Formation and resolution of white matter oedema in various types of brain tumours.
ABSTRACT Following infusion of 200 ml of Iopamidol for 1 hour the propagation of extravasated contrast medium around different types of 12 brain tumours was examined and imaged via CT. Increasing volume of expanding peritumoural contrast enhanced brain tissue was measured by integrating volumes of planimetrically measured enhanced area on CT slice of 0.5 cm in thickness. So far our data failed to demonstrate differences in the peritumoural contrast expansion between the different types of tumours. Formation and resolution as well as the speed of oedema propagation were determined by calculation of the increasing volume of the enhanced peritumoural brain tissue. Average formation rate of oedema fluid from 1 cm3 of tumour was 0.06 ml/hr, and was lower in larger tumours, while formation rate of oedema fluid from whole tumour was higher in larger tumours. Average resolution rate of oedema fluid during the passage through 1 cm3 of the peritumoural white matter was 0.03 ml/hr, and was not affected by tumour size. Average speed of oedema propagation was 0.59 mm/hr, and was higher in larger tumours. The main therapeutic effect of steroid in peritumoural oedema was a reduction in formation rate of oedema fluid.
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ABSTRACT: We report a group of eight patients with a distinctive histological variant of meningioma that is associated with severe peritumoral edema. The clinical presentation, radiographic findings, and histology of this type of tumor may lead to misdiagnosis as an aggressive or malignant process. We reviewed the histology from patients who had removal of meningiomas performed in our institution between 1978 and 1992. Tumors having abnormal proliferation of cells in the intramural vascular spaces were selected for study; case histories and radiographs were reviewed. Tumor material was subjected to special stains, immunocytochemical examination, and election microscopy. Several lesions were misread radiographically as being malignant. Patients underwent craniotomy with complete excision of the tumor. All lesions were small (< or = 3 cm), and no brain invasion, unusual tumor vascularity, or dural sinus involvement was noted in any case. Histologically, the meningioma pattern in each case was meningothelial and benign in appearance. The immunocytochemical and electron microscopic features of the unusual cells in the blood vessel walls are most consistent with their being of pericytic origin. All patients have remained asymptomatic and without evidence of tumor recurrence with follow-up from 3 to 12 years. These tumors showed proliferation of pericytes in blood vessel walls and represent a new subtype of meningothelial meningioma. The apparently benign nature of these lesions necessitates their recognition. Characteristic findings of pericytic proliferation associated with edema generation have led us to descriptively term this the PEG variant of meningioma.Neurosurgery 11/1996; 39(4):700-6; discussion 706-7. · 2.53 Impact Factor
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ABSTRACT: Among glucocorticoids, dexamethasone is most widely used for treatment of cerebral edema because of its long biological half-life and its low mineralocorticoid activity (sodium retaining). A systematic review of the literature on the effects of dexamethasone on the brain from in vivo studies in humans. A MEDLINE database search (via the PubMed interface) and an EMBASE database search (via the Dialog interface) of the past 35 years was performed. Every article relating to human use reported in English was included. In addition, references of all eligible articles were searched to identify other possible sources. Twenty-four articles matched the eligibility criteria. There were disparate methodologies and conflicting results, although they tended to indicate a decrease in blood-tumor barrier permeability, decreased tumoral perfusion, decreased tumoral diffusivity, and the possibility of decreased perfusion in contralateral normal-appearing brain tissue. Treatment with dexamethasone may alter imaging parameters from cerebral perfusion studies used in the management of brain tumors. In adequately powered studies, it may be possible to assess the longer term effects of dexamethasone on normal brain tissue to help optimize use with longer term survivors that are emerging as improvements in glioma treatment are made.Neurosurgery 12/2010; 67(6):1799-815; discussion 1815. · 2.53 Impact Factor