibraltar arcs, whose formation is still under debate. In this study, we take advantage of the dense broad-band station networks now available in the Alborn Sea region, to develop a high-resolution 3-D tomographic P velocity model of the upper mantle beneath the African/Iberian collision zone that will better constraint the past dynamics of this zone. The model is based on 13200 teleseismic arrival times recorded between 2008 and 2012 at 279 stations for which cross-correlation delays are measured with a new technique in different frequency bands centred between 0.03 and 1.0 Hz, and for the first time interpreted using multiple frequency tomography. Our model shows, beneath the Alborn Sea, a strong (4 per cent) fast vertically dipping anomaly observed to at least 650 km depth. The arched shape of this anomaly, and its extent at depth, are coherent with a lithospheric slab, thus favouring the hypothesis of a westward consumption of the Ligurian ocean slab by roll-back during Cenozoic. In addition to this fast anomaly in the deep upper mantle, high intensity slow anomalies are widespread in the lithosphere and asthenosphere beneath Morocco and southern Spain. These anomalies are correlated at the surface with the position of the Rif and Atlas orogens and with Cenozoic volcanic fields. We thus confirm the presence, beneath Morocco, of an anomalous (hot?) upper mantle, but without clear indication for a lateral spreading of the Canary plume to the east.

  7. Fluorescence molecular tomography on animal model by means of multiple views structured light illumination

    NASA Astrophysics Data System (ADS)

    Ducros, N.; Bassi, A.; Valentini, G.; Canti, G.; Arridge, S.; D'Andrea, C.

    2013-03-01

    Fluorescence molecular tomography (FMT) is quite demanding in terms of acquisition/computational times due to the huge amount of data. Different research groups have proposed compression approaches regarding both illumination (wide field structured light instead of raster point scanning) and detection (compression of the acquired images). The authors have previously proposed a fast FMT reconstruction method based on the combination of a multiple-view approach with a full compression scheme. This method had been successfully tested on a cylindrical phantom and is being generalized in this paper to samples of arbitrary shape. The devised procedure and algorithms have been tested on an ex-vivo mouse.

  8. Genome-wide association study of blood lead shows multiple associations near ALAD.

    PubMed

    Warrington, Nicole M; Zhu, Gu; Dy, Veronica; Heath, Andrew C; Madden, Pamela A F; Hemani, Gibran; Kemp, John P; Mcmahon, George; St Pourcain, Beate; Timpson, Nicholas J; Taylor, Caroline M; Golding, Jean; Lawlor, Debbie A; Steer, Colin; Montgomery, Grant W; Martin, Nicholas G; Davey Smith, George; Evans, David M; Whitfield, John B

    2015-07-01

    Exposure to high levels of environmental lead, or biomarker evidence of high body lead content, is associated with anaemia, developmental and neurological deficits in children, and increased mortality in adults. Adverse effects of lead still occur despite substantial reduction in environmental exposure. There is genetic variation between individuals in blood lead concentration but the polymorphisms contributing to this have not been defined. We measured blood or erythrocyte lead content, and carried out genome-wide association analysis, on population-based cohorts of adult volunteers from Australia and UK (N = 5433). Samples from Australia were collected in two studies, in 1993-1996 and 2002-2005 and from UK in 1991-1992. One locus, at ALAD on chromosome 9, showed consistent association with blood lead across countries and evidence for multiple independent allelic effects. The most significant single nucleotide polymorphism (SNP), rs1805313 (P = 3.91 10(-14) for lead concentration in a meta-analysis of all data), is known to have effects on ALAD expression in blood cells but other SNPs affecting ALAD expression did not affect blood lead. Variants at 12 other loci, including ABO, showed suggestive associations (5 10(-6) > P > 5 10(-8)). Identification of genetic polymorphisms affecting blood lead reinforces the view that genetic factors, as well as environmental ones, are important in determining blood lead levels. The ways in which ALAD variation affects lead uptake or distribution are still to be determined. PMID:25820613

  9. Cytokine profiles show heterogeneity of interferon-β response in multiple sclerosis patients

    PubMed Central

    Hegen, Harald; Adrianto, Indra; Lessard, Christopher J.; Millonig, Alban; Bertolotto, Antonio; Comabella, Manuel; Giovannoni, Gavin; Guger, Michael; Hoelzl, Martina; Khalil, Michael; Fazekas, Franz; Killestein, Joep; Lindberg, Raija L.P.; Malucchi, Simona; Mehling, Matthias; Montalban, Xavier; Rudzki, Dagmar; Schautzer, Franz; Sellebjerg, Finn; Sorensen, Per Soelberg; Deisenhammer, Florian; Steinman, Lawrence

    2016-01-01

    Objective: To evaluate serum cytokine profiles for their utility to determine the heterogeneous responses to interferon (IFN)–β treatment in patients with multiple sclerosis (MS). Methods: Patients with relapsing-remitting MS (RRMS) or clinically isolated syndrome receiving de novo IFN-β treatment were included in this prospective, observational study. Number of relapses and changes in disability were assessed 2 years prior to and 2 years after initiation of treatment. Sera were collected at baseline and after 3 months on therapy. Cytokine levels in sera were assessed by Luminex multiplex assays. Baseline cytokine profiles were grouped by hierarchical clustering analysis. Demographic features, changes in cytokines, and clinical outcome were then assessed in the clustered patient groups. Results: A total of 157 patients were included in the study and clustered into 6 distinct subsets by baseline cytokine profiles. These subsets differed significantly in their clinical and biological response to IFN-β therapy. Two subsets were associated with patients who responded poorly to therapy. Two other subsets, associated with a good response to therapy, showed a significant reduction in relapse rates and no worsening of disability. Each subset also had differential changes in cytokine levels after 3 months of IFN-β treatment. Conclusions: There is heterogeneity in the immunologic pathways of the RRMS population, which correlates with IFN-β response. PMID:26894205

  10. Imaging of neuroinflammation in Alzheimer's disease, multiple sclerosis and stroke: Recent developments in positron emission tomography.

    PubMed

    Janssen, Bieneke; Vugts, Danielle J; Funke, Uta; Molenaar, Ger T; Kruijer, Perry S; van Berckel, Bart N M; Lammertsma, Adriaan A; Windhorst, Albert D

    2016-03-01

    Neuroinflammation is thought to play a pivotal role in many diseases affecting the brain, including Alzheimer's disease, multiple sclerosis and stroke. Neuroinflammation is characterised predominantly by microglial activation, which can be visualised using positron emission tomography (PET). Traditionally, translocator protein 18kDa (TSPO) is the target for imaging of neuroinflammation using PET. In this review, recent preclinical and clinical research using PET in Alzheimer's disease, multiple sclerosis and stroke is summarised. In addition, new molecular targets for imaging of neuroinflammation, such as monoamine oxidases, adenosine receptors and cannabinoid receptor type 2, are discussed. This article is part of a Special Issue entitled: Neuro Inflammation edited by Helga E. de Vries and Markus Schwaninger. PMID:26643549

  11. Signal simulation and signal processing for multiple reference optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Neuhaus, Kai; Subhash, Hrebesh; Dsouza, Roshan; Hogan, Josh; Wilson, Carol; Leahy, Martin

    2015-03-01

    The generation of a synthetic MR-OCT signal is presented and compared to a real acquired signal. Multiple reference optical coherence tomography (MR-OCT) is a novel time-domain interferometric system. The MR-OCT principle is adding a partial mirror to extend the axial scan range, which effectively extends the scan depth for imaging. The actuation of the scan mirror required for time-domain OCT, was demonstrated to operate with a low cost miniature voice coil, such as a speaker extracted from a smartphone or CD/DVD pick-up system. Building a compact and cost-effective optical imaging system will enable affordable medical diagnosis at low-resource setting applications. The partial mirror recirculates multiple reflections (orders) into the interferometric system and the increase of optical path delay does increase the beat frequency of the interference signal. The synthesis of such an interference signal using a numerical method is described in this manuscript.

  12. Case report: gallium study showing a rare form of multiple myeloma

    SciTech Connect

    Meyers, E.; Kasner, J.R.

    1981-12-01

    A case study is presented in which a rare form of multiple myeloma with soft tissue involvememt was diagnosed by a gallium scan using 3 mCi of Ga-67 citrate. Subsequent resting cardiac blood pool images suggested pericardial rather than myocardial involvement. (JMT)

  13. The role of positron emission tomography with 18F-fluorodeoxyglucose integrated with computed tomography in the evaluation of patients with multiple myeloma undergoing allogeneic stem cell transplantation.

    PubMed

    Patriarca, Francesca; Carobolante, Francesca; Zamagni, Elena; Montefusco, Vittorio; Bruno, Benedetto; Englaro, Emanuaela; Nanni, Cristina; Geatti, Onelio; Isola, Miriam; Sperotto, Alessandra; Buttignol, Silvia; Stocchi, Raffaella; Corradini, Paolo; Cavo, Michele; Fanin, Renato

    2015-06-01

    Positron emission tomography (PET) integrated with computed tomography (PET/CT) has been reported to be useful for screening myelomatous lesions at diagnosis in patients with multiple myeloma (MM) and for monitoring response to autologous stem cell transplantation (auto-SCT). The aim of the study was to evaluate the prognostic significance of PET/CT in MM patients who received allogeneic stem cell transplantation (allo-SCT). Patients who underwent upfront auto-SCT followed by allo-SCT, either as consolidation or salvage treatment, were studied with PET/CT before and/or within 6 months after allo-SCT. The number, the maximum standard uptake value (SUV), and the location (medullary or extramedullary) of focal lesions (FLs) were recorded and investigated as predictors of progression-free survival (PFS) and overall survival (OS) by univariate and multivariate analyses. Fifty-four patients had a PET/CT scan before allo-SCT. Of these, 22 patients (41%) had a negative PET/CT scan, 11 patients (20%) showed 1 to 3 FLs, and 21 patients (39%) had either a diffuse bone marrow involvement or more than 3 FLs. SUV was >4.2 in 21 patients (39%) and extramedullary disease (EMD) was present in 6 patients (11%). Multivariate analysis of prognostic factors before allo-SCT showed that persistence of EMD at transplantation was an independent predictor of poor PFS, whereas OS was negatively influenced by unrelated donor and SUV > 4.2. Fifty-nine patients had a PET/CT scan within 6 months after allo-SCT. Multivariate analysis of post-treatment variables showed that persistence of EMD and failure to obtain complete response or very good partial response after allo-SCT were strongly associated with shorter PFS and OS. Of the 46 patients with evaluable PET/CT scans both before and 6 months after allo-SCT, the 23 patients who maintained or reached a PET complete remission showed a significantly prolonged PFS and OS compared with the 23 patients with persistence of any PET positivity (2-year PFS: 51% versus 25%, P= .03; 2-year OS: 81% versus 47%, P= .001). This study indicates that PET/CT imaging before and after allo-SCT is significantly associated with the outcome, suggesting the utility of this technique for MM staging before allo-SCT and for response monitoring after the transplantation. PMID:25754658

  14. Non-osseous uptake on Tc99m methylene diphosphonate in multiple muscles confirmed on SPECT/computed tomography.

    PubMed

    Tarsarya, Sunita; Marwah, Atul; Shah, Hardik; Jaiswar, Rajnath

    2012-07-01

    A 55-year-old female presented with complaints of pain in the left hip radiating to the left lower limb since 1 year. Computed tomography (CT) abdomen and pelvis revealed bony destruction of pubic symphysis with associated soft tissue component suspicious of infective or metastatic etiology. Magnetic resonance imaging Lumbo-sacral spine performed later revealed altered bone marrow signal in sacral 1-3 vertebrae. Wholebody bone scan with 25 mCi of Tc-99m methylene diphosphonate (MDP) was performed, which revealed multiple skeletal metastases and extraosseous soft tissue uptake was seen involving multiple muscles. We performed single photon emission tomography single photon emission computed tomography (SPECT)/computed tomography (CT) images to precisely delineate the muscle involved and noted calcification on CT images in one of the muscle at site of Tc-99m MDP uptake, no definite calcification was noted in the other muscles. Thus, the final diagnosis was multiple skeletal metastasis with metastatic calcification in multiple muscle from an unknown primary. PMID:23919081

  15. Patient No-Show Predictive Model Development using Multiple Data Sources for an Effective Overbooking Approach

    PubMed Central

    Hanauer, D.A.

    2014-01-01

    Summary Background Patient no-shows in outpatient delivery systems remain problematic. The negative impacts include underutilized medical resources, increased healthcare costs, decreased access to care, and reduced clinic efficiency and provider productivity. Objective To develop an evidence-based predictive model for patient no-shows, and thus improve overbooking approaches in outpatient settings to reduce the negative impact of no-shows. Methods Ten years of retrospective data were extracted from a scheduling system and an electronic health record system from a single general pediatrics clinic, consisting of 7,988 distinct patients and 104,799 visits along with variables regarding appointment characteristics, patient demographics, and insurance information. Descriptive statistics were used to explore the impact of variables on show or no-show status. Logistic regression was used to develop a no-show predictive model, which was then used to construct an algorithm to determine the no-show threshold that calculates a predicted show/no-show status. This approach aims to overbook an appointment where a scheduled patient is predicted to be a no-show. The approach was compared with two commonly-used overbooking approaches to demonstrate the effectiveness in terms of patient wait time, physician idle time, overtime and total cost. Results From the training dataset, the optimal error rate is 10.6% with a no-show threshold being 0.74. This threshold successfully predicts the validation dataset with an error rate of 13.9%. The proposed overbooking approach demonstrated a significant reduction of at least 6% on patient waiting, 27% on overtime, and 3% on total costs compared to other common flat-overbooking methods. Conclusions This paper demonstrates an alternative way to accommodate overbooking, accounting for the prediction of an individual patients show/no-show status. The predictive no-show model leads to a dynamic overbooking policy that could improve patient waiting, overtime, and total costs in a clinic day while maintaining a full scheduling capacity. PMID:25298821

  16. Visual modeling shows that avian host parents use multiple visual cues in rejecting parasitic eggs

    PubMed Central

    Spottiswoode, Claire N.; Stevens, Martin

    2010-01-01

    One of the most striking outcomes of coevolution between species is egg mimicry by brood parasitic birds, resulting from rejection behavior by discriminating host parents. Yet, how exactly does a host detect a parasitic egg? Brood parasitism and egg rejection behavior provide a model system for exploring the relative importance of different visual cues used in a behavioral task. Although hosts are discriminating, we do not know exactly what cues they use, and to answer this it is crucial to account for the receiver's visual perception. Color, luminance (“perceived lightness”) and pattern information have never been simultaneously quantified and experimentally tested through a bird's eye. The cuckoo finch Anomalospiza imberbis and its hosts show spectacular polymorphisms in egg appearance, providing a good opportunity for investigating visual discrimination owing to the large range of patterns and colors involved. Here we combine field experiments in Africa with modeling of avian color vision and pattern discrimination to identify the specific visual cues used by hosts in making rejection decisions. We found that disparity between host and foreign eggs in both color and several aspects of pattern (dispersion, principal marking size, and variability in marking size) were important predictors of rejection, especially color. These cues correspond exactly to the principal differences between host and parasitic eggs, showing that hosts use the most reliable available cues in making rejection decisions, and select for parasitic eggs that are increasingly mimetic in a range of visual attributes. PMID:20421497

  17. Simultaneous multiple-depths en-face optical coherence tomography using multiple signal excitation of acousto-optic deflectors.

    PubMed

    Zurauskas, Mantas; Rogers, John; Podoleanu, Adrian Gh

    2013-01-28

    We present a novel low-coherence interferometer configuration, equipped with acousto-optic deflectors that can be used to simultaneously acquire up to eight time domain optical coherence tomography en-face images. The capabilities of the configuration are evaluated in terms of depth resolution, signal to noise ratio and crosstalk. Then the configuration is employed to demonstrate simultaneous en-face optical coherence tomography imaging at five different depths in a specimen of armadillidium vulgare. PMID:23389175

  18. Multiple Regression Methods Show Great Potential for Rare Variant Association Tests

    PubMed Central

    Xu, ChangJiang; Ladouceur, Martin; Dastani, Zari; Richards, J. Brent

    2012-01-01

    The investigation of associations between rare genetic variants and diseases or phenotypes has two goals. Firstly, the identification of which genes or genomic regions are associated, and secondly, discrimination of associated variants from background noise within each region. Over the last few years, many new methods have been developed which associate genomic regions with phenotypes. However, classical methods for high-dimensional data have received little attention. Here we investigate whether several classical statistical methods for high-dimensional data: ridge regression (RR), principal components regression (PCR), partial least squares regression (PLS), a sparse version of PLS (SPLS), and the LASSO are able to detect associations with rare genetic variants. These approaches have been extensively used in statistics to identify the true associations in data sets containing many predictor variables. Using genetic variants identified in three genes that were Sanger sequenced in 1998 individuals, we simulated continuous phenotypes under several different models, and we show that these feature selection and feature extraction methods can substantially outperform several popular methods for rare variant analysis. Furthermore, these approaches can identify which variants are contributing most to the model fit, and therefore both goals of rare variant analysis can be achieved simultaneously with the use of regression regularization methods. These methods are briefly illustrated with an analysis of adiponectin levels and variants in the ADIPOQ gene. PMID:22916111

  19. Dermascope assisted interactive patient interface for multiple reference optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Dsouza, Roshan; Subhash, Hrebesh; Neuhaus, Kai; Hogan, Josh; Wilson, Carol; Leahy, Martin

    2014-02-01

    There has been a growing interest in the development of a low cost depth-resolved non-invasive dermis imaging tool for both clinical and fundamental investigations of skin diseases. Multiple reference optical coherence tomography (MR-OCT) is a recently developed miniature time-domain low coherence interferometeric imaging platform, which promises to fit into robust, cost-effective designs that are virtually solid state, typical of handheld devices. In this paper we demonstrate the feasibility of MR-OCT for dermis imaging applications by incorporating it in a dermascope, which provides simultaneous imaging of dermis and an interactive tool for beam steering and registration of the OCT imaging beam at the dermis area. This allows the user to interactively investigate the depth resolved information of any target position of interest on the dermis by pointing the mouse cursor within the dermis image or selecting the area on a touch screen. Image acquisition is controlled with software that displays both the dermis and MR-OCT axial-scan, and allows detailed information of the depth scan signal to screen for skin disease. We believe this approach will have a significant impact on medical care.

  20. A study of retinal parameters measured by optical coherence tomography in patients with multiple sclerosis

    PubMed Central

    Hu, Sai-Jing; You, Yi-An; Zhang, Yi

    2015-01-01

    AIM To investigate the difference of retinal nerve fiber layer (RNFL) thickness and macular fovea thickness/volume between multiple sclerosis (MS) patients and healthy normal individuals using optical coherence tomography (OCT) and assess its association with visual field parameters. METHODS Thirty consecutive MS patients and 28 healthy controls were recruited in this prospective study. Comprehensive standardized ophthalmic examinations included visual acuity, cycloplegic refraction, intraocular pressure, gonioscopy, visual field, and RNFL thickness and macular fovea thickness/volume detection using Humphrey OCT. Mean values for the thickness of the peripapillary RNFL and macular volume were calculated. Associations between visual field parameters and RNFL thickness/macular volume were analyzed by Pearson correlation analysis. RESULTS The RNFL thicknesses in each quadrant, the average macular thickness, and the average macular volume in MS patients were all less than those in healthy controls, with statistically significant differences. The RNFL thickness and macular fovea thickness/volume were greater in eyes without optic neuritis than in eyes with optic neuritis. The average visual field parameters had positive correlations with the RNFL thickness and negative correlations with macular parameters in MS patients. CONCLUSION OCT measurements can effectively identify the nerve changes of MS patients, which provide more data for the diagnosis of MS. PMID:26682175

  1. Extracting multiple interacting root systems using X-ray microcomputed tomography.

    PubMed

    Mairhofer, Stefan; Sturrock, Craig J; Bennett, Malcolm J; Mooney, Sacha J; Pridmore, Tony P

    2015-12-01

    Root system interactions and competition for resources are active areas of research that contribute to our understanding of how roots perceive and react to environmental conditions. Recent research has shown this complex suite of processes can now be observed in a natural environment (i.e. soil) through the use of X-ray microcomputed tomography (?CT), which allows non-destructive analysis of plant root systems. Due to their similar X-ray attenuation coefficients and densities, the roots of different plants appear as similar greyscale intensity values in ?CT image data. Unless they are manually and carefully traced, it has not previously been possible to automatically label and separate different root systems grown in the same soil environment. We present a technique, based on a visual tracking approach, which exploits knowledge of the shape of root cross-sections to automatically recover from X-ray ?CT data three-dimensional descriptions of multiple, interacting root architectures growing in soil. The method was evaluated on both simulated root data and real images of two interacting winter wheat Cordiale (Triticumaestivum L.) plants grown in a single soil column, demonstrating that it is possible to automatically segment different root systems from within the same soil sample. This work supports the automatic exploration of supportive and competitive foraging behaviour of plant root systems in natural soil environments. PMID:26461469

  2. Hierarchical Bayesian regularization of reconstructions for diffuse optical tomography using multiple priors

    PubMed Central

    Abdelnour, Farras; Genovese, Christopher; Huppert, Theodore

    2010-01-01

    Diffuse optical tomography (DOT) is a non-invasive brain imaging technique that uses low-levels of near-infrared light to measure optical absorption changes due to regional blood flow and blood oxygen saturation in the brain. By arranging light sources and detectors in a grid over the surface of the scalp, DOT studies attempt to spatially localize changes in oxy- and deoxy-hemoglobin in the brain that result from evoked brain activity during functional experiments. However, the reconstruction of accurate spatial images of hemoglobin changes from DOT data is an ill-posed linearized inverse problem, which requires model regularization to yield appropriate solutions. In this work, we describe and demonstrate the application of a parametric restricted maximum likelihood method (ReML) to incorporate multiple statistical priors into the recovery of optical images. This work is based on similar methods that have been applied to the inverse problem for magnetoencephalography (MEG). Herein, we discuss the adaptation of this model to DOT and demonstrate that this approach provides a means to objectively incorporate reconstruction constraints and demonstrate this approach through a series of simulated numerical examples. PMID:21258532

  3. Voice coil based robust and miniature optical delay for multiple reference optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Dsouza, Roshan; Subhash, Hrebesh; Neuhaus, Kai; Hogan, Josh; Wilson, Carol; Leahy, Martin

    2014-02-01

    Multiple reference optical coherence tomography (MR-OCT) is a recently developed time-domain interferometeric imaging platform, which promises to fit into robust, cost-effective designs that are virtually solid state. An optical delay is created by the reference mirror which is mounted on a piezo-electric transducer (PZT) and the key element of MR-OCT technology is the presence of a partial mirror in front of the reference mirror. However, the limited axial displacement range at higher scanning-frequencies are a limitation of a PZT-based optical delay. Moreover, PZT-based actuators require a relatively high operational voltage and are expensive. In this paper we present a voice coil actuator as an alternative to a PZT-based optical delay. Voice coil actuators are light in weight, inexpensive and offer other advantages such as zero hysteresis, low operational voltage and a long life. We demonstrate a voice coil actuator as a feasible alternative to PZT-based actuators for the purpose of creating an optical delay, which can provide fast and precise axial displacements at high scanning rates.

  4. Magnetic resonance imaging for detecting lesions of multiple sclerosis: comparison with computed tomography and clinical assessment.

    PubMed Central

    Reese, L; Carr, T J; Nicholson, R L; Lepp, E K

    1986-01-01

    Eighty-two patients with known or suspected multiple sclerosis (MS) were examined by means of magnetic resonance imaging (MRI) with a 0.15-T resistive scanner. The diagnosis could be made by MRI in 34 (97%) of the 35 patients with chronic, well-documented, stable MS and by high-volume delayed x-ray computed tomography (HVD CT) in only 6 (54%) of 11 patients in this group. The stage of the disease as judged from the MRI scans correlated poorly with the clinical status of the patient and with the known duration of the disease. MRI identified 28 (88%) of the 32 patients in whom MS was subsequently diagnosed by a neurologist, whereas regular contrast or HVD CT identified only 11 (52%) of 21 such patients. MRI is the most sensitive imaging modality for MS but is of little value in assessing the severity of the disease: many of the lesions seen on MRI scans are clinically "silent", and MRI does not usually detect small lesions in the brainstem, cerebellum or spinal cord that may be clinically significant. Images Fig. 1A Fig. 1B Fig. 1C Fig. 1D Fig. 2 PMID:3756694

  5. Optical coherence tomography: a window into the mechanisms of multiple sclerosis

    PubMed Central

    Frohman, Elliot M; Fujimoto, James G; Frohman, Teresa C; Calabresi, Peter A; Cutter, Gary; Balcer, Laura J

    2009-01-01

    Summary The pathophysiology of multiple sclerosis (MS) is characterized by demyelination, which culminates in a reduction in axonal transmission. Axonal and neuronal degeneration seem to be concomitant features of MS and are probably the pathological processes responsible for permanent disability in this disease. The retina is unique within the CNS in that it contains axons and glia but no myelin, and it is, therefore, an ideal structure within which to visualize the processes of neurodegeneration, neuroprotection, and potentially even neurorestoration. In particular, the retina enables us to investigate a specific compartment of the CNS that is targeted by the disease process. Optical coherence tomography (OCT) can provide high-resolution reconstructions of retinal anatomy in a rapid and reproducible fashion and, we believe, is ideal for precisely modeling the disease process in MS. In this Review, we provide a broad overview of the physics of OCT, the unique properties of this method with respect to imaging retinal architecture, and the applications that are being developed for OCT to understand mechanisms of tissue injury within the brain. PMID:19043423

  6. P-wave travel-time tomography reveals multiple mantle upwellings beneath the northern East-Africa Rift

    NASA Astrophysics Data System (ADS)

    Hammond, J. O. S.; Civiero, C.; Goes, S. D. B.; Ahmed, A.; Ayele, A.; Doubre, C.; Goitom, B.; Keir, D.; Kendall, M.; Leroy, S. D.; Ogubazghi, G.; Rumpker, G.; Stuart, G. W.

    2014-12-01

    The East African Rift (EAR) shows evidence for active magmatism from the eruption of flood basalts 30 Ma to active volcanism associated with rifting today. Mantle plumes have been invoked as the likely cause. However, the nature of mantle upwelling is debated, with proposed models ranging from a single broad plume, the African Superplume, connected to the LLSVP beneath Southern Africa, to multiple distinct sources of upwelling along the East-Africa Rift. We present a new relative travel-time tomography model that images detailed P-wave velocities below the northern East-African rift from the surface to lower mantle depths. Data comes from 439 stations that cover the area from Tanzania to Saudi Arabia. The aperture of the integrated dataset allows us to image for the first time low-velocity structures of ~ 100-km length scales down to depths of 900 km beneath this region. Our images provide evidence of at least two separate low-velocity structures with a diameter of ~200 km that continue through the transition zone and into the lower mantle: the first, and most pronounced, is beneath the Afar Depression, which extends to at least 900 km depth and a second is located beneath the Main Ethiopian Rift that extends to at least 750 km. Taking into account seismic sensitivity to temperature and thermally controlled phase boundary topography, we interpret these features as multiple focused upwellings from below the transition zone with excess temperatures of ~ 100-150 K. Such temperatures are also fully consistent with previous petrological and other geophysical estimates. Furthermore, the separate structures could explain differences in geochemistry of erupted magmas along the rift zone, as well as the dynamic topography seen at the surface. Our findings thus support the involvement of multiple plumes in the evolution of the EAR and a direct connection between lower mantle features and the volcanism at the surface.

  7. Large variation in mitochondrial DNA of sexual and parthenogenetic Dahlica triquetrella (Lepidoptera: Psychidae) shows multiple origins of parthenogenesis

    PubMed Central

    2013-01-01

    Background Obligate parthenogenesis is relatively rare in animals. Still, in some groups it is quite common and has evolved and persisted multiple times. These groups may provide important clues to help solve the paradox of sex. Several species in the Psychidae (Lepidoptera) have obligate parthenogenesis. Dahlica triquetrella is one of those species where multiple transitions to parthenogenesis are postulated based on intensive cytological and behavioural studies. This has led to the hypothesis that multiple transitions from sexuals to diploid parthenogens occurred during and after the last glacial period, followed by transitions from parthenogenetic diploids to parthenogenetic tetraploids. Our study is the first to test these hypotheses using a molecular phylogeny based on mtDNA from multiple sexual and parthenogenetic populations from a wide geographic range. Results Parthenogenetic (and sexual) D. triquetrella are not monophyletic, and considerable sequence variation is present suggesting multiple transitions to parthenogenesis. However, we could not establish ancestral sexual haplotypes from our dataset. Our data suggest that some parthenogenetic clades have evolved, indicating origins of parthenogenesis before the last glacial period. Conclusions Multiple transitions to parthenogenesis have taken place in Dahlica triquetrella, confirming previous hypotheses. The number of different parthenogenetic clades, haplotypes and their apparent evolutionary age, clearly show that parthenogenesis has been a very successful reproductive strategy in this species over a long period. PMID:23622052

  8. A modified discrete algebraic reconstruction technique for multiple grey image reconstruction for limited angle range tomography.

    PubMed

    Liang, Zhiting; Guan, Yong; Liu, Gang; Chen, Xiangyu; Li, Fahu; Guo, Pengfei; Tian, Yangchao

    2016-03-01

    The `missing wedge', which is due to a restricted rotation range, is a major challenge for quantitative analysis of an object using tomography. With prior knowledge of the grey levels, the discrete algebraic reconstruction technique (DART) is able to reconstruct objects accurately with projections in a limited angle range. However, the quality of the reconstructions declines as the number of grey levels increases. In this paper, a modified DART (MDART) was proposed, in which each independent region of homogeneous material was chosen as a research object, instead of the grey values. The grey values of each discrete region were estimated according to the solution of the linear projection equations. The iterative process of boundary pixels updating and correcting the grey values of each region was executed alternately. Simulation experiments of binary phantoms as well as multiple grey phantoms show that MDART is capable of achieving high-quality reconstructions with projections in a limited angle range. The interesting advancement of MDART is that neither prior knowledge of the grey values nor the number of grey levels is necessary. PMID:26917150

  9. Optical Coherence Tomography Reflects Brain Atrophy in Multiple Sclerosis: A Four-Year Study

    PubMed Central

    Saidha, Shiv; Al-Louzi, Omar; Ratchford, John N.; Bhargava, Pavan; Oh, Jiwon; Newsome, Scott D.; Prince, Jerry L.; Pham, Dzung; Roy, Snehashis; van Zijl, Peter; Balcer, Laura J.; Frohman, Elliot M.; Reich, Daniel S.; Crainiceanu, Ciprian; Calabresi, Peter A.

    2015-01-01

    Objective The aim of this work was to determine whether atrophy of specific retinal layers and brain substructures are associated over time, in order to further validate the utility of optical coherence tomography (OCT) as an indicator of neuronal tissue damage in patients with multiple sclerosis (MS). Methods Cirrus high-definition OCT (including automated macular segmentation) was performed in 107 MS patients biannually (median follow-up: 46 months). Three-Tesla magnetic resonance imaging brain scans (including brain-substructure volumetrics) were performed annually. Individual-specific rates of change in retinal and brain measures (estimated with linear regression) were correlated, adjusting for age, sex, disease duration, and optic neuritis (ON) history. Results Rates of ganglion cell + inner plexiform layer (GCIP) and whole-brain (r = 0.45; p<0.001), gray matter (GM; r = 0.37; p<0.001), white matter (WM; r = 0.28; p = 0.007), and thalamic (r = 0.38; p < 0.001) atrophy were associated. GCIP and whole-brain (as well as GM and WM) atrophy rates were more strongly associated in progressive MS (r = 0.67; p<0.001) than relapsing-remitting MS (RRMS; r = 0.33; p = 0.007). However, correlation between rates of GCIP and whole-brain (and additionally GM and WM) atrophy in RRMS increased incrementally with step-wise refinement to exclude ON effects; excluding eyes and then patients (to account for a phenotype effect), the correlation increased to 0.45 and 0.60, respectively, consistent with effect modification. In RRMS, lesion accumulation rate was associated with GCIP (r = −0.30; p = 0.02) and inner nuclear layer (r = −0.25; p = 0.04) atrophy rates. Interpretation Over time GCIP atrophy appears to mirror whole-brain, and particularly GM, atrophy, especially in progressive MS, thereby reflecting underlying disease progression. Our findings support OCT for clinical monitoring and as an outcome in investigative trials. PMID:26190464

  10. An objective rationale for the choice of regularisation parameter with application to global multiple-frequency S-wave tomography

    NASA Astrophysics Data System (ADS)

    Zaroli, C.; Sambridge, M.; Lévêque, J.-J.; Debayle, E.; Nolet, G.

    2013-06-01

    In a linear ill-posed inverse problem, the regularisation parameter (damping) controls the balance between minimising both the residual data misfit and the model norm. Poor knowledge of data uncertainties often makes the selection of damping rather arbitrary. To go beyond that subjectivity, an objective rationale for the choice of damping is presented, which is based on the coherency of delay-time estimates in different frequency bands. Our method is tailored to the problem of global Multiple-Frequency Tomography (MFT), using a data set of 287 078 S-wave delay-times measured in five frequency bands (10, 15, 22, 34, 51 s central periods). Whereas for each ray path the delay-time estimates should vary coherently from one period to the other, the noise most likely is not coherent. Thus, the lack of coherency of the information in different frequency bands is exploited, using an analogy with the cross-validation method, to identify models dominated by noise. In addition, a sharp change of behaviour of the model ℓ∞-norm, as the damping becomes lower than a threshold value, is interpreted as the signature of data noise starting to significantly pollute at least one model component. Models with damping larger than this threshold are diagnosed as being constructed with poor data exploitation. Finally, a preferred model is selected from the remaining range of permitted model solutions. This choice is quasi-objective in terms of model interpretation, as the selected model shows a high degree of similarity with almost all other permitted models (correlation superior to 98% up to spherical harmonic degree 80). The obtained tomographic model is displayed in mid lower-mantle (660-1910 km depth), and is shown to be compatible with three other recent global shear-velocity models. A wider application of the presented rationale should permit us to converge towards more objective seismic imaging of the Earth's mantle.

  11. An objective rationale for the choice of regularisation parameter with application to global multiple-frequency S-wave tomography

    NASA Astrophysics Data System (ADS)

    Zaroli, C.; Sambridge, M.; Lévêque, J.-J.; Debayle, E.; Nolet, G.

    2013-10-01

    In a linear ill-posed inverse problem, the regularisation parameter (damping) controls the balance between minimising both the residual data misfit and the model norm. Poor knowledge of data uncertainties often makes the selection of damping rather arbitrary. To go beyond that subjectivity, an objective rationale for the choice of damping is presented, which is based on the coherency of delay-time estimates in different frequency bands. Our method is tailored to the problem of global multiple-frequency tomography (MFT), using a data set of 287 078 S-wave delay times measured in five frequency bands (10, 15, 22, 34, and 51 s central periods). Whereas for each ray path the delay-time estimates should vary coherently from one period to the other, the noise most likely is not coherent. Thus, the lack of coherency of the information in different frequency bands is exploited, using an analogy with the cross-validation method, to identify models dominated by noise. In addition, a sharp change of behaviour of the model ℓ∞-norm, as the damping becomes lower than a threshold value, is interpreted as the signature of data noise starting to significantly pollute at least one model component. Models with damping larger than this threshold are diagnosed as being constructed with poor data exploitation. Finally, a preferred model is selected from the remaining range of permitted model solutions. This choice is quasi-objective in terms of model interpretation, as the selected model shows a high degree of similarity with almost all other permitted models (correlation superior to 98% up to spherical harmonic degree 80). The obtained tomographic model is displayed in the mid lower-mantle (660-1910 km depth), and is shown to be compatible with three other recent global shear-velocity models. A wider application of the presented rationale should permit us to converge towards more objective seismic imaging of Earth's mantle.

  12. Monocular and binocular low-contrast visual acuity and optical coherence tomography in pediatric multiple sclerosis

    PubMed Central

    Waldman, Amy T.; Hiremath, Girish; Avery, Robert A.; Conger, Amy; Pineles, Stacy L.; Loguidice, Michael J.; Talman, Lauren S.; Galetta, Kristin M.; Shumski, Michael J.; Wilson, James; Ford, E'tona; Lavery, Amy M.; Conger, Darrel; Greenberg, Benjamin M.; Ellenberg, Jonas H.; Frohman, Elliot M.; Balcer, Laura J.; Calabresi, Peter A.

    2014-01-01

    Background Low-contrast letter acuity and optical coherence tomography (OCT) capture visual dysfunction and axonal loss in adult-onset multiple sclerosis (MS), and have been proposed as secondary outcome metrics for therapeutic trials. Clinical trials will soon be launched in pediatric MS, but such outcome metrics have not been well-validated in this population. Objectives To determine whether MS onset during childhood and adolescence is associated with measurable loss of visual acuity and thinning of the retinal nerve fiber layer (RNFL), whether such features are noted only in the context of clinical optic nerve inflammation (optic neuritis, ON) or are a feature of MS even in the absence of optic nerve relapses, and to define the optimal methods for such detection. Study design Cross-sectional study Methods Monocular and binocular high- and low-contrast letter acuity and contrast sensitivity were assessed in a cross-sectional cohort of children (ages 5 to 17 years) with MS (N=22 patients, 44 eyes; 8 patients with a history of ON) and disease-free controls (N=29 patients; 58 eyes) from three academic centers. Binocular summation was determined by calculating the number of letters correctly identified using the binocular score minus the better eye score for each visual test. RNFL thickness was measured using OCT (Stratus OCT-3). Results were analyzed in terms of “eyes” as: MS ON+, MS ON−, and control eyes. Generalized estimating equation (GEE) regression models were used to compare patients to controls. Results Traditional high-contrast visual acuity scores did not differ between MS ON+, MS ON−, and controls eyes. MS ON+ eyes had decreased monocular (p<0.001) and decreased binocular (p=0.007) low-contrast letter acuity (Sloan 1.25% contrast charts) scores. Monocular visual acuity did not differ when comparing MS ON− and control eyes. The magnitude of binocular summation using low-contrast charts was similar for pediatric MS participants and controls and was not diminished in children with a history of ON. While the mean RNFL thickness for all MS eyes (103±17 μm) trended lower when compared to corresponding measures in control eyes (109±9 μm, p=0.085), we confirmed a highly significant reduction in mean RNFL thickness in MS eyes with a history of ON (86±22 μm, p<0.001). RNFL thickness of MS ON− eyes in pediatric MS patients (109±11 μm) did not differ from controls (p=0.994). Conclusions Low-contrast letter acuity detects subtle visual loss in MS patients with prior ON, consistent with incomplete recovery, a finding further supported by RNFL loss in ON affected eyes. In MS patients with prior unilateral ON, binocular acuity is decreased; however, the magnitude of binocular summation is preserved, unlike adult-onset MS who exhibit a reduced capacity for visual compensation in the context of unilateral injury. Also unlike findings in adult-onset MS, we did not demonstrate RNFL thinning in ON− eyes of children and adolescents with MS. Further validation is required to confirm whether neurodegeneration of visual pathways occurs in the absence of relapse, and thus whether OCT will serve as a sensitive metric for such pathology in the pediatric and adolescent MS context. PMID:24683535

  13. InSAR time series shows multiple deformation and interaction of gravitational spreading, intrusion and compaction on Hawaii Island

    NASA Astrophysics Data System (ADS)

    Shirzaei, M.; Walter, T. R.

    2009-04-01

    Hawaii Island comprising some of the world most active volcanoes shows a complex deformation field. The two active volcanoes Mauna Loa and Kilauea are subject to magma emplacement and the islands' flanks are subject to gravitational spreading and landslide process. An island wide deformation analysis, however, and potential interaction of different sources was not systematically elaborated, yet. Using a newly developed Wavelet based InSAR time series (WAB-InSAR) approach we mapped the spatio-temporal deformation field in the period of 2003 and 2008. In this study we have utilized 30 radar images acquired by ENVISAT satellite in descending mode. The deformation time series shows different episodes of the uplift and subsidence over Mauna Loa and Kilauea volcano. At last to investigate the source of deformation we applied a time dependent non linear multiple source modeling approach based on continuous genetic algorithm. The result of this research show that volcano-tectonic signals are co-occurring, implying complex interaction of various process on Hawaii Island.

  14. A tetrahedron beam computed tomography benchtop system with a multiple pixel field emission x-ray tube

    SciTech Connect

    Xu, Xiaochao; Kim, Joshua; Laganis, Philip; Schulze, Derek; Liang, Yongguang; Zhang, Tiezhi

    2011-10-15

    Purpose: To demonstrate the feasibility of Tetrahedron Beam Computed Tomography (TBCT) using a carbon nanotube (CNT) multiple pixel field emission x-ray (MPFEX) tube. Methods: A multiple pixel x-ray source facilitates the creation of novel x-ray imaging modalities. In a previous publication, the authors proposed a Tetrahedron Beam Computed Tomography (TBCT) imaging system which comprises a linear source array and a linear detector array that are orthogonal to each other. TBCT is expected to reduce scatter compared with Cone Beam Computed Tomography (CBCT) and to have better detector performance. Therefore, it may produce improved image quality for image guided radiotherapy. In this study, a TBCT benchtop system has been developed with an MPFEX tube. The tube has 75 CNT cold cathodes, which generate 75 x-ray focal spots on an elongated anode, and has 4 mm pixel spacing. An in-house-developed, 5-row CT detector array using silicon photodiodes and CdWO{sub 4} scintillators was employed in the system. Hardware and software were developed for tube control and detector data acquisition. The raw data were preprocessed for beam hardening and detector response linearity and were reconstructed with an FDK-based image reconstruction algorithm. Results: The focal spots were measured at about 1 x 2 mm{sup 2} using a star phantom. Each cathode generates around 3 mA cathode current with 2190 V gate voltage. The benchtop system is able to perform TBCT scans with a prolonged scanning time. Images of a commercial CT phantom were successfully acquired. Conclusions: A prototype system was developed, and preliminary phantom images were successfully acquired. MPFEX is a promising x-ray source for TBCT. Further improvement of tube output is needed in order for it to be used in clinical TBCT systems.

  15. Detailed characterization of multiple myeloma circulating tumor cells shows unique phenotypic, cytogenetic, functional, and circadian distribution profile.

    PubMed

    Paiva, Bruno; Paino, Teresa; Sayagues, Jose-Maria; Garayoa, Mercedes; San-Segundo, Laura; Martn, Montserrat; Mota, Ines; Sanchez, Mara-Luz; Brcena, Paloma; Aires-Mejia, Irene; Corchete, Luis; Jimenez, Cristina; Garcia-Sanz, Ramon; Gutierrez, Norma C; Ocio, Enrique M; Mateos, Maria-Victoria; Vidriales, Maria-Belen; Orfao, Alberto; San Miguel, Jess F

    2013-11-21

    Circulating myeloma tumor cells (CTCs) as defined by the presence of peripheral blood (PB) clonal plasma cells (PCs) are a powerful prognostic marker in multiple myeloma (MM). However, the biological features of CTCs and their pathophysiological role in MM remains unexplored. Here, we investigate the phenotypic, cytogenetic, and functional characteristics as well as the circadian distribution of CTCs vs paired bone marrow (BM) clonal PCs from MM patients. Our results show that CTCs typically represent a unique subpopulation of all BM clonal PCs, characterized by downregulation (P < .05) of integrins (CD11a/CD11c/CD29/CD49d/CD49e), adhesion (CD33/CD56/CD117/CD138), and activation molecules (CD28/CD38/CD81). Fluorescence in situ hybridization analysis of fluorescence-activated cell sorter-sorted CTCs also unraveled different cytogenetic profiles vs paired BM clonal PCs. Moreover, CTCs were mostly quiescent and associated with higher clonogenic potential when cocultured with BM stromal cells. Most interestingly, CTCs showed a circadian distribution which fluctuates in a similar pattern to that of CD34(+) cells, and opposite to stromal cell-derived factor 1 plasma levels and corresponding surface expression of CXC chemokine receptor 4 on clonal PCs, suggesting that in MM, CTCs may egress to PB to colonize/metastasize other sites in the BM during the patients' resting period. PMID:24072855

  16. 18F-Fluorodeoxyglucose Positron-Emission Tomography Findings with Anti-N-Methyl-D-Aspartate Receptor Encephalitis that Showed Variable Degrees of Catatonia: Three Cases Report

    PubMed Central

    Lee, Eun Mi; Kang, Joong Koo; Oh, Jungsu S.; Kim, Jae Seung; Shin, Yong-Wook; Kim, Chang-Yoon

    2014-01-01

    Catatonia is one of the main symptoms of anti-N-Methyl-D-aspartate receptor (NMDAR) encephalitis. However, it is unknown whether metabolic changes observed with 18F-Fluorodeoxyglucose positron-emission tomography (FDG-PET) are correlated with the severity of the catatonic symptoms and clinical course. Three patients with anti-NMDAR encephalitis showing variable degrees of catatonia were performed with FDG-PET scans during the acute and recovery phase. PET findings showed hypermetabolism in the frontotemporoparietal regions and bilateral basal ganglia in the patient with mild catatonia, but more widespread hypermetabolic regions including the thalamus and brainstem were observed in the patients with more severe catatonia. Follow-up PET scans in one patient showed mild hypermetabolism in the right basal ganglia that correlated with mild rigidity and tonic posturing in the left extremities. Extent of cerebral metabolic changes correlates with the severity of catatonia accompanied by behavioural, motor, autonomic, and breathing abnormalities in anti-NMDAR encephalitis. PMID:25625091

  17. Multiple Rapid Swallow Maneuver Enhances the Clinical Utility of High-Resolution Manometry in Patients Showing Ineffective Esophageal Motility

    PubMed Central

    Min, Yang Won; Shin, Inseub; Son, Hee Jung; Rhee, Poong-Lyul

    2015-01-01

    Abstract The clinical significance of ineffective esophageal motility (IEM) together with multiple rapid swallow (MRS) has not been yet evaluated in the Chicago Classification v3.0. This study evaluated the adjunctive role of MRS in IEM and determined the criteria of abnormal MRS to maximize the utility of IEM. We analyzed 186 patients showing IEM or normal esophageal motility (NEM), who underwent esophageal high-resolution impedancemanometry for esophageal symptoms. Two different criteria for abnormal MRS were applied to IEM subjects, resulting in 2 corresponding subgroups: IEM-A when distal contractile integral (DCI) ratio between an average wet swallows and MRS contraction was <1 and IEM-B when MRS contraction DCI was <450?mm Hg-s-cm. One IEM subject inadequately performed MRS. Among the remaining 52 IEM subjects, 18 (34.6%) were classified into IEM-A and 23 (44.2%) into IEM-B. IEM subjects showed less complete bolus transit (median 0.0%, interquartile range 0.020.0% vs 60.0%, 30.080.0; P?showed additionally higher pathologic bolus exposure than NEM subjects (55.6% vs 29.3%, P?=?0.001), whereas IEM-A subjects could not. Although IEM-B subjects had the highest prevalence of gastroesophageal reflux disease among the subjects groups, it did not reach statistical significance. In conclusion, IEM patients with abnormal MRS contraction have an increased risk of prolonged bolus clearance, poor bolus transit, and pathologic bolus exposure. IEM patients need to be assessed concerning whether MRS contraction DCI is <450?mm Hg-s-cm to segregate clinically relevant patients. PMID:26448010

  18. Multiple Rapid Swallow Maneuver Enhances the Clinical Utility of High-Resolution Manometry in Patients Showing Ineffective Esophageal Motility.

    PubMed

    Min, Yang Won; Shin, Inseub; Son, Hee Jung; Rhee, Poong-Lyul

    2015-10-01

    The clinical significance of ineffective esophageal motility (IEM) together with multiple rapid swallow (MRS) has not been yet evaluated in the Chicago Classification v3.0. This study evaluated the adjunctive role of MRS in IEM and determined the criteria of abnormal MRS to maximize the utility of IEM. We analyzed 186 patients showing IEM or normal esophageal motility (NEM), who underwent esophageal high-resolution impedance-manometry for esophageal symptoms. Two different criteria for abnormal MRS were applied to IEM subjects, resulting in 2 corresponding subgroups: IEM-A when distal contractile integral (DCI) ratio between an average wet swallows and MRS contraction was < 1 and IEM-B when MRS contraction DCI was <450 mm Hg-s-cm. One IEM subject inadequately performed MRS. Among the remaining 52 IEM subjects, 18 (34.6%) were classified into IEM-A and 23 (44.2%) into IEM-B. IEM subjects showed less complete bolus transit (median 0.0%, interquartile range 0.0-20.0% vs 60.0%, 30.0-80.0; P < 0.001) resulting in higher impaired bolus transit than NEM subjects (98.1% vs 66.9%, P = 0.001). IEM-B subjects showed additionally higher pathologic bolus exposure than NEM subjects (55.6% vs 29.3%, P = 0.001), whereas IEM-A subjects could not. Although IEM-B subjects had the highest prevalence of gastroesophageal reflux disease among the subjects groups, it did not reach statistical significance. In conclusion, IEM patients with abnormal MRS contraction have an increased risk of prolonged bolus clearance, poor bolus transit, and pathologic bolus exposure. IEM patients need to be assessed concerning whether MRS contraction DCI is < 450 mm Hg-s-cm to segregate clinically relevant patients. PMID:26448010

  19. Fast linear solver for radiative transport equation with multiple right hand sides in diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Jia, Jingfei; Kim, Hyun K.; Hielscher, Andreas H.

    2015-12-01

    It is well known that radiative transfer equation (RTE) provides more accurate tomographic results than its diffusion approximation (DA). However, RTE-based tomographic reconstruction codes have limited applicability in practice due to their high computational cost. In this article, we propose a new efficient method for solving the RTE forward problem with multiple light sources in an all-at-once manner instead of solving it for each source separately. To this end, we introduce here a novel linear solver called block biconjugate gradient stabilized method (block BiCGStab) that makes full use of the shared information between different right hand sides to accelerate solution convergence. Two parallelized block BiCGStab methods are proposed for additional acceleration under limited threads situation. We evaluate the performance of this algorithm with numerical simulation studies involving the Delta-Eddington approximation to the scattering phase function. The results show that the single threading block RTE solver proposed here reduces computation time by a factor of 1.5-3 as compared to the traditional sequential solution method and the parallel block solver by a factor of 1.5 as compared to the traditional parallel sequential method. This block linear solver is, moreover, independent of discretization schemes and preconditioners used; thus further acceleration and higher accuracy can be expected when combined with other existing discretization schemes or preconditioners.

  20. [A Case Strongly Suspected of Being Pulmonary Toxocariasis Showing Multiple Pulmonary Nodules with a Disappearing and Reappearing Halo Sign].

    PubMed

    Takakura, Akira; Harada, Shinya; Katono, Ken; Igawa, Satoshi; Katagiri, Masato; Yanase, Nobuo; Masuda, Noriyuki

    2015-03-01

    We report herein on a case strongly suspected of being pulmonary toxocariasis. A 22-year-old Indonesian man referred to our hospital presented with abnormal chest shadows upon medical examination. He had no symptoms. He did not have any pets nor did he eat raw beef or chicken. Hematological examination revealed eosinophilia and elevation of IgE. Chest computed tomography revealed 3 pulmonary nodules with the halo sign. We suspected a parasite infection and performed antiparasite antibody testing. Ascaris suum was slightly positive on the screening test. As specific antibody against the larval excretory-secretory products of Toxocara canis, measured at the National Institute of Infectious Diseases, was positive (level 3 up to 8). Subsequently, the abnormal chest shadows disappeared. However, two months later, 2 pulmonary nodules with the halo sign reappeared in other places. Diagnostic therapy with albendazole was performed for 8 weeks. Mild hepatic impairment emerged during therapy, but it was within the allowed range. Thereafter, the results improved for the imaging findings, eosinophilia, serum IgE level, and specific antibody. The antibody level became negative two months after the treatment had ended. We should consider toxocariasis in the differential diagnosis of migratory nodular shadows with the halo sign on chest computed tomography, and immunoserological testing is useful for the diagnosis. PMID:26552124

  1. An Objective Rationale for the Choice of Regularisation Parameter with Application to Global Multiple-Frequency S-Wave Tomography

    NASA Astrophysics Data System (ADS)

    Zaroli, C.; Sambridge, M.; Leveque, J. J.; Debayle, E.; Nolet, G.

    2014-12-01

    In a linear ill-posed inverse problem, the regularisation parameter (damping) controls the balance between minimising both the residual data misfit and the model norm. Poor knowledge of data uncertainties often makes the selection of damping rather arbitrary. To go beyond that subjectivity, an objective rationale for the choice of damping is presented, which is based on the coherency of delay-time estimates in different frequency bands. Our method is tailored to the problem of global Multiple-Frequency Tomography, using a data set of 287078 S-wave delay-times measured in five frequency bands (10, 15, 22, 34, 51 s central periods). Whereas for each ray path the delay-time estimates should vary coherently from one period to the other, the noise most likely is not coherent. Thus, the lack of coherency of the information in different frequency bands is exploited, using an analogy with the cross-validation method, to identify models dominated by noise.In addition, a sharp change of behaviour of the model infinity-norm, as the damping becomes lower than a threshold value, is interpreted as the signature of data noise starting to significantly pollute at least one model component. Models with damping larger than this threshold are diagnosed as being constructed with poor data exploitation.Finally, a preferred model is selected from the remaining range of permitted model solutions. This choice is quasi-objective in terms of model interpretation, as the selected model shows a high degree of similarity with almost all other permitted models. The obtained tomographic model is displayed in mid lower-mantle (660-1910 km depth), and is shown to be mostly compatible with three other recent global shear-velocity models, while significant differences can be noticed. A wider application of the presented rationale should permit us to converge towards more objective seismic imaging of the Earth's mantle, using as much as possible of the relevant structural information in the data. This work was recently published: Zaroli, C., Sambridge, M., Lévêque, J.-J., Debayle, E., and Nolet, G. (2013) - Solid Earth, 4, 357-371, doi:10.5194/se-4-357-2013

  2. A Novel Immunofluorescent Computed Tomography (ICT) Method to Localise and Quantify Multiple Antigens in Large Tissue Volumes at High Resolution

    PubMed Central

    Parfitt, Geraint J.; Xie, Yilu; Reid, Korey M.; Dervillez, Xavier; Brown, Donald J.; Jester, James V.

    2012-01-01

    Current immunofluorescence protocols are limited as they do not provide reliable antibody staining within large tissue volumes (mm3) and cannot localise and quantify multiple antigens or cell populations in the same tissue at high resolution. To address this limitation, we have developed an approach to three-dimensionally visualise large tissue volumes (mm3) at high resolution (<1 µm) and with multiple antigen labelling, for volumetric and quantitative analysis. This is made possible through computer reconstruction of serial sectioned and sequentially immunostained butyl-methyl methacrylate (BMMA) embedded tissue. Using this novel immunofluorescent computed tomography (ICT) approach, we have three-dimensionally reconstructed part of the murine lower eyelid that contains the meibomian gland and localised cell nuclei (DAPI), Ki67 and cytokeratin 1 (CK1), as well as performing non-linear optical (NLO) microscopy imaging of collagen, to assess cell density, cell proliferation, gland keratinisation and gland volume respectively. Antigenicity was maintained after four iterative stains on the same tissue, suggesting that there is no defined limit to the number of antigens that can be immunostained for reconstruction, as long as the sections remain intact and the previous antibody has been successfully eluted. BMMA resin embedding also preserved fluorescence of transgenic proteins. We propose that ICT may provide valuable high resolution, three-dimensional biological maps of multiple biomolecules within a single tissue or organ to better characterise and quantify tissue structure and function. PMID:23300899

  3. A Finite Element Mesh Aggregating Approach to Multiple-Source Reconstruction in Bioluminescence Tomography

    PubMed Central

    Yu, Jingjing; Liu, Fang; Jiao, L. C.; Yang, Shuyuan; He, Xiaowei

    2011-01-01

    A finite element mesh aggregating approach is presented to reconstruct images of multiple internal bioluminescence sources. Rather than assuming independence between mesh nodes, the proposed reconstruction strategy exploits spatial structure of nodes and aggregation feature of density distribution on the finite element mesh to adaptively determine the number of sources and to improve the quality of reconstructed images. With the proposed strategy integrated in the regularization-based reconstruction process, reconstruction algorithms need no a priori knowledge of source number; even more importantly, they can automatically reconstruct multiple sources that differ greatly in density or power. PMID:22144980

  4. Organic anion transporter 2 transcript variant 1 shows broad ligand selectivity when expressed in multiple cell lines

    PubMed Central

    Hotchkiss, Adam G.; Berrigan, Liam; Pelis, Ryan M.

    2015-01-01

    Organic anion transporter 2 (OAT2) is likely important for renal and hepatic drug elimination. Three variants of the OAT2 peptide sequence have been described – OAT2 transcript variant 1 (OAT2-tv1), OAT2 transcript variant 2 (OAT2-tv2), and OAT2 transcript variant 3 (OAT2-tv3). Early studies helping to define the ligand selectivity of OAT2 failed to identify the variant used, and the studies used several heterologous expression systems. In preliminary studies using OAT2-tv1, we failed to observe transport of several previously identified substrates, leading us to speculate that ligand selectivity of OAT2 differs with variant and/or heterologous expression system. The purpose was to further investigate the ligand selectivity of the OAT2 variants expressed in multiple cell types. We cloned OAT2-tv1 and OAT2-tv2, but were unsuccessful at amplifying mRNA for OAT2-tv3 from human kidney. OAT2-tv1 and OAT2-tv2 were individually expressed in human embryonic kidney (HEK), Madin-Darby canine kidney (MDCK), or Chinese hamster ovary (CHO) cells. mRNA for OAT2-tv1 and OAT2-tv2 was demonstrated in each cell type transfected with the respective construct, indicating their expression. OAT2-tv1 trafficked to the plasma membrane of all three cell types, but OAT2-tv2 did not. OAT2-tv1 transported penciclovir in all three cell types, but failed to transport para-aminohippurate, succinate, glutarate, estrone-3-sulfate, paclitaxel or dehydroepiandrosterone sulfate – previously identified substrates of OAT2-tv2. Not surprising given its lack of plasma membrane expression, OAT2-tv2 failed to transport any of the organic solutes examined, including penciclovir. Penciclovir transport by OAT2-tv1 was sensitive to large (e.g., cyclosporine A) and small (e.g., allopurinol) organic compounds, as well as organic anions, cations and neutral compounds, highlighting the multiselectivity of OAT2-tv1. The potencies with which indomethacin, furosemide, cyclosporine A and cimetidine inhibited OAT2-tv1 are in good agreement with previous studies using this variant, but inconsistent with studies using OAT2 with an unidentified sequence. This study shows that organic molecules with diverse physicochemical properties interact with OAT2-tv1, making it a likely site of drug interactions. Many previously identified substrates of OAT2 are not transported by OAT2-tv1, suggesting that variant and/or expression system may contribute. Future work should establish the expression pattern and ligand selectivity of OAT2-tv3. PMID:26500550

  5. Hardware Implementation of Multiple Fan Beam Projection Technique in Optical Fibre Process Tomography

    PubMed Central

    Rahim, Ruzairi Abdul; Fazalul Rahiman, Mohd Hafiz; Leong, Lai Chen; Chan, Kok San; Pang, Jon Fea

    2008-01-01

    The main objective of this project is to implement the multiple fan beam projection technique using optical fibre sensors with the aim to achieve a high data acquisition rate. Multiple fan beam projection technique here is defined as allowing more than one emitter to transmit light at the same time using the switch-mode fan beam method. For the thirty-two pairs of sensors used, the 2-projection technique and 4-projection technique are being investigated. Sixteen sets of projections will complete one frame of light emission for the 2-projection technique while eight sets of projection will complete one frame of light emission for the 4-projection technique. In order to facilitate data acquisition process, PIC microcontroller and the sample and hold circuit are being used. This paper summarizes the hardware configuration and design for this project.

  6. A least-squares fixed-point iterative algorithm for multiple illumination photoacoustic tomography

    PubMed Central

    Harrison, Tyler; Shao, Peng; Zemp, Roger J.

    2013-01-01

    The optical absorption of tissues provides important information for clinical and pre-clinical studies. The challenge in recovering optical absorption from photoacoustic images is that the measured pressure depends on absorption and local fluence. One reconstruction approach uses a fixed-point iterative technique based on minimizing the mean-squared error combined with modeling of the light source to determine optical absorption. With this technique, convergence is not guaranteed even with an accurate measure of optical scattering. In this work we demonstrate using simulations that a new multiple illumination least squares fixed-point iteration algorithm improves convergence - even with poor estimates of optical scattering. PMID:24156078

  7. Effect of Statin Therapy in 4-Year-Old Dichorionic Diamniotic Twins with Familial Hypercholesterolemia Showing Multiple Xanthomas.

    PubMed

    Miyagi, Yoshitsune; Harada-Shiba, Mariko; Ohta, Takao

    2016-01-01

    Familial hypercholesterolemia (FH) is characterized by a high level of low-density lipoprotein cholesterol (LDL-C) and is inherited as an autosomal dominant trait. We report 4-year-old dichorionic diamniotic twins (boy and girl) with FH who presented with multiple xanthomas on the face, both knees, both feet, and buttocks. Family history revealed vertical transmission of hypercholesterolemia from father to patients, thereby suggesting dominant inheritance. Lipid data of their mother did not match the criteria of FH. However, lipid data of maternal grandmother and maternal sister matched the criteria of FH. LDL receptor gene analysis of the family revealed that their father was heterozygous for a missense mutation, L547V, their mother was heterozygous for a nonsense mutation, C675X, and patients were compound heterozygous for L547V and C675X. After 10 months of treatment with pitavastatin (2 mg/day) and ezetimibe (10 mg/day), LDL-C decreased from 595 mg/dL to 267 mg/dL in the boy and from 530 mg/dL to 182 mg/dL in the girl. These findings suggest that lipid-lowering therapy with statin may be considered in pediatric patients with compound heterozygous FH (hetero FH) before inducing LDL apheresis, and gene analysis for true diagnosis in pediatric patients with multiple xanthomas should be considered, though they appear to be hetero FH from the family history and lipid data of parents. PMID:26510755

  8. Nuclear and Chloroplast Microsatellites Show Multiple Introductions in the Worldwide Invasion History of Common Ragweed, Ambrosia artemisiifolia

    PubMed Central

    Gaudeul, Myriam; Giraud, Tatiana; Kiss, Levente; Shykoff, Jacqui A.

