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Sample records for hochaufloesende computertomographie hr-ct

  1. A novel method for 4D cone-beam computer-tomography reconstruction

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Park, Justin C.; Chen, Yunmei; Lan, Guanghui; Lu, Bo

    2015-03-01

    Image quality of Four Dimensional Cone-Beam Computer-Tomography (4DCBCT) is severely impaired by highly insufficient amount of projection data available for each phase. Therefore, making good use of limited projection data is crucial to solve this problem. Noticing that usually only a portion of the images is affected by motion, we separate the moving part (different between phases) of the images from the static part (identical among all phases) with the help of prior image reconstructed using all projection data. Then we update the moving part and the static part of images alternatively through solving minimization problems based on a global (use full projection data) and several local (use projection data for respective phase) linear systems. In the other word, we rebuild a large over-determined linear system for static part from the original under-determined systems and we reduce the number of unknowns in the original system for each phase as well. As a result, image quality for both static part and moving part are greatly improved and reliable 4D CBCT images are then reconstructed.

  2. What HR-CT imaging can teach us about xylem structure and function

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is well established that plant xylem is composed of a complex and interconnected system of vascular elements, but little is known about how the three-dimensional (3D) organization of this network influences properties such as plant hydraulics (Tyree & Zimmermann, 2002), and few studies have measu...

  3. WE-G-207-03: Mask Guided Image Reconstruction (MGIR): A Novel Method for Ultra-Low-Dose 3D and Enhanced 4D Cone-Beam Computer-Tomography

    SciTech Connect

    Park, C; Zhang, H; Chen, Y; Fan, Q; Kahler, D; Li, J; Liu, C; Lu, B

    2015-06-15

    Purpose: Recently, compressed sensing (CS) based iterative reconstruction (IR) method is receiving attentions to reconstruct high quality cone beam computed tomography (CBCT) images using sparsely sampled or noisy projections. The aim of this study is to develop a novel baseline algorithm called Mask Guided Image Reconstruction (MGIR), which can provide superior image quality for both low-dose 3DCBCT and 4DCBCT under single mathematical framework. Methods: In MGIR, the unknown CBCT volume was mathematically modeled as a combination of two regions where anatomical structures are 1) within the priori-defined mask and 2) outside the mask. Then we update each part of images alternatively thorough solving minimization problems based on CS type IR. For low-dose 3DCBCT, the former region is defined as the anatomically complex region where it is focused to preserve edge information while latter region is defined as contrast uniform, and hence aggressively updated to remove noise/artifact. In 4DCBCT, the regions are separated as the common static part and moving part. Then, static volume and moving volumes were updated with global and phase sorted projection respectively, to optimize the image quality of both moving and static part simultaneously. Results: Examination of MGIR algorithm showed that high quality of both low-dose 3DCBCT and 4DCBCT images can be reconstructed without compromising the image resolution and imaging dose or scanning time respectively. For low-dose 3DCBCT, a clinical viable and high resolution head-and-neck image can be obtained while cutting the dose by 83%. In 4DCBCT, excellent quality 4DCBCT images could be reconstructed while requiring no more projection data and imaging dose than a typical clinical 3DCBCT scan. Conclusion: The results shown that the image quality of MGIR was superior compared to other published CS based IR algorithms for both 4DCBCT and low-dose 3DCBCT. This makes our MGIR algorithm potentially useful in various on-line clinical applications. Provisional Patent: UF#15476; WGS Ref. No. U1198.70067US00.

  4. Radiographic study of impact in polymer-bonded explosives

    SciTech Connect

    Fugelso, E.; Jacobson, J.D.; Karpp, R.R.; Jensen, R.

    1981-01-01

    Computer-tomography generated material-density maps from flash x-ray radiographs of the impact of cylinders of mockup polymer-bonded explosive (PBX) striking a steel plate. Comparison of the density fields with computer simulation allowed discrimination of rather complex deformation and flow models for insensitive explosives to be used in further studies of chemical reactions initiated by shock waves.

  5. Erweiterung modellbasierter Segmentierung durch lokale Deformationskriterien

    NASA Astrophysics Data System (ADS)

    Erdt, Marius; Tulchiner, Roman; Sakas, Georgios

    Modellbasierte Ansätze sind heutzutage Stand der Technik zur automatischen Organsegmentierung in medizinischen Bilddatensätzen. In dieser Arbeit wird ein Verfahren vorgestellt, welches die modellbasierte Segmentierung durch lokale Deformationskriterien erweitert, um eine bessere lokale Anpassung der Oberflächenmodelle an Bildstrukturen sowohl hoher als auch niedriger Frequenz zu erreichen. Die beschriebene Methode wird anhand von Computer-Tomographie Datensätzen der Niere beschrieben und evaluiert.

  6. Forensic veterinary radiology: ballistic-radiological 3D computertomographic reconstruction of an illegal lynx shooting in Switzerland.

    PubMed

    Thali, Michael J; Kneubuehl, Beat P; Bolliger, Stephan A; Christe, Andreas; Koenigsdorfer, Urs; Ozdoba, Christoph; Spielvogel, Elke; Dirnhofer, Richard

    2007-08-24

    The lynx, which was reintroduced to Switzerland after being exterminated at the beginning of the 20th century, is protected by Swiss law. However, poaching occurs from time to time, which makes criminal investigations necessary. In the presented case, an illegally shot lynx was examined by conventional plane radiography and three-dimensional multislice computertomography (3D MSCT), of which the latter yielded superior results with respect to documentation and reconstruction of the inflicted gunshot wounds. We believe that 3D MSCT, already described in human forensic-pathological cases, is also a suitable and promising new technique for veterinary pathology.

