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- Boegård, Torsten, et al.
(författare)
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Postero-anterior radiogram of the knee in weightbearing and semiflexion. Comparison with MR imaging
- 1997
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Ingår i: Acta Radiologica. - : SAGE Publications. - 0001-6926 .- 0284-1851 .- 1600-0455. ; 38:6, s. 1063-1070
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: the purpose was four-fold: to assess the reproducibility of p.a. weight-bearing radiograms of the knee and the minimal joint-space (MJS) width measurements in these radiograms; to compare the MJS with MR-detected cartilage defects; to evaluate the location of these cartilage defects; and to estimate the relation between meniscal abnormalities and joint-space narrowing Material and Methods: Fifty-nine individuals, aged 41–58 years (mean 50), with chronic knee pain were examined by means of p.a. weight-bearing radiograms in semi-flexion with fluoroscopic guidance of the knee joint. the MJS was measured with a standard ruler. on the same day MR imaging was performed with proton-density- and T2-weighted turbo spin-echo on a 1.0 T imager. Meniscal abnormalities and cartilage defects in the tibiofemoral joint (TFJ) were noted Results and Conclusion: the p.a. view of the knee and the MJS measurements were reproducible. MJS of 3 mm is a limit in diagnosing joint-space narrowing in knees with MR-detected cartilage defects. There was a high proportion <p<0.001) of meniscal abnormality within the narrowed compartments in comparison with those that were not narrowed. A larger number of the cartilage defects (p<0.05) was found in the medial femoral condyle than in any of the other condyles of the TFJ. the defects had a dorsal location <p<0.001) as shown in the weight-bearing radiograms of the knee in semiflexion
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- Jonsson, A, et al.
(författare)
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Radiation dose reduction in computed skeletal radiography. Effect on image quality.
- 1996
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Ingår i: Acta Radiologica. - 0001-6926. ; 2:37, s. 128-133
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To evaluate the effect of radiation dose reduction on image ++quality in computed musculoskeletal radiography and determine optimal exposure range. MATERIAL AND METHODS: In 11 corpses, 1 hand and 1 hip were examined with film-screen radiography, and a series of computed radiographs was obtained using exactly the same technique except for the exposure, which was 100, 50, 25, 12.5, 6.25, and 1.56% of the mAs numbers used for the film-screen images. The computed hip radiographs were processed in 2 different ways, one simulating the film-screen images and one using contrast enhancement. Four radiologists reviewed the images regarding the following parameters: cortical bone, trabecular bone, joint space, and soft tissue, giving each a diagnostic quality rating on a scale from 1 to 5. The median and mean values were found for the pooled results. RESULTS: For the hands, the computed radiographs were ranked inferior to the film-screen images for all parameters except soft tissue, where the computed radiographs scored higher. The computed images with 50 and 25% exposure were ranked equal to the 100% ones. The quality rating slowly declined with lower exposures. For the hips, the 100 and 50% computed radiographs were generally similar to or slightly better than the film-screen images. The decline was somewhat faster than for the hands. The contrast-enhanced hip images scored less than the nonenhanced images at any given exposure for all parameters except soft tissue, where the contrast-enhanced images scored better at all exposures. The difference between nonenhanced and enhanced images became less at the lower exposures. CONCLUSION: Lowering the exposure in computed musculoskeletal radioagrphy below the level of film-screen radiography is feasible, especially in the peripheral skeleton. Contrast enhancement seems to be valuable only in the evaluation of soft-tissue structures.
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- Auer, R., et al.
(författare)
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The dentate gyrus in hypoglycemia : Pathology implicating excititoxin-mediated neuronal necrosis
- 1985
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Ingår i: Acta Neuropathologica. - 0001-6322. ; 67:3-4, s. 279-288
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Tidskriftsartikel (refereegranskat)abstract
- A detailed light- and electron-microscopic study of the damage to the rat dentate gyrus in hypoglycemia was undertaken, in view of the previously advanced hypothesis that hypoglycemic nerve cell injury is mediated by a released neurotoxin. The distribution of neuronal necrosis showed a relationship to the subarachnoid cisterns. Electron microscopy of the dentate granule cells and their apical dendrites revealed dendrosomal, axon-sparing neuronal pathology. Dentate granule cells were affected first in the dendrites in the outer layer of the stratum moleculare, sparing axons of passage and terminal boutons. Subsequently, the neuronal perikarya were affected, and Wallerian degeneration of axons followed. Cell membrane abnormalities preceded the appearance of mitochondrial flocculent densities and degradation of the cytoskeleton, and are suggested to be early lethal changes. The observed early dendrotoxic changes, and the dendrosomal, axon-sparing nature of the lesion implicate an excitotoxin-mediated neuronal necrosis in hypoglycemia.
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