    2011-01-01

    Background Ambrosia artemisiifolia is a North American native that has become one of the most problematic invasive plants in Europe and Asia. We studied its worldwide population genetic structure, using both nuclear and chloroplast microsatellite markers and an unprecedented large population sampling. Our goals were (i) to identify the sources of the invasive populations; (ii) to assess whether all invasive populations were founded by multiple introductions, as previously found in France; (iii) to examine how the introductions have affected the amount and structure of genetic variation in Europe; (iv) to document how the colonization of Europe proceeded; (v) to check whether populations exhibit significant heterozygote deficiencies, as previously observed. Principal Findings We found evidence for multiple introductions of A. artemisiifolia, within regions but also within populations in most parts of its invasive range, leading to high levels of diversity. In Europe, introductions probably stem from two different regions of the native area: populations established in Central Europe appear to have originated from eastern North America, and Eastern European populations from more western North America. This may result from differential commercial exchanges between these geographic regions. Our results indicate that the expansion in Europe mostly occurred through long-distance dispersal, explaining the absence of isolation by distance and the weak influence of geography on the genetic structure in this area in contrast to the native range. Last, we detected significant heterozygote deficiencies in most populations. This may be explained by partial selfing, biparental inbreeding and/or a Wahlund effect and further investigation is warranted. Conclusions This insight into the sources and pathways of common ragweed expansion may help to better understand its invasion success and provides baseline data for future studies on the evolutionary processes involved during range expansion in novel environments. PMID:21423697

  9. A bi-dimensional genome scan for prolificacy traits in pigs shows the existence of multiple epistatic QTL

    PubMed Central

    2009-01-01

    Background Prolificacy is the most important trait influencing the reproductive efficiency of pig production systems. The low heritability and sex-limited expression of prolificacy have hindered to some extent the improvement of this trait through artificial selection. Moreover, the relative contributions of additive, dominant and epistatic QTL to the genetic variance of pig prolificacy remain to be defined. In this work, we have undertaken this issue by performing one-dimensional and bi-dimensional genome scans for number of piglets born alive (NBA) and total number of piglets born (TNB) in a three generation Iberian by Meishan F2 intercross. Results The one-dimensional genome scan for NBA and TNB revealed the existence of two genome-wide highly significant QTL located on SSC13 (P < 0.001) and SSC17 (P < 0.01) with effects on both traits. This relative paucity of significant results contrasted very strongly with the wide array of highly significant epistatic QTL that emerged in the bi-dimensional genome-wide scan analysis. As much as 18 epistatic QTL were found for NBA (four at P < 0.01 and five at P < 0.05) and TNB (three at P < 0.01 and six at P < 0.05), respectively. These epistatic QTL were distributed in multiple genomic regions, which covered 13 of the 18 pig autosomes, and they had small individual effects that ranged between 3 to 4% of the phenotypic variance. Different patterns of interactions (a a, a d, d a and d d) were found amongst the epistatic QTL pairs identified in the current work. Conclusions The complex inheritance of prolificacy traits in pigs has been evidenced by identifying multiple additive (SSC13 and SSC17), dominant and epistatic QTL in an Iberian Meishan F2 intercross. Our results demonstrate that a significant fraction of the phenotypic variance of swine prolificacy traits can be attributed to first-order gene-by-gene interactions emphasizing that the phenotypic effects of alleles might be strongly modulated by the genetic background where they segregate. PMID:20040109

  10. Experiments with the nonlinear and chaotic behaviour of the multiplicative algebraic reconstruction technique (MART) algorithm for computed tomography

    NASA Astrophysics Data System (ADS)

    Badea, Cristian; Gordon, Richard

    2004-04-01

    Among the iterative reconstruction algorithms for tomography, the multiplicative algebraic reconstruction technique (MART) has two advantages that make it stand out from other algorithms: it confines the image (and therefore the projection data) to the convex hull of the patient, and it maximizes entropy. In this paper, we have undertaken a series of experiments to determine the importance of MART nonlinearity to image quality. Variants of MART were implemented aiming to exploit and exaggerate the nonlinear properties of the algorithm. We introduce the Power MART, Boxcar Averaging MART and Bouncing MART algorithms. Power MART is linked to the relaxation concept. Its behaviour is similar to that of the chaos of a logistic equation. There appears to be an antagonism between increasing nonlinearity and noise in the projection data. The experiments confirm our general observation that regularization as a means of solving simultaneous linear equations that are underdetermined is suboptimal: it does not necessarily select the correct image from the hyperplane of solutions, and so does not maximize the image quality:x-ray dose ratio. Our investigations prove that there is scope to optimize CT algorithms and thereby achieve greater dose reduction.

  11. Experiments with the nonlinear and chaotic behaviour of the multiplicative algebraic reconstruction technique (MART) algorithm for computed tomography.

    PubMed

    Badea, Cristian; Gordon, Richard

    2004-04-21

    Among the iterative reconstruction algorithms for tomography, the multiplicative algebraic reconstruction technique (MART) has two advantages that make it stand out from other algorithms: it confines the image (and therefore the projection data) to the convex hull of the patient, and it maximizes entropy. In this paper, we have undertaken a series of experiments to determine the importance of MART nonlinearity to image quality. Variants of MART were implemented aiming to exploit and exaggerate the nonlinear properties of the algorithm. We introduce the Power MART, Boxcar Averaging MART and Bouncing MART algorithms. Power MART is linked to the relaxation concept. Its behaviour is similar to that of the chaos of a logistic equation. There appears to be an antagonism between increasing nonlinearity and noise in the projection data. The experiments confirm our general observation that regularization as a means of solving simultaneous linear equations that are underdetermined is suboptimal: it does not necessarily select the correct image from the hyperplane of solutions, and so does not maximize the image quality:x-ray dose ratio. Our investigations prove that there is scope to optimize CT algorithms and thereby achieve greater dose reduction. PMID:15152685

  12. 3D nondestructive testing system with an affordable multiple reference optical-delay-based optical coherence tomography.

    PubMed

    Dsouza, Roshan; Subhash, Hrebesh M; Neuhaus, Kai; Hogan, Josh; Wilson, Carol; Leahy, Martin

    2015-06-20

    Optical coherence tomography (OCT) is emerging as a powerful noncontact imaging technique, allowing high-quality cross-sectional imaging of scattering specimens nondestructively. However, the complexity and cost of current embodiments of an OCT system limit its use in various nondestructive testing (NDT) applications at resource-limited settings. In this paper, we demonstrate the feasibility of a novel low-cost OCT system for a range of nondestructive testing (NDT) applications. The proposed imaging system is based on an enhanced time-domain OCT system with a low cost and small form factor reference arm optical delay, called multiple reference OCT (MR-OCT), which uses a miniature voice coil actuator and a partial mirror for extending the axial scan range. The proposed approach is potentially a low-cost, compact, and unique optical imaging modality for a range of NDT applications in a low-resource setting. Using this method, we demonstrated the capability of MR-OCT to perform cross-sectional and volumetric imaging at 1200 A-scans per second. PMID:26193006

  13. Rationally engineered nanoparticles target multiple myeloma cells, overcome cell-adhesion-mediated drug resistance, and show enhanced efficacy in vivo

    PubMed Central

    Kiziltepe, T; Ashley, J D; Stefanick, J F; Qi, Y M; Alves, N J; Handlogten, M W; Suckow, M A; Navari, R M; Bilgicer, B

    2012-01-01

    In the continuing search for effective cancer treatments, we report the rational engineering of a multifunctional nanoparticle that combines traditional chemotherapy with cell targeting and anti-adhesion functionalities. Very late antigen-4 (VLA-4) mediated adhesion of multiple myeloma (MM) cells to bone marrow stroma confers MM cells with cell-adhesion-mediated drug resistance (CAM-DR). In our design, we used micellar nanoparticles as dynamic self-assembling scaffolds to present VLA-4-antagonist peptides and doxorubicin (Dox) conjugates, simultaneously, to selectively target MM cells and to overcome CAM-DR. Dox was conjugated to the nanoparticles through an acid-sensitive hydrazone bond. VLA-4-antagonist peptides were conjugated via a multifaceted synthetic procedure for generating precisely controlled number of targeting functionalities. The nanoparticles were efficiently internalized by MM cells and induced cytotoxicity. Mechanistic studies revealed that nanoparticles induced DNA double-strand breaks and apoptosis in MM cells. Importantly, multifunctional nanoparticles overcame CAM-DR, and were more efficacious than Dox when MM cells were cultured on fibronectin-coated plates. Finally, in a MM xenograft model, nanoparticles preferentially homed to MM tumors with ?10 fold more drug accumulation and demonstrated dramatic tumor growth inhibition with a reduced overall systemic toxicity. Altogether, we demonstrate the disease driven engineering of a nanoparticle-based drug delivery system, enabling the model of an integrative approach in the treatment of MM. PMID:22829966

  14. Simultaneous Joint Inversion of Multiple Geophysical Data Sets and 3D Tomography

    NASA Astrophysics Data System (ADS)

    Maceira, M.; Rowe, C. A.; Borchers, B.; Steck, L. K.

    2008-12-01

    We present the results of our efforts to model the 3D seismic shear wave velocity structure by simultaneously and jointly inverting multiple geophysical observations. It has long been recognized that derivation of geophysical models for a given observable, such as body wave models or surface wave models, may provide good predictors of behavior for the specific parameter modeled, but often provides poor prediction capabilities for other parameters, even when we have empirical or theoretical knowledge of how the parameters relate to one another. Due to the non-unique properties of inversion methods, often we may find a solution for one data type but we must acknowledge that, although it can predict behavior of that data type, the solution is ambiguous and other models may serve equally well. Thus a joint, simultaneous inversion of all pertinent and available data types for a region may provide us with a far more robust model than obtained by using only a single parameter. Moreover, the extent of our well-resolved model may be significantly expanded due to the variable coverage provided by different measurements, and its features may be better constrained due to the different resolving powers of different data types. We are exploring the 3D seismic structure of a small portion of the Tarim Basin in northwest China using simultaneous joint inversion of surface wave group velocities, teleseismic P-wave receiver functions, S-wave travel times, and Bouguer gravity anomaly observations derived from the Gravity Recovery And Climate Experiment (GRACE) mission. An iterative, conjugate gradient-based least squares inversion is used to jointly model the four different data sets, using shear-velocity variations as the primary model parameters. Improved knowledge of the shear velocity structure of the Asian continent is of fundamental importance for understanding the geodynamic evolution and formation of continents and the processes acting within and on the continental lithosphere.

  15. αβ T-cell receptors from multiple sclerosis brain lesions show MAIT cell–related features

    PubMed Central

    Held, Kathrin; Bhonsle-Deeng, Latika; Siewert, Katherina; Sato, Wakiro; Beltrán, Eduardo; Schmidt, Stephan; Rühl, Geraldine; Ng, Judy K.M.; Engerer, Peter; Moser, Markus; Klinkert, Wolfgang E.F.; Babbe, Holger; Misgeld, Thomas; Wekerle, Hartmut; Laplaud, David-Axel; Hohlfeld, Reinhard

    2015-01-01

    Objectives: To characterize phenotypes of T cells that accumulated in multiple sclerosis (MS) lesions, to compare the lesional T-cell receptor (TCR) repertoire of T-cell subsets to peripheral blood, and to identify paired α and β chains from single CD8+ T cells from an index patient who we followed for 18 years. Methods: We combined immunohistochemistry, laser microdissection, and single-cell multiplex PCR to characterize T-cell subtypes and identify paired TCRα and TCRβ chains from individual brain-infiltrating T cells in frozen brain sections. The lesional and peripheral TCR repertoires were analyzed by pyrosequencing. Results: We found that a TCR Vβ1+ T-cell population that was strikingly expanded in active brain lesions at clinical onset comprises several subclones expressing distinct yet closely related Vα7.2+ α chains, including a canonical Vα7.2-Jα33 chain of mucosal-associated invariant T (MAIT) cells. Three other α chains bear striking similarities in their antigen-recognizing, hypervariable complementarity determining region 3. Longitudinal repertoire studies revealed that the TCR chains that were massively expanded in brain at onset persisted for several years in blood or CSF but subsequently disappeared except for the canonical Vα7.2+ MAIT cell and a few other TCR sequences that were still detectable in blood after 18 years. Conclusions: Our observation that a massively expanded TCR Vβ1-Jβ2.3 chain paired with distinct yet closely related canonical or atypical MAIT cell–related α chains strongly points to an antigen-driven process in early active MS brain lesions. PMID:25977934

  16. Healthy Older Observers Show Equivalent Perceptual-Cognitive Training Benefits to Young Adults for Multiple Object Tracking

    PubMed Central

    Legault, Isabelle; Allard, Rmy; Faubert, Jocelyn

    2013-01-01

    The capacity to process complex dynamic scenes is of critical importance in real life. For instance, traveling through a crowd while avoiding collisions and maintaining orientation and good motor control requires fluent and continuous perceptual-cognitive processing. It is well documented that effects of healthy aging can influence perceptual-cognitive processes (Faubert, 2002) and that the efficiency of such processes can improve with training even for older adults (Richards et al., 2006). Here we assess the capacity of older participants to improve their tracking speed thresholds in a dynamic, virtual reality environment. Results show that this capacity is significantly affected by healthy aging but that perceptual-cognitive training can significantly reduce age-related effects in older individuals, who show an identical learning function to younger healthy adults. Data support the notion that learning in healthy older persons is maintained for processing complex dynamic scenes. PMID:23761025

  17. The Impact of Utilizing Different Optical Coherence Tomography Devices for Clinical Purposes and in Multiple Sclerosis Trials

    PubMed Central

    Warner, Christina V.; Syc, Stephanie B.; Stankiewicz, Aleksandra M.; Hiremath, Girish; Farrell, Sheena K.; Crainiceanu, Ciprian M.; Conger, Amy; Frohman, Teresa C.; Bisker, Esther R.; Balcer, Laura J.; Frohman, Elliot M.; Calabresi, Peter A.; Saidha, Shiv

    2011-01-01

    Optical coherence tomography (OCT) derived retinal measures, particularly peri-papillary retinal nerve fiber layer (RNFL) thickness, have been proposed as outcome measures in remyelinating and neuroprotective trials in multiple sclerosis (MS). With increasing utilization of multiple centers to improve power, elucidation of the impact of different OCT technologies is crucial to the design and interpretation of such studies. In this study, we assessed relation and agreement between RNFL thickness and total macular volume (in MS and healthy controls) derived from three commonly used OCT devices: Stratus time-domain OCT, and Cirrus HD-OCT and Spectralis, two spectral-domain (SD) OCT devices. OCT was performed on both Cirrus HD-OCT and Stratus in 229 participants and on both Cirrus HD-OCT and Spectralis in a separate cohort of 102 participants. Pearson correlation and Bland-Altman analyses were used to assess correlation and agreement between devices. All OCT retinal measures correlated highly between devices. The mean RNFL thickness was 7.4 µm lower on Cirrus HD-OCT than Stratus, indicating overall poor agreement for this measurement between these machines. Further, the limits of agreement (LOA) between Cirrus HD-OCT and Stratus were wide (−4.1 to 18.9 µm), indicating poor agreement at an individual subject level. The mean RNFL thickness was 1.94 µm (LOA: −5.74 to 9.62 µm) higher on Spectralis compared to Cirrus HD-OCT, indicating excellent agreement for this measurement across this cohort. Although these data indicate that these three devices agree poorly at an individual subject level (evidenced by wide LOA in both study cohorts) precluding their co-utilization in everyday practice, the small difference for mean measurements between Cirrus HD-OCT and Spectralis indicate pooled results from these two SD-devices could be used as outcome measures in clinical trials, provided patients are scanned on the same machine throughout the trial, similar to the utilization of multiple different MRI platforms in MS clinical trials. PMID:21853058

  18. The olive flounder (Paralichthys olivaceus) Pax3 homologues are highly conserved, encode multiple isoforms and show unique expression patterns.

    PubMed

    Jiao, Shuang; Tan, Xungang; Wang, Qian; Li, Meijie; Du, Shao Jun

    2015-02-01

    Pax genes encode a highly conserved family of transcription factors that play crucial roles in the formation of tissues and organs during development. Pax3 plays crucial roles in patterning of the dorsal central nervous system (CNS), neural crest and skeletal muscle. Here, we identified two spliced isoforms of Pax3a and three spliced isoforms of Pax3b and characterized their expression patterns. Both of flounder Pax3a-1 and Pax3b-1 contain the conserved paired domain (PD), an octapeptide motif (OP), and a paired type homeodomain (HD). But the PD domain in Pax3a-2 and Pax3b-3 is not intact and there is no HD in Pax3b-2 and Pax3b-3. Pax3a and Pax3b show distinct temporal expression patterns during embryogenesis. Whole-mount in situ hybridization demonstrates that Pax3a and Pax3b are expressed in overlapping patterns in the dorsal central nervous system, with some subtle regional differences between the two genes. In addition, Pax3a is scattered in the somites while Pax3b is specifically expressed in the newly forming somites. RT-PCR results have shown that there were different expression patterns between the different isoforms. These results indicate subfunction partitioning of the duplicated Pax3 genes. The duplicated Pax3 may provide additional flexibility in fine-tuning neurogenesis and somitogenesis. PMID:25448050

  19. Simultaneous multiple wavelength fluorescence video microscopy shows Ca2+ regulation of pH in living cells

    NASA Astrophysics Data System (ADS)

    Morris, Stephen J.; Beatty, Diane M.; Chronwall, Bibie M.

    1994-08-01

    We have designed an epifluorescence video microscope for simultaneous dual excitation of indo 1 (for [Ca2+]i) at 350 nm and SNARF 1 (for pHi) at 540 nm. The microscope will simultaneously capture all four emission images at 405, 475, 575, and 640 nm from the two ratio dyes at video frame or field rates. Popular dyes for measuring [Ca2+]i, such as indo 1 and fura 2, have pH- dependent Kd's; thus changes in pHi can be misinterpreted as changes in [Ca2+]i. For any pixel (or region of interest), we use the pH value to generate the appropriate Kd. The corrected Kd is then used to calculate a corrected calcium value. Using the imaging system, we show that, for the peptide secreting melanotropes of the pituitary intermediate lobe, changes in intracellular calcium ([Ca2PLU)]i) produce changes in intracellular pH (pHi). Melanotropes grown in primary explant culture and double-loaded with indo-1 acetoxy methyl ester (AM) and SNARF-1 AM, were examined for Ca2+/pH interactions. Following experimentation, cells were positively identified by (beta) -endorphin fluorescence immunohistochemistry. K-induced depolarization of melanotropes produced increases in [Ca2PLU)]i due to activation of L-type Ca-channels. Ca2+ entry was closely coupled to reductions in pHi. Effects were dependent upon entry of extracellular Ca2+ rather than release from intracellular stores. The close association between increases in intracellular Ca2+ and H+ suggest that the pHi changes are due to release of H+ upon binding of Ca2+ to intracellular buffers. Although the pH drop is `passive,' it will be sensed by all cytoplasmic components. Thus it represents a second messenger pathway, akin to the generation of cAMP or inositol trisphosphate, which cannot fail to influence numerous pH-dependent cell activities.

  20. Clinical and prognostic significance of bone marrow abnormalities in the appendicular skeleton detected by low-dose whole-body multidetector computed tomography in patients with multiple myeloma

    PubMed Central

    Nishida, Y; Matsue, Y; Suehara, Y; Fukumoto, K; Fujisawa, M; Takeuchi, M; Ouchi, E; Matsue, K

    2015-01-01

    Clinical significance of medullary abnormalities in the appendicular skeleton (AS) detected by low-dose whole-body multidetector computed tomography (MDCT) in patients with multiple myeloma (MM) was investigated. A total of 172 patients with monoclonal gammopathy of undetermined significance (MGUS) (n=17), smoldering MM (n=47) and symptomatic MM (n=108) underwent low-dose MDCT. CT values (CTv) of medullary density of AS?0 Hounsfield unit (HU) was considered as abnormal. Percentage of medullary abnormalities and the mean CTv of AS in patients with MGUS, smoldering MM and symptomatic MM were 18, 55 and 62% and ?44.5?, ?20.3 and 11.2?HU, respectively (P<0.001 and P<0.001). Disease progression of MM was independently associated with high CTv on multivariate analysis. In symptomatic MM, the presence of abnormal medullary lesions was associated with increased incidence of high-risk cytogenetic abnormalities (34.4% vs 7.7% P=0.002) and extramedullary disease (10.4% vs 0% P=0.032). It was also an independent poor prognostic predictor (hazard ratio 3.546, P=0.04). This study showed that CTv of AS by MDCT is correlated with disease progression of MM, and the presence of abnormal medullary lesions is a predictor for poor survival. PMID:26230953

  1. Simultaneous multiplicative column-normalized method (SMART) for 3-D ionosphere tomography in comparison to other algebraic methods

    NASA Astrophysics Data System (ADS)

    Gerzen, T.; Minkwitz, D.

    2016-01-01

    The accuracy and availability of satellite-based applications like GNSS positioning and remote sensing crucially depends on the knowledge of the ionospheric electron density distribution. The tomography of the ionosphere is one of the major tools to provide link specific ionospheric corrections as well as to study and monitor physical processes in the ionosphere. In this paper, we introduce a simultaneous multiplicative column-normalized method (SMART) for electron density reconstruction. Further, SMART+ is developed by combining SMART with a successive correction method. In this way, a balancing between the measurements of intersected and not intersected voxels is realised. The methods are compared with the well-known algebraic reconstruction techniques ART and SART. All the four methods are applied to reconstruct the 3-D electron density distribution by ingestion of ground-based GNSS TEC data into the NeQuick model. The comparative case study is implemented over Europe during two periods of the year 2011 covering quiet to disturbed ionospheric conditions. In particular, the performance of the methods is compared in terms of the convergence behaviour and the capability to reproduce sTEC and electron density profiles. For this purpose, independent sTEC data of four IGS stations and electron density profiles of four ionosonde stations are taken as reference. The results indicate that SMART significantly reduces the number of iterations necessary to achieve a predefined accuracy level. Further, SMART+ decreases the median of the absolute sTEC error up to 15, 22, 46 and 67 % compared to SMART, SART, ART and NeQuick respectively.

  2. Multiple mantle upwellings beneath the Northern East-African Rift System from relative P- and S-wave traveltime tomography

    NASA Astrophysics Data System (ADS)

    Civiero, Chiara; Hammond, James; Goes, Saskia; Fishwick, Stewart; Ahmed, Abdulhakim; Ayele, Atalay; Doubre, Cecile; Goitom, Berhe; Keir, Derek; Kendall, Mike; Leroy, Sylvie; Ogubazghi, Ghebrebrhan; Rumpker, Georg; Stuart, Graham

    2015-04-01

    Mantle plumes have been invoked as the likely cause of East African Rift volcanism and extension. However, the nature of mantle upwelling is debated, with proposed configurations ranging from a single broad plume, the African Superplume, connected to the LLSVP beneath Southern Africa, to one or more distinct lower-mantle sources along the rift. We present a new relative travel-time tomography model that images detailed P- and S- wave velocities from P,S and SKS phases below the northern East-African, Red Sea and Gulf of Aden rift. Data comes from stations that cover the area from Tanzania to Saudi Arabia. The aperture of the integrated dataset allows us to image for the first time structures of ~100 km length scale down to depths of 900 km beneath this region. Our images provide evidence of at least two low-velocity structures with a diameter of ~200 km that continue through the transition zone and into the lower mantle: the first extends to at least 900 km beneath Afar, and a second reaching at least 750 km depth just west of the Main Ethiopian Rift, a region with off-rift volcanism. Taking into account seismic sensitivity to temperature and thermally controlled phase boundary topography, we interpret these features as multiple focused upwellings from below the transition zone with excess temperatures of 100±50 K. The scale of the upwellings is smaller than any of the previously proposed lower mantle plume sources. This suggests the ponding or flow of deep-plume material below the transition zone may be spawning smaller upper-mantle upwellings.

  3. Radiation Treatment Planning Using Positron Emission and Computed Tomography for Lung and Pharyngeal Cancers: A Multiple-Threshold Method for [{sup 18}F]Fluoro-2-Deoxyglucose Activity

    SciTech Connect

    Okubo, Mitsuru; Nishimura, Yasumasa; Nakamatsu, Kiyoshi; Okumura, Masahiko R.T.; Shibata, Toru; Kanamori, Shuichi; Hanaoka, Kouhei R.T.; Hosono, Makoto

    2010-06-01

    Purpose: Clinical applicability of a multiple-threshold method for [{sup 18}F]fluoro-2-deoxyglucose (FDG) activity in radiation treatment planning was evaluated. Methods and Materials: A total of 32 patients who underwent positron emission and computed tomography (PET/CT) simulation were included; 18 patients had lung cancer, and 14 patients had pharyngeal cancer. For tumors of <=2 cm, 2 to 5 cm, and >5 cm, thresholds were defined as 2.5 standardized uptake value (SUV), 35%, and 20% of the maximum FDG activity, respectively. The cervical and mediastinal lymph nodes with the shortest axial diameter of >=10 mm were considered to be metastatic on CT (LNCT). The retropharyngeal lymph nodes with the shortest axial diameter of >=5 mm on CT and MRI were also defined as metastatic. Lymph nodes showing maximum FDG activity greater than the adopted thresholds for radiation therapy planning were designated LNPET-RTP, and lymph nodes with a maximum FDG activity of >=2.5 SUV were regarded as malignant and were designated LNPET-2.5 SUV. Results: The sizes of gross tumor volumes on PET (GTVPET) with the adopted thresholds in the axial plane were visually well fitted to those of GTV on CT (GTVCT). However, the volumes of GTVPET were larger than those of GTVCT, with significant differences (p < 0.0001) for lung cancer, due to respiratory motion. For lung cancer, the numbers of LNCT, LNPET-RTP, and LNPET-2.5 SUV were 29, 28, and 34, respectively. For pharyngeal cancer, the numbers of LNCT, LNPET-RTP, and LNPET-2.5 SUV were 14, 9, and 15, respectively. Conclusions: Our multiple thresholds were applicable for delineating the primary target on PET/CT simulation. However, these thresholds were inaccurate for depicting malignant lymph nodes.

  4. Dose reduction in whole-body computed tomography of multiple injuries (DoReMI): protocol for a prospective cohort study

    PubMed Central

    2014-01-01

    Background Single-pass, contrast-enhanced whole body multidetector computed tomography (MDCT) emerged as the diagnostic standard for evaluating patients with major trauma. Modern iterative image algorithms showed high image quality at a much lower radiation dose in the non-trauma setting. This study aims at investigating whether the radiation dose can safely be reduced in trauma patients without compromising the diagnostic accuracy and image quality. Methods/Design Prospective observational study with two consecutive cohorts of patients. Setting: A high-volume, academic, supra-regional trauma centre in Germany. Study population: Consecutive male and female patients who 1. had been exposed to a high-velocity trauma mechanism, 2. present with clinical evidence or high suspicion of multiple trauma (predicted Injury Severity Score [ISS] ?16) and 3. are scheduled for primary MDCT based on the decision of the trauma leader on call. Imaging protocols: In a before/after design, a consecutive series of 500 patients will undergo single-pass, whole-body 128-row multi-detector computed tomography (MDCT) with a standard, as low as possible radiation dose. This will be followed by a consecutive series of 500 patients undergoing an approved ultra-low dose MDCT protocol using an image processing algorithm. Data: Routine administrative data and electronic patient records, as well as digital images stored in a picture archiving and communications system will serve as the primary data source. The protocol was approved by the institutional review board. Main outcomes: (1) incidence of delayed diagnoses, (2) diagnostic accuracy, as correlated to the reference standard of a synopsis of all subsequent clinical, imaging, surgical and autopsy findings, (3) patients safety, (4) radiation exposure (e.g. effective dose), (5) subjective image quality (assessed independently radiologists and trauma surgeons on a 100-mm visual analogue scale), (6) objective image quality (e.g., contrast-to-noise ratio). Analysis: Multivariate regression will be employed to adjust and correct the findings for time and cohort effects. An exploratory interim analysis halfway after introduction of low-dose MDCT will be conducted to assess whether this protocol is clearly inferior or superior to the current standard. Discussion Although non-experimental, this study will generate first large-scale data on the utility of imaging-enhancing algorithms in whole-body MDCT for major blunt trauma. Trial registration Current Controlled Trials ISRCTN74557102. PMID:24589310

  5. Organ dose measurements from multiple-detector computed tomography using a commercial dosimetry system and tomographic, physical phantoms

    NASA Astrophysics Data System (ADS)

    Lavoie, Lindsey K.

    The technology of computed tomography (CT) imaging has soared over the last decade with the use of multi-detector CT (MDCT) scanners that are capable of performing studies in a matter of seconds. While the diagnostic information obtained from MDCT imaging is extremely valuable, it is important to ensure that the radiation doses resulting from these studies are at acceptably safe levels. This research project focused on the measurement of organ doses resulting from modern MDCT scanners. A commercially-available dosimetry system was used to measure organ doses. Small dosimeters made of optically-stimulated luminescent (OSL) material were analyzed with a portable OSL reader. Detailed verification of this system was performed. Characteristics studied include energy, scatter, and angular responses; dose linearity, ability to erase the exposed dose and ability to reuse dosimeters multiple times. The results of this verification process were positive. While small correction factors needed to be applied to the dose reported by the OSL reader, these factors were small and expected. Physical, tomographic pediatric and adult phantoms were used to measure organ doses. These phantoms were developed from CT images and are composed of tissue-equivalent materials. Because the adult phantom is comprised of numerous segments, dosimeters were placed in the phantom at several organ locations, and doses to select organs were measured using three clinical protocols: pediatric craniosynostosis, adult brain perfusion and adult cardiac CT angiography (CTA). A wide-beam, 320-slice, volumetric CT scanner and a 64-slice, MDCT scanner were used for organ dose measurements. Doses ranged from 1 to 26 mGy for the pediatric protocol, 1 to 1241 mGy for the brain perfusion protocol, and 2-100 mGy for the cardiac protocol. In most cases, the doses measured on the 64-slice scanner were higher than those on the 320-slice scanner. A methodology to measure organ doses with OSL dosimeters received from CT imaging has been presented. These measurements are especially important in keeping with the ALARA (as low as reasonably achievable) principle. While diagnostic information from CT imaging is valuable and necessary, the dose to patients is always a consideration. This methodology aids in this important task. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

  6. Can we use Electrical Resistivity Tomography to measure root zone moisture dynamics in fields with multiple crops?

    NASA Astrophysics Data System (ADS)

    Garre, S.; Coteur, I.; Wongleecharoen, C.; Diels, J.; Vanderborght, J.

    2012-12-01

    Agriculture on shallow or steep soils in the humid tropics often leads to low resource use efficiency. Contour hedgerow intercropping systems have been proposed to reduce run-off and control soil erosion. However, competition for water and nutrients between crops and associated hedgerows may reduce the overall performance of contour hedgerow systems. Electrical resistivity tomography (ERT) is a valuable technique to assess the distribution and dynamics of soil moisture non-invasively. Root water uptake is a spatially variable and small-scale process, which requires at least decimeter resolution and a high sensitivity in order to be able to monitor changes in time and space. Careful experimental design is of uttermost importance in order to maximize the information content of the ERT survey and to gain insights in the possibilities and limitations of the survey. Virtual experiments in combination with absolute and spatial performance measures provide a way to optimize the information that can be retrieved from an ERT experiment. We used this approach to identify a suitable measurement methodology to monitor water fluxes in a contour hedgerow intercropping system in Ratchaburi province, Thailand. The virtual experiment showed that there are important differences between the tested measurement configurations. We saw that the optimal ERT array was capable of recognizing distinct water depletion zones under the different crops. However, sharp contrasts in the 1-D water depletion profile are smoothened. ERT measurements conducted in Thailand showed that the soils of our experimental plots were very heterogeneous both along the slope as with depth. This observation highlighted some constraints of the ERT method for soil moisture monitoring in the field, such as the difficulty to define a relationship between electrical conductivity and soil moisture in very heterogeneous soils. Nevertheless, the data indeed revealed contrasting water depletion patterns under monocropping and intercropping systems. ERT allowed us to access information about the vadose zone moisture dynamics that would be unavailable with classical soil moisture measurements.

  7. Dual modality optical coherence and whole-body photoacoustic tomography imaging of chick embryos in multiple development stages

    PubMed Central

    Liu, Mengyang; Maurer, Barbara; Hermann, Boris; Zabihian, Behrooz; Sandrian, Michelle G.; Unterhuber, Angelika; Baumann, Bernhard; Zhang, Edward Z.; Beard, Paul C.; Weninger, Wolfgang J.; Drexler, Wolfgang

    2014-01-01

    Chick embryos are an important animal model for biomedical studies. The visualization of chick embryos, however, is limited mostly to postmortem sectional imaging methods. In this work, we present a dual modality optical imaging system that combines swept-source optical coherence tomography and whole-body photoacoustic tomography, and apply it to image chick embryos at three different development stages. The explanted chick embryos were imaged in toto with complementary contrast from both optical scattering and optical absorption. The results serve as a prelude to the use of the dual modality system in longitudinal whole-body monitoring of chick embryos in ovo. PMID:25401028

  8. Event-related potentials to tones show differences between children with multiple risk factors for dyslexia and control children before the onset of formal reading instruction.

    PubMed

    Hmlinen, Jarmo A; Lohvansuu, Kaisa; Ervast, Leena; Leppnen, Paavo H T

    2015-02-01

    Multiple risk factors can affect the development of specific reading problems or dyslexia. In addition to the most prevalent and studied risk factor, phonological processing, auditory discrimination problems have also been found in children and adults with reading difficulties. The present study examined 37 children between the ages of 5 and 6, 11 of which had multiple risk factors for developing reading problems. The children participated in a passive oddball EEG experiment with sinusoidal sounds with changes in sound frequency, duration, or intensity. The responses to the standard stimuli showed a negative voltage shift in children at risk for reading problems compared to control children at 107-215 ms in frontocentral areas corresponding to P1 offset and N250 onset. Source analyses showed that the difference originated from the left and right auditory cortices. Additionally, the children at risk for reading problems had a larger late discriminative negativity (LDN) response in amplitude for sound frequency change than the control children. The amplitudes at the P1-N250 time window showed correlations to letter knowledge and phonological identification whereas the amplitudes at the LDN time window correlated with verbal short-term memory and rapid naming. These results support the view that problems in basic auditory processing abilities precede the onset of reading instruction and can act as one of the risk factors for dyslexia. PMID:24746550

  9. Meaning of Interior Tomography

    PubMed Central

    Wang, Ge; Yu, Hengyong

    2013-01-01

    The classic imaging geometry for computed tomography is for collection of un-truncated projections and reconstruction of a global image, with the Fourier transform as the theoretical foundation that is intrinsically non-local. Recently, interior tomography research has led to theoretically exact relationships between localities in the projection and image spaces and practically promising reconstruction algorithms. Initially, interior tomography was developed for x-ray computed tomography. Then, it has been elevated as a general imaging principle. Finally, a novel framework known as omni-tomography is being developed for grand fusion of multiple imaging modalities, allowing tomographic synchrony of diversified features. PMID:23912256

  10. Double-tracer, multiple-organ transaxial emission computed tomography: improved localization and characterization of radiotracer distributions. [Dogs

    SciTech Connect

    Holman, B.L.; Hill, T.C.; Lovett, R.D.; Shulkin, P.; Zimmerman, R.E.

    1980-05-01

    Transaxial emission computed tomography (ECT) was performed in dogs with experimentally induced abscesses, using /sup 67/Ga and several /sup 99m/Tc-labeled organ-specific radiopharmaceuticals. Superimposition of /sup 99m/Tc ECT images onto the /sup 67/Ga uptake, correctly localizing a perinephric abscess, a splenic abscess, and a focus of osteomyelitis. This technique also permits further characterization or regions of decreased activity.

  11. Correlative Tomography

    NASA Astrophysics Data System (ADS)

    Burnett, T. L.; McDonald, S. A.; Gholinia, A.; Geurts, R.; Janus, M.; Slater, T.; Haigh, S. J.; Ornek, C.; Almuaili, F.; Engelberg, D. L.; Thompson, G. E.; Withers, P. J.

    2014-04-01

    Increasingly researchers are looking to bring together perspectives across multiple scales, or to combine insights from different techniques, for the same region of interest. To this end, correlative microscopy has already yielded substantial new insights in two dimensions (2D). Here we develop correlative tomography where the correlative task is somewhat more challenging because the volume of interest is typically hidden beneath the sample surface. We have threaded together x-ray computed tomography, serial section FIB-SEM tomography, electron backscatter diffraction and finally TEM elemental analysis all for the same 3D region. This has allowed observation of the competition between pitting corrosion and intergranular corrosion at multiple scales revealing the structural hierarchy, crystallography and chemistry of veiled corrosion pits in stainless steel. With automated correlative workflows and co-visualization of the multi-scale or multi-modal datasets the technique promises to provide insights across biological, geological and materials science that are impossible using either individual or multiple uncorrelated techniques.

  12. Correlative Tomography

    PubMed Central

    Burnett, T. L.; McDonald, S. A.; Gholinia, A.; Geurts, R.; Janus, M.; Slater, T.; Haigh, S. J.; Ornek, C.; Almuaili, F.; Engelberg, D. L.; Thompson, G. E.; Withers, P. J.

    2014-01-01

    Increasingly researchers are looking to bring together perspectives across multiple scales, or to combine insights from different techniques, for the same region of interest. To this end, correlative microscopy has already yielded substantial new insights in two dimensions (2D). Here we develop correlative tomography where the correlative task is somewhat more challenging because the volume of interest is typically hidden beneath the sample surface. We have threaded together x-ray computed tomography, serial section FIB-SEM tomography, electron backscatter diffraction and finally TEM elemental analysis all for the same 3D region. This has allowed observation of the competition between pitting corrosion and intergranular corrosion at multiple scales revealing the structural hierarchy, crystallography and chemistry of veiled corrosion pits in stainless steel. With automated correlative workflows and co-visualization of the multi-scale or multi-modal datasets the technique promises to provide insights across biological, geological and materials science that are impossible using either individual or multiple uncorrelated techniques. PMID:24736640

  13. Individual voxel-based analysis of brain magnetization transfer maps shows great variability of gray matter injury in the first stage of multiple sclerosis.

    PubMed

    Jure, Lorena; Zaaraoui, Wafaa; Rousseau, Celia; Reuter, Franoise; Rico, Audrey; Malikova, Irina; Confort-Gouny, Sylviane; Cozzone, Patrick J; Pelletier, Jean; Ranjeva, Jean-Philippe; Audoin, Bertrand

    2010-08-01

    In multiple sclerosis (MS), it seems likely that the variability of the long-term disability might be partly due to the variability of the early gray matter (GM) injury. In the present study, we assessed the variability of GM injury in early MS, using a method designed to determine individual pathological GM patterns. Eighteen patients presenting with a clinically isolated syndrome and 24 healthy matched control subjects were included in this study. Patients were explored using a 1.5 Tesla MR scanner (Magnetom Vision Plus; Siemens). Brain MR protocol included magnetization transfer ratio imaging (MTR). Statistical mapping analyses were performed to compare each subject's GM MTR maps with those of the whole group of control subjects (SPM5). The statistical threshold was taken to be the maximum P value showing no significant cluster when any control individual was compared with the whole control population. GM abnormalities were observed in 83% of the patients, ranging in size from 0.3 to 125 cm(3). Among the patients with GM abnormalities, 87% had abnormalities located in the temporal cortex, 80% in the frontal cortex, 80% in the limbic cortex, 73% in the posterior fossa, 53% in the deep GM, 47% in the parietal cortex, and 47% in the occipital cortex. Individual statistical mapping of MTR data, which gives a quantitative assessment of individual GM lesions, demonstrates great variability of grey matter injury in the first stage of multiple sclerosis. PMID:20677272

  14. [A case of septic pulmonary embolism showing the rapid appearance of multiple cavities in both lung fields induced by urinary tract infection].

    PubMed

    Miyaki, Junya; Souma, Shinya; Narumiya, Yasuyuki; Chiba, Shigehiro; Kugiyama, Kiyotaka

    2006-11-01

    A 69-year-old man who had benign prostatic hypertrophy and hypertension was admitted to our hospital because of urinary retention and high grade fever. Chest radiograph showed the appearance of multiple cavitating nodules in both lung fields within a few days after admission. Staphylococcus aureus was isolated in blood and sputum cultures, though there were no pathogens in urine culture. Abdominal CT demonstrated bilateral hydronephrosis. Since we could not detect any other infectious focuses such as bacterial endocarditis, septic thrombophlebitis etc., we reached the diagnosis of septic pulmonary embolism (SPE) induced by urinary tract infection (UTI). After diagnosis, the patient was given intravenous meropenem, ciprofloxacin, sulbactam/ampicilin, and recovered. Although several cases of SPE induced by UTI in diabetes mellitus patients have been reported, the present case who had no severe underlying disorder is very rare. PMID:17144591

  15. Multiple antigen peptide containing B and T cell epitopes of F1 antigen of Yersinia pestis showed enhanced Th1 immune response in murine model.

    PubMed

    Ali, R; Naqvi, R A; Kumar, S; Bhat, A A; Rao, D N

    2013-05-01

    Yersinia pestis is a facultative bacterium that can survive and proliferate inside host macrophages and cause bubonic, pneumonic and systemic infection. Apart from humoral response, cell-mediated protection plays a major role in combating the disease. Fraction 1 capsular antigen (F1-Ag) of Y.pestis has long been exploited as a vaccine candidate. In this study, F1-multiple antigenic peptide (F1-MAP or MAP)-specific cell-mediated and cytokine responses were studied in murine model. MAP consisting of three B and one T cell epitopes of F1-antigen with one palmitoyl residue was synthesized using Fmoc chemistry. Mice were immunized with different formulations of MAP in poly DL-lactide-co-glycolide (PLGA) microspheres. F1-MAP with CpG oligodeoxynucleotide (CpG-ODN) as an adjuvant showed enhanced in vitro T cell proliferation and Th1 (IL-2, IFN-? and TNF-?) and Th17 (IL-17A) cytokine secretion. Similar formulation also showed significantly higher numbers of cytokine (IL-2, IFN-?)-secreting cells. Moreover, F1-MAP with CpG formulation showed significantly high (P<0.001) percentage of CD4(+) IFN-?(+) cells as compared to CD8(+) IFN-?(+) cells, and also more (CD4- IFN-?)(+) cells secrete perforin and granzyme as compared to (CD8- IFN-?)(+) showing Th1 response. Thus, the study highlights the importance of Th1 cytokine and existence of CD4(+) and CD8(+) immune response. This study proposes a new perspective for the development of vaccination strategies for Y.pestis that trigger T cell immune response. PMID:23480362

  16. Intravascular gas in multiple organs detected by postmortem computed tomography: effect of prolonged cardiopulmonary resuscitation on organ damage in patients with cardiopulmonary arrest.

    PubMed

    Zenda, Takahiro; Takayama, Teruhiko; Miyamoto, Masaji; Yamaguchi, Shizuko; Endo, Tamao; Inaba, Hideo

    2011-02-01

    A 76-year-old woman was found in cardiopulmonary arrest with her head submerged in water in a bathtub. Despite cardiopulmonary resuscitation (CPR) for over 1 h by professional emergency technicians and medical doctors, the patient died. Postmortem computed tomography revealed not only pulmonary edema associated with drowning but also the presence of intravascular gas in the pulmonary artery, liver, kidneys, heart (right ventricle), and brain. It was speculated that intravascular gas was generated and spread to multiple organs during CPR procedures via the alimentary tract and lungs, which had been damaged by ischemia after cardiopulmonary arrest. Prolonged CPR procedures may involve the risk of additional organ damage and systemic air emboli. PMID:21359941

  17. Pseudoaneurysm Arising from Mitral Aortic Intervalvular Fibrosa (P-MAIVF) Communicating with Left Atrium (LA): Multiple Detector Computed Tomography (MDCT) Evaluation

    PubMed Central

    Mittal, Kartik; Agrawal, Rajat; Dey, Amit K.; Gadewar, Rohit; Dadhania, Divyesh; Hira, Priya

    2015-01-01

    Summary Background The entity pseudoaneurysm arising from the mitral aortic intervalvular fibrosa (P-MAIVF) is a rare cardiac finding caused by multiple factors. This entity is usually diagnosed with echocardiography and confirmed with cardiac computed tomography (CT). Case Report We presented a case of congenital P-MAIVF communicating with the left atrium (LA) and an aberrant right subclavian artery, misdiagnosed as primary mitral regurgitation (MR) in transthoracic echocardiogram (TTE) due to relative contraindications to transesophageal echocardiogram (TEE), revealed in a hemophilic patient, and diagnosed with cardiac CT. Conclusions In conclusion, cardiac CT plays a definitive role not only in anatomical assessment and confirmation of the lesion but also in primary diagnostics in patients suspected of MAIVF especially those with relative and absolute contraindications to TEE. PMID:25745522

  18. Multiple imaging mode X-ray computed tomography for distinguishing active and inactive phases in lithium-ion battery cathodes

    NASA Astrophysics Data System (ADS)

    Komini Babu, Siddharth; Mohamed, Alexander I.; Whitacre, Jay F.; Litster, Shawn

    2015-06-01

    This paper presents the use of nanometer scale resolution X-ray computed tomography (nano-CT) in the three-dimensional (3D) imaging of a Li-ion battery cathode, including the separate volumes of active material, binder plus conductive additive, and pore. The different high and low atomic number (Z) materials are distinguished by sequentially imaging the lithium cobalt oxide electrode in absorption and then Zernike phase contrast modes. Morphological parameters of the active material and the additives are extracted from the 3D reconstructions, including the distribution of contact areas between the additives and the active material. This method could provide a better understanding of the electric current distribution and structural integrity of battery electrodes, as well as provide detailed geometries for computational models.

  19. Myalgic encephalomyelitis/chronic fatigue syndrome and encephalomyelitis disseminata/multiple sclerosis show remarkable levels of similarity in phenomenology and neuroimmune characteristics

    PubMed Central

    2013-01-01

    Background ‘Encephalomyelitis disseminata’ (multiple sclerosis) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are both classified as diseases of the central nervous system by the World Health Organization. This review aims to compare the phenomenological and neuroimmune characteristics of MS with those of ME/CFS. Discussion There are remarkable phenomenological and neuroimmune overlaps between both disorders. Patients with ME/CFS and MS both experience severe levels of disabling fatigue and a worsening of symptoms following exercise and resort to energy conservation strategies in an attempt to meet the energy demands of day-to-day living. Debilitating autonomic symptoms, diminished cardiac responses to exercise, orthostatic intolerance and postural hypotension are experienced by patients with both illnesses. Both disorders show a relapsing-remitting or progressive course, while infections and psychosocial stress play a large part in worsening of fatigue symptoms. Activated immunoinflammatory, oxidative and nitrosative (O+NS) pathways and autoimmunity occur in both illnesses. The consequences of O+NS damage to self-epitopes is evidenced by the almost bewildering and almost identical array of autoantibodies formed against damaged epitopes seen in both illnesses. Mitochondrial dysfunctions, including lowered levels of ATP, decreased phosphocreatine synthesis and impaired oxidative phosphorylation, are heavily involved in the pathophysiology of both MS and ME/CFS. The findings produced by neuroimaging techniques are quite similar in both illnesses and show decreased cerebral blood flow, atrophy, gray matter reduction, white matter hyperintensities, increased cerebral lactate and choline signaling and lowered acetyl-aspartate levels. Summary This review shows that there are neuroimmune similarities between MS and ME/CFS. This further substantiates the view that ME/CFS is a neuroimmune illness and that patients with MS are immunologically primed to develop symptoms of ME/CFS. PMID:24229326

  20. Multiple medullary venous malformations decreasing cerebral blood flow: Case report

    SciTech Connect

    Tomura, N.; Inugami, A.; Uemura, K.; Hadeishi, H.; Yasui, N. )

    1991-02-01

    A rare case of multiple medullary venous malformations in the right cerebral hemisphere is reported. The literature review yielded only one case of multiple medullary venous malformations. Computed tomography scan showed multiple calcified lesions with linear contrast enhancement representing abnormal dilated vessels and mild atrophic change of the right cerebral hemisphere. Single-photon emission computed tomography using N-isopropyl-p-({sup 123}I) iodoamphetamine demonstrated decreased cerebral blood flow in the right cerebral hemisphere.

  1. The tyrosinase-positive oculocutaneous albinism gene shows locus homogeneity on chromosome 15q11-q13 and evidence of multiple mutations in southern African negroids

    SciTech Connect

    Kedda, M.A.; Stevens, G.; Manga, P.; Viljoen, C.; Jenkins, T.; Ramsay, M. Univ. of Witwatersrand, Johannesburg )

    1994-06-01

    Tyrosinase-positive oculocutaneous albinism (ty-pos OCA) is an autosomal recessive disorder of the melanin pigmentary system. South African ty-pos OCA individuals occur with two distinct phenotypes, with or without darkly pigmented patches (ephelides, or dendritic freckles) on exposed areas of the skin. These phenotypes are concordant within families, suggesting that there may be more than one mutation at the ty-pos OCA locus. Linkage studies carried out in 41 families have shown linkage between markers in the Prader-Willi/Angelman syndrome (PWS/AS) region on chromosome 15q11-q13 and ty-pos OCA. Analysis showed no obligatory crossovers between the alleles at the D15S12 locus and ty-pos OCA, suggesting that the D15S12 locus is very close to or part of the disease locus, which is postulated to be the human homologue, P, of the mouse pink-eyed dilution gene, p. Unlike caucasoid [open quotes]ty-pos OCA[close quotes] individuals, negroid ty-pos OCA individuals do not show any evidence of locus heterogeneity. Studies of allelic association between the polymorphic alleles detected at the D15S12 locus and ephelus status suggest that there was a single major mutation giving rise to ty-pos OCA without ephelides. There may, however, be two major mutations causing ty-pos OCA with ephelides, one associated with D15S12 allele 1 and the other associated with D15S12 allele 2. The two loci, GABRA5 and D15S24, flanking D15S12, are both hypervariable, and many different haplotypes were observed with the alleles at the three loci on both ty-pos OCA-associated chromosomes and [open quotes]normal[close quotes] chromosomes. No haplotype showed statistically significant association with ty-pos OCA, and thus none could be used to predict the origins of the ty-pos OCA mutations. On the basis of the D15S12 results, there is evidence for multiple ty-pos OCA mutations in southern African negroids. 31 refs., 1 fig., 3 tabs.

  2. Validation of quantitative attenuation and backscattering coefficient measurements by optical coherence tomography in the concentration-dependent and multiple scattering regime

    NASA Astrophysics Data System (ADS)

    Almasian, Mitra; Bosschaart, Nienke; van Leeuwen, Ton G.; Faber, Dirk J.

    2015-12-01

    Optical coherence tomography (OCT) has the potential to quantitatively measure optical properties of tissue such as the attenuation coefficient and backscattering coefficient. However, to obtain reliable values for strong scattering tissues, accurate consideration of the effects of multiple scattering and the nonlinear relation between the scattering coefficient and scatterer concentration (concentration-dependent scattering) is required. We present a comprehensive model for the OCT signal in which we quantitatively account for both effects, as well as our system parameters (confocal point spread function and sensitivity roll-off). We verify our model with experimental data from controlled phantoms of monodisperse silica beads (scattering coefficients between 1 and 30 mm-1 and scattering anisotropy between 0.4 and 0.9). The optical properties of the phantoms are calculated using Mie theory combined with the Percus-Yevick structure factor to account for concentration-dependent scattering. We demonstrate excellent agreement between the OCT attenuation and backscattering coefficient predicted by our model and experimentally derived values. We conclude that this model enables us to accurately model OCT-derived parameters (i.e., attenuation and backscattering coefficients) in the concentration-dependent and multiple scattering regime for spherical monodisperse samples.

  3. Lymphocyte Subsets Show Different Response Patterns to In Vivo Bound Natalizumab—A Flow Cytometric Study on Patients with Multiple Sclerosis

    PubMed Central

    Einhaeupl, Max; Oppermann, Katrin; Hitzl, Wolfgang; Wipfler, Peter; Sellner, Johann; Golaszewski, Stefan; Afazel, Shahrzad; Haschke-Becher, Elisabeth; Trinka, Eugen; Kraus, Joerg

    2012-01-01

    Natalizumab is an effective monoclonal antibody therapy for the treatment of relapsing- remitting multiple sclerosis (RRMS) and interferes with immune cell migration into the central nervous system by blocking the α4 subunit of very-late activation antigen-4 (VLA-4). Although well tolerated and very effective, some patients still suffer from relapses in spite of natalizumab therapy or from unwanted side effects like progressive multifocal leukoencephalopathy (PML). In search of a routine-qualified biomarker on the effectiveness of natalizumab therapy we applied flow cytometry and analyzed natalizumab binding to α4 and α4 integrin surface levels on T-cells, B-cells, natural killer (NK) cells, and NKT cells from 26 RRMS patients under up to 72 weeks of therapy. Four-weekly infusions of natalizumab resulted in a significant and sustained increase of lymphocyte-bound natalizumab (p<0.001) which was paralleled by a significant decrease in detectability of the α4 integrin subunit on all lymphocyte subsets (p<0.001). We observed pronounced natalizumab accumulations on T and B cells at single measurements in all patients who reported clinical disease activity (n = 4). The natalizumab binding capacity of in vitro saturated lymphocytes collected during therapy was strongly diminished compared to treatment-naive cells indicating a therapy-induced reduction of α4. Summing up, this pilot study shows that flow cytometry is a useful method to monitor natalizumab binding to lymphocytes from RRMS patients under therapy. Investigating natalizumab binding provides an opportunity to evaluate the molecular level of effectiveness of natalizumab therapy in individual patients. In combination with natalizumab saturation experiments, it possibly even provides a means of studying the feasability of patient-tailored infusion intervals. A routine-qualified biomarker on the basis of individual natalizumab saturation on lymphocyte subsets might be an effective tool to improve treatment safety. PMID:22363732

  4. Multigrid-based reconstruction algorithm for quantitative photoacoustic tomography

    PubMed Central

    Li, Shengfu; Montcel, Bruno; Yuan, Zhen; Liu, Wanyu; Vray, Didier

    2015-01-01

    This paper proposes a multigrid inversion framework for quantitative photoacoustic tomography reconstruction. The forward model of optical fluence distribution and the inverse problem are solved at multiple resolutions. A fixed-point iteration scheme is formulated for each resolution and used as a cost function. The simulated and experimental results for quantitative photoacoustic tomography reconstruction show that the proposed multigrid inversion can dramatically reduce the required number of iterations for the optimization process without loss of reliability in the results. PMID:26203371

  5. [Relevance of Magnet Resonance Tomography in the Diagnosis and Assessment of Course of Disease in Patients with Multiple Sclerosis].

    PubMed

    Lukas, C; Sailer, M

    2015-09-01

    Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) with a substantial destructive axonal component that is responsible for the permanent disability accumulating during the course of the disease. Magnetic resonance imaging (MRI) has become the most important method in the diagnosis of MS. The high sensitivity of the MRI permits to detect focal and diffuse inflammatory disease involvement in vivo. In clinical routine the detection and quantification of focal pathology contributes substantially to an early diagnosis of MS. The detection of a substantial lesion load at the beginning of the disease increases the probability of an early conversion to clinically definite MS and the risk of accumulating disability in the first years of the disease. In 2001 this diagnostic and prognostic gain of information at an early stage of the disease resulted in a conceptual shift regarding diagnostic criteria. This concept comprises clinical and MRI criteria. The current 2010 revised criteria follow the concept of substituting a clinical relapse by subclinical MRI activity and allow the diagnosis of MS from one single MRI after the first relapse. This diagnostic approach using MRI allows an early treatment within an appropriate window of treatment opportunity. PMID:26421860

  6. 18F-fluoroethyl-L-tyrosine positron emission tomography for the differential diagnosis of tumefactive multiple sclerosis versus glioma: A case report

    PubMed Central

    KEBIR, SIED; GAERTNER, FLORIAN C.; MUELLER, MARCUS; NELLES, MICHAEL; SIMON, MATTHIAS; SCHÄFER, NIKLAS; STUPLICH, MORITZ; SCHAUB, CHRISTINA; NIESSEN, MICHAEL; MACK, FREDERIC; BUNDSCHUH, RALPH; GRESCHUS, SUSANNE; ESSLER, MARKUS; GLAS, MARTIN; HERRLINGER, ULRICH

    2016-01-01

    Large demyelinating inflammatory central nervous system (CNS) lesions may present with contrast enhancement on magnetic resonance imaging and may mimic CNS tumors such as glioma. In ambiguous cases, new diagnostic tools that may be helpful for distinguishing between demyelinating inflammatory and neoplastic CNS lesions are required. The current study presents the case of a patient with a large contrast-enhanced frontal brain lesion, who was initially diagnosed with tumefactive multiple sclerosis. Following the progression of the brain lesion, an 18F-fluoroethyl-L-tyrosine positron emission tomography (18F-FET PET) was performed, revealing markedly elevated static 18F-FET uptake parameters along with time activity-curves consistent with glioma. Subsequently, a biopsy was undertaken, which confirmed the presence of anaplastic oligoastrocytoma. This case illustrates that 18F-FET PET may provide useful diagnostic information in cases where distinction between neoplastic and demyelinating inflammatory CNS lesions is challenging. However, further systematic and prospective analyses are warranted to explore the value of this method in this setting. PMID:26998148

  7. Successful sinus restoration for transverse-sigmoid sinus dural arteriovenous fistula complicated by multiple venous sinus occlusions: The usefulness of preoperative computed tomography venography

    PubMed Central

    Takemoto, Koichiro; Higashi, Toshio; Sakamoto, Seisaburo; Inoue, Tooru

    2015-01-01

    Background: Although sinus restoration for transverse-sigmoid sinus (TSS) dural arteriovenous fistula (DAVF) has rarely been reported over the past decade, its advantage and indication still remain unclear. Herein, we discuss the indications and technical aspects of this therapy with a review of the literature. Case Description: A 79-year-old female was referred to our department with generalized convulsion. An angiogram revealed a DAVF at the junction of the right TSS. The right sigmoid and left transverse sinuses were occluded, which resulted in remarkable leptomeningeal venous reflux and cerebral venous congestion. A preoperative computed tomography (CT) venogram precisely revealed the occluded segment of the right sigmoid sinus, which facilitated the sinus restoration with balloon percutaneous transluminal angioplasty and stenting. Conclusion: Sinus restoration is preferable in patients with severe cerebral venous congestion due to multiple sinus occlusions and/or a restricted collateral venous outlet. CT venography is useful for precise evaluation of the length and configuration of the occluded segment, which thus make it possible to evaluate the feasibility of stenting. PMID:26392914

  8. Comparison of multifocal visual evoked potential, standard automated perimetry and optical coherence tomography in assessing visual pathway in multiple sclerosis patients

    PubMed Central

    Laron, Michal; Cheng, Han; Zhang, Bin; Schiffman, Jade S.; Tang, Rosa A.; Frishman, Laura J.

    2010-01-01

    Background Multifocal visual evoked potentials (mfVEP) measure local response amplitude and latency in the field of vision Objective To compare the sensitivity of mfVEP, Humphrey visual field (HVF) and optical coherence tomography (OCT) in detecting visual abnormality in multiple sclerosis (MS) patients. Methods MfVEP, HVF, and OCT (retinal nerve fiber layer [RNFL]) were performed in 47 MS-ON eyes (last optic neuritis (ON) attack ? 6 months prior) and 65 MS-no-ON eyes without ON history. Criteria to define an eye as abnormal were: mfVEP 1) amplitude/latency: either amplitude or latency probability plots meeting cluster criteria with 95% specificity 2) amplitude or latency alone (specificity: 97% and 98%, respectively); HVF and OCT, mean deviation and RNFL thickness meeting p < 0.05, respectively. Results MfVEP (amplitude/latency) identified more abnormality in MS-ON eyes (89%) than HVF (72%), OCT (62%), mfVEP amplitude (66%) or latency (67%) alone. 18% of MS-no-ON eyes were abnormal for both mfVEP (amplitude/latency) and HVF compared to 8% with OCT. Agreement between tests ranged from 60% to 79%. MfVEP (amplitude/latency) categorized an additional 15% of MS-ON eyes as abnormal compared to HVF and OCT combined. Conclusions MfVEP, which detects both demyelination (increased latency) and neural degeneration (reduced amplitude) revealed more abnormality than HVF or OCT in MS patients. PMID:20207786

  9. The meaning of interior tomography

    NASA Astrophysics Data System (ADS)

    Wang, Ge; Yu, Hengyong

    2013-08-01

    The classic imaging geometry for computed tomography is for the collection of un-truncated projections and the reconstruction of a global image, with the Fourier transform as the theoretical foundation that is intrinsically non-local. Recently, interior tomography research has led to theoretically exact relationships between localities in the projection and image spaces and practically promising reconstruction algorithms. Initially, interior tomography was developed for x-ray computed tomography. Then, it was elevated to have the status of a general imaging principle. Finally, a novel framework known as omni-tomography is being developed for a grand fusion of multiple imaging modalities, allowing tomographic synchrony of diversified features.

  10. "The Show"

    ERIC Educational Resources Information Center

    Gehring, John

    2004-01-01

    For the past 16 years, the blue-collar city of Huntington, West Virginia, has rolled out the red carpet to welcome young wrestlers and their families as old friends. They have come to town chasing the same dream for a spot in what many of them call "The Show". For three days, under the lights of an arena packed with 5,000 fans, the state's best

  11. Multiple mantle upwellings in the transition zone beneath the northern East-African Rift system from relative P-wave travel-time tomography

    NASA Astrophysics Data System (ADS)

    Civiero, Chiara; Hammond, James O. S.; Goes, Saskia; Fishwick, Stewart; Ahmed, Abdulhakim; Ayele, Atalay; Doubre, Cecile; Goitom, Berhe; Keir, Derek; Kendall, J.-Michael; Leroy, Sylvie; Ogubazghi, Ghebrebrhan; Rümpker, Georg; Stuart, Graham W.

    2015-09-01

    Mantle plumes and consequent plate extension have been invoked as the likely cause of East African Rift volcanism. However, the nature of mantle upwelling is debated, with proposed configurations ranging from a single broad plume connected to the large low-shear-velocity province beneath Southern Africa, the so-called African Superplume, to multiple lower-mantle sources along the rift. We present a new P-wave travel-time tomography model below the northern East-African, Red Sea, and Gulf of Aden rifts and surrounding areas. Data are from stations that span an area from Madagascar to Saudi Arabia. The aperture of the integrated data set allows us to image structures of ˜100 km length-scale down to depths of 700-800 km beneath the study region. Our images provide evidence of two clusters of low-velocity structures consisting of features with diameter of 100-200 km that extend through the transition zone, the first beneath Afar and a second just west of the Main Ethiopian Rift, a region with off-rift volcanism. Considering seismic sensitivity to temperature, we interpret these features as upwellings with excess temperatures of 100 ± 50 K. The scale of the upwellings is smaller than expected for lower mantle plume sources. This, together with the change in pattern of the low-velocity anomalies across the base of the transition zone, suggests that ponding or flow of deep-plume material below the transition zone may be spawning these upper mantle upwellings. This article was corrected on 28 SEP 2015. See the end of the full text for details.

  12. Assessment of Double Outlet Right Ventricle Associated with Multiple Malformations in Pediatric Patients Using Retrospective ECG-Gated Dual-Source Computed Tomography

    PubMed Central

    Shi, Ke; Chen, Jing; Zhang, Ge; Xu, Hua-yan

    2015-01-01

    Purpose To evaluate the feasibility and diagnostic accuracy of retrospective electrocardiographically (ECG)-gated dual-source computed tomography (DSCT) for the assessment of double outlet right ventricle (DORV) and associated multiple malformations in pediatric patients. Materials and Methods Forty-seven patients <10 years of age with DORV underwent retrospective ECG-gated DSCT. The location of the ventricular septal defect (VSD), alignment of the two great arteries, and associated malformations were assessed. The feasibility of retrospective ECG-gated DSCT in pediatric patients was assessed, the image quality of DSCT and the agreement of the diagnosis of associated malformations between DSCT and transthoracic echocardiography (TTE) were evaluated, the diagnostic accuracies of DSCT and TTE were referred to surgical results, and the effective doses were calculated. Results Apart from DORV, 109 associated malformations were confirmed postoperatively. There was excellent agreement (? = 0.90) for the diagnosis of associated malformations between DSCT and TTE. However, DSCT was superior to TTE in demonstrating paracardiac anomalies (sensitivity, coronary artery anomalies: 100% vs. 80.00%, anomalies of great vessels: 100% vs. 88.57%, separate thoracic and abdominal anomalies: 100% vs. 76.92%, respectively). Combined with TTE, DSCT can achieve excellent diagnostic performance in intracardiac anomalies (sensitivity, 91.30% vs. 100%). The mean image quality score was 3.70 0.46 (? = 0.76). The estimated mean effective dose was < 1 mSv (0.88 0.34 mSv). Conclusions Retrospective ECG-gated DSCT is a better diagnostic tool than TTE for pediatric patients with complex congenital heart disease such as DORV. Combined with TTE, it may reduce or even obviate the use of invasive cardiac catheterization, and thus expose the patients to a much lower radiation dose. PMID:26115034

  13. Attenuation-difference radar tomography: results of a multiple-plane experiment at the U.S. Geological Survey Fractured-Rock Research Site, Mirror Lake, New Hampshire

    USGS Publications Warehouse

    Lane, J.W., Jr.; Day-Lewis, F. D.; Harris, J.M.; Haeni, F.P.; Gorelick, S.M.