  7. GRIN-optics-based hyperspectral imaging micro-sensor

    NASA Astrophysics Data System (ADS)

    Zhou, Wei; Leger, James

    2007-09-01

    By utilizing diffractive, refractive and graded-index optics technology, a miniature (1 mm x 1 mm x 2 mm) Computer-Tomography Imaging Spectrometer (CTIS) sensor has been designed with 16 independent optical channels working in a snap-shot mode for hyper-spectral imaging. The designed prototype covers a 400~700 nm wavelength range. One optical channel has been fabricated and characterized. By azimuthally rotating this optical channel along the optical axis and collecting different dispersed images to simulate the full sensor read-out, the full hyperspectral detection scheme has been demonstrated.

  8. [A rare complication during the surgical removal of an impacted maxillary third molar].

    PubMed

    Hoekema, A; Apperloo, R C; de Lange, J

    2012-01-01

    A 12-year-old boy was referred by his orthodontist due to the dysmorphic condition of the impacted teeth 18 and 28. Because teeth 17 and 27 were close related to the third molars, the decision was made to remove the impacted teeth under general anaesthesia. During luxation of tooth 28, it was accidentally displaced deeper into the socket. The tooth could still not be localized after the use of radiographs, an antrostomy, and surgical exploration. It was decided to leave the 28 in its place and to perform cone beam computertomography. This showed that tooth 28 was displaced into the infratemporal fossa. Since the patient was free of symptoms, a period of watchful waiting was initiated. A control visit and cone beam computertomography 9 months postoperatively revealed no signs or symptoms or changes in the position of the displaced tooth. It was therefore decided to leave the third molar in its displaced position. Displacement of a maxillary third molar into the infratemporal fossa is considered a rare complication.

  9. Advanced imaging assessment of bone quality.

    PubMed

    Genant, Harry K; Jiang, Yebin

    2006-04-01

    Noninvasive and/or nondestructive techniques can provide structural information about bone, beyond simple bone densitometry. While the latter provides important information about osteoporotic fracture risk, many studies indicate that bone mineral density (BMD) only partly explains bone strength. Quantitative assessment of macrostructural characteristics, such as geometry, and microstructural features, such as relative trabecular volume, trabecular spacing, and connectivity, may improve our ability to estimate bone strength. Methods for quantitatively assessing macrostructure include (besides conventional radiographs) dual X ray absorptiometry (DXA) and computed tomography (CT), particularly volumetric quantitative computed tomography (vQCT). Methods for assessing microstructure of trabecular bone noninvasively and/or nondestructively include high-resolution computed tomography (hrCT), microcomputed tomography (micro-CT), high-resolution magnetic resonance (hrMR), and micromagnetic resonance (micro-MR). vQCT, hrCT, and hrMR are generally applicable in vivo; micro-CT and micro-MR are principally applicable in vitro. Despite progress, problems remain. The important balances between spatial resolution and sampling size, or between signal-to-noise and radiation dose or acquisition time, need further consideration, as do the complexity and expense of the methods versus their availability and accessibility. Clinically, the challenges for bone imaging include balancing the advantages of simple bone densitometry versus the more complex architectural features of bone, or the deeper research requirements versus the broader clinical needs. The biological differences between the peripheral appendicular skeleton and the central axial skeleton must be further addressed. Finally, the relative merits of these sophisticated imaging techniques must be weighed with respect to their applications as diagnostic procedures, requiring high accuracy or reliability, versus their monitoring

  10. Assessment of interstitial lung disease in Sjögren's syndrome by lung ultrasound: a pilot study of correlation with high-resolution chest tomography.

    PubMed

    Vasco, Pablo Guisado; de Luna Cardenal, Gonzalo; Garrido, Isabel Martín; Pinilla, José Manuel Luque; Rodríguez, Guadalupe Fraile; Mateo, Juan José Nava; Ruiz, Daniel Carnevalli

    2016-11-29

    The background of this study is to assess the accuracy of lung ultrasound (LUS) to diagnose interstitial lung disease (ILD) in Sjögren's syndrome (Sjs), in patients who have any alterations in pulmonary function tests (PFT) or respiratory symptoms. LUS was correlated with chest tomography (hrCT), considering it as the imaging gold standard technique to diagnose ILD. This is a pilot, multicenter, cross-sectional, and consecutive-case study. The inclusion criteria are ≥18 years old, Signs and symptoms: according to ACEG 2002 criteria, respiratory symptoms (dyspnea, cough), or any alterations in PFR. LUS was done following the International Consensus Conference on Lung Ultrasound protocol for interstitial syndrome (B pattern). Of the 50 patients in follow-up, 13 (26%) met the inclusion criteria. All were women with age 63.62 years (range 39-88). 78.6% of the cases had primary Sjs (SLE, RA, n = 2). The intra-rater reliability k is 1, according to Gwet's Ac1 and GI index (probability to concordance-e(K)-, by Cohen, of 0.52). LUS has a sensitivity of 1 (95% CI 0.398-1.0), specificity of 0.89 (95% CI 0.518-0.997), and a positive probability reason of 9.00 (95% CI 7.1-11.3) to detect ILD. The correlation of Pearson is r = 0.84 (p < 0.001). To check the accuracy of LUS to diagnose ILD, a completely bilateral criterion of yes/no for interstitial pattern was chosen, AUC reaches significance, 0.94 (0.07) (95% CI 0.81-1.0, p = 0.014). LUS reaches an excellent correlation to hrCT in Sjs affected with ILD, and might be a useful technique in daily clinical practice for the assessment of pulmonary disease in the sicca syndrome.

