The patient with symptomatic extracranial carotid artery disease who, on angiography, is found to have a coexisting intracranial aneurysm presents a therapeutic dilemma. Relief of the carotid stenosis, with a potential increase in cerebral blood pressure, might increase the risk of aneurysm rupture. Conversely, repair of the aneurysm may be hazardous because of the low flow imposed by the carotid stenosis, particularly in the event of perioperative hypotension.
View Article and Find Full Text PDFCerebral blood flow mapping with the xenon-enhanced/CT method has become a useful clinical tool in the management of patients with occlusive cerebral vascular disease. Studies involving 4-5 minutes of inhaling a xenon/oxygen mixture (less than or equal to 35%) can now be performed routinely with acceptable patient tolerance and compliance. Four cases with acute and chronic ischemic injuries are reported here to illustrate the manner in which this method has been used to characterize flow pattern in such patients and the relevance of this flow information to clinical patient management.
View Article and Find Full Text PDFAngiographic criteria for the identification of patients with angiographic internal carotid artery occlusion but with anatomical patency are presented. The presence of retained contrast material in a caudal atherosclerotic internal carotid artery stump, especially when accompanied by visualization of the internal carotid artery at the base of the skull, suggests that the internal carotid artery may be patent. Two cases of "extreme" pseudo-occlusion are presented, and the indications for extracranial-intracranial bypass and caudal internal carotid artery stump resection are reviewed.
View Article and Find Full Text PDFA noninvasive technique for measuring local cerebral blood flow (LCBF) by xenon enhanced x-ray transmission computed tomography (CT) has been developed an reported quite extensively in recent years. In this method, nonradioactive xenon gas in inhaled and the temporal changes in radiographic enhancement produced by the inhalation are measured by sequential computed tomography. Time dependent xenon concentrations within various tissue segments in the brain are used to derive both local partition coefficient (lambda) and LCBF.
View Article and Find Full Text PDFPossible errors in the determination of xenon concentrations in arterial blood, and uncertainties in CT tissue enhancements during inhalation of xenon-oxygen mixtures, are used to assess errors in the determination of regional cerebral blood flow by the in vivo autoradiographic (single-scan) technique. The results of this study indicate that errors associated with the determination of xenon concentrations in arterial blood decrease rapidly as the time of scanning after the initiation of xenon inhalation is increased. Analysis of errors caused by statistical uncertainties in image enhancement indicate that time of scanning is optimal between 1.
View Article and Find Full Text PDFA noninvasive technique has been developed to measure and display local cerebral blood flow (LCBF) in vivo. In this procedure, nonradioactive xenon gas is inhaled and the temporal changes in radiographic enhancement produced by the inhalation are measured by sequential computerized tomography. The time-dependent xenon concentrations in various anatomical units in the brain are used to derive both the local partition coefficient and the LCBF.
View Article and Find Full Text PDFRadiopaque silicone rubber provides uniquely high degree of vascular definition when combined with xeroradiography for visualization of the cerebral circulation. The method of tissue preparation is described and illustrated by xeroradiograms of coronal sections of brains from animals subjected to occlusion of the lenticulostriate artery.
View Article and Find Full Text PDFA highly reliable model for the study of focal cerebral ischemia has been developed using a retro-orbital approach to occlude the lateral lenticulostriate arteries of the baboon. An infarction of the caudate, putamen and the anterior limb of the internal capsule has consistently been produced. Reliability has been attained because the anatomical variations of the lenticulostriate arteries of each animal can be fully appraised, permitting selective vessel occlusion.
View Article and Find Full Text PDFXenon and iodine enhanced dynamic computerized tomography (CT) have been used experimentally to obtain both qualitative and quantitative information on local cerebral blood flow in both normal and infarcted tissue. Direct comparisons between Xenon enhancement, iodine enhancement and pathological findings demonstrate significant differences between results derived from each of the 2 in vivo techniques. While iodine enhanced dynamic CT yields valuable information concerning the patency and density of vasculature, xenon enhanced studies can provide highly focal information on cerebral tissue perfusion.