    2000-01-01

    Attenuation-difference, borehole-radar tomography was used to monitor a series of sodium chloride tracer injection tests conducted within the FSE, wellfield at the U.S. Geological Survey Fractured-Rock Hydrology Research Site in Grafton County, New Hampshire, USA. Borehole-radar tomography surveys were conducted using the sequential-scanning and injection method in three boreholes that form a triangular prism of adjoining tomographic image planes. Results indicate that time-lapse tomography methods provide high-resolution images of tracer distribution in permeable zones.

  14. Stripe sensor tomography.

    PubMed

    Barbic, Mladen; Vltava, Lvcian; Barrett, Christopher P; Emery, Teresa H; Scherer, Axel

    2008-03-01

    We introduce a general concept of tomographic imaging for the case of an imaging sensor that has a stripelike shape. We first show that there is no difference, in principle, between two-dimensional tomography using conventional electromagnetic or particle radiation and tomography where a stripe sensor is mechanically scanned over a sample at a sequence of different angles. For a single stripe detector imaging, linear motion and angular rotation are required. We experimentally demonstrate single stripe sensor imaging principle using an elongated inductive coil detector. By utilizing an array of parallel stripe sensors that can be individually addressed, two-dimensional imaging can be performed with rotation only, eliminating the requirement for linear motion, as we also experimentally demonstrate with parallel coil array. We conclude that imaging with a stripe-type sensor of particular width and thickness (where the width is much larger than the thickness) is resolution limited only by the thickness (smaller parameter) of the sensor. We give examples of multiple sensor families where this imaging technique may be beneficial such as magnetoresistive, inductive, superconducting quantum interference device, and Hall effect sensors, and, in particular, discuss the possibilities of the technique in the field of magnetic resonance imaging. PMID:18377013

  15. Novel human astrovirus strains showing multiple recombinations within highly conserved ORF1b detected from hospitalized acute watery diarrhea cases in Kolkata, India.

    PubMed

    Pativada, Madhusudhan; Bhattacharya, Rittwika; Krishnan, Triveni

    2013-12-01

    Human astroviruses (HAstVs) associated with acute watery diarrhea among hospitalized infants, children and adults as sole or mixed infection, were earlier reported from Kolkata, India. Further, novel recombinations have been detected through sequencing of the highly conserved ORF1b (RdRp) region of seven human astrovirus strains in Kolkata, India. Primers were designed and the ORF1b region was amplified by RT-PCR and sequenced. To examine the evolutionary pressures influencing the evolution of human astroviruses we implemented evolutionary genetics analysis. Maximum recombination break points detected in Kolkata strain IDH1300 were 8 and a single break point location was detected at 1205nt position. Partition-wise phylogenetic analyses of the IDH1300 Kolkata strain did not show close homology to the reference strains. Further phylogenetic analyses of full length ORF1b region of the seven human astrovirus strains showed that they formed a close cluster with each other and displayed a separate lineage in comparison to reference human astrovirus strains worldwide. This study shows the emergence of novel recombinant human astrovirus strains in Kolkata, India, warranting stringent surveillance to monitor the genetic diversity of human astrovirus strains infecting different age groups. PMID:24064378

  16. Microarray delineation of familial chromosomal imbalance with deletion 5q35 and duplication 10q25 in a child showing multiple anomalies and dysmorphism.

    PubMed

    Masri, Amira; Gimelli, Stefania; Hamamy, Hanan; Sloan-Bna, Frdrique

    2014-05-01

    We describe a 6-month-old female with developmental delay, hypotonia, supernumerary nipples, and distinct craniofacial features. Postnatal chromosome analysis revealed an unbalanced karyotype involving a der (5) and array-CGH defined two unbalanced regions with partial 2.3 Mb deletion of 5q35.3 in combination with a large 19.5 Mb duplication of chromosome 10 from q25.3 to q26.3. Parental karyotyping analysis showed that the father was carrier of a balanced t(5;10)(q35;q25). Two cousins of the proband with similar facial features had the same unbalanced karyotype with presence of the der (5) inherited from the malsegregation of the familial translocation. Additionally, three siblings (two deceased and one abortion) manifested a more severe phenotype including congenital heart defect, cleft palate, and agenesis of the corpus callosum and were diagnosed with unbalanced karyotypes inherited from the familial balanced translocation. PMID:24478242

  17. Cytokinin-deficient transgenic Arabidopsis plants show multiple developmental alterations indicating opposite functions of cytokinins in the regulation of shoot and root meristem activity.

    PubMed

    Werner, Toms; Motyka, Vclav; Laucou, Valrie; Smets, Rafal; Van Onckelen, Harry; Schmlling, Thomas

    2003-11-01

    Cytokinins are hormones that regulate cell division and development. As a result of a lack of specific mutants and biochemical tools, it has not been possible to study the consequences of cytokinin deficiency. Cytokinin-deficient plants are expected to yield information about processes in which cytokinins are limiting and that, therefore, they might regulate. We have engineered transgenic Arabidopsis plants that overexpress individually six different members of the cytokinin oxidase/dehydrogenase (AtCKX) gene family and have undertaken a detailed phenotypic analysis. Transgenic plants had increased cytokinin breakdown (30 to 45% of wild-type cytokinin content) and reduced expression of the cytokinin reporter gene ARR5:GUS (beta-glucuronidase). Cytokinin deficiency resulted in diminished activity of the vegetative and floral shoot apical meristems and leaf primordia, indicating an absolute requirement for the hormone. By contrast, cytokinins are negative regulators of root growth and lateral root formation. We show that the increased growth of the primary root is linked to an enhanced meristematic cell number, suggesting that cytokinins control the exit of cells from the root meristem. Different AtCKX-green fluorescent protein fusion proteins were localized to the vacuoles or the endoplasmic reticulum and possibly to the extracellular space, indicating that subcellular compartmentation plays an important role in cytokinin biology. Analyses of promoter:GUS fusion genes showed differential expression of AtCKX genes during plant development, the activity being confined predominantly to zones of active growth. Our results are consistent with the hypothesis that cytokinins have central, but opposite, regulatory functions in root and shoot meristems and indicate that a fine-tuned control of catabolism plays an important role in ensuring the proper regulation of cytokinin functions. PMID:14555694

  18. Cytokinin-Deficient Transgenic Arabidopsis Plants Show Multiple Developmental Alterations Indicating Opposite Functions of Cytokinins in the Regulation of Shoot and Root Meristem Activity

    PubMed Central

    Werner, Tom; Motyka, Vclav; Laucou, Valrie; Smets, Rafal; Van Onckelen, Harry; Schmlling, Thomas

    2003-01-01

    Cytokinins are hormones that regulate cell division and development. As a result of a lack of specific mutants and biochemical tools, it has not been possible to study the consequences of cytokinin deficiency. Cytokinin-deficient plants are expected to yield information about processes in which cytokinins are limiting and that, therefore, they might regulate. We have engineered transgenic Arabidopsis plants that overexpress individually six different members of the cytokinin oxidase/dehydrogenase (AtCKX) gene family and have undertaken a detailed phenotypic analysis. Transgenic plants had increased cytokinin breakdown (30 to 45% of wild-type cytokinin content) and reduced expression of the cytokinin reporter gene ARR5:GUS (?-glucuronidase). Cytokinin deficiency resulted in diminished activity of the vegetative and floral shoot apical meristems and leaf primordia, indicating an absolute requirement for the hormone. By contrast, cytokinins are negative regulators of root growth and lateral root formation. We show that the increased growth of the primary root is linked to an enhanced meristematic cell number, suggesting that cytokinins control the exit of cells from the root meristem. Different AtCKX-green fluorescent protein fusion proteins were localized to the vacuoles or the endoplasmic reticulum and possibly to the extracellular space, indicating that subcellular compartmentation plays an important role in cytokinin biology. Analyses of promoter:GUS fusion genes showed differential expression of AtCKX genes during plant development, the activity being confined predominantly to zones of active growth. Our results are consistent with the hypothesis that cytokinins have central, but opposite, regulatory functions in root and shoot meristems and indicate that a fine-tuned control of catabolism plays an important role in ensuring the proper regulation of cytokinin functions. PMID:14555694

  19. Patterns of landscape form in the upper Rhne basin, Central Swiss Alps, predominantly show lithologic controls despite multiple glaciations and variations in rock uplift rates

    NASA Astrophysics Data System (ADS)

    Stutenbecker, L. A.; Costa, A.; Schlunegger, F.

    2015-10-01

    The development of topography is mainly dependent on the interplay of uplift and erosion, which are in term controlled by various factors including climate, glaciers, lithology, seismic activity and short-term variables such as anthropogenic impact. While most studies have focused on the role of tectonics and climate on the landscape form and underlying processes, less attention has been paid on exploring the controls of lithology on erosion. The Central European Alps are characterized by a large spatial variability in exposed lithologies and as such offer an ideal laboratory to investigate the lithological controls on erosion and landscape form. Here, we focus on the ca. 5400 km2-large upper Rhne basin situated in the Central Swiss Alps to explore how the lithological architecture of the bedrock conditions the Alpine landscape. To this extent, we extract geomorphological parameters along the channels of ca. 50 tributary basins, whose catchments are located in either granitic basement rocks (External massifs), oceanic meta-sedimentary and ophiolitic rocks (Penninic nappes) or fine-grained continental-margin sediments (Helvetic nappes). The analysis of longitudinal river profiles show that all tributary rivers within the Rhne basin are in topographic transient state as testified by mainly convex or concave-convex longitudinal stream channel profiles with several knickpoints of either tectonic or glacial origin. In addition, although the entire Rhne basin shows a strong glacial inheritance (and is still partly glaciated) and some of the highest uplift rates recently measured in the Alps, the river network has responded differently to those perturbations as revealed by the morphometric data. In particular, tributary basins in the Helvetic nappes are the most equilibrated (concave river profiles, overall lower elevations, less steep slope gradients and lowest hypsometric integrals), while the tributaries located in the External massifs are least equilibrated, where streams yield strong convex long profiles, and where the tributary basins have the highest hypsometric integral and reveal the steepest hillslopes. We interpret this pattern to reflect differences in response times of the fluvial erosion in tributary streams towards glacial and tectonic perturbations, where the corresponding lengths strongly depend on the lithology and therefore on the bedrock erodibility.

  20. Mitochondrial phylogeny shows multiple independent ecological transitions and northern dispersion despite of Pleistocene glaciations in meadow and steppe vipers (Vipera ursinii and Vipera renardi).

    PubMed

    Zinenko, Oleksandr; Stümpel, Nikolaus; Mazanaeva, Lyudmila; Bakiev, Andrey; Shiryaev, Konstantin; Pavlov, Aleksey; Kotenko, Tatiana; Kukushkin, Oleg; Chikin, Yury; Duisebayeva, Tatiana; Nilson, Göran; Orlov, Nikolai L; Tuniyev, Sako; Ananjeva, Natalia B; Murphy, Robert W; Joger, Ulrich

    2015-03-01

    The phylogeny and historical demography of small Eurasian vipers of the Vipera ursinii and V. renardi complexes were studied using mitochondrial DNA sequences analysed with Bayesian inference, Maximum Likelihood and Maximum Parsimony approaches, and mismatch distributions. Diversification in the group resulted from an initial dispersion in the later Pliocene - Pleistocene in two directions: north-westwards via the Balkans (V. ursinii complex) and north-eastwards from Asia Minor via the Caucasus (V. renardi complex). An independent, comparatively recent transition occurred from montane habitats to lowland grasslands in different mitochondrial lineages during the Late Pleistocene, when representatives of the both complexes had reached lowland steppes to the north. Effective population size showed clear signs of rapid growth in eastern V. renardi, triggered by colonization of vast lowland steppes, but in western V. ursinii complex grew during the Last Glaciation and experienced stabilization in Holocene. Expansion and population growth in lowland lineages of V. renardi was not strongly affected by Pleistocene climatic oscillations, when cold, dry conditions could have favoured species living in open grasslands. The high diversity of closely related haplotypes in the Caucasus and Tien-Shan could have resulted from repetitive expansion-constriction-isolation events in montane regions during Pleistocene climate fluctuations. The mitochondrial phylogeny pattern conflicts with the current taxonomy. PMID:25527984

  1. A Multiple siRNA-Based Anti-HIV/SHIV Microbicide Shows Protection in Both In Vitro and In Vivo Models

    PubMed Central

    Raulji, Payal; Mohapatra, Subhra; Mohapatra, Shyam S

    2015-01-01

    Human immunodeficiency virus (HIV) types 1 and 2 (HIV-1 and HIV-2) are the etiologic agents of AIDS. Most HIV-1 infected individuals worldwide are women, who acquire HIV infections during sexual contact. Blocking HIV mucosal transmission and local spread in the female lower genital tract is important in preventing infection and ultimately eliminating the pandemic. Microbicides work by destroying the microbes or preventing them from establishing an infection. Thus, a number of different types of microbicides are under investigation, however, the lack of their solubility and bioavailability, and toxicity has been major hurdles. Herein, we report the development of multifunctional chitosan-lipid nanocomplexes that can effectively deliver plasmids encoding siRNA(s) as microbicides without adverse effects and provide significant protection against HIV in both in vitro and in vivo models. Chitosan or chitosan-lipid (chlipid) was complexed with a cocktail of plasmids encoding HIV-1-specific siRNAs (psiRNAs) and evaluated for their efficacy in HEK-293 cells, PBMCs derived from nonhuman primates, 3-dimensional human vaginal ectocervical tissue (3D-VEC) model and also in non-human primate model. Moreover, prophylactic administration of the chlipid to deliver a psiRNA cocktail intravaginally with a cream formulation in a non-human primate model showed substantial reduction of SHIV (simian/human immunodeficiency virus SF162) viral titers. Taken together, these studies demonstrate the potential of chlipid-siRNA nanocomplexes as a potential genetic microbicide against HIV infections. PMID:26407080

  2. The DNA of a Plant Retroviroid-Like Element Is Fused to Different Sites in the Genome of a Plant Pararetrovirus and Shows Multiple Forms with Sequence Deletions

    PubMed Central

    Vera, Antonio; Dars, Jos-Antonio; Flores, Ricardo; Hernndez, Carmen

    2000-01-01

    Carnation small viroid-like RNA (CarSV RNA) and its homologous DNA are the two forms of a unique plant retroviroid-like system. CarSV RNA is a 275-nucleotide noninfectious viroid-like RNA, present in certain carnation plants, which can adopt hammerhead structures in both polarity strands and self-cleave accordingly. CarSV DNA is organized as a series of head-to-tail multimers forming part of extrachromosomal elements in which CarSV DNA sequences are fused to sequences of carnation etched ring virus (CERV), a plant pararetrovirus. Analysis of more than 30 CarSV-CERV DNA junctions showed that distinct regions of the viral genome seem able to interact with CarSV DNA. All these junctions were short nucleotide stretches common to both CarSV and CERV DNAs. This suggests a polymerase-driven mechanism for their origin involving an enzyme with low processivity, most likely the viral reverse transcriptase. This view was further supported by the observation that most of CarSV sequences forming part of the junctions correspond either to strong secondary structure motifs in the conformation proposed for CarSV RNA or to its self-cleavage sites, which may have facilitated polymerase jumping. Accompanying the most-abundant CarSV RNA, a series of CarSV RNAs with sequence deletions were previously characterized. Here we have identified some of their corresponding DNA forms, together with other CarSV DNA forms with deletions not found in any CarSV RNA species identified so far. Some of these CarSV DNA forms have also been detected fused to CERV sequences. The existence of these shortened CarSV DNA versions may provide a continuous input of their corresponding transcripts and explain the persistence of CarSV RNAs with defective hammerhead structures for which an RNA-RNA model of amplification seems unlikely. PMID:11044083

  3. Ray tracing of multiple transmitted/reflected/converted waves in 2-D/3-D layered anisotropic TTI media and application to crosswell traveltime tomography

    NASA Astrophysics Data System (ADS)

    Bai, Chao-Ying; Huang, Guo-Jiao; Li, Xiao-Ling; Zhou, Bing; Greenhalgh, Stewart

    2013-11-01

    To overcome the deficiency of some current grid-/cell-based ray tracing algorithms, which are only able to handle first arrivals or primary reflections (or conversions) in anisotropic media, we have extended the functionality of the multistage irregular shortest-path method to 2-D/3-D tilted transversely isotropic (TTI) media. The new approach is able to track multiple transmitted/reflected/converted arrivals composed of any kind of combinations of transmissions, reflections and mode conversions. The basic principle is that the seven parameters (five elastic parameters plus two polar angles defining the tilt of the symmetry axis) of the TTI media are sampled at primary nodes, and the group velocity values at secondary nodes are obtained by tri-linear interpolation of the primary nodes across each cell, from which the group velocities of the three wave modes (qP, qSV and qSH) are calculated. Finally, we conduct grid-/cell-based wave front expansion to trace multiple transmitted/reflected/converted arrivals from one region to the next. The results of calculations in uniform anisotropic media indicate that the numerical results agree with the analytical solutions except in directions of SV-wave triplications, at which only the lowest velocity value is selected at the singularity points by the multistage irregular shortest-path anisotropic ray tracing method. This verifies the accuracy of the methodology. Several simulation results show that the new method is able to efficiently and accurately approximate situations involving continuous velocity variations and undulating discontinuities, and that it is suitable for any combination of multiple transmitted/reflected/converted arrival tracking in TTI media of arbitrary strength and tilt. Crosshole synthetic traveltime tomographic tests have been performed, which highlight the importance of using such code when the medium is distinctly anisotropic.

  4. Computed tomography of infantile hepatic hemangioendothelioma.

    PubMed

    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, multinodular 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. PMID:3872044

  5. Toward real-time bent-ray breast ultrasound tomography using GPUs

    NASA Astrophysics Data System (ADS)

    Labyed, Yassin; Huang, Lianjie

    2014-03-01

    Breast ultrasound tomography is a promising imaging modality that has the potential to improve the diagnosis and screening of breast cancer. We develop a bent-ray ultrasound tomography algorithm to reconstruct sound-speed images of the breast. We investigate the acceleration of the algorithm using graphical processing units (GPUs). We adapt the algorithmic steps of ultrasound bent-ray tomography to a GPU cluster, and use multi-GPU scaling to speed up the computation. Our results show that it is very promising to use a GPU cluster with multiple GPU cards to achieve nearly real-time tomographic reconstruction.

  6. Experimental Demonstration of Spectral Intensity Optical Coherence Tomography.

    PubMed

    Ryczkowski, Piotr; Turunen, Jari; Friberg, Ari T; Genty, Gory

    2016-01-01

    We demonstrate experimentally spectral-domain intensity optical coherence tomography using a Mach-Zehnder interferometer with balanced detection. We show that the technique allows for a point spread function with reduced full-width at half maximum compared to conventional optical coherence tomography. The method further provides benefits similar to those of chirped-pulse interferometry in terms of dispersion cancellation but only requires a broadband incoherent source and standard detectors. The measurements are in excellent agreement with the theoretical predictions. Finally, we propose an approach that enables the elimination of potential artefacts arising from multiple interfaces. PMID:26916668

  7. Experimental Demonstration of Spectral Intensity Optical Coherence Tomography

    PubMed Central

    Ryczkowski, Piotr; Turunen, Jari; Friberg, Ari T.; Genty, Goëry

    2016-01-01

    We demonstrate experimentally spectral-domain intensity optical coherence tomography using a Mach-Zehnder interferometer with balanced detection. We show that the technique allows for a point spread function with reduced full-width at half maximum compared to conventional optical coherence tomography. The method further provides benefits similar to those of chirped-pulse interferometry in terms of dispersion cancellation but only requires a broadband incoherent source and standard detectors. The measurements are in excellent agreement with the theoretical predictions. Finally, we propose an approach that enables the elimination of potential artefacts arising from multiple interfaces. PMID:26916668

  8. Experimental Demonstration of Spectral Intensity Optical Coherence Tomography

    NASA Astrophysics Data System (ADS)

    Ryczkowski, Piotr; Turunen, Jari; Friberg, Ari T.; Genty, Goëry

    2016-02-01

    We demonstrate experimentally spectral-domain intensity optical coherence tomography using a Mach-Zehnder interferometer with balanced detection. We show that the technique allows for a point spread function with reduced full-width at half maximum compared to conventional optical coherence tomography. The method further provides benefits similar to those of chirped-pulse interferometry in terms of dispersion cancellation but only requires a broadband incoherent source and standard detectors. The measurements are in excellent agreement with the theoretical predictions. Finally, we propose an approach that enables the elimination of potential artefacts arising from multiple interfaces.

  9. Solution of the inverse problem of magnetic induction tomography (MIT) with multiple objects: analysis of detectability and statistical properties with respect to the reconstructed conducting region.

    PubMed

    Merwa, Robert; Brunner, Patricia; Missner, Andreas; Hollaus, Karl; Scharfetter, Hermann

    2006-05-01

    Magnetic induction tomography (MIT) is a technique to image the passive electrical properties (i.e. conductivity, permittivity, permeability) of biological tissues. The inverse eddy current problem is nonlinear and ill-posed, thus a Gauss-Newton one-step method in combination with four different regularization schemes is used to obtain stable solutions. Simulations with 16 excitation coils, 32 receiving coils and different spherical perturbations inside a homogeneous cylinder were computed. In order to compare the statistical properties of the reconstructed results a Monte Carlo study with a SNR of 40 dB and 20 dB was carried out. Simulated conductivity perturbations inside a homogeneous cylinder can be localized and resolved and the results prove the feasibility of difference imaging with MIT. PMID:16636415

  10. Postmortem whole-body computed tomography angiography visualizing vascular rupture in a case of fatal car crash.

    PubMed

    Flach, Patricia M; Ross, Steffen G; Bolliger, Stephan A; Preiss, Ulrich S; Thali, Michael J; Spendlove, Danny

    2010-01-01

    In addition to the increasingly significant role of multislice computed tomography in forensic pathology, the performance of whole-body computed tomography angiography provides outstanding results. In this case, we were able to detect multiple injuries of the parenchymal organs in the upper abdomen as well as lesions of the brain parenchyma and vasculature of the neck. The radiologic findings showed complete concordance with the autopsy and even supplemented the autopsy findings in areas that are difficult to access via a manual dissection (such as the vasculature of the neck). This case shows how minimally invasive computed tomography angiography can serve as an invaluable adjunct to the classic autopsy procedure. PMID:20073614

  11. Noise reduction in muon tomography for detecting high density objects

    NASA Astrophysics Data System (ADS)

    Benettoni, M.; Bettella, G.; Bonomi, G.; Calvagno, G.; Calvini, P.; Checchia, P.; Cortelazzo, G.; Cossutta, L.; Donzella, A.; Furlan, M.; Gonella, F.; Pegoraro, M.; Rigoni Garola, A.; Ronchese, P.; Squarcia, S.; Subieta, M.; Vanini, S.; Viesti, G.; Zanuttigh, P.; Zenoni, A.; Zumerle, G.

    2013-12-01

    The muon tomography technique, based on multiple Coulomb scattering of cosmic ray muons, has been proposed as a tool to detect the presence of high density objects inside closed volumes. In this paper a new and innovative method is presented to handle the density fluctuations (noise) of reconstructed images, a well known problem of this technique. The effectiveness of our method is evaluated using experimental data obtained with a muon tomography prototype located at the Legnaro National Laboratories (LNL) of the Istituto Nazionale di Fisica Nucleare (INFN). The results reported in this paper, obtained with real cosmic ray data, show that with appropriate image filtering and muon momentum classification, the muon tomography technique can detect high density materials, such as lead, albeit surrounded by light or medium density material, in short times. A comparison with algorithms published in literature is also presented.

  12. Pseudolocal tomography

    DOEpatents

    Katsevich, A.J.; Ramm, A.G.

    1996-07-23

    Local tomographic data is used to determine the location and value of a discontinuity between a first internal density of an object and a second density of a region within the object. A beam of radiation is directed in a predetermined pattern through the region of the object containing the discontinuity. Relative attenuation data of the beam is determined within the predetermined pattern having a first data component that includes attenuation data through the region. The relative attenuation data is input to a pseudo-local tomography function, where the difference between the internal density and the pseudo-local tomography function is computed across the discontinuity. The pseudo-local tomography function outputs the location of the discontinuity and the difference in density between the first density and the second density. 7 figs.

  13. Cellular tomography.

    PubMed

    Hoenger, Andreas; Bouchet-Marquis, Cdric

    2011-01-01

    Traditionally, cellular specimens and tissues have been prepared for electron microscopy by chemical fixation or rapid freezing followed by freeze substitution and plastic embedding. Once embedded in a solid polymer, sections are obtained by room-temperature microtomy. More recently, two developments added a new twist to cellular electron microscopy: first, the rediscovery of tomographic 3-D reconstruction methods, which do not depend on any type of averaging procedures and hence are well suited for large irregular structures such as cellular organelles and large-macromolecular assemblies. Second, new advances made for the preparation of sectioned vitrified cellular specimens enable imaging them not only after plastic embedding but also directly in their vitrified state, recorded under strict cryo- and low-dose conditions. Today, tomography strongly benefits from an ever-evolving computer environment that now allows handling very large datasets with reasonable speed. Cellular tomography can be divided into four different classes: (A) tomography on thick (~300 nm) sections prepared from plastic embedded chemically fixed or freeze-substituted cells and tissues. (B) Large-scale tomographic 3-D data of entire cells obtained by serial sectioning of plastic embedded chemically fixed or freeze-substituted specimens obtained by computationally merging tomographic data from many consecutive sections within the grid plane and also in Z-direction. (C) Cryo-electron microscopy (cryo-EM) techniques now allow recording tomograms of intact vitrified small cells (e.g., bacteria) without substitution or sectioning. (D) Cryo-EM and cryo-tomography are increasingly applied to thin vitrified (<100 nm) obtained under strict cryo-conditions, including the during data recording in the microscope. Without extending to molecular tomography, which is described elsewhere in this book, this chapter leads the reader through cellular tomography by following the specifications outlined above. PMID:21501819

  14. Real-time processing for full-range Fourier-domain optical-coherence tomography with zero-filling interpolation using multiple graphic processing units.

    PubMed

    Watanabe, Yuuki; Maeno, Seiya; Aoshima, Kenji; Hasegawa, Haruyuki; Koseki, Hitoshi

    2010-09-01

    The real-time display of full-range, 2048?axial pixelx1024?lateral pixel, Fourier-domain optical-coherence tomography (FD-OCT) images is demonstrated. The required speed was achieved by using dual graphic processing units (GPUs) with many stream processors to realize highly parallel processing. We used a zero-filling technique, including a forward Fourier transform, a zero padding to increase the axial data-array size to 8192, an inverse-Fourier transform back to the spectral domain, a linear interpolation from wavelength to wavenumber, a lateral Hilbert transform to obtain the complex spectrum, a Fourier transform to obtain the axial profiles, and a log scaling. The data-transfer time of the frame grabber was 15.73?ms, and the processing time, which includes the data transfer between the GPU memory and the host computer, was 14.75?ms, for a total time shorter than the 36.70?ms frame-interval time using a line-scan CCD camera operated at 27.9?kHz. That is, our OCT system achieved a processed-image display rate of 27.23 frames/s. PMID:20820218

  15. Seismic Tomography.

    ERIC Educational Resources Information Center

    Anderson, Don L.; Dziewonski, Adam M.

    1984-01-01

    Describes how seismic tomography is used to analyze the waves produced by earthquakes. The information obtained from the procedure can then be used to map the earth's mantle in three dimensions. The resulting maps are then studied to determine such information as the convective flow that propels the crustal plates. (JN)

  16. Inferring Positions of Tumor and Nodes in Stage III Lung Cancer From Multiple Anatomical Surrogates Using Four-Dimensional Computed Tomography

    SciTech Connect

    Malinowski, Kathleen T.; Pantarotto, Jason R.; Senan, Suresh

    2010-08-01

    Purpose: To investigate the feasibility of modeling Stage III lung cancer tumor and node positions from anatomical surrogates. Methods and Materials: To localize their centroids, the primary tumor and lymph nodes from 16 Stage III lung cancer patients were contoured in 10 equal-phase planning four-dimensional (4D) computed tomography (CT) image sets. The centroids of anatomical respiratory surrogates (carina, xyphoid, nipples, mid-sternum) in each image set were also localized. The correlations between target and surrogate positions were determined, and ordinary least-squares (OLS) and partial least-squares (PLS) regression models based on a subset of respiratory phases (three to eight randomly selected) were created to predict the target positions in the remaining images. The three-phase image sets that provided the best predictive information were used to create models based on either the carina alone or all surrogates. Results: The surrogate most correlated with target motion varied widely. Depending on the number of phases used to build the models, mean OLS and PLS errors were 1.0 to 1.4 mm and 0.8 to 1.0 mm, respectively. Models trained on the 0%, 40%, and 80% respiration phases had mean ({+-} standard deviation) PLS errors of 0.8 {+-} 0.5 mm and 1.1 {+-} 1.1 mm for models based on all surrogates and carina alone, respectively. For target coordinates with motion >5 mm, the mean three-phase PLS error based on all surrogates was 1.1 mm. Conclusions: Our results establish the feasibility of inferring primary tumor and nodal motion from anatomical surrogates in 4D CT scans of Stage III lung cancer. Using inferential modeling to decrease the processing time of 4D CT scans may facilitate incorporation of patient-specific treatment margins.

  17. Solar Tomography

    NASA Astrophysics Data System (ADS)

    Davila, J. M.

    1993-12-01

    Images obtained by observing the solar corona from a single spacecraft typically measure the line-of-sight integral of the volumetric emissivity through the source. The resulting two-dimensional observations have an unavoidable ambiguity along the line of sight that can be removed only by making assumptions about the three dimensional nature of the emission. These ambiguities can be removed by observing the Sun from different vantage points, at the same time, i.e. solar tomography. The basic concept of tomographic is fairly simple. For an optically thin emission source, like the solar corona, each pixel in an image represents the line of sight integration of the volumetric emissivity of the plasma at the wavelength of observation. By obtaining several of these observations, from various angles, the underlying three dimensional structure of the emission can be deduced. This principle has been used extensively in the Medical community for the imaging of internal structure of the body with such techniques as Computer Aided Tomography (CAT) scanners and Magnetic Resonance Imaging (MRI). The purpose of this paper is to take an intial look at the following two questions: (1) Is tomography feasible with a few spacecraft?; and (2) What scientific objectives can be addressed?

  18. Considering sources and detectors distributions for quantitative photoacoustic tomography

    PubMed Central

    Song, Ningning; Deumié, Carole; Da Silva, Anabela

    2014-01-01

    Photoacoustic tomography (PAT) is a hybrid imaging modality that takes advantage of high optical contrast brought by optical imaging and high spatial resolution brought by ultrasound imaging. However, the quantification in photoacoustic imaging is challenging. Multiple optical illumination approach has proven to achieve uncoupling of diffusion and absorption effects. In this paper, this protocol is adopted and synthetic photoacoustic data, blurred with some noise, were generated. The influence of the distribution of optical sources and transducers on the reconstruction of the absorption and diffusion coefficients maps is studied. Specific situations with limited view angles were examined. The results show multiple illuminations with a wide field improve the reconstructions. PMID:25426322

  19. Detection of multiple myeloma by PET/CT in a patient with colon cancer.

    PubMed

    Chang, Chih-Yung; Peng, Yi-Jen; Shen, Daniel H W; Huang, Wen-Sheng; Cherng, Shiou-Chi

    2008-05-01

    A 76-year-old man with previous sigmoid colon resection for adenocarcinoma had low back pain for 2 months. Whole-body bone scintigraphy showed multiple focal Tc-99m methylene diphosphonate (MDP)-avid lesions in both rib cages and 3 lumbar vertebrae, indicating metastases. F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) imaging was performed for further evaluation of this possible metastatic disease and demonstrated the lumbar and costal metastases and several hypermetabolic areas in the pelvic bones, multiple thoracic vertebrae, both shoulders, and the right femur. Histopathologic examination of the right-sided iliac crest, however, revealed multiple myeloma. PMID:18431161

  20. Radial reflection diffraction tomography

    NASA Astrophysics Data System (ADS)

    Lehman, Sean K.; Norton, Stephen J.

    2004-10-01

    A wave-based tomographic imaging algorithm based upon a single rotating radially outward oriented transducer is developed. At successive angular locations at a fixed radius, the transducer launches a primary field and collects the backscattered field in a ``pitch/catch'' operation. The hardware configuration, operating mode, and data collection method are identical to that of most medical intravascular ultrasound (IVUS) systems. IVUS systems form images of the medium surrounding the probe based upon ultrasonic B scans, using a straight-ray model of sound propagation. The goal of this research is to develop a wave-based imaging algorithm using diffraction tomography techniques. Given the hardware configuration and the imaging method, this system is referred to as ``radial reflection diffraction tomography.'' Two hardware configurations are considered: a multimonostatic mode using a single transducer as described above, and a multistatic mode consisting of a single transmitter and an aperture formed by multiple receivers. In this latter case, the entire source/receiver aperture rotates about the fixed radius. Practically, such a probe is mounted at the end of a catheter or snaking tube that can be inserted into a part or medium with the goal of forming images of the plane perpendicular to the axis of rotation. An analytic expression for the multimonostatic inverse is derived, but ultimately the new Hilbert space inverse wave (HSIW) algorithm is used to construct images using both operating modes. Applications include improved IVUS imaging, bore hole tomography, and nondestructive evaluation (NDE) of parts with existing access holes. .

  1. High-Grade Glioma Radiation Therapy Target Volumes and Patterns of Failure Obtained From Magnetic Resonance Imaging and {sup 18}F-FDOPA Positron Emission Tomography Delineations From Multiple Observers

    SciTech Connect

    Kosztyla, Robert; Chan, Elisa K.; Hsu, Fred; Wilson, Don; Ma, Roy; Cheung, Arthur; Zhang, Susan; Moiseenko, Vitali; Benard, Francois; Nichol, Alan

    2013-12-01

    Purpose: The objective of this study was to compare recurrent tumor locations after radiation therapy with pretreatment delineations of high-grade gliomas from magnetic resonance imaging (MRI) and 3,4-dihydroxy-6-[{sup 18}F]fluoro-L-phenylalanine ({sup 18}F-FDOPA) positron emission tomography (PET) using contours delineated by multiple observers. Methods and Materials: Nineteen patients with newly diagnosed high-grade gliomas underwent computed tomography (CT), gadolinium contrast-enhanced MRI, and {sup 18}F-FDOPA PET/CT. The image sets (CT, MRI, and PET/CT) were registered, and 5 observers contoured gross tumor volumes (GTVs) using MRI and PET. Consensus contours were obtained by simultaneous truth and performance level estimation (STAPLE). Interobserver variability was quantified by the percentage of volume overlap. Recurrent tumor locations after radiation therapy were contoured by each observer using CT or MRI. Consensus recurrence contours were obtained with STAPLE. Results: The mean interobserver volume overlap for PET GTVs (42% ± 22%) and MRI GTVs (41% ± 22%) was not significantly different (P=.67). The mean consensus volume was significantly larger for PET GTVs (58.6 ± 52.4 cm{sup 3}) than for MRI GTVs (30.8 ± 26.0 cm{sup 3}, P=.003). More than 95% of the consensus recurrence volume was within the 95% isodose surface for 11 of 12 (92%) cases with recurrent tumor imaging. Ten (91%) of these cases extended beyond the PET GTV, and 9 (82%) were contained within a 2-cm margin on the MRI GTV. One recurrence (8%) was located outside the 95% isodose surface. Conclusions: High-grade glioma contours obtained with {sup 18}F-FDOPA PET had similar interobserver agreement to volumes obtained with MRI. Although PET-based consensus target volumes were larger than MRI-based volumes, treatment planning using PET-based volumes may not have yielded better treatment outcomes, given that all but 1 recurrence extended beyond the PET GTV and most were contained by a 2-cm margin on the MRI GTV.

  2. 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.

  3. Quantum gate-set tomography

    NASA Astrophysics Data System (ADS)

    Blume-Kohout, Robin

    2014-03-01

    Quantum information technology is built on (1) physical qubits and (2) precise, accurate quantum logic gates that transform their states. Developing quantum logic gates requires good characterization - both in the development phase, where we need to identify a device's flaws so as to fix them, and in the production phase, where we need to make sure that the device works within specs and predict residual error rates and types. This task falls to quantum state and process tomography. But until recently, protocols for tomography relied on a pre-existing and perfectly calibrated reference frame comprising the measurements (and, for process tomography, input states) used to characterize the device. In practice, these measurements are neither independent nor perfectly known - they are usually implemented via exactly the same gates that we are trying to characterize! In the past year, several partial solutions to this self-consistency problem have been proposed. I will present a framework (gate set tomography, or GST) that addresses and resolves this problem, by self-consistently characterizing an entire set of quantum logic gates on a black-box quantum device. In particular, it contains an explicit closed-form protocol for linear-inversion gate set tomography (LGST), which is immune to both calibration error and technical pathologies like local maxima of the likelihood (which plagued earlier methods). GST also demonstrates significant (multiple orders of magnitude) improvements in efficiency over standard tomography by using data derived from long sequences of gates (much like randomized benchmarking). GST has now been applied to qubit devices in multiple technologies. I will present and discuss results of GST experiments in technologies including a single trapped-ion qubit and a silicon quantum dot qubit. Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL850.

  4. Imaging of the Rotator Cuff With Optical Coherence Tomography.

    PubMed

    Hartshorn, Timothy; Ren, Jian; Vangsness, C Thomas

    2015-09-01

    This study evaluated the utility of optical coherence tomography (OCT) in imaging porcine and human rotator cuff (RTC) tissue, analyzed its effectiveness in identifying clinical pathology, and correlated these findings with histologic examination. Twelve human cadaveric and 6 porcine shoulders were evaluated. Six-millimeter-wide bone sections were harvested from the proximal humerus of each specimen, with each containing the entire enthesis of the respective RTC tendon, as well as 2 cm of tendon medial to the enthesis. Only the supraspinatus tendon was evaluated in the human specimens, whereas the enthesis of multiple RTC tendons were evaluated in the porcine model. All specimens were imaged using OCT and correlated with histologic evaluation. Optical coherence tomography evaluation of macroscopically healthy tissue consistently showed an easily identifiable banding pattern (birefringence) in contrast to a disorganized, homogeneous appearance in grossly diseased tissue. Optical coherence tomography was more effective for qualitative evaluation of RTC tissue, identification of bursal-sided RTC tears, and localization of calcific deposits, whereas intrasubstance tendon delaminations and partial articular-sided tendon avulsion lesions were relatively more difficult to identify. Optical coherence tomography correlated well with histologic evaluation in all specimens. Optical coherence tomography provides high-resolution, subsurface imaging of rotator cuff tissue in real-time to a depth of up to 4 mm with excellent correlation to histology in a cadaveric model. Optical coherence tomography could be an effective adjunctive tool for the identification and localization of rotator cuff pathology. The use of OCT in arthroscopic shoulder surgery potentially provides a minimally invasive modality for qualitative assessment of rotator cuff pathology. This may allow for a decrease in soft tissue dissection, improved qualitative assessment of cuff tissue, and improved patient outcomes. PMID:26375544

  5. Reduced retinal nerve fiber layer and macular thickness in patients with multiple sclerosis with no history of optic neuritis identified by the use of spectral domain high-definition optical coherence tomography.

    PubMed

    Fjeldstad, Cecilie; Bemben, Michael; Pardo, Gabriel

    2011-11-01

    Multiple sclerosis (MS) is a chronic immune-mediated disease of the central nervous system (CNS), with both inflammatory and degenerative components. The visual system is frequently involved, often in the form of visual loss from optic neuritis (ON). Retinal nerve fiber layer (RNFL) loss has been demonstrated in individuals with MS, not only in those with previous ON but also in absence of historical evidence of previous acute inflammation/demyelination of the optic nerve. Peripapillary RNFL measurements of all quadrants, central macular thickness, and average macular thickness were performed in 32 eyes of healthy volunteers and 60 eyes of individuals with a diagnosis of relapsing remitting MS using high definition spectral domain optical coherence tomography (HD-OCT). Both the Macular Cube 512 128 scan and RNFL measurement by the Optic Disc Cube 200 200 protocol were performed on all eyes. Eyes of individuals with MS with no previous ON had significantly decreased overall RNFL thickness (89.1 ?m) compared to controls (98.0 ?m) (p < 0.05). MS mainly affected the temporal quadrant (56.6 ?m versus [vs.] 67.8 ?m) (p < 0.05), and inferior quadrant (117.9 ?m vs. 132.1 ?m) (p < 0.05), respectively. Also, the patients with MS demonstrated significantly decreased average macular thickness (280 ?m) compared to the control group (287 ?m) (p < 0.05). A significant correlation between RNFL and average macular thickness was also found in eyes of patients with MS (r = 0.69, p < 0.01). HD-OCT is a quick, inexpensive and promising tool to detect subclinical changes in RNFL and macular thickness in individuals with MS. Longitudinal studies should be encouraged to examine disease progression over time in individuals with MS. PMID:21917458

  6. A multi-phase level set framework for source reconstruction in bioluminescence tomography

    SciTech Connect

    Huang Heyu; Qu Xiaochao; Liang Jimin; He Xiaowei; Chen Xueli; Yang Da'an; Tian Jie

    2010-07-01

    We propose a novel multi-phase level set algorithm for solving the inverse problem of bioluminescence tomography. The distribution of unknown interior source is considered as piecewise constant and represented by using multiple level set functions. The localization of interior bioluminescence source is implemented by tracing the evolution of level set function. An alternate search scheme is incorporated to ensure the global optimal of reconstruction. Both numerical and physical experiments are performed to evaluate the developed level set reconstruction method. Reconstruction results show that the proposed method can stably resolve the interior source of bioluminescence tomography.

  7. Random matrix-based dimensionality reduction for bioluminescence tomography reconstruction

    NASA Astrophysics Data System (ADS)

    Styles, Iain B.; Basevi, Hector R. A.; Guggenheim, James A.; Dehghani, Hamid

    2013-06-01

    We show how a random matrix can be used to reduce the dimensionality of the bioluminescence tomography reconstruction problem. A randomised low-rank approximation for the sensitivity matrix is computed, and we show how this can be used to reconstruct the bioluminescence source distribution on a randomised basis for the mesh nodes. The distribution on the original mesh can be found easily via a simple matrix multiplication. The majority of the computation required can be performed in advance of the reconstruction, and the reconstruction time itself is of the order milliseconds. This could allow for high frame rate real-time reconstructions to be performed.

  8. Proton computed tomography from multiple physics processes

    NASA Astrophysics Data System (ADS)

    Bopp, C.; Colin, J.; Cussol, D.; Finck, Ch; Labalme, M.; Rousseau, M.; Brasse, D.

    2013-10-01

    Proton CT (pCT) nowadays aims at improving hadron therapy treatment planning by mapping the relative stopping power (RSP) of materials with respect to water. The RSP depends mainly on the electron density of the materials. The main information used is the energy of the protons. However, during a pCT acquisition, the spatial and angular deviation of each particle is recorded and the information about its transmission is implicitly available. The potential use of those observables in order to get information about the materials is being investigated. Monte Carlo simulations of protons sent into homogeneous materials were performed, and the influence of the chemical composition on the outputs was studied. A pCT acquisition of a head phantom scan was simulated. Brain lesions with the same electron density but different concentrations of oxygen were used to evaluate the different observables. Tomographic images from the different physics processes were reconstructed using a filtered back-projection algorithm. Preliminary results indicate that information is present in the reconstructed images of transmission and angular deviation that may help differentiate tissues. However, the statistical uncertainty on these observables generates further challenge in order to obtain an optimal reconstruction and extract the most pertinent information.

  9. Photoacoustic Tomography

    NASA Astrophysics Data System (ADS)

    Wang, Lihong V.

    Photoacoustic tomography (PAT) refers to imaging that is based on the photoacoustic effect. Although the photoacoustic effect as a physical phenomenon was first reported on by Alexander Graham Bell in 1880 [1], PAT as an imaging technology was developed only after the advent of ultrasonic transducers, computers, and lasers [2-31]. A review on biomedical photoacoustics is available [32]. The motivation for PAT is to combine optical-absorption contrast with ultrasonic spatial resolution for deep imaging in the optical quasi-diffusive or diffusive regime. In PAT, the tissue is irradiated by usually a short-pulsed laser beam to achieve a thermal and acoustic impulse response (Fig. 19.1). Locally absorbed light is converted into heat, which is further converted to a pressure rise via thermo-elastic expansion. The initial pressure rise - determined by the local optical absorption coefficient (μ â ), fluence (ψ) and other thermal and mechanical properties - propagates as an ultrasonic wave, which is referred to as a photoacoustic wave.

  10. RF tomography of metallic objects in free space: preliminary results

    NASA Astrophysics Data System (ADS)

    Li, Jia; Ewing, Robert L.; Berdanier, Charles; Baker, Christopher

    2015-05-01

    RF tomography has great potential in defense and homeland security applications. A distributed sensing research facility is under development at Air Force Research Lab. To develop a RF tomographic imaging system for the facility, preliminary experiments have been performed in an indoor range with 12 radar sensors distributed on a circle of 3m radius. Ultra-wideband pulses are used to illuminate single and multiple metallic targets. The echoes received by distributed sensors were processed and combined for tomography reconstruction. Traditional matched filter algorithm and truncated singular value decomposition (SVD) algorithm are compared in terms of their complexity, accuracy, and suitability for distributed processing. A new algorithm is proposed for shape reconstruction, which jointly estimates the object boundary and scatter points on the waveform's propagation path. The results show that the new algorithm allows accurate reconstruction of object shape, which is not available through the matched filter and truncated SVD algorithms.

  11. Quasi In-Focus Optical Coherence Tomography

    NASA Astrophysics Data System (ADS)

    Ohmi, Masato; Kurata, Takayuki; Sekimoto, Mitsugu; Haruna, Masamitsu

    2004-02-01

    We propose here a unique method for in-focus imaging over the entire cross-sectional area of interest. This is the so-called quasi in-focus optical coherence tomography (OCT) or multiple OCT in which OCT images are obtained by shifting the focal plane of an objective, followed by piling up of these OCT images. A preliminary experiment was made using chicken tissue as a sample; as a result, a stripe pattern of fibrous muscle was clearly observed over a depth of more than 3 mm. In in-vitro tomographic imaging of the human stomach wall, quasi in-focus OCT can provide a very clear image of the muscularis mucosae, which is a bending film like tissue of a few tens of microns thickness, showing that our method is useful for the early-stage diagnosis of stomach cancer.

  12. Television Quiz Show Simulation

    ERIC Educational Resources Information Center

    Hill, Jonnie Lynn

    2007-01-01

    This article explores the simulation of four television quiz shows for students in China studying English as a foreign language (EFL). It discusses the adaptation and implementation of television quiz shows and how the students reacted to them.

  13. Positron Emission Tomography (PET)

    DOE R&D Accomplishments Database

    Welch, M. J.

    1990-01-01

    Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET.

  14. Positron Emission Tomography (PET)

    SciTech Connect

    Welch, M.J.

    1990-01-01

    Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET. 22 figs.

  15. The Art Show

    ERIC Educational Resources Information Center

    Scolarici, Alicia

    2004-01-01

    This article describes what once was thought to be impossible--a formal art show extravaganza at an elementary school with 1,000 students, a Department of Defense Dependent School (DODDS) located overseas, on RAF Lakenheath, England. The dream of this this event involved the transformation of the school cafeteria into an elegant art show

  16. Role of positron emission tomography/computed tomography in bone malignancies.

    PubMed

    Peller, Patrick J

    2013-09-01

    This article presents an overview of positron emission tomography combined with computed tomography (PET/CT) imaging of bone tumors for the practicing radiologist. The clinical roles and utility of (18)F-labeled fluorodeoxyglucose PET/CT in patients with primary bone tumors, osseous metastases, and multiple myeloma are reviewed. The clinical and research data supporting the utility of PET/CT in the evaluation of skeletal malignancies continues to grow. PMID:24010909

  17. Diffraction tomography of strain

    NASA Astrophysics Data System (ADS)

    Lionheart, W. R. B.; Withers, P. J.

    2015-04-01

    We consider whether it is possible to recover the three dimensional strain field tomographically from neutron and x-ray diffraction data for polycrystalline materials. We show that the distribution of strain transverse to a ray cannot be deduced from one diffraction pattern accumulated along that path, but that a certain moment of that data corresponds to the transverse ray transform of the strain tensor and so may be recovered by inverting that transform given sufficient data. We show that the whole strain tensor can be reconstructed from diffraction data measured using rotations about six directions that do not lie on a projective conic. In addition we give an inversion formula for complete data for the transverse ray transform. We also show that Bragg edge transmission data, which has been suggested for strain tomography with polychromatic data, cannot provide the strain distribution within the material but only the average along the ray path.

  18. A Holographic Road Show.

    ERIC Educational Resources Information Center

    Kirkpatrick, Larry D.; Rugheimer, Mac

    1979-01-01

    Describes the viewing sessions and the holograms of a holographic road show. The traveling exhibits, believed to stimulate interest in physics, include a wide variety of holograms and demonstrate several physical principles. (GA)

  19. Tackling multiple antibiotic resistance in enteropathogenic Escherichia coli (EPEC) clinical isolates: a diarylheptanoid from Alpinia officinarum shows promising antibacterial and immunomodulatory activity against EPEC and its lipopolysaccharide-induced inflammation.

    PubMed

    Subramanian, Krishnan; Selvakkumar, Chinnasamy; Vinaykumar, Kontham Sanathkumar; Goswami, Nabajyoti; Meenakshisundaram, Sankaranarayanan; Balakrishnan, Arun; Lakshmi, Baddireddi Subhadra

    2009-03-01

    Antibiotic treatment for infectious diseases commonly leads to host inflammatory responses. Molecules with bifunctional antibacterial and anti-inflammatory properties could provide a solution for such clinical manifestations. Here we report such bifunctional activity for a diarylheptanoid (5-hydroxy-7-(4''-hydroxy-3-methoxyphenyl)-1-phenyl-3-heptanone) isolated from Alpinia officinarum, a medicinal plant belonging to the Zingiberaceae family, against enteropathogenic Escherichia coli (EPEC). The diarylheptanoid showed inhibitory and bactericidal activity against EPEC clinical isolates and efficiently suppressed EPEC lipopolysaccharide-induced inflammation in human peripheral blood mononuclear cells. In silico docking analysis revealed that the diarylheptanoid could interact with subunit A of E. coli DNA gyrase. Such molecules with bifunctional activity may be potential therapeutics for infectious diseases. PMID:19095411

  20. Flow-scanning optical tomography.

    PubMed

    Pgard, Nicolas C; Toth, Marton L; Driscoll, Monica; Fleischer, Jason W

    2014-12-01

    We present a 3D tomography technique for in vivo observation of microscopic samples. The method combines flow in a microfluidic channel, illumination through a slit aperture, and a Fourier lens for simultaneous acquisition of multiple perspective angles in the phase-space domain. The technique is non-invasive and naturally robust to parasitic sample motion. 3D absorption is retrieved using standard back-projection algorithms, here a limited-domain inverse radon transform. Simultaneously, 3D differential phase contrast images are obtained by computational refocusing and comparison of complementary illumination angles. We implement the technique on a modified glass slide which can be mounted directly on existing optical microscopes. We demonstrate both amplitude and phase tomography on live, freely swimming C. elegans nematodes. PMID:25256716

  1. Plant Sterol Metabolism. ?7-Sterol-C5-Desaturase (STE1/DWARF7), ?5,7-Sterol-?7-Reductase (DWARF5) and ?24-Sterol-?24-Reductase (DIMINUTO/DWARF1) Show Multiple Subcellular Localizations in Arabidopsis thaliana (Heynh) L

    PubMed Central

    Silvestro, Daniele; Andersen, Tonni Grube; Schaller, Hubert; Jensen, Poul Erik

    2013-01-01

    Sterols are crucial lipid components that regulate membrane permeability and fluidity and are the precursors of bioactive steroids. The plant sterols exist as three major forms, free sterols, steryl glycosides and steryl esters. The storage of steryl esters in lipid droplets has been shown to contribute to cellular sterol homeostasis. To further document cellular aspects of sterol biosynthesis in plants, we addressed the question of the subcellular localization of the enzymes implicated in the final steps of the post-squalene biosynthetic pathway. In order to create a clear localization map of steroidogenic enzymes in cells, the coding regions of ?7-sterol-C5-desaturase (STE1/DWARF7), ?24-sterol-?24-reductase (DIMINUTO/DWARF1) and ?5,7-sterol-?7-reductase (DWARF5) were fused to the yellow fluorescent protein (YFP) and transformed into Arabidopsis thaliana mutant lines deficient in the corresponding enzymes. All fusion proteins were found to localize in the endoplasmic reticulum in functionally complemented plants. The results show that both ?5,7-sterol-?7-reductase and ?24-sterol-?24-reductase are in addition localized to the plasma membrane, whereas ?7-sterol-C5-desaturase was clearly detected in lipid particles. These findings raise new challenging questions about the spatial and dynamic cellular organization of sterol biosynthesis in plants. PMID:23409184

  2. Computed tomography findings of paracoccidiodomycosis in musculoskeletal system

    PubMed Central

    Lima Júnior, Francisco Valtenor Araújo; Savarese, Leonor Garbin; Monsignore, Lucas Moretti; Martinez, Roberto; Nogueira-Barbosa, Marcello Henrique

    2015-01-01

    Objective To evaluate musculoskeletal involvement in paracoccidioidomycosis at computed tomography. Materials and Methods Development of a retrospective study based on a review of radiologic and pathologic reports in the institution database. Patients with histopathologically confirmed musculoskeletal paracoccidioidomycosis and submitted to computed tomography were included in the present study. The imaging findings were consensually described by two radiologists. In order to avoid bias in the analysis, one patient with uncountable bone lesions was excluded from the study. Results A total of seven patients were included in the present study. A total of 18 bone lesions were counted. The study group consisted of 7 patients. A total number of 18 bone lesions were counted. Osteoarticular lesions were the first manifestation of the disease in four patients (57.14%). Bone lesions were multiple in 42.85% of patients. Appendicular and axial skeleton were affected in 85.71% and 42.85% of cases, respectively. Bone involvement was characterized by well-demarcated osteolytic lesions. Marginal osteosclerosis was identified in 72.22% of the lesions, while lamellar periosteal reaction and soft tissue component were present in 5.55% of them. One patient showed multiple small lesions with bone sequestra. Conclusion Paracoccidioidomycosis can be included in the differential diagnosis of either single or multiple osteolytic lesions in young patients even in the absence of a previous diagnosis of pulmonary or visceral paracoccidioidomycosis PMID:25798000

  3. Talk Show Science.

    ERIC Educational Resources Information Center

    Moore, Mitzi Ruth

    1992-01-01

    Proposes having students perform skits in which they play the roles of the science concepts they are trying to understand. Provides the dialog for a skit in which hot and cold gas molecules are interviewed on a talk show to study how these properties affect wind, rain, and other weather phenomena. (MDH)

  4. Obesity in show cats.

    PubMed

    Corbee, R J

    2014-12-01

    Obesity is an important disease with a high prevalence in cats. Because obesity is related to several other diseases, it is important to identify the population at risk. Several risk factors for obesity have been described in the literature. A higher incidence of obesity in certain cat breeds has been suggested. The aim of this study was to determine whether obesity occurs more often in certain breeds. The second aim was to relate the increased prevalence of obesity in certain breeds to the official standards of that breed. To this end, 268 cats of 22 different breeds investigated by determining their body condition score (BCS) on a nine-point scale by inspection and palpation, at two different cat shows. Overall, 45.5% of the show cats had a BCS > 5, and 4.5% of the show cats had a BCS > 7. There were significant differences between breeds, which could be related to the breed standards. Most overweight and obese cats were in the neutered group. It warrants firm discussions with breeders and cat show judges to come to different interpretations of the standards in order to prevent overweight conditions in certain breeds from being the standard of beauty. Neutering predisposes for obesity and requires early nutritional intervention to prevent obese conditions. PMID:24612018

  5. Showing What They Know

    ERIC Educational Resources Information Center

    Cech, Scott J.

    2008-01-01

    Having students show their skills in three dimensions, known as performance-based assessment, dates back at least to Socrates. Individual schools such as Barrington High School--located just outside of Providence--have been requiring students to actively demonstrate their knowledge for years. The Rhode Island's high school graduating class became

  6. The Ozone Show.

    ERIC Educational Resources Information Center

    Mathieu, Aaron

    2000-01-01

    Uses a talk show activity for a final assessment tool for students to debate about the ozone hole. Students are assessed on five areas: (1) cooperative learning; (2) the written component; (3) content; (4) self-evaluation; and (5) peer evaluation. (SAH)

  7. Stage a Water Show

    ERIC Educational Resources Information Center

    Frasier, Debra

    2008-01-01

    In the author's book titled "The Incredible Water Show," the characters from "Miss Alaineus: A Vocabulary Disaster" used an ocean of information to stage an inventive performance about the water cycle. In this article, the author relates how she turned the story into hands-on science teaching for real-life fifth-grade students. The author also…

  8. Show Them the Money.

    ERIC Educational Resources Information Center

    Levine, Elliott

    2002-01-01

    Strategies to help garner community support in school technology growth or maintenance include the following: (1) consider a "current state of technology" report; (2) forget five-year plans; (3) develop annual technology reports; (4) look to your website; (5) seek constructive opportunities to share technology, and (6) show off best examples at

  9. Volumetric magnetic induction tomography

    NASA Astrophysics Data System (ADS)

    Wei, H.-Y.; Ma, L.; Soleimani, M.

    2012-05-01

    Magnetic induction tomography (MIT) is a new and emerging type of tomography technique that is able to map the passive electromagnetic properties (in particular conductivity) of an object. Because of its non-invasive feature, it becomes a suitable technique for many industries, such as metal processing and mining. This paper presents a volumetric MIT (VMIT) system based on an existing measurement setup in our 2D system (MIT Mk-I). By increasing the number of sensors in the axial direction, volumetric imaging can be realized and hence can improve the spatial resolution of the reconstructed images. All of the system control, data acquisition and signal demodulation are accomplished by a commercial data acquisition card and the National Instruments graphical programming language. In this paper, both the system architecture and the forward 3D sensitivity model will be presented. The image reconstruction scheme is modified by introducing a 3D sensitivity map to replace the previous 2D sensitivity map used for the MIT Mk-I system. The iterative Landweber technique was implemented as the inverse solver to reconstruct the images. Several laboratory-based experimental results are demonstrated in this paper, with different shapes of imaging objects. The reconstructed images are satisfactory showing for the first time volumetric conductivity reconstruction using a multi-layer MIT system. The results indicate the high-quality image reconstruction using our novel VMIT system for potential use in industrial applications, such as metal flow imaging.

  10. Obesity in show dogs.

    PubMed

    Corbee, R J

    2012-08-11

    Obesity is an important disease with a growing incidence. Because obesity is related to several other diseases, and decreases life span, it is important to identify the population at risk. Several risk factors for obesity have been described in the literature. A higher incidence of obesity in certain breeds is often suggested. The aim of this study was to determine whether obesity occurs more often in certain breeds. The second aim was to relate the increased prevalence of obesity in certain breeds to the official standards of that breed. To this end, we investigated 1379 dogs of 128 different breeds by determining their body condition score (BCS). Overall, 18.6% of the show dogs had a BCS >5, and 1.1% of the show dogs had a BCS>7. There were significant differences between breeds, which could be correlated to the breed standards. It warrants firm discussions with breeders and judges in order to come to different interpretations of the standards to prevent overweight conditions from being the standard of beauty. PMID:22882163

  11. Diffuse nesidioblastosis diagnosed on a Ga-68 DOTATATE positron emission tomography/computerized tomography.

    PubMed

    Arun, Sasikumar; Rai Mittal, Bhagwant; Shukla, Jaya; Bhattacharya, Anish; Kumar, Praveen

    2013-07-01

    The authors describe a 50 days old pre-term infant with persistent hyperinsulinemic hypoglycemia of infancy in whom Ga-68 DOTATATE positron emission tomography/computerized tomography scan showed diffusely increased tracer uptake in the entire pancreas with no abnormal tracer uptake anywhere else in the body, suggestive of a diffuse variant of nesidioblastosis. PMID:24250024

  12. Optofluidic Tomography on a Chip

    NASA Astrophysics Data System (ADS)

    Isikman, Serhan O.; Bishara, Waheb; Zhu, Hongying; Ozcan, Aydogan

    2011-04-01

    Using lensfree holography we demonstrate optofluidic tomography on a chip. A partially coherent light source is utilized to illuminate the objects flowing within a microfluidic channel placed directly on a digital sensor array. The light source is rotated to record lensfree holograms of the objects at different viewing directions. By capturing multiple frames at each illumination angle, pixel super-resolution techniques are utilized to reconstruct high-resolution transmission images at each angle. Tomograms of flowing objects are then computed through filtered back-projection of these reconstructed lensfree images, thereby enabling optical sectioning on-a-chip. The proof-of-concept is demonstrated by lensfree tomographic imaging of C. elegans.

  13. Turbocharging Quantum Tomography.

    SciTech Connect

    Blume-Kohout, Robin J; Gamble, John King,; Nielsen, Erik; Maunz, Peter Lukas Wilhelm; Scholten, Travis L.; Rudinger, Kenneth Michael

    2015-01-01

    Quantum tomography is used to characterize quantum operations implemented in quantum information processing (QIP) hardware. Traditionally, state tomography has been used to characterize the quantum state prepared in an initialization procedure, while quantum process tomography is used to characterize dynamical operations on a QIP system. As such, tomography is critical to the development of QIP hardware (since it is necessary both for debugging and validating as-built devices, and its results are used to influence the next generation of devices). But tomography su %7C ers from several critical drawbacks. In this report, we present new research that resolves several of these flaws. We describe a new form of tomography called gate set tomography (GST), which unifies state and process tomography, avoids prior methods critical reliance on precalibrated operations that are not generally available, and can achieve unprecedented accuracies. We report on theory and experimental development of adaptive tomography protocols that achieve far higher fidelity in state reconstruction than non-adaptive methods. Finally, we present a new theoretical and experimental analysis of process tomography on multispin systems, and demonstrate how to more e %7C ectively detect and characterize quantum noise using carefully tailored ensembles of input states.

  14. Improving spatial resolution and contrast in ultrasound modulated optical tomography

    NASA Astrophysics Data System (ADS)

    Huynh, N. T.; Ruan, H.; Mather, M. L.; Hayes-Gill, B. R.; Morgan, S. P.

    2012-02-01

    Ultrasound imaging has benefited from non-linear approaches to improve image resolution and reduce the effects of side-lobes. A system for performing second harmonic ultrasound modulated optical tomography is demonstrated which incorporates both pulsed optical illumination and acoustic excitation. A pulse acoustic inversion scheme is employed which allows the second harmonic ultrasound modulated optical signal to be obtained while still maintaining a short pulse length of the acoustic excitation. For the experiments carried out the method demonstrates a reduction in the effective line spread function from 4mm for the fundamental to 2.4mm for the second harmonic. The first use of pulsed ultrasound modulated optical tomography in imaging fluorescent targets is also discussed. Simple experiments show that by changing the length of the acoustic pulse the image contrast can be optimized. The modulation depth of the detected signal is greatest when the length of the object along the acoustic axis is an odd number of half wavelengths and is weakest when the object is an integer multiple of an acoustic wavelength. Preliminary ultrasound modulated imaging results are also presented where the target generates light within the medium without the use of an external light source. Although signal to noise ratio is likely to be a major challenge, this result highlights a potentially useful application of ultrasound modulated optical tomography in bio- or chemi-luminescence imaging.