  11. [The differential diagnosis in Menières disease: the basilar impression (author's transl)].

    PubMed

    Elies, W

    1978-11-22

    We examined the cranio-cervical region in 180 patients with nonspecific dizziness and in most cases unilateral sensory-neural hearing loss. In 32 cases we found malformations of the cranio-cervical region. The sympatomatology of the basilar impression is probably caused by the compression of the vessels of the lower cerebellar regions and the brain stem as well as disturbances of the cerebro-spinal fluid circulation. The basilar impression is diagnosed by means of lateral X-rays of the skull base, tomography of this region and in some cases computertomography of the posterior cranial fossa. The importance of basilar impression in the differential diagnosis of Menières disease and acoustic neuroma is discussed.

  12. [Technology integration and process management. Concept and implementation of a new platform for simultaneous diagnosis and therapy of acutely ill and injured patients and for elective computer assisted surgery (CAS)].

    PubMed

    Messmer, P; Jacob, A L; Fries, E; Gross, T; Suhm, N; Steinbrich, W; Frede, K E; Schneider, T; Regazzoni, P

    2001-10-01

    Modern imaging and computer technology gain more and more importance in surgery. This is true for elective and emergency diagnosis and treatment. However integration of technology and optimization of process management is severely behind. A new diagnostic-therapeutic platform should balance this deficit. The platform is composed of a fully equipped operation room environment with integrated high end computer-tomography with navigation, a digital subtraction angiography and an OR- and imaging-table particularly developed for this set-up. The platform may be used for elective diagnosis, for diagnosis and therapy in polytraumatized patients in one and the same location (one stop shop) and for computer assisted surgery (CAS). Bringing the technology to the patient and not the patient to the technology can save time consuming and potentially dangerous transports and expensive personnel can be reduced. Navigation-technology and high quality intra-operative imaging expand the spectrum of minimally invasive surgery.

  13. Advanced imaging of the macrostructure and microstructure of bone

    NASA Technical Reports Server (NTRS)

    Genant, H. K.; Gordon, C.; Jiang, Y.; Link, T. M.; Hans, D.; Majumdar, S.; Lang, T. F.

    2000-01-01

    Noninvasive and/or nondestructive techniques are capable of providing more macro- or microstructural information about bone than standard bone densitometry. Although the latter provides important information about osteoporotic fracture risk, numerous studies indicate that bone strength is only partially explained by bone mineral density. Quantitative assessment of macro- and microstructural features may improve our ability to estimate bone strength. The methods available for quantitatively assessing macrostructure include (besides conventional radiographs) quantitative computed tomography (QCT) and volumetric quantitative computed tomography (vQCT). Methods for assessing microstructure of trabecular bone noninvasively and/or nondestructively include high-resolution computed tomography (hrCT), micro-computed tomography (muCT), high-resolution magnetic resonance (hrMR), and micromagnetic resonance (muMR). vQCT, hrCT and hrMR are generally applicable in vivo; muCT and muMR are principally applicable in vitro. Although considerable progress has been made in the noninvasive and/or nondestructive imaging of the macro- and microstructure of bone, considerable challenges and dilemmas remain. From a technical perspective, the balance between spatial resolution versus sampling size, or between signal-to-noise versus radiation dose or acquisition time, needs further consideration, as do the trade-offs between the complexity and expense of equipment and the availability and accessibility of the methods. The relative merits of in vitro imaging and its ultrahigh resolution but invasiveness versus those of in vivo imaging and its modest resolution but noninvasiveness also deserve careful attention. From a clinical perspective, the challenges for bone imaging include balancing the relative advantages of simple bone densitometry against the more complex architectural features of bone or, similarly, the deeper research requirements against the broader clinical needs. The

  14. Bone fragility and imaging techniques

    PubMed Central

    D’Elia, Giovanni; Caracchini, Giuseppe; Cavalli, Loredana; Innocenti, Paolo

    2009-01-01

    Bone fragility is a silent condition that increases bone fracture risk, enhanced by low bone mass and microarchitecture deterioration of bone tissue that lead to osteoporosis. Fragility fractures are the major clinical manifestation of osteoporosis. A large body of epidemiological data indicates that the current standard for predicting fragility fracture risk is an areal BMD (aBMD) measurement by DXA. Although mineral density measurements assess the quantity of bone, the quality of the tissue is an important predictor of fragility. Thus, bone strength is explained not only by BMD but also by macrostructural and microstructural characteristics of bone tissue. Imaging diagnostics, through the use of X-rays, DXA, Ultrasonography, CT and MR, provides methods for diagnosis and characterization of fractures, and semi- and quantitative methods for assessment of bone consistency and strength, that become precious for bone fragility clinical management if they are integrated by clinical risk factors. The last employment of sophisticated non-invasively imaging techniques in clinical research as high-resolution CT (hrCT), microCT (μ-CT), high-resolution MR (hrMR) and, microRM (μRM), combined with finite element analysis methods, open to new challenges in a better bone strength assessment to enhance the comprehension of biomechanical parameters and the prediction of fragility fractures. PMID:22461252

