954 resultados para 110320 Radiology and Organ Imaging


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Purpose: To evaluate the accuracy of approximal caries detection comparing enhanced and unenhanced Sidexis CCD-based digital image with Ektaspeed Plus and INSIGHT films. Methods: Fifty-two extracted premolars were imaged under identical standardized geometric and exposure conditions. Four observers, using five points confidence scale, rated 104 approximal surfaces for the presence or absence of carious lesions by means of four image modalities: (1) observer enhanced; (2) unenhanced Sidexis displays; (3) E speed films and (4) F speed film. Histologic sections served as validating criterion for the presence and depth of carious lesions. Diagnostic accuracy was measured as the area beneath the ROC curve. Results: Mean ROC (receiver operating characteristic) curve areas for approximal surfaces were 0.865 (E speed), 0.856 (F speed), 0.816 (unenhanced Sidexis) and 0.776 (observer enhanced). There were no significant differences between unenhanced digital Sidexis and films. Observer enhanced Sidexis images exhibited a statistically significant lower diagnostic accuracy than the film images for two of the observers.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The pathophysiology of neurodegenerative diseases (ND) such as Alzheimer's disease (AD) and Parkinson's disease (PD) has not yet been completely elucidated. However, in the past few years, there have been great knowledge advances about intra-and extracellular proteins that may display impaired function or expression in AD, PD and other ND, such as amyloid beta (AB), alpha-synuclein, tau protein and neuroinfiammatory markers. Recent developments in the imaging techniques of positron emission tomography (PET) and single photon emission computed tomography (SPECT) now allow the non-invasive tracking of such molecular targets of known relevance to ND in vivo. This article summarizes recent findings of PET and SPECT studies using these novel methods, and discusses their potential role in the field of drug development for ND as well as future clinical applications in regard to differential diagnosis of ND and monitoring of disease progression.

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Programa de Doctorado: Ingeniería de Telecomunicación Avanzada.

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Fish oil (FO) has immunomodulating effects and may improve organ function and outcome in critically ill patients. This retrospective, propensity-matched cohort study investigates the effects of early intravenous FO supplementation on organ failure in patients with septic shock from abdominal infection.

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Hatchet blows to the human skull often cause fatal injuries. We present a case of homicide by hatchet blow that underwent CT, MRI, and autopsy examination. Skull fragmentation, fracture lines, and brain injuries were demonstrated prior to autopsy. Many of the hatchet-specific characteristics (flaking, crushing, shattering, and fracture lines) described in literature were observed in the post-mortem imaging of this case.

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On 1 July 2007 a new transplant law came into force in Switzerland. The principal item of this new law is the change from centre-oriented allocation to patient-oriented national allocation of organs. The aim of the present study is to assess the impact on cold ischaemia time (CIT) and transport requirements.

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Magnetic iron oxide nanoparticles have found application as contrast agents for magnetic resonance imaging (MRI) and as switchable drug delivery vehicles. Their stabilization as colloidal carriers remains a challenge. The potential of poly(ethylene imine)-g-poly(ethylene glycol) (PEGPEI) as stabilizer for iron oxide (γ-Fe₂O₃) nanoparticles was studied in comparison to branched poly(ethylene imine) (PEI). Carrier systems consisting of γ-Fe₂O₃-PEI and γ-Fe₂O₃-PEGPEI were prepared and characterized regarding their physicochemical properties including magnetic resonance relaxometry. Colloidal stability of the formulations was tested in several media and cytotoxic effects in adenocarcinomic epithelial cells were investigated. Synthesized γ-Fe₂O₃ cores showed superparamagnetism and high degree of crystallinity. Diameters of polymer-coated nanoparticles γ-Fe₂O₃-PEI and γ-Fe₂O₃-PEGPEI were found to be 38.7 ± 1.0 nm and 40.4 ± 1.6 nm, respectively. No aggregation tendency was observable for γ-Fe₂O₃-PEGPEI over 12 h even in high ionic strength media. Furthermore, IC₅₀ values were significantly increased by more than 10-fold when compared to γ-Fe₂O₃-PEI. Formulations exhibited r₂ relaxivities of high numerical value, namely around 160 mM⁻¹ s⁻¹. In summary, novel carrier systems composed of γ-Fe₂O₃-PEGPEI meet key quality requirements rendering them promising for biomedical applications, e.g. as MRI contrast agents.

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BACKGROUND: The aim of this study was to investigate the biochemical properties, histological and immunohistochemical appearance, and magnetic resonance (MR) imaging findings of reparative cartilage after autologous chondrocyte implantation (ACI) for osteochondritis dissecans (OCD). METHODS: Six patients (mean age 20.2 +/- 8.8 years; 13-35 years) who underwent ACI for full-thickness cartilage defects of the femoral condyle were studied. One year after the procedure, a second-look arthroscopic operation was performed with biopsy of reparative tissue. The International Cartilage Repair Society (ICRS) visual histological assessment scale was used for histological assessment. Biopsied tissue was immunohistochemically analyzed with the use of monoclonal antihuman collagen type I and monoclonal antihuman collagen type II primary antibodies. Glycosaminoglycan (GAG) concentrations in biopsied reparative cartilage samples were measured by high performance liquid chromatography (HPLC). MR imaging was performed with T1- and T2-weighted imaging and three-dimensional spoiled gradient-recalled (3D-SPGR) MR imaging. RESULTS: Four tissue samples were graded as having a mixed morphology of hyaline and fibrocartilage while the other two were graded as fibrocartilage. Average ICRS scores for each criterion were (I) 1.0 +/- 1.5; (II) 1.7 +/- 0.5; (III) 0.6 +/- 1.0; (IV) 3.0 +/- 0.0; (V) 1.8 +/- 1.5; and (VI) 2.5 +/- 1.2. Average total score was 10.7 +/- 2.8. On immunohistochemical analysis, the matrix from deep and middle layers of reparative cartilage stained positive for type II collagen; however, the surface layer did not stain well. The average GAG concentration in reparative cartilage was 76.6 +/- 4.2 microg/mg whereas that in normal cartilage was 108 +/- 11.2 microg/mg. Common complications observed on 3D-SPGR MR imaging were hypertrophy of grafted periosteum, edema-like signal in bone marrow, and incomplete repair of subchondral bone at the surgical site. Clinically, patients had significant improvements in Lysholm scores. CONCLUSIONS: In spite of a good clinical course, reparative cartilage after ACI had less GAG concentration and was inferior to healthy hyaline cartilage in histological and immunohistochemical appearance and on MRI findings.