  15. Mycosis fungoides: Positron emission tomography/computed tomography in staging and monitoring the effect of therapy

    PubMed Central

    DSouza, Maria Mathew; DSouza, Paschal; Sharma, Rajnish; Jaimini, Abhinav; Mondal, Anupam

    2015-01-01

    A 58-year-old woman, diagnosed as a case of mycosis fungoides (MF), underwent [18F]-fluoro-D-glucose positron emission tomography/computed tomography (FDG PET/CT) examination. The study revealed intense FDG uptake in a large ulceroproliferative right thigh lesion, indurated plaques in the chest wall and left thigh, along with multiple sites of cutaneous involvement, axillary and inguinal lymphadenopathy. The patient underwent chemotherapy with CHOP regimen, radiotherapy for the right thigh lesion, along with topical corticosteroids and emollients for the disseminated cutaneous involvement. Repeat [18F]-FDG PET/CT study performed a year later, showed near complete disease regression specifically of the ulceroproliferative lesion and indurated cutaneous plaques, no change in lymphadenopathy, and a subtle diffuse progression of the remaining cutaneous lesions. A multidisciplinary approach to the diagnosis, staging and treatment of MF has long been suggested for optimizing outcomes from management of patients with this disease. This case highlights the potential role of incorporating PET/CT as a single modality imaging technique in the staging and assessment of response to therapy. PMID:25829740

  16. Public medical shows.

    PubMed

    Walusinski, Olivier

    2014-01-01

    In the second half of the 19th century, Jean-Martin Charcot (1825-1893) became famous for the quality of his teaching and his innovative neurological discoveries, bringing many French and foreign students to Paris. A hunger for recognition, together with progressive and anticlerical ideals, led Charcot to invite writers, journalists, and politicians to his lessons, during which he presented the results of his work on hysteria. These events became public performances, for which physicians and patients were transformed into actors. Major newspapers ran accounts of these consultations, more like theatrical shows in some respects. The resultant enthusiasm prompted other physicians in Paris and throughout France to try and imitate them. We will compare the form and substance of Charcot's lessons with those given by Jules-Bernard Luys (1828-1897), Victor Dumontpallier (1826-1899), Ambroise-Auguste Libault (1823-1904), Hippolyte Bernheim (1840-1919), Joseph Grasset (1849-1918), and Albert Pitres (1848-1928). We will also note their impact on contemporary cinema and theatre. PMID:25273491

  17. The Great Cometary Show

    NASA Astrophysics Data System (ADS)

    2007-01-01

    The ESO Very Large Telescope Interferometer, which allows astronomers to scrutinise objects with a precision equivalent to that of a 130-m telescope, is proving itself an unequalled success every day. One of the latest instruments installed, AMBER, has led to a flurry of scientific results, an anthology of which is being published this week as special features in the research journal Astronomy & Astrophysics. ESO PR Photo 06a/07 ESO PR Photo 06a/07 The AMBER Instrument "With its unique capabilities, the VLT Interferometer (VLTI) has created itself a niche in which it provide answers to many astronomical questions, from the shape of stars, to discs around stars, to the surroundings of the supermassive black holes in active galaxies," says Jorge Melnick (ESO), the VLT Project Scientist. The VLTI has led to 55 scientific papers already and is in fact producing more than half of the interferometric results worldwide. "With the capability of AMBER to combine up to three of the 8.2-m VLT Unit Telescopes, we can really achieve what nobody else can do," added Fabien Malbet, from the LAOG (France) and the AMBER Project Scientist. Eleven articles will appear this week in Astronomy & Astrophysics' special AMBER section. Three of them describe the unique instrument, while the other eight reveal completely new results about the early and late stages in the life of stars. ESO PR Photo 06b/07 ESO PR Photo 06b/07 The Inner Winds of Eta Carinae The first results presented in this issue cover various fields of stellar and circumstellar physics. Two papers deal with very young solar-like stars, offering new information about the geometry of the surrounding discs and associated outflowing winds. Other articles are devoted to the study of hot active stars of particular interest: Alpha Arae, Kappa Canis Majoris, and CPD -57o2874. They provide new, precise information about their rotating gas envelopes. An important new result concerns the enigmatic object Eta Carinae. Using AMBER with its high spatial and spectral resolution, it was possible to zoom into the very heart of this very massive star. In this innermost region, the observations are dominated by the extremely dense stellar wind that totally obscures the underlying central star. The AMBER observations show that this dense stellar wind is not spherically symmetric, but exhibits a clearly elongated structure. Overall, the AMBER observations confirm that the extremely high mass loss of Eta Carinae's massive central star is non-spherical and much stronger along the poles than in the equatorial plane. This is in agreement with theoretical models that predict such an enhanced polar mass-loss in the case of rapidly rotating stars. ESO PR Photo 06c/07 ESO PR Photo 06c/07 RS Ophiuchi in Outburst Several papers from this special feature focus on the later stages in a star's life. One looks at the binary system Gamma 2 Velorum, which contains the closest example of a star known as a Wolf-Rayet. A single AMBER observation allowed the astronomers to separate the spectra of the two components, offering new insights in the modeling of Wolf-Rayet stars, but made it also possible to measure the separation between the two stars. This led to a new determination of the distance of the system, showing that previous estimates were incorrect. The observations also revealed information on the region where the winds from the two stars collide. The famous binary system RS Ophiuchi, an example of a recurrent nova, was observed just 5 days after it was discovered to be in outburst on 12 February 2006, an event that has been expected for 21 years. AMBER was able to detect the extension of the expanding nova emission. These observations show a complex geometry and kinematics, far from the simple interpretation of a spherical fireball in extension. AMBER has detected a high velocity jet probably perpendicular to the orbital plane of the binary system, and allowed a precise and careful study of the wind and the shockwave coming from the nova. The stream of results from the VLTI and AMBER

  18. Optical coherency matrix tomography

    NASA Astrophysics Data System (ADS)

    Kagalwala, Kumel H.; Kondakci, H. Esat; Abouraddy, Ayman F.; Saleh, Bahaa E. A.

    2015-10-01

    The coherence of an optical beam having multiple degrees of freedom (DoFs) is described by a coherency matrix G spanning these DoFs. This optical coherency matrix has not been measured in its entirety to dateeven in the simplest case of two binary DoFs where G is a 4??4 matrix. We establish a methodical yet versatile approachoptical coherency matrix tomographyfor reconstructing G that exploits the analogy between this problem in classical optics and that of tomographically reconstructing the density matrix associated with multipartite quantum states in quantum information science. Here G is reconstructed from a minimal set of linearly independent measurements, each a cascade of projective measurements for each DoF. We report the first experimental measurements of the 4??4 coherency matrix G associated with an electromagnetic beam in which polarization and a spatial DoF are relevant, ranging from the traditional two-point Youngs double slit to spatial parity and orbital angular momentum modes.

  19. Optical coherency matrix tomography

    PubMed Central

    Kagalwala, Kumel H.; Kondakci, H. Esat; Abouraddy, Ayman F.; Saleh, Bahaa E. A.

    2015-01-01

    The coherence of an optical beam having multiple degrees of freedom (DoFs) is described by a coherency matrix G spanning these DoFs. This optical coherency matrix has not been measured in its entirety to dateeven in the simplest case of two binary DoFs where G is a 4??4 matrix. We establish a methodical yet versatile approachoptical coherency matrix tomographyfor reconstructing G that exploits the analogy between this problem in classical optics and that of tomographically reconstructing the density matrix associated with multipartite quantum states in quantum information science. Here G is reconstructed from a minimal set of linearly independent measurements, each a cascade of projective measurements for each DoF. We report the first experimental measurements of the 4??4 coherency matrix G associated with an electromagnetic beam in which polarization and a spatial DoF are relevant, ranging from the traditional two-point Youngs double slit to spatial parity and orbital angular momentum modes. PMID:26478452

  20. Spectral thresholding quantum tomography for low rank states

    NASA Astrophysics Data System (ADS)

    Butucea, Cristina; Gu??, M?d?lin; Kypraios, Theodore

    2015-11-01

    The estimation of high dimensional quantum states is an important statistical problem arising in current quantum technology applications. A key example is the tomography of multiple ions states, employed in the validation of state preparation in ion trap experiments (Hffner et al 2005 Nature 438 643). Since full tomography becomes unfeasible even for a small number of ions, there is a need to investigate lower dimensional statistical models which capture prior information about the state, and to devise estimation methods tailored to such models. In this paper we propose several new methods aimed at the efficient estimation of low rank states and analyse their performance for multiple ions tomography. All methods consist in first computing the least squares estimator, followed by its truncation to an appropriately chosen smaller rank. The latter is done by setting eigenvalues below a certain noise level to zero, while keeping the rest unchanged, or normalizing them appropriately. We show that (up to logarithmic factors in the space dimension) the mean square error of the resulting estimators scales as r\\cdot d/N where r is the rank, d={2}k is the dimension of the Hilbert space, and N is the number of quantum samples. Furthermore we establish a lower bound for the asymptotic minimax risk which shows that the above scaling is optimal. The performance of the estimators is analysed in an extensive simulations study, with emphasis on the dependence on the state rank, and the number of measurement repetitions. We find that all estimators perform significantly better than the least squares, with the physical estimator (which is a bona fide density matrix) slightly outperforming the other estimators.

  1. Cognitive Tomography Reveals Complex, Task-Independent Mental Representations

    PubMed Central

    Houlsby, NeilM.T.; Huszr, Ferenc; Ghassemi, MohammadM.; Orbn, Gerg?; Wolpert, DanielM.; Lengyel, Mt

    2013-01-01

    Summary Humans develop rich mental representations that guide their behavior in a variety of everyday tasks. However, it is unknown whether these representations, often formalized as priors in Bayesian inference, are specific for each task or subserve multiple tasks. Current approaches cannot distinguish between these two possibilities because they cannot extract comparable representations across different tasks [110]. Here, we develop a novel method, termed cognitive tomography, that can extract complex, multidimensional priors across tasks. We apply this method to human judgments in two qualitatively different tasks, familiarity and odd one out, involving an ecologically relevant set of stimuli, human faces. We show that priors over faces are structurally complex and vary dramatically across subjects, but are invariant across the tasks within each subject. The priors we extract from each task allow us to predict with high precision the behavior of subjects for novel stimuli both in the same task as well as in the other task. Our results provide the first evidence for a single high-dimensional structured representation of a naturalistic stimulus set that guides behavior in multiple tasks. Moreover, the representations estimated by cognitive tomography can provide independent, behavior-based regressors for elucidating the neural correlates of complex naturalistic priors. PMID:24354016

  2. Dual seven pinhole tomography

    SciTech Connect

    Bizais, Y.; Zubal, I.G.; Rowe, R.W.; Bennett, G.W.; Brill, A.B.

    1982-01-01

    Emission tomography using two orthogonal sets of projections through seven pinhole collimators is considered. This paper describes the acquisition system, the reconstruction algorithm, presents results obtained in phantom studies, and discusses the advantages and disadvantages of this method over conventional Seven Pinhole Tomography.

  3. Optical coherence tomography helps differentiate neuromyelitis optica and MS optic neuropathies

    PubMed Central

    Ratchford, J N.; Quigg, M E.; Conger, A; Frohman, T; Frohman, E; Balcer, L J.; Calabresi, P A.; Kerr, D A.

    2009-01-01

    Objective: To evaluate the retinal nerve fiber layer (RNFL) thickness and macular volume in neuromyelitis optica (NMO) spectrum patients using optical coherence tomography (OCT). Background: OCT can quantify damage to retinal ganglion cell axons and can identify abnormalities in multiple sclerosis and optic neuritis (ON) eyes. OCT may also be useful in the evaluation of patients with NMO. Methods: OCT and visual function testing were performed in 26 NMO spectrum patients with a history of ON, 17 patients with isolated longitudinally extensive transverse myelitis (LETM) without ON, 378 patients with relapsing–remitting multiple sclerosis (RRMS), and 77 healthy controls at 2 centers. Results: Substantial RNFL thinning was seen in NMO ON eyes (63.6 μm) relative to both RRMS ON eyes (88.3 μm, p < 0.0001) and control eyes (102.4 μm, p < 0.0001). A first episode of ON was estimated to cause 24 μm more loss of RNFL thickness in NMO than RRMS. Similar results were seen for macular volume. ON also was associated with more severe visual impairment in NMO spectrum patients than in RRMS patients. Eyes in the LETM group and unaffected NMO eyes were not significantly different from controls, though conclusions about these subgroups were limited by small sample sizes. Conclusions: Optical coherence tomography (OCT) shows more severe retinal damage after optic neuritis (ON) episodes in neuromyelitis optica (NMO) than in relapsing–remitting multiple sclerosis. Identification of substantial retinal nerve fiber layer loss (>15 μm) after ON in a non–multiple sclerosis patient should prompt consideration of an NMO spectrum condition. OCT may be a useful tool for the evaluation of patients with NMO. GLOSSARY CI = confidence interval; ETDRS = Early Treatment Diabetic Retinopathy Study; IgG = immunoglobulin G; LETM = longitudinally extensive transverse myelitis; MS = multiple sclerosis; NMO = neuromyelitis optica; OCT = optical coherence tomography; ON = optic neuritis; RNFL = retinal nerve fiber layer; RRMS = relapsing–remitting multiple sclerosis. PMID:19636050

  4. Maxillary Swelling as the First Evidence of Multiple Myeloma.

    PubMed

    Kasamatsu, Atsushi; Kimura, Yasushi; Tsujimura, Hideki; Kanazawa, Harusachi; Koide, Nao; Miyamoto, Isao; Endo-Sakamoto, Yosuke; Shiiba, Masashi; Tanzawa, Hideki; Uzawa, Katsuhiro

    2015-01-01

    Multiple myeloma is a malignant neoplasm of plasma cells characterized by proliferation of a single clone of abnormal immunoglobulin-secreting plasma cells. Since the amount of hemopoietic bone marrow is decreased in the maxilla, oral manifestations of multiple myeloma are less common in the maxilla than in the mandible. We report the case of 33-year-old Japanese man who presented with a mass in the right maxillary alveolar region. Computed tomography and magnetic resonance images showed a soft tissue mass in the right maxilla eroding the anterior and lateral walls of the maxillary sinus and extending into the buccal space. The biopsy results, imaging, and laboratory investigations led to the diagnosis of multiple myeloma. This case report suggests that oral surgeons and dentists should properly address oral manifestations as first indications of multiple myeloma. PMID:26640721

  5. Maxillary Swelling as the First Evidence of Multiple Myeloma

    PubMed Central

    Kasamatsu, Atsushi; Kimura, Yasushi; Tsujimura, Hideki; Kanazawa, Harusachi; Koide, Nao; Miyamoto, Isao; Endo-Sakamoto, Yosuke; Shiiba, Masashi; Tanzawa, Hideki; Uzawa, Katsuhiro

    2015-01-01

    Multiple myeloma is a malignant neoplasm of plasma cells characterized by proliferation of a single clone of abnormal immunoglobulin-secreting plasma cells. Since the amount of hemopoietic bone marrow is decreased in the maxilla, oral manifestations of multiple myeloma are less common in the maxilla than in the mandible. We report the case of 33-year-old Japanese man who presented with a mass in the right maxillary alveolar region. Computed tomography and magnetic resonance images showed a soft tissue mass in the right maxilla eroding the anterior and lateral walls of the maxillary sinus and extending into the buccal space. The biopsy results, imaging, and laboratory investigations led to the diagnosis of multiple myeloma. This case report suggests that oral surgeons and dentists should properly address oral manifestations as first indications of multiple myeloma. PMID:26640721

  6. Diverse Findings in Calcified Thrombus Between Histopathology and In Vivo Imaging Including Intravascular Ultrasound, Optical Coherence Tomography, and Angioscopy.

    PubMed

    Koga, Seiji; Ikeda, Satoshi; Nakata, Tomoo; Kawano, Hiroaki; Abe, Kuniko; Maemura, Koji

    2015-12-01

    A 46-year-old woman on hemodialysis due to end-stage renal disease was admitted for repeated thrombus formation in previously implanted drug-eluting stents in the right coronary artery. We could successfully aspirate this thrombus, and histopathology revealed a calcified thrombus comprising multiple microcalcifications and fibrinous materials. This is the first report showing how a calcified thrombus is visualized in vivo by intracoronary imaging modalities including intravascular ultrasound, optical coherence tomography, and angioscopy. PMID:26549397

  7. Wegener's granulomatosis detected initially by integrated 18F-fluorodeoxyglucose positron emission tomography/computed tomography.

    PubMed

    Ueda, Naoyasu; Inoue, Yasushi; Himeji, Daisuke; Shimao, Yoshiya; Oryoji, Kensuke; Mitoma, Hiroki; Arinobu, Yojiro; Niiro, Hiroaki; Tsukamoto, Hiroshi; Horiuchi, Takahiko; Ueda, Akira; Akashi, Koichi

    2010-04-01

    Early diagnosis is crucial for effective treatment of Wegener's granulomatosis, although this disease shows only atypical symptoms in the primary stage. This report describes a patient suspected of having a malignancy based on integrated 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT), which showed increased uptake in pulmonary nodules and nasopharyngeal mucosa. Integrated PET/CT is therefore considered to be useful to confirm the distribution and determine the optimal site for biopsy. PMID:20012458

  8. China Amplitude Tomography

    NASA Astrophysics Data System (ADS)

    Hearn, T. M.

    2014-12-01

    Modern data from the China Bulletin and temporary network deployments has been used to update amplitude tomography using ML and MS seismic amplitudes. This work builds on the results of Hearn et al., 2008. ML attenuation estimates are much better resolved due to the inclusion of subnet data. We find that the trade-off between geometrical spreading and attenuation estimates are well constrained; however, both of these parameters have significant trade-off with the frequency dependence of attenuation. Maps of attenuation using the ML amplitudes are similar to those of Lg attenuation found by other authors suggesting that ML attenuation estimates form a suitable proxy for Lg attenuation estimates. We are now able to associate high attenuation directly with the Longmen Shan and the Qilian Shan mountains and also, where resolved, with the Kunlun Shan, Altyn Tag, and Tian Shan mountains. Grabens around the Ordos Platform also show high attenuation. Basins, however, do not in general show high attenuation. The main exception to this is the Bohai Basin. We conclude that the ML waveforms, like the Lg waveforms, interrogate the entire crustal column and are most sensitive to tectonically active structures and rapid changes in crustal structure. Data from MS data do not include subnet readings and do not have the resolution that was obtained with the ML data. Nonetheless, features are similar with the exception that basins appear more highly attenuative.

  9. Applied potential tomography. A new noninvasive technique for measuring gastric emptying.

    PubMed

    Avill, R; Mangnall, Y F; Bird, N C; Brown, B H; Barber, D C; Seagar, A D; Johnson, A G; Read, N W

    1987-04-01

    Applied potential tomography is a new, noninvasive technique that yields sequential images of the resistivity of gastric contents after subjects have ingested a liquid or semisolid meal. This study validates the technique as a means of measuring gastric emptying. Experiments in vitro showed an excellent correlation between measurements of resistivity and either the square of the radius of a glass rod or the volume of water in a spherical balloon when both were placed in an oval tank containing saline. Altering the lateral position of the rod in the tank did not alter the values obtained. Images of abdominal resistivity were also directly correlated with the volume of air in a gastric balloon. Profiles of gastric emptying of liquid meals obtained using applied potential tomography were very similar to those obtained using scintigraphy or dye dilution techniques, provided that acid secretion was inhibited by cimetidine. Profiles of emptying of a mashed potato meal using applied potential tomography were also very similar to those obtained by scintigraphy. Measurements of the emptying of a liquid meal from the stomach were reproducible if acid secretion was inhibited by cimetidine. Thus, applied potential tomography is an accurate and reproducible method of measuring gastric emptying of liquids and particulate food. It is inexpensive, well tolerated, easy to use, and ideally suited for multiple studies in patients, even those who are pregnant. PMID:3549419

  10. Single-cell diffraction tomography with optofluidic rotation about a tilted axis

    NASA Astrophysics Data System (ADS)

    Mller, Paul; Schrmann, Mirjam; Chan, Chii J.; Guck, Jochen

    2015-08-01

    Optical diffraction tomography (ODT) is a tomographic technique that can be used to measure the three-dimensional (3D) refractive index distribution within living cells without the requirement of any marker. In principle, ODT can be regarded as a generalization of optical projection tomography which is equivalent to computerized tomography (CT). Both optical tomographic techniques require projection-phase images of cells measured at multiple angles. However, the reconstruction of the 3D refractive index distribution post-measurement differs for the two techniques. It is known that ODT yields better results than projection tomography, because it takes into account diffraction of the imaging light due to the refractive index structure of the sample. Here, we apply ODT to biological cells in a microfluidic chip which combines optical trapping and microfluidic flow to achieve an optofluidic single-cell rotation. In particular, we address the problem that arises when the trapped cell is not rotating about an axis perpendicular to the imaging plane, but is instead arbitrarily tilted. In this paper we show that the 3D reconstruction can be improved by taking into account such a tilted rotational axis in the reconstruction process.

  11. Applied potential tomography. A new noninvasive technique for measuring gastric emptying

    SciTech Connect

    Avill, R.; Mangnall, Y.F.; Bird, N.C.; Brown, B.H.; Barber, D.C.; Seagar, A.D.; Johnson, A.G.; Read, N.W.

    1987-04-01

    Applied potential tomography is a new, noninvasive technique that yields sequential images of the resistivity of gastric contents after subjects have ingested a liquid or semisolid meal. This study validates the technique as a means of measuring gastric emptying. Experiments in vitro showed an excellent correlation between measurements of resistivity and either the square of the radius of a glass rod or the volume of water in a spherical balloon when both were placed in an oval tank containing saline. Altering the lateral position of the rod in the tank did not alter the values obtained. Images of abdominal resistivity were also directly correlated with the volume of air in a gastric balloon. Profiles of gastric emptying of liquid meals obtained using applied potential tomography were very similar to those obtained using scintigraphy or dye dilution techniques, provided that acid secretion was inhibited by cimetidine. Profiles of emptying of a mashed potato meal using applied potential tomography were also very similar to those obtained by scintigraphy. Measurements of the emptying of a liquid meal from the stomach were reproducible if acid secretion was inhibited by cimetidine. Thus, applied potential tomography is an accurate and reproducible method of measuring gastric emptying of liquids and particulate food. It is inexpensive, well tolerated, easy to use, and ideally suited for multiple studies in patients, even those who are pregnant.

  12. Wavelet-based time-dependent travel time tomography method and its application in imaging the Etna volcano in Italy

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Zhang, Haijiang

    2015-10-01

    It has been a challenge to image velocity changes in real time by seismic travel time tomography. If more seismic events are included in the tomographic system, the inverted velocity models do not have necessary time resolution to resolve velocity changes. But if fewer events are used for real-time tomography, the system is less stable and the inverted model may contain some artifacts, and thus, resolved velocity changes may not be real. To mitigate these issues, we propose a wavelet-based time-dependent double-difference (DD) tomography method. The new method combines the multiscale property of wavelet representation and the fast converging property of the simultaneous algebraic reconstruction technique to solve the velocity models at multiple scales for sequential time segments. We first test the new method using synthetic data constructed using real event and station distribution for Mount Etna volcano in Italy. Then we show its effectiveness to determine velocity changes for the 2001 and 2002 eruptions of Mount Etna volcano. Compared to standard DD tomography that uses seismic events from a longer time period, wavelet-based time-dependent tomography better resolves velocity changes that may be caused by fracture closure and opening as well as fluid migration before and after volcano eruptions.

  13. Hybrid single photon emission computed tomography/computed tomography sulphur colloid scintigraphy in focal nodular hyperplasia.

    PubMed

    Bhoil, Amit; Gayana, Shankramurthy; Sood, Ashwani; Bhattacharya, Anish; Mittal, Bhagwant Rai

    2013-09-01

    It is important to differentiate focal nodular hyperplasia (FNH), a benign condition of liver most commonly affecting women, from other neoplasm such as hepatic adenoma and metastasis. The functional reticuloendothelial features of FNH can be demonstrated by scintigraphy. We present a case of breast cancer in whom fluorodeoxyglucose positron emission tomography/computerized tomography (CT) showed a homogenous hyperdense lesion in liver, which on Tc99m sulfur colloid single-photon emission computed tomography/CT was found to have increased focal tracer uptake suggestive of FNH. PMID:25165424

  14. High rate of cardiac sarcoidosis presenting with cutaneous plaque type sarcoidosis in 18F-fluorodeoxyglucose positron emission tomography-computed tomography: a case series

    PubMed Central

    2014-01-01

    Introduction Myocardial sarcoidosis is known as a significant complication of sarcoidosis, but Holter electrocardiographic monitoring or echocardiograms might not be sensitive enough to detect cardiac involvement. While gallium scintigraphy has been recommended, 18F-fluorodeoxyglucose positron emission tomography-computed tomography might be more sensitive to detect sarcoidosis. Case presentations This report comprises the cases of 12 Japanese patients. Two were male, and ten were female. Their age range was between 32 and 93years. The average age of the patients was 63. We found internal involvement of sarcoidosis in eight (89%) of nine patients by positron emission tomography-computed tomography and in two (67%) of three patients by gallium scintigraphy. Myocardial sarcoidosis was detected in four (33%) of twelve patients, and specifically in three (75%) of four facial multiple plaque type sarcoidosis patients. Conclusion The myocardial lesions detected by positron emission tomography-computed tomography could not be detected with conventional electrocardiogram or echogram. Positron emission tomography-computed tomography can detect sarcoid lesions of the whole body and is useful for the follow up of patients. We recommend positron emission tomography-computed tomography for those patients having cutaneous sarcoidosis, especially facial multiple plaque type sarcoidosis. PMID:24428950

  15. Acoustic tomography. Laboratory technique Implementation.

    NASA Astrophysics Data System (ADS)

    Galvis, Jorge; Carvajal, Jenny

    2010-05-01

    From geomechanical tests carried out on rocks it is possible to determine its physico-mechanical properties, which relate the strain and applied stress; even so, conventional tests do not allow to identify how stress is distributed and how it has affected porous media. Today, techniques like acoustic tomography widely used in medicine, geophysics and others sciences, generates images by sections of the interior of a body. Acoustic tomography allows inferring the stress state within porous media; since wave velocities are closely related to media density, if a stress is applied to a rock, it will generate grains compaction and this will be showed by an increase of wave velocity. Implementation was conducted on rock plugs under diverse stress fields, simultaneously recording P-wave velocities (Compressional) on perpendicular planes to sample vertical axis. Transmission and reception of acoustic waves through porous media were done by piezoelectric crystals (PZT) used as sensors. A transmitting crystal excited by a voltage pulse causes a mechanical vibration, which travels across media; this is known as inverse piezoelectric effect. This vibration is recorded by a receiving crystal in which the direct piezoelectric effect appears; which dictates that if a piezoelectric is disturbed mechanically, an electrical signal between its terminals will appear. This electrical signal is used to obtain the wave velocity. Nevertheless, acoustic tomography corresponds to one of those called inverse Problems that arise when from observed data the model parameters must be obtained; in this way, tomography involves iterative reconstruction techniques (ART or SIRT) which are projections of observed data and its later inversion. Obtained results are cross-sectional images of velocity within the rock. In these images it is possible to identify where stress has a greater concentration observing the color map generated; thus, a greater velocity density area corresponding to a greater stress will be colored with a higher tonality within the palette used.

  16. 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.

  17. Optofluidic Tomography on a Chip

    PubMed Central

    Isikman, Serhan O.; Bishara, Waheb; Zhu, Hongying; Ozcan, Aydogan

    2011-01-01

    Using lensfree holography we demonstrate optofluidic tomography on a chip. A partially coherent light source is utilized to illuminate the objects flowing within a microfluidic channel placed directly on a digital sensor array. The light source is rotated to record lensfree holograms of the objects at different viewing directions. By capturing multiple frames at each illumination angle, pixel super-resolution techniques are utilized to reconstruct high-resolution transmission images at each angle. Tomograms of flowing objects are then computed through filtered back-projection of these reconstructed lensfree images, thereby enabling optical sectioning on-a-chip. The proof-of-concept is demonstrated by lensfree tomographic imaging of C. elegans. PMID:21580801

  18. X-ray tensor tomography

    NASA Astrophysics Data System (ADS)

    Malecki, A.; Potdevin, G.; Biernath, T.; Eggl, E.; Willer, K.; Lasser, T.; Maisenbacher, J.; Gibmeier, J.; Wanner, A.; Pfeiffer, F.

    2014-02-01

    Here we introduce a new concept for x-ray computed tomography that yields information about the local micro-morphology and its orientation in each voxel of the reconstructed 3D tomogram. Contrary to conventional x-ray CT, which only reconstructs a single scalar value for each point in the 3D image, our approach provides a full scattering tensor with multiple independent structural parameters in each volume element. In the application example shown in this study, we highlight that our method can visualize sub-pixel fiber orientations in a carbon composite sample, hence demonstrating its value for non-destructive testing applications. Moreover, as the method is based on the use of a conventional x-ray tube, we believe that it will also have a great impact in the wider range of material science investigations and in future medical diagnostics. The authors declare no competing financial interests.

  19. Algorithm for Rapid Tomography of Gas Concentrations

    SciTech Connect

    Price, P.N.; Fischer, M.L.; Gadgil, A.J.; Sextro, R.G.

    2000-06-27

    We present a new computed tomography method, the low third derivative (LTD) method, that is particularly suited for reconstructing the spatial distribution of gas concentrations from path-integral data for a small number of optical paths. The method finds a spatial distribution of gas concentrations that (1) has path integrals that agree with measured path integrals, and (2) has a low third spatial derivative in each direction, at every point. The trade-off between (1) and (2) is controlled by an adjustable parameter, which can be set based on analysis of the path-integral data. The method produces a set of linear equations, which can be solved with a single matrix multiplication if the constraint that all concentrations must be positive is ignored; the method is therefore extremely rapid. Analysis of experimental data from thousands of concentration distributions shows that the method works nearly as well as Smooth Basis Function Minimization (the best method previously available), yet is 100 times faster.

  20. Whole-body magnetic resonance imaging and positron emission tomography-computed tomography in oncology.

    PubMed

    Schmidt, Gerwin P; Kramer, Harald; Reiser, Maximilian F; Glaser, Christian

    2007-06-01

    The advent of positron emission tomography-computed tomography (PET-CT) and whole-body magnetic resonance imaging (WB-MRI) has introduced tumor imaging with a systemic and functional approach compared with established sequential, multimodal diagnostic algorithms.Whole-body PET with [18F]-fluoro-2-desoxy-glucose is a useful imaging procedure for tumor staging and monitoring that can visualize active tumor tissue by detecting pathological glucose metabolism. The combination of PET with the detailed anatomical information of multislice computed tomography as dual-modality scanners has markedly increased lesion localization and diagnostic accuracy compared with both modalities as standalone applications.Hardware innovations, such as the introduction of multi-receiver channel whole-body MRI scanners at 1.5 and, recently, 3 T, combined with acquisition acceleration techniques, have made high-resolution WB-MRI clinically feasible. Now, a dedicated assessment of individual organs with various soft tissue contrast, spatial resolution, and contrast media dynamics can be combined with whole-body anatomical coverage in a multiplanar imaging approach. More flexible protocols (eg, T1-weighted turbo spin-echo and short inversion recovery imaging, dedicated lung imaging or dynamic contrast-enhanced studies of the abdomen) can be performed within 45 minutes.Whole-body magnetic resonance imaging has recently been proposed for tumor screening of asymptomatic individuals, and potentially life-changing diagnoses, such as formerly unknown malignancy, have been reported. However, larger patient cohort studies will have to show the cost efficiency and the clinical effectiveness of such an approach.For initial tumor staging, PET-CT has proved more accurate for the definition of T-stage and lymph node assessment, mainly because of the missing metabolic information in WB-MRI. However, new applications, such as magnetic resonance whole-body diffusion-weighted imaging or lymphotropic contrast agents, may significantly increase sensitivity in near future. Whole-body magnetic resonance imaging has shown advantages for the detection of distant metastatic disease, especially from tumors frequently spreading to the liver or brain and as a whole-body bone marrow screening application. Within this context, WB-MRI is highly accurate for the detection of skeletal metastases and staging of multiple myeloma. This article summarizes recent developments of CT/PET-CT and WB-MRI and highlights their performance within the scope of systemic oncological imaging. PMID:17762383

  1. Statistical interior tomography

    NASA Astrophysics Data System (ADS)

    Xu, Qiong; Yu, Hengyong; Mou, Xuanqin; Wang, Ge

    2010-09-01

    The long-standing interior problem has been recently revisited, leading to promising results on exact local reconstruction also referred to as interior tomography. To date, there are two key computational ingredients of interior tomography. The first ingredient is inversion of the truncated Hilbert transform with prior sub-region knowledge. The second is compressed sensing (CS) assuming a piecewise constant or polynomial region of interest (ROI). Here we propose a statistical approach for interior tomography incorporating the aforementioned two ingredients as well. In our approach, projection data follows the Poisson model, and an image is reconstructed in the maximum a posterior (MAP) framework subject to other interior tomography constraints including known subregion and minimized total variation (TV). A deterministic interior reconstruction based on the inversion of the truncated Hilbert transform is used as the initial image for the statistical interior reconstruction. This algorithm has been extensively evaluated in numerical and animal studies in terms of major image quality indices, radiation dose and machine time. In particular, our encouraging results from a low-contrast Shepp-Logan phantom and a real sheep scan demonstrate the feasibility and merits of our proposed statistical interior tomography approach.

  2. Multiple cystic lymphangiomas of the spleen: radiologic and histopathologic findings.

    PubMed

    Kim, Se-Young; Kwon, Heon-Ju; Park, Hae Won; Lee, So-Yeon; Son, Byung Ho; Kim, Mi Sung

    2015-07-01

    Splenic cyst(s) may be noted as an incidental finding on conventional imaging techniques, or as a result of evaluation of a patient with left upper quadrant pain, left shoulder pain, abdominal enlargement, or splenomegaly. Lymphangioma of the spleen is an extremely rare and benign neoplasm in adults, which is characterized by cystic dilatation of the lymphatic vessels in splenic parenchyma. This report describes a case of multiple splenic lymphangiomas in a 41-year-old female. She underwent abdominal ultrasonography for a health check-up. She had no symptoms, and physical examination did not reveal any abnormalities apart from splenomegaly. Ultrasonography and computed tomography showed multiple variable-sized cysts replacing the normal parenchyma of the spleen. There were wall calcifications in several cysts. The patient underwent laparoscopic splenectomy, and the final diagnosis was multiple lymphangiomas of the spleen. PMID:26576795

  3. Seismic Window Selection and Misfit Measurements for Global Adjoint Tomography

    NASA Astrophysics Data System (ADS)

    Lei, W.; Bozdag, E.; Lefebvre, M.; Podhorszki, N.; Smith, J. A.; Tromp, J.

    2013-12-01

    Global Adjoint Tomography requires fast parallel processing of large datasets. After obtaing the preprocessed observed and synthetic seismograms, we use the open source software packages FLEXWIN (Maggi et al. 2007) to select time windows and MEASURE_ADJ to make measurements. These measurements define adjoint sources for data assimilation. Previous versions of these tools work on a pair of SAC files---observed and synthetic seismic data for the same component and station, and loop over all seismic records associated with one earthquake. Given the large number of stations and earthquakes, the frequent read and write operations create severe I/O bottlenecks on modern computing platforms. We present new versions of these tools utilizing a new seismic data format, namely the Adaptive Seismic Data Format(ASDF). This new format shows superior scalability for applications on high-performance computers and accommodates various types of data, including earthquake, industry and seismic interferometry datasets. ASDF also provides user-friendly APIs, which can be easily integrated into the adjoint tomography workflow and combined with other data processing tools. In addition to solving the I/O bottleneck, we are making several improvements to these tools. For example, FLEXWIN is tuned to select windows for different types of earthquakes. To capture their distinct features, we categorize earthquakes by their depths and frequency bands. Moreover, instead of only picking phases between the first P arrival and the surface-wave arrivals, our aim is to select and assimilate many other later prominent phases in adjoint tomography. For example, in the body-wave band (17 s - 60 s), we include SKS, sSKS and their multiple, while in the surface-wave band (60 s - 120 s) we incorporate major-arc surface waves.

  4. Speckle contrast diffuse correlation tomography of complex turbid medium flow

    PubMed Central

    Huang, Chong; Irwin, Daniel; Lin, Yu; Shang, Yu; He, Lian; Kong, Weikai; Luo, Jia; Yu, Guoqiang

    2015-01-01

    Purpose: Developed herein is a three-dimensional (3D) flow contrast imaging system leveraging advancements in the extension of laser speckle contrast imaging theories to deep tissues along with our recently developed finite-element diffuse correlation tomography (DCT) reconstruction scheme. This technique, termed speckle contrast diffuse correlation tomography (scDCT), enables incorporation of complex optical property heterogeneities and sample boundaries. When combined with a reflectance-based design, this system facilitates a rapid segue into flow contrast imaging of larger, in vivo applications such as humans. Methods: A highly sensitive CCD camera was integrated into a reflectance-based optical system. Four long-coherence laser source positions were coupled to an optical switch for sequencing of tomographic data acquisition providing multiple projections through the sample. This system was investigated through incorporation of liquid and solid tissue-like phantoms exhibiting optical properties and flow characteristics typical of human tissues. Computer simulations were also performed for comparisons. A uniquely encountered smear correction algorithm was employed to correct point-source illumination contributions during image capture with the frame-transfer CCD and reflectance setup. Results: Measurements with scDCT on a homogeneous liquid phantom showed that speckle contrast-based deep flow indices were within 12% of those from standard DCT. Inclusion of a solid phantom submerged below the liquid phantom surface allowed for heterogeneity detection and validation. The heterogeneity was identified successfully by reconstructed 3D flow contrast tomography with scDCT. The heterogeneity center and dimensions and averaged relative flow (within 3%) and localization were in agreement with actuality and computer simulations, respectively. Conclusions: A custom cost-effective CCD-based reflectance 3D flow imaging system demonstrated rapid acquisition of dense boundary data and, with further studies, a high potential for translatability to real tissues with arbitrary boundaries. A requisite correction was also found for measurements in the fashion of scDCT to recover accurate speckle contrast of deep tissues. PMID:26133600

  5. Speckle contrast diffuse correlation tomography of complex turbid medium flow

    SciTech Connect

    Huang, Chong; Irwin, Daniel; Lin, Yu; Shang, Yu; He, Lian; Kong, Weikai; Yu, Guoqiang; Luo, Jia

    2015-07-15

    Purpose: Developed herein is a three-dimensional (3D) flow contrast imaging system leveraging advancements in the extension of laser speckle contrast imaging theories to deep tissues along with our recently developed finite-element diffuse correlation tomography (DCT) reconstruction scheme. This technique, termed speckle contrast diffuse correlation tomography (scDCT), enables incorporation of complex optical property heterogeneities and sample boundaries. When combined with a reflectance-based design, this system facilitates a rapid segue into flow contrast imaging of larger, in vivo applications such as humans. Methods: A highly sensitive CCD camera was integrated into a reflectance-based optical system. Four long-coherence laser source positions were coupled to an optical switch for sequencing of tomographic data acquisition providing multiple projections through the sample. This system was investigated through incorporation of liquid and solid tissue-like phantoms exhibiting optical properties and flow characteristics typical of human tissues. Computer simulations were also performed for comparisons. A uniquely encountered smear correction algorithm was employed to correct point-source illumination contributions during image capture with the frame-transfer CCD and reflectance setup. Results: Measurements with scDCT on a homogeneous liquid phantom showed that speckle contrast-based deep flow indices were within 12% of those from standard DCT. Inclusion of a solid phantom submerged below the liquid phantom surface allowed for heterogeneity detection and validation. The heterogeneity was identified successfully by reconstructed 3D flow contrast tomography with scDCT. The heterogeneity center and dimensions and averaged relative flow (within 3%) and localization were in agreement with actuality and computer simulations, respectively. Conclusions: A custom cost-effective CCD-based reflectance 3D flow imaging system demonstrated rapid acquisition of dense boundary data and, with further studies, a high potential for translatability to real tissues with arbitrary boundaries. A requisite correction was also found for measurements in the fashion of scDCT to recover accurate speckle contrast of deep tissues.

  6. Spectral distortion in diffuse molecular luminescence tomography in turbid media

    NASA Astrophysics Data System (ADS)

    Davis, Scott C.; Pogue, Brian W.; Tuttle, Stephen B.; Dehghani, Hamid; Paulsen, Keith D.

    2009-05-01

    The influence of tissue optical properties on the shape of near-infrared (NIR) fluorescence emission spectra propagating through multiple centimeters of tissue-like media was investigated. Fluorescence emission spectra measured from 6 cm homogeneous tissue-simulating phantoms show dramatic spectral distortion which results in emission peak shifts of up to 60 nm in wavelength. Measured spectral shapes are highly dependent on the photon path length and the scattered photon field in the NIR amplifies the wavelength-dependent absorption of the fluorescence spectra. Simulations of the peak propagation using diffusion modeling describe the experimental observations and confirm the path length dependence of fluorescence emission spectra. Spectral changes are largest for long path length measurements and thus will be most important in human tomography studies in the NIR. Spectrally resolved detection strategies are required to detect and interpret these effects which may otherwise produce erroneous intensity measurements. This observed phenomenon is analogous to beam hardening in x-ray tomography, which can lead to image artifacts without appropriate compensation. The peak shift toward longer wavelengths, and therefore lower energy photons, observed for NIR luminescent signals propagating through tissue may readily be described as a beam softening phenomenon.

  7. Spectral distortion in diffuse molecular luminescence tomography in turbid media.

    PubMed

    Davis, Scott C; Pogue, Brian W; Tuttle, Stephen B; Dehghani, Hamid; Paulsen, Keith D

    2009-05-15

    The influence of tissue optical properties on the shape of near-infrared (NIR) fluorescence emission spectra propagating through multiple centimeters of tissue-like media was investigated. Fluorescence emission spectra measured from 6 cm homogeneous tissue-simulating phantoms show dramatic spectral distortion which results in emission peak shifts of up to 60 nm in wavelength. Measured spectral shapes are highly dependent on the photon path length and the scattered photon field in the NIR amplifies the wavelength-dependent absorption of the fluorescence spectra. Simulations of the peak propagation using diffusion modeling describe the experimental observations and confirm the path length dependence of fluorescence emission spectra. Spectral changes are largest for long path length measurements and thus will be most important in human tomography studies in the NIR. Spectrally resolved detection strategies are required to detect and interpret these effects which may otherwise produce erroneous intensity measurements. This observed phenomenon is analogous to beam hardening in x-ray tomography, which can lead to image artifacts without appropriate compensation. The peak shift toward longer wavelengths, and therefore lower energy photons, observed for NIR luminescent signals propagating through tissue may readily be described as a beam softening phenomenon. PMID:20157444

  8. Excitation-resolved fluorescence tomography with simplified spherical harmonics equations

    NASA Astrophysics Data System (ADS)

    Klose, Alexander D.; Pschinger, Thomas

    2011-03-01

    Fluorescence tomography (FT) reconstructs the three-dimensional (3D) fluorescent reporter probe distribution inside biological tissue. These probes target molecules of biological function, e.g. cell surface receptors or enzymes, and emit fluorescence light upon illumination with an external light source. The fluorescence light is detected on the tissue surface and a source reconstruction algorithm based on the simplified spherical harmonics (SPN) equations calculates the unknown 3D probe distribution inside tissue. While current FT approaches require multiple external sources at a defined wavelength range, the proposed FT method uses only a white light source with tunable wavelength selection for fluorescence stimulation and further exploits the spectral dependence of tissue absorption for the purpose of 3D tomographic reconstruction. We will show the feasibility of the proposed hyperspectral excitation-resolved fluorescence tomography method with experimental data. In addition, we will demonstrate the performance and limitations of such a method under ideal and controlled conditions by means of a digital mouse model and synthetic measurement data. Moreover, we will address issues regarding the required amount of wavelength intervals for fluorescent source reconstruction. We will explore the impact of assumed spatially uniform and nonuniform optical parameter maps on the accuracy of the fluorescence source reconstruction. Last, we propose a spectral re-scaling method for overcoming the observed limitations in reconstructing accurate source distributions in optically non-uniform tissue when assuming only uniform optical property maps for the source reconstruction process.

  9. Poor Uptake of Fluorodeoxyglucose in Positron Emission Tomography-Computed Tomography Scan for Intraocular Choroidal Melanoma in Asian Indian Eyes

    PubMed Central

    Sharma, Rahul S.; Shah, Parag K.; Narendran, Venkatapathy

    2016-01-01

    Fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) scan is fast becoming a very useful tool in diagnosing and staging of several malignancies that affect the human body. We report three cases of ocular choroidal malignant melanoma, wherein FDG PET-CT scan did not show as good uptake as seen in other cancers. PMID:26912980

  10. Magnetic induction tomography

    NASA Astrophysics Data System (ADS)

    Griffiths, H.

    2001-08-01

    Magnetic induction tomography (MIT) is a new imaging modality being developed for the process industry and for medical imaging. MIT applies a magnetic field from an excitation coil to induce eddy currents in the material to be studied, and the magnetic field from these is then detected by sensing coils. The technique has been variously named mutual inductance tomography (also MIT) and electromagnetic tomography (EMT). MIT is sensitive to all three passive electromagnetic properties: conductivity, permittivity and permeability. A number of experimental systems exist but so far no MIT system has reached routine use either industrially or medically. There is a need for the two research communities to work more closely together to further their joint aim in making MIT a successful imaging modality.

  11. 4D Electron Tomography

    NASA Astrophysics Data System (ADS)

    Kwon, Oh-Hoon; Zewail, Ahmed H.

    2010-06-01

    Electron tomography provides three-dimensional (3D) imaging of noncrystalline and crystalline equilibrium structures, as well as elemental volume composition, of materials and biological specimens, including those of viruses and cells. We report the development of 4D electron tomography by integrating the fourth dimension (time resolution) with the 3D spatial resolution obtained from a complete tilt series of 2D projections of an object. The different time frames of tomograms constitute a movie of the object in motion, thus enabling studies of nonequilibrium structures and transient processes. The method was demonstrated using carbon nanotubes of a bracelet-like ring structure for which 4D tomograms display different modes of motion, such as breathing and wiggling, with resonance frequencies up to 30 megahertz. Applications can now make use of the full space-time range with the nanometer-femtosecond resolution of ultrafast electron tomography.

  12. Maximum a posteriori estimator for high-contrast image composition of optical coherence tomography.

    PubMed

    Chan, Aaron C; Kurokawa, Kazuhiro; Makita, Shuichi; Miura, Masahiro; Yasuno, Yoshiaki

    2016-01-15

    A quantitative signal amplitude estimator for optical coherence tomography (OCT) is presented. It is based on a statistical model of OCT signal and noise, using a Bayesian maximum a posteriori (MAP) estimation framework. Multiple OCT images are used for estimation, similar to the widely utilized intensity averaging method. The estimator is less biased especially at low-intensity regions, where intensity averaging approaches the noise power and hence is biased. The estimator is applied to posterior ocular OCT images and provides high-contrast visualization of pathologies. In addition, histogram analysis objectively shows the superior performance of the estimator compared with intensity averaging. PMID:26766704

  13. Parenting Multiples

    MedlinePLUS

    ... Allergy Emergency Cerebral Palsy: Caring for Your Child Parenting Multiples KidsHealth > For Parents > Parenting Multiples Print A ... to take care of your babies. previous continue Parenting Issues With Multiples It can be impossible to ...

  14. Seeing the Unseen—Bioturbation in 4D: Tracing Bioirrigation in Marine Sediment Using Positron Emission Tomography and Computed Tomography

    PubMed Central

    Delefosse, Matthieu; Kristensen, Erik; Crunelle, Diane; Braad, Poul Erik; Dam, Johan Hygum; Thisgaard, Helge; Thomassen, Anders; Høilund-Carlsen, Poul Flemming

    2015-01-01

    Understanding spatial and temporal patterns of bioirrigation induced by benthic fauna ventilation is critical given its significance on benthic nutrient exchange and biogeochemistry in coastal ecosystems. The quantification of this process challenges marine scientists because faunal activities and behaviors are concealed in an opaque sediment matrix. Here, we use a hybrid medical imaging technique, positron emission tomography and computed tomography (PET/CT) to provide a qualitative visual and fully quantitative description of bioirrigation in 4D (space and time). As a study case, we present images of porewater advection induced by the well-studied lugworm (Arenicola marina). Our results show that PET/CT allows more comprehensive studies on ventilation and bioirrigation than possible using techniques traditionally applied in marine ecology. We provide a dynamic three-dimensional description of bioirrigation by the lugworm at very high temporal and spatial resolution. Results obtained with the PET/CT are in agreement with literature data on lugworm ventilation and bioirrigation. Major advantages of PET/CT over methods commonly used are its non-invasive and non-destructive approach and its capacity to provide information that otherwise would require multiple methods. Furthermore, PET/CT scan is versatile as it can be used for a variety of benthic macrofauna species and sediment types and it provides information on burrow morphology or animal behavior. The lack of accessibility to the expensive equipment is its major drawback which can only be overcome through collaboration among several institutions. PMID:25837626

  15. Electron tomography of cells.

    PubMed

    Gan, Lu; Jensen, Grant J

    2012-02-01

    The electron microscope has contributed deep insights into biological structure since its invention nearly 80 years ago. Advances in instrumentation and methodology in recent decades have now enabled electron tomography to become the highest resolution three-dimensional (3D) imaging technique available for unique objects such as cells. Cells can be imaged either plastic-embedded or frozen-hydrated. Then the series of projection images are aligned and back-projected to generate a 3D reconstruction or 'tomogram'. Here, we review how electron tomography has begun to reveal the molecular organization of cells and how the existing and upcoming technologies promise even greater insights into structural cell biology. PMID:22082691

  16. Emission tomography of the kidney

    SciTech Connect

    Teates, C.D.; Croft, B.Y.; Brenbridge, N.A.; Bray, S.T.; Williamson, B.R.

    1983-12-01

    Single photon emission computerized tomography (SPECT) was done on two patients with suspected renal masses. Nuclear scintigraphy was equivocal on two tumors readily identified by SPECT. Single photon tomography is cost effective and increases the reliability of nuclear scintigraphy.

  17. Detection of Widespread Metastasis in a Case of Aggressive Carcinoma Showing Thymuslike Differentiation (CASTLE Disease) Using 18F-FDG PET/CT.

    PubMed

    Iyamu, Ikponmwosa; Wachsmann, Jason; Truelson, John; Mathews, Dana; Peng, Fangyu

    2015-08-01

    A 30-year-old man had a diagnosis of aggressive carcinoma showing thymuslike differentiation (CASTLE disease) and underwent thyroidectomy for tumor resection and bilateral cervical lymph node dissection. Multiple hypermetabolic nodal metastases were detected in the neck and upper mediastinum with fluorine-18-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography ((18)F-FDG PET/CT). The patient received radiation therapy and chemotherapy for treatment of metastases. Follow-up (18)F-FDG PET/CT demonstrated resolution of several hypermetabolic lesions previously seen in the neck, but innumerable new hypermetabolic metastatic lesions were visualized. The patient died of this aggressive CASTLE disease despite treatment with surgery, radiation, and systemic chemotherapy. PMID:25899588

  18. Hamiltonian tomography: the quantum (system) measurement problem

    NASA Astrophysics Data System (ADS)

    Cole, Jared H.

    2015-10-01

    To harness the power of controllable quantum systems for information processing or quantum simulation, it is essential to be able to accurately characterise the system's Hamiltonian. Although in principle this requires determining less parameters than full quantum process tomography, a general and extendable method for reconstructing a general Hamiltonian has been elusive. In their recent paper, Wang et al (2015 New J. Phys. 17 093017) apply dynamical decoupling to the problem of Hamiltonian tomography and show how to reconstruct a general many-body Hamiltonian comprised of arbitrary interactions between qubits.

  19. Supervoltage computed tomography for large aerospace structures

    NASA Astrophysics Data System (ADS)

    Tonner, Paul D.; Stanley, J. H.

    1992-12-01

    A simulation of a 3.9-m solid rocket motor (SRM) with a 12.7-mm steel case, larger than both the Titan and space shuttle SRMs, was used to demonstrate and evaluate the performance of supervoltage computor tomography (SVCT). The attenuation accuracy and the contrast sensitivity of the images are found to be as good as, or better than, those of many lower-energy computer tomography systems. Density profiles through the images do not show any evidence of a cupping artifact. The high quality of the images demonstrates that, with proper design, problems associated with the large dynamic range of the X-ray signal can be effectively solved.

  20. FIB-SEM tomography of human skin telocytes and their extracellular vesicles

    PubMed Central

    Cretoiu, Dragos; Gherghiceanu, Mihaela; Hummel, Eric; Zimmermann, Hans; Simionescu, Olga; Popescu, Laurentiu M

    2015-01-01

    We have shown in 2012 the existence of telocytes (TCs) in human dermis. TCs were described by transmission electron microscopy (TEM) as interstitial cells located in non-epithelial spaces (stroma) of many organs (see www.telocytes.com). TCs have very long prolongations (tens to hundreds micrometers) named Telopodes (Tps). These Tps have a special conformation with dilated portions named podoms (containing mitochondria, endoplasmic reticulum and caveolae) and very thin segments (below resolving power of light microscopy), called podomers. To show the real 3D architecture of TC network, we used the most advanced available electron microscope technology: focused ion beam scanning electron microscopy (FIB-SEM) tomography. Generally, 3D reconstruction of dermal TCs by FIB-SEM tomography revealed the existence of Tps with various conformations: (i) long, flattened irregular veils (ribbon-like segments) with knobs, corresponding to podoms, and (ii) tubular structures (podomers) with uneven calibre because of irregular dilations (knobs) the podoms. FIB-SEM tomography also showed numerous extracellular vesicles (diameter 438.6149.1nm, n=30) released by a human dermal TC. Our data might be useful for understanding the role(s) of TCs in intercellular signalling and communication, as well as for comprehension of pathologies like scleroderma, multiple sclerosis, psoriasis, etc. PMID:25823591

  1. 10. INTERIOR VIEW SHOWING MOUNTINGS FROM TUNING DEVICE. VIEW SHOWS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. INTERIOR VIEW SHOWING MOUNTINGS FROM TUNING DEVICE. VIEW SHOWS COPPER SHEETING ON WALLS. - Chollas Heights Naval Radio Transmitting Facility, Helix House, 6410 Zero Road, San Diego, San Diego County, CA

  2. A Phase Space Tomography Diagnostic for Pitz

    SciTech Connect

    D.J. Holder; B.D. Muratori; F.E. Hannon; S. Khodyachykh; A. Oppelt

    2006-06-26

    The Photo Injector Test Facility at DESY in Zeuthen (PITZ) is a European collaboration developing RF photocathode electron guns for light source and linear collider projects. As part of the collaborative work being partially funded by the EU's FP6 programme, CCLRC Daresbury Laboratory and DESY are designing and building a phase space tomography diagnostic based on a set of multiple quadrupoles and view screens. In order to measure the beam emittance, four screens with intermediate quadrupole doublets will be used. The equipment will be installed and tested at PITZ as part of the facility upgrade presently ongoing. Following simulations of the gun using the ASTRA code at a range of energies, simulations of the electron beam parameters through the matching and tomography sections must be undertaken in order to specify the optimum arrangement of magnets and screens.

  3. 15. Detail showing lower chord pinconnected to vertical member, showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. Detail showing lower chord pin-connected to vertical member, showing floor beam riveted to extension of vertical member below pin-connection, and showing brackets supporting cantilevered sidewalk. View to southwest. - Selby Avenue Bridge, Spanning Short Line Railways track at Selby Avenue between Hamline & Snelling Avenues, Saint Paul, Ramsey County, MN

  4. Gallstone ileus with multiple stones: Where Rigler triad meets Bouveret's syndrome.

    PubMed

    Gaduputi, Vinaya; Tariq, Hassan; Rahnemai-Azar, Amir A; Dev, Anil; Farkas, Daniel T

    2015-12-27

    A 53-year-old man with multiple medical conditions presented to the emergency department with complaints of vomiting, anorexia and diffuse colicky abdominal pain for 3 d. A computed tomography scan of the abdomen and pelvis showed radiographic findings consistent with Rigler triad seen in small proportion of patients with small bowel obstruction secondary to gallstone impaction. In addition there was a gastric outlet obstruction, consistent with Bouveret's syndrome. The patient underwent an exploratory laparotomy and enterotomy with multiple stones extracted. The patient had an uneventful post-surgical clinical course and was discharged home. PMID:26730285

  5. Gallstone ileus with multiple stones: Where Rigler triad meets Bouverets syndrome

    PubMed Central

    Gaduputi, Vinaya; Tariq, Hassan; Rahnemai-Azar, Amir A; Dev, Anil; Farkas, Daniel T

    2015-01-01

    A 53-year-old man with multiple medical conditions presented to the emergency department with complaints of vomiting, anorexia and diffuse colicky abdominal pain for 3 d. A computed tomography scan of the abdomen and pelvis showed radiographic findings consistent with Rigler triad seen in small proportion of patients with small bowel obstruction secondary to gallstone impaction. In addition there was a gastric outlet obstruction, consistent with Bouverets syndrome. The patient underwent an exploratory laparotomy and enterotomy with multiple stones extracted. The patient had an uneventful post-surgical clinical course and was discharged home. PMID:26730285

  6. Single photon emission computed tomography-guided Cerenkov luminescence tomography

    NASA Astrophysics Data System (ADS)

    Hu, Zhenhua; Chen, Xueli; Liang, Jimin; Qu, Xiaochao; Chen, Duofang; Yang, Weidong; Wang, Jing; Cao, Feng; Tian, Jie

    2012-07-01

    Cerenkov luminescence tomography (CLT) has become a valuable tool for preclinical imaging because of its ability of reconstructing the three-dimensional distribution and activity of the radiopharmaceuticals. However, it is still far from a mature technology and suffers from relatively low spatial resolution due to the ill-posed inverse problem for the tomographic reconstruction. In this paper, we presented a single photon emission computed tomography (SPECT)-guided reconstruction method for CLT, in which a priori information of the permissible source region (PSR) from SPECT imaging results was incorporated to effectively reduce the ill-posedness of the inverse reconstruction problem. The performance of the method was first validated with the experimental reconstruction of an adult athymic nude mouse implanted with a Na131I radioactive source and an adult athymic nude mouse received an intravenous tail injection of Na131I. A tissue-mimic phantom based experiment was then conducted to illustrate the ability of the proposed method in resolving double sources. Compared with the traditional PSR strategy in which the PSR was determined by the surface flux distribution, the proposed method obtained much more accurate and encouraging localization and resolution results. Preliminary results showed that the proposed SPECT-guided reconstruction method was insensitive to the regularization methods and ignored the heterogeneity of tissues which can avoid the segmentation procedure of the organs.

  7. Neural networks for calibration tomography

    NASA Technical Reports Server (NTRS)

    Decker, Arthur

    1993-01-01

    Artificial neural networks are suitable for performing pattern-to-pattern calibrations. These calibrations are potentially useful for facilities operations in aeronautics, the control of optical alignment, and the like. Computed tomography is compared with neural net calibration tomography for estimating density from its x-ray transform. X-ray transforms are measured, for example, in diffuse-illumination, holographic interferometry of fluids. Computed tomography and neural net calibration tomography are shown to have comparable performance for a 10 degree viewing cone and 29 interferograms within that cone. The system of tomography discussed is proposed as a relevant test of neural networks and other parallel processors intended for using flow visualization data.

  8. The new cold neutron tomography set-up at SINQ

    NASA Astrophysics Data System (ADS)

    Baechler, S.; Masschaele, B.; Cauwels, P.; Dierick, M.; Jolie, J.; Materna, T.; Mondelaers, W.

    2002-04-01

    A new cold neutron tomography set-up is operational at the neutron spallation source SINQ of the Paul Scherrer Institute (PSI) in Villigen, Switzerland. The detection system is based on a 6LiF/ZnS:Ag conversion screen and a CCD camera. Several tests have been carried out to characterize the quality of the tomography system, such as homogeneity, reproducibility, L/D-ratio and spatial resolution. The high flux and the good efficiency of the detector lead to very short exposure times. Thus, a typical set of tomography scans can be performed in only 20 min. Then, 3D computed tomography objects were calculated using the filtered back-projection reconstruction method. Initial results of various samples show that cold neutron tomography can be a useful tool for industry, geology and dentistry. Furthermore, suitable applications can be found in the field of archeology.

  9. imaging volcanos with gravity and muon tomography measurements

    NASA Astrophysics Data System (ADS)

    Jourde, Kevin; Gibert, Dominique; Marteau, Jacques; Deroussi, Sbastien; Dufour, Fabrice; de Bremond d'Ars, Jean; Ianigro, Jean-Christophe; Gardien, Serge; Girerd, Claude

    2015-04-01

    Both muon tomography and gravimetry are geohysical methods that provide information on the density structure of the Earth's subsurface. Muon tomography measures the natural flux of cosmic muons and its attenuation produced by the screening effect of the rock mass to image. Gravimetry generally consists in measurements of the vertical component of the local gravity field. Both methods are linearly linked to density, but their spatial sensitivity is very different. Muon tomography essentially works like medical X-ray scan and integrates density information along elongated narrow conical volumes while gravimetry measurements are linked to density by a 3-dimensional integral encompassing the whole studied domain. We show that gravity data are almost useless to constrain the density structure in regions sampled by more than two muon tomography acquisitions. Interestingly the resolution in deeper regions not sampled by muon tomography is significantly improved by joining the two techniques. Examples taken from field experiments performed on La Soufrire of Guadeloupe volcano are discussed.

  10. 28. MAP SHOWING LOCATION OF ARVFS FACILITY AS BUILT. SHOWS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. MAP SHOWING LOCATION OF ARVFS FACILITY AS BUILT. SHOWS LINCOLN BOULEVARD, BIG LOST RIVER, AND NAVAL REACTORS FACILITY. F.C. TORKELSON DRAWING NUMBER 842-ARVFS-101-2. DATED OCTOBER 12, 1965. INEL INDEX CODE NUMBER: 075 0101 851 151969. - Idaho National Engineering Laboratory, Advanced Reentry Vehicle Fusing System, Scoville, Butte County, ID

  11. 21 cm Tomography with Foregrounds

    NASA Astrophysics Data System (ADS)

    Wang, Xiaomin; Tegmark, Max; Santos, Mrio G.; Knox, Lloyd

    2006-10-01

    Twenty-one centimeter tomography is emerging as a powerful tool to explore the reionization epoch and cosmological parameters, but it will only be as good as our ability to accurately model and remove astrophysical foreground contamination. Previous treatments of this problem have focused on the angular structure of the signal and foregrounds and what can be achieved with limited spectral resolution (channel widths in the 1 MHz range). In this paper we introduce and evaluate a ``blind'' method to extract the multifrequency 21 cm signal by taking advantage of the smooth frequency structure of the Galactic and extragalactic foregrounds. We find that 21 cm tomography is typically limited by foregrounds on scales of k<<1 h Mpc-1 and is limited by noise on scales of k>>1 h Mpc-1, provided that the experimental channel width can be made substantially smaller than 0.1 MHz. Our results show that this approach is quite promising even for scenarios with rather extreme contamination from point sources and diffuse Galactic emission, which bodes well for upcoming experiments such as LOFAR, MWA, PAST, and SKA.