  15. Quantitative imaging methods in osteoporosis

    PubMed Central

    Oei, Ling; Koromani, Fjorda; Rivadeneira, Fernando; Zillikens, M. Carola

    2016-01-01

    Osteoporosis is characterized by a decreased bone mass and quality resulting in an increased fracture risk. Quantitative imaging methods are critical in the diagnosis and follow-up of treatment effects in osteoporosis. Prior radiographic vertebral fractures and bone mineral density (BMD) as a quantitative parameter derived from dual-energy X-ray absorptiometry (DXA) are among the strongest known predictors of future osteoporotic fractures. Therefore, current clinical decision making relies heavily on accurate assessment of these imaging features. Further, novel quantitative techniques are being developed to appraise additional characteristics of osteoporosis including three-dimensional bone architecture with quantitative computed tomography (QCT). Dedicated high-resolution (HR) CT equipment is available to enhance image quality. At the other end of the spectrum, by utilizing post-processing techniques such as the trabecular bone score (TBS) information on three-dimensional architecture can be derived from DXA images. Further developments in magnetic resonance imaging (MRI) seem promising to not only capture bone micro-architecture but also characterize processes at the molecular level. This review provides an overview of various quantitative imaging techniques based on different radiological modalities utilized in clinical osteoporosis care and research. PMID:28090446

  16. Quantitative imaging methods in osteoporosis.

    PubMed

    Oei, Ling; Koromani, Fjorda; Rivadeneira, Fernando; Zillikens, M Carola; Oei, Edwin H G

    2016-12-01

    Osteoporosis is characterized by a decreased bone mass and quality resulting in an increased fracture risk. Quantitative imaging methods are critical in the diagnosis and follow-up of treatment effects in osteoporosis. Prior radiographic vertebral fractures and bone mineral density (BMD) as a quantitative parameter derived from dual-energy X-ray absorptiometry (DXA) are among the strongest known predictors of future osteoporotic fractures. Therefore, current clinical decision making relies heavily on accurate assessment of these imaging features. Further, novel quantitative techniques are being developed to appraise additional characteristics of osteoporosis including three-dimensional bone architecture with quantitative computed tomography (QCT). Dedicated high-resolution (HR) CT equipment is available to enhance image quality. At the other end of the spectrum, by utilizing post-processing techniques such as the trabecular bone score (TBS) information on three-dimensional architecture can be derived from DXA images. Further developments in magnetic resonance imaging (MRI) seem promising to not only capture bone micro-architecture but also characterize processes at the molecular level. This review provides an overview of various quantitative imaging techniques based on different radiological modalities utilized in clinical osteoporosis care and research.

  17. Effects of cardiotrophin-1 on haemodynamics and cardiac function in conscious rats.

    PubMed

    Jin, H; Yang, R; Ko, A; Pennica, D; Wood, W I; Paoni, N F

    1998-01-01

    Cardiotrophin-1 (CT-1), a newly discovered cytokine, has been shown to induce cardiac hypertrophy in vitro and in vivo. The present study examined the effects of CT-1 on haemodynamics and cardiac function. The measurements of haemodynamic parameters were made using in-dwelling catheters and flow probes in conscious, unrestrained rats. Intravenous administration of CT-1 caused a dose-dependent decrease in mean arterial pressure (MAP), and an increase in heart rate (HR). CT-1 (100 micrograms/kg) significantly elevated cardiac output and HR, and decreased MAP and systemic vascular resistance. Stroke volume was unaltered, suggesting that the CT-1 induced increase in cardiac output was secondary to increased HR. There was no significant difference in left ventricular maximal dP/dt between the CT-1-treated and vehicle-treated groups, suggesting that CT-1 might not induce a meaningful change in ventricular contractility. Pretreatment with intravenous N omega-nitro-L-arginine methyl ester, a specific inhibitor of nitric oxide synthase, significantly attenuated the depressor and tachycardic responses to CT-1. These results indicate that nitric oxide plays an important role in mediating the haemodynamic effects of CT-1.

  18. Traumatic diaphragmatic ruptures: clinical presentation, diagnosis and surgical approach in adults.

    PubMed

    Hofmann, Sabine; Kornmann, Marko; Henne-Bruns, Doris; Formentini, Andrea

    2012-01-01

    Einleitung: Zwerchfellhernien sind selten, aber potentiell lebensgefährlich durch Hernierung von intraabdominellen Organen in die Pleurahöhlen. Sie können in der initialen Diagnostik leicht übersehen werden und meist ist ein dringender klinischer Verdacht notwendig, um die Diagnose zu stellen. Ziel dieser retrospektiven Studie war es, das klinische Bild, diagnostische Methoden und die chirurgische Vorgehensweise in Bezug auf Patienten mit Zwerchfellrupturen, die an unserem Institut behandelt wurden, zu evaluieren.Methoden: Eine retrospektive Studie wurde durchgeführt, um unsere Erfahrungen mit Patienten mit traumatischer Zwerchfellruptur zu untersuchen. Krankenakten wurden hinsichtlich Alter, Geschlecht, Seitenlokalisation, Begleitverletzungen, chirurgischem Vorgehen, Diagnostik, Zeitspanne bis zur Diagnosestellung und klinischen Ergebnissen ausgewertet.Ergebnisse: 14 Patienten (medianes Alter: 46 Jahre, Spanne: 18–71 Jahre, 9 männlich, 5 weiblich) wurden mit der Diagnose einer traumatischen Zwerchfellruptur (rechte Seite: 4, linke Seite 10) wurden in unserer Klinik im Zeitraum von Juli 2003 bis September 2011 operativ behandelt. Unfallmechanismen waren penetrierend (14%), stumpf (50%) und andere (36%). Assoziierte Abdominalverletzungen beinhalteten die Milzruptur (n=3), Leberruptur (n=2), Bauchwandverletzung (n=2) und Magenperforation (n=1). Computertomographie war die Untersuchungsmethode mit der höchsten Sensitivität. Alle Patienten wurden über einen transabdominellen Zugang operiert, 10 erhielten einen Verschluß des Defektes mittels direkter Naht, 4 wurden mit einem Kunststoffnetz versorgt. Assoziierte Baucheingriffe beinhalteten die Splenektomie (n=3), „Packing“ der Leber (n=2), Bauchwandrekonstruktion (n=2) und Magenteilresektion (n=1). Morbidität und Mortalität während des stationären Aufenthaltes betrugen 36% und 0%. Der mediane postoperative Krankenhausaufenthalt waren 17 Tage (zwischen 7 und 40 Tagen).Schlussfolgerung: Morbidität und