View Article and Find Full Text PDFShort- and long-term side effects during and after inhalation of premixed xenon oxygen (28-47%) from 12 studies are reported. While all but one subject tolerated xenon inhalation without ill effects, that individual did experience unpleasantly severe dysesthesias and a brief period of unresponsiveness. We believe that further human studies with xenon inhalation should be conducted to explore possible early indicators for reduced tolerance of xenon by certain individuals.
View Article and Find Full Text PDFJ Comput Assist Tomogr
June 1981
Xenon enhanced computed tomography with a fast scanning mode and interscan table incrementation was used to derive local cerebral blood flow in a nonhuman primate 19 days following infarction. The in vivo autoradiographic methodology was used to derive blood flow in normal and diseased tissue at four different brain levels (slices) during a single inhalation study.
View Article and Find Full Text PDFSodium thiopental was administered to 10 dogs following embolization of the middle cerebral artery. Its effect on the "grace period" for revascularization was investigated by performing embolectomies 6 hours later. We observed a striking reduction in the size of infarction in the animals treated with thiopental at moderate and prolonged dosage levels.
View Article and Find Full Text PDFNeurosurgery
November 1980
This paper reports a case of a true aneurysm of the intracranial internal carotid artery that occurred after a closed head injury. The probable etiology of this unusual lesion is discussed in respect to other partial and complete vessel wall injuries. The diagnosis of a traumatic aneurysm must be suspected when a delayed intracranial hemorrhage occurs after a head injury.
View Article and Find Full Text PDFAn anomaly of the anterior spinal artery in association with a berry aneurysm is reported. The embryological basis for this previously unreported combination is reviewed.
View Article and Find Full Text PDFXenon-enhanced computed tomography (CT) was used to analyze, in vivo, the patterns of blood flow of cerebral infarction in a nonhuman primate model. Consistent and reproducible results were attained utilizing the numerical data from CT scans obtained during the inhalation of nonradioactive xenon. The spatial resolution of CT defined a morphophysiologic map of the variability in brain:blood partition coefficient and flow rate constant that exist within and around an infarct.
View Article and Find Full Text PDFTwo cases of very small trigeminal neurinomas arising proximal to Meckel's cave are presented. We believe that the overlap of the symptoms and signs of these tumors with those of atypical trigeminal neuralgia strengthens the concept of the latter entity also being due to compression of the trigeminal nerve solely within the posterior fossa.
View Article and Find Full Text PDFTo the accepted classification of three types of normal pressure, nontraumatic cerebrospinal fluid (CSF) fistulas, we would add "acquired." This type of CSF fistula tends to occur from the middle cranial fossa because of the enlargement of "pitholes" that are normally present in its anterior medial aspect. The enlargement of these bony defects is due to normal intracranial pressure variations that, not uncommonly, create meningoceles and meningoencephaloceles.
View Article and Find Full Text PDFA rationale for management of the patient with an acute adbomen and a ventriculoperitoneal shunt is presented in relation to eight patients. In two patients peritonitis was due to perforation of an abdominal viscus, not shunt related, and six were due to infections of ventriculoperitoneal shunts. Resolution of abdominal symptomatology occurs within six hours after the distal end of the shunt catheter is removed from the abdomen and placed in a drainage bottle.
View Article and Find Full Text PDFActa Neurochir Suppl (Wien)
November 1979
Thiopentone (20 mg/kg/bolus and 20 mg/kg/three hours) was effective in preventing infarction in five dogs with six hours of middle cerebral occlusion. Nine control animals sustained massive to large infarctions. Utilizing this regime therapeutic blood levels were rapidly attained for over 12 hours without side effects.
View Article and Find Full Text PDFSurg Neurol
February 1978
The experience of the senior author was 16 anterior choroidal artery aneurysms is reviewed. The anatomic variations of the origin of the anterior choroidal artery are discussed, and the danger of sacrificing the artery in aneurysm surgery is stressed. The surgical procedure upon these aneurysms has frequently been difficult, requiring careful microdissection.
View Article and Find Full Text PDFThe clinical, operative and pathological characteristics of a dissecting aneurysm of the vertebral artery are presented. A review of the literature suggests that this type of intracranial aneurysm is being recognized with increasing frequency and can be characterized by its symptomatology and radiological patterns. A set of guidelines for the management of dissecting intracranial aneurysms is proposed.
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