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  • 1
    ISSN: 1600-0846
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background/aims: An experimental model for the preclinical evaluation of contrast enhancement patterns in melanoma was developed.Methods: Melanotic and amelanotic tumor cells B16F1 and B16a implanted into murine skin were depicted with magnetic resonance imaging (MRI) at a pixel size of 78×78 urn and 1 mm slice thickness. Tumor signal intensities were evaluated in user defined ROIs (regions of interest). Signal intensity changes were determined from signal intensity-time curves. Percent enhancement, slope of the signal intensity curve and percent signal intensity increase were also determined. Percent enhancement was calculated: (SIenhanced-SIpiain)/SIplain× 100 [SI=signal intensity]. The slope of the signal intensity curve was calculated: (SImax-SIplain)/(SIplain× SImax) × 100 (%/min). Percent signal intensity increase was calculated: (SImax-SIplai)/SIplain× 100.Results: Following i.v. administration of Gd-DTPA and G-DTPA-polylysine, all tumors showed pronounced contrast enhancement. Contrast enhancement and the slope of signal intensity to time curves did not distinguish melanotic from amelanotic melanomas (P〉0.05).Conclusions: The animal model presented is well suited for evaluation of contrast enhancement in melanoma by MRI. Contrast enhancement of melanoma in MRI is comparable with the enhancement seen in other tumors.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1437-2320
    Keywords: Key words Stereotaxy ; Accuracy ; Localisation frame ; Computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The accuracy of coordinate transformation from the computed tomographic (CT) space to the stereotactic frame space was analysed for frame-based stereotactic systems which use a localisation frame and coordinate transformation based on matrix calculation. The coordinate transformation was divided into three consecutive steps: (1) transforming the localisation frame into the CT image built up from pixels with distinct attenuation values, (2) determining the rod centres of the localisation frame in the CT image, and (3) coordinate transformation from the image to the frame space using the centres of the rods in the image space and algebraic, matrix-based calculation. The error contribution at each step was evaluated separately and its effect on the subsequent mathematical operations was analysed. The first step dealt with the influences of the mathematical and physical properties of the CT on the image of the localisation frame. Noise, slice thickness, convolution filter, dimension of the pixel matrix, and image processing had an influence on the attenuation values in each pixel. Above all, the slice thickness had an effect on the shape of the oblique rods in the CT image. At the second step, the main error contribution was due to the method by which the centre of the rods was calculated. The most accurate method was to determine the centre of gravity using the attenuation values as single mass points (with accuracy in the range of ±1/10 pixel, or ±0.125 mm), followed by rounding off the centre of gravity and the highest pixel value in the square matrix R2(N) within 1 pixel. Pointing with a cursor under visual control was accurate to 1 pixel and the pixel with the highest attenuation value showed deviations of up to 2 pixels in the x and y axes. Thus, the methods differed by a factor of 20. The influence of the CT mathematics and physics on the determination of the centre of the fiducials was negligible in comparison to the method of calculation used. There was no systemic error due to the filtred back projection algorithm. Data input errors due to noise were in the range of 1/10 pixel. The effects of the remaining physical influences were all in the range of the error due to noise. In particular these results speak in favour of no influence of slice thickness on coordinate transformation.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0851
    Keywords: Key words Renal cell cancer ; Tumor-infiltrating lymphocytes (TIL) ; Interleukin-10
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Human renal cell cancer (RCC) is clearly responsive to immunotherapy. Clinical responses may be mediated by “non-specific” (e. g. natural killer, NK, cells) or “specific” MHC-class-I-restricted tumor-specific CD8+ T lymphocytes. Typically RCC progresses, however, despite significant infiltration of various lymphoid cells. We examined freshly isolated RCC tumor-infiltrating lymphocytes (TIL) derived from seven RCC patients for cytokine expression by the polymerase chain reaction (PCR). Established RCC tumor cell lines derived from these RCC patients were negative for interleukin-2 (IL-2), IL-4, IL-10, and interferon γ and found to be positive for tumor necrosis factor α (TNFα), IL-6, IL-1β, granulocyte/macrophage-colony-stimulating factor (GM-CSF), and transforming growth factor β1 (TGFβ1) message as detected by PCR. An identical pattern of cytokine mRNA expression was identified in other long-term RCC lines and in normal human kidney cells upon culture, but not in two Wilms tumor cell lines tested. Short-term-, and long-term-established RCC lines, but not Wilms tumor lines, secreted substantial levels of GM-CSF, TNFα, IL-1β, and IL-6 as detected by enzyme-linked immunosorbent assay. Both RCC lines and Wilms tumor lines secreted TGFβ1. In comparison, normal kidney cells secreted IL-6 and GM-CSF, but not IL-1β, or TFGβ1 under identical in vitro cell culture conditions. We applied PCR-based methods to characterize the cytokine mRNA expression pattern in immune cells infiltrating into renal cell cancer without the need for expansion of such effector cells in vitro. Examining freshly collected RCC TIL by PCR from patients with primary cell cell cancer, we could demonstrate that such cells, but not lympho-mononuclear cells harvested from normal human kidney tissue, typically exhibit IL-4 and IL-10 mRNA expression.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0509