  12. 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 20 times on a single NVIDIA S1070 GPU, and of 50 times on 4 GPUs, bringing the Jacobian computing time for a fine 3D mesh from 12 minutes to 14 seconds. We regard this as an important step towards gaining interactive reconstruction times in 3D imaging, particularly when coupled in the future with acceleration of the forward problem. While we demonstrate results for Electrical Impedance Tomography, these results apply to any soft-field imaging modality where the Jacobian matrix is computed with the Adjoint Method. PMID:23010857

  13. EDITORIAL: Optical tomography and digital holography

    NASA Astrophysics Data System (ADS)

    Coupland, Jeremy; Lobera, Julia

    2008-07-01

    The articles in this special feature in Measurement Science and Technology concern exciting new developments in the field of digital holographythe process of electronically recording and numerically reconstructing an optical field [1]. Making use of the enormous advances in digital imaging and computer technology, digital holography is presented in a range of applications from fluid flow measurement and structural analysis to medical imaging. The science of digital holography rests on the foundations of optical holography, on the work of Gabor in the late 1940s, and on the development of laser sources in the 1960s, which made his vision a practical reality [2]. Optical holography, however, uses a photosensitive material, both to record a latent image and subsequently to behave as a diffractive optical element with which to reconstruct the incident field. In this way display holograms, using silver halide materials for example, can produce life-size images that are virtually indistinguishable from the object itself [3]. Digital holography, in contrast, separates the steps of recording and reconstruction, and the final image is most often in the form of a 3D computer model. Of course, television cameras have been used from the beginnings of holography to record interferometric images. However, the huge disparity between the resolution of holographic recording materials (more than 3000 cycles/mm) and television cameras (around 50 cycles/mm) was raised as a major concern by early researchers. TV holography, as it was sometimes called, generally recorded low numerical aperture (NA) holograms producing images with characteristically large speckle and was therefore more often referred to as electronic speckle pattern interferomery (ESPI) [4]. It is possible, however, to record large NA holograms on a sensor with restricted resolution by using an objective lens or a diverging reference wave [5]. This is generally referred to as digital holographic microscopy (DHM) since the resolution now places a limit on the size of the object that can be recorded. Some 60 years after the pioneering work of Gabor, digital imaging and associated computer technology offers a step change in capability with which to further exploit holography. Modern image sensors are now available with almost 30 million photosensitive elements, which corresponds to a staggering 100-fold increase compared to standard television images. At the same time personal computers have been optimized for imaging and graphics applications and this allows more sophisticated algorithms to be used in the reconstruction process. Although resolution still falls short of the materials used for optical holography, the ability to process data numerically generally outweighs this drawback and presents us with a host of new opportunities. Faced with the ability to record and process holograms numerically, it is natural to ask the question 'what information is present within recordings of scattered light?'. In fact this question could be posed by anyone using light, or indeed any other wave disturbance, for measurement purposes. For the case of optical holography, Wolf published his answer in 1969 [6], showing that for the case of weak scattering (small perturbations) and plane wave illumination, the amplitude and phase of each plane wave within the scattered field are proportional to those of a periodic variation in the refractive index contrast (i.e. a Bragg grating). This Fourier decomposition of the object was published almost simultaneously by Dandliker and Weiss [7], who also provided a graphical illustration of the technique. These works are the basis of optical tomography and provide us with the link between holographic data and 3D form. Digital holographic reconstruction and optical tomography was the theme of an international workshop [8] held in Loughborough in 2007, and many of the topics debated at the workshop have become the subject of the papers in this issue. In general terms the papers we present describe closely related holographic techniques that address application areas within the field of engineering. The application of digital holography to 3D fluid flow measurement is addressed by several authors. Salah et al demonstrate the simplicity of digital holography with an in-line multiple exposure holographic system using a low-cost laser diode. Soria and Atkinson discuss limitations of low NA holography in fluid velocimetry and demonstrate the potential of a multiple camera, in-line technique which they call Tomographic Digital Holographic Particle Image Velocimetry (Tomo-HPIV). Problems caused by the twin images (real and virtual) of in-line HPIV are described by Ooms et al. It is shown how sign ambiguity can be eliminated and bias errors suppressed by the application of a suitable threshold in piecewise correlation of the reconstructed field. Denis et al explain the problem of twin image removal as a deconvolution process and compare suppression algorithms based on wavelet decomposition. This process can be considered as an inverse problem and the benefits of this approach are discussed with reference to particulate holograms by Gire et al. Of course, the twin image problem can be solved by off-axis holographic geometries which, in effect, add a carrier modulation. Arroyo presents a comparison of carrier modulation strategies that have been presented in the literature and shows circumstances in which the information in each of the real and virtual images can be separated when the sensor resolution is less than that required by the NA of the objective. State-of-the-art digital holographic microscopy (DHM) is presented by Khn et al. This paper uses an off-axis geometry that simultaneously records images at two wavelengths. The microscope allows the surface profile to be measured from a single recording and sub-nanometre axial resolution is demonstrated. Another interesting application of DHM is addressed by Grilli et al. They report a transmission set-up to investigate poling in a lithium niobate crystal. Developments in the field of optical tomography are covered by the majority of the papers in this issue. The paper by Debailleul et al shows the differences between images reconstructed from a single holographic recording and those synthesized from a series of holograms made with different plane wave illumination. This is optical diffraction tomography (ODT), the original method discussed by Wolf that is characterized by large NA and monochromatic illumination. An alternative strategy is to synthesize the image from holograms made at several wavelengths with low NA optics. This can be done either by sweeping the source or detector response or the reference path in a white light interferometer. These methods are called spectral domain and temporal domain optical coherence tomography (SD-ODT and TD-OCT) respectively. SD-OCT is illustrated in the paper by Potcoava and Kim for biomedical applications. SD- and TD-OCT are compared with confocal microscopy in the paper by Stifter et al. The huge potential of OCT as a diagnostic in polymer and composite materials is apparent from this work. There are clearly many different ways to implement optical tomography, and several established techniques, such as scanning white light interferometry (SWLI) and confocal microscopy, can be considered to be tomographic processes. We present two papers in this issue. The first attempts to bring together the topics of holography, microscopy and tomography within the framework of linear systems theory. It is shown that the images (or interferograms) produced by these instruments can be considered as estimates of refractive index contrast that are obtained using a linear inversion of the scattered field data. It is noted, however, that this is only strictly correct for the case of weak scattering and this is only a crude approximation for many cases of practical interest. The second paper that we present illustrates this for the case of mono-disperse particles in air. Here the number density of the particles is such that multiple scattering is prevalent; however, a priori knowledge of particle size and refractive index allows individual particles to be located accurately. In general, reconstruction can be thought of as a nonlinear optimization process that is used to discover the object which best explains the measured field and is consistent with a priori information. As Gire et al point out in their article, a priori knowledge can also be used to overcome the Nyquist sampling criteria. Although some caution should be exercised (for example, it is not usually possible to decide whether a given solution is unique), it is interesting to note that despite the disparity in resolution, digital holography and computer technology might yet create 3D images of greater clarity than the best optical holograms. References [1] Schnars U and Jueptner W 2005 Digital Holography (Berlin: Springer) ISBN: 978 3 540 21934 7 [2] Gabor D 1948 A new microscopic principle Nature 161 777-8 [3] Bjelkhagen H I 1993 Silver-Halide Recording Materials (Berlin: Springer) ISBN 3 540 58619 9 [4] Leendertz J A 1970 Interferometric displacement measurement on scattering surfaces utilizing speckle effect J. Phys. E: Sci. Instrum. 3 214-8 [5] Marquet P, Rappaz B, Magistretti P J, Cuche E, Emery Y, Colomb T and Depeursinge C 2005 Digital holographic microscopy: a noninvasive contrast imaging technique allowing quantitative visualization of living cells with subwavelength axial accuracy Opt. Lett. 30 468-70 [6] Wolf E 1969 Three-dimensional structure determination of semi-transparent objects from holographic data Opt. Commun. 1 153-6 [7] Dandliker R and Weiss K 1970 Reconstruction of the three-dimensional refractive index from scattered waves Opt. Commun. 1 323-8 [8] Coupland J and Lobera J 2007 International Workshop on Digital Holographic Reconstruction and Optical Tomography for Engineering Applications ISBN 978 0 947974 56 5

  14. Multiple Books, Multiple Authors.

    ERIC Educational Resources Information Center

    Kountz, Carol

    When a class of lethargic college students showed no enthusiasm for their reading assignments in English class, one instructor turned to drama. She assigned a collaborative script, and the students' enthusiasm and motivation relegated her to a "pleasant oblivion." She thought that the novelty of the play genre might enliven the class, and she had…

  15. Optical Coherence Tomography

    NASA Astrophysics Data System (ADS)

    Faber, Dirk J.; van Leeuwen, Ton G.

    Seventy percent of our body is made up of water. For that reason, radiation based medical imaging techniques operate in spectral regions where water absorption is low (Fig. 18.1, panel). Well known modalities are MRI that operates at radio frequencies, and PET/SPECT which work in the high frequency range. Water absorption is also low around the part of the spectrum that is visible to the human eye. In this spectral region, scattering of the light by tissue structures roughly decreases with wavelength. Therefore, most optical imaging techniques such as (confocal) microscopy, optical tomography and Optical Coherence Tomography (OCT) use wavelengths between 650 and 1300 nm to allow reasonable imaging depths.

  16. Quantitative dynamic SPECT tomography

    SciTech Connect

    Haber, E.; Oldenburg, D.; Farnocombe, T.; Celler, A.

    1996-12-31

    Single Photon Emission Tomography (SPECT) and Positron Emission Tomograph (PET) are two methods in which functional information is obtained. This information is obtained by reconstructing the distribution of tracers. Since the tracer is designed to target specific physiological activity, its distribution contains the information about which areas are physiologically active and which are not. Regular reconstruction methods do not indicate how the activity changes in time. This is the goal of dynamic studies. Dynamic SPECT or PET tomography is the study of the kinetics of a tracer, i.e. how does the tracers` distribution changes in time. Modelling of such behavior suggests that it is an exponentially decaying process that can be characterized with a few exponentials.

  17. Finite element Compton tomography

    NASA Astrophysics Data System (ADS)

    Jannson, Tomasz; Amouzou, Pauline; Menon, Naresh; Gertsenshteyn, Michael

    2007-09-01

    In this paper a new approach to 3D Compton imaging is presented, based on a kind of finite element (FE) analysis. A window for X-ray incoherent scattering (or Compton scattering) attenuation coefficients is identified for breast cancer diagnosis, for hard X-ray photon energy of 100-300 keV. The point-by-point power/energy budget is computed, based on a 2D array of X-ray pencil beams, scanned vertically. The acceptable medical doses are also computed. The proposed finite element tomography (FET) can be an alternative to X-ray mammography, tomography, and tomosynthesis. In experiments, 100 keV (on average) X-ray photons are applied, and a new type of pencil beam collimation, based on a Lobster-Eye Lens (LEL), is proposed.

  18. Controllable tomography phase microscopy

    NASA Astrophysics Data System (ADS)

    Xiu, Peng; Zhou, Xin; Kuang, Cuifang; Xu, Yingke; Liu, Xu

    2015-03-01

    Tomography phase microscopy (TPM) is a new microscopic method that can quantitatively yield the volumetric 3D distribution of a sample's refractive index (RI), which is significant for cell biology research. In this paper, a controllable TPM system is introduced. In this system a circulatory phase-shifting method and piezoelectric ceramic are used which enable the TPM system to record the 3D RI distribution at a more controllable speed, from 1 to 40 fps, than in the other TPM systems reported. The resolution of the RI distribution obtained by this controllable TPM is much better than that in images recorded by phase contrast microscopy and interference tomography microscopy. The realization of controllable TPM not only allows for the application of TPM to the measurement of kinds of RI sample, but also contributes to academic and technological support for the practical use of TPM.

  19. 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.

  20. Experimental adaptive Bayesian tomography

    NASA Astrophysics Data System (ADS)

    Kravtsov, K. S.; Straupe, S. S.; Radchenko, I. V.; Houlsby, N. M. T.; Huszár, F.; Kulik, S. P.

    2013-06-01

    We report an experimental realization of an adaptive quantum state tomography protocol. Our method takes advantage of a Bayesian approach to statistical inference and is naturally tailored for adaptive strategies. For pure states, we observe close to N-1 scaling of infidelity with overall number of registered events, while the best nonadaptive protocols allow for N-1/2 scaling only. Experiments are performed for polarization qubits, but the approach is readily adapted to any dimension.

  1. 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.

  2. Primary central nervous system lymphoma in an human immunodeficiency virus-infected patient mimicking bilateral eye sign in brain seen in fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusany; Thirugnanam, Rajasekar; Shibu, Deepu; Kalarikal, Radhakrishnan Edathurthy; Shinto, Ajit Sugunan

    2014-01-01

    Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG PET/CT) has proven useful in the diagnosis, staging, and detection of metastasis and posttreatment monitoring of several malignancies in human immunodeficiency virus (HIV)-infected patients. It also has the ability to make the important distinction between malignancy and infection in the evaluation of central nervous system (CNS) lesions, leading to the initiation of the appropriate treatment and precluding the need for invasive biopsy. We report an interesting case of HIV positive 35-year-old woman presented with headache, disorientation, and decreased level of consciousness. She underwent whole body PET/CT which showed multiple lesions in the cerebrum which mimics bilateral eye in brain. A diagnosis of a primary CNS lymphoma was made and patient was started on chemotherapy. PMID:24761060

  3. Primary central nervous system lymphoma in an human immunodeficiency virus-infected patient mimicking bilateral eye sign in brain seen in fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusany; Thirugnanam, Rajasekar; Shibu, Deepu; Kalarikal, Radhakrishnan Edathurthy; Shinto, Ajit Sugunan

    2014-04-01

    Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG PET/CT) has proven useful in the diagnosis, staging, and detection of metastasis and posttreatment monitoring of several malignancies in human immunodeficiency virus (HIV)-infected patients. It also has the ability to make the important distinction between malignancy and infection in the evaluation of central nervous system (CNS) lesions, leading to the initiation of the appropriate treatment and precluding the need for invasive biopsy. We report an interesting case of HIV positive 35-year-old woman presented with headache, disorientation, and decreased level of consciousness. She underwent whole body PET/CT which showed multiple lesions in the cerebrum which mimics bilateral eye in brain. A diagnosis of a primary CNS lymphoma was made and patient was started on chemotherapy. PMID:24761060

  4. Ionospheric tomography using the FORTE satellite

    SciTech Connect

    Murphy, T.C.

    1993-08-01

    The possibility of obtaining ionospheric profile data via tomographic techniques has elicited considerable interest in recent years. The input data for the method is a set of total electron content measurements along intersecting lines of sight which form a grid. This can conveniently be provided by a fast-moving satellite with a VHF beacon which will generate the multiple paths needed for effective tomography. Los Alamos and Sandia National Laboratories will launch and operate the FORTE satellite for the US Department of Energy, with launch scheduled in 1995. FORTE will provide such a beacon. Additionally, wideband VHF receivers aboard the satellite will allow corraborative measurements of ionospheric profile parameters in some cases.

  5. Multiple Sclerosis

    MedlinePLUS

    Multiple sclerosis (MS) is a nervous system disease that affects your brain and spinal cord. It damages the ... attacks healthy cells in your body by mistake. Multiple sclerosis affects women more than men. It often begins ...

  6. Source Reconstruction for Spectrally-resolved Bioluminescence Tomography with Sparse A priori Information

    PubMed Central

    Lu, Yujie; Zhang, Xiaoqun; Douraghy, Ali; Stout, David; Tian, Jie; Chan, Tony F.; Chatziioannou, Arion F.

    2009-01-01

    Through restoration of the light source information in small animals in vivo, optical molecular imaging, such as fluorescence molecular tomography (FMT) and bioluminescence tomography (BLT), can depict biological and physiological changes observed using molecular probes. A priori information plays an indispensable role in tomographic reconstruction. As a type of a priori information, the sparsity characteristic of the light source has not been sufficiently considered to date. In this paper, we introduce a compressed sensing method to develop a new tomographic algorithm for spectrally-resolved bioluminescence tomography. This method uses the nature of the source sparsity to improve the reconstruction quality with a regularization implementation. Based on verification of the inverse crime, the proposed algorithm is validated with Monte Carlo-based synthetic data and the popular Tikhonov regularization method. Testing with different noise levels and single/multiple source settings at different depths demonstrates the improved performance of this algorithm. Experimental reconstruction with a mouse-shaped phantom further shows the potential of the proposed algorithm. PMID:19434138

  7. Polychromatic diffraction contrast tomography

    SciTech Connect

    King, A.; Reischig, P.; Adrien, J.; Peetermans, S.; Ludwig, W.

    2014-11-15

    This tutorial review introduces the use of polychromatic radiation for 3D grain mapping using X-ray diffraction contrast tomography. The objective is to produce a 3D map of the grain shapes and orientations within a bulk, millimeter-sized polycrystalline sample. The use of polychromatic radiation enables the standard synchrotron X-ray technique to be applied in a wider range of contexts: 1) Using laboratory X-ray sources allows a much wider application of the diffraction contrast tomography technique. 2) Neutron sources allow large samples, or samples containing high Z elements to be studied. 3) Applied to synchrotron sources, smaller samples may be treated, or faster measurements may be possible. Challenges and particularities in the data acquisition and processing, and the limitations of the different variants, are discussed. - Highlights: • We present a tutorial review of polychromatic diffraction contrast tomography techniques. • The use of polychromatic radiation allows the standard synchrotron DCT technique to be extended to a range of other sources. • The characteristics and limitations of all variants of the techniques are derived, discussed and compared. • Examples using laboratory X-ray and cold neutron radiation are presented. • Suggestions for the future development of these techniques are presented.

  8. Generalized local emission tomography

    DOEpatents

    Katsevich, Alexander J.

    1998-01-01

    Emission tomography enables locations and values of internal isotope density distributions to be determined from radiation emitted from the whole object. In the method for locating the values of discontinuities, the intensities of radiation emitted from either the whole object or a region of the object containing the discontinuities are inputted to a local tomography function .function..sub..LAMBDA..sup.(.PHI.) to define the location S of the isotope density discontinuity. The asymptotic behavior of .function..sub..LAMBDA..sup.(.PHI.) is determined in a neighborhood of S, and the value for the discontinuity is estimated from the asymptotic behavior of .function..sub..LAMBDA..sup.(.PHI.) knowing pointwise values of the attenuation coefficient within the object. In the method for determining the location of the discontinuity, the intensities of radiation emitted from an object are inputted to a local tomography function .function..sub..LAMBDA..sup.(.PHI.) to define the location S of the density discontinuity and the location .GAMMA. of the attenuation coefficient discontinuity. Pointwise values of the attenuation coefficient within the object need not be known in this case.

  9. Enhanced local tomography

    DOEpatents

    Katsevich, Alexander J.; Ramm, Alexander G.

    1996-01-01

    Local tomography is enhanced to determine the location and value of a discontinuity between a first internal density of an object and a second density of a region within the object. A beam of radiation is directed in a predetermined pattern through the region of the object containing the discontinuity. Relative attenuation data of the beam is determined within the predetermined pattern having a first data component that includes attenuation data through the region. In a first method for evaluating the value of the discontinuity, the relative attenuation data is inputted to a local tomography function .function..sub..LAMBDA. to define the location S of the density discontinuity. The asymptotic behavior of .function..sub..LAMBDA. is determined in a neighborhood of S, and the value for the discontinuity is estimated from the asymptotic behavior of .function..sub..LAMBDA.. In a second method for evaluating the value of the discontinuity, a gradient value for a mollified local tomography function .gradient..function..sub..LAMBDA..epsilon. (x.sub.ij) is determined along the discontinuity; and the value of the jump of the density across the discontinuity curve (or surface) S is estimated from the gradient values.

  10. Ocean acoustic reverberation tomography.

    PubMed

    Dunn, Robert A

    2015-12-01

    Seismic wide-angle imaging using ship-towed acoustic sources and networks of ocean bottom seismographs is a common technique for exploring earth structure beneath the oceans. In these studies, the recorded data are dominated by acoustic waves propagating as reverberations in the water column. For surveys with a small receiver spacing (e.g., <10 km), the acoustic wave field densely samples properties of the water column over the width of the receiver array. A method, referred to as ocean acoustic reverberation tomography, is developed that uses the travel times of direct and reflected waves to image ocean acoustic structure. Reverberation tomography offers an alternative approach for determining the structure of the oceans and advancing the understanding of ocean heat content and mixing processes. The technique has the potential for revealing small-scale ocean thermal structure over the entire vertical height of the water column and along long survey profiles or across three-dimensional volumes of the ocean. For realistic experimental geometries and data noise levels, the method can produce images of ocean sound speed on a smaller scale than traditional acoustic tomography. PMID:26723303

  11. Planning a Successful Tech Show

    ERIC Educational Resources Information Center

    Nikirk, Martin

    2011-01-01

    Tech shows are a great way to introduce prospective students, parents, and local business and industry to a technology and engineering or career and technical education program. In addition to showcasing instructional programs, a tech show allows students to demonstrate their professionalism and skills, practice public presentations, and interact…

  12. Hey Teacher, Your Personality's Showing!

    ERIC Educational Resources Information Center

    Paulsen, James R.

    1977-01-01

    A study of 30 fourth, fifth, and sixth grade teachers and 300 of their students showed that a teacher's age, sex, and years of experience did not relate to students' mathematics achievement, but that more effective teachers showed greater "freedom from defensive behavior" than did less effective teachers. (DT)

  13. Planning a Successful Tech Show

    ERIC Educational Resources Information Center

    Nikirk, Martin

    2011-01-01

    Tech shows are a great way to introduce prospective students, parents, and local business and industry to a technology and engineering or career and technical education program. In addition to showcasing instructional programs, a tech show allows students to demonstrate their professionalism and skills, practice public presentations, and interact

  14. Multiple Myeloma

    MedlinePLUS

    MENU Return to Web version Multiple Myeloma Overview What is multiple myeloma? Multiple myeloma (say: my-a-low-ma) is a kind of ... greater risk due to exposure to chemicals. Diagnosis & Tests How does my doctor know if I have ...

  15. Finger Multiplication

    ERIC Educational Resources Information Center

    Simanihuruk, Mudin

    2011-01-01

    Multiplication facts are difficult to teach. Therefore many researchers have put a great deal of effort into finding multiplication strategies. Sherin and Fuson (2005) provided a good survey paper on the multiplication strategies research area. Kolpas (2002), Rendtorff (1908), Dabell (2001), Musser (1966) and Markarian (2009) proposed the finger

  16. F-18 fluoro-d-glucose positron emission tomography/computed tomography in a patient with corticobasal degeneration.

    PubMed

    Marti, Alejandro

    2015-01-01

    Corticobasal degeneration is a rare neurodegenerative disorder that often eludes clinical diagnosis. The present case shows the F-18 fluoro-d-glucose positron emission tomography/computed tomography (PET/CT) of a 62-year-old man with a progressive movement disorder with asymmetric features. PET/CT examination showed a markedly right-brain hemispheric hypometabolism also involving basal ganglia. PMID:25829747

  17. Utility of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography in a child with chronic granulomatous disease

    PubMed Central

    Garg, Gunjan; DaSilva, Raphaella; Bhalakia, Avni; Milstein, David M.

    2016-01-01

    We report the fluorodeoxyglucose positron emission tomography/computed tomography (FDG - PET/CT) findings in an 11-month-old boy with suspected milk protein allergy, presented to the hospital with 2-month history of fever of unknown origin and failure to thrive. It showed FDG avid lymphadenopathy above and below the diaphragm and splenic focus, which could represent diffuse inflammatory process or lymphoma. Subsequent jejunal biopsy showed non-necrotizing granulomas. PMID:26917900

  18. [The history of tomography].

    PubMed

    Seynaeve, P C; Broos, J I

    1995-10-01

    It is easily forgotten that not yet a hundred years ago the only way to look into the patients' body was via invasive procedures. Within the year of the discovery of X-rays by Conrad Rntgen the need for three dimensional imaging had been voiced. The driving force behind this development was undoubtedly clinical motivation. Planar X-radiographs were not satisfactory to the clinicians who urged the radiologists to provide them with tomographic images. Between 1910 and 1940, classical tomography has been the product of individuals rather than collective groups. It is only in the mid thirties that scientists found out about each other and started to correspond vigorously. Mayer was the first to suggest in 1914 the idea of tomography. Bocage, Grossman and Vallebona all developed the idea further and built their own equipment. In 1931 Ziedses des Plantes published the most extensive and thorough study on tomography. In the forties and fifties a stagnation is noticed, only further refinements to the existing equipment are carried out. Although Frank and Takahashi published the basic principles of axial tomography in the mid forties, we had to wait for the necessary developments in electronics before Hounsfield was able to develop and commercialize the first axial computer tomography in 1972 (EMI-Scanner). At the time all the big radiology companies rushed into the field and soon, second, third and fourth generation CT scanners became available. Only a few years later a new way of generating images without using ionizing radiation was introduced. Lauterbur and Damadian produced the first low quality images with magnetic resonance, a technique called zeugmatography by its inventors. In 1974 the first images of a living subject were published and initial scepticism was replaced by euphoria. This resulted in the spectacular evolution in Magnetic Resonance that we are now observing. While it is impossible to predict the future, the development of networks, the increase in data acquisition and storage will spread a new light on our specialty. A closer cooperation between radiologists, pathologists and clinicians will undoubtedly be necessary, as well as a partial redefinition of the radiologists task. PMID:8550391

  19. Optical Coherence Tomography of the Newborn Airway

    PubMed Central

    Ridgway, James M.; Su, Jianping; Wright, Ryan; Guo, Shuguang; Kim, David C.; Barretto, Roberto; Ahuja, Gurpreet; Sepehr, Ali; Perez, Jorge; Sills, Jack H.; Chen, Zhongping; Wong, Brian J. F.

    2010-01-01

    Objectives Acquired subglottic stenosis in a newborn is often associated with prolonged endotracheal intubation. This condition is generally diagnosed during operative endoscopy after airway injury has occurred. Unfortunately, endoscopy is unable to characterize the submucosal changes observed in such airway injuries. Other modalities, such as magnetic resonance imaging, computed tomography, and ultrasound, do not possess the necessary level of resolution to differentiate scar, neocartilage, and edema. Optical coherence tomography (OCT) is an imaging modality that produces high-resolution, cross-sectional images of living tissue (8 to 20 µm). We examined the ability of this noninvasive technique to characterize the newborn airway in a prospective clinical trial. Methods Twelve newborn patients who required ventilatory support underwent OCT airway imaging. Comparative analysis of intubated and non-intubated states was performed. Results Imaging of the supraglottis, glottis, subglottis, and trachea was performed in 12 patients, revealing unique tissue characteristics as related to turbidity, signal backscattering, and architecture. Multiple structures were identified, including the vocal folds, cricoid cartilage, tracheal rings, ducts, glands, and vessels. Conclusions Optical coherence tomography clearly identifies in vivo tissue layers and regional architecture while offering detailed information concerning tissue microstructures. The diagnostic potential of this technology makes OCT a promising modality in the study and surveillance of the neonatal airway. PMID:18564528

  20. TRK Inhibitor Shows Early Promise.

    PubMed

    2016-01-01

    Results from a phase I study show that the TRK inhibitor LOXO-101 is well tolerated and effective, with patients whose tumors bear NTRK fusions responding well and durably to this targeted therapy. PMID:26603524

  1. Multiplicity Counting

    SciTech Connect

    Geist, William H.

    2015-12-01

    This set of slides begins by giving background and a review of neutron counting; three attributes of a verification item are discussed: 240Pueff mass; α, the ratio of (α,n) neutrons to spontaneous fission neutrons; and leakage multiplication. It then takes up neutron detector systems – theory & concepts (coincidence counting, moderation, die-away time); detector systems – some important details (deadtime, corrections); introduction to multiplicity counting; multiplicity electronics and example distributions; singles, doubles, and triples from measured multiplicity distributions; and the point model: multiplicity mathematics.

  2. Ionospheric imaging using computerized tomography

    SciTech Connect

    Austen, J.R.

    1991-01-01

    Computerized tomography (CT) techniques can be used to produce a two-dimensional image of the electron density in the ionosphere. The necessary data are transionospheric satellite beacon total electron content (TEC) data recorded simultaneously at multiple ground stations. The ionospheric imaging case presents a difficult problem due to large amounts of missing data. This is a consequence of the locations of the transmitter (in orbit) and receivers (ground-based) and causes the reconstruction algorithm to fail to correctly reconstruct the background density profile. Despite this limitation, a method has been developed which successfully reconstructs the irregularities and variations in the profile. A computer program simulates the data collection and image reconstruction process. This allows the method to be tested with several electron density models, transmitter and receiver locations, and noniterative and iterative reconstruction algorithms. Simulations are performed assuming a 1,000-km-altitude polar-orbiting satellite and several ground stations. The imaged region is 3,500 km wide by 800 km high. A new algorithm, which is a modification of the discrete backprojection algorithm, is developed for use with nonuniform sampling geometries.

  3. Multimodal optical imaging with multiphoton microscopy and optical coherence tomography.

    PubMed

    Tang, Shuo; Zhou, Yifeng; Ju, Myeong Jin

    2012-05-01

    Two types of combined multiphoton microscopy and optical coherence tomography (MPM/OCT) are compared for multimodal optical imaging. Single-scale multiphoton microscopy and optical coherence microscopy (MPM/OCM) is shown to acquire multiple contrasts from MPM and OCT simultaneously. Multi-scale MPM/OCT is shown to provide multiple field-of-views (FOVs), where OCT provides tissue level imaging and MPM provides cellular level imaging. In both types, the MPM includes two channels which are two-photon excited fluorescence (TPEF) and second harmonic generation (SHG). Representative images using each system are demonstrated on biological specimens. A detailed comparison of the two types of MPM/OCT shows that each system has its own pros and cons. MPM/OCM is high-resolution but with limited FOV, and OCM may or may not provide additional information than MPM depending on the samples. Multi-scale MPM/OCT can change FOV but need both low and high NA objectives. For future development, the two types of MPM/OCT can be further integrated to achieve both functions on a single system. PMID:22461146

  4. Vertebral sarcoidosis: demonstration of bone involvement by computerized axial tomography

    SciTech Connect

    Dinerstein, S.L.; Kovarsky, J.

    1984-08-01

    A report is given of a rare case of vertebral sarcoidosis with negative conventional spinal x-ray films, yet with typical cystic lesions of the spine found incidentally during abdominal computerized axial tomography (CAT). The patient was a 28-year-old black man, who was admitted for evaluation of a 1 1/2-year history of diffuse myalgias, intermittent fever to 102 F orally, bilateral hilar adenopathy, and leukopenia. A technetium polyphosphate bone scan revealed diffuse areas of increased uptake over the sternum, entire vertebral column, and pelvis. Conventional x-ray films of the cervical, thoracic, and lumbar spine, and an AP view of the pelvis were all normal. Chest x-ray film revealed only bilateral hilar adenopathy. During the course of an extensive negative evaluation for infection, an abdominal CAT scan was done, showing multiple, small, sclerotic-rimmed cysts at multiple levels of the lower thoracic and lumbar spine. Bone marrow biopsy revealed only changes consistent with anemia of chronic disease. Mediastinal lymph node biopsy revealed noncaseating granulomas. A tentative diagnosis of sarcoidosis was made, and treatment with prednisone, isoniazid and rifampin was begun. Within two weeks of initiation of prednisone therapy, the patient was symptom-free. A repeat technetium polyphosphate bone scan revealed only a small residual area of mildly increased uptake over the upper thoracic vertebrae.

  5. Experimental Results of Guided Wave Travel Time Tomography

    NASA Astrophysics Data System (ADS)

    Volker, Arno; Mast, Arjan; Bloom, Joost

    2010-02-01

    Corrosion is one of the industries major issues regarding the integrity of assets. Currently inspections are conducted at regular intervals to ensure a sufficient integrity level of these assets. Both economical and social requirements are pushing the industry to even higher levels of availability, reliability and safety of installations. The concept of predictive maintenance using permanent sensors that monitor the integrity of an installation is an interesting addition to the current method of periodic inspections reducing uncertainty and extending inspection intervals. Guided wave travel time tomography is a promising method to monitor the wall thickness quantitatively over large areas. Obviously the robustness and reliability of such a monitoring system is of paramount importance. Laboratory experiments have been carried out on a 10? pipe with a nominal wall thickness of 8 mm. Multiple, inline defects have been created with a realistic morphology. The depth of the defects was increased stepwise from 0.5 mm to 2 mm. Additionally the influences of the presence of liquid inside the pipe and surface roughness have been evaluated as well. Experimental results show that this method is capable of providing quantitative wall thickness information over a distance of 4 meter, with a sufficient accuracy such that results can be used for trending. The method has no problems imaging multiple defects.

  6. Electrical Impedance Tomography of Electrolysis

    PubMed Central

    Meir, Arie; Rubinsky, Boris

    2015-01-01

    The primary goal of this study is to explore the hypothesis that changes in pH during electrolysis can be detected with Electrical Impedance Tomography (EIT). The study has relevance to real time control of minimally invasive surgery with electrolytic ablation. To investigate the hypothesis, we compare EIT reconstructed images to optical images acquired using pH-sensitive dyes embedded in a physiological saline agar gel phantom treated with electrolysis. We further demonstrate the biological relevance of our work using a bacterial E.Coli model, grown on the phantom. The results demonstrate the ability of EIT to image pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E.coli model. The results are promising, and invite further experimental explorations. PMID:26039686

  7. Photoacoustic tomography: principles and advances

    PubMed Central

    Xia, Jun; Yao, Junjie; Wang, Lihong V.

    2014-01-01

    Photoacoustic tomography (PAT) is an emerging imaging modality that shows great potential for preclinical research and clinical practice. As a hybrid technique, PAT is based on the acoustic detection of optical absorption from either endogenous chromophores, such as oxy-hemoglobin and deoxy-hemoglobin, or exogenous contrast agents, such as organic dyes and nanoparticles. Because ultrasound scatters much less than light in tissue, PAT generates high-resolution images in both the optical ballistic and diffusive regimes. Over the past decade, the photoacoustic technique has been evolving rapidly, leading to a variety of exciting discoveries and applications. This review covers the basic principles of PAT and its different implementations. Strengths of PAT are highlighted, along with the most recent imaging results. PMID:25642127

  8. rf testbed for thermoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Fallon, D.; Yan, L.; Hanson, G. W.; Patch, S. K.

    2009-06-01

    Thermoacoustic signal excitation is a function of intrinsic tissue properties and illuminating electric field. De-ionized (DI) water is a preferred acoustic coupling medium for thermoacoustics because acoustic and electromagnetic waves propagate in DI water with very little loss. We have designed a water-filled testbed propagating a controlled electric field with respect to pulse shape, power, and polarization. Directional coupler line sections permit measurement of incident, reflected, and transmitted powers. Both S-parameters and Ey measurement show that the electric-field distribution is relatively uniform in testbed. Comparing baseline power measurements to those taken with a test object in place yields power loss in the object, which should correlate to thermoacoustic signal strength. Moreover, power loss—and therefore thermoacoustic computerized tomography signal strength—is sensitive to the orientation of the object to the polarization of the electric field. This testbed will enable quantitative characterization of the thermoacoustic contrast mechanism in ex vivo tissue specimens.

  9. [A Case of Cecal Cancer with Multiple Cutaneous Metastases].

    PubMed

    Komoto, Masahiro; Tanaka, Ryota; Kametani, Naoki; Kato, Yukihiro; Yamagata, Shigehito; Nakazawa, Kazunori; Kanehara, Isao; Ako, Eiji; Yamada, Nobuya; Nishimura, Shigehiko; Fujita, Shigeki; Taenaka, Naoyuki

    2015-11-01

    We encountered a case of cutaneous metastases from colorectal carcinoma. A 63-year-old woman underwent laparoscopic-assisted ileocecal resection for cecal cancer. Computed tomography (CT) showed multiple liver metastases. The tumor was diagnosed as a well-differentiated adenocarcinoma and was staged as pSE, pN1, sH2, ly1, v1, CP0cM0, fStage ?. She was treated with 33 courses of the 5-fluorouracil, Leucovorin, and irinotecan (FOLFIRI) regimen and 15 courses of the 5-fluorouracil, Leucovorin, and oxaliplatin (mFOLFOX6) plus bevacizumab regimen. Thirty-four months after resection, multiple cutaneous tumors were noted, predominantly on the lower abdomen, and we resected 2 of them. Histologically, the specimens were diagnosed as well-differentiated adenocarcinoma, which was similar to that of cecal carcinoma. After 1 course of regorafenib, she died 3 years after the primary surgical resection. PMID:26805285

  10. Computed tomography of osteoid osteoma.

    PubMed

    Firooznia, H; Rafii, M; Golimbu, C

    1985-07-01

    Computed tomography revealed a radiolucent nidus with a surrounding zone of osteosclerosis in 17 patients with osteoid osteoma. Plain films did not reveal any abnormality in 5 patients. Conventional tomography was negative in 3 patients. Computed tomography is the modality of choice for detection of osteoid osteoma when the lesion is deep-seated or when it occurs in complex anatomic regions with curvilinear and overlapping surfaces, such as acetabulum, knee, and spine. PMID:4017617

  11. National Orange Show Photovoltaic Demonstration

    SciTech Connect

    Dan Jimenez Sheri Raborn, CPA; Tom Baker

    2008-03-31

    National Orange Show Photovoltaic Demonstration created a 400KW Photovoltaic self-generation plant at the National Orange Show Events Center (NOS). The NOS owns a 120-acre state fairground where it operates an events center and produces an annual citrus fair known as the Orange Show. The NOS governing board wanted to employ cost-saving programs for annual energy expenses. It is hoped the Photovoltaic program will result in overall savings for the NOS, help reduce the State's energy demands as relating to electrical power consumption, improve quality of life within the affected grid area as well as increase the energy efficiency of buildings at our venue. In addition, the potential to reduce operational expenses would have a tremendous effect on the ability of the NOS to service its community.

  12. Arches showing UV flaring activity

    NASA Technical Reports Server (NTRS)

    Fontenla, J. M.

    1988-01-01

    The UVSP data obtained in the previous maximum activity cycle show the frequent appearance of flaring events in the UV. In many cases these flaring events are characterized by at least two footpoints which show compact impulsive non-simultaneous brightenings and a fainter but clearly observed arch developes between the footpoints. These arches and footpoints are observed in line corresponding to different temperatures, as Lyman alpha, N V, and C IV, and when observed above the limb display large Doppler shifts at some stages. The size of the arches can be larger than 20 arcsec.

  13. Positron emission tomography and computed tomography assessments of the aging human brain

    SciTech Connect

    de Leon, M.J.; George, A.E.; Ferris, S.H.; Christman, D.R.; Fowler, J.S.; Gentes, C.I.; Brodie, J.; Reisberg, B.; Wolf, A.P.

    1984-02-01

    The relationship between alterations in brain structure and brain function was studied in vivo in both young and elderly human subjects. Computed tomography revealed significant age-related ventricular and cortical sulcal dilatation. The cortical changes were most closely related to age. Positron emission tomography failed to show regional changes in brain glucose metabolic rate. The results suggest that the normal aging brain undergoes structural atrophic changes without incurring regional metabolic changes. Examination of the correlations between the structural and the metabolic measures revealed no significant relationships. These data are discussed with respect to the significant structure-function relationships that have been reported in Alzheimer disease. 27 references, 3 figures, 2 tables.

  14. Statistical reconstruction for cosmic ray muon tomography.

    PubMed

    Schultz, Larry J; Blanpied, Gary S; Borozdin, Konstantin N; Fraser, Andrew M; Hengartner, Nicolas W; Klimenko, Alexei V; Morris, Christopher L; Orum, Chris; Sossong, Michael J

    2007-08-01

    Highly penetrating cosmic ray muons constantly shower the earth at a rate of about 1 muon per cm2 per minute. We have developed a technique which exploits the multiple Coulomb scattering of these particles to perform nondestructive inspection without the use of artificial radiation. In prior work [1]-[3], we have described heuristic methods for processing muon data to create reconstructed images. In this paper, we present a maximum likelihood/expectation maximization tomographic reconstruction algorithm designed for the technique. This algorithm borrows much from techniques used in medical imaging, particularly emission tomography, but the statistics of muon scattering dictates differences. We describe the statistical model for multiple scattering, derive the reconstruction algorithm, and present simulated examples. We also propose methods to improve the robustness of the algorithm to experimental errors and events departing from the statistical model. PMID:17688203

  15. High frequency electromagnetic tomography

    SciTech Connect

    Daily, W.; Ramirez, A.; Ueng, T.; Latorre, R.

    1989-09-01

    An experiment was conducted in G Tunnel at the Nevada Test Site to evaluate high frequency electromagnetic tomography as a candidate for in situ monitoring of hydrology in the near field of a heater placed in densely welded tuff. Tomographs of 200 MHz electromagnetic permittivity were made for several planes between boreholes. Data were taken before the heater was turned on, during heating and during cooldown of the rockmass. This data is interpreted to yield maps of changes in water content of the rockmass as a function of time. This interpretation is based on laboratory measurement of electromagnetic permittivity as a function of water content for densely welded tuff. 8 refs., 6 figs.

  16. Stored luminescence computed tomography

    NASA Astrophysics Data System (ADS)

    Cong, Wenxiang; Wang, Chao; Wang, Ge

    2014-09-01

    The phosphor nanoparticles made of doped semiconductors, pre-excited by well-collimated X-ray radiation, were recently reported for their light emission upon NIR light stimulation. The characteristics of X-ray energy storage and NIR stimulated emission is highly desirable to design targeting probes and improve molecular and cellular imaging. Here we propose stored luminescence computed tomography (SLCT), perform realistic numerical simulation, and demonstrate a much-improved spatial resolution in a preclinical research context. The future opportunities are also discussed along this direction.

  17. Computed tomography motor

    SciTech Connect

    Amor, W.H.; Dobbs, J.; Zupancie, A.Z.; Levar, R.E.

    1988-02-02

    In a computed tomography scanner this patent describes an apparatus comprising: a gantry supporting an annular array of detectors defining an X-ray scanning plane, the gantry having a through-passage with a generally cylindrical inside diameter; a frame coupled to the gantry for rotation relative to the gantry, the frame supporting an X-ray source for irradiating a subject of interest in the plane as the gantry and the frame rotate relative to each other; a bearing for rotatably coupling the frame and gantry, and an induction motor for imparting relative rotation between the frame and gantry.

  18. DIY Tomography sample holder

    NASA Astrophysics Data System (ADS)

    Lari, L.; Wright, I.; Boyes, E. D.

    2015-10-01

    A very simple tomography sample holder at minimal cost was developed in-house. The holder is based on a JEOL single tilt fast exchange sample holder where its exchangeable tip was modified to allow high angle degree tilt. The shape of the tip was designed to retain mechanical stability while minimising the lateral size of the tip. The sample can be mounted on as for a standard 3mm Cu grids as well as semi-circular grids from FIB sample preparation. Applications of the holder on different sample systems are shown.

  19. Radial reflection diffraction tomography

    DOEpatents

    Lehman, Sean K.

    2012-12-18

    A wave-based tomographic imaging method and apparatus based upon one or more rotating radially outward oriented transmitting and receiving elements have been developed for non-destructive evaluation. At successive angular locations at a fixed radius, a predetermined transmitting element can launch a primary field and one or more predetermined receiving elements can collect the backscattered field in a "pitch/catch" operation. A Hilbert space inverse wave (HSIW) algorithm can construct images of the received scattered energy waves using operating modes chosen for a particular application. Applications include, improved intravascular imaging, bore hole tomography, and non-destructive evaluation (NDE) of parts having existing access holes.

  20. Compressive Phase Contrast Tomography

    SciTech Connect

    Maia, Filipe; MacDowell, Alastair; Marchesini, Stefano; Padmore, Howard A.; Parkinson, Dula Y.; Pien, Jack; Schirotzek, Andre; Yang, Chao

    2010-09-01

    When x-rays penetrate soft matter, their phase changes more rapidly than their amplitude. Interference effects visible with high brightness sources creates higher contrast, edge enhanced images. When the object is piecewise smooth (made of big blocks of a few components), such higher contrast datasets have a sparse solution. We apply basis pursuit solvers to improve SNR, remove ring artifacts, reduce the number of views and radiation dose from phase contrast datasets collected at the Hard X-Ray Micro Tomography Beamline at the Advanced Light Source. We report a GPU code for the most computationally intensive task, the gridding and inverse gridding algorithm (non uniform sampled Fourier transform).

  1. Dermatofibrosarcoma Protuberans: Computed Tomography and Magnetic Resonance Imaging Findings

    PubMed Central

    Zhang, Liang; Liu, Qing-yu; Cao, Yun; Zhong, Jin-shuang; Zhang, Wei-dong

    2015-01-01

    Abstract The aim of this study was to analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of dermatofibrosarcoma protuberans (DFSP), with a view to improving the diagnosis of this kind of tumor. A total of 27 cases of histopathologically confirmed DFSP were analyzed retrospectively. Of these, 18 patients underwent a CT scan and 9 patients underwent an MRI. All patients underwent unenhanced and contrast-enhanced examinations; 1 patient underwent multiphrase CT enhancement examination. Imaging characteristics, including location, shape, size, number, edge, and attenuation or intensity of each lesion, both unenhanced and contrast enhanced, were analyzed. Of the 27 cases, 24 were solitary, 2 had 2 nodules, and 1 had multiple confluent tumors. The lesion with multiple confluent tumors was ill defined and irregular; the other lesions were oval or round, well-defined nodules or masses. The unenhanced CT images showed 19 homogenous isodense lesions. There was no calcification in any of the patients. The contrast-enhanced CT images showed intermediate and marked nonhomogeneous enhancement in 13 lesions, intermediate homogeneous enhancement in 4 lesions, and a mild heterogeneous enhancement in 2 lesions. MR T1-weighted images revealed 1 ill-defined and 9 well-defined homogeneous isointense lesions. T2-weighted images showed homogeneous hyperintensity to the muscles in 6 lesions, 3 mild hyperintense lesions with hypointense lesions, and 1 mixed, mild hyperintense and isointense lesion. Contrast-enhanced T1-weighted images demonstrated intermediate and marked nonhomogeneous enhancement in 9 lesions and intermediate homogeneous enhancement in 1 lesion. DFSP is characterized by a subcutaneous well-defined soft tissue nodule or mass on plain CT/MR scans, and shows intermediate-to-marked enhancement on contrast-enhanced CT/MR scans. The imaging findings for DFSP are nonspecific, but may help to define the diagnosis in an appropriate clinical setting. PMID:26091446

  2. Percutaneous management of multiple liver abscesses

    SciTech Connect

    Greenwood, L.H.; Collins, T.L.; Yrizarry, J.M.

    1982-08-01

    Percutaneous catheter drainage is now an accepted technique in the management of hepatic and other intraabdominal abscesses. Most abscesses accepted by the radiologist for drainage are unilocular with a safe percutaneous approach. This report demonstrates that even multiple hepatic abscesses may be successfully managed by percutaneous drainage. The use of computed tomography (CT) for diagnosis and sonography for safe puncture guidance is discussed.

  3. Multiple taurodontism: the challenge of endodontic treatment.

    PubMed

    Marques-da-Silva, Bruno; Baratto-Filho, Flares; Abuabara, Allan; Moura, Paula; Losso, Estela M; Moro, Alexandre

    2010-12-01

    This article describe a rare case of multiple taurodontism involving all molars in a 17-year-old male. Volumetric cone-beam computed tomography was used to investigate internal and external root morphology, including that of a maxillary first molar which required endodontic treatment and retreatment. Medical history was not contributory; however, Klinefelter syndrome was the diagnostic hypothesis in this case. PMID:21206170

  4. Contrast-enhanced fluorodeoxyglucose positron emission tomography/contrast-enhanced computed tomography in mediastinal T-cell lymphoma with superior vena cava syndrome

    PubMed Central

    Santhosh, Sampath; Gorla, Arun Kumar Reddy; Bhattacharya, Anish; Varma, Subhash Chander; Mittal, Bhagwant Rai

    2016-01-01

    Positron emission tomography-computed tomography (PET/CT) is a routine investigation for the staging of lymphomas. Contrast-enhanced computed tomography is mandatory whenever parenchymal lesions, especially in the liver and spleen are suspected. We report a rare case of primary mediastinal T-cell lymphoma evaluated with contrast-enhanced PET/CT that showed features of superior vena cava syndrome. PMID:26917907

  5. Imaging of in vitro and in vivo bones and joints with continuous-wave diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Xu, Yong; Iftimia, Nicusor V.; Jiang, Huabei; Lyndon Key, L.; Bolster, Marcy B.

    2001-03-01

    WWe present what is believed to be the first absorption and scattering images of in vitro and in vivo bones and joints from continuous-wave tomographic measurements. Human finger and chicken bones embedded in cylindrical scattering media were imaged at multiple transverse planes with Clemson multi-channel diffuse optical imager. Both absorption and scattering images were obtained using our nonlinear, finite element based reconstruction algorithm. This study shows that diffuse optical tomography (DOT) has the potential to be used for detection and monitoring of bone and joint diseases such as osteoporosis and arthritis.

  6. A case of multiple bone fractures due to the use of topical corticosteroid therapy for psoriasis.

    PubMed

    Gnl, Mzeyyen; Gnl, Engin

    2015-06-01

    A 45-year-old man who had psoriasis had applied topical clobetasol 17 propionate ointment on his whole body 2-3 times a week after the bath for 20 years. Physical examination showed abdominal distension, atrophy all over the skin, psoriatic plaques on the trunk, and extremities and multiple striae on the shoulders and legs. Morning plasma cortisol level and ACTH stimulation test confirmed the diagnosis of hypothalamic insufficiency. Bone mineral densitometry showed severe osteoporosis. Multiple bone fractures in the vertebrae and costa were detected on lumbar magnetic resonance imaging, the (99)Tc MDP whole-body bone scan, and thoracoabdominal computerized tomography imaging. Topical corticosteroid therapies have possible local and/or systemic side effects such as atrophy, telangiectasia, hypertricosis, and suppression of pituitary-adrenal axis. We present an interesting case with multiple bone fractures caused by long-time topical corticosteroid use. PMID:24913132

  7. ENVITEC shows off air technologies

    SciTech Connect

    McIlvaine, R.W.

    1995-08-01

    The ENVITEC International Trade Fair for Environmental Protection and Waste Management Technologies, held in June in Duesseldorf, Germany, is the largest air pollution exhibition in the world and may be the largest environmental technology show overall. Visitors saw thousands of environmental solutions from 1,318 companies representing 29 countries and occupying roughly 43,000 square meters of exhibit space. Many innovations were displayed under the category, ``thermal treatment of air pollutants.`` New technologies include the following: regenerative thermal oxidizers; wet systems for removing pollutants; biological scrubbers;electrostatic precipitators; selective adsorption systems; activated-coke adsorbers; optimization of scrubber systems; and air pollution monitors.

  8. 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.

  9. Inferring North-American continental evolution from seismic tomography

    NASA Astrophysics Data System (ADS)

    van der Lee, S.; Bedle, H.; Jacobsen, S.; Lou, X.; Regenauer-Lieb, K.; Yuen, D.

    2008-12-01

    Seismic tomography has long been a powerful tool for inferring present-day structural variations within the mantle in three dimensions, but does not provide explicit information on the evolution of the mantle. However, in conjunction with geodynamic modeling, mineral physcis, geology, tectonophysics, and geodesy, seismic tomography can provide critical clues to the evolution of the mantle and overlying continents. Moreover, current trends in seismic-tomographic inversion modeling, which combine ever more information from different types of seismic data in joint inversions, yield more exclusive (better constrained) models, simultaneously consistent with multiple types of data. Finally, and most relevant for North America, Earthscope has been providing the mix of data needed to conjecture the general and unique aspects of the past and future evolution of the North-American continent. The North American upper mantle has stood out for the large S-velocity contrast across the Rocky Mountain Front and the lower mantle for the dipping high S-velocity anomaly representing the Mesozoic Farallon Plate. Through pairing seismic-tomographic results with plate-tectonic reconstructions, timing of past mountain building, volcanism, and other deformation, geodynamic modeling, and mineral physics, we work out implications of these and smaller-scale structures for the Cenozoic history as well as for the near tectonic future of the continent. Recent results show an enigmatic transition zone with ubiquitous high velocities and an elongated low-velocity zone beneath the Appalachian Mountain Front. We reason how this zone might represent the critical clue to the connection between past tectonics, involving the subduction of the Farallon Plate and associated mountain building, volcanism, and other deformation in the west, to future tectonics, potentially involving subduction of the Atlantic Ocean's lithosphere below the now passive eastern continental margin.

  10. ShowMe3D

    SciTech Connect

    2012-01-05

    ShowMe3D is a data visualization graphical user interface specifically designed for use with hyperspectral image obtained from the Hyperspectral Confocal Microscope. The program allows the user to select and display any single image from a three dimensional hyperspectral image stack. By moving a slider control, the user can easily move between images of the stack. The user can zoom into any region of the image. The user can select any pixel or region from the displayed image and display the fluorescence spectrum associated with that pixel or region. The user can define up to 3 spectral filters to apply to the hyperspectral image and view the image as it would appear from a filter-based confocal microscope. The user can also obtain statistics such as intensity average and variance from selected regions.

  11. "Show me" bioethics and politics.

    PubMed

    Christopher, Myra J

    2007-10-01

    Missouri, the "Show Me State," has become the epicenter of several important national public policy debates, including abortion rights, the right to choose and refuse medical treatment, and, most recently, early stem cell research. In this environment, the Center for Practical Bioethics (formerly, Midwest Bioethics Center) emerged and grew. The Center's role in these "cultural wars" is not to advocate for a particular position but to provide well researched and objective information, perspective, and advocacy for the ethical justification of policy positions; and to serve as a neutral convener and provider of a public forum for discussion. In this article, the Center's work on early stem cell research is a case study through which to argue that not only the Center, but also the field of bioethics has a critical role in the politics of public health policy. PMID:17926217

  12. ShowMe3D

    Energy Science and Technology Software Center (ESTSC)

    2012-01-05

    ShowMe3D is a data visualization graphical user interface specifically designed for use with hyperspectral image obtained from the Hyperspectral Confocal Microscope. The program allows the user to select and display any single image from a three dimensional hyperspectral image stack. By moving a slider control, the user can easily move between images of the stack. The user can zoom into any region of the image. The user can select any pixel or region from themore » displayed image and display the fluorescence spectrum associated with that pixel or region. The user can define up to 3 spectral filters to apply to the hyperspectral image and view the image as it would appear from a filter-based confocal microscope. The user can also obtain statistics such as intensity average and variance from selected regions.« less

  13. Phoenix Scoop Inverted Showing Rasp

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image taken by the Surface Stereo Imager on Sol 49, or the 49th Martian day of the mission (July 14, 2008), shows the silver colored rasp protruding from NASA's Phoenix Mars Lander's Robotic Arm scoop. The scoop is inverted and the rasp is pointing up.

    Shown with its forks pointing toward the ground is the thermal and electrical conductivity probe, at the lower right. The Robotic Arm Camera is pointed toward the ground.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is led by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  14. Multiple feeding vessels from left circumflex artery and right coronary artery to myxoma in left atrium

    PubMed Central

    Kim, Tae-Jin; Kim, Jae-Kyun; Seo, Guang-Won; Park, Bo-Min; Song, Pil-Sang; Kim, Dong-Kie; Kim, Ki-Hun; Kim, Doo-Il; Jun, Hee-Jae

    2013-01-01

    A 62-year-old woman with six months history of dizziness was admitted to our hospital. A large mass in the left atrium was detected by transthoracic echocardiography. Coronary angiography showed two feeding arteries from the right coronary artery and left circumflex artery to the left atrium. Chest computed tomography, coronary computed tomographic angiography and contrast echocardiography were performed. Those showed multiple intratumoral neovascularities from surface of the mass. After those examinations, the mass was completely resected. Histopathologic examination confirmed the diagnosis of cardiac myxoma. There was no abnormal remnant mass, based on a follow-up transthoracic echocardiography. PMID:24416523

  15. Nanoscale TEM tomography of metal oxide photocatalyst systems.

    SciTech Connect

    Antolak, Arlyn J.; Lucadamo, Gene Anthony

    2004-08-01

    Transmission electron microscope (TEM) tomography provides three-dimensional structural information from tilt series with nanoscale resolution. We have collected TEM projection data sets to study the internal structure of photocatalytic nanoparticles. Multiple cross-sectional slices of the nanoparticles are reconstructed using an algebraic reconstruction technique (ART) and then assembled to form a 3D rendering of the object. We recently upgraded our TEM with a new sample holder having a tilt range of +/-70{sup o} and have collected tomography data over a range of 125{sup o}. Simulations were performed to study the effects of field-of-view displacement (shift and rotation), limited tilt angle range, hollow (missing) projections, stage angle accuracy, and number of projections on the reconstructed image quality. This paper discusses our experimental and computational approaches, presents some examples of TEM tomography, and considers future directions.

  16. Mapping distributed brain function and networks with diffuse optical tomography

    PubMed Central

    Eggebrecht, Adam T.; Ferradal, Silvina L.; Robichaux-Viehoever, Amy; Hassanpour, Mahlega S.; Dehghani, Hamid; Snyder, Abraham Z.; Hershey, Tamara; Culver, Joseph P.

    2014-01-01

    Mapping of human brain function has revolutionized systems neuroscience. However, traditional functional neuroimaging by positron emission tomography or functional magnetic resonance imaging cannot be used when applications require portability, or are contraindicated because of ionizing radiation (positron emission tomography) or implanted metal (functional magnetic resonance imaging). Optical neuroimaging offers a non-invasive alternative that is radiation free and compatible with implanted metal and electronic devices (for example, pacemakers). However, optical imaging technology has heretofore lacked the combination of spatial resolution and wide field of view sufficient to map distributed brain functions. Here, we present a high-density diffuse optical tomography imaging array that can map higher-order, distributed brain function. The system was tested by imaging four hierarchical language tasks and multiple resting-state networks including the dorsal attention and default mode networks. Finally, we imaged brain function in patients with Parkinsons disease and implanted deep brain stimulators that preclude functional magnetic resonance imaging. PMID:25083161

  17. Mapping distributed brain function and networks with diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Eggebrecht, Adam T.; Ferradal, Silvina L.; Robichaux-Viehoever, Amy; Hassanpour, Mahlega S.; Dehghani, Hamid; Snyder, Abraham Z.; Hershey, Tamara; Culver, Joseph P.

    2014-06-01

    Mapping of human brain function has revolutionized systems neuroscience. However, traditional functional neuroimaging by positron emission tomography or functional magnetic resonance imaging cannot be used when applications require portability, or are contraindicated because of ionizing radiation (positron emission tomography) or implanted metal (functional magnetic resonance imaging). Optical neuroimaging offers a non-invasive alternative that is radiation free and compatible with implanted metal and electronic devices (for example, pacemakers). However, optical imaging technology has heretofore lacked the combination of spatial resolution and wide field of view sufficient to map distributed brain functions. Here, we present a high-density diffuse optical tomography imaging array that can map higher-order, distributed brain function. The system was tested by imaging four hierarchical language tasks and multiple resting-state networks including the dorsal attention and default mode networks. Finally, we imaged brain function in patients with Parkinson's disease and implanted deep brain stimulators that preclude functional magnetic resonance imaging.

  18. Multiple Fan-Beam Optical Tomography: Modelling Techniques

    PubMed Central

    Rahim, Ruzairi Abdul; Chen, Leong Lai; San, Chan Kok; Rahiman, Mohd Hafiz Fazalul; Fea, Pang Jon

    2009-01-01

    This paper explains in detail the solution to the forward and inverse problem faced in this research. In the forward problem section, the projection geometry and the sensor modelling are discussed. The dimensions, distributions and arrangements of the optical fibre sensors are determined based on the real hardware constructed and these are explained in the projection geometry section. The general idea in sensor modelling is to simulate an artificial environment, but with similar system properties, to predict the actual sensor values for various flow models in the hardware system. The sensitivity maps produced from the solution of the forward problems are important in reconstructing the tomographic image. PMID:22291523

  19. Multiple Object Adaptive Optics: Mixed NGS/LGS tomography

    NASA Astrophysics Data System (ADS)

    Morris, Tim; Gendron, Eric; Basden, Alastair; Martin, Olivier; Osborn, James; Henry, David; Hubert, Zoltan; Sivo, Gaetano; Gratadour, Damien; Chemla, Fanny; Sevin, Arnaud; Cohen, Matthieu; Younger, Eddy; Vidal, Fabrice; Wilson, Richard; Batterley, Tim; Bitenc, Urban; Reeves, Andrew; Bharmal, Nazim; Raynaud, Henri-François; Kulcsar, Caroline; Conan, Jean-Marc; Guzman, Dani; De Cos Juez, Javier; Huet, Jean-Michel; Perret, Denis; Dickson, Colin; Atkinson, David; Baillie, Tom; Longmore, Andy; Todd, Stephen; Talbot, Gordon; Morris, Simon; Myers, Richard; Rousset, Gérard

    2013-12-01

    Open-loop adaptive optics has been successfully demonstrated on-sky by several groups, including the fully tomographic MOAO demonstration made using CANARY. MOAO instrumentation such as RAVEN will deliver the first astronomical science and other planned instruments aim to extend both open-loop AO performance and the number of corrected fields. Many of these planned systems rely on the use of tomographic open-loop LGS wavefront sensing. Here we present results from the combined NGS/LGS tomographic CANARY system and then compare the NGS- and LGS-based tomographic system performance. We identify the major system performance drivers, and highlight some potential routes for further exploitation of open-loop tomographic AO.

  20. Casimir experiments showing saturation effects

    SciTech Connect

    Sernelius, Bo E.

    2009-10-15

    We address several different Casimir experiments where theory and experiment disagree. First out is the classical Casimir force measurement between two metal half spaces; here both in the form of the torsion pendulum experiment by Lamoreaux and in the form of the Casimir pressure measurement between a gold sphere and a gold plate as performed by Decca et al.; theory predicts a large negative thermal correction, absent in the high precision experiments. The third experiment is the measurement of the Casimir force between a metal plate and a laser irradiated semiconductor membrane as performed by Chen et al.; the change in force with laser intensity is larger than predicted by theory. The fourth experiment is the measurement of the Casimir force between an atom and a wall in the form of the measurement by Obrecht et al. of the change in oscillation frequency of a {sup 87}Rb Bose-Einstein condensate trapped to a fused silica wall; the change is smaller than predicted by theory. We show that saturation effects can explain the discrepancies between theory and experiment observed in all these cases.

  1. Lamb wave diffraction tomography

    NASA Astrophysics Data System (ADS)

    Malyarenko, Eugene Valentinovich

    As the worldwide aviation fleet continues to age, methods for accurately predicting the presence of structural flaws, such as hidden corrosion and disbonds, that compromise air worthiness become increasingly necessary. Ultrasonic guided waves, Lamb waves, allow large sections of aircraft structures to be rapidly inspected. However, extracting quantitative information from Lamb wave data has always involved highly trained personnel with a detailed knowledge of mechanical waveguide physics. In addition, human inspection process tends to be highly subjective, slow and prone to errors. The only practical alternative to traditional inspection routine is a software expert system capable of interpreting data with minimum error and maximum speed and reliability. Such a system would use the laws of guided wave propagation and material parameters to help signal processing algorithms automatically extract information from digitized waveforms. This work discusses several practical approaches to building such an expert system. The next step in the inspection process is data interpretation, and imaging is the most natural way to represent two-dimensional structures. Unlike conventional ultrasonic C-scan imaging that requires access to the whole inspected area, tomographic algorithms work with data collected over the perimeter of the sample. Combined with the ability of Lamb waves to travel over large distances, tomography becomes the method of choice for solving NDE problems. This work explores different tomographic reconstruction techniques to graphically represent the Lamb wave data in quantitative maps that can be easily interpreted by technicians. Because the velocity of Lamb waves depends on the thickness, the traveltimes of the fundamental modes can be converted into a thickness map of the inspected region. Lamb waves cannot penetrate through holes and other strongly scattering defects and the assumption of straight wave paths, essential for many tomographic algorithms, fails. Diffraction tomography is a way to incorporate scattering effects into tomographic algorithms in order to improve image quality and resolution. This work describes the iterative reconstruction procedure developed for the Lamb Wave tomography and allowing for ray bending correction for imaging of moderately scattering objects.

