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  • 1995-1999  (2)
  • 1985-1989  (2)
  • Animal studies  (2)
  • hydrocephalus  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Cavum vergae cyst as a cause of hydrocephalus, “Almost Forgotten”? (1986)
    Springer
    Acta neurochirurgica 83 (1986), S. 12-19 
    Details
    ISSN: 0942-0940
    Keywords: Intracerebral midline cysts ; cavum vergae ; developmental cystic malformations ; hydrocephalus ; stereotactic surgery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cavum vergae cysts (CVC) are cerebral midline malformations, which usually have no clinical manifestations. In rare cases, however, non-communicating cysts can cause hydrocephalus by obstruction of the aqueduct. Initially, from 1930 to 1960 operative treatment consisted in open cysto-ventriculostomy,i.e. establishing a communication between CVC and the ventricles, via a transventricular approach. In the era of CT, symptomatic treatment of the hydrocephalus by ventriculo-atrial or ventriculo-peritoneal sunts is preferred. All the wellknown complications of shunting are encountered. Based on the experience of our cases of CVC with clinical manifestations, we here propose a definitive causal treatment which can be achieved by draining the cyst contents into the ventricles via a stereotactically introduced catheter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01420502
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Colloid cysts of the third ventricle (1986)
    Springer
    Acta neurochirurgica 83 (1986), S. 24-30 
    Details
    ISSN: 0942-0940
    Keywords: Colloid cysts ; hydrocephalus ; stereotactic puncture ; third ventricle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Colloid cysts of the third ventricle can cause hydrocephalus if they grow to the point where they occlude the foramina interventricularia. The operative approach via a craniotomy used to be the common method of treating these lesions. Now, in the era of CT- and MR-scanning, stereotactic aspiration should be preferred as an ideal method of simultaneously diagnosing and treating colloid cysts. Unlike open surgery, aspiration of colloid masses poses hardly any risk for the patient. Ten cases successfully treated by this technique are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01420504
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Use of scanner characteristics in iterative image reconstruction for high-resolution positron emission tomography studies of small animals (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 779-786 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Positron emission tomography ; Spatial resolution ; Image restoration ; Animal studies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The purpose of this work was to improve of the spatial resolution of a whole-body positron emission tomography (PET) system for experimental studies of small animals by incorporation of scanner characteristics into the process of iterative image reconstruction. The image-forming characteristics of the PET camera were characterized by a spatially variant line-spread function (LSF), which was determined from 49 activated copper-64 line sources positioned over a field of view (FOV) of 21.0 cm. This information was used to model the image degradation process. During the course of iterative image reconstruction, the forward projection of the estimated image was blurred with the LSF at each iteration step before the estimated projections were compared with the measured projections. The imaging characteristics of the high-resolution algorithm were investigated in phantom experiments. Moreover, imaging studies of a rat and two nude mice were performed to evaluate the imaging properties of our approach in vivo. The spatial resolution of the scanner perpendicular to the direction of projection could be approximated by a one-dimensional Gaussian-shaped LSF with a full-width at half-maximum increasing from 6.5 mm at the centre to 6.7 mm at a radial distance of 10.5 cm. The incorporation of this blurring kernel into the iteration formula resulted in a significantly improved spatial resolution of about 3.9 mm over the examined FOV. As demonstrated by the phantom and the animal experiments, the high-resolution algorithm not only led to a better contrast resolution in the reconstructed emission scans but also improved the accuracy for quantitating activity concentrations in small tissue structures without leading to an amplification of image noise or image mottle. The presented data-handling strategy incorporates the image restoration step directly into the process of algebraic image reconstruction and obviates the need for ill-conditioned ”deconvolution” procedures to be performed on the projections or on the reconstructed image. In our experience, the proposed algorithm is of special interest in experimental studies of small animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00879667
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Use of scanner characteristics in iterative image reconstruction for high-resolution positron emission tomography studies of small animals (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 779-786 
    Details
    ISSN: 1619-7089
    Keywords: Positron emission tomography ; Spatial resolution ; Image restoration ; Animal studies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The purpose of this work was to improve of the spatial resolution of a whole-body positron emission tomography (PET) system for experimental studies of small animals by incorporation of scanner characteristics into the process of iterative image reconstruction. The image-forming characteristics of the PET camera were characterized by a spatially variant line-spread function (LSF), which was determined from 49 activated copper-64 line sources positioned over a field of view (FOV) of 21.0 cm. This information was used to model the image degradation process. During the course of iterative image reconstruction, the forward projection of the estimated image was blurred with the LSF at each iteration step before the estimated projections were compared with the measured projections. The imaging characteristics of the high-resolution algorithm were investigated in phantom experiments. Moreover, imaging studies of a rat and two nude mice were performed to evaluate the imaging properties of our approach in vivo. The spatial resolution of the scanner perpendicular to the direction of projection could be approximated by a one-dimensional Gaussian-shaped LSF with a full-width at half-maximum increasing from 6.5 mm at the centre to 6.7 mm at a radial distance of 10.5 cm. The incorporation of this blurring kernel into the iteration formula resulted in a significantly improved spatial resolution of about 3.9 mm over the examined FOV As demonstrated by the phantom and the animal experiments, the high-resolution algorithm not only led to a better contrast resolution in the reconstructed emission scans but also improved the accuracy for quantitating activity concentrations in small tissue structures without leading to an amplification of image noise or image mottle. The presented data-handling strategy incorporates the image restoration step directly into the process of algebraic image reconstruction and obviates the need for ill-conditioned ”deconvolution“ procedures to be performed on the projections or on the reconstructed image. In our experience, the proposed algorithm is of special interest in experimental studies of small animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00879667
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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