  19. A coin-like peripheral small cell lung carcinoma associated with acute paraneoplastic axonal Guillain-Barre-like syndrome.

    PubMed

    Jung, Ioan; Gurzu, Simona; Balasa, Rodica; Motataianu, Anca; Contac, Anca Otilia; Halmaciu, Ioana; Popescu, Septimiu; Simu, Iunius

    2015-06-01

    A 65-year-old previously healthy male heavy smoker was hospitalized with a 2-week history of progressive muscle weakness in the lower and upper extremities. After 10 days of hospitalization, urinary sphincter incompetence and fecal incontinence were added and tetraparesis was established. The computer-tomography scan examination revealed a massive right hydrothorax and multifocal solid acinar structures with peripheral localization in the left lung, which suggested pulmonary cancer. Bone marrow metastases were also suspected. Based on the examination results, the final diagnosis was acute paraneoplastic axonal Guillain-Barre-like syndrome. The patient died 3 weeks after hospitalization. At autopsy, bronchopneumonia and a right hydrothorax were confirmed. Several 4 to 5-mm-sized round peripherally located white nodules were identified in the left lung, without any central tumor mass. Under microscope, a coin-shaped peripheral/subpleural small cell carcinoma was diagnosed, with generalized bone metastases. A huge thrombus in the abdominal aorta and acute pancreatitis was also seen at autopsy. This case highlights the difficulty of diagnosis of lung carcinomas and the necessity of a complex differential diagnosis of severe progressive ascending neuropathies. This is the 6th reported case of small cell lung cancer-associated acute Guillain-Barre-like syndrome and the first report about an association with a coin-like peripheral pattern.

  20. Structural analysis of paintings based on brush strokes

    NASA Astrophysics Data System (ADS)

    Sablatnig, Robert; Kammerer, Paul; Zolda, Ernestine

    1998-05-01

    The origin of works of art can often not be attributed to a certain artist. Likewise it is difficult to say whether paintings or drawings are originals or forgeries. In various fields of art new technical methods are used to examine the age, the state of preservation and the origin of the materials used. For the examination of paintings, radiological methods like X-ray and infra-red diagnosis, digital radiography, computer-tomography, etc. and color analyzes are employed to authenticate art. But all these methods do not relate certain characteristics in art work to a specific artist -- the artist's personal style. In order to study this personal style of a painter, experts in art history and image processing try to examine the 'structural signature' based on brush strokes within paintings, in particular in portrait miniatures. A computer-aided classification and recognition system for portrait miniatures is developed, which enables a semi- automatic classification and forgery detection based on content, color, and brush strokes. A hierarchically structured classification scheme is introduced which separates the classification into three different levels of information: color, shape of region, and structure of brush strokes.

  1. [Update - health risks induced by ionizing radiation from diagnostic imaging].

    PubMed

    Knüsli, Claudio; Walter, Martin

    2013-12-01

    Ionizing radiation is the most thoroughly investigated exogenous noxa. Since the early 20th century it is well known that using ionizing radiation in diagnostic procedures causes cancer - physicians themselves frequently being struck by this disease in those early days of radiology. Radiation protection therefore plays an important role. Below doses of 100 Millisievert (mSv) however much research has to be accomplished yet because not only malignant tumors, but cardiovascular diseases, malformations and genetic sequelae attributable to low dose radiation have been described. Unborns, children and adolescents are highly vulnerable. Dose response correlations are subject to continuing discussions because data stem mostly from calculations studying Japanese atomic bomb survivors. Radiation exposure is not exactly known, and it is unknown, if observations of radiation induced diseases in this ethnicity can be generalized. Nowadays the main source of low dose ionizing radiation from medical diagnostics is due to computertomography (CT). Large recent clinical studies from the UK and Australia investigating cancer incidence after exposition to CT in childhood and adolescence confirm that low doses in the range of 5 mSv already significantly increase the risk of malignant diseases during follow up. Imaging techniques as ultrasound and magnetic resonance tomography therefore should be preferred whenever appropriate.