  2. EDITORIAL: Industrial Process Tomography

    NASA Astrophysics Data System (ADS)

    Anton Johansen, Geir; Wang, Mi

    2008-09-01

    There has been tremendous development within measurement science and technology over the past couple of decades. New sensor technologies and compact versatile signal recovery electronics are continuously expanding the limits of what can be measured and the accuracy with which this can be done. Miniaturization of sensors and the use of nanotechnology push these limits further. Also, thanks to powerful and cost-effective computer systems, sophisticated measurement and reconstruction algorithms previously only accessible in advanced laboratories are now available for in situ online measurement systems. The process industries increasingly require more process-related information, motivated by key issues such as improved process control, process utilization and process yields, ultimately driven by cost-effectiveness, quality assurance, environmental and safety demands. Industrial process tomography methods have taken advantage of the general progress in measurement science, and aim at providing more information, both quantitatively and qualitatively, on multiphase systems and their dynamics. The typical approach for such systems has been to carry out one local or bulk measurement and assume that this is representative of the whole system. In some cases, this is sufficient. However, there are many complex systems where the component distribution varies continuously and often unpredictably in space and time. The foundation of industrial tomography is to conduct several measurements around the periphery of a multiphase process, and use these measurements to unravel the cross-sectional distribution of the process components in time and space. This information is used in the design and optimization of industrial processes and process equipment, and also to improve the accuracy of multiphase system measurements in general. In this issue we are proud to present a selection of the 145 papers presented at the 5th World Congress on Industrial Process Tomography in Bergen, September 2007. Interestingly, x-ray technologies, one of the first imaging modalities available, keep on moving the limits on both spatial and temporal measurement resolution; experimental results of less than 100 nm and several thousand frames/s are reported, respectively. Important progress is demonstrated in research and development on sensor technologies and algorithms for data processing and image reconstruction, including unconventional sensor design and adaptation of the sensors to the application in question. The number of applications to which tomographic methods are applied is steadily increasing, and results obtained in a representative selection of applications are included. As guest editors we would like express our appreciation and thanks to all authors who have contributed and to IOP staff for excellent collaboration in the process of finalizing this special feature.

  3. Optical coherence tomography accurately identifies patients with penile (pre) malignant lesions: A single center prospective study

    PubMed Central

    Wessels, Ronni; De Bruin, Daniel M.; Faber, Dirk J.; Horenblas, Simon; van Rhijn, Bas W. G.; Vincent, Andrew D.; van Beurden, Marc; van Leeuwen, Ton G.; Ruers, Theo J. M.

    2015-01-01

    Introduction: Currently, (multiple) biopsies are taken to obtain histopathological diagnosis of suspicious lesions of the penile skin. Optical coherence tomography (OCT) provides noninvasive in vivo images from which epidermal layer thickness and attenuation coefficient (?oct) can be quantified. We hypothesize that qualitative (image assessment) and quantitative (epidermal layer thickness and attenuation coefficient, ?oct) analysis of penile skin with OCT is possible and may differentiate benign penile tissue from (pre) malignant penile tissue. Materials and Methods: Optical coherence tomography-imaging was performed prior to punch biopsy in 18 consecutive patients with a suspicious lesion at the outpatient clinic of the NKI-AVL. Qualitative analysis consisted of visual assessment of clear layers and a visible lower border of the lesions, quantitative analysis comprised of determination of the epidermal layer thickness and ?oct. Results were grouped according to histopathology reports. Results: Qualitative analysis showed a statistically significant difference (P = 0.047) between benign and (pre) malignant lesions. Quantitative analysis showed that epidermal layer thickness and attenuation coefficient was significantly different between benign and (pre) malignant tissue, respectively, P = 0.001 and P < 0.001. Conclusion: In this preliminary study, qualitative and quantitative analysis of OCT-images of suspicious penile lesions shows differences between benign lesions and (pre) malignant lesions. These results encourage further research in a larger study population. PMID:26692665

  4. 4-D Photoacoustic Tomography

    NASA Astrophysics Data System (ADS)

    Xiang, Liangzhong; Wang, Bo; Ji, Lijun; Jiang, Huabei

    2013-01-01

    Photoacoustic tomography (PAT) offers three-dimensional (3D) structural and functional imaging of living biological tissue with label-free, optical absorption contrast. These attributes lend PAT imaging to a wide variety of applications in clinical medicine and preclinical research. Despite advances in live animal imaging with PAT, there is still a need for 3D imaging at centimeter depths in real-time. We report the development of four dimensional (4D) PAT, which integrates time resolutions with 3D spatial resolution, obtained using spherical arrays of ultrasonic detectors. The 4D PAT technique generates motion pictures of imaged tissue, enabling real time tracking of dynamic physiological and pathological processes at hundred micrometer-millisecond resolutions. The 4D PAT technique is used here to image needle-based drug delivery and pharmacokinetics. We also use this technique to monitor 1) fast hemodynamic changes during inter-ictal epileptic seizures and 2) temperature variations during tumor thermal therapy.

  5. 4-D Photoacoustic Tomography

    PubMed Central

    Xiang, Liangzhong; Wang, Bo; Ji, Lijun; Jiang, Huabei

    2013-01-01

    Photoacoustic tomography (PAT) offers three-dimensional (3D) structural and functional imaging of living biological tissue with label-free, optical absorption contrast. These attributes lend PAT imaging to a wide variety of applications in clinical medicine and preclinical research. Despite advances in live animal imaging with PAT, there is still a need for 3D imaging at centimeter depths in real-time. We report the development of four dimensional (4D) PAT, which integrates time resolutions with 3D spatial resolution, obtained using spherical arrays of ultrasonic detectors. The 4D PAT technique generates motion pictures of imaged tissue, enabling real time tracking of dynamic physiological and pathological processes at hundred micrometer-millisecond resolutions. The 4D PAT technique is used here to image needle-based drug delivery and pharmacokinetics. We also use this technique to monitor 1) fast hemodynamic changes during inter-ictal epileptic seizures and 2) temperature variations during tumor thermal therapy. PMID:23346370

  6. Fluorescence coherence tomography.

    PubMed

    Bilenca, A; Ozcan, A; Bouma, B; Tearney, G

    2006-08-01

    In this paper, we introduce a new form of cross-sectional, coherence-gated fluorescence imaging, which we term 'spectral-domain fluorescence coherence tomography' (SD-FCT). SD-FCT is accomplished by spectrally detecting self-interference of the spontaneous emission of fluorophores located along the axial (depth) dimension of the sample. We have built a first generation SD-FCT system that utilizes two opposing low numerical-aperture objective lenses in an interferometer and an imaging spectrometer for detecting self-interference of fluorescence emitted from a sample. Here, in proof-of-principle experiments we demonstrate cross-sectional profiling of layered fluorescence phantoms. Narrow (a few micrometers FWHM) axial point-spread functions, large ranging depths (a few hundreds of micrometers) and wide fields of view (>1 mm) were measured. Initial results suggest that SD-FCT may be a viable tool for the investigation of semi-transparent and selectively labeled fluorescent samples. PMID:19529084

  7. Contactless inductive flow tomography

    NASA Astrophysics Data System (ADS)

    Stefani, Frank; Gundrum, Thomas; Gerbeth, Gunter

    2004-11-01

    The three-dimensional velocity field of a propeller-driven liquid metal flow is reconstructed by a contactless inductive flow tomography. The underlying theory is presented within the framework of an integral equation system that governs the magnetic field distribution in a moving electrically conducting fluid. For small magnetic Reynolds numbers this integral equation system can be cast into a linear inverse problem for the determination of the velocity field from externally measured magnetic fields. A robust reconstruction of the large scale velocity field is already achieved by applying the external magnetic field alternately in two orthogonal directions and measuring the corresponding sets of induced magnetic fields. Kelvins theorem is exploited to regularize the resulting velocity field by using the kinetic energy of the flow as a regularizing functional. The results of this technique are shown to be in satisfactory agreement with ultrasonic measurements.

  8. Stored luminescence computed tomography.

    PubMed

    Cong, Wenxiang; Wang, Chao; Wang, Ge

    2014-09-01

    Phosphor nanoparticles made of doped semiconductors and pre-excited by x-ray radiation were recently reported for their luminescence emission in the range of 650-770nm upon near-infrared (NIR) light stimulation. These nanophosphors can be functionalized as optical probes for molecular imaging. In this paper, we present stored luminescence computed tomography to reconstruct a nanophosphor distribution in an object. The propagation of x rays in a biological object allows significantly better localization and deeper penetration. Moreover, the nanophosphors, which are pre-excited with collimated x-ray beams or focused x-ray waves, can be successively stimulated for stored luminescence emissions by variable NIR stimulation patterns. The sequentially detected luminescence signals provide more information of a nanophosphor spatial distribution for more accurate image reconstruction and higher image resolution. A realistic numerical study is performed to demonstrate the feasibility and merits of the proposed approach. PMID:25321362

  9. Optical coherence tomography image enhancement by using gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Ponce-de-Leon, Y. R.; Lopez-Rios, J. A.; Pichardo-Molina, J. L.; Alcal Ochoa, N.

    2011-08-01

    Optical Coherence Tomography (OCT) is an imaging technique to get cross-sectional images with resolutions of a few microns and deep penetration in tissue of some millimeters. For many years OCT has been applied to analyze different human tissues like eyes, skin, teeth, urinary bladders, gastrointestinal, respiratory or genitourinary tracts and recently breast cancer tissues have been studied. Many of these tissues are composed specially of lipids and collagen, proteins which cause multiple light scattering (MLS) reducing significantly the optical depth and the contrast of OCT imaging. So, one of the big challenges of this technique is to acquire images with good contrast. Gold nanoparticles (NPs) exhibit interesting optical properties due to its plasmon resonance frequency. Optical absorbance is strong when gold NPs have dimension under 50 nm, but over this size optical scattering becomes dominant. In this work we show the preliminary results of the use of gold NPs as a contrast medium to enhance the OCT images quality. Our experimental results show which type of particles (morphology and size) present the best enhancement in the region of 1325 nm which corresponds to the central wavelength source excitation. All our experiments were carried out with a commercial OCT (thorlabs) system and our NPs were tested in water and gel phantoms.

  10. Global Adjoint Tomography

    NASA Astrophysics Data System (ADS)

    Bozdag, Ebru; Lefebvre, Matthieu; Lei, Wenjie; Peter, Daniel; Smith, James; Komatitsch, Dimitri; Tromp, Jeroen

    2015-04-01

    We will present our initial results of global adjoint tomography based on 3D seismic wave simulations which is one of the most challenging examples in seismology in terms of intense computational requirements and vast amount of high-quality seismic data that can potentially be assimilated in inversions. Using a spectral-element method, we incorporate full 3D wave propagation in seismic tomography by running synthetic seismograms and adjoint simulations to compute exact sensitivity kernels in realistic 3D background models. We run our global simulations on the Oak Ridge National Laboratory's Cray XK7 "Titan" system taking advantage of the GPU version of the SPECFEM3D_GLOBE package. We have started iterations with initially selected 253 earthquakes within the magnitude range of 5.5 < Mw < 7.0 and numerical simulations having resolution down to ~27 s to invert for a transversely isotropic crust and mantle model using a non-linear conjugate gradient algorithm. The measurements are currently based on frequency-dependent traveltime misfits. We use both minor- and major-arc body and surface waves by running 200 min simulations where inversions are performed with more than 2.6 million measurements. Our initial results after 12 iterations already indicate several prominent features such as enhanced slab (e.g., Hellenic, Japan, Bismarck, Sandwich), plume/hotspot (e.g., the Pacific superplume, Caroline, Yellowstone, Hawaii) images, etc. To improve the resolution and ray coverage, particularly in the lower mantle, our aim is to increase the resolution of numerical simulations first going down to ~17 s and then to ~9 s to incorporate high-frequency body waves in inversions. While keeping track of the progress and illumination of features in our models with a limited data set, we work towards to assimilate all available data in inversions from all seismic networks and earthquakes in the global CMT catalogue.

  11. Waste Inspection Tomography (WIT)

    SciTech Connect

    Bernardi, R.T.

    1995-12-01

    Waste Inspection Tomography (WIT) provides mobile semi-trailer mounted nondestructive examination (NDE) and assay (NDA) for nuclear waste drum characterization. WIT uses various computed tomography (CT) methods for both NDE and NDA of nuclear waste drums. Low level waste (LLW), transuranic (TRU), and mixed radioactive waste can be inspected and characterized without opening the drums. With externally transmitted x-ray NDE techniques, WIT has the ability to identify high density waste materials like heavy metals, define drum contents in two- and three-dimensional space, quantify free liquid volumes through density and x-ray attenuation coefficient discrimination, and measure drum wall thickness. With waste emitting gamma-ray NDA techniques, WIT can locate gamma emitting radioactive sources in two- and three-dimensional space, identify gamma emitting isotopic species, identify the external activity levels of emitting gamma-ray sources, correct for waste matrix attenuation, provide internal activity approximations, and provide the data needed for waste classification as LLW or TRU. The mobile feature of WIT allows inspection technologies to be brought to the nuclear waste drum storage site without the need to relocate drums for safe, rapid, and cost-effective characterization of regulated nuclear waste. The combination of these WIT characterization modalities provides the inspector with an unprecedented ability to non-invasively characterize the regulated contents of waste drums as large as 110 gallons, weighing up to 1,600 pounds. Any objects that fit within these size and weight restrictions can also be inspected on WIT, such as smaller waste bags and drums that are five and thirty-five gallons.

  12. Multiple homicides.

    PubMed

    Copeland, A R

    1989-09-01

    A study of multiple homicides or multiple deaths involving a solitary incident of violence by another individual was performed on the case files of the Office of the Medical Examiner of Metropolitan Dade County in Miami, Florida, during 1983-1987. A total of 107 multiple homicides were studied: 88 double, 17 triple, one quadruple, and one quintuple. The 236 victims were analyzed regarding age, race, sex, cause of death, toxicologic data, perpetrator, locale of the incident, and reason for the incident. This article compares this type of slaying with other types of homicide including those perpetrated by serial killers. Suggestions for future research in this field are offered. PMID:2782297

  13. Process tomography for unitary quantum channels

    SciTech Connect

    Gutoski, Gus; Johnston, Nathaniel

    2014-03-15

    We study the number of measurements required for quantum process tomography under prior information, such as a promise that the unknown channel is unitary. We introduce the notion of an interactive observable and we show that any unitary channel acting on a d-level quantum system can be uniquely identified among all other channels (unitary or otherwise) with only O(d{sup 2}) interactive observables, as opposed to the O(d{sup 4}) required for tomography of arbitrary channels. This result generalizes to the problem of identifying channels with at most q Kraus operators, and slight improvements can be obtained if we wish to identify such a channel only among unital channels or among other channels with q Kraus operators. These results are proven via explicit construction of large subspaces of Hermitian matrices with various conditions on rank, eigenvalues, and partial trace. Our constructions are built upon various forms of totally nonsingular matrices.

  14. Ionospheric tomography using ADS-B signals

    NASA Astrophysics Data System (ADS)

    Cushley, A. C.; Nol, J.-M.

    2014-07-01

    Numerical modeling has demonstrated that Automatic Dependent Surveillance Broadcast (ADS-B) signals can be used to reconstruct two-dimensional (2-D) electron density maps of the ionosphere using techniques for computerized tomography. Ray tracing techniques were used to determine the characteristics of individual waves, including the wave path and the state of polarization at the satellite receiver. The modeled Faraday rotation was computed and converted to total electron content (TEC) along the raypaths. The resulting TEC was used as input for computerized ionospheric tomography (CIT) using algebraic reconstruction technique. This study concentrated on reconstructing mesoscale structures 25-100 km in horizontal extent. The primary scientific interest of this study was to show that ADS-B signals can be used as a new source of data for CIT to image the ionosphere and to obtain a better understanding of magneto-ionic wave propagation.

  15. Grating-based tomography of human tissues

    NASA Astrophysics Data System (ADS)

    Mller, Bert; Schulz, Georg; Mehlin, Andrea; Herzen, Julia; Lang, Sabrina; Holme, Margaret; Zanette, Irene; Hieber, Simone; Deyhle, Hans; Beckmann, Felix; Pfeiffer, Franz; Weitkamp, Timm

    2012-07-01

    The development of therapies to improve our health requires a detailed knowledge on the anatomy of soft tissues from the human body down to the cellular level. Grating-based phase contrast micro computed tomography using synchrotron radiation provides a sensitivity, which allows visualizing micrometer size anatomical features in soft tissue without applying any contrast agent. We show phase contrast tomography data of human brain, tumor vessels and constricted arteries from the beamline ID 19 (ESRF) and urethral tissue from the beamline W2 (HASYLAB/DESY) with micrometer resolution. Here, we demonstrate that anatomical features can be identified within brain tissue as well known from histology. Using human urethral tissue, the application of two photon energies is compared. Tumor vessels thicker than 20 ?m can be perfectly segmented. The morphology of coronary arteries can be better extracted in formalin than after paraffin embedding.

  16. Self-calibrating tomography for multidimensional systems

    NASA Astrophysics Data System (ADS)

    Quesada, Nicols; Bra?czyk, Agata M.; James, Daniel F. V.

    2013-06-01

    Quantum state tomography relies on the ability to perform well-characterized unitary operations, which are not always available. This places restrictions on which physical systems can be characterized using such techniques. We develop a formalism that circumvents the requirement for well-characterized unitary operations by treating unknown parameters in the state and unitary process on the same footing, thereby simultaneously performing state and partial process tomography. Our formalism is generalized to d-level systems, and we provide a specific example for a V-type three-level atomic system whose transition dipole moments are not known. We show that it is always possible to retrieve not only the unknown state but also the process parameters, except for a set of zero measure in the state-parameter space.

  17. Whole breast tissue characterization with ultrasound tomography

    NASA Astrophysics Data System (ADS)

    Duric, Neb; Littrup, Peter; Li, Cuiping; Roy, Olivier; Schmidt, Steve; Seamans, John; Wallen, Andrea; Bey-Knight, Lisa

    2015-03-01

    A number of clinical trials have shown that screening ultrasound, supplemental to mammography, detects additional cancers in women with dense breasts. However, labor intensity, operator dependence and high recall rates have limited adoption. This paper describes the use of ultrasound tomography for whole-breast tissue stiffness measurements as a first step toward addressing the issue of high recall rates. The validation of the technique using an anthropomorphic phantom is described. In-vivo applications are demonstrated on 13 breast masses, indicating that lesion stiffness correlates with lesion type as expected. Comparison of lesion stiffness measurements with standard elastography was available for 11 masses and showed a strong correlation between the 2 measures. It is concluded that ultrasound tomography can map out the 3 dimensional distribution of tissue stiffness over the whole breast. Such a capability is well suited for screening where additional characterization may improve the specificity of screening ultrasound, thereby lowering barriers to acceptance.

  18. Multiple myeloma

    MedlinePLUS

    Plasma cell dyscrasia; Plasma cell myeloma; Malignant plasmacytoma; Plasmacytoma of bone; Myeloma - multiple ... National Cancer Institute: PDQ Plasma Cell Neoplasms (Including ... Institute. Date last modified: June 24, 2014. Available at: www. ...

  19. Non-Hodgkin's Lymphoma of Multiple Skeletal Muscles Involvement Seen on FDG PET/CT Scans.

    PubMed

    Dai, Yue; Sowjanya, Medapati; You, Jia; Xu, Kai

    2015-05-01

    As normal healthy skeletal muscle does not contain lymphoid tissue, extra nodal lymphoma involving multiple muscles is rare, as well. This study reports a case of non-Hodgkin's lymphoma (NHL) of multiple skeletal muscles involvement and a review of differential diagnosis of it.A 37-year-old female presented to our hospital after being diagnosed with NHL for 7 months. She had received six courses of cyclophosphamide hydroxydaunorubicin oncovin prednisolone etoposide (CHOPE) chemotherapy. Then she felt pain and noticed swelling on her left calf. The fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) image showed abnormal focal FDG uptake in hypo-pharynx, which was the primary NHL and also in multiple groups of muscles in whole body. As the patient has history NHL, lymphoma of multiple muscle involvement was suspected.Finally, an ultrasound-guided tissue biopsy was performed on the left calf and histological examination yielded lymphomatous cells infiltration in the left gastrocnemius.Through this report, we emphasize that a multidisciplinary team approach with clinician, radiologist, and pathologist is essential for proper diagnosis, staging, and management of such rare lesions. PMID:25950693

  20. 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)

  1. 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.

  2. Multifunctional, three-dimensional tomography for analysis of eletrectrohydrodynamic jetting

    NASA Astrophysics Data System (ADS)

    Nguyen, Xuan Hung; Gim, Yeonghyeon; Ko, Han Seo

    2015-05-01

    A three-dimensional optical tomography technique was developed to reconstruct three-dimensional objects using a set of two-dimensional shadowgraphic images and normal gray images. From three high-speed cameras, which were positioned at an offset angle of 45 between each other, number, size, and location of electrohydrodynamic jets with respect to the nozzle position were analyzed using shadowgraphic tomography employing multiplicative algebraic reconstruction technique (MART). Additionally, a flow field inside a cone-shaped liquid (Taylor cone) induced under an electric field was observed using a simultaneous multiplicative algebraic reconstruction technique (SMART), a tomographic method for reconstructing light intensities of particles, combined with three-dimensional cross-correlation. Various velocity fields of circulating flows inside the cone-shaped liquid caused by various physico-chemical properties of liquid were also investigated.

  3. Nanoscale 3D cellular imaging by axial scanning transmission electron tomography

    PubMed Central

    Hohmann-Marriott, Martin F.; Sousa, Alioscka A.; Azari, Afrouz A.; Glushakova, Svetlana; Zhang, Guofeng; Zimmerberg, Joshua; Leapman, Richard D.

    2009-01-01

    Electron tomography provides three-dimensional structural information about supramolecular assemblies and organelles in a cellular context but image degradation, caused by scattering of transmitted electrons, limits applicability in specimens thicker than 300 nm. We show that scanning transmission electron tomography of 1000 nm thick samples using axial detection provides resolution comparable to conventional electron tomography. The method is demonstrated by reconstructing a human erythrocyte infected with the malaria parasite Plasmodium falciparum. PMID:19718033

  4. Evaluation of dacryocystorhinostomy failure with computed tomography and computed tomographic dacryocystography.

    PubMed

    Glatt, H J; Chan, A C; Barrett, L

    1991-10-15

    Five patients with dacryocystorhinostomy failures were examined with computed tomography or computed tomographic dacryocystography. In computed tomographic dacryocystography, radiopaque dye was instilled into the lacrimal sac before computed tomography to show its shape, location, and relation to surrounding structures. Problems with the bony ostium were detected in all five patients. Recurrent nasal polyposis, a retained metallic clip, and an unresected ethmoid air cell were also identified. Computed tomography and computed tomographic dacryocystography provided important information that facilitated reoperation after dacryocystorhinostomy failure. PMID:1928246

  5. Multiple myeloma presenting with a maxillary lesion as the first sign

    PubMed Central

    Joshi, Vajendra; Thayi, Shilpa Ravishankar; Sathyanarayana, Pathalapate; Patil, Prashant; Ahmed, Zaheer

    2015-01-01

    Multiple myeloma is a clonal neoplastic proliferation of terminally differentiated B-lymphocytes involving the skeletal system in a multifocal fashion. Its oral manifestations are less common in the maxilla than in the mandible due to the lower amount of hemopoietic bone marrow in the maxilla. We report the case of a 50-year-old man who presented with a mass in the left maxillary alveolar region with tooth mobility. The mass had become enlarged after the teeth were extracted 15 days previously. Radiographs demonstrated multiple punched-out radiolucent lesions in the skull and pelvic region. Computed tomography images showed a soft tissue density mass in the left maxilla, eroding the floor and walls of the maxillary sinus. Although several analytical techniques were used to characterize the lesion, it was finally confirmed as multiple myeloma through immunohistochemistry. PMID:25793184

  6. High-speed multiple-mode mass-sensing resolves dynamic nanoscale mass distributions

    PubMed Central

    Olcum, Selim; Cermak, Nathan; Wasserman, Steven C.; Manalis, Scott R.

    2015-01-01

    Simultaneously measuring multiple eigenmode frequencies of nanomechanical resonators can determine the position and mass of surface-adsorbed proteins, and could ultimately reveal the mass tomography of nanoscale analytes. However, existing measurement techniques are slow (<1 Hz bandwidth), limiting throughput and preventing use with resonators generating fast transient signals. Here we develop a general platform for independently and simultaneously oscillating multiple modes of mechanical resonators, enabling frequency measurements that can precisely track fast transient signals within a user-defined bandwidth that exceeds 500 Hz. We use this enhanced bandwidth to resolve signals from multiple nanoparticles flowing simultaneously through a suspended nanochannel resonator and show that four resonant modes are sufficient for determining their individual position and mass with an accuracy near 150 nm and 40 attograms throughout their 150-ms transit. We envision that our method can be readily extended to other systems to increase bandwidth, number of modes, or number of resonators. PMID:25963304

  7. Optical homodyne tomography with polynomial series expansion

    SciTech Connect

    Benichi, Hugo; Furusawa, Akira

    2011-09-15

    We present and demonstrate a method for optical homodyne tomography based on the inverse Radon transform. Different from the usual filtered back-projection algorithm, this method uses an appropriate polynomial series to expand the Wigner function and the marginal distribution, and discretize Fourier space. We show that this technique solves most technical difficulties encountered with kernel deconvolution-based methods and reconstructs overall better and smoother Wigner functions. We also give estimators of the reconstruction errors for both methods and show improvement in noise handling properties and resilience to statistical errors.

  8. Frequency multiplexed long range swept source optical coherence tomography

    PubMed Central

    Zurauskas, Mantas; Bradu, Adrian; Podoleanu, Adrian Gh.

    2013-01-01

    We present a novel swept source optical coherence tomography configuration, equipped with acousto-optic deflectors that can be used to simultaneously acquire multiple B-scans originating from different depths. The sensitivity range of the configuration is evaluated while acquiring five simultaneous B-scans. Then the configuration is employed to demonstrate long range B-scan imaging by combining two simultaneous B-scans from a mouse head sample. PMID:23760762

  9. Findings in computerized axial tomography of tuberculous encephalopathy.

    PubMed

    Estaol, B; Lombardo, L; Prez-Ortega, R; Flores-Barroeta, F

    1981-01-01

    A 24 year-old woman with miliary tuberculosis of the lungs, developed a diffuse encephalopathy with signs of increased intracraneal pressure and without meningitis. A CAT scanner disclosed decreased density of the white matter and multiple nodular lesions enhanced with the infusion of contrast media. To our knowledge, this is the first description of the findings in computerized axial tomography of a patient with miliary tuberculosis and hematogenous dissemination associated to diffuse encephalopathy without meningitis. PMID:7247611

  10. Nanoscale scanning transmission electron tomography.

    PubMed

    Midgley, P A; Weyland, M; Yates, T J V; Arslan, I; Dunin-Borkowski, R E; Thomas, J M

    2006-09-01

    Electron tomography enables the study of complex three-dimensional objects with nanometre resolution. In materials science, scanning transmission electron microscopy provides images with minimal coherent diffraction effects and with high atomic number contrast that makes them ideal for electron tomographic reconstruction. In this study, we reviewed the topic of scanning transmission electron microscopy-based tomography and illustrated the power of the technique with a number of examples with critical dimensions at the nanoscale. PMID:17059526

  11. Novel fusion algorithms for medical ultrasound tomography

    NASA Astrophysics Data System (ADS)

    Bashford, Gregory R.; Morse, Jonathan L.; Melander, Jennifer R.

    2004-10-01

    Ultrasound tomography is a bioimaging method that combines the geometry of X-ray computed tomography with the non-ionizing energy of ultrasound. This modality has potential clinical utility in breast cancer screening and diagnosis. In conventional ultrasound tomography, data sets from different interrogation angles are used to reconstruct an estimate of a biomechanical property of the tissue, such as sound velocity, in the form of an image. Here we describe an alternative method of reconstruction using novel algorithms which weight the data based on a "quality" score. The quality score is derived from beamforming characteristics, for example, the weighting of angle-dependent data by its distance from the transmit focal zones. The new approach is that for each data set (taken at a different view angle), the reliability of the data (in the range dimension) is assumed to vary. By fusing (combining) the data based on the quality score, a complete image is formed. In this paper, we describe the construction of a rotational translation stage and tissue-mimicking phantoms that are used in conjunction with a commercial medical ultrasound machine to test our reconstruction algorithms. The new algorithms were found to increase the contrast-to-speckle ratio of simulated cysts by 114% from raw data over a 77% improvement by spatial compounding (averaging), and to decrease wire target width by 54% over a 39% reduction by spatial compounding alone. The new method shows promise as a computationally efficient method of improving contrast and resolution in ultrasound images.

  12. Stellar Multiplicity

    NASA Astrophysics Data System (ADS)

    Duchne, Gaspard; Kraus, Adam

    2013-08-01

    Stellar multiplicity is a ubiquitous outcome of the star-formation process. The frequency and main characteristics of multiple systems, and their dependence on primary mass and environment, are powerful tools to probe this process. Although early attempts were fraught with selection biases and limited completeness, instrumentation breakthroughs in the past two decades now enable robust statistical analyses. In this review, we summarize current empirical knowledge of stellar multiplicity for main sequence stars and brown dwarfs, as well as among populations of pre-main-sequence stars and embedded protostars. Among field objects, the multiplicity rate and breadth of the orbital period distribution are steep functions of the primary mass, whereas the mass ratio distribution is essentially flat for most populations other than the lowest mass objects. The time-variation of the frequency of visual companions follows two parallel, constant tracks corresponding to loose and dense stellar populations, although current observations do not yet distinguish whether initial multiplicity properties are universal or dependent on the physical conditions of the parent cloud. Nonetheless, these quantitative trends provide a rich comparison basis for numerical and analytical models of star formation.

  13. Calibration of electrical impedance tomography

    SciTech Connect

    Daily, W; Ramirez, A

    2000-05-01

    Over the past 10 years we have developed methods for imaging the electrical resistivity of soil and rock formations. These technologies have been called electrical resistance tomography of ERT (e.g. Daily and Owen, 1991). Recently we have been striving to extend this capability to include images of electric impedance--with a new nomenclature of electrical impedance tomography or EIT (Ramirez et al., 1999). Electrical impedance is simply a generalization of resistance. Whereas resistance is the zero frequency ratio of voltage and current, impedance includes both the magnitude and phase relationship between voltage and current at frequency. This phase and its frequency behavior is closely related to what in geophysics is called induced polarization or (Sumner, 1976). Why is this phase or IP important? IP is known to be related to many physical phenomena of importance so that image of IP will be maps of such things as mineralization and cation exchange IP (Marshall and Madden, 1959). Also, it is likely that IP, used in conjunction with resistivity, will yield information about the subsurface that can not be obtained by either piece of information separately. In order to define the accuracy of our technologies to image impedance we have constructed a physical model of known impedance that can be used as a calibration standard. It consists of 616 resistors, along with some capacitors to provide the reactive response, arranged in a three dimensional structure as in figure 1. Figure 2 shows the construction of the network and defines the coordinate system used to describe it. This network of components is a bounded and discrete version of the unbounded and continuous medium with which we normally work (the subsurface). The network has several desirable qualities: (1) The impedance values are known (to the accuracy of the component values). (2) The component values and their 3D distribution is easily controlled. (3) Error associated with electrode noise is eliminated. (4) Each box formed by 12 adjacent components corresponds to a voxel in the finite difference forward model used in the inverse code and this correspondence makes for easy comparison of inversion results and model physical parameters. Using this network we can study the errors associated with the measurement system (called Zombie) separated from the errors introduced by electrode noise. We can also learn details in the behavior of the inversion software (called CR3D) by comparing images and model.

  14. Successful Treatment with Pazopanib for Multiple Lung Metastases of Inguinal Epithelioid Sarcoma: A Case Report.

    PubMed

    Irimura, Sanae; Nishimoto, Kazumasa; Kikuta, Kazutaka; Nakayama, Robert; Susa, Michiro; Horiuchi, Keisuke; Nakamura, Masaya; Matsumoto, Morio; Morioka, Hideo

    2015-01-01

    Epithelioid sarcoma is a rare soft tissue sarcoma and usually resistant to chemotherapy. It has high rates of local recurrence and distant metastasis, and the prognosis after metastasis is poor. We report a case of multiple lung metastases of an epithelioid sarcoma originating in the inguinal area that we treated with the multikinase inhibitor pazopanib. The patient was a 38-year-old male who began to experience discomfort in his left inguinal area. Magnetic resonance imaging showed a tumor extended from the medial aspect of the wing of the left ilium along the iliopsoas muscle to its site of insertion on the femur. The histopathological diagnosis with a biopsy was proximal-type epithelioid sarcoma. Although a positron emission tomography examination showed fluorodeoxyglucose accumulation in the left inguinal tumor, there was no distant metastasis. Wide resection by a combined iliac resection procedure was performed. Twelve months after surgery, computed tomography revealed multiple nodules and a diagnosis of bilateral multiple lung metastases was made. Treatment with pazopanib 800 mg was started. After 2.5 months of treatment, a clear reduction in the size of the pulmonary metastases was shown. Thirty months after the start of pazopanib treatment, most of the metastases have disappeared, and no development of new lesions has been seen. Therefore, it appeared that pazopanib was capable of serving as one of the choices of therapeutic agents that should be taken into consideration for the treatment of advanced epithelioid sarcoma. PMID:26500539

  15. Successful Treatment with Pazopanib for Multiple Lung Metastases of Inguinal Epithelioid Sarcoma: A Case Report

    PubMed Central

    Irimura, Sanae; Nishimoto, Kazumasa; Kikuta, Kazutaka; Nakayama, Robert; Susa, Michiro; Horiuchi, Keisuke; Nakamura, Masaya; Matsumoto, Morio; Morioka, Hideo

    2015-01-01

    Epithelioid sarcoma is a rare soft tissue sarcoma and usually resistant to chemotherapy. It has high rates of local recurrence and distant metastasis, and the prognosis after metastasis is poor. We report a case of multiple lung metastases of an epithelioid sarcoma originating in the inguinal area that we treated with the multikinase inhibitor pazopanib. The patient was a 38-year-old male who began to experience discomfort in his left inguinal area. Magnetic resonance imaging showed a tumor extended from the medial aspect of the wing of the left ilium along the iliopsoas muscle to its site of insertion on the femur. The histopathological diagnosis with a biopsy was proximal-type epithelioid sarcoma. Although a positron emission tomography examination showed fluorodeoxyglucose accumulation in the left inguinal tumor, there was no distant metastasis. Wide resection by a combined iliac resection procedure was performed. Twelve months after surgery, computed tomography revealed multiple nodules and a diagnosis of bilateral multiple lung metastases was made. Treatment with pazopanib 800 mg was started. After 2.5 months of treatment, a clear reduction in the size of the pulmonary metastases was shown. Thirty months after the start of pazopanib treatment, most of the metastases have disappeared, and no development of new lesions has been seen. Therefore, it appeared that pazopanib was capable of serving as one of the choices of therapeutic agents that should be taken into consideration for the treatment of advanced epithelioid sarcoma. PMID:26500539

  16. Uniqueness theorems in bioluminescence tomography.

    PubMed

    Wang, Ge; Li, Yi; Jiang, Ming

    2004-08-01

    Motivated by bioluminescent imaging needs for studies on gene therapy and other applications in the mouse models, a bioluminescence tomography (BLT) system is being developed in the University of Iowa. While the forward imaging model is described by the well-known diffusion equation, the inverse problem is to recover an internal bioluminescent source distribution subject to Cauchy data. Our primary goal in this paper is to establish the solution uniqueness for BLT under practical constraints despite the ill-posedness of the inverse problem in the general case. After a review on the inverse source literature, we demonstrate that in the general case the BLT solution is not unique by constructing the set of all the solutions to this inverse problem. Then, we show the uniqueness of the solution in the case of impulse sources. Finally, we present our main theorem that solid/hollow ball sources can be uniquely determined up to nonradiating sources. For better readability, the exact conditions for and rigorous proofs of the theorems are given in the Appendices. Further research directions are also discussed. PMID:15377096

  17. Computerized tomography calibrator

    NASA Technical Reports Server (NTRS)

    Engel, Herbert P. (Inventor)

    1991-01-01

    A set of interchangeable pieces comprising a computerized tomography calibrator, and a method of use thereof, permits focusing of a computerized tomographic (CT) system. The interchangeable pieces include a plurality of nestable, generally planar mother rings, adapted for the receipt of planar inserts of predetermined sizes, and of predetermined material densities. The inserts further define openings therein for receipt of plural sub-inserts. All pieces are of known sizes and densities, permitting the assembling of different configurations of materials of known sizes and combinations of densities, for calibration (i.e., focusing) of a computerized tomographic system through variation of operating variables thereof. Rather than serving as a phanton, which is intended to be representative of a particular workpiece to be tested, the set of interchangeable pieces permits simple and easy standardized calibration of a CT system. The calibrator and its related method of use further includes use of air or of particular fluids for filling various openings, as part of a selected configuration of the set of pieces.

  18. Rotational magnetic induction tomography

    NASA Astrophysics Data System (ADS)

    Trakic, Adnan; Eskandarnia, Neda; Keong Li, Bing; Weber, Ewald; Wang, Hua; Crozier, Stuart

    2012-02-01

    In magnetic induction tomography (MIT), an array of excitation coils is typically used to apply time-varying magnetic fields to induce eddy currents in the material to be studied. The magnetic fields from the eddy currents are then detected by an array of sensing coils to form an image of passive electromagnetic properties (i.e. conductivity, permittivity and permeability). Increasing the number of transmitters and receivers can provide a better image quality at the expense of a larger and more expensive MIT system. Instead of increasing the number of coils, this study investigates the possibility of rotating a single transmit-receive coil to image the electrical properties of the sample, by emulating an array of 200 transmit-receive coils by time-division multiplexing. Engineering details on the electromechanical design and development of a rotating MIT system are presented. The experimental results indicate that representative images of conductive samples can be obtained at 5 MHz by rotating a single transmit-receive coil.

  19. [Optical coherence tomography].

    PubMed

    von Braunmühl, T

    2015-07-01

    Optical coherence tomography (OCT) was introduced in the 1990s in dermatology and is nowadays established as a noninvasive high-resolution technique for the in vivo evaluation of the skin. To date several studies have been successfully demonstrated the application of OCT for various dermatological questions. The main indication for OCT in the daily practice is the noninvasive diagnosis of nonmelanoma skin cancer such as actinic keratosis and basal cell carcinoma. OCT has also been shown to be a valuable tool in treatment monitoring and evaluation of therapeutic success of noninvasive treatment strategies like topical immune modulators or photodynamic treatment. Other potential applications for OCT include inflammatory diseases, microbial or parasitic infestations of the skin, e.g. scabies mites or onychomycosis. In recent years high-definition OCT devices have been developed that can potentially be used for the evaluation of melanocytic lesions and, due to the higher resolution, for the visualization of intrafollicular demodex mites. Furthermore different commercially available devices offer-in addition to the cross-sectional images-a fast-generated horizontal (en face) imaging mode. With respect to resolution and penetration depth the OCT technique is taking a middle position in comparison to other noninvasive imaging devices in dermatology such as sonography and reflectance confocal microscopy. PMID:25809459

  20. Multiphoton tomography of astronauts

    NASA Astrophysics Data System (ADS)

    König, Karsten; Weinigel, Martin; Pietruszka, Anna; Bückle, Rainer; Gerlach, Nicole; Heinrich, Ulrike

    2015-03-01

    Weightlessness may impair the astronaut's health conditions. Skin impairments belong to the most frequent health problems during space missions. Within the Skin B project, skin physiological changes during long duration space flights are currently investigated on three European astronauts that work for nearly half a year at the ISS. Measurements on the hydration, the transepidermal water loss, the surface structure, elasticity and the tissue density by ultrasound are conducted. Furthermore, high-resolution in vivo histology is performed by multiphoton tomography with 300 nm spatial and 200 ps temporal resolution. The mobile certified medical tomograph with a flexible 360° scan head attached to a mechano-optical arm is employed to measure two-photon autofluorescence and SHG in the volar forearm of the astronauts. Modification of the tissue architecture and of the fluorescent biomolecules NAD(P)H, keratin, melanin and elastin are detected as well as of SHG-active collagen. Thinning of the vital epidermis, a decrease of the autofluoresence intensity, an increase in the long fluorescence lifetime, and a reduced skin ageing index SAAID based on an increased collagen level in the upper dermis have been found. Current studies focus on recovery effects.

  1. Endoscopic Optical Coherence Tomography

    NASA Astrophysics Data System (ADS)

    Zhou, Chao; Fujimoto, James G.; Tsai, Tsung-Han; Mashimo, Hiroshi

    New gastrointestinal (GI) cancers are expected to affect more than 290,200 new patients and will cause more than 144,570 deaths in the United States in 2013 [1]. When detected and treated early, the 5-year survival rate for colorectal cancer increases by a factor of 1.4 [1]. For esophageal cancer, the rate increases by a factor of 2 [1]. The majority of GI cancers begin as small lesions that are difficult to identify with conventional endoscopy. With resolutions approaching that of histopathology, optical coherence tomography (OCT) is well suited for detecting the changes in tissue microstructure associated with early GI cancers. Since the lesions are not endoscopically apparent, however, it is necessary to survey a relatively large area of the GI tract. Tissue motion is another limiting factor in the GI tract; therefore, in vivo imaging must be performed at extremely high speeds. OCT imaging can be performed using fiber optics and miniaturized lens systems, enabling endoscopic OCT inside the human body in conjunction with conventional video endoscopy. An OCT probe can be inserted through the working channel of a standard endoscope, thus enabling depth-resolved imaging of tissue microstructure in the GI tract with micron-scale resolution simultaneously with the endoscopic view (Fig. 68.1).

  2. Cardiovascular Optical Coherence Tomography

    NASA Astrophysics Data System (ADS)

    Yonetsu, Taishi; Villiger, Martin; Bouma, Brett E.; Jang, Ik-Kyung

    The potential of optical coherence tomography (OCT) for intravascular imaging and assessing the microstructure of atherosclerosis was suggested already by Huang et al. at the very beginning of OCT [1]. For ophthalmology, the eye provides a natural window for OCT to image the retinal microstructure, and OCT has rapidly become the standard imaging modality to diagnose retinal disease and assess disease progression and response to therapy [1, 2]. Intravascular imaging is more invasive by nature and requires imaging through a catheter probe. This has triggered the development of advanced fiber-optic OCT systems with compact, rotating fiber probes, to image the vessel by circumferentially scanning the luminal wall [3, 4]. In 1998, we established the first cardiac OCT research group at the Massachusetts General Hospital to explore the clinical applications of OCT. The first imaging of rabbit aorta was reported by Fujimoto et al. [5], followed by the first swine measurements in vivo by Tearney et al. [6], and finally the first assessment of coronary arteries in patients by Jang et al. [7]. The scope of this chapter is to highlight the steps taken to bring intravascular OCT from bench to bedside over the last 15 years. We will give a general description of atherosclerosis and its pathophysiology and the specific technical implementation of OCT for intravascular imaging through a fiber-optic probe. The motivation is to provide sufficient medical details to provide a basic introduction to the terminology, principles, and challenges of intracoronary imaging.

  3. Quantum field tomography

    NASA Astrophysics Data System (ADS)

    Steffens, A.; Riofro, C. A.; Hbener, R.; Eisert, J.

    2014-12-01

    We introduce the concept of quantum field tomography, the efficient and reliable reconstruction of unknown quantum fields based on data of correlation functions. At the basis of the analysis is the concept of continuous matrix product states (cMPS), a complete set of variational states grasping states in one-dimensional quantum field theory. We innovate a practical method, making use of and developing tools in estimation theory used in the context of compressed sensing such as Prony methods and matrix pencils, allowing us to faithfully reconstruct quantum field states based on low-order correlation functions. In the absence of a phase reference, we highlight how specific higher order correlation functions can still be predicted. We exemplify the functioning of the approach by reconstructing randomized cMPS from their correlation data and study the robustness of the reconstruction for different noise models. Furthermore, we apply the method to data generated by simulations based on cMPS and using the time-dependent variational principle. The presented approach is expected to open up a new window into experimentally studying continuous quantum systems, such as those encountered in experiments with ultra-cold atoms on top of atom chips. By virtue of the analogy with the input-output formalism in quantum optics, it also allows for studying open quantum systems.

  4. Doppler Optical Coherence Tomography

    PubMed Central

    Leitgeb, Rainer A.; Werkmeister, René M.; Blatter, Cedric; Schmetterer, Leopold

    2014-01-01

    Optical Coherence Tomography (OCT) has revolutionized ophthalmology. Since its introduction in the early 1990s it has continuously improved in terms of speed, resolution and sensitivity. The technique has also seen a variety of extensions aiming to assess functional aspects of the tissue in addition to morphology. One of these approaches is Doppler OCT (DOCT), which aims to visualize and quantify blood flow. Such extensions were already implemented in time domain systems, but have gained importance with the introduction of Fourier domain OCT. Nowadays phase-sensitive detection techniques are most widely used to extract blood velocity and blood flow from tissues. A common problem with the technique is that the Doppler angle is not known and several approaches have been realized to obtain absolute velocity and flow data from the retina. Additional studies are required to elucidate which of these techniques is most promising. In the recent years, however, several groups have shown that data can be obtained with high validity and reproducibility. In addition, several groups have published values for total retinal blood flow. Another promising application relates to non-invasive angiography. As compared to standard techniques such as fluorescein and indocyanine-green angiography the technique offers two major advantages: no dye is required and depth resolution is required is provided. As such Doppler OCT has the potential to improve our abilities to diagnose and monitor ocular vascular diseases. PMID:24704352

  5. Time-dependent seismic tomography and its application to the Coso geothermal area, 1996-2006

    SciTech Connect

    Julian, B.R.; G.R. Foulger; F. Monastero

    2008-04-01

    Measurements of temporal changes in Earth structure are commonly determined using localearthquake tomography computer programs that invert multiple seismic-wave arrival time data sets separately and assume that any differences in the structural results arise from real temporal variations. This assumption is dangerous because the results of repeated tomography experiments would differ even if the structure did not change, simply because of variation in the seismic ray distribution caused by the natural variation in earthquake locations. Even if the source locations did not change (if only explosion data were used, for example), derived structures would inevitably differ because of observational errors. A better approach is to invert multiple data sets simultaneously, which makes it possible to determine what changes are truly required by the data. This problem is similar to that of seeking models consistent with initial assumptions, and techniques similar to the “damped least squares” method can solve it. We have developed a computer program, dtomo, that inverts multiple epochs of arrival-time measurements to determine hypocentral parameters and structural changes between epochs. We shall apply this program to data from the seismically active Coso geothermal area, California, in the near future. The permanent network operated there by the US Navy, supplemented by temporary stations, has provided excellent earthquake arrival-time data covering a span of more than a decade. Furthermore, structural change is expected in the area as a result of geothermal exploitation of the resource. We have studied the period 1996 through 2006. Our results to date using the traditional method show, for a 2-km horizontal grid spacing, an irregular strengthening with time of a negative VP/VS anomaly in the upper ~ 2 km of the reservoir. This progressive reduction in VP/VS results predominately from an increase of VS with respect to VP. Such a change is expected to result from effects of geothermal operations such as decreasing fluid pressure and the drying of argillaceous minerals such as illite.

  6. Blood oxygenation monitoring by diffuse optical tomography

    SciTech Connect

    Patachia, M; Dutu, D.C.A.; Dumitras, D.C.

    2011-01-24

    Diffuse optical tomography (DOT) makes it possible to reconstruct, in two or three dimensions, the internal structure of the biological tissues based on the distribution of the absorption coefficient and the reduced scattering coefficient, using optical measurements at multiple source - detector positions on the tissue surface. The measurement of the light intensity transmitted through the tissue can be also used to compute the haemoglobin and oxyhaemoglobin concentrations, measuring the selective absorption of the main blood chromophores by near infrared spectroscopy (NIRS). The spectral selectivity of the system and the evaluation of the blood volume and blood oxygenation (BV and OXY distributions), together with the reconstruction of the inner structure of the tissue, can improve the accuracy of early cancer diagnosis, based on the tissue angiogenesis characterisation. (application of lasers and laser-optical methods in life sciences)

  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. Lung vasculature imaging using speckle variance optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Cua, Michelle; Lee, Anthony M. D.; Lane, Pierre M.; McWilliams, Annette; Shaipanich, Tawimas; MacAulay, Calum E.; Yang, Victor X. D.; Lam, Stephen

    2012-02-01

    Architectural changes in and remodeling of the bronchial and pulmonary vasculature are important pathways in diseases such as asthma, chronic obstructive pulmonary disease (COPD), and lung cancer. However, there is a lack of methods that can find and examine small bronchial vasculature in vivo. Structural lung airway imaging using optical coherence tomography (OCT) has previously been shown to be of great utility in examining bronchial lesions during lung cancer screening under the guidance of autofluorescence bronchoscopy. Using a fiber optic endoscopic OCT probe, we acquire OCT images from in vivo human subjects. The side-looking, circumferentially-scanning probe is inserted down the instrument channel of a standard bronchoscope and manually guided to the imaging location. Multiple images are collected with the probe spinning proximally at 100Hz. Due to friction, the distal end of the probe does not spin perfectly synchronous with the proximal end, resulting in non-uniform rotational distortion (NURD) of the images. First, we apply a correction algorithm to remove NURD. We then use a speckle variance algorithm to identify vasculature. The initial data show a vascaulture density in small human airways similar to what would be expected.

  9. Chemical mapping of mammalian cells by atom probe tomography

    PubMed Central

    Narayan, Kedar; Prosa, Ty; Fu, Jing; Kelly, Thomas F; Subramaniam, Sriram

    2012-01-01

    In atom probe tomography (APT), a technique that has been used to determine 3D maps of ion compositions of metals and semiconductors at sub-nanometer resolution, controlled emissions of ions can be induced from needle-shaped specimens in the vicinity of a strong electric field. Detection of these ions in the plane of a position sensitive detector provides two-dimensional compositional information while the sequence of ion arrival at the detector provides information in the third dimension. However, the applicability of APT to imaging unstained cells has not been explored. Here, we report the use of APT to obtain 3D spatial distributions of cellular ions and metabolites from unstained, freeze-dried mammalian cells. Multiple peaks were reliably obtained in the mass spectrum from tips with diameters of ~ 50 nm and heights of ~ 200 nm, with mass-to-charge ratios (m/z) ranging from 1 to 80. Peaks at m/z 12, 23, 28 and 39, corresponding to carbon, sodium, carbonyl and potassium ions respectively, showed distinct patterns of spatial distribution within the cell. Our studies establish that APT could become a powerful tool for mapping the sub-cellular distribution of atomic species, such as labeled metabolites, at 3D spatial resolutions as high as ~ 1 nm. PMID:22245777

  10. An Active Retinal Tracker for Clinical Optical Coherence Tomography Systems

    PubMed Central

    Hammer, Daniel X.; Ferguson, R. Daniel; Paunescu, Lelia Adelina; Beaton, Siobahn; Schuman, Joel S.

    2007-01-01

    An active, hardware-based retinal tracker was built into a clinical optical coherence tomography (OCT) system for stabilization of high-resolution retinal sections. The retinal tracker locks onto common fundus features, detects transverse eye motion via changes in feature reflectance, and positions the OCT diagnostic beam to fixed coordinates on the retina with mirrors driven by a feedback control loop. The system was tested in a full clinical protocol on subjects with normal and glaucomatous eyes. Analysis software was developed to co-align and co-add multiple fundus and OCT images and to extract quantitative information on location of structures in the images. Tracking was highly accurate and reproducible on all but one subject resulting in the ability to scan the same retinal location continually over long periods of time. The results show qualitative improvement in nearly all co-added OCT scans and a reduction in the variance of the position of the optic disc cup edge to less than one pixel. The tracking system can be easily configured for ultrahigh-resolution OCT systems for advanced image modalities. For example, tracking will allow full three-dimensional scans of the retina, the duration of which is currently effectively prohibited by eye motion. PMID:15910111

  11. Automated Segmentation of Soils Using X-ray Tomography

    NASA Astrophysics Data System (ADS)

    Miller, M.; Miller, E.; McKinley, J.

    2014-12-01

    X-ray tomography (CT) has long been a useful tool for three-dimensional imaging of compositionally heterogeneous objects. In the environmental sciences, CT is an efficient tool for the nondestructive inspection of sediment and soil cores. However, in order to extract parameters describing such properties as pore space and solid-phase distribution, the imaged volume must be segmented according to relevant categories. When done manually by image inspection, segmentation produces results that are often inconsistent, and applying the method over multiple images may be impractical. Modern machine learning techniques have been shown to be more accurate than humans at some vision tasks in fields of histology and remote sensing, and those techniques may be useful for environmental samples. We present a technique using deep learning to categorize a tomographic volume into solid and pore regions, while also identifying morphologically similar solid-phase regions within the imaged object. Finally, we show how the composition of these characteristic solid constituents may be estimated by propagating two dimensional XRF data through the segmented volume. This research was funded by the Chemical Imaging Initiative under the Laboratory Directed Research and Development Program at PNNL.

  12. Volume estimation of multidensity nodules with thoracic computed tomography.

    PubMed

    Gavrielides, Marios A; Li, Qin; Zeng, Rongping; Myers, Kyle J; Sahiner, Berkman; Petrick, Nicholas

    2016-01-01

    This work focuses on volume estimation of "multidensity" lung nodules in a phantom computed tomography study. Eight objects were manufactured by enclosing spherical cores within larger spheres of double the diameter but with a different density. Different combinations of outer-shell/inner-core diameters and densities were created. The nodules were placed within an anthropomorphic phantom and scanned with various acquisition and reconstruction parameters. The volumes of the entire multidensity object as well as the inner core of the object were estimated using a model-based volume estimator. Results showed percent volume bias across all nodules and imaging protocols with slice thicknesses [Formula: see text] ranging from [Formula: see text] to 6.6% for the entire object (standard deviation ranged from 1.5% to 7.6%), and within [Formula: see text] to 5.7% for the inner-core measurement (standard deviation ranged from 2.0% to 17.7%). Overall, the estimation error was larger for the inner-core measurements, which was expected due to the smaller size of the core. Reconstructed slice thickness was found to substantially affect volumetric error for both tasks; exposure and reconstruction kernel were not. These findings provide information for understanding uncertainty in volumetry of nodules that include multiple densities such as ground glass opacities with a solid component. PMID:26844235

  13. Multiple linear analysis methods for the quantification of irreversibly binding radiotracers.

    PubMed

    Kim, Su Jin; Lee, Jae Sung; Kim, Yu Kyeong; Frost, James; Wand, Gary; McCaul, Mary E; Lee, Dong Soo

    2008-12-01

    Gjedde-Patlak graphical analysis (GPGA) has commonly been used to quantify the net accumulations (K(in)) of radioligands that bind or are taken up irreversibly. We suggest an alternative approach (MLAIR: multiple linear analysis for irreversible radiotracers) for the quantification of these types of tracers. Two multiple linear regression model equations were derived from differential equations of the two-tissue compartment model with irreversible binding. Multiple linear analysis for irreversible radiotracer 1 has a desirable feature for ordinary least square estimations because only the dependent variable C(T)(t) is noisy. Multiple linear analysis for irreversible radiotracer 2 provides K(in) from direct estimates of the coefficients of independent variables without the mediation of a division operation. During computer simulations, MLAIR1 provided less biased K(in) estimates than the other linear methods, but showed a high uncertainty level for noisy data, whereas MLAIR2 increased the robustness of estimation in terms of variability, but at the expense of increased bias. For real [(11)C]MeNTI positron emission tomography data, both methods showed good correlations, with parameters estimated using the standard nonlinear least squares method. Multiple linear analysis for irreversible radiotracer 2 parametric images showed remarkable image quality as compared with GPGA images. It also showed markedly improved statistical power for voxelwise comparisons than GPGA. The two MLAIR approaches examined were found to have several advantages over the conventional GPGA method. PMID:18628777

  14. Cauda equina syndrome associated with multiple lumbar arachnoid cysts in ankylosing spondylitis: improvement following surgical therapy.

    PubMed Central

    Shaw, P J; Allcutt, D A; Bates, D; Crawford, P J

    1990-01-01

    A case of cauda equina syndrome with multiple lumbar arachnoid cysts complicating ankylosing spondylitis (AS) is described. The value of computerised tomography (CT) and magnetic resonance imaging (MRI) as a non-invasive means of establishing the diagnosis is emphasised. In contrast to previously reported cases the patient showed neurological improvement following surgical therapy. Surgery may be indicated in some patients, particularly when there is nerve root compression by the arachnoid cysts and when the patient is seen early before irreversible damage to the cauda equina has occurred. Images PMID:2292702

  15. Nuclear imaging tomography

    SciTech Connect

    Barfod, J.M.

    1987-03-24

    This patent describes an improved tomographic imaging apparatus of the type having a scintillation detector which is adapted to revolve around a table supported patient for the purpose of obtaining multiple views of the patient for the reconstruction of an axial image. The apparatus comprises: means for moving the table in two dimensions in the plane of the detector motion and in synchrony with the revolving of the detector such that the distance between the patient and the detector is minimized.

  16. Multiple Sclerosis.

    ERIC Educational Resources Information Center

    Plummer, Nancy; Michael, Nancy, Ed.

    This module on multiple sclerosis is intended for use in inservice or continuing education programs for persons who administer medications in long-term care facilities. Instructor information, including teaching suggestions, and a listing of recommended audiovisual materials and their sources appear first. The module goal and objectives are then

  17. (68)Ga-DOTATOC-PET/CT for effective diagnosis and treatment of pancreatic tail gastrinoma with multiple liver metastases: a case report.

    PubMed

    Matsumura, Shinya; Okuyama, Yusuke; Doi, Ryuichiro; Nakao, Ryuta; Urata, Yoji; Yoshida, Norimasa

    2016-01-01

    A 40-year-old man admitted to our hospital with diarrhea underwent abdominal computed tomography (CT) which showed multiple masses in the liver and pancreatic tail. Although there were no abnormal accumulations with fluorodeoxyglucose ((18)F) positron emission tomography (FDG-PET), (68)Ga-DOTATOC-PET/CT detected obvious abnormal accumulations for the both lobes of liver and pancreatic tail tumors. The serum gastrin was markedly high, and liver tumor biopsy demonstrated the presence of malignant cells with round nuclei that were positive for gastrin and somatostatin receptor. The patient was diagnosed with pancreatic tail gastrinoma with multiple liver metastases and treated with octreotide, everolimus, and a proton pump inhibitor which functionally controlled tumor growth. This case demonstrates (68)Ga-DOTATOC-PET/CT as a useful modality for the localization, qualitative diagnosis, and treatment of gastrinoma. PMID:26743558

  18. Imaging the Mantle Transition Zone Using Multimode Waveform Tomography

    NASA Astrophysics Data System (ADS)

    Schaeffer, A. J.; Lebedev, S.

    2014-12-01

    The mantle tranisition zone (TZ) is defined by discontinuities in seismic wave velocities at 410 and 660 km depth, and is thought to play an important role in governing thermo-chemical transport between the upper and lower mantle, in addition to the dynamic evolution of the planet. Furthermore, it has long been at the center of debate between whole-mantle and multi-layered convection models. Although not so well resolved in early tomographic models, improvements in imaging methods and availability of high-quality seismic data have provided increasingly detailed images capable of capturing TZ structure. The variations in isotropic velocity and presence of anisotropy can be used to infer constraints on the thermal and chemical nature of the TZ, and ongoing deformation and transport. For anisotropy in particular, its detection in the deep upper mantle and TZ has remained elusive, with few global models showing significant azimuthal anisotropy at these depths. We utilize automated, multimode waveform inversion to extract structural information from surface, S, and multiple-S waveforms, resulting in a dataset of more than 3/4 of a million successful vertical-component fits. Using a more precise regularization of anisotropy, tuned to honour the amplitude and orientation of anisotropic terms uniformly, we have generated two new models with improved TZ sensitivity to variations in isotropic heterogeneity (SL2013sv), and the detection of azimuthal anisotropy (SL2013svA). For instance high-velocity isotropic anomalies associated with subducted Tethyan lithosphere are detected beneath Eurasia, as well as subducted high-velocity oceanic lithosphere beneath North America. We quantify the requirement for TZ anisotropy through analysis of SL2013svA. Finally we also compare our recent tomography models with other global models (both isotropic and anisotropic), and discuss the implications of their similarities and differences on mantle transition zone properties.

  19. Multiple Retroperitoneal Schwannomas Mimicking Adrenal Tumors

    PubMed Central

    Oishi, Koichi; Itamoto, Toshiyuki; Okimoto, Sho; Nishisaka, Takashi

    2012-01-01

    Schwannomas are benign tumors mostly arising from the head and neck. Retroperitoneal schwannomas are rare. Here we report the case of a 68-year-old woman with multiple retroperitoneal schwannomas. An abdominal computed tomography (CT) scan showed 1 non-enhancing mass with a low-density area, 4.6 cm in diameter, in the left adrenal region and another non-enhancing mass with a low-density area, 2.9 cm in diameter, in the para-aortic region. The patient had regularly undergone CT scans for malignant tumor screening in maintenance dialysis patients. Retrospectively, the 2 tumors had existed in the same regions in previous CT scans and had gradually increased in size. The tumors were completely resected. Pathological diagnosis of both tumors was schwannoma. When a CT scan shows a slowly growing retroperitoneal tumor with a low-density area, schwannoma should be considered. If the tumor increases in size, complete resection should be performed for pathological diagnosis. PMID:22679427

  20. textbf{Tomography of Ionosphere electron density and its abnormity analysis during Wenchuan earthquake }

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoya; Xing, Nan

    2010-05-01

    A multiple-arc method and Kriging interpolation are applied to obtain VTEC as well as DCB using ground-based GPS data. Given by the time variation characteristics of VTEC and DCB, VTEC is calculated every 30 minutes as local variables, and DCB is calculated every day as global variables. Kriging method, taking the spatial information of VTEC into account, is useful to make VTEC more precise and stable. Meanwhile, based on 3-variable spline basis function, we expand electron density into a linear combination of a set of grid points. Tomography of Ionosphere electron density is made by MART. The results show the coherence with CHAMP occultation results. We applied these two ways to process the ground-based GPS data of Yangzi River Triangle Region in May, 2008 when the shocking earthquake happened in Wenchuan. A simple statistic analysis reveals the response of ionosphere to the earthquake and also the abnormal signal occurred before the earthquake.

  1. Study of spatial resolution of proton computed tomography using a silicon strip detector

    NASA Astrophysics Data System (ADS)

    Saraya, Y.; Izumikawa, T.; Goto, J.; Kawasaki, T.; Kimura, T.

    2014-01-01

    Proton computed tomography (CT) is an imaging technique using a high-energy proton beam penetrating the human body and shows promise for improving the quality of cancer therapy with high-energy particle beams because more accurate electron density distribution measurements can be achieved with proton CT. The deterioration of the spatial resolution owing to multiple Coulomb scattering is, however, a crucial issue. The control of the radiation dose and the long exposure time are also problems to be solved. We have developed a prototype system for proton CT with a silicon strip detector and performed a beam test for imaging. The distribution of the electron density has been measured precisely. We also demonstrated an improvement in spatial resolution by reconstructing the proton trajectory. A spatial resolution of 0.45 mm is achieved for a 25-mm-thick polyethylene object. This will be a useful result for upgrading proton CT application for practical use.