    Keywords: Cocaine ; Body packers ; Drug smuggling ; Abdominal ultrasound ; Abdominal x-ray
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose To evaluate the imaging characteristics and the diagnostic value of both abdominal ultrasound and conventional abdominal x-ray in identifying ingested drug packages in “body packers.” Materials and Methods Twelve individuals were studied prospectively by abdominal ultrasound and by abdominal x-ray to rule out incorporated drug containers. Results Both abdominal ultrasound and abdominal x-ray correctly identified the 7 of 12 individuals who had ingested multiple drug packages. In 5 of the 12 individuals, ultrasound as well as abdominal x-ray were correctly unremarkable with regard to abdominal foreign bodies. Conclusions Abdominal ultrasound and abdominal x-ray both represent valuable diagnostic tools in the assessment of ingested drug packages. Abdominal x-ray is superior to ultrasound in differentiating ingested drug-filled condoms from “pseudocondoms.”
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1238
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1238
    Keywords: Key words Acute respiratory distress syndrome (ARDS) ; Chest radiography ; Extracorporeal membrane oxygenation ; Lung biopsy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective: To determine whether the quality of infiltrations in chest radiographs can accurately predict the histological extent of fibrotic change in patients with acute respiratory distress syndrome (ARDS). Design: Retrospective clinical investigation. Setting: Intensive care unit (ICU) of a university teaching hospital. Patients and methods: Of 47 patients treated with extracorporeal membrane oxygenation (ECMO) for severe ARDS over a 5-year period, 23 patients underwent open lung biopsy at thoracotomy for treatment, mostly of pneumothorax. Chest films obtained by portable chest roentgenography preceding the operation were reviewed retrospectively and compared to the histomorphological results of the lung specimen. Results: Chest radiographs displayed mixed alveolar-reticular opacification in 60.2 %, alveolar patterns in 22.9 % and reticular opacities in 10.5 %. In 0.4 % there were no infiltrates, 6 % could not be evaluated because of insufficient quality. There was no relevant difference between the right and left lungs. Subdividing patients into two groups according to the histological results of either absent or mild (1) or severe (2) lung fibrosis, we found an alveolar haziness in 12.3 % in group 1 compared with 28.2 % in group 2, while reticular characteristics were identified in 13 % and 11 %, respectively. Conclusions: The most common opacity in chest radiographs of patients with severe ARDS treated with ECMO is mixed alveolar-reticular opacification. Severe lung fibrosis is not positively correlated with a reticular radiographic pattern. ECMO does not lead to specific radiological changes in conventional radiograms, contrary to clinical findings that treatment with ECMO might induce pleural or pulmonic haemorrhage, especially in the earlier days when systemic heparinization had to be used instead of the heparin-coated tube-surfacing.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1084
    Keywords: MR ; Perfusion study ; Brain ; Necrosis ; Edema ; Neoplasms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of this study was to characterize intracranial tumors based on MR measurements of regional cerebral blood volume. In 8 patients without intracranial pathology and 42 patients with intracranial tumors a T2*-weighted image series was acquired during bolus injection of gadolinium-DTPA, and regional cerebral blood volume maps were calculated. The regional cerebral blood volume index (rCBVi) of vital tumor was expressed in percent of the value measured in contralateral gray matter. In extra-axial tumors (meningiomas) rCBVi was higher (124 ± 110%), and in low-grade intra axial tumors rCBVi was lower (79 ± 65%), than in contralateral cortex. In malignant intra-axial tumors the distribution of rCBV was heterogenous: high in vital tumor (glioblastomas: rCBVi = 165 ± 85%; metastases: rCBVi = 106 ± 79%), but low in necrosis (rCBVi = 33% of contralateral white matter) and edema (rCBVi = 53% of contralateral white matter). rCBVi was highest in arteriovenous malformations (1053 ± 584% of contralateral gray matter). We conclude that the regional cerebral blood volume distribution is useful to characterize intracranial tumors, although the large biological variability of individual tumor entities indicates limitations.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-1173
    Keywords: Schlüsselwörter Progressive faziale Hemiatrophie ; Romberg-Erkrankung ; Gesicht ; Haut ; Hochauflösende MRT ; Key words Progressive facial hemiatrophy ; Romberg’s disease ; Face ; Skin ; High resolution MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Romberg disease, also known as progressive facial hemiatrophy (PFH), is an uncomman disease with progressive facial asymmetry as the major symptom. It is a atrophic process of the subcutaneous fatty tissue whose etiology is unknown. Skin, muscles and bones can be secondarily afflicted. With MRI evaluation we were able to show in 14 patients with PFH thinner subcutaneous fat, as well as flattening of the dermis in 12 of the 14. We divided the patients into three stages by the means of the MRI findings and found tendency towards concurrence between the MRI stage and the clinical stage.
