Journal of neurosurgery
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Journal of neurosurgery · Jan 2005
Analyzing 3-tesla magnetic resonance imaging units for implementation in radiosurgery.
The limiting factor affecting accuracy during gamma knife surgery is image quality. The new generation of magnetic resonance (MR) imaging units with field strength up to 3 teslas promise superior image quality for anatomical resolution and contrast. There are, however, questions about chemical shifts or susceptibility effects, which are the subject of this paper. ⋯ The 3-tesla imaging unit showed superior anatomical contrast and resolution in comparison with the established 1-tesla and 1.5-tesla units; however, due to the high field strength the field within the head coil is very sensitive to inhomogeneities and therefore 3-tesla imaging data will have be handled with care.
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Journal of neurosurgery · Jan 2005
Microsurgical anatomy of cerebral revascularization. Part II: posterior circulation.
Revascularization is an important component of treatment for complex aneurysms, skull base tumors, and vertebrobasilar ischemia in the posterior circulation. In this study, the authors examined the microsurgical anatomy related to cerebral revascularization in the posterior circulation and demonstrate various procedures for bypass surgery. ⋯ Although a clear guideline for cerebral revascularization procedures has not yet been established, it is important to understand various microsurgical techniques and their related anatomical structures. This will help surgeons consider surgical indications for treatment of patients with vertebrobasilar ischemia caused by aneurysms, tumors, or atherosclerotic diseases in the posterior circulation.
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Journal of neurosurgery · Jan 2005
Gamma knife surgery for vestibular schwannoma: 10-year experience of 195 cases.
The authors conducted a study to determine the optimal radiation dose for vestibular schwannoma (VS) and to examine the histopathology in cases of treatment failure for better understanding of the effects of irradiation. ⋯ Radiosurgery had a long-term radiation effect on VSs for up to 5 years. A margin 12-Gy dose with homogeneous distribution is effective in preventing tumor progression, while posing no serious threat to normal cranial nerve function.
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Journal of neurosurgery · Jan 2005
Ultrastructural changes in arteriovenous malformations after gamma knife surgery: an electron microscopic study.
The authors analyzed morphological alterations at the subcellular level by undertaking transmission electron microscopy in arteriovenous malformations (AVMs) after gamma knife surgery (GKS). ⋯ The ultrastructural and histological characteristics of the spindle cell population in the GKS-treated AVMs are similar to those designated as myofibroblasts in wound healing processes and pathological fibromatoses. Because similar cell modifications have not been demonstrated in control nonirradiated AVM specimens, these myofibroblasts may contribute to the shrinking process and final occlusion of AVMs after radiosurgery.
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Journal of neurosurgery · Jan 2005
How low can you go? Intracranial pressure, cerebral perfusion pressure, and respiratory obstruction in children with complex craniosynostosis.
Elevated intracranial pressure (ICP) is a well-recognized complication affecting children suffering from complex forms of craniosynostosis. The effects of ICP, including those on vision, and the underlying mechanisms involved remain uncertain. The aim of this study was to examine the relationships among ICP, cerebral perfusion pressure (CPP), and the episodic alterations in respiratory obstruction that are common in children with craniosynostosis. ⋯ The findings of this study indicate that ICP, CPP, and respiratory obstruction interact in a vicious cycle, an observation that helps explain the pattern of plateau waves of elevated ICP characteristic among children with complex forms of craniosynostosis. The data gathered in this series revealed levels of CPP considerably lower than those described previously in clinical reports. Such reductions in CPP most likely contribute to the neurological, cognitive, and ophthalmological morbidity from which these children suffer frequently; therefore, the results of this study have important implications for the management of children with complex forms of craniosynostosis as well as for our understanding of the control of cerebral blood flow in general.