  2. Myeloma (multiple)

    PubMed Central

    2006-01-01

    Introduction Multiple myeloma is the most common primary cancer of the bones in adults, representing about 1% of all cancers diagnosed in the US in 2004, and 14% of all haematological malignancies. In the UK, multiple myeloma accounts for 1% of all new cases of cancer diagnosed each year. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatment in people with asymptomatic early stage multiple myeloma (stage I)? What are the effects of first-line treatments in people with advanced stage multiple myeloma (stages II and III)? What are the effect of salvage treatments, or supportive therapy, in people with advanced stage multiple myeloma (stages II and III)? We searched: Medline, Embase, The Cochrane Library and other important databases up to November 2004 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 71 systematic reviews, RCTs, or observational studies that met our inclusion criteria. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: allogenic transplant (non-myeloablative), autologous stem cell transplant (early or late transplantation, double or single, purging of), bisphosphonates, bone marrow stem cells, bortezomib, chemotherapy (combination, conventional dose, intermediate dose plus stem cell rescue, high-dose plus stem cell rescue), combination chemotherapy plus corticosteroids, deferred treatment (in stage I disease), early chemotherapy plus corticosteroids (in stage I disease), epoetin alpha, first-line treatments, infection prophylaxis, interferon, maintenance therapy (in advanced multiple myeloma), melphalan (normal dose, high dose before autologous stem cell transplantation, plus total body irradiation), optimum priming regimen, peripheral blood stem cells, plasmapheresis, salvage therapy regimens, single-agent chemotherapy (adding prednisolone), single-agent chemotherapy (bendamustine, melphalan, cyclophosphamide, lomustine, carmustine) with or without corticosteroid (prednisolone, dexamethasone), syngeneic transplantation, and thalidomide (and derivatives).

  3. Database tomography for commercial application

    NASA Technical Reports Server (NTRS)

    Kostoff, Ronald N.; Eberhart, Henry J.

    1994-01-01

    Database tomography is a method for extracting themes and their relationships from text. The algorithms, employed begin with word frequency and word proximity analysis and build upon these results. When the word 'database' is used, think of medical or police records, patents, journals, or papers, etc. (any text information that can be computer stored). Database tomography features a full text, user interactive technique enabling the user to identify areas of interest, establish relationships, and map trends for a deeper understanding of an area of interest. Database tomography concepts and applications have been reported in journals and presented at conferences. One important feature of the database tomography algorithm is that it can be used on a database of any size, and will facilitate the users ability to understand the volume of content therein. While employing the process to identify research opportunities it became obvious that this promising technology has potential applications for business, science, engineering, law, and academe. Examples include evaluating marketing trends, strategies, relationships and associations. Also, the database tomography process would be a powerful component in the area of competitive intelligence, national security intelligence and patent analysis. User interests and involvement cannot be overemphasized.

  4. Space variant deconvolution for optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Prashanth, R.; Bhattacharya, Shanti

    2011-12-01

    We present a method for mitigating space variant blur occurring in the images acquired using Optical coherence tomography (OCT). The effect of Gaussian beam divergence on the image resolution is analyzed mathematically to develop space dependent two dimensional point spread functions that define the blurring kernel. Two standard deconvolution algorithms are used to deblur the images using the space dependent point spread functions. We show that the deconvolution method is effective in improving the transverse resolution of cross sectional OCT images at regions up to several times as deep as the confocal region of the Gaussian beam.

  5. Volumetric Hall Effect Tomography A Feasibility Study

    PubMed Central

    Wen, Han

    2010-01-01

    Hall effect imaging is an ultrasound-based method of mapping spatial variations in the dielectric constants of an acoustically-uniform sample. This paper presents three-dimensional Hall effect images of phantoms obtained by scanning a single transducer across a two-dimensional grid, effectively simulating two-dimensional phased-array signal reception. The experiments demonstrate the feasibility of volumetric Hall effect tomography and show the advantage of volumetric scans over planar scans. The images reflect several limitations of the current scanning method and point to directions for further hardware development. The inherent limitations of Hall effect imaging are also discussed in light of these results. PMID:10604800

  6. How noise affects quantum detector tomography

    NASA Astrophysics Data System (ADS)

    Wang, Q.; Renema, J. J.; Gaggero, A.; Mattioli, F.; Leoni, R.; van Exter, M. P.; de Dood, M. J. A.

    2015-10-01

    We determine the full photon number response of a NbN superconducting nanowire single photon detector via quantum detector tomography, and the results show the separation of linear, effective absorption efficiency from the internal detection efficiencies. In addition, we demonstrate an error budget for the complete quantum characterization of the detector. We find that for short times, the dominant noise source is shot noise, while laser power fluctuations limit the accuracy for longer timescales. The combined standard uncertainty of the internal detection efficiency derived from our measurements is about 2%.

  7. Nanoscale chemical tomography of buried organic-inorganic interfaces in the chiton tooth.

    PubMed

    Gordon, Lyle M; Joester, Derk

    2011-01-13

    Biological organisms possess an unparalleled ability to control the structure and properties of mineralized tissues. They are able, for example, to guide the formation of smoothly curving single crystals or tough, lightweight, self-repairing skeletal elements. In many biominerals, an organic matrix interacts with the mineral as it forms, controls its morphology and polymorph, and is occluded during mineralization. The remarkable functional properties of the resulting composites-such as outstanding fracture toughness and wear resistance-can be attributed to buried organic-inorganic interfaces at multiple hierarchical levels. Analysing and controlling such interfaces at the nanometre length scale is critical also in emerging organic electronic and photovoltaic hybrid materials. However, elucidating the structural and chemical complexity of buried organic-inorganic interfaces presents a challenge to state-of-the-art imaging techniques. Here we show that pulsed-laser atom-probe tomography reveals three-dimensional chemical maps of organic fibres with a diameter of 5-10?nm in the surrounding nano-crystalline magnetite (Fe(3)O(4)) mineral in the tooth of a marine mollusc, the chiton Chaetopleura apiculata. Remarkably, most fibres co-localize with either sodium or magnesium. Furthermore, clustering of these cations in the fibre indicates a structural level of hierarchy previously undetected. Our results demonstrate that in the chiton tooth, individual organic fibres have different chemical compositions, and therefore probably different functional roles in controlling fibre formation and matrix-mineral interactions. Atom-probe tomography is able to detect this chemical/structural heterogeneity by virtue of its high three-dimensional spatial resolution and sensitivity across the periodic table. We anticipate that the quantitative analysis and visualization of nanometre-scale interfaces by laser-pulsed atom-probe tomography will contribute greatly to our understanding not only of biominerals (such as bone, dentine and enamel), but also of synthetic organic-inorganic composites. PMID:21228873

  8. Using Acceleration Records as Diffuse Fields for Tomography of the Valley of Mexico City: Synthetic Results

    NASA Astrophysics Data System (ADS)

    Baena, M.; Perton, M.; Molina-Villegas, J. C.; Sanchez-Sesma, F. J.

    2013-12-01

    In order to improve the understanding of the seismic response of Mexico City Valley, we have proposed to perform a tomography study of the seismic wave velocities. For that purpose, we used a collection of acceleration seismograms (corresponding to earthquakes with magnitudes ranging from 4.5 to 8.1 and various epicentral distances to the City) recorded since 1985 in 83 stations distributed across the Valley. The H/V spectral ratios (obtained from average autocorrelations) strongly suggest these movements belong to a 3D generalized diffuse field. Thus, we interpret that cross-correlations between the signals of station pairs are proportional to the imaginary part of the corresponding Green function. Finally, the dispersion curves are constructed from the Green function which lead to the tomography. Other tomographies have already been made around the world using either the seismic coda or seismic noise. We used instead the ensemble of many earthquakes from distant sources that have undergone multiple scattering by the heterogeneities of the Earth and assume the wave fields are equipartitioned. The purpose of the present study is to describe the different steps of the data processing by using synthetic models. The wave propagation within an alluvial basin is simulated using the Indirect Boundary Element Method (IBEM) in 2D configuration for the propagation of P and SV waves. The theoretical Green function for a station pair is obtained by placing a unit force at one station and a receiver at the other. The valley illumination is composed by incoming waves which are simulated using distant independent sources and several diffractors. Data process is validated by the correct retrieval the theoretical Green function. We present here the in-plane Green function for the P-SV case and show the dispersion curves constructed from the cross-correlations compared with analytic results for a layer over a half-space. ACKNOWLEDGEMENTS. This study is partially supported by AXA Research Fund and by DGAPA-UNAM under Project IN104712.

  9. Quantitative photoacoustic tomography

    PubMed Central

    Yuan, Zhen; Jiang, Huabei

    2009-01-01

    In this paper, several algorithms that allow for quantitative photoacoustic reconstruction of tissue optical, acoustic and physiological properties are described in a finite-element method based framework. These quantitative reconstruction algorithms are compared, and the merits and limitations associated with these methods are discussed. In addition, a multispectral approach is presented for concurrent reconstructions of multiple parameters including deoxyhaemoglobin, oxyhaemoglobin and water concentrations as well as acoustic speed. Simulation and in vivo experiments are used to demonstrate the effectiveness of the reconstruction algorithms presented. PMID:19581254

  10. Classification and 3D averaging with missing wedge correction in biological electron tomography

    PubMed Central

    Bartesaghi, A.; Sprechmann, P.; Liu, J.; Randall, G.; Sapiro, G.; Subramaniam, S.

    2008-01-01

    Strategies for the determination of 3D structures of biological macromolecules using electron crystallography and single-particle electron microscopy utilize powerful tools for the averaging of information obtained from 2D projection images of structurally homogeneous specimens. In contrast, electron tomographic approaches have often been used to study the 3D structures of heterogeneous, one-of-a-kind objects such as whole cells where image-averaging strategies are not applicable. Complex entities such as cells and viruses, nevertheless, contain multiple copies of numerous macromolecules that can individually be subjected to 3D averaging. Here we present a complete framework for alignment, classification, and averaging of volumes derived by electron tomography that is computationally efficient and effectively accounts for the missing wedge that is inherent to limited-angle electron tomography. Modeling the missing data as a multiplying mask in reciprocal space we show that the effect of the missing wedge can be accounted for seamlessly in all alignment and classification operations. We solve the alignment problem using the convolution theorem in harmonic analysis, thus eliminating the need for approaches that require exhaustive angular search, and adopt an iterative approach to alignment and classification that does not require the use of external references. We demonstrate that our method can be successfully applied for 3D classification and averaging of phantom volumes as well as experimentally obtained tomograms of GroEL where the outcomes of the analysis can be quantitatively compared against the expected results. PMID:18440828

  11. Research of inverse synthetic aperture imaging lidar based on filtered back-projection tomography technique

    NASA Astrophysics Data System (ADS)

    Liu, Zhi-chao; Yang, Jin-hua

    2014-07-01

    In order to obtain clear two-dimensional image under the conditions without using heterodyne interferometry by inverse synthetic aperture lidar(ISAL), designed imaging algorithms based on filtered back projection tomography technique, and the target "A" was reconstructed with simulation algorithm by the system in the turntable model. Analyzed the working process of ISAL, and the function of the reconstructed image was given. Detail analysis of the physical meaning of the various parameters in the process of echo data, and its parameters affect the reconstructed image. The image in test area was reconstructed by the one-dimensional distance information with filtered back projection tomography technique. When the measured target rotated, the sum of the echo light intensity at the same distance was constituted by the different position of the measured target. When the total amount collected is large enough, multiple equations can be solved change. Filtered back-projection image of the ideal image is obtained through MATLAB simulation, and analyzed that the angle intervals affected the reconstruction of image. The ratio of the intensity of echo light and loss light affected the reconstruction of image was analyzed. Simulation results show that, when the sampling angle is smaller, the resolution of the reconstructed image of measured target is higher. And the ratio of the intensity of echo light and loss light is greater, the resolution of the reconstructed image of measured target is higher. In conclusion after some data processing, the reconstructed image basically meets be effective identification requirements.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Fern, 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.

  14. Quantum state tomography with incomplete data: Maximum entropy and variational quantum tomography

    NASA Astrophysics Data System (ADS)

    Gonçalves, D. S.; Lavor, C.; Gomes-Ruggiero, M. A.; Cesário, A. T.; Vianna, R. O.; Maciel, T. O.

    2013-05-01

    Whenever we do not have an informationally complete set of measurements, the estimate of a quantum state cannot be uniquely determined. In this case, among the density matrices compatible with the available data, the one commonly preferred is the one which is the most uncommitted to the missing information. This is the purpose of the maximum entropy estimation (MaxEnt) and the variational quantum tomography (VQT). Here, we propose a variant of VQT and show its relationship with MaxEnt methods in quantum tomographies with an incomplete set of measurements. We prove their equivalence in the case of eigenbasis measurements, and through numerical simulations we stress their similar behavior. Hence, in the modified VQT formulation we have an estimate of a quantum state as unbiased as in MaxEnt and with the benefit that VQT can be more efficiently solved by means of linear semidefinite programs.

  15. 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.

  16. Combined computed tomography and fluorodeoxyglucose positron emission tomography in the diagnosis of prosthetic valve endocarditis: a case series

    PubMed Central

    2014-01-01

    Background The diagnosis of prosthetic valve endocarditis is challenging. The gold standard for prosthetic valve endocarditis diagnosis is trans-esophageal echocardiography. However, trans-esophageal echocardiography may result in negative findings or yield images difficult to differentiate from thrombus in patients with prosthetic valve endocarditis. Combined computed tomography and fluorodeoxyglucose positron emission tomography is a potentially promising diagnostic tool for several infectious conditions and it has also been employed in patients with prosthetic valve endocarditis but data are still scant. Case presentations We reviewed the charts of 6 patients with prosthetic aortic valves evaluated for suspicion of prosthetic valve endocarditis, at two different hospital, over a 3-year period. We found 3 patients with early-onset PVE cases and blood cultures yielding Pseudomonas aeruginosa, Staphylococcus epidermidis and Staphylococcus lugdunensis, respectively; and 3 late-onset cases in the remaining 3 patients with isolation in the blood of Streptococcus bovis, Candida albicans and P. aeruginosa, respectively. Initial trans-esophageal echocardiography was negative in all the patients, while fluorodeoxyglucose positron emission tomography showed images suspicious for prosthetic valve endocarditis. In 4 out of 6 patients valve replacement was done with histology confirming the prosthetic valve endocarditis diagnosis. After an adequate course of antibiotic therapy fluorodeoxyglucose positron emission tomography showed resolution of prosthetic valve endocarditis in all the patients. Conclusion Our experience confirms the potential role of fluoroseoxyglucose positron emission tomography in the diagnosis and follow-up of prosthetic valve endocarditis. PMID:24418206

  17. Positron emission tomography in oncology

    SciTech Connect

    Not Available

    1988-04-08

    This report describes the current and potential uses of positron emission tomography in clinical medicine and research related to oncology. Assessment will be possible of metabolism and physiology of tumors and their effects on adjacent tissues. Specific probes are likely to be developed for target sites on tumors, including monoclonal antibodies and specific growth factors that recognize tumors. To date, most oncological applications of positron emission tomography tracers have been qualitative; in the future, quantitative metabolic measurements should aid in the evaluation of tumor biology and response to treatment.

  18. Electron tomography of dislocation structures

    SciTech Connect

    Liu, G.S.; House, S.D.; Kacher, J.; Tanaka, M.; Higashida, K.; Robertson, I.M.

    2014-01-15

    Recent developments in the application of electron tomography for characterizing microstructures in crystalline solids are described. The underlying principles for electron tomography are presented in the context of typical challenges in adapting the technique to crystalline systems and in using diffraction contrast imaging conditions. Methods for overcoming the limitations associated with the angular range, the number of acquired images, and uniformity of image contrast are introduced. In addition, a method for incorporating the real space coordinate system into the tomogram is presented. As the approach emphasizes development of experimental solutions to the challenges, the solutions developed and implemented are presented in the form of examples.

  19. Multiple sclerosis

    PubMed Central

    Nylander, Alyssa; Hafler, David A.

    2012-01-01

    Multiple sclerosis (MS) is a multifocal demyelinating disease with progressive neurodegeneration caused by an autoimmune response to self-antigens in a genetically susceptible individual. While the formation and persistence of meningeal lymphoid follicles suggest persistence of antigens to drive the continuing inflammatory and humoral response, the identity of an antigen or infectious agent leading to the oligoclonal expansion of B and T cells is unknown. In this review we examine new paradigms for understanding the immunopathology of MS, present recent data defining the common genetic variants underlying disease susceptibility, and explore how improved understanding of immune pathway disruption can inform MS prognosis and treatment decisions. PMID:22466660

  20. Multiple myeloma

    PubMed Central

    Rajkumar, S. Vincent

    2008-01-01

    Multiple myeloma is a clonal plasma cell malignancy that accounts for slightly more than 10% of all hematologic cancers. In this paper, we present a historically focused review of the disease, from the description of the first case in 1844 to the present. The evolution of drug therapy and stem-cell transplantation for the treatment of myeloma, as well as the development of new agents, is discussed. We also provide an update on current concepts of diagnosis and therapy, with an emphasis on how treatments have emerged from a historical perspective after certain important discoveries and the results of experimental studies. PMID:18332230

  1. Multiple sclerosis.

    PubMed

    Files, Daniel Kane; Jausurawong, Tani; Katrajian, Ruba; Danoff, Robert

    2015-06-01

    Multiple sclerosis (MS) is a chronic, debilitating disease that can have devastating effects. Presentation varies widely in symptoms, pace, and progression. In addition to a thorough history and physical examination, diagnostic tools required to diagnose MS and exclude other diagnoses include MRI, evoked potential testing, and cerebrospinal fluid analysis. Although the disease is not curable presently, quality of life can be improved by minimizing the frequency and severity of disease burden. Disease modification, symptom management, preservation of function, and treatment of psychosocial issues are paramount to enhance the quality of life for the patient affected with MS. PMID:25979578

  2. Multi-signal FIB/SEM tomography

    NASA Astrophysics Data System (ADS)

    Giannuzzi, Lucille A.

    2012-06-01

    Focused ion beam (FIB) milling coupled with scanning electron microscopy (SEM) on the same platform enables 3D microstructural analysis of structures using FIB for serial sectioning and SEM for imaging. Since FIB milling is a destructive technique, the acquisition of multiple signals from each slice is desirable. The feasibility of collecting both an inlens backscattered electron (BSE) signal and an inlens secondary electron (SE) simultaneously from a single scan of the electron beam from each FIB slice is demonstrated. The simultaneous acquisition of two different SE signals from two different detectors (inlens vs. Everhart-Thornley (ET) detector) is also possible. Obtaining multiple signals from each FIB slice with one scan increases the acquisition throughput. In addition, optimization of microstructural and morphological information from the target is achieved using multi-signals. Examples of multi-signal FIB/SEM tomography from a dental implant will be provided where both material contrast from the bone/ceramic coating/Ti substrate phases and porosity in the ceramic coating will be characterized.

  3. Portable 3-D computed tomography system

    SciTech Connect

    Phillips, D. H.; Davis, A. W.; Keating, S. C.; Claytor, T. N.

    2001-06-01

    Through a Cooperative Research and Development Agreement between Los Alamos National Laboratory and HYTEC, Inc., a portable 3-D Computed Tomography (CT) system has been developed that dramatically reduces the overall complexity and time-to-completion for performing CT studies. The system incorporates an amorphous silicon flat-panel detector, coupled motion control and state of the art software to produce high quality CT results. All alignment, image calibration and radiation exposure monitoring is handled in software, thereby, eliminating the need for precise mechanical positioning during setup or a highly stable source of radiation. The image acquisition hardware occupies a minimal 30-inch x 48-inch footprint and is mounted on a portable cart for transportation between multiple X-ray sites. The software is built on the Windows NT/2K operating system for maximum flexibility in today's industry, and offers an unprecedented user interface designed for technicians and operators who have minimal computer training. Multiple reconstruction methods (parallel, fan and cone beam) are provided and can be run in a parallel-processed mode on any number of Windows NT/2K computers to decrease reconstruction time. Visualization software offers 2-D and 3-D viewing including slice animation and volume rendering of entire objects.

  4. Multiple ectopic hepatocellular carcinomas arising in the abdominal cavity.

    PubMed

    Miyake, Toru; Hoshino, Seiichiro; Yoshida, Yoichiro; Aisu, Naoya; Tanimura, Syu; Hisano, Satoshi; Kuno, Nobuaki; Sohda, Tetsuro; Sakisaka, Shotaro; Yamashita, Yuichi

    2012-09-01

    Ectopic hepatocellular carcinoma (HCC) is a very rare clinical entity that is defined as HCC arising from extrahepatic liver tissue. This report presents a case of ectopic multiple HCC arising in the abdominal cavity. A 42-year-old otherwise healthy male presented with liver dysfunction at a general health checkup. Both HCV antibody and hepatitis B surface antigen were negative. Laboratory examination showed elevations in serum alpha-fetoprotein and PIVKA-II. Ultrasonography and computed tomography revealed multiple nodular lesions in the abdominal cavity with ascites without a possible primary tumor. Exploratory laparoscopy was performed, which revealed bloody ascites and multiple brown nodular tumors measuring approximately 10 mm in size that were disseminated on the perineum and mesentery. A postoperative PET-CT scan was performed but it did not reveal any evidence of a tumor in the liver. The tumors resected from the peritoneum were diagnosed as HCC. The present case of HCC was thought to have possibly developed from ectopic liver on the peritoneum or mesentery. PMID:23139654

  5. Anisotropic resistivity tomography

    NASA Astrophysics Data System (ADS)

    Herwanger, J. V.; Pain, C. C.; Binley, A.; de Oliveira, C. R. E.; Worthington, M. H.

    2004-08-01

    Geophysical tomographic techniques have the potential to remotely detect and characterize geological features, such as fractures and spatially varying lithologies, by their response to signals passed through these features. Anisotropic behaviour in many geological materials necessitates the generalization of tomographic methods to include anisotropic material properties in order to attain high-quality images of the subsurface. In this paper, we present a finite element (FE) based direct-current electrical inversion method to reconstruct the conductivity tensor at each node point of a FE mesh from electrical resistance measurements. The inverse problem is formulated as a functional optimization and the non-uniqueness of the electrical inverse problem is overcome by adding penalty terms for structure and anisotropy. We use a modified Levenberg-Marquardt method for the functional optimization and the resulting set of linear equation is solved using pre-conditioned conjugate gradients. The method is tested using both synthetic and field experiments in cross-well geometry. The acquisition geometry for both experiments uses a cross-well experiment at a hard-rock test site in Cornwall, southwest England. Two wells, spaced at 25.7 m, were equipped with electrodes at a 1 m spacing at depths from 21-108 m and data were gathered in pole-pole geometry. The test synthetic model consists of a strongly anisotropic and conductive body underlain by an isotropic resistive formation. Beneath the resistive formation, the model comprises a moderately anisotropic and moderately conductive half-space, intersected by an isotropic conductive layer. This model geometry was derived from the interpretation of a seismic tomogram and available geological logs and the conductivity values are based on observed conductivities. We use the test model to confirm the ability of the inversion scheme to recover the (known) true model. We find that all key features of the model are recovered. However, the inversion model is smoother than the true model and the difference in absolute value of anisotropy and conductivity between features is slightly underestimated. Using an anisotropic conductivity distribution aggravates the problem of non-uniqueness of the solution of the inverse electrical problem. This problem can be overcome by applying appropriate structural and anisotropy constraints. We find that running a suite of inversions with varying constraint levels and subsequent examination of the results (including the inspection of residual maps) offers a viable method for choosing appropriate numerical values for the imposed constraints. Inversion of field data reveals a strongly anisotropic subsurface with marked spatial variations of both magnitude of anisotropy and conductivity. Average conductivities range from 0.001 S m-1 (= 1000 ? m) to 0.003 S m-1 (= 333 ? m) and anisotropy values range from 0 per cent to more than 300 per cent. As an independent test of the reliability of the structures revealed by anisotropic electric tomography, anisotropic seismic traveltime tomograms were calculated. We find a convincing structural agreement between the two independently derived images. Areas of high electric anisotropy coincide with seismically anisotropic areas and we observe an anticorrelation between electric conductivity and seismic velocity. Both observations are consistent with anisotropy anomalies caused by fracturing or layering.

  6. On the limitations of interstation distances in ambient noise tomography

    NASA Astrophysics Data System (ADS)

    Luo, Yinhe; Yang, Yingjie; Xu, Yixian; Xu, Hongrui; Zhao, Kaifeng; Wang, Kai

    2015-05-01

    Ambient noise tomography (ANT) has recently become a popular tomography method to study crustal structures thanks to its unique capability to extract short-period surface waves. Empirically, in order to reliably measure surface wave dispersion curves from time-domain cross-correlations, interstation distances between a pair of stations have to be longer than two/three wavelengths. This requirement imposed a strong constraint on the use of ANT at the long-period end at local- and regional-scale tomography studies. In this study, we use ambient noise data from USArray/Transportable Array recorded during 2007-2012 to investigate whether dispersion measurements from cross-correlations of ambient noise at short interstation distances are consistent with those at long distances and whether the short-path dispersion measurements can be used in tomography, especially in local- and regional-scale tomography. Our results show that: (1) surface wave phase velocity dispersion curves measured by a frequency-time analysis technique (FTAN) from time-domain cross-correlations are consistent with those measured by a spectral method tracing the zero crossings of the real part of cross-spectrum functions in frequency domain; (2) dispersion measurements from time-domain cross-correlations with short interstation distances, up to only one wavelength, are consistent with and also reliable as those with interstation distances longer than three wavelengths and (3) these short-path measurements can be included in ANT to improve path coverage and resolution.

  7. Complex differential variance algorithm for optical coherence tomography angiography

    PubMed Central

    Nam, Ahhyun S.; Chico-Calero, Isabel; Vakoc, Benjamin J.

    2014-01-01

    We describe a complex differential variance (CDV) algorithm for optical coherence tomography based angiography. The algorithm exploits both the intensity and phase changes of optical coherence tomography (OCT) signals from flowing blood to achieve high vascular contrast, and also intrinsically reject undesirable phase signals originating from small displacement axial bulk tissue motion and instrument synchronization errors. We present this algorithm within a broader discussion of the properties of OCT signal dynamics. The performance of the algorithm is compared against two other existing algorithms using both phantom measurements and in vivo data. We show that the algorithm provides better contrast for a given number of measurements and equivalent spatial averaging. PMID:25426313

  8. Heliospheric Tomography from IPS Data at 140 MHz

    NASA Astrophysics Data System (ADS)

    Mejia-Ambriz, J. C.; Jackson, B. V.; Gonzalez-Esparza, A.; Buffington, A.

    2014-12-01

    Interplanetary scintillation (IPS) from radio telescopes provides data to study density and velocity evolution of the solar wind and heliospheric disturbances. A tomography program developed at the University of California, San Diego, makes 3D reconstructions and forecasts of the inner heliosphere dynamics from IPS results. For the first time we incorporate 140 MHz IPS results from the MEXican Array Radio Telescope (MEXART) into the tomography program. We show that MEXART data complement observations from other radio-systems located at different longitudes, thus providing more complete heliospheric coverage.

  9. Design of a muon tomography system with a plastic scintillator and wavelength-shifting fiber arrays

    NASA Astrophysics Data System (ADS)

    Jo, Woo Jin; Kim, Hyun-Il; An, Su Jung; Lee, Chae Young; Baek, Cheol-Ha; Chung, Yong Hyun

    2013-12-01

    Recently, monitoring nuclear materials to avoid nuclear terrorism has become an important area of national security. It can be difficult to detect gamma rays from nuclear material because they are easily shielded by shielding material. Muon tomography using multiple -Coulomb scattering derived from muons can be utilized to detect special nuclear materials (SNMs) such as uranium-235 and plutonium-239. We designed a muon tomography system composed of four detector modules. The incident and scattered muon tracks can be calculated by two top and two bottom detectors, respectively. 3D tomographic images are obtained by extracting the crossing points of muon tracks with a point-of-closest-approach algorithm. The purpose of this study was to optimize the muon tomography system using Monte Carlo simulation code. The effects of the geometric parameters of the muon tomography system on material Z-discrimination capability were simulated and evaluated.

  10. Asymptomatic Multiple Myeloma Presenting as a Nodular Hepatic Lesion: A Case Report and Review of the Literature

    PubMed Central

    Huang, Hans; Bazerbachi, Fateh; Mesa, Hector; Gupta, Pankaj

    2015-01-01

    Background Plasma cell myeloma is the most common primary bone malignancy in adults. However, liver involvement in the form of an initial and asymptomatic nodular plasmacytoma is exceedingly rare. Case Report A 64-year-old male was found to have a right hepatic lobe nodule on a routine abdominal ultrasound prior to bariatric surgery. Liver biopsy revealed a plasma cell neoplasm that, given the location of the lesion, was favored to represent a lymphoma with prominent plasmacytic differentiation. Positron emission tomography (PET) demonstrated a hypermetabolic hepatic mass and identified multiple destructive bony lesions. Biopsy of a clavicular lesion revealed sheets of plasma cells and confirmed the diagnosis of multiple myeloma. The patient underwent 6 cycles of chemotherapy with cyclophosphamide, bortezomib, and dexamethasone before transitioning to lenalidomide and dexamethasone because of early disease progression. Although the patient had International Staging System I (low-risk) disease, his disease demonstrated an aggressive clinical course and resistance to multiple lines of therapy. Conclusion Extramedullary nodular hepatic plasmacytoma is exceedingly rare. Nevertheless, extramedullary plasmacytomas should be included in the differential diagnosis of patients with indistinct hepatic lesions visualized on computed tomography scan, especially if PET scans show associated bony lesions. In general, extramedullary plasmacytomas are a poor prognostic sign and a harbinger of an aggressive clinical course in the context of multiple myeloma.

  11. Multiple myeloma.

    PubMed

    Harousseau, Jean-Luc; Shaughnessy, John; Richardson, Paul

    2004-01-01

    High-dose therapy with stem cell transplantation (SCT) and novel targeted therapies (thalidomide, its more potent analogues, and bortezomib) represent two approaches for overcoming resistance of multiple myeloma (MM) cells to conventional therapies. While it is now clear that dose-intensification improves the outcome in younger patients, long-term remissions are obtained in a minority of patients. Therefore, the impact of novel agents as part of front-line therapy is the objective of ongoing trials. Gene expression profiling (GEP) will help to improve the management of MM not only by identifying prognostic subgroups but also by defining molecular pathways that are associated with these subgroups and that are possible targets for future therapies. In Section I, Dr. John Shaughnessy describes recent data obtained with GEP of CD138-purified plasma cells from patients with MM. His group has already shown that overexpression of the Wnt signaling inhibitor DKK1 by MM plasma cells blocks osteoblast differentiation and contributes to the development of osteolytic bone lesions. Recent data allow identification of four subgroups of MM in which GEP is highly correlated not only with different clinical characteristics and outcome but also with different cytogenetic abnormalities. In addition, abnormal expression of only three genes (RAN, ZHX-2, CHC1L) is associated with rapid relapses. In the context of intensive therapy with tandem autotransplantations, this model appears to be more powerful than current prognostic models based on standard biologic variables and cytogenetics. Understanding why the dysregulation of these three genes is associated with a more aggressive behavior of the disease will help to define new therapeutic strategies. In Section II, Dr. Jean-Luc Harousseau presents recent results achieved with tandem autologous SCT (ASCT) and with reduced intensity conditioning (RIC) allogeneic SCT. ASCT is now considered as the standard of care in patients up to 65 years of age. The IFM (Intergroupe Francophone du Myelome) has recently shown that double ASCT is superior to single ASCT. Current results of three other randomized trials confirm that double ASCT is superior, at least in terms of event-free survival. However, patients with poor prognostic features do poorly even after tandem ASCT. Strategies to further improve the outcome of ASCT include more intensive therapies and the use of novel agents such as thalidomide and immunomodulatory analogs (IMiDs) or bortezomib. Results of allogeneic SCT remain disappointing in MM even with T cell-depleted grafts. Preliminary results of a strategy combining ASCT to reduce tumor burden and RIC allogeneic SCT are encouraging, although the follow-up is still short. However, again, patients with chromosome 13 deletions have poor results with RIC. Longer follow-up of ongoing multicentric studies will help to clarify the indications of RIC. In Section III, Dr. Paul Richardson summarizes current knowledge of novel targeted therapies in MM. A better understanding of interactions between MM cells and bone marrow stromal cells and of the signaling cascades whereby cytokines mediate proliferation, survival, drug resistance and migration of MM cells provide the rationale for testing novel agents in relapsed/refractory MM. Increased angiogenesis coupled with the known anti-angiogenesis activity of thalidomide justified its use in refractory MM. The remarkable responses initially achieved prompted a number of clinical studies in different indications and the development of more potent IMIDs. Among them CC-5013 (Revlimid) has been tested in Phase I/II studies and a randomized Phase III study has just been completed. Blockade of NF-kappa B using the proteasome inhibitor bortezomib (Velcade) may mediate anti-MM activity by inhibiting interleukin (IL)-6 production in stromal cells and other mechanisms of action have been shown in preclinical studies. Based on the promising results of the Phase II trial, a large randomized trial of bortezomib versus dexamethasone has been completed. Studies of bortezomib combined with other drugs are ongoing. Arsenic trioxide has a number of properties showing that it targets MM cells interacting with the microenvironment. Clinical studies are ongoing as well. Other agents in MM have already been or will probably be translated soon from the bench to the bedside. PMID:15561686

  12. Computed tomography demonstration of subarachnoid-pleural fistula.

    PubMed

    Hicken, P; Martin, J; Hakanson, S

    1990-08-01

    A persistent left pleural effusion caused diagnostic difficulty in a young girl, 2 years after a road accident had rendered her paraplegic. Eventually, after instillation of a contrast medium into the pleural fluid, computed tomography showed a fistulous communication between the subarachnoid and pleural spaces at the level in the dorsal spine where trauma had occurred. PMID:2207780

  13. Probable Syphilitic Aortitis Documented by Positron Emission Tomography.

    PubMed

    Joseph Davey, Dvora; Acosta, Lourdes Del Rocio Carrera; Gupta, Pawan; Konda, Kelika A; Caceres, Carlos F; Klausner, Jeffrey D

    2016-03-01

    Positron emission tomography (PET) has been used to aid in diagnosis of inflammatory and infectious disease. We describe the case of a patient with early latent syphilis with increased metabolic activity along the aorta detected via PET, suggesting probable aortitis. Three months after treatment, the PET showed apparent resolution of the aortitis. PMID:26859808

  14. Iterative Reconstruction Methods for Hybrid Inverse Problems in Impedance Tomography

    NASA Astrophysics Data System (ADS)

    Hoffmann, Kristoffer; Knudsen, Kim

    2014-11-01

    For a general formulation of hybrid inverse problems in impedance tomography the Picard and Newton iterative schemes are adapted and four iterative reconstruction algorithms are developed. The general problem formulation includes several existing hybrid imaging modalities such as current density impedance imaging, magnetic resonance electrical impedance tomography, and ultrasound modulated electrical impedance tomography, and the unified approach to the reconstruction problem encompasses several algorithms suggested in the literature. The four proposed algorithms are implemented numerically in two dimensions and the properties of the algorithms and the implementations are investigated, both theoretically and on simulated data obtained from a numerical phantom. The numerical results show similarities and differences between the proposed algorithms, and they justify that the choice of algorithm should be based on a theoretical analysis of the underlying inverse problem.

  15. Dictionary-learning-based reconstruction method for electron tomography.

    PubMed

    Liu, Baodong; Yu, Hengyong; Verbridge, Scott S; Sun, Lizhi; Wang, Ge

    2014-01-01

    Electron tomography usually suffers from so-called missing wedge artifacts caused by limited tilt angle range. An equally sloped tomography (EST) acquisition scheme (which should be called the linogram sampling scheme) was recently applied to achieve 2.4-angstrom resolution. On the other hand, a compressive sensing inspired reconstruction algorithm, known as adaptive dictionary based statistical iterative reconstruction (ADSIR), has been reported for X-ray computed tomography. In this paper, we evaluate the EST, ADSIR, and an ordered-subset simultaneous algebraic reconstruction technique (OS-SART), and compare the ES and equally angled (EA) data acquisition modes. Our results show that OS-SART is comparable to EST, and the ADSIR outperforms EST and OS-SART. Furthermore, the equally sloped projection data acquisition mode has no advantage over the conventional equally angled mode in this context. PMID:25104167

  16. Gate Set Tomography of a 3D Transmon Qubit

    NASA Astrophysics Data System (ADS)

    Guo, Yudan; Novikov, Sergey; Greenbaum, Daniel; Skinner, Andrew; Palmer, B. S.

    2015-03-01

    Quantum gate set tomography is a recently developed tool for characterizing quantum gates that does not suffer from the inaccuracies inherent in standard quantum process tomography. We present the results of a gate set tomography (GST) experiment done on a superconducting 3D transmon qubit. π and π / 2 rotations over the x- and y-axes were used as the initial calibrated gates. We performed linear inversion on data from a 4-fiducial experiment to obtain an initial tomographic estimate, which was then used as the starting point for a maximum likelihood procedure. The calibrated gates all achieved fidelity above 98%, which was further verified by randomized benchmarking. The robustness of GST was also examined by introducing errors deliberately. We show that GST with maximum likelihood estimation is able to discern errors due to a mixed initial state, as well as due to a tilted rotation axis in our gate operation.

  17. 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.

  18. A new algorithm of ionospheric tomographytwo-step solution

    NASA Astrophysics Data System (ADS)

    Wen, Debao

    The inherent non-ideal geometry of ground-based global navigation satellite system (GNSS) observation stations distribution results in limited-angle tomographic inverse problems that are ill-posed. To cope with the above problem, a new tomographic algorithm, which is called two-step solution (TSS), is presented in this paper. In the new method, the electron density can be estimated by using two steps: 1) Phillips smoothing method (PSM) is first used to resolve the ill-posed problem in ionospheric tomography system; 2) The "coarse" solution of PSM is then input as the initial value of multiplicative algebraic reconstruction technique (MART) and improved by iterative mode. Numerical simulation experiment demonstrates that the two-step solution is feasible to GNSS-based ionospheric tomography and superior to PSM or MART alone.

  19. Image reconstruction in photoacoustic tomography involving layered acoustic media.

    PubMed

    Schoonover, Robert W; Anastasio, Mark A

    2011-06-01

    Photoacoustic tomography (PAT), also known as thermoacoustic or optoacoustic tomography, is a rapidly emerging biomedical imaging technique that combines optical image contrast with ultrasound detection principles. Most existing reconstruction algorithms for PAT assume the object of interest possesses homogeneous acoustic properties. The images produced by such algorithms can contain significant distortions and artifacts when the object's acoustic properties are spatially variant. In this work, we establish an image reconstruction formula for PAT applications in which a planar detection surface is employed and the to-be-imaged optical absorber is embedded in a known planar layered acoustic medium. The reconstruction formula is exact in a mathematical sense and accounts for multiple acoustic reflections between the layers of the medium. Computer-simulation studies are conducted to demonstrate and investigate the proposed method. PMID:21643397

  20. 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

  1. Low-cost diffuse optical tomography for the classroom

    NASA Astrophysics Data System (ADS)

    Minagawa, Taisuke; Zirak, Peyman; Weigel, Udo M.; Kristoffersen, Anna K.; Mateos, Nicolas; Valencia, Alejandra; Durduran, Turgut

    2012-10-01

    Diffuse optical tomography (DOT) is an emerging imaging modality with potential applications in oncology, neurology, and other clinical areas. It allows the non-invasive probing of the tissue function using relatively inexpensive and safe instrumentation. An educational laboratory setup of a DOT system could be used to demonstrate how photons propagate through tissues, basics of medical tomography, and the concepts of multiple scattering and absorption. Here, we report a DOT setup that could be introduced to the advanced undergraduate or early graduate curriculum using inexpensive and readily available tools. The basis of the system is the LEGO Mindstorms NXT platform which controls the light sources, the detectors (photo-diodes), a mechanical 2D scanning platform, and the data acquisition. A basic tomographic reconstruction is implemented in standard numerical software, and 3D images are reconstructed. The concept was tested and developed in an educational environment that involved a high-school student and a group of post-doctoral fellows.

  2. 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.

  3. Spectroscopy in Magnetic Resonance Tomography

    SciTech Connect

    Verkhoglazova, E. V.; Kupriyanov, D. A.

    2007-11-26

    The magnetic resonance (MR) tomography is giving general picture of concentration and distribution of nuclei and spectroscopy analysis adds information about metabolites of examined nuclei. Such data enable more detailed diagnosis of diseases and treatment follow-up to be carried out in vivo.

  4. 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)

  5. Motion Compensation in Emission Tomography

    NASA Astrophysics Data System (ADS)

    van den Hoff, Jrg; Langner, Jens

    With the ever-improving spatial resolution available in single photon emission computed tomography (SPECT) and, especially, in positron emission tomography (PET), the unavoidable organ and subject motion is becoming one of the dominant factors limiting the practically achievable spatial resolution in the tomographic images. Moreover, uncorrected subject motion can lead to potentially severe image artifacts and compromise the quantitative integrity of the data. The latter is of special importance in PET where quantitative assessment of tracer concentrations is commonplace both in static investigations via so-called standardized uptake values (SUVs) and in dynamic studies aiming at tracer kinetic modeling and quantification of the corresponding transport constants. Correction of the heart-cycle-related motion in cardiac applications has a long tradition and is covered extensively in the literature. Correction of breathing-related organ motion in emission tomography, however, has drawn considerable interest only in recent years in the context of oncological PET. This is mainly due to the demands of therapy response monitoring and radiation treatment planning. The third important area is high-precision motion correction of random head motion in brain investigations. In this chapter, we give an overview of the methods employed to minimize - and possibly eliminate - the motion influence in emission tomography.

  6. Computed tomography of intracranial ependymomas

    SciTech Connect

    Swartz, J.D.; Zimmerman, R.A.; Bilaniuk, L.T.

    1982-04-01

    Twenty-six patients with ependymoma were evaluated by computed tomography (CT) over a period of 5 1/2 years. The usual CT appearance was an isodense, partially calcified mass, capable of contrast enhancement, occurring in the posterior fossa (73%) in an infant or child (77%). Outcome remains poor despite modern diagnostic and therapeutic methods.

  7. Nonabsorbable suture granuloma mimicking ovarian cancer recurrence at combined positron emission tomography/computed tomography evaluation: a case report

    PubMed Central

    2014-01-01

    Introduction This is the first case of suture granuloma mimicking isolated ovarian cancer relapse. Only six analogous cases have been previously reported in other malignancies. Case presentation We report the case of a 44-year-old Caucasian woman with partially platinum-sensitive ovarian cancer in which radiological features, including computed tomography and combined 18F-fluorodeoxyglucose-positron emission tomography/computed tomography, were strongly suggestive of isolated cancer relapse in her right subdiaphragmatic region. Laparoscopic examination resulted negative, but was not completely suitable due to widespread adhesive syndrome. The laparotomy for secondary cytoreductive surgery and biopsy of the suspected area showed inflammatory granuloma caused by nonabsorbable propylene suture, without evidence of neoplastic cells. Moreover, unexpected peritoneal carcinosis was found. Conclusions This evidence suggests that clinical details about previous surgical procedures are necessary for adequate interpretation. Although much progress has been made in imaging techniques, especially in the promising field of combined 18F-fluorodeoxyglucose positron emission tomography/computed tomography, these procedures should be still thoroughly investigated in order to promptly rule out tumor recurrence and avoid unnecessary surgery. PMID:24942653

  8. Quantum tomography of atomic spins via continuous measurement

    NASA Astrophysics Data System (ADS)

    Riofrio, Carlos; Deutsch, Ivan; Smith, Aaron; Anderson, Brian; Jessen, Poul

    2011-05-01

    Quantum tomography can be carried out by continuous weak measurement on an ensemble of identically prepared systems that are controlled so that an informationally complete measurement record is obtained (PRL 95, 030402 (2005)). In comparison to traditional tomography carried out by strong measurement on repeatedly prepared systems, this method has the advantage of being fast and accurate, as seen in experiments that reconstruct the density matrix of spins of ultracold atoms (PRL 95, 030402 (2005)). We show how our procedure can be extended to perform tomography on quantum states stored in the 16 dimensional ground-electronic hyperfine manifolds (F=3, F=4) of an ensemble of 133Cs atoms controlled by microwaves and radio-frequency magnetic fields and discuss our efforts, challenges, and results of the undergoing experimental implementation. Quantum tomography can be carried out by continuous weak measurement on an ensemble of identically prepared systems that are controlled so that an informationally complete measurement record is obtained (PRL 95, 030402 (2005)). In comparison to traditional tomography carried out by strong measurement on repeatedly prepared systems, this method has the advantage of being fast and accurate, as seen in experiments that reconstruct the density matrix of spins of ultracold atoms (PRL 95, 030402 (2005)). We show how our procedure can be extended to perform tomography on quantum states stored in the 16 dimensional ground-electronic hyperfine manifolds (F=3, F=4) of an ensemble of 133Cs atoms controlled by microwaves and radio-frequency magnetic fields and discuss our efforts, challenges, and results of the undergoing experimental implementation. Supported by NSF PHY-0903692 and PHY-0903953.

  9. Positron Emission Tomography and Single-Photon Emission Computed Tomography in Central Nervous System Drug Development

    PubMed Central

    Brooks, David J.

    2005-01-01

    Summary: In this review, the value of functional imaging [positron emission tomography (PET)/single-photon emission computed tomography (SPECT)] in drug development is considered. Radionuclide imaging can help establish the diagnosis of neurodegenerative disorders where this is in doubt and provides a potential biomarker for following drug effects on disease progression. PET and SPECT can help understand mechanisms of disease and determine the functional effects of therapeutic approaches on neurotransmission and metabolism. Synthesizing radiotracer analogs of novel drugs can provide proof of principle that these agents reach their enzyme or receptor targets and delineate their regional brain distribution. If such radiotracers do not prove to have ideal properties for imaging, the concept of microdosing potentially allows multiple other drug analogs to be tested with less stringent regulatory requirements than for novel medicinals. Finally, PET tracers can provide receptor and enzyme active site dose occupancy profiles, thereby guiding dosage selection for phase 1 and phase 2 trials. The eventual hope is that radiotracer imaging will provide a surrogate marker for drug efficacy, although this has yet to be realized, and progress the concept of personalized medicine where receptor/enzyme binding profiles help predict therapeutic outcome. PMID:15897947

  10. Sparsity-driven autofocus for multipass SAR tomography

    NASA Astrophysics Data System (ADS)

    Muirhead, F.; Mulgrew, B.; Woodhouse, I. H.; Greig, D.

    2015-10-01

    Synthetic aperture radar (SAR) systems produce high resolution, two dimensional imaging of areas of environmental interest. SAR interferometry and tomography enables these techniques to extend to three dimensional imaging by exploiting multiple SAR images with diversity in space and time. These techniques require accurate phase information over multiple images as the data is extremely sensitive to deviations from the reference track, therefore to enable interferometry and tomography an accurate autofocus solution is required. This paper investigates phase errors resulting from navigational uncertainties in multipass spotlight SAR imaging and uses techniques from the field of compressive sensing to achieve an autofocus solution. The proposed algorithm builds on previous autofocus work by expanding it to the multipass case and jointly recovers phase errors for all images simultaneously, making it extremely useful for interferometry and tomography techniques. The algorithm described uses pixels that are stable in all SAR images to gain an autofocus solution as these are the pixels that are the focus for analysis using tomography. This is unlike conventional autofocus, which just works on an image-by-image basis. The tools of compressive sensing can be used to concurrently select pixels for bright image elements that are stable and coherent over all images, as these pixels are sparse in the image domain, and calculate the phase errors present in each pass. Using the multipass data after autofocus, height distributions for scatterers in single pixels are determined for simulated forest scenes at X-band. The performance of the autofocus algorithm is examined through numerical simulations and is also applied to real data collected from Selex ES's airborne, X-band, experimental SAR system. The experimental results demonstrate that the algorithm effectively achieves an autofocus solution. By finding the vertical distribution of two scatterers in a single pixel over simulated forestry images we can determine if compressive sensing can be utilized to gain information on scatterers below the canopy at X-band in future studies.

  11. [Multiple apheresis].

    PubMed

    Coffe, C

    2007-05-01

    Multiple apheresis makes it possible to obtain at least two labile blood components from a single donor using a cell separator. It can be either multicomponent apheresis leading to the preparation of at least two different blood component types or red blood cell apheresis providing two identical red blood cell concentrates. These techniques available in addition to whole blood donation, are modifying collection strategies in many Etablissements Français du Sang and will contribute to improve stock logistics in the future. In areas with insufficient stock, these procedures will help achieve blood component self-sufficiency. The author first describes the principle underlying different--current or future--techniques as well as their advantages and drawbacks. He finally addresses the potential impact of these processes on the evolution of blood collection and the advantages to be gained. PMID:17521944

  12. Superposition principle and waveform tomography. How well can we do ?

    NASA Astrophysics Data System (ADS)

    Masson, Y.; Romanowicz, B. A.; French, S. W.

    2011-12-01

    Seismic waves recorded at the Earth's surface contain information on the Earth's internal structure gathered along the wave's propagation paths. When the seismic source responsible for the different records is known, waveform tomography can be used to image the spatial distribution of the elastic properties within the Earth. To achieve high resolution, approximate expressions of the wave field obtained using normal mode perturbation theory have progressively been replaced by exact numerical solutions. Numerical methods, such as the Spectral Element Method (SEM) can indeed model the effects of strong lateral heterogeneity of different scales with a greater accuracy. However, these methods are computationally expensive and the cost of the inversion is usually increasing proportionally to the number of seismic events or seismic sources for which the associated recorded wave field needs to be computed. In seismology, the superposition principle also known as superposition property, states that the seismic response at a given place and time caused by two or more seismic sources is the sum of the responses which would have been caused by each source individually. Using this principle, it is possible to sum the seismic records associated with multiple events to create a new set of records that would have been recorded if all seismic events occurred simultaneously. With this new data set, the computational cost of waveform tomography is greatly reduced as the synthetic wave field only needs to be computed once to model all the records in the data set. Thus, taking advantage of the superposition principle seems very appealing for waveform tomography. Initial tests at the global scale with long period waveforms have shown promising results (Capdeville et al., 2005). However, the limitations on structure recovery have not been fully explored, some information on the Earth's structure contained in the original data set (before summation) is likely be lost when the different records are summed and a trade off between computational efficiency and model accuracy exists. This is likely even more problematic for regional scale problems. Some processing techniques such a phase encoding (Romero et al., 2000) have been successfully used to improve the quality of migrated images obtained using shots summation in exploration geophysics. To investigate the possible advantage of using the superposition principle for the regional scale, we performed multiple inversions, with and without summation of sources, using synthetic seismic records computed for known artificial models. We observed that in many situations, waveform tomography with source summation produces significantly better images of the propagation medium than classical travel time tomography. However, taking advantage of the superposition principle is not always efficient and can produce erroneous results in some cases. Numerical benchmark tests are presented along with a discussion on the optimal setup for regional scale tomography using source summation.

  13. [Multiple intracranial arteriovenous malformation].

    PubMed

    Gelabert-Gonzlez, Miguel; Santin-Amo, Jos Mara; Romn-Pena, Paula; Vzquez Herrero, Fernando

    2015-01-01

    Multiple cerebral arteriovenous malformations (AVMs) are thought to be exceedingly rare lesions and have usually been reported as single cases. The incidence of multiple cerebral AVMs in major series ranges from 0.3% to 9% and, in the majority of cases, these malformations are associated with other vascular anomalies of the brain or soft tissues. We report a 62-year-old woman that presented with a left temporal haemorrhage. Angiography showed 3 AVMs located in the left temporal lobe, left cerebellar hemisphere and right temporal lobe. The lesions were treated with radiosurgery. PMID:25596643

  14. Technetium-99m methylene diphosphonate uptake in the brachialis muscle hematoma in a patient with prostate cancer and coagulation disorder mimicking bone metastasis evaluated by single-photon emission tomography-computed tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Mohanan, Vyshakh; Madhavan, Devdas; Shinto, Ajit Sugunan

    2013-01-01

    We report a case of 79-year-old male with prostate cancer and coagulation disorder presented with left shoulder pain. He underwent bone scintigraphy to rule out metastasis, which showed intense foci of tracer activity in the left axilla. Hybrid single-photon emission tomography-computed tomography (SPECT/CT) of the shoulder region localized tracer uptake to the left brachialis muscle hematoma. PMID:24379534

  15. Technetium-99m methylene diphosphonate uptake in the brachialis muscle hematoma in a patient with prostate cancer and coagulation disorder mimicking bone metastasis evaluated by single-photon emission tomography-computed tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Mohanan, Vyshakh; Madhavan, Devdas; Shinto, Ajit Sugunan

    2013-10-01

    We report a case of 79-year-old male with prostate cancer and coagulation disorder presented with left shoulder pain. He underwent bone scintigraphy to rule out metastasis, which showed intense foci of tracer activity in the left axilla. Hybrid single-photon emission tomography-computed tomography (SPECT/CT) of the shoulder region localized tracer uptake to the left brachialis muscle hematoma. PMID:24379534

  16. A rare case of nonenhancing primary central nervous system lymphoma mimic multiple sclerosis

    PubMed Central

    Chen, Hai; Dong, Huiqing

    2015-01-01

    Primary central nervous system lymphoma (PCNSL) is reported to have increased in the last decades. Early diagnosis is crucial for proper management of this tumor. We report a case of a 48-year-old man who was initially diagnosed with multiple sclerosis. Magnetic resonance imaging of the brain revealed multiple lesions with hypersignals in the bilateral basal ganglia and brain stem in T2-weighted image and non-enhancement, while positron emission tomography showed a low uptake of 18F-fluorodeoxyglucose in the affected brain, indicative of demyelination. However, this individual was correctly diagnosed with PCNSL after biopsy and further histological analysis. Primary central nervous system lymphoma must be considered even when nonenhancing, diffuse lesions are seen on MRI. A visible tumor on imaging is essential to ensure an early brain biopsy and histological diagnosis. PMID:26492120

  17. Lung postmortem autopsy revealing extramedullary involvement in multiple myeloma causing acute respiratory distress syndrome.

    PubMed

    Ravinet, Aurlie; Perbet, Sbastien; Guize, Romain; Lemal, Richard; Gurin, Renaud; Gayraud, Guillaume; Aliane, Jugurtha; Tremblay, Aymeric; Pascal, Julien; Ledoux, Albane; Chaleteix, Carine; Dechelotte, Pierre; Bay, Jacques-Olivier; Bazin, Jean-Etienne; Constantin, Jean-Michel

    2014-01-01

    Pulmonary involvement with multiple myeloma is rare. We report the case of a 61-year-old man with past medical history of chronic respiratory failure with emphysema, and a known multiple myeloma (Durie and Salmon stage III B and t(4;14) translocation). Six months after diagnosis and first line of treatment, he presented acute dyspnea with interstitial lung disease. Computed tomography showed severe bullous emphysema and diffuse, patchy, multifocal infiltrations bilaterally with nodular character, small bilateral pleural effusions, mediastinal lymphadenopathy, and a known lytic lesion of the 12th vertebra. He was treated with piperacillin-tazobactam, amikacin, oseltamivir, and methylprednisolone. Finally, outcome was unfavourable. Postmortem analysis revealed diffuse and nodular infracentimetric infiltration of the lung parenchyma by neoplastic plasma cells. Physicians should be aware that acute respiratory distress syndrome not responding to treatment of common causes could be a manifestation of the disease, even with negative BAL or biopsy and could be promptly treated with salvage therapy. PMID:25165587

  18. Lung Postmortem Autopsy Revealing Extramedullary Involvement in Multiple Myeloma Causing Acute Respiratory Distress Syndrome

    PubMed Central

    Ravinet, Aurlie; Perbet, Sbastien; Guize, Romain; Gurin, Renaud; Gayraud, Guillaume; Aliane, Jugurtha; Tremblay, Aymeric; Pascal, Julien; Ledoux, Albane; Chaleteix, Carine; Dechelotte, Pierre; Bay, Jacques-Olivier; Bazin, Jean-Etienne; Constantin, Jean-Michel

    2014-01-01

    Pulmonary involvement with multiple myeloma is rare. We report the case of a 61-year-old man with past medical history of chronic respiratory failure with emphysema, and a known multiple myeloma (Durie and Salmon stage III B and t(4;14) translocation). Six months after diagnosis and first line of treatment, he presented acute dyspnea with interstitial lung disease. Computed tomography showed severe bullous emphysema and diffuse, patchy, multifocal infiltrations bilaterally with nodular character, small bilateral pleural effusions, mediastinal lymphadenopathy, and a known lytic lesion of the 12th vertebra. He was treated with piperacillin-tazobactam, amikacin, oseltamivir, and methylprednisolone. Finally, outcome was unfavourable. Postmortem analysis revealed diffuse and nodular infracentimetric infiltration of the lung parenchyma by neoplastic plasma cells. Physicians should be aware that acute respiratory distress syndrome not responding to treatment of common causes could be a manifestation of the disease, even with negative BAL or biopsy and could be promptly treated with salvage therapy. PMID:25165587

  19. Limited-angle tomography for analyzer-based phase-contrast X-ray imaging

    PubMed Central

    Majidi, Keivan; Wernick, Miles N; Li, Jun; Muehleman, Carol; Brankov, Jovan G

    2014-01-01

    Multiple-Image Radiography (MIR) is an analyzer-based phase-contrast X-ray imaging method (ABI), which is emerging as a potential alternative to conventional radiography. MIR simultaneously generates three planar parametric images containing information about scattering, refraction and attenuation properties of the object. The MIR planar images are linear tomographic projections of the corresponding object properties, which allows reconstruction of volumetric images using computed tomography (CT) methods. However, when acquiring a full range of linear projections around the tissue of interest is not feasible or the scanning time is limited, limited-angle tomography techniques can be used to reconstruct these volumetric images near the central plane, which is the plane that contains the pivot point of the tomographic movement. In this work, we use computer simulations to explore the applicability of limited-angle tomography to MIR. We also investigate the accuracy of reconstructions as a function of number of tomographic angles for a fixed total radiation exposure. We use this function to find an optimal range of angles over which data should be acquired for limited-angle tomography MIR (LAT-MIR). Next, we apply the LAT-MIR technique to experimentally acquired MIR projections obtained in a cadaveric human thumb study. We compare the reconstructed slices near the central plane to the same slices reconstructed by CT-MIR using the full angular view around the object. Finally, we perform a task-based evaluation of LAT-MIR performance for different numbers of angular views, and use template matching to detect cartilage in the refraction image near the central plane. We use the signal-to-noise ratio of this test as the detectability metric to investigate an optimum range of tomographic angles for detecting soft tissues in LAT-MIR. Both results show that there is an optimum range of angular view for data acquisition where LAT-MIR yields the best performance, comparable to CT-MIR only if one considers volumetric images near the central plane and not the whole volume. PMID:24898008

  20. Limited-angle tomography for analyzer-based phase-contrast x-ray imaging.

    PubMed

    Majidi, Keivan; Wernick, Miles N; Li, Jun; Muehleman, Carol; Brankov, Jovan G

    2014-07-01

    Multiple-image radiography (MIR) is an analyzer-based phase-contrast x-ray imaging method, which is emerging as a potential alternative to conventional radiography. MIR simultaneously generates three planar parametric images containing information about scattering, refraction and attenuation properties of the object. The MIR planar images are linear tomographic projections of the corresponding object properties, which allows reconstruction of volumetric images using computed tomography (CT) methods. However, when acquiring a full range of linear projections around the tissue of interest is not feasible or the scanning time is limited, limited-angle tomography techniques can be used to reconstruct these volumetric images near the central plane, which is the plane that contains the pivot point of the tomographic movement. In this work, we use computer simulations to explore the applicability of limited-angle tomography to MIR. We also investigate the accuracy of reconstructions as a function of number of tomographic angles for a fixed total radiation exposure. We use this function to find an optimal range of angles over which data should be acquired for limited-angle tomography MIR (LAT-MIR). Next, we apply the LAT-MIR technique to experimentally acquired MIR projections obtained in a cadaveric human thumb study. We compare the reconstructed slices near the central plane to the same slices reconstructed by CT-MIR using the full angular view around the object. Finally, we perform a task-based evaluation of LAT-MIR performance for different numbers of angular views, and use template matching to detect cartilage in the refraction image near the central plane. We use the signal-to-noise ratio of this test as the detectability metric to investigate an optimum range of tomographic angles for detecting soft tissues in LAT-MIR. Both results show that there is an optimum range of angular view for data acquisition where LAT-MIR yields the best performance, comparable to CT-MIR only if one considers volumetric images near the central plane and not the whole volume. PMID:24898008

  1. Limited-angle tomography for analyzer-based phase-contrast x-ray imaging

    NASA Astrophysics Data System (ADS)

    Majidi, Keivan; Wernick, Miles N.; Li, Jun; Muehleman, Carol; Brankov, Jovan G.

    2014-07-01

    Multiple-image radiography (MIR) is an analyzer-based phase-contrast x-ray imaging method, which is emerging as a potential alternative to conventional radiography. MIR simultaneously generates three planar parametric images containing information about scattering, refraction and attenuation properties of the object. The MIR planar images are linear tomographic projections of the corresponding object properties, which allows reconstruction of volumetric images using computed tomography (CT) methods. However, when acquiring a full range of linear projections around the tissue of interest is not feasible or the scanning time is limited, limited-angle tomography techniques can be used to reconstruct these volumetric images near the central plane, which is the plane that contains the pivot point of the tomographic movement. In this work, we use computer simulations to explore the applicability of limited-angle tomography to MIR. We also investigate the accuracy of reconstructions as a function of number of tomographic angles for a fixed total radiation exposure. We use this function to find an optimal range of angles over which data should be acquired for limited-angle tomography MIR (LAT-MIR). Next, we apply the LAT-MIR technique to experimentally acquired MIR projections obtained in a cadaveric human thumb study. We compare the reconstructed slices near the central plane to the same slices reconstructed by CT-MIR using the full angular view around the object. Finally, we perform a task-based evaluation of LAT-MIR performance for different numbers of angular views, and use template matching to detect cartilage in the refraction image near the central plane. We use the signal-to-noise ratio of this test as the detectability metric to investigate an optimum range of tomographic angles for detecting soft tissues in LAT-MIR. Both results show that there is an optimum range of angular view for data acquisition where LAT-MIR yields the best performance, comparable to CT-MIR only if one considers volumetric images near the central plane and not the whole volume.

  2. Electron Tomography: Seeing Atoms in Three Dimensions

    SciTech Connect

    Arslan, Ilke; Stach, Eric A.

    2012-11-01

    Our eyes - a parallel lens system - have the phenomenal ability to observe and "reconstruct" the three-dimensional world, relaying a 3-D image to our brains. Imaging of the nanoworld is best done with electrons rather than photons because of their lower wavelengths and higher resolution. The advent of aberration-correction has led to transmission electron microscopes with sub-Angstrom resolution that can resolve single atoms. Yet, no matter what detector is used, the resulting images are only two-dimensional projections of three-dimensional objects. Electron tomography is a technique that allows reconstruction of the three-dimensional structure and morphology of nanomaterials from such projections. X-ray tomography has been used in many branches of science for nearly half a century, and in the biological sciences electron tomography has been a powerful tool for understanding ultrastructure. However, for many years crystalline materials posed a challenge to electron tomography because diffraction contrast (a change in intensity in the image at particular crystal orientations) creates artifacts in the 3-D reconstruction. In 2003, with advances in scanning transmission electron microscopy, Midgley and colleagues obtained the first electron tomograms of crystalline materials. Shortly thereafter, Arslan et al. showed that the spatial resolution could be improved to 1 nm in all three spatial dimensions and visualized the formation of faceted 3.5-nm quantum dots embedded in a Si matrix. However, with that work existing reconstruction algorithms appeared to have reached their limit. To attain a resolution of 1 nm, a total of 140 images over 78 degrees of tilt were needed. Writing in Nature Materials, Goris et al. now report a novel algorithm for 3-D reconstruction of the atomic structure of free-standing Au nanorods, using only four projection images. I.A. acknowledges collaboration with J.D. Roehling, K.J. Batenburg, B.C. Gates and A. Katz for Figure 1, supported in part by the DOE BES DE-SC0005822, and in part by the LDRD program at PNNL. The Pacific Northwest National Laboratory is operated by Battelle under contract DE-AC05-76RL01830.

  3. Eigenvector decomposition of full-spectrum x-ray computed tomography

    NASA Astrophysics Data System (ADS)

    Gonzales, Brian J.; Lalush, David S.