    Notes: Zusammenfassung Die Romberg-Erkrankung oder progressive faziale Hemiatrophie (PFH) ist ein seltenes Krankheitsbild mit einer fortschreitenden Gesichtsasymmetrie als Leitsymptom. Es handelt sich um einen atrophierenden Prozeß des subkutanen Fettgewebes bislang ungeklärter Ätiologie, wobei Haut, Muskulatur und Knochen betroffen sein können [1, 23]. Wir konnten MR-tomographisch bei allen untersuchten Patienten mit PFH eine Verdünnung der Subkutis sowie zusätzlich bei 12 von 14 Patienten eine „glatte” Dermis darstellen. Die Subkutis war bei 9 Patienten stellenweise nicht abgrenzbar. Wir ordneten die Patienten, die nur eine Verdünnung der Subkutis aufwiesen in ein Stadium 1; Patienten, bei denen zusätzlich ein Verlust der Verzahnung zwischen Dermis und Epidermis festzustellen war in ein Stadium 2 und Patienten, bei denen die Subkutis an einer Stelle überhaupt nicht mehr abgrenzbar war in ein Stadium 3 ein. Ferner war eine tendenzielle Übereinstimmung zwischen MRT-Stadium und dem klinischem Stadium festzustellen.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-1920
    Keywords: Key words Magnetic resonance imaging ; experimental ; Brain stem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Our purpose was to investigate the potential of an experimental animal coil using a commercial MRI unit to delineate the anatomical structure of the human brain stem. Three formaldehyde-fixed brain-stem specimens were examined by MRI and sectioned perpendicular to their longitudinal axis. The images were compared with gross anatomy and myelin-stained histological sections. Fibre tracts and nuclei which were not evident on examination of the unstained specimen were readily identified by MRI. Due to its inherent grey/white matter contrast, MRI with a high-resolution coil delineates anatomical structures in a way comparable to the myelin-stained histological sections. However, pigmented structures, readily visible on examination of the unstained specimen were discernible on neither MRI nor on myelin-stained sections. The excellent anatomical detail and grey/white matter contrast provided by these images could make MRI a useful adjunct to the pathologist investigating brain disease.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-1920
    Keywords: Magnetic resonance imaging, experimental ; Brain stem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Our purpose was to investigate the potential of an experimental animal coil using a commercial MRI unit to delineate the anatomical structure of the human brain stem. Three formaldehyde-fixed brain-stem specimens were examined by MRI and sectioned perpendicular to their longitudinal axis. The images were compared with gross anatomy and myelin-stained histological sections. Fibre tracts and nuclei which were not evident on examination of the unstained specimen were readily identified by MRI. Due to its inherent grey/white matter contrast, MRI with a highresolution coil delineates anatomical structures in a way comparable to the myelin-stained histological sections. However, pigmented structures, readily visible on examination of the unstained specimen were discernible on neither MRI nor on myelin-stained sections. The excellent anatomical detail and grey/white matter contrast provided by these images could make MRI a useful adjunct to the pathologist investigating brain disease.
    Type of Medium: Electronic Resource
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