  2. CtIP Protein Dimerization Is Critical for Its Recruitment to Chromosomal DNA Double-stranded Breaks*

    PubMed Central

    Wang, Hailong; Shao, Zhengping; Shi, Linda Z.; Hwang, Patty Yi-Hwa; Truong, Lan N.; Berns, Michael W.; Chen, David J.; Wu, Xiaohua

    2012-01-01

    CtIP (CtBP-interacting protein) associates with BRCA1 and the Mre11-Rad50-Nbs1 (MRN) complex and plays an essential role in homologous recombination (HR)-mediated DNA double-stranded break (DSB) repair. It has been described that CtIP forms dimers in mammalian cells, but the biological significance is not clear. In this study, we identified a conserved motif in the N terminus of CtIP, which is required for dimer formation. We further showed that CtIP mutants impaired in forming dimers are strongly defective in HR, end resection, and activation of the ataxia telangiectasia and Rad3-related pathway, without notable change of CtIP interactions with BRCA1 or Nbs1. In addition to HR, CtIP dimerization is also required for microhomology-mediated end joining. Live cell imaging of enhanced GFP-tagged CtIP demonstrates that the CtIP dimerization mutant fails to be localized to DSBs, whereas placing a heterologous dimerization motif to the dimerization mutant restores CtIP recruitment to DSBs. These studies suggest that CtIP dimer formation is essential for its recruitment to DSBs on chromatin upon DNA damage. Furthermore, DNA damage-induced phosphorylation of CtIP is significantly reduced in the CtIP dimerization mutants. Therefore, in addition to the C-terminal conserved domains critical for CtIP function, the dimerization motif on the N terminus of CtIP is also conserved and essential for its function in DNA damage responses. The severe repair defects of CtIP dimerization mutants are likely due to the failure in localization to chromosomal DSBs upon DNA damage. PMID:22544744

  3. Computer-aided design and custom-made guide in corrective osteotomy for complex femoral deformity.

    PubMed

    Chai, Wei; Xu, Meng; Zhang, Guo-qiang; Zhang, Li-hai; Gou, Wen-long; Ni, Ming; Chen, Ji-ying

    2013-06-01

    Preoperative planning of corrective osteotomy with traditional radiography has limitations in regards to determining the ideal osteotomy location and orientation in three-dimensional femoral deformities. Though a successful operation can be planned preoperatively, intraoperative contingencies might adhere to the procedural plan in the performance of operation. To efficiently perform a planned procedure, proposed is a design to implement three-dimensional reconstruction photography, based on computer-tomography (CT) scan. A custom-made guide was designed to navigate the osteotomy as planned, and additionally, a personalized intramedullary nail was used for fixation after osteotomy. Three-dimensional (3D) photography of deformed femur was established based on the CT dataset and transferred into 3D photography processing software for further planning. Osteotomy planes were designed and adjusted at deformity sites to correct the 3D deformities. The methodology of a custom-made osteotomy guide was introduced in femoral corrective osteotomy, for the first time, to navigate the operation as planned. After the virtual osteotomy and reduction of bone segments, the parameters of a custom-made intramedullary nail were measured for manufacturing. Findings Virtual operation in computer shows complete correction of the 3D deformity. The osteotomy guide, obtained by rapid-prototyping techniques, navigates mimicking surgery on rapid-prototyping model of the involved femur as planned. Internal fixation was achieved using the custom-made intramedullary nail. Interpretation three-dimensional visualization introduces an advantage in preoperative planning for corrective osteotomy of 3D femoral deformity, and the custom-made osteotomy guide is crucial to realize such a deliberate plan during the actual procedures. The internal fixator, such as an intramedullary nail, can be modified or personalized for fixation in unique cases.

  4. In vivo behavior of surface modified Ti6Al7Nb alloys used in selective laser melting for custom-made implants. A preliminary study.

    PubMed

    Rotaru, H; Armencea, G; Spîrchez, Diana; Berce, C; Marcu, Teodora; Leordean, D; Kim, Seong Gon; Lee, Sang Woon; Dinu, C; Băciuţ, G; Băciuţ, Mihaela

    2013-01-01

    The objectives of this study were to test the biocompatibility and to evaluate the osseointegration of Titanium-Aluminum-Niobium (Ti6Al7Nb) alloy used in the manufacturing of personalized implants with selective laser melting (SLM) technology and to compare the growth viability of osteoblastic-like cells on different Ti6Al7Nb alloy samples (plain, coated with hydroxyapatite or SiO2-TiO2) implanted into the cranial bone of Wistar rats. In terms of biocompatibility, the cone-beam computer-tomography head scans taken at the moment of sacrifice of each group (one, two and three months) showed no implant displacement, no osteolysis and no liquid collection around the implants. At one month, around all types of implants new bone formation was noticed, although around the plain Ti6Al7Nb implant a large amount of powder debris was present. Still, no inflammatory reaction was seen. At two months, the distance between the implants and the calvarial bone margins diminished. A thin layer of fibrous tissue was noticed around the Ti6Al7Nb implant coated with hydroxyapatite but no bone contact was achieved. In the group sacrificed at three months there was still no bone contact, but noticeable were the SiO2-TiO2. In the group sacrificed at three months SiO2-TiO2 particles detached from the implant and completely integrated in the tissue were noticeable. All results suggested that the Ti6Al7Nb alloy with or without infiltration is well biologically tolerated.