    2012-03-01

    Energy-discriminated x-ray computed tomography (CT) data were projected onto a set of basis functions to suppress the noise in filtered back-projection (FBP) reconstructions. The x-ray CT data were acquired using a novel x-ray system which incorporated a single-pixel photon-counting x-ray detector to measure the x-ray spectrum for each projection ray. A matrix of the spectral response of different materials was decomposed using eigenvalue decomposition to form the basis functions. Projection of FBP onto basis functions created a de facto image segmentation of multiple contrast agents. Final reconstructions showed significant noise suppression while preserving important energy-axis data. The noise suppression was demonstrated by a marked improvement in the signal-to-noise ratio (SNR) along the energy axis for multiple regions of interest in the reconstructed images. Basis functions used on a more coarsely sampled energy axis still showed an improved SNR. We conclude that the noise-resolution trade off along the energy axis was significantly improved using the eigenvalue decomposition basis functions.

  4. An interesting case of polyostotic fibrous dysplasia: The pirate sign evaluated with Tc-99m methylene diphosphonate single-photon emission computed tomography/computerized tomography

    PubMed Central

    Harisankar, Chidambaram Natarajan Balasubramanian; Bhattacharya, Anish; Bhadada, Sanjay Kumar; Kamaleshwaran, Koramadai Karuppusamy; Mittal, Bhagwant Rai

    2011-01-01

    Polyostotic fibrous dysplasia is a rare progressive benign disorder of the bone. Bone scintigraphy is extremely useful in the initial evaluation for identifying the extent of disease. We report a case presenting with pathological fracture of the shaft of the right femur. After treatment of the fracture, bone scintigraphy revealed involvement of multiple bones including the skull and facial bones. The utility of single-photon emission computed tomography/computerized tomography in the evaluation of the extent of skull base involvement is highlighted. PMID:21969780

  5. Clinical multiphoton FLIM tomography

    NASA Astrophysics Data System (ADS)

    König, Karsten

    2012-03-01

    This paper gives an overview on current clinical high resolution multiphoton fluorescence lifetime imaging in volunteers and patients. Fluorescence lifetime imaging (FLIM) in Life Sciences was introduced in Jena/Germany in 1988/89 based on a ZEISS confocal picosecond dye laser scanning microscope equipped with a single photon counting unit. The porphyrin distribution in living cells and living tumor-bearing mice was studied with high spatial, temporal, and spectral resolution. Ten years later, time-gated cameras were employed to detect dental caries in volunteers based on one-photon excitation of autofluorescent bacteria with long fluorescence lifetimes. Nowadays, one-photon FLIM based on picosecond VIS laser diodes are used to study ocular diseases in humans. Already one decade ago, first clinical twophoton FLIM images in humans were taken with the certified clinical multiphoton femtosecond laser tomograph DermaInspectTM. Multiphoton tomographs with FLIM modules are now operating in hospitals at Brisbane, Tokyo, Berlin, Paris, London, Modena and other European cities. Multiple FLIM detectors allow spectral FLIM with a temporal resolution down to 20 ps (MCP) / 250 ps (PMT) and a spectral resolution of 10 nm. Major FLIM applications include the detection of intradermal sunscreen and tattoo nanoparticles, the detection of different melanin types, the early diagnosis of dermatitis and malignant melanoma, as well as the measurement of therapeutic effects in pateints suffering from dermatitis. So far, more than 1,000 patients and volunteers have been investigated with the clinical multiphoton FLIM tomographs DermaInspectTM and MPTflexTM.

  6. Carrier multiplication in graphene.

    PubMed

    Winzer, Torben; Knorr, Andreas; Malic, Ermin

    2010-12-01

    Graphene as a zero-bandgap semiconductor is an ideal model structure to study the carrier relaxation channels, which are inefficient in conventional semiconductors. In particular, it is of fundamental interest to address the question whether Auger-type processes significantly influence the carrier dynamics in graphene. These scattering channels bridge the valence and conduction band allowing carrier multiplication, a process that generates multiple charge carriers from the absorption of a single photon. This has been suggested in literature for improving the efficiency of solar cells. Here we show, based on microscopic calculations within the density matrix formalism, that Auger processes do play an unusually strong role for the relaxation dynamics of photoexcited charge carriers in graphene. We predict that a considerable carrier multiplication takes place, confirming the potential of graphene as a new material for high-efficiency photodevices. PMID:21053963

  7. Optical Coherence Tomography Velocimetry with Complex Fluids

    NASA Astrophysics Data System (ADS)

    Malm, A.; Waigh, T. A.; Jaradat, S.; Tomlin, R.

    2015-04-01

    We present recent results obtained with an Optical Coherence Tomography Velocimetry technique. An optical interferometer measures the velocity of a sheared fluid at specific depths of the sample using the coherence length of the light source. The technique allows the dynamics of 3 pico liter volumes to be probed inside opaque complex fluids. In a study of opaque starch suspensions, classical bulk rheology experiments show non-linear shear thickening, whereas observations of the velocity profiles as a function of distance across the gap show Newtonian behavior. The ability of the technique to measure velocity fluctuations is also discussed for the case of polyacrylamide samples which were observed to display shear banding behavior. A relationship between the viscoelasticity of the sample and the size of the apparent fluctuations is observed.

  8. A metallography and x-ray tomography study of spall damage in ultrapure Al

    SciTech Connect

    Qi, M. L.; Bie, B. X.; Zhao, F. P.; Fan, D.; Luo, S. N.; Hu, C. M.; Ran, X. X.; Xiao, X. H.; Yang, W. G.; Li, P.

    2014-07-15

    We characterize spall damage in shock-recovered ultrapure Al with metallography and x-ray tomography. The measured damage profiles in ultrapure Al induced by planar impact at different shock strengths, can be described with a Gaussian function, and showed dependence on shock strengths. Optical metallography is reasonably accurate for damage profile measurements, and agrees within 10–25% with x-ray tomography. Full tomography analysis showed that void size distributions followed a power law with an exponent of γ = 1.5 ± 2.0, which is likely due to void nucleation and growth, and the exponent is considerably smaller than the predictions from percolation models.

  9. Photoacoustic tomography of vascular compliance in humans

    NASA Astrophysics Data System (ADS)

    Hai, Pengfei; Zhou, Yong; Liang, Jinyang; Li, Chiye; Wang, Lihong V.

    2015-12-01

    Characterization of blood vessel elastic properties can help in detecting thrombosis and preventing life-threatening conditions such as acute myocardial infarction or stroke. Vascular elastic photoacoustic tomography (VE-PAT) is proposed to measure blood vessel compliance in humans. Implemented on a linear-array-based photoacoustic computed tomography system, VE-PAT can quantify blood vessel compliance changes due to simulated thrombosis and occlusion. The feasibility of the VE-PAT system was first demonstrated by measuring the strains under uniaxial loading in perfused blood vessel phantoms and quantifying their compliance changes due to the simulated thrombosis. The VE-PAT system detected a decrease in the compliances of blood vessel phantoms with simulated thrombosis, which was validated by a standard compression test. The VE-PAT system was then applied to assess blood vessel compliance in a human subject. Experimental results showed a decrease in compliance when an occlusion occurred downstream from the measurement point in the blood vessels, demonstrating VE-PAT's potential for clinical thrombosis detection.

  10. High-Confidence Quantum Gate Tomography

    NASA Astrophysics Data System (ADS)

    Johnson, Blake; da Silva, Marcus; Ryan, Colm; Kimmel, Shelby; Donovan, Brian; Ohki, Thomas

    2014-03-01

    Debugging and verification of high-fidelity quantum gates requires the development of new tools and protocols to unwrap the performance of the gate from the rest of the sequence. Randomized benchmarking tomography[2] allows one to extract full information of the unital portion of the gate with high confidence. We report experimental confirmation of the technique's applicability to quantum gate tomography. We show that the method is robust to common experimental imperfections such as imperfect single-shot readout and state preparation. We also demonstrate the ability to characterize non-Clifford gates. To assist in the experimental implementation we introduce two techniques. ``Atomic Cliffords'' use phase ramping and frame tracking to allow single-pulse implementation of the full group of single-qubit Clifford gates. Domain specific pulse sequencers allow rapid implementation of the many thousands of sequences needed. This research was funded by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA), through the Army Research Office contract no. W911NF-10-1-0324.

  11. Atom probe tomography (APT) of carbonate minerals.

    PubMed

    Pérez-Huerta, Alberto; Laiginhas, Fernando; Reinhard, David A; Prosa, Ty J; Martens, Rich L

    2016-01-01

    Atom probe tomography (APT) combines the highest spatial resolution with chemical data at atomic scale for the analysis of materials. For geological specimens, the process of field evaporation and molecular ion formation and interpretation is not yet entirely understood. The objective of this study is to determine the best conditions for the preparation and analysis by APT of carbonate minerals, of great importance in the interpretation of geological processes, focusing on the bulk chemical composition. Results show that the complexity of the mass spectrum is different for calcite and dolomite and relates to dissimilarities in crystalochemical parameters. In addition, APT bulk chemistry of calcite closely matches the expected stoichiometry but fails to provide accurate atomic percentages for elements in dolomite under the experimental conditions evaluated in this work. For both calcite and dolomite, APT underestimates the amount of oxygen based on their chemical formula, whereas it is able to detect small percentages of elemental substitutions in crystal lattices. Overall, our results demonstrate that APT of carbonate minerals is possible, but further optimization of the experimental parameters are required to improve the use of atom probe tomography for the correct interpretation of mineral geochemistry. PMID:26519815

  12. Electrical Capacitance Volume Tomography: Design and Applications

    PubMed Central

    Wang, Fei; Marashdeh, Qussai; Fan, Liang-Shih; Warsito, Warsito

    2010-01-01

    This article reports recent advances and progress in the field of electrical capacitance volume tomography (ECVT). ECVT, developed from the two-dimensional electrical capacitance tomography (ECT), is a promising non-intrusive imaging technology that can provide real-time three-dimensional images of the sensing domain. Images are reconstructed from capacitance measurements acquired by electrodes placed on the outside boundary of the testing vessel. In this article, a review of progress on capacitance sensor design and applications to multi-phase flows is presented. The sensor shape, electrode configuration, and the number of electrodes that comprise three key elements of three-dimensional capacitance sensors are illustrated. The article also highlights applications of ECVT sensors on vessels of various sizes from 1 to 60 inches with complex geometries. Case studies are used to show the capability and validity of ECVT. The studies provide qualitative and quantitative real-time three-dimensional information of the measuring domain under study. Advantages of ECVT render it a favorable tool to be utilized for industrial applications and fundamental multi-phase flow research. PMID:22294905

  13. The Neural Correlates of Driving Performance Identified Using Positron Emission Tomography

    ERIC Educational Resources Information Center

    Horikawa, E.; Okamura, N.; Tashiro, M.; Sakurada, Y.; Maruyama, M.; Arai, H.; Yamaguchi, K.; Sasaki, H.; Yanai, K.; Itoh, M.

    2005-01-01

    Driving is a complex behavior involving multiple cognitive domains. To identify neural correlates of driving performance, [^1^5O]H"2O positron emission tomography was performed using a simulated driving task. Compared with the resting condition, simulated driving increased regional cerebral blood flow (rCBF) in the cerebellum, occipital, and

  14. The Neural Correlates of Driving Performance Identified Using Positron Emission Tomography

    ERIC Educational Resources Information Center

    Horikawa, E.; Okamura, N.; Tashiro, M.; Sakurada, Y.; Maruyama, M.; Arai, H.; Yamaguchi, K.; Sasaki, H.; Yanai, K.; Itoh, M.

    2005-01-01

    Driving is a complex behavior involving multiple cognitive domains. To identify neural correlates of driving performance, [^1^5O]H"2O positron emission tomography was performed using a simulated driving task. Compared with the resting condition, simulated driving increased regional cerebral blood flow (rCBF) in the cerebellum, occipital, and…

  15. Molecular Testing in Multiple Synchronous Lung Adenocarcinomas: Case Report and Literature Review.

    PubMed

    Rafael, Oana C; Lazzaro, Richard; Hasanovic, Adnan

    2016-02-01

    Discovery of driver mutations in pulmonary adenocarcinoma has revolutionized the field of thoracic oncology with major impact on therapy and diagnosis. Testing for EGFR, ALK, and KRAS mutations has become part of everyday practice. We report a case with multiple synchronous primary pulmonary adenocarcinomas in a 72-year-old female with previous history of smoking. The patient presented with cough and bilateral lung ground glass opacities. A positron emission tomography/computed tomography scan showed no activity in mediastinal lymph nodes. She underwent a left upper lobe biopsy and a right upper lobe wedge resection. Pathology revealed 4 morphologically distinct adenocarcinoma foci, suggestive of synchronous primary lung tumors. Molecular testing demonstrated no mutation in the left tumor. Three different driver mutations were present in the right lung tumors: KRAS codon 12 G12D and G12V and EGFR exon 21 L858R mutation, confirming the initial histologic impression. Subsequently, left upper lobe lobectomy showed 3 additional foci of adenocarcinoma with different morphologies, suggestive of synchronous primaries as well. No additional molecular testing was performed. Synchronous pulmonary adenocarcinomas are not uncommon; however, 4 or more synchronous tumors are rare. Distinguishing multiple primary tumors from intrapulmonary metastases is a common problem in thoracic oncology with major implications for staging, prognosis, and treatment. Lung adenocarcinoma subclassification based on predominant and coexisting histologic patterns can greatly facilitate differentiation between intrapulmonary metastases and multiple synchronous tumors. Use of molecular profiling is recommended since it further increases confidence in the diagnostic workup of multiple pulmonary adenocarcinomas and helps guiding therapy. PMID:26350052

  16. Multiple sclerosis

    PubMed Central

    Boster, Aaron L.; Racke, Michael K.

    2013-01-01

    Summary Preliminary studies have suggested that a high salt diet may play a role in the development of autoimmune disease and possibly multiple sclerosis (MS). Promising clinical trial results for 2 new therapies for MS have been reported. Dimethyl fumarate, also known by its investigational name BG-12, became the third oral disease-modifying therapy for MS to be Food and Drug Administration (FDA)approved in March 2013. Interestingly, dimethyl fumarate served as the active compound used for the treatment of psoriasis for decades. Alemtuzumab remains under investigation and is not currently FDA-approved for treatment of MS. Other drugs currently approved for alternative indications are being investigated for use in MS. Additionally, an investigation of alternative dosing strategies for glatiramer acetate suggests that patients may benefit from a higher dose formulation and less frequent medication administration. Advances in basic science research have identified another potential autoantigenic target in MS, KIR4.1, which may provide further insight into MS pathophysiology. PMID:24175156

  17. Fixed-point computation and seismic waveform tomography

    NASA Astrophysics Data System (ADS)

    Boonyasiriwat, Chaiwoot

    This dissertation is comprised of two parts: fixed-point computation and seismic waveform tomography. In the first part, I consider the problem of approximating fixed points of multivariate contractive and nonexpanding functions whose Lipschitz constant is close or equal to 1. Both absolute and residual error criteria are utilized as termination conditions. The circumscribed ellipsoid (CE) algorithm is shown to be able to approximate fixed points in a larger class of functions than possible in previous research. A function in this class is globally expanding but contractive or nonexpanding in the direction of fixed points. Line-search (LS) and circle-search (CS) methods are also developed for solving the fixed-point problem. The computational costs of both methods are lower than those of the CE method when the number of constraints is small. The LS method is well suited for almost linear functions while the CS method is well suited for rotational functions. To combine the strength of both methods, I developed an LS-CS hybrid method that in general is more efficient than either one of these methods. Various multivariate contractive and nonexpanding functions were implemented to test the performance of the proposed methods. The simple iteration (SI) and Newton-Raphson (NR) methods were compared with the CE, LS, CS, and LS-CS hybrid methods. The CE algorithm is an excellent method for low-dimensional functions with discontinuities and/or low regularity. However, the LS method is faster than the CE method in many cases because there is no need to construct an ellipsoid which requires solving an eigenvalue problem. However, the number of constraints for the LS, CS, LS-CS hybrid methods grows with the number of iterations. In the second part, I develop an efficient multiscale method for time-domain waveform tomography. I propose filters that are more efficient than the previously used Hamming-windowed filter. A strategy for choosing optimal frequency bands is proposed to achieve high computational efficiency in the time domain. A staggered-grid, explicit finite-difference method with 4th -order accuracy in space and 2nd-order accuracy in time is used for forward modeling and the adjoint calculation. The adjoint method is utilized in the inversion for an efficient computation of the gradient directions. In the multiscale approach, multifrequency data and multiple grid sizes are used to partially overcome the severe local minima problem of waveform tomography. My method is successfully applied to both 1D and 2D heterogeneous models, and can accurately recover both the low and high wavenumber components of the velocity models. The inversion result for the 2D model also shows that the multiscale method is computationally efficient and converges faster compared to a conventional, single-scale method.

  18. Rare case of isolated splenic metastases from gastric cancer detected with fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Sivanesan, Balasubramanian; Shibu, Deepu; Shinto, Ajit Sugunan

    2013-01-01

    We report a rare case of isolated splenic metastasis from gastric cancer detected with fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT). A 55-year-old man with gastric cancer 1 year post surgery, evaluated with PET/CT showed focal, intense uptake in the spleen, with no other abnormal findings. On splenectomy, the lesion was confirmed as metastasis from gastric cancer pathologically. PMID:24163522

  19. Seismic Tomography in Sensor Networks

    NASA Astrophysics Data System (ADS)

    Shi, L.; Song, W.; Lees, J. M.; Xing, G.

    2012-12-01

    Tomography imaging, applied to seismology, requires a new, decentralized approach if high resolution calculations are to be performed in a sensor network configuration. The real-time data retrieval from a network of large-amount wireless seismic stations to a central server is virtually impossible due to the sheer data amount and resource limitations. In this paper, we propose and design a distributed algorithm for processing data and inverting tomography in the network, while avoiding costly data collections and centralized computations. Based on a partition of the tomographic inversion problem, the new algorithms distribute the computational burden to sensor nodes and perform real-time tomographic inversion in the network, so that we can recover a high resolution tomographic model in real-time under the constraints of network resources. Our emulation results indicate that the distributed algorithms successfully reconstruct the synthetic models, while reducing and balancing the communication and computation cost to a large extent.

  20. Vibration-based photoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Li, Rui; Rajian, Justin R.; Wang, Pu; Slipchenko, Mikhail N.; Cheng, Ji-Xin

    2013-03-01

    Photoacoustic imaging employing molecular overtone vibration as contrast mechanism opens a new avenue for deep tissue imaging with chemical bond selectivity. Here, we demonstrate vibration-based photoacoustic tomography with an imaging depth on the centimeter scale. To provide sufficient pulse energy at the overtone transition wavelengths, we constructed a compact, barium nitrite crystal-based Raman laser for excitation of 2nd overtone of C-H bond. Using a 5-ns Nd:YAG laser as pumping source, up to 105 mJ pulse energy at 1197 nm was generated. Vibrational photoacoutic spectroscopy and tomography of phantom (polyethylene tube) immersed in whole milk was performed. With a pulse energy of 47 mJ on the milk surface, up to 2.5 cm penetration depth was reached with a signal-to-noise ratio of 12.

  1. Characterization of pore structure and strain localization in Majella limestone by X-ray computed tomography and digital image correlation

    NASA Astrophysics Data System (ADS)

    Ji, Yuntao; Hall, Stephen A.; Baud, Patrick; Wong, Teng-fong

    2015-02-01

    Standard techniques for computed tomography imaging are not directly applicable to a carbonate rock because of the geometric complexity of its pore space. In this study, we first characterized the pore structure in Majella limestone with 30 per cent porosity. Microtomography data acquired on this rock was partitioned into three distinct domains: macropores, solid grains, and an intermediate domain made up of voxels of solid embedded with micropores below the resolution. A morphological analysis of the microtomography images shows that in Majella limestone both the solid and intermediate domains are interconnected in a manner similar to that reported previously in a less porous limestone. We however show that the macroporosity in Majella limestone is fundamentally different, in that it has a percolative backbone which may contribute significantly to its permeability. We then applied for the first time 3-D-volumetric digital image correlation (DIC) to characterize the mode of mechanical failure in this limestone. Samples were triaxially deformed over a wide range of confining pressures. Tomography imaging was performed on these samples before and after deformation. Inelastic compaction was observed at all tested pressures associated with both brittle and ductile behaviors. Our DIC analysis reveals the structure of compacting shear bands in Majella limestone deformed in the transitional regime. It also indicates an increase of geometric complexity with increasing confinement-from a planar shear band, to a curvilinear band, and ultimately to a diffuse multiplicity of bands, before shear localization is inhibited as the failure mode completes the transition to delocalized cataclastic flow.

  2. Performance of MCAO on the E-ELT using the Fractal Iterative Method for fast atmospheric tomography

    NASA Astrophysics Data System (ADS)

    Tallon, Michel; Béchet, Clémentine; Tallon-Bosc, Isabelle; Le Louarn, Miska; Thiébaut, Éric; Clare, Richard; Marchetti, Enrico

    2011-09-01

    Adaptive optics (AO) on Extremely Large Telescopes (ELTs) must overcome the difficulty of solving a huge number of equations in real time, especially when atmospheric tomography is involved. This is particularly the case for multi-conjugate or multi-objects AO systems. The Fractal Iterative Method (FrIM) has been introduced as a fast iterative algorithm for minimum variance wavefront reconstruction and control on ELTs. In particular, it includes an accurate fast computation of turbulence priors by using the so-called fractal operator. We present the first results obtained with FrIM in closed-loop in the context of atmospheric tomography. The method has been tested on Octopus, the end-to-end AO simulator at ESO, by considering MAORY, the multi-conjugate AO module planed for the E-ELT. This module aims at correcting a 2 arcmin field-of-view, by using 3 deformable mirrors, 6 Sodium laser guide stars, and 3 natural guide stars for low-order wavefront sensing. We show the performance obtained in different conditions and analyze the effect of some parameters of FrIM, like the weight of the priors, or the number of conjugate gradient iterations for solving the reconstruction. We show how the duration of the simulations can be shortened on such a large aperture, with the introduction of artificial vibrations in the simulation. The results are also compared to a more classical approach using matrix-vector multiplication.

  3. Cumulative phase delay imaging for contrast-enhanced ultrasound tomography

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    Standard dynamic-contrast enhanced ultrasound (DCE-US) imaging detects and estimates ultrasound-contrast-agent (UCA) concentration based on the amplitude of the nonlinear (harmonic) components generated during ultrasound (US) propagation through UCAs. However, harmonic components generation is not specific to UCAs, as it also occurs for US propagating through tissue. Moreover, nonlinear artifacts affect standard DCE-US imaging, causing contrast to tissue ratio reduction, and resulting in possible misclassification of tissue and misinterpretation of UCA concentration. Furthermore, no contrast-specific modality exists for DCE-US tomography; in particular speed-of-sound changes due to UCAs are well within those caused by different tissue types. Recently, a new marker for UCAs has been introduced. A cumulative phase delay (CPD) between the second harmonic and fundamental component is in fact observable for US propagating through UCAs, and is absent in tissue. In this paper, tomographic US images based on CPD are for the first time presented and compared to speed-of-sound US tomography. Results show the applicability of this marker for contrast specific US imaging, with cumulative phase delay imaging (CPDI) showing superior capabilities in detecting and localizing UCA, as compared to speed-of-sound US tomography. Cavities (filled with UCA) which were down to 1 mm in diameter were clearly detectable. Moreover, CPDI is free of the above mentioned nonlinear artifacts. These results open important possibilities to DCE-US tomography, with potential applications to breast imaging for cancer localization.

  4. High resolution imaging with impulse based thermoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Kellnberger, Stephan; Hajiaboli, Amir; Sergiadis, George; Razansky, Daniel; Ntziachristos, Vasilis

    2011-07-01

    Existing imaging modalities like microwave- or radiofrequency (RF) induced thermoacoustic tomography systems show the potential for resolving structures deep inside tissue due to the high penetration properties of RF. However, one of the major drawbacks of existing thermoacoustic tomography systems with pulse modulated carrier frequency excitation is the compromise between efficient signal generation and attainable spatial resolution. In order to overcome limitations of conventional thermoacoustic imaging methods, we herein present and experimentally validate our novel approach towards high resolution thermoacoustic tomography. Instead of carrier-frequency amplification, we utilize ultrahigh-energy electromagnetic impulses at nanosecond duration with near-field energy coupling, thus maintaining thermoacoustic signal strength without compromising spatial resolution. Preliminary experiments on highly absorbing objects, consisting of copper wires with characteristic sizes of ~100 μm, reveal the resolution performance which yields 160 μm. Furthermore, benefits like its cost effectiveness, simplicity and compactness with the potential application in small animal imaging as well as human body imaging show that thermoacoustic tomography with impulse excitation is a promising imaging modality which has a broad range of applications.

  5. 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.

  6. 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.

  7. Statistical analysis of high density diffuse optical tomography

    PubMed Central

    Hassanpour, Mahlega S.; White, Brian R.; Eggebrecht, Adam T.; Ferradal, Silvina L.; Snyder, Abraham Z.; Culver, Joseph P.

    2014-01-01

    High density diffuse optical tomography (HD-DOT) is a noninvasive neuroimaging modality with moderate spatial resolution and localization accuracy. Due to portability and wear-ability advantages, HD-DOT has the potential to be used in populations that are not amenable to functional magnetic resonance imaging (fMRI), such as hospitalized patients and young children. However, whereas the use of event-related stimuli designs, general linear model (GLM) analysis, and imaging statistics are standardized and routine with fMRI, such tools are not yet common practice in HD-DOT. In this paper we adapt and optimize fundamental elements of fMRI analysis for application to HD-DOT. We show the use of event-related protocols and GLM de-convolution analysis in un-mixing multi-stimuli event-related HD-DOT data. Statistical parametric mapping (SPM) in the framework of a general linear model is developed considering the temporal and spatial characteristics of HD- DOT data. The statistical analysis utilizes a random field noise model that incorporates estimates of the local temporal and spatial correlations of the GLM residuals. The multiple-comparison problem is addressed using a cluster analysis based on non-stationary Gaussian random field theory. These analysis tools provide access to a wide range of experimental designs necessary for the study of the complex brain functions. In addition, they provide a foundation for understanding and interpreting HD-DOT results with quantitative estimates for the statistical significance of detected activation foci. PMID:23732886

  8. Cyst-based measurements for assessing lymphangioleiomyomatosis in computed tomography

    SciTech Connect

    Lo, P. Brown, M. S.; Kim, H.; Kim, H.; Goldin, J. G.; Argula, R.; Strange, C.

    2015-05-15

    Purpose: To investigate the efficacy of a new family of measurements made on individual pulmonary cysts extracted from computed tomography (CT) for assessing the severity of lymphangioleiomyomatosis (LAM). Methods: CT images were analyzed using thresholding to identify a cystic region of interest from chest CT of LAM patients. Individual cysts were then extracted from the cystic region by the watershed algorithm, which separates individual cysts based on subtle edges within the cystic regions. A family of measurements were then computed, which quantify the amount, distribution, and boundary appearance of the cysts. Sequential floating feature selection was used to select a small subset of features for quantification of the severity of LAM. Adjusted R{sup 2} from multiple linear regression and R{sup 2} from linear regression against measurements from spirometry were used to compare the performance of our proposed measurements with currently used density based CT measurements in the literature, namely, the relative area measure and the D measure. Results: Volumetric CT data, performed at total lung capacity and residual volume, from a total of 49 subjects enrolled in the MILES trial were used in our study. Our proposed measures had adjusted R{sup 2} ranging from 0.42 to 0.59 when regressing against the spirometry measures, with p < 0.05. For previously used density based CT measurements in the literature, the best R{sup 2} was 0.46 (for only one instance), with the majority being lower than 0.3 or p > 0.05. Conclusions: The proposed family of CT-based cyst measurements have better correlation with spirometric measures than previously used density based CT measurements. They show potential as a sensitive tool for quantitatively assessing the severity of LAM.

  9. One step geometrical calibration method for optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Díaz Díaz, Jesús; Stritzel, Jenny; Rahlves, Maik; Majdani, Omid; Reithmeier, Eduard; Ortmaier, Tobias; Roth, Bernhard

    2016-01-01

    We present a novel one-step calibration methodology for geometrical distortion correction for optical coherence tomography (OCT). A calibration standard especially designed for OCT is introduced, which consists of an array of inverse pyramidal structures. The use of multiple landmarks situated on four different height levels on the pyramids allow performing a 3D geometrical calibration. The calibration procedure itself is based on a parametric model of the OCT beam propagation. It is validated by experimental results and enables the reduction of systematic errors by more than one order of magnitude. In future, our results can improve OCT image reconstruction and interpretation for medical applications such as real time monitoring of surgery.

  10. Correlated cryogenic photoactivated localization microscopy and cryo-electron tomography.

    PubMed

    Chang, Yi-Wei; Chen, Songye; Tocheva, Elitza I; Treuner-Lange, Anke; Lbach, Stephanie; Sgaard-Andersen, Lotte; Jensen, Grant J

    2014-07-01

    Cryo-electron tomography (CET) produces three-dimensional images of cells in a near-native state at macromolecular resolution, but identifying structures of interest can be challenging. Here we describe a correlated cryo-PALM (photoactivated localization microscopy)-CET method for localizing objects within cryo-tomograms to beyond the diffraction limit of the light microscope. Using cryo-PALM-CET, we identified multiple and new conformations of the dynamic type VI secretion system in the crowded interior of Myxococcus xanthus. PMID:24813625

  11. Computed tomography imaging of coronary artery plaque: characterization and prognosis.

    PubMed

    Baumann, Stefan; Renker, Matthias; Meinel, Felix G; Wichmann, Julian L; Fuller, Stephen R; Bayer, Richard R; Schoepf, U Joseph; Steinberg, Daniel H

    2015-03-01

    The exact definition and prognostication of vulnerable plaque remain elusive, and multiple imaging modalities aim to identify these plaques. As a noninvasive technique for the diagnosis of coronary artery disease, coronary computed tomography angiography has become increasingly utilized, primarily in patients with an elevated cardiovascular risk profile. Recent advances in technical methods have allowed for improved visualization of the vessel wall and surrounding tissue, allowing for improved characterization of vulnerable plaques by identifying features such as low-density plaques, positive remodeling, and spotty calcification. Quantification and qualification of these plaques may enhance the ability to predict future cardiovascular events. PMID:25726996

  12. Inherent Limitations of Hydraulic Tomography

    USGS Publications Warehouse

    Bohling, G.C.; Butler, J.J.

    2010-01-01

    We offer a cautionary note in response to an increasing level of enthusiasm regarding high-resolution aquifer characterization with hydraulic tomography. We use synthetic examples based on two recent field experiments to demonstrate that a high degree of nonuniqueness remains in estimates of hydraulic parameter fields even when those estimates are based on simultaneous analysis of a number of carefully controlled hydraulic tests. We must, therefore, be careful not to oversell the technique to the community of practicing hydrogeologists, promising a degree of accuracy and resolution that, in many settings, will remain unattainable, regardless of the amount of effort invested in the field investigation. No practically feasible amount of hydraulic tomography data will ever remove the need to regularize or bias the inverse problem in some fashion in order to obtain a unique solution. Thus, along with improving the resolution of hydraulic tomography techniques, we must also strive to couple those techniques with procedures for experimental design and uncertainty assessment and with other more cost-effective field methods, such as geophysical surveying and, in unconsolidated formations, direct-push profiling, in order to develop methods for subsurface characterization with the resolution and accuracy needed for practical field applications. Copyright ?? 2010 The Author(s). Journal compilation ?? 2010 National Ground Water Association.

  13. Review of Terahertz Tomography Techniques

    NASA Astrophysics Data System (ADS)

    Guillet, J. P.; Recur, B.; Frederique, L.; Bousquet, B.; Canioni, L.; Manek-Hnninger, I.; Desbarats, P.; Mounaix, P.

    2014-04-01

    Terahertz and millimeter waves penetrate various dielectric materials, including plastics, ceramics, crystals, and concrete, allowing terahertz transmission and reflection images to be considered as a new imaging tool complementary to X-Ray or Infrared. Terahertz imaging is a well-established technique in various laboratory and industrial applications. However, these images are often two-dimensional. Three-dimensional, transmission-mode imaging is limited to thin samples, due to the absorption of the sample accumulated in the propagation direction. A tomographic imaging procedure can be used to acquire and to render three-dimensional images in the terahertz frequency range, as in the optical, infrared or X-ray regions of the electromagnetic spectrum. In this paper, after a brief introduction to two dimensional millimeter waves and terahertz imaging we establish the principles of tomography for Terahertz Computed tomography (CT), tomosynthesis (TS), synthetic aperture radar (SAR) and time-of-flight (TOF) terahertz tomography. For each technique, we present advantages, drawbacks and limitations for imaging the internal structure of an object.

  14. Multiple Masculinity

    ERIC Educational Resources Information Center

    Il'inykh, S. A.

    2012-01-01

    Data from a sociological study conducted in Novosibirsk show that in this Russian population the "real man" is expected to pursue victory, risk, struggle, leadership, and success. In addition, however, there is also a natural masculinity in which there is no rigid framework of the image of the "real man." Moreover, natural masculinity represents

  15. Multiple Masculinity

    ERIC Educational Resources Information Center

    Il'inykh, S. A.

    2012-01-01

    Data from a sociological study conducted in Novosibirsk show that in this Russian population the "real man" is expected to pursue victory, risk, struggle, leadership, and success. In addition, however, there is also a natural masculinity in which there is no rigid framework of the image of the "real man." Moreover, natural masculinity represents…

  16. Behind the curtain of tauopathy: a show of multiple players orchestrating tau toxicity.

    PubMed

    Huang, Yunpeng; Wu, Zhihao; Zhou, Bing

    2016-01-01

    tau, a microtubule-associated protein, directly binds with microtubules to dynamically regulate the organization of cellular cytoskeletons, and is especially abundant in neurons of the central nervous system. Under disease conditions such as Pick's disease, progressive supranuclear palsy, frontotemporal dementia, parkinsonism linked to chromosome 17 and Alzheimer's disease, tau proteins can self-assemble to paired helical filaments progressing to neurofibrillary tangles. In these diseases, collectively referred to as "tauopathies", alterations of diverse tau modifications including phosphorylation, metal ion binding, glycosylation, as well as structural changes of tau proteins have all been observed, indicating the complexity and variability of factors in the regulation of tau toxicity. Here, we review our current knowledge and hypotheses from relevant studies on tau toxicity, emphasizing the roles of phosphorylations, metal ions, folding and clearance control underlining tau etiology and their regulations. A summary of clinical efforts and associated findings of drug candidates under development is also presented. It is hoped that a more comprehensive understanding of tau regulation will provide us with a better blueprint of tau networking in neuronal cells and offer hints for the design of more efficient strategies to tackle tau-related diseases in the future. PMID:26403791

  17. Bacterial quorum sensing inhibitors: attractive alternatives for control of infectious pathogens showing multiple drug resistance.

    PubMed

    Bhardwaj, Ashima K; Vinothkumar, Kittappa; Rajpara, Neha

    2013-04-01

    Quorum sensing (QS) is a bacterial communication process that depends on the bacterial population density. It involves small diffusible signaling molecules which activate the expression of myriad genes that control diverse array of functions like bioluminescence, virulence, biofilm formation, sporulation, to name a few. Since QS is responsible for virulence in the clinically relevant bacteria, inhibition of QS appears to be a promising strategy to control these pathogenic bacteria. With indiscriminate use of antibiotics, there has been an alarming increase in the number of antibiotic resistant pathogens. Antibiotics are no longer the magic bullets they were once thought to be and therefore there is a need for development of new antibiotics and/or other novel strategies to combat the infections caused by multidrug resistant organisms. Quorum sensing inhibition or quorum quenching has been pursued as one of such novel strategies. While antibiotics kill or slow down the growth of bacteria, quorum sensing inhibitors (QSIs) or quorum quenchers (QQs) attenuate bacterial virulence. A large body of work on QS has been carried out in deadly pathogens like Pseudomonas aeruginosa, Staphylococcus aureus, Vibrio fischeri, V. harveyi, Escherichia coli and V. cholerae etc to unravel the mechanisms of QS as well as identify and study QSIs. This review describes various aspects of QS, QSI, different model systems to study these phenomena and recent patents on various QSIs. It suggests QSIs as attractive alternatives for controlling human, animal and plant pathogens and their utility in agriculture and other industries. PMID:23394143

  18. X-ray scatter tomography for explosives detection

    NASA Astrophysics Data System (ADS)

    Harding, G.

    2004-10-01

    An account is given of three explosive detection techniques based on X-ray scatter tomography i.e. coherent scatter computed tomography, energy-dispersive X-ray diffraction tomography and Compton back-scatter imaging. Following an introduction to the physics of the underlying X-ray interaction phenomena, the principles on which these image-forming techniques are based are elaborated. A brief description is given of some of the parameters relevant to the X-ray scatter system design and of the optimisation of these parameters for the target application. Signal degradation owing to self-attenuation of the primary and scatter radiations and multiple scattering is discussed and procedures to correct for these effects are presented. The above techniques have been applied to the problem of identifying and detecting explosive material in airport baggage and buried land mines. Decision criteria needed to limit the number of "false alarms" are discussed. Representative results drawn from the fields of baggage inspection and mine clearance are given.

  19. EPiK-a Workflow for Electron Tomography in Kepler*

    PubMed Central

    Wang, Jianwu; Crawl, Daniel; Phan, Sébastien; Lawrence, Albert; Ellisman, Mark

    2015-01-01

    Scientific workflows integrate data and computing interfaces as configurable, semi-automatic graphs to solve a scientific problem. Kepler is such a software system for designing, executing, reusing, evolving, archiving and sharing scientific workflows. Electron tomography (ET) enables high-resolution views of complex cellular structures, such as cytoskeletons, organelles, viruses and chromosomes. Imaging investigations produce large datasets. For instance, in Electron Tomography, the size of a 16 fold image tilt series is about 65 Gigabytes with each projection image including 4096 by 4096 pixels. When we use serial sections or montage technique for large field ET, the dataset will be even larger. For higher resolution images with multiple tilt series, the data size may be in terabyte range. Demands of mass data processing and complex algorithms require the integration of diverse codes into flexible software structures. This paper describes a workflow for Electron Tomography Programs in Kepler (EPiK). This EPiK workflow embeds the tracking process of IMOD, and realizes the main algorithms including filtered backprojection (FBP) from TxBR and iterative reconstruction methods. We have tested the three dimensional (3D) reconstruction process using EPiK on ET data. EPiK can be a potential toolkit for biology researchers with the advantage of logical viewing, easy handling, convenient sharing and future extensibility. PMID:25621086

  20. Adjoint tomography of Europe

    NASA Astrophysics Data System (ADS)

    Zhu, H.; Bozdag, E.; Peter, D. B.; Tromp, J.

    2011-12-01

    We use spectral-element and adjoint methods to iteratively resolve crustal and upper mantle heterogeneity in Europe, using 159 earthquakes, with magnitudes from 5 to 6.5, and data from 338 stations. Crustal model EPcrust1.0 (Molinari& Morelli, 2010) combined with mantle model S362ANI (Kustowski et al. 2008) comprise the initial 3D model M00. Before the iterative inversion, earthquake source parameters (i.e, centroid moment tensor and location), are recalculated using 3D Green's functions and Fréchet derivatives. Since we concentrate on upper mantle structures, involving significant anisotropy in the asthenosphere, transversely isotropic (frequency-dependent) traveltime sensitivity kernels are employed in the inversion. Long-period surface waves (25 s -- 150 s) and short-period body waves (15 s -- 40 s) are combined to constrain shallow and deep structures simultaneously. With each iteration, higher frequency signals are incorporated in the inversion. Statistical assessments of traveltime anomalies and logarithmic waveform differences enable us to validate the inverted sources and structural parameters. Our current model, M15, shows numerous interesting features, for instance, slabs underneath the Hellenic, Vrancea and Calabria arcs, a slab detachment underneath the Central Apennines, mantle upwelling associated with the Eifel hotspot in Northern German, slow wavespeed structures in several back-arc basins, e.g., the Ponnonian basin and the Tyrrhenian sea, and a sharp transition of the Teisseyre-Tornquist suture zone between central Europe and the East European platform.

  1. Single particle tomography in EMAN2.

    PubMed

    Galaz-Montoya, Jesús G; Flanagan, John; Schmid, Michael F; Ludtke, Steven J

    2015-06-01

    Single particle tomography (SPT or subtomogram averaging) offers a powerful alternative to traditional 2-D single particle reconstruction for studying conformationally or compositionally heterogeneous macromolecules. It can also provide direct observation (without labeling or staining) of complexes inside cells at nanometer resolution. The development of computational methods and tools for SPT remains an area of active research. Here we present the EMAN2.1 SPT toolbox, which offers a full SPT processing pipeline, from particle picking to post-alignment analysis of subtomogram averages, automating most steps. Different algorithm combinations can be applied at each step, providing versatility and allowing for procedural cross-testing and specimen-specific strategies. Alignment methods include all-vs-all, binary tree, iterative single-model refinement, multiple-model refinement, and self-symmetry alignment. An efficient angular search, Graphic Processing Unit (GPU) acceleration and both threaded and distributed parallelism are provided to speed up processing. Finally, automated simulations, per particle reconstruction of subtiltseries, and per-particle Contrast Transfer Function (CTF) correction have been implemented. Processing examples using both real and simulated data are shown for several structures. PMID:25956334

  2. Postprocessing in Maxillofacial Multidetector Computed Tomography.

    PubMed

    Mazziotti, Silvio; Blandino, Alfredo; Gaeta, Michele; Bottari, Antonio; Sofia, Carmelo; D'Angelo, Tommaso; Ascenti, Giorgio

    2015-08-01

    Multidetector computed tomography (CT) and volumetric rendering techniques have always been a useful support for the anatomical and pathological study of the maxillofacial district. Nowadays accessibility to multidetector CT scanners allows the achievement of images with an extremely thin collimation and with high spatial resolution, not only along the axial plane but also along the patient's longitudinal axis. This feature is the main theoretical assumption for multiplanar imaging and for an optimal 3-dimensional postprocessing. Multiplanar reconstruction (MPR) techniques permit images along any plane in the space to be obtained, including curved planes; this feature allows the representation in a single bidimensional image of different anatomical structures that develop on multiple planes. For this reason MPR techniques represent an unavoidable step for the study of traumatic pathology as well as of malformative, neoplastic, and inflammatory pathologies. Among 3-dimensional techniques, Maximum Intensity Projection and Shaded Surface Display are routinely used in clinical practice. In addition, volumetric rendering techniques allow a better efficacy in representing the different tissues of maxillofacial district. Each of these techniques give the radiologist an undoubted support for the diagnosis and the characterization of traumatic and malformative conditions, have a critical utility in the neoplastic evaluation of primary or secondary bone involvement, and are also used in the planning of the most modern radiosurgical treatments. The aim of this article is to define the main technical aspects of imaging postprocessing in maxillofacial CT and to summarize when each technique is indicated, according to the different pathologies of this complex anatomical district. PMID:26002181

  3. Motion clustering for deblurring multispectral optoacoustic tomography images of the mouse heart

    NASA Astrophysics Data System (ADS)

    Taruttis, Adrian; Claussen, Jing; Razansky, Daniel; Ntziachristos, Vasilis

    2012-01-01

    Cardiac imaging in small animals is a valuable tool in basic biological research and drug discovery for cardiovascular disease. Multispectral optoacoustic tomography (MSOT) represents an emerging imaging modality capable of visualizing specific tissue chromophores at high resolution and deep in tissues in vivo by separating their spectral signatures. Whereas single-wavelength images can be acquired by multielement ultrasound detection in real-time imaging, using multiple wavelengths at separate times can lead to image blurring due to motion during acquisition. Therefore, MSOT imaging of the heart results in degraded resolution because of the heartbeat. In this work, we applied a clustering algorithm, k-means, to automatically separate a sequence of single-pulse images at multiple excitation wavelengths into clusters corresponding to different stages of the cardiac cycle. We then performed spectral unmixing on each cluster to obtain images of tissue intrinsic chromophores at different cardiac stages, showing reduced sensitivity to motion compared to signal averaging without clustering. We found that myocardium images of improved resolution and contrast can be achieved using MSOT motion clustering correction. The correction method presented could be generally applied to other MSOT imaging applications prone to motion artifacts, for example, by respiration and heartbeat.

  4. Imaging modal content of cone photoreceptors using adaptive optics optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Liu, Zhuolin; Kocaoglu, Omer P.; Turner, Timothy L.; Miller, Donald T.

    2015-03-01

    It has been long established that photoreceptors capture light based on the principles of optical waveguiding. Yet after decades of experimental and theoretical investigations considerable uncertainty remains, even for the most basic prediction as to whether photoreceptors support more than a single waveguide mode. To test for modal behavior in human cone photoreceptors, we took advantage of adaptive-optics optical coherence tomography (AO-OCT, ?c=785 nm) to noninvasively image in three dimensions the reflectance profiles generated in the inner and outer segments (IS, OS) of cones. Mode content was examined over a range of cone diameters by imaging cones from 0.6 to 10 retinal eccentricity (n = 1802). Fundamental to the method was extraction of reflections at the cone IS/OS junction and cone outer segment tip (COST). Modal content properties of size, circularity and orientation were quantified using second moment analysis. Analysis of the cone reflections indicates waveguide properties of cone IS and OS depend on segment diameter. Cone IS was found to support a single mode near the fovea (<=3) and multiple modes further away (<4). In contrast, no evidence of multiple modes was found in the cone OSs. The IS/OS and COST reflections share a common optical aperture, are most circular near the fovea, and show no orientation preference.

  5. Reconstruction of apparent orthotropic conductivity tensor image using magnetic resonance electrical impedance tomography

    SciTech Connect

    Sajib, Saurav Z. K.; Kim, Ji Eun; Jeong, Woo Chul; Kim, Hyung Joong; Woo, Eung Je; Kwon, Oh In

    2015-03-14

    Magnetic resonance electrical impedance tomography visualizes current density and/or conductivity distributions inside an electrically conductive object. Injecting currents into the imaging object along at least two different directions, induced magnetic flux density data can be measured using a magnetic resonance imaging scanner. Without rotating the object inside the scanner, we can measure only one component of the magnetic flux density denoted as B{sub z}. Since the biological tissues such as skeletal muscle and brain white matter show strong anisotropic properties, the reconstruction of anisotropic conductivity tensor is indispensable for the accurate observations in the biological systems. In this paper, we propose a direct method to reconstruct an axial apparent orthotropic conductivity tensor by using multiple B{sub z} data subject to multiple injection currents. To investigate the anisotropic conductivity properties, we first recover the internal current density from the measured B{sub z} data. From the recovered internal current density and the curl-free condition of the electric field, we derive an over-determined matrix system for determining the internal absolute orthotropic conductivity tensor. The over-determined matrix system is designed to use a combination of two loops around each pixel. Numerical simulations and phantom experimental results demonstrate that the proposed algorithm stably determines the orthotropic conductivity tensor.

  6. Reconstruction of apparent orthotropic conductivity tensor image using magnetic resonance electrical impedance tomography

    NASA Astrophysics Data System (ADS)

    Sajib, Saurav Z. K.; Kim, Ji Eun; Jeong, Woo Chul; Kim, Hyung Joong; Kwon, Oh In; Woo, Eung Je

    2015-03-01

    Magnetic resonance electrical impedance tomography visualizes current density and/or conductivity distributions inside an electrically conductive object. Injecting currents into the imaging object along at least two different directions, induced magnetic flux density data can be measured using a magnetic resonance imaging scanner. Without rotating the object inside the scanner, we can measure only one component of the magnetic flux density denoted as Bz. Since the biological tissues such as skeletal muscle and brain white matter show strong anisotropic properties, the reconstruction of anisotropic conductivity tensor is indispensable for the accurate observations in the biological systems. In this paper, we propose a direct method to reconstruct an axial apparent orthotropic conductivity tensor by using multiple Bz data subject to multiple injection currents. To investigate the anisotropic conductivity properties, we first recover the internal current density from the measured Bz data. From the recovered internal current density and the curl-free condition of the electric field, we derive an over-determined matrix system for determining the internal absolute orthotropic conductivity tensor. The over-determined matrix system is designed to use a combination of two loops around each pixel. Numerical simulations and phantom experimental results demonstrate that the proposed algorithm stably determines the orthotropic conductivity tensor.

  7. Noninvasive blood-free full quantification of positron emission tomography radioligand binding

    PubMed Central

    Zanderigo, Francesca; Ogden, R Todd; Parsey, Ramin V

    2015-01-01

    Full quantification of a positron emission tomography (PET) radioligand binding to its target is preferred because it requires the fewest assumptions, but generally involves measuring the concentration of free radioligand in the arterial plasma by collecting blood samples from the subject's radial artery during the scan, and performing metabolite analysis. This invasive, costly procedure deters subjects' participation, and requires specialized staff and equipment. Simultaneous estimation (SIME) can fully quantify binding using only PET data from multiple brain regions and one individual anchor value, which is based on a single arterial blood sample. Drawing this sample can still be challenging in clinical settings, particularly when using simultaneous PET/magnetic resonance scanners. Here we propose a methodology for full quantification of binding that does not require any blood samples. The methodology substitutes the SIME blood-based anchor with a value predicted using multiple linear regression of noninvasive, easy-to-collect variables related to the radioligand blood concentration, and individual metabolism, such as injected dose, body mass index, or body surface area. As a study case, we show here the methodology in comparison to analysis with full arterial-line blood sampling in a cohort of 23 available scans with [11C]CUMI-101, a partial agonist of the serotonin 5-HT1A receptors. PMID:25370860

  8. Optical coherence tomography examination of hair

    NASA Astrophysics Data System (ADS)

    Gong, Wei; Huang, Zheng; Xu, Jianshu; Yang, Hongqin; Li, Hui; Xie, Shusen

    2014-09-01

    Human hair is a keratinous tissue composed mostly of flexible keratin, which can form a complex architecture consisting of distinct compartments or units (e.g. hair bulb, inner root sheath, shaft). Variations in hair shaft morphology can reflect ethnical diversity, but may also indicate internal diseases, nutritional deficiency, or hair and scalp disorders. Hair shaft abnormalities in cross section and diameter, as well as ultramorphological characterization and follicle shapes, might be visualized non-invasively by high-speed 2D and 3D optical coherence tomography (OCT). In this study, swept source OCT (ThorLabs) was used to examine human hair. Preliminary results showed that the high-speed OCT was a suitable and promising tool for non-invasive analysis of hair conditions.

  9. In vivo multiphoton tomography of skin cancer

    NASA Astrophysics Data System (ADS)

    Knig, Karsten; Riemann, Iris; Ehlers, Alexander; Buckle, Rainer; Dimitrow, Enrico; Kaatz, Martin; Fluhr, Joachim; Elsner, Peter

    2006-02-01

    The multiphoton tomograph DermaInspect was used to perform first clinical studies on the early non-invasive detection of skin cancer based on non-invasive optical sectioning of skin by two-photon autofluorescence and second harmonic generation. In particular, deep-tissue pigmented lesions -nevi- have been imaged with intracellular resolution using near infrared (NIR) femtosecond laser radiation. So far, more than 250 patients have been investigated. Cancerous tissues showed significant morphological differences compared to normal skin layers. In the case of malignant melanoma, the occurrence of luminescent melanocytes has been detected. Multiphoton tomography will become a novel non-invasive method to obtain high-resolution 3D optical biopsies for early cancer detection, treatment control, and in situ drug screening.

  10. [The ureters: findings at multidetector computed tomography].

    PubMed

    Lpez Amaya, J E; Meja Restrepo, J; Nicolau Molina, C; Zuluaga Santamara, A; Mazzaro, M

    2010-01-01

    Multidetector computed tomography (MDCT) and advances in CT urography techniques have enabled vast improvements in the depiction of the ureter. Studies of the ureter can find a wide variety of conditions including congenital defects and anatomic variants (anomalies in the origin, distribution, and distal insertion of the ureter) as well as all benign and malignant causes of focal and diffuse wall thickening (inflammatory and infectious processes, and neoplasms, as well as iatrogenic thickening and postsurgical changes). Other benign processes like ureteral kinking and stenosis due to extrinsic compression of the iliac vessels are also well characterized by MDCT. The aim of this article is to show the spectrum of ureteral variants and disease apart from common entities related to stones. PMID:20627329

  11. Mouse brain imaging using photoacoustic computed tomography

    NASA Astrophysics Data System (ADS)

    Lou, Yang; Xia, Jun; Wang, Lihong V.

    2014-03-01

    Photoacoustic computed tomography (PACT) provides structural and functional information when used in small animal brain imaging. Acoustic distortion caused by bone structures largely limits the deep brain image quality. In our work, we present ex vivo PACT images of freshly excised mouse brain, intending that can serve as a gold standard for future PACT in vivo studies on small animal brain imaging. Our results show that structures such as the striatum, hippocampus, ventricles, and cerebellum can be clearly di erentiated. An artery feature called the Circle of Willis, located at the bottom of the brain, can also be seen. These results indicate that if acoustic distortion can be accurately accounted for, PACT should be able to image the entire mouse brain with rich structural information.

  12. Compressed sensing for ultrasound computed tomography.

    PubMed

    van Sloun, Ruud; Pandharipande, Ashish; Mischi, Massimo; Demi, Libertario

    2015-06-01

    Ultrasound computed tomography (UCT) allows the reconstruction of quantitative tissue characteristics, such as speed of sound, mass density, and attenuation. Lowering its acquisition time would be beneficial; however, this is fundamentally limited by the physical time of flight and the number of transmission events. In this letter, we propose a compressed sensing solution for UCT. The adopted measurement scheme is based on compressed acquisitions, with concurrent randomised transmissions in a circular array configuration. Reconstruction of the image is then obtained by combining the born iterative method and total variation minimization, thereby exploiting variation sparsity in the image domain. Evaluation using simulated UCT scattering measurements shows that the proposed transmission scheme performs better than uniform undersampling, and is able to reduce acquisition time by almost one order of magnitude, while maintaining high spatial resolution. PMID:25872207

  13. Plasma diagnostic x-ray tomography system

    SciTech Connect

    Eshelman, C.D.; Tseng, H.K.; Dolan, T.J. ); Prelas, M.A. )

    1991-03-01

    A radiation-hardened 60-channel x-ray tomography system has been developed to determine the two-dimensional distribution of x-ray emissivity from magnetically confined plasmas. In order to maximize their field of view, the diode arrays are mounted in re-entrant tubes inside the plasma chamber diagnostic ports. Metal foil vacuum windows serve as x-ray filters and permit the diodes and cables to be at atmospheric pressure. Preamplifiers are mounted at the outside end of the re-entrant tubes. The diode arrays and preamplifiers are protected from the harsh radiation environment by lead shielding. Image reconstruction is done using the harmonic expansion method or the linear algebraic method. For plasmas with some cylindrical symmetry the harmonic expansion method is superior, but for small discrete objects the Cartesian algebraic method is better. Preliminary data from the Missouri Magnetic Mirror plasma with electron cyclotron resonance heating show evidence of a hot electron ring.

  14. Electrical resistance tomography of concrete structures

    SciTech Connect

    Daily, W.; Ramirez, A.; Binley, A.; Henry-Poulter, S.

    1993-10-01

    The purpose of this work is to determine the feasibility of using Electrical resistance tomography (ERT) to nondestructively examine the interior of concrete structures such as bridge pillars and roadways. We report the results of experiments wherein ERT is used to image the two concrete specimens in the laboratory. Each specimen is 5 inches square and 12 inches long and contained steel reinforcing rods along its length. Twenty electrodes were placed on each sample and an-image of electrical resistivity distribution was generated from current and voltage measurements. We found that the images show the general location of the reinforcing steel and, what`s more important, delineate the absence of the steel. The method may therefore be useful for determining if such steel has been destroyed by corrosion, however to make it useful, the technique must have better resolution so that individual reinforcing steel units are resolved.

  15. Myocardial hypoperfusion on conventional contrast computed tomography.

    PubMed

    Ching, Shing; Chung, Tak Shun

    2015-10-01

    Nonelectrocardiogram (ECG)gated contrast computed tomography (CT) is commonly performed to exclude aortic dissection in chest pain patients. Besides evaluating the aorta for dissection flap, attention should be paid to the myocardium for areas of hypoenhancement that may suggest ischemia. Current models of multidetector CT enable assessment of myocardial perfusion with minimal motion artifact even without ECG gating. Transmural hypoenhancement with preserved wall thickness in a coronary distribution is highly specific for acute myocardial infarction. We report 2 cases of acute chest pain with initial nondiagnostic studies that underwent CT aortogram to exclude dissection. Instead, the CT showed myocardial hypoenhancement in left anterior descending artery territory. Myocardial hypoenhancement occurred before ST-segment elevation on ECG, suggesting that recognition of this important finding may lead to earlier revascularization decisions. PMID:26321167

  16. Diffuse Optical Tomography: Image Reconstruction and Verification

    PubMed Central

    Erfanzadeh, Mohsen; Hosseini, Zeinab; Mohajerani, Ezzedin

    2014-01-01

    Introduction: In this study, we intend to use diffuse optical Tomography (DOT) as a noninvasive, safe and low cost technique that can be considered as a functional imaging method and mention the importance of image reconstruction in accuracy and procession of image. One of the most important and fastest methods in image reconstruction is the boundary element method (BEM). This method is introduced and employed in our works. Method: Generally, to image a biological tissue we must obtain its optical properties. In order to reach this goal we benefit from diffusion equation because tissue is highly scattering medium. Diffusion equation is solved by boundary element equation (BEM) in our research. First, we assume a double layer phantom with different scattering and absorption coefficients to simulate and verify precession and accuracy of image reconstruction by BEM. Light absorption can be affected by volume fraction of blood in skin. For a specific skin species the volume fraction is calculated and then the results are compared with the reconstructed values obtained by BEM. Since the depth of tissue is important in light absorption a two layer phantom with known values is made and the depths of layers are reconstructed by BEM then they are compared with the expected values. A homogenous phantom with known scattering and absorption coefficients was made and then these coefficients were reconstructed by BEM. Finally, an inhomogeneous phantom (phantom with defect) whose defect was in a known position was made and the absorption and scattering coefficients were reconstructed and compared with real values. Results: Comparison between real or simulated values and reconstructed values of scattering and absorption coefficients, volume fraction of blood and thickness of phantom layers by BEM shows maximum errors of 24%, 7% and 35%, respectively. Conclusion: Comparison between BEM data and real or simulated values shows an acceptabl eagreement. Consequently, we can rely on BEM as a beneficial method in diffuse optical tomography image reconstruction. PMID:25606334

  17. Ultrasonic guided wave tomography for ice detection.

    PubMed

    Zhao, Xiang; Rose, Joseph L

    2016-04-01

    Of great concern for many structures, particularly critical sections of rotary and fixed wing aircrafts, is the ability to detect ice either on grounded or in-flight vehicles. As a consequence, some work is reported here that could be useful for a variety of different industries where ice formation is an important problem. This paper presents experimental validations of a probability-based reconstruction algorithm (PRA) on ice detection of plate-like structures. The ice detection tests are performed for three different specimens: a single layer aluminum plate with a circular ice sensing array, a titanium plate with a sparse rectangular ice sensing array, and a carbon-fiber-reinforced titanium plate with an embedded ice sensing array mounted on a carbon fiber back plate. Cases from the simple to the more challenging exemplify that special modes can be used to differentiate ice from water, a sparse rectangular array could also be used for ice detection, and an ice sensing array could be further used to detect the ice on the sensor free side, a very useful application of ice sensing for aircraft wings, for example. Ice detection images for the respective cases are reconstructed to investigate the feasibility of ice sensing with ultrasonic guided wave tomography technology. The results show that the PRA based ultrasonic guided wave tomography method successfully detected and showed ice spots correctly for all three cases. This corroborates the fact that ultrasonic guided wave imaging technology could be a potential useful ice sensing tool in plate-like structures. PMID:26746159

  18. Oscillatory Flow Testing in a Sandbox - Towards Oscillatory Hydraulic Tomography

    NASA Astrophysics Data System (ADS)

    Zhou, Y.; Lim, D.; Cupola, F.; Cardiff, M. A.

    2014-12-01

    Detailed knowledge of subsurface hydraulic properties is important for predicting groundwater flow and contaminant transport. The spatial variation of hydraulic properties in the shallow subsurface has been extensively studied in the past two decades. A recent approach to characterize subsurface properties is hydraulic tomography, in which pressure data from multiple constant-rate pumping tests is inverted using a numerical model. Many laboratory sandbox studies have explored the performance of hydraulic tomography under different controlled conditions and shown that detailed heterogeneity information can be extracted (Liu et al., 2002, Illman et al., 2007, 2008, 2010a, 2010b, Liu et al., 2007, 2008, Xiang et al., 2009, Yin and Illman, 2009, Liu and Kitanidis, 2011, Berg and Illman, 2011a). Recently, Cardiff et al. (2013) proposed a modified approach of Oscillatory Hydraulic Tomography (OHT) - in which periodic pumping signals of different frequencies are used for aquifer stimulation - to characterize aquifer properties. The potential advantages of OHT over traditional hydraulic tomography include: 1) no net injection or extraction of water; 2) little movement of existing contamination; 3) minimal impact of model boundary conditions; and 4) robust extraction of oscillatory signals from noisy data. To evaluate the premise of OHT, we built a highly-instrumented 2-D laboratory sandbox and record pressure responses to periodic pumping tests. In our setup, the laboratory sandbox is filled with sand of known hydraulic properties, and we measure aquifer responses at a variety of testing frequencies. The signals recorded are processed using Fourier-domain analysis, and compared against expected results under linear (Darcian) theory. The responses are analyzed using analytical and numerical models, which provide key insights as to: 1) how "effective" hydraulic properties estimated using homogeneous models are associated with aquifer heterogeneity; and 2) how OHT is able to detect and image aquifer heterogeneity.

  19. Broadband frequency-domain near-infrared spectral tomography using a mode-locked Ti:sapphire laser

    PubMed Central

    Wang, Jia; Jiang, Shudong; Paulsen, Keith D.; Pogue, Brian W.

    2009-01-01

    Frequency-domain near-infrared (NIR) diffuse spectral tomography with a mode-locked Ti:sapphire laser is presented, providing tunable multiwavelength quantitative spectroscopy with maximal power for thick tissue imaging. The system was developed to show that intrinsically high stability can be achieved with many wavelengths in the NIR range, using a mode-locked signal of 80 MHz with heterodyned lock-in detection. The effect of cumulative noise from multiple wavelengths of data on the reconstruction process was studied, and it was shown that inclusion of more wavelengths can reduce skew in the noise distribution. This normalization of the data variance then minimizes errors in estimation of chromophore concentrations. Simulations and tissue phantom experiments were used to quantify this improvement in image accuracy for recovery of tissue hemoglobin and oxygen saturation. PMID:19340109

  20. Multiple evanescent white dot syndrome associated with retinal vasculitis

    PubMed Central

    Takahashi, Akihiro; Saito, Wataru; Hashimoto, Yuki; Ishida, Susumu

    2015-01-01

    Purpose A recent study revealed thickening of the inner retinal layers in acute stage of multiple evanescent white dot syndrome (MEWDS); however, the pathogenesis is still unknown. We report two cases with MEWDS whose funduscopy showed obvious retinal vasculitis. Methods Case reports. Results Healthy myopic 16- and 27-year-old women were the cases under study. In both cases, funduscopic examination revealed multiple, faint, small, subretinal white dots at the posterior pole to the midperiphery and macular granularity oculus dexter. Retinal vascular sheathing was also observed at midperiphery. Late-phase fluorescein angiography revealed leakages corresponding to the vascular sheathing. Enhanced depth imaging optical coherence tomography revealed the discontinuity of the ellipsoid zone corresponding to the white dots and increased macular choroidal thickness. One month later, these white dots and retinal sheathing spontaneously resolved in both cases. Three months later, impairments of the outer retinal morphology and the visual acuity were restored. Conclusion These results suggest that retinal vasculitis possibly plays a role in the pathogenesis of thickened inner retinal layers in acute stage of MEWDS. PMID:26451125