Xenon-enhanced CT CBF measurements in cerebral AVM's before and after excision

Abstract

Unlike neurological deficits resulting from intracranial hemorrhage in patients with cerebral arteriovenous malformation (AVM), which have well defined etiology, the pathogenesis and treatment of progressive and/or fluctuating non-hemorrhagic neurological and psychological deficits require clarification. Values for local cerebral blood flow (LCBF) and local partition coefficients (L lambda) were measured by the method using stable xenon (Xe)-computerized tomography (CT-CBF) scanning, and were compared to 133Xe inhalation values using external probes in 16 patients with cerebral AVM's. Values were measured by both methods before and after total excision of AVM's in five cases. Neurological and mental status assessments were compared with LCBF results. Clinical improvement was most evident after total excision of AVM's. Other procedures, such as clipping of vessels, partial excision, and ventriculoperitoneal shunting for hydrocephalus, were associated with frequent complications. Embolization carried risks of cerebral infarction and was not efficacious unless combined with excision. Medical treatment resulted in poor or unsuccessful seizure control, with neurological deterioration despite anticonvulsant therapy. Compared with age-matched normal individuals, LCBF values in patients with AVM's were significantly reduced, particularly adjacent to the AVM's. Mean L lambda values for gray and white matter were normal. After excision, LCBF values in gray and white matter increased significantly up to normal. Due to overestimation of CBF by shunt flow with the 133Xe method of measurement, no correlation was found with results of the CT-CBF method before AVM excision, but significant correlation of the two methods resulted after excision. If accurate LCBF values are obtained by high resolution, direct measurement of tracer clearance from brain tissue, progressive and/or fluctuating neuropsychological deficits correlate with the degree of cerebral steal.

Intracranial hypertension after resection of cerebral arteriovenous malformations. Predisposing factors and management strategy.

“…2 -1 " 9 - 40 Our own SPECT perfusion studies are in agreement with these findings. SPECT studies represented a sensitive index of hemodynamic features that might predispose to postoperative intracranial hypertension.…”

“…' 40 A delayed control scintillation scan was often performed to assist with the delineation of the AVM nidus, which persisted as an area of hypoperfusion after redistribution of the tracer in the rest of the brain. Parenchymal hypoperfusion was classified as adjacent, remote ipsilateral, or remote contralateral to the AVM nidus.…”

Seizure outcomes following radiosurgery for cerebral arteriovenous malformations

“…Additionally, these surgically induced seizures may become progressively more intractable. 49,52,66 The reported risk of new-onset seizures after microsurgical resection varies widely, ranging from 3% to 32%. 1,19,29,33,52,66 In contrast, SRS appears to confer a lower seizure risk for patients without pretreatment seizures, with rates ranging from 0% to 7%.…”

Patterns of Cortical Oxygen Saturation Changes During CO 2 Reactivity Testing in the Vicinity of Cerebral Arteriovenous Malformations

“…Here, a so-called patchy hypoperfusion has been considered AVM specific 23 until proved otherwise 20,24,25 and now is well explained by theories regarding regulation of capillary circulation. 26 Compared with other modalities, the spatial resolution of our methods is higher.…”