  5. High-resolution arthrosonography of the temporomandibular joint with video and computer support

    NASA Astrophysics Data System (ADS)

    Sader, Robert; Zeilhofer, Hans-Florian U.; Deppe, Herbert; Horch, Hans-Henning; Kling, Bettina

    1995-05-01

    Ultrasound imaging of the temporomandibular joint has been problematic due to the lower frequency of the transducers used up to the present time. Imaging of temporomandibular joint structures being utilizable for diagnosis and therapy was only possible through time-consuming and expensive radiological image yielding procedures (computertomography, magnetic resonance imaging). 84 temporomandibular joints in 42 patients were examined clinically, radiologically, by axiographic tracing, magnetic resonance imaging and ultrasound imaging. An ultrasound unit was used with a high- frequency 13MHz transducer. The temporomandibular joint was examined preauricularily; by this the lateral section of the joint could be represented. The image sequences in functional condylus movements were taped via a video output into a film recorder. Selected ultrasound images from the beginning to the end of the movement could then be digitalized and read into a personal computer to be evaluated. The computer then calculated a line of movement and the angle of the joint's course. By ultrasound imaging the joint space could be represented and measured clearly. Compared with the space measured in the magnetic resonance image the value determined by ultrasonography was a tenth power more exact. The computer-supported image analysis of the condylus movements led to an exact presentation of the condylus course. The sonographically determined condylar guidance corresponded to the value traced by axiography with high significance within a range of 3 degrees. The temporomandibular joint's disc could be localized just as exactly as with the magnetic resonance imaging. The use of a 13MHz transducer offers a new low-cost method of noninvasive dynamic imaging of important temporomandibular joint structures. The possibility of video and computer support enables movement analysis and opens new possibilities in the morphological and functional evaluation of the temporomandibular joint.

  6. Spontaneous aortoenteric fistula involving the sigmoid: A case report and review of literature

    PubMed Central

    Karthaus, Eleonora G.; Post, Ivo C.J.H.; Akkersdijk, George J.M.

    2015-01-01

    Introduction Primary aortoenteric fistula (PAEF) is a pathological communication between the aorta and any portion of the gastrointestinal tract. The pathology is very rare and easily overlooked during the diagnostic process. Presentation of Case We report the exceptional case of an 86-year-old man with episodes of abdominal pain and rectal bleeding of unknown cause over a period of 1,5 months due to a PAEF to the sigmoid. A sigmoidectomy was performed and a rifampicin-soaked aortic graft was placed. The patient had an uneventful post-operative recovery. The duration of symptoms, the anatomic location of the fistula and the outcome after surgery makes this case unique. Discussion With an incidence of 0.04–0.07% in all patients with aortic aneurysms a PAEF is very rare. Only 2% of PAEF's involves the sigmoid. The most common cause is an atherosclerotic aortic aneurysm. Patients with PAEF can present with a triad of symptoms including gastrointestinal bleeding, abdominal pain and a pulsating mass. A contrast-enhanced computer-tomography scan (CTa) is the most accurate tool to demonstrate a PAEF. Without a strong clinical suspicion, diagnosing a PAEF is hard and frequently delayed. The overall PAEF-related mortality is high (61–100%) and decreases after surgery (30–40%). Conclusion A primary aortoenteric fistula involving the sigmoid is very rare. Clinical presentation can vary, diagnosis can be difficult and surgical options may differ. Even with low suspicion of PAEF, we recommend performing a CTa. With a high overall mortality of more than 60% due to exsanguinating, surgical treatment is always indicated. PMID:26741274

  7. On the development of the chondrocranium and the histological anatomy of the head in perinatal stages of marsupial mammals.

    PubMed

    Sánchez-Villagra, Marcelo R; Forasiepi, Analía M

    2017-01-01

    non-classical model organisms, and integration with imaging and sectional data derived from computer-tomography.

  8. Toxic inner ear lesion following otitis media with effusion: a comparative CT-study regarding the morphology of the inner ear.

    PubMed

    Wilhelm, Thomas; Stelzer, Tim; Wiegand, Susanne; Güldner, Christian; Teymoortash, Afshin; Günzel, Thomas; Hagen, Rudolf

    2015-12-01

    Viral infections of the upper respiratory airways can lead to a delayed viral otitis media (VOM) caused by a diffusion of viruses/virus particles through the round window membrane and resulting in sensorineural hearing loss. The treatment of choice is immediate paracentesis, evacuation of all fluids from the middle ear cavity, and haemorrheological infusions. However, in some cases, persistent symptoms may be an indication for a surgical approach using mastoidectomy. In high-resolution computed tomography, an extended small-sized pneumatisation of the mastoid cells with complete shading was found in these non-responsive cases. Therefore, a direct means of inner ear affliction through weak parts of the labyrinthine bone may be hypothesised. Patients suffering from a toxic inner ear lesion (TIEL) following a common cold, treated over a 10-year period in a Tertiary Care Centre (N = 52, 57 ears), were identified and the morphological characteristics of the temporal bones of affected patients were examined by means of high-resolution computed tomography (hrCT). The findings were compared with a matched control group of 64 normal ears (CONT). Measurements included the grade of pneumatisation, distances within the temporal bones and Hounsfield units (HU) at defined anatomical structures. In the TIEL group, we found a small-sized pneumatisation in 79.4 % and a medium-sized pneumatisation in 10.9 %, thus differing from the CONT group and the literature data. Thickness of the bone wall of the lateral semicircular canal (LSC) and distances within the aditus ad antrum were significantly reduced in the TIEL group. HU's were markedly lower in the TIEL group at the precochlea, the LSC, and dorsolateral to the promentia of the LSC. There was a correlation between the HU's at the prominentia of the LSC and the hearing loss (p = 0.002). Persisting interosseous globuli, as described in 1897 by Paul Manasse, form an osseochondral network within the otic capsule and may be responsible

  9. Can the risk of secondary cancer induction after breast conserving therapy be reduced using intraoperative radiotherapy (IORT) with low-energy x-rays?

    PubMed Central

    2011-01-01

    Background Radiation induced secondary cancers are a rare but severe late effect after breast conserving therapy. Intraoperative radiotherapy (IORT) is increasingly used during breast conserving surgery. The purpose of this analysis was to estimate secondary cancer risks after IORT compared to other modalities of breast radiotherapy (APBI - accelerated partial breast irradiation, EBRT - external beam radiotherapy). Methods Computer-tomography scans of an anthropomorphic phantom were acquired with an INTRABEAM IORT applicator (diameter 4 cm) in the outer quadrant of the breast and transferred via DICOM to the treatment planning system. Ipsilateral breast, contralateral breast, ipsilateral lung, contralateral lung, spine and heart were contoured. An INTRABEAM source (50 kV) was defined with the tip of the drift tube at the center of the spherical applicator. A dose of 20 Gy at 0 mm depth from the applicator surface was prescribed for IORT and 34 Gy (5 days × 2 × 3.4 Gy) at 10 mm depth for APBI. For EBRT a total dose of 50 Gy in 2 Gy fractions was planned using two tangential fields with wedges. The mean and maximal doses, DVHs and volumes receiving more than 0.1 Gy and 4 Gy of organs at risk (OAR) were calculated and compared. The life time risk for secondary cancers was estimated according to NCRP report 116. Results IORT delivered the lowest maximal doses to contralateral breast (< 0.3 Gy), ipsilateral (1.8 Gy) and contralateral lung (< 0.3 Gy), heart (1 Gy) and spine (< 0.3 Gy). In comparison, maximal doses for APBI were 2-5 times higher. EBRT delivered a maximal dose of 10.4 Gy to the contralateral breast and 53 Gy to the ipsilateral lung. OAR volumes receiving more than 4 Gy were 0% for IORT, < 2% for APBI and up to 10% for EBRT (ipsilateral lung). The estimated risk for secondary cancer in the respective OAR is considerably lower after IORT and/or APBI as compared to EBRT. Conclusions The calculations for maximal doses and volumes of OAR suggest that the risk

  10. Consistent Evaluation of ACOS-GOSAT, BESD-SCIAMACHY, CarbonTracker, and MACC Through Comparisons to TCCON

    NASA Technical Reports Server (NTRS)

    Kulawik, Susan; Wunch, Debra; O’Dell, Christopher; Frankenberg, Christian; Reuter, Maximilian; Chevallier, Frederic; Oda, Tomohiro; Sherlock, Vanessa; Buchwitz, Michael; Osterman, Greg; Miller, Charles E.; Iraci, Laura T.; Wolf, Joyce

    2016-01-01

    -to-year variability of 0.3 parts per million, with biases larger than the TCCON predicted bias uncertainty of 0.4 parts per million at many stations. We find that GOSAT and CT2013b under-predict the seasonal cycle amplitude in the Northern Hemisphere (NH) between 46 and 53 degrees North latitude, MACC over-predicts between 26 and 37 degrees North latitude, and CT2013b under-predicts the seasonal cycle amplitude in the Southern Hemisphere (SH). The seasonal cycle phase indicates whether a data set or model lags another data set in time. We find that the GOSAT measurements improve the seasonal cycle phase substantially over the prior while SCIAMACHY measurements improve the phase significantly for just two of seven sites. The models reproduce the measured seasonal cycle phase well except for at Lauder_125HR (CT2013b) and Darwin (MACC). We compare the variability within 1 day between TCCON and models in June-July-August; there is correlation between 0.2 and 0.8 in the NH, with models showing 10-50 percent the variability of TCCON at different stations and CT2013b showing more variability than MACC. This paper highlights findings that provide inputs to estimate flux errors in model assimilations, and places where models and satellites need further investigation, e.g., the SH for models and 45-67 degrees North latitude for GOSAT and CT2013b.

  11. Consistent evaluation of ACOS-GOSAT, BESD-SCIAMACHY, CarbonTracker, and MACC through comparisons to TCCON

    NASA Astrophysics Data System (ADS)

    Kulawik, Susan; Wunch, Debra; O'Dell, Christopher; Frankenberg, Christian; Reuter, Maximilian; Oda, Tomohiro; Chevallier, Frederic; Sherlock, Vanessa; Buchwitz, Michael; Osterman, Greg; Miller, Charles E.; Wennberg, Paul O.; Griffith, David; Morino, Isamu; Dubey, Manvendra K.; Deutscher, Nicholas M.; Notholt, Justus; Hase, Frank; Warneke, Thorsten; Sussmann, Ralf; Robinson, John; Strong, Kimberly; Schneider, Matthias; De Mazière, Martine; Shiomi, Kei; Feist, Dietrich G.; Iraci, Laura T.; Wolf, Joyce

    2016-02-01

    -predicted bias uncertainty of 0.4 ppm at many stations. We find that GOSAT and CT2013b underpredict the seasonal cycle amplitude in the Northern Hemisphere (NH) between 46 and 53° N, MACC overpredicts between 26 and 37° N, and CT2013b underpredicts the seasonal cycle amplitude in the Southern Hemisphere (SH). The seasonal cycle phase indicates whether a data set or model lags another data set in time. We find that the GOSAT measurements improve the seasonal cycle phase substantially over the prior while SCIAMACHY measurements improve the phase significantly for just two of seven sites. The models reproduce the measured seasonal cycle phase well except for at Lauder_125HR (CT2013b) and Darwin (MACC). We compare the variability within 1 day between TCCON and models in JJA; there is correlation between 0.2 and 0.8 in the NH, with models showing 10-50 % the variability of TCCON at different stations and CT2013b showing more variability than MACC. This paper highlights findings that provide inputs to estimate flux errors in model assimilations, and places where models and satellites need further investigation, e.g., the SH for models and 45-67° N for GOSAT and CT2013b.